Role of Irisin in Endocrine and Metabolic Disorders—Possible New Therapeutic Agent?

Abstract

Irisin is a novel hormone that provides a possible solution for the treatment of metabolic disorders. Discovered in 2012 by Boström et al., irisin very quickly became an interesting subject in medical research. Irisin has been found in cerebrospinal fluid, the cerebellum, thyroid, pineal gland, liver, pancreas, testis, spleen, adult stomach, and human fetuses. Regarding the actions of irisin, both in animals and humans, the results are contradictory but interesting. Its capability to influence adipose tissue and glycemic homeostasis may be utilized in order to treat hypothyroidism, polycystic ovary syndrome, Prader–Willi syndrome, and other endocrine and metabolic disorders. Considering its osteogenic potential, irisin might be a therapeutic choice in diseases caused by a sedentary lifestyle. New data indicate that irisin treatment may serve in the treatment of severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) infection. Furthermore, several therapeutic agents, such as insulin, metformin, fenofibrate, exenatide, and melatonin, influence the concentrations of irisin in animal models or in humans. Nutritional factors including polyunsaturated fatty acids may also have an effect on irisin concentrations. While it may be “too good to be true,” irisin offers many opportunities for future research that would aim to find its optimal therapeutical role in endocrine and metabolic diseases.

Long-Term Effect of Exercise on Irisin Blood Levels—Systematic Review and Meta-Analysis

“…Such findings question all previous data obtained with these kits, and until these methodological aspects are resolved, studies relying on these measures should be carefully scrutinized. In summary, this review and meta-analysis may have some evidentiary support for the positive long-term effects of exercise on blood irisin levels, but more importantly, it points to the important methodological issues related to the actual detection of irisin [90], which should be considered when conducting research in this area [85]. In summary, our results confirm the general notion that exercise increases irisin levels in obese and older people.…”

“…More importantly, exercise including resistance training [44], aquaerobic training [50], endurance training [55], golf [61], low-intensity resistance training [66], high-intensity interval training [69], and treadmill walking [51] increased irisin blood levels in healthy older females and resistance training [82] in healthy older males, which may, in fact, protect against bone loss and muscle atrophy [6]. In this case, irisin might provide a therapeutic choice for treating diseases caused by inactivity (which often is the case for older adults), including osteoporosis and sarcopenia, or it may be used as a useful biomarker for the assessment of bone and muscle health as suggested by Leustean et al [85]. Especially, the older adult female population would benefit from this protective effect as they are prone to osteoporosis.…”

Irisin: An anti-inflammatory exerkine in aging and redox-mediated comorbidities

“…Numerous data have suggested the putative effect of increased irisin levels on reverting or retarding obesity and aging progression, based on renowned biomarkers, such as glycemia and total cholesterol levels (92). Previous studies have shown that irisin can act as a regulatory factor to control diabetes and obesity during aging (93).…”

The Potential Role of Exercise-Induced Neurotrophic Factors for Mental Health

“…Recently, irisin is thought to be a therapeutic hormone that can positively affect depressive behaviors through its effect on neuronal activities in the prefrontal cortex [84,85]. Moreover, some studies suggest that exercise-induced irisin ameliorates depressive symptoms by activating the PGC-1α-FNDC5/irisin pathway in the hippocampus [21,86].…”