Insulin resistance and type 2 diabetes are not related to resistin expression in human fat cells or skeletal muscle

The Interplay of Adipokines and Pancreatic Beta Cells in Metabolic Regulation and Diabetes

The interplay between adipokines and pancreatic beta cells, often referred to as the adipo-insular axis, plays a crucial role in regulating metabolic homeostasis. Adipokines are signaling molecules secreted by adipocytes that have profound effects on several physiological processes. Adipokines such as adiponectin, leptin, resistin, and visfatin influence the function of pancreatic beta cells. The reciprocal communication between adipocytes and beta cells is remarkable. Insulin secreted by beta cells affects adipose tissue metabolism, influencing lipid storage and lipolysis. Conversely, adipokines released from adipocytes can influence beta cell function and survival. Chronic obesity and insulin resistance can lead to the release of excess fatty acids and inflammatory molecules from the adipose tissue, contributing to beta cell dysfunction and apoptosis, which are key factors in developing type 2 diabetes. Understanding the complex interplay of the adipo-insular axis provides insights into the mechanisms underlying metabolic regulation and pathogenesis of metabolic disorders. By elucidating the molecular mediators involved in this interaction, new therapeutic targets and strategies may emerge to reduce the risk and progression of diseases, such as type 2 diabetes and its associated complications. This review summarizes the interactions between adipokines and pancreatic beta cells, and their roles in the pathogenesis of diabetes and metabolic diseases.

Pancreatic Islets as a Target of Adipokines

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

Inflammation as a link between periodontal disease and obesity

Nutrition plays a critical role in the homeostatic balance, maintenance of health, and longevity. There is a close link between inflammatory diseases and nutritional health. Obesity is a severe pathological process with grave implications on several organ systems and disease processes, including type 2 diabetes, cardiovascular disease, osteoarthritis, and rheumatoid arthritis. The impact of obesity on periodontal inflammation has not been fully understood; the association between nutritional balance and periodontal inflammation is much less explored. This review is focused on the potential mechanistic links between periodontal diseases and obesity and common inflammatory activity pathways that can be pharmacologically targeted.

FIZZ2 as a Biomarker for Acute Exacerbation of Chronic Obstructive Pulmonary Disease

PURPOSE

Found in inflammatory zone 2 (FIZZ2) is associated with lung inflammation. The aim of the study was to investigate the expression and utility of FIZZ2 as a marker for chronic obstructive pulmonary disease (COPD).

METHODS

Immunohistochemistry was used to detect the expression of FIZZ2 in COPD. The serum concentration of FIZZ2 was measured by enzyme-linked immunosorbent assay and the episodes of acute exacerbations of COPD (AECOPD) in the following year were recorded.

RESULTS

FIZZ2 expression was elevated in bronchial epithelial cells (0.217 ± 0.021 vs 0.099 ± 0.010, p < 0.0001) and negatively correlated with the pulmonary function (FEV1/FVC%) (p = 0.0149) and positively correlated with the smoking index (p = 0.0241). Serum level of FIZZ2 in COPD were significantly higher than that in healthy controls (561.6 ± 70.71 vs 52.24 ± 20.52 pg/ml, p < 0.0001) and increased with the COPD severity. Serum levels of FIZZ2 negatively correlated with the pulmonary function [Forced Vital Capacity (FVC), Forced Expiratory Volume (FEV1), FEV1%, FEV1/FVC) (r =  - 0.3086, - 0.3529, - 0.3343, and - 0.2676, respectively, p = 0.0003, p < 0.0001, p < 0.0001, p = 0.0014). The expression of human serum FIZZ2 was positively correlated with the smoking index (r = 0.2749, p = 0.0015). There was a positive correlation between the FIZZ2 concentration and the frequency of AECOPD episodes in the following year (r = 0.7291, p < 0.0001).

CONCLUSION

FIZZ2 expression was elevated in patients with COPD and its serum concentration might be a potential biomarker for AECOPD.

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.

The effects of physical activity on adipokines in individuals with overweight/obesity across the lifespan: A narrative review

This narrative review summarizes current knowledge on the effects of physical activity (PA) on adipokine levels in individuals with overweight and obesity. Approximately 90 investigations including randomized control, cross-sectional and longitudinal studies that reported on the effects of a single session of PA (acute) or long-term PA (chronic) on adipokine levels in individuals with overweight/obesity were reviewed. The findings support the notion that there is consensus on the benefits of chronic exercise training-regardless of the mode (resistance vs. aerobic), intensity and cohort (healthy vs. diabetes)-on adipokine levels (such as tumour necrosis factor-alpha, interleukin-6, adiponectin, visfatin, omentin-1 and leptin). However, several confounding factors (frequency, intensity, time and type of exercise) can alter the magnitude of the effects of an acute exercise session. Available evidence suggests that PA, as a part of routine lifestyle behaviour, improves obesity complications by modulating adipokine levels. However, additional research is needed to help identify the most effective interventions to elicit the most beneficial changes in adipokine levels in individuals with overweight/obesity.

Transcriptomic signature of fasting in human adipose tissue

Little is known about gene regulation by fasting in human adipose tissue. Accordingly, the objective of this study was to investigate the effects of fasting on adipose tissue gene expression in humans. To that end, subcutaneous adipose tissue biopsies were collected from 11 volunteers 2 and 26 h after consumption of a standardized meal. For comparison, epididymal adipose tissue was collected from C57Bl/6J mice in the ab libitum-fed state and after a 16 h fast. The timing of sampling adipose tissue roughly corresponds with the near depletion of liver glycogen. Transcriptome analysis was carried out using Affymetrix microarrays. We found that, 1) fasting downregulated numerous metabolic pathways in human adipose tissue, including triglyceride and fatty acid synthesis, glycolysis and glycogen synthesis, TCA cycle, oxidative phosphorylation, mitochondrial translation, and insulin signaling; 2) fasting downregulated genes involved in proteasomal degradation in human adipose tissue; 3) fasting had much less pronounced effects on the adipose tissue transcriptome in humans than mice; 4) although major overlap in fasting-induced gene regulation was observed between human and mouse adipose tissue, many genes were differentially regulated in the two species, including genes involved in insulin signaling (PRKAG2, PFKFB3), PPAR signaling (PPARG, ACSL1, HMGCS2, SLC22A5, ACOT1), glycogen metabolism (PCK1, PYGB), and lipid droplets (PLIN1, PNPLA2, CIDEA, CIDEC). In conclusion, although numerous genes and pathways are regulated similarly by fasting in human and mouse adipose tissue, many genes show very distinct responses to fasting in humans and mice. Our data provide a useful resource to study adipose tissue function during fasting.

Resistin family proteins in pulmonary diseases

The family of resistin-like molecules (RELMs) consists of four members in rodents (RELMα/FIZZ1/HIMF, RELMβ/FIZZ2, Resistin/FIZZ3, and RELMγ/FIZZ4) and two members in humans (Resistin and RELMβ), all of which exhibit inflammation-regulating, chemokine, and growth factor properties. The importance of these cytokines in many aspects of physiology and pathophysiology, especially in cardiothoracic diseases, is rapidly evolving in the literature. In this review article, we attempt to summarize the contribution of RELM signaling to the initiation and progression of lung diseases, such as pulmonary hypertension, asthma/allergic airway inflammation, chronic obstructive pulmonary disease, fibrosis, cancers, infection, and other acute lung injuries. The potential of RELMs to be used as biomarkers or risk predictors of these diseases also will be discussed. Better understanding of RELM signaling in the pathogenesis of pulmonary diseases may offer novel targets or approaches for the development of therapeutics to treat or prevent a variety of inflammation, tissue remodeling, and fibrosis-related disorders in respiratory, cardiovascular, and other systems.

Resistin concentrations in serum and stifle synovial fluid from normal and cruciate deficient dogs with osteoarthritis

OBJECTIVE

To compare synovial fluid (SF) resistin concentrations in healthy dogs to dogs with osteoarthritis (OA) secondary to cranial cruciate ligament (CrCL) injury and to correlate resistin concentrations with body condition score (BCS) and evaluate resistin release from peripheral blood mononuclear cells (PBMC) and adipocytes.

STUDY DESIGN

Controlled, prospective, clinical study ANIMALS: Thirty-nine client-owned dogs, 13 healthy and 26 with secondary OA, were enrolled. Blood was collected from six healthy purpose-bred dogs for PBMC culture. An additional six mixed-breed dogs were used for adipocyte collection and culture.

METHODS

Resistin concentrations were measured with a canine-specific enzyme-linked immunoabsorbent assay. Resistin was compared between healthy SF and OA SF with Student's t test. Correlation of resistin concentrations to BCS was performed. Peripheral blood mononuclear cells and adipocytes were cultured under three conditions: negative control, lipopolysaccharide, and concanavalin A (Con A). A linear mixed model was used to determine differences in resistin concentrations among treatments.

RESULTS

Resistin concentrations in OA SF were comparable to healthy SF. Neither serum nor SF resistin was correlated with BCS. Cultured PBMC stimulated with Con A released resistin, while adipocytes did not.

CONCLUSION

Neither serum nor SF resistin were altered in dogs with OA secondary to CrCL insufficiency. In addition, resistin was not correlated with canine body fat and did not appear to function as adipocytokine in the dog.

CLINICAL SIGNIFICANCE

Resistin may not be involved in the pathogenesis of OA. However, resistin may be important in inflammation because it is released from inflammatory cells.

Adipokines as key players in β cell function and failure

The growing prevalence of obesity and its related metabolic diseases, mainly Type 2 diabetes (T2D), has increased the interest in adipose tissue (AT) and its role as a principal metabolic orchestrator. Two decades of research have now shown that ATs act as an endocrine organ, secreting soluble factors termed adipocytokines or adipokines. These adipokines play crucial roles in whole-body metabolism with different mechanisms of action largely dependent on the tissue or cell type they are acting on. The pancreatic β cell, a key regulator of glucose metabolism due to its ability to produce and secrete insulin, has been identified as a target for several adipokines. This review will focus on how adipokines affect pancreatic β cell function and their impact on pancreatic β cell survival in disease contexts such as diabetes. Initially, the "classic" adipokines will be discussed, followed by novel secreted adipocyte-specific factors that show therapeutic promise in regulating the adipose-pancreatic β cell axis.

In silico design of peptides as potential ligands to resistin

Resistin is a hormone of biological interest due to its connection with several diseases of worldwide concern. This work aims to design a series of cyclic peptides as "lead compounds" to identify potential ligands to resistin. To this end, we propose an approach based on a peptide design algorithm plus a two-stage selection which accounts for selectivity, one of the most forgotten steps in the design of ligands. Following this approach, we have been able to identify several peptides as strong candidates for the design of elements of bio-recognition. Those peptides present low scoring binding energy to albumin, good water solubility, stability in water at 300 K, and high scoring binding energy to resistin. Among those peptides, two were chosen, to perform a more rigorous calculation of binding free energy based on the Alchemical Absolute Binding Free Energy method. We were able to establish a methodological route for the development of strong candidates for the design of ligands to resistin. Graphical Abstract Combined MD + MC + AABFE approach to design and screening of high-affinity binders to resistin.

Cardiovascular responses produced by resistin injected into paraventricular nucleus mediated by the glutamatergic and CRFergic transmissions within rostral ventrolateral medulla

OBJECTIVES

Resistin, as a 12.5 kDa cysteine-rich polypeptide, is expressed in hypothalamus and regulates sympathetic nerve activity. It is associated with obesity, metabolic syndrome and cardiovascular diseases. In this study, we investigated the neural pathway of cardiovascular responses induced by injection of resistin into paraventricular nucleus (PVN) with rostral ventrolateral medulla (RVLM).

MATERIALS AND METHODS

Adult male rats were anesthetized with urethane (1.4 g/kg intraperitoneally). Resistin (3 µg/1 µl/rat) was first injected into PVN, and the glutamatergic, corticotrophin-releasing factor (CRF)-ergic and angiotensinogenic transmission was inhibited by injecting of their antagonist in RVLM. Arterial pressure (AP) and heart rate (HR) were monitored before and after the injection.

RESULTS

The results showed that resistin injection into PVN significantly increased AP and HR compared to control group and prior to its injection (P<0.05). Injection of AP5 ((2R)-amino-5-phosphonovaleric acid; (2R)-amino-5-phosphonopentanoate) (50 nM/rat), losartan (10 nM/rat) and astressin (50 nM/rat) into RVLM reduced cardiovascular responses produced by injected resistin into PVN. Injection of AP5+losartan or astressin+losartan or astressin+AP5 into RVLM could significantly reduce cardiovascular responses produced by resistin compared to before injection (P<0.05). Furthermore, the depressor responses generated by AP5+losartan injected into RVLM were significantly stronger than the depressor responses generated by AP5+astressin and/or astressin+losartan injected into RVLM (P<0.05).

CONCLUSION

It can be concluded that glutamatergic and CRFergic transmissions have crucial contribution to cardiovascular responses produced by resistin. The results provided new and potentially important insight regarding neural transmission when the plasma level of resistin increases; this reveals the role of resistin in cardiovascular responses such as metabolic syndrome and hypertension.

AKSAKAL B. The effect of isotretinoin on insulin resistance and adipocytokine levels in acne vulgaris patients

Background/aim

Recent data draw attention to the effect of body composition, insulin resistance, and adipocytokines to acne vulgaris (AV) development. The aim of this study was to assess the association of AV with insulin resistance and adipocytokine levels and to evaluate the effect of isotretinoin on insulin resistance and adipocytokine levels.

Materials and methods

In 29 AV patients and 29 healthy volunteers, body mass index (BMI) and body fat mass (BFM), lipid, adiponectin, leptin, resistin, retinol binding protein-4 (RBP4), and insulin levels were measured and insulin resistance was assessed by HOMA-IR index in serum samples taken twice from patients before and after isotretinoin treatment.

Results

In AV patients, pretreatment HOMA-IR and adipocytokine levels were not found to correlate with disease severity. With five months of isotretinoin treatment, higher HOMA-IR values ​​were found (P = 0.028). Isotretinoin therapy maintained lower mean resistin levels (P = 0.016), higher mean RBP4 levels (P = 0.040), but not affected the mean adiponectin and leptin levels (P = 0.113, P = 0.125, respectively).

Conclusions

All data suggests that five months of isotretinoin therapy in AV patients causes insulin resistance and the increase in insulin resistance is not dependent on age, BMI, BFM, and lipid levels of these patients.

Adipokines Regulate the Expression of Tumor-Relevant MicroRNAs

BACKGROUND

Increasing prevalence of obesity requires the investigation of respective comorbidities, including tumor diseases like colorectal, renal, post-menopausal breast, prostate cancer, and leukemia. To date, molecular mechanisms of the malignant transformation of these peripheral tissues induced by obesity remain unclear. Adipose tissue secretes factors with hormone-like functions, the adipokines, and is therefore categorized as an endocrine organ. Current research demonstrates the ability of adipose tissue to alter DNA methylation and gene expression in peripheral tissues, probably affecting microRNA (miR) expression.

METHODS

Literature was analyzed for adipokine-regulated miRs. Many of these adipokine upregulated or downregulated miRs exert either oncogenic or anti-tumoral potential.

RESULTS

The three selected and analyzed adipokines, adiponectin, leptin, and resistin, induce more strongly oncogenic miRs and simultaneously reduce anti-tumoral miRs than vice versa. This effect is not only true for the pure number of regulated miRs, it is also the case by consideration of the abundance of the respective miR expression based on actual data sets derived from next-generation sequencing.

CONCLUSION

The link of obesity and cancer is analyzed under the aspect of adipokine-regulated miRs. At the same time the impact of miR abundance is considered as a regulatory variable. This context offers new strategies for tumor therapy and diagnostics.

Visfatin and resistin in gonadotroph cells: expression, regulation of LH secretion and signalling pathways

Visfatin and resistin appear to interfere with reproduction in the gonads, but their potential action at the hypothalamic-pituitary level is not yet known. The aim of the present study was to investigate the mRNA and protein expression of these adipokines in murine gonadotroph cells and to analyse the effects of different concentrations of recombinant mouse visfatin and resistin (0.01, 0.1, 1 and 10ngmL^-1) on LH secretion and signalling pathways in LβT2 cells and/or in primary female mouse pituitary cells. Both visfatin and resistin mRNA and protein were found in vivo in gonadotroph cells. In contrast with resistin, the primary tissue source of visfatin in the mouse was the skeletal muscle, and not adipose tissue. Visfatin and resistin both decreased LH secretion from LβT2 cells after 24h exposure of cells (P<0.03). These results were confirmed for resistin in primary cell culture (P<0.05). Both visfatin (1ngmL^-1) and resistin (1ngmL^-1) increased AMP-activated protein kinase α phosphorylation in LβT2 cells after 5 or 10min treatment, up to 60min (P<0.04). Extracellular signal-regulated kinase 1/2 phosphorylation was transiently increased only after 5min resistin (1ngmL^-1) treatment (P<0.01). In conclusion, visfatin and resistin are expressed in gonadotroph cells and they may affect mouse female fertility by regulating LH secretion at the level of the pituitary.

Here, there and everywhere: Resistin-like molecules in infection, inflammation, and metabolic disorders

The Resistin-Like Molecules (RELM) α, β, and γ and their namesake, resistin, share structural and sequence homology but exhibit significant diversity in expression and function within their mammalian host. RELM proteins are expressed in a wide range of diseases, such as: microbial infections (eg. bacterial and helminth), inflammatory diseases (eg. asthma, fibrosis) and metabolic disorders (eg. diabetes). While the expression pattern and molecular regulation of RELM proteins are well characterized, much controversy remains over their proposed functions, with evidence of host-protective and pathogenic roles. Moreover, the receptors for RELM proteins are unclear, although three receptors for resistin, decorin, adenylyl cyclase-associated protein 1 (CAP1), and Toll-like Receptor 4 (TLR4) have recently been proposed. In this review, we will first summarize the molecular regulation of the RELM gene family, including transcription regulation and tissue expression in humans and mouse disease models. Second, we will outline the function and receptor-mediated signaling associated with RELM proteins. Finally, we will discuss recent studies suggesting that, despite early misconceptions that these proteins are pathogenic, RELM proteins have a more nuanced and potentially beneficial role for the host in certain disease settings.

Association between Resistin Gene Polymorphisms and Atopic Dermatitis

Atopic dermatitis (AD) is a chronic, relapsing, and inflammatory skin disorder. It is characterized by an inappropriate skin barrier function, allergen sensitization, and recurrent skin infections. Resistin is an adipokine expressed mainly in macrophages and monocytes; it has a role in the inflammatory process and is associated with multiple inflammatory human diseases; however, only few studies linked resistin to atopic dermatitis. This study tested the association between G>A (rs3745367) and C>T (rs3219177) single nucleotide polymorphisms (SNPs) of the RETN gene with atopic dermatitis. In addition, it explored the relationship between serum resistin protein and atopic dermatitis. To achieve objectives of this study, 162 atopic dermatitis patients and 161 healthy participants were recruited in the study. A significant association was detected between rs3745367 and atopic dermatitis with age and gender specificity (p < 0.05), while no significant association between rs3219177 and atopic dermatitis was found (p > 0.05). For the serum resistin levels, a significant decrease was indicated in atopic dermatitis patients compared to healthy subjects (p < 0.05). In conclusion, rs3745367 may play a gender and age-specific role in atopic dermatitis. In addition, the significant decrease in the resistin protein level confirmed this association.

Down-regulated resistin level in consequence of decreased neutrophil counts in untreated Grave's disease

Resistin, belongs to cysteine-rich secretory protein, is mainly produced by circulating leukocytes, such as neutrophils monocytes and macrophages in humans. To date, few but controversial studies have reported about resistin concentrations in hyperthyroid patients, especially in Graves' disease (GD). We undertaked a controlled, prospective study to explore the serum resistin concentration in GD patients before and after -MMI treatment. In addition, we also investigated the main influencing factor on serum resistin level and discuessed the potential role of serum resistin plays in GD patients. 39 untreated GD (uGD) patients, including 8 males and 31 females, were enrolled in our investigation. All of these patients were prescribed with MMI treatment, in addition to 25 healthy controls. Anthropometric parameters and hormone assessment were measured. Enzyme-linked immunosorbent assay was used to detect serum resistin concentration in different stages of GD patients. Furthermore, neutrophil cell line NB4 with or without T3 treatment to detect the effect of thyroid hormones on resistin expression. The serum resistin level and neutrophil counts in untreated GD patients were significantly declined. And all of these parameters were recovered to normal after MMI treatment in ethyroid GD (eGD) and TRAb-negative conversion (nGD) patients. Resistin concentration exhibited a negative correlation with FT3 and FT4, but a positive correlation with absolute number of neutrophiles in uGD patients, whereas did not correlate with thyroid autoimmune antibodies and BMI. Neutrophile cell line, NB4, produced decreased expression of resistin when stimulated with T3. Our study showed a decrease of serum resistin level in GD patients and we suggested that the serum resistin might primarily secreted from circulating neutrophils and down-regulated by excessive thyroid hormones in GD patients.

Serum levels of leptin, adiponectin and resistin in patients with ankylosing spondylitis: A systematic review and meta-analysis

OBJECTIVES

Various studies have researched the serum levels of leptin, adiponectin and resistin in patients with ankylosing spondylitis (AS), but the results were inconclusive. The purpose of this study was to systematically evaluate the correlations between serum levels of these adipokines and AS.

METHODS

Electronic databases were retrieved to search relevant publications. Pooled standard mean difference (SMD) with 95% confidence interval (CI) was calculated by the random-effect model. Cochrane Q test and I² statistic were used to test heterogeneity. Subgroup analysis and meta-regression were applied to assess possible sources of heterogeneity.

RESULTS

A total of sixteen articles were included. Meta-analysis results indicated no statistical differences between AS patients and normal controls in serum leptin and adiponectin levels (leptin, SMD=0.829, 95% CI=-0.116 to 1.774, p=0.085; adiponectin, SMD=0.460, 95% CI=-0.004 to 0.924, p=0.052). However, AS patients had higher serum resistin levels than controls (SMD=1.413, 95% CI=0.294 to 2.531, p=0.013). Subgroup analyses suggested that Asian and African AS patients as well as patients aged <40years had higher serum leptin and resistin levels when compared to controls. Serum adiponectin levels were higher in AS patients compared to controls in subgroup of age ≥40, and serum resistin levels in subgroup of BMI ≥25. Measurement method was a source of heterogeneity for resistin. Publication bias was not observed and the robustness of study results was confirmed by sensitivity analysis.

CONCLUSION

Serum resistin, but not leptin or adiponectin levels may be closely associated with the development of AS.

Resistin Gene Expression is Downregulated in CD4(+) T Helper Lymphocytes and CD14(+) Monocytes in Rheumatoid Arthritis Responding to TNF-α Inhibition

Rheumatoid arthritis (RA) is caused by complex interactions between immune cells and sustained by Th1 response cytokines. Resistin [resistance to insulin; (RETN)] is an inflammatory cytokine, first discovered in murine adipocytes. In man, RETN is mainly secreted by monocytes. The distinct role of RETN in the immune reaction is uncertain; however, RETN has pro-inflammatory, pro-fibrotic and possibly tolerogenic properties. The aim was to assess the reaction of RETN gene expression to TNF-α inhibition (I) in pathogenetic immune cell subsets in RA, in the context of Th1, inflammatory and regulatory cytokine gene expressions. Accordingly, we measured RETN, IFN-γ, TNF-β, IL-1β, TNF-α, TGF-β and IL-10 gene expressions in CD14(+) monocytes, CD4(+) T helper (Th) lymphocytes (ly), CD8(+) T cytotoxic (Tc) ly and CD19(+) B ly in active RA before and 3 months after start of TNF-αI. Leucocyte subsets were separated by specific monoclonal antibody-covered beads, RNA extracted and levels of RETN, Th1 response, inflammatory and regulatory cytokine mRNAs measured by quantitative reverse transcription-polymerase chain reaction technique. We found that TNF-αI caused a significant downregulation of RETN gene expression in CD14(+) monocytes and CD4(+) Th ly and was unchanged in CD8(+) Tc ly and CD19(+) B ly. Both in active RA and during TNF-αI, RETN mRNA levels were significantly higher in CD14(+) monocytes than in all other examined cell types. In monocytes, fold change in RETN and TGF-β gene expressions upon TNF-αI correlated significantly. Our findings indicate that RETN has pro-inflammatory as well as proresolving roles in active RA.

Adipose tissue in control of metabolism

Adipose tissue plays a central role in regulating whole-body energy and glucose homeostasis through its subtle functions at both organ and systemic levels. On one hand, adipose tissue stores energy in the form of lipid and controls the lipid mobilization and distribution in the body. On the other hand, adipose tissue acts as an endocrine organ and produces numerous bioactive factors such as adipokines that communicate with other organs and modulate a range of metabolic pathways. Moreover, brown and beige adipose tissue burn lipid by dissipating energy in the form of heat to maintain euthermia, and have been considered as a new way to counteract obesity. Therefore, adipose tissue dysfunction plays a prominent role in the development of obesity and its related disorders such as insulin resistance, cardiovascular disease, diabetes, depression and cancer. In this review, we will summarize the recent findings of adipose tissue in the control of metabolism, focusing on its endocrine and thermogenic function.

Obesity, Inflammation, and Periodontal Disease

The prevalence of obesity has increased substantially over the past decades in most industrialized countries. Obesity is a systemic disease that predisposes to a variety of co-morbidities and complications that affect overall health. Cross-sectional studies suggest that obesity is also associated with oral diseases, particularly periodontal disease, and prospective studies suggest that periodontitis may be related to cardiovascular disease. The possible causal relationship between obesity and periodontitis and potential underlying biological mechanisms remain to be established; however, the adipose tissue actively secretes a variety of cytokines and hormones that are involved in inflammatory processes, pointing toward similar pathways involved in the pathophysiology of obesity, periodontitis, and related inflammatory diseases. We provide an overview of the definition and assessment of obesity and of related chronic diseases and complications that may be important in the periodontist’s office. Studies that have examined the association between obesity and periodontitis are reviewed, and adipose-tissue-derived hormones and cytokines that are involved in inflammatory processes and their relationship to periodontitis are discussed. Our aim is to raise the periodontist’s awareness when treating obese individuals.

Gliptins in managing diabetes - Reviewing computational strategy

The pace of anti-diabetic drug discovery is very slow in spite of increasing rate of prevalence of Type 2 Diabetes which remains a major public health concern. Though extensive research steps are taken in the past decade, yet craves for better new treatment strategies to overcome the current scenario. One such general finding is the evolution of gliptins which discriminately inhibits DPP4 (Dipeptidyl peptidase-4) enzyme. Although the mechanism of action of gliptin is highly target oriented and accurate, still its long-term use stands unknown. This step calls for a fast, flexible, and cost-effective strategies to meet the demands of producing arrays of high-content lead compounds with improved efficiency for better clinical success. The present review highlights the available gliptins in the market and also other naturally occurring DPP4 enzyme inhibitors. Along with describing the known inhibitors and their origin in this review, we attempted to identify a probable new lead compounds using advanced computational techniques. In this context, computational methods that integrate the knowledge of proteins and drug responses were utilized in prioritizing targets and designing drugs towards clinical trials with better efficacy. The compounds obtained as a result of virtual screening were compared with the commercially available gliptin in the market to have better efficiency in the identification and validation of the potential DPP4 inhibitors. The combinatorial computational methods used in the present study identified Compound 1: 25022354 as promising inhibitor.

Serum Resistin Level and Progression of Atherosclerosis during Glucocorticoid Therapy for Systemic Autoimmune Diseases

Adipokines are important regulators of several processes, including inflammation and atherosclerosis. In patients with systemic autoimmune diseases, atherosclerosis is accelerated with higher cardiovascular morbidity and mortality. We prospectively investigated the association of adipokines and glucocorticoid therapy with progression of premature atherosclerosis in 38 patients starting glucocorticoid therapy for systemic autoimmune diseases. To detect premature atherosclerosis, carotid ultrasonography was performed at initiation of glucocorticoid therapy and after a mean three-year follow-up period. The ankle-brachial pressure index and cardio-ankle vascular index (CAVI) were measured. Serum adipokine levels were determined with enzyme-linked immunosorbent assay kits. Twenty-three patients (60.5%) had carotid artery plaque at baseline. The carotid artery intima-media thickness (IMT) increased significantly during follow-up. Glucocorticoids reduced the serum resistin level, while increasing serum leptin and high molecular weight-adiponectin. There was slower progression of atherosclerosis (carotid IMT and CAVI) at follow-up in patients with greater reduction of serum resistin and with higher cumulative prednisolone dose. In conclusion, progression of premature atherosclerosis occurred at an early stage of systemic autoimmune diseases before initiation of glucocorticoid therapy. Since resistin, an inflammation and atherosclerosis related adipokine, is reduced by glucocorticoids, glucocortidoid therapy may not accelerate atherosclerosis in patients with systemic autoimmune diseases.

Resistin's, obesity and insulin resistance: the continuing disconnect between rodents and humans

PURPOSE

This review aimed to discuss the conflicting findings from resistin research in rodents and humans as well as recent advances in our understanding of resistin's role in obesity and insulin resistance.

METHODS

A comprehensive review and synthesis of resistin's role in obesity and insulin resistance as well as conflicting findings from resistin research in rodents and humans.

RESULTS

In rodents, resistin is increased in high-fat/high-carbohydrate-fed, obese states characterized by impaired glucose uptake and insulin sensitivity. Resistin plays a causative role in the development of insulin resistance in rodents via 5' AMP-activated protein kinase (AMPK)-dependent and AMPK-independent suppressor of cytokine signaling-3 (SOCS-3) signaling. In contrast to rodents, human resistin is primarily secreted by peripheral-blood mononuclear cells (PBMCs) as opposed to white adipocytes. Circulating resistin levels have been positively associated with central/visceral obesity (but not BMI) as well as insulin resistance, while other studies show no such association. Human resistin has a role in pro-inflammatory processes that have been conclusively associated with obesity and insulin resistance. PBMCs, as well as vascular cells, have been identified as the primary targets of resistin's pro-inflammatory activity via nuclear factor-κB (NF-κB, p50/p65) and other signaling pathways.

CONCLUSION

Mounting evidence reveals a continuing disconnect between resistin's role in rodents and humans due to significant differences between these two species with respect to resistin's gene and protein structure, differential gene regulation, tissue-specific distribution, and insulin resistance induction as well as a paucity of evidence regarding the resistin receptor and downstream signaling mechanisms of action.

Genetic Background, Adipocytokines, and Metabolic Disorders in Postmenopausal Overweight and Obese Women

The relationship between the genetic background, adipocytokines, and metabolic state in postmenopausal women has not yet been fully described. The aim of this study was to determine the relationship between PPAR gamma-2 (Pro12Ala, C1431T) and ADRB3 (Trp64Arg) polymorphisms and serum adipocytokines (adiponectin, visfatin, and resistin) and metabolic disorders in 176 postmenopausal women with increased body mass (BMI ≥ 25 kg m(-2)). The distributions of selected alleles and genotype frequencies were determined with the PCR-RFLP method. The bioimpedance method was used to determine nutritional status, and enzyme-linked immunosorbent assays were applied to determine serum concentrations of adipocytokines. Viscerally obese postmenopausal women had higher body mass, body fat content, serum glucose, insulin, total cholesterol, LDL, triglycerides, uric acid, and HOMA-IR and a higher prevalence of the Ala12 allele. In models based on cytokine concentration, higher body mass and glucose concentration (visfatin model, p = 0.008) and higher insulin and triglyceride levels (resistin model, p = 0.002) were observed in visceral fat deposition and this was potentiated by the presence of the T1431 allele. In resistin models, co-existence of Ala12/X polymorphisms with the T1431 allele was associated with higher resistin and triglyceride concentrations (p = 0.045). In postmenopausal women, metabolic parameters are mainly determined by the distribution of body fat, but Ala12/X polymorphism may increase the metabolic disorders and this effect can be enhanced by the T1431 allele.

Genetic Determination of Serum Levels of Diabetes-Associated Adipokines

Adipose tissue secretes an abundance of proteins. Some of these proteins are known as adipokines and adipose-derived hormones which have been linked with metabolic disorders, including type 2 diabetes, and even with cancer. Variance in serum adipokine concentration is often closely associated with an increase (obesity) or decrease (lipodystrophy) in fat tissue mass, and it is affected by age, gender, and localization of the adipose tissue. However, there may be genetic variants which, in consequence, influence the serum concentration of a certain adipokine, and thereby promote metabolic disturbances or, with regard to the "protective" allele, exert beneficial effects. This review focuses on the genetic determination of serum levels of the following adipokines: adiponectin, chemerin, leptin, progranulin, resistin, retinol binding protein 4, vaspin, adipsin, apelin, and omentin. The article reports on the latest findings from genome-wide association studies (GWAS) and candidate gene studies, showing variants located in/nearby the adipokine genes and other (non-receptor) genes. An extra chapter highlights adipokine-receptor variants. Epigenetic studies on adipokines are also addressed.

Effect of alcohol on adipose tissue: a review on ethanol mediated adipose tissue injury

BACKGROUND

Alcohol consumption has been in existence in the world for many centuries and it is the major cause of death and injury worldwide. Alcoholic liver disease (ALD) is caused due to excess and chronic alcohol intake. Studies across the globe have identified several pathways leading to ALD. Adipose tissue which has been considered as an energy storage organ is also found to play a major role in ALD progression by secreting hormones and cytokines known as adipokines or adipocytokines. Ethanol affects the metabolic and innate immune activities of adipose tissue contributing to alcohol-induced injury of the tissues.

OBJECTIVE

We aimed at 1) summarizing the metabolism and progression of ALD 2) summarizing about the structure and effect of ethanol induced oxidative stress on adipose tissue 3) reviewing the available data on the effect of ethanol on adipose tissue mass and adipokine secretion in both rodent models and alcoholic patients.

METHODS

The article is summarized based on the original literature and reviews in studying the effect of ethanol on adipose tissue.

RESULTS

Studies on alcoholic patients and rodent models has shown that chronic ethanol consumption reduces adipose tissue mass and causes CYP2E1 mediated oxidative stress and inflammation of adipose tissue. Further hyperlipolysis is observed in adipose tissue that leads to excess fatty acid release that gets transported and deposited in the liver resulting in hepatic steatosis.

CONCLUSION

Studies show that adipose tissue plays a major role in the progression of ALD. So understanding of the mechanisms linking ethanol induced adipose tissue injury with ALD progression would help us in identifying potential therapeutic targets.

Changes in adipokine levels in autism spectrum disorders

BACKGROUND AND OBJECTIVE

The etiopathogenesis of autism spectrum disorders (ASD) is largely unknown, but it seems to involve dysfunction in several biological systems. Among many possible biological pathways, the immune system has emerged as potentially involved. Recent studies have shown association between cytokines (molecules that mediate immune cell interaction) and ASD. Adipokines are cytokines secreted mainly by adipose tissue and may have systemic effects. The main objective of this study was to compare the plasma levels of three adipokines between patients with ASD and healthy controls. Another aim was to correlate the levels of these adipokines and the severity of autistic symptoms as measured by the Social Responsiveness Scale (SRS).

METHODS

We collected plasma from 30 patients and 19 controls and measured the levels of adiponectin, leptin and resistin using a commercially available kit. We also used the SRS as a tool to assess the severity of autistic symptoms.

RESULTS

We found decreased levels of resistin, increased levels of leptin and unaltered levels of adiponectin in plasma from ASD subjects in comparison with controls. There was also a negative correlation between the levels of adiponectin and the severity of symptoms as assessed by the SRS.

CONCLUSION

There are significant changes in the plasma levels of adipokines from patients with ASDs. They suggest the occurrence of systemic changes in ASD and may be hallmarks of the disease.

Human resistin and the RELM of Inflammation in diabesity

The initial discovery of resistin and resistin-like molecules (RELMs) in rodents suggested a role for these adipocytokines in molecular linkage of obesity, Type 2 Diabetes mellitus and metabolic syndrome. Since then, it became apparent that the story of resistin and RELMs was very much of mice and men. The putative role of this adipokine family evolved from that of a conveyor of insulin resistance in rodents to instigator of inflammatory processes in humans. Structural dissimilarity, variance in distribution profiles and a lack of corroborating evidence for functional similarities separate the biological functions of resistin in humans from that of rodents. Although present in gross visceral fat deposits in humans, resistin is a component of inflammation, being released from infiltrating white blood cells of the sub-clinical chronic low grade inflammatory response accompanying obesity, rather than from the adipocyte itself. This led researchers to further explore the functions of the resistin family of proteins in inflammatory-related conditions such as atherosclerosis, as well as in cancers such as endometrial and gastric cancers. Although elevated levels of resistin have been found in these conditions, whether it is causative or as a result of these conditions still remains to be determined.

Obesity related adipokines and colorectal cancer: a review and meta-analysis

Obesity has been considered as an important risk factor for the development of colorectal cancer (CRC), but the association has not been fully elucidated. Obesity is linked significantly to adipose tissue dysfunction and to alteration of adipokines in blood; in particular, obesity-induced inflammation is thought to be an important link between obesity and colorectal cancer. Based on epidemiological studies, we undertook a systematic review to understand the association of circulating levels of selected adipokines, including adiponectin, leptin, resistin, IL-6 and TNF-α, with the level of CRC risk. Most prospective studies suggested protective effects of adiponectin, but these were attenuated by body mass index (BMI) and waist circumference (WC) data in our meta-analysis. On the other hand, meta-analyses for leptin and CRC did not demonstrate any association, similar to the results of systematic review. Although it proved difficult to determine whether other selected adipokines (resistin, IL-6 and TNF-α) were related to CRC risk due to small number of reports, the present systematic review suggested a positive association with elevated resistin levels but null associations with IL-6 and TNF-α.

Association between adipokines and coronary artery lesions in children with Kawasaki Disease

Body fat is an important source of adipokine, which is associated with energy balance and inflammatory and immune responses. However, the role of adipokines in coronary artery complications in Kawasaki disease (KD) has not yet been fully explained. We investigated whether serum adipokine level can be a useful marker for patients with KD who are at higher risk of developing coronary artery lesion (CAL). We measured adipokine levels and other inflammatory parameters in 40 patients with KD, 32 febrile controls, and 15 afebrile controls. Interleukin (IL)-6, tumor necrosis factor (TNF)-α and other laboratory parameters were also measured before and after intravenous immunoglobulin therapy, and in the convalescent phase. At admission, the serum resistin levels in KD children were significantly higher than those in controls (177.56 ng/mL in KD children, 76.48 ng/mL in febrile controls, and 17.95 ng/mL in afebrile controls). In patients with KD, resistin levels were significantly associated with decreased hemoglobin levels (P=0.049) and increased IL-6 levels (P=0.014). The serum IL-6 levels were significantly higher and body mass index was significantly lower in the group of KD with CALs than those without CALs (228.26 ng/mL vs. 39.18 ng/mL and 15.09 vs. 16.60, respectively). In conclusion, resistin is significantly elevated in KD patients, although it has no prognostic value of predicting coronary artery lesion in the acute stage.

Resistin gene variations are associated with the metabolic syndrome in Japanese men

SUMMARY

OBJECTIVES

Metabolic syndrome is defined as a cluster of risk factors for cardiovascular disease and is intimately related to insulin resistance. Resistin, a hormone secreted by adipocytes, may play an important role in communication between adiposity and insulin resistance. We investigated whether variations in the resistin gene associated with metabolic syndrome in a Japanese population.

METHOD

We analyzed five SNPs, two of which were located in the promoter region (-420C > G, -358G > A), two in intron 2 (+157C > T, +299G > A), and one in the 3'-untranslated region (3'UTR) (+1263G > C) across the resistin gene in 2968 residents from an urban Japanese cohort. The associations of SNPs and haplotypes with metabolic syndrome were analyzed.

RESULTS

The GAC and CGC haplotypes (comprising -420C > G, -358G > A, and +157C > T) had opposite influences on metabolic syndrome susceptibility in men; the former was associated with an increased risk and the latter with a decreased risk. We also found that the -420G allele was significantly associated with an increased risk of metabolic syndrome and significantly correlated with high diastolic blood pressure, high HOMA-IR values, high serum triglyceride levels, low HDL-cholesterol levels and high serum levels of adiponectin.

CONCLUSION

We identified a risk-conferring SNP and haplotype of the resistin gene for metabolic syndrome in a Japanese population. Our data suggested that resistin gene is a susceptibility gene for metabolic syndrome in Japanese men.

Resistin in serum and gingival crevicular fluid as a marker of periodontal inflammation and its correlation with single-nucleotide polymorphism in human resistin gene at -420

AIMS

Resistin is an adipocytokine, which have been studied for its role in insulin resistance and recently in inflammation. The aim of the present study is to assess the concentration of resistin in serum and gingival crevicular fluid (GCF) and to compare the levels between subjects with and without periodontitis and type 2 diabetes mellitus (T2DM) and to further correlate the resistin levels with the single-nucleotide polymorphism (SNP) at -420.

SETTING AND DESIGNS

A total of 96 subjects (48 males and 48 females) were divided on the basis of gingival index (GI), probing pocket depth (PD), clinical attachment level (CAL) and hemoglobin A1c levels into healthy (group 1, n = 24), uncontrolled-diabetes related periodontitis (group 2, n = 24), controlled-diabetes related periodontitis (group 3, n = 24) and chronic periodontitis without T2DM (group 4, n = 24).

MATERIALS AND METHODS

The GCF and serum levels of resistin were quantified using the enzyme-linked immunosorbent assay and compared among the study groups. Further, the association of the resistin levels with periodontal inflammation and SNP at -420 was studied.

RESULTS AND CONCLUSION

The resistin levels in GCF and serum from patients with periodontitis or diabetes mellitus related periodontitis (controlled or uncontrolled) were higher than that of healthy subjects and correlated positively with GI. Further, subjects with GG genotype at -420 showed significantly higher GI, PD, CAL as compared with genotype group CC. Resistin was detected in all serum and GCF samples and was significantly higher in periodontitis. Further, GG genotype at -420 was associated significantly with periodontal inflammation and resistin levels.

Rapid cloning and comparative sequence analysis of full-length cDNA of Rhesus monkey (Macaca mulatta) resistin

Resistin protein is thought to link insulin resistance in murine models of obesity and type-2 diabetes, but the role of resistin in human studies of inflammatory metabolic disorders have generated conflicting data. Here, we describe the structure of the resistin gene using adipose tissue from non-human primates (NHPs), which have been used extensively to model a host of human diseases. Full-length cDNA from rhesus macaque resistin obtained by rapid amplification of cDNA ends (RACE) is comprised of 526 nucleotides covering an open-reading frame (ORF) that encodes a 108-amino-acid protein that is 92% homologous with the human counterpart but only 60% homologous with the murine counterpart. Using a modified polymerase chain reaction technique, we identified single nucleotide polymorphisms and a 78-bp deletion within resistin cDNA of nine rhesus macaques. Comparisons of the full-length cDNA sequence and an amplified 569-bp genomic DNA sequence revealed an error in published predictions arising from genomic studies about the gene's exon 3 region. Our data show, for the first time, the full-length macaque resistin cDNA sequence (GenBank: JF740676.1). These findings will illuminate future studies into the role of resistin in NHP models of inflammatory metabolic diseases.

The brain–adipose axis: A review of involvement of molecules

Many molecules are involved in the regulation of feeding behavior, and they and their receptors are located in the brain hypothalamus and adipocytes. On the basis of evidence suggesting an association between the brain and adipose tissue, we propose the concept of the brain-adipose axis. This model consists of (l) the expression of endogenous molecules and/or their receptors in the hypothalamus and peripheral adipose tissue, (2) the function of these molecules as appetite regulators in the brain, (3) their existence in the general circulation as secreted proteins and (4) the physiological affects of these molecules on fat cell size and number. These molecules can be divided into two anorexigenic and orexigenic classes. In adipose tissue, all orexigenic molecules possess adipogenic activity, and almost all anorexigenic molecules suppress fat cell proliferation. Although the manner, in which they present in the circulating blood connect the brain and peripheral adipocytes, remains to be well-organized, these observations suggest the positive feedback axis affecting molecules in the hypothalamus and adipose tissue. Analysis of the disturbance and dysregulation of this axis might promote the development of new anti-obesity drugs useful in treating the metabolic syndrome.

Resistin and all-cause and cardiovascular mortality: effect modification by adiponectin in end-stage kidney disease patients

BACKGROUND

Resistin is a major adipose tissue cytokine implicated in insulin resistance, inflammation and vascular damage. This cytokine is raised in patients with end-stage kidney disease (ESKD) but the relationship between resistin and major clinical outcomes has not been investigated in this population.

METHODS

We studied the mutual relationship between resistin and the two major adipokines (adiponectin and leptin) and the interaction between resistin and adiponectin (ADPN) and all-cause and cardiovascular (CV) mortality in a cohort of 231 haemodialysis patients followed up for 57 ± 44 months.

RESULTS

Plasma resistin was substantially raised in ESKD patients when compared with healthy subjects (P < 0.001). On univariate analysis, resistin was related inversely to ADPN (r = -0.14, P = 0.04) and directly to C-reactive protein (r = 0.15, P = 0.03), but was largely independent of leptin (r = 0.08, P = 0.24) and the HOMA-IR index (r = -0.04, P = 0.51). During the follow-up, 165 patients died (96 for CV causes). On both univariate (all-cause mortality: P = 0.004; CV mortality P < 0.001) and multivariate (all-cause mortality: P = 0.01; CV mortality P < 0.001) Cox regression analyses, the effect of resistin on study outcomes was closely dependent on ADPN levels. There was a consistent excess risk for all-cause (P = 0.002) and CV mortality (P = 0.003) by plasma resistin (20 ng/mL) in patients in the first ADPN tertile, but no risk excess for these outcomes was apparent in patients in the third tertile.

CONCLUSION

This study indicates that resistin predicts death and fatal CV events depending on plasma ADPN levels. These findings underscore the importance of the interaction among adipokines for the prediction of adverse clinical outcomes in ESKD.

Association of cardiac changes with serum adiponectin and resistin levels in obese and overweight children

OBJECTIVES

To investigate serum adiponectin and resistin levels in childhood obesity and their relationship with cardiac changes and insulin resistance.

METHODS

Seventy-one obese and 24 overweight children and 40 healthy children and adolescents were selected for the study. Height and weight measurements, BMI values and BMI SD score values were obtained for each individual. After blood pressure measurement, left ventricular wall thickness, left ventricular mass, stroke volume, cardiac output, systolic and diastolic functions of the left ventricle were measured using an M-mode, two dimensional color-coded echocardiography device. Blood samples of the individuals were obtained for fasting blood sugar, total blood cholesterol, triglyceride, low-density lipoprotein (LDL) cholesterol, very low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, insulin, C-peptide, adiponectin and resistin values.

RESULTS

Cholesterol and LDL values, homeostasis model assessment of insulin resistance, fasting insulin and fasting C-peptide values of the obese and overweight groups were higher (P<0.01). Adiponectin level (P<0.001) and resistin level (P<0.05) of the obese and overweight groups were lower than those of the control group (P<0.05). Echocardiographic evaluation showed diastolic dysfunction in addition to increased left ventricular wall thickness and left ventricle mass values in the obese and overweight children. We also detected a significant positive correlation among left ventricular mass, interventricular septum systolic diameter and resistin in obese children. Among the factors, resistin level was determined as an independent predictor of left ventricular mass in obese children.

CONCLUSION

In this study, even in asymptomatic obese and overweight children, cardiac structural and functional changes, such as increased left ventricular mass and diastolic dysfunction, were demonstrated. Although decreased adiponectin level was not related to cardiac changes, it was shown that decreased serum resistin levels in the obese cases lead to left ventricle hypertrophy.

Whole-body cryostimulation as an effective method of reducing low-grade inflammation in obese men

This study was aimed to evaluate anti-inflammatory effect of the whole body cryostimulation in obese men. Fourteen subjects (BMI >30 kg m⁻²), divided into two subgroups according to cardiorespiratory fitness: higher (HCF) or lower (LCF), have been exposed to 10 sessions in a cryogenic chamber (−110 °C). Blood samples were collected before, 30 min and 24 h after the first, fifth and last cryostimulation. Coldness exposures affected blood cytokine profile; however, the response depended on subjects’ fitness capacity. Concentrations of pro-inflammatory cytokines in the LCF decreased by 19, 6.8, and 7.4 % in IL-6, resistin, and visfatin, respectively. TNFα in the LCF dropped 4.3-fold compared to baseline, while in the HCF, changes were smaller, yet significant. Anti-inflammatory cytokine IL-10 increased in both groups. No changes in adiponectin and leptin were observed in either group. Obtained results suggest that whole body cryostimulation can be a supplementary method for obese in reducing systemic inflammation.

Human resistin inhibits myogenic differentiation and induces insulin resistance in myocytes

This study is aimed to investigate the effect of human resistin on myocyte differentiation and insulin resistance. The human resistin eukaryotic expression vector was stable transfected into C2C12 myocyte cells and was transiently transfected into COS7 cells. The effects of human resistin on cell proliferation, cell cycle, and myogenic differentiation of C2C12 cells were examined. Glucose uptake assays was performed on C2C12 myotubes by using [³H] 2-deoxy-D-glucose. The mRNA levels of insulin receptor (IR) and glucose transporter 4 (GLUT4) were evaluated by semiquantitative RT-PCR. Results showed by the C2C12 cells transfected with human resistin gene compared with that without transfecting gene are as follows: (1) cell proliferation was significantly promoted, (2) after inducing differentiation, the myotube's diameters and expression of desmin and myoglobin decreased, and (3) glucose uptake ratio was lowered and expression of IR and GLUT4 decreased. However, there was no significant difference in the glucose uptake ratio between C2C12 myotubes treated with a human resistin conditioned medium of COS7 cells and treated with control medium. These results suggest that maybe human resistin has not a direct role on insulin sensitivity of myocytes. However, maybe it impaired the insulin sensitivity of myocytes through suppressing myogenesis and stimulating proliferation of myoblasts.

Adipokine inflammation and insulin resistance: the role of glucose, lipids and endotoxin

Adipose tissue is an active endocrine organ, and our knowledge of this secretory tissue, in recent years, has led us to completely rethink how our body functions and becomes dysregulated with weight gain. Human adipose tissue appears to act as a multifunctional secretory organ with the capacity to control energy homoeostasis through peripheral and central regulation of energy homoeostasis. It also plays an important role in innate immunity. However, the capability to more than double its original mass to cope with positive energy balance in obesity leads to many pathogenic changes. These changes arise within the adipose tissue as well as inducing secondary detrimental effects on other organs like muscle and liver, including chronic low-grade inflammation mediated by adipocytokines (adipokine inflammation). This inflammation is modulated by dietary factors and nutrients including glucose and lipids, as well as gut bacteria in the form of endotoxin or LPS. The aim of this current review is to consider the impact of nutrients such as glucose and lipids on inflammatory pathways, specifically within adipose tissue. Furthermore, how nutrients such as these can influence adipokine inflammation and consequently insulin resistance directly through their effects on secretion of adipocytokines (TNFα, IL6 and resistin) as well as indirectly through increases in endotoxin is discussed.