Analysis of human neutrophil phenotypes as biomarker to monitor exercise-induced immune changes

Abstract

The amplitude of the innate immune response reflects the degree of physiological stress imposed by exercise load. An optimal balance of exercise intensity and duration is essential for a balanced immune system and reduces the risk of dysfunction of the immune system. Therefore, it is hypothesized that neutrophils, as key players in the innate immune system, can be used as biomarker in detecting overtraining. The aim was to monitor the state of the innate immune system by phenotyping neutrophils during consecutive bouts of prolonged exercise. Study subjects were recruited from a cohort of walkers participating in a walking event on 3 consecutive days. Participants with immune deficiencies were excluded. Questionnaires to determine the physiological status of the participants were completed. Analysis of neutrophil receptor expression was done by a point-of-care fully automated flow cytometer. A total of 45 participants were recruited, of whom 39 participants were included for data analysis. Study participants had a median age of 64 (58-70) years. The absolute numbers CD16 dim /CD62L bright and CD16 bright /CD62L dim neutrophils were increased after the first 2 days of exercise followed by an adaptation/normalization after the third day. Participants with activated neutrophils (high CD11b expression) had an impaired physical feeling indicated by the participant on a lower visual analog scale compared to participants who did not have activated neutrophils (P = 0.017, P = 0.022). Consecutive days of prolonged exercise results in an initial systemic innate immune response, followed by normalization/adaptation. Increased neutrophil activation was associated with impaired physical feeling measured by a validated VAS score indicated by the participant. Fully automated point-of-care flow cytometry analysis of neutrophil phenotypes in a field laboratory might be a useful tool to monitor relevant differences in the systemic innate immune response in response to exercise. K E Y W O R D S innate immune system, neutrophil, prolonged walking, repetitive exercise 1 INTRODUCTION The immune system is very responsive to exercise, which leads to specific responses to acute and chronic exercise. 1-3 The amplitude of the Abbreviations: ANOVA, analysis of variance; BMI, body mass index; CD, cluster of differentiation; CR, complement receptor; DBP, diastolic blood pressure; HR, heart rate; IQR, interquartile range; MFI, median fluorescent intensity; SBP, systolic blood pressure; VAS, visual analog scale; WBC, white blood cell count. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Flow cytometric evaluation of the neutrophil compartment in COVID-19 at hospital presentation: A normal response to an abnormal situation

“…It could be that some of the data we have shown are affected by difference in age between the study groups. However, we have investigated similar neutrophil activation markers in previous studies and found no difference in baseline expression levels between ages 59 . Furthermore, we state that there is no neutrophil activation in COVID‐19 patients at presentation.…”

“…Because the healthy controls are relatively young compared to the patients included in this study, it is important to emphasize that the expression of nCD10/neprilysin on neutrophils measured by automated flow cytometry is not dependent on the age of the donor. 28,59 Expression of CD10/neprilysin is high as seen in neutrophils in healthy control blood (Fig. 7E and Marini et al 54 ).…”

“…However, we have investigated similar neutrophil activation markers in previous studies and found no difference in baseline expression levels between ages. 59 Furthermore, we state that there is no neutrophil activation in COVID-19 patients at presentation. This study entails neutrophil activation measured only in the peripheral blood with limited number of markers.…”

“…This indicates that CD10 is probably present in low amounts (on the surface and in storage pools) in blood neutrophils during COVID‐19 and other infectious diseases, possibly because of an altered or accelerated maturation process. Because the healthy controls are relatively young compared to the patients included in this study, it is important to emphasize that the expression of nCD10/neprilysin on neutrophils measured by automated flow cytometry is not dependent on the age of the donor 28,59 …”

Precision strength training: Data-driven artificial intelligence approach to strength and conditioning

“…Additionally, athletes have large inter-individual CK response dierences to the same exercise, further complicating the analysis of CK levels for recovery status [93]. Other biomarkers, which can be analysed for exercise recovery include transforming growth factor beta 1 (TGF-β1) [408], oxylipin [744], brain-derived neurotrophic factor (BNDF), oxygen reduction potential (ORP, redox potential) [647], cell-free DNA (cfDNA) [60], and neutrophil phenotypes [762].…”