Not many people know this, but our health and our wellbeing also depend on very thin filaments (much thinner than hair) that literally float along our respiratory system and along the other “ducts” in our bodies: these are the cilia found on the surface of particular types of cells, which move rhythmically and, for example, push out the mucus in which bacteria are trapped, or – in the case of the ependymal cells of the brain – mark the boundaries of the cavities of the central nervous system, facilitating the circulation of cerebrospinal fluid (which “envelops” the brain and spinal cord). Ciliated cells also help to push sperm into the vas deferens (a part of the micro-channels that channel sperm into the prostate and the urethra).
Until now, it was not entirely clear how these thin filaments worked, but now a study by the University of Southern California has accurately identified the complex mechanisms that play a part in enabling cilia to work effectively and productively. The results were published in the journal Physical Letters Review.
The watchword for the proper functioning of this system is synchronization, write the researchers, who work in the Department of Aerospace and Mechanical Engineering at the University of California.
The researchers observed that cilia coordinate with each other to achieve specific modes of motion and to optimize the flow of fluids, almost as if they had “decided” to all row in the same direction. But they are also able to shift their level of activity and synchronization.
Cilia – add the researchers – are made up of a series of microtubules, with a series of molecular motors (to use the technical term), i.e. macromolecules capable of converting chemical energy into mechanical force and movement.
Ciliary activity depends on certain substances found in the cilia’s environment, starting with calcium. However, other changes, such as those caused by certain lung diseases, can also modify these activities.
To obtain a precise “picture” of the movements of ciliated cells and their strategies, the bioengineers used an innovative technique, through computational biology models (algorithms and artificial intelligence systems).
“The long-term vision”, explained Eva Kanso, main author of the study, “is that maybe there will be a way to take a swab of ciliated cells, make them grow and use them as a diagnostic tool (based on their coordination) to better understand how far a disease has progressed and what a patient’s prognosis is”.
However, it comes as no surprise that things get very complicated for people who smoke. Several substances contained in cigarettes, in fact, slow down or completely paralyze the ability of cilia to move and expel mucus, which as a result tends to accumulate in the respiratory tract, resulting in a typical smoker’s cough. In the most serious cases (people who smoke a lot, and for a long period of time) the cilia are altered, even to the point of destruction.