Stuff I learned from @jenngarrison about her work in studying female reproductive biology and the neuroscience of aging:
@jenngarrison We don’t know what signals menopause to happen! We don’t know why it’s so incredibly variable (it can last anywhere from two to ten years, and happen anywhere from your thirties to your fifties.)
@jenngarrison We know some of these features of menopause are heritable, but we don’t have any human biobanked datasets that include records of menopause symptoms or menstrual cycles so we can correlate them with biomarkers.
@jenngarrison Mice don’t have true menopause, which makes it hard to study in the lab; just removing the ovaries causes some menopause-like symptoms but it’s not an exact model. The only species besides humans who go through menopause are some whales and monkeys.
@jenngarrison (And are there biobanks full of whale tissue and whale ovaries at various ages? There are not. It’s probably easier to get hold of a human tissue sample than a whale’s.)
@jenngarrison But mouse researchers aren’t off the hook! Female mice do, at least, have menstrual cycles; and researchers don’t routinely stage them by day in their cycle! We obviously see greater female than male variability in hormones & gene expression — but it’s not correlated to cycle!
@jenngarrison Also it’s not routine for doctors to note date of last period in medical records, so we don’t have anywhere enough data on which medical conditions are cyclical. Did you know most women’s psych admissions are during menopause or the premenstrual phase of the cycle?
@jenngarrison I <3 the Tabula Muris with its single-cell transcriptomics data on old and young mice — but you know what tissue they don’t have? Ovarian.
@jenngarrison Has anyone taken a cervical swab for every day of a mouse’s cycle (it’s only four days long!) and tracked transcriptional or proteomics changes to find out what pathways have periodicity on that scale? The Garrison lab is doing it now — but nobody has before!
@jenngarrison Does anybody even *stage their f’in female mice* in experiments so they can be stratified by menstrual phase? They do not.
@jenngarrison On a slight tangent: we also do not know what signals the onset of birth contractions. (No, it’s not just oxytocin, that’s a peripheral signal to smooth muscle at the very end of the process. The cervix is softening up for weeks before. Which is why induced labor kicks so much!)
@jenngarrison The master switch for female reproductive changes, as for most hormones, is in the hypothalamus. And the cool thing is that we can stick a tiny camera in there, in an awake mouse, and track neuronal activity, and even turn specific clusters on and off with optogenetics.
@jenngarrison You can do all kinds of freaky things by stimulating different parts of the hypothalamus: make a mouse drink, make it lose or gain weight, alter sexual activity, etc.
@jenngarrison And of course a lot of these hypothalamic responses get disrupted with age, and you can delay aging by manipulating the hypothalamus (eg heating it makes mice live longer!)
@jenngarrison so similar methods are probably usable to understand how female reproductive function is regulated and changes with age (albeit not true menopause; you're not going to get to drill holes in healthy women's skulls For Science.)
