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Dive into the research topics where Piotr Ostaszewski is active.

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Featured researches published by Piotr Ostaszewski.


Nutrition | 2001

Creatine and β-hydroxy-β-methylbutyrate (HMB) additively increase lean body mass and muscle strength during a weight-training program

Ewa Jówko; Piotr Ostaszewski; Michał Jank; Jaroslaw Sacharuk; Agnieszka Zieniewicz; Jacek Wilczak; Steve Nissen

We investigated whether creatine (CR) and beta-hydroxy-beta-methylbutyrate (HMB) act by similar or different mechanisms to increase lean body mass (LBM) and strength in humans undergoing progressive resistance-exercise training. In this double-blind, 3-wk study, subjects (n = 40) were randomized to placebo (PL; n = 10), CR (20.0 g of CR/d for 7 d followed by 10.0 g of CR/d for 14 d; n = 11), HMB (3.0 g of HMB/d; n = 9), or CR-and-HMB (CR/HMB; n = 10) treatment groups. Over 3 wk, all subjects gained LBM, which was assessed by bioelectrical impedance analysis. The CR, HMB and CR/HMB groups gained 0.92, 0.39, and 1.54 kg of LBM, respectively, over the placebo group, with a significant effect with CR supplementation (main effect P = 0.05) and a trend with HMB supplementation (main effect P = 0.08). These effects were additive because there was no interaction between CR and HMB (CR x HMB main effect P = 0.73). Across all exercises, HMB, CR, and CR/HMB supplementation caused accumulative strength increases of 37.5, 39.1, and 51.9 kg, respectively, above the placebo group. The exercise-induced rise in serum creatine phosphokinase was markedly suppressed with HMB supplementation (main effect P = 0.01). However, CR supplementation antagonized the HMB effects on serum creatine phosphokinase (CR x HMB interactive effect P = 0.04). Urine urea nitrogen and plasma urea were not affected by CR supplementation, but both decreased with HMB supplementation (HMB effect P < 0.05), suggesting a nitrogen-sparing effect. In summary, CR and HMB can increase LBM and strength, and the effects are additive. Although not definitive, these results suggest that CR and HMB act by different mechanisms.


Nutrition Research | 2011

Green tea extract supplementation gives protection against exercise-induced oxidative damage in healthy men.

Ewa Jówko; Jaroslaw Sacharuk; Bożena Bałasińska; Piotr Ostaszewski; Małgorzata Charmas; Robert Charmas

The purpose of this study was to evaluate the effects of a long-term (4-week) green tea extract (GTE) supplementation in combination with strength training on selected blood markers of oxidative stress and muscular damage after a short-term exercise in previously untrained men. We hypothesized that GTE supplementation would elevate antioxidant potential and attenuate exercise-induced oxidative stress and muscular damage. Thirty-five male students were exposed to 4 weeks of strength training and received (in a randomized, double-blind design) GTE (n = 17; 640 mg polyphenols/d) or placebo (P; n = 18). Before (term I) and after 4 weeks of strength training and supplementation (term II), students performed a short-term muscular endurance test. Blood samples were collected at rest, 5 minutes after the muscular endurance test, and after 24 hours of recovery. Supplementation with GTE enhanced plasma total polyphenols at rest and 5 minutes after the muscular endurance test. Supplementation also contributed to the rise of resting total antioxidant status in plasma. Throughout the experiment (terms I and II), a reduction in plasma lipid hydroxyperoxides was observed 24 hours after the muscular endurance test. Four weeks of strength training resulted in an increase in plasma lipid hydroxyperoxides at rest, but only in the P group. In term I, the muscular endurance test induced an increase in activity of creatine kinase in plasma after 24 hours of recovery in both the P and GTE groups. In term II, plasma creatine kinase activity after 24 hours of recovery was elevated only in the P group. In conclusion, in previously untrained men, dietary supplementation with GTE (in combination with strength training) enhances the antioxidant defense system in plasma at rest and, in turn, may give protection against oxidative damage induced by both short-term muscular endurance test and long-term strength training.


Journal of Muscle Research and Cell Motility | 2003

Delineation of signalling pathway leading to antioxidant-dependent inhibition of dexamethasone-mediated muscle cell death.

Arkadiusz Orzechowski; Michał Jank; Barbara Gajkowska; Tomasz Sadkowski; Michał Marek Godlewski; Piotr Ostaszewski

The molecular mechanism of the cell death-promoting effect of dexamethasone (Dex) was studied during myogenesis (10 days) in L6 muscle cells by making use of several indices such as cell viability (protein synthesis, mitochondrial respiration), mortality (DNA fragmentation, chromatin condensation, structural modifications) and immunocytochemical studies [hydrogen peroxide, m-calpain (calpain 2)]. Dex initially (2 nM) stimulated protein synthesis (P < 0.001), but a further increase (20 nM) did not stimulate, whereas a higher dose (200 nM) inhibited formation of cellular proteins (P < 0.001). The latter, apparently, resulted from impaired cell viability (P < 0.001). From the day 4, structural changes featuring cell death were observed. Antioxidants [sodium ascorbate (ASC), catalase (CAT) or N-acetyl-L-cysteine (NAC)] as well as the inhibition of transcription and translation by actinomycin D abrogated Dex-induced cell death (P < 0.001). Using a fluorescent probe (DCFH-DA) we directly corroborated the working hypothesis of the mediating role of H2O2 in the reduction of cell viability by the excess of glucocorticoids. We also found that tPKC, PLCγ, PLA2 were required to induce Dex-dependent cell death since inactivation of tPKC by H7 completely abolished the cytotoxic effect of Dex, while the blockade of PLCγ and PLA2 by U 73122 partially abolished the effect. Cell death was triggered by Ca2+ influx necessary to activate m-calpain since it was reversed by the calcium chelator EGTA or m-calpain inhibitor ALLN but not EDTA nor ALLM. However, cell viability impaired by Ca2+ ionophore A 23187 (P < 0.001) was neither reversed by EGTA, nor EDTA, nor caspase-3 blocker – Ac DEVD CHO, nor ALLN, nor antioxidants – ASC, NAC, CAT. Specific caspase-3 inhibitor Ac DEVD CHO also did not rescue cells from Dex-induced cell death (P < 0.001), in contrast to m-calpain inhibitor – ALLN. Taken together, these findings suggest that reactive oxygen species inhibit protein synthesis and amplify m-calpain-dependent proteolysis. The events that led to the death of L6 muscle cells most likely resulted from Dex-mediated repression of antioxidative defences on the genomic level.


British Journal of Nutrition | 2016

Characterisation of equine satellite cell transcriptomic profile response to β-hydroxy-β-methylbutyrate (HMB).

Katarzyna A. Szcześniak; Anna Ciecierska; Piotr Ostaszewski; Tomasz Sadkowski

β-Hydroxy-β-methylbutyrate (HMB) is a popular ergogenic aid used by human athletes and as a supplement to sport horses, because of its ability to aid muscle recovery, improve performance and body composition. Recent findings suggest that HMB may stimulate satellite cells and affect expressions of genes regulating skeletal muscle cell growth. Despite the scientific data showing benefits of HMB supplementation in horses, no previous study has explained the mechanism of action of HMB in this species. The aim of this study was to reveal the molecular background of HMB action on equine skeletal muscle by investigating the transcriptomic profile changes induced by HMB in equine satellite cells in vitro. Upon isolation from the semitendinosus muscle, equine satellite cells were cultured until the 2nd day of differentiation. Differentiating cells were incubated with HMB for 24 h. Total cellular RNA was isolated, amplified, labelled and hybridised to microarray slides. Microarray data validation was performed with real-time quantitative PCR. HMB induced differential expressions of 361 genes. Functional analysis revealed that the main biological processes influenced by HMB in equine satellite cells were related to muscle organ development, protein metabolism, energy homoeostasis and lipid metabolism. In conclusion, this study demonstrated for the first time that HMB has the potential to influence equine satellite cells by controlling global gene expression. Genes and biological processes targeted by HMB in equine satellite cells may support HMB utility in improving growth and regeneration of equine skeletal muscle; however, the overall role of HMB in horses remains equivocal and requires further proteomic, biochemical and pharmacokinetic studies.


Reproduction Nutrition Development | 2002

Bioactive substances of plant origin in food - impact on genomics

Arkadiusz Orzechowski; Piotr Ostaszewski; Michał Jank; Sybilla Jacqueline Berwid


International Journal of Sport Nutrition and Exercise Metabolism | 2012

Effect of a single dose of green tea polyphenols on the blood markers of exercise-induced oxidative stress in soccer players.

Ewa Jówko; Jaroslaw Sacharuk; Bożena Bałasińska; Jacek Wilczak; Małgorzata Charmas; Piotr Ostaszewski; Robert Charmas


Research in Veterinary Science | 2011

Gender differences in exercise - induced intravascular haemolysis during race training in thoroughbred horses

Anna Cywińska; Ewa Szarska; Agnieszka Kowalska; Piotr Ostaszewski; Antoni Schollenberger


Polish Journal of Veterinary Sciences | 2000

Effect of 3-hydroxy-3-methylbutyrate [HMB] on muscle cathepsins and calpain activities during the post-dexamethasone recovery period in young rats

Michał Jank; Piotr Ostaszewski; S Rosochacki; J Wilczak; B Balasinska


Journal of Equine Veterinary Science | 2012

Effects of β-Hydroxy-β-Methylbutyrate and γ-Oryzanol on Blood Biochemical Markers in Exercising Thoroughbred Race Horses

Piotr Ostaszewski; Agnieszka Kowalska; Ewa Szarska; Piotr Szpotański; Anna Cywińska; Bożena Bałasińska; Tomasz Sadkowski


Genes and Nutrition | 2016

Transcriptomic profile adaptations following exposure of equine satellite cells to nutriactive phytochemical gamma-oryzanol

K. A. Szcześniak; Anna Ciecierska; Piotr Ostaszewski; Tomasz Sadkowski

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Michał Jank

Warsaw University of Life Sciences

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Tomasz Sadkowski

Warsaw University of Life Sciences

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Bożena Bałasińska

Warsaw University of Life Sciences

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Arkadiusz Orzechowski

Warsaw University of Life Sciences

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Ewa Jówko

Józef Piłsudski University of Physical Education in Warsaw

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Jaroslaw Sacharuk

Józef Piłsudski University of Physical Education in Warsaw

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Anna Ciecierska

Warsaw University of Life Sciences

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Anna Cywińska

Warsaw University of Life Sciences

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Małgorzata Charmas

Józef Piłsudski University of Physical Education in Warsaw

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Robert Charmas

Józef Piłsudski University of Physical Education in Warsaw

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