Statins may precipitate the onset of type 2 diabetes (T2D) in high-risk patients. In contrast, only the subset of individuals with insulin resistance and/or diabetes receives cardiovascular benefits with fibrates. In this context, previous observations from our laboratory suggested that atorvastatin induced an increase in visceral adipose tissue (VAT), whereas fenofibrate had the opposite effects in rabbits. Therefore, we determined the mass, morphology, and vascularization of VAT in New Zealand white rabbits (n = 6/group) that received 0.33 or 2.6 mg/kg/d of atorvastatin or fenofibrate, respectively, during 2 months. As expected, the cholesterol from the atorvastatin group was lower after treatment, while triglycerides decreased in the fenofibrate group. The mass of VAT from the fenofibrate group was 46% lower compared to the controls, meanwhile atorvastatin was associated with a larger diameter of adipocytes (+65%) than that of the control and fenofibrate groups. Fibroblast growth factor 2 ( FGF2) gene expression was lower in the fenofibrate group than in the control group (−54%). By contrast, vascular endothelial growth factor A (VEGF-A) gene expression in fenofibrate-treated rabbits was 110% higher than in the control group. In agreement with the gene expression, the marker of angiogenesis platelet endothelial cell adhesion molecule 1 was slightly but significantly higher (+10%) in rabbits treated with fenofibrate than in controls, as determined by immunohistochemistry. These results suggest that fenofibrate is associated with a favorable remodeling of VAT, that is, reduced mass and increased vascularization in normolipemic rabbits; in contrast, atorvastatin induced a nonfavorable remodeling of VAT. These results may be related to the cardiovascular benefits of fenofibrate and the increased risk of T2D in high-risk patients induced by atorvastatin.

Accumulating evidence indicates that insulin-mediated signaling in the brain may play important roles in regulating neuronal function. Alterations to insulin signaling are associated with the development of neurological disorders including Alzheimer's disease and Parkinson's disease. Also, hyperglycemia and insulin resistance have been associated with seizure activity and brain injury. In recent work, we found that insulin increased inhibitory GABA A -mediated tonic currents in the prefrontal cortex (PFC).In this work, we used local field potential recordings and calcium imaging to investigate the effect of insulin on seizure-like activity in PFC slices. Seizure-like events (SLEs) were induced by perfusing the slices with magnesium-free artificial cerebrospinal fluid (ACSF) containing the proconvulsive compound 4-aminopyridine (4-AP). We found that insulin decreased the frequency, amplitude, and duration of SLEs as well as the synchronic activity of PFC neurons evoked by 4-AP. These insulin effects were mediated by the PI3K/Akt signaling pathway and mimicked by gaboxadol (THIP), a δ GABA A receptor agonist. The effect of insulin on the number of SLEs was partially blocked by L-655,708, an inverse agonist with high selectivity for GABA A receptors containing the α5 subunit. Our results suggest that insulin reduces neuronal excitability by an increase of GABAergic tonic currents. The physiological relevance of these findings is discussed.

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Background Statins may precipitate the onset of type 2 diabetes (T2D) in high-risk patients. In contrast, only the subset of individuals with insulin resistance (IR) and/or diabetes receives cardiovascular benefits with fibrates. The mechanism responsible of such effects may be related with visceral adipose tissue (VAT). In this context, previous observations have suggested that atorvastatin induced an increase of VAT whereas fenofibrate had the opposite effects in rabbits. Purpose To determine the mass, morphology and vascularization of VAT in New Zealand white rabbits that received of atorvastatin or fenofibrate during two months. Methods New Zealand white rabbits (n=6 per group) received by oral gavage during 2 months, 0.33 mg/kg of atorvastatin or 2.6 mg/kg fenofibrate. The control group received 0.5 mL of vehicle. Plasma lipids were monitored. The visceral adipose tissue (VAT) was dissected and quantified. The expression of genes related with vascularization, VEGF-A and TGF-β, FGF2 as well as TNF-α were determined by qPCR in VAT. Histological slices were stained by hematoxilin and eosin to determine the size of adipocytes. The marker of angiogenesis, PECAM-1, was determined by immunohistochemistry. Results As expected, the cholesterol from atorvastatin was lower after treatment while triglycerides decreased in fenofibrate group. The mass of VAT from fenofibrate group was 46% lower compared with the controls meanwhile atorvastatin was associated with a larger diameter of adipocytes (+65%) than that of the control and fenofibrate groups. FGF2 gene expression was lower in fenofibrate than in control group (−54%). By contrast, VEGF-A gene expression in fenofibrate-treated rabbits was 110% higher than in control group. TGF-β and TNF-α remained comparable among groups. In agreement with the gene expression, the marker of angiogenesis PECAM-1 was slightly but significantly higher (+10%) in rabbits treated with fenofibrate than in controls, as determined by immunohistochemistry. Conclusion Fenofibrate enhanced the VEGF-A gene expression, PCAM-1 in VAT whereas decreased its total mass. In contrast, atorvastatin increased the adipocyte size without any effect on vascularization markers. These results suggest that fenofibrate is associated with a favorable remodeling of VAT, in contrast with atorvastatin, which induced a non-favorable remodeling of VAT. These results may be related with the cardiovascular benefits of fenofibrate and the increased risk of T2D in high-risk subjects induced by atorvastatin.