Aging, Just Another Disease

Aging is nothing more than a medical condition, and one that should be treated. There is a considerable amount of residual inertia on this topic, however, many people yet to be convinced that aging is anything other than set in stone, or that it is desirable to prevent the suffering and death caused by aging. At the large scale and over the long term, funding for medical research and pace of progress is determined by public support for the goals of that research. This is why we need advocacy, fundraising, and continued public discussion on the plausibility and desirability of building therapies capable of treating the causes of aging.

The concept of aging is undergoing a rapid transformation in medicine. The question has long been asked: Is aging a natural process that should be accepted as inevitable, or is it pathologic, a disease that should be prevented and treated? For the vast majority of medicine's history, the former position was considered a self-evident truth. So futile was any attempt to resist the ravages of aging that the matter was relegated to works of fantasy and fiction. But today, the biomedical community is rethinking its answer to this question. The controversy has been fanned, to a great extent, by one Aubrey de Grey, a Cambridge University-trained computer scientist and a self-taught biologist and gerontologist. Over the past decade, de Grey has undertaken an energetic campaign to reframe aging as a pathologic process, one that merits the same level of attention as, say, cancer or diabetes. Although many of de Grey's claims remain controversial - notably, that the first person who will live to 1,000 years old is already among us - I agree that we can and should pathologize aging. In fact, it seems we already have.

The human body comprises a number of different systems that each develop at its own pace. The nervous system seems to reach full maturity in our 20s, for instance, while the skeletal system may peak a decade later. Of course, this physiologic natural history is subject to environmental influence. Nevertheless, these environmental factors ultimately act on a foundation that, beyond a certain age, is inexorably deteriorating. There is a finite limit beyond which environmental factors cannot save us. The changes of aging vary in their specifics from one system to another, but common mechanisms are at work. For instance, wear-and-tear of joints results from depletion of articular cartilage, just as the thinning of skin is due to a loss of elastic connective tissue. Other age-related changes arise from errors in cellular activity or the accumulation of metabolic by-products, the probabilities of which rise over time. As these natural changes proceed, they lead to readily recognizable disease. The accumulation of fat in blood vessel walls provides a particularly good demonstration of this. Lipids are an essential part of our diet, but as processed lipids continue to accumulate in vessel walls, these vessels harden and narrow, eventually failing to supply the heart with enough blood. If the narrowing blocks vessels entirely, the heart is starved of blood, causing heart muscle death, or heart attack. This simplified example illustrates that perfectly normal processes that are critical to survival will quite naturally lead to disease. In a biological sense, the mere passage of time is pathological. Importantly, most of the early changes in this progression, such as high cholesterol, are symptomless. Yet they are precursors to life-threatening illness and are therefore considered pathologic entities in their own right, to be prevented and treated. The same can be argued of the more subtle and gradual damages of aging.

We can and should view these diseases, whose prevention and treatment are standard medical practice, as the clinical manifestations of natural age-related changes. Doctors have long targeted such changes to prevent disease. For instance, by recommending their patients limit the fat and carbohydrate content of their diets or take statin medications, doctors have strived to stave off heart disease. In so doing they unknowingly have been battling aging itself. Yet there are those who find this view of aging contentious, a reaction that likely stems from the misperception that the terms "natural" and "pathologic" are conflicting. There's a common yet unwarranted sense that these two terms are mutually exclusive; that what is natural can only be right, and what is pathologic cannot be natural. This is untrue. Because "natural" typically describes what conforms to the usual course of events, and "pathologic" describes what is harmful, the question posed in the opening paragraph presents a false dichotomy. Both "natural" and "pathologic" describe aging fairly. Thus, the controversy is largely semantic. If I were to replace the call for a "fight against aging" with an invitation to "combat age-related changes," I would expect a far more positive response. A call to "prevent the early stages of disease" would surely receive virtually unanimous support. I contend that the three phrasings are synonymous.



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