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Higher Leptin Levels Detected in Patients with Rheumatoid Arthritis

Leptin levels are higher in patients with rheumatoid arthritis (RA), and the consumption of leptin within the joints may have a protective role in joint erosion, say researchers.

Leptin is a signalling molecule that is produced mostly by adipose tissue and is known to regulate food intake, basal metabolism, and the beta-oxidation of fatty acids. However, leptin has also been shown to play a role in bone remodelling and has shown both pro-inflammatory and anti-inflammatory effects.

The effects of leptin in the pathology and progression of arthritis is unknown, and preliminary animal studies have yielded contradicting results. Further analysis is needed to understand the role of leptin in arthritis and joint destruction.

Dr. Maria Bokarewa and colleagues at the Sahlgrenska University Hospital, Goteborg, Sweden, evaluated the levels of leptin present in the joints of RA patients.

The study included 76 patients (28 men and 48 women) with RA who were under current treatment with non-steroidal anti-inflammatory drugs (NSAIDs), disease modifying antirheumatic drugs (DMARDs), or glucocorticoids, and 34 healthy controls. Plasma and synovial samples were collected from patients and leptin levels were measured in these samples by an enzyme-linked immunosorbent assay (ELISA). Radiographic analysis and disease activity were also assessed.

Overall, results indicated that higher levels of leptin were found in patients with RA than in control samples. Furthermore, plasma and joint fluid leptin levels showed a strong correlation; though the level of plasma leptin was significantly higher than that detected in the synovial fluid.

In addition, leptin levels in the synovial fluid of patients with RA were higher in those with erosive disease compared to those without erosive disease. Moreover, leptin levels in both the plasma and the synovial fluid increased with longer disease duration. Further analysis also revealed that the difference between matched plasma and joint leptin levels was significant in patients with non-erosive disease (5.1 ng/ml vs. 3.7 mg/ml, p=0.006), but not in those with erosive disease.

Another interesting observation was that patients treated with DMARDs had significantly lower levels of plasma leptin than non-DMARDs treated patients; however, those given methotrexate had significantly higher leptin levels in both plasma and joint fluid samples.

Dr. Bokarewa concludes that this study "demonstrated a significant increase of circulating leptin levels in patients with RA compared with healthy controls." She further notes that "local consumption of leptin in the joint cavity was associated with non-erosive joint disease, suggesting that leptin has a protective role against the destructive course of RA."


Ann Rheum Dis 2003 Oct;62:1):952-6. "Leptin consumption in the inflamed joints of patients with rheumatoid arthritis"

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