Calcification of atherosclerotic plaques and assessment of their stability

Presented herein is a review of the literature concerning mechanisms of calcification of atherosclerotic plaques (ASP), showing molecular mechanisms of interaction of processes of calcification with the factors inducing instability of ASPs (anti-inflammatory cytokines, neoangiogenesis, increased level of matrix metalloproteinases, etc.), also describing the effect of the value of volume of scope of calcification on stability of ASPs, followed by discussing the problems related to the role of biominerals (hydroxyapatite calcium phosphate) and Mn2+ in calcification of ASPs and their impact upon stability of the plaque

Connection Between the Carotid Plaque Instability and Paramagnetic Properties of the Intrinsic Mn²⁺ Ions

© 2016, Springer Science+Business Media New York.The pulsed W-band (the microwave frequency of 94 GHz, magnetic field of 3.4 T) electron paramagnetic resonance (EPR) comparative studies of a series of 20 atherosclerotic plaques (AP) obtained during carotid endarterectomy in patients with atherosclerosis is presented. The AP stability was established by ultrasound angiography. In all of the obtained species EPR spectra due to the presence of Mn2+ ions in a crystal matrix of hydroxyapatites (HAp) is observed. The existence of HAp in plaque fragments is confirmed by X-ray diffraction analyses. The spectral parameters of Mn2+ are ascribed to two possible locations in the HAp constituent of the atherosclerotic plaques. The difference in the electronic relaxation times of T2e for Mn2+ ions in stable and unstable plaques is observed that can indicate the more homogeneous distribution of Mn2+ in stable plaques as compared to unstable species. The results can be potentially used for the understanding the mechanisms of pathological calcifications and AP stability

Paramagnetic Manganese in the Atherosclerotic Plaque of Carotid Arteries

© 2016 Yury Chelyshev et al.The search for adequate markers of atherosclerotic plaque (AP) instability in the context of assessment of the ischemic stroke risk in patients with atherosclerosis of the carotid arteries as well as for solid physical and chemical factors that are connected with the AP stability is extremely important. We investigate the inner lining of the carotid artery specimens from the male patients with atherosclerosis (27 patients, 42-64 years old) obtained during carotid endarterectomy by using different analytical tools including ultrasound angiography, X-ray analysis, immunological, histochemical analyses, and high-field (3.4 T) pulse electron paramagnetic resonance (EPR) at 94 GHz. No correlation between the stable and unstable APs in the sense of the calcification is revealed. In all of the investigated samples, the EPR spectra of manganese, namely, Mn2+ ions, are registered. Spectral and relaxation characteristics of Mn2+ ions are close to those obtained for the synthetic (nano) hydroxyapatite species but differ from each other for stable and unstable APs. This demonstrates that AP stability could be specified by the molecular organization of their hydroxyapatite components. The origin of the obtained differences and the possibility of using EPR of Mn2+ as an AP stability marker are discussed

Criteria for instability of atherosclerotic plaques in carotid arteries

The purpose of the study was to determine the criteria for instability of atherosclerotic plaques in carotid arteries with the use of improved and new diagnostic techniques. The study enrolled a total of 92 patients examined with the help of instrumental methods of diagnosis, including ultrasound triplex scanning, magnetic resonance imaging and multislice computed tomography. All patients were subjected to the operation of carotid endarterectomy in various standard modifications. The specimens of atherosclerotic plaques taken intraoperatively were examined with the help of morphological, immunofluorescent methods, electron paramagnetic resonance, electron microscopy. A multivariate logistic regression analysis demonstrated that the plaques with an area over 90 mm2 (OR 4.05; 95% CI 1.32-13.2; p=0.006), a volume of more than 0.6 cm3 (OR 2.72; 95% CI 1.05-9.58; p=0.04), and the JBA value of not less than 8 mm2 (OR 2.82; 95% CI 1.22-6.23; p=0.02) were statistically significant independent predictors of histologically verified unstable plaques. The results were compared to the findings of histological methods. In patients with the above mentioned ultrasonographic parameters, unstable plaques were encountered in 94% of cases. Immunofluorescent assay demonstrated a significant increase in the number of inflammatory markers (CD68+, CD36+ cells), as well as CD31+ cells as markers of neovasculogenesis in unstable plaques. According to the findings of electron paramagnetic resonance, bivalent manganese is a marker of plaque instability. Further studies will help reveal the mechanisms of plaque calcification. A decrease in the content of manganese correlated with an increase in the degree of plaque calcification (r =-0.69, p<0.01). This serves as indirect evidence of a destabilizing effect of calcification on plaque stability. It was demonstrated that ultrasound elastography makes it possible to significantly extend the capabilities of standard ultrasound examination in detecting instability of atherosclerotic plaques in carotid arteries

Criteria for instability of atherosclerotic plaques in carotid arteries

The purpose of the study was to determine the criteria for instability of atherosclerotic plaques in carotid arteries with the use of improved and new diagnostic techniques. The study enrolled a total of 92 patients examined with the help of instrumental methods of diagnosis, including ultrasound triplex scanning, magnetic resonance imaging and multislice computed tomography. All patients were subjected to the operation of carotid endarterectomy in various standard modifications. The specimens of atherosclerotic plaques taken intraoperatively were examined with the help of morphological, immunofluorescent methods, electron paramagnetic resonance, electron microscopy. A multivariate logistic regression analysis demonstrated that the plaques with an area over 90 mm2 (OR 4.05; 95% CI 1.32-13.2; p=0.006), a volume of more than 0.6 cm3 (OR 2.72; 95% CI 1.05-9.58; p=0.04), and the JBA value of not less than 8 mm2 (OR 2.82; 95% CI 1.22-6.23; p=0.02) were statistically significant independent predictors of histologically verified unstable plaques. The results were compared to the findings of histological methods. In patients with the above mentioned ultrasonographic parameters, unstable plaques were encountered in 94% of cases. Immunofluorescent assay demonstrated a significant increase in the number of inflammatory markers (CD68+, CD36+ cells), as well as CD31+ cells as markers of neovasculogenesis in unstable plaques. According to the findings of electron paramagnetic resonance, bivalent manganese is a marker of plaque instability. Further studies will help reveal the mechanisms of plaque calcification. A decrease in the content of manganese correlated with an increase in the degree of plaque calcification (r =-0.69, p<0.01). This serves as indirect evidence of a destabilizing effect of calcification on plaque stability. It was demonstrated that ultrasound elastography makes it possible to significantly extend the capabilities of standard ultrasound examination in detecting instability of atherosclerotic plaques in carotid arteries

Calcification of atherosclerotic plaques and assessment of their stability

Presented herein is a review of the literature concerning mechanisms of calcification of atherosclerotic plaques (ASP), showing molecular mechanisms of interaction of processes of calcification with the factors inducing instability of ASPs (anti-inflammatory cytokines, neoangiogenesis, increased level of matrix metalloproteinases, etc.), also describing the effect of the value of volume of scope of calcification on stability of ASPs, followed by discussing the problems related to the role of biominerals (hydroxyapatite calcium phosphate) and Mn2+ in calcification of ASPs and their impact upon stability of the plaque

Calcification of atherosclerotic plaques and assessment of their stability

Presented herein is a review of the literature concerning mechanisms of calcification of atherosclerotic plaques (ASP), showing molecular mechanisms of interaction of processes of calcification with the factors inducing instability of ASPs (anti-inflammatory cytokines, neoangiogenesis, increased level of matrix metalloproteinases, etc.), also describing the effect of the value of volume of scope of calcification on stability of ASPs, followed by discussing the problems related to the role of biominerals (hydroxyapatite calcium phosphate) and Mn2+ in calcification of ASPs and their impact upon stability of the plaque

Calcification of atherosclerotic plaques and assessment of their stability

Presented herein is a review of the literature concerning mechanisms of calcification of atherosclerotic plaques (ASP), showing molecular mechanisms of interaction of processes of calcification with the factors inducing instability of ASPs (anti-inflammatory cytokines, neoangiogenesis, increased level of matrix metalloproteinases, etc.), also describing the effect of the value of volume of scope of calcification on stability of ASPs, followed by discussing the problems related to the role of biominerals (hydroxyapatite calcium phosphate) and Mn2+ in calcification of ASPs and their impact upon stability of the plaque

Connection Between the Carotid Plaque Instability and Paramagnetic Properties of the Intrinsic Mn²⁺ Ions

© 2016, Springer Science+Business Media New York.The pulsed W-band (the microwave frequency of 94 GHz, magnetic field of 3.4 T) electron paramagnetic resonance (EPR) comparative studies of a series of 20 atherosclerotic plaques (AP) obtained during carotid endarterectomy in patients with atherosclerosis is presented. The AP stability was established by ultrasound angiography. In all of the obtained species EPR spectra due to the presence of Mn2+ ions in a crystal matrix of hydroxyapatites (HAp) is observed. The existence of HAp in plaque fragments is confirmed by X-ray diffraction analyses. The spectral parameters of Mn2+ are ascribed to two possible locations in the HAp constituent of the atherosclerotic plaques. The difference in the electronic relaxation times of T2e for Mn2+ ions in stable and unstable plaques is observed that can indicate the more homogeneous distribution of Mn2+ in stable plaques as compared to unstable species. The results can be potentially used for the understanding the mechanisms of pathological calcifications and AP stability

Connection Between the Carotid Plaque Instability and Paramagnetic Properties of the Intrinsic Mn²⁺ Ions

© 2016, Springer Science+Business Media New York.The pulsed W-band (the microwave frequency of 94 GHz, magnetic field of 3.4 T) electron paramagnetic resonance (EPR) comparative studies of a series of 20 atherosclerotic plaques (AP) obtained during carotid endarterectomy in patients with atherosclerosis is presented. The AP stability was established by ultrasound angiography. In all of the obtained species EPR spectra due to the presence of Mn2+ ions in a crystal matrix of hydroxyapatites (HAp) is observed. The existence of HAp in plaque fragments is confirmed by X-ray diffraction analyses. The spectral parameters of Mn2+ are ascribed to two possible locations in the HAp constituent of the atherosclerotic plaques. The difference in the electronic relaxation times of T2e for Mn2+ ions in stable and unstable plaques is observed that can indicate the more homogeneous distribution of Mn2+ in stable plaques as compared to unstable species. The results can be potentially used for the understanding the mechanisms of pathological calcifications and AP stability