Tag: aging

A New Look at Biology, Aging and (Im)mortality

Immortality for Humans? Perhaps

I remember a patient I saw as an intern. She was 95 years old, and had come in with a kidney stone. When I pulled her medical chart, I was taken aback. It was only 5 pages long. She had never been admitted to the hospital, unlike the typical 65 year olds who had hundreds of pages of records.

A sage attending physician told me that was very common, that 90 year olds often had never been admitted to a hospital. “That’s how they get to be 95,” he said. At the time, I thought it was very odd that the 95 year old looked much healthier than most 65 year olds.

A recent paper in Science, reviewed in NY Times by Zimmer, may shed some light on this. It found that your risk of dying starts decreasing after age 80 and raises the possibility that there may be no limit to human lifespan. More importantly, it lends support to the hypothesis that aging is genetically programmed, and that it’s under evolutionary selection.

Continue reading “Immortality for Humans? Perhaps” →

A New Look at Biology, Aging and (Im)mortality

Are We Programmed to Get Cancer?

When my son was in kindergarten, he somehow talked us into getting him two rats as pets. It’s not as bad as it sounds. Rats, apart from their unattractive tail, make great pets. Very friendly, intelligent, and clean. Although I did take offense to the fact that they insisted on cleaning themselves for five minutes each time after being touched by humans…

They eventually got old (2 to 3 years old), and succumbed to cancer, as they often do.

They got old… and got cancer…

That doesn’t sound odd unless you step back and ask, why did they get cancer when they were only 2 or 3 years old? And why do “old” dogs get cancer when they get to be 7 or 8 years old? We humans don’t get cancer, for the most part, until we are in our 50s, 60s, or older. Why is it that we don’t usually get cancer when we are 2 or 3 or 8 years old, but animals with shorter lifespans do?

This exposes a critical flaw in the current thinking about etiology of cancer. The current thinking is that after a certain number of cell divisions, and after a certain length of time, our cells accumulate too many mutations and then we get cancer.

That theory is demonstrably, and patently wrong. If that theory were correct, rats would never get cancer. But they get cancer quite often when they’re more than couple of years old.

And if that theory were correct, then large animals should get cancer a lot more frequently than small ones, because the cells have to divide so many more times in order to create a larger animal. This paradox is called Peto’s paradox. There are some efforts to rationalize away this paradox, such as arguments that large animals have increased number of tumor suppressor genes, but that just begs the question: why don’t small animals evolve more tumor suppressor genes themselves to live longer, or why don’t all animals evolved enough tumor suppressor genes to never get cancer?

More fatal to the theory is the fact that some animals don’t get cancer, or almost never get cancer. Naked mole rats for example. Horses and other related species for another (except non-metastatic melanomas). Maybe even lobsters.

So what’s the alternative explanation? The most logical explanation is that cancer arises when animals get biologically old. Species that don’t age or age very slowly, like the naked mole rats and lobsters, seem to have very low rates of cancer. In other words, cancer is programmed into our biological clock. When we’re biologically young, we suppress tumors. When we get older, the brakes come off. This is in line with my previous post about how aging is probably programmed. It is also in line with recently findings that we have cancer causing mutations all over our skin (and probably throughout the body), that don’t cause cancer until something else allows cancer to emerge. It’s becoming clear that cancer is not really caused solely by mutations–there are other required factors that must exist before the tumorigenic mutations can cause cancer.

If true, then this theory has important implications. It means that we should be able to prevent cancer very effectively, if we can decipher what is the molecular clock that governs aging.

A New Look at Biology, Aging and (Im)mortality, Drug Development, New Discoveries

Will We Cure Diabetes, Heart Disease, and Alzheimer’s Disease One Day?

FDA, in 2008, did something that many people thought was preposterous. They began requiring companies to prove that diabetes drugs they developed did not kill people. Actually, to be more specific, they required the companies to prove that the risk of dying on the drug was not more than 1.8X higher than not being on the drug.

This caused an uproar. To prove such a ridiculous thing, some companies howled, would Continue reading “Will We Cure Diabetes, Heart Disease, and Alzheimer’s Disease One Day?” →

A New Look at Biology, Aging and (Im)mortality, Germs

Why Do We Age? Because of Parasites. Or, the Red King Theory

So there’s this paper I’ve been trying to get published for a little while. It lays out my hypothesis for why we age. You can see the preprint here on the bioRxiv server. The journal editors really don’t seem to like it, probably because it is completely against the grain of current thinking, although a handful of people who have seen it on bioRxiv seem to like it quite a bit.

In the past, I had never been that interested in aging, because I get depressed when I think about degenerative diseases. I think it comes from when I was training as a doctor and I would see patient after patient with hypertension, diabetes, and heart disease. The older doctors taught me that our job was not to cure these patients–that was impossible–but to slow down the inevitable progression of these diseases. I didn’t like that. I like to fix people, I like to fix problems, I like to fix companies.

But my interest was piqued when I read a review article in Science couple of years ago that declared that it was just a matter of time before we could reverse aging. Continue reading “Why Do We Age? Because of Parasites. Or, the Red King Theory” →