Background: COVID-19 impacts the cardiovascular system resulting in myocardial damage, and also affects the kidneys leading to renal dysfunction. This effect is mostly through the binding with angiotensin-converting enzyme 2 (ACE2) and Neuropilin-1 (NRP-l) receptors. Toll-Like Receptors (TLRs) typically combine with microbial pathogens and provoke an inflammatory response.
Aim: This work aims to compare the changes in kidney and heart function bioindicators and expressions of TLRs (TLR2 and TLR2) as well as ACE2 and NRP-l receptors in moderate and severe COVID-19 patients. The correlations between kidney and heart function bioindicators and expressions of these receptors are also studied.
Patients and methods: In this study, 50 healthy control and 100 COVID-19 patients (55 males and 45 females) were enrolled. According to WHO guidelines, these participants were divided into severe (50 cases) and moderate (50 cases). Serum creatinine, blood urea, CK-MB, LDH, and Troponin I were estimated. We measured the gene expression for Toll-Like Receptors (TLR2 and TLR4), ACE2, and NRP-1 in the blood samples using quantitative real-time PCR (qRT-PCR).
Results: In comparison with the healthy group, all patients exhibited a significant elevation in serum creatinine, urea, cardiac enzymes (CK-MB and LDH), and CRP. Serum Troponin I level was significantly increased in severe COVID-19 patients. Furthermore, all studied patients revealed a significant elevation in the expression levels of TLR2, TLR4, ACE2, and NRP-1 mRNA. In all patients, CK-MB, ACE2, and NRP-1 mRNA expression levels were positively correlated with both TLR2 and TLR4 expression levels. Moreover, serum creatinine and urea levels were positively correlated with both TLR2 and TLR 4 expression levels in the severe group only. In the moderate group, serum CK-MB activity and Troponin I level had a significant positive correlation with both NRP-1 and ACE2 expression levels, while serum urea level and LDH activity had a significant positive correlation with NRP-1 only. In severe patients, the increases in serum creatinine, urea, CK-MB, and LDH were significantly associated with the elevations in both ACE2 and NRP-1 expression levels, whereas serum Troponin I level had a positive direct relationship with NRP-1 only.
Conclusions: Our study concluded that expression levels for TLR2, TLR4, ACE2, and NRP-1 mRNA in both severe and moderate patients were positively correlated with renal biomarkers and cardiac enzymes. Innate immune markers can be important because they correlate with the severity of illness in COVID-19.
Keywords: ACE2; COVID-19; NRP-1; TLRs; cardiac enzymes; renal function.