leptin and Arthritis

During aging, body adiposity increases with changes in the metabolism of lipids and their metabolite levels. Considering lipid metabolism, excess adiposity with increased lipotoxicity leads to various age-related diseases, including cardiovascular disease, cancer, arthritis, type 2 diabetes, and Alzheimer's disease. However, the multifaceted nature and complexities of lipid metabolism make it difficult to delineate its exact mechanism and role during aging. With advances in genetic engineering techniques, recent studies have demonstrated that changes in lipid metabolism are associated with aging and age-related diseases. Lipid accumulation and impaired fatty acid utilization in organs are associated with pathophysiological phenotypes of aging. Changes in adipokine levels contribute to aging by modulating changes in systemic metabolism and inflammation. Advances in lipidomic techniques have identified changes in lipid profiles that are associated with aging. Although it remains unclear how lipid metabolism is regulated during aging, or how lipid metabolites impact aging, evidence suggests a dynamic role for lipid metabolism and its metabolites as active participants of signaling pathways and regulators of gene expression. This review describes recent advances in our understanding of lipid metabolism in aging, including established findings and recent approaches.

Topics: Adiponectin; Adipose Tissue; Adiposity; Aging; Alzheimer Disease; Arthritis; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Fatty Acids; Gene Expression Regulation; Humans; Leptin; Lipid Metabolism; Lipidomics; Neoplasms; Obesity; Signal Transduction

Topics: Arthritis; Humans; Leptin; Receptors, Leptin

The roles of serum leptin in knee joint inflammation are unclear. The objective of this study was to identify any associations of serum leptin level with intra-articular inflammatory cytokine levels in acute arthritic and nonarthritic knees of mice.. Acute arthritis was induced by intra-articular injection of 2% carrageenan. Three groups (leptin-deficient ob/ob, wild-type (WT) and high-fat diet (HFD)-fed WT) were made. Serum leptin and inflammatory cytokines in the infrapatellar fat pad and synovium were measured before and 24 hr after injection. Affected knee joints were excised for histology 24 hr after injection.. The HFD-WT group had significantly higher serum leptin than the ob/ob and WT groups before and after carrageenan injection. The HFD-WT group had significantly higher IL-1? and IL-6 in the infrapatellar fat pad and synovium than ob/ob and WT before injection but significantly lower IL-1?, IL-6 and TNF-? than the ob/ob group at 24 hr.. Hyperleptinemia induced by a HFD is involved in low-grade intra-articular inflammation in nonarthritic knee joints. In contrast, leptin deficiency causes excessive intra-articular inflammation in carrageenan-induced acute arthritis. Leptin alleviates acute arthritis, while chronic hyperleptinemia is involved in low-grade inflammation in normal knee joints. J. Med. Invest. 70 : 54-59, February, 2023.

Topics: Animals; Arthritis; Carrageenan; Cytokines; Inflammation; Interleukin-1; Interleukin-6; Leptin; Mice; Mice, Inbred C57BL

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.

Topics: Acute Disease; Animals; Arthritis; Concanavalin A; Cytokines; Disease Susceptibility; Hepatitis; Hypersensitivity; Inflammation; Inflammation Mediators; Leptin; Liver; Lymphocyte Activation; Mice, Inbred C57BL; Signal Transduction; T-Lymphocytes

Authors discuss the musculoskeletal aspects of obesity by applying a novel approach. Biochemical changes associated with obesity and especially metabolic syndrome, may have a great impact on the function of bones, joints and muscles. Therefore we need a new view and new strategies in rheumatic diseases. Obesity-associated metabolic changes should be considered during the progress of as well as the selection of treatment in inflammatory rheumatic diseases. Individualised treatment is necessary due to associated comorbidities as well. Orv Hetil. 2019; 160(44): 1727-1734.. Absztrakt: A szerzők az elhízás mozgásszervi vonatkozásait új megközelítésben, elsősorban annak metabolikus hatásait kiemelve ismertetik. Az elhízással és különösen a metabolikus szindrómával járó biokémiai változások megváltoztatják a csont, az ízületi struktúrák és az izomzat működését. Ezek alapján szemléletváltozás szükséges bizonyos kórképekben az eddig kialakult nézetekben. A gyulladásos reumatológiai betegségek lefolyásának súlyosságában és az alkalmazott kezelések megválasztásában is figyelembe kell venni az elhízással járó anyagcsere-változásokat. A társuló komorbiditások miatt a személyre szabott kezelés fontossága kiemelt jelentőségű. Orv Hetil. 2019; 160(44): 1727–1734.

Topics: Adipokines; Arthritis; Humans; Joint Diseases; Leptin; Metabolic Syndrome; Musculoskeletal Diseases; Obesity; Osteoarthritis; Rheumatic Diseases

We explored the relationship of obesity and inflammatory arthritis (IA) by selectively expressing diphtheria toxin in adipose tissue yielding "fat-free" (FF) mice completely lacking white and brown fat. FF mice exhibit systemic neutrophilia and elevated serum acute phase proteins suggesting a predisposition to severe IA. Surprisingly, FF mice are resistant to K/BxN serum-induced IA and attendant bone destruction. Despite robust systemic basal neutrophilia, neutrophil infiltration into joints of FF mice does not occur when challenged with K/BxN serum. Absence of adiponectin, leptin, or both has no effect on joint disease, but deletion of the adipokine adipsin (complement factor D) completely prevents serum-induced IA. Confirming that fat-expressed adipsin modulates the disorder, transplantation of wild-type (WT) adipose tissue into FF mice restores susceptibility to IA, whereas recipients of adipsin-deficient fat remain resistant. Thus, adipose tissue regulates development of IA through a pathway in which adipocytes modify neutrophil responses in distant tissues by producing adipsin.

Topics: Adipocytes; Adipose Tissue; Animals; Arthritis; Complement Factor D; Inflammation; Leptin; Male; Mice; Mice, Inbred C57BL; Mice, Inbred NOD; Mice, Knockout; Neutrophil Infiltration; Neutrophils

Acute inflammation is a normal response of tissue to an injury. During this process, inflammatory mediators are produced and metabolic alterations occur. Adipose tissue is metabolically activated, and upon food consumption, it disrupts the inflammatory response. However, little is known about the acute inflammatory response in joints that results from diet-induced adipose tissue remodeling. The objective of this study was to determine whether alterations in adipose tissue mass arising from food consumption modify the inflammatory response of antigen-induced joint inflammation in mice.. Male BALB/c mice were fed a chow diet, a highly refined carbohydrate-containing (HC) diet for 8 wk. They were then immunized and, after 2 wk, received a knee injection of methylated bovine serum albumin (mBSA). They were sacrificed at 6, 24, and 48 h after injection. The effect of the cafeteria diet for 8 wk, which also increases adipose tissue, or conjugated linoleic acid (CLA) supplementation for 4 wk, a model of lipodystrophy, was evaluated 24 h after knee challenge with mBSA.. Cellular influx, predominantly neutrophils, in synovial fluid was attenuated in the HC diet group, as were levels of myeloperoxidase and IL-1β in periarticular tissue and histopathological analysis. These responses were associated with reduced adiponectin and increased leptin in serum, which was pronounced in mice fed the HC diet. Cafeteria diet and CLA supplementation induced a profile similar to that seen with the HC diet in terms of inflammation, disease response, and metabolic alteration. Interestingly, after the injection of mBSA, the area of adipocytes in the infrapatellar fat pad increased in mice fed with chow diet similar to those fed the HC and cafeteria diet.. We demonstrated that attenuation of joint response induced by diet was independent of adipose tissue remodeling but could be associated with metabolic alterations.

Topics: Adipocytes; Adiponectin; Adipose Tissue; Adiposity; Animals; Arthritis; Diet; Dietary Carbohydrates; Dietary Fats; Dietary Supplements; Inflammation; Interleukin-1beta; Knee Joint; Leptin; Linoleic Acids, Conjugated; Lipid Metabolism; Lipodystrophy; Male; Metabolome; Mice, Inbred BALB C; Neutrophils; Obesity; Peroxidase; Serum Albumin, Bovine

To investigate how inflammation and metabolic syndrome (MetS) are associated with adipokine levels in patients with inflammatory arthritis.. Fifty-four female patients with arthritis were enrolled in the study. Twenty (37%) of these patients had MetS, which was diagnosed according to the definition of the International Diabetes Federation (IDF). Interleukin (IL)-6 and four adipokines (resistin, leptin, adiponectin, and adipsin) were determined by immunoassay. Healthy women with body mass index (BMI) between 22 and 25 kg/m(2) served as controls.. The patients with arthritis had higher levels of resistin than the healthy controls. This difference was clear in patients without MetS (17.4 in patients vs. 10.8 ng/mL in controls, p < 0.001), and even higher resistin levels were found in the patients with MetS (20.7 ng/mL; p < 0.001 vs. healthy controls; and p = 0.095 vs. patients without MetS). In the patients with arthritis and MetS, resistin correlated positively with IL-6 (Pearson's r = 0.5, p = 0.03). Leptin levels were increased in arthritis patients with MetS as compared to healthy controls, but not in patients without MetS. The statistically significant difference between patients with MetS and controls remained when leptin was adjusted with BMI. Accordingly, adiponectin levels were lower in patients with MetS than in healthy controls (p < 0.05). Leptin, adiponectin, and adipsin did not correlate with the inflammatory cytokine IL-6 or with C-reactive protein (CRP).. The results show that high resistin levels are associated with arthritis independently of MetS, whereas leptin is increased only in arthritis patients with MetS.

Topics: Adiponectin; Adult; Arthritis; Biomarkers; Body Mass Index; C-Reactive Protein; Case-Control Studies; Comorbidity; Complement Factor D; Female; Humans; Inflammation; Leptin; Metabolic Syndrome; Middle Aged; Resistin

Elevated serum leptin levels have been described in patients with systemic lupus erythematosus (SLE), however these studies have provided no information regarding the ghrelin levels. We investigated the clinical significance of serum leptin and ghrelin levels in SLE. The leptin levels of SLE patients were higher than those of normal healthy controls, while the ghrelin levels of the SLE were lower. In addition, the ghrelin levels were significantly lower in SLE patients with arthritis and hematologic disorder. Taken together, these findings suggest that leptin and ghrelin play a role in clinical manifestations observed in SLE.

Topics: Adult; Arthritis; Asian People; Case-Control Studies; Female; Ghrelin; Hematologic Diseases; Humans; Korea; Leptin; Lupus Erythematosus, Systemic; Male; Prospective Studies; Young Adult

We studied the effect of food restriction, overfeeding, and normofeeding on cachexia, inflammatory and metabolic parameters, and insulin sensitivity in chronic adjuvant arthritis (AA) in rats. Food restriction during AA increased circulating ghrelin, corticosterone, decreased leptin, and ameliorated arthrogram score and systemic inflammation compared to normofeeding. Overfeeding worsened arthrogram score and systemic inflammation, and led to lipid accumulation in the liver, but not to alterations of adipokine and ghrelin plasma levels relative to normofeeding. Independently of feeding status, AA induced cachexia, in which modulation of mRNA expressions for appetite-regulating neuropeptides (NPY, AgRP, POMC, CART) in the arcuate nucleus (ARC) does not play a primary role. The overexpression of IL-1β mRNA in the ARC suggests its role in the mechanisms of impaired energy balance during AA under all feeding conditions. Normal HOMA index in all arthritic groups does not indicate the development of insulin resistance by feeding interventions in these rats.

Topics: Adipokines; Adrenal Cortex Hormones; Animal Feed; Animals; Arcuate Nucleus of Hypothalamus; Arthritis; Cachexia; Chemotherapy, Adjuvant; Ghrelin; Inflammation; Insulin; Leptin; Male; Neuropeptides; Rats; Rats, Inbred Lew

Food intake is activated by hypothalamic orexigenic neuropeptide Y (NPY), which is mainly under the dual control of leptin and ghrelin. Rat adjuvant arthritis (AA), similarly as human rheumatoid arthritis, is associated with cachexia caused by yet unknown mechanisms. The aim of our study was to evaluate NPY expression in hypothalamic arcuate nuclei (nARC) under the conditions of AA-induced changes in leptin, ghrelin and adiponectin. Since IL-1beta is involved in the central induction of anorexia, we studied its expression in the nARC as well.. AA was induced to Lewis rats using complete Freund's adjuvant. On days 12, 15 and 18 after complete Freund's adjuvant injection, the levels of leptin, adiponectin, ghrelin and IL-1beta were determined by RIA or ELISA. The mRNA expressions for NPY, leptin receptor (OB-R), ghrelin receptor (Ghsr) and IL-1beta were determined by TaqMan RT-PCR from isolated nARC.. In AA rats, decreased appetite, body mass and epididymal fat stores positively correlated with reduced circulating and epididymal fat leptin and adiponectin. Ghrelin plasma levels were increased. In nARC, mRNA for OB-R, Ghsr and NPY were overexpressed in AA rats. AA rats showed overexpression of mRNA for IL-1beta in nARC while circulating, and spleen IL-1beta was unaltered.. During AA, overexpression of orexigenic NPY mRNA in nARC along with enhanced plasma ghrelin and lowered leptin levels occur. Decreased food intake indicates a predominant effect of the anorexigenic pathway. Activated expression of IL-1beta in nARC suggests its role in keeping AA-induced anorexia in progress. The reduction in adiponectin may also contribute to AA-induced anorexia.

Topics: Adiponectin; Animals; Anorexia; Appetite; Appetite Regulation; Arcuate Nucleus of Hypothalamus; Arthritis; Disease Models, Animal; Gene Expression Regulation; Ghrelin; Hypothalamo-Hypophyseal System; Interleukin-1beta; Leptin; Male; Neuropeptide Y; Rats; Rats, Inbred Lew; RNA, Messenger; Signal Transduction; Up-Regulation

Leptin, a 16-kD protein of the ob gene product, is produced by adipose tissue and acts on the hypothalamus to suppress neuropeptide Y secretion which reduces the appetite. It has been demonstrated that serum leptin levels in healthy subjects are correlated with body mass index(BMI). Leptin is also produced by stimulation of inflammatory cytokines such as tumor necrosis factor(TNF)-alpha and interleukin(IL)-1. Rheumatoid arthritis(RA) is one of the chronic inflammatory diseases in which high serum cytokine levels are noted. In this study, we measured serum leptin levels(s-leptin) by RIA kit in 20 healthy subjects (10 males and 10 females) and 49 RA patients(14 males and 35 females) and the markers for joint inflammation such as ESR and CRP. There was no difference in s-leptin between controls(male: mean +/- SD = 5.6 +/- 3.0 ng/ml; female: 7.8 +/- 4.5 ng/ml) and RA patients(male: 4.9 +/- 3.2 ng/ml; female: 9.1 +/- 5.7 ng/ml). S-leptin was correlated with BMI in both healthy subjects and RA patients. However, there was no correlation between s-leptin and the values of ESR or CRP, disease stages in RA patients. In conclusion, s-leptin in RA patients reflects BMI but not joint inflammation.

Topics: Adult; Arthritis; Arthritis, Rheumatoid; Body Mass Index; Female; Humans; Leptin; Male; Middle Aged