Exosomes Derived from Hypertrophic Scar Fibroblasts Suppress Melanogenesis in Normal Human Epidermal Melanocytes.

Post-burn hypertrophic scars often exhibit abnormal pigmentation. Exosomes play important roles in maintaining normal physiological homeostasis and in the pathological development of diseases. This study investigated the effects of the exosomes derived from hypertrophic scar fibroblasts (HTSFs) on melanocytes, which are pigment-producing cells. Normal fibroblasts (NFs) and HTSFs were isolated and cultured from normal skin and hypertrophic scar (HTS) tissue. Both the NF- and HTSF-exosomes were isolated from a cell culture medium and purified using a column-based technique. The normal human epidermal melanocytes were treated with both exosomes at a concentration of 100 µg/mL at different times. The cell proliferation, melanin content in the medium, apoptotic factors, transcription factors, melanin synthesis enzymes, signaling, signal transduction pathways, and activators of transcription factors (STAT) 1, 3, 5, and 6 were investigated. Compared with the Dulbecco's phosphate-buffered saline (DPBS)-treated controls and NF-exosomes, the HTSF-exosomes decreased the melanocyte proliferation and melanin secretion. The molecular patterns of apoptosis, proliferation, melanin synthesis, Smad and non-Smad signaling, and STATs were altered by the treatment with the HTSF-exosomes. No significant differences were observed between the DPBS-treated control and NF-exosome-treated cells. HTSF-derived exosomes may play a role in the pathological epidermal hypopigmentation observed in patients with HTS.

Effect of extracorporeal shock wave therapy for burn scar regeneration: A prospective, randomized, double-blinded study.

PURPOSE: This study aimed to investigate the regeneration effect of extracorporeal shock wave therapy (ESWT) on hypertrophic scar regeneration using objective measurements. METHODS: This was a double-blinded, randomized, controlled trial of 48 participants who had undergone autologous split-thickness skin grafting (STSG) with same artificial dermis. The ESWT group (n=25) received shock waves with low-energy flux density (0.05-0.30mJ/mm2). The interval between treatments is a 1-week. The ESWT group also received recommended treatment. The control group (n=23) only received standard treatment. We measured skin characteristics before treatment and after 6 weeks for both groups. RESULTS: No significant intergroup difference was noted at the initial evaluations (p>0.05). The pre- to post-treatment change in the scar thickness (p=0.03) and erythema (p=0.03), greater reduction was found in the ESWT group than control group. The pre- to post-treatment change in the sebum level (p=0.02), more increase was found in the ESWT group. We found no significant differences in the change measurements between the two groups for melanin levels (p=0.62) and transepidermal water loss (TEWL) (p=0.94). The changes (skin distensibility, biological skin elasticity, gross skin elasticity, and skin viscoelasticity) measured with the Cutometer showed no significant differences between the two groups (p=0.87, p=0.32, p=0.37, and p=0.29, respectively). CONCLUSION: This is the first report of ESWT on hypertrophic scar after burn using objective tools (melanin, erythema, sebum, TEWL, elasticity and thickness). ESWT has objective beneficial effects on burn-associated scar characteristics.

Contracture of skin graft in human burns: effect of artificial dermis.

BACKGROUND: Skin grafts with an artificial dermis have been widely used as a part of the efforts to minimize contractures and reduce donor-site scars. We conducted a prospective randomized clinical trial to study the effect of a dermal substitute by measuring the size of the graft after surgery for months. METHOD: The artificial dermis (Matriderm, Dr. Suwelack Skin and Health Care AG, Billerbeck, Germany) was applied in combination with a split-thickness autograft in 40 patients with acute burn wounds or scar reconstruction. Demographic and medical data were collected on each patient. We directly measured the graft size by using a transparent two-ply film (Visitrak Grid, Smith & Nephew Wound Management, Inc, Largo, FL, USA) intraoperatively and 1, 2, 3, and 6 months postoperatively. For effective data comparison, the size of the graft at the time of surgery was taken to be "100%." Then, the size in each phase was estimated in percentage (%). RESULT: During the 1st month, the average size was 89%. The figure decreased to 86% and 82% in the 2nd and 3rd months, respectively. In the 6th month, it slightly rebounded to 85% but failed to return to the original state. The size of patients with acute burns was smaller than the size of scar patients as follows: 85-91% in the 2nd month, 81-87% in the 3rd month, and 85-96% in the 6th month. CONCLUSION: This study examined the progress of skin grafts through the measurement of graft size in the human body. The grafted skin underwent contracture and remodeling for 3-6 months. In terms of skin contraction, an acute burn was more serious than scar reconstruction. The use of an artificial dermis that contains elastin is very effective from the functional and esthetic perspective by minimizing contractures and enhancing skin elasticity.

Proposed treatment protocol for frostbite: a retrospective analysis of 17 cases based on a 3-year single-institution experience.

BACKGROUND: This paper discusses the treatment protocol for patients with frostbite. METHODS: We performed a retrospective analysis of a series of 17 patients with second- and higher-degree frostbite who had been treated at our medical institution between 2010 and 2012. RESULTS: Our clinical series of patients (n=17) included 13 men and four women, whose mean age was 42.4±11.6 years (range, 22-67 years). The sites of injury include the foot in six patients (35.3%), the hand in six patients (35.3%) and the facial region in five patients (29.4%). Seven patients with second-degree frostbite were completely cured with only conservative treatment during a mean period of 12.7±3.3 days (range, 8-16 days). Of the five patients with third-degree frostbite, two underwent skin grafting following debridement, and the remaining three achieved a complete cure with conservative treatment during a mean period of 35±4.3 days (range, 29-39 days). Five patients with fourth-degree frostbite were treated with surgical procedures including amputation. CONCLUSIONS: With the appropriate conservative management in the early stage of onset, surgeons should decide on surgery after waiting for a sufficient period of time until the demarcation of the wound. Continuous management of patients is also needed to achieve functional recovery after a complete cure has been achieved. This should also be accompanied by patient education for the avoidance of re-exposure to cold environments.

Correction of postburn equinus deformity.

BACKGROUND: Equinus deformity is characterized by an abnormal tiptoe gait and does not allow normal walking, hence needing correction. Congenital causes of equinus deformity include neurological diseases such as cerebral palsy and poliomyelitis. Acquired causes include injuries such as extensive trauma. We have corrected equinus deformity from extensive lower leg burns by a single operation through excisional release of the scar, Achilles lengthening, and radial forearm free flap. METHODS: Fifteen patients with postburn equinus deformity who were treated between January 2000 and March 2012 were retrospectively studied. We investigated their age, sex, cause and severity of burn injury, equinus degree, ankle range of motion and the changes in the activity, extent of Achilles lengthening, flap size, complication, and the recurrence in these patients. RESULTS: The average degree of equinus deformity before the operation was 45 degrees. With an average Achilles lengthening of 4.6 cm, all patients achieved neutral position. The patients who had poor activity due to tiptoe gait before the operation showed good to fair levels of walking ability postoperatively. During an average follow-up period of 3 years and 9 months, no patients had a recurrence. CONCLUSIONS: Equinus deformity causes significant restrictions to walking and the reconstruction is a challenging problem. Although prevention is more important during the initial stages of treatment, we have successfully corrected patients with existing equinus deformity by scar release, Z-tenoplasty of Achilles, and radial forearm free flap.

Elbow reconstruction using island flap for burn patients.

BACKGROUND: Deep burns of the elbow lead to soft tissue necrosis and infection, with exposure of deep structures. Adequate wound coverage of this area requires thin, pliable, and durable tissue, while optimal functional recovery requires early coverage and functional rehabilitation. We have found 3 types of island flaps that provide reliable coverage for the elbow. METHODS: A retrospective study was performed on all patients who underwent flap coverage of an elbow defect at our hospital. The patients' data including age, sex, cause of injury, wound dimensions, timing of flap coverage, postoperative elbow motion, and complications were investigated. RESULTS: Between 2001 and 2012, 16 patients were treated at our hospital. The mean age was 53.3 years. Three kinds of flaps were performed: 9 latissimus dorsi flaps, 4 lateral arm flaps, and 4 radial forearm flaps. The average defect size was 183.5 cm(2) (range, 28 to 670 cm(2)). Wound coverage was performed at mean duration of 45.9 days (range, 14 to 91 days). The mean postoperative active elbow flexion was 98° (range, 85° to 115°). Partial flap failure occurred in 1 latissimus dorsi flap. Minor complications included partial flap loss (11.8%), hematoma (23.5%), seroma (35.3%), and wound infection (5.9%). CONCLUSIONS: Flap selection for elbow reconstruction is determined by the defect size and the extent of the adjacent tissue injury. Elbow reconstruction using an island flap is a single-staged, reliable, and relatively simple procedure that permits initiation of early rehabilitation, thereby improving a patient's functional outcome.

One stage reconstruction of skull exposed by burn injury using a tissue expansion technique.

BACKGROUND: An area of the skull exposed by burn injury has been covered by various methods including local flap, skin graft, or free flap surgery. Each method has disadvantages, such as postoperative alopecia or donor site morbidities. Due to the risk of osteomyelitis in the injured skull during the expansion period, tissue expansion was excluded from primary reconstruction. However, successful primary reconstruction was possible in burned skull by tissue expansion. METHODS: From January 2000 to 2011, tissue expansion surgery was performed on 10 patients who had sustained electrical burn injuries. In the 3 initial cases, removal of the injured part of the skull and a bone graft was performed. In the latter 7 cases, the injured skull tissue was preserved and covered with a scalp flap directly to obtain natural bone healing and bone remodeling. RESULTS: The mean age of patients was 49.9±12.2 years, with 8 male and 2 female. The size of the burn wound was an average of 119.6±36.7 cm(2). The mean expansion duration was 65.5±5.6 days, and the inflation volume was an average of 615±197.6 mL. Mean defect size was 122.2±34.9 cm(2). The complications including infection, hematoma, and the exposure of the expander were observed in 4 cases. Nonetheless, only 1 case required revision. CONCLUSIONS: Successful coverage was performed by tissue expansion surgery in burned skull primarily and no secondary reconstruction was needed. Although the risks of osteomyelitis during the expansion period were present, constant coverage of the injured skull and active wound treatment helped successful primary reconstruction of burned skull by tissue expansion.