Review Question - QID 330

The basement membrane is not disrupted in rheumatoid arthritis-affected synovial tissue, as synovium lacks a true basement membrane.

Normal synovium consists of two layers, the intimal and the sublining, and two types of cells, type A and B. In RA, the following changes to the synovium are seen: 1) hyperplasia, with the intimal lining increasing from two cell layers to 10-20 layers 2) decreased apoptosis of the lining 3) increased angiogenesis and 4) abundant lymphocytes around vessels, forming lymphoid follicles.

The synovial pannus is invasive granulation tissue that contains fibroblast-like synoviocytes, but few inflammatory cells. The synovial cells in the pannus have anchorage-independent growth and invasive capabilities, allowing them to directly attack and destroy articular cartilage.

Koch et al. note that the possible contributions of angiogenesis to the proliferation of the inflammatory synovial pannus and the ingress of inflammatory leukocytes into the synovial tissue in RA have been extensively studied. Relevant angiogenesis inducers seen in RA include FGF-2, VEGF, TGFß, TNFa, IL-1, IL-8, VCAM-1, among others. Modulation of angiogenesis may be a viable therapeutic option for RA in the future.

Incorrect Answers:
Answer 1, 2, 3, 5: Synovium affected by rheumatoid arthritis has all of these characteristics.