DXA-Determined Regional Adiposity Relates to Insulin Resistance in a Young Adult Population with Overweight andObesity

Obesity is a well-established risk factor for insulin resistance and type 2 diabetes mellitus, and body fat distribution has important implications for this metabolic risk. In this cross-sectional study, we used dual X-ray absorptiometry body composition data from 123 young adult participants with overweight or obesity, and correlatedwith 2 indices of insulin resistance calculated from oral glucose tolerance tests. Participants were 70% women, with mean (standard error) age 30.1 (0.6) yr, body mass index (BMI) 34.0 (0.6) kg/m², homeostatic model assessment of insulin resistance (HOMA-IR) of 2.1 (0.2), and Matsuda insulin sensitivity index (Matsuda ISI) of 5.8 (0.4). In women, the strongest correlations were observed with the android-to-gynoid ratio (r?=?0.52, p < 0.001 for HOMA-IR; r?=??0.46, p < 0.001 for Matsuda ISI), and these correlations remained significant after adjustment for BMI. For men, the strongest correlations were with android fat mass (r?=?0.40, p?=?0.01 for HOMA-IR; r = ?0.37, p?=?0.02 for Matsuda ISI). Visceral adipose tissue was correlated with HOMA-IR and Matsuda ISI in women, and only with Matsuda ISI in men. BMI correlated with HOMA-IR and with Matsuda ISI in both women and men. Regional adiposity determined by dual X-ray absorptiometry correlates with indices of insulin resistance in sedentary young adults with overweight and obesity.     

Low-level laser therapy (LLLT) combined with swimming training improved the lipid profile in rats fed with high-fat diet

Obesity and associated dyslipidemia is the fastest growing health problem throughout the world. The combination of exercise and low-level laser therapy (LLLT) could be a new approach to the treatment of obesity and associated disease. In this work, the effects of LLLT associated with exercises on the lipid metabolism in regular and high-fat diet rats were verified. We used 64 rats divided in eight groups with eight rats each, designed: SC, sedentary chow diet; SCL, sedentary chow diet laser, TC, trained chow diet; TCL, trained chow diet laser; SH, sedentary high-fat diet; SHL, sedentary high-fat diet laser; TH, trained high-fat diet; and THL, trained high-fat diet laser. The exercise used was swimming during 8 weeks/90 min daily and LLLT (GA-Al-As, 830 nm) dose of 4.7 J/point and total energy 9.4 J per animal, applied to both gastrocnemius muscles after exercise. We analyzed biochemical parameters, percentage of fat, hepatic and muscular glycogen and relative mass of tissue, and weight percentage gain. The statistical test used was ANOVA, with post hoc Tukey–Kramer for multiple analysis between groups, and the significant level was p?<?0.001, p?<?0.01, and p?<?0.05. LLLT decreased the total cholesterol (p?<?0.05), triglycerides (p?<?0.01), low-density lipoprotein cholesterol (p?<?0.05), and relative mass of fat tissue (p?<?0.05), suggesting increased metabolic activity and altered lipid pathways. The combination of exercise and LLLT increased the benefits of exercise alone. However, LLLT without exercise tended to increase body weight and fat content. LLLT may be a valuable addition to a regimen of diet and exercise for weight reduction and dyslipidemic control.     

Sex-specific relationships between insulin resistance and bone mineral content in Korean adolescents

The aim of this study was to examine sex-specific relationships between insulin resistance (IR) and bone mineral content (BMC) according to age group and weight status. A population-based sample of 618 Korean adolescents (315 male and 303 female), aged 10–19 years from the Fourth Korea National Health and Nutrition Examination Survey, 2009. They were divided into three age groups (10–12; 13–16; 17–19 years) and two weight groups (non-overweight vs. overweight). IR was assessed using the homeostatic model of assessment of IR (HOMA-IR). Soft tissue composition (fat and lean mass) and BMC of the whole body, proximal femur, and lumbar spine were measured by dual energy X-ray absorptiometry. Adiposity (body mass index, waist circumference, or soft tissue composition), age, height, total cholesterol, triglycerides, high density lipoprotein cholesterol, alkaline phosphatase, serum vitamin D, dietary calcium and energy intake, and menarche for females were adjusted using general linear models of a complex sampling design. Higher HOMA-IR was associated with a decrease in BMC in male adolescents aged 13–19 years after adjustment for adiposity and other confounders, while the associations were not significant in male adolescents aged 10–12 years and female adolescents. After adjustment for adiposity and confounders, the inverse associations between HOMA-IR and BMC were more consistent in non-overweight male adolescents than in other weight groups (overweight males and non-overweight and overweight females). The unfavorable effect of IR on BMC appears to be more obvious in males aged 13–19 years or non-overweight males than in females.     

Impact of diet,exercise end diet combined with exercise programs on plasma lipoprotein and adiponectin levels in obese girls

We studied the effect of three programs, diet restriction (D), individualized exercise training (E) at the maximal lipid oxidation point (LIPOXmax) and diet combined with exercise (D+E), on body mass, plasma lipoprotein and adiponectin levels in obese girls. Eighteen obese adolescents girls aged 12-14 years were studied. A longitudinal intervention was carried out, consisting of a two-month diet (D; -500 kcal·day-1), of individualized exercise (E; 4 days/week, 90 min·day-1) and of diet combined with exercise (D+E). Body mass, body mass index (BMI), body fat mass, waist circumference, substrate crossover point, LIPOXmax point, homeostasis model assessment (HOMA-IR) index, fasting levels of lipids and circulatory adiponectin, were measured in all subjects before and after the program. In subjects of the D+E group, body mass, BMI, body fat mass, waist circumference, HOMA-IR, low-density lipoprotein cholesterol (LDL-C) and total cholesterol / high-density lipoprotein cholesterol (TC/HDL-C) ratio were significantly lower, and HDL-C and adiponectin were higher after the program than that of subjects in the D or E groups. Diet/exercise improved the ability to oxidize lipids during exercise (crossover point: + 18.5 ± 3.4 of % Wmax; p < 0.01 and fat oxidation rate at LIPOXmax: + 89.7 ± 19.7 mg·min^-1; p < 0.01). In the D+E group, significant correlations were found between changes in body mass and adiponectin and between changes in the TC/HDL-C ratio and LIPOXmax. These findings show that the combined program of diet restriction and individualized exercise training at the LIPOXmax point is necessary to simultaneously improve body mass loss, adiponectin levels, as well as metabolic parameters, in obese girls.

Key points

• Diet combined with exercise training improved body composition, adiponectin levels and metabolic parameters in obese girls.
• Diet only decreases body mass and LDL-C without improving fat oxidation and HDL- C.
• Individualized exercise training at LIPOXmax point improved the HDL-C and the circulatory adiponectin levels with any change of LDL-C and body composition.

Key words: Obese girls, lipoprotein, adiponectin, exercise training, diet restriction     

Resistance Band Exercise Training Prevents the Progression of Metabolic Syndrome in Obese Postmenopausal Women

Metabolic syndrome (MetS) is classified as a combination of risk factors for cardiovascular disease (CVD), and postmenopausal women are specifically at an increased risk for MetS, in part due to the hormonal and metabolic changes that occur at the menopause transition. It is crucial to combat the components of MetS with appropriate lifestyle interventions in this population, such as exercise. This study aimed to examine the effects of a resistance band exercise training program in obese postmenopausal women with MetS. A total 35 postmenopausal women were randomly assigned to either a control group (CON, n = 17) or a resistance band exercise training group (EX, n = 18). Participants in the EX group trained 3days/week. Levels of blood glucose, insulin, homeostatic model of insulin resistance (HOMA-IR), blood lipid profile, anthropometrics, and blood pressure (BP) were measured at baseline and after the exercise intervention. There were significant group by time interactions (p < 0.05) for blood glucose (Δ-4.5 mg/dl), insulin (Δ -1.3 μU/ml), HOMA-IR (Δ -0.6), triglycerides (Δ -9.4 mg/dl), low-density lipoprotein cholesterol(Δ -10.8 mg/dl), systolic BP(Δ -3.4 mmHg), body fat percentage (Δ -3.0 %), and waist circumference (Δ -3.4 cm), which significantly decreased (p < 0.05), and lean body mass (Δ 0.7 kg) and high-density lipoprotein cholesterol (Δ 5.1 mg/dl), which significantly increased (p < 0.05) after EX compared to no change in CON. The present study indicates that resistance band exercise training may be an effective therapeutic intervention to combat the components of MetS in this population, potentially reducing the risk for the development of CVD.Key points

• There are findings in the study that support the use of resistance band exercise for reducing risks for MetS in this population.
• There were significant improvements in insulin, glucose, HOMA-IR, and blood lipid profiles following the exercise training program.
• Body mass, BMI, BF%, SBP, and waist circumference were significantly decreased, while LBM significantly increased after 12 weeks of exercise training program.
• This is the first study to evaluate the impact of resistance band exercise training on risk factors for MetS in obese postmenopausal women.

Key words: Hyperinsulinemia, HOMA-IR, insulin resistance, resistance training, triglycerides     

When is the best moment to apply photobiomodulation therapy (PBMT) when associated to a treadmill endurance-training program? A randomized,triple-blinded,placebo-controlled clinical trial

Photobiomodulation therapy (PBMT) employing low-level laser therapy (LLLT) and/or light emitting diode therapy (LEDT) has emerged as an electrophysical intervention that could be associated with aerobic training to enhance beneficial effects of aerobic exercise. However, the best moment to perform irradiation with PBMT in aerobic training has not been elucidated. The aim of this study was to assess the effects of PBMT applied before and/or after each training session and to evaluate outcomes of the endurance-training program associated with PBMT. Seventy-seven healthy volunteers completed the treadmill-training protocol performed for 12 weeks, with 3 sessions per week. PBMT was performed before and/or after each training session (17 sites on each lower limb, using a cluster of 12 diodes: 4?×?905 nm super-pulsed laser diodes, 4?×?875 nm infrared LEDs, and 4?×?640 nm red LEDs, dose of 30 J per site). Volunteers were randomized in four groups according to the treatment they would receive before and after each training session: PBMT before + PBMT after, PBMT before + placebo after, placebo before + PBMT after, and placebo before + placebo after. Assessments were performed before the start of the protocol and after 4, 8, and 12 weeks of training. Primary outcome was time until exhaustion; secondary outcome measures were oxygen uptake and body fat. PBMT applied before and after aerobic exercise training sessions (PBMT before + PBMT after group) significantly increased (p?<?0.05) the percentage of change of time until exhaustion and oxygen uptake compared to the group treated with placebo before and after aerobic exercise training sessions (placebo before + placebo after group) at 4th, 8th, and 12th week. PBMT applied before and after aerobic exercise training sessions (PBMT before + PBMT after group) also significantly improved (p?<?0.05) the percentage of change of body fat compared to the group treated with placebo before and after aerobic exercise training sessions (placebo before + placebo after group) at 8th and 12th week. PBMT applied before and after sessions of aerobic training during 12 weeks can increase the time-to-exhaustion and oxygen uptake and also decrease the body fat in healthy volunteers when compared to placebo irradiation before and after exercise sessions. Our outcomes show that PBMT applied before and after endurance-training exercise sessions lead to improvement of endurance three times faster than exercise only.     

Circuit Resistance Exercise Improves Glycemic Control and Adipokines in Females with Type 2 Diabetes Mellitus

The aim of study was to evaluate whether circuit resistance exercise (CE) improves glycemic control and adipokine levels in comparison with walking exercise (WE) in 15 adult postmenopausal Korean females with type 2 diabetes mellitus (T2DM). The participants were randomly assigned to either the CE or WE group. Subjects exercised for 1 h, three times per week for 12 weeks. The parameters measured were body composition, respiratory rate, blood glucose, insulin and adipokines. The body composition of the CE group showed a significant reduction (all p < 0.05) in body weight, body mass index (BMI), and percentage of body fat and a significant increase in muscle mass. Respiratory function was also significantly increased in the CE group. Additionally, hemoglobin A1c (HbA1c) changed favorably in the CE group, as were the concentrations of adipokines such as retinol binding protein 4 (RBP-4) (p < 0.05), adiponectin (p < 0.01), and monocyte chemoattractant protein-1 (MCP-1) (p < 0.01). In addition, significant correlations with CE were evident for homeostatic model assessment insulin resistance (HOMA-IR) and glucose (r = 0.69, p < 0.001), muscle mass and glucose (r = 0.45, p < 0.05), and muscle mass and HbA1c (r = 0.39, p < 0.05). The beneficial effects of CE include the development of muscle mass, which effectively increases glucose use and reduces the amount of insulin required. Thus, our results suggest that CE improves glycemic control and adipokines resulting from incrementally increased muscle mass and reductions of body weight, BMI and percentage of body fat for T2DM postmenopausal Korean women.

Key points

• CE-induced weight loss and muscle mass increment increases the level of adiponectin secreted by adipocytes due to heightened glucose utilization and fat oxidation.
• Aerobic exercise decreases body weight, fat and adipokines in high intensity and frequency, while resistance exercise decreases these parameters in low intensity, time and frequency.
• CE can improves glycemic control and adipokines resulting from reduction of body fat postmenopausal Korean women with T2DM.

Key words: Circuit resistance exercise, walking exercise, glycemic control, adipokines, type 2 diabetes.     

Altered abdominal fat distribution and its association with the serum lipid profile in non-diabetic haemodialysis patients.

BACKGROUND: Disturbances of lipid and carbohydrate metabolism may be associated with the distribution of abdominal adiposity. However, little is known about the alteration of abdominal adiposity and its association with the serum lipid profile in haemodialysis patients. METHODS: We evaluated the distribution of abdominal adiposity by using computed tomography and examined its relationship with the serum lipid profile in 92 non-diabetic haemodialysis patients and 80 control subjects with normal renal function. Since the mean body mass index (BMI) and total body fat mass were significantly lower in the haemodialysis patients than in the control subjects, the subcutaneous abdominal fat area and the visceral fat area were standardized by body mass index and compared between the haemodialysis patients and the control subjects. RESULTS: Mean subcutaneous fat area/body mass index (SFA/BMI) was significantly lower, and mean visceral fat area/body mass index (VFA/BMI) was significantly higher in the haemodialysis patients (SFA/BMI, 2.40+/-0.12; VFA/BMI, 2.28+/-0.15) than in the control subjects (SFA/BMI, 3.75+/-0.21, P<0.01; VFA/BMI, 1.65+/-0.15, P<0.01). Consequently, visceral fat area/ subcutaneous fat area ratio was significantly higher in the haemodialysis patients (1.05+/-0.07) than in the control subjects (0.46+/-0.04, P<0.01). A scattered plot of visceral fat area relative to BMI revealed that visceral fat area was higher in the haemodialysis patients than in the control subjects at any BMI level. A simple regression analysis showed that BMI, total body fat mass, subcutaneous fat area and visceral fat area were all associated with serum triglycerides and the atherogenic index, (total cholesterol-HDL cholesterol)/HDL cholesterol. Furthermore, a multiple regression analysis indicated that the visceral fat area was the best predictor for either the atherogenic index or triglycerides among these fat components. CONCLUSIONS: These data indicate that haemodialysis patients exhibited a visceral fat accumulation irrespective of BMI, and this shift of abdominal adiposity might be associated with disturbance of the serum lipid profile in non-diabetic haemodialysis patients.     

Effect of Laparoscopic Roux-en-Y gastric Bypass on Body Composition and Insulin Resistance in Chinese Patients with Type 2 Diabetes Mellitus

Background

This study aims to assess the effect of laparoscopic Roux-en-Y gastric bypass (LRYGB) on body composition, fat distribution, and insulin resistance (IR) in Chinese type 2 diabetes mellitus (T2DM) patients.

Methods

Eighteen patients with T2DM were studied before and 3 months post LRYGB. Fasting plasma glucose (FPG), fasting insulin (FINS), and triglyceride (TG) were measured. IR index was determined using the homeostasis model assessment of insulin resistance (HOMA-IR). Body composition and fat distribution were measured by dual-energy X-ray absorptiometry (DXA). Fat mass (FM), muscle mass (MM), bone mineral content (BMC), and percent fat mass (%FM) at the whole body and five body regions including the arms, legs, trunk, android, and gynoid were obtained from DXA scans.

Results

HOMA-IR decreased from 5.02 at baseline to 1.43 3 months post LRYGB (p?<?0.05). There was significant decrease in total and regional body mass and body fat (all p?<?0.05). A significant reduction was observed in %FM at every tested body region (all p?<?0.05). There was more fat mass loss (31.03 %) in android region than any other tested body region. Preoperative android %FM was significantly correlated with IR (r?=?0.49, p?<?0.05). Changes in android FM showed significant correlations with changes in IR, FPG, FINS, and TG (r?=?0.54, 0.64, 0.54, and 0.67, respectively; all p?<?0.05).

Conclusions

Body composition in Chinese T2DM patients is rebalanced after LRYGB. Reduction of central obesity can result in improvement of IR, and android fat distribution may be a good indicator of postoperative benefits for LRYGB.     

Effect of 830 nm low-level laser therapy applied before high-intensity exercises on skeletal muscle recovery in athletes

Our aim was to investigate the immediate effects of bilateral, 830 nm, low-level laser therapy (LLLT) on high-intensity exercise and biochemical markers of skeletal muscle recovery, in a randomised, double-blind, placebo-controlled, crossover trial set in a sports physiotherapy clinic. Twenty male athletes (nine professional volleyball players and eleven adolescent soccer players) participated. Active LLLT (830 nm wavelength, 100 mW, spot size 0.0028 cm², 3–4 J per point) or an identical placebo LLLT was delivered to five points in the rectus femoris muscle (bilaterally). The main outcome measures were the work performed in the Wingate test: 30 s of maximum cycling with a load of 7.5% of body weight, and the measurement of blood lactate (BL) and creatine kinase (CK) levels before and after exercise. There was no significant difference in the work performed during the Wingate test (P?>?0.05) between subjects given active LLLT and those given placebo LLLT. For volleyball athletes, the change in CK levels from before to after the exercise test was significantly lower (P?=?0.0133) for those given active LLLT (2.52 U l^?1 ± 7.04 U l^?1) than for those given placebo LLLT (28.49 U l^?1 ± 22.62 U l^?1). For the soccer athletes, the change in blood lactate levels from before exercise to 15 min after exercise was significantly lower (P?<?0.01) in the group subjected to active LLLT (8.55 mmol l^?1 ± 2.14 mmol l^?1) than in the group subjected to placebo LLLT (10.52 mmol l^?1 ± 1.82 mmol l^?1). LLLT irradiation before the Wingate test seemed to inhibit an expected post-exercise increase in CK level and to accelerate post-exercise lactate removal without affecting test performance. These findings suggest that LLLT may be of benefit in accelerating post-exercise recovery.     

Low-level laser therapy combined to functional exercise on treatment of fibromyalgia: a double-blind randomized clinical trial

This study aims to investigate the effects of low-level laser therapy (LLLT) combined to a functional exercise program on treatment of FM. A double-blind and placebo-controlled randomized clinical trial composed of 22 women divided into two groups: placebo group (functional exercise program associated with placebo phototherapy n?=?11) and laser group (same exercise program associated with active phototherapy; n?=?11). Each session lasted from 40 to 60 min and was performed three times a week for 8 weeks. Phototherapy (808 nm, 100 mW, 4 J, and 142.85 J/cm² per point) was bilaterally applied to different points of the quadriceps (8), hamstrings (6), and triceps sural muscles (3) immediately after each exercise session. Pre- and post-intervention evaluations regarding pain (sites, intensity, and threshold), functional performance (balance, functional tests), muscle performance (flexibility and isokinetic variables), depression, and quality of life were conducted. A reduction in pain and improvement in functional and muscular performance, depression, and quality of life were observed in both groups (p?<?0.05); however, with no significant differences between them (p?>?0.05). In conclusion, the benefic effects of functional exercise were not improved by combination with LLLT.     

The effect of low-level laser therapy on oxidative stress and functional fitness in aged rats subjected to swimming: an aerobic exercise

The aim of the present study was to determine whether low-level laser therapy (LLLT) in conjunction with aerobic training interferes with oxidative stress, thereby influencing the performance of old rats participating in swimming. Thirty Wistar rats (Norvegicus albinus) (24 aged and six young) were tested. The older animals were randomly divided into aged-control, aged-exercise, aged-LLLT, aged-LLLT/exercise, and young-control. Aerobic capacity (VO₂max^0.75) was analyzed before and after the training period. The exercise groups were trained for 6 weeks, and the LLLT was applied at 808 nm and 4 J energy. The rats were euthanized, and muscle tissue was collected to analyze the index of lipid peroxidation thiobarbituric acid reactive substances (TBARS), glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) activities. VO₂ ^0.75max values in the aged-LLLT/exercise group were significantly higher from those in the baseline older group (p <0.01) and the LLLT and exercise group (p <0.05). The results indicate that the activities of CAT, SOD, and GPx were higher and statistically significant (p <0.05) in the LLLT/exercise group than those in the LLLT and exercise groups. Young animals presented lesser and statistically significant activities of antioxidant enzymes compared to the aged group. The LLLT/exercise group and the LLLT and exercise group could also mitigate the concentration of TBARS (p?>?0.05). Laser therapy in conjunction with aerobic training may reduce oxidative stress, as well as increase VO2 ^0.75max, indicating that an aerobic exercise such as swimming increases speed and improves performance in aged animals treated with LLLT.     

Correlation of serum leptin concentrations with body composition and gender in Taiwanese hemodialysis patients without diabetes

OBJECTIVE: (1) To evaluate the impact of body composition and gender on serum leptin concentration in hemodialysis patients. (2) To study which marker of adiposity is most appropriate in Taiwanese hemodialysis patients without diabetes. (3) To compare the nutrition status between nonlean and lean subjects. PATIENTS AND METHODS: Serum leptin concentrations were measured by radioimmunoassay collected in 88 hemodialysis patients without diabetes. Bioimpedance analysis was performed to determine percent fat mass (%FM), lean body mass (LM), and total body water (TBW). Body mass index (BMI) was calculated as weight/height2. Albumin and transferrin were measured by standard laboratory methods. RESULTS: Serum leptin levels were more correlated with percent fat mass (r = 0.697; P < 0.001) than with body fat mass (r = 0.672; P < 0.001) or with BMI (r = 0.594; P < 0.001) in the group as a whole and in each subgroup when analyzed separately by gender. The mean (+/- SD) serum leptin levels were 32.5 +/- 34.3 ng mL(-1) in women subjects and 13.6 +/- 15.5 ng mL(-1) in men subjects (P < 0.001). Multiple regression analysis in all subjects revealed that serum leptin levels were independently affected by percent fat mass and gender. Adiposity corrected serum leptin, such as leptin/BMI, leptin/percent fat mass, and leptin/body fat mass was significantly different between sexes (P < 0.001). The significantly higher serum leptin concentrations in women than in men were observed in obese subjects with BMI > 25 kg/m2 (P < 0.001) as well as nonobese subjects with BMI < 25 kg/m2 (P < 0.05). There were no differences in lean mass and albumin between nonlean and lean subjects. CONCLUSION: Gender and adiposity had impact on serum leptin levels in hemodialysis patients without diabetes. In terms of adiposity, serum leptin levels had stronger correlation with percent fat mass than with body fat mass (FM) or BMI in Taiwanese hemodialysis patients. Steady-state serum leptin levels could serve as valuable clinical markers for the body adiposity in stable hemodialysis patients without diabetes. Protein malnutrition markers and lean mass should be checked in lean subjects for the evaluation of the protein stores of hemodialysis patients.     

Improved insulin sensitivity after gastric bypass correlates with decreased total body fat,but not with changes in free fatty acids

Background

Increased plasma free fatty acids (FFAs) are considered one of the key elements in the pathogenesis of insulin resistance (IR) and type 2 diabetes (T2DM). We hypothesize that, in diabetic patients undergoing laparoscopic Roux-en-Y gastric bypass (LRYGB), a postoperative decrease in FFA will correlate with improved insulin sensitivity (Si).

Methods

A total of 30 obese [body mass index ((BMI) >35 kg/m²] patients with a diagnosis of T2DM were studied preoperatively and 12 months after LRYGB in a prospective cohort study. Collected data included intravenous glucose tolerance test (IVGTT), total body composition by dual-energy X-ray absorptiometry and plasma levels of FFA. Si analysis from the IVGTT was estimated from minimal model analysis. Pre- and postoperative variables were compared using a paired sample t test. Relationships between changes in variables were determined with Pearson’s correlation test.

Results

Twelve months after LRYGB the study population showed a significant decrease in BMI (p = 0.001), FFA (p = 0.03), and total body fat (p = 0.03), with an increase in Si (p = 0.001). Postoperative changes in Si significantly correlated (Pearson’s r = –0.53, p = 0.01) with change in total body fat, but not with changes in plasma FFA (Pearson’s r = –0.22, p = 0.31).

Conclusions

Our study challenges the notion that IR is mediated to a significant degree by changes in plasma FFA concentration. Instead, changes in adiposity and consequently changes in adipokine release can be the key players in determining remission of T2DM after LRYGB.     

Assessment of skeletal muscle triglyceride content by (1)H nuclear magnetic resonance spectroscopy in lean and obese adolescents: relationships to insulin sensitivity, total body fat, and central adiposity

The metabolism and composition of skeletal muscle tissue is of special interest because it is a primary site of insulin action and plays a key role in the pathogenesis of insulin resistance. Intramyocellular (IMCL) triglyceride stores are an accessible form of energy that may decrease skeletal muscle glucose utilization, thereby contributing to impaired glucose metabolism. Because of the invasive nature of muscle biopsies, there is limited, if any, information about intramuscular lipid stores in children. The development of (1)H nuclear magnetic resonance (NMR) spectroscopy provides a unique noninvasive alternative method that differentiates intracellular fat from intercellular fat in muscle tissue. The present study was performed to determine whether IMCL and extramyocellular (EMCL) lipid contents are increased early in the development of juvenile obesity and to explore the relationships between IMCL and EMCL to in vivo insulin sensitivity, independently of total body fat and central adiposity in obese and nonobese adolescents. Eight nonobese (BMI 21 kg/m(2), age 11-16 years) and 14 obese (BMI 35 +/- 1.5 kg/m(2), age 11-15 years) adolescents underwent 1) (1)H-NMR spectroscopy to noninvasively quantify IMCL and EMCL triglyceride content of the soleus muscle, 2) a 2-h euglycemic-hyperinsulinemic clamp (40 mU.m(-2).min(-1)) to assess insulin sensitivity, 3) a dual-energy X-ray absorptiometry scan to measure total percent body fat, and 4) magnetic resonance imaging to measure abdominal fat distribution. Both the IMCL and EMCL content of the soleus muscle were significantly greater in the obese adolescents than in the lean control subjects. A strong inverse correlation was found between IMCL and insulin sensitivity, which persisted and became even stronger after controlling for percent total body fat and abdominal subcutaneous fat mass (partial correlation r = -0.73, P < 0.01) but not when adjusting for visceral fat (r = - 0.54, P < 0.08). In obese adolescents, increase in total body fat and central adiposity were accompanied by higher IMCL and EMCL lipid stores. The striking relationships between both IMCL and EMCL with insulin sensitivity in childhood suggest that these findings are not a consequence of aging but occur early in the natural course of obesity.     

Obesity is a major determinant of the association of C-reactive protein levels and the metabolic syndrome in type 2 diabetes

The inflammatory factor C-reactive protein (CRP) and the fibrinolytic variables fibrinogen and plasminogen activator-1 (PAI-1) are associated with long-term cardiovascular morbidity. To determine the contribution of body adiposity (BMI), insulin sensitivity (homeostasis model assessment of insulin resistance [HOMA-IR], and glycemia (HbA(1c) [A1C]) to the levels of these inflammatory and fibrinolytic variables in recently diagnosed (相似文献   

The association between body composition,leptin levels and glucose dysregulation in youth with cystic fibrosis

BackgroundOptimization of nutritional status is recommended in patients with cystic fibrosis (CF) given the association between lower body mass index (BMI) and poor clinical outcomes. However, higher BMI and body fat correlate with glucose impairment and higher leptin levels in the general population. Differences in body composition and leptin levels between the categories of glucose tolerance were assessed in youth with CF and healthy controls.MethodsIn a cross-sectional study, 59 adolescents and young adults with CF and 15 healthy controls matched by age and gender, underwent body composition analysis using dual energy X-ray absorptiometry (DXA) and a 2-hour oral glucose tolerance test (OGTT). Measures of insulin sensitivity, β-cell insulin secretion and fasting leptin levels were obtained.ResultsOf the participants with CF, 62% were classified as abnormal glucose tolerant and 22% with cystic fibrosis related diabetes (CFRD). Patients with CFRD had a lower fat mass index (FMI) z-score, wt z-score and leptin levels compared to the control group (-1.86 vs. - 0.59, p=0.01; -1.86 vs 0.44, p=<0.001 and 7.9 vs vs. 27.7 µg/L, p=0.01). Leptin correlated positively with FMI z-score, BMI, weight z-score and indices of insulin secretion. FMI z-score correlated positively with higher insulin resistance (HOMA-IR), and lower insulin sensitivity (Matsuda index) (r=0.31; p =0.01 and r=-0.29; p=0.02, respectively) in the CF group.ConclusionsThis study shows that despite new therapeutic strategies, youth with CF have lower body fat, weight z-score and leptin levels, particularly in subjects with early onset CFRD.     

Correlation of Serum Leptin Concentrations with Body Composition and Gender in Taiwanese Hemodialysis Patients without Diabetes

Objective.?(1) To evaluate the impact of body composition and gender on serum leptin concentration in hemodialysis patients. (2) To study which marker of adiposity is most appropriate in Taiwanese hemodialysis patients without diabetes. (3) To compare the nutrition status between nonlean and lean subjects. Patients and Methods.?Serum leptin concentrations were measured by radioimmunoassay collected in 88 hemodialysis patients without diabetes. Bioimpedance analysis was performed to determine percent fat mass (%FM), lean body mass (LM), and total body water (TBW). Body mass index (BMI) was calculated as weight/height². Albumin and transferrin were measured by standard laboratory methods. Results.?Serum leptin levels were more correlated with percent fat mass (r = 0.697; P<0.001) than with body fat mass (r = 0.672; P<0.001) or with BMI (r = 0.594; P<0.001) in the group as a whole and in each subgroup when analyzed separately by gender. The mean (±SD) serum leptin levels were 32.5 ± 34.3 ng mL^?1 in women subjects and 13.6 ± 15.5 ng mL^?1 in men subjects (P<0.001). Multiple regression analysis in all subjects revealed that serum leptin levels were independently affected by percent fat mass and gender. Adiposity corrected serum leptin, such as leptin/BMI, leptin/percent fat mass, and leptin/body fat mass was significantly different between sexes (P<0.001). The significantly higher serum leptin concentrations in women than in men were observed in obese subjects with BMI >25 kg/m² (P<0.001) as well as nonobese subjects with BMI<25 kg/m² (P<0.05). There were no differences in lean mass and albumin between nonlean and lean subjects. Conclusion.?Gender and adiposity had impact on serum leptin levels in hemodialysis patients without diabetes. In terms of adiposity, serum leptin levels had stronger correlation with percent fat mass than with body fat mass (FM) or BMI in Taiwanese hemodialysis patients. Steady-state serum leptin levels could serve as valuable clinical markers for the body adiposity in stable hemodialysis patients without diabetes. Protein malnutrition markers and lean mass should be checked in lean subjects for the evaluation of the protein stores of hemodialysis patients.     

Nutrition,insulin resistance and dysfunctional adipose tissue determine the different components of metabolic syndrome

Obesity is an excessive accumulation of body fat that may be harmful to health. Today, obesity is a major public health problem, affecting in greater or lesser proportion all demographic groups. Obesity is estimated by body mass index(BMI) in a clinical setting, but BMI reports neither body composition nor the location of excess body fat. Deaths from cardiovascular diseases, cancer and diabetes accounted for approximately 65% of all deaths, and adiposity and mainly abdominal adiposity are associated with all these disorders. Adipose tissue could expand to inflexibility levels. Then, adiposity is associated with a state of low-grade chronic inflammation, with increased tumor necrosis factor-α and interleukin-6 release, which interfere with adipose cell differentiation, and the action pattern of adiponectin and leptin until the adipose tissue begins to be dysfunctional. In this state the subject presents insulin resistance and hyperinsulinemia, probably the first step of a dysfunctional metabolic system. Subsequent to central obesity, insulin resistance, hyperglycemia, hypertriglyceridemia, hypoalphalipoproteinemia, hypertension and fatty liver are grouped in the so-called metabolic syndrome(MetS). In subjects with MetS an energy balance is critical to maintain a healthy body weight, mainly limiting the intake of high energy density foods(fat). However, high-carbohydrate rich(CHO) diets increase postprandial peaks of insulin and glucose. Triglyceride-rich lipoproteins are also increased, which interferes with reverse cholesterol transport lowering highdensity lipoprotein cholesterol. In addition, CHO-rich diets could move fat from peripheral to central deposits and reduce adiponectin activity in peripheral adipose tissue. All these are improved with monounsaturated fatty acid-rich diets. Lastly, increased portions of ω-3 and ω-6 fatty acids also decrease triglyceride levels, and complement the healthy diet that is recommended in patients with MetS.     

Maximal oxygen uptake and exercise tolerance are improved in rats with heart failure subjected to low-level laser therapy associated with resistance training

Exercise tolerance and maximal oxygen uptake (VO_2max) are reduced in heart failure (HF). The influence of combined resistance training (RT) and low-level laser therapy (LLLT) on exercise tolerance and VO_2max in HF has not yet been explored. The aim of this study was to evaluate the influence of combined RT and LLLT on VO_2max and exercise tolerance in rats with HF induced by myocardial infarction (MI). Rats were allocated to sedentary sham (Sed-Sham, n?=?12), sedentary heart failure (Sed-HF, n?=?9), RT heart failure (RT-HF, n?=?7) and RT associated with LLLT heart failure (RT?+?LLLT-HF, n?=?7) groups. After MI or sham surgery, rats underwent a RT and LLLT protocol (applied immediately after RT) for 8 weeks. VO_2max and exercise tolerance were evaluated at the end of protocol. HF rats subjected to LLLT combined with RT showed higher VO_2basal (41 %), VO_2max (40 %), VO_2reserve (39 %), run distance (46 %), time to exhaustion (30 %) and maximal velocity (22 %) compared with HF rats that underwent RT alone. LLLT associated with RT improved oxygen uptake and exercise tolerance compared with RT alone in HF rats.