GC–MS Identifies Metabolites Triggering Inflammation in COVID-19 Patients

A collaboration between researchers at the Sichuan Mianyang 404 Hospital in Mianyang, Sichuan, China between January and May 2020, published in the journal Chromatographia, utilized gas chromatography–mass spectrometry (GC–MS) to try to identify the inflammatory mechanism of the virus that causes COVID-19 (1).

Coronavirus Covid-19 background - 3d rendering | Image Credit: © Production Perig - stock.adobe.com

In the earliest months of the SARS-CoV-2 pandemic, differential metabolites in the serum of 15 COVID-positive patients and a control group at Sichuan Mianyang 404 Hospital were analyzed with GC–MS non-targeted metabolomics to gauge the level of inflammatory response in those with the disease. Separately, flow cytometry was used to detect distribution of lymphocytes and subpopulations in peripheral whole blood to assess patients’ immune function.

The 15 COVID patients were divided into groupings of common and severe cases. Common cases, of which there were 11, were typified by upper respiratory tract infection symptoms like low-to moderate-grade fever, dry or sore throat, congested or runny nose, or pneumonia indicated by imaging. Severe cases, from which four of the patients suffered, satisfied at least one of four qualifications: shortness of breath, oxygen saturation in resting state, arterial blood partial pressure of oxygen, or lung imaging showing lesions within 24 hours.

Taking the differentiation in cases into account, deployment of GC–MS non-targeted metabolomics was considered by the researchers to be an improvement in identifying both the mechanism and severity of COVID-19 compared to either nucleic acid or specific antibody testing.

Regarding the metabolites detected in the COVID-positive patients, 53 were upregulated, 18 were downregulated, and 8 were unchanged. Varying degrees of increase were found in hypersensitive C reactive protein (hs CRP), certain interleukin receptors (IL-5/6/8/10), and interferon-alpha (IFN-α), while it was noted that CD3/4/8⁺ T lymphocytes decreased.

CD3/4/8⁺ T lymphocytes are a type of white blood cell involved in the immune system's defense against infections and cancer. They are responsible for recognizing and eliminating foreign pathogens and abnormal cells in the body. These T cells play a crucial role in coordinating the immune response and regulating other immune cells.

From those results, the researchers concluded that combined increases in cholesterol, lactic acid, and 1-monopalmitin could be the mechanism causing increased inflammation. Additionally, there may be a link between the increase in D-allose and the decrease in lymphocytes.

But aside from detecting this “severe storm of inflammatory factors” in COVID-19 patients, researchers hope that metabolomics, using GC–MS, can be further used to identify biomarkers to assess the progression of the disease, and the development of therapeutics.

Reference

(1) Chen, X.; Gu, X.; Yang, J.; Jiang, Z.; Deng, J. Gas Chromatography–Mass Spectrometry Technology: Application in the Study of Inflammatory Mechanism in COVID-19 Patients. Chromatographia 2023, 86, 175-183. DOI: 10.1007/s10337-022-04222-3