WO2011060554A1 - Presolidified composition and method for in situ delivery of broad molecular weight range of chitosan implants with or without therapeutics for regenerative medicine and cartilage repair applications - Google Patents

Abstract

The present description relates to a presolidified implant composition, a method for its preparation, and a use of said implant composition for repairing tissue of a patient wherein the implant comprises a blood component, a salt and a polymer which are solidified in a glass or plastic recipient prior to being administered to the patient. The implants are preferably prepared using chitosan as the polymer and may further comprise therapeutics for in vivo release. The presolidified implants are useful for regenerate e medicine and cartilage repair applications.

Description

PRESOLIDIFIED COMPOSITION AND METHOD FOR IN SITU DELIVERY OF BROAD MOLECULAR WEIGHT RANGE OF CHITOSAN IMPLANTS WITH OR WITHOUT THERAPEUTICS FOR REGENERATIVE MEDICINE AND CARTILAGE REPAIR APPLICATIONS

TECHNICAL FIELD

[0001] The present description relates to a solidified implant composition, method of preparing same and use of the composition for repairing tissue of a patient comprising a blood component, a salt and a polymer.

BACKGROUND ART

[0002] Articular cartilage covers the ends of bones in diarthroidial joints in order to distribute the forces of locomotion to underlying bone structures while simultaneously providing nearly frictionless articulating interfaces.

[0003] Articular cartilage is formed during the development of long bones following the condensation of prechondrocytic mesenchymal cells and induction of a phenotype switch from predominantly collagen type I to collagen type II and aggrecan. Bone is formed from cartilage when chondrocytes hypertrophy and switch to type X collagen expression, accompanied by blood vessel invasion, matrix calcification, the appearance of osteoblasts and bone matrix production. In the adult, a thin layer of articular cartilage remains on the ends of bones and is sustained by chondrocytes through synthesis, assembly and turnover of extracellular matrix. Articular cartilage disease arises when fractures occur due to physical trauma or when a more gradual erosion, as is characteristic of many forms of arthritis, exposes subchondral bone to create symptomatic joint pain. In addition to articular cartilage, cartilaginous tissues remain in the adult at several body sites such as the ears and nose, areas that are often subject to reconstructive surgery.

[0004] Articular cartilage has a limited response to injury in the adult mainly due to a lack of vascularisation and the presence of a dense proteoglycan rich extracellular matrix. The former inhibits the appearance of inflammatory and pluripotential repair cells, while the latter emprisons resident chondrocytes in a matrix non-conducive to migration. However, lesions that penetrate the subchondral bone create a conduit to the highly vascular bone allowing for the formation of a fibrin clot that traps cells of bone and marrow origin in the lesion leading to a granulation tissue. The deeper portions of the granulation tissue reconstitute the subchondral bone plate while the upper portion transforms into a fibrocartilagenous repair tissue. This tissue can temporarily possess the histological appearance of hyaline cartilage although not its mechanical properties and is therefore unable to withstand the local mechanical environment leading to the appearance of degeneration before the end of the first year post-injury. Thus the natural response to repair in adult articular cartilage is that partial thickness lesions have no repair response (other than cartilage flow and localized chondrocyte cloning) while full-thickness lesions with bone penetration display a limited and failed response. Age, however, is an important factor since full thickness lesions in immature articular cartilage heal better than in the adult, and superficial lacerations in fetal articular cartilage heal completely in one month without any involvement of vasculature or bone- derived cells.

[0005] Current clinical treatments for symptomatic cartilage defects involve techniques aimed at: 1) removing surface irregularities by shaving and debridement; 2) penetration of subchondral bone by drilling, fracturing or abrasion to augment the natural repair response described above (i.e. the family of bone-marrow stimulation techniques); 3) joint realignment or osteotomy to use remaining cartilage for articulation; 4) pharmacological modulation; 5) tissue transplantation; and 6) cell transplantation. Most of these methods have been shown to have some short term benefit in reducing symptoms (months to a few years), while none have been able to consistently demonstrate successful repair of articular lesions after the first few years. The bone marrow-stimulation techniques of shaving, debridement, drilling, fracturing and abrasion athroplasty permit temporary relief from symptoms but produce a sub-functional fibrocartilagenous tissue that can be readily degraded under normal daily load- bearing. In a 5-year follow-up, 10 out of 40 patients treated with microfracture were considered failures in need of total knee arthoplasty. [0006] Lesions in the articular cartilage layer can be resurfaced with repair tissue via surgical treatments that induce bleeding from subchondral bone (Marchand et al., 2009, Osteoarthritis and Cartilage, 17: 950-957; International application publication No. WO 08/064487; Hoemann et al., 2007, Osteoarthritis and Cartilage, 15: 78-89; and Chevrier et al., 2007, Osteoarthritis and Cartilage, 15: 316-327, the content of which are enclosed by reference). These surgical techniques are part of a family of methods called marrow stimulation therapy, where the surgeon debrides the damaged cartilage to remove glycosaminoglycan-containing tissue (non-calcified and calcified cartilage), then perforates holes into the highly vascularised subchondral bone with a drill or microfracture awl, or abrades the surface of the bone until punctuate bleeding is observed throughout the bed of the lesion. The ensuing repair response leads to the formation of a fibrous repair tissue (Hoemann et al., 2005, J Bone and Joint Surgery, 87A (12): 2671-2686) that can rapidly degrade under normal daily load-bearing. In a 5-year follow-up, 10 out of 40 patients treated with microfracture were considered failures in need of total knee arthoplasty.

[0007] Cartilage repair following marrow stimulation is initiated by bleeding and the formation of a blood clot. Coagulation is the biological initiator of spontaneous wound repair which is propagated by chemotaxis of neutrophils, macrophages, and connective tissue cells to the wound. Further attraction of blood vessels and stem cells to the wound can create a microenvironment in which tissues can be regenerated through specialized cell differentiation and deposition of an extracellular matrix that is mechanically functional.

[0008] To enhance the osteochondral repair response following marrow stimulation, a wound-stimulatory implant has been developed, consisting of an autologous, in situ solidifying scaffold-stabilized blood clot. The scaffold- stabilized clot is generated by mixing a cytocompatible polymer solution such as glycerol phosphate-buffered chitosan with unclotted whole blood (International application publication No. WO 02/000272, the content of which is enclosed by reference). Application of the implant to cartilage defects with surgically- generated holes in the subchondral bone (marrow stimulation) attracts neutrophils and macrophages, stimulates revascularization and active bone remodelling of the subchondral bone and calcified cartilage layer. These modified acute wound-repair responses are followed by the development of a more hyaline cartilage repair tissue compared to marrow stimulation alone, with greater levels of glycosaminoglycan. Relative to microfracture-only controls, microfracture defects treated with chitosan-glycerol phosphate (GP)/blood implant had a higher average percent fill with repair tissue compared to the original cartilage volume (52% treated vs 31 % control) and repair cartilage with significantly greater hyaline quality (86% vs 71 % control). In the best case repair, a zonal organization of the repair cartilage tissue that resembled normal articular cartilage was seen, suggesting that appositional processes active during normal organogenesis were stimulated by the chitosan-GP/blood implant.

[0009] The chitosan-GP/blood implant could be used to stimulate regeneration of a wide variety of damaged tissues, however the use of the implant is limited by the delivery method, which requires a horizontally-placed defect into which the liquid solution can be deposited and subsequently solidify.

[0010] The chitosan implant could be used to stimulate regeneration in patients up to 65 years old. However in a rabbit repair model with skeletally mature (7 to 13 months old) and skeletally aged (over 15 months old) animals, the therapeutic response to both drilling and drilling with chitosan-glycerol phosphate (GP)/blood implant was greatly attenuated in skeletally aged animals (Chen et al, Cartilage, e-pub ahead of print Oct 10, 2010, DOI: 10.1177/1947603510381096). These results are consistent with previous reports that older patients have an attenuated repair response to microfracture. The chitosan-GP/blood implant is thus known to be most effective in younger animals (i.e. 12 months old or less in rabbits). A chitosan implant formulation that leads to a robust repair response in aged subjects has not yet been identified.

[0011] It is also unknown whether glycerol phosphate is required for the therapeutic effect of the implant. Delivery of additional therapeutic factors could be used to promote the repair response, however it is currently uncertain whether simple mixture of therapeutics into a liquid chitosan formulation results in successful and local delivery of the therapeutic.

[0012] Chitosan-GP/blood implants combined with proper microfracture surgical technique can increase the generation of hyaline repair tissue compared to surgical microfracture technique alone. The implant must reside in situ, in order to exert a therapeutic effect on tissue repair. Liquid mixtures of chitosan-GP/blood cannot be successfully delivered to defects that are placed at an angle or upside-down, because the liquid implant must reside in the defect for at least 1 minute to be able to solidify in situ. Injection of the liquid mixture into bleeding osteochondral defects is an uncontrolled delivery method and does not guarantee implant residency. Injection of the liquid mixture below haemostatic defects is not feasible because the cavity will be already filled with a solid coagulum.

[0013] As lesions are frequently encountered in surgical arthroscopic treatments at an angle or upside down, it would be advantageous to have an implant that could be delivered to a surgical lesion irrespective of the position.

[0014] Treatment of a meniscal tear or uncontained bone fracture site may require a solid formulation that can be delivered in situ and be retained in the wound site.

[0015] It would thus be desirable to be provided with a composition and method for delivering therapeutic implants to subchondral defects, positioned at any angle, that subsequently elicit a therapeutic bone marrow repair responses such as subchondral angiogenesis and bone remodelling, activities previously associated with hyaline cartilage repair. It would also be desirable to identify a composition that elicits a greater quantity of cartilage repair tissue in aged subjects. It would also be desirable to demonstrate a method for local delivery of biological therapeutics to a wound site. SUMMARY

[0016] In accordance with the present disclosure, there is now provided a solidified composition for use in repairing tissue of a patient comprising a blood component, a salt and a polymer, the blood component, salt and polymer being mixed and solidified in a recipient before introduction in the patient for repairing the tissue.

[0017] The recipient can be made of glass or plastic.

[0018] In an embodiment, the polymer is a modified or natural polysaccharide, such as polysaccharide selected from the group consisting of chitosan, chitin, hyaluronan, glycosaminoglycan, chondroitin sulfate, keratan sulfate, dermatan sulfate, heparin, decorin, and heparin sulfate.

[0019] In another embodiment, the salt can be an organic or inorganic salt, such as sodium salt, chloride salt, potassium salt, calcium salt, magnesium salt, phosphate salt, sulfate salt or carboxylate salt; at least one of NaCI, KCI, CsCI, CaCI₂, CsF, KCI0₄ NaN0₃ or CaS0₄; or glycerol-phosphate.

[0020] In an embodiment, the composition has a pH between 6.0 and 7.8.

[0021] The chitosan can be 20% to 100% deacetylated with an average molecular weight ranging from 1 kDa to 10 MDa, or preferably having an average molecular weight ranging from 10 kDa to 150 kDa.

[0022] In a further embodiment, the blood component is selected from the group consisting of whole blood, processed blood, venous blood, arterial blood, blood from bone, blood from bone-marrow, bone marrow, umbilical cord blood, plasma, platelet-enriched plasma and placenta blood.

[0023] The blood component can also be selected from the group consisting of erythrocytes, leukocytes, monocytes, platelets, fibrinogen and thrombin, and further comprises platelet rich plasma free of erythrocytes.

[0024] In an embodiment, the composition is thermogelling. [0025] In an additional embodiment, the composition described herein comprises a clotting factor promoting thrombin generation.

[0026] The clotting factor can be selected from the group consisting of thrombin, factor Vila, tissue factor, factor XIII, factor Xllla, Factor IX, Factor Xla, Factor X, Factor Xa, Factor V, Factor Va, Factor VII, rVlla, fibrinogen, fibrin phospholipids, phosphatidyl serine, phosphatidyl choline, phosphatidyl inositol, phosphoryl choline, calcium, tissue factor-phospholipids, tissue factor ectodomain, tissue factor ectodomain-phospholipids, tissue factor ectodomain- phospholipids-rVlla, and tissue factor-phospholipids-rVI la.

[0027] In an additional embodiment, the composition described herein further comprises a Colony-stimulating factor (CSF), such as Granulocyte Macrophage Colony stimulating factor (GM-CSF) or Leukomax® or Leukine®, Granulocyte Colony stimulating factor (G-CSF) or Neupogen®, or Macrophage Colony Stimulating Factor (M-CSF).

[0028] In a preferred embodiment, the mixing ratio of clotting factor/composition is 1 :100 v/v; the clotting factor is thrombin at a concentration of 0.001 U/ml to 1000 U/ml; the clotting factor is tissue factor at a concentration of 0.1 pg/ml to 10 pg/ml; the clotting factor is rVlla at a concentration between 50 pg/ml to 500 pg/ml or the clotting factor is factor Xllla at a concentration of 0.01 U/ml to 100 U/ml.

[0029] In accordance with the present invention there is also provided the use of a solidified composition as defined herein for repairing tissue in a patient.

[0030] In an embodiment, the tissue is selected from the group consisting of cartilage, meniscus, ligament, tendon, bone, skin, cornea, periodontal tissues, abscesses, resected tumors, infarcted cardiac tissue, ischemic tissues and ulcers.

[0031] In another embodiment, the composition stimulates subchondral angiogenesis, monocyte/macrophage chemotaxis, osteoclast formation, bone remodeling or osteochondral repair. [0032] In an additional embodiment, the composition is a vehicle for further delivering a therapeutic substance, such as a polysaccharide, a polypeptide, a drug, a liposome, a DNA, a DNA-polymer complex, an antibody, a siRNA, an extracellular matrix fragment, a growth factor, a cytokine, a chemotactic factor, an osteoclast-promoting factor, a colony stimulating factor or an angiogenic factor.

[0033] In a further embodiment, the composition attracts osteoclasts to the subchondral bone plate when administered to the patient.

[0034] In a further embodiment, the composition comprises an acid such as a mineral acid or an organic acid.

[0035] The acid can be, but not restricted to, hydrochloric acid, lactic acid, acetic acid, citric acid, nitric acid, phosphoric acid, sulfuric acid, boric acid hydrofluoric acid or hydrobromic acid.

[0036] In accordance with the present disclosure, there is also provided a method for repair and/or regeneration of a tissue of a patient comprising administering a solid composition as defined herein into the tissue in need of repair and/or regeneration, wherein the composition when placed at the site in need of repair will adhere to the site in need of repair and reside in this site, to effect repair and/or regeneration of the tissue.

[0037] In accordance with the present disclosure, there is additionally provided a method of preparing a presolidified composition for use in repairing tissue of a patient comprising mixing a blood component, a salt and a polymer to form an homogenous composition as described herein; and solidifying the composition in a recipient before introduction of the composition in the patient for repairing the tissue.

[0038] In accordance to an embodiment, when the recipient is made of glass, the solidifying step requires incubation for 20 to 30 minutes at 37°C. [0039] In accordance to another embodiment, when the recipient is made of plastic, the composition further comprises the addition of a clotting factor prior to the solidifying step.

[0040] In a further embodiment, the composition is prepared 1 minute to 120 minutes prior to the introduction of the composition in the patient for repairing the tissue.

[0041] In another embodiment, the clotting factor is added to allow solidification of the composition within 5 minutes at room temperature or 37°C.

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Reference will now be made to the accompanying drawings, showing by way of illustration:

[0043] Fig. 1 illustrates presolidified implants formed in glass tubes with small inner diameter at 10 minutes at room temperature (A) of 30 minutes at 37°C (B).

[0044] Fig. 2 illustrates implants that can be generated in small-diameter glass tubes using chitosans with a wide range of molecular masses (A), different salts (B), and different acids (C).

[0045] Fig. 3A illustrates that chitosan-NaCI forms solid clots faster when mixed with whole blood than when chitosan-glycerol phosphate is mixed with whole blood. Fig. 3B illustrates that chitosan-NaCI forms solid clots faster when mixed with human whole blood than chitosan-glycerol phosphate, over a broad molecular weight range (chitosan with 80% DDA). Fig. 3C illustrates that leukocytes remain viable in chitosan-NaCI/blood clots solidified with and without a biologic and that the viable leukocytes release de novo chemotactic chemokines IL-8 and MCP-1.

[0046] Fig. 4 illustrates presolidified implants of 40 kDA chitosan-HCI- NaCI/Blood elasticity and deformation. [0047] Fig. 5 illustrates that presolidified implants are homogeneous interpenetrating networks, as shown by the uniform distribution of fluorescent RITC-chitosan in the clot on photographic representations at 1.25x magnitude (A-D) or 5x magnitude (F-H) of 10K-HCI-glycerol phosphate (GP) (A and E); 10K-lactate-GP (B and F); 40K-HCI-NaCI (C and G); and 150K-HCI-NaCI (D and H).

[0048] Fig. 6A illustrates presolidified implants that can be prepared in plastic devices with tissue factor showing the Microman® (a), the Microman® plastic tip (b) and the presolidified implant (c). Fig. 6B illustrates that implants can be aseptically solidified on plastic surfaces with Tissue Factor. Fig. 6C illustrates that implants can be solidified aseptically in glass tubes after incubating 30 minutes at 37°C.

[0049] Fig. 7 illustrates ex vivo delivery of presolidified implant (M100 Microman® with tissue factor) (A), and histological appearance in the saggital plane, after immunostaining with collagen type I or collagen type II, the arrow indicating the implant (B).

[0050] Fig. 8 illustrates photographic representations (A-B) of presolidified implants delivered in vivo in rabbit 1.5 mm osteochondral drill holes.

[0051] Fig. 9 illustrates presolidified implants with 3 formulations delivered in vivo in 2 distinct rabbit knees, more specifically of 3 drill holes before (A) and after inserting implants (10K, 40K, 150K; B); one distal 10K implant (C) or 3 implants (10K, 40K, 150K; D); and 2 drill holes before (E) and after inserting implants (10K+G-CSF, 40K+G-CSF; F).

[0052] Fig. 10 illustrates macroscopic in vivo retention (via fluorescent chitosan particles incorporated in each implant) and angiogenic response (via reddish-colored repair tissue after 3 weeks in vivo) of 3 presolidified implant formulations. Macroscopic images show red-colored treated repair tissue (A) and white-colored control repair tissue (C); fluorescent images of the defects show implant retention (B). [0053] Fig. 1 1A illustrates in vivo bone remodeling response (wider drill holes) to 3 presolidified implant formulations after 21 days (C), compared to 1 day (A) or 21 days in control defects (B) by micro-computed tomography scans of repaired distal femur bone. Figure 11 B illustrates the in vivo bone remodeling response and osteoclast formation elicited by 3 biodegradable implant formulations after 3 weeks.

[0054] Fig. 12 illustrates a graphic showing presolidified implants suppression of post-operative effusion in a bilateral rabbit model of osteochondral repair.

[0055] Fig. 13 illustrates that chitosan-NaCI/blood implant formulations degrade in situ with molecular weight-specific kinetics.

[0056] Fig. 14 illustrates that after 3 weeks of repair, implants elicited a more integrated granulation repair tissue, while controls formed a more GAG-positive repair tissue. After 3 weeks of repair, higher osteoclast recruitment in treated defects was associated with greater lateral integration of the repair tissue with native adjacent cartilage (Panels A-G). Implants delayed chondroinduction, which allows a longer time span for stem cell recruitment to the repair site by preventing early extracellular matrix deposition (panel H) Persistent chitosan particles at 3 weeks was associated with neutrophil necrosis (dark blue subchondral region "150kDa", panel D).

[0057] Fig. 15 illustrates that after 2.5 months of repair, significantly more in situ chondroinduction was obtained in drilled defects treated with 10K, 80%DDA chitosan implant in skeletally mature (12 months old) and skeletally aged animals (32 months old) compared to drill-only defects. Treated defects showed better lateral and basal integration. Untreated defects showed more chondrocyte cloning (C) and chondrocyte hypertrophy (H).

[0058] Fig. 16 illustrates evidence that 10K chitosan-NaCI/blood implants elicit significantly more in situ chondroinduction than drilling alone in skeletally mature and skeletally aged animals. In N=9 treated and N=9 drill-only defects, significantly more glycosaminoglycan-positive cartilage repair tissue was formed in treated drill holes after 2.5 months post-operative (roughly double the area in histological sections taken through the middle of the drill hole). The surface area of all Safranin 0+ repair tissue in the former drill hole area was quantified in N=9 different treated and control defects.

[0059] Fig. 17A and B illustrates Western Blot analysis showing that anionic cytokines can be reversibly immobilized on chitosan particles The formulation made by sequential mixing 0.4 mL of 2% w/v chitosan-HCI ~pH 5, 0.1 mL of 750 mM NaCI, 0.05 μ!_ of Neupogen® (G-CSF, pl=5.43, accession number P09919) and 1.5 mL recalcified human citrated plasma; Mix, place in glass vial at 37°C for 0 minutes (t=0) or 60 minutes (t=60). In control samples, no G-CSF was added. In another control sample, chitosan-NaCI was replaced by anion exchange resin AG10 particles in isotonic NaCI. Four volumes of ice-cold, neutral-buffered saline with protease inhibitors (quench buffer) were added to each sample. Resulting insolubles (including chitosan particles) were washed exhaustively in quench buffer, and proteins that remained bound to the pellet were eluted in 8 M urea and analyzed by Western blot with anti-human G-CSF antibody. The data show that G-CSF became bound to chitosan before coagulation and could be eluted from chitosan-NaCI particles before and after coagulation. (Top panel: lanes 1 : molecular weight; 2: purified G-CSF (100 ng); 3: 10 kDa pellet (no G-CSF added); 4: 40 kDa pellet (no G-CSF added); 5: anion exchange resin pellet (no G-CSF added); 6: 10 kDa + G-CSF; 7: 40 kDa + G-CSF; 8: anion exchange resin + G-CSF pellet; 9: 10 kDa + G-CSF (no plasma); and 10: plasma + G-CSF (pellet); Bottom panel: lanes 1 : molecular weight; 2: purified G-CSF (100 ng); 3: 10 kDa pellet (no G-CSF added); 4: 40 kDa pellet (no G-CSF added); 5: plasma clot pellet; lane 6: anion exchange resin pellet (no G-CSF added); 7: 10 kDa + G-CSF; 8: 40 kDa + G-CSF; 9: anion exchange resin + G-CSF pellet; and 10: plasma + G-CSF (pellet)).

[0060] Fig. 18A illustrates proof-of-concept of cytokine delivery in vivo, using a low molecular mass chitosan formulation (presolidified 10 kDa or 40 kDa 80% DDA chitosan-NaCI/blood). Histological scoring was carried out on repair tissue elicited by the various treatments. The most hyaline repair was obtained with 10 kDa chitosan. A worse repair was obtained with 10 kDa chitosan+G-CSF. The cartilage repair outcome was worse for 40 kDa compared to 10 kDa. The G- CSF implants had a distinct and worse repair than chitosan alone, which demonstrates that the cytokine was successfully delivered. Average histological scores (standard deviation) are shown (H=hyaline (3), FC= fibrocartilage (2), F=fibrous tissue (1), B/N=bone/no tissue (0)). The frequency of repair tissue morphology for each treatment is shown in the pie charts.

[0061] Fig. 18B is a graphical representation showing that G-CSF and GM- CSF were delivered locally to the defect and did not create systemic mobilization of neutrophils above what was seen using implant with chitosan- only. The factors were delivered as described in Fig. 18A.

[0062] Fig. 19 illustrates the delivery of presolidified implants independent of defect orientation (A: prior to defect creation; B: perpendicular defects; C: implants self-inserted holes; and D: size of osteochondral plugs removed by jamshidi needle).

[0063] Fig. 20 illustrates evidence of 1 day residency of presolidified implants in vivo in sheep medial femoral condyle jamshidi bone biopsy osteochondral defects, through the macroscopic fluorescent detection of fluorescently labeled chitosan particles of the same molecular mass and DDA level, co-delivered in the three different presolidified implant formulations.

[0064] Fig. 21 illustrates after 3 months of repair (sheep in vivo model), cartilage flow (white arrows) & chondro-induction (black arrows) were seen in 150 KDa implant treated defects.

[0065] Fig. 22 illustrates photographic representations of ex vivo testing demonstrating the requirements for presolidified implants self-insertion into osteochondral holes in any given orientation.

DETAILED DESCRIPTION

[0066] It is provided a method and formulation to generate a presolidified implant that can be inserted into a surgically prepared osteochondral defect. [0067] In accordance with the present description there is now provided a solidified composition for use in repairing tissue of a patient comprising a blood component, a salt and a polymer, the blood component, salt and polymer being mixed and solidified in a recipient before introduction, administration and/or use in the patient for repairing the tissue.

[0068] In accordance with the present description, there is provided the use of a solidified composition as defined herein for repairing tissue in a patient.

[0069] The tissue repaired can be selected from the group consisting of cartilage, meniscus, ligament, tendon, bone, skin, cornea, periodontal tissues, abscesses, resected tumors, infarcted cardiac tissue, ischemic tissues and ulcers.

[0070] The presolidified composition stimulates subchondral angiogenesis, monocyte/macrophage chemotaxis, osteoclast formation, bone remodeling or osteochondral repair.

[0071] In an additional embodiment, the composition is a vehicle for further delivering a therapeutic substance, such as a polysaccharide, a polypeptide, a drug, a liposome, a DNA, a DNA-polymer complex, an antibody, a siRNA, an extracellular matrix fragment, a growth factor, a cytokine, a chemotactic factor, an osteoclast-promoting factor, a colony stimulating factor or an angiogenic factor.

[0072] In another embodiment, the composition attracts osteoclasts to the subchondral bone plate when administered to the patient.

[0073] It is also provided herein a method for repair and/or regeneration of a tissue of a patient comprising administering a solid composition as defined herein into the tissue in need of repair and/or regeneration, wherein the composition when placed at the site in need of repair will adhere to the site in need of repair and reside in this site, to effect repair and/or regeneration of the tissue. [0074] There is additionally provided a method of preparing a presolidified composition for use in repairing tissue of a patient comprising mixing a blood component, a salt and a polymer to form an homogenous composition as described herein; and solidifying the composition in a recipient before introduction of the composition in the patient for repairing the tissue.

[0075] Chitosan, which primarily results from the alkaline deacetylation of chitin, a natural component of shrimp and crab shells, is a family of linear polysaccharides that contains 1-4 linked glucosamine (predominantly) and N- acetyl-glucosamine monomers. Chitosan and its amino-substituted derivatives are pH-dependent, bioerodible and biocompatible cationic polymers that have been used in the biomedical industry for wound healing and bone induction (Shigemasa and Minami, 1996, Biotechnol Genet Eng Rev, 13:383-420). Chitosan is termed a mucoadhesive polymer since it adheres to the mucus layer of the gastrointestinal epithelia via ionic and hydrophobic interactions, thereby facilitating per oral drug delivery. Biodegradability of chitosan occurs via its susceptibility to enzymatic cleavage by a broad array of endogenous enzymes including chitinases, lysozymes, cellulases and lipases (Shigemasa and Minami, 1996, supra).

[0076] The properties of chitosan that are most commonly cited as beneficial for the wound repair process are its biodegradability, adhesiveness, prevention of dehydration and as a barrier to bacterial invasion. Other properties that have also been claimed are its cell activating and chemotractant nature (Shigemasa, and Minami, 1996, supra), its hemostatic activity (US Patent No. 4,532,134) and an apparent ability to limit fibroplasia and scarring by promoting a looser type of granulation tissue.

[0077] Chitosan has been proposed in various formulations, alone and with other components, to stimulate repair of dermal, corneal and hard tissues in a number of reports and inventions.

[0078] In cartilage repair models involving live animals and in clinical applications with human patients, the chitosan-glycerol phosphate (GP)/blood implant reproducibly solidifies in situ within 5 to 10 minutes. In situ delivery entails applying the liquid mixture onto the lesion followed by implant solidification in the lesion. An alternative approach would be to generate presolidified, cytocompatible, hybrid chitosan blood clots, that can be inserted into surgically-generated marrow-stimulation holes. Ideally, the implant could be passively inserted into marrow-stimulated subchondral bone channels irrespective of the position of the channel (horizontal, vertical, and upside down). The presolidified implant formulation should generate an equal or improved wound-repair response, compared to the chitosan-GP/blood implant.

[0079] The present disclosure consists in mixing an isotonic and near-neutral chitosan solution with blood, such as whole blood, that is solidified aseptically in a small-diameter recipient, cylinder or tube made of glass or of plastic. Solidification in plastic cylinders or on plastic surfaces requires further addition of a clotting factor such as rFVIIa or Tissue Factor to the mixture, while solidification in glass cylinders requires incubation for 20 to 30 minutes at 37°C. Although clotting factors can be used to accelerate the in situ solidification of previously known liquid chitosan-GP/blood mixtures, the implants still require at least 1 minute to solidify, which prevents loading and solidification in defects that are not horizontally positioned (International application publication No. WO 08/064487). Consequently, in the present formulation, blood is used to deliver and retain bioactive biodegradable (low molecular mass) chitosan particles to the repair site. The present formulation can also be used to deliver and retain active biologies co-delivered by chitosan particles at the repair site.

[0080] Furthermore, the methods and compositions described herein allows for local delivery of ectopic factors in the implant, and also more controlled delivery of the implant itself, as opposed to a liquid in s/¾/-solidifying formulation that can spill to non-target tissues at delivery. Therefore the current disclosure allows for better control over delivery and dosage, compared to prior art.

[0081] The solid hybrid clot implant disclosed herein is readily delivered to a 1.5 mm to 2 mm wide and 2 mm to 8 mm deep osteochondral defect that is placed in a horizontal, vertical, or upside-down position, by press-fitting, or by passive capillary action when the implant diameter is less than the osteochondral hole diameter, and the ostechondral defect surfaces are humidified with a balanced salt solution.

[0082] Solidified implants reside in osteochondral defects placed in live animal knee joints (rabbit and sheep), and promote local therapeutic wound- repair processes including angiogenesis, subchondral bone remodelling, and hyaline articular cartilage repair. It is disclosed herein a solidified chitosan-blood implant that is easily extruded from a sterile delivery device or solidified on a flat surface and remains intact during transplantation to a surgically prepared osteochondral drill hole. The chitosan particles attract osteoclasts to the subchondral bone plate. It is also disclosed the use of glass and plastic casting devices for pre-solidifying a chitosan-blood implant, and the practical aspects of in vivo delivery, retention and wound-repair responses of implants with distinct chitosan formulations, including a wide range of chitosan molecular masses (for example 10 kDa to 150 kDa) and deacetylation levels (60% to 100% DDA).

[0083] The term "repair" when applied to cartilage and other tissues is intended to mean without limitation repair, regeneration, reconstruction, reconstitution or bulking of cartilage or tissues.

[0084] The term "blood" is intended to mean whole blood, processed blood, venous blood, arterial blood, blood from bone-marrow, umbilical cord blood and placenta blood. It may be enriched in platelets.

[0085] The term "blood component" is intended to mean erythrocytes, leukocytes, monocytes, platelets, fibrinogen, and thrombin. It may further comprise platelet rich plasma free of erythrocytes. In another embodiment, blood component is intended to mean any component of the blood retaining clotting properties.

[0086] The term "biocompatible polymer" is intended to mean a polymer that can be contacted with a tissue, without altering the tissue viability and that is tolerated or accepted by the tissue or the organism. [0087] The term "patient" is intended to mean a human or an animal.

[0088] The term "solidification" or "presolidification" is intended to mean the loss of the liquid state to the benefit of the solid state.

[0089] The term "thermogelling" is intended to mean the characteristic of a polymer which becomes non-liquid at a certain temperature.

[0090] The term "clotting" is intended to mean a type of solidification involving formation of a blood clot.

[0091] The term "Colony-stimulating factors" or "CSFs" are intended to mean secreted glycoproteins which bind to receptor proteins on the surfaces of bone marrow stem cells and thereby activate intracellular signaling pathways which can cause the cells to migrate, proliferate or differentiate into a specific kind of cell (ie. mesenchymal stem cells which usually differentiate into chondrocytes, osteoblasts, or adipocytes depending on the local environment; or hematopoietic stem cells which usually differentiate into white blood cells, for red blood cell formation see erythropoietin). In addition CSFs can stimulate bone marrow macrophages to differentiate into osteoclasts.

[0092] The expression "therapeutic substance" is intended to refer to the property of any substance to have beneficial or therapeutic effect on the patient administered with the substance. Such therapeutic substance can be, but not limited to, a polysaccharide, a polypeptide, a drug, a liposome, a DNA, DNA- polymer complex, an antibody, a siRNA, an extracellular matrix fragment, a growth factor, a chemotactic factor, a colony stimulating factor, a neutrophil chemotactic factor, a stem cell chemotactic factor, a monocyte chemotactic factor, an osteoclast-forming factor, and an angiogenic factor.

[0093] The present disclosure will be more readily understood by referring to the following examples which are given to illustrate embodiments rather than to limit its scope. EXAMPLE I

Presolidified implants can be generated by mixing isotonic chitosan solutions whole blood and 30 minutes incubation at 37°C in glass tubes.

[0094] Chitosan-GP/blood mixtures solidify through coagulation and activation of the clotting cascade, and glass presents a negatively charged surface that can activate the FXII-dependent contact pathway in whole blood and chitosan-GP/blood mixtures. Therefore it was feasible that chitosan- GP/blood mixtures could be made to solidify in glass tubes. 2% w/v chitosan with 80% DDA and 150 kDa molecular mass was dissolved in HCI at pH 5.6, then 400 μΙ of chitosan was combined with 50 μΙ of 500 mM disodium β-glycerol phosphate/50 mM HCI pH 7.2 in a 2 ml cryovial with 3 stainless steel 0.39g beads. 1.5 ml of fresh nonactivated human whole blood was added to the vial, shaken for 10 seconds, and the mixture drawn into glass tubes with a 2 mm or 2.5 mm inner diameter and plastic 1.0 ml syringes.

[0095] After 30 minutes incubation at 37°C the mixture failed to solidify in a plastic syringe while a solid and elastic implant formed in glass 2.0 mm and 2.5 mm tubes (see Figs. 1 and 2). This experiment demonstrated the feasibility of producing a presolidified implant with an isotonic chitosan solution and whole blood.

[0096] It was previously established that chitosan-GP/blood mixtures can be formed using chitosans with medium to high viscosity dissolved in HCI and made isotonic with disodium β-glycerol phosphate. However it was not know whether chitosan with very low molecular mass, or dissolved in different acids, or combined with other salts, could form a hybrid clot implant. Therefore distinct formulations were tested for the capacity to form presolidified implants. Sterile 2% w/v chitosan solutions were made with 80% degree of deacetylation (DDA) chitosans with 10 kDa (10K), 40 kDa (40K) or 150 kDa (150K) molecular mass chitosan by dissolving the chitosan in 78 mM acid (HCI or lactic acid, to achieve 80% chitosan theoretical protonation, pH 5.6), and autoclaving. The chitosan solutions were further made isotonic by combining with a salt additive (sodium chloride or disodium glycerol phosphate, GP). Fluorescent rhodamine- isothiocyanate (RITC)-chitosan tracer (0.5% to 1.0% mol/mol RITC/chitosan) of identical mass and DDA level was added to each formulation. The formulations were then mixed aseptically with whole rabbit blood in 2-ml flat-bottom cryovials with 3 stainless steel 0.39 g beads by vigorous shaking for 10 seconds. Chitosan-blood mixtures were made in a 1 :3 or 1 :6 ratio of chitosan:blood ratio according to the formulations in Table 1 , and drawn into glass tubes with a 2.5 mm inner diameter. The samples were incubated at 37°C for 30 minutes, extruded by pushing the implant out of the glass tubing with a thin fitted wire, and each implant was submitted to tests for elastic strength, and inspected for serum extrusion, clot retraction, and homogeneity using an inverted fluorescent microscope.

Table 1

Formulations of chitosan:blood at different ratios

[0097] Chitosan-NaCI forms solid clots faster when mixed with whole blood than chitosan-B-glycerol phosphate. A formulation was sequentially mixed as follow: 0.4 mL 2% W/V chitosan-HCL (10 kDa and 80% DDA for chitosan), 0.1 mL 750 mM NaCI or 0.1 mL 500 mM disodium beta-glycerol phosphate-HCL pH7.2, and 1.5 mL whole human blood. Chitosan-salt was mixed at a 1 :3 or 1 :6 ratio with human whole blood and the clotting time was measured using thromboelastography. It was seen that low molecular mass chitosan coagulates more rapidly with human blood using NaCI instead of glycerol phosphate (GP) to attain physiologic osmolality. Chitosan-NaCI forms solid clots faster when mixed with whole blood than when chitosan-glycerol phosphate is mixed with whole blood (see Fig. 3A). Chitosan-NaCI forms solid clots faster when mixed with human whole blood than chitosan-glycerol phosphate, over a broad molecular weight range (chitosan with 80% DDA; Fig. 3B).

[0098] Chitosan-NaCI (containing 80%DDA chitosan, or chi) was mixed at a 1 :6 v/v ratio with human whole blood, clotted in sterile glass tubes, incubated for 4 hours at 37°C, and the serum analyzed for release of chemotactic factors. One sample per group was generated and it was read in duplicate wells with a Bioplex Bioanalyser. 4 samples were analyzed): WB: 1.5 mL whole blood + 220 μΙ 150 mM NaCI, 20 min at 37°C; 10 kDa chi: 200 μΙ 10 kDa chitosan-HCL + 20 μΙ 1500 mM NaCI + 1.5 mL whole blood, 4 hours at 37 °C; 40 kDa chi: : 200 μΙ 40 kDa chitosan-HCL + 20 μΙ 1500 mM NaCI + 1.5 mL whole blood, 4 hours at 37°C; and 10 kDa chi + G-CSF: same as 10 kDa chi + 80 μΙ Neupogen® (300 μg/mL G-CSF), 4 hours at 37°C. As seen in Fig. 3C, leukocytes remain viable in chitosan-NaCI/blood clots solidified with and without a biologic and the viable leukocytes release de novo chemotactic chemokines IL-8 and MCP-1.

[0099] Presolidified implants from all formulations tested retained a cylindrical shape after extrusion from the glass tubes, lost a small amount of serum, and were elastic and could be stretched with forceps to 120% to 200% of the initial length (Fig. 4). All implants generated homogeneous hybrid chitosan-blood implants (Fig. 5). To summarize, it is showed that presolidified implants could be formed with a variety of isotonic chitosan solutions of distinct formulation, when combined with whole blood at a 1 :3 or 1 :6 ratio.

EXAMPLE II

Presolidified implants made in plastic devices with clotting factor, and subsequently delivered to an ex vivo osteochondral defect.

[00100] The aim of this experiment was to optimize methods that generated a presolidified implant that could be inserted into a 1.5 mm diameter osteochondral drill hole generated in an ex vivo rabbit femur. In a first test, implants were generated with 10K-GP at a 1 :3 ratio with human whole blood, with or without 200 nM rFVIIa in 0.5 mm plastic tuberculin syringes, and incubated at room temperature or 37°C for 30 or 120 minutes. This experiment showed that implants generated in plastic 0.5 ml syringes required rVlla and a 37°C incubation temperature to solidify after 30 minutes. However the resulting solid implants were mechanically weak and too large in diameter to permit delivery to a 1.5 mm ex vivo osteochondral drill hole.

[00101] In a second test, implants were prepared in plastic Microman® tips with the tapered tip cut off (M100). 30 μΙ of chitosan 10-kDa-HCI-NaCI was mixed in 1 :3 ratio with whole rabbit blood and drawn into the plastic tip. Other chitosan-blood mixtures were drawn into the plastic tip, and subsequently exposed to Thrombin (6 U/ml or 100 U/ml) or Tissue Factor (undiluted Innovin®, 500 pM Tissue Factor) by back-screwing the pipet in order to draw 1 μΙ or 5 μΙ of clotting factor into the end of the pipet tip (Figs. 6Aa and b). The implants were allowed to solidify for 5 minutes at room temperature. Implants were shown to be aseptically solidified on plastic surfaces with Tissue Factor (Fig. 6B), in glass tubes after incubation during 30 minutes at 37°C.

[00102] Implants failed to solidify without or with addition of 1 μΙ clotting factor, or with addition of 5 μΙ Thrombin. However 5 μΙ of Tissue Factor induced solidification of 15 μΙ to 30 μΙ of the chitosan-blood mixture in plastic M100 tips, after 5 minutes at room temperature (Fig. 6Ac). This experiment demonstrated that presolidified implants can be formed and extruded from cylindrical plastic casting devices with the aid of Tissue Factor. Implants formed in M100 plastic tips with Tissue Factor were press-fit into 1.5 mm diameter drill holes generated in ex vivo rabbit femurs (for example, proximal hole in Fig. 7A), where they filled the bone defect (Fig. 7B). EXAMPLE III

Presolidified implants generated with or without a biologically active factor, delivered and retained in osteochondral defects in vivo, exerting a therapeutic effect on wound repair in skeletally aged animals.

[00103] The aim of this experiment was to test implant delivery, retention and biological activity in vivo. Feasibility of incorporating bioactive cytokines in the Presolidified implant was also tested. Implants were generated in plastic Microman® tips (condition 1) or glass tubes with an inner diameter of 2 mm (conditions 2 to 5). The formulations are listed in Table 2. In Group 1 , N=5 rabbits received small bilateral arthrotomies to create in each knee trochlea, three 1.4 mm diameter osteochondral drill holes. In the left knee, each drill hole was filled with a pre-solidified chitosan-blood implant solidified using Tissue Factor (Figs. 8 and 9), while the right knee control defects were treated with Tissue Factor only, or left untreated. N=1 rabbit was assigned to a 1-day repair period and N=4 rabbits were assigned to the 3-week repair group. The residency at surgery, macroscopic appearance and retention of the fluorescent implants after 1 day, or 21 days in vivo is shown in Fig. 10.

Table 2

Formulation of presolidified implants generated with or without a biologically active factor

^* G-CSF: Granulocyte Colony Stimulating Factor, Neupogen®, 300 g/ml clinical preparation in balanced salt solution;

^** GM-CSF: Granulocyte-Macrophage Colony Stimulating Factor, recombinant human, 200 pg/ml preparation in phosphate-buffere saline (PBS). [00104] These data showed that the presolidified implants (150K, 40K, and 10K) resided in the defects and elicited an angiogenic repair tissue after 21 days of repair. Micro-computed tomography (Micro-CT) of fixed femurs was performed using a SkyScan instrument at 12 μηη resolution. These scans revealed at Day 1 that there was only minor variation in acute drill hole depth and diameter. In N=4 rabbits with three treated drill holes after 21 days in vivo, Micro-CT scans showed that all 3 presolidified implant formulations elicited bone remodelling of the microdrill holes during 21 days of repair, as shown by a widening or "tear-shape" of the drill hole, compared to untreated drill holes that had straight side-walls (Fig. 1 1A). Tartrate-Resistant Acid Phosphatase (TRAP) enzymatic staining for osteoclasts showed that implants elicited osteoclasts to the subchondral bone plate (Fig. 1 1 B), promoted adhesion of the repair tissue to adjacent cartilage (Fig. 14) and elicited more cartilage repair tissue compared to drill-only in both skeletally mature and skeletally aged animals (Figs. 15 and 16). Post-operative knee effusion was suppressed by implant treatment as measured in a group of N=4 rabbits over a period of 14 days by visual inspection (Fig. 12). In these 4 rabbits, bilateral defects were treated or not with presolidified implants as shown in Fig. 8 (control: 2 drill holes no implant; treated: 2 drill holes filled with 10K-HCI-NaCI-RITC-chitosan/blood and 40K- HCI-NaCI-RITC-chitosan/blood). Effusion scores were generated on a scale of 0 to 4, where 0 was no effusion, 1 was slight effusion, 2 was clear effusion or swelling, 3 was a lump, and 4 was a very large lump (over 1 cm diameter) at the surgical or para-surgical site.

[00105] This evaluation demonstrated that presolidified implants could suppress post-operative effusion (Fig. 12), potentially by inhibiting postoperative in-joint bleeding.

[00106] All formulations used 80% DDA chitosan, after 3 weeks of repair in a rabbit in vivo model, 10 kDa chitosan implants are cleared more rapidly that 40 kDa and 150 kDa chitosan implants, according to residual fluorescence after 3 weeks of repair (Fig. 13). [00107] To prove that cytokines can be reversibly immobilized on chitosan particles, the following formulation was made by sequential mixing (Table 3).

Table 3

Formulations tested

[00108] These formulations were mixed, placed in glass vials at 37°C for 0 minutes (t=0) or 60 minutes (t=60). In control samples, no G-CSF was added. In another control sample, chitosan-NaCI was replaced by anion exchange resin AG-1X8 particles in isotonic NaCI. Four volumes of ice-cold, neutral-buffered saline with protease inhibitors (quench buffer) were added to each sample. Resulting insolubles (including chitosan particles) were washed exhaustively in quench buffer, and proteins that remained bound to the pellet were eluted in 8M urea and analyzed by Western blot with anti-human a G-CSF antibody.

[00109] Fig. 17 shows that G-CSF became bound to chitosan before coagulation and could be eluted from chitosan-NaCI particles before and after coagulation with urea. This experiment shows that 10K and 40K implants are potent scaffolds that link G-CSF non-covalently and deliver the cytokine locally when implanted in a defect needing repair.

[00110] As a proof-of-concept for cytokine delivery in vivo, the following low molecular mass chitosan formulations were made (Table 4). Table 4

Low molecular mass chitosan formulations

[00111] The implants were formed in a sterile glass tube for 20 minutes at 37°C, extruded, cut to size, then inserted into a 1.5 mm diameter, 2 mm deep drill hole in a live rabbit femoral trochlea, in skeletally mature rabbits (12 or 32 months old). After 2.5 months of repair, defects were decalcified, histoprocessed in OCT, and cryosections stained with Safranin O for glycosaminoglycan. Histological scoring was carried out on repair tissue elicited by the various treatments. The most hyaline repair was obtained with 10 kDa chitosan. A worse repair was obtained with 10 kDa chitosan+G-CSF. These data demonstrate that ultralow molecular mass chitosan fragments have a therapeutic effect on cartilage repair (Fig. 18A). The data also demonstrate that G-CSF was delivered to the defect via in situ delivered chitosan particles, because the repair tissue was altered by addition of G-CSF. Replacement of G- CSF with any of a variety of anionic therapeutic factor(s) would be a natural extension of these enabling data.

[00112] Fig. 18B proves that G-CSF and GM-CSF were delivered locally to the defect and did not create systemic mobilization of neutrophils above what was seen using implant with chitosan-only. The factors were delivered as described previously. The data show the locally delivered G-CSF and GM-CSF (using the 10K chitosan-NaCI/blood implant) did not have systemic effects. Typically these factors are used in the clinic (injected subcutaneously) to mobilize neutrophils in patients, for example following chemotherapy. Consequently, the methods and compositions described herein allows for local delivery of ectopic factors in the implant, and also more controlled delivery of the implant itself, as opposed to a liquid in s/fu-solidifying formulation that can spill to non-target tissues at delivery. Therefore the current disclosure allows for better control over delivery and dosage, compared to prior art.

EXAMPLE IV

Presolidified implants generated aseptically in glass tubes and delivered to a horizontal, vertical, or upside-down osteochondral defect.

[00113] The aim of this experiment was to demonstrate clinical feasibility of using presolidified implants to stimulate osteochondral repair, using a mature sheep model. An arthrotomy and a 2 mm jamshidi bone biopsy needle were used to generate six 2 to 8 mm deep holes in the medial femoral condyle. The cartilage surfaces were kept humid with balanced salt solution.

[00114] Presolidified implants were generated with three distinct formulations identical to condition 4 in Table 1 , using fresh sheep whole blood and glass casting tubes with 2.0 mm inner diameter (Fig. 6C). Small 2 to 3 mm length implants were trimmed using a scalpel blade. Upon holding the presolidified implant next to the jamshidi hole opening, it was discovered that the implants could self-insert into the holes by an unknown mechanism (Fig. 19). The implants self-inserted into holes that were vertically positioned, or facing the floor (upside-down, see arrow, Fig. 19C). After 1 day of residency in vivo with unlimited weight-bearing, N=1 sheep was sacrificed and the condyle inspected by inverted fluorescence microscopy. Most of the presolidified implants resided in the osteochondral holes after 1 day in vivo (Fig. 20). After 2.5 months in vivo, the 150 kDa chitosan-NaCI/blood implant promoted the formation of cartilage repair tissue (Fig. 21). [00115] In a second ex vivo assay, the mechanism of self-inserting presolidified implants was investigated. Using an ex vivo pig joint, a 2 mm biopsy tool was used to punch 12 circular cartilage biopsies to debride the cartilage into the calcified layer. 9 holes were made 3 mm deep with a 2 mm inner diameter jamshidi bone biopsy needle, and 3 holes were made with a 1.4 mm drill bit. The holes were cleaned with Ringer's Lactated Saline (RLS) and suctioned dry with a 20g needle. The joint was wrapped in RLS-soaked gauze for 1 hour at 37°C to warm the explants. Presolidified implants were then made according to Table 5, with fresh unmodified rabbit whole blood.

Table 5

Mini kit preparation

[00116] Fresh rabbit blood was also collected and used to fill a row of 3 holes (holes 2, 5, and 8), then after 5 minutes of incubation the liquid blood was removed leaving a blood coating in these bone holes (Fig. 22). The explant was kept at 37°C until the presolidified implants were finished incubating at 37°C. Three holes (holes 3, 6, and 9) were rinsed with 0.9% saline (isotonic saline) while holes 1 , 4, and 7 were suctioned dry. Presolidified implants were trimmed with a razor blade to 2 mm in length, then held next to the opening of each hole. The self-insertion of the implant into the hole was documented as shown in Fig. 22. Results showed that only holes humidified with balanced salt solution permitted the implant to self-insert in the hole. Implants did not self-insert into dry holes or holes lined with blood that was viscous (see Table 6). Table 6

Presolidified implants self-inserted to the bottom

of ex vivo osteochondral defects.

Scoring System:

Yes: the implant spontaneously glided to the bottom of the hole

No: the implant stayed atthe top of the hole, or didn't go into the hole unless press-fit.

[00117] These results were consistent with a mechanism by which capillary action drew the implant into the hole. Moreover, implants did not self-insert into holes that were smaller in diameter than the implant diameter because the air was trapped underneath the implant and not allowed to escape, thereby blocking capillary action. These data demonstrate that presolidified implants can be loaded in defects in various orientations including upside down, provided the implant diameter is smaller than the hole and the hole is humidified with a balanced salt solution. It is encompassed herein that plasma or platelet- enriched plasma could be substituted for whole blood, and that presolidified implants could be generated with whole blood mixed with any therapeutic factor that is compatible with blood coagulation. It is equally clear that extrusion of the presolidified implant could be performed directly into the wound cavity, provided the appropriate device or tools were available.

[00118] While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modifications and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as follows in the scope of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A presolidified composition for use in repairing tissue of a patient comprising a blood component, a salt and a polymer, said blood component, salt and polymer being mixed and solidified in a recipient before administration to the patient for repairing the tissue.

2. The composition of claim 1 , wherein the recipient is made of glass or plastic.

3. The composition of claim 1 or 2 wherein the polymer is a modified or natural polysaccharide.

4. The composition of claim 3, wherein the polysaccharide is selected from the group consisting of chitosan, chitin, hyaluronan, glycosaminoglycan, chondroitin sulfate, keratan sulfate, dermatan sulfate, heparin, and heparin sulfate.

5. The composition of any one of claims 1-4, wherein the salt is an organic or inorganic salt.

6. The composition of claim 5, wherein the inorganic salt is sodium salt, chloride salt, potassium salt, calcium salt, magnesium salt, phosphate salt, sulfate salt or carboxylate salt.

7. The composition of claim 6, wherein the salt is at least one of NaCI, KCI, CsCI, CaCI₂, CsF, KCI0₄ NaN0₃ or CaS0₄.

8. The composition of any one of claims 1-7, further comprising a mineral acid or an organic acid.

9. The composition of claim 8, wherein said acid is hydrochloric acid, lactic acid, acetic acid, citric acid, nitric acid, phosphoric acid, sulfuric acid, boric acid hydrofluoric acid or hydrobromic acid.

10. The composition of claim 5, wherein the organic salt is glycerol- phosphate.

11. The composition of any one of claims 1-10, wherein the composition has a pH between 6.0 and 7.8.

12. The composition of claim 4, wherein the chitosan is 60% to 100% deacetylated with an average molecular weight ranging from 1 kDa to 10 MDa.

13. The composition of claim 12, wherein the chitosan has an average molecular weight ranging from 10 kDa to 150 kDa.

14. The composition of any one of claims 1-13, wherein the blood component is selected from the group consisting of whole blood, processed blood, venous blood, arterial blood, blood from bone, blood from bone-marrow, bone marrow, umbilical cord blood, plasma, citrated plasma, platelet-enriched plasma and placenta blood.

15. The composition of claim 14, wherein the blood component is selected from the group consisting of erythrocytes, leukocytes, monocytes, platelets, fibrinogen and thrombin.

16. The composition of claim 14, wherein the blood component further comprises platelet rich plasma free of erythrocytes.

17. The composition of any one of claims 1-16, wherein the composition is thermogelling.

18. The composition of nay one of claims 1-17, further comprising a clotting factor promoting thrombin generation.

19. The composition of claim 18, wherein said clotting factor is selected from the group consisting of thrombin, factor Vila, tissue factor, factor XIII, factor Xllla, Factor IX, Factor XIa, Factor X, Factor Xa, Factor V, Factor Va, Factor VII, rVlla, fibrinogen, fibrin phospholipids, phosphatidyl serine, phosphatidyl choline, phosphatidyl inositol, phosphoryl choline, calcium, tissue factor-phospholipids, tissue factor ectodomain, tissue factor ectodomain-phospholipids, tissue factor ectodomain-phospholipids-rVlla, and tissue factor-phospholipids-rVlla.

20. The composition of any one of claims 1- 9, further comprising a Colony- stimulating factor (CSF).

21. The composition of claim 20, wherein said CSF is selected from the group consisting of Granulocyte Colony stimulating factor (G-CSF), Granulocyte Macrophage Colony stimulating factor (GM-CSF), and Macrophage Colony stimulating factor (M-CSF).

22. The composition of claim 18 or 19, wherein the mixing ratio of clotting factor/composition is 1 :100 v/v.

23. The composition of claim 19, wherein the clotting factor is thrombin at a concentration of 0.001 U/ml to 1000 U/ml.

24. The composition of claim 19, wherein the clotting factor is tissue factor at a concentration of 0.1 pg/ml to 10 pg/ml.

25. The composition of claim 19, wherein the clotting factor is rVlla at a concentration between 50 pg/ml to 500 pg/ml.

26. The composition of claim 19, wherein the clotting factor is factor Xllla at a concentration of 0.01 U/ml to 100 U/ml.

27. The composition of any one of claims 1-26, wherein the composition further comprises a bioactive cytokine.

28. The composition of any one of claims 1-27, wherein the composition attracts osteoclasts to the subchondral bone plate when administered to the patient.

29. Use of a presolidified composition as defined in any one of claims 1-28 for repairing tissue in a patient.

30. The use of claim 29, wherein the tissue is selected from the group consisting of cartilage, meniscus, ligament, tendon, bone, skin, cornea, periodontal tissues, abscesses, resected tumors and ulcers.

31. The use of claim 29 or 30, wherein said composition stimulates subchondral angiogenesis, bone remodeling or osteochondral repair.

32. Use of a presolidified composition as defined in any one of claims 1-28 for delivering a therapeutic substance in a patient.

33. The use of claim 32, wherein said therapeutic substance is a polysaccharide, a polypeptide, a drug, a liposome, a DNA, DNA-polymer complex, an antibody, a siRNA, an extracellular matrix fragment, a growth factor, a chemotactic factor, an osteoclast-promoting factor, a cytokine, a colony stimulating factor and/or an angiogenic factor.

34. A method for repair and/or regeneration of a tissue of a patient comprising administering a presolidified composition as defined in any one of claims 1-28 into said tissue in need of repair and/or regeneration, wherein said composition when placed at the site in need of repair will adhere to the site in need of repair to effect repair and/or regeneration of the tissue.

35. The method of claim 34, wherein the tissue is selected from the group consisting of cartilage, meniscus, ligament, tendon, bone, skin, cornea, periodontal tissues, abscesses, resected tumors and ulcers.

36. The method of claim 34 or 35, wherein said composition stimulates subchondral angiogenesis, bone remodeling or osteochondral repair.

37. A method for delivering a therapeutic substance in a patient comprising administering a solidified composition as defined in any one of claims 1- 28 admixed with the therapeutic substance into said patient.

38. The method of claim 37, wherein said therapeutic substance is a polysaccharide, a polypeptide, a drug, a liposome, a DNA, a DNA- polymer complex, an antibody, a siRNA, an extracellular matrix fragment, a growth factor, a chemotactic factor, a cytokine, a colony stimulating factor and/or an angiogenic factor.

39. A method of preparing a presolidified composition for use in repairing tissue of a patient comprising: a) mixing a blood component, a salt and a polymer to form an homogenous composition; and b) solidifying the composition in a recipient before introduction of the composition in the patient for repairing the tissue.

40. The method of claim 39, wherein the recipient is made of glass or plastic.

41. The method 40, wherein the recipient is made of glass and the solidifying step requires incubation for 20 to 30 minutes at 37°C.

42. The method of claim 41 , wherein the recipient is made of plastic and the composition further comprises the addition of a clotting factor prior to the solidifying step.

43. The method of claim 42, wherein said clotting factor is selected from the group consisting of thrombin, factor Vila, tissue factor, factor XIII, factor Xllla, Factor IX, Factor Xla, Factor X, Factor Xa, Factor V, Factor Va, Factor VII, rVlla, fibrinogen, fibrin phospholipids, phosphatidyl serine, phosphatidyl choline, phosphatidyl inositol, phosphoryl choline, calcium, tissue factor-phospholipids, tissue factor ectodomain, tissue factor ectodomain-phospholipids, tissue factor ectodomain-phospholipids-rVlla, and tissue factor-phospholipids-rVlla.

44. The method of any one of claims 39-43, wherein the polymer is a modified or natural polysaccharide.

45. The method of claim 44, wherein the polysaccharide is selected from the group consisting of chitosan, chitin, hyaluronan, glycosaminoglycan, chondroitin sulfate, keratan sulfate, dermatan sulfate, heparin, and heparin sulfate.

46. The method of any one of claims 39-45, wherein the salt is an organic or inorganic salt.

47. The method of claim 46, wherein the inorganic salt is sodium salt, chloride salt, potassium salt, calcium salt, magnesium salt, phosphate salt, sulfate salt or carboxylate salt.

48. The method of claim 47, wherein the salt is at least one of NaCI, KCI, CsCI, CaCI₂, CsF, KCI0₄ NaN0₃ or CaS0₄.

49. The method of claim 48, wherein the organic salt is glycerol-phosphate.

50. The method of any one of claims 39-49, wherein the composition is prepared 5 minutes to 120 minutes prior to the introduction of the composition in the patient for repairing the tissue.

51. The method of claim 42 or 43, wherein the clotting factor is added to allow solidification of the composition within 5 minutes at room temperature or 37°C.

52. The method of any one of claims 39-51 , wherein the composition has a pH between 6.5 and 7.8.

53. The method of claim 45, wherein the chitosan is 60% to 100% deacetylated with an average molecular weight ranging from 1 kDa to 10 MDa.

54. The method of claim 53, wherein the chitosan has an average molecular weight ranging from 10 kDa to 150 kDa.

55. The method of any one of claims 39-54, wherein the blood component is selected from the group consisting of whole blood, processed blood, venous blood, arterial blood, blood from bone, blood from bone-marrow, bone marrow, umbilical cord blood, plasma, platelet-enriched plasma and placenta blood.

56. The method of claim 55, wherein the blood component is selected from the group consisting of erythrocytes, leukocytes, monocytes, platelets, fibrinogen and thrombin.

57. The method of claim 55, wherein the blood component further comprises platelet rich plasma free of erythrocytes.

58. The method of any one of claims 39-57, wherein the composition is thermogelling.

59. The method of any one of claims 39-58, wherein the composition further comprises a Colony-stimulating factor (CSF).

60. The method of claim 59, wherein said CSF is selected from the group consisting of Granulocyte Colony stimulating factor (G-CSF), Granulocyte Macrophage Colony stimulating factor (GM-CSF), and Macrophage Colony stimulating factor (M-CSF).

61. The method of claim 59, wherein said CSF is Neupogen®.

62. The method of claim 42, wherein the mixing ratio of clotting factor/composition is between 1 :10 and 1 :100 v/v.

63. The method of claim 42, wherein the clotting factor is thrombin at a concentration of 0.001 U/ml to 1000 U/ml.

64. The method of claim 42, wherein the clotting factor is tissue factor at a concentration of 0.1 pg/ml to 10 pg/ml.

65. The method of claim 42, wherein the clotting factor is rVlla at a concentration between 50 pg/ml to 500 pg/ml.

66. The method of claim 42, wherein the clotting factor is factor XI I la at a concentration of 0.01 U/ml to 100 U/ml.