Effect of dapagliflozin on 24-hour glycemic variables in Japanese patients with type 2 diabetes mellitus receiving basal insulin supported oral therapy (DBOT): a multicenter, randomized, open-label, parallel-group study.

INTRODUCTION: This study aimed to evaluate the impacts of dapagliflozin on 24-hour glucose variability and diabetes-related biochemical variables in Japanese patients with type 2 diabetes who had received basal insulin supported oral therapy (BOT). RESEARCH DESIGN AND METHODS: Changes in mean daily blood glucose level before and after 48-72 hours of add-on or no add-on of dapagliflozin (primary end point) and diabetes-related biochemical variables and major safety variables during the 12 weeks (secondary end point) were evaluated in the multicenter, randomized, two-arm, open-label, parallel-group comparison study. RESULTS: Among 36 participants, 18 were included in the no add-on group and 18 were included in the dapagliflozin add-on group. Age, gender, and body mass index were comparable between the groups. There were no changes in continuous glucose monitoring metrics in the no add-on group. In the dapagliflozin add-on group, mean glucose (183-156 mg/dL, p=0.001), maximum glucose (300-253, p<0.01), and SD glucose (57-45, p<0.05) decreased. Time in range increased (p<0.05), while time above the range decreased in the dapagliflozin add-on group but not in the no add-on group. After 12-week treatment with dapagliflozin add-on, 8-hydroxy-2'-deoxyguanosine (8OHdG), as well as hemoglobin A1c (HbA1c), decreased. CONCLUSIONS: This study showed that the mean daily blood glucose and other daily glucose profiles were amended after 48-72 hours of dapagliflozin add-on in Japanese patients with type 2 diabetes who received BOT. The diabetes-related biochemical variables such as HbA1c and urinary 8OHdG were also obtained during the 12 weeks of dapagliflozin add-on without major adverse events. A preferable 24-hour glucose profile in 'time in ranges' and an improvement in reactive oxygen species by dapagliflozin warrant us to evaluate these benefits in larger clinical studies. TRIAL REGISTRATION NUMBER: UMIN000019457.

Eicosapentaenoic Acid supplementation changes Fatty Acid composition and corrects endothelial dysfunction in hyperlipidemic patients.

We investigated the effects of purified eicosapentaenoic acid (EPA) on vascular endothelial function and free fatty acid composition in Japanese hyperlipidemic subjects. In subjects with hyperlipidemia (total cholesterol ≥220 mg/dL and/or triglycerides ≥150 mg/dL), lipid profile and forearm blood flow (FBF) during reactive hyperemia were determined before and 3 months after supplementation with 1800 mg/day EPA. Peak FBF during reactive hyperemia was lower in the hyperlipidemic group than the normolipidemic group. EPA supplementation did not change serum levels of total, HDL, or LDL cholesterol, apolipoproteins, remnant-like particle (RLP) cholesterol, RLP triglycerides, or malondialdehyde-modified LDL cholesterol. EPA supplementation did not change total free fatty acid levels in serum, but changed the fatty acid composition, with increased EPA and decreased linoleic acid, γ-linolenic acid, and dihomo-γ-linolenic acid. EPA supplementation recovered peak FBF after 3 months. Peak FBF recovery was correlated positively with EPA and EPA/arachidonic acid levels and correlated inversely with dihomo-γ-linolenic acid. EPA supplementation restores endothelium-dependent vasodilatation in hyperlipidemic patients despite having no effect on serum cholesterol and triglyceride patterns. These results suggest that EPA supplementation may improve vascular function at least partly via changes in fatty acid composition.

Impaired glucose tolerance, but not impaired fasting glucose, underlies left ventricular diastolic dysfunction.

OBJECTIVE: Glucose intolerance is recognized as a predictor of congestive heart failure (CHF). However, the association of postprandial hyperglycemia or fasting hyperglycemia with CHF has not been clarified. We determined the impact of the total spectrum of glucose abnormalities on left ventricular (LV) geometry and diastolic function. RESEARCH DESIGN AND METHODS: Two hundred and eighty-seven Japanese subjects who visited the university hospital to be checked for glucose intolerance or known type 2 diabetes were consecutively recruited. Participants underwent an oral glucose tolerance test if they had no history of diabetes, and LV geometry and LV systolic and diastolic function were analyzed by Doppler echocardiography. RESULTS: The frequency of LV diastolic dysfunction in subjects with normal glucose tolerance, impaired fasting glucose (IFG), impaired glucose tolerance (IGT), newly detected diabetes, and known diabetes were 13, 22, 50, 51, and 61%, respectively (χ(2) = 54.2, P < 0.0001). IGT was a predictor for LV diastolic dysfunction after adjusting for age, sex, systolic blood pressure, and heart rate (odds ratio 3.43 [95% CI 1.09-11.2]), but IFG was not (0.49 [0.06-3.08]). IGT was a predictor after adjusting for established CHF risk factors but was no longer significant after adjusting for BMI and homeostasis model assessment of insulin resistance. CONCLUSIONS: In this hospital-based registry of subjects without CHF, the prevalence of LV diastolic dysfunction was higher in subjects with IGT but not in those with IFG. Results suggest that IGT, as well as newly detected and known diabetes, could be linked to an increased risk of cardiovascular events, partly through LV diastolic dysfunction.

Cilostazol, a phosphodiesterase inhibitor, reduces microalbuminuria in the insulin-resistant Otsuka Long-Evans Tokushima Fatty rat.

We evaluated association between hyperinsulinemia/insulin resistance and microalbuminuria in the insulin-resistant Otsuka Long-Evans Tokushima Fatty (OLETF) rat. OLETF rats showed glomerular hyperfiltration (an increase in creatinine clearance and a decrease in fractional excretion of Na) and microalbuminuria at the insulin-resistant prediabetic stage, and both were related to expression of transforming growth factor (TGF)-beta(1) and extracellular matrix protein such as fibronectin and collagen (a(1)) IV. Cilostazol, a selective type III cyclic nucleotide phosphodiesterase (PDE) inhibitor, normalized glomerular hyperfiltration and microalbuminuria with a parallel decline of TGF-beta(1) and extracellular matrix protein mRNA expression. Cilostazol may be beneficial to lessen early glomerular nephropathy in a state of hyperinsulinemia/insulin resistance.

Fluvastatin improves endothelial dysfunction in overweight postmenopausal women through small dense low-density lipoprotein reduction.

Small dense low-density lipoprotein (sdLDL), which are often associated with obesity, are considered as the most atherogenic and have been shown to impair endothelial function. It is not known whether reduction of sdLDL by pharmacological intervention can improve endothelial function. Thirty-four consecutive postmenopausal women with >/=5.70 mmol/L total cholesterol were placed into either an overweight (body mass index [BMI] >/= 25.0, n = 22) or a normal-weight (BMI < 25.0, n = 12) group, and forearm blood flow (FBF) was measured using strain-gauge plethysmography during reactive hyperemia before and after fluvastatin treatment. At baseline, the peak FBF during reactive hyperemia in the overweight group was less than that in the normal-weight group (mean +/- SD, 13.6 +/- 4.4 v 22.2 +/- 4.0 mL/min/100 mL, P <.01). The maximal FBF after nitroglycerin was similar in both groups. In the stepwise multiple regression analysis, only the concentration of sdLDL was the predictor for peak FBF (standard coefficient = -0.517, P =.0115). The nonsignificant parameters for the correlations in the model were age, BMI, systolic blood pressure, the homeostasis model assessment of insulin resistance (HOMA-IR), hemoglobin A(1c) (HbA(1c)), and LDL-cholesterol. Fluvastatin treatment was associated with the recovery of the peak FBF in the overweight group but it did not influence that of the normal-weight group. Changes in sdLDL fractions by fluvastatin correlated well with the peak FBF recovery. These results suggested that an increased sdLDL was linked to endothelial dysfunction in overweight postmenopausal women and fluvastatin treatment improved endothelial dysfunction by decreasing the atherogenic sdLDL fraction in this population.

Hypoadiponectinemia is closely linked to endothelial dysfunction in man.

Vascular endothelial dysfunction has been demonstrated in overweight or obese patients, but the molecular basis for this link has not been clarified. We asked what the relationship was between adiponectin, an adipose-specific molecule, and endothelial function. Forearm blood flow (FBF) was measured during reactive hyperemia by using strain-gauge plethysmography in 76 Japanese subjects without a history of cardiovascular or cerebrovascular disease, diabetes mellitus, hepatic, or renal disease. The peak FBF and total reactive hyperemic flow [flow debt repayment (FDR)] during reactive hyperemia were correlated with waist circumference (r = -0.418 and -0.414, respectively) and body mass index (r = -0.597 and -0.626, respectively). After correcting for age, gender, and body mass index, the peak FBF was correlated with systolic blood pressure (r = -0.294; P = 0.010), free fatty acid (FFA) (r = -0.331; P = 0.004), and adiponectin in log 10 (r = 0.492; P < 0.001), and FDR was correlated with adiponectin in log 10 (r = 0.462; P = 0.001). In stepwise multiple regression analyses, predictive variables for peak FBF were adiponectin in log 10 (r = 0.468) and FFA (r = -0.292; r(2) = 0.487; P < 0.0001); and predictive variables for FDR were adiponectin in log 10 (r = 0.474) and FFA (r = -0.275; r(2) = 0.346, P < 0.0001). Endothelial function was impaired in proportion to the severity of obesity, and the level of severity was closely related to plasma adiponectin levels. Adiponectin may play a protective role against the atherosclerotic vascular change, and loss of effects enhances endothelial dysfunction, as in obese people.

Evidence for a deficient pancreatic beta-cell response in a rat model of hyperthyroidism.

To clarify mechanism behind the abnormal glucose tolerance, observed in hyperthyroidism, we studied genomic and nongenomic effects of thyroid hormone on insulin secretion using a rat model of hyperthyroidism. Male Sprague-Dawley rats were intraperitoneally injected with vehicle, low (100 microg/kg) or high dose (600 microg/kg) of thyroxin (T(4)) for 2 weeks. Rats treated with high dose, but not low dose, of T(4), showed an increase in serum T(3) levels, and a decrease in body weight as compared to control rats. In rats treated with either dose of T(4), fasting blood glucose levels were increased, but serum insulin levels were similar to those of controls. After an oral glucose load, blood glucose levels were increased in rats treated with high dose, but not low dose, of T(4). Serum insulin levels after the oral glucose load were decreased in rats treated with either dose of T(4). After an intravenous glucose load, blood glucose levels were comparable among groups, but serum insulin levels tended to be low in T(4)-treated rats. Steady-state blood glucose levels were comparable among groups. The insulin secretory responses to high glucose (20mM) or arginine (10mM) of the isolated pancreas was decreased in rats treated with high dose, but not low dose, of T(4). Mean insulin secretory response to glucose and arginine were decreased by 40.1% and by 60.4% in high-dose-T(4)-treated rats. Addition of T(3) in the perfusion medium decreased glucose-induced insulin release. Ratios of proinsulin mRNA levels to beta-actin mRNA were decreased in the islets of T(4)-treated rats (0.45 +/- 0.07 vs control 0.61 +/- 0.03, p < 0.05). Levels of TR (thyroid hormone nuclear receptor) alpha1 + cErb Aalpha2 mRNA, but not TRbeta1, were decreased in the pancreatic islets of T(4)-treated rats. Calculated islet area was increased, but the number of beta-cells determined immunohistochemically was not increased in T(4)-treated rats, nor the volume density of insulin positive islets. We concluded that a deficient pancreatic beta-cell response to glucose, rather than insulin resistance, was responsible for abnormal glucose tolerance in this model of hyperthyroidism. Thyroid hormone causes a decrease in glucose-induced insulin secretion. We observed nongenomic and genomic effects of thyroid hormone on glucose-induced insulin secretion.