Abstract:
Background One of the major challenges currently faced by global health systems is the prolonged COVID-19 syndrome (also known as “long COVID”) which has emerged as a consequence of the SARS-CoV-2 epidemic. The World Health Organization (WHO) recognized long COVID as a distinct clinical entity in 2021. It is estimated that at least 30% of patients who have had COVID-19 will develop long COVID. This has put a tremendous strain on still-overstretched healthcare systems around the world.
Methods In this study, our goal was to assess the plasma metabolome in a total of 108 samples collected from healthy controls, COVID-19 patients, and long COVID patients recruited in Mexico between 2020 and 2022. A targeted metabolomics approach using a combination of LC-MS/MS and FIA MS/MS was performed to quantify 108 metabolites. IL-17 and leptin concentrations were measured in long COVID patients by immunoenzymatic assay.
Results The comparison of paired COVID-19/post-COVID-19 samples revealed 53 metabolites that were statistically different (FDR < 0.05). Compared to controls, 29 metabolites remained dysregulated even after two years. Notably, glucose, kynurenine, and certain acylcarnitines continued to exhibit altered concentrations similar to the COVID-19 phase, while sphingomyelins and long saturated and monounsaturated LysoPCs, phenylalanine, butyric acid, and propionic acid levels normalized. Post-COVID-19 patients displayed a heterogeneous metabolic profile, with some showing no symptoms while others exhibiting a variable number of symptoms. Lactic acid, lactate/pyruvate ratio, ornithine/citrulline ratio, sarcosine, and arginine were identified as the most relevant metabolites for distinguishing patients with more complicated long COVID evolution. Additionally, IL-17 levels were significantly increased in these patients.
Conclusions Mitochondrial dysfunction, redox state imbalance, impaired energy metabolism, and chronic immune dysregulation are likely to be the main hallmarks of long COVID even two years after acute COVID-19 infection.
Source: Yamilé López-Hernández, Joel Monárrez Aquino, David Alejandro García López, Jiamin Zheng, Juan Carlos Borrego, Claudia Torres-Calzada, José Pedro Elizalde-Díaz, Rupasri Mandal, Mark Berjanskii, Eduardo Martínez-Martínez, Jesús Adrián López, David S. Wishart. The plasma metabolome of long COVID-19 patients two years after infection. doi: https://doi.org/10.1101/2023.05.03.23289456 (Full text)