Are dysregulated metabolism and inflammation contributing factors to the ongoing symptoms in long-term COVID-19 syndrome patients?

NewsGuard 100/100 Score

In a recent study posted to bioRxiv*, researchers reported that dysregulation in energy metabolism and inflammation could contribute to long-term coronavirus disease 2019 (COVID-19) syndrome (LTCS).

Study: Maintained imbalance of triglycerides, apolipoproteins, energy metabolites and cytokines in long-term COVID-19 syndrome (LTCS) patients. Image Credit: fizkes/Shutterstock
Study: Maintained imbalance of triglycerides, apolipoproteins, energy metabolites and cytokines in long-term COVID-19 syndrome (LTCS) patients. Image Credit: fizkes/Shutterstock

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources

Background

Numerous studies have uncovered the role of metabolites in COVID-19. Specifically, peripheral blood mononuclear cells (PBMCs) show dysregulation of glycolysis and oxidative phosphorylation, with increased lactate and reduced glucose levels in COVID-19 patients. Therefore, identifying metabolites in blood would provide a picture of the pathophysiological state of the disease.

Several COVID-19 patients develop LTCS following the acute phase, with symptoms like dyspnea, chronic fatigue, and brain fog, among others. Mitochondrial dysfunction, impaired interleukin (IL)-10 production, and fatty acid metabolism have been reported in LTCS individuals. Therefore, the role of inflammation and metabolism during LTCS progression warrants further investigation.

About the study

In the present study, researchers performed an integrated analysis of blood serum/plasma using the in vitro diagnostics research nuclear magnetic resonance (NMR) analytical platform and cytokine measurements in COVID-19 patients, recovered individuals, LTCS patients, and healthy controls. All participants were aged 18 or older. LTCS subjects were recruited only if samples were collected more than 28 days after testing positive for COVID-19.

Initially, samples were collected for DNA isolation for whole genomic and epigenetic analyses, and leftover surplus blood was used for analysis in the current study. Plasma was isolated from blood samples and tested for inflammatory cytokine levels using a 13-plex flow cytometry-based assay, which permits simultaneous measurement of 13 cytokines and chemokines. Data were analyzed automatically and manually by standard curve detection.

In the automatic gating strategy, two sets of beads were used, each with a unique size that can be identified by the side (SSC) and forward (FSC) scatter profiles. Raw NMR spectra were recorded for blood samples. Five one-dimensional 1H-NMR experiments were performed for each sample. Nuclear Overhauser effect spectroscopy (NOESY) was performed to show NMR spectrum quality and enable estimation of metabolites and high molecular weight compounds. 

Findings

In total, 125 individuals were recruited. Controls were significantly younger than recovered individuals, while the age of LTCS, COVID-19 patients, and recovered individuals was not significantly different. Males and females were equally represented in controls and LTCS patients. Samples were collected after a median of 152 and 128 days after infection from LTCS patients and recovered individuals, respectively.

LTCS patients reported fatigue, dyspnea, dizziness, anosmia, ageusia, anxiety, myalgia, neuropathy, and headache. Creatine (amino acid) and 3-hydroxybutyrate (a ketone body) were the highest in the plasma of COVID-19 patients; histidine and citrate were the highest in LTCS samples, and lactate and pyruvate were the highest in the recovered subjects. Moreover, LTCS subjects had higher acetone, citrate, and formate levels than recovered individuals.  

The authors mostly focused on comparisons between LTCS subjects and controls, as samples from COVID-19 patients and recovered subjects were limited. As such, a supervised classification model was built to differentiate between controls and LTCS individuals. This revealed heightened levels of lactate, pyruvate, alanine, and methionine in LTCS patients relative to controls.

In LTCS subjects, 18 and 38 lipoproteins were increased and decreased, respectively, relative to controls. Blood triglycerides were higher in COVID-19 patients, recovered, and LTCS subjects than in controls. Very low-density lipoprotein (VLDL) phospholipids were also higher in LTCS and recovered subjects. COVID-19 patient samples showed the highest levels of cytokines and chemokines than other groups.

Most cytokines and chemokines were in lower levels among LTCS and recovered individuals than in controls, except IL-18, which was higher in LTCS and recovered subjects. IL-6, IL-10, and IL-18 were abundant in COVID-19 patient samples. Correlation analyses revealed that COVID-19 patients had the highest levels of cytokines, whereas LTCS subjects had low levels of cytokines and chemokines.

Histidine was highly enriched in LTCS samples. Histidine, phenylalanine, and ketone bodies increased with the deterioration of health. COVID-19 patients had a strong positive correlation to glycerides, 2-oxoglutaric acid, succinate, acetoacetate, 3-hydroxybutyrate, and a negative correlation towards high-density lipoprotein (HDL) free cholesterol and phospholipids.

Conclusions

In summary, the researchers identified dysregulation of several metabolites, cytokines, and lipoprotein in LTCS patients than in other groups. Notably, relative to controls, pyruvate, and lactate were highly elevated in LTCS individuals. Glycine, phenylalanine, creatinine, glutamine, and acetate were downregulated in LTCS samples. Blood levels of phenylalanine, formate, creatine, pyruvate, and ketone bodies may indicate increased LTCS severity. Together, the findings provided novel insights into metabolomic, lipoprotein, and inflammation changes in LTCS subjects.

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources

Journal references:

Article Revisions

  • May 17 2023 - The preprint preliminary research paper that this article was based upon was accepted for publication in a peer-reviewed Scientific Journal. This article was edited accordingly to include a link to the final peer-reviewed paper, now shown in the sources section.
Tarun Sai Lomte

Written by

Tarun Sai Lomte

Tarun is a writer based in Hyderabad, India. He has a Master’s degree in Biotechnology from the University of Hyderabad and is enthusiastic about scientific research. He enjoys reading research papers and literature reviews and is passionate about writing.

Citations

Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Sai Lomte, Tarun. (2023, May 17). Are dysregulated metabolism and inflammation contributing factors to the ongoing symptoms in long-term COVID-19 syndrome patients?. News-Medical. Retrieved on May 29, 2024 from https://www.news-medical.net/news/20230119/Are-dysregulated-metabolism-and-inflammation-contributing-factors-to-the-ongoing-symptoms-in-long-term-COVID-19-syndrome-patients.aspx.

  • MLA

    Sai Lomte, Tarun. "Are dysregulated metabolism and inflammation contributing factors to the ongoing symptoms in long-term COVID-19 syndrome patients?". News-Medical. 29 May 2024. <https://www.news-medical.net/news/20230119/Are-dysregulated-metabolism-and-inflammation-contributing-factors-to-the-ongoing-symptoms-in-long-term-COVID-19-syndrome-patients.aspx>.

  • Chicago

    Sai Lomte, Tarun. "Are dysregulated metabolism and inflammation contributing factors to the ongoing symptoms in long-term COVID-19 syndrome patients?". News-Medical. https://www.news-medical.net/news/20230119/Are-dysregulated-metabolism-and-inflammation-contributing-factors-to-the-ongoing-symptoms-in-long-term-COVID-19-syndrome-patients.aspx. (accessed May 29, 2024).

  • Harvard

    Sai Lomte, Tarun. 2023. Are dysregulated metabolism and inflammation contributing factors to the ongoing symptoms in long-term COVID-19 syndrome patients?. News-Medical, viewed 29 May 2024, https://www.news-medical.net/news/20230119/Are-dysregulated-metabolism-and-inflammation-contributing-factors-to-the-ongoing-symptoms-in-long-term-COVID-19-syndrome-patients.aspx.

Comments

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
Post a new comment
Post

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.

You might also like...
Study shows enforced masking on long flights prevents SARS-CoV-2 transmission