Racial and ethnic associations with interstitial lung disease and healthcare utilization in patients with systemic sclerosis.

Rationale: Racial and ethnic differences in presentation and outcomes have been reported in systemic sclerosis (SSc) and SSc-interstitial lung disease (ILD). However, diverse cohorts and additional modeling can improve understanding of risk features and outcomes, which is important for reducing associated disparities. Objectives: To determine if there are racial/ethnic differences associated with SSc-ILD risk and age; time intervals between SSc and ILD, and with emergency department (ED) visit or hospitalization rates. Methods: A retrospective cohort study using electronic health record data from an integrated health system, over a 5.5 year period was conducted using clinical and sociodemographic variables, models were generated with sequential adjustments for these variables. Logistic regression models were used to examine the association of covariates with ILD and age at SSc-ILD. Healthcare outcomes were analyzed with complementary log-log regression models. Results: The cohort included 756 adults (83.6% female, 80.3% non-Hispanic White) with SSc with a mean age of 59 years. Overall, 33.7% of patients in the cohort had an ILD code, with increased odds for Asian (odds ratio [OR], 2.59; 95% confidence interval [CI], 1.29, 5.18; P =.007) compared to White patients. The age in years of patients with SSc-ILD was younger for Hispanic (mean difference, -6.5; 95% CI, -13, -0.21; P = 0.04) and Black/African American patients (-10; 95% CI -16, -4.9; P <0.001) compared to White patients. Black/African American patients were more likely to have an ILD code before an SSc code (59% compared to 20.6% of White patients), and had the shortest interval from SSc to ILD (3 months). Black/African American (HR, 2.59; 95% CI 1.47, 4.49; P =0.001) and Hispanic patients (HR 2.29; 95% CI 1.37, 3.82; P =0.002) had higher rates of an ED visit. Conclusion: In this study, SSc-ILD presentation and outcomes differed by racial/ethnic group (increased odds of SSc-ILD, younger age at SSc-ILD, and preceding diagnosis with respect to SSc, rates of ED visit), some of which was attenuated with adjustment for clinical and sociodemographic characteristics. Differing presentation may be driven by social drivers of health (SDOH), autoantibody profiles, or other key unmeasured factors contributing to susceptibility and severity.

Bronchial epithelial gene expression and interstitial lung abnormalities.

INTRODUCTION: Interstitial lung abnormalities (ILA) often represent early fibrotic changes that can portend a progressive fibrotic phenotype. In particular, the fibrotic subtype of ILA is associated with increased mortality and rapid decline in lung function. Understanding the differential gene expression that occurs in the lungs of participants with fibrotic ILA may provide insight into development of a useful biomarker for early detection and therapeutic targets for progressive pulmonary fibrosis. METHODS: Measures of ILA and gene expression data were available in 213 participants in the Detection of Early Lung Cancer Among Military Personnel (DECAMP1 and DECAMP2) cohorts. ILA was defined using Fleischner Society guidelines and determined by sequential reading of computed tomography (CT) scans. Primary analysis focused on comparing gene expression in ILA with usual interstitial pneumonia (UIP) pattern with those with no ILA. RESULTS: ILA was present in 51 (24%) participants, of which 16 (7%) were subtyped as ILA with a UIP pattern. One gene, pro platelet basic protein (PPBP) and seventeen pathways (e.g. TNF-α signalling) were significantly differentially expressed between those with a probable or definite UIP pattern of ILA compared to those without ILA. 16 of these 17 pathways, but no individual gene, met significance when comparing those with ILA to those without ILA. CONCLUSION: Our study demonstrates that abnormal inflammatory processes are apparent in the bronchial airway gene expression profiles of smokers with and without lung cancer with ILA. Future studies with larger and more diverse populations will be needed to confirm these findings.

Development and validation of algorithms to build an electronic health record based cohort of patients with systemic sclerosis.

OBJECTIVES: To evaluate methods of identifying patients with systemic sclerosis (SSc) using International Classification of Diseases, Tenth Revision (ICD-10) codes (M34*), electronic health record (EHR) databases and organ involvement keywords, that result in a validated cohort comprised of true cases with high disease burden. METHODS: We retrospectively studied patients in a healthcare system likely to have SSc. Using structured EHR data from January 2016 to June 2021, we identified 955 adult patients with M34* documented 2 or more times during the study period. A random subset of 100 patients was selected to validate the ICD-10 code for its positive predictive value (PPV). The dataset was then divided into a training and validation sets for unstructured text processing (UTP) search algorithms, two of which were created using keywords for Raynaud's syndrome, and esophageal involvement/symptoms. RESULTS: Among 955 patients, the average age was 60. Most patients (84%) were female; 75% of patients were White, and 5.2% were Black. There were approximately 175 patients per year with the code newly documented, overall 24% had an ICD-10 code for esophageal disease, and 13.4% for pulmonary hypertension. The baseline PPV was 78%, which improved to 84% with UTP, identifying 788 patients likely to have SSc. After the ICD-10 code was placed, 63% of patients had a rheumatology office visit. Patients identified by the UTP search algorithm were more likely to have increased healthcare utilization (ICD-10 codes 4 or more times 84.1% vs 61.7%, p < .001), organ involvement (pulmonary hypertension 12.7% vs 6% p = .011) and medication use (mycophenolate use 28.7% vs 11.4%, p < .001) than those identified by the ICD codes alone. CONCLUSION: EHRs can be used to identify patients with SSc. Using unstructured text processing keyword searches for SSc clinical manifestations improved the PPV of ICD-10 codes alone and identified a group of patients most likely to have SSc and increased healthcare needs.

Suspected Interstitial Lung Disease in COPDGene Study.

Rationale: Although interstitial lung abnormalities (ILA), specific patterns of incidentally-detected abnormal density on computed tomography, have been associated with abnormal lung function and increased mortality, it is unclear if a subset with incidental interstitial lung disease (ILD) accounts for these adverse consequences. Objectives: To define the prevalence and risk factors of suspected ILD and assess outcomes. Methods: Suspected ILD was evaluated in the COPDGene (Chronic Obstructive Pulmonary Disease Genetic Epidemiology) study, defined as ILA and at least one additional criterion: definite fibrosis on computed tomography, FVC less than 80% predicted, or DLCO less than 70% predicted. Multivariable linear, longitudinal, and Cox proportional hazards regression models were used to assess associations with St. George's Respiratory Questionnaire, 6-minute-walk test, supplemental oxygen use, respiratory exacerbations, and mortality. Measurements and Main Results: Of 4,361 participants with available data, 239 (5%) had evidence for suspected ILD, whereas 204 (5%) had ILA without suspected ILD. In multivariable analyses, suspected ILD was associated with increased St. George's Respiratory Questionnaire score (mean difference [MD], 3.9 points; 95% confidence interval [CI], 0.6-7.1; P = 0.02), reduced 6-minute-walk test (MD, -35 m; 95% CI, -56 m to -13 m; P = 0.002), greater supplemental oxygen use (odds ratio [OR], 2.3; 95% CI, 1.1-5.1; P = 0.03) and severe respiratory exacerbations (OR, 2.9; 95% CI, 1.1-7.5; P = 0.03), and higher mortality (hazard ratio, 2.4; 95% CI, 1.2-4.6; P = 0.01) compared with ILA without suspected ILD. Risk factors associated with suspected ILD included self-identified Black race (OR, 2.0; 95% CI, 1.1-3.3; P = 0.01) and pack-years smoking history (OR, 1.2; 95% CI, 1.1-1.3; P = 0.0005). Conclusions: Suspected ILD is present in half of those with ILA in COPDGene and is associated with exercise decrements and increased symptoms, supplemental oxygen use, severe respiratory exacerbations, and mortality.

Interdependence of hypoxia and ß-adrenergic receptor signaling in pulmonary arterial hypertension.

The ß-adrenergic receptor (ßAR) exists in an equilibrium of inactive and active conformational states, which shifts in response to different ligands and results in downstream signaling. In addition to cAMP, ßAR signals to hypoxia-inducible factor 1 (HIF-1). We hypothesized that a ßAR-active conformation (R**) that leads to HIF-1 is separable from the cAMP-activating conformation (R*) and that pulmonary arterial hypertension (PAH) patients with HIF-biased conformations would not respond to a cAMP agonist. We compared two cAMP agonists, isoproterenol and salbutamol, in vitro. Isoproterenol increased cAMP and HIF-1 activity, while salbutamol increased cAMP and reduced HIF-1. Hypoxia blunted agonist-stimulated cAMP, consistent with receptor equilibrium shifting toward HIF-activating conformations. Similarly, isoproterenol increased HIF-1 and erythropoiesis in mice, while salbutamol decreased erythropoiesis. ßAR overexpression in cells increased glycolysis, which was blunted by HIF-1 inhibitors, suggesting increased ßAR leads to increased hypoxia-metabolic effects. Because PAH is also characterized by HIF-related glycolytic shift, we dichotomized PAH patients in the Pulmonary Arterial Hypertension Treatment with Carvedilol for Heart Failure trial (NCT01586156) based on right ventricular (RV) glucose uptake to evaluate ßAR ligands. Patients with high glucose uptake had more severe disease than those with low uptake. cAMP increased in response to isoproterenol in mononuclear cells from low-uptake patients but not in high-uptake patients' cells. When patients were treated with carvedilol for 1 wk, the low-uptake group decreased RV systolic pressures and pulmonary vascular resistance, but high-uptake patients had no physiologic responses. The findings expand the paradigm of ßAR activation and uncover a novel PAH subtype that might benefit from ß-blockers.

Relative quantification of beta-adrenergic receptor in peripheral blood cells using flow cytometry.

Beta-adrenergic receptors (ß-ARs) play a critical role in many diseases. Quantification of ß-AR density may have clinical implications in terms of assessing disease severity and identifying patients who could potentially benefit from beta-blocker therapy. Classical methods for ß-AR quantification are based on labor-intensive and time-consuming radioligand binding assays. Here, we report optimization of a flow cytometry-based method utilizing a biotinylated ß-AR ligand alprenolol as a probe and use of this method to quantify relative receptor expression in healthy controls (HC). Quantum™ MESF beads were used for quantification in absolute fluorescence units. The probe was chemically modified by adding a spacer moiety between biotin and alprenolol to stabilize receptor binding, thus preventing binding decay. Testing of three different standard cell fixation and permeabilization methods (formaldehyde fixation and saponin, Tween-20, or Triton-X 100 permeabilization) showed that the formaldehyde/Triton-X 100 method yielded the best results. ß-AR expression was significantly higher in granulocytes compared to mononuclear cells. These data show that flow cytometric quantification of relative ß-AR expression in circulating leukocytes is a suitable technology for large-scale clinical application. © 2018 International Society for Advancement of Cytometry.

Flow Cytometric Quantification of Peripheral Blood Cell ß-Adrenergic Receptor Density and Urinary Endothelial Cell-Derived Microparticles in Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is a heterogeneous disease characterized by severe angiogenic remodeling of the pulmonary artery wall and right ventricular hypertrophy. Thus, there is an increasing need for novel biomarkers to dissect disease heterogeneity, and predict treatment response. Although ß-adrenergic receptor (ßAR) dysfunction is well documented in left heart disease while endothelial cell-derived microparticles (Ec-MPs) are established biomarkers of angiogenic remodeling, methods for easy large clinical cohort analysis of these biomarkers are currently absent. Here we describe flow cytometric methods for quantification of ßAR density on circulating white blood cells (WBC) and Ec-MPs in urine samples that can be used as potential biomarkers of right heart failure in PAH. Biotinylated ß-blocker alprenolol was synthesized and validated as a ßAR specific probe that was combined with immunophenotyping to quantify ßAR density in circulating WBC subsets. Ec-MPs obtained from urine samples were stained for annexin-V and CD144, and analyzed by a micro flow cytometer. Flow cytometric detection of alprenolol showed that ßAR density was decreased in most WBC subsets in PAH samples compared to healthy controls. Ec-MPs in urine was increased in PAH compared to controls. Furthermore, there was a direct correlation between Ec-MPs and Tricuspid annular plane systolic excursion (TAPSE) in PAH patients. Therefore, flow cytometric quantification of peripheral blood cell ßAR density and urinary Ec-MPs may be useful as potential biomarkers of right ventricular function in PAH.

Effect of Age on Phenotype and Outcomes in Pulmonary Arterial Hypertension Trials.

BACKGROUND: In recent years, the population of patients with pulmonary arterial hypertension (PAH) has changed dramatically, including more advanced age at diagnosis. We hypothesized that older patients have a distinct clinical profile with different disease characteristics and response to intervention. METHODS: All previously published treatment studies for PAH conducted by United Therapeutics including seven randomized, placebo-controlled trials and one extension study were included and analyzed to assess the association of age with various demographic, functional, hemodynamic, and outcome variables. RESULTS: A total of 2,627 patients across three age groups were included: ≤ 50 (n = 1,438, 54.7%), 51 to 64 (n = 780, 29.7%), and ≥ 65 years (n = 409, 15.6%). In comparison with the youngest group, the oldest age group had higher proportions of connective tissue disease-associated etiology (range across the studies, 27%-49% vs 13%-21%), higher proportions of New York Heart Association Functional classes III and IV (74%-91% vs 57%-84%), shorter baseline 6-min walk distance (6MWD) (261-316 vs 335-371 m), better hemodynamic measurements including lower baseline mean pulmonary artery pressure (48-51 vs 58-63 mmHg), and smaller changes in 6MWD from baseline to endpoint (-5.6 to 24 vs 14-43 m). Age remained associated with change in 6MWD when adjusting for covariates in multivariate analyses. CONCLUSIONS: For the first time, using data from large randomized controlled trials, this study characterizes the different phenotype and outcomes of older patients with PAH, which includes different disease etiology, diminished functional status, and decreased response to intervention. This may have significant implications for the management of this patient population and design of future therapy trials.

Novel broad-spectrum inhibitors of bacterial methionine aminopeptidase.

With increasing emergence of multi-drug resistant infections, there is a dire need for new classes of compounds that act through unique mechanisms. In this work, we describe the discovery and optimization of a novel series of inhibitors of bacterial methionine aminopeptidase (MAP). Through a high-throughput screening campaign, one azepinone amide hit was found that resembled the native peptide substrate and possessed moderate biochemical potency against three bacterial isozymes. X-ray crystallography was used in combination with substrate-based design to direct the rational optimization of analogs with sub-micromolar potency. The novel compounds presented here represent potent broad-spectrum biochemical inhibitors of bacterial MAP and have the potential to lead to the development of new medicines to combat serious multi-drug resistant infections.

Biology and flow cytometry of proangiogenic hematopoietic progenitors cells.

During development, hematopoiesis and neovascularization are closely linked to each other via a common bipotent stem cell called the hemangioblast that gives rise to both hematopoietic cells and endothelial cells. In postnatal life, this functional connection between the vasculature and hematopoiesis is maintained by a subset of hematopoietic progenitor cells endowed with the capacity to differentiate into potent proangiogenic cells. These proangiogenic hematopoietic progenitors comprise a specific subset of bone marrow (BM)-derived cells that homes to sites of neovascularization and possess potent paracrine angiogenic activity. There is emerging evidence that this subpopulation of hematopoietic progenitors plays a critical role in vascular health and disease. Their angiogenic activity is distinct from putative "endothelial progenitor cells" that become structural cells of the endothelium by differentiation into endothelial cells. Proangiogenic hematopoietic progenitor cell research requires multidisciplinary expertise in flow cytometry, hematology, and vascular biology. This review provides a comprehensive overview of proangiogenic hematopoietic progenitor cell biology and flow cytometric methods to detect these cells in the peripheral blood circulation and BM.

Novel rapidly diversifiable antimicrobial RNA polymerase switch region inhibitors with confirmed mode of action in Haemophilus influenzae.

A series of inhibitors with a squaramide core was synthesized following its discovery in a high-throughput screen for novel inhibitors of a transcription-coupled translation assay using Escherichia coli S30 extracts. The inhibitors were inactive when the plasmid substrate was replaced with mRNA, suggesting they interfered with transcription. This was confirmed by their inhibition of purified E. coli RNA polymerase. The series had antimicrobial activity against efflux-negative strains of E. coli and Haemophilus influenzae. Like rifampin, the squaramides preferentially inhibited synthesis of RNA and protein over fatty acids, peptidoglycan, and DNA. However, squaramide-resistant mutants were not cross-resistant to rifampin. Nine different mutations were found in parts of rpoB or rpoC that together encode the so-called switch region of RNA polymerase. This is the binding site of the natural antibiotics myxopyronin, corallopyronin, and ripostatin and the drug fidaxomicin. Computational modeling using the X-ray crystal structure of the myxopyronin-bound RNA polymerase of Thermus thermophilus suggests a binding mode of these inhibitors that is consistent with the resistance mutations. The squaramides are the first reported non-natural-product-related, rapidly diversifiable antibacterial inhibitors acting via the switch region of RNA polymerase.

Discovery of a novel azaindole class of antibacterial agents targeting the ATPase domains of DNA gyrase and Topoisomerase IV.

We present the discovery and optimization of a novel series of bacterial topoisomerase inhibitors. Starting from a virtual screening hit, activity was optimized through a combination of structure-based design and physical property optimization. Synthesis of fewer than a dozen compounds was required to achieve inhibition of the growth of methicillin-resistant Staphyloccus aureus (MRSA) at compound concentrations of 1.56 µM. These compounds simultaneously inhibit DNA gyrase and Topoisomerase IV at similar nanomolar concentrations, reducing the likelihood of the spontaneous occurrence of target-based mutations resulting in antibiotic resistance, an increasing threat in the treatment of serious infections.