Rheumatoid Arthritis: Gómez R

Lago R, Gómez R, Lago F, Gómez-Reino J, Gualillo O. · Santiago University Clinical Hospital, Research Laboratory 4 (NEIRID LAB, Laboratory of Neuro Endocrine Interactions in Rheumatology and Inflammatory Diseases), Calle Choupana s/n, 15706 Santiago de Compostela, Spain. · Cell Immunol. · Pubmed #18289518 No free full text.

Abstract: Leptin, a 16 kDa non-glycosylated polypeptide produced primarily by adipocytes and released into the systemic circulation, exerts a multitude of regulatory functions including energy utilization and storage, regulation of various endocrine axes, bone metabolism, and thermoregulation. In addition to leptin's best known role as regulator of energy homeostasis, several studies indicate that leptin plays a pivotal role in immune and inflammatory response. Because of its dual nature as a hormone and cytokine, leptin can be nowadays considered the link between neuroendocrine and immune system. The increase in leptin production that occurs during infections and inflammatory processes strongly suggests that this adipokine is a part of the cytokines network which governs inflammatory/immune response and host defence mechanisms. Indeed, leptin plays a relevant role in inflammatory processes involving either innate or adaptive immune responses. Several studies have implicated leptin in the pathogenesis of autoimmune inflammatory conditions such as encephalomyelitis, type I diabetes, bowel inflammation and also articular degenerative diseases such as rheumatoid arthritis and osteoarthritis. Although the mechanisms by which leptin exerts its action as modulator of inflammatory/immune response are likely to be more complex than predicted and far to be completely depicted, there is a general consensus about its pivotal role as pro-inflammatory and immune-modulating agent. Here, we review the most recent advances on leptin biology with a particular attention to its adipokine facet, even though its role as metabolic hormone will be also addressed.

Otero M, Lago R, Gómez R, Lago F, Gómez-Reino JJ, Gualillo O. · Beth Israel Deaconess Medical Center, New England Baptist Bone & Joint Institute, Harvard Institutes of Medicine, Boston, Massachusetts, USA. · Drug News Perspect. · Pubmed #16550253 No free full text.

Abstract: Initially described as a satiety factor with neuroendocrine properties, leptin has been shown to regulate immune and inflammatory processes. Mainly produced by white adipose tissue, this hormone was first known to regulate energy homeostasis by inhibiting food intake and by upregulating energy consumption. Leptin is a dual molecule: apart from its actions as a hormone involved in energy homeostasis, increasing evidence suggests that leptin is a novel proinflammatory adipocyte-derived factor that operates in the cytokine network by linking immune and inflammatory processes to the neuroendocrine system. In fact, recent findings have shown that leptin regulates and participates both in immune homeostasis and inflammatory processes not only by acting as a modulator of T-cell activity, but also by playing a key role in a host of autoimmune inflammatory conditions such as autoimmune encephalomyelitis, type 1 diabetes, bowel inflammation and articular degenerative diseases such as osteoarthritis and rheumatoid arthritis. This review will more closely address leptin's cytokine properties rather than its role as a metabolic hormone by focusing on its biological actions in inflammatory processes, specifically those related to degenerative inflammatory diseases of the joints.