Three new players in energy regulation: preptin, adropin and irisin

Effects of irisin and exercise on adropin and betatrophin in a new metabolic syndrome model

Metabolic syndrome (MetS) is a prevalent public health problem. Uric acid (UA) is increased by MetS. We investigated whether administration of UA and 10% fructose (F) would accelerate MetS formation and we also determined the effects of irisin and exercise. We used seven groups of rats. Group 1 (control); group 2 (sham); group 3 (10% F); group 4 (1% UA); group 5 (2% UA); group 6 (10% F + 1% UA); and Group 7, (10% F + 2% UA). After induction of MetS (groups 3 -7), Group 3 was divided into three subgroups: 3A, no further treatment; 3B, irisin treatment; 3C, irisin treatment + exercise. Group 4, 1% UA, which was divided into three subgroups: 4A, no further treatment; 4B, irisin treatment; 4C, Irisin treatment + exercise. Group 5, 2% UA, which was divided into three subgroups: 5A, no further treatment; 5B, irisin treatment; 5C, irisin treatment + exercise. Group 6, 10% F + 1% UA, which was divided into three subgroups: 6A, no further treatment; 6B, irisin treatment; 6C, irisin treatment + exercise. Group 7, 10% F + 2% UA, which was divided into three subgroups: 7A, no further treatment; 7B, irisin treatment; 7C, irisin treatment + exercise., İrisin was administered 10 ng/kg irisin intraperitoneally on Monday, Wednesday, Friday, Sunday each week for 1 month. The exercise animals (in addition to irisin treatment) also were run on a treadmill for 45 min on Monday, Wednesday, Friday, Sunday each week for 1 month. The rats were sacrificed and samples of liver, heart, kidney, pancreas, skeletal muscles and blood were obtained. The amounts of adropin (ADR) and betatrophin in the tissue supernatant and blood were measured using an ELISA method. Immunohistochemistry was used to detect ADR and betatrophin expression in situ in tissue samples. The duration of these experiments varied from 3 and 10 weeks. The order of development of MetS was: group 7, 3 weeks; group 6, 4 weeks; group 5, 6 weeks; group 4, 7 weeks; group 3, 10 weeks. Kidney, liver, heart, pancreas and skeletal muscle tissues are sources of adropin and betatrophin. In these tissues and in the circulation, adropin was decreased significantly, while betatrophin was increased significantly due to MetS; irisin + exercise reversed this situation. We found that the best method for creating a MetS model was F + UA2 supplementation. Our method is rapid and simple. Irisin + exercise was best for preventing MetS.

Adropin: A crucial regulator of cardiovascular health and metabolic balance

Adropin, a peptide discovered in 2008, has gained recognition as a key regulator of cardiovascular health and metabolic balance. Initially identified for its roles in energy balance, lipid metabolism, and glucose regulation, adropin has also been found to improve cardiovascular health by enhancing endothelial function, modulating lipid profiles, and reducing oxidative stress. These protective mechanisms suggest that adropin may be able to help prevent conditions such as atherosclerosis, hypertension, and other cardiovascular diseases. Research has established connections between adropin and cardiovascular risk factors, such as obesity, insulin resistance, and dyslipidemia, positioning it as a valuable biomarker for evaluating cardiovascular disease risk. New studies highlight adropin's diagnostic and prognostic significance, showing that higher levels are linked to better cardiovascular outcomes, while lower levels are associated with a higher risk of cardiovascular diseases. This review aims to summarize current knowledge on adropin, emphasizing its significance as a promising focus in the intersection of cardiovascular health and metabolic health. By summarizing the latest research findings, this review aims to offer insights into the potential applications of adropin in both clinical practice and research, leading to a deeper understanding of its role in maintaining cardiovascular and metabolic health.

Hepatokines: unveiling the molecular and cellular mechanisms connecting hepatic tissue to insulin resistance and inflammation

Insulin resistance arising from Non-Alcoholic Fatty Liver Disease (NAFLD) stands as a prevalent global ailment, a manifestation within societies stemming from individuals' suboptimal dietary habits and lifestyles. This form of insulin resistance emerges as a pivotal factor in the development of type 2 diabetes mellitus (T2DM). Emerging evidence underscores the significant role of hepatokines, as hepatic-secreted hormone-like entities, in the genesis of insulin resistance and eventual onset of type 2 diabetes. Hepatokines exert influence over extrahepatic metabolism regulation. Their principal functions encompass impacting adipocytes, pancreatic cells, muscles, and the brain, thereby playing a crucial role in shaping body metabolism through signaling to target tissues. This review explores the most important hepatokines, each with distinct influences. Our review shows that Fetuin-A promotes lipid-induced insulin resistance by acting as an endogenous ligand for Toll-like receptor 4 (TLR-4). FGF21 reduces inflammation in diabetes by blocking the nuclear translocation of nuclear factor-κB (NF-κB) in adipocytes and adipose tissue, while also improving glucose metabolism. ANGPTL6 enhances AMPK and insulin signaling in muscle, and suppresses gluconeogenesis. Follistatin can influence insulin resistance and inflammation by interacting with members of the TGF-β family. Adropin show a positive correlation with phosphoenolpyruvate carboxykinase 1 (PCK1), a key regulator of gluconeogenesis. This article delves into hepatokines' impact on NAFLD, inflammation, and T2DM, with a specific focus on insulin resistance. The aim is to comprehend the influence of these recently identified hormones on disease development and their underlying physiological and pathological mechanisms.

The role of serum adropin in determining the clinical outcomes of patients with traumatic brain injury: a case-control study

OBJECTIVE

It has been determined that adropin has a role in tissue healing. This study aimed to determine the effects of head trauma on the tissues and blood levels of patients admitted to the emergency department.

METHODS

The study group was divided into two to compare the adropin level in healthy individuals and patients with head trauma. Blood tests from patients and healthy volunteers were compared using the adropin kit. Adropin levels, Glasgow Coma Scale, and revised scores of trauma patients were recorded and analyzed.

RESULTS

All patients in the trauma group had significantly higher adropin levels than the control group. Among these patients, the adropin level of the discharged patients was higher than the others. In addition, patients with high Glasgow Coma Scale and normal blood pressure were found to have higher adropin levels than the others.

CONCLUSION

Although adropin cannot make a sharp distinction in determining the prognosis, the increase in its level in trauma patients shows that it triggers a protective mechanism.

Can irisin be developed as the molecular evolutionary clock based on the origin and functions?

Irisin, a myokine identified in 2012, has garnered research interest for its capacity to induce browning of adipocytes and improve metabolic parameters. As such, the potential therapeutic applications of this exercise-induced peptide continue to be explored. Though present across diverse animal species, sequence analysis has revealed subtle variation in the irisin protein. In this review, we consider the effects of irisin on disease states in light of its molecular evolution. We summarize current evidence for irisin's influence on pathologies and discuss how sequence changes may inform development of irisin-based therapies. Furthermore, we propose that the phylogenetic variations in irisin could potentially be leveraged as a molecular clock to elucidate evolutionary relationships.

Irisin/PGC-1α/FNDC5 pathway in Parkinson's disease: truth under the throes

Parkinson's disease (PD) is considered one of the most common neurodegenerative brain diseases which involves the deposition of α-synuclein. Irisin hormone, a newly discovered adipokine, has a valuable role in diverse neurodegenerative diseases. Therefore, this review aims to elucidate the possible role of the irisin hormone in PD neuropathology. Irisin hormone has a neuroprotective effect against the development and progression of various neurodegenerative disorders by increasing the expression of brain-derived neurotrophic factor (BDNF). Irisin hormone has anti-inflammatory, anti-apoptotic, and anti-oxidative impacts, thereby reducing the expression of the pro-inflammatory cytokines and the progression of neuroinflammation. Irisin-induced PGC-1α could potentially prevent α-synuclein-induced dopaminergic injury, neuroinflammation, and neurotoxicity in PD. Inhibition of NF-κB by irisin improves PGC-1α and FNDC5 signaling pathway with subsequent attenuation of PD neuropathology. Therefore, the irisin/PGC-1α/FNDC5 pathway could prevent dopaminergic neuronal injury. In conclusion, the irisin hormone has a neuroprotective effect through its anti-inflammatory and antioxidant impacts with the amelioration of brain BDNF levels. Further preclinical and clinical studies are recommended in this regard.

The Role of the Myokine Irisin in the Protection and Carcinogenesis of the Gastrointestinal Tract

Recently discovered irisin, a member of the myokines family, is a potential mediator of exercise-induced energy metabolism and a factor promoting browning of the white adipose tissue. Recent evidence indicates that this myokine, released from contracting muscles, can mediate the beneficial effects of exercise on health. Irisin may be a potential therapeutic agent against obesity and has been shown to play an important role in the protection of various cells, tissues, and organs due to its anti-inflammatory, antioxidative, and anti-cancer properties. Our aim was to review the recent experimental and clinical studies on irisin and its expression, release into the bloodstream, tissue targets, and potential contribution to the protective effects of exercise in the gastrointestinal tract. Particular emphasis was placed on inflammatory bowel disease, intestinal ischemia/reperfusion injury, periodontitis, and other digestive tract disorders, including carcinogenesis. Overall, irisin holds significant potential as a novel target molecule, offering a safe and therapeutic approach to treating various gastrointestinal diseases.

Effect of Boric Acid on Metabolic Peptides and Some Biochemical Parameters in Experimental Diabetic Rats

Boron (B) is an element that has recently been wondered and researched in many fields, especially due to its effects on energy metabolism. The aim of this study is to evaluate the effect of boric acid (BA) on newly discovered energy metabolism peptides that have not been studied before. In this study, the effects of 15 mg/kg of BA were evaluated in 24 Wistar rats. Groups were named as control group, 15 mg/kg BA group, streptozotocin (STZ)-induced experimental diabetic group, and STZ-induced experimental diabetic + 15 mg/kg BA administered group (STZ+15 mg/kg BA). Serum asprosin, nesfatin-1, preptin, insulin, total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), aspartate transaminase (AST), alanine transaminase (ALT), and glucose analyses were performed. In this study, the increase in glucose, TG, TC, LDL-C levels, and AST, ALT activities in STZ-induced groups were reduced with BA administration. While HDL-C level significantly decreased in the STZ group, the level approached the control group values after BA administration (p<0.001). As for peptides, although there was a statistically significant increase after 15 mg/kg BA administration, these levels did not approach the control group values (p<0.001). According to the findings, STZ-induced diabetes mellitus and the biochemical processes that develop accordingly change correlatively. This study showed that BA is effective in energy metabolism.

The Role of FNDC5/Irisin in Cardiovascular Disease

Disorders of cardiomyocyte metabolism play a crucial role in many cardiovascular diseases, such as myocardial infarction, heart failure and ischemia-reperfusion injury. In myocardial infarction, cardiomyocyte metabolism is regulated by mitochondrial changes and biogenesis, which allows energy homeostasis. There are many proteins in cells that regulate and control metabolic processes. One of them is irisin (Ir), which is released from the transmembrane protein FNDC5. Initial studies indicated that Ir is a myokine secreted mainly by skeletal muscles. Further studies showed that Ir was also present in various tissues. However, its highest levels were observed in cardiomyocytes. Ir is responsible for many processes, including the conversion of white adipose tissue (WAT) to brown adipose tissue (BAT) by increasing the expression of thermogenin (UCP1). In addition, Ir affects mitochondrial biogenesis. Therefore, the levels of FNDC5/Ir in the blood and myocardium may be important in cardiovascular disease. This review discusses the current knowledge about the role of FNDC5/Ir in cardiovascular disease.

Potential role of irisin in digestive system diseases

Digestive system diseases (DSD) are very complex conditions that severely threaten human health. Therefore, there is an urgent need to develop new pharmacological treatment strategies. Irisin, a myokine discovered in 2012, is produced by fibronectin type III domain-containing protein 5 (FNDC5), which is a transmembrane protein. Irisin is involved in promoting the browning of white adipose tissue, the regulation of energy metabolism, and the improvement of insulin resistance. Irisin is also an essential mediator of the inflammatory response, oxidative stress, and cell apoptosis. Recent studies have proved that irisin concentration is altered in DSD and exerts pivotal effects on the initiation, progression, and prognosis of these diseases through various mechanisms. Therefore, studying the expression and function of irisin may have great significance for the diagnosis and treatment of DSD. Here, we focus on irisin and explore the multiple molecular pathways targeted by irisin therapy. This review indicates that irisin can serve as a diagnostic marker or potential therapeutic agent for DSD. DATA AVAILABILITY: Not applicable.

Coating with tripolyphosphate-crosslinked chitosan as a novel approach for enhanced stability of emulsomes following oral administration: Rutin as a model drug with improved anti-hyperlipidemic effect in rats

The aim of the current study is to preserve the emulsomal vesicles against the harsh condition of gastrointestinal tract (GIT), after oral administration, employing tripolyphosphate (TPP)-crosslinked chitosan as a protective coating layer. Rutin was used as a model drug with evaluation of anti-hyperlipidemic activity in rats. The rutin loaded unmodified emulsomes were prepared using tripalmitin and soybean phosphatidylcholine (SPC), by thin film method. Drug loading for the prepared formulations ranged between 6.80 and 15.50 %. The selected formulation (RT-Emuls-6) comprised tripalmitin and SPC, molar ratio 1:1, and exhibited particle size (PS) and zeta potential (ZP) of 150.40 nm and -35.35 mV, respectively. RT-Emuls-6 was then modified by coating with either solely chitosan (RT-Emuls-6-Ch) or TPP-crosslinked chitosan (RT-Emuls-6-Ch-TPP-1). The latter exhibited PS and ZP values of 269.60 nm and 37.17 mV, respectively. Transmission electron microscopy of RT-Emuls-6-Ch-TPP-1 showed a dense pale greyish layer of a coating layer of chitosan crosslinked with TPP surrounding SPC bilayers. Fourier transform infrared spectroscopy analysis along with X-ray powder diffraction confirmed cross-linking between chitosan and TPP. Stability study in the simulated GIT fluids revealed that the order of rutin retained percentage was RT-Emuls-6-Ch-TPP-1 > RT-Emuls-6-Ch > RT-Emuls-6 (80.02, 50.66 and 44.41 %, respectively for simulated gastric fluid and 63.50, 55.66 and 24.00 %, respectively for simulated intestinal fluid, after 2 h incubation). Anti-hyperlipidemic activity of rutin loaded emulsomes was evaluated, after oral administration, in a high fat diet-induced hyperlipidemia in rats. The order of activity was as follows: RT-Emuls-6-Ch-TPP-1 > RT-Emuls-6-Ch > RT-Emuls-6 > free rutin. These findings revealed the potential of TPP-crosslinked chitosan as a protective coating layer for enhancing the stability of emulsomes against the harsh condition of GIT. RT-Emuls-6-Ch-TPP-1 had a potent anti-hyperlipidemic activity via regulation of lipids, oxidative stress, irisin and uncoupling protein 1.

Preptin: A New Bone Metabolic Parameter?

Preptin is a 34-aminoacid peptide derived from the E-peptide of pro-insulin-like growth factor 2 (pro-IGF2) that is co-secreted with insulin and upregulates glucose-mediated insulin secretion. High serum preptin levels were described in conditions associated with insulin resistance, such as polycystic ovary syndrome and type 2 diabetes mellitus (T2M). Insulin and also IGF2 are known to be anabolic bone hormones. The "sweet bone" in T2M usually associates increased density, but altered microarchitecture. Therefore, preptin was proposed to be one of the energy regulatory hormones that positively impacts bone health. Experimental data demonstrate a beneficial impact of preptin upon the osteoblasts. Preptin also appears to regulate osteocalcin secretion, which in turn regulates insulin sensitivity. Preptin is greatly influenced by the glucose tolerance status and the level of physical exercise, both influencing the bone mass. Clinical studies describe low serum preptin concentrations in osteoporosis in both men and women, therefore opening the way towards considering preptin a potential bone anabolic therapy. The current review addresses the relationship between preptin and bone mass and metabolism in the experimental and clinical setting, also considering the effects of preptin on carbohydrate metabolism and the pancreatic-bone loop.

A comparison of the associations between bone turnover markers and different sports fields: combat versus team sports

Sedentary life brings risks that include osteoporosis, while physical activity has many benefits for health in general and the skeletal system. Irisin is a hormone-like myokine regulated by mechanical force and it contributes to cortical and trabecular bone mineral density. This study aimed to investigate the effects of different types of sports on bone health by measuring elite athletes’ fibronectin type III domain 5 (FNDC5), N-terminal collagen type I extension propeptide (PINP), and C-terminal cross-linking telopeptide of type I collagen (CTXI) levels. Combat sports athletes, team sports athletes, and sedentary control subjects were enrolled. Serum levels of proteins were measured by ELISA. FNDC5 levels of elite athletes were higher compared to the sedentary controls (P=0.0014). The highest FNDC5 level was measured in wrestlers among all considered groups. The PINP levels of the athletes were also higher than those of the sedentary control group (P=0.1431). The highest PINP level was determined in boxers. The CTXI levels of the athletes were lower than those of the sedentary control (P<0.0001). The lowest CTXI level was seen in boxers. The FNDC5 and PINP levels of combat sports athletes were higher than those of team sports athletes (P=0.0134 and P=0.0262, respectively), while the CTXI levels of combat sports athletes were lower than those of team sports athletes (P<0.0001). Our results indicated that FNDC5, PINP, and CTXI levels are associated with physical activity. The effect of the exercises performed by athletes of specific sports on bone health has not been studied in much detail before. Combining different exercises for athletes of a particular sport may be more beneficial for bone health.

A new predictor for prediabetes: Chemerin

Objective: It was aimed to investigate irisin and chemerin levels in prediabetic individuals and their value in predicting prediabetes. Method: Thirty-eight prediabetic patients aged 18-65 years (22 impaired fasting glucose (IFG), 10 impaired glucose tolerance (IGT), 6 patients with coexisting IFG and IGT) and thirty-five healthy volunteers were included in which was designed as a cross-sectional study. The basic demographic characteristics of all participants in the case and control groups were compared with the serum chemerin, irisin, creatinine, aspartate aminotransferase (AST), alanine aminotransferase (ALT), high-density lipoprotein (HDL-cholesterol), low-density lipoprotein (LDL-cholesterol), triglyceride (TG), free thyroxine (sT4), and thyroid-stimulating hormone (TSH) levels. Result: Serum chemerin level was found to be higher in the prediabetic group (p=0.03), while no significant difference was found for the irisin level between the two groups. In the multivariate logistic regression analysis, we showed that chemerin was an independent risk factor in predicting prediabetes. There was a positive correlation (p=0.01, r=0.279) between all participants' body mass index (BMI) and chemerin level and a negative correlation between irisin level and high-density lipoprotein cholesterol (HDL-C) level, and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) (p=0.04 r=-0.295, p=0.01 r=-0.407, respectively). Conclusion: Chemerin is a new generation chemokine that predicts prediabetes. Studies aimed at irisin and chemerin may provide important role to prevent the prediabetes to Type 2 diabetes progression.

Galectin-1 in Obesity and Type 2 Diabetes

Galectin-1 is a carbohydrate-binding protein expressed in many tissues. In recent years, increasing evidence has emerged for the role of galectin-1 in obesity, insulin resistance and type 2 diabetes. Galectin-1 has been highly conserved through evolution and is involved in key cellular functions such as tissue maturation and homeostasis. It has been shown that galectin-1 increases in obesity, both in the circulation and in the adipose tissue of human and animal models. Several proteomic studies have independently identified an increased galectin-1 expression in the adipose tissue in obesity and in insulin resistance. Large population-based cohorts have demonstrated associations for circulating galectin-1 and markers of insulin resistance and incident type 2 diabetes. Furthermore, galectin-1 is associated with key metabolic pathways including glucose and lipid metabolism, as well as insulin signalling and inflammation. Intervention studies in animal models alter animal weight and metabolic profile. Several studies have also linked galectin-1 to the progression of complications in diabetes, including kidney disease and retinopathy. Here, we review the current knowledge on the clinical potential of galectin-1 in obesity and type 2 diabetes.

Effect of Adropin on Pancreas Exocrine Function in a Rat Model: A Preliminary Study

The aim was to investigate the potential effect of adropin (ADR) on pancreatic−biliary juice (PBJ) secretion (volume, protein content, trypsin activity) in a rat model. The animals were divided into control and five experimental groups: adropin, CCK-8 (CCK-8 stimulation), capsaicin (capsaicin deactivation of afferents), vagotomy (vagotomy procedure), and vagal stimulation (vagal nerve stimulation). The experiment consisted of four phases, during which vehicle (0.9% NaCl) and three ADR boluses (5, 10, and 20 µg/kg BW) were administered i.v. every 30 min. PBJ samples were collected from each rat at 15 min intervals after boluses. Exogenous ADR failed to affect the pancreatic responses after vagotomy and the capsaicin pretreatment and reduced the PBJ volume, protein outputs, and trypsin activity in the adropin, CCK-8, and vagal stimulation groups in a dose-dependent manner. In all these groups, volume of PBJ was reduced only by the highest dose of ADR (p < 0.001 for adropin group and p < 0.01 for CCK-8 and vagal stimulation groups), and the protein outputs were reduced by the administration of ADR 10 µg/kg BW (adropin and CCK-8 groups, p < 0.01 in both cases) and 20 µg/kg BW (p < 0.001 for adropin and CCK-8 groups, p < 0.01 for vagal stimulation group). The 10 µg/kg BW dose of ADR reduced the trypsin output in the CCK-8 group (p < 0.01), and the highest ADR dose reduced the trypsin output in the CCK-8 (p < 0.001) and vagal stimulation (p < 0.01) groups. In conclusion, adropin in the analyzed doses exhibits the negative feedback pathway. This mechanism seems to participate in the regulation of pancreatic juice secretion via an indirect vagal mechanism.

Adropin’s Role in Energy Homeostasis and Metabolic Disorders

Adropin is a novel 76-amino acid-peptide that is expressed in different tissues and cells including the liver, pancreas, heart and vascular tissues, kidney, milk, serum, plasma and many parts of the brain. Adropin, encoded by the Enho gene, plays a crucial role in energy homeostasis. The literature review indicates that adropin alleviates the degree of insulin resistance by reducing endogenous hepatic glucose production. Adropin improves glucose metabolism by enhancing glucose utilization in mice, including the sensitization of insulin signaling pathways such as Akt phosphorylation and the activation of the glucose transporter 4 receptor. Several studies have also demonstrated that adropin improves cardiac function, cardiac efficiency and coronary blood flow in mice. Adropin can also reduce the levels of serum triglycerides, total cholesterol and low-density lipoprotein cholesterol. In contrast, it increases the level of high-density lipoprotein cholesterol, often referred to as the beneficial cholesterol. Adropin inhibits inflammation by reducing the tissue level of pro-inflammatory cytokines such as tumor necrosis factor alpha and interleukin-6. The protective effect of adropin on the vascular endothelium is through an increase in the expression of endothelial nitric oxide synthase. This article provides an overview of the existing literature about the role of adropin in different pathological conditions.

The effectiveness of serum S100B, TRAIL, and adropin levels in predicting clinical outcome, final infarct core, and stroke subtypes of acute ischemic stroke patients

Introduction:

More than half of all worldwide deaths and disabilities were caused by stroke. Large artery atherosclerosis is identified as a high etiological risk factor because it accounts for 20% of ischemic stroke.

Objectives:

To identify the significance of TRAIL and adropin release and the relative changes related to S100B levels, as well as the relationship between these biomarkers and the final infarct core, the clinical outcome, and the presence of large artery atherosclerosis in acute stroke patients.

Materials and methods:

Over a one-year period, demographic, clinical, and neuroimaging findings of 90 consecutive patients with acute ischemic stroke were evaluated.

Results:

The mean age of participants was 69.28 ± 10 and 39 patients were female. The increased level of S100B and the decreased levels of sTRAIL with adropin were significantly associated with moderate to severe neurologic presentation (p=0.0001, p=0.002, p=0.002, respectively). On the control CT, a large infarct core was significantly associated with decreased serum levels of sTRAIL and adropin (p=0.001 and p=0.000, respectively); however, the levels of S100B were not significantly associated with good ASPECTS score (p=0.684). Disability and an unfavorable outcome were significantly related to the decreased level of sTRAIL and adropin (p=0.001 and p=0.000 for THRIVE score>5, respectively). Decreased sTRAIL and adropin levels and an increased S100B level were correlated with the presence of large artery atherosclerotic etiologic factors (p=0.000, p=0.000, p=0.036, respectively).

Conclusion:

TRAIL and adropin serum levels were associated with poor clinical outcomes and greater infarcted area in acute ischemic stroke patients.

The effect of nutrition and exercise training on irisin and semaphorin-3E levels in obese patients

We aimed to firstly examine the effects of nutrition and exercise training on irisin, Sema-3E, biochemical and inflammatory parameters in obese patients. This study was conducted using 37 individuals were divided into three groups according to body mass index (BMI) as non-obese, 1nd degree and 2nd degree obese individuals. Nutrition and exercise training were applied to groups for eight weeks. Insulin resistance decreased in non-obese and 1st degree obese subjects. HsCRP values decreased only in the second degree obese individuals. Adiponectin values were significantly decreased in all three groups. There was a negative correlation between serum adiponectin and plasma irisin levels both before and after treatment. Sema-3E levels increased significantly in only the first degree obese individuals, whereas plexin-D1 values did not change significantly in any group. Our findings indicate that nutrition and exercise training we apply improved both anthropometric measurements and biochemical parameters in obese and non-obese individuals.

Role of rs7903146 polymorphism and adropin serum level in patients with diabetes mellitus; a case-control study from Isfahan, Iran

BACKGROUND

Type-2 diabetes mellitus (T2DM) is the common endocrinopathy which characterised by insulin resistance, insufficient expression or secretion of insulin and decrement of insulin effectiveness. Although T2DM has unknown aetiology, the strongest susceptible gene in this disease is TCF7L2. Adropin peptide may have roles in T2DM pathogenesis due to several roles in glucose tolerance, decrement of insulin resistance, lipid metabolism and energy homoeostasis.

AIM

To evaluate the serum level of adropin in T2DM patients and comparing with healthy individuals as well as assessing frequency of rs7903146 genotypes/alleles in patients and control groups.

METHODS

We analysed the frequency of rs7903146 genotypes/alleles in 93 patients with T2DM disease and 53 healthy individuals by the method of polymerase chain reaction-restriction fragment length polymorphism analysis. The serum level of adropin was measured by using enzyme-linked immunosorbent assay technique.

RESULTS

The mean serum level of adropin was 12.32 ± 2.98 and 9.51 ± 2.73 in patients and control groups, respectively (p value < .001). Also, there were significant difference in frequency of genotypes and alleles of rs7903146 in patients and controls groups (p < .001). The rs7903146T/T and rs7903146C/T genotypes increased risk of T2DM disease (OR: 6.035 and OR: 3.082, respectively). Interestingly, the highest level of adropin was detected in T2DMpatients with rs7903146T/T genotype.

CONCLUSION

Our analysis showed higher level of adropin in T2DM patients and increased risk of T2DM with rs7903146T/T and rs7903146C/T genotypes.

Mechanical Stimulation Protects Against Chondrocyte Pyroptosis Through Irisin-Induced Suppression of PI3K/Akt/NF-κB Signal Pathway in Osteoarthritis

Irisin, a myokine secreted by muscle during physical exercise, is known to have biological activities in different cell types. Chondrocyte inflammation and pyroptosis have been shown to play important roles in osteoarthritis (OA). In this study, we investigated the effects of exercise-induced irisin during different intensities of treadmill exercise in a rat OA model and the anti-inflammatory and antipyroptosis mechanism of irisin in OA chondrocytes. Forty-eight SD rats (n = 8) were randomly assigned to control (CG), OA (OAG), OA groups under different intensities of treadmill exercise (OAL, OAM, and OAH), OAM + irisin neutralizing antibodies group (OAM + irisin (NA)). The levels of irisin and the severity of OA between groups were detected using ELISA, histology, immunohistochemistry, X-ray and computed tomography and magnetic resonance imaging. The anti-inflammatory and antipyroptosis mechanisms of irisin were investigated in vitro in OA chondrocytes preincubated with recombinant irisin (0, 5, or 10 ng/ml) for 1 h before treatment with interleukin-1β (IL-1β) for 24 h mRNA and protein expression levels were determined using quantitative reverse transcription polymerase chain reaction, and western blot analyses. Morphological changes and cell death associated with pyroptosis were examined using transmission electron microscopy, flow cytometry and immunofluorescence. Moderate-intensity treadmill exercise increased the levels of irisin, exhibiting the best therapeutic effects on OA which could be suppressed by irisin neutralizing antibodies. Irisin not only recovered the expression of collagen II and attenuated that of MMP-13 and ADAMTS-5 in IL-1β-induced OA chondrocytes by inhibiting the PI3K/Akt/NF-κB signaling pathway, but also inhibited the activity of nod-like receptor protein-3 (NLRP3)/caspase-1, thus ameliorating pyroptosis in chondrocytes. In conclusion, moderate mechanical stimulation protects against chondrocyte pyroptosis through irisin-induced suppression of PI3K/Akt/NF-κB signal pathway in osteoarthritis.

Circulating levels of adropin and overweight/obesity: a systematic review and meta-analysis of observational studies

The association between circulating adropin levels and overweight/obesity is currently unclear. The aim of this study was thus to investigate and seek to determine the association between circulating adropin levels and overweight/obesity using the meta-analysis approach of observational studies. A comprehensive literature search was carried out through the PubMed, Web of Science, and SCOPUS databases to identify relevant observational studies that assessed the relationship between circulating adropin levels and overweight/obesity up to September 2020. A random-effects model was used to compute the pooled weighted mean difference (WMD) with 95% confidence intervals (CI). The meta-analysis of five studies (n = 643 participants) showed that circulating adropin levels were significantly lower in the overweight/obese vs. the normal-weight participants (WMD =  - 0.96 ng/ml, 95% CI =  - 1.72 to - 0.19, P = 0.01; I² = 88.4%). In subgroup analyses, lower circulating adropin levels in obese participants compared with normal-weight were observed in Asians (WMD =  - 1.58 ng/ml, 95% CI =  - 1.96 to - 1.21, P < 0.001; I² = 0.00%), and in patients with metabolic disorders (WMD =  - 1.26 ng/ml, 95% CI =  - 1.76 to - 0.77, P < 0.001; I² = 44.6%), respectively. Circulating adropin levels were significantly lower in overweight/obese vs. normal-weight participants, suggesting a possible role of this hormone in the development of obesity. However, the present research indicates that further studies are needed to conclusively confirm whether adropin is a viable marker of obesity.

Review of Novel Potential Insulin Resistance Biomarkers in PCOS Patients—The Debate Is Still Open

Research on proteins and peptides that play roles in metabolic regulation, which may be considered potential insulin resistance markers in some medical conditions, such as diabetes mellitus, obesity and polycystic ovarian syndrome (PCOS), has recently gained in interest. PCOS is a common endocrine disorder associated with hyperandrogenemia and failure of ovulation, which is often accompanied by metabolic abnormalities, including obesity, dyslipidemia, hyperinsulinemia, and insulin resistance. In this review, we focus on less commonly known peptides/proteins and investigate their role as potential biomarkers for insulin resistance in females affected by PCOS. We summarize studies comparing the serum fasting concentration of particular agents in PCOS individuals and healthy controls. Based on our analysis, we propose that, in the majority of studies, the levels of nesfastin-1, myonectin, omentin, neudesin were decreased in PCOS patients, while the levels of the other considered agents (e.g., preptin, gremlin-1, neuregulin-4, xenopsin-related peptide, xenin-25, and galectin-3) were increased. However, there also exist studies presenting contrary results; in particular, most data existing for lipocalin-2 are inconsistent. Therefore, further research is required to confirm those hypotheses, as well as to elucidate the involvement of these factors in PCOS-related metabolic complications.

Myricetin Increases Circulating Adropin Level after Activation of Glucagon-like Peptide 1 (GLP-1) Receptor in Type-1 Diabetic Rats

Myricetin is a common plant-derived flavonoid, considered an agonist of glucagon-like peptide 1 (GLP-1) receptor. It improves glycemic control and helps reduce body weight in diabetic subjects. The potential mechanisms of action of myricetin in this context might be enhancing the secretion of β-endorphin (BER) to activate peripheral μ-opioid receptors. Moreover, adropin is a nutritionally regulated peptide hormone, which regulates energy metabolism, and plays a role in ameliorating diabetes. Because their mechanisms of insulin sensitivity are closely related, we hypothesized that myricetin may interact with adropin and plasma BER. The present study investigated the glucose-lowering effect of acute and chronic treatments of myricetin in type-1 diabetic rats. Plasma BER and adropin levels were determined by enzyme-linked immunosorbent assay (ELISA). The secretion of BER was measured in rats who received adrenalectomy. The changes in adropin gene (Enho) or mRNA level of GLP-1 receptor were measured using qPCR analysis. The results showed that myricetin dose-dependently increased plasma BER and adropin levels like the reduction of hyperglycemia after bolus injection as acute treatment. In addition, these effects of myricetin were inhibited by the antagonist of GLP-1 receptor. Moreover, in HepG2 cell line, myricetin induced GLP-1 receptor activation, which modulated the expression of adropin. In diabetic rats, the plasma adropin increased by myricetin is mainly through endogenous β-endorphin after activation of GLP-1 receptor via bolus injection as acute treatment. Additionally, chronic treatment with myricetin increased adropin secretion in diabetic rats. In conclusion, our results provide a new finding that activation of opioid μ-receptor in the liver may enhance circulating adropin in animals.

Irisin and Secondary Osteoporosis in Humans

Irisin is a peptide secreted by skeletal muscle following exercise that plays an important role in bone metabolism. Numerous experiments in vitro and in mouse models have shown that the administration of recombinant irisin promotes osteogenesis, protects osteocytes from dexamethasone-induced apoptosis, prevents disuse-induced loss of bone and muscle mass, and accelerates fracture healing. Although some aspects still need to be elucidated, such as the dose- and frequency-dependent effects of irisin in cell cultures and mouse models, ample clinical evidence is emerging to support its physiological relevance on bone in humans. A reduction in serum irisin levels, associated with an increased risk of osteoporosis and bone fractures, was observed in postmenopausal women and in both men and women during aging, Recently, cohort studies of subjects with secondary osteoporosis showed that these patients have lower circulating levels of irisin, suggesting that this myokine could be a novel marker to monitor bone quality in this disease. Although there are still few studies, this review discusses the emerging data that are highlighting the involvement of irisin in some diseases that cause secondary osteoporosis.

Expression of Circulating MicroRNAs and Myokines and Interactions with Serum Osteopontin in Type 2 Diabetic Patients with Moderate and Poor Glycemic Control: A Biochemical and Molecular Study

BACKGROUND

Cellular miRNAs are expressed in tissue fluids with sufficient amounts and were identified as potential molecular targets for studying the physiological mechanisms and correlations with many human diseases particularly diabetes. However, molecular-based changes among older adults with diabetes mellitus (DM) are rarely fully elucidated.

AIM

This study is aimed at identifying circulating miRNAs, which hold the potential to serve as biomarkers for the immune-inflammatory changes in older T2D patients with moderate and poor glycemic control status. In addition, the association of both myokines and osteopontin (OPN) levels with circulating miRNAs was identified.

METHODS

A total of 80 subjects aged 20-80 years were invited during the period of October 2017-May 2018 to participate in this descriptive cross-sectional study. All subjects were diagnosed with T2D for more than 5 years. Subjects were grouped based on glycemic control (HbA1c values) into two groups: moderate glycemic control (>7-8% HbA1c, no = 30) and poor glycemic control (>8% HbA1c, no = 50), respectively. Diabetic control parameters, fasting blood sugar (FS), HbA1c, fasting insulin (IF), insulin resistance (IR), HOMA-IR, inflammatory cytokines (IL-6, IL-8, IL-18, IL-23, TNF-α, and CRP), osteopontin, and myokines (adropin and irisin) were estimated by colorimetric and immune ELISA assays, respectively. In addition, real-time RT-PCR analysis was performed to evaluate the expression of circulating miRNAs, miR-146a and miR-144, in the serum of all diabetic subjects.

RESULTS

In this study, T2D patients with poor glycemic control showed a significant increase in the serum levels of IL-6, IL-8, IL-18, IL-23, TNF-α, CRP, and OPN and a reduction in the levels of myokines, adropin and irisin, compared to patients with moderate glycemic control. The results obtained are significantly correlated with the severity of diabetes measured by HbA1c, FS, IF, and HOMA-IR. In addition, baseline expression of miR-146a is significantly reduced and miR-144 is significantly increased in T2D patients with poor glycemic control compared to those with moderate glycemic control. In all diabetic groups, the expression of miR-146a and miR-144 is significantly correlated with diabetic controls, inflammatory cytokines, myokines, and serum levels of OPN. Respective of gender, women with T2D showed more significant change in the expressed miRNAs, inflammatory cytokines, OPN, and serum myokine markers compared to men. ROC analysis identified AUC cutoff values of miR-146a, miR-144, adropin, irisin, and OPN expression levels with considerable specificity and sensitivity which recommends the potential use of adropin, irisin, and OPN as diagnostic biomarkers for diabetes with varying glycemic control status.

CONCLUSION

In this study, molecular expression of certain microRNA species, such as miR-146a and miR-144, was identified and significantly associated with parameters of disease severity, HbA1c, inflammatory cytokines, myokines, and serum osteopontin in T2D patients with moderate and poor glycemic control. The AUC cutoff values of circulating miRNAs, miR-146a and miR-144; myokines, adropin and irisin; and serum OPN were significantly identified by ROC analysis which additionally recommends the potential use of these biomarkers, miR-146a, miR-144, adropin, irisin, and OPN, as diagnostic biomarkers with considerable specificity and sensitivity for diabetes in patients with varying glycemic control status.

Irisin Acts via the PGC-1α and BDNF Pathway to Improve Depression-like Behavior

Depression is the most prevalent psychiatric disorder experienced by the world's population. Mechanisms associated with depression-like behavior have not been fully investigated. Among the therapeutic solution for depression, exercise is considered an important regulator attenuating depressive neuropathology. Exercise has been reported to boost the secretion of myokines such as irisin and myostatin in skeletal muscles. Myokines secreted during exercise are involved in various cellular responses including the endocrine and autocrine systems. Especially, irisin as a cleaved version of fibronectin domain-containing protein 5 has multiple functions such as white fat-browning, energy expenditure increase, anti-inflammatory effects, and mitochondrial function improvement in both systemic circulation and central nervous system. Furthermore, irisin activates energy metabolism-related signaling peroxisome proliferator-activated receptor-gamma coactivator-1 alpha and memory formation-related signaling brain-derived neurotrophic factor involved in depression. However, the role and mechanism of irisin in depression disorder is not obvious until now. Here, we review recent evidences regarding the therapeutic effect of irisin in depression disorder. We suggest that irisin is a key molecule that suppresses several neuropathological mechanisms involved in depression.

Comparative Genomic Characterization of Buffalo Fibronectin Type III Domain Proteins: Exploring the Novel Role of FNDC5/Irisin as a Ligand of Gonadal Receptors

FN-III proteins are widely distributed in mammals and are usually involved in cellular growth, differentiation, and adhesion. The FNDC5/irisin regulates energy metabolism and is present in different tissues (liver, brain, etc.). The present study aimed to investigate the physiochemical characteristics and the evolution of FN-III proteins and FNDC5/irisin as a ligand targeting the gonadal receptors including androgen (AR), DDB1 and CUL4 associated factor 6 (DCAF6), estrogen-related receptor β (ERR-β), estrogen-related receptor γ (ERR-γ), Krüppel-like factor 15 (KLF15), and nuclear receptor subfamily 3 group C member 1 (NR3C1). Moreover, the putative role of irisin in folliculogenesis and spermatogenesis was also elucidated. We presented the molecular structure and function of 29 FN-III genes widely distributed in the buffalo genome. Phylogenetic analysis, motif, and conserved domain pattern demonstrated the evolutionary well-conserved nature of FN-III proteins with a variety of stable to unstable, hydrophobic to hydrophilic, and thermostable to thermo-unstable properties. The comparative structural configuration of FNDC5 revealed amino acid variations but still the FNDC5 structure of humans, buffalo, and cattle was quite similar to each other. For the first time, we predicted the binding scores and interface residues of FNDC5/irisin as a ligand for six representative receptors having a functional role in energy homeostasis, and a significant involvement in folliculogenesis and spermatogenesis in buffalo.

Irisin, Energy Homeostasis and Male Reproduction

Irisin is a novel skeletal muscle- and adipose tissue-secreted peptide. It is conventionally regarded as an adipomyokine and is a cleaved fragment of Fibronectin type III domain-containing protein 5 (FNDC5). It is involved in the browning of white adipose tissue, glucose tolerance, and reversing of metabolic disruptions. Fertility is closely linked to energy metabolism and the endocrine function of the adipose tissue. Moreover, there is established association between obesity and male infertility. Irisin bears strong therapeutic promise in obesity and its associated disorders, as well as shown to improve male reproductive functions. Thus, irisin is a molecule of great interest in exploring the amelioration of metabolic syndrome or obesity-induced male infertility. In this review we aim to enumerate the most significant aspects of irisin actions and discuss its involvement in energy homeostasis and male reproduction. Though current and future research on irisin is very promiscuous, a number of clarifications are still needed to reveal its full potential as a significant medicinal target in several human diseases including male infertility.

Irisin restores high glucose-induced cell injury in vascular endothelial cells by activating Notch pathway via Notch receptor 1

Diabetic foot ulcers (DFU) are a vascular complication of diabetes mellitus (DM). It has been confirmed that irisin is closely related to DM. However, the effect of irisin on DFU is obscure and needs further study. After human umbilical vein endothelial cell lines (HUVECs) were treated with different concentrations' irisin, normal glucose, high glucose (HG), HG plus irisin-high (H) or sh-Notch1, cell biological behaviors, LDH, and VEGFA were detected by cell function experiments. Apoptosis- and Notch pathway-related protein levels were evaluated by Western blot. Irisin has no cytotoxicity, and irisin-H elevated cell viability and inhibited apoptosis and LDH level in HG-induced HUVECs. Meanwhile, irisin-H restored HG-repressed migration and angiogenesis in HUVECs. Irisin-H inhibited apoptosis-related protein levels and promoted VEGFA and Notch pathway-related protein levels in HG-treated HUVECs. Additionally, sh-Notch1 reversed the protective effect of irisin-H in HG-treated HUVECs. Irisin restores HG-induced cell injury and angiogenesis in HUVECs by activating Notch pathway via Notch1.

Adropin and spexin hormones regulate the systemic inflammation in adenine-induced chronic kidney failure in rat

Chronic kidney disease is one of the major global health problems. Chronic renal failure is stimulated by many cytokines and chemokines. Adropin and spexin (SPX) are peptides hormones. These peptides could affect inflammatory conditions, but this is unclear. Due to the limited information, we planned to investigate the impact of adropin and SPX hormones on systemic inflammation in adenine induced chronic kidney failure rat model. Chronic kidney failure was induced by administering adenine hemisulfate. Renal functions were measured by an autoanalyzer. Granulocyte colony-stimulating factor (G-CSF), interferon-gamma (IFN-γ), interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-10, IL-12, IL-13, IL-17A, tumor necrosis factor-alpha, Eotaxin, growth-regulated oncogene-alpha, IP-10, monocyte chemoattractant protein (MCP)-1, MCP-3, macrophage inflammatory protein (MIP)-1α, MIP-2, and RANTES levels were determined by Luminex. We observed an increase in 24-h urine volume and serum creatinine. Blood urea nitrogen (BUN) and urine protein levels were also significantly higher in the chronic kidney failure (CKF) group. Urine protein and 24-h urine volume were reduced with adropin and SPX treatments. Furthermore, G-CSF, IFN-γ, IL-4, IL-5, IL-10, IL-12, IL-17A, and GRO-α significantly increased by CKF induction; however, these cytokines and chemokines significantly decreased by adropin treatment in the CKF group. Furthermore, adropin increased IP-10, MCP-1, MIP-1α, and MIP-2 levels. In addition, SPX treatment had a more limited effect, decreasing only G-CSF, IFN-γ, and IL-5 levels. The combined adropin + SPX treatment significantly reduced G-CSF, IFN-γ, IL-4, IL-5, IL-12, and IL-17A. Furthermore, IP-10, MCP-1, MCP-3, and MIP-2 were significantly increased by these combined treatments. Our findings indicate that renal functions and inflammatory response were modulated by adropin and SPX peptides. These peptides may have protective effects on systemic inflammation and renal failure progression.

Inflammatory response and matrix metalloproteinases in chronic kidney failure: Modulation by adropin and spexin

Chronic kidney disease is a major global public health problem. The peptide hormones adropin and spexin modulate many physiological functions such as energy balance and glucose, lipid and protein metabolism. However, it is unclear whether these peptides may exert effects on renal damage, tissue remodeling, and inflammatory conditions. In view of the limited information, we aimed to investigate the effect of adropin and spexin on matrix metalloproteinase and inflammatory response genes a rat model of adenine-induced chronic kidney failure. Chronic kidney failure was induced in rats by administering adenine hemisulfate. Renal function was determined in an autoanalyzer. Histopathological modifications were assessed by H&E staining. mRNA expression levels of ALOX 15, COX 1, COX 2, IL-1β, IL-10, IL-17A, IL-18 IL-21, IL-33, KIM-1, MMP-1, MMP-2, MMP-3, MMP-7, MMP-9, MMP-13, NGAL, TGFβ1, TIMP-1, and TNFα in kidney tissue were measured by qPCR. Our results showed an increase of 24-h urine volume, serum creatinine, BUN, and urine protein levels in group with adenine-induced CKF. Adropin and spexin treatments decreased urine protein and 24-h urine volume. Renal damage, TIMP-1, IL-33, and MMP-2 increased after CKF induction, while COX 1, MMP-9, and MMP-13 levels were significantly reduced. Furthermore, KIM-1, TIMP-1, IL-33, and MMP-2 were downregulated by spexin treatment. Renal damage, NGAL, TIMP-1 IL-17A, IL-33, MMP-2, and MMP-3 decreased after adropin treatment, while MMP-13 levels were upregulated. Treatment with adropin+spexin decreased KIM-1, NGAL, TIMP-1, IL-1β, IL-17A, IL-18, IL-33, ALOX 15, COX 1, COX 2, TGFβ1, TNFα, MMP-2, MMP-3, and MMP-7, but increased MMP-13 levels. Our findings revealed that inflammatory response and MMP genes were modulated by adropin and spexin. These peptides may have protective effects on inflammation and chronic kidney damage progression.

Adropin Serum Levels in Patients with Primary Sjögren's Syndrome

Primary Sjögren’s syndrome (pSS) patients have higher prevalence of endothelial dysfunction and premature atherosclerosis. Recent studies investigated adropin, a secretory protein that can regulate lipid metabolism and insulin resistance and protect endothelial cells’ function and that has an anti-inflammatory effect. The aim of this study was to determine adropin levels in pSS patients compared to healthy controls. Additional goals were exploring the correlation between adropin and several metabolic and immunological parameters in pSS, including disease specific antibodies, EULAR Sjögren’s Syndrome Disease Activity Index (ESSDAI), and Sjögren’s Syndrome Disease Damage Index (SSDDI). This research included 52 pSS patients and 52 healthy controls. pSS patients have significantly higher adropin levels compared to the control group (3.76 ± 0.68 vs. 3.14 ± 0.69 ng/mL, p < 0.001). Correlation analysis showed that adropin levels in pSS patients have positive correlation with high-density lipoprotein (HDL) (r = 0.290, p = 0.036) and anti SSA/Ro52 antibodies (r = 0.307, p = 0.026) and negative correlation with SSDDI (r = −0.401, p = 0.003). Multivariant linear regression showed that adropin levels are independently associated with HDL (β ± SE, 0.903 ± 0.283, p = 0.002) and SSDDI (β ± SE, −0.202 ± 0.073, p = 0.008). Our findings imply that adropin could be involved in the pathophysiology of pSS, yet it remains to be elucidated in future studies whether adropin has a protective or detrimental role in this setting.

The Regulatory Role of Different Exercises in Irisin, Heat Shock Protein 70 and Some Biochemical Parameters

Background

The aim of the study was to determine the effects of different and regularly applied exercise programs on irisin, heat shock protein 70 and some biochemical parameters.

Methods

120 male university students participated in the study. Participants were divided into 4 equal groups as control (C), resistance exercise group (RE), high intensity interval (HIIT) and aerobic exercise group (AE). While the control group did not perform any exercise, the pre-determined exercise programs were applied to the other groups for 8 weeks and 3 days in a week. Blood samples were taken from all participants before and after the exercise program. Cholesterol, High-density Lipoprotein (HDL) and Low-density Lipoprotein (LDL) cholesterol, triglyceride (TG), Creatine kinase (CK), Lactate dehydrogenase (LDH), Irisin and Heat shock protein 70 (HSP70) levels were analyzed in blood samples.

Results

It is determined that there are significant differences in pre-posttest values of the AE group's LDH, cholesterol, HDL-cholesterol, TG and HSP 70 levels, HIIT group's CK, LDH, Cholesterol, HDL-cholesterol, TG, Irisin and HSP70 levels and RE group's CK, LDH, Cholesterol, LDL-cholesterol, TG and Irisin levels (p<0.05).

Conclusions

It can be said that exercise can provide improvements in lipid profile, changes in HSP70 levels may vary depending on muscle damage, the increase of irisin due to exercise.

Cardiometabolic Effects of Irisin in Patients with End-Stage Renal Disease on Regular Hemo- or Peritoneal Dialysis

INTRODUCTION

Data on the role of irisin in vascular calcification in patients with end-stage renal diseases on regular dialysis are inconsistent, and the underlying mechanisms are not clearly defined. The present study was designed to explore the association of serum irisin with vascular stiffness and with the impact of well-established risk factors.

METHODS

The clinical study enrolled 52 hemodialysis (HD) and 15 continuous ambulatory peritoneal dialysis (PD) patients with an age of >18 years receiving dialysis therapy for >3 months. Patients who had major pathologies affecting carbohydrate, lipid, and bone metabolism and those who had acute cardiovascular events were excluded. Thirty-seven healthy subjects matched for age and sex served as controls. Routine biochemical parameters were measured in fasting serum samples by standard methods. Serum irisin was determined using the commercial ELISA kit (BioVendor Laboratory Medicine Inc., Brno, Czech Republic). Arterial stiffness parameters - carotid-femoral pulse wave velocity (cf PWV) and augmentation index (Aix) - were measured using applanation tonometry (SphygmoCor System; AtCor Medical, Sydney, Australia). Body composition was assessed by segmental bioelectric impedance (InBody 2.0; Biospace Co. Ltd., Seoul, Korea).

RESULTS

It was demonstrated that serum irisin levels were markedly depressed (p < 0.05), while the cf PWV significantly increased (p < 0.05) in HD/PD patients as compared to controls. Serum irisin proved to be independent of serum insulin, glucose, and HOMA-IR. However, it was inversely related to HbA1c (β = -0.544, p = 0.035), iPTH (β = -0.260, p = 0.035), and alkaline phosphatase (r = -0.325, p = 0.007). Furthermore, significant negative relationships were found of irisin to serum triglyceride and indices of body fat mass. Retrospective analysis at a follow-up period of 40 months revealed a direct relationship of irisin to all-cause mortality (p = 0.039).

CONCLUSIONS

Our study demonstrated that serum irisin levels are reduced in uremic patients on regular HD/PD but failed to establish significant associations of irisin deficiency with vascular stiffness. However, the significant negative relationship of irisin to HbA1c, iPTH, and alkaline phosphatase suggests that it improves insulin sensitivity, inhibits bone resorption, mitigates bone-vascular interaction, and protects vascular function.

FNDC5/Irisin attenuates diabetic cardiomyopathy in a type 2 diabetes mouse model by activation of integrin αV/β5-AKT signaling and reduction of oxidative/nitrosative stress

Irisin, the cleaved form of the fibronectin type III domain containing 5 (FNDC5) protein, is involved in metabolism and inflammation. Recent findings indicated that irisin participated in cardiovascular physiology and pathology. In this study, we investigated the effects of FNDC5/irisin on diabetic cardiomyopathy (DCM) in type 2 diabetic db/db mice. Downregulation of myocardial FNDC5/irisin protein expression and plasma irisin levels was observed in db/db mice compared to db/+ controls. Moreover, echocardiography revealed that db/db mice exhibited normal cardiac systolic function and impaired diastolic function. Adverse structural remodeling, including cardiomyocyte apoptosis, myocardial fibrosis, and cardiac hypertrophy were observed in the hearts of db/db mice. Sixteen-week-old db/db mice were intramyocardially injected with adenovirus encoding FNDC5 or treated with recombinant human irisin via a peritoneal implant osmotic pump for 4 weeks. Both overexpression of myocardial FNDC5 and exogenous irisin administration attenuated diastolic dysfunction and cardiac structural remodeling in db/db mice. Results from in vitro studies revealed that FNDC5/irisin protein expression was decreased in high glucose (HG)/high fat (HF)-treated cardiomyocytes. Increased levels of inducible nitric oxide synthase (iNOS), NADPH oxidase 2 (NOX2), 3-nitrotyrosine (3-NT), reactive oxygen species (ROS), and peroxynitrite (ONOO^-) in HG/HF-treated H9C2 cells provided evidence of oxidative/nitrosative stress, which was alleviated by treatment with FNDC5/irisin. Moreover, the mitochondria membrane potential (ΔΨm) was decreased and cytochrome C was released from mitochondria with increased levels of cleaved caspase-3 in HG/HF-treated H9C2 cells, indicating the presence of mitochondria-dependent apoptosis, which was partially reversed by FNDC5/irisin treatment. Mechanistic studies showed that activation of integrin αVβ5-AKT signaling and attenuation of oxidative/nitrosative stress were responsible for the cardioprotective effects of FNDC5/irisin. Therefore, FNDC5/irisin mediates cardioprotection in DCM by inhibiting myocardial apoptosis, myocardial fibrosis, and cardiac hypertrophy. These findings implicate that FNDC5/irisin as a potential therapeutic intervention for DCM, especially in type 2 diabetes mellitus (T2DM).

Two weeks of moderate intensity locomotor training increased corticosterone concentrations but did not alter the number of adropin-immunoreactive cells in the hippocampus of diabetic type 2 and control rats

Adropin (ADR) plays a role in metabolism regulation and its alterations in obesity and diabetes have been found. Treatment with ADR was beneficial in metabolic diseases, and physical exercise increased ADR concentrations in obese patients. However, data on the distribution of ADR in the brain are sparse. The role of metabolic status and physical exercise on its expression in the brain is undiscovered. We hypothesized that diabetes type 2 (DM2) and/or exercise will alter number of ADR-immunoractive (-ir) cells in the rat brain. Animals were divided into groups: diabetes type 2 (receiving high-fat diet and injections of streptozotocin) and control (fed laboratory chow diet; C). Rats were further divided into: running group (2 weeks of forced exercise on a treadmill) and non-running group. Body mass, metabolic and hormonal profiles were assessed. Immunohistochemistry was run to study ADR-ir cells in the brain. We found that: 1) in DM2 animals, running decreased insulin and increased glucose concentrations; 2) in C rats, running decreased insulin concentrations and had no effect on glucose concentration in blood; 3) running increased corticosterone (CORT) concentrations in DM2 and C rats; 4) ADR-ir cells were detected in the hippocampus and ADR-ir fibers in the arcuate nucleus of the hypothalamus, which is a novel location; 5) metabolic status and running, however, did not change number of these cells. We concluded that 2 weeks of forced moderate intensity locomotor training induced stress response present as increased concentration of CORT and did not influence number of ADR-ir cells in the brain.

Exercise in the cold causes greater irisin release but may not be enough for adropin

When irisin and adropin were discovered, it was popularly hoped that they would become therapies for metabolic disorders that threaten global health. However, contradictory results have been reported in the subsequent period. Irisin, induced by exercise or cold exposure, is believed to be a myokine that causes the browning of adipose tissue thus increasing energy expenditure. Adropin is thought to be beneficial for health by regulating blood flow, capillary density, and playing an active role in glucose and insulin homeostasis. However, there were no experimental studies investigating the simultaneous effect of exercise and cold exposure in humans. The purpose of this study was to investigate irisin and adropin responses in young healthy individuals performing aerobic exercise in different environmental temperatures. Twenty-seven young, healthy individuals participated in this study. Participants performed 40 min of aerobic running exercise in environmental temperatures of 0°C, 12°C, and 24°C. Venous blood samples were taken pre- and post-exercise. Irisin and adropin levels were analyzed using an enzyme-linked immunosorbent assay. The principal findings showed that while serum irisin concentrations significantly increased after aerobic exercise was performed at an environmental temperature of 0°C, there was no significant difference between pre- and post-exercise recordings for physical activity performed at 12°C and 24°C. Adropin concentrations, however, remained unchanged between pre- and post-exercise at 0°C, 12°C, and 24°C. Interestingly, the exercise at 0°C caused an increase in adropin (12.5%), but this amount was not enough to be a statistically significant result. The findings of this study suggest that aerobic exercise in a cold environment causes greater irisin release. However, the combined effect of exercise and cold exposure may not be enough to statistically increase adropin level.

Evaluation of salusin-α and salusin-β levels in patients with type 2 diabetes mellitus and determination of the impact of severity of hyperglycemia on salusin levels

AIMS

To investigate the usefulness of salusin-α and salusin-β as biomarkers in patients with type 2 diabetes mellitus (T2DM) and to determine whether diabetes severity and obesity have an effect on the salusin levels in diabetic patients.

METHODS

The study included a total of 90 patients, comprising 55 diagnosed with T2DM and 35 healthy volunteers with similar demographic characteristics. Salusins were assayed by a commercially available ELISA kit.

RESULTS

The salusin-β levels were found to be significantly higher in T2DM group compared to control group, while the salusin-α levels were lower (p < 0.05, for both). Furthermore, in patient group, Spearman analysis showed a statistically significant negative correlation between salusin-α and fasting glucose and glycated hemoglobin (HbA1c), whereas salusin-β had a statistically significant positive correlation with fasting glucose and HbA1c (p < 0.05, for both). When analyzed according to the HbA1c groups, the patients with HbA1c > 9% had significantly lower salusin-α and higher salusin-β levels levels compared to those with HbA1c < 9% (p < 0.05, for both). When examined according to body-mass-index groups, there was no significant difference in the salusin levels of the patient and control groups (p > 0.05).

CONCLUSION

We demonstrated that the serum salusin-α level was decreased whereas the salusin-β level was increased in patients with T2DM compared to healthy subjects, and this was more pronounced as T2DM-deteriorated. We also showed that obesity had no effect on salusin levels among diabetics. This study may provide a basis for the availability of salusin-targeted therapies, especially in uncontrolled T2DM.

Adropin-based dual treatment enhances the therapeutic potential of mesenchymal stem cells in rat myocardial infarction

Both weak survival ability of stem cells and hostile microenvironment are dual dilemma for cell therapy. Adropin, a bioactive substance, has been demonstrated to be cytoprotective. We therefore hypothesized that adropin may produce dual protective effects on the therapeutic potential of stem cells in myocardial infarction by employing an adropin-based dual treatment of promoting stem cell survival in vitro and modifying microenvironment in vivo. In the current study, adropin (25 ng/ml) in vitro reduced hydrogen peroxide-induced apoptosis in rat bone marrow mesenchymal stem cells (MSCs) and improved MSCs survival with increased phosphorylation of Akt and extracellular regulated protein kinases (ERK) l/2. Adropin-induced cytoprotection was blocked by the inhibitors of Akt and ERK1/2. The left main coronary artery of rats was ligated for 3 or 28 days to induce myocardial infarction. Bromodeoxyuridine (BrdU)-labeled MSCs, which were in vitro pretreated with adropin, were in vivo intramyocardially injected after ischemia, following an intravenous injection of 0.2 mg/kg adropin (dual treatment). Compared with MSCs transplantation alone, the dual treatment with adropin reported a higher level of interleukin-10, a lower level of tumor necrosis factor-α and interleukin-1β in plasma at day 3, and higher left ventricular ejection fraction and expression of paracrine factors at day 28, with less myocardial fibrosis and higher capillary density, and produced more surviving BrdU-positive cells at day 3 and 28. In conclusion, our data evidence that adropin-based dual treatment may enhance the therapeutic potential of MSCs to repair myocardium through paracrine mechanism via the pro-survival pathways.

Irisin Has a Protective Role against Osteoporosis in Ovariectomized Rats

The reduction in estrogen levels results in a decrease in bone density at menopause. Irisin is a myokine that modulates the benefits of exercise, which may include bone health. This study was planned to examine irisin's impact in preventing osteoporosis after ovariectomy. 4 groups of female albino rats (10 rats/group): control, sham-operated, ovariectomized (OVX-control), and OVX-irisin-treated. Serum levels of bone markers [osteocalcin (OC), bone alkaline phosphatase (BALP), tartrate-resistant acid phosphatase (TRAP), calcium (Ca⁺⁺), phosphorus (P)], glucose, and insulin were being measured. Body mass index, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), dry and ash femur weight, and bone contents of Ca⁺⁺ and P were investigated. The femur was examined histopathologically. The OVX-control group showed an increase in serum levels of OC, BALP, TRAP, calcium, phosphorus, BMI, glucose, insulin, and HOMA-IR (P < 0.05) and a reduction in dry and ash weight of the femur, the concentration of calcium and phosphorus content in bone ash (P < 0.05). The OVX-irisin-treated group exhibited a decrease in serum levels of OC, BALP and TRAP, calcium, phosphorus, BMI, glucose, insulin, HOMA-IR (P < 0.05), and a rise in dry and ash weight of the femur, the concentration of calcium and phosphorus in bone ash (P < 0.05). Histological examination of the distal femur diaphysis of the OVX-irisin-treated group exhibited proper bone architecture and density compared with that of the OVX-control group. It is concluded that irisin treatment in the OVX rats safeguarded the regular bone architecture and normal levels of serum bone biomarkers. Irisin may be a possible novel target in the prohibition of postmenopausal osteoporosis.

High-Intensity Interval vs. Continuous Endurance Training: Preventive Effects on Hormonal Changes and Physiological Adaptations in Prediabetes Patients

ABSTRACT

Safarimosavi, S, Mohebbi, H, and Rohani, H. High-intensity interval vs. continuous endurance training: Preventive effects on hormonal changes and physiological adaptations in prediabetes patients. J Strength Cond Res 35(3): 731-738, 2021-The aim of this study was to examine the effects of a 12-week high-intensity interval training (HIIT) intervention, or an isocaloric continuous endurance training (CET) intervention on insulin resistance indices and change in irisin and preptin in patients with prediabetes. Thirty-two prediabetic male patients (age = 38.7 ± 4; body mass index = 26.9 ± 1.4 kg·m-2; and V̇o2peak = 2.49 ± 0.22 L·min-1) were randomly assigned into 3 training groups (N = 8). These groups were matched based on the required energy expenditure (EE) for completing each protocol: (a) HIIT (10 × 60 seconds at 90% peak oxygen uptake [V̇o2peak], 1: 1 work to recovery at 50 W), (b) CET at an intensity equivalent to maximal fat oxidation (Fatmax) (CETFAT) (pedaling for a duration that expends an equivalent EE to an HIIT session [E ≈ HIIT]), (c) CET at an intensity equivalent to anaerobic threshold (CETAT) (E ≈ HIIT), and (d) the control group (CON): continued to perform their daily activities. After intervention, blood glucose levels were significantly (p < 0.05) lower in the HIIT group compared with CETAT group. Exercise training improved the insulin resistance index by 35, 28, and 37% in CETFAT, CETAT, and HIIT groups, respectively. Irisin concentrations in the HIIT and CETAT groups was significantly (p < 0.05) decreased compared with the pre-training values. Also, HIIT and CETFAT resulted in significant (p < 0.05) changes in preptin concentration compared with baseline. This study demonstrated that both HIIT and CETFAT protocols had similar effects on the insulin resistance index of prediabetic patients. Also, the intensity and type of exercise were effective factors in changing irisin and preptin concentrations.

Serum Adropin Levels in Patients on Hemodialysis

Adropin is a novel pleotropic peptide involved in energy homeostasis, with possible contribution to cardiovascular protection through production of nitric oxide and subsequent blood pressure regulation. Given that patients undergoing hemodialysis (HD) are related with high cardiovascular risk, hyperlipidemia, chronic low-grade inflammation, and malnutrition the aim of our study was to investigate serum adropin levels in HD patients to evaluate possible associations with nutritional status and other relevant clinical and laboratory parameters. The study included 70 patients on HD and 60 healthy controls. Serum adropin levels were determined by an enzyme-linked immunosorbent assay in a commercially available diagnostic kit. Serum adropin levels were significantly lower in the HD group compared to the control group (2.20 ± 0.72 vs. 4.05 ± 0.93 ng/mL, p < 0.001). Moreover, there was a significant negative correlation with malnutrition-inflammation score (r = −0.476, p < 0.001), dialysis malnutrition score (r = −0.350, p = 0.003), HD duration (r = −0.305, p = 0.010), and high sensitivity C-reactive protein (hsCRP) (r = −0.646, p < 0.001). Additionally, there was a significant negative correlation between adropin levels and pre-dialysis systolic (r = −0.301, p = 0.011) and diastolic blood pressure (r = −0.299, p = 0.011). These results are implying that adropin is potentially involved in the pathophysiological mechanisms of chronic kidney disease (CKD)/HD and its complications. However, future larger scale longitudinal studies need to further address it.

Irisin and Incretin Hormones: Similarities, Differences, and Implications in Type 2 Diabetes and Obesity

Incretins are gut hormones that potentiate glucose-stimulated insulin secretion (GSIS) after meals. Glucagon-like peptide-1 (GLP-1) is the most investigated incretin hormone, synthesized mainly by L cells in the lower gut tract. GLP-1 promotes β-cell function and survival and exerts beneficial effects in different organs and tissues. Irisin, a myokine released in response to a high-fat diet and exercise, enhances GSIS. Similar to GLP-1, irisin augments insulin biosynthesis and promotes accrual of β-cell functional mass. In addition, irisin and GLP-1 share comparable pleiotropic effects and activate similar intracellular pathways. The insulinotropic and extra-pancreatic effects of GLP-1 are reduced in type 2 diabetes (T2D) patients but preserved at pharmacological doses. GLP-1 receptor agonists (GLP-1RAs) are therefore among the most widely used antidiabetes drugs, also considered for their cardiovascular benefits and ability to promote weight loss. Irisin levels are lower in T2D patients, and in diabetic and/or obese animal models irisin administration improves glycemic control and promotes weight loss. Interestingly, recent evidence suggests that both GLP-1 and irisin are also synthesized within the pancreatic islets, in α- and β-cells, respectively. This review aims to describe the similarities between GLP-1 and irisin and to propose a new potential axis-involving the gut, muscle, and endocrine pancreas that controls energy homeostasis.

Irisin Protects Against Hind Limb Ischemia Reperfusion Injury

Aim

The aim of this study was to evaluate the effects of irisin in a murine model of hind limb ischemia reperfusion (I/R).

Methods

The mice were divided into four groups (n = 6 in each group): control, irisin, ischemia reperfusion (I/R), and irisin-ischemia reperfusion (I-I/R). Irisin (0.5 µg.g^-1, intraperitoneally [i.p.]) was administered 30 min before the I/R procedure. After 2 h of ischemia and 2.5 h of reperfusion, blood and tissue samples were taken for biochemical and histopathological analysis. The results were analyzed by Kruskal-Wallis and Mann-Whitney U-tests.

Results

There was a statistically significant difference in the total antioxidant status (TAS) and total oxidant status (TOS) levels in all the groups. The TAS level in the I/R group was significantly lower than that in the control, irisin, and I-I/R groups, whereas the TOS level was significantly higher in the I/R group as compared with that in the other groups. Caspase-3 activity and caspase-8 activity, indicators of inflammation, were significantly higher in the I/R and I-I/R groups as compared with those in the control and irisin groups.

Conclusion

Irisin may have protective effects in skeletal muscle ischemia reperfusion injury.

Organ-organ communication: The liver's perspective

Communication between organs participates in most physiological and pathological events. Owing to the importance of precise coordination among the liver and virtually all organs in the body for the maintenance of homeostasis, many hepatic disorders originate from impaired organ-organ communication, resulting in concomitant pathological phenotypes of distant organs. Hepatokines are proteins that are predominantly secreted from the liver, and many hepatokines and several signaling proteins have been linked to diseases of other organs, such as the heart, muscle, bone, and eyes. Although liver-centered interorgan communication has been proposed in both basic and clinical studies, to date, the regulatory mechanisms of hepatokine production, secretion, and reciprocation with signaling factors from other organs are obscure. Whether other hormones and cytokines are involved in such communication also warrants investigation. Herein, we summarize the current knowledge of organ-organ communication phenotypes in a variety of diseases and the possible involvement of hepatokines and/or other important signaling factors. This provides novel insight into the underlying roles and mechanisms of liver-originated signal transduction and, more importantly, the understanding of disease in an integrative view.

Myokines and Heart Failure: Challenging Role in Adverse Cardiac Remodeling, Myopathy, and Clinical Outcomes

Heart failure (HF) is a global medical problem that characterizes poor prognosis and high economic burden for the health system and family of the HF patients. Although modern treatment approaches have significantly decreased a risk of the occurrence of HF among patients having predominant coronary artery disease, hypertension, and myocarditis, the mortality of known HF continues to be unacceptably high. One of the most important symptoms of HF that negatively influences tolerance to physical exercise, well-being, social adaptation, and quality of life is deep fatigue due to HF-related myopathy. Myopathy in HF is associated with weakness of the skeletal muscles, loss of myofibers, and the development of fibrosis due to microvascular inflammation, metabolic disorders, and mitochondrial dysfunction. The pivotal role in the regulation of myocardial and skeletal muscle rejuvenation, attenuation of muscle metabolic homeostasis, and protection against ischemia injury and apoptosis belongs to myokines. Myokines are defined as a wide spectrum of active molecules that are directly synthesized and released by both cardiac and skeletal muscle myocytes and regulate energy homeostasis in autocrine/paracrine manner. In addition, myokines have a large spectrum of pleiotropic capabilities that are involved in the pathogenesis of HF including cardiac remodeling, muscle atrophy, and cardiac cachexia. The aim of the narrative review is to summarize the knowledge with respect to the role of myokines in adverse cardiac remodeling, myopathy, and clinical outcomes among HF patients. Some myokines, such as myostatin, irisin, brain-derived neurotrophic factor, interleukin-15, fibroblast growth factor-21, and growth differential factor-11, being engaged in the regulation of the pathogenesis of HF-related myopathy, can be detected in peripheral blood, and the evaluation of their circulating levels can provide new insights to the course of HF and stratify patients at higher risk of poor outcomes prior to sarcopenic stage.

Identification of a TMEM182 rs141764639 polymorphism associated with central obesity by regulating tumor necrosis factor-α in a Korean population

AIMS

To investigate the effect of a single nucleotide polymorphism (SNP) in transmembrane protein 182 (TMEM182) on the risk of having central obesity and the related phenotype.

METHODS

In total, 2141 subjects with central obesity (n = 827) and normal controls (n = 1314) were included. The most strongly associated SNPs were related to waist circumference, and one SNP, rs141764639, was identified in TMEM182 (p = 7.30E-06, q = 0.0326).

RESULTS

The TC genotype was associated with more central obesity; higher levels of blood pressure, glucose-related parameters, and inflammatory markers; abnormal lipid profiles; and smaller LDL particle sizes than the major allele homozygotes in the total population. TNF-α in the TC genotype showed extremely high levels compared to the TT genotype. There were significant interactions between the genotypes and waist circumference in relation to LDL particle size, TNF-α level, and IL-6 level. Compared with the reference group, the odds ratio for central obesity in C allele carriers was significantly increased by 2-fold.

CONCLUSIONS

The polymorphism of TMEM182 rs141764639 might have an effect on the incidence of central obesity in the Korean population by interacting with the upregulation of TNF-α, a proinflammatory cytokine. Moreover, LDL particle size, which is an atherogenic lipid profile trait, was associated with the TMEM182 rs141764639 genotype.