Clinical and Genetic Factors Associated With Complications After Crohn's Ileocolectomy

NOD2 and Crohn's Disease Clinical Practice: From Epidemiology to Diagnosis and Therapy, Rewired

Crohn's disease (CD) is a chronic inflammatory bowel disease with a multifactorial pathogenesis involving environmental and genetic factors. Since the late 20th century, the discovery of the first susceptibility gene (NOD2, previously referred to as CARD15) for CD has paved the way for further investigations into the correlations between clinical features and genetics, and its potential impact on clinical practice has fueled the research in the last 2 decades. Recent therapeutic advancements involving novel biologic drugs and small molecules have shifted inflammatory bowel disease management from a disease-centered to a patient-centric approach. To date, the role of NOD2 has not been fully understood yet. Recent data suggest that its clinical impact may be greater than currently recognized. This review overviews the most common NOD2 variants' role in real-life clinical practice. These genetic variants increase the risk of developing the disease and can aid in tailoring diagnosis and treatment. They are associated with the stricturing phenotype and ileal involvement and increase the risk of steroid refractoriness. In the meantime, limited and inconclusive evidence exists regarding their predictive role in response to azathioprine, biologic drugs, and small molecules. Eventually, their role in increasing the risk for surgery is evident, especially in those with the L1007fs variant. If further trials will support the initial evidence reported so far, NOD2 genetic variants will emerge as possible candidates for developing precision medicine in CD.

Clinical outcomes and perioperative morbidity and mortality following segmental resections of the colon for Crohn's colitis

INTRODUCTION

Crohn's disease (CD) is a chronic inflammatory bowel disease of a multifactorial pathogenesis. Recently numerous genetic variants linked to an aggressive phenotype were identified, leading to a progress in therapeutic options, resulting in a decreased necessity for surgery. Nevertheless, surgery is often inevitable. The aim of the study was to evaluate possible risk factors for postoperative complications and disease recurrence specifically after colonic resections for CD.

PATIENTS AND METHODS

A total of 241 patients who underwent colonic and ileocaecal resections for CD at our instiution between 2008 and 2018 were included. All data was extracted from clinical charts.

RESULTS

Major complications occurred in 23.8% of all patients. Patients after colonic resections showed a significantly higher rate of major postoperative complications compared to patients after ICR (p =  < 0.0001). The most common complications after colonic resections were postoperative bleeding (22.2%), the need for revision surgery (27.4%) and ICU (17.2%) or hospital readmission (15%). As risk factors for the latter, we identified time interval between admission and surgery (p = 0.015) and the duration of the surgery (p = 0.001). Isolated distal resections had a higher risk for revision surgery and a secondary stoma (p = 0.019). Within the total study population, previous bowel resections (p = 0.037) were identified as independent risk factors for major perioperative complications.

CONCLUSION

The results indicate that both a complex surgical site and a complex surgical procedure lead to a higher perioperative morbidity in colonic resections for Crohn's colitis.

Creating a Surgical Biobank: The Hershey Medical Center Experience

BACKGROUND

Tissue harvesting at the time of surgery offers surgeons and scientists a unique opportunity to discover and better understand disease pathophysiology. Tissue biobanking presents challenges in patient consents, specimen collection, preparation, and storage, but the potential for scientific discovery justifies the effort. Although the number of tissue biobanks is increasing worldwide, information regarding necessary infrastructure, process flow, and management of expected obstacles is lacking.

OBJECTIVE

To provide a framework and motivation for clinician scientists intending to start an intestinal tissue biobank under their direction.

DATA SOURCES

The Carlino Family Inflammatory Bowel and Colorectal Diseases Biobank is housed at the Milton S. Hershey Medical Center.

STUDY SELECTION

Review.

INTERVENTION

Implementation of a surgical tissue biobank at a large tertiary care institution.

MAIN OUTCOME MEASURES

Assess critical challenges and obstacles over the years as well as keys to the success of the program.

RESULTS

Over 2 decades, the institutional biobank grew from an IBD biobank to one which now incorporates thousands of surgical specimens representing numerous colorectal diseases. This was done through a process of refinement focusing on patient recruitment and an efficient consenting and specimen management process. The biobank's success is further insured by institutional, external, and philanthropic support; scientific collaborations; and sharing of biological specimens with other groups of dedicated researchers.

LIMITATIONS

This is a single-center experience in collecting surgically resected colorectal specimens.

CONCLUSIONS

Surgical specimen biobanks are essential in studying disease cause using genomics, transcriptomics, and proteomic technologies. Therefore, surgeons, clinicians, and scientists should build biobanks at their institutions to promote further scientific discovery and improve specimen diversity.

Ileocolonic Healing after Small Ileocecal Resection in Mice: NOD2 Deficiency Impairs Anastomotic Healing by Local Mechanisms

Ileocecal resection (ICR) is frequently performed in Crohn's disease (CD). NOD2 mutations are risk factors for CD. Nod2 knockout (ko) mice show impaired anastomotic healing after extended ICR. We further investigated the role of NOD2 after limited ICR. C57B16/J (wt) and Nod2 ko littermates underwent limited ICR including 1-2 cm terminal ileum and were randomly assigned to vehicle or MDP treatment. Bursting pressure was measured on POD 5, and the anastomosis was analyzed for matrix turn-over and granulation tissue. Wound fibroblasts from subcutaneously implanted sponges were used for comparison. The M1/M2 macrophage plasma cytokines were analyzed. Mortality was not different between groups. Bursting pressure was significantly decreased in ko mice. This was associated with less granulation tissue but was not affected by MDP. However, anastomotic leak (AL) rate tended to be lower in MDP-treated ko mice (29% vs. 11%, p = 0.07). mRNA expression of collagen-1α (col1 α), collagen-3α (col3 α), matrix metalloproteinase (mmp)2 and mmp9 was increased in ko mice, indicating increased matrix turn-over, specifically in the anastomosis. Systemic TNF-α expression was significantly lower in ko mice. Ileocolonic healing is impaired in Nod2 ko mice after limited ICR by local mechanisms maybe including local dysbiosis.

Association between Taxonomic Composition of Gut Microbiota and Host Single Nucleotide Polymorphisms in Crohn's Disease Patients from Russia

Crohn's disease (CD) is a chronic relapsing inflammatory bowel disease of unknown etiology. Genetic predisposition and dysbiotic gut microbiota are important factors in the pathogenesis of CD. In this study, we analyzed the taxonomic composition of the gut microbiota and genotypes of 24 single nucleotide polymorphisms (SNP) associated with the risk of CD. The studied cohorts included 96 CD patients and 24 healthy volunteers from Russia. Statistically significant differences were found in the allele frequencies for 8 SNPs and taxonomic composition of the gut microbiota in CD patients compared with controls. In addition, two types of gut microbiota communities were identified in CD patients. The main distinguishing driver of bacterial families for the first community type are Bacteroidaceae and unclassified members of the Clostridiales order, and the second type is characterized by increased abundance of Streptococcaceae and Enterobacteriaceae. Differences in the allele frequencies of the rs9858542 (BSN), rs3816769 (STAT3), and rs1793004 (NELL1) were also found between groups of CD patients with different types of microbiota communities. These findings confirm the complex multifactorial nature of CD.

Immunity-related GTPase IRGM at the intersection of autophagy, inflammation, and tumorigenesis

The human immunity-related GTPase M (IRGM) is a GTP-binding protein that regulates selective autophagy including xenophagy and mitophagy. IRGM impacts autophagy by (1) affecting mitochondrial fusion and fission, (2) promoting the co-assembly of ULK1 and Beclin 1, (3) enhancing Beclin 1 interacting partners (AMBRA1, ATG14L1, and UVRAG), (4) interacting with other key proteins (ATG16L1, p62, NOD2, cGAS, TLR3, and RIG-I), and (5) regulating lysosomal biogenesis. IRGM also negatively regulates NLRP3 inflammasome formation and therefore, maturation of the important pro-inflammatory cytokine IL-1β, impacting inflammation and pyroptosis. Ultimately, this affords protection against chronic inflammatory diseases. Importantly, ten IRGM polymorphisms (rs4859843, rs4859846, rs4958842, rs4958847, rs1000113, rs10051924, rs10065172, rs11747270, rs13361189, and rs72553867) have been associated with human inflammatory disorders including cancer, which suggests that these genetic variants are functionally relevant to the autophagic and inflammatory responses. The current review contextualizes IRGM, its modulation of autophagy, and inflammation, and emphasizes the role of IRGM as a cross point of immunity and tumorigenesis.

It is not NOD2 - genetic and clinical risk factors for postoperative complications following ileocolic resection in Crohn's disease

PURPOSE

To evaluate the role of the nucleotide oligomerization domain 2 (NOD2) mutation status and other risk factors for the incidence of postoperative complications after ileocolic resection for Crohn's disease (CD).

METHODS

Data of 138 patients consecutively undergoing ileocolic resection for CD at a tertiary academic referral center were retrospectively analyzed including single nucleotide polymorphism (SNP) data of the NOD2 gene. Uni- and multivariate regression analysis was performed to identify factors associated with increased risk of severe postoperative complications.

RESULTS

From 114 patients (83%), the NOD2 mutation status was available. Of these, 60 (53%) had a NOD2 wildtype, whereas eleven (10%) were homozygous for the high risk p.Leu1007fsX1008 (rs2066847) variant. Major postoperative complications occurred in 28 patients (20%). Twenty-seven of these (96%) were intraabdominal septic complications such as anastomotic leakage or abscess. Male gender (P = 0.029; OR 3.052, the duration of CD (time [months] from initial diagnosis of CD to surgery; P = 0.001; OR 1.009), previous abdominal surgery for CD (P = 0.017; OR 3.49), and the presence of enteric fistulas (P = 0.023; OR 3.21) were identified as independent risk factors for major postoperative complications. Homozygosity for the NOD2 high-risk variant p.Leu1007fsX1008 did not show increased postoperative morbidity in the short and long-term outcome.

CONCLUSIONS

We could detect independent risk factors for major postoperative complications after ileocolic resection for Crohn's disease. However, patients with the high-risk variant p.Leu1007fsX1008 of the NOD2 gene did not show increased postoperative morbidity.

Influence of nutritional status in the postoperative period of patients with inflammatory bowel disease

Inflammatory bowel diseases (IBDs) are a group of chronic inflammatory diseases that affect the gastrointestinal tract, including Crohn's disease (CD) and ulcerative colitis. Surgery is a treatment option, and more than half of the patients with CD will undergo surgical interventions over the course of the disease. Postoperative complications are common in IBD patients, the most frequent being intra-abdominal sepsis, infection of the surgical site, and adynamic ileum, and nutritional status is a factor that can influence postoperative outcome. Recent studies have shown that malnutrition, obesity, sarcopenia, and myosteatosis are predictors of surgical complications. However, most were retrospective studies with small patient samples and heterogeneity of clinical and nutritional assessment methods, which limit the extrapolation of data. Therefore, knowing the pathophysiological mechanisms of IBD and identifying the best parameters for assessing nutritional status are essential for prompt implementation of adequate nutritional interventions.

Risk of postoperative infectious complications from medical therapies in inflammatory bowel disease

BACKGROUND

Medications used to treat inflammatory bowel disease (IBD) have significantly improved patient outcomes and delayed time to surgery. However, some of these therapies are recognized to increase the general risk of infection and have an unclear impact on postoperative infection risk.

OBJECTIVES

To assess the impact of perioperative IBD medications on the risk of postoperative infections within 30 days of surgery.

SEARCH METHODS

We searched the Cochrane IBD Group's Specialized Register (29 October 2019), MEDLINE (January 1966 to October 2019), Embase (January 1985 to October 2019), the Cochrane Library, ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform from inception up to October 2019, and reference lists of articles.

SELECTION CRITERIA

Randomized controlled trials, quasi-randomized controlled trials, non-randomized controlled trials, prospective cohort studies, retrospective cohort studies, case-control studies and cross-sectional studies comparing participants treated with an IBD medication preoperatively or within 30 days postoperatively to those who were not taking that medication (either another active medication, placebo, or no treatment). We included published study reports and abstracts.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts and extracted data. The primary outcome was postoperative infection within 30 days of surgery. Secondary outcomes included incisional infections and wound dehiscence, intra-abdominal infectious complications and extra-abdominal infections. Three review authors assessed risks of bias using the Newcastle-Ottawa Scale. We contacted authors for additional information when data were missing. For the primary and secondary outcomes, we calculated odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs) using the generic inverse variance method. When applicable, we analyzed adjusted and unadjusted data separately. We evaluated the certainty of the evidence using GRADE.

MAIN RESULTS

We included 68 observational cohort studies (total number of participants unknown because some studies did not report the number of participants). Of these, 48 studies reported including participants with Crohn's disease, 36 reported including participants with ulcerative colitis and five reported including participants with indeterminate colitis. All 42 studies that reported urgency of surgery included elective surgeries, with 31 (74%) of those also including emergency surgeries. Twenty-four studies had low risk of bias while the rest had very high risk. Based on pooling of adjusted data, we calculated ORs for postoperative total infection rates in participants who received corticosteroids (OR 1.70, 95% CI 1.38 to 2.09; low-certainty evidence), immunomodulators (OR 1.29, 95% CI 0.95 to 1.76; low-certainty evidence), anti-TNF agents (OR 1.60, 95% CI 1.20 to 2.13; very low-certainty evidence) and anti-integrin agents (OR 1.04, 95% CI 0.79 to 1.36; low-certainty evidence). We pooled unadjusted data to assess postoperative total infection rates for the use of aminosalicylates (5-ASA) (OR 0.76, 95% CI 0.51 to 1.14; very low-certainty evidence). One secondary outcome examined was wound-related complications in participants using: corticosteroids (OR 1.41, 95% CI 0.72 to 2.74; very low-certainty evidence), immunomodulators (OR 1.35, 95% CI 0.96 to 1.89; very low-certainty evidence), anti-TNF agents (OR 1.18, 95% CI 0.83 to 1.68; very low-certainty evidence) and anti-integrin agents (OR 1.64, 95% CI 0.77 to 3.50; very low-certainty evidence) compared to controls. Another secondary outcome examined the odds of postoperative intra-abdominal infections in participants using: corticosteroids (OR 1.53, 95% CI 1.28 to 1.84; very low-certainty evidence), 5-ASA (OR 0.77, 95% CI 0.45 to 1.33; very low-certainty evidence), immunomodulators (OR 0.86, 95% CI 0.66 to 1.12; very low-certainty evidence), anti-TNF agents (OR 1.38, 95% CI 1.04 to 1.82; very low-certainty evidence) and anti-integrin agents (OR 0.40, 95% CI 0.14 to 1.20; very low-certainty evidence) compared to controls. Lastly we checked the odds for extra-abdominal infections in participants using: corticosteroids (OR 1.23, 95% CI 0.97 to 1.55; very low-certainty evidence), immunomodulators (OR 1.17, 95% CI 0.80 to 1.71; very low-certainty evidence), anti-TNF agents (OR 1.34, 95% CI 0.96 to 1.87; very low-certainty evidence) and anti-integrin agents (OR 1.15, 95% CI 0.43 to 3.08; very low-certainty evidence) compared to controls.

AUTHORS' CONCLUSIONS

The evidence for corticosteroids, 5-ASA, immunomodulators, anti-TNF medications and anti-integrin medications was of low or very low certainty. The impact of these medications on postoperative infectious complications is uncertain and we can draw no firm conclusions about their safety in the perioperative period. Decisions on preoperative IBD medications should be tailored to each person's unique circumstances. Future studies should focus on controlling for potential confounding factors to generate higher-quality evidence.