“Repeated Infections Linked to Increased Risk of Dementia, Study Finds”

[메디컬투데이=이승재 기자] Research has shown that repeated infections increase the risk of dementia.

Cognitive decline is normally observed during the aging process. Similarly, pathological aging processes are associated with cognitive impairments such as Alzheimer’s disease.

According to previous studies, inflammation caused by bacterial infection accelerates brain aging, which can lead to cognitive impairment. In particular, studies have shown that LPS, a toxin present in the outer membrane of bacteria, plays a key role in reducing cognitive function caused by inflammation.

However, since these studies investigated cognitive functions in laboratory animals exposed to LPS for a short period of time, it is difficult to know the changes in cognitive abilities that occur when repeatedly exposed to LPS for a long period of time.

The research team administered progressively higher doses of LPS to mice five times over 75 days and observed changes in their cognitive abilities. As a result of the study, mice given LPS showed difficulty in learning and maintaining memory.

As a result of a brain biopsy, mice that received LPS showed changes in the hippocampus, an area in the brain responsible for memory and learning. The hippocampus is the area where the earliest degenerative changes appear in Alzheimer’s disease.

As a result of further research, when LPS was administered, the expression level of interleukin-6, an inflammatory substance, increased in the hippocampus and the extent of organ enhancement decreased. Long-term potentiation (LTP) refers to the fact that one neuron is activated more frequently than another and synapses between neurons are strengthened, which is the basis for memory and learning. This decrease in the extent of organ enhancement indicates that cognitive impairment is caused by inflammation.

The researchers concluded that repeated infection reduces cognitive abilities, which increases the risk of dementia.

Reporter Lee Seung-jae of Medical Today (ecctomas@mdtoday.co.kr)

[저작권자ⓒ 메디컬투데이. 무단전재-재배포 금지]