Drug resistance in inflammatory bowel diseases

β-sitosterol alleviates dextran sulfate sodium-induced experimental colitis via inhibition of NLRP3/Caspase-1/GSDMD-mediated pyroptosis

Background: Inflammation-related NLRP3/Caspase-1/GSDMD-mediated pyroptosis is involved in the progression of ulcerative colitis (UC). β-sitosterol (SIT) was reported to have anti-inflammatory effects on experimental colitis, while the regulation of SIT on pyroptosis is unclear. Therefore, the present study aimed to define the protective and healing effects of SIT on dextran sulfate sodium (DSS)-induced experimental UC rats and human epithelial colorectal adenocarcinoma cells (Caco-2) and explore the underlying mechanisms that are responsible for its effects on NLRP3/Caspase-1/GSDMD-mediated pyroptosis in UC. Methods: UC model rats were established by oral 4% DSS. Following colitis injury, the animals received SIT (doses of 50, 100, and 200 mg/kg) treatment for 2 weeks. For in vitro study, we exposed Caco-2-50 mg/mL DSS with or without SIT (concentrations of 8 and 16 μg/mL). Disease activity index (DAI) and histopathological injury were assessed in vivo. Activation proteins of nuclear factor kappa B (NF-κB) signaling axis, and tight junction-related proteins of zonula occludens-1 (ZO-1) and occludin were detected in colon tissues. TNF-α, IL-1β, and IL-18 in serum and cell supernatant were measured by enzyme-linked immunosorbent assay (ELISA). Changes in NLRP3/Caspase-1/GSDMD-mediated pyroptosis signaling pathway activation were analyzed both in tissues and cells. Results: Our findings suggested that SIT treatment attenuated the severity of 4% DSS-induced UC by protecting rats from weight and colon length loss, and macroscopic damage. SIT also reduced proinflammatory factors production (TNF-α, IL-1β, and IL-18) in serum and cell supernatant. Mechanistically, SIT downregulated the expression levels of pyroptosis-related proteins including Caspase-1, cleaved-Caspase-1, NLRP3, GSDMD, and GSDMD-N in colon tissues and Caco-2 cells. Further analysis indicated that SIT maintained the colonic barrier integrity by enhancing the protein expression of ZO-1 and occludin. Conclusion: We confirmed that SIT exerts protective and therapeutic effects on DSS-induced colitis injury by suppressing NLRP3/Caspase-1/GSDMD-mediated pyroptosis and inflammation response. These findings demonstrated that SIT could be a potential medication for UC treatment.

Canthin-6-Ones: Potential Drugs for Chronic Inflammatory Diseases by Targeting Multiple Inflammatory Mediators

Chronic inflammatory disease (CID) is a category of medical conditions that causes recurrent inflammatory attacks in multiple tissues. The occurrence of CID is related to inappropriate immune responses to normal tissue substances and invading microbes due to many factors, such as defects in the immune system and imbalanced regulation of commensal microbes. Thus, effectively keeping the immune-associated cells and their products in check and inhibiting aberrant activation of the immune system is a key strategy for the management of CID. Canthin-6-ones are a subclass of β-carboline alkaloids isolated from a wide range of species. Several emerging studies based on in vitro and in vivo experiments reveal that canthin-6-ones may have potential therapeutic effects on many inflammatory diseases. However, no study has yet summarized the anti-inflammatory functions and the underlying mechanisms of this class of compounds. This review provides an overview of these studies, focusing on the disease entities and the inflammatory mediators that have been shown to be affected by canthin-6-ones. In particular, the major signaling pathways affected by canthin-6-ones, such as the NLR family pyrin domain containing 3 (NLRP3) inflammasome and the NF-κB signaling pathway, and their roles in several CIDs are discussed. Moreover, we discuss the limitations in studies of canthin-6-ones and provide possible solutions. In addition, a perspective that may suggest possible future research directions is provided. This work may be helpful for further mechanistic studies and possible therapeutic applications of canthin-6-ones in the treatment of CID.

Ameliorative effect of buckwheat polysaccharides on colitis via regulation of the gut microbiota

Plant polysaccharides act as prebiotics by modulating gut microbiota. However, the functional characteristics of buckwheat Fagopyrum tataricum polysaccharides (FTP) and F. esculentum polysaccharides (FEP) on colitis prevention are not valid. This study evaluated the ameliorative effects of FTP and FEP against TNBS-induced colitis via gut microbiota modulation in rats. The characterizations of FTP and FEP were analyzed, including FTIR, TGA, DSC, and monosaccharide composition. In addition, the pathological features of colon length and symptoms in TNBS-induced colitis were improved via the intragastric preadministration of FTP and FEP. The results showed that prefeeding with FTP and FEP decreased inflammatory cytokines (IL-6, IL-1β, and TNF-α), β-glucuronidase, and mucinase, as well as increasing superoxide dismutase, catalase, and glutathione peroxidase levels, in TNBS-induced rats. A decrease in inflammatory signaling-associated proteins (NF-κB, MAPK, COX-2, and iNOS) improved the treatment of TNBS-induced colitis by buckwheat polysaccharides. Moreover, prefeeding with buckwheat polysaccharides increased the Firmicutes/Bacteroidetes ratio and short-chain fatty acid (SCFA) production and decreased the abundance of inflammation-related bacteria (Oscillospiraceae and Oscillibacter). In conclusion, FTP and FEP strongly improved TNBS-induced colitis through antioxidant, anti-inflammatory, and microbiota modulation properties, especially in the high-dose FEP group. Buckwheat polysaccharides have the potential for utilization in functional ingredients or food development.

Anti-Inflammatory Potential of Brassicaceae-Derived Phytochemicals: In Vitro and In Vivo Evidence for a Putative Role in the Prevention and Treatment of IBD

Inflammatory bowel disease (IBD) is a group of intestinal disorders, of unknown etiology, characterized by chronic inflammation within the gut. They are gradually becoming critical because of the increasing incidence worldwide and improved diagnosis. Due to the important side effects observed during conventional therapy, natural bioactive components are now under intense investigation for the prevention and treatment of chronic illnesses. The Brassicaceae family comprises vegetables widely consumed all over the world. In recent decades, a growing body of literature has reported that extracts from the Brassicaceae family and their purified constituents have anti-inflammatory properties, which has generated interest from both the scientific community and clinicians. In this review, data from the literature are scrutinized and concisely presented demonstrating that Brassicaceae may have anti-IBD potential. The excellent biological activities of Brassicacea are widely attributable to their ability to regulate the levels of inflammatory and oxidant mediators, as well as their capacity for immunomodulatory regulation, maintenance of intestinal barrier integrity and intestinal flora balance. Possible future applications of bioactive-derived compounds from Brassicaceae for promoting intestinal health should be investigated.

Lycopodium Mitigates Oxidative Stress and Inflammation in the Colonic Mucosa of Acetic Acid-Induced Colitis in Rats

Inflammatory bowel diseases (IBDs) such as ulcerative colitis (UC) and Crohn’s disease (CD) are diseases of the gastrointestinal system involving genetic and environmental factors attributed to oxidative stress and inflammation. Targeting oxidative stress and inflammation by novel dietary compounds of natural origin convincingly appears to be one of the important therapeutic strategies to keep the disease in remission. As there is no permanent cure for IBD except for chronic long-term treatment or surgery, it is therefore imperative to investigate plant-based agents that are receiving attention for their therapeutic benefits to overcome the debilitating clinical conditions of IBD. Lycopodium (LYCO), a plant of tropical and subtropical origin and known by numerous names such as ground pine, club moss, or devil’s claw, has been popularly used for centuries in traditional medicine including Chinese and Indian medicines. In the present study, the effect of LYCO has been investigated in an acetic acid (AA)-induced colitis model in Wistar rats. LYCO was orally administered at the dose of 50 mg/kg/day either 3 days before or 30 min after the induction of IBD and continued for 7 days by intrarectal administration of AA. The changes in body weight and macroscopic and microscopic analysis of the colon of rats of different experimental groups were observed on days 0, 2, 4, and 7. The levels of myeloperoxidase (MPO), reduced glutathione (GSH), and malondialdehyde (MDA) were measured. AA caused a significant reduction in body weight and increased macroscopic and microscopic ulcer scores along with a significant decline in antioxidant enzymes, superoxide dismutase (SOD), and catalase and antioxidant substrate, glutathione (GSH). There was a concomitant increased formation of malondialdehyde (MDA), a marker of lipid peroxidation, and raised myeloperoxidase (MPO) activity, a marker of neutrophil activation. Treatment with LYCO significantly improved IBD-induced reduction in body weight, improved histology, inhibited MDA formation, and restored antioxidants along with reduced MPO activity. AA also caused the release of proinflammatory cytokines such as interleukin-1β (IL-1β) and interleukin-23 (IL-23). Furthermore, AA also increased the levels of calprotectin, a protein released by neutrophils under inflammatory conditions of the gastrointestinal tract. LYCO treatment significantly reduced the release of calprotectin and proinflammatory cytokines. The results demonstrate that LYCO treatment has the potential to improve disease activity by inhibiting oxidative stress, lipid peroxidation, and inflammation along with histological preservation of colonic tissues.

Pectic polysaccharides ameliorate the pathology of ulcerative colitis in mice by reducing pyroptosis

Background

Ulcerative colitis (UC) is an inflammatory bowel disease which seriously affects the quality of life of patients. There has been an increasing amount of research related to the therapeutic effects and mechanisms of natural plant substances in the treatment of recurrent UC. Rauwolfia verticillata var. Hainanensis is a medicinal plant that is native to Hainan Island, China. Some studies have documented that pectic polysaccharides (PPs) from Rauvolfia inhibited the progression of colon ulcers. However, their mechanisms of action have not been established. Studies have revealed that suppressing pyroptosis can attenuate the damage of experimental colitis. However, it is unclear whether PPs from Rauvolfia verticillata inhibit inflammation through pyroptosis. This study investigated the effects and potential mechanisms of PPs extracted from Rauvolfia verticillata on experimental UC in mice.

Methods

Male C57 mice (6–8 weeks old) were allocated into the control group, the dextran sulfate sodium (DSS)-induced UC model group (DSS group), or the DSS with pectic polysaccharides treatment group (DSS + PP group). The body weights, rectal bleeding, and stool consistencies in the mice were observed, and the disease activity index (DAI) score was calculated. Colon tissues were collected for pathological analysis by histological hematoxylin and eosin (H&E) staining. The levels of caspase-1 and interleukin (IL)-1β were detected by immunohistochemistry. Pyroptosis was assessed by transmission electron microscopy.

Results

UC in mice induced by DSS resulted in decreased general physical activity and body weight, increased DAI score, significant histological changes, inhibited caspase-1 and IL-1β expression, and promoted pyroptosis. These DSS-induced changes could be partially ameliorated by administration of PP.

Conclusions

PPs exerted an ameliorative effect on DSS-induced UC in mice by reducing pyroptosis.

A patient with ulcerative colitis treated with a combination of vedolizumab and tofacitinib

Ulcerative colitis (UC) is an inflammatory bowel disease of autoimmune origin with an estimated prevalence in Spain of 0.39%. Current treatments for UC do not achieve high long-term efficacy. Treatment recommendations in moderate and severe disease involve drugs, but when these options fail, the alternatives are scarce, and surgery is intended to be reserved for the last option. We present the case of a 48-year-old male patient with UC for 23 years, who had failed several lines of treatment. The patient started combined therapy with tofacitinib and vedolizumab. These drugs have different mechanisms of action, achieving an immune response and reducing gastrointestinal inflammation. The patient's disease symptoms improved 11 months after starting this treatment, and he is now entirely asymptomatic. Analytical parameters related to the disease have also shown improvement, and the patient has so far avoided the need for surgical intervention.

Therapeutic Potential of a Self-Assembling Peptide Hydrogel to Treat Colonic Injuries Associated with Inflammatory Bowel Disease

BACKGROUND AND AIMS

The Self-assembling Peptide Hydrogel [SAPH, PuraMatrix], a fully synthetic peptide solution designed to replace collagen, has recently been used to promote mucosal regeneration in iatrogenic ulcers following endoscopic submucosal dissection. Herein, we evaluated its utility in ulcer repair using a rat model of topical trinitrobenzene sulphonic acid [TNBS]-induced colonic injuries.

METHODS

Colonic injuries were generated in 7-week-old rats by injecting an ethanol solution [35%, 0.2 mL] containing 0.15 M TNBS into the colonic lumen. At 2 and 4 days post-injury, the rats were subjected to endoscopy, and SAPH [or vehicle] was topically applied to the ulcerative lesion. Time-of-flight secondary ion mass spectrometry [TOF-SIMS] was used to detect SAPH. Colonic expression of cytokines and wound healing-related factors were assessed using real-time polymerase chain reaction or immunohistochemistry.

RESULTS

SAPH treatment significantly reduced ulcer length [p = 0.0014] and area [p = 0.045], while decreasing colonic weight [p = 0.0375] and histological score [p = 0.0005] 7 days after injury. SAPH treatment also decreased colonic expression of interleukin [IL]-1α [p = 0.0233] and IL-6[p = 0.0343] and increased that of claudin-1 [p = 0.0486] and villin [p = 0.0183], and β-catenin staining [p = 0.0237]. TOF-SIMS revealed lesional retention of SAPH on day 7 post-injury. Furthermore, SAPH significantly promoted healing in in vivo mechanical intestinal wound models.

CONCLUSIONS

SAPH application effectively suppressed colonic injury, downregulated inflammatory cytokine expression, and upregulated wound healing-related factor expression in the rat model; thus, it may represent a promising therapeutic strategy for IBD-related colonic ulcers.

Natural-Derived Polysaccharides From Plants, Mushrooms, and Seaweeds for the Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease impairing the gastrointestinal tract, and its incidence and prevalence have been increasing over time worldwide. IBD greatly reduces peoples' quality of life and results in several life-threatening complications, including polyp, toxic colonic dilatation, intestinal perforation, gastrointestinal bleeding, and cancerization. The current therapies for IBD mainly include drugs for noncritical patients and operation for critical patients. However, continuous use of these drugs causes serious side effects and increased drug resistance, and the demand of effective and affordable drugs with minimal side effects for IBD sufferers is urgent. Natural-derived polysaccharides are becoming a research hotspot for their therapeutic effects on IBD. This study focuses on the research progress of various natural polysaccharides from plants, seaweeds, and mushrooms for the treatment of IBD during recent 20 years. Regulation of oxidative stress, inflammatory status, gut microbiota, and immune system and protection of the intestinal epithelial barrier function are the underlying mechanisms for the natural-derived polysaccharides to treat IBD. The excellent efficacy and safety of polysaccharides make them promising candidates for IBD therapy.

How Can a Polymeric Formula Induce Remission in Crohn's Disease Patients?

Crohn’s disease is an inflammatory bowel disease whose prevalence is increasing worldwide. Among medical strategies, dietary therapy with exclusive enteral nutrition is recommended as a first-line option, at least for children, because it induces clinical remission and mucosal healing. Modulen^®, a polymeric TGF-β2 enriched formula, has good palatability and is widely used. For the first time in the literature, this review outlines and discusses the clinical outcomes obtained with this therapy, as well as the potential mechanisms of action of its compounds. It can be explained by its TGF-β2 content, but also by its protein and lipid composition. Further well-designed studies are required to improve our knowledge and to optimize therapeutic strategies.

Real-world disease activity and sociodemographic, clinical and treatment characteristics of moderate-to-severe inflammatory bowel disease in Brazil

BACKGROUND

Understanding the treatment landscape of inflammatory bowel diseases (IBD) is essential for improving disease management and patient outcomes. Brazil is the largest Latin American country, and it presents socioeconomic and health care differences across its geographical regions. This country has the highest increase in IBD incidence and prevalence in Latin America, but information about the clinical and treatment characteristics of IBD is scarce.

AIM

To describe the sociodemographic, clinical, and treatment characteristics of IBD outpatients in Brazil overall and in the Southeast, South and Northeast/Midwest regions.

METHODS

Multicenter, cross-sectional study with a 3-year retrospective chart review component. Patients with moderate-to-severe Crohn's disease (CD) or ulcerative colitis (UC) were consecutively enrolled between October 2016 and February 2017. Active CD at enrollment was defined as a Harvey Bradshaw Index ≥ 8 or a CD Activity Index ≥ 220 or a calprotectin level > 200 μg/g or an active result based on colonoscopy suggestive of inadequate control during the previous year; active UC was defined as a partial Mayo score ≥ 5. Descriptive statistics were used to analyze all variables.

RESULTS

In a total of 407 included patients, CD was more frequent than UC, both overall (264 CD/143 UC patients) and by region (CD:UC ratios of 2.1 in the Southeast, 1.6 in the South and 1.2 in the Northeast/Midwest). The majority of patients were female (54.2% of CD; 56.6% of UC), and the mean ages were 45.9 ± 13.8 years (CD) and 42.9 ± 13.0 years (UC). The median disease duration was 10.0 (range: 0.5-45) years for both IBD types. At enrollment, 44.7% [95% confidence interval (CI): 38.7-50.7] of CD patients and 25.2% (95%CI: 18.1-32.3) of UC patients presented with active disease. More than 95% of IBD patients were receiving treatment at enrollment; CD patients were commonly treated with biologics (71.6%) and immunosuppressors (67.4%), and UC patients were commonly treated with mesalazine [5-Aminosalicylic acid (5-ASA)] derivates (69.9%) and immunosuppressors (44.1%). More than 50% of the CD patients had ileocolonic disease, and 41.7% presented with stricturing disease. One-quarter of CD patients had undergone CD-related surgery in the past 3 years, and this proportion was lower in the Northeast/Midwest region (2.9%).

CONCLUSION

In Brazil, there are regional variations in IBD management. CD outweighs UC in both frequency and disease activity. However, one-quarter of UC patients have active disease, and most are receiving 5-ASA treatment.

RhoA and Cdc42 in T cells: Are they targetable for T cell-mediated inflammatory diseases?

Many inflammatory diseases are not curable, necessitating a better understanding of their pathobiology that may help identify novel biological targets. RhoA and Cdc42 of Rho family small GTPases regulate a variety of cellular functions such as actin cytoskeletal organization, cell adhesion, migration, proliferation, and survival. Recent characterization of mouse models of conditional gene knockout of RhoA and Cdc42 has revealed their physiological and cell type-specific roles in a number of cell types. In T lymphocytes, which play an important role in the pathogenesis of most, if not all, of the inflammatory diseases, we and others have investigated the effects of T cell-specific knockout of RhoA and Cdc42 on T cell development in the thymus, peripheral T cell homeostasis, activation, and differentiation to effector and regulatory T cells, and on T cell-mediated allergic airway inflammation and colitis. Here we highlight the phenotypes resulting from RhoA and Cdc42 deletion in T cells and discuss whether pharmacological targeting of RhoA and Cdc42 is feasible in treating asthma that is driven by allergic airway inflammation and colitis.

Optimization of biologics to reduce treatment failure in inflammatory bowel diseases

Moderate to severe inflammatory bowel disease patients can fail to respond to conventional therapy and/or to biologic treatment. In the era of TNFα antagonists and other non-anti-TNF biologic drugs, it is important to review the literature on biologic treatment failure, which could be defined as primary non-response, secondary loss of response and intolerance. Therapeutic drug monitoring (TDM), that is, drug trough level and antidrug antibodies, should enable to determine the mechanisms of treatment failure and to optimize drug efficacy. There is a consensus on reactive TDM at the time of loss of response. Proactive TDM could be of interest during induction and/or maintenance, but randomized controlled trials are required.

Quality of life, work productivity impairment and healthcare resources in inflammatory bowel diseases in Brazil

BACKGROUND

Inflammatory bowel diseases (IBD) have been associated with a low quality of life (QoL) and a negative impact on work productivity compared to the general population. Information about disease control, patient-reported outcomes (PROs), treatment patterns and use of healthcare resources is relevant to optimizing IBD management.

AIM

To describe QoL and work productivity and activity impairment (WPAI), treatment patterns and use of healthcare resources among IBD patients in Brazil.

METHODS

A multicenter cross-sectional study included adult outpatients who were previously diagnosed with moderate to severe Crohn’s disease (CD) or ulcerative colitis (UC). At enrolment, active CD and UC were defined as having a Harvey Bradshaw Index ≥ 8 or a CD Activity Index ≥ 220 or calprotectin > 200 µg/g or previous colonoscopy results suggestive of inadequate control (per investigator criteria) and a 9-point partial Mayo score ≥ 5, respectively. The PRO assessment included the QoL questionnaires SF-36 and EQ-5D-5L, the Inflammatory Bowel Disease Questionnaire (IBDQ), and the WPAI questionnaire. Information about healthcare resources and treatment during the previous 3 years was collected from medical records. Chi-square, Fisher’s exact and Student’s t-/Mann-Whitney U tests were used to compare PROs, treatment patterns and the use of healthcare resources by disease activity (α = 0.05).

RESULTS

Of the 407 patients in this study (CD/UC: 64.9%/35.1%, mean age 42.9/45.9 years, 54.2%/56.6% female, 38.3%/37.1% employed), 44.7%/25.2% presented moderate-to-severe CD/UC activity, respectively, at baseline. Expressed in median values for CD/UC, respectively, the SF-36 physical component was 46.6/44.7 and the mental component was 45.2/44.2, the EQ-visual analog scale score was 80.0/70.0, and the IBDQ overall score was 164.0/165.0. Moderate to severe activity, female gender, being unemployed, a lower educational level and lower income were associated with lower QoL (P < 0.05). Median work productivity impairment was 20% and 5% for CD and UC patients, respectively, and activity impairment was 30%, the latter being higher among patients with moderate to severe disease activity compared to patients with mild or no disease activity (75.0% vs 10.0%, P < 0.001). For CD/UC patients, respectively, 25.4%/2.8% had at least one surgery, 38.3%/19.6% were hospitalized, and 70.7%/77.6% changed IBD treatment at least once during the last 3 years. The most common treatments at baseline were biologics (75.3%) and immunosuppressants (70.9%) for CD patients and 5-ASA compounds (77.5%) for UC patients.

CONCLUSION

Moderate to severe IBD activity, especially among CD patients, is associated with a substantial impact on QoL, work productivity impairment and an increased number of IBD surgeries and hospitalizations in Brazil.

Plant-Derived Alkaloids: The Promising Disease-Modifying Agents for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) represents a group of intestinal disorders with self-destructive and chronic inflammation in the digestive tract, requiring long-term medications. However, as many side effects and drug resistance are frequently encountered, safer and more effective agents for IBD treatment are urgently needed. Over the past few decades, a variety of natural alkaloids made of plants or medicinal herbs have attracted considerable interest because of the excellent antioxidant and anti-inflammatory properties; additionally, these alkaloids have been reported to reduce the colonic inflammation and damage in a range of colitic models. In this review paper, we summarize the recent findings regarding the anti-colitis activity of plant-derived alkaloids and emphasize their therapeutic potential for the treatment of IBD; obvious improvement of the colonic oxidative and pro-inflammatory status, significant preservation of the epithelial barrier function and positive modulation of the gut microbiota are the underlying mechanisms for the plant-derived alkaloids to treat IBD. Further clinical trials and preclinical studies to unravel the molecular mechanism are essential to promote the clinical translation of plant-derived alkaloids for IBD.