Medical Bulletin 23/February/2024

Here are the top medical news highlights for the day:

New study finds unique brain organization patterns in males and females

A new study conducted by researchers at Stanford Medicine revealed an advanced artificial intelligence model that boasts over 90% accuracy in discerning whether brain activity scans belong to a woman or a man.

The findings published Feb. 19 2024 in the Proceedings of the National Academy of Sciences, helped resolve a long-term discussion about whether reliable sex differences exist in the human brain and suggest that understanding these differences may be critical to addressing neuropsychiatric conditions that affect women and men differently.While sex chromosomes determine hormone exposure, linking sex to distinct brain differences has been challenging. Brain structures appear similar in both genders and studies on brain region interactions have not consistently revealed sex-related indicators.

"A key motivation for this study is that sex plays a crucial role in human brain development, in ageing, and in the manifestation of psychiatric and neurological disorders," said Vinod Menon, PhD, professor of psychiatry and behavioural sciences and director of the Stanford Cognitive and Systems Neuroscience Laboratory. "Identifying consistent and replicable sex differences in the healthy adult brain is a critical step toward a deeper understanding of sex-specific vulnerabilities in psychiatric and neurological disorders."

The "hotspots" crucial for distinguishing between male and female brains in the model include the default mode network, responsible for processing self-referential information, and the striatum and limbic network, associated with learning and reward response.

For the study, Menon and his team analysed recent AI advancements and extensive datasets. They developed a deep neural network model capable of classifying brain imaging data. By presenting brain scans as male or female to the model, it learned to discern subtle patterns for differentiation.The model employed a deep neural network to analyse dynamic MRI scans, capturing the complex interactions among various brain regions. During testing on approximately 1,500 brain scans, it consistently distinguished between scans from women and men with remarkable accuracy.

The model's success suggested that detectable sex differences do exist in the brain thathave not been studied previously. "This is a very strong piece of evidence that sex is a robust determinant of human brain organization," concluded Menon.

References: Srikanth Ryali, Yuan Zhang, Carlo de los Angeles, Kaustubh Supekar, Vinod Menon. Deep learning models reveal replicable, generalizable, and behaviorally relevant sex differences in human functional brain organization. Proceedings of the National Academy of Sciences, 2024; 121 (9) DOI: 10.1073/pnas.2310012121

Hair loss and prostate medication may decrease heart disease risk in men

A study published in the Journal of Lipid Research by University of Illinois researchers revealed strong links between finasteride usage and reduced cholesterol levels in men.

The drug finasteride, also known as Propecia or Proscar, treats male pattern baldness and enlarged prostate in millions of men worldwide.It works by blocking the 5-alpha reductase 2 protein found in hair follicles and the prostate gland that activates testosterone.

"When we looked at the men taking finasteride in the survey, their cholesterol levels averaged 30 points lower than men not taking the drug. I thought we'd see the opposite pattern, so it was very interesting," said lead study author Jaume Amengual, assistant professor in the Department of Food Science and Human Nutrition and the Division of Nutritional Sciences, both part of the College of Agricultural, Consumer and Environmental Sciences (ACES) at the University of Illinois.

For the study, DonaldMolinaChaves, a doctoral student, tested four levels of finasteride -- 0, 10, 100, and 1000 milligrams per kilogram of food -- in male mice genetically predisposed to atherosclerosis. The mice consumed the drug, along with a high-fat, high-cholesterol diet, for 12 weeks. After the experiment levels of cholesterol and other lipids in the mice, along with evidence of atherosclerotic plaques were analysed. He also tested gene expression in the liver, looked at bile acid metabolism, and analysed steroids, triglycerides, immune activity, and more.

In mice taking high finasteride doses, the researcher found reductions in total plasma cholesterol, delayed atherosclerosis progression, lower inflammation in the liver, and related benefits. Men taking 1 milligram or 5 milligram doses of finasteride daily for hair loss and enlarged prostate,showed a reduction in total plasma cholesterol and LDL-C levels.

The findings of the study suggest that the accumulation of finasteride in tissues such as the prostate and the hair follicle inhibits the activity of the 5 alpha-reductase 2protein to block the conversion of circulating testosterone to its active metabolite. As a result, finasteride mitigates the harmful action of the active metabolite in these tissues without causing significant side effects.

References: Patrick McQueen, Donald Molina, Ivan Pinos, Samuel Krug, Anna J. Taylor, Michael R. LaFrano, Maureen A. Kane, Jaume Amengual. Finasteride delays atherosclerosis progression in mice and is associated with a reduction in plasma cholesterol in men. Journal of Lipid Research, 2024; 65 (3): 100507 DOI: 10.1016/j.jlr.2024.100507

Ultra-processed foods could potentially become the new 'silent' killer

Ultra-processed foods, termed the new “silent killer”, range from fizzy drinks to cereals and packaged snacks to processed meat, and are packed with additives like oil, fat, sugar, starch, sodium, and emulsifiers such as carrageenan, mono- and diglycerides, carboxymethylcellulose, polysorbate, and soy lecithin, often strip away nutrients and potentially harm human health.

The study conducted by Physicians from Florida Atlantic University's Schmidt College of Medicine and published in The American Journal of Medicine provides important insights about the harmful effects of ultra-processed foods and the myriad of diseases it causes such as diabetes, coronary heart disease, stroke, a variety of cancers, and even mental health disorders.

"When the components of a food are contained within a natural, whole food matrix, they are digested more slowly and more inefficiently, resulting in less calorie extraction, lower glycemic loads in general, and lower rise in triglyceride-rich lipoproteins after eating, which could result in atherosclerotic plaque," said Allison H. Ferris, M.D., senior author, an associate professor and chair, Department of Medicine, and director of the internal medicine residency program, FAU Schmidt College of Medicine. "Therefore, even if few additives are removed from the ultra-processed food, there would still be concern for an over-consumption of these products possibly leading to obesity, diabetes and heart disease."

Public health organizations increasingly utilize the NOVA classification system, categorizing foods into whole foods, culinary ingredients, traditionally processed foods, and ultra-processed foods which are industrially made with non-kitchen ingredients, and pose risks due to undigested additives like emulsifiers. These additives could help harmful gut bacteria, potentially leading to a disrupted microbiome in susceptible individuals.

"Additives, such as maltodextrin, may promote a mucous layer that is friendly to certain species of bacteria that are found in greater abundance in patients with inflammatory bowel disease," said Dawn H. Sherling, M.D., corresponding author, associate program director for the internal medicine residency and an associate professor of medicine, FAU Schmidt College of Medicine. "When the mucous layer is not properly maintained, the epithelial cell layer may become vulnerable to injury, as has been shown in feeding studies using carrageenan in humans and other studies in mice models, using polysorbate-80 and cellulose gum, triggering immunologic responses in the host."

The authors added that there have been marked increases in colorectal cancer in the population, especially among younger adults. They suggest that increased ultra-processed food consumption may be a contributor as well to several other gastrointestinal diseases.

References: Dawn Harris Sherling, Charles H. Hennekens, Allison H. Ferris. Newest updates to health providers on the hazards of ultra-processed foods and proposed solutions. The American Journal of Medicine, 2024; DOI: 10.1016/j.amjmed.2024.02.001