Leptin promotes differentiation and survival of human dendritic cells and licenses them for Th1 priming

A systematic review on leptin's role in defining cancer: special emphasis on immunomodulation, inflammation, and therapeutic interventions

Leptin, an adipokine related to obesity, is mainly known for its role in regulating energy homeostasis and appetite by working via the leptin receptor. Recently, different groups have demonstrated that apart from adipocytes, specific cell types associated with cancer and tumor microenvironments express leptin and leptin receptors. This tumor microenvironment-associated leptin-leptin receptor signaling contributes to the different hallmarks of cancer, ranging from inflammatory changes to metastasis. Eventually, it has also been reported that high serum level of leptin, a characteristic of obese people, is linked to enhanced tumor growth. On the other hand, leptin can influence both innate as well as adaptive immunity related to cancer. Overall, leptin's role in modulating cancer is controversial. So, in this review, we summarized the role of leptin in shaping different forms of cancer that are influenced by leptin-leptin receptor signaling with special emphasis on immunomodulation and inflammatory events and also discussed the possible therapeutic interventions to date. As this review work, with the collection of different updated knowledge, has summarized the role of leptin on cancer, it would be useful material to have on hand for both beginners as well as pioneers of these and related fields.

Leptin and Iinterlukin-6 relationship and influence of mortality in sepsis

BACKGROUND

Sepsis is a severe and life-threatening disease involving multiple risk factors. Leptin has been suggested to play a role in modulating the inflammatory response in sepsis and improving outcomes; however, there are conflicting results regarding the outcome of sepsis. The present study aims to clarify the expression of leptin in patients with sepsis, and its association with other cytokines.

METHOD

The retrospective study enrolled 165 adults with sepsis from medical intensive care units (ICU)s, and collected leptin, glucose levels, and cytokines such as IL-6, IL-1RA, IL-10, IL-17, TNF-α, IFN-γfor analysis. Leptin levels were divided into three groups based on concentration: Low (≤ 3.78 ng/mL), Medium (3.78 < leptin ≤ 23.2 ng/mL), and High (> 23.2 ng/mL). Survival curve analysis and comparisons among groups were performed. A subgroup analysis by sex (male and female) was also conducted. Finally, a multiple-factor logistic regression model was used to evaluate the interaction between leptin and other factors.

RESULT

The high leptin groups were the oldest (low vs. medium vs. high: 60 vs. 66 vs. 78, p < 0.0001) and had the highest body mass index (BMI) (19.8 vs. 23.9 vs. 24.2, p < 0.0001), the highest percentages of women (28.6 vs. 34.1 vs. 65.9 p = 0.001), and the most comorbidities (1 vs. 1 vs. 2, p = 0.001). After controlling IL-6, day 1 leptin had a trend associated with lower mortality in the hospital (β = 0.984, p = 0.062). The highest IL-6 group had a significantly higher mortality rate among three IL-6 level patients (p = 0.015), but in the high leptin subgroup analysis, the significant effect of high IL-6 on mortality disappeared. Besides, the subgroup analysis of men, the high leptin group had a trend of better survival than the medium and low leptin groups.

CONCLUSION

High leptin levels may mitigate the adverse prognostic impact of elevated IL-6 on septic mortality. At comparable IL-6 levels, leptin could serve as a predictor of septic outcomes. Leptin might act as a protective factor in men. Future research should explore leptin's role in IL-6-mediated inflammation and its potential protective effect in high IL-6 sepsis cases.

Identification and validation of key biomarkers associated with immune and oxidative stress for preeclampsia by WGCNA and machine learning

Background

Preeclampsia (PE), a major obstetric disorder marked by dysfunction in both placental and maternal vascular systems, continues to pose critical challenges in global maternal healthcare. This multisystem pregnancy complication contributes significantly to adverse perinatal outcomes and remains a leading cause of pregnancy-related morbidity worldwide. However, the available treatment options at present remain restricted. Our investigation employs an integrative bioinformatics approach to elucidate critical molecular signatures linked to the interplay between immunological dysregulation and oxidative stress mechanisms in PE pathogenesis.

Methods

In this study, we sourced the dataset from the GEO database with the aim of pinpointing differentially expressed genes (DEGs) between PE samples and control samples. Genes associated with oxidative stress were procured from the Genecards database. Next, we employed a comprehensive approach. This involved integrating WGCNA, GO and KEGG pathway analyses, constructing PPI networks, applying machine learning algorithms, performing gene GSEA, and conducting immune infiltration analysis to identify the key hub genes related to oxidative stress. Diagnostic potential of candidate biomarkers was quantitatively assessed through ROC curve modeling. Additionally, we constructed a miRNA - gene regulatory network for the identified diagnostic genes and predicted potential candidate drugs. In the final step, we validated the significant hub gene using independent external datasets, the hypoxia model of the HTR-8/SVneo cell line, and human placental tissue samples.

Results

At last, leptin (LEP) was identified as a core gene through screening and was found to be upregulated. The results of quantitative real-time polymerase chain reaction (qRT -PCR) and immunohistochemistry validation were consistent with those obtained from the datasets. KEGG analysis revealed that LEP was significantly enriched in "allograft rejection," "antigen processing," "ECM receptor interaction" and "graft versus host disease." GO analysis revealed that LEP was involved in biological processes such as "antigen processing and presentation," "peptide antigen assembly with MHC protein complex," "complex of collagen trimers," "MHC class II protein complex" and "mitochondrial protein containing complex." Moreover, immune cell analysis indicated that T follicular helper cells, plasmacytoid dendritic cells, neutrophils, and activated dendritic cells were positively correlated with LEP expression, whereas γδT cells, eosinophils, and central memory CD4+ T cells showed a negative correlation. These findings suggest that LEP influences the immune microenvironment of PE through its interaction with arious immune cells. In addition, 28 miRNAs and 15 drugs were predicted to target LEP. Finally, the overexpression of LEP was verified using independent external datasets, the hypoxia model of the HTR-8/SVneo cell line, and human placental tissue.

Conclusion

Through an integrated analytical framework employing WGCNA coupled with three distinct machine learning-driven phenotypic classification models, we discovered a pivotal regulatory gene. This gene has the potential to act as a novel diagnostic biomarker for PE. Moreover, it can be considered as a promising target for drug development related to PE. Notably, it shows a strong correlation with the immune microenvironment, suggesting its crucial role in the complex pathophysiological processes underlying PE.

Leptin and Leptin Signaling in Multiple Sclerosis: A Narrative Review

Obesity, a pandemic health problem, is now considered as a chronic inflammatory state, related to many autoimmune diseases, such as multiple sclerosis. Thus, adipokines, inflammatory mediators secreted by adipose tissue, play an important role modulating the immune response. In this context, obesity, especially during adolescent age, seems to be a key factor for the development of multiple sclerosis. Leptin, the main pro-inflammatory adipokine secreted by the adipose tissue, has been found increased in patients with multiple sclerosis and is able to regulate the immune system promoting a pro-inflammatory response. Leptin signaling in both innate and adaptative immune cells might have immunomodulatory effects in the context of multiple sclerosis. In this way, leptin has been found to produce a Th1 and Th17 response, increasing M1 macrophages and decreasing regulatory T cells and Th2 response. Moreover, circulating inflammatory adipokines, such as leptin, have been found in people with multiple sclerosis. In the present work, we are reviewing literature to update the body of knowledge regarding the role of obesity and leptin in multiple sclerosis.

Leptin, NK cells, and the weight of immunity: Insights into obesity

Obesity is a chronic inflammatory disease that affects more than 1 billion people worldwide and is associated with various metabolic and physiological dysfunctions, directly impacting the dynamics of the immune response, partly due to elevated leptin levels. Leptin is an important peptide hormone that regulates neuroendocrine function and energy homeostasis, with its blood levels reflecting energy reserves, fat mass, or energy deprivation. This hormone also plays a fundamental role in regulating immune function, including the activity of NK cells, which are essential components in antiviral and antitumor activity. In obese individuals, leptin resistance is commonly established, however, NK cells and other immune components remain responsive to this hormone. So far, leptin has demonstrated paradoxical activities of these cells, often associated with a dysfunctional profile when associated with obesity. The excessive fat is usually related to metabolic remodeling in NK cells, resulting in compromised antitumor responses due to reduced cytotoxic capacity and decreased expression of cytokines important for these defense mechanisms, such as IFN-γ. Therefore, this review approaches a better understanding of the immunoendocrine interactions between leptin and NK cells in the context of obesity.

Emerging role of metabolic reprogramming in the immune microenvironment and immunotherapy of thyroid cancer

The metabolic reprogramming of cancer cells is a hallmark of many malignancies. To meet the energy acquisition needs of tumor cells for rapid proliferation, tumor cells reprogram their nutrient metabolism, which is caused by the abnormal expression of transcription factors and signaling molecules related to energy metabolic pathways as well as the upregulation and downregulation of abnormal metabolic enzymes, receptors, and mediators. Thyroid cancer (TC) is the most common endocrine tumor, and immunotherapy has become the mainstream choice for clinical benefit after the failure of surgical, endocrine, and radioiodine therapies. TC change the tumor microenvironment (TME) through nutrient competition and metabolites, causing metabolic reprogramming of immune cells, profoundly changing immune cell function, and promoting immune evasion of tumor cells. A deeper understanding of how metabolic reprogramming alters the TME and controls immune cell fate and function will help improve the effectiveness of TC immunotherapy and patient outcomes. This paper aims to elucidate the metabolic communication that occurs between immune cells around TC and discusses how metabolic reprogramming in TC affects the immune microenvironment and the effectiveness of anti-cancer immunotherapy. Finally, targeting key metabolic checkpoints during metabolic reprogramming, combined with immunotherapy, is a promising strategy.

Leptin/LPS-treated dendritic cells reduce the expression of genes involved in tumor tissue metastasis and angiogenesis in an animal model of breast cancer

Leptin, an immune-regulating protein, enhances the maturation of dendritic cells (DCs). We previously demonstrated that leptin and lipopolysaccharide (LPS) promote the expression of co-stimulatory molecules on the surface of DCs. Leptin/LPS-treated DCs increased T cell responses against 4T1 breast cancer in mice. Therefore, in the present study, we investigate the effects of a DC vaccine treated with leptin and LPS on the genes involved in tumor metastasis, angiogenesis, and related cytokines in a mouse model of breast cancer. Tumor induction was achieved through subcutaneous injection of 4T1 cells into syngeneic mice. On days 12 and 19, the mouse groups received the DC vaccine treated with leptin and a combination of leptin and LPS. After sacrificing the mice on day 26, the levels of IL-6 and IL-33 in the serum were assayed using the ELISA technique, and the expression levels of the VEGF, CCL2, MMP9, and CCL5 genes in the tumors were measured by Real-Time PCR. Compared to untreated tumor-bearing mice, the leptin-treated mature DC (mDC) group exhibited a significant reduction in the expression of MMP9 (0.33-fold, p = 0.01) and CCL5 (0.81-fold, p = 0.02). The leptin-LPS-treated mDC group showed decreased expression of genes involved in metastasis and tumor growth, including VEGF (0.72-fold, p = 0.03), MMP9 (0.26-fold, p = 0.001), and CCL5 (0.3-fold, p = 0.006), indicating more efficient prevention of metastasis. The CCL2 gene expression levels in both treatment groups showed a slight decreasing trend, but these changes were not statistically significant. The leptin-treated mDC group reduced IL-6 production by approximately 16% (p = 0.02), while treatment with the leptin-LPS-treated mDC significantly decreased IL-6 production by approximately 22% (p = 0.01) and increased IL-33 production by approximately 42% (p = 0.03). The findings of the present study indicate that the leptin-LPS-treated mDC vaccine group reduced the expression of genes and cytokines involved in metastasis and angiogenesis, demonstrating greater efficacy compared to the leptin-treated mDC vaccine group.

LRH-1/NR5A2 targets mitochondrial dynamics to reprogram type 1 diabetes macrophages and dendritic cells into an immune tolerance phenotype

BACKGROUND

The complex aetiology of type 1 diabetes (T1D), characterised by a detrimental cross-talk between the immune system and insulin-producing beta cells, has hindered the development of effective disease-modifying therapies. The discovery that the pharmacological activation of LRH-1/NR5A2 can reverse hyperglycaemia in mouse models of T1D by attenuating the autoimmune attack coupled to beta cell survival/regeneration prompted us to investigate whether immune tolerisation could be translated to individuals with T1D by LRH-1/NR5A2 activation and improve islet survival.

METHODS

Peripheral blood mononuclear cells (PBMCs) were isolated from individuals with and without T1D and derived into various immune cells, including macrophages and dendritic cells. Cell subpopulations were then treated or not with BL001, a pharmacological agonist of LRH-1/NR5A2, and processed for: (1) Cell surface marker profiling, (2) cytokine secretome profiling, (3) autologous T-cell proliferation, (4) RNAseq and (5) proteomic analysis. BL001-target gene expression levels were confirmed by quantitative PCR. Mitochondrial function was evaluated through the measurement of oxygen consumption rate using a Seahorse XF analyser. Co-cultures of PBMCs and iPSCs-derived islet organoids were performed to assess the impact of BL001 on beta cell viability.

RESULTS

LRH-1/NR5A2 activation induced a genetic and immunometabolic reprogramming of T1D immune cells, marked by reduced pro-inflammatory markers and cytokine secretion, along with enhanced mitohormesis in pro-inflammatory M1 macrophages and mitochondrial turnover in mature dendritic cells. These changes induced a shift from a pro-inflammatory to an anti-inflammatory/tolerogenic state, resulting in the inhibition of CD4+ and CD8+ T-cell proliferation. BL001 treatment also increased CD4+/CD25+/FoxP3+ regulatory T-cells and Th2 cells within PBMCs while decreasing CD8+ T-cell proliferation. Additionally, BL001 alleviated PBMC-induced apoptosis and maintained insulin expression in human iPSC-derived islet organoids.

CONCLUSION

These findings demonstrate the potential of LRH-1/NR5A2 activation to modulate immune responses and support beta cell viability in T1D, suggesting a new therapeutic approach.

KEY POINTS

LRH-1/NR5A2 activation in inflammatory cells of individuals with type 1 diabetes (T1D) reduces pro-inflammatory cell surface markers and cytokine release. LRH-1/NR5A2 promotes a mitohormesis-induced immuno-resistant phenotype to pro-inflammatory macrophages. Mature dendritic cells acquire a tolerogenic phenotype via LRH-1/NR5A2-stimulated mitochondria turnover. LRH-1/NR5A2 agonistic activation expands a CD4+/CD25+/FoxP3+ T-cell subpopulation. Pharmacological activation of LRH-1/NR5A2 improves the survival iPSC-islets-like organoids co-cultured with PBMCs from individuals with T1D.

Adipokine receptor expression in mast cells is altered by specific ligands and proinflammatory cytokines

Adipokines play essential roles in regulating a range of biological processes, but growing evidence indicates that they are also fundamental in immunological mechanisms and, primarily, inflammatory responses. Adipokines mediate their actions through specific receptors. However, although adipokine receptors are widely distributed in many cell and tissue types, limited data are available on their expression in mast cells (MCs) and, consequently, adipokine's significance in the modulation of MC activity within the tissues. In this study, we demonstrate that rat peritoneal MCs constitutively express the leptin receptor (i.e. LEPR), adiponectin receptors (i.e. ADIPOR1 and ADIPOR2) and the chemerin receptor (i.e. CMKLR1). We also found that LEPR, ADIPOR1, ADIPOR2 and CMKLR1 expression in MCs changes in response to stimulation by their specific ligands and some cytokines with potent proinflammatory properties. Furthermore, the involvement of intracellular signaling molecules in leptin-, adiponectin- and chemerin-induced MC response was analyzed. Overall, our findings suggest that adipokines leptin, adiponectin and chemerin can significantly affect the activity of MCs in various processes, especially during inflammation. These observations may contribute significantly to understanding the relationship between adipokines, immune mechanisms and diseases or conditions with an inflammatory component.

The Interplay between Obesity and Inflammation

Obesity is an important condition affecting the quality of life of numerous patients and increasing their associated risk for multiple diseases, including tumors and immune-mediated disorders. Inflammation appears to play a major role in the development of obesity and represents a central point for the activity of cellular and humoral components in the adipose tissue. Macrophages play a key role as the main cellular component of the adipose tissue regulating the chronic inflammation and modulating the secretion and differentiation of various pro- and anti-inflammatory cytokines. Inflammation also involves a series of signaling pathways that might represent the focus for new therapies and interventions. Weight loss is essential in decreasing cardiometabolic risks and the degree of associated inflammation; however, the latter can persist for long after the excess weight is lost, and can involve changes in macrophage phenotypes that can ensure the metabolic adjustment. A clear understanding of the pathophysiological processes in the adipose tissue and the interplay between obesity and chronic inflammation can lead to a better understanding of the development of comorbidities and may ensure future targets for the treatment of obesity.

Vascular remodelling in cardiovascular diseases: hypertension, oxidation, and inflammation

Optimal vascular structure and function are essential for maintaining the physiological functions of the cardiovascular system. Vascular remodelling involves changes in vessel structure, including its size, shape, cellular and molecular composition. These changes result from multiple risk factors and may be compensatory adaptations to sustain blood vessel function. They occur in diverse cardiovascular pathologies, from hypertension to heart failure and atherosclerosis. Dynamic changes in the endothelium, fibroblasts, smooth muscle cells, pericytes or other vascular wall cells underlie remodelling. In addition, immune cells, including macrophages and lymphocytes, may infiltrate vessels and initiate inflammatory signalling. They contribute to a dynamic interplay between cell proliferation, apoptosis, migration, inflammation, and extracellular matrix reorganisation, all critical mechanisms of vascular remodelling. Molecular pathways underlying these processes include growth factors (e.g., vascular endothelial growth factor and platelet-derived growth factor), inflammatory cytokines (e.g., interleukin-1β and tumour necrosis factor-α), reactive oxygen species, and signalling pathways, such as Rho/ROCK, MAPK, and TGF-β/Smad, related to nitric oxide and superoxide biology. MicroRNAs and long noncoding RNAs are crucial epigenetic regulators of gene expression in vascular remodelling. We evaluate these pathways for potential therapeutic targeting from a clinical translational perspective. In summary, vascular remodelling, a coordinated modification of vascular structure and function, is crucial in cardiovascular disease pathology.

The Intersection of the Pathogenic Processes Underlying Psoriasis and the Comorbid Condition of Obesity

In the past decade, our understanding of psoriasis pathogenesis has made significant steps forward, leading to the development of multiple game-changing therapies. While psoriasis primarily affects the skin, it is increasingly recognized as a systemic disease that can have effects beyond the skin. Obesity is associated with more severe forms of psoriasis and can potentially worsen the systemic inflammation and metabolic dysfunction seen in psoriatic patients. The exact mechanisms underlying the link between these two conditions are not fully understood, but it is believed that chronic inflammation and immune dysregulation play a role. In this review, we examine the existing body of knowledge regarding the intersection of pathogenic processes responsible for psoriasis and obesity. The ability of biological therapies to reduce systemic and obesity-related inflammation in patients with psoriasis will be also discussed.

The effect of leptin gene polymorphisms (LEP rs7799039 and LEPR rs1137101) on febrile neutropenia

Background and aim

Leptin is mainly produced in adipose tissue and released into systemic circulation. Leptin and its receptor LEPR activate the Janus kinase/signal transducers and activators of transcription signaling cascade and increase cytokine discharge. In our study, we aimed to examine the role of leptin gene (LEP) rs7799039 and LEPR rs1137101 polymorphisms on the susceptibility for febrile neutropenia (FEN) attacks and their relationship with clinical findings during the course of FEN.

Methods

This study included pediatric patients with a diagnosis of malignancy who applied to the pediatric emergency department between December 2019 and June 2022 and healthy controls. The genotypes of the LEP rs7799039 and LEPR rs1137101 genes were statistically compared between patients and healthy controls. In addition, the relationship between the genotype distribution of LEP rs7799039 and LEPR rs1137101 polymorphisms and clinical features during the course of FEN was investigated.

Results

In the statistical analysis in terms of LEP rs7799039 and LEPR rs1137101 genotype distributions between the patient and healthy groups, there was no significant difference. Patients with the AA genotype of LEPR rs1137101 polymorphism had significantly more commonly a body mass index (BMI) value of <25, and all the patients with the AG/GG genotype had a BMI value of 25 and above. LEP rs7799039 and LEPR rs1137101 genotype distributions were not statistically significant with other clinical features.

Conclusions

It was revealed that leptin gene polymorphisms did not have a significant effect during the course of FEN.

Neuroprotective potential of Erigeron bonariensis ethanolic extract against ovariectomized/D-galactose-induced memory impairments in female rats in relation to its metabolite fingerprint as revealed using UPLC/MS

Erigeron bonariensis is widely distributed throughout the world's tropics and subtropics. In folk medicine, E. bonariensis has historically been used to treat head and brain diseases. Alzheimer's disease (AD) is the most widespread form of dementia initiated via disturbances in brain function. Herein, the neuroprotective effect of the chemically characterized E. bonariensis ethanolic extract is reported for the first time in an AD animal model. Chemical profiling was conducted using UPLC-ESI-MS analysis. Female rats underwent ovariectomy (OVX) followed by 42 days of D-galactose (D-Gal) administration (150 mg/kg/day, i.p) to induce AD. The OVX/D-Gal-subjected rats received either donepezil (5 mg/kg/day) or E. bonariensis at 50, 100, and 200 mg/kg/day, given 1 h prior to D-Gal. UPLC-ESI-MS analysis identified 42 chemicals, including flavonoids, phenolic acids, terpenes, and nitrogenous constituents. Several metabolites, such as isoschaftoside, casticin, velutin, pantothenic acid, xanthurenic acid, C18-sphingosine, linoleamide, and erucamide, were reported herein for the first time in Erigeron genus. Treatment with E. bonariensis extract mitigated the cognitive decline in the Morris Water Maze test and the histopathological alterations in cortical and hippocampal tissues of OVX/D-Gal-subjected rats. Moreover, E. bonariensis extract mitigated OVX/D-Gal-induced Aβ aggregation, Tau hyperphosphorylation, AChE activity, neuroinflammation (NF-κBp65, TNF-α, IL-1β), and apoptosis (Cytc, BAX). Additionally, E. bonariensis extract ameliorated AD by increasing α7-nAChRs expression, down-regulating GSK-3β and FOXO3a expression, and modulating Jak2/STAT3/NF-ĸB p65 and PI3K/AKT signaling cascades. These findings demonstrate the neuroprotective and memory-enhancing effects of E. bonariensis extract in the OVX/D-Gal rat model, highlighting its potential as a promising candidate for AD management.

Leptin/lipopolysaccharide-treated dendritic cell vaccine improved cellular immune responses in an animal model of breast cancer

PURPOSE

In dendritic cells (DCs), leptin as an immune-regulating hormone, increases the IL-12 generation whereas it reduces the IL-10 production, thus contributing to TH1 cell differentiation. Using a murine model of breast cancer (BC), we evaluated the impacts of the Leptin and/or lipopolysaccharide (LPS)-treated DC vaccine on various T-cell-related immunological markers.

MATERIALS AND METHODS

Tumors were established in mice by subcutaneously injecting 7 × 105 4T1 cells into the right flank. Mice received the DC vaccines pretreated with Leptin, LPS, and both Leptin/LPS, on days 12 and 19 following tumor induction. The animals were sacrificed on day 26 and after that the frequency of the splenic cytotoxic T lymphocytes (CTLs) and TH1 cells; interferon gamma (IFN-γ), interleukin 12 (IL-12) and tumor growth factor beta (TGF-β) generation by tumor lysate-stimulated spleen cells, and the mRNA expression of T-bet, FOXP3 and Granzyme B in the tumors were measured with flow cytometry, ELISA and real-time PCR methods, respectively.

RESULTS

Leptin/LPS-treated mDC group was more efficient in blunting tumor growth (p = .0002), increasing survival rate (p = .001), and preventing metastasis in comparison with the untreated tumor-bearing mice (UT-control). In comparison to the UT-control group, treatment with Leptin/LPS-treated mDC also significantly increased the splenic frequencies of CTLs (p < .001) and TH1 cells (p < .01); promoted the production of IFN-γ (p < .0001) and IL-12 (p < .001) by splenocytes; enhanced the T-bet (p < .05) and Granzyme B (p < .001) expression, whereas decreased the TGF-β and FOXP3 expression (p < .05).

CONCLUSION

Compared to the Leptin-treated mDC and LPS-treated mDC vaccines, the Leptin/LPS-treated mDC vaccine was more effective in inhibiting BC development and boosting immune responses against tumor.

Leptin levels in childhood tuberculosis and its correlation with body mass index, IFN-γ, and TNF-α in an Indonesian population

BACKGROUND

Leptin plays a key role in the regulation of energy and inflammation in tuberculosis (TB). However, its correlation in children with TB remains unclear. Therefore, this study aimed to evaluate the correlations between body mass index, IFN-γ, TNF-α, and leptin levels in children with TB.

METHODS

This was a cross-sectional study of children aged 2-14 years with TB. Sputum examination, chest radiography, and tuberculin skin test findings and clinical symptoms were considered for TB diagnosis. Data on body weight; height; mid-upper arm circumference (MUAC); body mass index (BMI); food intake; and IFN-γ, TNF-α, and leptin levels were collected and analyzed.

RESULTS

Of the 64 diagnosed TB subjects, 2 subjects had positive bacteriological results. The median age was 6 (2-14) years, body weight was 17.7 (9.45-55) kg, height was 114 ± 21.46 cm, and Z score BMI was -0.85 ± 1.14 kg/m2. Malnourished was observed in 17.2% of the subjects. The median calorie intake was 1448.5 (676-4674) kcal, carbohydrate intake was 182.5 (63-558) g, protein intake was 57.9 (15.8-191.0) g, and fat intake was 81.6 (23.6-594.1) g. The median leptin level was 1.2 (0.2-59) ng/mL, IFN-γ was 2.5 (0.9-161) pg/mL, and TNF-α was 13.0 (5.7-356) pg/mL. Correlations were observed between leptin and MUAC (r = 0.251, p = 0.02), Z score (r = 0.453, p = 0.00), and IFN-γ (r = 0.295, p = 0.018).

CONCLUSION

There were positive correlations between BMI and leptin levels, whereas IFN-γ and MUAC showed weak correlations.

Metabolic influences on T cell in psoriasis: a literature review

Psoriasis is a systemic inflammatory disease that frequently coexists with various other conditions, such as essential hypertension, diabetes, metabolic syndrome, and inflammatory bowel disease. The association between these diseases may be attributed to shared inflammatory pathways and abnormal immunomodulatory mechanisms. Furthermore, metabolites also play a regulatory role in the function of different immune cells involved in psoriasis pathogenesis, particularly T lymphocytes. In this review, we have summarized the current research progress on T cell metabolism in psoriasis, encompassing the regulation of metabolites in glucose metabolism, lipid metabolism, amino acid metabolism, and other pathways within T cells affected by psoriasis. We will also explore the interaction and mechanism between psoriatic metabolites and immune cells. Moreover, we further discussed the research progress of metabolomics in psoriasis to gain a deeper understanding of its pathogenesis and identify potential new therapeutic targets through identification of metabolic biomarkers associated with this condition.

Relevance and consequence of chronic inflammation for obesity development

BACKGROUND

Increasing prevalence of morbid obesity accompanied by comorbidities like type 2 diabetes mellitus (T2DM) led to a demand for improving therapeutic strategies and pharmacological intervention options. Apart from genetics, inflammation processes have been hypothesized to be of importance for the development of obesity and related aspects like insulin resistance.

MAIN TEXT

Within this review, we provide an overview of the intricate interplay between chronic inflammation of the adipose tissue and the hypothalamus and the development of obesity. Further understanding of this relationship might improve the understanding of the underlying mechanism and may be of relevance for the establishment of new treatment strategies.

Imbalance of helper T cell subtypes and adipokine secretion in perivascular adipose tissue as a trigger of atherosclerosis in chronic Porphyromonas gingivalis W83 infection

Periodontal disease, a prevalent oral disease, is an independent risk factor for atherosclerosis. Porphyromonas gingivalis (P.g), a keystone pathogen of periodontal disease, contributes to the pathogenesis of atherosclerosis. However, the exact mechanism remains unclear. An increasing number of studies have proposed the atherogenic influence of perivascular adipose tissue (PVAT) in pathological conditions including hyperlipidemia and diabetes. Nevertheless, the role of PVAT in atherosclerosis promoted by P.g infection has not been explored. In our study, we investigated the association between P.g colonization in PVAT and progression of atherosclerosis through experiments on clinical samples. We further investigated P.g invasion of PVAT, PVAT inflammation, aortic endothelial inflammation, aortic lipid deposition, and systemic inflammation in C57BL/6 J mice with or without P.g infection at 20, 24, and 28 weeks of age. PVAT inflammation, characterized by imbalance in Th1/Treg and dysregulated adipokine levels, was associated with P.g invasion, preceding endothelial inflammation that occurred independently of its direct invasion. The phenotype of systemic inflammation coincided with that of PVAT inflammation, but systemic inflammation occurred after endothelial inflammation. Therefore PVAT inflammation in early atherosclerosis could be a primary trigger of aortic endothelial inflammation and lipid deposition in chronic P.g infection, through the dysregulated paracrine secretion of T helper-1-related adipokines.

Breast feeding, obesity, and asthma association: clinical and molecular views

Asthma is a chronic condition that affects children worldwide. Accumulating number of studies reported that the prevalence of pediatric obesity and asthma might be altered through breastfeeding. It has been proposed that Leptin, which exists in human milk, is oppositely associated with weight increase in newborns. It may also influence peripheral immune system by promoting TH1 responses and suppressing TH2 cytokines. Leptin influences body weight and immune responses through complex signaling pathways at molecular level. Although previous studies provide explanations for the protective role of breastfeeding against both obesity and asthma, other factors such as duration of breastfeeding, parental, and prenatal factors may confound this relationship which requires further research.

Fat and inflammation: adipocyte-myeloid cell crosstalk in atherosclerosis

Adipose tissue inflammation has been implicated in various chronic inflammatory diseases and cancer. Perivascular adipose tissue (PVAT) surrounds the aorta as an extra layer and was suggested to contribute to atherosclerosis development. PVAT regulates the function of endothelial and vascular smooth muscle cells in the aorta and represent a reservoir for various immune cells which may participate in aortic inflammation. Recent studies demonstrate that adipocytes also express various cytokine receptors and, therefore, may directly respond to inflammatory stimuli. Here we will summarize current knowledge on immune mechanisms regulating adipocyte activation and the crosstalk between myeloid cells and adipocytes in pathogenesis of atherosclerosis.

Regulation and function of adiponectin in the intestinal epithelial cells in response to Trichinella spiralis infection

Besides metabolic homeostasis regulation, adipokines are recently emerged as important players in regulating immunity and inflammation. Helminth infection has known to modulate circulating adipokine secretion; however, the regulation and function of adipokines in response to helminth infection is still unclear. Here, we investigated the regulation and function of adiponectin during T. spiralis infection. While there was no change in circulating level of adiponectin, we found an increased adiponectin, but not leptin expression in the small intestine. Interestingly, the intestinal adiponectin expression was strongly associated with the expression of epithelial cell-derived cytokines IL-25, IL-33, and TSLP following infection. Indeed, mice deficiency of IL-25 receptor exhibited no intestinal adiponectin induction upon helminth infection. Interestingly, IL-25-induced adiponectin modulated intestinal epithelial cell responses by enhancing occludin and CCL17 expression. Using LPS-induced intestinal epithelial barrier dysfunctions in a Caco-2 cell monolayer model, adiponectin pretreatment enhanced a Transepithelial electrical resistance (TEER) and occludin expression. More importantly, adiponectin pretreatment of Caco2 cells prevented T. spiralis larval invasion in vitro and its administration during infection enhanced intestinal IL-13 secretion and worm expulsion in vivo. Altogether, our data suggest that intestinal adiponectin expression induced by helminth infection through the regulation of IL-25 promotes worm clearance and intestinal barrier function.

High tissue-sodium associates with systemic inflammation and insulin resistance in obese individuals

BACKGROUND AND AIMS

High sodium intake is associated with obesity and insulin resistance, and high extracellular sodium content may induce systemic inflammation, leading to cardiovascular disease. In this study, we aim to investigate whether high tissue sodium accumulation relates with obesity-related insulin resistance and whether the pro-inflammatory effects of excess tissue sodium accumulation may contribute to such association.

METHODS AND RESULTS

In a cross-sectional study of 30 obese and 53 non-obese subjects, we measured insulin sensitivity determined as glucose disposal rate (GDR) using hyperinsulinemic euglycemic clamp, and tissue sodium content using 23Na magnetic resonance imaging. Median age was 48 years, 68% were female and 41% were African American. Median (interquartile range) BMI was 33 (31.5, 36.3) and 25 (23.5, 27.2) kg/m2 in the obese and non-obese individuals, respectively. In obese individuals, insulin sensitivity negatively correlated with muscle (r = -0.45, p = 0.01) and skin sodium (r = -0.46, p = 0.01). In interaction analysis among obese individuals, tissue sodium had a greater effect on insulin sensitivity at higher levels of high-sensitivity C-reactive protein (p-interaction = 0.03 and 0.01 for muscle and skin Na+, respectively) and interleukin-6 (p-interaction = 0.024 and 0.003 for muscle and skin Na+, respectively). In interaction analysis of the entire cohort, the association between muscle sodium and insulin sensitivity was stronger with increasing levels of serum leptin (p-interaction = 0.01).

CONCLUSIONS

Higher muscle and skin sodium are associated with insulin resistance in obese patients. Whether high tissue sodium accumulation has a mechanistic role in the development of obesity-related insulin resistance through systemic inflammation and leptin dysregulation remains to be examined in future studies.

CLINICALTRIALS

gov registration: NCT02236520.

Leptin regulates thymic plasmacytoid dendritic cell ability to influence the thymocyte distribution in vitro

Leptin, the adipocyte-derived hormone, involved in regulating food intake and body weight, plays an important role in immunity and reproduction. Leptin signals via the specific membrane receptors expressed in most types of immune cells including dendritic cells (DCs) and thymocytes. Leptin enhances thymopoiesis and modulates T-cell-mediated immunity. Thymic plasmacytoid DCs (pDCs) are predominated in the thymus. They play an important role in thymocyte differentiation. We have analyzed whether leptin mediates its effects on human thymocytes by influencing on pDCs. We used leptin at concentration corresponding to its level during II-III trimesters of physiological pregnancy. We cultivated leptin-primed pDCs with autologous thymocytes and estimated the main thymocyte subsets expressing αβ chains of the T-cell receptor (αβTCR), natural regulatory T-cells (tTreg), natural T-helpers producing interleukin-17 (nTh17) and invariant natural killer T-cells (iNKT) in vitro. We have shown that leptin augmented CD86, CD276 expressions and depressed IL-10 productions by pDCs. Leptin-primed pDCs decreased the percentage of CD4⁺CD8⁺αβTCR⁺ thymocytes, increased CD4^hiCD8^-/loαβTCR⁺ cells. pDCs cultivated with leptin decreased the number of iNKT precursors, and did not change the number of tTreg and nTh17 precursors. Thus, leptin's important role in regulation of thymic pDC abilities to influence on the thymocyte distribution was indicated in vitro.

Crosstalk between CD4+ T Cells and Airway Smooth Muscle in Pediatric Obesity-related Asthma

Rationale: Pediatric obesity-related asthma is a nonatopic asthma phenotype with high disease burden and few effective therapies. RhoGTPase upregulation in peripheral blood T helper (Th) cells is associated with the phenotype, but the mechanisms that underlie this association are not known. Objectives: To investigate the mechanisms by which upregulation of CDC42 (Cell Division Cycle 42), a RhoGTPase, in Th cells is associated with airway smooth muscle (ASM) biology. Methods: Chemotaxis of obese asthma and healthy-weight asthma Th cells, and their adhesion to obese and healthy-weight nonasthmatic ASM, was investigated. Transcriptomics and proteomics were used to determine the differential effect of obese and healthy-weight asthma Th cell adhesion to obese or healthy-weight ASM biology. Measurements and Main Results: Chemotaxis of obese asthma Th cells with CDC42 upregulation was resistant to CDC42 inhibition. Obese asthma Th cells were more adherent to obese ASM compared with healthy-weight asthma Th cells to healthy-weight ASM. Compared with coculture with healthy-weight ASM, obese asthma Th cell coculture with obese ASM was positively enriched for genes and proteins involved in actin cytoskeleton organization, transmembrane receptor protein kinase signaling, and cell mitosis, and negatively enriched for extracellular matrix organization. Targeted gene evaluation revealed upregulation of IFNG, TNF (tumor necrosis factor), and Cluster of Differentiation 247 (CD247) among Th cell genes, and of Ak strain transforming (AKT), Ras homolog family member A (RHOA), and CD38, with downregulation of PRKCA (Protein kinase C-alpha), among smooth muscle genes. Conclusions: Obese asthma Th cells have uninhibited chemotaxis and are more adherent to obese ASM, which is associated with upregulation of genes and proteins associated with smooth muscle proliferation and reciprocal nonatopic Th cell activation.

Pediatric obesity and severe asthma: Targeting pathways driving inflammation

Asthma affects more than 300 million people of all ages worldwide, including about 10-15% of school-aged children, and its prevalence is increasing. Severe asthma (SA) is a particular and rare phenotype requiring treatment with high-dose inhaled corticosteroids plus a second controller and/or systemic glucocorticoid courses to achieve symptom control or remaining "uncontrolled" despite this therapy. In SA, other diagnoses have been excluded, and potential exacerbating factors have been addressed. Notably, obese asthmatics are at higher risk of developing SA. Obesity is both a major risk factor and a disease modifier of asthma in children and adults: two main "obese asthma" phenotypes have been described in childhood with high or low levels of Type 2 inflammation biomarkers, respectively, the former characterized by early onset and eosinophilic inflammation and the latter by neutrophilic inflammation and late-onset. Nevertheless, the interplay between obesity and asthma is far more complex and includes obese tissue-driven inflammatory pathways, mechanical factors, comorbidities, and poor response to corticosteroids. This review outlines the most recent findings on SA in obese children, particularly focusing on inflammatory pathways, which are becoming of pivotal importance in order to identify selective targets for specific treatments, such as biological agents.

Leptin Deficiency May Influence the Divergence of Cell-Mediated Immunity Between Lepromatous and Tuberculoid Leprosy Patients

Leprosy is a disease caused by an intracellular bacillus bacterium called Mycobacterium leprae which lives and multiplies in the hosts' macrophages and Schwann cells. Depending on the degree of the host's cell-mediated immunity (CMI) response to the bacilli, the disease manifests itself in five clinical spectra ranging from polar tuberculoid (TT) to polar lepromatous leprosy (LL). A very high level of T helper 1 (Th1) driven bacilli-specific CMI is seen in the TT form, whereas this response is essentially nonexistent in the LL form. As a result, there is very low or absent bacillary load and localized nodular lesions in TT patients. On the contrary, LL patients presented with high bacillary load and generalized lesions due to low CMI response. The mechanism underlying this divergence of CMI response is not clearly elucidated yet. However, mounting evidence links it to an elevated number of Th1 and Th17 suppressing CD4+ CD25+ FOXP3+ T regulatory cells (Treg cells) which are abundantly found in LL than in TT patients. The predominance of these cells in LL patients is partly attributed to a deficiency of leptin, the cytokine-like peptide hormone, in these patients. Becausea normal level of leptin promotes the proliferation and preferential differentiation of effector T cells (Th1 and Th17) while inhibiting the growth and functional responsiveness of the Treg cells. In contrast, leptin deficiency or neutralization was reported to exert the opposite effect on Treg cells and effector T cells. Other smaller subsets of lymphocytes such as gamma delta (γδ) T cells and B regulatory cells are also modulated by leptin level in the pathogenesis of leprosy. Leptin may therefore regulate the divergence of CMI between TT and LL patients by regulating the homeostasis of effector T cells and Treg cells, and this review will examine the underlying mechanism for this.

Obesity-Mediated Immune Modulation: One Step Forward, (Th)2 Steps Back

Over the past decades, the relationship between the immune system and metabolism has become a major research focus. In this arena of immunometabolism the capacity of adipose tissue to secrete immunomodulatory molecules, including adipokines, within the underlying low-grade inflammation during obesity brought attention to the impact obesity has on the immune system. Adipokines, such as leptin and adiponectin, influence T cell differentiation into different T helper subsets and their activation during immune responses. Furthermore, within the cellular milieu of adipose tissue nutrient availability regulates differentiation and activation of T cells and changes in cellular metabolic pathways. Upon activation, T cells shift from oxidative phosphorylation to oxidative glycolysis, while the differential signaling of the kinase mammalian target of rapamycin (mTOR) and the nuclear receptor PPARγ, amongst others, drive the subsequent T cell differentiation. While the mechanisms leading to a shift from the typical type 2-dominated milieu in lean people to a Th1-biased pro-inflammatory environment during obesity are the subject of extensive research, insights on its impact on peripheral Th2-dominated immune responses become more evident. In this review, we will summarize recent findings of how Th2 cells are metabolically regulated during obesity and malnutrition, and how these states affect local and systemic Th2-biased immune responses.

The Head-to-Toe Hormone: Leptin as an Extensive Modulator of Physiologic Systems

Leptin is a well-known hunger-sensing peptide hormone. The role of leptin in weight gain and metabolic homeostasis has been explored for the past two decades. In this review, we have tried to shed light upon the impact of leptin signaling on health and diseases. At low or moderate levels, this peptide hormone supports physiological roles, but at chronically higher doses exhibits detrimental effects on various systems. The untoward effects we observe with chronically higher levels of leptin are due to their receptor-mediated effect or due to leptin resistance and are not well studied. This review will help us in understanding the non-anorexic roles of leptin, including their contribution to the metabolism of various systems and inflammation. We will be able to get an alternative perspective regarding the physiological and pathological roles of this mysterious peptide hormone.

Obesity Accelerates Age Defects in Human B Cells and Induces Autoimmunity

Aging is associated with systemic inflammation and decreased production of protective antibodies while the production of autoimmune antibodies is increased. Our results have shown that the human obese adipose tissue (AT), which increases in size with aging, contributes to systemic and B cell intrinsic inflammation, reduced protective and increased pathogenic B cell responses leading to increased secretion of autoimmune antibodies. With this R56 funding, we have been able to investigate the cellular and molecular mechanisms by which the human obese AT induces intrinsic B cell inflammation and dysfunctional B cell responses, stimulates the secretion of autoimmune antibodies, whose specificity has been characterized, and engages different AT cell types in antigen presentation pathways to allow secretion of these autoimmune antibodies. Briefly, immune cells are recruited to the AT by chemokines released by both non-immune (adipocytes) and by resident and infiltrating immune cells. We have identified several mechanisms responsible for the release of "self" antigens, and we have shown that reduced oxygen availability and hypoxia, cell cytotoxicity and DNA damage induce cell death and lead to further release of pro-inflammatory cytokines, "self" protein antigens, cell-free DNA and lipids. We have also identified different antigen presenting cells in the AT, responsible for the activation of pathogenic B cells, class switch and secretion of autoimmune IgG antibodies. The experiments performed have allowed the discovery of novel mechanisms for pathogenic responses and the identification of pathways to target in order to promote better humoral immunity during aging.

Respiratory diseases and obesity: special phenotype or independent events: Review

A combination of factors, including Western European eating habits, physical inactivity and genetic predisposition, lead to a dramatic increase in adipose tissue mass. A special place is occupied by abdominal obesity, in which there is an accumulation of adipose tissue in the mesentery of the small intestine and the omentum. Developing in conditions of visceral obesity, insulin resistance, dyslipidemia and systemic inflammation are one of the key components of the pathogenesis of type 2 diabetes mellitus, cardiovascular diseases, non-alcoholic fatty liver and pancreas disease, polycystic ovary disease, some forms of cancer (breast cancer, endometrial cancer, colonic and direct intestines). At the same time, the pathogenetic role of adipose tissue is not limited to its participation in the formation of the cardiometabolic continuum and oncogenesis. The most important role of metabolically active fat in the pathogenesis of many respiratory diseases is known, including bronchial asthma, obstructive sleep apnea and pulmonary hypertension. This paper presents an overview of current data on immunological, pathophysiological and clinical features of the phenotype of the combination of respiratory diseases with overweight and obesity.

The Complex Relationship Between Microbiota, Immune Response and Creeping Fat in Crohn's Disease

In the last decade, there has been growing interest in the pathological involvement of hypertrophic mesenteric fat attached to the serosa of the inflamed intestinal segments involved in Crohn's disease [CD], known as creeping fat. In spite of its protective nature, creeping fat harbours an aberrant inflammatory activity which, in an already inflamed intestine, may explain why creeping fat is associated with a greater severity of CD. The transmural inflammation of CD facilitates the interaction of mesenteric fat with translocated intestinal microorganisms, contributing to activation of the immune response. This may be not the only way in which microorganisms alter the homeostasis of this fatty tissue: intestinal dysbiosis may also impair xenobiotic metabolism. All these CD-related alterations have a functional impact on nuclear receptors such as the farnesoid X receptor or the peroxisome proliferator-activated receptor γ, which are implicated in regulation of the immune response, adipogenesis and the maintenance of barrier function, as well as on creeping fat production of inflammatory-associated cells such as adipokines. The dysfunction of creeping fat worsens the inflammatory course of CD and may favour intestinal fibrosis and fistulizing complications. However, our current knowledge of the pathophysiology and pathogenic role of creeping fat is controversial and a better understanding might provide new therapeutic targets for CD. Here we aim to review and update the key cellular and molecular alterations involved in this inflammatory process that link the pathological components of CD with the development of creeping fat.

Leptin in Dental Pulp and Periapical Tissues: A Narrative Review

Leptin is a non-glycosylated 16 kDa protein synthesized mainly in adipose cells. The main function of leptin is to regulate energy homeostasis and weight control in a central manner. There is increasing evidence that leptin also has systemic effects, acting as a link between innate and acquired immune responses. The expression of leptin and its receptor in human dental pulp and periradicular tissues have already been described, as well as several stimulatory effects of leptin protein expression in dental and periodontal tissues. The aim of this paper was to review and to compile the reported scientific literature on the role and effects of leptin in the dental pulp and periapical tissues. Twelve articles accomplished the inclusion criteria, and a comprehensive narrative review was carried out. Review of the available scientific literature concluded that leptin has the following effects on pulpal and periapical physiology: 1) Stimulates odontogenic differentiation of dental pulp stem cells (DPSCs), 2) Increases the expression of dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (DMP-1), odontoblastic proteins involved in odontoblastic differentiation and dentin mineralization, 3) Stimulates vascular endothelial growth factor (VEGF) expression in human dental pulp tissue and primary cultured cells of human dental pulp (hDPCs), 4) Stimulates angiogenesis in rat dental pulp cells, and 5) Induces the expression of interleucinas 6 and 8 in human periodontal ligament cells (hPDLCs). There is evidence which suggests that leptin is implicated in the dentin mineralization process and in pulpal and periapical inflammatory and reparative responses.

Leptin Promotes Greater Ki67 Expression in CD4+ T Cells From Obese Compared to Lean Persons Living With HIV

While antiretroviral therapy (ART) has proven effective in suppressing viremia and disease progression among people living with human immunodeficiency virus (HIV; PLWH), suboptimal CD4+ T cell reconstitution remains a major obstacle in nearly 30% of ART-treated individuals. Epidemiological studies demonstrate that obesity, or a body mass index (BMI) ≥ 30 kg/m2, is positively correlated with greater CD4+ T cell recovery in PLWH on ART. Leptin is a known immunomodulator that is produced in proportion to fat mass and is increased in obese individuals, including PLWH. We hypothesized that CD4+ T cells from obese PLWH have increased cell proliferation and cytokine production compared to cells from lean PLWH, potentially modulated by differential effects of leptin signaling. To test this hypothesis, peripheral blood mononuclear cells from obese and lean PLWH with long-term virologic suppression on the same ART regimen were pretreated with recombinant leptin and then stimulated with anti-CD3/CD28 or PMA/ionomycin to measure Ki67 expression, leptin receptor (LepR) surface expression and cytokine production. In the absence of leptin, Ki67 expression and IL-17A production were significantly higher in CD4+ T cells from obese compared to lean PLWH. However, LepR expression was significantly lower on CD4+ T cells from obese compared to lean PLWH. After leptin treatment, Ki67 expression was significantly increased in CD4+ T cells from obese PLWH compared to the lean participants. Leptin also increased IL-17A production in CD4+ T cells from obese healthy controls. In contrast, leptin decreased IL-17A production in CD4+ T cells from both obese and lean PLWH. Combined, these results demonstrate that obesity is associated with greater CD4+ T cell proliferation among PLWH, and that higher circulating leptin levels in obesity may contribute to improved CD4+ T reconstitution in PLWH initiating ART.

Circulating Mir-140 and leptin improve the accuracy of the differential diagnosis between psoriatic arthritis and rheumatoid arthritis: a case-control study

The differential diagnosis of psoriatic arthritis (PsA) and rheumatoid arthritis (RA) is difficult because of the lack of diagnostic clinical signs and reliable biomarkers. This study investigated microRNAs (miRNA) and adipokines as potential additional markers to discriminate PsA from RA. The expression profile of miRNA (miR-21, miR-140, miR-146a, miR-155, miR-181b, miR-223, miR-let-7e) and inflammatory cytokines (IL-1β, IL-6, IL-17a, IL-23a, TNF-α) from peripheral blood mononuclear cells of PsA and RA patients compared to healthy controls (HC) were evaluated by real-time PCR, and serum adipokines (adiponectin, chemerin, leptin, resistin, visfatin) and cytokines by ELISA assay. Univariable binary logistic regression was used to find the association between PsA and potential predictors. The gene expression of miRNA and cytokines and the serum levels of adipokines were found significantly different in PsA and RA patients compared to HC, as well as in PsA versus RA. MiR-140 gene expression resulted up-regulated in PsA patients and reduced in RA in comparison to HC, and, for the first time, significantly higher in PsA compared with RA. Serum levels of IL-23a and leptin were significantly increased in PsA and RA populations than in HC, as well as in PsA versus RA. Furthermore, circulating TNF-α was up-regulated in PsA and RA in comparison to controls, while resulted higher in RA than in PsA. Univariable binary logistic regression analysis found the above-mentioned markers associated to PsA versus RA. Our results first demonstrated an increased expression of circulating miR-140 and serum leptin in PsA patients compared to RA, which were identified as potential additional biomarkers to discriminate PsA from RA. Since the differential diagnosis of PsA and RA poses challenges in clinical practice, our data may help to enhance the diagnostic performance of PsA in daily practice.

Inflammatory arthritis increases the susceptibility to acute immune-mediated hepatitis in mice through enhancing leptin expression in T cells

Liver function abnormalities are common in patients with inflammatory arthritis. However, the precise mechanism is still unclear. In this study, inflammatory arthritis was established in mice by subcutaneous injection of complete Freund's adjuvant, and the intravenous injection of concanavalin A (Con A) was employed to induce acute immune-mediated hepatitis in mice. The result showed that the arthritis mice were more susceptible to ConA-induced hepatitis than the control mice, as evidenced by increased hepatic necrosis, elevated serum alanine aminotransferase activity, and raised inflammatory cytokines. Besides, the in vitro assay demonstrated that the T cells from arthritis mice were more sensitive to the Con A stimulation than those from control mice. Moreover, we determined that the level of leptin, a kind of adipokine, was significantly increased in the serum and hepatic T cells of arthritis mice. Interestingly, the data indicated that the enhanced expression of leptin in hepatic T cells is responsible for the hypersensitivity of arthritis mice-derived T cells to Con A challenge. Collectively, our findings demonstrate an unexpected role of leptin in the connection between inflammatory arthritis and acute immune-mediated hepatitis, thus providing new insight into the clinical therapy of arthritis-related liver dysfunction.

A Tale of Three Systems: Toward a Neuroimmunoendocrine Model of Obesity

The prevalence of obesity is on the rise. What was once considered a simple disease of energy imbalance is now recognized as a complex condition perpetuated by neuro- and immunopathologies. In this review, we summarize the current knowledge of the neuroimmunoendocrine mechanisms underlying obesity. We examine the pleiotropic effects of leptin action in addition to its established role in the modulation of appetite, and we discuss the neural circuitry mediating leptin action and how this is altered with obesity, both centrally (leptin resistance) and in adipose tissues (sympathetic neuropathy). Finally, we dissect the numerous causal and consequential roles of adipose tissue macrophages in obesity and highlight recent key studies demonstrating their direct role in organismal energy homeostasis.

Metabolic syndrome and hidradenitis suppurativa: epidemiological, molecular, and therapeutic aspects

Hidradenitis suppurativa (HS) is a chronic, suppurative condition of the pilosebaceous unit. Patients suffering from HS demonstrate a molecular profile in keeping with a state of systemic inflammation and are often found to fit the criteria for a diagnosis of metabolic syndrome (MetS). In this paper, we review the literature with regards to established data on the prevalence of MetS in HS patients and revise the odds ratio of comorbid disease. Furthermore, we attempt to draw parallels between inflammatory pathways in HS and MetS and evaluate how convergences may explain the risk of comorbid disease, necessitating the need for multidisciplinary care.

Influence of Obesity on Clinical Manifestations and Response to Therapy in Cutaneous Leishmaniasis Caused by Leishmania braziliensis

BACKGROUND

Cutaneous leishmaniasis (CL) caused by Leishmania braziliensis is characterized by a single ulcer or multiple cutaneous lesions with raised borders. Cure rates <60% are observed in response to meglumine antimoniate therapy. We investigated the impact of obesity on CL clinical presentation and therapeutic response.

METHODS

A total of 90 age-matched patients with CL were included (30 obese, 30 overweight, and 30 with normal body mass index [BMI]). CL was diagnosed through documentation of L. braziliensis DNA by polymerase chain reaction or identification of amastigotes in biopsied skin-lesion samples. Serum cytokine levels were determined by chemiluminescence. Antimony therapy with Glucantime (Sanofi-Aventis; 20 mg/kg/day) was administered for 20 days.

RESULTS

Obese CL patients may present hypertrophic ulcers rather than typical oval, ulcerated lesions. A direct correlation between BMI and healing time was noted. After 1 course of antimony, cure was achieved in 73% of patients with normal BMI, 37% of overweight subjects, yet just 18% of obese CL patients (P < .01). Obese CL cases additionally presented higher leptin levels than overweight patients or those with normal BMI (P < .05).

CONCLUSIONS

Obesity modifies the clinical presentation of CL and host immune response and is associated with greater failure to therapy.

Emerging role of leptin in joint inflammation and destruction

Rheumatoid arthritis (RA) is an autoimmune disease characterized by tumor-like hyperplasia and inflammation of the synovium, which causes synovial cell invasion into the bone and cartilage. In RA pathogenesis, various molecules in effector cells (i.e., immune cells and mesenchymal cells) are dysregulated by genetic and environmental factors. Consistent with the early stages of RA, these pathogenic cells cooperate and activate each other directly by cell-to-cell contact or indirectly via humoral factors. Recently, growing evidence has revealed essential role of adipokines, which are multifunctional signal transduction molecules, in the immune system. In this review, we summarize the current understanding of the cross-talk between leptin, one of the most well-known and best-characterized adipokines, and osteoimmunology. Furthermore, we discuss the contribution of leptin to the pathogenesis of RA and its potential mechanisms.

Adipose Tissue Immunomodulation and Treg/Th17 Imbalance in the Impaired Glucose Metabolism of Children with Obesity

In the last few decades, obesity has increased dramatically in pediatric patients. Obesity is a chronic disease correlated with systemic inflammation, characterized by the presence of CD4 and CD8 T cell infiltration and modified immune response, which contributes to the development of obesity related diseases and metabolic disorders, including impaired glucose metabolism. In particular, Treg and Th17 cells are dynamically balanced under healthy conditions, but imbalance occurs in inflammatory and pathological states, such as obesity. Some studies demonstrated that peripheral Treg and Th17 cells exhibit increased imbalance with worsening of glucose metabolic dysfunction, already in children with obesity. In this review, we considered the role of adipose tissue immunomodulation and the potential role played by Treg/T17 imbalance on the impaired glucose metabolism in pediatric obesity. In the patient care, immune monitoring could play an important role to define preventive strategies of pediatric metabolic disease treatments.

Leptin, Both Bad and Good Actor in Cancer

Leptin is an important regulator of basal metabolism and food intake, with a pivotal role in obesity. Leptin exerts many different actions on various tissues and systems, including cancer, and is considered as a linkage between metabolism and the immune system. During the last decades, obesity and leptin have been associated with the initiation, proliferation and progression of many types of cancer. Obesity is also linked with complications and mortality, irrespective of the therapy used, affecting clinical outcomes. However, some evidence has suggested its beneficial role, called the "obesity paradox", and the possible antitumoral role of leptin. Recent data regarding the immunotherapy of cancer have revealed that overweight leads to a more effective response and leptin may probably be involved in this beneficial process. Since leptin is a positive modulator of both the innate and the adaptive immune system, it may contribute to the increased immune response stimulated by immunotherapy in cancer patients and may be proposed as a good actor in cancer. Our purpose is to review this dual role of leptin in cancer, as well as trying to clarify the future perspectives of this adipokine, which further highlights its importance as a cornerstone of the immunometabolism in oncology.

The Postnatal Leptin Surge Supports Immune Cell Function in Rats

Background: Leptin plays an important role in the regulation of the immune response. There is a physiological surge of leptin in rodents during the neonatal period, which has mainly been studied in the context of brain development. However, little is known about the effects of this neonatal leptin surge on immunity. Therefore, we investigated whether blocking this leptin surge could affect several immune functions.Methods: Male and female rats were injected subcutaneously with 5 mg/Kg/day of rat pegylated super leptin antagonist during the neonatal period (PND5-9). On the peripubertal period, relevant functions as well as cytokine release by spleen leukocytes were studied in these animals.Results: The results showed that the animals significantly display an impaired anti-tumor NK activity and chemotactic and proliferation capacity of lymphocytes in response to mitogens. In addition, several cytokine concentrations, released under mitogen-stimulated conditions, were also altered.Conclusion: In conclusion, the neonatal leptin surge seems to be involved in the establishment of an adequate immune response and cytokine profile, which are crucial for the maintenance of a healthy life.

Circulating leptin, soluble leptin receptor and free leptin index in critically ill patients with sepsis: a prospective observational study

BACKGROUND

Leptin, the prototype adipokine, exerts immunomodulatory actions being implicated in inflammatory responses during sepsis. Clinical evidence regarding its role in sepsis has been contradictory, while free leptin has not been studied. Our aim was to jointly investigate circulating total leptin, its soluble receptor (sOBR), and free leptin, as well as their kinetics in critically ill patients with sepsis regarding their diagnostic and prognostic value.

METHODS

In a prospective study, serum total leptin, sOBR and free leptin index (FLI) were determined in 102 critically ill patients with sepsis within 48 hours from sepsis onset and one week after enrollment, and in 102 age and gender-matched healthy controls.

RESULTS

Upon enrollment, total leptin, sOB-R and FLI were significantly higher in septic patients compared to controls and they were positively correlated with sepsis severity scores, while they presented a significant decrease during the first week (p<0.001). The decrease in total leptin and sOB-R was significantly higher in patients with sepsis compared to septic shock and in survivors compared to nonsurvivors at 28 days (p<0.001). Higher serum total leptin was independently associated with survival at 28 days (enrollment: HR 0.86, p=0.03; one week after: HR 0.77, p<0.001). Higher kinetics of total leptin (but not FLI) was independently associated with survival after adjustment (HR: 0.48, p=0.001).

CONCLUSIONS

Higher circulating total leptin and its higher kinetics during the first week from sepsis onset independently predict 28 day survival in critically ill patients. Free leptin did not present any additional diagnostic and prognostic value in sepsis.

Undernutrition and HIV Infection in Sub-Saharan Africa: Health Outcomes and Therapeutic Interventions

PURPOSE OF REVIEW

Sub-Saharan Africa (SSA) is disproportionately burdened by the twin epidemics of food insecurity and HIV infection, and protein-calorie undernutrition is common among persons with HIV (PWH) initiating antiretroviral therapy (ART) in the region. In this review, we discuss the intersection of HIV infection and undernutrition, health outcomes among undernourished PWH starting ART, and the demonstrated and potential benefits of therapeutic interventions such as micro/macronutrient supplementation and pharmacological agents.

RECENT FINDINGS

A low body mass index (BMI), used as a general indicator of poor nutrition in most studies, is associated with impaired immune recovery and increased mortality in the early ART period. The increased risk of mortality is multifactorial, and contributors include undernutrition-related immune system dysfunction, increased susceptibility to opportunistic infections, and metabolic and cardiovascular dysregulation. Clinical trials of micro/macronutrient supplementary feeding, appetite stimulants (hormones and anabolic agents), and recombinant adipokines have shown a benefit for weight gain and metabolic health, but there are few data on mortality or immune recovery. A substantial proportion of PWH in SSA are undernourished, and undernutrition contributes to an increased risk of mortality and other adverse health outcomes. To date, there have been few prospective trials of nutritional supplementation and/or pharmacologic therapy among undernourished PWH in SSA, though findings from other settings suggest a potential benefit in this population.

The role of immune dysfunction in obesity-associated cancer risk, progression, and metastasis

Obesity has been linked to an increased risk of and a worse prognosis for several types of cancer. A number of interrelated mediators contribute to obesity's pro-tumor effects, including chronic adipose inflammation and other perturbations of immune cell development and function. Here, we review studies examining the impact of obesity-induced immune dysfunction on cancer risk and progression. While the role of adipose tissue inflammation in obesity-associated cancer risk has been well characterized, the effects of obesity on immune cell infiltration and activity within the tumor microenvironment are not well studied. In this review, we aim to highlight the impact of both adipose-mediated inflammatory signaling and intratumoral immunosuppressive signaling in obesity-induced cancer risk, progression, and metastasis.

The complex role of adipokines in obesity, inflammation, and autoimmunity

The global obesity epidemic is a major contributor to chronic disease and disability in the world today. Since the discovery of leptin in 1994, a multitude of studies have characterized the pathological changes that occur within adipose tissue in the obese state. One significant change is the dysregulation of adipokine production. Adipokines are an indispensable link between metabolism and optimal immune system function; however, their dysregulation in obesity contributes to chronic low-grade inflammation and disease pathology. Herein, I will highlight current knowledge on adipokine structure and physiological function, and focus on the known roles of these factors in the modulation of the immune response. I will also discuss adipokines in rheumatic and autoimmune diseases.

Adipokines and Chronic Rheumatic Diseases: from Inflammation to Bone Involvement

Besides its well-known role as energy storage tissue, adipose tissue is a biologically active tissue that can also be considered as an endocrine organ, as it is able to secrete adipokines. These bioactive factors, similar in structure to cytokines, are involved in several physiological and pathological conditions, such as glucose homeostasis, angiogenesis, blood pressure regulation, control of food intake, and also inflammation and bone homeostasis via endocrine, paracrine, and autocrine mechanisms. Given their pleiotropic functions, the role of adipokines has been evaluated in chronic rheumatic osteoarticular inflammatory diseases, particularly focusing on their effects on inflammatory and immune response and on bone alterations. Indeed, these diseases are characterized by different bone complications, such as local and systemic bone loss and new bone formation. The aim of this review is to summarize the role of adipokines in rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, osteoarthritis, and osteoporosis, especially considering their role in the pathogenesis of bone complications typical of these conditions.

An Update on the Role of Leptin in the Immuno-Metabolism of Cartilage

Since its discovery in 1994, leptin has been considered as an adipokine with pleiotropic effects. In this review, we summarize the actual information about the impact of this hormone on cartilage metabolism and pathology. Leptin signalling depends on the interaction with leptin receptor LEPR, being the long isoform of the receptor (LEPRb) the one with more efficient intracellular signalling. Chondrocytes express the long isoform of the leptin receptor and in these cells, leptin signalling, alone or in combination with other molecules, induces the expression of pro-inflammatory molecules and cartilage degenerative enzymes. Leptin has been shown to increase the proliferation and activation of immune cells, increasing the severity of immune degenerative cartilage diseases. Leptin expression in serum and synovial fluid are related to degenerative diseases such as osteoarthritis (OA), rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Inhibition of leptin signalling showed to have protective effects in these diseases showing the key role of leptin in cartilage degeneration.