Lifelong endurance exercise and its relation with coronary atherosclerosis

AIMS

The impact of long-term endurance sport participation (on top of a healthy lifestyle) on coronary atherosclerosis and acute cardiac events remains controversial.

METHODS AND RESULTS

The Master@Heart study is a well-balanced prospective observational cohort study. Overall, 191 lifelong master endurance athletes, 191 late-onset athletes (endurance sports initiation after 30 years of age), and 176 healthy non-athletes, all male with a low cardiovascular risk profile, were included. Peak oxygen uptake quantified fitness. The primary endpoint was the prevalence of coronary plaques (calcified, mixed, and non-calcified) on computed tomography coronary angiography. Analyses were corrected for multiple cardiovascular risk factors. The median age was 55 (50-60) years in all groups. Lifelong and late-onset athletes had higher peak oxygen uptake than non-athletes [159 (143-177) vs. 155 (138-169) vs. 122 (108-138) % predicted]. Lifelong endurance sports was associated with having ≥1 coronary plaque [odds ratio (OR) 1.86, 95% confidence interval (CI) 1.17-2.94], ≥ 1 proximal plaque (OR 1.96, 95% CI 1.24-3.11), ≥ 1 calcified plaques (OR 1.58, 95% CI 1.01-2.49), ≥ 1 calcified proximal plaque (OR 2.07, 95% CI 1.28-3.35), ≥ 1 non-calcified plaque (OR 1.95, 95% CI 1.12-3.40), ≥ 1 non-calcified proximal plaque (OR 2.80, 95% CI 1.39-5.65), and ≥1 mixed plaque (OR 1.78, 95% CI 1.06-2.99) as compared to a healthy non-athletic lifestyle.

CONCLUSION

Lifelong endurance sport participation is not associated with a more favourable coronary plaque composition compared to a healthy lifestyle. Lifelong endurance athletes had more coronary plaques, including more non-calcified plaques in proximal segments, than fit and healthy individuals with a similarly low cardiovascular risk profile. Longitudinal research is needed to reconcile these findings with the risk of cardiovascular events at the higher end of the endurance exercise spectrum.

Association of left ventricular diastolic function with systolic dyssynchrony: a population study

AIMS

Left ventricular (LV) (dys)synchrony has an important impact on LV function and structure. Our study aimed to describe the distribution and determinants of LV mechanical delay indexes in the general population and to assess an association of different Doppler indexes reflecting LV diastolic function with LV mechanical delay indexes.

METHODS AND RESULTS

In 200 subjects enrolled in a family-based population study (46.5% women; mean age, 57.9; 48% hypertensive), we performed echocardiography with tissue synchronization imaging (TSI) and two-dimensional speckle tracking. We measured the maximum difference in time to peak systolic velocity between any 2 of 12 LV segments (Ts-max); the standard deviation of time to peak systolic velocity of 12 segments (Ts-sd); the difference in time to peak systolic velocity and strain between septal and lateral LV walls and the strain delay index in septal and lateral walls [septal and lateral (SDI)]. In univariable and multivariable regression analyses, TSI indexes and lateral SDI independently increased with age (P ≤ 0.027) and body mass index (P ≤ 0.010). Ts-max and Ts-sd also increased with female sex (P ≤ 0.0002) and decreased with heart rate (P ≤ 0.0004). Septal SDI only increased with female sex (P < 0.0001). Among the Doppler indexes of LV diastolic function, only E/e' was significantly and positively associated with TSI indexes (P ≤ 0.037) and lateral SDI (P = 0.0026), but not with septal SDI (P = 0.69). In participants with advanced stage of LV diastolic dysfunction, TSI indexes were prolonged compare with subjects with normal LV diastolic function (P ≤ 0.002).

CONCLUSION

We demonstrated that in unselected subjects LV diastolic dysfunction was associated with mechanical LV dyssynchrony as assessed by echocardiography.

Idebenone as a novel, therapeutic approach for Duchenne muscular dystrophy: results from a 12 month, double-blind, randomized placebo-controlled trial

Early mortality in Duchenne muscular dystrophy (DMD) is related to cardiac and respiratory complications. A phase IIa double-blind randomized placebo-controlled clinical trial was conducted to investigate the tolerability and efficacy of idebenone therapy in children with DMD. Twenty-one DMD patients (aged 8-16 years) were randomly assigned to daily treatment with 450 mg idebenone (Catena®) (n=13) or placebo (n=8) for 12 months. All subjects completed the study and idebenone was safe and well tolerated. Idebenone treatment resulted in a trend (p=0.067) to increase peak systolic radial strain in the left ventricular inferolateral wall, the region of the heart that is earliest and most severely affected in DMD. A significant respiratory treatment effect on peak expiratory flow was observed (p=0.039 for PEF and p=0.042 for PEF percent predicted). Limitations of this study were the small sample size, and a skewed age distribution between treatment groups. Data from this study provided the basis for the planning of a confirmatory study.

Quantitative dobutamine stress echocardiography for the early detection of cardiac allograft vasculopathy in heart transplant recipients

BACKGROUND

A non-invasive method to detect the presence of cardiac allograft vasculopathy (CAV) remains an important goal in clinical cardiology.

OBJECTIVE

To assess the value of quantitative dobutamine stress echocardiography (DSE) for the early detection of CAV.

METHODS

42 heart transplant recipients underwent DSE with acquisition of both conventional two-dimensional and colour tissue Doppler data. All studies were analysed conventionally and quantitatively using regional deformation parameters-that is, peak systolic longitudinal strain (in(peak sys)), strain rate (SR(peak sys)) and post-systolic strain index. Myocardial segments were classified as normal, mildly abnormal or severely abnormal based on correlative angiographic findings.

RESULTS

At baseline, in(peak sys) was significantly lower in severely abnormal segments than in normal ones. However, at peak stress, in(peak sys) was able to separate three groups of segments. Receiver operating characteristic analysis showed an SR(peak sys) response of <0.5/s to identify patients with CAV with a sensitivity of 88%, specificity of 85% and a negative predictive value of 92%.

CONCLUSION

Regional myocardial function is impaired in heart transplant recipients with CAV even when the disease is considered to be non-significant on conventional angiography. Systolic deformation parameters tended to detect the existence of CAV more accurately than conventional visual DSE assessment. Strain rate imaging during stress can therefore safely be used as a non-invasive screening test for detecting CAV in heart transplant recipients.

Conservation of hotspots for recombination in low-copy repeats associated with the NF1 microdeletion

Several large-scale studies of human genetic variation have provided insights into processes such as recombination that have shaped human diversity. However, regions such as low-copy repeats (LCRs) have proven difficult to characterize, hindering efforts to understand the processes operating in these regions. We present a detailed study of genetic variation and underlying recombination processes in two copies of an LCR (NF1REPa and NF1REPc) on chromosome 17 involved in the generation of NF1 microdeletions and in a third copy (REP19) on chromosome 19 from which the others originated over 6.7 million years ago. We find evidence for shared hotspots of recombination among the LCRs. REP19 seems to contain hotspots in the same place as the nonallelic recombination hotspots in NF1REPa and NF1REPc. This apparent conservation of patterns of recombination hotspots in moderately diverged paralogous regions contrasts with recent evidence that these patterns are not conserved in less-diverged orthologous regions of chimpanzees.

Comparison of real-time tri-plane and conventional 2D dobutamine stress echocardiography for the assessment of coronary artery disease

AIMS

Although dobutamine stress echocardiography (DSE) is an accepted tool for the diagnosis of coronary artery disease (CAD), it requires subsequent image acquisitions of the left ventricle (LV) in order to visualize all segments. This makes the procedure relatively time-consuming and might limit its accuracy. With the introduction of matrix array transducers, the real-time simultaneous acquisition of all LV segments has become possible using multi-plane imaging. The purpose of this study was: (i) to test the feasibility and efficiency of real-time tri-plane (RT3P) imaging during DSE, (ii) to compare the accuracy of RT3P DSE in detecting CAD using coronary angiography as the reference method.

METHODS AND RESULTS

Thirty-six patients suspected of CAD were prospectively enrolled. Both conventional two-dimensional (2D) and RT3P imaging were performed during a DSE protocol. Coronary angiography was performed within 24 h. Ultrasound data were acquired at each stage of the DSE. The total effective acquisition time for RT3P imaging was significantly shorter (55+/-29 vs. 137+/-63 s, P<0.001). Data yield was similar for both methods (2D: 98% vs. 3D: 97%). Overall sensitivity (93%), specificity (75%), and accuracy (89%) were identical between both methods. On a segmental level, the sensitivity, specificity, and accuracy of the RT3P and the 2D DSE were similar.

CONCLUSION

RT3P imaging fastens the DSE protocol without compromising the accuracy for the diagnosis of CAD. This could facilitate a more wide-spread use of DSE and therefore contributes positively to its routine clinical acceptance.

Interaction of miconazole, ketoconazole and itraconazole with rat-liver microsomes

The interaction of the antimycotics miconazole, ketoconazole and itraconazole with liver microsomes from untreated rats or from rats pretreated with phenobarbital or 3-methylcholanthrene, gave rise to type II difference spectra. The interactions of the antimycotics with control, phenobarbital-induced or 3-methylcholanthrene-induced microsomes were biphasic, except for the monophasic binding of ketoconazole to phenobarbital-induced microsomes. The N-demethylation of N,N-dimethylaniline, the O-demethylation of p-nitroanisole and the hydroxylation of aniline in microsomes from untreated and inducer-treated rats were lowered by miconazole and ketoconazole, the former being the more potent inhibitor. Control microsomes were less sensitive than induced microsomes. Itraconazole was almost devoid of inhibitory properties. The three antimycotics were non-competitive (mixed) inhibitors of enzyme activities in phenobarbital-induced microsomes. The Ki values were of the same order of magnitude as the Ks values, except for itraconazole. For the latter drug, Ki values were much greater than could be expected from the spectral studies. It is concluded that the antimycotics affect microsomal enzyme activities via a direct interaction of an azole-nitrogen with the haem group of cytochrome P-450. The interaction with mammalian cytochrome P-450 decreases from miconazole greater than ketoconazole much greater than itraconazole and is much weaker than the interaction of the antimycotics with yeast cytochrome P-450.

Induction potential of antifungals containing an imidazole or triazole moiety. Miconazole and ketoconazole, but not itraconazole are able to induce hepatic drug metabolizing enzymes of male rats at high doses

Male Wistar rats were dosed with miconazole, ketoconazole and itraconazole by gastric intubation once daily for up to 7 days. A dose- and time-dependent induction of the hepatic drug metabolizing enzyme system was observed for miconazole and ketoconazole, while itraconazole proved to be devoid of inductive properties even at the highest dose studied (160 mg/kg). No effect on drug metabolizing enzymes could be demonstrated for either drug at a dose level of 10 mg/kg, which is just above the antifungally active dose. At a dose of 40 mg/kg, miconazole, but not ketoconazole, significantly increased cytochrome P-450 content. At the highest dose of 160 mg/kg, both miconazole and ketoconazole increased the relative liver weight, the cytochrome P-450- and b5-content and NADPH-cyt c-reductase. Furthermore, miconazole, but not ketoconazole, increased specific microsomal aminopyrine and N,N-dimethylaniline N-demethylase activity, p-nitroanisole O-demethylase activity and UDP-glucuronyltransferase activity towards 4-nitrophenol while the specific aniline hydroxylase activity was unaffected. Ketoconazole at 160 mg/kg only induced O-demethylase activity and UDP-glucuronyltransferase activity, while it lowered the specific activities towards the other substrates. Miconazole was a relatively more potent inducer when compared to ketoconazole. Both drugs displayed biphasic effects on the mixed-function oxidase activities, which were lowered after acute administration (160 mg/kg, 1 hr before death) and were induced when determined after 23 hr had elapsed or after multiple dosage. Both drugs bound strongly to their respective induced cytochromes, giving rise to type II difference spectra, and inhibited the O-demethylase activity of the induced microsomes with an I50 of 5.2 microM for miconazole and 15.1 microM for ketoconazole. On the basis of a comparison of the enzymatic activities induced by both antimycotics with those induced by PB or 3-MC, it was concluded that miconazole behaved as a PB-type inducer, whereas ketoconazole did not belong to either category of inducers. A comparison of electrophoretograms of microsomes from different origins on SDS-PAGE revealed that miconazole increased the concentration of several proteins, whereas ketoconazole selectively induced a protein with Mr of 47,800. The protein pattern in the 50 kDa region of miconazole-induced microsomes resembled that of PB-microsomes qualitatively.