Medical Bulletin 06/December/2023

Here are the top medical news of the day:

Exercise training improves obesity-related dementia

Obesity is a major risk factor for cardiovascular metabolic diseases and neurodegenerative diseases such as dementia. Long-term exercise improves memory and spatial cognition, reduces age-related cognitive decline, and maintains brain volume, but the mechanisms are not fully understood.

Recently, a study from Febbraio lab at Monash University reported that voluntary exercise training (VET) improves long-term memory in high-fat diet (HFD)-induced obese mice, increases hippocampal neurogenesis and the expression of the neurotrophic factor BDNF in the hippocampus, and decreases the expression of the inflammatory factor TNF, suggesting that long-term physical activity can prevent obesity-induced cognitive decline.

Particularly, these results showed that VET upregulated Bdnf mRNA levels in the hippocampus of obese mice, but had no significant effect on BDNF protein levels in the hippocampus and blood, consistent with previous reports that the increase in BDNF expression in the hippocampus is transient and occurs only within a limited time window. The downregulation of TNF expression after exercise training suggests that exercise may induce a mild inflammatory stimulus in the brain, contributing to mouse memory improvement.

In summary, this study reveals the crucial role of exercise training in prevention of obesity-induced cognitive dysfunction and neurodegenerative diseases.

Reference: Exercise training improves obesity-related dementia; Life Metabolism; DOI: 10.1093/lifemeta/load043/7422812

Eating beans improves gut health, regulates immune and inflammatory processes in colorectal cancer survivors

Incorporating navy beans into the diet of colorectal cancer (CRC) survivors has the potential to positively impact both gut and host health by modulating markers linked to obesity and disease, according to new research from The University of Texas MD Anderson Cancer Center.

The findings published today in eBIOMedicine, part of The Lancet family of journals, revealed BE GONE trial participants who added a cup of navy beans daily to their regular meals saw positive changes in their gut microbiome, which is associated with cancer prevention and improved treatment outcomes. Changes included an increase of alpha diversity, or beneficial bacteria (Faecalibacterium, Eubacterium and Bifidobacterium) and a decrease in pathogenic, or opportunistic, bacteria.

The randomized BE GONE trial followed 48 men and women over age 30 who met the criteria for obesity via body mass index (BMI) or waist size and who had a history of bowel lesions. This included patients with a history of CRC (75%) and/or high-risk, precancerous polyps of the colon or rectum detected at colonoscopy. For eight weeks, participants either followed their regular diet or included a daily cup of organic, canned pressure-cooked white navy beans.

The study highlights the therapeutic role of naturally prebiotic-rich foods, while further emphasizing the need for consistent and sustainable dietary adjustments for high-risk cancer patients. In the next steps, researchers will focus on a wider variety of prebiotic foods and how changes to the microbiome affect patients undergoing immunotherapy.

Reference: Eating beans improves gt health, regulates immune and inflammatory processes in colorectal cancer survivors; UNIVERSITY OF TEXAS M. D. ANDERSON CANCER CENTER

New study links blood glycerol levels to tuberculosis severity in Type 2 Diabetes

A collaborative study between the A*STAR Infectious Diseases Labs (A*STAR ID Labs) and the University of Massachusetts (UMass) Chan Medical School has uncovered that elevated glycerol levels are responsible for increased severity of tuberculosis (TB) disease in experimental models with Type 2 diabetes (T2D).

This research advances our understanding of how both diseases interact with each other, identifying elevated glycerol and an enzyme utilising glycerol in the pathogen responsible for causing TB as novel therapeutic avenues for treating patients with these conditions. The paper was published in Nature Communications on 20 September 2023.

This study sheds light on the mechanism behind this interaction and the exacerbated TB disease among the experimental models with T2D. It also underscores the vital importance of preventative and proactive disease management in T2D patients, aligning with the Healthier SG plan’s key priorities.

The researchers of this study found that T2D led to more bacteria in the lung, tissue damage and deaths when infected with Mycobacterium tuberculosis (Mtb), the bacterial pathogen responsible for causing TB. Notably, elevated blood glycerol, a sugar alcohol, emerged as a crucial factor influencing the interaction between T2D and TB. When the ability of Mtb to utilise glycerol for metabolism was blocked, by deleting an enzyme known as glycerol kinase, the severity of lung damage decreased. This indicated that Mtb can feed on glycerol to drive TB disease severity in T2D. As a result, people with T2D are more likely to be susceptible to TB because Mtb can utilise excess glycerol present in their blood and bodies, leading to more severe disease.

This study makes a significant breakthrough in our understanding of TB-T2D interactions by pinpointing elevated glycerol as a novel therapeutic target for treating TB disease in T2D patients. This paves the way for developing innovative host-directed therapeutics, which is crucial for addressing the heightened susceptibility of T2D populations to TB.

Reference: New study links blood glycerol levels to tuberculosis severity in Type 2 Diabetes; Nature Communications