Serum irisin and myostatin levels after 2 weeks of high-altitude climbing

Abstract

Exposure to high-altitude hypoxia causes physiological and metabolic adaptive changes by disturbing homeostasis. Hypoxia-related changes in skeletal muscle affect the closely interconnected energy and regeneration processes. The balance between protein synthesis and degradation in the skeletal muscle is regulated by several molecules such as myostatin, cytokines, vitamin D, and irisin. This study investigates changes in irisin and myostatin levels in male climbers after a 2-week high-altitude expedition, and their association with 25(OH)D and indices of inflammatory processes. The study was performed in 8 men aged between 23 and 31 years, who participated in a 2-week climbing expedition in the Alps. The measurements of body composition and serum concentrations of irisin, myostatin, 25(OH)D, interleukin-6, myoglobin, high-sensitivity C-reactive protein, osteoprotegerin, and high-sensitivity soluble receptor activator of NF-κB ligand (sRANKL) were performed before and after expedition. A 2-week exposure to hypobaric hypoxia caused significant decrease in body mass, body mass index (BMI), free fat mass and irisin, 25-Hydroxyvitamin D levels. On the other hand, significant increase in the levels of myoglobin, high-sensitivity C-reactive protein, interleukin-6, and osteoprotegerin were noted. The observed correlations of irisin with 25(OH)D levels, as well as myostatin levels with inflammatory markers and the OPG/RANKL ratio indicate that these myokines may be involved in the energy-related processes and skeletal muscle regeneration in response to 2-week exposure to hypobaric hypoxia.

Vitamin D supplementation improves SIRT1, Irisin, and glucose indices in overweight or obese type 2 diabetic patients: a double-blind randomized placebo-controlled clinical trial

“…A study in 2017 showed serum irisin levels were decreased after 2 weeks' mountain climbing. The possible reasons were exposure to hypoxia, the energy-related mechanisms, and the revitalization of musculoskeletal cells in response to hypoxia [39].…”

“…In contrast, some studies of VD effects reported a significant improvement in fasting serum insulin [34,[42][43][44]. The potential mechanisms may be the presence of VD receptors (VDRs) in pancreas cells and expression of 1alpha-hydroxylase in them [37] and the existence of some elements on human insulin promotors that respond to VD and can activate insulin gene transcription [38][39][40].…”

Irisin Recovers Osteoarthritic Chondrocytes In Vitro

“…Duration of exercise training and environmental factors both influence the levels of circulating irisin. A large meta-analysis reported a decrease of circulating irisin in healthy individuals undergoing either endurance or resistance chronic exercise (>8 weeks) [59], whilst another study showed a reduction in irisin levels after two weeks of climbing at high altitude-hypoxia [60]. To date, no evidence concerning the ideal type of exercise or training protocol for osteoarthritic joints is available.…”

Effects of whole-body cryotherapy on 25-hydroxyvitamin D, irisin, myostatin, and interleukin-6 levels in healthy young men of different fitness levels

“…Despite not finding any studies on the effect of cryotherapy on the level of vitamin D in the available literature, we presume that the observed changes in 25(OH)D levels might be attributed to the role of vitamin D in the inflammatory response, which is indicated by the inverse relationship between changes (Δ 1-2 ) in concentrations of 25(OH)D and hsCRP, noted 30 minutes after the first WBC treatment in the HPhL group (Table 3). Studies have shown that vitamin D may possess natural antioxidant and anti-inflammatory properties 24,32,33 .…”

“…IL-6 is a multifunctional protein produced by immune cells of the endothelium, connective tissue, adipose tissue, and skeletal muscle 22 . Factors inducing the expression of the IL-6 gene in skeletal muscle include reactive oxygen species 23 .Our previous studies showed that exposure to hypobaric hypoxia for 2 weeks during a climbing expedition decreased the level of 25-hydroxyvitamin D (25(OH)D) in the human body 24,25 . Other authors have not unequivocally concluded whether the reason for this decrease in 25(OH)D levels in blood serum is due to hypoxia and the related production of pro-inflammatory factors, exercise-induced muscle damage, or/and low ambient temperatures.…”