Finally, scientific knowledge of the possible individual risks or unwanted effects for GH-treated patients is still scant and warrants further research. In fact, it is not known whether long-term administration of growth hormone in the elderly is potentially harmful, particularly with regard to the risk of cancer [42, 47].
Research on interventions aimed at prolonging healthy lifespan and delaying the aging process includes reduction of oxidative damage and telome-rase activation. Recent studies have demonstrated that oxidative stress is a major determinant of lifespan in worms and flies, and that it can be counteracted by pharmacological intervention or genetic engineering techniques [48—52].
These studies have proved that strategies designed to counteract oxidative damage postpone the onset of senescence in invertebrate model organisms and significantly extend their lifespan.
However, these strategies did not induce a similar extension of the lifespan in mammals, where a more complex control system working via the aging process probably needs more specific and elaborate interventions . As reviewed by Harman, more sophisticated measures to reduce oxidative damage may include, among others, caloric restriction, antioxidant enzymes, superoxide dismutase SOD mimics, and dietary antioxidants .
At present, however, there is still scant evidence from human studies that interventions aimed at reducing oxidative stress damage might lead to a reduction in the rate of aging. There is growing evidence that telomere shortening limits the regenerative potential of organ cells during aging and chronic disease . Telomeres are stretches of noncoding DNA located at the ends of each linear chromosome, which play an important role in cellular senescence due to cell replication.
Each cell division results in ever-shorter telo-meres and altered telomere structure.
Thomas Perls MD, MPH, FACP
It was observed that activation of the telomerase enzyme regenerates telomeres, prevents replicative senescence and immortalises human primary cell cultures [54, 55]. The requirement of telomerase for human cell immortality, together with the observation that telomeres shorten with age, led to the hypothesis that telomere length may regulate cell replicative lifespan in vivo and eventually contribute to aging. The possibility of using telomerase activation to extend the regenerative potential of cells during aging and chronic disease depends on the effects of telomerase activity on tumour formation [52, 56].
Indeed, studies from telomerase-deficient mice suggest a dual role of telomere shortening and telomerase activation during cancer initiation and progression. None of the potential life extension interventions reviewed in the previous paragraph seems to provide conclusive evidence for future applications in humans. Although anti-aging predictions are much less reliable than their proponents claim, they have a tremendous impact on our understanding of aging and of the scope of biomedical research [11, 57]. Predictions of the feasibility and effectiveness of life extension interventions are tied to the belief that senescence should be considered a painful pathological phenomenon that has to be treated.
Such predictions maintain that the surge in population aging might contribute to socioeconomic stagnation or regression, and represents a collective and individual risk that should be counteracted through public health policies aimed at promoting anti-aging interventions . Although overoptimistic and hazardous, these predictions contribute to the construction of life extension as a biomedical goal, moored to a moral obligation to halt the aging process for the sake of the global population . The pursuit of this goal promises to bring previously unimaginable benefits to mankind, but generates significant worries as well.
Of all the arguments that have been put forward against these scientific developments, concerns about distributive justice offer the best prospects for a critical stance on anti-aging medicine and research. Even if life extension interventions should reduce the health care needs of the elderly population, problems may nonetheless arise for other basic resources, such as water or food.
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In fact it can be predicted that one of the consequences of an increase in the lifespan would be the increase in the population; if this is so, it seems likely that the scientific success of life-extending technologies would impose an unbearable burden on the environment and its resources. In any case, even if population is equal, the unbalance between the young and old may pose problems of intergenerational justice . The most evident is tied to pensions: the more the ratio between the generations favours the older ones, the more the younger will need to contribute to guarantee the social security of the former.
Of course, the younger will eventually be repaid for their sacrifices by a longer life, and the increase in the lifespan should also determine a prolongation of active and working life for the elderly; however, prolonging the working life of people with increased lifespans may not be beneficial for them, and may itself pose further problems of justice.
Large numbers of still working, much older people might create serious problems for the new generations striving for success or acknowledgment of their capacities. Another ethical worry is that, in all probability, life-extending technologies would be implemented for a relatively long time only in the more affluent countries that already have a high life expectancy; this would further widen the gap between resources and opportunities among sections of the world population . Some object to this consideration, noting that all scientific developments have first been implemented in some small areas of the world and have achieved widespread dissemination only with time; life extension techniques would simply follow along the same path .
It is not that we have found a therapy for some disease that previously went uncured, but that we have decided to cure something that previously was not considered a disease; and it could be argued that, as a matter of international justice, uncontroversial diseases with lost standing should take precedence, in the health care agenda, over new and controversial objects of care.
To this it has been answered that such a situation would not be so new and morally objectionable, since it is simply inevitable: it is a fact that, nowadays, there are dramatic differences in the life expectancy of people from different countries, and in fact we could say that parallel populations with very different life opportunities already inhabit our earth .
While unpleasant this fact is not unjust, because the fact that we cannot confer a benefit on everyone does not justify or mandate that we confer it on no one, but only that we try to extend it to everyone in due course. As a matter of fact, it is only the spread of certain technologies in the richest areas of the world that may lead to their benefits being extended to the less fortunate areas.
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Moreover, the advantages conferred by life extension techniques are not positional, that is, they are not inherently dependent on the fact that others are not enjoying them; therefore, fairness cannot dictate that we stop seeking them for ourselves, but only that we work to eventually attain universal provision.
A possible rejoinder is that past injustices do not justify new ones; it is true that analogous inequities have been justified in the past, since they were not considered relevant moral failings. However, it must be borne in mind that in those days the world was in no way thought of as a global community, and the injustice of differences in life circumstances among different regions could easily be underrated. Optimistic predictions of the feasibility and effectiveness of life extension should be critically reviewed in the light of their ethical and social implications.
Some anti-aging scientists claim that arguments against anti-aging medicine will simply be dismissed by research outcomes . The idea that life extension research will necessarily translate into what some judges interpret as a result i. Suppose we have laboratory advances that are promising for the future translation of laboratory work to the clinic.
This result would matter scientifically, but would not solve the ethical and social questions of life-extending interventions. Even if we should succeed in the laboratory, the problems of equitable access to such interventions, the impacts of the future implementation of life extension on health care systems, the risk of pressure to make use of life extension techniques — all these issues will still be with us. Ethical and social debate on these issues is therefore much needed, along with scientific research and discussion. No financial support and no other potential conflict of interest relevant to this article was reported.
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New Truth to the Fountain of Youth: The Emerging Reality of Anti-Aging Medicine on Apple Books
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