A12 PRE-TREATMENT HLADQA1-HLADRB1 TESTING FOR THE PREVENTION OF AZATHIOPRINE-INDUCED PANCREATITIS IN INFLAMMATORY BOWEL DISEASE: A PROSPECTIVE COHORT STUDY

Background

Azathioprine (AZA) therapy has a long history of use in IBD. The need to promote its safe use in this population is ensured by governmental health policy requiring IBD patients to fail low cost drugs, such as AZA, prior to approving funding for more potent biologic therapies. AZA-induced pancreatitis is an idiosyncratic and unpredictable response, occurring in up to 7% of AZA-exposed patients that can lead to patient morbidity, hospitalization, delay in effective IBD management, as well as result in substantial additional health-related costs. There are no tools in clinical practice to identify individuals at risk of AZA-induced pancreatitis. Genetic variation in the HLADQA1-HLADRB1*07:01 haplotype is strongly associated with azathioprine (AZA)-induced pancreatitis in inflammatory bowel disease (IBD).

Aims

To evaluate whether HLA DQA1-HLADRB1*07:01A>C pre-treatment genotype testing in an adult IBD population prior to AZA therapy to guide AZA selection would result in a lower incidence of AZA-induced pancreatitis.

Methods

Participants with IBD (n=599) were screened for HLADQA1-HLADRB1*07:01A>C and participants with a variant genotype were excluded from azathioprine treatment (n=271). Wildtype participants (n=328) were started on azathioprine and followed for 3 months. The incidence of pancreatitis was compared to unscreened historical controls (n=373).

Results

The minor allele frequency of HLADQA1-HLADRB1*07:01 was 30.4% and 30.0% in the screened and unscreened populations respectively. Up to 45.2% of participants were excluded from AZA therapy based on genotype in the HLADQA1-HLADRB1*07:01A>C screened cohort. HLADQA1-HLADRB1*07:01A>C screening resulted in an 11-fold reduction in the odds of azathioprine-induced pancreatitis (0.30% versus 3.4%, OR=0.085, 95%CI=0.011–0.651, p=0.002).

Conclusions

HLA DQA1-HLADRB1*07:01A>C screening substantially reduced the risk of pancreatitis during AZA treatment in patients with IBD. However, using this strategy as a tool for guiding the use of AZA therapy in IBD may eliminate a large proportion of patients from being eligible for treatment with AZA. In regions, where there is access to other IBD therapies, and given the short and long term toxicities associated with AZA, HLA DQA1-HLADRB1*07:01A>C screening may be a clinically-relevant strategy for enhancing the safe use of AZA in IBD. Additionally, cost-effectiveness analyses are needed to further solidify the utility of HLA DQA1-HLADRB1*07:01A>C-screening in IBD populations.

Funding Agencies

Academic Medical Organization of Southwestern Ontario Innovation Fund

Right ventricular longitudinal strain measured using feature-tracking cardiac magnetic resonance is an independent predictor of all cause mortality in patients with severe tricuspid regurgitation

Introduction

Tricuspid regurgitation imposes a volume overload on the right ventricle (RV) that can lead to progressive RV dilation and dysfunction. Overt RV dysfunction is associated with poor prognosis and increased operative risk. Abnormalities of myocardial strain may provide the earliest evidence of ventricular dysfunction. CMR feature-tracking techniques now allow assessment of strain from routine cine-images, without specialized pulse sequences. Whether abnormalities of RV strain measured using CMR feature-tracking have prognostic value in patients with tricuspid regurgitation is unknown

Purpose

To evaluate the prognostic value of CMR feature-tracking derived RV free wall longitudinal strain (RVFWLS) in a large multicenter population of patients with severe tricuspid regurgitation.

Methods

Consecutive patients with severe tricuspid regurgitation undergoing CMR at four US medical centers were included in this study. Feature-tracking RVFWLS was calculated from 4 chamber cine-views (Figure-left panel). The primary endpoint was all-cause death. Cox proportional hazards regression modeling was used to examine the independent association between RVFWLS and death. The incremental prognostic value of RVFWLS was assessed in nested models.

Results

Of the 406 patients in this study,115 died during a median follow-up of 8.8 years. By Kaplan-Meier-analysis, patients with RVFWLS ≥median (−16%) had significantly reduced event free survival compared to those with RVFWLS < median (log-rank p<0.001) (Figure-right panel). By Cox multivariable regression modeling, each 1% worsening in RVFWLS was associated with a 13% increased risk-of-death after adjustement for clinical and imaging risk factors (HR=1.13 per %; p<0.001). Addition of RVFWLS in this model resulted in significant-improvement in the global-chi-square (26 to 65; p<0.0001).

Conclusions

CMR feature-tracking derived RVFWLS is an independent predictor of mortality in patients with severe tricuspid regurgitation, incremental to common clinical and imaging risk factors.

Funding Acknowledgement

Type of funding source: None

A214 GENETIC VARIATION IN THE FARNESOID X RECEPTOR PREDICTS CROHN’S DISEASE SEVERITY IN FEMALE PATIENTS

Background

Crohn’s disease (CD) is an immune-mediated inflammatory bowel disease defined by episodes of intestinal inflammation. There is now an increasing appreciation of the bile acid-sensing nuclear receptor, FXR, as an important regulator of intestinal inflammation, intestinal permeability and response to bacterial overgrowth. Many of these processes are dysregulated in CD. It is unclear how genetic variation in FXR impacts on CD severity. FXR deficiency is rare. Loss of function mutations in FXR as contributors to CD are unlikely; however, partial loss of function of FXR may contribute to CD progression or severity. Our group demonstrated that FXR-1G>T, a SNV adjacent to the ATG start codon, is linked to reduced transactivation of FXR gene targets. We hypothesized that changes in the intestinal barrier as a result of reduced FXR expression among those who harbor the FXR-1T allele are more likely to exhibit a severe CD phenotype compared to G (reference) allele carriers, and thereby experience a more rapid progression to surgery. Alterations in FXR activity may in part be secondary to genetic variation in the FXR gene.

Aims

To evaluate FXR-1G>T as a genomic biomarker of severity in CD and propose a plausible molecular mechanism.

Methods

A retrospective study (n=542) was conducted in a Canadian cohort of CD patients. Blood samples were obtained for genotypic analysis (FXR-1G>T), as well as determination of the FXR downstream product, fibroblast growth factor (FGF) 19. Primary outcomes included risk and time to first CD-related surgery. To better elucidate a potential molecular basis for the observed effect of FXR-1G>T genotype on CD prognosis (more frequent and early surgery) in female CD patients, we explored a connection between the estrogen receptor (ER)-mediated pathway and genetic variation in FXR using a cell-based model. .

Results

The FXR-1GT genotype was associated with the risk of (odds ratio, OR=3.34, 95%CI=1.58–7.05, p=0.002) and early progression to surgery (hazard ratio, HR=3.00, 95%CI=1.86–4.83, p<0.0001) in CD. Female carriers of the FXR-1GT genotype had the greatest risk of surgery (OR=14.87 95%CI=4.22–52.38, p<0.0001) and early progression to surgery (HR=6.28, 95%CI=3.62–10.90, p<0.0001). Furthermore, women carriers of FXR-1GT polymorphism had a nearly three-fold lower FGF19 plasma concentration compared to women with wildtype FXR-1GG genotype (p<0.0001). In HepG2 cells cotransfected with estrogen receptors (ERα and β) and FXR, presence of estradiol further attenuated variant FXR activity.

Conclusions

FXR-1GT is deleterious to women with CD through ER-mediated attenuation of FXR activation. Female CD FXR-1GT carriers should be considered for more aggressive medical management.

Funding Agencies

CAG, CCC, CIHR

A208 HLA-DQA1*05 GENOTYPE PREDICTS ANTI-DRUG ANTIBODY FORMATION AND LOSS OF RESPONSE DURING INFLIXIMAB THERAPY FOR INFLAMMATORY BOWEL DISEASE

Background

The underlying mechanism for immunogenicity in anti-TNFa-exposed patients with inflammatory bowel disease is poorly understood. Anti-drug antibodies are a leading contributor to infliximab loss of response and adverse drug events. Currently, it is not feasible to identify patients at risk of antibody formation prior to initiating infliximab. The genetic variation HLADQA1*05(rs2097432) has been linked to infliximab antibody formation in a cohort of patients with Crohn’s disease.

Aims

Due to the wide variation in the frequency of HLADQA1* 05 across ethnic groups, we aim to independently evaluate the association between HLADQA1*05and infliximab antibody formation, infliximab loss of response, treatment discontinuation and adverse drug events, in a Canadian inflammatory bowel disease cohort.

Methods

In a retrospective cohort study, infliximab-exposed patients with inflammatory bowel disease (n=262) were screened for the genetic variation, HLADQA1*05A>G(rs2097432). The risk of infliximab anti-drug antibody formation, infliximab loss of response, adverse events, and discontinuation were assessed in wild type (GG) and variant-carrying (AG or AA) individuals.

Results

Forty percent of all participants were HLADQA1*05A>Gvariant carriers, with 79% of participants with infliximab antibodies carrying at least one variant allele. The risk of infliximab antibody formation was higher in HLADQA1*05A>Gvariant carriers in an IBD population (adjusted HR=7.29, 95%CI=2.97–17.191, p=1.46x10-5) independent of age, sex, weight, dose and co-immunosuppression with an immunomodulator. Variant carrier status was associated with an increased risk of infliximab loss of response (adjusted HR=2.34, 95%CI=1.41–3.88, p=0.001) and discontinuation (adjusted HR=2.27, 95%CI=1.46–3.43, p=2.53x10-4) though not with infliximab-associated adverse drug events.

Conclusions

HLADQA1*05 is independently associated with a high risk of infliximab antibody formation in addition to infliximab loss of response and treatment discontinuation. As a result, we propose that pre-emptive genetic screening for the HLADQA1* 05A>Gvariant would be useful in order to predict individuals at risk of developing immunogenicity. There may be a role for genotype-guided application of combination therapy in inflammatory bowel disease.

Funding Agencies

NoneWolfe Medical Research Chair in Pharmacogenomics (MOP-89753 to RBK), the Academic Medical Organization of Southwestern Ontario (INN18-005 to RBK and AW; S17-004 to AW), and Lawson Health Research Institute (IRF-05-19 to AW)

Erythroderma with circulating atypical T-cells, likely Sézary syndrome

The erythrodermic patient is often challenging and requires careful evaluation. Work-up should include an extensive and careful medication history, histological and laboratory testing, and if necessary, molecular studies for the evaluation of underlying malignancy. Herein, we present an erythrodermic patient with repeated biopsies demonstrating a spongiotic process who was found to have circulating atypical T-cells concerning for an underlying erythrodermic T-cell leukemia, most closely related to Sézary syndrome.

3225Global longitudinal strain measured using feature-tracking cardiac magnetic resonance imaging is an independent predictor of all cause mortality in patients with preserved ejection fraction

Introduction

Ejection fraction is the principal measure used clinically to assess cardiac mechanics and provides significant prognostic information. However, echocardiographic strain imaging has shown significant abnormalities of myocardial deformation can be present despite preserved ejection fraction, which maybe associated with adverse prognosis. Cardiac-Magnetic-Resonance (CMR) feature-tracking techniques now allow assessment of strain from routine cine-images, without specialized pulse sequences. Whether abnormalities of strain measured using CMR feature-tracking have prognostic value in patients with preserved ejection fraction is unknown.

Purpose

To evaluate the prognostic value of CMR feature-tracking derived global longitudinal strain (GLS) in a large multicenter population of patients with preserved ejection fraction.

Methods

Consecutive patients with preserved ejection fraction (EF ≥50%) and a clinical indication for CMR at four US medical centers were included in this study. Feature-tracking GLS was calculated from 3 long-axis-cine-views. The primary endpoint was all-cause death. Cox proportional hazards regression modeling was used to examine the independent association between GLS and death. The incremental prognostic value of GLS was assessed in nested models.

Results

Of the 1274 patients in this study, 115 died during a median follow-up of 6.2 years. By Kaplan-Meier analysis, patients with GLS ≥ median (−20%) had significantly reduced event free survival compared to those with GLS < median (log-rank p<0.001) (Figure, top panel). The continuous relationship between GLS and the hazard of death is shown in the cubic spline (Figure, lower panel). By Cox multivariable regression modeling, each 1% worsening in GLS was associated with a 23.6% increased risk-of-death after adjustment for clinical and imaging risk factors (HR=1.236 per %; p<0.001). Addition of GLS in this model resulted in significant-improvement in the global-chi-square (67 to 168; p<0.0001) and Harrel's C-statistic (0.716 to 0.825; p<0.0001).

Conclusions

CMR feature-tracking derived GLS is a powerful independent predictor of mortality in patients with preserved ejection fraction, incremental to common clinical and imaging risk factors.

CPNE7 Induces Biological Dentin Sealing in a Dentin Hypersensitivity Model

Dentin hypersensitivity commonly occurs due to opened dentinal tubules for many reasons. In our previous study, copine 7 (CPNE7) could induce dentin formation for an indirect pulp-capping model in vivo. This study aims to investigate the formation of tertiary dentin when CPNE7 is applied to intentionally exposed dentin with nothing over it in vivo, whether it affects microleakage of the teeth, and the penetration ability of CPNE7 molecules through dentinal tubules in vitro. Cervical dentin areas of 6 maxillary incisors of 5 beagles were exposed to a class V–like lesion, and 1 side of 3 maxillary incisors was adapted with recombinant CPNE7 protein for 5 min as the experimental group. The other side was the control group, and there was no treatment of ethylenediaminetetraacetic acid (EDTA) and CPNE7 after preparation. The defects were exposed without any restorations, and all beagles were sacrificed after 4 wk. The fluid penetration of exposed dentin areas was investigated by a microleakage-testing device and confocal laser scanning microscope. Tertiary dentin formation was confirmed with histological scanning electronic microscopic analysis. Tertiary dentin formation reduces dentinal fluid flow due to occluded tubules or discontinuity with primary or secondary dentin. The in vivo hypersensitivity model with the anterior teeth of beagle dogs showed newly formed tertiary dentin at the dentin-pulp boundary in recombinant CPNE7–treated teeth when compared with the untreated control group in histologic analysis. Scanning electronic microscopic analysis revealed occluded sites with mineral deposition of intratubular dentin. In the permeability test, the mean microleakage value of the CPNE7-treated group was significantly lower than that of the control group ( P < 0.05). The tubular penetration of rhodamine B–combined CPNE7 was confirmed under confocal laser scanning microscope. CPNE7 induces formation of tertiary dentin through shallowly exposed dentinal tubules, which decreases dentin permeability.