Small cyst size and lack of growth as negative predictors of malignant transformation in low-risk intraductal papillary mucinous neoplasms of the pancreas: A systematic review and meta-analysis.

BACKGROUND AND AIM: For branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) without worrisome features (WFs) or high-risk stigmata (HRS), current guidelines recommend surveillance. However, these intraductal papillary mucinous neoplasm (IPMNs), especially the small and stable-sized ones, carry a low risk of malignant transformation. Our aim was to assess whether small cyst size and absence of rapid growth provide reassurance against the development of WFs/HRS and malignancy (high-grade dysplasia (HGD) or pancreatic cancer (PC)). METHODS: PubMed/Medline, Embase, the Cochrane Library and the Web of Science Core Collection were systematically searched from inception to May 2023 to identify studies investigating surveillance outcomes of low-risk BD-IPMNs. Studies assessing baseline cyst size and/or growth in relation to WFs/HRS and/or HGD/PC were included. The Newcastle-Ottawa scale tool was used to assess study quality. RESULTS: Of the 1937 identified manuscripts, 21 studies were eligible for inclusion. The quality of these studies was considered reasonable. A negative association between cyst size and WFs/HRS development was found in 11 out of 13 relevant studies, but only one out of nine studies reported a negative association between size and malignancy. Regarding cyst growth, four out of six studies described a negative association with the development of WFs/HRS, and all six reported a negative association with malignancy. The pooled relative risk (RR) of developing WFs/HRS or malignancy for cysts ≤15 mm was 0.37 (95% CI 0.25-0.57) and the RR of developing malignancy for cyst growth <2-2.5 mm/year was 0.04 (95% CI 0.02-0.09)). CONCLUSION: This systematic review and meta-analysis shows that small and stable-sized low-risk BD-IPMNs are associated with a markedly low progression rate, with stable cyst size being the most reassuring feature. Because of substantial heterogeneity in definitions and reported outcome measures, prospective studies are needed to confirm that surveillance of small and stable sized cyst can be de-intensified or even discontinued.

Assessment of Glucose and HbA1c Monitoring in a Pancreatic Cancer Surveillance Program for High-Risk Individuals.

INTRODUCTION: Several studies suggest that new-onset diabetes mellitus is an early manifestation of pancreatic ductal adenocarcinoma (PDAC). Therefore, the International Cancer of the Pancreas Screening Consortium recommends glucose and hemoglobin A1c (HbA1c) monitoring in high-risk individuals (HRIs) undergoing surveillance. However, evidence that such monitoring improves PDAC detection is lacking. Our aim was to investigate the association between serum glucose and HbA1c values and the development of PDAC in HRIs undergoing surveillance. METHODS: Participants were recruited from the familial pancreatic cancer surveillance cohort, which follows hereditary predisposed HRIs yearly by magnetic resonance imaging and/or endoscopic ultrasound and blood sampling. Those who underwent fasting glucose and/or HbA1c monitoring at least once were eligible candidates. RESULTS: Four hundred four HRIs met the inclusion criteria. During a median follow-up of 41 months (range 14-120), 9 individuals developed PDAC and 4 (without PDAC) were diagnosed with new-onset diabetes mellitus. Glucose levels ranged from 3.4 to 10.7 mmol/L (mean 5.6 ± 0.7) and HbA1c levels from 25 to 68 mmol/mol (mean 37.7 ± 4.1). The mean values did not differ significantly between PDAC cases and controls. The percentage of individuals with at least one elevated value were comparable between PDAC cases and controls for glucose (33% and 27%, P = 0.707) and HbA1c (22% and 14%, P = 0.623). No consistent glucose or HbA1c trends over time suggested a correlation with PDAC development. DISCUSSION: In this HRI surveillance cohort, measuring glucose and HbA1c values did not contribute to PDAC detection. Larger and longer-term studies are needed to determine the final role of glucose and HbA1c monitoring in PDAC surveillance.

Vascular smooth muscle cell-derived exosomes promote osteoblast-to-osteocyte transition via ß-catenin signaling.

Blood vessel growth and osteogenesis in the skeletal system are coupled; however, fundamental aspects of vascular function in osteoblast-to-osteocyte transition remain unclear. Our study demonstrates that vascular smooth muscle cells (VSMCs), but not endothelial cells, are sufficient to drive bone marrow mesenchymal stromal cell-derived osteoblast-to-osteocyte transition via ß-catenin signaling and exosome-mediated communication. We found that VSMC-derived exosomes are loaded with transcripts encoding proteins associated with the osteocyte phenotype and members of the WNT/ß-catenin signaling pathway. In contrast, endothelial cell-derived exosomes facilitated mature osteoblast differentiation by reprogramming the TGFB1 gene family and osteogenic transcription factors osterix (SP7) and RUNX2. Notably, VSMCs express significant levels of tetraspanins (CD9, CD63, and CD81) and drive the intracellular trafficking of exosomes with a lower membrane zeta potential than those from other cells. Additionally, the high ATP content within these exosomes supports mineralization mechanisms, as ATP is a substrate for alkaline phosphatase. Osteocyte function was further validated by RNA sequencing, revealing activity in genes related to intermittent mineralization and sonic hedgehog signaling, alongside a significant increase in TNFSF11 levels. Our findings unveil a novel role of VSMCs in promoting osteoblast-to-osteocyte transition, thus offering new insights into bone biology and homeostasis, as well as in bone-related diseases. Clinically, these insights could pave the way for innovative therapeutic strategies targeting VSMC-derived exosome pathways to treat bone-related disorders such as osteoporosis. By manipulating these signaling pathways, it may be possible to enhance bone regeneration and improve skeletal health in patients with compromised bone structure and function.

Systematic review: Patient-related, microbial, surgical, and histopathological risk factors for endoscopic post-operative recurrence in patients with Crohn's disease.

BACKGROUND: Risk stratification for endoscopic post-operative recurrence (ePOR) in Crohn's disease (CD) is required to identify patients who would benefit most from initiation of prophylactic medication and intensive monitoring of recurrence. AIMS: To assess the current evidence on patient-related, microbial, surgical and histopathological risk factors for ePOR in patients with CD after ileocolic (re-)resection. METHODS: Multiple online databases (Embase, MEDLINE, Web of Science and Cochrane Library) were searched up to March 2024. Studies with reported associations of patient-related, microbial, surgical and/or histopathological factors for ePOR (i.e., Rutgeerts' score ≥i2 or modified Rutgeerts' score ≥i2a) were included. The risk of bias was assessed with the Newcastle-Ottawa Scale for observational cohort studies and case-control studies. RESULTS: In total, 47 studies were included (four RCTs, 29 cohort studies, 12 case-control studies, one cross-sectional study and one individual participant data meta-analysis) including 6006 patients (median sample size 87 patients [interquartile range 46-170]). Risk of bias assessment revealed a poor quality in 41% of the studies. An association was reported in multiple studies of ePOR with active smoking at and post-surgery, male sex and prior bowel resection. A heterogeneous association with ePOR was reported for other risk factors included in the current guidelines (penetrating disease, perianal disease, younger age, extensive small bowel disease and presence of granulomas in the resection specimen or myenteric plexitis in the resection margin), and other patient-related, microbial, surgical and histopathological factors. CONCLUSION: Risk factors for ePOR in international guidelines are not consistently reported as risk factors in current literature except for active smoking and prior bowel resection. To develop evidence-based, personalised strategies, large prospective studies are warranted to identify risk factors for ePOR. Validation studies of promising (bio)markers are also required.

Calix[6]arene dismantles extracellular vesicle biogenesis and metalloproteinases that support pancreatic cancer hallmarks.

Many challenges are faced in pancreatic cancer treatment due to late diagnosis and poor prognosis because of high recurrence and metastasis. Extracellular vesicles (EVs) and matrix metalloproteinases (MMPs), besides acting in intercellular communication, are key players in the cancer cell plasticity responsible for initiating metastasis. Therefore, these entities provide valuable targets for the development of better treatments. In this context, this study aimed to evaluate the potential of calix[6]arene to disturb the release of EVs and the activity of MMPs in pancreatic cancer cells. We found a correlation between the endocytic-associated mediators and the prognosis of pancreatic cancer patients. We observed a more active EV machinery in the pancreatic cancer cell line PANC-1, which was reduced three-fold by treatment with calix[6]arene at subtoxic concentration (5 µM; p ã€ˆ0,001). We observed the modulation of 186 microRNAs (164 miRNAs upregulated and 22 miRNAs downregulated) upon calix[6]arene treatment. Interestingly, some of them as miR-4443 and miR-3909, regulates genes HIF1A e KIF13A that are well known to play a role in transport of vesicles. Furthermore, Calix[6]arene downmodulated matrix metalloproteinases (MMPs) -2 and - 9 and disturbed the viability of pancreatic organoids which recapitulate the cellular heterogeneity, structure, and functions of primary tissues. Our findings shed new insights on calix[6]arene's antitumor mechanism, including its intracellular effects on vesicle production and trafficking, as well as MMP activity, which may harm the tumor microenvironment and contribute to a reduction in cancer cell dissemination, which is one of the challenges associated with high mortality in pancreatic cancer.

IL-6 facilitates cross-talk between epithelial cells and tumor- associated macrophages in Helicobacter pylori-linked gastric carcinogenesis.

PURPOSE: Helicobacter pylori (H. pylori) is a significant risk factor for development of gastric cancer (GC), one of the deadliest malignancies in the world. However, the mechanism by which H. pylori induces gastric oncogenesis remains unclear. Here, we investigated the function of IL-6 in gastric oncogenesis and macrophage-epithelial cell interactions. METHODS: We analyzed publicly available datasets to investigate the expression of IL-6 and infiltration of M2 macrophages in GC tissues, and determine the inter-cellular communication in the context of IL-6. Human gastric epithelial and macrophage cell lines (GES-1 and THP-1-derived macrophages, respectively) were used in mono- and co-culture experiments to investigate autocrine-and paracrine induction of IL-6 expression in response to H. pylori or IL-6 stimulation. RESULTS: We found that IL-6 is highly expressed in GC and modulates survival. M2 macrophage infiltration is predominant in GC and drives an IL-6 mediated communication with gastric epithelium cells. In vitro, IL-6 triggers its own expression in GES-1 and THP-1-derived macrophages cells. In addition, these cell lines are able to upregulate each other's IL-6 levels in an autocrine fashion, which is enhanced by H. pylori stimulation. CONCLUSION: This study indicates that IL-6 in the tumor microenvironment is essential for intercellular communication. We show that H. pylori enhances an IL-6-driven autocrine and paracrine positive feedback loop between macrophages and gastric epithelial cells, which may contribute to gastric carcinogenesis.

Increased Prevalence of Autoimmune Gastritis in Patients with a Gastric Precancerous Lesion.

Background: Autoimmune gastritis (AIG), characterized with the presence of anti-parietal-cell antibodies (APCA), is a risk factor for gastric cancer. However, AIG may go underdiagnosed, especially in the case of H. pylori infection and the presence of gastric precancerous lesions (GPL), due to the ambiguous pathology and delayed symptom onset. Aim: Investigate the prevalence and characteristics of AIG in GPL patients. Methods: Prevalence of AIG was determined with the presence of APCA in patients with GPL (n = 256) and the control group (n = 70). Pathological characteristics and levels of gastrin 17 (G17), pepsinogen (PG) I and II and anti-Helicobacter pylori IgG were assessed in GPL cases, and the severity of intestinal metaplasia and gastric atrophy was scored by expert pathologists. Results: APCA positivity was observed in 18% of cases vs. 7% of controls (p = 0.033). Only 3/256 patients were previously diagnosed with AIG. The presence of APCA was associated with corpus-limited and extended GPL. A receiver operating curve analysis demonstrated that the G17 and PGI/II ratio could identify APCA-positive patients within GPL cases (AUC: 0.884). Conclusions: The prevalence of AIG is higher in patients with GPL but goes undiagnosed. Using G17 and PG I/II as diagnostic markers can help to identify patients with AIG and improve surveillance programs for patients with GPL.

The use of non-invasive stool tests for verification of Helicobacter pylori eradication and clarithromycin resistance.

BACKGROUND: Clarithromycin resistance of Helicobacter pylori (H. pylori) represents a major challenge in eradication therapy. In this study, we assessed if non-invasive stool tests can be used to verify successful H. pylori eradication and determine clarithromycin resistance. MATERIALS AND METHODS: In this prospective study, patients undergoing urea breath testing (UBT) for confirmation of H. pylori eradication were asked to collect the stool as both a dry fecal sample and fecal immunochemical test (FIT). Stool H. pylori antigen testing (SAT) was performed on these samples and assessed for its accuracy in eradication verification. Type and duration of antibiotic treatment were retrospectively collected from patient records and compared with clarithromycin resistance determined by PCR of stool samples. RESULTS: H. pylori eradication information was available for a total of 145 patients (42.7% male, median age: 51.2). Successful eradication was achieved in 68.1% of patients. SAT on FIT samples had similar accuracy for eradication assessment compared to dry fecal samples, 72.1% [95% CI 61.4-81.2] versus 72.2% [95% CI 60.9-81.7]. Clarithromycin resistance rate was 13.4%. CONCLUSION: H. pylori antigen testing on FIT stool samples to verify H. pylori eradication is feasible and has similar accuracy as H. pylori antigen testing on dry stool samples. Dry stool, but not FIT, was suitable for non-invasive identification of H. pylori clarithromycin resistance by rt-PCR personalizing antibiotic treatment strategies without the need for invasive diagnostics is desirable, as the cure rate of first-line empirical H. pylori treatment remains low.

Mutation Analysis of Pancreatic Juice and Plasma for the Detection of Pancreatic Cancer.

Molecular profiling may enable earlier detection of pancreatic cancer (PC) in high-risk individuals undergoing surveillance and allow for personalization of treatment. We hypothesized that the detection rate of DNA mutations is higher in pancreatic juice (PJ) than in plasma due to its closer contact with the pancreatic ductal system, from which pancreatic cancer cells originate, and higher overall cell-free DNA (cfDNA) concentrations. In this study, we included patients with pathology-proven PC or intraductal papillary mucinous neoplasm (IPMN) with high-grade dysplasia (HGD) from two prospective clinical trials (KRASPanc and PACYFIC) for whom both PJ and plasma were available. We performed next-generation sequencing on PJ, plasma, and tissue samples and described the presence (and concordance) of mutations in these biomaterials. This study included 26 patients (25 PC and 1 IPMN with HGD), of which 7 were women (27%), with a median age of 71 years (IQR 12) and a median BMI of 23 kg/m2 (IQR 4). Ten patients with PC (40%) were (borderline) resectable at baseline. Tissue was available from six patients (resection n = 5, biopsy n = 1). A median volume of 2.9 mL plasma (IQR 1.0 mL) and 0.7 mL PJ (IQR 0.1 mL, p < 0.001) was used for DNA isolation. PJ had a higher median cfDNA concentration (2.6 ng/µL (IQR 4.2)) than plasma (0.29 ng/µL (IQR 0.40)). A total of 41 unique somatic mutations were detected: 24 mutations in plasma (2 KRAS, 15 TP53, 2 SMAD4, 3 CDKN2A 1 CTNNB1, and 1 PIK3CA), 19 in PJ (3 KRAS, 15 TP53, and 1 SMAD4), and 8 in tissue (2 KRAS, 2 CDKN2A, and 4 TP53). The mutation detection rate (and the concordance with tissue) did not differ between plasma and PJ. In conclusion, while the concentration of cfDNA was indeed higher in PJ than in plasma, the mutation detection rate was not different. A few cancer-associated genetic variants were detected in both biomaterials. Further research is needed to increase the detection rate and assess the performance and suitability of plasma and PJ for PC (early) detection.

Overlapping cytokines in H. pylori infection and gastric cancer: A tandem meta-analysis.

Background: Previous evidence indicated that Helicobacter pylori-induced inflammation is the first step towards gastric carcinogenesis. However, investigations of the immunological factors driving this process have shown inconsistencies. We aimed to present a thorough summary of all researched cytokines in relation to H. pylori infection and GC and relate these to global GC risk. Methods: We performed a systematic review and tandem meta-analysis identifying all published studies reporting on serum cytokine levels in H. pylori-infected cases vs. non-infected controls and gastric cancer cases vs. non-gastric cancer controls, with sub-analyses performed to identify global regional differences in cytokine induction and their correlation with GC incidence. Results: Only levels of systemic IL-6 (standardized mean difference [SMD]:0.95, 95%CI [0.45;1.45]) and TNF-α (SMD:0.88, 95%CI [0.46; 1.29]) were significantly increased upon H. pylori infection. Sub-analysis showed that of IL-6 levels were increased upon H. pylori infection in East Asian, Middle Eastern and Southeast Asian cohorts, but not in North America, Europe, Russia and Africa. Serum levels of IL-6, IL-7, IL-10, IL-12, and TNF-α were significantly raised in GC. Exploration of the relationship between serum cytokines changes upon H. pylori infection and regional differences in risk of GC development indicated that the SMD of IL-6 serum levels presents a significant correlation with the relative incidence of GC (r=0.81, p=0.00014). Conclusion: This study shows that H. pylori infection and GC are associated with increased IL-6 and TNF-α levels. Particularly, IL-6 shows region-specific increases that correlate with GC incidence, making it a key contender for the cause of this disease.

An 8q24 Gain in Pancreatic Juice Is a Candidate Biomarker for the Detection of Pancreatic Cancer.

Secretin-stimulated pancreatic juice (PJ), collected from the duodenum, presents a valuable biomarker source for the (earlier) detection of pancreatic cancer (PC). Here, we evaluate the feasibility and performance of shallow sequencing to detect copy number variations (CNVs) in cell-free DNA (cfDNA) from PJ for PC detection. First, we confirmed the feasibility of shallow sequencing in PJ (n = 4), matched plasma (n = 3) and tissue samples (n = 4, microarray). Subsequently, shallow sequencing was performed on cfDNA from PJ of 26 cases (25 sporadic PC, 1 high-grade dysplasia) and 19 controls with a hereditary or familial increased risk of PC. 40 of the 45 PJ samples met the quality criteria for cfDNA analysis. Nine individuals had an 8q24 gain (oncogene MYC; 23%; eight cases (33%) and one control (6%), p = 0.04); six had both a 2q gain (STAT1) and 5p loss (CDH10; 15%; four cases (7%) and two controls (13%), p = 0.72). The presence of an 8q24 gain differentiated the cases and controls, with a sensitivity of 33% (95% CI 16-55%) and specificity of 94% (95% CI 70-100%). The presence of either an 8q24 or 2q gain with a 5p loss was related to a sensitivity of 50% (95% CI 29-71%) and specificity of 81% (95% CI 54-96%). Shallow sequencing of PJ is feasible. The presence of an 8q24 gain in PJ shows promise as a biomarker for the detection of PC. Further research is required with a larger sample size and consecutively collected samples in high-risk individuals prior to implementation in a surveillance cohort.

Modulation of Indoleamine 2,3-Dioxygenase 1 During Inflammatory Bowel Disease Activity in Humans and Mice.

Background and Aims: Indoleamine 2,3 dioxygenase-1 (IDO1), a key enzyme in tryptophan metabolism, is strongly up-regulated both in human inflammatory bowel disease (IBD) and animal models of colitis, however its role in the pathogenesis is still controversial. In this study, we investigated IDO1 expression and activity in a mouse model of DSS-induced chronic colitis as well as in colon biopsies and sera from IBD patients. Methods: Chronic colitis was induced in mice through the oral administration of dextran sodium sulfate (DSS), and IDO1 activity was induced by i.p. treatment with N-acetyl serotonin (NAS). IDO1 expression and catalytic activity (measured as Kyn/Trp ratio) was evaluated in sera and tissue samples collected from mice and 93 IBD patients under immunotherapy with Vedolizumab (VDZ) or Ustekinumab (UST). Results: Strong up-regulation of IDO1 was found in colons of mice with acute colitis, which follows disease activity. Enhanced IDO1 activity by NAS treatment protects the intestinal mucosa during the recovery phase of chronic colitis. In IBD patients, IDO1 expression and activity correlate with the severity of mucosal inflammation with inflamed regions showing higher IDO1 expression compared to non-inflamed regions within the same patient. Endoscopic response to VDZ/UST treatment is associated with decreased expression of IDO1. Conclusions: This is the first study demonstrating immunomodulatory activity of IDO1 in a chronic mouse model of DSS-induced colitis. As its expression and catalytic activity correlate with the grade of mucosal inflammation and treatment response, IDO1 could represent a promising biomarker for disease severity and treatment monitoring in IBD.

Stromal vascular fraction with platelet-rich plasma injection during surgery is feasible and safe in treatment-refractory perianal fistulising Crohn's disease: A pilot study.

BACKGROUND: An unmet need remains for improved management in perianal fistulising Crohn's disease (pCD). Recently, local administration of adipose-derived cells has shown promising results. AIMS: To assess the safety and feasibility of injection of stromal vascular fraction (SVF) with platelet-rich plasma (PRP) in patients with pCD. METHODS: Patients ≥ 18 years with pCD were included and underwent fistula curettage, SVF with PRP injection, and closure of the internal opening. The primary endpoint was safety at 12 months. The secondary outcomes were complete radiological healing at 3 months (absence of fluid-containing tracts on MRI) and partial and complete clinical response at 3 and 12 months (closure of ≥1, respectively, all treated external opening(s)). RESULTS: Twenty-five patients were included (35 [IQR 25-40] years; 14 [56%] female); median CD duration 4 [IQR 2-8] years. Twenty-four (95%) patients had previously undergone fistula surgery. No adverse events were encountered at lipoharvesting sites. Two (8%) patients were readmitted to hospital and six (24%) underwent unplanned re-interventions. Post-operative MRI (n = 24) showed complete radiological healing in nine (37.5%) patients. Partial clinical response was present in 48% (12/25) at 3 months and in 68% (17/25) at 12 months, and complete clinical closure in five (20%) patients at 3 months and in 10 (40%) patients at 12 months. CONCLUSION: Injection with autologous SVF with PRP is feasible and safe in patients with treatment-refractory pCD. Early complete radiological healing was observed in more than one-third of patients, and clinical response in two-thirds of patients at 12 months.

Intelectin-1 binds and alters the localization of the mucus barrier-modifying bacterium Akkermansia muciniphila.

Intelectin-1 (ITLN1) is a lectin secreted by intestinal epithelial cells (IECs) and upregulated in human ulcerative colitis (UC). We investigated how ITLN1 production is regulated in IECs and the biological effects of ITLN1 at the host-microbiota interface using mouse models. Our data show that ITLN1 upregulation in IECs from UC patients is a consequence of activating the unfolded protein response. Analysis of microbes coated by ITLN1 in vivo revealed a restricted subset of microorganisms, including the mucolytic bacterium Akkermansia muciniphila. Mice overexpressing intestinal ITLN1 exhibited decreased inner colonic mucus layer thickness and closer apposition of A. muciniphila to the epithelial cell surface, similar to alterations reported in UC. The changes in the inner mucus layer were microbiota and A. muciniphila dependent and associated with enhanced sensitivity to chemically induced and T cell-mediated colitis. We conclude that by determining the localization of a select group of bacteria to the mucus layer, ITLN1 modifies this critical barrier. Together, these findings may explain the impact of ITLN1 dysregulation on UC pathogenesis.

Ustekinumab Tissue and Serum Levels in Patients With Crohn's Disease Are Closely Correlated Though Not Consistently Associated With Objective Response After Induction.

BACKGROUND: Ustekinumab (UST), which targets p40/interleukin (IL)-23 and IL-12, is an effective treatment for Crohn's disease (CD). Therapeutic drug monitoring may optimize UST posology. The aim of this study was to investigate UST and IL-23 serum and tissue concentrations in relation to mucosal inflammation and treatment response at an early time point. METHODS: CD patients starting UST between December 2016 and November 2018 were prospectively enrolled. Endoscopies were performed at baseline and week 16. UST and IL-23 serum and tissue concentrations were measured at week 16. Clinical and biochemical response were defined as decline of ≥3 points in Harvey-Bradshaw Index and reduction of ≥50% in fecal calprotectin levels. Endoscopic response was defined as a ≥50% decline in Simple Endoscopic Score or a decline of ≥1 points in Rutgeerts score. Histological remission was defined as Global Histologic Disease Activity Score ≤4. RESULTS: Of 56 included patients, 17 (30%) of 56 showed clinical response, 16 (30%) of 53 showed biochemical response, and 20 (36%) of 56 showed endoscopic response. UST, but not IL-23, concentration in biopsies was correlated to levels in corresponding sera (P < .0001). No correlation was found between UST tissue levels and treatment response. Patients achieving biochemical response showed significantly higher UST serum levels (3.12 µg/mL vs 1.41 µg/mL; P = .01). Tissue IL-23-to-UST ratio correlated with mucosal inflammation (P = .01). CONCLUSIONS: This is the first study to demonstrate a correlation between serum and tissue UST levels. While tissue IL-23-to-UST ratio correlated with mucosal inflammation, UST serum levels were more indicative for biochemical response. The role of UST levels for therapeutic drug monitoring in inflammatory bowel disease needs further research.

Ustekinumab (UST) serum levels correlate with UST tissue levels in patients with Crohn's disease. Tissue interleukin-23-to-UST ratio correlates with histological inflammation (Global Histologic Disease Activity Score). Serum UST levels correlate with biochemical response (reduction of ≥50% in fecal calprotectin levels).

Constitutive programmed death ligand 1 expression protects gastric G-cells from Helicobacter pylori-induced inflammation.

INTRODUCTION: Gastric intestinal metaplasia (GIM) is a premalignant lesion, highly associated with Helicobacter pylori infection. Previous studies have shown that H. pylori is able to induce the expression of programmed death ligand 1 (PD-L1), an inhibitory immune modulator, in gastric cells. Our aim was to investigate whether tissues from GIM patients may exploit PD-L1 expression upon H. pylori infection to evade immunosurveillance. METHODS: Immunohistochemistry was performed for PD-L1 and enteroendocrine markers somatostatin and gastrin on samples derived from a cohort of patients with known GIM, both before and after H. pylori eradication. To determine the identity of any observed PD-L1-positive cells, we performed multiplex immunofluorescent staining and analysis of single-cell sequencing data. RESULTS: GIM tissue was rarely positive for PD-L1. In normal glands from GIM patients, PD-L1 was mainly expressed by gastrin-positive G-cells. While the D-cell and G-cell compartments were both diminished 2-fold (p = .015 and p = .01, respectively) during H. pylori infection in the normal antral tissue of GIM patients, they were restored 1 year after eradication. The total number of PD-L1-positive cells was not affected by H. pylori, but the percentage of PD-L1-positive G-cells was 30% higher in infected subjects (p = .011), suggesting that these cells are preferentially rescued from destruction. CONCLUSIONS: Antral G-cells frequently express PD-L1 during homeostasis. G-cells seem to be protected from H. pylori-induced immune destruction by PD-L1 expression. GIM itself does not express PD-L1 and is unlikely to escape immunosurveillance via expression of PD-L1.

Kinome profiling of cholangiocarcinoma organoids reveals potential druggable targets that hold promise for treatment stratification.

BACKGROUND: Cholangiocarcinoma is a rare but lethal cancer of the biliary tract. Its first-line treatment is currently restricted to chemotherapy, which provides limited clinical benefit. Kinase inhibitors targeting oncogenic intracellular signaling have changed the treatment paradigm of cancer over the last decades. However, they are yet to be widely applied in cholangiocarcinoma therapy. Cholangiocarcinoma has marked molecular heterogeneity, which complicates the discovery of new treatments and requires patient stratification. Therefore, we investigated whether a commercial kinome profiling platform could predict druggable targets in cholangiocarcinoma. METHODS: Kinase activity in patient-derived cholangiocarcinoma organoids, non-tumorous adjacent tissue-derived and healthy donor-derived intrahepatic cholangiocyte organoids was determined using the PamChip® phosphotyrosine kinase microarray platform. Kinome profiles were compared and correlated with RNA sequencing and (multi-)kinase inhibitor screening of the cholangiocarcinoma organoids. RESULTS: Kinase activity profiles of individual cholangiocarcinoma organoids are different and do not cluster together. However, growth factor signaling (EGFR, PDGFRß) and downstream effectors (MAPK pathway) are more active in cholangiocarcinoma organoids and could provide potential druggable targets. Screening of 31 kinase inhibitors revealed several promising pan-effective inhibitors and compounds that show patient-specific efficacy. Kinase inhibitor sensitivity correlated to the activity of its target kinases for several inhibitors, signifying them as potential predictors of response. Moreover, we identified correlations between drug response and kinases not directly targeted by those drugs. CONCLUSIONS: In conclusion, kinome profiling is a feasible method to identify druggable targets for cholangiocarcinoma. Future studies should confirm the potential of kinase activity profiles as biomarkers for patient stratification and precision medicine.