MiRNA126 - RGS16 - CXCL12 Cascade as a Potential Mechanism of Acute Exercise-Induced Precursor Cell Mobilization

Changes in hematopoietic stem cell numbers following acute exercise in non-athlete marathon runners

PURPOSE

Hematopoietic stem cell (HSC) transplant is one of the curative methods for some patients with hematological malignancies. Granulocyte colony-stimulating factor (G-CSF) is the most common drug used to mobilize CD34+ cells, generally found in small numbers. Recent evidence showed that exercise causes transient mobilization in HSC. However, the type and intensity of exercise have not been fully revealed. We aimed to detect a significant increase in stem cell levels following 60 ​min of running at a personalized running pace.

MATERIALS/METHODS

Eighteen runners, 48.2 ​± ​1.9 years with peak oxygen consumption of 46.2 ​± ​1.4 ​ml/kg/min, were enrolled in the study. The cardiopulmonary exercise test was performed to determine the individual running pace, and the participants ran 60-min on a treadmill at an intensity close to their ventilatory threshold (VT). The blood sampling for HSC count was performed before, immediately after, at the 1st, 4th and 24th hour after the 60-min running.

RESULTS

The CD34+ HSCs were 13.9 ​± ​2.3 ​cells/μl before and significantly increased immediately after to 19.5 ​± ​3.6 ​cells/μl (p ​< ​0.05). The consecutive HSC counts were 15.3 ​± ​2.2, 19.5 ​± ​4.8 and 15.1 ​± ​3.4 ​cells/μl at the 1st, 4th, and 24th hour, respectively.

CONCLUSION

The individual data showed that some runners had higher HSC levels than the transplantation limit before and after the 60-min running trail, which was maintained for 24 ​h. Pre-running high CD34+ HSCs may reflect an adaptive response to regular exercise, with a 60-min run near the VT further elevating HSCs. Individualized exercise may be a valuable tool to mobilize the CD34+ HSCs in peripheral blood for donors.

Brief cycling intervals incrementally increase the number of hematopoietic stem and progenitor cells in human peripheral blood

Introduction

Peripheral blood stem cell (PBSC) donation is the primary procedure used to collect hematopoietic stem and progenitor cells (HSPCs) for hematopoietic stem cell transplantation. Single bouts of exercise transiently enrich peripheral blood with HSPCs and cytolytic natural killer cells (CD56dim), which are important in preventing post-transplant complications. To provide a rationale to investigate the utility of exercise in a PBSC donation setting (≈3 h), this study aimed to establish whether interval cycling increased peripheral blood HSPC and CD56dim concentrations to a greater degree than continuous cycling.

Methods

In a randomised crossover study design, eleven males (mean ± SD: age 25 ± 7 years) undertook bouts of moderate intensity continuous exercise [MICE, 30 min, 65%-70% maximum heart rate (HRmax)], high-volume high intensity interval exercise (HV-HIIE, 4 × 4 min, 80%-85% HRmax) and low-volume HIIE (LV-HIIE, 4 × 2 min, 90%-95% HRmax). The cumulative impact of each interval on circulating HSPC (CD34+CD45dimSSClow) and CD56dim concentrations (cells/µL), and the bone marrow homing potential of HSPCs (expression of CXCR-4 and VLA-4) were determined.

Results

There was an increase in HSPC concentration after two intervals of LV-HIIE (Rest: 1.84 ± 1.55 vs. Interval 2: 2.94 ± 1.34, P = 0.01) and three intervals of HV-HIIE only (Rest: 2.05 ± 0.86 vs. Interval 3: 2.51 ± 1.05, P = 0.04). The concentration of all leukocyte subsets increased after each trial, with this greatest for CD56dim NK cells, and in HIIE vs. MICE (LV-HIIE: 4.77 ± 2.82, HV-HIIE: 4.65 ± 2.06, MICE: 2.44 ± 0.77, P < 0.0001). These patterns were observed for concentration, not frequency of CXCR-4+ and VLA-4+ HSPCs, which was unaltered. There was a marginal decrease in VLA-4, but not CXCR-4 expression on exercise-mobilised HSPCs after all trials (P < 0.0001).

Discussion

The results of the present study indicate that HIIE caused a more marked increase in HSPC and CD56dim NK cell concentrations than MICE, with mobilised HSPCs maintaining their bone marrow homing phenotype. LV-HIIE evoked an increase in HSPC concentration after just 2 × 2-minute intervals. The feasibility and clinical utility of interval cycling in a PBSC donation context should therefore be evaluated.

White adipose tissue-derived factors and prostate cancer progression: mechanisms and targets for interventions

Obesity represents an important risk factor for prostate cancer, driving more aggressive disease, chemoresistance, and increased mortality. White adipose tissue (WAT) overgrowth in obesity is central to the mechanisms that lead to these clinical observations. Adipose stromal cells (ASCs), the progenitors to mature adipocytes and other cell types in WAT, play a vital role in driving PCa aggressiveness. ASCs produce numerous factors, especially chemokines, including the chemokine CXCL12, which is involved in driving EMT and chemoresistance in PCa. A greater understanding of the impact of WAT in obesity-induced progression of PCa and the underlying mechanisms has begun to provide opportunities for developing interventional strategies for preventing or offsetting these critical events. These include weight loss regimens, therapeutic targeting of ASCs, use of calorie restriction mimetic compounds, and combinations of compounds as well as specific receptor targeting strategies.