Sunyoung Kwon

Evaluation of an Amniotic Membrane-Collagen Dermal Substitute in the Management of Full-Thickness Skin Defects in a Pig

Background To minimize the inflammatory reaction and improve healing, a new modified dermal substitute composed of an atelocollagen, chondroitin-6-sulfate, and amniotic membrane (AM) was applied to full-thickness skin defects in a pig. Atelocollagen was extracted from bovine skin, and two modified dermal substitutes were generated according to the cross-linking type. Methods The AM-collagen dermal substitutes were characterized and compared with currently used dermal substitutes in a pig skin defect model. There were five experimental groups: dehydrothermal (DHT) cross-linking atelocollagen with the AM on the top (AM-DHT), DHT and chemical cross-linking atelocollagen with the AM on the top (AM-DHT/chemical), Terudermis, Integra, and AlloDerm. After 3×3 cm full-thickness skin defects on the back of a pig were created, each dermal substitutes dermal substitutes was randomly grafted on the defects. Two weeks after grafting, autologous partial-thickness skin was over-grafted on the neodermis. The take rate of the dermal substitutes, skin, and histological sections were all assessed at 1, 2, and 4 weeks postoperatively. Results More rapid healing and a higher take rate were evident in the AM-DHT and Terudermis groups. Histological examination revealed fewer inflammatory cells and more fibroblast hyperplasia in these two groups. Four weeks after surgery, the amount of newly formed collagen was significantly more appropriate in the AM-DHT group. Conclusions These observations provide supporting evidence that a newly developed amniotic-collagen dermal substitute may inhibit inflammatory reactions and promote wound healing.

Immunoglobulin G4-related sclerosing disease invading the trachea and superior vena cava in mediastinum

It is well known that immunoglobulin G4 (IgG4)-related sclerosing disease usually occurs in the pancreas, bile duct and gall bladder, but not in the mediastinum, trachea or superior vena cava (SVC). In this case, a patient underwent mediastinal mass excision and trachea resection and repair for a mediastinal and intratracheal mass 15 years ago. This mass was diagnosed postoperatively as an inflammatory pseudotumour (plasma cell granuloma). Subsequently, a mass was found to have recurred in the SVC. We performed a mass excision and innominate vein to the right atrium auricle bypass operation. The mass was diagnosed as IgG4-related sclerosing disease. This patient is now disease and recurrence free.

Experimental pig model of clinically relevant wound healing delay by intrinsic factors

The intrinsic factors associated with delayed wounds are ischaemia, infection, the presence of necrotic tissue and the presence of foreign bodies. This study was designed to create adaptable intrinsic factors induced delayed wound healing model in the pig, similar to clinical conditions. Four pigs were used in this study. Ten 4 × 4 cm fresh full‐thickness skin defect wounds were made on the back of each pig. Double‐flanged blocks made of silicon, a material that induces foreign body reactions, tissue ischaemia and causes local wound infection, were inserted into half of the wounds (n = 5) and removed at weeks 1, 2 or 3. The other wounds (n = 5) were left open for control purposes. Biopsies were obtained at weeks 1–4 for histological examinations and to evaluate inflammatory cytokines, which included tumour necrosis factor‐α (TNF‐α), interleukin (IL)‐1β and IL‐6. A Periscan PIM 3 Laser was used to measure degrees of ischaemia. A Visitrak Digital® device was used to measure the sizes of unhealed wounds. After 3 weeks, unhealed mean wound sizes were 30·72 ± 3·36 and 2·91 ± 1·51 cm2, in the experimental and control groups, respectively. Laser Doppler showed limited perfusion at wound margins in wounds containing silicone blocks. Histological findings corresponding to the severity of chronic inflammation were markedly higher and persisted until week 3 in the experimental group. The levels of IL‐1 and TNF‐α in the third week were statistically significantly higher in the model group. Also, in the fourth week, the level of TNF‐α in the model group was significantly higher. Epithelialisation was not complete at the end of the fourth week despite removing silicone blocks in the experimental group. On the basis of macroscopic and histological evaluations and molecular assessments, the described wound model has the characteristics of wound ischaemia and necrosis and persistent inflammation, which are very similar to delayed wounds of patients.

Polydeoxyribonucleotide (PDRN) Improves Peripheral Tissue Oxygenation and Accelerates Angiogenesis in Diabetic Foot Ulcers

Background Polydeoxyribonucleotide (PDRN) is known to have anti-inflammatory and angiogenic effects and to accelerate wound healing. The aim of this study was to investigate whether PDRN could improve peripheral tissue oxygenation and angiogenesis in diabetic foot ulcers. Methods This was a prospective randomized controlled clinical trial. Twenty patients with a non-healing diabetic foot ulcer were randomly distributed into a control group (n=10) and a PDRN group (n=10). Initial surgical debridement and secondary surgical procedures such as a split-thickness skin graft, primary closure, or local flap were performed. Between the initial surgical debridement and secondary surgical procedures, 0.9% normal saline (3 mL) or PDRN was injected for 2 weeks by the intramuscular (1 ampule, 3 mL, 5.625 mg, 5 days per week) and perilesional routes (1 ampule, 3 mL, 5.625 mg, 2 days per week). Transcutaneous oxygen tension (TcPO2) was evaluated using the Periflux System 5000 with TcPO2/CO2 unit 5040 before the injections and on days 1, 3, 7, 14, and 28 after the start of the injections. A pathologic review (hematoxylin and eosin stain) of the debrided specimens was conducted by a pathologist, and vessel density (average number of vessels per visual field) was calculated. Results Compared with the control group, the PDRN-treated group showed improvements in peripheral tissue oxygenation on day 7 (P<0.01), day 14 (P<0.001), and day 28 (P<0.001). The pathologic review of the specimens from the PDRN group showed increased angiogenesis and improved inflammation compared with the control group. No statistically significant difference was found between the control group and the PDRN group in terms of vessel density (P=0.094). Complete healing was achieved in every patient. Conclusions In this study, PDRN improved peripheral tissue oxygenation. Moreover, PDRN is thought to be effective in improving inflammation and angiogenesis in diabetic foot ulcers.