Abdominal skin tensile strength in aesthetic and massive weight loss patients and its role in ventral hernia repair

Injective hydrogel loaded with liposomes-encapsulated MY-1 promotes wound healing and increases tensile strength by accelerating fibroblast migration via the PI3K/AKT-Rac1 signaling pathway

Failed skin wound healing, through delayed wound healing or wound dehiscence, is a global public health issue that imposes significant burdens on individuals and society. Although the application of growth factor is an effective method to improve the pace and quality of wound healing, the clinically approved factors are limited. Parathyroid hormone (PTH) demonstrates promising results in wound healing by promoting collagen deposition and cell migration, but its application is limited by potentially inhibitory effects when administered continuously and locally. Through partially replacing and repeating the amino acid domains of PTH(1-34), we previously designed a novel PTH analog, PTH(3-34)(29-34) or MY-1, and found that it avoided the inhibitory effects of PTH while retaining its positive functions. To evaluate its role in wound healing, MY-1 was encapsulated in liposomes and incorporated into the methacryloyl gelatin (GelMA) hydrogel, through which an injectable nanocomposite hydrogel (GelMA-MY@Lipo, or GML) was developed. In vitro studies revealed that the GML had similar properties in terms of the appearance, microstructure, functional groups, swelling, and degradation capacities as the GelMA hydrogel. In vitro drug release testing showed a relatively more sustainable release of MY-1, which was still detectable in vivo 9 days post-application. When the GML was topically applied to the wound areas of rat models, wound closure as well as tensile strength were improved. Further studies showed that the effects of GML on wound repair and tensile strength were closely related to the promotion of fibroblast migration to the wound area through the controlled release of MY-1. Mechanically, MY-1 enhanced fibroblast migration by activating PI3K/AKT signaling and its downstream molecule, Rac1, by which it increased fibroblast aggregation in the early stage and resulting in denser collagen deposition at a later time. Overall, these findings demonstrated that the nanocomposite hydrogel system promoted skin wound healing and increased tensile strength, thus offering new potential in the treatment of wound healing.

Tracking stem cells in the incisional hernial sac: a gaze beyond pure tissue repairs

OBJECTIVE

the hernial sac is typically a bilayer structure consisting of connective tissue lined underneath by peritoneum. Some incidental findings on it, like smooth muscle cells and heterotopic ossification, can be explained as the end-stage metaplasia from undifferentiated cells. This study aimed to search for mesenchymal stem cells in the incisional hernial sac by an immuno-histochemistry screening test.

METHODS

fifteen specimens of them were submitted to histochemistry analysis using CD133 monoclonal antibodies, a specific marker of mesenchymal stem cells. The biopsies were obtained from patients submitted to pure tissue repair for incisional hernias - the transposition with the hernial sac technique (Lázaro da Silva, 1971).

RESULTS

two-thirds of the specimens expressed on average 20 (twenty) CD133+ cells in each one.

CONCLUSION

despite the screening nature of this study, the hernial sac may be considered a source of stem cells. This could explain those abnormal findings, and perhaps the induction of new fibroblasts in procedures that use it to optimize wound healing.