Forthcoming Book: Replacing Aging
Replacing Aging is a forthcoming book on the treatment of aging as a medical condition. It is presented as putting forward a similar point of view to that found in Ending Aging by Aubrey de Grey and Michael Rae, meaning that the research and medical communities should place a relentless focus on damage and repair of damage. Aging is caused by an accumulation of molecular damage of a few distinct classes in and around cells, that damage spiraling out into a complex network of interacting downstream consequences.
Fully understanding that network, fully understanding the progression of aging, will take the rest of this century, or longer. The root causes of aging, these forms of damage that arise from the normal operation of a youthful metabolism, are much less complex in comparison, and, at this time, are far better understood. Therapies resulting in large benefits, such as significant extension of healthy life and significant reversal of age-related disease, are more likely to arise from work on the causes of aging than from work on understanding the complicated progression of aging. That much is in the process of being demonstrated by senolytics that destroy senescent cells.
Unfortunately, the research community is still largely focused on understanding the intricacies of aging, picking apart the details of the complex, damaged disarray of an aged metabolism, and aiming at no more than a modest slowing of aging. There is comparatively little interest in applying what is already known of the causes of aging. That must change.
Replacing Aging outlines how aging will soon be reversible as a result of the advances that are being made in regenerative medicine. The book explains the enormous complexity of aging and how the accumulation of myriad types of macromolecular damage in the body essentially precludes a pharmacological solution to the problem of aging. Nevertheless drugs remain the primary focus of the anti-aging field. Instead of drugs, a decisive way to erase all forms of age-related macromolecular damage at once would be by replacing old worn-out tissues with new young ones. As the book describes, an ability to replace all body parts seems more and more likely, if not inevitable.
Regenerative medicine is developing increasingly functional lab-grown cells, tissues, and organs that are being transplanted into patients today to treat diseases or repair damage. With continued improvements, cells and organs could be used in a more comprehensive manner to replace all body parts and reset the aging clock to near zero. Even the brain can be progressively replaced at a cellular level over time without a loss of self-identity. Existing examples demonstrate that complex brain functions can if given enough time change their neural substrates. And new brain cells added to old brains can form remarkably normal connection patterns. These findings together suggest protocols for brain rejuvenation. Thus, this book heralds the day in the near future when, if we choose to, we will be able to live much longer healthier lives as a result of replacements made possible by regenerative medicine.
Is Longevity actually just Replacing Aging?
"I was a bit of a weird kid growing up. I realized at a young age, in early elementary school in fact, that we are biological machines and that even if we stay healthy, we will eventually break down with time. I didn't like this and wanted to do something about it, so I knew I wanted to be a molecular biologist working on longevity before I even knew that the words "molecular biology" and "longevity" existed. Then in high school, I started reading on my own everything I could about how we function at a molecular level."
"Macromolecular damage is aging, at least from a biologist's perspective. Any other definition such as motor, immune, cognitive performance, for example can lead to claims of rejuvenation while the actual process of macromolecular and cellular decay proceeds without hinderance. This is an important point in the book because many in the aging field use only indirect markers of aging and are open to misinterpretation and false claims."
Aubrey de Grey's Review of "Replacing Aging"
The key to understanding that aging is not a mystery is to understand that it is not a phenomenon of biology, but of physics: it is fundamentally the same thing in a living organism as it is in a car, or an aeroplane, or any man-made machine. Once one realises that, it is a small step to realising that the approach we take - with dramatic success, when we try - to preserving the function of a car is sure to work just as well on the human body, once we develop the corresponding techniques to a level that matches the greater complexity of living organisms.
The author wastes no time in highlighting this key point - not merely in the abstract, but by getting down to specifics. He notes that the way we keep a car going is by preventative maintenance - damage repair. In other words, by maintaining the overall structure and composition of the car as it was initially. And that, of course, what inspires the title of the book, because preventative maintenance is largely about replacing worn or damaged parts.
The world needs far more books like Replacing Aging. In the past year or so, a few other gerontologists have published general-audience books explaining what this field is about and why it is so promising right now - and they all have different styles and will benefit different audiences to different degrees. In my view, Replacing Aging stands out as a shining example of how to get the public to break free of the fatalistic shackles that are so impeding the crusade to create a post-aging world.