Synovial mast cells from knee and hip osteoarthritis: histological study and clinical correlations.

PURPOSE: The aim of this study was to investigate the presence of synovial mast cells (MCs) in hip and knee tissue from osteoarthritis (OA) patients and to correlate them with clinical and radiological data. METHODS: Synovial tissue was obtained during arthroplasty from 60 patients, 30 with knee OA and 30 with hip OA. Control synovial tissue was obtained from 30 patients without OA, 15 undergoing above-knee amputation and 15 receiving a hip replacement for fracture. Before surgery, the radiographic findings were graded according to the Kellgren-Lawrence system and clinical data including pain (VAS) and functional information (KOOS and HOOS) was collected. The tissue was stained with hematoxylin-eosin and toluidine blue for histochemistry and incubated with CD117 and CD31 antibodies for immunohistochemistry. MC and vessel number and synovitis score were determined in all samples. RESULTS: Mean MC number, synovitis score and vessel number were significantly higher in the OA samples (p < 0.05) than in control tissue. MC number correlated with the synovitis score and disease severity in both patient groups. CONCLUSIONS: The prevalence of MCs in synovium from OA patients and their association with synovial inflammation and pain suggest a role for them in OA pathophysiology.

Characterization of human costal cartilage: is it an adapt tissue as graft for articular cartilage repair?

Several techniques and different biological or artificial tissues have been proposed as graft to restore articular defects. However, among the numerous and heterogeneous procedures proposed over time, the current literature findings are not conclusive. The aim of the current study is to evaluate if human costal cartilage can be suitable as graft for restoring articular cartilage defects. Knee articular cartilage and costal cartilage samples were obtained respectively from patients that underwent anterior cruciate ligament reconstruction (samples from notch plasty) or knee joint replacement and ear reconstruction or rhinoplasty through rib graft. The samples were stained with hematoxylin eosin, safranine-O, Gomori paraldehyde-fuchsin and Von Kossa for light microscopy. Immunohistochemistry was performed using anti-collagen I, II, IV and anti-SOX9 antibodies. Furthermore, samples were analyzed by transmission electron microcopy (TEM). In both cartilage, the cells are arranged in quite similar layers and the matrix show the same hyaline appearance: presence of type II collagen and solphated glycosaminoglycans, and absence of type I collagen and SOX-9. The bigger difference between the two hyaline tissues is the presence of perichondrium that surrounds all the specimens of costal cartilage. It consists of two separate layers where the inner one seems to get thinner with aging. The results show that rib cartilage seems to be an adapt tissue as graft for articular cartilage repair from a histological point of view. However, to date its therapeutic potential remains to be clearly defined by animal and clinical studies.

The effect of anti-IgE therapy in knee osteoarthritis: a pilot observational study.

Osteoarthritis is a whole-joint disease and its pathogenesis remains poorly understood. Recent evidence proposed the importance of the innate immune system as trigger of synovium inflammation following the degeneration of cartilage. Moreover, synovial mast cells (MCs) might be correlated with pain and disability reported by patients. Anti IgE therapy represents a new class of MCs stabilizing agent, licensed for people with asthma and chronic urticaria. Therefore, we studied if the stabilizing effect of anti IgE would improve the pain and disability in patients affected by knee osteoarthritis and atopic disease. This pilot study provides the first evidence that anti IgE treatment induces a short-term clinical improvement supporting the role of MCs in osteoarthritis.

Homologous platelet-rich plasma for the treatment of knee involvement in primary Sjögren’s syndrome.

Primary Sjögren’s syndrome (pSS) is a chronic autoimmune disease characterized by dry eyes, dry mouth, and other clinical manifestations. The most common extraglandular manifestation of pSS is articular involvement and to date their management is unclear. The aims of the current pilot study were to assess the safety and the outcomes of homologous platelet-rich plasma (HPRP) injections in pSS cohort affected by knee arthralgia/arthritis at short-term follow up. This pilot study provides the first evidence that HPRP injections are a safe treatment and induce a short-term clinical improvement. Although the lack of a control group, randomization and long-term follow up prevents the assessment of the real effectiveness of this treatment, further studies are needed to confirm these findings and to determine the mechanism of action, biological changes and disease-modifying properties of PRP.