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Exercise Overrides Blunted Hypoxic Ventilatory Response in Prematurely Born Men.

ABSTRACT: Purpose:Pre-term birth provokes life-long anatomical and functional respiratory system sequelae. Although blunted hypoxic ventilatory response (HVR) is consistently observed in pre-term infants, it remains unclear if it persists with aging and, moreover, if it influences hypoxic exercise capacity. In addition, it remains unresolved whether the previously observed prematurity-related alterations in redox balance could contribute to HVR modulation. Methods:Twenty-one prematurely born adult males (gestational age = 29 ± 4 weeks], and 14 age matched controls born at full term (gestational age = 39 ± 2 weeks) underwent three tests in a randomized manner: (1) hypoxia chemo-sensitivity test to determine the resting and exercise poikilocapnic HVR and a graded exercise test to volitional exhaustion in (2) normoxia (FiO2 = 0.21), and (3) normobaric hypoxia (FiO2 = 0.13) to compare the hypoxia-related effects on maximal aerobic power (MAP). Selected prooxidant and antioxidant markers were analyzed from venous samples obtained before and after the HVR tests. Results:Resting HVR was lower in the pre-term (0.21 ± 0.21 L ? min-1 ? kg-1) compared to full-term born individuals (0.47 ± 0.23 L ? min-1 ? kg-1; p < 0.05). No differences were noted in the exercise HVR or in any of the measured oxidative stress markers before or after the HVR test. Hypoxia-related reduction of MAP was comparable between the groups. Conclusion:These findings indicate that blunted resting HVR in prematurely born men persists into adulthood. Also, active adults born prematurely seem to tolerate hypoxic exercise well and should, hence, not be discouraged to engage in physical activities in hypoxic environments. Nevertheless, the blunted resting HVR and greater desaturation observed in the pre-term born individuals warrant caution especially during prolonged hypoxic exposures.

SUBMITTER: Debevec T

PROVIDER: S-EPMC6476987 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Exercise Overrides Blunted Hypoxic Ventilatory Response in Prematurely Born Men.

Debevec Tadej T Pialoux Vincent V Millet Grégoire P GP Martin Agnès A Mramor Minca M Osredkar Damjan D

Frontiers in physiology 20190416

<h4>Purpose</h4>Pre-term birth provokes life-long anatomical and functional respiratory system sequelae. Although blunted hypoxic ventilatory response (HVR) is consistently observed in pre-term infants, it remains unclear if it persists with aging and, moreover, if it influences hypoxic exercise capacity. In addition, it remains unresolved whether the previously observed prematurity-related alterations in redox balance could contribute to HVR modulation.<h4>Methods</h4>Twenty-one prematurely bor ...[more]

PMID: 31040796

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Project description:ImportanceSurvivors of preterm birth often present with medical morbidities; however, variation in their long-term educational performance has not been well described.ObjectiveTo estimate the association between gestational age and 4 outcomes in school-aged children: readiness to enter kindergarten, scores on standardized tests in elementary and middle school, gifted status, and low performance.Design, setting, and participantsIn a retrospective cohort study, children born in Florida between 1992 and 2002 at 23 to 41 weeks' gestation who entered Florida's public schools between 1995 and 2012 were assessed for kindergarten readiness and tested in mathematics and reading in grades 3 through 8. Data analysis was performed from January 12, 2016, to March 1, 2017.ExposuresGestational age at birth.Main outcomes and measuresKindergarten readiness, scores on the Florida Comprehensive Achievement Test (FCAT), classified as gifted, and classified as low performance.ResultsA total of 1?527?113 singleton infants with gestational ages of 23 to 41 weeks born between 1992 and 2002 were matched to Florida public school records. Of these, 1?301?497 children were included in the analysis; 641?479 (49.3%) were girls. A total of 301 (65.0%) Florida children born at 23 to 24 weeks' gestation were designated as ready to start kindergarten. When the FCAT test scores were adjusted for potentially confounding maternal and infant variables, children born at 23 to 24 weeks' gestation performed 0.66 SD (95% CI, -0.73 to -0.59) lower compared with those born at full term. A total of 123?554 (9.5%) of all Florida-born public school students were considered gifted, including 17 (1.8%) of those born at 23 to 24 weeks' gestation. In comparison, 75?458 (5.8%) of all Florida-born public school students were low performing; 310 (33.5%) of these children had been born at 23 to 24 weeks' gestation. Kindergarten readiness, FCAT scores, and gifted status were positively related to gestational age, whereas low performance was inversely related to gestational age.Conclusions and relevanceAlthough gestational age has long been associated with poor educational performance, a sufficient proportion of children born near the limits of viability performed within expected school norms, warranting further investigation into how and why certain children are able to overcome the educational burdens that may follow preterm birth.

Project description:ContextPrematurely born children have a high risk of developmental and behavioral disabilities. Cerebral abnormalities at term age have been clearly linked with later behavior alterations, but existing studies did not focus on the amygdala. Moreover, studies of early amygdala development after premature birth in humans are scarce.ObjectiveTo compare amygdala volumes in very preterm infants at term equivalent age (TEA) and term born infants, and to relate premature infants' amygdala volumes with their performance on the Laboratory Temperament Assessment Battery (Lab-TAB) fear episode at 12 months.ParticipantsEighty one infants born between 2008 and 2014 at the University Hospitals of Geneva and Lausanne, taking part in longitudinal and functional imaging studies, who had undergone a magnetic resonance imaging (MRI) scan at TEA enabling manual amygdala delineation.OutcomesAmygdala volumes assessed by manual segmentation of MRI scans; volumes of cortical and subcortical gray matter, white matter and cerebrospinal fluid (CSF) automatically segmented in 66 infants; scores for the Lab-TAB fear episode for 42 premature infants at 12 months.ResultsAmygdala volumes were smaller in preterm infants at TEA than term infants (mean difference 138.03 mm(3), p < 0.001), and overall right amygdala volumes were larger than left amygdala volumes (mean difference 36.88 mm(3), p < 0.001). White matter volumes were significantly smaller (p < 0.001) and CSF volumes significantly larger (p < 0.001) in preterm than in term born infants, while cortical and subcortical gray matter volumes were not significantly different between groups. Amygdala volumes showed significant correlation with the intensity of the escape response to a fearsome toy (rs = 0.38, p = 0.013), and were larger in infants showing an escape response compared to the infants showing no escape response (mean difference 120.97 mm(3), p = 0.005). Amygdala volumes were not significantly correlated with the intensity of facial fear, distress vocalizations, bodily fear and positive motor activity in the fear episode.ConclusionOur results indicate that premature birth is associated with a reduction in amygdala volumes and white matter volumes at TEA, suggesting that altered amygdala development might be linked to alterations in white matter connectivity reported in premature infants. Moreover, our data suggests that such alterations might affect infants' fear-processing capabilities.

Project description:ImportancePreterm birth has been associated with cardiometabolic, respiratory, and neuropsychiatric disorders in adulthood. However, the prevalence of survival without any major comorbidities is unknown.ObjectiveTo determine the prevalence of survival without major comorbidities in adulthood among persons born preterm vs full-term.Design, setting, and participantsNational cohort study of all 2?566?699 persons born in Sweden from January 1, 1973, through December 31, 1997, who had gestational age data and who were followed up for survival and comorbidities through December 31, 2015 (ages 18-43 years).ExposuresGestational age at birth.Main outcomes and measuresSurvival without major comorbidities among persons born extremely preterm (22-27 weeks), very preterm (28-33 weeks), late preterm (34-36 weeks), or early term (37-38 weeks), compared with full-term (39-41 weeks). Comorbidities were defined using the Adolescent and Young Adult Health Outcomes and Patient Experience (AYA HOPE) Comorbidity Index, which includes conditions that commonly manifest in adolescence or young adulthood, including neuropsychiatric disorders; and the Charlson Comorbidity Index (CCI), which includes major chronic disorders predictive of mortality in adulthood. Poisson regression was used to determine prevalence ratios and differences, adjusted for potential confounders.ResultsIn this study population, 48.6% were female, 5.8% were born preterm, and the median age at end of follow-up was 29.8 years (interquartile range, 12.6 years). Of all persons born preterm, 54.6% were alive with no AYA HOPE comorbidities at the end of follow-up. Further stratified, this prevalence was 22.3% for those born extremely preterm, 48.5% for very preterm, 58.0% for late preterm, 61.2% for early term, and 63.0% for full-term. These prevalences were significantly lower for earlier gestational ages vs full-term (eg, adjusted prevalence ratios: extremely preterm, 0.35 [95% CI, 0.33 to 0.36; P?<?.001]; all preterm, 0.86 [95% CI, 0.85 to 0.86; P?<?.001]; adjusted prevalence differences: extremely preterm, -0.41 [95% CI, -0.42 to -0.40; P?<?.001]; all preterm, -0.09 [95% CI, -0.09 to -0.09; P?<?.001]). Using the CCI, the corresponding prevalences were 73.1% (all preterm), 32.5% (extremely preterm), 66.4% (very preterm), 77.1% (late preterm), 80.4% (early term), and 81.8% (full-term) (adjusted prevalence ratios: extremely preterm, 0.39 [95% CI, 0.38 to 0.41; P?<?.001]; all preterm, 0.89 [95% CI, 0.89 to 0.89; P?<?.001]; adjusted prevalence differences: extremely preterm, -0.50 [95% CI, -0.51 to -0.49; P?<?.001]; all preterm, -0.09 [95% CI, -0.09 to -0.09; P?<?.001]).Conclusions and relevanceAmong persons born preterm in Sweden between 1973 and 1997, the majority survived to early to mid-adulthood without major comorbidities. However, outcomes were worse for those born extremely preterm.

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Exercise Overrides Blunted Hypoxic Ventilatory Response in Prematurely Born Men.

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Exercise Overrides Blunted Hypoxic Ventilatory Response in Prematurely Born Men.

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