The growth of xenotransplanted hearts can be reduced with growth hormone receptor knockout pig donors.

OBJECTIVE: Genetically engineered pigs are thought to be an alternative organ source for patients in end-stage heart failure unable to receive a timely allograft. However, cardiac xenografts exhibit growth and diastolic heart failure within 1 month after transplantation. Grafts function for up to 6 months, but only after administration of temsirolimus and afterload-reducing agents to reduce this growth. In this study we investigated the growth and hemodynamics of growth hormone receptor (GHR) knockout xenografts, without the use of adjuncts to prevent intrinsic graft growth after transplantation. METHODS: Genetically engineered pig hearts were transplanted orthotopically into weight-matched baboons between 15 and 30 kg, using continuous perfusion preservation before implantation (n = 5). Xenografts included knockout of carbohydrate antigens and knockin of human transgenes for thromboregulation, complement regulation, and inflammation reduction (grafts with intact growth hormone, n = 2). Three grafts contained the additional knockout of GHR (GHR knockout grafts; n = 3). Transthoracic echocardiograms were obtained twice monthly and comprehensively analyzed by a blinded cardiologist. Hemodynamics were measured longitudinally after transplantation. RESULTS: All xenografts demonstrated life-supporting function after transplantation. There was no difference in intrinsic growth, measured using septal and posterior wall thickness and left ventricular mass, on transthoracic echocardiogram out to 1 month in either GHR knockout or GHR intact grafts. However, hypertrophy of the septal and posterior wall was markedly elevated by 2 months post transplantation. There was minimal hypertrophy out to 6 months in GHR knockout grafts. Physiologic mismatch was present in all grafts after transplantation, which is largely independent of growth. CONCLUSIONS: Xenografts with GHR knockout show reduced post-transplantation xenograft growth using echocardiography >6 months after transplantation, without the need for other adjuncts.

Clinical outcomes and echocardiographic characteristics between African American and Caucasian patients with acute pulmonary embolism.

BACKGROUND: Despite socioeconomic disparities, no association between clinical presentation and poor outcomes explains a higher mortality in African Americans with pulmonary embolism (PE). The objective is to identify the co-morbidities and echocardiographic characteristics associated with increased mortality in African American patients. METHODS: This is a cross-sectional study of Caucasian or African American patients with PE diagnosed between October 2015 and December 2017 at University of Maryland Medical Center. The outcomes were in-hospital death, length of stay, and bleeding. RESULTS: There were 303 African Americans and 343 Caucasians. Caucasians were older (p = 0.007), males (p = 0.01) with history of coronary artery revascularization (CABG (p = 0.001), coronary stents (p = 0.001)), trauma (p = 0.007), and/or recent surgeries (p = 0.0001). African Americans exhibited higher rates of diabetes (p = 0.01), chronic kidney disease (p = 0.0005), and smoking (p = 0.04). Severity of PE was similar between groups and there was no difference in clot burden size. African Americans had more right ventricular strain on Computer Tomography (p = 0.001) and echocardiogram (p = 0.004); also, underfilled left ventricles (p = 0.02) and higher right ventricular systolic pressures (p = 0.001). There was no difference in hospital mortality (7.1% vs. 7.9%, p = 0.71), length of stay (13.1 ± 16.7 vs 12.8 ± 14.9, p = 0.80) and bleeding (9.0% vs.8.3%. p = 0.72). Mortality was higher in African Americans who received advanced therapies (3.8% vs. 18.8%, p = 0.02). The risk of death increased with age (OR 1.04; 95%CI 1.020-1.073) and with advanced therapies (OR 2.43; 95%CI 1.029-5.769). CONCLUSIONS: Differences in co-morbidities, radiologic findings, and echocardiographic characteristics that may contribute to higher mortality in African American patients, specifically those receiving advanced therapies.

Case of mild Schmid-type metaphyseal chondrodysplasia with novel sequence variation involving an unusual mutational site of the COL10A1 gene.

Schmid-type metaphyseal chondrodysplasia (MCDS) is characterized by short stature with short legs, bowing of the long bones, coxa vara, and waddling gait. MCDS is a relatively common form of MCD. Most mutations that cause MCDS occur within the carboxyl-terminal non-collagenous domain (NC1) of the COL10A1 gene. We performed mutational analysis of the COL10A1 genes in 4 unrelated Korean patients with diagnosed MCDS. Mutational analysis of COL10A1 identified c.1904_1915delinsT (p.Gln635LeufsX10) and c.1969dupG (p.Ala657GlyfsX10), 2 novel frameshift mutations, and c.2030T>A (p.Val677Glu) and c.862G>C (p.Gly288Arg) at unusual mutational sites, which could be pathogenic. We present the first report of the molecular characteristics of MCDS in 4 Korean patients. Our findings suggest that a novel sequence variation involving an unusual mutational site of the COL10A1 gene can cause mild MCDS.

Quantification of human plasma-busulfan concentration by liquid chromatography-tandem mass spectrometry.

BACKGROUND: Busulfan, an alkylating agent administered prior to hematopoietic stem cell transplantation, has a narrow therapeutic range and wide variability in metabolism. We developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for rapid and accurate quantification of plasma busulfan. METHODS: Busulfan was separated and detected using an LC system containing a C18 column equipped with MS/MS. The sample was eluted with a mobile phase gradient for a total run time of 10 min. Plasma busulfan concentration was quantified against a 6-point standard curve in a multiple reaction monitoring mode at mass-to-charge (m/z) 264.1 > 151.1. Precision, recovery, matrix effect, linearity, detection capability, carryover, and stability were evaluated. The range of plasma busulfan concentration was obtained by analyzing samples from 9 children receiving busulfan. RESULTS: The coefficients of variation of within-run and within-laboratory precision were all below 5%. Recoveries were all within the range of 100-105%. Linearity was verified from 0 to 5,000 ng/mL. Limit of detection and limit of quantification were 1.56 and 25 ng/mL, respectively. Carryover rate was within allowable limits. Plasma busulfan concentration was stable for 2 weeks at -20℃ and -80℃, but decreased by 25% when the plasma was stored for 24 hr at room temperature, and by <5% in 24 hr at 4℃. The plasma busulfan concentrations were between 347 ng/mL and 5,076 ng/mL. CONCLUSIONS: Our method using LC-MS/MS enables highly accurate, reproducible, and rapid busulfan monitoring with minimal sample preparation. The method may also enable safe and proper dosage.

Atherosclerotic biomarkers and aortic atherosclerosis by cardiovascular magnetic resonance imaging in the Framingham Heart Study.

BACKGROUND: The relations between subclinical atherosclerosis and inflammatory biomarkers have generated intense interest but their significance remains unclear. We sought to determine the association between a panel of biomarkers and subclinical aortic atherosclerosis in a community-based cohort. METHODS AND RESULTS: We evaluated 1547 participants of the Framingham Heart Study Offspring cohort who attended the 7th examination cycle and underwent both cardiovascular magnetic resonance imaging (CMR) and assays for 10 biomarkers associated with atherosclerosis: high-sensitivity C-reactive protein, fibrinogen, intercellular adhesion molecule-1, interleukin-6, interleukin-18, lipoprotein-associated phospholipase-A2 activity and mass, monocyte chemoattractant protein-1, P-selectin, and tumor necrosis factor receptor-2. In logistic regression analysis, we found no significant association between the biomarker panel and the presence of aortic plaque (global P=0.53). Using Tobit regression with aortic plaque as a continuous variable, we noted a modest association between biomarker panel and aortic plaque volume in age- and sex-adjusted analyses (P=0.003). However, this association was attenuated after further adjustment for clinical covariates (P=0.09). CONCLUSIONS: In our community-based cohort, we found no significant association between our multibiomarker panel and aortic plaque. Our results underscore the strengths and limitations of the use of biomarkers for the identification of subclinical atherosclerosis and the importance of traditional risk factors.

Aortic injury is common following pulmonary vein isolation.

BACKGROUND: Esophageal injury has been documented following pulmonary vein isolation (PVI), but damage to other mediastinal structures such as the aorta is seldom reported. Hyperenhancement of the aorta is occasionally seen on cardiac magnetic resonance imaging with late gadolinium enhancement (CMR LGE) in patients undergoing PVI. OBJECTIVE: To determine the frequency of aortic wall LGE following PVI. METHODS: Patients undergoing PVI with pre- and post-CMR LGE at our institution between January 2009 and September 2011 were retrospectively identified. Patients undergoing MiniMaze at our institution between March 2006 and September 2010 with pre- and post-CMR LGE were retrospectively identified and used as a control group. Studies were assessed for hyperenhancement, which is defined as LGE of the aorta or left atrium (LA) at 10 SD above the mean signal intensity of the aortic blood pool. RESULTS: Forty-seven patients undergoing PVI and 14 patients undergoing MiniMaze were included in this analysis. A significant increase in the number of patients with aortic wall LGE was found post-PVI compared with pre-PVI (28 of 47 vs 14 of 47; P = .018). Ninety-six percent (26 of 27) of those with aortic wall enhancement post-PVI also had post-PVI LA enhancement. Eighty-six percent (24 of 28) of patients with aortic wall LGE post-PVI had direct contact of the LA and aorta on the pre-PVI CMR. Patients undergoing MiniMaze did not exhibit a significant increase in LA or aortic enhancement following surgery. CONCLUSIONS: Rates of aortic wall LGE were increased among patients undergoing PVI but not MiniMaze, despite a trend toward larger LA in the latter group. The clinical implications of aortic LGE remain undefined. However, these data suggest that hyperenhancement of the aorta following PVI is common.

Assessing coronary disease in symptomatic women by the Morise score.

BACKGROUND: Early identification of coronary artery disease (CAD) among symptomatic women is critical given their worse outcomes as compared to men. We evaluated the value of the Morise score, a simple clinical risk score, for the assessment for CAD as determined by computed tomography coronary angiography (CTCA) and compared it to the Diamond-Forrester risk assessment. METHODS: One hundred forty women (mean age, 64±11 years) with chest pain syndromes and no known CAD referred for CTCA were analyzed. Patients were risk stratified for likelihood of CAD by Morise and Diamond-Forrester scores. The presence and degree of CAD were determined by CTCA and classified as normal, nonobstructive (<50% stenosis), or obstructive (>50% stenosis). Total coronary calcium was calculated based on Agatston scores. RESULTS: When risk was assessed by Morise vs. Diamond-Forrester, 5% vs. 7% of women were stratified as low, 41% vs. 82% as intermediate, and 54% vs. 11% as high risk for CAD, respectively. CAD was present in 95 (68%) patients; 22 (16%) had obstructive CAD, and 73 (52%) had nonobstructive CAD. Morise scores significantly correlated with calcium scores (p<0.001) as well as the presence and degree of CAD (p<0.0001). Morise scores also demonstrated significantly higher accuracy (66% vs. 48%, p<0.005) and higher sensitivity (56% vs. 16%, p<0.001) but lower specificity (82% vs. 97%, p<0.05) when compared to Diamond-Forrester risk assessment. CONCLUSIONS: The Morise score performed better than Diamond-Forrester for CAD risk assessment, which highlights the importance and power of a simple history and physical examination in determining women at risk for CAD.

Differential regulation of thrombospondin-1 expression and antiangiogenesis of ECV304 cells by trichostatin A and helixor A.

Trichostatin A and helixor A increased thrombospondin-1 expression by ECV304 cells at both mRNA and protein levels by transcriptional activation through the enhancement of tsp-1 promoter activity. The induction of thrombospondin-1 by these agents potently reduced ECV 304 cell migration and capillary-like tube formation on Matrigel; these findings were confirmed by the neutralization of thrombospondin-1 using a specific antibody. In the presence of exogenous vascular endothelial growth factor, however, these agents had a different effect on the vascular endothelial growth factor-induced tube formation; trichostatin A remarkably inhibited tube formation regardless of the presence of exogenous vascular endothelial growth factor, whereas helixor A reduced it to 70-80% of the control level. Interestingly, when the helixor A-generated conditioned media were concentrated three-fold and the endogenous vascular endothelial growth factor was removed, tube formation was remarkably inhibited compared with the effect of three-fold concentrated conditioned media that had endogenous vascular endothelial growth factor. Additionally, in media with endogenous vascular endothelial growth factor that were concentrated five-fold, tube formation was markedly blocked regardless of the presence of exogenous or endogenous vascular endothelial growth factor. Thus, our results indicate that trichostatin A-induced or helixor A-induced antiangiogenesis is mediated by both agents; increased, absolute and relative levels of thrombospondin-1 to the vascular endothelial growth factor level are critical in angiogenesis.

Inhibition of trichostatin A-induced antiangiogenesis by small-interfering RNA for thrombospondin-1.

Expression of thrombospondin-1 (TSP-1), which is a known inhibitor of tumor growth and angiogenesis, is reciprocally regulated by positive regulators, such as VEGF. Additionally, trichostatin A (TSA) suppresses tumor progression by altering VEGF levels and VEGF-mediated signaling. Thus, understanding TSA-regulated TSP-1 expression and the effects of altered TSP-1 levels might provide insights into the mechanism of action of TSA in anti-tumorigenesis, and provide an approach to cancer therapy. Here, we examined the effect of TSA on TSP-1 expression, and the effects of TSA-induced TSP-1 on cell motility and angiogenesis, in HeLa and bovine aortic endothelial cells. TSA remarkably increased TSP-1 expression at the mRNA and protein levels, by controlling the TSP-1 promoter activity. Both TSA and exogenous TSP-1 reduced cell migration and capillary-like tube formation and these activities were confirmed by blocking TSP-1 with its neutralizing antibody and small-interfering RNA. Our results suggest that TSP-1 is a potent mediator of TSA-induced anti- angiogenesis.