miR-192-5p has gained increasing relevance in various diseases, however, its function in acute liver injury is currently unknown. We analysed miR-192-5p serum levels and hepatic miR-192-5p expression in mice after hepatic ischaemia and reperfusion (I/R) as well as in toxic liver injury. On a functional level, miRNA levels were analysed in the different hepatic cell-compartments and in the context of tumour necrosis factor (TNF)-dependent liver cell death. We detected increased serum levels of miR-192-5p after hepatic I/R- and carbon tetrachloride (CCl 4 )-induced liver injury. miR-192-5p levels correlated with the degree of liver damage and the presence of hepatic cell death detected by TUNEL stainings (terminal deoxynucleotidyltransferase-mediated dUTP biotin nick-end labelling stainings). Moreover, expression of miR-192-5p was increased in a hypoxia/reoxygenation (H/R) model of in vitro hepatocyte injury, supporting that the passive release of miR-192-5p represents a surrogate for hepatocyte death in liver injury. In critically ill patients, miR-192-5p levels were elevated selectively in patients with liver injury and closely correlated with the presence of hepatic injury. In contrast with up-regulated miR-192-5p in the serum, we detected a down-regulation of miR-192-5p in both injured mouse and human livers. Deregulation of miR-192-5p in livers was dependent on stimulation with TNF. Functional experiments confirmed a protective effect of down-regulation of miR-192-5p in hepatocytes, suggesting a role of miR-192-5p in limiting liver injury. Finally, we identified Zeb2, an important regulator of cell death, as a potential target gene mediating the function of miR-192-5p . Our data suggest that miR-192-5p is involved in the regulation of liver cell death during acute liver injury and might represent a potent marker of hepatic injury.

Circulating miRNAs (microRNAs) are emerging as promising biomarkers for several pathological conditions, and the aim of this study was to investigate the feasibility of using serum miRNAs as biomarkers for liver pathologies. Real-time qPCR (quantitative PCR)-based TaqMan MicroRNA arrays were first employed to profile miRNAs in serum pools from patients with HCC (hepatocellular carcinoma) or LC (liver cirrhosis) and from healthy controls. Five miRNAs (i.e. miR - 885 - 5p , miR-574-3p , miR-224 , miR -215 and miR - 146a ) that were up-regulated in the HCC and LC serum pools were selected and further quantified using real-time qPCR in patients with HCC, LC, CHB (chronic hepatitis B) or GC (gastric cancer) and in normal controls. The present study revealed that more than 110 miRNA species in the serum samples and wide distribution ranges of serum miRNAs were observed. The levels of miR - 885 - 5p were significantly higher in sera from patients with HCC, LC and CHB than in healthy controls or GC patients. miR - 885 - 5p yielded an AUC [the area under the ROC (receiver operating characteristic) curve] of 0.904 [95% CI (confidence interval), 0.837–0.951, P <0.0001) with 90.53% sensitivity and 79.17% specificity in discriminating liver pathologies from healthy controls, using a cut off value of 1.06 (normalized). No correlations between increased miR - 885 - 5p and liver function parameters [AFP (α-fetoprotein), ALT (alanine aminotransferase), AST (aspartate aminotransferase) and GGT (γ-glutamyl transpeptidase)] were observed in patients with liver pathologies. In summary, miR - 885 - 5p is significantly elevated in the sera of patients with liver pathologies, and our data suggest that serum miRNAs could serve as novel complementary biomarkers for the detection and assessment of liver pathologies.

miRNAs (microRNAs) participate in many diseases including cardiovascular disease. In contrast with our original hypothesis, miRNAs exist in circulating blood and are relatively stable due to binding with other materials. The aim of the present translational study is to establish a method of determining the absolute amount of an miRNA in blood and to determine the potential applications of circulating cell-free miR-1 (microRNA-1) in AMI (acute myocardial infarction). The results revealed that miR-1 is the most abundant miRNA in the heart and is also a heart- and muscle-specific miRNA. In a cardiac cell necrosis model induced by Triton X-100 in vitro , we found that cardiac miR-1 can be released into the culture medium and is stable at least for 24 h. In a rat model of AMI induced by coronary ligation, we found that serum miR-1 is quickly increased after AMI with a peak at 6 h, in which an increase in miR-1 of over 200-fold was demonstrated. The miR-1 level returned to basal levels at 3 days after AMI. Moreover, the serum miR-1 level in rats with AMI had a strong positive correlation with myocardial infarct size. To verify further the relationship between myocardial size and miR-1 level, an IP (ischaemic preconditioning) model was used. The results showed that IP significantly reduced circulating miR-1 levels and myocardial infract size induced by I/R (ischaemia/reperfusion) injury. Finally, the levels of circulating cell-free miR-1 were significantly increased in patients with AMI and had a positive correlation with serum CK-MB (creatine kinase-MB) levels. In conclusion, the results suggest that serum miR-1 could be a novel sensitive diagnostic biomarker for AMI.

This study was conducted to compare the effects of serum from healthy pregnant women and that from pregnant women with pre-eclampsia on oxidative stress in endothelial cells in culture. Human umbilical vein endothelial cells (HUVECs) were incubated with serum from 18 pre-eclamptic, 18 healthy pregnant and 18 healthy non-pregnant women for 24h. The levels of reduced glutathione (GSH) and lipid peroxides (LPOs) were measured in endothelial cell lysates. Measurement of malondialdehyde in combination with 4-hydroxyalkenals has been used as an indicator of LPOs. Serum from healthy pregnant women decreased significantly the LPO content in HUVECs in comparison with serum from pre-eclamptic women and healthy non-pregnant women (30.7±6.6 compared with 39.3±10.9 and 41.0±12.7pmol/mg of protein respectively; P <0.003 and P <0.01 respectively). No differences in GSH content between the three groups (18.3±2.1nmol/mg of protein for healthy pregnant, 19.2±3.3nmol/mg for pre-eclamptic and 18.3±2.0nmol/mg for healthy non-pregnant women) were found. Thus serum from normal pregnant women contains a factor(s) that decreases oxidative stress in human endothelial cells. This mechanism might be altered in pre-eclampsia.

1. The binding of lead to human blood serum, and components of serum, was studied by titration with the addition of Pb(NO 3 ) 2 solution, monitoring the free Pb 2+ concentration with a Pb 2+ electrode, and by equilibrium dialysis. 2. In fresh serum, about 4999 out of 5000 parts of added lead were bound. This suggests that the free Pb 2+ concentration is around 1/5000th of the total lead concentration in the serum of normal subjects, i.e. about 1 × 10 −12 mol/l. 3. About 60% of the binding of lead in serum is abolished by standing in air, by dialysis or by treatment with N -ethylmaleimide. This appears to be due to the presence of thiol compounds, mainly cysteine. The remaining 40% appears to be due to protein, mainly albumin.

1. We studied a brominated thyroid hormone analogue, SKF L-94901, which has the potential to lower serum cholesterol without adverse cardiovascular effects. This compound is about 50% as active as tri-iodothyronine (T 3 ) in liver nuclear receptor binding in vivo but only 1% as active in vitro and has nearly 200 times more enzyme-inducing activity in liver than in heart. Our aim was to examine the interaction of SKF L-94901 with [ 125 I]T 3 binding to the intact nuclei in whole cells, isolated nuclei and nuclear extracts of human HeLa cells and to investigate the binding of this compound to human serum. 2. Relative to thyroxine (T 4 ), the affinity of this compound for T 4 -binding globulin was 0.0035%, for transthyretin 1.66% and for albumin 1.26%. Low affinity for serum proteins, with a relatively high circulating free fraction, could explain why SKF L-94901 is more potent in vivo than in vitro. 3. Human HeLa cell nuclei, isolated after whole-cell incubations, bound [ 125 I]T 3 with high affinity ( K d = 78 ± 8 pmol/l, mean ± sem ), which was displaceable by T 3 analogues in the order Triac {[4-(4-hydroxy-3-iodophenoxy)-3,5-di-iodophenyl]acetic acid} > T 3 > T 4 ≫ reverse T 3 . Similar high-affinity ( K d = 58 ± 6 pmol/l, mean ± sem ) and identical specificity was observed in high-salt (0.4 mol/l KCl) nuclear extracts. In nuclei of whole cells incubated with [ 125 I]T 3 and SKF L-94901, the analogue was 0.8% as potent as T 3 , whereas in experiments with nuclear extract, the analogue was 7.7% as potent as T 3 . Results from incubation of T 3 with isolated nuclei were virtually identical to those obtained with nuclear extracts. 4. These results suggest an extranuclear component may be involved in restricting access of SKF L-94901 to the nucleus. Whether such mechanisms account for observed differences in its effects on different tissues with reduced influence of SKF L-94901 on cardiac tissue remains to be established. 5. We conclude that SKF L-94901 is weakly bound in serum and shows less potent competition for T 3 nuclear binding after incubation of whole cells than after incubation with nuclear extracts or isolated nuclei. This compound may allow further analysis of intracellular mechanisms of thyroid hormone transport and action.

1. The volatile phenols in sera of uraemic patients were analysed by gas-liquid chromatography. The concentrations of p -cresol, 1·17 ± 0·58 (mean ± SD), and phenol, 0·44 ± 0·39 mg/100 ml, were higher than the corresponding values (0·23 ± 0·17 and 0·02 ± 0·03 mg/100ml, respectively) in control subjects. Both compounds were recovered mainly as acid labile conjugates, probably sulphate esters. No unconjugated phenol, o -, m -, or p -cresol or conjugated derivatives of o - or m -cresol were detected. 2. When the standard hospital diet was replaced by an isocaloric low-protein diet, the concentration of p -cresol and urea in serum decreased in the two uraemic patients studied. The serum concentration of phenol was uninfluenced by this change of diet. 3. One female patient was studied during treatment with peritoneal dialysis, which on two out of three occasions appeared to result in decreased concentrations of phenol and p -cresol in serum.

1. The serum of two patients with infections of the upper urinary tract contained a specific factor which inhibited its bactericidal action against the Gram-negative organism causing the infection. 2. The serum of the patients was fractionated by gel filtration and anion-exchange chromatography and pooled fractions were examined for antibactericidal activity. 3. Fractions showing antibactericidal activity appeared to contain only immunoglobulin G and it is suggested that bacterium-specific antibactericidal immunoglobulin G competes with immunoglobulin M, the major bactericidal antibody, for sites on the bacterial surface.