Mesenchymal stem cell-mediated suppression of hypertrophic scarring is p53 dependent in a rabbit ear model.

INTRODUCTION: Mesenchymal stem cells (MSCs) are considered to play important roles in wound repair and tissue remodeling. Hypertrophic scar (HTS) is a cutaneous condition characterized by deposits of excessive amount of collagen after an acute skin injury. However, currently there is little knowledge about the direct relationship between MSCs and HTS. METHODS: The hypertrophic scar model was established on rabbit ears. MSCs were isolated from rabbit femur bone marrow and transplanted through ear artery injection. Hypertrophic scar formation was examined using frozen-section analysis, hematoxylin and eosin (HE) staining, Masson's trichrome staining, and scar elevation index. The role of p53 in the MSCs-mediated anti-scarring effect was examined by gene knockdown using p53 shRNA. RESULTS: In this study, MSCs engraftment through ear artery injection significantly inhibited the hypertrophic scarring in a rabbit ear hypertrophic scar model, while this anti-scarring function could be abrogated by p53 gene knockdown in MSCs. Additionally, we found that MSCs down-regulated the expression of TGF-ß receptor I (TßRI) and alpha-smooth muscle actin (α-SMA) at both mRNA and protein levels in a paracrine manner, and this down-regulation was rescued by p53 gene knockdown. Moreover, our results showed that MSCs with p53 gene knockdown promoted the proliferation of fibroblasts through increasing nitric oxide (NO) production. CONCLUSIONS: These results suggest that MSCs inhibit the formation of HTS in a p53 dependent manner through at least two mechanisms: inhibition of the transformation of HTS fibroblast to myofibroblast; and inhibition of the proliferation of fibroblasts through inhibition of NO production.

[The thoracodorsal artery musculocutaneous perforator flap: anatomic study and clinical significance].

OBJECTIVE: To investigate the feasibility of clinical application of the thoracodorsal artery musculocutaneous perforator flap (TAMPF). METHODS: (1) The morphosis and blood supply of TAP flap on 15 formalized adult cadavers(30 sides) were examined by microsurgery anatomy. (2) An imitative operation of the TAMP flap and latissimus dorsi flap on 1 formalized adult cadavers (2 sides) was conducted. RESULTS: (1) A total of 102 musculocutaneous perforators larger than 0.5 mm were found in 16 specimens(32 sides). 56 perforators (55%) were originated from the medial branch and 46 (45%) originated from the lateral branch. The biggest perforator is (0.82 +/- 0.11) mm (0.68 - 1.08 mm). There was an average of 1.9 perforators (range, 1 - 3 perforators) of the medial branch and an average of 1.8 perforators (range, 1 - 3 perforators) of the lateral branch. Additionally, there were 24 perforators samller than 0.5 mm, and 76 perforators originated from intercostal artery and lumbar artery. (2) Musculocutaneous perforators over 0.5 mm were found only in proximity of the medial and lateral branches within a distance of 8.5 cm (6.4 cm - 9.2 cm) distal to the neurovascular hilus. CONCLUSIONS: With the characteristics of constant position, large caliber, long pedicle, the thoracodorsal artery musculocutaneous perforator was suitable to be musclocutaneous perforator flaps and "fan-shaped" flaps.

[Heel deep tissue defects were repaired by perineal tendofascial flap conjoined with adipofascial flap].

OBJECTIVE: To explore a new method and estimate its outcome to repair deep heel tissue injuries with local tissue flap. METHODS: At lower cnemis, a fat fascial flap combined with perineal tendofascial flap were designed and elevated between the lateral malleolars blank, the largest area is 6 cm x 13 cm, which were transplanted to cover naked calcaneal tendon and calcaneal bone, full-thickness free skin graft or middle-thickness free skin graft were grafted on flap. RESULTS: 6 patients suffered from heel tissue defects had been treated from January 2004 to November 2005. The smallest area was 3.5 cm x 4.0 cm and the largest was 4 cm x 6 cm. All fascial flaps and free skin grafts were successfully survived after operations. All patients were followed up 3-23 months, the operation areas were healed, the functions and configurations were satisfied. CONCLUSIONS: Perineal tendofascial flap conjoined with adipofasical flap and free skin graft are used to repair heel deep tissue defects, which is a handy, dependable way for repairing of the small tissue defects of the lower third of leg and heel.

[Preauricular lateral maxillocervical fasciocutaneous flap].

OBJECTIVE: To investigate the design and blood supply type of the reverse narrow pedicle lateral maxillocervical fasciocutaneous flap. METHODS: The reverse narrow pedicle lateral maxillocervical fasciocutaneous flap with its pedicle locate in front of auricle was designed to repair the defect caused by removing the malignant tumor in aged patients. The largest size is about 10 cm x 6 cm, the width of pedicle ranged from 2.5-3.0 cm, 2-4 cm in length. RESULTS: The flaps were used in 4 patients, age from 57 to 83 years old and the flap was designed as lateral maxillocervical fasciocutaneous flap. The flap was survived well in all patients, donor site can be closed without strain, no tumor relapsed. CONCLUSION: The flap should be included to be a reverse axial flap and it should be designed from jaw edge to chin. The pedicle couldn't be too narrow, in this way, donor site can be closed directly, and less surgical operation time needed. The patients can accept synthesize treatment early, for example actinotheraphy. It is an ideal choice for repair the defect caused by removing the malignant tumor in aged patients.