Young Joon Jun

Designing a highly bioactive 3D bone-regenerative scaffold by surface immobilization of nano-hydroxyapatite

A novel approach to the fabrication of porous scaffolds with surface-immobilized nano-hydroxyapatite (N-HAp) is developed for effective bone tissue engineering. The discrete nano-level anchoring of N-HAp on the pore surface of chitosan scaffolds is achieved using surface-repellent stable colloidal N-HAp with surface phosphate functionality. Field-emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS) confirm pronounced exposure of N-HAp on the surfaces of chitosan scaffolds at the nano-level, which can not be accomplished with the conventional polymer/N-HAp composite scaffolds. This rational surface engineering enables surface-anchored N-HAp to express its overall intrinsic bioactivity, since N-HAp is not phase-mixed with the polymers. The porous chitosan scaffolds with surface-immobilized N-HAp provide more favorable environments than conventional bulk phase-mixed chitosan/N-HAp scaffolds in terms of cellular interaction and growth. In vitro biological evaluation using alkaline phosphatase activity assay supports that immobilized N-HAp on pore surfaces of chitosan scaffolds contributed to the more enhanced in vitro osteogenic potential. In addition, scaffolds with surface-exposed N-HAp provide favorable environments for enhanced in vivo bone tissue growth, estimated by characteristic biomarkers of bone formation such as collagen. The results suggest that the newly developed hybrid scaffolds with surface-immobilized N-HAp may serve as useful 3D substrates with pore surfaces featuring excellent bone tissue-regenerative properties.

In vivo cartilage formation using chondrogenic-differentiated human adipose-derived mesenchymal stem cells mixed with fibrin glue.

Human adipose-derived mesenchymal stem cells (MSCs) were differentiated into chondrogenic MSCs, and fibrin glue was used together to explore the feasibility of whether cartilages can be generated in vivo by injecting the differentiated cells. Mesenchymal stem cells extracted from human adipose were differentiated into chondrogenic MSCs, and such differentiated cells mixed with fibrin glue were injected subcutaneously into the back of the nude mouse. In addition to visual evaluation of the tissues formed after 4, 8, and 12 weeks, hematoxylin-eosin staining, Masson trichrome staining, measurement of glycosaminoglycan concentration using dimethylmethylene blue, agreecan through reverse transcriptase-polymerase chain reaction, type II collagen, and expression of SOX-9 were verified. Moreover, the results were compared with 2 groups of controls: 1 control group that received only injection of chondrogenic-differentiated MSC and the supporting control group that received only fibrin glue injection. For the experimental group, cartilage-like tissues were formed after 4, 8, and 12 weeks. Formation of cartilage tissues was not observed in any of 4, 8, and 12 weeks of the control group. The supporting control group had only a small structure formation after 4 weeks, but the formed structure was completely decomposed by the 8th and 12th weeks. The range of staining dramatically increased with time at 4, 8, and 12 weeks in Masson trichrome staining. The concentration of glycosaminoglycan also increased with time. The increased level was statistically significant with more than 3 times more after 8 weeks compared with 4 weeks and more than 2 times more after 12 weeks compared with 8 weeks. Also, in reverse transcriptase-polymerase chain reaction at 4, 8, and 12 weeks, all results expressed a cartilage-specific gene called aggrecan, type II collagen, and SOX-9. The study verified that the chondrogenic-differentiated MSCs derived from human adipose tissues with fibrin glue can proliferate and form new cartilage. Our findings suggest that formation of cartilages in vivo is possible.

The effect of platelet rich plasma combined with microfracture for the treatment of chondral defect in a rabbit knee

Recently, many clinical studies have been published regarding platelet-rich plasma (PRP) injection for early degenerative joint disease. We evaluated the cartilage repair potential of platelet-rich plasma when injected into the knee joint. Articular, cartilage defects 4 mm in diameter and circular in shape were made in the trochlear region of 20 knees in 10 New Zealand white rabbits who were divided into two groups. The left knees in the control group underwent microfracture, and the right knees in the experimental group underwent microfracture with subsequent injection of platelet-rich plasma. At week 12 following the surgery, the cartilage was observed macroscopically and histologically compared in the two groups. The control group showed incomplete and irregular fibrous tissue formation in the defect. The experimental group showed nearly complete defect coverage with neo-cartilage. In the histologic scoring, comparison of the control group and the experimental group differed significantly (p < 0.05).Therefore, injection of platelet-rich plasma used to treat articular cartilage defects of the knee appears to have some effect for cartilage regeneration.

The effect of diabetes on the wound healing potential of adipose-tissue derived stem cells

To investigate whether diabetes mellitus affects the wound‐healing‐promoting potential of adipose tissue‐derived stem cells, we designed a wound‐healing model using diabetic mice. We compared the degree of wound healing between wounds treated with normal adipose tissue‐derived stem cells and wounds treated with diabetic adipose tissue‐derived stem cells. We evaluated the wound‐healing rate, the epithelial tongue distance, the area of granulation tissue, the number of capillary and the number of Ki‐67‐stained cells. The wound‐healing rate was significantly higher in the normal adipose tissue‐derived stem cells group than in the diabetic adipose tissue‐derived stem cells group; it was also significantly higher in the normal adipose tissue‐derived stem cells group than in the control group. Although the diabetic adipose tissue‐derived stem cells group showed a better wound‐healing rate than the control group, the difference was not statistically significant. Similar trends were observed for the other parameters examined: re‐epithelisation and keratinocyte proliferation; granulation tissue formation; and dermal regeneration. However, with regard to the number of capillary, diabetic adipose tissue‐derived stem cells retained their ability to promote neovasculisation and angiogenesis. These results reflect the general impairment of the therapeutic potential of diabetic adipose tissue‐derived stem cells in vivo.

Anatomical Study of the Fingertip Artery in Tamai Zone I: Clinical Significance in Fingertip Replantation.

Background There are a few previous studies of the vascular anatomy of the fingertips. The aim of this study was to evaluate this anatomy and the distribution of fingertip arteries. Patients and Methods A total of 31 cadaveric hands were used for evaluation of the vascular pattern of the fingertips on X‐ray images obtained using a radiopaque material. We analyze the anatomy of the fingertip arteries, and classified it into three types in Tamai zone I. If only one dominant artery branched off from the distal transverse palmar arch, it was classified as type I. If the fingertip had branches of two dominant arteries, it was classified as type II, and if the fingertip had branches of three or more dominant arteries, it was classified as type III. Results The incidence of type I was 27%, that of type II was 28%, and the incidence of type III was 45%, the latter being the most frequent. In addition, we analyzed the pattern in each finger. The frequency of type III decreased from the index finger to the little finger, and the frequencies of types I and II increased from the index finger to the little finger. Conclusion Type III was the most common type in fingers, and its frequency decreased from the index finger to the little finger.

Prevention of Postsurgical Scars: Comparsion of Efficacy and Convenience between Silicone Gel Sheet and Topical Silicone Gel

To date, few studies have compared the effectiveness of topical silicone gels versus that of silicone gel sheets in preventing scars. In this prospective study, we compared the efficacy and the convenience of use of the 2 products. We enrolled 30 patients who had undergone a surgical procedure 2 weeks to 3 months before joining the study. These participants were randomly assigned to 2 treatment arms: one for treatment with a silicone gel sheet, and the other for treatment with a topical silicone gel. Vancouver Scar Scale (VSS) scores were obtained for all patients; in addition, participants completed scoring patient questionnaires 1 and 3 months after treatment onset. Our results reveal not only that no significant difference in efficacy exists between the 2 products but also that topical silicone gels are more convenient to use. While previous studies have advocated for silicone gel sheets as first-line therapies in postoperative scar management, we maintain that similar effects can be expected with topical silicone gel. The authors recommend that, when clinicians have a choice of silicone-based products for scar prevention, they should focus on each patients scar location, lifestyle, and willingness to undergo scar prevention treatment. Graphical Abstract

Effects of human adipose-derived stem cells on the regeneration of damaged visceral pleural mesothelial cells: a morphological study in a rabbit model

OBJECTIVES Although an alveolar air leak (AAL) after pulmonary resection is a troublesome complication that diminishes a patients quality of life and increases medical costs, current treatment and preventive methods for AAL are not effective. Therefore, we transplanted adipose-derived stem cells (ASCs) to the damaged visceral pleura to facilitate the regeneration of mesothelial cells and investigated the possibility of cell therapy as a treatment option for AAL. METHODS Stem cells were isolated and cultured from discarded fat tissues that were collected after liposuction procedures. Flow cytometry analysis was performed to evaluate their suitability as mesenchymal stem cells. Cultured stem cells were seeded onto polyglycolic acid (PGA) sheets and incubated for 5 days. Under general anaesthesia, 10 New Zealand rabbits underwent thoracotomies. After the visceral pleura was damaged, PGA sheets containing ASCs were transplanted into 5 rabbits (ASC group) and PGA sheets without cells were transplanted into the other 5 rabbits (control group). Rethoracotomies were performed after 4 weeks, and the transplanted areas in the visceral pleura were excised for analysis. Haematoxylin and eosin and Azan staining were performed. In addition, electron microscopic examinations were performed to investigate the ultrastructure of the regenerating mesothelium. RESULTS Cultured stem cells were positive for the surface proteins CD13, CD29, CD49d, CD90 and CD105, whereas they were negative for CD34, CD45 and human leukocyte antigen (HLA)-DR. The adhesions between the transplanted visceral pleura and parietal pleura were weaker in the ASC group than in the control group. On histological examination, the mesothelial cell monolayer of the visceral pleura was well preserved in the ASC group, whereas it was frequently lost in the control group. Electron microscopy demonstrated that the mesothelial cell monolayer and its abundant microvilli were well preserved in the ASC group, but were absent or disintegrated in the control group. CONCLUSIONS Transplantation of ASCs to the damaged visceral pleura can contribute to the treatment and prevention of AAL by improving the regeneration of mesothelial cells.

Open reduction in trapdoor-type blowout fractures using absorbable mesh plates.

PurposeIn many cases of trapdoor-type orbital blowout fracture, the bony segment has a stable hinge consisting of a greenstick fracture and the sinus mucoperiosteum that is attached to the intact orbital wall. If the displaced bony segment opposite the hinge will be reduced into its original position and will be fixed onto the unaffected bone, the orbital fracture may be reconstructed via the internal fixation of the bony segment itself rather than requiring substitution with an alloplastic implant or a bone graft. MethodsA retrospective study was conducted from January 2008 to February 2010 in 34 patients with blowout fracture, via retrospective chart review, including detailed preoperative and postoperative evaluations, age, sex, symptoms, and signs, and based on the postoperative complications. The subciliary, transconjunctival, and transcaruncular approaches were used to expose the orbital floor under general anesthesia. The herniated orbital soft tissue was carefully reduced. The displaced bony segment was carefully pulled up and placed in its original anatomic position with a skin hook. A small absorbable mesh plate was inserted between the normal orbital wall and the bony segment, tangential to the edge of the bony defect at the dependent portion. ResultsPostoperative examinations such as the traction and forced duction tests showed no eye movement limitation and surgical complications. During the follow-up period, no complications occurred, and the orbital wall was accurately reconstructed in its original anatomic position, as confirmed by postoperative computed tomography scans. ConclusionsThe advantages of internal fixation include anatomic reconstruction of the orbital wall, preservation of the original orbital bone and the mucoperiosteum of the sinus resulting in rapid wound healing and normal mucus drainage function of the sinus, simplicity of the procedure, and the absence of surgery-related complications. This technique is presented as one of the preferred treatments for trapdoor-type orbital blowout fracture.

Scrotal reconstruction using a superficial circumflex iliac artery perforator flap following Fournier's gangrene.

Fourniers gangrene is a type of necrotising fasciitis around the scrotum and perineum. Because of its aggressive nature, patients should be treated with broad‐spectrum antibiotics and emergency, radical debridement during the acute phase. After recovering from the acute phase, reconstruction of the scrotal and perineal soft tissue defects is needed and is often challenging. Traditionally, various reconstruction methods have been used, including skin grafts, fasciocutaneous flaps and musculocutaneous flaps, each with its pros and cons. We successfully covered a wide scrotal defect using a superficial circumflex iliac artery perforator flap, which has not been previously reported for this indication. The design and operative technique are introduced in this study.

Efficacy and Safety of Porcine Collagen Filler for Nasolabial Fold Correction in Asians: A Prospective Multicenter, 12 Months Follow-up Study

Recently, injectable dermal fillers have become important alternatives to surgical procedures for the correction of facial wrinkles. Bovine collagen is the first approved material for filler injection, and several studies have shown its efficacy. However, the risk of developing an allergic reaction and xenogenic transmission of bovine spongiform encephalopathy remain among its disadvantages. In this randomized, double-blinded, split-face study, we compared the efficacy and safety of a porcine collagen filler (TheraFill®) with that of a bovine collagen filler (KOKEN®) for nasolabial fold correction. A total of sixty one patients with mild to severe nasolabial fold were randomized to receive TheraFill® and KOKEN® on contralateral sides of the face. During the 12-month follow-up period, improvement in the Wrinkle-Severity Rating Scale score was slightly higher in TheraFill® group than KOKEN® group, although the difference was not statistically significant. No serious adverse reactions were observed and both materials were tolerable in most cases. In conclusion, the long-term effect of TheraFill® on nasolabial fold correction was comparable to that of KOKEN®, and it may be a good alternative to bovine collagen filler. Graphical Abstract