Medical Bulletin 15/ April/ 2024

 Here are the top medical news for the day:

Can tissue ageing be decreased through exercise?

In a study published in the journal Nature Ageing, scientistsfrom Amsterdam UMC, in collaboration with Maastricht UMC have discovered that a type of fat accumulates as tissue ages and that this accumulation can be reversed through exercise.

Lipids are an important part of our diet, and crucial for the functioning of our body cells. Specific lipids make up the membrane of cells, which ensures that the inside and outside remain separate. These lipids can serve as biomarkers of tissue ageing due to their roles in various physiological processes. For instance, certain lipids, such as ceramides and sphingolipids, accumulate in tissues over time and are associated with cellular senescence and age-related diseases. They also play important roles in cell signalling pathways related to inflammation, apoptosis, and oxidative stress, which are key contributors to tissue ageing.

In the study, the research team investigated how the composition of fats changes in mice. They looked at ten different tissues, including muscles, kidneys, liver and heart and noticed that one type of lipid, the bis(monoacylglycerol)phosphates (or BMPs), were elevated in all tissues from the older animals suggesting an accumulation of these lipids during ageing. They then investigated whether this also happens in humans. Although it was not possible to obtain as many different tissues, the accumulation of BMP was also visible in muscle biopsies of older people. Finally, they completed more muscle biopsies from people before and after a healthy intervention that included one hour of exercise a day and saw the level of BMPs decreased in the active participants.

"The idea that we could reverse aging is something that was long considered impossible, but these findings do allow us to understand a lot more about the aging process,” says Riekelt Houtkooper, Professor at the laboratory Genetic Metabolic Diseases of Amsterdam UMC.

"Everyone says that 'it's just part of getting older,' but this doesn't actually have to be true. By understanding more about the aging process, we can also look into new ways of intervening," says Georges Janssens, first author of the paper and assistant professor at Amsterdam UMC.

Reference:Janssens, G.E., Molenaars, M., Herzog, K. et al. A conserved complex lipid signature marks human muscle aging and responds to short-term exercise. Nat Aging (2024). https://doi.org/10.1038/s43587-024-00595-2

Consuming sugary drinks in childhood linked to adult obesity, finds study

According to a new study by the School of Psychology at Swansea University, consuming sugar-sweetened drinks in the first few years of childhood can be linked to poor diet patterns that increase the risk of obesity in later life.

The findings are published in the journal European Journal of Clinical Nutrition.

Previous reports have stated that consuming sugar-sweetened drinks in childhood is associated with a greater risk of obesity, and some studies have treated all sweet drinks as similar; for example combining carbonated drinks, sweetened tea, energy drinks, fruit-based drinks, and 100% fruit juice with no added sugar has been linked to increased body weight.

In the study, researchers tracked the influence of diet on 14,000 children from birth to adulthood using the Avon Longitudinal Study of Parents and Children.

The key findings of the study revealed that:

1.Children who drank fizzy drinks such as cola or sugar-sweetened fruit cordials before the age of two gained more weight when they were 24 years old. Girls who had pure fruit juice gained less weight, while the weight of boys remained the same.

1.At three years of age, toddlers who drank cola consumed more calories, fat, protein, and sugar but less fibre. In contrast, those given pure apple juice consumed less fat and sugar but higher amounts of fibre.

The finding of this study highlighted that the sweet drink given to children before two years of age was associated with adiposity at 24 years of age. In males, early exposure to cola, fruit squash, or fizzy drinks was at three years associated with a diet containing more energy, carbohydrates, fat, protein, and sugar. In contrast, early exposure to apple juice was not associated with energy intake at age three years, but there was a higher consumption of protein, and a lower consumption of fat andsugars.The pattern in females was similar.

Reference:Benton, D., Young, H.A. Early exposure to sugar sweetened beverages or fruit juice differentially influences adult adiposity. Eur J Clin Nutr (2024). https://doi.org/10.1038/s41430-024-01430-y

Study suggests lung fibrosis reversal using body's natural healing process

A recent study from a team led by Sean Fortier, M.D. and Marc Peters-Golden, M.D. of the Division of Pulmonary and Critical Care Medicine at the Universityof Michigan Medical School uncovered a pathway used during normal wound healing that has the potential to reverse idiopathic pulmonary fibrosis (IPF).

The most common type of lung fibrosis — scarring of the lungs -- is idiopathic, meaning of unknown cause.It is a chronic and progressive lung disease characterized by the gradual scarring and stiffening of lung tissue.The process by which lung injury either leads to healing or fibrosis relies in part on what happens to a cell called a fibroblast, which forms connective tissue.

During injury or illness, fibroblasts are activated, becoming myofibroblasts that form scar tissue by secreting collagen. When the job is done, these fibroblasts must be deactivated, or de-differentiated, to go back to their quiet state or undergo programmed cell death and be cleared.

In the study, using a mouse model, researchers simulated IPF by administering bleomycin, a chemotherapy agent that causes cell injury and confirmed that the resulting lung scarring resolved itself over the span of about six weeks.By genetically eliminating MKP1 in fibroblasts of mice after establishing lung injury, the team saw that fibrosis continued uncontrolled. They also performed several additional studies using CRISPR techniques.

“This is the major distinction between normal wound healing and fibrosis – the persistence of activated myofibroblasts. That deactivation is controlled by molecular brakes. The study examined one of these brakes, called MKP1 – which the team found was expressed at lower levels in fibroblasts from patients with IPF. We argued by contradiction: when you knock out this brake, fibrosis that would otherwise naturally disappear, persists and therefore MKP1 is necessary for spontaneous resolution of fibrosis.That’s totally in keeping with the fact that they do slow the progression, but they don’t halt or reverse disease,” said Fortier.

Reference: “MAP kinase phosphatase-1 inhibition of p38α within lung myofibroblasts is essential for spontaneous fibrosis re solution,” Journal of Clinical Investigation. DOI: 10.1172/JCI172826