It is estimated that more than 150 million people could be living with Alzheimer’s disease in 2050; each risk factor must be better understood and taken into account.
The research, which followed its participants even before they were born and until the age of 50, suggests a new clue to the origins of Alzheimer’s disease: stress-related immune activity during the late 2nd or The beginning of the 3rd trimester of pregnancy could indeed have very long-term effects on the circuits, functions and decline of the child’s memory, and thus increase the risk of Alzheimer’s later in life.
The research leads to different conclusions depending on the sex of the childand neuroscientists point out that differences in immune function between the sexes begin in fetal development. While it is widely recognized that the brain circuits underlying memory differ by biological sex, sex-related drivers of aging and Alzheimer’s disease are poorly understood.
Brain aging is also linked to brain development
The study analyzes data from 18,000 participants followed before birth and for more than 50 years and highlights the impact of maternal immune activity during a critical period on the baby’s brain development. The analysis is focused on 204 individuals born during follow-up, exposed or not to an unfavorable in utero immune environment,
that is, at high levels of immune markers, such as the cytokines IL-6 and TNF-a,
which were followed until middle age, 50 years later. The team used functional brain imaging to examine the impact of this early exposure on brain regions of memory circuits that are rich in these cytokine receptors and sex hormone receptors and that show differences in development and of functioning according to sex from fetal development.
- high levels of IL-6 and TNF-a in mothers during pregnancy are linked to differences in brain activity;
- these differences are unfavorable differently depending on the sex, particularly in memory circuits later in life: this negative effect is more significant in women, after menopause;
- these postmenopausal women, formerly exposed to maternal inflammation in utero, express these same pro-inflammatory markers in their fifties;
- the impact of these immune markers also occurs in childhood, and is manifested by a reduction in the cognitive performance of children at the age of 7;
- This elevated prenatal maternal immune activity also appears to contribute to the development of increased stress and immune system sensitivity in offspring, further predisposing factors to memory disorders, such as Alzheimer’s disease, later in life. in life;
- the effect of in utero exposure to maternal inflammation is sex dependent;
- maternal inflammation thus impacts the circuits and functioning of the long-term memory of the offspring during childhood and in middle age,
- with different patterns for men and women.
One of the lead authors, Dr. Jill M. Goldstein, professor of psychiatry and medicine at Harvard Medical School concludes: “Brain aging is also linked to brain development, and understanding sex differences in brain development is essential to understanding sex differences in the aging brain. This is why it is essential to understand the fetal origins of Alzheimer’s diseasewhich, like many chronic diseases, develops throughout life and is influenced by early development.”
Research continues and continues to follow participants as they agewith monitoring of amyloid levels and other measures of Alzheimer’s disease markers. Better understanding how maternal immune activity influences the development of the fetal brain and then its aging will perhaps make it possible to intervene earlier and somewhat reduce the incidence of Alzheimer’s disease. For the next generations.
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