Why can the skin of two people of the same age look completely different? And why do some areas of the face age faster than others, even on the same person? Scientists are increasingly concluding that it's not just about the sun, genetics, or lifestyle. It's possible that skin cells are constantly exchanging information about their age – and they do it using tiny biological “packages.”
These are extracellular vesicles, or exosomes. They are microscopic bubbles that cells continuously release into their surroundings. Inside them are proteins, RNA molecules, lipids, and other signals capable of influencing the function of neighboring cells.
At the same time, scientists are increasingly using epigenetic clocks – one of the most accurate ways to determine the biological age of tissue. They assess changes in DNA methylation and show how much a cell has “aged” in terms of its molecular program, rather than by a person’s date of birth.
The authors of a new study suggest that these two phenomena are closely related.
According to their hypothesis, exosomes can carry not just molecules, but information about biological age. Upon receiving such a signal, neighboring cells can alter the activity of their genes related to tissue repair, collagen and elastin synthesis, and protection against inflammation. It turns out that cells can “talk” to each other and transmit signals of aging or, conversely, regeneration.
This can be particularly evident in the skin. After exposure to ultraviolet radiation, chronic inflammation, or severe stress, the composition of exosomes changes. Fibroblasts begin to release different signaling molecules that can accelerate the epigenetic aging of surrounding cells. This helps explain why the consequences of sunburn or prolonged stress eventually become noticeable not only in the damaged area but also in neighboring tissues.
This perspective changes the conventional view of aging. If previously the main focus was on the accumulation of mutations, oxidative stress, and a decrease in the ability of cells to divide, now intercellular communication is coming to the forefront. Aging may be not only an internal process of each cell but also a result of constant information exchange between them.
It is important to understand that this is not about a new method of rejuvenation yet. This is a conceptual work that combines existing data and proposes a new model of what is happening. Scientists still need to experimentally prove whether exosomes can indeed directly alter the course of epigenetic clocks.
If this hypothesis is confirmed, methods may emerge in the future that will not simply combat the effects of aging, but will alter the signals themselves that cells exchange. Perhaps one day medicine will learn to slow down the biological aging of tissues by correcting this molecular dialogue.
Sometimes the most important discoveries are made not when we find a new molecule, but when we understand how cells talk to each other. Perhaps this invisible language will become one of the keys to maintaining youthful skin.
