One slice of the comprehensive package of biotechnologies needed to reverse the causes and consequences of degenerative aging involves next generation cell therapies. The aged body has lost needed cells, while other vital but small cell populations fall into a state of damage and dysfunction. Replacements will have to be generated, and cell therapies are how this goal will be achieved. These future therapies are presently in the early stages of development; they follow on from and will greatly improve on today's stem cell transplants. The introduction of new stem cells is the present best tool for achieving beneficial changes in native cell behavior, but the destination for this field is to discard the stem cells and simply make the desired changes directly. The stem cell therapies available now are a stepping stone to future treatments that directly repair cells and adjust their behavior in situ.
Cell therapies are neither more noteworthy nor more needed than any of the other items in the proposed rejuvenation toolkit, such as repair of mitochondrial damage and targeted clearance of metabolic waste, but they are considerably further along in the long path leading from first concepts to commercial therapies. A lot of money is available for stem cell research, and there is much to be said for making hay while the sun shines. Success here in steering groups within the community towards the treatment of aging will hopefully lead to successful businesses that branch out into other needed areas of development in rejuvenation biotechnology.
The 2014 World Stem Cell Summit was held last month in Texas. As you might expect, there is an ongoing discussion at such events prompted by those who are interested in going beyond merely treating age-related disease in its late stages, the traditional approach in medicine that has produced only marginal gains when it comes to extension of healthy life. These researchers want to turn the tools of regenerative medicine to tackle the causes of aging:
Medicine is the diagnosis, treatment, and, increasingly, hopefully, the prevention of what ails us. Most people's experience of medicine is likely focused on diagnosis and, unfortunately, the treatment of symptoms, the mitigation of the condition, with time bringing an amelioration of the problem. The excitement of regenerative medicine is the ability to replace or regenerate cells, tissues, or organs. So instead of a lifetime of taking injections, tablets, or using prostheses, patients actually become healthy again. Looking at tissue engineering, the classic approach is cells + scaffold = restored functionality.
It may be useful for researchers to think further out of the box regarding regenerative medicine than the areas that the term conventionally encompasses. Stem cell therapies are, in essence, a form of damage repair: they restore the number of cells of a given type that have been depleted, thus leading to ill-health. But tissue engineering restores not only cell number but also the structure of the extracellular matrix, among other things. Emerging technologies, often utilizing gene therapy or immune stimulation, powerfully complement these approaches. For example, in many cases they act to remove superfluous cells or detritus that the body is unable to eliminate naturally. The potential combined benefit of these therapies and classic regenerative medicine far exceeds the sum of its parts so there is considerable value in viewing the entire arsenal as facets of the same kind of medicine and thereby promoting cross-disciplinary thinking and research.
Clearly, heterochronic parabiotic studies have shown that the aged environment is hindering normal regenerative processes. How much these results can be recapitulated in humans is up for grabs right now. Anyone who works with rodents and humans knows that rodents are much more forgiving in terms of recovery from injury than humans. If the disease is one of aging, like age-related heart disease, macular degeneration, Alzheimer disease, or Parkinson's disease, we have no choice but to develop therapies that will work for older people. What is regenerative medicine if not the treatment of an event or condition that is increasingly likely to occur with years lived?