miR-539 as a key negative regulator of the MEK pathway in myocardial infarction

BACKGROUND

Myocardial infarction is one of the most common causes of death, and the number of individuals at risk is increasing. A rapid and accurate differential diagnosis of myocardial infarction is crucial for timely interventions and for improvement of the prognosis. However, it is difficult to achieve using current methods. To better manage this condition, improved tools for risk prediction, including more accurate biomarkers, are needed.

METHODS

We studied the expression of microRNA-539 (miR-539) and of MEK protein using a rat model of myocardial infarction.

RESULTS

The results of our experiments demonstrated an increase in the expression of miR-539 and a decrease in the expression of MEK. Furthermore, we observed that miR-539 inhibited the expression of MEK through targeting of the 3'UTR of MEK; this led not only to suppressed proliferation but also to apoptosis and autophagy of H9C2 cells.

CONCLUSION

Overexpression of miR-539 plays a role in the degree of myocardial infarction. On the basis of our results, we conclude that miR-539 may be a potential therapeutic target for myocardial infarction.

Identification of STOML2 as a putative novel asthma risk gene associated with IL6R

BACKGROUND

Functional variants in the interleukin-6 receptor gene (IL6R) are associated with asthma risk. We hypothesized that genes co-expressed with IL6R might also be regulated by genetic polymorphisms that are associated with asthma risk. The aim of this study was to identify such genes.

METHODS

To identify genes whose expression was correlated with that of IL6R, we analyzed gene expression levels generated for 373 human lymphoblastoid cell lines by the Geuvadis consortium and for 38 hematopoietic cell types by the Differentiation Map Portal (DMAP) project. Genes correlated with IL6R were then screened for nearby single nucleotide polymorphisms (SNPs) that were significantly associated with both variation in gene expression levels (eSNPs) and asthma risk.

RESULTS

We identified 90 genes with expression levels correlated with those of IL6R and that also had a nearby eSNP associated with disease risk in a published asthma GWAS (N = 20 776). For 16 (18%) genes, the association between the eSNP and asthma risk replicated with the same direction of effect in a further independent published asthma GWAS (N = 27 378). Among the top replicated associations (FDR < 0.05) were eSNPs for four known (IL18R1, IL18RAP, BCL6, and STAT6) and one putative novel asthma risk gene, stomatin-like protein 2 (STOML2). The expression of STOML2 was negatively correlated with IL6R, while eSNPs that increased the expression of STOML2 were associated with an increased asthma risk.

CONCLUSION

The expression of STOML2, a gene that plays a key role in mitochondrial function and T-cell activation, is associated with both IL-6 signaling and asthma risk.

Toll-like receptor 2 ligand, lipoteichoic acid is inhibitory against infectious laryngotracheitis virus infection in vitro and in vivo

Lipoteichoic acid (LTA) is one of the pathogen associated molecular patterns (PAMPs) that activates toll-like receptor (TLR)2-cluster of differentiation (CD)14 signalling pathway. This recognition elicits antiviral responses that have been recorded against viruses of mammals although such responses have not been characterized adequately against avian viruses. In this investigation, we characterized the LTA induced antiviral responses against infectious laryntotracheitis virus (ILTV) infection in vitro and in vivo. We found that LTA is capable of up regulating mRNA expression of innate proteins in macrophages such as MyD88, iNOS and IL-1β and reduces the ILTV plaques in vitro. Similarly, we found that LTA treatment of embryonic day 18 (ED18) eggs can lead to the antiviral response against pre-hatch ILTV infection in vivo and is associated with expansion of macrophage populations and expression of IL-1β and MyD88 in the lung. The data highlight that LTA can be a potential innate immune stimulant that can be used against ILTV infection in chickens.

Genome-wide association study of body mass index in 23 000 individuals with and without asthma

BACKGROUND

Both asthma and obesity are complex disorders that are influenced by environmental and genetic factors. Shared genetic factors between asthma and obesity have been proposed to partly explain epidemiological findings of co-morbidity between these conditions.

OBJECTIVE

To identify genetic variants that are associated with body mass index (BMI) in asthmatic children and adults, and to evaluate if there are differences between the genetics of BMI in asthmatics and healthy individuals.

METHODS

In total, 19 studies contributed with genome-wide analysis study (GWAS) data from more than 23 000 individuals with predominantly European descent, of whom 8165 are asthmatics.

RESULTS

We report associations between several DENND1B variants (P = 2.2 × 10(-7) for rs4915551) on chromosome 1q31 and BMI from a meta-analysis of GWAS data using 2691 asthmatic children (screening data). The top DENND1B single nucleotide polymorphisms(SNPs) were next evaluated in seven independent replication data sets comprising 2014 asthmatics, and rs4915551 was nominally replicated (P < 0.05) in two of the seven studies and of borderline significance in one (P = 0.059). However, strong evidence of effect heterogeneity was observed and overall, the association between rs4915551 and BMI was not significant in the total replication data set, P = 0.71. Using a random effects model, BMI was overall estimated to increase by 0.30 kg/m(2) (P = 0.01 for combined screening and replication data sets, N = 4705) per additional G allele of this DENND1BSNP. FTO was confirmed as an important gene for adult and childhood BMI regardless of asthma status.

CONCLUSIONS AND CLINICAL RELEVANCE

DENND1B was recently identified as an asthma susceptibility gene in a GWAS on children, and here, we find evidence that DENND1B variants may also be associated with BMI in asthmatic children. However, the association was overall not replicated in the independent data sets and the heterogeneous effect of DENND1B points to complex associations with the studied diseases that deserve further study.

Gastro-oesophageal reflux and respiratory symptoms in Busselton adults: the effects of bodyweight and sleep apnoea

BACKGROUND/AIM

Respiratory symptoms and gastro-oesophageal reflux disease (GORD) are common within the general population. Although a number of epidemiological studies have addressed their relationship, none has investigated the confounding effects of body mass index (BMI) and obstructive sleep apnoea (OSA), both of which are associated with reflux.

METHODS

Men and women (2700) from the 2005-2007 cross-sectional Busselton health survey were included. Questionnaire data included demography, information on general health, asthma, cough, wheeze, dyspnoea and reflux symptoms (never, monthly or less often and weekly or more often). BMI, risk of OSA (Berlin questionnaire definition), spirometry and airway hyperresponsiveness (AHR) were recorded. The effects of BMI and OSA on the relationship between respiratory and reflux symptoms were examined using logistic regression models, expressed as adjusted odds ratios for risk of respiratory symptoms by reflux symptom category.

RESULTS

Fifty per cent had reflux symptoms (5-10% weekly or more often). Reflux symptoms had strong positive, dose-related associations with cough/phlegm, breathlessness, chest tightness and wheeze in the last 12 months (P < 0.001), but were not related to diagnosed asthma or AHR. Twenty-three per cent were at high risk of OSA and 63% had a BMI of >25 (22% > 30). Increased weight or high risk of OSA did not affect the relationship between respiratory symptoms and reflux symptoms.

CONCLUSION

The relationship between reflux and respiratory symptoms was independent of BMI, high risk of OSA or AHR. These findings suggest that reflux contributes directly to respiratory symptoms.

Temporal alterations and cellular mechanisms of transmural repolarization during progression of mouse cardiac hypertrophy and failure

AIM

The remodelling of transmural dispersion of repolarization (TDR) in human heart failure (HF) and in different animal models of cardiac hypertrophy or HF remains a controversial topic. We hypothesize that TDR may exhibit temporal alterations, depending on the stage of the disease.

METHODS

We systematically investigated the temporal alterations of TDR during the development of cardiac hypertrophy and HF in the mouse pressure-overload model using electrophysiological and molecular biology techniques.

RESULTS

A progressive prolongation of QT interval and changes in the amplitude of the J wave at 2, 5, 9 and 13 weeks were found in anesthetized aorta-banded mice. Action potential duration (APD) at 90% repolarization (APD90) in subendocardial myocytes of the left ventricular free wall remained unchanged at the hypertrophic stage (2 and 5 weeks), but was significantly prolonged in HF mice at 9 and 13 weeks. However, APD90 in subepicardial myocytes exhibited a significant prolongation at 2 weeks and did not progressively extend from 2 weeks to 13 weeks in banded mice. Thus, non-parallel prolongation of APD in subendocardial and subepicardial myocytes led to a reduction in TDR at hypertrophic stage and an amplification of TDR at HF stage. Further experiments revealed that asynchronous down-regulation of voltage-dependent potassium currents (I(to,f), I(K,slow) and I(ss)) and L-type calcium currents (I(Ca-L)) in subendocardial and subepicardial myocytes may contribute to the dynamic remodelling of transmural APD.

CONCLUSION

The two distinct TDR modes were revealed during the progression of mouse cardiac hypertrophy and failure, indicating that the remodelling of TDR depends on the stage of the disease.

Genome-wide association study to identify genetic determinants of severe asthma

BACKGROUND

The genetic basis for developing asthma has been extensively studied. However, association studies to date have mostly focused on mild to moderate disease and genetic risk factors for severe asthma remain unclear.

OBJECTIVE

To identify common genetic variants affecting susceptibility to severe asthma.

METHODS

A genome-wide association study was undertaken in 933 European ancestry individuals with severe asthma based on Global Initiative for Asthma (GINA) criteria 3 or above and 3346 clean controls. After standard quality control measures, the association of 480 889 genotyped single nucleotide polymorphisms (SNPs) was tested. To improve the resolution of the association signals identified, non-genotyped SNPs were imputed in these regions using a dense reference panel of SNP genotypes from the 1000 Genomes Project. Then replication of SNPs of interest was undertaken in a further 231 cases and 1345 controls and a meta-analysis was performed to combine the results across studies.

RESULTS

An association was confirmed in subjects with severe asthma of loci previously identified for association with mild to moderate asthma. The strongest evidence was seen for the ORMDL3/GSDMB locus on chromosome 17q12-21 (rs4794820, p=1.03×10((-8)) following meta-analysis) meeting genome-wide significance. Strong evidence was also found for the IL1RL1/IL18R1 locus on 2q12 (rs9807989, p=5.59×10((-8)) following meta-analysis) just below this threshold. No novel loci for susceptibility to severe asthma met strict criteria for genome-wide significance.

CONCLUSIONS

The largest genome-wide association study of severe asthma to date was carried out and strong evidence found for the association of two previously identified asthma susceptibility loci in patients with severe disease. A number of novel regions with suggestive evidence were also identified warranting further study.

Using an abnormal increase in postexercise systolic blood pressure to diagnose coronary artery disease in gerontal patients

Data from 66 patients ≥ 60 years old with suspected coronary artery disease (CAD) were studied to determine the diagnostic value of an abnormal increase in postexercise systolic blood pressure (SBP) for detecting CAD in gerontal patients. Treadmill exercise testing (TET) and selective coronary angiography (CAG) were carried out and SBP was measured pre-TET and at each minute during a 6-min post-TET recovery phase. Abnormal increase in postexercise SBP was defined as a higher SBP compared with that measured earlier during the 6-min post-TET period. An abnormal increase of ≥ 7 mmHg in postexercise SBP had a statistically significantly better specificity, and also showed higher sensitivity and accuracy, than ST-segment depression ≥ 1 mV in identifying gerontal patients with CAD. The combination of ST-segment depression and abnormal SBP resulted in further improvement of the specificity for detecting CAD. It is concluded that measurement of abnormal increase in postexercise SBP may be a sensitive indicator of gerontal CAD.

Pictorial review of mucopolysaccharidosis with emphasis on MRI features of brain and spine

Mucopolysaccharidosis (MPS) is an inherited metabolic disorder of childhood, characterised by progressive multisystem involvement predominantly affecting the skeletal system leading to skeletal dysplasia. Mental retardation, neuropathy and cardiomyopathy may occur in the most severely affected patients, leading to progressive disability and death in their early third to fourth decades. The purpose of this paper is to illustrate the typical imaging features of different types of MPS, in particular the MR features of the brain and spine in MPS, which are expected to be encountered by radiologists more frequently in their clinical practice as a result of prolonged life expectancy for those with MPS with recent advances in therapeutic interventions. The treatment options and outcomes for MPS patients are also briefly discussed.

Multimedia manuscript: laparoscopic resection of hepatocellular carcinoma at segment 7: the posterior approach to anatomic resection

BACKGROUND

Open anatomical liver resections remain one of the most effective treatments of hepatocellular carcinoma (HCC) and results in better recurrence-free and overall survival compared to nonanatomical resections [1]. On the other hand, laparoscopic hepatectomies for HCC have recently emerged with the benefits of reduced blood loss, shorter hospital stay, and less severe wound pain [2, 3]. Classically, liver lesions considered suitable for laparoscopic resection were those small tumors (<4 cm) located over the anterior and left lateral segments [3]. However, we would like to expand the current indications and here we present our techniques of laparoscopic anatomical resection for a HCC that was located at right posteriosuperior segment 7.

METHODS

Our patient was a 60-year-old gentleman who had Child's A hepatitis B cirrhosis and was on entecavir. During a follow-up CT scan, a 2.6-cm segment 7 lesion with early arterial enhancement and contrast washout was noted and was subsequently confirmed with arteriogram. α-Fetoprotein was 3 ng/ml (normal < 20 ng/ml). The video demonstrates a posterior approach to laparoscopic resection of segment 7.

RESULTS

Operative time was 510 min. Blood loss was 800 ml and no perioperative transfusion was required. Postoperative recovery was uneventful and only simple oral analgesics were required for pain control. He was discharged on postoperative day 6. Histology showed a moderately differentiated hepatocellular carcinoma and all resection margins were clear. Subsequent follow-up CT scan 6 months after the operation showed no evidence of recurrence and α-fetoprotein level was normal.

CONCLUSIONS

Laparoscopic hepatectomy for HCC over the right posterior segment of the liver is feasible in selected patients with favorable results in terms of wound size, postoperative recovery, and hospital stay. Maximal liver conservation was achieved in performing oncologic anatomical resection of segment 7 instead of a posterior sectionectomy. On the other hand, a posterior approach was recommended because it allowed early intrahepatic control of pedicles and identification of the right hepatic vein to guide parenchymal transection along the intersegmental plane.

Patterns of airway disease and the clinical diagnosis of asthma in the Busselton population

The aim of this study was to examine how objective measures related to lung function cluster in the general population and how the patterns relate to asthma and bronchitis as diagnosed by a doctor (DDA and DDB, respectively). A cross-sectional survey of an age-stratified random general population sample of 1,969 adults from the electoral register of Busselton (Australia) was performed in 2005-2007. Respiratory symptoms, DDA ever, DDB ever, recent wheezing and smoking history, together with anthropometric measurements, forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC), methacholine challenge or bronchodilator response, exhaled nitric oxide (eNO), skin-prick tests to common allergens, and blood eosinophil and neutrophil counts were studied. Cluster analysis (variables sex, age, atopy, FEV₁ % predicted, FEV₁/FVC, airway hyperresponsiveness, eNO, log eosinphil count, log neutrophil count and body mass index) was used to identify phenotypic patterns. Seven clusters (subjects with DDA and DDB, respectively) were identified: normal males (n=467; 7 and 13%), normal females (n=477; 12 and 18%), obese females (n=250; 16 and 28%), atopic younger adults (n=330; 21 and 17%), atopic adults with high eNO (n=130; 30 and 25%), atopic males with reduced FEV₁ (n=103; 33 and 32%) and atopic adults with bronchial hyperreactivity (n=212; 40 and 26%). The clinical diagnosis of asthma (ever) and bronchitis (ever) is not specific for any of the clustering patterns of airway abnormality.

Biochemical and molecular characterization of tyrosine hydroxylase deficiency in Hong Kong Chinese

Tyrosine hydroxylase deficiency is a rare neurotransmitter disorder affecting the rate-limiting step in catecholamine biosynthesis. There are about 40 cases reported worldwide. Here, we report the biochemical and molecular findings of eight unrelated Chinese patients with tyrosine hydroxylase deficiency. We have identified eight novel mutations with 5 missense, 2 nonsense and 1 splicing mutations in the TH gene, namely p.R153X, p.R169X, p.G294R, p.G315S, p.A385V, p.I394T, p.G408R, and c.1163+5G>C. The mutations of the TH gene in Chinese are heterogeneous.