Interactions of growth factors and degenerating enzymes in intraabdominal adhesions in infants

The morphopathogenesis of intraabdominal adhesions is a complex process, characterized by the accumulation of extracellular matrix. The aim of this study was to explore the appearance of transforming growth factor β (TGFβ), vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2), as well as describe their interactions in intra-abdominal adhesions. The study material was obtained from infants who underwent abdominal surgery due to complete or partial bowel obstruction. 50 specimens were rated appropriate for immunohistochemistry and factors were assessed according to the semiquantitative counting method. To evaluate the cross-compliance of two variables Spearman's rank correlation coefficient (r) was calculated. In our study overall moderate (++) number of structures contained TGFβ. A few to moderate (+/++) number of MMP-2 positive endotheliocytes, fibroblasts and inflammatory cells were detected. The TIMP-2 findings were variable – from few (+) to moderate to numerous (++/+++) positive structures. We observed a similarly tight positive correlation between MMP-2 and VEGF (r = 0.511, p < 0.001), as well as between TIMP-2 and VEGF (r = 0.593, p < 0.001). Statistically significant moderately tight, positive correlations were observed between MMP-2 and TIMP-2 (r = 0.489, p < 0.001). A statistically significant moderately tight, negative correlation was observed between VEGF and TGFβ findings (r = -0.401, p = 0.005). We observed a negative correlation between TGFβ and MMP-2 findings (r = -0.333; p = 0.021). The balance of MMP-2/TIMP-2 is a significant factor for the regulation of VEGF and has an angiogenesis promoting impact. The suppression of VEGF under the impact of TGFβ might be a compensatory mechanism in the development of intraabdominal adhesions. TGFβ inhibits the activity of MMP-2, therefore it stimulates the accumulation of extracellular matrix components and also delays its degradation.