Influenza infection is estimated to cause one billion annual infections globally. While most infections result in symptoms that are mild and self-resolving, some infections may trigger consequences in the heart including cardiomyocyte death leading to desynchronized contraction. The connection between influenza and cardiovascular conditions has been well documented, however, the mechanisms connecting the respiratory infection to heart function are unclear. “We have known for years that the frequency of heart attacks increases during flu season, yet outside of clinical intuition, scant evidence exists of the underlying mechanisms of that phenomenon,” said senior author Filip Swirski, PhD, director of the Cardiovascular Research Institute at the Icahn School of Medicine at Mount Sinai. Swirski’s team at the Icahn school of Medicine at Mount Sinai aimed to elucidate this connection, studying both human and mouse hearts to clarify the link between influenza infection and cardiac disease. The study is published in a paper titled, “Influenza hijacks circulating myeloid cells to inflict IFN-I-fueled damage in the heart” was published in Immunity. In humans, the team evaluated 35 autopsies of patients who died of influenza while hospitalized. They found that over 85% of these patients had at least one significant cardiovascular comorbidity including hypertension, atherosclerosis, or cardiac fibrosis. They used mice to dive deeper into the mechanisms driving cardiac damage by influenza infection. Mice infected with influenza were observed to have a new type of white blood cell, pro-dendritic cell 3, migrate from the lung to the heart. Once in the heart, the virus escaped…
