The role of in utero endotoxin exposure in the development of inflammatory bowel disease in mice

PROBLEM

Although early environmental influences are thought to influence the development of inflammatory bowel disease (IBD), little is known about the role of the in utero environment on subsequent IBD risk. We hypothesized that prenatal exposure to bacterial lipopolysaccharide (LPS) could modify the subsequent development of dextran sulfate sodium (DSS)-induced ulcerative colitis in adulthood by influencing the associated cellular and immune response.

METHOD OF STUDY

To test this hypothesis, we exposed developing mice in utero to LPS or saline (PBS) at E17.5, and then induced colitis at 5 weeks. We then assessed colitis severity and effects on the microbiome. In order to define the developmental impact of any potential LPS effect, we also exposed 1-week-old mice to either LPS or saline before inducing colitis at 5 weeks.

RESULTS

Mice that had been exposed to LPS but not saline in utero were protected from subsequent colitis development, and their intestinal barrier integrity and tight junction expression distribution were similar to that of control mice that were not exposed to DSS. By contrast, mice exposed to either LPS or saline at day 7 of life all developed severe colitis upon subsequent DSS exposure.

CONCLUSION

These results identify an informative time window during fetal development during which exposure to an otherwise pro-inflammatory agent like LPS protects against an inflammatory disease in adulthood.

The human milk oligosaccharides 2'-fucosyllactose and 6'-sialyllactose protect against the development of necrotizing enterocolitis by inhibiting toll-like receptor 4 signaling

BACKGROUND

Necrotizing enterocolitis (NEC) develops through exaggerated toll-like receptor 4 (TLR4) signaling in the intestinal epithelium. Breast milk is rich in non-digestible oligosaccharides and prevents NEC through unclear mechanisms. We now hypothesize that the human milk oligosaccharides 2'-fucosyllactose (2'-FL) and 6'-sialyllactose (6'-SL) can reduce NEC through inhibition of TLR4 signaling.

METHODS

NEC was induced in newborn mice and premature piglets and infant formula was supplemented with 2'-FL, 6'-SL, or lactose. Intestinal tissue was obtained at surgical resection. HMO inhibition of TLR4 was assessed in IEC-6 enterocytes, mice, and human tissue explants and via in silico modeling.

RESULTS

Supplementation of infant formula with either 2'-FL and/or 6'-SL, but not the parent sugar lactose, reduced NEC in mice and piglets via reduced apoptosis, inflammation, weight loss, and histological appearance. Mechanistically, both 2'-FL and 6'-SL, but not lactose, reduced TLR4-mediated nuclear factor kappa light-chain enhancer of activated B cells (NF-kB) inflammatory signaling in the mouse and human intestine. Strikingly, in silico modeling revealed 2'-FL and 6'-SL, but not lactose, to dock into the binding pocket of the TLR4-MD2 complex, explaining their ability to inhibit TLR4 signaling.

CONCLUSIONS

2'-FL and 6'-SL, but not lactose, prevent NEC in mice and piglet models and attenuate NEC inflammation in the human ileum, in part through TLR4 inhibition.

IMPACT

Necrotizing enterocolitis (NEC) is a major cause of morbidity and mortality in premature infants that occurs in the setting of bacterial colonization of the gut and administration of formula feeds and activation by the innate immune receptor toll-like receptor 4 (TLR4). Breast milk prevents NEC through unclear mechanisms. We now show that breast milk-enriched human milk oligosaccharides (HMOs) that are derived from lactose prevent NEC through inhibition of TLR4. The human milk oligosaccharides 2'-FL and 6'-SL, but not the backbone sugar lactose, prevent NEC in mice and piglets. 2'-FL and 6'-SL but not lactose inhibited TLR4 signaling in cultured enterocytes, in enteroids derived from mouse intestine, and in human intestinal explants obtained at the time of surgical resection for patients with NEC. In seeking the mechanisms involved, 2'-FL and 6'-SL but not lactose were found to directly bind to TLR4, explaining the inhibition and protection against NEC. These findings may impact clinical practice by suggesting that administration of HMOs could serve as a preventive strategy for premature infants at risk for NEC development.

Lifestyle behavior patterns and mortality among adults in the NHANES 1988-1994 population: A latent profile analysis

Evidence suggests interdependent associations of individual modifiable behaviors with health outcomes. However, such interrelations have not been accounted for in previous behavior-outcome associations. We conducted latent profile analysis (LPA) on self-reported levels of alcohol consumption, restaurant dining, vitamin/mineral supplement use, physical activity (PA) and smoke exposure (first- and second-hand smoke) separately for smokers (N = 4530) and non-smokers (N = 13,421) using data from the third National Health and Nutrition Examination Survey (NHANES III) to identify subgroups with similar levels within and across behaviors. Cox-proportional hazards models were used to compare mortality rates between subgroups from cancer, cardiovascular disease (CVD) and all-causes at an average of 16.4 (±6.1) years follow-up. Five behavioral typologies were identified in non-smokers ("Moderates", "Low Risk Factors", "Restaurant Diners", "Moderate Passive Smokers" and "Heavy Passive Smokers"), and four in smokers ("Moderates", "Low Risk Factors", "Heavy Smokers" and "Physically Active"). As a group, "Moderates" had levels of each behavior that were not significantly different from at least one other group. Compared to "Moderates", in non-smokers "Restaurant Diners" had lower hazard from all-cause (hazard ratio (HR):0.84, 95% CI:0.74-0.97) and CVD (HR:0.59, 0.43-0.82) mortality, while "Low Risk Factors" had higher cancer mortality (HR:1.38,1.03-1.84). In smokers, compared to "Moderates", higher hazards for mortality were found for "Heavy Smokers" (all cause: HR:1.34, 1.12-1.60; CVD: HR:1.52, 1.04-2.23; cancer: HR:1.41 1.02-1.96) and "Low Risk Factors" (all-cause: HR:1.58, 1.14-2.17). Taken together, when restaurant dining, PA and smoking exposures are grouped together, novel predictions for mortality occur, suggesting data on multiple behaviors may be informative for risk stratification.

Use of non-steroidal anti-inflammatory drugs in US adults: changes over time and by demographic

OBJECTIVE

Aspirin and non-aspirin non-steroidal anti-inflammatory drugs (NSAIDs) are preventive against cardiovascular disease (CVD) and several cancer types, but long-term use has been associated with significant health risks, resulting in conflicting recommendations on NSAID use for prevention of CVD and cancer. Previous research indicates that aspirin use increases with age and CVD risk factors and that a large percentage of the US population regularly use analgesics, including NSAIDs, but there has not been a recent, in-depth assessment of NSAID use prevalence, changes in use over time or predictors of NSAID use in the USA.

METHODS

We used the cross-sectional, National Health And Nutrition Examination Survey (NHANES) from 1988 to 1994 and three continuous cycles (1999-2004) to assess regular NSAID use prevalence, changes over time and predictors of regular NSAID use.

RESULTS

Overall, regular NSAID use increased over time and varied by demographic features. Participants over 60 years of age, women, participants with high body mass index, increased waist circumference or heart disease were significantly more likely to be regular NSAID users. By contrast, non-Hispanic African American and Mexican American participants were significantly less likely to regularly use NSAIDs.

CONCLUSIONS

This study uses a nationally representative data set (NHANES) to provide an exploration of regular NSAID use patterns over time, highlighting several demographic, lifestyle and clinical conditions associated with regular NSAID use. Understanding who is likely to regularly use NSAIDs enables more targeted messaging both for increasing the preventive benefits and for limiting the toxicities associated with regular use of NSAIDs.

Exploratory analysis of ERCC2 DNA methylation in survival among pediatric medulloblastoma patients

AIM

Medulloblastoma is the most frequent malignant pediatric brain tumor. While survival rates have improved due to multimodal treatment including cisplatin-based chemotherapy, there are few prognostic factors for adverse treatment outcomes. Notably, genes involved in the nucleotide excision repair pathway, including ERCC2, have been implicated in cisplatin sensitivity in other cancers. Therefore, this study evaluated the role of ERCC2 DNA methylation profiles on pediatric medulloblastoma survival.

METHODS

The study population included 71 medulloblastoma patients (age <18years at diagnosis) and recruited from Texas Children's Cancer Center between 2004 and 2009. DNA methylation profiles were generated from peripheral blood samples using the Illumina Infinium Human Methylation 450 Beadchip. Sixteen ERCC2-associated CpG sites were evaluated in this analysis. Multivariable regression models were used to determine the adjusted association between DNA methylation and survival. Cox regression and Kaplan-Meier curves were used to compare 5-year overall survival between hyper- and hypo-methylation at each CpG site.

RESULTS

In total, 12.7% (n=9) of the patient population died within five years of diagnosis. In our population, methylation of the cg02257300 probe (Hazard Ratio=9.33; 95% Confidence Interval: 1.17-74.64) was associated with death (log-rank p=0.01). This association remained suggestive after correcting for multiple comparisons (FDR p<0.2). No other ERCC2-associated CpG site was associated with survival in this population of pediatric medulloblastoma patients.

CONCLUSION

These findings provide the first evidence that DNA methylation within the promoter region of the ERCC2 gene may be associated with survival in pediatric medulloblastoma. If confirmed in future studies, this information may lead to improved risk stratification or promote the development of novel, targeted therapeutics.

Abstract 3704: Demographics of colorectal cancer patients vary by aspirin use

Purpose: Regular NSAID (Non-Steroidal Anti-Inflammatory Drug) use results in an overall reduction in colorectal cancer (CRC) risk; however, this reduction may vary among molecularly defined subsets of CRC. Characterization of patients by regular NSAID use and molecular subtype will provide unique insight into the biology of NSAID-based CRC prevention.

Methods: A sample of patients was selected from the Assessment of Targeted Therapies Against Colorectal Cancer (ATTACC) protocol, which is designed to molecularly profile tumors of patients with refractory metastatic CRC. Demographic data and NSAID use were collected from a risk-factor survey. Demographic characteristics were compared between 106 non-NSAID users, 75 regular aspirin users and 78 regular non-aspirin NSAID users. Chi-square analysis was used to compare categorical variables and ANOVA was used for continuous variables. Logistic regression was used to assess predictors of aspirin or non-aspirin NSAID use compared to non-use.

Results: Preliminary results indicate that aspirin users tend to be older, male and more frequently engage in vigorous physical activity compared to non-users and users of non-aspirin NSAIDs (Table I). In univariate analyses, patients who are older or engage in more frequent vigorous physical activity are at increased odds of using aspirin. When controlling for other variables, only age at diagnosis predicts aspirin use.

Table 1.Description and AssociationsNo NSAID useAspirin useNon-Aspirin usep valueN1067578Age at Stage IV Diagnosis, Mean (SE)55.2 (1.0)59.5 (1.1)53.1 (1.3)0.0006Gender, N (%)11884810.0251Male72 (61.0)59 (72.8)44 (52.4)Female46 (39.0)22 (27.2)40 (47.6)Vigorous Physical Activity, N (%)11780840.0214Little or none50 (42.7)18 (22.5)34 (40.5)Once/week10 (8.6)14 (17.5)13 (15.5)Twice/week or more57 (48.7)48 (60.0)37 (44.1)Logistic RegressionUnadjusted Odds of Aspirin UseAdjusted Odds of Aspirin Use*OR (95% CI)p valueOR (95% CI)p valueAge at Stage IV Diagnosis1.047 (1.013, 1.081)0.00571.049 (1.014, 1.085)0.0055Gender (Female)0.584 (0.316, 1.078)0.08550.701 (0.356, 1.379)0.3032Vigorous Physical Activity (overall effect)0.00850.0486Little or none (Ref)1.001.00Once/week3.889 (1.468, 10.300)0.03692.481 (0.892, 6.906)0.2997Twice/week or more2.339 (1.207, 4.533)0.58952.305 (1.137, 4.673)0.2662*Each variable is adjusted for the other variables in the table

Conclusions: These preliminary data indicate that we will be able to distinguish aspirin users from non-NSAID users in a sample of late-stage CRC patients. Going forward, we will combine these demographic data with tumor molecular classification to determine the subtypes of CRC that are more or less prevalent in aspirin/NSAID users. Use of NSAIDs and overall survival will also be evaluated among different molecular subtypes of CRC. This data, combined with analysis of risk factors for each molecular subtype will provide unique insight into the biology of NSAID-based CRC prevention.

Citation Format: Jennifer S. Davis, Shailesh Advani, Emilyn Banfield, Michael Overman, Zhi-Qin Jiang, Shanequa Manuel, Carrie Daniel, Shine Chang, Scott Kopetz. Demographics of colorectal cancer patients vary by aspirin use. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3704. doi:10.1158/1538-7445.AM2015-3704

Genetic and phenotypic effects of phonological short-term memory and grammatical morphology in specific language impairment

Deficits in phonological short-term memory and aspects of verb grammar morphology have been proposed as phenotypic markers of specific language impairment (SLI) with the suggestion that these traits are likely to be under different genetic influences. This investigation in 300 first-degree relatives of 93 probands with SLI examined familial aggregation and genetic linkage of two measures thought to index these two traits, non-word repetition and tense marking. In particular, the involvement of chromosomes 16q and 19q was examined as previous studies found these two regions to be related to SLI. Results showed a strong association between relatives' and probands' scores on non-word repetition. In contrast, no association was found for tense marking when examined as a continuous measure. However, significant familial aggregation was found when tense marking was treated as a binary measure with a cut-off point of -1.5 SD, suggestive of the possibility that qualitative distinctions in the trait may be familial while quantitative variability may be more a consequence of non-familial factors. Linkage analyses supported previous findings of the SLI Consortium of linkage to chromosome 16q for phonological short-term memory and to chromosome 19q for expressive language. In addition, we report new findings that relate to the past tense phenotype. For the continuous measure, linkage was found on both chromosomes, but evidence was stronger on chromosome 19. For the binary measure, linkage was observed on chromosome 19 but not on chromosome 16.

Glucocorticoids contribute to the heritability of leptin in Scottish adult female twins

OBJECTIVE

The precise interactions between glucocorticoids and leptin are complex and poorly understood. The aim of the study was to investigate whether the glucocorticoid/leptin interaction is influenced by shared environmental or genetic factors.

DESIGN

We investigated the heritability of body mass index (BMI), circulating leptin and urinary glucocorticoid metabolites [tetrahydrocortisol (THF), alloTHF and tetrahydrocortisone (THE)] in 54 monozygotic (MZ) and 39 dizygotic (DZ) female twins. Analysis was performed using a structural equation modelling package Mx, developed by Neale.

RESULTS

Leptin and BMI showed substantial heritability (68.3% and 71.3%, respectively). Bivariate analysis indicated that the genetic determinants of BMI and leptin are partly shared. Total cortisol metabolites (THF + alloTHF + THE), the (THE + alloTHF)/THE ratio [a marker of 11beta-hydroxysteroid dehydrogenase (11HSD) activity] and the alloTHF/THF ratio (marker for 5alpha-reductase activity) followed an environmental pattern. The heritability of leptin was significantly lowered to 63.8% (P = 0.012) when values were corrected for the influence of total cortisol metabolites but unaffected by markers of 11HSD and 5alpha-reductase activity.

CONCLUSIONS

We confirm that the genetic influence on both BMI and the circulating leptin concentration is substantial and show that these genetic determinants are highly correlated. These genetic factors, which are more likely to be dominant than additive, can be modestly but significantly modified by urinary total cortisol metabolites implying an adrenal influence.