The impact of lifestyle, age, and sex on systemic and airway inflammation and oxidative stress

Doctor of PhilosophyDepartment of KinesiologyCraig A. HarmsThe overall aim of this dissertation was to determine the impact of lifestyle (i.e. habitual and acute physical activity and diet), age, and sex on systemic and airway inflammation and oxidative stress. In study 1 (Chapter 2) we examined the impact of habitual physical activity level on the post-prandial airway inflammatory response following an acute bout of moderate intensity exercise. Results indicated that the mean exhaled nitric oxide (eNO; marker of airway inflammation) response increased for all groups at two hours post high-fat meal (HFM) (~6%) and returned to baseline by four hours post-HFM. However, there was a varying eNO response from baseline to four hours in the group that exercised in the post-prandial period compared to the group that remained sedentary. These findings suggest airway inflammation occurs after a HFM when exercise is performed in the post-prandial period, regardless of habitual physical activity level. In study 2 (Chapter 3) we investigated the post-prandial oxidative stress response to meals of varying calories and fat. Specifically, we assessed the post-prandial airway and systemic 8-isoprostane (a marker of oxidative stress) responses to meals with moderate-fat (8.5 kcal/kg of bodyweight) and high-fat content (17 kcal/kg of bodyweight) from baseline to six hours post-meal in a randomized crossover design. This study revealed that systemic 8-isoprostane increased from baseline to six hours post-meal (38.3%), but there was no difference between the moderate-fat meal (MFM) and HFM conditions. There were no changes in airway 8-isoprostane from baseline to six hours post-MFM or HFM, or between the MFM and HFM conditions. Lastly, in study 3 (Chapter 4), we were interested in examining 8-isoprostane responses in older adults, since 8-isoprostane has been reported to increase with age. Previous research also suggests that older women (OW) and older men (OM) have differences with regard to prevalence and severity of late-onset asthma. In this study, we sought to determine whether the airway 8-isoprostane response to a strenuous bout of exercise was different in OW compared to OM. A secondary aim was to determine whether post-exercise 8-isoprostane generation was correlated with decrements in lung function. Our results showed that the generation of 8-isoprostane from pre- to post-exercise increased ~74±77% in OW and decreased ~12±50% in OM. The decrease in 8-isoprostane generation was not correlated with improvements in lung function from pre- to post-exercise. These findings collectively contribute to the literature by enhancing our understanding of the impact of lifestyle factors, age and sex on modifying and potentially mitigating the risk of developing chronic diseases

Household Air Pollution Exposure and Influence of Lifestyle on Respiratory Health and Lung Function in Belizean Adults and Children: A Field Study

Citation: Kurti, S. P., Kurti, A. N., Emerson, S. R., Rosenkranz, R. R., Smith, J. R., Harms, C. A., & Rosenkranz, S. K. (2016). Household Air Pollution Exposure and Influence of Lifestyle on Respiratory Health and Lung Function in Belizean Adults and Children: A Field Study. International Journal of Environmental Research and Public Health, 13(7), 12. doi:10.3390/ijerph13070643Household air pollution (HAP) contributes to the global burden of disease. Our primary purpose was to determine whether HAP exposure was associated with reduced lung function and respiratory and non-respiratory symptoms in Belizean adults and children. Our secondary purpose was to investigate whether lifestyle (physical activity (PA) and fruit and vegetable consumption (FV)) is associated with reported symptoms. Belizean adults (n = 67, 19 Male) and children (n = 23, 6 Male) from San Ignacio Belize and surrounding areas participated in this cross-sectional study. Data collection took place at free walk-in clinics. Investigators performed initial screenings and administered questionnaires on (1) sources of HAP exposure; (2) reported respiratory and non-respiratory symptoms and (3) validated lifestyle questionnaires. Participants then performed pulmonary function tests (PFTs) and exhaled breath carbon monoxide (CO). There were no significant associations between HAP exposure and pulmonary function in adults. Increased exhaled CO was associated with a significantly lower forced expiratory volume in 1-s divided by forced vital capacity (FEV1/FVC) in children. Exposed adults experienced headaches, burning eyes, wheezing and phlegm production more frequently than unexposed adults. Adults who met PA guidelines were less likely to experience tightness and pressure in the chest compared to those not meeting guidelines. In conclusion, adults exposed to HAP experienced greater respiratory and non-respiratory symptoms, which may be attenuated by lifestyle modifications

Summation of blood glucose and TAG to characterise the 'metabolic load index'

Citation: Emerson, S. R., Haub, M. D., Teeman, C. S., Kurti, S. P., & Rosenkranz, S. K. (2016). Summation of blood glucose and TAG to characterise the 'metabolic load index'. British Journal of Nutrition, 116(9), 1553-1563. doi:10.1017/s0007114516003585Research points to postprandial glucose and TAG measures as preferable assessments of cardiovascular risk as compared with fasting values. Although elevated postprandial glycaemic and lipaemic responses are thought to substantially increase chronic disease risk, postprandial glycaemia and lipaemia have historically only been considered separately. However, carbohydrates and fats can generally 'compete' for clearance from the stomach, small intestine, bloodstream and within the peripheral cell. Further, there are previous data demonstrating that the addition of carbohydrate to a high-fat meal blunts the postprandial lipaemic response, and the addition of fat to a high-carbohydrate meal blunts the postprandial glycaemic response. Thus, postprandial glycaemia and lipaemia are interrelated. The purpose of this brief review is 2-fold: first, to review the current evidence implicating postprandial glycaemia and lipaemia in chronic disease risk, and, second, to examine the possible utility of a single postprandial glycaemic and lipaemic summative value, which will be referred to as the metabolic load index. The potential benefits of the metabolic load index extend to the clinician, patient and researcher

The potential link between sugar-sweetened beverage consumption and post-exercise airway narrowing across puberty: a longitudinal cohort study

Citation: Emerson, S. R., Rosenkranz, S. K., Rosenkranz, R. R., Kurti, S. P., & Harms, C. A. (2016). The potential link between sugar-sweetened beverage consumption and post-exercise airway narrowing across puberty: a longitudinal cohort study. Public Health Nutrition, 19(13), 2435-2440. doi:10.1017/s1368980015003109Objective The prevalence of asthma is rising, presenting serious public health challenges. Recent data suggest that sugar-sweetened beverage (SSB) consumption plays a role in asthma aetiology. The purpose of the present study was to determine whether SSB consumption is linked to post-exercise airway narrowing (predictor of asthma development) across puberty. Design Participants completed pulmonary function tests, physical activity and dietary habit questionnaires, and an exercise test to exhaustion. Setting Community in Manhattan, Kansas, USA. Subjects We recruited ten boys and ten girls from an original cohort of forty participants tested in our laboratory approximately 5 years prior. Participants were aged 97 (sd 09) years at baseline and 147 (sd 09) years at follow-up. Results Pre-puberty, boys consumed 68 (sd 48) servings/week and girls consumed 69 (sd 37) servings/week, while post-puberty boys consumed 115 (sd 53) servings/week and girls consumed 77 (sd 43) servings/week. Using Pearson correlation, SSB consumption was not significantly related to post-exercise airway narrowing at pre-puberty (r=-035, P=0130). In linear regression analyses, SSB consumption was significantly related to post-exercise airway narrowing post-puberty before (standardized =-060, P=0005) but not after (standardized =-033, P=0211) adjustment for confounders. Change in SSB consumption from pre- to post-puberty was significantly associated with post-exercise airway narrowing post-puberty (r=-061, P=0010) and change in post-exercise airway narrowing from pre- to post-puberty (r=-045, P=0048) when assessed via Pearson correlations. Conclusions These findings suggest a possible link between SSB consumption and asthma development during maturation. Reduced SSB intake may be a possible public health avenue for blunting rising asthma prevalence

Effects of thirty and sixty minutes of moderate-intensity aerobic exercise on postprandial lipemia and inflammation in overweight men: a randomized cross-over study

Citation: Emerson, S. R., Kurti, S. P., Snyder, B. S., Sitaraman, K., Haub, M. D., & Rosenkranz, S. K. (2016). Effects of thirty and sixty minutes of moderate-intensity aerobic exercise on postprandial lipemia and inflammation in overweight men: a randomized cross-over study. Journal of the International Society of Sports Nutrition, 13, 12. doi:10.1186/s12970-016-0137-8Background: The transient rise in blood lipids following a high-fat meal (HFM), known as postprandial lipemia, is linked to systemic inflammation and cardiovascular disease, but can be blunted by exercise. However, minimal research has investigated the effects of realistic exercise bouts on postprandial lipemia and inflammation in at-risk individuals. The purpose of this study was to assess the effects of moderate-intensity aerobic exercise lasting 30 or 60 min performed the evening before a HFM, on postprandial lipemia and inflammation in overweight, insufficiently active men. Methods: In this randomized-crossover study, twelve participants remained sedentary (CON), or performed a brisk walk on a treadmill at 60 % VO2peak for either 30 min (EX-30) or 60 min (EX-60), after which they consumed a small snack (270 kcal) to partially replace exercise energy expenditure. Following a 12-h overnight fast, participants consumed a standard HFM (1 g fat/kg; 1 g CHO/kg; 1117.8 +/- 117.0 kcal). Blood draws were performed at baseline (pre-HFM) and 1, 2, 4, 6, and 8 h post-HFM to assess glucose, insulin, lipids, and systemic inflammation. Results: There were no significant differences (p > 0.05) in fasting triglycerides between EX-60 (118.7 +/- 68.3 mg/dL), CON (134.8 +/- 66.2 mg/dL) or EX-30 (135.5 +/- 85.4 mg/dL). There were no differences in peak, time-to-peak, total or incremental area-under-the-curve between trials for triglyceride response (p > 0.05). There was no significant main effect of time (p > 0.05) in IL-1ra, IL-4, IL-5, IL-6, IL-10 or TNF-alpha from baseline to 8 h post-HFM in any trial. Conclusions: In summary, we found that in overweight, insufficiently active men, neither 30 nor 60 min of moderate-intensity exercise performed 12 h prior to a HFM attenuated postprandial lipemia or inflammation, which could potentially be explained by the partial caloric replacement of exercise energy expenditure

Does moderate intensity exercise attenuate the postprandial lipemic and airway inflammatory response to a high-fat meal?

Citation: Stephanie P. Kurti, Sara K. Rosenkranz, Morton Levitt, et al., “Does Moderate Intensity Exercise Attenuate the Postprandial Lipemic and Airway Inflammatory Response to a High-Fat Meal?,” BioMed Research International, vol. 2015, Article ID 647952, 10 pages, 2015. doi:10.1155/2015/647952We investigated whether an acute bout of moderate intensity exercise in the postprandial period attenuates the triglyceride and airway inflammatory response to a high-fat meal (HFM) compared to remaining inactive in the postprandial period. Seventeen (11 M/6 F) physically active (≥150 min/week of moderate-vigorous physical activity (MVPA)) subjects were randomly assigned to an exercise (EX; 60% VO[subscript 2peak]) or sedentary (CON) condition after a HFM (10 kcal/kg, 63% fat). Blood analytes and airway inflammation via exhaled nitric oxide (eNO) were measured at baseline, and 2 and 4 hours after HFM. Airway inflammation was assessed with induced sputum and cell differentials at baseline and 4 hours after HFM. Triglycerides doubled in the postprandial period (~113 ± 18%, P < 0.05 ), but the increase did not differ between EX and CON. Percentage of neutrophils was increased 4 hours after HFM (~17%), but the increase did not differ between EX and CON. Exhaled nitric oxide changed nonlinearly from baseline to 2 and 4 hours after HFM (P < 0.05, ƞ² = 0.36) . Our findings suggest that, in active individuals, an acute bout of moderate intensity exercise does not attenuate the triglyceride or airway inflammatory response to a high-fat meal

Lipemic and Airway Inflammatory Response to a High-Fat Meal?

We investigated whether an acute bout of moderate intensity exercise in the postprandial period attenuates the triglyceride and airway inflammatory response to a high-fat meal (HFM) compared to remaining inactive in the postprandial period. Seventeen (11 M/6 F) physically active (≥150 min/week of moderate-vigorous physical activity (MVPA)) subjects were randomly assigned to an exercise (EX; 60% VO 2peak ) or sedentary (CON) condition after a HFM (10 kcal/kg, 63% fat). Blood analytes and airway inflammation via exhaled nitric oxide (eNO) were measured at baseline, and 2 and 4 hours after HFM. Airway inflammation was assessed with induced sputum and cell differentials at baseline and 4 hours after HFM. Triglycerides doubled in the postprandial period (∼113 ± 18%, &lt; 0.05), but the increase did not differ between EX and CON. Percentage of neutrophils was increased 4 hours after HFM (∼17%), but the increase did not differ between EX and CON. Exhaled nitric oxide changed nonlinearly from baseline to 2 and 4 hours after HFM ( &lt; 0.05, 2 = 0.36). Our findings suggest that, in active individuals, an acute bout of moderate intensity exercise does not attenuate the triglyceride or airway inflammatory response to a high-fat meal

RESPIRATORY MUSCLE FATIGUE AND REDUCED OPERATING LUNG VOLUMES WITH PROLONGED LOAD CARRIAGE IN HYPOXIA

BACKGROUND: Prior research indicates that thoracic load carriage induces shallower breathing patterns and respiratory muscle fatigue in normoxic conditions. The purpose of this study was to determine whether load carriage compromises the compensatory ventilatory responses to hypoxic exposure. METHODS: Pulmonary function (i.e., forced vital capacity [FVC], forced expiratory volume in 1 sec [FEV1], and peak flow [PEF]), respiratory muscle fatigue (i.e., maximal inspiratory [MIP] and expiratory [MEP] pressure), dyspnea, and ventilatory responses (i.e., operating lung volumes and ventilation [VE]) to prolonged exercise were assessed in healthy male subjects (n=12) under 3 conditions: unloaded normoxic (FiO2=20.93%; UN), unloaded hypoxic (equivalent to ~3,650m; FiO2=~13.0%; UH), and loaded hypoxic (~30 kg pack; FiO2=~13.0%; LH). Exercise consisted of 45 min uphill (8%) walking at speeds individually customized to elicit an equivalent relative intensity in hypoxia (64.0±2.6%VO2max) and absolute VO2 across conditions (2.0±0.2 L/min). One-way ANOVAs and t-tests were employed to analyze pulmonary function and respiratory muscle fatigue (pre- vs. post-exercise), respectively. Exercise data were analyzed via two-way repeated measures ANOVA with post hoc one-way ANOVA tests to identify differences in the case of significant interactions (α=0.05). RESULTS: FVC (-7.8-8.5%), FEV1 (-9.0-10.2%), and PEF (-8.3-11.0%) were reduced with LH relative to the unloaded conditions (p\u3c0.05). Additionally, MIP (-12.2±9.7%) and MEP (-10.2±11.2%) were reduced following exercise with LH (p\u3c0.05) but were unchanged with UN and UH. In both hypoxic conditions relative to normoxia, VE and dyspnea were increased throughout exercise (p \u3c 0.05). However, with LH vs. UH, VE and dyspnea were further increased starting at 30 min (p \u3c 0.05), which coincided with increases in deadspace VE (i.e., starting at 20 min; p \u3c 0.05). In addition, breathing frequency and tidal volume were increased and decreased (p \u3c 0.05), respectively, throughout exercise due to reductions in end inspiratory lung volumes (p \u3c 0.05). CONCLUSIONS: Load carriage reduces respiratory efficiency and increases breathing discomfort during exercise in hypoxia. This may compromise health and performance during occupational tasks in high altitude environments. GRANT OR FUNDING INFORMATION: This study was funded by the Jackson-Hope New Directions in Research grant