A single bout of vigorous intensity exercise enhances the efficacy of rituximab against human chronic lymphocytic leukaemia B-cells ex vivo.

Chronic lymphocytic leukaemia (CLL) is characterised by the clonal proliferation and accumulation of mature B-cells and is often treated with rituximab, an anti-CD20 monoclonal antibody immunotherapy. Rituximab often fails to induce stringent disease eradication, due in part to failure of antibody-dependent cellular cytotoxicity (ADCC) which relies on natural killer (NK)-cells binding to rituximab-bound CD20 on B-cells. CLL cells are diffusely spread across lymphoid and other bodily tissues, and ADCC resistance in survival niches may be due to several factors including low NK-cell frequency and a suppressive stromal environment that promotes CLL cell survival. It is well established that exercise bouts induce a transient relocation of NK-cells and B-cells into peripheral blood, which could be harnessed to enhance the efficacy of rituximab in CLL by relocating both target and effector cells together with rituximab in blood. In this pilot study, n = 20 patients with treatment-naïve CLL completed a bout of cycling 15 % above anaerobic threshold for âˆ¼ 30-minutes, with blood samples collected pre-, immediately post-, and 1-hour post-exercise. Flow cytometry revealed that exercise evoked a 254 % increase in effector (CD3-CD56+CD16+) NK-cells in blood, and a 67 % increase in CD5+CD19+CD20+ CLL cells in blood (all p < 0.005). NK-cells were isolated from blood samples pre-, and immediately post-exercise and incubated with primary isolated CLL cells with or without the presence of rituximab to determine specific lysis using a calcein-release assay. Rituximab-mediated cell lysis increased by 129 % following exercise (p < 0.001). Direct NK-cell lysis of CLL cells - independent of rituximab - was unchanged following exercise (p = 0.25). We conclude that exercise improved the efficacy of rituximab-mediated ADCC against autologous CLL cells ex vivo and propose that exercise should be explored as a means of enhancing clinical responses in patients receiving anti-CD20 immunotherapy.

The effects of exercise on complement system proteins in humans: a systematic scoping review.

BACKGROUND: The complement system is comprised of the classical, lectin and alternative pathways that result in the formation of: pro-inflammatory anaphylatoxins; opsonins that label cells for phagocytic removal; and, a membrane attack complex that directly lyses target cells. Complement-dependent cytotoxicity (CDC) - cell lysis triggered by complement protein C1q binding to the Fc region of antibodies bound to target cells - is another effector function of complement and a key mechanism-of-action of several monoclonal antibody therapies. At present, it is not well established how exercise affects complement system proteins in humans. METHODS: A systematic search was conducted to identify studies that included original data and investigated the association between soluble complement proteins in the blood of healthy humans, and: 1) an acute bout of exercise; 2) exercise training interventions; or, 3) measurements of habitual physical activity and fitness. RESULTS: 77 studies were eligible for inclusion in this review, which included a total of 10,236 participants, and 40 complement proteins and constituent fragments. Higher levels of exercise training and cardiorespiratory fitness were commonly associated with reduced C3 in blood. Additionally, muscle strength was negatively associated with C1q. Elevated C3a-des-Arg, C4a-des-Arg and C5a, lower C1-inhibitor, and unchanged C3 and C4 were reported immediately post-laboratory based exercise, compared to baseline. Whereas, ultra-endurance running and resistance training increased markers of the alternative (factor B and H), classical (C1s), and leptin (mannose binding lectin) pathways, as well as C3 and C6 family proteins, up to 72-h following exercise. Heterogeneity among studies may be due to discrepancies in blood sampling/handling procedures, analytical techniques, exercise interventions/measurements and fitness of included populations. CONCLUSIONS: Increased anaphylatoxins were observed immediately following an acute bout of exercise in a laboratory setting, whereas field-based exercise interventions of a longer duration (e.g. ultra-endurance running) or designed to elicit muscle damage (e.g. resistance training) increased complement proteins for up to 72-h. C3 in blood was mostly reduced by exercise training and associated with increased cardiorespiratory fitness, whereas C1q appeared to be negatively associated to muscle strength. Thus, both acute bouts of exercise and exercise training appear to modulate complement system proteins. Future research is needed to assess the clinical implications of these changes, for example on the efficacy of monoclonal antibody therapies dependent on CDC.

The impact of plasma 25-hydroxyvitamin D on pulmonary function and exercise physiology in cystic fibrosis: A multicentre retrospective study.

BACKGROUND: A 25-hydroxyvitamin D (25OHD) may exert immunomodulatory effects on respiratory health, which may translate to improvements in exercise physiology. Thus, we aimed to investigate whether plasma 25OHD is associated with lung function and aerobic fitness in people with cystic fibrosis (pwCF). METHODS: A multicentre retrospective review of pwCF (> 9 years old) attending the Royal Hospital for Sick Children (Edinburgh) or Wessex CF-Unit (Southampton) was performed between July 2017 and October 2019. Demographic and clinical data were collected. Plasma 25OHD measured closest in time to clinical cardiopulmonary exercise testing and/or spirometry [forced expiratory volume (FEV1 )% predicted] was recorded. Pancreatic insufficiency was diagnosed based on faecal elastase of < 100 µg g-1 . We performed multiple-regression analysis with aerobic fitness outcomes [peak oxygen uptake (VO2 peak )] and FEV1 % predicted as primary outcomes. RESULTS: Ninety pwCF [mean ± SD age: 19.1 ± 8.6 years, 54 (60%) children, 48 (53%) males and 88 (98%) Caucasian] were included. 25OHD deficiency and insufficiency was 15 (17%) and 44 (49%), respectively. 25OHD deficiency and insufficiency was significantly associated with pancreatic insufficiency (χ2  = 4.8, p = 0.02). Plasma 25OHD was not significantly associated with FEV1 % predicted (r2  = 0.06, p = 0.42, 95% CI = -0.09 to 0.19) or VO2 peak (r2  = 0.04, p = 0.07, 95% CI = -011 to 0.005) in all pwCF. However, 25OHD was significantly associated with both FEV1 % (r2  = 0.15, p = 0.02, 95% CI = 1.99-2.64) and VO2 peak (r2  = 0.13, p = 0.05, 95% CI = -0.26 to -0.005) in the paediatric cohort. CONCLUSIONS: We showed that 25OHD is associated with improved lung function and aerobic fitness in children and adolescents with CF. Mechanistic and high-quality prospective studies including both lung function and aerobic fitness as primary outcomes are now warranted.

The Exeter Activity Unlimited statement on physical activity and exercise for cystic fibrosis: methodology and results of an international, multidisciplinary, evidence-driven expert consensus.

BACKGROUND: The roles of physical activity (PA) and exercise within the management of cystic fibrosis (CF) are recognised by their inclusion in numerous standards of care and treatment guidelines. However, information is brief, and both PA and exercise as multi-faceted behaviours require extensive stakeholder input when developing and promoting such guidelines. METHOD: On 30th June and 1st July 2021, 39 stakeholders from 11 countries, including researchers, healthcare professionals and patients participated in a virtual conference to agree an evidence-based and informed expert consensus about PA and exercise for people with CF. This consensus presents the agreement across six themes: (i) patient and system centred outcomes, (ii) health benefits, iii) measurement, (iv) prescription, (v) clinical considerations, and (vi) future directions. The consensus was achieved by a stepwise process, involving: (i) written evidence-based synopses; (ii) peer critique of synopses; (iii) oral presentation to consensus group and peer challenge of revised synopses; and (iv) anonymous voting on final proposed synopses for adoption to the consensus statement. RESULTS: The final consensus document includes 24 statements which surpassed the consensus threshold (>80% agreement) out of 30 proposed statements. CONCLUSION: This consensus can be used to support health promotion by relevant stakeholders for people with CF.

Characterising how a single bout of exercise in people with myeloma affects clonal plasma cell and immune effector cell frequency in blood, and daratumumab efficacy in vitro.

Multiple myeloma is a haematological cancer characterised by the accumulation of clonal plasma cells in the bone marrow and is commonly treated with daratumumab, an anti-CD38 monoclonal antibody immunotherapy. Daratumumab often fails to induce stringent complete responses, due in part to resistance to antibody-dependent cellular cytotoxicity (ADCC) exerted by natural killer (NK)-cells and monocytes. Exercise bouts undertaken by healthy people induce lymphocytosis in blood, including to NK-cells and B-cells, but the effects of exercise are unknown in myeloma patients. In addition, whether exercise mobilises plasma cells has not been adequately investigated, and as such the potential impact of exercise on daratumumab treatment is unclear. In this exploratory pilot study, n = 16 smouldering multiple myeloma participants enrolled and n = 9 completed the study which comprised a bout of cycling 15% above anaerobic threshold for ∼30-min, with blood samples collected pre-, immediately post-, and 30-min post-exercise. Peripheral blood mononuclear cells were isolated from blood samples and incubated with the RPMI-8226 plasmacytoma cell line, with or without the presence of daratumumab to determine specific lysis using a calcein-release assay. Daratumumab-mediated cell lysis increased from 18.8% to 23.2% pre- to post-exercise, respectively (p < 0.001), owing to an increased frequency of CD3-CD56+CD16+ NK-cells (+348%), HLA-DR+CD14dimCD16+ monocytes (+125%), and HLA-DR+CD14+CD32+ monocytes (+41%) in blood (p < 0.01). However, overall, total plasma cells (CD38+CD138+) nor clonal plasma cells (CD38brightCD138+CD45-/dimCD19- with light-chain restriction) increased in blood (p > 0.05). Notably, we observed a 305% increase in NK-cells expressing CD38, the daratumumab target antigen, which might render NK-cells more susceptible to daratumumab-mediated fratricide - whereby NK-cells initiate ADCC against daratumumab-bound NK-cells. In conclusion, exercise modestly improved the efficacy of daratumumab-mediated ADCC in vitro. However, plasma cells were largely unchanged, and NK-cells expressing CD38 - the daratumumab target antigen - increased in blood. Future research should consider the optimal timings of exercise during daratumumab treatment in myeloma to avert exacerbation of daratumumab-mediated NK-cell lysis.

The effects of sleep deprivation, acute hypoxia, and exercise on cognitive performance: A multi-experiment combined stressors study.

INTRODUCTION: Both sleep deprivation and hypoxia have been shown to impair executive function. Conversely, moderate intensity exercise is known to improve executive function. In a multi-experiment study, we tested the hypotheses that moderate intensity exercise would ameliorate any decline in executive function after i) three consecutive nights of partial sleep deprivation (PSD) (Experiment 1) and ii) the isolated and combined effects of a single night of total sleep deprivation (TSD) and acute hypoxia (Experiment 2). METHODS: Using a rigorous randomised controlled crossover design, 12 healthy participants volunteered in each experiment (24 total, 5 females). In both experiments seven executive function tasks (2-choice reaction time, logical relations, manikin, mathematical processing, 1-back, 2-back, 3-back) were completed at rest and during 20 min semi-recumbent, moderate intensity cycling. Tasks were completed in the following conditions: before and after three consecutive nights of PSD and habitual sleep (Experiment 1) and in normoxia and acute hypoxia (FIO2 = 0.12) following one night of habitual sleep and one night of TSD (Experiment 2). RESULTS: Although the effects of three nights of PSD on executive functions were inconsistent, one night of TSD (regardless of hypoxic status) reduced executive functions. Significantly, regardless of sleep or hypoxic status, executive functions are improved during an acute bout of moderate intensity exercise. CONCLUSION: These novel data indicate that moderate intensity exercise improves executive function performance after both PSD and TSD, regardless of hypoxic status. The key determinants and/or mechanism(s) responsible for this improvement still need to be elucidated. Future work should seek to identify these mechanisms and translate these significant findings into occupational and skilled performance settings.

Cardiopulmonary Exercise Testing Provides Prognostic Information in Advanced Cystic Fibrosis Lung Disease.

Rationale: Cardiopulmonary exercise testing (CPET) provides prognostic information in cystic fibrosis (CF); however, its prognostic value for patients with advanced CF lung disease is unknown. Objectives: To determine the prognostic value of CPET on the risk of death or lung transplant (LTX) within 2 years. Methods: We retrospectively collected data from 20 CF centers in Asia, Australia, Europe, and North America on patients with a forced expiratory volume in 1 second (FEV1) ⩽ 40% predicted who performed a cycle ergometer CPET between January 2008 and December 2017. Time to death/LTX was analyzed using mixed Cox proportional hazards regression. Conditional inference trees were modeled to identify subgroups with increased risk of death/LTX. Results: In total, 174 patients (FEV1, 30.9% ± 5.8% predicted) were included. Forty-four patients (25.5%) died or underwent LTX. Cox regression analysis adjusted for age, sex, and FEV1 revealed percentage predicted peak oxygen uptake ([Formula: see text]o2peak) and peak work rate (Wpeak) as significant predictors of death/LTX: adjusted hazard ratios per each additional 10% predicted were 0.60 (95% confidence interval, 0.43-0.90; P = 0.008) and 0.60 (0.48-0.82; P < 0.001). Tree-structured regression models, including a set of 11 prognostic factors for survival, identified Wpeak to be most strongly associated with 2-year risk of death/LTX. Probability of death/LTX was 45.2% for those with a Wpeak ⩽ 49.2% predicted versus 10.9% for those with a Wpeak > 49.2% predicted (P < 0.001). Conclusions: CPET provides prognostic information in advanced CF lung disease, and Wpeak appears to be a promising marker for LTX referral and candidate selection.

Oral Temperature and pH Influence Dietary Nitrate Metabolism in Healthy Adults.

This study tested the hypothesis that the increases in salivary and plasma [NO2-] after dietary NO3- supplementation would be greater when oral temperature and pH were independently elevated, and increased further when oral temperature and pH were elevated concurrently. Seven healthy males (mean ± SD, age 23 ± 4 years) ingested 70 mL of beetroot juice concentrate (BR, which provided ~6.2 mmol NO3-) during six separate laboratory visits. In a randomised crossover experimental design, salivary and plasma [NO3-] and [NO2-] were assessed at a neutral oral pH with a low (TLo-pHNorm), intermediate (TMid-pHNorm), and high (THi-pHNorm) oral temperature, and when the oral pH was increased at a low (TLo-pHHi), intermediate (TMid-pHHi), and high (THi-pHHi) oral temperature. Compared with the TMid-pHNorm condition (976 ± 388 µM), the mean salivary [NO2-] 1-3 h post BR ingestion was higher in the TMid-pHHi (1855 ± 423 µM), THi-pHNorm (1371 ± 653 µM), THi-pHHi (1792 ± 741 µM), TLo-pHNorm (1495 ± 502 µM), and TLo-pHHi (2013 ± 662 µM) conditions, with salivary [NO2-] also higher at a given oral temperature when the oral pH was increased (p < 0.05). Plasma [NO2-] was higher 3 h post BR ingestion in the TMid-pHHi, THi-pHHi, and TLo-pHHi conditions, but not the TLo-pHNorm and THi-pHNorm conditions, compared with TMid-pHNorm (p < 0.05). Therefore, despite ingesting the same NO3- dose, the increases in salivary [NO2-] varied depending on the temperature and pH of the oral cavity, while the plasma [NO2-] increased independently of oral temperature, but to a greater extent at a higher oral pH.

Harnessing the immunomodulatory effects of exercise to enhance the efficacy of monoclonal antibody therapies against B-cell haematological cancers: a narrative review.

Therapeutic monoclonal antibodies (mAbs) are standard care for many B-cell haematological cancers. The modes of action for these mAbs include: induction of cancer cell lysis by activating Fcγ-receptors on innate immune cells; opsonising target cells for antibody-dependent cellular cytotoxicity or phagocytosis, and/or triggering the classical complement pathway; the simultaneous binding of cancer cells with T-cells to create an immune synapse and activate perforin-mediated T-cell cytotoxicity against cancer cells; blockade of immune checkpoints to facilitate T-cell cytotoxicity against immunogenic cancer cell clones; and direct delivery of cytotoxic agents via internalisation of mAbs by target cells. While treatment regimens comprising mAb therapy can lead to durable anti-cancer responses, disease relapse is common due to failure of mAb therapy to eradicate minimal residual disease. Factors that limit mAb efficacy include: suboptimal effector cell frequencies, overt immune exhaustion and/or immune anergy, and survival of diffusely spread tumour cells in different stromal niches. In this review, we discuss how immunomodulatory changes arising from exposure to structured bouts of acute exercise might improve mAb treatment efficacy by augmenting (i) antibody-dependent cellular cytotoxicity, (ii) antibody-dependent cellular phagocytosis, (iii) complement-dependent cytotoxicity, (iv) T-cell cytotoxicity, and (v) direct delivery of cytotoxic agents.

Elexacaftor-Tezacaftor-Ivacaftor improves exercise capacity in adolescents with cystic fibrosis.

OBJECTIVE: Elexacaftor/Tezacaftor/Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) modulator with the potential to improve exercise capacity. This case series of three adolescents with CF aimed to investigate whether 6 weeks treatment with Elexacaftor/Tezacaftor/Ivacaftor could improve exercise capacity in CFTR modulator naive adolescents with CF. METHODS: Three adolescents (14.0 ± 1.4 years) with CF (FEV1 % predicted: 62.5 ± 17.1; F508del/F508del genotype) completed an exhaustive maximal cardiopulmonary exercise test on a cycle ergometer to determine peak oxygen uptake ( V ̇ $\dot{{\rm{V}}}$ O2peak ) and measure changes in gas exchange and ventilation during exercise at 6 weeks. We also analyzed wrist-worn device-based physical activity (PA) data in two of the three cases. Validated acceleration thresholds were used to quantify time spent in each PA intensity category. RESULTS: Clinically meaningful improvements in V ̇ $\dot{{\rm{V}}}$ O2peak were observed in all three cases (+17.6%, +52.4%, and +32.9%, respectively), with improvements greatest in those with more severe lung disease and lower fitness at baseline. Although lung function increased in all cases, inconsistent changes in markers of ventilatory and peripheral muscle efficiency likely suggest different mechanisms of improvement in this case group of adolescents with CF. Device-based analysis of PA was variable, with one case increasing and one case decreasing. CONCLUSION: In this case series, we have observed, for the first time, improvements in exercise capacity following 6 weeks of treatment with Elexacaftor/Tezacaftor/Ivacaftor. Improvements were greatest in the presence of more severe CF lung disease and lower aerobic fitness at baseline. The mechanism(s) responsible for these changes warrant further investigation in larger trials.

Heat acclimation improves sweat gland function and lowers sweat sodium concentration in an adult with cystic fibrosis.

We present novel data concerning the time-course of adaptations and potential benefits of heat acclimation for people with cystic fibrosis (pwCF), who are at greater risk of exertional heat illness. A 25-year-old male (genotype: delta-F508 and RH117, forced expiratory volume in 1-second: 77% predicted and baseline sweat [Na+]: 70 mmol·L - 1), who had previously experienced muscle cramping during exercise in ambient heat, underwent 10-sessions of heat acclimation (90-min at 40°C and in 40% relative humidity). Adaptations included; lower resting core temperature (-0.40°C) and heart rate (-6 beats·min-1), plasma volume expansion (+6.0%) and, importantly, increased sweat loss (+370 mL) and sweat gland activity (+12 glands·cm2) with decreased sweat [Na+] (-18 mmol·L - 1). Adaptations were maintained for at least 7-days, with no evidence of cramping during follow-up exercise-heat stress testing. These data suggest pwCF may benefit from heat acclimation to induce sudomotor function improvements, particularly reductions in sweat [Na+], however, further research is required.

CFTR limits F-actin formation and promotes morphological alignment with flow in human lung microvascular endothelial cells.

Micro- and macrovascular endothelial dysfunction in response to shear stress has been observed in cystic fibrosis (CF), and has been associated with inflammation and oxidative stress. We tested the hypothesis that the cystic fibrosis transmembrane conductance regulator (CFTR) regulates endothelial actin cytoskeleton dynamics and cellular alignment in response to flow. Human lung microvascular endothelial cells (HLMVEC) were cultured with either the CFTR inhibitor GlyH-101 (20 µM) or CFTRinh-172 (20 µM), tumor necrosis factor (TNF)-α (10 ng/ml) or a vehicle control (0.1% dimethyl sulfoxide) during 24 and 48 h of exposure to shear stress (11.1 dynes/cm2 ) or under static control conditions. Cellular morphology and filamentous actin (F-actin) were assessed using immunocytochemistry. [Nitrite] and endothelin-1 ([ET-1]) were determined in cell culture supernatant by ozone-based chemiluminescence and ELISA, respectively. Treatment of HLMVECs with both CFTR inhibitors prevented alignment of HLMVEC in the direction of flow after 24 and 48 h of shear stress, compared to vehicle control (both p < 0.05). Treatment with TNF-α significantly increased total F-actin after 24 h versus control (p < 0.05), an effect that was independent of shear stress. GlyH-101 significantly increased F-actin after 24 h of shear stress versus control (p < 0.05), with a significant (p < 0.05) reduction in cortical F-actin under both static and flow conditions. Shear stress decreased [ET-1] after 24 h (p < 0.05) and increased [nitrite] after 48 h (p < 0.05), but neither [nitrite] nor [ET-1] was affected by GlyH-101 (p > 0.05). CFTR appears to limit cytosolic actin polymerization, while maintaining a cortical rim actin distribution that is important for maintaining barrier integrity and promoting alignment with flow, without effects on endothelial nitrite or ET-1 production.

Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) in Human Lung Microvascular Endothelial Cells Controls Oxidative Stress, Reactive Oxygen-Mediated Cell Signaling and Inflammatory Responses.

BACKGROUND: Perturbation of endothelial function in people with cystic fibrosis (CF) has been reported, which may be associated with endothelial cell expression of the cystic fibrosis transmembrane conductance regulator (CFTR). Previous reports indicate that CFTR activity upregulates endothelial barrier function, endothelial nitric oxide synthase (eNOS) expression and NO release, while limiting interleukin-8 (IL-8) release, in human umbilical vein endothelial cells (HUVECs) in cell culture. In view of reported microvascular dysfunction in people with CF we investigated the role of CFTR expression and activity in the regulation of oxidative stress, cell signaling and inflammation in human lung microvascular endothelial cells (HLMVECs) in cell culture. METHODS: HLMVECs were cultured in the absence and presence of the CFTR inhibitor GlyH-101 and CFTR siRNA. CFTR expression was analyzed using qRT-PCR, immunocytochemistry (IHC) and western blot, and function by membrane potential assay. IL-8 expression was analyzed using qRT-PCR and ELISA. Nrf2 expression, and NF-κB and AP-1 activation were determined using IHC and western blot. The role of the epidermal growth factor receptor (EGFR) in CFTR signaling was investigated using the EGFR tyrosine kinase inhibitor AG1478. Oxidative stress was measured as intracellular ROS and hydrogen peroxide (H2O2) concentration. VEGF and SOD-2 were measured in culture supernatants by ELISA. RESULTS: HLMVECs express low levels of CFTR that increase following inhibition of CFTR activity. Inhibition of CFTR, significantly increased intracellular ROS and H2O2 levels over 30 min and significantly decreased Nrf2 expression by 70% while increasing SOD-2 expression over 24 h. CFTR siRNA significantly increased constitutive expression of IL-8 by HLMVECs. CFTR inhibition activated the AP-1 pathway and increased IL-8 expression, without effect on NF-κB activity. Conversely, TNF-α activated the NF-κB pathway and increased IL-8 expression. The effects of TNF-α and GlyH-101 on IL-8 expression were additive and inhibited by AG1478. Inhibition of both CFTR and EGFR in HLMVECs significantly increased VEGF expression. The antioxidant N-acetyl cysteine significantly reduced ROS production and the increase in IL-8 and VEGF expression following CFTR inhibition. CONCLUSION: Functional endothelial CFTR limits oxidative stress and contributes to the normal anti-inflammatory state of HLMVECs. Therapeutic strategies to restore endothelial CFTR function in CF are warranted.

The implications of dysglycaemia on aerobic exercise and ventilatory function in cystic fibrosis.

BACKGROUND: The development of cystic fibrosis (CF)-related diabetes (CFRD) in paediatric groups is associated with a reduced aerobic fitness. However, this has yet to be investigated in adults with more severe lung disease. METHODS: Cardiopulmonary exercise and glycaemic control tests were retrospectively analysed in 46 adults with CF (age: 26.9 y [range: 16.3-66.5 y]; forced expiratory volume in 1s: 65.3% [range: 26.8-105.7%]; 26 males), diagnosed with CFRD (n = 19), impaired glucose tolerance (IGT; n = 8) or normal glucose tolerance (NGT; n = 19). RESULTS: Maximal oxygen uptake (V˙O2max) was reduced in adults with IGT and CFRD compared to their age- and gender-matched counterparts with NGT (p < 0.05); however, there was no difference when lung function was included as a covariate (all p > 0.05). V˙O2max was greater in adults who experienced post-reactive hypoglycaemia vs. NGT without hypoglycaemia (p < 0.05). The frequency of ventilatory limitation (84%, 63% and 37%, respectively; p < 0.05) but not ventilation-perfusion mismatch (42%, 38% and 16%, respectively; p > 0.05), was greater with CFRD and IGT vs. NGT. There was also no difference in arterial oxygen saturation changes between groups (p > 0.05). Gender and body mass index were significant predictors of V˙O2max (adjusted R2 = 0.37, p < 0.01), but glycaemic control did not explain additional variance (p > 0.05). CONCLUSIONS: Adults with CF-related dysglycaemia had a reduced V˙O2max compared to age- and gender-matched counterparts, due to a greater degree of CF lung disease in these populations.

Circulating biomarkers of antioxidant status and oxidative stress in people with cystic fibrosis: A systematic review and meta-analysis.

INTRODUCTION: Oxidative stress may play an important role in the pathophysiology of cystic fibrosis (CF). This review aimed to quantify CF-related redox imbalances. METHODS: Systematic searches of the Medline, CINAHL, CENTRAL and PsycINFO databases were conducted. Mean content of blood biomarkers from people with clinically-stable CF and non-CF controls were used to calculate the standardized mean difference (SMD) and 95% confidence intervals (95% CI). RESULTS: Forty-nine studies were eligible for this review including a total of 1792 people with CF and 1675 controls. Meta-analysis revealed that protein carbonyls (SMD: 1.13, 95% CI: 0.48 to 1.77), total F2-isoprostane 8-iso-prostaglandin F2α (SMD: 0.64, 95% CI: 0.23 to 1.05) and malondialdehyde (SMD: 1.34, 95% CI: 0.30 to 2.39) were significantly higher, and vitamins A (SMD: -0.66, 95% CI -1.14 to -0.17) and E (SMD: -0.74, 95% CI: -1.28 to -0.20), ß-carotene (SMD: -1.80, 95% CI: -2.92 to -0.67), lutein (SMD: -1.52, 95% CI: -1.83 to -1.20) and albumin (SMD: -0.98, 95% CI: -1.68 to -0.27) were significantly lower in the plasma or serum of people with CF versus controls. CONCLUSIONS: This systematic review and meta-analysis found good evidence for reduced antioxidant capacity and elevated oxidative stress in people with clinically-stable CF.

Cardiopulmonary exercise testing with supramaximal verification produces a safe and valid assessment of V̇o2max in people with cystic fibrosis: a retrospective analysis.

The validity and safety of using supramaximal verification (Smax) to confirm a maximal effort during cardiopulmonary exercise testing (CPET) in people with cystic fibrosis (CF) and/or those with severe disease has been questioned. Therefore, this study aimed to investigate these concerns in children, adolescents, and adults with mild-to-severe CF lung disease. Retrospective analysis of 17 pediatric and 28 adult participants with CF [age range: 9.2-62.9 y; forced expiratory volume in 1 s: 66.7% (range: 29.9%-102.3%); 30 men] who completed a routine ramp-incremental cycling test to determine peak oxygen uptake (V̇o2peak) was studied. Maximal oxygen uptake (V̇o2max) was subsequently confirmed by Smax at 110% of peak power output. All participants satisfied the criteria to verify a maximal effort during CPET. However, Smax-V̇o2peak exceeded ramp-V̇o2peak in 3/14 (21.4%) of pediatric and 6/28 (21.4%) adult exercise tests. A valid measurement of V̇o2max was attained in 85.7% of pediatric and 96.4% of adult exercise tests, as Smax-V̇o2peak did not exceed ramp-V̇o2peak by >9%. Adults ( n = 9) experienced a ≥5% reduction in arterial O2 saturation during CPET, 4 during both the ramp and Smax, 3 during only the ramp, and 2 during only Smax. Smax did not significantly worsen perceived breathing effort, chest tightness, throat narrowing, or exertion compared with ramp-incremental testing. Given the clinical importance of aerobic fitness in people with CF, incorporating Smax is recommended to provide a safe and valid measure of V̇o2max in children, adolescents, and adults who span the spectrum of CF disease severity. NEW & NOTEWORTHY Incorporating supramaximal verification into cardiopulmonary exercise testing protocols did not increase the frequency of adverse events or perceived discomfort versus a single-phase incremental exercise test in people with mild-to-severe cystic fibrosis. Furthermore, a valid measure of maximal oxygen uptake (V̇o2max) was obtained from 85.7% of pediatric and 96.4% of adult exercise tests, whereas peak oxygen uptake underestimated aerobic fitness in comparison with V̇o2max in 21.4% of cases (by up to 24.4%).