Medical Bulletin 04/ July/ 2024

Here are the top medical news for the day:

Study Finds Low-Dose Aspirin May Prevent Pregnancy Complications from Flu Infections

A world-first study, published in the journal Frontiers in Immunology, has found that low-dose aspirin may treat flu-induced blood vessel inflammation, creating better blood flow to the placenta during pregnancy.

Low-dose aspirin, typically 75-100 mg daily, is often used for its anti-inflammatory and blood-thinning properties. It can help prevent blood clots, reduce the risk of heart attacks and strokes, and is sometimes recommended for certain high-risk pregnancies to prevent complications such as preeclampsia.

In the study, animal research examined whether the treatment for preeclampsia could be applied to flu infections, yielding very promising results. Flu infections during pregnancy can resemble preeclampsia, a complication that causes inflammation to the aorta and blood vessels. The research, conducted by RMIT University in collaboration with Trinity College Dublin and the University of South Australia, found that fetuses and placentas from mice with influenza A were smaller than those from uninfected mice. Markers of low oxygen in the blood and poor blood vessel development were also evident in the fetuses.

However, mice treated daily with low-dose aspirin showed less inflammation, improved fetal development, and increased offspring survival. The findings have significant implications for pregnancy and seasonal influenza virus infections. While there aren’t many studies on the impacts of flu infections during pregnancy, it is clear that pregnancy changes how the body responds to the virus.

“When the vascular system is inflamed, it leads to poor blood flow and affects the aorta’s function. This is especially a problem during pregnancy where good blood flow to the placenta is crucial to the development of the fetus. There are long term implications for both the mother and the fetus, and aspirin might provide a simple solution for preventing this influenza associated pathology. This study shines a light, for the first time, on the role of vascular inflammation associated with influenza virus and the potential dramatic effect of the disease-modifying drug aspirin, in low dosage, in pregnant women with co-morbid influenza,” said the authors.

Reference: Coward-Smith M, Liong S, Oseghale O, Erlich JR, Miles MA, Liong F, Brassington K, Bozinovski S, Vlahos R, Brooks RD, Brooks DA, O’Leary JJ and Selemidis S (2024) Low dose aspirin prevents endothelial dysfunction in the aorta and foetal loss in pregnant mice infected with influenza A virus. Front. Immunol. 15:1378610. doi: 10.3389/fimmu.2024.1378610

New Genetic Study Highlights Oxytocin's Role in Treating Obesity and Postnatal Depression

Scientists have identified a gene which, when missing or impaired, can cause obesity, behavioural problems and, in mothers, postnatal depression. The discovery, reported in the journal Cell, may have wider implications for the treatment of postnatal depression, with a study in mice suggesting that oxytocin may alleviate symptoms.

Obesity and postnatal depression are significant global health problems. Postnatal depression affects more than one in 10 women within a year of giving birth and is linked to an increased risk of suicide, which accounts for as many as one in five maternal deaths in high income countries.

Meanwhile, obesity has more than doubled in adults since 1990 and quadrupled in adolescents, according to the World Health Organization.

In the study, scientists from the University of Cambridge, UK, and Baylor College of Medicine, Houston, USA, investigated two boys from different families who exhibited severe obesity, anxiety, autism, and behavioral problems triggered by sounds or smells. They discovered that both boys were missing a single gene known as TRPC5, located on the X chromosome.

TRPC5 is part of a family of genes involved in detecting sensory signals such as heat, taste, and touch. This gene acts on a pathway in the hypothalamus region of the brain, which controls appetite. Detailed examination revealed that TRPC5 acts on oxytocin neurons—nerve cells producing the hormone oxytocin, which is released in response to affection, emotion, and bonding.

Further investigation revealed that the boys inherited the gene deletion from their mothers, who also had the gene missing on one of their X chromosomes. The mothers had obesity and experienced postnatal depression.

To determine if the TRPC5 gene was the cause of the issues in the boys and their mothers, researchers turned to animal models. They genetically engineered mice with a defective version of the gene. Male mice with this defective gene exhibited the same problems as the boys, including weight gain, anxiety, social interaction issues, and aggressive behaviour. Female mice displayed similar behaviours and, as mothers, also showed depressive behaviour and impaired maternal care.

The researchers also found that TRPC5 acts on neurons known for regulating weight. Children with non-functional genes often have an insatiable appetite and gain weight early in life. Although TRPC5 gene deletions are rare, an analysis of DNA samples from around 500,000 individuals in the UK Biobank revealed 369 people with variants of the gene and a higher-than-average body mass index.

The findings suggest that restoring oxytocin could help treat individuals with missing or defective TRPC5 genes and potentially mothers experiencing postnatal depression.

Reference: Li, Y, Cacciottolo, TM & Yin, N. Loss of Transient Receptor Potential Channel 5 Causes Obesity and Postpartum Depression. Cell; 2 July 2024; DOI: 10.1016/j.cell.2024.06.001

Study Links COVID-19 Pandemic to Lower Birth Weights in Indian Infants

The incidence of low birth weight rose sharply in India amid the COVID-19 pandemic, according to new research from the University of Notre Dame.

The study co-authored by Santosh Kumar, associate professor of development and global health economics at Notre Dame’s Keough School of Global Affairs, was published in Communications Medicine, a Nature series journal.

Globally, 1 in 4 newborns has a low birth weight (less than 5.5 pounds), and the problem disproportionately affects low- and middle-income countries — particularly in South Asia, home to approximately one-fourth of the world’s population.

The cross-sectional study used data from 198,203 infants across the country. Researchers used statistical models to compare birth outcomes between two periods: the pandemic period (April 2020-April 2021) and the pre-pandemic period (July 2014-December 2019). They adjusted the models for various factors such as the child's gender and birth order, the mother's age and education, etc.

The study revealed that infants born between April 2020 and April 2021 had lower birth weights compared to those born before the pandemic.

The findings showed that the prevalence of low birth weight increased to 20 percent in the pandemic group, up from 17 percent in the pre-pandemic group. Additionally, infants born during the pandemic weighed approximately four-tenths of an ounce less than their pre-pandemic counterparts.

Several pandemic-related factors may have influenced pregnant women's health behaviours, leading to lower birth weights. These factors include the SARS-CoV-2 virus, stress from social distancing, economic instability, and disruptions in maternal and neonatal care.

“This research shows that low birth weight became more common in India during the pandemic. We saw the exacerbation of a global health problem that affects educational outcomes and poverty rates. Children who have lower birth weight as infants often go on to struggle with school. The study highlights the need for targeted policies that reduce the incidence of low birth weights — for instance, ensuring that women have adequate nutrients and caloric intake during pregnancy and also have access to quality prenatal care,” said Santosh Kumar.

Reference: Kumar, S., Hill, C. & Halliday, T.J. Effects of COVID-19 pandemic on low birth weight in a nationwide study in India. Commun Med 4, 118 (2024). https://doi.org/10.1038/s43856-024-00545-4