Serum Calcitonin Gene-Related Peptide α and β Levels are Increased in COVID-19 Inpatients.

BACKGROUND: Vasoactive peptides play an important role in a wide range of physiological and pathological conditions. Due to its known functions, the calcitonin gene-related peptide (CGRP) has been suggested as a possible modulator of the hyperimmune response in COVID-19 and thus, blocking its action may lessen the pulmonary effects of COVID-19.

AIM OF THE STUDY: To compare the circulating levels of CGRPα and CGRPβ in healthy controls compared to hospitalized COVID-19 patients. The study also analyzed how different comorbidities and treatments may affect these concentrations in cases of COVID-19 infection with pulmonary involvement METHODS: Serum samples were collected from the antecubital vein of 51 control subjects (mean age = 55 ± 14 years; range = 26-77; 56.9% female) and 52 patients hospitalized with COVID-19 infection (mean age = 55 ± 13; range = 23-77; 55.8% female) from December 2020 to May 2021. Enzyme-linked immunosorbent assays (ELISAs) were used for CGRPα (Abbexa, UK) and CGRPβ (CUSABIO, China) measurements. Comorbidities, symptoms, and treatments of infection were listed.

RESULTS: The results showed that the serum levels of both isoforms of CGRP were significantly higher in patients with COVID-19 (α: 57.9 ± 35.8 pg/mL; β: 6.1 ± 2.6 pg/mL) compared to controls (α: 41.8 ± 25.4 pg/mL; β: 4.5 ± 2.4 pg/mL) (p <0.01). Also, the presence of arterial hypertension (HT), obesity, or corticosteroid treatment significantly alter the serum concentration of CGRPα in the subgroups compared to controls.

CONCLUSION: The elevated serum CGRP levels found in our COVID-19 group compared to controls may suggest that CGRP plays a role in the pathophysiology of the disease, more specifically, in the cytokine storm and in the pulmonary involvement. Future studies should focus on the source of this CGRP elevation.