Surgical management for large chest keloids with internal mammary artery perforator flap

Keloids: A Review of Etiology, Prevention, and Treatment

Keloids are abnormal scars that cause significant emotional and physical distress in patients when inadequately treated. Keloid formation is theorized to occur as a result of an imbalance between an increased synthesis of collagen and extracellular matrix and decreased degradation of these products. Inflammatory mediators- namely, transforming growth factor beta-have been proposed to influence the dysregulation of collagen remodeling in the scar healing process. Though limited, current knowledge of keloid pathophysiology has guided clinicians to explore novel therapies for keloid prevention and treatment. In addition to conducting research refining the use of common therapies, such as steroids and radiation, clinicians have evaluated the potential of anti-inflammatory and chemotherapeutic molecules to suppress keloid recurrence. Procedural focused therapies, such as cryotherapy and lasers, have also found a role in reducing keloid symptomatology. The purpose of this report is to examine the current literature and review the mechanisms of action, efficacy, and side effects of different keloid therapies. Despite the growing literature investigating reliable methods for keloid management, there are no standardized guidelines or treatment protocols supported by academic governing bodies. Stronger evidence with high-fidelity randomized clinical trials will be needed to determine the optimal therapy regimens for keloids.

Clinical Application of the Internal Mammary Artery Perforator Adipofascial Flap

Background:

Skin ulcers on the anterior chest wall are caused mainly by radiation therapy for breast cancer and anterior mediastinitis after thoracotomy, and they are often refractory. Some muscle flaps are commonly used for anterior chest wall reconstruction, but muscle flaps accompany high invasion. We used the internal mammary artery perforator (IMAP) adipofascial flap and IMAP skin flap for the anterior chest wall reconstruction.

Methods:

We examined the IMAPs using a handheld Doppler device and contrast-enhanced computerized tomography preoperatively. Each flap was designed based on the location of the IMAP and the size of the flap was dependent on the coverage required by the size and location of the skin ulcer. The location of the IMAPs functioned as the pivot point of the flap and the flap was flipped or swung on the defect.

Results:

We used IMAP adipofascial flap for 2 cases and IMAP skin flap for 1 case. In those 3 cases, we could elevate the flap with no complications even after the internal mammary artery had been harvested. There was no recurrence of the skin ulcer or wound infection after the operation.

Conclusions:

In this study, we reported 3 cases of skin ulcer on the anterior chest wall reconstructed with the IMAP adipofascial and skin flap. To our knowledge, this is the first report of the use of the IMAP flap as an adipofascial flap. The IMAP adipofascial flap accompanies less invasion than muscle flaps and the surgical procedure is relatively easy. The IMAP adopofascial flap is considered as one of the effective means for anterior chest wall reconstruction.

Peroxisome proliferator-activated receptor-γ agonist troglitazone suppresses transforming growth factor-β1 signalling through miR-92b upregulation-inhibited Axl expression in human keloid fibroblasts in vitro

Keloid, a skin benign tumor, is characterized by overgrowth of fibroblasts and the excessive deposition of extracellular matrix in wounded skin. Peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist was recently evaluated to inhibit fibrosis. This study explored the underlying mechanisms. Fibroblasts isolated from 25 keloid patients (KFs) and fibroblasts isolated from healthy controls (NSFBs) were also subjected to treatment with PPAR-γ agonist troglitazone and antagonist GW9662 or for transfection with miR-92 mimics or inhibitor, Axl siRNA, and miR-92b or Axl promoter constructs, as well as being subjected to qRT-PCR, ELISA, Western blot, protein array, luciferase, and ChIP assays. The data demonstrated that TGF-β1 and Axl proteins were significantly elevated in samples from keloid patients, while troglitazone treatment significantly reduced levels of TGF-β1 and Axl mRNA and proteins in KFs. Moreover, knockdown of Axl expression reduced expression of TGF-β1 and its pathway genes (such as α-SMA and Snail). PPAR-γ regulation of Axl expression was through transcriptional activation of miR-92b. miR-92b expression downregulated Axl expression at both mRNA and protein levels, whereas GW9662 completely reversed the inhibitory effects of miR-92b mimics on Axl expression. Gene ontology analysis of miR-92b targeting genes showed that TGF-β and Axl were both potential targets of miR-92b, as confirmed by luciferase assay. These findings demonstrated that PPAR-γ-induced miR-92b expression inhibited Axl expression and in turn reduced expression of TGF-β1 and the downstream genes in KFs, suggesting that targeting of this novel gene pathway may be useful for therapeutic control of fibrosis or keloid.