Life extension science
Life extension science, also known as experimental gerontology, is a multidisciplinary field focused on understanding and potentially slowing the aging process to extend human lifespan. It encompasses various areas of medicine and biology, including pharmaceuticals, gene therapy, and regenerative medicine. Researchers in this field explore both established methods, such as improving health outcomes through disease prevention, and hypothetical advancements, including molecular repair technologies, organ replacements, and even concepts like mind uploading.
The study of aging involves complex biological processes, including cellular damage, DNA replication errors, and the decline in the functionality of cells. As people age, they become increasingly susceptible to age-related diseases, highlighting the necessity for ongoing research in life extension. Current strategies range from dietary approaches to gene therapy, although many proposed methods remain experimental and unproven.
Moreover, the pursuit of extending human life raises significant ethical and practical questions, such as the implications for healthcare, retirement, and socioeconomic disparities in access to life extension technologies. Overall, life extension science seeks to enhance both the quality and duration of human life, while grappling with the challenges that longer lifespans may present to society.
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Life extension science
Life extension science, or experimental gerontology, is the study of how to slow down the aging processes in order to extend the human lifespan. The field encompasses numerous areas of medicine and biology, including pharmaceuticals, regenerative medicine, gene therapy, and stem cells. Additionally, experimental or hypothetical areas such as molecular repair, xenotransplantation, artificial organs, cryonics, and even mind uploading are included.
There is a large global industry aimed at fighting old age, ranging from skin care treatments and hair loss preventatives to hormone replacement therapies and so-called antiaging supplements. Most medical experts find little that is legitimate about these commercial enterprises; the best of them either simply reduce the effects of aging (reducing facial wrinkles, slowing hair loss, restoring erectile function) or promise a somewhat healthier life while alive, without any proven effect on lifespan. The existence of this larger industry makes it hard to perceive the legitimate but so far mostly hypothetical science of life extension.
Background
In 2013, the top five causes of death in the United States apart from accidents were heart disease, cancer, chronic lower respiratory disease, stroke, and Alzheimer’s disease—five conditions that, ignoring genetic predispositions, are more and more likely to occur in patients the older they live. Aside from certain types of cancers, these diseases do not affect younger people in significant numbers. It appears, then, that even when a population’s overall health is raised to a level in which people experience relatively long lifespans by historical terms, the effects of aging naturally raise the risk of disease and death. Even individuals who are remarkably healthy well into old age eventually experience physical decline, and living longer than one hundred years is relatively rare.
The process of aging, or senescence, is not well understood. It involves not one process but many, including damage to cellular contents by free radicals, loss of proteostasis, telomere attrition, DNA replication errors, dysfunction of mitochondria, and senescence of cells themselves, meaning that normal cells cease to divide, damaging DNA. The supplement industry popularized the free radical theory of aging, which focuses on the role of free radicals in damaging cells through oxidation, and therefore the possibility of antioxidants in preventing this damage. The free radical theory was originated by Denham Harman, who founded the American Aging Association in 1970, and was a pioneer in the life extension movement. Clinical trials have had mixed results in supporting the theory, however, and in several cases antioxidant treatments have actually increased mortality, not decreased it.
Another theory of aging is the DNA damage theory of aging, which proposes aging to be the result of the accumulation of naturally occurring DNA damage due to replication errors, ultraviolet light exposure, and other factors. DNA damage is thought to contribute to both cellular senescence and apoptosis, two aging processes, as well as increase cell dysfunction. Proponents of this theory point to specific DNA damage–related effects in various parts of the body (primarily the muscle tissue, toxin-filtering organs, and brain) that correlate with the observed effects of advanced age.
Overview
Modern medicine is already a life extension science, in that many diseases that were once terminal are now preventable or curable. Patients with some terminal conditions are able to live much longer than in eras past, in many parts of the world infant mortality has been reduced from commonplace to a rare tragedy, and average lifespans have increased. The quality of life of the elderly has overall been greatly improved as well.
Yet researchers continue to question why one individual may live well into their hundreds, while another seemingly equally healthy person dies of natural causes years earlier. Scientists also look to other organisms with extensive lifespans as proof that it is biologically possible to live far longer than any human ever has. Those interested in life extension science seek ways to continually extend humans’ maximum lifespan and the average lifespans of populations.
Proposed strategies for life extension are extremely varied. When nanotechnology was still only hypothetical, one of its first proposed uses was to design molecular-sized machines that could repair human cells in the body in order to lengthen human lifespans, and refinements of this general strategy continue to be formulated. Numerous pharmaceutical treatments and behavioral methods have been developed and tested, ranging from calorie restriction diets to vitamin supplements to specific immunosupressants and enzymes. Gene therapy has provided the possibility of correcting genetic mutations, as well as introducing modifications that might increase the lifespan. Yet these methods remain experimental and none have been proven effective.
Life extension need not limit itself to preserving the body. Indeed, many life extension adherents all but disregard the possibility of doing so, in favor of replacing the body in one sense or another. At the simplest level, there is organ replacement. There has already been considerable success both with organ transplants and artificial organs, but development of durable, efficient replacements for the liver, kidneys, lungs, and heart would do much to prolong many lifespans. A step beyond replacing organs would be augmenting the body with cybernetic implants, possibly incorporating nanotechnology. Implants could detect medical problems as they occur and even respond to some problems with appropriate solutions, like an augmented immune system. Beyond even this step is the idea of freeing the lifespan from biology by transferring human consciousness to a nonbiological system, a process often called mind uploading. The resulting system could then be retransferred to a healthy young clone of the original human body or run like software on a robotic body—or even exist in some other sense, without what people in the twenty-first century think of as a body at all, potentially achieving immortality.
Extending the human lifespan raises many practical and ethical questions. Some of the obvious ones deal with economics: if humans live longer, should the retirement age change, and the age at which senior-related benefits are made available? How will this change the job market? What other demographic changes will be triggered by people having longer lives (or even seemingly infinite ones), and can natural resources sustain such a population? The question of access to whatever technology enables life extension is another great concern, with many observers questioning what would happen to society if such technology becomes available only to the wealthy.
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