A late-stage multi-dimensional intervention rescues lethal viral pneumonia in an aged hamster model

Abstract

Severe pneumonia caused by respiratory virus infection is one of the main threats to the lifespan of the aged population and physiological aging fundamentally drives poor disease outcomes in respiratory viral infections, necessitating investigation of the underlying mechanisms and the development of effective countermeasures. Pulmonary transcriptomic profiling reveals that diffuse cell death, inadequate antiviral responses, myeloid-driven excessive inflammation and immune-thrombosis dictate the pulmonary microenvironment are typical molecular pathology characteristics of the SARS-CoV-2-infected aged hamsters rather than the adult controls. The elevated pathological baseline and dysregulated immune responses are demonstrated as the key host factors of lethal viral pneumonia in the aged hamsters. Meanwhile, SARS-CoV-2 infection in the adult hamsters usually resulted in an aged-like pulmonary transcriptomic signature, suggesting a potential link among aging, dysregulated immune responses and severe illness. To reverse the progression of lethal severe pneumonia in the aged hamsters, we initiated a multidimensional combination therapy of dexamethasone, heparin and the broad-spectrum viral decoy CoVR-MV at three days after infection. Although single- and dual-drug therapies were insufficient to achieve functional cure, the three-drug combination therapy resulted in a potent reduction of high mortality, body weight loss, viral load, lung pathology and cytokine storm through the synergism of immunoregulatory, anticoagulant and antiviral effects, effectively intercepting the multifaceted pathogenic network. This study highlights physiological aging as a core driver of critical COVID-19 pathogenesis and provides valuable clues for the rational design of multi-drug and multi-target therapies against respiratory viral infections and lethal severe pneumonia in the elderly population.