The significance of nanofiber polyglycolic acid for promoting tissue repair in a rat subcutaneous implantation model.

Among various biomaterials, we focused on nanofiber-based polyglycolic acid (PGA) fabric and examined the dynamics of cells that migrate within the non-woven fabric after implantation. The efficacy of nano-PGA as a tissue reinforcement in the process of subcutaneous tissue repair was immunohistochemically investigated. Two types of clinically available PGA non-woven sheet (nano-PGA: fiber diameter = 2.0 µm, conventional PGA: fiber diameter = 14.2 µm) were used and subcutaneously implanted in rats. Samples were collected 3 days, and 1, 2, 3, and 4 weeks after the implantation to perform histological and immunohistochemical (CD68, CD163, α-SMA, Type I collagen, CD34, MCP-1, IL-6, TNF-α, TGF-ß, VEGF, IgG) examinations to assess the expression of molecules related to inflammation or tissue repair. Immunohistochemical analysis in nano-PGA revealed that the intensity and positive cells (CD68, MCP-1, IL-6, TNF-α) significantly increased which indicated an early inflammatory response. This was followed by phagocytosis of nano-PGA with foreign body giant cells and CD68+ macrophages. Finally, the number of proliferating cells (CD163, α-SMA, TGF-ß) and angiogenesis (CD34, VEGF) for tissue repair promoted the formation of collagen fibers (type I collagen). Unlike nano-PGA, implantation of conventional PGA sheet resulted in a prolonged inflammatory response and was characterized by the presence of discontinuous collagen fibers with many foreign body giant cells, which did not lead to tissue repair. Nano-PGA sheets demonstrated a better tissue compatibility compared with conventional PGA by inducing early polarization to M2 phenotype macrophages, which triggered subsequent angiogenesis and tissue repair in the subcutaneous tissue.

Surface modification of the cubic micro-cartilage by collagenase treatment and its efficacy in cartilage regeneration for ear tissue engineering.

BACKGROUND: In order to enhance cartilage regeneration, surface modification of the cubic micro-cartilage with the collagenase treatment was tested and its efficacy to tissue engineer ear cartilage was investigated. MATERIALS AND METHODS: Harvested cubic micro-cartilages were treated with collagenase with different digestion time (0, 15, 60, and 120 min). Histological, ultrastructural (SEM and TEM), and Western blot analyses were carried out. Subsequently, A total of 45 dogs were used to tissue engineer ear cartilage. Using collagenase-treated micro-cartilage, the ear cartilage regeneration with the prepared dilution (8, 12.5, 25, 50, 100%) of micro-cartilage block seeding was performed to determine the minimum amount of cartilage tissue required for ear tissue-engineering (n = 6 at each point in each group). At 10 weeks after surgery, samples were resected and subjected to histochemical and immune-histological evaluation for cartilage regeneration. RESULTS: In vitro study on micro-cartilage morphology and western blot analysis showed that collagenase digestion was optimal at 60 min for cartilage regeneration. In vivo evaluation on the reduced proportions of micro-cartilage block seeding onto implant scaffolds under 60-min collagenase digestion determined the minimum amount of cartilage tissue necessary to initiate a one-step ear cartilage regeneration in a canine autologous model, which was 12.5-25% of the original ear size. CONCLUSION: Tissue-engineering ear cartilage from limited volume of donor cartilage can possibly be achieved by the collagenase treatment on micro-cartilage to expand cartilage regeneration capacity, application of cytokine sustained-release system, and seeding on a suitable ear scaffold material.

Ethanol treatment of nanoPGA/PCL composite scaffolds enhances human chondrocyte development in the cellular microenvironment of tissue-engineered auricle constructs.

A major obstacle for tissue engineering ear-shaped cartilage is poorly developed tissue comprising cell-scaffold constructs. To address this issue, bioresorbable scaffolds of poly-ε-caprolactone (PCL) and polyglycolic acid nanofibers (nanoPGA) were evaluated using an ethanol treatment step before auricular chondrocyte scaffold seeding, an approach considered to enhance scaffold hydrophilicity and cartilage regeneration. Auricular chondrocytes were isolated from canine ears and human surgical samples discarded during otoplasty, including microtia reconstruction. Canine chondrocytes were seeded onto PCL and nanoPGA sheets either with or without ethanol treatment to examine cellular adhesion in vitro. Human chondrocytes were seeded onto three-dimensional bioresorbable composite scaffolds (PCL with surface coverage of nanoPGA) either with or without ethanol treatment and then implanted into athymic mice for 10 and 20 weeks. On construct retrieval, scanning electron microscopy showed canine auricular chondrocytes seeded onto ethanol-treated scaffolds in vitro developed extended cell processes contacting scaffold surfaces, a result suggesting cell-scaffold adhesion and a favorable microenvironment compared to the same cells with limited processes over untreated scaffolds. Adhesion of canine chondrocytes was statistically significantly greater (p ≤ 0.05) for ethanol-treated compared to untreated scaffold sheets. After implantation for 10 weeks, constructs of human auricular chondrocytes seeded onto ethanol-treated scaffolds were covered with glossy cartilage while constructs consisting of the same cells seeded onto untreated scaffolds revealed sparse connective tissue and cartilage regeneration. Following 10 weeks of implantation, RT-qPCR analyses of chondrocytes grown on ethanol-treated scaffolds showed greater expression levels for several cartilage-related genes compared to cells developed on untreated scaffolds with statistically significantly increased SRY-box transcription factor 5 (SOX5) and decreased interleukin-1α (inflammation-related) expression levels (p ≤ 0.05). Ethanol treatment of scaffolds led to increased cartilage production for 20- compared to 10-week constructs. While hydrophilicity of scaffolds was not assessed directly in the present findings, a possible factor supporting the summary data is that hydrophilicity may be enhanced for ethanol-treated nanoPGA/PCL scaffolds, an effect leading to improvement of chondrocyte adhesion, the cellular microenvironment and cartilage regeneration in tissue-engineered auricle constructs.

Efficacy of sliced nerves of different thickness in a biodegradable nerve conduit to promote Schwann cell migration and axonal growth: An experimental study in the rat model.

BACKGROUND: Using the rat sciatic nerve model, sliced nerves of different thickness was combined to a biodegradable nerve conduit and the amount of nerve fragment necessary to promote nerve regeneration was investigated. MATERIALS AND METHODS: Harvested sciatic nerve (n = 6) was processed in sliced nerve of the different width; 2, 1, 0.5 mm, respectively. Western blot analysis was carried out to determine protein expression of Erk1/2. Subsequently, a total of 246 rats were used to create a 10 mm gap in the sciatic nerve. A polyglycolic acid-based nerve conduit was used to bridge the gap, with one sliced (width; 2, 1, 0.5 mm) or two (width; 1 mm × 2) incorporated within the conduit (n = 6 at each point in each group). At 2, 4, 8, and 20 weeks after surgery, samples were resected and subjected to immune-histological, transmission electron microscopic, and motor functional evaluation for nerve regeneration. RESULTS: Western blot analysis demonstrated Erk1/2 expressions were significantly increased in the groups of 2-mm and 1-mm width and attenuated in the 0.5-mm width group (p < .05). The immune-histological study showed the migration of Schwann cells and axon elongation were significantly extended in the groups of 2-mm, 1-mm, and 1 mm × 2 width at 4 weeks (p < .01), in which nerve conduction velocity was marked at 20 weeks (p < .01) after implantation. CONCLUSION: When nerve tissue was inserted in the biodegradable nerve conduit as a sliced nerve, the method of inserting two sheets with a slice width of 1 mm most strongly accelerated motor function.

Third Toe Pulp Reconstruction Using the Contralateral Second Toe Hemi-pulp Free Flap.

A hemi-pulp flap is widely known as a flap useful for aesthetic and functional reconstruction of the fingers, and rarely used for toe reconstruction. We performed third toe pulp reconstruction using a free hemi-pulp flap harvested from the contralateral second toe to repair the tissue defect following toe replantation. An 18-year-old woman was injured with complete left third toe amputation and open fracture of the proximal phalanx of the left second toe in a traffic accident. On the same day, third toe replantation was urgently performed. After surgery, the third toe was partially taken, and had a toe pulp tissue defect due to necrosis. It was reconstructed with a free hemi-pulp flap prepared from the contralateral second toe. The flap was completely taken. Three years after surgery, the reconstructed left third toe was aesthetically favorable. Perception of the flap region was restored up to S2 without pain and there was no complication such as numbness, callus, and ulceration. In the flap donor site (right second toe), the skin graft was unnoticeable without pigmentation. Toe pulp reconstruction requires a sensory flap as low-invasive as possible with excellent sensory restoration, texture, feel, and shear property. This method is considered as one of the low-invasive, aesthetic, and functional reconstruction methods.

A Comparative Study of Nail Fold Approach and Microscopic Nail Bed Approach in the Surgical Treatment of Subungual Exostosis.

ABSTRACT: Subungual exostosis is a benign tumor that occurs under the nail plate of the distal phalanx and causes nail deformity and pain. There are many reports of recurrence and postoperative nail deformity, and the surgical approach needs to be reassessed. Two typical surgical approaches are from the nail fold and the nail bed. Here, we compare 2 surgical approaches for subungual exostosis that were performed in our department. Twenty-three cases of subungual exostosis were treated between 2010 and 2019; 12 cases were treated by the nail fold approach and 11 by the microscopic nail bed approach. The nail fold approach resulted in not only scarring but also nail deformities, such as onychodystrophy. There were 2 (18.2%) cases of recurrence. In the microscopic nail bed approach, there was no case of recurrence. It was possible to preserve the thinned nail bed by dissecting under a microscope, and the thinned nail bed did not become necrotic in any cases. To solve postoperative nail deformity and a high recurrence rate, sufficient resection and meticulous surgical procedure on the nail bed and nail matrix are essential. The microscopic nail bed approach satisfied both of these criteria and was considered to be a useful method for subungual exostosis.

Effects of Fiber Diameter and Spacing Size of an Artificial Scaffold on the In Vivo Cellular Response and Tissue Remodeling.

By mimicking the extracellular matrix, nonwoven fabrics can function as scaffolds for tissue engineering application ideally, and they have been characterized regarding their fiber diameter and fiber spacing (spacing size) in vitro. We chronologically examined the in vivo effects of these fabrics on the cellular response and tissue remodeling. Four types of nonwoven polyglycolic acid fabrics (Fabric-0.7, Fabric-0.9, Fabric-3, and Fabric-16 with fiber diameters of 0.7, 0.9, 3.0, and 16.2 µm and spacing sizes of 2.0, 19.3, 19.0, and 825.4 µm, respectively) were implanted into the rat dorsum and subjected to histologic and immunohistochemical analyses from day 3 to 70. With Fabric-0.7, inflammatory cells (mainly M1 macrophages) and myofibroblasts with collagen type III accumulated mainly on the surface of the fabric and did not infiltrate inside the fabric initially, likely due to the narrow fiber space. Massive formation of collagen type I then appeared with the degradation of the fabrics, and finally, the remodeled tissue turned into a dense scar. With Fabric-0.9 and Fabric-3, inflammatory cells (predominantly M2 macrophages) were seen in all layers of the fabric initially. A mild increase in collagen type I was then seen, with few myofibroblasts, and the remodeled tissue ultimately showed a relatively little scar with an adequate thickness of the tissue induced by the fabrics. With Fabric-16, inflammatory cells (predominantly M1 macrophages) infiltrated into all layers of the fabric initially along with many myofibroblasts, especially in the hole. Lately, massive formation of collagen type I was noted due to the slow degradation of the fabric, with the shrinking of the fabric substantially, and the remodeled tissue finally turned to a dense scar. These findings suggest that optimizing the spacing size as well as the fiber diameter of artificial scaffolds may control the cellular response and tissue remodeling and facilitate favorable tissue regeneration without scar formation.

Use of sliced or minced peripheral nerve segments for nerve regeneration through a biodegradable nerve conduit: A preliminary study in the rat.

BACKGROUND: Using the rat sciatic nerve model, the difference in outcome using a nerve segment either sliced open or minced with a blade incorporated into a nerve conduit were compared and the relative effects upon the rate and completeness of the nerve regeneration was determined. MATERIALS AND METHODS: A 10-mm gap was created in the rat sciatic nerve and bridged with a biodegradable nerve conduit. Segments of the resected nerve (2-mm lengths) were prepared by either slicing the nerve with one longitudinal cut or by scalpel mincing of the nerve tissue, with insertion of the prepared nerve segment into the center of the conduit. Flow cytometry and Western blotting of these preparations were performed to measure viable cells and to examine the expression of Erk1/2 for neural regeneration potential with both treatments. in vivo nerve regeneration was evaluated at 2, 4, 8, and 20 weeks, using immunohistochemistry, transmission electron microscopy, muscle wet weight, and nerve conduction velocity determination. RESULTS: The sliced nerve group showed significantly greater Schwann cell migration with the subsequent axonal elongation at 4 weeks after implantation, in comparison to the minced nerve group and controls (unaltered conduit grafts). By 20 weeks anterior tibial muscle weight and nerve conduction velocity were also greater in the sliced nerve group in comparison to the other groups (p < .05). CONCLUSION: These findings suggest that insertion of a sliced section of nerve into a biodegradable nerve conduit can shorten the time for and improve the quality of nerve regeneration.

The Laterally Extended Paramedian Forehead Flap for Nasal Reconstruction: The Delay Technique Revisited.

BACKGROUND: Problems with poor circulation often occur when a large defect or a distant region, such as the apex of the nose, is covered with a paramedian forehead flap. Delay technique increases the safety of reconstruction procedures, but it has been used less frequently because a 2-stage surgery is necessary, and various other flaps and techniques have been developed. METHOD: We performed the delay technique of paramedian forehead flap at the same time as tumor resection. For the flap, a narrow pedicle of about 1-cm was prepared on the supratrochlear artery and vein, and the incision was extended toward the lateral side conforming to the defect morphology, and a paramedian forehead flap with a design consistent with the esthetic unit containing the defect was prepared. The region below the flap was dissected to create the flap bipedicle, and surgery was completed. RESULT: This procedure was used in 4 patients with malignant tumor of the external nose, and the flap survived perfectly in all patients. The postoperative esthetic outcome was also found to be good. CONCLUSIONS: This procedure does not increase the frequency of surgery, circulation in the flap is maintained, the flap pedicle on the supratrochlear artery can be made narrow, and flap thinning can be performed from the beginning. Coverage of an extensive defect is possible because a large flap can be excised, and satisfactory esthetic appearance can be obtained by matching with the esthetic unit. The delay technique for various flaps (not limited to forehead flap alone) should be considered an effective technique for the current treatment of malignant tumors.

Eye Comfort and Physiological Reconstruction of an Entire Upper Eyelid Defect.

OBJECTIVE: Reconstruction of an extensive full-thickness upper eyelid defect is challenging. The purpose of this report is to introduce this procedure with emphasis on reconstruction of the eyelid margin to obtain eye comfort. METHODS: We designed a technique using a radial forearm flap for the outer layer to reconstruct the entire eyelid after resection of Merkel cell carcinoma. In additional, the inner layer and the eyelid margin were reconstructed with a buccal mucosal graft and a reverse Hughes flap. RESULTS: There has been no recurrence of the tumor, opening and closing functions of the eyelid are maintained, and the patient has not complained of eye discomfort. CONCLUSION: Maintenance of mobility, flexibility, and a good ocular surface in contact with the sensitive cornea are the main foci of upper eyelid reconstruction, with an optimal fissure height and an appropriate contour of the eyelid. In addition, to obtain eye comfort, it is important to protect the cornea without significantly restricting eyelid mobility.

An analytical study of neocartilage from microtia and otoplasty surgical remnants: A possible application for BMP7 in microtia development and regeneration.

To investigate auricular reconstruction by tissue engineering means, this study compared cartilage regenerated from human chondrocytes obtained from either microtia or normal (conchal) tissues discarded from otoplasties. Isolated cells were expanded in vitro, seeded onto nanopolyglycolic acid (nanoPGA) sheets with or without addition of bone morphogenetic protein-7 (BMP7), and implanted in nude mice for 10 weeks. On specimen harvest, cartilage development was assessed by gross morphology, histology, and RT-qPCR and microarray analyses. Neocartilages from normal and microtia surgical tissues were found equivalent in their dimensions, qualitative degree of proteoglycan and elastic fiber staining, and quantitative gene expression levels of types II and III collagen, elastin, and SOX5. Microarray analysis, applied for the first time for normal and microtia neocartilage comparison, yielded no genes that were statistically significantly different in expression between these two sample groups. These results support use of microtia tissue as a cell source for normal auricular reconstruction. Comparison of normal and microtia cells, each seeded on nanoPGA and supplemented with BMP7 in a slow-release hydrogel, showed statistically significant differences in certain genes identified by microarray analysis. Such differences were also noted in several analyses comparing counterpart seeded cells without BMP7. Summary data suggest a possible application for BMP7 in microtia cartilage regeneration and encourage further studies to elucidate whether such genotypic differences translate to phenotypic characteristics of the human microtic ear. The present work advances understanding relevant to the potential clinical use of microtia surgical remnants as a suitable cell source for tissue engineering of the pinna.

Influence of Periosteum Location on the Bone and Cartilage in Tissue-Engineered Phalanx.

PURPOSE: This study investigated the influence of periosteal tissue of different origins on the calcification at the diaphysis and chondrocyte maturation at the epiphysis in an engineered phalanx. We hypothesized that the periosteum from long bones would better provide donor cells for bone formation and signals for maturation of the joint cartilage. METHODS: Periosteum was harvested from 4 locations (cranium, mandible, radius, and ilium) of calf bones. A human phalangeal bone-shaped, biodegradable, 3-dimensional scaffold hydroxyapatite-poly L-lactic-ɛ-caprolactone (HA-P[LA/CL]) was prepared using a human phalangeal bone-shaped template. A bioengineered human phalanx was fabricated by combining periosteal grafts with biodegradable copolymers. The joint cartilage region (chondrocyte/polyglycolic acid [PGA] composite) was subsequently sutured to the phalangeal bone region (periosteum/HA-P[LA/CL] composite) with absorbable sutures to make a human phalangeal bone model. These were then implanted in nude mice for maturation of the constructs. Macroscopic, radiographic, histological, and immune-histochemical evaluations were carried out to determine the relative influence of the periosteal graft source on bone and cartilage formation at 10 and 20 weeks after implantation. RESULTS: Calcification localized under the periosteum was noted in the cranium, radius, and ilium groups after 10 weeks, which markedly expanded at the modelled diaphysis after 20 weeks. The width in the minor axis direction tended to increase with time after grafting in the cranium group, whereas the longitudinal length increased in the radius and ilium groups. The joint cartilage thickness changed with time depending on the type of periosteum, and periosteum collected from the radius and ilium was associated with the greatest cartilage thickness in the joint cartilage maturation process. CONCLUSIONS: These results suggest that periosteum collected from radius of calves demonstrated superior bone formation and chondrocyte maturation in the engineered phalanx compared with other sources of periosteum. CLINICAL RELEVANCE: The osteogenic capacity depends on the periosteal source regardless of intramembranous or endochondral ossification. The appropriate periosteal choice is essential in the phalangeal bone and cartilage tissue engineering. The results are important for broadening tissue engineering possibilities for clinical application.

A clinical multi-center registry study on digital nerve repair using a biodegradable nerve conduit of PGA with external and internal collagen scaffolding.

BACKGROUND: In this study, we evaluated the clinical efficacy of a biodegradable nerve conduit constructed of polyglycolic acid (PGA) tube with external and internal collagen scaffolding for digital nerve repair. PATIENTS AND METHODS: A multi-center registry study was conducted in 11 locations between July 2013 and May 2016. Multiple mechanisms of injury included clean-cut (12 patients), crush (5 patients), and avulsion (3 patients) types of injuries. These patients underwent nerve repair with a biodegradable nerve conduit, with 9 patients having a primary repair and 11 patients having delayed repair. Average nerve gap was 16.7 mm (range: 1-50 mm). An average of 13 months follow-up (range: 12-15 months) was available including sensory assessments. RESULTS: Improved s2PD was found with less severe injury as in clean-cut (7.5 ± 1.5 mm), which was statistically significant in comparison to those in crush (9.8 ± 1.9 mm, P = .0384) and in avulsion (10.7 ± 4.7 mm, P = .0013) type injuries. A meaningful recovery (S3+ or S4) was observed in 90% of the 20 digital nerve repairs with a biodegradable nerve conduit of PGA with external and internal collagen scaffolding. Avulsion injuries had significantly lower levels of meaningful recovery (67%) in comparison to those of clean-cut (P = .0291) and crush (P = .0486) types of injury. No adverse effects were reported postoperatively. CONCLUSION: These results indicate that a biodegradable nerve conduit of PGA with external and internal collagen scaffolding is suitable for digital nerve repair of short nerve gaps with high levels of sensory recovery as measured by two-point discrimination.

A basic fibroblast growth factor slow-release system combined to a biodegradable nerve conduit improves endothelial cell and Schwann cell proliferation: A preliminary study in a rat model.

BACKGROUND: A basic fibroblast growth factor (bFGF) slow-release system was combined to a biodegradable nerve conduit with the hypothesis this slow-release system would increase the capacity to promote nerve vascularization and Schwann cell proliferation in a rat model. MATERIALS AND METHODS: Slow-release of bFGF was determined using Enzyme-Linked ImmunoSorbent Assay (ELISA). A total of 60 rats were used to create a 10 mm gap in the sciatic nerve. A polyglycolic acid-based nerve conduit was used to bridge the gap, either without or with a bFGF slow-release incorporated around the conduit (n = 30 in each group). At 2 (n = 6), 4 (n = 6), 8 (n = 6), and 20 (n = 12) weeks after surgery, samples were resected and subjected to histological, immunohistochemical, and transmission electron microscopic evaluation for nerve regeneration. RESULTS: Continuous release of bFGF was found during the observation period of 2 weeks. After in vivo implantation of the nerve conduit, greater endothelial cell migration and vascularization resulted at 2 weeks (proximal: 20.0 ± 2.0 vs. 12.7 ± 2.1, P = .01, middle: 17.3 ± 3.5 vs. 8.7 ± 3.2, P = .03). Schwann cells showed a trend toward greater proliferation and axonal growth had significant elongation (4.9 ± 1.1 mm vs. 2.8 ± 1.5 mm, P = .04) at 4 weeks after implantation. The number of myelinated nerve fibers, indicating nerve maturation, were increased 20 weeks after implantation (proximal: 83.3 ± 7.5 vs. 53.3 ± 5.5, P = .06, distal: 71.0 ± 12.5 vs. 44.0 ± 11.1, P = .04). CONCLUSIONS: These findings suggest that the bFGF slow-release system improves nerve vascularization and Schwann cell proliferation through the biodegradable nerve conduit.

Preliminary Study of PGA Fabric for Seromas at Latissimus Dorsi Flap Donor Sites.

BACKGROUND: Seroma formation is a major complication following latissimus dorsi (LD) flap transfer for breast reconstruction. We implanted a nonwoven polyglycolic acid (PGA) fabric-a biodegradable polymer-in the LD flap donor site and examined its effect on postoperative seroma formation and resolution in a comparative study on 38 patients undergoing primary 1-stage breast reconstruction by LD flap. METHOD: A PGA treatment group had a PGA fabric placed in the donor wound (PGA group, n = 20), whereas a second group was treated with standard donor site closure (control group, n = 18). The incidence of seromas was comparable between the groups. RESULT: There was a significant reduction in aspiration volume by needle aspiration after drain removal (P < 0.05) and in the time until seroma resolution (P < 0.01) in the PGA group compared with the control group. CONCLUSION: These results indicate that application of PGA at the LD donor site is useful in controlling postoperative seromas.

A Novel Method to Induce Cartilage Regeneration with Cubic Microcartilage.

Cartilage tissue is characterized by its poor regenerative properties, and the clinical performance of cartilage grafts to replace cartilage defects has been unsatisfactory. Recently, cartilage regeneration with mature chondrocytes and stem cells has been developed and applied in clinical settings. However, there are challenges with the use of mature chondrocytes and stem cells for tissue regeneration, including the high costs associated with the standard stem cell isolation methods and the decreased cell viability due to cell manipulation. Previous studies demonstrated that cartilage can be regenerated from chondrocyte clusters that contain stem cells. Based upon some of the existing techniques, the goal of this study was to develop a novel and practical method to induce cartilage regeneration. A microslicer device was developed to process cartilage tissues into micron-size cartilage (microcartilage) in a minimally invasive manner. We evaluated microcartilage sizes and demonstrated 100-400 µm as optimal for generating a high cell yield with collagenase digestion. In addition, autologous intrafascial implantation of the composites of microcartilage and an absorbable scaffold with a slow-release system of basic fibroblast growth factor (bFGF) was carried out to induce cartilage regeneration. Our results demonstrated that the extent of bFGF diffusion depends on the size of microcartilage, and that cartilage regeneration was induced most effectively with 100 µm of microcartilage via SOX5 upregulation. These findings suggest that cartilage regeneration is possible with microcartilage as a source of cells without ex vivo cell expansion.

Reconstruction of Severely Crushed Fingertip Amputations with Basic Fibroblast Growth Factor Slow Release System.

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