Can pain intensity in osteoarthritis joint be indicator of the impairment of endothelial function?

We propose that pathological remodeling in joint tissues of osteoarthritis (OA) patients persistently stimulates local secretion of pro-inflammatory mediators, which overflow into the blood, activating leukocytes that impair endothelial function and accelerate the atherosclerotic process. During periods of pain, endothelial dysfunction progresses more aggressively due to elevated secretion of these pro-inflammatory mediators, which are involved in both atherosclerosis and the sensation of pain. Concentrations of pro-inflammatory cytokines and their antagonists, activating and decoy receptors of the broad interleukin (IL)-1 and IL-17 families, IL-15, and monocyte chemotactic protein-1 should be measured in peripheral blood samples of OA patients and compared with (I) OA clinical severity; (II) subclinical parameters of atherosclerosis; (III) ischemic heart disease risk factors; (IV) soluble factors indicating endothelial dysfunction; (V) degree of bone destruction; and (VI) results of a six-minute walk test. Arthroscopy and joint replacement surgery provide an opportunity to estimate mRNA and protein expression of inflammatory mediators in specimens of synovial fluid, synovial membrane, cartilage, and/or subarticular bone. A range of methods, including questionnaires, X-ray, computed tomography, ultrasound, enzyme-linked immunosorbent assay, immunohistology, immunofluorescence, and reverse transcription and in situ polymerase chain reaction are available. Understanding the inflammatory and immune mechanisms underlying OA may allow the early identification of patients at high risk of cardiovascular disease, independently of classical coronary risk factors. Pain may constitute an extrinsic indicator of currently worsening endothelial function.