Aging is the inevitable accumulation of physical changes in organisms over time, which progressively increases the risk of disease and mortality.
Advancing adult age is associated with profound changes in body composition. One of the most prominent of these changes is sarcopenia, defined as the age-related loss in skeletal muscle mass, which results in decreased strength and aerobic capacity and thus functional capacity. Sarcopenia is also closely linked to age-related losses in bone mineral, basal metabolic rate and increased body fat content.
Skeletal muscle is a highly malleable tissue, whereby muscle mass is determined by a fine-tuned network of muscle growth and degradation pathways. While the activation of the phosphoinositide 3-kinase (PI3K)/Akt pathway by Insulin-like growth factor-1 (IGF-1) leads to muscle hypertrophy, its inhibition by myostatin, a member of the transforming growth factor-β (TGF-β) family, generally lead to muscle atrophy and inhibits muscle differentiation. Also other TGF-β family members such as activin A and growth differentiation factor-15 (GDF-15) seem to have a negative impact on skeletal muscle growth.
With these aspects in mind it is not surprising that many of these molecules are suggested as blood-based biomarkers of aging. In older women, IGF-1 correlates negatively with age and positively with muscle mass while GDF-15 is positively associated with age and negatively with muscle mass. Contrasting results have been detected for serum myostatin levels which are negatively correlated to muscle mass in male patients with chronic obstructive pulmonary disease.
At nutritional level total energy intake is decreasing with the aging process which emphasise the importance of a high nutrient density. Furthermore organs are losing function which leads to impairments in bioavailability and activation of various nutrients such as vitamin B12 or D.
Here it is important to assess levels in urine, plasma or sometimes very specifically at cellular level such as for folic acid.
Further mechanisms that contribute to the aging process and the development of chronic, age-associated diseases include increased levels of DNA damage, genotoxicity, oxidative stress, and shorter telomeres. Latter parameters also have a close link to nutrient status and are changed at weak storage levels.
The talk will summarize nutritional and muscular biomarkers for aging, link them to changes based on lifestyle intervention programs in elderly and will also specifically focus on the cellular and molecular level. One final aspect will be longevity and changing biomarkers of elderly above life expectancy compared to subjects below life expectancy.
Funding Source(s): University of Vienna via the Research Platform Active Ageing and the Anniversary Fund of the Austrian National Bank (No. 14541).