Matrix metalloproteinase-7 and matrix metalloproteinase-9 expression is upregulated in congenital lung malformations.

Background: Congenital lung malformations (CLMs) refer to structural abnormalities of the lungs that occur during fetal development. Matrix metalloproteinases (MMPs) constitute a group of zinc-dependent enzymes, with certain members of this family playing pivotal roles in the remodeling of the lungs both prenatally and postnatally. This study aimed to explore expression levels of MMP-2, MMP-7, and MMP-9 in CLMs which are recognized as pivotal contributors to their clinical pathology.

Methods: A total of 41 patients between the ages of 0-17 years that had undergone lung surgery for CLMs between March 2007- July 2023 were analyzed. The demographic features, clinical and pathological findings were recorded. The expression levels of MMP-2, MMP-7 and MMP-9 in patients' tissues were examined by reverse transcription polymerase chain reaction and compared in CLMs and adjacent normal lung tissues.

Results: Among patients with CLMs, 12 patients had congenital pulmonary airway malformations (CPAM, one patient had bilateral lesions), 18 patients had bronchopulmonary sequestration (BPS), 7 patients had congenital lobar overinflation (CLO), and 4 patients had bronchogenic cyst (BC). The higher expression of MMP-7 and MMP-9 in all CLM tissues compared to normal tissue was observed. But, there was a trend in MMP-2 expression in CPAM tissues and MMP-2 showed high expression in the BPS, CLO and BC groups, which was not statistically significant. Upon collective analysis of all groups, it was observed that mRNA expressions of MMP-7 and MMP-9 exhibited greater upregulation in CPAM and BC in comparison to BPS and CLO.

Conclusions: Our findings indicate a specific involvement of MMP-7 and MMP-9 in the pathogenesis of CLMs, particularly in CPAM and BC. To the best of our knowledge, this research represents the initial demonstration of MMP expression in CLMs.