Transplanting brain cells may aid in treating various neurological disorders and brain injuries.

We know that many neurological disorders are caused by the loss of cells in the central nervous system or lead to such loss. Some diseases result from the loss of specific cells, for instance, in amyotrophic lateral sclerosis (ALS), there is a loss of motor neurons, in Parkinson's disease, there is a loss of dopaminergic neurons, and in Huntington's disease, there is a loss of GABAergic neurons.

Although many brain diseases are characterized by the loss of specific cells, a common link among all these diseases is the loss of astrocytes.

The data available today suggest that astrocytes play a role in essential brain functions, including homeostasis and modulation of neural networks necessary for everyday cognitive processes. Healthy astrocytes are vital for brain function, which is why finding strategies to heal or replace damaged astrocytes could aid in treating many neurological disorders.

Cellular replacement therapy involves transplanting functional cells to patients. In recent years, there have been intriguing developments in the field of astrocyte transplantation in animal models of diseases, with one approach even progressing to early clinical trials for ALS patients. Despite promising results, the success of treatments varies across different studies.

A recent study published in The Journal of Neuroscience examined how transplanted astrocytes integrate into the recipient's central nervous system. The study looked at the types of transplanted astrocytes, treatment timelines, and transplantation methods.

Initially, researchers prepared astrocyte cultures in Petri dishes by extracting immature astrocytes from the cortex of newborn mice and expanding the cell population before transplanting them into the brains of other mice.

The findings revealed that transplanted astrocytes can develop normally, integrate into the recipient's brain, and function similarly to the host's own astrocytes (with minor differences).

The ability of astrocytes to perceive signals and exchange information in the brain occurs through molecules such as receptors and ion channels located on their cell surface. Transplanted astrocytes exhibit a comparable number of these receptors and channels and possess similar sizes and complexities when compared to the recipient's own astrocytes.

Transplanted astrocytes require some time to catch up and fully match the recipient mice's astrocytes in terms of producing these receptors and ion channels.

Interestingly, the integration of transplanted astrocytes into the recipient's body depends on the age of the mouse, reflecting the maturity of the cellular environment into which the astrocytes are transplanted. When astrocytes were transplanted into infant mice, they could migrate and spread in the host's brain more intensively. However, when astrocytes were transplanted into young adult mice, they were limited to the transplantation site.

Astrocytes in different regions of the brain and spinal cord exhibit entirely different characteristics. Researchers were curious to see how astrocytes from one brain region integrate into another. Astrocytes obtained from the cerebral cortex transformed into cortical astrocytes even when placed in the cerebellum.

Thus, the sources and types of transplanted astrocytes matter, and this intrinsic programming of astrocytes should be considered when discussing astrocyte replacement therapy.

In recent years, there has been an increasing number of studies exploring the possibilities of astrocyte transplantation. These studies have shown that astrocyte transplantation also promotes brain plasticity and regeneration following injuries and neurological disorders. Therefore, it represents a promising and exciting strategy for treating neurological diseases.