In a new study published in the journal Science Advances, people with dementia have protein buildup in their astrocytes, which may cause abnormal antiviral activity and memory loss. Dysfunction in neurons, which convey information throughout the brain, has long been suspected as the cause of dementia-related cognitive problems.

Researchers from Weill Cornell Medicine revealed that abnormal immune activity in non-neuronal brain cells called astrocytes is sufficient to cause cognitive deficits in dementia. While neurons have been extensively examined in dementia and other illnesses, considerably less study has been conducted on astrocytes, which many scientists believe play primarily supporting functions in brain health. 

In the study, the researchers examined tissue samples from deceased individuals who were diagnosed with either Alzheimer`s disease or frontotemporal dementia. They found that the brain tissues had an accumulation of a protein called TDP-43 in astrocytes within the hippocampus. The researchers also stated that the buildup of TDP-43 in astrocytes in the animal model was sufficient to cause progressive memory loss but no other behavioral changes.

The lead author of the study also explained that astrocytes produce excessive amounts of immune messengers called chemokines, which can activate CXCR3 chemokine receptors. He noted that these chemokines can infiltrate immune cells. 

However, the team also observed that CXCR3 receptor levels were elevated in hippocampal neurons and that excessive CXCR3 receptor activity made neurons "hyperactive". Hence, they concluded that blocking CXCR3 reduced neuronal firing in individual neurons and alleviated cognitive deficits caused by astrocytic TDP-43 buildup. 

(Source: https://theprint.in/health/astrocyte-dysfunction-causes-cognitive-decline-study/1533249/ )