Does infection of the blood impact and accelerate dementia in later life?
Tatiana Barichello, Ph.D.
University of Texas Health Science Center, Houston
Houston, TX - United States
Sepsis (infection of the blood) occurs when the bloodstream is overwhelmed by tiny invaders (such as bacteria, viruses, parasites etc.) and as a result of the body attempting to fight the infection, the bodies’ organs can begin to shut down; it can be deadly. In the United States, each year about 1.5 million people develop sepsis and it leads to at least 250,000 deaths. Past studies indicate that individuals with sepsis have a 3-fold risk for developing cognitive impairment later in life.
Dr. Tatiana Barichello believes that the immune system, which protects against diseases caused by these tiny invaders, is associated with potentially harmful substances that reach the brain and accelerate or lead to cognitive decline and potentially Alzheimer’s dementia. Individuals with Alzheimer’s, typically experience brain inflammation caused by an uncharacteristically active immune system. It becomes critical then to evaluate if sepsis accelerates or leads to Alzheimer’s dementia.
To conduct their study, Dr. Barichello and colleagues will use genetically engineered Alzheimer’s-like mice. The researchers will subject the mice to sepsis-like conditions and then determine if it accelerates brain changes seen in Alzheimer’s in these mice after recovery. Secondly, Dr. Barichello will evaluate biological markers of Alzheimer’s using blood samples from four groups: 1) individuals who are cognitively unimpaired, 2) individuals with sepsis, 3) individuals who have recovered from sepsis and 4) people with Alzheimer’s. Furthermore, the researchers will also compare the levels of beta-amyloid plaques— a hallmark of Alzheimer’s —and inflammatory proteins in the blood of individuals with Alzheimer’s and the rest of the other groups. Dr. Barichello proposes that inflammation triggered by sepsis will increase the levels of beta-amyloid plaques in the blood of individuals who have survived sepsis.
If successful, the study results could pave the way to delay or prevent the onset of dementia in individuals with sepsis by paying closer attention to the immune system and by blocking the poison in the blood from reaching the brain. It may also shed light on possible risk factors for later life Alzheimer’s or related dementias.
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