Coronary Research Articles

Commissural Malalignment as a Predictor of Coronary Artery Abnormalities in Patients with Transposition of Great Arteries

Abstract Background In patients with transposition of the great arteries (TGA), commissural malalignment (CM) between semilunar valves may be associated with abnormal coronary (CA) pattern. We intend to assess the degree of CM with incidence of unusual CA anatomy. Methods We proposed a ratio to measure the distance of both ends of the anterior facing sinuses of the pulmonary valve from the facing commissure of the aortic valve. We labeled it as D1 and D2 distance. A ratio (C ratio) of the smaller distance (either D1 or D2 whichever is shorter) over the sum of both D1 and D2 was taken (D1 or D2 whichever is shorter/D1+D2). We related this ratio with the incidence of the unusual CA anatomy in D-TGA patients Results We had a total of 158 patients. We defined the point beyond which the C-Ratio becomes significantly associated with abnormal coronary artery pattern, this represents the median effective level (EL50). The EL50 of the C-Ratio was found to be equal to 31% (0.31). The prediction revealed that the CA pattern would most probably be usual when there is a minor commissural malalignment (C-Ratio less than the EL50) and most probably be unusual when there is a major malalignment (C-Ratio is greater than the EL50). The sensitivity was 71% and the specificity 88% (p-value <0.0001). Conclusions The C-Ratio helps to categorize the degree of CM as minor (less than 0.31) or major (more than 0.31). A higher C-Ratio predicts a higher incidence of unusual CA pattern

Diagnosis of multifocal atherosclerosis using the Celermajer test

Aim. To study the effectiveness of determining atherosclerosis and its severity in the brachiocephalic (BCA), coronary (CA) and femoral (FA) arteries based on the endothelial function test proposed by Celermajer DS. Material and methods . The study included 216 patients: 115 men and 101 women aged 24-87 years (mean age, 61,5±10,73 years). All patients underwent coronary angiography to assess the presence and severity of coronary artery atherosclerosis, and duplex ultrasound of BCA and FA atherosclerosis. The functional activity of the endothelium was assessed using the Celermajer test. Results. Depending on the presence and severity of atherosclerosis in each arterial region (BCA, CA and FA), patients were divided into the following groups: group 1 — patients with intact arteries, group 2 — patients with moderate atherosclerosis, group 3 — patients with severe atherosclerosis. Comparative analysis of brachial artery diameters identified by the Celermajer test revealed a significant difference between the groups. Comparison of Celermajer test results in CA groups was as follows: groups 1 and 2 (p=0,34), groups 1 and 3 (p<0,0001), groups 2 and 3 (p<0,0001). The results of comparing the three BCA groups were as follows: groups 1 and 2 (p<0,05), groups 1 and 3 (p<0,001), groups 2 and 3 (p<0,001); for FA — groups 1 and 2 (p=0,008), groups 1 and 3 (p<0,0001), groups 2 and 3 (p<0,0001). Conclusion . The results showed the applicability of Celermajer test for preliminary assessment of presence and severity of atherosclerosis of BCA, CA and FA. Using Celermajer test, severe atherosclerotic lesion can be verified in all studied arterial systems. Moderate atherosclerosis of BCA and FA was also revealed. However, no reliable results were obtained for detecting moderate CA atherosclerosis with Celermajer test.

Commissural Malalignment as a predictor of coronary artery abnormalities in patients with transposition of great arteries

BackgroundIn patients with transposition of the great arteries (TGA), commissural malalignment (CM) between semilunar valves may be associated with abnormal coronary (CA) pattern. We intend to assess the degree of CM with incidence of unusual CA anatomy.MethodsWe proposed a ratio to measure the distance of both ends of the anterior facing sinuses of the pulmonary valve from the facing commissure of the aortic valve. We labeled it as D1 and D2 distance. A ratio (C ratio) of the smaller distance (either D1 or D2 whichever is shorter) over the sum of both D1 and D2 was taken (D1 or D2 whichever is shorter / D1 + D2). We related this ratio with the incidence of the unusual CA anatomy in D-TGA patients.ResultsWe had a total of 158 patients. We defined the point beyond which the C-Ratio becomes significantly associated with abnormal coronary artery pattern, this represents the median effective level (EL50). The EL50 of the C-Ratio was found to be equal to 31% (0.31). The prediction revealed that the CA pattern would most probably be usual when there is a minor commissural malalignment (C-Ratio less than the EL50) and most probably be unusual when there is a major malalignment (C-Ratio is greater than the EL50). The sensitivity was 71% and the specificity 88% (p-value < 0.0001).ConclusionsThe C-Ratio helps to categorize the degree of CM as minor (less than 0.31) or major (more than 0.31). A higher C-Ratio predicts a higher incidence of unusual CA pattern.

Correlation Between Tendon Xanthomas And Atherosclerotic Disease In Coronary And Brachiocephalic Arteries In Patients With Familial Hypercholesterolemia

Background and Aims: Presence of tendon xanthomas (TX) is a pathognomonic sign of familial hypercholesterolemia (FH) and reportedly linked to accelerated development of atherosclerosis. We aimed to investigate association of TX with coronary (CA) and brachiocephalic (BA) atherosclerosis separately and in context of conventional cardiovascular risk factors.

Association between uric acid and coron ary collateral circulation in stable coronary artery disease patients

Objective The aim of this study was to investigate the association between serum uric acid levels and the development of coronary collateral circulation (CCC) in patients with stable coronary artery disease. Background Serum uric acid can cause atherosclerosis. High serum uric acid levels may be associated with poor CCC in patients with stable coronary artery disease. Patients and methods A cross-sectional study was carried out on 100 patients with stable CAD who underwent coronary angiography and documented total occlusion in one or more of the major coronary arteries in Cardiovascular Department Menoufia University Hospital during the period from 1 February 2016 to 30 January 2017. Development of CCC will be graded according to the Cohen–Rentrop method: grades 2–3 will be classified as good CCC (group A) and grades 0–1 as poor CCC (group B). Results A significant relationship between high level of serum uric acid and poor coronary collaterals was observed. Mean value of uric acid in group A was 4.72 ± 1.69 mg/dl and mean value of uric acid in group B was 6.68 ± 2.36 mg/dl (P Conclusion The measurement of uric acid level provides a good predictor of poor CCC in stable coronary artery disease patients.

In-hospital outcomes of transcutaneous coronary intervention and carotid endarterectomy in hybrid and staged regimens

The aim of this study was comparative assessment of in-hospital outcomes after hybrid and staged surgical management of patients presenting with haemodynamically significant lesions of the coronary (CA) and brachiocephalic arteries (BCA) treated by means of either endovascular or surgical techniques. Over the period from 2010 to 2017, we operated on a total of 197 patients with stenotic lesions of the carotid and coronary arteries. The strategy of revascularization included transcutaneous coronary intervention (TCI) and carotid endarterectomy (CEA). Of these, 73 (37%) patients underwent staged revascularization of the brain and myocardium in various sequence (TCI-CEA or CEA-TCI), with a mean interval between the operations amounting to 9.89±7.36 months. Unfavourable outcomes were regarded as the development of such significant cardiovascular events as myocardial infarction (MI), acute impairment of cerebral circulation, death, repeat unplanned revascularization. For hybrid strategy (TCI+CEA) the index period of assessing the outcomes was the single in-hospital period, whereas for the staged strategy it was the time period beginning from the in-hospital period of the primary operation and ending by the in-hospital period of the second stage. The groups were comparable by the absolute majority of the parameters. More than half of the patients were elderly males. One third had a history of MI. The findings of coronary angiography most often revealed lesions of 1-2 CAs. The average parameters of carotid artery stenosis, according to the BCA angiography varied from 74.9 to 82.6%, with bilateral occlusive stenotic lesions being revealed in every third patient. In connection with more frequent involvement of 1-2 CAs the patients underwent implantation of 1-2 stents. In our sample we used a total of 247 stents. Of these, 119 were uncoated and 128 were drug-eluting stents. No between-group significant differences in the development of unfavourable cardiovascular events during the in-hospital postoperative period were revealed. However, despite this, a pronounced negative tendency of the complication rate was noted in the group of staged revascularization. Non-optimal time intervals between the stages of the operations in a third of cases exceeded one year on the patient's own initiative. Nearly a quarter of patients did not come for the second stage of revascularization. An important finding of our study was no increase in the risk of stent thrombosis in hybrid operations compared with the staged approach, despite administration of a loading dose of clopidogrel after CEA, but not before TCI. Another significant result was the fact of greater availability of revascularization of the myocardium and the brain within the framework of the hybrid strategy as compared with the staged one, which may play an important role in prevention of ischaemic unfavourable events in the remote period of follow up.

Differential distribution and functional impact of BK channel beta1 subunits across mesenteric, coronary, and different cerebral arteries of the rat

Large conductance, Ca2+i- and voltage-gated K+ (BK) channels regulate myogenic tone and, thus, arterial diameter. In smooth muscle (SM), BK channels include channel-forming α and auxiliary β1 subunits. BK β1 increases the channel's Ca2+ sensitivity, allowing BK channels to negatively feedback on depolarization-induced Ca2+ entry, oppose SM contraction and favor vasodilation. Thus, endothelial-independent vasodilation can be evoked though targeting of SM BK β1 by endogenous ligands, including lithocholate (LCA). Here, we investigated the expression of BK β1 across arteries of the cerebral and peripheral circulations, and the contribution of such expression to channel function and BK β1-mediated vasodilation. Data demonstrate that endothelium-independent, BK β1-mediated vasodilation by LCA is larger in coronary (CA) and basilar (BA) arteries than in anterior cerebral (ACA), middle cerebral (MCA), posterior cerebral (PCA), and mesenteric (MA) arteries, all arterial segments having a similar diameter. Thus, differential dilation occurs in extracranial arteries which are subjected to similar vascular pressure (CA vs. MA) and in arteries that irrigate different brain regions (BA vs. ACA, MCA, and PCA). SM BK channels from BA and CA displayed increased basal activity and LCA responses, indicating increased BK β1 functional presence. Indeed, in the absence of detectable changes in BK α, BA and CA myocytes showed an increased location of BK β1 in the plasmalemma/subplasmalemma. Moreover, these myocytes distinctly showed increased BK β1 messenger RNA (mRNA) levels. Supporting a major role of enhanced BK β1 transcripts in artery dilation, LCA-induced dilation of MCA transfected with BK β1 complementary DNA (cDNA) was as high as LCA-induced dilation of untransfected BA or CA.

Abstract 151: Optical Coherence Tomography post-processing towards an automated quantification of coronary artery wall alteration subsequent to Kawasaki Disease

Introduction: Statistical mathematical processing of medical imaging promotes operator-independent interpretation. We sought to identify discriminative image features for a histological disambiguation of KD related coronary (CA) lesions. The ultimate goal is to develop a fully automated algorithm for the quantification of the degradation/healing state of the CA wall structure post KD. Methods: We analyzed OCT CA recordings from two KD patients with (KD + AN + ) and two patients with no history of CA aneurysm (KD + AN [[Unable to Display Character: &amp;#8211;]] ), vs a non KD patient (KD [[Unable to Display Character: &amp;#8211;]] ). Results: In KD [[Unable to Display Character: &amp;#8211;]] , regardless of the radial region of interest (ROI) position in the image, the OCT mean signal intensity presents centrifugally two peaks corresponding to the intima and media, constantly separated (17.1± 2.0 pixels) (fig. 1A). In KD + AN [[Unable to Display Character: &amp;#8211;]] the peaks may disappear (Fig. 1-B left medial hyperplasia) and the distance between remaining crests vary between ROIs (22.7±6.9 Pixels). In KD + AN + these peaks disappear (Figure1-C) and the signal intensity changes drastically between ROIs due to wall restructuration. Figure1-C shows a hatched signal that maybe that of a laminar structure. In this case the variation of gradient intensity may be a discriminative feature. Conclusion: Mathematical modeling of CA wall layers is feasible. While the consistency of the distance between media and intima peaks may discriminate KD [[Unable to Display Character: &amp;#8211;]] from KD + and while the gradient intensity may detect restructuration in KD + AN + , ongoing investigation to discriminate CA lesions include signal homogeneity, energy and contrast. Texture analysis with anatomical correlates (e.g., calcium, fibrosis and clots) may allow automated diagnoses.

Abstract P228: Distribution of Multisite Atherosclerosis in Persons with Metabolic Syndrome &amp; Diabetes: The Multi-Ethnic Study of Atherosclerosis

Background: The extent of atherosclerosis across multiple vascular beds in persons with metabolic syndrome (Mets) and diabetes (DM) has not been documented. We hypothesized a greater presence/extent of multisite atherosclerosis in MetS and DM, vs. neither. Methods: We analyzed four vascular beds (coronary (CA), abdominal aorta (AA), carotid, peripheral vascular) in subjects without cardiovascular disease from the Multi-Ethnic Study of Atherosclerosis, who had complete data on these measures. Multisite atherosclerosis was defined as the presence/extent of CA calcium, AA calcium, carotid intimal medial thickness (disease ≥1mm) and borderline/abnormal (&lt;1 or ≥1.3) ankle brachial index. We then created a composite score summing the continuous gender-stratified standardized z-scores for each measure. ANOVA compared least squares means across disease states; logistic regression gave odds of being in the top quartile of the composite score distribution. We adjusted for non-MetS risk factors (age, gender, ethnicity, smoking, LDL-C, lipid medications, family history). Results: Of 1,771 subjects (mean age 64, 50% male, 40% Caucasian, 25% Hispanic, 21% African American, 14% Chinese), 25% had MetS and 13% DM. Persons with DM or Mets had a greater number of sites positive for atherosclerosis ( figure ). Adjusted mean composite scores increased across disease groups (neither disease 0.24, MetS 0.88, DM 1.38, p&lt;0.001 between groups). Adjusted logistic regression showed that the odds of being in the top quartile of the composite score were higher for those with DM OR=4.42 [2.21-8.83] p&lt;0.001 and MetS OR=2.72 [1.63-4.56] p&lt;0.001, vs. neither condition. Conclusions: Those with MetS or DM have an increased prevalence and extent of multisite atherosclerosis. Whether disease in one vascular bed should prompt further evaluation, and how this relates to future CVD events, requires further investigation. Our findings support the concept that atherosclerosis in those with MetS or DM is more likely to be systemic vs. site-specific.

Three Linked Vasculopathic Processes Characterize Kawasaki Disease: A Light and Transmission Electron Microscopic Study

BackgroundKawasaki disease is recognized as the most common cause of acquired heart disease in children in the developed world. Clinical, epidemiologic, and pathologic evidence supports an infectious agent, likely entering through the lung. Pathologic studies proposing an acute coronary arteritis followed by healing fail to account for the complex vasculopathy and clinical course.Methodology/Principal FindingsSpecimens from 32 autopsies, 8 cardiac transplants, and an excised coronary aneurysm were studied by light (n=41) and transmission electron microscopy (n=7). Three characteristic vasculopathic processes were identified in coronary (CA) and non-coronary arteries: acute self-limited necrotizing arteritis (NA), subacute/chronic (SA/C) vasculitis, and luminal myofibroblastic proliferation (LMP). NA is a synchronous neutrophilic process of the endothelium, beginning and ending within the first two weeks of fever onset, and progressively destroying the wall into the adventitia causing saccular aneurysms, which can thrombose or rupture. SA/C vasculitis is an asynchronous process that can commence within the first two weeks onward, starting in the adventitia/perivascular tissue and variably inflaming/damaging the wall during progression to the lumen. Besides fusiform and saccular aneurysms that can thrombose, SA/C vasculitis likely causes the transition of medial and adventitial smooth muscle cells (SMC) into classic myofibroblasts, which combined with their matrix products and inflammation create progressive stenosing luminal lesions (SA/C-LMP). Remote LMP apparently results from circulating factors. Veins, pulmonary arteries, and aorta can develop subclinical SA/C vasculitis and SA/C-LMP, but not NA. The earliest death (day 10) had both CA SA/C vasculitis and SA/C-LMP, and an “eosinophilic-type” myocarditis.Conclusions/SignificanceNA is the only self-limiting process of the three, is responsible for the earliest morbidity/mortality, and is consistent with acute viral infection. SA/C vasculitis can begin as early as NA, but can occur/persist for months to years; LMP causes progressive arterial stenosis and thrombosis and is composed of unique SMC-derived pathologic myofibroblasts.

Results of Coronary Artery Bypass Graft Surgery.

INTRODUCTION: The aim of coronary artery bypass graft surgery is to relieve angina, protect from late myocardial infarction and possibly prolong survivail1 ,2,3,4) In Pakistan, this operation is still. in its evolutionary stage. It has been thought that Asian patients have smaller caliber and more diffusely diseased coronary arteries which may produce less satisfactory results after surgery than in the western patients. The purpose of this paper is to analyze the early and medium term results of myocardial revascularization at AFIC Rawalpindi. PATIENTS AND METHODS: Between December 1981 and May 1985, 106 patients underwent coronary artery bypass graft surgery at AFIC Rawalpindi. There were 104 males and 2 females ranging in age between 33 and 65 years (mean 49 years). The age distribution is shown in Table-I. The majority were between 41 and 60 years of age. DISCUSSION: It is widely accepted that the aims of corona ry artery bypass graft surgery include relief of angina, protection from late myocardial infarction and possibly improved surviva12’3’4 However, preoperative myocardial infarction may Occur in 5 20% of the cases5’6’ late myocardial infarction may occur in• up to 10% of cases, and complete or partial relief of symptoms may be obtained in up to 90% of patients at 5 years.

Comparing a High-Dose Dipyridamole SPECT Imaging Protocol with Dobutamine and Exercise Stress Testing Protocols. Part II: Using High-Dose Dipyridamole to Determine Lung-to-Heart Ratios.

Determination of the severity of coronary artery disease (CAD) by single photon emission computed tomography (SPECT) imaging has previously been shown to have greater sensitivity, specificity, and accuracy when performed with pharmacologic stress using high-dose dipyridamole (HDD), than by standard dose dipyridamole (SDD) or exercise stress (EST) prior to SPECT imaging. The use of lung-to-heart (L:H) ratios has been shown to be valuable in determining the presence or absence of left main (LM) or triple vessel (3V) CAD. Fifty-four patients were studied; HDD (n = 40) or EST (n = 14) was used for the study. These patients underwent L:H ratio analysis, in which anterior views were used 5-10 minutes after the injection of 3 mCi of T1-201. Results of the L:H ratios were compared with the diagnosis of epicardial CAD, as determined by coronary (CA) arteriography. Patients who were "stressed" using either HDD or EST demonstrated statistically greater (p < 0.001) L:H ratios if they had LM/3V CAD when compared with patients who had 0-2 significantly stenosed coronary arteries. Though L:H ratios were greater when HDD pharmacologic stress was used, there was no statistical (p = NS) differences between the two groups. Increased L:H ratios with HDD and EST provide excellent markers for LM/3V CAD using T1-201 imaging. Coupled with previously reported SPECT data, the use of HDD shows promise for increasing the diagnostic accuracy of SPECT imaging.

Age-related changes in isoprostane-mediated relaxation of piglet blood vessels

We studied the putative relaxant effects of several isoprostanes (8-iso-PGE1, and 8-iso-PGE2, 8-iso-PGF1alpha, 8-iso-PGF1beta, 8-iso-PGF2alpha, and 8-iso-PGF2beta) on pulmonary (PA), mesenteric (MA), coronary (CA) arteries and pulmonary veins (PV), from newborn and 2-week-old piglets. Isoprostanes were compared with agonists of the EP (PGE1, PGE2, and misoprostol), DP (PGD2), and IP (iloprost) receptors. Isoprostane-induced relaxation was only observed when TP receptors were occupied (by U46619) or blocked (by SQ 29,548). Under these conditions, 8-iso-PGE2 induced a relaxation of PA (but not PV or MA) that increased with postnatal age. 8-iso-PGE1, 8-iso-PGE2, and 8-iso-PGF2alpha evoked modest relaxations in CA. 8-iso-PGE2-induced relaxation of PA was impaired by endothelium removal and by the presence of blockers of NO synthase (L-NAME), guanylate cyclase (ODQ), or EP receptor (AH6809). PGE1, PGE2, and misoprostol (but not PGD2 or iloprost) induced a relaxation of PA that increased with age. In conclusion, occupancy or blockade of TP receptors unmasked a relaxant effect of 8-iso-PGE2 in piglet PA. This relaxation increased with postnatal age, was endothelium-dependent and involved EP receptors and NO.

Myostatin gene knockout increases vascular function in skeletal and cardiac muscle tissues

Exercise improves vascular health through mechanisms yet to be defined. Exercise enhances both muscle mass and metabolism, in part by decreasing myostatin (MS). Genetic MS deletion increases muscle mass and metabolism but vascular effects of these changes are unknown. This study tested the hypothesis that MS deletion would alter vascular function in the microcirculation. To test this hypothesis, we compared Ms−/− mice on an ICR background with Ms+/+ ICR as controls. Gracilis (SA), coronary (CA), gonadal (GA) and mesenteric (MA) resistance arteries were analyzed in vitro (±Ca2+, i.d. &lt; 150μm). Acetylcholine (ACh) reactivity was used to assess endothelial relaxation. Similarity was seen between Ms−/− and Ms+/+ in mean arterial pressure (90±9 vs. 90±10 mmHg), heart rate (600±136 vs. 545±93 bpm) but in Ms−/− visceral adiposity and plasma leptin (2.4±0.3 vs. 0.6±0.1 ng/ml, p&lt;0.01) were reduced. Maximum passive i.d. was similar in both strains in all arteries. In Ms−/−, dilation to ACh was increased in SA (88±1 vs. 71±4%, p&lt;0.01) and CA (63±2 vs. 51±4%, p&lt;0.01), unchanged in GA and reduced in MA (45±2 vs. 63±4%, p&lt;0.01). Myogenic tone was reduced in CA and SA but unchanged in MA or GA. Taken together, these data indicate that increased muscle mass has pro‐dilatory effects on the microcirculation of muscular organs. These findings may explain, in part, improvements in vascular health seen with exercise training.HL76533

Internal mammary artery smooth muscle cells resist migration and possess high antioxidant capacity

This study investigated whether differences exist in atherogen-induced migratory behaviors and basal antioxidant enzyme capacity of vascular smooth muscle cells (VSMC) from human coronary (CA) and internal mammary (IMA) arteries. Migration experiments were performed using the Dunn chemotaxis chamber. The prooxidant [NAD(P)H oxidase] and antioxidant [NOS, superoxide dismutase, catalase and glutathione peroxidase] enzyme activities were determined by specific assays. Chemotaxis experiments revealed that while both sets of VSMC migrated towards platelet-derived growth factor-BB (1-50 ng/ml) and angiotensin II (1-50 nM), neither oxidized-LDL (ox-LDL, 25-100 microg/ml) nor native LDL (100 microg/ml) affected chemotaxis in IMA VSMC. However, high dose ox-LDL produced significant chemotaxis in CA VSMC that was inhibited by pravastatin (100 nM), mevastatin (10 nM), losartan (10 nM), enalapril (1 microM), and MnTBAP (a free radical scavenger, 50 microM). Microinjection experiments with isoprenoids i.e. geranylgeranylpyrophosphate (GGPP) and farnesylpyrophosphate (FPP) showed distinct involvement of small GTPases in atherogen-induced VSMC migration. Significant increases in antioxidant enzyme activities and nitrite production along with marked decreases in NAD(P)H oxidase activity and O2- levels were determined in IMA versus CA VSMC. Enhanced intrinsic antioxidant capacity may confer on IMA VSMC resistance to migration against atherogenic agents. Drugs that regulate ox-LDL or angiotensin II levels also exert antimigratory effects.

The influence of hemodynamics and wall biomechanics on the thrombogenicity of vein segments perfused in vitro1

This study addresses the hypothesis that exposure to peripheral arterial (ART) or coronary (COR) hemodynamics and wall biomechanics affect platelet deposition on vein segments. Intact human saphenous vein (HSV) and porcine internal jugular vein (PIJV) segments were studied under venous (VEN), ART, and COR environments using in vitro perfusion systems. Wall shear stress (tau) and circumferential wall stress (sigma(theta)) were calculated for PIJV segments. Platelet deposition was measured using a radioactive assay. PIJV ART segments exhibited a 14% increase in inner diameter over time (P < 0.05). tau, acting on PIJV ART specimens, was less at 6 h compared with time 0 (P < 0.05). sigma(theta) was lower in the VEN specimens compared with ART and COR groups (P < 0.01). Platelet deposition decreased by 40% on PIJV ART segments (P < 0.05) but increased 3.2-fold on PIJV COR segments (P < 0.05) versus VEN control segments. Platelet deposition was increased 1.75-fold in COR HSV cases versus VEN segments. These data indicate that short-term exposure to COR conditions lead to enhanced platelet deposition, whereas ART conditions decrease platelet deposition.

GENETICALLY MODIFIED ADENOVIRAL VECTOR CONTAINING A HETEROLOGOUS RGD PEPTIDE IN THE HI LOOP OF THE FIBER KNOB IMPROVES GENE TRANSFER TO VASCULAR ENDOTHELIAL CELLS IN ORGAN CULTURE

800 Vascular endothelial cells (VEC) are central to the development of immune and inflammatory processes especially allograft and xenograft rejection. Thus, the genetic manipulation of VEC for transplantation is an attractive option. Adenoviral vectors (Ad) are commonly used for gene therapy, however, very low transfection efficiency has been achieved in intact vasculature. The aim of the present study was to genetically engineer an Ad containing a heterologous RGD peptide epitope in the HI loop of the fiber knob (AdHIRGDLuc) that binds with high affinity to integrin receptors and potentially enhances the capability of gene transfer to VEC in intact blood vessels. Methods: Sections of human and non-human primate blood vessels were obtained during routine organ procurement and preserved in UW solution. Small pieces of aorta, coronary (CA), carotid, pulmonary (PA) and superior mesenteric (SMA) artery, saphena (Saph), vena cava (VC), porta, pulmonary (PV) and superior mesenteric (SMV) vein were placed in individual 48 well plates containing 199 medium supplemented with 10% heat-inactivated fetal calf serum, and cultured at 37°C, in a humidified 5% CO2/air atmosphere. In this organ culture model, described by Fabre et al, the VEC remains intact, and viable as a non-dividing layer for 3-4 days. A non-modified Ad vector (AdCMVLuc), and AdHIRGDLuc encoding a firefly luciferase reported gene, were used. Gene transfer was made with 1 × 109 particle forming units per well in 300 ml of OptiMEM media per well. Complete media was added to the vessels, and incubated 24 hours at 37°C. To assay the gene transfer efficiency, the organ cultures were washed with PBS and 400 mL of Promega 1X cell culture lysis reagent was added. Samples were the homogenized and incubated on ice 1 hour. Luciferase activity was assayed with the Promega kit. The results are expressed as a mean percentage ± SEM. Results:(Figure)FigureConclusions: Significantly higher gene transfer was achieved in intact blood vessels with AdHIRGDLuc compared with the non-modified Ad vector. The technological breakthroughs in generating recombinant Ad vectors with modified fibers containing novel peptides open a broad range of therapeutic opportunities for transplant atherosclerosis and chronic rejection as well as in vascular diseases.

Comparing a high-dose dipyridamole SPECT imaging protocol with dobutamine and exercise stress testing protocols. Part II: Using high-dose dipyridamole to determine lung-to-heart ratios

Determination of the severity of coronary artery disease (CAD) by single photon emission computed tomography (SPECT) imaging has previously been shown to have greater sensitivity, specificity, and accuracy when performed with pharmacologic stress using high-dose dipyridamole (HDD), than by standard dose dipyridamole (SDD) or exercise stress (EST) prior to SPECT imaging. The use of lung-to-heart (L:H) ratios has been shown to be valuable in determining the presence or absence of left main (LM) or triple vessel (3V) CAD. Fifty-four patients were studied; HDD (n = 40) or EST (n = 14) was used for the study. These patients underwent L:H ratio analysis, in which anterior views were used 5–10 minutes after the injection of 3 mCi of T1-201. Results of the L:H ratios were compared with the diagnosis of epicardial CAD, as determined by coronary (CA) arteriography. Patients who were “stressed” using either HDD or EST demonstrated statistically greater (p < 0.001) L:H ratios if they had LM/3V CAD when compared with patients who had 0–2 significantly stenosed coronary arteries. Though L:H ratios were greater when HDD pharmacologic stress was used, there was no statistical (p = NS) differences between the two groups. Increased L:H ratios with HDD and EST provide excellent markers for LM/3V CAD using T1-201 imaging. Coupled with previously reported SPECT data, the use of HDD shows promise for increasing the diagnostic accuracy of SPECT imaging.

A comparison between the acute effects of nitric oxide synthase inhibition and fluid resuscitation on myocardial function and metabolism in entotoxemic dogs

Purpose :Nitric oxide (NO) synthase inhibitors increase mean arterial pressure (MAP) and systemic vascular resistance (SVR) in animal models of sepsis and in humans with septic shock. However, NO synthese inhibitors may cause coronary vessel constriction leading to myocardial ischemia and increased mortality in endotoxemic animals. This study was designed to test the acute effect of N G-nitro- l-arginine (L-NAME) on left ventricular (LV) function and coronary blood flow in a dog model of endotoxemia. Methods :In open chest, anesthetized dogs endotoxemia was induced intravenously (IV) by Escherichia coli lipopolysaccharide at 2 mg/ kg for 60 minutes. This resulted in hypotension, acidosis, and decreased SVR while cardiac index (CI) was maintained. When MAP was ≤60 mm Hg, animals were resuscitated with either dextran (group I), or L-NAME 30 mg/kg IV bolus (group II). Group III received L-NAME only. A fourth group of dogs was given endotoxin and not resuscitated. Animals were followed up for 30 minutes after intervention. Animals in the fourth group were followed up until the MAP was approximately 30 mm Hg. Heart rate, Cl, MAP, LV end systolic and diastolic pressures, dP/dt at a pressure of 40 mm Hg, left anterior descending artery coronary blood flow, regional LV contraction (sonomicrometer crystals), coro nary pressures, gas tension, and lactates were continuously recorded. A catheter placed in the coronary sinus allowed measurement of coronary sinus pressure, as well as coronary sinus lactate and gas tensions. Stroke volume index, stroke work index, systemic vascular resistance index (SVRI), coronary vascular resistance, percent myocardial shortening, myocardial oxygen consumption (Mvo2) and net myocardial lactate production were calculated. Results :In Group I, fluid administration increased MAP, stroke work index, coronary blood flow, percent myocardial shortening, and MvoZ. In Group II, L-NAME increased MAP to the same extent as fluid administration without evidence of coronary ischemia or myocardial dysfunction. L-NAME did not alter MVo 2 in either endotoxemic or nonendotoxemic animals. In group III, L-NAME alone resulted in a significant increase in MAP and SVRI, but its effects on coronary blood flow and LV function were not significant. We did not observe net lactate production in any of the groups. Coronary blood flow increased out of proportion to Mvo 2 in group I animals. Conclusions :We conclude that although L-NAME at 30 mg/kg causes vasoconstriction, its effects on coronary blood flow and LV function were not significant.

Angiotensin II relaxation of rainbow trout vessels in vitro

The effects of salmonid angiotensin II ([Asn1,Val5]ANG II) were examined in isolated trout arteries [celiacomesenteric (CMA), coronary (COA), 3rd or 4th gill arch epibranchial (EBA), ventral aorta (VA)] and veins [anterior cardinal (ACV) and ductus Cuvier strips (DOC)]. ANG II (10(-10)-10(-6) M) produced modest (< 50% other agonists) transient contractions in otherwise unstimulated COA but was a poor agonist in other vessels. In precontracted vessels, ANG II responses were triphasic; transient contraction (P1), relaxation (P2), and partial recovery (P3) and vessel specific. P1 was similar to uncontracted vessels. With 10(-6) MANG II, %P2 was: EBA, 60.3 +/- 8.3% (n = 22); CMA, 48.8 +/- 8.8% (n = 4); ACV, 38.8 +/- 5.3% (n = 29); VA, 29.4 +/- 4.9% (n = 8); DOC, 25.5 +/- 2.4% (n = 14); COA, 13.2 +/- 6.7% (n = 4). P2 in EBA and ACV was dose dependent [EBA vs. ACV: mean effective concentration (EC50) = 3.6 x 10(-9) +/- 8.1 x 10(-10) M, n = 7 vs. 6.2 x 10(-8) +/- 2.3 x 10(-8) M, n = 8, respectively; P < or = 0.05] and inhibited by indomethacin but unaffected by propranolol, NG-monomethyl-L-arginine, saralasin, PD-123177, or DuP-753. Removal of EBA endothelium also inhibited relaxation. By comparison, ANG II did not relax bullfrog arteries (dorsal aorta, systemic arch, CMA) or femoral veins. These results show that, in large vessels of trout, the predominant effect of ANG II is an endothelium-dependent, prostanoid-mediated relaxation that is unaffected by classical ANG II-receptor antagonists.(ABSTRACT TRUNCATED AT 250 WORDS)