Although life expectancy at age 60 is undoubtedly increased in high-income countries, elderly subjects spend several years in prolonged disability. Among the multiple chronic disorders possibly leading to disability, the geriatric syndrome of frailty is a significant public health priority.
It is a highly problematic state of vulnerability characterised by decreased reserve and diminished resistance to stressors (Clegg et al., 2013) (Rodríguez-Mañas, 2013). While early detection and prevention of frailty are crucial in this scenario, unfortunately no healthcare programmes or pharmacological treatments are available for frail older people. Increasing evidence recognises sarcopenia, a state of age-related quantitative muscle loss (Cruz-Jentoft – Zamboni 2010) as the central biological substrate of frailty (Landi F, 2015). The prevalence of sarcopenia increases with age and has been estimated in the order of 5 to 13% in the 60-70-year-old population, rising up to 50% among subjects aged 80 years or older (Janssen, 2011). Reduced relative muscle mass is significantly and independently associated with disability in older subjects (Landi F, 2015).
A sarcopenia-linked global health challenge in the elderly population is the obesity epidemics. Intramyocellular lipid accumulation and/or intermuscular adipocyte formation occur in muscle of obese patients, contributing to functional impairment. In this scenario, the hypothesis is emerging that lean mass loss, together with muscle fat accumulation and metabolic derangement, with or without the presence of obesity, are at the core of the functional defects of the elderly frail population (Buch, 2016).
While the complex, interlinked causal mechanisms are far from being established, age-dependent decrements in mitochondrial function play a key role in the frail phenotype (Buch, 2016). Indeed, mitochondrial dysfunction (e.g., changes in mitochondrial biogenesis and dynamics, reduced mithocondrial hormesis, and impaired crosstalk among mitochondria and other cellular organelles) take part to the energetics decline of the elderly (Nisoli & Valerio, 2014; Valerio & Nisoli, 2015). Thus, a critical necessity in sarcopenic elderly people is developing products able to promote both mitochondrial boosters and anti-obesity programs. PD candidates are being developed to answer these health requests.