The differentiation of the adipocyte and insulin sensitivity itself is affected by a caspase-1-dependent IL-1β-mediated mechanism. Mice fed a high

fat diet have increased caspase-1 and elevated levels of IL-1β. In contrast, caspase-1-deficient mice have decreased body fat and improved insulin sensitivity 86. In vivo, treatment of obese mice with a caspase-1 inhibitor significantly increases their insulin sensitivity 86. Calorimetry analysis revealed higher fat oxidation rates in caspase-1-deficient animals, and adipocytes from caspase-1-deficient mice or mice deficient in NLRP3 are more metabolically active ex vivo with higher insulin sensitivity and increased production of adiponectin this website as compared with adipocytes from wild-type mice. Gene expression for PPARγ and GLUT4 was also increased in fat from caspase-1- or NLRP3-deficient mice. In the ob/ob obese mouse, fat tissue reveals higher caspase-1 activity with elevated production of active IL-1β. Thus, in addition to blocking IL-1β in type 2 diabetes, targeting IL-1β in pre-diabetic persons with metabolic syndrome should correct some of the abnormalities. These studies are consistent with those reported Selleckchem CH5424802 by Vandanmagsar et al. 89. In those studies, a reduction in adipose tissue expression of NLRP3 was observed

in obese persons WT 2 diabetes following calorie restriction and exercise-mediated weight loss. Not unexpectedly, there was improved insulin sensitivity. Similar to the studies by Stienstra et al. 86, NLRP3-deficient mice did not show obesity-induced inflammasome activation PtdIns(3,4)P2 in fat depots 89. Collectively, both studies 86, 89 establish that caspase-1-dependent cytokines

play an important and possibly causative role in obesity-induced inflammation and insulin resistance. The first clinical proof of a role for IL-1 in the pathogenesis of type 2 diabetes was a randomized, placebo-controlled study of anakinra for 13 wk. In that study, improved insulin production and glycemic control was observed in anakinra-treated patients 90. The fall in glycated hemoglobin was nearly 0.5% lower than that in placebo-treated patients. In addition to improved glycemic control, C-peptide levels increased and the ratio of proinsulin to insulin decreased, both indicators of improved β-cell function. Not unexpectedly, serum IL-6 and CRP levels decreased significantly. In the 39 wk following the 13- wk course of anakinra, patients who responded to anakinra used 66% less insulin to obtain the same glycemic control as compared with baseline requirements 91. The proinsulin to insulin ratio also improved.