Vascular Disease and Risk Stratification for Ischemic Stroke and All-Cause Death in Heart Failure Patients without Diagnosed Atrial Fibrillation: A Nationwide Cohort Study

Background

Stroke and mortality risk among heart failure patients previously diagnosed with different manifestations of vascular disease is poorly described. We conducted an observational study to evaluate the stroke and mortality risk among heart failure patients without diagnosed atrial fibrillation and with peripheral artery disease (PAD) or prior myocardial infarction (MI).

Methods

Population-based cohort study of patients diagnosed with incident heart failure during 2000–2012 and without atrial fibrillation, identified by record linkage between nationwide registries in Denmark. Hazard rate ratios of ischemic stroke and all-cause death after 1 year of follow-up were used to compare patients with either: a PAD diagnosis; a prior MI diagnosis; or no vascular disease.

Results

39,357 heart failure patients were included. When compared to heart failure patients with no vascular disease, PAD was associated with a higher 1-year rate of ischemic stroke (adjusted hazard rate ratio [HR]: 1.34, 95% confidence interval [CI]: 1.08–1.65) and all-cause death (adjusted HR: 1.47, 95% CI: 1.35–1.59), whereas prior MI was not (adjusted HR: 1.00, 95% CI: 0.86–1.15 and 0.94, 95% CI: 0.89–1.00, for ischemic stroke and all-cause death, respectively). When comparing patients with PAD to patients with prior MI, PAD was associated with a higher rate of both outcomes.

Conclusions

Among incident heart failure patients without diagnosed atrial fibrillation, a previous diagnosis of PAD was associated with a significantly higher rate of the ischemic stroke and all-cause death compared to patients with no vascular disease or prior MI. Prevention strategies may be particularly relevant among HF patients with PAD.     

Carboxylesterase 1 Gene Duplication and mRNA Expression in Adipose Tissue Are Linked to Obesity and Metabolic Function

Context and Aims

Carboxylesterase 1 (CES1) appears to play an important role in the control of the metabolism of triglycerides and cholesterol in adipocytes and other cell types including hepatocytes. Therefore, it is relevant to gain insights into the genetic versus non-genetic mechanisms involved in the control of CES1 mRNA expression. Here, we investigated CES1 mRNA expression level in adipose tissue and its association with measures of adiposity and metabolic function in a population of elderly twins. Furthermore, the heritability of CES1 mRNA expression level in adipose tissue and the effect of CES1 gene duplication were assessed.

Methodology

A total of 295 monozygotic and dizygotic twin subjects (62–83 years) with (n = 48) or without (n = 247) type 2 diabetes mellitus were enrolled in the study. They were subjected to a standard oral glucose tolerance test and excision of abdominal subcutaneous fat biopsies during the fasting state. Levels of CES1 mRNA and copy number of the gene were assessed by quantitative PCR.

Results

CES1 mRNA expression level in adipose tissue was positively associated with body-mass index (P<0.001), homeostasis model assessment-insulin resistance (P = 0.003) and level of fasting glucose (P = 0.002), insulin (P = 0.006), and triglycerides (P = 0.003). The heritability for the expression of CES1 mRNA in adipose tissue was high. CES1 gene duplication was positively associated with insulin sensitivity (P = 0.05) as well as glucose tolerance (P = 0.03) and negatively associated with homeostasis model assessment-insulin resistance (P = 0.02). Duplication of CES1 was not linked to mRNA level of this gene (P = 0.63).

Conclusion

CES1 mRNA in adipose tissue appears to be under strong genetic control and was associated with measures of metabolic function raising the possibility of a potential role of this enzyme in the development of type 2 diabetes mellitus. Further studies are needed to understand the potential effect of CES1 gene duplication on adipocyte and whole-body metabolic functions.     

Characterization of a multifunctional inositol phosphate kinase from rice and barley belonging to the ATP-grasp superfamily

OsIpk and HvIpk, inositol phosphate kinases, were cloned from rice (Oryza sativa L. var. indica, IR64) and barley (Hordeum vulgare) respectively. Sequence alignment showed that they belong to the ATP-grasp family, which includes inositol 1,3,4-trisphosphate 5/6-kinase from humans and Arabidopsis. Residues that are binding sites for ATP and coordinate magnesium in absence or presence of inositol phosphate are conserved and in total 23 residues are invariant among the twelve aligned inositol phosphate kinases. The genes were heterologously expressed in Escherichia coli and kinase activity assays with 17 different isomers of inositol mono-/di-/tri-/tetra-/pentaphosphate as well as phytate were performed. The strongest activity for both kinases was observed with Ins(3,4,5,6)P(4), which candidates as the primary substrate for these kinases in plants. Several species-specific differences between the two recombinant Ipks were observed. Rice OsIpk showed detectable kinase activity towards eight different substrates, whereas barley HvIpk showed kinase activity with all the substrates including inositol mono- and bisphosphates. HvIpk showed 3-kinase activity towards the Ins(1,4,5)P(3) substrate and it also interconverted the two substrates Ins(1,3,4,5)P(4) and Ins(1,3,4,6)P(4) by isomerase activity, which was not observed for the rice homologue. Both OsIpk and HvIpk had no detectable 2-kinase activity. Furthermore, the two Ipks showed phosphatase activity towards several inositol phosphates. Expression analysis by RT-PCR demonstrated that the Ipk gene was equally expressed in different tissues and developmental stages. Taken together, these results show that the Ipk kinase plays a significant role in the inositol phosphate interacting network in plants.     

Efficient delivery of T cell epitopes to APC by use of MHC class II-specific Troybodies

A major objective in vaccine development is the design of reagents that give strong, specific T cell responses. We have constructed a series of rAb with specificity for MHC class II (I-E). Each has one of four different class II-restricted T cell epitopes genetically introduced into the first C domain of the H chain. These four epitopes are: 91-101 lambda2(315), which is presented by I-E(d); 110-120 hemagglutinin (I-E(d)); 323-339 OVA (I-A(d)); and 46-61 hen egg lysozyme (I-A(k)). We denote such APC-specific, epitope-containing Ab "Troybodies." When mixed with APC, all four class II-specific Troybodies were approximately 1,000 times more efficient at inducing specific T cell activation in vitro compared with nontargeting peptide Ab. Furthermore, they were 1,000-10,000 times more efficient than synthetic peptide or native protein. Conventional intracellular processing of the Troybodies was required to load the epitopes onto MHC class II. Different types of professional APC, such as purified B cells, dendritic cells, and macrophages, were equally efficient at processing and presenting the Troybodies. In vivo, class II-specific Troybodies were at least 100 times more efficient at targeting APC and activating TCR-transgenic T cells than were the nontargeting peptide Ab. Furthermore, they were 100-100,000 times more efficient than synthetic peptide or native protein. The study shows that class II-specific Troybodies can deliver a variety of T cell epitopes to professional APC for efficient presentation, in vitro as well as in vivo. Thus, Troybodies may be useful as tools in vaccine development.     

Protein kinase C activity in renal microvillus membranes

Protein kinase C activity was found in rabbit renal microvillus membrane vesicles. C-kinase activity was assayed by examining H1 histone phosphorylation using microvillus membrane vesicles dispersed with Triton X. Calcium-activated protein kinase activity was only demonstrable in the presence of phosphatidylserine (PS). With PS (15 micrograms/ml) the Ka for activation by calcium was 1.04 microM. This was reduced to 0.38 microM by addition of diolein (3.75 micrograms/ml). These activations were dose-dependent and their combined synergistic activation could be reproduced by the combination of PS (15 micrograms/ml) and the phorbol ester, TPA (1.17 ng/ml). During microvillus membrane purification, protein kinase C activity enriched 5-fold relative to its activity in the homogenates. The activity was not due to trapped cytosol or adventitious association with microvillus membranes during homogenization. During further purification on sucrose gradients, the C-kinase activity coenriched with brush border and not with basolateral enzyme markers. We conclude that protein kinase C is a normal component of the renal microvillus membrane.     

Systemic Induction of Salicylic Acid Accumulation in Cucumber after Inoculation with Pseudomonas syringae pv syringae

Inoculation of one true leaf of cucumber (Cucumis sativus L.) plants with Pseudomonas syringae pathovar syringae results in the systemic appearance of salicylic acid in the phloem exudates from petioles above, below, and at the site of inoculation. Analysis of phloem exudates from the petioles of leaves 1 and 2 demonstrated that the earliest increases in salicylic acid occurred 8 hours after inoculation of leaf 1 in leaf 1 and 12 hours after inoculation of leaf 1 in leaf 2. Detaching leaf 1 at intervals after inoculation demonstrated that leaf 1 must remain attached for only 4 hours after inoculation to result in the systemic accumulation of salicylic acid. Because the levels of salicylic acid in phloem exudates from leaf 1 did not increase to detectable levels until at least 8 hours after inoculation with P. s. pathovar syringae, the induction of increased levels of salicylic acid throughout the plant are presumably the result of another chemical signal generated from leaf 1 within 4 hours after inoculation. Injection of salicylic acid into tissues at concentrations found in the exudates induced resistance to disease and increased peroxidase activity. Our results support a role for salicylic acid as an endogenous inducer of resistance, but our data also suggest that salicylic acid is not the primary systemic signal of induced resistance in cucumber.     

Metabolomics analysis of the Lolium perenne–Neotyphodium lolii symbiosis: more than just alkaloids?

Above ground plant parts of Lolium perenne often harbour endophytic Neotyphodium lolii fungi. These occur both naturally and commercially, as variant strains are introduced to modify the grass metabolic profile. They reside in the apoplastic spaces and rarely cause visible symptoms of infection. The vast majority of literature has focussed on the biosynthesis, accumulation, and ecological relevance of a limited number of alkaloids produced by N. lolii which have been shown to negatively affect insect pests and vertebrate herbivores. Much less is known about the effects of other metabolites in these interactions or the role of resource supply on metabolic profiles, nor critically on the metabolic consequences of differences in the amount (concentration) of endophyte present. Here, we provide a synthesis of some of our recently published studies on effects of resource supply (nitrogen, carbohydrates) on concentrations of endophytes and endophyte specific metabolites in the L. perenne–N. lolii association. We present results of both quantitative PCR and targeted metabolomics studies, using contrasting endophyte strains in two perennial ryegrass cultivars. We also present and discuss a hypothetical schematic representation of possible links between plant and fungal metabolic networks. A multiple regression analysis of numerical insect responses and metabolic profiles indicates that effects of endophyte infection on insect population sizes could be predicted by concentrations of a range of metabolites other than alkaloids and depended on insect species, fungal strain, and nitrogen supply.     

Beta-Lactamase Producing Escherichia coli Isolates in Imported and Locally Produced Chicken Meat from Ghana

The use of antibiotics in food animals is of public health concern, because resistant zoonotic pathogens can be transmitted to humans. Furthermore, global trade with food may rapidly spread multi-resistant pathogens between countries and even continents. The purpose of the study was to investigate whether imported chicken meat and meat from locally reared chicken are potential sources for human exposure to multi resistant Escherichia coli isolates. 188 samples from imported and locally produced chicken meat were sampled and analyzed. 153 bacteria isolates were successfully cultured and identified as E. coli using MALDI-ToF. Of these 109 isolates were from meat whereas the remaining 44 were isolated from the cloaca of locally reared live chickens. Antimicrobial susceptibility test was done on the identified E. coli isolates. Additionally, beta-lactamases production (ESBL and/or AmpC) were phenotypically confirmed on all isolates showing resistance to cefpodoxime. Beta-lactamase producing (BLP) E. coli meat isolates were further genotyped. Antimicrobial resistance to four antibiotic markers with highest resistance was detected more frequently in isolates from local chickens compared to imported chickens (tetracycline 88.9% vs. 57.5%, sulphonamide 75.0% vs. 46.6%, ampicillin 69.4% vs. 61.6% and trimethoprim 66.7% vs. 38.4%). Beta-lactamase production was found in 29 E. coli meat isolates, with 56.9% of them being multiple drug resistant (≥ 3). The predominant phylogroup identified was B1 followed by A and D, with similar distribution among the isolates from meat of locally reared chickens and imported chickens. Beta-lactamase producing genotype bla _CTX-M-15 (50%; 10/20) was the most frequently drug resistant gene detected. More BLP E. coli isolates were found in imported chicken meat compared to locally reared chickens, demonstrating that these isolates may be spreading through food trade. In conclusion, both imported and locally produced chicken meats are potential sources for human exposure to BLP E. coli.     

Signal sequence mutations that alter coupling of secretion and translation of an Escherichia coli outer membrane protein.

The lamB701-708 signal sequence mutation reduces expression of LamB, an outer membrane protein of Escherichia coli. To investigate the possibility that synthesis and export of LamB are coupled, as suggested by the expression defect of the lamB701-708 mutation, we isolated intragenic suppressors of the lamB701-708 mutation. The expression defect imposed by the lamB701-708 mutation is suppressed by an export-defective signal sequence mutation, suggesting that translation and export are coupled. The additional observation that not all export-defective signal sequence mutations suppressed the lamB701-708 expression defect suggests that translational arrest can be uncoupled from export.