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117 citation(s) found for "G Iyer, Prasad".

Obesity and GERD impair esophageal epithelial permeability through 2 distinct mechanisms
Blevins, Christopher H. , Dierkhising, Ross , Geno, Debra M., Johnson, Michele L., Vela, Marcelo F. , Iyer, Prasad G. , Katzka, David A. , Blevins, C H , Ravi, Karthik

Neurogastroenterology & Motility | July 31, 2018 | Volume: 30 | Issue: 10 | Pages: No page available

10.1111/nmo.13403 | PMID 30062771 Get It

AbstractBackgroundThe mechanism by which obesity leads to damage independent of reflux is unclear. We aimed to determine the influence of obesity on mean nocturnal baseline impedance (MNBI), a functional measure of the epithelial barrier, in the presence and absence of acid reflux, using ambulatory pH impedance measurements.MethodsTwenty‐four‐hour pH impedance studies performed off medications in Caucasian men with a normal endoscopic examination were assessed for level of acid exposure and MNBI. Four patient groups were studied: Group 1, Not obese and normal acid exposure; Group 2, Obese and normal acid exposure; Group 3, Not obese and increased acid exposure; and Group 4, Obese with increased acid exposure.ResultsOne hundred patients were studied (25 in each group). Mean esophageal mucosal impedance (MI) was substantially lower in obese patients without reflux (Group 2) and non‐obese patients with reflux (Group 3) compared to normal controls (non‐obese, no reflux, Group 1). MI was progressively lower in the distal (vs the proximal) esophagus in GER patients, compared to those without GER. This difference persisted in the presence or absence of obesity. In contrast, in obese patients, the mean MI was significantly lower throughout the esophagus when compared to the non‐obese patients and also persisted in the presence and absence of accompanying reflux. Obesity and reflux were both independently negatively correlated with MI.ConclusionObesity is associated with abnormal esophageal MNBI. In contrast to gastro‐esophageal reflux, this decrease is pan‐esophageal. These data may support a systemic mechanism by which obesity alters the esophageal barrier function.
Barrett Esophagus Length, Nodularity, and Low-grade Dysplasia are Predictive of Progression to Esophageal Adenocarcinoma
Solanky, Dipesh , Krishnamoorthi, Rajesh , Crews, Nicholas R. , Johnson, Michele L., Wolfsen, Herbert C. , Fleischer, David E., Ramirez, Francisco C. , Katzka, David A. , Buttar, Navtej , Iyer, Prasad G. , Crews, Nicholas, Johnson, Michele, Wolfsen, Herbert, Fleischer, David, Katzka, David, Wang, Kenneth

Journal of Clinical Gastroenterology | April 2, 2018 | Volume: 53 | Issue: 5 | Pages: 361-365

10.1097/mcg.0000000000001027 | PMID 29608452 Get It

Goals: To investigate factors predictive of progression from nondysplastic Barrett esophagus (NDBE) or low-grade dysplasia (LGD) to high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) using a large, prospective cohort of patients, wherein all esophageal biopsies undergo expert gastrointestinal pathologist review. Background: Efficacy and cost-effectiveness of endoscopic surveillance to detect incident EAC in the setting of Barrett esophagus (BE), particularly in NDBE patients, is questioned. Previous studies have reported factors predictive of progression to EAC to guide surveillance intervals, but their strength is limited by small sample size and absence of expert gastrointestinal pathologist involvement in esophageal biopsy review. Study: NDBE and LGD subjects were identified from a prospective registry in a tertiary care center. “Progressors” were BE subjects who developed HGD/EAC>12 months after the initial NDBE or LGD diagnosis. Cox proportional hazards model were used to identify predictors of progression. Results: In total, 318 with NDBE and 301 with BE-LGD (mean age, 62.6 y, 85% male) were included. The mean follow-up was 5.3 years. The 7 NDBE and 21 LGD subjects progressed to HGD/EAC. BE length [hazards ratio (HR), 1.16; 95% confidence interval (CI), 1.03-1.29], presence of nodularity (HR, 4.98; 95% CI, 1.80-11.7), and baseline LGD (HR, 2.57; 95% CI, 1.13-6.57) were significant predictors of progression on multivariate analysis. Conclusions: In this well-defined cohort of NDBE and BE-LGD subjects, BE length, presence of LGD, and nodularity were independent predictors of progression to HGD/EAC. These factors may aid in identifying high-risk patients who may benefit from closer endoscopic surveillance/therapy.
Association of sporadic and familial Barrett's esophagus with breast cancer
Chan, Megan , Blum, Andrew E., Chandar, Apoorva K., Emmons, Agnieszka, Shindo, Yuri, Brock, Wendy , Wang, J S, Iyer, Prasad G. , Shaheen, Nicholas J. , Thota, Prashanthi N. , Guda, Kishore , Chak, Amitabh , Falk, Gary W. , Canto, Marcia Irene , Grady, William M. , Abrams, Julian A

Diseases of the Esophagus | March 8, 2018 | Volume: 31 | Issue: 4 | Pages: No page available

10.1093/dote/doy007 | PMID 29528378 Get It

Comparative Assessment of Patient Preferences and Tolerability in Barrett Esophagus Screening
Blevins, Christopher H. , Egginton, Jason S. , Shah, Nilay D., Johnson, Michele L., Iyer, Prasad G.

Journal of Clinical Gastroenterology | January 23, 2018 | Volume: 52 | Issue: 10 | Pages: 880-884

10.1097/mcg.0000000000000991 | PMID 29369237 Get It

Goals: To determine patient preference for the Barrett esophagus (BE) screening techniques. Background: Sedated esophagogastroduodenoscopy (sEGD) and unsedated transnasal endoscopy (uTNE) are both potential techniques for BE screening. However, systematic assessment of patient preference for these 2 techniques is lacking. As part of a comparative effectiveness randomized trial of BE screening modalities, we measured short-term patient preferences for the following approaches: in-clinic uTNE (huTNE), mobile-based uTNE (muTNE), and sEGD using a novel assessment instrument. Study: Consenting community patients without known BE were randomly assigned to receive huTNE, muTNE, or sEGD, followed by a telephone administered preference and tolerability assessment instrument 24 hours after study procedures. Patient preference was measured by the waiting trade-off method. Results: In total, 201 patients completed screening with huTNE (n=71), muTNE (n=71), or sEGD (n=59), and a telephone interview. Patients’ preferences for sEGD and uTNE using the waiting trade-off method were comparable (P=0.51). Although tolerability scores were superior for sEGD (P<0.001) compared with uTNE, scores for uTNE examinations were acceptable. Conclusions: Patient preference is comparable between sEGD and uTNE for diagnostic examinations conducted in an endoscopy suite or in a mobile setting. Given acceptable tolerability, uTNE may be a viable alternative to sEGD for BE screening.
Identifying DNA methylation biomarkers for non-endoscopic detection of Barrett’s esophagus
Moinova, Helen , LaFramboise, Thomas , Lutterbaugh, James, Chandar, Apoorva K., Dumot, John A. , Faulx, Ashley L., Brock, Wendy , Cabrera, Omar De la Cruz , Guda, Kishore , Barnholtz‐Sloan, Jill S. , Iyer, Prasad G. , Wang, Jean S. , Shaheen, Nicholas J. , Thota, Prashanti N., Willis, Joseph , Chak, Amitabh , Markowitz, Sanford D. , Moinova, Helen R , De la Cruz Cabrera, Omar , Willis, Joseph E , Chak, Amitabh , Markowitz, Sanford D , Barnholtz-Sloan, Jill S , Canto, Marcia Irene

Science Translational Medicine | January 17, 2018 | Volume: 10 | Issue: 424 | Pages: No page available

10.1126/scitranslmed.aao5848 | PMID 29343623 Get It

Combining DNA methylation markers with a swallowable device for sampling the distal esophagus effectively detects Barrett’s neoplasias.
Incidence and predictors of osteoporotic fractures in patients with Barrett's oesophagus: a population‐based nested case‐control study
Kumar, Swarup , Schleck, C. D., Johnson, Michele L., Alexander, J.A., Katzka, David A. , Iyer, Prasad G. , Kumar, S , Iyer, P G , Drake, Matthew T. , Alexander, J. A.

Alimentary Pharmacology & Therapeutics | October 5, 2017 | Volume: 46 | Issue: 11-12 | Pages: 1094-1102

10.1111/apt.14345 | PMID 28980336 Get It

SummaryBackgroundProton pump inhibitors (PPI) are inconsistently associated with osteoporotic fractures. Barrett's oesophagus (BO) patients are treated with high PPI doses for prolonged periods, but there are limited data on the incidence of osteoporosis and fractures in this group pf patients.AimTo estimate the incidence of (and risk factors for) low bone mass (osteoporosis and/or osteopenia) related fractures in a population‐based BO cohort.MethodsAll subjects with BO and a diagnosis of osteoporosis and fractures were identified using Rochester Epidemiology Project resources. The incidence rates of all and osteoporotic fractures in these subjects were compared to an age‐ and gender similar population in Olmsted County to determine standardised incidence ratios (SIR). Predictors were assessed using Cox proportional hazards models.ResultsFive hundred and twenty‐one patients were included (median [IQR] age 61 [52, 72] years; 398 [76%] men) of whom 113 (21.7%) had fractures, and 46 (8.8%) had osteoporotic fractures. The incidence of all fractures and osteoporotic fractures was comparable to that of an age‐ and gender‐matched population (SIR 1.09; 95% CI 0.92‐1.29: SIR 1.05; 95% CI 0.85‐1.29). PPI use, dose or duration of use was not associated with osteoporotic fracture risk (HR 0.87; 95% CI 0.12‐6.39). Independent risk factors for osteoporotic fractures included older age, female gender and higher co‐morbidity index.ConclusionsThe incidence of osteoporotic fractures was not increased in BO patients compared to the general population. In addition, PPI use was not associated with increased fracture risk regardless of the duration of therapy or dose.
Comparative quality assessment of esophageal examination with transnasal and sedated endoscopy
Crews, Nicholas R. , Gorospe, Emmanuel C., Johnson, Michele L., Song, Louis–Michel Wong Kee, Katzka, David A. , Wong Kee Song, Louis-Michel, Iyer, Prasad G. , Iyer, Prasad

Endoscopy International Open | May 5, 2017 | Volume: 05 | Issue: 05 | Pages: E340-E344

10.1055/s-0042-122008 | PMID 28484734 Get It

Abstract Background Unsedated transnasal esophagoscopy (TNE) may offer a less expensive, mobile alternative to sedated esophagogastroduodenoscopy (EGD) for evaluations of reflux related complications. Comparisons of imaging quality by these methods are lacking. Methods Two reviewers evaluated videos of TNE and EGD procedures, performed during a community randomized study comparing endoscopic techniques. Subjects were randomized to EGD, TNE in endoscopy suite, or TNE in mobile research unit. Endoscopic quality was assessed using a validated scoring tool. Results In total, 115 videos (58 EGD, 28 endoscopy suite TNE, and 29 mobile TNE) were reviewed. Overall quality scores for TNE and EGD were excellent without a statistically significant difference (P = 0.30). There were no differences in gastroesophageal junction (GEJ) visualization scores, though EGD scored higher in esophageal passage (P < 0.05) and TNE scored higher in esophageal intubation (P < 0.05). There was no significant difference in any quality score between mobile TNE and gastrointestinal suite TNE. Conclusion Esophageal assessment with TNE or EGD was comparable in overall quality and GEJ visualization. TNE quality was not affected by procedure location. TNE is a feasible option for endoscopic assessment of reflux complications.
Acid-suppressive medications and risk of esophageal adenocarcinoma in patients with Barrett’s esophagus: A systematic review and meta-analysis.
Singh, Siddharth , Garg, Sushil Kumar , Iyer, Prasad G. , El‐Serag, Hashem B. , Singh, Preet Paul

Journal of Clinical Oncology | February 24, 2017 | Volume: 32 | Issue: 3_suppl | Pages: 11-11

10.1200/jco.2014.32.3_suppl.11 Get It

11 Background: Acid-suppressive medications, particularly proton pump inhibitors (PPI), may modify risk of esophageal adenocarcinoma (EAC) in patients with Barrett’s esophagus (BE). We performed a systematic review and meta-analysis of studies evaluating the association between PPIs and histamine receptor antagonists (H2RA) and risk of EAC or high-grade dysplasia (BE-HGD) in patients with BE. Methods: Through a systematic search up to June 2013, we identified 7 observational studies (5 cohort studies and 2 case-control studies; 2,813 patients with BE, 317 cases of EAC and/or BE-HGD, 84.4% PPI users) reporting the association between PPIs or H2RA and EAC in patients with BE. Summary odds ratio (OR) with 95% confidence intervals (CI) was estimated using random effects model, and heterogeneity was measured using the inconsistency index (I2). Results: On meta-analysis, PPI use was associated with 71% reduction in EAC risk in patients with BE (adjusted OR, 0.29; 95% CI, 0.12-0.71). There was a trend toward a dose-response relationship with PPI use for >2 years protective against EAC [3 studies; PPI use >2 years vs. <2 years (as compared to no use): OR, 0.45 (0.19-1.06) vs. 1.09 (0.47-2.56)]. Considerable heterogeneity was observed in the overall analysis (I2=81%). On restricting analysis to 5 cohort studies, use of PPIs was consistently associated with a lower risk of EAC and/or BE-HGD (adjusted OR, 0.33; 95% CI, 0.19-0.58; I2=9%). H2RA use was not associated with decreased risk of EAC in patients with BE based on 2 studies (adjusted OR, 1.15; 95% CI, 0.77-1.72). Using a 67% summary risk reduction (derived from cohort studies) of EAC and/or BE-HGD with PPI use in patients with BE, and observed cumulative incidence rates of EAC and/or BE-HGD in patients with BE overall as 10.2 per 1,000 patient years, we estimate the number needed to treat with PPIs to prevent 1 case of EAC or BE-HGD in BE patients at 147. Conclusions: Based on meta-analysis of observational studies, the use of PPI, but not H2RA appears to be associated with a decreased risk of EAC and/or BE-HGD in patients with BE. PPI use should be considered in BE, and chemopreventive trials of PPIs in patients with BE are warranted.
Systematic review with meta‐analysis: prevalent vs. incident oesophageal adenocarcinoma and high‐grade dysplasia in Barrett's oesophagus
Visrodia, Kavel , Singh, Siddharth , Krishnamoorthi, Rajesh , Ahlquist, David A. , Wang, K. K., Iyer, Prasad G. , Katzka, David A.

Alimentary Pharmacology & Therapeutics | August 26, 2016 | Volume: 44 | Issue: 8 | Pages: 775-784

10.1111/apt.13783 | PMID 27562355 Get It

SummaryBackgroundThe proportion of oesophageal adenocarcinoma that is detected concurrently with initial Barrett's oesophagus diagnosis is not well studied.AimTo compare the proportion of prevalent adenocarcinoma vs. incident adenocarcinoma found during surveillance of Barrett's.MethodsWe performed a systematic search of MEDLINE, EMBASE and Web of Science (from their inception to 31 May 2015) for cohort studies in adults with Barrett's (nondysplastic Barrett's ± Barrett's with low‐grade dysplasia) with minimum average follow‐up of 3 years, and providing numbers of prevalent adenocarcinoma detected (concurrently with Barrett's diagnosis and up to 1 year afterwards) vs. incident adenocarcinoma detected (greater than 1 year after Barrett's diagnosis). Pooled weighted proportions of prevalent and incident adenocarcinoma were calculated, using a random effects model.ResultsOn meta‐analysis of 13 studies reporting on 603 adenocarcinomas in 9657 Barrett's patients, 85.1% of adenocarcinomas were classified as prevalent [95% confidence interval (CI), 78.1–90.2%) and 14.9% as incident (95% CI, 9.8–21.9%), with substantial heterogeneity (I2 = 66%). Among nine studies reporting on 787 high‐grade dysplasia and oesophageal adenocarcinomas in 8098 Barrett's patients, the proportion of prevalent high‐grade dysplasia‐oesophageal adenocarcinoma was similar at 80.5% (95% CI, 68.1–88.8%, I2 = 87%). These results remained stable across multiple subgroup analyses including study quality, setting, duration of follow‐up and presence of baseline dysplasia.ConclusionsIn our meta‐analysis, four of five patients diagnosed with adenocarcinoma or high‐grade dysplasia at index endoscopy or within 1 year of Barrett's follow‐up were considered to be prevalent cases. Continued efforts are needed to identify patients with Barrett's before the development of adenocarcinoma.
RNA Sequencing Identifies Transcriptionally Viable Gene Fusions in Esophageal Adenocarcinomas
Blum, Andrew E., Venkitachalam, Srividya , Kieber-Emmons, Ann Marie, Ravi, Lakshmeswari, Chandar, Apoorva K., Iyer, Prasad G. , Wang, Jean S. , Shaheen, Nicholas J. , Barnholtz‐Sloan, Jill S. , Markowitz, Sanford D. , Willis, Joseph , Shyr, Yu , Chak, Amitabh , Varadan, Vinay , Guda, Kishore , Guo, Yan Ping , Canto, Marcia Irene , Willis, Joseph E , Barnholtz-Sloan, Jill S

Cancer Research | August 8, 2016 | Volume: 76 | Issue: 19 | Pages: 5628-5633

10.1158/0008-5472.can-16-0979 | PMID 27503924 Get It

Abstract Esophageal adenocarcinoma is a deadly cancer with increasing incidence in the United States, but mechanisms underlying pathogenesis are still mostly elusive. In addressing this question, we assessed gene fusion landscapes by comprehensive RNA sequencing (RNAseq) of 55 pretreatment esophageal adenocarcinoma and 49 nonmalignant biopsy tissues from patients undergoing endoscopy for Barrett's esophagus. In this cohort, we identified 21 novel candidate esophageal adenocarcinoma–associated fusions occurring in 3.33% to 11.67% of esophageal adenocarcinomas. Two candidate fusions were selected for validation by PCR and Sanger sequencing in an independent set of pretreatment esophageal adenocarcinoma (N = 115) and nonmalignant (N = 183) biopsy tissues. In particular, we observed RPS6KB1–VMP1 gene fusion as a recurrent event occurring in approximately 10% of esophageal adenocarcinoma cases. Notably, esophageal adenocarcinoma cases harboring RPS6KB1–VMP1 fusions exhibited significantly poorer overall survival as compared with fusion-negative cases. Mechanistic investigations established that the RPS6KB1–VMP1 transcript coded for a fusion protein, which significantly enhanced the growth rate of nondysplastic Barrett's esophagus cells. Compared with the wild-type VMP1 protein, which mediates normal cellular autophagy, RPS6KB1–VMP1 fusion exhibited aberrant subcellular localization and was relatively ineffective in triggering autophagy. Overall, our findings identified RPS6KB1–VMP1 as a genetic fusion that promotes esophageal adenocarcinoma by modulating autophagy-related processes, offering new insights into the molecular pathogenesis of esophageal adenocarcinomas. Cancer Res; 76(19); 5628–33. ©2016 AACR.