Use of blood based biomarkers in the evaluation of Crohn's disease and ulcerative colitis

Despite significant improvements in our understanding of Crohn's disease(CD) and ulcerative colitis(UC) in recent years, questions remain regarding the best approaches to assessment and management of these chronic diseases during periods of both relapse and remission. Various serologic biomarkers have been used in the evaluation of patients with both suspected and documented inflammatory bowel disease(IBD), and while each has potential utility in the assessment of patients with IBD, potential limitation remain with each method of assessment. Given these potential shortcomings, there has been increased interest in other means of evaluation of patients with IBD, including an expanding interest in the role of gene expression profiling. Among patients with IBD, gene expression profiles obtained from whole blood have been used to differentiate active from inactive CD, as well as to differentiate between CD, UC, and non-inflammatory diarrheal conditions. There are many opportunities for a non-invasive, blood based test to aid in the assessment of patients with IBD, particularly when considering more invasive means of evaluation including endoscopy with biopsy. Furthermore, as the emphasis on personalized medicine continues to increase, the potential ability of gene expression analysis to predict patient response to individual therapies offers great promise. While whole blood gene expression analysis may not completely replace more traditional means of evaluating patients with suspected or known IBD, it does offer significant potential to expand our knowledge of the underlying genes involved in the development of these diseases.

Pre-lung transplant measures of reflux on impedance are superior to p H testing alone in predicting early allograft injury

AIM:To evaluate pre-lung transplant acid reflux on p H-testing vs corresponding bolus reflux on multichannel intraluminal impedance(MII) to predict early allograft injury.METHODS:This was a retrospective cohort study of lung transplant recipients who underwent pretransplant combined MII-p H-testing at a tertiary care center from January 2007 to November 2012. Patients with pre-transplant fundoplication were excluded. Time-to-event analysis was performed using a Cox proportional hazards model to assess associations between measures of reflux on MII-p H testing and early allograft injury. Area under the receiver operating characteristic(ROC) curve(c-statistic) of the Cox model was calculated to assess the predictive value of each reflux parameter for early allograft injury. Six p H-testing parameters and their corresponding MIImeasures were specified a priori. The p H parameters were upright,recumbent,and overall acid reflux exposure; elevated acid reflux exposure; total acid reflux episodes; and acid clearance time. The corresponding MII measures were upright,recumbent,and overall bolus reflux exposure; elevated bolus reflux exposure; total bolus reflux episodes; and bolus clearance time.RESULTS:Thirty-two subjects(47% men,mean age:55 years old) met the inclusion criteria of the study. Idiopathic pulmonary fibrosis(46.9%) repres e n t e d t h e m o s t c o m m o n p u l m o n a r y d i a g n o s i s leading to transplantation. Baseline demographics,pre-transplant cardiopulmonary function,number of lungs transplanted(unilateral vs bilateral),and posttransplant proton pump inhibitor use were similar between reflux severity groups. The area under the ROC curve,or c-statistic,of each acid reflux parameter on pre-transplant p H-testing was lower than its bolus reflux counterpart on MII in the prediction of early allograft injury. In addition,the development of early allograft injury was significantly associated with three pre-transplant MII measures of bolus reflux:overall reflux exposure(HR = 1.18,95%CI:1.01-1.36,P = 0.03),recumbent reflux exposure(HR = 1.25,95%CI:1.04-1.50,P = 0.01) and bolus clearance(HR = 1.09,95%CI:1.01-1.17,P = 0.02),but not with any p Htesting parameter measuring acid reflux alone.CONCLUSION:Pre-transplant MII measures of bolus reflux perform better than their p H-testing counterparts in predicting early allograft injury post-lung transplantation.