Chii-Min Hwu

Abnormal cardiovascular reflex tests are predictors of mortality in Type 2 diabetes mellitus

SUMMARY

Waist circumference predicts metabolic cardiovascular risk in postmenopausal Chinese women.

Objective The purpose of the study is to compare the differences in metabolic cardiovascular risk factors among postmenopausal Chinese women with or without abdominal obesity. Design The study is a cross-sectional, population-based, comparative cohort study. Each participant received anthropometric measurements and a 75-g oral glucose tolerance test after an overnight fast. The homeostasis model assessment for insulin resistance and the insulin sensitivity index, ISI0,120, were used as measures of insulin resistance. A “metabolic cardiovascular risk score” was calculated from fasting insulin, glucose, lipids, and blood pressure. General linear models (GLM) were fit to examine the relation of waist circumference (WC) to insulin resistance and metabolic risk scores. Results According to the International Obesity Task Force obesity criteria for Asians, 57 women had abdominal obesity (WC ≥ 80 cm), and 58 had WCs less than 80 cm. The two groups were comparable in demographic variables and body mass index (BMI). The women with larger WCs were more insulin-resistant than their counterparts. The metabolic risk scores were significantly higher in women with abdominal obesity than in those without it. The results from the GLM showed that WC was an independent predictor of insulin resistance and metabolic risk scores after controlling for demographic variables (0.06- and 0.29-unit increases in homeostasis model assessment for insulin resistance and metabolic risk scores per 1 cm change in WC). Moreover, BMI neither correlated with metabolic risk scores nor affected the WC effects on insulin resistance and metabolic risk scores in the GLM. Conclusions Postmenopausal Chinese women with adbominal obesity may carry higher metabolic cardiovascular risk than those without it. It is WC, not BMI, that predicts metabolic cardiovascular risk factors in these women.

Increased concentrations of atrial and plasma atrial natriuretic peptide in castrated male rats

The effects of orchiectomy and testosterone replacement on the plasma concentration and the atrial stores of atrial natriuretic peptide (ANP) were studied in the rats. Male rats were orchiectomized (Orc) three weeks before replacement with testosterone propionate (TP, 20 mg/ml/kg body weight) or sesame oil for five days. Immunoreactive ANP (IR-ANP) in the extracted right atria and plasma of experimental rats was measured. Plasma ANP concentrations were 206 +/- 22, 927 +/- 151, and 264 +/- 61 pg/ml in normal control, Orc, and Orc + TP rats, respectively. ANP contents in right atria were higher in Orc (108 +/- 9 ng/mg tissue) and TP-treated Orc rats (123 +/- 9 ng/mg tissue) than in normal animals (32 +/- 7 ng/mg tissue). These results indicate an increased plasma concentration and atrial stores in the castrated male rats. Replacement of testosterone in the castrated male rats does not decrease the atrial ANP stores, but decreases the plasma ANP concentration.

Is Hyperuricemia Another Facet of the Metabolic Syndrome

Background: Hyperuricemia is commonly associated with obesity, glucose intolerance, hypertension, dyslipidemia, and atherosclerotic cardiovascular disease. The resemblance of the metabolic syndrome and hyperuricemia has led to the suggestion that hyperuricemia is a part of the metabolic syndrome. The purpose of this study is to examine the contribution of uric acid (UA) as an additional component of the metabolic syndrome in middle‐aged men. Methods: In total, 393 male participants, aged 45‐60 years, were recruited from a professional health evaluation program. Anthropometric measurements and blood pressure (BP) were taken after an overnight fast. Fasting blood samples were collected for the measurements of glucose, UA, and lipid profile. Logistic regression models were fitted to examine the relationship between UA and the diagnosis of metabolic syndrome. Factor analysis was performed to explore the relationship between UA and the components of the metabolic syndrome. Results: The diagnosis of the metabolic syndrome was significantly associated with waist circumference (WC), glucose, triglycerides (TG), high‐density lipoprotein cholesterol (HDL‐C), systolic BP, and liver enzyme levels, but not associated with UA levels. The sensitivity of hyperuricemia (serum UA = 7.0 mg/dL) for the diagnosis of the metabolic syndrome was 58.0% and the specificity was 55.3%. In factor analysis, UA aggregated with body mass index, WC, glucose, log TG, and HDL‐C as a metabolic factor. Systolic and diastolic BP were loaded on a second factor separately. The model loaded with UA explained a similar proportion of the total variance (56.9%), as did the model loaded without UA (62.5%). Conclusion: Our results suggest that the contribution of UA as an additional component of the syndrome seems to be insignificant. We propose that hyperuricemia might not be an important facet for the understanding of the underlying structure of the metabolic syndrome.

Prehypertension is associated with insulin resistance

BACKGROUND Prehypertension, a new category of blood pressure (BP) classification introduced by The Seven Report of the Joint National Commission (JNC-7) on High BP for individuals with systolic BP in the range of 120-139 mmHg or diastolic BP between 80 and 89 mmHg, is a strong predictor for the development of hypertension. Insulin resistance (IR) has been proposed to be a key feature of metabolic abnormalities of hypertension and may precede the elevation of BP. AIM The purpose of the study is to evaluate whether prehypertension is associated with IR. DESIGN This is a cross-sectional study. METHODS Anthropometric and BP measurements were performed in 83 prehypertensive subjects and 192 normotensives. All subjects received a 75-g oral glucose tolerance test (OGTT) for the measurements of IR. RESULTS The prehypertensive subjects were more obese and had higher levels of fasting triglycerides and 2-h insulin than the normotensives. The subjects with prehypertension were more insulin resistant than the counterparts, indicated by lower insulin sensitivity index, ISI(0,120), values. While there was no difference between the two groups in insulin response of OGTT after adjustments for confounders, the prehypertension group maintained significant between-group differences in glucose response even when the incremental insulin levels were added to covariates for adjustments. DISCUSSION Our data show that prehypertension is associated with IR. The subjects with prehypertension have clinical characteristics of the IR syndrome. It seems that the prehypertension group cannot handle oral glucose challenge as well as the normotension, probably a consequence of IR in prehypertension.

Sagittal abdominal diameter is associated with insulin sensitivity in Chinese hypertensive patients and their siblings

The purpose of the study is to observe the relation between anthropometric measurements, focusing on sagittal abdominal diameter (SAD), and insulin sensitivity indices in Chinese hypertensive patients and their siblings. In total, 907 participants, 537 hypertensive and 370 nonhypertensive, from 311 Taiwanese families were drawn from the Stanford Asia and Pacific Program for Hypertension and Insulin Resistance for the study. The participants received anthropometric measurements and 75-g oral glucose tolerance tests after an overnight fast. Fasting insulin, homeostasis model assessment for insulin resistance (HOMA-IR), and the insulin sensitivity index ISI0,120 were chosen as surrogate measures of insulin sensitivity. In addition to Pearson and partial correlations, we used generalized estimating equations (GEEs) to examine the association between anthropometric measurements and insulin sensitivity indices. A small deviance in the GEEs indicates the goodness of model fit, irrespective of the independence among variables. The hypertensive patients were older in age, wider in waist circumference (WC), larger in body mass index (BMI) and SAD, and more insulin resistant than the nonhypertensive counterparts. The logarithmic transformation of fasting insulin, HOMA-IR, and ISI0,120 significantly correlated with SAD, WC, and BMI before and after adjustments for age and sex. The deviances of SAD in the GEEs were similar to those of WC in all subjects, while BMI had smaller deviances than SAD and WC in the hypertensive patients. Our results suggest that the performance of SAD in predicting insulin sensitivity is comparable with WC in Chinese hypertensive patients and their siblings. BMI, however, seems to have better association with insulin sensitivity than SAD and WC in the patients with hypertension.

Lack of effect of simvastatin on insulin sensitivity in Type 2 diabetic patients with hypercholesterolaemia: results from a double-blind, randomized, placebo-controlled crossover study.

Aims To evaluate the effects of simvastatin on serum lipids and insulin sensitivity in Type 2 diabetic patients with hypercholesterolaemia.

Acipimox attenuates hypertriglyceridemia in dyslipidemic noninsulin dependent diabetes mellitus patients without perturbation of insulin sensitivity and glycemic control

Hyperlipidemia, hypertriglyceridemia in particular, is a common feature in patients with noninsulin dependent diabetes mellitus (NIDDM) and may associate with insulin insensitivity. Acipimox, being widely prescribed for treating hypertriglyceridemia, is also used in NIDDM patients for their dyslipidemia. In the present study, we evaluated the effect of acipimox in Chinese NIDDM patients with hypertriglyceridemia. A total of 16 patients enrolled in a double-blind, randomized, placebo-controlled and two-period crossover study. After an 8 week run-in period, patients were randomly assigned into two groups receiving either acipimox (250 mg, twice daily) or placebo treatment. A total of 12 weeks later, these two groups switched their treatment for an additional 12 weeks. Blood samples were collected at the end of the run-in period and then at 4-week intervals in the whole study for lipid profile. A modified insulin suppression test was performed at the ends of the run-in period, 12-week and 24-week treatment to assess changes in insulin sensitivity. Our results showed that acipimox significantly lowered serum total triglyceride while compared to those by placebo. However, no difference was observed in serum non-esterified fatty acid, low-density lipoprotein cholesterol, total cholesterol (TC), high density lipoprotein-cholesterol (HDL-C) and HDL-C/ TC ratio between the two groups. Furthermore, glycemic indices and insulin sensitivity were similar during the base-line, placebo or acipimox periods. Taken together, our data suggest that acipimox significantly lowered TG without perturbation of insulin sensitivity in hypertriglyceridemic NIDDM patients.

Glucose tolerance status and cognitive impairment in early middle-aged women

Aims  To examine the effect of glucose tolerance status on cognitive performance in early middle‐aged women.

Effects of long-term administration of octreotide on sodium retention and atrial natriuretic peptide in carbon tetrachloride-induced cirrhotic rats

BACKGROUND/AIMS To realize the roles of peripheral vasodilatation and atrial natriuretic peptide in the formation of cirrhotic ascites, the effects of long-term administration of octreotide on carbon tetrachloride-induced cirrhotic rats were evaluated. METHODS Urine sodium excretion, hemodynamics, plasma atrial natriuretic peptide levels, renin activities and aldosterone concentrations were compared between cirrhotic and control rats (protocol 1); and between octreotide- (65 micrograms/kg, twice daily for 10 days, subcutaneously) and placebo-treated (5% dextrose) cirrhotic rats (protocol 2). In an in vitro experiment, right atrial tissue of cirrhotic rats was incubated with different concentrations of octreotide to evaluate the release of atrial natriuretic peptide (protocol 3). RESULTS Cirrhotic rats had significantly lower urine sodium excretion and systemic vascular resistance, and significantly higher plasma atrial natriuretic peptide levels, renin activities and aldosterone concentrations than control rats. Compared with placebo-treated cirrhotic rats, octreotide caused increased urine sodium excretion (-10 +/- 4% vs. 13 +/- 8% from baseline values, p < 0.05) and systemic vascular resistance (2.6 +/- 0.1 vs. 3.3 +/- 0.3 mmHg.min.100 g.ml-1, p < 0.05); and decreased plasma atrial natriuretic peptide levels (166.7 +/- 24.8 vs. 234.0 +/- 19.2 pg/ ml, p < 0.05), renin activities (2.45 +/- 0.49 vs. 4.36 +/- 0.53 ng.ml-1.h-1, p < 0.01) and aldosterone concentrations (290.2 +/- 40.0 vs. 483.3 +/- 82.6 pg/ml, p < 0.05). In the in vitro experiment, right atrial release of atrial natriuretic peptide of cirrhotic rats was not significantly changed when incubated with different concentrations of octreotide. CONCLUSIONS Octreotide ameliorates renal sodium retention and suppresses plasma levels of atrial natriuretic peptide of ascitic cirrhotic rats with a novel mechanism via, at least partly, the modification of peripheral vascular resistance.