Introduction
In humans, muscle mass decreases after its peak in the third decade of
life [1]. Muscle mass is important for physical and metabolic
fitness regulation. The development of sarcopenia is an important risk
factor for the development of frailty, loss of independence and physical
disability in the elderly and is associated with shorter survival in
critically ill patients [2]. In the 8th decade, men and women can
lose about 7 and 3.8 kg of muscle mass, respectively, with increased
intra-abdominal fat [3].
In this context, the number of disabilities due to age is expected to
double by 2060. Muscle mass is important for physical fitness and
metabolic regulation [4]. In this scenario, the development of
sarcopenia is an important risk factor for the development of frailty,
loss of independence and physical disability in the elderly and is
associated with lower survival in critically ill patients. The
pathophysiology of sarcopenia is multifactorial and may be influenced by
reduced caloric intake, neurodegenerative diseases, intracellular
oxidative stress, hormonal disorders, and others. In this sense, the
decline in fat-free mass correlates with the decline associated with the
age of growth hormone (GH) secretion. Thus, GH secretagogue (Ibutamoren
- MK-677) as the first orally active ghrelin mimetic may increase
pulsatile GH secretion in the elderly [5].
Therefore, the present study aimed to determine whether oral MK-677 in
healthy elderly would increase GH and insulin-like growth factor I
(IGF-I) levels, prevent the decline of muscle mass, and decrease
abdominal visceral fat (AVF) with acceptable tolerability.