Ryotaro Bouchi

Arterial Stiffness Is Associated With Incident Albuminuria and Decreased Glomerular Filtration Rate in Type 2 Diabetic Patients

OBJECTIVE To investigate the association between aortic stiffness and incident albuminuria and the decline in estimated glomerular filtration rate (eGFR) in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS We investigated 461 Japanese type 2 diabetic patients, comprising 199 women and 262 men, with a mean age of 59 ± 11 years. Patients were divided into two groups according to the median value of carotid-femoral pulse wave velocity (cf-PWV), which was used to evaluate aortic stiffness. The end point was defined as the transition from normo- to microalbuminuria or micro- to macroalbuminuria. The Cox proportional hazard model was used to calculate the hazard ratio (HR) and 95% CI. The correlation between cf-PWV and rate of change in eGFR was also determined by linear regression analysis. RESULTS The baseline mean (± SD) cf-PWV was 9.6 ± 2.4 m/s. During a median follow-up period of 5.9 years (range 0.3–8.6), progression of albuminuria was observed in 85 patients. The 5-year cumulative incidence of the end point in patients with cf-PWV below and above the median was 8.5 and 19.4%, respectively (P = 0.002, log-rank test). cf-PWV was significantly associated with incident albuminuria (HR 1.23, 95% CI 1.13–1.33, P < 0.001) by multivariate Cox regression analysis. A significant association between cf-PWV and annual change in eGFR was also suggested by multiple linear regression analysis (standardized estimate −0.095, P = 0.031). CONCLUSIONS Aortic stiffness is associated with incident albuminuria and the rate of decline in glomerular filtration rate in type 2 diabetic patients.

FOXO1 inhibition yields functional insulin-producing cells in human gut organoid cultures

Generation of surrogate sources of insulin-producing β-cells remains a goal of diabetes therapy. While most efforts have been directed at differentiating embryonic or induced pluripotent stem (iPS) cells into β-like-cells through endodermal progenitors, we have shown that gut endocrine progenitor cells of mice can be differentiated into glucose-responsive, insulin-producing cells by ablation of transcription factor Foxo1. Here we show that FOXO1 is present in human gut endocrine progenitor and serotonin-producing cells. Using gut organoids derived from human iPS cells, we show that FOXO1 inhibition using a dominant-negative mutant or lentivirus-encoded shRNA promotes generation of insulin-positive cells that express all markers of mature pancreatic β-cells, release C-peptide in response to secretagogues, and survive in vivo following transplantation into mice. The findings raise the possibility of using gut-targeted FOXO1 inhibition or gut organoids as a source of insulin-producing cells to treat human diabetes.

Integration of transcriptome and methylome analysis of aldosterone-producing adenomas

OBJECTIVE The pathophysiology of aldosterone-producing adenomas (APA) has been investigated intensively through genetic and genomic approaches. However, the role of epigenetics in APA is not fully understood. In the present study, we explored the relationship between gene expression and DNA methylation status in APA. METHODS We conducted an integrated analysis of transcriptome and methylome data of paired APA-adjacent adrenal gland (AAG) samples from the same patient. The adrenal specimens were obtained from seven Japanese patients with APA who underwent adrenalectomy. Gene expression and genome-wide CpG methylation profiles were obtained from RNA and DNA samples that were extracted from those seven paired tissues. RESULTS Methylome analysis showed global CpG hypomethylation in APA relative to AAG. The integration of gene expression and methylation status showed that 34 genes were up-regulated with CpG hypomethylation in APA. Of these, three genes (CYP11B2, MC2R, and HPX) may be related to aldosterone production, and five genes (PRRX1, RAB38, FAP, GCNT2, and ASB4) are potentially involved in tumorigenesis. CONCLUSION The present study is the first methylome analysis to compare APA with AAG in the same patients. Our integrated analysis of transcriptome and methylome revealed DNA hypomethylation in APA and identified several up-regulated genes with DNA hypomethylation that may be involved in aldosterone production and tumorigenesis.

Fluctuations in HbA1c are associated with a higher incidence of cardiovascular disease in Japanese patients with type 2 diabetes

Aims/Introduction:  To reveal whether visit‐to‐visit variability in HbA1c is associated with higher risk of cardiovascular disease (CVD) in patients with type 2 diabetes.

Gender differences in the association between HDL cholesterol and the progression of diabetic kidney disease in type 2 diabetic patients

BACKGROUND The impact of serum lipid abnormalities on the progression of diabetic kidney disease (DKD) remains conflicting. Furthermore, gender differences in the association between dyslipidaemia and outcome of DKD are largely unknown. We therefore conducted this single-centre observational cohort study to clarify gender differences in the association between serum lipid profiles and the progression of DKD. METHODS Seven hundred and twenty-three Japanese type 2 diabetes mellitus (T2DM) patients with normoalbuminuria or microalbuminuria, 280 women and 443 men, with a mean (± SD) age of 63 ± 11 years were studied. The endpoint was the progression to a more advanced stage of albuminuria. For statistical analyses, Cox proportional hazard model analyses were conducted. RESULTS During the mean follow-up period of 4.3 years, 62 of 477 patients with normoalbuminuria and 69 of 246 patients with microalbuminuria reached the endpoint. A significant interaction between high-density lipoprotein (HDL) cholesterol and gender was detected (P(interaction) = 0.04); therefore, separate analyses were conducted for men and women. Overall, in men, the univariate Cox proportional hazard model revealed that higher triglycerides and lower HDL cholesterol levels were significantly associated with higher risk of reaching the endpoint. In the multivariate Cox proportional hazard model, only HDL cholesterol levels remained as an independent predictor of the endpoint (hazard ratio 0.391, P = 0.01). In women, no serum lipid parameters were associated with the endpoint. CONCLUSIONS Lower HDL cholesterol levels seem to be associated with the progression of DKD in men but not in women.

Impact of increased visceral adiposity with normal weight on the progression of arterial stiffness in Japanese patients with type 2 diabetes

Objective Normal-weight abdominal obesity has been reported to be associated with poor mortality. We aimed to investigate the impact of increased visceral adiposity with normal weight (OB(−)VA(+)) on the progression of arterial stiffness in patients with type 2 diabetes. Methods This was a cross-sectional study of 414 patients with type 2 diabetes (mean age 64±12 years; 40.3% female). Visceral fat area (VFA, cm2) was measured by a dual bioelectrical impedance analyzer. Arterial stiffness was assessed by brachial-ankle pulse wave velocity (baPWV, cm/s). Patients were divided into four groups by VFA and body mass index (BMI, kg/m2) as the following: BMI<25 kg/m2 and VFA<100 cm2 (obesity (OB)(−)visceral adiposity (VA)(−)), BMI≥25 kg/m2 and VFA<100 cm2 (OB(+)VA(−)), BMI<25 kg/m2 and VFA≥100 cm2 (OB(−)VA(+)), and BMI≥25 kg/m2 and VFA≥100 cm2 (OB(+)VA(+)). Multivariate linear regression analysis was done to determine the impact of OB(−)VA(+) on arterial stiffness. Results Among the patients, 7.2% were OB(−)VA(+) with higher baPWV levels (1956±444 cm/s) than those with OB(+)VA(−) (1671±416 cm/s, p=0.014), those with OB(+)VA(+) (1744±317 cm/s, p=0.048), and those with OB(−)VA(−) (1620±397 cm/s, p=0.024). In multivariate linear regression analysis, OB(−)VA(+) remained independently associated with baPWV (standardized β 0.184, p=0.001). Conclusions This study provides evidence for the burden of arterial stiffness in OB(−)VA(+) patients with type 2 diabetes; therefore, evaluation of visceral adiposity is of clinical relevance for the better management of non-obese individuals as well as obese populations.

Non-linear association between ankle-brachial pressure index and prevalence of silent cerebral infarction in Japanese patients with type 2 diabetes

OBJECTIVE Patients with peripheral artery disease (PAD), defined as having low ankle-brachial pressure index (ABI), have increased risk for incident stroke compared with those without PAD. We aimed to reveal whether ABI abnormality, especially high ABI is associated with prevalent silent cerebral infarction (SCI) in type 2 diabetic patients. METHODS We studied 538 Japanese type 2 diabetic patients, 227 women and 311 men, with a mean [±SD] age of 64±11 years. All patients underwent cranial magnetic resonance imaging (MRI). Values of ABI were classified as low (<0.9), normal (0.9≤ and <1.3), and high (1.3≤). Logistic regression model was used to calculate odds ratio and 95% confidence interval (95% CI) for prevalent SCI. RESULTS The mean ABI among the overall 538 patients was 1.09±0.16. Low and high ABI values were found in 52 (9.7%) and 33 (6.1%) patients, respectively. SCI was detected in 297 (55.2%) patients. The prevalence in patients with low, normal, and high ABI values were 88.5%, 49.7%, and 78.8 (p<0.001), respectively. In the multivariate logistic regression analysis, both patients with high and low ABI were significantly increased risk of prevalent SCI (odds ratio 4.53, 95% CI 1.67-12.34, p=0.003 and odds ratio 3.50, 95% CI 1.50-10.29, p=0.005), independently of other traditional cardiovascular risk factors, than those with normal ABI. CONCLUSIONS Both high and low ABI may be strongly associated with prevalent SCI in Japanese patients with type 2 diabetes.

Reduction of visceral fat by liraglutide is associated with ameliorations of hepatic steatosis, albuminuria, and micro-inflammation in type 2 diabetic patients with insulin treatment: a randomized control trial

Liraglutide, an analogue of human glucagon-like peptide 1, reduces cardiovascular events in patients with type 2 diabetes; however, it has still been unknown by which mechanisms liraglutide could reduce cardiovascular events. Type 2 diabetic patients with insulin treatment were enrolled in this randomized, open-label, comparative study. Participants were randomly assigned to liraglutide plus insulin (liraglutide group) and insulin treatment (control group) at 1:1 allocation. Primary endpoint was the change in viscera fat are (VFA, cm2) at 24 weeks. Liver attenuation index (LAI) measured by abdominal computed tomography, urinary albumin-to-creatinine ratio (ACR, mg/g), and C-reactive protein (CRP) levels, skeletal muscle index (SMI), and quality of life (QOL) related to diabetes treatment were also determined. Seventeen patients (8; liraglutide group, 9; control group, mean age 59 ± 13 years; 53% female) completed this study. Liraglutide treatment significantly reduced VFA at 24 weeks; whereas, SFA was unchanged. ACR, LAI, and CRP levels were significantly reduced by liraglutide at 24 weeks and there was no difference in SMI between the two groups. Changes in VFA from baseline to 24 weeks were significantly associated with those in LAI, albuminuria, and HbA1c. Liraglutide treatment significantly improved QOL scores associated with anxiety and dissatisfaction with treatment and satisfaction with treatment. No severe adverse events were observed in both groups. Our data suggest that liraglutide could reduce visceral adiposity in parallel with attenuation of hepatic fat accumulation, albuminuria and micro-inflammation and improve QOL related to diabetes care in insulin-treated patients with type 2 diabetes.

Indirect measure of visceral adiposity ‘A Body Shape Index’ (ABSI) is associated with arterial stiffness in patients with type 2 diabetes

Objective Among indirect measures of visceral adiposity, A Body Shape Index (ABSI), which is defined as waist circumference (WC)/(body mass index (BMI)2/3×height1/2), is unique in that ABSI is positively correlated with visceral adiposity and is supposed to be independent of BMI. ABSI has been also shown to be linearly and positively associated with visceral fat mass and all-cause and cardiovascular disease (CVD) in the general population. It is, however, uncertain whether ABSI could be associated with arterial stiffness in patients with diabetes. Methods This is a cross-sectional study of 607 patients with type 2 diabetes (mean age 64±12 years; 40.0% female). Visceral fat area (VFA, cm2) and subcutaneous fat area (SFA, cm2) were assessed with a dual-impedance analyzer. In order to estimate the risk for CVD, brachial-ankle pulse wave velocity (baPWV, cm) was used for the assessment of arterial stiffness. Results ABSI was significantly and positively correlated with VFA (r=0.138, p=0.001) and negatively associated with BMI (r=−0.085, p=0.037). The correlation of z-score for ABSI with VFA remained significant (r=0.170, p<0.001) but not with BMI (r=0.009, p=0.820). ABSI (standardized β 0.095, p=0.043) but not WC (standardized β −0.060, p=0.200) was significantly and positively correlated with baPWV in the multivariate model including BMI as a covariate. Conclusions ABSI appears to reflect visceral adiposity independently of BMI and to be a substantial marker of arterial stiffening in patients with type 2 diabetes.

Silent cerebral infarction is associated with the development and progression of nephropathy in patients with type 2 diabetes

Chronic kidney disease (CKD) is an important risk factor for cardiovascular disease in patients with diabetes. The relationship between renal manifestations of CKD (albuminuria and decreased glomerular filtration rate) and silent cerebral infarction (SCI) has attracted attention; however, most studies examined the effects of components of CKD on prevalence of SCI. We sought to assess the relationship between SCI and the development and progression of nephropathy in type 2 diabetic patients. We studied 366 type 2 diabetic patients with normoalbuminuria (urinary albumin-to-creatinine ratio [ACR] <30 mg g–1, N=246) or microalbuminuria (ACR=30–299 mg g–1, N=120). SCI was defined by cranial MRI. The primary end point was progression from normo- to microalbuminuria or from micro- to macroalbuminuria. The cumulative incidence of the primary end point was estimated using the Kaplan–Meier method. Risk estimates for reaching the end point were calculated using Cox proportional hazard model analyses. During a median follow-up period of 3.9 years, 23 normoalbuminuric and 24 microalbuminuric patients reached the primary end point. Patients with SCI (N=171) had a greater incidence of reaching the end point than those without SCI (N=195, P=0.020 by the log-rank test), with a hazard ratio of 2.02 (95% confidence interval=1.09–3.72, P=0.025) in the multivariate Cox regression model. Although the common pathogenesis of SCI and albuminuria in diabetic patients is still unclear, SCI may be a predictor of progression of nephropathy in type 2 diabetic patients.