Leptin: a review of its peripheral actions and interactions

Calorie restriction-induced leptin reduction and T-lymphocyte activation in blood and adipose tissue in men with overweight and obesity

BACKGROUND

T-Lymphocyte activation is modulated by the adipokine leptin and serum concentrations of this hormone can be reduced with short-term calorie restriction. The aim of this study was to understand whether leptin per se is important in determining levels of T-lymphocyte activation in humans, by investigating whether the reduction in leptin concentration following calorie restriction is associated with a decrease in T-Lymphocyte activation in blood and adipose tissue.

METHODS

Twelve men with overweight and obesity (age 35-55 years, waist circumference 95-115 cm) reduced their calorie intake by 50% for 3 consecutive days. Blood and subcutaneous adipose tissue were obtained for isolation of immune cells and cytokine analysis. CD4+ and CD8 + T-Lymphocytes were identified and characterised according to their expression of activation markers CD25 and CD69 by flow cytometry.

RESULTS

Serum leptin was reduced by (mean ± SEM) 31 ± 16% (p < 0.001) following calorie restriction. The percentage of blood CD4 + CD25 + T-lymphocytes and level of CD25 expression on these lymphocytes were significantly reduced by 8 ± 10% (p = 0.016) and 8 ± 4% (p = 0.058), respectively. After calorie restriction, ex vivo leptin secretion from abdominal subcutaneous adipose tissue explants was not changed, and this corresponded with a lack of change in adipose tissue resident T-Lymphocyte activation.

CONCLUSIONS

Serum leptin was reduced after calorie restriction and this was temporally associated with a reduction in activation of blood CD4 + CD25 + T-Lymphocytes. In abdominal subcutaneous adipose tissue, however, leptin secretion was unaltered, and there were no observed changes in adipose resident T-Lymphocyte activation.

Involvement of ObRb receptor, Nitric oxide, and BKCa channel signaling pathways in leptin-induced relaxation of pregnant mouse uterus

The purpose of this study was to determine the receptor subtype and the underlying mechanisms involved in the relaxant effect to leptin in mid- and late-pregnant mouse uterus. We determined the relative mRNA expression of receptor subtypes, eNOS, and BKCa channel by quantitative PCR and also the overall receptor expression by immunohistochemistry. Isometric tension studies were conducted to evaluate the effects of leptin and to delineate its mechanisms. A selective siRNA for the ObRb receptor was used to determine the participation of the receptor subtype in biochemical and molecular effects of leptin. The relaxant response to leptin was greater in mid-pregnancy compared to late pregnancy and was mediated by the activation of BKCa channels by eNOS-derived nitric oxide in an ObRb receptor-dependent manner. In comparison to mid-pregnancy, expression of short forms (mainly ObRa receptor) of the receptor was significantly increased in late pregnancy, whereas ObRb receptor expression was similar in both phases. The results of the study suggest that ObRb receptor mediates leptin-induced increase in eNOS expression and NO synthesis. Leptin-induced eNOS expression and activation cause cGMP-independent stimulation of BKCa channels causing uterine relaxation. Increased short forms of the receptors and reduced BKCa channels exert a negative effect on uterine relaxation in late pregnancy. Leptin may have a physiological role in maintaining uterine quiescence in mid-pregnancy and its reduced relaxant response in late gestation may facilitate labor. Further, ObRb receptor agonists may be useful in the management of preterm labor.

JPT2 in subclinical hypothyroidism-related miscarriage as a transcription co-factor: involvement of LEPR/STAT3 activation

BACKGROUND AND PURPOSE

Subclinical hypothyroidism (SCH) has been identified to be associated with implantation failure, in which the dysfunction of trophoblast cells is involved. In this study, the transcriptomics of aborted placenta from SCH rats were analyzed. Jupiter microtubule-associated homolog 2 (JPT2) was downregulated in the aborted placenta. This study aims to investigate its role in SCH-associated miscarriage.

METHODS

Spontaneous abortion was observed in SCH rats generated by thyroidectomy combined with levothyroxine administration. The transcriptomics analysis was performed using aborted placenta. Afterward, the effects of JPT2 on trophoblast cells were explored using gain-and loss-of-function experiments.

RESULTS

Transcriptomics analysis showed 1286 downregulated genes and 2300 upregulated genes in the aborted placenta, and JPT2 was significantly downregulated in the aborted placenta from SCH rats. Afterward, gain-and loss-of-function experiments exhibited that overexpression of JPT2 promoted the proliferation, migration, invasion, spheroid formation of HTR-8/SVneo trophoblast cells and their attachment to endometrial stromal cells, while these biological behaviors were suppressed by JPT2 knockdown. Furthermore, JPT2 accelerated the transcription of leptin receptor (LEPR), and activated signal transducer and activator of transcription 3 (STAT3) signal in a transcription factor AP-2γ-dependent manner. In addition, silencing of LEPR abolished the role of JPT2.

CONCLUSION

Our results revealed that JPT2, which was downregulated in the aborted placenta from SCH rats, promoted proliferation, migration, invasion, spheroid formation, and attachment of trophoblast cells via regulating LEPR/STAT3 axis as a transcription co-factor. It is indicated that low expression of JPT2 may contribute to the abortion in individuals with SCH.

Adipokines in pregnancy

Reproductive success consists of a sequential events chronology, starting with the ovum fertilization, implantation of the embryo, placentation, and cellular processes like proliferation, apoptosis, angiogenesis, endocrinology, or metabolic changes, which taken together finally conduct the birth of healthy offspring. Currently, many factors are known that affect the regulation and proper maintenance of pregnancy in humans, domestic animals, or rodents. Among the determinants of reproductive success should be distinguished: the maternal microenvironment, genes, and proteins as well as numerous pregnancy hormones that regulate the most important processes and ensure organism homeostasis. It is well known that white adipose tissue, as the largest endocrine gland in our body, participates in the synthesis and secretion of numerous hormones belonging to the adipokine family, which also may regulate the course of pregnancy. Unfortunately, overweight and obesity lead to the expansion of adipose tissue in the body, and its excess in both women and animals contributes to changes in the synthesis and release of adipokines, which in turn translates into dramatic changes during pregnancy, including those taking place in the organ that is crucial for the proper progress of pregnancy, i.e. the placenta. In this chapter, we are summarizing the current knowledge about levels of adipokines and their role in the placenta, taking into account the physiological and pathological conditions of pregnancy, e.g. gestational diabetes mellitus, preeclampsia, or intrauterine growth restriction in humans, domestic animals, and rodents.

Leptin receptor Gln223Arg and Lys109Arg polymorphisms may be associated with HBV-related hepatocellular carcinoma risk: A system review and meta-analysis

Increasing evidence has suggested a strong association of hepatocellular carcinoma (HCC) susceptibility and Gln223Arg (rs1137101) and Lys109Arg (rs1137100) polymorphisms in leptin receptor (LEPR) genes. To provide a quantitative assessment for such correlation, we reviewed all related systems and conducted meta-analysis for case and control researches. A literature search of Web of Science, EMBASE, PubMed, Scopus as well as China National Knowledge Infrastructure databases was collected. 95% confidence intervals (95% CIs) together with odds ratios (ORs) were calculated. Five case-control researches consisting of 1323 cases and 1919 control cases were incorporated into meta-analysis. Researches indicated A-allelic and AA genotype of rs1137101 were substantially related to boosted susceptibility of hepatitis B virus (HBV)-related HCC (mutant model, OR = 1.81, 95% CI = 1.36-2.41, p < .001; allelic model, OR = 1.55, 95% CI = 1.32-1.83, p < .001). On the contrary, we observed GG genotype of rs1137101 substantially related to reduced risk of HBV-related HCC (wild model, OR 0.59, 95%CI = 0.46-0.75, p < .001). We observed AA genotype of rs1137100 relevant to boosted HCC risk (mutant model, OR = 1.51, 95%CI = 1.14-2.01, p = .005) as well as in those with HBV-related HCCs (homozygous model, OR = 2.12, 95%CI = 1.49-3.02, p < .001; mutant model, OR = 1.67, 95%CI = 1.23-2.26, p = .001). G-allele and AA genotype of rs1137101 might be in connection with boosted HBV-related HCC susceptibility, and wild-type GG genotype might prevent diseases. AA genotype of rs1137100 might also improve HBV-related HCC susceptibility. Such conclusions ought to be validated by larger and better-designed researches.

Is the leptin/BMI ratio a reliable biomarker for endometriosis?

Background

The aim of this study was to analyze the concentration of leptin in peritoneal fluid and plasma and to assess their role as potential biomarkers in the diagnosis of endometriosis.

Materials & methods

Leptin adjusted for BMI (leptin/BMI ratio) was measured using surface plasmon resonance imaging (SPRI) biosensors. Patients with suspected endometriosis were included in the study. Plasma was collected from 70 cases, and peritoneal fluid from 67 cases. Based on the presence of endometriosis lesions detected during laparoscopy, patients were divided into a study group and a control group (patients without endometriosis).

Results

Leptin/BMI ratio in plasma did not differ between women with endometriosis and the control group (0.7159 ± 0.259 vs 0.6992 ± 0.273, p= 0,7988). No significant differences were observed in peritoneal leptin/BMI ratio levels in patients with and without endometriosis (0.6206 ± 0.258 vs 0.6215 ± 0.264, p= 0,9896). Plasma and peritoneal leptin/BMI ratios were significantly lower in women with endometriosis - related primary infertility compared to women with endometriosis without primary infertility (0.640 ± 0.502 vs 0.878 ± 0.623, p < 0.05). The difference was observed in case of primary infertility, but not in terms of the secondary one. No significant differences were noted between leptin/BMI ratio in the proliferative phase and the secretory phase (0.716 ± 0.252 vs 0.697 ± 0.288, p= 0,7785).

Conclusion

The results of present study do not support the relevance of leptin concentration determination as a biomarker of the endometriosis. Due to the limited number of samples in the tested group, further studies are needed to confirm its role.

Leptin effects: focusing on the relationship between obesity and male infertility

The human male infertility has several causes interconnected to improper lifestyles such as smoking, sedentarism, environmental factors, toxins accumulation and energy imbalances. All these factors contribute to the obesity accompanied metabolic syndrome and hormonal alterations in the leptin-ghrelin axis. The leptin (Lep) has many pleiotropic effects in several biological systems, directly on the peripheral tissues or through the central nervous system. Many studies suggest that Lep is a key player in gonadal functions beside its documented role in reproductive regulation; however, further investigations are still necessary to elucidate all the molecular pathways involved in these mechanisms. Keeping into account that increased Lep levels in obese men are positively correlated with altered sperm parameters and testicular oxidative stress, evidence refers to Lep as a potential link between obesity and male infertility. This review represents an updated version on the concept of the Lep roles in mediating the male reproductive functions in obese patients.

Physiological Appetite Regulation and Bariatric Surgery

Obesity remains a common metabolic disorder and a threat to health as it is associated with numerous complications. Lifestyle modifications and caloric restriction can achieve limited weight loss. Bariatric surgery is an effective way of achieving substantial weight loss as well as glycemic control secondary to weight-related type 2 diabetes mellitus. It has been suggested that an anorexigenic gut hormone response following bariatric surgery contributes to weight loss. Understanding the changes in gut hormones and their contribution to weight loss physiology can lead to new therapeutic treatments for weight loss. Two distinct types of neurons in the arcuate hypothalamic nuclei control food intake: proopiomelanocortin neurons activated by the anorexigenic (satiety) hormones and neurons activated by the orexigenic peptides that release neuropeptide Y and agouti-related peptide (hunger centre). The arcuate nucleus of the hypothalamus integrates hormonal inputs from the gut and adipose tissue (the anorexigenic hormones cholecystokinin, polypeptide YY, glucagon-like peptide-1, oxyntomodulin, leptin, and others) and orexigeneic peptides (ghrelin). Replicating the endocrine response to bariatric surgery through pharmacological mimicry holds promise for medical treatment. Obesity has genetic and environmental factors. New advances in genetic testing have identified both monogenic and polygenic obesity-related genes. Understanding the function of genes contributing to obesity will increase insights into the biology of obesity. This review includes the physiology of appetite control, the influence of genetics on obesity, and the changes that occur following bariatric surgery. This has the potential to lead to the development of more subtle, individualised, treatments for obesity.

Role of Leptin in Obesity, Cardiovascular Disease, and Type 2 Diabetes

Diabetes mellitus (DM) is a highly prevalent disease worldwide, estimated to affect 1 in every 11 adults; among them, 90-95% of cases are type 2 diabetes mellitus. This is partly attributed to the surge in the prevalence of obesity, which has reached epidemic proportions since 2008. In these patients, cardiovascular (CV) risk stands as the primary cause of morbidity and mortality, placing a substantial burden on healthcare systems due to the potential for macrovascular and microvascular complications. In this context, leptin, an adipocyte-derived hormone, plays a fundamental role. This hormone is essential for regulating the cellular metabolism and energy balance, controlling inflammatory responses, and maintaining CV system homeostasis. Thus, leptin resistance not only contributes to weight gain but may also lead to increased cardiac inflammation, greater fibrosis, hypertension, and impairment of the cardiac metabolism. Understanding the relationship between leptin resistance and CV risk in obese individuals with type 2 DM (T2DM) could improve the management and prevention of this complication. Therefore, in this narrative review, we will discuss the evidence linking leptin with the presence, severity, and/or prognosis of obesity and T2DM regarding CV disease, aiming to shed light on the potential implications for better management and preventive strategies.

Metabolic Water As a Route for Water Acquisition in Vertebrates Inhabiting Dehydrating Environments

Vertebrates have expanded their habitats during evolution, which accompanies diversified routes for water acquisition. Water is acquired by oral intake and subsequent absorption by the intestine in terrestrial and marine animals which are subjected to constant dehydration, whereas most water is gained osmotically across body surfaces in freshwater animals. In addition, a significant amount of water, called metabolic water, is produced within the body by the oxidation of hydrogen in organic substrates. The importance of metabolic water production as a strategy for water acquisition has been well documented in desert animals, but its role has attracted little attention in marine animals which also live in a dehydrating environment. In this article, the author has attempted to reevaluate the role of metabolic water production in body fluid regulation in animals inhabiting desiccating environments. Because of the exceptional ability of their kidney, marine mammals are thought to typically gain water by drinking environmental seawater and excreting excess NaCl in the urine. On the other hand, it is established that marine teleosts drink seawater to enable intestinal water and ion absorption, and the excess NaCl is excreted by branchial ionocytes. In addition to the oral route, we suggest through experiments using eels that water production by lipid metabolism is an additional route for water acquisition when they encounter seawater. It seems that metabolic water production contributes to counteract dehydration before mechanisms for water regulation are reversed from excretion in freshwater to acquisition in seawater.

Leptin and male fertility: unraveling the molecular pathways, receptor functions, and therapeutic potential

Leptin, an adipokine hormone, is a critical regulator of energy homeostasis, appetite, and metabolism. Recent advances have elucidated its role in male fertility. This forum provides an overview of the interplay between leptin, its receptors, and signaling pathways in the context of male fertility, revealing its multifaceted impact on reproductive health.

NK cells vs. obesity: A tale of dysfunction & redemption

Natural killer (NK) cells are critical in protecting the body against infection and cancer. NK cells can rapidly respond to these threats by directly targeting the infected or transformed cell using their cytotoxic machinery or by initiating and amplifying the immune response via their production of cytokines. Additionally, NK cells are resident across many tissues including adipose, were their role extends from host protection to tissue homeostasis. Adipose resident NK cells can control macrophage polarization via cytokine production, whilst also regulating stressed adipocyte fate using their cytotoxic machinery. Obesity is strongly associated with increased rates of cancer and a heightened susceptibility to severe infections. This is in part due to significant obesity-related immune dysregulation, including defects in both peripheral and adipose tissue NK cells. In this review, we detail the literature to date on NK cells in the setting of obesity - outlining the consequences, mechanisms and therapeutic interventions.

Dysregulation of adipokines levels among healthy first-degree relatives of type 2 diabetes patients

Background

Leptin, adiponectin and its ratio (L/A), as well as adipocyte fatty acid binding protein (A-FABP) have shown association to type 2 diabetes and atherosclerosis. Since first degree relatives (FDR) of type 2 diabetes are known to have higher risks of developing aforementioned diseases, this study aimed to see differences in adipokines profiles between FDR of type 2 diabetes and non-FDR counterpart.

Methods

Age, sex and body mass index (BMI)-matched normotensive-normoglycemic subjects, aged 19-39 years with BMI<30 kg/m2, were included in this cross-sectional study. Serum adiponectin, leptin, and A-FABP levels were measured by sandwich ELISA while HOMA-IR was calculated from fasting blood glucose and insulin levels.

Results

Of 116 subjects recruited, there were significant difference of insulin level (6.00 vs 5.00 μIU/mL, P = 0.029) and HOMA-IR (1.27 vs 1.10, P = 0.028). Adiponectin, leptin, L/A ratio, and A-FABP levels were not statistically different between FDR and non-FDR groups. Stratified by BMI, non-obese FDR had higher L/A ratio (0.83 vs 0.49, P = 0.020) compared to those of corresponding non-FDR. In multivariate analysis, after adjusting for age, sex, waist circumference, BMI, and metabolic profiles (HbA1C, HOMA-IR, LDL-C, HDL-C, and triglyceride levels), FDR status became significantly associated with adiponectin level, and in non-obese subgroup, remained its significance with L/A ratio.

Conclusion

The FDR status was independently associated with adiponectin level. Furthermore, higher L/A ratio was more pronounced in non-obese FDR than those of non-FDR subjects, suggesting that FDR status may already contribute to the development of adipokines dysregulation before obesity occurs.

Association between serum interleukin-6, leptin and insulin in gestational diabetes mellitus - a cross- sectional study

Purpose

Gestational diabetes mellitus (GDM) is a state of leptin resistance which develops a vicious cycle of hyperinsulinemia and hyperleptinemia leading to aggravation of an inflammatory situation. This study was done to find out the association between IL-6, leptin and insulin in gestational diabetes among North Indian women.

Method

This cross-sectional study included 100 GDM, 100 non-GDM and 50 non-pregnant women. DIPSI (Diabetes in Pregnancy Study Group India) criteria was used for screening GDM among pregnant women. GDM and non-GDM pregnant women were further categorized into three groups according to the trimester of pregnancy. Serum IL-6, leptin and insulin were measured in all the enrolled women.

Results

Serum IL-6 levels were significantly higher among GDM women as compared to non-GDM and non-pregnant women. Although the mean serum leptin and insulin levels were higher in GDM, but the difference was not statistically significant. When GDM and non-GDM women were categorized into three trimester, serum leptin levels were found to be significantly higher in 3rd trimester (p < 0.002) and IL-6 in 1st trimester (p < 0.017) among GDM women. No correlation was found between serum IL-6, leptin and insulin in GDM.

Conclusion

Absence of any significant association between leptin and IL-6 signifies that leptin may not be associated with inflammation in gestational diabetes. However, IL-6 may serve as an early marker for screening glucose intolerance during pregnancy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01188-3.

Regulation of cardiovascular health and disease by visceral adipose tissue-derived metabolic hormones

Visceral adipose tissue (VAT) is a metabolic organ known to regulate fat mass, and glucose and nutrient homeostasis. VAT is an active endocrine gland that synthesizes and secretes numerous bioactive mediators called 'adipocytokines/adipokines' into systemic circulation. These adipocytokines act on organs of metabolic importance like the liver and skeletal muscle. Multiple preclinical and in vitro studies showed strong evidence of the roles of adipocytokines in the regulation of metabolic disorders like diabetes, obesity and insulin resistance. Adipocytokines, such as adiponectin and omentin, are anti-inflammatory and have been shown to prevent atherogenesis by increasing nitric oxide (NO) production by the endothelium, suppressing endothelium-derived inflammation and decreasing foam cell formation. By inhibiting differentiation of vascular smooth muscle cells (VSMC) into osteoblasts, adiponectin and omentin prevent vascular calcification. On the other hand, adipocytokines like leptin and resistin induce inflammation and endothelial dysfunction that leads to vasoconstriction. By promoting VSMC migration and proliferation, extracellular matrix degradation and inflammatory polarization of macrophages, leptin and resistin increase the risk of atherosclerotic plaque vulnerability and rupture. Additionally, the plasma concentrations of these adipocytokines alter in ageing, rendering older humans vulnerable to cardiovascular disease. The disturbances in the normal physiological concentrations of these adipocytokines secreted by VAT under pathological conditions impede the normal functions of various organs and affect cardiovascular health. These adipokines could be used for both diagnostic and therapeutic purposes in cardiovascular disease.

SERPINE1 mRNA Binding Protein 1 Is Associated with Ischemic Stroke Risk: A Comprehensive Molecular-Genetic and Bioinformatics Analysis of SERBP1 SNPs

The SERBP1 gene is a well-known regulator of SERPINE1 mRNA stability and progesterone signaling. However, the chaperone-like properties of SERBP1 have recently been discovered. The present pilot study investigated whether SERBP1 SNPs are associated with the risk and clinical manifestations of ischemic stroke (IS). DNA samples from 2060 unrelated Russian subjects (869 IS patients and 1191 healthy controls) were genotyped for 5 common SNPs-rs4655707, rs1058074, rs12561767, rs12566098, and rs6702742 SERBP1-using probe-based PCR. The association of SNP rs12566098 with an increased risk of IS (risk allele C; p = 0.001) was observed regardless of gender or physical activity level and was modified by smoking, fruit and vegetable intake, and body mass index. SNP rs1058074 (risk allele C) was associated with an increased risk of IS exclusively in women (p = 0.02), non-smokers (p = 0.003), patients with low physical activity (p = 0.04), patients with low fruit and vegetable consumption (p = 0.04), and BMI ≥25 (p = 0.007). SNPs rs1058074 (p = 0.04), rs12561767 (p = 0.01), rs12566098 (p = 0.02), rs6702742 (p = 0.036), and rs4655707 (p = 0.04) were associated with shortening of activated partial thromboplastin time. Thus, SERBP1 SNPs represent novel genetic markers of IS. Further studies are required to confirm the relationship between SERBP1 polymorphism and IS risk.

Chinese chestnut shell polyphenol extract regulates the JAK2/STAT3 pathway to alleviate high-fat diet-induced, leptin-resistant obesity in mice

Chinese chestnut shell is a by-product of chestnut food processing and is rich in polyphenols. This study sought to investigate the effect of chestnut shell polyphenol extract (CSP) on weight loss and lipid reduction in a 12-week high-fat diet (HFD)-induced murine obesity model. CSP (300 mg per kg body weight) was administered intragastrically daily. AG490, a JAK2 protein tyrosine kinase inhibitor, was also intraperitoneally injected. The results showed that an HFD induced leptin resistance (LR). Compared to corresponding values in the HFD group, CSP treatment improved blood lipid levels, weight, and leptin levels in obese mice (p < 0.01). Additionally, CSP treatment enhanced enzyme activity by improving total antioxidant capacity, attenuating oxidative stress, and reducing fat droplet accumulation and inflammation in the liver, epididymal, and retroperitoneal adipose tissue. CSP also activated the LEPR-JAK2/STAT3-PTP1B-SOCS-3 signal transduction pathway in hypothalamus tissue and improved LR while regulating the expression of proteins related to lipid metabolism (PPARγ, FAS, and LPL) in white adipose tissue in the retroperitoneal cavity. However, the amelioration of lipid metabolism by CSP was dependent on JAK2. Molecular docking simulation further demonstrated the strong binding affinity of procyanidin C1 (-10.3983297 kcal mol^-1) and procyanidin B1 (-9.12686729 kcal mol^-1) to the crystal structure of JAK2. These results suggest that CSP may be used to reduce HFD-induced obesity with potential application as a functional food additive.

Adipocytokine correlates of childhood and adolescent mental health: A systematic review

The objective of this systematic review was to determine the current state of the literature regarding how adipocytokines associate with mental health symptoms/disorders in youth. Findings summarized in this review suggested that in neurodevelopmental disorders, higher levels of leptin, ghrelin, resistin, and visfatin as well as lower levels of adiponectin, retinol-binding protein 4, and progranulin predicted increased risk for or were conflated with autism spectrum disorder. Adipocytokine correlates of attention-deficit hyperactivity disorder and related symptoms included higher apelin, higher leptin-to-adiponectin ratio, and lower adiponectin. Evidence from studies examining anxiety symptoms evinced mixed results regarding leptin, and one study suggested higher levels of ghrelin. Depressive symptoms correlated with higher leptin and ghrelin. Research examining posttraumatic stress symptoms found higher levels of ghrelin. In research examining broadband symptoms, conflicting results emerged for associations between internalizing symptoms (i.e., symptoms of emotional stress) and leptin in youth. Low levels of adiponectin and high levels of leptin predicted externalizing symptoms. Total symptom difficulties were associated with a higher leptin-to-adiponectin ratio. Our findings suggest that adipocytokines may be an important set of biomarkers to consider as underlying mechanisms contributing to developmental psychopathology.

Maca modulates fat and liver energy metabolism markers insulin, IRS1, leptin, and SIRT1 in rats fed normal and high-fat diets

Maca root extract on insulin, insulin receptor substrate-1 (IRS1), leptin, and NAD-dependent deacetylase sirtuin-1 (SIRT1), as well as body weight changes evaluated in this study for a 60 days model of normal and high-fat diet (HFD) fed rats. 28 male rats allocated to four groups: (i) Control, (ii) Maca (40 mg/kg/day), (iii) HFD, and (iv) HFD + Maca. After the 60 days of study, fat tissue and liver insulin levels decreased in the HFD and HFD + Maca groups in comparison to Control and Maca groups (p < .001). Maca group showed a significant IRS1 increase in the fat tissue (p < .0001). Leptin levels were the highest in the Maca group and the lowest in the HFD group in the fat tissue (p < .01). SIRT1 levels were found the highest in the Maca groups (p < .01). These results show the protective and regulatory effectiveness of Maca when fed with a normal or HFD diet.

Leptin and leptin receptor expression as biomarkers for breast cancer: a retrospective study

BACKGROUND

Effective screening and treatment have reduced the number of women dying from breast cancer (BC). However, the long-term sequelae of BC treatment and psychosocial factors seriously affect the life quality of BC patients and survivors. Therefore, the discovery and application of targeted biomarkers to improve the functional outcome and life quality of BC patients is necessary.

AIMS

To explore the impact of leptin (LEP)/ leptin receptor (LEPR) expression on occurrence and survival of BC.

METHODS

Totally 132 primary BC and 66 non-BC patients who underwent surgery in department of breast surgery in Shanxi Cancer Hospital from January to October in 2009 were enrolled in this retrospective study. LEP and LEPR were examined in BC tissues, benign breast tissues, para-carcinoma tissues using immunohistochemical staining. Kaplan-Meier curve was generated to test survival time.

RESULTS

The high level expression of LEP and LEPR in BC tissues were significantly higher than that in benign breast tissues and in para-carcinoma tissues (all P < 0.05). The LEP expression in patients with lymph node metastases was significantly higher than that in patients without lymph nodes metastases (P = 0.002). LEPR expression was correlated with higher Ki-67 rate (P = 0.002). LEP and LEPR both had no impact on survival (all P > 0.05).

CONCLUSIONS

High LEP/LEPR expression were risk factors for occurrence of BC, but without impact on survival.

Overview and New Insights into the Metabolic Syndrome: Risk Factors and Emerging Variables in the Development of Type 2 Diabetes and Cerebrocardiovascular Disease

Metabolic syndrome (MetS) is considered a metabolic disorder that has been steadily increasing globally and seems to parallel the increasing prevalence of obesity. It consists of a cluster of risk factors which traditionally includes obesity and hyperlipidemia, hyperinsulinemia, hypertension, and hyperglycemia. These four core risk factors are associated with insulin resistance (IR) and, importantly, the MetS is known to increase the risk for developing cerebrocardiovascular disease and type 2 diabetes mellitus. The MetS had its early origins in IR and syndrome X. It has undergone numerous name changes, with additional risk factors and variables being added over the years; however, it has remained as the MetS worldwide for the past three decades. This overview continues to add novel insights to the MetS and suggests that leptin resistance with hyperleptinemia, aberrant mitochondrial stress and reactive oxygen species (ROS), impaired folate-mediated one-carbon metabolism with hyperhomocysteinemia, vascular stiffening, microalbuminuria, and visceral adipose tissues extracellular vesicle exosomes be added to the list of associated variables. Notably, the role of a dysfunctional and activated endothelium and deficient nitric oxide bioavailability along with a dysfunctional and attenuated endothelial glycocalyx, vascular inflammation, systemic metainflammation, and the important role of ROS and reactive species interactome are discussed. With new insights and knowledge regarding the MetS comes the possibility of new findings through further research.

Association of Leptin and Retinol Binding Protein 4 with the Risk of Gestational Diabetes: A Systematic Review and Meta-Analysis of Observational Studies

The positive correlation between serum levels of retinol binding protein 4 (RBP4) and gestational diabetes (GDM) has been proven in the previous meta-analysis on case-control studies. However, its association with serum levels of leptin is not studied in any meta-analysis. Therefore, we performed an updated systematic review of observational studies evaluating the association between serum RBP4 and leptin with the risk of GDM. A systematic search was performed on four databases, including PubMed, Scopus, Web of Science, and Google Scholar, up to March 2021. After screening and deleting duplicates, nine articles met our inclusion criteria. Studies had case-control and cohort design, and included 5074 participants with a mean age range between 18 and 32.65 years (2359 participants for RBP4 and 2715 participants for leptin). Interestingly, this meta-analysis revealed higher levels of RBP4 (OR=2.04; 95% CI: 1.37, 3.04) and leptin (OR=2.32; 95% CI: 1.39, 3.87) are significantly associated with the increased risk of overall GDM. The subgroup analysis approved the results based on the study design, trimester of pregnancy and serum/plasms to investigate the source of heterogeneity. The present meta-analysis determines serum leptin and RBP4 levels as predictors of GDM occurrence. However, studies included in this meta-analysis showed significant heterogeneity.

Global analysis of the association between pig muscle fatty acid composition and gene expression using RNA-Seq

Fatty acids (FAs) play an essential role as mediators of cell signaling and signal transduction, affecting metabolic homeostasis and determining meat quality in pigs. However, FAs are transformed by the action of several genes, such as those encoding desaturases and elongases of FAs in lipogenic tissues. The aim of the current work was to identify candidate genes, biological processes, and pathways involved in the modulation of intramuscular FA profile from longissimus dorsi muscle. FA profile by gas chromatography of methyl esters and gene expression by RNA-Seq were determined in 129 Iberian × Duroc backcrossed pigs. An association analysis between the muscle transcriptome and its FA profile was performed, followed by a concordance and functional analysis. Overall, a list of well-known (e.g., PLIN1, LEP, ELOVL6, SC5D, NCOA2, ACSL1, MDH1, LPL, LGALS12, TFRC, GOT1, and FBP1) and novel (e.g., TRARG1, TANK, ENSSSCG00000011196, and ENSSSCG00000038429) candidate genes was identified, either in association with specific or several FA traits. Likewise, several of these genes belong to biological processes and pathways linked to energy, lipid, and carbohydrate metabolism, which seem determinants in the modulation of FA compositions. This study can contribute to elucidate the complex relationship between gene expression and FA profile in pig muscle.

Effects of leptin on the viability of human ovarian cancer cells and changes in cytokine expression levels

Background

Obesity is associated with increased mortality among ovarian cancer and is a poor prognostic factor. There are significant links between the leptin hormone, a product of the obesity gene, and the development of ovarian cancer. Leptin is a vital hormone-like cytokine secreted from adipose tissue and is mainly involved in the maintenance of energy homeostasis. It regulates several intracellular signaling pathways and also interacts with various hormones and energy regulators. It acts as a growth factor by stimulating cell proliferation and differentiation and in this way contributes to cancer cell development. The aim of the study was to investigate the effects of leptin on human ovarian cancer cells.

Methods

In this study, the effects of increasing the concentration of leptin were investigated on the cell viability of OVCAR-3 and MDAH-2774 ovarian cancer lines by MTT assay. Moreover, to elucidate the molecular mechanisms of leptin in ovarian cancer cells, changes in the expression levels of 80 cytokines were evaluated after leptin treatment via a human cytokine antibody array.

Results

Leptin increases the proliferation of both ovarian cancer cell lines. IL-1 level was increased in OVCAR-3 cells and TGF-β level was increased in MDAH-2774 cells after leptin treatment. A decrease in IL-2, MCP-2/CCL8 and MCP-3/CCL7 levels was detected in both ovarian cancer cell lines with leptin administration. An increase in IL-3 and IL-10 expressions, insulin-like growth factor binding proteins (IGFBP) IGFBP-1, IGFBP-2 and IGFBP-3 levels were detected in both ovarian cancer cell lines with leptin administration. In conclusion; leptin has a proliferative effect on human ovarian cancer cell lines and affects different cytokines in different types of ovarian cancer cells.

Influence of Training and Single Exercise on Leptin Level and Metabolism in Obese Overweight and Normal-Weight Women of Different Age

Leptin is one of the important hormones secreted by adipose tissue. It participates in the regulation of energy processes in the body through central and peripheral mechanisms. The aim of this study was to analyse the anthropological and physical performance changes during 9 month training in women of different age and body mass. The additional aim was the analysis of leptin levels in the fasting stage and after a control exercise. Obese (O), overweight (OW), and normal-weight (N) women participated in the study. Additional subgroups of premenopausal (PRE) (<50 years) and postmenopausal (POST) (50+) women were created for leptin level analysis. The main criterion of the division into subgroups was the age of menopause in the population. The control submaximal test and maximal oxygen uptake (VO_2max) according to Astrand-Rhyming procedures was performed at baseline and after 3, 6, and 9 months. Before each control test, body weight (BM), body mass index (BMI), percentage of adipose tissue (% FAT), and mass (FAT (kg)) were measured. Moreover, before and after each test, leptin level was measured. After 9 months, there was a significant decrease in BM in the O (p < 0.05) and OW (p < 0.05) groups with no significant changes in the N group. There was a decrease in BMI in both the O (p < 0.05) and the OW (p < 0.05) groups, with no changes in the N group. The % FAT reduction was noted only in the O group (p < 0.05). VO_2max increased in each of the measured groups (p < 0.05). The fasting leptin level at 0, 3, 6, and 9 months were the highest in the O group. The fasting leptin level before training was highest in the O group compared to the OW group (p < 0.01) and the N group (p < 0.01). It was also higher in the OW group compared to the N group at baseline (0) (p < 0.01) and after 3 and 6 months (p < 0.01). After 9 months, the leptin concentration decreased by 20.2% in the O group, 40.7% in the OW group, and 33% in the N group. Moreover, the fasting leptin level was higher in the POST subgroup compared to the PRE group in the whole group of women (p < 0.05). After a single exercise, the level of leptin in the whole study group decreased (p < 0.05). This was clearly seen, especially in the POST group. The 9 month training had a reducing effect on the blood leptin concentration in groups O, OW, and N. This may have been a result of weight loss and the percentage of fat in the body, as well as systematically disturbed energy homeostasis.

Presence of leptin and its receptor in the ram reproductive system and in vitro effect of leptin on sperm quality

Leptin is a 16 kDa hormone encoded by obese (OB) gene in adipocytes. This molecule not only regulates energy metabolism but also plays a role in the reproduction of mammals. Leptin and its receptor (OBR) have been found in male reproductive systems of human, bovine, equine and pig. The effects of leptin on sperm quality vary widely from different research findings. However, the presence of leptin and its receptor in the ram reproductive system and the in vitro effect of leptin on sperm quality have not reported yet. In the present study, we found that the OB was highly expressed in primary and secondary spermatocytes of the testes, OBR was highly expressed in secondary spermatocytes of the testes. The expressions of OB were in stereocilia of epididymis and in columnar cells of epididymal caput and cauda, the expressions of OBR were in columnar cells of epididymis and in stereocilia of epididymal corpus and cauda. The presence of both OB and OBR in testes, epididymis and sperm were confirmed through RT-PCR, immunolocalization and Western blot analyses. The RT-qPCR results indicated OB and OBR had higher expression levels in epididymal sperm than that of the ejaculated sperm in rams. When sperm were treated with 5 ng/mL leptin, the progressive motility (P < 0.01), straight-line velocity (VSL) (P < 0.05), average path velocity (VAP) (P < 0.05), membrane mitochondrial potential (MMP) (P < 0.01) and viability (P < 0.05) significantly increased, while DNA fragmentation index (DFI) and reactive oxygen species (ROS) significantly decreased compared to the control (P < 0.01), and the other semen parameters such as acrosome integrity and acrosome reaction rate had no significant changes between groups (P > 0.05). In conclusion, this is probably the first report describing localization of leptin and its receptors in the reproductive system of rams and their effects on sperm quality parameters. Our findings suggest that 5 ng/mL leptin treatment enhanced sperm motility, viability and MMP, and decrease DFI and ROS without obvious influence on the acrosome reaction in ram sperm. The potential mechanisms may be related to leptin's ability to reduce the oxidative stress and apoptosis of sperms and improve their mitochondrial function and energy supply, therefore, to maintain the physiological homeostasis of the sperm.

Age-Related NAFLD: The Use of Probiotics as a Supportive Therapeutic Intervention

Human aging, a natural process characterized by structural and physiological changes, leads to alterations of homeostatic mechanisms, decline of biological functions, and subsequently, the organism becomes vulnerable to external stress or damage. In fact, the elderly population is prone to develop diseases due to deterioration of physiological and biological systems. With aging, the production of reactive oxygen species (ROS) increases, and this causes lipid, protein, and DNA damage, leading to cellular dysfunction and altered cellular processes. Indeed, oxidative stress plays a key role in the pathogenesis of several chronic disorders, including hepatic diseases, such as non-alcoholic fatty liver disease (NAFLD). NAFLD, the most common liver disorder in the Western world, is characterized by intrahepatic lipid accumulation; is highly prevalent in the aging population; and is closely associated with obesity, insulin resistance, hypertension, and dyslipidemia. Among the risk factors involved in the pathogenesis of NAFLD, the dysbiotic gut microbiota plays an essential role, leading to low-grade chronic inflammation, oxidative stress, and production of various toxic metabolites. The intestinal microbiota is a dynamic ecosystem of microbes involved in the maintenance of physiological homeostasis; the alteration of its composition and function, during aging, is implicated in different liver diseases. Therefore, gut microbiota restoration might be a complementary approach for treating NAFLD. The administration of probiotics, which can relieve oxidative stress and elicit several anti-aging properties, could be a strategy to modify the composition and restore a healthy gut microbiota. Indeed, probiotics could represent a valid supplement to prevent and/or help treating some diseases, such as NAFLD, thus improving the already available pharmacological intervention. Moreover, in aging, intervention of prebiotics and fecal microbiota transplantation, as well as probiotics, will provide novel therapeutic approaches. However, the relevant research is limited, and several scientific research works need to be done in the near future to confirm their efficacy.

Sex Differences in Adiposity and Cardiovascular Diseases

Body fat distribution is a well-established predictor of adverse medical outcomes, independent of overall adiposity. Studying body fat distribution sheds insights into the causes of obesity and provides valuable information about the development of various comorbidities. Compared to total adiposity, body fat distribution is more closely associated with risks of cardiovascular diseases. The present review specifically focuses on the sexual dimorphism in body fat distribution, the biological clues, as well as the genetic traits that are distinct from overall obesity. Understanding the sex determinations on body fat distribution and adiposity will aid in the improvement of the prevention and treatment of cardiovascular diseases (CVD).

The role of hypoleptinemia in the psychological and behavioral adaptation to starvation: implications for anorexia nervosa

This narrative review aims to pinpoint mental and behavioral effects of starvation, which may be triggered by hypoleptinemia and as such may be amenable to treatment with leptin receptor agonists. The reduced leptin secretion results from the continuous loss of fat mass, thus initiating a graded triggering of diverse starvation related adaptive functions. In light of leptin receptors located in several peripheral tissues and many brain regions adaptations may extend beyond those of the hypothalamus-pituitary-end organ-axes. We focus on gastrointestinal tract and reward system as relevant examples of peripheral and central effects of leptin. Despite its association with extreme obesity, congenital leptin deficiency with its many parallels to a state of starvation allows the elucidation of mental symptoms amenable to treatment with exogenous leptin in both ob/ob mice and humans with this autosomal recessive disorder. For starvation induced behavioral changes with an intact leptin signaling we particularly focus on rodent models for which proof of concept has been provided for the causative role of hypoleptinemia. For humans, we highlight the major cognitive, emotional and behavioral findings of the Minnesota Starvation Experiment to contrast them with results obtained upon a lesser degree of caloric restriction. Evidence for hypoleptinemia induced mental changes also stems from findings obtained in lipodystrophies. In light of the recently reported beneficial cognitive, emotional and behavioral effects of metreleptin-administration in anorexia nervosa we discuss potential implications for the treatment of this eating disorder. We postulate that leptin has profound psychopharmacological effects in the state of starvation.

Inflammation as a link between periodontal disease and obesity

Nutrition plays a critical role in the homeostatic balance, maintenance of health, and longevity. There is a close link between inflammatory diseases and nutritional health. Obesity is a severe pathological process with grave implications on several organ systems and disease processes, including type 2 diabetes, cardiovascular disease, osteoarthritis, and rheumatoid arthritis. The impact of obesity on periodontal inflammation has not been fully understood; the association between nutritional balance and periodontal inflammation is much less explored. This review is focused on the potential mechanistic links between periodontal diseases and obesity and common inflammatory activity pathways that can be pharmacologically targeted.

Restlessness and an Increased Urge to Move (Drive for Activity) in Anorexia Nervosa May Strengthen Personal Motivation to Maintain Caloric Restriction and May Augment Body Awareness and Proprioception: A Lesson From Leptin Administration in Anorexia Nervosa

Anorexia nervosa (AN), a disorder of voluntary food restriction leading to severe weight loss in female adolescents, remains an enigma. In particular, the appropriation of the starved thin body into the self-concept in AN is a process insufficiently researched and still poorly understood. Healthy humans undergoing starvation experience a slowing of movements and avoid voluntary exercise. By contrast, AN tends to be not infrequently associated with voluntary, sometimes excessive and/or compulsive exercise. Such deliberate exercise, not reported in starvation, seems to be facilitated by an increased urge for movement and physical restlessness, particular to AN. The increased urge to move would reflect spontaneous daily activity, the energy expended for everything that is not sleeping, eating, or voluntary exercise. Our hypothesis is that the starvation-induced increased urge to move and restlessness may promote the development of AN. Reversal of the fasting state, by either high caloric food or by leptin administration, would be expected to reduce restlessness and the increased urge to move along with improvement in other symptoms in AN. This review explores the idea that such restless activation in AN, in itself and through accelerating body weight loss, might foster the integration of the starving body into the self-concept by (1) enhancing the person’s sense of self-control and sense of achievement and (2) through invigorating proprioception and through intensifying the perception of the changing body shape. (3) Tentative evidence from studies piloting leptin administration in chronic AN patients which support this hypothesis is reviewed. The findings show that short term administration of high doses of leptin indeed mitigated depressive feelings, inner tension, intrusive thoughts of food, and the increased urge to be physically active, easing the way to recovery, yet had little influence on the patients’ personal commitment to remain at a low weight. Full recovery then requires resolution of the individuals’ personal unresolved psychological conflicts through psychotherapy and frequently needs specialized treatment approaches to address psychiatric co-morbidities. AN might be conceptualized as a hereditary form of starvation resistance, facilitated by the effects of starvation on fitness allowing for an exceptionally intense personal commitment to perpetuate food restriction.

Sexual Dimorphism in Adipose-Hypothalamic Crosstalk and the Contribution of Aryl Hydrocarbon Receptor to Regulate Energy Homeostasis

There are fundamental sex differences in the regulation of energy homeostasis. Better understanding of the underlying mechanisms of energy balance that account for this asymmetry will assist in developing sex-specific therapies for sexually dimorphic diseases such as obesity. Multiple organs, including the hypothalamus and adipose tissue, play vital roles in the regulation of energy homeostasis, which are regulated differently in males and females. Various neuronal populations, particularly within the hypothalamus, such as arcuate nucleus (ARC), can sense nutrient content of the body by the help of peripheral hormones such leptin, derived from adipocytes, to regulate energy homeostasis. This review summarizes how adipose tissue crosstalk with homeostatic network control systems in the brain, which includes energy regulatory regions and the hypothalamic–pituitary axis, contribute to energy regulation in a sex-specific manner. Moreover, development of obesity is contingent upon diet and environmental factors. Substances from diet and environmental contaminants can exert insidious effects on energy metabolism, acting peripherally through the aryl hydrocarbon receptor (AhR). Developmental AhR activation can impart permanent alterations of neuronal development that can manifest a number of sex-specific physiological changes, which sometimes become evident only in adulthood. AhR is currently being investigated as a potential target for treating obesity. The consensus is that impaired function of the receptor protects from obesity in mice. AhR also modulates sex steroid receptors, and hence, one of the objectives of this review is to explain why investigating sex differences while examining this receptor is crucial. Overall, this review summarizes sex differences in the regulation of energy homeostasis imparted by the adipose–hypothalamic axis and examines how this axis can be affected by xenobiotics that signal through AhR.

Soy isoflavones plus soy protein effects on serum concentration of leptin in adults: A systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Some studies conducted on soy isoflavones and soy protein reflected that leptin can be reduced by soy isoflavones or soy protein. The aim of present study is to assess the effect of soy isoflavones plus soy protein on serum concentration of leptin among adults.

METHODS

To find randomized clinical trails (RCTs) assessing the effect of soy isoflavones containing soy protein on serum concentration of leptin in participants with age ≥18 years old, databases including PubMed, Scopus, ISI Web of Science, Cochrane and ClinicalTrials.gov were searched up to March 2021. We calculated the effect size by the mean change from baseline of leptin concentrations and its standard deviation for intervention and comparison groups. DerSimonian and Laird random effects model was used to estimate the overall summary effect and the heterogeneity. Risk of bias was conducted by Cochrane Collaboration's tool. Study protocol was registered in PROSPERO (No. CRD42021228366).

RESULTS

Eight articles with 421 participants and six articles with 336 participants were known to be eligible for systematic review and meta-analysis, respectively. A pooled analysis revealed that the combination of soy isoflavones and soy protein had a borderline non-significant on serum concentration of leptin (weighted mean difference (WMD): -1.03 ng/ml, 95% confidence interval (CI): -2.11, 0.05 ng/ml). This combination reduced serum leptin levels in studies with baseline levels of leptin ≤22 ng/ml, in short-term trials (≤56 days), studies that used soy isoflavones with dose ≤96 mg/day and among subjects with health risk factors or diseases.

CONCLUSION

Soy isoflavones plus soy protein had a non-significant decreasing effect on the serum concentration of leptin. However, making firm conclusion needs more studies on participants with different health condition, and different soy isoflavones doses and intervention duration.

Plasma VEGF and Leptin Values in Patients With Gastric Intestinal Metaplasia and Metabolic Syndrome

Intestinal metaplasia of the stomach (IM) is considered a pre-cancerous lesion and is a potential precursor to adenocarcinoma. Metabolic syndrome (MetS) has been associated with lesions to the gastrointestinal tract such as the risk of developing Barett esophagus. Vascular endothelial growth factor and leptin have been associated with either gastrointestinal tract carcinogenesis or MetS. In this context, this study was designed to analyze plasma levels of VEGF and leptin in patients with IM and MetS. Four groups of 137 participants (a control group and three patient groups, IM, MetS and IM- MetS) were created. Inclusion criteria for the presence of IM were endoscopic findings and histological confirmation, while for MetS the ATP III and IDF guidelines. Levels of plasma vascular endothelial growth factor (VEGF) and leptin (Leptin) were determined. VEGF levels were increased in IM (IM vs Control, p=0,011) and IM-MetS groups (IM-MetS vs Control, p <0.001 and IM-MetS vs MetS, p=0.001). Leptin levels were found to be increased in the MetS group (MetS vs. Control, p <0.001 and MetS vs IM, p <0.001) and in IM-MetS (IM-MetS vs Control, p = 0.002, IM-MetS vs IM, p=0.033). Patients with intestinal metaplasia and metabolic syndrome (I M - Me t S g r o u p) have elevated levels of VEGF, while leptin levels were associated predominantly with MetS and not with IM.

Immunohistochemical identification and assessment of the location of leptin, visfatin and chemerin in the liver of men with different body mass index

Background

Adipokines such as leptin, visfatin and chemerin play a pivotal role not only in the pathogenesis of excessive weight gain but also impact on hepatic metabolism. However, alterations in the production of these peptides in the liver of overweight individuals have not been fully elucidated yet. The aim of the study was to evaluate changes in leptin, visfatin and chemerin biosynthesis in the liver of men with different BMI.

Methods

Fourteen adult men without symptoms from the digestive system were recruited. Research material consisted of liver samples. Study participants were divided into two groups: lean (BMI ≤ 25 kg/m²) and overweight subjects (BMI > 25 kg/m²). Paraffin liver sections were processed by immunohistochemistry for detection of leptin, visfatin and chemerin. Hepatic expression of leptin, visfatin and chemerin genes was determined by qRT-PCR method.

Results

Increased immunoreactivity for leptin and chemerin, and decreased immunoreaction for visfatin were observed in the liver of overweight men in comparison to lean subjects. Overweight subjects with hepatic steatosis displayed increased immunoreactivity for leptin and weaker immunoreaction against visfatin and chemerin in the liver, compared to individuals with normal organ structure. Expression of leptin and chemerin was enhanced in the liver of overweight individuals, with the highest expression observed in subjects with hepatic steatosis. Conversely, expression of visfatin in the male liver was decreased in overweight subjects and those with and liver steatosis.

Conclusions

The present study proves that the expression of leptin, visfatin and chemerin in the male liver is altered in overweight individuals. Our report also indicates the potential importance of these peptides in hepatic steatosis associated with overweight.

Role of Leptin and Adiponectin in Endometrial Cancer

Endometrial cancer is the most common malignancy of the female genital tract. Obesity is a strong risk factor for endometrial cancer. Adipose tissue is an active endocrine organ that synthesizes biologically active cytokine peptides, called adipokines. Adiponectin and leptin are the main cytokines of adipose tissue, which may influence the development of metabolic diseases and carcinogenesis. In this scenario, we describe the role of leptin and adiponectin in the development of endometrial cancer. A better understanding of the signalling pathway of these cytokines in endometrial cancerogenesis will provide an opportunity for effective target therapy and may be usable in fertility-sparing treatment. In the future, clinical trials focusing on adipokines, molecular biology, and genetics of the tumour will be needed.

Role of Perinatal Biological Factors in Delayed Lactogenesis II Among Women With Pre-pregnancy Overweight and Obesity

BACKGROUND

Pre-pregnancy overweight and obesity are negatively associated with delayed onset of lactogenesis II (OL), but the mechanisms by which these conditions affect OL are still unclear.

OBJECTIVES

To identify biological factors related to pre-pregnancy overweight/obesity and determine whether these biological factors were associated with delayed OL in this population.

METHODS

In this prospective observational study, we assigned 72 primipara to a pre-pregnancy overweight/obese group (n = 36) and a normal-weight group (n = 36). Blood samples were collected at 37 w of gestation and 48 h postpartum and assayed for levels of the following hormones: leptin, insulin, estradiol, prolactin (PRL), progesterone, and oxytocin. The primary outcome was timing of OL, estimated by maternal perception of breast fullness. We used linear-regression analysis to determine associations between hormones and delayed OL.

RESULTS

Sixty-three participants (87.5%) had complete data. OL occurred later in overweight/obese than in normal-weight women (p < .001). Compared with the normal-weight group, the overweight/obese group showed higher leptin levels at both times of observation and exhibited a slower drop in estrogen concentrations from 37 w of gestation to 48 h postpartum (all p < .05). After adjusting for confounding factors, leptin concentrations in late pregnancy and the magnitudes of decline in estrogen concentrations at 48 h postpartum were correlated with OL.

CONCLUSION

Women who were overweight/obese before pregnancy had elevated leptin levels in late pregnancy and a delayed decline in estrogen concentrations at 48 h postpartum. Both of these phenomena were related to delayed OL in this population.

Molecular cloning and tissue distribution of the leptin gene in gibel carp (Carassius auratus gibelio): Regulation by postprandial and long-term fasting treatment

Leptin is a multifunctional hormone that serves as a feeding regulator in mammals. However, the effect of leptin on fish remains unclear. We sequenced the leptin gene from gibel carp (Carassius auratus gibelio) and designated it gLEP. The length of the gLEP cDNA sequence was 562 bp, including an open reading frame (ORF) of 516 bp. The ORF putatively encodes a peptide of 171 amino acids, including a signal peptide of 20 amino acids. gLEP shared low primary amino acid sequence homology with leptin genes in vertebrates, whereas three-dimensional (3D) structural modeling revealed strong identity with the structures in other vertebrates. gLEP mRNA was widely distributed in all of the tissue that we examined, with the highest levels of expression in the hepatopancreas. Hepatopancreas gLEP mRNA expression levels showed no changes following postprandial treatment. However, hepatopancreas gLEP mRNA expression levels greatly decreased (P < 0.05) after fasting but substantially increased (P < 0.05) after refeeding in the long-term fasting treatment. In summary, these results indicate that leptin expression could be influenced by the regulation of food intake. These results provide the initial step toward elucidating the appetite regulatory systems associated with leptin in gibel carp.

Renal Cell Cancer and Obesity

Cancers are a frequent cause of morbidity and mortality. There are many risk factors for tumours, including advanced age, personal or family history of cancer, some types of viral infections, exposure to radiation and some chemicals, smoking and alcohol consumption, as well as obesity. Increasing evidence suggest the role of obesity in the initiation and progression of various cancers, including renal cell carcinoma. Since tumours require energy for their uncontrollable growth, it appears plausible that their initiation and development is associated with the dysregulation of cells metabolism. Thus, any state characterised by an intake of excessive energy and nutrients may favour the development of various cancers. There are many factors that promote the development of renal cell carcinoma, including hypoxia, inflammation, insulin resistance, excessive adipose tissue and adipokines and others. There are also many obesity-related alterations in genes expression, including DNA methylation, single nucleotide polymorphisms, histone modification and miRNAs that can promote renal carcinogenesis. This review focuses on the impact of obesity on the risk of renal cancers development, their aggressiveness and patients’ survival.

Leptin in Osteoarthritis and Rheumatoid Arthritis: Player or Bystander?

White adipose tissue (WAT) is a specialized tissue whose main function is lipid synthesis and triglyceride storage. It is now considered as an active organ secreting a plethora of hormones and cytokines namely adipokines. Discovered in 1994, leptin has emerged as a key molecule with pleiotropic functions. It is primarily recognized for its role in regulating energy homeostasis and food intake. Currently, further evidence suggests its potent role in reproduction, glucose metabolism, hematopoiesis, and interaction with the immune system. It is implicated in both innate and adaptive immunity, and it is reported to contribute, with other adipokines, in the cross-talking networks involved in the pathogenesis of chronic inflammation and immune-related diseases of the musculo-skeletal system such as osteoarthritis (OA) and rheumatoid arthritis (RA). In this review, we summarize the most recent findings concerning the involvement of leptin in immunity and inflammatory responses in OA and RA.

Sexual Dimorphism in Cardiovascular Biomarkers: Clinical and Research Implications

Sex-based differences in cardiovascular disease presentation, diagnosis, and response to therapies are well established, but mechanistic understanding and translation to clinical applications are limited. Blood-based biomarkers have become an important tool for interrogating biologic pathways. Understanding sexual dimorphism in the relationship between biomarkers and cardiovascular disease will enhance our insights into cardiovascular disease pathogenesis in women, with potential to translate to improved individualized care for men and women with or at risk for cardiovascular disease. In this review, we examine how biologic sex associates with differential levels of blood-based biomarkers and influences the effect of biomarkers on disease outcomes. We further summarize key differences in blood-based cardiovascular biomarkers along central biologic pathways, including myocardial stretch/injury, inflammation, adipose tissue metabolism, and fibrosis pathways in men versus women. Finally, we present recommendations for leveraging our current knowledge of sex differences in blood-based biomarkers for future research and clinical innovation.

Leptin as a key regulator of the adipose organ

Leptin is a hormone primarily produced by the adipose tissue in proportion to the size of fat stores, with a primary function in the control of lipid reserves. Besides adipose tissue, leptin is also produced by other tissues, such as the stomach, placenta, and mammary gland. Altogether, leptin exerts a broad spectrum of short, medium, and long-term regulatory actions at the central and peripheral levels, including metabolic programming effects that condition the proper development and function of the adipose organ, which are relevant for its main role in energy homeostasis. Comprehending how leptin regulates adipose tissue may provide important clues to understand the pathophysiology of obesity and related diseases, such as type 2 diabetes, as well as its prevention and treatment. This review focuses on the physiological and long-lasting regulatory effects of leptin on adipose tissue, the mechanisms and pathways involved, its main outcomes on whole-body physiological homeostasis, and its consequences on chronic diseases.

Correlation of Leptin, Proinflammatory Cytokines and Oxidative Stress with Tumor Size and Disease Stage of Endometrioid (Type I) Endometrial Cancer and Review of the Underlying Mechanisms

Endometrioid endometrial cancer is associated with increased BMI and obesity through multiple pathogenetic mechanisms involving hyperestrogenism, hyperinsulinemia, altered adipokine secretion, inflammation, and oxidative stress. In the present study, we aimed to investigate the correlation between BMI, leptin, the proinflammatory cytokines IL-6 and TNFα, reactive oxygen species (ROS), and the traditional prognostic factors T, G, N and M status among type I endometrioid and type II endometrial cancer patients. We enrolled 305 consecutive endometrial cancer patients prospectively. We found that BMI, leptin, and IL-6 significantly correlated with T status, N status, and M status among endometrioid type I endometrial cancer patients. Among type II endometrial cancer patients, BMI and leptin did not correlate with any of the prognostic parameters, whereas there was a positive correlation between IL-6 and the presence of distant metastases. In the multivariate regression analysis, BMI, leptin, and IL-6 were independent predictive variables of T, N, and M status in endometrioid type I endometrial cancer patients. Our study demonstrates that weight gain, adiposity-related adipokines, inflammation, and oxidative stress correlate with the prognostic factors of endometrioid endometrial cancer. Knowledge of the role of obesity-related biological pathways and mediators in the pathogenesis and prognosis of endometrioid endometrial malignancies may offer new perspectives on combined therapeutic strategies that have not been explored to date, both in the advanced disease and in the adjuvant setting.

Plasma adipocytokines distinguish tuberculous lymphadenitis from pulmonary tuberculosis

Adipocytokines are the major secretory products of adipose tissue and potential markers of metabolism and inflammation. However, their association in host immune response against tuberculous lymphadenitis (TBL) disease is not known. Thus, we measured the systemic levels of adipocytokines in TBL (n = 44) and compared to pulmonary tuberculosis (PTB, n = 44) and healthy control (HC, n = 44) individuals. We also examined the pre and post-treatment adipocytokine levels in TBL individuals upon completion of standard anti-tuberculosis treatment (ATT). The receiver operating characteristics (ROC) were performed between TBL, PTB and HCs to find the potential discriminatory markers. Finally, principal component (PCA) analysis was performed to reveal the expression patterns of adipocytokines among study groups. Our results demonstrate that TBL is associated with significantly higher systemic levels of adipocytokines (except resistin) when compared with PTB and significantly lower levels when compared with HC (except adiponectin) individuals. Upon completion of ATT, the systemic levels of adiponectin and resistin were significantly decreased when compared to pre-treatment levels. Upon ROC analysis, all the three adipocytokines discriminated TBL from PTB but not with HCs, respectively. Similarly, adipocytokines were differentially clustered in TBL in comparison to PTB in PCA analysis. Therefore, adipocytokines are a distinguishing feature in TBL compared to PTB individuals.

Expected and paradoxical effects of obesity on cancer treatment response

Obesity, whose prevalence is pandemic and continuing to increase, is a major preventable and modifiable risk factor for diabetes and cardiovascular diseases, as well as for cancer. Furthermore, epidemiological studies have shown that obesity is a negative independent prognostic factor for several oncological outcomes, including overall and cancer-specific survival, for several site-specific cancers as well as for all cancers combined. Yet, a recently growing body of evidence suggests that sometimes overweight and obesity may associate with better outcomes, and that immunotherapy may show improved response among obese patients compared with patients with a normal weight. The so-called 'obesity paradox' has been reported in several advanced cancer as well as in other diseases, albeit the mechanisms behind this unexpected relationship are still not clear. Aim of this review is to explore the expected as well as the paradoxical relationship between obesity and cancer prognosis, with a particular emphasis on the effects of cancer therapies in obese people.

Leptin Protein Expression and Promoter Methylation in Ovarian Cancer: A Strong Prognostic Value with Theranostic Promises

Ovarian cancer (OC) is the deadliest among all gynecological cancers. Epidemiological studies showed that obesity might influence many cancers including OC. One of the key factors that may link obesity and OC is leptin (LEP), known as an adipokine with pleiotropic effects on body homeostasis. This study aims to investigate the expression pattern of LEP, assess the methylation profiles of LEP and their associations with clinicopathological features including survival outcomes of OC patients. The protein expression of LEP was evaluated in 208 samples using both tissue microarray and immunohistochemistry techniques. The methylation profiles of LEP were measured in 63 formalin-fixed, paraffin-embedded tumor tissues by quantitative polymerase chain reaction using a MethyLight assay. Our results showed a significant association of LEP protein overexpression with several clinicopathological variables, mainly tumor subtype, LVI, age of menarche, tumor size and stage (p < 0.04). Kaplan-Meier analysis (using low expression versus high expression as a discriminator) indicated that LEP protein overexpression is a powerful positive prognosticator of both OC recurrence (DFS) and disease-specific survival (DSS) in our OC cohort (log-rank p = 0.01 and p = 0.002, respectively). This implies that patients with high LEP expression profiles live longer with less recurrence rates. Methylation analysis results demonstrated a clear association between no/low LEP protein expression pattern (38%) and LEP promoter CpG island hypermethylation (43%). Results of this study suggest that LEP is a powerful prognosticator of OC recurrence and DSS. LEP expression in OC seems to be regulated by its promoter hypermethylation through gene partial/total silencing. Further multi-institutional studies using larger cohorts are required to demystify the intricate molecular functions of this leptin-driven effects in OC pathophysiology and to accurately assess its theranostic potential and validate its prognostic/predictive power in OC onset, progression towards more effective and personalized management of OC patients.