Introduction

Antidepressants are an integral part of the treatment of IBS as a disorder of gut-brain interaction (DGBI). Accordingly also a direct interaction with the gut microbiota might be relevant as an additional mode of action. With its high content of flavonoids, a substance group for which beneficial neuromodulatory effects, mediated by the microbiota, are known. St. John's wort extract, an antidepressant with clinically proven therapeutic equivalence to TCAs and SSRIs, could be a promising candidate for such an additional action, also as there is a history of use also in GI complaints.

Aims & Methods

Aim was to follow the test substance, a St. John's wort extract (STW 3-VI), with clinically proven anti-depressant activity [1] and standardized flavonoid content [2], through the GI tract. According to the Infogest protocol [3,4], first the influence of the upper GI digestion on the extract was modelled by subsequent incubaton with respective enzymes and buffer mixes. The predigested extract was subsequently incubated with fecal samples from ten healthy donors (24h, anoxic, 37°C). The metabolism of the flavonoids by the gut microbiota was captured by UHPLC-HRMS, and also proteolytic markers (BCFA and ammonium) were measured by GC-FID and IPB colorimetric analysis. 16S rRNA gene sequencing was used to assess shifts in microbial community composition, followed by functional analysis via ATLAS, using KEGG, Cazy and Pfam for annotations.

Results

All major extract constituents were stable towards upper intestinal tract digestion. They were, however, readily catabolized by the gut microbiota. Metabolites of the flavonoids included taxifolin, hydroxyphenylpropionic acids and protocatechuic acid. Proteolytic markers were significantly decreased. Differential abundance analysis of the microbial communities showed that several taxa were significantly modulated by the extract, with e.g. Bacteroides (p=0.005) Marinifilaceae (p=0.0007) and Prevotellaceae (p=0.035) decreasing. Functional analysis revealed 540 differently expressed genes (p<0.01), some involved in flavonoid metabolism.

Conclusion

Beyond the known antidepressant activity of St. John's wort extract, its components are also prodrugs for substances with potential therapeutic benefits in IBS as well as in psychic depression [5]. This is in accordance to the results of the functional analysis of the gut microbiota, given that changes of abundance of bacterial taxa by the treatment antagonize abundance shifts described in depressive as well as IBS patients [6]. The decrease of proteolytic markers is also in line with a beneficial action in IBS [7]. In conclusion, St. John's wort might, beyond its known efficacy in mild to moderate depression, also be a promising therapeutic option in IBS patients, especial with co-occurring depressive symptoms.

References

1. Gastpar M, Singer A, Zeller K. Efficacy and tolerability of hypericum extract STW3 in long-term treatment with a once-daily dosage in comparison with sertraline. Pharmacopsychiatry. 2005;38:78-86.
2. www.ema.europa.eu/en/medicines/herbal/hyperici-herba
3. Brodkorb A, Egger L, Alminger M, et al. INFOGEST static in vitro simulation of gastrointestinal food digestion. Nat Protoc 2019; 14: 991-1014.
4. Pérez-Burillo S, Molino S, Navajas-Porras B. et al. An in vitro batch fermentation protocol for studying the contribution of food to gut microbiota composition and functionality. Nat Protoc 2021; 16: 3186–3209.
5. Vissiennon C, Nieber K, Kelber O, Butterweck V. Route of administration determines the anxiolytic activity of the flavonols kaempferol, quercetin and myricetin -- are they prodrugs? J Nutr Biochem. 2012; 23: 733-740
6. Duan R, Zhu S, Wang B, Duan L. Alterations of gut microbiota in patients with irritable bowel syndrome based on 16S rRNA-targeted sequencing: A Systematic Review. Clin Transl Gastroenterol. 2019; 10:e00012.
7. Hou JJ, Wang X, Li Y, Su S, Wang YM, Wang BM. The relationship between gut microbiota and proteolytic activity in irritable bowel syndrome. Microb Pathog. 2021; 157:104995.

Disclosure

MEG, EMPF and RB have received fees from Steigerwald Arzneimittelwerk GmbH, Darmstadt, Germany, HEK and OK are employees of the same company.

Introduction

Wee1 negatively regulates the G2/M checkpoint of the cell cycle, inhibiting cells with DNA damage from entering mitosis and inducing apoptosis. Although efficacy of Wee1 inhibitors as single agents or in combination with other agents has been reported in a variety of carcinomas and the association between Wee1 inhibitors and tumor immunity has been reported, the effect of Wee1 inhibitors on the tumor immune microenvironment in colorectal cancer (CRC) has not been clarified. Since p53 and KRAS are involved in cell cycle regulation at the G1/S checkpoint, mutations in them may increase dependence on the G2/M checkpoint for DNA repair, making Wee1 inhibitors more effective.

Aims & Methods

This study aimed to clarify the association between Wee1 expression and clinicopathological features in CRC and the effect of Wee1 inhibitors on the tumor immune microenvironment in CRC. Study 1: We performed immunostaining on 152 CRC cases surgically resected at our hospital between May 2013 and February 2015, and classified them into positive and negative groups according to the degree of Wee1 expression and investigated the association between Wee1 expression and clinicopathological features. Study 2: We measured Wee1 expression levels by Realtime PCR on 10 human-derived CRC cell lines and 2 mouse-derived CRC cell lines. We examined the effect of Wee1 inhibitor (AZD1775) on cell proliferation using Timelapse system. We examined the effect of Wee1 inhibitor on cell cycle using Cell Cycle Analysis Kit. We examined the effects of Wee1 inhibitor on apoptosis induction were examined using the Apoptosis Detection Kit. Study 3: We created the CRC orthotopic transplantation mouse model by transplanting the CRC cell line MC38 derived from C57BL/6 mice into the cecum of mice, comparing the tumor sizes of the control and treatment groups treated with Wee1 inhibitor for 21 days, and evaluating the effect of Wee1 inhibitor on the tumor immune microenvironment by immunostaining and RNA sequencing of mice tumor specimens.

Results

Study 1: No significant association was found between Wee1 expression and clinicopathological features or prognosis. However, overall survival rate was significantly higher in Wee1 positive and KRAS-mutant patients compared to Wee1 negative and KRAS wild-type patients. Study 2: Real time PCR showed that Wee1 expression was higher in most CRC cell lines than in normal colon mucosa. Wee1 inhibitor attenuated cell proliferation in a concentration-dependent manner in all CRC cell lines, and the effect was independent on Wee1 expression level. Cell cycle analysis showed that the percentage of cells in G2/M phase increased after exposure to Wee1 inhibitor, especially in cell lines with both p53 and KRAS mutations. In addition, the number of apoptotic cells increased after exposure to Wee1 inhibitor, but in the cell lines with KRAS mutation and p53 wild type, the number of apoptotic cells did not increase. Study 3: In the orthotopic transplanted mouse model, tumor volume was significantly smaller in the treated group compared to the control group, and immunohistological examination and RNA sequencing of mice tumor specimens showed enhanced tumor immunity and suppressed stromal reaction.

Conclusion

Wee1 inhibitor attenuated CRC cell proliferation through modulating cell cycle, especially in cell lines with p53 mutation and attenuated tumor growth via enhancement of tumor immune response and suppression of stromal reaction in orthotopic transplanted mouse model. Wee1 inhibitor AZD1775 could be the promising treatment option for CRC.

Introduction

Piecemeal endoscopic mucosal resection (pEMR) is the preferred treatment for large non-pedunculated colorectal polyps (LNPCPs)[1,2]. A major limitation of pEMR is residual or recurrent adenoma (RRA), which was reported to in 15%-30% of cases at first surveillance colonoscopy (SC1)[3], performed 3-6 months after the index procedure, but is reduced to the range of 3%-5% by applying ablative measures to the post-EMR resection margin[4].

Aims & Methods

This study aimed to evaluate the effects of late SC1 on RRA.
This is an analysis of a prospectively collected cohort of adult patients referred for pEMR at two academic centers in Israel, from 2016 to 2023. We included all patients who underwent pEMR of LNCPCs and completed SC1.
We compared outcomes between patients who completed early SC1 at 3-6 months following the index procedure with patients who completed late SC1 later than 6 months. All procedures and surveillance colonoscopies were performed by experienced endoscopists trained in pEMR using high-definition scopes. EMR was followed by thermal ablation of the entire mucosal defect margin with snare soft tip coagulation, as previously described[4].
Scar evaluation at SC1 was performed with high-definition white light and chromoendoscopy. Our primary endpoint was RRA at SC1.
Analyses were performed per lesion. We compared baseline parameters and outcome rates between groups, and performed multivariate analysis to assess the adjusted association of months to SC1 with RRA.

Results

We analyzed 516 lesions that underwent index pEMR resection and subsequent SC1. Baseline parameters and recurrence rates are presented in Table 1. The early SC1 group (n=371) underwent SC1 at a mean of 5.1 months versus a mean of 11.1 months in the late SC1 group (p<0.01; Table 1). Polyp size in the early SC1 group was significantly larger than that in the late SC1 group (mean size 35.9 mm [SD 13.9] vs. 32.1 mm [SD 12.4], p<0.01; Table 1). The distribution of lesion location, granularity differed between the groups (Table 1). However, there were no significant differences in lesion Paris classification or rates of high grade dysplasia (Table 1).
We found no statistically significant difference in the rate of recurrence at SC1 between the two groups (6.3% in the standard group versus 4.8% in the delayed group, p=0.64). Additionally, a sub-analysis comparing the early SC1 group to patients with very late SC1 (>12 months – mean time to SC1 17.9 (SD [5.4] months) and did not reveal significant difference in recurrence at SC1 (6.2% in the early SC1 vs 6.3% in the very late group, p=1).
Multivariate analysis, adjusted for lesion size, location, and high-grade dysplasia, showed that time to SC1 was not significantly associated with RRA (odds ratio 1.05, 95% confidence interval 0.98-1.13).

TABLE 1. Comparison of baseline variables and outcome between the early and late SC1.

Conclusion

Late SC1 is not associated with an increased RRA. Hence, we suggest that high-quality pEMR with margin ablation may alleviate the need for early SC1, thereby reducing healthcare and patient burdens. Further interventional studies are required.

References

[1] Ferlitsch M, Moss A, Hassan C, et al. Colorectal polypectomy and endoscopic mucosal resection (EMR): European Society of Gastrointestinal Endoscopy (ESGE) Clinical Guideline. Endoscopy 2017; 49: 270–297. doi:10.1055/S-0043-102569/ID/JR15335-1/BIB
[2] Shaukat A, Kaltenbach T, Dominitz JA, et al. Endoscopic Recognition and Management Strategies for Malignant Colorectal Polyps: Recommendations of the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology 2020; 159: 1916-1934.e2. doi:10.1053/j.gastro.2020.08.050
[3] Belderbos TDG, Leenders M, Moons LMG, et al. Local recurrence after endoscopic mucosal resection of nonpedunculated colorectal lesions: Systematic review and meta-analysis. Endoscopy 2014; 46: 388–400. doi:10.1055/S-0034-1364970/ID/JR910-7/BIB
[4] Klein A, Tate DJ, Jayasekeran V, et al. Thermal Ablation of Mucosal Defect Margins Reduces Adenoma Recurrence After Colonic Endoscopic Mucosal Resection. Gastroenterology 2019; 156: 604-613.e3. doi:10.1053/j.gastro.2018.10.003

Disclosure

The authors report no conflict of interests

Introduction

In addition to colonoscopy and histology, endoscopic ultrasound (EUS) plays a pivotal role in assessing rectal cancer (T-staging). As new therapeutic options emerge, exact imaging of the tumor is essential for the primary diagnosis and the evaluation of therapeutic response. In this regard, optical coherence tomography (OCT) offers a superior axial and lateral resolution compared to conventional rectal EUS and may contribute to individualized therapeutic strategies.

Aims & Methods

Our study aimed to evaluate the imaging quality of our further refined OCT-rectoscope prototype, which integrates an extended range additional to the optimized standard mode.
We integrated a double ferrule design with a fiber optical switch into a MHz-OCT rectoscope.
The performance of this adjustable OCT-rectoscope was assessed in two human colons, post-mortem and in situ. The body donors were preserved using an ethanol-glycerol-lysoformin-based technique resulting in true-to-life tissue consistency.

Results

The extended range mode adjusted the focus depth and imaging range and ensured imaging quality despite varying colon diameters or altered total wall thickness. The optimized standard mode gave a detailed resolution of the different rectal wall layers. Compared to the former prototype MHz-OCT rectoscope and rectal EUS, the images stood out: The mucosa appeared as a broad pale gray band, exactly circumscribed by the lamina muscularis mucosae. The submucosa was visualized as an inhomogeneous, light gray broad area. Furthermore, the muscularis propria comprising the circular and longitudinal muscle layer manifested as two homogeneous dark gray bands. The serosa was displayed as a bright band.

Conclusion

The new dual-mode MHz-OCT design allows a fast change between the extended range and the optimized standard mode. The imaging quality in both modes was exceptional compared to the state of the art EUS, with clear delineation of the different rectal wall layers, providing ideal conditions for accurate staging of rectal cancer. Further imaging studies are warranted to evaluate this dual-mode MHz-OCT rectoscope in human colons in vivo. In the future, this technique could serve additionally in indications like inflammatory bowel disease to quantify inflammation more precisely. Moreover, it could be integrated into a colonoscope design to evaluate the whole colon.

References

B. Schulte*, M. Göb* et al., High-resolution rectoscopy using MHz optical coherence tomography: a step towards real time 3D endoscopy. Scientific Reports, 02/2024
AP. Singh et al., Virtual Hall sensor triggered multi-MHz endoscopic OCT imaging for stable real-time visualization. Opt express, 02/2024