Rituximab is a safe and effective alternative treatment for patients with autoimmune hepatitis: Results from the ColHai registry.

BACKGROUND AND AIMS: Small series suggest that rituximab could be effective as treatment for autoimmune hepatitis (AIH), although data are scarce. We aimed to evaluate the efficacy and safety of rituximab in different cohorts of patients with AIH. METHODS: Multicentre retrospective analysis of the 35 patients with AIH and its variant forms treated with rituximab and included in the ColHai registry between 2015 and 2023. RESULTS: Most patients were female (83%), 10 (29%) had cirrhosis and four (11.4%) variant forms of AIH. Indication for rituximab were as follows: 14(40%) refractory AIH, 19(54%) concomitant autoimmune or haematological disorder, 2(6%) intolerance to prior treatments. In three (9%) subjects with a concomitant disorder, rituximab was the first therapy for AIH. Overall, 31 (89%) patients achieved or maintained complete biochemical response (CBR), including the three in first-line therapy. No difference in CBR was observed according to rituximab indication (refractory AIH 86% vs. concomitant disorders 90%, p = .824) or cirrhosis (80% vs. 92%, p = .319). Rituximab was associated with a significant reduction in corticosteroids (median dose: prior 20 vs. post 5 mg, p < .001) and the discontinuation of ≥1 immunosuppressant in 47% of patients. Flare-free rate at 1st, 2nd and 3rd year was 86%, 73% and 62% respectively. Flares were not associated with the development of liver failure and were successfully managed with repeated doses of rituximab and/or increased corticosteroids. Three (9%) patients experienced infusion-related adverse events (1 anaphylaxis and 2 flu-like symptoms) and five (14%) infections. CONCLUSION: Rituximab is safe and effective in patients with refractory AIH and those treated due to concomitant autoimmune or haematological disorders.

On-Demand Activation of Transesterification by Chemical Amplification in Dynamic Thiol-Ene Photopolymers.

Chemical amplification is a well-established concept in photoresist technology, wherein one photochemical event leads to a cascade of follow-up reactions that facilitate a controlled change in the solubility of a polymer. Herein, we transfer this concept to dynamic polymer networks to liberate both catalyst and functional groups required for bond exchange reactions under UV irradiation. For this, we exploit a photochemically generated acid to catalyse a deprotection reaction of an acid-labile tert-butoxycarbonyl group, which is employed to mask the hydroxy groups of a vinyl monomer. At the same time, the released acid serves as a catalyst for thermo-activated transesterifications between the deprotected hydroxy and ester moieties. Introduced in an orthogonally cured (450 nm) thiol-click photopolymer, this approach allows for a spatio-temporally controlled activation of bond exchange reactions, which is crucial in light of the creep resistance versus reflow ability trade-off of dynamic polymer networks.

Exploring Aromatic S-Thioformates as Photoinitiators.

Thiyl radicals were generated from aromatic S-thioformates by photolysis. The corresponding photo-initiated decarbonylation allows initiating polymerization reactions in both acrylate- and thiol-acrylate-based resin systems. Compared to aromatic thiols, the introduction of the photolabile formyl group prevents undesired reactions with acrylate monomers allowing photoinitiators (PIs) with constant reactivity over storage. To demonstrate the potential of S-thioformates as PIs, the bifunctional molecule S,S'-(thiobis(4,1-phenylene))dimethanethioate (2b) was synthesized, providing reactivity under visible light excitation. Consequently, acrylate-based formulations could successfully be processed by digital light processing (DLP)-based stereolithography at 405 nm in high resolution.

Blocked Phosphates as Photolatent Catalysts for Dynamic Photopolymer Networks.

While latent catalysts are a well-established strategy for initiating and controlling the rate of polymerization reactions, their use in dynamic polymer networks is still in its infancy. The ideal latent catalyst should be thermally stable and release a highly active species in response to an external trigger. Here, we have synthesized a temperature resistant (>200 °C) organic phosphate with a photolabile o-nitrobenzyl protecting group that can be cleaved by UV light. Introduced in a visible light curable thiol-click photopolymer, the sequence-dependent λ-orthogonality of the curing and cleavage enables an efficient network formation at 451 nm, without premature release of the catalyst. Once cured, irradiation at 372 nm spatiotemporally activates the phosphate, which catalyzes transesterifications at elevated temperature. The formed catalyst has no effect on the thermal stability of the polymeric network and allows the activation of bond exchange reactions in selected domains of printed 3D objects.

Obeticholic Acid and Fibrates in Primary Biliary Cholangitis: Comparative Effects in a Multicentric Observational Study.

INTRODUCTION: Obeticholic acid (OCA) and fibrates therapy results in biochemical improvement in placebo-controlled trials in patients with primary biliary cholangitis and insufficient response to ursodeoxycholic acid. There is scarce information outside of clinical trials. Therefore, we have assessed the effectiveness and adverse events of these treatments. METHODS: Data from patients included in the ColHai registry treated with OCA, fibrates, or both were recorded during a year, as well as adverse events and treatment discontinuation. RESULTS: Eighty-six patients were treated with OCA, 250 with fibrates (81% bezafibrate; 19% fenofibrate), and 15 with OCA plus fibrates. OCA group had baseline significantly higher alkaline phosphatase (ALP) (P = 0.01) and lower platelets (P = 0.03) than fibrates. Both treatments significantly decreased ALP, gamma-glutamyl transferase (GGT), and transaminases and improved Globe score. Albumin and immunoglobulin type M improved in the fibrates group. ALP decrease was higher under fibrates, whereas alanine aminotransferase decline was higher under OCA. Although baseline transaminases and GGT were higher in patients with OCA plus fibrates, significant ALP, GGT, alanine aminotransferase, and Globe score improvement were observed during triple therapy. Adverse events were reported in 14.7% of patients (21.3% OCA; 17.6% fenofibrate; 10.7% bezafibrate), mainly pruritus (10.1% with OCA). Discontinuation was more frequent in fenofibrate treatment mainly because of intolerance or adverse events. DISCUSSION: Second-line therapy with OCA or fibrates improves hepatic biochemistry and the GLOBE score in primary biliary cholangitis patients with suboptimal response to ursodeoxycholic acid. Simultaneous treatment with OCA and fibrates improved ALP as well.

Recent Advances in Functional Polymers Containing Coumarin Chromophores.

Natural and synthetic coumarin derivatives have gained increased attention in the design of functional polymers and polymer networks due to their unique optical, biological, and photochemical properties. This review provides a comprehensive overview over recent developments in macromolecular architecture and mainly covers examples from the literature published from 2004 to 2020. Along with a discussion on coumarin and its photochemical properties, we focus on polymers containing coumarin as a nonreactive moiety as well as polymer systems exploiting the dimerization and/or reversible nature of the [2πs + 2πs] cycloaddition reaction. Coumarin moieties undergo a reversible [2πs + 2πs] cycloaddition reaction upon irradiation with specific wavelengths in the UV region, which is applied to impart intrinsic healability, shape-memory, and reversible properties into polymers. In addition, coumarin chromophores are able to dimerize under the exposure to direct sunlight, which is a promising route for the synthesis and cross-linking of polymer systems under "green" and environment-friendly conditions. Along with the chemistry and design of coumarin functional polymers, we highlight various future application fields of coumarin containing polymers involving tissue engineering, drug delivery systems, soft robotics, or 4D printing applications.

Lipid-independent control of endothelial and neuronal TRPC3 channels by light.

Lipid-gated TRPC channels are highly expressed in cardiovascular and neuronal tissues. Exerting precise pharmacological control over their activity in native cells is expected to serve as a basis for the development of novel therapies. Here we report on a new photopharmacological tool that enables manipulation of TRPC3 channels by light, in a manner independent of lipid metabolism and with higher temporal precision than lipid photopharmacology. Using the azobenzene photoswitch moiety, we modified GSK1702934A to generate light-controlled TRPC agonists. We obtained one light-sensitive molecule (OptoBI-1) that allows us to exert efficient, light-mediated control over TRPC3 activity and the associated cellular Ca2+ signaling. OptoBI-1 enabled high-precision, temporal control of TRPC3-linked cell functions such as neuronal firing and endothelial Ca2+ transients. With these findings, we introduce a novel photopharmacological strategy to control native TRPC conductances.

A single point mutation in the TRPC3 lipid-recognition window generates supersensitivity to benzimidazole channel activators.

Mutation of a single residue within the recently identified lipid (diacylglycerol) recognition window of TRPC3 (G652A) was found to abolish channel activation via endogenous lipid mediators while retaining sensitivity to the non-lipid activator GSK1702934A (abb. GSK). The mechanism of this change in chemical sensing by TRPC3 was analysed by whole-cell and single channel electrophysiology as well as Ca2+ imaging. Currents initiated by GSK or the structural (benzimidazole) analog BI-2 were significantly larger in cells expressing the G652A mutant as compared to wild type (WT) channels. Whole cell patch-clamp experiments revealed that enhanced sensitivity to benzimidazoles was not due to augmented potency but reflected enhanced efficacy of benzimidazoles. Single channel analysis demonstrated that neither unitary conductance nor I-V characteristics were altered by the G652A mutation, precluding altered pore architecture as the basis of enhanced efficacy. These experiments uncovered a distinct gating pattern of BI-2-activated G652A mutant channels, featuring a unique, long-lived open state. Moreover, G652A mutant channels lacked PLC/diacylglycerol mediated cross-desensitization for GSK activation as typically observed for TRPC3. Lack of desensitization in G652A channels enabled large GSK/BI-2-induced Ca2+ signals in conditions that fully desensitized TRPC3 WT channels. We demonstrate that the lipid-recognition window of TRPC3 determines both sensitivity to lipid mediators and chemical gating by benzimidazoles. TRPC3 mutations within this lipid interaction site are suggested as a basis for chemogenetic targeting of TRPC3-signaling.

Efficacy and safety of anticoagulation in non-malignant portal vein thrombosis in patients with liver cirrhosis.

BACKGROUND AND AIM: Treatment for portal vein thrombosis (PVT) is not well established. Nevertheless, anticoagulation therapy can seemingly be used as first-line therapy. However, there are limited data on the role of this treatment in patients with PVT and cirrhosis. We sought to assess the safety and efficacy of anticoagulation therapy in a series of patients with non-malignant PVT and liver cirrhosis. METHODS: We analyzed the data of 32 patients with cirrhosis and PVT between March 2009 and September 2015. All patients received anticoagulation treatment. PVT was diagnosed within the context of biannual hepatocellular carcinoma screening in these patients. RESULTS: Recanalisation was achieved in 23 patients: complete in 17 patients (53.1%) and partial in 6 patients (18.7%). The median time for achieving a complete response was 7 months (95% CI: 6-8). We did not discover any risk factors associated with repermeation (partial or complete). None of the patients presented with thrombosis progression while receiving anticoagulation. Nine patients who achieved complete recanalisation and stopped anticoagulation therapy suffered rethrombosis (52%). There were no differences between the patients who achieved complete or partial recanalisation (35%) and those who did not (33%) in relation to the onset of hepatic events during follow-up. Three patients (9%) presented with bleeding complications: two variceal bleeding episodes and one brain hemorrhage. CONCLUSIONS: In cirrhotic patients with non-malignant PVT, anticoagulation therapy led to partial or complete recanalisation in 70% of patients, with a broad safety profile. Due to the existing rethrombosis rate, long-term anticoagulation should be considered.

Homoarsenocholine - A novel arsenic compound detected for the first time in nature.

The arsenic speciation was determined in macrofungi of the Ramaria genus with HPLC coupled to inductively coupled plasma mass spectrometry. Besides arsenic species that are already known for macrofungi, like arsenobetaine or arsenocholine, two compounds that were only known from marine samples so far (trimethylarsoniopropanate and dimethylarsinoylacetate) were found for the first time in a terrestrial sample. An unknown arsenical was isolated and identified as homoarsenocholine. This could be a key intermediate for further elucidation of the biotransformation mechanisms of arsenic.

An optically controlled probe identifies lipid-gating fenestrations within the TRPC3 channel.

Transient receptor potential canonical (TRPC) channels TRPC3, TRPC6 and TRPC7 are able to sense the lipid messenger diacylglycerol (DAG). The DAG-sensing and lipid-gating processes in these ion channels are still unknown. To gain insights into the lipid-sensing principle, we generated a DAG photoswitch, OptoDArG, that enabled efficient control of TRPC3 by light. A structure-guided mutagenesis screen of the TRPC3 pore domain unveiled a single glycine residue behind the selectivity filter (G652) that is exposed to lipid through a subunit-joining fenestration. Exchange of G652 with larger residues altered the ability of TRPC3 to discriminate between different DAG molecules. Light-controlled activation-deactivation cycling of TRPC3 channels by an OptoDArG-mediated optical 'lipid clamp' identified pore domain fenestrations as pivotal elements of the channel´s lipid-sensing machinery. We provide evidence for a novel concept of lipid sensing by TRPC channels based on a lateral fenestration in the pore domain that accommodates lipid mediators to control gating.

Intensified Microwave-Assisted N-Acylation Procedure - Synthesis and Activity Evaluation of TRPC3 Channel Agonists with a 1,3-Dihydro-2H-benzo[d]imidazol-2-one Core.

Upon controlled microwave heating and using cyanuric chloride as a coupling reagent, an efficient amidation procedure for the synthesis of 1,3-dihydro-2H-benzo[d]imidazol-2-one-based agonists of TRPC3/6 ion channels has been developed. Compared to the few conventional protocols, a drastic reduction in processing time from ca. 2 days down to 10 minutes was achieved accompanied by significantly improved product yields. The robustness of the method was confirmed by 18 additional examples including aromatic, aliphatic, and heterocyclic amines and acids. The obtained agonists were screened for biological activity at 1 µM concentration and few structure-activity relations have been established.

Optopharmacological control of TRPC channels by coumarin-caged lipids is associated with a phototoxic membrane effect.

Photouncaging of second messengers has been successfully employed to gain mechanistic insight of cellular signaling pathways. One of the most enigmatic processes of ion channel regulation is lipid recognition and lipid-gating of TRPC channels, which represents pivotal mechanisms of cellular Ca(2+) homeostasis. Recently, optopharmacological tools including caged lipid mediators became available, enabling an unprecedented level of temporal and spatial control of the activating lipid species within a cellular environment. Here we tested a commonly used caged ligand approach for suitability to investigate TRPC signaling at the level of membrane conductance and cellular Ca(2+) handling. We report a specific photouncaging artifact that is triggered by the cage structure coumarin at UV illumination. Electrophysiological characterization identified a light-dependent membrane effect of coumarin. UV light (340 nm) as used for photouncaging, initiated a membrane conductance specifically in the presence of coumarin as low as 30 µmol L(-1) concentrations. This conductance masked the TRPC3 conductance evoked by photouncaging, while TRPC-mediated cellular Ca(2+) responses were largely preserved. The observed light-induced membrane effects of the released caging moiety may well interfere with certain cellular functions, and prompt caution in using coumarin-caged second messengers in cellular studies.

[Study of predictive factors of severe digestive lesions due to caustics ingestion]. / Estudio de los factores predictivos de lesiones digestivas graves tras la ingestión de cáusticos.

OBJECTIVE: Our purpose was to analyze the predictive factors of severe upper gastrointestinal injury by caustic substances in adult patients. PATIENTS AND METHOD: Retrospective study between February 1995 and February 2001 of adult patients who underwent an urgent upper endoscopy due to caustic ingestion. Endoscopic caustic ingestion criteria by Zargar et al were used to determine the degree of injury. We performed a univariate study of factors associated with sever digestive injury and, lately, a logistic regression analysis of predictive factors. Sensitivity, specificity, positive and negative predictive values of these factors were calculated. RESULTS: One hundred and fifty nine patients were included in the study, whose mean age was 48.9 (20.1) years and 49.7% were men. The more frequent caustic ingested was lye (47.8%). A severe caustic injury was found in urgent upper endoscopy in 18.4% of patients, which was located in esophagus in 14.6%, stomach in 8.2% and duodenum in 0.6% of cases. Male sex, voluntary ingestion, oropharingeal lesions, significant clinical symptoms and dishwasher and detergents ingestion were associated with severe upper gastrointestinal tract (GIT) injury. Voluntary ingestion, oropharingeal lesions and significant clinical symptoms at admission were independent predictive factors of severe GIT injury. The existence of one of these factors had an 89.7% of sensitivity while two or more displayed a specificity of 91%. CONCLUSIONS: Clinical and exploratory data may determine, before upper endoscopic procedure, the probability of severe GIT injury by caustic ingestion. Therefore, these data could play a significant role in the diagnostic, prognostic and therapeutic management of caustic ingestion.