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.

Direct and indirect roles of GRWD1 in the inactivation of p53 in cancer.

Glutamate-rich WD40 repeat containing 1 (GRWD1), also known as WDR28, interacts with various proteins through its WD domain and is involved in transcription, translation, cell cycle progression, ubiquitin-mediated degradation and DNA replication and repair. Ribosomal protein L11 (RPL11), which directly interacts with MDM2, inhibits MDM2 ubiquitin ligase activity, thus promoting p53 stabilization. Binding of GRWD1 to RPL11 disrupts the interaction between RPL11 and MDM2 and promotes p53 ubiquitination by MDM2. In addition, a recent report by Fujiyama et al. found that GRWD1 also directly interacts with wild-type p53 and suppresses its transcriptional activity. They propose that GRWD1 is a novel tumor-promoting molecule that negatively regulates wild-type p53 via both indirect and direct mechanisms.

Ets family proteins regulate the EMT transcription factors Snail and ZEB in cancer cells.

The epithelial-mesenchymal transition (EMT) is a crucial morphological event that occurs during epithelial tumor progression. Snail and ZEB1/2 (ZEB1 and ZEB2), known as EMT transcription factors, are key regulators of this transition. ZEB1/2 are positively correlated with EMT phenotypes and the aggressiveness of cancers. On the contrary, Snail is also correlated with the aggressiveness of cancers, but is not correlated with the expression of EMT marker proteins. Snail is induced by transforming growth factor-ß (TGF-ß), a well-known inducer of EMT, in various cancer cells. Interestingly, Snail induction by TGF-ß is markedly enhanced by active Ras signals. Thus, cancer cells harboring an active Ras mutation exhibit a drastic induction of Snail by TGF-ß alone. Here, we found that members of the E26 transformation-specific (Ets) transcription factor family, Ets1 and Ets2, contribute to the upregulation of both Snail and ZEB1/2. Snail induction by TGF-ß and active Ras is dramatically inhibited using siRNAs against both Ets1 and Ets2 together, but not on their own; in addition, siRNAs against both Ets1 and Ets2 also downregulate the constitutive expression of Snail and ZEB1/2 in cancer cells. Examination of several alternatively spliced variants of Ets1 revealed that p54-Ets1, which includes exon VII, but not p42-Ets1, which excludes exon VII, regulates the expression of the EMT transcription factors, suggesting that Ets1 is a crucial molecule for regulating Snail and ZEB1/2, and thus cancer progression is mediated through post-translational modification of the exon VII domain.

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.

An association study of C9orf3, a novel component of the renin-angiotensin system, and hypertension in diabetes.

The renin-angiotensin system (RAS) is important in the onset and course of cardiovascular, kidney, and metabolic disorders. Previous reports showed that the RAS blockade protects organs and suppress the development of type 2 diabetes mellitus. A novel component of the RAS, namely, chromosome 9 open reading frame 3 (C9orf3), was recently identified, however, its effects are unclear. We evaluated whether the genetic variant of C9orf3 is associated with morbidity of hypertension among subjects with type 2 diabetes. We enrolled 382 subjects with type 2 diabetes, 222 of whom were diagnosed with hypertension. Human leukocyte genomic DNA was isolated and a genetic variant was analyzed for a C/T variant of C9orf3 (rs4385527) via PCR analysis. The relationship between the genotype and hypertension morbidity among subjects with diabetes was examined. The proportion of the respective C9orf3 genetic variants were as follows 247 CC, 119 CT, and 16 TT. The risk of hypertension was determined to be 1.58, with a 95% confidence interval of 1.11-2.27. Moreover, the p value was 0.012 for allelic comparison and for Armitage's trend test, with the C allele identified as the risk factor. Consequently, hypertension was markedly associated with type 2 diabetes in subjects with the C9orf3 variant, exhibiting a nearly 1.6-fold increased risk. The C variant of a new component of the RAS, C9orf3 (rs4385527) might have a considerable impact on the pathogenesis of hypertension in diabetes.

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.

A Genetic Variant in the Distal Enhancer Region of the Human Renin Gene Affects Renin Expression.

BACKGROUND: The high heritability of plasma renin activity was confirmed in recent investigations. A variation located near the strong enhancer of the human renin gene (REN), C-5312T, has been shown to have different transcription activity levels depending on its allele: the 5312T allele shows transcription levels that are 45% greater than those of the 5312C allele. The purpose of this study was to confirm the hypothesis that variations in the enhancer region of the REN gene are involved in regulating renal expression of renin. METHODS: Sixty-four subjects with biopsy-proven renal diseases were included in this study (male/female: 35/29, age 41.9 ± 20.9 years, SBP/DBP 123.1 ± 23.7/73.4 ± 14.8 mmHg, s-Cr 0.93 ± 0.63 mg/dl). A genetic variant of REN, C-5312T, was assayed by PCR-RFLP and the TaqMan method. Total RNAs from a small part of the renal cortex were reverse-transcribed and amplified for REN and GAPDH with a real-time PCR system. RESULTS: Logarithmically transformed expression values of the relative ratio of REN to GAPDH (10-3) were as follows (mean ± SE): CC (26 cases), 0.016 ± 0.005; CT (33 cases), 0.047 ± 0.021 (p = 0.41 vs. CC); TT (5 cases), 0.198 ± 0.194 (p = 0.011 vs. CC, p < 0.031 vs. CT). Thus, significant differences in REN expression were observed among the genetic variants. CONCLUSION: The results suggest that variants in the enhancer region of the human renin gene have an effect on the expression levels of renin in renal tissue; this observation is in good accordance with the results of the transcriptional assay.

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.

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.

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.

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.