The Puerto Rican Infant Metagenomic and Epidemiologic Study of Respiratory Outcomes (PRIMERO): Design and Baseline Characteristics for a Birth Cohort Study of Early-life Viral Respiratory Illnesses and Airway Dysfunction in Puerto Rican Children

Epidemiologic studies demonstrate an association between early-life respiratory illnesses (RIs) and the development of childhood asthma. However, it remains uncertain whether these children are predisposed to both conditions or if early-life RIs induce alterations in airway function, immune responses, or other human biology that contribute to the development of asthma. Puerto Rican children experience a disproportionate burden of early-life RIs and asthma, making them an important population for investigating this complex interplay. PRIMERO, the Puerto Rican Infant Metagenomics and Epidemiologic Study of Respiratory Outcomes , recruited pregnant women and their newborns to investigate how the airways develop in early life among infants exposed to different viral RIs, and will thus provide a critical understanding of childhood asthma development. As the first asthma birth cohort in Puerto Rico, PRIMERO will prospectively follow 2,100 term healthy infants. Collected samples include post-term maternal peripheral blood, infant cord blood, the child's peripheral blood at the year two visit, and the child's nasal airway epithelium, collected using minimally invasive nasal swabs, at birth, during RIs over the first two years of life, and at annual healthy visits until age five. Herein, we describe the study's design, population, recruitment strategy, study visits and procedures, and primary outcomes.

Breathing zone pollutant levels are associated with asthma exacerbations in high-risk children

Background

Indoor and outdoor air pollution levels are associated with poor asthma outcomes in children. However, few studies have evaluated whether breathing zone pollutant levels associate with asthma outcomes.

Objective

Determine breathing zone exposure levels of NO 2 , O 3 , total PM 10 and PM 10 constituents among children with exacerbation-prone asthma, and examine correspondence with in-home and community measurements and associations with outcomes.

Methods

We assessed children's personal breathing zone exposures using wearable monitors. Personal exposures were compared to in-home and community measurements and tested for association with lung function, asthma control, and asthma exacerbations.

Results

81 children completed 219 monitoring sessions. Correlations between personal and community levels of PM 10 , NO 2 , and O 3 were poor, whereas personal PM 10 and NO 2 levels correlated with in-home measurements. However, in-home monitoring underdetected brown carbon (Personal:79%, Home:36.8%) and ETS (Personal:83.7%, Home:4.1%) personal exposures, and detected black carbon in participants without these personal exposures (Personal: 26.5%, Home: 96%). Personal exposures were not associated with lung function or asthma control. Children experiencing an asthma exacerbation within 60 days of personal exposure monitoring had 1.98, 2.21 and 2.04 times higher brown carbon (p<0.001), ETS (p=0.007), and endotoxin (p=0.012), respectively. These outcomes were not associated with community or in-home exposure levels.

Conclusions

Monitoring pollutant levels in the breathing zone is essential to understand how exposures influence asthma outcomes, as agreement between personal and in-home monitors is limited. Inhaled exposure to PM 10 constituents modifies asthma exacerbation risk, suggesting efforts to limit these exposures among high-risk children may decrease their asthma burden.

CLINICAL IMPLICATIONS

In-home and community monitoring of environmental pollutants may underestimate personal exposures. Levels of inhaled exposure to PM 10 constituents appear to strongly influence asthma exacerbation risk. Therefore, efforts should be made to mitigate these exposures.

CAPSULE SUMMARY

Leveraging wearable, breathing-zone monitors, we show exposures to inhaled pollutants are poorly proxied by in-home and community monitors, among children with exacerbation-prone asthma. Inhaled exposure to multiple PM 10 constituents is associated with asthma exacerbation risk.

Genetic susceptibility for ischemic infarction and arteriolosclerosis based on neuropathologic evaluations

BACKGROUND

Recent genetic studies of stroke and related risk factors have identified a growing number of susceptibility loci; however, the relationship of these alleles to ischemic stroke is unknown. The challenge in finding reproducible loci of ischemic stroke susceptibility may be in part related to the etiologic heterogeneity in clinically defined stroke subtypes. In this study, we tested whether known single nucleotide polymorphisms (SNPs) associated with stroke or putative stroke risk factors are associated with neuropathologically defined micro- or macroscopic infarcts and with arteriolosclerosis.

METHODS

Measures of neuropathology and genotyping were available from 755 deceased participants from the Religious Orders Study and the Rush Memory and Aging Project. All donated brains were examined by a board-certified neuropathologist using standardized protocol for the presence of microscopic infarct, macroscopic infarct and arteriolosclerosis (lipohyalinosis). In primary analysis, 74 candidate SNPs previously associated (p < 5 × 10(-8)) with ischemic stroke or known risk factors, including atrial fibrillation (AF), hypertension, diabetes, low-density lipoprotein (LDL) level and carotid artery stenosis, were evaluated for association with neuropathologic endpoints. We performed a secondary exploratory analysis to include 93 additional SNPs associated with putative ischemic stroke risk factors including SNPs associated with high-density lipoprotein (HDL), triglyceride serum levels, myocardial infarction (MI), coronary artery disease and cerebral white matter disease. Regression models relating SNPs to cerebrovascular neuropathology were adjusted for age at death, gender and cohort membership.

RESULTS

The strongest associations seen for both macroscopic and microscopic infarcts were risk variants associated with diabetes. The diabetes risk variant rs7578326 located near the IRS1 locus was associated with both macroscopic (OR = 0.73, p = 0.011) and microscopic (OR = 0.71, p = 0.009) infarct pathology. Another diabetes susceptibility locus (rs12779790) located between the calcium/calmodulin-dependent protein kinase ID (CAMK1D) and cell division cycle 123 homolog (CDC123) genes is also associated with both macroscopic (OR = 1.40, p = 0.0292) and microscopic infarcts (OR = 1.43, p = 0.0285). The diabetes risk variant rs864745 within JAZF1 was associated with arteriolosclerosis (OR = 0.80, p = 0.014). We observed suggestive associations with the diabetes risk variant rs7961581 (p = 0.038; between TSPAN8 and LGR5) and rs5215 (p = 0.043; KCNJ11), the LDL risk variant rs11206510 (p = 0.045; PCSK9), as well as the AF risk locus ZFHX3. The CDKN2A/B locus (rs2383207, 9p21), identified initially as a susceptibility allele for MI and recently implicated in large vessel stroke, was associated with macroscopic infarct pathology in our autopsy cohort (OR = 1.26, p = 0.031).

CONCLUSION

Our results suggest replication of the candidate CDKN2A/B stroke susceptibility locus with directly measured macroscopic stroke neuropathology, and further implicate several diabetes and other risk variants with secondary, pleiotropic associations to stroke-related pathology in our autopsy cohort. When coupled with larger sample sizes, cerebrovascular neuropathologic phenotypes will likely be powerful tools for the genetic dissection of susceptibility for ischemic stroke.

Abstract TP426: Candidate CSF Cytokine and Chemokine Biomarkers for Vasospasm and Poor Outcome in Human Subarachnoid Hemorrhage

Introduction: Growing evidence suggest inflammation plays a key role in the pathogenesis of vasospasm (VSP) and secondary ischemic injury following subarachnoid hemorrhage (SAH). While elevations of select pro-inflammatory cytokines such interleukin (IL) 6 in cerebrospinal fluid (CSF) are linked to VSP in SAH, it is unclear which cytokines are measurable in SAH CSF. We explore a panel of cytokines and chemokines during peak VSP time window in human SAH in search for novel CSF biomarkers.

Methods: CSF samples were collected through external ventricular drain from a prospective SAH cohort. Clinical outcome was evaluated at 3- and 6-months using modified Rankin scores (mRS). Poor outcome was defined as mRS>2. Angiographic VSP was defined as >50% reduction in caliber of any vessel on post-SAH day 7 cerebral angiogram. In 29 SAH subjects, we compared post-SAH day 5 CSF biomarker profile with respect to outcome and VSP using Milliplex panel (EMD Millipore) with 42 biomarkers. Continuous variables were compared using Wilcoxon rank sum test. Benjamin-Hochberg correction was used for multiple comparisons.

Results: VSP occurred in 45% of the SAH cohort, and 52% of this cohort had good outcome at 3 month. Of the 42 biomarkers, 39 were measurable in SAH CSF. Elevated CSF IL-4 showed strongest trend towards association with good outcome at 3-month (p=0.0049) and at 6-months (p=0.02). Other CSF biomarkers showing trend toward association with outcome include epidermal growth factor (p=0.035), fractalkine (p=0.045), and platelet-derived growth factor AA (p=0.024). Elevation of a different cluster of biomarkers showed trend towards association with VSP: IL-5 (p=0.041), IL-17A (p=0.049), and IL-2 (p=0.047). No single marker reached significance at p<0.05 level after adjustment for multiple comparisons.

Conclusions: Differential expression of cytokine and chemokines are present in CSF post SAH. Results from this small pilot study suggest a possible association between elevation of CSF anti-inflammatory cytokine IL-4 and good SAH outcome. This is consistent with animal studies showing IL-4 attenuates ischemic injury and promotes neuroprotection. Larger targeted studies are necessary to investigate the role of cytokines and specifically CSF IL-4 in SAH outcome.