Limited information is available on office and ambulatory blood pressure (BP) control as well as on cardiovascular (CV) risk profile in treated hypertensive patients living in central and eastern ...European countries.
In 2008, a survey on 7860 treated hypertensive patients followed by non-specialist or specialist physicians was carried out in nine central and eastern European countries (Albania, Belarus, Bosnia, Czech Republic, Latvia, Romania, Serbia, Slovakia, and Ukraine). Cardiovascular risk assessment was based on personal history, clinic BP values, as well as target organ damage evaluation. Patients had a mean (±SD) age of 60.1 ± 11 years, and the majority of them (83.5%) were followed by specialists. Average clinic BP was 149.3 ± 17/88.8 ± 11 mmHg. About 70% of patients displayed a very high-risk profile. Electrocardiogram was performed in 99% of patients, echocardiography in 65%, carotid ultrasound in 24%, fundoscopy in 68%, and search for microalbuminuria in 10%. Ambulatory BP monitoring was performed in about one-fifth of the recruited patients. Despite the widespread use of combination treatment (87% of the patients), office BP control (<140/90 mmHg) was achieved in 27.1% only, the corresponding control rate for ambulatory BP (<130/80 mmHg) being 35.7%. Blood pressure control was (i) variable among different countries, (ii) worse for systolic than for diastolic BP, (iii) slightly better in patients followed by specialists than by non-specialists, (iv) unrelated to patients' age, and (v) more unsatisfactory in high-risk hypertensives and in patients with coronary heart disease, stroke, or renal failure.
These data provide evidence that in central and eastern European countries office and ambulatory BP control are unsatisfactory, particularly in patients at very high CV risk, and not differ from that seen in Western Europe. They also show that assessment of subclinical organ damage is quite common, except for microalbuminuria, and that combination drug treatment is frequently used.
Ambulatory blood pressure (ABP) has only rarely been employed in population studies because of the difficulty posed by the greater complexity of this technique. The cross-sectional studies that have ...been published, however, have allowed a number of conclusions to be drawn. One, 24h average blood pressure of populations is significantly but not closely related to office blood pressure, which thus can not predict accurately daily-life values of blood pressure. Two, 24h average blood pressure is usually less than office blood pressure, the discrepancy increasing with the increase in office values and being of magnitude several mmHg at the office blood pressure of 140/90 mmHg (systolic/diastolic) Three, ABP in women is somewhat less than that in men and ABP for both sexes increases less with aging than does office blood pressure. Four, a circadian profile of blood pressure consisting in values that are much lower at night than are those during daytime characterizes both sexes and all ages with the possible exception of individuals aged 75 years and more, in whom the nocturnal hypotension appears to be attenuated. A similar attenuation has been found for blacks in comparison with whites. The upper limit of normality of ABP has not yet been defined conclusively, although 24h average values </=125/80 mmHg are almost invariably regarded as normal. Normality of ABP should be defined, however, by longitudinal population studies in which ambulatory values are related to prognosis. One of these studies has already been published and others will be completed in the near future.
Phosphorylated H2AX (γ-H2AX) is a sensitive marker for DNA double-strand breaks (DSBs), but the variability of H2AX expression in different cell and tissue types makes it difficult to interpret the ...meaning of the γ-H2AX level. Furthermore, the assays commonly used for γ-H2AX detection utilize laborious and low-throughput microscopy-based methods. We describe here an ELISA assay that measures both phosphorylated H2AX and total H2AX absolute amounts to determine the percentage of γ-H2AX, providing a normalized value representative of the amount of DNA damage. We demonstrate the utility of the assay to measure DSBs introduced by either ionizing radiation or DNA-damaging agents in cultured cells and in xenograft models. Furthermore, utilizing the NCI-60 cancer cell line panel, we show a correlation between the basal fraction of γ-H2AX and cellular mutation levels. This additional application highlights the ability of the assay to measure γ-H2AX levels in many extracts at once, making it possible to correlate findings with other cellular characteristics. Overall, the γ-H2AX ELISA represents a novel approach to quantifying DNA damage, which may lead to a better understanding of mutagenic pathways in cancer and provide a useful biomarker for monitoring the effectiveness of DNA-damaging anticancer agents.
Several front-line chemotherapeutics cause mitochondria-derived, oxidative stress-mediated cardiotoxicity. Iron chelators and other antioxidants have not completely succeeded in mitigating this ...effect. One hindrance to the development of cardioprotectants is the lack of physiologically-relevant animal models to simultaneously study antitumor activity and cardioprotection. Therefore, we optimized a syngeneic rat model and examined the mechanisms by which oxidative stress affects outcome. Immune-competent spontaneously hypertensive rats (SHRs) were implanted with passaged, SHR-derived, breast tumor cell line, SST-2. Tumor growth and cytokine responses (IL-1A, MCP-1, TNF-α) were observed for two weeks post-implantation. To demonstrate the utility of the SHR/SST-2 model for monitoring both anticancer efficacy and cardiotoxicity, we tested cardiotoxic doxorubicin alone and in combination with an established cardioprotectant, dexrazoxane, or a nitroxide conjugated to a triphenylphosphonium cation, Mito-Tempol (4) Mito-T (4). As predicted, tumor reduction and cardiomyopathy were demonstrated by doxorubicin. We confirmed mitochondrial accumulation of Mito-T (4) in tumor and cardiac tissue. Dexrazoxane and Mito-T (4) ameliorated doxorubicin-induced cardiomyopathy without altering the antitumor activity. Both agents increased the pro-survival autophagy marker LC3-II and decreased the apoptosis marker caspase-3 in the heart, independently and in combination with doxorubicin. Histopathology and transmission electron microscopy demonstrated apoptosis, autophagy, and necrosis corresponding to cytotoxicity in the tumor and cardioprotection in the heart. Changes in serum levels of 8-oxo-dG-modified DNA and total protein carbonylation corresponded to cardioprotective activity. Finally, 2D-electrophoresis/mass spectrometry identified specific serum proteins oxidized under cardiotoxic conditions. Our results demonstrate the utility of the SHR/SST-2 model and the potential of mitochondrially-directed agents to mitigate oxidative stress-induced cardiotoxicity. Our findings also emphasize the novel role of specific protein oxidation markers and autophagic mechanisms for cardioprotection.
Abstract
Aims
The Brugada syndrome (BrS) is an inherited cardiac disorder predisposing to ventricular arrhythmias. Despite considerable efforts, its genetic basis and cellular mechanisms remain ...largely unknown. The objective of this study was to identify a new susceptibility gene for BrS through familial investigation.
Methods and results
Whole-exome sequencing performed in a three-generation pedigree with five affected members allowed the identification of one rare non-synonymous substitution (p.R211H) in RRAD, the gene encoding the RAD GTPase, carried by all affected members of the family. Three additional rare missense variants were found in 3/186 unrelated index cases. We detected higher levels of RRAD transcripts in subepicardium than in subendocardium in human heart, and in the right ventricle outflow tract compared to the other cardiac compartments in mice. The p.R211H variant was then subjected to electrophysiological and structural investigations in human cardiomyocytes derived from induced pluripotent stem cells (iPSC-CMs). Cardiomyocytes derived from induced pluripotent stem cells from two affected family members exhibited reduced action potential upstroke velocity, prolonged action potentials and increased incidence of early afterdepolarizations, with decreased Na+ peak current amplitude and increased Na+ persistent current amplitude, as well as abnormal distribution of actin and less focal adhesions, compared with intra-familial control iPSC-CMs Insertion of p.R211H-RRAD variant in control iPSCs by genome editing confirmed these results. In addition, iPSC-CMs from affected patients exhibited a decreased L-type Ca2+ current amplitude.
Conclusion
This study identified a potential new BrS-susceptibility gene, RRAD. Cardiomyocytes derived from induced pluripotent stem cells expressing RRAD variant recapitulated single-cell electrophysiological features of BrS, including altered Na+ current, as well as cytoskeleton disturbances.
Numerous types of DNA variation exist, ranging from SNPs to larger structural alterations such as copy number variants (CNVs) and inversions. Alignment of DNA sequence from different sources has been ...used to identify SNPs and intermediate-sized variants (ISVs). However, only a small proportion of total heterogeneity is characterized, and little is known of the characteristics of most smaller-sized (<50 kb) variants. Here we show that genome assembly comparison is a robust approach for identification of all classes of genetic variation. Through comparison of two human assemblies (Celera's R27c compilation and the Build 35 reference sequence), we identified megabases of sequence (in the form of 13,534 putative non-SNP events) that were absent, inverted or polymorphic in one assembly. Database comparison and laboratory experimentation further demonstrated overlap or validation for 240 variable regions and confirmed >1.5 million SNPs. Some differences were simple insertions and deletions, but in regions containing CNVs, segmental duplication and repetitive DNA, they were more complex. Our results uncover substantial undescribed variation in humans, highlighting the need for comprehensive annotation strategies to fully interpret genome scanning and personalized sequencing projects.
Purpose
Indenoisoquinolines are non-camptothecin topoisomerase I (TopI) inhibitors that overcome the limitations of camptothecins: chemical instability and camptothecin resistance. Two dosing ...schedules of the novel indenoisoquinoline, indotecan (LMP400), were evaluated in patients with advanced solid tumors.
Methods
The maximum tolerated dose (MTD), toxicities, and pharmacokinetics of two indotecan drug administration schedules (daily for 5 days or weekly) were investigated. Modulation of TopI and the phosphorylation of histone H2AX (γH2AX) were assayed in tumor biopsies; γH2AX levels were also evaluated in circulating tumor cells (CTCs) and hair follicles to assess DNA damage response.
Results
An MTD of 60 mg/m
2
/day was established for the daily regimen, compared to 90 mg/m
2
for the weekly regimen. The TopI response to drug showed target engagement in a subset of tumor biopsies. Pharmacokinetics profiles demonstrated a prolonged terminal half-life and tissue accumulation compared to topotecan. Dose-dependent decreases in total CTCs were measured in seven patients. Formation of γH2AX-positive foci in CTCs (day 3) and hair follicles (4–6 h) was observed following treatment.
Conclusions
We established the MTD of two dosing schedules for a novel TopI inhibitor, indotecan. Target engagement was demonstrated as Top1 downregulation and γH2AX response. No objective responses were observed on either schedule in this small patient cohort. The principal toxicity of both schedules was myelosuppression; no significant gastrointestinal problems were observed. Increased DNA damage response was observed in CTCs, hair follicles, and a subset of tumor biopsies.
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