Researchers believe they now understand how severe cases of influenza damage the heart, providing an explanation for the annual uptick in heart attacks during flu season.
"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,” study leader Filip Swirski of the Icahn School of Medicine at Mount Sinai said in a statement.
Studying tissue samples from hospitalized patients who died of influenza, the researchers learned that a type of immune cell known as a pro-dendritic cell 3 becomes infected in the lungs and travels to the heart.
There, instead of performing an immune cell's usual job of clearing the virus, the pro-dendritic cell 3 produces large amounts of an inflammatory protein called type 1 interferon (IFN-1) that triggers the death of heart muscle cells, impairing cardiac output.
"The pro-dendritic cell 3 acts as the ‘Trojan horse’ of the immune system during influenza infection, becoming infected in the lung, trafficking the virus to the heart, and disseminating it to cardiomyocytes,” study co-author Jeffrey Downey, also from Mount Sinai, said in a statement.
Vaccination against the flu offers some protection against this type of heart damage, the researchers also reported in Immunity.
Downey noted that in lab experiments, an mRNA drug that controls IFN-1 activity reduced the influenza-related heart muscle damage in test tubes and in mice and improved the muscles’ pumping ability.
The new findings "offer great promise for the development of new therapies, which are desperately needed since there are currently no viable clinical options to prevent cardiac damage” from the flu, Swirski said.
In young women with cancer who need pelvic radiation, surgeons are preserving their ability to give birth in the future by temporarily moving the uterus out of the path of the high-energy radio waves, Swiss researchers report.
Writing in Fertility and Sterility Reports, Dr. Daniela Huber and Dr. Deborah Wernly of Valais Hospital in Sion, Switzerland, describe the first such minimally invasive procedure in Europe to result in a live birth, in a woman who had been treated for rectal cancer at age 28.
So-called uterine and adnexal transposition for fertility preservation is done laparoscopically.
The uterus and its appendages – the ovaries, fallopian tubes and nearby ligaments, collectively known as the adnexa – are lifted to a region above the pelvis and stitched into place. After the cancer treatments are completed, the uterus is restored to its original position.
For years, surgeons have been moving the ovaries out of the way of radiotherapy, allowing women to preserve their eggs, but the uterus remained vulnerable to irreparable damage.
Uterine and adnexal transposition was pioneered by surgeons in Brazil and has also been tested by U.S. surgeons.
Collectively, the cases done so far and the successful births that resulted "demonstrate that a re-implanted uterus can sustain gestation to term, representing a significant advance for women requiring pelvic radiotherapy,” Huber and Wernly concluded.
