Yoko Ichikawa

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.

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.

Effect of postprandial thermogenesis on the cutaneous vasodilatory response during exercise

To examine the effect of postprandial thermogenesis on the cutaneous vasodilatory response, 10 healthy male subjects exercised for 30 min on a cycle ergometer at 50% of peak oxygen uptake, with and without food intake. Mean skin temperature, mean body temperature (Tb), heart rate, oxygen uptake, carbon dioxide elimination, and respiratory quotient were all significantly higher at baseline in the session with food intake than in the session without food intake. To evaluate the cutaneous vasodilatory response, relative laser Doppler flowmetry values were plotted against esophageal temperature (Tes) and Tb. Regression analysis revealed that the [Formula: see text] threshold for cutaneous vasodilation tended to be higher with food intake than without it, but there were no significant differences in the sensitivity. To clarify the effect of postprandial thermogenesis on the threshold for cutaneous vasodilation, the between-session difference in the Tes threshold and the Tb threshold were plotted against the between-session difference in baseline Tes and baseline Tb, respectively. Linear regression analysis of the resultant plot showed significant positive linear relationships (Tes: r = 0.85, P < 0.01; Tb: r = 0.67, P < 0.05). These results suggest that postprandial thermogenesis increases baseline body temperature, which raises the body temperature threshold for cutaneous vasodilation during exercise.

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.

Practical application of flavonoid-poor menu meals to the study of the bioavailability of bilberry anthocyanins in human subjects

Practical application of flavonoid-poor menus was evaluated on the bioavailability of anthocyanins as model flavonoids. Detectable amounts of flavonoids were not found in plasma and urine collected from 13 participants, who took the menus. After ingesting bilberry anthocyanins (919 μmol), average plasma AUC0-6h, Cmax, Tmax values and urinary recovery were 386.0 nmol h/mL, 139.1 nM, 1.31 h and 0.21%, respectively.

Effect of food intake on the ventilatory response to increasing core temperature during exercise

Food intake increases metabolism and body temperature, which may in turn influence ventilatory responses. Our aim was to assess the effect of food intake on ventilatory sensitivity to rising core temperature during exercise. Nine healthy male subjects exercised on a cycle ergometer at 50% of peak oxygen uptake in sessions with and without prior food intake. Ventilatory sensitivity to rising core temperature was defined by the slopes of regression lines relating ventilatory parameters to core temperature. Mean skin temperature, mean body temperature (calculated from esophageal temperature and mean skin temperature), oxygen uptake, carbon dioxide elimination, minute ventilation, alveolar ventilation, and tidal volume (VT) were all significantly higher at baseline in sessions with food intake than without food intake. During exercise, esophageal temperature, mean skin temperature, mean body temperature, carbon dioxide elimination, and end-tidal CO2 pressure were all significantly higher in sessions with food intake than without it. By contrast, ventilatory parameters did not differ between sessions with and without food intake, with the exception of VT during the first 5 min of exercise. The ventilatory sensitivities to rising core temperature also did not differ, with the exception of an early transient effect on VT. Food intake increases body temperature before and during exercise. Other than during the first 5 min of exercise, food intake does not affect ventilatory parameters during exercise, despite elevation of both body temperature and metabolism. Thus, with the exception of an early transient effect on VT, ventilatory sensitivity to rising core temperature is not affected by food intake.