Effects of a Lactobacillus salivarius probiotic intervention on infection, cold symptom duration and severity, and mucosal immunity in endurance athletes

The purpose of this study was to examine the effects of a probiotic supplement during 4 mo of spring training in men and women engaged in endurance-based physical activities on incidence of upper respiratory tract infections (URTI) and mucosal immune markers. Sixty-six highly active individuals were randomized to probiotic (n = 33) or placebo (n = 33) groups and, under double-blind procedures, received probiotic (PRO: Lactobacillus salivarius, 2 × 1010 bacterium colony-forming units) or placebo (PLA) daily for 16 wk. Resting blood and saliva samples were collected at baseline and after 8 and 16 wk. Weekly training and illness logs were kept. Fifty-four subjects completed the study (n = 27 PRO, n = 27 PLA). The proportion of subjects on PRO who experienced 1 or more wk with URTI symptoms was not different from that of those on PLA (PRO .58, PLA .59; p = .947). The number of URTI episodes was similar in the 2 groups (PRO 1.6 ± 0.3, PLA 1.4 ± 0.3; p = .710). Severity and duration of symptoms were not significantly different between treatments. Blood leukocyte, neutrophil, monocyte, and lymphocyte counts; saliva IgA; and lysozyme concentrations did not change over the course of the study and were not different on PRO compared with PLA. Regular ingestion of L. salivarius does not appear to be beneficial in reducing the frequency of URTI in an athletic cohort and does not affect blood leukocyte counts or levels of salivary antimicrobial proteins during a spring period of training and competition

Supplementary information files for Sedentary behaviour, but not moderate-to-vigorous physical activity, is associated with respiratory responses to acute psychological stress

Supplementary files for article Sedentary behaviour, but not moderate-to-vigorous physical activity, is associated with respiratory responses to acute psychological stress Background Acute psychological stress induces respiratory responses, and stress-induced respiratory changes can be used to non-invasively reflect metabolic regulation. Respiratory and cardiovascular responses to stress are both driven by sympathetic mechanisms. Higher volumes of sedentary behaviour and lower volumes of physical activity are associated with elevated sympathetic tone and larger cardiovascular responses to stress. The aim of this study was to test whether these associations translate to measures of respiratory stress reactivity. Methods Daily hours of sedentary behaviour (thigh-mounted activPAL) and moderate-to-vigorous physical activity (MVPA; wrist-mounted ActiGraph) were assessed across seven days. Breath-by-breath respiratory (e.g., breathing frequency [BF], end-tidal carbon dioxide partial pressure [PetCO2], carbon dioxide output [V̇CO2] and respiratory exchange ratio [RER]) responses to an 8-min Paced Auditory Serial Addition Test were then measured using a Cortex MetaLyzer3B. Results Healthy participants (N = 61, mean age ± SD = 25.7 ± 8.9 years) recorded high volumes of sedentary behaviour (9.96 ± 1.48 hours/day) and MVPA (1.70 ± 0.71 hours/day). In adjusted models (with the inclusion of sedentary behaviour, MVPA, and other a priori selected covariates) hours of daily sedentary behaviour were associated with baseline to stress changes in BF (Β = 0.695, 95% CI = 0.281 — 1.109, p =.014), VT (Β = -0.042, 95% CI = -0.058 — -0.026, p =.014), PetCO2 (Β = -0.537, 95% CI = -0.829 — -0.245, p =.014), V̇CO2 (Β = -0.008, 95% CI = -0.014 — -0.003, p =.030), and RER (Β = -0.013, 95% CI = -0.021 — -0.005, p =.022). Daily hours of MVPA were not linked with respiratory responses to stress. Discussion Sedentary behaviour, but not MVPA, is associated with respiratory stress reactivity. Future work should untangle the underlying mechanisms of these findings and explore the consequences for cardiometabolic disease.</p

Perceptions and Experiences of High-Intensity Interval Training in Kidney Transplant Recipients: A Big HIIT?

High-intensity interval training (HIIT) is considered a novel and time-efficient method to reduce cardiovascular disease risk, a leading cause of mortality in kidney transplant recipients. However, research in this population is severely limited. The aim of this study was to understand kidney transplant recipients' perceptions and experiences of HIIT and their readiness to participate in HIIT. Individual, semi-structured interviews were conducted in adults with a kidney transplant (n = 13; 53±13 years). Interviews were audiorecorded, transcribed verbatim, and subjected to framework analysis. Overall, participants had a good knowledge of HIIT and were open to participation. Acknowledgment of the superior benefits to cardiovascular, mental, and general health, as well as the lower time commitment, were all motivators for participation. There were some heightened concerns around damaging the kidney and 'knowing your limits. Personalization, physician's approval, and supervision were all important factors in participation. This study provides evidence that HIIT would be, in principle, largely accepted by recipients of a kidney transplant. However, several considerations are also identified in the present study, which would be essential to the success of any future efficacy trial or rehabilitation program.</p

MO605: Exploring the Relationship Between Cardiorespiratory Fitness and Cardiovascular Risk in Kidney Transplant Recipients

BACKGROUND AND AIMS Cardiovascular disease (CVD) remains a leading cause of mortality for kidney transplant recipients (KTR). Traditional risk factors include smoking, obesity, hypertension and hyperlipidemia. Nontraditional risk factors include creatinine levels, previous transplants and total time on renal replacement therapy. High levels of physical inactivity have long been known to link with poor cardiovascular outcomes. The first United Kingdom Clinical Practice Guidelines for Exercise and Lifestyle in Chronic Kidney Disease recommend that KTRs aim for 150 min of moderate to vigorous physical activity a week (or 75 min vigorous physical activity) plus two strength training sessions in line with current World Health Organisation recommendations for the general population. However, evidence suggests that only 27% of KTRs are sufficiently active for health. We aimed to explore the relationship between cardiorespiratory fitness and the 7-year risk of major adverse cardiac events (MACE) and 7-year risk of mortality in KTRs. METHOD 49 KTRs (31 male; mean [±SD]; 59 [±19] eGFR mL/min/1.73 m2; age 49 [±14] years) completed a continuous ramp cardiopulmonary exercise test (1W increase every 4 s) to volitional exhaustion on a cycle ergometer. The cardiovascular risk calculator for renal transplant recipients (CRCRTR-MACE) was used to calculate 7-year risk of MACE and 7-year risk of mortality. Cardiorespiratory fitness categories were defined in accordance with the American College of Sports Medicine guidelines. Data were analyzed using hierarchical multiple regression adjusting for gender. RESULTS 84% of participants were classified as having ‘poor’ or ‘very poor’ cardiorespiratory fitness (VO2; ml/kg/min). Cardiorespiratory fitness was a significant predictor of 7-year risk of MACE after adjusting for gender (F(2, 40) = 10.64, P CONCLUSION This exploratory analysis shows that cardiorespiratory fitness explains 31.5% and 26.3% of the variance in the 7-year risk of MACE and the 7-year risk of mortality, respectively. Various interventions have been shown to improve cardiorespiratory fitness in KRTs. Improving levels of physical activity and subsequently cardiovascular fitness provide a low cost strategy to partially attenuate some of widespread impact of CVD-related morbidity and mortality. These results highlight the importance of incorporating physical activity as part of post-transplant care.</p

Microparticles and exercise in clinical populations

Microparticles (MPs) are shed membrane vesicles released from a variety of cell types in response to cellular activation or apoptosis. They are elevated in a wide variety of disease states and have been previously measured to assess both disease activity and severity. However, recent research suggests that they also possess bioeffector functions, including but not limited to promoting coagulation and thrombosis, inducing endothelial dysfunction, increasing pro‐inflammatory cytokine release and driving angiogenesis, thereby increasing cardiovascular risk. Current evidence suggests that exercise may reduce both the number and pathophysiological potential of circulating MPs, making them an attractive therapeutic target. However, the existing body of literature is largely comprised of in vitro or animal studies and thus drawing meaningful conclusions with regards to health and disease remains difficult. In this review, we highlight the role of microparticles in disease, comment on the use of exercise and dietary manipulation as a therapeutic strategy, and suggest future research directions that would serve to address some of the limitations present in the research to date

Effect of high intensity interval training and moderate intensity continuous training on lymphoid, myeloid and inflammatory cells in kidney transplant recipients

Kidney transplantations are seen to be a double-edge sword. Transplantations help to partially restore renal function, however there are a number of health-related co-morbidities associated with transplantation. Cardiovascular disease (CVD), malignancy and infections all limit patient and graft survival. Immunosuppressive medications alter innate and adaptive immunity and can result in immune dysfunction. Over suppression of the immune system can result in infections whereas under suppression can result in graft rejection. Exercise is a known therapeutic intervention with many physiological benefits. Its effects on immune function are not well characterised and may include both positive and negative influences depending on the type, intensity, and duration of the exercise bout. High intensity interval training (HIIT) has become more popular due to it resulting in improvements to traditional and inflammatory markers of cardiovascular (CV) risk in clinical and non-clinical populations. Though these improvements are similar to those seen with moderate intensity exercise, HIIT requires a shorter overall time commitment, whilst improvements can also be seen even with a reduced exercise volume.The purpose of this study was to explore the physiological and immunological impact of 8-weeks of HIIT and moderate intensity continuous training (MICT) in kidney transplant recipients (KTRs). In addition, the natural variations of immune and inflammatory cells in KTRs and non-CKD controls over a longitudinal period are explored. Newly developed multi-colour flow cytometry methods were devised to identify and characterise immune cell populations.Twenty-six KTRs were randomised into one of two HIIT protocols or MICT: HIIT A (n=8; 4-, 2-, and 1-min intervals; 80-90% V̇O2peak), HIIT B (n=8, 4×4 min intervals; 80-90% V̇O2peak) or MICT (n=8, ~40 min; 50-60% V̇O2peak) for 24 supervised sessions on a stationary bike (approx. 3x/week over 8 ± 2 weeks). Blood samples taken pre-training, mid training, post-training and 3 months later. Novel multi-colour flow cytometric panels were developed to characterise lymphoid and myeloid cell population from peripheral blood mononuclear cells. No changes were observed for circulating immune and inflammatory cells over the 8-week interventions.This feasibility study does not suggest that exercise programmes using HIIT and MICT protocols elicit adverse negative effects on immunity in KTRs. Therefore, such protocols may be immunologically safe for these patients. The inability of the participants to achieve the target exercise intensities may be due to physiological abnormalities in this population which warrants further investigation</div

Feasibility and acceptability of high intensity interval training and moderate intensity continuous training in kidney transplant recipients: The PACE-KD stud

Background Kidney transplant recipients (KTRs) exhibit unique elevated inflammation, impaired immune function, and increased cardiovascular risk. Although exercise reduces cardiovascular risk, there is limited research on this population, particularly surrounding novel high-intensity interval training (HIIT). The purpose of this pilot study was to determine the feasibility and acceptability of HIIT in KTRs. Methods Twenty KTRs (male 14; eGFR 58±19 mL/min/1.73 m2; age 49±11 years) were randomised and completed one of three trials: HIIT A (4-, 2-, and 1-min intervals; 80–90% watts at V̇O2peak), HIITB (4×4 min intervals; 80–90% V̇O2peak) or MICT (~40 min; 50–60% V̇O2peak) for 24 supervised sessions on a stationary bike (approx. 3x/week over 8 weeks) and followed up for 3 months. Feasibility was assessed by recruitment, retention, and intervention acceptability and adherence. Results Twenty participants completed the intervention, and 8 of whom achieved the required intensity based on power output (HIIT A, 0/6 [0%]; HIITB, 3/8 [38%]; MICT, 5/6 [83%]). Participants completed 92% of the 24 sessions with 105 cancelled and rescheduled sessions and an average of 10 weeks to complete the intervention. Pre-intervention versus post-intervention V̇O2peak (mL/kg-1/min-1) was 24.28±4.91 versus 27.06±4.82 in HIITA, 24.65±7.67 versus 27.48±8.23 in HIIT B, and 29.33±9.04 versus 33.05±9.90 in MICT. No adverse events were reported. Conclusions This is the first study to report the feasibility of HIIT in KTRs. Although participants struggled to achieve the required intensity (power), this study highlights the potential that exercise has to reduce cardiovascular risk in KTRs. HIIT and MICT performed on a cycle, with some modification, could be considered safe and feasible in KTRs. Larger scale trials are required to assess the efficacy of HIIT in KTRs and in particular identify the most appropriate intensities, recovery periods, and session duration. Some flexibility in delivery, such as incorporating home-based sessions, may need to be considered to improve recruitment and retention.</p

Perceived barriers and facilitators to exercise in kidney transplant recipients: a qualitative study

BackgroundExercise has the potential to attenuate the high levels of cardiovascular morbidity and mortality present in kidney transplant recipients (KTRs). Despite this, activity levels in KTRs remain low. The aim of this qualitative study was to explore the barriers and facilitators of exercise in KTRs.MethodsThirteen KTRs (eight males; mean ± SD; age 53 ± 13 years; estimated glomerular filtration rate 53 ± 21 ml/min/1.73 m2) were recruited and completed semistructured one-to-one interviews at University Hospitals of Leicester NHS Trust. All KTRs were eligible if their kidney transplant was completed >12 weeks before interview and their consultant considered them to have no major contraindications to exercise. All interviews were audio recorded, transcribed verbatim and subject to framework analysis to identify and report themes.ResultsThemes were organized into personal, behavioural and environmental factors based on social cognitive theory. Facilitators of exercise were largely internal: enjoyment, exercise for general health and health of the transplanted kidney and desire to maintain normality. Social interaction, support and guidance of healthcare professionals and goal setting were perceived as motivational. Harming the kidney, a lack of guidance, self-motivation and accessibility were barriers to exercise.ConclusionThese results provide detailed insight into the development of interventions designed to increase physical activity in KTRs. They provide strong evidence that specific exercise guidelines are required for this population and that the healthcare system could have a key role in supporting KTRs to become more physically active. Interventions need to be multifaceted to appeal to the differing levels of support desired by KTRs.Patient or Public ContributionKTRs were involved in the development of the interview topic guide to ensure all relevant topics were explored.</div

#3030 FEASIBILITY OF HOME-BASED EXERCISE IN KIDNEY TRANSPLANT RECIPIENTS: PARTICIPANT CHARACTERISTICS AND INITIAL RESULTS FROM THE ECSERT TRIAL

Background and Aims Kidney transplant recipients (KTR) are prone to high rates of infection, malignancy and cardiovascular disease. Poor physical fitness and physical inactivity remain pertinent targets to improve post-transplant clinical outcomes. Only 27% of KTR are classified as physically active for health. The ECSERT pilot randomised controlled trial aims to assess the feasibility of delivering a structured, home-based exercise intervention in 50 KTR at increased cardiometabolic risk and evaluated the putative effects on cardiovascular structure and function, cardiorespiratory fitness, physical function, quality of life, metabolic and inflammatory markers. We present interim feasibility data describing engagement with the home-based programme of exercise for all patients who have completed the programme to date. Method Potential KTRs were screened for eligibility and approached by their consultant nephrologist, and if interested, further study details were explained by a researcher. Those who consented to take part were randomised (1:1) to either a 12-week structured home-based exercise programme (INT, n = 22) or 12-week usual care control (CTR, n = 23). Figure 1 outlines the home-based exercise programme. The a priori thresholds for specific feasibility and acceptability criteria are as follows: recruitment success of 20% of eligible participants (≥2 participants per month), adherence (an average of three exercise sessions per week) and attrition (≤30%). Results Ninety patients were approached and 45 (50%) recruited across 22 months of recruitment (currently ongoing). Participant characteristics were: 50±14 years (INT 48±13; CTR 52±15), 21 male (INT 8; CTR 13), eGFR 59±19 ml/min/1.73 m2 (INT 62±19; CTR 58±19), 31 White British (WB) and 14 Asian ethnicity (INT 14 WB, 8 Asian; CNR 17 WB, 6 Asian). Two participants withdrew from the intervention group (1 due to COVID-19 infection, 1 due to recurrent urine infections unrelated to the trial) and one from the control group (lost to follow-up; 7.3% attrition). There were no adverse events reported related to the exercise intervention or trial procedures. Intervention participants (n = 16 completed) recorded an average of 4.5±1.4 exercise sessions per week (aerobic 2.9±1.2; strength 1.6±0.4). Completion of key baseline outcome measures was: cardiac MRI scan 95%, cardiopulmonary exercise test 88%, accelerometry 100%, physical function 100%, body composition 100%, blood sampling 100% and questionnaire packs 97.6%. Conclusion Results suggest engagement with the home-based exercise programme in KTRs is excellent. The study is comfortably exceeding a priori thresholds relating to recruitment, retention and completion suggesting patients are interested in the study and the programme of exercise despite the current evidence showing physical activity levels are low. The groups are well matched and there is encouraging representation of female participants and participants from a non-white background. These initial results support study continuation and further assessment and development of home-based programmes of exercise and activity for KTR.</p

#5045 CARDIORESPIRATORY FITNESS IN KIDNEY TRANSPLANT RECIPIENTS: A CASE-CONTROL STUDY AND INITIAL REVIEW OF THE EFFECTS OF A HOME-BASED EXERCISE PROGRAMME

Background and Aims Kidney transplant recipients (KTRs) have an increased burden of cardiovascular disease (CVD) due to clustering of traditional and non-traditional risk factors. Poor cardiorespiratory fitness (CRF) is linked to higher levels of morbidity and mortality. Cardiorespiratory fitness is a significant predictor of 7-year risk of mortality, with each 1 ml/kg/min increase in VO2 associated with a 1% decrease in risk of mortality.[1] Although KTRs have higher CRF than patients with kidney failure, performance compared to the general population has not been quantified. Neither has the link between CRF and physical function. We assessed differences in CRF between KTRs and healthy volunteers in a case-control study. We then explored relationships between CRF and physical function and possible effects of a 12-week structured home-based exercise programme in KTRs. Method Case-control: 20 KTRs (10 male; age 61.2 ±8.1 years; body mass 84.1 ±19.9 kg) and 20 healthy volunteers (10 male; age 61.9 ±7.7 years; body mass 76.7 ±18.1 kg) completed a continuous ramp cardiopulmonary exercise test (CPET) to volitional exhaustion on a cycle ergometer. CPET variables were compared between groups using independent samples t-tests. Thirteen KTRs (6 male; age 47.8 ±15.9 years; eGFR 64.6 ±19.1 ml/min/1.73 m2), to date, have completed a 12-week structured, combined aerobic and resistance, home-based exercise programme as part of a pilot randomised controlled trial.[2] Bivariate correlations were used to explore the association between cardiorespiratory fitness and physical function measures (sit-to-stand 60 [STS60], timed up and go [TUAG], gait speed [GS] and handgrip strength [HGS]). Paired samples t-tests were used to compare pre- and post-intervention variables. Results Case-control: Cardiorespiratory fitness (VO2 peak) was lower in KTRs (18.4±5.2 mL/kg/min) than in healthy volunteers (24.3 ±5.9 mL/kg/min), a difference of 5.9 mL/kg/min (95% CI, 2.4-9.5), t(38) = 3.35, p Conclusion Cardiorespiratory fitness in KTRs is significantly impaired compared to healthy control subjects. In KTRs, aerobic fitness assessed with VO2 peak correlated with field tests assessing physical function. Initial findings suggest that CRF may improve following a structured, home-based programme of exercise, but these data need confirming in larger studies and will be assessed in the final analysis of this pilot randomised trial.</p