A recent study suggests that exogenous ghrelin administration might decrease renal sympathetic nerve activity in conscious rabbits. In the present study, we investigated whether ghrelin administration would attenuate left ventricular (LV) remodeling following myocardial infarction (MI) via the suppression of cardiac sympathetic activity. Ghrelin (100 μg/kg sc, twice daily, n = 15) or saline ( n = 15) were administered for 2 wk from the day after MI operation in Sprague-Dawley rats. The effects of ghrelin on cardiac remodeling were evaluated by echocardiographic, hemodynamic, histopathological, and gene analysis. In addition, before and after ghrelin (100 μg/kg sc, n = 6) was administered in conscious rats with MI, the autonomic nervous function was investigated by power spectral analysis obtained by a telemetry system. In ghrelin-treated rats, LV enlargement induced by MI was significantly attenuated compared with saline-treated rats. In addition, there was a substantial decrease in LV end-diastolic pressure and increases in the peak rate of the rise and fall of LV pressure in ghrelin-treated MI rats compared with saline-treated MI rats. Furthermore, ghrelin attenuated an increase in morphometrical collagen volume fraction in the noninfarct region, which was accompanied by the suppression of collagen I and III mRNA levels. Importantly, a 2-wk administration of ghrelin dramatically suppressed the MI-induced increase in heart rate and plasma norepinephrine concentration to the similar levels as in sham-operated controls. Moreover, acute administration of ghrelin to MI rats decreased the ratio of the low-to-high frequency spectra of heart rate variability ( P < 0.01). In conclusion, these data suggest the potential usefulness of ghrelin as a new cardioprotective hormone early after MI.
SummaryAtherosclerosis has been regarded as a form of chronic vascular inflammation. Numerous biomarkers associated with inflammation have been identified as novel targets to monitor atherosclerosis and cardiovascular risk. C-reactive protein (CRP) is one of the most actively studied and established inflammatory biomarkers for cardiovascular events. However, CRP response is triggered by many disorders unrelated to cardiovascular disease, which interferes with the clinical application. This review describes established and traditional inflammatory biomarkers including CRP as well as novel inflammatory biomarkers reflective of local atherosclerotic inflammation. In addition, we focus on the potential usefulness of inflammatory biomarkers in developing anti-atherosclerotic therapeutic approaches. (Int Heart J 2016; 57: 134-139)
BackgroundEndothelial dysfunction caused by increased oxidative stress is a critical initiator of macro- and micro-vascular disease development in diabetic patients. Ipragliflozin, a selective sodium-glucose cotransporter 2 (SGLT2) inhibitor, offers a novel approach for the treatment of diabetes by enhancing urinary glucose excretion. The aim of this study was to examine whether ipragliflozin attenuates endothelial dysfunction in diabetic mice.MethodsEight-week-old male C57BL/6 mice were treated with streptozotocin (150 mg/kg) by a single intraperitoneal injection to induce diabetes mellitus. At 3 days of injection, ipragliflozin (3 mg/kg/day) was administered via gavage for 3 weeks. Vascular function was assessed by isometric tension recording. Human umbilical vein endothelial cells (HUVEC) were used for in vitro experiments. RNA and protein expression were examined by quantitative RT-PCR (qPCR) and western blot, respectively. Oxidative stress was determined by measuring urine 8-hydroxy-2′-deoxyguanosine (8-OHdG) level.ResultsIpragliflozin administration significantly reduced blood glucose level (P < 0.001) and attenuated the impairment of endothelial function in diabetic mice, as determined by acetylcholine-dependent vasodilation (P < 0.001). Ipragliflozin did not alter metabolic parameters, such as body weight and food intake. Ipragliflozin administration ameliorated impaired phosphorylation of Akt and eNOSSer1177 in the abdominal aorta and reduced reactive oxygen species generation as determined by urinary excretion of 8-OHdG in diabetic mice. Furthermore, qPCR analyses demonstrated that ipragliflozin decreased the expression of inflammatory molecules [e.g., monocyte chemoattractant protein-1 (MCP-1) vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule (ICAM)-1] in the abdominal aorta (P < 0.05). In in vitro studies, incubation with methylglyoxal, one of the advanced glycation end products, significantly impaired phosphorylation of Akt and eNOSSer1177 (P < 0.01) and increased the expression of MCP-1, VCAM-1, and ICAM-1 in HUVEC.ConclusionIpragliflozin improved hyperglycemia and prevented the development of endothelial dysfunction under a hyperglycemic state, at least partially by attenuation of oxidative stress.
BackgroundIt is unknown whether canagliflozin, a selective sodium glucose co-transporter 2 inhibitor, reduces epicardial adipose tissue (EAT) thickness, which is associated with insulin resistance and is a risk factor for coronary artery disease.Methods and resultsWe administered 100 mg of canagliflozin for 6 months to 13 patients with type 2 diabetes mellitus. We evaluated glycemic control, visceral adipose tissue (VAT) area and subcutaneous adipose tissue (SAT) area, and skeletal muscle mass by using impedance methods, and EAT thickness by using echocardiography. Canagliflozin treatment for 6 months decreased hemoglobin A1c level from 7.1 ± 0.5% to 6.7 ± 0.6% (P < 0.05) and decreased EAT thickness from 9.3 ± 2.5 to 7.3 ± 2.0 mm (P < 0.001), along with a trend of decreasing VAT and SAT area. No association was found between any of these changes.ConclusionCanagliflozin reduced EAT thickness in patients with type 2 diabetes mellitus independent of its effect on lowering blood glucose, suggesting that canagliflozin may have an effect in preventing cardiovascular events in these patients (UMIN000021327).Electronic supplementary materialThe online version of this article (doi:10.1186/s13098-017-0275-4) contains supplementary material, which is available to authorized users.
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