Age is a key risk factor for morbidity in coronavirus disease 2019 (COVID-19). This study investigates how "inflammaging" predisposes older hosts to severe SARS-CoV-2 outcomes through systemic and localized metabolic shifts. SARS-CoV-2 infection experiments were conducted respectively on 8 week-old mice and 16 week-old mice. An integrated multiomics approach was employed to delineate age-dependent molecular signatures and metabolic-immune crosstalk. 16 week-old mice exhibited significantly exacerbated weight loss and pulmonary pathology, successfully recapitulating age-related susceptibility. Multiomics integration revealed a "systemic bioenergetic gap": suppressed plasma TCA cycle metabolites correlated with depleted pulmonary nucleotide pools (AMP, GMP, UMP and uracil). This metabolic failure led to a paradoxical proteomic profile: despite interferon pathway activation, key antiviral effectors (RSAD2, ISG15, IFIT3B) were downregulated, while stress markers (CYP1A1, MAPK8) increased. Furthermore, threonic acid, betaine, and d-ribose were identified as robust, age-dependent biomarkers of infection severity. Our findings suggest that COVID-19 severity in the aging host is driven by the failure of a systemic-to-local metabolic-immune axis. The exhaustion of circulating energetic precursors constrains localized pulmonary nucleotide metabolism, thereby impairing essential antiviral responses and tissue repair. This study identifies the "systemic bioenergetic gap" as a novel therapeutic target, suggesting that systemic metabolic resuscitation may improve clinical outcomes in elderly populations.
Li et al. (Mon,) studied this question.