Exercise training effects on natural killer cells: a preliminary proteomics and systems biology approach.

BACKGROUND: Regular exercise, particularly moderate-intensity continuous training (MICT), can improve immune function. Natural killer (NK) cells, a subset of lymphocytes that react to infections, are the most responsive innate immune cells to exercise, but the mechanisms underlying this are poorly understood. A type of exercise training that is gaining popularity in recent years is high-intensity interval training (HIIT), but how it affects NK cells is largely unknown. In fact, intense exercise has been traditionally viewed as a potential stressor to immune homeostasis. The purpose of this study was to determine in healthy, previously untrained adults (N=8 [3 male; 40±6 years]) the effects of an intervention consisting of 4-week MICT followed by 4-week HIIT on NK cells as compared with a pre-training (baseline) state. METHODS: Participants were studied at three time points: baseline, mid-intervention (after MICT), and post-intervention (after HIIT). Main assessments included cytotoxicity assays, flow-cytometry analysis of NK cell surface markers, and interrogation of the cellular proteome using a systems biology approach. RESULTS: A significant time effect was found for NK cell cytotoxicity (p<0.001), which was increased ~10-fold at both midand post-intervention versus baseline. No significant intervention effect was found for NK surface receptor expression, except for CXCR3 determined as mean fluorescence intensity (p=0.044, although with no significant differences in post hoc pairwise comparisons). The proteins showing a higher differential expression (Log2 fold-change > 10 and false discovery rate [FDR] q-value < 0.001) were COP9 signalosome subunit 3 (COPS3), DnaJ heat shock protein family member B11 (DNAJB11), histidyl-TRNA synthetase 1 (HARS), NIMA related kinase 9 (NEK9), nucleoporin 88 (NUP88), phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1), regulator of chromosome condensation 2 (RCC2), TAO kinase 3 (TAOK3), transducin beta like 2 (TBL2), and ring finger protein 40 (RNF40). All were upregulated at mid-intervention compared with baseline, with the exception of HARS, which was downregulated. Four enriched pathways (FDR p<25%) were found: two related to transmembrane transport and cellular composition (downregulated at mid-intervention vs baseline), and two related to oxidation- reduction reactions (regulated at post-intervention versus baseline). CONCLUSION: A progressive exercise intervention of MICT followed by HIIT induces a remarkable improvement in NK function compared with the untrained state, although at the mechanistic level the pathways involved seem to differ over time during the intervention.

Objectively assessed physical activity levels in Spanish cancer survivors.

PURPOSE/OBJECTIVES: To objectively assess physical activity (PA) levels in a cohort of Spanish cancer survivors. DESIGN: Descriptive, cross-sectional. SETTING: The Hospital Universitario de Fuenlabrada and two healthcare centers in Madrid, Spain. SAMPLE: 204 cancer survivors and 115 adults with no history of cancer. METHODS: Participants wore a triaxial accelerometer for seven or more consecutive days to assess PA levels. Body mass index (BMI), indirect indicators of adiposity (waist circumference, waist-to-hip ratio), and cardiorespiratory fitness also were determined. MAIN RESEARCH VARIABLES: Light, moderate, vigorous, and total PA (sum of the former). FINDINGS: Most (94%) of the cancer survivors met international recommendations for moderate PA, but very few (3%) fulfilled those (75 minutes or more per week) for vigorous PA. Except for lower total (minute per day, p=0.048) and vigorous PA levels (p<0.001 for both minute per day and minute per week) recorded in the cancer survivors group, no between-group differences were detected (p>0.05). A high percentage of the survivors (33%) were obese (BMI greater than 30 kg/m2), and many also showed poor cardiorespiratory fitness (45% were below the 8 metabolic equivalent threshold). CONCLUSIONS: Although cancer survivors overall met international PA recommendations for a healthy lifestyle, their BMI and cardiorespiratory profiles were not within the healthy range. IMPLICATIONS FOR NURSING: Cancer survivors need to be informed about healthy lifestyle habits and should be regularly monitored.