Street-based adolescents at high risk of HIV in Ukraine

BACKGROUND: Ukraine has the highest HIV prevalence in Europe, with young people disproportionately represented among populations at high risk. One particularly vulnerable group comprises adolescents who live or work on the streets. This study aimed to measure the extent and distribution of HIV risk behaviours among street-based adolescents in four Ukrainian cities as part of a regional UNICEF HIV prevention programme for most-at-risk adolescents. METHODS: A cross-sectional behavioural survey was conducted of 805 adolescents (aged 10-19 years) in the cities of Kiev, Donetsk, Dnepropetrovsk and Nikolaev. Using location-based network and convenience sampling, 200 adolescents were reached in each site and were administered a standardised questionnaire on drug use, sexual behaviour, condom use, HIV knowledge, access to prevention services, experience of violence and contact with state institutions and police. RESULTS: Considerable levels of HIV risk behaviour were found, including injecting drug use among 15.5% of the sample. Almost three-quarters of adolescents had experienced sexual debut, most before the age of 15 years. Male-to-male sexual behaviour was reported by just under 10% of boys. Condom use was low although varied by partner type. There were high rates of forced sex, and 75.5% of respondents reported police harassment. CONCLUSIONS: Street-based adolescents in Ukraine are at significant risk of contracting HIV due to involvement in injecting drug use and unprotected sex in personal and commercial exchanges, including male-to-male sex. This group initiates risk behaviours at early ages, and does not appear to have good access to prevention and other health services

Reduced adipose tissue oxygenation in human obesity evidence for rarefaction, macrophage chemotaxis, and inflammation without an angiogenic response

OBJECTIVE-Based on rodent studies, we examined the hypothesis that increased adipose tissue (AT) mass in obesity without an adequate support of vascularization might lead to hypoxia, macrophage infiltration, and inflammation. RESEARCH DESIGN AND METHODS-Oxygen partial pressure (AT pO 2) and AT temperature in abdominal AT (9 lean and 12 overweight/obese men and women) was measured by direct insertion of a polarographic Clark electrode. Body composition was measured by dual-energy X-ray absorptiometry, and insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp. Abdominal subcutaneous tissue was used for staining, quantitative RT-PCR, and chemokine secretion assay. RESULTS-AT pO 2 was lower in overweight/obese subjects than lean subjects (47 ± 10.6 vs. 55 ± 9.1 mmHg); however, this level of pO 2 did not activate the classic hypoxia targets (pyruvate dehydrogenase kinase and vascular endothelial growth factor [VEGF]). AT pO 2 was negatively correlated with percent body fat (R =-0.50, P \u3c 0.05). Compared with lean subjects, overweight/ obese subjects had 44% lower capillary density and 58% lower VEGF, suggesting AT rarefaction (capillary drop out). This might be due to lower peroxisome proliferator-activated receptor γ1 and higher collagen VI mRNA expression, which correlated with AT pO 2 (P \u3c 0.05). Of clinical importance, AT pO 2 negatively correlated with CD68 mRNA and macrophage inflammatory protein 1α secretion (R =-0.58, R =-0.79, P \u3c 0.05), suggesting that lower AT pO 2 could drive AT inflammation in obesity. CONCLUSIONS-Adipose tissue rarefaction might lie upstream of both low AT pO 2 and inflammation in obesity. These results suggest novel approaches to treat the dysfunctional AT found in obesity. © 2009 by the American Diabetes Association

Skeletal Muscle Mitochondrial Capacity and Insulin Resistance in Type 2 Diabetes

Maximal mitochondrial ATP synthesis, measured by dynamic 31P magnetic resonance spectroscopy, is reduced in type 2 diabetes but is not associated with insulin resistance

Dynamic changes in fat oxidation in human primary myocytes mirror metabolic characteristics of the donor

Metabolic flexibility of skeletal muscle, that is, the preference for fat oxidation (FOx) during fasting and for carbohydrate oxidation in response to insulin, is decreased during insulin resistance. The aim of this study was to test the hypothesis that the capacity of myotubes to oxidize fat in vitro reflects the donor’s metabolic characteristics. Insulin sensitivity (IS) and metabolic flexibility of 16 healthy, young male subjects was determined by euglycemic hyperinsulinemic clamp. Muscle samples were obtained from vastus lateralis, cultured, and differentiated into myotubes. In human myotubes in vitro, we measured suppressibility (glucose suppression of FOx) and adaptability (an increase in FOx in the presence of high palmitate concentration). We termed these dynamic changes in FOx metabolic switching. In vivo, metabolic flexibility was positively correlated with IS and maximal oxygen uptake and inversely correlated with percent body fat. In vitro suppressibility was inversely correlated with IS and metabolic flexibility and positively correlated with body fat and fasting FFA levels. Adaptability was negatively associated with percent body fat and fasting insulin and positively correlated with IS and metabolic flexibility. The interindividual variability in metabolic phenotypes was preserved in human myotubes separated from their neuroendocrine environment, which supports the hypothesis that metabolic switching is an intrinsic property of skeletal muscle