Browsing by Author "Arora, Amit"

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    Genetic Admixture and Survival in Diverse Populations with Pulmonary Arterial Hypertension
    (American Thoracic Society, 2020-06-01) Karnes, Jason H.; Wiener, Howard W.; Schwantes-An, Tae-Hwi; Natarajan, Balaji; Sweatt, Andrew J.; Chaturvedi, Abhishek; Arora, Amit; Batai, Ken; Nair, Vineet; Steiner, Heidi E.; Giles, Jason B.; Yu, Jeffrey; Hosseini, Maryam; Pauciulo, Michael W.; Lutz, Katie A.; Coleman, Anna W.; Feldman, Jeremy; Vanderpool, Rebecca; Tang, Haiyang; Garcia, Joe G.N.; Yuan, Jason X.J; Kittles, Rick; de Jesus Perez, Vinicio; Zamanian, Roham T.; Rischard, Franz; Tiwari, Hemant K.; Nichols, William C.; Benza, Raymond L.; Desai, Ankit A.; Medicine, School of Medicine
    Rationale: Limited information is available on racial/ethnic differences in pulmonary arterial hypertension (PAH).Objectives: Determine effects of race/ethnicity and ancestry on mortality and disease outcomes in diverse patients with PAH.Methods: Patients with Group 1 PAH were included from two national registries with genome-wide data and two local cohorts, and further incorporated in a global meta-analysis. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for transplant-free, all-cause mortality in Hispanic patients with non-Hispanic white (NHW) patients as the reference group. Odds ratios (ORs) for inpatient-specific mortality in patients with PAH were also calculated for race/ethnic groups from an additional National Inpatient Sample dataset not included in the meta-analysis.Measurements and Main Results: After covariate adjustment, self-reported Hispanic patients (n = 290) exhibited significantly reduced mortality versus NHW patients (n = 1,970) after global meta-analysis (HR, 0.60 [95% CI, 0.41-0.87]; P = 0.008). Although not significant, increasing Native American genetic ancestry appeared to account for part of the observed mortality benefit (HR, 0.48 [95% CI, 0.23-1.01]; P = 0.053) in the two national registries. Finally, in the National Inpatient Sample, an inpatient mortality benefit was also observed for Hispanic patients (n = 1,524) versus NHW patients (n = 8,829; OR, 0.65 [95% CI, 0.50-0.84]; P = 0.001). An inpatient mortality benefit was observed for Native American patients (n = 185; OR, 0.38 [95% CI, 0.15-0.93]; P = 0.034).Conclusions: This study demonstrates a reproducible survival benefit for Hispanic patients with Group 1 PAH in multiple clinical settings. Our results implicate contributions of genetic ancestry to differential survival in PAH.
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    Genetic loci associated with skin pigmentation in African Americans and their effects on vitamin D deficiency
    (Public Library of Science, 2021-02-18) Batai, Ken; Cui, Zuxi; Arora, Amit; Shah-Williams, Ebony; Hernandez, Wenndy; Ruden, Maria; Hollowell, Courtney M. P.; Hooker, Stanley E.; Bathina, Madhavi; Murphy, Adam B.; Bonilla, Carolina; Kittles, Rick A.; Medical and Molecular Genetics, School of Medicine
    A recent genome-wide association study (GWAS) in African descent populations identified novel loci associated with skin pigmentation. However, how genomic variations affect skin pigmentation and how these skin pigmentation gene variants affect serum 25(OH) vitamin D variation has not been explored in African Americans (AAs). In order to further understand genetic factors that affect human skin pigmentation and serum 25(OH)D variation, we performed a GWAS for skin pigmentation with 395 AAs and a replication study with 681 AAs. Then, we tested if the identified variants are associated with serum 25(OH) D concentrations in a subset of AAs (n = 591). Skin pigmentation, Melanin Index (M-Index), was measured using a narrow-band reflectometer. Multiple regression analysis was performed to identify variants associated with M-Index and to assess their role in serum 25(OH)D variation adjusting for population stratification and relevant confounding variables. A variant near the SLC24A5 gene (rs2675345) showed the strongest signal of association with M-Index (P = 4.0 x 10-30 in the pooled dataset). Variants in SLC24A5, SLC45A2 and OCA2 together account for a large proportion of skin pigmentation variance (11%). The effects of these variants on M-Index was modified by sex (P for interaction = 0.009). However, West African Ancestry (WAA) also accounts for a large proportion of M-Index variance (23%). M-Index also varies among AAs with high WAA and high Genetic Score calculated from top variants associated with M-Index, suggesting that other unknown genomic factors related to WAA are likely contributing to skin pigmentation variation. M-Index was not associated with serum 25(OH)D concentrations, but the Genetic Score was significantly associated with vitamin D deficiency (serum 25(OH)D levels less than 12 ng/mL) (OR, 1.30; 95% CI, 1.04-1.64). The findings support the hypothesis suggesting that skin pigmentation evolved responding to increased demand for subcutaneous vitamin D synthesis in high latitude environments.
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    Mendelian randomisation and experimental medicine approaches to interleukin-6 as a drug target in pulmonary arterial hypertension
    (European Respiratory Society, 2022-03-10) Toshner, Mark; Church, Colin; Harbaum, Lars; Rhodes, Christopher; Villar Moreschi, Sofia S.; Liley, James; Jones, Rowena; Arora, Amit; Batai, Ken; Desai, Ankit A.; Coghlan, John G.; Gibbs, J. Simon R.; Gor, Dee; Gräf, Stefan; Harlow, Louise; Hernandez-Sanchez, Jules; Howard, Luke S.; Humbert, Marc; Karnes, Jason; Kiely, David G.; Kittles, Rick; Knightbridge, Emily; Lam, Brian; Lutz, Katie A.; Nichols, William C.; Pauciulo, Michael W.; Pepke-Zaba, Joanna; Suntharalingam, Jay; Soubrier, Florent; Trembath, Richard C.; Schwantes-An, Tae-Hwi L.; Wort, S. John; Wilkins, Martin R.; Gaine, Sean; Morrell, Nicholas W.; Corris, Paul A.; Uniphy Clinical Trials Network; Medicine, School of Medicine
    Background: Inflammation and dysregulated immunity are important in the development of pulmonary arterial hypertension (PAH). Compelling preclinical data supports the therapeutic blockade of interleukin-6 (IL-6) signalling. Methods: We conducted a phase 2 open-label study of intravenous tocilizumab (8 mg·kg-1) over 6 months in patients with group 1 PAH. Co-primary end-points were safety, defined by incidence and severity of adverse events, and change in pulmonary vascular resistance. Separately, a mendelian randomisation study was undertaken on 11 744 individuals with European ancestry including 2085 patients with idiopathic/heritable disease for the IL-6 receptor (IL6R) variant (rs7529229), known to associate with circulating IL-6R levels. Results: We recruited 29 patients (male/female 10/19; mean±sd age 54.9±11.4 years). Of these, 19 had heritable/idiopathic PAH and 10 had connective tissue disease-associated PAH. Six were withdrawn prior to drug administration; 23 patients received at least one dose of tocilizumab. Tocilizumab was discontinued in four patients owing to serious adverse events. There were no deaths. Despite evidence of target engagement in plasma IL-6 and C-reactive protein levels, both intention-to-treat and modified intention-to-treat analyses demonstrated no change in pulmonary vascular resistance. Inflammatory markers did not predict treatment response. Mendelian randomisation did not support an effect of the lead IL6R variant on risk of PAH (OR 0.99, p=0.88). Conclusion: Adverse events were consistent with the known safety profile of tocilizumab. Tocilizumab did not show any consistent treatment effect.