Loss of mitochondrial membrane potential (ΔΨm ) in leucocytes as post-COVID-19 sequelae.

The mitochondrial membrane potential (ΔΨm ) is a parameter often used to determine mitochondrial function; therefore, it can be used to determine the integrity and functionality of cells. A decrement of ΔΨm is implicated in several inflammatory-related pathologies, such phenomena can be related to COVID-19 infection. The present work aimed to compare the ΔΨm in leucocytes (human PBMCs; HPBMC) isolated from healthy control (HC) subjects, patients with COVID-19 (C-19), recovered subjects at 40 ± 13 (R1) and 335 ± 20 (R2) days after infection (dai). Obtained data showed that ΔΨm decreased in HPBMC of subjects with C-19, R1, and R2 compared with HC. When analyzing the ΔΨm data by sex, in females, a significant decrease was observed in R1 and R2 groups versus HC. Regarding men, a significant decrease of ΔΨm was observed in R1, with respect to HC, contrary to R2 group, who reestablished this parameter. Obtained results suggest that the loss of ΔΨm could be related to the long-COVID.

Effect of Fucoidan on the Mitochondrial Membrane Potential (ΔΨm) of Leukocytes from Patients with Active COVID-19 and Subjects That Recovered from SARS-CoV-2 Infection.

Fucoidan is a polysaccharide obtained from marine brown algae, with anti-inflammatory, anti-viral, and immune-enhancing properties, thus, fucoidan may be used as an alternative treatment (complementary to prescribed medical therapy) for COVID-19 recovery. This work aimed to determine the ex-vivo effects of treatment with fucoidan (20 µg/mL) on mitochondrial membrane potential (ΔΨm, using a cationic cyanine dye, 3,3'-dihexyloxacarbocyanine iodide (DiOC6(3)) on human peripheral blood mononuclear cells (HPBMC) isolated from healthy control (HC) subjects, COVID-19 patients (C-19), and subjects that recently recovered from COVID-19 (R1, 40 ± 13 days after infection). In addition, ex-vivo treatment with fucoidan (20 and 50 µg/mL) was evaluated on ΔΨm loss induced by carbonyl cyanide 3-chlorophenylhydrazone (CCCP, 150 µM) in HPBMC isolated from healthy subjects (H) and recovered subjects at 11 months post-COVID-19 (R2, 335 ± 20 days after infection). Data indicate that SARS-CoV-2 infection induces HPBMC loss of ΔΨm, even 11 months after infection, however, fucoidan promotes recovery of ΔΨm in PBMCs from COVID-19 recovered subjects. Therefore, fucoidan may be a potential treatment to diminish long-term sequelae from COVID-19, using mitochondria as a therapeutic target for the recovery of cellular homeostasis.