AIMS: Glycoprotein acetyls (GlycA) is a biomarker of systemic inflammation and cardiovascular disease, yet little is known about its role in type 1 diabetes (T1D). We examined the associations among GlycA, central adiposity, insulin resistance, and early kidney injury in youth with T1D. METHODS: Glomerular filtration rate (GFR) and renal plasma flow (RPF) by iohexol and p-aminohippurate clearance, urine albumin-to-creatinine ratio (UACR), central adiposity by DXA, and estimated insulin sensitivity were assessed in fifty youth with T1D (16±3.0 years, 50% female, HbA(1c) 8.7±1.3%, T1D duration 5.7±2.6 years). Concentrations of GlycA were quantified by targeted nuclear magnetic resonance spectroscopy. Correlation and multivariable linear regression analyses were performed. RESULTS: GlycA was higher in girls vs. boys (1.05±0.26 vs. 0.84±0.15 mmol/L, p=0.001) and in participants who were overweight/obese vs. normal weight (1.12±0.23 vs. 0.87±0.20 mmol/L, p=0.0004). GlycA correlated positively with estimated intraglomerular pressure (r=0.52, p=0.001), UACR (r=0.53, p<0.0001) and trunk mass (r=0.45, p=0.001), and inversely with estimated insulin sensitivity (r:-0.36, p=0.01). All relationships remained significant after adjustment for age, sex, and HbA(1c). CONCLUSION: GlycA, a biomarker of inflammation, was higher in girls and those of overweight or obese body habitus in T1D. Additionally, GlycA associated with parameters of early kidney dysfunction, central adiposity, and insulin resistance.

Enterovirus D68 (EV-D68) causes cyclical outbreaks of respiratory disease and acute flaccid myelitis. EV-D68 is primarily transmitted through the respiratory route, but the duration of shedding in the respiratory tract is unknown. We prospectively enrolled 9 hospitalized children with EV-D68 respiratory infection and 16 household contacts to determine EV-D68 RNA shedding dynamics in the upper respiratory tract through serial midturbinate specimen collections and daily symptom diaries. Five (31.3%) household contacts, including 3 adults, were EV-D68-positive. The median duration of EV-D68 RNA shedding in the upper respiratory tract was 12 (range 7-15) days from symptom onset. The most common symptoms were nasal congestion (100%), cough (92.9%), difficulty breathing (78.6%), and wheezing (57.1%). The median illness duration was 20 (range 11-24) days. Understanding the duration of RNA shedding can inform the expected rate and timing of EV-D68 detection in associated acute flaccid myelitis cases and help guide public health measures.

AIMS: Elevated triglycerides (TG) are associated with development and progression of kidney disease, and TG distributions across lipoprotein subclasses predict kidney dysfunction in adults with type 1 diabetes (T1D). Little is known regarding these relationships in youth. METHODS: In this single center study conducted from October 2018-2019, lipid constituents from lipoprotein subclasses were quantified by targeted nuclear magnetic resonance spectroscopy. Glomerular filtration rate (GFR), renal plasma flow (RPF), afferent arteriolar resistance (R(A)), efferent arteriolar resistance (R(E)), intraglomerular pressure (P(GLO)), urine albumin-to-creatinine ratio (UACR), and chitinase-3-like protein 1 (YKL-40), a marker of kidney tubule injury, were assessed. Cross-sectional relationships were assessed by correlation and multivariable linear regression (adjusted for age, sex, HbA1c) models. RESULTS: Fifty youth with T1D (age 16 ± 3 years, 50 % female, HbA1c 8.7 ± 1.3 %, T1D duration 5.7 ± 2.6 years) were included. Very-low-density lipoprotein (VLDL)-TG concentrations correlated and associated with intraglomerular hemodynamic function markers including GFR, P(GLO), UACR, as did small low-density lipoprotein (LDL)-TG and small high-density lipoprotein (HDL)-TG. YKL-40 correlated with all lipoprotein subclasses. CONCLUSION: TG within lipoprotein subclasses, particularly VLDL, associated with P(GLO,) GFR, albuminuria, and YKL-40. Lipid perturbations may serve as novel targets to mitigate early kidney disease.

BACKGROUND: We compared plasma metabolites of amino acid oxidation and the tricarboxylic acid (TCA) cycle in youth with and without type 1 diabetes mellitus (T1DM) and related the metabolites to glomerular filtration rate (GFR), renal plasma flow (RPF), and albuminuria. Metabolites associated with impaired kidney function may warrant future study as potential biomarkers or even future interventions to improve kidney bioenergetics. METHODS: Metabolomic profiling of fasting plasma samples using a targeted panel of 644 metabolites and an untargeted panel of 19,777 metabolites was performed in 50 youth with T1DM ≤ 10 years and 20 controls. GFR and RPF were ascertained by iohexol and p-aminohippurate clearance, and albuminuria calculated as urine albumin to creatinine ratio. Sparse partial least squares discriminant analysis and moderated t tests were used to identify metabolites associated with GFR and RPF. RESULTS: Adolescents with and without T1DM were similar in age (16.1 ± 3.0 vs. 16.1 ± 2.9 years) and BMI (23.4 ± 5.1 vs. 22.7 ± 3.7 kg/m(2)), but those with T1DM had higher GFR (189 ± 40 vs. 136 ± 22 ml/min) and RPF (820 ± 125 vs. 615 ± 65 ml/min). Metabolites of amino acid oxidation and the TCA cycle were significantly lower in adolescents with T1DM vs. controls, and the measured metabolites were able to discriminate diabetes status with an AUC of 0.82 (95% CI: 0.71, 0.93) and error rate of 0.21. Lower glycine (r:-0.33, q = 0.01), histidine (r:-0.45, q < 0.001), methionine (r: -0.29, q = 0.02), phenylalanine (r: -0.29, q = 0.01), serine (r: -0.42, q < 0.001), threonine (r: -0.28, q = 0.02), citrate (r: -0.35, q = 0.003), fumarate (r: -0.24, q = 0.04), and malate (r: -0.29, q = 0.02) correlated with higher GFR. Lower glycine (r: -0.28, q = 0.04), phenylalanine (r:-0.3, q = 0.03), fumarate (r: -0.29, q = 0.04), and malate (r: -0.5, q < 0.001) correlated with higher RPF. Lower histidine (r: -0.28, q = 0.02) was correlated with higher mean ACR. CONCLUSIONS: In conclusion, adolescents with relatively short T1DM duration exhibited lower plasma levels of carboxylic acids that associated with hyperfiltration and hyperperfusion. TRIAL REGISTRATION: ClinicalTrials.gov NCT03618420 and NCT03584217 A higher resolution version of the Graphical abstract is available as Supplementary information.

OBJECTIVE: We examined changes in the excretion of various amino acids and in glycolysis and ketogenesis-related metabolites, during and after diabetic ketoacidosis (DKA) diagnosis, in youth with known or new onset type 1 diabetes (T1D). METHODS: Urine samples were collected from 40 youth with DKA (52% boys, mean age 114years, venous pH7.20.1, blood glucose 451163mg/dL) at 3 time points: 0-8h and 12-24h after starting an insulin infusion, and 3months after hospital discharge. Mixed-effects models evaluated the changes in amino acids and other metabolites in the urine. RESULTS: Concentrations of urine histidine, threonine, tryptophan, and leucine per creatinine were highest at 0-8h (148.823.5, 59.512.3, 15.41.4, and 24.52.4% of urine creatinine, respectively), and significantly decreased over 3months (p=0.028, p=0.027, p=0.019, and p<0.0001, respectively). Urine histidine, threonine, tryptophan, and leucine per urine creatinine decreased by 10.619.2, 0.70.9, 1.30.9, and 0.50.3-fold, respectively, between 0 and 8h and 3months. CONCLUSIONS: In our study, DKA was associated with profound aminoaciduria, suggestive of proximal tubular dysfunction analogous to Fanconi syndrome.

IMPORTANCE: Appropriately established pediatric reference intervals are critical to the clinical decision-making process and should reflect the physiologic changes that occur during healthy child development. Reference intervals used in pediatric care today remain highly inconsistent across a broad range of common clinical biomarkers. OBSERVATIONS: This narrative review assesses biomarker-specific pediatric reference intervals and their clinical utility with respect to the underlying biological changes occurring during development. Pediatric reference intervals from PubMed-indexed articles published from January 2015 to April 2021, commercial laboratory websites, study cohorts, and pediatric reference interval books were all examined. Although large numbers of pediatric reference intervals are published for some biomarkers, very few are used by clinical and commercial laboratories. The patterns, extent, and timing of biomarker changes are highly variable, particularly during developmental stages with rapid physiologic changes. However, many pediatric reference intervals do not capture these changes and thus do not accurately reflect the underlying biochemistry of development, resulting in significant inconsistencies between reference intervals. CONCLUSIONS AND RELEVANCE: There is a need to correctly describe the biochemistry of child development as well as to identify strategies to develop accurate and consistent pediatric reference intervals for improved pediatric care.

OBJECTIVE: Glomerular injury is a recognized complication of diabetic ketoacidosis (DKA), yet the tubular lesions are poorly understood. The aim of this prospective study was to evaluate the presence and reversibility of tubular injury during DKA in children with type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS: Blood and urine samples were collected from 40 children with DKA (52% boys, mean age 11 ± 4 years, venous pH 7.2 ± 0.1, glucose 451 ± 163 mg/dL) at three timepoints: 0-8 and 12-24 h after starting insulin, and 3 months after discharge. Mixed-effects models evaluated the changes in tubular injury markers over time (neutrophil gelatinase-associated lipocalin [NGAL], kidney injury molecule 1 [KIM-1], and interleukin 18 [IL-18]). We also evaluated the relationships among the tubular injury biomarkers, copeptin, a vasopressin surrogate, and serum uric acid (SUA). RESULTS: Serum NGAL, KIM-1, and IL-18 were highest at 0-8 h (306.5 ± 45.9 ng/mL, 128.9 ± 10.1 pg/mL, and 564.3 ± 39.2 pg/mL, respectively) and significantly decreased over 3 months (p = 0.03, p = 0.01, and p < 0.001, respectively). There were strong relationships among increases in copeptin and SUA and rises in tubular injury biomarkers. At 0-8 h, participants with acute kidney injury (AKI) [17%] showed significantly higher concentrations of tubular injury markers, copeptin, and SUA. CONCLUSIONS: DKA was characterized by tubular injury, and the degree of injury associated with elevated copeptin and SUA. Tubular injury biomarkers, copeptin and SUA may be able to predict AKI in DKA.

OBJECTIVE: To assess trends in racial disparity in supine sleep positioning across racial/ethnic groups of early preterm (EPT;<34 weeks) and late preterm (LPT;34-36 weeks) infants from 2000-2015. STUDY DESIGN: We analyzed Pregnancy Risk Assessment Monitoring System (PRAMS) data (a population-based perinatal surveillance system) from 16 U.S. states from 2000 to 2015 (Weighted N=1,020,986). Marginal prevalence of SSP by year was estimated for EPT and LPT infants, adjusting for maternal and infant characteristics. After stratifying EPT and LPT infants, adjusted odds of SSP trends were compared across racial/ethnic groups by testing the time-race interaction. RESULTS: From 2000 to 2015, Non-Hispanic Black infants had lower odds of SSP compared with Non-Hispanic White infants for EPT (AOR:0.61;95% CI 0.47-0.78) and LPT (AOR:0.44;95% CI:0.34-0.56) groups. For Hispanic infants, there was no statistically significant difference for either preterm group when compared with Non-Hispanic White infants. Adjusted odds of supine sleep positioning increased (on average) annually by 10.0%,7.3% and 7.7% respectively in Non-Hispanic White, Non-Hispanic Black, and Hispanic EPT infants and by 5.8%,5.9%, and 4.8% among Non-Hispanic White, Non-Hispanic Black, and Hispanic LPT infants. However, there were no significant between-group differences in annual changes (EPT:p=0.11; LPT:p=0.25). CONCLUSIONS: Supine sleep positioning increased for all racial/ethnic preterm groups from 2000 to 2015. However, the racial/ethnic disparity in supine sleep positioning among EPT and LPT groups persists.

The objective of this study was to compare the ratio of renal oxygen availability (RO(2)) to glomerular filtration rate (GFR), a measure of relative renal hypoxia, in adolescents with and without type 1 diabetes (T1D) and relate the ratio to albuminuria, renal plasma flow (RPF), fat mass, and insulin sensitivity (M/I). RO(2) was estimated by blood oxygen level-dependent MRI; fat mass was estimated by DXA; GFR and RPF were estimated by iohexol and p-aminohippurate clearance; albuminuria was estimated by urine albumin-to-creatinine ratio (UACR); and M/I was estimated from steady-state glucose infusion rate/insulin (mg/kg/min) by hyperglycemic clamp in 50 adolescents with T1D (age 16.1 ± 3.0 years, HbA(1c) 8.6 ± 1.2%) and 20 control patients of similar BMI (age 16.1 ± 2.9 years, HbA(1c) 5.2 ± 0.2%). The RO(2):GFR (ms/mL/min) was calculated as RO(2) (T2*, ms) divided by GFR (mL/min). Whole-kidney RO(2):GFR was 25% lower in adolescents with T1D versus control patients (P < 0.0001). In adolescents with T1D, lower whole-kidney RO(2):GFR was associated with higher UACR (r = -0.31, P = 0.03), RPF (r = -0.52, P = 0.0009), and fat mass (r = -0.33, P = 0.02). Lower medullary RO(2):GFR was associated with lower M/I (r = 0.31, P = 0.03). In conclusion, adolescents with T1D exhibited relative renal hypoxia that was associated with albuminuria and with increased RPF, fat mass, and insulin resistance. These data suggest a potential role of renal hypoxia in the development of diabetic kidney disease.

During the Ebola virus outbreak of 2013-2016, the Viral Special Pathogens Branch field laboratory in Sierra Leone tested approximately 26 000 specimens between August 2014 and October 2015. Analysis of the B2M endogenous control Ct values showed its utility in monitoring specimen quality, comparing results with different specimen types, and interpretation of results. For live patients, blood is the most sensitive specimen type and oral swabs have little diagnostic utility. However, swabs are highly sensitive for diagnostic testing of corpses.

In August 2014, the Viral Special Pathogens Branch of the US Centers for Disease Control and Prevention established a field laboratory in Sierra Leone in response to the ongoing Ebola virus outbreak. Through March 2015, this laboratory tested >12 000 specimens from throughout Sierra Leone. We describe the organization and procedures of the laboratory located in Bo, Sierra Leone.

INTRODUCTION: Recurrent venous thromboembolism (VTE) occurs infrequently following a provoked event but occurs in up to 30% of individuals following an initial unprovoked event. There is limited understanding of the biological mechanisms that predispose patients to recurrent VTE. OBJECTIVES: To identify whole blood gene expression profiles that distinguished patients with clinically distinct patterns of VTE. PATIENTS/METHODS: We studied 107 patients with VTE separated into 3 groups: (1) 'low-risk' patients had one or more provoked VTE; (2) 'moderate-risk' patients had a single unprovoked VTE; (3) 'high-risk' patients had ≥2 unprovoked VTE. Each patient group was also compared to twenty-five individuals with no personal history of VTE. Total RNA from whole blood was isolated and hybridized to Illumina HT-12V4 Beadchips to assay whole genome expression. RESULTS: Using class prediction analysis, we distinguished high-risk patients from low-risk patients and healthy controls with good receiver operating curve characteristics (AUC=0.81 and 0.84, respectively). We also distinguished moderate-risk individuals and low-risk individuals from healthy controls with AUC's of 0.69 and 0.80, respectively. Using differential expression analysis, we identified several genes previously implicated in thrombotic disorders by genetic analyses, including SELP, KLKB1, ANXA5, and CD46. Protein levels for several of the identified genes were not significantly different between the different groups. CONCLUSION: Gene expression profiles are capable of distinguishing patients with different clinical presentations of VTE, and genes relevant to VTE risk are frequently differentially expressed in these comparisons.

Genetic diversity at the human beta-globin locus has been implicated as a modifier of sickle cell anaemia (SCA) severity. However, haplotypes defined by restriction fragment length polymorphism sites across the beta-globin locus have not been consistently associated with clinical phenotypes. To define the genetic structure at the beta-globin locus more thoroughly, we performed high-density single nucleotide polymorphism (SNP) mapping in 820 children who were homozygous for the sickle cell mutation (HbSS). Genotyping results revealed very high linkage disequilibrium across a large region spanning the locus control region and the HBB (beta-globin gene) cluster. We identified three predominant haplotypes accounting for 96% of the betaS -carrying chromosomes in this population that could be distinguished using a minimal set of common SNPs. Consistent with previous studies, fetal haemoglobin level was significantly associated with betaS -haplotypes. After controlling for covariates, an association was detected between haplotype and rate of hospitalization for acute chest syndrome (ACS) (incidence rate ratio 0.51, 95% confidence interval 0.29-0.89) but not incidence rate of vaso-occlusive pain or presence of silent cerebral infarct (SCI). Our results suggest that these SNP-defined betaS -haplotypes may be associated with ACS, but not pain or SCI in a study population of children with SCA.

BACKGROUND: Parvovirus B19 (B19V) is a small, nonenveloped virus that typically causes a benign flu-like illness that occurs most frequently in childhood. The virus is resistant to current viral inactivation steps used in the manufacture of antihemophilic factor concentrates and B19V transmission through these products has been documented. Since 2000, B19V nucleic acid test (NAT) screening of plasma pools has been implemented to further decrease the viral burden in these products, but no study has examined populations using these products to assess the impact of the screening on B19V transmission. STUDY DESIGN AND METHODS: Blood specimens obtained from participants of a surveillance system established in federally supported specialized bleeding disorders clinics were used in a B19V seroprevalence study. RESULTS: A total of 1643 specimens from 1043 participants age 2 to 7 years born after B19V NAT screening was implemented were tested. Age-specific prevalence rates were generally higher for subjects exposed to either plasma-derived products alone or in combination with other products compared to subjects with no exposure to antihemophilic products. Overall, compared to participants unexposed to blood or blood products, those exposed to plasma-derived products alone were 1.7 times more likely to have antibodies to B19V (p = 0.002). CONCLUSION: These results are consistent with continued B19V transmission through plasma-derived factor concentrates. Effective viral inactivation and detection processes are needed to protect users of these products from infection with B19V or other new or emerging viruses.

Gajardo and colleagues1 contend that our finding of continued increased prevalence of parvovirus B19 (B19V) antibodies among users of plasma-derived factor concentrates relative to people with bleeding disorders unexposed to any blood or factor product2 may have been influenced by exposure to product not subjected to B19V nucleic acid test (NAT) screening or to exposure to low-purity products during the study period. The authors also disagree with our characterization of B19V as resistant to viral inactivation steps used in the manufacture of antihemophilic factor concentrates. | We understand and discuss in our article that B19V NAT screening was not initiated at the same time for all products. Nonetheless, we provided evidence, based on our finding of higher B19V prevalence in later years of the study period, that our findings were not likely due to transmissions that occurred solely in earlier years. For example, among 2- to 4-year-old children exposed to plasma-derived products, 77% of the specimens tested were drawn between 2006 and 2009—well after studies showed relatively complete adoption of screening.3 Others have reported the detection of B19V in products purchased in 2008.4 | The authors suggest that our study findings may also have been influenced by users of less highly purified products such as activated prothrombin complex concentrates. However, only 7% of subjects in our study were exposed to these products.

Salt sensitivity, the heterogeneity in the response of blood pressure (BP) to alterations in sodium intake, has been studied extensively, whereas weight sensitivity, the heterogeneity in BP response to weight change, has received scant attention. We examined the relationship of 21 gene polymorphisms previously found to be associated with hypertension, diabetes mellitus, or obesity, with weight sensitivity in the Trial of Nonpharmacologic Interventions in the Elderly, where participants with hypertension were randomized to receive intensive dietary intervention of sodium reduction, weight loss, both, or attention control, whereas pharmacological therapy was kept constant. After correcting for multiplicity, we identified significant associations of 3 polymorphisms with weight sensitivity of systolic BP (rs4646994, rs2820037, and rs1800629) and 3 polymorphisms for diastolic BP (rs4646994, rs2820037, and rs5744292). A recursive partitioning algorithm selected the combination of rs4646994, rs1800629, rs1982073, and rs1800896 as the set associated with the highest weight sensitivity. Polymorphisms related to hypertension, obesity, and diabetes mellitus are associated with weight sensitivity of BP.

Silent cerebral infarct (SCI) is the most commonly recognized cause of neurological injury in sickle cell anaemia (SCA). We tested the hypothesis that magnetic resonance angiography (MRA)-defined vasculopathy is associated with SCI. Furthermore, we examined genetic variations in glucose-6-phosphate dehydrogenase (G6PD) and HBA (alpha-globin) genes to determine their association with intracranial vasculopathy in children with SCA. Magnetic resonance imaging (MRI) of the brain and MRA of the cerebral vasculature were available in 516 paediatric patients with SCA, enrolled in the Silent Infarct Transfusion (SIT) Trial. All patients were screened for G6PD mutations and HBA deletions. SCI were present in 41.5% (214 of 516) of SIT Trial children. The frequency of intracranial vasculopathy with and without SCI was 15.9% and 6.3%, respectively (P < 0.001). Using a multivariable logistic regression model, only the presence of a SCI was associated with increased odds of vasculopathy (P = 0.0007, odds ratio (OR) 2.84; 95% Confidence Interval (CI) = 1.55-5.21). Among male children with SCA, G6PD status was associated with vasculopathy (P = 0.04, OR 2.78; 95% CI = 1.04-7.42), while no significant association was noted for HBA deletions. Intracranial vasculopathy was observed in a minority of children with SCA, and when present, was associated with G6PD status in males and SCI.

Sickle cell disease (SCD) is a common hemolytic disorder with a broad range of complications, including vaso-occlusive episodes, acute chest syndrome (ACS), pain, and stroke. Heme oxygenase-1 (gene HMOX1; protein HO-1) is the inducible, rate-limiting enzyme in the catabolism of heme and might attenuate the severity of outcomes from vaso-occlusive and hemolytic crises. A (GT)(n) dinucleotide repeat located in the promoter region of the HMOX1 gene is highly polymorphic, with long repeat lengths linked to decreased activity and inducibility. We examined this polymorphism to test the hypothesis that short alleles are associated with a decreased risk of adverse outcomes (hospitalization for pain or ACS) among a cohort of 942 children with SCD. Allele lengths varied from 13 to 45 repeats and showed a trimodal distribution. Compared with children with longer allele lengths, children with two shorter alleles (4%; ≤25 repeats) had lower rates of hospitalization for ACS (incidence rate ratio 0.28, 95% confidence interval: 0.10-0.81), after adjusting for sex, age, asthma, percentage of fetal hemoglobin and alpha-globin gene deletion. No relationship was identified between allele lengths and pain rate. We provide evidence that genetic variation in HMOX1 is associated with decreased rates of hospitalization for ACS, but not pain. This study is registered at www.ClinicalTrails.gov (NCT00072761).