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BACKGROUND: Vitamin D (25OHD) can modulate pathways and mechanisms that regulate blood pressure (BP). Observational studies in children and adults have shown an inverse association between 25OHD and BP. Studies evaluating associations between 25OHD and BP in pediatric chronic kidney disease are limited. METHODS: We evaluated the associations between 25OHD and BP using data from the Chronic Kidney Disease in Children (CKiD) study. Clinic or ambulatory BP index was defined as participant's BP divided by 95th age-sex-height-specific BP percentile, an index > 1 suggests hypertension. Primary outcomes of interest were changes in systolic and diastolic clinic and ambulatory BP indices over follow-up. Linear mixed-effects models were used to evaluate associations between BP indices and 25OHD. RESULTS: The study cohort consisted of 370 participants who contributed 970 person-visits. A subset of 194 participants with ambulatory BP data contributed 465 person-visits. There was an association between baseline 25OHD levels and clinic systolic BP index such that for every 10 ng/ml lower 25OHD, clinic systolic BP index was 1.0% higher (95%CI: 0.2-1.8, p = 0.016) between participants. The association between clinic diastolic BP index with baseline 25OHD was not significant. For within-person changes, longitudinal decreases in 25OHD were not significantly associated with concomitant increases in clinic systolic or diastolic BP index. There were no significant associations between 25OHD levels at baseline or longitudinally with 24-h ABPM indices. CONCLUSIONS: Low 25OHD levels were associated with higher clinic systolic BP in children with CKD. Vitamin D supplementation to maintain normal 25OHD levels might be a useful adjunctive treatment in optimizing BP control in these high-risk patients.
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Extracorporeal membrane oxygenation (ECMO) support of critically ill pediatric patients is associated with increased risk of thromboembolic events, and unfractionated heparin is used commonly for anticoagulation. Given reports of acquired antithrombin (AT) deficiency in this patient population and associated concern for heparin resistance, AT activity measurement and off-label AT replacement have become common in pediatric ECMO centers despite limited optimal dosing regimens. We conducted a retrospective cohort study of pediatric ECMO patients (0 to <18 years) at a single academic center to characterize the pharmacokinetics (PK) of human plasma-derived AT. We demonstrated that a two-compartment turnover model appropriately described the PK of AT, and the parameter estimates for clearance, central volume, intercompartmental clearance, peripheral volume, and basal AT input under non-ECMO conditions were 0.338 dL/h/70 kg, 38.5 dL/70 kg, 1.16 dL/h/70 kg, 40.0 dL/70 kg, and 30.4 units/h/70 kg, respectively. Also, ECMO could reduce bioavailable AT by 50% resulting in 2-fold increase of clearance and volume of distribution. To prevent AT activity from falling below predetermined thresholds of 50% activity in neonates and 80% activity in older infants and children, we proposed potential replacement regimens for each age group, accompanied by therapeutic drug monitoring.
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Aim: We sought to determine if higher plasma levels of brain injury biomarkers neurofilament light (NfL), phosphorylated tau 181 (pT181), tau, and ubiquitin C-terminal hydrolase L1 (UCHL1) were associated with unfavorable outcomes in children supported on extracorporeal membrane oxygenation (ECMO) with and without preceding cardiac arrest. Methods: We conducted a secondary analysis of a two-center prospective observational study of ECMO patients 0-<18 years. Plasma concentrations of NfL, pT181, tau, and UCHL1 were measured on ECMO days 1, 2 and 3. Unfavorable outcome was defined as in-hospital mortality or discharge Pediatric Cerebral Performance Category (PCPC) >2 with decline from baseline PCPC among survivors. Results: Among 88 children on ECMO, mean tau levels were significantly higher on each of the first three ECMO days in children who underwent extracorporeal cardiopulmonary resuscitation (ECPR) compared to those with non-ECPR cardiac arrest or with no cardiac arrest preceding ECMO. Higher ECMO day 1 tau levels were significantly associated with increased hazard of unfavorable outcome in unadjusted (HR, 1.35, 95% CI 1.09-1.66) and adjusted (HR, 1.42; 95% CI 1.13-1.79) models. Higher levels of NfL or pT181 were not associated with increased hazard for unfavorable outcome in multivariable models. UCHL1 values were outside of detectable limits and thus deferred from analysis. Conclusions: Levels of tau were significantly associated with increased hazard of death or unfavorable neurologic outcome in unadjusted and adjusted models. Biomarkers of brain injury, particularly tau, may aid in detection of neurologic injury and neuroprognostication in patients on ECMO with and without preceding cardiac arrest.
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In this two-center prospective cohort study of children on ECMO, we assessed a panel of plasma brain injury biomarkers using exploratory factor analysis (EFA) to evaluate their interplay and association with outcomes. Biomarker concentrations were measured daily for the first 3 days of ECMO support in 95 participants. Unfavorable composite outcome was defined as in-hospital mortality or discharge Pediatric Cerebral Performance Category > 2 with decline ≥ 1 point from baseline. EFA grouped 11 biomarkers into three factors. Factor 1 comprised markers of cellular brain injury (NSE, BDNF, GFAP, S100ß, MCP1, VILIP-1, neurogranin); Factor 2 comprised markers related to vascular processes (vWF, PDGFRß, NPTX1); and Factor 3 comprised the BDNF/MMP-9 cellular pathway. Multivariable logistic models demonstrated that higher Factor 1 and 2 scores were associated with higher odds of unfavorable outcome (adjusted OR 2.88 [1.61, 5.66] and 1.89 [1.12, 3.43], respectively). Conversely, higher Factor 3 scores were associated with lower odds of unfavorable outcome (adjusted OR 0.54 [0.31, 0.88]), which is biologically plausible given the role of BDNF in neuroplasticity. Application of EFA on plasma brain injury biomarkers in children on ECMO yielded grouping of biomarkers into three factors that were significantly associated with unfavorable outcome, suggesting future potential as prognostic instruments.