(115) Interleukin-6 is Associated with Abdominal Muscle Growth in Knee Osteoarthritis Patients

Abstract

Interleukin-6 (IL-6) is a cytokine with various functions ranging from regulating inflammatory pathways to immune system responses. Pro-inflammatory cytokines are associated with excess inflammation which has been implicated as a mechanism in the transition from acute to chronic pain. However, through the classic signaling pathway, IL-6 can also act as an anti-inflammatory myokine, an indication of muscle growth and myogenesis. However, its association with body composition and how they are associated with pain following surgery are not well defined. The current secondary analysis evaluated the association between serum IL-6 and body composition in 24 knee osteoarthritis patients. Participants underwent one DEXA scan, laboratory pain testing procedures and a series of questionnaires approximately four weeks prior to total knee replacement. Laboratory pain testing and questionnaire data were repeated approximately eight weeks following surgery. The percentage of lean abdominal muscle was significantly associated with baseline IL6 levels as well as IL6 reactivity following pain testing (r's = 0.4-0.6, p's ∼ 0.008). Additional analyses will focus on associations between pain measures, circulating IL6 and reactivity, and body composition to evaluate the moderating role of body composition, specifically with regard to lean muscle in the trunk. In addition to monitoring for negative outcomes after surgery such as infection, clinicians also need a strategy to determine the procedure's potential for success. In surgical procedures that are designed to improve musculoskeletal function, IL-6 may be an effective marker to determine the metabolic activity and function in skeletal muscle in the post-operative period. Our study shows a positive association between lean muscle mass and serum IL-6 levels. These results encourage further analyses regarding the association between IL-6 and body composition in determining pain outcomes following surgery.