Development of heparinized and hepatocyte growth factor-coated acellular scaffolds using porcine carotid arteries.

Tissue-engineered blood vessel substitutes have been developed due to the lack of suitable small-diameter vascular grafts. Xenogeneic extracellular matrix (ECM) scaffolds have the potential to provide an ideal source for off-the-shelf vascular grafts. In this study, porcine carotid arteries were used to develop ECM scaffolds by decellularization and coating with heparin and hepatocyte growth factor (HGF). After decellularization, cellular and nucleic materials were successfully removed with preservation of the main compositions (collagen, elastin, and basement membrane) of the native ECM. The ultimate tensile strength, suture strength, and burst pressure were significantly increased after cross-linking. Pore size distribution analysis revealed a porous structure within ECM scaffolds with a high distribution of pores larger than 10 µm. Heparinized scaffolds exhibited sustained release of heparin in vitro and showed potent anticoagulant activity by prolonging activated partial thromboplastin time. The scaffolds showed an enhanced HGF binding capacity as well as a constant release of HGF as a result of heparin modification. When implanted subcutaneously in rats, the modified scaffolds revealed good biocompatibility with enzyme degradation resistance, mitigated immune response, and anti-calcification. In conclusion, heparinized and HGF-coated acellular porcine carotid arteries may be a promising biological scaffold for tissue-engineered vascular grafts.

[Correlations between plaque characteristics and cerebral blood flow in patients with moderate to severe carotid stenosis using magnetic resonance vessel wall imaging].

OBJECTIVE: To investigate the correlations between carotid plaque characteristics and cerebral blood flow (CBF) in patients with unilateral moderate to severe carotid stenosis using high-resolution magnetic resonance imaging (HR-MRI) and 3D pseudo-continuous arterial spin labeling (3D pcASL). METHODS: A total of 43 patients with unilateral moderate to severe carotid stenosis were recruited. The degree of carotid stenosis, maximum wall thickness (Max WT) and normalized wall index (NWI) were measured using HR-MRI. The plaque characteristics were analyzed. Presence or absence of plaque components including intraplaque hemorrhage (IPH), lipid-rich necrotic nucleus (LRNC), calcification and ulcer were identified, and the grades of calcification and LRNC were recorded. CBF values within the region of interest representing the bilateral middle cerebral artery distribution were acquired using 3D pcASL. Paired sample t test was used to compare the differences of CBF values between the index side and the contralateral side. Spearman correlation analysis was conducted to evaluate the correlations of CBF values with the degree of carotid stenosis, Max WT and NWI. The differences of CBF values between the patients with or without IPH and ulcer were compared using Mann-Whitney U test. Different levels of calcification and LRNC were compared by Kruskal-Wallis test, respectively. RESULTS: The ave-rage degree of carotid stenosis at the index side was 77.30%±11.79%. The mean CBF value of the index side was (46.77±11.65) mL/(100 g·min), and that of the contralateral side was (49.92±9.95) mL/(100 g·min), and the difference was statistically significant (t=-2.474, P=0.017). The mean Max WT and NWI of the carotid plaques at the index side was (6.40±1.87) mm and 62.91%±8.87%, respectively. There were no significant correlations of CBF values with the degrees of stenosis, Max WT and NMI (P>0.05). Plaque composition analysis showed that the CBF values of the index side were different when there was calcification or not and the degrees of calcification were different (P=0.030), but there were no differences between the CBF values on the index sides with or without IPH, ulcer and LRNC. CONCLUSION: In patients with unilateral moderate to severe carotid stenosis, calcification might affect CBF perfusion. When there is no calcification, the plaque components need attention.

Urate crystal deposition is associated with inflammatory markers and carotid artery pathology in patients with intercritical gout: results from the NOR-Gout study.

BACKGROUND: Gout is of unknown reason associated with cardiovascular disease. Ultrasound is sensitive for detecting crystal deposition and plasma calprotectin is a sensitive inflammatory marker. This study explores the associations between crystal deposition, inflammation and carotid artery pathology. METHOD: A cross-sectional analysis of baseline assessments from the NOR-Gout study was undertaken. Crystal deposition was assessed by ultrasound (double contour, tophi, aggregates) and dual-energy CT (DECT) and laboratory assessments included plasma calprotectin. The carotid arteries were bilaterally examined for carotid intima-media thickness (cIMT) and presence of plaques. Spearman correlations, Mann-Whitney tests and linear regression analyses were used to explore associations between crystal deposition, inflammatory markers,and carotid pathology. RESULTS: 202 patients with intercritical gout (95.5% men, mean (SD) age 56.5 (13.8) years, disease duration 7.9 (7.7) years) were included. Calprotectin was correlated with all scores of crystal deposition by ultrasound (r=0.26-0.32, p<0.001) and DECT (r=0.15, p<0.05). cIMT was correlated with sum score aggregates (r=0.18-0.22, p<0.05). Patients with large tophi had higher levels of calprotectin as well as more frequent carotid plaque (p<0.05). CONCLUSIONS: Study findings point towards crystal deposition contributing to subclinical inflammation with subsequent vascular implications. However, future longitudinal studies are needed to confirm such causal relationships.

Comparison of zinc levels in the various biosubstrates of patients with unstable atherosclerotic plaque.

The article describes the content and comparative characteristics of zinc level in the hair, biopsies of carotid atherosclerotic plaques (AP) and serum in patients with carotid atherosclerosis. The highest concentration of zinc is found in hair compared to the AP and serum. Zinc levels is higher in AP than in the serum. It is noteworthy that the level of zinc in biopsies of unstable AP was lower compared to the level of zinc in hair.

Relationship between life-time exposure to ambient fine particulate matter and carotid artery intima-media thickness in Australian children aged 11-12 years.

Long-term exposure to air pollutants, especially particulates, in adulthood is related to cardiovascular diseases and vascular markers of atherosclerosis. However, whether vascular changes in children is related to exposure to air pollutants remains unknown. This study examined whether childhood exposure to air pollutants was related to a marker of cardiovascular risk, carotid intima-media thickness (CIMT) in children aged 11-12 years old. Longitudinal Study of Australian Children (LSAC) recruited parents and their children born in 2003-4. Among the participants, CheckPoint examination was conducted when the children were 11-12 years old. Ultrasound of the right carotid artery was performed using standardized protocols. Average and maximum far-wall CIMT, carotid artery distensibility, and elasticity were quantified using semiautomated software. Annual and life-time exposure to air pollutants was estimated using satellite-based land-use regression by residential postcodes. A total of 1063 children (50.4% girls) with CIMT data, serum cholesterol, and modeled estimates of NO2 and PM2.5 exposure for the period 2003 to 2015 were included. The average and maximum CIMT, carotid distensibility, and elasticity were 497 µm (standard deviation, SD 58), 580 µm (SD 44), 17.4% (SD 3.2), and 0.48%/mmHg (SD 0.09), respectively. The life-time average concentrations of PM2.5 and NO2 were 6.4 µg/m3 (SD 1.4) and 6.4 ppb (SD 2.4), respectively. Both average and maximum CIMT were significantly associated with average ambient PM2.5 concentration (average CIMT: +5.5 µm per µg/m3, 95% confidence interval, CI 2.4 to 8.5, and maximum CIMT: +4.9 µm per µg/m3, CI 2.3 to 7.6), estimated using linear regression, adjusting for potential confounders. CIMT was not significantly related to NO2 exposure. Carotid artery diameter, distensibility, and elasticity were not significantly associated with air pollutants. We conclude that life-time exposure to low levels of PM2.5 in children might have measurable adverse impacts on vascular structure by age 11-12 years.

Cerebral small vessel disease, systemic vascular characteristics and potential therapeutic targets.

INTRODUCTION: Cerebral small vessel disease (SVD) is prevalent in the elderly population and is associated with increased risk of dementia, stroke and disability. Currently there are no clear targets or strategies for the treatment of cerebral SVD. We set out to identify modifiable vascular treatment targets. PATIENTS AND METHODS: 112 participants with and without a history of CVD underwent macrovascular, microvascular and endothelial function tests and an MRI head scan. RESULTS: Increased carotid intima media thickness and carotid-femoral pulse wave velocity were associated with cerebral WMH (ß=1·1 p=0·001 and ß=1·66, p<0·0001 respectively). Adjusted cerebral resistance index (p=0·03) and brachial flow mediated dilation time to peak (p=0·001) were associated with the severity of cerebral WMH independent of age and sex. Post occlusive reactive hyperaemia time as a measure of microvascular reactivity was associated with WMH after adjustment for age and sex (p=0·03). Ankle Brachial Pressure Index and urinary albumin excretion rate predicted the severity of cerebral WMH (p=0·02 and 0·01 respectively). Age and hypertension were the most important risk factors for WMH severity (p< 0·0001). DISCUSSION: In addition to hypertension, microalbuminuria, arterial stiffness, vascular reactivity and cerebrovascular resistance could be potential treatment targets to halt the development or progression of cerebral SVD.

In vivo recellularization of xenogeneic vascular grafts decellularized with high hydrostatic pressure method in a porcine carotid arterial interpose model.

Autologous vascular grafts are widely used in revascularization surgeries for small caliber targets. However, the availability of autologous conduits might be limited due to prior surgeries or the quality of vessels. Xenogeneic decellularized vascular grafts from animals can potentially be a substitute of autologous vascular grafts. Decellularization with high hydrostatic pressure (HHP) is reported to highly preserve extracellular matrix (ECM), creating feasible conditions for recellularization and vascular remodeling after implantation. In the present study, we conducted xenogeneic implantation of HHP-decellularized bovine vascular grafts from dorsalis pedis arteries to porcine carotid arteries and posteriorly evaluated graft patency, ECM preservation and recellularization. Avoiding damage of the luminal surface of the grafts from drying significantly during the surgical procedure increased the graft patency at 4 weeks after implantation (P = 0.0079). After the technical improvement, all grafts (N = 5) were patent with mild stenosis due to intimal hyperplasia at 4 weeks after implantation. Neither aneurysmal change nor massive thrombosis was observed, even without administration of anticoagulants nor anti-platelet agents. Elastica van Gieson and Sirius-red stainings revealed fair preservation of ECM proteins including elastin and collagen after implantation. The luminal surface of the grafts were thoroughly covered with von Willebrand factor-positive endothelium. Scanning electron microscopy of the luminal surface of implanted grafts exhibited a cobblestone-like endothelial cell layer which is similar to native vascular endothelium. Recellularization of the tunica media with alpha-smooth muscle actin-positive smooth muscle cells was partly observed. Thus, we confirmed that HHP-decellularized grafts are feasible for xenogeneic implantation accompanied by recellularization by recipient cells.

Long-term exposure to air pollution and atherosclerosis in the carotid arteries in the Malmö diet and cancer cohort.

BACKGROUND: Long-term exposure to air pollution increases the risk of cardiovascular morbidity and mortality, but the mechanisms are not fully known. Current evidence suggests that air pollution exposure contributes to the development of atherosclerosis. There are few studies investigating associations between air pollution and carotid plaques, a well-known precursor of cardiovascular disease. METHODS: A Swedish population-based cohort (aged 45-64 years at recruitment) was randomly selected from the Malmö Diet and Cancer study between 1991 and 1994, of which 6103 participants underwent ultrasound examination of the right carotid artery to determine carotid plaque presence and carotid intima media thickness (CIMT). Participants were assigned individual residential air pollution exposure (source-specific PM2.5, PM10, NOx, BC) at recruitment from Gaussian dispersion models. Logistic and linear regression models, adjusted for potential confounders and cardiovascular risk factors, were used to investigate associations between air pollutants and prevalence of carotid plaques, and CIMT, respectively. RESULTS: The prevalence of carotid plaques was 35%. The mean levels of PM2.5 and PM10 at recruitment were 11 and 14 µg/m3, most of which was due to long range transport. The exposure contrast within the cohort was relatively low. PM2.5 exposure was associated with carotid plaques in a model including age and sex only (OR 1.10 (95% CI 1.01-1.20) per 1 µg/m3), but after adjustment for cardiovascular risk factors and socioeconomic status (SES) the association was weak and not significant (OR 1.05 (95% CI 0.96-1.16) per 1 µg/m3). The pattern was similar for PM10 and NOx exposure. Associations between air pollutants and plaques were slightly stronger for long-term residents and in younger participants with hypertension. There was no clear linear trend between air pollution exposure and plaque prevalence. Non-significant slightly positive associations were seen between air pollution exposures and CIMT. CONCLUSIONS: In this large, well-controlled cross-sectional study at low exposure levels we found no significant associations between air pollution exposures and subclinical atherosclerosis in the carotid arteries, after adjusting for cardiovascular risk factors and SES. Further epidemiological studies of air pollution and intermediate outcomes are needed to explain the link between air pollution and cardiovascular events.

Modification of decellularized vascular xenografts with 8-arm polyethylene glycol suppresses macrophage infiltration but maintains graft degradability.

Because acellular vascular xenografts induce an immunological reaction through macrophage infiltration, they are conventionally crosslinked with glutaraldehyde (GA). However, the GA crosslinking reaction inhibits not only the host immune reaction around the graft but also the graft's enzymatic degradability, which is one of the key characteristics of acellular grafts that allow them to be replaced by host tissue. In this study, we used an 8-arm polyethylene glycol (PEG) to successfully suppress macrophage infiltration, without eliminating graft degradation. Decellularized ostrich carotid arteries were modified with GA or N-hydroxysuccinimide-activated 8-arm PEG (8-arm PEG-NHS), which has a molecular weight of 17 kDa. To evaluate the enzymatic degradation in vitro, the graft was immersed in a collagenase solution for 12 hr. The 8-arm PEG-modified graft was degraded to the same extent as the unmodified graft, but the GA-modified graft was not degraded. The graft was transplanted into rat subcutaneous tissue for up to 8 weeks. Although CD68-positive cells accumulated in the unmodified graft, they did not infiltrate into either modified graft. However, the GA-modified grafts calcified, but the 8-arm PEG-modified graft did not calcify after transplantation. These data suggested that 8-arm PEG-NHS is a promising modification agent for biodegradable vascular xenografts, to suppress acute macrophage infiltration only.

Correlation and assessment of coronary artery luminal stenosis: Post-mortem computed tomography angiogram versus histopathology.

BACKGROUND: Post-mortem Computed Tomography (PMCT) allows non-invasive or minimally invasive detection of findings that may or may not be visible during conventional autopsy, however, it does not allow the investigator to draw any conclusions regarding patency of the vessel's lumen. To address this deficiency, Post-mortem Computed Tomography Angiography (PMCTA) utilizing different contrast media and techniques have been introduced with various studies looking at the correlation between PMCTA, autopsy (gross) findings and coronary artery histology in diagnosing coronary artery disease. OBJECTIVES: The aim of this study is to investigate the sensitivity and specificity of PMCTA in diagnosing coronary artery stenosis using water-based contrast media introduced though the vessels of the neck, compared to the gold standard of diagnosis i.e. gross and histological evaluation of the coronary artery. METHOD: This was a cross sectional study of 158 arterial sections involving 37 subjects recruited from the National Institute of Forensic Medicine (IPFN), Hospital Kuala Lumpur (HKL). An unenhanced PMCT was performed followed by PMCTA using water-based contrast media introduced though the vessels of the neck. Coronary artery stenosis was determined using multiplanar reconstructionD while the degree of stenosis was determined by calculating the percentage of luminal diameter divided by the diameter of the vessel internal elastic. RESULTS: The analysis of PMCTA and histopathology examinations revealed a sensitivity of 61.5%, specificity of 91.7%; positive predictive value (PPV) of 40.0% and negative predictive value (NPV) of 96.4%. CONCLUSION: PMCTA utilizing water-based contrast introduced though the vessels of the neck yielded similar results as other methods and techniques of PMCTA. We would therefore conclude that PMCTA utilizing this technique could be used to assess the degree of calcification and the presence of significant stenosis.

Decellularization, cross-linking and heparin immobilization of porcine carotid arteries for tissue engineering vascular grafts.

Tissue engineering vascular grafts (TEVGs) have the potential to replace small-diameter grafts in bypass surgery which is good news for patients with cardiovascular disease. Decellularized arteries can be ideal TEVGs because their natural three-dimensional structures support the migration of host cells and vascular remodeling. There are many methods for decellularization without a standard protocol. In this study, a combination of Triton X-100 and sodium dodecyl sulfate (SDS) were used to prepare decellularized arteries. However, decellularization may damage the biochemical and mechanical properties to some degree. We used the cross-linking agents N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) to improve mechanical properties and immobilize heparin to inhibit thrombogenesis. Histological analysis, scanning electron microscopy, biomechanical properties test, determination of immobilized heparin, active partial thrombin time assay, and subcutaneous embedding experiment were used to evaluate the efficiency of decellularization and the efficacy of heparinized cross-linked vascular scaffold. Results showed 1% Triton X-100 combined with 0.3% SDS can decellularize successfully. EDC and NHS cross-linking can improve the mechanical properties, reduce the inflammatory reaction and slow the degradation time. Heparin immobilized on the scaffolds can inhibit thrombogenesis effectively. This study indicated the heparinized cross-linked vascular scaffolds may be ideal scaffolds for TEVGs.

Plaque calcification is driven by different mechanisms of mineralization associated with specific cardiovascular risk factors.

BACKGROUND AND AIMS: The aim of this study was to investigate possible associations among markers of mineralization, plaque instability and the main risk factors of atherosclerosis. METHODS AND RESULTS: A Tissue MicroArray containing 52 samples of calcified carotid plaques from 52 symptomatic and asymptomatic patients were built. TMA serial sections were used to study the expression of inflammatory and mineralization markers (BMP-2, BMP-4, VDR, RANKL, Osteopontin, Sclerostin, ß-catenin and calmodulin) by immunohistochemistry. Our data clearly demonstrated the expression of mineralization markers in atheromatic plaques. Indeed, with the exception of RANKL, all investigated markers were expressed in at least 60% of cases. Specifically, multivariate analysis displayed significant associations between both the expression of BMP-2 and the presence of unstable plaques as well as between the expression of ß-catenin and the presence of stable plaques. We also found a significant inverse association between both a) the presence of hypertension and VDR and b) smoking habits and calmodulin expression. Finally, we noted a higher density of RANKL positive cells in plaques from diabetic patients as compared to non-diabetic ones and a significant positive association between hypertriglyceridemia and BMP-4 expression. CONCLUSION: Our results support the hypothesis that the process of atherosclerotic plaque calcification presents a number of similarities with the physiological processes that occur in bone, involving both osteoblasts- and osteoclasts-like arterial cells. Finally, the present study suggests that risk factors, such as hypertension, cigarette smoke and diabetes, can cause the destabilization of the atheromatic plaque acting on calcification process as well as inflammation.

Upregulation of miR-330-5p is associated with carotid plaque's stability by targeting Talin-1 in symptomatic carotid stenosis patients.

BACKGROUND: The aim of this study was to investigate the relationship between Talin-1 and stability of carotid atherosclerosis plaque and also find out the role of miRNA, as an upstream regulator, in regulating the expression level of Talin-1. METHODS: Human carotid plaques were obtained from 20 symptomatic carotid stenosis patients who underwent carotid endarterectomy (CEA) in our hospital between October 2014 and August 2017. Western blot analysis and immunohistochemistry was carried out to detect the distribution and expression level of Talin-1 in each plaque sample. The content of miRNAs in carotid plaque was decected by quantitative reverse transcription polymerase chain reaction (RT-qPCR), and the relative expression levels were calculated by 2-△△Ct method after the (cycle threshold) Ct value (power amplification knee point) was obtained. Dual-luciferase reporter assays were applied to verify the successful transfections. Finally, we compared all the groups with independent-samples t-test and one-way analysis of variance (ANOVA). RESULTS: Talin-1 was significantly downregulated in human unstable carotid plaque samples compared with stable carotid plaques (P < 0.05), and the distribution of Talin-1 was mainly found in the fibrous cap of carotid plaque. The overexpression of miRNA-330-5p was found in unstable carotid plaque, which significantly induced the inhibition of expression level of Talin-1. CONCLUSION: Upregulated miR-330-5p may lead to unstable carotid plaques by targeting Talin-1 in symptomatic carotid stenosis patients. This might be a new target for the treatment of atherosclerotic diseases through future studies.

Modern Concepts in Regenerative Therapy for Ischemic Stroke: From Stem Cells for Promoting Angiogenesis to 3D-Bioprinted Scaffolds Customized via Carotid Shear Stress Analysis.

Ischemic stroke is associated with a tremendous economic and societal burden, and only a few therapies are currently available for the treatment of this devastating disease. The main therapeutic approaches used nowadays for the treatment of ischemic brain injury aim to achieve reperfusion, neuroprotection and neurorecovery. Therapeutic angiogenesis also seems to represent a promising tool to improve the prognosis of cerebral ischemia. This review aims to present the modern concepts and the current status of regenerative therapy for ischemic stroke and discuss the main results of major clinical trials addressing the effectiveness of stem cell therapy for achieving neuroregeneration in ischemic stroke. At the same time, as a glimpse into the future, this article describes modern concepts for stroke prevention, such as the implantation of bioprinted scaffolds seeded with stem cells, whose 3D geometry is customized according to carotid shear stress.

Differences in Carotid Plaques Between Symptomatic Patients With and Without Diabetes Mellitus.

Objective- Diabetes mellitus is associated with high-risk atherosclerotic plaques. This study aimed to compare characteristics of carotid atherosclerotic plaques in symptomatic Chinese diabetic and nondiabetic patients using vessel wall magnetic resonance imaging. Approach and Results- Patients with cerebral ischemic symptoms in the anterior circulation and carotid atherosclerotic plaque determined by ultrasound were recruited from a cross-sectional, observational, multicenter study of CARE-II (Chinese Atherosclerosis Risk Evaluation). All patients underwent magnetic resonance imaging for carotid arteries. The morphological and compositional characteristics of carotid plaques were compared between diabetic and nondiabetic patients using linear (continuous variables) and logistic regression (binary variables). In a total of 584 recruited patients, 182 (31.2%) had diabetes mellitus. From the univariate analysis, diabetic patients had significantly greater mean wall area (33.7 versus 31.1 mm2; P=0.002), maximum wall thickness (3.2 versus 2.8 mm; P<0.001), and mean normalized wall index (43.8% versus 41.0%; P<0.001) and had significantly higher prevalence of calcification (51.6% versus 36.6%; P=0.001), lipid-rich necrotic core (77.5% versus 58.5%; P<0.001), and high-risk plaque (29.7% versus 19.9%; P=0.011) than nondiabetic patients. After adjusting for clinical characteristics, the differences in presence of calcification ( P=0.018) and lipid-rich necrotic core ( P=0.001) remained statistically significant. Conclusions- Symptomatic Chinese diabetic patients are more likely to have carotid plaques with calcification and lipid-rich necrotic core than nondiabetic patients, suggesting that diabetic patients may develop more severe atherosclerotic disease that should be accounted for in their clinical management.

Carotid Arterial Calcium Scoring Using Upper Airway Computed Tomography in Patients with Obstructive Sleep Apnea: Efficacy as a Clinical Predictor of Cerebrocardiovascular Disease.

OBJECTIVE: To evaluate the value of airway computed tomography (CT) in patients with obstructive sleep apnea (OSA) as a predictor of cerebrocardiovascular disease (CCVD) clinically, by quantitatively analyzing carotid arterial calcification (CarAC). MATERIALS AND METHODS: This study included 287 patients aged 40-80 years, who had undergone both polysomnography (PSG) and airway CT between March 2011 and October 2015. The carotid arterial calcium score (CarACS) was quantified using the modified Agatston method on each upper airway CT. The OSA severity was categorized as normal, mild, moderate, and severe using the PSG results. Clinical characteristics, comorbid diseases, and lipid profiles of all patients were analyzed, and the prevalence of CCVDs was investigated during the follow up period (52.2 ± 16.0 months). RESULTS: CCVD occurred in 27 patients (9.3%) at the end of follow-up, and the CCVD-present groups showed a significantly older mean age (57.5 years vs. 54.2 years), higher prevalence of hypertension (59% vs. 34%) and CarAC (51.9% vs. 20.8%), whereas sex, other comorbid diseases, and severity of OSA were not significantly different from the CCVD-absent group. A univariate analysis showed that age, hypertension, incidence of CarAC, and CarACS were risk factors for the occurrence of CCVD events. In a multivariate analysis, the incidence of CarAC was the only independent risk factor for CCVD. CONCLUSION: CarAC is an independent risk factor for CCVD, whereas the severity of OSA is not a contributory risk factor in patients with OSA. Therefore, additional analysis of CarACS based on airway CT scans may be useful for predicting CCVD.

Mass Spectrometric Imaging Reveals Temporal and Spatial Dynamics of Bioactive Lipids in Arteries Undergoing Restenosis.

Restenosis, or renarrowing of the arterial lumen, is a common recurrent disease following balloon angioplasty and stenting treatments for cardiovascular disease. A major technical barrier for deciphering restenotic mechanisms is the dynamic, spatial profiling of bioactive lipids in the arterial wall, especially in small animals. Here, applying matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI), we conducted the first lipidomic study of temporal-spatial profiling in a small animal model of angioplasty-induced restenosis. Cross sections were collected 3, 7, and 14 days after balloon angioplasty of rat carotid arteries. MALDI-MSI analyses showed that diacylglycerols (DAGs), signaling lipids associated with restenosis, and lysophosphatidylcholines (LysoPCs), whose function was uncharacterized in restenosis, dramatically increased at postangioplasty day 7 and day 14 in the neointimal layer of balloon-injured arteries compared to uninjured controls. In contrast, sphingomyelins (SMs) did not increase, but rather decreased at day 3, day 7, and day 14 in injured arteries versus the uninjured control arteries. These results revealed previously unexplored distinct temporal-spatial lipid dynamics in the restenotic arterial wall. Additionally, we employed time-of-flight secondary ion mass spectrometry (TOF-SIMS) tandem MS imaging for both molecular identification and imaging at high spatial resolution. These imaging modalities provide powerful tools for unraveling novel mechanisms of restenosis involving lipids or small signaling molecules.

Combination of freeze-thaw with detergents: A promising approach to the decellularization of porcine carotid arteries.

BACKGROUND: A tissue engineering technique based on use of the extracellular matrix (ECM) as a scaffold shows great potential for preparing small-caliber vascular grafts. Decellularization protocols are still not standardized for bioengineering. The effects of freeze-thaw cycles used for decellularization are unknown. OBJECTIVE: To evaluate the effects of freeze-thaw cycles on porcine carotid arteries during decellularization and to develop a promising protocol for preparing ECM scaffolds. METHODS: Porcine carotid arteries were decellularized with freeze-thaw cycles followed by three different chemical protocols. Histological analysis, scanning electron microscopy, mechanical tests and pore size measurement were performed to assess their effects on the ECM. RESULTS: The composition, structure, and mechanical properties were not significantly changed after freeze-thaw cycles, with the exception of endothelial cells loss. Freeze-thaw led to a porous structure within arteries. The use of Triton X-100 followed by sodium dodecyl sulfate (SDS) resulted in ECM scaffolds with well-preserved composition, structure, and mechanical properties, as well as with adequate porosity. CONCLUSIONS: As the initial step for decellularization, freeze-thaw had little impact on arteries. Decellularized porcine carotid arteries, prepared using freeze-thaw cycles followed by treatment with Triton X-100 and SDS, may serve as a promising biological scaffold as a tissue-engineered vascular graft.

Facile preparation of a controlled-release tubular scaffold for blood vessel implantation.

Salvianic acid-loaded mesoporous silica nanoparticles into gelatin/polyurethane bilayered small-diameter tubular scaffold were prepared by thermally induced phase separation (TIPS) and electrospinning. Mesoporous silica nanoparticles (MSNs) were selected as carriers to load salvianic acid (SAL). The SAL-loaded MSNs (SAL@MSNs) with an optimized SAL loading efficiency of 10% was initially dispersed in gelatin solution and under a vacuum freeze-drying process as an inner layer of vascular scaffolds. Then, poly(ester-urethane)urea (C-PEEUU) nanofibers were electrospun outside the SAL@MSNs/Gelatin vascular scaffold to strengthen the spongy matrix. The loaded SAL within the MSNs/Gelatin/C-PEEUU bilayered small-diameter tubular scaffold showed a sustained release profile and good mechanical properties. In addition, the drug-loaded composite scaffold showed no unfavorable effects on the adhesion and proliferation of endothelial cells. Moreover, no intimal hyperplasia and acute thrombosis was observed in the short-term implantation in rabbit's carotid artery. We believe the SAL@MSNs/Gelatin/C-PEEUU bilayered vascular scaffolds have promise for vascular tissue engineering applications.

Quantitative measurement of lipid rich plaque by coronary computed tomography angiography: A correlation of histology in sudden cardiac death.

BACKGROUND AND AIMS: Recent advancements in coronary computed tomography angiography (CCTA) have allowed for the quantitative measurement of high-risk lipid rich plaque. Determination of the optimal threshold for Hounsfield units (HU) by CCTA for identifying lipid rich plaque remains unknown. We aimed to validate reliable cut-points of HU for quantitative assessment of lipid rich plaque. METHODS: 8 post-mortem sudden coronary death hearts were evaluated with CCTA and histologic analysis. Quantitative plaque analysis was performed in histopathology images and lipid rich plaque area was defined as intra-plaque necrotic core area. CCTA images were analyzed for quantitative plaque measurement. Low attenuation plaque (LAP) was defined as any pixel < 30, 45, 60, 75, and 90 HU cut-offs within a coronary plaque. The area of LAP was calculated in each cross-section. RESULTS: Among 105 cross-sections, 37 (35.2%) cross-sectional histology images contained lipid rich plaque. Although the highest specificity for identifying lipid rich plaque was shown with <30 HU cut-off (88.2%), sensitivity (e.g. 55.6% for <75 HU, 16.2% for <30 HU) and negative predictive value (e.g. 75.9% for <75 HU, 65.9% for <30 HU) tended to increase with higher HU cut-offs. For quantitative measurement, <75 HU showed the highest correlation coefficient (0.292, p = 0.003) and no significant differences were observed between lipid rich plaque area and LAP area between histology and CT analysis (Histology: 0.34 ±â€¯0.73 mm2, QCT: 0.37 ±â€¯0.71 mm2, p = 0.701). CONCLUSIONS: LAP area by CCTA using a <75 HU cut-off value demonstrated high sensitivity and quantitative agreement with lipid rich plaque area by histology analysis.