Biblically, the title refers to what God said in John’s Revelations in the New Testament, but for this article refers to the current hype over rejuvenation of body parts, and possibly in the future, even whole bodies by science, funded by fabulously rich middle-aged men in high-tech industries determined to keep life’s gig going much longer — at least for them. 

How? By plowing many billions of dollars into rejuvenation research, recruiting some of the world’s best scientists with generous financial incentives and supporting their work with equivalent resources, these champions of new-age industries hope to turn back the clock, and possibly reverse aging.

The names of some of the promotors and financial backers are familiar to readers: Elon Musk, Jeff Bezos, Rick Klausner, Peter Thiel, Yuri Milner, and Mark Zuckerberg, to name the leaders. So, no shortage of urgency, interest and cash.

The dream of reversing the arrow of aging isn’t new and may go back as much as a 100,000 years, possibly longer, and would have required an awareness of the universal cycle shared by all living creatures — namely birth, development, maturation, decline and death. 

Required too would have been considerable imagination and symbolic language skills sufficiently developed to share stories with one another about the meaning of life and death and possibly an afterlife in some form, as well as the possibility of supernatural forces and beings.

That seems to be the common template for most creation stories, myths and religions from ancient times to the present. But let’s move on from minds many thousands of years ago up to the present to focus on what happens following fertilization of an egg cell. 

The 2012 Nobel Prize in medicine or physiology was shared by two scientists: John  Gurdon and Shinya Yamanaka. It highlights the scientific roots for rejuvenation. 

Gurdon showed that a nucleus taken from a fully differentiated epithelial cell from the gut of a tadpole, implanted into an egg cell, whose own nucleus had been destroyed, had all the information necessary for that egg cell to develop (i.e. differentiate) into a tadpole. 

For his part, Yamanaka, showed that mature cells taken from an adult, could, in the presence of four transcription genes, be reverse-engineered to become pluripotent — that is, capable of differentiating into all the cells in the body, much as a fertilized egg can do. 

What’s going on here? What’s so special about those transcription genes and how could the genetic clock of mature cells be returned — rejuvenated — back to stem cells capable of differentiating into all the cells in the body? 

Obviously, there’s more to DNA than meets the eye. Our DNA contains all the genetic information to become every type of specialized cell in the body, but doing so requires differentiation, a finely tuned process of progressively activating and suppressing specific genes on the path to becoming, for example, a certain type of nerve cell or heart cell, while silencing other genes required to make other types of cells. 

That exquisitely orchestrated and timed process of selective gene activation and silencing is what makes the fertilized egg cell or reverse engineered cells so pluripotent and capable of differentiating into all the thousands of very different looking and behaving cells in the body. 

How are genes silenced or activated? In the case of silencing, methyl tags are attached to selected genes or activated by exposing specific genes. DNA is packaged in a protein called histone which depending on its shape, can hide or expose (activate) certain genes. 

Methyl tags and histones are nature’s way of silencing and activating genes and the basis of epigenetics — changes by which genes are selected or suppressed and explains why all cells have more or less the same DNA but can look and behave so differently.

Aging muddles things. For one, mutations slowly accumulate in DNA, the result of copying errors when cells divide again and again. That’s only part of the problem.

Other problems include shortening the ends of chromosomes — sometimes lopping off important genes in the process and probably most important for aging, are the accumulation of epigenetic errors.

Without epigenetic changes to differentiate different types of cells from one another properly, normal development wouldn’t be possible. But epigenetic changes can go wrong. 

Aging is associated with an accumulation of dysfunctional epigenetics: too many methyl tags in the wrong place and changes in the way histones are wrapped around the DNA can change the effectiveness of genes associated with aging.

Too many accumulated epigenetic changes, hobbles cells and they can’t function as well as they did decades before because of all the epigenetic baggage they’ve accumulated through chance and environmental stresses such as radiation from the sun in the case of the skin and eyes or chronic inflammation.  

Readers can see where this is going. Rejuvenation involves reversing the cumulative effects of aging on cells to a much younger stage when all those cells were much healthier.

In a nutshell, that’s what rejuvenation is all about: making old cells, old systems, old organs including our brains, young again. Or at least, that’s the hyped hope. 

Nest week, we’ll have a look at how rejuvenation works in laboratories — or does it?

Dr. William Brown is a professor of neurology at McMaster University and co-founder of the InfoHealth series at the Niagara-on-the-Lake Public Library.