I'll take a stab at it, but I'm not a doctor or a biologist.
Cyanide will kill you. Almonds have trace amounts of cyanide. You can eat almonds till you get sick, but that tiny amount of cyanide won't kill you. The dose makes the poison. On the other hand, those fancy car-fentanyl, if a flake touches your skin, you'll od and die. It's super super toxic.
One flake of microplastics in your body isn't going to do anything.
Now,
> although recent studies associated MNP [micro- and nanoplastic] presence in carotid atheromas with increased inflammation and risk of future adverse cardiovascular events
It's not like every muscle fires on every heartbeat. They try, but some are old or dead. There are a lot of them, all working together. And they're constantly repairing or regrowing new muscle cells. How does the heart shed microplastic? Can it? How much till the immune system kicks in and starts causing inflammation? Inflammation is generally good, but super dangerous in the heart. Too much inflammation, and well, it stops firing correctly.
> what is not clearly understood is the internal dose in humans.
How much microplastic is too much? nobody knows. Seems like, you get too much, and repair systems start kicking in. The repair systems can't actually fix anything, but make you weak/sick, and you're generally worse off. When some other thing shocks the system, your body is already in panic mode, so the "normal" response of panicking doesn't change anything. Odds are, you just die.
Cyanide will kill you. Almonds have trace amounts of cyanide. You can eat almonds till you get sick, but that tiny amount of cyanide won't kill you. The dose makes the poison. On the other hand, those fancy car-fentanyl, if a flake touches your skin, you'll od and die. It's super super toxic.
One flake of microplastics in your body isn't going to do anything.
Now,
> although recent studies associated MNP [micro- and nanoplastic] presence in carotid atheromas with increased inflammation and risk of future adverse cardiovascular events
It's not like every muscle fires on every heartbeat. They try, but some are old or dead. There are a lot of them, all working together. And they're constantly repairing or regrowing new muscle cells. How does the heart shed microplastic? Can it? How much till the immune system kicks in and starts causing inflammation? Inflammation is generally good, but super dangerous in the heart. Too much inflammation, and well, it stops firing correctly.
> what is not clearly understood is the internal dose in humans.
How much microplastic is too much? nobody knows. Seems like, you get too much, and repair systems start kicking in. The repair systems can't actually fix anything, but make you weak/sick, and you're generally worse off. When some other thing shocks the system, your body is already in panic mode, so the "normal" response of panicking doesn't change anything. Odds are, you just die.