Tissue-Specific Effects of Leptin on Glucose and Lipid Metabolism

Hesperetin mitigates adipose tissue inflammation to improve obesity-associated metabolic health

Metabolically unhealthy obesity (MUO) poses significant health risks, including increased susceptibility to type 2 diabetes and cardiovascular diseases. Hesperetin is a key bioactive compound found in citrus fruits. Previous studies have shown that hesperetin can correct metabolic abnormalities and mitigate the progression of various metabolic disorders, but the underlying mechanisms remain unclear. Here, we explored the impact of hesperetin on MUO using ob/ob mice and investigated its potential pharmacological mechanisms. The present data indicated that administration of hesperetin for 12 weeks led to notable improvements in metabolic parameters, including reduced fasting blood glucose, fasting insulin levels, and the HOMA-IR index in ob/ob mice. Glucose and insulin tolerance tests demonstrated that hesperetin effectively enhanced insulin sensitivity, with high-dose effects comparable to metformin. Hesperetin treatment decreased inguinal white adipose tissue (iWAT) weight and improved insulin signaling by increasing AKT phosphorylation. Additionally, it reduced the expression of pro-inflammatory cytokines (Il-6 and Il-1β), chemokine Ccl2 and its receptor Ccr2, and macrophage activation markers Nos2 and Ptgs2 within iWAT of ob/ob mice, likely by inhibiting NF-κB activation and macrophage-mediated inflammation. In vitro studies further confirmed hesperetin's anti-inflammatory effects in LPS-stimulated macrophages, where it suppressed cytokine production and NF-κB signaling. Hesperetin also impaired CCL2-induced macrophage chemotaxis, reducing migration velocity and distance. Mechanistically, hesperetin directly interacts with and inhibits IKKβ kinase activity by binding to key residues (LEU21, VAL465, CYS99, and GLU97) and stabilizing the complex, as demonstrated by molecular docking and molecular dynamics simulations. These findings underscore hesperetin's therapeutic potential in mitigating metabolically unhealthy obesity, obesity-induced insulin resistance, and inflammation through direct modulation of the IKKβ and NF-κB pathways.

Leptin signaling promotes milk fat synthesis via PI3K/AKT/mTOR/SREBP1 in mammary gland of dairy cow

Milk fat synthesis is tightly regulated by hormones and growth factors. Leptin is a versatile peptide hormone that exerts pleiotropic effects on metabolic pathways. In this study, we evaluated the expression and function of leptin and its long form receptor OB-Rb in dairy cow mammary tissues from different physiological stages and in cultured mammary epithelial cells. The results showed that the expression of leptin and OB-Rb were significantly higher in the mammary tissues of lactating cows as compared with dry cows, suggesting that they are related to milk component synthesis. In cultured dairy cow mammary epithelial cells, leptin treatment significantly increased OB-Rb expression and intracellular triacylglycerol content. Transcriptome analysis identified the difference in gene expression between leptin treated cells and control cells, and 317 differentially expressed genes were identified. Gene ontology and pathway mapping showed that lipid metabolism-related gene expression increased and signal transduction pathway-related genes were the most significantly enriched. Mechanistic studies showed that leptin stimulation enhanced sterol regulatory element-binding protein 1 expression via activating the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway, which in turn up-regulated the expression of genes related to milk fat synthesis. Moreover, we found that fatty acid synthesis precursors, acetate and β-hydroxybutyrate, could positively regulate the expression of leptin and OB-Rb in bovine mammary epithelial cells, thereby potentially increasing milk fat synthesis. Our study provided novel evidence in the regulation of leptin on milk fat production in mammary glands of dairy cows, as well as experimental basis for artificial regulation of milk fat.

The circadian rhythm: A new target of natural products that can protect against diseases of the metabolic system, cardiovascular system, and nervous system

BACKGROUND

The treatment of metabolic system, cardiovascular system, and nervous system diseases remains to be explored. In the internal environment of organisms, the metabolism of substances such as carbohydrates, lipids and proteins (including biohormones and enzymes) exhibit a certain circadian rhythm to maintain the energy supply and material cycle needed for the normal activities of organisms. As a key factor for the health of organisms, the circadian rhythm can be disrupted by pathological conditions, and this disruption accelerates the progression of diseases and results in a vicious cycle. The current treatments targeting the circadian rhythm for the treatment of metabolic system, cardiovascular system, and nervous system diseases have certain limitations, and the identification of safer and more effective circadian rhythm regulators is needed.

AIM OF THE REVIEW

To systematically assess the possibility of using the biological clock as a natural product target for disease intervention, this work reviews a range of evidence on the potential effectiveness of natural products targeting the circadian rhythm to protect against diseases of the metabolic system, cardiovascular system, and nervous system. This manuscript focuses on how natural products restore normal function by affecting the amplitude of the expression of circadian factors, sleep/wake cycles and the structure of the gut microbiota.

KEY SCIENTIFIC CONCEPTS OF THE REVIEW

This work proposes that the circadian rhythm, which is regulated by the amplitude of the expression of circadian rhythm-related factors and the sleep/wake cycle, is crucial for diseases of the metabolic system, cardiovascular system and nervous system and is a new target for slowing the progression of diseases through the use of natural products. This manuscript provides a reference for the molecular modeling of natural products that target the circadian rhythm and provides a new perspective for the time-targeted action of drugs.

Unraveling the Health Benefits and Mechanisms of Time-Restricted Feeding: Beyond Caloric Restriction

Time-restricted feeding (TRF) is a lifestyle intervention that aims to maintain a consistent daily cycle of feeding and fasting to support robust circadian rhythms. Recently, it has gained scientific, medical, and public attention due to its potential to enhance body composition, extend lifespan, and improve overall health, as well as induce autophagy and alleviate symptoms of diseases like cardiovascular diseases, type 2 diabetes, neurodegenerative diseases, cancer, and ischemic injury. However, there is still considerable debate on the primary factors that contribute to the health benefits of TRF. Despite not imposing strict limitations on calorie intake, TRF consistently led to reductions in calorie intake. Therefore, while some studies suggest that the health benefits of TRF are primarily due to caloric restriction (CR), others argue that the key advantages of TRF arise not only from CR but also from factors like the duration of fasting, the timing of the feeding period, and alignment with circadian rhythms. To elucidate the roles and mechanisms of TRF beyond CR, this review incorporates TRF studies that did not use CR, as well as TRF studies with equivalent energy intake to CR, which addresses the previous lack of comprehensive research on TRF without CR and provides a framework for future research directions.

Leptin enhances the intracellular thyroid hormone activation in skeletal muscle to boost energy balance

Thyroid hormones (THs) are key modulators of energy metabolism and cross-talk with other endocrine and metabolic factors. Notably, leptin can increase hypothalamic control of TH synthesis as an adaptive metabolic response regulating body weight. In this study, we found that the TH signal is heightened in overweight humans and is lost with obesity. In mice, systemic and intracerebroventricular leptin injection induces the expression of type 2 deiodinase (D2), the TH-activating enzyme, in skeletal muscle. Mechanistically, leptin enhances the transcription of D2 by a STAT3- and α-melanocyte-stimulating hormone (α-MSH)/cyclic AMP (cAMP)-dependent regulation. Notably, mice lacking D2 or with a mutation in the TH receptor do not exhibit the metabolic effects of leptin, such as increased insulin sensitivity and oxygen consumption, indicating that leptin's peripheral metabolic effects in skeletal muscle are mediated by TH. These findings underscore the critical role of leptin in integrating the TH-induced metabolic activation, while also contributing to appetite suppression in response to perceived fat stores.

Natural Products From Plants Targeting Leptin Resistance for the Future Development of Anti-Obesity Agents

Obesity is a serious health threat, which has affected 16% of adults globally in 2022 and shows a trend toward youthfulness. Leptin, as a regulator of body weight, can suppress appetite and promote energy expenditure, making it potential in obesity treatment. Nevertheless, with the progress of relevant research, it is worth noting that monotherapy with leptin is not an effective strategy since most obese individuals are hyperleptinemic and resistant to leptin, where high levels of leptin fail to exert its weight-loss effects. Therefore, the potential to unlock the weight-loss properties of leptin using pharmacology to improve resistance has provided a new direction for this field. However, most synthetic medicines have retreated from the market due to their undesirable side effects, while natural products are increasingly sought after for drug development due to their minimal side effects. Indeed, natural products are ideal alternatives to oral synthetic agents since a growing body of research has demonstrated their desirable effects on improving leptin resistance through potential therapeutic targets like the JAK2/STAT3 signaling pathway, protein tyrosine phosphatase 1B, the exchange proteins directly activated by cAMP/Ras-related protein 1 signaling pathway, endoplasmic reticulum stress, pro-opiomelanocortin gene, and leptin levels. This review outlines natural products that can improve leptin resistance by inhibiting or activating these targets and evaluates their efficacy in experiments and human clinical trials, offering insights for the development of anti-obesity agents. However, more high-quality clinical research is necessary to validate these findings, as current clinical evidence is constrained by heterogeneity and small sample sizes.

Effect of life course body composition on lipids and coronary atherosclerosis mediated by inflammatory biomarkers

OBJECTIVE

To investigate the mediating role of inflammatory biomarkers in the causal effect of body composition on lipids and atherosclerosis.

METHODS

Retrospective observational study and Mendelian randomization (MR) study were used. Observational analyses were undertaken using data from 4717 children and adolescents aged 6-18 years from Chinese who underwent dual-energy x-ray absorptiometry for body composition. MR analyses were based on summary statistics from UK Biobank, deCODE2021, GLGC, FinnGen and other large consortiums. Inflammatory biomarkers included leptin, insulin, adiponectin, osteocalcin, fibroblast growth factor 23 (FGF23) and parathyroid hormone (PTH).

RESULTS

In retrospective observational study, through osteocalcin, body composition had effects on total cholesterol (TC), triglyceride and low-density lipoprotein cholesterol (LDL). Conversely, fat mass vs. fat-free mass demonstrated opposing effects. Insulin played a role in the association of fat mass with TC and LDL (all P < 0.05). Mediation MR results indicated the causal effect of fat-free mass on coronary atherosclerosis via insulin (indirect effect, OR (odds ratio): 0.95 [95%CI, 0.92-0.98]) and adiponectin (OR: 0.96 [95%CI, 0.93-0.99]). Adiponectin also mediated the causal association of fat mass with coronary heart disease (OR: 1.06 [95%CI, 1.02-1.10]) and coronary atherosclerosis (OR: 1.05 [95%CI, 1.01, 1.09]). Leptin, adiponectin and insulin played roles in mediating the casual effects of body composition on triglyceride and high-density lipoprotein cholesterol.

CONCLUSIONS

Our findings suggest different body composition exert varying influences on lipids and atherosclerosis through distinct inflammatory biomarkers. The findings may be helpful in tailoring management of body composition based on inflammatory biomarkers with different lipid profiles.

Impact of protein intake from a caloric-restricted diet on liver lipid metabolism in overweight and obese rats of different sexes

In addition to being linked to an excess of lipid accumulation in the liver, being overweight or obese can also result in disorders of lipid metabolism. There is limited understanding regarding whether different levels of protein intake within an energy-restricted diet affect liver lipid metabolism in overweight and obese rats and whether these effects differ by gender, despite the fact that both high protein intake and calorie restriction can improve intrahepatic lipid. The purpose of this study is to explore the effects and mechanisms of different protein intakes within a calorie-restricted diet on liver lipid metabolism, and to investigate whether these effects exhibit gender differences. The Sprague-Dawley rats, which were half female and half male, were used to construct a rat model of overweight and obesity attributed to a high-fat diet. They were then split up into five groups: the normal control (NC) group, the model control (MC) group, the calorie-restricted low protein (LP) group, the calorie-restricted normal protein (NP) group, and the calorie-restricted high protein (HP) group. Body weight was measured weekly. Samples of plasma and liver were obtained after eight weeks and analyzed for glucose, triglycerides, cholesterol, and hormones in the plasma as well as the liver fat and factors involved in the liver's synthesis and degradation. For the male rats, compared to the HP group, the weight of liver fat in the LP and NP group was significantly higher (P < 0.05). However, for the female rats, there was no significant variation among the three calorie-restricted groups (P > 0.05). There was no significant variation in the concentration of total cholesterol (TC), very low density lipoprotein (VLDL), low density lipoprotein (LDL), and high density lipoprotein (HDL) among the three male calorie-restricted groups (P > 0.05), while the TC and VLDL concentrations in the female LP and NP group were significantly higher compared to those in the HP group (P < 0.05). Moreover, the trend of expression in the signaling pathways of adiponectin/phosphorylated AMP-activated protein kinase (p-AMPK) and adiponectin/peroxisome proliferators-activated receptor alpha (PPARα) in the liver was consistent with that of the liver fat content, and leptin acted in the same way as adiponectin. Compared with the three calorie-restricted groups, the expressions of nuclear sterol-regulatory element-binding protein-2 (nSREBP-2) and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) involved in cholesterol synthesis and low-density lipoprotein receptor (LDLR) and cholesterol 7-alpha hydroxylase (CYP7A1) involved in cholesterol clearance in the MC group were significantly lower (P < 0.05). A 40% energy restriction can significantly reduce the body weight, body fat, liver fat, and the blood concentration of TG in both male and female overweight and obese rats, but it can significantly increase the blood concentration of TC in overweight and obese male rats. At the same time of 40% calorie restriction, increasing dietary protein intake to twice the normal protein intake has a stronger effect on promoting hepatic triglyceride oxidation and reducing liver fat content in the male overweight and obese rats by increasing the levels of adiponectin and leptin in the blood, and can also significantly reduce the plasma cholesterol concentration in the female overweight and obese rats through inhibiting cholesterol synthesis most likely by increasing glucagon level in the blood.

Iron-Mediated Regulation in Adipose Tissue: A Comprehensive Review of Metabolism and Physiological Effects

PURPOSE OF REVIEW

Review the latest data regarding the intersection of adipose tissue (AT) and iron to meet the needs of AT metabolism and the progression of related diseases.

RECENT FINDINGS

Iron is involved in fundamental biological metabolic processes and is precisely fine-tuned within the body to maintain cellular, tissue and even systemic iron homeostasis. AT not only serves as an energy storage depot but also represents the largest endocrine organ in the human body, maintaining systemic metabolic homeostasis. It is involved in physiological processes such as energy storage, insulin sensitivity regulation and lipid metabolism. As a unique iron-sensing tissue, AT expresses related regulatory factors, including the classic hepcidin, ferroportin (FPN), iron regulatory protein/iron responsive element (IRP/IRE) and ferritin. Consequently, the interaction between AT and iron is intricately intertwined. Imbalance of iron homeostasis produces the potential risks of steatosis, impaired glucose tolerance and insulin resistance, leading to AT dysfunction diseases, including obesity, type 2 diabetes and metabolic dysfunction-associated steatotic liver disease (MASLD). Despite the role of AT iron has garnered increasing attention in recent years, a comprehensive review that systematically organizes the connection between iron and AT remains lacking. Given the necessity of iron homeostasis, emphasizing its potential impact on AT function and metabolism regulation provides valuable insights into physiological effects such as adipocyte differentiation and thermogenesis. Futhermore, regulators including adipokines, mitochondria and macrophages have been mentioned, along with analyzing the novel perspective of iron as a key mediator influencing the fat-gut crosstalk.

The relevance of the heme oxygenase system in alleviating diabetes-related hormonal and metabolic disorders

Heme oxygenase (HO) is an enzyme that catalyzes heme degradation. HO dysfunction is linked to various pathological conditions, including diabetes. Results of animal studies indicate that HO expression and activity are downregulated in experimentally induced diabetes. This is associated with severe hormonal and metabolic disturbances. However, these pathological changes have been shown to be reversed by therapy with HO activators. In animals with experimentally induced diabetes, HO was upregulated by genetic manipulation or by pharmacological activators such as hemin and cobalt protoporphyrin. Induction of HO alleviated elevated blood glucose levels and improved insulin action, among other effects. This effect resulted from beneficial changes in the main insulin-sensitive tissues, i.e., the skeletal muscle, the liver, and the adipose tissue. The action of HO activators was due to positive alterations in pivotal signaling molecules and regulatory enzymes. Furthermore, diabetes-related oxidative and inflammatory stress was reduced due to HO induction. HO upregulation was effective in various animal models of type 1 and type 2 diabetes. These data suggest the possibility of testing HO activators as a potential tool for alleviating hormonal and metabolic disorders in people with diabetes.

Regulation of energy balance by leptin as an adiposity signal and modulator of the reward system

BACKGROUND

Leptin is an adipose tissue-derived hormone that plays a crucial role in body weight, appetite, and behaviour regulation. Leptin controls energy balance as an indicator of adiposity levels and as a modulator of the reward system, which is associated with liking palatable foods. Obesity is characterized by expanded adipose tissue mass and consequently, elevated concentrations of leptin in blood. Leptin's therapeutic potential for most forms of obesity is hampered by leptin resistance and a narrow dose-response window.

SCOPE OF REVIEW

This review describes the current knowledge of the brain regions and intracellular pathways through which leptin promotes negative energy balance and restrains neural circuits affecting food reward. We also describe mechanisms that hinder these biological responses in obesity and highlight potential therapeutic interventions.

MAJOR CONCLUSIONS

Additional research is necessary to understand how pathways engaged by leptin in different brain regions are interconnected in the control of energy balance.

Insulin and leptin acutely modulate the energy metabolism of primary hypothalamic and cortical astrocytes

Astrocytes constitute a heterogeneous cell population within the brain, contributing crucially to brain homeostasis and playing an important role in overall brain function. Their function and metabolism are not only regulated by local signals, for example, from nearby neurons, but also by long-range signals such as hormones. Thus, two prominent hormones primarily known for regulating the energy balance of the whole organism, insulin, and leptin, have been reported to also impact astrocytes within the brain. In this study, we investigated the acute regulation of astrocytic metabolism by these hormones in cultured astrocytes prepared from the mouse cortex and hypothalamus, a pivotal region in the context of nutritional regulation. Utilizing genetically encoded, fluorescent nanosensors, the cytosolic concentrations of glucose, lactate, and ATP, along with glycolytic rate and the NADH/NAD+ redox state were measured. Under basal conditions, differences between the two populations of astrocytes were observed for glucose and lactate concentrations as well as the glycolytic rate. Additionally, astrocytic metabolism responded to insulin and leptin in both brain regions, with some unique characteristics for each cell population. Finally, both hormones influenced how cells responded to elevated extracellular levels of potassium ions, a common indicator of neuronal activity. In summary, our study provides evidence that insulin and leptin acutely regulate astrocytic metabolism within minutes. Additionally, while astrocytes from the hypothalamus and cortex share similarities in their metabolism, they also exhibit distinct properties, further underscoring the growing recognition of astrocyte heterogeneity.

Leptin increases chemosensitivity by inhibiting CPT1B in colorectal cancer cells

Background

Chemoresistance is a major cause of treatment failure in advanced colorectal cancer (CRC), severely impacting patient survival and quality of life. While conventional chemotherapy regimens can somewhat control tumor progression, their effectiveness is frequently compromised by the development of drug resistance in cancer cells. The aim of this study is to verify and elucidate the specific mechanisms by which leptin enhances chemosensitivity in CRC, providing valuable insights for the development of new combination chemotherapy options.

Methods

We examined the link between CRC chemoresistance and fatty-acid metabolism driven by the high expression of carnitine palmitoyltransferase-1b (CPT1B) through an integrated approach combining bioinformatics and clinical sample analysis. In vitro and in vivo experiments were conducted to evaluate the effect of leptin, an adipocyte-derived cytokine, on CRC cells' response to cisplatin.

Results

Leptin significantly enhanced CRC cells' chemosensitivity to cisplatin by downregulating CPT1B expression, thereby disrupting the fatty-acid oxidation pathways that support drug resistance. In mouse models, the coadministration of leptin and cisplatin resulted in notable reductions in tumor size and weight compared to cisplatin alone, underscoring leptin's potential to enhance chemotherapy efficacy.

Conclusions

These findings indicate that leptin, through modulation of CPT1B, may serve as a promising adjunct to chemotherapy for CRC, addressing the challenge of chemoresistance and improving therapeutic outcomes. The leptin-CPT1B axis may be potential therapeutic target, providing new avenues for CRC treatment strategies aimed at overcoming drug resistance.

Spotlight on the Mechanism of Action of Semaglutide

Initially intended to control blood glucose levels in patients with type 2 diabetes, semaglutide, a potent glucagon-like peptide 1 analogue, has been established as an effective weight loss treatment by controlling appetite. Integrating the latest clinical trials, semaglutide in patients with or without diabetes presents significant therapeutic efficacy in ameliorating cardiometabolic risk factors and physical functioning, independent of body weight reduction. Semaglutide may modulate adipose tissue browning, which enhances human metabolism and exhibits possible benefits in skeletal muscle degeneration, accelerated by obesity and ageing. This may be attributed to anti-inflammatory, mitochondrial biogenesis, antioxidant and autophagy-regulating effects. However, most of the supporting evidence on the mechanistic actions of semaglutide is preclinical, demonstrated in rodents and not actually confirmed in humans, therefore warranting caution in the interpretation. This article aims to explore potential innovative molecular mechanisms of semaglutide action in restoring the balance of several interlinking aspects of metabolism, pointing to distinct functions in inflammation and oxidative stress in insulin-sensitive musculoskeletal and adipose tissues. Moreover, possible applications in protection from infections and anti-aging properties are discussed. Semaglutide enhancement of the core molecular mechanisms involved in the progress of obesity and diabetes, although mostly preclinical, may provide a framework for future research applications in human diseases overall.

Ramulus Mori (Sangzhi) alkaloids ameliorate high-fat diet induced obesity in rats by modulating gut microbiota and bile acid metabolism

Objective

The objective of this study is to investigate the ability of Ramulus Mori (Sangzhi) alkaloid tablets (SZ-A) to ameliorate obesity and lipid metabolism disorders in rats subjected to a high-fat diet (HFD) through metagenomics, untargeted lipidomics, targeted metabolism of bile acid (BA), and BA pathways, providing a novel perspective on the management of metabolic disorders.

Methods

In this research, HFD-fed rats were concurrently administered SZ-A orally. We measured changes in body weight (BW), blood lipid profiles, and liver function to assess therapeutic effects. Liver lipid status was visualized through H&E and Oil Red O. Gut microbiota composition was elucidated using metagenomics. The LC-MS-targeted metabolomics approach was utilized to define the fecal BA profiles. Furthermore, the lipid metabolomics of adipose tissue samples was investigated using an LC-MS analysis platform. The expression levels of the BA receptor were determined by western blotting. Additionally, serum insulin (INS), glucagon-like peptide-1 (GLP-1), and inflammatory cytokines were quantified using an ELISA kit. The integrity of the colonic epithelial barrier was assessed using immunofluorescence.

Results

SZ-A notably decreased BW and blood lipid levels in obese rats while also alleviating liver injury. Additionally, SZ-A reduced the serum levels of leptin (LEP), INS, and GLP-1, indicating its potential to modulate key metabolic hormones. Most notably, SZ-A substantially improved gut microbiota composition. Specifically, it reshaped the gut microbiota structure in HFD-fed rats by increasing the relative abundance of beneficial bacteria, such as Bacteroides, while decreasing the populations of potentially harmful bacteria, such as Dorea and Blautia. At the BA level, SZ-A decreased the levels of harmful BAs, including hyodeoxycholic acid (HDCA), deoxycholic acid (DCA), 12-keto lithocholic acid (12-KLCA), lithocholic acid (LCA), and muricholic acid (MDCA). Between the model group and SZ-A, 258 differentially abundant metabolites were detected, with 72 upregulated and 186 downregulated. Furthermore, these BAs are implicated in the activation of the FXR-FGF15 and TGR5-GLP-1 pathways in the intestine. This activation helps to alleviate HFD-fed intestinal inflammation and restore intestinal barrier damage by modulating inflammatory cytokines and bolstering the intestinal barrier's capabilities.

Conclusions

Our findings indicate that SZ-A effectively modulates BW, serum lipid profiles, and liver function in HFD-fed rats. Moreover, SZ-A exerts a positive influence on inflammatory cytokines, thereby mitigating inflammation and promoting the restoration of the intestinal barrier. Significantly, our research indicates that adjusting the gut microbiome and BA levels could serve as an effective approach for both preventing and treating obesity and related metabolic dyslipidemia.

Metabolic disorders, inter-organ crosstalk, and inflammation in the progression of metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a global health concern, affecting over 30 % of adults. It is a principal driver in the development of cirrhosis and hepatocellular carcinoma. The complex pathogenesis of MASLD involves an excessive accumulation of lipids, subsequently disrupting lipid metabolism and prompting inflammation within the liver. This review synthesizes the recent research progress in understanding the mechanisms contributing to MASLD progression, with particular emphasis on metabolic disorders and interorgan crosstalk. We highlight the molecular mechanisms linked to these factors and explore their potential as novel targets for pharmacological intervention. The insights gleaned from this article have important implications for both the prevention and therapeutic management of MASLD.

Lactobacillus delbrueckii subsp. lactis CKDB001 Ameliorates Metabolic Complications in High-Fat Diet-Induced Obese Mice

BACKGROUND/OBJECTIVES

Functional probiotics, particularly Lactobacillus delbrueckii subsp. lactis CKDB001, have shown potential as a therapeutic option for metabolic dysfunction-associated steatotic liver disease (MASLD). However, their effects have not been confirmed in in vivo systems. Here, we investigated the effects of L. delbrueckii subsp. lactis CKDB001 on insulin resistance, dyslipidemia, MASLD, and lipid metabolism in a murine model of high-fat diet (HFD)-induced obesity.

METHODS

The mice were divided into four groups (n = 12 per group)-normal chow diet (NCD), high fat diet (HFD), HFD with L. delbrueckii subsp. lactis CKDB001 (LL), and HFD with resmetirom (positive control (PC), a thyroid receptor β agonist). The experimental animals were fed NCD or HFD for 12 weeks, followed by an additional 12-week oral treatment with LL or resmetirom.

RESULTS

LL supplementation reduced body weight, insulin levels, and HOMA-IR compared with those in the HFD group, indicating improved insulin sensitivity. Additionally, LL reduced serum triglyceride (TG) levels without affecting total cholesterol (TC) levels. HFD consumption increased liver weight and hepatic TG and TC levels, indicating ectopic fat accumulation; however, LL supplementation reversed these changes, indicating a liver-specific effect on cholesterol metabolism. Furthermore, LL administration attenuated NAFLD activity scores, reduced hepatic fibrosis, improved liver function markers (aspartate aminotransferase), and enhanced Adenosine monophosphate-activated protein kinase (AMPK) phosphorylation. However, LL did not considerably affect the expression of genes related to lipid metabolism. In epididymal adipose tissue, LL treatment reduced leptin levels but had no effect on adiponectin; additionally, histological analysis showed an increase in adipocyte size, potentially linked to enhanced energy metabolism.

CONCLUSIONS

Collectively, these findings suggest that LL could be a promising therapeutic candidate for improving insulin sensitivity, reducing hepatic lipid accumulation, and mitigating MASLD.

TRPV1: A novel target for the therapy of diabetes and diabetic complications

BACKGROUND

Diabetes mellitus is a chronic metabolic disease characterized by abnormally elevated blood glucose levels. Type II diabetes accounts for approximately 90% of all cases. Several drugs are available for hyperglycemia treatment. However, the current therapies for managing high blood glucose do not prevent or reverse the disease progression, which may result in complications and adverse effects, including diabetic neuropathy, retinopathy, and nephropathy. Hence, developing safer and more effective methods for lowering blood glucose levels is imperative. Transient receptor potential vanilloid-1 (TRPV1) is a significant member of the transient receptor potential family. It is present in numerous body tissues and organs and performs vital physiological functions.

PURPOSE

This review aimed to develop new targeted TRPV1 hypoglycemic drugs by systematically summarizing the mechanism of action of the TRPV1-based signaling pathway in preventing and treating diabetes and its complications.

METHODS

Literature searches were performed in the PubMed, Web of Science, Google Scholar, Medline, and Scopus databases for 10 years from 2013 to 2023. The search terms included "diabetes," "TRPV1," "diabetic complications," and "capsaicin."

RESULTS

TRPV1 is an essential potential target for treating diabetes mellitus and its complications. It reduces hepatic glucose production and food intake and promotes thermogenesis, metabolism, and insulin secretion. Activation of TRPV1 ameliorates diabetic nephropathy, retinopathy, myocardial infarction, vascular endothelial dysfunction, gastroparesis, and bladder dysfunction. Suppression of TRPV1 improves diabetes-related osteoporosis. However, the therapeutic effects of activating or suppressing TRPV1 may vary when treating diabetic neuropathy and periodontitis.

CONCLUSION

This review demonstrates that TRPV1 is a potential therapeutic target for diabetes and its complications. Additionally, it provides a theoretical basis for developing new hypoglycemic drugs that target TRPV1.

Features of Metabolism and Its Regulation in the Dynamics of Experimental Models of Metabolic Disorders

Changes in the lipid and carbohydrate metabolism, adipokines, and growth factors during the development of metabolic disorders were studied in three mouse models: C57BL/6 (alimentary obesity), db/db (leptin-resistant obesity), and NOD (diabetes mellitus) lines. In the group of alimentary obesity, moderate fatty infiltration of the liver and hypertrophy of the adipose tissue, hyperglycemia, and increased concentrations of adiponectin, transforming growth factor β1 (TGF-β1), leptin, and cholesterol were detected. In the group of leptin-resistant obesity, multiple pathological changes in tissues, severe hyperglycemia and hyperleptinemia, hyperinsulinemia, and reduced concentrations of triglycerides, adiponectin, myostatin, and TGF-β1 were detected. In NOD mice, reduced number of insulin-positive β cells, hyperinsulinemia, and a decrease in adiponectin, TGF-β1, leptin, and myostatin concentrations were detected.

A gut microbial metabolite cocktail fights against obesity through modulating the gut microbiota and hepatic leptin signaling

BACKGROUND

Excessive body weight and obesity elevate the risk of chronic non-communicable diseases. The judicious application of the gut microbiome, encompassing both microorganisms and their derived compounds, holds considerable promise in the treatment of obesity.

RESULTS

In this study, we showed that a cocktail of gut microbiota-derived metabolites, comprising indole 3-propionic acid (IPA), sodium butyrate (SB) and valeric acid (VA), alleviated various symptoms of obesity in both male and female mice subjected to a high-fat diet (HFD). The 16S ribosomal RNA (rRNA) sequencing revealed that administering the cocktail via oral gavage retained the gut microbiota composition in obese mice. Fecal microbiota transplantation using cocktail-treated mice as donors mitigated the obesity phenotype of HFD-fed mice. Transcriptomic sequencing analysis showed that the cocktail preserved the gene expression profile of hepatic tissues in obese mice, especially up-regulated the expression level of leptin receptor. Gene delivery via in vivo fluid dynamics further validated that the anti-obesity efficacy of the cocktail was dependent on leptin signaling at least partly. The cocktail also inhibited the expression of appetite stimulators in hypothalamus. Together, the metabolite cocktail combated adiposity by retaining the gut microbiota configuration and activating the hepatic leptin signaling pathway.

CONCLUSIONS

Our findings provide a sophisticated regulatory network between the gut microbiome and host, and highlight a cocktail of gut microbiota-derived metabolites, including IPA, SB, and VA, might be a prospective intervention for anti-obesity in a preclinical setting. © 2024 Society of Chemical Industry.

The causal impact of gut microbiota on circulating adipokine concentrations: a two-sample Mendelian randomization study

PURPOSE

Evidence from previous experimental and observational research demonstrates that the gut microbiota is related to circulating adipokine concentrations. Nevertheless, the debate as to whether gut microbiome composition causally influences circulating adipokine concentrations remains unresolved. This study aimed to take an essential step in elucidating this issue.

METHODS

We used two-sample Mendelian randomization (MR) to causally analyze genetic variation statistics for gut microbiota and four adipokines (including adiponectin, leptin, soluble leptin receptor [sOB-R], and plasminogen activator inhibitor-1 [PAI-1]) from large-scale genome-wide association studies (GWAS) datasets. A range of sensitivity analyses was also conducted to assess the stability and reliability of the results.

RESULTS

The composite results of the MR and sensitivity analyses revealed 22 significant causal associations. In particular, there is a suggestive causality between the family Clostridiaceae1 (IVW: β = 0.063, P = 0.034), the genus Butyrivibrio (IVW: β = 0.029, P = 0.031), and the family Alcaligenaceae (IVW: β=-0.070, P = 0.014) and adiponectin. Stronger causal effects with leptin were found for the genus Enterorhabdus (IVW: β=-0.073, P = 0.038) and the genus Lachnospiraceae (NK4A136 group) (IVW: β=-0.076, P = 0.01). Eight candidate bacterial groups were found to be associated with sOB-R, with the phylum Firmicutes (IVW: β = 0.235, P = 0.03) and the order Clostridiales (IVW: β = 0.267, P = 0.028) being of more interest. In addition, the genus Roseburia (IVW: β = 0.953, P = 0.022) and the order Lactobacillales (IVW: β=-0.806, P = 0.042) were suggestive of an association with PAI-1.

CONCLUSION

This study reveals a causal relationship between the gut microbiota and circulating adipokines and may help to offer novel insights into the prevention of abnormal concentrations of circulating adipokines and obesity-related diseases.

The gut microbiota-derived metabolite indole-3-propionic acid enhances leptin sensitivity by targeting STAT3 against diet-induced obesity

Obesity is associated with the gut microbiome. Here, we report that gut commensal Clostridia bacteria regulate host energy balance through the tryptophan-derived metabolite indole-3-propionic acid (IPA). IPA acts as an endogenous leptin sensitiser to counteract obesity. Mechanistically, IPA is secreted from the gut into the circulation, and then targets to the STAT3 in the hypothalamic appetite regulation centre, promoting its phosphorylation and nuclear translocation, which enhances the body's response to leptin, and regulates the balance between appetite and energy metabolism. The in vitro pull-down assays involving site-directed mutagenesis demonstrate that Trp623 in the SH2 domain is the key binding site for STAT3-IPA interaction. High-fat diet (HFD), rather than genetic factors, induces excessive secretion of antimicrobial peptides by Paneth cells, inhibiting the growth of Clostridia in the gut and resulting in decreased production of the beneficial metabolite IPA. IPA or Clostridium sporogenes supplement effectively controls weight gain, improves glucose metabolism, and reduces inflammation in DIO mice. IPA fails to achieve such effects in ob/ob mice, while exogenous leptin administration restores the therapeutic effect of IPA. Our study suggests that the IPA-based gut-brain axis regulates host metabolism, and supplementation with microbiome-derived IPA could be a promising intervention strategy for treating obesity.

Leptin limits hepatic lipid accumulation and inflammation via vagal activation of the JAK2-STAT3/AMPK pathway

Non-Alcoholic Fatty Liver Disease (NAFLD) begins with hepatic lipid accumulation, and leptin has antisteatosis properties. In this study, we investigated the effects of leptin on hepatic steatosis and inflammation through the vagal pathway independently of the inhibitory effect of food intake. Male Sprague-Dawley rats were matched for food intake after the high-fat diet (HFD)-induced obesity model and were injected intraperitoneally with leptin or leptin + lidocaine for 6 weeks. Control rats received equal volumes of saline. Adipose tissue mass, NAFLD activity scores (NAS), hepatic inflammatory factors, hepatic triglyceride content and hepatic lipid metabolism-related protein levels were evaluated. Leptin ameliorated HFD-induced hepatic lipid accumulation, improved NAS, and decreased tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and monocyte chemotactic protein-1 (MCP-1) levels in the presence of matched intake. Lidocaine decreased the phosphorylation of signal transducer and activator of transcription 3 (p-STAT3) expression in the nucleus tractus solitarius (NTS) and abrogated the leptin-mediated improvement. Leptin increased hypothalamic phosphorylated Janus kinase 2 (p-JAK2) and p-STAT3 expression, as well as the expression of mitochondrial respiratory chain-related genes. Leptin also increased hepatic phosphorylated adenosine 5'-monophosphate-activated protein kinase (p-AMPK) expression and phosphorylation of its downstream target acetyl Co A carboxylase 1 (ACC1), reducing de novo lipogenesis. Our results suggest that leptin ameliorated hepatic lipid accumulation and inflammation by activating the JAK2-STAT3/AMPK pathway through the vagal pathway independently of the inhibitory effect of ingestion. Leptin has the potential to be a drug for early NAFLD treatment.

Plasma Non-Esterified Fatty Acid Levels Throughout Childhood and Its Relationship with Leptin Levels in Children

Background/Objective: The relationship of non-esterified fatty acid (NEFA) levels with obesity and obesity-related alterations shows age-dependent variability in children. Leptin, with an important role in energy homeostasis and lipid metabolism, may be related to NEFA levels throughout the first decades of life. This cross-sectional study aims to analyse plasma NEFA levels in children of different ages and evaluate the relationship of leptin with NEFA levels depending on age. Methods: The study sample included 818 prepubertal children (age 6-8 years) and 762 adolescents (age 13-16 years). NEFA levels were measured using the Wako NEFA-C kit. Insulin and leptin levels were determined by IRMA and ELISA, respectively, using commercial kits. Results: The results of the study were found to show that NEFA levels were significantly higher (p < 0.001) in prepubertal children than in children aged 13 to 16 years (0.68 ± 0.3 mmol/L vs. 0.42 ± 0.2 mmol/L, respectively, in males; 0.71 ± 0.3 mmol/L vs. 0.44 ± 0.2 mmol/L, respectively, in females), showing a progressive decrease according to years of life in this cohort of adolescent in both sexes. Leptin and insulin correlated negatively with NEFA levels in younger children but not in older participants. The negative association between NEFA levels and leptin occurring in prepubertal children remained significant when adjusting for insulin. Conclusions: Besides reporting that NEFA levels decrease between the prepubertal age and adolescence, our findings indicate that, in children aged 6-8 years, leptin is associated with NEFA levels, independently of insulin. However, this relationship is not present in older children. Further studies analysing these associations according to pubertal status would be useful to deepen our understand of these findings.

The skeleton: an overlooked regulator of systemic glucose metabolism in cancer?

Recent discoveries demonstrated the skeleton's role as an endocrine organ regulating whole-body glucose homeostasis. Glucose metabolism is critical for rapid cell proliferation and tumour growth through increasing glucose uptake and fermentation of glucose to lactate despite being in an aerobic environment. This hypothesis paper discusses emerging evidence on how bones can regulate whole-body glucose homeostasis with potential to impact on tumour growth and proliferation. Moreover, it proposes a clinical link between bone glucose metabolism and prognosis of cancer based on recent clinical trial data. Targeting metabolic pathways related with classic glucose metabolism and also bone metabolism, novel methods of cancer therapy and treatment could be developed. This paper objective is to highlight the need for future research on this altered metabolism with potential to change future management of cancer patients.

Western diet promotes endometriotic lesion growth in mice and induces depletion of Akkermansia muciniphila in intestinal microbiota

BACKGROUND

Endometriosis, affecting 10% of women in their reproductive years, remains poorly understood. Both individual and environmental unexplained factors are implicated in this heterogenous condition. This study aims to examine the influence of a Western diet on endometriosis lesion development in mice and to uncover the mechanisms involved.

METHODS

Mice were fed either a control diet or a Western diet (high in fatty acids and low in fiber) for 4 weeks. Endometriosis was then surgically induced, and lesion development was monitored by ultrasound. After 7 weeks, the mice were sacrificed for analysis of lesion characteristics through RT-qPCR, immunohistochemistry, and flow cytometry. Additionally, the intestinal microbiota was assessed using 16S rRNA gene sequencing.

RESULTS

Mice on the Western diet developed lesions that were significantly twice as large compared to those on the control diet. These lesions exhibited greater fibrosis and proliferation, alongside enhanced macrophage activity and leptin pathway expression. Changes in the intestinal microbiota were significantly noted after endometriosis induction, regardless of diet. Notably, mice on the Western diet with the most substantial lesions showed a loss of Akkermansia Muciniphila in their intestinal microbiota.

CONCLUSIONS

A Western diet significantly exacerbates lesion size in a mouse model of endometriosis, accompanied by metabolic and immune alterations. The onset of endometriosis also leads to substantial shifts in intestinal microbiota, suggesting a potential link between diet, intestinal health, and endometriosis development.

Novel perspectives on leptin in osteoarthritis: Focus on aging

Osteoarthritis (OA) is a common chronic joint disease characterized by articular cartilage degeneration, subchondral sclerosis, synovitis, and osteophyte formation. OA is associated with disability and impaired quality of life, particularly among the elderly. Leptin, a 16-kD non-glycosylated protein encoded by the obese gene, is produced on a systemic and local basis in adipose tissue and the infrapatellar fat pad located in the knee. The metabolic mechanisms employed by leptin in OA development have been widely studied, with attention being paid to aging as a corroborative risk factor for OA. Hence, in this review, we have attempted to establish a potential link between leptin and OA, by focusing on aging-associated mechanisms and proposing leptin as a potential diagnostic and therapeutic target in aging-related mechanisms of OA that may provide fruitful guidance and emphasis for future research.

Human mesenchymal stem/stromal cell based-therapy in diabetes mellitus: experimental and clinical perspectives

Diabetes mellitus (DM), a chronic metabolic disease, poses a significant global health challenge, with current treatments often fail to prevent the long-term disease complications. Mesenchymal stem/stromal cells (MSCs) are, adult progenitors, able to repair injured tissues, exhibiting regenerative effects and immunoregulatory and anti-inflammatory responses, so they have been emerged as a promising therapeutic approach in many immune-related and inflammatory diseases. This review summarizes the therapeutic mechanisms and outcomes of MSCs, derived from different human tissue sources (hMSCs), in the context of DM type 1 and type 2. Animal model studies and clinical trials indicate that hMSCs can facilitate pleiotropic actions in the diabetic milieu for improved metabolic indices. In addition to modulating abnormally active immune system, hMSCs can ameliorate peripheral insulin resistance, halt beta-cell destruction, preserve residual beta-cell mass, promote beta-cell regeneration and insulin production, support islet grafts, and correct lipid metabolism. Moreover, hMSC-free derivatives, importantly extracellular vesicles, have shown potent experimental anti-diabetic efficacy. Moreover, the review discusses the diverse priming strategies that are introduced to enhance the preclinical anti-diabetic actions of hMSCs. Such strategies are recommended to restore the characteristics and functions of MSCs isolated from patients with DM for autologous implications. Finally, limitations and merits for the wide spread clinical applications of MSCs in DM such as the challenge of autologous versus allogeneic MSCs, the optimal MSC tissue source and administration route, the necessity of larger clinical trials for longer evaluation duration to assess safety concerns, are briefly presented.

Role of leptin and adiponectin in the pathogenesis of post-transplant diabetes mellitus

Solid organ transplantation is a life-saving treatment for patients with end-stage organ failure, but it poses unique challenges due to metabolic and immunological changes in recipients. One significant complication is post-transplant diabetes mellitus (PTDM), which affects a variety of solid organ recipients. Leptin, a hormone produced by adipose tissue, regulates appetite and affects glucose metabolism. High leptin levels are associated with the development of PTDM, especially in kidney transplant recipients. Adiponectin, another adipokine, increases insulin sensitivity and has anti-diabetic properties. Low adiponectin levels are associated with insulin resistance and increase the risk of PTDM. As the incidence of PTDM increases due to the increased life expectancy among transplant patients, understanding the role of adipokines such as leptin and adiponectin becomes crucial for early detection and treatment. Additional studies on other adipokines may also provide valuable information on the pathogenesis of PTDM.

Dissecting the importance and origin of circulating myokines in gastric cancer cachexia

Background

Some experimental data suggest that myokines may play an important role in developing cancer-associated cachexia (CAC), but their relevance in humans remains poorly explored. In our study, we tested the hypothesis that circulating myokines are associated with the pathogenesis of CAC in a model population of gastric cancer.

Methods

A group of 171 treatment naïve patients with adenocarcinoma of the stomach were prospectively examined. Cachexia was defined as weight loss >5% or weight loss >2% with either BMI <20 kg/m2 or sarcopenia. A panel of 19 myokines was measured in portal and peripheral blood as well as tumour tissue and surrounding gastric mucosa. Moreover, a serum proteomic signature of cachexia was identified by a label-free quantitative proteomics with a nano LC-MS/MS system and stored in a ProteomeXchange database (PXD049334).

Results

One hundred (58%) patients were diagnosed with CAC. The concentrations of fatty acid-binding protein 3 (FABP3), follistatin-like 1 protein (FSTL-1), interleukin 6 (IL 6), and interleukin 8 (IL 8) were significantly higher in the peripheral blood of cachectic subjects, while leptin levels were lower. Of all the evaluated myokines, tumour tissues showed higher expression levels only for IL-15 and myostatin. However, the analysis of paired samples failed to demonstrate a decreasing concentration gradient between the portal and peripheral blood for any of the myokines, evidencing against their release by the primary tumour. Proteomic analysis identified 28 proteins upregulated and 24 downregulated in the peripheral blood of patients with cachexia. Differentially expressed proteins and 5 myokines with increased serum levels generated a significant protein-protein interaction network.

Conclusions

Our study provides clinical evidence that some myokines are involved in the pathogenesis of cachexia and are well integrated into the regulatory network of circulating blood proteins identified among cachectic patients with gastric cancer.

Adipokines in the Crosstalk between Adipose Tissues and Other Organs: Implications in Cardiometabolic Diseases

Adipose tissue was previously regarded as a dormant organ for lipid storage until the identification of adiponectin and leptin in the early 1990s. This revelation unveiled the dynamic endocrine function of adipose tissue, which has expanded further. Adipose tissue has emerged in recent decades as a multifunctional organ that plays a significant role in energy metabolism and homeostasis. Currently, it is evident that adipose tissue primarily performs its function by secreting a diverse array of signaling molecules known as adipokines. Apart from their pivotal function in energy expenditure and metabolism regulation, these adipokines exert significant influence over a multitude of biological processes, including but not limited to inflammation, thermoregulation, immune response, vascular function, and insulin sensitivity. Adipokines are pivotal in regulating numerous biological processes within adipose tissue and facilitating communication between adipose tissue and various organs, including the brain, gut, pancreas, endothelial cells, liver, muscle, and more. Dysregulated adipokines have been implicated in several metabolic diseases, like obesity and diabetes, as well as cardiovascular diseases. In this article, we attempted to describe the significance of adipokines in developing metabolic and cardiovascular diseases and highlight their role in the crosstalk between adipose tissues and other tissues and organs.

The hypoglycemic effect of enzymatic modified dietary fiber from bamboo shoot on type 2 diabetes rats

Bamboo shoot is a healthy food rich in dietary fiber (DF). However, its highly insoluble DF and fibrous texture limit its application in industrially processed foods. To achieve industrial processing of bamboo shoot, cellulase was used to improve the physical characteristics of bamboo shoot DF in this study. After enzymatic hydrolysis, the content of soluble DF (SDF) of bamboo shoot increased by 99.28% (from 5.53% to 11.02%) significantly (p < 0.01). At the same time, the effect of enzymatic-modified bamboo SDF (EMBSDF) on streptozotocin-induced type 2 diabetes rats was explored. Results demonstrated that the high dose of EMBSDF (312.8 mg/kg) treated rats showed significant improvements in terms of glucose tolerance and insulin sensitivity (p < 0.01) compared with the diabetes rats. Meantime, it was observed that the levels of glucagon-like peptide-1, adiponectin and interleukin-4 of high dose of EMBSDF compared with diabetes rats were increased (p < 0.01) by 57.79%, 159.13%, and 6.17%, respectively. The tumor necrosis factor-α, C-reactive protein, and leptin levels were decreased (p < 0.01) by 62.89%, 31.53%, and 7.84%, respectively. Furthermore, apparent kidney and pancreas histology improvements were found in high-dose and mid-dose EMBSDF-treated diabetes rats. These results indicated that the modified DF significantly improved diabetes.

Day and Night Reversed Feeding Aggravates High-Fat Diet-Induced Abnormalities in Intestinal Flora and Lipid Metabolism in Adipose Tissue of Mice

BACKGROUND

The incongruity between dietary patterns and the circadian clock poses an elevated risk for metabolic health issues, particularly obesity and associated metabolic disorders. The intestinal microflora engages in regulating various physiological functions of the host through its metabolites.

OBJECTIVES

This study aimed to investigate the impact of reversed feeding schedules during the day and night on intestinal flora and lipid metabolism in high-fat diet-induced obese mice.

METHODS

Mice aged 8-10 wk were subjected to either daytime or nighttime feeding and were administered a control or high-fat diet for 18 wk. At the end of the experiment, various assessments were conducted, including analysis of serum biochemic indices, histologic examination, evaluation of gene and protein expression in adipose tissue, and scrutiny of changes in intestinal microbial composition.

RESULTS

The results showed that day-night reversed feeding caused an increase in fasting blood glucose and exacerbated the high-fat diet-induced weight gain and lipid abnormalities. The mRNA expression levels of Leptin and Dgat1 were increased by day-night reversed feeding, which also reduced the expression level of adiponectin under the high-fat diet. Additionally, there was a significant increase in the protein concentrations of PPARγ, SREBP1c, and CD36. Inverted feeding schedules led to a reduction in intestinal microbial diversity, an increase in the abundance of inflammation-related bacteria, such as Coriobacteriaceae_UCG-002, and a suppression of beneficial bacteria, including Akkermansia, Candidatus_Saccharimonas, Anaeroplasma, Bifidobacterium, Carnobacterium, and Odoribacter. Acinetobacter exhibited a significant negative correlation with Leptin and Fasn, suggesting potential involvement in the regulation of lipid metabolism.

CONCLUSIONS

The results elucidated the abnormalities of lipid metabolism and intestinal flora caused by day-night reversed feeding, which exacerbates the adverse effects of a high-fat diet on lipid metabolism and intestinal microflora. This reversal in feeding patterns may disrupt both intestinal and lipid metabolism homeostasis by altering the composition and abundance of intestinal microflora in mice.

The influence of nutritional status, lipid profile, leptin concentration and polymorphism of genes encoding leptin and neuropeptide Y on the effectiveness of immunotherapy in advanced NSCLC patients

INTRODUCTION

Neuropeptide Y is a neurotransmitter in the nervous system and belongs to the orexigenic system that increases appetite. Its excessive secretion leads to obesity. Leptin is a pro-inflammatory adipokine (produced in adipose tissue) induced in obesity and may mediate increased antitumor immunity in obesity (including the promotion of M1 macrophages). Leptin and neuropeptide Y gene polymorphisms, causing increased leptin levels and the occurrence of obesity, and lipid profile disorders, may increase the effectiveness of immunotherapy.

MATERIALS AND METHODS

In 121 patients with advanced NSCLC without mutations in the EGFR gene and rearrangements of the ALK and ROS1 genes, undergoing immunotherapy (1st and 2nd line of treatment) or chemoimmunotherapy (1st line of treatment), we assessed BMI, lipid profile, PD-L1 expression on cancer cells using the immunohistochemical method (clone SP263 antibody), leptin concentration in blood serum by ELISA, polymorphisms in the promoter region of the genes for leptin (LEP) and neuropeptide Y (NPY) by real-time PCR.

RESULTS

Leptin concentration was significantly higher in obese patients than in patients with normal or low weight (p = 0.00003) and in patients with disease stabilization compared to patients with progression observed during immunotherapy (p = 0.012). Disease control occurred significantly more often in patients with the GA or AA genotype than patients with the GG genotype in the rs779039 polymorphism of the LEP gene. The median PFS in the entire study group was five months (95% CI: 3-5.5), and the median OS was 12 months (95% CI: 8-16). Median PFS was highest in patients with TPS ≥ 50% (6.5 months) and in obese patients (6.6 months). Obese patients also had a slightly longer median OS compared to other patients (23.8 vs. 13 months). The multivariate Cox logistic regression test showed that the only factor reducing the risk of progression was TPS ≥ 50% (HR = 0.6068, 95% CI: 0.4001-0.9204, p = 0, 0187), and the only factor reducing the risk of death was high leptin concentration (HR = 0.6743, 95% CI: 0.4243-1.0715, p = 0.0953).

CONCLUSION

Assessment of nutritional status, serum leptin concentration and polymorphisms in the LEP gene may be of additional importance in predicting the effectiveness of immunotherapy and chemoimmunotherapy in patients with advanced NSCLC.

Body fat and circulating leptin levels in the captive short-beaked echidna (Tachyglossus aculeatus)

It is possible that the reproductive strategy of the short-beaked echidna is related to seasonal changes in fat deposition and energy availability, regulated by seasonal changes in endocrine function. We predicted that circulating leptin levels would be directly proportional to adiposity during most of the year, but that a change in this relationship would occur during the pre-breeding season to allow increased fat deposition. To test this hypothesis, we made use of a captive colony of echidnas to describe and quantify changes in fat distribution and the adipostatic hormone leptin. First we assessed seasonal changes in circulating leptin levels, body mass and adiposity for three male and three female adult echidnas maintained on a standard diet. Second, we explored the relationship between circulating leptin levels and increased caloric intake for an additional five adult female echidnas that were provided with supplemented nutrition. Third we visualised fat distribution in male and female adult echidnas using magnetic resonance imaging (MRI) before and after the breeding season, to determine where fat is deposited in this species. For echidnas maintained on the standard diet, there were no seasonal changes in body mass, body fat or plasma leptin levels. However, female echidnas provided with supplemented nutrition had significantly elevated plasma leptin levels during the breeding season, compared to the pre-and post- breeding periods. MRI showed substantial subcutaneous fat depots extending dorso-laterally from the base of the skull to the base of the tail, in both sexes. Pre-breeding season, both sexes had considerable fat deposition in the pelvic/rump region, whilst the female echidna accumulated most fat in the abdominal region. This study shows that male and female echidnas accumulate body fat in the pelvic/rump and the abdominal regions, respectively and that circulating leptin may promote fattening in female echidnas during the breeding season by means of leptin resistance. However, further research is required to evaluate the precise relationship between seasonal changes in leptin and adiposity.

LEP inhibits intramuscular adipogenesis through the AMPK signaling pathway in vitro

Leptin can indirectly regulate fatty-acid metabolism and synthesis in muscle in vivo and directly in incubated muscle ex vivo. In addition, non-synonymous mutations in the bovine leptin gene (LEP) are associated with carcass intramuscular fat (IMF) content. However, the effects of LEP on lipid synthesis of adipocytes have not been clearly studied at the cellular level. Therefore, this study focused on bovine primary intramuscular preadipocytes to investigate the effects of LEP on the proliferation and differentiation of intramuscular preadipocytes, as well as its regulatory mechanism in lipid synthesis. The results showed that both the LEP and leptin receptor gene (LEPR) were highly expressed in IMF tissues, and their mRNA expression levels were positively correlated at different developmental stages of intramuscular preadipocytes. The overexpression of LEP inhibited the proliferation and differentiation of intramuscular preadipocytes, while interference with LEP had the opposite effect. Additionally, LEP significantly promoted the phosphorylation level of AMPKα by promoting the protein expression of CAMKK2. Meanwhile, rescue experiments showed that the increasing effect of AMPK inhibitors on the number of intramuscular preadipocytes was significantly weakened by the overexpression of LEP. Furthermore, the overexpression of LEP could weaken the promoting effect of AMPK inhibitor on triglyceride content and droplet accumulation, and prevent the upregulation of adipogenic protein expression (SREBF1, FABP4, FASN, and ACCα) caused by AMPK inhibitor. Taken together, LEP acted on the AMPK signaling pathway by regulating the protein expression of CAMKK2, thereby downregulating the expression of proliferation-related and adipogenic-related genes and proteins, ultimately reducing intramuscular adipogenesis.

Mechanisms of regulation of glycolipid metabolism by natural compounds in plants: effects on short-chain fatty acids

BACKGROUND

Natural compounds can positively impact health, and various studies suggest that they regulate glucose‒lipid metabolism by influencing short-chain fatty acids (SCFAs). This metabolism is key to maintaining energy balance and normal physiological functions in the body. This review explores how SCFAs regulate glucose and lipid metabolism and the natural compounds that can modulate these processes through SCFAs. This provides a healthier approach to treating glucose and lipid metabolism disorders in the future.

METHODS

This article reviews relevant literature on SCFAs and glycolipid metabolism from PubMed and the Web of Science Core Collection (WoSCC). It also highlights a range of natural compounds, including polysaccharides, anthocyanins, quercetins, resveratrols, carotenoids, and betaines, that can regulate glycolipid metabolism through modulation of the SCFA pathway.

RESULTS

Natural compounds enrich SCFA-producing bacteria, inhibit harmful bacteria, and regulate operational taxonomic unit (OTU) abundance and the intestinal transport rate in the gut microbiota to affect SCFA content in the intestine. However, most studies have been conducted in animals, lack clinical trials, and involve fewer natural compounds that target SCFAs. More research is needed to support the conclusions and to develop healthier interventions.

CONCLUSIONS

SCFAs are crucial for human health and are produced mainly by the gut microbiota via dietary fiber fermentation. Eating foods rich in natural compounds, including fruits, vegetables, tea, and coarse fiber foods, can hinder harmful intestinal bacterial growth and promote beneficial bacterial proliferation, thus increasing SCFA levels and regulating glucose and lipid metabolism. By investigating how these compounds impact glycolipid metabolism via the SCFA pathway, novel insights and directions for treating glucolipid metabolism disorders can be provided.

Genetic and Epigenetic Landscape for Drug Development in Polycystic Ovary Syndrome

The treatment of polycystic ovary syndrome (PCOS) faces challenges as all known treatments are merely symptomatic. The US Food and Drug Administration has not approved any drug specifically for treating PCOS. As the significance of genetics and epigenetics rises in drug development, their pivotal insights have greatly enhanced the efficacy and success of drug target discovery and validation, offering promise for guiding the advancement of PCOS treatments. In this context, we outline the genetic and epigenetic advancement in PCOS, which provide novel insights into the pathogenesis of this complex disease. We also delve into the prospective method for harnessing genetic and epigenetic strategies to identify potential drug targets and ensure target safety. Additionally, we shed light on the preliminary evidence and distinctive challenges associated with gene and epigenetic therapies in the context of PCOS.

Leptin, Ghrelin, Irisin, Asprosin and Subfatin Changes in Obese Women: Effect of Exercise and Different Nutrition Types

Background and Objectives: In this study, the effects of a six-week training program and various diets on subfatin, asprosin, irisin, leptin, ghrelin and the lipid profile were investigated in overweight women. Materials and Methods: A total of 78 women voluntarily participated in the study. Groups: The study was divided into eight groups: Healthy Control, Obese Control, Obese + Vegetarian, Obese + Ketogenic, Obese + Intermittent Fasting, Obese + Exercise + Vegetarian, Obese + Exercise + Ketogenic and Obese + Exercise + Intermittent Fasting. While there was no intervention in the healthy and obese control groups, the other groups followed predetermined exercise and diet programs for 6 weeks. Blood samples were taken from the participants in the research group twice (before and after the interventions). An autoanalyzer was used to determine the lipid profile in the blood samples taken, and the ELISA method was used to analyze other parameters. Results: Overall, a significant difference was found in the values of weight, BMI, subfatin, ghrelin, leptin, cholesterol, triglyceride, HDL and LDL as a result of the exercise and diet interventions (p < 0.05). There was no significant difference in asprosin and irisin values (p > 0.05). Conclusions: In conclusion, regular exercise and dietary interventions in obese women can regulate lipid profile, ghrelin, leptin and asprosin levels, and increasing irisin with exercise can activate lipid metabolism and support positive changes in lean mass.

Leptin combined with withaferin A boost posthemorrhagic neurogenesis via activation of STAT3/SOCS3 pathway

Neurogenesis as a potential strategy to improve the consequences of intracerebral hemorrhage (ICH). The current study investigates the effects of withaferin A (WFA) in combination with leptin (LEP) on ICH and neurogenesis mechanisms. LEP levels were dramatically reduced on days 7 and 14 following ICH insults in mice, but continuous WFA therapy significantly improved the potency of intrinsic LEP on day 14 after ICH. Furthermore, WFA combined with LEP enhances intrinsic neurogenesis and lessen motor deficits and long-term cognitive outcomes after ICH. In parallel, leptin deficiency in ob/ob mice limits enhancement of neurogenesis following ICH in response to WFA combined with LEP treatment. Importantly, the functional recovery conferred by WFA combined with LEP after ICH was inhibited by neurogenesis suppression. Mechanistically, this study unveiled that the signal transducer and activator of transcription-3 (STAT3) / suppressor of cytokine signaling-3 (SOCS3) pathway is a critical signaling pathway through which WFA combined with LEP treatment promotes intrinsic neurogenesis after ICH. Collectively, the results of this study elucidate the neuroprotective effects of WFA and LEP in ICH, and highlight a potential approach for ICH cell therapy.

Implication of the endocannabidiome and metabolic pathways in fragile X syndrome pathophysiology

Fragile X Syndrome (FXS) results from the silencing of the FMR1 gene and is the most prevalent inherited cause of intellectual disability and the most frequent monogenic cause of autism spectrum disorder. It is well established that Fragile X individuals are subjected to a wide array of comorbidities, ranging from cognitive, behavioural, and medical origin. Furthermore, recent studies have also described metabolic impairments in FXS individuals. However, the molecular mechanisms linking FMRP deficiency to improper metabolism are still misunderstood. The endocannabinoidome (eCBome) is a lipid-based signalling system that regulates several functions across the body, ranging from cognition, behaviour and metabolism. Alterations in the eCBome have been described in FXS animal models and linked to neuronal hyperexcitability, a core deficit of the disease. However, the potential link between dysregulation of the eCBome and altered metabolism observed in FXS remains unexplored. As such, this review aims to overcome this issue by describing the most recent finding related to eCBome and metabolic dysfunctions in the context of FXS. A better comprehension of this association will help deepen our understanding of FXS pathophysiology and pave the way for future therapeutic interventions.

Maternal dietary fatty acid composition and content prior to and during pregnancy and lactation influences serum profile, liver phenotype and hepatic miRNA expression in young male and female offspring

This study aimed to investigate whether modifying the pre-gestational lipid content could mitigate metabolic damage in offspring from dams exposed to a high-fat (HF) diet before conception and during pregnancy and lactation, with a focus on sex-specific outcomes. Specific effects of maternal normolipidic diets on offspring were also assessed. Female Wistar rats received control (C) or HF diets before conception. During pregnancy and lactation, females were distributed in five groups: C-C, HF-HF, HF-C, HF-saturated (HF-S) or HF-polyunsaturated n-3 group (HF-P). Saturated and PUFA n-3 diets were normolipidic. In 21-day-old offspring, corporal parameters, adiposity, serum metabolites, OGTT, liver phenotype, and miR-34a-5p hepatic expression were determined. Pre-gestational HF diet impaired glycemic response in females, independent of any change in body weight. Female and male offspring from dams continuously exposed to HF diet exhibited hyperglycemia, increased adiposity, and disrupted serum lipid profiles. Male offspring showed increased hepatic fat accumulation and miR-34a-5p expression. Shifting maternal dietary lipid content to normolipidic diets restored offspring's phenotype; however, decreased SIRT1, IRβ and IRS1 expression in offspring from dams exposed to HF diet before conception suggested early indicators of glucose metabolism damage. Our findings indicated a pronounced metabolic impact on males. In conclusion, glucose tolerance impairment in females before conception disturbed intrauterine environment, influencing in offspring's phenotype. Modifying maternal dietary lipid content mitigated effects of pre-gestational HF diet exposure on young offspring. Nevertheless, decreased hepatic levels of critical insulin signaling proteins indicated that independently of the maternal diet, pre-existing HF diet-induced glucose intolerance before conception may adversely program the offspring's phenotype.

The Gut Microbial Regulation of Epigenetic Modification from a Metabolic Perspective

Obesity is a global health challenge that has received increasing attention in contemporary research. The gut microbiota has been implicated in the development of obesity, primarily through its involvement in regulating various host metabolic processes. Recent research suggests that epigenetic modifications may serve as crucial pathways through which the gut microbiota and its metabolites contribute to the pathogenesis of obesity and other metabolic disorders. Hence, understanding the interplay between gut microbiota and epigenetic mechanisms is crucial for elucidating the impact of obesity on the host. This review primarily focuses on the understanding of the relationship between the gut microbiota and its metabolites with epigenetic mechanisms in several obesity-related pathogenic mechanisms, including energy dysregulation, metabolic inflammation, and maternal inheritance. These findings could serve as novel therapeutic targets for probiotics, prebiotics, and fecal microbiota transplantation tools in treating metabolic disruptions. It may also aid in developing therapeutic strategies that modulate the gut microbiota, thereby regulating the metabolic characteristics of obesity.

Serum levels of leptin, ghrelin putative peptide YY-3 in patients with fetal alcohol spectrum disorders

Fetal alcohol spectrum disorders (FASD) are a severe developmental condition resulting from exposure to alcohol during pregnancy. The aim of this study was to examine the concentrations of hormones involved in appetite regulation-ghrelin, leptin, and putative peptide YY-3 (PYY)-in the serum of individuals with FASD. Additionally, we investigated the relationship between these hormone levels and clinical indicators. We conducted an enzyme-linked immunosorbent assay on samples collected from 62 FASD patients and 23 individuals without the condition. Our results revealed a significant decrease in leptin levels among FASD patients compared to the control group (5.124 vs. 6.838 ng/mL, p = 0.002). We revealed no statistically significant differences in the levels of other hormones studied (ghrelin and PYY). Comparisons of hormone levels were also conducted in three subgroups: FAS, neurobehavioral disorders associated with prenatal alcohol exposure and FASD risk, as well as by sex. Assignment to FASD subgroups indicated changes only for leptin. Sex had no effect on the levels of hormones. Moreover, the levels of leptin showed a negative correlation with cortisol levels and a positive correlation with BMI and proopiomelanocortin. Alterations in appetite regulation can contribute to the improper development of children with FASD, which might be another factor that should be taken into consideration in the proper treatment of patients.

Effects of Combined Low-Dose Spironolactone Plus Vitamin E versus Vitamin E Monotherapy on Lipidomic Profile in Non-Alcoholic Fatty Liver Disease: A Post Hoc Analysis of a Randomized Controlled Trial

Background/Objectives: Lipid dysmetabolism seems to contribute to the development and progression of nonalcoholic fatty liver disease (NAFLD). Our aim was to compare serum lipidomic profile between patients with NAFLD having received monotherapy with vitamin E (400 IU/d) and those having received combination therapy with vitamin E (400 IU/d) and low-dose spironolactone (25 mg/d) for 52 weeks. Methods: This was a post hoc study of a randomized controlled trial (NCT01147523). Serum lipidomic analysis was performed in vitamin E monotherapy group (n = 15) and spironolactone plus vitamin E combination therapy group (n = 12). We employed an untargeted liquid chromatography-mass spectrometry lipid profiling approach in positive and negative ionization mode. Results: Univariate analysis revealed 36 lipid molecules statistically different between groups in positive mode and seven molecules in negative mode. Multivariate analysis in negative mode identified six lipid molecules that remained robustly different between groups. After adjustment for potential confounders, including gender, omega-3 supplementation, leptin concentration and homeostasis model assessment-insulin resistance (HOMA-IR), four lipid molecules remained significant between groups: FA 20:5, SM 34:2;O2, SM 42:3;O2 and CE 22:6, all being higher in the combination treatment group. Conclusions: The combination of spironolactone with vitamin E led to higher circulating levels of four lipid molecules than vitamin E monotherapy, after adjustment for potential confounders. Owing to very limited relevant data, we could not support that these changes in lipid molecules may be beneficial or not for the progression of NAFLD. Thus, mechanistic studies are warranted to clarify the potential clinical significance of these findings.

Sodium-Glucose Cotransporter Inhibitors: Cellular Mechanisms Involved in the Lipid Metabolism and the Treatment of Chronic Kidney Disease Associated with Metabolic Syndrome

Metabolic syndrome (MetS) is a multifactorial condition that significantly increases the risk of cardiovascular disease and chronic kidney disease (CKD). Recent studies have emphasized the role of lipid dysregulation in activating cellular mechanisms that contribute to CKD progression in the context of MetS. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have demonstrated efficacy in improving various components of MetS, including obesity, dyslipidemia, and insulin resistance. While SGLT2i have shown cardioprotective benefits, the underlying cellular mechanisms in MetS and CKD remain poorly studied. Therefore, this review aims to elucidate the cellular mechanisms by which SGLT2i modulate lipid metabolism and their impact on insulin resistance, mitochondrial dysfunction, oxidative stress, and CKD progression. We also explore the potential benefits of combining SGLT2i with other antidiabetic drugs. By examining the beneficial effects, molecular targets, and cytoprotective mechanisms of both natural and synthetic SGLT2i, this review provides a comprehensive understanding of their therapeutic potential in managing MetS-induced CKD. The information presented here highlights the significance of SGLT2i in addressing the complex interplay between metabolic dysregulation, lipid metabolism dysfunction, and renal impairment, offering clinicians and researchers a valuable resource for developing improved treatment strategies and personalized approaches for patients with MetS and CKD.

Growth hormone improves insulin resistance in visceral adipose tissue after duodenal-jejunal bypass by regulating adiponectin secretion

BACKGROUND

The mechanism of improvement of type 2 diabetes after duodenal-jejunal bypass (DJB) surgery is not clear.

AIM

To study the morphological and functional changes in adipose tissue after DJB and explore the potential mechanisms contributing to postoperative insulin sensitivity improvement of adipose tissue in a diabetic male rat model.

METHODS

DJB and sham surgery was performed in a-high-fat-diet/streptozotocin-induced diabetic rat model. All adipose tissue was weighed and observed under microscope. Use inguinal fat to represent subcutaneous adipose tissue (SAT) and mesangial fat to represent visceral adipose tissue. RNA-sequencing was utilized to evaluate gene expression alterations adipocytes. The hematoxylin and eosin staining, reverse transcription-quantitative polymerase chain reaction, western blot, and enzyme-linked immunosorbent assay were used to study the changes. Insulin resistance was evaluated by immunofluorescence.

RESULTS

After DJB, whole body blood glucose metabolism and insulin sensitivity in adipose tissue improved. Fat cell volume in both visceral adipose tissue (VAT) and SAT increased. Compared to SAT, VAT showed more significantly functional alterations after DJB and KEGG analysis indicated growth hormone (GH) pathway and downstream adiponectin secretion were involved in metabolic regulation. The circulating GH and adiponectin levels and GH receptor and adiponectin levels in VAT increased. Cytological experiment showed that GH stimulated adiponectin secretion and improve insulin sensitivity.

CONCLUSION

GH improves insulin resistance in VAT in male diabetic rats after receiving DJB, possibly by increasing adiponectin secretion.

Transcriptomic profiling of Rana [Lithobates] catesbeiana back skin during natural and thyroid hormone-induced metamorphosis under different temperature regimes with particular emphasis on innate immune system components

As amphibians undergo thyroid hormone (TH)-dependent metamorphosis from an aquatic tadpole to the terrestrial frog, their innate immune system must adapt to the new environment. Skin is a primary line of defense, yet this organ undergoes extensive remodelling during metamorphosis and how it responds to TH is poorly understood. Temperature modulation, which regulates metamorphic timing, is a unique way to uncover early TH-induced transcriptomic events. Metamorphosis of premetamorphic tadpoles is induced by exogenous TH administration at 24 °C but is paused at 5 °C. However, at 5 °C a "molecular memory" of TH exposure is retained that results in an accelerated metamorphosis upon shifting to 24 °C. We used RNA-sequencing to identify changes in Rana (Lithobates) catesbeiana back skin gene expression during natural and TH-induced metamorphosis. During natural metamorphosis, significant differential expression (DE) was observed in >6500 transcripts including classic TH-responsive transcripts (thrb and thibz), heat shock proteins, and innate immune system components: keratins, mucins, and antimicrobial peptides (AMPs). Premetamorphic tadpoles maintained at 5 °C showed 83 DE transcripts within 48 h after TH administration, including thibz which has previously been identified as a molecular memory component in other tissues. Over 3600 DE transcripts were detected in TH-treated tadpoles at 24 °C or when tadpoles held at 5 °C were shifted to 24 °C. Gene ontology (GO) terms related to transcription, RNA metabolic processes, and translation were enriched in both datasets and immune related GO terms were observed in the temperature-modulated experiment. Our findings have implications on survival as climate change affects amphibia worldwide.

Comprehensive review on lipid metabolism and RNA methylation: Biological mechanisms, perspectives and challenges

Adipose tissue plays a crucial role in maintaining energy balance, regulating hormones, and promoting metabolic health. To address disorders related to obesity and develop effective therapies, it is essential to have a deep understanding of adipose tissue biology. In recent years, RNA methylation has emerged as a significant epigenetic modification involved in various cellular functions and metabolic pathways. Particularly in the realm of adipogenesis and lipid metabolism, extensive research is ongoing to uncover the mechanisms and functional importance of RNA methylation. Increasing evidence suggests that RNA methylation plays a regulatory role in adipocyte development, metabolism, and lipid utilization across different organs. This comprehensive review aims to provide an overview of common RNA methylation modifications, their occurrences, and regulatory mechanisms, focusing specifically on their intricate connections to fat metabolism. Additionally, we discuss the research methodologies used in studying RNA methylation and highlight relevant databases that can aid researchers in this rapidly advancing field.

Correlation between serum leptin level and sleep monitoring indexes in patients with obstructive sleep apnea hypopnea syndrome and its predictive value: a cross-sectional analysis

Objective

To investigate the association between serum leptin (LP) level and polysomnography (PSG) parameters in patients with obstructive sleep apnea hypopnea syndrome (OSAHS).

Methods

A cross-sectional study was conducted. The data of subjects who underwent PSG at hospital between January 2021 and December 2022 were collected retrospectively, 220 participants were included. The subjects were categorized into simple snoring group (n = 45), mild OSAHS group (n = 63), moderate OSAHS group (n = 52), and severe OSAHS group (n = 60). The general characteristics, PSG indices, and serological indices were collected retrospectively. Pearson correlation analysis was used to observe the correlation between serum LP level and PSG parameters. The value of serum LP level in predicting OSAHS was analyzed by receiver operating characteristic curve.

Results

The serum LP level was positively correlated with micro-arousal count, micro-arousal index (MAI), high apnea hypopnea index, times of blood oxygen decreased by≥3% and time in saturation lower 90%, and negatively correlated with lowest nocturnal oxygen saturation and mean oxygen saturation (p < 0.05). The area under the curve (AUC) of serum LP level in predicting the occurrence of OSAHS was 0.8276 (95% CI: 0.7713-0.8839), and when the Youden index was 0.587, the sensitivity was 72.00%, and the specificity was 86.67% (p < 0.0001). In the population with high MAI, the AUC of serum LP level in predicting the occurrence of OSAHS was 0.8825 (95% CI: 0.7833-0.9817), and when the Youden index was 0.690, the sensitivity was 79.00% and the specificity was 90.00% (p < 0.0001).

Conclusion

Serum LP level is associated with the severity of OSAHS. Serum LP level demonstrates a strong predictive value for the occurrence of OSAHS, particularly in population with high MAI.