Increased ACE2, sRAGE, and immune activation, but lowered calcium and magnesium in COVID-19.

BACKGROUND The characterization of new biomarkers that could help to externally validate the diagnosis of COVID-19 and to optimize treatments is extremely important. Many studies established changes in immune-inflammatory and antibody levels, but few studies measured the soluble receptor for advanced glycation end product (sRAGE), angiotensin-converting enzyme 2 (ACE2), calcium and magnesium in COVID-19. OBJECTIVE To evaluate serum advanced glycation end-product receptor (sRAGE) and angiotensin converting enzyme (ACE)2 and peripheral oxygen saturation (SpO2) and chest CT scan abnormalities (CCTA) in COVID-19. METHODS sRAGE, ACE2, interleukin (IL)-6, IL-10, C-reactive protein (CRP), calcium, magnesium, and albumin were measured in 60 COVID-19 patients and 30 healthy controls. RESULTS COVID-19 is characterized by significantly increased IL-6, CRP, IL-10, sRAGE, ACE2, and lowered SpO2, albumin, magnesium and calcium. COVID-19 with CCTAs showed lower SpO2 and albumin. SpO2 was significantly inversely correlated with IL-6, IL-10, CRP, sRAGE, and ACE2, and positively with albumin, magnesium and calcium. Neural networks showed that a combination of calcium, IL-6, CRP, and sRAGE yielded an accuracy of 100% in detecting COVID-19 patients with calcium being the most important predicter followed by IL-6, and CRP. Patients with positive IgG results showed a significant elevation in the serum level of IL-6, sRAGE, and ACE2 compared to the negatively IgG patient subgroup. CONCLUSION The results show that immune-inflammatory and RAGE pathways biomarkers may be used as external validating criterion for the diagnosis COVID-19. Those pathways coupled with lowered SpO2, calcium and magnesium are drug targets that may help to reduce the consequences of COVID-19.