Malnourished mice fed an HFD developed obesity, glucose intolerance, and increased liver glucose output. TAU preserved only normal liver glucose control in RHT mice, an effect associated with increased liver p-AMPK content.

Background: Coronavirus disease 19 (COVID-19) can develop into a severe respiratory syndrome that results in up to 40% mortality. Acute lung inflammatory edema is a major pathological finding in autopsies explaining O2 diffusion failure and hypoxemia. Only dexamethasone has been shown to reduce mortality in severe cases, further supporting a role for inflammation in disease severity. SARS-CoV-2 enters cells employing angiotensin-converting enzyme 2 (ACE2) as a receptor, which is highly expressed in lung alveolar cells. ACE2 is one of the components of the cellular machinery that inactivates the potent inflammatory agent bradykinin, and SARS-CoV-2 infection could interfere with the catalytic activity of ACE2, leading to the accumulation of bradykinin. Methods: In this case control study, we tested two pharmacological inhibitors of the kinin–kallikrein system that are currently approved for the treatment of hereditary angioedema, icatibant, and inhibitor of C1 esterase/kallikrein, in a group of 30 patients with severe COVID-19. Results: Neither icatibant nor inhibitor of C1 esterase/kallikrein resulted in changes in time to clinical improvement. However, both compounds were safe and promoted the significant improvement of lung computed tomography scores and increased blood eosinophils, which are indicators of disease recovery. Conclusions: In this small cohort, we found evidence for safety and a beneficial role of pharmacological inhibition of the kinin–kallikrein system in two markers that indicate improved disease recovery.

Feeding behavior is a major determinant of body composition, adiposity, and glucose homeostasis. Both obesity and malnutrition are risk factors for the metabolic syndrome and are associated with altered food intake. Here we assessed the effects of taurine (TAU) supplementation upon adiposity, food intake, and central insulin signaling in malnourished mice fed on a high-fat diet (HFD). Weaned male C57BL/6 mice were fed a control (14% protein-C) or a protein-restricted (6% protein-R) diet. After 6 weeks, both groups received or not HFD for 8 weeks (CH and RH). Half of the HFD groups were supplemented with 5% TAU (CHT and RHT). Both HFD groups were overweight and showed increased perigonadal and retroperitoneal fat pads. TAU supplementation attenuated obesity in CHT but not in RHT mice. HFD induced hypercholesterolemia and glucose intolerance, although only CH group presented fasting hyperglycemia. TAU supplementation also improved glucose homeostasis only in CHT mice. Western blot analysis showed a reduction of 55% in CH hypothalamic content of phosphorylated IRS-1 (pIRS-1) at basal condition compared with C. TAU treatment increased 35% Akt phosphorylation levels in CHT without modification in RHT hypothalamus. However, TAU supplementation did not alter hypothalamic pIRS-1 amount. CH and RH mice presented increased calorie intake that was normalized in CHT but not in RHT. In conclusion, mice fed on an HFD developed obesity, hypercholesterolemia, glucose intolerance, and increased calorie intake. TAU promoted increased hypothalamic insulin action only in CH mice which was linked to prevention of overfeeding, obesity, and glucose intolerance. Protein-restriction promoted metabolic damages that were not prevented by TAU supplementation.

Recently, we demonstrated that the hypothalamic S1PR1/STAT3 axis plays a critical role in the control of food consumption and energy expenditure in rodents. Here, we found that reduction of hypothalamic S1PR1 expression occurs in an age-dependent manner, and was associated with defective thermogenic signaling and weight gain. To address the physiological relevance of these findings, we investigated the effects of chronic and acute exercise on the hypothalamic S1PR1/STAT3 axis. Chronic exercise increased S1PR1 expression and STAT3 phosphorylation in the hypothalamus, restoring the anorexigenic and thermogenic signals in middle-aged mice. Acutely, exercise increased sphingosine-1-phosphate (S1P) levels in the cerebrospinal fluid (CSF) of young rats, whereas the administration of CSF from exercised young rats into the hypothalamus of middle-aged rats at rest was sufficient to reduce the food intake. Finally, the intracerebroventricular (ICV) administration of S1PR1 activators, including the bioactive lipid molecule S1P, and pharmacological S1PR1 activator, SEW2871, induced a potent STAT3 phosphorylation and anorexigenic response in middle-aged rats. Overall, these results suggest that hypothalamic S1PR1 is important for the maintenance of energy balance and provide new insights into the mechanism by which exercise controls the anorexigenic and thermogenic signals in the central nervous system during the aging process.

No abstract