Yasumi Misaki

Plasma interleukin-1β concentrations are closely associated with fasting blood glucose levels in healthy and preclinical middle-aged nonoverweight and overweight Japanese men

Plasma interleukin (IL)-1β and IL-6 are markers that predict the risk of inflammation in diabetes. In the current study, we examined the relationship between fasting glucose and plasma inflammatory cytokines (IL-1β and IL-6) concentrations in healthy and preclinical middle-aged Japanese men (mean ± SD, 58.7 ± 7.8 years old) divided according to body mass index (<25 kg/m(2), nonoverweight group; ≥25 kg/m(2), overweight group). We conducted a cross-sectional study of 413 healthy and preclinical men aged 40 to 69 years who participated in health checkups in Japan. We measured their clinical parameters, lifestyle factors, and plasma IL-1β and IL-6 concentrations. Participants were classified according to their fasting blood glucose levels, and we compared their plasma cytokine levels. Plasma IL-1β and IL-6 levels in nonoverweight subjects were positively and strongly associated with fasting blood glucose and hemoglobin A(1c); in contrast, these cytokines were strongly associated with homeostasis model assessment of insulin resistance and fasting glucose in overweight subjects. Significant positive associations between plasma IL-1β and glucose concentrations were observed within the groups classified according to glucose concentrations, after adjustment for age and body mass index. The results of our current study show that plasma IL-1β levels are strongly associated with fasting blood glucose concentrations in healthy and preclinical nonoverweight and overweight Japanese men.

A higher rate of eating is associated with higher circulating interluekin-1β concentrations in Japanese men not being treated for metabolic diseases

OBJECTIVE In this study, we examined the relations between the rate of eating and circulating interleukin (IL)-1β and IL-6 levels in Japanese men not being treated for metabolic diseases. METHODS We conducted a cross-sectional study of 170 men 40 to 59 y old (mean ± standard deviation, 51.4 ± 5.7 y old) who participated in health checkups in Japan and were not being treated for metabolic diseases. We measured clinical serum parameters and plasma IL-1β and IL-6 concentrations and assessed by questionnaire lifestyle factors such as the dietary intake of food/nutrition and the rate of eating. Using multivariate linear regression analysis, we analyzed the relations between the rate of eating and IL-1β and IL-6 concentrations, clinical parameters, and lifestyle factors. RESULTS Significant Spearman correlation coefficients with the rate of eating were observed for IL-1β and IL-6 (0.250 and 0.195, respectively). The rate of eating was positively associated with IL-1β independently of IL-6, body mass index, homeostasis model assessment for insulin resistance, alcohol intake, energy intake, smoking status, and physical activity. CONCLUSIONS These results indicate that a higher rate of eating is positively and independently associated with circulating IL-1β concentrations in Japanese men not being treated for metabolic diseases.

The Combination of Genetic Variations in the PRDX3 Gene and Dietary Fat Intake Contribute to Obesity Risk

Oxidative stress is caused by an imbalance between the production of reactive oxygen species (ROS) and the antioxidant capacity of the cell. This imbalance and an excess of ROS induce tissue/cellular damage, which are implicated in chronic inflammation disorders such as obesity, insulin resistance, and metabolic syndromes. Peroxiredoxins (Prxs) are the most abundant and ancient cellular antioxidant proteins that help to control intracellular peroxide levels and ROS‐dependent signaling. Of the six mammalian isoforms, Prx III is specifically localized in mitochondria. In this study, we detected novel associations between genetic variations of the PRDX3 gene and BMI and obesity risk in the general Japanese population. In addition, these associations were observed only in the subjects with high dietary fat intake, but not in the subjects with low dietary fat intake. These findings indicate that the interaction between genetic variations in the PRDX3 gene and dietary fat intake is important for modulation of BMI and obesity risk.

Circulating interleukin-1β and interleukin-6 concentrations are closely associated with γ-glutamyltranspeptidase activity in middle-aged Japanese men without obvious cardiovascular diseases.

Interleukin (IL)-1β and IL-6 expressions are known to be induced by oxidant stress. In the present study, we examined the relationships between these interleukins and the activity of γ-glutamyltranspeptidase (γ-GTP), which was recently reported as a source of oxidant stress production, in the circulating blood of middle-aged Japanese men without obvious cardiovascular diseases. We conducted a cross-sectional study of 317 Japanese men without obvious cardiovascular diseases aged 40 to 69 years (mean ± SD, 58.6 ± 7.6 years) who participated in health checkups in Japan. We analyzed their clinical parameters in serum, lifestyle factors, and plasma IL-1β and IL-6 concentrations. We compared the relationships between these interleukin concentrations and the clinical parameters and lifestyle factors by Spearman correlation coefficients. Stepwise multiple linear regression analyses for interleukins based on the other parameters and γ-GTP, which were classified into 3 groups according to the concentrations, were performed. Interleukin-1β and IL-6 concentrations were closely associated with γ-GTP activity but less associated with alanine aminotransferase and aspartate aminotransferase activities by Spearman correlation coefficients. Stepwise multiple linear regression analyses showed that γ-GTP activity was the explanatory variable for elevated IL-1β and IL-6 concentrations. As natural logarithms, the IL-1β and IL-6 concentrations were estimated to be 1.734- and 1.157-fold higher, respectively, in subjects with high γ-GTP activity ranges than in subjects with a low γ-GTP activity range. The present results show that circulating IL-1β and IL-6 concentrations are strongly and independently associated with γ-GTP activity in middle-aged Japanese men without obvious cardiovascular diseases.

Plasma TNF-α Is Associated with Inflammation and Nutrition Status in Community-Dwelling Japanese Elderly

Inflammation has been suggested to play an important role in age-related chronic diseases and disability, and it is associated with nutritional status including obesity and malnutrition. While numerous studies have examined the validity of inflammatory markers in the population studies in Caucasian elderly people, very little information is available for the factors affecting inflammatory markers in Asian elderly people. Among inflammatory markers frequently used for the studies of aging, tumor necrosis factor α (TNF-α) is produced mainly by macrophages, and contributes to production of interleukin-6 (IL-6) and C-reactive protein (CRP), thus directing a chronic inflammatory process in the body. In the present study, we examined the associations between plasma TNF-α level and several factors related to nutrition status, including BMI, albumin, and energy intake in community-dwelling Japanese elderly. We conducted a cross-sectional study of 390 men and women aged 70-86 y (average 73.5 y), who participated in health check-ups. Associations between plasma TNF-α levels, other clinical parameters, and lifestyle factors were analyzed using Spearmans rank correlation coefficient analysis and multiple linear regression analysis. In elderly men, plasma TNF-α level was positively associated with age, white blood cell count, monocyte count, plasma CRP level, serum creatinine, ureic acid, and triacylglycerol levels, and negatively associated with albumin/globulin ratio, eGFR, and serum HDL-cholesterol level. In elderly women, plasma TNF-α level was positively associated with age, plasma CRP level, and serum triacylglycerol level, and negatively associated with serum albumin and HDL-cholesterol levels. The results of this study suggest that plasma TNF-α is associated with inflammation and insulin resistance in both Japanese elderly men and women, and a prominent association of TNF-α with malnutrition status was observed in elderly women.

Self-reported faster eating associated with higher ALT activity in middle-aged, apparently healthy Japanese women

OBJECTIVE Faster eating and elevated circulating activity of alanine aminotransferase (ALT), a marker for liver injury, are risk factors for the development of obesity and type 2 diabetes mellitus, and their complications. The aim of this study was to examine the association between self-reported eating rate and circulating ALT activity in apparently healthy middle-aged Japanese women. METHODS We conducted a cross-sectional study of 900 apparently healthy women ages 40 to 64 y (mean ± SD, 53.1 ± 7.1 y) who participated in health check-ups in Japan. We analyzed their clinical serum parameters and lifestyle factors, including self-reported eating rate. Associations between liver injury markers (ALT, γ-glutamyl transpeptidase [GTP], and aspartate aminotransferase [AST]), other clinical parameters and lifestyle factors were analyzed using Tukeys multiple range test following analysis of variance and analysis of covariance for three groups, divided by self-reported eating rates. The associations between self-reported faster eating and ALT activity and lifestyle factors were analyzed by multivariate logistic regression analyses. RESULTS ALT activity, but not γ-GTP or AST activities, was higher in participants who reported relatively fast/very fast eating than in those who reported medium eating after adjusting for age, alcohol intake, energy intake, smoking, and physical activity. The odds ratio of eating rate for ALT activity in T3 (18-128 U/L) compared with T1 (3-12 U/L) was 1.67 (P < 0.01), but the association disappeared after adjustment for body mass index (BMI). CONCLUSIONS ALT activity is positively associated with faster eating, but is dependent on BMI in middle-aged, apparently healthy Japanese women.