Nordic Life Science 1
“Stem cells remain in the body throughout life. T
herefore, they have more time to accumulate genetic mutations and epigenetic changes, factors that can alter tissue function and lead to aging or the development of cancer.” D 60 | NORDICLIFESCIENCE.ORG R. AZNAR BENITAH, GROUP LEADER AT the Insitute for Biomedical Research in Barcelona, Spain (IRB Barcelona), emphasizes the importance of studying stem cells to understand how healthy tissues are maintained, why they deteriorate with age, and how serious diseases such as tumors appear. Stem cells are responsible for constantly replacing the hundreds of millions of cells we lose every day, and for repairing and maintaining healthy tissues, he says. “Some tissues renew themselves very quickly. Skin does so approximately every 14 days, and the intestine or colon in several weeks. The cells that make up these tissues have a short lifespan and eventually disappear. In contrast, stem cells remain in the body throughout life. Therefore, they have more time to accumulate genetic mutations and epigenetic changes, factors that can alter tissue function and lead to aging or the development of cancer,” he explains. When cells age Aging is a progressive decline in cellular function. On the one hand, some cellular organelles, such as mitochondria, accumulate damage within cells due to wear and tear and oxidation. On the other hand, each time DNA replicates, since it is not a perfect mechanism, it makes errors that accumulate over the years as mutations, affecting cellular function. The autophagy mechanism (when the cell eliminates damaged components within itself ) also loses efficiency and leads to an accumulation of damaged components. Another factor that is altered with aging is the circadian rhythm, the biological clock that coordinates when to rest, eat, repair tissues, or be active. When this clock malfunctions, wear and tear increases and more errors occur. “Today we are exposed to what is called ‘social jet lag’; the blue light from mobile phones, tablets, and screens is precisely the wavelength that the brain interprets as sunlight. So, when it’s 10 p.m. and the body should be preparing for sleep, the screen is sending it the signal that it’s still daytime. This disrupts the internal clock and, if maintained over time, can lead to metabolic disorders, poorer sleep, inflammation, and faster cellular aging,” says Aznar Benitah. “There comes a point when a cell can stop functioning properly or enter a state of senescence. It is still alive, but it no longer performs its function well. It is an aged cell, present, but increasingly less useful to the organism,” he adds. W hen mutations affect key genes, such as those that regulate damage detection or the elimination of defective cells, it promotes the development of tumors. One example is the p53 gene, known as the “guardian of the genome”. When it functions correctly, it detects cell damage and can halt cell division or induce cell death. But if this system fails or mutates, damaged cells can continue to survive and proliferate. In addition to this, cell function is affected EUROPE // SCIENCE