Medical Bulletin 13/Jun/2025

New Delhi: In a study published in Nature Communications, scientists from the University of Southern California (USC) have identified a specific group of brain cells that may explain why people with memory problems are more prone to overeating. The research reveals that certain neurons in the brain’s ventral hippocampus are responsible for forming "meal engrams"—specialized memory traces that store detailed information about eating events.

The study sheds light on the connection between memory and hunger, suggesting that remembering what and when we eat may play a key role in regulating appetite. The findings may help explain why individuals with memory impairments, such as those with Alzheimer’s disease, often struggle with disordered eating behaviors.

To uncover these findings, researchers used advanced neuroscience tools to observe brain activity in laboratory rats in real time as they consumed food. They found that meal-related memory neurons activated during eating and were distinct from neurons involved in other types of memory, such as spatial navigation. When these specific neurons were selectively destroyed, rats lost the ability to remember food locations but could still perform other memory tasks. This suggests the brain may have a dedicated system for processing meal-related memories.

The team also identified a critical connection between the ventral hippocampus and the lateral hypothalamus, the brain region responsible for regulating hunger. When this neural pathway was disrupted, rats not only failed to remember their last meal but also began overeating, highlighting the importance of memory in appetite control.

“Our work shows that memory isn’t just about the past—it plays a crucial role in shaping eating behavior and regulating hunger,” said Professor Scott Kanoski, senior author of the study.

Reference: Léa Décarie-Spain, Cindy Gu, Logan Tierno Lauer, Keshav S. Subramanian, Samar N. Chehimi, Alicia E. Kao, Serena X. Gao, Iris Deng, Alexander G. Bashaw, Molly E. Klug, Jessica J. Rea, Alice I. Waldow, Ashyah Hewage Galbokke, Olivia Moody, Kristen N. Donohue, Mingxin Yang, Guillaume de Lartigue, Kevin P. Myers, Richard C. Crist, Benjamin C. Reiner, Matthew R. Hayes, Scott E. Kanoski. Ventral hippocampus neurons encode meal-related memory. Nature Communications, 2025; 16 (1) DOI: 10.1038/s41467-025-59687-1

New Delhi: A clinical trial may enhance how medical professionals detect hidden blood clots responsible for strokes. The study, published in The Lancet Neurology, is the first to show that extending imaging to include the heart within minutes of a patient’s arrival to hospital with an acute stroke significantly improves the ability to determine the stroke’s underlying cause. This innovative diagnostic approach can be used to determine an effective and tailored treatment plan for preventing future strokes.

Strokes caused by blood clots or other mechanisms that obstruct blood flow in the brain account for about 85 per cent of all strokes. In this study, scientists set out to determine whether strokes with undetermined causes could be identified using computed tomography (CT) scans that include images of the heart and aorta, a main blood vessel.

The clinical trial included 465 patients admitted to London Health Sciences Centre’s University Hospital who were treated for an acute stroke or transient ischemic attack. The study found that using the extended CT scan increased the detection of blood clots in the heart by 500 per cent compared to standard imaging practice. They also found the extended CT scan did not delay completion of CT imaging in these emergency situations. The study found one clot for every 14 patients scanned with the new approach.

“If we did not extend the CT scan, some of these blood clots may not have been found and these strokes would have been classified as having an undetermined cause,” says Dr. Rodrigo Bagur, researcher at LHSCRI, Cardiologist at LHSC, and Professor at Schulich Medicine & Dentistry.

Reference: Extended CT angiography versus standard CT angiography for the detection of cardioaortic thrombus in patients with ischaemic stroke and transient ischaemic attack (DAYLIGHT): a prospective, randomised, open-label, blinded end-point trial, Sposato, Luciano A et al., The Lancet Neurology, Volume 24, Issue 6, 489 - 499

Vitamin D May Help Slow Down Aging: Study Finds

New Delhi: A new study published in The American Journal of Clinical Nutrition suggests that taking vitamin D supplements could help slow down biological aging at the cellular level. The study found that vitamin D may protect chromosome ends—called telomeres—from shortening, a process closely tied to aging and age-related diseases.

Telomeres are protective caps located at the ends of chromosomes that naturally wear down as we age. When they become too short, cells can no longer divide effectively, leading to cellular aging and a higher risk of conditions such as heart disease and cancer. The shorter your telomeres, the more biologically “aged” your cells are thought to be.

The research team examined data from the long-running VITAL study, a randomized clinical trial involving more than 1,000 participants—women aged 55 and older and men aged 50 and above. Participants were randomly assigned to take either vitamin D3 (2,000 IU/day), omega-3 fatty acids (1 g/day), or a placebo over a span of up to four years. This telomere-focused sub-study specifically aimed to observe whether these supplements could influence the rate of telomere shortening.

The results were promising: individuals who took vitamin D experienced significantly less telomere shortening than those given a placebo. In fact, vitamin D supplementation appeared to slow cellular aging by nearly three years’ worth of telomere decline. Interestingly, omega-3 supplements did not show a similar effect in preserving telomere length.

“VITAL is the first large-scale and long-term randomized trial to show that vitamin D supplements protect telomeres and preserve telomere length,” said co-author JoAnn Manson, principal investigator of VITAL. “This is of particular interest because VITAL had also shown benefits of vitamin D in reducing inflammation and lowering risks of selected chronic diseases of aging.”

Reference: https://news.harvard.edu/gazette/story/2025/05/vitamin-d-supplements-may-slow-biological-aging/