Sex differences in the association between level of childhood interleukin-6 and insulin resistance in adolescence

Serum and gene expression levels of CT-1, IL-6, and TNF-α after a lifestyle intervention in obese children

BACKGROUND

Inflammation related molecules such as tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), and cardiotrophin-1 (CT-1) are highly expressed in obese individuals and could partly explain some comorbidities associated to obesity. In obese children, lifestyle interventions are able to lower inflammation and reduce cardiovascular risk factors associated with obesity. The aim of the present work was to study changes in inflammation-related molecules serum and peripheral blood mononuclear cells (PBMC) transcript levels after a 10-week lifestyle intervention in obese children and asses their potential association with glucose metabolism.

METHODS

Twenty-three obese children (mean age 11.5 years; 48% males) underwent a 10-week lifestyle not controlled intervention trial. Anthropometric and biochemical measurements were analyzed. Transcript analysis for CT-1, IL-6, and TNF-α in PBMC were performed by RT-PCR. Serum cytokine levels were also measured at baseline and after 10-weeks.

RESULTS

Participants achieved a significant reduction in body adiposity (0.34 decrease in body mass index-standard deviation), total cholesterol, and glucose levels after 10-weeks. A Significant decrease in serum TNF-α and C reactive protein (CRP) were observed. CT-1 transcript levels were significantly reduced (P = .005) after lifestyle intervention, and these changes were significantly correlated with changes in serum CT-1 levels (r = 0.451; P = .031). In multiple regression analysis baseline CT-1 transcript levels were positively associated with final insulin (R² = 0.506; P = .035) and HOMA-IR values (R² = 0.473; P = .034).

CONCLUSIONS

We reported that serum CRP, TNF-α, as well as PBMC CT-1 transcript levels were reduced after lifestyle intervention in obese children. More studies are needed to clarify the role of inflammation-related molecules in glucose metabolism.

Effect of folic acid and metformin on insulin resistance and inflammatory factors of obese children and adolescents

Background:

Considering the increasing trend of obesity, especially in developing countries such as Iran, and the role of inflammatory factors and insulin resistance (IR) in the occurrence of obesity-related complications as well as the safety of some agents such as folic acid and metformin, this clinical trial was designed to investigate the effect of metformin and folic acid on inflammatory factors and IR among obese children.

Materials and Methods:

In this randomized, double-blind, controlled clinical trial study, sixty obese children aged 6–12 years were enrolled. Selected obese children were randomly allocated in two interventional (1 mg/daily folic acid or 1000 mg metformin for 8 weeks) groups. Biochemical measurements including homeostasis model assessment of IR (HOMA-IR), homocysteine (Hcy), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-8 (IL-8) were measured between and within the groups before and after trial.

Results:

In each group, thirty obese children were studied. The groups were age- and sex-matched. After folic acid and metformin administration, mean of Hcy, HOMA-IR, TNF-α, and IL-8 decreased significantly (P < 0.05). IL-6 decreased significantly after folic acid use (P < 0.05).

Conclusion:

The findings of this trial indicated that both metformin and folic acid could decrease IR and level of Hcy in obese children and adolescents. The effectiveness of metformin on IR was more significant than folic acid. Regarding the effectiveness of the two studied agents on inflammatory factors, it is suggested that the role of folic acid was superior to metformin. It is suggested that metformin is a proper agent for obese children with IR and folic acid is an appropriate supplement for obese children with increased inflammatory factors.

Whole-body and hepatic insulin resistance in obese children

Background

Insulin resistance may be assessed as whole body or hepatic.

Objective

To study factors associated with both types of insulin resistance.

Methods

Cross-sectional study of 182 obese children. Somatometric measurements were registered, and the following three adiposity indexes were compared: BMI, waist-to-height ratio and visceral adiposity. Whole-body insulin resistance was evaluated using HOMA-IR, with 2.5 as the cut-off point. Hepatic insulin resistance was considered for IGFBP-1 level quartiles 1 to 3 (<6.67 ng/ml). We determined metabolite and hormone levels and performed a liver ultrasound.

Results

The majority, 73.1%, of obese children had whole-body insulin resistance and hepatic insulin resistance, while 7% did not have either type. HOMA-IR was negatively associated with IGFBP-1 and positively associated with BMI, triglycerides, leptin and mother's BMI. Girls had increased HOMA-IR. IGFBP-1 was negatively associated with waist-to-height ratio, age, leptin, HOMA-IR and IGF-I. We did not find HOMA-IR or IGFBP-1 associated with fatty liver.

Conclusion

In school-aged children, BMI is the best metric to predict whole-body insulin resistance, and waist-to-height ratio is the best predictor of hepatic insulin resistance, indicating that central obesity is important for hepatic insulin resistance. The reciprocal negative association of IGFBP-1 and HOMA-IR may represent a strong interaction of the physiological processes of both whole-body and hepatic insulin resistance.

Effects of gender on sympathovagal imbalance, prehypertension status, and cardiovascular risks in first-degree relatives of type 2 diabetics

BACKGROUND

Although cardiovascular (CV) risks are reported in first-degree relatives (FDRs) of type 2 diabetics, effects of gender on sympathovagal imbalance (SVI) and CV risks in these subjects have not been investigated.

METHODS

Body mass index (BMI), blood pressure variability parameters including baroreflex sensitivity (BRS), spectral indices of heart rate variability, autonomic function tests, insulin resistance, lipid profile, inflammatory markers (interleukin 6, high-sensitivity C-reactive protein, tumor necrosis factor α) and oxidative stress (OS) marker were measured and analyzed in control group (without family history of diabetes; 65 women, 60 men) and study group (FDRs of type 2 diabetics; 52 women, 49 men) subjects.

RESULTS

BMI, heart rate, blood pressure, rate-pressure product, stroke volume, left-ventricular ejection time, cardiac output, total peripheral resistance, homeostatic model of insulin resistance, lipid profile, inflammatory and OS markers, and ratio of low-frequency to high-frequency power of heart rate variability (LF-HF ratio), a sensitive marker of SVI, were significantly increased, and BRS was significantly decreased in study group men compared with women. SVI was more intense in men and was due to concomitant sympathetic activation and vagal inhibition. There was no SVI in control subjects. Multiple regression analysis demonstrated independent contribution of BMI, homeostatic model of insulin resistance, atherogenic index, inflammatory and OS markers, and BRS to LF-HF ratio. Logistic regression analysis demonstrated significant prediction of prehypertension status and rate-pressure product (markers of CV risk) by LF-HF, which was more prominent in men.

CONCLUSIONS

SVI is more intense in male FDRs of type 2 diabetics, and SVI is associated with increased CV risk due to insulin resistance, dyslipidemia, inflammation, and oxidative stress in these subjects.