Comparative effects of insulin glulisine and lispro on postprandial plasma glucose and lipid profile in Japanese patients with type 2 diabetes mellitus.

OBJECTIVE: The control of postprandial plasma glucose (PPG) excursions is critical in the prevention of diabetic complications. Controversy remains on the differences in postprandial actions of insulin glulisine and lispro. The aim of this study was to define the differences in the efficacy of these two insulin analogues on PPG. METHODS: The study subjects were 20 in-hospital patients with type 2 diabetes mellitus (T2DM). Plasma glucose (PG) was tightly controlled with basal insulin and insulin glulisine or lispro, and then glulisine or lispro were switched to the other insulin analog every other day for 6 study days. PG was measured before breakfast and 0.5-, 1-, and 2 h-postprandial during the study. Postprandial plasma C-peptide and lipids were analyzed in the first 2 days of the study. Postprandial increments in each parameter were compared between glulisine and lispro. RESULTS: Whereas the median value of 0.5 h-Δ-PPG was comparable in glulisine and lispro, the 1 h-Δ-PPG was significantly lower with lispro than with glulisine (41 vs 53 mg/dl, respectively, p = 0.03). Similarly, the 2 h-Δ-PPG with lispro was 10 mg/dl lower than that with glulisine (35 vs 45 mg/dl, respectively, p = 0.05). In parallel with PPG, Δ-C-peptide at 1- and 2 h-postprandial were significantly lower with lispro than glulisine (0.50 vs 0.75 ng/ml, respectively, and 0.55 vs 0.75 ng/ml, respectively). The increment in LDL-C and HDL-C was significantly lower with lispro than with glulisine at 0.5 h-postprandial. CONCLUSION: Insulin lispro seems superior to glulisine in the control of PPG in Japanese patients with T2DM.

Cardiac overexpression of perilipin 2 induces atrial steatosis, connexin 43 remodeling, and atrial fibrillation in aged mice.

Atrial fibrillation (AF) is prevalent in patients with obesity and diabetes, and such patients often exhibit cardiac steatosis. Since the role of cardiac steatosis per se in the induction of AF has not been elucidated, the present study was designed to explore the relation between cardiac steatosis and AF. Transgenic (Tg) mice with cardiac-specific overexpression of perilipin 2 (PLIN2) were housed in the laboratory for more than 12 mo before the study. Electron microscopy of the atria of PLIN2-Tg mice showed accumulation of small lipid droplets around mitochondrial chains, and five- to ninefold greater atrial triacylglycerol (TAG) content compared with wild-type (WT) mice. Electrocardiography showed significantly longer RR intervals in PLIN2-Tg mice than in WT mice. Transesophageal electrical burst pacing resulted in significantly higher prevalence of sustained (>5 min) AF (69%) in PLIN2-Tg mice than in WT mice (24%), although it was comparable in younger (4-mo-old) mice. Connexin 43 (Cx43), a gap junction protein, was localized at the intercalated disks in WT atria but was heterogeneously distributed on the lateral side of cardiomyocytes in PLIN2-Tg atria. Langendorff-perfused hearts using the optical mapping technique showed slower and heterogeneous impulse propagation in PLIN2-Tg atria compared with WT atria. Cardiac overexpression of hormone-sensitive lipase in PLIN2-Tg mice resulted in atrial TAG depletion and amelioration of AF susceptibility. The results suggest that PLIN2-induced steatosis is associated with Cx43 remodeling, impaired conduction propagation, and higher incidence of AF in aged mice. Therapies targeting cardiac steatosis could be potentially beneficial against AF in patients with obesity or diabetes.

Cardiac overexpression of perilipin 2 induces dynamic steatosis: prevention by hormone-sensitive lipase.

Cardiac intracellular lipid accumulation (steatosis) is a pathophysiological phenomenon observed in starvation and diabetes mellitus. Perilipin 2 (PLIN2) is a lipid droplet (LD)-associated protein expressed in nonadipose tissues, including the heart. To explore the pathophysiological function of myocardial PLIN2, we generated transgenic (Tg) mice by cardiac-specific overexpression of PLIN2. Tg hearts showed accumulation of numerous small LDs associated with mitochondrial chains and high cardiac triacylglycerol (TAG) content [8-fold greater than wild-type (WT) mice]. Despite massive steatosis, cardiac uptake of glucose, fatty acids and VLDL, systolic function, and expression of metabolic genes were comparable in the two genotypes, and no morphological changes were observed by electron microscopy in the Tg hearts. Twenty-four hours of fasting markedly reduced steatosis in Tg hearts, whereas WT mice showed accumulation of LDs. Although activity of adipose triglyceride lipase in heart homogenate was comparable between WT and Tg mice, activity of hormone-sensitive lipase (HSL) was 40-50% less in Tg than WT mice under both feeding and fasting conditions, suggesting interference of PLIN2 with HSL. Mice generated through crossing of PLIN2-Tg mice and HSL-Tg mice showed cardiac-specific HSL overexpression and complete lack of steatosis. The results suggest that cardiac PLIN2 plays an important pathophysiological role in the development of dynamic steatosis and that the latter was prevented by upregulation of intracellular lipases, including HSL.

On the top of ARB N/L type Ca channel blocker leads to less elevation of aldosterone.

The activation of the renin-angiotensin system (RAS) is one of the unfavourable characteristics of calcium channel blocker (CCB). N type calcium channel is thought to be involved in renin gene transcription and adrenal aldosterone release. Accordingly, N/L type CCB has a possibility of less elevation of plasma aldosterone concentrations (PAC) among CCBs. In a monotherapy study, we had already demonstrated that N/L type CCB leads to less activation of the RAS compared with L type CCB. The objective of this study is to substantiate the hypothesis that at the condition of additive administration on the top of an angiotensin receptor blocker (ARB), still N/L type CCB leads to less elevation of PAC compared with L type one. Subjects were 60 hypertensives administered with valsartan. As an open label study, amlodipine (L type) or cilnidipine (N/L type) were administered on the top of valsartan (ARB) in a cross-over manner. Results were as follows (valsartan+amlodipine compared with valsartan+cilnidipine): systolic blood pressure (SBP)/diastolic blood pressure (DBP) (mmHg): 132±10/76±10 compared with 131±10/77±9, P=0.95/0.48, plasma renin activity (PRA) (ng/ml·h): 2.41±2.67 compared with 2.00±1.50 P=0.20, PAC (pg/ml): 77.3±31.0 compared with 67.4±24.8, P<0.05, urinary albumin excretion (UAE) (mg/gCr): 105.9±216.1 compared with 73.9±122.2, P<0.05. Thus, PAC at cilnidipine was significantly lower than those at amlodipine in spite of the comparable BP reductions. Besides, UAE was significantly lower at cilnidipine. In conclusion, on the top of the ARB, it is suggested that cilnidipine administration might lead to less elevation of PAC and reduction in UAE compared with amlodipine.

Intrathoracic Benign Goiter Imaged by 18F-FDG-PET: A Case Report.

A 55-year-old woman was referred for a suspicion of mediastinal tumor through plain X-ray photography (X-P). Magnetic resonance imaging (MRI) revealed a 3 cm diameter tumor which seemed to connect to the thyroid and projected into the mediastinum. A fine needle aspiration biopsy was tried but could not reach a conclusive diagnosis. Thereby, fluorine-18-fluorodeoxyglucose positron emission tomography (F-FDG-PET) was performed and a high accumulation was revealed with standardized uptake value (SUV) of 3.8. Thus, the right lobe excision procedure was enforced. The obtained tumor was continuous to the right lobe as expected. Microscopically, the encapsulated tumor consisted of atypical large-sized follicles without malignant characteristics. Thus, histological diagnosis was follicular thyroid adenoma.Thus, follicular adenoma of thyroid could present negative iodine-123-radioisotope (I-RI) uptake and positive F-FDG-PET accumulation.

Determinants of plasma renin activity: role of a human renin gene variant as a genetic factor.

The plasma renin activity (PRA) is affected by a number of environmental factors. However, significant heritability has been shown for the activity. A hypothesis that a candidate regulatory single-nucleotide polymorphism, C-5312T, of human renin gene should have a significant effect on PRA was elucidated and updating of independent determinants of PRA was attempted. Cross sectional study. Outpatient study. We enrolled consecutive 810 subjects who had consulted our hospitals for lifestyle-related diseases. Genotypes were assayed with genomic DNA for C-5312T. Among the genetic variants, the difference of PRA was evaluated. Monovariate linear regression analysis was performed to test the correlation between PRA and clinical variables. Finally, stepwise multiple regression analysis was performed to evaluate the independent determinants. On comparing 2 genotype groups, CC/CT and T allele homozygote, the geometric means of PRA were 0.778 and 0.941 ng/ml/h, respectively (F = 5.992, P = 0.015). Monovariate linear regression analysis revealed that a number of variables have a significant correlation with the activity, including urinary salt excretion. A stepwise multivariate regression analysis revealed that renin C-5312T variant (TT) is one of the independent determinants of PRA. Thus, for the first time, a human renin gene variant was associated with a significant increase in PRA as a genetic factor and the independent determinants for the activity were updated including genetic factor.

Genetic variant of the renin-angiotensin system and prevalence of type 2 diabetes mellitus: a modest but significant effect of aldosterone synthase.

Recent genome-wide association studies have identified multiple variants that confer risk of type 2 diabetes mellitus (DM). However, established associations explain only a part of the heritability. Thus, even at the genome-wide association studies era, candidate gene approach should be still useful. Recent interventional studies against the renin-angiotensin system (RAS) showed reduction in new onset of DM, implying the system is involved in the onset. We substantiated the hypothesis that genetic variants of RAS have significant association with prevalence of DM. We enrolled to the study consecutive 782 subjects who had consulted our hospitals for mainly lifestyle related diseases. They consisted of 282 (36.1 %) diabetes cases. Genotypes were assayed with genomic DNA for conventional four genes of the RAS, i.e., angiotensin converting enzyme (ACE) insertion/deletion variant, angiotensinogen (AGT) M235T variant, angiotensin II type I receptor (AT1) A1166C variant, and aldosterone synthase (CYP11B2) C-344T variant. Association between the genetic variants of the RAS and prevalence of type 2 DM was tested. A significant association of DM and CYP11B2 genotype was obtained. There was no significant association between DM and ACE, AGT and AT1 variants. A multivariate logistic regression showed that age, gender, and CYP11B2 genotype were independent factors for association to diabetes, the DM risk of CC/CT to TT being 1.40 (95 % CI 1.04-1.90, p = 0.029). Thus, it is concluded that a genetic variant of the RAS should have a modest but significant impact on the onset of type 2 diabetes mellitus.

Differential effects of α-glucosidase inhibitors on postprandial plasma glucose and lipid profile in patients with type 2 diabetes under control with insulin lispro mix 50/50.

BACKGROUND: The additive effect of α-glucosidase inhibitors (α-GIs) was investigated in patients with type 2 diabetes (T2D) under control with rapid-acting insulin analog. SUBJECTS AND METHODS: Thirty-six poorly controlled T2D patients were recruited, and plasma glucose (PG) was controlled by three times daily injection of insulin lispro mix 50/50 (Mix50) to maintain fasting PG <130 mg/dL and 2-h postprandial PG (PPG) <180 mg/dL. Another group of 20 patients was randomly assigned to either 0.3 mg of voglibose or 50 mg of miglitol, which was administered at breakfast every other day. Another group of 16 patients was assigned to a crossover study, in which each α-GI was switched every day during the 6-day study. PPG, C-peptide, and lipid profile were analyzed. RESULTS: The addition of voglibose had no effect on PPG, but miglitol blunted the PPG rise and significantly decreased 1-h and 2-h postprandial C-peptide levels compared with Mix50 alone. In addition, miglitol significantly decreased the 1-h postprandial triglyceride rise and the remnant-like particle-cholesterol rise, while it increased the 1-h postprandial high-density lipoprotein-cholesterol and apolipoprotein A-I levels in the crossover study. CONCLUSIONS: Miglitol appears to have rapid action, which appears earlier than that of lispro. The combination of miglitol and Mix50 seems effective for the control of PPG and lipid profile in T2D.

Comparative reactivity of remnant-like lipoprotein particles (RLP) and low-density lipoprotein (LDL) to LDL receptor and VLDL receptor: effect of a high-dose statin on VLDL receptor expression.

BACKGROUND: Comparison of the reactivity of remnant-like lipoprotein particles (RLP) and LDL particles to LDL receptor and VLDL receptor has not been investigated. METHODS: LDL receptor- or VLDL receptor-transfected ldlA-7, HepG2 and L6 cells were used. Human LDL and rabbit ß-VLDL were isolated by ultracentrifugation. Human RLP was isolated using an immunoaffinity mixed gel. The effect of statin on lipoprotein receptors was examined. RESULTS: Both LDL receptor and VLDL receptor recognized RLP. In LDL receptor transfectants, RLP, ß-VLDL and LDL all bound to LDL receptor. Cold RLP competed efficiently with DiI-ß-VLDL; however, cold LDL competed weakly. In VLDL receptor transfectants, RLP and ß-VLDL bound to VLDL receptor, but not LDL. RLP bound to VLDL receptor with higher affinity than ß-VLDL because of higher apolipoprotein E in RLP. LDL receptor expression was induced in HepG2 by the low concentration of statin while VLDL receptor expression was induced in L6 myoblasts at higher concentration. CONCLUSIONS: RLP are bound to hepatic LDL receptor more efficiently than LDL, which may explain the mechanism by which statins prevent cardiovascular risk by primarily reducing plasma RLP rather than by reducing LDL. Additionally, a high-dose of statins also may reduce plasma RLP through muscular VLDL receptor.

Glucose deprivation accelerates VLDL receptor-mediated TG-rich lipoprotein uptake by AMPK activation in skeletal muscle cells.

Glucose and fatty acids are major energy sources in skeletal muscle. Very low-density lipoprotein receptor (VLDL-R), which is highly expressed in heart, skeletal muscle and adipose tissue, plays a crucial role in metabolism of triglyceride (TG)-rich lipoproteins. To explore energy switching between glucose and fatty acids, we studied expression of VLDL-R and lipoprotein uptake in rat L6 myoblasts. l-Glucose or d-glucose deprivation in the medium noticeably induced the AMPK (AMP-activated protein kinase) activation and VLDL-R expression. Dose-dependent induction of VLDL-R expression was observed when d-glucose was less than 4.2mM. The same phenomenon was also observed in rat primary skeletal myoblasts and cultured vascular smooth muscle cells. The uptake of beta-VLDL but not LDL was accompanied by induction of VLDL-R expression. Our study suggests that the VLDL-R-mediated uptake of TG-rich lipoproteins might compensate for glucose shortfall through AMPK activation in skeletal muscle.