Atherosclerotic cardiovascular disease landscape in Singapore.

Cardiovascular disease (CVD) is the leading cause of death worldwide, accounting for over one-third of all deaths in Singapore. An analysis of age-standardized mortality rates (ASMR) for CVD in Singapore revealed a deceleration in the initial rapid decline in ASMR. A decrease in smoking prevalence may have contributed to the initial rapid decline in ASMR. Furthermore, other major risk factors, such as diabetes mellitus, hypertension, elevated low-density lipoprotein levels, and obesity, are steadily rising. Singapore's CVD economic burden is estimated to be 8.1 billion USD (11.5 billion SGD). The burden of CVD can only be reduced using individual and population-based approaches. Prevention programs must also be developed based on an understanding of risk trends. Therefore, this article attempts to capture the burden of CVD, trends in risk factor control, preventive care, disparities, and current unmet needs, particularly in atherosclerotic cardiovascular disease management in Singapore.

Readmissions, Death and Its Associated Predictors in Heart Failure With Preserved Versus Reduced Ejection Fraction.

Background Data on rehospitalizations for heart failure (HF) in Asia are scarce. We sought to determine the burden and predictors of HF (first and recurrent) rehospitalizations and all-cause mortality in patients with HF and preserved versus reduced ejection fraction (preserved EF, ≥50%; reduced EF, <40%), in the multinational ASIAN-HF (Asian Sudden Cardiac Death in Heart Failure) registry. Methods and Results Patients with symptomatic (stage C) chronic HF were followed up for death and recurrent HF hospitalizations for 1 year. Predictors of HF hospitalizations or all-cause mortality were examined with Cox regression for time to first event and other methods for recurrent events analyses. Among 1666 patients with HF with preserved EF (mean age, 68±12 years; 50% women), and 4479 with HF with reduced EF (mean age, 61±13 years; 22% women), there were 642 and 2302 readmissions, with 28% and 45% attributed to HF, respectively. The 1-year composite event rate for first HF hospitalization or all-cause death was 11% and 21%, and for total HF hospitalization and all-cause death was 17.7 and 38.7 per 100 patient-years in HF with preserved EF and HF with reduced EF, respectively. In HF with preserved EF, consistent independent predictors of these clinical end points included enrollment as an inpatient, Southeast Asian location, and comorbid chronic kidney disease or atrial fibrillation. The same variables were predictive of outcomes in HF with reduced EF except atrial fibrillation, and also included Northeast Asian location, older age, elevated heart rate, decreased systolic blood pressure, diabetes, smoking, and non-usage of beta blockers. Conclusions One-year HF rehospitalization and mortality rates were high among Asian patients with HF. Predictors of outcomes identified in this study could aid in risk stratification and timely interventions. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01633398.

α-Synuclein Strains: Does Amyloid Conformation Explain the Heterogeneity of Synucleinopathies?

Synucleinopathies are a heterogeneous group of neurodegenerative diseases with amyloid deposits that contain the α-synuclein (SNCA/α-Syn) protein as a common hallmark. It is astonishing that aggregates of a single protein are able to give rise to a whole range of different disease manifestations. The prion strain hypothesis offers a possible explanation for this conundrum. According to this hypothesis, a single protein sequence is able to misfold into distinct amyloid structures that can cause different pathologies. In fact, a growing body of evidence suggests that conformationally distinct α-Syn assemblies might be the causative agents behind different synucleinopathies. In this review, we provide an overview of research on the strain hypothesis as it applies to synucleinopathies and discuss the potential implications for diagnostic and therapeutic purposes.

Reducing INS-IGF1 signaling protects against non-cell autonomous vesicle rupture caused by SNCA spreading.

Aging is associated with a gradual decline of cellular proteostasis, giving rise to devastating protein misfolding diseases, such as Alzheimer disease (AD) or Parkinson disease (PD). These diseases often exhibit a complex pathology involving non-cell autonomous proteotoxic effects, which are still poorly understood. Using Caenorhabditis elegans we investigated how local protein misfolding is affecting neighboring cells and tissues showing that misfolded PD-associated SNCA/α-synuclein is accumulating in highly dynamic endo-lysosomal vesicles. Irrespective of whether being expressed in muscle cells or dopaminergic neurons, accumulated proteins were transmitted into the hypodermis with increasing age, indicating that epithelial cells might play a role in remote degradation when the local endo-lysosomal degradation capacity is overloaded. Cell biological and genetic approaches revealed that inter-tissue dissemination of SNCA was regulated by endo- and exocytosis (neuron/muscle to hypodermis) and basement membrane remodeling (muscle to hypodermis). Transferred SNCA conformers were, however, inefficiently cleared and induced endo-lysosomal membrane permeabilization. Remarkably, reducing INS (insulin)-IGF1 (insulin-like growth factor 1) signaling provided protection by maintaining endo-lysosomal integrity. This study suggests that the degradation of lysosomal substrates is coordinated across different tissues in metazoan organisms. Because the chronic dissemination of poorly degradable disease proteins into neighboring tissues exerts a non-cell autonomous toxicity, this implies that restoring endo-lysosomal function not only in cells with pathological inclusions, but also in apparently unaffected cell types might help to halt disease progression.Abbreviations: AD: Alzheimer disease; BM: basement membrane; BWM: body wall muscle; CEP: cephalic sensilla; CLEM: correlative light and electron microscopy; CTNS-1: cystinosin (lysosomal protein) homolog; DA: dopaminergic; DAF-2: abnormal dauer formation; ECM: extracellular matrix; FLIM: fluorescence lifetime imaging microscopy; fps: frames per second; GFP: green fluorescent protein; HPF: high pressure freezing; IGF1: insulin-like growth factor 1; INS: insulin; KD: knockdown; LMP: lysosomal membrane permeabilization; MVB: multivesicular body; NOC: nocodazole; PD: Parkinson disease; RFP: red fluorescent protein; RNAi: RNA interference; sfGFP: superfolder GFP; SNCA: synuclein alpha; TEM: transmission electron microscopy; TNTs: tunneling nanotubes; TCSPC: time correlated single photon counting; YFP: yellow fluorescent protein.

Targeting Plasmodium PI(4)K to eliminate malaria.

Achieving the goal of malaria elimination will depend on targeting Plasmodium pathways essential across all life stages. Here we identify a lipid kinase, phosphatidylinositol-4-OH kinase (PI(4)K), as the target of imidazopyrazines, a new antimalarial compound class that inhibits the intracellular development of multiple Plasmodium species at each stage of infection in the vertebrate host. Imidazopyrazines demonstrate potent preventive, therapeutic, and transmission-blocking activity in rodent malaria models, are active against blood-stage field isolates of the major human pathogens P. falciparum and P. vivax, and inhibit liver-stage hypnozoites in the simian parasite P. cynomolgi. We show that imidazopyrazines exert their effect through inhibitory interaction with the ATP-binding pocket of PI(4)K, altering the intracellular distribution of phosphatidylinositol-4-phosphate. Collectively, our data define PI(4)K as a key Plasmodium vulnerability, opening up new avenues of target-based discovery to identify drugs with an ideal activity profile for the prevention, treatment and elimination of malaria.

Ethylene glycol metabolism by Pseudomonas putida.

In this study, we investigated the metabolism of ethylene glycol in the Pseudomonas putida strains KT2440 and JM37 by employing growth and bioconversion experiments, directed mutagenesis, and proteome analysis. We found that strain JM37 grew rapidly with ethylene glycol as a sole source of carbon and energy, while strain KT2440 did not grow within 2 days of incubation under the same conditions. However, bioconversion experiments revealed metabolism of ethylene glycol by both strains, with the temporal accumulation of glycolic acid and glyoxylic acid for strain KT2440. This accumulation was further increased by targeted mutagenesis. The key enzymes and specific differences between the two strains were identified by comparative proteomics. In P. putida JM37, tartronate semialdehyde synthase (Gcl), malate synthase (GlcB), and isocitrate lyase (AceA) were found to be induced in the presence of ethylene glycol or glyoxylic acid. Under the same conditions, strain KT2440 showed induction of AceA only. Despite this difference, the two strains were found to use similar periplasmic dehydrogenases for the initial oxidation step of ethylene glycol, namely, the two redundant pyrroloquinoline quinone (PQQ)-dependent enzymes PedE and PedH. From these results we constructed a new pathway for the metabolism of ethylene glycol in P. putida. Furthermore, we conclude that Pseudomonas putida might serve as a useful platform from which to establish a whole-cell biocatalyst for the production of glyoxylic acid from ethylene glycol.

Total synthesis confirms laetirobin as a formal Diels-Alder adduct.

Laetirobin, isolated from a parasitic fungus host-plant relationship, was synthesized in six practical steps with an overall yield of 12% from commercially available 2,4-dihydroxyacetophenone. Because the product is a pseudosymmetric tetramer of benzo[b]furans, each step of the synthesis was designed to involve tandem operations. Highlights include: 1) the double Sonogashira reaction of a bis(alkyne), 2) the practical copper(I)-mediated formation of a bis(benzo[b]furan), and 3) the biomimetic [4+2] dimerization and unexpected cationic [5+2] annulation of gem-diaryl alkene precursors. Preliminary structure-activity relationship data between the isomeric [4+2] and [5+2] tetramers revealed only the natural product to possess promising anticancer potential. Specifically, laetirobin is capable of blocking tumor cell division (mitosis) and invoking programmed cell death (apoptosis).

Laetirobin from the parasitic growth of Laetiporus sulphureus on Robinia pseudoacacia.

(+/-)-Laetirobin (1) was isolated as a cytostatic lead from Laetiporus sulphureus growing parasitically on the black locust tree, Robinia pseudoacacia, by virtue of a reverse-immunoaffinity system. Using an LC/MS procedure, milligram quantities of (+/-)-laetirobin (1) were obtained, and the structure of 1 was elucidated by X-ray crystallography and confirmed by NMR spectroscopy. Preliminary cellular studies indicated that (+/-)-laetirobin (1) rapidly enters in tumor cells, blocks cell division at a late stage of mitosis, and invokes apoptosis.

Characterization of platelet proteins using peptide centric proteomics.

In modern proteomics, undersampling of low abundant, cumbersome, and hydrophobic proteins states one of the major problems. To overcome this, especially in two 2D-PAGE (two-dimensional polyacrylamide gel electrophoresis) eminent drawbacks, the so-called peptide-centric techniques have been developed. These approaches do not separate proteins prior to digestion, but instead proteolytically generate peptide mixtures after it. However, by this procedure already complex protein mixtures become even more extensive peptide mixtures. Particularly, when dealing with large proteomes, the generated sample complexity is vast and therefore difficult to analyze. When separated and analyzed by LC/MS, too many peptides may enter the mass spectrometer at a certain time point, and only a small fraction of ions is selected for subsequent MS/MS analysis. Although protein hydrophobicity and size play minor roles (as long as protease cleavage sites are accessible), low copy number can severely limit identification rates. To reduce the amount of peptides entering the mass spectrometer simultaneously without the loss of overall proteomic information, different techniques have been developed. Among these, an approach is represented by COFRADIC (Combined Fractional Diagonal Chromatography). COFRADIC is a chromatography-based technique enabling the sorting of peptides due to retention time shifts after a specific modification step. In the original approach, a complex peptide mixture is separated by a primary RP-HPLC (reversed-phase high-performance liquid chromatography) run and fractions are retained. Subsequently, these fractions are modified to specifically change retention times of peptides and separated in one or more secondary RP-HPLC runs. In this chapter, COFRADIC approaches for methionine or cysteine containing as well as N-terminal peptides are described. Besides the reduction of sample complexity, the major advantage of COFRADIC might be seen in its versatility. Nearly every feature unique for a subset of peptides, which can be specifically modified by a sorting reaction, is accessible for COFRADIC. Among these are protein phosphorylation, N-glycosylation, and in vivo protein processing sites. Finally, COFRADIC allows the analysis of large numbers of samples and is highly automatable.

Inhibition of restenosis in stented porcine coronary arteries: uptake of Paclitaxel from angiographic contrast media.

RATIONALE AND OBJECTIVES: Paclitaxel added to angiographic contrast medium (CM) has been shown to inhibit restenosis in the porcine coronary overstretch model. This study determined early local tissue concentrations after the administration of different paclitaxel doses and preparations. MATERIALS AND METHODS: Fifteen pigs received 2 stents each in the left coronary artery. During and/or after the intervention, paclitaxel-containing CM or diluted Taxol was injected. Fifteen minutes after the last intracoronary injection, paclitaxel concentrations in the arterial wall and myocardium were measured by high-performance liquid chromatography. RESULTS: Mean paclitaxel concentrations in the left coronary arteries reached 3-10 microM. Higher volumes and higher paclitaxel concentrations resulted in higher tissue concentrations. Paclitaxel in CM was better tolerated and led to higher local concentrations than diluted Taxol. Low paclitaxel concentrations in the uninjected right coronary artery and in plasma indicate selectivity. CONCLUSION: When admixed to CM, paclitaxel results in local tissue concentrations proportional to the amount of the drug injected.