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| 2. |
- Cardinale, Daniele A., 1982-, et al.
(författare)
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Influence of Hyperoxic-Supplemented High-Intensity Interval Training on Hemotological and Muscle Mitochondrial Adaptations in Trained Cyclists.
- 2019
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Ingår i: Frontiers in Physiology. - : Frontiers Media S.A.. - 1664-042X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Background: Hyperoxia (HYPER) increases O2 carrying capacity resulting in a higher O2 delivery to the working muscles during exercise. Several lines of evidence indicate that lactate metabolism, power output, and endurance are improved by HYPER compared to normoxia (NORM). Since HYPER enables a higher exercise power output compared to NORM and considering the O2 delivery limitation at exercise intensities near to maximum, we hypothesized that hyperoxic-supplemented high-intensity interval training (HIIT) would upregulate muscle mitochondrial oxidative capacity and enhance endurance cycling performance compared to training in normoxia. Methods: 23 trained cyclists, age 35.3 ± 6.4 years, body mass 75.2 ± 9.6 kg, height 179.8 ± 7.9 m, and VO2max 4.5 ± 0.7 L min-1 performed 6 weeks polarized and periodized endurance training on a cycle ergometer consisting of supervised HIIT sessions 3 days/week and additional low-intensity training 2 days/week. Participants were randomly assigned to either HYPER (FIO2 0.30; n = 12) or NORM (FIO2 0.21; n = 11) breathing condition during HIIT. Mitochondrial respiration in permeabilized fibers and isolated mitochondria together with maximal and submaximal VO2, hematological parameters, and self-paced endurance cycling performance were tested pre- and posttraining intervention. Results: Hyperoxic training led to a small, non-significant change in performance compared to normoxic training (HYPER 6.0 ± 3.7%, NORM 2.4 ± 5.0%; p = 0.073, ES = 0.32). This small, beneficial effect on the self-paced endurance cycling performance was not explained by the change in VO2max (HYPER 1.1 ± 3.8%, NORM 0.0 ± 3.7%; p = 0.55, ES = 0.08), blood volume and hemoglobin mass, mitochondrial oxidative phosphorylation capacity (permeabilized fibers: HYPER 27.3 ± 46.0%, NORM 16.5 ± 49.1%; p = 0.37, ES = 3.24 and in isolated mitochondria: HYPER 26.1 ± 80.1%, NORM 15.9 ± 73.3%; p = 0.66, ES = 0.51), or markers of mitochondrial content which were similar between groups post intervention. Conclusions: This study showed that 6 weeks hyperoxic-supplemented HIIT led to marginal gain in cycle performance in already trained cyclists without change in VO2max, blood volume, hemoglobin mass, mitochondrial oxidative phosphorylation capacity, or exercise efficiency. The underlying mechanisms for the potentially meaningful performance effects of hyperoxia training remain unexplained and may raise ethical questions for elite sport.
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- Cardinale, Daniele A., 1982-, et al.
(författare)
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Muscle mass and inspired oxygen influence oxygen extraction at maximal exercise : role of mitochondrial oxygen affinity.
- 2019
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Ingår i: Acta Physiologica. - : Wiley-Blackwell. - 1748-1708 .- 1748-1716. ; 225:1
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Tidskriftsartikel (refereegranskat)abstract
- AIM:We examined the Fick components together with mitochondrial O2 affinity (p50mito ) in defining O2 extraction and O2 uptake during exercise with large and small muscle mass during normoxia (NORM) and hyperoxia (HYPER).METHODS:Seven individuals performed two incremental exercise tests to exhaustion on a bicycle ergometer (BIKE) and two on a one-legged knee extension ergometer (KE) in NORM or HYPER. Leg blood flow and VO2 were determined by thermodilution and the Fick method. Maximal ADP-stimulated mitochondrial respiration (OXPHOS) and p50mito were measured ex vivo in isolated mitochondria. Mitochondrial excess capacity in the leg was determined from OXPHOS in permeabilized fibers and muscle mass measured with magnetic resonance imaging in relation to peak leg O2 delivery.RESULTS:The ex vivo p50mito increased from 0.06±0.02 to 0.17±0.04 kPa with varying substrate supply and O2 flux rates from 9.84±2.91 to 16.34±4.07 pmol O2 ·s-1 ·μg-1 respectively. O2 extraction decreased from 83% in BIKE to 67% in KE as a function of a higher O2 delivery, and lower mitochondrial excess capacity. There was a significant relationship between O2 extraction and mitochondrial excess capacity and p50mito that was unrelated to blood flow and mean transit time.CONCLUSION:O2 extraction varies with mitochondrial respiration rate, p50mito and O2 delivery. Mitochondrial excess capacity maintains a low p50mito which enhances O2 diffusion from microvessels to mitochondria during exercise. This article is protected by copyright. All rights reserved.
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| 4. |
- Cardinale, Daniele A., 1982-, et al.
(författare)
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Superior Intrinsic Mitochondrial Respiration in Women Than in Men.
- 2018
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Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Sexual dimorphism is apparent in humans, however, to date no studies have investigated mitochondrial function focusing on intrinsic mitochondrial respiration (i.e., mitochondrial respiration for a given amount of mitochondrial protein) and mitochondrial oxygen affinity (p50mito) in relation to biological sex in human. A skeletal muscle biopsy was donated by nine active women, and ten men matched for maximal oxygen consumption (VO2max) and by nine endurance trained men. Intrinsic mitochondrial respiration, assessed in isolated mitochondria, was higher in women compared to men when activating complex I (CIP) and complex I+II (CI+IIP) (p < 0.05), and was similar to trained men (CIP, p = 0.053; CI+IIP, p = 0.066). Proton leak and p50mito were higher in women compared to men independent of VO2max. In conclusion, significant novel differences in mitochondrial oxidative function, intrinsic mitochondrial respiration and p50mito exist between women and men. These findings may represent an adaptation in the oxygen cascade in women to optimize muscle oxygen uptake to compensate for a lower oxygen delivery during exercise.
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| 5. |
- Cardinale, Daniele, 1982-, et al.
(författare)
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Is the Ekblom-Bak Test a valid screening tool for Vo2peak in highly active individuals?
- 2015
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Konferensbidrag (refereegranskat)abstract
- IntroductionMaximal oxygen consumption testing is suggested to be regularly included between training blocks of athletes in order to monitor changes in fitness throughout the season. However, despite the good reliability and validity of this physiological test, an expensive metabolic chart, and expert personnel are needed. Further, the maximal effort needed by the athlete makes this test difficult to be performed routinely. Therefore, it is important to develop valid tools that are also feasible for the estimation of the maximal oxygen consumption. The aim of this study was to validate the Ekblom-Bak test (EBT) (Ekblom-Bak et al., 2014) against an incremental test measuring peak VO2 by gas exchange on a cycle ergometer in well-trained individuals.Methods33 highly active individuals aged 34.5±6.6yrs (mean ± standard deviation (SD)) body mass 74.5±12kg, and height; 178± 9.3m) participated in the study. The EBT test was performed prior to the incremental exercise test to peak effort on a cycle ergometer for VO2peak assessment. Oxygen uptake was determined by an automated measuring system for oxygen uptake with a mixing chamber (OxygenPro, Jaeger GmbH, Germany) validated against the Douglas bag method resulting in a typical error of 2%. The mean difference and standard deviation of the differences between the EBT and measured VO2peak was calculated with Bland-Altman analysis.ResultsThe measured mean and SD VO2peak was 4.1±0.8 L•min-1 for the whole group (male 4.4±0.6 L•min-1 and female 2.9±0.5 L•min-1). The mean differences between measured and estimated (EBT) VO2peak was 0.05 L•min-1 (95% CI; -0.15 to 0.25). CV was 13.2% in the whole group with no significant differences between sexes. For individuals with a VO2peak within the valid range of the EBT (VO2max 1.56 to 4.49 L•min-1, n=23), the mean differences between measured and estimate VO2peak was -0.22 L•min-1 (95% CI; -0.36 to -0.08), resulting in a CV of 8.2%. For individuals above the valid limit (n=10), the mean difference was 0.68L•min-1(95% CI; 0.47 to 0.98) with a CV of 6.9%. Discussion The Ekblom-Bak test is an easily applied and inexpensive screening tool for a population of highly active individuals within the current validity range, and may be used routinely in monitoring fitness.ReferencesEkblom-Bak E, Björkman F, Hellenius ML, Ekblom B (2014). Scand J Med Sci Sports, 24(2), 319-326
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| 6. |
- Ekblom, Robert
(författare)
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A bird's eye view of a deleterious recessive allele
- 2016
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 85:4, s. 855-856
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Tidskriftsartikel (refereegranskat)abstract
- In Focus: Trask, A.E., Bignal, E.M., McCracken, D.I., Monaghan, P., Piertney, S.B. & Reid, J.M. (2016) Evidence of the phenotypic expression of a lethal recessive allele under inbreeding in a wild population of conservation concern. Journal of Animal Ecology, 85, 879-891. In this issue of Journal of Animal Ecology, Trask etal. () report on a strange, lethal, blindness that regularly affects chicks of an endangered bird population. The authors show that the inheritance mode of this blindness disease precisely matches the expectations of a recessive deleterious mutation. Intriguingly, there is also an indication that the disease-causing variant might be maintained in the population by balancing selection, due to a selective advantage for heterozygotes. Could this finding have consequences for conservation actions implemented for the population?
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| 7. |
- Ekblom, Robert, Docent, 1976-, et al.
(författare)
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Development of transcriptome genetic markers for the great snipe (Gallinago media)
- 2017
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Ingår i: Conservation Genetics Resources. - : SPRINGER. - 1877-7252 .- 1877-7260. ; 9:4, s. 643-645
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Tidskriftsartikel (refereegranskat)abstract
- We sequenced the transcriptomes of 14 great snipe (Gallinago media) males from the Gavalia study population (central Norway) using Roche 454 technology. The assembled transcriptome sequences (RNA-Seq) was used to identify 140 microsatellite repeat sequences with sufficient flanking sequence information for primer design. In addition several 1000 single nucleotide polymorphisms in the transcriptome were identified, and a small subset of these were verified by independent genotyping.
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| 9. |
- Ekblom, Robert, Docent, 1976-, et al.
(författare)
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Genome sequencing and conservation genomics in the Scandinavian wolverine population
- 2018
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Ingår i: Conservation Biology. - : WILEY. - 0888-8892 .- 1523-1739. ; 32:6, s. 1301-1312
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Tidskriftsartikel (refereegranskat)abstract
- Genetic approaches have proved valuable to the study and conservation of endangered populations, especially for monitoring programs, and there is potential for further developments in this direction by extending analyses to the genomic level. We assembled the genome of the wolverine (Gulo gulo), a mustelid that in Scandinavia has recently recovered from a significant population decline, and obtained a 2.42 Gb draft sequence representing >85% of the genome and including >21,000 protein-coding genes. We then performed whole-genome resequencing of 10 Scandinavian wolverines for population genomic and demographic analyses. Genetic diversity was among the lowest detected in a red-listed population (mean genome-wide nucleotide diversity of 0.05%). Results of the demographic analyses indicated a long-term decline of the effective population size (N-e) from 10,000 well before the last glaciation to N-e appeared even lower. The genome-wide F-IS level was 0.089 (possibly signaling inbreeding), but this effect was not observed when analyzing a set of highly variable SNP markers, illustrating that such markers can give a biased picture of the overall character of genetic diversity. We found significant population structure, which has implications for population connectivity and conservation. We used an integrated microfluidic circuit chip technology to develop an SNP-array consisting of 96 highly informative markers that, together with a multiplex pre-amplification step, was successfully applied to low-quality DNA from scat samples. Our findings will inform management, conservation, and genetic monitoring of wolverines and serve as a genomic roadmap that can be applied to other endangered species. The approach used here can be generally utilized in other systems, but we acknowledge the trade-off between investing in genomic resources and direct conservation actions.
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