Circulating MicroRNA Responses to Postprandial Lipemia with or without Prior Exercise

Repeated exposure to a high-fat meal triggers inflammation and oxidative stress, contributing to the onset of cardiometabolic diseases. Regular exercise prevents cardiometabolic diseases and a prior bout of acute endurance exercise can counteract the detrimental cardiovascular effects of a subsequent high-fat meal. Circulating microRNAs (ci-miRs) are potential mediators of these vascular effects through regulation of gene expression at the posttranscriptional level. Therefore, we investigated the expression of ci-miRs related to vascular function (miR-21, miR-92a, miR-126, miR-146a, miR-150, miR-155, miR-181b, miR-221, miR-222) in plasma from healthy, recreationally to highly active, Caucasian adult men after a high-fat meal with (EX) and without (CON) a preceding bout of cycling exercise. Ci-miR-155 was the only ci-miR for which there was a significant interaction effect of high-fat meal and exercise (p=0.050). Ci-miR-155 significantly increased in the CON group at two (p=0.007) and four hours (p=0.010) after the high-fat meal test, whereas it significantly increased in the EX group only four hours after the meal (p=0.0004). There were significant main effects of the high-fat meal on ci-miR-21 (p=0.01), ci-miR-126 (p=0.02), ci-miR-146a (p=0.02), ci-miR-181b (p=0.02), and ci-miR-221 (p=0.008). Collectively, our results suggest that prior exercise does not prevent high-fat meal-induced increases in vascular-related ci-miRs.

Changes in circulating microRNA and arterial stiffness following high-intensity interval and moderate intensity continuous exercise

High‐intensity interval (HII) exercise elicits distinct vascular responses compared to a matched dose of moderate intensity continuous (MOD) exercise. However, the acute effects of HII compared to MOD exercise on arterial stiffness are incompletely understood. Circulating microRNAs (ci‐miRs) may contribute to the vascular effects of exercise. We sought to determine exercise intensity‐dependent changes in ci‐miR potentially underlying changes in arterial stiffness. Ten young, healthy men underwent well‐matched, 30‐min HII and MOD exercise bouts. RT‐qPCR was used to determine the levels of seven vascular‐related ci‐miRs in serum obtained immediately before and after exercise. Arterial stiffness measures including carotid to femoral pulse wave velocity (cf‐PWV), carotid arterial compliance and β‐stiffness, and augmentation index (AIx and AIx75) were taken before, 10min after and 60min after exercise. Ci‐miR‐21‐5p, 126‐3p, 126‐5p, 150‐5p, 155‐5p, and 181b‐5p increased after HII exercise (p < .05), while ci‐miR‐150‐5p and 221‐3p increased after MOD exercise (p = .03 and 0.056). One hour after HII exercise, cf‐PWV trended toward being lower compared to baseline (p = .056) and was significantly lower compared to 60min after MOD exercise (p = .04). Carotid arterial compliance was increased 60min after HII exercise (p = .049) and was greater than 60min after MOD exercise (p = .02). AIx75 increased 10 min after both HII and MOD exercise (p < .05). There were significant correlations between some of the exercise‐induced changes in individual ci‐miRs and changes in cf‐PWV and AIx/AIx75. These results support the hypotheses that arterial stiffness and ci‐miRs are altered in an exercise intensity‐dependent manner, and ci‐miRs may contribute to changes in arterial stiffness.

Race-specific changes in endothelial inflammation and microRNA in response to an acute inflammatory stimulus

Both aberrant vascular reactivity to acute cardiovascular stress and epigenetic mechanisms such as microRNA (miR) may underlie the increased propensity for African Americans (AA) to develop cardiovascular disease. This study assessed racial differences in acute induced endothelial inflammation and related miRs. Cultured human umbilical vein endothelial cells (HUVECs) derived from AA and Caucasian Americans (CA) were exposed to influenza vaccine to determine changes in inflammatory markers, endothelial nitric oxide synthase (eNOS), and miR expression/release. Endothelial function [flow-mediated dilation (FMD)], circulating IL-6, and circulating miR were also measured in young, healthy AA and CA individuals before and after receiving the influenza vaccine. There were no significant racial differences in any parameters at baseline. The vaccine induced increases in IL-6 release (24%, P = 0.02) and ICAM-1 mRNA (40%, P = 0.03), as well as reduced eNOS mRNA (24%, P = 0.04) in AA HUVECs, but not in CA HUVECs (all P > 0.05). Intracellular levels of anti-inflammatory miR-221-3p and miR-222-3p increased specifically in CA HUVECs (72% and 53%, P = 0.04 and P = 0.06), whereas others did not change in either race. HUVEC secretion of several miRs decreased in both races, whereas the release of anti-inflammatory miR-150-5p was decreased only by AA cells (-30%, P = 0.03). In individuals of both races, circulating IL-6 increased approximately twofold 24 h after vaccination (both P < 0.01) and returned to baseline levels by 48 h, whereas FMD remained unchanged. Although macrovascular function was unaffected by acute inflammation in AA and CA individuals, AA endothelial cells exhibited increased susceptibility to acute inflammation and unique changes in related miR.NEW & NOTEWORTHY Used as an acute inflammatory stimulus, the influenza vaccine induced an inflammatory response and decreased eNOS gene expression in endothelial cells derived from African Americans, but not Caucasian Americans. Race-specific changes in intracellular expression and release of specific microRNAs also occurred and may contribute to an exaggerated inflammatory response in African Americans. In vivo, the vaccine caused similar systemic inflammation but had no effect on endothelial function or circulating microRNAs in individuals of either race.

Circulating microparticle concentrations across acute and chronic cardiovascular disease conditions

Concentrations of different circulating microparticles (MPs) may have clinical and physiological relevance to cardiovascular disease pathologies.

PURPOSE

To quantify plasma concentrations of CD31+/CD42b-, CD62E+, and CD34+ MPs across healthy individuals and those with coronary artery disease (CAD) or acute cardiovascular events (non-ST elevation myocardial infarction (NSTEMI)). Fasted blood was obtained from CAD patients (n = 10), NSTEMI patients (n = 13), and healthy older men (n = 15) 60-75 years old.

METHODS

CD31+/CD42b-, CD62E+, and CD34+ MPs were isolated from plasma and quantified using flow cytometry. Relationships between MP subtypes, fasting blood lipids, blood glucose, blood pressure, body mass index, and total number of medications were assessed.

RESULTS

Concentrations of CD31+/CD42b- MPs were significantly lower in CAD and NSTEMI subjects compared with healthy individuals (p = .02 and .003, respectively). No differences between groups were found for CD62E+ or CD34+ MPs (p > .05 for both). Surprisingly, among all variables assessed, only CD62E+ MP concentrations were positively correlated with triglyceride levels (p = .012) and inversely correlated with SBP (p = .03).

CONCLUSIONS

Our findings provide support for the use of different MP subtypes, specifically CD31+/CD42b- MPs, as a potential biomarker of cardiovascular disease. Importantly, results from this study should be looked at in adjunct to previous MP work in CVD conditions as a way of highlighting the complex interactions of variables such as comorbid conditions and medications on MP concentrations.

Sex-specific alterations in blood-borne factors in physically inactive individuals are detrimental to endothelial cell functions

Mechanisms underlying the protective effects of both habitual endurance exercise and the female sex on vascular function are incompletely understood. Blood-borne circulating factors, such as circulating microRNAs (ci-miRs), may partially explain these effects. Blood samples were obtained from young, healthy men and women who either habitually performed endurance exercise (endurance trained) or were relatively inactive (sedentary). Women were tested during the early follicular phase of the menstrual cycle or the placebo pill phase of oral contraceptive to control for estrogen. Cultured human umbilical vein endothelial cells (HUVECs) were exposed to participants' serum in migration, proliferation, and reactive oxygen species (ROS) assays. Real-time quantitative polymerase chain reaction was used to quantify an initial array of 84 cardiovascular disease (CVD)-related ci-miRs, followed by validation of 10 ci-miRs. All participants were devoid of traditional CVD risk factors, and circulating estradiol concentration was not different between groups. Serum of endurance-trained women induced greater HUVEC migration compared with serum of sedentary women. HUVEC ROS production was greater in response to serum of sedentary men compared with serum of endurance-trained men and sedentary women. There were sex effects on the levels of nine ci-miRs, with greater levels in men, while ci-miRs-140-5p and 145-5p were also higher in sedentary compared with endurance-trained men and/or women. In a sex-specific manner, habitual endurance exercise was associated with beneficial effects of serum on HUVECs. Thus, alterations in circulating factors may contribute to the protective effects of habitual endurance exercise on vascular health. Additionally, sex had a greater impact than habitual activity level on the levels of vascular-related ci-miRs.NEW & NOTEWORTHY Serum from sedentary women caused impaired endothelial migration, whereas serum from sedentary men elicited increased endothelial reactive oxygen species production as compared with serum from their endurance-trained counterparts. Select CVD-related circulating microRNAs (ci-miRs) were higher in men than women, while ci-miRs-140-5p and 145-5p were also higher in sedentary versus trained men and/or women. Our data suggest that alterations in circulating factors may contribute to the protective effects of habitual exercise and sex on vascular health.

The unfortunately long life of some retracted biomedical research publications

In 2005 the scientific misconduct case of a noted researcher concluded with, among other things, the retraction of 10 papers. However, these articles continue to be cited at relatively high rates. The objectives of this paper are: 1) to track the retraction process of these papers, 2) to assess the impact of retraction on subsequent citation rates of these papers, and 3) to compare the citation history of these retracted articles and five other high-profile retraction cases. For objective 1, all five articles to be retracted were retracted and of the four to be corrected, two were retracted and two were corrected. Eight PubMed and journal sites were identified where retraction messages could be conveyed; the number of retraction messages averaged 3.4 ± 2.5 for these nine articles. For objective 2, an absolute "cleansing" did not occur. While it initially appears there was a relative "cleansing," as citation rates for these articles did decrease after retraction, the reductions in citation rates for these articles (-28%) were the same as those for matched nonretracted publications both by the same author (-28%) and by another investigator (-29%) over the same time frame. Relative to objective 3, the results for this case are quite different from the five other cases assessing this issue, perhaps because of this investigator's "citation inertia" as a result of the small percentage of his papers that were retracted and the large number of citations to the articles before their retraction and to all of his published articles.NEW & NOTEWORTHY The scientific misconduct and fraud case of a noted exercise physiology researcher was concluded ~15 yr ago, and one the of the results was the retraction of 10 published manuscripts. However, based on a number of comparisons to that same author's and another investigator's citation histories for similar articles, the citation histories for these retracted articles appear to not have been affected whatsoever in the subsequent 15 yr.

The effects of moderate and high-intensity exercise on circulating markers of endothelial integrity and activation in young, healthy men

Endothelial function typically exhibits a hormetic response to exercise. It is unknown whether endothelial damage occurs in response to acute exercise and could be a contributing mechanism. We sought to determine the effects of acute exercise on endothelial-derived circulating factors proposed to reflect endothelial integrity and activation. Young, healthy men (n = 10) underwent 30-min moderate continuous (MOD) and high-intensity interval (HII) cycling exercise bouts. Venous blood samples were taken immediately before and after exercise for quantification of circulating endothelial cells (CECs), circulating angiogenic cells (CACs), apoptotic and activated endothelial microvesicles (EMVs), thrombomodulin (TM), von Willebrand factor (vWF), syndecan-1, and circulating microRNAs (ci-miRs) 126-3p and 126-5p. Endothelial function was assessed by flow-mediated dilation (FMD) of the brachial artery before, 10 min after, and 60 min after exercise. Numbers of CECs and EMVs were unchanged by either exercise bout (P > 0.05). Numbers of all measured CAC subtypes decreased in response to MOD (21%-34%, P < 0.05), whereas only CD31⁺/34⁺/45^dim/- CACs decreased following HII (21%, P < 0.05). TM and syndecan-1 increased with both exercise intensities (both ~20%, P < 0.05). HII, but not MOD, increased vWF (88%, P < 0.001), ci-miR-126-3p (92%, P = 0.009) and ci-miR-126-5p (110%, P = 0.01). The changes in several circulating factors correlated with changes in FMD following either one or both intensities. Changes in circulating factors do not support the concept of exercise-induced endothelial cell denudation, apoptosis, or activation, though slight disruption of endothelial glycocalyx and membrane integrity may occur. A related loss of mechanotransduction along with mechanisms underlying endothelial activation and ci-miR-126 secretion may relate to changes in endothelial function.NEW & NOTEWORTHY Using circulating endothelial-derived factors, we show that endothelial denudation, apoptosis, and activation do not appear to increase, whereas disrupted endothelial glycocalyx and membrane integrity may occur during both high-intensity interval and moderate intensity cycling. Increases in factors nonspecific to endothelial damage, including von Willebrand factor and microRNA-126, occurred only after high-intensity interval exercise. These results shed light on the hypothesis that disrupted endothelial integrity contributes to the endothelial function response to exercise.

Circulating microRNAs and endothelial cell migration rate are associated with metabolic syndrome and fitness level in postmenopausal African American women

Postmenopausal African American women are at elevated risk for metabolic syndrome (MetS), which predisposes them to cardiovascular disease and other chronic diseases. Circulating microRNAs (ci-miR) are potential mediators of cardiometabolic diseases also impacted by cardiorespiratory fitness (CRF) level. Using real-time quantitative PCR, we compared the expression of vascular-related ci-miRs (miR-21-5p, miR-92a-3p, miR-126-5p, miR-146a-5p, miR-150-5p, miR-221-3p) in sedentary, overweight/obese, postmenopausal African American women based on 1) presence (n = 31) or absence (n = 42) of MetS and 2) CRF level (VO2peak ) (Very Low < 18.0 mL·kg-1 ·min-1 [n = 31], Low = 18.0-22.0 mL·kg-1 ·min-1 [n = 24], or Moderate >22.0 mL·kg-1 ·min-1 [n = 18]). Endothelial migration rate in response to subjects' serum was assessed to determine the effect of circulating blood-borne factors on endothelial repair. Ci-miR-21-5p was the only ci-miR that differed between women with MetS compared to those without MetS (0.93 ± 0.43 vs. 1.28 ± 0.71, P = 0.03). There were borderline significant differences (P = 0.06-0.09) in ci-miR-21-5p, 126-5p, and 221-3p levels between the CRF groups, and these three ci-miRs correlated with VO2peak (r = -0.25 to -0.28, P < 0.05). Endothelial migration rate was impaired in response to serum from women with MetS compared to those without after 16-24 h. Serum from women with Moderate CRF induced greater endothelial migration than the Very Low and Low CRF groups after 4 and 16-24 h, that was also not different from a young, healthy reference group. Ci-miR-21-5p is lower in postmenopausal African American women with MetS, while ci-miRs-21-5p, 126-5p, and 221-3p are associated with CRF. Factors which impair endothelial cell migration rate are present in serum of women with MetS, though having Moderate CRF may be protective.

Exercise and Cardiovascular Progenitor Cells

Autologous stem/progenitor cell-based methods to restore blood flow and function to ischemic tissues are clinically appealing for the substantial proportion of the population with cardiovascular diseases. Early preclinical and case studies established the therapeutic potential of autologous cell therapies for neovascularization in ischemic tissues. However, trials over the past ∼15 years reveal the benefits of such therapies to be much smaller than originally estimated and a definitive clinical benefit is yet to be established. Recently, there has been an emphasis on improving the number and function of cells [herein generally referred to as circulating angiogenic cells (CACs)] used for autologous cell therapies. CACs include of several subsets of circulating cells, including endothelial progenitor cells, with proangiogenic potential that is largely exerted through paracrine functions. As exercise is known to improve CV outcomes such as angiogenesis and endothelial function, much attention is being given to exercise to improve the number and function of CACs. Accordingly, there is a growing body of evidence that acute, short-term, and chronic exercise have beneficial effects on the number and function of different subsets of CACs. In particular, recent studies show that aerobic exercise training can increase the number of CACs in circulation and enhance the function of isolated CACs as assessed in ex vivo assays. This review summarizes the roles of different subsets of CACs and the effects of acute and chronic exercise on CAC number and function, with a focus on the number and paracrine function of circulating CD34+ cells, CD31+ cells, and CD62E+ cells. © 2019 American Physiological Society. Compr Physiol 9:767-797, 2019.

The historical context and scientific legacy of John O. Holloszy

John O. Holloszy, as perhaps the world's preeminent exercise biochemist/physiologist, published >400 papers over his 50+ year career, and they have been cited >41,000 times. In 1965 Holloszy showed for the first time that exercise training in rodents resulted in a doubling of skeletal muscle mitochondria, ushering in a very active era of skeletal muscle plasticity research. He subsequently went on to describe the consequences of and the mechanisms underlying these adaptations. Holloszy was first to show that muscle contractions increase muscle glucose transport independent of insulin, and he studied the mechanisms underlying this response throughout his career. He published important papers assessing the impact of training on glucose and insulin metabolism in healthy and diseased humans. Holloszy was at the forefront of rodent studies of caloric restriction and longevity in the 1980s, following these studies with important cross-sectional and longitudinal caloric restriction studies in humans. Holloszy was influential in the discipline of cardiovascular physiology, showing that older healthy and diseased populations could still elicit beneficial cardiovascular adaptations with exercise training. Holloszy and his group made important contributions to exercise physiology on the effects of training on numerous metabolic, hormonal, and cardiovascular adaptations. Holloszy's outstanding productivity was made possible by his mentoring of ~100 postdoctoral fellows and substantial NIH grant funding over his entire career. Many of these fellows have also played critical roles in the exercise physiology/biochemistry discipline. Thus it is clear that exercise biochemistry and physiology will be influenced by John Holloszy for numerous years to come.

Effects of regular endurance exercise on GlycA: Combined analysis of 14 exercise interventions

BACKGROUND AND AIMS

GlycA is a relatively new biomarker for inflammation as well as cardiometabolic disease risk. However, the effect of exercise on GlycA is largely unknown. Therefore, the purpose of this study was to examine the effects of regular exercise on the inflammatory marker GlycA across seven studies and 14 exercise interventions.

METHODS

Nuclear magnetic resonance spectroscopy, specifically signal amplitudes originating from the N-acetyl methyl group protons of the N-acetylglucosamine residues on the glycan branches of glycoproteins, was used to quantify GlycA concentrations. GlycA was measured before and after completion of an exercise intervention in 1568 individuals across seven studies and 14 exercise interventions. Random effects inverse variance weighting models were used to pool effects across interventions.

RESULTS

Combined analysis of unadjusted data showed that regular exercise significantly (p = 2 × 10-6) reduced plasma GlycA (-8.26 ± 1.8 μmol/L). This reduction remained significant (-9.12 ± 1.9 μmol/L, p = 1.22 × 10-6) following adjustment for age, sex, race, baseline BMI, and baseline GlycA. Changes in GlycA were correlated with changes in traditional inflammatory markers, C-reactive protein, interleukin-6, and fibrinogen, however, these correlations were relatively weak (range r: 0.21-0.38, p < 0.0001).

CONCLUSIONS

Regular exercise significantly reduced plasma GlycA across 14 different exercise interventions despite differences in exercise programs and study populations. The current study provides a greater understanding of the use of exercise as a potential therapy for the reduction of systemic inflammation. Further research is needed to understand the mechanisms behind the exercise-related reductions in GlycA.

Trends in aggressive play and refereeing among the top five European soccer leagues

Current trends suggest professional soccer is becoming less aggressive, with England often argued to have the most aggressive of the top European leagues. The purpose of this study was to investigate differences in fouls and cards as indicators of aggressive play in the first divisions of England, France, Germany, Italy, and Spain over the past decade. Number of fouls per match and per yellow card has decreased in all leagues since 2007/08, though attempted tackles per foul has not changed or has increased. A lack of substantial rule changes suggests players have become less aggressive in tackling as opposed to referees becoming more lenient. Total number of fouls and cards per match were consistently lower in the English Premier League, however attempted tackles per foul was higher. The data also demonstrate the notions of home advantage and potentially referee bias, since referees tended to call more fouls and award more cards to away teams. Lastly, number of attempted tackles per foul and yellow cards received exhibited the strongest correlations with final league position across the leagues. In conclusion, our data support that elite European soccer has become less aggressive and the English Premier League is the most aggressive league.

Laboratory and Match Physiological Data From an Elite Male Collegiate Soccer Athlete

This study compared physiological data from an elite collegiate soccer player to those of his teammates over 2 seasons. The player of special interest (player A) was the winner of the MAC Hermann Trophy and was therefore considered the top player in National Collegiate Athletic Association (NCAA) division I soccer for each of the 2 seasons in which data were collected. Maximal oxygen consumption (V[Combining Dot Above]O2max) was measured during preseasons and heart rate (HR) was recorded during competitive matches. Polar Training Loads (PTL) were calculated using the Polar Team2 Pro (Polar USA) system based on time spent in HR zones. Player A had a lower V[Combining Dot Above]O2max than the team average in 2012 (56 vs. 61.5 ± 4.3 ml·kg·min) and a similar value in 2013 (54 vs. 56.9 ± 5.1 ml·kg·min). During matches, player A showed consistent significant differences from the team in percentage of time spent at 70-79% maximal heart rate (HRmax) (12.8 ± 5.5% vs. 10.1 ± 4.0%), 80-89% HRmax (54.3 ± 11.5% vs. 29.3 ± 6.8%), and 90-100% HRmax (23.1 ± 10.6% vs. 45.4 ± 8.5%). This led to a consistently lower PTL per minute accumulated by player A compared with his teammates (3.6 ± 0.4 vs. 4.4 ± 0.3), which may be beneficial over a season and may be related to his success. Thus, the ability to regulate moments of maximal exertion is useful in reducing training load and may be a characteristic of elite players, although whether our findings relate to differences in the playing style, position, or aerobic capacity of player A are unknown.

Circulating microRNAs in acute and chronic exercise: more than mere biomarkers

MicroRNAs (miRNAs) are short, noncoding RNAs that influence biological processes by regulating gene expression after transcription. It was recently discovered that miRNAs are released into the circulation (ci-miRNAs) where they are highly stable and can act as intercellular messengers to affect physiological processes. This review provides a comprehensive summary of the studies to date that have investigated the effects of acute exercise and exercise training on ci-miRNAs in humans. Findings indicate that specific ci-miRNAs are altered in response to different protocols of acute and chronic exercise in both healthy and diseased populations. In some cases, altered ci-miRNAs correlate with fitness and health parameters, suggesting causal mechanisms by which ci-miRNAs may facilitate adaptations to exercise training. However, strong data supporting such mechanisms are lacking. Thus, a purpose of this review is to guide future studies by discussing current and novel proposed roles for ci-miRNAs in adaptations to exercise training. In addition, substantial, fundamental gaps in the field need to be addressed. The ultimate goal of this research is that an understanding of the roles of ci-miRNAs in physiological adaptations to exercise training will one day translate to therapeutic interventions.

Investigating the extremes of the continuum of paracrine functions in CD34-/CD31+ CACs across diverse populations

Paracrine function of circulating angiogenic cells (CACs) is thought to contribute to vascular maintenance. We previously identified S100A8 and S100A9 secreted from physically inactive individuals' CD34^-/CD31⁺ CACs as negative regulators of capillary-like network formation. The purpose of this study was to investigate further the extremes of the continuum of CAC paracrine actions using two distinctly different groups representing "healthy" and "impaired" CAC function. We aimed to determine how capillary-like network formation in human umbilical vein endothelial cells (HUVECs) is affected by S100A8 and S100A9 in concentrations secreted by CACs from different ends of the health spectrum. CD34^-/CD31⁺ CACs were isolated and cultured from 10 impaired function individuals defined as older (50-89 yr), non-ST-elevation myocardial infarction patients and 10 healthy individuals defined as younger (18-35 yr), healthy individuals, and conditioned media (CM) was generated. CM from the impaired function group's CACs significantly diminished network formation compared with CM from the healthy group (P < 0.05). We identified elevations in S100A8, S100A9, and S100A8/A9 in the CM from the impaired function group (P < 0.05). Pretreatment of HUVECs with inhibitors to a known S100A8 and S100A9 receptor, Toll-like receptor 4 (TLR4), but not receptor for advanced glycation end products, improved HUVEC network formation (P < 0.05) compared with CM alone in the impaired function conditions. Exposure of HUVECs to the TLR4 signaling inhibitor also blocked recombinant S100A8- and S100A9-mediated reductions in network formation. Collectively, the results suggest that the mechanisms behind impaired CAC CD34^-/CD31⁺ CM-mediated reductions in capillary-like network formation involve secretion of S100A8 and S100A9 and binding of these proteins to TLR4 receptors on HUVECs.

NEW & NOTEWORTHY

S100A8 and S100A9 proteins in concentrations secreted by CD34^-/CD31⁺ circulating angiogenic cells (CACs) with impaired function reduce endothelial cell capillary-like network formation. These effects appear to be mediated by Toll-like receptor 4 and are absent with S100A8 and S100A9 in concentrations secreted by healthy CD34^-/CD31⁺ CACs.

Hippocampal and Cerebral Blood Flow after Exercise Cessation in Master Athletes

While endurance exercise training improves cerebrovascular health and has neurotrophic effects within the hippocampus, the effects of stopping this exercise on the brain remain unclear. Our aim was to measure the effects of 10 days of detraining on resting cerebral blood flow (rCBF) in gray matter and the hippocampus in healthy and physically fit older adults. We hypothesized that rCBF would decrease in the hippocampus after a 10-day cessation of exercise training. Twelve master athletes, defined as older adults (age ≥ 50 years) with long-term endurance training histories (≥15 years), were recruited from local running clubs. After screening, eligible participants were asked to cease all training and vigorous physical activity for 10 consecutive days. Before and immediately after the exercise cessation period, rCBF was measured with perfusion-weighted MRI. A voxel-wise analysis was used in gray matter, and the hippocampus was selected a priori as a structurally defined region of interest (ROI), to detect rCBF changes over time. Resting CBF significantly decreased in eight gray matter brain regions. These regions included: (L) inferior temporal gyrus, fusiform gyrus, inferior parietal lobule, (R) cerebellar tonsil, lingual gyrus, precuneus, and bilateral cerebellum (FWE p < 0.05). Additionally, rCBF within the left and right hippocampus significantly decreased after 10 days of no exercise training. These findings suggest that the cerebrovascular system, including the regulation of resting hippocampal blood flow, is responsive to short-term decreases in exercise training among master athletes. Cessation of exercise training among physically fit individuals may provide a novel method to assess the effects of acute exercise and exercise training on brain function in older adults.

Short-term exercise training improves flow-mediated dilation and circulating angiogenic cell number in older sedentary adults

Cardiovascular disease risk increases with age due, in part, to impaired endothelial function and decreased circulating angiogenic cell (CAC) number and function. We sought to determine if 10 days of aerobic exercise training improves endothelial function, CAC number, and intracellular redox balance in older sedentary adults. Eleven healthy subjects (4 men, 7 women), 61 ± 2 years of age participated in 60 min of aerobic exercise at 70% maximal oxygen consumption for 10 consecutive days while maintaining body weight. Before and after training, endothelial function was measured as flow-mediated dilation of the brachial artery and fasting blood was drawn to enumerate 3 CAC subtypes. Intracellular reactive oxygen species (ROS) and nitric oxide (NO) in CD34+ CACs were measured using fluorescent probes and reinforced via real-time quantitative polymerase chain reaction. Flow-mediated dilation improved significantly following training (10% ± 1.3% before vs. 16% ± 1.4% after training; P < 0.05). Likewise, CD34+/KDR+ number increased 104% and KDR+ number increased 151% (P < 0.05 for both), although CD34+ number was not significantly altered (P > 0.05). Intracellular NO and ROS levels in CD34+ CACs were not different after training (P > 0.05 for both). Messenger RNA expression of SOD1, endothelial nitric oxide synthase, and NADPH oxidase 2 and neutrophil cytosolic factor 1 in CD34+ CACs was not significantly altered with training (P > 0.05). In conclusion, 10 consecutive days of aerobic exercise increased flow-mediated dilation and CAC number in older, previously sedentary adults, but did not affect intracellular redox balance in CD34+ CACs. Overall, these data indicate that even short-term aerobic exercise training can have a significant impact on cardiovascular disease risk factors.

Advances in exercise, fitness, and performance genomics in 2014

This is the annual review of the exercise genomics literature in which we report on the highest quality papers published in 2014. We identified a number of noteworthy papers across a number of fields. In 70-89 yr olds, only 19% of angiotensin-converting enzyme (ACE) II homozygotes exhibited significant improvement in gait speed in response to a yearlong physical activity program compared to 30% of ACE D-allele carriers. New studies continue to support the notion that the genetic susceptibility to obesity, as evidenced by a genomic risk score (GRS; based on multiple single nucleotide polymorphisms), is attenuated by 40%-50% in individuals who are physically active, compared to those who are sedentary. One study reported that the polygenic risk for hypertriglyceridemia was reduced by 30%-40% in individuals with high cardiorespiratory fitness. One report showed that there was a significant interaction of a type 2 diabetes GRS with physical activity, with active individuals having the lowest risk of developing diabetes. The protective effect of physical activity was most pronounced in the low GRS tertile (hazard ratio, 0.82). The interaction observed with the diabetes GRS seemed to be dependent on a genetic susceptibility to insulin resistance and not insulin secretion. A significant interaction between PPARα sequence variants and physical activity levels on cardiometabolic risk was observed, with higher activity levels associated with lower risk only in carriers of specific genotypes and haplotypes. The review concludes with a discussion of the importance of replication studies when very large population or intervention discovery studies are not feasible or are cost prohibitive.

The effects of exercise on the lipoprotein subclass profile: A meta-analysis of 10 interventions

OBJECTIVE

The goal was to examine lipoprotein subclass responses to regular exercise as measured in 10 exercise interventions derived from six cohorts.

METHODS

Nuclear magnetic resonance spectroscopy was used to quantify average particle size, total and subclass concentrations of very low-density lipoprotein, low-density lipoprotein, and high-density lipoprotein particles (VLDL-P, LDL-P, and HDL-P, respectively) before and after an exercise intervention in 1555 adults from six studies, encompassing 10 distinct exercise programs: APOE (N = 106), DREW (N = 385), GERS (N = 79), HERITAGE (N = 715), STRRIDE I (N = 168) and II (N = 102). Random-effects meta-analyses were performed to evaluate the overall estimate of mean change across the unadjusted and adjusted mean change values from each exercise group.

RESULTS

Meta-analysis of unadjusted data showed that regular exercise induced significant decreases in the concentration of large VLDL-P, small LDL-P, and medium HDL-P and mean VLDL-P size, with significant increases in the concentration of large LDL-P and large HDL-P and mean LDL-P size. These changes remained significant in meta-analysis with adjustment for age, sex, race, baseline body mass index, and baseline trait value.

CONCLUSIONS

Despite differences in exercise programs and study populations, regular exercise produced putatively beneficial changes in the lipoprotein subclass profile across 10 exercise interventions. Further research is needed to examine how exercise-induced changes in lipoprotein subclasses may be associated with (concomitant changes in) cardiovascular disease risk.

Chronic endurance exercise affects paracrine action of CD31+ and CD34+ cells on endothelial tube formation

We aimed to determine if chronic endurance-exercise habits affected redox status and paracrine function of CD34(+) and CD34(-)/CD31(+) circulating angiogenic cells (CACs). Subjects were healthy, nonsmoking men and women aged 18-35 yr and categorized by chronic physical activity habits. Blood was drawn from each subject for isolation and culture of CD34(+) and CD34(-)/CD31(+) CACs. No differences in redox status were found in any group across either cell type. Conditioned media (CM) was generated from the cultured CACs and used in an in vitro human umbilical vein endothelial cell-based tube assay. CM from CD34(+) cells from inactive individuals resulted in tube structures that were 29% shorter in length (P < 0.05) and 45% less complex (P < 0.05) than the endurance-trained group. CD34(-)/CD31(+) CM from inactive subjects resulted in tube structures that were 26% shorter in length (P < 0.05) and 42% less complex (P < 0.05) than endurance-trained individuals. Proteomics analyses identified S100A8 and S100A9 in the CM. S100A9 levels were 103% higher (P < 0.05) and S100A8 was 97% higher in the CD34(-)/CD31(+) CM of inactive subjects compared with their endurance-trained counterparts with no significant differences in either protein in the CM of CD34(+) CACs as a function of training status. Recombinant S100A8/A9 treatment at concentrations detected in inactive subjects' CD34(-)/CD31(+) CAC CM also reduced tube formation (P < 0.05). These findings are the first, to our knowledge, to demonstrate a differential paracrine role in CD34(+) and CD34(-)/CD31(+) CACs on tube formation as a function of chronic physical activity habits and identifies a differential secretion of S100A9 by CD34(-)/CD31(+) CACs due to habitual exercise.

Advances in exercise, fitness, and performance genomics in 2013

The most significant and scientifically sound articles in exercise genomics that were published in 2013 are reviewed in this report. No article on the genetic basis of sedentary behavior or physical activity level was identified. A calcineurin- and alpha actinin-2-based mechanism has been identified as the potential molecular basis for the observed lower muscular strength and power in alpha actinin-3-deficient individuals. Although baseline muscle transcriptomic signatures were found to be associated with strength training-induced muscle hypertrophy, no predictive genomic variants could be identified as of yet. One study found no clear evidence that the inverse relation between physical activity level and incident CHD events was influenced by 58 genomic variants clustered into four genetic scores. Lower physical activity level in North American populations may be driving the apparent risk of obesity in fat mass- and obesity-associated gene (FTO)-susceptible individuals compared with more active populations. Two large studies revealed that common genetic variants associated with baseline levels of plasma HDL cholesterol and triglycerides are not clear predictors of changes induced by interventions focused on weight loss, diet, and physical activity behavior. One large study from Japan reported that a higher fitness level attenuated the arterial stiffness-promoting effect of the Ala54 allele at the fatty acid binding protein 2 locus, which is a controversial finding because previous studies have suggested that Thr54 was the risk allele. Using transcriptomics to generate genomic targets in an unbiased manner for subsequent DNA sequence variants studies appears to be a growing trend. Moreover, exercise genomics is rapidly embracing gene and pathway analysis to better define the underlying biology and provide a foundation for the study of human variation.

Circulating angiogenic and inflammatory cytokine responses to acute aerobic exercise in trained and sedentary young men

PURPOSE

Endurance exercise training can ameliorate many cardiovascular and metabolic disorders and attenuate responses to inflammatory stimuli. The purpose of this study was to determine whether the angiogenic and pro-inflammatory cytokine response to acute endurance exercise differs between endurance-trained and sedentary young men.

METHODS

Ten endurance-trained and ten sedentary healthy young men performed 30 min of treadmill running at 75 % VO2max with blood sampling before and after exercise. Plasma concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-8, IL-6, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), placental growth factor (PlGF), and soluble VEGF receptor-1 (sFlt-1) were measured by multiplex ELISA.

RESULTS

Acute exercise increased IL-6 by 165 % (P < 0.05), IL-8 by 32 % (P < 0.05), PlGF by ~16 % (P < 0.05), sFlt-1 by 36 % (P < 0.001), and tended to increase bFGF by ~25 % (P = 0.06) in main effects analyses. TNF-α and VEGF did not change significantly with exercise in either group. Contrary to our hypothesis, there were no significant differences in TNF-α, IL-6, VEGF, bFGF, PlGF, or sFlt-1 between groups before or after acute exercise; however, there was a tendency for IL-8 concentrations to be higher in endurance-trained subjects compared to sedentary subjects (P = 0.06).

CONCLUSIONS

These results indicate that 30 min of treadmill running at 75 % VO2max produces a systemic angiogenic and inflammatory reaction, but endurance exercise training does not appear to significantly alter these responses in healthy young men.

Advances in exercise, fitness, and performance genomics in 2012

A small number of excellent articles on exercise genomics issues were published in 2012. A new PYGM knock-in mouse model will provide opportunities to investigate the exercise intolerance and very low activity level of people with McArdle disease. New reports on variants in ACTN3 and ACE have increased the level of uncertainty regarding their true role in skeletal muscle metabolism and strength traits. The evidence continues to accumulate on the positive effects of regular physical activity on body mass index or adiposity in individuals at risk of obesity as assessed by their FTO genotype or by the number of risk alleles they carry at multiple obesity-susceptibility loci. The serum levels of triglycerides and the risk of hypertriglyceridemia were shown to be influenced by the interactions between a single nucleotide polymorphism (SNP) in the NOS3 gene and physical activity level. Allelic variation at nine SNPs was shown to account for the heritable component of the changes in submaximal exercise heart rate induced by the HERITAGE Family Study exercise program. SNPs at the RBPMS, YWHAQ, and CREB1 loci were found to be particularly strong predictors of the changes in submaximal exercise heart rate. The 2012 review ends with comments on the importance of relying more on experimental data, the urgency of identifying panels of genomic predictors of the response to regular exercise and particularly of adverse responses, and the exciting opportunities offered by recent advances in our understanding of the global architecture of the human genome as reported by the Encyclopedia of DNA Elements project.

Effects of prior acute exercise on circulating cytokine concentration responses to a high-fat meal

High-fat meal consumption alters the circulating cytokine profile and contributes to cardiometabolic diseases. A prior bout of exercise can ameliorate the triglyceride response to a high-fat meal, but the interactive effects of exercise and high-fat meals on cytokines that mediate cardiometabolic risk are not fully understood. We investigated the effects of prior exercise on the responses of circulating tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-8, leptin, retinol-binding protein 4 (RBP4), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), placental growth factor (PlGF), and soluble fms-like tyrosine kinase-1 (sFlt-1) to a high-fat meal. Ten healthy men were studied before and 4 h after ingestion of a high-fat meal either with or without ∼50 min of endurance exercise at 70% of VO2 max on the preceding day. In response to the high-fat meal, lower leptin and higher VEGF, bFGF, IL-6, and IL-8 concentrations were evident (P < 0.05 for all). There was no effect of the high-fat meal on PlGF, TNF-α, or RBP4 concentrations. We found lower leptin concentrations with prior exercise (P < 0.05) and interactive effects of prior exercise and the high-fat meal on sFlt-1 (P < 0.05). The high-fat meal increased IL-6 by 59% without prior exercise and 218% with prior exercise (P < 0.05). In conclusion, a prior bout of endurance exercise does not affect all high-fat meal-induced changes in circulating cytokines, but does affect fasting or postprandial concentrations of IL-6, leptin, and sFlt-1. These data may reflect a salutary effect of prior exercise on metabolic responses to a high-fat meal.

Association Between Body Fat Response to Exercise Training and MultilocusADRGenotypes

OBJECTIVE

To examine the contribution of adrenergic receptor (ADR) gene polymorphisms and their gene-gene interactions to the variability of exercise training-induced body fat response.

RESEARCH METHODS AND PROCEDURES

This was an intervention study that used a volunteer sample of 70 healthy, sedentary men (n = 29) and postmenopausal women (n = 41) 50 to 75 years of age, with a BMI < or = 37 kg/m2, from the Washington, DC, metropolitan area. Participants completed 6 weeks of dietary stabilization (American Heart Association diet) before 24 weeks of supervised aerobic exercise training. Diet was maintained throughout the intervention. Change in percent total body fat, percent trunk fat, and fat mass by DXA in ADR genotype groups (Glu12/Glu9 alpha2b-ADR, Trp64Arg beta3-ADR, and Gln27Glu beta2-ADR) at baseline and after 24 weeks of aerobic exercise training was measured.

RESULTS

In multivariate analysis (covariates: age, gender, and baseline value of phenotype), best fit models for percent total body and trunk fat response to exercise training retained main effects of all three ADR gene loci and the effects of each gene-gene interaction (p = 0.009 and 0.003, respectively). Similarly, there was a trend for the fat mass response model (p = 0.03). The combined genetic factors explained 17.5% of the overall model variability for percent total body fat, 22% for percent trunk fat, and 10% for fat mass.

DISCUSSION

The body fat response to exercise training in older adults is associated with the combined effects of the Glu12/Glu9 alpha2b-, Trp64Arg beta3-, and Gln27Glu beta2-ADR gene variants and their gene-gene interactions.

Advances in exercise, fitness, and performance genomics in 2011

This review of the exercise genomics literature emphasizes the highest quality articles published in 2011. Given this emphasis on the best publications, only a small number of published articles are reviewed. One study found that physical activity levels were significantly lower in patients with mitochondrial DNA mutations compared with controls. A two-stage fine-mapping follow-up of a previous linkage peak found strong associations between sequence variation in the activin A receptor, type-1B (ACVRIB) gene and knee extensor strength, with rs2854464 emerging as the most promising candidate polymorphism. The association of higher muscular strength with the rs2854464 A allele was confirmed in two separate cohorts. A study using a combination of transcriptomic and genomic data identified a comprehensive map of the transcriptomic features important for aerobic exercise training-induced improvements in maximal oxygen consumption, but no genetic variants derived from candidate transcripts were associated with trainability. A large-scale de novo meta-analysis confirmed that the effect of sequence variation in the fat mass and obesity-associated (FTO) gene on the risk of obesity differs between sedentary and physically active adults. Evidence for gene-physical activity interactions on type 2 diabetes risk was found in two separate studies. A large study of women found that physical activity modified the effect of polymorphisms in the lipoprotein lipase (LPL), hepatic lipase (LIPC), and cholesteryl ester transfer protein (CETP) genes, identified in previous genome-wide association study reports, on HDL cholesterol. We conclude that a strong exercise genomics corpus of evidence would not only translate into powerful genomic predictors but also have a major effect on exercise biology and exercise behavior research.

Adverse metabolic response to regular exercise: is it a rare or common occurrence?

Background

Individuals differ in the response to regular exercise. Whether there are people who experience adverse changes in cardiovascular and diabetes risk factors has never been addressed.

Methodology/Principal Findings

An adverse response is defined as an exercise-induced change that worsens a risk factor beyond measurement error and expected day-to-day variation. Sixty subjects were measured three times over a period of three weeks, and variation in resting systolic blood pressure (SBP) and in fasting plasma HDL-cholesterol (HDL-C), triglycerides (TG), and insulin (FI) was quantified. The technical error (TE) defined as the within-subject standard deviation derived from these measurements was computed. An adverse response for a given risk factor was defined as a change that was at least two TEs away from no change but in an adverse direction. Thus an adverse response was recorded if an increase reached 10 mm Hg or more for SBP, 0.42 mmol/L or more for TG, or 24 pmol/L or more for FI or if a decrease reached 0.12 mmol/L or more for HDL-C. Completers from six exercise studies were used in the present analysis: Whites (N = 473) and Blacks (N = 250) from the HERITAGE Family Study; Whites and Blacks from DREW (N = 326), from INFLAME (N = 70), and from STRRIDE (N = 303); and Whites from a University of Maryland cohort (N = 160) and from a University of Jyvaskyla study (N = 105), for a total of 1,687 men and women. Using the above definitions, 126 subjects (8.4%) had an adverse change in FI. Numbers of adverse responders reached 12.2% for SBP, 10.4% for TG, and 13.3% for HDL-C. About 7% of participants experienced adverse responses in two or more risk factors.

Conclusions/Significance

Adverse responses to regular exercise in cardiovascular and diabetes risk factors occur. Identifying the predictors of such unwarranted responses and how to prevent them will provide the foundation for personalized exercise prescription.

Aerobic training effects on glucose tolerance in prediabetic and normoglycemic humans

INTRODUCTION

It is generally accepted that if prediabetic individuals adopt healthy lifestyle habits, the progression to type 2 diabetes mellitus can be prevented or delayed. However, the role of exercise training independent of other lifestyle factors has not been determined. Furthermore, patients with type 2 diabetes mellitus have been shown to experience greater training-induced changes in glucose and insulin metabolism compared with healthy subjects, but the adaptations of prediabetic individuals have not been adequately examined. We hypothesized that (i) prediabetic subjects would have greater endurance training-induced changes in plasma glucose and insulin responses to an oral glucose challenge compared with age- and body mass index-matched normoglycemic subjects and (ii) training would completely reverse the abnormal glucose metabolism of prediabetic subjects.

METHODS

Plasma glucose and insulin responses to oral glucose tolerance tests (OGTTs) were examined in normoglycemic (n = 119) and prediabetic (n = 47) older men and women before and after a 6-month standardized endurance exercise training program.

RESULTS

Prediabetic subjects had greater glucose and insulin OGTT responses than normoglycemic subjects both before and after training (P < 0.05). Prediabetic subjects had greater training-induced changes in glucose and insulin areas under the glucose tolerance curve, as well as greater changes in glucose and insulin concentrations at several points of the OGTT. However, these changes did not eliminate the baseline differences in glucose tolerance between normoglycemic and prediabetic subjects. The between-group differences in changes in glucose and insulin variables were largely independent of changes in body weight or composition.

CONCLUSIONS

Our data indicate that prediabetes is associated with greater training-induced changes in glucose tolerance. However, 6 months of endurance training alone was not sufficient to completely reverse prediabetes.

Aerobic exercise training increases circulating insulin-like growth factor binding protein-1 concentration, but does not attenuate the reduction in circulating insulin-like growth factor binding protein-1 after a high-fat meal

Insulin-like growth factor binding protein-1 (IGFBP-1) has metabolic effects throughout the body, and its expression is regulated in part by insulin. Circulating IGFBP-1 predicts development of cardiometabolic diseases in longitudinal studies, and low IGFBP-1 concentrations are associated with insulin resistance and consumption of a high-fat diet. Because of the favorable metabolic effects of regular aerobic exercise, we hypothesized that aerobic exercise training would increase plasma IGFBP-1 concentrations and attenuate the reduction in IGFBP-1 after a high-fat meal. Ten overweight (body mass index = 28.7 ± 0.9 kg/m(2)), older (61 ± 2 years) men and women underwent high-fat feeding and oral glucose tolerance tests at baseline and after 6 months of aerobic exercise training. In response to aerobic exercise training, subjects increased cardiorespiratory fitness by 13% (P < .05) and insulin sensitivity index by 28% (P < .05). Basal plasma concentrations of IGFBP-1 increased by 41% after aerobic exercise training (P < .05). The insulin response to an oral glucose tolerance test was a significant predictor of fasting plasma IGFBP-1 concentrations at baseline and after exercise training (P = .02). In response to the high-fat meal at baseline, plasma IGFBP-1 concentrations decreased by 58% (P < .001); a 61% decrease to similar postprandial concentrations was observed after exercise training (P < .001). Plasma insulin response to the high-fat meal was inversely associated with postprandial IGFBP-1 concentrations at baseline and after exercise training (P = .06 and P < .05, respectively). Although aerobic exercise training did not attenuate the response to a high-fat meal, the increase in IGFBP-1 concentrations after exercise training may be one mechanism by which exercise reduces risk for cardiometabolic diseases in older adults.

Nitro-oxidative stress biomarkers in active and inactive men

Oxidative stress markers are novel factors shown to be related to cardiovascular (CVD) risk. We examined the effects of long-term exercise, age, and their interaction on plasma oxidized LDL (ox-LDL), nitrotyrosine, and myeloperoxidase (MPO) levels, all biomarkers of oxidative stress, and determined their association with plasma nitric oxide (NOx) levels as an index of NO bioavailability. Older (62±2 yr) active men (n=12) who had exercised for >30 years and young (25±4 yr) active men (n=7) who had exercised for >3 years were age- and BMI-matched to older (n=11) and young (n=8) inactive men. Young subjects had lower plasma nitrotyrosine levels than older subjects (P=0.047). Young inactive subjects had higher ox-LDL levels than either the young active (P=0.042) or the older active (P=0.041) subjects. In addition, plasma oxidative stress levels, particularly ox-LDL, were correlated with various conventional plasma lipoprotein-lipid levels, and in older subjects were associated with Framingham risk score (r=0.49, P=0.015). We found no relationships between plasma oxidative stress markers and NOx levels. The findings suggest that a sedentary lifestyle may be associated with higher ox-LDL levels and that the levels of oxidative stress markers are related to levels of other conventional CVD risk factors and overall CVD risk.

Hepatic lipase gene -514C>T variant is associated with exercise training-induced changes in VLDL and HDL by lipoprotein lipase

Our objective was to test the hypothesis that a common polymorphism in the hepatic lipase (HL) gene (LIPC -514C>T, rs1800588) influences aerobic exercise training-induced changes in TG, very-low-density lipoprotein (VLDL), and high-density lipoprotein (HDL) through genotype-specific increases in lipoprotein lipase (LPL) activity and that sex may affect these responses. Seventy-six sedentary overweight to obese men and women aged 50-75 yr at risk for coronary heart disease (CHD) underwent a 24-wk prospective study of the LIPC -514 genotype-specific effects of exercise training on lipoproteins measured enzymatically and by nuclear magnetic resonance, postheparin LPL and HL activities, body composition by dual energy x-ray absorptiometry and computer tomography scan, and aerobic capacity. CT genotype subjects had higher baseline total cholesterol, HDL-C, HDL(2)-C, large HDL, HDL particle size, and large LDL than CC homozygotes. Exercise training elicited genotype-specific decreases in VLDL-TG (-22 vs. +7%; P < 0.05; CC vs. CT, respectively), total VLDL and medium VLDL, and increases in HDL-C (7 vs. 4%; P < 0.03) and HDL(3)-C with significant genotype×sex interactions for the changes in HDL-C and HDL(3)-C (P values = 0.01-0.02). There were also genotype-specific changes in LPL (+23 vs. -6%; P < 0.05) and HL (+7 vs. -24%; P < 0.01) activities, with LPL increasing only in CC subjects (P < 0.006) and HL decreasing only in CT subjects (P < 0.007). Reductions in TG, VLDL-TG, large VLDL, and medium VLDL and increases in HDL(3)-C and small HDL particles correlated significantly with changes in LPL, but not HL, activity only in CC subjects. This suggests that the LIPC -514C>T variant significantly affects training-induced anti-atherogenic changes in VLDL-TG, VLDL particles, and HDL through an association with increased LPL activity in CC subjects, which could guide therapeutic strategies to reduce CHD risk.

Prior endurance exercise prevents postprandial lipaemia-induced increases in reactive oxygen species in circulating CD31+ cells

We hypothesized that prior exercise would prevent postprandial lipaemia (PPL)-induced increases in intracellular reactive oxygen species (ROS) in three distinct circulating angiogenic cell (CAC) subpopulations. CD34(+), CD31(+)/CD14(-)/CD34(-), and CD31(+)/CD14(+)/CD34(-) CACs were isolated from blood samples obtained from 10 healthy men before and 4 h after ingesting a high fat meal with or without ∼50 min of prior endurance exercise. Significant PPL-induced increases in ROS production in both sets of CD31(+) cells were abolished by prior exercise. Experimental ex vivo inhibition of NADPH oxidase activity and mitochondrial ROS production indicated that mitochondria were the primary source of PPL-induced oxidative stress. The attenuated increases in ROS with prior exercise were associated with increased antioxidant gene expression in CD31(+)/CD14(-)/CD34(-) cells and reduced intracellular lipid uptake in CD31(+)/CD14(+)/CD34(-) cells. These findings were associated with systemic cardiovascular benefits of exercise, as serum triglyceride, oxidized low density lipoprotein-cholesterol, and plasma endothelial microparticle concentrations were lower in the prior exercise trial than the control trial. In conclusion, prior exercise completely prevents PPL-induced increases in ROS in CD31(+)/CD14(-)/CD34(-) and CD31(+)/CD14(+)/CD34(-) cells. The mechanisms underlying the effects of exercise on CAC function appear to vary among specific CAC types.