Tissue-Specific Expression of Glutathione-S-Transferase Isoforms in Myelomeningocele: An Immunohistochemical Study

Myelomeningocele (MMC), the common form of open spina bifida, is a neural tube defect characterized by lifelong neurological and systemic complications. Recent evidence suggests that reduced free radical scavenging enzyme activity such as glutathione-S-transferase (GST) activity may have role in the development of this condition. However, data on isoform-specific GST-expression in MMC tissues are scarce.

Twenty-five patients who underwent surgical repair for MMC between September 2019 and August 2021 were included. During surgery, biopsy specimens containing skin, skin appendages, meninges, endothelium, and inflammatory areas were collected. Immunohistochemistry was performed using antibodies against GST-sigma, GST-kappa, GST-theta, GST-omega, and GST-pi. Expression frequencies were analyzed.

Significant differences in GST isoform expression were observed within and across tissue types. In skin and appendages, GST-omega, GST-kappa, and GST-pi were expressed more frequently. In meningeal tissue, GST-theta expression was absent, whereas other isoforms were frequently detected. Inflammatory tissue showed higher expression of GST-omega compared with GST-sigma (p = 0.004). Endothelial cells demonstrated low and nonsignificant expression differences among isoforms.

GST isoform expression in MMC is tissue-specific, with GST-omega, GST-kappa, and GST-pi predominating in skin-related structures and GST-theta absent in meningeal tissue. These results suggest that antioxidant defense in MMC is not uniform across tissues and highlight the importance of isoform-level analyses in understanding the pathophysiology of neural tube defects.