This is definately pretty cool, the news about the guy who found a sample in an old graveyard was really cool. Going for human remains is definately more likely to contain compounds for breaking us down, although looking in animal is good too because ideally we want to extend the lives of animals as well as humans, both as pets and mine canaries
It's too bad this practise, much like stem cell treatment, would probably have a lot of objectors and seem creepy.
I may be wrong, but is one of the reasons humans have high atherosclerosis our long lifespan that gives it longer to accumulate? Could it also be our consumption of cholesterols/fats in high quantity on a consistent basis with not enough antioxidants able to keep them stable, compared to animals who eat meat raw so it has more vitamins to keep it stable? Still probably better off avoiding all that bacteria but it could explain why we die of arterial disease at an older age compared to animals dying of infections and sicknesses at earlier ages.
Since our lifespan has grown so much recently, really old corpses probably won't have the level of arterial plaque our elderly do nowadays. Differences in diet may have made it less common too, are there stats on it? The corpses that exist with arterial plaque adequate to host such bacteria may not have been around long enough to develope such bacteria yet?
One idea I had sorta... why don't we breed mammals (mice probably) who will have high levels of this plaque, trying to accumulate the highest level of possible (you'd need to prolong death) and then dump their remains into a very warm place (as opposed to the cold earth as normal) to be the ideal environment for the remains to be processed quickly so we can get samples.
Or possibly... can live people contrbute? Sometimes people have surgery to remove clots, why not give the option of donating these clots to science so we can monitor what would break them down. Nothing better for getting a focused sample than mainly clots.