Relationship between leptin, insulin, body composition and liver steatosis in non-diabetic moderate drinkers with normal transaminase levels

Dietary, anthropometric, and biochemical determinants of uric acid in free-living adults

BACKGROUND

High plasma uric acid (UA) is a prerequisite for gout and is also associated with the metabolic syndrome and its components and consequently risk factors for cardiovascular diseases. Hence, the management of UA serum concentrations would be essential for the treatment and/or prevention of human diseases and, to that end, it is necessary to know what the main factors that control the uricemia increase. The aim of this study was to evaluate the main factors associated with higher uricemia values analyzing diet, body composition and biochemical markers.

METHODS

415 both gender individuals aged 21 to 82 years who participated in a lifestyle modification project were studied. Anthropometric evaluation consisted of weight and height measurements with later BMI estimation. Waist circumference was also measured. The muscle mass (Muscle Mass Index - MMI) and fat percentage were measured by bioimpedance. Dietary intake was estimated by 24-hour recalls with later quantification of the servings on the Brazilian food pyramid and the Healthy Eating Index. Uric acid, glucose, triglycerides (TG), total cholesterol, urea, creatinine, gamma-GT, albumin and calcium and HDL-c were quantified in serum by the dry-chemistry method. LDL-c was estimated by the Friedewald equation and ultrasensitive C-reactive protein (CRP) by the immunochemiluminiscence method. Statistical analysis was performed by the SAS software package, version 9.1. Linear regression (odds ratio) was performed with a 95% confidence interval (CI) in order to observe the odds ratio for presenting UA above the last quartile (♂UA > 6.5 mg/dL and ♀ UA > 5 mg/dL). The level of significance adopted was lower than 5%.

RESULTS

Individuals with BMI ≥ 25 kg/m2 OR = 2.28(1.13-4.6) and lower MMI OR = 13.4 (5.21-34.56) showed greater chances of high UA levels even after all adjustments (gender, age, CRP, gamma-gt, LDL, creatinine, urea, albumin, HDL-c, TG, arterial hypertension and glucose). As regards biochemical markers, higher triglycerides OR = 2.76 (1.55-4.90), US-CRP OR = 2.77 (1.07-7.21) and urea OR = 2.53 (1.19-5.41) were associated with greater chances of high UA (adjusted for gender, age, BMI, waist circumference, MMI, glomerular filtration rate, and MS). No association was found between diet and UA.

CONCLUSIONS

The main factors associated with UA increase were altered BMI (overweight and obesity), muscle hypotrophy (MMI), higher levels of urea, triglycerides, and CRP. No dietary components were found among uricemia predictors.

Sex-dependent associations of leptin with metabolic syndrome-related variables: the Stanislas study

Serum leptin has been reported to be associated in a sex-dependent manner with C-reactive protein (CRP), independently of adiposity. We tested the hypothesis that leptin is associated, independently of anthropometry indexes and in a sex-dependent way, with other inflammatory markers and variables related to metabolic syndrome (MS). In 384 healthy middle-aged adults (192 men and 192 women) total fat mass (FM), waist circumference (WC), serum leptin and 15 MS-related parameters (systolic and diastolic blood pressure, triglycerides, cholesterol, high density lipoprotein (HDL)-cholesterol, apo AI and B, fasting glucose, uric acid, CRP, orosomucoid and haptoglobin levels and aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT) and gamma-glutamyl transferase (GGT) activities) were measured. After adjustment for age, alcohol and cigarette consumption, WC, and total FM, leptin concentration was significantly associated with serum triglycerides, total cholesterol, apo B, uric acid and haptoglobin concentrations and liver enzyme activity only in men, and with apo AI, HDL-cholesterol (only borderline) and CRP only in women. Sex interaction terms were significant for total cholesterol, apo B, HDL cholesterol, uric acid, ALAT and GGT, and borderline significant for triglycerides, apo AI and ASAT. In this healthy population, leptin is significantly associated with various MS factors, independently of WC and total FM, depending on gender. Our study provides further evidence of sex-related differences mediated by leptin in inflammatory mechanisms and other MS-related metabolic pathways.

Serum adipokine levels predictive of liver injury in non-alcoholic fatty liver disease

AIMS

The aim of this study was to determine whether serum levels of adipokines, including the ratio of serum adiponectin to leptin (A/L) levels could predict the severity of liver injury in patients with non-alcoholic fatty liver disease (NAFLD).

PATIENTS AND METHODS

Fifty-seven patients with biopsy-proven non-alcoholic steatohepatitis (NASH) (mean age 51+/-12, sex ratio 1), 17 with simple steatosis (mean age 47+/-12, sex ratio 1.4) and 10 controls without steatosis (mean age 51+/-11, sex ratio 4) were investigated. In all subjects, serum concentrations of triglycerides, ultrasensitive C reactive protein, leptin, adiponectin, soluble tumour necrosis factor receptor 1, interleukin (IL)-6 and Homeostasis Model Assessment Method (HOMA) were measured. Hepatic expression of adiponectin and its two receptors was assessed by quantitative reverse transcriptase polymerase chain reaction.

RESULTS

Body mass index (BMI) and HOMA were correlated positively with leptin levels (r=0.44 and 0.28 respectively) and negatively with the A/L ratio (r=0.51 and 0.41 respectively). Independent parameters associated with NASH vs steatosis were HOMA>3 [odds ratio (OR)=6.9] and A/L ratio <1.4 10(3) (OR=5.2). The combination of HOMA with A/L ratio showed an area under the receiver operating characteristic curve of 0.82 for distinguishing between NASH and steatosis. Extensive portal fibrosis was present in 17 (23%) patients with NAFLD. Three independent parameters were associated with fibrosis: age (OR=1.1), BMI (OR=1.3) and high IL-6 levels (OR=1.6). The hepatic expression of adiponectin receptor 2 was significantly higher in patients with NASH compared with controls and was related with necroinflammatory injury.

CONCLUSIONS

This study shows that in patients with NAFLD, the combination of HOMA with A/L ratio may be a useful non-invasive approach to appreciate the severity of liver damage.

The increase in plasma PAI-1 associated with insulin resistance may be mediated by the presence of hepatic steatosis

OBJECTIVE

Recent evidence suggests that plasminogen-activator inhibitor-1 (PAI-1) is abundantly produced by the fatty liver, but it is unclear whether hepatic steatosis (HS) can mediate the increase in plasma PAI-1 induced by insulin resistance/compensatory hyperinsulinemia (IR/CH).

METHODS AND RESULTS

To address this issue, we cross-sectionally evaluated IR/CH as area under the curve of plasma insulin (AUC-PI) concentrations during OGTT, metabolic profile, and ultrasound degree of HS in 235 healthy volunteers (132M, age: 60+/-7 years) with normal transaminase concentrations. Circulating PAI-1 was increased in subjects with classical features of IR/CH (overweight, high fasting and post-OGTT insulin and glucose, high triglycerides (TG), and low HDL-cholesterol), and significantly correlated to prevalence and degree of HS, but not to alcohol intake. In a multivariate model, AUC-PI, TG and degree of HS were independent predictors of plasma PAI-1 (R(2)=0.32). However, AUC-PI was significantly correlated to PAI-1 only in subjects with HS, suggesting an interaction between AUC-PI and HS. In addition, in the presence of HS and IR/CH, PAI-1 concentrations were increased to a similar extent both in heavy and moderate drinkers, suggesting that metabolic and alcoholic steatosis have a similar effect on the relationship between IR/CH and PAI-1.

CONCLUSION

These results support the hypothesis that HS has a major impact on the relationship between IR/CH and plasma PAI-1 concentrations, and this effect seems to be unaffected by the etiology of the HS.

The effect of red wine on plasma leptin levels and vasoactive factors from adipose tissue: A randomized crossover trial

AIMS

It has been reported that alcohol has multiple effects on appetite. To elucidate potential mechanisms we measured the levels of plasma leptin and the vasoactive factors after red wine intake.

METHODS

We conducted a randomized crossover trial to study the effect of red wine on the levels of leptin, TNF-alpha, TGF- beta(1), IL-6, ICAM-1, and VCAM-1 in healthy, non-smoking individuals. The subjects were randomized to drinking one glass of red wine (150 ml, 15 g alcohol) every day ('wine period') or to undergo a period of total abstention from alcohol ('abstention period'). After 3 weeks they switched the intervention group. Eighty-seven volunteers completed the study (mean age 50 years).

RESULTS

After 3 weeks' daily intake of red wine, plasma leptin was significantly increased (from 6308 pg/ml to 7402 pg/ml, P = 0.05). There was a marked gender difference, as leptin levels increased only in females (P = 0.012). When calculated as leptin/body mass index (BMI) ratio, the trend and results were similar. Red wine consumption had no significant effect on other vasoactive factors measured in this study.

CONCLUSION

Red wine increases levels of the appetite-regulating hormone leptin in females, but not in males. Whether red wine has an effect on appetite-regulation in its own right, remains to be solved.

Level of leptin in nonalcohic fatty liver of rats and preventive effects of Salvia miltiorrhiza injection

AIM: To detect the level of leptin in the nonalcohic fatty liver of rats and the preventive effects of Salvia miltiorrhiza (SM) injection.

METHODS: Male Sprague Dawley rats were selected randomly and given a fat-rich diet for 8 wk. The rats with fatty livers were randomly divided into model group, high-dose SM group, low-dose SM group and reduced glutathione control group. The serum level of leptin was detected by radioimmunoassay (RIA). The pathological changes in rat livers were observed.

RESULTS: The index of rat nonalcohic fatty liver was significantly higher than that in normal rats (3.09% ± 0.24% vs 2.63% ± 0.19%, t = 4.61, P = 0.00), while the level of leptin was markedly lower than that in normal rats (1.83 ± 0.44 μg/L vs 3.04 ± 0.55 μg/L, t = 5.08, P = 0.00). The level of leptin was dramatically elevated while the fat accumulation area in rat livers was decreased after high-dose SM injection as compared with that in model rats (leptin: 2.29 ± 0.46 μg/L vs 1.83 ± 0.44 μg/L, t = 2.33, P = 0.03; area: 1.45 ± 0.93 vs 2.40 ± 0.70, t = 2.60, P = 0.02).

CONCLUSION: SM injection can improve fat metabolism by increasing the level of leptin.

Dietary glycemic index and liver steatosis

BACKGROUND

Insulin resistance (IR) and liver steatosis (LS) are interlinked metabolic derangements whose prevalence is rapidly increasing, but the effect of dietary carbohydrate quality on LS is unknown.

OBJECTIVE

The objective was to describe the relation of IR and LS to total carbohydrate, total dietary fiber, and the glycemic index (GI) and glycemic load of the diet.

DESIGN

The study was a cross-sectional evaluation of 247 apparently healthy subjects who had no evidence of viral, toxic, or autoimmune hepatitis and who were unselected for alcohol intake. The homeostasis model assessment index was used as a surrogate measure of IR, and a liver echography was used as a proxy for LS grading. Dietary data were collected by using 3-d food records. Total carbohydrate intake, total dietary fiber, GI, and glycemic load were calculated by using a semiquantitative food-frequency questionnaire concerning the dietary sources of carbohydrates.

RESULTS

The prevalence of high-grade LS (HG-LS) increased significantly across quartiles of dietary GI (P for trend < 0.034): HG-LS in the 4th quartile (high GI) was twice that in the first 3 quartiles (low to medium GIs), whereas no relation was observed with total carbohydrates, total dietary fiber, or glycemic load. In insulin-sensitive subjects (first 3 quartiles of homeostasis model assessment index of IR), the prevalence of HG-LS did not differ significantly between GI groups, but, in insulin-resistant subjects (4th quartile of homeostasis model assessment index of IR), it was twice as high in those with high GI as in those with low to medium GIs (P = 0.005).

CONCLUSIONS

High-GI dietary habits are associated with HG-LS, particularly in insulin-resistant subjects. Dietary advice on the quality of carbohydrate sources therefore may be a complementary tool for preventing or treating LS of metabolic origin.

No significant effect of acute moderate alcohol intake on leptin levels in healthy male volunteers

As, for ethical reasons, it is difficult to investigate by an experiment the effect of acute intoxication on leptin levels in alcoholics, we tested the hypothesis of lowered levels as an effect of acute ethanol intake in healthy volunteers. The subjects comprised (1) 17 healthy male participants, recruited via newspaper advertisements [age 29+/-3.75 years, body mass index (BMI) 24.3+/-3.5, leptin at baseline 3.3+/-3.1 ng/ml]; (2) for comparison, leptin levels of 16 male alcoholic patients at day 1 of withdrawal were used. They were characterized as follows: (mean, median, standard deviation and range) age in years (41.1, 40.5, 10.2, 24, 57), BMI (23.3, 21.7, 5.4, 16.6, 37.5), 1,032 g of ethanol (median) consumed within the last 7 days, leptin levels 2.3 mg/ml. A placebo-controlled double-blind trial was performed. Leptin levels of blood samples were taken at baseline (t(1)), before ethanol intake (t(2)), when blood alcohol had reached its maximum (t(3)) and the morning after (t(4)). The oral dose of ethanol administered was 0.6 g/kg ethanol. (1) VOLUNTEERS: (a) the ethanol and placebo group exhibited leptin levels corresponding closely with levels measured at baseline (t(1)) (rs=0.85, p<0.0001) and follow-up (t(4)) (rs=0.768, p<0.0001). (b) Leptin levels for the placebo and the alcohol-consuming (verum) group did not differ significantly at baseline, after ethanol intake or on the morning after [Mann-Whitney U-test (p=0.669, p=1.0 and p=0.887, respectively)]. (2) Leptin levels in relation to BMI did not significantly differ at any measurement time in either group. (3) Leptin levels/BMI of the healthy volunteers at t(1) and t(4) were not significantly different from those of 16 alcoholics. The data do not support the hypothesis of a significant effect of acute moderate alcohol intake on leptin levels in healthy volunteers.