Deregulation of epidermal stem cell niche contributes to pathogenesis of nonhealing venous ulcers.

The epidermis is maintained by epidermal stem cells (ESCs) that reside in distinct niches and contribute to homeostasis and wound closure. Keratinocytes at the nonhealing edges of venous ulcers (VUs) are healing-incompetent, hyperproliferative, and nonmigratory, suggesting deregulation of ESCs. To date, genes which regulate ESC niches have been studied in mice only. Utilizing microarray analysis of VU nonhealing edges, we identified changes in expression of genes harboring regulation of ESCs and their fate. In a prospective clinical study of 10 VUs, we confirmed suppression of the bone morphogenetic protein receptor (BMPR) and GATA binding protein 3 (GATA3) as well as inhibitors of DNA-binding proteins 2 and 4 (ID2 and ID4). We also found decreased levels of phosphorylated glycogen synthase kinase 3 (GSK3), nuclear presence of ß-catenin, and overexpression of its transcriptional target, c-myc, indicating activation of the Wnt pathway. Additionally, we found down-regulation of leucine-rich repeats and immunoglobulin-like domains protein 1 (LRIG1), a gene important for maintaining ESCs in a quiescent state, and absence of keratin 15 (K15), a marker of the basal stem cell compartment suggesting local depletion of ESCs. Our study shows that loss of genes important for regulation of ESCs and their fate along with activation of ß-catenin and c-myc in the VU may contribute to ESC deprivation and a hyperproliferative, nonmigratory healing incapable wound edge.

Effective method to remove wound bacteria: comparison of various debridement modalities in an in vivo porcine model.

BACKGROUND: Debridement is one of the crucial steps for successful wound care. In addition to removing necrotic tissue, debridement has been shown to reduce wound-associated bacteria that delay healing. Using an in vivo porcine model, we compared the effects of various methods of debridement, including hydrosurgery and plasma-mediated bipolar radiofrequency ablation (PBRA), on bacterial removal and wound healing. METHODS: One hundred thirty-five deep dermal wounds were inoculated with methicillin resistant Staphylococcus aureus (MRSA) and covered with a polyurethane dressing for 48 h to allow for biofilm formation. Wounds were then treated with either PBRA (at two settings), hydrosurgery, sharp debridement, or no debridement. Biopsies were collected for microbiology and histologic assessment on d 0, 2, 9, and 21 post-treatment. RESULTS: All treatment groups showed a statistically significant reduction in MRSA counts relative to no debridement at all times points (P < 0.05). PBRA at a maximum setting had the lowest MRSA counts at all recovery times and, compared with all other treatment groups, a statistically significant difference was observed on d 21 (P < 0.05). No detrimental effects on the healing process were noted with any of the debridement methods. CONCLUSION: While sharp debridement has been established as the traditional gold standard for rapid removal of necrotic, infected tissue, our results suggest that novel debridement modalities show clinical promise for the treatment of chronic ulcers and burn wounds, especially when bacteria are present.

Excision and grafting of palmoplantar keratoderma.

Palmoplantar keratodermas may present to the clinician with an extremely broad series of clinical findings. Management has also taken on a wide variety of medical and surgical modalities. The literature seems to provide evidence that optimum management consists of surgical excision with skin grafting. It is believed that this will eliminate all of the underlying tissue and associated skin appendages, which are believed to be the source of this abnormal skin entity. We present a case of a patient in which tangential excision with delayed split-thickness skin grafting was performed after initial application of an acellular dermal matrix (Integra). Unfortunately, there was nearly immediate recurrence of this disease, and we, therefore, suggest a more aggressive approach to the initial excision.

A Case of Circumscribed Scalp Morphea with Perineural Lymphocytes on Pathology.

Scalp morphea presents as a scarring alopecia in en coup du sabre pattern. We report an unusual presentation of a round hairless patch of morphea on the occipital scalp present for 15 years. The scalp lesion aligned with 2 other hyperpigmented lesions of biopsy-proven morphea in the lower back. Pathology of horizontal sections from the scalp lesion showed follicular dropout, thickening of the collagen bundles, and preserved eccrine and follicular structures. Marked lymphocytic perineural infiltrate, a reported clue to the diagnosis of scalp morphea, contributed to the diagnosis. This case is unusual due to its rare clinical presentation. It also highlights the importance of recognizing histopathological clues for the diagnosis of uncommon scalp disorders.

Epithelialization in Wound Healing: A Comprehensive Review.

Significance: Keratinocytes, a major cellular component of the epidermis, are responsible for restoring the epidermis after injury through a process termed epithelialization. This review will focus on the pivotal role of keratinocytes in epithelialization, including cellular processes and mechanisms of their regulation during re-epithelialization, and their cross talk with other cell types participating in wound healing. Recent Advances: Discoveries in epidermal stem cells, keratinocyte immune function, and the role of the epidermis as an independent neuroendocrine organ will be reviewed. Novel mechanisms of gene expression regulation important for re-epithelialization, including microRNAs and histone modifications, will also be discussed. Critical Issues: Epithelialization is an essential component of wound healing used as a defining parameter of a successful wound closure. A wound cannot be considered healed in the absence of re-epithelialization. The epithelialization process is impaired in all types of chronic wounds. Future Directions: A comprehensive understanding of the epithelialization process will ultimately lead to the development of novel therapeutic approaches to promote wound closure.

Nonsurgical therapy for hair loss.

This article is an update of the currently available options for medical therapies to treat androgenetic alopecia in men and women. Emerging novel therapeutic modalities with potential for treating these patients are discussed. Because androgenetic alopecia is progressive in nature, stabilization of the process using medical therapy is an important adjunct to any surgical hair-restoration plan.

Interactions of methicillin resistant Staphylococcus aureus USA300 and Pseudomonas aeruginosa in polymicrobial wound infection.

Understanding the pathology resulting from Staphylococcus aureus and Pseudomonas aeruginosa polymicrobial wound infections is of great importance due to their ubiquitous nature, increasing prevalence, growing resistance to antimicrobial agents, and ability to delay healing. Methicillin-resistant S. aureus USA300 is the leading cause of community-associated bacterial infections resulting in increased morbidity and mortality. We utilized a well-established porcine partial thickness wound healing model to study the synergistic effects of USA300 and P. aeruginosa on wound healing. Wound re-epithelialization was significantly delayed by mixed-species biofilms through suppression of keratinocyte growth factor 1. Pseudomonas showed an inhibitory effect on USA300 growth in vitro while both species co-existed in cutaneous wounds in vivo. Polymicrobial wound infection in the presence of P. aeruginosa resulted in induced expression of USA300 virulence factors Panton-Valentine leukocidin and α-hemolysin. These results provide evidence for the interaction of bacterial species within mixed-species biofilms in vivo and for the first time, the contribution of virulence factors to the severity of polymicrobial wound infections.