No abstract

Epithelial sheet spreading is a fundamental cellular process that must be coordinated with cell division and differentiation to restore tissue integrity. Here we use consecutive serum deprivation and re-stimulation to reconstruct biphasic collective migration and proliferation in cultured sheets of human keratinocytes. In this system, a burst of long-range coordinated locomotion is rapidly generated throughout the cell sheet in the absence of wound edges. Migrating cohorts reach correlation lengths of several millimeters and display dependencies on epidermal growth factor receptor-mediated signaling, self-propelled polarized migration, and a G1/G0 cell cycle environment. The migration phase is temporally and spatially aligned with polarized cell divisions characterized by pre-mitotic nuclear migration to the cell front and asymmetric partitioning of nuclear promyelocytic leukemia bodies and lysosomes to opposite daughter cells. This study investigates underlying mechanisms contributing to the stark contrast between cells in a static quiescent state compared to the long-range coordinated collective migration seen in contact with blood serum.

The deep inferior epigastric artery perforator (DIEAP) flap is the gold standard of free flaps in breast reconstruction. However, until now little attention has been paid to reinnervation of the flap. The aim of this study was to examine the spontaneous reinnervation of the DIEAP flap after breast reconstruction. The study was cross-sectional, and included 29 women who had all previously had secondary reconstruction with a DIEAP flap after mastectomy for breast cancer. Pressure thresholds were analysed on the skin island of the flap using Semmes-Weinstein monofilaments. The measurements showed measurable sensation in 29 of the 30 flaps. Nine patients had normal or diminished light touch in one or more areas. We also found significant better pressure sensitivity when the medial was compared to the lateral side and the inferior to the superior side of the flap. Our data showed that DIEAP flaps reinnervate after breast reconstruction although there is no sensory nerve repair. We suggest that nerve ingrowth takes place from the sides and this seems to be more pronounced in the inferomedial part of the flap.

Damage to limbal stem cells as a result of injury or disease can lead to limbal stem cell deficiency (LSCD). This disease is characterized by decreased vision that is often painful and may progress to blindness. Clinical features include inflammation, neovascularization, and persistent cornea epithelial defects. Successful strategies for treatment involve transplantation of grafts harvested from the limbus of the alternate healthy eye, called conjunctival‐limbal autograft (CLAU) and transplantation of limbal cell sheets cultured from limbal biopsies, termed cultured limbal epithelial transplantation (CLET). In 2012, Sangwan and colleagues presented simple limbal epithelial transplantation (SLET), a novel transplantation technique that combines the benefits of CLAU and CLET and avoids the challenges associated with both. In SLET a small biopsy from the limbus of the healthy eye is divided and distributed over human amniotic membrane, which is placed on the affected cornea. Outgrowth occurs from each small explant and a complete corneal epithelium is typically formed within 2 weeks. Advantages of SLET include reduced risk of iatrogenic LSCD occurring in the healthy cornea at harvest; direct transfer circumventing the need for cell culture; and the opportunity to perform biopsy harvest and transplantation in one operation. Success so far using SLET is comparable with CLAU and CLET. Of note, 336 of 404 (83%) operations using SLET resulted in restoration of the corneal epithelium, whereas visual acuity improved in 258 of the 373 (69%) reported cases. This review summarizes the results of 31 studies published on SLET since 2012. Progress, advantages, challenges, and suggestions for future studies are presented.