Thin-cap fibroatheroma and increased coronary intima-media thickness are associated with an altered balance of arginine metabolites

INTRODUCTION

Arginase inhibition increases plasma citrulline and citrulline / ornithine (C/O) ratio, and reduces plasma ornithine and ornithine / arginine (O/A) ratio in an animal model of myocardial infarction (MI).

OBJECTIVES

We hypothesized that the presence of thin‑cap fibroatheroma (TCFA) in the culprit lesion and increased non‑culprit intima‑media thickness of an infarct‑related artery (IRA) are associated with an altered balance of arginine metabolites.

PATIENTS AND METHODS

Arginine and its metabolites were measured using liquid chromatography and tandem mass spectrometry in 100 consecutive MI patients upon admission and at 6‑month follow‑up. TCFA and adjacent to culprit lesion proximal and distal 10‑mm segments were assessed with optical coherence tomography in the acute phase. Twenty five patients without coronary lesions on angiography served as controls.

RESULTS

The C/O ratio increased 5.33 times (P <0.001), while the O/A ratio decreased 2.53 times (P <0.001) at the 6‑month follow‑up, as compared with the acute phase of MI. The patients with (n = 75) vs without (n = 25) TCFA had lower C/O ratio by 29% (P = 0.003), while the mean intima‑media diameter of adjacent non‑culprit region correlated with the follow‑up O/A ratio (R = 0.337; P = 0.003). In a multivariable analysis, a higher acute phase C/O ratio was associated with a lower risk of TCFA presence (odds ratio, 0.978; 95% CI, 0.962-0.994; P = 0.006), whereas a higher follow‑up O/A ratio correlated with larger intima‑media diameter of the adjacent segments (β coefficient, 0.227; 95% CI for β coefficient, 0.045-0.409; P = 0.018).

CONCLUSIONS

Enhanced arginase activity over nitric oxide synthase following ischemia was associated with the presence of TCFA in the culprit lesion, while a similar metabolic shift in the chronic phase correlated with a greater thickness of the intima‑media in the adjacent non‑culprit IRA segments.

An altered balance of plasma arginine metabolites is associated with increased thickness of the coronary intima-media complex in the adjacent to the culprit segment of an infarct-related artery

Background

The biomarkers of atherosclerosis remain insufficiently understood.

Purpose

We sought to investigate whether an altered balance of arginine metabolites in patients following myocardial infarction (MI) is associated with remodeling of the adjacent to the culprit segments of an infarct-related artery (IRA) and with clinical outcomes.

Methods

Arginine and its metabolites including ornithine, citrulline, proline and asymmetric dimethylarginine were measured using liquid chromatography and tandem mass spectrometry in 85 consecutive ST-segment elevation MI patients upon admission and at 6-month follow-up and were compared with morphology of the adjacent to the culprit proximal and distal 10-mm segments of IRA assessed with optical coherence tomography. A composite ischemic event was defined as death, recurrent MI, stroke, or unplanned percutaneous coronary intervention.

Results

The ratios of citrulline/ornithine and citrulline/arginine decreased 5.22 and 2.20 times (both P&lt;0.001) respectively, while the ornithine/arginine index (I_O/A) increased 2.96 times (P&lt;0.001) following ischemia compared with stable follow-up, indicating the enhanced arginase activity over nitric oxide synthase (NOS) in acute phase of STEMI. Follow-up I_O/A correlated with the mean intima-media (R=0.34, P=0.003, Figure 1A) and intima (R=0.30, P=0.008) diameter of an adjacent to the culprit IRA segment. By multivariate analysis, apart from male gender (P&lt;0.001) and diabetes mellitus (P=0.02), a higher follow-up I_O/A was associated with the larger mean intima-media diameter of an adjacent to the culprit IRA segments (coefficient 0.218, 95% confidence interval 0.040–0.397, P=0.017, per 0.01). Within the median follow-up of 25 (19–35) months, ischemic composite endpoint was found in 13 (15.3%) patients. The follow-up I_O/A reached the area under the ROC curve of 0.78 (95% confidence interval 0.66–0.91, P=0.005) for prediction of composite ischemic endpoint with a cut-off value of ≥0.57, and a sensitivity of 72.3% and specificity of 80.0% (Figure !B).

Conclusions

Our findings provide arguments that during the acute phase of MI, arginine metabolism is shifted from NOS towards arginase, as compared to 6-month stable conditions. Simultaneously, the enhanced residual arginase activity over NOS in chronic phase was correlated with a higher thickness of intima or intima-media in the adjacent to the culprit segment within the IRA, and was also associated with unfavorable clinical outcomes.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Grant of the National Science Center of Poland (Number 2016/21/B/NZ5/01378 to J.Z.)

Short communication: Locus-specific interrelations between gene expression and DNA methylation patterns in bovine mammary gland infected by coagulase-positive and coagulase-negative staphylococci

Pathogens are able to alter the cell cycle program and immune response of the host by changing the transcription and epigenetics of genes responsible for cell cycle control and inflammation. In this regard, we evaluated interrelations between DNA methylation and expression of autophagy, apoptosis, and lipid metabolism-related genes in a sample set of mammary gland secretory tissue sections derived from bovine mammary glands infected with coagulase-negative and coagulase-positive staphylococci. We assessed relative transcript abundance and DNA bisulfite sequencing in loci of the ATG5, IGF1R, TERT, and DGAT1 genes. Lack of DNA methylation in ATG5 and DGAT1 loci might be associated with maintenance of ATG5 and DGAT1 expression regardless of the health status of bovine mammary gland. Complete methylation of intragenic CpG regions in the IGF1R locus was apparently not related to the presence of its transcript in the investigated udder parenchyma samples. Detected hypermethylation of the TERT upstream element was associated with a small amount of TERT mRNA in bovine mammary gland, regardless of the presence, or absence, of the pathogen. A significant decrease in TERT gene expression in tissue sections of mammary gland free of bacteria and in those infected with coagulase-positive staphylococci was observed in parenchyma samples infected with coagulase-negative staphylococci. Two possible explanations are the direct involvement of the TERT gene in the etiology of bovine mastitis or the increase of TERT mRNA due to activation of the MAPK signaling pathway in response to release of exotoxins by coagulase-negative bacteria in the bovine mammary gland.

Influence of the recurrent syncope episodes on neurocognitive functions in patients with vasovagal syncope

The aim of study was to evaluate an influence of recurrent syncope episodes on the neurocognitive functions (NCF) in patients with suspected VVS.

AIM

The aim of study was to evaluate an influence of recurrent syncope episodes on the neurocognitive functions (NCF) in patients with suspected VVS.

MATERIALS AND METHODS

Study population: 24 pts. (16 women) aged 17-70 yrs (mean age 40 years), with suspected VVS, referred to HUTT (head-up tilt test). All pts. underwent initial evaluation regarding to the number and circumstances of the syncopal and/or presyncopal spells. All pts performed HUTT with Westminster protocol. Basing on the syncope history and HUTT results, two groups of pts were distinguished: gr. I - 18 pts with at least 2 syncopal spells and positive HUTT, and gr. II 6 pts with only presyncopal status without complete loss of consciousness and negative HUTT. All pts underwent the evaluation of NCF with computer-assisted Vienna Test System battery, consisted of the following tests: DAUF - evaluation of long-term selective attention and concentration; COG - assessment of attention and concentration; STROOP - registration of the color-word interference tendency, CORSI - estimation of visual short-term memory capacity and implicite visuo-spatial learning. Values of the measured parameters were compared between both groups of pts.

RESULTS

Patients without syncope (gr. II) had higher number of correctly reproduced sequences (11,0 vs 8,38 p<0,01) and Reliable Spatial Span score (5,50 vs 4,46,p<0,02) in CORSI test, in relation to pts with syncope history (gr. I). This suggests possible influence of the recurrent syncope episodes on the short-term memory capacity in pts with VVS. There were no significant differences between groups, comparing results of the other tests.

CONCLUSIONS

Repeated syncope episodes may lead to impairment of short-term memory capacity in patients with vasovagal syndrome. Syncope episodes may have potentially negative influence on neurocognitive functions in patients with vasovagal syndrome.

Determination of the correlation between stallion's age and number of sex chromosome aberrations in spermatozoa

The aim of this study was a cytogenetic analysis of stallions semen to find sex chromosome aberrations and to determine if there was an association between stallion's age and aberration frequency for the sex chromosomes. Sperm samples were collected from 22 stallions of various age from 3 to 23 years. Multicolour FISH was performed on each sample, using probes for the sex chromosomes and EGFR gene, localized on 4p12 in domestic horse. A total of 26199 sperm cells were analysed (from 1 070 to 1 532 per animal). Among the analysed cells, there were 50.318% with X chromosome, 48.543% with Y chromosome and 1.139% with aberrant chromosomes. The frequency of aberrations was: sex chromosomes nullisomy (0.466%), XY aneuploidy (0.454%), XX disomy (0.146%), YY disomy (0.041%), diploidy (0.024%) and trisomy XXY (0.008%). Additionally there was a correlation between the age of an animal and the frequency of sex chromosome aberration and a significant positive correlation between age and disomy of XY, XX, YY, trisomy of XXY, autosomal disomy was seen. A Correlation between the age of a stallion and the level of nullisomy was negative. The present study demonstrated that FISH technique is a powerful method to identify sex chromosome aberrations in equine spermatozoa and might be very helpful for a breeder during a selection for the best stallion.

The effects of gender and test protocol on the results of head-up tilt test in patients with vasovagal syncope

BACKGROUND

Head-up tilt testing (HUTT) is a well-established method for the diagnosis of reflex syncope. Some controversies exist whether gender and HUTT protocol influence HUTT results.

AIM

To analyse the results of HUTT in patients with syncope in relation to their gender and used protocol of HUTT.

METHODS

We retrospectively analysed data of 537 consecutive patients (313 women and 224 men), aged 13-79 years with history of neurally-mediated syncope referred to HUTT. The cardiogenic and neurological aetiology of syncope was excluded in all patients based on previous examination. In 375 patients standard HUTT (STD HUTT), according to the Westminster protocol, was used. In 257 patients in whom STD HUTT was negative, HUTT was continued with pharmacological provocation using isoproterenol intravenous infusion--114 patients (ISO HUTT) or sublingual nitroglycerin--143 patients (NTG HUTT). In the remaining 162 patients HUTT was performed according to the Italian protocol (ITL HUTT). The HUTT results were classified according to the VASIS scale.

RESULTS

Female gender dominated, however, syncope was induced in a similar proportion of women and men (77.3 vs. 70.5%, NS). There were also no significant differences in the type of vasovagal response (VVR) to HUTT between women and men. Mixed type of VVR was the most frequent after isoproterenol provocation (ISO HUTT), whereas cardioinhibitory type of VVR was the most frequent after nitroglycerin provocation (NTG HUTT).

CONCLUSIONS

There is no significant relationship between gender and the result of HUTT. The type of VVR is related to HUTT protocol--cardioinhibitory response is more frequent following nitroglycerin administration in comparison to standard protocol and HUTT with isoproterenol provocation.

Evaluation of sinus and atrioventricular nodes function in patients with vasovagal syncope

AIM

Evaluation of sinus and atrioventricular nodes function as a potential factor responsible for prolonged bradycardia, asystole, or both in patients with cardioinhibitory and non-cardioinhibitory vasovagal syncope (VVS). The study included 258 patients (mean age = 47.7 +/- 17.2 years; range 18-62; 147 females) with a history of VVS. They were divided among four groups, according to results of head-up tilt test (HUTT).

METHODS

All patients underwent standard HUTT, carotid sinus massage (CSM), and rapid transesophageal atrial pacing for evaluation of total sinus node recovery time (SNRT), and corrected sinus node recovery time (CNRT), resting and intrinsic heart rate (IHR), and Wenckebach point (WP). Values of SNRT > 1,500 ms, CNRT > 525 ms, WP < 130 bpm, and CSM-induced pause >3 seconds were considered abnormal.

RESULTS

SNRT, CNRT, and WP before and after pharmacological blockade, resting heart rate, and IHR did not differ significantly among the study groups. The prevalence of mild sinus node dysfunction (SND), decreased value of WP, and cardioinhibitory carotid sinus hypersensitivity was similar among all study groups.

CONCLUSIONS

The prevalence of mild SND, abnormal atrioventricular conduction, and carotid sinus hypersensitivity (CSH) was similar among patients with VVS regardless of the type of vasovagal reaction. SND and CSH do not seem to play an important role in the pathogenesis of cardioinhibitory vasovagal reaction.

The mechanisms determining the nucleolar-organizing regions inactivation of domestic horse chromosomes

Cytogenetic investigations of the nucleolar-organizing regions (NORs) show that there is variation in the transcriptional activity of rDNA in many organisms. As a consequence, genetic polymorphism of these regions has been detected. The aim of the present study was to evaluate the hypothetic genetic mechanisms determining the NORs polymorphism of the domestic horse chromosomes. Molecular cytogenetic analyses were carried out on Hucul horses and the following techniques were used: fluorescence in situ hybridization (FISH), telomere primed in situ synthesis (PRINS), in situ nick-translation with HpaII, silver staining (AgNOR) and C-banding technique (CBG). The obtained results suggest that variation in the number and size of silver deposits is related to the number of rDNA copies, DNA methylation and the localization of ribosomal DNA loci in telomeric regions. Moreover, we have found that chromosome pairs 28 and 31 are characterized by higher variation in the NORs number.

[Clinical significance of exercise-induced ST-segment elevation in lead aVR and V1 in patients with chronic stable angina pectoris and strongly positive exercise test results]

Electrocardiographic abnormalities in lead aVR and V1 are rarely analyzed on exercise electrocardiograms. Clinical significance of exercise-induced ST-segment changes in lead aVR and V1 during strongly positive electrocardiographic exercise test (EET) in patients with chronic stable angina pectoris remains unclear. The aim of the study was to assess the value of lead aVR and V1 on the exercise electrocardiogram for the detection of left main coronary artery stenosis (LMCAS) and its equivalent (LMCASE) in patients with chronic stable angina pectoris and the strongly positive EET result. The study group consisted of 118 consecutive patients (mean age 58.8 +/- 9.5 years, range 38-77 years), including 30 (25.4%) women. Patients were divided into three groups. In group I, 31 patients with ST elevation in lead aVR and V1, in group II 66 patients with isolated ST elevation in lead aVR, and in group III 21 patients without ST elevation in lead aVR, induced with exercise, were included. Coronary arteriography results were compared among these groups. In patients with isolated exercise-induced ST elevation in lead aVR, the prevalence of LMCAS was five times more frequent than in patients without lead aVR ST elevation (25.8% vs 4.8% p<0.05). There were no differences in the prevalence of LMCASE and multi-vessel coronary disease in the studied groups. In patients with LMCAS significant ST elevation in lead aVR during strongly positive EET were observed (0.25 +/- 0,4 mm vs 1.43 +/- 0.6 mm p = 0.003), whereas there were no significant exercise-induced electrocardiographic changes in lead V1 (0.61 +/- 0.6 mm vs 0.77 +/- 0.6 mm p = 0.08). Sensitivity of isolated exercise-induced ST elevation in lead aVR in detection of LMCAS was 85.0%, specificity - 50.0%, positive predictive value - 25.8%, negative predictive value - 94.2%, and total accuracy - 55.9%. Exercise-induced ST elevation in lead aVR on the strongly positive exercise ECG may detect LMCAS in patients with chronic stable angina pectoris.