Rationale Abdominal aortic aneurysm (AAA) is a complex disease with both genetic and environmental risk factors. Together, 6 previously identified risk loci only explain a small proportion of the heritability of AAA. Objective To identify additional AAA risk loci using data from all available genome-wide association studies (GWAS). Methods and Results Through a meta-analysis of 6 GWAS datasets and a validation study totalling 10,204 cases and 107,766 controls we identified 4 new AAA risk loci: 1q32.3 (SMYD2), 13q12.11 (LINC00540), 20q13.12 (near PCIF1/MMP9/ZNF335), and 21q22.2 (ERG). In various database searches we observed no new associations between the lead AAA SNPs and coronary artery disease, blood pressure, lipids or diabetes. Network analyses identified ERG, IL6R and LDLR as modifiers of MMP9, with a direct interaction between ERG and MMP9. Conclusions The 4 new risk loci for AAA appear to be specific for AAA compared with other cardiovascular diseases and related traits suggesting that traditional cardiovascular risk factor management may only have limited value in preventing the progression of aneurysmal disease.
Ghrelin is an orexigenic peptide and a growth hormone (GH) secretagogue. Secretory dynamics of ghrelin have not been characterized in adolescents with anorexia nervosa (AN). We hypothesized that, compared with healthy adolescents, girls with AN would have increased ghrelin concentrations measured over 12 h of nocturnal sampling from increased basal and pulsatile secretion, and endogenous ghrelin would independently predict GH and cortisol. We examined ghrelin concentration and secretory dynamics in 22 girls with AN and 18 healthy adolescents 12-18 yr old. Associations between ghrelin, various hormones, and measures of insulin resistance were examined. On Cluster analysis, girls with AN had higher ghrelin concentrations than controls, including total area under the curve (AUC) (P ϭ 0.002), nadir (P ϭ 0.0006), and valley levels (P ϭ 0.002). On deconvolution analysis, secretory burst amplitude (P ϭ 0.03) and burst mass (P ϭ 0.04) were higher in AN, resulting in higher pulsatile (P ϭ 0.05) and total ghrelin secretion (P ϭ 0.03). Fasting ghrelin independently predicted GH burst frequency (r ϭ 0.44, P ϭ 0.005). The nutritional markers body mass index and body fat predicted postglucose and valley ghrelin but not fasting levels. Ghrelin parameters were inversely associated with fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), leptin, and IGF-I. HOMA-IR was the most significant predictor of most ghrelin parameters. Valley ghrelin independently predicted cortisol burst frequency (52% of variability), and ghrelin parameters independently predicted total triiodothyronine and LH levels. Higher ghrelin concentrations in adolescents with AN are a consequence of increased secretory burst mass and amplitude. The most important predictor of ghrelin concentration is insulin resistance, and ghrelin in turn predicts GH and cortisol burst frequency. growth hormone; cortisol; total triiodothyronine; estradiol; luteinizing hormone; insulin resistance GHRELIN, A 28-AMINO ACID PEPTIDE, is a growth hormone (GH) secretagogue (2, 4, 25, 26, 50 -53) that is also orexigenic (40,56). It is unknown whether elevated ghrelin values are an important contributing factor to the elevated GH levels that occur in anorexia nervosa (AN), a unique model of chronic undernutrition. We have demonstrated higher fasting ghrelin levels in adolescent girls with AN compared with healthy adolescents and higher nadir ghrelin levels following an oral glucose load (36). Girls with AN also have higher GH concentrations, a consequence of increased basal GH secretion and secretory burst frequency (33). Similarly, elevated ghrelin (21, 39) and GH concentrations (47, 49) have been reported in adult women with AN. Negative feedback from low IGF-I levels has been hypothesized to cause increased GH secretion, and the relationship between ghrelin and GH secretion in AN has not been explored.Administration of a single dose of intravenous ghrelin causes an increase in GH secretion in both rodent models (51, 66) and healthy adults (4, 50, 52). Howe...
Leptin, an adipocytokine that suppresses appetite and may regulate neuroendocrine pathways, is low in undernourished states like anorexia nervosa (AN). Although leptin exhibits pulsatility, secretory characteristics have not been well described in adolescents and in AN, and the contribution of hypoleptinemia to increased growth hormone (GH) and cortisol in AN has not been explored. We hypothesized that hypoleptinemia in AN reflects decreased basal and pulsatile secretion and may predict increased GH and cortisol levels. Sampling for leptin, GH, cortisol, and ghrelin was performed every 30 min (from 2000 to 0800) in 23 AN and 21 controls 12-18 yr old, and data were analyzed using Cluster and deconvolution methods. Estradiol, thyroid hormones, and body composition were measured. AN girls had lower pulsatile and total leptin secretion than controls (P < 0.0001) subsequent to decreased burst mass (P < 0.0001) and basal secretion (P = 0.02). Nutritional markers predicted leptin characteristics. In a regression model including BMI, body fat, and ghrelin, leptin independently predicted GH burst interval and frequency. Valley leptin contributed to 56% of the variability in GH burst interval, and basal leptin and fasting ghrelin contributed to 42% of variability in burst frequency. Pulsatile leptin independently predicted urine free cortisol/creatinine (15% of variability). Valley leptin predicted cortisol half-life (22% of variability). Leptin predicted estradiol and thyroid hormone levels. In conclusion, hypoleptinemia in AN is subsequent to decreased basal and pulsatile secretion and nutritionally regulated. Leptin predicts GH and cortisol parameters and with ghrelin predicts GH burst frequency. Low leptin and high ghrelin may be dual stimuli for high GH concentrations in undernutrition.
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Pericytes are mural cells that support and stabilise the microvasculature, and are present in all vascular beds. Pericyte-endothelial cell crosstalk is essential in both remodelling and quiescent vasculature, and this complex interaction is often disrupted in disease states. Pericyte loss is believed to be an early hallmark of diabetes-associated microvascular disease, including retinopathy and nephropathy. Here we review the current literature defining pericyte biology in the context of diabetes-associated vascular disease, with a particular focus on whether pericytes contribute actively to disease progression. We also speculate regarding the role of pericytes in the recovery from macrovascular complications, such as critical limb ischaemia. It becomes clear that dysfunctional pericytes are likely to actively induce disease progression by causing vasoconstriction and basement membrane thickening, resulting in tissue ischaemia. Moreover, their altered interactions with endothelial cells are likely to cause abnormal and inadequate neovascularisation in diverse vascular beds. Further research is needed to identify mechanisms by which pericyte function is altered by diabetes, with a view to developing therapeutic approaches that normalise vascular function and remodelling.
increased expression of APP and BACE1 and the production of Aβ peptides, whereas exogenous NO reduces APP, BACE1, and Aβ levels in cerebral microvessels (23). Thus, there appears to be an interesting reciprocal connection between BACE1, APP processing, Aβ levels, and NO bioavailability. Hyperglycemia and hyperlipidemia increase BACE1 activity and Aβ peptide levels in tissues and plasma (24, 25), linking key metabolic disease markers with increased amyloid processing. Consequently, we hypothesized that the development of type 2 diabetes (T2D) and/or obesity elevates circulating Aβ levels, which in turn drives vascular dysfunction. We tested this hypothesis in 3 ways: firstly, by reducing BACE1 activity genetically and pharmacologically in mice and ascertaining how this modified diet-induced endothelial dysfunction; secondly, by increasing plasma Aβ levels, indirectly through overexpression of mutant human APP genes and directly by Aβ peptide infusion, to promote vascular dysfunction in mice; and thirdly, by cross-sectionally examining the association between plasma Aβ levels and endothelial function in patients with T2D.
Supracondylar fractures of the humerus are the commonest upper limb fractures in children, accounting for up to 70% of all paediatric elbow fractures [Wilson MJ, Hunter JB. Supracondylar fractures of the humerus in children--wire removal in the outpatient setting. Injury Extra 2006 Aug;37(8):313-315] and are often complicated by neurovascular injury. Much confusion surrounds the management of the child with a "pink pulseless hand" post-fracture reduction and several treatment options have been proposed including observation, immediate exploration and angiography. The literature contains a number of case series with variable follow-up. Both angiography and colour duplex ultrasound provide little benefit in the management of these patients. A child with a pink pulseless hand post-fracture reduction can be managed expectantly unless additional signs of vascular compromise develop, in which case exploration should be undertaken.
Accurate incidence figures of an occult contralateral inguinal hernia will enhance the pre-operative information given to patients and may impact on resource allocation and planning theatre logistics. Finding and repairing an occult contralateral hernia at the time of TAPP has the distinct advantage that it saves the patient from further symptoms and from another operation with its associated potential morbidity.
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