Exercise Intensity Shapes Circulating CD34+ Progenitor-Cell Mobilization Despite Matched External Work: A Randomized Crossover Study
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 40
- 试验地点
- 1
- 主要终点
- Change From Baseline in Absolute Circulating Viable CD34+ Progenitor Cell Concentration
研究概览
简要总结
This randomized crossover study investigated whether exercise intensity influences the mobilization of circulating CD34+ progenitor cells when total external work is matched. Forty trained male endurance athletes completed two cycling exercise conditions in randomized order: a higher-intensity condition at 70% of peak work rate (WRpeak) and a lower-intensity condition at 30% WRpeak. Both conditions were performed until 250 kJ of external work had been completed and were separated by a washout period of at least 7 days. Venous blood samples were obtained before exercise, immediately after exercise, and at 15, 30, and 60 minutes of recovery. The primary outcome was the absolute concentration of viable circulating CD34+ cells measured using single-platform flow cytometry. Secondary outcomes included CD34+CD45dim, CD34+CD133+, and CD34+VEGFR2+ cell phenotypes, together with adrenergic, metabolic, chemokine, growth-factor, and cardiovascular responses. The study was designed to determine whether exercise intensity produces distinct progenitor-cell mobilization responses despite identical external work.
详细描述
Acute exercise can transiently alter the number of circulating hematopoietic and vascular-associated progenitor cells. However, exercise intensity and total exercise work are often changed simultaneously, making it difficult to determine whether mobilization is attributable specifically to exercise intensity or simply to a greater amount of external work.
This study used a randomized, counterbalanced, work-matched crossover design to isolate the effect of exercise intensity. Forty trained male endurance athletes completed two cycle-ergometer exercise conditions. In the higher-intensity condition, participants exercised at 70% of their individual peak work rate (WRpeak), whereas in the lower-intensity condition they exercised at 30% WRpeak. Both exercise bouts were terminated when exactly 250 kJ of external mechanical work had been completed. The two experimental sessions were separated by a washout period of at least 7 days.
Participants were assigned to one of two intervention sequences, with either the 70% WRpeak condition or the 30% WRpeak condition performed first. Venous blood samples were collected before exercise (baseline), immediately after exercise, and at 15, 30, and 60 minutes after exercise.
The primary outcome was the absolute concentration of viable circulating CD34+ progenitor cells, quantified by single-platform flow cytometry using counting beads. Additional cellular outcomes included CD34+CD45dim, CD34+CD133+, and CD34+VEGFR2+ phenotypes. Circulating epinephrine, norepinephrine, lactate, glucose, CXCL12/SDF-1, VEGF-A, and other prespecified biochemical markers were assessed alongside heart rate and blood pressure responses.
The principal objective was to compare the temporal pattern and magnitude of circulating CD34+ progenitor-cell mobilization between the two exercise-intensity conditions while holding external work constant. Secondary analyses examined whether differences in progenitor-cell mobilization were associated with exercise-induced adrenergic, metabolic, chemokine, growth-factor, and hemodynamic responses.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Basic Science
- 盲法
- Single (Outcomes Assessor)
盲法说明
assays were blinded to exercise condition and intervention sequence. Blood samples were labeled using coded identifiers that did not reveal participant identity, exercise intensity, or sequence assignment. Participants and exercise staff could not be blinded because of the obvious difference between the two exercise intensities.
入排标准
- 年龄范围
- 18 Years 至 35 Years（Adult）
- 性别
- Male
- 接受健康志愿者
- 是
入选标准
- •Eligible participants were healthy adult male endurance-trained athletes engaged in cycling and/or triathlon, within the prespecified age range, with a regular history of endurance training before enrollment. Participants were required to be medically fit to complete maximal exercise testing and both experimental cycling sessions, able to comply with the crossover design and washout requirements, and willing to provide written informed consent before participation.
排除标准
- •Participants were excluded if they had known cardiovascular, metabolic, hematological, inflammatory, or other medical conditions that could affect exercise responses or participant safety; an acute illness, infection, or musculoskeletal injury at the time of testing; use of medications or substances known to substantially influence cardiovascular, adrenergic, metabolic, or hematological responses; inability to complete the exercise-testing protocol or either experimental session; or failure to comply with the required pre-test or washout procedures.
研究组 & 干预措施
Sequence AB: 70% WRpeak Then 30% WRpeak
Participants first completed a cycling exercise bout at 70% of individual peak work rate (WRpeak) until 250 kJ of external work was achieved. After a washout period of at least 7 days, participants completed a second cycling bout at 30% WRpeak, also matched to 250 kJ of external work.
干预措施: Higher-Intensity Work-Matched Cycling Exercise (Behavioral)
Sequence AB: 70% WRpeak Then 30% WRpeak
Participants first completed a cycling exercise bout at 70% of individual peak work rate (WRpeak) until 250 kJ of external work was achieved. After a washout period of at least 7 days, participants completed a second cycling bout at 30% WRpeak, also matched to 250 kJ of external work.
干预措施: Lower-Intensity Work-Matched Cycling Exercise (Behavioral)
Sequence BA: 30% WRpeak Then 70% WRpeak
Participants first completed a cycling exercise bout at 30% of individual peak work rate (WRpeak) until 250 kJ of external work was achieved. After a washout period of at least 7 days, participants completed a second cycling bout at 70% WRpeak, also matched to 250 kJ of external work.
干预措施: Higher-Intensity Work-Matched Cycling Exercise (Behavioral)
Sequence BA: 30% WRpeak Then 70% WRpeak
Participants first completed a cycling exercise bout at 30% of individual peak work rate (WRpeak) until 250 kJ of external work was achieved. After a washout period of at least 7 days, participants completed a second cycling bout at 70% WRpeak, also matched to 250 kJ of external work.
干预措施: Lower-Intensity Work-Matched Cycling Exercise (Behavioral)
结局指标
主要结局
Change From Baseline in Absolute Circulating Viable CD34+ Progenitor Cell Concentration
时间窗: Baseline, immediately post-exercise, and 15, 30, and 60 minutes post-exercise during each intervention session.
Absolute circulating viable CD34+ progenitor cells were quantified in peripheral blood using single-platform flow cytometry with counting beads and expressed as cells/µL. Measurements were obtained before exercise and during recovery after each exercise condition. Change from baseline was calculated for each post-exercise time point and compared between the 70% WRpeak and 30% WRpeak work-matched exercise conditions.
次要结局
- Change From Baseline in Circulating CD34+CD45dim Progenitor Cell Concentration(Baseline, immediately post-exercise, and 15, 30, and 60 minutes post-exercise during each intervention session.)
- Change From Baseline in Circulating CD34+CD133+ Progenitor Cell Concentration(Baseline, immediately post-exercise, and 15, 30, and 60 minutes post-exercise during each intervention session.)
- Change From Baseline in Circulating CD34+VEGFR2+ Progenitor Cell Concentration(Baseline, immediately post-exercise, and 15, 30, and 60 minutes post-exercise during each intervention session.)
研究者
Saif Rasheed Ghanim
Assistant Professor
Samarra University