Leptin Receptor Research Articles

MRNA expression profiling of leptin and adiponectin and its receptors in colorectal carcinoma – Biomarker development

BackgroundMetastatic colorectal carcinoma (CRC) is one of the leading causes of mortality of colorectal CRC. Very few prognostic markers and factors affecting progression are studied between metastatic CRC and early CRC. Adipokines are speculated to be associated with this area of interest. In the current study leptin, leptin receptor (Ob-R), adiponectin, adiponectin R1, and adiponectin R2 expression were measured at gene levels to determine a possible association between adipokines and early/metastatic cancer to ultimately identifying a definitive diagnostic marker. Materials and methodsTissue samples were obtained from 62 patients with radical specimens of CRC. Genes expression was determined by Quantitative Reverse-Transcription Polymerase Chain Reaction (qRT-PCR). The association between the clinicopathological parameters and gene expression levels were analyzed by statistical analysis. ResultsOverexpression of leptin mRNA is observed in small tumors (size< 5 cms) (P<0.05).b. Leptin receptor were overexpressed in advanced tumors (1.013 ± 0.152) than early tumors (0.453 ± 0.131). c.Adiponectin expression was higher in early tumors (1.535 ± 0.406) than in advanced tumors (0.48 ± 0.148). d. Distant organ metastasis shows under-expression of adipoR1. e.Overexpression of adipoR2 is seen in small (size<5 cms) (P<0.05) tumors. ConclusionLEPR is better indicator of advancement of tumor than Leptin. ADIPOR1 is a better indicator in advanced CRC than ADIPOR2 and ADIPOQ.

The Potential Role of Leptin in the Regulation of Maternal Weight during Pregnancy and Its Impact on Neonate Weight and Apgar

Leptin is secreted by adipose tissue and expressed in several organs, including the placenta. We investigated the influence of leptin in maternal blood on leptin expression and concentration in the placenta and umbilical cord and its influence on fetal weight and conditions at the time of birth. Twenty-five parturients were recruited, and after childbirth, placental tissue fragments, umbilical arteries, and vein blood were collected. According to leptin concentration in maternal peripheral blood, parturients were divided into low and high leptin groups. Mothers in the high-leptin group had higher age, pre-pregnancy weight, pre-pregnancy BMI, and weight in late pregnancy than mothers in the low-leptin group. Children of mothers in the high-leptin group presented an Apgar score modestly lower than those of the low-leptin group. No differences were observed in leptin concentrations in the umbilical artery and vein. However, the leptin retained in the fetus increased in the high-leptin group compared to the low-leptin group. We observed a negative correlation between fetal leptin retained and maternal age in the low-leptin group. In the high-leptin group, placental leptin concentration was positively correlated with maternal weight in late pregnancy. Nonetheless, the expression of the leptin receptor (Ob-Rb) was negatively correlated with newborn length. In conclusion, this study found a positive correlation between maternal leptin levels and maternal pre-pregnancy weight, BMI, and fetal birth weight. These findings suggest a potential role of leptin in maternal weight regulation during pregnancy and fetal growth.

Revisiting the Effect of Leptin on Alzheimer Disease and Parkinson Disease: The Role of Insulin Sensitivity.

Studies have indicated a link between leptin, Alzheimer disease (AD), and Parkinson disease (PD). However, the causal relationship among them remains not well established due to confounders and reverse causation. This Mendelian randomization (MR) study was performed to evaluate the impact and potential mechanism of leptin and its soluble receptor on AD and PD. Utilizing genome-wide association studies summary-level data, a comprehensive MR was conducted to assess the causal effect of leptin and soluble leptin receptor (sLEPR) on AD and PD. Additionally, we also explored the role of body mass index (BMI) and insulin sensitivity index (ISI) in using the multivariable MR. The primary analysis was performed using the inverse variance-weighted method. Pooled estimates showed that genetically proxied higher leptin levels was significantly associated with a decreased risk of AD (OR 0.838, 95% CI 0.741-0.948, P = .005), but not PD. In contrast, no significant associations were observed between sLEPR levels, AD, and PD. Moreover, the effect of leptin on AD was attenuated to null after adjustment of ISI (OR 0.879, 95% CI 0.758-1.018, P = .086), but not BMI. There was no causal impact of AD and PD on circulating levels of leptin and sLEPR, indicating the absence of reverse causation. Sensitivity analyses confirmed the robustness of these associations, with no obvious pleiotropy and heterogeneity. The study offers evidence supporting a potential protective effect of leptin in AD, but not PD, via the enhancement of insulin sensitivity. Our findings underscore the distinct roles of leptin in AD and PD.

Pilot Study of the DRD3, GHRL, FTO, LEPR, INSIG2, GSTP1, and ABCB1 Gene Expression in Peripheral Blood Leukocytes in Schizophrenic Patients with Metabolic Syndrome

—Many individuals with schizophrenia also suffer from metabolic syndrome (MetS), which is a major risk factor for the development of cardiovascular disroders associated with a heavy burden of disease, as well as with premature death of patients. This study investigated the expression of 7 genes potentially important for the development of metabolic syndrome. QuantiGene Plex 2.0 technology was used to measure how 7 studied genes (DRD3, GHRL, FTO, LEPR, INSIG2, GSTP1, and ABCB1 (MDR1)) were expressed in leukocytes in 60 recently admitted patients with schizophrenia who had been on treatment with antipsychotic drugs. The preliminary results of our study show a change in the expression of the FTO gene in schizophrenic males with metabolic disorders, however, further studies are needed to determine the role of disturbances in the expression of this gene in the development of the metabolic syndrome in patients with schizophrenia.

The Association of Leptin Receptor Gene Q223R Polymorphism with Obesity in the Yakut Population

Background: This study aimed to compare the frequencies of alleles and genotypes of the LEPR Q223R SNP in the Yakut population in samples with normal BMI and obesity and compare the data obtained with other populations worldwide. Methods and Results: The study included 336 DNA samples from volunteers of Yakut nationality (117 women and 219 men) without chronic diseases, whose average age was 47.4±0.06 years. All volunteers were divided into two groups: Group 1 (n=151) with normal BMI and Group 2 (n=185) with obesity. Group 2 was divided into two subgroups: Group 2A (n=156) with BMI ≥30 kg/m2 plus OA and Group 2B (n=29) with BMI ≥30 kg/m2 and without abdominal obesity.The study of the LEPR Q223R SNP was performed using the PCR-RFLP method. The frequency of the G allele of the LEPR Q223R SNP was 79.5% in Group 1 and 82.7% in Group 2. Analysis showed a high frequency of genotype GG: 64.2% and 69.7% in Group 1 and Group 2, respectively. The frequency of the GA genotype was 30.5% in Group 1 and 25.9% in Group 2.The frequency of alleles and genotypes does not differ in the sample of Yakuts with normal BMI and those with obesity. There are also no differences in the frequency of alleles and genotypes based on gender and the presence of abdominal obesity.The high frequency of the G allele in the Yakut population is close to that observed in East Asian populations (86.9%). There was no statistical difference in allele frequencies in comparison with the populations of Han Chinese from Beijing, Japanese from Tokyo, and Vietnamese from Ho Chi Minh City. In European, African, American, and South Asian populations, the G allele occurs with a frequency of 43.7% to 59.2%. Conclusion: The LEPR Q223R SNP does not affect BMI in the Yakut population. In this study, Q223R allele frequencies were like allele frequencies in East Asian populations but not in Caucasians, reflecting racial diversity in the allele distribution of this polymorphism.

Temporal and region-specific tau hyperphosphorylation in the medulla and forebrain coincides with development of functional changes in male obese Zucker rats.

Metabolic syndrome (MetS) is associated with development of tauopathies that contribute to cognitive decline. Without functional leptin receptors, male obese Zucker rats (OZRs) develop MetS, and they have increased phosphorylated tau (ptau) with impaired cognitive function. In addition to regulating energy balance, leptin enhances activation of the hippocampus, which is essential for spatial learning and memory. Whether spatial learning and memory are always impaired in OZRs or develop with MetS is unknown. We hypothesized that male OZRs develop MetS traits that promote regional increases in ptau and functional deficits associated with those brain regions. In the medulla and cortex, tau-pSer199,202 and tau-pSer396 were comparable in juvenile (7-8 wk old) lean Zucker rats (LZRs) and OZRs but increased in 18- to 19-wk-old OZRs. Elevated tau-pSer396 was concentrated in the dorsal vagal complex of the medulla, and by this age OZRs had hypertension with increased arterial pressure variability. In the hippocampus, tau-pSer199,202 and tau-pSer396 were still comparable in 18- to 19-wk-old OZRs and LZRs but elevated in 28- to 29-wk-old OZRs, with emergence of deficits in Morris water maze performance. Comparable escape latencies observed during acquisition in 18- to 19-wk-old OZRs and LZRs were increased in 28- to 29-wk-old OZRs, with greater use of nonspatial search strategies. Increased ptau developed with changes in the insulin/phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway in the hippocampus and cortex but not medulla, suggesting different underlying mechanisms. These data demonstrate that leptin is not required for spatial learning and memory in male OZRs. Furthermore, early development of MetS-associated autonomic dysfunction by the medulla may be predictive of later hippocampal dysfunction and cognitive impairment.NEW & NOTEWORTHY Male obese Zucker rats (OZRs) lack functional leptin receptors and develop metabolic syndrome (MetS). At 16-19 wk, OZRs are insulin resistant, with increased ptau in dorsal medulla and impaired autonomic regulation of AP. At 28-29 wk OZRs develop increased ptau in hippocampus with deficits in spatial learning and memory. Juvenile OZRs lack elevated ptau and these deficits, demonstrating that leptin is not essential for normal function. Elevated ptau and deficits emerge before the onset of diabetes in insulin-resistant OZRs.

A high salt intake in early life affects stress-coping response in males but not in female rats

Eating diets high in salt has been associated with alterations in the immune system and the potential development of neuropsychiatric disorders. This area of research shows promise, but there is currently a limited amount of research on this topic. The present study investigated whether a high salt diet (HSD) affects anhedonia and stress-coping response behaviors in young male and female Wistar rats. In this study, male and female Wistar rats were fed an HSD (8 % NaCl w/w) from weaning to post-natal day (PND) 64. From PND 60 to 64, the rats underwent a spontaneous locomotor activity test (SLA), sucrose splash test (SST), sucrose preference test (SPT), and forced swim test (FST), followed by euthanasia at PND 65. Male and female rats consuming the HSD exhibited an increase in water intake compared to the corresponding control diet (CD) groups. Male rats had lower body weight despite having similar food intakes compared to the CD group. Male rats displayed an active stress-coping behavior in the FST, characterized by increased mobility. Additionally, HSD-fed males exhibited a greater preference for sucrose solution in the SPT. However, no effect of diet and sex were detected in the SST and the SLA, and hypothalamic levels of leptin and ghrelin receptors. On the other hand, female rats were less susceptible to the experimental conditions applied in this protocol than males.

Influence of leptin and its receptors on individuals under chronic social stress behavior.

Stress is the body's physiological reaction to a dangerous or threatening situation, leading to a state of alertness. This reaction is necessary for developing an effective adaptive response to stress and maintaining the body's homeostasis. Chronic stress, caused mainly by social stress, is what primarily affects the world's population. In the last decades, the emergence of psychological disorders in humans has become more frequent, and one of the symptoms that can be observed is aggressiveness. In the brain, stress can cause neuronal circuit alterations related to the action of hormones in the central nervous system. Leptin, for example, is a hormone capable of acting in brain regions and neuronal circuits important for behavioral and emotional regulation. This study investigated the correlation between chronic social stress, neuroendocrine disorders, and individual behavioral changes. Then, leptin and its receptors' anatomical distribution were evaluated in the brains of mice subjected to a protocol of chronic social stress. The model of spontaneous aggression (MSA) is based on grouping young mice and posterior regrouping of the same animals as adults. According to the regrouping social stress, we categorized the mice into i) harmonic, ii) attacked, and iii) aggressive animals. For leptin hormone evaluation, we quantified plasma and brain concentrations by ELISA and evaluated its receptor and isoform expression by western blotting. Moreover, we verified whether stress or changes in leptin levels interfered with the animal's body weight. Only attacked animals showed reduced plasma leptin concentration and weight gain, besides a higher expression of the high-molecular-weight leptin receptor in the amygdala and the low-molecular-weight receptor in the hippocampal region. Aggressive animals showed a reduction in the cerebral concentration of leptin in the hippocampus and a reduced high-and low-molecular-weight leptin receptor expression in the amygdala. The harmonic animals showed a reduction in the cerebral concentration of leptin in the pituitary and a reduced expression of the high-molecular-weight leptin receptor in the amygdala. We then suggest that leptin and its receptors' expression in plasma and specific brain areas are involved in how individuals react in stressful situations, such as regrouping stress in MSA.

Does hypoleptinemia trigger entrapment in anorexia nervosa? Etiological and clinical considerations.

Based on the recent observation that human recombinant leptin (r-Met-hu-leptin; metreleptin) may induce a profound alleviation of the complex symptomatology of patients with anorexia nervosa (AN), we examine the implications for our conceptualisation of this eating disorder. Hypoleptinemia as a core endocrine feature of AN serves as a central and peripheral trigger of tissue-specific adaptations to starvation. In this narrative review, we argue that leptin deficiency may explain many of the puzzling features of this eating disorder. Weight loss can be viewed as a two-step process, with only the second step entailing hypoleptinemia and thereby the entrapment characteristic of AN. We discuss the central and peripheral distribution of leptin receptors and consider possible functional implications of hypoleptinemia. We contrast the slow psychological recovery of patients with AN and of people who experienced starvation upon weight recovery with the rapid onset of improvements upon off-label metreleptin treatment. Characteristics of the sex and age dependent secretion of leptin may contribute to the elevated vulnerability of young females to develop AN.

Leptin receptor deficiency impedes metabolic surgery related-weight loss through inhibition of energy expenditure in db/db mice

BackgroundRoux-en-Y gastric bypass (RYGB) surgery is an effective metabolic surgery against diabetes and obesity. Clinical evidence indicates that patients with severe obesity have a poor curative effect in losing weight if they suffer from leptin or its receptor deficiency, but the underlying mechanism remains elusive. Here, we investigated the effect of leptin receptor deficiency on metabolic dysfunction in db/db mice treated by RYGB surgery.MethodsThe db/db mice and their heterozygote control db/m mice were subjected to RYGB or sham surgery. Body weight, blood glucose, food intake and glucose tolerance were evaluated. Micro-PET/CT and histological analysis were performed to examine the glucose uptake of tissues and the fat changes in mice. The key factors in glucose and fatty acid metabolism were detected by western blot analysis.ResultsCompared with the sham group, the db/db mice in the RYGB group showed more significant weight regain after surgical recovery and improvement in hyperinsulinemia and glucose tolerance. However, the total body fat and multiple organ lipid deposition of RYGB-treated db/db mice was increased. The underlying mechanism studies suggested that the activation of AMPK regulated GLUT4 to increase glucose uptake, but AMPK could not promote fatty acid oxidation through the JAK2/STAT3 pathway under leptin receptor deficiency in db/db mice.ConclusionWe conclude that leptin receptor deficiency impedes the AMPK activation-mediated fat catabolism but does not affect AMPK-related glucose utilization after metabolic surgery in db/db mice. This result helps select surgical indications for patients with obesity and diabetes.

Pain/Stress, Mitochondrial Dysfunction, and Neurodevelopment in Preterm Infants

Introduction: Preterm infants experience tremendous early life pain/stress during their neonatal intensive care unit (NICU) hospitalization, which impacts their neurodevelopmental outcomes. Mitochondrial function/dysfunction may interface between perinatal stress events and neurodevelopment. Nevertheless, the specific proteins or pathways linking mitochondrial functions to pain-induced neurodevelopmental outcomes in infants remain unidentified. Our study aims to investigate the associations among pain/stress, proteins associated with mitochondrial function/dysfunction, and neurobehavioral responses in preterm infants. Methods: We conducted a prospective cohort study, enrolling 33 preterm infants between September 2017 and July 2022 at two affiliated NICUs located in Hartford and Farmington, CT. NICU Network Neurobehavioral Scale (NNNS) datasets were evaluated to explore potential association with neurobehavioral outcomes. The daily pain/stress experienced by infant’s during their NICU stay was documented. At 36–38 weeks post-menstrual age (PMA), neurobehavioral outcomes were evaluated using the NNNS and buccal swabs were collected for further analysis. Mass spectrometry-based proteomics was conducted on epithelial cells obtained from buccal swabs to evaluate protein expression level. Lasso statistical methods were conducted to study the association between protein abundance and infants’ NNNS summary scores. Multiple linear regression and Gene Ontology (GO) enrichment analyses were performed to examine how clinical characteristics and neurodevelopmental outcomes may be associated with protein levels and underlying molecular pathways. Results: During NICU hospitalization, preterm premature rupture of membrane (PPROM) was negatively associated with neurobehavioral outcomes. The protein functions including leptin receptor binding activity, glutathione disulfide oxidoreductase activity and response to oxidative stress, lipid metabolism, and phosphate and proton transmembrane transporter activity were negatively associated with neurobehavioral outcomes; in contrast, cytoskeletal regulation, epithelial barrier, and protection function were found to be associated with the optimal neurodevelopmental outcomes. In addition, mitochondrial function-associated proteins including SPRR2A, PAIP1, S100A3, MT-CO2, PiC, GLRX, PHB2, and BNIPL-2 demonstrated positive association with favorable neurodevelopmental outcomes, while proteins of ABLIM1, UNC45A, keratins, MUC1, and CYB5B showed positive association with adverse neurodevelopmental outcomes. Conclusion: Mitochondrial function-related proteins were observed to be associated with early life pain/stress and neurodevelopmental outcomes in infants. Large-scale studies with longitudinal datasets are warranted. Buccal proteins could be used to predict potential neurobehavioral outcomes.

The temporal and spatial pattern of leptin receptor-expressing cells in the developing mouse hypothalamus.

The arcuate nucleus is a crucial hypothalamic brain region involved in regulating body weight homeostasis. Neurons within the arcuate nucleus respond to peripheral metabolic signals, such as leptin, and relay these signals via neuronal projections to brain regions both within and outside the hypothalamus, ultimately causing changes in an animal's behaviour and physiology. There is a substantial amount of evidence to indicate that leptin is intimately involved with the postnatal development of arcuate nucleus melanocortin circuitry. Further, it is clear that leptin signalling directly in the arcuate nucleus is required for circuitry development. However, as leptin receptor long isoform (Leprb) mRNA is expressed in multiple nuclei within the developing hypothalamus, including the postsynaptic target regions of arcuate melanocortin projections, this raises the possibility that leptin also signals in these nuclei to promote circuitry development. Here, we used RT-qPCR and RNAscope® to reveal the spatio-temporal pattern of Leprb mRNA in the early postnatal mouse hypothalamus. We found that Leprb mRNA expression increased significantly in the arcuate nucleus, ventromedial nucleus and paraventricular nucleus of the hypothalamus from P8, in concert with the leptin surge. In the dorsomedial nucleus of the hypothalamus, increases in Leprb mRNA were slightly later, increasing significantly from P12. Using duplex RNAscope®, we found Leprb co-expressed with Sim1, Pou3f2, Mc4r and Bdnf in the paraventricular nucleus at P8. Together, these data suggest that leptin may signal in a subset of neurons postsynaptic to arcuate melanocortin neurons, as well as within the arcuate nucleus itself, to promote the formation of arcuate melanocortin circuitry during the early postnatal period.

Impact of In Ovo Leptin Injection and Dietary Protein Levels on Ovarian Growth Markers and Early Folliculogenesis in Post-Hatch Chicks (Gallus gallus domesticus).

Genetically bred for rapid growth, broiler breeder hens develop obesity and ovarian dysfunction when fed ad libitum, resembling a condition that resembles human polycystic ovary syndrome (PCOS). Nutritional control applies to post-hatched chicks from one week onward to prevent the development of a PCOS-like phenotype in adult broilers. This study investigated the impact of a growth marker, leptin, and post-hatch nutritional intake on early-life ovarian function. Fertile broiler eggs were injected in ovo with physiological saline solution or 5 µg of leptin and then incubated. After hatching, female chicks were fed ad libitum a diet containing low protein (17% low crude protein (LP)) or standard protein (22% standard crude protein (SP)). Tissues were collected from 7- and 28-day-old chicks for RT-qPCR and histological analysis. In contrast to the LP diet, the SP diet suppressed the mRNA expression of ovarian growth markers essential for folliculogenesis in post-hatched chicks. Leptin injection did not influence ovarian growth markers but increased pituitary gonadotropin transcripts in 7-day-old chicks fed with LP diet. No treatment effects on follicle activation were noted on day 7, but by day 28, in ovo leptin-treated LP-fed chicks exhibited a higher percentage of primary follicles. These changes may have resulted from the early upregulation of genes by leptin during the first week, including pituitary gonadotropins and ovarian leptin receptors. The decline in ovarian growth markers with the SP diet highlights the importance of precise post-hatch protein calculation, which may influence future ovarian function in animals. These findings may contribute to future dietary strategies to enhance broiler reproduction.

Leptin Receptor Deficiency Impairs Lymph Node Development and Adaptive Immune Response.

Activation and clonal expansion of the Ag-specific adaptive immune response in the draining lymph node is essential to clearing influenza A virus infections. Activation sufficient for virus clearance is dependent on the lymph node's architectural organization that is maintained by stromal cells, chiefly fibroblastic reticular cells. During an analysis of influenza A virus clearance in leptin receptor knockout (DB/DB) mice, we observed that the DB/DB mice have markedly reduced numbers of lymph node fibroblastic reticular cells at the steady state. The reduction in lymph node fibroblastic reticular cells resulted in abnormal lymph node organization and diminished numbers of adaptive immune cells in the lymph nodes under homeostatic conditions. As a consequence, the DB/DB mice were impaired in their ability to generate an effective influenza-specific adaptive immune response, which prevented virus clearance. Using leptin receptor mutant mice with point mutations at distinct signaling sites in the leptin receptor, we were able to link the leptin receptor's signaling domain tyrosine 985, which does not contribute to obesity, to lymph node fibroblastic reticular cell development and function. These results demonstrate a novel role for leptin receptor signaling in regulating lymph node development in a manner that is crucial to the generation of Ag-specific adaptive immune responses.

Leptin and Leptin Receptor Polymorphisms in Infants and Their Parents: Correlation with Preterm Birth.

It has been proven that single-nucleotide polymorphisms (SNPs) in LEP and LEPR genes could predispose individuals to an increased risk of pregnancy adverse outcomes (PAOs) such as recurrent pregnancy loss (RPL) and pre-eclampsia. Preterm birth (PTB) is the leading cause of infant mortality. We decided to investigate the correlation between PTB and LEP and LEPR SNPs. The study cohort included families who underwent spontaneous PTB and control samples of families who had at-term-born (≥37 weeks of gestational age) children. Swabs were performed by rubbing the sticky end for about 30 s on the gum and on the inside of the cheek, allowing us to collect the flaking cells of the oral mucosa. Genotyping of the three SNPs-LEPRA668G, LEPG2548A and A19G-was carried out via an ARMS-MAMA real-time PCR procedure, as previously described. Regarding LEPG2548A, we found that the most expressed genotype in infants both in the preterm and the at-term group was AG; however, we did not discover any statistically significant difference (p = 0.97). Considering LEPA19G, none among the infants and parents were found to carry the AA genotype. No statistically significant differences were found between children, mothers and fathers belonging to preterm and at-term groups. We did not find a statistically significant association in newborns and their mother, but our results show a statistical correlation with the LEPRA668G genotype GG of the father. This fact can contribute to defining genetic risk factors for PTB. Further studies are certainly needed to better clarify the role of genetics in influencing preterm delivery.

Enhancing Oral Delivery of Biologics: A Non-Competitive and Cross-Reactive Anti-Leptin Receptor Nanofitin Demonstrates a Gut-Crossing Capacity in an Ex Vivo Porcine Intestinal Model.

Biotherapeutics exhibit high efficacy in targeted therapy, but their oral delivery is impeded by the harsh conditions of the gastrointestinal (GI) tract and limited intestinal absorption. This article presents a strategy to overcome the challenges of poor intestinal permeability by using a protein shuttle that specifically binds to an intestinal target, the leptin receptor (LepR), and exploiting its capacity to perform a receptor-mediated transport. Our proof-of-concept study focuses on the characterization and transport of robust affinity proteins, known as Nanofitins, across an ex vivo porcine intestinal model. We describe the potential to deliver biologically active molecules across the mucosa by fusing them with the Nanofitin 1-F08 targeting the LepR. This particular Nanofitin was selected for its absence of competition with leptin, its cross-reactivity with LepR from human, mouse, and pig hosts, and its shuttle capability associated with its ability to induce a receptor-mediated transport. This study paves the way for future in vivo demonstration of a safe and efficient oral-to-systemic delivery of targeted therapies.

Полиморфные варианты генов LEP и LEPR у пациентов с инфарктом миокарда: связь с уровнем лептина и его растворимым рецептором в сыворотке крови

Aim: to determine the association between the rs7799039, rs1137100, and rs1137101 polymorphic variants of the LEPR gene and serum leptin and its soluble receptor levels in patients with myocardial infarction (MI) and obesity. Patients and Methods: the study included 146 patients (108 men and 38 women) with an established MI, with a mean age of 57 (51; 64) years. The control group consisted of 300 conditionally healthy individuals (110 men and 190 women). The levels of leptin and its soluble receptor were measured by solid phase enzyme immunoassay Genetic analysis was performed using genomic DNA isolated from whole blood Polymorphic variants (rs7799039, rs1137100, rs1137101) of LEP and LEPR genes were genotyped by PCR with fluorescein-labeled probes Results: carrying the G allele of the polymorphic variant rs1137100 of the LEPR gene increases the risk of MI by 7 times in the recessive inheritance (odds ratio/OR=7.62, 95% confidence interval/CI 4.14-14.02). The rs1137101 variant of the LEPR gene has a protective effect in terms of the risk of MI. Furthermore, there were no significant differences in genotype rate between the groups of patients without obesity and with obesity The study found that individuals with the A/G and G/G genotypes of the rs1137100 variant of the LEPR gene had significantly higher levels of soluble leptin receptor (39.57 (30.59; 54.53) ng/mL) compared to those with the A/A genotype (24.29 (19.49; 34.70) ng/mL). Conclusion: the G allele of the LEPR gene is associated with an increased risk of MI and higher serum levels of soluble leptin receptor. These phenomena may be associated with a more unfavorable course of the cardio-metabolic continuum in these patients, particularly in those who are obese. KEYWORDS: myocardial infarction, leptin, polymorphic variant, leptin receptor, LEP, LEPR FOR CITATION: Hryachkova O.N., Khutornaya M.V., Sinitskaya A.V., Sinitskiy M.Yu., Kashtalap V.V. Polymorphic variants of LEP and LEPR genes in patients with myocardial infarction: association with serum leptin and its soluble receptor levels. Russian Medical Inquiry. 2024;8(1):4–8 (in Russ.). DOI: 10.32364/2587-6821-2024-8-1-1.

CORRELATION OF LEPTIN AND ADIPONECTIN RECEPTOR EXPRESSION WITH CLINICOPATHOLOGICAL PARAMETERS IN COLORECTAL CARCINOMA - A CROSS-SECTIONAL PROSPECTIVE STUDY.

Colorectal carcinoma (CRC) is one of the common carcinomas with a rising incidence of metastasis due to its advanced stage of presentation. The existing biomarkers such as CEA (Carcinoembryonic antigen) etc., for prognosis, have low sensitivity and specificity. Hence a need for a newer definitive biomarker. Obesity is the leading cause of CRC. Leptin and adiponectin secreted by adipose tissue have been studied as potential biomarkers in the field of CRC. The present study helps to understand the association of leptin and adiponectin receptors with clinicopathological parameters. To correlate the various clinicopathological parameters with the tissue expression of leptin and adiponectin receptors in CRC. It is a cross-sectional prospective study conducted at a tertiary care hospital. Formalin fixed paraffin blocks of all radical resection CRC cases were collected and immunohistochemistry (IHC)was carried out on tumor tissue for leptin and adiponectin receptor. Tumor characteristics and clinical parameters were collected from the hospital medical records. Pearson's correlation coefficient test was used. Immunohistochemistry was performed on 60 cases of CRC. Significant positive correlation of leptin was observed with size, lymph node metastasis, advanced stage, and grade of tumor (P<0.05). A significant correlation between adiponectin receptor and CRC was observed concerning age, stage, lymph node metastasis, distant metastasis and grade of tumor. Positive expression of leptin and negative expression of adiponectin receptors in CRC helps to predict the risk of metastasis.

The Mechanism of Leptin Resistance in Obesity and Therapeutic Perspective.

Leptin resistance is induced via leptin signaling blockade by chronic overstimulation of the leptin receptor and intracellular signaling defect or increased hypothalamic inflammation and suppressor of cytokine signaling (SOCS)-3 expression. High-fat diet triggers leptin resistance induced by at least two independent causes: first, the limited ability of peripheral leptin to activate hypothalamic signaling transducers and activators of transcription (STAT) signaling and secondly a signaling defect in leptin-responsive hypothalamic neurons. Central leptin resistance is dependent on decreased leptin transport efficiency across the blood brain barrier (BBB) rather than hypothalamic leptin insensitivity. Since the hypothalamic phosphorylated STAT3 (pSTAT3) represents a sensitive and specific readout of leptin receptor-B signaling, the assessment of pSTAT3 levels is the gold standard. Hypertriglyceridemia is one of important factors to inhibit the transport of leptin across BBB in obesity. Mismatch between high leptin and the amount of leptin receptor expression in obesity triggers brain leptin resistance via increasing hypothalamic inflammation and SOCS-3 expression. Therapeutic strategies that regulate the passage of leptin to the brain include the development of modifications in the structure of leptin analogues as well as the synthesis of new leptin receptor agonists with increased BBB permeability. In the hyperleptinemic state, polyethylene glycol (PEG)-modified leptin is unable to pass through the BBB. Peripheral histone deacetylase (HDAC) 6 inhibitor, tubastatin, and metformin increase central leptin sensitization. While add-on therapy with anagliptin, metformin and miglitol reduce leptin concentrations, the use of long-acting leptin analogs, and exendin-4 lead to the recovery of leptin sensitivity. Contouring surgery with fat removal, and bariatric surgery independently of the type of surgery performed provide significant improvement in leptin concentrations. Although approaches to correcting leptin resistance have shown some success, no clinically effective application has been developed to date. Due to the impairment of central and peripheral leptin signaling, as well as the extensive integration of leptin-sensitive metabolic pathways with other neurons, the effectiveness of methods used to eliminate leptin resistance is extremely limited.

In-silico detection of deleterious mutation in LEPR gene in dairy cattle

In-silico detection of deleterious mutation in LEPR gene in dairy cattle