(This is an excerpt from the Health Rounds newsletter, where we present the latest medical studies on Tuesdays and Thursdays)
Feb 11 (Reuters) – Researchers believe they now understand how severe cases of influenza damage the heart, providing an explanation for the annual increase in heart attacks during flu season.
“For years we have known that the frequency of heart attacks increases during flu season, but outside of clinical intuition, there is scant evidence 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 the flu, researchers learned that a type of immune cell known as pro-dendritic cell 3 becomes infected in the lungs and travels to the heart.
There, instead of carrying out the usual work of an immune cell that clears the virus, the pro-dendritic cell 3 produces large amounts of an inflammatory protein called interferon type 1 (IFN-1) that triggers the death of heart muscle cells, which impairs cardiac output.
“Pro-dendritic cell 3 acts as the ‘Trojan horse’ of the immune system during influenza infection, infecting the lung, trafficking the virus to the heart, and distributing it to cardiomyocytes,” study co-author Jeffrey Downey, also of Mount Sinai, said in a statement.
The flu vaccine offers some protection against this type of heart damage, the researchers also reported in Immunity.
Downey noted that in laboratory experiments, an mRNA drug that controls IFN-1 activity reduced flu-related heart muscle damage in test tubes and mice and improved the muscle’s pumping capacity.
The new findings “offer great promise for the development of new therapies, which are desperately needed, as there are currently no viable clinical options to prevent cardiac damage” from the flu, Swirski said.
MOVE THE UTERUS OUT OF THE PATH OF RADIOTHERAPY
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 high-energy radio waves, Swiss researchers report.
Writing in Fertility and Sterility Reports, Dr. Daniela Huber and Dr. Deborah Wernly of the Valais Hospital in Sion, Switzerland describe the first such minimally invasive procedure in Europe resulting in a live birth, in a woman who had been treated for rectal cancer at the age of 28.
The so-called transposition of the uterus and adnexa for the preservation of fertility is performed laparoscopically.
The uterus and its appendages – the ovaries, fallopian tubes and nearby ligaments, known collectively as the adnexa – are removed in a region above the pelvis and sewn in place. After the cancer treatments are completed, the uterus returns 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 has remained vulnerable to irreparable damage.
Uterine and adnexal transposition was pioneered by surgeons in Brazil and has also been tested by surgeons in the United States.
Collectively, the cases performed so far and the resulting successful births “demonstrate that a reimplanted uterus can sustain a pregnancy to term, which represents a significant advance for women requiring pelvic radiotherapy,” Huber and Wernly concluded.
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(Reporting by Nancy Lapid; Editing by Bill Berkrot)