Androgens trigger different growth responses in genetically identical human hair follicles in organ culture that reflect their epigenetic diversity in life.

Male sex hormones-androgens-regulate male physique development. Without androgen signaling, genetic males appear female. During puberty, increasing androgens harness the hair follicle's unique regenerative ability to replace many tiny vellus hairs with larger, darker terminal hairs ( e.g., beard). Follicle response is epigenetically varied: some remain unaffected ( e.g., eyelashes) or are inhibited, causing balding. How sex steroid hormones alter such developmental processes is unclear, despite high incidences of hormone-driven cancer, hirsutism, and alopecia. Unfortunately, existing development models are not androgen sensitive. Here, we use hair follicles to establish an androgen-responsive human organ culture model. We show that women's intermediate facial follicles respond to men's higher androgen levels by synthesizing more hair over several days, unlike donor-matched, androgen-insensitive, terminal follicles. We demonstrate that androgen receptors-androgen-activated gene transcription regulators-are required and are present in vivo within these follicles. This is the first human organ that involves multiple cell types that responds appropriately to hormones in prolonged culture, in a way which mirrors its natural behavior. Thus, intermediate hair follicles offer a hormone-switchable human model with exceptional, unique availability of genetically identical, but epigenetically hormone-insensitive, terminal follicles. This should enable advances in understanding sex steroid hormone signaling, gene regulation, and developmental and regenerative systems and facilitate better therapies for hormone-dependent disorders.-Miranda, B. H., Charlesworth, M. R., Tobin, D. J., Sharpe, D. T., Randall, V. A. Androgens trigger different growth responses in genetically identical human hair follicles in organ culture that reflect their epigenetic diversity in life.

Bone morphogenetic protein signaling suppresses wound-induced skin repair by inhibiting keratinocyte proliferation and migration.

Bone morphogenetic protein (BMP) signaling plays a key role in the control of skin development and postnatal remodeling by regulating keratinocyte proliferation, differentiation, and apoptosis. To study the role of BMPs in wound-induced epidermal repair, we used transgenic mice overexpressing the BMP downstream component Smad1 under the control of a K14 promoter as an in vivo model, as well as ex vivo and in vitro assays. K14-caSmad1 (transgenic mice overexpressing a constitutively active form of Smad1 under K14 promoter) mice exhibited retarded wound healing associated with significant inhibition of proliferation and increased apoptosis in healing wound epithelium. Furthermore, microarray and quantitative real-time reverse-transcriptase-PCR (qRT-PCR) analyses revealed decreased expression of a number of cytoskeletal/cell motility-associated genes including wound-associated keratins (Krt16, Krt17) and Myosin VA (Myo5a), in the epidermis of K14-caSmad1 mice versus wild-type (WT) controls during wound healing. BMP treatment significantly inhibited keratinocyte migration ex vivo, and primary keratinocytes of K14-caSmad1 mice showed retarded migration compared with WT controls. Finally, small interfering RNA (siRNA)-mediated silencing of BMPR-1B in primary mouse keratinocytes accelerated cell migration and was associated with increased expression of Krt16, Krt17, and Myo5a compared with controls. Thus, this study demonstrates that BMPs inhibit keratinocyte proliferation, cytoskeletal organization, and migration in regenerating skin epithelium during wound healing, and raises a possibility for using BMP antagonists for the management of chronic wounds.

Effects of oestrogen agonists on human dermal fibroblasts in an in vitro wounding assay.

Oestrogen and dehydroepiandrosterone (DHEA) improve wound healing, but circulating levels decline significantly with age. Recently, the selective oestrogen receptor modulators (SERMs) tamoxifen and raloxifene have been shown to improve age-associated impaired wound healing. Therefore, we have evaluated the effects of 17beta-oestradiol, ER alpha and ER beta agonists, tamoxifen, raloxifene and DHEA on human dermal fibroblasts using an in vitro wound assay. An ER alpha agonist, 17beta-oestradiol and DHEA all significantly accelerated cell migration; the DHEA effect was blocked with an aromatase inhibitor. Tamoxifen, raloxifene and DHEA all significantly increased DNA synthesis; the DHEA stimulatory effect was reversed by an aromatase inhibitor. This study demonstrates that 17beta-oestradiol, an ER alpha agonist, tamoxifen, raloxifene and DHEA (following conversion to oestrogen) all have significant effects on human fibroblasts, the key mesenchymal cell involved in the wound healing process. Further understanding of the mechanisms involved may have important implications for the management of age-related impaired wound healing.

Differing responses of human follicular and nonfollicular scalp cells in an in vitro wound healing assay: effects of estrogen on vascular endothelial growth factor secretion.

Improved wound healing of hairy skin may involve mesenchymal hair follicle cells with stem cell potential and enhancement by estrogen therapy. How estrogen affects follicular dermal papilla (DP) and dermal sheath (DS) cells in wound healing is unknown. Therefore, a comparison of estradiol action on DP, DS, and corresponding interfollicular dermal fibroblasts (DF) in a scratch-wound assay was performed using matching primary cultures established from female temporo-occipital scalp. All three cell types expressed mRNA transcripts and protein for estrogen receptors alpha (ERalpha) and beta (ERbeta). DF ERalpha transcripts were half that of DP and one-third of DS cells, while DF ERbeta transcripts were two-thirds of DP and DS cells. In the scratch-wound assay all three cells types migrated at similar rates, but only the rate of DF was enhanced by estradiol. Mechanical wounding increased DNA synthesis rates of all three cell types and increased the secretion of collagen by DF and DS cells. All three secreted similar basal levels of vascular endothelial growth factor (VEGF), which was increased by wounding DF and DS cells, but not DP cells. DP cells required estradiol to increase VEGF secretion; by contrast VEGF secretion was decreased by estradiol in wounded DS cells. These results highlight differences in the responses of DF, DP, and DS cells to estradiol in a scratch-wound assay, providing further support for the dichotomy of cellular functions in the hair follicle. Further understanding of the role of estrogen in cutaneous wound healing may have important implications for the management of chronic wounds and scarring.

Magnetic resonance imaging and explantation investigation of long-term silicone gel implant integrity.

BACKGROUND: Information about silicone gel implant longevity is sparse. Magnetic resonance imaging studies have superseded explantation studies in the search for data on their long-term integrity. Unfortunately, the majority of studies are based predominantly on second-generation implant cohorts. Although magnetic resonance imaging is acknowledged to be the best imaging modality, the results of any study are entirely dependent on its ability to differentiate ruptured from intact implants. METHODS: A single, textured, third-generation implant type was chosen, to reduce the number of variables. The largest cohort of patients in our database had subglandular Mentor Siltex gel implants (Mentor Medical Systems, Santa Barbara, Calif.). They were contacted and offered a magnetic resonance imaging scan. All patients with at least one radiologically ruptured implant were then offered explantation. RESULTS: One hundred forty-nine patients with bilateral subglandular implants (median +/- SD age, 8.9 +/- 2.3; range, 4.8 to 13.5 years) were imaged and reported by two independent radiologists. Twenty-three patients were reported to have 33 radiologically ruptured implants. Twenty-one patients (30 radiologically ruptured implants) agreed to explantation. Statistical analysis using maximum likelihood estimation of survival curve for cross-sectional data suggests that implant rupture starts at 6 to 7 years and that by 13 years approximately 11.8 percent of implants will have ruptured. CONCLUSION: Although these results cannot necessarily be extrapolated to other implant types and manufacturers, they provide further information about the natural history of implant integrity, better enabling us to counsel prospective and current implant recipients.

Epidemiology and outcome analysis of 208 children with burns attending an emergency department.

OBJECTIVE: The purpose of this study was to prospectively study all burns attending a single inner city emergency department (ED) to establish epidemiological burn patterns and final outcomes for thermal injuries affecting children. DESIGN AND SETTING: A 12-month prospective study of all burns involving children (ages, 0-16 years) presenting to a single ED serving approximately 500,000 people. RESULTS: Two hundred eight children with burns attended the ED. The average patient age was 5 years, with most cases involving infants and young children. Fifty one percent of injuries were scalds, and 36% were contact burns. Burn size varied from 1% body surface area to 23% body surface area. First aid had not been administered in one third of cases before attendance, and 87% of patients had received no analgesia. Final outcomes were as follows: 5% of patients were discharged from the ED with no further follow-up. Twenty three percent of patients were instructed to attend their general practitioner for follow-up, and 58% were instructed to attend the ED clinic for review. Four percent of patients were reviewed in the plastic surgery dressing clinic, 7% were admitted to the plastic surgery ward, and 3% of patients were transferred to a burn center. In total, 3% of patients required burn excision and skin grafting for their burns. There were no deaths. CONCLUSIONS: Many pediatric burns are appropriately managed in the ED without the need for burn center care. Although the mortality from burn injury in children may have fallen in recent decades, problems persist in terms of small burns that can be associated with long-standing morbidity. Education and prevention programs are still required at all levels to help address the problem of childhood burns.

Quantifying collagen type in mature burn scars: a novel approach using histology and digital image analysis.

Using Herovici staining and digital image analysis, we have studied the collagen subtype and fiber orientation in mature burn scars. These techniques have shown mature burn scars to have increased type I/type III collagen ratios compared with normal skin. Additionally, the collagen orientation of burn scars has been shown to be thickened, tightly packed, and lacking the "basket weave" appearance of normal skin specimens. These techniques allow the differentiation of type I collagen from type III collagen, the assessment of collagen orientation, and the analysis of scar architecture in terms of epidermis and papillary/reticular dermis contribution. These findings are important clinically because collagen subtype and fiber orientation may predict future scar activity. Any attempt to modify the scarring process can be directly measured and compared using this easily reproducible technique.

Bilateral pyoderma gangrenosum complicating minimal access cranial suspension face lift.

We present the case of a previously healthy 53-year-old woman upon whom a minimal access cranial suspension (MACS) face lift and bilateral upper and lower blepharoplasty were performed. Her preauricular wounds recurrently broke down postoperatively, and after surgically excluding stitch granuloma, a diagnosis of pyoderma gangrenosum was made. The wound breakdown resolved with topical steroid treatment. Our case highlights the need to be aware of pyoderma gangrenosum to avoid unnecessary surgery.