Does iris(in) bring bad news or good news?

Area of Science:

• Endocrinology and Metabolism
• Exercise Physiology
• Molecular Biology

Background:

• Irisin is a myokine released during physical activity, known to induce white adipose tissue (WAT) browning.
• In rodents, irisin influences metabolic regulation, energy expenditure, and glucose homeostasis.
• Emerging evidence suggests irisin mediates various exercise-induced benefits, including effects on bone, liver, and cognition.

Purpose of the Study:

• To review the history, expression, and known functions of irisin.
• To analyze the current understanding of irisin's role in human health.
• To highlight limitations and controversies surrounding irisin research in humans.

Main Methods:

• Literature review of studies on irisin in animals and humans.
• Analysis of data regarding irisin's effects on metabolic processes and other physiological systems.
• Examination of evidence supporting and challenging irisin's functions in humans.

Main Results:

• Irisin's presence in humans has only recently been confirmed, leading to ongoing research.
• Potential beneficial effects in humans include improved bone mass, reduced hepatic lipid accumulation, and enhanced cognitive function.
• A significant limitation is the unidentified irisin receptor in both humans and animals, hindering mechanistic understanding.

Conclusions:

• Irisin is a key mediator of exercise-induced benefits, with growing evidence for its role in human health.
• Further research is crucial to elucidate irisin's precise mechanisms of action, particularly its receptor interactions.
• Understanding irisin's functions in humans is essential for translating exercise-related health benefits into therapeutic strategies.