Leptin as an important link between obesity and cardiovascular risk factors in men with acute myocardial infarction

Leptin-VEGF crosstalk in excess body mass and related disorders: A systematic review

By 2030, it is expected that a billion people will have suffer from obesity. Adipose tissue synthesizes leptin, an adipokine that affects cardiovascular risk. Leptin intensifies the synthesis of vascular endothelial growth factor (VEGF). Our study reviews recent reports on leptin-VEGF crosstalk in obesity and related disorders. PubMed, Web of Science, Scopus, and Google Scholar were searched. One hundred and one articles involving human, animal, and in vitro research were included. In vitro studies show the crucial role of interaction between endothelial cells and adipocytes and hypoxia as a factor that intensifies leptin's effects on VEGF. Leptin-VEGF crosstalk promotes the progression of cancer. The animal research reveal that a high-fat diet enhances leptin and VEGF crosstalk. Genetic and epigenetic mechanisms and procreator-offspring programming may be involved in leptin-VEGF crosstalk. Some female-specific characteristics of leptin-VEGF relation in obesity were observed. The human studies have shown that increased leptin and VEGF synthesis and leptin-VEGF crosstalk are factors linking obesity with elevated cardiovascular risk. The studies of the last 10 years documented a range of significant aspects of leptin-VEGF crosstalk specific for obesity and related disorders, shedding new light on the link between obesity and increased cardiovascular risk.

Inflammation Related to Obesity in the Etiopathogenesis of Gastroenteropancreatic Neuroendocrine Neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are rare neoplasms, which, due to their heterogeneous nature, non-specific symptoms, and lack of specific tumor markers pose many diagnostic and clinical challenges. In recent years, the effectiveness of GEP-NEN diagnosis has increased, which is probably associated with the greater availability of diagnostic tests and the cooperation of many experienced specialists in various scientific disciplines. In addition to the possible genetic etiology, the cause of GEP-NET development is not fully understood. Inflammation and obesity are known risks that contribute to the development of many diseases. Chronic inflammation accompanying obesity affects the hormonal balance and cell proliferation and causes the impairment of the immune system function, leading to neoplastic transformation. This review explores the role of inflammation and obesity in GEP-NETs. The exact mechanisms inducing tumor growth are unknown; however, the profile of inflammatory factors released in the GEP-NET tumor microenvironment is responsible for the progression or inhibition of tumor growth. Both the excess of adipose tissue and the impaired function of the immune system affect not only the initiation of cancer but also reduce the comfort and lifetime of patients.

Testing Links of Food-Related Olfactory Perception to Peripheral Ghrelin and Leptin Concentrations

The peptide hormones ghrelin and leptin play major roles in the regulation of appetite and food intake. However, the precise effects of these hormones on sensory processing remain a subject of debate, particularly with food related stimuli and its small body of evidence. Here, we test for relationships between ghrelin and leptin levels against olfactory performance with multiple food-related odours. Specifically, a total of 94 Caucasian males were tested for their supra-threshold sensitivity (i.e., d′), intensity, and valence perception to three odour compounds (i.e., vanilla, potato, and dairy odours). These sensory data were then analysed against peripheral ghrelin and leptin levels, both assessed in plasma samples. Participants’ body adiposity measures were also obtained. Results lent strong support to one of our original hypotheses, with ghrelin levels being positively correlated to the supra-threshold sensitivity of the dairy odour, (r = 0.241, p = 0.020), and intensity ratings to most of the food odours tested [dairy (r = 0.216, p = 0.037) and vanilla (r = 0.241, p = 0.020)]. By contrast, peripheral leptin levels were not significantly linked to any of the olfactory measures (p > 0.05). These relationships remained similar after controlling for variabilities of adiposity measures. The present study brings novel insights by identifying positive links between supra-threshold olfactory perception and ghrelin. This new knowledge is highly relevant for future research linking olfactory shifts to hormonal dysregulation and obesity.

Serum levels of leptin and adiponectin in patients with multiple sclerosis

Background

The role of adipokines such as leptin and adiponectin in regulating the immunity has been documented, however data concerning their consequence on multiple sclerosis (MS) Egyptian patients are deficient. The aim of this study is to demonstrate the serum levels of leptin and adiponectin in MS patients and to assess their association with disease disability and severity. A case–control study including 60 subjects (30 MS patients and 30 age, sex and body mass index-matched healthy controls) was performed.

Results

Serum leptin level was significantly higher among MS patients than controls (P < 0.001) while adiponectin was not significantly elevated in MS patients (P = 0.24). There was a significant positive correlation between leptin levels with MS disability (Expanded Disability Status Scale) (r = 0.678; P < 0.001), severity (Multiple Sclerosis Severity Score) (r = 0.631; P < 0.001) and progression (progression index) (r = 0.461; P = 0.01). There was no statistically significant correlation between adiponectin with disease disability, severity or progression.

Conclusions

MS patients had significantly higher serum leptin levels and insignificant adiponectin levels compared to controls. Leptin has a potential role in multiple sclerosis disability and severity. However, adiponectin is not useful as a biomarker of MS disease, disability and severity.

Influence of Obesity on Clinical Manifestations and Response to Therapy in Cutaneous Leishmaniasis Caused by Leishmania braziliensis

BACKGROUND

Cutaneous leishmaniasis (CL) caused by Leishmania braziliensis is characterized by a single ulcer or multiple cutaneous lesions with raised borders. Cure rates <60% are observed in response to meglumine antimoniate therapy. We investigated the impact of obesity on CL clinical presentation and therapeutic response.

METHODS

A total of 90 age-matched patients with CL were included (30 obese, 30 overweight, and 30 with normal body mass index [BMI]). CL was diagnosed through documentation of L. braziliensis DNA by polymerase chain reaction or identification of amastigotes in biopsied skin-lesion samples. Serum cytokine levels were determined by chemiluminescence. Antimony therapy with Glucantime (Sanofi-Aventis; 20 mg/kg/day) was administered for 20 days.

RESULTS

Obese CL patients may present hypertrophic ulcers rather than typical oval, ulcerated lesions. A direct correlation between BMI and healing time was noted. After 1 course of antimony, cure was achieved in 73% of patients with normal BMI, 37% of overweight subjects, yet just 18% of obese CL patients (P < .01). Obese CL cases additionally presented higher leptin levels than overweight patients or those with normal BMI (P < .05).

CONCLUSIONS

Obesity modifies the clinical presentation of CL and host immune response and is associated with greater failure to therapy.

Obesity and inflammation: colorectal cancer engines

The prevalence of obesity continues to increase to the extent that it became a worldwide pandemic. An accumulating body of evidence has associated obesity with the development of different types of cancer, including colorectal cancer, which is a notorious disease with a high mortality rate. At the molecular level, colorectal cancer is a heterogenous disease characterized by a myriad of genetic and epigenetic alterations associated with various forms of genomic instability (detailed in Supplementary Materials). Recently, the microenvironment has emerged as a major factor in carcinogenesis. Our aim is to define the different molecular alterations leading to the development of colorectal cancer in obese patients with a focus on the role of the microenvironment in carcinogenesis. We also highlight all existent molecules in clinical trials that target the activated pathways in obesity-associated colorectal cancer, whether used as single treatments or in combination. Obesity predisposes to colorectal cancer via creating a state of chronic inflammation with dysregulated adipokines, inflammatory mediators, and other factors such as immune cell infiltration. A unifying theme in obesity-mediated colorectal cancer is the activation of the PI3K/AKT, mTOR/MAPK, and STAT3 signaling pathways. Different inhibitory molecules towards these pathways exist, increasing the therapeutic choice of obesity-associated colon cancer. However, obese patients are more likely to suffer from chemotherapy overdosing. Preventing obesity through maintaining a healthy and active lifestyle remains to be the best remedy.

Diabetes Mellitus and Its Metabolic Complications: The Role of Adipose Tissues

Many approaches have been used in the effective management of type 2 diabetes mellitus. A recent paradigm shift has focused on the role of adipose tissues in the development and treatment of the disease. Brown adipose tissues (BAT) and white adipose tissues (WAT) are the two main types of adipose tissues with beige subsets more recently identified. They play key roles in communication and insulin sensitivity. However, WAT has been shown to contribute significantly to endocrine function. WAT produces hormones and cytokines, collectively called adipocytokines, such as leptin and adiponectin. These adipocytokines have been proven to vary in conditions, such as metabolic dysfunction, type 2 diabetes, or inflammation. The regulation of fat storage, energy metabolism, satiety, and insulin release are all features of adipose tissues. As such, they are indicators that may provide insights on the development of metabolic dysfunction or type 2 diabetes and can be considered routes for therapeutic considerations. The essential roles of adipocytokines vis-a-vis satiety, appetite, regulation of fat storage and energy, glucose tolerance, and insulin release, solidifies adipose tissue role in the development and pathogenesis of diabetes mellitus and the complications associated with the disease.

Modulatory Effect of Probiotic Lactobacillus rhamnosus PB01 on Mechanical Sensitivity in a Female Diet-Induced Obesity Model

Obese animals and humans demonstrate higher sensitivity to pain stimuli. Among the endogenous factors prompting obesity, the intestinal microbiota has been proposed to influence responsiveness to pain. The beneficial effects of probiotics on obesity are well documented, whereas data on their analgesic efficacy is minimal. The protective effect of probiotics on nociception in diet-induced obese male mice has been previously demonstrated, but the sex differences in pain sensitivity and analgesic response do not allow for the generalization of these findings to the female gender. Hence, this study aimed at investigating the potential effects of oral probiotic supplementation on mechanical pain thresholds in female diet-induced obese mice compared with controls. Thirty-two adult female mice (N=32) were randomly divided into two groups receiving standard (normal-weight group; NW) or high-fat diet (diet-induced obesity; DIO). All rats received a single daily dose (1 × 109 CFU) of probiotics (Lactobacillus rhamnosus PB01, DSM14870) for four weeks by gavage. Mechanical pain thresholds were recorded by an electronic von Frey device at baseline, at the end of weeks 2, 4, 6, and 8 in both DIO and NW groups with and without consumption of probiotics. Blood samples were obtained for the measurement of lipid profile and reproductive hormone levels. Bodyweight was considerably lower (P < 0.001) in groups supplied with probiotics than groups without probiotics. Pressure pain threshold values showed a significant (P < 0.001) increase (reduced pain sensitivity) following probiotic supplementation, proposing a modulatory effect of probiotics on mechanical sensory circuits and mechanical sensitivity, which might be a direct consequence of weight loss or an indirect result of the probiotics' anti-inflammatory properties. Understanding the precise underlying mechanism for the effect of probiotics on weight loss and mechanical pain sensitivity seen in this study warrants further investigation.

Expression Pattern of Leptin and Its Receptors in Endometrioid Endometrial Cancer

The identification of novel molecular markers and the development of cancer treatment strategies are very important as cancer incidence is still very high. Obesity can contribute to cancer progression, including endometrial cancer. Adipocytes secrete leptin, which, when at a high level, is associated with an increased risk of cancer. The aim of this study was to determine the expression profile of leptin-related genes in the endometrial tissue samples and whole blood of patients. The study material included tissue samples and whole blood collected from 30 patients with endometrial cancer and 30 without cancer. Microarrays were used to assess the expression profile of leptin-related genes. Then, the expression of leptin (LEP), leptin receptor (LEPR), leptin receptor overlapping transcript (LEPROT), and leptin receptor overlapping transcript-like 1 (LEPROTL1) was determined by the Real-Time Quantitative Reverse Transcription Reaction (RT-qPCR). The serum leptin concentration was evaluated using Enzyme-linked immunosorbent assay (ELISA). Leptin and its receptors were overexpressed both at the mRNA and protein levels. Furthermore, there were strong positive correlations between leptin levels and patient Body Mass Index (BMI). Elevated levels of leptin and its receptors may potentially contribute to the progression of endometrial cancer. These observations may be useful in designing endometrial cancer treatment strategies.

Interaction of Obesity and Hypertension on Cardiac Metabolic Remodeling and Survival Following Myocardial Infarction

Background

Obesity and hypertension are risk factors for myocardial infarction (MI); however, their potential interactions on post‐MI outcomes are unclear. We examined interactions of obesity and hypertensionon post‐MI function, remodeling, metabolic changes, and recovery.

Methods and Results

Male and female C57BL/6J mice were provided standard chow or high‐fat/fructose diet for 8 weeks and then infused with angiotensin II for 2 weeks to induce hypertension. MI was then induced by surgical ligation of the left coronary artery for 7 days. Obesity alone did not cause cardiac injury or exacerbate hypertension‐induced cardiac dysfunction. After MI, however, obese‐normotensive mice had lower survival rates compared with chow‐fed mice (56% versus 89% males; 54% versus 75% females), which were further decreased by hypertension (29% males; and 35% females). Surviving obese‐normotensive males displayed less left ventricular dilation and pulmonary congestion compared with chow‐fed males after MI; hypertension reversed left ventricular dilation because of high‐fat/fructose diet and promoted significant pulmonary congestion compared with chow‐fed controls. Obese‐normotensive males displayed higher left ventricular α‐MHC (alpha‐myosin heavy chain) protein, phosphorylated Akt (protein kinase B) and AMPK (adenosine‐monophosphate activated kinase), PPAR‐γ (peroxisome proliferator activated receptor gamma), and plasma adiponectin levels after MI, indicating favorable contractile and metabolic changes. However, these favorable contractile and metabolic changes were attenuated by hypertension. Obese‐hypertensive males also had lower levels of collagen in the infarcted region, indicating decreased ability to promote an adaptive wound healing response to MI.

Conclusions

Obesity reduces post‐MI survival but is associated with improved post‐MI cardiac function and metabolism in surviving normotensive mice. When hypertension accompanies obesity, favorable metabolic pathways associated with obesity are attenuated and post‐MI cardiac function and remodeling are adversely impacted.

Effect of Leptin on Chronic Inflammatory Disorders: Insights to Therapeutic Target to Prevent Further Cardiovascular Complication

In response to obesity-associated chronic inflammatory disorders, adipose tissue releases a biologically active peptide known as leptin. Leptin activates the secretion of chemical mediators, which contribute to the pathogenesis of chronic inflammatory disorders, such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and psoriasis. Conversely, adiposity and obesity are the major aggravating risk factors in the pathogenesis of metabolic syndrome (MetS), including type II diabetes mellitus and obesity-associated hypertension. Elevated level of leptin in obesity-associated hypertension causes an increase in the production of aldosterone, which also results in elevation of arterial blood pressure. Hyperleptinemia is associated with the progress of the atherosclerosis through secretion of pro-inflammatory cytokines, like interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), IL-17, and other cytokines to promote inflammation. The release of those cytokines leads to chronic inflammatory disorders and obesity-associated MetS. Thus, the aberrant leptin level in both MetS and chronic inflammatory disorders also leads to the complication of cardiovascular diseases (CVD). Therapeutic target of leptin regarding its pro-inflammatory effect and dysregulated sympathetic nervous system activity may prevent further cardiovascular complication. This review mainly assesses the mechanism of leptin on the pathogenesis and further cardiovascular risk complication of chronic inflammatory disorders.

Correlation of Leptin With Acute Myocardial Infarction: A Case Control Study

INTRODUCTION

Leptin, a satiety hormone, has the ability to inhibit hunger and is thus, a regulator of body weight. Leptin is also elevated in cardiovascular events such as acute myocardial infarction (AMI) and hence is considered as modifiable risk factors for AMI. The purpose of this study is therefore to investigate the correlation of leptin with AMI.

METHODOLOGY

In this retrospective study, data of patients were taken from the database between January 2017 to December 2019 from a cardiovascular unit of tertiary care hospital in Pakistan. Patients were divided into two groups, based on participants who had suffered from AMI and other groups who had not suffered an AMI. Leptin levels were compared for both groups. Age, body mass index (BMI), and smoking history were noted in a self-structured questionnaire. In addition, mean blood pressure and cholesterol levels were also noted for both groups.

RESULTS

Leptin was significantly higher in patients with first time AMI (29.21 ± 9.21 ng/mL vs. 11.23 ± 3.12 ng/mL: p-value, <0.0001). BMI (27.2 ± 3.2 kg/m2 vs. 24.9 ± 2.8 kg/m2: p-value, <0.0001) and percentage of smokers (40.9% vs. 22.9%: p-value, 0.032) were also significantly higher in patients with AMI.

CONCLUSION

A positive correlation was found between AMI and serum leptin levels in smokers and obese patients. Hence, we suggest that cardiologists should stress upon controlling these modifiable risk factors to reduce the incidence of AMI in the future.

Association of Leptin With Obesity and Insulin Resistance

Introduction

Leptin, a hormone released by the body to regulate energy balance by inhibiting hunger, decreases fat storage in adipocytes. Leptin is thought to play some role in obesity and insulin resistance. In this study, our aim is to see the association of leptin with obesity and insulin resistance.

Methods

This case-control study was conducted in a tertiary care hospital in Pakistan from January 2020 to April 2020. Ninety-two participants with BMI greater than 25 kg/m², with no known comorbidities were enrolled in the study after informed consent. Ninety-two participants, who came to the outpatient department without a history of chronic disease, with BMI less than 25 kg/m² were enrolled as a control group. Data were collected via self-structured questionnaires. Their blood was drawn and sent to the laboratory for cholesterol levels, insulin resistance and leptin levels.

Results

Serum leptin levels (51.24 ± 18.12 vs. 9.10 ± 2.99: p-value, < 0.0001), serum cholesterol levels (198.2 ± 32.1 vs. 151.2 ± 21.2, p-value < 0.0001) and insulin resistance (7.9 ± 2.1 vs. 6.3 ± 1.9, p-value < 0.0001) were higher in obese patients.

Conclusion

As per the results of this study, obesity was associated with increase serum leptin levels and insulin resistance. Further multi-centric studies are required to prove the possible relationship, which might help devise plans to manage obesity.

Temporal Leptin to Determine Cardiovascular and Metabolic Fate throughout the Life

Leptin links peripheral adiposity and the central nervous system (CNS) to regulate cardiometabolic physiology. Within the CNS, leptin receptor-expressing cells are a counterpart to circulating leptin, and leptin receptor-mediated neural networks modulate the output of neuroendocrine and sympathetic nervous activity to balance cardiometabolic homeostasis. Therefore, disrupted CNS leptin signaling is directly implicated in the development of metabolic diseases, such as hypertension, obesity, and type 2 diabetes. Independently, maternal leptin also plays a central role in the development and growth of the infant during gestation. Accumulating evidence points to the dynamic maternal leptin environment as a predictor of cardiometabolic fate in their offspring as it is directly associated with infant metabolic parameters at birth. In postnatal life, the degree of serum leptin is representative of the level of body adiposity/weight, a driving factor for cardiometabolic alterations, and therefore, the levels of blood leptin through the CNS mechanism, in a large part, are a strong determinant for future cardiometabolic fate. The current review focuses on highlighting and discussing recent updates for temporal dissection of leptin-associated programing of future cardiometabolic fate throughout the entire life.

Adipokines and Inflammation: Focus on Cardiovascular Diseases

It is well established that adipose tissue, apart from its energy storage function, acts as an endocrine organ that produces and secretes a number of bioactive substances, including hormones commonly known as adipokines. Obesity is a major risk factor for the development of cardiovascular diseases, mainly due to a low grade of inflammation and the excessive fat accumulation produced in this state. The adipose tissue dysfunction in obesity leads to an aberrant release of adipokines, some of them with direct cardiovascular and inflammatory regulatory functions. Inflammation is a common link between obesity and cardiovascular diseases, so this review will summarise the role of the main adipokines implicated in the regulation of the inflammatory processes occurring under the scenario of cardiovascular diseases.

Plasma proteomic profile of frailty

Frailty is a state of decreased physiological reserve and increased vulnerability to adverse outcomes in aging, and is characterized by dysregulation across various biological pathways. Frailty may manifest biologically as alteration in protein expression, possibly regulated at genetic, transcriptional and epigenetic levels. In this study, we examined the proteomic profile associated with frailty defined by an established cumulative frailty index (FI). Using the SomaScan® assay, 4265 proteins were measured in plasma, of which 55 were positively associated and 88 were negatively associated with the FI. The proteins most strongly associated with frailty were fatty acid-binding proteins, including fatty acid-binding protein (FABP) (p = 1.96 × 10-19 ) and FABPA (p = 8.10 × 10-16 ), leptin (p = 1.43 × 10-14 ), and ANTR2 (p = 7.95 × 10-20 ). Pathway analysis with the top 143 frailty-associated proteins revealed enrichment for proteins in pathways related to lipid metabolism, musculoskeletal development and function, cell-to-cell signaling and interaction, cellular assembly, and organization. Frailty prediction model constructed with elastic net regression utilizing 110 proteins demonstrated a correlation between predicted frailty and observed frailty (r = 0.57, p < 2.2 × 10-16 ). Predicted frailty was also more strongly correlated with chronological age (r = 0.54, p < 2.2 × 10-16 ) than observed frailty (r = 0.37, p = 1.2 × 10-15 ). This study identified novel proteins and pathways related to frailty that may offer improved frailty phenotyping and prediction.

Molecular Mechanisms of Adiponectin-Induced Attenuation of Mechanical Stretch-Mediated Vascular Remodeling

Hypertension induces vascular hypertrophy, which changes blood vessels structurally and functionally, leading to reduced tissue perfusion and further hypertension. It is also associated with dysregulated levels of the circulating adipokines leptin and adiponectin (APN). Leptin is an obesity-associated hormone that promotes vascular smooth muscle cell (VSMC) hypertrophy. APN is a cardioprotective hormone that has been shown to attenuate hypertrophic cardiomyopathy. In this study, we investigated the molecular mechanisms of hypertension-induced VSMC remodeling and the involvement of leptin and APN in this process. To mimic hypertension, the rat portal vein (RPV) was mechanically stretched, and the protective effects of APN on mechanical stretch-induced vascular remodeling and the molecular mechanisms involved were examined by using 10 μg/ml APN. Mechanically stretching the RPV significantly decreased APN protein expression after 24 hours and APN mRNA expression in a time-dependent manner in VSMCs. The mRNA expression of the APN receptors AdipoR1, AdipoR2, and T-cadherin significantly increased after 15 hours of stretch. The ratio of APN/leptin expression in VSMCs significantly decreased after 24 hours of mechanical stretch. Stretching the RPV for 3 days increased the weight and [³H]-leucine incorporation significantly, whereas APN significantly reduced hypertrophy in mechanically stretched vessels. Stretching the RPV for 10 minutes significantly decreased phosphorylation of LKB1, AMPK, and eNOS, while APN significantly increased p-LKB1, p-AMPK, and p-eNOS in stretched vessels. Mechanical stretch significantly increased p-ERK1/2 after 10 minutes, whereas APN significantly reduced stretch-induced ERK1/2 phosphorylation. Stretching the RPV also significantly increased ROS generation after 1 hour, whereas APN significantly decreased mechanical stretch-induced ROS production. Exogenous leptin (3.1 nM) markedly increased GATA-4 nuclear translocation in VSMCs, whereas APN significantly attenuated leptin-induced GATA-4 nuclear translocation. Our results decipher molecular mechanisms of APN-induced attenuation of mechanical stretch-mediated vascular hypertrophy, with the promising potential of ultimately translating this protective hormone into the clinic.

Pro-inflammatory Cytokines in Acute Coronary Syndromes

BACKGROUND

Over the last decades, the role of inflammation and immune system activation in the initiation and progression of coronary artery disease (CAD) has been established.

OBJECTIVES

The study aimed to present the interplay between cytokines and their actions preceding and shortly after ACS.

METHODS

We searched in a systemic manner the most relevant articles to the topic of inflammation, cytokines, vulnerable plaque and myocardial infarction in MEDLINE, COCHRANE and EMBASE databases.

RESULTS

Different classes of cytokines (intereleukin [IL]-1 family, Tumor necrosis factor-alpha (TNF-α) family, chemokines, adipokines, interferons) are implicated in the entire process leading to destabilization of the atherosclerotic plaque, and consequently, to the incidence of myocardial infarction. Especially IL-1 and TNF-α family are involved in inflammatory cell accumulation, vulnerable plaque formation, platelet aggregation, cardiomyocyte apoptosis and adverse remodeling following the myocardial infarction. Several cytokines such as IL-6, adiponectin, interferon-γ, appear with significant prognostic value in ACS patients. Thus, research interest focuses on the modulation of inflammation in ACS to improve clinical outcomes.

CONCLUSION

Understanding the unique characteristics that accompany each cytokine-cytokine receptor interaction could illuminate the signaling pathways involved in plaque destabilization and indicate future treatment strategies to improve cardiovascular prognosis in ACS patients.

The Role of Leptin Levels in Adaptation to Cold Climates

Currently, adipose tissue is considered an endocrine organ that produces hormone-active substances, including leptin, which can play a key role in thermoregulation processes. Therefore, we performed a meta-analysis to investigate the influence of the climatic environment on leptin levels. A systematic literature search in the databases was carried out on 10 January 2020. Finally, 22 eligible articles were included in the current meta-analysis and a total of 13,320 participants were covered in the final analysis. It was shown that males of the “North” subgroup demonstrated significantly higher levels of leptin (10.02 ng/mL; CI: 7.92–12.13) than males of the “South” subgroup (4.9 ng/mL; CI: 3.71–6.25) (p = 0.0001). On the contrary, in the female group, a similar pattern was not detected (p = 0.91). Apparently, in order to maintain body temperature, higher leptin levels are required. The results of the study indicate that such effects are most pronounced in males and to a smaller extent in females, apparently due to a relatively high initial concentration of leptin in females. The correlation between leptin levels and climatic environment data support the hypothesis of leptin-mediated thermoregulation as an adaptive mechanism to cold climates.

Role of Leptin in Acute Ischemic Stroke

Purpose

Leptin has been implicated as a pathogenetic contributor to atherosclerosis. We aimed to investigate the association of leptin level with ischemic stroke.

Materials and Methods

We prospectively enrolled 52 patients with acute ischemic stroke and measured leptin levels and compared with age- and sex-matched healthy controls. Risk factors, body mass index (BMI), biochemical parameters, intima-media thickness (IMT) on carotid vertebral Doppler and neuroimaging was done. Data were entered into MS-Excel and appropriate statistical analysis was done using SPSS software version 21.0. P = 0.05 was considered statistically significant.

Results

Serum leptin was significantly elevated in stroke patients (6598.1 ± 1035.1) compared to controls (3090.7 ± 698.86) (P < 0.01). Patients had higher BMI (26.9 ± 1.7) than controls (26.9 ± 1.7) (P < 0.00). BMI, total cholesterol, low-density lipoprotein (LDL) cholesterol, white blood cell (WBC) count, erythrocyte sedimentation rate (ESR), and C reactive protein (CRP) were significantly elevated in stroke patients than controls. Correlation analysis among patient group showed that serum leptin positively correlated with CRP (r - 0.41, P - <0.05), WBCs (r - 0.28, P - <0.05), ESR (r - 0.429, P - <0.01) total cholesterol (r - 0.31, P - <0.05), LDL-cholesterol (r - 0.19, P - <0.05), and IMT (r - 0.714, P - <0.001).

Conclusion

Our study showed high leptin levels in patients with stroke. Stroke patients with high leptin had higher BMI and inflammatory markers. The results of our study indicate that leptin may have a role in atherosclerosis mediated through inflammation. Future research should be directed toward understanding the role of leptin in the pathogenesis of cerebrovascular diseases and its potential role in preventive treatment of ischemic stroke.

Effect of an 8-Week Individualized Training Program on Blood Biomarkers, Adipokines and Endothelial Function in Obese Young Adolescents with and without Metabolic Syndrome

Obesity is a chronic condition whose incidence is growing due to lack of exercise and frequent nutrition disorders. Childhood obesity has reached epidemic proportions worldwide. One of the best treatment methods is physical training. However, conflicting results have been reported regarding its clinical effectiveness. These contrasting findings may be due to the type and intensity of the adopted physical training program. Therefore, the purpose of the current study was to investigate the effect of an 8-week individualized physical training program on endothelial function, blood biomarkers and adipokine levels in obese adolescents with and without metabolic syndrome (MS). One-hundred-and-twenty-two obese adolescents (71 obese without MS and 51 obese with MS) aged 14 ± 2 years were included in this study. The 8-week individualized training program decreased glucose, triglycerides, total cholesterol, low-density lipoprotein cholesterol and leptin in obese subjects with and without MS. However, adiponectin and endothelial-dependent vasodilatation increased in the follow-up study in both groups. Taken together, the findings suggest that individualized training program is an effective means for the treatment of obesity and MS in pediatric populations.

Decreasing serum homocysteine and hypocholesterolemic effects of Bovine lactoferrin in male rat fed with high-cholesterol diet

Introduction: Lipid metabolism disorder or hyperlipidemia is known as a risk factor for cardiovascular disease, the increase in serum homocysteine and leptin are associated with atherosclerotic disease. The purpose of the present study was to examine the effects of bovine lactoferrin (bLF) on serum homocysteine (Hcy), apolipoproteinA-I (ApoA-I) and B (ApoB), leptin and lipid profile changes in high-cholesterol-diet (HCD) fed rats.

Methods: The Healthy Adult Sprague-Dawley (SD) male rats were randomly assigned into three experimental groups. Each group consisted of eleven male rats including control group, HCD rats and hypercholesterolemic rats, which were treated with bLF (HCD+bLF). bLF was given by gavage (200 mg/kg/d). After 4 weeks of feeding and overnight fasting, total blood samples were collected.

Results: The results showed the elevated level of Hcy, leptin, total cholesterol, low density lipoprotein cholesterol (LDL-C), ApoB and decrease in ApoA-I in non-treated HCD group compared to the control rats. Administration of bLF significantly ameliorated the Hcy and leptin levels with decrease in LDL-C and total cholesterol in rats fed with a high-cholesterol diet. bLF also tended to increase low serum concentration of ApoA-I and high density lipoprotein cholesterol (HDL-C) in HCD rats. Meanwhile, upon bLF-treated rats, there was a significant decrease in ApoB in HCD group.

Conclusion: The findings indicated that bLF can improve the alteration of serum Hcy, leptin, apolipproteins and lipid changes in male rats fed with high-cholesterol diet. So, bLF can counteract with HCD elicited hyper-homocysteinemia and hyper-leptinemia, suggesting it to have the useful therapeutic potential in patients with atherosclerosis and lipid disorder.