Management of ulcerative colitis: a clinical update

A Th17 cell-intrinsic glutathione/mitochondrial-IL-22 axis protects against intestinal inflammation

The intestinal tract generates significant reactive oxygen species (ROS), but the role of T cell antioxidant mechanisms in maintaining intestinal homeostasis is poorly understood. We used T cell-specific ablation of the catalytic subunit of glutamate cysteine ligase (Gclc), which impaired glutathione (GSH) production, crucially reducing IL-22 production by Th17 cells in the lamina propria, which is critical for gut protection. Under steady-state conditions, Gclc deficiency did not alter cytokine secretion; however, C. rodentium infection induced increased ROS and disrupted mitochondrial function and TFAM-driven mitochondrial gene expression, resulting in decreased cellular ATP. These changes impaired the PI3K/AKT/mTOR pathway, reducing phosphorylation of 4E-BP1 and consequently limiting IL-22 translation. The resultant low IL-22 levels led to poor bacterial clearance, severe intestinal damage, and high mortality. Our findings highlight a previously unrecognized, essential role of Th17 cell-intrinsic GSH in promoting mitochondrial function and cellular signaling for IL-22 protein synthesis, which is critical for intestinal integrity and defense against gastrointestinal infections.

Evidence of Cannabidiol Effectiveness Associated or Not with Tetrahydrocannabinol in Topical Administration: A Scope Review

Cannabis sativa is a plant of the Cannabaceae family, whose molecular composition is known for its vast pharmacological properties. Cannabinoids are the molecules responsible for Cannabis sativa potential effects, especially tetrahydrocannabinol and cannabidiol. Scientific development has shown interest in the potential of cannabidiol in various health conditions, as it has demonstrated lower adverse events and great pharmacological potential, especially when administered topically. The present study aims to carry out a scoping review, focusing on the use of cannabidiol, in vivo models, for topical administration. Thus, the methodological approach used by the Joanna Briggs Institute was applied, and the studies were selected based on previously established inclusion criteria. Even though more information regarding the dose to achieve pharmacological potential is still needed, cannabidiol demonstrated potential in treating and preventing different conditions, such as glaucoma, atopic dermatitis, epidermolysis bullosa, and pyoderma gangrenosum.

Application of Drug Repurposing Approach for Therapeutic Intervention of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), represented by Crohn's disease (CD) and ulcerative colitis (UC), is a chronic inflammatory disorder of the gastrointestinal tract (GIT) characterized by chronic relapsing intestinal inflammation, abdominal pain, cramping, loss of appetite, fatigue, diarrhoea, and weight loss. Although the etiology of IBD remains unclear, it is believed to be an interaction between genes, and environmental factors, such as an imbalance of the intestinal microbiota, changing food habits, an ultra-hygiene environment, and an inappropriate immune system. The development of novel effective therapies is stymied by a lack of understanding of the aetiology of IBD. The current therapy involves the use of aminosalicylates, immunosuppressants, and corticosteroids that can effectively manage symptoms, induce and sustain remission, prevent complications, modify the course of the disease, provide diverse treatment options, showcase advancements in biologic therapies, and enhance the overall quality of life. However, the efficacy of current therapy is overshadowed by a plethora of adverse effects, such as loss of weight, mood swings, skin issues, loss of bone density, higher vulnerability to infections, and elevated blood pressure. Biologicals, like anti-tumour necrosis factor agents, can stimulate an autoimmune response in certain individuals that may diminish the effectiveness of the medication over time, necessitating a switch to alternative treatments. The response of IBD patients to current drug therapy is quite varied, which can lead to disease flares that underlines the urgent need to explore alternative treatment option to address the unmet need of developing new treatment strategies for IBD with high efficacy and fewer adverse effects. Drug repurposing is a novel strategy where existing drugs that have already been validated safe in patients for the management of certain diseases are redeployed to treat other, unindicated diseases. The present narrative review focuses on potential drug candidates that could be repurposed for the management of IBD using on-target and off-target strategies. It covers their preclinical, clinical assessment, mechanism of action, and safety profiles, and forecasts their appropriateness in the management of IBD. The review presents useful insights into the most promising candidates for repurposing, like anti-inflammatory and anti-apoptotic troxerutin, which has been found to improve the DSS-induced colitis in rats, an antiosteoarthritic drug diacetylrhein that has been found to have remarkable ameliorating effects on DSS-induced colitis via anti-oxidant and anti- inflammatory properties and by influencing both apoptosis and pyroptosis. Topiramate, an antiepileptic and anticonvulsant drug, has remarkably decreased overall pathophysiological and histopathological events in the experimental model of IBD in rodents by its cytokine inhibitory action.

A Th17 cell-intrinsic glutathione/mitochondrial-IL-22 axis protects against intestinal inflammation

Although the intestinal tract is a major site of reactive oxygen species (ROS) generation, the mechanisms by which antioxidant defense in gut T cells contribute to intestinal homeostasis are currently unknown. Here we show, using T cell-specific ablation of the catalytic subunit of glutamate cysteine ligase (Gclc), that the ensuing loss of glutathione (GSH) impairs the production of gut-protective IL-22 by Th17 cells within the lamina propria. Although Gclc ablation does not affect T cell cytokine secretion in the gut of mice at steady-state, infection with C. rodentium increases ROS, inhibits mitochondrial gene expression and mitochondrial function in Gclc-deficient Th17 cells. These mitochondrial deficits affect the PI3K/AKT/mTOR pathway, leading to reduced phosphorylation of the translation repressor 4E-BP1. As a consequence, the initiation of translation is restricted, resulting in decreased protein synthesis of IL-22. Loss of IL-22 results in poor bacterial clearance, enhanced intestinal damage, and high mortality. ROS-scavenging, reconstitution of IL-22 expression or IL-22 supplementation in vivo prevent the appearance of these pathologies. Our results demonstrate the existence of a previously unappreciated role for Th17 cell-intrinsic GSH coupling to promote mitochondrial function, IL-22 translation and signaling. These data reveal an axis that is essential for maintaining the integrity of the intestinal barrier and protecting it from damage caused by gastrointestinal infection.

Baccharis dracunculifolia DC Hydroalcoholic Extract Improves Intestinal and Hippocampal Inflammation and Decreases Behavioral Changes of Colitis Mice

The hydroalcoholic extract of B. dracunculifolia (HEBD) and its major compound p-coumaric acid were evaluated against the severity of intestinal inflammation and behavioral changes like depressive and anxious behavior in colitis mice. Colitis was induced in Swiss mice by oral dextran sulfate sodium (DSS) administration for five days. The mice received vehicle (10 ml/kg), HEBD (3, 30, or 300 mg/kg), or p-coumaric acid (15 mg/kg) orally, once a day for twelve days. Behavioral tests were performed on the 11^th and 12^th days after the beginning of the treatments. Moreover, the colon, cortex, and hippocampus were collected to analyze oxidative and inflammatory parameters. The treatment with HEBD (300 mg/Kg), but not p-coumaric acid, showed decreased disease activity index (DAI) values compared to the vehicle group and partially preserved the villi architecture and mucin levels. Furthermore, the HEBD increased the antioxidant defenses in the colon and hippocampus and reduced the myeloperoxidase activity and IL-6 levels in the colon from colitis mice. Colitis mice treated with HEBD did not show depressive-like behavior in the tail suspension test. HEBD reduced colon inflammation, while it maintains antioxidant defenses and mucin levels in this tissue. It may reduce neuropsychiatric comorbidities associated with colitis through its antioxidant effects.

Limonene from Agastache mexicana essential oil produces antinociceptive effects, gastrointestinal protection and improves experimental ulcerative colitis

ETHNOPHARMACOLOGY RELEVANCE

Agastache mexicana is a popular plant of great demand in folk medicine, essentially due to its calming properties and for alleviating arthritic, muscular and abdominal pain. Despite its spectrum for pain relief, pharmacological studies of its bioactive constituents have been barely investigated.

AIM OF THE STUDY

To evaluate protective properties of the A. mexicana and bioactive compounds improving pathological gastrointestinal conditions in rodents.

MATERIAL AND METHODS

Different doses of the essential oil of A. mexicana ssp. mexicana and ssp. xolocotziana (30-562.2 mg/kg, i.p.) and individual monoterpenes (3-300 mg/kg, i.p.) were evaluated in an abdominal pain model. The most active monoterpene limonene and sulfasalazine (reference drug, 100 mg/kg, p.o.) were also evaluated in the oxazolone-induced colitis model using an oral gavage, where some inflammatory cytokines were analyzed by enzyme-linked immunosorbent assays. Finally, colonic histological assessment and gastroprotection in the absolute ethanol-induced ulcer model were explored.

RESULTS

Our results demonstrated that the essential oil of both subspecies produced a significant reduction in the abdominal writhes, where monoterpenes limonene and pulegone were partially responsible bioactive metabolites. Limonene showed the major antinociceptive efficacy in the writhing test. It also significantly decreased hyperalgesia, pathological biomarkers, and colonic inflammatory cytokines in the oxazolone-induced colitis model, as well as prevention in gastric damage.

CONCLUSIONS

Present results provide scientific evidence to reinforce the use of A. mexicana in the traditional medicine for gastrointestinal conditions, mainly related to pain and inflammation, demonstrating the potential of monoterpenes as natural products in the therapeutics of gastrointestinal affections such as ulcer, colitis, and abdominal pain.

Hyptis suaveolens (L.) Poit protects colon from TNBS-induced inflammation via immunomodulatory, antioxidant and anti-proliferative mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

In folk medicine Hyptis suaveolens (Lamiaceae) has been reported to relieve respiratory and gastrointestinal infections, indigestion, cold, pain, fever, cramps, skin diseases, gastric ulcer and inflammatory disorders. This study investigated the effects and the mechanisms of action of Hyptis suaveolens (L.) Poit (Lamiaceae) ethanol extract (Hs-EtOH) and hexane phase (Hs-HexF) against intestinal inflammation.

MATERIAL AND METHODS

Acute and relapse TNBS-induced ulcerative colitis protocols were used to evaluate intestinal anti-inflammatory activity. Damage evaluations, biochemical, histological and immunostaining parameters were determined.

RESULTS

Both extracts decreased macroscopic colonic inflammation and the area of lesion induced by TNBS. Nevertheless, only Hs-HexF was able to reduce colonic wall thickness, edema and diffuse inflammatory cell infiltration and to prevent GSH depletion in the acute model of ulcerative colitis. In the chronic phase with relapse of colonic ulceration, yet again only Hs-HexF significantly attenuated inflammatory parameters and presented a decrease in nitrite/nitrate, MDA, MPO, IL-1-β and TNF-α and increased levels of SOD, CAT, GSH and IL-10. Hs-HexF also significantly reduced positive cells immunostained for PCNA.

CONCLUSION

The data indicate intestinal anti-inflammatory activity for H. suaveolens, due to the participation of the antioxidant system, decreased neutrophil infiltration and cytokine modulation, as well as, owing to regulation of cell proliferation.

Revisiting Inflammatory Bowel Disease: Pathology, Treatments, Challenges and Emerging Therapeutics Including Drug Leads from Natural Products

Inflammatory bowel disease (IBD) is a chronic and life-long disease characterized by gastrointestinal tract inflammation. It is caused by the interplay of the host's genetic predisposition and immune responses, and various environmental factors. Despite many treatment options, there is no cure for IBD. The increasing incidence and prevalence of IBD and lack of effective long-term treatment options have resulted in a substantial economic burden to the healthcare system worldwide. Biologics targeting inflammatory cytokines initiated a shift from symptomatic control towards objective treatment goals such as mucosal healing. There are seven monoclonal antibody therapies excluding their biosimilars approved by the US Food and Drug Administration for induction and maintenance of clinical remission in IBD. Adverse side effects associated with almost all currently available drugs, especially biologics, is the main challenge in IBD management. Natural products have significant potential as therapeutic agents with an increasing role in health care. Given that natural products display great structural diversity and are relatively easy to modify chemically, they represent ideal scaffolds upon which to generate novel therapeutics. This review focuses on the pathology, currently available treatment options for IBD and associated challenges, and the roles played by natural products in health care. It discusses these natural products within the current biodiscovery research agenda, including the applications of drug discovery techniques and the search for next-generation drugs to treat a plethora of inflammatory diseases, with a major focus on IBD.

Gut colonization with extended-spectrum β-lactamase-producing Enterobacteriaceae may increase disease activity in biologic-naive outpatients with ulcerative colitis: an interim analysis

BACKGROUND

Certain Enterobacteriaceae strains have been associated with the development of ulcerative colitis (UC). Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae are the most commonly found multi-drug-resistant (MDR) bacteria colonizing the gut in UC patients and might trigger a more severe disease activity in UC patients.

OBJECTIVE

The aim of this study was to evaluate whether disease activity is higher in UC patients with gut colonization with ESBL-producing Enterobacteriaceae.

MATERIALS AND METHODS

A cross-sectional, pilot study was carried out in a tertiary medical center in Latvia. Demographic data were collected; UC disease activity and extent were evaluated according to the full Mayo score, Montreal classification, and adapted Truelove and Witt's index. Rectal swabs with fecal biomaterial were collected, ESBL-producing Enterobacteriaceae were isolated, and bacterial plasmid genes responsible for ESBL production, blaCTX-M, blaTEM, and blaSHV, were detected. UC disease activity was compared in patients with and without gut colonization with ESBL-producing Enterobacteriaceae.

RESULTS

A total of 65 patients with UC were included in the initial analysis. Gut colonization with ESBL-producing Enterobacteriaceae was found in seven (11%) patients - mostly Escherichia coli [5 (71%)] containing the blaCTX-M bacterial plasmid gene. Patients with gut colonization with ESBL-producing Enterobacteriaceae had more severe disease compared with patients without gut colonization according to the full Mayo score (5.86 vs. 3.40; P=0.015), Montreal classification (moderate disease vs. clinical remission; P=0.031), and adapted Truelove and Witt's index (moderate disease vs. mild disease; P=0.008).

CONCLUSION

Gut colonization with ESBL-producing Enterobacteriaceae may increase UC disease activity. Further research is needed to analyze the possible confounding factors that could contribute toward this outcome.