Respiratory Phenotype Research Articles

Respiratory phenotype and health care utilization patterns by adults with sickle cell disease

AbstractAdults with sickle cell disease (SCD) and asthma have increased mortality and health care utilization; however, there are individuals with respiratory symptoms (including cough and wheeze) without asthma. These individuals may have similar patterns of increased mortality and health care utilization. To characterize the association between respiratory phenotype and health care utilization by adults with SCD. Cross-sectional study of adults with SCD presenting for emergency and inpatient hospital care from 2012 to 2014 in Florida, Iowa, and New York using state-level health care utilization databases. Outcomes of interest include all-cause, SCD-related, painful episode, and acute chest syndrome–related care. Respiratory phenotype was defined as SCD + asthma, SCD + respiratory symptoms, and SCD + none. We built multivariable logistic regression and negative binomial regression models to evaluate the association adjusting for demographics, social determinant of health proxies, year of care, and state. Of 29 952 identified individuals, 3.4% had intermittent respiratory symptoms, and a larger proportion (15.6%) had asthma. There was a high rate of inpatient hospitalizations (43%) and ED visits (60%). Individuals with asthma had a higher annual risk of inpatient hospitalizations (48% vs 37%) but lower annual risk of an ED visit (62% vs 86%) than individuals with intermittent respiratory symptoms. The pattern of increased health care utilization among individuals with intermittent respiratory symptoms was consistent across each utilization type. In this large cohort of adults with SCD, we identified some with intermittent respiratory symptoms who had significantly increased health care utilization. This warrants further evaluation to understand potential etiologies and interventions.

Sensitisation to Lep d 2- Lepidoglyphus destructor allergy in asthma and rhinitis.

Background. Mites are responsible for allergic diseases, such as asthma and rhinitis, in nearly 1.5% of the world population. It is known that nowadays, besides House Dust Mites (HDM), Storage Mites (SM) are important sensitisers in urban non-occupational dwellings, predominantly in the Mediterranean area. The main objective of our study was to analyse the clinical relevance of the most prevalent SM, Lepidoglyphus destructor, by assessing the relationship between sensitisation to the major molecular allergen Lep d 2 and allergic respiratory disease phenotype in an urban population monosensitised to this molecular allergen. Methods. Cross-sectional study which included consecutive patients evaluated in our Allergy Department between 2012 and 2018, from urban non-occupational setting, with rhinitis and/or asthma, perennial symptoms and proven sensitisation to SM Lep d 2, tested using ImmunoCAP Immuno Solid-phase Allergen Chip (ISAC) technology, which detects 112 allergens. Results. A total of 37 allergic patients were included (23 female), aged 20.1 ± 12.8, min-max 5-58 years-old. The molecular sensitisation profile showed 18.9% of L. destructor mite monosensitised patients, having only sIgE to Lep d 2. This subset of patients mainly had allergic rhinitis, with 28.6% also being asthmatic. Regarding severity, most patients showed a persistent moderate phenotype of respiratory disease. The mean value of Lep d 2 sIgE was 8.3 ± 9.8 ISU-E, lower than in mite polysensitised patients (21.7 ± 21.5, p = 0.049). Conclusions. Our proof-of-concept study focused on Lep d 2 monosensitisation, showed that SM may have clinical relevance in perennial allergic asthma and rhinitis, and should be taken into account when assessing and treating allergic respiratory disease. Conclusions. The present survey demonstrated that Italian primary care pediatricians accomplish ARIA guidelines and adapt treatment on the basis of the intensity of symptoms. Corticosteroids and antihistamines are the most common prescribed medications. Nasal lavages are also popular.

Derivation and validation of generalized sepsis-induced acute respiratory failure phenotypes among critically ill patients: a retrospective study

BackgroundSeptic patients who develop acute respiratory failure (ARF) requiring mechanical ventilation represent a heterogenous subgroup of critically ill patients with widely variable clinical characteristics. Identifying distinct phenotypes of these patients may reveal insights about the broader heterogeneity in the clinical course of sepsis, considering multi-organ dynamics. We aimed to derive novel phenotypes of sepsis-induced ARF using observational clinical data and investigate the generalizability of the derived phenotypes.MethodsWe performed a multi-center retrospective study of ICU patients with sepsis who required mechanical ventilation for ≥ 24 h. Data from two different high-volume academic hospital centers were used, where all phenotypes were derived in MICU of Hospital-I (N = 3225). The derived phenotypes were validated in MICU of Hospital-II (N = 848), SICU of Hospital-I (N = 1112), and SICU of Hospital-II (N = 465). Clinical data from 24 h preceding intubation was used to derive distinct phenotypes using an explainable machine learning-based clustering model interpreted by clinical experts.ResultsFour distinct ARF phenotypes were identified: A (severe multi-organ dysfunction (MOD) with a high likelihood of kidney injury and heart failure), B (severe hypoxemic respiratory failure [median P/F = 123]), C (mild hypoxia [median P/F = 240]), and D (severe MOD with a high likelihood of hepatic injury, coagulopathy, and lactic acidosis). Patients in each phenotype showed differences in clinical course and mortality rates despite similarities in demographics and admission co-morbidities. The phenotypes were reproduced in external validation utilizing the MICU of Hospital-II and SICUs from Hospital-I and -II. Kaplan–Meier analysis showed significant difference in 28-day mortality across the phenotypes (p < 0.01) and consistent across MICU and SICU of both Hospital-I and -II. The phenotypes demonstrated differences in treatment effects associated with high positive end-expiratory pressure (PEEP) strategy.ConclusionThe phenotypes demonstrated unique patterns of organ injury and differences in clinical outcomes, which may help inform future research and clinical trial design for tailored management strategies.

Validation of an acute respiratory infection phenotyping algorithm to support robust computerised medical record-based respiratory sentinel surveillance, England, 2023.

IntroductionRespiratory sentinel surveillance systems leveraging computerised medical records (CMR) use phenotyping algorithms to identify cases of interest, such as acute respiratory infection (ARI). The Oxford-Royal College of General Practitioners Research and Surveillance Centre (RSC) is the English primary care-based sentinel surveillance network.AimThis study describes and validates the RSC's new ARI phenotyping algorithm.MethodsWe developed the phenotyping algorithm using a framework aligned with international interoperability standards. We validated our algorithm by comparing ARI events identified during the 2022/23 influenza season in England through use of both old and new algorithms. We compared clinical codes commonly used for recording ARI.ResultsThe new algorithm identified an additional 860,039 cases and excluded 52,258, resulting in a net increase of 807,781 cases (33.84%) of ARI compared to the old algorithm, with totals of 3,194,224 cases versus 2,386,443 cases. Of the 860,039 newly identified cases, the majority (63.7%) were due to identification of symptom codes suggestive of an ARI diagnosis not detected by the old algorithm. The 52,258 cases incorrectly identified by the old algorithm were due to inadvertent identification of chronic, recurrent, non-infectious and other non-ARI disease.ConclusionWe developed a new ARI phenotyping algorithm that more accurately identifies cases of ARI from the CMR. This will benefit public health by providing more accurate surveillance reports to public health authorities. This new algorithm can serve as a blueprint for other CMR-based surveillance systems wishing to develop similar phenotyping algorithms.

A Neural Basis for Mutant ATAXIN-1 Induced Respiratory Dysfunction in Mouse Models of Spinocerebellar Ataxia Type 1.

Spinocerebellar ataxia type 1 (SCA1), a dominantly inherited neurodegenerative disorder caused by an expanded trinucleotide repeat in the ATAXIN-1 (ATXN1) gene, is characterized by motor dysfunction, cognitive impairment, and death from compromised swallowing and respiration. To delineate specific cell types that contribute to respiratory dysfunction, we utilized the floxed conditional knock-in f-ATXN1 146Q/2Q mouse. Whole body plethysmography during spontaneous respiration and respiratory challenge showed that f-ATXN1 146Q/2Q mice exhibit a spontaneous respiratory phenotype characterized by elevated respiratory frequency, volumes, and respiratory output. Consequently, the ability of f-ATXN1 146Q/2Q mice to increase ventilation during the challenge is impaired. To investigate the role of mutant ATXN1 expression in neural and skeletal muscle lineages, f-ATXN1 146Q/2Q mice were bred to Nestin-Cre and Acta1-Cre mice respectively. These analyses revealed that the abnormal spontaneous respiration in f-ATXN1 146Q/2Q mice involved two aspects: a behavioral phenotype in which SCA1 mice exhibit increased motor activity during respiratory testing and functional dysregulation of central respiratory control centers. Both aspects of spontaneous respiration were partially ameliorated by removing mutant ATXN1 from neural, but not skeletal muscle, cell lineages.

Cardiolipin remodeling maintains the inner mitochondrial membrane in cells with saturated lipidomes

Cardiolipin (CL) is a unique, four-chain phospholipid synthesized in the inner mitochondrial membrane (IMM). The acyl chain composition of CL is regulated through a remodeling pathway, whose loss causes mitochondrial dysfunction in Barth syndrome (BTHS). Yeast has been used extensively as a model system to characterize CL metabolism, but mutants lacking its two remodeling enzymes, Cld1p and Taz1p, exhibit mild structural and respiratory phenotypes compared to mammalian cells. Here, we show an essential role for CL remodeling in the structure and function of the IMM in yeast grown under reduced oxygenation. Microaerobic fermentation, which mimics natural yeast environments, caused the accumulation of saturated fatty acids and, under these conditions, remodeling mutants showed a loss of IMM ultrastructure. We extended this observation to HEK293 cells, where phospholipase A2 inhibition by Bromoenol lactone resulted in respiratory dysfunction and cristae loss upon mild treatment with exogenous saturated fatty acids. In microaerobic yeast, remodeling mutants accumulated unremodeled, saturated CL, but also displayed reduced total CL levels, highlighting the interplay between saturation and CL biosynthesis and/or breakdown. We identified the mitochondrial phospholipase A1 Ddl1p as a regulator of CL levels, and those of its precursors phosphatidylglycerol and phosphatidic acid, under these conditions. Loss of Ddl1p partially rescued IMM structure in cells unable to initiate CL remodeling and had differing lipidomic effects depending on oxygenation. These results introduce a revised yeast model for investigating CL remodeling and suggest that its structural functions are dependent on the overall lipid environment in the mitochondrion.

Combined Exercise and Diet Induce Airway Hyperreactivity While Reducing Liver Steatosis in Mice with Diet-Induced Obesity.

Obesity is a multi-organ system disease, which is associated with, e.g., a higher prevalence of non-alcoholic fatty liver disease (NAFLD) and asthma. Little is known regarding the effect of obesity-related parameters (including liver integrity) and the respiratory phenotype after a combination of physical activity and diet. Thirty-two C57BL/6 mice were, after 27 weeks of a high fat diet (HFD), randomly assigned to two dietary interventions for three weeks: a HFD or a normal chow diet (NCD). In both dietary groups, half of the animals were subjected to a sub-maximal exercise protocol. Lung function, lung inflammation, liver histology, and metabolic profile were determined. Mice with obesity did not show airway hyperreactivity after methacholine provocation. Sub-maximal exercise with diet (NCD/E) induced a significant reduction in forced expiratory volume in 0.1 s after methacholine provocation. NCD/E had significantly more neutrophils and inflammation (IFN-γ, TNF-α, IL-4, and IL-17F) in bronchoalveolar lavage compared to non-exercising mice on a HFD (HFD/NE). However, more epithelial injury (serum surfactant protein D and IL-33) was seen in HFD/NE. Additionally, hepatic steatosis and fibrosis were reduced by combined diet and sub-maximal exercise. Combining sub-maximal exercise with diet induced airway hyperreactivity and pulmonary inflammation, while body weight, hepatic steatosis, and fibrosis improved.

Viral and non-viral episodes of wheezing in early life and the development of asthma and respiratory phenotypes among urban children.

Viral wheezing is an important risk factor for asthma, which comprises several respiratory phenotypes. We sought to understand if the etiology of early-life wheezing illnesses relates to childhood respiratory and asthma phenotypes. Data were collected prospectively on 429 children in the Urban Environment and Childhood Asthma (URECA) birth cohort study through age 10 years. We identified wheezing illnesses and the corresponding viral etiology (PCR testing of nasal mucus) during the first 3 years of life. Six phenotypes of respiratory health were identified at 10 years of age based on trajectories of wheezing, allergic sensitization, and lung function. We compared the etiology of early wheezing illnesses to these wheezing respiratory phenotypes and the development of asthma. In the first 3 years of life, at least one virus was detected in 324 (67%) of the 483 wheezing episodes documented in the study cohort. Using hierarchical partitioning we found that non-viral wheezing episodes accounted for the greatest variance in asthma diagnosed at both 7 and 10 years of age (8.0% and 5.8% respectively). Rhinovirus wheezing illnesses explained the most variance in respiratory phenotype outcome followed by non-viral wheezing episodes (4.9% and 3.9% respectively) at 10 years of age. Within this high-risk urban-residing cohort in early life, non-viral wheezing episodes were frequently identified and associated with asthma development. Though rhinovirus wheezing illnesses had the greatest association with phenotype outcome, the specific etiology of wheezing episodes in early life provided limited information about subsequent wheezing phenotypes.

Chronic changes in developmental oxygen have little effect on mitochondria and tracheal density in the endothermic moth Manduca sexta.

Oxygen availability during development is known to impact the development of insect respiratory and metabolic systems. Drosophila adult tracheal density exhibits developmental plasticity in response to hypoxic or hyperoxic oxygen levels during larval development. Respiratory systems of insects with higher aerobic demands, such as those that are facultative endotherms, may be even more responsive to oxygen levels above or below normoxia during development. The moth Manduca sexta is a large endothermic flying insect that serves as a good study system to start answering questions about developmental plasticity. In this study, we examined the effect of developmental oxygen levels (hypoxia: 10% oxygen, and hyperoxia: 30% oxygen) on the respiratory and metabolic phenotype of adult moths, focusing on morphological and physiological cellular and intercellular changes in phenotype. Mitochondrial respiration rate in permeabilized and isolated flight muscle was measured in adults. We found that permeabilized flight muscle fibers from the hypoxic group had increased mitochondrial oxygen consumption, but this was not replicated in isolated flight muscle mitochondria. Morphological changes in the trachea were examined using confocal imaging. We used transmission electron microscopy to quantify muscle and mitochondrial density in the flight muscle. The respiratory morphology was not significantly different between developmental oxygen groups. These results suggest that the developing M. sexta trachea and mitochondrial respiration have limited developmental plasticity when faced with rearing at 10% or 30% oxygen.

Genetic identification of medullary neurons underlying congenital hypoventilation.

Mutations in the transcription factors encoded by PHOX2B or LBX1 correlate with congenital central hypoventilation disorders. These conditions are typically characterized by pronounced hypoventilation, central apnea, and diminished chemoreflexes, particularly to abnormally high levels of arterial PCO2. The dysfunctional neurons causing these respiratory disorders are largely unknown. Here, we show that distinct, and previously undescribed, sets of medullary neurons coexpressing both transcription factors (dB2 neurons) account for specific respiratory functions and phenotypes seen in congenital hypoventilation. By combining intersectional chemogenetics, intersectional labeling, lineage tracing, and conditional mutagenesis, we uncovered subgroups of dB2 neurons with key functions in (i) respiratory tidal volumes, (ii) the hypercarbic reflex, (iii) neonatal respiratory stability, and (iv) neonatal survival. These data provide functional evidence for the critical role of distinct medullary dB2 neurons in neonatal respiratory physiology. In summary, our work identifies distinct subgroups of dB2 neurons regulating breathing homeostasis, dysfunction of which causes respiratory phenotypes associated with congenital hypoventilation.

Biallelic Variants in MNS1 Are Associated with Laterality Defects and Respiratory Involvement.

Defects in motile cilia, termed motile ciliopathies, result in clinical manifestations affecting the respiratory and reproductive system, as well as laterality defects and hydrocephalus. We previously defined biallelic MNS1 variants causing situs inversus and male infertility, mirroring the findings in Mns1-/- mice. Here, we present clinical and genomic findings in five newly identified individuals from four unrelated families affected by MNS1-related disorder. Ciliopathy panel testing and whole exome sequencing identified one previously reported and two novel MNS1 variants extending the genotypic spectrum of disease. A broad spectrum of laterality defects including situs inversus totalis and heterotaxia was confirmed. Interestingly, a single affected six-year-old girl homozygous for an MNS1 nonsense variant presented with a history of neonatal respiratory distress syndrome, recurrent respiratory tract infections, chronic rhinitis, and wet cough. Accordingly, immunofluorescence analysis showed the absence of MNS1 from the respiratory epithelial cells of this individual. Two other individuals with hypomorphic variants showed laterality defects and mild respiratory phenotype. This study represents the first observation of heterotaxia and respiratory disease in individuals with biallelic MNS1 variants, an important extension of the phenotype associated with MNS1-related motile ciliopathy disorder.

Tibetans exhibit lower hemoglobin concentration and decreased heart response to hypoxia during poikilocapnia at intermediate altitude relative to Han Chinese.

High-altitude populations exhibit distinct cellular, respiratory, and cardiovascular phenotypes, some of which provide adaptive advantages to hypoxic conditions compared to populations with sea-level ancestry. Studies performed in populations with a history of high-altitude residence, such as Tibetans, support the idea that many of these phenotypes may be shaped by genomic features that have been positively selected for throughout generations. We hypothesize that such traits observed in Tibetans at high altitude also occur in Tibetans living at intermediate altitude, even in the absence of severe sustained hypoxia. We studied individuals of high-altitude ancestry (Tibetans, n = 17 females; n = 12 males) and sea-level ancestry (Han Chinese, n = 6 females; n = 10 males), both who had been living at ∼1300m (∼4327ft) for at least 18 months. We measured hemoglobin concentration ([Hb]), hypoxic ventilatory response (HVR), and hypoxic heart rate response (HHRR) with end-tidal CO2 (PetCO2) held constant (isocapnia) or allowed to decrease with hypoxic hyperventilation (poikilocapnia). We also quantified the contribution of CO2 on ventilation and heart rate by calculating the differences of isocapnic versus poikilocapnic hypoxic conditions (Δ /ΔPetCO2 and ΔHR/ΔPetCO2, respectively). Male Tibetans had lower [Hb] compared to Han Chinese males (p < 0.05), consistent with reports for individuals from these populations living at high altitude and sea level. Measurements of ventilation (resting ventilation, HVR, and PetCO2) were similar for both groups. Heart rate responses to hypoxia were similar in both groups during isocapnia; however, HHRR in poikilocapnia was reduced in the Tibetan group (p < 0.03), and the heart rate response to CO2 in hypoxia was lower in Tibetans relative to Han Chinese (p < 0.01). These results suggest that Tibetans living at intermediate altitude have blunted cardiac responses in the context of hypoxia. Hence, only some of the phenotypes observed in Tibetans living at high altitude are observed in Tibetans living at intermediate altitude. Whereas blunted cardiac responses to hypoxia is revealed at intermediate altitudes, manifestation of other physiological adaptations to high altitude may require exposure to more severe levels of hypoxia.

Advanced Age Impairs the Neuromuscular Control of Peak Inspiratory Performance in Mice

Respiratory muscle wasting is known to occur in ageing adults resulting in a decreased capacity for force production and an associated reduction in high-threshold respiratory performance. Dysfunction of the respiratory musculature in this manner may contribute to an increased susceptibility to respiratory complications frequently observed in older populations. The objective of the current study was to characterise the respiratory phenotype during advanced age to assess the impact of sarcopenia on the neuromuscular control of respiratory performance. Male wild type (BL10) mice were studied at 6-months and 24-months, representing young and old age cohorts, respectively. In anaesthetised animals, inspiratory pressure and contemporaneous obligatory and accessory respiratory muscle electromyography (EMG) activities were measured during baseline and sustained tracheal occlusion (n = 9 young; n = 8 old). Diaphragm muscle contractile performance was assessed ex-vivo via tissue bath preparations (n = 8 young; n = 8 old). Furthermore, diaphragm and limb muscle tissues were harvested and snap frozen for subsequent structural and molecular analyses which will assess potential differences in cross-sectional area and relative fibre type composition. Peak inspiratory pressure was significantly reduced in 24-month-old compared to 6-month-old mice (P &lt; 0.0001). Associated EMG activity was significantly lower (P &lt; 0.05) in obligatory (external intercostal; parasternal) and accessory (cleidomastoid; scalene; trapezius; sternomastoid; sternohyoid) muscles of breathing in the old group compared to the young. Diaphragm EMG amplitude was not different between the groups. No differences were observed in the force-generating capacity of the diaphragm between young and old cohorts. Our preliminary results suggest an impairment in the neuromuscular control of the respiratory system during peak performance which apparently precedes the age-related decline in diaphragm muscle force generating capacity. Our further histological and molecular analyses will provide additional insight into the nature of this respiratory phenotype in advanced age. This work was funded by the Department of Physiology, UCC. B.T. Murphy is funded by an Irish Research Council Doctoral Scholarship. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The familial amyotrophic lateral sclerosis-associated A4V SOD1 mutant is not able to regulate aerobic glycolysis

Under certain stress conditions, astrocytes operate in aerobic glycolysis, a process controlled by pyruvate dehydrogenase (PDH) inhibition through its E1 α subunit (Pda1) phosphorylation. This supplies lactate to neurons, which save glucose to obtain NADPH to, among other roles, counteract reactive oxygen species. A failure in this metabolic cooperation causes severe damage to neurons. In this work, using humanized Saccharomyces cerevisiae cells in which its endogenous Cu/Zn Superoxide Dismutase (SOD1) was replaced by human ortholog, we investigated the role of human SOD1 (hSOD1) in aerobic glycolysis regulation and its implications to amyotrophic lateral sclerosis (ALS), a neurodegenerative disease. Yeast cells ferment glucose even in the presence of oxygen and switch to respiratory metabolism after glucose exhaustion. However, like cells of SOD1-knockout strain, cells expressing A4V mutant of hSOD1 growing on glucose showed a respiratory phenotype, i.e., low glucose and high oxygen consumptions and low intracellular oxidation levels in response to peroxide stress, contrary to cells expressing wild-type (WT) SOD1 (yeast or human). The A4V mutation in hSOD1 is linked to ALS. In contrast to WT SOD1 strains, PDH activity of both sod1Δ and A4V hSOD1 cells did not change in response to a metabolic shift toward oxidative metabolism, which was associated to lower Pda1 phosphorylation levels under growth on glucose. Taken together, our results suggest that A4V mutant cannot regulate aerobic glycolysis via Pda1 phosphorylation the same way WT hSOD1, which might be linked to problems observed in the motor neurons of ALS patients with the SOD1 A4V mutation.

The impact of repeat opioid use (ROU) on fentanyl-induced respiratory depression

Objective: Repeat opioid use (ROU) is a primary driver for the ongoing opioid epidemic, and while a substantial understanding exists for the impact of ROU on behavioral neurophysiology, the consequences of ROU on respiratory-related physiology including opioid-induced respiratory depression (OIRD) remain poorly understood. Hypothesis: ROU leads to respiratory tolerance to fentanyl that is characterized by the blunting of respiratory depression and improvement of O2 consumption (VO2). Methods: We utilized a pre-clinical rodent model. Breathing was measured via whole body-plethysmography in freely behaving adult mice (P&gt;90) prior to and immediately following fentanyl administration. A single dose of fentanyl (0.7 mg/kg, i.p.) was given for up to 6 consecutive days. In a subset of experiments, O2 consumption was measured simultaneously using whole-body plethysmography. Results: We identified two distinct respiratory phenotypes in response to OIRD following ROU. Type 1 phenotype (n=18) adapted over time where breathing during OIRD is greater on day 5 versus day 1. In contrast, the Type 2 phenotype (n=5) showed no such adaptation, with unchanged or worsened breathing by day 5. In a subset of animals (n=12) the relationship between breathing (i.e. minute ventilation (Ve)) and oxygen consumption (VO2) was examined before and following ROU. Under baseline conditions the Ve to VO2 relationship positively correlated on day 1 and 5. During OIRD on day 1 this correlation became negative, but began to normalize by day 5, resembling the baseline relationship. These phenomena also coincided with an increase in the ventilatory drive observed at the whole-animal level and in the isolated preBötzinger complex following ROU. Conclusions: ROU leads to two distinct respiratory phenotypes in response to OIRD, where the majority of subjects show a blunted respiratory depression. Additionally, ROU improves the relationship between breathing and oxygen consumption and enhances inspiratory drive in the presence of fentanyl. These findings suggest that fentanyl-induced hypoxia experienced by repeat opioid users vastly differ from naïve users. Such differences may contribute to the unpredictable occurrence of overdose amongst repeat users. This work was supported by NIH: R01 HL163965 and DA057767. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Proteomics, Human Environmental Exposure, and Cardiometabolic Risk.

The biological mechanisms linking environmental exposures with cardiovascular disease pathobiology are incompletely understood. We sought to identify circulating proteomic signatures of environmental exposures and examine their associations with cardiometabolic and respiratory disease in observational cohort studies. We tested the relations of >6500 circulating proteins with 29 environmental exposures across the built environment, green space, air pollution, temperature, and social vulnerability indicators in ≈3000 participants of the CARDIA study (Coronary Artery Risk Development in Young Adults) across 4 centers using penalized and ordinary linear regression. In >3500 participants from FHS (Framingham Heart Study) and JHS (Jackson Heart Study), we evaluated the prospective relations of proteomic signatures of the envirome with cardiovascular disease and mortality using Cox models. Proteomic signatures of the envirome identified novel/established cardiovascular disease-relevant pathways including DNA damage, fibrosis, inflammation, and mitochondrial function. The proteomic signatures of the envirome were broadly related to cardiometabolic disease and respiratory phenotypes (eg, body mass index, lipids, and left ventricular mass) in CARDIA, with replication in FHS/JHS. A proteomic signature of social vulnerability was associated with a composite of cardiovascular disease/mortality (1428 events; FHS: hazard ratio, 1.16 [95% CI, 1.08-1.24]; P=1.77×10-5; JHS: hazard ratio, 1.25 [95% CI, 1.14-1.38]; P=6.38×10-6; hazard ratio expressed as per 1 SD increase in proteomic signature), robust to adjustment for known clinical risk factors. Environmental exposures are related to an inflammatory-metabolic proteome, which identifies individuals with cardiometabolic disease and respiratory phenotypes and outcomes. Future work examining the dynamic impact of the environment on human cardiometabolic health is warranted.

0777 Respiratory Sleep Phenotypes in Prader-Willi Syndrome: Does the Type of Mutation Matter?

0777 Respiratory Sleep Phenotypes in Prader-Willi Syndrome: Does the Type of Mutation Matter?

Construction and characterization of a modA gene mutant strain of Klebsiella pneumoniae

To construct a mutant strain of Klebsiella pneumoniae NTUH- K2044 with modA gene deletion and its complementary strain and explore the role of modA gene in modulating anaerobic nitrate respiratory growth and phenotypes of K. pneumoniae. The modA deletion mutant K. pneumoniae strain was constructed by homologous recombination using the suicide vector pKO3-Km. To obtain the complementary strain C-modA, the whole sequence fragment containing the promoter, open reading frame and terminator regions of modA was cloned into pGEM-T-easy and electrically transformed into the modA deletion mutant. The NTUH-K2044 wild-type strain, modA gene deletion mutant and complementary strain were compared by measuring in vitro anaerobic nitrate respiration growth, competitiveness index, biofilm quantification, mucoviscosity assay and morphological measurement using Image J. The modA deletion mutant strain ΔmodA and the complementary strain C-modA were successfully constructed. The modA gene knockout strain showed inhibited anaerobic nitrate respiratory growth compared with the wild- type and C-modA strains with significantly weakened competitiveness, reduced capacity of biofilm synthesis during anaerobiosis, and lowered mucoviscosity under anaerobic conditions. The ΔmodA strain showed a spherical morphology in anaerobic conditions as compared with the normal short rod-like morphology of K. pneumoniae, with also distinctly shorter length than the wild-type and C-modA strains. The molybdate transport system encoding gene modA is associated with the pathogenic capacity of K. pneumoniae by modulating its anaerobic nitrate respiration, competitiveness, biofilm formation, hypermucoviscous phenotype and morphology.

Apneustic anesthesia ventilation improves pulmonary function in anesthetized bottlenose dolphins (Tursiops truncatus).

Use of mechanical ventilation during general anesthesia is a necessary practice in the anesthetization of small cetaceans as spontaneous ventilation fails to provide adequate gas exchange. Currently available methods of ventilation do not account for the intermittent breathing strategy of representative species within this infraorder of fully aquatic mammals and may have a significant effect on cardiac and respiratory physiology. To understand the impact of mechanical ventilation on cardiopulmonary function in one small species of cetacean, the bottlenose dolphin (Tursiops truncatus), we compared controlled mechanical ventilation (CMV) to a novel ventilation method known as apneustic anesthesia ventilation (AAV). AAV simulates the normal inspiratory breath-hold pattern of dolphins. Ten anesthetic procedures (dental procedure, n = 9; bronchoscopy, n = 2) were performed on nine dolphins (age range: 10-42 years; mean = 32 years; median = 37 years; female = 3, 40%; male = 6, 60%). In a cross-over study design, dolphins were instrumented and randomly assigned to AAV or CMV as the initial mode of ventilation, then switched to the alternate mode. Baseline cardiopulmonary data were collected and again after 30 min on each mode of ventilation. Cardiac index, stroke volume index, systemic vascular resistance, alveolar dead space, alveolar-arterial oxygen tension gradient, arterial oxygen content, oxygen delivery index, and dynamic respiratory system compliance index were calculated at each of the four time points. During AAV, dolphins had higher arterial oxygen tension, higher mean airway pressure, reduced alveolar dead space ventilation and lower alveolar-arterial oxygen difference. Cardiovascular performance was not statistically different between the two modes. Our study suggests AAV, which more closely resembles the conscious intermittent respiratory pattern phenotype of dolphins, improves ventilation and pulmonary function in the anesthetized dolphin. Future studies should evaluate the cardiopulmonary effects of neutral buoyancy and cardiopulmonary sparing drug protocols to reduce the need for hemodynamic support of current protocols.

Early-life nasal microbiota dynamics relate to longitudinal respiratory phenotypes in urban children

Five distinct respiratory phenotypes based on latent classes of longitudinal patterns of wheezing, allergic sensitization. and pulmonary function measured in urban children from ages from 0 to 7 years have previously been described. Our aim was to determine whether distinct respiratory phenotypes are associated with early-life upper respiratory microbiota development and environmental microbial exposures. Microbiota profiling was performed using 16S ribosomal RNA-based sequencing of nasal samples collected at age 12 months (n= 120) or age 36 months (n= 142) and paired house dust samples collected at 3 months (12-month, n= 73; 36-month, n= 90) from all 4 centers in the Urban Environment and Childhood Asthma (URECA) cohort. In these high-risk urban children, nasal microbiota increased in diversity between ages 12 and 36 months (ß= 2.04; P= .006). Age-related changes in microbiota evenness differed significantly by respiratory phenotypes (interaction P= .0007), increasing most in the transient wheeze group. At age 12 months, respiratory illness (R2= 0.055; P= .0001) and dominant bacterial genus (R2= 0.59; P= .0001) explained variance in nasal microbiota composition, and enrichment of Moraxella and Haemophilus members was associated with both transient and high-wheeze respiratory phenotypes. By age 36months, nasal microbiota was significantly associated with respiratory phenotypes (R2= 0.019; P= .0376), and Moraxella-dominated microbiota was associated specifically with atopy-associated phenotypes. Analysis of paired house dust and nasal samples indicated that 12 month olds with low wheeze and atopy incidence exhibited the largest number of shared bacterial taxa with their environment. Nasal microbiota development over the course of early childhood and composition at age 3 years are associated with longitudinal respiratory phenotypes. These data provide evidence supporting an early-life window of airway microbiota development that is influenced by environmental microbial exposures in infancy and associates with wheeze- and atopy-associated respiratory phenotypes through age 7 years.