Piotr Kaczka, Małgorzata Magdalena Michalczyk, Rafał Jastrząb, Mateusz Gawelczyk and Katarzyna Kubicka
Beta-hydroxy-beta-methylbutyrate (HMB) has been used extensively as a dietary supplement for athletes and physically active people. HMB is a leucine metabolite, which is one of three branched chain amino acids. HMB plays multiple roles in the human body of which most important ones include protein metabolism, insulin activity and skeletal muscle hypertrophy. The ergogenic effects of HMB supplementation are related to the enhancement of sarcolemma integrity, inhibition of protein degradation (ubiquitin pathway), decreased cell apoptosis, increased protein synthesis (mTOR pathway), stimulation of the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis and enhancement of muscle stem cells proliferation and differentiation. HMB supplementation has been carried out with various groups of athletes. In endurance and martial arts athletes, HMB supplementation revealed positive effects on specific aerobic capacity variables. Positive results were also disclosed in resistance trained athletes, where changes in strength, body fat and muscle mass as well as anaerobic performance and power output were observed. The purpose of this review was to present the main mechanisms of HMB action, especially related to muscle protein synthesis and degradation, and ergogenic effects on different types of sports and physical activities.
Antonio Paoli, Pasqualina Cancellara, Pierluigi Pompei and Tatiana Moro
linked to higher protein intake compared to other KD in animal models ( Roberts et al., 2016 ; Roberts et al., 2017 ). Another target of metabolic changes induced by KD is Akt. Akt is involved in different cellular processes such as cell growth, proliferation, apoptosis, transcription, angiogenesis, migration, and glucose metabolism and it is also activated following a great number of stimuli among which insulin and insulin-like growth factor are of greatest importance ( Sandri et al., 2013 ). In turn, Akt acts on target proteins that include glycogen synthase kinase
Cornelia Nitipir, Cristina Orlov-Slavu and Lucian Alecu
progression and induced apoptosis as well as autophagy depending on ERK1/2 activity in human chondrosarcoma cells. Cell Death Dis. 2014; 5,e979.
20. Kostine M, Cleven AHG et al. Analysis of PD-L1, T-cell infiltrate and HLA expression in chondrosarcoma indicates potential for response to immunotherapy specifically in the dedifferentiated subtype, Modern Pathology advance online publication, 17 June 2016.
Maria Jastrzębska, Mariusz Kaczmarczyk, Małgorzata Michalczyk, Łukasz Radzimiński, Piotr Stępień, Joanna Jastrzębska, Dorota Wakuluk, Arturo Díaz Suárez, Guillermo Felipe López Sánchez, Paweł Cięszczyk, Piotr Godlewski, Paweł Król and Zbigniew Jastrzębski
processes, showing antiinflammatory, anti-apoptosis, anti-fibrinolytic, and even antitumor activity ( Lai and Fang, 2013 ).Moreover, its role in cell differentiation and inhibition of cell proliferation was proven ( Bikle, 2009 ).
The effects of vitamin D on various life processes and functions of organs as well as the possibility of its application in disease prevention or treatment were the object of many scientific studies conducted mainly on older or ill people ( Kestenbaum et al., 2011 ).
Relatively few studies have focused on young, healthy, and physically