Increased leptin/adiponectin ratio and free leptin index are markers of insulin resistance in obese girls during pubertal development

The associations of leptin and adiponectin with the metabolic syndrome in an Indonesian and a Dutch population

BACKGROUND AND AIMS

At the same BMI, Asian populations develop cardiometabolic complications earlier than Western populations. We hypothesized that a different secretion of the adipocyte-derived hormones leptin and adiponectin plays a role and investigated the associations of the two hormones with the metabolic syndrome (MetS) in an Indonesian and a Dutch population.

METHODS AND RESULTS

We performed cross-sectional analyses of the Netherlands Epidemiology of Obesity Study (n = 6602) and the SUGAR Scientific Programme Indonesia-Netherlands Study (n = 1461). We examined sex-stratified associations of leptin and adiponectin with MetS, using multivariate logistic regression including adjustment for total body fat. The mean (SD) leptin (mcg/L) were 4.7 (6.0) in Indonesian men, 18.6 (12.0) in Indonesian women, 9.1 (7.7) in Dutch men, and 23.4 (17.4) in Dutch women. The mean (SD) adiponectin (mg/L) were 5.7 (5.4), 7.5 (7.1), 6.6 (3.3), and 11.3 (4.9), respectively. Within the same BMI category, leptin concentrations were similar in the two populations, whereas adiponectin was lower in the Indonesian population. Per SD of leptin, adjusted prevalence odds ratios (ORs, 95%CI) of MetS were 0.9 (0.6-1.2) in Indonesian men, 1.1 (0.9-1.4) in Indonesian women, 2.2 (1.6-2.8) in Dutch men, and 1.2 (1.0-1.5) in Dutch women. Per SD of adiponectin, the ORs were 0.9 (0.7-1.2), 0.8 (0.7-1.0), 0.6 (0.6-0.8), and 0.4 (0.4-0.5), respectively.

CONCLUSIONS

Despite lower adiponectin levels, adiponectin was not related to the MetS in the Indonesian population and can not explain their increased cardiometabolic risk at the same BMI.

Analysis of probable lipotoxic damage and myocardial fibrosis in epicardial obesity

Myocardial fibrosis is considered a key pathological process in the development of cardiovascular diseases. In epicardial obesity (EO), the main cause of fibrosis development is lipotoxic myocardial damage. It is important to detect myocardial fibrosis at an early stage, using non-invasive diagnostic methods. According to the results of echocardiography (ECG), 110 men with general obesity were divided into the following two groups: Group I with epicardial fat thickness (tEAT) ≥ 7 mm (n = 70) and Group II with tEAT < 7 mm (n = 40) without diastolic dysfunction. The levels of metabolic factors, pro-inflammatory cytokines, adipokines, and free fatty acids (FFA), profibrotic markers were determined in both groups. In Group I, the level of interleukin (IL)-6, C-reactive protein, and tumor necrosis factor (TNF)-α increased and that of leptin and adiponectin decreased compared with those in Group II. There was an increase in the level of all studied profibrotic factors in Group I. The level of TNF-α and IL-6 showed a positive correlation with the level of leptin and FFA and a negative correlation with the level of adiponectin. We also observed a relationship between the level of collagen, transforming growth factor (TGF)-β, and metalloproteinase (MMP)-3 and EO. Our results showed that confirmed EO correlates with not only disadipocytosis and increased levels of pro-inflammatory cytokines, but also increased levels of profibrotic factors. This suggests that the studied markers of fibrosis may be used to determine preclinical cardiac fibrosis with lipotoxic myocardial damage in patients with EO.

Is "Leptin Resistance" Another Key Resistance to Manage Type 2 Diabetes?

Although novel pharmacological options for the treatment of type 2 diabetes mellitus (DM2) have been observed to modulate the functionality of several key organs in glucose homeostasis, successful regulation of insulin resistance (IR), body weight management, and pharmacological treatment of obesity remain notable problems in endocrinology. Leptin may be a pivotal player in this scenario, as an adipokine which centrally regulates appetite and energy balance. In obesity, excessive caloric intake promotes a low-grade inflammatory response, which leads to dysregulations in lipid storage and adipokine secretion. In turn, these entail alterations in leptin sensitivity, leptin transport across the blood-brain barrier and defects in post-receptor signaling. Furthermore, hypothalamic inflammation and endoplasmic reticulum stress may increase the expression of molecules which may disrupt leptin signaling. Abundant evidence has linked obesity and leptin resistance, which may precede or occur simultaneously to IR and DM2. Thus, leptin sensitivity may be a potential early therapeutic target that demands further preclinical and clinical research. Modulators of insulin sensitivity have been tested in animal models and small clinical trials with promising results, especially in combination with agents such as amylin and GLP-1 analogs, in particular, due to their central activity in the hypothalamus.

Adipocytes Directly Affect Coronary Artery Disease Pathogenesis via Induction of Adipokine and Cytokine Imbalances

This study aimed to investigate the adipokine and cytokine profiles of adipocytes from epicardial and subcutaneous adipose tissues in interconnection with the visceral adipose tissue area and the biochemical and clinical characteristics of patients with coronary artery disease. We assessed 84 patients with coronary artery disease (65 men, 19 women) and divided them into two groups based on the presence of visceral obesity. We sampled epicardial and subcutaneous adipose tissues from the patients with visceral obesity. We then cultured the adipocytes and evaluated their adipokine profiles and pro-inflammatory activity. Results show that the mRNA expression of adiponectin in cultures of epicardial adipocytes from patients with and without visceral obesity was lower than that in subcutaneous adipocytes. Moreover, adiponectin mRNA expression in cultures of subcutaneous and epicardial adipocytes from patients with visceral obesity was lower than that in patients without obesity. For leptin, the reverse pattern was observed, with expression higher in cultures of epicardial adipocytes than in subcutaneous adipocytes and higher in epicardial adipocytes from patients with visceral obesity than in those from subjects without visceral obesity. In addition, in epicardial adipocytes, increased expression of proinflammatory cytokine genes (IL6, TNF) was observed compared with that in subcutaneous adipocytes. In contrast, expression of IL10 was higher in cultures of subcutaneous adipocytes than in epicardial adipocytes. The epicardial adipose tissue area was associated with the presence of higher levels of leptin and TNF-α within adipocytes and serum, increased lipid and carbohydrate metabolism. Coronary artery disease, in the context of the status of epicardial adipocytes, can be characterized as “metabolic inflammation,” suggesting the direct involvement of adipocytes in pathogenesis through the development of adipokine imbalances and activation of proinflammatory processes.

Influence of visceral obesity on the secretion of adipokines with epicardial adipocytes in patients with coronary heart disease

Aim. To study adipokine-cytokine profile of epicardial adipocytes (EAT) and subcutaneous adipose tissue (SAT) in conjunction with the area of visceral adipose tissue (VAT), biochemical and clinical characteristics of patients with coronary heart disease. Materials and methods. Examined 84 patients (70 men and 14 women) with coronary artery disease. In fact the presence of visceral obesity (VO) the patients were divided into two groups. Patients VO the sampling of adipocytes of EAT and SAT, with subsequent cultivation and evaluation of adipokine and provospalitelna activity. Carried out the determination of carbohydrate and lipid metabolism, adipokine and pro-inflammatory status in the blood serum. Results and discussion. It was found that adipokine-cytokine profile of adipocytes of EAT and SAT differ. Adipocytes art of the disease on the background characterized by an increase IL-1, TNF-α, leptin-adiponectin relationships and a decrease in the content of protective factors: adiponectin and anti-inflammatory cytokine IL-10. While the SAT adipocytes was characterized by a decrease in the concentration of soluble receptor for leptin and the more pronounced leptinresistance, and the increase in proinflammatory cytokines was offset by the increase in the concentration of IL-10. The presence associated with multi-vessel coronary bed lesion, multifocal atherosclerosis, insulin resistance, atherogenic dyslipidemia, an imbalance of adipokines and markers of inflammation. So the value of the square VAT determined higher concentrations of leptin, TNF-α in adipocytes and serum, lipid and carbohydrate metabolism and a lower content of soluble receptor for leptin. Conclusion. Thus, the disease on the background of the status of the adipocytes of EAT characterized as a "metabolic inflammation", and may indicate the direct involvement of adipocytes in the pathogenesis of coronary artery disease, due to the formation of adipokine imbalance and the activation of proinflammatory reactions.

Association of adiponectin/leptin ratio with carbohydrate and lipid metabolism parameters in HIV-infected patients during antiretroviral therapy

BACKGROUND

Adiponectin and leptin are adipose tissue hormones that regulate important lipid and glucose metabolic pathways. Our objective was to evaluate the interplay of these hormones described by the adiponectin/leptin ratio (ALR) in correlation to lipid and carbohydrate metabolism parameters in nondiabetic HIV-infected patients during antiretroviral therapy (ART).

MATERIALS AND METHODS

We enrolled consecutive nondiabetic patients with confirmed HIV infection, undergoing stable ART regimens for at least six months. Blood samples were collected and tested for immunological and virological parameters, adiponectin and leptin, fasting insulin, fasting plasma glucose, fasting triglycerides, total cholesterol, LDL cholesterol, and HDL cholesterol. ALR was computed for each patient. Resistance to insulin was assessed by calculating the Quantitative Insulin Sensitivity Check Index (QUICKI).

RESULTS

We enrolled 87 HIV-infected persons, with a mean age of 31.7 years (range: 18-65), including 47 men (mean age = 32.8 years) and 40 women (mean age = 30.5 years). The median value of ALR was 6.8 (interquartile range - IQR = 17.1). In male patients, ALR was inversely associated with the serum level of triglycerides (R = 0.285, p = 0.05), total cholesterol (R = 0.326, p = 0.02), and LDL cholesterol (R = 0.298, p = 0.04). Also for the male cohort, an increase in ALR seemed to improve insulin sensitivity (R = 0.323, p = 0.02) and serum HDL cholesterol (R = 0.597, p = 0.01). None of these correlations were observed in HIV-infected women.

CONCLUSION

Adiponectin and leptin seem to play important but different gender-specific roles in the pathogenesis of lipid and glucose metabolism of HIV-infected patients undergoing antiretroviral therapy.

ABBREVIATIONS

ALR, adiponectin/leptin ratio; BMI, body mass index; LDL, low-density lipoprotein; HDL, high-density lipoprotein; QUICKI, Quantitative Insulin Sensitivity Check Index.

Neonatal Overnutrition Increases Testicular Size and Expression of Luteinizing Hormone β-Subunit in Peripubertal Male Rats

Proper nutrition is important for growth and development. Maturation of the reproductive axis and the timing of pubertal onset can be delayed when insufficient nutrition is available, or possibly advanced with nutritional abundance. The childhood obesity epidemic has been linked to a secular trend in advanced puberty in some populations. The increase in circulating leptin that occurs in association with obesity has been suggested to act as a signal that an adequate nutritional status exists for puberty to occur, allowing activation of central mechanisms. However, obesity-associated hyperleptinemia is linked to decreased leptin sensitivity, at least in adults. Here, we analyzed whether neonatal overnutrition modifies the response to an increase in leptin in peripubertal male rats, as previously demonstrated in females. Wistar rats were raised in litters of 4 (neonatal overnutrition) or 12 pups (controls) per dam. Leptin was administered sc (3 µg/g body weight) at postnatal day 35 and the rats killed 45 min or 2 h later. Postnatal overfeeding resulted in increased body weight and circulating leptin levels; however, we found no overweight-related changes in the mRNA levels of neuropeptides involved in metabolism or reproduction. In contrast, pituitary expression of luteinizing hormone (LH) beta-subunit was increased in overweight rats, as was testicular weight. There were no basal differences between L4 and L12 males or in their response to leptin administration in pSTAT3 levels in the hypothalamus at either 45 min or 2 h. In contrast, pJAK2 was found to be higher at 45 min in L4 compared to L12 males regardless of leptin treatment, while at 2 h it was higher in L4 leptin-treated males compared to L12 leptin-treated males, as well as L4 vehicle-treated rats. There were no changes in response to leptin administration in the expression of the neuropeptides analyzed. However, serum LH levels rose only in L4 males in response to leptin, but with no change in testosterone levels. In conclusion, the advancement in pubertal onset in males with neonatal overnutrition does not appear to be related to overt modifications in the central response to exogenous leptin during the peripubertal period.

Analysis of the association of leptin and adiponectin concentrations with metabolic syndrome in children: Results from the IDEFICS study

BACKGROUND AND AIMS

Adipokines may play a role in the pathogenesis of the metabolic syndrome (MetS) in children. We aimed to evaluate the association of leptin, adiponectin, and its ratio (L/A ratio) with the metabolic syndrome (MetS) in a subsample of the IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS) cohort.

METHODS AND RESULTS

Leptin, adiponectin and MetS parameters were measured in a subsample of 1253 children (3-9.9 years) participating to the IDEFICS study, grouped as: Non-OW (underweight/normal weight) and OW/Ob (overweight/obese). MetS was defined using the sex- and age-specific cut-offs based on the distribution of MetS components in the IDEFICS cohort. The prevalence of the MetS among OW/Ob was 24.8% and 27.1% in boys and girls respectively, whereas ≤2% among Non-OW. OW/Ob had significantly higher leptin and L/A ratio as compared to Non-OW. Significantly higher leptin was found in OW/Ob with MetS as compared with OW/Ob without MetS. Significantly lower adiponectin was observed only in OW/Ob girls as compared to Non-OW. A 1SD increase in leptin and L/A ratio z-scores or a 1SD decrease in adiponectin z-score were significantly associated with higher risk of MetS. After adjustment for BMI or body fat mass (BFM) the association remained significant only for leptin.

CONCLUSION

We showed that in European children, higher leptin concentration is associated with MetS, even after adjusting for BMI or BFM, confirming an early role of leptin in MetS, while the association of adiponectin with MetS seems be mediated by body fat in this age range.

Comparison between body mass index and a body shape index with adiponectin/leptin ratio and markers of glucose metabolism among adolescents

BACKGROUND

Besides body mass index (BMI), new parameters have been developed to classify individual body shape.

AIM

To investigate the relationship between BMI, waist circumference (WC), a body shape index (ABSI) and ABSI-adolescents among adolescents and verify which would better predict lower adiponectin/leptin (A/L) ratio and disturbances on glucose metabolism.

SUBJECTS AND METHODS

A cross-sectional study with 197 Brazilian adolescents of 14-18 years. Serum leptin, adiponectin, glucose and insulin were measured. A/L ratio, ABSI, ABSI-adolescents, BMI, homeostasis model assessment estimates of insulin resistance (HOMA-IR) and β-cell function (HOMA-β) and the quantitative insulin sensitivity check index (QUICKI) were calculated.

RESULTS

ABSI-adolescents positively correlated with WC (r = 0.83, p < 0.0001) and BMI (r = 0.66, p < 0.0001), but stronger correlations were observed between WC and BMI (r = 0.95, p < 0.0001). ABSI-adolescents, BMI and WC negatively correlated with A/L ratio (all p < 0.0001). The correlation between BMI and A/L ratio was the strongest (r = -0.63, p < 0.001). A/L ratio, BMI, WC and ABSI-adolescents correlated with markers of glucose metabolism (all p < 0.0001) and the strongest correlation was observed with BMI (QUICKI: r = -0.75; HOMA-IR: r = 0.76; HOMA-β: r = 0.77; insulin: r = 0.79). Associations were confirmed by linear regression analysis, adjusted for sex and age.

CONCLUSIONS

ABSI-adolescents, but not ABSI, was related to A/L ratio and to markers of glucose metabolism, but not more strongly than BMI and WC.

Comparisons of physical activity, adipokines, vitamin D status and dietary vitamin D intake among adolescents

BACKGROUND

Considering that lifestyle and diet are key factors responsible for the increases in adiposity in youth, it is important to understand how vitamin D, adipokines and markers of glucose metabolism are related to physical activity level (PAL) during growth. The present study aimed to investigate associations between physical activity level, adiponectin/leptin ratio, vitamin D status and dietary vitamin D intake among adolescents.

METHODS

A cross-sectional study was conducted with adolescents aged 14-18 years old who were living in São Paulo, Brazil. Serum 25 hydroxyvitamin D [25(OH)D], adiponectin (A), leptin (L), glucose and insulin were obtained after 12 h of fasting. Dietary calcium and vitamin D intake were measured by 24-h food record, as repeated in 62.6% of the sample. PAL was measured by the International Physical Activity Questionnaire (IPAQ). Pearson's chi-square test, Pearson correlation and linear regression analysis were performed.

RESULTS

A total of 198 subjects, mean (SD) age 16.3 (1.4) years, 51% male, were enrolled in the study. Some 9% of participants were sedentary, 22% were insufficiently active (IA), 51% were active and 18% were very active (VA). The A/L ratio was lower among sedentary/IA subjects [2.2 (4.0) versus 5.6 (12.3); P = 0.01] compared to active/VA subjects. PAL was not associated with vitamin D status or markers of glucose metabolism. Serum 25(OH)D positively associated with vitamin D intake, after adjusting for sex, sun exposure and season of the year in regression analysis (partial r² =0.026, P = 0.02).

CONCLUSIONS

Low PAL was associated with a lower A/L ratio. Vitamin D status was not associated with sun exposure habits, although it was positively correlated with vitamin D intake.

Association between insulin resistance and estrogen in sexual precocity of obese children

The aim of the study was to examine the association between sexual precocity and high-molecular weight (HMW)-adiponectin and investigate the correlation of insulin resistance and estrogen levels in obese children. In total, 60 obese children (30 boys and 30 girls) with sexual precocity were included in group A, 60 obese children (30 boys and 30 girls) without sexual precocity were included in group B, and 60 average weight children (30 boys and 30 girls) were included in group C. The levels of HMW adiponectin, fasting blood glucose, fasting insulin, luteinizing hormone (LH) peak, estradiol and testosterone were measured. The results showed that the HMW-adiponectin level of group A was the lowest and that of group C was the highest. The difference was statistically significant (P<0.05). The homeostasis model assessment of insulin resistance (HOMA-IR) and estradiol levels of group A were significantly higher than those of group B, and group B was higher than that of group C. LH peak and testosterone levels of group A were the lowest while those of group C were the highest. The differences were statistically significant (P<0.05). A subgroup analysis showed that the above results were more significant in girls. The Pearson correlation analysis revealed that the level of HMW-adiponectin was negatively correlated with HOMA-IR and estradiol (P<0.05), and positively correlated with the LH peak (P<0.05). In conclusion, sexual precocity of obese children may be associated with insulin resistance, and the link may be HMW-adiponectin.

Weight Gain in Infancy and Overweight or Obesity in Childhood across the Gestational Spectrum: a Prospective Birth Cohort Study

This study aimed to investigate the optimal degree of weight gain across the gestational spectrum in 1971 children enrolled at birth and followed up to age 7 years. Weight gain in infancy was categorized into four groups based on weight gain z-scores: slow (<-0.67), on track (-0.67 to 0.67), rapid (0.67 to 1.28), and extremely rapid (>1.28). Underweight and overweight or obesity (OWO) were defined as a body mass index ≤5(th) and ≥85(th) percentile, respectively, for age and gender. In our population, OWO was far more common than underweight (39.7% vs. 3.6%). Weight gain tracked strongly from age 4 to 24 months, and was positively associated with OWO and an unfavorable pattern of metabolic biomarkers, although the degree of weight gain for the risk was different across gestational categories. Extremely rapid weight gain led to a particularly high risk of OWO among children born early term and late preterm: odds ratio: 3.3 (95% confidence interval: 1.9 to 5.5) and 3.7 (1.8 to 7.5), respectively, as compared to those with on track weight gain. Our findings suggest that monitoring and ensuring optimal weight gain across the entire gestational spectrum beginning from birth represents a first step towards primary prevention of childhood obesity.

Diabetic and dyslipidaemic morbidly obese exhibit more liver alterations compared with healthy morbidly obese

Background & aims

To study the origin of fat excess in the livers of morbidly obese (MO) individuals, we analysed lipids and lipases in both plasma and liver and genes involved in lipid transport, or related with, in that organ.

Methods

Thirty-two MO patients were grouped according to the absence (healthy: DM − DL −) or presence of comorbidities (dyslipidemic: DM − DL +; or dyslipidemic with type 2 diabetes: DM + DL +) before and one year after gastric bypass.

Results

The livers of healthy, DL and DM patients contained more lipids (9.8, 9.5 and 13.7 times, respectively) than those of control subjects. The genes implicated in liver lipid uptake, including HL, LPL, VLDLr, and FAT/CD36, showed increased expression compared with the controls. The expression of genes involved in lipid-related processes outside of the liver, such as apoB, PPARα and PGC1α, CYP7a1 and HMGCR, was reduced in these patients compared with the controls. PAI1 and TNFα gene expression in the diabetic livers was increased compared with the other obese groups and control group. Increased steatosis and fibrosis were also noted in the MO individuals.

Conclusions

Hepatic lipid parameters in MO patients change based on their comorbidities. The gene expression and lipid levels after bariatric surgery were less prominent in the diabetic patients. Lipid receptor overexpression could enable the liver to capture circulating lipids, thus favouring the steatosis typically observed in diabetic and dyslipidaemic MO individuals.

•

The criteria used to define the “metabolically healthy” obese is not applicable to morbidly obese patients.

•

Virtually no studies of how bariatric surgery affects depending on comorbidities and less how affect to the liver.

•

Anthropometrics, fat, lipid profile and inflammation parameters are different depending of comorbidities, not only in plasma but also in liver.

•

The extent of lipases and lipids in the liver biopsies could help not only the diagnosis but also to follow the course of recovery after surgery.

•

The morbidly obese individuals with diabetes and dyslipidemia have more altered metabolic profiles than the other two groups.

Elevated serum leptin, adiponectin and leptin to adiponectin ratio is associated with chronic kidney disease in Asian adults

Background

Adiponectin and leptin, two of the key cytokines secreted by adipocytes, have been shown to be associated with cardiovascular disease. However, the association of these adipocytokines with chronic kidney disease (CKD) is not clear. We examined the association of serum adiponectin, leptin levels and leptin to adiponectin ratio (LAR) with CKD in a population-based sample of Asian adults.

Methods

We conducted a case-control study (450 CKD cases and 920 controls matched for age, sex and ethnicity) involving Chinese and Indian adults aged 40–80 years who participated in the Singapore Epidemiology of Eye Diseases Study (2007–2011). CKD was defined as an estimated glomerular filtration rate <60 mL/min/1.73m² from serum creatinine. Serum adiponectin and leptin levels were measured using commercially available ELISA. Odds ratio of CKD associated with elevated adiponectin and leptin levels were estimated using logistic regression models adjusted for age, gender, ethnicity, education, smoking, body mass index, diabetes, blood pressure, total and HDL cholesterol.

Results

CKD cases had higher levels of leptin (mean [SD] 9.7 [11.5] vs.16.9 [20.2] ng/mL, p<0.0001) and adiponectin (10.4 [7.4] vs. 9.2 [4.2], p = 0.001) compared to controls. In multi-variable models, compared to those in the lowest quartile, the OR (95% confidence interval) of CKD among those in the highest quartile were: 6.46 (3.84, 10.88), 1.94 (1.32–2.85) and 2.88 (1.78–4.64) for leptin, adiponectin and LAR. Similar associations were also observed when adiponectin and leptin were analyzed as continuous variables. This positive association of serum adiponectin, leptin and LAR with CKD was consistently present in subgroups of gender, ethnicity, diabetes, hypertension and overweight status (all P-interaction >0.1).

Conclusions

Higher levels of serum adiponectin, leptin and LAR were positively associated with CKD independent of traditional risk factors in this Asian population.

The relation of leptin and soluble leptin receptor levels with metabolic and clinical parameters in obese and healthy children

We investigated the relation of serum leptin, soluble leptin receptor (sLR) and free leptin index (FLI) with metabolic and anthropometric parameters in obese and healthy children. Height, weight, waist circumference (WC), fasting serum glucose, insulin, lipid profile, leptin and sLR levels of 35 obese children and 36 healthy children were measured and FLI was calculated as the ratio of leptin to sLR. In obese children, serum leptin and FLI were found significantly higher, while sLR level was significantly lower than the healthy children. Comparison of obese children regarding the insulin resistance showed significantly higher serum leptin and FLI in the insulin resistant group; however sLR level was not different between the insulin resistant and non-resistant obese children. In obese children, sLR was not correlated with any of the metabolic parameters except total cholesterol, while FLI was significantly and positively correlated with BMI, WC, TC, fasting insulin, and HOMA-IR. However, regression analysis confirmed that the HOMA-IR was the only independent variable significantly correlated with FLI in obese children. Findings of this study suggest that in obese children and adolescents (i) serum leptin and FLI were found significantly higher, while sLR level was significantly lower than the healthy children, (ii) increased FLI might be a compensatory mechanism for increasing leptin effect in peripheral tissue, (iii) FLI is a more accurate marker to evaluate leptin resistance than leptin or sLR alone, and (iv) increased FLI may contribute toward the development of hyperinsulinemia and insulin resistance.