Turkish Neurosurgery
Tissue Expressions of Regulatory Enzymes of the Krebs Cycle in Low- and High-grade Gliomas
burak tahmazoglu1, rahsan kemerdere1, mehmet edip akyol2, bagnu orhan3, merve ince3, huriye serin3, berrin bercik inal3, tibet kacira4, taner tanriverdi1
1istanbul university-cerrahpasa, cerrahpasa medical school, neurosurgery, istanbul,
2van yuzuncu yil university medical school, neurosurgery, van,
3istanbul education and research hospital, biochemistry, istanbul,
4sakarya university, sakarya education and research hospital, neurosurgery, sakarya,
DOI: 10.5137/1019-5149.JTN.40697-22.2

Aim:To compare tissue levels of the regulatory enzymes related to the Krebs cycle between low- and high-grade supratentorial gliomas.Material and Methods:A total of 40 patients operated on supratentorial gliomas served as subject for this study. Low-grade and high-grade glioma groups included 19 and 21 patients, respectively. The regulatory enzymes directly involved in the Krebs cycle, namely pyruvate dehydrogenase, citrate synthase, α-ketoglutarate dehydrogenase and isocitrate dehydrogenase and two enzymes that indirectly regulate the Krebs cycle, namely glutamate dehydrogenase and glutaminase were quantitatively studied in tumor tissues by ELISA technique. The results were compared between the two groups.Results:The levels of all enzymes were found to be higher in high-grade glioma group but only pyruvate dehydrogenase, citrate synthase and isocitrate dehydrogenase showed statistical significance. Moreover, all enzymes showed higher tissue levels in grade-II compared to grade-I gliomas but only two enzymes, glutamate dehydrogenase and glutaminase reached significantly higher levels. In high-grade glioma group, all enzymes again showed higher tissue levels in grade-IV gliomas compared to grade-III gliomas, but none showed statistical significance.Conclusion:Regulatory enzymes of the Krebs cycle are increased in high-grade gliomas compared to low-grade gliomas and enzymes of glutaminolysis, namely glutamate dehydrogenase and glutaminase, which are required for resupplying the Krebs cycle, are also increased in order to meet the high energy demand in high-grade gliomas.

Corresponding author : burak tahmazoglu