Adiponectin, the past two decades

Adiponectin receptor agonist AdipoRon regulates glucose and lipid metabolism via PPARγ signaling pathway in hepatocytes of large yellow croaker (Larimichthys crocea)

Activation of adiponectin receptors (AdipoRs) has been shown to regulate glucose and lipid metabolism in mammalian hepatocytes. However, much less is known for their roles in fish. The current study demonstrated that AdipoRon, a small-molecule activator of AdipoRs, modulated glucose and lipid metabolism in large yellow croaker. In hepatocytes of large yellow croaker, AdipoRon upregulated the mRNA expression of adipors and appl1, while increasing phosphorylation levels of AMPK and AKT. These changes indicate the activation of AdipoR-mediated signaling. Furthermore, AdipoRon promoted glucose uptake, increased intracellular glucose content, as well as upregulated genes involved in glycogen synthesis and glycolysis whereas downregulated gluconeogenesis-related genes. On the other hand, AdipoRon facilitated free fatty acid (FFA) absorption by increasing the expression of fatty acid transport genes (fat/cd36, fatp1, and fabp11). It also enhanced triglyceride (TG) synthesis, evidenced by increased triglyceride levels and upregulation of dgat2 and PPARγ, which is consistent with the effect of adiponectin (APN) in large yellow croaker. Additional evidence suggested that inhibition of PPARγ with GW9662 reduced the effects of AdipoRon on glucose uptake and lipid metabolism, indicating that PPARγ is a key mediator in these metabolic regulations. Overall, AdipoRon was found to modulate multiple metabolic processes in hepatocytes of large yellow croaker via PPARγ signaling pathway, and these findings suggested that AdipoRon might contribute to beneficial effects on metabolic homeostasis in teleosts.

Obesity, White Adipose Tissue, and Adipokines Signaling in Male Reproduction

Currently, obesity is a global pandemic characterized by systemic metabolic complications that negatively impact several organs, including white adipose tissue (WAT) and the tissues of the male reproductive system. Since the discovery of leptin in 1994, WAT has been recognized as a dynamic endocrine organ for secreting a series of molecules with hormonal functions, collectively called adipokines. The link between obesity, WAT, adipokines, and the male reproductive system is direct and little explored. With changes in nutritional status, WAT undergoes morphofunctional changes, and the secretion of adipokines is altered, negatively impacting reproductive mechanisms, including steroidogenesis and spermatogenesis. In this review, we address in an updated way the structural and functional characteristics of WAT as well as the link between obesity and changes in the signaling pathways of the adipokines leptin, adiponectin, resistin, visfatin, apelin, chemerin, omentin-1, vaspin, and asprosin in male reproduction. Understanding the relationship between obesity, these adipokines, and reproductive dysfunction can contribute to new strategies for the treatment of subfertility and male infertility.

Effect of peripheral adiponectin on perioperative neurocognitive disorder via regulation of glucose metabolism in aged rats

Perioperative neurocognitive disorder (PND) is a significant complication affecting elderly patients after surgery, with limited effective interventions to improve its prognosis yet. We have found that decreased serum adiponectin (APN) and increased cerebrospinal fluid (CSF) lactate are involved in the pathophysiological process of PND in elderly patients. APN is known for its anti-insulin resistance property. In this study, we further explored the regulatory effects of APN on cerebral glucose metabolism in PND rats. Twelve-month-old male Sprague-Dawley rats were divided into 3 groups: the sham, PND (splenectomy) and PND+APN (50 mg/kg/day intragastrically) groups. ELISA, quantitative PCR and colorimetric analysis were conducted to analyze tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), pyruvate and lactate in serum, CSF and hippocampus. Open field and Morris water maze (MWM) tests were used to detect hippocampus-dependent cognitive function. Western blot and flow cytometry were conducted to detect neuronal apoptosis in primary hippocampal neurons. In vivo, peripheral APN administration reversed surgery-induced reductions in serum APN expression and elevated levels of cerebral lactate, the ratio of lactate/pyruvate, TNF-α and IL-1β, thereby improving cognitive performance in MWM and Open Field tests. In vitro, APN at concentrations of 2 and 10 ng/ml dose-dependently reduced lipopolysaccharide-induced caspase 3 expression and p38 phosphorylation in neurons, inhibiting apoptosis. Cerebral hypometabolism is one of the pathogenic mechanisms of PND. APN shows its effects on regulating glucose metabolism to inhibit neuroinflammation and neuronal apoptosis in PND. And the underlying mechanism of APN should be investigated further.

Adipokines and Adipose Tissue: The Role and Use of Sodium-Glucose Co-Transporter-2 (SGLT-2) Inhibitors in Patients with Diabetes or Heart Failure

Sodium-glucose co-transporter-2 (SGLT-2) inhibitors have become integral in treating both diabetes mellitus and heart failure, independent of left ventricular ejection fraction. Their pleiotropic effect influences multiple mechanisms, enhancing the function of various systems within the body. They exhibit nephroprotective and cardioprotective effects by improving cell metabolism, endothelial function, and slowing the fibrosis of the cardiac muscle, and they also have a beneficial impact on other organs. At the cellular level, they protect against the harmful effects of free radicals both by lowering glucose levels and by supporting the function of the antioxidant system. Moreover, SGLT-2 inhibitors can modify the metabolism of adipocytes by affecting the production of cytokines such as adiponectin-which increases insulin sensitivity, leading to weight loss and improved glycemic control.

Obesity: pathophysiology and therapeutic interventions

Over the past few decades, obesity has transitioned from a localized health concern to a pressing global public health crisis affecting over 650 million adults globally, as documented by WHO epidemiological surveys. As a chronic metabolic disorder characterized by pathological adipose tissue expansion, chronic inflammation, and neuroendocrine dysregulation that disrupts systemic homeostasis and impairs physiological functions, obesity is rarely an isolated condition; rather, it is frequently complicated by severe comorbidities that collectively elevate mortality risks. Despite advances in nutritional science and public health initiatives, sustained weight management success rates and prevention in obesity remain limited, underscoring its recognition as a multifactorial disease influenced by genetic, environmental, and behavioral determinants. Notably, the escalating prevalence of obesity and its earlier onset in younger populations have intensified the urgency to develop novel therapeutic agents that simultaneously ensure efficacy and safety. This review aims to elucidate the pathophysiological mechanisms underlying obesity, analyze its major complications-including type 2 diabetes mellitus (T2DM), cardiovascular diseases (CVD), non-alcoholic fatty liver disease (NAFLD), obesity-related respiratory disorders, obesity-related nephropathy (ORN), musculoskeletal impairments, malignancies, and psychological comorbidities-and critically evaluate current anti-obesity strategies. Particular emphasis is placed on emerging pharmacological interventions, exemplified by plant-derived natural compounds such as berberine (BBR), with a focus on their molecular mechanisms, clinical efficacy, and therapeutic advantages. By integrating mechanistic insights with clinical evidence, this review seeks to provide innovative perspectives for developing safe, accessible, and effective obesity treatments.

Obesity- and High-Fat-Diet-Induced Neuroinflammation: Implications for Autonomic Nervous System Dysfunction and Endothelial Disorders

Obesity is a multifactorial condition linked to severe health complications, including cardiovascular diseases and endothelial dysfunction. Both obesity and high-fat diets (HFDs) are strongly associated with neuroinflammation, particularly in the hypothalamus. The autonomic nervous system (ANS), which controls involuntary physiological processes, is critical for maintaining cardiovascular health, and its dysfunction is implicated in endothelial disorders. With its homeostatic control centers located in the hypothalamus and brainstem, a crucial question arises: could obesity- and HFD-induced neuroinflammation disrupt central ANS structures, leading to ANS dysfunction and subsequent endothelial disorders? This review examined whether neuroinflammation caused by obesity and HFD contributes to endothelial dysfunction through the dysregulation of the ANS. Our analysis revealed that hypothalamic inflammation linked to obesity and an HFD is associated with sympathetic hyperactivity and endothelial disorders. Identified molecular mechanisms include the influence of inflammatory cytokines, activation of the NF-κB/IKK-β pathway, microglial activation mediated by angiotensin II, circulating mitochondria triggering cGAS activation, and the stimulation of the TLR4 pathway. Our findings suggest that hypothalamic inflammation may play a central role in the interplay between obesity/an HFD, ANS dysfunction, and endothelial disorders.

Association Between Visceral Adipose Tissue and Chronic Respiratory Diseases: A Two-Sample Multivariable Mendelian Randomization Study in European Population

Background

The relationship between obesity and some respiratory diseases has been well documented. However there have been few studies on the association between visceral adipose tissue (VAT) and chronic respiratory diseases (CRDs), it remains unclear whether VAT is causally associated with CRDs.

Methods

We used two-sample Mendelian randomization (MR) to illuminate the effects of VAT on four CRDs: chronic obstructive pulmonary disease (COPD), allergic asthma, interstitial lung disease (ILD), and sarcoidosis. Inverse variance weighted (IVW) served as the primary assessment method. MR Egger, weighted median, Simple mode and Weighted mode were the supplementary methods for MR analysis. We used multivariate MR analysis to adjust for the effect of body mass index (BMI) on outcomes, Egger intercept, MR-pleiotropy residual sum and outlier, and leave-one-out analysis to confirm the MR results' consistency.

Results

Genetically-predicted VAT was associated with an increased risk of COPD (OR = 1.56; 95% CI: 1.34-1.82; P = 1.16×10-8), allergic asthma (OR = 1.44; 95% CI: 1.20-1.73; P = 8.63×10-5), and ILD (OR = 1.15; 95% CI: 1.04-1.26; P = 4.62×10-3). However, there was limited evidence to support an association between VAT and sarcoidosis. In multivariate MR analysis, VAT's associations with COPD, allergic asthma, and ILD persisted after adjusting for BMI.

Conclusion

This study provides evidence for a potential causal relationship between VAT and COPD, allergic asthma, and ILD; these relationships were independent of the effect of BMI.

Plasma adiponectin and biomarker-confirmed Alzheimer's disease in a tertiary memory clinic

Alzheimer's disease (AD) is associated with early metabolic dysfunction and adiponectin, which may play a pathophysiological role. Adiponectin is implicated in the regulation of energy homeostasis, carbohydrate, and lipid metabolism, as well as in inflammation modulation. The aim of this study was to study whether plasma adiponectin levels were different between patients with AD confirmed by biomarkers and neurological control subjects. We performed a monocentric, retrospective, cross-sectional, observational study in AD patients and neurological controls recruited from daily clinical practice in a tertiary memory clinic. Plasma adiponectin levels were measured using a chemiluminescent enzyme immunoassay. We analyzed the relationship between adiponectin and AD using linear regression models including age, gender, and BMI. We also described the distribution of adiponectin concentrations, across age, and gender categories. Two hundred and six patients (142 AD patients and 64 neurological controls) were included, with mean age = 68.8 ± 10.0 years, and 56% were women. Higher adiponectin concentrations were observed in females and in older adults. Plasma adiponectin levels were significantly higher in AD patients (mean = 6.45 ± 3.42 μg/mL) than neurological controls (4.85 ± 3.54 μg/mL) (p < .001). This association was mediated by age, gender, and BMI, which were significantly and independently associated with plasma adiponectin levels (p < .01 for each), while adiponectin was no longer associated with AD in multivariate models. Patients with AD showed higher adiponectin levels, but this association was driven by older age, female gender, and lower BMI in the AD group. Further studies are needed to better characterize the hormonal signature of AD.

Adiponectin mediated metabolic and sphingolipid alterations in preventing endothelial dysfunction

Endothelial dysfunction is an early indicator of atherosclerosis. Adiponectin, a hormone secreted by adipose tissue with insulin-sensitizing and anti-inflammatory properties, offers protection against atherosclerosis. This study investigated the metabolic and sphingolipid alterations in endothelial cells linked to the protective effects of adiponectin against endothelial dysfunction. Human Umbilical Endothelial Cells (HUVECs) were treated with Tumor Necrosis Factor-alpha (TNF-α) to induce endothelial dysfunction. AdipoRon and SKI-I were used to study the effects of adiponectin and sphingosine kinase inhibition in HUVECs. Metabolic changes and sphingolipid alterations were assessed to understand changes in lipid metabolism, and RNA sequencing was used to quantify the transcriptomics changes. TNF-α treatment significantly upregulated glycolysis and downregulated long-chain fatty acid oxidation and mitochondrial ATP production, while AdipoRon co-treatment partially reversed these metabolic effects. In HUVECs, TNF-α treatment increased intracellular C16 and C18 ceramides and Sphingosine 1-Phosphate (S1P) while decreasing extracellular S1P. AdipoRon Co-treatment reversed these effects; AdipoRon also reversed the transcriptional changes induced by TNF-α. Sphingosine kinase inhibition in HUVECs led to mitochondrial dysfunction at the metabolic and transcriptional levels. This study provides insights into potential therapeutic strategies targeting endothelial metabolism while unraveling a novel mitochondrial modulation mediated by sphingosine kinases in endothelial cells.

Effect of obesity on the acute response to SARS-CoV-2 infection and development of post-acute sequelae of COVID-19 (PASC) in nonhuman primates

Long-term adverse consequences of SARS-CoV-2 infection, termed "long COVID" or post-acute sequelae of COVID (PASC), are a major component of overall COVID-19 disease burden. Prior obesity and metabolic disease increase the severity of acute disease, but SARS-CoV-2 infection also contributes to the development of new-onset metabolic disease. Since the COVID pandemic occurred in the context of the global obesity epidemic, an important question is the extent to which pre-existing obesity modifies long-term responses to SARS-CoV-2 infection. We utilized a nonhuman primate model to compare the effects of infection with the SARS-CoV-2 delta variant in lean and obese/insulin-resistant adult male rhesus macaques over a 6-month time course. While some longitudinal responses to SARS-CoV-2 infection, including overall viral dynamics, SARS-CoV-2-specific IgG induction, cytokine profiles, and tissue persistence of viral RNA, did not appreciably differ between lean and obese animals, other responses, including neutralizing Ab dynamics, lung pathology, body weight, degree of insulin sensitivity, adipocytokine profiles, body temperature, and nighttime activity levels were significantly different in lean versus obese animals. Furthermore, several parameters in lean animals were altered following SARS-CoV-2 infection to resemble those in obese animals. Notably, persistent changes in multiple parameters were present in most animals, suggesting that PASC may be more prevalent than estimated from self-reported symptoms in human studies.

Distinguishing exocrine pancreas disease-associated diabetes from type 2 diabetes based on anthropometric and metabolic parameters

BACKGROUND

Adult-onset diabetes is most often considered to be type 2 diabetes. However, other types of diabetes can develop in adults, including exocrine pancreas disease-associated diabetes, also called type 3c diabetes. Differential diagnosis between these types of diabetes still remains a diagnostic challenge.

AIM

To define anthropometric and laboratory markers that will allow for early diagnosis of pancreatic disease-associated diabetes.

METHODS

The study group included 44 patients with pancreatogenic diabetes (26 with pancreatic cancer and 18 with chronic pancreatitis), while the control group consisted of 35 patients with type 2 diabetes. We analyzed several parameters, including sex, age, body mass index (BMI), fasting plasma glucose, fasting C-peptide and insulin with homeostasis model assessment of insulin resistance (HOMA-IR) index calculation, adrenomedullin, adiponectin and creatinine levels with epidermal growth factor receptor (eGFR) calculation. We also developed an equation, termed type 3c diabetes index, which utilized BMI, fasting insulin and adrenomedullin levels, and eGFR to better identify patients with type 3c diabetes.

RESULTS

Compared to patients with type 2 diabetes, patients with pancreatogenic diabetes had significantly lower BMI (25.11 ± 4.87 kg/m2 vs 30.83 ± 5.21 kg/m2), fasting C-peptide (0.81 ± 0.42 nmol/L vs 1.71 ± 0.80 nmol/L), insulin (76.81 ± 63.34 pmol/L vs 233.19 ± 164.51 pmol/L) and HOMA-IR index, despite similar fasting plasma glucose levels. Patients with pancreatogenic diabetes also had lower adrenomedullin levels (0.41 ± 0.25 ng/mL vs 0.63 ± 0.38 ng/mL) but higher adiponectin levels (13.08 ± 7.20 μg/mL vs 8.28 ± 4.01 μg/mL) and eGFR levels (100.53 ± 21.60 mL/min/1.73 m2 vs 85.14 ± 19.24 mL/min/1.73 m2). Finally, patients with pancreatogenic diabetes had significantly lower Type 3c diabetes index values.

CONCLUSION

Patients with pancreatogenic diabetes differ from patients with type 2 diabetes in anthropometric and laboratory parameters. The type 3c diabetes index had the highest discriminating value, above any single parameter.

Association of inflammatory markers and multimorbidity in young adults: cross-sectional findings from the Pelotas (Brazil) birth cohort, 1993

Early diagnosis can be a beneficial factor for minimizing health risks related to multimorbidity. This study aims to assess the association of multimorbidity with interleukin 6 (IL-6), C-reactive protein (CRP), and adiponectin in 22-year-old participants of the Pelotas (Brazil) birth cohort. A total of 3,578 subjects had serum measurements of IL-6, CRP, and adiponectin at the 22-year-old visit. For multimorbidity evaluation, a list of 15 morbidities was used and divided into subgroups (cardiometabolic, pulmonary, allergic diseases, and mental disorders). The occurrence of ≥ 2 morbidities was higher in females (55.1%) than in males (45.2%). A negative association between multimorbidity and adiponectin was found in females, whereas positive associations between the number of diseases and IL-6 and CRP were observed in males. For both sexes, cardiometabolic problem was the morbidity most associated with the markers. The analysis for isolated diseases identified dyslipidemia was the only cardiometabolic condition associated with physiological markers. Our findings suggest an inverse association between multimorbidity and adiponectin in females, as well as a direct cumulative association between the number of diseases and IL-6 and CRP in males at a young age.

Exploring CTRP6: a biomarker and therapeutic target in metabolic diseases

The rising prevalence of metabolic diseases is a significant global health concern. Beyond lifestyle management, targeting key molecules involved in metabolic regulation is essential. C1q/TNF-related protein 6 (CTRP6) is notably associated with glucose and lipid metabolism, with numerous studies highlighting its regulatory functions in metabolic diseases. This review summarizes the current knowledge on CTRP6, focusing on its gene expression profiles, protein structure, gene regulation, and role in metabolic diseases. CTRP6 is widely expressed across various tissues and features four distinct domains, with the C1q domain predicted to bind to its receptor. Notably, serum levels of CTRP6 are significantly elevated in patients with obesity and type 2 diabetes. In these conditions, adipose tissue serves as a key source of CTRP6 and its involvement in adipose tissue expansion, inflammation, and nutrient sensing has been observed in several studies. CTRP6 is also implicated in type 1 diabetes, gestational diabetes mellitus, and diabetic complications, particularly diabetic nephropathy. Although some studies have suggested that CTRP6 has protective roles in atherosclerotic cell models, myocardial infarction rat models, and ischemia/reperfusion injury mouse models, methodological issues such as unreliable antibodies and unstrict controls make it difficult to draw accurate conclusions from these studies. Patients with polycystic ovary syndrome (PCOS) exhibit elevated serum levels of CTRP6, although its direct impact on PCOS phenotypes remains unclear. In conclusion, CTRP6 emerges as a promising therapeutic target for metabolic diseases. A deeper understanding of CTRP6 will empower the scientific community to develop effective interventions to address the increasing prevalence of these diseases.

Effects of various exercise types on inflammatory response in individuals with overweight and obesity: a systematic review and network meta-analysis of randomized controlled trials

OBJECTIVE

To explore effective exercise types for reducing chronic inflammation in individuals with overweight and obesity (IOO) while accounting for confounders.

METHODS

A systematic search for RCTs in English between January 2000 and August 2023 was conducted to evaluating exercise effects on inflammatory biomarkers in IOO. A network meta-analysis conducted.

RESULTS

A total of 123 RCTs were analyzed. Different exercise type yielded distinct effects on various inflammatory biomarkers. Specifically, aerobic exercise combined with resistance training (COM) and aerobic exercise (AE) were the most effective for improving leptin levels. AE exhibited the greatest effectiveness in reducing CRP and increasing adiponectin. High-intensity interval training (HIIT) was identified as the most effective exercise modality for ameliorating IL-6, TNF-α, and IL-10. Resistance training (RT) had the least effect compared to other exercise types. Meta regression and subgroup analyses revealed that high-intensity AE demonstrated a greater effect size compared to moderate-intensity AE. The impact of AE on IL-10 was positively associated with both the training period and the age of participants. Positive correlations were observed between reductions in body fat and the effect sizes of CRP, TNF-α, and IL-10. Gender influenced AE effects on IL-6 and TNF-α, with females responding better.

CONCLUSION

This study highlights the potential of exercise in alleviating the inflammatory status in IOO, with different exercise types showing various effects on specific inflammatory biomarkers. The intensity and duration of exercise had a dose-response relationship with intervention effectiveness. Changes in body composition correlated with the effectiveness of the intervention. COM, AE, and HIIT are recommended exercise approaches.

Hypoxia signaling in the adipose tissue

Obesity per se is rapidly emerging all over the planet and further accounts for many other life-threatening conditions, such as diabetes, cardiovascular diseases, and cancers. Decreased oxygen supply or increased relative oxygen consumption in the adipose tissue results in adipose tissue hypoxia, which is a hallmark of obesity. This review aims to provide an up-to-date overview of the hypoxia signaling in the adipose tissue. First, we summarize literature evidence to demonstrate that hypoxia is regularly observed during adipose tissue remodeling in humans and rodent models with obesity. Next, we discuss how hypoxia-inducible factors (HIFs) are regulated and how adipose tissues behave in response to hypoxia. Then, the differential roles of adipose HIF-1α and HIF-2α in adipose tissue biology and obesity pathology are highlighted. Finally, the review emphasizes the importance of modulating adipose hypoxia as a therapeutic avenue to assist adipose tissues in functionally adapting to hypoxic conditions, ultimately promoting adipose health and improving outcomes due to obesity.

Adiponectin as a potential mediator of the pro-cognitive effects of physical exercise on Alzheimer's disease

ABSTRACT

Alzheimer's disease is the primary cause of dementia and imposes a significant socioeconomic burden globally. Physical exercise, as an effective strategy for improving general health, has been largely reported for its effectiveness in slowing neurodegeneration and increasing brain functional plasticity, particularly in aging brains. However, the underlying mechanisms of exercise in cognitive aging remain largely unclear. Adiponectin, a cell-secreted protein hormone, has recently been found to regulate synaptic plasticity and mediate the antidepressant effects of physical exercise. Studies on the neuroprotective effects of adiponectin have revealed potential innovative treatments for Alzheimer's disease. Here, we reviewed the functions of adiponectin and its receptor in the brains of human and animal models of cognitive impairment. We summarized the role of adiponectin in Alzheimer's disease, focusing on its impact on energy metabolism, insulin resistance, and inflammation. We also discuss how exercise increases adiponectin secretion and its potential benefits for learning and memory. Finally, we highlight the latest research on chemical compounds that mimic exercise- enhanced secretion of adiponectin and its receptor in Alzheimer's disease.

Adiponectin and Glucocorticoids Modulate Risk for Preterm Birth: The Healthy Start Study

CONTEXT

Adiponectin is a potent uterine tocolytic that decreases with gestational age, suggesting it could be a maternal metabolic quiescence factor. Maternal stress can influence preterm birth risk, and adiponectin levels may be stress responsive.

OBJECTIVE

We characterized associations between adiponectin and glucocorticoids with preterm birth and modeled their predictive utility. We hypothesized maternal plasma adiponectin and cortisol are inversely related and lower adiponectin and higher cortisol associate with preterm birth.

METHODS

We performed a nested case-control study using biobanked fasting maternal plasma. We included low-risk singleton pregnancies, and matched 1:3 (16 preterm, 46 term). We quantified high molecular weight (HMW), low molecular weight (LMW), and total adiponectin using an enzyme-linked immunosorbent assay. We validated a high-performance liquid chromatography-tandem mass spectrometry serum assay for use in plasma, to simultaneously measure cortisol, cortisone, and 5 related steroid hormones. We used linear/logistic regression to compare group means and machine learning for predictive modeling.

RESULTS

The preterm group had lower mean LMW adiponectin (3.07 μg/mL vs 3.81 μg/mL at 15 weeks (w) 0 days (d), P = .045) and higher mean cortisone (34.4 ng/mL vs 29.0 ng/mL at 15w0d, P = .031). The preterm group had lower cortisol to cortisone and lower LMW adiponectin to cortisol ratios. We found HMW adiponectin, cortisol to cortisone ratio, cortisone, maternal height, age, and prepregnancy body mass index most strongly predicted preterm birth (area under the receiver operator curve = 0.8167). In secondary analyses, we assessed biomarker associations with maternal self-reported psychosocial stress. Lower perceived stress was associated with a steeper change in cortisone in the term group.

CONCLUSION

Overall, metabolic and stress biomarkers are associated with preterm birth in this healthy cohort. We identify a possible mechanistic link between maternal stress and metabolism for pregnancy maintenance.

The effects of regular exercise on cognitive and cardiometabolic health in testicular cancer survivors subjected to platinum-based chemotherapy

BACKGROUND

Platinum-based chemotherapy provides curative treatment to more than 95% of patients with testicular germ cell tumor but it has negative cardiometabolic and neurological effects. Regular exercise can alleviate late chemotherapy-related toxicities. We examined the impact of a 6-month supervised aerobic-strength training on cognitive and cardiometabolic health and residual level of platinum in cancer survivors.

METHODS

Twenty-eight middle-aged (42.1 ± 7.6 years) testicular germ cell tumor survivors subjected to platinum-based chemotherapy (1-8 cycles, 0-24 years ago) were recruited into exercise (n = 20) and control (n = 8) groups. Effects of 6-month exercise training on the whole-body and muscle metabolism, cognitive functions, cardiopulmonary fitness, residual plasma platinum, and plasma adiponectin were examined.

RESULTS

Exercise intervention improved cardiopulmonary fitness and cognitive functions, reduced residual plasma platinum, visceral adiposity and muscle lipids, improved glucose (glycosylated hemoglobin) and lipid (high-density lipoprotein cholesterol) metabolism, and enhanced dynamics of muscle post-exercise phosphocreatine recovery. Exercise-related decline in plasma platinum was paralleled by decline of muscle glycerophosphocholines and by the enhanced metabolic flexibility during low-intensity exercise, and predicted training-induced increase in cognitive functions.

CONCLUSIONS

The 6-month exercise intervention resulted in improved cognitive and cardiometabolic health in testicular germ cell tumor survivors, which was paralleled by reduced plasma platinum, providing evidence that structured supervised exercise brings multiple health benefits to testicular germ cell tumor survivors.

Reversal of neuronal tau pathology via adiponectin receptor activation

Changes in brain mitochondrial metabolism are coincident with functional decline; however, direct links between the two have not been established. Here, we show that mitochondrial targeting via the adiponectin receptor activator AdipoRon (AR) clears neurofibrillary tangles (NFTs) and rescues neuronal tauopathy-associated defects. AR reduced levels of phospho-tau and lowered NFT burden by a mechanism involving the energy-sensing kinase AMPK and the growth-sensing kinase GSK3b. The transcriptional response to AR included broad metabolic and functional pathways. Induction of lysosomal pathways involved activation of LC3 and p62, and restoration of neuronal outgrowth required the stress-responsive kinase JNK. Negative consequences of NFTs on mitochondrial activity, ATP production, and lipid stores were corrected. Defects in electrophysiological measures (e.g., resting potential, resistance, spiking profiles) were also corrected. These findings reveal a network linking mitochondrial function, cellular maintenance processes, and electrical aspects of neuronal function that can be targeted via adiponectin receptor activation.

Exploring the Logic and Conducting a Comprehensive Evaluation of the Adiponectin Receptor Agonists AdipoRon and AdipoAI's Impacts on Bone Metabolism and Repair-A Systematic Review

INTRODUCTION

Adiponectin replacement therapy shows promising outcomes in various diseases, especially for bone-related disorders. Challenges in using the complete protein have led to alternative approaches, with AdipoRon and AdipoAI emerging as extensively researched drug candidates. Their influence on models of bone-related disorders has progressed considerably but there has been no review of their effectiveness in modulating bone metabolism and repair.

METHODS

This systematic review seeks to address this knowledge gap. Based on preclinical evidence from PubMed, EMBASE, and COCHRANE, ten studies were included following PRISMA guidelines. The JBI Checklist Critical Appraisal Tool assessed the quality of this systematic review. The studies encompassed various animal models, addressing bone defects, osseointegration, diabetes-associated periodontitis, fracture repair, growth retardation, and diabetes-associated peri-implantitis.

RESULTS

AdipoRon and AdipoAI demonstrated effectiveness in modulating bone metabolism and repair through diverse pathways, including the activation of AdipoR1/APPL1, inhibition of F-actin ring formation, suppression of IκB-α phosphorylation, p65 nuclear translocation and Wnt5a-Ror2 signaling pathway, reduction of CCL2 secretion and expression, regulation of autophagy via LC3A/B expression, modulation of SDF-1 production, activation of the ERK1/2 signaling pathway, modulation of bone integration-related markers and osteokines such as RANKL, BMP-2, OPG, OPN, and Runx2, inhibition of RANKL in osteoblasts, and inhibition of podosome formation via the activation of AMPK.

CONCLUSION

While preclinical studies show promise, human trials are crucial to confirm the clinical safety and effectiveness of AdipoRon and AdipoAI. Caution is necessary due to potential off-target effects, especially in bone therapy with multi-target approaches. Structural biology and computational methods can help predict and understand these effects.

Effects of duration of high-fat diet on adipocyte hyperplasia in rat epididymis

BACKGROUND

High-fat diet (HFD) contributes to obesity and enhances the expression of mature adipocyte markers. However, the effect of HFD on adipocyte hyperplasia remains controversial. This may be due to variations in the duration of HFD. This study aimed to investigate the effects of different durations of HFD on adipocyte hyperplasia and the expression of mature adipocyte-related markers in obese rats.

METHODS

We divided 32 Sprague-Dawley rats into four groups: B (standard diet control), H1 (HFD for four weeks), H2 (HFD for eight weeks), and H3 (HFD for 12 weeks). We evaluated the morphological changes in epididymal fat cells, measured serum inflammatory markers using enzyme-linked immunosorbent assay (ELISA) kits, and quantified adipocyte hyperplasia and maturation markers using western blotting.

RESULTS

We observed progressive increases in body weight, epididymal fat weight, serum leptin, TNF-α, IL-6, irisin, PPARγ, adiponectin, and FNDC5 protein expression over 8 weeks of HFD. 12 weeks of HFD intervention resulted in significant decreases in irisin, PPARγ, adiponectin, and FNDC5. Concurrently, the expression of perilipin A and ATGL declined with prolonged HFD.

CONCLUSIONS

Our results suggest that the duration of HFD significantly affects adipocyte ability to undergo hyperplasia in the epididymis of obese rats. Specifically, 4 weeks of HFD did not change the capacity for adipocyte hyperplasia, while 8 weeks of the diet enhanced this capacity. Interestingly, a longer diet duration (12 weeks) led to a decrease in adipocyte hyperplasia.

Strength Training can Modulate Urinary Adipokine Levels in Healthy Young Males

Adipose tissue stores energy in fat-rich adipocytes, which can produce and release several adipokines and modulate body metabolism. Exercise may induce adipokine production in adipocytes; however, the relationship between the two remains unclear. Few studies have shown the relationship between adipokines and strength training. Thus, we aimed to evaluate the acute and chronic effects of strength training (ST) on urinary adiponectin, leptin, and resistin levels. Twelve untrained young men (23.42 ± 2.67 years) were included in this study. Body composition was evaluated at baseline and after completing of the training protocol using densitometry. Training protocol consisted of three exercises with three sets of 65% of one-repetition maximum (1MR) with a pause of 90 s between sets, each exercise lasting 5 s (2 s concentric / 3 s eccentric). The sessions were carried out three times a week for 10 weeks. Urine was collected during the pre- and post-training in the first and 30th session. Adipokine levels were determined by ELISA. Urinary levels of leptin acutely increased after the first ST session, and after the last ST session. Chronic changes in the leptin levels were also found when comparing the values before the last ST and before the first ST session. Urinary adiponectin levels changed in the comparison of values before and after the last session. There was a significant increase in the adiponectin levels when comparing values after the first and last ST sessions. The levels of resistin chronically increased. Strength training can induce acute and chronic changes in urinary levels of adipokines.

Neonatal body composition, salivary feeding gene expression, and feeding outcomes in infants of diabetic mothers

Introduction

Infants of diabetic mothers (IDMs) may exhibit decreased oral intake, requiring nasogastric feedings and prolonged hospitalization. The objective of this study was to explore whether saliva serves as an informative biofluid for detecting expression of hunger signaling and energy homeostasis modulator genes and to perform exploratory analyses examining expression profiles, body composition, and feeding outcomes in late preterm and term IDMs and infants born to mothers with normoglycemia during pregnancy.

Methods

In this prospective cohort pilot study, infants born at ≥ 35 weeks' gestation to mothers with gestational or type II diabetes (IDM cohort) and normoglycemic mothers (control cohort) were recruited. The presence of known hunger signaling genes: 5'AMP-activated protein kinase (PRKAA2) and neuropeptide Y2 receptor (NPY2R); adipokines: leptin (LEP) and adiponectin (ADIPOQ); and energy homeostasis regulators: ghrelin (GHRL) and proopiomelanocortin (POMC) in neonatal saliva was determined with RT-qPCR and compared between cohorts. Body composition was assessed via skinfold measurements and compared between cohorts. Feeding outcomes were recorded. Exploratory analyses were performed examining associations between infant body composition, energy homeostasis and hunger signaling gene expression.

Results

Twenty-three infants in the IDM cohort and 22 infants in the control cohort were recruited. LEP and ADIPOQ were not reliably detected in neonatal saliva in either cohort. PRKAA2, GHRL and NPY2R were less likely to be detected in the IDM cohort, whereas POMC was more likely to be detected in the IDM cohort. Infants in the IDM cohort had greater adiposity compared to infants in the normoglycemia cohort. Only 3 IDMs had documented poor feeding; no infant in the control group struggled to feed. In exploring associations between hunger signaling gene expression with energy homeostasis gene expression and body composition, the odds of detecting salivary NPY2R expression decreased as fat mass increased, and the odds of detecting PRKAA2 expression increased in the presence of GHRL expression.

Discussion

Non-invasive assessment of hunger signaling and energy homeostasis gene expression is possible through neonatal salivary analysis. This pilot study lays the foundation for a larger scale study to further investigate the link between in utero exposure to diabetes with body composition and regulation of appetite.

Novel secreted regulators of glucose and lipid metabolism in the development of metabolic diseases

The tight regulation of glucose and lipid metabolism is crucial for maintaining metabolic health. Dysregulation of these processes can lead to the development of metabolic diseases. Secreted factors, or hormones, play an essential role in the regulation of glucose and lipid metabolism, thus also playing an important role in the development of metabolic diseases such as type 2 diabetes and obesity. Given the important roles of secreted factors, there has been significant interest in identifying new secreted factors and new functions for existing secreted factors that control glucose and lipid metabolism. In this review, we evaluate novel secreted factors or novel functions of existing factors that regulate glucose and lipid metabolism discovered in the last decade, including secreted isoform of endoplasmic reticulum membrane complex subunit 10, vimentin, cartilage intermediate layer protein 2, isthmin-1, lipocalin-2, neuregulin-1 and neuregulin-4. We discuss their discovery, tissues of origin, mechanisms of action and sex differences, emphasising their potential to regulate metabolic processes central to diabetes. Additionally, we discuss the translational barriers, particularly the absence of identified receptors, that hamper their functional characterisation and further therapeutic development. Ultimately, the identification of new secreted factors may give insights into previously unidentified pathways of disease progression and mechanisms of glucose and lipid homeostasis.

Pathological mechanisms and related markers of steroid-induced osteonecrosis of the femoral head

BACKGROUND

Osteonecrosis of the femoral head (ONFH) is a refractory orthopedic disease with a high disability rate. Long-term administration of steroids is the most common pathogenic factor for non-traumatic ONFH. Early diagnosis of steroid-induced osteonecrosis of the femoral head (SONFH) is difficult and mainly depends on imaging.

OBJECTIVES

The objectives of this review were to examine the pathological mechanisms of SONFH, summarize related markers of SONFH, and identify areas for future studies.

METHODS

We reviewed studies on pathological mechanisms and related markers of SONFH and discussed the relationship between them, as well as clinical applications and the outlook of potential markers.

RESULTS

The pathological mechanisms of SONFH included decreased osteogenesis, lipid accumulation, increased intraosseous pressure, and microcirculation disruption. Differential proteomics and genomics play crucial roles in the occurrence, progression, and outcome of SONFH, providing novel insights into SONFH. Additionally, the biological functions of mesenchymal stem cells (MSCs) and exosomes (Exos) in SONFH have attracted increasing attention.

CONCLUSIONS

The pathological mechanisms of SONFH are complex. The related markers mentioned in the current review can predict the occurrence and progression of SONFH, which will help provide effective early clinical prevention and treatment strategies for SONFH.

Development of a non-invasive bioassay for adiponectin target engagement in mice

Adiponectin-based therapeutic strategies are promising for managing metabolic diseases and reducing inflammation, prompting the development of adiponectin receptor agonists. However, monitoring their pharmacodynamic actions in clinical applications is challenging. This study aimed to identify peripheral biomarkers to monitor adiponectin actions using ALY688, an adiponectin receptor agonist peptide. RNA sequencing analysis of whole blood identified a cluster of genes that were significantly increased in the ALY688-treated group compared to the control. This gene cluster was validated by qPCR and further confirmed in human peripheral blood mononuclear cells treated with ALY688 ex vivo. We also confirmed a functional outcome of ALY688 action in mice as our study also demonstrated the anti-inflammatory effect of ALY688 in a sublethal LPS mouse model. In summary, a newly identified gene cluster signature is suitable for assessing the pharmacodynamic action of adiponectin or its mimetics in blood samples.

Protective activity of hirsutidin in high-fat intake and streptozotocin-induced diabetic rats: In silico and in vivo study

Background

Type 2 diabetes mellitus (T2DM) is defined by a wide variety of metabolic abnormalities, persistent hyperglycemia, and a slew of other complications. Catharanthus roseus L. (apocyanaceae), remarkably notable as Vinca Rosea, appears to be the source of the active component hirsutidin, which is reported in various diseases.

Objective

The study intended to appraise the antidiabetic capability of hirsutidin in a high-fat diet (HFD) and streptozotocin (STZ) induced diabetes in experimental rats.

Materials and methods

An experimental rodent T2DM model was elicited by consuming an HFD regimen with STZ 50 mg/kg, i.p. dose formulated in a 0.1 M cold citrate buffer (pH 4.5). The test drug hirsutidin (10 and 20 mg/kg) and the standard drug glimeclamide (5 mg/kg) were administered daily for six weeks. The efficacy of hirsutidin was observed on several diabetes parameters. The average body weight and an array of biochemical markers were determined, including blood glucose, insulin, dyslipidemia (lipid profile), total protein (TP), liver injury [aspartate aminotransferase (AST), alanine aminotransferase (ALT)], inflammation [IL-6, IL-1β, tumor necrosis factor-α (TNF-α)], oxidative stress [malondialdehyde (MDA)] and antioxidant status [catalase (CAT), glutathione (GSH), and superoxide dismutase (SOD)]. In addition, the concentrations of leptin, adiponectin, and resistin were also assessed. Also, molecular docking studies were undertaken to investigate critical targets associated with diabetes, including TNF-α, insulin, adiponectin, and leptin.

Results

Diabetes induction with HFD/STZ resulted in hyperglycemia (significantly reduced blood glucose and increased insulin level), dyslipidemia (significantly reduced TC, TG and increased HDL), total protein (significantly reduced), oxidative stress and antioxidant status (significantly reduced MDA and increased CAT, SOD and GSH levels), inflammation (significantly decreased IL-6, IL-1β, TNF-α), liver damage (significantly reduced AST, ALT), and specific hormones such as adiponectin, leptin significantly improved and resistin significantly reduced as evidenced by biochemical data in this study. Intermolecular interactions of ligands and docking score, hirsutidin proteins TNF-α (2AZ5), Insulin (4IBM), Adiponectin (6KS1), Leptin (7Z3Q) with binding energy of -6.708, -7.674, -7.2 and -7.547 Kcal/mol.

Conclusion

Hirsutidin may have an evidential hypoglycemic outcome and may exhibit potent antidiabetic activity in HFD/STZ-induced T2DM in rats. Treatment with hirsutidin significantly improved glycemic control, lipid metabolism, oxidative stress, inflammation, and liver function. Additionally, it normalized dysregulated levels of adiponectin, leptin, and resistin. Molecular docking confirmed its strong binding affinity to key diabetic targets.

Loss of adipose ATF3 promotes adipose tissue lipolysis and the development of MASH

The crosstalk between adipose tissue and the liver is finely controlled to maintain metabolic health. Yet, how adipose tissue controls toxic free fatty acid overflow into the liver remains incompletely understood. Here, we show that adipocyte activating transcription factor 3 (ATF3) was induced in human or mouse obesity. Adipocyte Atf3-/- (Atf3Adi-/-) mice developed obesity, glucose intolerance, and metabolic dysfunction-associated steatohepatitis (MASH) in chow diet, high-fat diet, or Western diet-fed mice. Blocking fatty acid flux by inhibiting hepatocyte CD36, but not the restoration of hepatic AMPK signaling, prevented the aggravation of MASH in Atf3Adi-/- mice. Further studies show that the loss of adipocyte ATF3 increased lipolysis via inducing adipose triglyceride lipase, which in turn induced lipogenesis and inflammation in hepatocytes. Moreover, Atf3Adi-/- mice had reduced energy expenditure and increased adipose lipogenesis and inflammation. Our data demonstrate that adipocyte ATF3 is a gatekeeper in counteracting MASH development under physiological and pathological conditions.

The Role of Adipokines between Genders in the Pathogenesis of Osteoarthritis

Osteoarthritis (OA) is a chronic, progressive, degenerative joint disease characterized by joint pain, stiffness, and limited movement. It presents significant intra- and inter-individual variability-in particular, between genders. Recent research has increasingly focused on the role of adipokines-especially leptin, adiponectin, and resistin-in the development of OA. Adipokines, peptide hormones primarily secreted by adipose tissue, are involved in crucial physiological processes related to metabolism and immunity. They can also impact bone and cartilage turnover by interacting with joint cells such as osteoblasts, osteoclasts, chondrocytes, and mesenchymal stem cells, thereby linking inflammation with bone cartilage homeostasis. This review aims to elucidate the structure and functions of various adipokines, their serum and synovial levels, and their association with clinical presentation and radiographic progression in OA patients, with a focus on differences between sexes. A narrative literature review was conducted using three databases specifically analyzing sex differences. OA patients generally show elevated serum and synovial levels of leptin, chemerin, and visfatin, as well as high plasma levels of resistin and visfatin. In contrast, synovial levels of adiponectin and omentin are reduced in OA patients compared to healthy individuals, with an inverse relationship to disease severity, suggesting a potential protective role. Resistin and leptin were positively correlated with pain severity and radiographic progression, while adiponectin's role in OA remains controversial. Regarding sex differences, male OA patients exhibited higher serum levels of leptin, chemerin, and omentin compared to healthy controls, with a positive correlation to the BMI and estrogen levels, potentially explaining the sexual dimorphism observed in this condition. Studies on visfatin and lipocalin did not reveal significant differences in synovial or serum levels between the sexes. The role of resistin remains controversial. Adipokines influence the joint microenvironment and contribute to the progression of osteoarthritis (OA). However, the precise biological mechanisms are not yet fully understood due to the complex interactions between the metabolic, mechanical, and immune systems. Further research is needed to clarify their roles in OA and to identify targeted therapies for managing this degenerative disease.

Association of ADIPOQ Single Nucleotide Polymorphisms (SNPs) with Obesity Risk in Different Populations: A Systematic Review and Analysis

Background

Thirty-two single nucleotide polymorphisms (SNPs) are commonly found in ADIPOQ. APN levels are decreased in obesity, and SNPs of the ADIPOQ gene affecting APN have varying associations with the development of obesity in different populations. This systematic review and meta-analysis aimed to investigate the association of SNPs in ADIPOQ with the risk of obesity development in various populations.

Methods

A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist date up to Feb 2023. We used the Newcastle-Ottawa scale to find out if a study fit the main criteria for submission and to assess the data quality of the articles included in the systematic review and meta-analysis. Odds ratios (OR) and 95% confidence intervals (CI) were calculated via Review Manager (RM) V.5.4 to estimate the connection between ADIPOQ polymorphic qualities of a gene and the risk of developing obesity.

Results

The present study analysed the association between ADIPOQ polymorphisms (rs1501299, rs2241766, rs266729, rs822393, and rs822396) and obesity risk and suggested that APN is partially responsible for the emergence of obesity and increases its risk.

Conclusion

It is important to take into account several limitations of this meta-analysis when evaluating the findings. First off, even though we looked through numerous databases for all relevant papers, there is a chance we overlooked some. Our capacity to arrive at more firm conclusions was further hampered by the small number of papers that made up our meta-analysis. The most current data, however, are presented in this study since it used newly published data to perform a meta-analysis and evaluate the relationship between ADIPOQ polymorphisms and obesity.

The impact of the obesity onset on the inflammatory and glycemic profile of women with severe obesity

BACKGROUND

The stage of life at the onset of obesity is an important factor in assessing inflammatory state and cardiometabolic risk.

OBJECTIVES

This study aimed to evaluate the relationship between the obesity onset and the inflammatory profile in women with severe obesity.

SETTING

Public hospital, Brazil.

METHODS

Forty-eight women with severe obesity (20-59 yr old) were evaluated according to weight, height, neck circumference (NC), waist circumference (WC), and hip circumference, as well blood metabolic and inflammatory parameters. The participants were grouped according to obesity onset stage of life (early group: ≤19 yr; late group: >19 yr).

RESULTS

The demographic means of the participants were: age of 39.7 years, weight of 122.7 kg and body mass index (BMI) of 48.4 kg/m2. The late group presented significantly higher values of leptin (lep)/adiponectin (adipo) ratio and homeostatic model assessment for insulin resistance (HOMA-IR) than the early group. The late group also had a lower adipo/lep ratio. Moreover, the late group showed correlations between the lep/adipo ratio and BMI (r = .460, P = .021), NC (r = .478, P = .016), and WC (r = .535, P = .006). Adipo was also correlated with NC (r = -.418, P = .038), WC (r = -.437, P = .029), and glycated hemoglobin (HbA1C) (r = -.485, P = .019). By contrast, in the early group, the lep/adipo ratio showed correlations with insulin (r = .647, P = .004) and HOMA-B (r = .564, P = .015).

CONCLUSIONS

The inflammatory profile is correlated with anthropometric values in women with late-onset obesity. Inflammatory markers seemed to correlate with the glycemic profile in women with early-onset obesity. Furthermore, inflammation was higher in women with late-onset obesity compared to those with early-onset obesity.

Reduced hepatic AdipoR2 by increased glucocorticoid mediates effect of psychosocial stress to elevate serum cholesterol

Understanding the effects of psychosocial stress on serum cholesterol may offer valuable insights into the relationship between psychological disorders and endocrine diseases. However, these effects and their underlying mechanisms have not been elucidated yet. Here we show that serum corticosterone, total cholesterol and low-density lipoprotein cholesterol (LDL-C) are elevated in a mouse model of psychosocial stress. Furthermore, alterations occur in AdipoR2-mediated AMPK and PPARα signaling pathways in liver, accompanied by a decrease in LDL-C clearance and an increase in cholesterol synthesis. These changes are further verified in wild-type and AdipoR2 overexpression HepG2 cells incubated with cortisol and AdipoR agonist, and are finally confirmed by treating wild-type and hepatic-specific AdipoR2 overexpression mice with corticosterone. We conclude that increased glucocorticoid mediates the effects of psychosocial stress to elevate serum cholesterol by inhibiting AdipoR2-mediated AMPK and PPARα signaling to decrease LDL-C clearance and increase cholesterol synthesis in liver.

Proteomics identifies hypothermia induced adiponectin protects corneal endothelial cells via AMPK mediated autophagy in phacoemulsification

AIM

To explore the molecular mechanism underlying the protective effect of hypothermic perfusion on the corneal endothelium during phacoemulsification.

METHODS

Phacoemulsification was performed on New Zealand white rabbits. Perfusate at different temperatures was used during the operation, and the aqueous humor was collected for proteomic sequencing after the operation. Corneal endothelial cell injury was simulated by a corneal endothelial cell oxygen-glucose deprivation/reoxygenation (OGD/R) model in vitro. Flow cytometry and evaluation of fluorescent LC3B puncta were used to detect apoptosis and autophagy, and western blotting was used to detect protein expression.

RESULTS

A total of 381 differentially expressed proteins were identified between the two groups. In vitro, 4 ℃ hypothermia significantly reduced apoptosis and promoted autophagy. Apoptosis increased after autophagy was inhibited by 3-Methyladenine (3-MA). Furthermore, adiponectin (ADIPOQ) knockdown inhibited phospho-AMPK and blocked the protective effect of hypothermia on corneal endothelial cells.

CONCLUSIONS

We investigated the differential expression of proteins between the hypothermia group and normothermia group by proteomics. Moreover, hypothermia-induced ADIPOQ can reduce apoptosis by promoting AMPK-mediated autophagy.

Uncovering the connection between obesity and thyroid cancer: the therapeutic potential of adiponectin receptor agonist in the AdipoR2-ULK axis

Adiponectin, a unique adipose-derived factor, is significantly downregulated in obesity, making it a crucial target for tumor-related metabolic research. AdipoRon is a novel adiponectin receptor agonist with the advantages of a small molecular weight, high stability and a long half-life. By screening the cervical adipose tissue of papillary thyroid carcinoma (PTC) patients with adipokine antibody array, we found that adiponectin was a potential correlation factor between obesity and PTC progression. AdipoRon has oral activity and is easily absorbed and delivered to target tissues. The effects of AdipoRon on thyroid cancer have not been reported. In this study, we identified adiponectin receptor 1 (AdipoR1) and AdipoR2 on the surface of thyroid cancer cell lines. AdipoRon inhibited the proliferation and migration of thyroid cancer cells, limited energy metabolism in thyroid cancer cells, promoted differentiation of thyroid cancer cells, and induced autophagy and apoptosis. Mechanistic studies revealed that AdipoRon inhibited p-mTOR Ser2448 and p-p70S6K Thr389, and activated ULK1 and p-ULK1. ULK1 knockdown suppressed the effect of AdipoRon on LC3BII/I protein and lysosomes. AdipoR2 knockdown reduced AdipoRon-induced autophagy in thyroid cancer cells. This study is the first to demonstrate the role of AdipoRon in PTC. Our findings illustrate a previously unknown function and mechanism of the AdipoRon-AdipoR2-ULK/p-ULK1 axis in PTC and lay the foundation for clinical translation of AdipoRon to PTC. Targeting the AdipoRon-AdipoR2-ULK/p-ULK1 axis may represent a new therapeutic strategy for PTC.

Serum Adiponectin Is Elevated in Critically Ill Patients with Liver Disease and Associated with Decreased Overall Survival

BACKGROUND

Adiponectin, an adipokine with anti-inflammatory properties, has been implicated in various liver diseases. This study aimed to elucidate the prognostic value of serum adiponectin levels in critically ill patients with liver disease.

METHODS

This observational study included 161 critically ill patients admitted to the medical ICU of RWTH Aachen University Hospital due to acute liver failure or decompensated advanced chronic liver disease. Serum adiponectin levels were measured at ICU admission and after 48 h. Clinical parameters and outcomes, including transplant-free survival, were analyzed.

RESULTS

Serum adiponectin concentrations were significantly elevated compared to healthy controls (p < 0.001). Levels were particularly high in patients with sepsis compared to those with gastrointestinal bleeding as the precipitating factor of acute decompensation (p = 0.045) and were higher in female patients (p = 0.023). Adiponectin concentrations correlated with the Model of End-Stage Liver Disease (MELD) score and Child-Pugh score. Multivariate analysis confirmed a significant correlation with total bilirubin (r = 0.292, p < 0.001) and serum sodium (r = -0.265, p = 0.028). Higher adiponectin concentrations were associated with a trend towards poorer 30- and 180-day survival. Cox regression analysis identified a significant association between increased adiponectin concentration and reduced transplant-free survival (p = 0.037), supported by a Kaplan-Meier analysis using a cutoff of 119 ng/mL (log-rank 5.145, p = 0.023).

CONCLUSIONS

Elevated serum adiponectin concentrations are associated with liver dysfunction and poor outcomes in critically ill patients. Higher adiponectin levels at ICU admission may predict poorer transplant-free survival. Further research in larger, multicenter cohorts is warranted to validate these findings and explore the underlying mechanisms.

Correlation between Overweight, Obesity, Gestational Diabetes Mellitus, Adipokines (Adipolin and Adiponectin), and Adverse Pregnancy Outcomes: A Pilot Study

Background: The prevalence of overweight (OW), obesity (OB), and gestational diabetes mellitus (GDM) has been increasing worldwide in recent years. Adipolin is a new adipokine with reduced circulating levels in obesity and type 2 diabetes mellitus (T2DM). Objectives: Our prospective case-control study aimed to evaluate the maternal serum levels of adipolin and adiponectin, metabolic parameters, and anthropometric characteristics at the time of oral glucose tolerance test (OGTT) in pregnant women with a pre-pregnancy body mass index (BMI) ≥ 25 Kg/m2 and correlate them with newborn adipolin, adiponectin levels, and anthropometric characteristics of the newborns, and secondly to evaluate pregnancy outcomes. Material and Methods: After the OGTT results, we had 44 OW/OB pregnant women with GDM, 30 OW/OB pregnant women without GDM, and 92 lean healthy (LH) pregnant women. Data were analyzed by ANOVA and correlation tests, with a p-value < 0.05 considered significant. Results: We found no differences between adipolin values of the OW/OB pregnant women with GDM and the LH group (p > 0.99), OW/OB without GDM and the LH group (p = 0.56), and between OW/OB groups (p = 0.57). OW/OB pregnant women with GDM had a higher rate of gestational hypertension compared with the LH group (p < 0.0001). Newborns from OW/OB pregnant women with GDM were more frequently diagnosed with jaundice (p = 0.02), and they required more frequent admission to the neonatal intensive care unit (NICU) for treatment of respiratory distress (p = 0.01) compared with newborns from LH mothers. Conclusions: Our study revealed that the serum levels of adipolin in the second trimester among the group of OW/OB pregnant women with GDM, matched for age and BMI with OW/OB pregnant women without GDM, were not significantly different. This suggests that adipolin may not play an essential role in the occurrence of GDM in these patients. Despite good glycemic control during pregnancy, OW/OB pregnant women with GDM and their newborns tend to have more complications (gestational hypertension, jaundice, NICU admission) than LH pregnant women and their newborns, highlighting the importance of weight control before pregnancy.

Predictors of weight and waist gain in US South Asians: Findings from the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study

Background

Weight and waist gain are significant concerns in adulthood. Both weight and waist gain are particularly important among South Asians, known to have an increased risk of developing chronic cardiometabolic complications at any body mass index compared to other racial and ethnic groups. The aim of this study was to investigate factors predicting weight and waist gain in a longitudinal cohort of South Asians living in the US (United States).

Methods

This was a prospective analysis using data from exam 1 (2010-2013) and exam 2 (2015-2018) of the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study, a prospective cohort study of South Asians (recruited from San Francisco and Chicago), with a mean 4.8 years of follow-up.

Results

Of 634 participants studied (42.7 % women, mean age 55 years, BMI 25.7 kg/m2, weight 70.4 kg at exam 1), 34.7 % had gained ≥5 % weight and 32.3 % gained ≥5 % waist at exam 2. In the adjusted models, older age, higher number of years of US residence, and having diabetes were associated with lower odds of weight gain; being female and having higher adiponectin were associated with higher odds of weight gain. Being female and being employed full/part time or being retired predicted lower likelihood of waist gain. Being single, separated/divorced, having a higher leptin and a higher C-reactive protein level predicted higher likelihood of waist gain.

Conclusions

The current study identified several social, demographic, and clinical factors that can serve as targets for obesity interventions among US South Asians. In addition, this study also raises hypotheses about associations of adipokine levels with weight and waist gain.

The Impact of the Endocrine and Immunological Function of Adipose Tissue on Reproduction in Women with Obesity

Obesity, which leads to metabolic dysregulation and body function impairment, emerges as one of the pressing health challenges worldwide. Excessive body fat deposits comprise a dynamic and biologically active organ possessing its own endocrine function. One of the mechanisms underlying the pathophysiology of obesity is low-grade systemic inflammation mediated by pro-inflammatory factors such as free fatty acids, lipopolysaccharides, adipokines (including leptin, resistin and visfatin) and cytokines (TNF-α, IL-1β, Il-6), which are secreted by adipose tissue. Together with obesity-induced insulin resistance and hyperandrogenism, the exacerbated immune response has a negative impact on the hypothalamic-pituitary-gonadal axis at all levels and directly affects reproduction. In women, it results in disrupted ovarian function, irregular menstrual cycles and anovulation, contributing to infertility. This review focuses on the abnormal intracellular communication, altered gene expression and signaling pathways activated in obesity, underscoring its multifactorial character and consequences at a molecular level. Extensive presentation of the complex interplay between adipokines, cytokines, immune cells and neurons may serve as a foundation for future studies in search of potential sites for more targeted treatment of reproductive disorders related to obesity.

Inspiratory Muscle Training in Patients Living With Chronic Kidney Disease and Receiving Hemodialysis: Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

People living with chronic kidney disease (CKD) and receiving hemodialysis (HD) have impaired respiratory muscle strength and endurance. The objective of this study was to systematically review the effects of inspiratory muscle training (IMT) on respiratory muscle strength, functional capacity, lung function, quality of life, endothelial function, and oxidative stress in people living with CKD and receiving HD.

METHODS

An electronic search was conducted from inception to June 2023. Randomized controlled trials that evaluated the effects of IMT on respiratory muscle strength, functional capacity, lung function, endothelial function, quality of life, or oxidative stress in adults living with CKD and receiving HD, compared with control, placebo IMT, or conventional physical therapy, were included.

RESULTS

Eight studies were included, totaling 246 people. The meta-analysis showed that IMT increased the maximum inspiratory pressure (MIP) by 22.53 cm H2O, the maximum expiratory pressure (MEP) by 19.54 cm H2O, and the distance covered in the 6-minute walk test by 77.63 m. Changes in lung function and quality of life were not observed. It was not possible to quantitatively analyze data on endothelial function and oxidative stress.

CONCLUSION

IMT improves MIP, MEP, and functional capacity in people living with CKD and receiving HD. IMT did not demonstrate significant results for lung function and quality of life. Effects on endothelial function and oxidative capacity remain uncertain.

IMPACT

Inspiratory muscle training improves MIP, MEP, and functional capacity in people living with CKD and receiving HD, compared with conventional physical therapy or controls or placebo intervention. Increases in functional capacity in this population are extremely important because of the relationship with the survival of these people.

Correlation Between Adiponectin Level and Ischemic Stroke Risk and Patient Prognosis: An Updated Meta-Analysis

Introduction

Adiponectin is a factor secreted by adipocytes and has been shown to play an important role in many physiological and pathological processes. Previous studies have shown that adiponectin levels are closely related to the occurrence and prognosis of ischemic stroke, but the results of different studies are conflicting. Therefore, this study aimed to update the data in this area to explore the relationship between adiponectin levels and the occurrence and prognosis of ischemic stroke.

Results

After searching 762 records, 14 studies were finally included, including 10 studies on the incidence of ischemic stroke and 4 studies on the prognosis of patients with ischemic stroke. The results of Meta-analysis showed that the correlation between the level of adiponectin and the occurrence and prognosis of ischemic stroke was not significant. The risk of ischemic stroke was not significantly changed in the population with high adiponectin levels (pooled RR=1.00, 95% CI=0.86-1.16, P=1.00). Similarly, there was no significant difference in all-cause mortality among those with high adiponectin levels compared with ischemic stroke patients with low adiponectin levels (pooled RR 0.61, 95% CI 0.47-0.80). However, significant heterogeneity was found during the meta-analysis, P<0.0001; I2=72% and P<0.0001; I2=88%, respectively. Subgroup analysis showed that factors such as study design, follow-up time and publication time could partly explain this heterogeneity.

Conclusions

In conclusion, adiponectin level is not significantly correlated with the occurrence and prognosis of ischemic stroke, suggesting that adiponectin level may not be used as a potential biomarker for ischemic stroke risk assessment and patient prognosis prediction.

Multi-step regulation of microRNA expression and secretion into small extracellular vesicles by insulin

Tissues release microRNAs (miRNAs) in small extracellular vesicles (sEVs) including exosomes, which can regulate gene expression in distal cells, thus acting as modulators of local and systemic metabolism. Here, we show that insulin regulates miRNA secretion into sEVs from 3T3-L1 adipocytes and that this process is differentially regulated from cellular expression. Thus, of the 53 miRNAs upregulated and 66 miRNAs downregulated by insulin in 3T3-L1 sEVs, only 12 were regulated in parallel in cells. Insulin regulated this process in part by phosphorylating hnRNPA1, causing it to bind to AU-rich motifs in miRNAs, mediating their secretion into sEVs. Importantly, 43% of insulin-regulated sEV-miRNAs are implicated in obesity and insulin resistance. These include let-7 and miR-103, which we show regulate insulin signaling in AML12 hepatocytes. Together, these findings demonstrate an important layer to insulin's regulation of adipose biology and provide a mechanism of tissue crosstalk in obesity and other hyperinsulinemic states.

Depleting inositol pyrophosphate 5-InsP7 protected the heart against ischaemia-reperfusion injury by elevating plasma adiponectin

AIMS

Adiponectin is an adipocyte-derived circulating protein that exerts cardiovascular and metabolic protection. Due to the futile degradation of endogenous adiponectin and the challenges of exogenous administration, regulatory mechanisms of adiponectin biosynthesis are of significant pharmacological interest.

METHODS AND RESULTS

Here, we report that 5-diphosphoinositol 1,2,3,4,6-pentakisphosphate (5-InsP7) generated by inositol hexakisphosphate kinase 1 (IP6K1) governed circulating adiponectin levels via thiol-mediated protein quality control in the secretory pathway. IP6K1 bound to adiponectin and DsbA-L and generated 5-InsP7 to stabilize adiponectin/ERp44 and DsbA-L/Ero1-Lα interactions, driving adiponectin intracellular degradation. Depleting 5-InsP7 by either IP6K1 deletion or pharmacological inhibition blocked intracellular adiponectin degradation. Whole-body and adipocyte-specific deletion of IP6K1 boosted plasma adiponectin levels, especially its high molecular weight forms, and activated AMPK-mediated protection against myocardial ischaemia-reperfusion injury. Pharmacological inhibition of 5-InsP7 biosynthesis in wild-type but not adiponectin knockout mice attenuated myocardial ischaemia-reperfusion injury.

CONCLUSION

Our findings revealed that 5-InsP7 is a physiological regulator of adiponectin biosynthesis that is amenable to pharmacological intervention for cardioprotection.

Identification of circulating apolipoprotein M as a new determinant of insulin sensitivity and relationship with adiponectin

BACKGROUND

The adiponectin is one of the rare adipokines down-regulated with obesity and protects against obesity-related disorders. Similarly, the apolipoprotein M (apoM) is expressed in adipocytes and its expression in adipose tissue is associated with metabolic health. We compared circulating apoM with adiponectin regarding their relationship with metabolic parameters and insulin sensitivity and examined their gene expression patterns in adipocytes and in the adipose tissue.

METHODS

Circulating apoM and adiponectin were examined in 169 men with overweight in a cross-sectional study, and 13 patients with obesity during a surgery-induced slimming program. Correlations with clinical parameters including the insulin resistance index (HOMA-IR) were analyzed. Multiple regression analyses were performed on HOMA-IR. The APOM and ADIPOQ gene expression were measured in the adipose tissue from 267 individuals with obesity and a human adipocyte cell line.

RESULTS

Participants with type 2 diabetes had lower circulating adiponectin and apoM, while apoM was higher in individuals with dyslipidemia. Similar to adiponectin, apoM showed negative associations with HOMA-IR and hs-CRP (r < -0.2), and positive correlations with HDL markers (HDL-C and apoA-I, r > 0.3). Unlike adiponectin, apoM was positively associated with LDL markers (LDL-C and apoB100, r < 0.20) and negatively correlated with insulin and age (r < -0.2). The apoM was the sole negative determinant of HOMA-IR in multiple regression models, while adiponectin not contributing significantly. After surgery, the change in HOMA-IR was negatively associated with the change in circulating apoM (r = -0.71), but not with the change in adiponectin. The APOM and ADIPOQ gene expression positively correlated in adipose tissue (r > 0.44) as well as in adipocytes (r > 0.81). In adipocytes, APOM was downregulated by inflammatory factors and upregulated by adiponectin.

CONCLUSIONS

The apoM rises as a new partner of adiponectin regarding insulin sensitivity. At the adipose tissue level, the adiponectin may be supported by apoM to promote a healthy adipose tissue.

TRIAL REGISTRATION

NCT01277068, registered 13 January 2011; NCT02332434, registered 5 January 2015; and NCT00390637, registered 20 October 2006.

Reversing Pdgfrβ Signaling Restores Metabolically Active Beige Adipocytes by Alleviating ILC2 Suppression in Aged and Obese Mice

Objective

Platelet Derived Growth Factor Receptor Beta (Pdgfrβ) suppresses the formation of cold temperature-induced beige adipocytes in aged mammals. We aimed to determine if deleting Pdgfrβ in aged mice could rejuvenate metabolically active beige adipocytes by activating group 2 innate lymphoid cells (ILC2), and whether this effect could counteract diet-induced obesity-associated beige fat decline.

Methods

We employed Pdgfrβ gain-of-function and loss-of-function mouse models targeting beige adipocyte progenitor cells (APCs). Our approach included cold exposure, metabolic cage analysis, and age and diet-induced obesity models to examine beige fat development and metabolic function under varied Pdgfrβ activity.

Results

Acute cold exposure alone enhanced metabolic benefits in aged mice, irrespective of beige fat generation. However, Pdgfrβ deletion in aged mice reestablished the formation of metabolically functional beige adipocytes, enhancing metabolism. Conversely, constitutive Pdgfrβ activation in young mice stymied beige fat development. Mechanistically, Pdgfrβ deletion upregulated IL-33, promoting ILC2 recruitment and activation, whereas Pdgfrβ activation reduced IL-33 levels and suppressed ILC2 activity. Notably, diet-induced obesity markedly increased Pdgfrβ expression and Stat1 signaling, which inhibited IL-33 induction and ILC2 activation. Genetic deletion of Pdgfrβ restored beige fat formation in obese mice, improving whole-body metabolism.

Conclusion

This study reveals that cold temperature exposure alone can trigger metabolic activation in aged mammals. However, reversing Pdgfrβ signaling in aged and obese mice not only restores beige fat formation but also renews metabolic function and enhances the immunological environment of white adipose tissue (WAT). These findings highlight Pdgfrβ as a crucial target for therapeutic strategies aimed at combating age- and obesity-related metabolic decline.

Improvement of Theaflavins on Glucose and Lipid Metabolism in Diabetes Mellitus

In diabetes mellitus, disordered glucose and lipid metabolisms precipitate diverse complications, including nonalcoholic fatty liver disease, contributing to a rising global mortality rate. Theaflavins (TFs) can improve disorders of glycolipid metabolism in diabetic patients and reduce various types of damage, including glucotoxicity, lipotoxicity, and other associated secondary adverse effects. TFs exert effects to lower blood glucose and lipids levels, partly by regulating digestive enzyme activities, activation of OATP-MCT pathway and increasing secretion of incretins such as GIP. By the Ca2+-CaMKK ꞵ-AMPK and PI3K-AKT pathway, TFs promote glucose utilization and inhibit endogenous glucose production. Along with the regulation of energy metabolism by AMPK-SIRT1 pathway, TFs enhance fatty acids oxidation and reduce de novo lipogenesis. As such, the administration of TFs holds significant promise for both the prevention and amelioration of diabetes mellitus.

The effect of plasma cytokines on the expression of adiponectin and its receptors in the synovial membrane of joints and the infrapatellar fat pad in patients with rheumatoid arthritis and osteoarthritis

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease that leads to joint destruction. Numerous pro-inflammatory mediators, including adipokines, play an important role in the pathogenesis of RA.

OBJECTIVE

The aim of the study was to investigate the relationships between selected plasma cytokines and expression of adiponectin and its receptors in the synovium and the infrapatellar fat pad in patients with RA and osteoarthritis (OA).

METHODS

Blood, synovium and fat pad samples from 18 patients with RA and 18 with OA were collected during joint replacement surgery. Spearman rank correlations between plasma concentrations of selected cytokines (IL-1β, IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12 p40, IL-13, IL-17, G-CSF and GM-CSF) and the expression of adiponectin and its receptors were determined. Plasma levels of cytokines were determined using a magnetic bead-based multiplex assay, mRNA expression of adiponectin and its receptors were determined by real-time PCR.

RESULTS

In OA patients, there were significant positive correlations between adiponectin expression in the synovial membrane and plasma levels of IL-1β, IL-4, G-CSF and GM-CSF, as well as a significant positive correlation between adiponectin expression in the fat pad and plasma levels of GM-CSF. In addition, OA patients showed significant negative correlations between AdipoR1 and AdipoR2 expression in the synovial membrane and plasma IL-6 levels, as well as between AdipoR2 expression in the synovial membrane and plasma MCP-1 and TNF-α levels. In patients with RA, there were no significant correlations between adiponectin expression in the synovial membrane and infrapatellar fat pad and plasma levels of the cytokines studied. In addition, RA patients showed a statistically significant negative correlation between AdipoR1 expression in the synovial membrane and plasma levels of TNF-α, IL-7, IL-12 and IL-13, and a significant negative correlation between AdipoR1 expression in the infrapatellar fat pad and plasma levels of IL-1β.

CONCLUSIONS

Adiponectin and its receptors showed the correlations with several plasma cytokines, however, a thorough understanding of the role of adiponectin in RA and OA requires further investigation.

Adipokines in depressed women with and without adverse childhood experiences

BACKGROUND

Adverse childhood experiences (ACE) elevate the risk of both major depressive disorder (MDD) and metabolic diseases. The underlying pathophysiology might include alterations of adipokine levels as a consequence of ACE. In this study, we used a full-factorial design to investigate the levels of select adipokines in women with ACE-only (n = 23), MDD-only (n = 27), ACE+MDD (n = 25) and healthy controls (HC, n = 29) to identify metabolic makers associated with vulnerability and resilience of developing MDD after ACE exposure.

METHODS

Serum levels of adiponectin, leptin, adiponectin-to-leptin (A/L) ratio, and retinol binding protein 4 (RBP4) were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Adiponectin levels did not differ between groups. Individuals with vs. without MDD showed higher leptin serum concentrations. As predicted, A/L ratio indicated lower values in individuals with vs. without ACE. RBP4 showed a more nuanced pattern with reduced levels in the ACE-only and MDD-only groups compared to HC. Furthermore, the ACE-only group showed lower RBP4 concentrations compared to ACE+MDD. These results were not accounted by BMI or medication status.

CONCLUSION

Our results do not support the utility of adiponectin and leptin as predictors of vulnerability or resilience of developing MDD after ACE. In contrast, RBP4 might play a role in resilience towards the development of MDD following ACE. Further research on this more recently discovered adipokine seems warranted.

Rab18 maintains homeostasis of subcutaneous adipose tissue to prevent obesity-induced metabolic disorders

Metabolically healthy obesity refers to obese individuals who do not develop metabolic disorders. These people store fat in subcutaneous adipose tissue (SAT) rather than in visceral adipose tissue (VAT). However, the molecules participating in this specific scenario remain elusive. Rab18, a lipid droplet (LD)-associated protein, mediates the contact between the endoplasmic reticulum (ER) and LDs to facilitate LD growth and maturation. In the present study, we show that the protein level of Rab18 is specifically upregulated in the SAT of obese people and mice. Rab18 adipocyte-specific knockout (Rab18 AKO) mice had a decreased volume ratio of SAT to VAT compared with wildtype mice. When subjected to high-fat diet (HFD), Rab18 AKO mice had increased ER stress and inflammation, reduced adiponectin, and decreased triacylglycerol (TAG) accumulation in SAT. In contrast, TAG accumulation in VAT, brown adipose tissue (BAT) or liver of Rab18 AKO mice had a moderate increase without ER stress stimulation. Rab18 AKO mice developed insulin resistance and systematic inflammation. Rab18 AKO mice maintained body temperature in response to acute and chronic cold induction with a thermogenic SAT, similar to the counterpart mice. Furthermore, Rab18-deficient 3T3-L1 adipocytes were more prone to palmitate-induced ER stress, indicating the involvement of Rab18 in alleviating lipid toxicity. Rab18 AKO mice provide a good animal model to investigate metabolic disorders such as impaired SAT. In conclusion, our studies reveal that Rab18 is a key and specific regulator that maintains the proper functions of SAT by alleviating lipid-induced ER stress.

The mysterious association between adiponectin and endometriosis

Adiponectin is a pleiotropic cytokine predominantly derived from adipose tissue. In addition to its role in regulating energy metabolism, adiponectin may also be related to estrogen-dependent diseases, and many studies have confirmed its involvement in mediating diverse biological processes, including apoptosis, autophagy, inflammation, angiogenesis, and fibrosis, all of which are related to the pathogenesis of endometriosis. Although many researchers have reported low levels of adiponectin in patients with endometriosis and suggested that it may serve as a protective factor against the development of the disease. Therefore, the purpose of this review was to provide an up-to-date summary of the roles of adiponectin and its downstream cytokines and signaling pathways in the aforementioned biological processes. Further systematic studies on the molecular and cellular mechanisms of action of adiponectin may provide novel insights into the pathophysiology of endometriosis as well as potential therapeutic targets.