Study finds how ageing reduces ability of regulatory T cells to enhance myelin regeneration
Alicante, Spain: Regulatory T lymphocytes are immune system regulators that also perform a variety of reparative roles, such as the regeneration of myelin.
In an effort to ascertain whether the function of these cells is compromised with ageing, Alerie Guzman de la Fuente, a Miguel Servet investigator at the Institute for Health and Biomedical Research of Alicante (ISABIAL) and the Institute for Neurosciences (IN), a joint centre of the Miguel Hernandez University (UMH) of Elche and the Spanish National Research Council (CSIC), co-led a study in which she was assisted by researcher Denise Fitzgerald from Queen's University Belfast (UK).
The study revealed that while the number of regulatory T lymphocytes increases with age, so does their capacity to stimulate the production of oligodendrocyte progenitor stem cells (OPCs) to replace lost myelin.
Myelin is a protective layer present in the nervous system that surrounds nerve fibers, allowing quick and appropriate communication between neurons: "It is similar to the plastic that covers the copper in a cable," explains Guzman de la Fuente, and she points out that myelin loss linked to ageing or neurodegenerative diseases, such as multiple sclerosis, has serious consequences for neurological functions. In this work, published in the journal Nature Communications, the researchers have focused their study on how ageing, a key risk factor that limits myelin regeneration, affects the regulatory T cells regenerative functions in the brain and spinal cord.
To carry out this study, the researchers used mice that are between 19 and 23 months old as an animal model, which resembles an approximate age of 65 to 70 years in humans. The experts detected that the presence of regulatory T lymphocytes increases with age, however, these had lost the ability to enhance the conversion of OPCs to new oligodendrocytes that regenerate myelin upon damage.
The researchers wanted to figure out whether this loss in regulatory T cell function was completely irreversible. To do so, they carried out several experiments in young mice in which they replaced their young regulatory T lymphocytes by aged ones and verified that, in a young animal both, young and aged cells, have the same capacity to enhance myelin regeneration.
The results of these experiments, in which researchers from the Institute for Neurosciences and from ISABIAL Francisco Javier Rodriguez Baena and Sonia Cabeza Fernandez have also participated, together with a team of researchers from the University of Cambridge (UK), Altos Laboratories (UK) and the University of Syddansk (Denmark), are very positive because they suggest that the loss of function may be reversible.
"Regulatory T lymphocytes are very complex because they modulate the immune system and in patients, it is not feasible to eliminate and exchange them for young cells", says Alerie Guzman de la Fuente and she explains that this led the team to study in depth what was different between young and aged regulatory T cells. The objective was to identify some of the mechanisms involved in the failure to enhance myelin repair associated with regulatory T cell ageing to modulate them in a more specific manner", clarifies the researcher.
