Hyperleptinaemia: the missing link in the, metabolic syndrome?

Anti-diabetic potential of Urtica Dioica: current knowledge and future direction

Aim

This review summarizes studies on the anti-diabetic effect of Urtica Dioica (UD) in Type-2-diabetes.

Materials and methods

We studied worldwide traditional medicines, old texts, and published literature for anti-diabetic effect of UD. Electronic databases comprising PubMed, Web of Science, Science Direct, Scopus and Google Scholar were searched to collect articles published between 1990 and 2021 years.

Results

Our literature investigation suggests UD as a glucose lowering, blood lipid regulating, anti-inflammatory and anti-oxidation plant.

Conclusions

UD's anti-diabetic properties make it potential traditional therapeutics for lowering the clinical manifestations of T2DM through affecting hyperglycemia and therefore suggest it as a proper medication with no or limited side effects.

Nocturnal non-dipping on 24-h Ambulatory Blood Pressure Monitoring in children and adolescents with obesity is associated with higher total cholesterol levels

BACKGROUND

Few studies indicate the occurrence of abnormal nocturnal dipping of blood pressure (BP) in 35-50% of children and adolescents with obesity. The relation between that phenomenon and metabolic complications of obesity remains unclear. To evaluate the association between disorders of glucose and lipid metabolism, and nocturnal non-dipping in pediatric patients with obesity.

METHODS

In 207 children (53.14% girls, mean age 14 (range 2-17), mean BMI Z-SCORE 4.38, range 2.07-10.74) standard 24-h Ambulatory Blood Pressure Monitoring was performed. Normal dipping was defined as a ≥ 10% decline in BP during the night.

RESULTS

There were 106 (51.21%) cases of non-dippers. The mean 24-h nocturnal systolic BP (SBP) reduction (%) was 9.9 ± 5.5. The mean 24-h nocturnal diastolic BP (DBP) reduction (%) was 15.8 ± 8.5. There was a significant correlation between BMI Z-SCORE and mean day-time SBP (r = 0.14 P = .042). There are positive correlations between 24-h heart rate (beats/min) and BMI Z-SCORE (r = 0.15, P = .027), between fasting glucose and systolic BP Z-SCORE (r = 0.17, P = .03) and between mean diastolic BP and LDL cholesterol (r = 0.23, P = .004). Total cholesterol level was significantly higher in non-dippers (4.34 vs. 3.99 mmol/L, P = .034). There were no significant differences between non-dippers and dippers regarding fasting glucose (4.6 vs. 4.8 mmol/L), 120'post load glucose (5.7 vs. 5.9 mmol/L), insulin (19 vs. 20.2 µIU/mL), HOMA-IR (2.36 vs. 2.44), LDL cholesterol (2.64 vs. 2.51 mmol/L), HDL cholesterol (1.06 vs. 1.03 mmol/L) or triglycerides (1.36 vs. 1.34 mmol/L) levels.

CONCLUSION

Nocturnal non-dipping is frequent in pediatric patients with obesity. It is associated with higher total cholesterol levels.

Prospective Associations of Serum Adiponectin, Leptin, and Leptin-Adiponectin Ratio with Incidence of Metabolic Syndrome: The Korean Genome and Epidemiology Study

Although the role of adiponectin and leptin in the etiology of metabolic syndrome (MetS) has been explored in various populations, limited knowledge is available on the prospective association of adiponectin and leptin with the risk of MetS development. The present study aimed to evaluate the associations of adiponectin, leptin, and the leptin-adiponectin (LA) ratio with the future risk of MetS in middle-aged and older Korean adults. Using a prospective, population-based Ansan-Ansung cohort of the Korean Genome and Epidemiology Study (KoGES), 2691 Korean adults (1317 men and 1374 women) were included in the present study. Serum adiponectin and leptin concentrations were measured using commonly available enzyme-linked immunosorbent assay kits. Multivariable Cox proportional hazard models were used to investigate the relationships of the different adiponectin and leptin concentrations and LA ratio with the incident MetS. During a mean follow-up of 6.75 years, a total of 359 (27.26%) men and 385 (28.02%) women were identified as developing new-onset MetS. After controlling for covariates, higher adiponectin levels were associated with lower incidence of MetS (hazard ratio (HR) for third vs. first tertile: 0.53, 95% confidence interval (CI): 0.40–0.70 for men and HR: 0.54, 95% CI: 0.42–0.71 for women), while higher leptin levels (HR for third vs. first tertile: 2.88, 95% CI: 2.01–4.13 for men and HR: 1.55, 95% CI: 1.13–2.13 for women) and LA ratio (HR for third vs. first tertile: 3.07, 95% CI: 2.13–4.44 for men and HR: 1.94, 95% CI: 1.41–2.66 for women) were associated with an increased incidence of MetS. Among men, in the fully adjusted models an increase by one standard deviation (SD) in adiponectin levels was associated with a 10% decrease in MetS risk (HR per SD: 0.90, 95% CI: 0.85–0.95) while leptin and LA ratio was associated with a 5% (HR per SD: 1.05, 95% CI: 1.01–1.08) and 40% (HR per SD: 1.40, 95% CI: 1.22–1.62) increase in MetS risk, respectively. Among women, a significant association with MetS risk was observed only in adiponectin levels (HR per SD: 0.91, 95% CI: 0.88–0.95). We found that higher adiponectin level was associated with a lower risk of MetS, while higher leptin level and LA ratio were associated with elevated MetS incidence, irrespective of body mass index at baseline in both Korean men and women. Adiponectin and leptin levels and LA ratio could play a role as a useful biomarker in the prediction of future MetS development among middle-aged and older Koreans.

Effects of pioglitazone treatment on blood leptin levels in patients with type 2 diabetes

AIMS/INTRODUCTION

The aim of the present study was to carry out a meta-analysis of randomized controlled trials (RCTs) that investigated the effects of pioglitazone on blood leptin levels in patients with type 2 diabetes.

MATERIALS AND METHODS

Literature searches were carried out using Medline, the Cochrane Controlled Trials Registry and ClinicalTrials.gov, and RCTs that investigated the effects of pioglitazone on blood leptin levels in patients with type 2 diabetes were selected. Standardized mean differences and 95% confidence intervals were calculated.

RESULTS

A total of 10 RCTs met the eligibility criteria and were included in the meta-analysis. Significantly lower blood leptin levels were observed in the pioglitazone group (standardized mean difference -0.58, 95% confidence interval -1.12 to -0.05%, P = 0.03) than in the placebo group. There was no significant difference in blood leptin levels observed between the pioglitazone and oral antidiabetic drug groups (standardized mean difference -0.01, 95% confidence interval -0.20 to 0.19%, P = 0.93).

CONCLUSIONS

There was a significant difference in blood leptin levels between the pioglitazone and placebo groups. However, relatively few RCTs were included in the study, and there was a high level of statistical heterogeneity; we believe that this could have affected the results.

Clinical Conditions and Predictive Markers of Non-Dipper Profile in Hypertensive Patients

Hypertension remains one of the primary causes of premature cardiovascular mortality representing a major independent risk factor.

The importance of ambulatory blood pressure monitoring in clinical evaluation of hypertensive patients, beyond diagnosis, is the identification of circadian dipping/non-dipping profile. The non-dipper pattern in hypertensive and normotensive patients is associated with significant target organ damage and worse outcomes, as an increased cardiovascular risk condition. Non-dipping pattern has been found to be associated with specific clinical conditions. Obesity, diabetes mellitus, metabolic syndrome, obstructive sleep apnea syndrome, chronic kidney disease, autonomic and baroreflex dysfunctions, salt sensitivity, hormonal changes, gender and age were extensively studied. Research efforts are focused on recognizing and exploring predictive markers of abnormal blood pressure circadian pattern. Previous studies acknowledge that red cell distribution width, mean platelet volume, fibrinogen level, C-reactive protein, serum uric acid and gamma-glutamyltransferase, are independently significant and positive associated to non-dipping pattern. Moreover, research on new biomarkers are conducted: Chitinase 3-Like-Protein 1, atrial and B-type natriuretic peptide, brain-derived neurotrophic factor, chemerin, sphingomyelin and the G972R polymorphism of the insulin receptor substrate-1 gene. This review summarizes the current knowledge of different clinical conditions and biomarkers associated with the non-dipper profile in hypertensive patients.

Effects of metformin treatment on blood leptin and ghrelin levels in patients with type 2 diabetes mellitus

BACKGROUND

The aim of the present study was to conduct a meta-analysis of randomized controlled trials (RCTs) that investigated the effects of metformin on blood leptin and ghrelin levels in patients with type 2 diabetes mellitus (T2DM).

METHODS

Literature searches were performed using MEDLINE, Cochrane Controlled Trials Registry, and ClinicalTrials.gov, and RCTs that investigated the effects of metformin on blood leptin and ghrelin levels in patients with T2DM were selected. Standardized mean differences (SMDs) and 95 % confidence intervals (CIs) were calculated.

RESULTS

Twelve RCTs met the eligibility criteria and were included in the meta-analysis. There was no significant difference in blood leptin between the metformin and control groups (SMD 0.03; 95 % CI -0.35 %, 0.42 %; P = 0.86), although there was a significant difference in blood leptin levels between the metformin group and the group on oral antidiabetic drugs (OADs) other than metformin (SMD -0.39; 95 % CI -0.76 %, -0.01 %; P = 0.04). There were no significant differences in blood ghrelin levels.

CONCLUSIONS

Metformin treatment was not associated with a decrease in blood leptin levels in patients with T2DM compared with levels in patients in the control group. Moreover, metformin treatment was not associated with increases in blood ghrelin levels compared with the control and other OADs groups. However, blood leptin levels were significantly lower in the metformin compared with the other OADs group.

Obesity: A Perspective from Hypertension

The prevalence of obesity-related hypertension is high worldwide and has become a major health issue. The mechanisms by which obesity relates to hypertensive disease are still under intense research scrutiny, and include altered hemodynamics, impaired sodium homeostasis, renal dysfunction, autonomic nervous system imbalance, endocrine alterations, oxidative stress and inflammation, and vascular injury. Most of these contributing factors interact with each other at multiple levels. Thus, as a multifactorial and complex disease, obesity-related hypertension should be recognized as a distinctive form of hypertension, and specific considerations should apply in planning therapeutic approaches to treat obese individuals with high blood pressure.

Hepatocellular Carcinoma in Obesity, Type 2 Diabetes, and NAFLD

Hepatocellular carcinoma (HCC) is the second commonest cause of cancer death worldwide. Rather than falling as a result of prevention and treatments for viral hepatitis, an increase is evident in developed nations consequent to the rising prevalence of obesity and type 2 diabetes mellitus (T2DM)-the two major risk factors for nonalcoholic fatty liver disease (NAFLD). The majority of patients with HCC complicating these conditions present with advanced disease as the tools for surveillance are inadequate, and the "at-risk" population is not well characterized. This review will summarize the epidemiological evidence linking obesity, T2DM, and NAFLD with HCC, what is known about the pathogenic mechanisms involved, as well as their relevance for clinicians managing patients at risk. There will also be an overview of the "unmet needs" surrounding this topic, with suggestions for the direction translational research should take in order to prevent progression of NAFLD to HCC, to improve early detection of HCC in those with NAFLD, as well as to improve outcomes for those affected.

Leptin and metabolic syndrome in patients with Duchenne/Becker muscular dystrophy

OBJECTIVES

To determine whether patients with Duchenne/Becker muscular dystrophy (DMD/BMD) have components of metabolic syndrome (MetSy) and to evaluate whether leptin is associated with components of MetSy.

METHODS

This study included 78 patients (nine, <6 years of age; 54, 6 to <16 years of age; and 15 patients, ≥16 years of age). Obesity and body fat mass were determined by waist circumference and dual-energy X-ray absorptiometry, respectively. A 12-h fasting blood sample was collected in the morning. Patients were categorized into four groups according to the number of criteria for MetSy: group 0: none; group 1: one; group 2: two and group 3: three or more criteria.

RESULTS

All age groups showed components of MetSy. The concentration of these components was significantly higher in patients ≥16 years old. The prevalence of hypertriglyceridemia was from ~37% to 46% in all age groups. The prevalence of MetSy was 7.1% for patients from 6 to <16 years of age and 24% for patients ≥16 years of age. Serum leptin levels increased significantly (P < 0.05) with age; the highest (13.43 ± 9.4 ng/ml) value was observed in patients >16 years of age. Total leptin was correlated with the number of patients with MetSy (r = 0.383; P = 0.001).

CONCLUSIONS

Components of MetSy are significant in patients with DMD/BMD. A high prevalence of hypertriglyceridemia was observed. Younger patients with DMD/BMD have risk factors for MetSy. Although leptin increased according to different degrees of MetSy, this relation disappeared when the body fat was corrected by leptin; therefore, the association could be caused by a common risk factor-fat.

Leptin Is Associated With Persistence of Hyperglycemia in Acute Pancreatitis: A Prospective Clinical Study

Adipokines have many homeostatic roles, including modulation of glucose metabolism, but their role in the pathophysiology of hyperglycemia associated with acute and critical illnesses in general, and acute pancreatitis (AP) in particular, is largely unknown. This study aimed to investigate the relationship between a panel of adipokines and hyperglycemia in the early course of AP, as well as the role of adipokines as predictors of AP severity.Adiponectin, leptin, omentin, resistin, and visfatin were measured on a daily basis in the first 72 hours after hospital admission. A first set of analyses was undertaken with admission glycemia stratified by severity, and a second set of analyses was undertaken based on persistence of early hyperglycemia. All of the analyses were adjusted for confounders.A total of 32 patients with AP were included in this study. None of the studied adipokines was significantly associated with glucose level on admission. Leptin was significantly (P = 0.003) increased in patients with persistent hyperglycemia. Adiponectin was significantly associated with the Acute Physiology and Chronic Health Evaluation II (APACHE II) score in patients with persistent hyperglycemia (P = 0.015), visfatin with APACHE II score in patients with persistent hyperglycemia (P = 0.014), and omentin with APACHE II score in all of the patients regardless of the presence or absence of hyperglycemia (P = 0.021).Leptin is significantly associated with persistent hyperglycemia in the early course of AP. Omentin has a potential to become an accurate predictor of AP severity.

Gender Specific Association of Serum Leptin and Insulinemic Indices with Nonalcoholic Fatty Liver Disease in Prediabetic Subjects

Adipose tissue-derived hormone leptin plays a functional role in glucose tolerance through its effects on insulin secretion and insulin sensitivity which also represent the risk factors for nonalcoholic fatty liver disease (NAFLD). The present study explored the gender specific association of serum leptin and insulinemic indices with NAFLD in Bangladeshi prediabetic subjects. Under a cross-sectional analytical design a total of 110 ultrasound examined prediabetic subjects, aged 25-68 years consisting of 57.3% male (55.6% non NAFLD and 44.4% NAFLD) and 42.7% female (57.4% non NAFLD and 42.6% NAFLD), were investigated. Insulin secretory function (HOMA%B) and insulin sensitivity (HOMA%S) were calculated from homeostasis model assessment (HOMA). Serum leptin showed significant positive correlation with fasting insulin (r = 0.530, P = 0.004), postprandial insulin (r = 0.384, P = 0.042) and HOMA-IR (r = 0.541, P = 0.003) as well as significant negative correlation with HOMA%S (r = -0.388, P = 0.046) and HOMA%B (r = -0.356, P = 0.039) in male prediabetic subjects with NAFLD. In multiple linear regression analysis, log transformed leptin showed significant positive association with HOMA-IR (β = 0.706, P <0.001) after adjusting the effects of body mass index (BMI), triglyceride (TG) and HOMA%B in male subjects with NAFLD. In binary logistic regression analysis, only log leptin [OR 1.29 95% (C.I) (1.11-1.51), P = 0.001] in male subjects as well as HOMA%B [OR 0.94 95% (C.I) (0.89-0.98), P = 0.012], HOMA-IR [OR 3.30 95% (C.I) (0.99-10.95), P = 0.049] and log leptin [OR 1.10 95% (C.I) (1.01-1.20), P = 0.026] in female subjects were found to be independent determinants of NAFLD after adjusting the BMI and TG. Serum leptin seems to have an association with NAFLD both in male and female prediabetic subjects and this association in turn, is mediated by insulin secretory dysfunction and insulin resistance among these subjects.

Hyperleptinemia May Protect From Cardio-Vascular Complications: A Small Georgian Study

BACKGROUND AND AIM: Leptin was assessed to play a coordinating role in obesity and its cardio-vascular complications, however the findings are conflicting and further clinical investigation is required. The aim of the present study was to evaluate the association of serum leptin with cardio-vascular risk factors in different body mass index and age groups.MATERIALS AND METHODS:  One hundred and forty nine female patients were enrolled in the study and divided into groups according to body mass index (BMI) and age. Following measurements were carried out: height, weight, BMI, waist circumference, blood pressure. Venous blood sample was obtained for plasma leptin, insulin, glucose and lipid profile analysis. Insulin resistance index was calculated for each patient. Body fat distribution was measured using Dual energy X-ray Absorbtiometry.RESULTS: The lowest leptin concentration was observed in overweight patients, the highest concentration was seen in obese patients. The difference between leptin levels were not observed in age groups. Leptin positively correlated with high density lipoprotein cholesterol levels in obese and elder patients.CONCLUSION: Leptin might act as a preventive measure for cardiovascular complications only in the presence of sufficient amount of fat mass. Further studies are warranted in order to support these results.

Temporal trends in overweight and obesity among Nicobarese adults in Nicobar Islands, India, 1960s-1999

SUMMARY

OBJECTIVE

The aim of the present study is to assess the change in the prevalence of overweight and obesity among Nicobarese adults from 1960s to 1999 using WHO recommendations for the classification of overweight and obesity.

METHODS

The sample includes 774 individuals (424 men and 350 women) during 1960s and 484 individuals (259 men and 225 women) during 1999, aged 20-64 years from Nicobar Islands, India. Height (cm), weight (kg) and sitting height (cm) were measured and BMI (kg/m(2)) was calculated. Overweight and obesity were defined as BMI ≥ 25 kg/m(2) and BMI ≥ 30 kg/m(2), respectively.

RESULTS

There was significant increase of height, weight and BMI among both the men and women of 20-39, and 40 and above years age groups. However, the higher magnitude of increment was observed in 20-39 years. The prevalence of overweight increased from 5.42% to 22.01% among men and from 4% to 21.78% among women, while obese individual was absent during 1960s and the prevalence of obesity increased to 2.70% in men and 8.89% in women. The magnitude of increment was higher among women compared to men.

CONCLUSION

The results indicate remarkable increase in the prevalence of both overweight and obesity among Nicobarese adult in Nicobar Islands.

Obesity-related cardiorenal disease: the benefits of bariatric surgery

The inexorable increase in the prevalence of obesity is a global health concern, which will result in a concomitant escalation in health-care costs. Obesity-related metabolic syndrome affects approximately 25% of adults and is associated with cardiovascular and renal disease. The heart and kidneys are physiologically interdependent, and the pathological effects of obesity can lead to cardiorenal syndrome and, ultimately, kidney and heart failure. Weight loss can prevent or ameliorate obesity-related cardiorenal syndrome, but long-term maintenance of a healthy weight has been difficult to achieve through lifestyle changes or pharmacotherapy. Bariatric surgery offers both sustained weight loss and favourable metabolic changes, including dramatic improvements in glycaemic control and symptoms of type 2 diabetes mellitus. Procedures such as Roux-en-Y gastric bypass offer immediate multisystemic benefits, including bile flow alteration, reduced gastric size, anatomical gut rearrangement and altered flow of nutrients, vagal manipulation and enteric hormone modulation. In patients with cardiorenal syndrome, bariatric surgery also offers renoprotection and cardioprotection, and attenuates both kidney and heart failure by improving organ perfusion and reversing metabolic dysfunction. However, further research is required to understand how bariatric surgery acts on the cardiorenal axis, and its pioneering role in novel treatments and interventions for cardiorenal disease.

The leptin to adiponectin ratio is a good biomarker for the prevalence of metabolic syndrome, dependent on visceral fat accumulation and endurance fitness in obese patients with diabetes mellitus

BACKGROUND

We investigated the contribution of adiponectin or leptin on the prevalence of metabolic syndrome (MS), while also taking cardiorespiratory fitness and visceral fat accumulation into account regarding diabetes patients.

METHODS

Japanese male patients (n = 77) with either impaired glucose tolerance (IGT) or type 2 diabetes mellitus were divided into three tertiles according to their adipocytokine levels. A logistic regression analysis was performed after adjusting for age to investigate the association between the adipocytokine levels and the prevalence of MS based on World Health Organization (WHO) criteria.

RESULTS

The visceral fat area (VFA) and maximal oxygen uptake ([Formula: see text] O(2)max) were found to be significantly different within the tertiles regarding the leptin and adiponectin levels and the adiponectin-to-leptin (A/L) ratio. The low tertile of leptin showed a significantly lower odds ratio (OR) for prevalence of MS than that in the high group. Both the low and the medium tertiles of adiponectin showed a significantly higher OR for prevalence of SM than that of the high group. Especially, the low tertile of A/L ratio had about an eight times higher prevalence of MS than the high tertile, and the difference was significant. However, when both the VFA and/or [Formula: see text] O(2)max were added to the logistic regression model as adjusting factors, all of these significant differences disappeared.

CONCLUSION

The A/L ratio is suggested to be a good biomarker for the prevalence of MS in comparison to the adiponectin and leptin levels alone. However, these relationships are dependent on abdominal fat accumulation and/or cardiorespiratory fitness levels.

Correlation of adiponectin and leptin with insulin resistance: a pilot study in healthy north Indian population

The increasing incidence of obesity, leading to metabolic complications is now recognized as a major public-health problem. Insulin resistance is a central abnormality of the metabolic syndrome, or syndrome X, originally hypothesized by Reaven Insulin resistance is more strongly linked to intra abdominal fat than to fat in other depots. Adipose tissue secretes numerous factors (adipokines) known to markedly influence lipid and glucose/insulin metabolism, oxidative stress, and cardiovascular integrity. Some of these adipokines have been shown to directly or indirectly affect insulin sensitivity through modulation of insulin signaling and the molecules involved in glucose and lipid metabolism. A pilot study was conducted with 80 healthy subjects who were non diabetic, non hypertensive and having no family history of hypertension, the aim was to evaluate the correlation of adiponectin and leptin levels with obesity and insulin resistance markers in healthy north Indian adult population. Serum leptin, adiponectin and insulin was estimated by sandwich ELISA method. In our study, Leptin correlated significantly with BMI (P value of 0.0000), WC (P value = 0.007), and HC (P value = 0.000). leptin showed significant positive correlation with fasting insulin (P value 0.002), post prandial insulin (P value = 0.000) and HOMA-IR (P value = 0.002). Adiponectin showed significant positive correlation with triglycerides (P value = 0.038), strong negative correlation with HDL-cholesterol (P value = 0.017). Serum concentrations of leptin are associated with central body fat distribution. Insulin resistance and adiponectin is associated with dyslipidemia and these all disorders may ultimately lead to metabolic syndrome.

Association of plasma leptin levels and insulin resistance in diabetic women: a cross-sectional analysis in an Iranian population with different results in men and women

OBJECTIVES

The objective of this study was to assess the association of serum leptin levels with insulin resistance (IR), metabolic syndrome (MetS), lipid levels, and glucose control in an Iranian type 2 diabetic population.

FINDINGS

In this cross-sectional analysis, 132 type 2 diabetic patients (79 women) and 71 healthy non-diabetic and non-hypertensive individuals (40 women; as control subjects) were included. Homeostasis model assessment (HOMA) of insulin values ≥ 1.8 for females and 1.7 for males was regarded as the cut-point of IR. MetS was defined according to updated 2005 NCEP ATP III criteria. The leptin correlated with HOMA-IR values without adjustment (r = 0.24; p < 0.005) and with adjustment for sex and diabetes (r = 0.44; p < 0.005). Sex had significant effect on the BMI adjusted association of HOMA-IR (quintiles) and leptin (df = 4 F(12.7) = 3.5; p = 0.011). In diabetic women (but not men), leptin levels were different between those with and without IR (27.3 ± 1.9 vs. 18.2 ± 3.3; p < 0.05). BMI adjusted leptin values were different between subjects with and without MetS (22.2 ± 1.7 vs.14.8 ± 1.2; p < 0.001). No association was noticed between BMI-adjusted leptin with glycated hemoglobin or blood lipid levels.

CONCLUSIONS

In this study, plasma leptin concentration correlated with IR independent of the effect of obesity in female but not male diabetic subjects.

Leptin in hepatocellular carcinoma

The risk factors for hepatocellular carcinoma (HCC) development have been established, and include chronic hepatitis B and C, heavy alcohol consumption, and aflatoxins. In fact, 5%-30% of patients with HCC still lack a readily identifiable risk factor. It has been reported that the majority of ‘‘cryptogenic’’ HCC may be attributed to nonalcoholic fatty liver disease, the hepatic presentation of the metabolic syndrome (MS). Obesity is associated with the development of the MS. Recently, adipose tissue has been considered as an endocrine organ because of its capacity to secrete a variety of cytokines, which are collectively known as the adipokines. Leptin, the product of the obese gene, is mainly produced by adipose tissue. Since leptin was first characterized in 1994, accumulated literature has demonstrated the involvement of this adipokine in several areas of human physiology. After binding to its receptor, leptin initiates a cascade of signaling events and subsequent cellular effects. In addition to being the regulatory mediator of energy homeostasis, several in vitro studies have demonstrated the fibrogenic role of leptin in the liver. Furthermore, the deregulated expression of leptin and its receptor have been demonstrated to be associated with a variety of metabolic disorders as well as human cancers. Most importantly, direct evidence supporting the inhibitory and/or activating role of leptin in the process of carcinogenesis and progression of human HCC has been accumulating rapidly. This review aims to provide important insights into the potential mechanisms of leptin in the development of HCC. Hopefully, further investigations will shed light on a new therapeutic target in HCC.

Mechanisms of obesity-induced hypertension

The relationship between obesity and hypertension is well established both in children and adults. The mechanisms through which obesity directly causes hypertension are still an area of research. Activation of the sympathetic nervous system has been considered to have an important function in the pathogenesis of obesity-related hypertension. The arterial-pressure control mechanism of diuresis and natriuresis, according to the principle of infinite feedback gain, seems to be shifted toward higher blood-pressure levels in obese individuals. During the early phases of obesity, primary sodium retention exists as a result of increase in renal tubular reabsorption. Extracellular-fluid volume is expanded and the kidney-fluid apparatus is resetted to a hypertensive level, consistent with a model of hypertension because of volume overload. Plasma renin activity, angiotensinogen, angiotensin II and aldosterone values display significant increase during obesity. Insulin resistance and inflammation may promote an altered profile of vascular function and consequently hypertension. Leptin and other neuropeptides are possible links between obesity and the development of hypertension. Obesity should be considered as a chronic medical condition, which is likely to require long-term treatment. Understanding of the mechanisms associated with obesity-related hypertension is essential for successful treatment strategies.

Differential metabolic effects of pravastatin and simvastatin in hypercholesterolemic patients

BACKGROUND

Lipophilic and hydrophilic statins have different effects on adiponectin and insulin resistance in experimental studies and different effects on the rate of onset of new diabetes in large scale clinical studies. Therefore, we hypothesized that simvastatin and pravastatin may have differential metabolic effects in hypercholesterolemic patients.

METHODS

This was a randomized, single-blind, placebo-controlled, parallel study. Age, gender, and body mass index were matched. Forty-three patients were given placebo, simvastatin 20mg, or pravastatin 40 mg, respectively once daily for 2 months.

RESULTS

Simvastatin and pravastatin therapy significantly changed lipoprotein levels and improved flow-mediated dilation after 2 months when compared with baseline (P<0.001) or placebo treatment (P<0.001 by ANOVA). Simvastatin therapy significantly increased insulin levels (mean % changes; 127%, P=0.014) and decreased plasma adiponectin levels (10%, P=0.012) and insulin sensitivity as assessed by QUICKI (6%, P=0.007) when compared with baseline. By contrast, pravastatin therapy did not significantly change insulin levels (-3%, P=0.437) but significantly increased plasma adiponectin levels (9%, P=0.011) and insulin sensitivity (6%, P=0.008) when compared with baseline. In addition, these effects of simvastatin were significant when compared with pravastatin (P<0.001 for insulin levels by ANOVA on Ranks, P<0.001 for adiponectin and P=0.001 for QUICKI by ANOVA). When compared with baseline, simvastatin significantly increased plasma leptin levels (35%, P=0.028), but pravastatin did not (1%, P=0.822).

CONCLUSIONS

Despite causing comparable changes in lipoprotein and endothelium-dependent dilation, simvastatin and pravastatin therapy had differential metabolic effects in hypercholesterolemic patients that may be clinically relevant.

Is there a unique measuring method to assess obesity?

Az elhízás mértékének megállapítására nincs egységesen elfogadott mérőmódszer.Célkitűzésannak megállapítása, hogy milyen összefüggés van a testtömegindex, a testzsírszázalék és a haskörfogat alapján felállított kategóriák és az inzulinrezisztencia, a szérumleptin és -rezisztin koncentrációja között.Módszerek:A vizsgálatot 101 fiú és 115 lány részvételével végezték el. Mérték a testmagasságot, a testtömeget, a haskörfogatot, a testösszetételt pedig InBody3 bioimpedancia-készülékkel határozták meg. A testtömegindexet és a testzsírszázalékot a készülék számította ki. A szérumban a glükózinzulin-, a leptin- és a rezisztintartalom került meghatározásra. Az inzulinrezisztencia mértékét a HOMAIRmodellel becsülték meg.Eredmények:A testzsírszázalék, a szérumleptin és -rezisztin koncentrációja szignifikánsan nagyobb volt a lányok, mint a fiúk esetében. A testtömegindex, a testzsírszázalék és a haskörfogat növekedésével összhangban szignifikánsan nőtt mind a HOMAIR-érték, mind a szérumleptin koncentrációja. A túlsúlyos fiúk – akik, a testzsírszázalék alapján elhízottaknak bizonyultak – szérumleptin-koncentrációja szignifikánsan nagyobb volt, mint nem elhízott társaiké.Következtetés:Mind az epidemiológiai vizsgálatokban, mind a táplálkozási intervenciókban szükséges lenne a testösszetétel meghatározása a szervezetben lezajló biokémiai változások nyomon követése érdekében.

A novel oxidized low-density lipoprotein marker, serum amyloid A-LDL, is associated with obesity and the metabolic syndrome

BACKGROUND

The putative association between the novel oxidized low-density lipoprotein markers, serum amyloid A-LDL (SAA-LDL) and alpha1-antitrypsin-LDL (AT-LDL), and obesity and the metabolic syndrome (MetS) has not been previously studied. In the present report, we investigated the levels of SAA-LDL and AT-LDL in relation to the components of the MetS. We also assessed the effect of weight reduction therapy on serum SAA-LDL and AT-LDL levels among obese subjects.

METHODS

The study population included 421 obese Japanese outpatients (185 men and 236 women, mean age: 51.1 years) enrolled in the multicenter Japan Obesity and Metabolic Syndrome Study (JOMS). The novel oxidized low-density lipoprotein markers, serum SAA-LDL and AT-LDL, were measured in all participants.

RESULTS

Circulating SAA-LDL levels were independently associated with the presence and the number of components of the MetS. SAA-LDL levels were also significantly and independently correlated with high-sensitivity C-reactive protein. Notably, successful weight reduction resulted in a significant decrease in circulating SAA-LDL concentrations. Levels of AT-LDL were not associated with the MetS.

CONCLUSIONS

We documented, for the first time, that serum SAA-LDL levels correlate positively with the number of components of the MetS and weight reduction. Whether SAA-LDL may be involved in the pathophysiology of MetS and atherosclerosis deserves further investigation.

Serum leptin and its relationship with metabolic variables in Arabs with type 2 diabetes mellitus

BACKGROUND AND OBJECTIVES

Most studies on serum leptin in type 2 diabetes mellitus have focused on white populations. We studied serum leptin concentrations and parameters related to glycemic control and the association between leptin levels and anthropometric and metabolic factors in Arab patients with type 2 diabetes and in Arab control subjects.

SUBJECTS AND METHODS

Ninety-two patients (65 females and 27 males) with type 2 diabetes and 69 matched normal control subjects (48 females and 21 males) were included. Anthropometric measures (including body mass index [BMI] and waist:hip ratio) were assessed in all subjects. After an overnight fast, blood was collected for serum leptin assay. Other metabolic parameters including glucose, insulin, C-peptide, intact proinsulin, insulin resistance index (HOMA-IR), insulin-like growth factor 1 (IGF-1), lipids and hemoglobin A1c (HbA1c) were determined.

RESULTS

Fasting serum leptin levels, IGF-1 and high-density lipoprotein (HDL) cholesterol were similar in patients with type 2 diabetes and control subjects. When obese subjects (BMI > or =30 kg/m2) were analyzed separately, serum levels of leptin were significantly lower in patients compared to controls. In contrast, patients had higher fasting glucose, insulin, C-peptide, intact proinsulin, insulin resistance, total cholesterol, triglycerides, HbA1c, and a larger waist circumference and waist-to-hip ratio than controls. Serum leptin correlated positively with BMI, negatively with waist-to-hip ratio, and demonstrated no relationship to other parameters.

CONCLUSION

Patients with type 2 diabetes in an Arab ethnic population showed evidence of an unfavorable metabolic profile despite having leptin levels similar to controls. Obesity influences serum leptin levels more significantly in type 2 diabetes, in which leptin levels tends to be low.

Distribution of adiponectin, leptin, and metabolic correlates of insulin resistance: a longitudinal study in British children; 1: Prepuberty (EarlyBird 15)

BACKGROUND

The emergence of type 2 diabetes in young populations has mirrored a rising prevalence of obesity and insulin resistance during childhood and adolescence. At the same time, the role of adipokines as links between obesity and insulin resistance is becoming more appreciated. We sought to establish age- and sex-specific distributions of metabolic correlates of insulin resistance in healthy prepubertal children.

METHODS

We collected fasting blood samples from a contemporary cohort of 307 British children at ages 5, 6, 7, and 8 years and measured insulin, glucose, triglycerides, total and HDL cholesterol, urate, glycohemoglobin, sex hormone-binding globulin (SHBG), leptin, and adiponectin. We used homeostasis model assessment (HOMA 2) to estimate insulin sensitivity (HOMA-%S) and beta-cell function (HOMA-%B). Anthropometric measures included body mass index.

RESULTS

Body mass index increased from age 5 to 8 years (P < 0.001). HOMA-%B decreased (P < 0.001) and HOMA-%S increased (P < 0.05), but glucose also increased (P < 0.001) whereas glycohemoglobin decreased (P < 0.001). Consistent with the rise in insulin sensitivity, HDL cholesterol increased (P < 0.001) and triglycerides decreased (NS), whereas adiponectin decreased (P = 0.02). The patterns were similar in boys and girls, although girls were less insulin sensitive throughout. Accordingly, triglycerides tended to be higher in the girls, and HDL cholesterol and SHBG lower.

CONCLUSIONS

The metabolic disturbances associated with insulin resistance appear to be more advanced in girls. Markers of metabolic health improve in both sexes from 5 to 8 years, despite rising adiposity.

Rat models of caloric intake and activity: relationships to animal physiology and human health

Every rodent experiment is based on important parameters concerning the levels of caloric intake and physical activity. In many cases, these decisions are not made consciously, but are based on traditional models. For experimental models directed at the study of caloric intake and activity, the selection of parameters is usually aimed at modeling human conditions, the ultimate goal of which is to gain insight into the pathophysiology of the disease process in man. In each model, it is important to understand the influence of diet, exercise, and genetic background on physiology and the development of disease states. Along the continuum of energy intake from caloric restriction to high-fat feeding, and of energy output from total inactivity to forced exercise, a number of models are used to study different disease states. In this paper, we will evaluate the influence of the quantity and composition of diet and exercise in several animal models, and will discuss how each model can be applied to various human conditions. This review will be limited to traditional models using the rat as the experimental animal, and although it is not an exhaustive list, the models presented are those most commonly represented in the literature. We will also review the mechanisms by which each affects rat physiology, and will compare these to the analogous mechanisms in the modeled human disease state. We hope that the information presented here will help researchers make choices among the available models and will encourage discussion on the interpretation and extrapolation of results obtained from traditional and novel rodent experiments on diet, exercise, and chronic disease.

The associations between serum leptin, adiponectin and intercellular adhesion molecule-1 in hypercholesterolemic patients

We examined the associations between adiponectin or leptin and serum ICAM-1 levels in seventy-six hypercholesterolemic patients (mean age 59 yrs, 25 males and 51 females, LDL-cholesterol>=130mg/dL at screening). Blood lipid profiles and HOMA-IR derived from fasting glucose and insulin concentrations were determined. Serum levels of adiponectin, leptin and ICAM-1 were analyzed using ELISA. The results showed that serum levels of leptin were positively associated with serum levels of ICAM-1 independent of age, sex and BMI (r =0.392, p<0.001). Serum levels of adiponectin were negatively associated with serum levels of ICAM-1 independent of age, sex and BMI (r =-0.343, p<0.005). Stepwise multiple linear regression analysis showed that serum leptin was an independent factor to be associated with serum ICAM-1 levels after adjusting for age, sex, BMI, alcohol intake, smoking status, blood lipids such as total cholesterol, triglyceride, HDL cholesterol and LDL cholesterol and HOMA-IR (p<0.001). With respect to adiponectin, its association with serum ICAM-1 was attenuated but still significant when further adjustments were made for age, sex, BMI, alcohol intake, smoking status, blood lipids such as total cholesterol, triglyceride, HDL cholesterol and LDL cholesterol and HOMA-IR (p<0.005). In conclusion, this study suggests that adiponectin and leptin are associated with endothelial derived inflammation.

Inflammatory process in type 2 diabetes: The role of cytokines

Population-based studies have shown strong relationship between inflammatory markers and metabolic disturbances, obesity, and atherosclerosis, whereas inflammation has been considered as a "common soil" between these clinical entities and type 2 diabetes (T2D). The accumulation of macrophages in adipose tissue (AT), the common origin of macrophages and adipocytes, the prevalent presence of peripheral mononuclear cells, and apoptotic beta cells by themselves seem to be the sources of inflammation present in T2D, since they generate the mediators of the inflammatory processes, namely cytokines. The main cytokines involved in the pathogenesis of T2D are interleukin-1beta (IL-1beta), with an action similar to the one present in type 1 diabetes, tumor necrosis factor-alpha (TNF-alpha), and IL-6, considered as the main regulators of inflammation, leptin, more recently introduced, and several others, such as monocyte chemoattractant protein-1, resistin, adiponectin, with either deleterious or beneficial effects in diabetic pathogenesis. The characterization of these molecules targeted diabetes treatment beyond the classical interventions with lifestyle changes and pharmaceutical agents, and toward the determination of specific molecular pathways that lead to low grade chronic inflammatory state mainly due to an immune system's unbalance.

Plasma Levels of Leptin Are Associated with the Plasma Levels of LDL Conjugated Dienes in Children

BACKGROUND

Plasma leptin has been suggested to be involved in the proatherogenic process by increasing oxidative stress. We investigated the relationship between leptin and plasma conjugated diene formation, a measure of LDL oxidation in vivo in schoolchildren.

METHODS

We measured blood lipid profiles, plasma antioxidant vitamins, leptin and diene conjugation in LDL of 118 Korean children (35 overweight-obese vs. 83 normal weight children).

RESULTS

The overweight-obese children showed significantly higher levels of leptin (p < 0.0001), conjugated dienes (p = 0.02), total cholesterol (p < 0.05), triglyceride (p < 0.005) and LDL cholesterol (p < 0.01) and a significantly lower level of plasma lycopene (p < 0.0001) compared with the normal weight children. When all the subjects were classified into the three groups by tertiles of leptin levels, significant differences in circulating conjugated dienes (p < 0.05), lipid-corrected lycopene (p < 0.05), total cholesterol (p < 0.05), triglyceride (p < 0.05) and LDL cholesterol (p < 0.05) were found among the three groups.

CONCLUSION

Our results showed that leptin was positively associated with the LDL conjugated diene formation, which might be related to the proatherogenic process in schoolchildren.

Human soluble leptin receptor concentration in healthy offspring of hypertensive parents

Essential hypertension is associated with increased plasma leptin levels and decreased human soluble leptin receptor (hsLR) concentration. The aim of this study was to determine whether the concentration of hsLR differs among offspring of hypertensive compared with nonhypertensive parents. Subjects in the 2 groups were matched for age, sex, and body mass index. Forty-six (24 male, 22 female; mean age, 18+/-3 years; body mass index, 22.4+/-1.4 kg/m2) healthy offspring of hypertensive parents (group A) and 50 (28 male, 22 female; mean age, 18+/-3.2 years; body mass index, 22.6+/-1.7 kg/m2) healthy offspring of healthy parents (group B) were studied. The hsLR concentration (enzyme-linked immunosorbent assay method) and leptin plasma levels (radioimmunoassay method) were determined in the study population. Plasma leptin levels were significantly higher (10+/-5 vs 6+/-3 ng/mL; P<.001), while hsLR concentration was significantly lower (20+/-7 vs 29+/-8 U/mL; P<.001) in group A compared with group B. Our findings suggest that offspring of hypertensive parents have significantly higher plasma leptin levels and significantly lower hsLR concentrations compared with healthy offspring of healthy normotensive parents. Further studies are needed to determine the clinical significance of these observations.

Increased serum leptin concentrations in patients with chronic stable angina pectoris and ST-elevated myocardial infarction

Leptin is an adipocytokine that is produced mainly by adipose tissue; it is also identified in atherosclerotic lesions in human coronary atherosclerosis. However, the relation of serum leptin concentrations to ischemic heart disease (IHD) is still obscure. The aims of the present study were to investigate serum leptin concentrations in patients with ST-elevated myocardial infarction (STEMI) and with chronic stable angina pectoris (CSAP) and to evaluate the possible correlations of leptin to other atherosclerotic risk factors; including serum high sensitive C-reactive protein (Hs-CRP), serum homocysteine, and fibrinogen concentrations. For this purpose, 35 patients with CSAP, 40 with acute STEMI, and 30 control subjects with normal findings from coronary angiography were taken into the study prospectively. Serum leptin concentrations were significantly higher in patients with CSAP and STEMI compared to the control group (7.74 +/-1.34 vs 6.37 +/-1.85 ng/mL, p=0.021 and 8.22 +/-3.13 vs 6.37 +/-1.85 ng/mL, p=0.023, respectively). In addition, serum homocysteine concentrations were significantly increased in patients with CSAP (15.23 +/-5.96 vs 11.40 +/-2.11 micromol/L, p=0.025) and patients with STEMI (15.90 +/-5.02 vs 11.40 +/-2.11 micromol/L, p=0.012) compared to the control group. Serum fibrinogen concentrations were significantly increased only in the CSAP group as compared to controls (4.15 +/-1.39 vs 3.45 +/-1.19 g/L, p=0.025). No significant correlation was found between leptin levels and selected risk factors. In conclusion, serum leptin concentrations were significantly higher in both the CSAP and STEMI groups. However, owing to the lack of correlation between the leptin levels and selected classical coronary risk factors, it may be considered that leptin can be evaluated as one of the independent risk factors for IHD. Further randomized and controlled studies will be required to determine the pathophysiological meaning of the increased leptin levels and the central role between adipocyte function and atherosclerosis.

Insulin resistance, adipokines, and oxidative stress in nondiabetic, hypercholesterolemic patients: leptin as an 8-epi-prostaglandin F2alpha determinant

Limited data are available on the association of insulin resistance, adipokines, and in vivo lipid peroxidation. We investigated the relationships between insulin resistance, adipokines (leptin, adiponectin, and resistin), and oxidative stress in nondiabetic, hypercholesterolemic patients. Seventy-six nondiabetic patients with hypercholesterolemia participated in this cross-sectional study. Fasting glucose and insulin concentrations were analyzed. Serum leptin, adiponectin, and resistin concentrations and urinary excretion of 8-epi-prostaglandin F(2alpha) (8-epi-PGF(2alpha)) were determined using enzyme-linked immunosorbent assay. We divided all subjects into 3 groups, classified by the tertiles of homeostasis model assessment of insulin resistance (HOMA-IR) values, and clinical parameter comparisons were made among the 3 groups. The results showed that serum leptin (P < .001) and adiponectin levels (P < .05) were significantly different among the groups, although serum resistin was not different. Furthermore, the group with the highest HOMA-IR had a significantly higher urinary 8-epi-PGF(2alpha) excretion than the group with the lowest HOMA-IR (P = .017). Circulating leptin was positively correlated with urinary 8-epi-PGF(2alpha) (r = 0.323, P < .01) and HOMA-IR (r = 0.524, P < .001). Circulating adiponectin was negatively correlated with body mass index (r = -0.252, P < .05) and HOMA-IR (r = -0.228, P < .05). We could not find a relationship between circulating adiponectin or resistin and urinary 8-epi-PGF(2alpha) excretion. Stepwise multiple linear regression analysis showed that leptin was associated with the urinary 8-epi-PGF(2alpha) excretion after adjusting for age, sex, body mass index, blood lipids, and HOMA-IR (P = .002). In conclusion, our results show that more insulin-resistant state of nondiabetic, hypercholesterolemic patients is associated with decreased adiponectin and increased leptin and urinary 8-epi-PGF(2alpha) levels, although no relationship with resistin was observed. Furthermore, serum leptin independently contributed to urinary 8-epi-PGF(2alpha) excretion.

Cardiovascular death and the metabolic syndrome: role of adiposity-signaling hormones and inflammatory markers

OBJECTIVE

Levels of adiposity-signaling hormones and inflammatory markers are less favorable in individuals with the metabolic syndrome; their role in the association between the metabolic syndrome and cardiovascular mortality remains unclear.

RESEARCH DESIGN AND METHODS

We conducted a prospective study of 977 men and 1,141 women aged 40-94 years in 1984-1987, followed for mortality for a maximum of 20 years. Adiponectin, leptin, ghrelin, interleukin-6 (IL-6), C-reactive protein (CRP), and Adult Treatment Panel III-defined metabolic syndrome components were measured in fasting blood samples obtained in 1984-1987. Cox-proportional hazards models were used in survival analyses.

RESULTS

The age- and sex-adjusted hazard ratio (HR) (95% CI) for coronary heart disease (CHD) mortality associated with the metabolic syndrome was 1.65 (1.25-2.18) (P < 0.001); this association did not differ significantly by sex, age, or diabetic status (P > 0.2 for each interaction). The association between the metabolic syndrome and CHD mortality was not materially changed after adjustment for adiponectin, leptin, and ghrelin; it was attenuated by 25% after adjustment for IL-6 and 35% after adjustment for CRP. CHD mortality increased linearly with greater levels of IL-6 and CRP (P(trend) < 0.001 for each); the age- and sex-adjusted HRs comparing highest versus lowest quarter were 3.0 (1.87-4.89) for IL-6 and 2.1 (1.41-3.21) for CRP. IL-6, but not CRP, remained a significant predictor of CHD mortality in models including both inflammatory markers and the metabolic syndrome.

CONCLUSIONS

Adiposity-signaling hormones and inflammatory markers explain little to some of the association between the metabolic syndrome and CHD mortality. IL-6 levels predict CHD mortality independently of CRP.

Relationship of serum adiponectin and resistin to glucose intolerance and fat topography in South-Asians

OBJECTIVES

South-Asians have lower adiponectin levels compared to Caucasians. It was not clear however, if this intrinsic feature is related to aspects of glucose metabolism. This study aims to determine the relationship between body fat distribution and adipocytokine in South-Asian subjects by measuring serum adipocytokines, adiposity, insulinemia, and glucose tolerance levels.

METHODS

In this cross-sectional study, 150 South-Asians (80 males, 70 females) were included, 60 had NGT (Control group, Age 51.33 +/- 11.5, BMI 27 +/- 2.3), 60 had IGT (Age 57.7 +/- 12.5, BMI 27.2 +/- 2.7), 30 had type 2 DM (Age 49.5 +/- 10.9, BMI 28 +/- 1.7). Measures of adiposity, adipocytokines and other metabolic parameters were determined. Parameters were measured using the following: a) Plasma glucose by glucose oxidase method b) CRP by immunoturbidimetric method (Roche/Hitachi analyser) c) insulin by Medgenix INS-ELISA immunoenzymetric assay by Biosource (Belgium) d) Leptin, Adiponectin by radioimmunoassay kits by Linco Research (St. Charles MO) e) Resistin by immunoassay kits by Phoenix Pharmaceuticals INC (530 Harbor Boulevard, Belmont CA 94002, USA).

RESULTS

Adiponectin concentrations were highest in NGT, decreased in IGT and lowest in DMT2, (both p < 0.01). Leptin was significantly higher in DMT2 than IGT and NGT p = 0.02 and 0.04 respectively. There was a significant positive relationships between log adiponectin and 2-hr insulin values, p = 0.028 and history of hypertensions and a ischemic heart disease p = 0.008 with R = 0.65. There was a significant inverse correlation between log adiponectin and resistin, p < 0.01.

CONCLUSION

Resistin levels had an inverse correlation with adiponectin levels, indicating an inverse relationship between pro-inflammatory cytokines and adiponectin. Adiponectin levels were related to glucose tolerance.

Leptin and atherosclerosis

Leptin, a 167-amino acid peptide hormone produced by white adipose tissue, is primarily involved in the regulation of food intake and energy expenditure. Leptin receptors are expressed in many tissues including the cardiovascular system. Plasma leptin concentration is proportional to body adiposity and is markedly increased in obese individuals. Recent studies suggest that hyperleptinemia may play an important role in obesity-associated cardiovascular diseases including atherosclerosis. Leptin exerts many potentially atherogenic effects such as induction of endothelial dysfunction, stimulation of inflammatory reaction, oxidative stress, decrease in paraoxonase activity, platelet aggregation, migration, hypertrophy and proliferation of vascular smooth muscle cells. Leptin-deficient and leptin receptor-deficient mice are protected from arterial thrombosis and neointimal hyperplasia in response to arterial wall injury. Several clinical studies have demonstrated that high leptin level predicts acute cardiovascular events, restenosis after coronary angioplasty, and cerebral stroke independently of traditional risk factors. In addition, plasma leptin correlates with markers of subclinical atherosclerosis such as carotid artery intima-media thickness and coronary artery calcifications. Inhibition of leptin signaling may be a promising strategy to slow the progression of atherosclerosis in hyperleptinemic obese subjects.

Low plasma ghrelin concentration is an indicator of the metabolic syndrome

BACKGROUND

Low ghrelin concentration has been associated with several features of metabolic syndrome (MS), but the relationship between ghrelin concentration and MS as a cluster of metabolic aberrations has not yet been studied.

AIMS OF THE STUDY

To analyse whether ghrelin concentration is associated with MS.

RESEARCH DESIGN AND METHODS

Fasting plasma ghrelin concentrations of the population-based cohort of 1037 middle-aged men and women were analysed using a commercial radioimmunoassay kit (Phoenix Peptide). MS was determined using the new International Diabetes Federation criteria.

RESULTS

The prevalence of MS was 37.2%. The ghrelin concentrations were decreased in subjects with MS (635 pg/mL) compared to those without MS (687 pg/mL) (P=0.001). Ghrelin levels decreased with an increase in the number of metabolic abnormalities. Low ghrelin was a statistically significant predictor of MS in logistic regression analysis (P=0.005) so that the subjects in the 1st ghrelin quartile were at higher risk of having MS compared to the subjects in the 4th quartile (OR=1.82, 95% CI: 1.27-2.60, P=0.001). This association remained statistically significant after adjustment for age and sex (OR=1.76, 95% CI: 1.24-2.55, P=0.002).

CONCLUSIONS

Metabolic syndrome is associated with low ghrelin levels suggesting a relationship of ghrelin in the metabolic disturbances of MS.

Leptin is not associated independently with hypertension in Japanese-Brazilian women

We evaluated the relationship of leptin with hypertension adjusted for body mass index (BMI) and/or waist circumference in a population of Japanese-Brazilian women aged > or = 30 years with centrally distributed adiposity. After excluding diabetic subjects, the study subjects--who participated in a population-based study on the prevalence of metabolic syndrome--showed prevalence rates of obesity (BMI > or = 25 kg/m2) and central adiposity (waist > or = 80 cm) of 32.0 and 37.8%, respectively. The hypertensive group (N = 162) was older, had higher BMI (24.9 +/- 4.2 vs 23.3 +/- 3.4 kg/m2, P < 0.001), waist circumference (81.1 +/- 10.1 vs 76.3 +/- 8.2 cm, P < 0.001) and insulin levels (8.0 +/- 6.2 vs 7.1 +/- 4.9 microU/mL, P < 0.05) than the normotensive group (N = 322) and showed an unfavorable metabolic profile (higher 2-h plasma glucose, C-reactive protein and non-HDL cholesterol levels). Leptin did not differ between groups (8.2 +/- 6.8 vs 7.2 +/- 6.6 ng/mL, P = 0.09, for hypertensive vs normotensive, respectively) and its levels correlated significantly with anthropometric variables but not with blood pressure. Logistic regression analysis indicated that age and waist were independently associated with hypertension but not with homeostasis model assessment of insulin resistance or leptin levels. The lack of an independent association of hypertension with metabolic parameters (2-h glucose, C-reactive protein and non-HDL cholesterol) after adjustment for central adiposity suggested that visceral fat deposition may be the common mediator of the disturbances of the metabolic syndrome. Our data indicate that age and waist are major determinants of hypertension in this population of centrally obese (waist > or = 80 cm) Japanese-Brazilian women, but do not support a role for leptin in the elevation of blood pressure.

A Positive Association between Leptin and Blood Pressure of Normal Range in Japanese Men

The results of previous studies on the relationship between leptin and blood pressure are discordant. We investigated to what extent the serum leptin level was related to blood pressure independent of the degree of insulin resistance. The subjects were 1916 men aged 34-69 years whose mean body mass index (BMI) was 23.0 kg/m2. Blood pressure was regressed by leptin concentrations with adjustments for age, BMI, insulin resistance, triglyceride, high density lipoprotein cholesterol, low density lipoprotein cholesterol, physical activity, drinking habits and smoking status. Leptin was associated with diastolic blood pressure (DBP) (standardized beta: 0.092, p = 0.003), but not with systolic blood pressure (SBP) (standardized beta: 0.035, p = 0.25), although insulin resistance was positively associated with both SBP and DBP (standardized beta: 0.175 for SBP, p < 0.001 and 0.114 for DBP, p < 0.001) among all subjects. After subjects were divided into those with normal blood pressure (SBP <130 mmHg and DBP <85 mmHg) and those with higher blood pressure, leptin was positively and significantly associated with DBP (standardized beta: 0.106, p = 0.012) independent of the degree of insulin resistance, but not with SBP (standardized beta: 0.064, p = 0.13) among subjects in the normal blood pressure range. Among the subjects with higher blood pressure, however, neither the association of leptin with SBP nor that of leptin with DBP was statistically significant. These findings suggest that leptin may maintain and increase arterial tone, resulting in the elevation of DBP only within normal blood pressure range. It is also likely that leptin is a physiological mediator--or at least a marker--of some degree of DBP elevation in obesity.

Hyperhomocysteinemia correlates with insulin resistance and low-grade systemic inflammation in obese prepubertal children

Obesity is an independent risk factor for the development of cardiovascular disease frequently associated with hypertension, dyslipemia, diabetes, and insulin resistance. Higher homocysteine (Hcy) levels are observed in the hyperinsulinemic obese adults and suggest that Hcy could play a role in the higher risk of cardiovascular disease in obesity. We analyzed total Hcy levels in obese prepubertal children and their possible association with both metabolic syndrome and various inflammatory biomarkers and leptin. We studied 43 obese children (aged 6-9 years) and an equal number of nonobese children, paired by age and sex. The obese subjects presented significantly elevated values for insulin (P = .003), C-reactive protein (P = .033), and leptin (P < .001). No significant differences were found in Hcy levels between the obese and nonobese children. However, Hcy concentration was significantly higher in the hyperinsulinemic obese children than in the normoinsulinemic group (P = .002). Using multivariant regression analysis, in the obese group, corrected for age and sex, the homeostasis model assessment for insulin resistance (P partial = .001) and leptin (P partial = .02) are independent predictive factors for Hcy. In the control group, corrected for age and sex, the homeostasis model assessment for insulin resistance (P partial = .005) and leptin (P partial = .031) also are independent predictive factor for Hcy. Increased plasma Hcy, particularly in hyperinsulinemic obese children, may be causally involved in the pathogenesis of atherosclerosis and/or cardiovascular disease, both of which are common in obesity.

Leptin levels in obese women with and without type 2 diabetes mellitus

INTRODUCTION

The role of leptin has been more clear in the endocrinology area after the discovery of its secretion from the adipose tissue. The aim of the study is to investigate the leptin levels in obese women in whom type 2 diabetes mellitus were present or absent.

MATERIALS AND METHODS

Thirty-five obese women with type 2 diabetes mellitus (group 1) and 34 obese women without type 2 diabetes mellitus (group 2) were enrolled in the study. In both groups the body mass index (BMI), waist circumference, and waist-to-hip ratio were measured. Leptin, HbA1c, creatinine and the lipid profile were assessed.

RESULTS

Leptin was found to be statistically significantly lower in group 1 than in group 2 (40.22 +/- 17.77 ng/ml versus 50.12 +/- 15.51 ng/ml, respectively; p = 0.019). It was well correlated with BMI in group 1 (r = 0.60, p = 0.0001). In group 1 also, correlation of leptin was moderate with creatinine and high-density lipoprotein-cholesterol (r = 0.36, p = 0.037 versus r = 0.37, p = 0.027, respectively), whereas triglyceride had a negative correlation (r = -0.34, p = 0.046). In group 2, the only significant correlation with leptin was BMI (r = 0.41, p = 0.02). Leptin was also significantly lower in 17 subjects with poorly controlled diabetes mellitus than in 18 well-controlled diabetics (33.54 +/- 15.82 ng/ml versus 44.61 +/- 17.54 ng/ml, respectively; p = 0.038).

CONCLUSION

Since leptin is lower in obese women with diabetes than without diabetes and additionally it is even lower in the poorly controlled diabetes subgroup, we think that further studies a rerequired to make clear the issue for lower leptin levels, whether it is a reason or an outcome.

Leptin levels in obese women with and without type 2 diabetes mellitus

INTRODUCTION: The role of leptin has been more clear in the endocrinology area after the discovery of its secretion from the adipose tissue. The aim of the study is to investigate the leptin levels in obese women in whom type 2 diabetes mellitus were present or absent. MATERIALS AND METHODS: Thirty-five obese women with type 2 diabetes mellitus (group 1) and 34 obese women without type 2 diabetes mellitus (group 2) were enrolled in the study. In both groups the body mass index (BMI), waist circumference, and waist-to-hip ratio were measured. Leptin, HbA1c, creatinine and the lipid profile were assessed. RESULTS: Leptin was found to be statistically significantly lower in group 1 than in group 2 (40.22 +/- 17.77 ng/ml versus 50.12 +/- 15.51 ng/ml, respectively; p = 0.019). It was well correlated with BMI in group 1 (r = 0.60, p = 0.0001). In group 1 also, correlation of leptin was moderate with creatinine and high-density lipoprotein-cholesterol (r = 0.36, p = 0.037 versus r = 0.37, p = 0.027, respectively), whereas triglyceride had a negative correlation (r = -0.34, p = 0.046). In group 2, the only significant correlation with leptin was BMI (r = 0.41, p = 0.02). Leptin was also significantly lower in 17 subjects with poorly controlled diabetes mellitus than in 18 well-controlled diabetics (33.54 +/- 15.82 ng/ml versus 44.61 +/- 17.54 ng/ml, respectively; p = 0.038). CONCLUSION: Since leptin is lower in obese women with diabetes than without diabetes and additionally it is even lower in the poorly controlled diabetes subgroup, we think that further studies a rerequired to make clear the issue for lower leptin levels, whether it is a reason or an outcome.