Lactate dehydrogenase, a Risk Factor of Severe COVID-19 Patients

Yi Han; Haidong Zhang; Sucheng Mu; Wei Wei; Chaoyuan Jin; Yuan Xue; Chaoyang Tong; Yunfei Zha; Zhenju Song; Guorong Gu

LDH is found in all human cells, especially in myocardial and liver cells. In our study, LDH elevation was positively associated with AST, cTnI and BNP, which verified it as an isozyme of heart and liver. However, it was somewhat surprising that cTnI was neither associated with PSI nor CT semiquantitative score, while was relevant with disease severity. Similarly, BNP that had a strong correlation with APACHE II and SOFA, was not associated with CT semiquantitative score, either. Furthermore, AST which was associated with the APACHE II and SOFA score, was not related to PSI score. This rather intriguing finding might be explained by the fact that the myocardial and liver injury caused by SARS-CoV-2 might be due to the direct damage of the virus to targeted organs, while not because of hypoxia induced by lung injury. Since the outbreak of COVID-19, structural analysis of the virus has suggested that SARS-CoV-2 might be able to bind to the angiotensin-converting enzyme 2 (ACE2) receptor in humans(16, 17). The ACE2 receptor is abundantly present in the epithelia of lung and small intestine(18), which might provide possible routes of entry for SARS-CoV-2.