The Impact of Organokines on Insulin Resistance, Inflammation, and Atherosclerosis

A Novel "Endocrine Hormone": The Diverse Role of Extracellular Vesicles in Multiorgan Insulin Resistance

Insulin resistance is the primary contributor to the disruption in glucose homeostasis in the body, playing a significant causative role in many metabolic diseases. Insulin resistance is characterized by compensatory insulin secretion and reduced insulin responsiveness in target organs. Dysregulation of the interaction between insulin-secreting cells and insulin-responsive target organs is an important factor driving the progression of insulin resistance. Circulating endocrine hormones are important mediators mediating the interaction between insulin-secreting cells and insulin-responsive target organs. In addition to the classical hormones secreted by endocrine glands and organ-specific hormones secreted by metabolism-related organs (adipose tissue, muscle, liver, etc.), extracellular vesicles have been recognized as a novel class of endocrine hormones with a complex composition. Extracellular vesicles can transport signaling molecules, such as miRNAs and LncRNAs, to vital organs related to insulin resistance, in a manner akin to conventional hormones. The significant role in regulating the development of insulin resistance underscores the increasing interest in extracellular vesicles as essential contributors to this process. In this review, we summarize the three types of hormones (classical hormones, organokines and extracellular vesicles) that play a regulatory role in insulin resistance, and focus on the novel endocrine hormones, extracellular vesicles, to elaborate the mechanism of extracellular vesicles' regulation of insulin resistance progress from two aspects: the impact on insulin-secreting cells and the influence on insulin-responsive target organs. In addition, this paper outlines the clinical applications of extracellular vesicles in insulin resistance. A comprehensive understanding of the regulatory mechanisms and diagnostic status of the inter-organ network in insulin resistance has great potential to advance targeted therapeutic interventions and diagnostic markers, thereby benefiting both the prevention and treatment of insulin resistance.

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.

Current status and future perspectives of FGF21 analogues in clinical trials

Recent advances in fibroblast growth factor 21 (FGF21) biology and pharmacology have led to the development of several long-acting FGF21 analogues and antibody-based mimetics now in various phases of clinical trials for the treatment of obesity-related metabolic comorbidities. The efficacy of these FGF21 analogues/mimetics on glycaemic control and weight loss is rather mild and inconsistent; nevertheless, several promising therapeutic benefits have been reproducibly observed in most clinical studies, including amelioration of dyslipidaemia (particularly hypertriglyceridaemia) and hepatic steatosis, reduction of biomarkers of liver fibrosis and injury, and resolution of metabolic dysfunction-associated steatohepatitis (MASH). Evidence is emerging that combination therapy with FGF21 analogues and other hormones (such as glucagon-like peptide 1; GLP-1) can synergise their pharmacological benefits, thus maximising the therapeutic efficacy for obesity and its comorbidities.

The Significance of Selected Myokines in Predicting the Length of Rehabilitation of Patients after COVID-19 Infection

In the context of the global COVID-19 pandemic, understanding the intricate mechanisms of the body's response to infection and inflammation has become a priority for the medical and research communities. It has been proven that during COVID-19 infection, molecules are secreted-namely organokines, which may directly or indirectly play a role in the pathophysiology of COVID-19. The objective of this study was to scrutinize the potential correlation between the levels of selected myokines (myostatin, agrin, irisin, and myonectin) and the duration of rehabilitation in post-COVID-19 patients. Additionally, the study aimed to investigate whether there is a correlation between the levels of these myokines and the length of hospitalization during COVID-19 treatment. The study was conducted at the Rehabilitation Hospital in Szczecin (Poland). Patients in the study participated in a comprehensive rehabilitation program following COVID-19 treatment. In order to assess the effectiveness of rehabilitation, the following tests were performed: a 6 min walk test with an assessment of exercise tolerance (Borg scale), an assessment of dyspnea severity (mMRC scale), a spirometric assessment of respiratory function, a measurement of arm strength, and an assessment of fatigue using the Fatigue Assessment Scale (FAS). Myokine levels were measured using commercially available enzyme-linked immunosorbent assays (ELISA) according to the manufacturer's instructions. Statistical analysis was performed using Statistica 13.1 software. Lower concentrations of irisin and myonectin and higher concentrations of myostatin correlated with longer rehabilitation time. Baseline levels of specific myokines in post-COVID-19 patients could play a crucial role in anticipating the duration of rehabilitation. The duration of hospitalization for the infection may influence myokine levels in patients recovering from COVID-19.

Cardiometabolic diseases and early cognitive decline: Mitigated by integrated active lifestyle for brain health

BACKGROUND

Cardiometabolic diseases (CMDs) increases the risk of cognitive decline, but the extent to which this can be offset by adherence to an active integrated lifestyle is unknown.

METHODS

This prospective study used the baseline and 2-year follow-up data of 2537 dementia-free elderly ≥60 from PINDEC Project. Lifestyle factors (including physical exercise, social interaction, leisure activities, sleep quality, smoking, and alcohol consumption) were collected and the integrated score was calculated. Participants were divided into three groups based on integrated score tertiles (inactive, ≤3 score; intermediate, 4 score; and active, ≥5). Logistic regression was used in data analysis.

RESULTS

35.2 % participants had 5-6 healthy components, while only 5.4 % had all 6 healthy lifestyles. The multiadjusted odds ratios (ORs, 95 % confidence interval) of early cognitive decline was 1.223 (0.799-1.871) and 1.832 (1.140-2.943) for participants with only one CMD and any two or more CMDs, respectively. An inverse dose-response relationship was found between lifestyle scores and early cognitive decline (Ptrend = 0.017). In participants with active lifestyle, the OR for early cognitive decline comparing the CMDs status of any two or more CMDs vs. CMDs-free was 0.778 (95%CI: 0.302-2.007). Participants with inactive lifestyle and any two or more CMDs had a near 3.4-fold increased risk of early cognitive decline than those without CMDs who had intermediate to active lifestyle (OR = 3.422, 95%CI: 1.764-6.638).

LIMITATIONS

Our research lacks information about nutrition.

CONCLUSIONS

A dose-response relationship exists between CMDs status and risk of early cognitive decline. However, adherence to an active integrated lifestyle may mitigate this risk.

The pan-liver network theory: From traditional chinese medicine to western medicine

In traditional Chinese medicine (TCM), the liver is the "general organ" that is responsible for governing/maintaining the free flow of qi over the entire body and storing blood. According to the classic five elements theory, zang-xiang theory, yin-yang theory, meridians and collaterals theory, and the five-viscera correlation theory, the liver has essential relationships with many extrahepatic organs or tissues, such as the mother-child relationships between the liver and the heart, and the yin-yang and exterior-interior relationships between the liver and the gallbladder. The influences of the liver to the extrahepatic organs or tissues have been well-established when treating the extrahepatic diseases from the perspective of modulating the liver by using the ancient classic prescriptions of TCM and the acupuncture and moxibustion. In modern medicine, as the largest solid organ in the human body, the liver has the typical functions of filtration and storage of blood; metabolism of carbohydrates, fats, proteins, hormones, and foreign chemicals; formation of bile; storage of vitamins and iron; and formation of coagulation factors. The liver also has essential endocrine function, and acts as an immunological organ due to containing the resident immune cells. In the perspective of modern human anatomy, physiology, and pathophysiology, the liver has the organ interactions with the extrahepatic organs or tissues, for example, the gut, pancreas, adipose, skeletal muscle, heart, lung, kidney, brain, spleen, eyes, skin, bone, and sexual organs, through the circulation (including hemodynamics, redox signals, hepatokines, metabolites, and the translocation of microbiota or its products, such as endotoxins), the neural signals, or other forms of pathogenic factors, under normal or diseases status. The organ interactions centered on the liver not only influence the homeostasis of these indicated organs or tissues, but also contribute to the pathogenesis of cardiometabolic diseases (including obesity, type 2 diabetes mellitus, metabolic [dysfunction]-associated fatty liver diseases, and cardio-cerebrovascular diseases), pulmonary diseases, hyperuricemia and gout, chronic kidney disease, and male and female sexual dysfunction. Therefore, based on TCM and modern medicine, the liver has the bidirectional interaction with the extrahepatic organ or tissue, and this established bidirectional interaction system may further interact with another one or more extrahepatic organs/tissues, thus depicting a complex "pan-hepatic network" model. The pan-hepatic network acts as one of the essential mechanisms of homeostasis and the pathogenesis of diseases.

Pathophysiology of type 2 diabetes and the impact of altered metabolic interorgan crosstalk

Diabetes is a complex and multifactorial disease that affects millions of people worldwide, reducing the quality of life significantly, and results in grave consequences for our health care system. In type 2 diabetes (T2D), the lack of β-cell compensatory mechanisms overcoming peripherally developed insulin resistance is a paramount factor leading to disturbed blood glucose levels and lipid metabolism. Impaired β-cell functions and insulin resistance have been studied extensively resulting in a good understanding of these pathways but much less is known about interorgan crosstalk, which we define as signaling between tissues by secreted factors. Besides hormones and organokines, dysregulated blood glucose and long-lasting hyperglycemia in T2D is associated with changes in metabolism with metabolites from different tissues contributing to the development of this disease. Recent data suggest that metabolites, such as lipids including free fatty acids and amino acids, play important roles in the interorgan crosstalk during the development of T2D. In general, metabolic remodeling affects physiological homeostasis and impacts the development of T2D. Hence, we highlight the importance of metabolic interorgan crosstalk in this review to gain enhanced knowledge of the pathophysiology of T2D, which may lead to new therapeutic approaches to treat this disease.

Organokines, Sarcopenia, and Metabolic Repercussions: The Vicious Cycle and the Interplay with Exercise

Sarcopenia is a disease that becomes more prevalent as the population ages, since it is directly linked to the process of senility, which courses with muscle atrophy and loss of muscle strength. Over time, sarcopenia is linked to obesity, being known as sarcopenic obesity, and leads to other metabolic changes. At the molecular level, organokines act on different tissues and can improve or harm sarcopenia. It all depends on their production process, which is associated with factors such as physical exercise, the aging process, and metabolic diseases. Because of the seriousness of these repercussions, the aim of this literature review is to conduct a review on the relationship between organokines, sarcopenia, diabetes, and other metabolic repercussions, as well the role of physical exercise. To build this review, PubMed-Medline, Embase, and COCHRANE databases were searched, and only studies written in English were included. It was observed that myokines, adipokines, hepatokines, and osteokines had direct impacts on the pathophysiology of sarcopenia and its metabolic repercussions. Therefore, knowing how organokines act is very important to know their impacts on age, disease prevention, and how they can be related to the prevention of muscle loss.

Contribution of organokines in the development of NAFLD/NASH associated hepatocellular carcinoma

Globally the incidence of hepatocellular carcinoma (HCC) is on an upsurge. Evidence is accumulating that liver disorders like nonalcoholic fatty liver disease (NAFLD) and its more progressive form nonalcoholic steatohepatitis (NASH) are associated with increased risk of developing HCC. NAFLD has a prevalence of about 25% and 50%-90% in obese population. With the growing burden of obesity epidemic worldwide, HCC presents a major healthcare burden. While cirrhosis is one of the major risk factors of HCC, available literature suggests that NAFLD/NASH associated HCC also develops in minimum or noncirrhotic livers. Therefore, there is an urgent need to understand the pathogenesis and risk factors associated with NAFLD and NASH related HCC that would help in early diagnosis and favorable prognosis of HCC secondary to NAFLD. Adipokines, hepatokines and myokines are factors secreted by adipocytes, hepatocytes and myocytes, respectively, playing essential roles in cellular homeostasis, energy balance and metabolism with autocrine, paracrine and endocrine effects. In this review, we endeavor to focus on the role of these organokines in the pathogenesis of NAFLD/NASH and its progression to HCC to augment the understanding of the factors stimulating hepatocytes to acquire a malignant phenotype. This shall aid in the development of novel therapeutic strategies and tools for early diagnosis of NAFLD/NASH and HCC.

Non-Alcoholic Fatty Liver Disease and Metabolic Syndrome in Women: Effects of Lifestyle Modifications

Non-alcoholic fatty liver disease (NAFLD) is the most widespread liver disease, characterized by fatty acids liver accumulation and subsequent fibrosis. NAFLD prevalence ranges from 80% to 90% in obese subjects and is estimated to be around 50% in patients with metabolic syndrome. In this clinical scenario, diet and lifestyle modifications can play an important role. There are several imaging techniques that can accurately diagnose fatty liver. Recently, ultrasound has acquired a leading role in the diagnosis and follow-up of fatty liver disease. Furthermore, elastosonography represents a valid alternative to liver biopsy. Shear wave elastosonography evaluates the elastic and mechanical properties of liver tissue. The aim is to evaluate the effects of lifestyle and nutritional interventions and a loss of body weight during hepatic steatosis through ultrasonographic and elastosonographic techniques. Thirty-two female subjects with metabolic syndrome were subjected to clinical, anthropometric, and laboratory assessments, as well as abdominal ultrasonographic/elastosonographic measurements taken from enrollment time (T0) and after 3 months (T1) of lifestyle modifications. After 3 months of lifestyle changes, significant weight loss was observed, with a marked improvement in all adiposity indices. The laboratory parameters at T1 showed significant decreases in total and LDL cholesterol, triglycerides, basal blood glucose, 120 min glycaemia, basal insulin and HOMA Index (p < 0.001). A similar improvement was observed at T1 for steatosis degree (p < 0.01) and elastosonographic measurements (Kpa p < 0.001). The linear regression analysis of the baseline conditions documented that the size of the liver positively correlated with body weight, BMI, neck and waist circumferences, waist to height ratio (WhtR), insulin and HOMA Index, fat mass and visceral fat, and steatosis grade. After 3 months, the liver size showed improvement with positive correlations to all previous variables. Hepatic stiffness (Kpa) positively correlated with neck circumference, visceral fat, and ALT, with basal insulin, gamma-GT, and AST, and with waist circumference, WhtR, and fat mass. The degree of steatosis was positively correlated with more variables and with greater statistical significance at T1 with respect to T0. Particularly, the positive correlations between the degree of steatosis and neck circumference (p < 0.001), HOMA Index, and triglycerides (p < 0.001) appeared to be very significant. NAFLD management in women with metabolic syndrome should be focused on lifestyle modifications. Moreover, liver involvement and improvement at follow-up could be evaluated in a non-invasive manner through ultrasonographic and elastosonographic techniques.

Hepatic PTEN Signaling Regulates Systemic Metabolic Homeostasis through Hepatokines-Mediated Liver-to-Peripheral Organs Crosstalk

Liver-derived circulating factors deeply affect the metabolism of distal organs. Herein, we took advantage of the hepatocyte-specific PTEN knockout mice (LPTENKO), a model of hepatic steatosis associated with increased muscle insulin sensitivity and decreased adiposity, to identify potential secreted hepatic factors improving metabolic homeostasis. Our results indicated that protein factors, rather than specific metabolites, released by PTEN-deficient hepatocytes trigger an improved muscle insulin sensitivity and a decreased adiposity in LPTENKO. In this regard, a proteomic analysis of conditioned media from PTEN-deficient primary hepatocytes identified seven hepatokines whose expression/secretion was deregulated. Distinct expression patterns of these hepatokines were observed in hepatic tissues from human/mouse with NAFLD. The expression of specific factors was regulated by the PTEN/PI3K, PPAR or AMPK signaling pathways and/or modulated by classical antidiabetic drugs. Finally, loss-of-function studies identified FGF21 and the triad AHSG, ANGPTL4 and LECT2 as key regulators of insulin sensitivity in muscle cells and in adipocytes biogenesis, respectively. These data indicate that hepatic PTEN deficiency and steatosis alter the expression/secretion of hepatokines regulating insulin sensitivity in muscles and the lipid metabolism in adipose tissue. These hepatokines could represent potential therapeutic targets to treat obesity and insulin resistance.

Higher serum level of CTRP15 in patients with coronary artery disease is associated with disease severity, body mass index and insulin resistance

BACKGROUND

CTRP15 is a prologue of adiponectin which has shown to have favourable effects on glucose and lipid metabolism. Studies have reported lower levels of CTRP15 in T2DM and metabolic syndrome; however, its circulating levels have not been evaluated in CAD patients.

METHODS

This case-control study was conducted on 190 angiographically confirmed coronary artery disease (CAD) patients and 70 controls. Serum levels of CTRP15, adiponectin, TNF-α, and IL-6 were measured using the ELISA technique.

RESULTS

CTRP15 was shown to occur in higher levels in CAD patients compared with controls. In CAD patients, CTRP15 showed a positive correlation with BMI, FBS, insulin, HOMA-IR, IL-6, and TNF-α and a negative correlation with HDL-C and adiponectin.

CONCLUSION

Elevated levels of CTRP15 in CAD patients and the relation of CTRP15 with pathogenic conditions such as insulin resistance, inflammation, and decreased adiponectin and HDL-C suggest a possible compensatory response to these conditions in CAD patients.

Non-Alcoholic Steatohepatitis (NASH) and Organokines: What Is Now and What Will Be in the Future

Non-alcoholic steatohepatitis (NASH) is characterized by steatosis, lobular inflammation, and enlargement of the diameter of hepatocytes (ballooning hepatocytes), with or without fibrosis. It affects 20% of patients with non-alcoholic fatty liver disease (NAFLD). Due to liver dysfunction and the numerous metabolic changes that commonly accompany the condition (obesity, insulin resistance, type 2 diabetes, and metabolic syndrome), the secretion of organokines is modified, which may contribute to the pathogenesis or progression of the disease. In this sense, this study aimed to perform a review of the role of organokines in NASH. Thus, by combining descriptors such as NASH, organokines, oxidative stress, inflammation, insulin resistance, and dyslipidemia, a search was carried out in the EMBASE, MEDLINE-PubMed, and Cochrane databases of articles published in the last ten years. Insulin resistance, inflammation and mitochondrial dysfunction, fructose, and intestinal microbiota were factors identified as participating in the genesis and progression of NASH. Changes in the pattern of organokines secretion (adipokines, myokines, hepatokines, and osteokines) directly or indirectly contribute to aggravating the condition or compromise homeostasis. Thus, further studies involving skeletal muscle, adipose, bone, and liver tissue as endocrine organs are essential to better understand the modulation of organokines involved in the pathogenesis of NASH to advance in the treatment of this disease.

Hepatokines and Non-Alcoholic Fatty Liver Disease: Linking Liver Pathophysiology to Metabolism

The liver plays a key role in maintaining energy homeostasis by sensing and responding to changes in nutrient status under various metabolic conditions. Recently highlighted as a major endocrine organ, the contribution of the liver to systemic glucose and lipid metabolism is primarily attributed to signaling crosstalk between multiple organs via hepatic hormones, cytokines, and hepatokines. Hepatokines are hormone-like proteins secreted by hepatocytes, and a number of these have been associated with extra-hepatic metabolic regulation. Mounting evidence has revealed that the secretory profiles of hepatokines are significantly altered in non-alcoholic fatty liver disease (NAFLD), the most common hepatic manifestation, which frequently precedes other metabolic disorders, including insulin resistance and type 2 diabetes. Therefore, deciphering the mechanism of hepatokine-mediated inter-organ communication is essential for understanding the complex metabolic network between tissues, as well as for the identification of novel diagnostic and/or therapeutic targets in metabolic disease. In this review, we describe the hepatokine-driven inter-organ crosstalk in the context of liver pathophysiology, with a particular focus on NAFLD progression. Moreover, we summarize key hepatokines and their molecular mechanisms of metabolic control in non-hepatic tissues, discussing their potential as novel biomarkers and therapeutic targets in the treatment of metabolic diseases.

Inter-Organ Crosstalk in the Development of Obesity-Associated Insulin Resistance

The epidemics of obesity and type 2 diabetes have led to intensive investigation of the underlying mechanisms of these diseases and their main complications such as cardiovascular diseases and non-alcoholic fatty liver disease. This search has contributed to better understand how organs and tissues communicate with each other in the so-called inter-organ crosstalk. Adipose tissue, the liver, or skeletal muscle can actively release secreted factors termed "organokines" which can interact with other distant targets in complex networks. More recently, other novel mediators of inter-organ crosstalk such as extracellular vesicles and their non-traditional cargoes as miRNAs and lncRNAs are gaining importance and represent potential therapeutic targets. In the present chapter we summarize some of the current knowledge on inter-organ communication with a focus on adipose tissue-released factors and their modulation on other organs and tissues like pancreas, liver, skeletal muscle, the cardiovascular system, and the gut in the context of obesity and its progression to insulin resistance. We also provide a perspective on mediators of inter-organ crosstalk as potential therapeutic targets.

Pilates and TRX training methods can improve insulin resistance in overweight women by increasing an exercise-hormone, Irisin

AIMS AND BACKGROUND

Physical inactivity is leading to obesity and consequently insulin resistance and diabetes. Feasible and cost efficient strategies like Pilates and total body resistance exercise (TRX) training can impede obesity and its compilation. The aim of this study was to investigate the effects of 8 weeks Pilates and TRX training programs on irisin concentration and insulin resistance in overweight women.

METHOD

Thirty overweight women (Body mass index (BMI): 25-29.9 kg/m2) were divided, based on their BMI, into 3 groups; control, Pilates and TRX. The participants in the training groups were subjected to moderate intensity of Pilates or TRX exercise training 3 times a week for 8 weeks. Blood samples were taken at pre-test and 48 h after the last training session and used for analyzing irisin, insulin and glucose. Data were analyzed by ANCOVA and paired-samples t-test.

RESULTS

The finding showed that the Pilates training decreased body weight and BMI compared to the pre-test (P < 0.05). Also, it has been revealed that irisin concentration in response to Pilates and TRX training programs were increased in comparison with the control group (P < 0.05). However, there was no significant difference in irisin concentrations between training groups (p > 0.05). Moreover, fasting insulin, glucose and insulin resistance were significantly reduced after exercise intervention compared to the pre-test which were significantly lowered compared to the control group as well.

CONCLUSION

The results suggest Pilates and TRX trainings are two efficient model of exercise that by eliciting an exercise-hormone, irisin, can improve insulin resistance in overweight women.

Effects of GLP-1 receptor agonists on myokine levels and pro-inflammatory cytokines in patients with type 2 diabetes mellitus

BACKGROUND AND AIMS

To evaluate the change in circulating serum irisin and interleukin-6 (IL-6), in patients with type 2 diabetes mellitus (T2DM) after 6 and 12 months of GLP-1 treatment.

METHODS AND RESULTS

Eighty-five patients with T2DM inadequately controlled with insulin or other hypoglycaemic drugs were added to dulaglutide (N° = 44) and liraglutide (N° = 41) treatment. After 6 months of GLP-1 analogues a significant decrease in BMI (p < 0.001), waist circumference (WC) (p < 0.001), fasting blood glucose (p < 0.001), HbA1c (p < 0.001), total cholesterol (p < 0.001), LDL-cholesterol (p = 0.003), triglycerides (p = 0.017), IL-6 (p = 0.045) and a significant increase in serum irisin (p < 0.001) were observed compared to baseline. After 12 months of treatment no significant differences were found compared to the levels at 6 months. The change in irisin from baseline (Δ_irisin) was significantly related to the changes in total-cholesterol (Δ_total-cholesterol) (r = -0.293; p = 0.020), while the change in IL-6 (Δ_IL-6) was significantly related to the changes in WC (Δ_WC) (r = 0.347; p = 0.006).

CONCLUSIONS

Additive treatment with GLP1-analogues results in an increase in serum circulating irisin levels and a decrease in IL-6. The post-treatment change in irisin was correlated with a decrease in total cholesterol, while the change in IL-6 was correlated with a decrease in WC.

Irisin in atherosclerosis

Irisin, a novel exercise-induced myokine, has been shown to play important roles in increasing white adipose tissue browning, regulating energy metabolism and improving insulin resistance. Growing evidence suggests a direct role for irisin in preventing atherosclerosis (AS) by inhibiting oxidative stress, improving dyslipidemia, facilitating anti-inflammation, reducing cellular damage and recovering endothelial function. In addition, some studies have noted that serum irisin levels play an essential role in cardiovascular diseases (CVDs) risk prediction, highlighting that irisin has the potential to be a useful predictive marker and therapeutic target of AS, especially in monitoring therapeutic efficacy. This review summarizes the understanding of irisin-mediated regulation in essential biological pathways and functions in atherosclerosis and prompts further exploitation of the biological properties of irisin in the pathogenesis of atherosclerosis.

Crossing the Antarctica: Exploring the Effects of Appetite-Regulating Hormones and Indicators of Nutrition Status during a 93-Day Solo-Expedition

Future deep space astronauts must maintain adequate nutrition despite highly stressful, isolated, confined and dangerous environments. The present case-study investigated appetite regulating hormones, nutrition status, and physical and emotional stress in a space analog condition: an explorer conducting a 93-day unsupported solo crossing of Antarctica. Using the dried blood spot (DBS) method, the subject drew samples of his blood on a regular basis during the expedition. The DBSs were later analyzed for the appetite regulating hormones leptin and adiponectin. Energy intake and nutritional status were monitored by analysis of albumin and globulin (including their ratio). Interleukin-6 (IL-6) was also analyzed and used as an energy sensor. The results showed a marked reduction in levels of the appetite-reducing hormone, leptin, and the appetite stimulating hormone, adiponectin, during both extreme physical and psychological strain. Nutrition status showed a variation over the expedition, with below-normal levels during extreme psychological strain and levels abutting the lower bounds of the normal range during a phase dominated by extreme physical hardship. The IL-6 levels varied substantially, with levels above the normal range except during the recovery phase. It was concluded that a daily intake of 5058 to 5931 calories seemed to allow recovery of both appetite and nutritional status between extreme physical and psychological hardship during a long Arctic expedition. Furthermore, IL-6 may be a sensor in the muscle-liver, muscle-fat and muscle-brain crosstalk. These results may help guide nutrition planning for future astronaut crews, mountaineers and others involved in highly demanding missions.

Handgrip and sex-specific cardiometabolic risk factors in Hispanic/Latino migrant farmworkers

Studies have suggested that handgrip strength might be a marker for cardiometabolic risk (CMR), but it has not been studied in Hispanic/Latino farmworker population. This study aimed to characterize absolute and relative handgrip strength in Hispanic/Latino farmworkers, and investigate the sex-specific association between handgrip strength and CMR factors. CMR factors and seated isometric absolute (the sum of both hands) and relative (absolute handgrip strength divided by body mass index) handgrip strengths were collected in 173 Hispanic/Latino farmworkers (mean age 35.1 ± 0.7 years; 49% female). The absolute and the relative handgrip strengths were 89.2 ± 1.8 kg, 3.3 ± 0.1 kg among males, and 56.5 ± 1.9 kg, 1.9 ± 0.1 kg among females, respectively. Age was correlated with absolute (r = - 0.17, p = 0.03) and relative handgrip strengths (r = - 0.28, p < 0.01). In males, absolute handgrip was related to triglycerides (r = - 0.25, p < 0.05), whereas relative handgrip was related to waist circumference (r = - 0.32, p < 0.01), waist/hip circumference ratio (r = - 0.36, p < 0.01), high-density lipoprotein (r = 0.24, p < 0.05), and triglycerides (r = - 0.35, p < 0.01). In females, absolute handgrip was related to fasting plasma glucose (r = - 0.28, p = 0.03), whereas relative handgrip was related to waist circumference (r = - 0.38, p < 0.01) and fasting plasma glucose (r = - 0.22, p < 0.05). Males had lower absolute handgrip strength when their triglycerides levels were at risk (p = 0.021), and lower relative handgrip strength when their plasma glucose (p = 0.034) and triglycerides (p = 0.002) levels were at risk. Females had lower relative handgrip strength when their plasma glucose (p = 0.001) and blood pressure (p = 0.004) were at risk. This study suggests that handgrip strength may be associated with sex-specific CMR factors in a Hispanic/Latino farmworker population.

The Effects of Two Different Intensities of Combined Training on C1q/TNF-Related Protein 3 (CTRP3) and Insulin Resistance in Women with Non-alcoholic Fatty Liver Disease

Background: C1q/TNF-related protein (CTRP3) is a potent anti-inflammatory adipokine with activities, such as reduction of glucose level and inhibition of gluconeogenesis in the liver. However, the effect of exercise training on CTRP3 in patients with non-alcoholic fatty liver disease (NAFLD) remains unknown. Objectives: This study was done to investigate the effects of two different intensities of combined training on CTRP3 and insulin resistance in women with NAFLD and compare these two training patterns. Methods: Thirty-three women with NAFLD were randomly divided into three equal groups. Group 1 performed resistance training (RT), along with aerobic interval training (AIT) (2 - 5 intervals of four minutes, 70 - 75% HRmax), group 2 performed RT along with high-intensity interval training (HIIT) (8 - 13 intervals of one minute, 85 - 95% HRmax), and the control group did not participate in any training. The body composition measurements and blood sampling were carried out before and after 12 weeks of training. Data analysis was performed using repeated-measures ANOVA (α ≤ 0.05). Results: After 12 weeks, the CTRP3 level significantly increased in group 1 compared with the control group (P = 0.01) and group 2 (P < 0.001). The fasting glucose and fasting insulin levels significantly decreased in group 1 compared with the control group (P < 0.001 and P = 0.01, respectively). The insulin resistance index decreased in both group 1 and group 2; however, the difference was not significant compared with the control group (P > 0.05). Conclusions: Combined training (RT + AIT) in the present study increased the level of CTRP3; thus, it is likely that women with NAFLD can benefit from this program as a non-pharmacological adjunct treatment to prevent inflammation and progression of the disease.

Adipokines, Myokines, and Hepatokines: Crosstalk and Metabolic Repercussions

Adipose, skeletal, and hepatic muscle tissues are the main endocrine organs that produce adipokines, myokines, and hepatokines. These biomarkers can be harmful or beneficial to an organism and still perform crosstalk, acting through the endocrine, paracrine, and autocrine pathways. This study aims to review the crosstalk between adipokines, myokines, and hepatokines. Far beyond understanding the actions of each biomarker alone, it is important to underline that these cytokines act together in the body, resulting in a complex network of actions in different tissues, which may have beneficial or non-beneficial effects on the genesis of various physiological disorders and their respective outcomes, such as type 2 diabetes mellitus (DM2), obesity, metabolic syndrome, and cardiovascular diseases (CVD). Overweight individuals secrete more pro-inflammatory adipokines than those of a healthy weight, leading to an impaired immune response and greater susceptibility to inflammatory and infectious diseases. Myostatin is elevated in pro-inflammatory environments, sharing space with pro-inflammatory organokines, such as tumor necrosis factor-alpha (TNF-α), interleukin-1 (IL-1), resistin, and chemerin. Fibroblast growth factor FGF21 acts as a beta-oxidation regulator and decreases lipogenesis in the liver. The crosstalk mentioned above can interfere with homeostatic disorders and can play a role as a potential therapeutic target that can assist in the methods of diagnosing metabolic syndrome and CVD.

Inflammatory biomarkers and prediction of insulin resistance in Congolese adults

Several studies have shown that low levels of adiponectin (ADP) and high levels of alpha tumor necrosis factor (NFT) increase the risk or severity of many cardiometabolic diseases associated with insulin resistance. The main objective of this study was to evaluate the association between plasma adipokines and IR measured by HOMA-IR. The secondary objective was to determine the biomarker of the potential inflammation to predict IR in Congolese melanoderm subjects residing in Brazzaville. This cross-sectional study was conducted on 234 apparently healthy participants over the age of 18. Socio-demographic and clinical data were collected. Biological data, including the total ADP and NFT dosage, were measured using the ELISA method. Participants were categorized into two groups according to HOMA-IR ≥ 2.5. Univariate and multivariate logistic regression analyses were conducted to identify risk factors for insulin resistance. An optimized model was obtained after the logistic regression. The analysis of the receptor's operating characteristics (OCR) was performed to determine the optimal threshold value and diagnostic characteristics, as well as the area under the curve (ASC). ADP averages were significantly low (11.49 ± 7.61 ng/mL; P < 0.001) while those of TNF were significantly higher (96.03 ± 44.09 pg/mL) in the HOMA-IR group ≥ 2.5. There was a positive and significant correlation (p < 0.05) between BMI, TT, CRPhs, TNF and HOMA-IR. And a negative and significant correlation was noted between ADP and HOMA-IR (r = - 0.39; P < 0.01). Similarly, a negative and significant correlation (p < 0.01) was noted between BMI, TT, TNF, CRPhs and ADP. The optimal threshold value of the total ADP for predicting IR was 17.52 ng/mL with a sensitivity of 89% [IC 95% (0.83-0.95)], 56% specificity [IC 95% (0.47-0.65)] and a CSA of 0.76 [IC 95% (0.69-0.81)]. After logistic regression, the CSA of the optimized model was 0.84 [IC 95% (0.79-0.89)]. ADP can be used as a highly plausible IR prediction biomarker.

Fetuin-A as a Potential Biomarker of Metabolic Variability Following 60 Days of Bed Rest

Background: Fetuin-A is a hepatokine linked to the development of insulin resistance. The purpose of this study was to determine if 60 days head-down-tilt (HDT) bed rest increased circulating fetuin-A and if it was linked to whole body insulin sensitivity (IS). Additionally, we examined whether reactive jump training (RJT) could alleviate the metabolic changes associated with bed rest. Methods: 23 young men (29 ± 6 years, 181 ± 6 cm, 77 ± 7 kg) were randomized to a control (CTRL, n = 11) or RJT group (JUMP, n = 12) and exposed to 60 days of bed rest. Before and after bed rest, body composition and V . O 2 ⁢ p ⁢ e ⁢ a ⁢ k were measured and an oral glucose tolerance test was performed to estimate IS. Circulating lipids and fetuin-A were measured in fasting serum. Results: Body weight, lean mass, and V . O 2 ⁢ p ⁢ e ⁢ a ⁢ k decreased in both groups following bed rest, with greater reductions in CTRL (p < 0.05). There was a main effect of time, but not the RJT intervention, for the increase in fetuin-A, triglycerides (TG), area under the curve for glucose (AUCG) and insulin (AUCI), and the decrease in Matsuda and tissue-specific IS (p < 0.05). Fetuin-A increased in participants who became less insulin sensitive (p = 0.019). In this subgroup, liver IS and adipose IS decreased (p < 0.05), while muscle IS was unchanged. In a subgroup, where IS did not decrease, fetuin-A did not change. Liver IS increased (p = 0.012), while muscle and adipose tissue IS remained unchanged. Conclusions: In this study, we report an increase in circulating fetuin-A following 60 days of bed rest, concomitant with reduced IS, which could not be mitigated by RJT. The amount of fetuin-A released from the liver may be an important determinant of changes in whole body IS. In this regard, it may also be a useful biomarker of individual variation due to inactivity or lifestyle interventions.

Dysregulated Autophagy Mediates Sarcopenic Obesity and Its Complications via AMPK and PGC1α Signaling Pathways: Potential Involvement of Gut Dysbiosis as a Pathological Link

Sarcopenic obesity (SOB), which is closely related to being elderly as a feature of aging, is recently gaining attention because it is associated with many other age-related diseases that present as altered intercellular communication, dysregulated nutrient sensing, and mitochondrial dysfunction. Along with insulin resistance and inflammation as the core pathogenesis of SOB, autophagy has recently gained attention as a significant mechanism of muscle aging in SOB. Known as important cellular metabolic regulators, the AMP-activated protein kinase (AMPK) and the peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1α) signaling pathways play an important role in autophagy, inflammation, and insulin resistance, as well as mutual communication between skeletal muscle, adipose tissue, and the liver. Furthermore, AMPK and PGC-1α signaling pathways are implicated in the gut microbiome-muscle axis. In this review, we describe the pathological link between SOB and its associated complications such as metabolic, cardiovascular, and liver disease, falls and fractures, osteoarthritis, pulmonary disease, and mental health via dysregulated autophagy controlled by AMPK and/or PGC-1α signaling pathways. Here, we propose potential treatments for SOB by modulating autophagy activity and gut dysbiosis based on plausible pathological links.

Nonalcoholic fatty liver disease and cardiovascular disease phenotypes

Nonalcoholic fatty liver disease is increasingly recognized as a major global health problem. Intertwined with diabetes, metabolic syndrome, and obesity, nonalcoholic fatty liver disease embraces a spectrum of liver conditions spanning from steatosis to inflammation, fibrosis, and liver failure. Compared with the general population, the prevalence of cardiovascular disease is higher among nonalcoholic fatty liver disease patients, in whom comprehensive cardiovascular risk assessment is highly desirable. Preclinical effects of nonalcoholic fatty liver disease on the heart include both metabolic and structural changes eventually preceding overt myocardial dysfunction. Particularly, nonalcoholic fatty liver disease is associated with enhanced atherosclerosis, heart muscle disease, valvular heart disease, and arrhythmias, with endothelial dysfunction, inflammation, metabolic dysregulation, and oxidative stress playing in the background. In this topical review, we aimed to summarize current evidence on the epidemiology of nonalcoholic fatty liver disease, discuss the pathophysiological links between nonalcoholic fatty liver disease and cardiovascular disease, illustrate nonalcoholic fatty liver disease-related cardiovascular phenotypes, and finally provide a glimpse on the relationship between nonalcoholic fatty liver disease and cardiac steatosis, mitochondrial (dys)function, and cardiovascular autonomic dysfunction.

Higher circulating levels of ANGPTL8 are associated with body mass index, triglycerides, and endothelial dysfunction in patients with coronary artery disease

Bac Coronary artery disease (CAD) is the leading cause of death worldwide and most commonly develops as a result of atherosclerosis. ANGPTL8 is a secreted adipokine that regulates lipid metabolism and is associated with cardiometabolic diseases, including type 2 diabetes and CAD. However, the association between circulating ANGPTL8 levels and CAD is inconsistent among studies and the mechanism by which ANGPTL8 contributes to CAD development remains poorly understood. Here we sought to evaluate the relationship between ANGPTL8 levels and endothelial dysfunction and adipose tissue inflammation in CAD patients. Concentrations of ANGPTL8, adiponectin, TNF-α, IL6, hsCRP, ICAM-1, and VCAM-1 were measured by ELISA in serum samples from 192 CAD patients diagnosed with stenosis > 50% in at least one coronary artery by angiography and 71 individuals with normal heart function. Serum ANGPTL8 levels were significantly higher in CAD patients compared to controls (83.84 ± 23.25 ng/mL vs. 50.45 ± 17.73; p < 0.001), independent of adjustment for age, sex, BMI, smoking and statin use. ANGPTL8 could also differentiate CAD patients from controls with 82.3% specificity and 81.4% sensitivity (p < 0.001). Adiponectin levels were lower in CAD patients, while ICAM-1, VCAM-1, TNF-α, IL6, and hsCRP levels were higher compared to non-CAD controls (all p < 0.001). ANGPTL8 levels were associated with BMI in controls and with BMI, TG, and ICAM-1 in CAD patients. The presence of elevated ANGPTL8 levels in CAD patients and independent association with TG and ICAM-1 suggest a possible role related to endothelial dysfunction in the pathogenesis of atherosclerosis.

The Role of Adipose Tissue and Adipokines in Sepsis: Inflammatory and Metabolic Considerations, and the Obesity Paradox

PURPOSE

Sepsis has become a global health problem with rising incidence and high mortality, creating a substantial social and economic burden. Early diagnosis and treatment can improve outcome, but reliable sepsis biomarkers are lacking. This review summarizes current evidence of the pathophysiological mechanisms linking adipose tissue to sepsis and presents experimental and clinical data on adipokines and sepsis along with important insights into the obesity paradox in sepsis survival.

RECENT FINDINGS

Sepsis is characterized by significant alterations in circulating cytokines and adipokines, biologically active molecules produced by the adipose tissue, being implicated in metabolic and inflammatory processes. Although data are inconclusive regarding classic adipokines such as leptin and adiponectin, recent evidence have highlighted the striking elevation of resistin and visfatin in critical illness and sepsis as well as their association with sepsis severity and outcomes. Given that inflammatory and metabolic pathways are involved in sepsis, studying adipokines presents an attractive, innovative, and promising research field that may provide more powerful diagnostic and prognostic biomarkers as well as novel therapeutic targets, empowering the therapeutic armamentarium for sepsis management in order to improve survival.

Pathophysiological Implication of Fetuin-A Glycoprotein in the Development of Metabolic Disorders: A Concise Review

Alpha 2-Heremans-Schmid glycoprotein, also known as fetuin-A (Fet-A), is a multifunctional plasma glycoprotein that has been identified in both animal and human beings. The protein is a hepatokine predominantly synthesized in the liver, which is considered as an important component of diverse normal and pathological processes, including bone metabolism regulation, vascular calcification, insulin resistance, and protease activity control. Epidemiological studies have already consistently demonstrated significant elevated circulating Fet-A in the course of obesity and related complications, such as type 2 diabetes mellitus, metabolic syndrome, and nonalcoholic fatty liver disorder (NAFLD). Moreover, Fet-A has been strongly correlated with many parameters related to metabolic homeostasis dysregulation, such as insulin sensitivity, glucose tolerance, circulating lipid levels (non-esterified free fatty acids and triglycerides), and circulating levels of both pro- and anti-inflammatory factors (C-reactive protein, tumor necrosis factor-α (TNF-α), and interleukin (IL)-6). Metabolic-interfering effects of Fet-A have thus been shown to highly exacerbate insulin resistance (IR) through blocking insulin-stimulated glucose transporter 4 (GLUT-4) translocation and protein kinase B (Akt) activation. Furthermore, the protein appeared to interfere with downstream phosphorylation events in insulin receptor and insulin receptor substrate signaling. The emerging importance of Fet-A for both diagnosis and therapeutics has therefore come to the attention of researchers and the pharmaceutical industry, in the prospect of developing new therapeutic strategies and diagnosis methods for metabolic disorders.

Sarcopenia and myokines profile as risk factors in cardiovascular diseases?

Skeletal muscles and substances released during physical activity (myokines) have a beneficial influence on the functioning of the organism. Myokines (released also by myocardium) together with hepatokines and adipokines play an important role not only in energetic metabolism, but they also influence, among others, the function of the circulatory and nervous systems, modulation of inflammatory state and atherogenesis. Under pathological conditions connected with the presence of chronic diseases, chronic inflammatory state, low physical activity, long-term immobility the following consequences are observed: reduction of muscle mass and strength (sarcopenia) and changed profile of released myokines. The incidence of sarcopenia is connected with an unfavorable course of the aging process, often leading to disability and multiple morbidities. Sarcopenia can also lead to frailty syndrome, which not only worsens the prognosis of various diseases, but it can also increase the risk of medical procedures. Sarcopenia and adverse przymyokine profile are modifiable risk factors of cardiovascular diseases and affecting them may improve functional status and prognosis. An important intervention to improve muscles function and myokine profile, apart from nutritional treatment and pharmacotherapy, is regular physical activity as a component of cardiac rehabilitation. In our paper we focused on a review of the newest research regarding the association of sarcopenia and the profile of released myokines with incidence and course of cardiovascular diseases such as chronic heart failure, coronary artery disease, carotid artery atherosclerosis or ischemic cerebral stroke.

Loss of Glycine N-Methyltransferase Associates with Angiopoietin-Like Protein 8 Expression in High Fat-Diet-Fed Mice

Imbalance of lipid metabolism is a main cause of metabolic syndrome leading to life-threatening metabolic diseases. Angiopoietin-like protein 8 (Angptl8) was recently identified as a liver and adipose tissue-released hormone that is one of the molecules involved in triglyceride metabolism. However, the regulatory mechanism of Angptl8 is largely unknown. A high fat diet (HFD)-fed mouse model, which showed high cholesterol, high triglyceride, and high insulin in the blood, revealed the upregulation of hepatic and plasma Angptl8 and the downregulation of hepatic glycine N-methyltransferase (GNMT). The inverse correlation of hepatic Angptl8 and GNMT expression in the livers of HFD-fed mice was also confirmed in a publicly available microarray dataset. The mechanistic study using primary hepatocytes showed that the Angptl8 expression could be induced by insulin treatment in a dose- and time-dependent manner. Inhibition of PI3K/Akt pathway by the specific inhibitors or the dominant-negative Akt blocked the insulin-induced Angptl8 expression. Moreover, knockout of GNMT promoted the Akt activation as well as the Angptl8 expression. These results suggested that GNMT might be involved in insulin-induced Angptl8 expression in HFD-mediated metabolic syndrome.

Organokines in disease

Studies have linked obesity, metabolic syndrome, type 2 diabetes, cardiovascular disease (CVD), nonalcoholic fatty liver disease (NAFLD) and dementia. Their relationship to the incidence and progression of these disease states suggests an interconnected pathogenesis involving chronic low-grade inflammation and oxidative stress. Metabolic syndrome represents comorbidities of central obesity, insulin resistance, dyslipidemia, hypertension and hyperglycemia associated with increased risk of type 2 diabetes, NAFLD, atherosclerotic CVD and neurodegenerative disease. As the socioeconomic burden for these diseases has grown signficantly with an increasing elderly population, new and alternative pharmacologic solutions for these cardiometabolic diseases are required. Adipose tissue, skeletal muscle and liver are central endocrine organs that regulate inflammation, energy and metabolic homeostasis, and the neuroendocrine axis through synthesis and secretion of adipokines, myokines, and hepatokines, respectively. These organokines affect each other and communicate through various endocrine, paracrine and autocrine pathways. The ultimate goal of this review is to provide a comprehensive understanding of organ crosstalk. This will include the roles of novel organokines in normal physiologic regulation and their pathophysiological effect in obesity, metabolic syndrome, type 2 diabetes, CVD, NAFLD and neurodegenerative disorders.

The implication of hepatokines in metabolic syndrome

Hepatokines are liver-derived proteins with equivocal roles in metabolic syndrome (MetS). These proteins have prominent role in pathogenesis of MetS component such as obesity, insulin resistance, dyslipidemia and hypertension. The identification and functional characterization of hepatokines may provide significant insights that could help in better understanding of MetS pathogenesis. Fetuin-A, Hepatocyte-derived fibrinogen-related protein 1, Fibroblast growth factor 21, Angiopoietin-related growth factor, Selenoprotein-P, Angiopoietin like proteins, Leukocyte cell-derived chemotaxin 2 are regarded as the most significant hepatokines. We describe recent data on these new hormones in progression of MetS. Understanding of the accurate role of these proteins in pathophysiology of MetS can help improving prevention and treatment of this syndrome.

Insulin-stimulated glucose uptake in skeletal muscle, adipose tissue and liver: a positron emission tomography study

OBJECTIVE

Insulin resistance is reflected by the rates of reduced glucose uptake (GU) into the key insulin-sensitive tissues, skeletal muscle, liver and adipose tissue. It is unclear whether insulin resistance occurs simultaneously in all these tissues or whether insulin resistance is tissue specific.

DESIGN AND METHODS

We measured GU in skeletal muscle, adipose tissue and liver and endogenous glucose production (EGP), in a single session using ¹⁸F-fluorodeoxyglucose with positron emission tomography (PET) and euglycemic-hyperinsulinemic clamp. The study population consisted of 326 subjects without diabetes from the CMgene study cohort.

RESULTS

Skeletal muscle GU less than 33 µmol/kg tissue/min and subcutaneous adipose tissue GU less than 11.5 µmol/kg tissue/min characterized insulin-resistant individuals. Men had considerably worse insulin suppression of EGP compared to women. By using principal component analysis (PCA), BMI inversely and skeletal muscle, adipose tissue and liver GU positively loaded on same principal component explaining one-third of the variation in these measures. The results were largely similar when liver GU was replaced by EGP in PCA. Liver GU and EGP were positively associated with aging.

CONCLUSIONS

We have provided threshold values, which can be used to identify tissue-specific insulin resistance. In addition, we found that insulin resistance measured by GU was only partially similar across all insulin-sensitive tissues studied, skeletal muscle, adipose tissue and liver and was affected by obesity, aging and gender.

Effects of chlorogenic acid on intracellular calcium regulation in lysophosphatidylcholine-treated endothelial cells

Lysophosphatidylcholine (LPC) is a major phospholipid component of oxidized low-density lipoprotein (ox-LDL) and is implicated in its atherogenic activity. This study investigated the effects of LPC on cell viability, intracellular calcium homeostasis, and the protective mechanisms of chlorogenic acid (CGA) in human umbilical vein endothelial cells (HUVECs). LPC increased intracellular calcium ([Ca²⁺]_i) by releasing Ca²⁺ from intracellular stores and via Ca²⁺ influx through store-operated channels (SOCs). LPC also increased the generation of reactive oxygen species (ROS) and decreased cell viability. The mRNA expression of Transient receptor potential canonical (TRPC) channel 1 was increased significantly by LPC treatment and suppressed by CGA. CGA inhibited LPC-induced Ca²⁺ influx and ROS generation, and restored cell viability. These results suggested that CGA inhibits SOC-mediated Ca²⁺ influx and ROS generation by attenuating TRPC1 expression in LPC-treated HUVECs. Therefore, CGA might protect endothelial cells against LPC injury, thereby inhibiting atherosclerosis.

Serum Vaspin Concentration in Elderly Type 2 Diabetes Mellitus Patients with Differing Body Mass Index: A Cross-Sectional Study

Aims. This study was to evaluate the association of serum vaspin concentrations with body mass index (BMI) among elderly patients (>60 years old). Methods. A total of 227 elderly individuals included 76 healthy with normal glucose tolerance, which divided into normal weight control (BMI < 25, n = 38) and overweight or obese control (BMI ≥ 25, n = 38) subgroups, and 150 T2DM patients, which divided into normal weight diabetes (BMI < 25, n = 55), overweight diabetes (30 > BMI ≥ 25, n = 52), and obese diabetes (BMI ≥ 30, n = 43) subgroups. Relevant parameters were matched for age and gender ratio. Serum vaspin concentrations were measured by enzyme-linked immunosorbent assay. Results. Serum vaspin concentration was significantly higher in the T2DM than the healthy (451.9 ± 32.6 versus 284.2 ± 21.7, P < 0.01). In the diabetic patients, the vaspin concentration was significantly higher in the obese group than the normal weight group (498.2 ± 17.1 versus 382.1 ± 21.3, P < 0.05). In addition, the concentration of vaspin in normal weight T2DM was higher than in healthy control group with normal weight (382.1 ± 21.3 versus 192.5 ± 45.2, P < 0.05). Multiple regression analysis revealed that BMI was independent factors influencing the serum vaspin concentration in all participants. Conclusion. Vaspin may play an important compensatory role in obesity and insulin resistance in elderly people. The clinical trial registration number is ChiCTR-OPC-14005698.

Low muscle mass and risk of type 2 diabetes in middle-aged and older adults: findings from the KoGES

AIMS/HYPOTHESIS

Asians have a propensity to develop type 2 diabetes with a lower BMI than Western populations. This discrepancy may be due to differences in body fat and muscle mass for a given BMI. However, unlike adiposity, it is unclear whether muscle mass affects the risk of type 2 diabetes in Asian populations.

METHODS

We conducted a 2-yearly prospective assessment of 6895 participants who were free of diabetes at the baseline examination as part of the Korean Genome Epidemiology Study. The muscle mass index (MMI) was defined as the weight-adjusted appendicular skeletal muscle mass. Using Cox regression models, we evaluated the association between MMI and the risk of developing type 2 diabetes across sex-specific tertiles of MMI. Low muscle mass was defined as the sex-specific lowest tertile of MMI. Main covariates included age, sex, urban or rural residence, family history of diabetes, hypertension, smoking status, education level, monthly income, physical activity, alcohol consumption and diet. In addition, body fat mass, waist circumference and BMI were controlled as categorical variables. Obesity was defined as a BMI of ≥25 kg/m² or a waist circumference of ≥90 cm for men and ≥85 cm for women.

RESULTS

During a median follow-up of 9.06 years, 1336 participants developed type 2 diabetes. At baseline, the mean age was 52.1 years and the mean BMI was 24.4 kg/m². The mean MMI for men and women was 32.1% and 26.0%, respectively. There was an inverse association between MMI and the risk of type 2 diabetes. Multivariate-adjusted HRs for the risk of developing type 2 diabetes were 2.05 (95% CI 1.73, 2.43), 1.39 (95% CI 1.17, 1.66) and 1.0 from the lowest to highest sex-specific MMI tertile, with an HR of 1.35 (95% CI 1.26, 1.45) per SD decline in MMI. Further adjustments for fat mass, waist circumference and BMI as categorical variables did not modify the relationship (each p < 0.01). In BMI-stratified analyses, the population-attributable fraction of the lowest tertile of MMI for developing type 2 diabetes was increased by 11.9% in the non-obese group and 19.7% in the obese group.

CONCLUSIONS/INTERPRETATION

Low muscle mass as defined by MMI was associated with an increased risk of type 2 diabetes, independent of general obesity, in middle-aged and older Korean adults.

Irisin: A Potential Link between Physical Exercise and Metabolism-An Observational Study in Differently Trained Subjects, from Elite Athletes to Sedentary People

We compared irisin levels among groups of differently trained healthy individuals to explore the role of irisin as a physiological linker between exercise and metabolic health. Irisin and biochemical parameters of glucose and lipid metabolism were assessed in 70 healthy volunteers stratified for sport performance level into four groups: (1) 20 elite athletes of national level, (2) 20 subelite athletes of local level, (3) 20 recreational athletes, and (4) 10 sedentary subjects. All biochemical parameters were within the ranges of normality. Fasting glucose, HOMA-IR, and total cholesterol levels were inversely related to the degree of physical activity. HbA1c was higher in elite athletes compared to all the other groups (p < 0.01). A U-shaped relation between free fatty acids and the degree of physical activity was observed. All groups showed similar plasma irisin levels. After correction for the degree of insulin resistance (irisin/HOMA-IR), elite athletes showed higher levels compared to sedentary and recreational subjects (p < 0.01 and p < 0.05, resp.). In addition, the number of metabolic parameters correlated with irisin increased at increasing the training status. Our study suggests a correlation between sport performance, insulin sensitivity, and irisin levels. Irisin may be one potential mediator of the beneficial effects of exercise on metabolic profile.

Decreased muscle mass in Korean subjects with intracranial arterial stenosis: The Kangbuk Samsung Health Study

BACKGROUNDS AND AIMS

Intracranial arterial stenosis (ICAS) is a common cause of ischemic stroke in Asians. Decreased muscle mass is one of the major causes of chronic disease in adults. The purpose of this study was to analyze the relationship between muscle mass and ICAS in Korean adults.

METHODS

For this study, we selected a total of 10,530 participants (mean age, 43.3 years; 8558 men) in a health screening program, for whom transcranial Doppler (TCD) ultrasound was used to detect >50% ICAS based on criteria modified from the stroke outcomes and neuroimaging of intracranial atherosclerosis trial. Body composition was evaluated by bioelectrical impedance analysis (BIA). Skeletal muscle index (SMI) was calculated with muscle mass/weight (kg) * 100.

RESULTS

Among the total patient population, 322 (3.1%) subjects had ICAS. Subjects with ICAS were older, and had higher mean values for fasting glucose, body mass index and blood pressure compared with those without ICAS. Subjects with ICAS had significantly lower muscle mass, SMI and higher percent body fat compared with those without ICAS. In logistic regression analysis, the subjects in the highest tertile of muscle mass had the lowest odds ratio for ICAS with the lowest tertile group of muscle mass as the reference group even after adjusting for age, systolic blood pressure, fasting blood glucose, sex, smoking and exercise (OR 0.650, 95% CI 0.442-0.955).

CONCLUSIONS

Subjects with ICAS had significantly decreased muscle mass compared with those without ICAS in Korean adults. The risk for ICAS was lower in subjects with higher muscle mass.