Biological injection therapy with leukocyte-poor platelet-rich plasma induces cellular alterations, enhancement of lubricin, and inflammatory downregulation in vivo in human knees: A controlled, prospective human clinical trial based on mass spectrometry imaging analysis

Women show a positive response to platelet-rich plasma despite presenting more painful knee osteoarthritis than men

PURPOSE

The purpose of this study was to evaluate the impact of gender on the efficacy of platelet-rich plasma (PRP) in patients with knee osteoarthritis (KOA), comparing their short-term response between men and women.

METHODS

Four hundred-eighteen patients (529 knees) were included. Patients were treated with three injections of PRP on a weekly basis. Blood and PRP samples were randomly tested. Patients were asked to complete the knee injury and osteoarthritis outcome score (KOOS) and 12-item short form survey (SF-12), at baseline and 6 months. Success rates were calculated according to a reduction in the pain score of at least 9.3 points [minimal clinically important improvement (MCII)]. Comparative tests and multivariate regression were performed.

RESULTS

The PRP had a platelet concentration factor of 2.0X compared to blood levels, with no leucocytes or erythrocytes. KOOS scores showed an increase from baseline to 6 months (p < 0.0001). There was an increase in the physical component summary (PCS) (p < 0.0001) and mental component summary (MCS) (p < 0.01) of the SF-12. The number of knees of women with MCII was 156 out of 262 (59.6%), whereas the number of knees of men was 136 out of 267 (50.9%) (p = 0.0468). Women had worse baseline scores on pain (p = 0.009), PCS (p < 0.0001) and MCS (p < 0.0001).

CONCLUSION

Although the symptomatology generated by KOA was worse in women when compared to men, treatment with repeated injections of PRP was effective, ultimately achieving a higher improvement in women providing comparable final follow-up outcomes between men and women.

LEVEL OF EVIDENCE

Level IV.

Molecular analysis of the extracellular microenvironment: from form to function

The extracellular matrix (ECM) proteome represents an important component of the tissue microenvironment that controls chemical flux and induces cell signaling through encoded structure. The analysis of the ECM represents an analytical challenge through high levels of post-translational modifications, protease-resistant structures, and crosslinked, insoluble proteins. This review provides a comprehensive overview of the analytical challenges involved in addressing the complexities of spatially profiling the extracellular matrix proteome. A synopsis of the process of synthesizing the ECM structure, detailing inherent chemical complexity, is included to present the scope of the analytical challenge. Current chromatographic and spatial techniques addressing these challenges are detailed. Capabilities for multimodal multiplexing with cellular populations are discussed with a perspective on developing a holistic view of disease processes that includes both the cellular and extracellular microenvironment.