Insulin-like growth factor (IGF)-I plays an important role for maintaining cardiac functions. We clarified the unknown role of IGF-axis in rheumatic heart disease (RHD).
Interleukin (IL)-10, growth hormone (GH), IGF, IGF binding protein (IGFBP)-3 and matrix metalloproteinase (MMP) were measured by ELISA and zymography in 30 age range-matched normal subjects (control), 36 patients with acute phase of rheumatoid arthritis (RA) with positive rheumatoid factor (RF) and C-reactive protein (CRP), and in 43 patients with RHD with negative RF and CRP.
Compared with normal subjects, increased IL-10 level and decreased GH were found in RA group whereas unchanged IL-10 and decreased GH were found in RHD group. Compared with age range-matched normal subjects, decreased IGFBP-3, MMP-9 levels, unchanged IGF-I were found in RA group whereas decreased IGF-I levels, unchanged IGFBP3 and increased MMP-9 at age>30 years were found in RHD group. IGF-II was not changed in RA and RHD groups.
These findings may imply that during inflammatory phase, the levels of anti-inflammation was high and total IGF-I and IGF bioavailability were maintained in patients with RA. Our findings in RHD may speculate that the long-term reduction of GH and IGF-I as well as the compensating effects of upregulated MMP-9 activity may be partially involved in the long-term pathogenesis from RHD to heart failure. Decreased GH, decreased IGF-I and increased MMP-9 activities may be possible diagnostic markers in RHD for developing heart failure.