Plaque Evaluation by Ultrasound and Transcriptomics Reveals BCLAF1 as a Regulator of Smooth Muscle Cell Lipid Transdifferentiation in Atherosclerosis.

BACKGROUND: Understanding the processes behind carotid plaque instability is necessary to develop methods for identification of patients and lesions with stroke risk. Here, we investigated molecular signatures in human plaques stratified by echogenicity as assessed by duplex ultrasound. METHODS: Lesion echogenicity was correlated to microarray gene expression profiles from carotid endarterectomies (n=96). The findings were extended into studies of human and mouse atherosclerotic lesions in situ, followed by functional investigations in vitro in human carotid smooth muscle cells (SMCs). RESULTS: Pathway analyses highlighted muscle differentiation, iron homeostasis, calcification, matrix organization, cell survival balance, and BCLAF1 (BCL2 [B-cell lymphoma 2]-associated transcription factor 1) as the most significant signatures. BCLAF1 was downregulated in echolucent plaques, positively correlated to proliferation and negatively to apoptosis. By immunohistochemistry, BCLAF1 was found in normal medial SMCs. It was repressed early during atherogenesis but reappeared in CD68+ cells in advanced plaques and interacted with BCL2 by proximity ligation assay. In cultured SMCs, BCLAF1 was induced by differentiation factors and mitogens and suppressed by macrophage-conditioned medium. BCLAF1 silencing led to downregulation of BCL2 and SMC markers, reduced proliferation, and increased apoptosis. Transdifferentiation of SMCs by oxLDL (oxidized low-denisty lipoprotein) was accompanied by upregulation of BCLAF1, CD36, and CD68, while oxLDL exposure with BCLAF1 silencing preserved MYH (myosin heavy chain) 11 expression and prevented transdifferentiation. BCLAF1 was associated with expression of cell differentiation, contractility, viability, and inflammatory genes, as well as the scavenger receptors CD36 and CD68. BCLAF1 expression in CD68+/BCL2+ cells of SMC origin was verified in plaques from MYH11 lineage-tracing atherosclerotic mice. Moreover, BCLAF1 downregulation associated with vulnerability parameters and cardiovascular risk in patients with carotid atherosclerosis. CONCLUSIONS: Plaque echogenicity correlated with enrichment of distinct molecular pathways and identified BCLAF1, previously not described in atherosclerosis, as the most significant gene. Functionally, BCLAF1 seems necessary for survival and transdifferentiation of SMCs into a macrophage-like phenotype. The role of BCLAF1 in plaque vulnerability should be further evaluated.

Feasibility of renal resistive index measurements performed by an intermediate and novice sonographer in a volunteer population.

BACKGROUND: The Doppler-derived renal resistive index (RRI) is emerging as a promising bedside tool for assessing renal perfusion and risk of developing acute kidney injury in critically ill patients. It is not known what level of ultrasonography competence is needed to obtain reliable RRI values. OBJECTIVE: The aim of this study was to evaluate the feasibility of RRI measurements by an intermediate and novice sonographer in a volunteer population. METHODS: After a focused teaching session, an intermediate (resident), novice (medical student) and expert sonographer performed RRI measurements in 23 volunteers consecutively and blinded to the results of one another. Intraclass correlation coefficients and Bland-Altman plots were used to evaluate interobserver reliability, bias and precision. RESULTS: Both non-experts were able to obtain RRI values in all volunteers. Median RRI in the population measured by the expert was 0.58 (interquartile range 0.52-0.62). The intraclass correlation coefficient was 0.96 (95% confidence interval 0.90-0.98) for the intermediate and expert, and 0.85 (95% confidence interval 0.69-0.94) for the novice and expert. In relation to the measurements of the expert, both non-experts showed negligible bias (mean difference 0.002 [95% confidence interval - 0.005 to 0.009, p = 0.597] between intermediate and expert, mean difference 0.002 [95% confidence interval - 0.011 to 0.015, p = 0.752] between novice and expert) and clinically acceptable precision (95% limits of agreement - 0.031 to 0.035 for the intermediate, 95% limits of agreement - 0.056 to 0.060 for the novice). CONCLUSIONS: RRI measurements by both an intermediate and novice sonographer in a volunteer population were reliable, accurate and precise after a brief course. RRI is easy to learn and feasible within the scope of point-of-care ultrasound.

Novel Multiomics Profiling of Human Carotid Atherosclerotic Plaques and Plasma Reveals Biliverdin Reductase B as a Marker of Intraplaque Hemorrhage.

Clinical tools to identify individuals with unstable atherosclerotic lesions are required to improve prevention of myocardial infarction and ischemic stroke. Here, a systems-based analysis of atherosclerotic plaques and plasma from patients undergoing carotid endarterectomy for stroke prevention was used to identify molecular signatures with a causal relationship to disease. Local plasma collected in the lesion proximity following clamping prior to arteriotomy was profiled together with matched peripheral plasma. This translational workflow identified biliverdin reductase B as a novel marker of intraplaque hemorrhage and unstable carotid atherosclerosis, which should be investigated as a potential predictive biomarker for cardiovascular events in larger cohorts.

Preoperative Renal Resistive Index Predicts Risk of Acute Kidney Injury in Patients Undergoing Cardiac Surgery.

OBJECTIVE: To investigate whether an elevated preoperative renal resistive index (RRI) predicts acute kidney injury (AKI) in patients undergoing cardiac surgery. DESIGN: Prospective cohort study. SETTING: University hospital. PARTICIPANTS: Cohort of 96 adult cardiac surgical patients. INTERVENTIONS: Resistive index was measurement the day before surgery. MEASUREMENTS AND MAIN RESULTS: Renal Doppler was used to measure the resistive index in renal cortical or arcuate arteries the day before surgery. An elevated RRI was defined as≥0.7. AKI was defined as an absolute increase in postoperative compared with preoperative serum creatinine levels by≥26 µmol/L or a relative increase by≥50% or a postoperative urine output<0.5 mL/kg for 6 hours or longer. The relative risk of AKI in patients with an elevated RRI compared with those without an elevated RRI was analyzed using logistic regression. Among patients with an RRI<0.7, 6 (16%) developed AKI compared with 21 (36%) with an RRI≥0.7. The mean increases in postoperative serum creatinine levels were 12 µmol/L in those with an RRI<0.7 and 30 µmol/L in those with an RRI≥0.7. The crude odds ratio for AKI in patients with an RRI≥0.7 was 3.03 (1.09-8.42) compared with those with an RRI<0.7. After multivariable adjustment, the odds ratio was 2.95 (0.97-9.00). CONCLUSIONS: Patients with an elevated preoperative RRI have an increased risk of developing AKI after cardiac surgery. In combination with other markers, the RRI might be a tool for identifying patients with an increased risk of developing AKI.

Magnetic resonance imaging and ultrasonography in diagnosis of pelvic vein thrombosis during pregnancy.

INTRODUCTION: Pelvic deep vein thrombosis (DVT) is difficult to diagnose during pregnancy. In a two-center trial, we evaluated the agreement between ultrasonography and magnetic resonance imaging (MRI) in diagnosing the extent of DVT into the pelvic veins during pregnancy. MATERIALS AND METHODS: Pregnant women with proximal DVT were examined both with ultrasound and MRI as part of a study designed for treatment of DVT during pregnancy. Ultrasound was performed using color flow by specialist in vascular ultrasound with Doppler and compression techniques. The MRI sequences consisted of a 2D Time of Flight angiography with arterial flow suppression and maximum intensity projection reconstructions; a 3D, T1-w-prepared gradient echo sequence with fat saturation for thrombus imaging; a steady-state free precession sequence; and a Turbo-Spin-Echo. No contrast agent was used. Proportion of agreement (kappa) for detection of DVT in individual veins was measured for different ipsilateral veins and inferior vena cava. RESULTS: All 27 patients were imaged with both techniques at an average gestational age of 29 weeks (range 23-39). Three cases (11.5%) of DVT in the pelvic veins were missed on ultrasound but detected by MRI. The upper limit of the DVT was always depicted at a higher (20 cases, 65.4%) or the same level (seven cases, 34.6%) on MRI than on ultrasound. Agreement expressed as kappa was 0.33 (95% CI 0.27-0.40) demonstrating only fair agreement. In one woman the thrombus had propagated into the inferior vena cava, shown only on MRI. CONCLUSION: Our study suggests that in pregnant women there is only fair agreement between ultrasound and MRI for determination of extent of DVT into pelvic veins, with MRI showing consistently more detailed depiction of extension. Our results indicate that MRI has an important role as a complementary technique in the diagnosis of DVT during pregnancy.

Noninvasive real-time imaging of intima thickness after rat carotid artery balloon injury using ultrasound biomicroscopy.

OBJECTIVES: High frequency ultrasound imaging for small animal research (ultrasound biomicroscopy, UBM) has recently become available. Here, we evaluated the possibility to determine intima thickness in the rat carotid artery after balloon injury and to monitor intimal hyperplasia formation by UBM during pharmacological treatment. METHODS: Balloon injury of the left carotid artery was performed on Sprague-Dawley rats. Carotid arteries of all animals were examined by Vevo 770 UBM (VisualSonics Inc.) using 55 MHz probe at day 1, 7, 14 and 21 after the injury. Whole vessel wall, intima and media thicknesses as well as lumen diameter were measured at different levels. Histomorphometric analyses were performed on day 14 and 21. A group of animals were treated with picropodophyllin, an insulin-like growth factor-1 receptor inhibitor. RESULTS: Ex-vivo comparison of UBM and histology demonstrated an excellent correspondence of intimal tears, and the internal and external elastic membranes could be identified. We found also an agreement (Bland-Altman test) between histological measurements and UBM delineations of the rat carotid artery wall layers, with a significant correlation for intima-media thickness (r=0.97; p<0.0001) and intima measurements. We were able to follow changes in the vessel wall structure and vessel diameter as a response to balloon injury in real time. Furthermore, the therapeutic effect of picropodophyllin could be assessed using UBM. CONCLUSIONS: UBM provides a reliable noninvasive, in-vivo visualization of rat vasculature. It allows us to perform longitudinal studies of intimal thickness progression and regression as well as lumen changes in individual animals.

Long-term outcome of infrainguinal percutaneous transluminal angioplasty.

PURPOSE: To evaluate the long-term outcome of infrainguinal percutaneous transluminal angioplasty (PTA). METHODS: Between 1991 and 1994, 77 patients (45 men; mean age 70 years, range 41-85) underwent infrainguinal PTA for occlusive disease. Patient records and angiographic examinations were reviewed to extract data to a patient register. A long-term (mean 9.3 years) follow-up examination of survivors was performed, including physical evaluation, walking impairment questionnaire (WIQ), and duplex ultrasound. RESULTS: Cumulative primary and secondary patency rates, respectively, were 81% and 86% at 1 year, 65% and 73% at 5 years, and 12% and 17% at 10 years. Patency rates were better for patients with claudication than critical ischemia (p=0.02). Stenoses had better primary patency than occlusions (p=0.001), but there was no difference between stenoses <2 cm versus >/=2 cm. At long-term follow-up, patients with patent vessels (50%) had better ankle-brachial indices (p=0.01) and less pain in their calves (p=0.04) compared to patients with non-patent vessels, but there was no difference in walking capacity or quality of life. Generalized femoral artery disease (p=0.03) and diabetes mellitus (p=0.03) predicted poor survival. CONCLUSIONS: Although the overall long-term patency of infrainguinal PTA is poor, the technique has a low morbidity and can be performed in selected patients with a reasonable long-term result.