Abstract
•Covid-19 patients have a decrease in hemoglobin levels and an increase in PpIX levels.•SARS-Cov-2 depends on iron to replicate within living host cells.•SARS-Cov-2 obtains iron from hemoglobin and heme.•Once disrupted, heme releases PpIX.•PpIX fluorescence could be employed on the Covid-19 diagnosis or as a marker to monitor the response to the treatments. Therapies using exogenous porphyrins or endogenous PpIX could be employed for Covid-19 treatment.
SARS-CoV-2 attacks hemoglobin through its structural protein ORF3a, dissociating the iron from the heme, as iron is necessary by cell machinery for virus replication. In this process protoporphyrin (PpIX) is released.
The decrease in the hemoglobin levels observed in patients with Covid-19 is frequently accompanied by an increase in PpIX levels. This evidence was confirmed by the quantification of PpIX by high-performance liquid chromatography (HPLC). PpIX emission is observed in its two characteristic bands at approximately 635 nm and 705 nm.
This paper searches to understand the role of heme and PpIX inside the cells. Perspectives on the use of PpIX fluorescence as a sensor to monitor the presence of SARS-CoV-2 in the tissue, blood, urine, or feces to map the evolution and severity of the disease or to monitor the response of the Covid-19 treatment modalities were described.
Fluorescence spectroscopy could be adopted as an excellent diagnostic technique for Covid-19, of low cost and high sensitivity. This method can potentially be used as a marker to monitor the response to the treatments. Photodynamic and sonodynamic therapies using the endogenous PpIX increased in the acute phase of the disease, could be employed for Covid-19 treatment.