Resistin and obesity-associated insulin resistance

Changes in serum ghrelin and resistin levels after sleeve gastrectomy versus one anastomosis gastric bypass: prospective cohort study

INTRODUCTION

Humoral factors and neural mechanisms play a central role in the pathogenesis of obesity and in weight loss following bariatric surgery. Although various hormones and adipokines, including ghrelin and resistin, are linked to obesity, studies analyzing the changes in fasting ghrelin and resistin levels in patients following one anastomosis gastric bypass (OAGB) are lacking.

AIM

The authors aimed to investigate resistin and ghrelin levels before and after two commonly used bariatric procedures with different mechanisms of action: sleeve gastrectomy (SG) and OAGB.

PATIENTS AND METHODS

Fasting serum ghrelin and resistin levels were evaluated by using ELISA in a nonrandomized, prospective cohort study for the pattern of changes in the preoperative period and 1 week, 1 month, 3 months and, 12 months after surgery in age and sex-matched patients with BMI ≥40 kg/m 2 undergoing either SG ( n =40) or OAGB ( n =40). Their relationships with demographic parameters such as body weight, BMI, presence of T2DM, HbA 1 C, and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) index were also evaluated.

RESULTS

OAGB was superior in weight control compared to the SG group. There were significant differences in resistin and ghrelin levels between the OAGB and SG groups. Ghrelin decreased more in the SG group than the preoperative values. This change in ghrelin levels was more significant at 1 year after SG [preoperative mean (range) level of 334.2 (36.6-972.1) pg/ml decreased to 84 (9.1-227) pg/ml at 1 year] whereas in the OAGB group no significant change was observed [preoperative mean (range) level of 310 (146-548) pg/ml decreased to 264 (112-418) pg/ml at 1 year]. Resistin levels decreased in both groups, especially after 3 months and onward following both operations [the mean (range) resistin levels were 2.6 (0.87-5.4) ng/ml and decreased to 1.1 (0.5-2.4) ng/ml in the SG group vs 2.48 (0.89-6.43) ng/ml decreased to 0.72 (0.35-1.8) ng/ml in OAGB group at 1 year], which was in parallel with changes in HOMA-IR index, body weight, and BMI changes at 1st year. HOMA-IR index changes were similar, but more prominent after OAGB. OAGB was als3 three months and onward), and HOMA-IR changes.

CONCLUSION

This is the first study to compare fasting ghrelin and resistin levels after OAGB and SG. Although similar changes were observed, ghrelin changes were more prominent after SG, whereas resistin were observed after OAGB. OAGB was superior in T2DM control, which was in parallel with weight loss, fasting resistin levels, and HOMA-IR changes suggesting a possible effect of resistin after OAGB in glucose metabolism and insulin resistance.

The Effects of Different Dietary Patterns on Bone Health

Bone metabolism is a process in which osteoclasts continuously clear old bone and osteoblasts form osteoid and mineralization within basic multicellular units, which are in a dynamic balance. The process of bone metabolism is affected by many factors, including diet. Reasonable dietary patterns play a vital role in the prevention and treatment of bone-related diseases. In recent years, dietary patterns have changed dramatically. With the continuous improvement in the quality of life, high amounts of sugar, fat and protein have become a part of people's daily diets. However, people have gradually realized the importance of a healthy diet, intermittent fasting, calorie restriction, a vegetarian diet, and moderate exercise. Although these dietary patterns have traditionally been considered healthy, their true impact on bone health are still unclear. Studies have found that caloric restriction and a vegetarian diet can reduce bone mass, the negative impact of a high-sugar and high-fat dietary (HSFD) pattern on bone health is far greater than the positive impact of the mechanical load, and the relationship between a high-protein diet (HPD) and bone health remains controversial. Calcium, vitamin D, and dairy products play an important role in preventing bone loss. In this article, we further explore the relationship between different dietary patterns and bone health, and provide a reference for how to choose the appropriate dietary pattern in the future and for how to prevent bone loss caused by long-term poor dietary patterns in children, adolescents, and the elderly. In addition, this review provides dietary references for the clinical treatment of bone-related diseases and suggests that health policy makers should consider dietary measures to prevent and treat bone loss.

New Mediators in the Crosstalk between Different Adipose Tissues

Adipose tissue is a multifunctional organ that regulates many physiological processes such as energy homeostasis, nutrition, the regulation of insulin sensitivity, body temperature, and immune response. In this review, we highlight the relevance of the different mediators that control adipose tissue activity through a systematic review of the main players present in white and brown adipose tissues. Among them, inflammatory mediators secreted by the adipose tissue, such as classical adipokines and more recent ones, elements of the immune system infiltrated into the adipose tissue (certain cell types and interleukins), as well as the role of intestinal microbiota and derived metabolites, have been reviewed. Furthermore, anti-obesity mediators that promote the activation of beige adipose tissue, e.g., myokines, thyroid hormones, amino acids, and both long and micro RNAs, are exhaustively examined. Finally, we also analyze therapeutic strategies based on those mediators that have been described to date. In conclusion, novel regulators of obesity, such as microRNAs or microbiota, are being characterized and are promising tools to treat obesity in the future.

Bariatric Surgery in Obesity: Metabolic Quality Analysis and Comparison of Surgical Options

Obesity is a constantly growing health problem which reduces quality of life and life expectancy. Bariatric surgery (BS) for obesity is considered when all other conservative treatment modalities have failed. Comparison of the multidisciplinary programs with BS regarding to the weight loss showed that substantial and durable weight reduction have been achieved only with bariatric surgical treatments. Although laparoscopic sleeve gastrectomy is the most popular BS, it has high long-term failure rates, and it is claimed that one of every three patients will undergo another bariatric procedure within a 10-year period. Although BS provides weight loss and improvement of metabolic comorbidities, in long-term follow-up, weight gain is observed in half of the patients, while decrease in bone mass and nutritional deficiencies occur in up to 90%. Moreover, despite significant weight loss, several psychological aspects of patients are worsened in comparison to preoperative levels. Nearly one-fifth of postoperative patients with "Loss-of-eating control" meet food addiction criteria. Therefore, the benefits of weight loss following bariatric procedures alone are still debated in terms of the proinflammatory and metabolic profile of obesity.

Anterior Pituitary Transcriptomics Following a High-Fat Diet: Impact of Oxidative Stress on Cell Metabolism

Anterior pituitary cell function requires a high level of protein synthesis and secretion which depend heavily on mitochondrial adenosine triphosphate production and functional endoplasmic reticula. Obesity adds stress to tissues, requiring them to adapt to inflammation and oxidative stress, and adding to their allostatic load. We hypothesized that pituitary function is vulnerable to the stress of obesity. Here, we utilized a 10- to 15-week high-fat diet (HFD, 60%) in a thermoneutral environment to promote obesity, testing both male and female FVB.129P mice. We quantified serum hormones and cytokines, characterized the metabolic phenotype, and defined changes in the pituitary transcriptome using single-cell RNA-sequencing analysis. Weight gain was significant by 3 weeks in HFD mice, and by 10 weeks all HFD groups had gained 20 g. HFD females (15 weeks) had increased energy expenditure and decreased activity. All HFD groups showed increases in serum leptin and decreases in adiponectin. HFD caused increased inflammatory markers: interleukin-6, resistin, monocyte chemoattractant protein-1, and tumor necrosis factorα. HFD males and females also had increased insulin and increased TSH, and HFD females had decreased serum prolactin and growth hormone pulse amplitude. Pituitary single-cell transcriptomics revealed modest or no changes in pituitary cell gene expression from HFD males after 10 or 15 weeks or from HFD females after 10 weeks. However, HFD females (15 weeks) showed significant numbers of differentially expressed genes in lactotropes and pituitary stem cells. Collectively, these studies reveal that pituitary cells from males appear to be more resilient to the oxidative stress of obesity than females and identify the most vulnerable pituitary cell populations in females.

Resistin serum levels and its association with clinical profile and carotid intima-media thickness in psoriasis: a cross-sectional study

BACKGROUND

Psoriasis is a protean disease associated with several comorbidities that may have increased levels of adiponectin such as resistin. This may affect the patients atherosclerotic risk.

OBJECTIVE

To study resistin levels in a sample of Brazilian patients with psoriasis and its association with clinical profile, comorbidities, and carotid Intima-Media Thickness (cIMT).

METHODS

This is a cross-sectional study of 119 individuals: 34 healthy controls and 85 patients with psoriasis, 42 of which with skin involvement only and 43 with psoriatic arthritis. Clinical and epidemiological data, measurement of PASI (Psoriasis Area Severity Index) and DAPSA (Disease Activity in Psoriatic Arthritis), lipid profile, cIMT by ultrasound were collected from medical records. Resistin serum levels were measured by ELISA.

RESULTS

Patients with psoriasis had higher resistin levels (p=0.009) and worse cIMT (p=0.0002) than controls. In the psoriasis sample, no associations of resistin levels with epidemiological, clinical findings, and activity indexes were found. Resistin serum levels were associated with the presence of diabetes (p=0.008) and metabolic syndrome (p=0.01) and correlated with total cholesterol (r=0.26) and triglycerides (r=0.33) but not with cIMT.

STUDY LIMITATIONS

This work is limited by its transversal design and by the limited number of patients included.

CONCLUSION

Resistin serum levels are elevated in psoriasis patients. In this sample, clinical, epidemiological, and activity indexes were not linked to resistin serum levels, but atherosclerotic risk factors were.

Adipokines and Their Role in Heart Failure: A Literature Review

Obesity is a major risk factor for heart failure (HF). The relationship between adipokines and HF has been implicated in many previous studies and reviews. However, this review article summarizes the basic role of major adipokines, such as apelin, adiponectin, chemerin, resistin, retinol-binding protein 4 (RBP4), vaspin, visfatin, plasminogen activator inhibitor-1, monocyte chemotactic protein-1, nesfatin-1, progranulin, leptin, omentin-1, lipocalin-2, and follistatin-like 1 (FSTL1), in the pathogenesis of HF. Apelin is reduced in patients with HF and upregulated following favorable left ventricular (LV) remodeling. Higher levels of adiponectin have been found in patients with HF compared to in control patients. Also, high plasma chemerin levels are linked to a higher risk of HF. Serum resistin is related to the severity of HF and associated with a high risk for adverse cardiac events. Evidence indicates that RBP4 can contribute to inflammation and damage heart muscle cells, potentially leading to HF. Vaspin might stop the progression of cardiac degeneration, fibrosis, and HF according to experiments on rats with experimental isoproterenol-induced chronic HF. The serum concentrations of visfatin are significantly lower in patients with systolic HF. Leptin levels were found to be correlated with low LV mass and myocardial stiffness, both of which are significant risk factors for the development of HF with preserved ejection fraction (HFpEF). Measuring serum omentin-1 levels appears to be a novel prognostic indicator for risk stratification in HF patients. Increased expression of neutrophil gelatinase-associated lipocalin in both systemic circulation and myocardium in clinical and experimental HF suggests that innate immune responses may contribute to the development of HF. FSTL1 was elevated in patients with HF with reduced ejection fraction and associated with an increase in the size of the left ventricle of the heart. However, other adipokines, such as plasminogen activator inhibitor-1, monocyte chemotactic protein-1, nesfatin-1, and progranulin, have not yet been studied for HF.

Adipokines as Clinically Relevant Therapeutic Targets in Obesity

Adipokines provide an outstanding role in the comprehensive etiology of obesity and may link adipose tissue dysfunction to further metabolic and cardiovascular complications. Although several adipokines have been identified in terms of their physiological roles, many regulatory circuits remain unclear and translation from experimental studies to clinical applications has yet to occur. Nevertheless, due to their complex metabolic properties, adipokines offer immense potential for their use both as obesity-associated biomarkers and as relevant treatment strategies for overweight, obesity and metabolic comorbidities. To provide an overview of the current clinical use of adipokines, this review summarizes clinical studies investigating the potential of various adipokines with respect to diagnostic and therapeutic treatment strategies for obesity and linked metabolic disorders. Furthermore, an overview of adipokines, for which a potential for clinical use has been demonstrated in experimental studies to date, will be presented. In particular, promising data revealed that fibroblast growth factor (FGF)-19, FGF-21 and leptin offer great potential for future clinical application in the treatment of obesity and related comorbidities. Based on data from animal studies or other clinical applications in addition to obesity, adipokines including adiponectin, vaspin, resistin, chemerin, visfatin, bone morphogenetic protein 7 (BMP-7) and tumor necrosis factor alpha (TNF-α) provide potential for human clinical application.

Gpr75-deficient mice are protected from high-fat diet-induced obesity

OBJECTIVE

G-protein coupled receptor 75 (GPR75) has been identified as the high-affinity receptor of 20-hydroxyeicosatetraenoic acid (20-HETE), a vasoactive and proinflammatory lipid, and mice overproducing 20-HETE have been shown to develop insulin resistance when fed a high-fat diet (HFD), which was prevented by a 20-HETE receptor blocker. Simultaneously, a large-scale exome sequencing of 640,000 subjects identified an association between loss-of-function GPR75 variants and protection against obesity.

METHODS

Wild-type (WT) and Gpr75-deficient mice were placed on HFD for 14 weeks, and their obesity phenotype was examined.

RESULTS

Male and female Gpr75 null (knockout [KO]) and heterozygous mice gained less weight than WT mice when placed on HFD. KO mice maintained the same level of energy expenditure during HFD feeding, whereas WT mice showed a significant reduction in energy expenditure. Diet-driven adiposity and adipocyte hypertrophy were greatly lessened in Gpr75-deficient mice. HFD-fed KO mice did not develop insulin resistance. Adipose tissue from Gpr75-deficient mice had increased expression of thermogenic genes and decreased levels of inflammatory markers. Moreover, insulin signaling, which was impaired in HFD-fed WT mice, was unchanged in KO mice.

CONCLUSIONS

These findings suggest that GPR75 is an important player in the control of metabolism and glucose homeostasis and a likely novel therapeutic target to combat obesity-driven metabolic disorders.

Hepatokines and Adipokines in Metabolic Syndrome

Hepatokines and adipokines are secretory proteins derived from hepatocytes and adipocytes, respectively. These proteins play a main role in the pathogenesis of metabolic syndrome (MetS), characterized by obesity, dysglycemia, insulin resistance, dyslipidemia, and hypertension. Adipose tissue and liver are important endocrine organs because they regulate metabolic homeostasis as well as inflammation because they secrete adipokines and hepatokines, respectively. These adipokines and hepatokines communicate their action through different autocrine, paracrine and endocrine pathways. Liver regulates systemic homeostasis and also glucose and lipid metabolism through hepatokines. Dysregulation of hepatokines can lead to progression toward MetS, type 2 diabetes (T2D), inflammation, hypertension, and other diseases. Obesity is now a worldwide epidemic. Increasing cases of obesity and obesity-associated metabolic syndrome has brought the focus on understanding the biology of adipocytes and the mechanisms occurring in adipose tissue of obese individuals. A lot of facts are now available on adipose tissue as well. Adipose tissue is now given the status of an endocrine organ. Recent evidence indicates that obesity contributes to systemic metabolic dysfunction. Adipose tissue plays a significant role in systemic metabolism by communicating with other central and peripheral organs via the production and secretion of a group of proteins known as adipokines. Adipokine levels regulate metabolic state of our body and are potent enough to have a direct impact upon energy homeostasis and systemic metabolism. Dysregulation of adipokines contribute to obesity, T2D, hypertension and several other pathological changes in various organs. This makes characterization of hepatokines and adipokines extremely important to understand the pathogenesis of MetS. Hepatokines such as fetuin-A and leukocyte cell-derived chemotaxin 2, and adipokines such as resistin, leptin, TNF-α, and adiponectin are some of the most studied proteins and they can modulate the manifestations of MetS. Detailed insight into the function and mechanism of these adipokines and hepatokines in the pathogenesis of MetS can show the path for devising better preventative and therapeutic strategies against this present-day pandemic.

Ergosterol fraction from Agaricus bisporus modulates adipogenesis and skeletal glucose uptake in high fat diet induced obese C57BL/6 mice

AIM

The study aimed to optimize a method of extracting ergosterol rich concentrate (ECF) and to evaluate its significant impact on adipogenesis and associated complications in high-fat diet (HFD) induced obese mice.

METHODS

A comparative analysis (soxhlet and ultra sound assisted extraction) was done to obtain the highest yield of ergosterol from Agaricus bisporus. The ECF was evaluated for the biological effect on 3T3-L1 pre-adipocytes in-vitro and in male C57BL/6 mice model in-vivo.

KEY FINDINGS

Ultra sound assisted extraction method using the solvent n-hexane resulted in highest ergosterol yield. ECF treatment significantly reduced the differentiation and lipid accumulation in pre-adipocyte cells without any cytotoxicity. In-vivo study illustrated beneficial impact on cholesterol metabolism by down regulating the hepatic gene expression of LXR-α, HMG-CoR and up-regulating LDL-R expression. Significant increase in fecal excretion of cholesterol and bile acids have also been observed among the ECF treated animals compared to high fat diet (HFD) fed mice. ECF had an anti-adipogenic activity in-vivo mainly by inhibiting the activity of PPAR-γ, C/EBP-α and SREBP-1c. The results also depicted the improvement of obesity associated insulin resistance by ECF treatment manly via decrease in plasma resistin and up-regulation in skeletal GLUT4 protein expression.

SIGNIFICANCE

Our study illustrated diverse activity of ECF in the therapeutic management of obesity associated metabolic complications mainly by reducing adipogenesis and improving glucose uptake in skeletal muscle in conjunction with improved cholesterol metabolism.

The Effect of Exercise on Serum Resistin and Leptin Values in Rats Fed with a High Fat Diet

Aim: This study was performed to investigate the effect of exercise on serum resistin and leptin values in rats fed with a high-fat diet. Material and Method: 24 Wistar albino male rats were used in the study. They were randomly divided into 4 groups, with 6 rats in each group. The groups were determined as the control group (C), exercise group (E), high-fat diet (HFD) group, and high-fat diet + exercise (HFDE) Group. Results: When the findings obtained in this study were evaluated statistically, it was determined that the resistin values were similar in the C, E and HFDE groups, and higher in the HFD group compared to the other groups. It was observed that resistin value increased with high-fat diet and decreased with exercise. When evaluated in terms of leptin levels, the C and E groups showed similarity, while the HFD and HFDE groups showed similarity with each other. Although exercise decreased the leptin level, which was highly increased with a high-fat diet, it was not statistically significant. Conclusion: It has been determined that feeding with a high-fat diet causes an increase in serum resistin and leptin levels, and exercise provides a significant decrease in resistin values, but is not effective in leptin levels.

Association between circulating resistin levels and thyroid dysfunction: A systematic review and meta-analysis

Background

As a product of adipose tissue, resistin exceeds other adipokines in its role in regulating appetite, energy expenditure, insulin sensitivity, inflammation, and immunity, similar to thyroid hormones. This study aimed to evaluate the association between resistin levels and thyroid dysfunction and to explore variations in circulating resistin levels before and after treatment for thyroid dysfunction.

Methods

This study was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. A comprehensive search of PubMed, Embase, and Cochrane databases was conducted until June 15, 2022, with no start date restriction, according to the preregistered protocol (PROSPERO-CRD42022336617). RevMan version 5.4 and R software package version 4.2.0 were used for statistical analyses.

Results

Fourteen studies with 1716 participants were included in this study. The findings of the meta-analysis confirmed that the resistin levels of patients with thyroid dysfunction were significantly higher than those of the euthyroid function control group (mean difference [MD] = 2.11, 95% confidence interval [CI] = 1.11-3.11, P < 0.00001). Furthermore, the resistin levels of patients with hyperthyroidism (MD = 3.23, 95% CI = 0.68-5.79, P = 0.01) and subclinical hypoidism (MD = 1.37, 95% CI = 0.31-2.42, P = 0.01) were significantly higher than those of euthyroid controls. The resistin levels of patients with thyroid dysfunction after treatment were significantly lower than those before treatment (MD = 1.00, 95% CI = 0.34-1.65, P = 0.003), especially in patients with hyperthyroidism (MD = 2.16, 95% CI = 1.00-3.32, P = 0.0003). Correlation analysis confirmed a positive correlation between resistin levels and free triiodothyronine (FT3) levels in patients with thyroid dysfunction (r = 0.27578, P = 0.001).

Conclusions

Our meta-analysis demonstrates that resistin levels are significantly higher in patients with thyroid dysfunction, and the resistin levels after treatment in patients with thyroid dysfunction are significantly lower than those before treatment. Correlation analysis shows a positive correlation between resistin levels and FT3 levels in patients with thyroid dysfunction.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022336617.

Resistin gene expression: Novel study in dromedary camel (Camelus dromedarius)

Resistin, an adipocyte-specific hormone involved in insulin resistance and adipocyte differentiation, was initially identified in adipose tissue and macrophages. The physiological role of this molecule in camels remains largely unexplored. This study analysed for the first time blood and tissue levels of resistin as well as expression of resistin gene by real time PCR in adipose tissue (hump, visceral & epididymal) and different muscles (gastrocnemius, heart and caecum) in dromedary camels. The results revealed that resistin concentration was significantly (P<0.01) higher in epididymal adipose tissue as compared to other tissues and the lowest concentration was detected in serum. Additionally, the differential mRNA expression levels of resistin gene showed the highest expression level in epididymal adipose tissue as compared to other tissues. In conclusion, the results demonstrated for the first time that resistin was expressed in different tissues of dromedary camels. These data underscore an important facet of the physiological role of resistin as a factor involved in insulin resistance and glucose metabolism in camels.

Self-reported dietary omega-3 polyunsaturated fatty acids are associated with adipose tissue markers and glucose metabolism in apparently healthy subjects

BACKGROUND

Plasminogen activator inhibitor 1 (PAI-1) and resistin are associated with dysfunctional adipose tissue (AT)-related metabolic complications. The role of dietary eicosapentaenoic (EPA) and docosahexaenoic (DHA) fatty acids in this relationship is unknown.

AIM

To investigate the association of EPA and DHA with PAI-1 and resistin, as well as the role of this association on the glucose metabolism of apparently healthy subjects.

SUBJECTS AND METHODS

Thirty-six healthy individuals were included. Validated food frequency questionnaires were used to analyse dietary habits. Inflammatory and glucose metabolism markers were quantified. Subcutaneous AT samples were obtained, and adipocyte number, area, and macrophage content were assessed.

RESULTS

In 36 subjects aged 56 ± 8 years and with a body mass index of 26 ± 4 kg/m², _logEPA, and _logDHA showed significant association with _logresistin and a marginal association with PAI-1. Adipocyte number, area, and _lognumber of macrophages per adipocyte significantly correlated with PAI-1 but not with _logresistin. Although _logEPA and _logDHA were independently associated with _loginsulin, _loginsulin resistance, and C-Peptide, the addition of _logresistin, but not of PAI-1, into the multivariable model, abolished the associations.

CONCLUSIONS

EPA and DHA could modulate glucose metabolism across AT functional states. Our data indicate that this association is independent of other metabolic risk factors.

Kutkin, iridoid glycosides enriched fraction of Picrorrhiza kurroa promotes insulin sensitivity and enhances glucose uptake by activating PI3K/Akt signaling in 3T3-L1 adipocytes

BACKGROUND

Therapeutic failure and drug resistance are common sequelae to insulin resistance associated with type 2 diabetes mellitus (T2DM). Consequently, there is an unmet need of alternative strategies to overcome insulin resistance associated complications.

PURPOSE

To demonstrate whether Kutkin (KT), iridoid glycoside enriched fraction of Picrorhiza kurroa extract (PKE) has potential to increase the insulin sensitivity vis à vis glucose uptake in differentiated adipocytes.

METHODS

Molecular interaction of KT phytoconstituents, picroside-I (P-I) & picroside- II (P-II) with peroxisome proliferator-activated receptor gamma (PPARγ), phosphatidylinositol 3-kinase (PI3K) and protein kinase B (Akt) were analyzed in silico. Cellular viability and adipogenesis were determined by following 3-(4, 5-Dimethylthiazol-2-Yl)-2, 5-Diphenyltetrazolium bromide (MTT) assay and Oil Red-O staining. Further, ELISA kit based triglycerides and diacylglycerol-O-Acyltransferase-1 (DGAT1) were assessed in differentiated adipocytes. ELISA based determination were performed to check the levels of adiponectin and tumor necrosis factor alpha (TNF-α). However, Flow cytometry and immunofluorescence based assays were employed to measure the glucose uptake and glucose transporter 4 (glut4) expression in differentiated adipocytes, respectively. Further to explore the targeted signaling axis, mRNA expression levels of PPARγ, CCAAT/enhancer binding protein α (CEBPα), and glut4 were determined using qRT-PCR and insulin receptor substrate-1 (IRS-1), Insulin receptor substrate-2 (IRS-2), PI3K/Akt, AS160, glut4 followed by protein validation using immunoblotting in differentiated adipocytes.

RESULTS

In silico analysis revealed the binding affinities of major constituents of KT (P-I& P-II) with PPARγ/PI3K/Akt. The enhanced intracellular accumulation of triglycerides with concomitant activation of PPARγ and C/EBPα in KT treated differentiated adipocytes indicates augmentation of adipogenesis in a concentration-dependent manner. Additionally, at cellular level, KT upregulated the expression of DAGT1, and decreases fatty acid synthase (FAS), and lipoprotein lipase (LPL), further affirmed improvement in lipid milieu. It was also observed that KT upregulated the levels of adiponectin and reduced TNFα expression, thus improving the secretory functions of adipocytes along with enhanced insulin sensitivity. Furthermore, KT significantly promoted insulin mediated glucose uptake by increasing glut4 translocation to the membrane via PI3/Akt signaling cascade. The results were further validated using PI3K specific inhibitor, wortmannin and findings revealed that KT treatment significantly enhanced the expression and activation of p-PI3K/PI3K and p-Akt/Akt even in case of treatment with PI3K inhibitor wortmannin alone and co-treatment with KT in differentiated adipocytes and affirmed that KT as activator of PI3K/Akt axis in the presence of inhibitor as well.

CONCLUSION

Collectively, KT fraction of PKE showed anti-diabetic effects by enhancing glucose uptake in differentiated adipocytes via activation of PI3K/Akt signaling cascade. Therefore, KT may be used as a promising novel natural therapeutic agent for managing T2DMand to the best of our knowledge, this is the first report, showing the efficacy and potential molecular mechanism of KT in enhancing insulin sensitivity and glucose uptake in differentiated adipocytes.

Implications of Adipose Tissue Content for Changes in Serum Levels of Exercise-Induced Adipokines: A Quasi-Experimental Study

Human adipocytes release multiple adipokines into the bloodstream during physical activity. This affects many organs and might contribute to the induction of inflammation. In this study, we aimed to assess changes in circulating adipokine levels induced by intense aerobic and anaerobic exercise in individuals with different adipose tissue content. In the quasi-experimental study, 48 male volunteers (aged 21.78 ± 1.98 years) were assigned to groups depending on their body fat content (BF): LBF, low body fat (<8% BF, n = 16); MBF, moderate body fat (8−14% BF, n = 19); and HBF, high body fat (>14% BF, n = 13). The volunteers performed maximal aerobic effort (MAE) and maximal anaerobic effort (MAnE) exercises. Blood samples were collected at five timepoints: before exercise, immediately after, 2 h, 6 h, and 24 h after each exercise. The selected cytokines were analyzed: adiponectin, follistatin-like 1, interleukin 6, leptin, oncostatin M, and resistin. While the participants’ MAnE and MAE performance were similar regardless of BF, the cytokine response of the HBF group was different from that of the others. Six hours after exercise, leptin levels in the HBF group increased by 35%. Further, immediately after MAnE, resistin levels in the HBF group also increased, by approximately 55%. The effect of different BF was not apparent for other cytokines. We conclude that the adipokine exercise response is associated with the amount of adipose tissue and is related to exercise type.

Artemisia annua L. Extracts Improved Insulin Resistance via Changing Adiponectin, Leptin and Resistin Production in HFD/STZ Diabetic Mice

Objectives

Insulin resistance (IR) is major cause of type 2 diabetes (T2D), and adipokines (e.g., adiponectin, leptin, and resistin) play an important role in insulin sensitivity. Medicinal plants are frequently used for T2D treatment. This study investigates the effect of Artemisia annua L. (AA) extracts on adipokines in mice with high-fat-diet (HFD)/streptozotocin (STZ)-induced T2D.

Methods

We divided 60 mice into 12 groups (n = 5 per group) control, untreated T2D, treated T2D, and 9 other groups. T2D was induced in all groups, except controls, by 8 weeks of HFD and STZ injection. The treated T2D group was administered 250 mg/kg of metformin (MTF), while the nine other groups were treated with 100, 200, and 400 mg/kg of hot-water extract (HWE), cold-water extract (CWE), and alcoholic extract (ALE) of AA (daily oral gavage) along with 250 mg/kg of MTF for 4 weeks. The intraperitoneal glucose tolerance test (IPGTT) was performed, and the homeostasis model assessment of adiponectin (HOMA-AD) index and blood glucose and serum insulin, leptin, adiponectin, and resistin levels were measured.

Results

Similar to MTF, all three types of AA extracts (HWEs, CWEs, and ALEs) significantly (p < 0.0001) decreased the area under the curve (AUC) of glucose during the IPGTT, the HOMA-AD index, blood glucose levels, and serum insulin, leptin, and resistin levels and increased serum adiponectin levels in the MTF group compared to the T2D group (p < 0.0001). The HWEs affected adipokine release, while the CWEs and ALEs decreased leptin and resistin production.

Conclusion

Water and alcoholic AA extracts have an antihyperglycemic and antihyperinsulinemic effect on HFD/STZ diabetic mice. In addition, they decrease IR by reducing leptin and resistin production and increasing adiponectin secretion from adipocytes.

Resistin Associated With Cytokines and Endothelial Cell Adhesion Molecules Is Related to Worse Outcome in COVID-19

Introduction

Resistin is reported to form a cytokine network and cause endothelial damage. The pathogenesis of coronavirus disease 2019 (COVID-19) remains unknown, but the association between cytokine storm and endothelial damage is crucial. This study aimed to evaluate resistin in COVID-19 pathogenesis compared with sepsis.

Materials and Methods

First, we evaluated the association of plasma resistin levels and disease severity and clinical outcome in two large cohorts: a publicly available cohort including 306 COVID-19 patients in the United States (MGH cohort) and our original cohort including only intubated 113 patients in Japan (Osaka cohort 1). Second, to understand pathogenesis, we evaluate resistin, cytokines and endothelial cell adhesion molecules in COVID-19 compared with sepsis. Blood samples were collected from 62 ICU-treated COVID-19 patients and 38 sepsis patients on day 1 (day of ICU admission), days 2-3, days 6-8, and from 18 healthy controls (Osaka cohort 2). The plasma resistin, inflammatory cytokines (IL-6, IL-8, MCP-1 and IL-10) and endothelial cell adhesion molecules (ICAM-1 and VCAM-1) were compared between patients and control. Correlations among resistin, inflammatory cytokines and endothelial cell adhesion molecules were evaluated in COVID-19 and sepsis.

Results

In the MGH cohort, the day 1 resistin levels were associated with disease severity score. The non-survivors showed significantly greater resistin levels than survivors on days 1, 4 and 8. In the Osaka cohort 1, 28-day non-survivors showed significantly higher resistin levels than 28-day survivors on days 6-8. Patients with late recovery (defined as the day of weaning off mechanical ventilation >12 or death) had significantly higher resistin levels than those with early recovery on day 1 and days 6-8. In the Osaka cohort 2, plasma resistin levels were elevated in COVID-19 and sepsis patients compared to controls at all measurement points and were associated with inflammatory cytokines and endothelial cell adhesion molecules.

Conclusion

Resistin was elevated in COVID-19 patients and was associated with cytokines and endothelial cell adhesion molecules. Higher resistin levels were related to worse outcome.

Obesity: A Chronic Low-Grade Inflammation and Its Markers

As the prevalence of obesity continues to rise, the world is facing a major public health concern. Obesity is a complex disease associated with an increase in several inflammatory markers, leading to chronic low-grade inflammation. Of multifactorial etiology, it is often used as a measurement of morbidity and mortality. There remains much unknown regarding the association between obesity and inflammation. This review seeks to compile scientific literature on obesity and its associated inflammatory markers in chronic disease and further discusses the role of adipose tissue, macrophages, B-cells, T-cells, fatty acids, amino acids, adipokines, and hormones in obesity. Data were obtained using PubMed and Google Scholar. Obesity, inflammation, immune cells, hormones, fatty acids, and others were search words used to acquire relevant articles. Studies suggest brown adipose tissue is negatively associated with body mass index (BMI) and body fat percentage. Researchers also found the adipose tissue of lean individuals predominantly secretes anti-inflammatory markers, while in obese individuals more pro-inflammatory markers are secreted. Many studies found that adipose tissue in obese individuals showed a shift in immune cells from anti-inflammatory M2 macrophages to pro-inflammatory M1 macrophages, which was also correlated with insulin resistance. Obese individuals generally present with higher levels of hormones such as leptin, visfatin, and resistin. With obesity on the rise globally, it is predicted that severe obesity will become most common amongst low-income adults, black individuals, and women by 2030, making the need for intervention urgent. Further investigation into the association between obesity and inflammation is required to understand the mechanism behind this disease.

An immediate post op and follow up assessment of circulating adipo-cytokines after bariatric surgery in morbid obesity

Background

Bariatric surgery has emerged as a promising treatment for improving adipose tissue dysfunction in obesity, but the mechanisms for such amelioration are still not known. This study comprehensively explores a panel of adipo-cytokines in individuals with obesity undergoing bariatric surgery, in conjunction with markers of insulin resistance, at three time points i.e., pre-op, immediate post-op and 6 months post-surgery.

Methods

It is a case-control prospective study among obese individuals undergoing bariatric surgery (BMI ≥35 kg/m2, n=30) and non-obese subjects (BMI <25 kg/m2, n=30), comparing the levels of serum adiponectin, resistin, C-Reactive Protein (CRP), Interleukin (IL)-6 and 8, Monocyte chemoattractant protein (MCP)-1 and Tumor necrosis factor (TNF)-α between them. The same were followed at immediate and 6-month post-op periods in the former group. The serum markers were correlated with the markers of Insulin resistance like HOMA-IR, HOMA-β and QUICKI.

Results

A significant increase in adiponectin was seen after weight loss in obese group (17.54 ± 1.31 μg/mL at baseline vs 68.76 ± 1.84 μg/mL at 6- month post-surgery). CRP being an acute phase protein showed significant higher levels at immediate post-op period but declined even below its baseline at 6 months after surgery (33.34 ± 16.85 μg/mL at baseline vs 59.85 ± 23.12 μg/mL at immediate post-op vs 9.66 ± 1.84 μg/mL at 6 months post-operatively). Few inconsistencies were observed in the trajectories of IL-6 and TNF-α, while other pro-inflammatory markers indicated resolution after surgery.

Conclusion

Bariatric surgery alleviated the systemic inflammation, correlating with improved insulin resistance in individuals with obesity.

What is already known about this subject?•

There is an altered expression of inflammatory cytokines and adipokines in obesity, contributing to a low-grade chronic inflammation, culminating in adipose tissue dysfunction.

•

Bariatric surgery leads to a considerable reduction in the adipose tissue mass which leads in resolution of inflammation, in terms of circulating adipocytokines.

•

The adipokines and cytokine profiles have been investigated pre and post bariatric surgery but inconsistencies have been reported in their serum levels in various studies.

What this study adds?•

This study takes into account the immediate post-operative serum cytokine profile, which has not been reported in the literature yet.

•

This study reports the significant changes in said parameters, right from the beginning of the post-surgical period, and correlates it with clinical profile of subjects.

•

This further enhances the knowledge about translation of bariatric surgery induced biochemical alterations, into a significant clinical benefit with regard to obesity related morbidity and mortality.

Obesity and insulin resistance: Pathophysiology and treatment

The prevalence of obesity is a major cause of many chronic metabolic disorders, including type 2 diabetes mellitus (T2DM), cardiovascular disease (CVD), and cancer. Insulin resistance is often associated with metabolic unhealthy obesity (MUO). Therapeutic approaches aiming to improve insulin sensitivity are believed to be central for the prevention and treatment of MUO. However, current antiobesity drugs are reported as multitargeted and their insulin-sensitizing effects remain unclear. In this review, we discuss current understanding of the mechanisms of insulin resistance from the aspects of endocrine disturbance, inflammation, oxidative, and endoplasmic reticulum stress (ERS). We then summarize the antiobesity drugs, focusing on their effects on insulin sensitivity. Finally, we discuss strategies for obesity treatment.

Adipocytokine Profile Reveals Resistin Forming a Prognostic-Related Cytokine Network in the Acute Phase of Sepsis

INTRODUCTION

Cytokines compose a network and play crucial roles in the pathogenesis and prognosis of sepsis. Adipose tissue is an important immune endocrine organ that releases adipocytokines. This study aimed to evaluate adipocytokines in sepsis from a network perspective.

MATERIALS AND METHODS

This retrospective study of 37 patients with sepsis and 12 healthy controls was conducted from February 2014 to July 2015. Blood samples were collected from patients on days 1 (within 24 h of diagnosis), 2, 4, 6, 8, 11, and 15 and from healthy controls. Adipocytokines (adiponectin, leptin, resistin, chemerin, visfatin, vaspin, CXCL-12/SDF-1, angiotensinogen), inflammatory cytokines (IL-1β, IL-4, IL-6, IL-8, IL-10, IL-12/IL-23p40, TNF-α, monocyte chemotactic protein [MCP-1]), and plasminogen activator inhibitor-1 were measured. Acute Physiology and Chronic Health Evaluation II score was evaluated on day 1, and Sequential Organ Failure Assessment (SOFA) score and Japanese Association for Acute Medicine (JAAM) and International Society of Thrombosis and Hemostasis overt disseminated intravascular coagulation (DIC) scores were assessed at the times of blood sampling.

RESULTS

Hierarchical clustering analysis showed the cluster formed by resistin, IL-6, IL-8, MCP-1, and IL-10 on days 1, 2, and 4 represented the cytokine network throughout the acute phase of sepsis. Each cytokine in this network was significantly associated with SOFA and JAAM DIC scores over the acute phase. A Cox proportional hazards model focusing on the acute phase showed a significant relation of these five cytokines with patient prognosis.

CONCLUSIONS

Adipocytokines and an inflammatory cytokine profile assessed over time in sepsis patients showed that resistin was involved in an inflammatory cytokine network including IL-6, IL-8, IL-10, and MCP-1 in the acute phase of sepsis, and this network was associated with severity and prognosis of sepsis.

Resistin Expression in Epithelial Ovarian Cancer promotes the Proliferation and Migration of Ovarian Cancer Cells to Worsen Prognosis

Background: Epithelial ovarian cancer (EOC) is the most common gynecological cancer in women. Resistin, an inflammatory adipocytokine, is associated with obesity, insulin resistance, and various cancer types.

Materials and Methods: We investigated resistin expression in tissues and its association with the clinicopathological characteristics and prognosis of patients with EOC. The SKOV3 and CAOV3 cell lines were treated with exogenous resistin and rapamycin (resistin inhibitor), and the expression of mTOR in SKOV3 and CAOV3 cells was measured. Cell proliferation was measured using the CCK-8 assay. Western blotting analysis was performed to examine the phosphorylation of P70S6K and mTOR. Wound healing and Transwell analyses were conducted to examine the effect of resistin on the migration of SKOV3 and CAOV3 cells.

Results: High resistin expression was positively correlated with the pathological grade (P = 0.017) and lymph node metastasis (P = 0.045). However, resistin expression was not correlated with age, FIGO stage, or residual tumor after initial laparotomy (P > 0.05). Cox multivariate analysis showed that resistin expression was an independent factor for determining disease-free survival, whereas lymph node metastasis, resistin expression, and age (≥55 years) were independent factors affecting overall survival. Exogenous resistin induced ovarian cancer cell proliferation, whereas rapamycin had the opposite effect. Resistin promoted the proliferation of ovarian cancer cells via the mTOR signaling pathway and was associated with phosphorylating P70S6K. Furthermore, resistin promoted the migration of ovarian cancer cells.

Conclusions: Resistin may promote the occurrence of ovarian cancer and is related to the prognosis of patients. This protein may also affect the proliferation of EOC cells through the mTOR signaling pathway. Therefore, resistin shows potential as a molecular therapeutic target in ovarian cancer.

Reducing hepatic endoplasmic reticulum stress ameliorates the impairment in insulin signaling induced by high levels of β-hydroxybutyrate in bovine hepatocytes

Ketotic dairy cows exhibit a state of negative energy balance (NEB) characterized by elevated circulating levels of β-hydroxybutyrate (BHB) and fatty acids. Impaired hepatic insulin signaling in dairy cows occurs frequently during the transition into lactation, but its role on liver function during this period is not well known. In nonruminants, endoplasmic reticulum (ER) stress is a causal factor contributing to impaired insulin signaling in the liver. Thus, the aim of this study was to investigate the status of hepatic insulin and ER stress signaling and whether ER stress contributes to impaired insulin signaling in dairy cows with ketosis. Healthy (control cows, n = 10, BHB ≤0.6 mM) and ketotic (ketotic cows, n = 10, BHB ≥1.2 mM) cows at 3 to 10 d in milk were selected for liver biopsy and blood sampling before feeding. In vitro experiments were conducted with isolated hepatocytes from 5 healthy calves (1 d old, fasted female, 30-40 kg of body weight). Treatments included BHB (0, 0.9, 1.8, 3.6 mM), tauroursodeoxycholic acid (TUDCA, a canonical inhibitor of ER stress), and different incubation times (0.5, 1, 2, 3, 5, 7, 9, or 12 h). Ketotic cows had lower daily milk yield (median: 29.50 vs. 23.00 kg), higher plasma nonesterified fatty acid (NEFA) (median: 0.33 vs. 1.17 mM), BHB (median: 0.43 vs. 3.22 mM), aspartate aminotransferase (median: 70.58 vs. 155.70 U/L), alanine aminotransferase (median: 18.31 vs. 37.90 U/L), lower plasma glucose (median: 4.32 vs. 2.37 mg/dL), and revised quantitative insulin sensitivity check index (median: 0.39 vs. 0.37) compared with healthy cows. Increased abundance of phosphorylated insulin receptor substrate-1 (IRS1) and decreased abundance of phosphorylated protein kinase B (AKT) and glycogen synthase kinase-3β (GSK3β) in ketotic cows indicated a state of insulin resistance. In addition, abundance of phosphorylated protein kinase RNA-like ER kinase (PERK) and inositol requiring protein-1α (IRE1α), and cleavage of activating transcription factor-6 (ATF6) were greater in the liver of ketotic cows. In vitro, at the early stages of incubation, treatment with BHB upregulated abundance of phosphorylated of IRE1α, PERK, and the cleavage of ATF6, as well as several unfolded protein response genes [X-box-binding protein-1 (XBP1), 78 kDa glucose-regulated protein (GRP78), and C/EBP homologous protein (CHOP)]. Furthermore, in response to increasing doses of BHB, the phosphorylation level of PERK, IRE1α, and the cleavage of ATF6, and the abundance of XBP1, GRP78, and CHOP increased. In addition, BHB treatment increased phosphorylation of IRS1 and decreased phosphorylation of AKT and GSK3β, and upregulated abundance of gluconeogenic genes (phosphoenolpyruvate carboxykinase and glucose-6-phosphatase). Importantly, these changes were reversed by inhibiting ER stress with TUDCA treatment. Overall, the present study indicated that reversing ER stress during ketosis might help alleviate hepatic insulin resistance. Targeting ER stress may represent a potential therapeutic target for controlling the negative aspects of ketosis on liver function.

Blood Circulating Levels of Adipokines in Polycystic Ovary Syndrome Patients: A Systematic Review and Meta-analysis

A body of studies has examined the circulating concentration of adipokines including apelin, vapin, resistin, and chemerin in polycystic ovary syndrome (PCOS) patients. However, their findings have been inconclusive. Therefore, we systematically reviewed available studies to illuminate the overall circulating concentration of adipokines in PCOS subjects. Cochrane's Library, PubMed, Scopus, and ISI Web of Science databases were searched from the earliest available date up to April 2021 for relevant articles. The quality of each study was assessed by the Newcastle-Ottawa Quality Assessment Scale. The pooled effect size was estimated based on the random effects model, and the standard mean differences (SMD) with a 95% confidence interval (CI) were reported. A total of 88 studies met the inclusion criteria and were included in the current systematic review and meta-analysis. The results of the analysis showed that serum levels of vaspin (SMD 0.69; 95% CI, 0.22 to 1.17; P = 0.004; I² = 90.6%), chemerin (SMD 1.87; 95% CI, 1.35 to 2.40; P < 0.001; I² = 94.4%), and resistin (SMD 0.66; 95% CI, 0.41 to 0.91; P < 0.001; I² = 92.6%) were significantly higher in the PCOS group compared to controls. However, there was no significant difference between the PCOS and control groups in relation to apelin levels (SMD - 0.17; 95% CI, - 1.06 to 0.73; P = 0.714; I² = 97.8%). We found that serum levels of vaspin, chemerin, and resistin were significantly higher in PCOS subjects compared with controls. It seems that these adipokines can be measured as a useful marker to predict the development of PCOS.

Molecular Pathogenesis of Psoriasis and Biomarkers Reflecting Disease Activity

Psoriasis is a chronic inflammatory skin disease induced by multifactorial causes and is characterized by bothersome, scaly reddish plaques, especially on frequently chafed body parts, such as extensor sites of the extremities. The latest advances in molecular-targeted therapies using biologics or small-molecule inhibitors help to sufficiently treat even the most severe psoriatic symptoms and the extra cutaneous comorbidities of psoriatic arthritis. The excellent clinical effects of these therapies provide a deeper understanding of the impaired quality of life caused by this disease and the detailed molecular mechanism in which the interleukin (IL)-23/IL-17 axis plays an essential role. To establish standardized therapeutic strategies, biomarkers that define deep remission are indispensable. Several molecules, such as cytokines, chemokines, antimicrobial peptides, and proteinase inhibitors, have been recognized as potent biomarker candidates. In particular, blood protein markers that are repeatedly measurable can be extremely useful in daily clinical practice. Herein, we summarize the molecular mechanism of psoriasis, and we describe the functions and induction mechanisms of these biomarker candidates.

Resistin, a Novel Host Defense Peptide of Innate Immunity

Resistin, a cysteine-rich protein, expressed in adipocytes, was initially proposed as a link between obesity and diabetes in mice. In humans, resistin is considered to be a pro-inflammatory molecule expressed in immune cells, which plays a regulatory role in many chronic inflammatory diseases, metabolic diseases, infectious diseases, and cancers. However, increasing evidence shows that resistin functions as a host defense peptide of innate immunity, in terms of its wide-spectrum anti-microbial activity, modulation of immunity, and limitation of microbial product-induced inflammation. To date, the understanding of resistin participating in host defense mechanism is still limited. The review aims to summarize current knowledge about the biological properties, functions, and related mechanisms of resistin in host defense, which provides new insights into the pleiotropic biological function of resistin and yields promising strategies for developing new antimicrobial therapeutic agents.

Circulating resistin and follistatin levels in obese and non-obese women with polycystic ovary syndrome: A systematic review and meta-analysis

This meta-analysis was performed to resolve the inconsistencies regarding resistin and follistatin levels in women with polycystic ovary syndrome (PCOS) by pooling the available evidence. A systematic literature search using PubMed and Scopus was carried out through November 2020 to obtain all pertinent studies. Weighted mean differences (WMDs) with corresponding 95% confidence intervals (CIs) were calculated to evaluate the strength of the association between the levels of resistin and follistatin with PCOS in the overall and stratified analysis by obesity status. A total of 47 publications, 38 for resistin (2424 cases; 1906 controls) and 9 studies for follistatin (815 cases; 328 controls), were included in the meta-analysis. Resistin levels were significantly higher in PCOS women compared with non-PCOS controls (WMD = 1.96 ng/ml; 95%CI = 1.25–2.67, P≤0.001) as well as in obese PCOS women vs. obese controls, and in non-obese PCOS women compared with non-obese controls, but not in obese PCOS vs. non-obese PCOS patients,. A significantly increased circulating follistatin was found in PCOS patients compared with the controls (WMD = 0.44 ng/ml; 95%CI = 0.30–0.58, P≤0.001) and in non-obese PCOS women compared with non-obese controls and in obese PCOS women vs. obese controls, but, no significant difference in follistatin level was observed in obese PCOS compared with non-obese PCOS women. Significant heterogeneity and publication bias was evident for some analyses. Circulating levels of resistin and follistatin, independent of obesity status, are higher in women with PCOS compared with controls, showing that these adipokines may contribute to the pathology of PCOS.

Cardiovascular and Metabolic Crosstalk in the Brain: Leptin and Resistin

Leptin and resistin are cytokines whose plasma levels correlate with adiposity. Leptin is a hormone synthesised and released from adipocytes and can be transported into the brain. Resistin is produced in adipocytes in rodents and in macrophages in humans, particularly macrophages that have infiltrated adipose tissue. Both hormones can act within the brain to influence sympathetic nerve activity. Leptin appears to have a generalised sympatho-excitatory actions whilst resistin appears to increase sympathetic nerve activity affecting the cardiovascular system but inhibits sympathetic nerve activity to brown adipose tissue, which contrasts with leptin. Since both hormones can be elevated in conditions of metabolic dysfunction, interactions/crosstalk between these two hormones in the brain is a real possibility. This review describes the current knowledge regarding such crosstalk within the central nervous system. The evidence suggests that with respect to sympathetic nerve activity, crosstalk between leptin and resistin can elicit enhanced sympatho-excitatory responses to the kidneys. In contrast, with respect to food intake, resistin has weaker effects, but in regard to insulin secretion and thermogenesis, leptin and resistin have opposing actions. Thus, in conditions in which there is increased resistin and leptin levels, the result of crosstalk in the central nervous system could contribute to worse cardiovascular and metabolic complications.

Adipocytes Under Obese-Like Conditions Change Cell Cycle Distribution and Phosphorylation Profiles of Breast Cancer Cells: The Adipokine Receptor CAP1 Matters

BACKGROUND

Obesity and associated metabolic conditions impact adipocyte functionality with potential consequences for breast cancer risk and prognosis, but contributing mechanisms remain to be understood. The adipokine receptor adenylyl cyclase-associated protein-1 (CAP1) has been implicated in the progression of breast cancer, but results are conflicting and the underlying molecular mechanisms are still unknown. In this study, molecular and cellular effects in breast cancer cells by stimulation of adipocytes under normal or obese-like conditions, and potential involvement of CAP1, were assessed.

MATERIAL AND METHODS

Estrogen receptor (ER)-positive T47D and ER-negative MDA-MB-231 breast cancer cells were exposed to adipocyte-secretome from adipocytes placed under pressures mimicking normal and obese-like metabolic conditions. Changes in phosphorylated kinase proteins and related biological pathways were assessed by phospho-antibody array and PANTHER analysis, cell proliferation were investigated through sulforhodamine B, cell cycle distribution by flow cytometry. Functional effects of CAP1 were subsequently examined following small interfering (si)RNA-mediated knockdown.

RESULTS

Protein phosphorylations involved in important biological processes were enriched in T47D breast cancer cells in response to adipocyte secretome from obese-like compared with normal conditions. The obesity-associated adipocyte secretome further stimulated cell proliferation and a shift from cell cycle G1-phase to S- and G2/M-phase was observed. Silencing of CAP1 decreased cell proliferation in both T47D and MDA-MB-231 cells, and reduced the obesity-associated secretome-induction of phosphoproteins involved in cell proliferation pathways.

CONCLUSIONS

These results indicate that the adipocyte secretome and CAP1 are mechanistically important for the proliferation of both ER-positive and ER-negative breast cancer cells, and potential signaling mediators were identified. These studies provide biological insight into how obesity-associated factors could affect breast cancer.

Ghrelin and adipokines: An overview of their physiological role, antimicrobial activity and impact on cardiovascular conditions

The human body has many different hormones that interact with each other and with other factors such as proteins, cell receptors and metabolites. There is still a limited understanding of some of the underlying biological mechanisms of some hormones. In the past decades, science and technology have made major advancements in regard to innovation and knowledge in fields such as medicine. However, some conditions are complex and have many variables that their full picture is still unclear, even though some of these conditions have an alarming rate of incidence and serious health consequences. Conditions such as type 2 diabetes, obesity, nonalcoholic liver disease (NAFLD), cancer in its different forms and even mental conditions, such as Alzheimer's disease, are some of the most common diseases in the 21st century. These conditions are relevant not only because of their high incidence on the general population, but also because of their severity. In this chapter, we present an overview of cardiovascular (CV) diseases. According to the World Health Organization (WHO), cardiovascular diseases, such as coronary artery disease (CAD), heart attack, cardiomyopathy and heart failure (among others), are the number one cause of death worldwide. In 2016, it was estimated that 17.9 million people died from CV diseases, representing more than 30% of all global deaths. Approximately 95% of people who died from CV diseases were so-called "premature deaths" because were referenced to individuals under the age of 70 years old. In this chapter we described some of the hormones that may have an impact on CV diseases, including ghrelin, a peptide that is mostly produced in the stomach, known to induce hunger. Ghrelin is linked to an increase in body fat, i.e., adipose tissue in animals. For this reason, we also included the adipokines leptin, adiponectin and resistin. The main objectives of this chapter are to present the state of the art knowledge concerning the mechanisms of each hormone relevant to CV diseases; to compile data and results that further elucidate the relevance of these peptides for several physiological events, conditions and diseases; and to discuss the metabolic impact of each hormone. We established connections between multiple peptides and the underlying condition/disease with tools such as STRING, referring to research using databases, such as UniProt, DisGeNET and Proteomics DB. Fig. 1 shows a network that summarizes the information presented in this chapter, which serves as a visual representation.

Adipokine signatures of subcutaneous and visceral abdominal fat in normal-weight and obese women with different metabolic profiles

INTRODUCTION

Metabolic syndrome arises from abnormal adipose function accompanied by insulin resistance. As early factors reflecting/impacting lipid storage dysfunction of adipose tissues, we sought to determine adipokine levels in subcutaneous and visceral adipose tissues (SAT and VAT).

MATERIAL AND METHODS

Gene and protein expression levels of leptin, adiponectin, and resistin were analysed in SAT and VAT of normal-weight and overweight/obese women, subclassified according to insulin resistance index, triglyceride, total, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol levels into metabolically healthy and "at risk" groups.

RESULTS

Compared with normal-weight women, obese women had higher serum leptin levels (p < 0.05), as well as increased leptin gene and protein expression in VAT. Conversely, expression levels of leptin were lower in SAT of obese women, and minor in the SAT of "at risk" groups of women, compared with weight-matched healthy groups. In addition, lower adiponectin levels were detected in SAT of metabolically healthy obese women (p < 0.01), and lower in SAT and VAT (p < 0.05) of "at risk" obese women compared to healthy, obese women. Significant differences in resistin levels were only observed in obese women; resistin gene expression was higher in VAT and SAT of obese, compared to normal-weight women. However, higher gene expression was not consistent with protein expression of resistin.

CONCLUSIONS

Low adiponectin in both examined adipose tissues and inappropriate leptin expression levels in SAT appear to be important characteristics of obesity-related metabolic syndrome. Intriguingly, this adipokine dysregulation is primary seen in SAT, suggesting that endocrine dysfunction in this abdominal depot may be an early risk sign of metabolic syndrome.

Serum Adipocytokines Levels and Their Association with Insulin Sensitivity in Morbidly Obese Individuals Undergoing Bariatric Surgery

Background

Obese adipose tissue secretes a variety of adipocytokines that act as metabolic regulators with complex mechanisms. Our objective was to compare serum concentration of a panel of adipocytokines between obese and non-obese individuals and identify any distinct patterns correlating with insulin sensitivity in obesity.

Methods

We designed a cross-sectional study among obese (body mass index [BMI] ≥30 kg/m², n=62) and non-obese (BMI <25 kg/m², n=32) individuals to compare circulating levels of the adipokines, such as adiponectin and resistin in conjunction with the measurement of the levels of inflammatory cytokines including C-reactive protein (CRP), interleukin (IL)-6, IL-8, monocyte chemoattractant protein (MCP)-1, and tumor necrosis factor (TNF)-α using Luminex multiplex immunoassay with drop array technology. Correlations between circulating adipocytokine levels and those of multiple well-established markers of insulin resistance including homeostatic model assessment of insulin resistance (HOMA-IR), homeostatic model assessment of β-cell function (HOMA-β) and quantitative insulin sensitivity check index were also established.

Results

CRP, IL-8, MCP-1, and TNF-α levels were higher in obese than non-obese individuals; the CRP and IL-8 differences were statistically significant. CRP correlated significantly with markers of insulin resistance (fasting plasma insulin, HOMA-IR, and QUICKI), and adiponectin correlated with HOMA-β in obese individuals. We divided the group of obese individuals on the basis of HOMA-IR levels into insulin-resistant (IR; HOMA-IR ≥2.5) and insulin-sensitive (IS; HOMA-IR <2.5) groups; and 43 out of 62 participants were IR despite comparable BMIs. An overall proinflammatory profile was compared between IR and IS obese, though the values were higher in IR obese but the difference was not significant.

Conclusion

Obesity is associated with a general inflammatory milieu and a crosstalk between adipocytokines and insulin resistance is complex as well as multifactorial.

The Influence of Physical Activity on the Bioactive Lipids Metabolism in Obesity-Induced Muscle Insulin Resistance

High-fat diet consumption and lack of physical activity are important risk factors for metabolic disorders such as insulin resistance and cardiovascular diseases. Insulin resistance is a state of a weakened response of tissues such as skeletal muscle, adipose tissue, and liver to insulin, which causes an increase in blood glucose levels. This condition is the result of inhibition of the intracellular insulin signaling pathway. Skeletal muscle is an important insulin-sensitive tissue that accounts for about 80% of insulin-dependent glucose uptake. Although the exact mechanism by which insulin resistance is induced has not been thoroughly understood, it is known that insulin resistance is most commonly associated with obesity. Therefore, it is believed that lipids may play an important role in inducing insulin resistance. Among lipids, researchers’ attention is mainly focused on biologically active lipids: diacylglycerols (DAG) and ceramides. These lipids are able to regulate the activity of intracellular enzymes, including those involved in insulin signaling. Available data indicate that physical activity affects lipid metabolism and has a positive effect on insulin sensitivity in skeletal muscles. In this review, we have presented the current state of knowledge about the impact of physical activity on insulin resistance and metabolism of biologically active lipids.

Adipokines: New Potential Therapeutic Target for Obesity and Metabolic, Rheumatic, and Cardiovascular Diseases

Besides its role as an energy storage organ, adipose tissue can be viewed as a dynamic and complex endocrine organ, which produces and secretes several adipokines, including hormones, cytokines, extracellular matrix (ECM) proteins, and growth and vasoactive factors. A wide body of evidence showed that adipokines play a critical role in various biological and physiological functions, among which feeding modulation, inflammatory and immune function, glucose and lipid metabolism, and blood pressure control. The aim of this review is to summarize the effects of several adipokines, including leptin, diponectin, resistin, chemerin, lipocalin-2 (LCN2), vaspin, omentin, follistatin-like 1 (FSTL1), secreted protein acidic and rich in cysteine (SPARC), secreted frizzled-related protein 5 (SFRP5), C1q/TNF-related proteins (CTRPs), family with sequence similarity to 19 member A5 (FAM19A5), wingless-type inducible signaling pathway protein-1 (WISP1), progranulin (PGRN), nesfatin-1 (nesfatin), visfatin/PBEF/NAMPT, apelin, retinol binding protein 4 (RPB4), and plasminogen activator inhibitor-1 (PAI-1) in the regulation of insulin resistance and vascular function, as well as many aspects of inflammation and immunity and their potential role in managing obesity-associated diseases, including metabolic, osteoarticular, and cardiovascular diseases.

Metabolic status in children and its transitions during childhood and adolescence-the IDEFICS/I.Family study

BACKGROUND

This study aimed to investigate metabolic status in children and its transitions into adolescence.

METHODS

The analysis was based on 6768 children who participated in the European IDEFICS/I.Family cohort (T0 2007/2008, T1 2009/2010 and/or T3 2013/2014; mean ages: 6.6, 8.4 and 12.0 years, respectively) and provided at least two measurements of waist circumference, blood pressure, blood glucose and lipids over time. Latent transition analysis was used to identify groups with similar metabolic status and to estimate transition probabilities.

RESULTS

The best-fitting model identified five latent groups: (i) metabolically healthy (61.5%; probability for group membership at T0); (ii) abdominal obesity (15.9%); (iii) hypertension (7.0%); (iv) dyslipidaemia (9.0%); and (v) several metabolic syndrome (MetS) components (6.6%). The probability of metabolically healthy children at T0 remaining healthy at T1 was 86.6%; when transitioning from T1 to T3, it was 90.1%. Metabolically healthy children further had a 6.7% probability of developing abdominal obesity at T1. Children with abdominal obesity at T0 had an 18.5% probability of developing several metabolic syndrome (MetS) components at T1. The subgroup with dyslipidaemia at T0 had the highest chances of becoming metabolically healthy at T1 (32.4%) or at T3 (35.1%). Only a minor proportion of children showing several MetS components at T0 were classified as healthy at follow-up; 99.8% and 88.3% remained in the group with several disorders at T1 and T3, respectively.

CONCLUSIONS

Our study identified five distinct metabolic statuses in children and adolescents. Although lipid disturbances seem to be quite reversible, abdominal obesity is likely to be followed by further metabolic disturbances.

Intrauterine growth restriction: the controversial role of perinatal adipocytokines in the prediction of metabolic adult disease

"Prenatal/fetal programming," implying structural/functional disorders of developing tissues/organs, consequent to an adverse intrauterine environment leading to asymmetric intrauterine growth restriction (IUGR), predisposes to metabolic syndrome and noncommunicable diseases in adulthood, in the framework of the "Developmental Origins of Health and Disease" (DOHaD) concept. DOHaD consequences are associated with adipose tissue, particularly the visceral one, occurring in relative abundance in IUGR infants. Adipose tissue secretes numerous hormones, collectively called adipocytokines, as leptin, adiponectin, ghrelin, resistin, apelin, visfatin, omentin, vaspin, preadipocyte factor-1 (Pref-1), fatty acid-binding protein-4, lipocalin-2, and others, implicated in fetal growth, body metabolism, energy homeostasis, and insulin resistance. Early identification of adipocytokines as biomarkers predicting later metabolic disorders/diseases in IUGR individuals, enabling relevant protective interventions, would be of utmost importance. Current data do not support this perspective, due to controversial results in the literature, with the eventual exception of visfatin and possibly Pref-1.

Study of changes of obesity-related inflammatory cytokines after laparoscopic sleeve gastrectomy

BACKGROUND

Chronic inflammation in adipose tissue may play a substantial role in the pathogenesis of obesity-related metabolic disorders. The present study aims to evaluate the changes in adipocytokines, bile acids, fibroblast growth factor 19 (FGF-19) and pro-inflammatory cytokines 6 months after laparoscopic sleeve gastrectomy (LSG).

METHODS

This prospective study included 75 obese patients with body mass index >35 kg/m² who underwent LSG. All patients were recruited preoperatively and followed up post-operatively at 6 months, with laboratory assessment of their cytokines including adiponectin, leptin, resistin, bile acid, interleukin (IL)-6, IL-8, tumour necrosis factor-α, monocyte chemotactic protein-1, high-sensitivity C-reactive protein, plasminogen activator inhibitor-1, serum amyloid-A and FGF-19.

RESULTS

There were statistically highly significant changes regarding anthropometric parameters (weight, body mass index and waist-to-hip ratio), blood glucose and lipid profile as well as liver enzymes at 6 months post-sleeve gastrectomy. The present study showed that the levels of serum adiponectin and FGF-19 significantly increased at 6 months of follow-up after surgery (P < 0.001), while the levels of serum leptin, resistin, high-sensitivity C-reactive protein, plasminogen activator inhibitor-1 and serum amyloid-A significantly decreased at 6 months of follow-up after surgery (P < 0.001). There were no significant differences regarding serum bile acid, IL-6, IL-8, tumour necrosis factor-α and monocyte chemotactic protein-1.

CONCLUSION

Weight loss after LSG is associated with significant improvement of the adipokine levels towards anti-diabetic and anti-inflammatory profiles. Future studies should use a larger sample size and longer follow-up periods.

Serum and vitreous resistin levels in patıents with proliferative diabetic retinopathy

AIM

The aim of the study was to investigate the serum and vitreous levels of resistin in patients with the proliferative diabetic retinopathy (PDR) and to compare those with age-matched control subjects.

METHODS

The study included 45 eyes with PDR (group 1) and a control group of 22 (group 2). All eyes underwent vitrectomy surgery. The lipid profile, fasting blood glucose (FBG), HbA1c and resistin levels were investigated in blood samples of all subjects. Complete ophthalmological examinations were evaluated. Vitreous samples were collected from both groups during vitrectomy surgery and resistin levels were investigated in those samples. The results were evaluated using SPSS 9.0 software.

RESULTS

The demographic characteristics of the diabetic group and the control group were similar (p > 0.05). There was no significant difference between the groups in respect of mean visual acuity (VA), body mass index (BMI) values, or lipid profiles (p ˃ 0.05). There was no measurable value of resistin in the vitreous samples of all the eyes. The mean blood resistin level was 367 ng/ml in the control group and 387 ng/ml in the study group and the difference was not statistically significant (p > 0.05).

CONCLUSIONS

In the light of the findings of this study, it can be assumed that resistin did not pass through the vitreous at measurable levels. However, the serum resistin levels of the diabetic patients were higher than those of the control group although not statistically significant. Therefore, it can be considered that resistin does not play a major role in retinal neovascularization.

Rice Bran Reduces Weight Gain and Modulates Lipid Metabolism in Rats with High-Energy-Diet-Induced Obesity

Obesity has become an epidemic worldwide. It is a complex metabolic disorder associated with many serious complications and high morbidity. Rice bran is a nutrient-dense by product of the rice milling process. Asia has the world’s highest rice production (90% of the world’s rice production); therefore, rice bran is inexpensive in Asian countries. Moreover, the high nutritional value of the rice bran suggests its potential as a food supplement promoting health improvements, such as enhancing brain function, lowering blood pressure, and regulating pancreatic secretion. The present study evaluated the anti-obesity effect of rice bran in rats with high-energy diet (HED)-induced obesity. Male Sprague–Dawley rats were randomly divided into one of five diet groups (n = 10 per group) and fed the following for eight weeks: Normal diet with vehicle treatment, HED with vehicle, rice bran-0.5X (RB-0.5X) (2% wt/wt rice bran), RB-1.0X (4% wt/wt rice bran), and RB-2.0X (8% wt/wt rice bran). Rice bran (RB-1.0X and RB-2.0X groups) markedly reduced obesity, including body weight and adipocyte size. In addition, treating rats with HED-induced obesity using rice bran significantly reduced the serum uric acid and glucose as well as the liver triglyceride (TG) and total cholesterol (TC). Furthermore, administration of an HED to obese rats significantly affected hepatic lipid homeostasis by increasing phosphotidylcholine (PC; 18:2/22:6), diacylglycerol (DG; 18:2/16:0), DG (18:2/18:1), DG (18:1/16:0), cholesteryl ester (CE; 20:5), CE (28:2), TG (18:0/16:0/18:3), and glycerol-1-2-hexadecanoate 3-octadecanoate. However, the rice bran treatment demonstrated an anti-adiposity effect by partially reducing the HED-induced DG (18:2/18:1) and TG (18:0/16:0/18:3) increases in obese rats. In conclusion, rice bran could act as an anti-obesity supplement in rats, as demonstrated by partially reducing the HED-induced DG and TG increases in obese rats, and thus limit the metabolic diseases associated with obesity and the accumulation of body fat and hepatic lipids in rats.

Engineered skeletal muscles for disease modeling and drug discovery

Skeletal muscle is the largest organ of human body with several important roles in everyday movement and metabolic homeostasis. The limited ability of small animal models of muscle disease to accurately predict drug efficacy and toxicity in humans has prompted the development in vitro models of human skeletal muscle that fatefully recapitulate cell and tissue level functions and drug responses. We first review methods for development of three-dimensional engineered muscle tissues and organ-on-a-chip microphysiological systems and discuss their potential utility in drug discovery research and development of new regenerative therapies. Furthermore, we describe strategies to increase the functional maturation of engineered muscle, and motivate the importance of incorporating multiple tissue types on the same chip to model organ cross-talk and generate more predictive drug development platforms. Finally, we review the ability of available in vitro systems to model diseases such as type II diabetes, Duchenne muscular dystrophy, Pompe disease, and dysferlinopathy.

Interleukin-15 inhibits adipogenic differentiation of cattle bone marrow-derived mesenchymal stem cells via regulating the crosstalk between signal transducer and activator of transcription 5A and Akt signalling

Interleukin (IL)-15 is an important regulator of adipogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). This study was designed to clarify the underlying mechanism. BMSCs were obtained from Nanyang cattle and stimulated to differentiate into adipocytes using standard differentiation medium. Oil Red O staining was used to assess lipid accumulation. Western blotting and quantitative real-time polymerase chain reaction were used to assess protein and mRNA levels, respectively. Recombinant IL-15 treatment inhibited adipogenic differentiation of cattle BMSCs in vitro, as evidenced by reduced induction of the adipocyte markers, peroxisome proliferator activated receptor γ (PPARγ) and fatty acid binding protein 4 (αP2). IL-15 not only activated the signal transducers and activators of transcription (STAT) pathway, but also attenuated the activation of phosphoinositide 3-kinase (PI3K)/Akt signalling by insulin, a major inducer of adipocyte differentiation. In the presence of the STAT-specific inhibitor, 573108, the inhibitory effect of IL-15 on PPARγ and αP2 expression was abolished. Meanwhile, IL-15-attenuated PI3K/Akt signalling was also rescued. IL-15 may regulate adipogenic differentiation of BMSCs by inhibiting PI3K/Akt activation via the STAT5A pathway. Our data raise the possibility of using IL-15 in the therapy of obesity-related diseases, such as cardiovascular diseases and type 2 diabetes.

Inflammatory markers in children and adolescents with type 2 diabetes mellitus

This review examines the potential relationship between serum inflammation markers and type 2 diabetes mellitus (T2DM). Inflammation markers have been proposed as prognostic markers for the development of T2DM and its complications. Furthermore, modulation of the inflammatory process may offer future treatment strategies for T2DM. This review focuses on children and adolescents because there is usually little, if any, complications associated with other disease processes, use of medications, or active tobacco smoking. Furthermore, β-cell failure in young age cannot be solely explained by aging and exhaustion of β-cells due to insulin resistance. Pediatric studies have demonstrated that pro-inflammatory cytokines TNF-α, IL-6, IL-1β, IFNγ, PEDF, and fetuin A were increased in insulin resistance, while the anti-inflammatory cytokines adiponectin and omentin were decreased. Furthermore, TNF-α, fetuin A, FGF-21 were altered in obese children with T2DM suggesting a direct involvement in β-cell failure. Future studies focusing on children and adolescents may facilitate our understanding of T2DM as an inflammatory disease process.

An update on metabolic syndrome: Metabolic risk markers and adipokines in the development of metabolic syndrome

Metabolic syndrome is a collection of physiological and biochemical abnormalities about 20-25% of adult population in developing countries is suffering from metabolic syndrome. Previous research demonstrated that adipose tissue plays an important role in energy regulation via endocrine, paracrine and autocrine signals as results of obesity due to accumulation of adipose tissue to excess that by time affects negatively both physical and psychological health and well being, it has been found that adipose tissues produces a variety of factors known as "adipokines" which play a key role in the development and progression of the disease and also hypothesized that adipokines are a possible link between obesity and the other risk components of the Metabolic syndrome. Many of the adipokines exert multiple actions in a variety of cellular processes leading to a complex array of abnormal characteristic of Metabolic syndrome. Abnormal production of these adipokines by expanded visceral fat during Adiposity contributes to a pro-inflammatory state. Increasing evidence suggests that aberrant production/release of adipokine from adipocyte i.e. adiponectin, leptin and resistin etc, may contribute to the health problems associated with Adiposity such as dyslipidemia, insulin resistance and atherosclerosis. This study conclusively have shown a significant role of adipokines secreted by adipose tissue and various metabolic risk markers play a important role in the development of Metabolic syndrome.