Researchers discover how severe flu damages the heart

(This is an excerpt from the Health Rounds newsletter, where we report the latest medical research on Tuesdays and Thursdays)

Feb 11 (Reuters) – Researchers believe they now understand how seriously flu cases damage the heart, providing an explanation for the annual increase in heart attacks during flu season.

“We have known for years that the frequency of heart attacks increases during flu season, but outside of clinical intuition, there is little evidence of the mechanisms underlying this phenomenon,” said study leader Filip Swirski of the Icahn School of Medicine at Mount Sinai.

Examining tissue samples from hospitalized patients who died of 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.

Here, instead of doing the usual job of an immune cell to clear the virus, pro-dendritic cell 3 produces large amounts of an inflammatory protein called type 1 interferon (IFN-1), which impairs cardiac output by triggering the death of heart muscle cells.

“Pro-dendritic cell 3 acts as the immune system’s ‘Trojan horse’ during influenza infection, infecting the lung, carrying the virus to the heart, and disseminating it to cardiomyocytes,” study co-author ⁠Jeffrey Downey (also of Mount Sinai) said in a statement.

The flu vaccine provides some protection against this type of heart damage, researchers also report in Immunity.

In laboratory experiments, an mRNA drug that controls IFN-1 activity reduced flu-related heart muscle damage in test tubes and in mice and improved the muscles’ pumping ability, Downey noted.

Swirski said the new findings “hold great promise for the development of new treatments that are urgently needed because there are currently no viable clinical options to prevent heart damage from influenza.”

KEEPING THE UTERUS OUT OF THE WAY OF RADIOTHERAPY

In young women with cancer who need pelvic radiation, surgeons preserve 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 Infertility Reports, Dr. Daniela Huber and Dr. Deborah Wernly describes the first such minimally invasive procedure in Europe that resulted in a live birth in a 28-year-old woman treated for rectal cancer.

To preserve fertility, the so-called uterine and adnexal transposition is performed laparoscopically.

The uterus and its appendages (the ovaries, fallopian tubes, and nearby ligaments known collectively as the adnexa) are lifted to an area above the pelvis and stitched into place. After cancer treatments are completed, the uterus is returned to its original position.

For years, surgeons had been allowing women to preserve their eggs by excluding the ovaries from radiotherapy, but the uterus was left vulnerable to irreparable damage.

Uterine and adnexal transposition was pioneered by surgeons in Brazil and has also been tested by US surgeons.

Huber and Wernly noted that, collectively, the cases so far and the resulting successful births “show that a reimplanted uterus can sustain a pregnancy to term and represent a significant advance for women requiring pelvic radiotherapy.”

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(Reporting by Nancy Lapid; Editing by Bill Berkrot)