IGF-II and MMP9 as surgical repair indicators of ventricular septal defects

Objective: The insulin-like growth factor-I (IGF-I), insulin-like growth factor binding protein-3 (IGFBP-3) and human growth hormone (h-GH) have been recognized as therapeutic targets for the heart disease therapy. The bioavailability and actions of insulin-like growth factors-II (IGF-II) and matrix metalloproteinase-9 (MMP9) are important for embryonic development and cardiomyocyte differentiation as well. However, the clinical manifestations following the change in the serum IGF-II and MMP9 in infants with isolated ventricular septal defect (VSD) undergoing surgical repair have not been clearly defined. Study design: Serum samples were collected from 72 infants: Twenty normal infants (group I) and 51 consecutive infants with echocardiography established isolated VSD (aged from 3. months to 1. year) were investigated. Among the 51 infants with VSD, 28 with shunt fraction, Qp/Qs< or = 1.5 were free of congestive heart failure symptoms (group II); 23 with shunt fraction, Qp/Qs> or = 2.0 were in congestive heart failure (group IIIa); and 23 of these 23 infants had undergone VSD repair 6. months before their second study (group IIIb). All insulin-like growth factors-II (IGF-II) and human growth hormone (h-GH), insulin like growth factor binding protein-3 (IGFBP-3) and its specific serum protease-MMP9 concentration were analyzed using ELISA and zymography, respectively. Results: Serum IGF-II and MMP9 exhibited significant decreasing trends among the three groups and significantly lower concentrations of IGF-II, IGF-II/IGFBP-3 ratio and MMP9, were found only in the severe group whereas h-GH/IGF-II ratio became significantly higher in this group. Moreover, there were no significant differences in these parameters between the infants after surgical correction and the normal ones. Conclusions: The improvement in IGF-II and MMP9 serum concentration was identified in infants with VSD after surgical repair. These findings also indicate a significant relationship between IGF-II, MMP9 and VSD which might be used as diagnosis and prognosis indicators for this defect. Slight reductions in IGF-II/IGFBP3 ratio and slight increase in the h-GH/IGF-II ratio indicate mild VSD. The reductions in the MMP9, IGF-II, and IGF-II/IGFBP3 ratio plus high increase in the h-GH/IGF-II ratio indicate severe VSD.