Influence of exogenous leptin on redox homeostasis in neutrophils and lymphocytes cultured in synovial fluid isolated from patients with rheumatoid arthritis

Leptin plays a role in the multiplication of and inflammation in ovarian granulosa cells in polycystic ovary syndrome through the JAK1/STAT3 pathway

OBJECTIVES

The authors determined the level of Expression of Leptin (LEP) in Polycystic Ovary Syndrome (PCOS) patients with or without obesity and in GCs treated with insulin.

METHODS

LEP expression was first assessed in ovary cortex specimens collected from women with PCOS with or without obesity as well as from healthy controls. Ovarian Granulosa Cells (OGCs) induced by insulin extracted from a mouse model were used in further functional research.

RESULTS

Real-time PCR and western blotting indicated that LEP expression was upregulated in GCs induced by insulin, in comparison with that in GCs not induced by insulin. Furthermore, the knockdown of LEP resulted in a reduction in growth and multiplication and an increase in apoptosis and inflammation in GCs induced by insulin. Next, the authors evaluated the effect of LEP on three key pathways of inflammation (MAPK, NF-kB, and JAK1/STAT3); results showed that the JAK1/STAT3 pathway was induced by LEP knockdown, as evidenced by the upregulation of phosphor-JAK1, phosphor-STAT3, and nuclear STAT3 expression. Administration of curcumin, a specific inhibitor of STAT3, counteracted the effect of LEP knockdown on cell inflammation and apoptosis.

CONCLUSION

The present data suggest that upregulation of LEP expression in the PCOS granulosa cell model is essential for reducing apoptosis and inflammation by modulating the JAK1/STAT3 pathway axis.

A Decreased Response to Resistin in Mononuclear Leukocytes Contributes to Oxidative Stress in Nonalcoholic Fatty Liver Disease

BACKGROUND

Deregulation of immune response and oxidative stress contribute to nonalcoholic fatty liver disease (NAFLD) pathogenesis. Resistin is a physiological modulator of inflammation and redox homeostasis of different cell types. Increased resistin serum concentration and the direct association between resistin hepatic expression and NAFLD severity suggest that resistin participates in NAFLD pathogenesis.

AIMS

To evaluate resistin-induced regulation of redox homeostasis in mononuclear leukocytes from NAFLD patients and controls.

METHODS

We evaluated basal and resistin-mediated modulation of reactive oxygen species (ROS) and glutathione content by flow cytometry, and antioxidant enzyme activities by spectrophotometry.

RESULTS

Peripheral blood mononuclear cells (PBMC) from NAFLD patients showed higher ROS content and glutathione peroxidase activity and lower glutathione content, superoxide dismutase and glutathione reductase activities than control PBMC. Resistin decreased ROS levels and superoxide dismutase activity and increased glutathione reductase and catalase activities in PBMC from controls but not from patients. Resistin decreased glutathione content in PBMC from control and NAFLD patients, with greater effect on patient cells. Basal and resistin-modulated ROS levels were directly associated with obesity-related risk factors for NAFLD. Hepatic myeloid cells and T-lymphocytes from NAFLD patients showed higher basal ROS content than cells from controls. Resistin decreased ROS levels in hepatic T-lymphocytes from controls but not from patients.

CONCLUSIONS

Resistin regulates redox homeostasis in mononuclear leukocytes. A decreased response to resistin in leukocytes from NAFLD patients is associated with an impaired redox homeostasis.

Effect of Leptin on Chronic Inflammatory Disorders: Insights to Therapeutic Target to Prevent Further Cardiovascular Complication

In response to obesity-associated chronic inflammatory disorders, adipose tissue releases a biologically active peptide known as leptin. Leptin activates the secretion of chemical mediators, which contribute to the pathogenesis of chronic inflammatory disorders, such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and psoriasis. Conversely, adiposity and obesity are the major aggravating risk factors in the pathogenesis of metabolic syndrome (MetS), including type II diabetes mellitus and obesity-associated hypertension. Elevated level of leptin in obesity-associated hypertension causes an increase in the production of aldosterone, which also results in elevation of arterial blood pressure. Hyperleptinemia is associated with the progress of the atherosclerosis through secretion of pro-inflammatory cytokines, like interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), IL-17, and other cytokines to promote inflammation. The release of those cytokines leads to chronic inflammatory disorders and obesity-associated MetS. Thus, the aberrant leptin level in both MetS and chronic inflammatory disorders also leads to the complication of cardiovascular diseases (CVD). Therapeutic target of leptin regarding its pro-inflammatory effect and dysregulated sympathetic nervous system activity may prevent further cardiovascular complication. This review mainly assesses the mechanism of leptin on the pathogenesis and further cardiovascular risk complication of chronic inflammatory disorders.

Correlation between leptin and IFN-γ involved in granulosa cell apoptosis in PCOS

OBJECTIVES

Our study aimed to explore the relationship between leptin and IFN-γ in PCOS patients, and confirmed the effect of leptin-induced IFN-γ on granulosa cells furtherly.

METHODS

29 patients with PCOS and 36 healthy controls were enrolled. Leptin level and the proportion of Th1 cells were detected and association between them were analyzed. Meanwhile, peripheral blood mononuclear cells (PBMCs) isolated from PCOS patients were treated with leptin and then the proportion of Th1 was analyzed. Besides that, the apoptotic level of KGN cells was monitored after IFN-γ treatment.

RESULTS

In the circulation of PCOS patients, leptin level dramatically increased compared with controls. And, this was associated with upregulated Th1 cells proportion and IFN-γ level. In vitro, Th1 cells proportion increased after leptin treated PBMCs from PCOS patients. Furthermore, for KGN cells, the percentage of live cells decreased and later apoptosis cells increased after IFN-γ treatment.

CONCLUSIONS

Our results indicated that leptin takes part in process of PCOS via inducing expression of IFN-γ. Our findings highlight the importance of the connection between leptin and inflammation in PCOS and provide new insights therapeutic strategy for this disease.

Insulin and obesity transform hypothalamic-pituitary-adrenal axis stemness and function in a hyperactive state

Objective

Metabolic diseases are an increasing problem in society with the brain-metabolic axis as a master regulator of the human body for sustaining homeostasis under metabolic stress. However, metabolic inflammation and disease will trigger sustained activation of the hypothalamic-pituitary-adrenal axis. In this study, we investigated the role of metabolic stress on progenitor cells in the hypothalamic-pituitary-adrenal axis.

Methods

In vitro, we applied insulin and leptin to murine progenitor cells isolated from the pituitary and adrenal cortex and examined the role of these hormones on proliferation and differentiation. In vivo, we investigated two different mouse models of metabolic disease, obesity in leptin-deficient ob/ob mice and obesity achieved via feeding with a high-fat diet.

Results

Insulin was shown to lead to enhanced proliferation and differentiation of both pituitary and adrenocortical progenitors. No alterations in the progenitors were noted in our chronic metabolic stress models. However, hyperactivation of the hypothalamic-pituitary-adrenal axis was observed and the expression of the appetite-regulating genes Npy and Agrp changed in both the hypothalamus and adrenal.

Conclusions

It is well-known that chronic stress and stress hormones such as glucocorticoids can induce metabolic changes including obesity and diabetes. In this article, we show for the first time that this might be based on an early sensitization of stem cells of the hypothalamic-pituitary-adrenal axis. Thus, pituitary and adrenal progenitor cells exposed to high levels of insulin are metabolically primed to a hyper-functional state leading to enhanced hormone production. Likewise, obese animals exhibit a hyperactive hypothalamic-pituitary-adrenal axis leading to adrenal hyperplasia. This might explain how stress in early life can increase the risk for developing metabolic syndrome in adulthood.

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Insulin enhances proliferation and differentiation of adrenocortical and pituitary progenitors.

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Obesity leads to hyperactivation and priming of the HPA axis.

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Obesity leads to overexpression of appetite-regulating genes in the hypothalamus.

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Obesity leads to a decrease in the expression of appetite-regulating genes in the adrenal gland.

Adipocytokines: Are they the Theory of Everything?

INTRODUCTION

Adipose tissue secretes various bioactive peptides/proteins, immune molecules and inflammatory mediators which are known as adipokines or adipocytokines. Adipokines play important roles in the maintenance of energy homeostasis, appetite, glucose and lipid metabolism, insulin sensitivity, angiogenesis, immunity and inflammation. Enormous number of studies from all over the world proved that adipocytokines are involved in the pathogenesis of diseases affecting nearly all body systems, which raises the question whether we can always blame adipocytokines as the triggering factor of every disease that may hit the body.

OBJECTIVE

Our review targeted the role played by adipocytokines in the pathogenesis of different diseases affecting different body systems including diabetes mellitus, kidney diseases, gynecological diseases, rheumatologic disorders, cancers, Alzheimer's, depression, muscle disorders, liver diseases, cardiovascular and lung diseases.

METHODOLOGY

We cited more than 33 recent literature reviews that discussed the role played by adipocytokines in the pathogenesis of different diseases affecting different body systems.

CONCLUSION

More evidence is being discovered to date about the role played by adipocytokines in more diseases and extra research is needed to explore hidden roles played by adipokine imbalance on disease pathogenesis.

Adipocytokines in Rheumatoid Arthritis: The Hidden Link between Inflammation and Cardiometabolic Comorbidities

Rheumatoid arthritis is a chronic autoimmune disease affecting typically synovial joints and leading to progressive articular damage, disability, and reduced quality of life. Despite better recent therapeutic strategies improving long-term outcomes, RA is associated with a high rate of comorbidities, infections, malignancies, and cardiovascular disease (CVD). Remarkably, some well-known pathogenic proinflammatory mediators in RA, such as interleukin-1β (IL-1β) and tumor necrosis factor (TNF), may play a pivotal role in the development of CVD. Interestingly, different preclinical and clinical studies have suggested that biologic agents commonly used to treat RA patients may be effective in improving CVD. In this context, the contribution of adipocytokines has been suggested. Adipocytokines are pleiotropic molecules, mainly released by white adipose tissue and immune cells. Adipocytokines modulate the function of different tissues and cells, and in addition to energy homeostasis and metabolism, amplify inflammation, immune response, and tissue damage. Adipocytokines may contribute to the proinflammatory state in RA patients and development of bone damage. Furthermore, they could be associated with the occurrence of CVD. In this study, we reviewed available evidence about adipocytokines in RA, because of their involvement in disease activity, associated CVD, and possible biomarkers of prognosis and treatment outcome and because of their potential as a possible new therapeutic target.

Leptin and Leptin Resistance in the Pathogenesis of Obstructive Sleep Apnea: A Possible Link to Oxidative Stress and Cardiovascular Complications

Obesity-related sleep breathing disorders such as obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS) cause intermittent hypoxia (IH) during sleep, a powerful trigger of oxidative stress. Obesity also leads to dramatic increases in circulating levels of leptin, a hormone produced in adipose tissue. Leptin acts in the hypothalamus to suppress food intake and increase metabolic rate. However, obese individuals are resistant to metabolic effects of leptin. Leptin also activates the sympathetic nervous system without any evidence of resistance, possibly because these effects occur peripherally without a need to penetrate the blood-brain barrier. IH is a potent stimulator of leptin expression and release from adipose tissue. Hyperleptinemia and leptin resistance may upregulate generation of reactive oxygen species, increasing oxidative stress and promoting inflammation. The current review summarizes recent data on a possible link between leptin and oxidative stress in the pathogenesis of sleep breathing disorders.

Significance of preoperative neutrophil-lymphocyte count ratio on predicting postoperative sepsis after percutaneous nephrolithotomy

We evaluated the usefulness of preoperative neutrophil-lymphocyte count ratio (NLCR) in predicting postoperative sepsis after percutaneous nephrolithotomy (PCNL). In total, 487 patients who underwent PCNL for renal stones were included in the present retrospective study. The stone burden, number of tracts and location, operation time, fluoroscopy time, presence of residual stones, and blood transfusion rates were postoperatively recorded in all patients. All patients were followed up for signs of systemic inflammatory response syndrome (SIRS) and sepsis. The association of sepsis/SIRS with the risk factors of infectious complications, including NLCR, was evaluated. SIRS was detected in 91 (18.7%) patients, 25 (5.1%) of whom were diagnosed with sepsis. Stone burden, operation time, irrigation rate, previous surgery, nephrostomy time, access number, blood transfusion, residual stone, postoperative urinary culture, renal pelvis urinary culture, and stone culture were found to be predictive factors for SIRS and sepsis development. Receiver operating characteristic curve analysis revealed an NLCR cutoff of 2.50 for predicting the occurrence of SIRS/sepsis. We found that the incidence of sepsis was significantly higher in patients with NLCR ≥ 2.50 than in patients with NLCR < 2.50 (p = 0.006). Preoperative and postoperative urine culture positivity were associated with high NLCR (p = 0.039 and p = 0.003, respectively). We believe that preoperative NLCR may be a promising additive predictor of bacteremia and postoperative sepsis in patients who undergo PCNL for renal stones. This marker is simple, easily measured, and easy to use in daily practice without extra costs.