Osteoarthritis Pathology Potentially Associated with Estrogen

Researchers at Augusta University found a significant difference in miRNA expression between men and women with osteoarthritis (OA), suggesting that the pathology of the disease is associated with the availability of estrogen.

In their study, the researchers isolated exosomes from discarded human synovial fluid collected from patients with and without OA.
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Synovial fluid from female patients with OA showed 91 downregulated and 53 upregulated miRNA, which was significantly higher than the 69 downregulated and 45 upregulated miRNA found in the synovial fluid of male patients with OA. Overall, females had more than 70 biological processes altered compared to males who had closer to 50.

In addition, the researchers assessed the influence of estrogen on miRNA found in exosome by using an aromatase inhibitor that reduced the availability of estrogen. The lack of estrogen was found to reduce the number of miRNA associated with joint health.

Likewise, an experiment using healthy cartilage cells from female synovial fluid samples that were treated with exosomes from both male and female patients with OA showed an increase in inflammation and reduction in the genes responsible for cartilage.

MiR-504-3p was upregulated in both female and male patients. Although researchers were unable to determine its effects, they hypothesized that the gene degenerated cartilage and intend to determine its function within the pathology of OA in future studies.

“Synovial fluid exosomal miRNA content is altered in patients with OA and these changes are gender specific,” the researchers concluded.

—Melissa Weiss

Reference:

1) Kolhe R, Hunter M, Liu S, et al. Gender-specific differential expression of exosomal miRNA in synovial fluid of patients with osteoarthritis [May 17, 2017]. Scientific Reports. doi:10.1038/s41598-017-01905-y.

2) Baker, T. Protective fluid in the knee holds clues for why osteoarthritis is more common in females [press release]. Augusta, GA: Jagwire News; June 26, 2017. https://jagwire.augusta.edu/archives/45527.