Increased levels of circulating progenitor cells after 1-week sojourn at moderate altitude (Austrian Moderate Altitude Study II, AMAS II)

Theiß, Hans; Adam, Michaela; Greie, Sven; Schobersberger, Wolfgang; Humpeler, Egon; Franz, Wolfgang-M.

doi:10.1016/j.resp.2007.10.006

Cited by 13 publications

(6 citation statements)

References 31 publications

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“…This information would have added to the knowledge of exercise hormesis in trained participants, especially since recent studies did not find any significant exercise-induced CXCR-4 expression change on HPCs (Ross et al, 2018) or mature angiogenic T-cells (O'carroll et al, 2019) in active subjects. However, based on previous data from our own work (Kammerer et al, 2020), and others (Theiss et al, 2008), we would not expect any change in CXCR-4 mRNA expression in circulating MNCs or an increase in circulating CD34+/CXCR-4 cell number under acute exercise in normoxic conditions. Therefore, the focus of this study was solely on HPC clearance via transendothelial migration by CD31 expression on HPCs and not by the CXCR-4/CXCL-12 axis.…”

Section: Limitationsmentioning

confidence: 71%

Exercise-Induced Circulating Hematopoietic Stem and Progenitor Cells in Well-Trained Subjects

et al. 2020

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Section: Limitationsmentioning

confidence: 71%

Exercise-Induced Circulating Hematopoietic Stem and Progenitor Cells in Well-Trained Subjects

et al. 2020

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“…To our knowledge, so far few studies have addressed the effects of acute or subacute exposure to hypoxia on EPC homeostasis, yet reporting controversial results. In fact either a reduction (Mancuso et al 2008) or an increase (Theiss et al 2008) in EPCs was found after a 7–12 day sojourn at altitudes ranging from 1700 to 5000 m. By contrast, a 3 h intermittent hypobaric hypoxia exposure equivalent to 5000 m altitude for three consecutive days failed to change EPC concentration in four subjects (Viscor et al 2009), whereas a 1 h bout of normobaric hypoxia equivalent to 4850 m increased EPCs by approximately 70% (Ciulla et al 2007). These conflicting results may depend on a variety of factors, including degree and mode of hypoxia exposure, number and homogeneity of investigated subjects, concomitant physical activity, timing of blood sampling, time‐span before analysis, analytical procedures and inter‐individual variability of the measure.…”

Section: Discussionmentioning

confidence: 96%

Fast reduction of peripheral blood endothelial progenitor cells in healthy humans exposed to acute systemic hypoxia

Colombo

Marconi

Taddeo

et al. 2012

The Journal of Physiology

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Non-technical summary The endothelium is a thin layer of cells lining the interior surface of the entire circulatory system. Endothelial progenitor cells (EPCs) have a crucial role in maintaining the integrity of the endothelium, as they are recruited from the bone marrow to sites of endothelial injury where they contribute to blood vessel formation and repair. The factors regulating EPC mobilization and trafficking remain incompletely understood. We evaluated the time-course effects of a single 4 h bout of severe hypoxic breathing (simulating 4100 m altitude) followed by 4 h restoration in room air. We show that hypoxia alone induces a rapid disappearance of EPCs from blood, probably sustained by a prompt cell marginalization followed by a late increase in EPC apoptosis. These observations may broaden our understanding of the mechanisms operated by EPCs to maintain endothelial homeostasis and may help to elucidate the potential role of EPCs in regenerative medicine.Abstract There are hints that hypoxia exposure may affect the number of circulating endothelial progenitor cells (EPCs) in humans. To test this hypothesis, the concentration of EPCs was determined by flow cytometry in the peripheral blood of 10 young healthy adults before (0 h), at different times (0.5 h, 1 h, 2 h and 4 h) during a 4 h normobaric hypoxic breathing simulating 4100 m altitude, and in the following recovery breathing room air. Results were interpreted mainly on the basis of the changes in surface expression of CXC chemokine receptor-4 (CXCR-4, a chemokine receptor essential for EPC migration and homing) and the percentage of apoptotic cells, the plasmatic levels of markers of oxidative stress induced by hypoxic breathing. Compared to 0 h, the concentration of EPCs, identified as either CD45 dim /CD34 + /KDR + or CD45 dim /CD34 + /KDR + /CD133 + cells, decreased from 337 ± 83 ml −1 (mean ± SEM) to 223 ± 52 ml −1 (0.5 h; P < 0.005) and 100 ± 37 ml −1 (4 h; P < 0.005), and from 216 ± 91 to 161 ± 50 ml −1 (0.5 h; P < 0.05) and 45 ± 23 ml −1 (4 h; P < 0.005), respectively. Upon return to normoxia, their concentration increased slowly, and after 4 h was still lower than at 0 h (P < 0.05). During hypoxia, CXCR-4 expression and plasmatic stromal derived cell factor-1 (SDF-1) increased abruptly (0.5 h: +126% and +13%, respectively; P < 0.05), suggesting cell marginalization as a possible cause of the rapid hypoxia-induced EPC reduction. Moreover, hypoxia exposure induced an increase in EPC apoptosis and markers of oxidative stress, which was significantly evident only starting from 2 h and 4 h after hypoxia offset, respectively, suggesting that EPC apoptosis may contribute to the later phase of hypoxia-induced EPC reduction. Overall, these observations may provide new insights into the understanding of the mechanisms operated by EPCs to maintain endothelial homeostasis.

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“…Therefore, we measured different circulating CD34+ cell populations by FACS analysis (CD34+CD133+, CD34+ CD31+, CD34+CXCR-4+) and selected cytokines in our AMAS II volunteers before and on day 6 of vacation at 1,700 m. For methodological details, see Ref. [18]. The numbers of CD34+CXCR-4+ cells were significantly increased in the peripheral blood after the end of vacation.…”

Section: Amas Ii-circulation Of Adult Progenitor Cellsmentioning

confidence: 99%

Austrian Moderate Altitude Studies (AMAS): benefits of exposure to moderate altitudes (1,500–2,500 m)

et al. 2009

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Increased levels of circulating progenitor cells after 1-week sojourn at moderate altitude (Austrian Moderate Altitude Study II, AMAS II)

Cited by 13 publications

References 31 publications

Exercise-Induced Circulating Hematopoietic Stem and Progenitor Cells in Well-Trained Subjects

Exercise-Induced Circulating Hematopoietic Stem and Progenitor Cells in Well-Trained Subjects

Fast reduction of peripheral blood endothelial progenitor cells in healthy humans exposed to acute systemic hypoxia

Austrian Moderate Altitude Studies (AMAS): benefits of exposure to moderate altitudes (1,500–2,500 m)

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