Cold Versus Hot Snare Endoscopic Resection of Large Nonpedunculated Colorectal Polyps: Randomized Controlled German CHRONICLE Trial.

BACKGROUND & AIMS: Endoscopic mucosal resection (EMR) is standard therapy for nonpedunculated colorectal polyps ≥20 mm. It has been suggested recently that polyp resection without current (cold resection) may be superior to the standard technique using cutting/coagulation current (hot resection) by reducing adverse events (AEs), but evidence from a randomized trial is missing. METHODS: In this randomized controlled multicentric trial involving 19 centers, nonpedunculated colorectal polyps ≥20 mm were randomly assigned to cold or hot EMR. The primary outcome was major AE (eg, perforation or postendoscopic bleeding). Among secondary outcomes, major AE subcategories, postpolypectomy syndrome, and residual adenoma were most relevant. RESULTS: Between 2021 and 2023, there were 396 polyps in 363 patients (48.2% were female) enrolled for the intention-to-treat analysis. Major AEs occurred in 1.0% of the cold group and in 7.9% of the hot group (P = .001; odds ratio [OR], 0.12; 95% CI, 0.03-0.54). Rates for perforation and postendoscopic bleeding were significantly lower in the cold group, with 0% vs 3.9% (P = .007) and 1.0% vs 4.4% (P = .040). Postpolypectomy syndrome occurred with similar frequency (3.1% vs 4.4%; P = .490). After cold resection, residual adenoma was found more frequently, with 23.7% vs 13.8% (P = .020; OR, 1.94; 95% CI, 1.12-3.38). In multivariable analysis, lesion diameter of ≥4 cm was an independent predictor both for major AEs (OR, 3.37) and residual adenoma (OR, 2.47) and high-grade dysplasia/cancer for residual adenoma (OR, 2.92). CONCLUSIONS: Cold resection of large, nonpedunculated colorectal polyps appears to be considerably safer than hot EMR; however, at the cost of a higher residual adenoma rate. Further studies have to confirm to what extent polyp size and histology can determine an individualized approach. German Clinical Trials Registry (Deutsches Register Klinischer Studien), Number DRKS00025170.

Endoscopic Submucosal Dissection for Early Esophageal Adenocarcinoma: Low Rates of Metastases in Mucosal Cancers with Poor Differentiation.

BACKGROUND AND AIMS: Endoscopic resection (ER) is accepted as standard treatment for intramucosal esophageal adenocarcinoma (EAC) with well or moderate differentiation. Poor differentiation (PD) is judged as a risk factor for lymph node metastasis (LNM) and surgery is recommended. However, the evidence for this recommendation is weak. Study aim was to analyze the clinical course of patients after ER of EAC with PD. PATIENTS AND METHODS: Patients undergoing endoscopic submucosal dissection for EAC were included from 16 German centers. Inclusion criteria were PD in the resection specimen, R0 resection and endoscopic follow-up. Primary outcome was the metastasis rate during follow-up. Analysis was performed retrospectively in a prospectively collected database. RESULTS: 25 patients with PD as single risk factor (group A) and 15 patients with PD and additional risk factors (submucosal invasion and/or lymphovascular invasion) were included. The metastasis rate was was 1/25 (4.0%; 95%CI 0.4-17.2) in group A and 3/15 (20.0%; 95%CI 6.0-44.4%) in group B, respectively (p=0.293). The rate of EAC-associated deaths was 1/25 (4%; 95%CI 0.4-17.2%) versus 3/15 (20%; 95%CI 6.0-44.4%) in group B (p=0.293) while the overall death rate was 7/25 (28.0%; 95%CI 13.5-47.3%) versus 3/15 (20%; 95%CI 6.0-44.4%) (p=0.715). Median follow-up was 30 months (IQR 15-53). CONCLUSIONS: During long-term follow-up the risk of metastasis is low after ER of mucosal EAC with PD as single risk factor. A conservative approach seems justified in this small patient group. However, the treatment strategy has to be determined on an individualized basis until further prospective data are available.

Characteristics and endoscopic treatment of interventional and non-interventional iatrogenic colorectal perforations in centers with high endoscopic expertise: a retrospective multicenter study.

BACKGROUND: Iatrogenic colorectal perforation is a rare event with a relevant mortality and the need for surgical therapy in around ¾ of cases. METHODS: In this retrospective multicentric cohort study iatrogenic colorectal perforations from 2004 to 2021 were analyzed. Primary outcome parameters were incidence and clinical success of 1st line endoscopic treatment. Comparative analysis of interventional and non-interventional perforations was performed and predictors for clinical success of endoscopic therapy were identified. RESULTS: From 103,570 colonoscopies 213 (0.2%) iatrogenic perforations were identified. 68.4% were interventional (80 during polypectomy/EMR, 54 during ESD and 11 for other reasons) and 31.6% non-interventional perforations (39 by the tip, 19 by the shaft, 7 by inversion, two by biopsy and one by distension). Incidence of 1st line endoscopic therapy was 61.0% and clinical success 81.5%. Other non-surgical therapies were conducted in 8.9% with clinical success in 94.7% of cases. In interventional perforations both incidence and clinical success of 1st line endoscopic therapy were significantly higher compared to non-interventional perforations [71.7% vs. 38.2% (p < 0.01) resp. 86.5% vs. 61.5% (p < 0.01)]. Mortality was 2.3% and significantly lower in the group of interventional perforations (0.7% vs. 5.9%, p = 0.037). Multivariable analysis revealed perforation size < 5 mm as only independent predictor for clinical success of 1st line endoscopic treatment [OR 14.85 (1.57-140.69), p = 0.019]. CONCLUSIONS: Endoscopic therapy is treatment of choice in the majority of iatrogenic colorectal perforations. In case of interventional perforations it is highly effective but only a minority of non-interventional perforations are good candidates for endoscopic treatment.

GPR18 Inhibiting Amauromine and the Novel Triterpene Glycoside Auxarthonoside from the Sponge-Derived Fungus Auxarthron reticulatum.

The marine sponge-derived fungus Auxarthron reticulatum produces the cannabinoid receptor antagonist amauromine (1). Recultivation of the fungus to obtain further amounts for more detailed pharmacological evaluation of 1 additionally yielded the novel triterpene glycoside auxarthonoside (2), bearing, in nature, a rather rare sugar moiety, i.e., N-acetyl-6-methoxy-glucosamine. Amauromine (1), which inhibited cannabinoid CB1 receptors (Ki 0.178 µM) also showed antagonistic activity at the cannabinoid-like orphan receptor GPR18 (IC50 3.74 µM). The diketopiperazine 1 may thus serve as a lead structure for the development of more potent and selective GPR18 antagonists, which are required to study the orphan receptor's potential as a new drug target. Despite the execution of many biological assays, to date, no bioactivity could be found for auxarthonoside (2).

Indoloditerpenes from a marine-derived fungal strain of Dichotomomyces cejpii with antagonistic activity at GPR18 and cannabinoid receptors.

A marine-derived strain of Dichotomomyces cejpii produces the new compounds emindole SB beta-mannoside (1) and 27-O-methylasporyzin C (2), as well as the known indoloditerpenes JBIR-03 (3) and emindole SB (4). Indole derivative 1 was found to be a CB2 antagonist, while 2 was identified as the first selective GPR18 antagonist with an indole structure. Compound 4 was found to be a nonselective CB1/CB2 antagonist. The new natural indole derivatives may serve as lead structures for the development of GPR18- and CB receptor-blocking drugs.

[Endoscopic strategies in minimal invasive therapy]. / Endoskopische Strategien zur minimal-invasiven Therapie.

Due to higher detection rates of early gastrointestinal neoplasia endoscopic resection of early GI cancers or precancerous lesions is increasing. Endoscopic piece-meal resection (EMR) remains the standard technique for the endoscopic resection of large sessile colorectal adenomas. Cap-assisted EMR techniques show excellent long-term results in the endoscopic therapy of neoplastic Barrett's esophagus. For the endoscopic resection of early gastrointestinal cancers of more than 2 cm endoscopic submucosal dissection (ESD) is the method of choice. The value of endoscopic full thickness resection in the therapy of GI tumors remains to be seen.

The natural product magnolol as a lead structure for the development of potent cannabinoid receptor agonists.

Magnolol (4-allyl-2-(5-allyl-2-hydroxyphenyl)phenol), the main bioactive constituent of the medicinal plant Magnolia officinalis, and its main metabolite tetrahydromagnolol were recently found to activate cannabinoid (CB) receptors. We now investigated the structure-activity relationships of (tetrahydro)magnolol analogs with variations of the alkyl chains and the phenolic groups and could considerably improve potency. Among the most potent compounds were the dual CB1/CB2 full agonist 2-(2-methoxy-5-propyl-phenyl)-4-hexylphenol (61a, K(i) CB1:0.00957 µM; K(i) CB2:0.0238 µM), and the CB2-selective partial agonist 2-(2-hydroxy-5-propylphenyl)-4-pentylphenol (60, K(i) CB1:0.362 µM; K(i ) CB2:0.0371 µM), which showed high selectivity versus GPR18 and GPR55. Compound 61b, an isomer of 61a, was the most potent GPR55 antagonist with an IC50 value of 3.25 µM but was non-selective. The relatively simple structures, which possess no stereocenters, are easily accessible in a four- to five-step synthetic procedure from common starting materials. The central reaction step is the well-elaborated Suzuki-Miyaura cross-coupling reaction, which is suitable for a combinatorial chemistry approach. The scaffold is versatile and may be fine-tuned to obtain a broad range of receptor affinities, selectivities and efficacies.

Antagonists for the orphan G-protein-coupled receptor GPR55 based on a coumarin scaffold.

The orphan G-protein-coupled receptor GPR55, which is activated by 1-lysophosphatidylinositol and interacts with cannabinoid (CB) receptor ligands, has been proposed as a new potential drug target for the treatment of diabetes, Parkinson's disease, neuropathic pain, and cancer. We applied ß-arrestin assays to identify 3-substituted coumarins as a novel class of antagonists and performed an extensive structure-activity relationship study for GPR55. Selectivity versus the related receptors CB1, CB2, and GPR18 was assessed. Among the 7-unsubstituted coumarins selective, competitive GPR55 antagonists were identified, such as 3-(2-hydroxybenzyl)-5-isopropyl-8-methyl-2H-chromen-2-one (12, PSB-SB-489, IC50 = 1.77 µM, pA2 = 0.547 µM). Derivatives with long alkyl chains in position 7 were potent, possibly allosteric GPR55 antagonists which showed ancillary CB receptor affinity. 7-(1,1-Dimethyloctyl)-5-hydroxy-3-(2-hydroxybenzyl)-2H-chromen-2-one (69, PSB-SB-487, IC50 = 0.113 µM, KB = 0.561 µM) and 7-(1,1-dimethylheptyl)-5-hydroxy-3-(2-hydroxybenzyl)-2H-chromen-2-one (67, PSB-SB-1203, IC50 = 0.261 µM) were the most potent GPR55 antagonists of the present series.

Magnolia Extract, Magnolol, and Metabolites: Activation of Cannabinoid CB2 Receptors and Blockade of the Related GPR55.

The bark of Magnolia officinalis is used in Asian traditional medicine for the treatment of anxiety, sleeping disorders, and allergic diseases. We found that the extract and its main bioactive constituents, magnolol and honokiol, can activate cannabinoid (CB) receptors. In cAMP accumulation studies, magnolol behaved as a partial agonist (EC50 = 3.28 µM) with selectivity for the CB2 subtype, while honokiol was less potent showing full agonistic activity at CB1 and antagonistic properties at CB2. We subsequently synthesized the major metabolites of magnolol and found that tetrahydromagnolol (7) was 19-fold more potent than magnolol (EC50 CB2 = 0.170 µM) exhibiting high selectivity versus CB1. Additionally, 7 behaved as an antagonist at GPR55, a CB-related orphan receptor (K B = 13.3 µM, ß-arrestin translocation assay). Magnolol and its metabolites may contribute to the biological activities of Magnolia extract via the observed mechanisms of action. Furthermore, the biphenylic compound magnolol provides a simple novel lead structure for the development of agonists for CB receptors and antagonists for the related GPR55.

7-Alkyl-3-benzylcoumarins: a versatile scaffold for the development of potent and selective cannabinoid receptor agonists and antagonists.

A series of 7-alkyl-3-benzylcoumarins was designed, synthesized, and tested at cannabinoid CB(1) and CB(2) receptors in radioligand binding and cAMP accumulation studies. 7-Alkyl-3-benzylcoumarins were found to constitute a versatile scaffold for obtaining potent CB receptor ligands with high potency at either CB(1) or CB(2) and a broad spectrum of efficacies. Fine-tuning of compound properties was achieved by small modifications of the substitution pattern. The most potent compounds of the present series include 5-methoxy-3-(2-methylbenzyl)-7-pentyl-2H-chromen-2-one (19a, PSB-SB-1201), a selective CB(1)antagonist (K(i) CB(1) 0.022 µM), 5-methoxy-3-(2-methoxybenzyl)-7-pentyl-2H-chromen-2-one (21a, PSB-SB-1202), a dual CB(1)/CB(2)agonist (CB(1)K(i) 0.032 µM, EC(50) 0.056 µM; CB(2)K(i) 0.049 µM, EC(50) 0.014 µM), 5-hydroxy-3-(2-hydroxybenzyl)-7-(2-methyloct-2-yl)-2H-chromen-2-one (25b, PSB-SB-1203), a dual CB(1)/CB(2) ligand that blocks CB(1) but activates CB(2) receptors (CB(1)K(i) 0.244 µM; CB(2)K(i) 0.210 µM, EC(50) 0.054 µM), and 7-(1-butylcyclopentyl)-5-hydroxy-3-(2-hydroxybenzyl)-2H-chromen-2-one (27b, PSB-SB-1204), a selective CB(2) receptor agonist (CB(1)K(i) 1.59 µM; CB(2)K(i) 0.068 µM, EC(50) 0.048 µM).

Identification of a Potent and Selective Cannabinoid CB1 Receptor Antagonist from Auxarthron reticulatum.

The fungus Auxarthron reticulatum derived from the marine sponge Ircinia variabilis produced the diketopiperazine alkaloid amauromine (1) and the quinolinone methyl-penicinoline (2). Compound 2 is identical to the reported methyl-marinamide, whose structure is herewith revised. In radioligand binding studies at human cannabinoid CB1 and CB2 receptors recombinantly expressed in Chinese hamster ovary (CHO) cells, amauromine (1) was found to exhibit high affinity and selectivity for the CB1 receptor (K i = 178 nM). The compound was shown to be a neutral CB1 antagonist with a K b value of 66.6 nM determined in cAMP assays. Compound 2 exhibited only weak or no effects at CB receptors. To the best of our knowledge, compound 1 is the first fungal natural product that shows affinity for cannabinoid CB1 receptors. Because of its high antagonistic potency and selectivity, it may have potential for use as a drug and/or serve as a lead structure for drug development.