Children with Post COVID-19 Multisystem Inflammatory Syndrome Display Unique Pathophysiological Metabolic Phenotypes

Abstract

SARS-CoV-2 infections in children lead to symptoms from mild respiratory illness to severe postacute sequelae of COVID-19, including multisystem inflammatory syndrome in Children (MIS-C). We conducted a metabolic profiling of 147 children's serum samples, including acute COVID-19 patients, MIS-C patients, and healthy controls. Using nuclear magnetic resonance spectroscopy and liquid chromatography-mass spectrometry, we measured 1101 metabolites. The results revealed distinct metabolic profiles in acute COVID-19 and MIS-C patients, with significant alterations in lipid classes. Both conditions exhibited an elevated Apo-B100/Apo-A1 ratio and increased serum inflammatory markers. MIS-C patients showed unique disruptions, including increased triglycerides and altered lipoprotein composition. Despite milder clinical respiratory symptoms, children's metabolic disturbances mirrored those seen in severe adult COVID-19 patients, indicating a shared inflammatory response to SARS-CoV-2. This suggests potential long-term health impacts, underscoring the need for continued research into the metabolic consequences of COVID-19 in children.

Keywords: SARS-CoV-2; hyper-inflammation; inflammation; lipids; lipoproteins; mass spectrometry; nuclear magnetic resonance spectroscopy; phenoconversion.

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Study overview describing participants, analytical analysis, and statistical approach for the three groups.

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Modeling serum samples from children with acute phase SARS-CoV-2 infection using multivariate and supervised analysis: OPLS-DA. (A) Scores of lipoproteins, lipids and low-MW metabolites of COVID-19 affected children and healthy control children (control children: solid green circles (n = 66); SARS-CoV-2 positive children: solid red circles (n = 55)). The MIS-C children were back-projected onto the trained model (MIS-C children open blue circles n = 26). (B) UpSet plot of small molecules and lipoproteins for each group and previously measured Adult group. The number is based on the univariate comparison for each group, with the plot showing the intersection between metabolites’ significance within each group. (C) UpSet plot of the significant lipids for each group and previously measured Adult group. The number is based on the univariate comparison for each group, and the plot shows the intersection between metabolites’ significance within each group. The x axis represents each set (i.e., s1, s2,...) corresponding to a group sharing the same significant metabolite. Where a red filled circle is placed in the corresponding matrix cell to indicate part of an intersection, a light gray circle is shown when not involved in the intersection. Intersections are indicated by the y axis (i.e., groups).

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(A) Selected panel of small molecules and lipoproteins that were significantly different between COVID-19 (red) and MIS-C (blue) patients. Fold changes are calculated relative to the healthy control group. Metabolites are ordered by statistical significance and direction of fold change relative to MIS-C, with the top 10 variables shown in each direction. (B) Lipids measured by mass spectrometry, grouped by lipid class CE (cholesteryl esters), CER (ceramide), DAG/DG (diacylglycerol), DCER (dihydroceramide), FFA (free fatty acids), HCER (hexosylceramide), LCER (lactosylceramide), LPC (lysophosphatidylcholine), LPE (lysophosphatidylethanolamine), LPG (lysophosphatidylglycerol), LPI (lysophosphatidylinositol), MAG/MG (monoacylglycerol), PC (phosphatidylcholine), PE (phosphatidylethanolamine), PG (phosphatidylglycerol), PI (phosphatidylinositol), PS (phosphatidylserine), and SM (sphingomyelin)and ordered by side-chain length and degree of unsaturation. Circle size indicates the magnitude of fold change relative to healthy controls; color indicates group (blue = MIS-C, red = COVID-19). (C) Triglyceride (TAG) species are plotted separately, showing fold change relative to healthy controls. Circle size represents the magnitude of change; colors correspond to group (blue = MIS-C, red = COVID-19).

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Lipoprotein main fraction ApoB100 (=particle number) and ApoA1 (∼particle number) content and lipid composition according to pathology. (A) VLDL ApoB100 distribution between the control cohort (green), COVID-19 (red), and MIS-C (blue). (B) VLDL lipid composition according to the main lipid components of triglycerides (TG, purple), phospholipids (PL, turquoise), cholesterol ester (CE, red), and free cholesterol (FC, green). (C) LDL ApoB100 distribution between control cohort, COVID-19 and MIS-C. (D) LDL lipid composition according to the main lipid components of TG, PL, CE, and FC. (E) HDL ApoA1 distribution between the control cohort, COVID-19, and MIS-C. The ApoA1 content can be used to approximate the HDL particle number. (F) HDL lipid composition according to the main lipid components of TG, PL, CE, and FC.

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Children with COVID-19 and children with MIS-C display abnormal serum lipoproteins. ApoA1 is decreased in acute COVID-19 and MIS-C (A), ApoB100 is increased in MIS-C (B); both cohorts display an increased ApoB100/ApoA1 ratio (C), an established predictive marker of cardiovascular disease. LDL and HDL cholesterol are decreased in acute COVID-19 and MIS-C (D, E), with disrupted supramolecular phospholipid composite (SPC), SPC₃/SPC₂ (F), a surrogate for cardiac disease. Acetylated glycoprotein inflammatory marker (G) GlycA is elevated in both COVID-19 and MIS-C, with reductions in the SPC/Glyc ratio. Each box represents the interquartile range (IQL) for a specific group, with the upper and lower whiskers representing Q3+1.5xIQR and Q1 −1.5xIQR, respectively. Significance values; *p < 0.05; **p < 0.01; ***p < 0.001.