Serum Leptin levels in Rheumatoid arthritis and relationship with disease activity

Adipokines as potential pharmacological targets for immune inflammatory rheumatic diseases: Focus on rheumatoid arthritis, osteoarthritis, and intervertebral disc degeneration

Adipokines are a heterogeneous group of signalling molecules secreted prevalently by adipose tissue. Initially considered as regulators of energy metabolism and appetite, adipokines have been recognized for their substantial involvement in musculoskeletal disorders, including osteoarthritis, rheumatoid arthritis, and many others. Understanding the role of adipokines in rheumatic inflammatory and autoimmune diseases, as well as in other musculoskeletal diseases such as intervertebral disc degeneration, is crucial for the development of novel therapeutic strategies. Targeting adipokines, or their signalling pathways, may offer new opportunities for the treatment and management of these conditions. By modulating adipokines levels or activity, it may be possible to regulate inflammation, to maintain bone health, and preserve muscle mass, thereby improving the outcomes and quality of life for individuals affected by musculoskeletal diseases. The aim of this review article is to update the reader on the multifaceted role of adipokines in the main rheumatic diseases such as osteoarthritis and rheumatoid arthritis and to unravel the complex interplay among adipokines, cartilage metabolism, bone remodelling and muscles, which will pave the way for innovative therapeutic intervention in the future. For completeness, the role of adipokines in intervertebral disc degeneration will be also addressed.

Adipokines in Rheumatoid Arthritis: Emerging Biomarkers and Therapeutic Targets

Rheumatoid arthritis (RA) is a chronic inflammatory disease manifested by joint involvement, extra-articular manifestations, and general symptoms. Adipose tissue, previously perceived as an inert energy storage organ, has been recognised as a significant contributor to RA pathophysiology. Adipokines modulate immune responses, inflammation, and metabolic pathways in RA. Although most adipokines have a pro-inflammatory and aggravating effect on RA, some could counteract this pathological process. The coexistence of RA and sarcopenic obesity (SO) has gained attention due to its impact on disease severity and outcomes. Sarcopenic obesity further contributes to the inflammatory milieu and metabolic disturbances. Recent research has highlighted the intricate crosstalk between adipose tissue and skeletal muscle, suggesting potential interactions between these tissues in RA. This review summarizes the roles of adipokines in RA, particularly in inflammation, immune modulation, and joint destruction. In addition, it explores the emerging role of adipomyokines, specifically irisin and myostatin, in the pathogenesis of RA and their potential as therapeutic targets. We discuss the therapeutic implications of targeting adipokines and adipomyokines in RA management and highlight the challenges and future directions for research in this field.

Circulating leptin and its correlation with rheumatoid arthritis activity: a meta-analysis

Objective

The aim of the study was to investigate the association between the levels of leptin in the circulating of individuals with rheumatoid arthritis (RA) and the severity of the disease.

Methods

We looked through the databases of Embase, Medline, and the Cochrane Library. We conducted a meta-analysis on the correlations between circulating leptin and the Disease Activity Score 28-erythrocyte sedimentation rate (DAS28-ESR) and C-reactive protein (CRP) levels in RA patients, as well as a meta-analysis of circulating or circulating leptin levels in RA patients.

Results

This meta-analysis study analyzed 42 different comparisons from 37 different publications, including a total of 2,350 patients with RA and 1,815 controls. The RA group had substantially higher leptin levels than the control group (standardized mean difference [SMD]=0.507, 95% confidence interval [CI]=0.309~0.704, p<0.001). The finding that RA patients had higher leptin levels was unaffected by sample size. The correlation between circulating leptin levels and DAS28 is statistically significant (correlation coefficient=0.247, 95% CI=0.087~0.396, p=0.003). Leptin levels are also correlated with CRP levels (correlation coefficient=0.203, 95% CI=0.048~0.349, p=0.010).

Conclusion

This comprehensive meta-analysis demonstrates that the circulating leptin levels of RA patients are elevated, and provides compelling evidence of the significant relationship between leptin levels and the activity of RA. The findings of this research suggest that leptin plays a significant role in the pathophysiology of this disease.

Leptin in Osteoarthritis and Rheumatoid Arthritis: Player or Bystander?

White adipose tissue (WAT) is a specialized tissue whose main function is lipid synthesis and triglyceride storage. It is now considered as an active organ secreting a plethora of hormones and cytokines namely adipokines. Discovered in 1994, leptin has emerged as a key molecule with pleiotropic functions. It is primarily recognized for its role in regulating energy homeostasis and food intake. Currently, further evidence suggests its potent role in reproduction, glucose metabolism, hematopoiesis, and interaction with the immune system. It is implicated in both innate and adaptive immunity, and it is reported to contribute, with other adipokines, in the cross-talking networks involved in the pathogenesis of chronic inflammation and immune-related diseases of the musculo-skeletal system such as osteoarthritis (OA) and rheumatoid arthritis (RA). In this review, we summarize the most recent findings concerning the involvement of leptin in immunity and inflammatory responses in OA and RA.

Leptin and Vascular Cell Adhesion Protein 1 as Physiological Biomarkers in Serum of Women Suffering from Rheumatoid Arthritis

BACKGROUND: Rheumatoid arthritis is defining as a common chronic and inflammatory disorder of systematic autoimmune disease. Leptin is a small peptide hormone involved in the inflammatory and immunomodulators processes of several diseases. AIM: The study aimed at evaluating the level of leptin and Vascular Cell Adhesion Protein 1 (VCAM-1) and proves that they act as vital markers in the serum of rheumatoid arthritis. MATERIALS AND METHODS: In this study, 80 serum samples from women were obtains (56 serum samples were distributing for women with rheumatoid arthritis and 24 serum samples for uninfected women who were considered a healthy group). RESULTS: There are no significant difference in the concentration of the leptin hormone in the serum of both patients and healthy women, and that age, period, and severity of the disease had no effect on the level of leptin hormone. However, the results confirmed that at the probability level p < 0.05 the VCAM-1 concentration increased significantly in patients’ serum when compared with the healthy group, and demonstrated that age groups only affected the VCAM-1 biomarker level. CONCLUSIONS: Our current study concludes that leptin levels in the serum were not impacts by the inflammatory state in patients with rheumatism, whereas VCAM-1 level in rheumatic patients may be associate with inflammatory reactions.

Plasma Leptin Does Not Reflect the Effect of High Body Mass Index on Disease Activity in Rheumatoid Arthritis

Background: The effect of obesity on disease severity in rheumatoid arthritis (RA) remains controversial. Adipocytes secrete pro-inflammatory cytokines and adipokines which may contribute to RA disease activity. The goal of the present study is to address the association between body mass index (BMI) with plasma levels of leptin, pro-inflammatory cytokines, and RA disease severity.Methods: Fifty RA patients (20 newly diagnosed and 30 under treatment) as well as 30 age- and sex-matched healthy subjects were included in this survey. The plasma levels of leptin and pro-inflammatory cytokines, including TNF-α and IL-6, were measured, and the results were compared among the patients in the three different categories of BMI, including <25, ≥25-30, and ≥30.Results: In our study, a significant positive correlation was observed between disease activity score-28 (DAS-28) and BMI in overweight (OW) RA patients (p = .036 r = 0.440). The plasma levels of leptin were significantly higher in patients group, compared to healthy subjects (p < .05); moreover, leptin levels were significantly higher in OW and obese patients compared to RA patients with normal BMI (p = .011, p = .001, respectively) and also BMI had positive correlation with leptin concentrations just in the newly diagnosed patients (p < .0001, r = 0.748). There was no correlation between leptin and DAS-28. The plasma IL-6 and TNF-α did not show significant differences between RA patients and healthy subjects, and also the plasma leptin did not have any correlation with plasma levels of IL-6 and TNF-α.Conclusion: BMI contribution to RA disease severity is independent of systemic levels of leptin and pro-inflammatory cytokines.

Gender-Specific Association of Leptin and Adiponectin Genes With Multiple Sclerosis

BACKGROUND

Adipocytokines such as leptin (LEP) and adiponectin (ADIPOQ) represent a link between metabolism, nutritional status and immune responses. The present study aimed to determine the possible association between single nucleotide polymorphisms of LEP and ADIPOQ genes with multiple sclerosis (MS).

MATERIALS AND METHODS

Single nucleotide polymorphisms in LEP (rs2167270 or 19G > A and rs7799039 or -2,548G > A) and ADIPOQ (rs1501299 or +276G > T and rs266729 or -11,377C > G) were genotyped in 305 patients and 255 healthy individuals using polymerase chain reaction-restriction fragment length polymorphism. Sera levels of leptin and adiponectin were measured using enzyme-linked immunosorbent assay.

RESULTS

The frequencies of low leptin producer rs2167270GG genotype and rs2167270G allele were significantly lower in patients with MS compared to those of controls (for GG genotype: 39.7% and 49.8%, respectively; P = 0.01; for G allele: 63.3% and 68.8%, respectively; P = 0.05). Both polymorphisms in ADIPOQ did not show any significant association with disease susceptibility, though after gender categorization the frequency of high adiponectin producer rs1501299TT genotype and rs1501299T allele were significantly higher in male controls compared to male patients (TT genotype: P = 0.006; T allele: P = 0.006). Additionally, rs1501299TT genotype in ADIPOQ was associated with susceptibility to primary progressive multiple sclerosis (PP-MS) (P = 0.02). Moreover, while the sera levels of leptin were only different between male patients and controls (P = 0.05), adiponectin levels were significantly higher in total and female healthy controls (P < 0.001, P = 0.002, respectively).

CONCLUSIONS

Our findings provide evidence to support the hypothesis that functional ADIPOQ and LEP gene polymorphisms are associated with susceptibility to MS and its clinical forms.

Circulating leptin level in rheumatoid arthritis and its correlation with disease activity: a meta-analysis

OBJECTIVE

This study aimed to evaluate the relationship between the circulating serum leptin level and rheumatoid arthritis (RA) and to establish a correlation between serum leptin levels and RA activity.

METHODS

We searched the PUBMED, EMBASE, and Cochrane databases. A meta-analysis was performed, comparing the serum/plasma leptin levels in patients with RA and healthy controls. Correlation coefficients between serum leptin level and either disease activity score 28 (DAS28) or C‑reactive protein (CRP) in RA patients were also examined.

RESULTS

Thirteen studies with a total of 648 RA patients and 426 controls were included in this meta-analysis. Circulating leptin level was significantly higher in the RA group than in the control group (SMD = 1.056, 95 % CI = 0.647-1.465, p = 4.2 × 10^-7). In addition, stratification by ethnicity showed a significantly elevated leptin level in the RA group in Caucasian, Turkish, and Arab populations (SMD = 0.813, 95 % CI = 0.137-1.490, p = 0.018, SMD = 0.981, 95 % CI = 0.307-1.655, p = 0.004, and SMD = 1.469, 95 % CI = 0.443-2.495, p = 0.005 respectively). A meta-analysis of correlation coefficients showed a small but significantly positive correlation between the circulating leptin level and either DAS28 (correlation coefficient = 0.275, 95 % CI = 0.076-0.452, p = 0.007) or CRP (correlation coefficient = 0.274, 95 % CI = 0.068-0.458, p = 0.010).

CONCLUSIONS

Our meta-analysis demonstrated that the circulating leptin level is significantly higher in patients with RA and that a small but significantly positive correlation exists between leptin levels and RA activity.

Zingiber officinale: A Potential Plant against Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease particularly affecting elderly people which leads to massive bone destruction with consequent inflammation, pain, and debility. Allopathic medicine can provide only symptomatic relief. However, Zingiber officinale is a plant belonging to the Zingiberaceae family, which has traditionally been used for treatment of RA in alternative medicines of many countries. Many of the phytochemical constituents of the rhizomes of this plant have therapeutic benefits including amelioration of RA. This review attempts to list those phytochemical constituents with their reported mechanisms of action. It is concluded that these phytochemicals can form the basis of discovery of new drugs, which not only can provide symptomatic relief but also may provide total relief from RA by stopping RA-induced bone destruction. As the development of RA is a complex process, further research should be continued towards elucidating the molecular details leading to RA and drugs that can stop or reverse these processes by phytoconstituents of ginger.