Obesogenic and diabetogenic effects of high-calorie nutrition require adipocyte BK channels:Adipocyte BK protects from overwhelming BW gain

Elevated adipose tissue expression of the Ca2+- and voltage-activated K+ (BK) channel was identified in morbidly obese men carrying a BK gene variant supporting the hypothesis that K+ channels affect metabolic responses of fat cells to nutrients. To establish the role of endogenous BKs for fat cell maturation, storage of excess dietary fat and body-weight (BW) gain we studied a gene-targeted mouse model with a global ablation of the BK channel (BKL1/L1) and adipocyte-specific BK-deficient (adipoqBKL1/L2) mice. Global BK deficiency afforded protection from high-fat-diet (HFD) induced BW gain and excessive fat accumulation. Expansion of white adipose tissue-derived epididymal BKL1/L1 pre-adipocytes and their differentiation to lipid-filled mature adipocytes in vitro, however, were improved. Moreover, BW gain and total fat masses of usually super-obese ob/ob mice were significantly attenuated in the absence of BK together supporting a central or peripheral role for BKs in the regulatory system that controls adipose tissue and weight. Accordingly, HFD-fed adipoqBKL1/L2 mutants presented with a reduced total BW and overall body fat mass, smaller adipocytes and reduced leptin levels. Protection from pathologic weight gain in the absence of adipocyte BKs was beneficial for glucose handling and related to an increase in body core temperature due to higher levels of uncoupling protein 1 as well as low abundance of the proinflammatory interleukin-6 as a common risk factor for diabetes and metabolic abnormalities. This suggests that adipocyte BK activity is at least partially responsible for excessive BW gain under high-caloric conditions suggesting BK channels as promising drug targets for pharmacotherapy of metabolic disorders and obesity

Disease Progression and Age as Factors Underlying Multimorbidity in Patients with COPD:Results from COSYCONET

Background: Multimorbidity plays an important role in chronic obstructive pulmonary disease (COPD) but is also a feature of ageing. We estimated to what extent increases in the prevalence of multimorbidity over time are attributable to COPD progression compared to increasing patient age. Methods: Patients with COPD from the long-term COSYCONET (COPD and Systemic Consequences - Comorbidities Network) cohort with four follow-up visits were included in this analysis. At each visit, symptoms, exacerbation history, quality of life and lung function were assessed, along with the comorbidities heart failure (HF), coronary artery disease (CAD), peripheral arterial disease (PAD), hypertension, sleep apnea, diabetes mellitus, hyperlipidemia, hyperuricemia and osteoporosis. Using longitudinal logistic regression analysis, we determined what proportion of the increase in the prevalence of comorbidities could be attributed to patients' age or to the progression of COPD over visits. Results: Of 2030 patients at baseline, 878 completed four follow-up visits (up to 4.5 years). CAD prevalence increased over time, with similar effects attributable to the 4.5-year follow-up, used as indicator of COPD progression, and to a 5-year increase in patients' age. The prevalence of HF, diabetes, hyperlipidemia, hyperuricemia, osteoporosis and sleep apnea showed stronger contributions of COPD progression than of age; in contrast, age dominated for hypertension and PAD. There were different relationships to patients' characteristics including BMI and sex. The results were not critically dependent on the duration of COPD prior to enrolment, or the inclusion of patients with all four follow-up visits vs those attending only at least one of them. Conclusion: Analyzing the increasing prevalence of multimorbidity in COPD over time, we separated age-independent contributions, probably reflecting intrinsic COPD-related disease progression, from age-dependent contributions. This distinction might be useful for the individual assessment of disease progression in COPD

An autocrine lactate loop mediates insulin-dependent inhibition of lipolysis through GPR81.

Lactate is an important metabolic intermediate released by skeletal muscle and other organs including the adipose tissue, which converts glucose into lactate under the influence of insulin. Here we show that lactate activates the G protein-coupled receptor GPR81, which is expressed in adipocytes and mediates antilipolytic effects through G(i)-dependent inhibition of adenylyl cyclase. Using GPR81-deficient mice, we demonstrate that the receptor is not involved in the regulation of lipolysis during intensive exercise. However, insulin-induced inhibition of lipolysis and insulin-induced decrease in adipocyte cAMP levels were strongly reduced in mice lacking GPR81, although insulin-dependent release of lactate by adipocytes was comparable between wild-type and GPR81-deficient mice. Thus, lactate and its receptor GPR81 unexpectedly function in an autocrine and paracrine loop to mediate insulin-induced antilipolytic effects. These data show that lactate can directly modulate metabolic processes in a hormone-like manner, and they reveal a new mechanism underlying the antilipolytic effects of insulin