The Holy Grail of Medicine: On the Mystery and Power of Stem Cells
They've already enabled paralyzed rats to walk, blind mice to see, and monkeys suffering from Parkinson's to show improvement. What's next?
Exactly how Richard Dalton, royal librarian for "Mad King" George III, made his startling discovery of the anatomical drawings of Leonardo da Vinci isn't known. What is known is that one day, around the time of the American Revolution, while removing the contents of a chest hidden away in Kensington Palace, Dalton uncovered hundreds of exquisite drawings by the Renaissance artist. Many drawings were of the human body -- of muscle and bone, lungs and hearts, legs and arms, sex organs and even fetuses in their maternal pod. Leonardo was known as much as an anatomist as a painter and an engineer, but until these drawings came to light, most of the tangible evidence was missing.
Worth many billions of dollars, Leonardo's drawings are considered the most prized holdings of the Royal Library at Windsor Castle. Yet their significance is priceless. Perhaps more than any other artifact, the anatomical drawings mark the end of the old world order and the beginning of the new. In the millennium between the fall of Rome and the rise of the Renaissance, the knowledge of nature existed in a largely fixed state. There was no place for curiosity in the lockdown mind-set of the Middle Ages. Then came the rediscovery of classical Greek and Roman culture and the call for reform; the rise of technology and science and printing as well as international trade; the exploration overland and overseas; the expansion of art; and, perhaps above all, the heretical but irresistible hunger for human progress. The Renaissance marked the passage of a world influenced by things unseen to a world influenced by things seen and understood through careful observation. Things like the human body.
Dalton's unveiling of Leonardo's anatomical drawings liberated a vital energy stored in the artist's compositions, an energy that continues to spur the human drive to discover. Never before had the body been subjected to such powerful examination. Never before had the particulars of what we are made of and how we work been rendered in such detail: how we breathe, how we move, how we sense our world, how we nourish and repair and re-create ourselves.
It is a curious quirk of history that these magnificent works of corporeal art should find their way to Windsor Castle. If you look out the windows of the Royal Library, you see Windsor Great Park, the site of sylvan reverie for the ancient Celtic people. Here, the Druids dreamed of everlasting life in a land called Tir Nan Og, where pain, disease, and decay did not exist. Tir Nan Og, the Land of Forever Young, was the Celtic expression of a universal theme in mythology, a dream that flows through all cultures and most religions: a dream of immortality through regeneration. Little did they dream, so long ago, that one day the name of their mythical land of eternal youth would reappear in a scientific and medical quest to extend life.
The ancient Celtic world of regeneration and Leonardo's legacy of scientific investigation during the Renaissance have converged in a new biology in the 21st century. The leading edge of this new biology, this biorenaissance, and the object of its exploration, is the most important element of all life: the cell. But not just any cell. More and more, modern science and medicine is and will be the province of the stem cell. Day by day, researchers are unveiling the mystery of the stem cell and its power for regenerating tissue that is healthy and repairing tissue that is diseased or damaged.
Stem cells are proving to be the silver bullet, the Holy Grail of medicine. They could alleviate all manner of suffering, whether it's caused by disease, injury, or genetic fate. Different stem cells possess different powers. Embryonic stem cells, for instance, have the capacity to re-create and repair any of the body's tissues and organs. Scientists often call these cells the "gold standard" of stem cell research. Adult stem cells, like those present in bone marrow, have the potential to repair some tissues and organs, but not all. Skin cells and other types of mature cells can now be genetically reprogrammed into stem cells that have many of the characteristics of embryonic stem cells. There may come a day when you go to a clinic, have some blood drawn, and have the white cells in your blood specimen reprogrammed and used to form your future stem cell tissue repair bank. If recent scientific advances are confirmed and extended, it is possible to imagine that your "personalized" banked cells will be able to repair your tissues and organs. You wouldn't have to worry about your body rejecting the cells because, after all, they are your own. One of the biggest challenges will be to make cell processing for therapies, which today can be expensive and must be approved by the U.S. Food and Drug Administration, generally affordable.
Stem cells have the potential to provide new and more effective treatments for diabetes, heart disease, genetic diseases, neurological diseases like Parkinson's and Alzheimer's, and even cancer; to repair debilitating injuries, such as spinal cord damage; to restore lost function, such as our sense of sight, hearing, smell, and touch, even limbs lost in combat. Already they have enabled blind mice to see, paralyzed rats to walk, and monkeys suffering from severe Parkinson's disease to show dramatic improvement in their symptoms. Stem cells could alter the way we look and feel, whether we wish to restore hair to our bald heads or to counteract the effects of aging on our skin, bones, and cartilage. In the eyes of enthusiasts, stem cells represent the best pathway toward the elusive fountain of youth, and not just for athletes.
Because so much of human disease is genetic in origin, and because stem cells loom larger all the time in diagnosis, treatment, and prevention of disease, stem cells will change the practice of medicine forever. The fields of stem cell biology and genomics are poised to reveal your health risks long before disease strikes and be able to take steps to minimize those risks. If disease strikes, treatment will be tailored to your unique genetic makeup and biochemistry. The code used by your stem cells to build you from the ground up will be available for tissue renovation or replacement due to disease, injury, or aging.
As the age-old dream of regeneration is being animated by stem cell research, scientists and bioengineers are re-creating components of the body's various systems from raw materials that exist within. These lab-created components -- a lymph node, a nerve bundle, a heart valve -- are invaluable for understanding human development as well as for refining regenerative medicine and designing biologically-based drugs. If the immune system, for instance, can be re-created piecemeal outside of the body and plumbed for its secrets of defense against disease and infection, stem cells indeed will have made a momentous contribution to human knowledge. Lab-recreated organs such as skin, bladders, and windpipes are already being used in patients, with bioartificial hearts, lungs, kidneys, livers, and intestine on the horizon, as we will see.
Yet depending on who you are and perhaps where you live, stem cell research can be seen as a means for preserving life or taking it. It can be seen as generating economic competitiveness or a moral decline, sustaining scientific prestige or the rise of amoral elites, ensuring personal freedom or bondage. It is both the agent of health and a widening avenue in the bioweapons arms race. It is imperative that we, as global citizens, understand the stem cell's awesome potential for life and death.