Absence of a positive correlation between CRP and leptin in rheumatoid arthritis.

Seyed Reza Najafizadeh,Atieh Pajouhi,Ahmad Tahamoli Roudsari,Mehrdad Larry,Behnam Heidari,Alireza Esteghamati,Manouchehr Nakhjavani,Arash Aghajani Nargesi,Ghasem Farahmand

doi:10.1016/j.heliyon.2016.e00205

Seyed Reza Najafizadeh, Atieh Pajouhi + Show 7 more

Open Access

https://doi.org/10.1016/j.heliyon.2016.e00205

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Abstract

AimsRheumatoid Arthritis (RA) is a model of chronic inflammatory disease. In this study we evaluated the correlation of leptin and CRP in patients with RA and normal controls.Main methodsA total of 75 patients with RA and 40 healthy adults were recruited in this case-control study. RA patients were categorized into high (DAS–28 > 3.2) and low activity (DAS ≤ 3.2) group according to their DAS-28 score.Key findingsLeptin level was significantly correlated with CRP in healthy controls (r = 0.365; p < 0.05), but this correlation was lost in RA patients (r = 0.095, p = 0.41). Patients with RA had higher serum leptin levels compared to healthy controls (P < 0.01). No difference in serum leptin level was observed between patients with high and low activity disease. Also leptin was correlated with BMI in healthy controls (r = 0.326, p = 0.037). This correlation was not present in RA patients (r = 0.039, p = 0.756).SignificanceWe observed that the physiologic correlation between leptin and CRP and BMI and CRP was not present RA patients. This is a new study reporting the lost correlation between leptin and CRP in RA patients.

Highlights

The role of cytokines in development and progression of rheumatoid arthritis has been studied earlier [1, 2, 3, 4]
It is previously shown that leptin and CRP are correlated in healthy individuals [15, 18], and we reported the lost correlation between CRP and leptin in type 2 diabetes mellitus [15]
We previously reported the lost correlation between CRP and leptin in patients with type 2 diabetes mellitus [15], in which inflammation is considered to be a cornerstone of the disease

Summary

Introduction

The role of cytokines in development and progression of rheumatoid arthritis has been studied earlier [1, 2, 3, 4]. Leptin is a non-glycosylated peptide hormone belonging to type 1 cytokine superfamily, and its structure is similar to interleukin (IL)-2, IL-6 and granulocyte colony-stimulating factor (G-CSF) [5, 6]. It is mainly produced by white adipose tissue and is known as the regulator of appetite and energy intake, alongside hematopoiesis, angiogenesis, endocrine and more recently as a mediator of immune mediated and inflammatory processes [7]. It is shown that leptin plays role in the activation and proliferation of various immune cells and cytokine production that potentially affects both innate and adaptive immune systems and inflammation in human and animal models [7, 9, 10]. Regarding the inflammatory properties of leptin, determining its correlation with RA and its activity has been studied [3, 4, 11, 12, 13]

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