Calcified Atherosclerotic Lesions Research Articles

Postmortem diagnosis of arterial atherosclerosis in autopsy, postmortem computed tomography and histopathological examinations in medico-legal aspect = Pośmiertna diagnostyka miażdżycy naczyń tętniczych w badaniach sekcyjnych, w pośmiertnym badaniu tomografią komputerową oraz w badaniach histopatologicznych w aspekcie medyczno-sądowym

The aim of this study is to provide a retrospective assessment of the possibility of determining the severity of atherosclerosis based on postmortem computed tomography (PMCT), autopsy protocols and histopathological examination results. In the first stage of the study, 200 cases were evaluated of persons over 40 years of age in whom postmortem computed tomography and autopsy were performed. In the second stage, the cases were divided into a study group (cardiovascular deaths) and a control group, as well as divided by age and, in addition to autopsy protocols and PMCT results, histopathological findings were evaluated. The results of stage I demonstrated that the best detection of atherosclerosis was in the advanced stage with a predominance of detection in PMCT. Atherosclerosis detection in autopsy was highest in the coronary arteries, aorta and cerebral arteries; while in PMCT it remained equal in all evaluated locations. Autopsy showed higher detection of advanced atherosclerotic lesions in the coronary arteries and aorta compared to PMCT. The results of stage II of the study revealed that attaching the results of the general histopathological examination to the retrospective evaluation does not provide an opportunity to increase the accuracy of the evaluation of atherosclerotic lesions. The results obtained indicate the need for prospective studies. Conclusions: autopsy allows macroscopic evaluation of a very broad spectrum of atherosclerotic lesions, but often without precise determination of their nature, and with limited localization; PMCT allows accurate and reproducible evaluation of calcified atherosclerotic lesions in large and medium-sized vessels, but is unsuitable for the evaluation of non-calcified lesions and small vessels; targeted histopathological examinations allow very accurate, but local assessment of atherosclerotic lesions.

Inhibition of vascular calcification by Compound Danshen Dripping Pill through multiple mechanisms

BackgroundVascular calcification refers to the abnormal accumulation of calcium in the walls of blood vessels and is a risk factor often overlooked in cardiovascular disease. However, there is currently no specific drug for treating vascular calcification. Compound Danshen Dripping Pill (CDDP) is widely used to treat cardiovascular diseases, but its effect on vascular calcification has not been reported. PurposeWe investigated the effects of CDDP on vascular calcification in ApoE−/− mice and in vitro and elucidated its mechanism of action. Study designFirstly, we found that CDDP has the potential to improve calcification based on network pharmacology analysis. Then, we performed the following experiments: in vivo, ApoE−/− mice were fed a high-fat diet randomly supplemented with CDDP for 16 weeks. Atherosclerosis and vascular calcification were determined. In vitro, human aortic smooth muscle cells (HASMCs), human umbilical vein endothelial cells (HUVECs), and human aortic endothelial cells (HAECs) were used to determine the mechanisms for CDDP-inhibited vascular calcification. ResultsIn this study, we observed that CDDP reduced intimal calcification in atherosclerotic lesions of ApoE-deficient mice fed a high-fat diet, as well as the calcification in cultured SMCs and ECs. Mechanistically, CDDP inhibited the Wnt/β-catenin pathway by up-regulating the expression of DKK1 and LRP6, which are upstream inhibitors of Wnt, leading to a reduction in the expression of osteoblastic transition markers (ALP, OPN, BMP2, and RUNX2). Furthermore, CDDP enhanced the secretion of DKK1, which plays a role in mediating EC-SMC crosstalk in calcification. Additionally, VC contributes to vascular aging by inhibiting Sirt1 and increasing senescence parameters (SA-β-gal, p21, and p16). However, CDDP reversed these changes by activating Sirt1. CDDP also reduced the levels of pro-inflammatory cytokines and the senescence-associated secretory phenotype in vivo and in vitro. ConclusionsOur study suggests that CDDP reduces vascular calcification by regulating the DKK1/LRP6/β-catenin signaling pathway in ECs/SMCs and interactions with the crosstalk of ECs and SMCs. It also reduces the senescence of ECs/SMCs, contributing to the Sirt1 activation, indicating CDDP's novel role in ameliorating vascular calcification.

Lysyl oxidase-dependent extracellular matrix crosslinking modulates calcification in atherosclerosis and aortic valve disease

Extracellular matrix (ECM) is an active player in cardiovascular calcification (CVC), a major public health issue with an unmet need for effective therapies. Lysyl oxidase (LOX) conditions ECM biomechanical properties; thus, we hypothesized that LOX might impact on mineral deposition in calcific aortic valve disease (CAVD) and atherosclerosis. LOX was upregulated in calcified valves from two cohorts of CAVD patients. Strong LOX immunostaining was detected surrounding calcified foci in calcified human valves and atherosclerotic lesions colocalizing with RUNX2 on valvular interstitial cells (VICs) or vascular smooth muscle cells (VSMCs). Both LOX secretion and organized collagen deposition were enhanced in calcifying VICs exposed to osteogenic media. β-aminopropionitrile (BAPN), an inhibitor of LOX, attenuated collagen deposition and calcification. VICs seeded onto decellularized matrices from BAPN-treated VICs calcified less than cells cultured onto control scaffolds; instead, VICs exposed to conditioned media from cells over-expressing LOX or cultured onto LOX-crosslinked matrices calcified more. Atherosclerosis was induced in WT and transgenic mice that overexpress LOX in VSMC (TgLOXVSMC) by AAV-PCSK9D374Y injection and high-fat feeding. In atherosclerosis-challenged TgLOXVSMC mice both atherosclerosis burden and calcification assessed by near-infrared fluorescence (NIRF) imaging were higher than in WT mice. These animals also exhibited larger calcified areas in atherosclerotic lesions from aortic arches and brachiocephalic arteries. Moreover, LOX transgenesis exacerbated plaque inflammation, and increased VSMC cellularity, the rate of RUNX2-positive cells and both connective tissue content and collagen cross-linking. Our findings highlight the relevance of LOX in CVC and postulate this enzyme as a potential therapeutic target for CVC.

Upregulation of NOR-1 in calcified human vascular tissues: impact on osteogenic differentiation and calcification

Cardiovascular calcification is a significant public health issue whose pathophysiology is not fully understood. NOR-1 regulates critical processes in cardiovascular remodeling, but its contribution to ectopic calcification is unknown. NOR-1 was overexpressed in human calcific aortic valves and calcified atherosclerotic lesions colocalizing with RUNX2, a factor essential for osteochondrogenic differentiation and calcification. NOR-1 and osteogenic markers were upregulated in calcifying human valvular interstitial cells (VICs) and human vascular smooth muscle cells (VSMCs). Gain- and loss-of-function approaches demonstrated that NOR-1 negatively modulates the expression of osteogenic genes relevant for the osteogenic transdifferentiation (RUNX2, IL-6, BMP2, and ALPL) and calcification of VICs. VSMCs from transgenic mice overexpressing NOR-1 in these cells (TgNOR-1VSMC) expressed lower basal levels of osteogenic genes (IL-6, BMP2, ALPL, OPN) than cells from WT littermates, and their upregulation by a high-phosphate osteogenic medium (OM) was completely prevented by NOR-1 transgenesis. Consistently, this was associated with a dramatic reduction in the calcification of both transgenic VSMCs and aortic rings from TgNOR-1VSMC mice exposed to OM. Atherosclerosis and calcification were induce in mice by the administration of AAV-PCSK9D374Y and a high-fat/high-cholesterol diet. Challenged-TgNOR-1VSMC mice exhibited decreased vascular expression of osteogenic markers, and both less atherosclerotic burden (assessed in whole aorta and lesion size in aortic arch and brachiocephalic artery) and less vascular calcification (assessed either by near-infrared fluorescence imaging or histological analysis) than WT mice. Our data indicate that NOR-1 negatively modulates the expression of genes critically involved in the osteogenic differentiation of VICs and VSMCs, thereby restraining ectopic cardiovascular calcification.

Calcification detection on upper extremity arteries: a comparison of ultrasonic and X-ray methods.

Vascular calcification (VC) has been observed in patients with hemodialysis, whereas few studies have investigated calcification in the upper extremity vasculature. Both ultrasound and X-ray are used to investigate the calcification of arteries in patients. However, there is a lack of data on the consistency between these two methods. The aim of this study was to investigate the occurrence of VC in the radial and ulnar arteries of hemodialysis patients and investigate the detection consistency in VC between ultrasound and X-ray. Ultrasound and X-ray examinations were performed in the radial and ulnar arteries of both the left and right upper extremities of 40 patients on hemodialysis. The calcification status of arteries was evaluated by the calcification index from ultrasound and X-ray respectively. Clinical variables of patients were collected from all the involved patients. Of the 40 patients, VC was detected in 31 patients by ultrasound, while X-ray detected VC in 22 patients. Compared to ultrasound assessment, X-ray assessment was 73.21% sensitive but only 66.35% specific with a positive predictive value of 53.95% for detecting calcifications in the radial or ulnar artery. The level of agreement between ultrasound and X-ray results was fair. In addition, our data showed that more ulnar arteries had VCs than the corresponding radial arteries. Ultrasound is more sensitive in detecting the presence of calcified atherosclerotic lesions. Ultrasound and X-ray exhibited fair consistency. Ultrasound screening for upper extremity radial and ulnar arteries in hemodialysis patients may deserve attention to explore its clinical significance.

GSK3β Inhibition Ameliorates Atherosclerotic Calcification.

Endothelial-mesenchymal transition (EndMT) drives endothelium to contribute to atherosclerotic calcification. In a previous study, we showed that glycogen synthase kinase-3β (GSK3β) inhibition induced β-catenin and reduced mothers against DPP homolog 1 (SMAD1) in order to redirect osteoblast-like cells towards endothelial lineage, thereby reducing vascular calcification in Matrix Gla Protein (Mgp) deficiency and diabetic Ins2Akita/wt mice. Here, we report that GSK3β inhibition or endothelial-specific deletion of GSK3β reduces atherosclerotic calcification. We also find that alterations in β-catenin and SMAD1 induced by GSK3β inhibition in the aortas of Apoe-/- mice are similar to Mgp-/- mice. Together, our results suggest that GSK3β inhibition reduces vascular calcification in atherosclerotic lesions through a similar mechanism to that in Mgp-/- mice.

Neutrophil and lymphocyte count as predictors of the location of calcific coronary lesions in patients treated with rotational atherectomy.

The role of immune system activation in development and progression of atherosclerotic plaques has been postulated. Previous studies on inflammation have focused on the severity of coronary disease, the risk of acute coronary syndrome, and the prediction of outcomes based on hematological indices obtained from whole blood count analysis. To analyze simple data of the whole blood count in relation to the location of calcified atherosclerotic lesions in patients treated with coronary rotational atherectomy (RA). Eighty-one patients (57 (70%) males, mean (SD) age of 70.4 ±8 years) who underwent RA were enrolled in the study. The study group was divided into two subgroups depending on the proximal (group 1) and non-proximal (group 2) location of the culprit lesions in coronary arteries. The angiographic results were compared with demographic and clinical data and whole blood count analysis. The multivariable analysis revealed the predictive value of low neutrophil (OR = 0.75, 95% CI: 0.58-0.97, p = 0.030) and lymphocyte counts (OR = 0.27, 95% CI: 0.11-0.68, p = 0.005) for the proximal location of the culprit lesions. In the ROC analysis, combined neutrophil and lymphocyte counts showed the best prediction of proximal location, with the area under the curve of 0.747 (p < 0.001), yielding a sensitivity of 79.07% and specificity of 73.68%. The lower neutrophil and lymphocyte counts in peripheral blood count analysis may be more representative of proximal calcified coronary lesions. The relationship between neutrophil and lymphocyte blood count and calcific atherosclerotic plaque location can indicate the inflammatory background of epicardial atheroma formation and distribution.

1066 THE USEFULNESS OF CEREBRAL PROTECTION DURING TAVR: A METANALYSIS

Abstract Introduction although transcatheter aortic valve replacement (TAVR) represents a milestone in the treatment of degenerative aortic stenosis, stroke remains an important complication compared to surgical aortic valve replacement (SAVR). Multiple magnetic resonance imaging (MRI) studies demonstrated a substantial rate of new cerebral ischemic lesions after TAVR. In order to avoid debris passage into the circulation and to prevent procedure-related embolic stroke, cerebral embolic protection (CEP) devices were developed. However, their safety and efficacy remain controversial. Very recently, new studies provided additional evidence on this topic. Aim to assess the entire body of evidence from randomized controlled studies about neurological outcomes after TAVR. Materials and Methods a systematic meta-analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched MEDLINE, Scopus, and Google Scholar for randomized controlled studies. The following keywords were used for the search: “transcatheter aortic valve implantation” or “stroke prevention” or “embolic protection” and “cerebral protection”. Study groups were defined as a the “CEP group” and the “control group”. Non-randomized studies reporting outcomes with cerebral embolic protection (CEP) during TAVR were excluded to reduce the selection and confounding bias of observational pilot studies. The primary outcome was post-procedural stroke. Secondary outcomes included total lesion volume on MRI and new ischemic lesions on MRI. Results nine trials including 4077 patients were eligible for analysis and included to the meta-analysis. Of those, 2203 patients were randomized to cerebral embolic protection and 1874 patients to control group. Despite the rate of post-procedural stroke was higher in the CEP arm (2.27%) compared to the control arm (2.87%, p&amp;lt;0.001), the use of cerebral embolic protection was not associated with a significantly lower risk of stroke (OR=0.82, 95% CI 0.59-1.15; p=0.255). Cumulative meta-analysis revealed a trend towards a lower impact on stroke prevention with more recent trials. Conclusions use of cerebral embolic protection devices during TAVR is a safe procedure. However, the current outline of results from all randomized controlled trials available does not support its routine use, as no significant reduction of stroke risk was evident. The use of these devices might be considered in selected high-risk patients, such as in the setting of heavy calcified cusps or atherosclerotic aortic lesions.

TXNIP Suppresses the Osteochondrogenic Switch of Vascular Smooth Muscle Cells in Atherosclerosis.

The osteochondrogenic switch of vascular smooth muscle cells (VSMCs) is a pivotal cellular process in atherosclerotic calcification. However, the exact molecular mechanism of the osteochondrogenic transition of VSMCs remains to be elucidated. Here, we explore the regulatory role of TXNIP (thioredoxin-interacting protein) in the phenotypical transitioning of VSMCs toward osteochondrogenic cells responsible for atherosclerotic calcification. The atherosclerotic phenotypes of Txnip-/- mice were analyzed in combination with single-cell RNA-sequencing. The atherosclerotic phenotypes of Tagln-Cre; Txnipflox/flox mice (smooth muscle cell-specific Txnip ablation model), and the mice transplanted with the bone marrow of Txnip-/- mice were analyzed. Public single-cell RNA-sequencing dataset (GSE159677) was reanalyzed to define the gene expression of TXNIP in human calcified atherosclerotic plaques. The effect of TXNIP suppression on the osteochondrogenic phenotypic changes in primary aortic VSMCs was analyzed. Atherosclerotic lesions of Txnip-/- mice presented significantly increased calcification and deposition of collagen content. Subsequent single-cell RNA-sequencing analysis identified the modulated VSMC and osteochondrogenic clusters, which were VSMC-derived populations. The osteochondrogenic cluster was markedly expanded in Txnip-/- mice. The pathway analysis of the VSMC-derived cells revealed enrichment of bone- and cartilage-formation-related pathways and bone morphogenetic protein signaling in Txnip-/- mice. Reanalyzing public single-cell RNA-sequencing dataset revealed that TXNIP was downregulated in the modulated VSMC and osteochondrogenic clusters of human calcified atherosclerotic lesions. Tagln-Cre; Txnipflox/flox mice recapitulated the calcification and collagen-rich atherosclerotic phenotypes of Txnip-/- mice, whereas the hematopoietic deficiency of TXNIP did not affect the lesion phenotype. Suppression of TXNIP in cultured VSMCs accelerates osteodifferentiation and upregulates bone morphogenetic protein signaling. Treatment with the bone morphogenetic protein signaling inhibitor K02288 abrogated the effect of TXNIP suppression on osteodifferentiation. Our results suggest that TXNIP is a novel regulator of atherosclerotic calcification by suppressing bone morphogenetic protein signaling to inhibit the transition of VSMCs toward an osteochondrogenic phenotype.

Arginase-1 Deletion in Erythrocytes Promotes Vascular Calcification via Enhanced GSNOR (S-Nitrosoglutathione Reductase) Expression and NO Signaling in Smooth Muscle Cells.

Erythrocytes (red blood cells) participate in the control of vascular NO bioavailability. The purpose of this study was to determine whether and how genetic deletion of ARG1 (arginase-1) affects vascular smooth muscle cell NO signaling, osteoblastic differentiation, and atherosclerotic lesion calcification. Atherosclerosis-prone mice with conditional, erythrocyte-restricted deletion of ARG1 (apoE-/- red blood cell.ARG1 knockout) were generated and vascular calcification studied using molecular imaging of the osteogenic activity agent OsteoSense, Alizarin staining or immunohistochemistry, qPCR of osteogenic markers and ex vivo assays. Atherosclerotic lesion size at the aortic root did not differ, but calcification was significantly more pronounced in apoE-/- mice lacking erythrocyte ARG1. Incubation of murine and human VSMCs with lysed erythrocyte membranes from apoE-/- red blood cell. ARG1-knockout mice accelerated their osteogenic differentiation, and mRNA transcripts of osteogenic markers decreased following NO scavenging. In addition to NO signaling via sGC (soluble guanylyl cyclase), overexpression of GSNOR (S-nitrosoglutathione reductase) enhanced degradation of S-nitrosoglutathione to glutathione and reduced protein S-nitrosation of HSP (heat shock protein)-70 were identified as potential mechanisms of vascular smooth muscle cell calcification in mice lacking ARG1 in erythrocytes, and calcium phosphate deposition was enhanced by heat shock and prevented by GSNOR inhibition. Messenger RNA levels of enzymes metabolizing the arginase products L-ornithine and L-proline also were elevated in VSMCs, paralleled by increased proliferation, myofibroblast marker and collagen type 1 expression. Our findings support an important role of erythrocyte ARG1 for NO bioavailability and L-arginine metabolism in VSMCs, which controls atherosclerotic lesion composition and calcification.

Biomolecules Orchestrating Cardiovascular Calcification.

Vascular calcification, once considered a degenerative, end-stage, and inevitable condition, is now recognized as a complex process regulated in a manner similar to skeletal bone at the molecular and cellular levels. Since the initial discovery of bone morphogenetic protein in calcified human atherosclerotic lesions, decades of research have now led to the recognition that the regulatory mechanisms and the biomolecules that control cardiovascular calcification overlap with those controlling skeletal mineralization. In this review, we focus on key biomolecules driving the ectopic calcification in the circulation and their regulation by metabolic, hormonal, and inflammatory stimuli. Although calcium deposits in the vessel wall introduce rupture stress at their edges facing applied tensile stress, they simultaneously reduce rupture stress at the orthogonal edges, leaving the net risk of plaque rupture and consequent cardiac events depending on local material strength. A clinically important consequence of the shared mechanisms between the vascular and bone tissues is that therapeutic agents designed to inhibit vascular calcification may adversely affect skeletal mineralization and vice versa. Thus, it is essential to consider both systems when developing therapeutic strategies.

Abstract P164: Pronethalol Reduces Sox2 To Ameliorate Vascular Calcification

Vascular calcification is present in most people over 60 years of age and results in severe complications that increase all-cause mortality of cardiovascular disease, diabetes mellitus and chronic kidney disease. Previous studies demonstrated that endothelial induction of SRY (sex determining region Y)-box 2 (Sox2) triggered endothelial-mesenchymal transitions (EndMTs) and drove endothelial cells (ECs) towards osteoblastic differentiation. The excess Sox2 induced mesenchymal markers and promoted ECs to acquire mesenchymal potential and undergo osteogenic differentiation. Recently, we reported that beta-adrenergic receptor antagonists (beta-blockers) decreased Sox2 expression in cerebrovascular endothelium and limited arteriovenous malformations. In this study, we hypothesize that the beta-blockers suppress Sox2 also in arterial endothelium to limit vascular calcification. To test this hypothesis, we used the Mgp -/- mouse model, where the elastic arteries start to calcify at 1-2 weeks of age and exhibit severe calcification at 4 weeks of age. We treated Mgp -/- mice with pronethalol for two weeks starting at 2 weeks of age and revealed that the pronethalol treatment significantly ameliorated the aortic calcification in Mgp -/- aortas. To examine the time-course of the pronethalol effect on calcification, we started the pronethalol treatment at three different time points, at 1, 2 and 3 weeks of age. The treatments all ended at 5 weeks of age. The results showed that the total aortic calcium was immediately reduced if the pronethalol was started at 1 or 2 weeks of age and was maintained at low levels as the treatment continued. When the treatment was started at 3 weeks of age, it still reduced the aortic calcium but to a lesser degree. To determine if pronethalol limits vascular calcification also in atherosclerosis and diabetes, we treated Apoe -/- mice and Ins2 Akita/+ mice with pronethalol. Aortic calcium and histology showed that pronethalol reduced the atherosclerotic lesion calcification and decreased the calcification in Ins2 Akita/+ mice. Together, the results suggest that the beta-blocker pronethalol reduces Sox2 expression in the arterial endothelium, thereby limiting EndMTs and vascular calcification.

Endovascular treatment of calcific lesions of the common femoral artery using atherectomy device associated with scoring balloon angioplasty in diabetic patients with high "major amputation" risk.

To investigate the outcomes of patients with calcific lesions in the common femoral artery undergoing endovascular procedures with atherectomy device and scoring balloon angioplasty combined with treatment of steno-occlusive disease of the remaining arterial districts of the lower limb. Between January 2015 and December 2018, 11 diabetic patients at high risk for "major amputation", with calcific lesions of the common femoral artery and ischemic ulcers requiring endovascular treatment were retrospectively evaluated. Technical success was defined as revascularization of the common femoral artery with a residual stenosis lower than 30%. Primary endpoints were an immediate increase of perilesional transcutaneous oxygen pressure (TCPO2) > 40 mmHg, ulcerative lesions improvement up to healing or skin flaps re-epithelialization after minor amputation, limb rescue with rejected major amputation, and resolution of rest pain if present. The success rate of the revascularization procedures was 100%. No patient underwent surgical conversion. One case of peri-operative bleeding at the brachial access site was observed. There were no cases of arterial dissection or undesired distal embolization. The average baseline value of perilesional TCPO2 was 21.8 ± 9.2 mmHg. The mean TCPO2 value was 57.4 ± 7.2 mmHg three days after the procedure (P < 0.05), and 51.2 ± 9.8 mmHg 15 days after (P < 0.05). Minor amputations were performed in five patients with advanced ulcerative lesions. No major amputations were performed in the follow-up period. At 14 months follow-up, one patient developed new occlusion of the CFA for extension from the external iliac artery and underwent a new endovascular procedure. We observed an overall primary patency rate of 91% and a primary assisted patency rate of 100% in our 18-month follow-up. Endovascular approach for severely calcified atherosclerotic lesions of the common femoral artery seems to represent a valid therapeutic option associated with promising results in terms of clinical outcome and low complication rates.

Feasibility of intravascular lithotripsy for calcific coronary lesions: A multi-institutional experience.

We sought to determine the safety and performance of intravascular lithotripsy in the treatment of severe calcified atherosclerotic lesions. The modification of severe calcified atherosclerotic lesions with noncompliant or specialty balloons, as well as orbital or rotational atherectomy has limitations and may be ineffective, increasing the risk of periprocedural complications and worsening long-term results. Intravascular lithotripsy has recently been shown to be a safe and feasible alternative to the above methods. All consecutive patients treated with Shockwave Medical Intravascular Lithotripsy (S-IVL) between May 2019 and June 2020 were included in current analysis. Device safety and efficacy were the critical endpoints of the study. The primary safety endpoint was 30-day major adverse cardiac events (MACE). In turn, device and clinical success were the primary performance endpoints. In total, 46 patients undergoing percutaneous coronary intervention were treated with S-IVL before stent deployment (65% male; age, 71 ± 7 years). Device success was achieved in 45 (97.8%) patients with reduction of diameter stenosis from 80% to 5.2% with an acute gain of 2.5 mm. Clinical success was demonstrated in 95.6% of cases. During the 30-day follow-up, one sudden death was recorded, regarded as probable subacute stent thrombosis. During 6-month follow up one target lesion and target vessel revascularizations occurred. The rate of MACE after 6month was 6.2%. S-IVL appears to be a safe and effective treatment modality in coronary calcium modification to optimize stent expansion. In selected cases this device obviates the need for more complex lesion preparation strategies such as atherectomy.

Optimized High Quality DNA Extraction from Formalin-Fixed Paraffin-Embedded Human Atherosclerotic Lesions

Formalin-fixed paraffin-embedded (FFPE) tissues represent a valuable source for molecular analyses and clinical genomic studies. These tissues are often poor in cells or difficult to process. Therefore, nucleic acids need to be carefully isolated. In recent years, various methods for DNA isolation have been established for tissues from many diseases, mostly cancer. Unfortunately, genomic DNA extracted from FFPE tissues is highly degraded due to the cross-linking between nucleic acid strands and proteins, as well as random breakings in sequence. Therefore, DNA quality from these samples is markedly reduced, making it a challenge for further molecular downstream analyses. Other problems with difficult tissues are, for example, the lack of cells in calcified human atherosclerotic lesions and fatty tissue, small skin biopsies, and consequently low availability of the desired nucleic acids as it is also the case in old or fixed tissues. In our laboratories, we have established a method for DNA extraction from formalin-fixed atherosclerotic lesions, using a semi-automated isolation system. We compared this method to other commercially available extraction protocols and focused on further downstream analyses. Purity and concentration of the DNA were measured by spectrometry and fluorometry. The degree of fragmentation and overall quality were assessed. The highest DNA quantity and quality was obtained with the modified blood DNA protocol for the automated extraction system, instead of the commercial FFPE protocol. With this step-by-step protocol, DNA yields from FFPE samples were in average four times higher and fewer specimens failed the extraction process, which is critical when dealing with small-vessel biopsies. Amplicon sizes from 200-800 bp could be detected by PCR. This study shows that although DNA obtained from our FFPE tissue is highly fragmented, it can still be used for successful amplification and sequencing of shorter products. In conclusion, in our hands, the automated technology appears to be the best system for DNA extraction, especially for small FFPE tissue specimen.

ERK1/2 inhibition reduces vascular calcification by activating miR-126-3p-DKK1/LRP6 pathway.

Rationale: Vascular microcalcification increases the risk of rupture of vulnerable atherosclerotic lesions. Inhibition of ERK1/2 reduces atherosclerosis in animal models while its role in vascular calcification and the underlying mechanisms remains incompletely understood.Methods: Levels of activated ERK1/2, DKK1, LRP6 and BMP2 in human calcific aortic valves were determined. ApoE deficient mice received ERK1/2 inhibitor (U0126) treatment, followed by determination of atherosclerosis, calcification and miR-126-3p production. C57BL/6J mice were used to determine the effect of U0126 on Vitamin D3 (VD3)-induced medial arterial calcification. HUVECs, HAECs and HASMCs were used to determine the effects of ERK1/2 inhibitor or siRNA on SMC calcification and the involved mechanisms.Results: We observed the calcification in human aortic valves was positively correlated to ERK1/2 activity. At cellular and animal levels, U0126 reduced intimal calcification in atherosclerotic lesions of high-fat diet-fed apoE deficient mice, medial arterial calcification in VD3-treated C57BL/6J mice, and calcification in cultured SMCs and arterial rings. The reduction of calcification was attributed to ERK1/2 inhibition-reduced expression of ALP, BMP2 and RUNX2 by activating DKK1 and LRP6 expression, and consequently inactivating both canonical and non-canonical Wnt signaling pathways in SMCs. Furthermore, we determined ERK1/2 inhibition activated miR-126-3p production by facilitating its maturation through activation of AMPKα-mediated p53 phosphorylation, and the activated miR-126-3p from ECs and SMCs played a key role in anti-vascular calcification actions of ERK1/2 inhibition.Conclusions: Our study demonstrates that activation of miR-126-3p production in ECs/SMCs and interactions between ECs and SMCs play an important role in reduction of vascular calcification by ERK1/2 inhibition.

A novel role of FKN/CX3CR1 in promoting osteogenic transformation of VSMCs and atherosclerotic calcification

Fractalkine (FKN) and its specific receptor CX3CR1 play a critical role in the pathogenesis of atherosclerosis including recruitment of vascular cells and the development of inflammation. However, its contribution to regulating the development of atherosclerotic calcification has not been well documented. Osteogenic transformation of vascular smooth muscle cells (VSMCs) is critical in the development of calcification in atherosclerotic lesions. In this study, for the first time, we evaluated the effect of FKN/CX3CR1 on the progression of VSMCs calcification and defined molecular signaling that is operative in the FKN/CX3CR1-induced osteogenic transformation of VSMCs. We found that high-fat diet induced atherosclerotic calcification in vivo was markedly inhibited in the Apolipoprotein E (ApoE) and CX3CR1 deficient (ApoE−/−/CX3CR1−/−) mice compared with their control littermates. FKN and CX3CR1 were both expressed in VSMCs and up-regulated by oxidized low-density lipoprotein (ox-LDL). FKN/CX3CR1 promoted the expression of osteogenic markers, including osteopontin (OPN), bone morphogenetic protein (BMP)-2 and alkaline phosphatase (ALP) and decreased VSMCs markers, including smooth muscle (SM) α-actin and SM22-α in a dose-dependent manner. The essential role of FKN/CX3CR1 in VSMCs calcification was further confirmed by lentivirus-mediated knockdown or overexpression of CX3CR1 blocked or accelerated osteogenic transformation of VSMCs. This response was associated with reciprocal up- and down-regulation of osteogenic factor, runt-related transcription factor 2 (RUNX2), transcription factors in osteoclast differentiation, receptor activator of nuclear factor-κB (RANK), RANK ligand (RNAKL) and osteoprotegerin (OPG), respectively. Inhibition of FKN/CX3CR1-activated Jak2/Stat3 signaling by the Jak/Stat inhibitor AG490 blocked osteogenic transformation of VSMCs and RUNX2 induction concurrently. Taken together, our data uncovered novel roles of FKN/CX3CR1 in promoting VSMC osteogenic transformation and atherosclerotic calcification by activating RUNX2 through Jak2/Stat3 signaling pathway and suppressing OPG. Our findings suggest that targeting FKN/CX3CR1 may provide new strategies for the prevention and treatment of atherosclerotic calcification.

Hyperhomocysteinemia induces vascular calcification by activating the transcription factor RUNX2 via Krüppel-like factor 4 up-regulation in mice

One of the main characteristics of atherosclerosis is vascular calcification, which is linked to adverse cardiovascular events. Increased homocysteine (Hcy), a feature of hyperhomocysteinemia, is correlated with advanced vascular calcification and phenotypic switching of vascular smooth muscle cells (VSMCs). Oxidative stress and high phosphate levels also induce VSMC calcification, suggesting that the Krüppel-like factor 4 (KLF4) signaling pathway may also contribute to vascular calcification. In this study, we investigated this possibility and the role and mechanisms of Hcy in vascular calcification. We found that in atherosclerotic apolipoprotein E-deficient (ApoE-/-) mice, Hcy significantly increases vascular calcification in vivo, as well as VSMC calcification in vitro Of note, the Hcy-induced VSMC calcification was correlated with elevated KLF4 levels. Hcy promoted KLF4 expression in calcified atherosclerotic lesions in vivo and in calcified VSMCs in vitro shRNA-mediated KLF4 knockdown blocked the Hcy-induced up-regulation of runt-related transcription factor 2 (RUNX2) and VSMC calcification. RUNX2 inhibition abolished Hcy-induced VSMC calcification. Using ChIP analysis, we demonstrate that KLF4 interacts with RUNX2, an interaction promoted by Hcy stimulation. Our experiments also revealed that the KLF4 knockdown attenuates Hcy-induced RUNX2 transactivity, indicating that KLF4 is important in modulating RUNX2 transactivity. These findings support a role for Hcy in regulating vascular calcification through a KLF4-RUNX2 interaction and indicate that Hcy-induced, enhanced RUNX2 transactivity increases VSMC calcification. These insights reveal possible opportunities for developing interventions that prevent or manage vascular calcification.

Tackling endothelium remodeling in cardiovascular disease

Endothelial dysfunction is considered an early marker of atherosclerosis. Herein, we address the molecular mechanisms affecting endothelium remodeling in disease. Vascular calcification is highly prevalent in patients with ischemic cardiovascular disease, cerebrovascular disorder, and renal failure, being a common feature in aging, diabetes, dyslipidemia, abnormal valve biomechanics, end-stage renal disease and atherosclerosis, a major cause of mortality and morbidity. Oxidative stress promotes calcification of vascular smooth muscle cells (SMC) by increasing osteogenic transcription factors expression and activity in atherosclerotic plaques. Various markers of osteogenic differentiation are expressed by SMC in calcified atherosclerotic lesions. Interestingly, decreased levels of some bone factors and microRNAs accelerate vascular calcification and injured tissue regeneration. Another key player in endothelial remodeling is amino acids metabolism. Branched-chain amino acids are catabolized in several nonhepatic tissues including cardiac muscle. Immune activation and inflammation in cardiovascular disease patients associate with higher phenylalanine/tyrosine ratios. Understanding the whole process that underlies endothelium dysfunction is of paramount importance for the development of new therapeutic approaches.

How to deal with calcium in the superficial femoral artery.

Despite the continuous evolution of endovascular therapy, severe calcification remains a major issue for the minimally invasive treatment of superficial femoral artery (SFA) disease. The presence of calcium might negatively affect both the crossing of peripheral lesions and outcomes of all available treatment modalities and is therefore associated with unfavorable acute and long-term results. This manuscript summarizes the challenges raised from severe calcified atherosclerotic lesions and presents the outcomes of the various endovascular modalities in the treatment of calcified SFA disease.