A comparison of skin expansion and contraction between one expander and two expanders: a preliminary study

Hypoxia-induced CCL2/CCR2 axis in adipose-derived stem cells (ADSCs) promotes angiogenesis by human dermal microvascular endothelial cells (HDMECs) in flap tissues

Flap expansion has become an important method widely used in wound repair and organ reconstruction. However, distal skin flap ischemic necrosis remains a problematic complication. In this study, integrative bioinformatics analyses indicated the upregulation of C-C motif chemokine ligand 2 (CCL2) and C-C motif chemokine receptor 2 (CCR2) in reperfusion-exposed skin flap tissues. In adipose-derived stem cells (ADSCs, CD90-positive, CD29-positive, CD34-negative, and CD106-negative) exposed to hypoxia, HIF-1α and CCL2 levels were significantly elevated. Conditioned medium (CM) from hypoxia-stimulated ADSCs promoted HDMEC proliferation, migration, and tube formation, partially inhibited by sh-CCL2-induced CCL2 knockdown or neutralized antibody-induced CCL2 depletion in ADSCs. Consistently, CCL2, CCR2, TNF-α, TLR2, and TLR4 protein levels in HDMECs were significantly increased by hypoxia-treated ADSCs CM, and partially decreased by sh-CCL2-induced CCL2 knockdown or neutralizing antibody-induced CCL2 knockdown in ADSCs. In the flap expansion model, ADSCs transplantation significantly improved flap survival and angiogenesis by endothelial cells in flap tissues, whereas CCL2 knockdown in ADSCs partially eliminated the improvement by ADSCs transplantation; overexpression of CCL2 in ADSCs further promoted the effects of ADSCs transplantation on skin flap. In conclusion, the CCL2/CCR2 axis in ADSCs could be induced by hypoxia, promoting HDMEC proliferation, migration, and tube formation and improving flap survival and angiogenesis in flap tissues.

Pre-expanded bipedicled visor flap: an ideal option for the reconstruction of upper and lower lip defects postburn in Asian males

Background

Reconstruction of upper and lower lip subunits is a complicated and elusive challenge. For patients affected by defects involving upper and lower lip subunits, a technique able to reconstruct both aesthetic units with matched colour, sufficient contours and similar texture would be ideal. In this study, we present our experience with upper and lower lip reconstruction using the pre-expanded bipedicled visor flap.

Methods

From January 2014 to January 2017, 12 male patients presenting with defects of the upper and lower lip subunits were treated using this surgical technique. After a period of expansion of the scalp flap of over 6 months, the bipedicled visor flap was raised from both the parietal regions and rotated to resurface the defect. Delay and section of the pedicle were then performed.

Results

Twelve male patients with postburn scars aged 22 to 48 years (mean: 34 years) were successfully treated with no major complications. The donor site was closed primarily in all cases. Subsequent flap debulking and minor revisions were performed under local anaesthesia between 6 and 12 months postoperatively.

Conclusions

The pre-expanded bipedicled visor flap provides an effective and reliable option for upper and lower lip reconstruction with excellent colour and texture. It is feasible to achieve these results simultaneously from a single donor site by using a pre-expanded bipedicled visor flap.