Here is an open access review of what is known of changes in the endocrine system that occur with aging. This is many steps removed from the low-level cellular and molecular damage that causes degenerative aging. It is a good example of a body-wide set of linkages between organs and signals and processes in which every change or failure in one component part will cause corresponding reactions in all of the other components.
A sizable field of medicine continues to focus on these changes, trying to find ways to shift levels of hormone signals to be closer to measures taken in youth. In past decades this has produced some legitimate treatments for a variety of age-related conditions that are better than nothing, but unfortunately also a fraudulent network of false "anti-aging" claims and purported therapies that cloud the waters and make any online discussion of this topic difficult. Where legitimate, as an approach it is acting at the wrong level, chasing after secondary and later effects in a very complex system rather than addressing the root causes of changing hormone levels. Consequently it has been challenging to produce more than marginal benefits, which is much as you'd expect if you're trying to tinker a broken system into better performance without actually fixing the breakage. Still, here as elsewhere, there is enormous inertia and resistance to the new concepts of addressing root causes rather than messing with metabolism in this way, and researchers continue to work on ever more sophisticated ways of trying to make the broken machinery perform:
Despite the contribution of sustained improvements in health and social wellbeing to linear gains in life expectancy within the developed world, much of older age is impaired by detrimental changes in body composition and function. Complex alterations in hormonal networks which maintain homeostasis and regulate reproduction, metabolism, nutrition and growth may underlie this poor adaptation to later life. The secretion of hormones decreases within most axes, the impact of which is augmented by a reduction in the sensitivity of tissues to their action, and normal circadian rhythms are lost. Endocrine axes manifest these changes with clinically identifiable losses of function such as those seen in the ageing of the reproductive system (menopause and andropause), the growth axis (somatopause) and axes involving the adrenal gland (adrenopause).The clinical sequelae of these changes are variable but include reductions in bone, skin and skeletal muscle mass and strength, derangement of insulin signalling, increases in adipose tissue and effects on immune function. Consequently, a number of studies have been carried out to assess the benefits of hormonal supplementation in the elderly, but the efficacy of these interventions remains relatively unclear. Both the menopause and subclinical thyroid disease demonstrate the difficulty in reversing endocrine changes in later life, with minimal impact from thyroxine therapy in subclinical hypothyroidism and multiple reports of harm resulting from hormone replacement therapy in peri- and post-menopausal women.
Given these findings, strategies to locally regulate hormone bioavailability by altering pre-receptor metabolism may offer greater therapeutic potential in the fight against age-related disease. This review aims to provide an overview of the ageing endocrine system and its potential impact on health and disease in the elderly. It will postulate that strategies to coordinate pre-receptor hormone metabolism and a greater understanding of putative hormonal longevity pathways may offer key new drug targets in the fight against ageing, and will argue against applying the conventional endocrine maxim of 'block and replace' to hormonal changes seen during ageing.
Link: http://www.karger.co...FullText/367692
View the full article at FightAging
