Effects of a single bout of aerobic exercise on short-term low-carbohydrate/high-fat intake-induced postprandial glucose metabolism during an oral glucose tolerance test

Objective

A single bout of exercise can improve acute postprandial glucose metabolism aggravated by short-term low-carbohydrate/high-fat diet (HFD). The purpose of this study was to investigate the effect of a single bout of aerobic exercise on short-term HFD-induced postprandial glucose and incretin metabolism during an oral glucose tolerance test (OGTT).

Materials/Methods

Eleven healthy young men (age [mean ± SE] 27 ± 1 years; body mass index, 22 ± 1 kg/m²) performed three, 3-day interventions in randomized order: (1) a normal diet (ND: ~ 22% fat), (2) an HFD (~ 69% fat) and (3) an HFD with a single bout of aerobic exercise (HFDEx). The exercise (50% peak oxygen consumption; ~ 200 kcal) was performed on the third day in HFDEx. An OGTT was performed after each 3-day dietary intervention.

Results

The incremental area under the curve (iAUC) of plasma glucose levels during the OGTT was significantly higher in the HFD and HFDEx trials than in the ND trial (P = 0.001). In addition, the iAUC of glucagon-like peptide-1 (GLP-1) level was significantly higher in the HFD trial than in the ND and HFDEx trials (P = 0.04). The first-phase insulin secretion indexes were significantly lower in the HFD (P = 0.01 and 0.002) and HFDEx trials (P = 0.05 and 0.008) than in the ND trial.

Conclusion

A single bout of aerobic exercise did not improve the short-term HFD-induced aggravation of postprandial glucose and insulin metabolism during the OGTT. However, it did normalize the increased postprandial GLP-1 level induced by HFD.     

Serum levels of soluble receptor for advanced glycation end-products and metabolic syndrome: The Northern Manhattan Study

Objective

Recent studies have shown a strong link between serum soluble receptor for advanced glycation end-products (sRAGE) levels and cardiovascular risk factors and disease. What is less clear is the relationship between metabolic risk factors and sRAGE levels. Here, we tested the hypothesis that lower sRAGE levels may be associated with the metabolic syndrome (MetS) in an urban multi ethnic population.

Materials/methods

From the Northern Manhattan Study (NOMAS), we included 1101 stroke-free participants (mean age: 71 ± 9 years, 60% women, 64% Hispanic, 18% black, 16% white). Serum sRAGE was measured by ELISA. Quantile regression analysis was performed to evaluate the association between sRAGE and MetS components and MetS, after adjusting for sociodemographics, smoking status and kidney function.

Results

The median (interquartile) sRAGE was 899 pg/ml (647–1248 pg/ml), 42% had metabolic syndrome. The prevalence of unfavorable metabolic factors was 50% for waist circumference (WC), 81% for blood pressure, 39% for fasting glucose, 35% for reduced high density lipoproteins (HDL), and 23% for triglycerides. After adjustment, the median sRAGE levels were at least 120 pg/ml lower in those who had elevated WC (p < 0.0001), blood pressure (p = 0.0014), and fasting glucose (p < 0.0001), and those who had 2 or more unfavorable metabolic factors. No relationship was seen between sRAGE levels and elevated triglycerides or reduced HDL levels. Interaction and stratified analyses revealed that the association of sRAGE with MetS was more prominent in Hispanics compared to whites, and displaying no association with components of MetS in blacks.

Conclusions

sRAGE levels were mainly associated with MetS factors related to obesity, diabetes and hypertension, and displayed variation with ethnicity in a multi-ethnic population. Further studies of sRAGE, MetS and their relationship to cardiovascular disease are warranted.     

The Effect of α-Cyclodextrin on postprandial lipid and glycemic responses to a fat-containing meal

Objective

α-Cyclodextrin (α-CD), a soluble dietary fiber derived from corn, marketed under the trade name FBCx®, has the potential to help individuals manage their weight and improve their lipid profiles. Initial studies in healthy overweight and/or obese diabetic individuals found that, in those consuming a normal to high fat diet over a 4 or 12 week period, α-CD use was associated with weight loss or maintenance and a reduction in triglyceride (TG) and cholesterol levels in hyperlipidemic individuals. Furthermore, α-CD use was associated with the positive effects of increasing insulin and leptin sensitivities. To date, the immediate post-prandial glucose and lipid responses to a fat-containing meal have not been reported.

Materials/Method

This double blinded placebo controlled cross-over trial examined the effect of 2 g of α-CD taken immediately following consumption of a commercially prepared high-fat breakfast meal on the acute postprandial responses in healthy adults.

Results

The coincidental consumption of α-CD with a fat-containing meal was associated with a significant reduction in postprandial TG responses over time when compared to placebo. When incremental area under the curve was calculated, the area under the curve associated with α-CD consumption was significantly smaller than the Placebo area (0.30 ± 1.07 mmol/L/3 h vs. 0.98 ± 0.88 mmol/L/3 h, p < 0.05). There were no significant changes in glucose or cholesterol levels.

Conclusion

α-Cyclodextrin was shown to significantly lower acute postprandial blood triglyceride levels.     

Relationship between whole-body macronutrient oxidative partitioning and pancreatic insulin secretion/β-cell function in non-diabetic humans

Background

Glucose-stimulated insulin secretion correlates inversely with the degree of whole-body insulin sensitivity suggesting a crosstalk between peripheral organs and pancreas. Such sensing mechanism could be mediated by changes in glucose flux (uptake, oxidation or storage) in peripheral tissues that may drive insulin secretion.

Aim

To relate whole-body non-protein respiratory quotient (npRQ), an index of macronutrient oxidative partitioning, with insulin secretion and β-cell function in non-diabetic individuals.

Methods

Macronutrient oxidation was measured after an overnight fast and for 4 h after a 75-g oral glucose tolerance test (OGTT) in 30 participants (15/15 males/females; 35 ± 12 y; 27 ± 4 kg/m²). Furthermore, npRQ was assessed for 24 h in a metabolic chamber. Insulin secretion was estimated by deconvolution of serum C-peptide concentration (fasting and 4-h OGTT) and from 24-h urinary C-peptide excretion corrected for energy intake (metabolic chamber). β-Cell function parameters were obtained by mathematical modeling, while insulin sensitivity was determined by a euglycemic–hyperinsulinemic clamp (120 mU · m^− 2 · min^− 1).

Results

Insulin secretion (from 24-h urinary C-peptide) correlated inversely with 24-h npRQ (r = − 0.61; p = 0.001), even after controlling for insulin sensitivity, energy balance, age and body mass index (r = − 0.52; p = 0.01). In turn, insulin secretion (from serum C-peptide) was not associated with fasting or OGTT npRQ. However, fasting npRQ was positively correlated with rate sensitivity (r = 0.40; p < 0.05) and marginally with glucose sensitivity (r = 0.34; p = 0.08).

Conclusion

Macronutrient oxidative partitioning, specifically glucose oxidation, might play a role on the regulation of insulin secretion. Further studies should aim at identifying the signals linking these processes.     

Greater impairment of postprandial triacylglycerol than glucose response in metabolic syndrome subjects with fasting hyperglycaemia

Objective

Studies have started to question whether a specific component or combinations of metabolic syndrome (MetS) components may be more important in relation to cardiovascular disease risk. Our aim was to examine the impact of the presence of raised fasting glucose as a MetS component on postprandial lipaemia.

Methods

Men classified with the MetS underwent a sequential test meal investigation, in which blood samples were taken at regular intervals after a test breakfast (t = 0 min) and lunch (t = 330 min). Lipids, glucose and insulin were measured in the fasting and postprandial samples.

Results

MetS subjects with 3 or 4 components were subdivided into those without (n = 34) and with (n = 23) fasting hyperglycaemia (≥ 5.6 mmol/l), irrespective of the combination of components. Fasting lipids and insulin were similar in the two groups, with glucose significantly higher in the men with glucose as a MetS component (P < 0.001). Following the test meals, there were higher maximum concentration (maxC), area under the curve (AUC) and incremental AUC (P ≤ 0.016) for the postprandial triacylglycerol (TAG) response in men with fasting hyperglycaemia. Greater glucose AUC (P < 0.001) and insulin maxC (P = 0.010) were also observed in these individuals after the test meals. Multiple regression analysis revealed fasting glucose to be an important predictor of the postprandial TAG and glucose response.

Conclusion

Our data analysis has revealed a greater impairment of postprandial TAG than glucose response in MetS subjects with raised fasting glucose. The worsening of postprandial lipaemic control may contribute to the greater CVD risk reported in individuals with MetS component combinations which include hyperglycaemia.     

Acute changes in lipoprotein subclasses during exercise

Objective

Lipids are important substrates for oxidation in the basal fasting state and during exercise. Studies have demonstrated beneficial changes in lipoprotein subclass composition the day after an exercise bout. However, the acute effect of exercise on TG concentration and lipoprotein subclass composition remains unclear.

Materials/Methods

Sixteen lean, healthy individuals (8 men and 8 women) were recruited (age 20–30 years, BMI < 25 kg/m²). The subjects were studied during basal fasting conditions as well as during and after 90 min of cycling at 50% of VO₂peak. Lipoprotein subclass composition was measured with ¹H NMR spectroscopy.

Results

During exercise, LDL and HDL particle concentration increased significantly (p < 0.05) despite lower total TG concentration. In addition, exercise resulted in a shift towards smaller VLDL particles in men (p < 0.05), but VLDL–TG concentration was unaltered.

Conclusions

Acute exercise induces beneficial changes in lipoprotein subclass composition. These changes are similar to the effects of exercise training.     

Elevated plasma fractalkine levels are associated with higher levels of IL-6, Apo-B,LDL-C and insulin,but not with body composition in a large female twin sample

Objective

Plasma fractalkine (FRACT) is involved in the development of numerous inflammatory conditions including atherosclerosis. It is associated with type 2 diabetes mellitus and adipose inflammation. However, whether FRACT is associated with major risk factors for cardiovascular disease, in particular obesity, metabolic syndrome and blood lipids, is virtually unknown.

Methods

The study included a large community-based sample of 3306 middle-aged women drawn from the general UK population. Blood samples were analyzed for circulating levels of FRACT, leptin, insulin, glucose, LDL-C, HDL-C, Apo-A, ApoB and IL-6. Obesity was assessed by fat body mass (FBM) using dual-energy x-ray absorptiometry and by body mass index (BMI).

Results

We found no association between FRACT and body composition, in particular adiposity. Obese and non obese subjects with metabolic syndrome tended to have higher levels of FRACT compared with non-obese subjects without metabolic syndrome but this did not reach statistical significance. Most importantly we report significant correlations between FRACT and circulating IL-6, Apo-B, LDL-C and insulin. The associations with IL-6 and Apo-B were particularly significant (P-value < 0.001), and survived correction for multiple testing and adjustment for age and other covariates.

Conclusion

Higher FRACT levels correlated with elevated levels of IL-6, Apo-B, LDL-C and insulin, all known risk factors for several clinical related diseases suggesting a potential role of FRACT in inflammation and tissue injury. Variations of FRACT levels are not influenced by body composition and are not correlated with leptin indicating that fat mass alone is not responsible for elevation of FRACT seen in obese individuals.     

Relative utility of 1-h Oral Glucose Tolerance Test as a measure of abnormal glucose homeostasis

Background and aims

Impaired glucose tolerance based on 2-h glucose levels is more predictive of future cardiovascular disease and more sensitive in detecting earlier diabetes compared to impaired fasting glucose. However, the 1-h OGTT may be even more sensitive than the 2-h. We assessed the relative value of 1-h OGTT by exploring its relationship with adiposity and other measures of glucose homeostasis.

Methods and results

Ninety four overweight/obese individuals free of diabetes and major cardiovascular conditions were included in the analyses. We adjusted for age, gender, smoking status and physical activity. One-h OGTT showed similar partial correlations with fasting glucose and 2-h OGTT (r = 0.60 and 0.64 respectively). Fasting glucose, fasting insulin and HOMA correlated better with 1-h OGTT (r = 0.60, 0.47 and 0.52) than with 2-h OGTT (r = 0.50, 0.41, and 0.45). BMI and waist circumference also showed stronger correlation with 1-h (r = 0.31, 0.29), compared to 2-h OGTT (r = 0.16, 0.16) or fasting glucose (r = 0.23, 0.22). Metabolic syndrome was associated similarly with 1-h and 2-h OGTT.

Conclusions

The 1-h OGTT correlates well with both fasting glucose and 2-h OGTT and shows similar or higher associations with obesity measures. The 1-h OGTT has potential utility in epidemiologic studies.     

The effects of improved metabolic risk factors on bone turnover markers after 12 weeks of simvastatin treatment with or without exercise

Objective

Emerging evidence supports an association between metabolic risk factors and bone turnover. Statins and exercise independently improve metabolic risk factors; however whether improvements in metabolic risk factor affects bone turnover is unknown. The purpose of the present study was to: 1) evaluate the relationship between metabolic risk factors and bone turnover; and 2) determine if improvements in metabolic risk factors after 12 weeks of statin treatment, exercise or the combination affect bone turnover.

Methods

Fifty participants with ≥ 2 metabolic syndrome defining characteristics were randomly assigned to one of three groups: statin (STAT: simvastatin, 40 mg/day), exercise (EX: brisk walking and/or slow jogging, 45 minutes/day, 5 days/week), or the combination (STAT + EX). Body composition and whole body bone mineral density were measured with dual energy X-ray absorptiometry. Serum markers of bone formation (bone specific alkaline phosphatase, BAP; osteocalcin, OC), resorption (C-terminal peptide of type I collagen, CTX) and metabolic risk factors were determined. Two-factor (time, group) repeated-measures ANCOVA was used to examine changes of metabolic risk factors and bone turnover. General linear models were used to determine the effect of pre-treatment metabolic risk factors on post-treatment bone turnover marker outcomes.

Results

Participants with ≥ 4 metabolic syndrome defining characteristics had lower pre-treatment OC than those with 3 or fewer. OC was negatively correlated with glucose, and CTX was positively correlated with cholesterol. STAT or STAT + EX lowered total and LDL cholesterol. The OC to CTX ratio decreased in all groups with no other significant changes in bone turnover. Higher pre-treatment insulin or body fat predicted a greater CTX reduction and a greater BAP/CTX increase.

Conclusion

Metabolic risk factors were negatively associated with bone turnover markers. Short-term statin treatment with or without exercise lowered cholesterol and all treatments had a small effect on bone turnover.     

A short message service (SMS) intervention to prevent diabetes in Chinese professional drivers with pre-diabetes: A pilot single-blinded randomized controlled trial

Aim

To determine the efficacy of delivering short-message service (SMS) to provide diabetes-related information in reducing the risk of developing diabetes in Chinese professional drivers with pre-diabetes.

Methods

A pilot single-blinded randomized controlled trial was conducted in Hong Kong between 05/2009 and 04/2012. Professional drivers with impaired glucose tolerance (IGT) were randomly allocated to either a SMS group receiving messages comprising knowledge and lifestyle modification on diabetes or to a control group with usual care. Primary outcomes were the incidence rate of diabetes mellitus over 12 and 24 months period.

Results

Fifty-four, out of 104 professional drivers recruited, were randomly allocated to intervention group. Fewer subjects developed diabetes at 12 months in intervention group (5.56%) compared to control group (16.00%). Relative risk (RR) of diabetes onset was 0.35 (95%CI: 0.10–1.24) and the number needed to treat (NNT) for preventing one diabetes was 9.57. At 24 months, RR increased to 0.62 (95%CI: 0.24–1.61) with a NNT of 10.58. Logistic regression showed a significant odds ratio of 0.04 (P = 0.021) for intervention group compared to control group at 12-month follow-up for completers and a non-significant odds ratio of 0.34 (P = 0.303) at 24-month follow-up.

Conclusions

The SMS program proved to have potential to reduce the risk of developing diabetes at 12 months but additional measures should be integrated to prevent or delay disease progression.     

Prevalence and associated metabolic factors of fatty liver disease in the elderly

Objective

The aim of this study was to investigate the metabolic risk factors for fatty liver disease in the elderly, and determine the prevalence of fatty liver disease in the elderly in Wuhan, central China.

Methods

The study was a case–control study based on all 4226 adults above 60 years of age from a cohort investigated in 2010–11 at the medical examination center of Zhongnan hospital, using 3145 randomly selected adults under 60 years of age from the same cohort as controls. Fatty liver disease (FLD) was identified with ultrasound imaging. The risk factors measured were body mass index (BMI), and plasma concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), low density lipoprotein (LDL) and serum uric acid (SUA). The probability of steatohepatitis with advanced fibrosis was predicted using a score based on BMI, age, ALT, and TG (BAAT),and using AST/ALT ratio (AAR).

Results

FLD was higher in the elderly (26.7%) than in the non-elderly (22.8%) and similar in the elderly between men and women (26.6% vs 27.0%, p > 0.05). BMI, TC, TG, LDL, SUA, AST and ALT were all significantly higher in FLD, whereas the level of HDL was markedly lower. Multiple regression analyses showed that obesity, high TC, TG, SUA, low HDL, and elevated ALT, AAR < 1 were closely related to the elderly FLD, while male sex, obesity, high TC, TG, low HDL, elevated ALT, AST and AAR < 1 were closely related to the non-elderly FLD. The prevalence of steatohepatitis with advanced fibrosis estimated as BAAT index ≥ 3 was 2.4% in all subjects, and was higher in the elderly FLD patients than in the non-elderly FLD patients.

Conclusion

The prevalence of FLD is higher in the elderly, and is broadly related to the same metabolic risk factors as in the non-elderly. However, female-sex is no longer protective with increasing age, and the prevalence of steatohepatitis with advanced fibrosis is estimated to be considerably higher in the elderly FLD patients than in the non-elderly FLD controls.     

Obesity with and without metabolic syndrome: Do vitamin D and thyroid autoimmunity have a role?

Aims

To investigate serum levels of thyroid stimulating hormone (TSH), anti-thyroid peroxidase antibody (TPO), and 25(OH)D in the presence or absence of metabolic syndrome in an obese population.

Methods

Data from a prospectively generated “Obesity Polyclinic” database that includes socio-demographic characteristics, anthropometric, and laboratory measurements of obese subjects were retrospectively analyzed. Subjects with body-mass index (BMI) ≥30 kg/m² were eligible. After detailed analysis and exclusion of unavailable cases, subjects diagnosed with and without metabolic syndrome were compared for TSH, anti-TPO, and 25(OH)D.

Results

Of the study participants (n = 548; men/women, 64/484), 277 were diagnosed with metabolic syndrome [Met-S (+)]. Met-S (+) patients had a higher mean BMI (36.4 vs. 32.3 kg/m², p < .001) and percentage body fat (PBF) (39.2 vs. 35.3%, p < .001), but similar TSH (2.1 vs. 2.2 mIU/mL, p = .759), anti-TPO (12 vs. 13 IU/mL, p = .483), 25(OH)D (13.2 vs. 12.6 ng/mL, p = .409), and calcium–phosphorus product (28.7 vs. 29.5 mg/dL, p = 0.275), compared to Met-S (−) subjects. When serum TSH, anti-TPO, and 25(OH)D levels were analyzed according to tertiles for comparisons of fasting plasma glucose, triglycerides, high-density lipoprotein cholesterol, BMI, and PBF, only 25(OH)D levels were negatively correlated with BMI and PBF.

Conclusions

Although decreased 25(OH)D levels were related to the degree of obesity in obese subjects, serum 25(OH)D levels per se did not seem to be associated with metabolic syndrome. The prevalence of thyroid autoimmunity and hypothyroidism were high in this obese sample; however, neither serum TSH nor anti-TPO levels correlated with metabolic syndrome. Our findings did not support the hypothesis that thyroid autoimmunity and/or vitamin D status have a role in the development of metabolic disturbances in the obese population.     

Prolonged sitting and markers of cardiometabolic disease risk in children and youth: A randomized crossover study

Objective

Recent evidence suggests that short bouts of uninterrupted sedentary behavior reduce insulin sensitivity and glucose tolerance while increasing triglyceride levels in both healthy and overweight/obese adults. To date no study has examined the acute impact of uninterrupted sitting in children and youth. The objective of the present study was to determine whether 8 h of uninterrupted sitting increases markers of cardiometabolic disease risk in healthy children and youth, in comparison to 8 h of sitting interrupted by light intensity walk breaks or structured physical activity.

Materials/Methods

11 healthy males and 8 healthy females between the ages of 10 and 14 years experienced 3 conditions in random order: (1) 8 h of uninterrupted sitting (Sedentary); (2) 8 h of sitting interrupted with a 2-min light-intensity walk break every 20 min (Breaks); and (3) 8 h of sitting interrupted with a 2-min light-intensity walk break every 20 min as well as 2 × 20 min of moderate-intensity physical activity (Breaks + Physical Activity). Insulin, glucose, triglyceride, HDL and LDL cholesterol area under the curve were calculated for each condition.

Results

We observed no significant differences in the area under the curve for any marker of cardiometabolic disease risk across the 3 study conditions (all p > 0.09).

Conclusions

These results suggest that in comparison to interrupted sitting or structured physical activity, a single bout of 8 h of uninterrupted sitting does not result in measurable changes in circulating levels of insulin, glucose, or lipids in healthy children and youth.     

Bariatric surgery in severely obese adolescents improves major comorbidities including hyperuricemia

Objective

Serum uric acid (sUA) is believed to contribute to the pathogenesis of metabolic comorbidities like hypertension, insulin-resistance (IR) and endothelial dysfunction (EDF) in obese children. The present pilot study investigated the association between sUA concentrations and loss of body weight following laparoscopic sleeve gastrectomy (LSG) or laparoscopic Roux-en-Y-gastric bypass (RYGB) in severely obese adolescents.

Materials/Methods

10 severely obese adolescents underwent either LSG (n = 5) or RYGB (n = 5). 17 normal weight, healthy, age- and gender-matched adolescents served as a normal weight peer group (NWPG). Pre- and 12 months postoperatively, sUA and relevant metabolic parameters (glucose homeostasis, transaminases, lipids) were compared.

Results

Preoperatively, sUA was significantly elevated in patients with severe obesity compared to NWPG. Twelve months after LSG and RYGB, a significant decrease in sUA, BMI, CVD risk factors, hepatic transaminases, and HOMA-IR was observed. Reduction in SDS-BMI significantly correlated with changes in sUA.

Conclusions

sUA levels and metabolic comorbidities improved following bariatric surgery in severely obese adolescents. The impact of changes in sUA on long-term clinical complications of childhood obesity deserves further study.     

Emerging parameters of the insulin and glucose response on the oral glucose tolerance test: Reproducibility and implications for glucose homeostasis in individuals with and without diabetes

Aims

Recent studies have suggested that novel parameters of the insulin and glucose response on the oral glucose tolerance test (OGTT) can provide metabolic insight beyond glucose tolerance, but have not evaluated their reproducibility. Thus, our aim was to evaluate the reproducibility of these parameters and, if confirmed, characterize their clinical/pathophysiologic relevance in healthy and diabetic individuals.

Methods

Thirty healthy adults each underwent 3 replicate OGTTs, enabling assessment of the reproducibility of the following 5 parameters: time to insulin peak, shape of the glucose curve, glucose nadir below baseline, 1-h post-challenge glucose, and time to glucose peak. The only reproducible parameter was then further evaluated in 63 patients with early type 2 diabetes (T2DM) before and after 4-weeks of intensive insulin therapy (IIT) designed to improve beta-cell function (measured by Insulin Secretion-Sensitivity-Index-2 (ISSI-2)).

Results

Of the five parameters, only time to glucose peak displayed reliable reproducibility on replicate testing (κ = 0.76). Over 80% of controls had their glucose peak at 30-min post-load, whereas all but one of the diabetic patients had their peak at 60-min or later. ISSI-2 was lower in T2DM patients with peak at ≥90-min than in those with peak at ≤60-min (P = 0.012). In patients in whom IIT improved beta-cell function by ≥20% from baseline, 39.1% had glucose peak on the post-therapy OGTT shift to an earlier timepoint, as compared to 15.4% with similar shift in those without such improvement(P = 0.03).

Conclusion

Time to glucose peak is a reproducible characteristic on the OGTT and associated with beta-cell function in early T2DM.     

Effects of exercise on C-reactive protein,inflammatory cytokine and adipokine in patients with type 2 diabetes: A meta-analysis of randomized controlled trials

Objective

C-reactive protein (CRP), inflammatory cytokines, and adipokines contribute to atherosclerosis, insulin resistance, and development of late-onset complication in patients with type 2 diabetes. We performed a systematic review to assess effects of exercise interventions on inflammatory markers/cytokines and adipokines.

Materials/Methods

We searched electronic databases (MEDLINE, EMBASE, and Cochrane Controlled Trials Registry) and reference lists in relevant papers for articles published in 1966–2013. We selected studies that evaluated the effects of exercise intervention on inflammatory markers/cytokines and adipokines in adult patients with type 2 diabetes. Weighted mean differences of exercise on outcomes were derived using fixed or random effect models; factors influencing heterogeneity were identified using meta-regression analysis.

Results

Fourteen randomized controlled trials (824 patients) were included in our meta-analysis. Exercise was associated with a significant in CRP = − 0.66 mg/l (95% CI, − 1.09 to − 0.23 mg/l; − 14% from baseline) and interleukin-6 (IL-6) = − 0.88 pg/ml (95% CI, − 1.44 to − 0.32 pg/ml; − 18% from baseline) but did not alter adiponectin or resistin levels; aerobic exercise program was associated with a significant change in leptin = − 3.72 ng/ml (95% CI, − 6.26 to − 1.18 ng/ml; − 24% from baseline). For IL-6, exercise was more effective in those with a longer duration in the program and larger number of sessions during study (p = 0.001).

Conclusions

Exercise decreases inflammatory cytokine (CRP and IL-6) in patients with type 2 diabetes. Exercise could be a therapeutic option for improving abnormalities in inflammation levels in patients with diabetes.     

Irisin in patients with nonalcoholic fatty liver disease

Objective

Irisin is a recently discovered myokine proposed to increase thermogenesis-related energy expenditure and improve metabolism. We aimed to comparatively evaluate serum irisin levels in patients with biopsy-proven nonalcoholic fatty liver disease (NAFLD) vs. controls and study their association with disease severity.

Methods

Fifteen and 16 consecutively enrolled patients with biopsy-proven nonalcoholic simple steatosis (NAFL) and steatohepatitis (NASH), respectively, and 24 lean and 28 obese controls without NAFLD were recruited. Irisin, established adipokines and biochemical tests were measured.

Results

Serum irisin levels were statistically different in obese controls (33.7 ± 2.7 ng/mL; p < 0.001) and patients with NAFL (30.5 ± 1.5 ng/mL; p < 0.001) and NASH (35.8 ± 1.9 ng/mL; p = 0.001) compared with lean controls (47.7 ± 2.0 ng/mL), but were similar among patients with NAFL, NASH and obese controls. This difference remained significant after adjustment for body mass index (or waist circumference), gender, age, insulin resistance (assessed by HOMA-IR or QUICKI), exercise and time since blood collection. Serum leptin and adiponectin, but not irisin, levels were independently from BMI correlated with insulin resistance and cardiometabolic factors. Serum irisin tended to be higher in patients with (36.7 ± 2.4 ng/mL) than without (30.8 ± 1.2 ng/mL; p = 0.02) portal inflammation and independently associated with the latter; these data need to be confirmed by future studies.

Conclusions

Serum irisin levels differ between lean controls and obese controls or NAFLD patients. Despite similar circulating irisin levels between NAFL and NASH groups, irisin may be independently and positively associated with the presence of portal inflammation. Future clinical and mechanistic studies are needed to confirm and extend these data.     

Higher serum bilirubin level as a protective factor for the development of diabetes in healthy Korean men: A 4 year retrospective longitudinal study

Objective

Bilirubin, a natural product of heme catabolism by heme oxygenase, one of key antioxidant enzymes, has been recognized as a substance with potent antioxidant and cytoprotective properties. Several studies have shown a significant negative relationship between serum bilirubin levels and the risk of metabolic disorders, including type 2 diabetes. However, longitudinal studies investigating the association of elevated serum bilirubin levels and type 2 diabetes are lacking. In the present study, we aimed to investigate the longitudinal effects of baseline serum bilirubin concentrations on the development of type 2 diabetes in healthy Korean men.

Materials and Methods

This 4 year retrospective longitudinal observational study was conducted at the Asan Medical Center, Seoul, Republic of Korea. The study population consisted of 5960 men without type 2 diabetes who underwent routine health examinations in 2007 (baseline) and 2011 (follow-up). Baseline serum bilirubin concentrations were determined by the vanadate oxidation method.

Results

During a 4 year period, 409 incident cases of diabetes (6.9 %) were identified. Incident type 2 diabetes decreased across the baseline bilirubin quartile categories (P for trend < 0.001). In multivariable-adjusted model, the relative risk (RR) for the development of type 2 diabetes was significantly lower in the highest (i.e., 1.30–2.00 mg/dl) than in the lowest bilirubin quartile category (i.e., ≤ 0.90 mg/dl), even after adjustment for confounding variables (RR = 0.69, 95% confidence interval 0.48–0.99, P for trend = 0.041).

Conclusions

The results indicate that serum total bilirubin level may provide additional information for predicting future development of type 2 diabetes in healthy subjects.     

Follistatin and activins in polycystic ovary syndrome: Relationship to metabolic and hormonal markers

Objective

Polycystic ovary syndrome (PCOS) is common and has reproductive and metabolic manifestations. Activin A and follistatin levels remain controversial and activin B levels are unstudied in PCOS. The aim of this study was to evaluate activin A, activin B and follistatin levels and to examine their associations with metabolic status in overweight and obese women with and without PCOS.

Materials and methods

Cross-sectional study assessing overweight and obese, premenopausal women with PCOS (n = 51, n = 26 National Institutes of Health (NIH) and n = 25 non-NIH) and without PCOS (n = 25 controls). Outcomes included activin A, activin B, follistatin and activin A/follistatin ratio and the association of the activins and follistatin with metabolic variables.

Results

Activin A, activin B and activin A/follistatin ratio were not significantly different and follistatin was elevated for PCOS versus controls (P = 0.01) independent of age or BMI. Follistatin levels were significantly different across the PCOS phenotypes (p = 0.05), however this was a non-significant trend (after correction for age and BMI) for women with NIH PCOS or non-NIH PCOS to have elevated levels in comparison to controls. Activin A was most strongly predicted by low density lipoprotein/high density lipoprotein (r² = 0.192, p < 0.001), follistatin by triglycerides and highly sensitive C-reactive protein (r² = 0.340, p < 0.001) and the activin A/follistatin ratio by insulin area under the curve and mean arterial pressure (r² = 0.289, p < 0.001).

Conclusions

Follistatin is elevated and activins A and B are not different between PCOS and controls. Follistatin and activin A are related to metabolic parameters in women with and without PCOS. Follistatin may potentially act as a marker of or be involved in the pathophysiology of both reproductive and metabolic features of PCOS.     

Circulating irisin,omentin-1, and lipoprotein subparticles in adults at higher cardiovascular risk

Objective

Muscle and fat are now recognized as metabolism-regulating endocrine organs. However, muscle and adipocyte-derived novel cytokines such as irisin and omentin-1 remain understudied in relation to metabolic biomarkers that are associated with cardiovascular risk.

Subjects and methods

Thirty-nine subjects with mean (± SD) BMI of 29.2 ± 5.4 kg/m² and either diabetes or two other cardiovascular risk factors were enrolled in a 6-month randomized trial of low-dose ethanol. We examined cross-sectional data at baseline, 3-month, and 6-month visits to assess (1) within-person stability of novel cytokines (irisin, omentin-1, visfatin, resistin, and soluble tumor necrosis factor receptor II) and (2) their associations with metabolic parameters, particularly lipoprotein subparticle profile.

Results

Repeated measures of irisin and omentin-1 were highly correlated, with intra-class correlations of 0.84 (95% CI: 0.74, 0.91; P < 0.001) and 0.81 (0.70, 0.89; P < 0.001), respectively. Irisin was negatively correlated with omentin-1 (7.4% irisin decrease per a 1-SD increment in omentin-1; 95% CI: 0.5%, 13.9%; P = 0.04). In models adjusted for age, sex, and race, irisin was negatively associated with HDL cholesterol (7.3% decrease per a 10 mg/dL increment; 1.0%, 13.3%; P = 0.02) and large HDL particles (15.5% decrease per a 1-SD or 3.5-μmol/L increment; 5.2%, 24.7%; P = 0.005). Omentin-1 was positively associated with mean VLDL size (3.8% increase per a 1-SD increment; 0.06%, 7.8%; P = 0.05). Adjustment for alcohol intervention, BMI, and other cytokines did not materially affect these associations.

Conclusions

Irisin and omentin-1 are stable within-person, inversely associated with each other, and closely related to lipoprotein profile. These molecules may be promising markers for cardiovascular risk.