Ageing is characterised by the accumulation of molecular and cellular damage through time, leading to a decline in physical and mental abilities. Currently, society has experienced a rapid increase in life expectancy, which has led to an increase in age-associated diseases. Therefore, it is crucial to study the process of ageing to guarantee the best conditions in the final stages of life. In recent years, interest has increased in a myokine known as irisin, which is secreted during physical exercise. This polypeptide hormone is produced by various organs, mainly muscle, and once it is released into the blood, it performs a wide variety of functions that are involved in metabolic control and may be relevant during some of the diseases associated with ageing. The aim of this review is to highlight the recent studies of irisin, such as its mechanism of expression, blood release, distribution, tissue target and participation in various cellular metabolic reactions and the relationship with key anti-ageing pathways such as adenosine monophosphate-activated protein kinase, silent information regulator T 1, autophagy and telomerase. In conclusion, irisin is a key player during the ageing process and it could be a novel target molecule for the therapeutic approach to boost longevity pathways. However, more research will be necessary to use this promising hormone for this gain.

The aim of this study was to compare serum lipid profiles and ovarian gene expression between aged and younger female mice fed a control or a high-fat diet for 2 months. For this 16 female mice (C57BL/6) of 4 months (Young, n = 8) or 13 months (Old, n = 8) of age were used. The females were divided into four groups: (i) young females fed a normal diet; (ii) young females fed a high-fat diet; (iii) old females fed a normal diet; and (iv) old females fed a high-fat diet. Food intake was reduced (P < 0.05) in mice fed with a high-fat (2.9 ± 0.1 g) diet in comparison with control mice (3.9 ± 0.1 g). Body weight was higher for old females on the high-fat diet (35.1 ± 0.3 g) than for young females on the same diet (23.3 ± 0.4 g; P < 0.05). PON1 activity was lower in the high-fat than control diet group (114.3 ± 5.8 vs. 78.1 ± 6.0 kU/L, respectively) and was higher in older than younger females (85.9 ± 6.4 vs. 106.5 ± 5.3; P < 0.05, respectively). Females fed a high-fat diet had lower expression of Igf1 mRNA (P = 0.04). There was an interaction between age and diet for the expression of Gdf9 and Survivin, with lower expression in older females in both diets and young females that received the high-fat diet (P < 0.05). Concluding, the high-fat diet reduced the expression of ovarian Igf1 mRNA, and Gdf9 and Survivin mRNA in younger females, which can indicate lower fertility rates. High-density lipoprotein concentration and PON1 activity were higher in aged female mice.