Adiponectin and energy homeostasis

The role of adiponectin and its receptor signaling in ocular inflammation-associated diseases

Ocular inflammation-associated diseases are leading causes of global visual impairment, with limited treatment options. Adiponectin, a hormone primarily secreted by adipose tissue, binds to its receptors, which are widely distributed throughout the body, exerting powerful physiological regulatory effects. The protective role of adiponectin in various inflammatory diseases has gained increasing attention in recent years. Previous studies have confirmed the presence of adiponectin and its receptors in the eyes. Furthermore, adiponectin and its analogs have shown potential as novel drugs for the treatment of inflammatory eye diseases. This article summarizes the evidence for the interplay between adiponectin and inflammatory eye diseases and provides new perspectives on the diagnostic and therapeutic possibilities of adiponectin.

AdipoRon promotes amyloid-β clearance through enhancing autophagy via nuclear GAPDH-induced sirtuin 1 activation in Alzheimer's disease

BACKGROUND AND PURPOSE

Amyloid-β (Aβ) peptide is one of the more important pathological markers in Alzheimer's disease (AD). The development of AD impairs autophagy, which results in an imbalanced clearance of Aβ. Our previous research demonstrated that AdipoRon, an agonist of adiponectin receptors, decreased the deposition of Aβ and enhanced cognitive function in AD. However, the exact mechanisms by which AdipoRon affects Aβ clearance remain unclear.

EXPERIMENTAL APPROACH

We studied how AdipoRon affects autophagy in HT22 cells and APP/PS1 transgenic mice. We also investigated the signalling pathway involved and used pharmacological inhibitors to examine the role of autophagy in this process.

KEY RESULTS

AdipoRon promotes Aβ clearance by activating neuronal autophagy in the APP/PS1 transgenic mice. Interestingly, we found that AdipoRon induces the nuclear translocation of GAPDH, where it interacts with the SIRT1/DBC1 complex. This interaction then leads to the release of DBC1 and the activation of SIRT1, which in turn activates autophagy. Importantly, we found that inhibiting either GAPDH or SIRT1 to suppress the activity of SIRT1 counteracts the elevated autophagy and decreased Aβ deposition caused by AdipoRon. This suggests that SIRT1 plays a critical role in the effect of AdipoRon on autophagic induction in AD.

CONCLUSION AND IMPLICATIONS

AdipoRon promotes the clearance of Aβ by enhancing autophagy through the AdipoR1/AMPK-dependent nuclear translocation of GAPDH and subsequent activation of SIRT1. This novel molecular pathway sheds light on the modulation of autophagy in AD and may lead to the development of new therapeutic strategies targeting this pathway.

Adiponectin - stratification biomarker in diastolic cardiac dysfunction

This study does not propose to elucidate how adiponectin secretion is regulated, but how its adiponectin concentration is an indicator of heart disease. About adiponectin, it is not known whether it is functionally an enzyme, or very likely a cytokine/chemokine/hormone, secreted by fat cells/adipocytes in the abdomen. Abdominal fat secretes 67 hormones, and all of which cause disease. For example, adiponectin generates diabetes and ischaemic heart disease via dyslipidemia. Based on clinical symptoms, electrocardiographic and echocardiographic parameters, a group of 208 patients with diastolic cardiac dysfunction with or without preserved systolic function, developed on a background of painful chronic ischaemic heart disease, stable angina on exertion, was constituted. The serum levels of adiponectin, total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides were measured. Using the identified values, it was appreciated whether adiponectin correlates with the type of any of the two conditions, so that it can be recognised as a diagnostic and risk stratification marker.

Adiponectin: A Promising Target for the Treatment of Diabetes and Its Complications

Diabetes mellitus, a chronic metabolic disorder characterized by hyperglycemia, presents a formidable global health challenge with its associated complications. Adiponectin, an adipocyte-derived hormone, has emerged as a significant player in glucose metabolism and insulin sensitivity. Beyond its metabolic effects, adiponectin exerts anti-inflammatory, anti-oxidative, and vasoprotective properties, making it an appealing therapeutic target for mitigating diabetic complications. The molecular mechanisms by which adiponectin impacts critical pathways implicated in diabetic nephropathy, retinopathy, neuropathy, and cardiovascular problems are thoroughly examined in this study. In addition, we explore possible treatment options for increasing adiponectin levels or improving its downstream signaling. The multifaceted protective roles of adiponectin in diabetic complications suggest its potential as a novel therapeutic avenue. However, further translational studies and clinical trials are warranted to fully harness the therapeutic potential of adiponectin in the management of diabetic complications. This review highlights adiponectin as a promising target for the treatment of diverse diabetic complications and encourages continued research in this pivotal area of diabetes therapeutics.

Linking Adiponectin and Its Receptors to Age-Related Macular Degeneration (AMD)

In recent years, there has been a captivating focus of interest in elucidating the intricate crosstalk between adiponectin (APN), a versatile fat-associated adipokine and ocular pathologies. Unveiling the intricate relationship between adipocytokine APN and its receptors (AdipoRs) with aging eye disorders has emerged as a fascinating frontier in medical research. This review article delves into this connection, illuminating the hidden influence of APN on retinal health. This comprehensive review critically examines the latest findings and breakthroughs that underscore the pivotal roles of APN/AdipoRs signaling in maintaining ocular homeostasis and protecting against eye ailments. Here, we meticulously explore the intriguing mechanisms by which APN protein influences retinal function and overall visual acuity. Drawing from an extensive array of cutting-edge studies, the article highlights APN's multifaceted functions, ranging from anti-inflammatory properties and oxidative stress reduction to angiogenic regulation within retinal and macula tissues. The involvement of APN/AdipoRs in mediating these effects opens up novel avenues for potential therapeutic interventions targeting prevalent aging eye conditions. Moreover, this review unravels the interplay between APN signaling pathways and age-related macular degeneration (AMD). The single-cell RNA-seq results validate the expression of both the receptor isoforms (AdipoR1/R2) in retinal cells. The transcriptomic analysis showed lower expression of AdipoR1/2 in dry AMD pathogenesis compared to healthy subjects. The inhibitory adiponectin peptide (APN1) demonstrated over 75% suppression of CNV, whereas the control peptide did not exert any inhibitory effect on choroidal neovascularization (CNV). The elucidation of these relationships fosters a deeper understanding of adipose tissue's profound influence on ocular health, presenting new prospects for personalized treatments and preventative measures. Because APN1 inhibits CNV and leakage, it can be used to treat human AMD, although the possibility to treat human AMD is in the early stage and more clinical research is needed. In conclusion, this review provides a captivating journey into the enthralling world of APN, intertwining the realms of adipose biology and ophthalmology in aging.

Goldfish adiponectin: (I) molecular cloning, tissue distribution, recombinant protein expression, and novel function as a satiety factor in fish model

Adiponectin (AdipoQ) is an adipokine involved in glucose homeostasis and lipid metabolism. In mammals, its role in appetite control is highly controversial. To shed light on the comparative aspects of AdipoQ in lower vertebrates, goldfish was used as a model to study feeding regulation by AdipoQ in fish species. As a first step, goldfish AdipoQ was cloned and found to be ubiquitously expressed at the tissue level. Using sequence alignment, protein modeling, phylogenetic analysis and comparative synteny, goldfish AdipoQ was shown to be evolutionarily related to its fish counterparts and structurally comparable with AdipoQ in higher vertebrates. In our study, recombinant goldfish AdipoQ was expressed in E. coli, purified by IMAC, and confirmed to be bioactive via activation of AdipoQ receptors expressed in HepG2 cells. Feeding in goldfish revealed that plasma levels of AdipoQ and its transcript expression in the liver and brain areas involved in appetite control including the telencephalon, optic tectum, and hypothalamus could be elevated by food intake. In parallel studies, IP and ICV injection of recombinant goldfish AdipoQ in goldfish was effective in reducing foraging behaviors and food consumption. Meanwhile, transcript expression of orexigenic factors (NPY, AgRP, orexin, and apelin) was suppressed with parallel rises in anorexigenic factors (POMC, CART, CCK, and MCH) in the telencephalon, optic tectum and/or hypothalamus. In these brain areas, transcript signals for leptin receptor were upregulated with concurrent drops in the NPY receptor and ghrelin receptors. In the experiment with IP injection of AdipoQ, transcript expression of leptin was also elevated with a parallel drop in ghrelin mRNA in the liver. These findings suggest that AdipoQ can act as a novel satiety factor in goldfish. In this case, AdipoQ signals (both central and peripheral) can be induced by feeding and act within the brain to inhibit feeding behaviors and food intake via differential regulation of orexigenic/anorexigenic factors and their receptors. The feeding inhibition observed may also involve the hepatic action of AdipoQ by modulation of feeding regulators expressed in the liver.

Sexual dimorphic metabolic and cognitive responses of C57BL/6 mice to Fisetin or Dasatinib and quercetin cocktail oral treatment

Senolytic treatment in aged mice clears senescent cell burden leading to functional improvements. However, less is known regarding the effects of these compounds when administered prior to significant senescent cell accumulation. From 4-13 months of age, C57BL/6 male and female mice received monthly oral dosing of either 100 mg/kg Fisetin or a 5 mg/kg Dasatinib (D) plus 50 mg/kg Quercetin (Q) cocktail. During treatment, several aspects of healthy aging were assayed including glucose metabolism using an insulin and glucose tolerance test, cognitive performance using Morris water maze and novel object recognition, and energy metabolism using indirect calorimetry. Afterwards, mice were euthanized for plasma, tissue specific markers of senescence-associated secretory phenotype (SASP), and white adipose tissue accumulation (WAT). Sexually dimorphic treatment effects were observed. Fisetin treated male mice had reduced SASP, enhanced glucose and energy metabolism, improved cognitive performance, and increased mRNA expression of adiponectin receptor 1 and glucose transporter 4. D + Q treatment had minimal effects in male C57BL/6 mice, but was detrimental to females causing increased SASP expression along with accumulation of WAT depots. Reduced energy metabolism and cognitive performance were also noted. Fisetin treatment had no effect in female C57BL/6 mice potentially due to a slower rate of biological aging. In summary, the senolytic treatment in young adulthood, has beneficial, negligible, or detrimental effects in C57BL/6 mice dependent upon sex and treatment. These observations should serve as a note of caution in this rapidly evolving and expanding field of investigation. Male and female C57BL/6 mice were treated with once monthly oral doses of either Dasatinib (D) + Quercetin (Q) or Fisetin from 4-13 months of age. Males treated with Fisetin had reduced SASP markers (blue spheres) as well as improved metabolism (red flame) and cognition. Females treated with D + Q had increased adiposity and SASP markers (red spheres) along with decreased metabolism (blue flame) and cognitive performance. No effects were observed in females treated with Fisetin or males treated with D + Q.

Plasma Adiponectin and Its Correlation with Carotid Intima-Media Thickness in Obesity and in Type 2 Diabetes and Nonalcoholic Fatty Liver Disease

Methods and Results

The study included 200 Egyptian subjects. They were divided into four equal groups: group 1: obese patients with NAFLD and T2DM (O+/NAFLD+/DM+), group 2: nonobese patients with NAFLD and T2DM (O-/NAFLD+/DM+), group 3: obese nondiabetic patients with NAFLD (O+/NAFLD+/DM-), and group 4: nonobese healthy control subjects. Plasma adiponectin was measured using ELISA (enzyme-linked immunosorbent assay) technique. Ultrasonography was used to diagnose NAFLD. CIMT was assessed using Doppler ultrasonography. Plasma adiponectin was significantly lower and CIMT was significantly higher in O+/NAFLD+/DM+, as compared with O-/NAFLD+/DM+, O+/NAFLD+/DM-, and control subjects (p < 0.001 for all). A significant negative correlation was found between adiponectin and CIMT in obese patients with NAFLD (p < 0.05), but not in patients with NAFLD and T2DM. The significant independent predictors of CIMT were diabetes duration, BMI (body mass index), albumin/creatinine ratio, and cholesterol.

Conclusion

Plasma adiponectin is inversely correlated with CIMT in obese patients with NAFLD, but not in patients with NAFLD and T2DM. Hypoadiponectinemia could be a good indicator of cardiovascular risk in obese patients with NAFLD, with or without T2DM, but not in nonobese patients with NAFLD.

Emerging Role of Adiponectin/AdipoRs Signaling in Choroidal Neovascularization, Age-Related Macular Degeneration, and Diabetic Retinopathy

Age-related macular degeneration (AMD), a leading cause of irreversible blindness in adults, may result in poor central vision, making it difficult to see, read, and drive. AMD is generally classified in either dry or wet types. Milder cases of dry AMD may progress to geographic atrophy (GA), leading to significant visual disability; wet, or neovascular AMD, which involves choroidal neovascularization (CNV), can lead to complete loss of central vision. Adiponectin (APN) discovery in the mid-1990's and, subsequently, its two cognate receptors (AdipoRs) in the early 2000s have led to a remarkable progress in better understanding metabolic disorders, as well as metabolism-associated ocular pathology. APN/AdipoRs signaling plays a central role in a variety of molecular and cellular physiological events, including glucose and lipid metabolism, whole-body energy regulation, immune and inflammation responses, insulin sensitivity and retinal cell biological functions. This review is an amalgamation of recent information related to APN/AdipoRs in the pathophysiology of retinal diseases and furthers its association with AMD and diabetic retinopathy. Additionally, we present our original research, where we designed control peptide and CNV inhibitory peptide from the globular region of APN to see the effect of these peptides on the mouse model of laser-induced CNV. The inhibitory peptide (APN1) inhibited CNV by more than 75% while the control peptide did not inhibit CNV.

Comparing the responses of grain fed feedlot cattle under moderate heat load and during subsequent recovery with those of feed restricted thermoneutral counterparts: metabolic hormones

We set out to determine the impact of moderate heat load on the plasma concentrations of a suite of hormones involved in regulating energy metabolism and feed intake. The responses of the thermally challenged (TC) feedlot steers were compared to those of feed restricted thermoneutral (FRTN) steers. Two sequential cohorts of twelve 518 ± 23 kg Black Angus steers on finisher grain ration were housed in climate-controlled rooms (CCR) for 18 days and returned to outdoor pens for 40 days. The TC group was subjected to a diurnal range of 28-35 °C for 7 days (Challenge) but held in thermoneutral conditions beforehand (PreChallenge), and in Recovery (after Challenge). The FRTN group was held in thermoneutral conditions and feed restricted throughout. Blood was collected over the three periods in CCR and two periods in outdoor pens for 40 days (PENS and Late PENS). Plasma concentrations of prolactin, thyroid stimulating hormone, insulin, leptin, adiponectin and thyroxine (T4) were determined during the five periods. Whilst the pituitary hormones were relatively stable, there were differences in plasma leptin, adiponectin and T4 between the two groups during Challenge and Recovery, and occasionally in PENS. The interaction of the plasma hormone concentrations and rumen temperature and DMI were also investigated. Whilst the positive relationship between DMI and leptin was confirmed, we found a strong negative relationship between adiponectin and rumen temperature, and a strong positive relationship between adiponectin and dry matter intake (DMI) in the TC steers only.

Hormonal regulation of visfatin and adiponectin system in quail muscle cells

Visfatin and adiponectin are two adipokines known to regulate energy homeostasis and stress response within different peripheral tissues. Their role and regulation in highly metabolically active tissue such as the muscle is of particular interest. As modern poultry exhibit insulin resistance, obesity, and hyperglycemia along with a lack of insight into the regulation of these avian adipokines, we undertook the present work to determine the regulation of visfatin and adiponectin system by cytokines and obesity-related hormones in a relevant in vitro model of avian muscle, quail muscle (QM7) cells. Cells were treated with pro-inflammatory cytokine IL-6 (5 and 10 ng/mL) and TNFα (5 and 10 ng/mL), as well as leptin (10 and 100 ng/mL) and both orexin-A and orexin-B (ORX-A/B) (5 and 10 ng/mL). Results showed significant increases in visfatin mRNA abundance under both cytokines (IL-6 and TNFα), and down regulation with ORX-B treatment. Adiponectin expression was also upregulated by pro-inflammatory cytokines (IL-6 and TNFα), but down regulated by leptin, ORX-A, and ORXB. High doses of IL-6 and TNFα up regulated the expression of adiponectin receptors AdipoR1 and AdipoR2, respectively. Leptin and orexin treatments also down regulated both AdipoR1 and AdipoR2 expression. Taken together, this is the first report showing a direct response of visfatin and the adiponectin system to pro-inflammatory and obesity-related hormones in avian muscle cells.

Diminished AdipoR1/APPL1 Interaction Mediates Reduced Cardioprotective Actions of Adiponectin against Myocardial Ischemia/Reperfusion Injury in Type-2 Diabetic Mice

Background

Obesity-related diseases have important implications for the occurrence, severity, and outcome of ischemic heart disease. Patients with obesity, hyperlipidemia, and diabetes mellitus (metabolic syndrome) are at increased risk of heart attack with decreased plasma lipocalin levels, and lipocalin is negatively correlated with heart attack incidence. APPL1 is a signaling protein with multiple functional structural domains and plays an important role in the APN signaling pathway. There are two known subtypes of lipocalin membrane receptors, AdipoR1 and AdipoR2. AdioR1 is mainly distributed in skeletal muscle while AdipoR2 is mainly distributed in the liver.

Objective

To clarify whether the AdipoR1-APPL1 signaling pathway mediates the effect of lipocalin in reducing myocardial ischemia/reperfusion injury and its mechanism will provide us with a new approach to treat myocardial ischemia/reperfusion injury using lipocalin as an intervention and therapeutic target.

Methods

(1) Induction of hypoxia/reoxygenation in SD mammary rat cardiomyocytes to simulate myocardial ischemia/reperfusion; (2) downregulation of APPL1 expression in cardiomyocytes to observe the effect of lipocalin on myocardial ischemia/reperfusion and its mechanism of action.

Results

(1) Primary mammary rat cardiomyocytes were isolated and cultured and induced to simulate MI/R by hypoxia/reoxygenation; (2) lipocalin inhibited H/R-induced apoptosis in cardiomyocytes; and (3) APN attenuated MI/R injury through AdipoR1-APPL1 and the possible mechanism.

Conclusion

This study demonstrates for the first time that lipocalin can attenuate myocardial ischemia/reperfusion injury through the AdipoR1-APPL1 signaling pathway and that the reduction of AdipoR1/APPL1 interaction plays an important role in cardiac APN resistance to MI/R injury in diabetic mice.

Comparing the effects of retro and forward walking on serum adiponectin levels in obese young adults

Objectives

Retro walking or backward walking expends greater energy and places less stress on joints compared with forward walking at a similar speed. This study conducted in obese young men was primarily aimed at comparing the effects of backward walking with forward walking on adiponectin levels. The secondary aim was to describe the effects of concomitant factors, namely C-reactive protein, body mass index (BMI), waist to height ratio, and waist to hip ratio, on adiponectin levels in obese young men.

Methods

In this randomized comparative study, 102 participants underwent either retro walking or forward walking treadmill training four times a week for 12 weeks before and after which adiponectin, C-reactive protein, BMI, waist to height ratio, and waist to hip ratio were measured. Comparison of the measured values before and after intervention and between the groups was done, and the influence of C-reactive protein, BMI, waist to height ratio, and waist to hip ratio on adiponectin levels was determined.

Results

Adiponectin levels were significantly increased (p < 0.001) and C-reactive protein, BMI, waist to height ratio, and waist to hip ratio were significantly decreased (p ≤ 0.001) post-intervention. The participants who underwent retro walking training showed a significantly higher change in C-reactive protein levels, BMI, and waist to hip ratio compared to the forward walking group (p < 0.001). Adiponectin levels were influenced by BMI (p < 0.001).

Conclusion

Retro walking training leads to a greater increase in adiponectin and reduction in C-reactive protein, BMI, waist to height ratio, and waist to hip ratio compared to forward walking, and adiponectin levels are influenced by BMI. Retro walking treadmill training can be preferentially used to decrease cardiovascular risk factors.

Levels of hormones regulating appetite and energy homeostasis in response to a 1.5-Year combined lifestyle intervention for obesity

Background: Weight loss can induce changes in appetite-regulating hormone levels, possibly linked to increases in appetite and weight regain. However, hormonal changes vary across interventions. Here, we studied levels of appetite-regulating hormones during a combined lifestyle intervention (CLI: healthy diet, exercise and cognitive behavioral therapy). Methods: We measured levels of long-term adiposity-related hormones (leptin, insulin, high-molecular-weight (HMW) adiponectin) and short-term appetite hormones (PYY, cholecystokinin, gastric-inhibitory polypeptide, pancreatic polypeptide, FGF21, AgRP) in overnight-fasted serum of 39 patients with obesity. Hormone levels were compared between T0 (baseline), T1 (after 10 weeks) and T2 (end of treatment, 1.5 years). T0-T1 hormone changes were correlated with T1-T2 anthropometric changes. Results: Initial weight loss at T1 was maintained at T2 (-5.0%, p < 0.001), and accompanied by decreased leptin and insulin levels at T1 and T2 (all p < 0.05) compared to T0. Most short-term signals were not affected. Only PP levels were decreased at T2 compared to T0 (p < 0.05). Most changes in hormone levels during initial weight loss did not predict subsequent changes in anthropometrics, except for T0-T1 decreases in FGF21 levels and T0-T1 increases in HMW adiponectin levels tended to be associated with larger T1-T2 increases in BMI (p < 0.05 and p = 0.05, respectively). Conclusion: CLI-induced weight loss was associated with changes in levels of long-term adiposity-related hormones towards healthy levels, but not with orexigenic changes in most short-term appetite signals. Our data indicates that the clinical impact of alterations in appetite-regulating hormones during modest weight loss remains questionable. Future studies should investigate potential associations of weight-loss-induced changes in FGF21 and adiponectin levels with weight regain.

Cysteine restriction-specific effects of sulfur amino acid restriction on lipid metabolism

Decreasing the dietary intake of methionine exerts robust anti-adiposity effects in rodents but modest effects in humans. Since cysteine can be synthesized from methionine, animal diets are formulated by decreasing methionine and eliminating cysteine. Such diets exert both methionine restriction (MR) and cysteine restriction (CR), that is, sulfur amino acid restriction (SAAR). Contrarily, SAAR diets formulated for human consumption included cysteine, and thus might have exerted only MR. Epidemiological studies positively correlate body adiposity with plasma cysteine but not methionine, suggesting that CR, but not MR, is responsible for the anti-adiposity effects of SAAR. Whether this is true, and, if so, the underlying mechanisms are unknown. Using methionine- and cysteine-titrated diets, we demonstrate that the anti-adiposity effects of SAAR are due to CR. Data indicate that CR increases serinogenesis (serine biosynthesis from non-glucose substrates) by diverting substrates from glyceroneogenesis, which is essential for fatty acid reesterification and triglyceride synthesis. Molecular data suggest that CR depletes hepatic glutathione and induces Nrf2 and its downstream targets Phgdh (the serine biosynthetic enzyme) and Pepck-M. In mice, the magnitude of SAAR-induced changes in molecular markers depended on dietary fat concentration (60% fat >10% fat), sex (males > females), and age-at-onset (young > adult). Our findings are translationally relevant as we found negative and positive correlations of plasma serine and cysteine, respectively, with triglycerides and metabolic syndrome criteria in a cross-sectional epidemiological study. Controlled feeding of low-SAA, high-polyunsaturated fatty acid diets increased plasma serine in humans. Serinogenesis might be a target for treating hypertriglyceridemia.

Obesity: A Doorway to a Molecular Path Leading to Infertility

The dramatic rise in obesity has recently made it a global health issue. About 1.9 billion were overweight, and 650 million global populations were obese in 2016. Obese women suffer longer conception time, lowered fertility rates, and greater rates of miscarriage. Obesity alters hormones such as adiponectin and leptin, affecting all levels within the hypothalamic-pituitary-gonadal axis. Advanced glycation end products (AGEs) and monocyte chemotactic protein-1 (MCP-1) are inflammatory cytokines that may play an important role in the pathophysiology of ovarian dysfunction in obesity. In obese males, there are altered sperm parameters, reduced testosterone, increased estradiol, hypogonadism, and epigenetic modifications transmitted to offspring. The focus of this article is on the possible adverse effects on reproductive health resulting from obesity and sheds light on different molecular pathways linking obesity with infertility in both female and male subjects. Electronic databases such as Google Scholar, Embase, Science Direct, PubMed, and Google Search Engine were utilized to find obesity and infertility-related papers. The search strategy is detailed in the method section. Even though multiple research work has shown that obesity impacts fertility in both male and female negatively, it is significant to perform extensive research on the molecular mechanisms that link obesity to infertility. This is to find therapeutics that may be developed aiming at these mechanisms to manage and prevent the negative effects of obesity on the reproductive system.

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.

Leptin and adiponectin regulate the activity of nuclei involved in sleep-wake cycle in male rats

Epidemiological and experimental evidence recognize a relationship between sleep-wake cycles and adiposity levels, but the mechanisms that link both are not entirely understood. Adipose tissue secretes adiponectin and leptin hormones, mainly involved as indicators of adiposity levels and recently associated to sleep. To understand how two of the main adipose tissue hormones could influence sleep-wake regulation, we evaluated in male rats, the effect of direct administration of adiponectin or leptin in the ventrolateral preoptic nuclei (VLPO), a major area for sleep promotion. The presence of adiponectin (AdipoR1 and AdipoR2) and leptin receptors in VLPO were confirmed by immunohistochemistry. Adiponectin administration increased wakefulness during the rest phase, reduced delta power, and activated wake-promoting neurons, such as the locus coeruleus (LC), tuberomammillary nucleus (TMN) and hypocretin/orexin neurons (OX) within the lateral hypothalamus (LH) and perifornical area (PeF). Conversely, leptin promoted REM and NREM sleep, including increase of delta power during NREM sleep, and induced c-Fos expression in VLPO and melanin concentrating hormone expressing neurons (MCH). In addition, a reduction in wake-promoting neurons activity was found in the TMN, lateral hypothalamus (LH) and perifornical area (PeF), including in the OX neurons. Moreover, leptin administration reduced tyrosine hydroxylase (TH) immunoreactivity in the LC. Our data suggest that adiponectin and leptin act as hormonal mediators between the status of body energy and the regulation of the sleep-wake cycle.

Adiponectin Deficiency Alters Placenta Function but Does Not Affect Fetal Growth in Mice

Adiponectin administration to pregnant mice decreases nutrient transport and fetal growth. An adiponectin deficiency, on the other hand, as seen in obese women during pregnancy, alters fetal growth; however, the mechanism is unclear. To determine the role of adiponectin on placenta function and fetal growth, we used adiponectin knockout, adiponectin heterozygote that displays reduced adiponectin levels, and wild-type mice on a control diet or high fat/high sucrose (HF/HS) diet. Triglycerides (TGs) in the serum, liver, and placenta were measured using colorimetric assays. Gene expression was measured using quantitative RT-PCR. Adiponectin levels did not affect fetal weight, but it reduced adiponectin levels, increased fetal serum and placenta TG content. Wildtype dams on a HF/HS diet protected the fetuses from fatty acid overload as judged by increased liver TGs in dams and normal serum and liver TG levels in fetuses, while low adiponectin was associated with increased fetal liver TGs. Low maternal adiponectin increased the expression of genes involved in fatty acid transport; Lpl and Cd36 in the placenta. Adiponectin deficiency does not affect fetal growth but induces placental dysfunction and increases fetal TG load, which is enhanced with obesity. This could lead to imprinting effects on the fetus and the development of metabolic dysfunction in the offspring.

Adiponectin inhibits the activation of lung fibroblasts and pulmonary fibrosis by regulating the nuclear factor kappa B (NF-κB) pathway

Idiopathic pulmonary fibrosis (IPF) is a common pulmonary interstitial disease with a high mortality rate. Adiponectin (APN) is reportedly an effective therapy for fibrosis-related diseases. This study aimed to investigate the potential effects of APN on IPF. Male BALB/c mice were injected with bleomycin (BLM) and treated with different doses of APN (0.1, 0.25, and 0.5 mg/kg). The body weights of the mice were recorded. Immunohistochemical, hematoxylin and eosin, and Masson staining were performed to evaluate pulmonary histopathological changes. Enzyme-linked immunosorbent assay (ELISA) and western blotting were performed to assess tissue inflammation. The human lung fibroblasts HELF were stimulated with TGF-β1 and treated with different doses of APN (2.5, 5, and 10 μg/ml). Cell proliferation, inflammation, and fibrosis were determined by MTT assay, EdU assay, colony formation assay, ELISA, and western blotting. APN significantly attenuated BLM-induced body weight loss, alveolar destruction, and collagen fiber accumulation in mice (p < 0.05). APN decreased the expression of α-SMA and collagen I and reduced the concentration of TNF-α, IL-6, IL-1β, and IL-18 in lung tissues (p < 0.05). In TGF-β1-treated HELF cells, cell proliferation and colony formation were inhibited by APN (p < 0.05). Additionally, the expression of α-SMA, collagen I, and pro-inflammatory cytokines were suppressed by APN (p < 0.05). APN inhibited the phosphorylation of IκB and nuclear translocation of p65. In conclusion, these findings suggest that APN is an effective agent for controlling IPF progression. The antifibrotic effects of APN might be mediated via inhibiting the NF-κB signaling pathway.

Significance of Brain Glucose Hypometabolism, Altered Insulin Signal Transduction, and Insulin Resistance in Several Neurological Diseases

Several neurological diseases share pathological alterations, even though they differ in their etiology. Neuroinflammation, altered brain glucose metabolism, oxidative stress, mitochondrial dysfunction and amyloidosis are biological events found in those neurological disorders. Altered insulin-mediated signaling and brain glucose hypometabolism are characteristic signs observed in the brains of patients with certain neurological diseases, but also others such as type 2 diabetes mellitus and vascular diseases. Thus, significant reductions in insulin receptor autophosphorylation and Akt kinase activity, and increased GSK-3 activity and insulin resistance, have been reported in these neurological diseases as contributing to the decline in cognitive function. Supporting this relationship is the fact that nasal and hippocampal insulin administration has been found to improve cognitive function. Additionally, brain glucose hypometabolism precedes the unmistakable clinical manifestations of some of these diseases by years, which may become a useful early biomarker. Deficiencies in the major pathways of oxidative energy metabolism have been reported in patients with several of these neurological diseases, which supports the hypothesis of their metabolic background. This review remarks on the significance of insulin and brain glucose metabolism alterations as keystone common pathogenic substrates for certain neurological diseases, highlighting new potential targets.

Association of ADIPOQ-rs2241766 and FTO-rs9939609 genetic variants with body mass index trajectory in women of reproductive age over 6 years of follow-up: the PREDI study

BACKGROUND

Interindividual variations in body mass index (BMI) can be partially explained by genetic differences. We aimed to examine the association of the ADIPOQ-rs2241766, LEP-rs7799039 and FTO-rs9939609 genetic variants with BMI trajectory in women of reproductive age over 6 years of follow-up.

METHODS

This was a prospective study that used data from 435 women of the PREDI Study conducted in Brazil. Socioeconomic, biological and anthropometric data were collected at four time points: 2012 (baseline) in the maternity hospital, and 2013-14, 2016-17 and 2018 (1^st, 2^nd and 3^rd follow-ups) at the participant's home. Genotyping was performed by PCR-RFLP. Linear mixed-effect and Poisson regression models were used to address the association of ADIPOQ, LEP and FTO genotypes with BMI and overweight/obesity status.

RESULTS

Women carrying the risk allele (TA or AA) of the FTO-rs9939609 genetic variant had a 1.16 kg/m² higher BMI over the follow-up period than those carrying the wild-type genotype (TT), even when adjusted for potential confounders (95% CI: 0.23-2.10, p = 0.015). The risk of obesity associated with the FTO-TA or AA genotype decreased over the years, demonstrating an influence of time on its trajectory (IRR = 0.99, 95% CI: 0.98-0.99, p = 0.016). There was no variation in BMI trajectories for the ADIPOQ-rs2241766, LEP-rs7799039 or FTO-rs9939609 genetic variant.

CONCLUSIONS

The results of this study suggest that monitoring women of reproductive age with ADIPOQ-rs2241766 TG/GG or FTO-rs9939609 TA/AA genotypes may be an important strategy to reduce maternal excess body weight and, consequently, the long-term public health burden of obesity.

Fresh Mango Consumption Promotes Greater Satiety and Improves Postprandial Glucose and Insulin Responses in Healthy Overweight and Obese Adults

Mangos are an understudied fruit rich in fiber and polyphenols that have been linked to better metabolic outcomes and promotion of satiety. The purpose of this study was to examine the effect of mango consumption on postprandial glucose, insulin, and satiety responses. Using a randomized crossover study design, 23 overweight and obese men and women consumed 100 kcal snacks of fresh mangos or isocaloric low-fat cookies on two separate occasions. Insulin and satiety hormones were measured at baseline and 45 min post-snack consumption. Glucose was measured at baseline, 30, 60, 90, and 120 min after snack consumption. Satiety questionnaires were completed at baseline and every 20 min for 120 min post-consumption. Both mangos and low-fat cookies increased insulin, with a significantly lower increase for mangos compared with low-fat cookies at 45 min post-snack consumption (P ≤ .05). Glucose increased at 30 min for both snacks; however, the increase was significantly higher for low-fat cookie consumption (P ≤ .05). Cholecystokinin increased after mangos and low-fat cookie consumption (P ≤ .05); however, no differences were detected between the snacks. Adiponectin increased after mango consumption (P ≤ .05) but not after low-fat cookies. Mango consumption reduced hunger, anticipated food consumption and thirst, and increased feelings of fullness (P ≤ .05). Low-fat cookie consumption increased fullness for a shorter time period and did not reduce participants' desire to eat. These results suggest that relative to a refined cookie snack, mangos promote greater satiety and improve postprandial glycemic responses. Future research on long-term effects of mango consumption on food intake, weight control, and glucose homeostasis is warranted. Clinical Trial Registration number: #NCT03957928.

Anthocyanins: From Mechanisms of Regulation in Plants to Health Benefits in Foods

Anthocyanins represent the major red, purple, and blue pigments in many flowers, fruits, vegetables, and cereals. They are also recognized as important health-promoting components in the human diet with protective effects against many chronic diseases, including cardiovascular diseases, obesity, and cancer. Anthocyanin biosynthesis has been studied extensively, and both biosynthetic and key regulatory genes have been isolated in many plant species. Here, we will provide an overview of recent progress in understanding the anthocyanin biosynthetic pathway in plants, focusing on the transcription factors controlling activation or repression of anthocyanin accumulation in cereals and fruits of different plant species, with special emphasis on the differences in molecular mechanisms between monocot and dicot plants. Recently, new insight into the transcriptional regulation of the anthocyanin biosynthesis, including positive and negative feedback control as well as epigenetic and post-translational regulation of MYB-bHLH-WD40 complexes, has been gained. We will consider how knowledge of regulatory mechanisms has helped to produce anthocyanin-enriched foods through conventional breeding and metabolic engineering. Additionally, we will briefly discuss the biological activities of anthocyanins as components of the human diet and recent findings demonstrating the important health benefits of anthocyanin-rich foods against chronic diseases.

Sugars and Sweet Taste: Addictive or Rewarding?

The notion of food "addiction" often focuses on the overconsumption of sweet tasting foods or so-called sugar "addiction". In the extreme, some have suggested that sugar and sweet tastes elicit neural and behavioral responses analogous to those observed with drugs of abuse. These concepts are complicated by the decades long uncertainty surrounding the validity and reproducibility of functional magnetic resonance imaging (fMRI) methodologies used to characterize neurobiological pathways related to sugar and sweet taste stimuli. There are also questions of whether sweet taste or post-ingestion metabolic consequences of sugar intake would lead to addiction or excessive caloric intake. Here, we present a focused narrative review of literature related to the reward value of sweet taste which suggests that reward value can be confounded with the construct of "addictive potential". Our review seeks to clarify some key distinctions between these constructs and questions the applicability of the addiction construct to human over-eating behaviors. To adequately frame this broad discussion requires the flexibility offered by the narrative review paradigm. We present selected literature on: techniques used to link sugar and sweet tastes to addiction neurobiology and behaviors; sugar and sweet taste "addiction"; the relationship of low calorie sweetener (LCS) intake to addictive behaviors and total calorie intake. Finally, we examined the reward value of sweet tastes and contrasted that with the literature describing addiction. The lack of reproducibility of fMRI data remains problematic for attributing a common neurobiological pathway activation of drugs and foods as conclusive evidence for sugar or sweet taste "addiction". Moreover, the complicated hedonics of sweet taste and reward value are suggested by validated population-level data which demonstrate that the consumption of sweet taste in the absence of calories does not increase total caloric intake. We believe the neurobiologies of reward value and addiction to be distinct and disagree with application of the addiction model to sweet food overconsumption. Most hypotheses of sugar "addiction" attribute the hedonics of sweet foods as the equivalent of "addiction". Further, when addictive behaviors and biology are critically examined in totality, they contrast dramatically from those associated with the desire for sweet taste. Finally, the evidence is strong that responses to the palatability of sweets rather than their metabolic consequences are the salient features for reward value. Thus, given the complexity of the controls of food intake in humans, we question the usefulness of the "addiction" model in dissecting the causes and effects of sweet food over-consumption.

Adiponectin and Asthma: Knowns, Unknowns and Controversies

Adiponectin is an adipokine associated with the healthy obese phenotype. Adiponectin increases insulin sensitivity and has cardio and vascular protection actions. Studies related to adiponectin, a modulator of the innate and acquired immunity response, have suggested a role of this molecule in asthma. Studies based on various asthma animal models and on the key cells involved in the allergic response have provided important insights about this relation. Some of them indicated protection and others reversed the balance towards negative effects. Many of them described the cellular pathways activated by adiponectin, which are potentially beneficial for asthma prevention or for reduction in the risk of exacerbations. However, conclusive proofs about their efficiency still need to be provided. In this article, we will, briefly, present the general actions of adiponectin and the epidemiological studies supporting the relation with asthma. The main focus of the current review is on the mechanisms of adiponectin and the impact on the pathobiology of asthma. From this perspective, we will provide arguments for and against the positive influence of this molecule in asthma, also indicating the controversies and sketching out the potential directions of research to complete the picture.

Altered cardiometabolic profile in girls with central precocious puberty and adipokines: A propensity score matching analysis

OBJECTIVE

To compare cardiometabolic factors and adipokines between patients with recently diagnosed CPP and controls without CPP, paired by BMI Z scores (BMIz) and classified into girls with adequate nutritional status and girls who are overweight or obese.

METHODS

This cross-sectional study was performed from January 2012 to May 2015 at two tertiary care pediatric centers in Mexico City. We included female patients with idiopathic CPP without other chronic pathology and healthy controls. Patients were divided into groups, BMI < 85th and BMI ≥ 85th percentile, according to 2000 CDC Growth Charts. Anthropometric data and fasting plasma concentrations of lipids, glucose, insulin, and leptin were assessed.

RESULTS

There were 73 patients with CPP and 82 without CPP. Sixty-six patients were matched between the groups; no significant difference was noted between the groups according to zBMI. However, differences in the bone/chronological age relationship, birth weight and proportions in different Tanner stages were observed. Among girls with normal BMI, the percentage of body fat (24.6% vs 18.9%, p < 0.001), serum triglycerides (102.9 vs 54.3 mg/dl, p < 0.001), leptin (7.46 vs 5.4 ng/ml, p = 0.010) and free leptin (0.44 vs 0.29 ng/ml, p = 0.044) were higher in those with CPP; additionally, girls with CPP presented a higher proportion of hypertriglyceridemia. In the overweight/obese group, adiponectin levels were lower in girls with CPP (6.23 vs 7.28 pg/ml, p = 0.011).

CONCLUSIONS

Girls with CPP and normal BMI at diagnosis had a worse cardiometabolic profile, as reflected by higher levels of free leptin, and higher proportion of hypertriglyceridemia than girls without CPP.

PEGylated AdipoRon derivatives improve glucose and lipid metabolism under insulinopenic and high-fat diet conditions

The pleiotropic actions of adiponectin in improving cell survival and metabolism have motivated the development of small-molecule therapeutic agents for treating diabetes and lipotoxicity. AdipoRon is a synthetic agonist of the adiponectin receptors, yet is limited by its poor solubility and bioavailability. In this work, we expand on the protective effects of AdipoRon in pancreatic β-cells and examine how structural modifications could affect the activity, pharmacokinetics, and bioavailability of this small molecule. We describe a series of AdipoRon analogs containing amphiphilic ethylene glycol (PEG) chains. Among these, AdipoRonPEG5 induced pleiotropic effects in mice under insulinopenic and high-fat diet (HFD) conditions. While both AdipoRon and AdipoRonPEG5 substantially attenuate palmitate-induced lipotoxicity in INS-1 cells, only AdipoRonPEG5 treatment is accompanied by a significant reduction in cytotoxic ceramides. In vivo, AdipoRonPEG5 can substantially reduce pancreatic, hepatic, and serum ceramide species, with a concomitant increase in the corresponding sphingoid bases and improves insulin sensitivity of mice under HFD feeding conditions. Furthermore, hyperglycemia in streptozotocin (STZ)-induced insulinopenic adiponectin-null mice is also attenuated upon AdipoRonPEG5 treatment. Our results suggest that AdipoRonPEG5 is more effective in reducing ceramides and dihydroceramides in the liver of HFD-fed mice than AdipoRon, consistent with its potent activity in activating ceramidase in vitro in INS-1 cells. Additionally, these results indicate that the beneficial effects of AdipoRonPEG5 can be partially attributed to improved pharmacokinetics as compared with AdipoRon, thus suggesting that further derivatization may improve affinity and tissue-specific targeting.

Influence of AMY1A copy number variations on obesity and other cardiometabolic risk factors: A review of the evidence

The rising incidence of obesity and type 2 diabetes is contributing to the escalating burden of disease globally. These metabolic disorders are closely linked with diet and in particular with carbohydrate consumption; hence, it is important to understand the underlying mechanisms that influence carbohydrate metabolism. Amylase, the enzyme responsible for the digestion of starch, is coded by the genes AMY1A, AMY1B, and AMY1C (salivary amylase) and AMY2A and AMY2B (pancreatic amylase). Previous studies demonstrate wide variations in AMY1A copy numbers, which can be attributed to several genetic, nutritional, and geographical diversities seen in populations globally. Current literature suggests that AMY1A copy number variations are important in obesity and other cardiometabolic disorders through their effects on glucose and lipid homeostasis, inflammatory markers, and the gut microbiome. This review synthesizes the available evidence to improve understanding of the role of AMY1A in obesity and related cardiometabolic risk factors and disorders including insulin resistance and type 2 diabetes, cardiovascular risk and inflammation, and the gut microbiome.

Effects of Ramadan intermittent fasting on leptin and adiponectin: a systematic review and meta-analysis

OBJECTIVES

Ramadan intermittent fasting may affect whole-body metabolism by affecting appetite-related hormones. This systematic review and meta-analysis aimed to clarify the possible effects of Ramadan intermittent fasting on the main hormones regulating appetite and satiety, including leptin and adiponectin.

METHODS

All English language papers in the PubMed, Scopus, and Embase databases were searched using the keywords "Ramadan fasting", "adiponectin", and "leptin", up to 2020. Data extraction was conducted based on the main data of the studies; the primary outcomes of the analysis were mean changes of adiponectin and leptin levels during the holy month of Ramadan in fasted subjects.

MAIN RESULTS

Data of 16 eligible studies, conducted between 2003 and 2020, were included in the systematic review. Of these, 10 studies with complete data on leptin and adiponectin were included in the meta-analysis. A significant decrease in leptin levels was observed after Ramadan fasting (WMD = -2.28 ng/ml, 95% CI = -3.72, -0.84). Ramadan fasting had no significant effect on adiponectin levels (WMD = 2.19 ng/ml, 95% CI = -0.29, 4.67). Sub-group analysis demonstrated a greater decrease in leptin levels among normal-weight subjects compared to those of overweight/obese subjects (WMD = -4.67 ng/ml, 95% CI = -6.03, -3.31 vs. WMD = -3.43 ng/ml, 95% CI = -5.69, -1.17).

CONCLUSION

Ramadan fasting may decrease leptin levels, especially in normal-weight subjects. There was high heterogeneity, which may be explained by the differences between the wide ranges of study conditions.

FTO gene-lifestyle interactions on serum adiponectin concentrations and central obesity in a Turkish population

The aim of the study was to investigate whether lifestyle factors modify the association between fat mass and obesity-associated (FTO) gene single nucleotide polymorphisms (SNPs) and obesity in a Turkish population. The study included 400 unrelated individuals, aged 24-50 years recruited in a hospital setting. Dietary intake and physical activity were assessed using 24-hour dietary recall and self-report questionnaire, respectively. A genetic risk score (GRS) was developed using FTO SNPs, rs9939609 and rs10163409. Body mass index and fat mass index were significantly associated with FTO SNP rs9939609 (p = 0.001 and p = 0.002, respectively) and GRS (p = 0.002 and p = 0.003, respectively). The interactions between SNP rs9939609 and physical activity on adiponectin concentrations, and SNP rs10163409 and dietary protein intake on increased waist circumference were statistically significant (Pinteraction = 0.027 and Pinteraction = 0.044, respectively). Our study has demonstrated that the association between FTO SNPs and central obesity might be modified by lifestyle factors in this Turkish population.

A Novel Role of Bergamottin in Attenuating Cancer Associated Cachexia by Diverse Molecular Mechanisms

Simple Summary

Cachexia has been generally associated with cancer causing skeletal muscle atrophy, adipose tissue atrophy, weight loss, anorexia, asthenia, and anemia, which can significantly reduce the quality of life. Our aim was to evaluate the potential effects of bergamottin on cancer-cachexia-induced muscle and fat loss. We observed a decrease in the levels of the muscle atrophy factors MuRF-1 and Atrogin-1 and increases in C/EBPα and PPARγ expression levels by bergamottin under in vitro settings. The in vivo effect of bergamottin on the inhibition of weight loss in mice and its potential inhibitory effects on cancer-induced cachexia were confirmed through analysis using tissue samples from a pancreatic cancer mouse model.

Abstract

Purpose: The potential effects of bergamotiin (BGM) on the suppression of cancer cachexia was evaluated under in vitro and in vivo conditions to investigate its possible inhibitory effects on the muscle and fat loss. Method: The differentiated C2C12 and 3T3L1 cells were treated with BGM after the induction of cancer-cachexia with pancreatic cancer conditioned media (CM). The expression levels of the various molecules involved in the differentiation and loss of muscle and fat (MuRF-1, Atrogin-1, C/EBPα, and PPARγ) were analyzed by Western blot and oil red O staining. For in vivo experiment, MIA PaCa-2 cells were injected into the mice (n = 6), and then BGM (1 mg/kg) was intraperitoneally administered to analyze muscle and adipose tissue by Hematoxylin and Eosin staining and Western blot. Result: BGM displayed a significant effect on the inhibition of muscle and fat catabolism under both in vitro and in vivo conditions. The results of the in vivo experiment revealed a remarkable suppressive effect of BGM on the weight loss in mice. Conclusions: The potential effects of BGM on the inhibition of muscle and fat catabolism in vitro and in vivo were thus confirmed. Based on the results, the impact of BGM on cancer cachexia could be possibly analyzed in the future clinical studies.

The Relationship Between Thyroid Function and Body Composition, Leptin, Adiponectin, and Insulin Sensitivity in Morbidly Obese Euthyroid Subjects Compared to Non-obese Subjects

Background/Objectives

Thyroid function tests (TFTs) changes in obese people have been studied with increasing interest, however, studies have been inconsistent hence it remains poorly understood. We compared the TFTs of morbidly obese euthyroid Saudi subjects with non-obese controls and then we examined the influence of leptin, adiponectin, and insulin resistance on TFTs.

Subjects/Methods

Fifty-five euthyroid obese subjects attending bariatric surgery clinic and 52 non-obese age-and gender-matched controls were recruited. We measured body weight, BMI, body composition, thyroid-stimulating hormone (TSH), Free T4 (FT4), Free T3(FT3), thyroid antibodies, fasting leptin, adiponectin, and lipid profile. Insulin resistance was quantified by HOMA-IR. Data are presented as mean ± SEM.

Results

Mean BMI was 45.6 ± 1.5 and 23.2 ± 0.5 kg/m², for the obese and non-obese controls, respectively, P value < 0.001. Mean TSH was 2.7 ± 0.18 mIU/L in obese subjects and 1.7 ± 0.13 mIU/L (0.27-4.2) in the non-obese controls, respectively, P value .014. Mean FT3 was 3.9 ± 0.1 pmol/L (3.1-6.8) in obese subjects compared to 5.0 ± 0.1 pmol/L in non-obese controls, respectively, P value 0.001, however, FT4 was similar in the 2 groups. In the whole group (N = 107), BMI correlated positively with TSH and negatively with FT3. Leptin correlated negatively with both FT4 and FT3 in the non-obese group only while none of the TFTs correlated with HOMA-IR or adiponectin in either group. Binary logistic regression showed that each 1 unit increase in TSH increased the odds of becoming obese by 12.7, P value 0.009, 95 C.I. (1.9-85.0). Conversely, each - unit increase in FT3 decreased the odds of becoming obese by 0.2, P value 0.023, 95% C.I. (0.05-0.80).

Conclusions

We report a small increase in TSH and a small decrease in FT3 within the normal range in obese subjects compared to non-obese controls. We also report a positive correlation between TSH and BMI with increased odds ratio of becoming obese with the increase in TSH and decrease in FT3. These changes may be either causally related or adaptive to the obesity state. FT4 and FT3 seem to correlate with leptin (but not with adiponectin or HOMA-IR) in the non-obese controls only. Larger mechanistic studies are needed to further elucidate the interesting association between obesity and TFTs.

Adiponectin enhances the bioenergetics of cardiac myocytes via an AMPK- and succinate dehydrogenase-dependent mechanism

Adiponectin is one of the most abundant circulating hormones, which through adenosine monophosphate-activated protein kinase (AMPK), enhances fatty acid and glucose oxidation, and exerts a cardioprotective effect. However, its effects on cellular bioenergetics have not been explored. We have previously reported that 5-aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR, an AMPK activator) enhances mitochondrial respiration through a succinate dehydrogenase (SDH or complex II)-dependent mechanism in cardiac myocytes, leading us to predict that Adiponectin would exert a similar effect via activating AMPK. Our results show that Adiponectin enhances basal mitochondrial oxygen consumption rate (OCR), ATP production, and spare respiratory capacity (SRC), which were all abolished by the knockdown of AMPKγ1, inhibition of SDH complex assembly, via the knockdown of the SDH assembly factor 1 (Sdhaf1), or inhibition of SDH activity. Additionally, Adiponectin alleviated hypoxia-induced reductions in OCR and ATP production, in a Sdhaf1-dependent manner, whereas overexpression of Sdhaf1 confirmed its sufficiency for mediating these effects. Importantly, the levels of holoenzyme SDH under the various conditions correlated with OCR. We also show that the effects of Adiponectin, AMPK, Sdhaf1, as well as, SDH complex assembly all required sirtuin 3 (Sirt3). In conclusion, Adiponectin potentiates mitochondrial bioenergetics via promoting SDH complex assembly in an AMPK-, Sdhaf1-, and Sirt3-dependent fashion in cardiac myocytes.

Effects of Ultramarathon Running on Mitochondrial Function of Platelets and Oxidative Stress Parameters: A Pilot Study

Only a few studies have evaluated changes in mitochondrial function and oxidative stress associated with ultramarathon running. Invasive biopsies are needed to assess mitochondrial function of skeletal muscle, which may not be well tolerated by some individuals. Platelets (PLTs) as a metabolically highly active and homogenous cell population were suggested as a potentially valuable surrogate to investigate mitochondrial function. Thus, this study was aimed to evaluate mitochondrial function of PLTs and its association with individual race performance and markers of oxidative stress, muscle damage and renal dysfunction. Race performance and mitochondrial function (high-resolution respirometry, HRR) of PLTs using different substrates inducing ROUTINE, LEAK, N-pathway control state (Complex I linked oxidative phosphorylation; CI, OXPHOS), NS-pathway control state (CI + II linked OXPHOS and electron transfer pathway; ET), S-pathway control state (CII linked ET) as well as parameters of oxidative stress and antioxidant capacity, and markers of muscle and renal injury were assessed in eight male ultramarathon runners (26–45 years) before, immediately after and 24 h after an ultramarathon race (PRE, POST, and REC). Ultramarathon running induced an increase in LEAK O₂ flux of PLT mitochondria and slight, largely non-significant changes in the oxidant/antioxidant balance. Levels of creatine kinase (CK), lactate dehydrogenase (LDH), blood urea nitrogen, and creatinine were all significantly elevated POST and remained high in REC. There were inverse correlations between race time and N-linked substrate state PRE-POST, and changes in CK and LDH levels were significantly related to PLT mitochondrial LEAK and N-linked respiration PRE. Although race-related changes in respirometry parameters of PLT mitochondria were rather small, a somewhat more pronounced increase in the relative N-linked respiration in faster runners might suggest PLT CI as indicator of physical fitness. The higher PLT LEAK PRE and diminished increase of CK during the race may represent a prophylactic preconditioning and the slight but non-significant elevation of the antioxidant potential post-race as a protective consequence of the race-related oxidative stress and potential threat to the kidney. Our findings point toward an interrelationship between mitochondrial function of PLTs, individual fitness levels and extreme physical and metal stresses, which stimulates further research.

Adiponectin Promotes Maternal β-Cell Expansion Through Placental Lactogen Expression

Hypoadiponectinemia is a risk factor of gestational diabetes mellitus (GDM). Our previous study reported that adiponectin gene knockout mice (Adipoq ^-/- ) develop GDM due to insulin insufficiency. The main objective of this study was to elucidate the underlying mechanism through which adiponectin controls islet expansion during pregnancy. A significant reduction in β-cell proliferation rates, β-cell areas, and blood insulin concentrations was detected in Adipoq ^-/- mice at midpregnancy. Surprisingly, conditionally knocking down adiponectin receptor 1 (AdipoR1) or AdipoR2 genes in β-cells during pregnancy did not reduce β-cell proliferation rates or blood insulin concentrations. In vitro adiponectin treatment also failed to show any effect on β-cell proliferation of isolated pancreatic islets. It was reported that placental lactogen (PL) plays a crucial role in pregnancy-induced maternal β-cell proliferation. A significant decrease in phosphorylation of signal transducer and activator of transcription 5, a downstream molecule of PL signaling, was observed in islets from Adipoq ^-/- dams. The mRNA levels of mouse PL genes were robustly decreased in the placentas of Adipoq ^-/- dams. In contrast, adiponectin treatment increased PL expression in human placenta explants and JEG3 trophoblast cells. Most importantly, bovine PL injection restored β-cell proliferation and blood insulin concentrations in Adipoq ^-/- dams. Together, these results demonstrate that adiponectin plays a vital role in pregnancy-induced β-cell proliferation by promoting PL expression in trophoblast cells.

Characterization and Transcriptome Analysis of Exosomal and Nonexosomal RNAs in Bovine Adipocytes

Exosomes are endosome-derived extracellular vesicles that allow intercellular communication. However, the biological significance of adipocyte exosomal RNAs remains unclear. To determine the role of RNAs from bovine adipocytes and exosomes in bovine adipogenesis, exosomal and nonexosomal RNAs were extracted from three bovine primary white adipocyte samples and then profiles were generated using DNBSEQ/BGISEQ-500 technology. The RNAome of adipocytes consisted of 12,082 mRNAs, 8589 lncRNAs, and 378 miRNAs for a higher complexity that that detected in exosomes, with 1083 mRNAs, 105 lncRNAs, and 48 miRNAs. Exosomal miRNA-mRNA and lncRNA–miRNA–mRNA networks were constructed and enrichment analysis was performed to predict functional roles and regulatory mechanisms. Our study provides the first characterization of RNAs from bovine adipocyte and exosomes. The findings reveal that some RNAs are specifically packaged in adipocyte-derived exosomes, potentially enabling crosstalk between adipocytes and/or other cells that is mediated by exosomes. Our results greatly expand our understanding of exosomal RNAs from bovine adipocytes, and provide a reference for future functional investigations of adipocyte exosomal RNAs under normal physiological conditions.

Adiponectin Inhibits NLRP3 Inflammasome Activation in Nonalcoholic Steatohepatitis via AMPK-JNK/ErK1/2-NFκB/ROS Signaling Pathways

Adiponectin, an adipose-derived adipokine, possesses a hepatoprotective role in various liver disorders. It has been reported that hypoadiponectinemia can affect with the progression of non-alcoholic fatty liver diseases (NAFLD). Inflammasome activation has been recognized to play a major role during the progression of NAFLD. This research aimed to explore the effect of adiponectin on palmitate (PA)-mediated NLRP3 inflammasome activation and its potential molecular mechanisms. Male adiponectin-knockout (adiponectin-KO) mice and C57BL/6 (wild-type) mice were fed a high-fat-diet (HFD) for 12 weeks as an in vivo model of non-alcoholic steatohepatitis (NASH). Serum biochemical markers, liver histology and inflammasome-related gene and protein expression were determined. In addition, the hepatocytes isolated from wide type mice were exposed to PA in the absence or presence of adiponectin and/or AMPK inhibitor. The activation of NLRP3 inflammasome was assessed by mRNA and protein expression. Furthermore, ROS production and related signaling pathways were also evaluated. In the in vivo experiments, excessive hepatic steatosis with increased NLRP3 inflammasome and its complex expression were found in adiponectin-KO mice compared to wild-type mice. Moreover, the expression levels of NLRP3 inflammasome pathway molecules (NFκB and ROS) were upregulated, while the phosphorylation levels of AMPK, JNK, and Erk1/2 were downregulated in adiponectin-KO mice compared with wild-type mice. In the in vitro study, PA increased lipid droplet deposition, NF-kB signaling and ROS production. Additionally, PA significantly promoted NLRP3 inflammasome activation and complex gene and protein expression in hepatocytes. Adiponectin could abolish PA-mediated inflammasome activation and decrease ROS production, which was reversed by AMPK inhibitor (compound C). Furthermore, the results showed that the inhibitory effect of adiponectin on PA-mediated inflammasome activation was regulated by AMPK-JNK/ErK1/2-NFκB/ROS signaling pathway. Adiponectin inhibited PA-mediated NLRP3 inflammasome activation in hepatocytes. Adiponectin analogs or AMPK agonists could serve as a potential novel agent for preventing or delaying the progression of NASH and NAFLD.

Neurochemical regulators of food behavior for pharmacological treatment of obesity: current status and future prospects

In recent decades, obesity has become a pandemic disease and appears to be an ultimate medical and social problem. Existing antiobesity drugs show low efficiency and a wide variety of side effects. In this review, we discuss possible mechanisms underlying brain-gut-adipose tissue axis, as well as molecular biochemical characteristics of various neurochemical regulators of body weight and appetite. Multiple brain regions are responsible for eating behavior, hedonic eating and food addiction. The existing pharmacological targets for treatment of obesity were reviewed as well.

Association between breast milk adipokines with growth in breast feeding infants, a systematic review and meta-analysis

Objectives

Breast milk adipokines are associated with growth, body mass index (BMI) and weight gain in infants. In this study, the effect of breastmilk adipokines (leptin and adiponectin) on the BMI and weight gain of breast-fed infants was evaluated using systematic review and meta-analysis.

Materials and methods

We used PRISMA checklist for carrying out this study. 752 articles were collected from the database searching and other sources from 1994 to April 2019. According to the criteria in the study, 25 articles remained for evaluation. Eight papers were related to the effect of breast milk leptin on weight gain and BMI of infants that were evaluated by meta-analyzing. The adiponectin articles were surveyed by systematic review.

Results

There was no significant publication bias in the meta-analysis study. The results of random-effect model indicated a reverse and significant correlation between breastmilk leptin with weight gain and BMI (r=−0.331). The adiponectin level in breast milk was associated with the BMI and weight gain of infants.

Conclusions

Meta-analysis indicated a significant inverse correlation between breastmilk leptin with weight gain and BMI in infants; furthermore, the systematic review study expressed significant correlation between breast milk adiponectin with growth (BMI and weight gain) in infants.

Role of body visceral fat in hypertension and dyslipidemia among the diabetic and nondiabetic ethnic population of Tripura-A comparative study

Background:

Excess fat in the upper part of human body correlates with increased mortality and risk for diabetes, dyslipidemia, and hypertension. In India, there are very limited data available on the association of excess body visceral fat with hypertension and dyslipidemia independent of obesity and diabetes.

Objective:

The objective of this study is to assess the role of body visceral fat percentage in hypertension and dyslipidemia among diabetic and nondiabetic indigenous ethnic population of Tripura.

Methods:

Random blood sugar test was done for each of the study subjects with the help of a standard and validated glucometer. Then, blood samples were obtained after an 8–12-h overnight fast using vacutainer. Later on, all the blood samples were transported to the MRU laboratory at Agartala Government Medical College maintaining cold chain for following investigations: (1) FBS, PP by GOD-POD method; (2) HbA1c by immunoturbidimetric method; (3) cholesterol estimation by CHOD-PAP method; and (4) triglyceride estimation by glycerol phosphate oxidase method.

Results:

In this study, it has been found that 62.5% diabetic subjects having high body visceral fat are suffering from Dyslipidemia, whereas only 42.9% nondiabetic subjects with high body visceral fat percentage are having dyslipidemia. Fisher's exact test showed association between diabetes status and body visceral fat (P = 0.048). It has been also observed that there was significant (P < 0.05) association between hypertension and body visceral fat among local indigenous ethnic population of Tripura.

Conclusion:

Body visceral fat percentage is significantly associated with hypertension, dyslipidemia, and type-2 diabetes among indigenous ethnic population of Tripura.

Resemblance and differences in dietary restriction nephroprotective mechanisms in young and old rats

Dietary restriction (DR) is the strategy ameliorating the morbidity of various pathologies, including age-associated diseases. Acute kidney injury (AKI) remains a problem for the elderly with DR being a promising approach for diminishing its consequences. We evaluated the possible nephroprotective potential of short-term DR in young and old rats. DR in young rats resulted in pronounced beneficial effects normalizing lipid metabolism (triglycerides concentration, adiponectin level) activating autophagic-lysosomal system evaluated by LC3II/LC3I ratio, LAMP1, p62/SQSTM1 levels, and LysoTracker Green staining. DR had a remarkable recovering effect on mitochondrial structure and functions including regaining of mitochondrial membrane potential, the elevation of SIRT-3, PGC-1α, _Bcl-XL levels and partial restoration of ultrastructure. The beneficial effects of DR resulted in the mitigation of oxidative stress including a decrease in levels of protein carbonylation and lipid peroxidation. Aging led to decreased activity of autophagy, elevated oxidative stress and impaired kidney regenerative capacity. Eventually, in old rats, even 8-week DR was not able to ameliorate AKI, but it caused some rejuvenating effects including elevation of mitochondrial membrane potential and Bcl-X_L levels, as well as lowered severity of the oxidative stress. Thus, the age-associated decline of protective signaling demands extended DR to achieve nephroprotective potential in old animals.

Association between changes in bioactive osteocalcin and glucose homeostasis after biliopancreatic diversion

PURPOSE

Bone may regulate glucose homeostasis via uncarboxylated bioactive osteocalcin (ucOCN). This study explored whether changes in ucOCN and bone remodeling are associated with change in glucose homeostasis after biliopancreatic diversion (BPD).

METHODS

In this secondary exploratory analysis of a 1-year prospective observational study, 16 participants (11 men/5 women; 69% with type 2 diabetes; mean BMI 49.4 kg/m²) were assessed before, 3 days, 3 months and 12 months after BPD. Changes in plasma ucOCN and bone markers (C-terminal telopeptide (CTX), total osteocalcin (OCN)) were correlated with changes in insulin resistance or sensitivity indices (HOMA-IR; adipose tissue insulin resistance index (ADIPO-IR) and insulin sensitivity index (SI) from the hyperinsulinemic-euglycemic clamp), insulin secretion rate (ISR) from the hyperglycemic clamp, and disposition index (DI: SI × ISR) using Spearman correlations before and after adjustment for weight loss.

RESULTS

ucOCN was unchanged at 3 days but increased dramatically at 3 months (+257%) and 12 months (+498%). Change in ucOCN correlated significantly with change in CTX at 3 months (r = 0.62, p = 0.015) and 12 months (r = 0.64, p = 0.025) before adjustment for weight loss. It also correlated significantly with change in fasting insulin (r = -0.53, p = 0.035), HOMA-IR (r = -0.54, p = 0.033) and SI (r = 0.52, p = 0.041) at 3 days, and ADIPO-IR (r = -0.69, p = 0.003) and HbA_1c (r = -0.69, p = 0.005) at 3 months. Change in OCN did not correlate with any glucose homeostasis indices. Results were similar after adjustment for weight loss.

CONCLUSION

The increase in ucOCN may be associated with the improvement in insulin resistance after BPD, independently of weight loss. These findings need to be confirmed in larger, less heterogeneous populations.

Adiponectin and leptin gene variants and their effects on body weight trajectories in children from birth to 6 years of age: the PREDI Study

Excess body weight confers a high risk to human health. Body weight variation between subjects can be partially explained by genetic differences. The aim of the present study was to investigate the association of genetic variants in the ADIPOQ (rs2241766) and LEP (rs7799039) genes with body weight trajectories in children from birth to 6 years of age. This was a prospective cohort (PREDI Study). Socio-economic, biological and anthropometric data were collected at four time points: at birth in the maternity unit; 1-2, 4-5 and 6 years old at the participants' homes. Genotyping was performed by PCR-restriction fragment length polymorphism. Poisson regression and linear mixed-effect regression models were used to address the association of ADIPOQ and LEP genotypes with BMI. Excessive body weight at pre-pregnancy (β = 0·339, P = 0·01) and excessive gestational weight gain (β = 0·51, P < 0·001) were associated with children's BMI trajectory from birth to 6 years. The ADIPOQ-rs2241766 TG or GG genotype was associated with a higher risk of excess body weight in the first 6 years of life (both sexes relative risk 1·25, 95 % CI 1·01, 1·56; female relative risk 1·67, 95 % CI 1·20, 2·31). BMI increased over the years according to the presence of the TG or GG genotype (β = 0·01, 95 % CI 0·01, 0·02), particularly in females (β = 0·02, 95 % CI 0·01, 0·04). The ADIPOQ-rs2241766 TG and GG genotypes increased the risk of excess body weight in children from birth to 6 years of age and had a positive effect on body weight trajectories in girls. The LEP-rs7799039 genetic variant was not associated with body weight trajectory in children.

Acute intracerebroventricular injection of chemerin-9 increases systemic blood pressure through activating sympathetic nerves via CMKLR1 in brain

Chemerin is an adipocytokine involved in inflammation and lipid metabolism via G protein-coupled receptor, chemokine-like receptor (CMKLR)1. Since the important nuclei regulating pressure (BP) exist in the brain, we examined the effects of acute intracerebroventricular (i.c.v.) injection of chemerin-9 on systemic BP and explored underlying mechanisms. We examined the effects of acute i.c.v. injection of chemerin-9 (10 nmol/head) on systemic BP by a carotid cannulation method in the control or CMKLR1 small interfering (si) RNA-treated Wistar rats (0.04 nmol, 3 days, i.c.v.). We examined protein expression of CMKLR1 around brain ventricles by Western blotting. We examined the effects of acute i.c.v. injection of chemerin-9 on serum adrenaline by a high performance liquid chromatography. In the control siRNA-treated rats, chemerin-9 significantly increased mean BP, which reached a peak at 2 to 4 min after injection. On the other hand, in the CMKLR1 siRNA-treated rats, chemerin-9 did not affect the mean BP. Protein expression of CMKLR1 specifically in subfornical organ (SFO) and paraventricular nucleus (PVN) from the CMKLR1 siRNA-treated rats decreased compared with the control siRNA-treated rats. In the control siRNA-treated rats, chemerin-9 increased serum adrenaline level. On the other hand, in the CMKLR1 siRNA-treated rats, chemerin-9 did not affect the serum adrenaline level. Further, pretreatment with prazosin, an α-adrenaline receptor blocker, significantly prevented the pressor responses induced by chemerin-9. In summary, we for the first time demonstrated that chemerin-9 stimulates the sympathetic nerves via CMKLR1 perhaps expressed in SFO and PVN, which leads to an increase in systemic BP.

Mitochondrial Dynamics and Microglia as New Targets in Metabolism Regulation

Energy homeostasis regulation is essential for the maintenance of life. Neuronal hypothalamic populations are involved in the regulation of energy balance. In order play this role, they require energy: mitochondria, indeed, have a key role in ensuring a constant energy supply to neurons. Mitochondria are cellular organelles that are involved in dynamic processes; their dysfunction has been associated with many diseases, such as obesity and type 2 diabetes, indicating their importance in cellular metabolism and bioenergetics. Food intake excess can induce mitochondrial dysfunction with consequent production of reactive oxygen species (ROS) and oxidative stress. Several studies have shown the involvement of mitochondrial dynamics in the modulation of releasing agouti-related protein (AgRP) and proopiomelanocortin (POMC) neuronal activity, although the mechanisms are still unclear. However, recent studies have shown that changes in mitochondrial metabolism, such as in inflammation, can contribute also to the activation of the microglial system in several diseases, especially degenerative diseases. This review is aimed to summarize the link between mitochondrial dynamics and hypothalamic neurons in the regulation of glucose and energy homeostasis. Furthermore, we focus on the importance of microglia activation in the pathogenesis of many diseases, such as obesity, and on the relationship with mitochondrial dynamics, although this process is still largely unknown.

Effects of Biliopancreatic Diversion on Bone Turnover Markers and Association with Hormonal Factors in Patients with Severe Obesity

BACKGROUND

This study evaluated early and medium-term changes in bone turnover markers, and their associations with weight loss, total bone mineral density (BMD), and hormonal changes after biliopancreatic diversion (BPD).

METHODS

Ancillary study from a one-year prospective cohort of 16 individuals assessed before, 3 days, 3 and 12 months after BPD. Bone turnover markers (C-terminal telopeptide (CTX), intact osteocalcin (OC), sclerostin, and osteoprotegerin (OPG)) and several hormones were measured at each visit. Total BMD by DXA was assessed at baseline, 3 and 12 months after BPD. Three participants were lost to follow-up.

RESULTS

CTX increased significantly at 3 days (+ 66%), 3 months (+ 219%), and 12 months (+ 295%). OC decreased at 3 days (- 19%) then increased at 3 months (+ 69%) and 12 months (+ 164%). Change in sclerostin was only significant between 3 days and 3 months (+ 13%), while change in OPG was significant between baseline and 3 days (+ 48%) and baseline and 12 months (+ 45%). CTX increase correlated negatively with weight loss at 3 (r = - 0.63, p = 0.009) and 12 months (r = - 0.58, p = 0.039), and total BMD decrease (r = - 0.67, p = 0.033) at 12 months. Change in insulin and adiponectin correlated with changes in bone turnover markers independently of weight loss.

CONCLUSION

BPD causes an earlier and greater increase in bone resorption over bone formation markers and a decrease in total BMD. Sclerostin did not increase as expected following extensive weight loss. Changes in insulin and adiponectin seem to play a role in the activation of bone remodeling after BPD.