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Abstract: Background: Early recognition of acute organ dysfunction in emergency department (ED) patients with suspected infection may help select patients at increased risk of mortality. The hematologic system is often overlooked in the evaluation and management of patients with infection because it is poorly circumscribed and serves a multitude of functions. Study Objectives: We examine the hypothesis that abnormalities in commonly and easily obtained markers of coagulation function (international normalized ratio [INR], partial thromboplastin time [PTT], and platelet count [PLT]) are associated with mortality in ED patients admitted to the hospital with suspected infection. Methods: Design: Secondary analysis of a prospective observational cohort study. Setting: Urban tertiary care university hospital with 50,000 annual ED visits. Patients: Included patients: adults (age 18 ≥ years) evaluated in the ED for a suspected infection, had an INR, PTT, and PLT obtained during the ED stay, admitted to the hospital. Excluded patients: on oral anticoagulant therapy, received heparin, or pre-existing severe liver disease. Results: There were 1688 patients included. The in-hospital mortality rate was 5.9%. After adjusting for elderly status, comorbid illness burden, and severity of illness, elevated INR was associated with a 2.9 (95% confidence interval [CI] 1.6–5.2) increased odds of death, and a low platelet count (< 150,000/uL) was associated with 2.0 (95% CI 1.2–3.3) increased odds of death. The C-statistic for the model was 0.80. Conclusion: We found an independent association between abnormalities in the coagulation system and mortality in ED patients with suspected infection. These findings underscore the close interaction between inflammation and coagulation and provide evidence that these simple laboratory tests should be routinely considered during the early evaluation of the infected patient. [Copyright &y& Elsevier]

Vascular smooth muscle cell (VSMC) proliferation and migration contribute significantly to atherosclerosis, postangioplasty restenosis, and transplant vasculopathy. Forkhead transcription factors belonging to the FoxO subfamily have been shown to inhibit growth and cell cycle progression in a variety of cell types. We hypothesized that forkhead proteins may play a role in VSMC biology. Under in vitro conditions, platelet-derived growth factor (PDGF)-BB, tumor necrosis factor-α, and insulin-like growth factor 1 stimulated phosphorylation of FoxO in human coronary artery smooth muscle cells via MEK½ and/or phosphatidylinositol 3-kinase-dependent signaling pathways. PDGF-BB, tumor necrosis factor-α, and insulin-like growth factor 1 treatment resulted in the nuclear exclusion of FoxO, whereas PDGF-BB alone down-regulated the FoxO target gene, p27 kip1, and enhanced cell survival and progression through the cell cycle. These effects were abrogated by overexpression of a constitutively active, phosphorylation-resistant mutant of the FoxO family member, TM-FKHRL1. The anti-proliferative effect of TM-FKHRL1 was partially reversed by small interfering RNA against p27kip1. In a rat balloon carotid arterial injury model, adenovirus-mediated gene transfer of FKHRL1 caused an increase in the expression of p27kip1 in the VSMC and inhibition of neointimal hyperplasia. These data suggest that FoxO activity inhibits VSMC proliferation and activation and that this signaling axis may represent a therapeutic target in vasculopathic disease states. [ABSTRACT FROM AUTHOR]

We have previously shown that targeted overexpression of the endogenous angiogenesis inhibitor thrombospondin-1 (TSP-1) in the epidermis prevented chronic ultraviolet B (UVB)-induced angiogenesis and cutaneous photodamage in mice, suggesting that angiogenesis plays a critical role in the mediation of UVB effects on the skin. Nevertheless, the molecular regulation of angiogenesis factors and inhibitors by acute UVB irradiation still remains to be elucidated. We performed quantitative analyses of cutaneous vascularity and of vascular endothelial growth factor (VEGF) and TSP-1 expression after acute UVB irradiation of mouse skin. Skin vascularity in the upper dermis was greatly increased until day 8 after a single dose of UVB irradiation (200 mJ per cm2) and associated with upregulation of VEGF mRNA expression, with downregulation of TSP-1 mRNA, and with protein expression in the hyperplastic epidermis. After 13 days, skin vascularity was normalized with downregulation of VEGF mRNA expression and upregulation of TSP-1 mRNA expression to the levels observed in non-UVB-irradiated skin. In contrast, the angiogenic UVB response was prolonged in TSP-1-deficient mice. We found a pronounced induction of the TSP-1 receptor CD36 in CD31-positive vessels on day 8 after UVB irradiation, associated with vascular endothelial cell apoptosis. These results demonstrate that acute UVB irradiation leads to a shift toward a proangiogenic environment and they suggest that the balance between VEGF and TSP-1 plays a critical role in the control of angiogenesis and vascular regression induced by acute UVB irradiation. [ABSTRACT FROM AUTHOR]

Hair growth is associated with pronounced vascular-endothelial-growth-factor-induced perifollicular angiogenesis, whereas the catagen regression phase is characterized by apoptosis-driven blood vessel regression. The biologic relevance of endogenous inhibitors of angiogenesis in the control of hair cycling, however, has remained unknown. We studied the expression and biologic role of the angiogenesis inhibitor thrombospondin-1 (TSP-1) during the induced adult hair follicle cycle in wild-type, TSP-1 deficient, and TSP-1 overexpressing transgenic mice. TSP-1 expression was absent from hair bulb and dermal papilla cells during early to mid-anagen but was highly upregulated throughout the catagen involution phase. In TSP-1 deficient mice, the follicle growth phase was significantly prolonged, associated with increased perifollicular vascularization and vascular proliferation. Conversely, hair follicle growth was delayed in K14/TSP-1 transgenic mice that expressed high levels of TSP-1 in outer root sheath keratinocytes, associated with reduced perifollicular vascularization. These effects were most probably mediated via its antiangiogenic effects because TSP-1 did not affect the growth of cultured murine vibrissae in the absence of a functional vascular system. These results identify a critical role of TSP-1 in the induction of anagen follicle involution, with potential implications for the therapeutic modulation of hair follicle growth. [ABSTRACT FROM AUTHOR]

Chronic ultraviolet-B irradiation of the skin results in epidermal hyperplasia, degradation of extracellular matrix molecules, and formation of wrinkles. To characterize the biologic role of the vascular system in the mediation of ultraviolet-B-induced skin damage, we performed quantitative analyses of cutaneous blood vessels of mice after 10 wk of ultraviolet-B irradiation. Skin vascularization was greatly increased after chronic ultraviolet-B exposure with a significant increase of both the number and the size of dermal blood vessels, associated with upregulation of vascular endothelial growth factor expression in the hyperplastic epidermis. To directly study whether inhibition of angiogenesis may diminish ultraviolet-B-induced cutaneous damage, wild-type and transgenic mice with skin-specific overexpression of the endogenous angiogenesis inhibitor thrombospondin-1 were subjected to the same ultraviolet-B irradiation regimen. Ultraviolet-B-irradiated thrombospondin-1 transgenic mice showed a significantly reduced skin vascularization, decreased endothelial cell proliferation, and increased endothelial cell apoptosis rates, compared with wild-type mice. Moreover, dermal photo-damage and wrinkle formation were greatly reduced in thrombospondin-1 transgenic mice. These results reveal an important role of the cutaneous vascular system in mediating ultraviolet-B-induced skin damage and suggest inhibition of angiogenesis as a potential new approach for the prevention of chronic cutaneous photo-damage. [ABSTRACT FROM AUTHOR]

Endothelial phenotypes are highly regulated in space and time by both transcriptional and post-transcriptional mechanisms. There is increasing evidence that the GATA family of transcription factors function as signal transducers, coupling changes in the extracellular environment to changes in downstream target gene expression. Here we show that human primary endothelial cells derived from large blood vessels express GATA2, -3, and -6. Of these factors, GATA3 was expressed at the highest levels. In DNA microarrays of human umbilical vein endothelial cells (HUVEC), small interfering RNA-mediated knockdown of GATA3 resulted in reduced expression of genes associated with angiogenesis, including Tie2. At a functional level, GATA3 knockdown inhibited angiopoietin (Ang)1-mediated but not vascular endothelial cell growth factor (VEGF)-mediated AKT signaling, cell migration, survival, and tube formation. In electrophoretic gel mobility shift assays and chromatin immunoprecipitation, GATA3 was shown to bind to regulatory regions within the 5'-untranslated region of the Tie2 gene. In co-immunoprecipitation and co-transfection assays, GATA3 and the Ets transcription factor, ELF 1, physically interacted and synergized to transactivate the Tie2 promoter. GATA3 knockdown blocked the ability of Ang1 to attenuate vascular endothelial cell growth factor stimulation of vascular cell adhesion molecule-1 expression and monocytic cell adhesion. Moreover, exposure of human umbilical vein endothelial cells to tumor necrosis factor-α resulted in marked down-regulation of GATA3 expression and reduction in Tie2 expression. Together, these findings suggest that GATA3 is indispensable for Ang-1-Tie2-mediated signaling in large vessel endothelial cells. [ABSTRACT FROM AUTHOR]

Hair follicle regeneration involves epithelial–mesenchymal interactions (EMIs) of follicular epithelial and dermal papilla (DP) cells. Co-grafting of those cellular components from mice allows complete hair reconstitution. However, regeneration of human hair in a similar manner has not been reported. Here, we investigated the possibility of cell-based hair generation from human cells. We found that DP-enriched cells (DPE) are more critical than epidermal cells in murine hair reconstitution on a cell number basis, and that murine DPE are also competent for hair regeneration with rat epidermal cells. Co-grafting of human keratinocytes derived from neonatal foreskins with murine DPE produced hair follicle-like structures consisting of multiple epidermal cell layers with a well-keratinized innermost region. Those structures expressed hair follicle-specific markers including hair keratin, and markers expressed during developmental stages. However, the lack of regular hair structures indicates abnormal folliculogenesis. Similar hair follicle-like structures were also generated with cultured human keratinocytes after the first passage, or with keratinocytes derived from adult foreskins, demonstrating that epidermal cells even at a mature stage can differentiate in response to inductive signals from DP cells. This study emphasizes the importance of EMI in follicular generation and the differentiation potential of epidermal keratinocytes.Journal of Investigative Dermatology (2007) 127, 2106–2115; doi:10.1038/sj.jid.5700823; published online 12 April 2007 [ABSTRACT FROM AUTHOR]