Reasons for optimism - Ageing
While we can be optimistic that advances in medicine and healthcare could enable us to live longer, healthier lives, we eventually come up against the lifespan barrier that limits the number of years before the body’s deterioration with age finally ends its life. The indications are that many more people will live to pass the 100-year milestone, and some suggest that perhaps 120 years might supplant the traditional biblical “three score years and ten.” But some researchers are looking into ways that might delay, or even reverse, the ageing process to the extent that people might live for hundreds of years, not aged and relatively helpless years, but vigorous, youthful years.
There are several approaches that show promise, including ones that have lengthened the lifespan and apparent youthfulness of test mice in laboratory experiments. These include measures to prevent the shortening, or even lengthen, the telomeres, the same short repeated DNA sequences at the end of chromosomes. They have been compared to the plastic tips on shoelaces that prevent them fraying. Shorter telomeres correlate with ageing, and longer ones with longevity. They become shorter as the body ages and telomerase, the enzyme that repairs the telomeres, becomes depleted and degraded. But there are procedures that can delay or prevent this, and these include taking control of weight, exercise, stress, and diet, and perhaps taking supplements. Studies have shown that, on average, subjects who do this have longer telomeres than those who do not.
A further class of research is looking at senolytics, a class of small molecules that can target senescent cells, the damaged and ineffective cells that increasingly proliferate as the body ages, causing inflammation, and turning healthy cells senescent and leading to tissue damage. When senolytics are used to remove these cells in mice, the animals treated have achieved longer, healthier lifespans, and the research now has turned to repeating these successes in human subjects. Some of the scientists involved in this research have volunteered themselves as guinea pigs to monitor the effectiveness of the process.
The people working along such lines of approach are breaking new ground by attempting to deal with ageing itself, instead of attempting to treat, one by one, the diseases and conditions that come with it. Their outlook is that it is ageing, with its cell and tissue damage as the body loses the ability to repair itself, that leads to the cancers and heart diseases that degrade or terminate lives. By treating ageing itself, their hope is that the body can be kept or restored to an indefinitely youthful state. In short, instead of concentrating on treating the diseases and infirmities that come with age, they are seeking to have the body retain its ability to do that itself.
This raises the prospect of extending the human lifespan to perhaps hundreds of years, which could bring social problems in its wake. If youthful and vigorous older people remain active and in place, this could close off opportunities for advancement and promotion by younger people. And it might retard progress as people loyal to their old ideas do not leave the stage and make way for those prepared to embrace new ones. No doubt solutions to such problems will manifest themselves as people learn and adapt to new circumstances, but it helps to anticipate that developments such as these will bring about a radically different world. The prospect of lives not debilitated or depleted by age is an attractive, optimistic one, the more so if humanity prepares in advance for the changed world it will engender.