Towards the Widespread Use of Gerotherapeutic Drugs to Slow Aging
Many compounds, small molecules, plant extracts, and so forth, have been found to modestly slow aging in mice. Given accumulating evidence from animal studies and human clinical trials, and that a sizable fraction of these compounds are already approved by regulators for other uses, or otherwise readily available, it is inevitably the case that physicians and the population at large will begin make use of these treatments in increasing numbers. This will happen, sometimes ahead of the science, sometimes behind it, sometimes to little benefit to patients, sometimes with enough of a benefit to matter. Navigating the options will become a great deal harder than it was, as we transition from an era in which little to nothing could be done to change the pace of aging, to one in which there are many options, with widely varying degrees of reliability, quality, and proof of reliability and quality.
The majority of people would like to live to the age of 120 years or more if their health remained good and nearly one half would like an unlimited lifespan. About one-third of people would be prepared to take life extension or anti-ageing therapies now. The possibility that a pill might prevent ageing and increase lifespan is tantalising for most people. As a result, anti-ageing and life extension therapies are often the focus for media hype despite the absence of definitive human data.
In this review, the term 'gerotherapeutics' is used to refer to drugs that target ageing biology, and that have been developed using similar approaches to those used to develop drugs for diseases. A major scientific endeavour is underway to find biological switches that can manipulate ageing. This research aims to discover new gerotherapeutic drugs that both reduce the burden of ageing-related diseases, and extend lifespan. There are many ageing-related diseases where the incidence increases exponentially throughout old age, including Alzheimer's disease, some cancers, ischaemic heart disease, ischemic stroke, and chronic obstructive pulmonary disease. The biological changes of ageing are a major risk factor these diseases. The hope is that gerotherapeutic drugs might reduce the impact of these ageing-related diseases with a single therapy.
Over the last two decades there has been a marked increase in the number of interventions reported to increase lifespan, and delay ageing and disease, in laboratory animals. However, the development of gerotherapeutic drugs is still in its infancy, and no gerotherapeutic drug has yet been shown to increase human lifespan or been licenced for an indication related to ageing. 'Anti-ageing' is a term mostly used to promote products that are not regulated or licenced. There are many drugs, supplements and other treatments that are marketed as anti-ageing and can be accessed direct-to-consumer from pharmacies or online. None of these treatments can support their anti-ageing claims with high quality clinical trials equivalent to those that are required for the registration of drugs for the treatment of individual diseases.
There is very little information about how many people are taking anti-ageing therapies and gerotherapeutic drugs or what they are taking. It is likely that most doctors, including geriatricians, will have some or many patients using these treatments without supervision, so will need to have some knowledge about them. This review focuses on gerotherapeutics that have an established basic scientific foundation and/or where there is the possibility of widespread use in the community. It also provides a summary of how these drugs are being discovered, using traditional drug discovery approaches, repurposing, or by investigating populations with exceptional longevity.