Inflammatory Potential of the Diet and Incidence of Crohn's Disease and Ulcerative Colitis in the EPIC-Spain Cohort

Polyphyllin Ⅵ modulates macrophage polarization through autophagy-NLRP3 inflammasome to alleviate inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract with a rising global prevalence. If left untreated, it can result in severe complications, including colon cancer. Key factors in IBD pathogenesis include macrophages, NOD-like receptor thermal protein domain associated protein 3 (NLRP3), and autophagy. Polyphyllin Ⅵ (PPⅥ), a metanoidal saponin derived from the traditional Chinese herb Chonglou, exhibits significant anti-inflammatory and anti-cancer properties, making it a compound of considerable therapeutic interest.

PURPOSE

The present study investigated the relevant mechanism of PPⅥ on protecting IBD from the perspective of NLRP3 as well as macrophage immunomodulation and laid a theoretical foundation for the development of novel IBD therapeutic drugs.

METHODS

The IBD mice were prepared by dextran sodium sulfate, and RAW 264.7 inflammatory cells were established through LPS and ATP stimulation. The indicators of macrophage polarization, NLRP3, and autophagy were detected using Western Blot, RT-qPCR, H&E staining, immunofluorescence, and flow cytometry.

RESULTS

PPⅥ can enhance the inflammatory state of LPS-induced RAW264.7 macrophages, which can reduce weight loss, decrease DAI score, increase colon length, reduce oxidative stress, and decrease intestinal epithelial barrier damage, and thus diminish inflammatory injury in DSS-induced IBD mice. PPⅥ can modify intestinal inflammation and injury by modulating macrophage function. The administration of PPⅥ can maintain the balance between M1-type macrophages and M2-type macrophages while regulating the intestinal macrophage polarization via the NLRP3 inflammasome and autophagy through wildtype mice, cells, and Nlrp3-/- mice.

CONCLUSION

PPⅥ can regulate macrophage polarization through autophagic modulation of NLRP3 inflammasome to promote the repair of intestinal epithelial damage and maintain the integrity of the mucosal barrier, which contributes to the attenuation of inflammatory injury in DSS-induced IBD mice and provides a database for the development of novel clinical drugs.

INNOVATIONS

1. This subject discovered the protective effect of PPⅥ on IBD mice. 2. This subject proved that macrophages have an important role in the intestinal protection of PPⅥ in IBD mice, and PPⅥ can inhibit the polarization of M1-type macrophages and promote the polarization of M2-type macrophages. 3. This subject demonstrated that PPⅥ could regulate macrophage polarization through NLRP3 inflammasome and ameliorate intestinal inflammation in vitro, in vivo, and in Nlrp3-/- mice. 4. This subject confirmed that PPⅥ could regulate macrophage polarization to alleviate inflammatory injury by inhibiting NLRP3 inflammasome through modulating autophagy in vitro, in vivo, and the application of inhibitors. 5. This study explored the developmental value of PPⅥ and laid the theoretical foundation for the development of novel therapeutic drugs as well as therapeutic strategies for IBD.

Dietary Patterns and Risk of Inflammatory Bowel Disease: A Systematic Review of Observational Studies

BACKGROUND

The incidence of inflammatory bowel disease (IBD) is increasing worldwide. Dietary patterns may be associated with odds of this disease. Although previous reviews have attempted to summarize the evidence in this field, the growing body of investigations prompted us to conduct an updated comprehensive systematic review.

METHODS

We used the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines to evaluate the association between dietary patterns before disease onset and the risk of IBD. PubMed, SCOPUS, and Web of Science were searched using structured keywords up to November 20, 2023.

RESULTS

Twenty-four publications (13 case-control, 1 nested case-control, and 10 cohort studies) were included in this review. The sample size of these studies ranged from 181 to 482 887 subjects. The findings were inconsistent across the included studies, showing inverse, direct, or no association between different dietary patterns and the risk of IBD.

CONCLUSIONS

This review provides comprehensive data on the link between dietary patterns prior to IBD diagnosis and risk of this condition. The explicit finding of present review is the extent gap in our knowledge in this field. Therefore, large-scale, high-quality studies are warranted to improve our understanding of the relationship between dietary patterns and IBD risk.

Life's essential 8, genetic susceptibility, and risk of inflammatory bowel diseases: a population-based cohort study

BACKGROUND

Evidence has shown that the individual metrics in Life's Essential 8 (LE8), an updated cardiovascular health (CVH) concept proposed by the American Heart Association, play a role in the development of inflammatory bowel disease (IBD). However, epidemiological evidence on the overall LE8 on IBD risk remains limited. We aimed to assess the longitudinal associations of LE8-defined CVH and the risks of IBD and its subtypes, ulcerative colitis (UC) and Crohn's disease (CD). We also tested whether genetic susceptibility could modify these associations.

METHODS

A total of 260,836 participants from the UK Biobank were included. LE8 scores were determined by 8 metrics (physical activity, diet, nicotine exposure, sleep, body mass index, blood pressure, blood glucose, and blood lipids), and were divided into three levels: low CVH (0-49), moderate CVH (50-79), and high CVH (80-100). Cox proportional hazards models were used to calculate the hazard ratios (HRs) and confidence intervals (CIs) of the risk of IBD in relation to CVH status.

RESULTS

Over a median follow-up 12.3 years, we documented 1,500 IBD cases (including 1,070 UC and 502 CD). Compared to participants with low CVH, the HRs (95% CIs) of those with high CVH for IBD, UC, and CD were 0.67 (0.52, 0.83), 0.70 (0.52, 0.93), and 0.55 (0.38, 0.80), respectively. These associations were not modified by genetic susceptibility (all P for interactions > 0.05). The lowest HR (UC: 0.30, 95% CI: 0.20-0.45; CD: 0.33, 95% CI: 0.20-0.57) was observed in participants with both high CVH and low genetic risk.

CONCLUSIONS

Better CVH, defined by LE8, was associated with significantly lower risks of IBD, UC, and CD, irrespective of genetic predisposition. Our results underscore the importance of adherence to LE8 guidelines for maintaining CVH as a potential strategy in the prevention of IBD.

Role of diet in prevention versus treatment of Crohn's disease and ulcerative colitis

Diet is a modifiable risk factor for disease course and data over the past decade have emerged to indicate its role in Crohn's disease (CD) and ulcerative colitis (UC). However, literature is riddled with misinterpretation of data, often leading to unexpected or conflicting results. The key understanding is that causative factors in disease development do not always proceed to an opportunity to change disease course, once established. Here, we discuss the data on dietary influences in three distinct disease states for CD and UC-predisease, active disease and quiescent disease. We appraise the literature for how our dietary recommendations should be shaped to prevent disease development and if or how that differs for CD and UC induction therapy and maintenance therapy. In UC, principles of healthy eating are likely to play a role in all states of disease. Conversely, data linking dietary factors to CD prevention and treatment are paradoxical with the highest quality evidence for CD treatment being exclusive enteral nutrition, a lactose, gluten and fibre-free diet comprising solely of ultraprocessed food-all dietary factors that are not associated or inversely associated with CD prevention. High-quality evidence from dietary trials is much awaited to expand our understanding and ultimately lead our dietary recommendations for targeted patient populations.

Associations of dietary patterns between age 9 and 24 months with risk of celiac disease autoimmunity and celiac disease among children at increased risk

BACKGROUND

Higher gluten intake in childhood is associated with increased incidence of celiac disease autoimmunity (CDA) and celiac disease. It remains to be studied whether different dietary patterns independent of gluten intake contribute to the incidence.

OBJECTIVES

This study aimed to explore associations of dietary patterns by age 2 y with risk of CDA and celiac disease in genetically susceptible children.

METHODS

Data was used from 6726 participants at genetic risk of type 1 diabetes and celiac disease enrolled in the observational cohort, The Environmental Determinants of Diabetes in the Young (TEDDY) study. Children were annually screened for tissue transglutaminase autoantibodies (tTGAs) from age 2 y. Principal component analysis extracted dietary patterns, based on intake of 27 food groups assessed by 3-d food records at age 9 to 24 mo. The primary outcome was CDA (i.e., persistently tTGA-positive in at least 2 consecutive samples), and the secondary outcome was celiac disease. During follow-up to mean age 11.0 (standard deviation 3.6) y, 1296 (19.3%) children developed CDA, and 529 (7.9%) were diagnosed with celiac disease. Associations of adherence to dietary patterns (per 5-unit increase) with the study outcomes were estimated by Cox regression models adjusted for risk factors including gluten intake.

RESULTS

At age 9 mo, a dietary pattern higher in the food groups vegetable fats and milk was associated with reduced risk of CDA (hazard ratio [HR]: 0.88; 95% confidence interval [CI]: 0.79, 0.98; P = 0.02). At 24 mo, a dietary pattern higher in the food groups wheat, vegetable fats, and juices, and lower in milk, meat, and oats at age 24 mo was associated with increased risk of CDA (HR: 1.18; 95% CI: 1.05, 1.33; P < 0.001) and celiac disease (HR: 1.24; 95% CI: 1.03, 1.50; P = 0.03).

CONCLUSIONS

Dietary patterns in early childhood are associated with risk of CDA and celiac disease in genetically predisposed children, independent of gluten intake.

Associations between dietary inflammatory scores and biomarkers of inflammation in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort

BACKGROUND

Since the first version of the dietary inflammatory index (DII®) developed in the past decade, several other versions have been developed. However, to date no study has attempted to compare these versions with respect to their associations with biomarkers of inflammation.

OBJECTIVE

We aimed to investigate the relationship between four dietary inflammatory scores [DII, two energy-adjusted derivatives (E-DII and E-DIIr), and the Inflammatory Score of the Diet (ISD)], and circulating levels of several inflammatory markers and adipokines.

METHODS

This study included 17 637 participants from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort with at least one marker of inflammation measured in blood. Associations between the four scores and C-reactive protein (CRP), interleukin (IL)6, IL10, IL1RA, tumor necrosis factor-α (TNFα), soluble tumor necrosis factor receptor-1 (sTNFR1), sTNFR2, leptin, soluble leptin receptor (sLeptin R), adiponectin, and High Molecular Weight (HMW) adiponectin were evaluated using multivariable linear regressions adjusted for potential confounders.

RESULTS

Positive associations were observed between the four dietary inflammatory scores and levels of CRP, IL6, sTNFR1, sTNFR2 and leptin. However, only the DII and the ISD were positively associated with IL1RA levels and only the DII and the E-DIIr were positively associated with TNFα levels. The proportion of variance of each biomarker explained by the scores was lower than 2%, which was equivalent to the variance explained by smoking status but much lower than that explained by body mass index.

CONCLUSIONS

Our results suggest that the four dietary inflammatory scores were associated with some biomarkers of inflammation and could be used to assess the inflammatory potential of diet in European adults but are not sufficient to capture the inflammatory status of an individual. These findings can help to better understand the inflammatory potential of diet, but they need to be replicated in studies with repeated dietary measurements.