The objective of this study was to evaluate the safety and the effect of platelet-rich plasma (PRP) intra-articular injections obtained from blood donors (homologous PRP) on elderly patients with early or moderate knee osteoarthritis (OA) who are not candidates for autologous PRP treatment. A total of 60 symptomatic patients, aged 65–86 years, affected by hematologic disorders and early or moderate knee OA, were treated with 5 ml of homologous PRP intraarticular injections every 14 days for a total of three injections. Clinical evaluations before the treatment, and after 2 and 6 months were performed by International Knee Documentation Committee (IKDC), Knee injury and Osteoarthritis Outcome Score (KOOS) and Equal Visual Analogue Scale (EQ VAS) scores. Adverse events and patient satisfaction were recorded. No severe complications were noted during the treatment and the follow-up period. A statistically significant improvement from basal evaluation to the 2-month follow-up visit was observed, whereas a statistically significant worsening from the 2-month to the 6-month follow-up visit was showed. The overall worst results were observed in patients aged 80 years or over and in those affected by minor bone attrition. It was found that 90% of patients were satisfied at the 6-month evaluation. Homologous PRP has an excellent safety profile but offers only a short-term clinical improvement in selected elderly patients with knee OA who are not candidates for autologous PRP treatment. Increasing age and developing degeneration result in a decreased potential for homologous PRP injection therapy. Further studies are needed to confirm these findings.
Nerve growth factor (NGF) is involved in several joint diseases. It participates in pain initiation, inadequate nociception and neurogenic inflammation; its concentrations are increased in synovial fluid and tissue from human and experimental arthritis. However, data about its role in normal and pathological articular cartilage are scant and conflicting. This study assesses the effects of different NGF concentrations on cultured healthy human chondrocytes by evaluating cell proliferation, cell phenotype, and gene expression. The 3-[4,5-dimethylthiazol-2-y1]-2,5-diphenyl-2H-tetrazolium bromide (MTT) test excluded an influence on cell viability; alcian blue and S100 staining demonstrated that NGF induced de-differentiation of the chondrocyte phenotype; real-time PCR disclosed that it reduced the expression of collagen type II (COL2A1) and transforming growth factor-β (TGF-β), key factors involved in articular cartilage integrity, and stimulated upregulation of metalloproteinase (MMP)-3 and MMP-13. These findings suggest that NGF may adversely affect differentiated chondrocytes from articular cartilage by inhibiting the expression of the collagens found in normal articular cartilage (COL2A1), while exerting a degradative effect though TGF-β downregulation and MMP-13 and MMP-3 upregulation. Further investigation is required to determine whether the gene expression pattern found in our study is associated with changes in protein expression.
