Publications by authors named "Leo Koenderman"

150 Publications

Cytokine receptor clustering in sensory neurons with an engineered cytokine fusion protein triggers unique pain resolution pathways.

Proc Natl Acad Sci U S A 2021 Mar;118(11)

Center for Translational Immunology, University Medical Center Utrecht, Utrecht University, 3584 EA Utrecht, The Netherlands;

New therapeutic approaches to resolve persistent pain are highly needed. We tested the hypothesis that manipulation of cytokine receptors on sensory neurons by clustering regulatory cytokine receptor pairs with a fusion protein of interleukin (IL)-4 and IL-10 (IL4-10 FP) would redirect signaling pathways to optimally boost pain-resolution pathways. We demonstrate that a population of mouse sensory neurons express both receptors for the regulatory cytokines IL-4 and IL-10. This population increases during persistent inflammatory pain. Triggering these receptors with IL4-10 FP has unheralded biological effects, because it resolves inflammatory pain in both male and female mice. Knockdown of both IL4 and IL10 receptors in sensory neurons in vivo ablated the IL4-10 FP-mediated inhibition of inflammatory pain. Knockdown of either one of the receptors prevented the analgesic gain-of-function of IL4-10 FP. In vitro, IL4-10 FP inhibited inflammatory mediator-induced neuronal sensitization more effectively than the combination of cytokines, confirming its superior activity. The IL4-10 FP, contrary to the combination of IL-4 and IL-10, promoted clustering of IL-4 and IL-10 receptors in sensory neurons, leading to unique signaling, that is exemplified by activation of shifts in the cellular kinome and transcriptome. Interrogation of the potentially involved signal pathways led us to identify JAK1 as a key downstream signaling element that mediates the superior analgesic effects of IL4-10 FP. Thus, IL4-10 FP constitutes an immune-biologic that clusters regulatory cytokine receptors in sensory neurons to transduce unique signaling pathways required for full resolution of persistent inflammatory pain.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.2009647118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7980471PMC
March 2021

Refractory neutrophils and monocytes in patients with inflammatory bowel disease after repeated bouts of prolonged exercise.

Cytometry B Clin Cytom 2021 Mar 8. Epub 2021 Mar 8.

Center for Translational Immunology (CTI), University Medical Center Utrecht, Utrecht, CX, The Netherlands.

Background: Neutrophils and monocytes are key immune effector cells in inflammatory bowel disease (IBD) that is associated with chronic inflammation in the gut. Patients with stable IBD who perform exercise have significantly fewer flare-ups of the disease, but no underlying mechanism has been identified. Therefore, the aim of this study was to compare the responsiveness/refractoriness of these innate immune cells after repeated bouts of prolonged exercise in IBD patients and controls.

Methods: Patients with IBD and age- and gender-matched healthy controls were recruited from a cohort of walkers participating in a 4-day walking event. Blood analysis was performed at baseline and after 3 days of walking. Responsiveness to the bacterial/mitochondrial-stimulus N-Formylmethionine-leucyl-phenylalanine (fMLF) was tested in granulocytes and monocytes by measuring the expression of activation markers after adding this stimulus to whole blood.

Results: In total 38 participants (54 ± 12 years) were included in this study: 19 walkers with and 19 walkers without IBD. After 3 days of prolonged exercise, a significant increase in responsiveness to fMLF was observed in all participants irrespective of disease. However, IBD patients showed significantly less responsiveness in neutrophils and monocytes, compared with non-IBD walkers.

Conclusions: Increased responsiveness of neutrophils and monocyte to fMLF was demonstrated after repetitive bouts of prolonged exercise. Interestingly, this exercise was associated with relative refractoriness of both neutrophils and monocytes in IBD patients. These refractory cells might create a lower inflammatory state in the intestine providing a putative mechanism for the decrease in flare-ups in IBD patients after repeated exercise.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cyto.b.21996DOI Listing
March 2021

Preoperative Cerebrospinal Fluid Cortisol and the Risk of Postoperative Delirium: A Prospective Study of Older Hip Fracture Patients.

Dement Geriatr Cogn Disord 2020 2;49(6):604-610. Epub 2021 Mar 2.

Department of Neurology, University Medical Center, Amsterdam, The Netherlands.

Background: Ageing, depression, and neurodegenerative disease are common risk factors for delirium in the elderly. These risk factors are associated with dysregulation of the hypothalamic-pituitary-adrenal axis, resulting in higher levels of cortisol under normal and stressed conditions and a slower return to baseline.

Objectives: We investigated whether elevated preoperative cerebrospinal fluid (CSF) cortisol levels are associated with the onset of postoperative delirium.

Methods: In a prospective cohort study CSF samples were collected after cannulation for the introduction of spinal anesthesia of 75 patients aged 75 years and older admitted for surgical repair of acute hip fracture. Delirium was assessed with the confusion assessment method (CAM) and the Delirium Rating Scale-Revised-98 (DRS-R98). Because the CAM and DRS-R98 were available for time of admission and 5 postoperative days, we used generalized estimating equations and linear mixed modeling to examine the association between preoperative CSF cortisol levels and the onset of postoperative delirium.

Results: Mean age was 83.5 (SD 5.06) years, and prefracture cognitive decline was present in one-third of the patients (24 [33%]). Postoperative delirium developed in 27 (36%) patients. We found no association between preoperative CSF cortisol levels and onset or severity of postoperative delirium.

Conclusions: These findings do not support the hypothesis that higher preoperative CSF cortisol levels are associated with the onset of postoperative delirium in elderly hip fracture patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1159/000512984DOI Listing
March 2021

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

J Leukoc Biol 2021 01;109(1):99-114

Department of Respiratory Medicine, University Medical Center Utrecht, Heidelberglaan, Utrecht, The Netherlands.

Coronavirus disease 2019 (COVID-19) is a rapidly emerging pandemic disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Critical COVID-19 is thought to be associated with a hyper-inflammatory process that can develop into acute respiratory distress syndrome, a critical disease normally mediated by dysfunctional neutrophils. This study tested the hypothesis whether the neutrophil compartment displays characteristics of hyperinflammation in COVID-19 patients. Therefore, a prospective study was performed on all patients with suspected COVID-19 presenting at the emergency room of a large academic hospital. Blood drawn within 2 d after hospital presentation was analyzed by point-of-care automated flow cytometry and compared with blood samples collected at later time points. COVID-19 patients did not exhibit neutrophilia or eosinopenia. Unexpectedly neutrophil activation markers (CD11b, CD16, CD10, and CD62L) did not differ between COVID-19-positive patients and COVID-19-negative patients diagnosed with other bacterial/viral infections, or between COVID-19 severity groups. In all patients, a decrease was found in the neutrophil maturation markers indicating an inflammation-induced left shift of the neutrophil compartment. In COVID-19 this was associated with disease severity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/JLB.5COVA0820-520RRRDOI Listing
January 2021

An increase in CD62L neutrophils precedes the development of pulmonary embolisms in COVID-19 patients.

Scand J Immunol 2021 Jan 22:e13023. Epub 2021 Jan 22.

Department of Respiratory Medicine, University Medical Center Utrecht, Utrecht, The Netherlands.

Objectives: A high incidence of pulmonary embolism (PE) is reported in patients with critical coronavirus disease 2019 (COVID-19). Neutrophils may contribute to this through a process referred to as immunothrombosis. The aim of this study was to investigate the occurrence of neutrophil subpopulations in blood preceding the development of COVID-19 associated PE.

Methods: We studied COVID-19 patients admitted to the ICU of our tertiary hospital between 19-03-2020 and 17-05-2020. Point-of-care fully automated flow cytometry was performed prior to ICU admission, measuring the neutrophil activation/maturation markers CD10, CD11b, CD16 and CD62L. Neutrophil receptor expression was compared between patients who did or did not develop PE (as diagnosed on CT angiography) during or after their ICU stay.

Results: Among 25 eligible ICU patients, 22 subjects were included for analysis, of whom nine developed PE. The median (IQR) time between neutrophil phenotyping and PE occurrence was 9 (7-12) days. A significant increase in the immune-suppressive neutrophil phenotype CD16 /CD62L was observed on the day of ICU admission (P = 0.014) in patients developing PE compared to patients who did not.

Conclusion: The increase in this neutrophil phenotype indicates that the increased number of CD16 /CD62L neutrophils might be used as prognostic marker to predict those patients that will develop PE in critical COVID-19 patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/sji.13023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7995011PMC
January 2021

Monitoring eosinophils to guide therapy with biologics in asthma: does the compartment matter?

Allergy 2021 Apr 31;76(4):1294-1297. Epub 2020 Dec 31.

Department of Medicine, Division of Respirology, McMaster University and St Joseph's Healthcare, Hamilton, ON, Canada.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/all.14700DOI Listing
April 2021

Instant intra-operative neutropenia despite the emergence of banded (CD16/CD62L) neutrophils in peripheral blood - An observational study during extensive trauma-surgery in pigs.

Injury 2021 Mar 6;52(3):426-433. Epub 2020 Nov 6.

University Medical Centre Utrecht, Department of Trauma, Heidelberglaan 100, 3584 Utrecht, the Netherlands. Electronic address:

Introduction: Deregulation of polymorphonuclear neutrophils (PMNs) is an essential step in the development of inflammatory complications upon trauma. Different neutrophil subtypes have been identified recently, however, the role of neutrophil subtypes in immunoregulation upon trauma is unclear. We hypothesize that extensive trauma surgery causes instant progressive heterogeneity of the blood neutrophil pool, and increased appearance of young (CD16/CD62L) neutrophils in peripheral blood.

Material And Methods: A standardized extensive thoraco-abdominal porcine trauma surgery model was utilized, and 12 animals were included. Blood was collected at defined timepoints and neutrophil numbers and subtypes were studied by flowcytometry. Neutrophil subtypes were identified by differences in cell surface expression levels of CD16 (FcγRIII) and CD62L (L-selectin). Porcine neutrophil subtypes were further characterized after flow sorting.

Results: Eleven animals survived the 3-hour surgical protocol. Neutrophil numbers dropped significantly from a mean of 8,6 ± 3,5 × 10 to 2,4 ± 1,8 × 10 cells/ml during 180 min, (p<0.001). Simultaneously, the blood PMN population became increasingly heterogeneous due to the appearance of new neutrophil subtypes. Cell sorting experiments and cytological analysis revealed that these porcine subtypes had specific morphological characteristics, mimicking their human counterparts. At baseline, 88% ± 1 percent of circulatory PMNs comprised of mature (CD16/CD62L) PMNs, while at 3 h the blood PMN pool consisted of 59% ± 2 percent of mature subtypes (p<0.001). Despite a marked drop in neutrophil levels during surgery, absolute and relative numbers of banded (CD16/CD62L) neutrophils continued to rise throughout surgery.

Conclusion: Standardized extensive trauma surgery was associated with instant progressive neutropenia and increased heterogeneity of the blood neutrophil pool. Furthermore, three different neutrophil subsets in peripheral porcine blood were identified over the course of surgery. Further studies should clarify their precise role in the development of early organ failure upon extensive trauma surgery. This for the first time exemplifies experimentally the time constraints and impact of damage control surgery after severe trauma.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.injury.2020.11.018DOI Listing
March 2021

Eosinophilic inflammation in COPD: from an inflammatory marker to a treatable trait.

Thorax 2020 Oct 29. Epub 2020 Oct 29.

Institute of Cellular Medicine, NIHR Biomedical Research Centre for Aging and Department of Respiratory Medicine, Newcastle upon Tyne NHS Foundation Trust, Newcastle upon Tyne, UK

The heterogeneity of chronic obstructive pulmonary disease (COPD) creates many diagnostic, prognostic, treatment and management challenges, as the pathogenesis of COPD is highly complex and the underlying cellular and molecular mechanisms remain poorly understood. A reliable, easy-to-measure, clinically relevant biomarker would be invaluable for improving outcomes for patients. International and national guidance for COPD suggests using blood eosinophil counts as a biomarker to help estimate likely responsiveness to inhaled corticosteroids (ICS) and, potentially, to aid effective management strategies. However, with the mechanism underlying the association between higher eosinophil levels and ICS effect unknown, use of the blood eosinophil count in COPD continues to be widely debated by the respiratory community.Two international meetings involving respiratory medicine specialists, immunologists and primary and secondary care clinicians were held in November 2018 and March 2019, facilitated and funded by GlaxoSmithKline plc. The aims of these meetings were to explore the role of eosinophils in the disease processes of COPD and as prognostic and diagnostic markers, and to identify areas of deficient knowledge that warrant further research. The consensus views of the attendees on key topics, contextualised with current literature, are summarised in this review article, with the aim of aiding ongoing research into the disease processes of COPD and the development of biomarkers to aid clinical management.Under certain conditions, eosinophils can be recruited to the lung, and increasing evidence supports a role for eosinophilic inflammation in some patients with COPD. Infiltration of eosinophils across the bronchial vascular epithelium into the airways is promoted by the actions of immunoregulatory cells, cytokines and chemokines, where eosinophil-mediated inflammation is driven by the release of proinflammatory mediators.Multiple studies and two meta-analyses suggest peripheral blood eosinophils may correlate positively with an increased likelihood of exacerbation reduction benefits of ICS in COPD. The studies, however, vary in design and duration and by which eosinophil levels are viewed as predictive of an ICS response. Generally, the response was seen when eosinophil levels were 100-300 cells/µL (or higher), levels which are traditionally viewed within the normal range. Some success with interleukin-5-targeted therapy suggests that the eosinophilic phenotype may be a treatable trait.The use of biomarkers could help to stratify treatment for COPD-the goal of which is to improve patient outcomes. Some evidence supports eosinophils as a potential biomarker of a treatable trait in COPD, though it is still lacking and research is ongoing. A unified consensus and a practical, accessible and affordable method of utilising any biomarker for COPD was thought to be of most importance. Challenges around its utilisation may include presenting a clear and pragmatic rationale for biomarker-driven therapy, guidance on ICS withdrawal between primary and secondary care and a lack of financial incentives supporting broad application in clinical practice. Future treatments should, perhaps, be more targeted rather than assuming the primary disease label (COPD or asthma) will define treatment response.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/thoraxjnl-2020-215167DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7815887PMC
October 2020

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

J Leukoc Biol 2021 Apr 6;109(4):833-842. Epub 2020 Sep 6.

Center for Translational Immunology (CTI), University Medical Center Utrecht, Utrecht, The Netherlands.

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 /CD62L and CD16 /CD62L 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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/JLB.5A0820-436RDOI Listing
April 2021

Point-of-Care Analysis of Neutrophil Phenotypes: A First Step Toward Immuno-Based Precision Medicine in the Trauma ICU.

Crit Care Explor 2020 Jul 17;2(7):e0158. Epub 2020 Jul 17.

Department of Trauma Surgery, University Medical Center Utrecht, Utrecht, The Netherlands.

Objectives: The amount of tissue damage and the amplitude of the immune response after trauma are related to the development of infectious complications later on. Changes in the neutrophil compartment can be used as read out of the amplitude of the immune response after trauma. The study aim was to test whether 24/7 point-of-care analysis of neutrophil marker expression by automated flow cytometry can be achieved after trauma.

Design: A prospective cohort study was performed. Polytrauma patients who developed infectious complications were compared with polytrauma patients who did not develop infectious complications.

Setting: The study was performed in a level 1 trauma center.

Patients: All trauma patients presented in the trauma bay were included.

Interventions: An extra blood tube was drawn from all patients. Thereafter, a member of the trauma team placed the blood tube in the fully automated flow cytometer, which was located in the corner of the trauma room. Next, a modified and tailored protocol for this study was automatically performed.

Main Results: The trauma team was able to successfully start the point-of-care automated flow cytometry analysis in 156 of 164 patients, resulting in a 95% success rate. Polytrauma patients who developed infectious complications had a significantly higher %CD16/CD62L neutrophils compared with polytrauma patients who did not develop infectious complications ( = 0.002). Area under the curve value for %CD16/CD62L neutrophils is 0.90 (0.83-0.97).

Conclusions: This study showed the feasibility of the implementation of a fully automated point-of-care flow cytometry system for the characterization of the cellular innate immune response in trauma patients. This study supports the concept that the assessment of CD16/CD62L neutrophils can be used for early detection of patients at risk for infectious complications. Furthermore, this can be used as first step toward immuno-based precision medicine of polytrauma patients at the ICU.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/CCE.0000000000000158DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7371075PMC
July 2020

Fragile neutrophils in surgical patients: A phenomenon associated with critical illness.

PLoS One 2020 4;15(8):e0236596. Epub 2020 Aug 4.

Department of trauma surgery, University Medical Center Utrecht, Utrecht, the Netherlands.

Leukocyte viability (determined by e.g. propidium iodide [PI] staining) is automatically measured by hematology analyzers to check for delayed bench time. Incidental findings in fresh blood samples revealed the existence of leukocytes with decreased viability in critically ill surgical patients. Not much is known about these cells and their functional and/or clinical implications. Therefore, we investigated the incidence of decreased leukocyte viability, the implications for leukocyte functioning and its relation with clinical outcomes. An automated alarm was set in a routine hematology analyzer (Cell-Dyn Sapphire) for the presence of non-viable leukocytes characterized by increased fluorescence in the PI-channel (FL3:630±30nm). Patients with non-viable leukocytes were prospectively included and blood samples were drawn to investigate leukocyte viability in detail and to investigate leukocyte functioning (phagocytosis and responsiveness to a bacterial stimulus). Then, a retrospective analysis was conducted to investigate the incidence of fragile neutrophils in the circulation and clinical outcomes of surgical patients with fragile neutrophils hospitalized between 2013-2017. A high FL3 signal was either caused by 1) neutrophil autofluorescence which was considered false positive, or by 2) actual non-viable PI-positive neutrophils in the blood sample. These two causes could be distinguished using automatically generated data from the hematology analyzer. The non-viable (PI-positive) neutrophils proved to be viable (PI-negative) in non-lysed blood samples, and were therefore referred to as 'fragile neutrophils'. Overall leukocyte functioning was not impaired in patients with fragile neutrophils. Of the 11 872 retrospectively included surgical patients, 75 (0.63%) were identified to have fragile neutrophils during hospitalization. Of all patients with fragile neutrophils, 75.7% developed an infection, 70.3% were admitted to the ICU and 31.3% died during hospitalization. In conclusion, fragile neutrophils occur in the circulation of critically ill surgical patients. These cells can be automatically detected during routine blood analyses and are an indicator of critical illness.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0236596PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7402494PMC
October 2020

Recognizing the mobilization of neutrophils with banded nuclei early after trauma.

Int J Lab Hematol 2020 10 6;42(5):e224-e227. Epub 2020 Jul 6.

Department of Trauma Surgery, University Medical Center Utrecht, Utrecht, The Netherlands.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/ijlh.13272DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7586805PMC
October 2020

Multi-set Pre-processing of Multicolor Flow Cytometry Data.

Sci Rep 2020 06 16;10(1):9716. Epub 2020 Jun 16.

Radboud University, Institute for Molecules and Materials, Analytical Chemistry, P.O. Box 9010, 6500 GL, Nijmegen, The Netherlands.

Flow Cytometry is an analytical technology to simultaneously measure multiple markers per single cell. Ten thousands to millions of single cells can be measured per sample and each sample may contain a different number of cells. All samples may be bundled together, leading to a 'multi-set' structure. Many multivariate methods have been developed for Flow Cytometry data but none of them considers this structure in their quantitative handling of the data. The standard pre-processing used by existing multivariate methods provides models mainly influenced by the samples with more cells, while such a model should provide a balanced view of the biomedical information within all measurements. We propose an alternative 'multi-set' preprocessing that corrects for the difference in number of cells measured, balancing the relative importance of each multi-cell sample in the data while using all data collected from these expensive analyses. Moreover, one case example shows how multi-set pre-processing may benefit removal of undesired measurement-to-measurement variability and another where class-based multi-set pre-processing enhances the studied response upon comparison to the control reference samples. Our results show that adjusting data analysis algorithms to consider this multi-set structure may greatly benefit immunological insight and classification performance of Flow Cytometry data.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-020-66195-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7297713PMC
June 2020

New automated analysis to monitor neutrophil function point-of-care in the intensive care unit after trauma.

Intensive Care Med Exp 2020 Mar 14;8(1):12. Epub 2020 Mar 14.

Department of Trauma Surgery, University Medical Center Utrecht, Heidelberglaan 100, 3584, CX, Utrecht, the Netherlands.

Background: Patients often develop infectious complications after severe trauma. No biomarkers exist that enable early identification of patients who are at risk. Neutrophils are important immune cells that combat these infections by phagocytosis and killing of pathogens. Analysis of neutrophil function used to be laborious and was therefore not applicable in routine diagnostics. Hence, we developed a quick and point-of-care method to assess a critical part of neutrophil function, neutrophil phagosomal acidification. The aim of this study was to investigate whether this method was able to analyze neutrophil functionality in severely injured patients and whether a relation with the development of infectious complications was present.

Results: Fifteen severely injured patients (median ISS of 33) were included, of whom 6 developed an infection between day 4 and day 9 after trauma. The injury severity score did not significantly differ between patients who developed an infection and patients who did not (p = 0.529). Patients who developed an infection showed increased acidification immediately after trauma (p = 0.006) and after 3 days (p = 0.026) and a decrease in the days thereafter to levels in the lower normal range. In contrast, patients who did not develop infectious complications showed high-normal acidification within the first days and increased tasset to identify patients at risk for infections after trauma and to monitor the inflammatory state of these trauma patients.

Conclusion: Neutrophil function can be measured in the ICU setting by rapid point-of-care analysis of phagosomal acidification. This analysis differed between trauma patients who developed infectious complications and trauma patients who did not. Therefore, this assay might prove a valuable asset to identify patients at risk for infections after trauma and to monitor the inflammatory state of these trauma patients.

Trial Registration: Central Committee on Research Involving Human Subjects, NL43279.041.13. Registered 14 February 2014. https://www.toetsingonline.nl/to/ccmo_search.nsf/Searchform?OpenForm.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s40635-020-0299-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7072076PMC
March 2020

On the origin of low-density neutrophils.

J Leukoc Biol 2020 05 14;107(5):809-818. Epub 2020 Mar 14.

Department of Respiratory Medicine and Center for Translational Immunology, University Medical Center Utrecht, The Netherlands.

Here we elaborate on the origin of low(er)-density neutrophils (LDNs) to better understand the variation found in literature. Supplemented with original data, we test the hypothesis that buoyant density of neutrophils is characterized by a spectrum that as a whole shifts to a lower density after activation. Both the 20% highest density (HDNs) and 20% lowest density (LDNs) neutrophils from healthy donors were isolated by Percoll of different densities. Using this method we found that LDNs were significantly better in T-cell suppression and bacterial containment than their 20% highest density counterparts. We found no statistically relevant differences in neutrophil survival or bacterial phagocytosis. Stimulation of healthy donor neutrophils with N-formyl-methionyl-leucyl-phenylalanine induced LDNs co-segregating with peripheral blood mononuclear cells after Ficoll separation. These in vitro induced LDNs showed increased activation markers compared to HDNs and were comparable to the activation markers found on the LDN fraction seen in patients with chronic inflammatory conditions such as present in cancer patients. This all fits with the hypothesis that the density of neutrophils is distributed in a spectrum partially coupled to maturation. Additionally a shift in this spectrum can be induced by in vitro stimulation or by activation in disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/JLB.5HR0120-459RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7318192PMC
May 2020

Persistent Inflammation, Immunosuppression and Catabolism Syndrome (PICS) after Polytrauma: A Rare Syndrome with Major Consequences.

J Clin Med 2020 Jan 10;9(1). Epub 2020 Jan 10.

Department of Trauma Surgery, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands.

Nowadays, more trauma patients develop chronic critical illness (CCI), a state characterized by prolonged intensive care. Some of these CCI patients have disproportional difficulties to recover and suffer from recurrent infections, a syndrome described as the persistent inflammation, immunosuppression and catabolism syndrome (PICS). A total of 78 trauma patients with an ICU stay of ≥14 days (CCI patients) between 2007 and 2017 were retrospectively included. Within this group, PICS patients were identified through two ways: (1) their clinical course (≥3 infectious complications) and (2) by laboratory markers suggested in the literature (C-reactive protein (CRP) and lymphocytes), both in combination with evidence of increased catabolism. The incidence of PICS was 4.7 per 1000 multitrauma patients. The sensitivity and specificity of the laboratory markers was 44% and 73%, respectively. PICS patients had a longer hospital stay (median 83 vs. 40, < 0.001) and required significantly more surgical interventions (median 13 vs. 3, = 0.003) than other CCI patients. Thirteen PICS patients developed sepsis (72%) and 12 (67%) were readmitted at least once due to an infection. In conclusion, patients who develop PICS experience recurrent infectious complications that lead to prolonged hospitalization, many surgical procedures and frequent readmissions. Therefore, PICS forms a substantial burden on the patient and the hospital, despite its low incidence.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/jcm9010191DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7019692PMC
January 2020

Differentiation and activation of eosinophils in the human bone marrow during experimental human endotoxemia.

J Leukoc Biol 2020 11 10;108(5):1665-1671. Epub 2020 Jan 10.

Department of Respiratory Medicine, University Medical Centre Utrecht, Utrecht, The Netherlands.

Acute infection is characterized by eosinopenia. However, the underlying mechanism(s) are poorly understood and it is unclear whether decreased mobilization/production of eosinophils in the bone marrow (BM) and/or increased homing to the tissues play a role. The objective of this study was to investigate the differentiation and activation status of eosinophils in the human BM and blood upon experimental human endotoxemia, a standardized, controlled, and reproducible model of acute systemic inflammation. A BM aspirate and venous blood was obtained from seven healthy volunteers before, 4 h after, and 1 week after intravenous challenge with 2 ng/kg endotoxin. Early progenitors (CD34+/IL-5Rα+), eosinophil promyelocytes, myelocytes, metamyelocytes, and mature eosinophils were identified and quantified in the bone marrow and blood samples using flowcytometry based on specific eosinophil markers (CD193 and IL-5Rα). Activation status was assessed using antibodies against known markers on eosinophils: Alpha-4 (CD49d), CCR3 (CD193), CR1 (CD35), CEACAM-8 (CD66b), CBRM 1/5 (activation epitope of MAC-1), and by plasma cytokine analysis. Four hours after endotoxin administration, numbers of mature eosinophils in the blood and in the BM markedly declined compared with baseline, whereas numbers of all eosinophil progenitors did not change. The remaining eosinophils did not show signs of activation or degranulation despite significantly increased circulating levels of eotaxin-1. Furthermore, the expression of CD49d and CD193 on eosinophils was lower compared to baseline, but normalized after 7 days. Together these data imply that circulatory eosinopenia after an innate immune challenge is mediated by CD49d-mediated homing of eosinophils to the tissues.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/JLB.1AB1219-493RDOI Listing
November 2020

Neutrophil Heterogeneity in Cancer: From Biology to Therapies.

Front Immunol 2019 20;10:2155. Epub 2019 Sep 20.

Department of Immunity, Virus, and Inflammation (IVI), Centre de Recherche en Cancérologie de Lyon, Centre Léon Bérard, University of Lyon, Université Claude Bernard Lyon 1, INSERM 1052, CNRS 5286, Lyon, France.

Neutrophils have been extensively described in the pathophysiology of autoimmune and infectious diseases. Accumulating evidence also suggests the important role of neutrophils in cancer progression through their interaction with cancer and immune cells in blood and in the tumor microenvironment (TME). Most studies have described neutrophils as key drivers of cancer progression, due to their involvement in various tumor promoting functions including proliferation, aggressiveness, and dissemination, as well as in immune suppression. However, such studies were focusing on late-stages of tumorigenesis, in which chronic inflammation had already developed. The role of tumor-associated neutrophils (TANs) at early stages of tumor development remains poorly described, though recent findings indicate that early-stage TANs may display anti-tumor properties. Beyond their role at tumor site, evidence supported by NLR retrospective studies and functional analyses suggest that blood neutrophils could also actively contribute to tumorigenesis. Hence, it appears that the phenotype and functions of neutrophils vary greatly during tumor progression, highlighting their heterogeneity. The origin of pro- or anti-tumor neutrophils is generally believed to arise following a change in cell state, from resting to activated. Moreover, the fate of neutrophils may also involve distinct differentiation programs yielding various subsets of pro or anti-tumor neutrophils. In this review, we will discuss the current knowledge on neutrophils heterogeneity across different tissues and their impact on tumorigenesis, as well as neutrophil-based therapeutic strategies that have shown promising results in pre-clinical studies, paving the way for the design of neutrophil-based next generation immunotherapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2019.02155DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6764113PMC
October 2020

Automated flow cytometry enables high performance point-of-care analysis of leukocyte phenotypes.

J Immunol Methods 2019 11 13;474:112646. Epub 2019 Aug 13.

Laboratory of Translational Immunology (LTI) and Department of Respiratory Medicine, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands. Electronic address:

Introduction: Phagocytes such as granulocytes and monocytes are fundamental players in the innate immune system. Activation of these cells can be quantified by the measurement of activation marker expression using flow cytometry. Analysis of receptor expression on inflammatory cells facilitates the diagnosis of inflammatory diseases and can be used to determine the extent of inflammation. However, several major limitations of this analysis precludes application of inflammation monitoring in clinical practice. Fast and automated analysis would minimalize ex vivo manipulation and allow reproducible processing. The aim of this study was to evaluate a fully automated "load & go" flow cytometer for analyzing activation of granulocytes and monocytes in a clinically applicable setting.

Methods: Blood samples were obtained from 10 anonymous and healthy volunteers between the age of 18 and 65 years. Granulocyte and monocyte activation was determined by the use of the markers CD35, CD11b and CD10 measured in the automated AQUIOS CL® "load & go" flow cytometer. This machine is able to pierce the tube caps, add antibodies, lyse and measure the sample within 20 min after vena puncture. Reproducibility tests were performed to test the stability of activation marker expression on phagocytes. The expression of activation markers was measured at different time points after blood drawing to analyze the effect of bench time on granulocyte and monocyte activation.

Results: The duplicate experiments demonstrate a high reproducibility of the measurements of the activation state of phagocytes. Healthy controls showed a very homogenous expression of activation markers at T = 0 (immediately after vena puncture). Activation markers on neutrophils were already significantly increased after 1 h (T = 1) depicted as means (95%Cl) CD35: 2.2× (1.5×-2.5×) p = .028, CD11b: 2.5× (1.7×-3.1×) p = .023, CD10: 2.5× (2.1×-2.7×) p = .009) and a further increase in activation markers was observed after 2 and 3 h. Monocytes also showed a increase in activation markers in 1 h (mean (95%Cl) CD35: 1.8× (1.3×-2.2×) p = .058, CD11b: 2.13× (1.6×-2.4×) p = .025) and also a further significant increase in 2 and 3 h was observed.

Conclusion: This study showed that bench time of one hour already leads to a significant upregulation and bigger variance in activation markers of granulocytes and monocytes. In addition, it is likely that automated flow cytometry reduces intra-assay variability in the analysis of activation markers on inflammatory cells. Therefore, we found that it is of utmost importance to perform immune activation analysis as fast as possible to prevent drawing wrong conclusions. Automated flow cytometry is able to reduce this analysis from 2 h to only 15-20 min without the need of dedicated personnel and in a point-of-care context. This now allows fast and automated inflammation monitoring in blood samples obtained from a variety of patient groups. FUND: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jim.2019.112646DOI Listing
November 2019

Neutrophil heterogeneity and its role in infectious complications after severe trauma.

World J Emerg Surg 2019 29;14:24. Epub 2019 May 29.

1Department of Trauma Surgery, University Medical Centre Utrecht, Utrecht, The Netherlands.

Background: Trauma leads to a complex inflammatory cascade that induces both immune activation and a refractory immune state in parallel. Although both components are deemed necessary for recovery, the balance is tight and easily lost. Losing the balance can lead to life-threatening infectious complications as well as long-term immunosuppression with recurrent infections. Neutrophils are known to play a key role in these processes. Therefore, this review focuses on neutrophil characteristics and function after trauma and how these features can be used to identify trauma patients at risk for infectious complications.

Results: Distinct neutrophil subtypes exist that play their own role in the recovery and/or development of infectious complications after trauma. Furthermore, the refractory immune state is related to the risk of infectious complications. These findings change the initial concepts of the immune response after trauma and give rise to new biomarkers for monitoring and predicting inflammatory complications in severely injured patients.

Conclusion: For early recognition of patients at risk, the immune system should be monitored. Several neutrophil biomarkers show promising results and analysis of these markers has become accessible to such extent that they can be used for point-of-care decision making after trauma.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13017-019-0244-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6542247PMC
September 2019

The Neutrophil Life Cycle.

Trends Immunol 2019 07 29;40(7):584-597. Epub 2019 May 29.

Laboratory of Translational Immunology, Department of Respiratory Medicine, University Medical Centre Utrecht, Utrecht, The Netherlands. Electronic address:

Neutrophils are recognized as an essential part of the innate immune response, but an active debate still exists regarding the life cycle of these cells. Neutrophils first differentiate in the bone marrow through progenitor intermediaries before entering the blood, in a process that gauges the extramedullary pool size. Once believed to be directly eliminated in the marrow, liver, and spleen, neutrophils, after circulating for less than 1 day, are now known to redistribute into multiple tissues with poorly understood kinetics. In this review, we provide an update on the dynamic distribution of neutrophils across tissues in health and disease, and emphasize differences between humans and model organisms. We further highlight issues to be addressed to exploit the unique features of neutrophils in the clinic.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.it.2019.04.013DOI Listing
July 2019

Corrigendum: Inside-Out Control of Fc-Receptors.

Authors:
Leo Koenderman

Front Immunol 2019 7;10:971. Epub 2019 May 7.

Department of Respiratory Medicine and Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht, Netherlands.

[This corrects the article DOI: 10.3389/fimmu.2019.00544.].
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2019.00971DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6514182PMC
May 2019

Intracellular Penetration and Effects of Antibiotics on Inside Human Neutrophils: A Comprehensive Review.

Antibiotics (Basel) 2019 May 4;8(2). Epub 2019 May 4.

Department of Surgery, University Medical Center Utrecht, 3508 GA Utrecht, The Netherlands.

Neutrophils are important assets in defense against invading bacteria like staphylococci. However, (dysfunctioning) neutrophils can also serve as reservoir for pathogens that are able to survive inside the cellular environment. is a notorious facultative intracellular pathogen. Most vulnerable for neutrophil dysfunction and intracellular infection are immune-deficient patients or, as has recently been described, severely injured patients. These dysfunctional neutrophils can become hide-out spots or "Trojan horses" for . This location offers protection to bacteria from most antibiotics and allows transportation of bacteria throughout the body inside moving neutrophils. When neutrophils die, these bacteria are released at different locations. In this review, we therefore focus on the capacity of several groups of antibiotics to enter human neutrophils, kill intracellular . and affect neutrophil function. We provide an overview of intracellular capacity of available antibiotics to aid in clinical decision making. In conclusion, quinolones, rifamycins and sulfamethoxazole-trimethoprim seem very effective against intracellular in human neutrophils. Oxazolidinones, macrolides and lincosamides also exert intracellular antibiotic activity. Despite that the reviewed data are predominantly of in vitro origin, these findings should be taken into account when intracellular infection is suspected, as can be the case in severely injured patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/antibiotics8020054DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6628357PMC
May 2019

A novel data fusion method for the effective analysis of multiple panels of flow cytometry data.

Sci Rep 2019 05 1;9(1):6777. Epub 2019 May 1.

Radboud University, Institute for Molecules and Materials (Analytical Chemistry), postvak 61, P.O. Box 9010, 6500 GL, Nijmegen, The Netherlands.

Multicolour flow cytometry (MFC) is used to measure multiple cellular markers at the single-cell level. Cellular markers may be coloured with different panels of fluorescently-labelled antibodies to enable cell identification or the detection of activated cells in pre-defined, 'gated' specific cell subsets. The number of markers that can be used per measurement is technologically limited however, requiring every panel to be analysed in a separate aliquot measurement. The combined analyses of these dedicated panels may enhance the predictive ability of these measurements and could enrich the interpretation of the immunological information. Here we introduce a fusion method for MFC data, based on DAMACY (Discriminant Analysis of Multi-Aspect Cytometry data), which can combine information from complementary panels. This approach leads to both enhanced predictions and clearer interpretations in comparison with the analysis of separate measurements. We illustrate this method using two datasets: the response of neutrophils evoked by a systemic endotoxin challenge and the activated immune status of the innate cells, T cells and B cells in obese versus lean individuals. The data fusion approach was able to detect cells that do not individually show a difference between clinical phenotypes but do play a role in combination with other cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-019-43166-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6494873PMC
May 2019

Inside-Out Control of Fc-Receptors.

Authors:
Leo Koenderman

Front Immunol 2019 21;10:544. Epub 2019 Mar 21.

Department of Respiratory Medicine and Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht, Netherlands.

Receptors recognizing the Fc-part of immunoglobulins (FcR) are important in the engagement of phagocytes with opsonized micro-organisms, but they also play a major role in the pathogenesis of chronic inflammatory diseases. Different FcRs are specifically recognizing and binding the different classes of immunoglobulins, transmitting different signals into the cell. The function of IgG (FcγR's) and IgA (FcαR) recognizing receptors is controlled by cellular signals evoked by activation of heterologous receptors in a process generally referred to as inside-out control. This concept is clearly described for the regulation of integrin receptors. Inside-out control can be achieved at different levels by modulation of: (i) receptor affinity, (ii) receptor avidity/valency, (iii) interaction with signaling chains, (iv) interaction with other receptors and (v) localization in functionally different membrane domains. The inside-out control of FcRs is an interesting target for novel therapy by therapeutical antibodies as it can potentiate or decrease the functionality of the response to the antibodies depending on the mechanisms of the diseases they are applied for.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2019.00544DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6437074PMC
September 2020

Eosinophils capture viruses, a capacity that is defective in asthma.

Allergy 2019 10 15;74(10):1898-1909. Epub 2019 May 15.

Department Respiratory Medicine, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands.

Background: Activated eosinophils cause major pathology in stable and exacerbating asthma; however, they can also display protective properties like an extracellular antiviral activity. Initial murine studies led us to further explore a potential intracellular antiviral activity by eosinophils.

Methods: To follow eosinophil-virus interaction, respiratory syncytial virus (RSV) and influenza virus were labeled with a fluorescent lipophilic dye (DiD). Interactions with eosinophils were visualized by confocal microscopy, electron microscopy, and flow cytometry. Eosinophil activation was assessed by both flow cytometry and ELISA. In a separate study, eosinophils were depleted in asthma patients using anti-IL-5 (mepolizumab), followed by a challenge with rhinovirus-16 (RV16).

Results: DiD-RSV and DiD-influenza rapidly adhered to human eosinophils and were internalized and inactivated (95% in ≤ 2 hours) as reflected by a reduced replication in epithelial cells. The capacity of eosinophils to capture virus was reduced up to 75% with increasing severity of asthma. Eosinophils were activated by virus in vitro and in vivo. In vivo this correlated with virus-induced loss of asthma control.

Conclusions: This previously unrecognized and in asthma attenuated antiviral property provides a new perspective to eosinophils in asthma. This is indicative of an imbalance between protective and cytotoxic properties by eosinophils that may underlie asthma exacerbations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/all.13802DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6852198PMC
October 2019

Common Infections and Target Organs Associated with Chronic Granulomatous Disease in Iran.

Int Arch Allergy Immunol 2019;179(1):62-73. Epub 2019 Mar 22.

Cell and Molecular Biology Group, Airways Disease Section, National Heart and Lung Institute, Imperial College London, London, United Kingdom,

Recurrent severe bacterial and fungal infections are characteristic features of the rare genetic immunodeficiency disorder chronic granulomatous disease (CGD). The disease usually manifests within the first years of life with an incidence of 1 in approximately 200,000 live births. The incidence is higher in Iran and Morocco where it reaches 1.5 per 100,000 live births. Mutations have been described in the 5 subunits of NADPH oxidase, mostly in gp91phox and p47phox, with fewer mutations reported in p67phox, p22phox, and p40phox. These mutations cause loss of superoxide production in phagocytic cells. CYBB, the gene encoding the large gp91phox subunit of the transmembrane component cytochrome b558 of the NADPH oxidase complex, is localized on the X-chromosome. Genetic defects in CYBB are responsible for the disease in the majority of male CGD patients. CGD is associated with the development of granulomatous reactions in the skin, lungs, bones, and lymph nodes, and chronic infections may be seen in the liver, gastrointestinal tract, brain, and eyes. There is usually a history of repeated infections, including inflammation of the lymph glands, skin infections, and pneumonia. There may also be a persistent runny nose, inflammation of the skin, and inflammation of the mucous membranes of the mouth. Gastrointestinal problems can also occur, including diarrhea, abdominal pain, and perianal abscesses. Infection of the bones, brain abscesses, obstruction of the genitourinary tract and/or gastrointestinal tract due to the formation of granulomatous tissue, and delayed growth are also symptomatic of CGD. The prevention of infectious complications in patients with CGD involves targeted prophylaxis against opportunistic microorganisms such as Staphylococcus aureus, Klebsiella spp., Salmonella spp. and Aspergillus spp. In this review, we provide an update on organ involvement and the association with specific isolated microorganisms in CGD patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1159/000496181DOI Listing
May 2019

FcαRI Dynamics Are Regulated by GSK-3 and PKCζ During Cytokine Mediated Inside-Out Signaling.

Front Immunol 2018 31;9:3191. Epub 2019 Jan 31.

Laboratory of Translational Immunology, University Medical Center, Utrecht, Netherlands.

IgA binding to FcαRI (CD89) is rapidly enhanced by cytokine induced inside-out signaling. Dephosphorylation of serine 263 in the intracellular tail of FcαRI by PP2A and PI3K activation are instrumental in this process. To further investigate these signaling pathways, we targeted downstream kinases of PI3K. Our experiments revealed that PI3K activates PKCζ, which subsequently inhibits GSK-3, a constitutively active kinase in resting cells and found here to be associated with FcαRI. We propose that GSK-3 maintains FcαRI in an inactive state at homeostatic conditions. Upon cytokine stimulation, GSK-3 is inactivated through a PI3K-PKCζ pathway, preventing the maintenance of phosphorylated inactive FcαRI. The concomitantly activated PP2A is then able to dephosphorylate and activate FcαRI. Moreover, FRAP and FLIP studies showed that FcαRI activation coincides with an increased mobile fraction of the receptor. This can enhance FcαRI valency and contribute to stronger avidity for IgA immune complexes. This tightly regulated inside-out signaling pathway allows leukocytes to respond rapidly and efficiently to their environment and could be exploited to enhance the efficacy of future IgA therapeutics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2018.03191DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6365424PMC
October 2019

Submaximal heart rate seems inadequate to prescribe and monitor intensified training.

Eur J Sport Sci 2019 Sep 14;19(8):1082-1091. Epub 2019 Feb 14.

a Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences , Vrije Universiteit Amsterdam , Amsterdam , Netherlands.

The aim of this study is to investigate whether the change in (sub)maximal heart rate after intensified training is associated with the change in performance. Thirty subjects were recruited who performed cardiopulmonary exercise tests to exhaustion 2 weeks before (pre), 1 week after (post) and 5 weeks after (follow-up) an 8-day non-competitive amateur cycling event (TFL). The exercise volume during the TFL was 7.7 fold the volume during the preparation period. Heart rate and cardiopulmonary parameters were obtained at standardised absolute submaximal workloads (low, medium and high intensity) and at peak level each test. Subjects were classified as functionally overreached (FOR) or acute fatigued (AF) based on the change in performance. No differences between FOR and AF were observed for heart rate ( = .51). On total group level (AF + FOR), post-TFL heart rate decreased significantly at low (-4.4 beats·min, 95% CI [-8.7, -0.1]) and medium (-5.5 beats·min [-8.5, -2.4]), but not at high intensity. Peak heart rate decreased -3.4 beats·min [-6.1, -0.7]. Opulse was on average 0.49 ml O·beat [0.09, 0.89] higher at all intensities after intensified training. No changes in ⩒O ( = .44) or the ventilatory threshold ( = .21) were observed. Pearson's correlation coefficients revealed negative associations between heart rate and Opulse at low ( = -.56,  < .01) and medium intensity ( = -.54,  < .01), but not with ⩒O or any other submaximal parameter. (Sub)maximal heart rate decreased after the TFL. However, this decrease is unrelated to the change in performance. Therefore, heart rate seems inadequate to prescribe and monitor intensified training.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/17461391.2019.1571112DOI Listing
September 2019