Shoichi Tomono

Association analyses of the polymorphisms of angiotensin-converting enzyme and angiotensinogen genes with diabetic nephropathy in Japanese non-insulin-dependent diabetics

To investigate predictive genetic markers for diabetic nephropathy, we studied the genetic polymorphisms of angiotensin-converting enzyme (ACE) and angiotensinogen (AGN) in Japanese subjects with non-insulin-dependent diabetes mellitus (NIDDM) with and without nephropathy. Genotype distributions were studied in 132 unrelated NIDDM patients of three groups with normoalbuminuria ([Normo] n = 53), microalbuminuria ([Micro] n = 54), and macroalbuminuria ([Macro] n = 25). The ACE insertion/deletion (I/D) polymorphism of intron 16 was identified by polymerase chain reaction, and the AGN M235T polymorphism was identified by restriction fragment length polymorphism analysis. There were no significant associations between AGN 235 allele or genotype and diabetic nephropathy. The D allele of ACE was significantly more frequent in the Micro (P = .003) and Macro (P = .009) group than in the Normo group. Overall frequencies of the ACE genotype did not differ significantly between the Micro and Macro groups. There were significant relationships between I/D polymorphism and plasma ACE activity; the DD genotype had the highest activity. A multiple logistic regression analysis revealed that the D allele is a strong and independent risk factor for abnormal albuminuria in NIDDM patients. These results suggested that ACE I/D polymorphism, but not AGN M235T polymorphism, is a possible genetic risk factor for diabetic nephropathy in Japanese NIDDM patients.

Genistein augments cyclic adenosine 3'5'-monophosphate(cAMP) accumulation and insulin release in MIN6 cells.

Effects of genistein on insulin release were studied using MIN6 cells, a glucose-sensitive insulinoma cell line. At the non-stimulatory concentrations of glucose, genistein did not affect insulin release, however, at the stimulatory concentrations of glucose, genistein significantly increased insulin release in a dose-dependent manner up to 20 micrograms/ml. The content of cAMP in MIN6 cells was also elevated significantly by genistein and the dose-response relationship between the genistein and cAMP accumulation was consistent with the relationship between the genistein and insulin release. These effects were inhibited by calcium antagonists or by the omission of extracellular calcium. Isobutylmethylxanthine (IBMX;0.1mM) increased both cAMP accumulation and insulin release in MIN6 cells and there were no additive effects by the addition of genistein. The accumulation of cAMP might have, at least in part, resulted from phosphodiesterase inhibition by genistein. These results suggest that genistein augments glucose-induced insulin release by the contribution of cAMP accumulation and calcium modulation which depends on extracellular calcium.

The relationship between early diabetic nephropathy and control of plasma glucose in non-insulin-dependent diabetes mellitus: The effect of glycemic control on the development and progression of diabetic nephropathy in an 8-year follow-up study

To clarify the relationship between early diabetic nephropathy and the glycemic control in non-insulin-dependent diabetes mellitus (NIDDM) without hypertension, excretion of urinary albumin was studied retrospectively for 8 years. The patients with early diabetic nephropathy were divided into two groups according to the initial urinary albumin index (UAI: mg/g.creatinine), namely, a normoalbuminuric (less than 15 mg/g.creatinine) and a microalbuminuric group (15 < or = UAI < 200 mg/g.creatinine). Comparisons of changes in UAI were made between good (HbA1 < 9.0% and fasting plasma glucose (FPG) < 140 mg/100 mL throughout the observation period) and poor glycemic control groups after 4 and 8 years. In the patients with normoalbuminuria at the initial determination, five of 11 patients (45.5%) with good glycemic control and 14 of 22 patients (63.6%) with poor glycemic control became microalbuminuric after 8 years, respectively (p < 0.05). In the microalbuminuric patients, five of ten patients (50%) with poor glycemic control became macroalbuminuric (UAI > or = 200 mg/g.creatinine), although only one case worsened of five patients with good glycemic control (p < 0.05). In conclusion, the development or progression of early diabetic nephropathy in NIDDM was significantly inhibited by good glycemic control (FPG < 140 mg/100 mL and HbA1 < 9.0%), independent of hypertension, and probably irrespective of the mode of therapeutic intervention.

Hormone Replacement Therapy Decreases Insulin Resistance and Lipid Metabolism in Japanese Postmenopausal Women with Impaired and Normal Glucose Tolerance

Objects: To investigate the effect of combined estrogen and progesterone therapy on insulin resistance (IR) and carbohydrate and lipid metabolism in postmenopausal women (PMW) with impaired (IGT) and normal glucose tolerance (NGT). Methods: Sixteen Japanese PMW with IGT and 33 with NGT received daily oral hormone replacement therapy (HRT; 0.625 mg of conjugated equine estrogen plus 2.5 mg of medroxyprogesterone acetate) for 12 months. As controls, 13 Japanese PMW with IGT and 31 with NGT were enrolled and not treated by HRT. Fasting plasma glucose (FPG), fasting immunoreactive insulin (IRI), and IR were measured in each subject at study initiation and 12 months later. We used homeostasis model assessment (HOMA) to determine IR. Results: FPG and HOMA IR were decreased in both HRT groups, and fasting IRI was reduced in the HRT-NGT group. In controls, FPG, fasting IRI, and HOMA IR were unaltered. Total and low-density lipoprotein cholesterol were decreased and high-density lipoprotein cholesterol was increased in both HRT groups, but triglyceride was unchanged. In controls, lipid metabolism was unaltered. Conclusion: HRT decreased IR and improved carbohydrate and lipid metabolism in Japanese PMW with IGT and NGT. These beneficial effects argue for the use of HRT in PMW with IGT as well as NGT.

Clinical significance of neutrophil apoptosis in peripheral blood of patients with type 2 diabetes mellitus.

UNLABELLED Although neutrophils are essential components of the natural immune system, they have also been implicated in the pathogenesis of tissue injuries. We assessed the clinical significance of neutrophil apoptosis in the peripheral blood of patients with type 2 diabetes mellitus (T2DM). PATIENTS AND METHODS The study included 52 patients with T2DM (30 men, 22 women). Control subjects were 16 healthy volunteers without diabetes (7 men, 9 women). Neutrophil apoptosis levels were measured active caspase-3 positive rate by flow cytometry. RESULTS The mean rate of neutrophil apoptosis in patients with T2DM was 15.0% (95% confidence interval [CI]: 9.5% approximately 20.5%), while that in the control group was 5.8% (95% CI: 1.6% approximately 10.0%). There were significant negative correlations between neutrophil apoptosis rate and hemoglobin (Hb) A1c levels (r = -0.352, P < .01). The mean rate of neutrophil apoptosis in the patient group with the 3 major complications (diabetic retinopathy, nephropathy, and neuropathy) was 11.1% (95% CI: 5.5%-16.7%, n = 36) and that of another group without complications was 23.8% (95% CI: 11.4%-36.2%, n = 16). There was a significant difference between these 2 groups (P < .05). CONCLUSIONS The neutrophil apoptosis rate in patients with T2DM was significantly correlated with HbA1C levels. The mean rate of neutrophil apoptosis in the patient group with 3 major diabetic complications remained lower than that in another patient group without complications. The inhibition of neutrophil apoptosis by chronic hyperglycemia is thought to promote tissue injury and to enhance the risk of microangiopathy.

Clinical implications of serum levels of basement membrane components in diabetic patients with and without albuminuria.

Serum levels of type IV collagen (7S-IV) and laminin P1 in 185 non-insulin-dependent diabetes mellitus patients were significantly higher than those in normal subjects. Furthermore, they were significantly elevated in relation to the excretion of urinary albumin, showing their increases even at the stage of microalbuminuria, although they were not correlated with HbA1c or age in diabetic patients. Thus, the determination of serum levels of basement membrane components, 7S-IV and laminin, could be beneficial as the early indices of diabetic microangiopathy, including diabetic nephropathy.

Oral administration of branched chain amino acids improves virus-induced glucose intolerance in mice.

We investigated the therapeutic effect of branched chain amino acids (BCAA) on mice with glucose intolerance induced by encephalomyocarditis virus (EMCV). Male DBA/2 mice were divided into three groups: treated with BCAA, (such as valine, leucine, and isoleucine), untreated, and control. BCAA-treated and -untreated groups were inoculated intraperitoneally with the NDK25 variant of EMCV at 200 plaque-forming units per mouse. The BCAA-treated group was administered orally 0.9 g/kg/day of each BCAA from the day after viral inoculation. The control group neither received virus inoculation nor was treated with BCAA. One week after inoculation, oral glucose tolerance tests (OGTT) were performed. After the glucose loading at 1.5 g/kg of body weight, blood glucose levels in the untreated group were 92.0+/-10.0 mg/dl at baseline, 224.6+/-10.9 mg/dl at 30 min, and 169.4+/-21.4 mg/dl at 60 min, which were significantly (P<0.05) higher than those in the control group (62. 7+/-3.6 mg/dl, 167.2+/-16.4, and 83.8+/-6.0 mg/dl, respectively). Blood glucose levels in the BCAA-treated group were 54.5+/-3.7 mg/dl at baseline, 145.2+/-8.7 mg/dl at 30 min, and 128.7+/-18.3 mg/dl at 60 min after the glucose loading, which were not significantly higher than those in the control group. Immunoreactive insulin levels at 30 min after the glucose loading were lower in the untreated group than in the control group at 1 week after virus inoculation. Histological investigations showed that the grade of insulitis in the pancreas of mice of the BCAA-treated group was lower than that of the mice of the untreated group. These results suggest that oral administration of BCAA is able to improve glucose intolerance induced by EMCV.

The role of insulin in coronary atherosclerosis

In 197 patients with coronary artery disease (CAD) who underwent coronary angiography, 75 g oral glucose tolerance test (OGTT) was performed, measuring plasma glucose(PG) and plasma insulin (IRI) at 4 time points (0, 30, 60 and 120 min). Subjects were separated into two groups by their insulinogenic index (I.I. = delta IRI/delta PG from 0 up to 30 min), 99 cases with good insulin response (I.I. > or = 0.4) and 98 cases with poor insulin response (I.I. < 0.4). Only two subjects were diabetic in good insulin response, while 37 were diabetic in poor insulin response. The severity of coronary atherosclerosis was expressed as a coronary index (CI), calculated according to Balcons method. Fasting PG and the sum of PG were significantly higher in the latter group, while the sum of IRI was significantly lower. CI was not significantly different, however. In the group with good insulin response, the severity of CAD was significantly correlated to fasting IRI (n = 99, r = -0.387, P < 0.02), but, there was no such relationship in the other group. We conclude that hyperinsulinemia might be a risk factor for ischemic heart disease, but in diabetics it is difficult to link the relationship between fasting IRI and CI.

Calcification of the Carotid Arteries, a Clinical Sign of Severe Generalized Atherosclerosis

X線写真上の頚動脈石灰化像に関し, 40歳以上983例 (男619例, 女364例) について検討した. 頚動脈石灰化は40歳代では男90例, 女46例中で1例も認められなかった. 50歳代では男168例中2例 (1.2%),女128例中3例 (2.3%), 60歳代では男233例中45例 (19.3%), 女130例中5例 (3.8%), 70歳代では男128例中35例 (27.3%), 女60例中10例 (16.7%) に認められ, 60歳以降急速に出現頻度が高まった. 60歳代では男に有意に高頻度であり (p<0.001), 70歳代でもその傾向は認められた. 頚動脈石灰化例では高血圧, 耐糖能低下, 脳卒中の合併率も高く, また大動脈弓部あるいは腹部大動脈石灰化の合併も高率であった. これらより, 頚動脈石灰化は高度な全身性動脈硬化の存在を示唆する重要な所見と考えられた.

Alamandine reduces leptin expression through the c-Src/p38 MAP kinase pathway in adipose tissue

Objective Obesity is associated with an increased risk of diabetes mellitus, hypertension, and renal dysfunction. Angiotensin 1–7 and alamandine are heptameric renin angiotensin system peptide hormones. Further, alamandine levels increase with renal dysfunction. In the cardiovascular system, angiotensin 1–7 and alamandine produce similar improvements and counterbalance angiotensin II in regulating vascular function. We aimed to determine whether the effect of alamandine on leptin expression and secretion in adipocytes was similar to that of angiotensin 1–7. Approach and results We studied isolated peri-renal visceral adipose tissue and peri-renal isolated visceral adipocytes from male Wistar rats. Angiotensin II from 0.01 to 10nM had no effect on leptin expression. Angiotensin 1–7 (1 nM) increased leptin secretion and expression, whereas alamandine (1 nM) decreased leptin secretion and expression in adipose tissue and isolated adipocytes and reduced blood leptin levels in vivo. These effects were mediated by Gq, c-Src, p38 mitogen-activated protein, and IκB activation. Additionally, alamandine induced nitric oxide expression via inducible nitric oxidase synthase and plasminogen activator inhibitor 1 expression in adipose tissue and isolated adipocytes. Conclusions Angiotensin 1–7 and alamandine produced opposing effects on leptin expression and secretion in adipose tissue. This result suggests that the action of Mas (angiotensin 1–7 receptor) and Mas-related G-protein coupled receptor D in adipocytes exhibited opposing actions similar to angiotensin II type 1 and type 2 receptors.