Neuroimmune expression in hip osteoarthritis: a systematic review

Hip osteoarthritis (OA) is a severe health condition and a major cause of pain and disability among adults. Neuroimmune axis have been established an important player in the pathogenesis of hip OA. Despite the availability of many studies, none of them demonstrate the general profile of neuroimmune expression OA. Therefore, a systemic review conducted by Manuel Ribeiro da Silva et al found the upregulation of neuroimmune markers, with the deregulated balance between pro and anti-inflammatory cytokines in patients with hip OA.

The major part of the hip osteoarthritis (OA) physiopathology is neuroimmune axis, however, its particular pathways are still unclear. This systematic review intends to evaluate the immune and nervous system profile of the individuals with hip osteoarthritis (OA) as compared to the healthy controls.

PRISMA guidelines were followed and conducted the systematic review. A two-step election process was performed, and 17 references were involved. Original articles on adult individuals with hip OA along with the evaluation of neuroimmune expression was taken for the inclusion criteria. Some of the articles were excluded who were without a control group or with other interventions before analysis. 

A total of 39 relevant neuroimmune markers were recognised with evaluations in cartilage, bone, whole blood, immune cells, serum, synovial fluid, and synovial membrane. During the comparison between controls and hip OA, IFN-γ, TNF-α, IL-1, IL-6, IL-8, IL-1α, and GM-CSF exhibited variable expression among tissues.  TGF-ß and VEGFs isoforms displayed comparable tendencies amid tissues and studies. On nervous expression, Tuj-1, SP, and CGRP were raised in the synovial membrane. All-inclusive, individuals with hip OA showed a greater number of overexpressed markers.

For the first time, a systematic review on neuroimmune expression within persons with hip OA discovered an upregulation of neuroimmune markers, with a deregulated balance within pro and anti-inflammatory cytokines. Although, no clear systematic pattern was observed, and less data is available on nervous expression. This enlightens the importance of prospective investigation with clear methodologies to guide the management of such cases.