Novel endoscopic scoring system for immune mediated colitis: a multicenter retrospective study of 674 patients.

BACKGROUND AND AIMS: No endoscopic scoring system has been established for immune-mediated colitis (IMC). This study aimed to establish such a system for IMC and explore its utility in guiding future selective immunosuppressive therapy (SIT) use compared to clinical symptoms. METHODS: This retrospective, international, 14-center study included 674 patients who developed IMC after immunotherapy and underwent endoscopic evaluation. Ten endoscopic features were selected by group consensus and assigned 1 point each to calculate an IMC endoscopic score (IMCES). IMCES cutoffs were chosen to maximize specificity for SIT use. This specificity was compared between IMCESs, and clinical symptoms were graded according to a standardized instrument. RESULTS: A total of 309 (45.8%) patients received SIT. IMCES specificity for SIT use was 82.8% with a cutoff of 4. The inclusion of ulceration as a mandatory criterion resulted in higher specificity (85.0% for a cutoff of 4). In comparison, the specificity of a Mayo endoscopic subscore of 3 was 74.6%, and the specificity of clinical symptom grading was much lower at 27.4% and 12.3%, respectively. Early endoscopy was associated with timely SIT use (P < .001; r = 0.4084). CONCLUSIONS: This is the largest multicenter study to devise an endoscopic scoring system to guide IMC management. An IMCES cutoff of 4 has a higher specificity for SIT use than clinical symptoms, supporting early endoscopic evaluation for IMC.

Caustic ingestions over 10 years in Victoria, Australia: high rates in migrants and women.

BACKGROUND: Caustic ingestion is relatively common in developing countries and can result in life-threatening sequelae. There is limited understanding of the epidemiology and incidence in Australia. AIMS: This statewide 10-year audit aims to document the rate of caustic injury in a defined Australian pouplation. METHODS: A retrospective review was conducted over 10 years (2007-2016), including all admissions to hospitals in Victoria. This includes a population of 5.9 million people and 22 hospitals. RESULTS: Three hundred and eighty-four cases of caustic ingestion were admitted to hospital between January 2007 and December 2016. The overall incidence was 7 cases/million/year. This cohort included 217 (56.5%) females, 193 (50.2%) overseas born patients and 196 (51%) people with a history of mental illness. The countries of birth with the highest incidence of caustic ingestion were Ethiopia (11 patients; 227 cases/million/year; relative risk (RR) 31.7; P < 0.0001), Sudan (11 patients; 161 cases/million/year; RR 22.6; P < 0.0001) and India (38 patients; 27 cases/million/year; RR 3.9; P < 0.0001). All had a significantly higher incidence than the Australian-born population of only 6.5 cases/million/year (RR 0.4; P < 0.0001). Of those born in India, Sudan and Ethiopia, rates of females (72%) were considerably higher than males. The overall mortality rate in this cohort was 2.3%. CONCLUSIONS: Caustic ingestion remains a significant cause of morbidity and health expenditure in Victoria, particularly among vulnerable groups such as recent female migrants from areas in Africa and India. The high frequency of events seen in migrant populations highlights the significant need for awareness of risks in these groups for the development of possible prevention strategies that are required.

Vanishing bile duct syndrome associated with pazopanib after progression on pembrolizumab.

Pazopanib, a tyrosine kinase inhibitor, has been a standard first-line treatment for metastatic renal cell carcinoma (mRCC). Recent trials combining pazopanib with programmed cell death protein 1 (PD-1) inhibitors, including pembrolizumab, have shown excessive hepatotoxicity. We report a case of fatal hepatotoxicity from vanishing bile duct syndrome (VBDS) associated with pazopanib treatment, in a patient previously exposed to pembrolizumab. This is the first report of pazopanib-induced VBDS. We postulate whether prior exposure to pembrolizumab predisposed towards pazopanib-induction of VBDS, and discuss potential risks of sequential PD-1 inhibitor followed by pazopanib in mRCC, due to prolonged half-lives of PD-1 inhibitors.

The emerging role of the thioredoxin system in angiogenesis.

Although there have been a multitude of studies, the mechanisms of angiogenesis remain incompletely understood. Increasing evidence suggests that cellular redox homeostasis is an important regulator of angiogenesis. The thioredoxin (TRX) system functions as an endogenous antioxidant that can exert influence over endothelial cell function via modulation of cellular redox status. It has become apparent that the cytosolic TRX1 isoform participates in both canonical and novel angiogenic signaling pathways and may represent an avenue for therapeutic exploitation. Recent studies have further identified a role for the mitochondrial isoform TRX2 in ischemia-induced angiogenesis. TRX-interacting protein (TXNIP) is the endogenous inhibitor of TRX redox activity that has been implicated in growth factor-mediated angiogenesis. As TXNIP is strongly induced by glucose, this molecule could be of consequence to disordered angiogenesis manifest in diabetes mellitus. This review will focus on data implicating the TRX system in endothelial cell homeostasis and angiogenesis.

Epidemiology and outcomes of marked elevations of alanine aminotransferase >1000 IU/L in an Australian cohort.

BACKGROUND AND AIM: Marked elevations of alanine aminotransferase (ALT) are caused by a limited number of underlying pathologies, including hepatic ischemia, drugs/toxins, viral hepatitis, and-rarely-autoimmune hepatitis. The aim of this study was to determine the relative incidence of pathologies resulting in ALT greater than 1000 IU/L and factors predicting clinical outcomes in an Australian cohort. METHODS: A retrospective cohort study of all adult patients with ALT levels greater than 1000 IU/L between January 2013 and December 2015 was conducted at a large teaching hospital network in Australia. Multivariable logistic regression analysis was used to determine predictors of etiology and mortality. RESULTS: There were 287 patients identified with ALT levels greater than 1000 IU/L. The most common causes were ischemia (44%), drugs/toxins (19%), biliary obstruction (16%), and viral hepatitis (7%). Independent predictors of a diagnosis of ischemic hepatitis included (adjusted odds ratio; 95% confidence interval): hypotension (29.2; 8.2-104.7), chronic obstructive pulmonary disease (COPD) (20.2; 2.8-145.3), coronary artery disease (12.9; 1.7-98.9), congestive cardiac failure (7.8; 1.2-49.2), diabetes mellitus (7.4; 1.6-33.9), metabolic acidosis (6.2; 2.0-19.4), gamma-glutamyltransferase < 135 IU/L (5.1; 1.5-17.6), and albumin <34 g/L (3.4; 1.1-11.0). Independent risk factors for all-cause 28-day mortality included: septic shock (14.7; 4.3-50.7), metabolic acidosis (7.3; 2.5-21.3), history of COPD (5.4; 1.6-17.8), cardiogenic shock (4.3; 1.6-11.7), prothrombin time ≥ 20 s (3.7; 1.5-9.2), and age ≥ 65 years (3.0; 1.3-7.2). CONCLUSIONS: Ischemic hepatitis was the most common cause of ALT levels greater than 1000 IU/L and was associated with high mortality.

Epigenetic inactivation of a cluster of genes flanking MLH1 in microsatellite-unstable colorectal cancer.

Biallelic promoter methylation and transcriptional silencing of the MLH1 gene occurs in the majority of sporadic colorectal cancers exhibiting microsatellite instability due to defective DNA mismatch repair. Long-range epigenetic silencing of contiguous genes has been found on chromosome 2q14 in colorectal cancer. We hypothesized that epigenetic silencing of MLH1 could occur on a regional scale affecting additional genes within 3p22, rather than as a focal event. We studied the levels of CpG island methylation and expression of multiple contiguous genes across a 4 Mb segment of 3p22 including MLH1 in microsatellite-unstable and -stable cancers, and their paired normal colonic mucosa. We found concordant CpG island hypermethylation, H3-K9 dimethylation and transcriptional silencing of MLH1 and multiple flanking genes spanning up to 2.4 Mb in microsatellite-unstable colorectal cancers. This region was interspersed with unmethylated genes, which were also transcriptionally repressed. Expression of both methylated and unmethylated genes was reactivated by methyltransferase and histone deacetylase inhibitors in a microsatellite-unstable colorectal carcinoma cell line. Two genes at the telomeric end of the region were also hypermethylated in microsatellite-stable cancers, adenomas, and at low levels in normal colonic mucosa from older individuals. Thus, the cluster of genes flanking MLH1 that was specifically methylated in the microsatellite-unstable group of cancers extended across 1.1 Mb. Our results show that coordinate epigenetic silencing extends across a large chromosomal region encompassing MLH1 in microsatellite-unstable colorectal cancers. Simultaneous epigenetic silencing of this cluster of 3p22 genes may contribute to the development or progression of this type of cancer.

Premalignant lesions and gastric cancer: Current understanding.

Over the last two decades there has been a broad paradigm shift in our understanding of gastric cancer (GC) and its premalignant states from gross histological models to increasingly precise molecular descriptions. In this review we reflect upon the historic approaches to describing premalignant lesions and GC, highlight the current molecular landscape and how this could inform future risk assessment prevention strategies.

An algorithm for detection of couch-beam intersection.

A graphical method of avoiding beam blocking by couch supports is described. The technique uses a simplification of the couch cross-section and matrix operations to project the beam into the plane normal to the longitudinal axis of the couch. The algorithm is described, along with a software implementation testing. The application of the software to 3D treatment planning is discussed.

Art27 interacts with GATA4, FOG2 and NKX2.5 and is a novel co-repressor of cardiac genes.

Transcription factors play a crucial role in regulation of cardiac biology. FOG-2 is indispensable in this setting, predominantly functioning through a physical interaction with GATA-4. This study aimed to identify novel co-regulators of FOG-2 to further elaborate on its inhibitory activity on GATA-4. The Art27 transcription factor was identified by a yeast-2-hybrid library screen to be a novel FOG-2 protein partner. Characterisation revealed that Art27 is co-expressed with FOG-2 and GATA-4 throughout cardiac myocyte differentiation and in multiple structures of the adult heart. Art27 physically interacts with GATA-4, FOG-2 and other cardiac transcription factors and by this means, down-regulates their activity on cardiac specific promoters α-myosin heavy chain, atrial natriuretic peptide and B-type natriuretic peptide. Regulation of endogenous cardiac genes by Art27 was shown using microarray analysis of P19CL6-Mlc2v-GFP cardiomyocytes. Together these results suggest that Art27 is a novel transcription factor that is involved in downregulation of cardiac specific genes by physically interacting and inhibiting the activity of crucial transcriptions factors involved in cardiac biology.

A critical role for thioredoxin-interacting protein in diabetes-related impairment of angiogenesis.

Impaired angiogenesis in ischemic tissue is a hallmark of diabetes. Thioredoxin-interacting protein (TXNIP) is an exquisitely glucose-sensitive gene that is overexpressed in diabetes. As TXNIP modulates the activity of the key angiogenic cytokine vascular endothelial growth factor (VEGF), we hypothesized that hyperglycemia-induced dysregulation of TXNIP may play a role in the pathogenesis of impaired angiogenesis in diabetes. In the current study, we report that high glucose-mediated overexpression of TXNIP induces a widespread impairment in endothelial cell (EC) function and survival by reducing VEGF production and sensitivity to VEGF action, findings that are rescued by silencing TXNIP with small interfering RNA. High glucose-induced EC dysfunction was recapitulated in normal glucose conditions by overexpressing either TXNIP or a TXNIP C247S mutant unable to bind thioredoxin, suggesting that TXNIP effects are largely independent of thioredoxin activity. In streptozotocin-induced diabetic mice, TXNIP knockdown to nondiabetic levels rescued diabetes-related impairment of angiogenesis, arteriogenesis, blood flow, and functional recovery in an ischemic hindlimb. These findings were associated with in vivo restoration of VEGF production to nondiabetic levels. These data implicate a critical role for TXNIP in diabetes-related impairment of ischemia-mediated angiogenesis and identify TXNIP as a potential therapeutic target for the vascular complications of diabetes.

Monitoring linear accelerator output constancy using the PTW Linacheck.

The PTW-Linacheck was assessed for its ability to monitor linear accelerator radiation output constancy. The key issues that were considered were the setup for daily output measurements, e.g., requirements for build-up and backscatter material, and the reproducibility and linearity of the device with linear accelerator output. An appropriate measurement setup includes a 10 × 10 cm field at 100 cm FSD, 5 cm backscatter, and no added build-up for 4 MeV electron beams, 1 cm added build-up for 6-16 MeV electron beams and 5 cm added build-up for 6-15 MV photon beams. Using this measurement setup, the dose linearity and short-term reproducibility were acceptable; however, the Linacheck should be recalibrated on a monthly basis to ensure acceptable long-term reproducibility.

Strikingly different angiogenic properties of endothelial progenitor cell subpopulations: insights from a novel human angiogenesis assay.

OBJECTIVES: An endothelial cell (EC)-specific angiogenesis assay was developed to functionally characterize angiogenic properties of 2 distinct putative endothelial progenitor cells (EPCs): early EPCs and late outgrowth endothelial cells (OECs). BACKGROUND: Endothelial progenitor cells promote revascularization of ischemic tissue. However, the nature of different EPCs and their role in angiogenesis remains debated. METHODS: Tubulogenesis was assessed by immunohistochemistry in co-cultures of differentiated ECs (including human umbilical vein, coronary artery, and microvascular ECs) or non-ECs with monolayers of human fibroblasts (MRC5). Using adaptations of the co-culture assay, early EPCs and OECs, isolated from peripheral blood mononuclear cells, were assessed by 3-dimensional immunofluorescence microscopy for their capacity for: 1) independent tubulogenesis; 2) incorporation into pre-existing vascular networks; and 3) paracrine angiogenic effects using transwell cultures. RESULTS: Branched interconnecting EC-specific tubules formed with all differentiated ECs after 72 h. Proangiogenic and antiangiogenic agents modulated tubulogenesis appropriately (vascular endothelial growth factor 10 ng: +142 +/- 13%, 1 microM anti-vascular endothelial growth factor: -44 +/- 7% vs. control, p < 0.001). In contrast, early EPCs, along with nonendothelial cell types, failed to independently form tubules or incorporate into differentiated EC tubules. Nevertheless, early EPCs indirectly augmented tubulogenesis by differentiated ECs even when physically separated by transwells (+115 +/- 4% vs. control; p < 0.001). By contrast, OECs independently formed tubules and incorporated into differentiated EC tubules but exerted no significant paracrine angiogenic effects. CONCLUSIONS: A novel EC-specific tubulogenesis assay highlights strikingly different angiogenic properties of different EPCs: late OECs directly participate in tubulogenesis, whereas early EPCs augment angiogenesis in a paracrine fashion, with implications for optimizing cell therapies for neovascularization.

MLH1 germline epimutations as a factor in hereditary nonpolyposis colorectal cancer.

BACKGROUND & AIMS: Hereditary nonpolyposis colorectal cancer (HNPCC) is caused by heterozygous germline sequence mutations of DNA mismatch repair genes, most frequently MLH1 or MSH2. A novel molecular mechanism for HNPCC has recently been suggested by the finding of individuals with soma-wide monoallelic hypermethylation of the MLH1 gene promoter. In this study, we determined the frequency and role of germline epimutations of MLH1 in HNPCC. METHODS: A cohort of 160 probands from HNPCC families who did not harbor germline sequence mutations in the mismatch repair genes were screened for methylation of the MLH1 and EPM2AIP1 promoters by combined bisulfite and restriction analyses. Allelic expression and family transmission of MLH1 were determined using polymorphisms in intron 4 and the 3' untranslated region. RESULTS: One of 160 individuals had monoallelic MLH1 hypermethylation in peripheral blood, hair follicles, and buccal mucosa, indicative of a soma-wide alteration. Monoallelic transcription of the paternal MLH1 allele was shown using a heterozygous expressed polymorphism within the 3' untranslated region. The hypermethylated allele was maternally transmitted, however, the mother and siblings who inherited the same maternal homologue were unmethylated at MLH1, suggesting the epimutation arose as a de novo event. CONCLUSIONS: Germline MLH1 epimutations are functionally equivalent to an inactivating mutation and produce a clinical phenotype that resembles HNPCC. Inheritance of epimutations is weak, so family history is not a useful guide for screening. Germline epimutations should be suspected in younger individuals without a family history who present with a microsatellite unstable tumor showing loss of MLH1 expression.