Learn about the transformative and innovative research by our faculty.


Gastrointestinal Bleeding at CT Angiography and CT Enterography: Imaging Atlas and Glossary of Terms

Guglielmo FF, Wells ML, Bruining DH, Strate LL, Huete Á, Gupta A, Soto JA, Allen BC, Anderson MA, Brook OR, Gee MS, Grand DJ, Gunn ML, Khandelwal A, Park SH, Ramalingam V, Sokhandon F, Yoo DC, Fidler JL.

The purpose of this pictorial review by the Society of Abdominal Radiology GI Bleeding Disease-Focused Panel is to provide a practical resource for radiologists interpreting GI bleeding CT studies that reviews the proper GI bleeding terminology, the most common causes of GI bleeding, key patient history and risk factors, the optimal CT imaging technique, and guidelines for case interpretation and illustrates many common causes of GI bleeding. A CT reporting template is included to help generate radiology reports that can add value to patient care.

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Pcsk9 Deletion Promotes Murine Nonalcoholic Steatohepatitis and Hepatic Carcinogenesis: Role of Cholesterol

Ioannou GN, Lee SP, Linsley PS, Gersuk V, Yeh MM, Chen YY, Peng YJ, Dutta M, Mascarinas G, Molla B, Cui JY, Savard C

Proprotein convertase subtilisin/kexin type 9 (Pcsk9) binds to hepatic low-density lipoprotein receptor (LDLR) and induces its internalization and degradation. Pcsk9 inhibition increases LDLR expression by hepatocytes, which causes increased uptake of circulating LDL, thereby reducing plasma LDL-cholesterol. However, by increasing the uptake of LDL by the liver, Pcsk9 inhibition increases the exposure of the liver to cholesterol, which may result in higher risk of steatohepatitis and ever carcinogenesis.

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Statins and risk of diverticular disease: Nested case–control study

Skajaa N, Schønfeldt Troelsen F, Pedersen L, Ekholm O, Strate LL, Erichsen R, Sørensen HT

Aims: To examine the effect of statin on the subsequent risk of diverticular disease. Methods: We conducted a nested case-control study in Denmark among respondents (>18 years) of the 2010 or the 2013 Danish National Health Survey. Among these, we identified 8809 cases of hospital-diagnosed diverticular disease and risk-set sampled population controls without diverticular disease. Using complete prescription and hospital records, we used conditional logistic regression to compute odds ratios (ORs) associating statin use with diverticular disease. In adjusted analyses, we controlled for hospital-based diagnoses, medication use other than statins, and lifestyle and socioeconomic factors.

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Updates on Age to Start and Stop Colorectal Cancer Screening: Recommendations From the U.S. Multi-Society Task Force on Colorectal Cancer

Patel SG, May FP, Anderson JC, Burke CA, Dominitz JA, Gross SA, Jacobson BC, Shaukat A, Robertson DJ

This document is a focused update to the 2017 colorectal cancer (CRC) screening recommendations from the U.S. Multi-Society Task Force on Colorectal Cancer, which represents the American College of Gastroenterology, the American Gastroenterological Association, and the American Society for Gastrointestinal Endoscopy. This update is restricted to addressing the age to start and stop CRC screening in average-risk individuals and the recommended screening modalities. Although there is no literature demonstrating that CRC screening in individuals under age 50 improves health outcomes such as CRC incidence or CRC-related mortality, sufficient data support the U.S. Multi-Society Task Force to suggest average-risk CRC screening begin at age 45. 

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Marker-based assays for studying gut transit in gnotobiotic and conventional mouse models

Koester ST, Li N, Lachance DM, Dey N

Gastrointestinal motility is regulated by a variety of environmental factors including gut microbes and metabolites. The ability to interrogate mouse models of gut motility has enabled elucidation of these relationships. Here we describe integration of the red carmine dye and fluorescence isothiocyanate-dextran marker-based assays for characterizing gut transit with spatial resolution, along with an optional intracolonic infusion protocol for studying the effects of metabolites on colonic transit. These protocols can be adapted for use in gnotobiotic and conventional mouse models. For complete details on the use and execution of this protocol, please refer to Li et al. (2021).

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Quality measures in HCC care by the Practice Metrics Committee of the American Association for the Study of Liver Diseases. 

Asrani SK, Ghabril MS, Kuo A, Merriman RB, Morgan T, Parikh ND, Ovchinsky N, Kanwal F, Volk ML, Ho C, Serper M, Mehta S, Agopian V, Cabrera R, Chernyak V, El-Serag HB, Heimbach J, Ioannou GN, Kaplan D, Marrero J, Mehta N, Singal A, Salem R, Taddei T, Walling A, Tapper EB.

The burden of hepatocellular carcinoma (HCC) is substantial. To address gaps in HCC care, the American Association for the Study of Liver Diseases (AASLD) Practice Metrics Committee (PMC) aimed to develop a standard set of process-based measures and patient-reported outcomes along the HCC care continuum.

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Selection of patients for large mailed fecal immunochemical test colorectal cancer screening outreach programs: A systematic review

Wang A, Lee B, Patel S, Whitaker E, Issaka RB, Somsouk M

Digital health care offers an opportunity to scale and personalize cancer screening programs, such as mailed outreach for colorectal cancer (CRC) screening. However, studies that describe the patient selection strategy and process for CRC screening are limited. Our objective was to evaluate implementation strategies for selecting patients for CRC screening programs in large health care systems.

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Advancing diversity: the role of international medical graduates

David YN, Issaka RB

A physician workforce that reflects the population it serves has been highlighted as one solution for persistent race-based health disparities. Efforts to diversify the gastroenterology and hepatology workforce in the USA have, historically, focused on improving diversity among fellows and faculty and increasing the number of potential trainees at the medical school and residency levels. Non-US international medical graduates (IMGs) help to diversify the US gastroenterology and hepatology workforce, but several issues need to be addressed so that the effect of IMGs on diversity is sustained.

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A new perspective on NAFLD: focusing on lipid droplets

Eleonora Scorletti, Rotonya M. Carr

Though recent research has improved our understanding of the mechanisms linking LDs accumulation to NAFLD progression, numerous aspects of LD biology are either poorly understood or unknown. In this review, we provide a description of several key mechanisms that contribute to LDs accumulation in the hepatocytes, favouring NAFLD progression.

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Temporal Trends and Evolving Outcomes After Simultaneous Liver-Kidney Transplantation: Results from the US SLKT Consortium

Cullaro G, Sharma P, Jo J, Rassiwala J, VanWagner LB, Wong R, Lai JC, Magee J, Schluger A, Barman P, Patel YA, Walter K, Biggins SW, Verna EC

We aimed to understand the contemporary changes in the characteristics and the determinants of outcomes among simultaneous liver-kidney transplantation (SLKT) recipients at 6 liver transplantation centers in the United States. We retrospectively enrolled SLKT recipients between 2002 and 2017 in the US Multicenter SLKT Consortium. We analyzed time-related trends in recipient characteristics and outcomes with linear regression and nonparametric methods. 

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Risk Factors for Testing Positive for Severe Acute Respiratory Syndrome Coronavirus 2 in a National United States Healthcare System

Fan VS, Dominitz JA, Eastment MC, Locke ER, Green P, Berry K, O'Hare AM, Shah JA, Crothers K, Ioannou GN

Identifying risk factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection could help health systems improve testing and screening strategies. The aim of this study was to identify demographic factors, comorbid conditions, and symptoms independently associated with testing positive for SARS-CoV-2.

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Impact of exposure to patients with COVID-19 on residents and fellows: an international survey of 1420 trainees

Cravero AL, Kim NJ, Feld LD, Berry K, Rabiee A, Bazarbashi N, Bassin S, Lee TH, Moon AM, Qi X, Liang PS, Aby ES, Khan MQ, Young KJ, Patel A, Wijarnpreecha K, Kobeissy A, Hashim A, Houser A, Ioannou GN.

Objectives: To determine how self-reported level of exposure to patients with novel coronavirus 2019 (COVID-19) affected the perceived safety, training and well-being of residents and fellows. Methods: We administered an anonymous, voluntary, web-based survey to a convenience sample of trainees worldwide. The survey was distributed by email and social media posts from April 20th to May 11th, 2020. Respondents were asked to estimate the number of patients with COVID-19 they cared for in March and April 2020.

Imperiale TF, Daggy JK, Imler TD, Sherer EA, Kahi CJ, Larson J, Cardwell J, Johnson CS, Ahnen DJ, Antaki F, Ashley C, Baffy G, Dominitz JA, Hou J, Korsten MA, Nagar A, Promrat K, Robertson DJ, Saini S, Shergill A, Smalley WE.

We sought to quantify the independent effects of age, sex, and race/ethnicity on risk of colorectal cancer (CRC) and advanced neoplasia (AN) in Veterans. We conducted a retrospective, cross-sectional study of Veterans aged 40 to 80 years who had diagnostic or screening colonoscopy between 2002 and 2009 from 1 of 14 Veterans Affairs Medical Centers.

Barahimi M, Lee S, Clark-Snustad K.

We report the case of a 51-year-old male with Crohn's disease (CD) who developed a reproducible pustular rash after ustekinumab (UST) administration. The patient first presented with a pustular rash on his hands, body, extremities, and scalp starting 5 weeks after his initial weight-based UST induction.

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Changes in the associations of race and rurality with SARS-CoV-2 infection, mortality, and case fatality in the United States from February 2020 to March 2021: A population-based cohort study

George N. Ioannou, Jacqueline M. Ferguson, Ann M. O’Hare, Amy S. B. Bohnert, Lisa I. Backus, Edward J. Boyko, Thomas F. Osborne, Matthew L. Maciejewski, C. Barrett Bowling, Denise M. Hynes, Theodore J. Iwashyna, Melody Saysana, Pamela Green, Kristin Berry

We examined whether key sociodemographic and clinical risk factors for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and mortality changed over time in a population-based cohort study. Methods and findings: In a cohort of 9,127,673 persons enrolled in the United States Veterans Affairs (VA) healthcare system, we evaluated the independent associations of sociodemographic and clinical characteristics with SARS-CoV-2 infection (n = 216,046), SARS-CoV-2–related mortality (n = 10,230), and case fatality at monthly intervals between February 1, 2020 and March 31, 2021.

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Dual-Use Transducer for Ultrasound Imaging and Pulsed Focused Ultrasound Therapy

Maria M Karzova, Petr V Yuldashev, Vera A Khokhlova, Fedor A Nartov, Kyle P Morrison, Tatiana D Khokhlova

The use of nonlinear pFUS without contrast agents was recently shown to be beneficial for localized tissue disruption, but required higher ultrasound pressure levels than a conventional ultrasound imaging probe could produce. In this work, we present the design of a compact dual-use 1-MHz transducer for ultrasound-guided pFUS without contrast agents. Nonlinear pressure fields that could be generated by the probe, under realistic power input, were simulated using the Westervelt equation.

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Validation of genetic classifiers derived from mouse and human tumors to identify molecular subtypes of colorectal cancer

Snow SM, Matkowskyj KA, Maresh M, Clipson L, Vo TN, Johnson KA, Deming DA, Newton MA, Grady WM, Pickhardt PJ, Halberg RB.

In this study, we assessed whether an immunohistochemical approach could be used for molecular subtyping of colorectal cancers. We validated two previously published, independent sets of immunohistochemistry classifiers and modified the published methods to improve the accuracy of the scoring methods. In addition, we evaluated whether protein and genetic signatures identified originally in the mouse were linked to clinical outcomes of patients with CRC. 

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Incidence and Risk Factors of Postoperative Mortality and Morbidity After Elective Versus Emergent Abdominal Surgery in a National Sample of 8193 Patients With Cirrhosis

Johnson KM, Newman KL, Green PK, Berry K, Cornia PB, Wu P, Beste LA, Itani K, Harris AHS, Kamath PS, Ioannou GN

Objective: To describe the incidence and risk factors for mortality and morbidity in patients with cirrhosis undergoing elective or emergent abdominal surgeries.
Background: Postoperative morbidity and mortality are higher in patients with cirrhosis; variation by surgical procedure type and cirrhosis severity remain unclear.
 

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Partial Respiratory Motion Compensation for Abdominal Extracorporeal Boiling Histotripsy Treatments With a Robotic Arm

Gilles P L Thomas, Tatiana D Khokhlova, Vera A Khokhlova

Extracorporeal boiling histotripsy (BH), a noninvasive method for mechanical tissue disintegration, is getting closer to clinical applications. However, the motion of the targeted organs, mostly resulting from the respiratory motion, reduces the efficiency of the treatment. Here, a practical and affordable unidirectional respiratory motion compensation method for BH is proposed and evaluated in ex vivo tissues. 

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AGA Clinical Practice Guideline on the Management of Coagulation Disorders in Patients With Cirrhosis

Robert S. O’Shea, Perica Davitkov, Cynthia W. Ko, Anita Rajasekhar, Grace L. Su, Shahnaz Sultan, Alina M. Allen, Yngve Falck-Ytter

Cirrhosis is a disease state that is accompanied by significant alterations in laboratory parameters, such as platelet count (PLT) and prothrombin time/international normalized ratio (PT/INR), routinely used to estimate clotting. Based on this measured thrombocytopenia and coagulopathy, it has traditionally been assumed that these results convey a high risk of bleeding and, therefore, significantly increased risk for patients undergoing invasive procedures. However, it has become clear that this understanding underestimates the balanced nature of alterations in hemostasis associated with end-stage liver disease, and that neither thrombocytopenia nor elevated PT/INR necessarily predicts bleeding outcomes in most of these patients.

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Survey Finds Gender Disparities Impact Both Women Mentors and Mentees in Gastroenterology

Rabinowitz, Loren Galler; Grinspan, Lauren Tal; Zylberberg, Haley; Dixon, Rebekah; David, Yakira.; Aroniadis, Olga.; Chiang, Austin; Christie, Jennifer; Fayad, Nabil; Ha, Christina; Harris, Lucinda; Ko, Cynthia; Kolb, Jennifer; Kwah, Joann; Lee, Linda; Lieberman, David; Raffals, Laura; Rex, Douglas; Shah, Shailja; Siddiqui, Uzma; Smith, Michael; Wallace, Michael; Williams, Renee; Woods, Karen; Crowe, Sheila; Kumta, Nikhil; Kim, Michelle Kang; Greenwald, David

Gastroenterologists at all levels of practice benefit from formal mentoring. Much of the current literature on mentoring in gastroenterology is based on expert opinion rather than data. In this study, we aimed to identify gender-related barriers to successful mentoring relationships from the mentor and mentee perspectives.

A voluntary, web-based survey was distributed to physicians at 20 academic institutions across the United States. Overall, 796 gastroenterology fellows and faculty received the survey link, with 334 physicians responding to the survey (42% response rate), of whom 299 (90%; 129 women and 170 men) completed mentorship questions and were included in analysis.

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Genomic and functional characterization of a mucosal symbiont involved in early-stage colorectal cancer

Melissa C. Kordahi, Ian B. Stanaway, Marion Avril, Denise Chac, Marie-Pierre Blanc, Benjamin Ross, Christian Diener, Sumita Jain, Paul McCleary, Ana Parker, Vincent Friedman, Jennifer Huang, Wynn Burke, Sean M. Gibbons, Amy D. Willis, Richard P. Darveau, William M. Grady, Cynthia W. Ko, R. William DePaolo

Colorectal cancer is a major health concern worldwide. Growing evidence for the role of the gut microbiota in the initiation of CRC has sparked interest in approaches that target these microorganisms. However, little is known about the composition and role of the microbiota associated with precancerous polyps. Here, we found distinct microbial signatures between patients with and without polyps and between polyp subtypes using sequencing and culturing techniques. We found a correlation between Bacteroides fragilis recovered and the level of inflammatory cytokines in the mucosa adjacent to the polyp.

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Gastrointestinal Bleeding at CT Angiography and CT Enterography: Imaging Atlas and Glossary of Terms

Guglielmo FF, Wells ML, Bruining DH, Strate LL, Huete Á, Gupta A, Soto JA, Allen BC, Anderson MA, Brook OR, Gee MS, Grand DJ, Gunn ML, Khandelwal A, Park SH, Ramalingam V, Sokhandon F, Yoo DC, Fidler JL.

For radiologists, interpreting CT scans in patients with GI bleeding can be challenging owing to the large number of images and the diverse potential causes of bleeding. The purpose of this pictorial review by the Society of Abdominal Radiology GI Bleeding Disease-Focused Panel is to provide a practical resource for radiologists interpreting GI bleeding CT studies that reviews the proper GI bleeding terminology, the most common causes of GI bleeding, key patient history and risk factors, the optimal CT imaging technique, and guidelines for case interpretation and illustrates many common causes of GI bleeding. A CT reporting template is included to help generate radiology reports that can add value to patient care.

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A Tailored FIT for Improved Colorectal Cancer Screening 

Dominitz JA

Colorectal cancer (CRC) is a quintessential example of a condition meriting screening on the basis of the burden of disease and availability of acceptable screening tests that are not only effective at reducing CRC incidence and death but are also cost-effective (1). The wide array of recommended tests reflects the fact that none are clearly established as the “best”. Each test has its own strengths and limitations, including burden on the screenee, harms, costs, and efficacy (2). Options range from noninvasive stool-based tests (for example, fecal immunochemical test [FIT] and stool DNA tests combined with FIT) to invasive direct visualization tests (for example, colonoscopy, flexible sigmoidoscopy, and computed tomography colonography).

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Associations Between Alcohol Use and Liver-Related Outcomes in a Large National Cohort of Patients With Cirrhosis.

Pearson MM, Kim NJ, Berry K, Moon AM, Su F, Vutien P, Green PK, Williams EC, Ioannou GN.

Alcohol use can cause hepatic necroinflammation and worsening portal hypertension in patients with cirrhosis. We aimed to evaluate the associations between degree of alcohol use and clinical liver-related outcomes according to etiology of cirrhosis. In this retrospective cohort analysis, 44,349 U.S. veterans with cirrhosis from alcohol-associated liver disease (ALD), chronic hepatitis C virus (HCV) infection, or nonalcoholic fatty liver disease were identified who completed the Alcohol Use Disorders Identification Test Consumption questionnaire in 2012. Based on this score, level of alcohol use was categorized as none, low level, or unhealthy.