Lubricin in osteoarthritis

Lubricin a proteoglycan like molecule is present throughout the body but most noted for its presence in synovial fluid. Acting on the surface of articular cartilage it is thought to aid joint lubrication and support the joint fluid environment. Here is reported the review of 62 studies on the changes in lubricin concentration in degenerative joint disease and the effects of intra-articular injection of lubricin. Not surprisingly support for it’s use was found but I would caution the clinical significance is uncertain.

I believe that PAAG continues to show the most promise in the treatment of moderate to severe osteoarthritis Polyacrylamide hydrogel PAAG or PAHG
DrO

Osteoarthritis Cartilage. 2020 Jun 3.
Lubricin in experimental and naturally occurring osteoarthritis: a systematic review.
Watkins AR1, Reesink HL2.

Author information:
1. Department of Clinical Sciences, University of Pennsylvania School of Veterinary Medicine, New Bolton Center, Kennett Square PA.
2. Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY. Electronic address: hlr42@cornell.edu.
Abstract
OBJECTIVE:

Lubricin is increasingly being evaluated as an outcome measure in studies investigating post-traumatic and naturally occurring osteoarthritis. However, there are discrepancies in results, making it unclear as to whether lubricin is increased, decreased or unchanged in osteoarthritis. The purpose of this study was to review all papers that measured lubricin in joint injury or osteoarthritis in order to draw conclusions about lubricin regulation in joint disease.
DESIGN:

A systematic search of the Pubmed, Web of Knowledge, and EBSCOhost databases for papers was performed. Inclusion criteria were in vivo studies that measured lubricin in humans or animals with joint injury, that investigated lubricin supplementation in osteoarthritic joints, or that described the phenotype of a lubricin knock-out model. A methodological assessment was performed.
RESULTS:

Sixty-two studies were included, of which thirty-eight measured endogenous lubricin in joint injury or osteoarthritis. Nineteen papers found an increase or no change in lubricin and nineteen reported a decrease. Papers that reported a decrease in lubricin were cited four times more often than those that reported an increase. Fifteen papers described lubricin supplementation, and all reported a beneficial effect. Eleven papers described lubricin knock-out models.
CONCLUSIONS:

The human literature reveals similar distributions of papers reporting increased lubricin as compared to decreased lubricin in osteoarthritis. The animal literature is dominated by reports of decreased lubricin in the rat anterior cruciate ligament transection model, whereas studies in large animal models report increased lubricin. Intra-articular lubricin supplementation may be beneficial regardless of whether lubricin increases or decreases in OA.