Leptin, a 16 kDa pleiotropic cytokine primarily expressed in adipose tissue, has been shown to cause multiple systemic biological actions. Recently, leptin has also been documented as an important component of the wound healing process and its receptor appears to be expressed in wound tissue. We have previously demonstrated that leptin is a potent angiogenic factor exerting direct effects on endothelial cells and that transcription of its encoding gene is regulated by hypoxia. Here, we hypothesize that leptin expression is acutely up-regulated in the ischemic tissue of experimental wounds. Using a combination of in situ hybridization and quantitative RT-PCR experiments, we show that leptin expression is rapidly and steadily up-regulated in skin tissue from incisional and excisional wounds. By immunohistochemistry, we demonstrate increased and sustained leptin protein levels in basal keratinocytes, blood vessel walls, and fibroblasts. To determine whether leptin is required for normal healing, excisional wounds were treated with neutralizing anti-leptin antibodies. This treatment markedly hampered healing progression and prevented wound closure and contraction. Finally, a transient rise in circulating blood leptin levels was detected within the first 24 h after inflicting the injury; we present evidence suggesting that this elevation is due to increased leptin production at the ischemic wound site. We conclude that leptin is acutely up-regulated in the injured skin and propose that this local production of leptin serves a critical functional role as an autocrine/paracrine regulator of normal wound healing.
Observational studies suggest that obese men have a lower risk of incident prostate cancer, but an increased risk of advanced and fatal cancers. These observations could be due to confounding, detection bias, or a biological effect of obesity. Genetic studies are less susceptible to confounding than observational epidemiology and can suggest how associations between phenotypes (such as obesity) and diseases arise. To determine whether the associations between obesity and prostate cancer are causal, we conducted a genetic association study of the relationship between a single nucleotide polymorphism known to be associated with obesity (FTO rs9939609) and prostate cancer. Data are from a population-based sample of 1550 screen-detected prostate cancers, 1815 age- and general practice matched controls with unrestricted prostate specific antigen (PSA) values and 1175 low-PSA controls (PSA <0.5 ng/ml). The rs9939609 A allele, which was associated with higher BMI in the sample, was inversely associated with overall (odds ratio (OR) versus all controls = 0.93; 95% confidence interval (CI): 0.85–1.02 p = 0.12 per allele) and low-grade (OR = 0.90; 0.81–0.99 p = 0.03 per allele) prostate cancer risk, but positively associated with high-grade cancer among cases (OR high- versus low-grade cancer = 1.16; 0.99–1.37 p = 0.07 per allele). Although evidence for these effects was weak, they are consistent with observational data based on BMI phenotypes and suggest that the observed association between obesity and prostate cancer is not due to confounding. Further research should confirm these findings, extend them to other BMI-related genetic variants and determine whether they are due to detection bias or obesity-related hormonal changes.Trial RegistrationControlled-Trials.com ISRCTN20141297
Evidence from laboratory studies suggests that chronic inflammation plays an important role in prostate cancer aetiology. This has resulted in speculation that nonsteroidal anti-inflammatory drugs may protect against prostate cancer development. We analysed data from a cross-sectional case-control study (n cases 5 1,016; n controls 5 5,043), nested within a UK-wide population-based study that used prostate specific antigen (PSA) testing for identification of asymptomatic prostate cancers, to investigate the relationship of aspirin, nonsteroidal anti-inflammatory drug (NSAID) and paracetamol use with prostate cancer. In conditional logistic regression models accounting for stratum matching on age (5-year age bands) and recruitment centre, use of non-aspirin NSAIDs [odds ratio (OR) 5 1.32; 95% confidence interval (CI): 1.04-1.67] or all NSAIDs (OR 5 1.25; 95% CI 5 1.07-1.47) were positively associated with prostate cancer. There were weaker, not conventionally statistically significant, positive associations of aspirin (OR 5 1.13; 95% CI 5 0.94-1.36) and paracetamol (OR 5 1.20; 95% CI 5 0.90-1.60) with prostate cancer. Mutual adjustment for aspirin, non-aspirin NSAIDs or paracetamol made little difference to these results. There was no evidence of confounding by age, family history of prostate cancer, body mass index or self-reported diabetes. Aspirin, NSAID and paracetamol use were associated with reduced serum PSA concentrations amongst controls. Our findings do not support the hypothesis that NSAIDs reduce the risk of PSA-detected prostate cancer. Our conclusions are unlikely to be influenced by PSA detection bias because the inverse associations of aspirin, NSAID and paracetamol use with serum PSA would have attenuated (not generated) the observed positive associations.
Elderly are more prone to develop hypoglycemia or miss meals. Repaglinide and nateglinide are suggested to have glucose-dependent insulinotropic effect. The aim of the present work was to test the effect of both drugs on serum glucose and insulin levels in fasting elderly diabetic patients. Eight elderly diabetics underwent a fixed dose single blinded, placebo controlled, six period, cross-over study at the Department of Geriatrics and Gerontology -University hospital. Patients received either repaglinide 2 mg, nateglinide 120 mg or a placebo, both under fasting and non-fasting states. Serum glucose and insulin were measured at 30 min intervals for four hours, following drug or placebo administration. None of the eight patients developed hypoglycemia under the fasting state in response to repaglinide and only one patient developed mild hypoglycemia (3.7 mmol/L) under the fasting state in response to nateglinide. Area under the serum insulin concentration-time curve was significantly lower (p = 0.039) in the fasting state, compared to the non-fasting state, in response to repaglinide, but not to nateglinide. The present study suggests that in case of elderly diabetic patients, who may miss meals, repaglinide is a safe alternative to other antidiabetics. As for nateglinide, further studies are required.
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