Estrogen promotes cutaneous wound healing via estrogen receptor β independent of its antiinflammatory activities

Post-menopausal women have an increased risk of developing a number of degenerative pathological conditions, linked by the common theme of excessive inflammation. Systemic estrogen replacement (in the form of hormone replacement therapy) is able to accelerate healing of acute cutaneous wounds in elderly females, linked to its potent antiinflammatory activity. However, in contrast to many other age-associated pathologies, the detailed mechanisms through which estrogen modulates skin repair, particularly the cell type–specific role of the two estrogen receptors, ERα and ERβ, has yet to be determined. Here, we use pharmacological activation and genetic deletion to investigate the role of both ERα and ERβ in cutaneous tissue repair. Unexpectedly, we report that exogenous estrogen replacement to ovariectomised mice in the absence of ERβ actually delayed wound healing. Moreover, healing in epidermal-specific ERβ null mice (K14-cre/ERβL2/L2) largely resembled that in global ERβ null mice. Thus, the beneficial effects of estrogen on skin wound healing are mediated by epidermal ERβ, in marked contrast to most other tissues in the body where ERα is predominant. Surprisingly, agonists to both ERα and ERβ are potently antiinflammatory during skin repair, indicating clear uncoupling of inflammation and overall efficiency of repair. Thus, estrogen-mediated antiinflammatory activity is not the principal factor in accelerated wound healing

Nanoscale structure of type I collagen fibrils: Quantitative measurement of D‐spacing

This article details a quantitative method to measure the D‐periodic spacing of type I collagen fibrils using atomic force microscopy coupled with analysis using a two‐dimensional fast fourier transform approach. Instrument calibration, data sampling and data analysis are discussed and comparisons of the data to the complementary methods of electron microscopy and X‐ray scattering are made. Examples of the application of this new approach to the analysis of type I collagen morphology in disease models of estrogen depletion and osteogenesis imperfecta (OI) are provided. We demonstrate that it is the D‐spacing distribution, not the D‐spacing mean, that showed statistically significant differences in estrogen depletion associated with early stage osteoporosis and OI. The ability to quantitatively characterize nanoscale morphological features of type I collagen fibrils will provide important structural information regarding type I collagen in many research areas, including tissue aging and disease, tissue engineering, and gene knockout studies. Furthermore, we also envision potential clinical applications including evaluation of tissue collagen integrity under the impact of diseases or drug treatments. The distribution of Type I collagen fibril D‐spacing provides important morphological information regarding Type I collagen in diseases such as early stages of osteoporosis and osteogenesis Imperfecta . In this article, the authors use Atomic Force Microscopy (AFM) imaging combined with two Dimensional Fast Fourier Transform (2D FFT) analysis to quantitatively assess Type I collagen fibril D‐spacing. This methodology allows imaging and characterization of Type I collagen constituted biological tissues, hydrogels, and other collagen based biomaterials.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94732/1/117_ftp.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/94732/2/biot_201200174_sm_suppinfo.pd