Ruthenafuran Complexes Supported by the Bipyridine-Bis(diphenylphosphino)methane Ligand Set: Synthesis and Cytotoxicity Studies.

Mononuclear and dinuclear Ru(II) complexes cis-[Ru(κ2-dppm)(bpy)Cl2] (1), cis-[Ru(κ2-dppe)(bpy)Cl2] (2) and [Ru2(bpy)2(µ-dpam)2(µ-Cl)2](Cl)2 ([3](Cl)2) were prepared from the reactions between cis(Cl), cis(S)-[Ru(bpy)(dmso-S)2Cl2] and diphosphine/diarsine ligands (bpy = 2,2'-bipyridine; dppm = 1,1-bis(diphenylphosphino)methane; dppe = 1,2-bis(diphenylphosphino)ethane; dpam = 1,1-bis(diphenylarsino)methane). While methoxy-substituted ruthenafuran [Ru(bpy)(κ2-dppe)(C^O)]+ ([7]+; C^O = anionic bidentate [C(OMe)CHC(Ph)O]- chelate) was obtained as the only product in the reaction between 2 and phenyl ynone HC≡C(C=O)Ph in MeOH, replacing 2 with 1 led to the formation of both methoxy-substituted ruthenafuran [Ru(bpy)(κ2-dppm)(C^O)]+ ([4]+) and phosphonium-ring-fused bicyclic ruthenafuran [Ru(bpy)(P^C^O)Cl]+ ([5]+; P^C^O = neutral tridentate [(Ph)2PCH2P(Ph)2CCHC(Ph)O] chelate). All of these aforementioned metallafuran complexes were derived from Ru(II)-vinylidene intermediates. The potential applications of these metallafuran complexes as anticancer agents were evaluated by in vitro cytotoxicity studies against cervical carcinoma (HeLa) cancer cell line. All the ruthenafuran complexes were found to be one order of magnitude more cytotoxic than cisplatin, which is one of the metal-based anticancer agents being widely used currently.

Impaired Transmigration of Myeloid-Derived Suppressor Cells across Human Sinusoidal Endothelium Is Associated with Decreased Expression of CD13.

Human monocytic myeloid-derived suppressor cells (MO-MDSCs) within the hepatic compartment suppress inflammation and impair immune surveillance in liver cancer. It is currently not known whether recruitment of MO-MDSCs from blood via hepatic sinusoidal endothelium (HSEC) contributes to their enrichment within the hepatic compartment. We compared the transmigratory potential of MO-MDSCs and monocytes after adhesion to hepatic endothelial monolayers in flow-based assays that mimic in vivo shear stress in the sinusoids. Despite comparable binding to HSEC monolayers, proportionally fewer MO-MDSCs underwent transendothelial migration, indicating that the final steps of extravasation, where actin polymerization plays an important role, are impaired in MO-MDSCs. In this article, we found reduced levels of CD13 on MO-MDSCs, which has recently been reported to control cell motility in monocytes, alongside reduced VLA-4 expression, an integrin predominantly involved in adherence to the apical side of the endothelium. CD13 and VLA-4 blocking and activating Abs were used in flow-based adhesion assays, live-cell imaging of motility, and actin polymerization studies to confirm a role for CD13 in impaired MO-MDSC transmigration. These findings indicate that CD13 significantly contributes to tissue infiltration by MO-MDSCs and monocytes, thereby contributing to the pathogenesis of hepatic inflammation.

The Paddington International Virtual Chromoendoscopy Score in ulcerative colitis exhibits very good inter-rater agreement after computerized module training: a multicenter study across academic and community practice (with video).

BACKGROUND AND AIMS: Electronic virtual chromoendoscopy (EVC) can demonstrate ongoing disease activity in ulcerative colitis (UC), even when Mayo subscores suggest healing. However, applicability of EVC technology outside the expert setting has yet to be determined. METHODS: Fifteen participants across 5 centers reviewed a computerized training module outlining high-definition and EVC (iScan) colonoscopy modes. Interobserver agreement was then tested (Mayo score, Ulcerative Colitis Endoscopic Index of Severity [UCEIS], and the Paddington International Virtual Chromoendoscopy Score [PICaSSO] for UC), using a colonoscopy video library (30 cases reviewed pretraining and 30 post-training). Knowledge sustainability was retested in a second round (42 cases; 9/15 participants), 6 months after training provision. RESULTS: Pretraining intraclass correlation coefficients (ICC) were good for the Mayo endoscopic subscore (ICC, .775), UCEIS scoring erosions/ulcers (ICC, .770), and UCEIS overall (ICC, .786) and for mucosal (ICC, .754) and vascular components of PICaSSO (ICC, .622). For the vascular components of UCEIS, agreement was only moderate (ICC, .429) and did not enhance post-training (ICC, .417); conversely, use of PICaSSO improved post-training (mucosal ICC, .848; vascular, .746). Histologic correlation using the New York Mt. Sinai System was strong for both PICaSSO components (Spearman's ρ for mucosal: .925; vascular, .873; P < .001 for both). Moreover, accuracy in specifically discriminating quiescent from mild histologic strata was strongest for PICaSSO (area under the receiver operating characteristic curve [AUROC] for mucosal, .781; vascular, .715) compared with Mayo (AUROC, .708) and UCEIS (AUROC for UCEIS overall, .705; vascular, .562; bleeding, .645; erosions/ulcers, .696). Inter-rater reliability for PICaSSO was sustained by round 2 participants (round 1 and 2 ICC for mucosal, .873 and .869, respectively; vascular, .715 and .783, respectively), together with histologic correlation (ρ mucosal, .934; vascular, .938; P < .001 for both). CONCLUSIONS: PICaSSO demonstrates good interobserver agreement across all levels of experience, providing excellent correlation with histology. Given the ability to discriminate subtle endoscopic features, PICaSSO may be applied to refine stratified treatment paradigms for UC patients.

Bidirectional transendothelial migration of monocytes across hepatic sinusoidal endothelium shapes monocyte differentiation and regulates the balance between immunity and tolerance in liver.

UNLABELLED: Monocytes are versatile cells that can fulfill proinflammatory and anti-inflammatory functions when recruited to the liver. Recruited monocytes differentiate into tissue macrophages and dendritic cells, which sample antigens and migrate to lymph nodes to elicit T-cell responses. The signals that determine monocyte differentiation and the role of hepatic sinusoidal endothelial cells (HSECs) in this process are poorly understood. HSECs are known to modulate T-cell activation, which led us to investigate whether transendothelial migration of monocytes across HSECs influences their phenotype and function. Subsets of blood-derived monocytes were allowed to transmigrate across human HSECs into a collagen matrix. Most migrated cells remained in the subendothelial matrix, but ~10% underwent spontaneous basal to apical transendothelial migration. The maturation, cytokine secretion, and T-cell stimulatory capacity of reverse transmigrating (RT) and subendothelial (SE) monocytes were compared. SE monocytes were mainly CD16(-) , whereas 75%-80% of RT monocytes were CD16(+) . SE monocytes derived from the CD14(++) CD16(-) subset and exhibited high phagocytic activity, whereas RT monocytes originated from CD14(++) CD16(+) and CD14(+) CD16(++) monocytes, displayed an immature dendritic cell-like phenotype (CD11c(pos) HLA-DR(pos) CD80lo CD86lo ), and expressed higher levels of chemokine (C-C motif) receptor 8. Consistent with a dendritic cell phenotype, RT monocytes secreted inflammatory cytokines and induced antigen-specific CD4(+) T-cell activation. In contrast, SE monocytes suppressed T-cell proliferation and activation and exhibited endotoxin tolerance. Transcriptome analysis underscored the functional differences between SE and RT monocytes. CONCLUSIONS: Migration across HSECs shapes the subsequent fate of monocytes, giving rise to anergic macrophage-like cells in tissue and the release of immunocompetent pre-dendritic cells into the circulation.

Contact-dependent depletion of hydrogen peroxide by catalase is a novel mechanism of myeloid-derived suppressor cell induction operating in human hepatic stellate cells.

Myeloid-derived suppressor cells (MDSC) represent a unique cell population with distinct immunosuppressive properties that have been demonstrated to shape the outcome of malignant diseases. Recently, human hepatic stellate cells (HSC) have been reported to induce monocytic-MDSC from mature CD14(+) monocytes in a contact-dependent manner. We now report a novel and unexpected mechanism by which CD14(+)HLADR(low/-) suppressive cells are induced by catalase-mediated depletion of hydrogen peroxide (H2O2). Incubation of CD14(+) monocytes with catalase led to a significant induction of functional MDSC compared with media alone, and H2O2 levels inversely correlated with MDSC frequency (r = -0.6555, p < 0.05). Catalase was detected in primary HSC and a stromal cell line, and addition of the competitive catalase inhibitor hydroxylamine resulted in a dose-dependent impairment of MDSC induction and concomitant increase of H2O2 levels. The NADPH-oxidase subunit gp91 was significantly increased in catalase-induced MDSC as determined by quantitative PCR outlining the importance of oxidative burst for the induction of MDSC. These findings represent a so far unrecognized link between immunosuppression by MDSC and metabolism. Moreover, this mechanism potentially explains how stromal cells can induce a favorable immunological microenvironment in the context of tissue oxidative stress such as occurs during cancer therapy.

Single-gene association between GATA-2 and autoimmune hepatitis: A novel genetic insight highlighting immunologic pathways to disease.

Background & Aims Autoimmune hepatitis (AIH), an immune-mediated liver disease, originates as a consequence of interacting genetic and environmental risk factors. Treatment remains non-specific and prone to side effects. Deficiencies in regulatory T cell (Treg) function are hypothesized to contribute to the pathogenesis of AIH. Methods We describe an adult patient who presented with AIH in the context of monocytopenia. The patient was characterized by GATA2 gene sequencing, flow cytometry of peripheral blood for leucocyte subsets, ELISA for serum Flt-3 ligand, and immunohistochemistry of liver biopsy tissue. Results Sequencing confirmed a GATA2 mutation. Peripheral Treg were absent in the context of a preserved total T cell count. Immunostaining for the Treg transcription factor FOXP3 was reduced in liver tissue as compared to a control AIH specimen. There were marked deficiencies in multiple antigen-presenting cell subsets and Flt-3 ligand was elevated. These findings are consistent with previous reports of GATA2 dysfunction. Conclusions The association of a GATA2 mutation with AIH is previously unrecognized. GATA2 encodes a hematopoietic cell transcription factor, and mutations may manifest as monocytopenia, dendritic and B cell deficiencies, myelodysplasia, and immunodeficiency. Tregs may be depleted as in this case. Our findings provide support for the role of Tregs in AIH, complement reports of other deficiencies in T cell regulation causing AIH-like syndromes, and support the rationale of attempting to modulate the Treg axis for the therapeutic benefit of AIH patients.

CMV infection of human sinusoidal endothelium regulates hepatic T cell recruitment and activation.

BACKGROUND & AIMS: Human cytomegalovirus infection (HCMV) is associated with an increased morbidity after liver transplantation, by facilitating allograft rejection and accelerating underlying hepatic inflammation. We hypothesized that human hepatic sinusoidal endothelial cells infected with HCMV possess the capacity to modulate allogeneic T cell recruitment and activation, thereby providing a plausible mechanism of how HCMV infection is able to enhance hepatic immune activation. METHODS: Human hepatic sinusoidal endothelial cells were isolated from explanted livers and infected with recombinant endotheliotropic HCMV. We used static and flow-based models to quantify adhesion and transendothelial migration of allogeneic T cell subsets and determine their post-migratory phenotype and function. RESULTS: HCMV infection of primary human hepatic sinusoidal endothelial cells facilitated ICAM-1 and CXCL10-dependent CD4 T cell transendothelial migration under physiological levels of shear stress. Recruited T cells were primarily non-virus-specific CXCR3(hi) effector memory T cells, which demonstrated features of LFA3-dependent Th1 activation after migration, and activated regulatory T cells, which retained a suppressive phenotype following transmigration. CONCLUSIONS: The ability of infected hepatic endothelium to recruit distinct functional CD4 T cell subsets shows how HCMV facilitates hepatic inflammation and immune activation and may simultaneously favor virus persistence.

Optimising risk stratification in primary biliary cirrhosis: AST/platelet ratio index predicts outcome independent of ursodeoxycholic acid response.

BACKGROUND & AIMS: Outcomes in primary biliary cirrhosis (PBC) can be predicted by biochemical response to ursodeoxycholic acid (UDCA). Such stratification inadequately captures cirrhosis/portal hypertension, recognised factors associated with adverse events. METHODS: We evaluated a cohort of PBC patients (n=386) attending the Liver Unit in Birmingham (derivation cohort), seeking to identify risk-variables associated with transplant-free survival independent of UDCA-response. A validation cohort was provided through well-characterised patients attending the Toronto Center for Liver Diseases (n=479) and Jena University Hospital (n=150). RESULTS: On multivariate analysis, factors at diagnosis associated with liver transplant (LT)/death were patient age (HR:1.06; p<0.001), elevated bilirubin (HR:1.27; p<0.001), early-onset cirrhosis (HR:2.40; p<0.001) and baseline AST/platelet ratio index (APRI) (HR:1.95; p<0.001). At 1-year, UDCA biochemical non-response predicted poorer transplant-free survival, and additional factors (multivariate) associated with adverse outcome were age (HR:1.02; p<0.05) and 1-year APRI (HR:1.15; p<0.001). Obtaining a cut-point from our derivation cohort, APRI >0.54 at baseline was predictive of LT/death (adjusted HR: 2.40; p<0.001), and retained statistical significance when applied at 1-year (APRI-r1, adjusted HR:2.75; p<0.001) despite controlling for UDCA-response. Across both cohorts, transplant-free survival was poorer for biochemical-responders with an APRI-r1 >0.54 vs. biochemical-responders with a lower APRI-r1 (p<0.01 and p<0.001, respectively); non-responders with high APRI-r1 had the poorest outcomes (p<0.001 and p<0.001). CONCLUSION: In PBC, elevated APRI is associated with future risk of adverse events, independently and additively of UDCA-response. This cross-centre, robustly validated observation will contribute to ongoing efforts to refine existing risk-stratification tools, as well as direct focus for new therapies in patients with PBC.

Monocyte subsets in human liver disease show distinct phenotypic and functional characteristics.

UNLABELLED: Liver fibrosis is a wound healing response to chronic liver injury and inflammation in which macrophages and infiltrating monocytes participate in both the development and resolution phase. In humans, three monocyte subsets have been identified: the classical CD14++CD16-, intermediate CD14++CD16+, and nonclassical CD14+CD16++ monocytes. We studied the phenotype and function of these monocyte subsets in peripheral blood and liver tissue from patients with chronic inflammatory and fibrotic liver diseases. The frequency of intrahepatic monocytes increased in disease compared with control liver tissue, and in both nondiseased and diseased livers there was a higher frequency of CD14++CD16+ cells with blood. Our data suggest two nonexclusive mechanisms of CD14++CD16+ accumulation in the inflamed liver: (1) recruitment from blood, because more than twice as many CD14++CD16+ monocytes underwent transendothelial migration through hepatic endothelial cells compared with CD14++CD16- cells; and (2) local differentiation from CD14++CD16- classical monocytes in response to transforming growth factor ß and interleukin (IL)-10. Intrahepatic CD14++CD16+ cells expressed both macrophage and dendritic cell markers but showed high levels of phagocytic activity, antigen presentation, and T cell proliferation and secreted proinflammatory (tumor necrosis factor α, IL-6, IL-8, IL-1ß) and profibrogenic cytokines (IL-13), chemokines (CCL1, CCL2, CCL3, CCL5), and growth factors (granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor), consistent with a role in the wound healing response. CONCLUSION: Intermediate CD14++CD16+ monocytes preferentially accumulate in chronically inflamed human liver as a consequence of enhanced recruitment from blood and local differentiation from classical CD14++CD16- monocytes. Their phagocytic potential and ability to secrete inflammatory and profibrogenic cytokines suggests they play an important role in hepatic fibrogenesis.

Non-enzymatic dissociation of human mesenchymal stromal cells improves chemokine-dependent migration and maintains immunosuppressive function.

BACKGROUND AIMS: Human bone marrow-derived mesenchymal stromal cells (MSC) can suppress inflammation; therefore their therapeutic potential is being explored in clinical trials. Poor engraftment of infused MSC limits their therapeutic utility; this may be caused by MSC processing before infusion, in particular the method of their detachment from culture. METHODS: Enzymatic methods of detaching MSC (Accutase and TrypLE) were compared with non-enzymatic methods (Cell Dissociation Buffer [CDB], ethylenediamine tetra-acetic acid and scraping) for their effect on MSC viability, chemokine receptor expression, multi-potency, immunomodulation and chemokine-dependent migration. RESULTS: TrypLE detachment preserved MSC viability and tri-lineage potential compared with non-enzymatic methods; however, this resulted in near complete loss of surface chemokine receptor expression. Of the non-enzymatic methods, CDB detachment preserved the highest viability while retaining significant tri-lineage differentiation potential. Once re-plated, CDB-detached MSC regained their original morphology and reached confluence, unlike with the use of other non-enzymatic methods. Viability was significantly reduced with the use of ethylenediamine tetra-acetic acid and further reduced with the use of cell scraping. Addition of 1% serum during CDB detachment led to higher MSC numbers entering autophagy and increased MSC recovery after re-plating. TrypLE and CDB-detached MSC suppressed CD3(+)CD4(+)CD25(-) T-cell proliferation, although TrypLE-detached MSC exhibited superior suppression at 1:20 ratio. CDB detachment retained surface chemokine receptor expression and consequently increased migration to CCL22, CXCL12 and CCL4, in contrast with TrypLE-detached MSC. CONCLUSIONS: This study demonstrates that non-enzymatic detachment of MSC with the use of CDB minimizes the negative impact on cell viability, multipotency and immunomodulation while retaining chemokine-dependent migration, which may be of importance in MSC delivery and engraftment in sites of injury.

Selective measurement of anti-tTG antibodies in coeliac disease and IgA deficiency: an alternative pathway.

OBJECTIVE: To determine the ability of selective antibody testing to screen for coeliac disease in the presence of IgA deficiency and to define the sensitivity of a pathway using this method. METHOD: All IgA and IgG anti-tTG tests performed at our centre between January 2008 and December 2009, using the Immunocap 250 analyser, were retrospectively reviewed. Positive results were correlated with histology. Results were used to validate our diagnostic pathway. RESULTS: 12 289 consecutive serological tests were reviewed. IgA deficient patients gave either an 'error' reading or very low response on the Immunocap 250 analyser. Subsequent testing of this sub-group demonstrated raised IgG anti-tTG antibodies in those with histologically proven coeliac disease. CONCLUSIONS: Using our antibody screening pathway, which involves the selective use of IgG anti-tTG, sensitivity increased from 87% to 92% in those with IgA deficiency. Adoption of this pathway for coeliac screening would negate the routine screening of immunoglobulin levels, with resultant cost saving.

A method for conducting suppression assays using small numbers of tissue-isolated regulatory T cells.

The suppression assay is a commonly performed assay, measuring the ability of regulatory T cells (Treg) to suppress T cell proliferation. Most frequently, Treg are obtained from the peripheral blood or spleen. Lower yields are obtained by isolation from other tissues, rendering downstream suppression assays challenging to perform. Furthermore, the importance of suppressive subpopulations of Treg favours their isolation by fluorescent-activated cell sorting. Here we describe a method to isolate Treg from human tissues, using colorectal cancer tissue as an example. Treg suppressive capacity was further examined by expression of CCR5 to demonstrate the ability of our method to assess the suppressive capacity of regulatory T cell subsets. To optimise the standard suppression assay to achieve our research aims, the following modifications were made: Treg, isolated from tissues, were sorted directly into a well-plate.Responder T cells, which had been fluorescently-labelled prior to sorting, were added directly into the well-plate.Human Treg Suppression Inspector beads (Miltenyi Biotec Ltd, UK) provided a polyclonal stimulus for proliferation and were added to each well at a bead:lymphocyte ratio of 1:2. This method quantified the suppression of responder T cell proliferation by small numbers of strictly-defined Treg populations isolated from tissues.

Recurrent nonviral liver disease following liver transplantation.

Recurrent disease after liver transplantation is well recognized and remains a potential cause of premature graft loss. The rates of recurrence are difficult to establish because of the lack of consistency in diagnostic criteria and approaches to diagnosis. Owing to the fact that recurrent parenchymal disease may occur in the presence of normal liver tests, those centers that use protocol biopsies will report greater rates of recurrence. It is important to recognize that rates of recurrence vary according to indication and show little correlation with rates of graft loss from recurrent disease. Recurrance rates are greatest for primary sclerosing cholangitis and autoimmune hepatitis, and low reccurrance rates are reported for alcoholic liver disease and recurrent primary biliary cirrhosis. The impact of recurrent nonalcoholic fatty liver disease is not yet clear. Patients and clinicians need to be aware of the possibility of recurrent disease in the differential diagnosis of abnormal liver tests, and management stategies may require alteration to reduce the impact of disease recurrence on outcome. Finally, an understanding of which diseases do recur after transplantation and identification of the risk factors may lead to a better understanding of the pathogenetic mechanisms of these conditions.

The management of patients awaiting liver transplantation.

Since it was first performed in 1963, liver transplantation has become the only effective curative treatment in patients with liver failure. During the interval between being added to the waiting list and receiving a graft, the patient's condition may deteriorate as a result of disease progression or complications of the underlying liver disease. Both may result in death, removal from the waiting list because of futility of the procedure or, a worsened outcome following transplantation. The main aims during this period are to delay or prevent further deterioration in the patient's condition, to optimize their general medical health, to prevent, detect and treat any complications, and to offer treatment for specific conditions to improve the patient's overall outcome following liver transplantation.