Endothelin-1 induces lipolysis through activation of the GC/cGMP/Ca2+/ERK/CaMKIII pathway in 3T3-L1 adipocytes

Lipid droplet deposition in the regenerating liver: A promoter, inhibitor, or bystander?

Liver regeneration (LR) is a complex process involving intricate networks of cellular connections, cytokines, and growth factors. During the early stages of LR, hepatocytes accumulate lipids, primarily triacylglycerol, and cholesterol esters, in the lipid droplets. Although it is widely accepted that this phenomenon contributes to LR, the impact of lipid droplet deposition on LR remains a matter of debate. Some studies have suggested that lipid droplet deposition has no effect or may even be detrimental to LR. This review article focuses on transient regeneration-associated steatosis and its relationship with the liver regenerative response.

Potential lipolytic regulators derived from natural products as effective approaches to treat obesity

Epidemic obesity is contributing to increases in the prevalence of obesity-related metabolic diseases and has, therefore, become an important public health problem. Adipose tissue is a vital energy storage organ that regulates whole-body energy metabolism. Triglyceride degradation in adipocytes is called lipolysis. It is closely tied to obesity and the metabolic disorders associated with it. Various natural products such as flavonoids, alkaloids, and terpenoids regulate lipolysis and can promote weight loss or improve obesity-related metabolic conditions. It is important to identify the specific secondary metabolites that are most effective at reducing weight and the health risks associated with obesity and lipolysis regulation. The aims of this review were to identify, categorize, and clarify the modes of action of a wide diversity of plant secondary metabolites that have demonstrated prophylactic and therapeutic efficacy against obesity by regulating lipolysis. The present review explores the regulatory mechanisms of lipolysis and summarizes the effects and modes of action of various natural products on this process. We propose that the discovery and development of natural product-based lipolysis regulators could diminish the risks associated with obesity and certain metabolic conditions.

Dual endothelin receptor antagonism increases resting energy expenditure in people with increased adiposity

Increased adiposity is associated with dysregulation of the endothelin system, both of which increase the risk of cardiovascular disease (CVD). Preclinical data indicate that endothelin dysregulation also reduces resting energy expenditure (REE). The objective was to test the hypothesis that endothelin receptor antagonism will increase REE in people with obesity compared with healthy weight individuals. Using a double blind, placebo-controlled, crossover design, 32 participants [healthy weight (HW): n = 16, BMI: 21.3 ± 2.8 kg/m2, age: 26 ± 7 yr and overweight/obese (OB): n = 16, BMI: 33.5 ± 9.5 kg/m2, age: 31 ± 6 yr] were randomized to receive either 125 mg of bosentan (ETA/B antagonism) or placebo twice per day for 3 days. Breath-by-breath gas exchange data were collected and REE was assessed by indirect calorimetry. Venous blood samples were analyzed for concentrations of endothelin-1 (ET-1). Treatment with bosentan increased plasma ET-1 in both OB and HW groups. Within the OB group, the changes in absolute REE (PLA: -77.6 ± 127.6 vs. BOS: 72.2 ± 146.6 kcal/day; P = 0.046). The change in REE was not different following either treatment in the HW group. Overall, absolute plasma concentrations of ET-1 following treatment with bosentan were significantly associated with kcal/day of fat (r = 0.488, P = 0.005), percentage of fat utilization (r = 0.415, P = 0.020), and inversely associated with the percentage of carbohydrates (r = -0.419, P = 0.019), and respiratory exchange ratio (r = -0.407, P = 0.023). Taken together, these results suggest that modulation of the endothelin system may represent a novel therapeutic approach to increase both resting metabolism and caloric expenditure, and reduce CVD risk in people with increased adiposity.NEW & NOTEWORTHY Findings from our current translational investigation demonstrate that dual endothelin A/B receptor antagonism increases total REE in overweight/obese individuals. These results suggest that modulation of the endothelin system may represent a novel therapeutic target to increase both resting metabolism and caloric expenditure, enhance weight loss, and reduce CVD risk in seemingly healthy individuals with elevated adiposity.