Clinical outcomes, biological analysis may provide understanding of responses to PRP
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Key takeaways:
- Platelet-rich plasma modulated cellular responses to inflammatory factors.
- Higher concentrations of inflammatory mediators did not have an association with poorer clinical response.
NEW ORLEANS — Results showed integrating clinical outcomes with laboratory analysis of biological samples may lead to a better understanding of the variable responses to platelet-rich plasma therapy for musculoskeletal conditions.
“We hope that implementation of this integrative workflow, bridging state-of-the-art comprehensive biological analyses with rigorous analyses of clinical outcomes, in future larger randomized controlled trials for knee osteoarthritis or other musculoskeletal conditions can lead to the discovery of differences in PRP composition and bioactivity that can predict clinical responses to PRP or at least help clinicians and researchers better understand why patients respond variably to PRP,” Xiaoning (Jenny) Yuan, MD, PhD, assistant professor and vice chair for research in the department of physical medicine and rehabilitation at the Uniformed Services University, told Healio about results presented at the Biologic Association Annual Summit.
PRP for knee OA
Yuan and colleagues collected baseline demographics, clinical and imaging information, and approximately 1 mL of PRP for laboratory analysis among 51 patients with knee OA who were already recommended for intra-articular PRP injection by their physician. Researchers collected patient-reported outcome measures (PROMs) at baseline and at different time points after PRP injection to stratify responders and non-responders.
“Specifically, participants’ responses at 6 months for the Knee injury and Osteoarthritis Outcome Score for Joint Replacement and numeric pain rating scale were used to identify responders, those who met the minimal clinically important difference (MCID) for both PROMs, and non-responders, those who did not meet the MCIDs for both PROMs,” Yuan told Healio.
Researchers then established an in vitro cellular model using macrophages and fibroblasts to mimic joint inflammation to study the responses to PRP.
“Our aim was to test if the PRP composition and bioactivity in vitro were associated with clinical outcomes for patients treated with PRP for knee OA,” Yuan said.
Results showed PRP modulated cellular responses to inflammatory factors. Yuan and colleagues identified chemokine ligand 5 “as a robust target for evaluating the in vitro responses of fibroblasts and macrophages to PRP.”
Larger cohorts needed
Yuan said higher concentrations of inflammatory mediators did not have an association with poorer clinical response. Researchers also did not find differences in the composition of key factors analyzed, including interleukin-1 receptor antagonist, vascular endothelial growth factor, epidermal growth factor or transforming growth factor-beta, but did detect small differences in interleukin-7 protein. No major differences were observed in the bioactivity of PRP between responders and non-responders, according to Yuan. She added the differences found were cell- and gene-specific.
“Because our sample size was small, we cannot confirm that these differences are present in larger patient cohorts or that they have a clinical connection,” Yuan said. “We believe that follow-up studies with larger patient cohorts and analysis of a wider array of proteins and genes are required to further define the components of PRP that are associated with clinical outcomes, and our workflow may help inform these future studies.”
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Yuan XJ, et al. Assessment of the composition and biologic activity of PRP and its relationship to clinical outcomes in patients with knee OA. Presented at: Biologic Association Annual Summit; May 6-7, 2023; New Orleans.
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