The fractalkine receptor CX3CR1 is involved in liver fibrosis due to chronic hepatitis C infection

BACKGROUND/AIMS: The chemokine receptor CX3CR1 and its specific ligand fractalkine (CX3CL1) are known to modulate inflammatory and fibroproliferative diseases. Here we investigate the role of CX3CR1/fractalkine in HCV-induced liver fibrosis. METHODS: A genotype analysis of CX3CR1 variants was performed in 211 HCV-infected patients. Hepatic expression of CX3CR1 was studied in HCV-infected livers and isolated liver cell populations by RT-PCR and immunohistochemistry. The effects of fractalkine on mRNA expression of profibrogenic genes were determined in isolated hepatic stellate cells (HSC) and CX3CR1 genotypes were related to intrahepatic TIMP-1 mRNA levels. RESULTS: The intrahepatic mRNA expression of CX3CR1 correlates with the stage of HCV-induced liver fibrosis (P=0.03). The CX3CR1 coding variant V249I is associated with advanced liver fibrosis, independent of the T280M variant (P=0.009). CX3CR1 is present on primary HSC and fractalkine leads to a suppression of tissue inhibitor of metalloproteinase (TIMP)-1 mRNA in HSC (P=0.03). Furthermore, CX3CR1 genotypes are associated with TIMP-1 mRNA expression in HCV-infected liver (P=0.03). CONCLUSIONS: The results identify the fractalkine receptor CX3CR1 as susceptibility a gene for hepatic fibrosis in HCV infection. The modulation of TIMP-1 expression by fractalkine and CX3CR1 genotypes provides functional support for the observed genotype-phenotype association.     

Assessment of myocardial injury by serum tumour necrosis factor alpha measurements in acute myocardial infarction

Clinical and experimental data have shown that after acute myocardialinfarction there is a significant release of tumour necrosisfactor alpha. Therefore, an attempt was made to correlate changesin serum tumour necrosis factor alpha concentrations with indicesof infarct extent in patients with acute myocardial infarction. In 50 patients with acute myocardial infarction, blood samplesfor evaluation of tumour necrosis factor alpha and alpha-hydroxybutyrate-dehydrogenasewere collected every 6 h until 120 h after admission. Infarctextent was estimated by clinical parameters such as the occurrenceof heart failure and rhythm disturbances, by enzymatic methodssuch as cumulative release of alpha-hydroxybutyratedehydrogenaseand imaging techniques, by late resting single photon emissiontomography—²⁰¹ thallium scintigraphy — using anextent score and by echocardiography using a wall motion index.The maximum change in serum tumour necrosis factor alpha afterinfarction (TNF) was calculated by subtracting tumour necrosisfactor alpha concentration on admission from peak tumour necrosisfactor alpha concentration. The average peak tumour necrosis factor alpha level was observed84 h after admission (median: 12 pg. ml^–1). Between the72nd and the 96th h no significant changes in tumour necrosisfactor alpha values were observed. Analysis of the data showedthat larger (TNF) values were found to be associated significantlywith signs of heart failure (P=0.003), the presence of rhythmdisturbances (P=0.001), increased enzymatic infarct extent indicatedby cumulative release of alpha-hydroxybutyratedehydrogenase(r=0.74; P<0.001), large myocardial perfusion defects measuredwith ²⁰¹thallium scintigraphy (r=0.80; P<0.001), and a considerablenumber of left ventricular wall motion abnormalities (r=0.57;P<0.001). In conclusion, (TNF) is a reliable method of assessing damageseverity in the myocardium after acute myocardial infarction.As only two blood samples are necessary within 84 h, the methodmay be one of the more convenient for the assessment of infarctsize in clinical practice.     

S100A1 DNA-based Inotropic Therapy Protects Against Proarrhythmogenic Ryanodine Receptor 2 Dysfunction

Restoring expression levels of the EF-hand calcium (Ca²⁺) sensor protein S100A1 has emerged as a key factor in reconstituting normal Ca²⁺ handling in failing myocardium. Improved sarcoplasmic reticulum (SR) function with enhanced Ca²⁺ resequestration appears critical for S100A1''s cyclic adenosine monophosphate-independent inotropic effects but raises concerns about potential diastolic SR Ca²⁺ leakage that might trigger fatal arrhythmias. This study shows for the first time a diminished interaction between S100A1 and ryanodine receptors (RyR2s) in experimental HF. Restoring this link in failing cardiomyocytes, engineered heart tissue and mouse hearts, respectively, by means of adenoviral and adeno-associated viral S100A1 cDNA delivery normalizes diastolic RyR2 function and protects against Ca²⁺- and β-adrenergic receptor-triggered proarrhythmogenic SR Ca²⁺ leakage in vitro and in vivo. S100A1 inhibits diastolic SR Ca²⁺ leakage despite aberrant RyR2 phosphorylation via protein kinase A and calmodulin-dependent kinase II and stoichiometry with accessory modulators such as calmodulin, FKBP12.6 or sorcin. Our findings demonstrate that S100A1 is a regulator of diastolic RyR2 activity and beneficially modulates diastolic RyR2 dysfunction. S100A1 interaction with the RyR2 is sufficient to protect against basal and catecholamine-triggered arrhythmic SR Ca²⁺ leak in HF, combining antiarrhythmic potency with chronic inotropic actions.     

Circulating endothelial progenitor cells are reduced in peripheral vascular complications of type 2 diabetes mellitus

OBJECTIVES: We sought to establish whether a reduction in endothelial progenitor cells (EPCs) has a putative role in peripheral vascular disease (PVD) of type 2 diabetic patients. BACKGROUND: Peripheral vascular disease is a common and severe complication of diabetes mellitus. Impaired collateralization of diabetic vasculopathy has been extensively shown, but causes leading to its pathogenesis are not fully understood. Recently, EPCs have been found to contribute to vascular repair and angiogenesis. Diabetes has been associated with low levels of circulating EPCs, but no data are available in the literature on the relationship between EPCs and PVD in diabetes. METHODS: Flow cytometric analysis was used to quantify circulating progenitor cells (CPCs, CD34+) and EPCs (CD34+KDR+) in 51 patients and 17 control subjects. RESULTS: The CPCs and EPCs from diabetic patients were reduced by 33% and 40%, respectively, compared with healthy subjects (p < 0.001). An inverse correlation was found between the number of EPCs and the values of fasting glucose (r = -0.49, p = 0.006). Peripheral vascular disease was associated with a 47% reduction in EPCs (p < 0.0001) and EPC levels directly correlated with the ankle-brachial index (r = 0.70, p = 0.01). The subgroup of diabetic patients with PVD also had reduced CPCs by 32% (p = 0.037), whereas patients with ischemic foot lesions had the lowest levels of both EPCs and CPCs (p = 0.02). CONCLUSIONS: Our data demonstrate decreased EPC levels in diabetic patients and, for the first time, show that PVD is associated with an extensively low number of EPCs. Depletion of circulating EPCs in diabetic patients may be involved in the pathogenesis of peripheral vascular complications.     

Urease prevents adherence of Helicobacter pylori to Kato III gastric epithelial cells

The role of urease in Helicobacter pylori adherence to and internalization by Kato III cells was investigated. Kato III cells were incubated with wild-type strains (N6 or P1), with isogenic mutants lacking urease (N6ureB::TnKm or P1ureA::TnMax5) or producing the inactive apoprotein (N6ureG::TnKm), and with urease-positive clones recovered after complementation of N6ureB::TnKm with ureAB. Bacteria were stained with the green fluorescent dye PKH2, and the bacteria load of cells was analyzed by flow cytometry. With mutants lacking urease, the bacteria load was considerably increased, in comparison with the corresponding parental strains (P<.001). With clone K2(3), producing larger amounts of urease than N6, a significant reduction of bacteria load was observed, in comparison with the wild type (P<.001). N6ureG::TnKm showed adherence characteristics similar to those of N6. The role of urease in internalization was not clear. Thus, urease significantly inhibits H. pylori adherence to Kato III cells by a mechanism largely independent of enzymatic activity.     

Investigation of the genetic interaction between BDNF and DRD3 genes in suicidical behaviour in psychiatric disorders

Objectives. Suicide is a serious public health concern, and it is partly genetic. The brain-derived neurotrophic factor (BDNF) gene has been a strong candidate in genetic studies of suicide (Dwivedi et al., Arch Gen Psychiatry 2010;60:804–815; Zai et al., Prog Neuropsychopharmacol Biol Psychiatry 2012;34:1412–1418) and BDNF regulates the expression of the dopamine D₃ receptor. Objective. We examined the role of the BDNF and DRD3 genes in suicide. Methods. We analysed four tag single-nucleotide polymorphisms (SNPs) in BDNF and 15 SNPs in the D₃ receptor gene DRD3 for possible association with suicide attempt history in our Canadian sample of Schizophrenia (SCZ) patients of European ancestry (N = 188). Results. In this sample, we found a possible interaction between the BDNF Val66Met and DRD3 Ser9Gly SNPs in increasing the risk of suicide attempt(s) in our SCZ sample. Specifically, a larger proportion of SCZ patients who were carrying at least one copy of the minor allele at each of the Val66Met and Ser9Gly functional markers have attempted suicides compared to patients with other genotypes (Bonferroni P < 0.05). However, we could not replicate this finding in samples from other psychiatric populations. Conclusions. Taken together, the results from the present study suggest that an interaction between BDNF and DRD3 may not play a major role in the risk for suicide attempt, though further studies, especially in SCZ, are required.