Predictive models assessing the response to ustekinumab highlight the value of therapeutic drug monitoring in Crohn's disease

BACKGROUND

Despite the therapeutic efficacy of Ustekinumab (UST) in Crohn's disease (CD), loss of response (LOR) is observed over time. This study aims to evaluate the impact of the UST pharmacokinetics (PK) at induction on clinical and endoscopic outcomes, as well as to find predictive markers of UST response.

METHODS

This retrospective study included 80 CD patients. Pharmacokinetics data (trough levels (TLs)) combined with clinical and biological parameters were fed into tailored logistic regression and tree-based ensemble techniques to predict clinical and endoscopic outcomes at one year of follow-up.

RESULTS

TLs at week 16 were significantly lower among patients with moderate to severe endoscopic activity during the follow-up (p = 0.04). The best model to predict endoscopic outcome was obtained at week 16 by Random Forest with an area under the receiver operating characteristic curve of 0.92 ± 0.08, sensitivity 91% and specificity 75%, with key inputs such as lymphocyte and monocyte counts at week 8, and UST TLs and CRP at week 16.

CONCLUSIONS

This real-world study confirms the relationship between early UST TLs and both clinical and endoscopic outcomes. Models were developed for the task of predicting clinical and endoscopic remission in CD patients treated with UST, highlighting the clinical relevance of UST TLs at week 16.

N-acetylcysteine and glycyrrhizin combination: Benefit outcome in a murine model of acetaminophen-induced liver failure

BACKGROUND

Acetaminophen overdose is the most frequent cause of drug-induced liver failure in developed countries. Substantial progress has been made in understanding the mechanism of hepatocellular injury, but N-acetylcysteine remains the only effective treatment despite its short therapeutic window. Thus, other hepatoprotective drugs are needed for the delayed treatment of acetaminophen-induced hepatotoxicity. Our interest focused on glycyrrhizin for its role as an inhibitor of high mobility group box 1 (HMGB1) protein, a member of the family of damage-associated molecular pattern, known to play an important pathological role in various diseases.

AIM

To investigate the efficacy of the N-acetylcysteine/glycyrrhizin combination compared to N-acetylcysteine alone in the prevention of liver toxicity.

METHODS

Eight-week-old C57BL/6J wild-type female mice were used for all our experiments. Mice fasted for 15 h were treated with acetaminophen (500 mg/kg) or vehicle (phosphate-buffered saline) by intraperitoneal injection and separated into the following groups: Glycyrrhizin (200 mg/kg); N-acetylcysteine (150 mg/kg); and N-acetylcysteine/glycyrrhizin. In all groups, mice were sacrificed 12 h following acetaminophen administration. The assessment of hepatotoxicity was performed by measuring plasma levels of alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase. Hepatotoxicity was also evaluated by histological examination of hematoxylin and eosin-stained tissues sections. Survival rates were compared between various groups using Kaplan-Meier curves.

RESULTS

Consistent with data published in the literature, we confirmed that intraperitoneal administration of acetaminophen (500 mg/kg) in mice induced severe liver injury as evidenced by increases in alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase but also by liver necrosis score. Glycyrrhizin administration was shown to reduce the release of HMGB1 and significantly decreased the severity of liver injury. Thus, the co-administration of glycyrrhizin and N-acetylcysteine was investigated. Administered concomitantly with acetaminophen, the combination significantly reduced the severity of liver injury. Delayed administration of the combination of drugs, 2 h or 6 h after acetaminophen, also induced a significant decrease in hepatocyte necrosis compared to mice treated with N-acetylcysteine alone. In addition, administration of N-acetylcysteine/glycyrrhizin combination was associated with an improved survival rate compared to mice treated with only N-acetylcysteine.

CONCLUSION

We demonstrate that, compared to N-acetylcysteine alone, co-administration of glycyrrhizin decreases the liver necrosis score and improves survival in a murine model of acetaminophen-induced liver injury. Our study opens a potential new therapeutic pathway in the prevention of acetaminophen hepatotoxicity.

New insights in acetaminophen toxicity: HMGB1 contributes by itself to amplify hepatocyte necrosis in vitro through the TLR4-TRIF-RIPK3 axis

Extracellular release of HMGB1 contributes to acetaminophen-induced liver injury. HMGB1 acts as a danger-associated molecular patterns during this toxic process but the mechanisms of action and targeted cells are incompletely defined. Here we studied, in vitro, the role of HMGB1 in amplifying the acetaminophen-induced hepatocyte necrosis process. Using cultured HepaRG cells, primary human hepatocytes and selective chemical inhibitors we evaluated acetaminophen-induced toxicity. We confirmed that addition of acetaminophen induced HepaRG cell death and HMGB1 release. We showed that inhibition of HMGB1 decreased acetaminophen-induced HepaRG cell death, suggesting a feedforward effect. We provide the first evidence that exposure of HepaRG cells to recombinant human HMGB1 (rhHMGB1) also resulted in cell death. Moreover, we found that both acetaminophen and rhHMGB1 induced programmed HepaRG cell necrosis through a RIPK3-dependent mechanism. By using TLR4 blocking antibody, we demonstrated the reduction of the HepaRG cell death induced by acetaminophen and rhHMGB1. Furthermore, inhibition of TRIF, known to induce a RIPK3-dependent cell death, reduced rhHMGB1-induced HepaRG cell death. Our data support that released HMGB1 from acetaminophen-stressed hepatocytes induced necrosis of neighboring hepatocytes by TLR4-TRIF-RIPK3- pathway. This in vitro study gives new insights in the role of HMGB1 in the amplification of acetaminophen-induced toxicity.

Analysis of Genes Associated With Monogenic Primary Immunodeficiency Identifies Rare Variants in XIAP in Patients With Crohn's Disease

BACKGROUND & AIMS

A few rare monogenic primary immunodeficiencies (PIDs) are characterized by chronic intestinal inflammation that resembles Crohn's disease (CD). We investigated whether 23 genes associated with 10 of these monogenic disorders contain common, low-frequency, or rare variants that increase risk for CD.

METHODS

Common and low frequency variants in 1 Mb loci centered on the candidate genes were analyzed using meta-data corresponding to genotypes of approximately 17,000 patients with CD or without CD (controls) in Europe. The contribution of rare variants was assessed by high-throughput sequencing of 4750 individuals, including 660 early-onset and/or familial cases among the 2390 patients with CD. Variants were expressed from vectors in SW480 or HeLa cells and functions of their products were analyzed in immunofluorescence, luciferase, immunoprecipitation, and immunoblot assays.

RESULTS

We reproduced the association of the interleukin 10 locus with CD (P = .007), although none of the significantly associated variants modified the coding sequence of interleukin 10. We found XIAP to be significantly enriched for rare coding mutations in patients with CD vs controls (P = .02). We identified 4 previously unreported missense variants associated with CD. Variants in XIAP cause the PID X-linked lymphoproliferative disease type 2, yet none of the carriers of these variants had all the clinical features of X-linked lymphoproliferative disease type 2. Identified XIAP variants S123N, R233Q, and P257A were associated with an impaired activation of NOD2 signaling after muramyl dipeptide stimulation.

CONCLUSIONS

In a systematic analysis of variants in 23 PID-associated genes, we confirmed the association of variants in XIAP with CD. Further screenings for CD-associated variants and analyses of their functions could increase our understanding of the relationship between PID-associated genes and CD pathogenesis.

Combination of Gene Expression Signature and Model for End-Stage Liver Disease Score Predicts Survival of Patients With Severe Alcoholic Hepatitis

BACKGROUND & AIMS

Patients with severe alcoholic hepatitis (AH) have a high risk of death within 90 days. Corticosteroids, which can cause severe adverse events, are the only treatment that increases short-term survival. It is a challenge to predict outcomes of patients with severe AH. Therefore, we developed a scoring system to predict patient survival, integrating baseline molecular and clinical variables.

METHODS

We obtained fixed liver biopsy samples from 71 consecutive patients diagnosed with severe AH and treated with corticosteroids from July 2006 through December 2013 in Brussels, Belgium (derivation cohort). Gene expression patterns were analyzed by microarrays and clinical data were collected for 180 days. We identified gene expression signatures and clinical data that are associated with survival without liver transplantation at 90 and 180 days after initiation of corticosteroid therapy. Findings were validated using liver biopsies from 48 consecutive patients with severe AH treated with corticosteroids, collected from March 2010 through February 2015 at hospitals in Belgium and Switzerland (validation cohort 1) and in liver biopsies from 20 patients (9 received corticosteroid treatment), collected from January 2012 through May 2015 in the United States (validation cohort 2).

RESULTS

We integrated data on expression patterns of 123 genes and the model for end-stage liver disease (MELD) scores to assign patients to groups with poor survival (29% survived 90 days and 26% survived 180 days) and good survival (76% survived 90 days and 65% survived 180 days) (P < .001) in the derivation cohort. We named this assignment system the gene signature-MELD (gs-MELD) score. In validation cohort 1, the gs-MELD score discriminated patients with poor survival (43% survived 90 days) from those with good survival (96% survived 90 days) (P < .001). The gs-MELD score also discriminated between patients with a poor survival at 180 days (34% survived) and a good survival at 180 days (84% survived) (P < .001). The time-dependent area under the receiver operator characteristic curve for the score was 0.86 (95% confidence interval 0.73-0.99) for survival at 90 days, and 0.83 (95% confidence interval 0.71-0.96) for survival at 180 days. This score outperformed other clinical models to predict survival of patients with severe AH in validation cohort 1. In validation cohort 2, the gs-MELD discriminated patients with a poor survival at 90 days (12% survived) from those with a good survival at 90 days (100%) (P < .001).

CONCLUSIONS

We integrated data on baseline liver gene expression pattern and the MELD score to create the gs-MELD scoring system, which identifies patients with severe AH, treated or not with corticosteroids, most and least likely to survive for 90 and 180 days.

Infliximab Trough Levels at Induction to Predict Treatment Failure During Maintenance

BACKGROUND

Infliximab (IFX) is indicated for the treatment of inflammatory bowel diseases (IBD). Nevertheless, loss of response (LOR) to IFX is reported in up to 10% to 30% of patients within the first year of treatment. Our objective was to evaluate the impact of the pharmacokinetics of IFX at induction on treatment failure.

METHODS

This is a longitudinal cohort study on 269 patients with IBD treated with IFX in a single center. A total of 2331 blood samples were prospectively collected from 2007 until March 2015 with a retrospective analysis of clinical data. IFX trough levels (TLs) were measured by enzyme-linked immunosorbent assay. Antibodies to IFX were measured by drug-sensitive bridging assay.

RESULTS

During follow-up, patients were defined according to treatment outcome. At week 6, median IFX TL in patients requiring a switch to another treatment due to LOR (LOR switched group) (2.32 μg/mL [0.12-19.93 μg/mL]) was lower than in patients with long-term response (long-term responders) (8.66 μg/mL [0.12-12.09 μg/mL], P = 0.007) and in patients responding to optimization (LOR optimized group) (7.28 μg/mL [0.17-14.91 μg/mL], P = 0.021). At week 2, median IFX TL was lower in the LOR switched group (5.7 μg/mL [0.15-12.09 μg/mL]) compared with the long-term responders (11.92 μg/mL [0.14-19.93 μg/mL], P = 0.041) but no significant difference was reached with the LOR optimized group (11.91 μg/mL [0.23-12.09 μg/mL], P = 0.065). In the LOR switched group, median IFX TL at induction (weeks 2 and 6) was significantly lower when patients had been previously exposed to anti-tumor necrosis factor compared with naive patients (0.91 μg/mL [0.12-4.4 μg/mL] versus 6.6 μg/mL [0.15-19.93 μg/mL], P = 0.044).

CONCLUSIONS

This study suggests that patients who do not respond to any optimization strategy have lower IFX TLs during induction at week 6. IFX TLs measured early on at induction might predict treatment failure to IFX during maintenance.

Type I interferon signaling in systemic immune cells from patients with alcoholic cirrhosis and its association with outcome

BACKGROUND & AIMS

In immune cells, constitutively and acutely produced type I interferons (IFNs) engage autocrine/paracrine signaling pathways to induce IFN-stimulated genes (ISGs). Enhanced activity of IFN signaling pathways can cause excessive inflammation and tissue damage. We aimed to investigate ISG expression in systemic immune cells from patients with decompensated alcoholic cirrhosis, and its association with outcome.

METHODS

Peripheral blood mononuclear cells (PBMCs) from patients and heathy subjects were stimulated or not with lipopolysaccharide (LPS, an IFN inducer) or increasing concentrations of IFN-β. The expression of 48 ISGs and ten "non-ISG" inflammatory cytokines were analyzed using RT-qPCR.

RESULTS

We developed an 8-ISG signature (IFN score) assessing ISG expression. LPS-stimulated ISG induction was significantly lower in PBMCs from patients with cirrhosis compared to healthy controls. Non-ISGs, however, showed higher induction. Lower induction of ISGs by LPS was not due to decreased IFN production by cirrhotic PBMCs or neutralization of secreted IFN, but a defective PBMC response to IFN. This defect was at least in part due to decreased constitutive ISG expression. Patients with the higher baseline IFN scores and ISG levels had the higher risk of death. At baseline, "non-ISG" cytokines did not correlate with outcome.

CONCLUSIONS

PBMCs from patients with decompensated alcoholic cirrhosis exhibit downregulated ISG expression, both constitutively and after an acute stimulus. Our finding that higher baseline PBMC ISG expression was associated with higher risk of death, suggests that constitutive ISG expression in systemic immune cells contributes to the prognosis of alcoholic cirrhosis.

LAY SUMMARY

Enhanced activity of IFN signaling pathways can cause excessive inflammation and tissue damage. Here we show that peripheral blood mononuclear cells (PBMCs) from patients with alcoholic cirrhosis exhibit a defect in interferon-stimulated genes (ISGs). We found that higher baseline ISG expression in PBMCs was associated with higher risk of death, revealing a probable contribution of ISG expression in immune cells to the outcome of alcoholic cirrhosis.