Remnant-like particle cholesterol, triglycerides, and insulin resistance in nonobese Japanese type 2 diabetic patients

Remnant Cholesterol is More Strongly Associated with Arterial Stiffness than Traditional Lipids and Lipid Ratios in the General Chinese Population

AIM

Studies on the relationship between remnant cholesterol (RC) and arterial stiffness (AS) are limited. This study aims to investigate the relationship between RC and AS and to explore RC, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), non-HDL-C, LDL-C/HDL-C, TG/HDL-C, lipoprotein combine index (LCI), and TC/HDL-C, which are lipid parameters most strongly associated with AS.

METHODS

A total of 4653 participants from the REACTION (Risk Evaluation of Cancers in Chinese Diabetic Individuals) study were recruited. AS was defined as a brachial-ankle pulse wave velocity of ≥ 1400 cm/s. Multiple logistic regression analyses were performed to detect its association with lipid parameters (RC, TG, TC, HDL-C, LDL-C, non-HDL-C, LDL-C/HDL-C, TG/HDL-C, LCI, and TC/HDL-C).

RESULTS

Logistic regression analysis showed that compared with other traditional or non-traditional lipid parameters, the association between RC and AS was the strongest (odds ratio (OR) 1.59, 95% confidence interval (CI) 1.30-1.95, P＜0.001). In the stratified analysis, RC was significantly associated with AS in both sexes and at any age, as well as blood glucose, blood pressure, and body mass index levels. Besides, RC and AS were still significantly associated when TG＜1.7 mmol/L (OR:1.58, 95% CI: 1.02-2.45, P=0.04), LDL-C ＜3.4 mmol/L (OR:1.32, 95% CI: 1.01-1.73, P=0.041), HDL-C ≥ 1.0 mmol/L (OR:1.67, 95% CI: 1.34-2.08, P＜0.001), or non-HDL-C＜4.1 mmol/L (OR: 1.42, 95% CI: 1.10-1.82, P=0.007) are controlled within the appropriate range.

CONCLUSION

In conclusion, compared with traditional lipids and lipid ratios, RC is more strongly associated with AS. The association between RC and AS remains significant even when TG, LDL-C, HDL-C, or non-HDL-C levels are controlled within the appropriate range.

Association of remnant cholesterol and newly diagnosed early-onset type 2 diabetes mellitus in Chinese population: A retrospective cross-sectional study

BACKGROUND

With the increasing incidence of diabetes worldwide, patients diagnosed with diabetes has been getting younger. Previous studies have shown that high remnant cholesterol (RC) level leads to an increased risk of cardiovascular disease events. However, the relationship between RC levels and newly diagnosed early-onset type 2 diabetes mellitus (T2DM) is unknown. This study aimed to explore the association between RC and newly diagnosed early-onset T2DM.

METHODS

A total of 606 patients newly diagnosed with early-onset T2DM and 619 gender-matched subjects with normal blood glucose levels were retrospectively enrolled in this study. All T2DM patients showed onset age of 18-40 years. Binary logistic regression analysis was performed to analyze independent risk factors and receiver operating characteristic (ROC) analysis was used to explore the predictive value of RC and other unconventional lipids. Moreover, the correlation between RC and insulin resistance in patients with newly diagnosed early-onset T2DM was also examined with binary logistic regression analysis and Spearman correlation analysis.

RESULTS

Increased RC level was an independent risk factor for early-onset T2DM (p < .05). The area under the curve on ROC analysis of RC was 0.805, 95% confidence interval (CI) was 0.781 ~ 0.826, sensitivity was 82.18% and specificity was 66.24%, which showed higher predictive value than those of triglyceride/high-density lipoprotein cholesterol (TG/HDL-C) ratio and total cholesterol (TC)/HDL-C ratio. Cutoff value of RC was 0.32 mmol/L. Level of RC in early-onset T2DM patients with moderate or severe insulin resistance was significantly higher than that in patients with mild insulin resistance (p < .0001). No difference in RC levels was found between patients with moderate and severe insulin resistance (p > .05). RC was still correlated with insulin resistance after adjusting the conventional lipid parameters (TG, TC, HDL-C, and low-density lipoprotein cholesterol) using partial correlation analysis.

CONCLUSION

RC level was higher in patients with early-onset T2DM and was correlated to the degree of insulin resistance as well. Patients aged 18-40 years with RC >0.32 mmol/L showed an increased risk of developing T2DM.

Counterintuitive relationship between the triglyceride glucose index and diabetic foot in diabetes patients: A cross-sectional study

BACKGROUND

Research has shown that insulin resistance (IR) is a known risk factor for diabetic foot (DF), and the triglyceride-glucose (TyG) index is a reliable and simple indicator of IR. However, less is known about the relationship between the TyG and the risk of DF. Here, we investigated the association between the TyG index and the prevalence of DF.

METHODS

The eligible records from the Departments of Endocrinology of Shandong Provincial Hospital Affiliated to Shandong First Medical University were screened (from December 1, 2012, to December 31, 2021), and a total of 8866 patients were enrolled. The TyG index was calculated as ln[(fasting triglycerides (mg/dL)×fasting glucose (mg/dL)/2)]. The continuous variables between the DF and the non-DF groups were compared by Student's t test or the Mann-Whitney U test, and categorical variables were compared by the chi-square test. Receiver operating characteristic curve (ROC) analysis was carried out to estimate the predictive value of the TyG index for DF. Logistic regression models were used to evaluate the associations between the quartiles of the TyG index and the risk of DF. Subgroup and sensitivity analyses were conducted.

RESULTS

The TyG index was significantly lower in the DF group than in the no-DF group. The logistic regression revealed that an increased TyG index was associated with a lower risk of DF after adjusting for potential confounders. In addition, an ROC analysis indicated the discriminatory ability of the TyG index in DF presence with an area under the curve (AUC) of 0.661 (95% CI 0.642-0.680, P < 0.001). Subgroup and sensitivity analysis also supported these robust results.

CONCLUSIONS

The TyG index was inversely and dose-dependently associated with the risk of DF in diabetes patients, indicating that elevated TyG index was a protective factor for DF. Future studies are therefore warranted to confirm our finding and to explore the detailed pathological mechanism involved in this process.

Serum metabolomics probes the molecular mechanism of action of acupuncture on metabolic pathways related to glucose metabolism in patients with polycystic ovary syndrome-related obesity

Polycystic ovary syndrome (PCOS) is a common endocrine syndrome, and obesity is the most common clinical manifestation. Acupuncture is effective in treating PCOS, but the differences in the biological mechanisms of acupuncture therapy and Western medicine treatment have not been determined. Thus, the purpose of this study was to find glucose metabolism-related pathways in acupuncture treatment and differentiate them from Western medical treatment. Sixty patients with PCOS-related obesity were randomly distributed into three groups: patients receiving (1) acupuncture treatment alone, (2) conventional Western medicine treatment, and (3) acupuncture combined with Western medicine treatment. A targeted metabolomics approach was used to identify small molecules and metabolites related to glucose metabolism in the serum of each group, and ultra-high-performance liquid chromatography-tandem mass spectrometry was used to analyze different metabolic fractions. The results showed acupuncture treatment modulates the activity of citric and succinic acids in the tricarboxylic acid cycle, regulates glycolytic and gluconeogenesis pathways, and improves the levels of sex hormones and energy metabolism. The intervention effects on the metabolic pathways were different between patients receiving combination therapy and patients receiving acupuncture therapy alone, suggesting that the dominant modulatory effect of Western drugs may largely conceal the efficacy of acupuncture intervention.

Remnant cholesterol is independently associated with diabetes, even if the traditional lipid is at the appropriate level: A report from the REACTION study

BACKGROUND

The association between remnant cholesterol (RC) and diabetes remains unclear because of limited study and data. This study attempted to explore the association between RC and diabetes in a large sample, multicenter general population.

METHODS

The current study included 36 684 participants from eight provinces across China. Subjects were quartered according to the RC quartile. Logistic regression analysis was used to evaluate the association between RC and diabetes.

RESULTS

After adjusting for potential confounding factors, RC was still significantly associated with diabetes (Q4: odds ratio [OR]:1.147, 95% confidence interval [CI]: 1.049-1.254, p = .003). In addition, RC and diabetes were still significantly associated when triglycerides (TG) were <1.7 mmol/L (Q4: OR: 1.155, 95% CI: 1.005-1.327, p = .042), low-density lipoprotein cholesterol (LDL-C) <3.4 mmol/L (Q4: OR: 1.130, 95% CI: 1.011-1.264, p = .032), or HDL-C (high-density lipoprotein cholesterol) ≥1.0 mmol/L (Q4: OR: 1.116, 95% CI: 1.007-1.237, p = .037). In the stratification analysis, elevated RC was significantly associated with diabetes in subjects with systolic blood pressure (SBP) <140 mm Hg and diastolic blood pressure (DBP) <90 mm Hg, 60 ≤ estimated glomerular filtration rate (eGFR) ≤90 ml/min per 1.73 m² , younger than 55 years old and female.

CONCLUSION

In the Chinese community, RC is significantly correlated with diabetes, even when TG, LDL-C, or HDL-C were controlled within the appropriate range recommended by the guidelines.

Reduced Sensitivity to Thyroid Hormones Is Associated With High Remnant Cholesterol Levels in Chinese Euthyroid Adults

CONTEXT

It remains unclear whether the thyroid system could regulate the atherogenic remnant cholesterol (RC) levels in euthyroid status.

OBJECTIVE

We aimed to investigate the relationship between sensitivity to thyroid hormones and RC levels in Chinese euthyroid population.

METHODS

This study included 18 766 euthyroid adults. High RC levels were defined as the upper quartile of RC levels. The thyroid hormone sensitivity indices, including thyroid feedback quantile-based index (TFQI), thyroid-stimulating hormone index (TSHI), thyrotrophic thyroxine resistance index (TT4RI), and free triiodothyronine to free thyroxine (FT3/FT4) ratio were calculated. Linear and binary logistic regression analysis were applied to determine the associations between those composite indices with RC levels by genders.

RESULTS

Both females and males with high RC levels exhibited co-existing higher TSH and FT4 levels. Linear regression analysis revealed that TFQI, TSHI, and TT4RI were positively, while FT3/FT4 ratio levels were negatively associated with serum RC levels. The odds ratios (ORs) (95% CI) for high RC levels were increased with rising TFQI quartiles (Q) [females: Q3 1.41 (1.22-1.63), Q4 1.61 (1.39-1.86); males: Q3 1.25 (1.09-1.45), Q4 1.38 (1.19-1.59), all P for trend < 0.001] after full adjustment, with Q1 as the reference. TSHI and TT4RI yielded similar results. By contrast, the ORs (95% CI) for high RC levels were decreased with increasing FT3/FT4 ratio quartiles in both genders (P for trend < 0.001).

CONCLUSION

In euthyroid adults, reduced sensitivity to thyroid hormones was associated with high RC levels. Our results suggested an additive cardiometabolic risk of euthyroid population with thyroid hormones insensitivity.

Remnant cholesterol for the detection of glucose metabolic states in patients with coronary heart disease angina pectoris

BACKGROUND

This study aimed to evaluate the relationship between remnant cholesterol (RC) and glucose metabolic states in coronary heart disease (CHD) patients with angina pectoris.

METHODS

This study collected data from 11,557 CHD patients with angina pectoris aged 35-75 years in Tianjin, China. Participants were divided into normal glucose regulation (NGR), prediabetes (Pre-DM) and diabetes mellitus (DM) groups according to glucose metabolic states. Linear regression analysis was used to explore the relationship between glucose metabolism [fasting blood glucose (FBG) and glycated hemoglobin (HbA1c)] and RC levels. Logistic regression was performed to analyze the relationship between RC levels and glucose metabolic states.

RESULTS

Among all participants, 5883 (50.9%) had a DM state and 4034 (34.9%) had a Pre-DM state. FBG levels and HbA1c levels were positively related with RC in all patients (P < 0.001). NGR was used as a reference, multi-adjusted model showing that RC level was significantly associated with Pre-DM [Odds ratio (OR): 1.37; 95% confidence interval (CI) 1.19-1.56; P < 0.001] and DM state (OR:1.47; 95% CI 1.29-1.67; P < 0.001). When considering RC as categorical variables (tertiles), using T1 as a reference, T3 had the strongest relationship between RC levels and Pre-DM and DM state in univariate model and multivariate model. In the stratified analyses, the association between RC levels and pre-DM and DM in women was higher than that in men, and the elderly patients was higher than in the middle-aged patients.

CONCLUSION

The study demonstrated a significant association between RC levels and pre-DM and DM state among CHD patients with angina pectoris, and the relationship was stronger in women and elderly patients.

An Updated Perspective on the Dual-Track Model of Enterocyte Fat Metabolism

The small intestinal epithelium has classically been envisioned as a conduit for nutrient absorption, but appreciation is growing for a larger and more dynamic role for enterocytes in lipid metabolism. Considerable gaps remain in our knowledge of this physiology, but it appears that the enterocyte's structural polarization dictates its behavior in fat partitioning, treating fat differently based on its absorption across the apical versus the basolateral membrane. In this review, we synthesize existing data and thought on this dual-track model of enterocyte fat metabolism through the lens of human integrative physiology. The apical track includes the canonical pathway of dietary lipid absorption across the apical brush-border membrane, leading to packaging and secretion of those lipids as chylomicrons. However, this track also reserves a portion of dietary lipid within cytoplasmic lipid droplets for later uses, including the "second-meal effect," which remains poorly understood. At the same time, the enterocyte takes up circulating fats across the basolateral membrane by mechanisms that may include receptor-mediated import of triglyceride-rich lipoproteins or their remnants, local hydrolysis and internalization of free fatty acids, or enterocyte de novo lipogenesis using basolaterally absorbed substrates. The ultimate destinations of basolateral-track fat may include fatty acid oxidation, structural lipid synthesis, storage in cytoplasmic lipid droplets, or ultimate resecretion, although the regulation and purposes of this basolateral track remain mysterious. We propose that the enterocyte integrates lipid flux along both of these tracks in order to calibrate its overall program of lipid metabolism.

The alterations of circulating mucosal-associated invariant T cells in polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder affecting reproductive age females and an important cause of infertility. Although the etiology is complex and its pathogenesis remains unclear, the pathological process of PCOS is tightly related with the immune dysfunction and gut microbial dysbiosis. Mucosal-associated invariant T (MAIT) cells are a subset of innate-like T cells which can regulate inflammation through the production of cytokines and play a role in regulating the gut microbiota. We aim to evaluate the correlation between characteristics of PCOS and MAIT cells as well as their impact on cytokine secretion.

METHODS

Peripheral blood samples were taken from PCOS patients (n=33) and healthy controls (n=30) during 2-5 days of the menstrual period. The frequencies of MAIT cells and T cells were measured by flow cytometry. Cytokines interleukin 17 (IL-17), interleukin 22(IL-22), interferon γ (IFN-γ) and granzyme B were determined by Enzyme-linked immunosorbent assay (ELISA).

RESULTS

The frequency of MAIT cells was significantly reduced in the blood of PCOS patients compared with the controls, and negatively correlated with Body Mass Index (BMI), Homeostatic model assessment- insulin resistance (HOMA-IR) index, and Anti Miillerian Hormone (AMH). Thus, the frequencies of MAIT cells decreased in PCOS patients with abnormal weight (BMI≥24kg/m2), higher HOMA-IR (≥1.5), and excessive AMH (≥8ng/ml). The Cytokine IL-17 was significantly higher in PCOS patients and negatively correlated with the frequency of MAIT cells. Even though the IL-22 was lower in PCOS Patients, no correlation with MAIT cells was detected. In subgroup, CD4+MAIT cells correlated with BMI, AMH, and testosterone (T) levels.

CONCLUSION

The frequency change of MAIT cells may play a significant role in the pathogenesis of PCOS. Exploring these interactions with MAIT cells may provide a new target for PCOS treatment and prevention.

Triglyceride Glucose-Waist Circumference Is Superior to the Homeostasis Model Assessment of Insulin Resistance in Identifying Nonalcoholic Fatty Liver Disease in Healthy Subjects

The triglyceride glucose (TyG) index has been suggested as a marker for insulin resistance; however, few studies have investigated the clinical implications of markers that combine obesity markers with the TyG index. This study aimed to investigate the associations between non-alcoholic fatty liver disease (NAFLD) and TyG-related markers in healthy subjects in Korea. We enrolled 21,001 asymptomatic participants who underwent hepatic ultrasonography. The homeostasis model assessment of insulin resistance (HOMA-IR), TyG index, TyG-body mass index, and TyG-waist circumference (WC) were subsequently analyzed. NAFLD was diagnosed using hepatic ultrasonography. A multiple logistic regression analysis was performed to evaluate the associations between the quartiles of each parameter and the risk of NAFLD. The increase in the NAFLD risk was most evident when the TyG-WC quartiles were applied; the multivariate-adjusted odds ratios for NAFLD were 4.72 (3.65–6.10), 13.28 (10.23–17.24), and 41.57 (31.66–54.59) in the 2nd, 3rd, and 4th TyG-WC quartiles, respectively, when compared with the lowest quartile. The predictability of the TyG-WC for NAFLD was better than that of the HOMA-IR using the area under the curve. The TyG-WC index was superior to the HOMA-IR for identifying NAFLD in healthy Korean adults, especially in the non-obese population.

Triglyceride Glucose-Waist Circumference Better Predicts Coronary Calcium Progression Compared with Other Indices of Insulin Resistance: A Longitudinal Observational Study

The triglyceride glucose (TyG) index, a product of triglyceride and fasting glucose, is a reliable marker for insulin resistance. We aimed to investigate the association between the TyG-related markers and coronary artery calcification (CAC) progression. We enrolled 1145 asymptomatic participants who underwent repeated CAC score measurements during routine health examinations. Homeostasis model assessment of insulin resistance (HOMA-IR), TyG index, TyG-BMI (body mass index), and TyG-WC (waist circumference) were calculated. Progression of CAC was defined as (1) incident CAC in a CAC-free population, or an (2) increase of ≥2.5 units between the baseline and final square root of the CAC scores in participants with detectable CAC. According to the quartiles of parameters, we stratified the subjects into four groups. The prevalence of progression increased with the TyG-WC quartile (15.0%, 24.1%, 31.0%, and 32.2% for each of the groups; p < 0.001). The multivariate-adjusted odds ratio (95% confidence interval) for CAC score progression was 1.66 (1.01–2.77) when the highest and lowest TyG-WC index quartiles were compared. Furthermore, the predictability of TyG-WC for CAC progression was better than the other indices in terms of the area under the curve. The TyG-WC index predicted CAC progression better than other indices and could be a potential marker of future coronary atherosclerosis.

The impact of triglycerides on glucose tolerance: Lipotoxicity revisited

Elevated plasma triglycerides (TGs) are early key features of conditions associated with a dysregulation in glucose metabolism and may predict the development of type 2 diabetes (T2D) over time. Although the acute ingestion of lipid, either mixed with or shortly before the meal, is neutral or slightly beneficial on glucose tolerance, a short-term increase in plasma TGs induced by either an i.v. lipid infusion or a high-fat diet produces a deterioration of glucose control. Accordingly, chronic lowering of plasma TGs by fibrates improves glucose homeostasis and may also prevent T2D. The chronic effects of the elevation of dietary lipid intake are less clear, particularly in humans, being the quality of fat probably more important than total fat intake. Although on the bases of the available experimental and clinical evidence it cannot be easily disentangled, with respect to elevated non-esterified fatty acids (NEFA) the relative contribution of elevated TGs to glucose homeostasis disregulation seems to be greater and also more plausible. In conclusion, although the association between elevated plasma TGs and impaired glucose tolerance is commonly considered not causative or merely a consequence of NEFA-mediated lipotoxicity, the available data suggest that TGs per se may directly contribute to disorders of glucose metabolism.

Insulin Secretory Defect and Insulin Resistance in Isolated Impaired Fasting Glucose and Isolated Impaired Glucose Tolerance

OBJECTIVE

To investigate the characteristics of isolated impaired glucose tolerance (IGT) and isolated impaired fasting glucose (IFG), we analyzed the factors responsible for elevation of 2-hour postchallenge plasma glucose (2 h PG) and fasting plasma glucose (FPG) levels.

METHODS

We investigated the relationship between 2 h PG and FPG levels who underwent 75 g OGTT in 5620 Japanese subjects at initial examination for medical check-up. We compared clinical characteristics between isolated IGT and isolated IFG and analyzed the relationships of 2 h PG and FPG with clinical characteristics, the indices of insulin secretory capacity, and insulin sensitivity.

RESULTS

In a comparison between isolated IGT and isolated IFG, insulinogenic index was lower in isolated IGT than that of isolated IFG (0.43 ± 0.34 versus 0.50 ± 0.47, resp.; p < 0.01). ISI composite was lower in isolated IFG than that of isolated IGT (6.87 ± 3.38 versus 7.98 ± 4.03, resp.; p < 0.0001). In isolated IGT group, insulinogenic index showed a significant correlation with 2 h PG (r = -0.245, p < 0.0001) and had the strongest correlation with 2 h PG (β = -0.290). In isolated IFG group, ISI composite showed a significant correlation with FPG (r = -0.162, p < 0.0001) and had the strongest correlation with FPG (β = -0.214).

CONCLUSIONS

We have elucidated that decreased early-phase insulin secretion is the most important factor responsible for elevation of 2 h PG levels in isolated IGT subjects, and decreased insulin sensitivity is the most important factor responsible for elevation of FPG levels in isolated IFG subjects.

Clinical usefulness of lipid ratios, visceral adiposity indicators, and the triglycerides and glucose index as risk markers of insulin resistance

Background

To directly compare traditional lipid ratios (total cholesterol [TC]/high density lipoprotein cholesterol [HDL-C], non-HDL-C/HDL-C, low density lipoprotein cholesterol [LDL-C]/HDL-C, and triglycerides [TG]/HDL-C), apolipoprotein B (apoB)/apolipoprotein A-I (apoA-I) ratio, visceral adiposity index (VAI), lipid accumulation product (LAP), and the product of TG and fasting glucose (TyG) for strength and independence as risk factors for insulin resistance (IR).

Methods

We conducted a cross-sectional analysis of 7629 Chinese adults using data from the China Health and Nutrition Survey 2009.

Results

For all lipid ratios (traditional lipid ratios and apoB/apoA-I), among both sexes, TG/HDL-C explained the most additional percentage of variation in HOMA-IR (2.9% in men, and 2.3% in women); for all variables of interest, the variability in HOMA-IR explained by VAI and TG/HDL-C were comparable; TyG had the most significant association with HOMA-IR, which explained 9.1% for men and 7.8% for women of the variability in HOMA-IR. Logistic regression analysis showed the similar patterns. Receiver operating characteristic (ROC) curve analysis showed that, among both sexes, TG/HDL-C was a better discriminator of IR than apoB/apoA-I; the area under the ROC curve (AUC) for VAI (0.695 in men and 0.682 in women) was greater than that for TG/HDL-C (AUC 0.665 in men and 0.664 in women); TyG presented the greatest value of AUC (0.709 in men and 0.711 in women).

Conclusion

The apoB/apoA-I performs no better than any of the traditional lipid ratios in correlating with IR. The TG/HDL-C, VAI and TyG are better markers for early identification of IR individuals.

Optimal reference interval for homeostasis model assessment of insulin resistance in a Japanese population

The aim of the present study was to establish a reference interval for homeostasis model assessment of insulin resistance (HOMA‐IR) in a Japanese population based on the C28‐A3 document from the Clinical and Laboratory Standards Institute (CLSI). We selected healthy subjects aged 20–79 years, with fasting plasma glucose < 100 mg/dL, body mass index < 25 kg/m² and alanine aminotransferase < 31 U/L. HOMA‐IR values were log transformed, values beyond mean ± 3 standard deviations (SD) were truncated, and the mean ± 2 SD of log HOMA‐IR values were taken as the upper and lower reference limits of HOMA‐IR. We selected 2173 subjects as reference individuals, and 2153 subjects were used for analysis. The reference interval for HOMA‐IR was established as between 0.4 and 2.4. This represents the first reference interval study for HOMA‐IR that applies the stringent CLSI C28‐A3 document. HOMA‐IR ≥ 2.5 should be considered a reasonable indicator of insulin resistance in Japanese. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00113.x, 2011)

Insulin secretory capacity and insulin sensitivity in impaired fasting glucose in Japanese

Aims/Introduction:  Impaired fasting glucose (IFG) increases the risk of developing diabetes mellitus (DM). This study was carried out to characterize Japanese patients who have fasting glucose levels (FPG) between 100 and 109 mg/dL (IFG_100–109).

Materials and Methods:  A total of 1383 Japanese participants were examined by oral glucose tolerance test. We compared insulin secretory capacity (insulinogenic index) and insulin sensitivity (ISI composite) of IFG_100–109/normal glucose tolerance (NGT; 100 ≤ FPG < 110 mg/dL and 2‐h postchallenge glucose level (2‐hPG) < 140 mg/dL) with NGT (100 mg/dL < FPG and 2‐hPG < 140 mg/dL) and IFG_110–125/NGT (110 ≤ FPG < 126 mg/dL and 2‐hPG < 140 mg/dL). In addition, IFG_100–109 patients were analyzed in three subgroups according to glucose intolerance by 2‐hPG.

Results:  Of the three categories of IFG_100–109, IFG_100–109/DM had the lowest insulinogenic index despite an ISI composite showing only a small decline from IFG_100–109/NGT through IFG_100–109/IGT (100 ≤ FPG < 110 mg/dL and 140 ≤ 2‐hPG < 200 mg/dL) to IFG_100–109/DM (100 ≤ FPG < 110 mg/dL and 200 mg/dL < 2‐hPG). By multiple regression analysis, the insulinogenic index showed a significant relationship with 2‐h PG levels. Both insulinogenic index and ISI composite were decreased significantly from NGT through IFG_100–109/NGT to IFG_110–125/NGT.

Conclusions:  Although impaired early‐phase insulin secretion plays the more important role in the elevation of postchallenge glucose in IFG_100–109 patients, both impaired early‐phase insulin secretion and decreased insulin sensitivity are involved in the deterioration of FPG in Japanese. In addition, insulin secretory defect and decreased insulin sensitivity already have begun in patients with IFG_100–109.(J Diabetes Invest, doi: 10.1111/j.2040‐1124.2012.00201.x, 2012)

Relationship and factors responsible for regulating fasting and post-challenge plasma glucose levels in the early stage development of type 2 diabetes mellitus

AIMS/INTRODUCTION

Elevation of 2-h plasma glucose (2-h PG) levels keeps step with fasting plasma glucose (FPG) levels elevation, but some individuals show dominant elevation of 2-h PG and others FPG. We analyzed dependent and independent relationships between 2-h PG and FPG, and investigated the factors regulating 2-h PG and FPG.

MATERIALS AND METHODS

In 1,657 Japanese participants who underwent a 75-g oral glucose tolerance test at the initial examination for a medical check-up, we carried out simple linear regression analysis between 2-h PG and FPG levels on the three patterns of independent variables. We divided the participants into two subgroups: the 2-h PG-side group and the FPG-side from the regression line, and examined the relationships between 2-h PG-FPG and factors responsible for elevation of plasma glucose levels.

RESULTS

There was a significant positive correlation between 2-h PG and FPG levels. The regression line of both 2-h PG and FPG as independent variables was in accordance with the regression line of 2-h PG as an independent variable and FPG as a dependent variable. In 2-h PG-side group, age was the independent factor affecting 2-h PG in addition to insulinogenic index and insulin sensitivity index (ISI composite). In the FPG-side group, triglyceride was the independent factor affecting FPG in addition to insulinogenic index and ISI composite.

CONCLUSIONS

Two-hour PG was an independent predictor of FPG. In addition to the importance of decreased insulin secretion and insulin sensitivity, age was the strong factor to elevate 2-h PG levels in the 2-h PG-side group and triglyceride was the strong factor to elevate FPG levels in the FPG-side group in the early stage of development of type 2 diabetes.

Effects of insulin resistance on white matter microstructure in middle-aged and older adults

OBJECTIVE

To investigate the potential relationship between insulin resistance (IR) and white matter (WM) microstructure using diffusion tensor imaging in cognitively healthy middle-aged and older adults.

METHODS

Diffusion tensor imaging was acquired from 127 individuals (age range 41-86 years). IR was evaluated by the homeostasis model assessment of IR (HOMA-IR). Participants were divided into 2 groups based on HOMA-IR values: "high HOMA-IR" (≥2.5, n = 27) and "low HOMA-IR" (<2.5, n = 100). Cross-sectional voxel-based comparisons were performed using Tract-Based Spatial Statistics and anatomically defined regions of interest analysis.

RESULTS

The high HOMA-IR group demonstrated decreased axial diffusivity broadly throughout the cerebral WM in areas such as the corpus callosum, corona radiata, cerebral peduncle, posterior thalamic radiation, and right superior longitudinal fasciculus, and WM underlying the frontal, parietal, and temporal lobes, as well as decreased fractional anisotropy in the body and genu of corpus callosum and parts of the superior and anterior corona radiata, compared with the low HOMA-IR group, independent of age, WM signal abnormality volume, and antihypertensive medication status. These regions additionally demonstrated linear associations between diffusion measures and HOMA-IR across all subjects, with higher HOMA-IR values being correlated with lower axial diffusivity.

CONCLUSIONS

In generally healthy adults, greater IR is associated with alterations in WM tissue integrity. These cross-sectional findings suggest that IR contributes to WM microstructural alterations in middle-aged and older adults.

Improvement of glycated hemoglobin in Japanese subjects with type 2 diabetes by resolution of periodontal inflammation using adjunct topical antibiotics: results from the Hiroshima Study

AIMS

Periodontal treatment reduces glycated hemoglobin (HbA1) in subjects with type 2 diabetes, although effective strategy for different severities of periodontitis remains unclear. We hypothesized that resolution of periodontitis-induced inflammation by the therapy combined with antibiotics may have beneficial effects on the glycemic control of diabetes.

METHODS

A total of 523 subjects with type 2 diabetes were screened for periodontal disease. Of these, 160 subjects who visited dentists were divided into two groups according to high-sensitivity c-reactive protein (hsCRP) level: >500 ng/ml and <500 ng/ml. The group with hsCRP over 500 ng/ml was further sub-divided into two groups according to treatment strategy: topical application of antibiotics combined with conventional mechanical debridement (group A), and debridement alone (B). Subjects with hsCRP below 500 ng/ml were sub-divided similarly (C: combination therapy; D: debridement alone). hsCRP was measured after 1 month and changes of HbA1c after 3 months. These parameters were also measured in control subjects (N=118) who did not visit dentists (E: initial hsCRP>500 ng/ml; F: hsCRP<500 ng/ml).

RESULTS

A multiple comparison by ANOVA revealed that only group A showed a significant reduction in HbA1c over time (P<0.001). Multivariable analyses revealed elevated hsCRP and the combination treatment with antibiotics were two independent variables influencing the decrease of HbA1c over the study (P<0.01 and P<0.001, respectively).

CONCLUSIONS

In subjects with type 2 diabetes and periodontitis-induced mild inflammation (hsCRP>500 ng/ml), treatment to reduce hsCRP using antibiotics is recommended.

Upregulation of hepatic LRP1 by rosiglitazone: a possible novel mechanism of the beneficial effect of thiazolidinediones on atherogenic dyslipidemia

Hepatic LDL receptor-related protein 1 (LRP1) plays a role in the clearance of circulating remnant lipoproteins. In this study, we investigated the effect of rosiglitazone treatment on the expression and function of hepatic LRP1. HepG2 cells were incubated with various concentrations of rosiglitazone. Male Long-Evans Tokushima Otsuka (LETO) rats and Otsuka-Long-Evans-Tokushima Fatty (OLETF) rats were treated with rosiglitazone for 5 weeks. The expression and function of LRP1 in HepG2 cells and liver samples of rats were analyzed. LRP1 mRNA and protein expressions were increased by 0.5 and 5  μM rosiglitazone in HepG2 cells. However, at concentrations above 50  μM rosiglitazone, LRP1 mRNA and protein expressions did not change compared with those in nontreated cells. Reporter assay showed that 0.5 and 5  μM rosiglitazone increased the transcriptional activity of the LRP1 promoter in HepG2 cells. The uptake of apolipoprotein E through LRP1 in HepG2 cells was also increased by rosiglitazone. Hepatic LRP1 was reduced in OLETF rats compared with that of LETO rats and rosiglitazone treatment increased hepatic LRP1 in OLETF rats. A high glucose condition (25  mM glucose in culture media) reduced the expression of LRP1 in HepG2 cells, and this reduced LRP1 expression was recovered with rosiglitazone. In conclusion, our data suggest that decreased hepatic LRP1 in a diabetic condition is associated with the development of atherogenic dyslipidemia and that increased hepatic LRP1 by thiazolidinediones could contribute to an improvement in atherogenic lipid profiles in diabetic patients.

Association between insulin resistance and metabolic syndrome risk factors in Japanese

Aims/Introduction:  It is important to identify individuals at risk of metabolic syndrome (MetS), namely those with insulin resistance. Therefore, the aim of the present study was to find anthropometric and metabolic parameters that can better predict insulin resistance.

SUBJECTS AND METHODS

  We selected 3899 individuals (2058 men and 1841 women), excluding those with fasting plasma glucose (FPG) ≥126 mg/dL, on medication for hypertension, dyslipidemia or diabetes, and those with a history of advanced macrovascular disease. Using multivariate analyses, we selected components for obesity, lipids, and blood pressure based on the strength of their association with the homeostasis model assessment of insulin resistance (HOMA-IR).

RESULTS

  In multiple linear regression analysis, body mass index (BMI), waist circumference (WC), triglycerides (TG), high-density lipoprotein-cholesterol (HDL-C), and systolic blood pressure (SBP) were selected in men and women, and the effect of BMI on HOMA-IR outweighed that of WC. In multiple logistic regression analysis, BMI, TG, and SBP were significantly associated with HOMA-IR ≥2.5 in both genders, but WC and HDL-C were only selected in men. Combinations of BMI, TG, SBP, and FPG showed higher HOMA-IR values than those of the existing MetS components, considered useful for the identification of individual with higher insulin resistance.

CONCLUSIONS

  Body mass index, TG and SBP were selected as components significantly related to insulin resistance. The selected components were fundamentally adherent to the existing MetS criteria, the only difference being the measure of obesity, in which a stronger association with insulin resistance was observed for BMI than WC. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00162.x, 2011).

The effects of rosiglitazone and metformin on inflammation and endothelial dysfunction in patients with type 2 diabetes mellitus

Diabetic patients have a markedly increased risk of cardiovascular disease compared with non-diabetics. Two drug groups today target insulin resistance; biguanides and thiazolidinediones. In addition, these may have other effects on cardiovascular risk factors. The aim of this study was to evaluate the effects of metformin and rosiglitazone on non-traditional cardiovascular risk factors. Forty type 2 diabetic patients were randomized into metformin and rosiglitazone groups. After receiving the optimal doses, the patients were monitored for 12 weeks. Biochemical parameters, lipid parameters, CRP, insulin, c-peptide, and HbA1c levels were analyzed. VWF, PAI-1, ICAM-1, TNF-α, IL-6, E-selectin, and fibrinogen levels were measured in order to assess coagulation status and endothelial dysfunction. In the metformin group, body mass index, PPG, HbA1c, IL-6, ICAM-1, and TNF-α levels were significantly decreased after 12 weeks compared with the basal levels. IL-6 levels decreased from 75 pg/ml ± 20 to 42 pg/ml ± 9 (P 0.023) and TNF- α levels from 61 pg/ml ± 31 to 39 pg/ml ± 10 (P 0.018). In the rosiglitazone group, FPG, PPG, HbA1c, insulin, HOMA-IR, IL-6, and TNF-α levels decreased significantly after 12 weeks compared with the basal levels. IL-6 levels decreased from 78 pg/ml ± 21 to 41 pg/ml ± 9 (P 0.028) and TNF-α levels from 62 pg/ml ± 19 to 37 pg/ml ± 10 (P 0.012). At the end of the study, no significant differences were determined between groups. Insulin resistance and type 2 diabetes are strongly associated with low grade inflammation. Both metformin and rosiglitazone were effective in controlling inflammatory markers in addition to metabolic parameters.

Effects of acute hyperglucagonemia on hepatic and intestinal lipoprotein production and clearance in healthy humans

OBJECTIVE

The metabolism of hepatic- and intestinally derived lipoproteins is regulated in a complex fashion by nutrients, hormones, and neurologic and other factors. Recent studies in animal models suggest an important role for glucagon acting via the glucagon receptor in regulating hepatic triglyceride (TG) secretion. Here we examined the direct effects of glucagon on regulation of hepatic and intestinal lipoprotein metabolism in humans.

RESEARCH DESIGN AND METHODS

Eight healthy men underwent two studies each, in random order, 4-6 weeks apart in which de novo lipogenesis, kinetics of larger VLDL1 TG, and kinetics of VLDL1 and smaller VLDL2 apolipoprotein (apo)B100 and B48 were studied using established stable isotope enrichment methods. Subjects were studied in the constant fed state under conditions of a pancreatic clamp (with infusion of somatostatin, insulin, and growth hormone) at either basal glucagon (BG study, 64.5 ± 2.1 pg/mL) or hyperglucagonemia (high glucagon [HG] study, 183.2 ± 5.1 pg/mL).

RESULTS

There were no significant differences in plasma concentration of VLDL1 or VLDL2 TG, apoB100 or apoB48 between BG and HG studies. There was, however, lower (P < 0.05) VLDL1 apoB100 fractional catabolic rate (-39%) and production rate (-30%) in HG versus BG, but no difference in de novo lipogenesis or TG turnover, and glucagon had no effect on intestinal (B48-containing) lipoprotein metabolism.

CONCLUSIONS

Glucagon acutely regulates hepatic but not intestinal lipoprotein particle metabolism in humans both by decreasing hepatic lipoprotein particle production as well as by inhibiting particle clearance, with no net effect on particle concentration.

Hepatocyte growth factor is a significant risk factor for white matter lesions in Japanese type 2 diabetic patients

BACKGROUND

The presence of white matter lesions (WML) is an important prognostic factor for the development of stroke. Elevated hepatocyte growth factor (HGF) levels are associated with a high mortality rate in type 2 diabetic patients. The preliminary study was therefore designed to test the hypothesis that the presence of WML correlates with HGF and insulin resistance in type 2 diabetic patients not receiving insulin treatment.

MATERIAL AND METHODS

Based on brain magnetic resonance imaging, 92 type 2 diabetic patients were divided into two groups: WML-positive group (age 60 +/- 5 years, mean +/- SD, n = 35) and WML-negative group (age 59 +/- 6 years, mean +/- SD, n = 57. The level of blood glucose was assessed by fasting plasma glucose, fasting immunoreactive insulin, homeostasis model assessment (HOMA) index and haemoglobin A1c (HbA1c).

RESULTS

The body mass index was higher in the WML-positive group than that in the WML-negative group (P < 0.005). Plasma levels of triglycerides were higher while high-density lipoprotein cholesterol was lower in the WML-positive group than in the WML-negative group (P < 0.01 and P < 0.0001 respectively). Fasting plasma glucose (P < 0.0001), insulin concentrations (P < 0.0001), HOMA index (P < 0.0001) and HGF (< 0.0001) levels were higher in the WML-positive group than in the WML-negative group. Multivariate logistic analysis revealed that WML was independently predicted by the high HGF and insulin resistance (P < 0.0001 and P < 0.0001 respectively).

CONCLUSION

The results of this preliminary study indicate that the presence of WML was associated with the high HGF and insulin resistance in Japanese patients with type 2 diabetes mellitus.

Diabetic retinopathy is associated with visceral fat accumulation in Japanese type 2 diabetes mellitus patients

The presence of diabetic retinopathy (DR) and increased of visceral fat accumulation (VFA) are associated with high mortality in type 2 diabetes mellitus patients. This preliminary study was therefore designed to test the hypothesis that DR is associated with insulin resistance and VFA in type 2 diabetes mellitus patients without insulin treatment. A total of 102 type 2 diabetes mellitus patients were divided into 2 groups: DR group (age, 60 +/- 6 years [mean +/- SD]; n = 31) and no diabetic retinopathy (NDR) group (59 +/- 5 years, n = 71). The level of blood glucose was assessed by fasting plasma glucose, fasting immunoreactive insulin, homeostasis model assessment index, and hemoglobin A(1c). The fat distribution was evaluated by measuring the VFA by abdominal computed tomography at the umbilical level. The body mass index and waist circumference were higher in the DR group than in the NDR group (P < .001 and P < .0005, respectively). Plasma levels of triglyceride were higher, whereas high-density lipoprotein cholesterol was lower, in the DR group than in the NDR group (P < .005 and P < .0001, respectively). Fasting plasma glucose (P < .0005), insulin concentrations (P < .0001), homeostasis model assessment index (P < .0001), and VFA (P < .0001) levels were higher in the DR group than in the NDR group. Multivariate logistic analysis revealed that DR was independently predicted by high VFA and insulin resistance. The results of this preliminary study indicate that the presence of DR was associated with high VFA and insulin resistance in Japanese patients with type 2 diabetes mellitus.

Insulin acutely inhibits intestinal lipoprotein secretion in humans in part by suppressing plasma free fatty acids

OBJECTIVE

Intestinal lipoprotein production has recently been shown to be increased in insulin resistance, but it is not known whether it is regulated by insulin in humans. Here, we investigated the effect of acute hyperinsulinemia on intestinal (and hepatic) lipoprotein production in six healthy men in the presence and absence of concomitant suppression of plasma free fatty acids (FFAs).

RESEARCH DESIGN AND METHODS

Each subject underwent the following three lipoprotein turnover studies, in random order, 4-6 weeks apart: 1) insulin and glucose infusion (euglycemic-hyperinsulinemic clamp) to induce hyperinsulinemia, 2) insulin and glucose infusion plus Intralipid and heparin infusion to prevent the insulin-induced suppression of plasma FFAs, and 3) saline control.

RESULTS

VLDL1 and VLDL2-apoB48 and -apoB100 production rates were suppressed by 47-62% by insulin, with no change in clearance. When the decline in FFAs was prevented by concomitant infusion of Intralipid and heparin, the production rates of VLDL1 and VLDL2-apoB48 and -apoB100 were intermediate between insulin and glucose infusion and saline control.

CONCLUSIONS

This is the first demonstration in humans that intestinal apoB48-containing lipoprotein production is acutely suppressed by insulin, which may involve insulin's direct effects and insulin-mediated suppression of circulating FFAs.

Association between plasma high-sensitivity C-reactive protein and insulin resistance and white matter lesions in Japanese type 2 diabetic patients

The presence of white matter lesions (WML) is an important prognostic factor for the development of stroke. High-sensitivity C-reactive protein (HSCRP), which is associated with diabetes, has been flagged as a novel predictor for cerebrovascular events. This preliminary study was therefore designed to test the hypothesis that the presence of WML correlates with HSCRP and insulin resistance in type 2 diabetic patients not receiving insulin treatment. Based on brain magnetic resonance imaging (MRI) findings, 102 type 2 diabetic patients were divided into two groups; a WML-positive group (59+/-6 years, mean+/-SD, n=40) and a WML-negative group (58+/-6 years, n=62). The level of blood glucose was assessed by fasting plasma glucose (FPG), fasting immunoreactive insulin (F-IRI), homeostasis model assessment (HOMA) index, and Hemoglobin A1c (HbA1c). The body mass index was higher in the WML-positive group than in the WML-negative group (p<0.05). Plasma levels of triglycerides were higher while high-density lipoprotein cholesterol (HDL-C) was lower in the WML-positive group than in the WML-negative group (p<0.01 and p<0.005, respectively). Fasting plasma glucose (p<0.005), insulin concentrations (p<0.0001), HOMA index (p<0.0001), and HSCRP (<0.0001) levels were higher in the WML-positive group than in the WML-negative group. Multivariate logistic analysis revealed that WML was independently predicted by the high HSCRP and insulin resistance (p<0.005, p<0.0005, respectively). The results of this preliminary study indicate that the presence of WML was associated with the high HSCRP and insulin resistance in these Japanese patients with type 2 diabetes mellitus; larger cohort studies are warranted to confirm these findings.

Neferine enhances insulin sensitivity in insulin resistant rats

ETHNOPHARMACOLOGICAL RELEVANCE

Neferine was isolated from green seed embryo of Nelumbo nucifera Gaertn which has been used as an anti-obesity agent in traditional Chinese herbal medicine.

AIM OF THE STUDY

This study was conducted to investigate the effects of neferine on enhancing insulin sensitivity in insulin resistant rats compared with rosiglitazone and to potentially reveal its role in mediating the anti-obesity properties of Nelumbo nucifera Gaertn.

MATERIALS AND METHODS

Fasting blood glucose (FBG), fasting blood insulin (FINS), triglycerides (TG) and tumor necrosis factor-alpha (TNF-alpha) were measured, and the oral glucose tolerance test for 2-h plasma glucose level (2-h PG) was carried out. The glucose infusion rate (GIR) was used to measure the insulin sensitivity by hyperinsulinemic euglycemic clamp technique.

RESULTS

The levels of FBG, FINS, TG, TNF-alpha and 2-h PG all decreased significantly in the rosiglitazone and neferine groups compared with the insulin resistance (IR) model group. Neferine diminished the 2-h PG more than did rosiglitazone treatment. Compared to the IR model group, the treatments of neferine and rosiglitazone remarkably increased GIRs but no difference between these two treatments themselves was evident.

CONCLUSIONS

These data demonstrate that neferine has effects similar to rosiglitazone in decreasing fasting blood glucose, insulin, TG, TNF-alpha and enhancing insulin sensitivity in insulin resistant rats.

Visceral fat accumulation is a significant risk factor for white matter lesions in Japanese type 2 diabetic patients

BACKGROUND

The presence of white matter lesions (WML) is an important prognostic factor for the development of stroke. The elevated visceral fat accumulation (VFA) has been reported to be closely related to the development of atherosclerosis. This preliminary study was therefore designed to test the hypothesis that the presence of WML correlates with VFA and insulin resistance in type 2 diabetic patients not receiving insulin treatment.

MATERIAL AND METHODS

Based on brain magnetic resonance imaging (MRI), 95 type 2 diabetic patients were divided into two groups: WML-positive group (aged 59 +/- 7 years, mean +/- SD n = 37) and WML-negative group (aged 58 +/- 5, years, n = 58). The level of blood glucose was assessed by fasting plasma glucose (FPG), fasting immunoreactive insulin, homeostasis model assessment (HOMA) index, and haemoglobin A1c. The fat distribution was evaluated by measuring the visceral fat accumulation by abdominal computerized tomography at the umbilical level.

RESULTS

The body mass index was higher in the WML-positive group than in the WML-negative group (P < 0.005). Plasma levels of triglycerides were higher while high-density lipoprotein cholesterol was lower in the WML-positive group than in the WML-negative group (P < 0.05 and P < 0.01, respectively). FPG (P < 0.01), insulin concentrations (P < 0.0001), HOMA index (P < 0.0001) and VFA (<0.0001) levels were higher in the WML-positive group than in the WML-negative group. Multivariate logistic analysis revealed that WML was independently predicted by the high VFA and insulin resistance (P < 0.001, P < 0.0001, respectively).

CONCLUSIONS

The results of this preliminary study indicate that the presence of WML was associated with the high VFA and insulin resistance in Japanese patients with type 2 diabetes mellitus. Further larger cohort studies are warranted to confirm these findings.

Factors responsible for elevation of 1-h postchallenge plasma glucose levels in Japanese men

The 1-h postchallenge plasma glucose (1-h PG) level is considered to be a good index of the development of glucose intolerance and type 2 diabetes as well as of diabetic complications. In some cases, in Japanese, 1-h PG is elevated despite normal fasting glucose during oral glucose tolerance test (OGTT), but the factors responsible remain unclear. In the present study, subjects with normal glucose tolerance (NGT), isolated impaired fasting glucose (IFG), and isolated impaired glucose tolerance (IGT) were divided into subgroups at 1-h PG of 10.0mM, and the four indices of insulin secretion and insulin sensitivity were compared. In all three categories, the insulinogenic index in subjects with elevated 1-h PG was remarkably lower than in those without elevated 1-h PG. In addition, the insulinogenic index was the strongest factor in elevated 1-h PG according to the multiple regression analysis. Interestingly, one third of the NGT subjects enrolled in this study had elevated 1-h PG. These subjects showed significantly elevated area under the curve of glucose (G-AUC) compared to NGT subjects without 1-h PG elevation. Thus, elevated 1-h PG in Japanese subjects indicates mildly impaired glucose tolerance due to decreased early-phase insulin secretion.

Intestinal lipoprotein overproduction in insulin-resistant states

PURPOSE OF REVIEW

Excessive postprandial lipemia is highly prevalent in obese and insulin-resistant/type 2 diabetic individuals and substantially increases the risk of atherosclerosis and cardiovascular disease. This article will review our current understanding of the link between insulin resistance and intestinal lipoprotein overproduction and highlight some of the key recent findings in the field.

RECENT FINDINGS

Emerging evidence from several animal models of insulin resistance as well as insulin-resistant humans clearly supports the link between insulin resistance and aberrant intestinal lipoprotein metabolism. In insulin-resistant states, elevated free fatty acid flux into the intestine, downregulation of intestinal insulin signaling and upregulation of microsomal triglyceride transfer protein all appear to stimulate intestinal lipoprotein production. Gut peptides, GLP-1 and GLP-2, may be important regulators of intestinal lipid absorption and lipoprotein production.

SUMMARY

Available evidence in humans and animal models strongly favors the concept that the small intestine is not merely an absorptive organ but rather plays an active role in regulating the rate of production of triglyceride-rich lipoproteins. Metabolic signals in insulin resistance and type 2 diabetes and in some cases an aberrant intestinal response to these factors all contribute to the enhanced formation and secretion of triglyceride-rich lipoproteins.

The role of microalbuminuria and insulin resistance as significant risk factors for white matter lesions in Japanese type 2 diabetic patients

OBJECTIVE

The presence of white matter lesions (WML) is an important prognostic factor for the development of stroke. Microalbuminuria, which is associated with diabetes, has been flagged as a novel predictor for cerebrovascular events. This preliminary study was therefore designed to test the hypothesis that the presence of WML correlates with microalbuminuria and insulin resistance in patients with type 2 diabetic mellitus (DM) not receiving insulin treatment.

PATIENTS AND METHODS

Based on brain magnetic resonance imaging (MRI) findings, 90 type 2 diabetic patients were divided into two groups: a WML-positive group (57+/-8 years, mean+/-SD, n=34) and a WML-negative group (57+/-6 years, n=56). The level of blood glucose was assessed by fasting plasma glucose (FPG), fasting immunoreactive insulin (F-IRI), homeostasis model assessment (HOMA) index, and hemoglobin A(1c) (HbA1c).

RESULTS

The body mass index was higher in the WML-positive group than in the WML-negative group (p<0.01). Plasma levels of triglycerides were higher while high-density lipoprotein cholesterol (HDL-C) was lower in the WML-positive group than in the WML-negative group (p<0.05 and p<0.0001, respectively). Fasting plasma glucose (p<0.005), insulin concentrations (p<0.0001), HOMA index (p<0.0001), and urinary albumin excretion (p<0.0001) levels were higher in the WML-positive group than in the WML-negative group. Multivariate logistic analysis revealed that WML was independently predicted by the microalbuminuria and insulin resistance (p<0.005, p<0.0005, respectively).

CONCLUSION

The results of this preliminary study indicate that the presence of WML was associated with the microalbuminuria and insulin resistance in these Japanese patients with type 2 DM; larger cohort studies are warranted to confirm these findings.

Both intestinal and hepatic lipoprotein production are stimulated by an acute elevation of plasma free fatty acids in humans

BACKGROUND

Hepatic lipoprotein production has been shown previously to be regulated by free fatty acid (FFA) flux to the liver, whereas intestinal lipoprotein production is stimulated mainly by ingested fat absorbed from the intestinal lumen. Emerging evidence indicates that intestinal lipoprotein production is increased in insulin resistance and type 2 diabetes mellitus, conditions that are associated with increased levels of circulating FFAs. Here we investigated whether short-term elevation of plasma FFAs stimulates intestinal apolipoprotein (apo) B-48- and hepatic apoB-100-containing triglyceride-rich lipoprotein (TRL) production in humans in the fed state.

METHODS AND RESULTS

TRL apoB-48 and apoB-100 metabolism were examined in 12 healthy men during a constant fed state. The studies were as follows, respectively: (1) Intralipid/heparin was infused intravenously immediately before and during the kinetics study to induce an approximately 3-fold difference in plasma FFA compared with the saline study; (2) saline was infused intravenously as a control. ApoB-48- and apoB-100-containing TRL production and clearance were determined with a 12-hour primed constant infusion of [D3]L-leucine and multicompartmental kinetic modeling. TRL apoB-48 production rate was 69% higher in the Intralipid/heparin study than in the saline control (5.95+/-1.13 versus 3.53+/-0.58 mg/kg per day; P=0.027), and there was no significant difference in TRL apoB-48 clearance. TRL apoB-100 concentrations were also increased (P<0.001) and TRL apoB-100 production rate was 35% higher in the Intralipid/heparin study compared with saline (28+/-4 versus 21+/-3 mg/kg per day; P=0.020).

CONCLUSIONS

This is the first study to demonstrate that intestinal TRL apoB-48 production is increased after short-term elevation of plasma FFAs in humans in the fed state, similar to the well-described stimulation of hepatic TRL apoB100-containing particles by FFAs.

Both intestinal and hepatic lipoprotein production are stimulated by an acute elevation of plasma free fatty acids in humans

BACKGROUND

Hepatic lipoprotein production has been shown previously to be regulated by free fatty acid (FFA) flux to the liver, whereas intestinal lipoprotein production is stimulated mainly by ingested fat absorbed from the intestinal lumen. Emerging evidence indicates that intestinal lipoprotein production is increased in insulin resistance and type 2 diabetes mellitus, conditions that are associated with increased levels of circulating FFAs. Here we investigated whether short-term elevation of plasma FFAs stimulates intestinal apolipoprotein (apo) B-48- and hepatic apoB-100-containing triglyceride-rich lipoprotein (TRL) production in humans in the fed state.

METHODS AND RESULTS

TRL apoB-48 and apoB-100 metabolism were examined in 12 healthy men during a constant fed state. The studies were as follows, respectively: (1) Intralipid/heparin was infused intravenously immediately before and during the kinetics study to induce an approximately 3-fold difference in plasma FFA compared with the saline study; (2) saline was infused intravenously as a control. ApoB-48- and apoB-100-containing TRL production and clearance were determined with a 12-hour primed constant infusion of [D3]L-leucine and multicompartmental kinetic modeling. TRL apoB-48 production rate was 69% higher in the Intralipid/heparin study than in the saline control (5.95+/-1.13 versus 3.53+/-0.58 mg/kg per day; P=0.027), and there was no significant difference in TRL apoB-48 clearance. TRL apoB-100 concentrations were also increased (P<0.001) and TRL apoB-100 production rate was 35% higher in the Intralipid/heparin study compared with saline (28+/-4 versus 21+/-3 mg/kg per day; P=0.020).

CONCLUSIONS

This is the first study to demonstrate that intestinal TRL apoB-48 production is increased after short-term elevation of plasma FFAs in humans in the fed state, similar to the well-described stimulation of hepatic TRL apoB100-containing particles by FFAs.

Short-term intensive glycemic control improves vibratory sensation in type 2 diabetes

Strict long-term glycemic control has been reported to prevent or improve diabetic peripheral neuropathy, but the effects of short-term glycemic control have not been clarified in patients with type 2 diabetes. To investigate reversibility of impaired vibratory sensation by short-term glycemic control, we used the TM31 liminometer and C64 tuning fork methods to measure peripheral neuropathy. Thirty-one type 2 diabetes patients with poor glycemic control (HbA1c: 10.8+/-0.4%, mean+/-S.E.M., range from 7.9% to 16.2%) were administered strict glycemic control. Vibratory sensation before and after short-term glycemic control was evaluated, and the metabolic profile including plasma glucose, HbA1c, total cholesterol, HDL cholesterol, triglyceride, and free fatty acid (FFA) was measured. After 20.0+/-2.1 days of strict glycemic control, vibratory sensation improved significantly in both upper and lower extremities, assessed by TM31 liminometer and C64 tuning fork. Along with the improved glycemic control, lipid metabolism (total cholesterol, triglyceride and FFA) was significantly improved. Thus, short-term intensive glycemic control can improve vibratory sensation, metabolic changes in glucose and lipid metabolism being the factors responsible for improved of peripheral nerve function.

Reduced high-molecular-weight adiponectin and elevated high-sensitivity C-reactive protein are synergistic risk factors for metabolic syndrome in a large-scale middle-aged to elderly population: the Shimanami Health Promoting Program Study

OBJECTIVE

In Western countries, one of the most important modifiable targets for the prevention of cardiovascular diseases is metabolic syndrome. Adiponectin is an adipose tissue-specific plasma protein that inversely associates with metabolic syndrome. Among several molecular isoforms, high-molecular-weight (HMW) complex is considered the active form. Increased serum high-sensitivity C-reactive protein (hsCRP) concentration also associates with metabolic syndrome, and adiponectin could modulate plasma C-reactive protein levels. Here, through cross-sectional investigation, we investigated whether reduced HMW adiponectin and increased hsCRP levels in plasma are synergistically associated with metabolic syndrome. Measurement of HMW complex of adiponectin is one of the novelties of this study.

DESIGN

We analyzed 1845 community-dwelling middle-aged to elderly subjects (62+/-13 yr). Plasma HMW adiponectin levels were measured by ELISA. Clinical parameters were obtained from the subjects' personal health records, evaluated at their annual medical check-up.

RESULTS

Each component of metabolic syndrome, except for raised blood pressure, showed significantly lower plasma HMW adiponectin concentrations for both men and women (P<0.001). In contrast, plasma hsCRP levels were significantly higher in subjects with metabolic disorders (P<0.001). After adjusting for other confounding factors, HMW adiponectin [log normalized, odds ratio 0.084 (95% confidence interval 0.050-0.142), P<0.001] and hsCRP [3.009 (2.175-4.163), P<0.001] were identified as independent determinants of metabolic syndrome. In addition to the direct associations, we also observed a synergistic effect between these two molecules (F=11.8, P<0.001).

CONCLUSIONS

Reduced HMW adiponectin and elevated hsCRP are synergistically associated with the accumulation of metabolic disorders. The combination of these markers would be useful for identifying at-risk populations.

Factors responsible for age-related elevation in fasting plasma glucose: a cross-sectional study in Japanese men

To evaluate the factors associated with age-related increase in fasting plasma glucose (FPG) in Japanese men with normal fasting glucose, we measured FPG, fasting immunoreactive insulin, glycated hemoglobin, total cholesterol, triglyceride, and high-density lipoprotein cholesterol levels in health check examinees. Subjects with FPG less than 6.1 mmol/L together with glycated hemoglobin less than 5.6% were enrolled in the study. The homeostasis model assessment of insulin resistance (HOMA-IR) and HOMA-beta were used as the indices of insulin sensitivity and insulin secretion, respectively. Fasting plasma glucose increased significantly with age (r = 0.30, P < .0001), and HOMA-beta decreased significantly with age (r = 0.24, P < .0001). The HOMA-IR had no significant relation with age (r = 0.06, not significant), whereas body mass index and serum triglyceride were associated with HOMA-IR (r = 0.49, P < .0001 and r = 0.33, P < .0001, respectively). Thus, in Japanese male subjects with normal fasting glucose, it is suggested that the FPG increment with age is associated with decreased beta-cell function rather than with insulin resistance. Further analyses were performed by comparing 3 groups: low FPG (FPG <5.0 mmol/L), high FPG (5.0 < or = FPG < 5.6 mmol/L), and mild impairment of fasting glycemia (mild IFG) (5.6 < or = FPG < 6.1 mmol/L). The insulin levels in mild IFG and high FPG were significantly higher than in low FPG (P < .001), but those in mild IFG were similar to those in high FPG. Analysis of the 3 subgroups revealed that, whereas insulin sensitivity was impaired more in high FPG, there was little compensatory increase in insulin in mild IFG, suggesting that beta-cell function is already deteriorated when the FPG level is greater than 5.6 mmol/L.

Factors responsible for the evolution of insulin resistance in Japanese type 2 diabetic patients: association with atherosclerosis

Type 2 diabetes is a heterogeneous syndrome characterized by defective insulin secretion and/or insulin resistance. In distinct from Caucasian populations, Japanese type 2 diabetic patients are divided into two categories: one with insulin resistance and the other with normal insulin sensitivity. This unique feature allows us to explore the factors responsible for the evolution of insulin resistance in Japanese type 2 diabetic patients. In this article, we describe the factors responsible for insulin resistance in Japanese type 2 diabetic patients and discuss the relationships between these factors and atherosclerosis. Japanese type 2 diabetic patients with insulin resistance had significantly higher concentrations of triglyceride, remnant-like particle cholesterol, subcutaneous and visceral abdominal fat areas, leptin, high sensitive C-reactive protein (hs-CRP), and soluble E-selectin and lower concentration of adiponectin when compared to those with normal insulin sensitivity. There were, however, no significant difference in tumor necrosis factor (TNF)-alpha and soluble TNF receptors between the two groups. Serum triglyceride was positively correlated to visceral abdominal fat area, while serum leptin was positively correlated with subcutaneous abdominal fat area. In contrast, serum adiponectin was negatively correlated to visceral abdominal fat area. High sensitive CRP was positively correlated to BMI, triglyceride, and leptin, but was negatively correlated to adiponectin. Tumor necrosis factor-alpha and soluble TNF receptors, however, were not associated with any of these factors. Thus, it may be hypothesized that Japanese type 2 diabetic patients are divided into two categories: one with normal insulin sensitivity and the other with insulin resistance. The former group has a low cardiovascular risk factor, whereas the latter one has a markedly increased cardiovascular disease risk factor. Furthermore, abdominal fat related insulin resistance seems to be associated with insulin resistance in Japanese type 2 diabetic patients. In this section, we would like to focus on the factors contributing to insulin resistance and discuss the association of these factors with atherosclerosis in Japanese type 2 diabetic patients.

Metabolic syndrome, insulin resistance, and atherosclerosis in Japanese type 2 diabetic patients

The aim of the present study was to investigate the relationships between metabolic syndrome and atherosclerosis in 57 Japanese type 2 diabetic patients. Metabolic syndrome was diagnosed based on the criteria raised by the Japan Internal Medicine Society. Insulin resistance was estimated by the insulin resistance index of homeostasis model assessment. Ultrasonographically measured carotid atherosclerosis, brachial-ankle pulse wave velocity (ba-PWV), and ankle brachial index (ABI) were used to assess the degree of atherosclerosis. Of 57 patients, 25 were diagnosed as having metabolic syndrome. The patients with metabolic syndrome had significantly higher levels of waist circumference, insulin, insulin resistance index of homeostasis model assessment, systolic and diastolic blood pressures, and serum triglycerides, and lower concentrations of adiponectin. However, there was no significant difference in age, sex, glycosylated hemoglobin (hemoglobin A1c), fasting glucose, leptin, and tumor necrosis factor system activities including tumor necrosis factor alpha between the 2 groups. Furthermore, no significant difference was observed in the degree of carotid atherosclerosis (intimal-medial thickness in plaque-free segments: 0.72+/-0.03 vs 0.72+/-0.02 mm, P=.435; carotid stenosis in plaque segments: 6.6%+/-3.0% vs 6.6%+/-1.7%, P=.497), ba-PWV (1676+/-56 vs 1654+/-44, P=.380), and ABI (1.16+/-0.01 vs 1.15+/-0.01, P=.245) between the 2 groups. From these results, it can be suggested that metabolic syndrome, an insulin-resistant state, is not associated with carotid atherosclerosis, ba-PWV, or ABI in Japanese type 2 diabetic patients.

Differences in coronary heart disease prevalence and risk factors in African and White patients with type 2 diabetes

Coronary heart disease (CHD) is rare in sub-Saharan Africans; there are few data in African diabetic populations. We therefore evaluated the prevalence of CHD and conventional risk factors in 744 consecutive African (A, n=448) and White European (W, n=296) subjects with type 2 diabetes. CHD was present in 4% of A and in 23% of W (p<0.001). Compared with W, the A groups had lower total cholesterol (TC) and triglyceride (TG) levels: men: TC-W, 5.76 (S.D., 1.36) and A, 4.98 (1.29)mmol/l; TG-W, 2.10 (IQR,1.40-3.00) and A, 1.60 (1.10-2.55)mmol/l; women: TC-W, 5.85 (1.31) and A, 5.20 (1.24); TG-2.00 (1.40-2.90) and A, 1.40 (1.00-2.03)mmol/l (p< or =0.0022 for each comparison). The A had significantly lower TG:HDL-C ratios (an index of insulin resistance) (p=0.004) and were less likely to have (estimated) small dense LDL-C particles (p< or =0.038). In subjects with established CHD traditional risk factors were similar in A and W. Regression analysis revealed that CHD associated in A with serum creatinine (p=0.0015) and TC (p=0.038) and with TG in W (p=0.0072). We conclude that the rarity of CHD in diabetic Africans can be explained by contributions of low TC levels and probably lesser insulin resistance and its consequences; renal disease may be an important additional risk factor.

High-density lipoprotein cholesterol and insulin resistance are independent and additive markers of left ventricular hypertrophy in essential hypertension

We examined whether plasma high-density lipoprotein-cholesterol (HDL-C) levels and glucose metabolism parameters are independent or additive predictors of left ventricular hypertrophy (LVH) in patients with untreated essential hypertension. The study group consisted of 41 Japanese patients with untreated essential hypertension and LVH (left ventricular mass index [LVMI] >125 g/m2; age 58+/-6 years, mean+/-SD), and the control group consisted of 39 age-matched patients with untreated essential hypertension without LVH (LVMI <or=125 g/m2; age 58+/-7 years). The following metabolic parameters were higher in the group with LVH: fasting plasma glucose (FPG) (p<0.01), fasting insulin concentration (F-IRI) (p<0.0001), and homeostasis model assessment (HOMA)-index (p<0.0001). Among the laboratory parameters investigated, plasma HDL-C levels were lower (p<0.0001), and triglyceride and uric acid levels were higher in the group with LVH (p<0.05 for both). The nighttime systolic and diastolic ambulatory blood pressure (ABP) (p<0.0001, p<0.01, respectively) and nighttime heart rate (p<0.01) were higher in patients with LVH. Multivariate logistic analysis identified HDL-C (odds ratio [OR]=0.92, 95% confidence interval [CI]=0.87-0.98, p<0.05), HOMA-index (OR=3.83, 95% CI=1.28-11.5, p<0.05) and nighttime systolic ambulatory blood pressure (ABP) (OR=1.06, 95% CI=1.00-1.13, p<0.05) as independent significant risk factors for LVH. Our findings suggest that HDL-C, HOMA-index and nighttime systolic ABP are independent predictors for the presence of LVH in Japanese patients with essential hypertension.

Role of growth hormone, insulin-like growth factor 1 and insulin-like growth factor-binding protein 3 in development of non-alcoholic fatty liver disease

BACKGROUND AND AIMS

Pituitary dysfunction including growth hormone (GH) deficiency may be associated with non-alcoholic fatty liver disease (NAFLD). Since the relationships among GH, IGF-1, IGFBP-3, and development of NAFLD without hypopituitarism are unclear, we examined the role of these hormones in the development of NAFLD based on clinical, laboratory and liver histology data.

PATIENTS AND METHODS

A total of 55 consecutive patients (20 males and 35 females) with NAFLD.

RESULTS

Aspartate amino transferase (AST), AST/ALT, platelet count and IGF-1, levels were significantly associated with differences in fibrosis, since these variables differed between stage 0-1 and stage 2-3 NAFLD. In multivariate analysis, platelet count (P = 0.0223, relative risk (RR), 5.899; 95% confidence interval (CI), 1.288-27.017), and IGF-1 (P = 0.0363, RR, 4.568; 95% CI, 1.101-18.945) showed significant associations with stage 2-3 NAFLD. Additionally, hyaluronic acid levels had a negative relationship with IGF-1 and the IGF-1/IGFBP-3 ratio. There was no relationship of fibrosis with GH level, but decreased GH (P = 0.0414, RR, 0.199; 95% CI, 0.042-0.989) was significantly associated with steatosis of stage 2-3. Low GH/IGF-1 and GH/IGFBP-3 ratios were found in advanced steatosis.

CONCLUSION

GH, IGF-1 and IGFBP-3 are associated with hepatic fibrosis and steatosis in NAFLD. Low levels of IGF-1 might be associated with fibrosis while low level of GH with hepatic steatosis.

Soluble tumor necrosis factor receptor 2 is independently associated with pulse wave velocity in nonobese Japanese patients with type 2 diabetes mellitus

The aim of the present study was to investigate the factors contributing to pulse wave velocity (PWV) in patients with type 2 diabetes mellitus. We focused on tumor necrosis factor (TNF) including soluble TNF receptors (sTNF-R1, sTNF-R2) in this study because TNF seems to be associated with the progression of atherosclerosis and because the relationships between PWV and TNF were not yet examined in type 2 diabetic patients. Univariate regression analyses showed that PWV was positively correlated with age (r=0.492, P<.001), diabetes duration (r=0.251, P=.021), systolic (r=.595, P<.001) and diastolic (r=0.248, P=.022) blood pressure, antihypertensive medication (r=0.268, P=.013), and the concentrations of sTNF-R1 (r=0.354, P=.001) and sTNF-R2 (r=0.415, P<.001). Although there was a positive correlation between TNF-alpha and sTNF-R1 (r=0.382, P<.001) or sTNF-R2 (r=0.394, P<.001), TNF-alpha was not associated with PWV. Other variables including gender were not associated with PWV. Multiple regression analyses showed that PWV was independently predicted by the level of age (F=15.1), systolic blood pressure (F=31.6), and sTNF-R2 (F=5.2), which explained 49.2% of the variability of PWV. From these results, it can be concluded that serum soluble TNF receptor is an important independent factor associated with aortic PWV in type 2 diabetic patients.

Effect of corosolic acid on postchallenge plasma glucose levels

Corosolic acid (CRA) is a substance extracted from Lagerstroemia speciosa L. and has been reported to have biological activities in in vitro and experimental animal studies. In this study, 31 subjects were orally administered 10mg CRA or a placebo, on different occasions, in a capsule 5min before the 75-g oral glucose tolerance test (OGTT) in a double-blind and cross-over design. Nineteen subjects had diabetes, seven had impaired glucose tolerance, one had impaired fasting glucose, and four had normal glucose tolerance according to the 1998 WHO criteria. There were no significant differences in plasma glucose levels before and 30min after the administration. CRA treatment subjects showed lower glucose levels from 60min until 120min and reached statistical significance at 90min. In this study, we have shown for the first time that CRA has a lowering effect on postchallenge plasma glucose levels in vivo in humans.

Hyperinsulinemia is associated with increased production rate of intestinal apolipoprotein B-48-containing lipoproteins in humans

OBJECTIVE

Whereas postprandial hyperlipidemia is a well-described feature of insulin-resistant states and type 2 diabetes, no previous studies have examined intestinal lipoprotein production rates (PRs) in relation to hyperinsulinemia or insulin resistance in humans.

METHODS AND RESULTS

Apolipoprotein B-48 (apoB-48)-containing lipoprotein metabolism was examined in the steady-state fed condition with a 15-hour primed constant infusion of [D3]-l-leucine in 14 nondiabetic men with a broad range of body mass index (BMI) and insulin sensitivity. To examine the relationship between indices of insulin resistance and intestinal lipoprotein PR data were analyzed in 2 ways: by correlation and by comparing apoB-48 PRs in those whose fasting plasma insulin concentrations were above or below the median for the 14 subjects studied (60 pmol/L). ApoB-48 PR was significantly higher in hyperinsulinemic, insulin-resistant subjects (1.73+/-0.39 versus 0.88+/-0.13 mg/kg per day; P<0.05) and correlated with fasting plasma insulin concentrations (r=0.558; P=0.038), despite great heterogeneity in apoB-48 kinetic parameters, particularly among the obese subjects. There was no significant difference in clearance of apoB-48 between the 2 groups, nor was there a significant correlation between apoB-48 fractional clearance rate and fasting insulin or homeostasis model assessment-insulin resistance.

CONCLUSIONS

These are the first human data to conclusively demonstrate that intestinal apoB-48-containing triglyceride-rich lipoprotein PR is increased in hyperinsulinemic, insulin-resistant humans. Intestinal lipoprotein particle overproduction is a newly described feature of insulin resistance in humans.

Interleukin 6, adiponectin, leptin, and insulin resistance in nonobese Japanese type 2 diabetic patients

The aim of the present study was to investigate the relationships between interleukin 6 (IL-6) and insulin resistance, serum leptin, serum adiponectin, or serum lipids including triglycerides in 98 nonobese Japanese type 2 diabetic patients. Insulin resistance was estimated by the insulin resistance index of homeostasis model assessment (HOMA-IR). Serum IL-6 concentration was negatively correlated to high-density lipoprotein cholesterol (r = -0.295, P = .004), but was not associated with HOMA-IR (r = 0.016, P = .871), body mass index (BMI) (r = 0.090, P = .375), systolic (r = 0.169, P = .116) and diastolic (r = -0.061, P = .570) blood pressures, leptin (r = 0.062, P = .544), and adiponectin (r = -0.020, P = .841) in these patients. In contrast, serum leptin level was positively correlated to HOMA-IR (r = 0.291, P = .004), BMI (r = 0.338, P < .001), and systolic blood pressure (r = 0.241, P = .025). Serum adiponectin level was negatively correlated to HOMA-IR (r = -0.288, P = .005), BMI (r = -0.308, P = .002), diastolic blood pressure (r = -0.269, P = .012), and triglycerides (r = -0.338, P < .001), and positively correlated to high-density lipoprotein cholesterol (r = 0.300, P = .003) in our patients. From these results, it can be suggested that fasting serum IL-6 is not a major factor responsible for the evolution of insulin resistance in nonobese Japanese type 2 diabetic patients.