Proteolytic cleavage product of 30-kDa adipocyte complement-related protein increases fatty acid oxidation in muscle and causes weight loss in mice

ADPN Regulates Oxidative Stress-Induced Follicular Atresia in Geese by Modulating Granulosa Cell Apoptosis and Autophagy

Geese are susceptible to oxidative stress during reproduction, which can lead to follicular atresia and impact egg production. Follicular atresia is directly triggered by the apoptosis and autophagy of granulosa cells (GCs). Adiponectin (ADPN), which is secreted by adipose tissue, has good antioxidant and anti-apoptotic capacity, but its role in regulating the apoptosis of GCs in geese is unclear. To investigate this, this study examined the levels of oxidative stress, apoptosis, and autophagy in follicular tissues and GCs using RT-qPCR, Western blotting, immunofluorescence, flow cytometry, transcriptomics and other methods. Atretic follicles exhibited high levels of oxidative stress and apoptosis, and autophagic flux was obstructed. Stimulating GCs with H2O2 produced results similar to those of atretic follicles. The effects of ADPN overexpression and knockdown on oxidative stress, apoptosis and autophagy in GCs were investigated. ADPN was found to modulate autophagy and reduced oxidative stress and apoptosis in GCs, in addition to protecting them from H2O2-induced damage. These results may provide a reasonable reference for improving egg-laying performance of geese.

A novel blood-based bioassay to monitor adiponectin signaling

The diverse beneficial effects of adiponectin-receptor signaling, including its impact on the regulation of inflammatory processes in vivo, have resulted in development of adiponectin receptor agonists as a treatment for metabolic disorders. However, there are no established non-invasive bioassays for detection of adiponectin target engagement in humans or animal models. Here, we designed an assay using small amounts of blood to assess adiponectin action. Specifically, we tested effects of the small 10-amino acid peptide adiponectin receptor agonist, ALY688, in a sublethal LPS endotoxemia model in mice. LPS-induced pro-inflammatory cytokine levels in serum were significantly reduced in mice treated with ALY688, assessed via multiplex ELISA in flow cytometry. Furthermore, ALY688 alone significantly induced TGF-β release in serum 1 h after treatment and was elevated for up to 24 h. Additionally, using a flow-cytometry panel for detection of changes in circulating immune cell phenotypes, we observed a significant increase in absolute T cell counts in mice after ALY688 treatment. To assess changes in intracellular signaling effectors downstream of adiponectin, phospho-flow cytometry was conducted. There was a significant increase in phosphorylation of AMPK and p38-MAPK in mice after ALY688 treatment. We then used human donor immune cells (PBMCs) treated with ALY688 ex vivo and observed elevation of AMPK and p38-MAPK phosphorylation from baseline in response to ALY688. Together, these results indicate we can detect adiponectin action on immune cells in vivo by assessing adiponectin signaling pathway for AMPK and p38-MAPK, as well as pro-inflammatory cytokine levels. This new approach provides a blood-based bioassay for screening adiponectin action.

New advances of adiponectin in regulating obesity and related metabolic syndromes

Obesity and related metabolic syndromes have been recognized as important disease risks, in which the role of adipokines cannot be ignored. Adiponectin (ADP) is one of the key adipokines with various beneficial effects, including improving glucose and lipid metabolism, enhancing insulin sensitivity, reducing oxidative stress and inflammation, promoting ceramides degradation, and stimulating adipose tissue vascularity. Based on those, it can serve as a positive regulator in many metabolic syndromes, such as type 2 diabetes (T2D), cardiovascular diseases, non-alcoholic fatty liver disease (NAFLD), sarcopenia, neurodegenerative diseases, and certain cancers. Therefore, a promising therapeutic approach for treating various metabolic diseases may involve elevating ADP levels or activating ADP receptors. The modulation of ADP genes, multimerization, and secretion covers the main processes of ADP generation, providing a comprehensive orientation for the development of more appropriate therapeutic strategies. In order to have a deeper understanding of ADP, this paper will provide an all-encompassing review of ADP.

Decreased AdipoR1 signaling and its implications for obesity-induced male infertility

Obesity is among the risk factors for male infertility. Although several mechanisms underlying obesity-induced male subfertility have been reported, the entire mechanism of obesity-induced male infertility still remains unclear. Here, we show that sperm count, sperm motility and sperm fertilizing ability were decreased in male mice fed a high-fat diet and that the expression of the AdipoR1 gene and protein was decreased, and the expression of pro-apoptotic genes and protein increased, in the testis from mice fed a high-fat diet. Moreover, we demonstrate that testes weight, sperm count, sperm motility and sperm fertilizing ability were significantly decreased in AdipoR1 knockout mice compared to those in wild-type mice; furthermore, the phosphorylation of AMPK was decreased, and the expression of pro-apoptotic genes and proteins, caspase-6 activity and pathologically apoptotic seminiferous tubules were increased, in the testis from AdipoR1 knockout mice. Furthermore, study findings show that orally administrated AdipoRon decreased caspase-6 activity and apoptotic seminiferous tubules in the testis, thus ameliorating sperm motility in male mice fed a high-fat diet. This was the first study to demonstrate that decreased AdipoR1/AMPK signaling led to increased caspase-6 activity/increased apoptosis in the testis thus likely accounting for male infertility.

Adiponectin protects against myocardial ischemia-reperfusion injury: a systematic review and meta-analysis of preclinical animal studies

BACKGROUND

Myocardial ischemia-reperfusion injury (MIRI) is widespread in the treatment of ischemic heart disease, and its treatment options are currently limited. Adiponectin (APN) is an adipocytokine with cardioprotective properties; however, the mechanisms of APN in MIRI are unclear. Therefore, based on preclinical (animal model) evidence, the cardioprotective effects of APN and the underlying mechanisms were explored.

METHODS

The literature was searched for the protective effect of APN on MIRI in six databases until 16 November 2023, and data were extracted according to selection criteria. The outcomes were the size of the myocardial necrosis area and hemodynamics. Markers of oxidation, apoptosis, and inflammation were secondary outcome indicators. The quality evaluation was performed using the animal study evaluation scale recommended by the Systematic Review Center for Laboratory animal Experimentation statement. Stata/MP 14.0 software was used for the summary analysis.

RESULTS

In total, 20 papers with 426 animals were included in this study. The pooled analysis revealed that APN significantly reduced myocardial infarct size [weighted mean difference (WMD) = 16.67 (95% confidence interval (CI) = 13.18 to 20.16, P < 0.001)] and improved hemodynamics compared to the MIRI group [Left ventricular end-diastolic pressure: WMD = 5.96 (95% CI = 4.23 to 7.70, P < 0.001); + dP/dtmax: WMD = 1393.59 (95% CI = 972.57 to 1814.60, P < 0.001); -dP/dtmax: WMD = 850.06 (95% CI = 541.22 to 1158.90, P < 0.001); Left ventricular ejection fraction: WMD = 9.96 (95% CI = 7.29 to 12.63, P < 0.001)]. Apoptosis indicators [caspase-3: standardized mean difference (SMD) = 3.86 (95% CI = 2.97 to 4.76, P < 0.001); TUNEL-positive cells: WMD = 13.10 (95% CI = 8.15 to 18.05, P < 0.001)], inflammatory factor levels [TNF-α: SMD = 4.23 (95% CI = 2.48 to 5.98, P < 0.001)], oxidative stress indicators [Superoxide production: SMD = 4.53 (95% CI = 2.39 to 6.67, P < 0.001)], and lactate dehydrogenase levels [SMD = 2.82 (95% CI = 1.60 to 4.04, P < 0.001)] were significantly reduced. However, the superoxide dismutase content was significantly increased [SMD = 1.91 (95% CI = 1.17 to 2.65, P < 0.001)].

CONCLUSION

APN protects against MIRI via anti-inflammatory, antiapoptotic, and antioxidant effects, and this effect is achieved by activating different signaling pathways.

The Role of Adipokines in the Control of Pituitary Functions

The pituitary gland is a key endocrine gland in all classes of vertebrates, including mammals. The pituitary gland is an important component of hypothalamus-pituitary-target organ hormonal regulatory axes and forms a functional link between the nervous system and the endocrine system. In response to hypothalamic stimuli, the pituitary gland secretes a number of hormones involved in the regulation of metabolism, stress reactions and environmental adaptation, growth and development, as well as reproductive processes and lactation. In turn, hormones secreted by target organs at the lowest levels of the hormonal regulatory axes regulate the functions of the pituitary gland in the process of hormonal feedback. The pituitary also responds to other peripheral signals, including adipose-tissue-derived factors. These substances are a broad group of peptides known as adipocytokines or adipokines that act as endocrine hormones mainly involved in energy homeostasis. Adipokines, including adiponectin, resistin, apelin, chemerin, visfatin, and irisin, are also expressed in the pituitary gland, and they influence the secretory functions of this gland. This review is an overview of the existing knowledge of the relationship between chosen adipose-derived factors and endocrine functions of the pituitary gland, with an emphasis on the pituitary control of reproductive processes.

Sex-specific adipose tissue's dynamic role in metabolic and inflammatory response following peripheral nerve injury

Epidemiological data and research highlight increased neuropathy and chronic pain prevalence among females, spanning metabolic and normometabolic contexts, including murine models. Prior findings demonstrated diverse immune and neuroimmune responses between genders in neuropathic pain (NeP), alongside distinct protein expression in sciatic nerves. This study unveils adipose tissue's (AT) role in sex-specific NeP responses after peripheral nerve injury. Metabolic assessments, metabolomics, energy expenditure evaluations, AT proteomic analyses, and adipokine mobilization depict distinct AT reactions to nerve damage. Females exhibit altered lipolysis, fatty acid oxidation, heightened energy expenditure, and augmented steroids secretion affecting glucose and insulin metabolism. Conversely, male neuropathy prompts glycolysis, reduced energy expenditure, and lowered unsaturated fatty acid levels. Males' AT promotes regenerative molecules, oxidative stress defense, and stimulates peroxisome proliferator-activated receptors (PPAR-γ) and adiponectin. This study underscores AT's pivotal role in regulating gender-specific inflammatory and metabolic responses to nerve injuries, shedding light on female NeP susceptibility determinants.

Excessive Pregestational Weight and Maternal Obstetric Complications: The Role of Adipokines

There is a high frequency of overweight and obesity in women of reproductive age. Women who start pregnancy with overweight or obesity have an increased risk of developing maternal obstetric complications such as gestational hypertension, pre-eclampsia, gestational diabetes mellitus, postpartum hemorrhage, and requiring C-section to resolve the pregnancy with a higher risk of C-section surgical site infection. Excessive weight in pregnancy is characterized by dysregulation of adipokines, the functions of which partly explain the predisposition of pregnant women with overweight or obesity to these maternal obstetric complications. This review compiles, organizes, and analyzes the most recent studies on adipokines in pregnant women with excess weight and the potential pathophysiological mechanisms favoring the development of maternal pregnancy complications.

Zinc nanoparticles ameliorated obesity-induced cardiovascular disease: role of metabolic syndrome and iron overload

Obesity is a complicated disease characterized by abundant fat accumulation. It is associated with cardiovascular disease. The current study aimed to appreciate the role of synthesized zinc oxide nanoparticles (ZnONPs) (18.72 nm in size) in curbing cardiovascular disease in an obesity model of a high fat/sucrose diet in male rats. For 16 weeks, 24 rats were fed a high-fat diet and a 25% sucrose solution to develop obesity, and after that, the rats were randomly allocated into four groups of rats. Group 1 served as the control group and consisted of normal, non-obese rats. Group 2 comprised obese rats that were injected with an equivalent volume of a neutral substance, serving as vehicle control. In Group 3 or 4, obese rats were treated with an intraperitoneal injection of 5 or 10mg/kg of zinc oxide nanoparticles (ZnONPs) for eight weeks. The treatment of obese rats with ZnONPs decreased plasma levels of monocyte chemoattractant Protein-1 (MCP-1), resistin, ENA78, tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL6), and C reactive protein (CRP). Also, the remediation of obese rats with ZnONPs led to a significant decrease in body mass index (BMI), body weight gain, leptin, cholesterol, triglycerides, LDL (Low-density lipoprotein), glucose, and insulin resistance index (HOMA-IR). Moreover, ZnONPs treatment lowered troponin, creatine phosphokinase-MB (CK-MB), lactate dehydrogenase (LDH), cardiac or adipose tissue iron content, and malondialdehyde (MDA) either in blood or heart tissue. Otherwise, treating obese rats with ZnONPs enhanced plasma adiponectin levels, cardiac-reduced glutathione (GSH), and superoxide dismutase (SOD). In addition, ZnONPs displayed a significant influence on the cardiovascular system since they combat the rise in blood pressure and the pathological changes of the heart and aorta besides maintaining plasma nitric oxide levels. The results showed a positive correlation between BMI and MDA, MPC-1, CK-MB, and LDH. ZnONPs are convenient in treating cardiovascular disease in obese rats via reduced blood pressure, oxidative stress, cardiac iron accumulation, insulin resistance, and inflammatory markers.

Association Between Adipokine Profile, Systemic Inflammation, Muscle and Protein Energy Wasting in Children With Chronic Kidney Disease

OBJECTIVES

This cross-sectional study explores the association of adipokines and interleukin-6 (IL-6) with muscle and protein energy wasting (PEW) in children with chronic kidney disease (CKD).

METHODS

We measured serum adiponectin, leptin, resistin and IL-6 in 53 patients with CKD stage 3-5. Lean tissue (LTI) and fat tissue index (FTI) were estimated by bioimpedance analysis spectroscopy. PEW was defined as muscle wasting [LTI adjusted to height age (LTI HA) z-score < -1.65 SD) and at least 2 of the following: reduced body mass [body mass index adjusted to height age (BMI HA) z-score < -1.65 SD), poor growth [height z-score < -1.88 SD], questionnaire-based decreased appetite, and serum albumin ≤3.8 g/dL.

RESULTS

PEW, observed in 8 (15.1%) patients, was more prevalent in CKD stage 5 (P = .010). Among the adipokines, adiponectin, and resistin levels were significantly higher in CKD stage 5 (P < .001, P = .005). Adiponectin was correlated to LTI HA z-score (Rs = -0.417, P = .002), leptin to FTI z-score (Rs = 0.620, P < .001), while no correlation was observed between resistin and body composition parameters. Resistin was the only adipokine correlated to IL-6 (Rs = 0.513, P < .001). After adjustment for CKD stage and patient age, PEW was associated with adiponectin and IL-6 rise by 1 μg/mL and 10 pg/mL respectively (odds ratio (OR) 1.240, 95% confidence interval (CI) 1.040, 1.478 and OR 1.405, 95% CI 1.075-1.836) but not with leptin, while resistin association with PEW lost its significance.

CONCLUSIONS

In pediatric CKD, adiponectin is associated with muscle wasting, leptin with adiposity and resistin with systemic inflammation. Adiponectin and cytokine IL-6 may serve as PEW biomarkers.

Relationship between chronic obstructive pulmonary disease and adiponectin concentrations: An updated meta-analysis and single-cell RNA sequencing

BACKGROUND

Adipose tissue, being an organ of the endocrine system, can influence the severity of chronic obstructive pulmonary disease (COPD). Even though several inflammatory markers can potentially significantly influence lung function, the precise function of adipokines, like adiponectin, in COPD is still disputed. To analyze the association of COPD with adiponectin concentrations, a meta-analysis of the most recent literature and single-cell sequencing data were conducted.

METHODS

Studies in Embase, PubMed, Cochrane Library, and Web of Science were browsed to obtain relevant data, which were then assessed with the aid of R 4.1.3 and STATA 11.0 software. Standardized mean differences and correlation coefficients aided the analysis of effect values. Moreover, a single-cell sequencing GSE136831 dataset was retrieved to ascertain the mRNA expression of adiponectin gene (ADIPOQ) in the lung tissue of COPD patients to confirm the difference in the expression of adiponectin between the case and control groups.

RESULTS

This meta-analysis comprised 18 publications involving 24 studies. The overall combined data established the concentration of plasma/serum adiponectin as significantly higher in patients with COPD compared to healthy subjects. Subgroup analyses based on disease status, specimen type, ethnicity, study design method, measurement method, and age of COPD patients demonstrated that all patients with COPD had elevated levels of adiponectin compared to healthy controls. When subgroup analysis was performed for gender alone, the results depicted that male COPD patients had significantly higher adiponectin than healthy males, while female patients of COPD had elevated adiponectin compared to healthy females. Furthermore, it was found that plasma/serum adiponectin appeared to be positively correlated with tumor necrosis factor-α, and it was negatively correlated with FEV1% and FEV1/FVC. The results of single-cell sequencing data suggested that ADIPOQ mRNA was mainly expressed in alveolar epithelial cells, and the level of ADIPOQ mRNA was higher in lung tissues of patients with COPD than in lung tissues of healthy subjects.

CONCLUSION

This meta-analysis suggests that the levels of plasma/serum adiponectin are significantly elevated in patients with COPD versus controls. Tumor necrosis factor-α, FEV1/FVC, and FEV1% may all be associated with the concentrations of adiponectin.

E4orf1 improves adipose tissue-specific metabolic risk factors and indicators of cognition function in a mouse model of Alzheimer's disease

OBJECTIVE

Obesity, impaired glycemic control, and hepatic steatosis often coexist and are risk factors for developing dementia, and Alzheimer's disease (AD). We hypothesized that a therapeutic agent that improves glycemic control and steatosis may attenuate obesity-associated progression of dementia. We previously identified that adenoviral protein E4orf1 improves glycemic control and reduces hepatic steatosis despite obesity in mice. Here, we determined if this metabolic improvement by E4orf1 will ameliorate cognitive decline in a transgenic mouse model of AD.

METHODS

Fourteen- to twenty-month-old APP/PS1/E4orf1 and APP/PS1 (control) mice were fed a high-fat diet. Cognition was determined by Morris Water Maze (MWM). Systemic glycemic control and metabolic signaling changes in adipose tissue, liver, and brain were determined.

RESULTS

Compared to control, E4orf1 expression significantly improved glucose clearance, reduced endogenous insulin requirement and lowered body-fat, enhanced glucose and lipid metabolism in adipose tissue, and reduced de novo lipogenesis in the liver. In the brain, E4orf1 mice displayed significantly greater expression of genes involved in neurogenesis and amyloid-beta degradation and performed better in MWM testing.

CONCLUSION

This study opens-up the possibility of addressing glycemic control and steatosis for attenuating obesity-related cognitive decline. It also underscores the potential of E4orf1 for the purpose, which needs further investigations.

Characterizing 3T3-L1 MBX Adipocyte Cell Differentiation Maintained with Fatty Acids as an In Vitro Model to Study the Effects of Obesity

The increasing prevalence of obesity has prompted intensive research into understanding its role in pathogenesis and designing appropriate treatments. To determine the signals generated from the interaction of fat cells with a target organ, a reliable white adipocyte model in vitro is needed. Differentiated fibroblasts are the most extensively studied using in vitro cell models of white adipocytes. However, it can be argued that differentiated fibroblasts minimally recapitulate the consequences of obesity. Here, we describe 3T3-L1 MBX cells as a culture model for studying obese adipocytes and their effects. Differentiation of 3T3-L1 MBX cells was at first optimized and then maintained in the presence of fatty acids cocktail combination to induce the obese condition. Lipid accumulation and adipokine secretion profiles were analyzed. Results showed that fatty acid-maintained, differentiated 3T3-L1 MBX cells had significantly greater accumulation of lipids and significant changes in the adipokine secretions in comparison to differentiated 3T3-L1 MBX cells maintained in medium without fatty acids. To elucidate the molecular changes associated with adipogenesis and lipid accumulation profile of 3T3-L1 MBX cells, we have also explored the expression of some of the regulatory proteins related to the development and maintenance of adipocytes from the preadipocyte lineage.

Glucose Metabolism Indices and the Development of Chronic Kidney Disease: A Cohort Study of Middle-Aged and Elderly Chinese Persons

Objective

Chronic kidney disease (CKD) has become a major global health issue, and abnormalities of glucose metabolism are a risk factor responsible for development of CKD. We aimed to investigate associations between glucose metabolism indices and CKD in a Chinese population and determine which index is superior for predicting incident CKD.

Methods

We performed a community-based population on 5232 subjects aged ≥40 years without baseline CKD. CKD was defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 or urinary albumin-to-creatinine ratio (UACR) ≥30 mg/g. We examined the associations of glucose metabolism indices, including fasting plasma glucose (FPG), 2-hour (2 h) oral glucose tolerance test (OGTT), hemoglobin A1c (HbA1c), fasting insulin level, homeostasis model assessment of insulin resistance (HOMA-IR), and HOMA-β and the development of CKD.

Results

With an average follow-up of 3.6 years, 6.4% of the subjects developed CKD. Pearson's correlation analysis revealed that FPG, HbA1c, fasting insulin, and HOMA-IR were all significantly correlated with UACR and eGFR. The association persisted in multivariate linear regression analysis adjusted for age and sex. Compared with other glucose indices, HOMA-IR exhibited the strongest associations with CKD in COX multivariate regression analysis (HR = 1.17, 95% CI: 1.04-1.31).

Conclusion

HOMA-IR is superior to other routine indices of glucose metabolism for predicting the development of CKD in middle-aged Chinese persons. Screening with HOMA-IR may help prevent the development of CKD in the general population.

Adiponectin as a therapeutic target for diabetic foot ulcer

The global burden of diabetic foot ulcers (DFUs) is a significant public health concern, affecting millions of people worldwide. These wounds cause considerable suffering and have a high economic cost. Therefore, there is a need for effective strategies to prevent and treat DFUs. One promising therapeutic approach is the use of adiponectin, a hormone primarily produced and secreted by adipose tissue. Adiponectin has demonstrated anti-inflammatory and anti-atherogenic properties, and researchers have suggested its potential therapeutic applications in the treatment of DFUs. Studies have indicated that adiponectin can inhibit the production of pro-inflammatory cytokines, increase the production of vascular endothelial growth factor, a key mediator of angiogenesis, and inhibit the activation of the intrinsic apoptotic pathway. Additionally, adiponectin has been found to possess antioxidant properties and impact glucose metabolism, the immune system, extracellular matrix remodeling, and nerve function. The objective of this review is to summarize the current state of research on the potential role of adiponectin in the treatment of DFUs and to identify areas where further research is needed in order to fully understand the effects of adiponectin on DFUs and to establish its safety and efficacy as a treatment for DFUs in the clinical setting. This will provide a deeper understanding of the underlying mechanisms of DFUs that can aid in the development of new and more effective treatment strategies.

Adiponectin and leptin levels of patients after sleeve gastrectomy, Roux-en-Y gastric bypass, and single anastomosis sleeve ileal bypass surgeries

Background

Bariatric surgery is an appropriate treatment for obese patients with metabolic syndrome. Adipose tissue is an active endocrine tissue secreting leptin and adiponectin that affect body metabolism. Nowadays, a high incidence of metabolic syndrome with an increased risk of serious diseases has been detected in Shiraz. This study aimed to assess the levels of leptin and adiponectin as well as the adiponectin-to-leptin ratio in three different bariatric surgeries among obese patients in Shiraz. The results will play an important role in physicians' choice of surgery by distinguishing the effects of these three bariatric surgeries.

Materials and Methods

The serum adiponectin and leptin levels were measured using enzyme-linked immunosorbent assay. Blood glucose, lipid profile, weight, and liver enzyme level were measured before and 7 months after surgery.

Results

This clinical trial was conducted on 81 obese patients who underwent sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), and single anastomosis sleeve ileal (SASI) bypass surgeries. The results revealed a decrease in fasting blood sugar and triglyceride (TG) levels 7 months after the surgeries. In addition, decrease of body mass index (BMI) was more significantly in the SASI group (12.8 ± 3 4.95) compared to the Roux-en-Y gastric group (8.56 ± 4.61) (P = 0.026). Besides, a more significant improvement in liver function was observed in SG (P < 0.05). Furthermore, the results revealed a significant difference among the three groups regarding the increase in the adiponectin level (P = 0.039). Decrease in the leptin level and increase in the adiponectin level were more significant after the RYGB surgery compared to the SG group (P < 0.05).

Conclusion

The three bariatric surgeries were effective in increasing the adiponectin level and decreasing the leptin levels. The surgeries also changed the metabolic risk factors including TGs, high-density lipoprotein, fasting blood glucose, and BMI.

Molecular Mechanisms of Lipid-Based Metabolic Adaptation Strategies in Response to Cold

Temperature changes and periods of detrimental cold occur frequently for many organisms in their natural habitats. Homeothermic animals have evolved metabolic adaptation strategies to increase mitochondrial-based energy expenditure and heat production, largely relying on fat as a fuel source. Alternatively, certain species are able to repress their metabolism during cold periods and enter a state of decreased physiological activity known as torpor. By contrast, poikilotherms, which are unable to maintain their internal temperature, predominantly increase membrane fluidity to diminish cold-related damage from low-temperature stress. However, alterations of molecular pathways and the regulation of lipid-metabolic reprogramming during cold exposure are poorly understood. Here, we review organismal responses that adjust fat metabolism during detrimental cold stress. Cold-related changes in membranes are detected by membrane-bound sensors, which signal to downstream transcriptional effectors, including nuclear hormone receptors of the PPAR (peroxisome proliferator-activated receptor) subfamily. PPARs control lipid metabolic processes, such as fatty acid desaturation, lipid catabolism and mitochondrial-based thermogenesis. Elucidating the underlying molecular mechanisms of cold adaptation may improve beneficial therapeutic cold treatments and could have important implications for medical applications of hypothermia in humans. This includes treatment strategies for hemorrhagic shock, stroke, obesity and cancer.

The Effects of Smoking on the Diagnostic Characteristics of Metabolic Syndrome: A Review

Metabolic syndrome is a growing epidemic that increases the risk for cardiovascular disease, diabetes, stroke, and mortality. It is diagnosed by the presence of three or more of the following risk factors: 1) obesity, with an emphasis on central adiposity, 2) high blood pressure, 3) hyperglycemia, 4) dyslipidemia, with regard to reduced high-density lipoprotein concentrations, and 5) dyslipidemia, with regard to elevated triglycerides. Smoking is one lifestyle factor that can increase the risk for metabolic syndrome as it has been shown to exert negative effects on abdominal obesity, blood pressure, blood glucose concentrations, and blood lipid profiles. Smoking may also negatively affect other factors that influence glucose and lipid metabolism including lipoprotein lipase, adiponectin, peroxisome proliferator-activated receptors, and tumor necrosis factor-alpha. Some of these smoking-related outcomes may be reversed with smoking cessation, thus reducing the risk for metabolic disease; however, metabolic syndrome risk may initially increase post cessation, possibly due to weight gain. Therefore, these findings warrant the need for more research on the development and efficacy of smoking prevention and cessation programs.

Native adiponectin plays a role in the adipocyte-mediated conversion of fibroblasts to myofibroblasts

Adipocytes regulate tissues through production of adipokines that can act both locally and systemically. Adipocytes also have been found to play a critical role in regulating the healing process. To better understand this role, we developed a three-dimensional human adipocyte spheroid system that has an adipokine profile similar to in vivo adipose tissues. Previously, we found that conditioned medium from these spheroids induces human dermal fibroblast conversion into highly contractile, collagen-producing myofibroblasts through a transforming growth factor beta-1 (TGF-β1) independent pathway. Here, we sought to identify how mature adipocytes signal to dermal fibroblasts through adipokines to induce myofibroblast conversion. By using molecular weight fractionation, heat inactivation and lipid depletion, we determined mature adipocytes secrete a factor that is 30-100 kDa, heat labile and lipid associated that induces myofibroblast conversion. We also show that the depletion of the adipokine adiponectin, which fits those physico-chemical parameters, eliminates the ability of adipocyte-conditioned media to induce fibroblast to myofibroblast conversion. Interestingly, native adiponectin secreted by cultured adipocytes consistently elicited a stronger level of α-smooth muscle actin expression than exogenously added adiponectin. Thus, adiponectin secreted by mature adipocytes induces fibroblast to myofibroblast conversion and may lead to a phenotype of myofibroblasts distinct from TGF-β1-induced myofibroblasts.

The Role of Adipokines in Health and Disease

Adipokines are cell-signaling proteins secreted by adipose tissue that has been related to a low-grade state of inflammation and different pathologies. The present review aims to analyze the role of adipokines in health and disease in order to understand the important functions and effects of these cytokines. For this aim, the present review delves into the type of adipocytes and the cytokines produced, as well as their functions; the relations of adipokines in inflammation and different diseases such as cardiovascular, atherosclerosis, mental diseases, metabolic disorders, cancer, and eating behaviors; and finally, the role of microbiota, nutrition, and physical activity in adipokines is discussed. This information would allow for a better understanding of these important cytokines and their effects on body organisms.

Adiponectin reverses β-Cell damage and impaired insulin secretion induced by obesity

Obesity significantly decreases life expectancy and increases the incidence of age-related dysfunctions, including β-cell dysregulation leading to inadequate insulin secretion. Here, we show that diluted plasma from obese human donors acutely impairs β-cell integrity and insulin secretion relative to plasma from lean subjects. Similar results were observed with diluted sera from obese rats fed ad libitum, when compared to sera from lean, calorically restricted, animals. The damaging effects of obese circulating factors on β-cells occurs in the absence of nutrient overload, and mechanistically involves mitochondrial dysfunction, limiting glucose-supported oxidative phosphorylation and ATP production. We demonstrate that increased levels of adiponectin, as found in lean plasma, are the protective characteristic preserving β-cell function; indeed, sera from adiponectin knockout mice limits β-cell metabolic fluxes relative to controls. Furthermore, oxidative phosphorylation and glucose-sensitive insulin secretion, which are completely abrogated in the absence of this hormone, are restored by the presence of adiponectin alone, surprisingly even in the absence of other serological components, for both the insulin-secreting INS1 cell line and primary islets. The addition of adiponectin to cells treated with plasma from obese donors completely restored β-cell functional integrity, indicating the lack of this hormone was causative of the dysfunction. Overall, our results demonstrate that low circulating adiponectin is a key damaging element for β-cells, and suggest strong therapeutic potential for the modulation of the adiponectin signaling pathway in the prevention of age-related β-cell dysfunction.

Enriched functional milk fat ameliorates glucose intolerance and triacylglycerol accumulation in skeletal muscle of rats fed high-fat diets

PURPOSE

We examined the effect of a functional milk fat (FMF) on the glucose metabolism and its association with the intramuscular triacylglycerol (TAG) content in rats fed high-fat diets.

METHODS

Male Wistar rats were fed for 60 days with S7 (soybean oil 7%), S30 (soybean oil 30%), MF30 (soybean oil 3% + milk fat 27%), or FMF30 (soybean oil 3% + FMF 27%) diets. An oral glucose tolerance test was performed. The levels of key metabolites in gastrocnemius muscle and mRNA levels of genes involved in glucose and lipid metabolism in muscle, epididymal white adipose tissue (EWAT), and serum were assessed.

RESULTS

The S30 diet induced glucose intolerance and led to TAG, citrate, and glucose accumulation in muscle. Moreover, we observed a downregulation of uncoupling proteins (Ucp2 and Ucp3) and insulin receptor substrate-1 (Irs1) genes, lower carnitine palmitoyl transferase-1b (CPT-1b), and phosphofructokinase-1 (PFK1) activities in muscle and lower expression of adiponectin (Adipoq) in EWAT. The FMF30 diet ameliorated the glucose intolerance and normalized the glucose and TAG levels in muscle, preventing the accumulation of citrate and enhancing glucose utilization by the PFK1. The beneficial effects might also be related to the higher expression of Adipoq in EWAT, its receptor in muscle (Adipor1), and the expression of Ucp2, Ucp3, and Irs1 in muscle, restoring the alterations observed with the S30 diet.

CONCLUSIONS

FMF30 modulated key genes involved in glucose and lipid metabolism in skeletal muscle, improving the glucose utilization and preventing TAG, glucose, and citrate accumulation.

Potential Protective Function of Adiponectin in Diabetic Retinopathy

Adiponectin, one of the most ubiquitous adipokines found in the blood, plays a major role in glucolipid metabolism and energy metabolism and regulation. In recent years, a growing body of research indicates that adiponectin also plays a significant role in diabetic retinopathy. In the present review, we specifically address the protective effects of adiponectin on the development and progression of diabetic retinopathy through improvement in insulin resistance, alleviation of oxidative stress, limiting of inflammation, and prevention of vascular remodeling, with the aim to explore new potential approaches and targets for the prevention and treatment of diabetic retinopathy.

The Role of Adipokines in the Pathogenesis of Psoriasis

Psoriasis is a chronic and immune-mediated skin condition characterized by pro-inflammatory cytokines and keratinocyte hyperproliferation. Dendritic cells, T lymphocytes, and keratinocytes represent the main cell subtypes involved in the pathogenesis of psoriasis, while the interleukin-23 (IL-23)/IL-17 pathway enhances the disease progression. Human adipose tissue is an endocrine organ, which secretes multiple proteins, known as adipokines, such as adiponectin, leptin, visfatin, or resistin. Current evidence highlights the immunomodulatory roles of adipokines, which may contribute to the progression or suppression of psoriasis. A better understanding of the complexity of psoriasis pathophysiology linked with adipokines could result in developing novel diagnostic or therapeutic strategies. This review aims to present the pathogenesis of psoriasis and the roles of adipokines in this process.

Arbutin ameliorates hyperglycemia, dyslipidemia and oxidative stress and modulates adipocytokines and PPARγ in high-fat diet/streptozotocin-induced diabetic rats

Arbutin is a glycosylated hydroquinone with antioxidant and anti-hyperglycemia effects. However, its beneficial effects in type 2 diabetes (T2D) were not clarified. This study evaluated the effect of arbutin on hyperglycemia, dyslipidemia, insulin resistance, oxidative stress, and inflammatory response in T2D. Rats induced by high fat diet and streptozotocin were treated with arbutin (25 and 50 mg/kg for 4 weeks). Diabetic rats exhibited glucose intolerance, elevated HbA1c%, reduced insulin, and high HOMA-IR. Liver glycogen and hexokinase activity were decreased in T2D rats while glucose-6-phosphatase (G6Pase), fructose-1,6- biphosphatase (FBPase), and glycogen phosphorylase were upregulated. Circulating and hepatic cholesterol and triglycerides and serum transaminases were elevated in T2D rats. Arbutin ameliorated hyperglycemia, dyslipidemia, insulin deficiency and resistance, and liver glycogen and alleviated the activity of carbohydrate-metabolizing enzymes. Both doses of arbutin decreased serum transaminases and resistin, and liver lipids, TNF-α, IL-6, malondialdehyde and nitric oxide, downregulated liver resistin and fatty acid synthase, and increased serum and liver adiponectin, and liver reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). These effects were associated with the upregulation of hepatic PPARγ. Arbutin inhibited α-glucosidase in vitro and in silico investigations revealed the ability of arbutin to bind PPARγ, hexokinase, and α-glucosidase. In conclusion, arbutin effectively ameliorated glucose intolerance, insulin resistance, dyslipidemia, inflammation, and oxidative stress, and modulated carbohydrate-metabolizing enzymes, antioxidants, adipokines and PPARγ in T2D in rats.

Globular adiponectin ameliorates insulin resistance in skeletal muscle by enhancing the LKB1-mediated AMPK activation via SESN2

Adiponectin has been demonstrated to be a mediator of insulin sensitivity; however, the underlined mechanisms remain unclear. SESN2 is a stress-inducible protein that phosphorylates AMPK in different tissues. In this study, we aimed to validate the amelioration of insulin resistance by globular adiponectin (gAd) and to reveal the role of SESN2 in the improvement of glucose metabolism by gAd. We used a high-fat diet-induced wild-type and SESN2-/- C57BL/6J insulin resistance mice model to study the effects of six-week aerobic exercise or gAd administration on insulin resistance. In vitro study, C2C12 myotubes were used to determine the potential mechanism by overexpressing or inhibiting SESN2. Similar to exercise, six-week gAd administration decreased fasting glucose, triglyceride and insulin levels, reduced lipid deposition in skeletal muscle and reversed whole-body insulin resistance in mice fed on a high-fat diet. Moreover, gAd enhanced skeletal muscle glucose uptake by activating insulin signaling. However, these effects were diminished in SESN2-/- mice. We found that gAd administration increased the expression of SESN2 and Liver kinase B1 (LKB1) and increased AMPK-T172 phosphorylation in skeletal muscle of wild-type mice, while in SESN2-/- mice, LKB1 expression was also increased but the pAMPK-T172 was unchanged. At the cellular level, gAd increased cellular SESN2 and pAMPK-T172 expression. Immunoprecipitation experiment suggested that SESN2 promoted the formation of complexes of AMPK and LKB1 and hence phosphorylated AMPK. In conclusion, our results revealed that SESN2 played a critical role in gAd-induced AMPK phosphorylation, activation of insulin signaling and skeletal muscle insulin sensitization in mice with insulin resistance.

Identification of Putative Molecules for Adiponectin and Adiponectin Receptor and Their Roles in Learning and Memory in Lymnaea stagnalis

Adiponectin enhances insulin sensitivity, which improves cognition in mammals. How adiponectin affects the mechanism’s underlying cognition, however, remains unknown. We hypothesized that experiments using the pond snail Lymnaea stagnalis, which has long been used in learning and memory studies and in which the function of insulin-like peptides affect learning and memory, could clarify the basic mechanisms by which adiponectin affects cognition. We first identified putative molecules of adiponectin and its receptor in Lymnaea. We then examined their distribution in the central nervous system and changes in their expression levels when hemolymph glucose concentrations were intentionally decreased by food deprivation. We also applied an operant conditioning protocol of escape behavior to Lymnaea and examined how the expression levels of adiponectin and its receptor changed after the conditioned behavior was established. The results demonstrate that adiponectin and adiponectin’s receptor expression levels were increased in association with a reduced concentration of hemolymph glucose and that expression levels of both adiponectin and insulin-like peptide receptors were increased after the conditioning behavior was established. Thus, the involvement of the adiponectin-signaling cascade in learning and memory in Lymnaea was suggested to occur via changes in the glucose concentrations and the activation of insulin.

Presence, Tissue Localization, and Gene Expression of the Adiponectin Receptor 1 in Testis and Accessory Glands of Male Rams during the Non-Breeding Season

Adiponectin (ADIPOQ) is a member adipocytokines, and its actions are supported by two receptors, ADIPOQ receptor 1 and -2, respectively (ADIPOR1 and -R2). Our study was performed to evaluate the ADIPOR1 presence and location and its gene expression in reproductive tissues of the male ram, during its non-breading season. The different portions of the male ram reproductive system (testis, epididymis, seminal vesicle, ampoule vas deferens, bulb-urethral gland) were collected in a slaughterhouse. Immunohistochemistry showed ADIPOR1 positive signals in the cytoplasm of all the glandular epithelial cells, with a location near the nucleus; in the testes, the positive reaction was evidenced in the cytoplasm in the basal portion of the germinal epithelial cells. The immune reaction intensity was highest (p < 0.001) in the prostate and seminal vesicles glands than that of other parts of the ram reproductive tract. RT-qPCR detected the ADIPOR1 transcript in the testes, epididymis, vas deferens, bulbourethral glands, seminal vesicles, and prostate; the expression levels were high (p < 0.01) in the prostate and low (p < 0.01) in the testis, epididymis, and bulbourethral glands. The present results evidenced the possible ADIPOQ/ADIPOR1 system's role in regulating the testicular activity of male rams during the non-breading season.

Contribution of key elements of nutritional metabolism to the development of cystic ovarian disease in dairy cattle

The alteration of signaling molecules involved in the general metabolism of animals can negatively influence reproduction. In dairy cattle, the development of follicular cysts and the subsequent appearance of ovarian cystic disease (COD) often lead to decreased reproductive efficiency in the herd. The objective of this review is to summarize the contribution of relevant metabolic and nutritional sensors to the development of COD in dairy cows. In particular, we focus on the study of alterations of the insulin signaling pathway, adiponectin, and other sensors and metabolites relevant to ovarian functionality, which may be related to the development of follicular persistence and follicular formation of cysts in dairy cattle. The results of these studies support the hypothesis that systemic factors could alter the local scenario in the follicle, generating an adverse microenvironment for the resumption of ovarian activity and possibly leading to the persistence of follicles and to the development and recurrence of COD.

Sex-specific effects of CD248 on metabolism and the adipose tissue lipidome

Cd248 has recently been associated with adipose tissue physiology, demonstrated by reduced weight gain in high fat diet-fed mice with genetic deletion of Cd248 relative to controls. Here we set out to determine the metabolic consequences of loss of Cd248. Strikingly, we find these to be sex specific; By subjecting Cd248-/- and Cd248+/+ mice to a high fat diet and indirect calorimetry study, we identified that only male Cd248-/- mice show reduced weight gain compared to littermate control wildtype mice. In addition, male (but not female) mice showed a lower respiratory exchange ratio on both chow and high fat diets, indicating a predisposition to metabolise lipid. Lipidomic studies on specific fat depots found reduced triglyceride and diglyceride deposition in male Cd248-/- mice, and this was supported by reduced expression of lipogenic and adipogenic genes. Finally, metabolomic analysis of isolated, differentiated preadipocytes found alterations in metabolic pathways associated with lipid deposition in cells isolated from male, but not female, Cd248-/- mice. Overall, our results highlight the importance of sex controls in animal studies and point to a role for Cd248 in sex- and depot-specific regulation of lipid metabolism.

Effects of Anterior Pituitary Adenomas' Hormones on Glucose Metabolism and Its Clinical Implications

Pituitary adenomas have recently become more common and their incidence is increasing yearly. Functional pituitary tumors commonly secrete prolactin, growth hormones, and adrenocorticotropic hormones, which cause diseases such as prolactinoma, acromegaly, and Cushing's disease, but rarely secrete luteinizing, follicle-stimulating, thyroid-stimulating, and melanocyte-stimulating hormones. In addition to the typical clinical manifestations of functional pituitary tumors caused by excessive hormone levels, some pituitary tumors are also accompanied by abnormal glucose metabolism. The effects of these seven hormones on glucose metabolism are important for the treatment of diabetes secondary to pituitary tumors. This review focuses on the effects of hormones on glucose metabolism, providing important clues for the diagnosis and treatment of related diseases.

Suppression of Lipopolysaccharide-Induced IL-1β Gene Expression by High-Molecular-Weight Adiponectin in RAW264.7 Macrophages

Adiponectin is an abundant adipocytokine secreted by adipocytes. It exists in the plasma in its trimeric, hexameric, high-molecular-weight (HMW), and globular (a proteolytic product) isoforms. Adiponectin's anti-inflammatory effects on macrophages remain controversial. We have previously reported a simple and effective method for purifying native HMW adiponectin from human plasma. Here, we investigated whether native HMW adiponectin from human plasma has anti-inflammatory effects on macrophages. Pretreatment with human native HMW adiponectin inhibited lipopolysaccharide (LPS)-induced interleukin-1β (IL-1β) gene expression, but not tumor necrosis factor (TNF)-α expression. However, simultaneous treatment with HMW adiponectin and LPS did not inhibit IL-1β expression. Further, HMW adiponectin pretreatment decreases glycogen synthase kinase-3β (GSK-3β) inactivation by abrogating LPS-induced Akt (Ser473) phosphorylation, which subsequently suppresses LPS-induced CCAAT/enhancer binding protein β (C/EBPβ) protein translation and nuclear translocation. However, HMW adiponectin pretreatment did not affect LPS-induced nuclear factor-kappaB (NF-κB) activation. These results suggest that HMW adiponectin mediates potent anti-inflammatory activities in macrophages by inhibiting its Akt-C/EBPβ signaling pathway, thereby suppressing IL-1β gene expression.

Monocyte Chemoattractant Protein-1-Supplemented Plasma Enhances Adiponectin and Adipogenesis-Related Gene Expression

Increasing adipogenesis has been explored to treat metabolic diseases and atherosclerosis through the release of adiponectin. The effects and mechanism of platelet-rich plasma treatment on fat graft survival and adipogenesis have not been clarified. Here, we aimed to study the effects of monocyte chemoattractant protein-1 (MCP-1)-supplemented plasma on adipogenesis-related gene expression and adiponectin levels. Stromal vascular fractions (SVFs) purified from the inguinal adipose tissue of obese and diabetic (Lepr^db/db) mice were treated with plasma from control (Lepr^+/+) mice supplemented with 10 or 50 ng of MCP-1. The expression of adiponectin and interleukin-33 (IL-33) mRNA in adipose tissue was increased in Lepr^db/db mice, whereas control (Lepr^+/+) plasma reduced expression of IL-33 mRNA as well as peroxisome proliferator-activated receptor gamma (PPARγ), pJNK, and pNF-κB protein, and increased the expression of IL-10 mRNA in SVFs of Lepr^db/db mice. MCP-1-supplemented control plasma increased the expression of adiponectin, CCAAT-enhancer-binding protein α (C/EBPα), dipeptidyl peptidase 4 (DPP4), IL-33, and PDGFα mRNA and the expression of adiponectin protein as well as PPARγ of SVFs and the expression of PPARγ mRNA in adipose tissue macrophages (ATMs). Injection of MCP-1-supplemented plasma into adipose tissue of Lepr^db/db mice increased the expression of IL-33 and Col3a1 mRNA in SVFs and IL-33, FABP4, PDGFα, PPARγ and PPARγ2 of ATMs, protein expression of adiponectin and PPARγ of SVFs, and plasma adiponectin levels, as well as DPP4 activity. In conclusion, our results demonstrate that control plasma decreases adipogenesis and increases IL-10, and decreases IL-33, pJNK, and pNF-κB in adipose tissue. MCP-1-supplemented plasma enhances adipogenesis-related gene expression in SVFs and adiponectin levels, which may be mediated through an increase of IL-33 and PPARγ. Thus, our findings suggest that MCP-1-supplemented plasma represents a novel therapy to stimulate local adipogenesis and systemic adiponectin levels.

Thrombin-Mediated Formation of Globular Adiponectin Promotes an Increase in Adipose Tissue Mass

A decrease in the circulating levels of adiponectin in obesity increases the risk of metabolic complications, but the role of globular adiponectin, a truncated form produced by proteolytic cleavage, has not been defined. The objective of this investigation was to determine how globular adiponectin is generated and to determine whether this process impacts obesity. The cleavage of recombinant full-length adiponectin into globular adiponectin by plasma in vitro was used to identify Gly-93 as the N-terminal residue after proteolytic processing. The amino acid sequence of the cleavage site suggested thrombin was the protease responsible for cleavage, and inhibitors confirmed its likely involvement. The proteolytic site was modified, and this thrombin-resistant mutant protein was infused for 4 weeks into obese adiponectin-knockout mice that had been on a high-fat diet for 8 weeks. The mutation of the cleavage site ensured that globular adiponectin was not generated, and thus did not confound the actions of the full-length adiponectin. Mice infused with the mutant adiponectin accumulated less fat and had smaller adipocytes compared to mice treated with globular adiponectin, and concurrently had elevated fasting glucose. The data demonstrate that generation of globular adiponectin through the action of thrombin increases both adipose tissue mass and adipocyte size, but it has no effect on fasting glucose levels in the context of obesity.

A 60-Day Green Tea Extract Supplementation Counteracts the Dysfunction of Adipose Tissue in Overweight Post-Menopausal and Class I Obese Women

Menopause is characterized by weight gain and increased visceral fat, which acts as an endocrine organ secreting proinflammatory adipocytokines, with consequent increased risk of metabolic disorders. The aim of this double-blind, placebo-controlled randomized trial was to evaluate the effects of a 60-day dietary supplementation using Camellia sinensis leaf extract on adipose tissue dysfunction in overweight or class I obese post-menopausal, sedentary women. Primary endpoints were the respiratory quotient (RQ), the percentage of carbohydrates (%CHO), the percentage of fat oxidation (%FAT), and the resting energy expenditure (REE) measured by indirect calorimetry. Secondary endpoints included body composition, by dual x-ray absorptiometry (DXA), glucose profile, lipid profile, inflammatory state, liver and kidney function, hormonal status regarding satiety, and status of catecholamines. Twenty-eight women were randomized into two groups: 14 (BMI 31.1 ± 3.5) were supplemented and 14 (BMI 31.9 ± 2.2) received placebo. In regards to the between-group differences over time (β), a statistically significant difference between the supplemented and placebo group was observed for: RQ (β = -0.04, p = 0.009), % fat oxidation (β = 11.04, p = 0.0006), insulin (β = -1.74, p = 0.009), HOMA (β = -0.31, p = 0.02), waist circumference (β = -1.07, p = 0.007), REE (β = 83.21, p = 0.009), and CRP (β = -0.14, p = 0.02). These results demonstrate that a 60-day green tea extract supplementation counteracts the dysfunction of adipose tissue in overweight post-menopausal and class I obese women.

Brown adipose tissue influences adiponectin and thyroid hormone changes during Graves' disease therapy

Thyroid hormones (TH), adiponectin and brown adipose tissue (BAT) are regulators of energy homoeostasis. Influence of BAT activity on the relationship between TH and adiponectin remains unexplored. The aim of the study was to identify the relationship between TH and adiponectin and to clarify the impact of active BAT on the metabolic effects of adiponectin before and after the correction of thyrotoxicosis. Twenty-one patients with newly diagnosed hyperthyroidism from Graves' disease were recruited. A titration dosing regimen of thionamide anti-thyroid drug (ATD) was used to establish euthyroidism over 12-24 weeks. Anthropometric, biochemical and adipocytokine parameters were measured before and after control of hyperthyroidism. BAT activity was quantified by fusion 18 F-fluorodeoxyglucose (18 F-FDG) PET/MR imaging, and patients were grouped based on BAT status. Plasma adiponectin level was significantly increased following correction of hyperthyroidism in the overall sample. Free thyroxine (FT4) was also identified as a predictor of adiponectin level in thyroid dysfunction. However, significant changes in adiponectin level and correlations involving adiponectin were absent in BAT-positive patients but maintained in BAT-negative patients. BAT activity diminishes the correlative relationship with body composition and abolishes TH and adiponectin relationships when transitioning from a hyperthyroid to euthyroid state.

The effect of evening primrose oil (Oenothera biennis) on the level of adiponectin and some biochemical parameters in rats with fructose induced metabolic syndrome

The effect of evening primrose oil on adiponectin level and some biochemical parameters in model of fructose-induced metabolic syndrome were investigated. The rats were divided into 4 groups: control, evening primrose oil, fructose, fructose + evening primrose oil. Body weight, daily feed and water consumptions and systolic blood pressures of animals were measured. At the end of trial, blood samples were taken, livers were excised and histopathological examination was performed. Glucose, uric acid, triglyceride, T.cholesterol, LDL, HDL, VLDL, ALT, AST, ALP, LDH, adiponectin, insulin, IL-6, TNF-α, TAC, and TOS levels were analysed. Some analysed parameters and systolic blood pressure of fructose + evening primrose oil group decreased significantly compared to fructose group and adiponectin, TAC, and HDL levels were significantly increased. As conclusion, evening primrose oil can be considered as antioxidant agent by reducing oxidative stress, increasing adiponectin levels and insulin sensitivity, anti-inflammatory properties, exhibiting anti-atherogenic effect by regulating dyslipidemia and systolic blood pressure.

The Role of Adipokines in Inflammatory Mechanisms of Obesity

Adipokines are currently widely studied cellular signaling proteins produced by adipose tissue and involved in various processes, including inflammation; energy and appetite modulation; lipid and glucose metabolism; insulin sensitivity; endothelial cell functioning; angiogenesis; the regulation of blood pressure; and hemostasis. The current review attempted to highlight the key functions of adipokines in the inflammatory mechanisms of obesity, its complications, and its associated diseases. An extensive search for materials on the role of adipokines in the pathogenesis of obesity was conducted online using the PubMed and Scopus databases until October 2022.

Obesity, inflammation, and cancer in dogs: Review and perspectives

Obesity is the most common nutritional disease in dogs, and its prevalence has increased in recent decades. Several countries have demonstrated a prevalence of obesity in dogs similar to that observed in humans. Chronic low-grade inflammation is a prominent basis used to explain how obesity results in numerous negative health consequences. This is well known and understood, and recent studies have pointed to the association between obesity and predisposition to specific types of cancers and their complications. Such elucidations are important because, like obesity, the prevalence of cancer in dogs has increased in recent decades, establishing cancer as a significant cause of death for these animals. In the same way, intensive advances in technology in the field of human and veterinary medicine (which even proposes the use of animal models) have optimized existing therapeutic methods, led to the development of innovative treatments, and shortened the time to diagnosis of cancer. Despite the great challenges, this review aims to highlight the evidence obtained to date on the association between obesity, inflammation, and cancer in dogs, and the possible pathophysiological mechanisms that link obesity and carcinogenesis. The potential to control cancer in animals using existing knowledge is also presented.

Ginsenoside CK Inhibits the Early Stage of Adipogenesis via the AMPK, MAPK, and AKT Signaling Pathways

Obesity is considered a health hazard in part due to the associated multiple diseases. As rates of obesity continue to increase, a new strategy for its prevention and treatment is required. Compound-K, an active ingredient in ginseng, possesses antioxidant, anti-inflammatory, and anti-cancer properties. Although ginseng has used as various therapeutics, its potential ability to alleviate metabolic diseases by regulating adipocyte differentiation is still unknown. In this study, we found that CK treatment significantly inhibited lipid droplet and adipogenesis by downregulating the mRNA expression of C/ebpα, Ppar-γ, Fabp4, Srebp1, and adiponectin as well as protein levels of C/EBPα, PPAR-γ, and FABP4. CK also decreased the production of reactive oxygen species (ROS), while it increased endogeneous antioxidant enzymes such as catalase, glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD) 3 and SOD2. We observed that CK treatment suppressed the expression of cyclin-dependent kinase 1 (CDK1) and cyclin B1 during the mitotic clonal expansion (MCE) of adipocyte differentiation, and it arrested adipocytes at the G2/M stage due to the increased expression of p21 and p27. CK decreased the phosphorylation of extracellular signal-regulated kinase (ERK) and p38 and protein kinase B (AKT) in early-stage adipogenesis. In addition, the inhibition of adipogenesis by CK significantly increased the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC). Interestingly, AMPK pharmacological inhibition with Dorsomorphin limited the effect of CK on suppressing PPAR-γ expression in differentiated 3T3-L1 cells. Our results suggest that CK exerts anti-adipogenic effects in 3T3-L1 cells through the activation of AMPK and inhibition of ERK/p38 and AKT signaling pathways.

Pancreatic Islets as a Target of Adipokines

Rising rates of obesity are intricately tied to the type 2 diabetes epidemic. The adipose tissues can play a central role in protection against or triggering metabolic diseases through the secretion of adipokines. Many adipokines may improve peripheral insulin sensitivity through a variety of mechanisms, thereby indirectly reducing the strain on beta cells and thus improving their viability and functionality. Such effects will not be the focus of this article. Rather, we will focus on adipocyte-secreted molecules that have a direct effect on pancreatic islets. By their nature, adipokines represent potential druggable targets that can reach the islets and improve beta-cell function or preserve beta cells in the face of metabolic stress. © 2022 American Physiological Society. Compr Physiol 12:1-27, 2022.

Blood and Urinary Biomarkers of Antipsychotic-Induced Metabolic Syndrome

Metabolic syndrome (MetS) is a clustering of at least three of the following five medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein (HDL). Antipsychotic (AP)-induced MetS (AIMetS) is the most common adverse drug reaction (ADR) of psychiatric pharmacotherapy. Herein, we review the results of studies of blood (serum and plasma) and urinary biomarkers as predictors of AIMetS in patients with schizophrenia (Sch). We reviewed 1440 studies examining 38 blood and 19 urinary metabolic biomarkers, including urinary indicators involved in the development of AIMetS. Among the results, only positive associations were revealed. However, at present, it should be recognized that there is no consensus on the role of any particular urinary biomarker of AIMetS. Evaluation of urinary biomarkers of the development of MetS and AIMetS, as one of the most common concomitant pathological conditions in the treatment of patients with psychiatric disorders, may provide a key to the development of strategies for personalized prevention and treatment of the condition, which is considered a complication of AP therapy for Sch in clinical practice.

Adiponectin: friend or foe in obesity and inflammation

Adiponectin is an adipokine predominantly produced by fat cells, circulates and exerts insulin-sensitizing, cardioprotective and anti-inflammatory effects. Dysregulation of adiponectin and/or adiponectin signaling is implicated in a number of metabolic diseases such as obesity, insulin resistance, diabetes, and cardiovascular diseases. However, while the insulin-sensitizing and cardioprotective effects of adiponectin have been widely appreciated in the field, the obesogenic and anti-inflammatory effects of adiponectin are still of much debate. Understanding the physiological function of adiponectin is critical for adiponectin-based therapeutics for the treatment of metabolic diseases.

The transported active mulberry leaf phenolics inhibited adipogenesis through PPAR-γ and Leptin signaling pathway

The effective components of mulberry leaf polyphenols (MLPs) should be absorbed and transported by the intestinal cells before regulating lipid metabolism. The Caco-2 intestinal epithelial cell and 3 T3-L1 adipocytes were coupled to screen the effective components of MLPs that are being absorbed and transported by intestinal cells. The regulation and molecular mechanism by which the effective components affect adipogenesis were analyzed in this study. Among the 12 main components identified, five main compounds were well absorbed with Papp in the order of benzoic acid > chlorogenic acid > astragaloside > hyperoside > rutin. Chlorogenic acid and benzoic acid were mainly absorbed through passive diffusion, while rutin, astragaloside, and hyperoside were mainly by active transport, of which chlorogenic and rutin absorption were mediated by the efflux protein, P-glycoprotein (P-pg). Based on the transport volume of 2 mg/ml MLPs within 2 h, 25% of the maximum transported MLPs (TMLPs) was a safe concentration for 3 T3-L1 preadipocytes. Except for astragaloside, the other four components showed a significant inhibitory effect on lipid droplets, TG and TC, and chlorogenic acid and benzoic acid had the strongest effect. Additionally, we observed a synergistic effect as TMLPs were the most effective. We hypothesized that TMLPs, chlorogenic acid and benzoic acid suppressed adipogenesis and regulated lipid metabolism by inhibiting PPAR-γ, C/EBP-α, and FAS mRNA while promoting ADIPO and Leptin mRNA expression. PRACTICAL APPLICATIONS: The absorption and adipogenesis inhibition effect of mulberry leaf phenolics were evaluated in this study. The results provided guideline for the development of functional foods in regulating lipid metabolism.

New Insights into Adipokines in Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is the most common metabolic disorder of pregnancy and has considerable short- and long-term consequences for the health of both the mother and the newborn. Within its pathophysiology, genetic, nutritional, epigenetic, immunological, and hormonal components have been described. Within the last two items, it is known that different hormones and cytokines secreted by adipose tissue, known collectively as adipokines, are involved in the metabolic alterations underlying GDM. Although the maternal circulating profile of adipokines in GDM has been extensively studied, and there are excellent reviews on the subject, it is in recent years that more progress has been made in the study of their expression in visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), placenta, and their concentrations in the umbilical circulation. Thus, this review compiles and organizes the most recent findings on the maternal and umbilical circulating profile and the levels of expression of adipokines in VAT, SAT, and placenta in GDM.

Adiponectin receptors sustain haematopoietic stem cells throughout adulthood by protecting them from inflammation

How are haematopoietic stem cells (HSCs) protected from inflammation, which increases with age and can deplete HSCs? Adiponectin, an anti-inflammatory factor that is not required for HSC function or haematopoiesis, promotes stem/progenitor cell proliferation after bacterial infection and myeloablation. Adiponectin binds two receptors, AdipoR1 and AdipoR2, which have ceramidase activity that increases upon adiponectin binding. Here we found that adiponectin receptors are non-cell-autonomously required in haematopoietic cells to promote HSC quiescence and self-renewal. Adiponectin receptor signalling suppresses inflammatory cytokine expression by myeloid cells and T cells, including interferon-γ and tumour necrosis factor. Without adiponectin receptors, the levels of these factors increase, chronically activating HSCs, reducing their self-renewal potential and depleting them during ageing. Pathogen infection accelerates this loss of HSC self-renewal potential. Blocking interferon-γ or tumour necrosis factor signalling partially rescues these effects. Adiponectin receptors are thus required in immune cells to sustain HSC quiescence and to prevent premature HSC depletion by reducing inflammation.