A real-time deep learning-based system for colorectal polyp size estimation by white-light endoscopy: development and multicenter prospective validation.

BACKGROUND: The choice of polypectomy device and surveillance intervals for colorectal polyps are primarily decided by polyp size. We developed a deep learning-based system (ENDOANGEL-CPS) to estimate colorectal polyp size in real time. METHODS: ENDOANGEL-CPS calculates polyp size by estimating the distance from the endoscope lens to the polyp using the parameters of the lens. The depth estimator network was developed on 7297 images from five virtually produced colon videos and tested on 730 images from seven virtual colon videos. The performance of the system was first evaluated in nine videos of a simulated colon with polyps attached, then tested in 157 real-world prospective videos from three hospitals, with the outcomes compared with that of nine endoscopists over 69 videos. Inappropriate surveillance recommendations caused by incorrect estimation of polyp size were also analyzed. RESULTS: The relative error of depth estimation was 11.3% (SD 6.0%) in successive virtual colon images. The concordance correlation coefficients (CCCs) between system estimation and ground truth were 0.89 and 0.93 in images of a simulated colon and multicenter videos of 157 polyps. The mean CCC of ENDOANGEL-CPS surpassed all endoscopists (0.89 vs. 0.41 [SD 0.29]; P<0.001). The relative accuracy of ENDOANGEL-CPS was significantly higher than that of endoscopists (89.9% vs. 54.7%; P<0.001). Regarding inappropriate surveillance recommendations, the system's error rate is also lower than that of endoscopists (1.5% vs. 16.6%; P<0.001). CONCLUSIONS: ENDOANGEL-CPS could potentially improve the accuracy of colorectal polyp size measurements and size-based surveillance intervals.

Effect of artificial intelligence on novice-performed colonoscopy: a multicenter randomized controlled tandem study.

BACKGROUND AND AIMS: The efficacy and safety of colonoscopy performed by artificial intelligence (AI)-assisted novices remain unknown. The aim of this study was to compare the lesion detection capability of novices, AI-assisted novices, and experts. METHODS: This multicenter, randomized, noninferiority tandem study was conducted across 3 hospitals in China from May 1, 2022, to November 11, 2022. Eligible patients were randomized into 1 of 3 groups: the CN group (control novice group, withdrawal performed by a novice independently), the AN group (AI-assisted novice group, withdrawal performed by a novice with AI assistance), or the CE group (control expert group, withdrawal performed by an expert independently). Participants underwent a repeat colonoscopy conducted by an AI-assisted expert to evaluate the lesion miss rate and ensure lesion detection. The primary outcome was the adenoma miss rate (AMR). RESULTS: A total of 685 eligible patients were analyzed: 229 in the CN group, 227 in the AN group, and 229 in the CE group. Both AMR and polyp miss rate were lower in the AN group than in the CN group (18.82% vs 43.69% [P < .001] and 21.23% vs 35.38% [P < .001], respectively). The noninferiority margin was met between the AN and CE groups of both AMR and polyp miss rate (18.82% vs 26.97% [P = .202] and 21.23% vs 24.10% [P < .249]). CONCLUSIONS: AI-assisted colonoscopy lowered the AMR of novices, making them noninferior to experts. The withdrawal technique of new endoscopists can be enhanced by AI-assisted colonoscopy. (Clinical trial registration number: NCT05323279.).

The guanine nucleotide exchange factor Rin-like controls Tfh cell differentiation via CD28 signaling.

T follicular helper (Tfh) cells are essential for the development of germinal center B cells and high-affinity antibody-producing B cells in humans and mice. Here, we identify the guanine nucleotide exchange factor (GEF) Rin-like (Rinl) as a negative regulator of Tfh generation. Loss of Rinl leads to an increase of Tfh in aging, upon in vivo immunization and acute LCMV Armstrong infection in mice, and in human CD4+ T cell in vitro cultures. Mechanistically, adoptive transfer experiments using WT and Rinl-KO naïve CD4+ T cells unraveled T cell-intrinsic GEF-dependent functions of Rinl. Further, Rinl regulates CD28 internalization and signaling, thereby shaping CD4+ T cell activation and differentiation. Thus, our results identify the GEF Rinl as a negative regulator of global Tfh differentiation in an immunological context and species-independent manner, and furthermore, connect Rinl with CD28 internalization and signaling pathways in CD4+ T cells, demonstrating for the first time the importance of endocytic processes for Tfh differentiation.

MC1R Peptide Agonist Self-Assembles into a Hydrogel That Promotes Skin Pigmentation for Treating Vitiligo.

Vitiligo, a common skin disease that seriously affects 0.5-2.0% of the worldwide population, lacks approved therapeutics due to a wide range of adverse side effects. As a key regulator of skin pigmentation, MC1R may be an effective therapeutic target for vitiligo. Herein, we report an MC1R peptide agonist that directly self-assembles into nanofibrils that form a hydrogel matrix under normal physiological conditions. This hydrogel exhibits higher stability than free peptides, sustained release, rapid recovery from shear-thinning, and resistance to enzymatic proteolysis. Furthermore, this peptidal MC1R agonist upregulates tyrosinase, tyrosinase-related protein-1 (TYRP-1), and tyrosinase-related protein-2 (TYRP-2) to stimulate melanin synthesis. More importantly, MC1R agonist hydrogel promotes skin pigmentation in mice more potently than free MC1R agonist. This study supports the development of this MC1R agonist hydrogel as a promising pharmacological intervention for vitiligo.

Loss of bile salt export pump aggravates lipopolysaccharide-induced liver injury in mice due to impaired hepatic endotoxin clearance.

BACKGROUND AND AIMS: Lipopolysaccharide (LPS) clearance is delayed in cholestatic liver diseases. While compromised clearance by Kupffer cells (KCs) is involved, the role of LPS uptake into hepatocytes and canalicular excretion remains unclear. APPROACH AND RESULTS: Wild-type (WT) and bile salt export pump (Bsep) knockout (KO) mice were challenged i.p. with LPS. Liver injury was assessed by serum biochemistry, histology, molecular inflammation markers, and immune cell infiltration. LPS concentrations were determined in liver tissue and bile. Subcellular kinetics of fluorescently labeled LPS was visualized by intravital two-photon microscopy, and the findings in Bsep KO mice were compared to common bile duct-ligated (BDL) and multidrug resistance protein 2 (Mdr2) KO mice. Changes in gut microbiota composition were evaluated by 16S ribosomal RNA gene amplicon sequencing analysis. Bsep KO mice developed more pronounced LPS-induced liver injury and inflammatory signaling, with subsequently enhanced production of proinflammatory cytokines and aggravated hepatic immune cell infiltration. After LPS administration, its concentrations were higher in liver but lower in bile of Bsep KO compared to WT mice. Intravital imaging of LPS showed a delayed clearance from sinusoidal blood with a basolateral uptake block into hepatocytes and reduced canalicular secretion. Moreover, LPS uptake into KCs was reduced. Similar findings with respect to hepatic LPS clearance were obtained in BDL and Mdr2 KO mice. Pretreatment with the microtubule inhibitor colchicine inhibited biliary excretion of LPS in WT mice, indicating that LPS clearance is microtubule-dependent. Microbiota analysis showed no change of the gut microbiome between WT and Bsep KO mice at baseline but major changes upon LPS challenge in WT mice. CONCLUSIONS: Absence of Bsep and cholestasis in general impair LPS clearance by a basolateral uptake block into hepatocytes and consequently less secretion into canaliculi. Impaired LPS removal aggravates hepatic inflammation in cholestasis.

24-Norursodeoxycholic acid reshapes immunometabolism in CD8+ T cells and alleviates hepatic inflammation.

BACKGROUND & AIMS: 24-Norursodeoxycholic acid (NorUDCA) is a novel therapeutic bile acid used to treat immune-mediated cholestatic liver diseases, such as primary sclerosing cholangitis (PSC), where dysregulated T cells including CD8+ T cells contribute to hepatobiliary immunopathology. We hypothesized that NorUDCA may directly modulate CD8+ T cell function thus contributing to its therapeutic efficacy. METHODS: NorUDCA's immunomodulatory effects were first studied in Mdr2-/- mice, as a cholestatic model of PSC. To differentiate NorUDCA's immunomodulatory effects on CD8+ T cell function from its anticholestatic actions, we also used a non-cholestatic model of hepatic injury induced by an excessive CD8+ T cell immune response upon acute non-cytolytic lymphocytic choriomeningitis virus (LCMV) infection. Studies included molecular and biochemical approaches, flow cytometry and metabolic assays in murine CD8+ T cells in vitro. Mass spectrometry was used to identify potential CD8+ T cell targets modulated by NorUDCA. The signaling effects of NorUDCA observed in murine cells were validated in circulating T cells from patients with PSC. RESULTS: NorUDCA demonstrated immunomodulatory effects by reducing hepatic innate and adaptive immune cells, including CD8+ T cells in the Mdr2-/- model. In the non-cholestatic model of CD8+ T cell-driven immunopathology induced by acute LCMV infection, NorUDCA ameliorated hepatic injury and systemic inflammation. Mechanistically, NorUDCA demonstrated strong immunomodulatory efficacy in CD8+ T cells affecting lymphoblastogenesis, expansion, glycolysis and mTORC1 signaling. Mass spectrometry identified that NorUDCA regulates CD8+ T cells by targeting mTORC1. NorUDCA's impact on mTORC1 signaling was further confirmed in circulating PSC CD8+ T cells. CONCLUSIONS: NorUDCA has a direct modulatory impact on CD8+ T cells and attenuates excessive CD8+ T cell-driven hepatic immunopathology. These findings are relevant for treatment of immune-mediated liver diseases such as PSC. LAY SUMMARY: Elucidating the mechanisms by which 24-norursodeoxycholic acid (NorUDCA) works for the treatment of immune-mediated liver diseases, such as primary sclerosing cholangitis, is of considerable clinical interest. Herein, we uncovered an unrecognized property of NorUDCA in the immunometabolic regulation of CD8+ T cells, which has therapeutic relevance for immune-mediated liver diseases, including PSC.

The energy sensor AMPK orchestrates metabolic and translational adaptation in expanding T helper cells.

The importance of cellular metabolic adaptation in inducing robust T cell responses is well established. However, the mechanism by which T cells link information regarding nutrient supply to clonal expansion and effector function is still enigmatic. Herein, we report that the metabolic sensor adenosine monophosphate-activated protein kinase (AMPK) is a critical link between cellular energy demand and translational activity and, thus, orchestrates optimal expansion of T cells in vivo. AMPK deficiency did not affect T cell fate decision, activation, or T effector cell generation; however, the magnitude of T cell responses in murine in vivo models of T cell activation was markedly reduced. This impairment was global, as all T helper cell subsets were similarly sensitive to loss of AMPK which resulted in reduced T cell accumulation in peripheral organs and reduced disease severity in pathophysiologically as diverse models as T cell transfer colitis and allergic airway inflammation. T cell receptor repertoire analysis confirmed similar clonotype frequencies in different lymphoid organs, thereby supporting the concept of a quantitative impairment in clonal expansion rather than a skewed qualitative immune response. In line with these findings, in-depth metabolic analysis revealed a decrease in T cell oxidative metabolism, and gene set enrichment analysis indicated a major reduction in ribosomal biogenesis and mRNA translation in AMPK-deficient T cells. We, thus, provide evidence that through its interference with these delicate processes, AMPK orchestrates the quantitative, but not the qualitative, manifestation of primary T cell responses in vivo.

Histone deacetylase 1 controls CD4+ T cell trafficking in autoinflammatory diseases.

CD4+ T cell trafficking is a fundamental property of adaptive immunity. In this study, we uncover a novel role for histone deacetylase 1 (HDAC1) in controlling effector CD4+ T cell migration, thereby providing mechanistic insight into why a T cell-specific deletion of HDAC1 protects against experimental autoimmune encephalomyelitis (EAE). HDAC1-deficient CD4+ T cells downregulated genes associated with leukocyte extravasation. In vitro, HDAC1-deficient CD4+ T cells displayed aberrant morphology and migration on surfaces coated with integrin LFA-1 ligand ICAM-1 and showed an impaired ability to arrest on and to migrate across a monolayer of primary mouse brain microvascular endothelial cells under physiological flow. Moreover, HDAC1 deficiency reduced homing of CD4+ T cells into the intestinal epithelium and lamina propria preventing weight-loss, crypt damage and intestinal inflammation in adoptive CD4+ T cell transfer colitis. This correlated with reduced expression levels of LFA-1 integrin chains CD11a and CD18 as well as of selectin ligands CD43, CD44 and CD162 on transferred circulating HDAC1-deficient CD4+ T cells. Our data reveal that HDAC1 controls T cell-mediated autoimmunity via the regulation of CD4+ T cell trafficking into the CNS and intestinal tissues.

The Tyrosine Kinase Tec Regulates Effector Th17 Differentiation, Pathogenicity, and Plasticity in T-Cell-Driven Intestinal Inflammation.

T helper (Th) 17 cells are not only key in controlling infections mediated by extracellular bacteria and fungi but are also triggering autoimmune responses. Th17 cells comprise heterogeneous subsets, some with pathogenic functions. They can cease to secrete their hallmark cytokine IL-17A and even convert to other T helper lineages, a process known as transdifferentiation relying on plasticity. Both pathogenicity and plasticity are tightly linked to IL-23 signaling. Here, we show that the protein tyrosine kinase Tec is highly induced in Th17 cells. Th17 differentiation was enhanced at low interleukin-6 (IL-6) concentrations in absence of Tec, which correlates with increased STAT3 phosphorylation and higher Il23r expression. Therefore, we uncovered a function for Tec in the IL-6 sensing via STAT3 by CD4+ T cells, defining Tec as a fine-tuning negative regulator of Th17 differentiation. Subsequently, by using the IL-17A fate mapping mouse combined with in vivo adoptive transfer models, we demonstrated that Tec not only restrained effector Th17 differentiation but also pathogenicity and plasticity in a T-cell intrinsic manner. Our data further suggest that Tec regulates inflammatory Th17-driven immune responses directly impacting disease severity in a T-cell-driven colitis model. Notably, consistent with the in vitro findings, elevated levels of the IL-23 receptor (IL-23R) were observed on intestinal pre- and postconversion Th17 cells isolated from diseased Tec-/- mice subjected to adoptive transfer colitis, highlighting a fundamental role of Tec in restraining IL-23R expression, likely via the IL-6-STAT3 signaling axis. Taken together, these findings identify Tec as a negative regulator of Th17 differentiation, pathogenicity, and plasticity, contributing to the mechanisms which help T cells to orchestrate optimal immune protection and to restrain immunopathology.

NCOR1 Orchestrates Transcriptional Landscapes and Effector Functions of CD4+ T Cells.

The differentiation of naïve CD4+ T cells into T helper (Th) subsets is key for a functional immune response and has to be tightly controlled by transcriptional and epigenetic processes. However, the function of cofactors that connect gene-specific transcription factors with repressive chromatin-modifying enzymes in Th cells is yet unknown. Here we demonstrate an essential role for nuclear receptor corepressor 1 (NCOR1) in regulating naïve CD4+ T cell and Th1/Th17 effector transcriptomes. Moreover, NCOR1 binds to a conserved cis-regulatory element within the Ifng locus and controls the extent of IFNγ expression in Th1 cells. Further, NCOR1 controls the survival of activated CD4+ T cells and Th1 cells in vitro, while Th17 cell survival was not affected in the absence of NCOR1. In vivo, effector functions were compromised since adoptive transfer of NCOR1-deficient CD4+ T cells resulted in attenuated colitis due to lower frequencies of IFNγ+ and IFNγ+IL-17A+ Th cells and overall reduced CD4+ T cell numbers. Collectively, our data demonstrate that the coregulator NCOR1 shapes transcriptional landscapes in CD4+ T cells and controls Th1/Th17 effector functions.

The zinc-finger transcription factor MAZR regulates iNKT cell subset differentiation.

Invariant natural killer T (iNKT) cells represent a subgroup of innate-like T cells and play an important role in immune responses against certain pathogens. In addition, they have been linked to autoimmunity and antitumor immunity. iNKT cells consist of several subsets with distinct functions; however, the transcriptional networks controlling iNKT subset differentiation are still not fully characterized. Myc-associated zinc-finger-related factor (MAZR, also known as PATZ1) is an essential transcription factor for CD8+ lineage differentiation of conventional T cells. Here, we show that MAZR plays an important role in iNKT cells. T-cell lineage-specific deletion of MAZR resulted in an iNKT cell-intrinsic defect that led to an increase in iNKT2 cell numbers, concurrent with a reduction in iNKT1 and iNKT17 cells. Consistent with the alteration in the subset distribution, deletion of MAZR also resulted in an increase in the percentage of IL-4-producing cells. Moreover, MAZR-deficient iNKT cells displayed an enhanced expression of Erg2 and ThPOK, key factors for iNKT cell generation and subset differentiation, indicating that MAZR controls iNKT cell development through fine-tuning of their expression levels. Taken together, our study identified MAZR as an essential transcription factor regulating iNKT cell subset differentiation and effector function.

Profiling chemotherapy-associated myelotoxicity among Chinese gastric cancer population receiving cytotoxic conventional regimens: epidemiological features, timing, predictors and clinical impacts.

Objectives: We aim to evaluate the epidemiological features, timing, predictors and clinical impacts of chemotherapy-associated myelotoxicity in Chinese gastric cancer population receiving six established cytotoxic conventional regimens (CF/XP, EC(O)F/EC(O)X, DC(O)F/DC(O)X, PC(O)F/PC(O)X, FOLFOX4, or mFOLFOX7/XELOX). Patients and methods: A 4-year multicenter, prospective, observational study was conducted in multiple hospitals/institutes spanning three major regions in China. A total of 1,285 patients with gastric cancer, treated with six selected regimens between 2010 and 2014 were included. Kaplan-meier analysis was applied to estimate the time to develop myelotoxicity events for each regimen. Multivariable logistic regression model was built to identify predictors associated with chemotherapy-induced myelotoxicity, evaluating detailed specific factors of patients, disease and treatment patterns. Results: Triplet regimens were associated with more moderate-to-severe myelotoxicity events than doublet regimens. DC(O)F/DC(O)X group presented with moderate-to-severe anaemia, thrombocytopenia, and leukopenia earlier than other regimen groups, with median time of 3.5, 4.8 and 3.3 cycles, respectively. PC(O)F/PC(O)X group had a shortest time to develop Moderate-to-Severe neutropenia (median time, 3.3 cycles). Multivariate analysis identified several independent predictors for moderate-to-severe myelotoxicity, including: baseline Hb<12.0 g/dL, male gender, KPS<80, previously treated with surgery, tumor located at gastroesophageal junction(GEJ), DC(O)F/DC(O)X regimen, palliative intent, triplet combination therapy and No. of cycles received≥4. Dose reductions≥20% occurred in 16.7% of patients and treatment delays≥7 days presented in 21.1% of patients, resulting in patients receiving an actual average Relative Dose Intensity (RDI) of 0.733. Conclusions: Myelotoxicity events were frequently observed within the gastric cancer population undertaking multicycle polychemotherapy. Predictive models based on risk factors identified for moderate-to-severe myelotoxicity should enable the targeted use of appropriate supportive care in an effort to facilitate the delivery of full chemotherapy doses on schedule.

Bile acids in regulation of inflammation and immunity: friend or foe?

Apart from their pivotal role in dietary lipid absorption and cholesterol homeostasis, bile acids (BAs) are increasingly recognised as important signalling molecules in the regulation of systemic endocrine functions. As such BAs are natural ligands for several nuclear hormone receptors and G-protein-coupled receptors. Through activating various signalling pathways, BAs not only regulate their own synthesis, enterohepatic recirculation and metabolism, but also immune homeostasis. This makes BAs attractive therapeutic agents for managing metabolic and inflammatory liver disorders. Recent experimental and clinical evidence indicates that BAs exert beneficial effects in cholestatic and metabolically driven inflammatory diseases. This review elucidates how different BAs function as pathogenetic factors and potential therapeutic agents for inflammation-driven liver diseases, focusing on their role in regulation of inflammation and immunity.

[Kinetics of Cu crossing human erythrocyte membrane].

This study was aimed to investigate various factors influencing the proceduction of Cu(II) crossing human erythrocyte membrane, including concentration of Cu²âº, pH value of the medium, temperature and time of incubation, and to derive kinetic equation of Cu(II) crossing human erythrocyte membrane. Suspension red blood cells were incubated by Cu²âº, then content of Cu²âº crossed human erythrocyte membrane was determined by atomic absorption spectrometry under various conditions after digestion. The results showed that content of Cu²âº crossed human erythrocyte membrane increased with the increase of extracellular Cu²âº and enhancement of incubation temperature, and the content of Cu²âº crossed human erythrocyte membrane showed a increasing tendency when pH reached to 6.2-7.4, and to maximum at pH 7.4, then gradually decreased at range of pH 7.4-9.2. It is concluded that the Cu²âº crossing human erythrocyte has been confirmed to be the first order kinetics characteristics within 120 min, and the linear equation is 10³ × Y = 0.0497t +6.5992.

[Comprehensive study of lead pollution in atmospheric aerosol of Shanghai].

The lead contamination, lead species and source assignment were studied by a combination of several analytical techniques such as Proton-induced X-ray emission analysis (PIXE), Proton microprobe (micro-PIXE), Inductively coupled plasma-mass spectrometry (ICP-MS) and extended X-ray absorption fine structure (EXAFS) techniques. The results indicate that the lead concentration in the air of Shanghai gradually decreased over the last years. The atmospheric lead concentration of PM10 in the winter of 2002 was 369 ng x m(-3), which had declined by 28% in 2001, and in the winter of 2003 it decreased further to 237 ng x m(-3). The main lead species in the samples collected in the winter of 2003 were probably PbCl2, PbSO4 and PbO. The source apportionment was calculated in terms of the combination of lead isotope ratios and lead mass balance method, assisted by single particle analysis with micro-PIXE and pattern recognition. The results suggest that the major contributors of atmospheric lead pollution in Shanghai are the coal combustion dust; the metallurgic dust and vehicle exhaust particles, with a contribution around 50%, 35% and 15%, respectively. It probably is the first time to give a city a quantitative estimation of lead pollution contribution from emission sources. The influence from leaded gasoline was still present in the atmosphere by four or five years after the phasing out of leaded gasoline.