Anti-aging hormone receptors – Scientists believe that hormone receptors may regulate the effect of nutrition on life expectancy not only in roundworms, but perhaps also in human beings
01 August 2013 The Max Planck Institute for Biology of Ageing/ Max-Planck-Institut für Biologie des Alterns
A reduced caloric intake increases life expectancy in many species. But how diet prolongs the lives of model organisms such as fruit flies and roundworms has remained a mystery until recently.
Scientists at the Max Planck Institute for Biology of Ageing in Cologne discovered that a hormone receptor is one of the links between nutrition and life expectancy in the roundworms.
The receptor protein NHR-62 increases the lifespan of the animals by twenty per cent if their calorie intake is reduced.
Furthermore, another study showed that the hormone receptor NHR-8 affects development into adulthood as well as the maximum lifespan of the worms. It may be possible that receptors related to these are also responsible for regulating life expectancy in human beings.
The roundworm Caenorhabditis elegans lives only about 20 days. This makes it an ideal research subject, as the complete lifecycle of the worm can be studied in a short time. Also, the worm consists of less than a thousand cells, and its genetic make-up has been extensively analysed, and contains many genes similar to humans. The scientists in Adam Antebi’s team at the Max Planck Institute for Biology of Ageing use Caenorhabditis elegans to find out how hormones influence ageing. They are particularly interested in hormone receptors that reside in the cell nucleus, which regulate the activity of metabolic genes.
Their results indicate that the receptor NHR-62 must be active for reduced dietary intake to fully prolong the life of worms. If NHR-62 is inactive, Caenorhabditis elegans will live 25% longer under dietary restriction than if this receptor is inactive. “It seems that there is an as yet unknown hormone which regulates lifespan using NHR-62. If we can identify this hormone and administer it to the worm, we may prolong its life without having to change its calorie intake”, Antebi explains.
A restricted diet also affects the expression of genes dramatically: out of the approximate 20,000 worm genes, 3,000 change their activity, and 600 of these show a dependence on NHR-62. It follows that there are many other candidates for improving life expectancy.
Since humans have receptors similar to NHR-62, so-called HNF-4α, the Max Planck scientists suspect that the hormone receptors may not only control the maximum lifespan of roundworms, but might affect human beings as well.
However, nutrition also affects lifespan in several other ways. Another study by the scientists has shown that worms lacking the hormone receptor NHR-8 will remain longer in a pre-pubertal stage before they reach adulthood. They also die earlier than animals with this receptor. NHR-8 is a nuclear receptor, responsible for the animal’s cholesterol balance. “Without it, the worm cannot produce enough steroid hormones from the cholesterol and therefore reaches sexual maturity later on.
In addition, its fatty acid metabolism changes and its life expectancy drops”, explains Antebi. Receptors similar to NHR-8 can be found in human beings too. Conceivably cholesterol metabolism could therefore regulate physical development and affect life expectancy in humans as well.
For a short video on intracellular receptors for testosterone, check out Intracellular Receptors & Steroid Hormone Testosterone on YouTube.
Twelve weeks of training geared towards improving muscular power in older people are highly effective for improving their functional capacity and quality of life, as shown by the studies carried out by the â€œBiomechanics and Physiology of Movementâ€ research group at the Public University of Navarre led by Professor Mikel Izquierdo-Redin.
The results of these pieces of research, conducted in collaboration with the University of TrÃ¡s-os-Montes e Alto Douro (Portugal) and the Federal University of Rio Grande del Sur (Brazil), have been published in two articles in the scientific journal Experimental Gerontology: â€œEffects of high-speed power training on functional capacity and muscle performance in older womenâ€ and â€œStrength prior to endurance intra-session exercise sequence optimizes neuromuscular and cardiovascular gains in elderly menâ€.
The results confirm the hypotheses raised in recent decades by various researchers with respect to the capacity of power training to prevent or reduce their loss in older people. As Mikel Izquerdo explains, â€œIt has been established how people between 60 and 70 years of age who participated in a four-month training program to develop muscular strength and mass regained the functional capacity and muscle power of twenty years previously; in other words, they were the same as their peers who started the same training program at the age of 40.â€
In his view, there are two good reasons why we should encourage people to undertake regular physical exercise from the age of 50 onwards:
- â€œFirstly, because it is a cornerstone in the prevention and treatment of cardiovascular and other chronic diseases; andÂ
- secondly, because it plays a crucial role in preventing and treating the decline in functional capacity, which tends to emerge in a highly significant way at this age.”
In this respect, the researcher insists that physical exercise would be a plausible measure for improving the functional capacity of older people and for reducing healthcare expenditure.
The interest in aging has grown exponentially over the last few decades and some of its aspects, like disability or fragility, have become the center of attention in basic, clinical and population research. In Spain during the last century the population doubled, the number over 65 increased sevenfold, and the number of octogenarians thirteen fold.
The loss in muscular mass and muscular qualities in aging is directly related to the reduction in mobility and the capacity to perform the activities regarded as basic or instrumental for daily life. â€œThis loss of muscular mass and qualities (peripheral muscular dysfunction) has manifested itself in cardiovascular and respiratory diseases, within the multifactorial process of these diseases and delimits the participation of the patients in activities in daily life, and also contributes towards mortality risk.â€
In this context the interventions that have proved to be the most effective in delaying disability and other situations that arise with aging are the multi-component physical exercise programs and, above all, power training. These exercises have also shown themselves to be useful in events frequently associated with falls, cognitive deterioration and depression.
Relatively intense physical training has to be adapted to the patient’s functional capacity and is accompanied by significant increases in muscular strength, aerobic physical condition, joint mobility, motor skill, self-esteem and longevity, irrespective of age or sex, as long as the intensity and duration of the training period are sufficient.
The initial increases in strength can be as high as 10-30% during the first weeks or 1-2 months of training, both in middle-aged and elderly people.
A second study has been able to show how in older people the prescribing of a training programme that combines muscular strength and endurance exercises is one of the best strategies for improving neuromuscular and cardiovascular function, while improving functional capacity and promoting the enhancement of health and qualify of life.
Likewise, it has been observed that the carrying out of muscular strength exercises before cardiovascular endurance exercises is the best sequencing for obtaining the maximum benefits from a physical exercise program.
â€œThese results,â€ concludes Professor Izquierdo, â€œare of great practical interest for promoting health and quality of life through the participation of older people in exercise programs.â€
- Full bibliographic information Eduardo Lusa Cadorea, Corresponding author contact information, E-mail the corresponding author, Mikel Izquierdob, Cristine Lima Albertona, Ronei Silveira Pintoa, Matheus ConceiÃ§Ã£oa, Giovani Cunhaa, RÃ©gis Radaellia, Martim Bottaroc, Guilherme Treis Trindadea, Luiz Fernando Martins Kruela
“Strength prior to endurance intra-session exercise sequence optimizes neuromuscular and cardiovascular gains in elderly men”. Experimental Gerontology. Received 31 October 2011. Revised 21 November 2011. Accepted 30 November 2011. Available online 9 December 2011. Section Editor: Christiaan Leeuwenburgh.