Ferenc Manczur

Intracoronary injection of in situ forming alginate hydrogel reverses left ventricular remodeling after myocardial infarction in Swine.

OBJECTIVES This study sought to determine whether alginate biomaterial can be delivered effectively into the infarcted myocardium by intracoronary injection to prevent left ventricular (LV) remodeling early after myocardial infarction (MI). BACKGROUND Although injectable biomaterials can improve infarct healing and repair, the feasibility and effectiveness of intracoronary injection have not been studied. METHODS We prepared a calcium cross-linked alginate solution that undergoes liquid to gel phase transition after deposition in infarcted myocardium. Anterior MI was induced in swine by transient balloon occlusion of left anterior descending coronary artery. At 4 days after MI, either alginate solution (2 or 4 ml) or saline was injected selectively into the infarct-related coronary artery. An additional group (n = 19) was treated with incremental volumes of biomaterial (1, 2, and 4 ml) or 2 ml saline and underwent serial echocardiography studies. RESULTS Examination of hearts harvested after injection showed that the alginate crossed the infarcted leaky vessels and was deposited as hydrogel in the infarcted tissue. At 60 days, control swine experienced an increase in left ventricular (LV) diastolic area by 44%, LV systolic area by 45%, and LV mass by 35%. In contrast, intracoronary injection of alginate (2 and 4 ml) prevented and even reversed LV enlargement (p < 0.01). Post-mortem analysis showed that the biomaterial (2 ml) increased scar thickness by 53% compared with control (2.9 +/- 0.1 mm vs. 1.9 +/- 0.3 mm; p < 0.01) and was replaced by myofibroblasts and collagen. CONCLUSIONS Intracoronary injection of alginate biomaterial is feasible, safe, and effective. Our findings suggest a new percutaneous intervention to improve infarct repair and prevent adverse remodeling after reperfused MI.

Differential effect of ischaemic preconditioning on mobilisation and recruitment of haematopoietic and mesenchymal stem cells in porcine myocardial ischaemia-reperfusion

Effects of ischaemic preconditioning (IP) on the mobilisation and recruitment of haematopoietic (HSCs) and mesenchymal stem (MSC) cells were determined in porcine coronary occlusion/reperfusion. Thirty-three pigs underwent percutaneous occlusion of the left anterior descending coronary artery (LAD) for 90 minutes (min), followed by 120 min reperfusion. IP was performed in 16 of the 33 pigs by two cycles of 5 min balloon occlusion/reperfusion prior to the 90 min occlusion (group IP vs. group C). Peripheral blood and myocardial tissue concentration of bone marrow origin HSCs (characterised by coexpression of CD31+, CD90+, CD45+) and MSCs (characterised by coexpression of CD44+, CD90+, CD45-) were measured by flow cytometry in the early phase of IP. Plasma/serum levels of stem cell mobilisation factors (stromal cell-derived factor-1a [SDF-1a], vascular endothelial growth factor [VEGF], tumour necrosis factor a[TNF-a] and interleukin-8 [IL-8]) were measured. IP led to a significant increase in circulating HSCs as compared with the group C (475 +/- 233 vs. 281 +/- 264 /ml, p=0.032) in the early phase of IP. In contrast, a rapid and prolonged decrease in level of circulating MSCs was observed in group IP as compared with group C (19 +/- 12 vs. 32 +/- 17 /ml, p=0.015). The recruitment of HSCs and MSCs in infarct and border zone was significantly greater in IP group, indicating a faster homing of MSCs as compared with the rate of mobilisation. Rapid increase in VEGF, TNF-a and IL-8 levels was induced by IP, which, however, was not correlated with the levels of circulating SCs. In conclusion, IP resulted in differential mobilisation and recruitment of HSCs and MSCs in the early phase of cardioprotection.

Experimental results of using autologous rectus fascia sheath for venous patch grafts in dogs

Autologous vascular patch grafts developed from the internal rectus sheath were implanted onto the bilateral common iliac vein and jugular vein of 4 experimental beagle dogs. During the development and implanting of the grafts no technical difficulties or perioperative complications were encountered. The follow-up lasted 6 months and 3 months in the case of the common iliac vein grafts and the jugular grafts, respectively. In the postoperative period, the morphological and functional characteristics of the implanted venous sections were examined by Doppler ultrasonography and CT angiography. Normal patency was detected, and none of these check-ups showed obturation or stenosis. The histological survey showed no mesothelial cell layer, but the insides of the grafts showed total restructuring and were covered by a normal endothelial layer. No difference could be detected between samples harvested 3 and 6 months after implanting. The immunohistochemical examinations using anti-claudin-5 and anti-CD31 antibodies confirmed the preliminary results of the histological examinations that the luminal surfaces of the implanted grafts developed a differentiated monolayer endothelium which was free of degenerative and inflammatory signs. The control examinations show the suitability of the internal rectus sheath as a venous wall donor.

Two-dimensional echocardiographic measurements of the left atrium in dogs with cardiac disease.

The aim of the present study was to verify the validity of two-dimensional echocardiographic (2DE) measurement technique in dogs with left atrial enlargement. Thirty-one dogs with clinically and echocardiographically proven cardiac diseases were randomly selected. The left atrial right-to-left diameter (La(r-l)) and the diameter of the left atrium just above the mitral annulus (La(ama)) as well as the ratio of left atrial to aortic diameter ( La/Ao ) were measured by 2DE. The La (r-l) / La(ama) ratio was independent of body weight (R(2) = 0.0006) and age (R(2) = 0.0012), respectively. A significant linear relationship was found between La(ama) and La/Ao (the ratio that expresses the severity of atrial enlargement): La(ama) = 1.2238 La/Ao + 1.1608 (R(2) = 021; P < 0.01). There was also a positive linear relationship between La(r-l) and La/Ao : La(r-l) = 1.6876 La/Ao + 1.2648 (R(2) = 0.27; P < 0.005). In our dogs with cardiac disease, the La(r-l) / La(ama) ratio showed no significant relation to the La/Ao index (R(2) = 0.028). Thus, La(r-l) / La(ama) proved to be independent of the severity of atrial enlargement. Based on the strong relationship stated in the equation between La ama and La r-l [ La(r-l) / La(ama) = 1.31159 (95% confidence interval)], La(ama) can also be used for the assessment of left atrial size even in dogs with cardiac disease.

Comparison of traditional and sensor-based electronic stethoscopes in beagle dogs

The objective of this study was to compare the auscultatory findings using traditional and electronic sensor-based stethoscopes. Thirty-three adult healthy Beagles (20 females, 13 males, mean age: 4.8 years, range 1.4-8 years) were auscultated by four investigators with different experiences (INVEST-1, -2, -3 and -4) independently with both stethoscopes. Final cardiological diagnoses were established by echocardiography. Mitral murmurs were heard with both stethoscopes by all investigators and echocardiography revealed mild mitral valve insufficiency in 7 dogs (21%, 4 females, 3 males). The statistical sensitivity (Se) in recognising cardiac murmurs proved to be 82% using the traditional stethoscope and 75% using the electronic one in the mean of the four examiners, whilst statistical specificity (Sp) was 99% by the traditional and 100% by the electronic stethoscope. The means of the auscultatory sensitivity differences between the two stethoscopes were 0.36 on the left and 0.59 on the right hemithorax, demonstrating an advantage for the electronic stethoscope being more obvious above the right hemithorax (P = 0.0340). The electronic stethoscope proved to be superior to the traditional one in excluding cardiac murmurs and especially in auscultation over the right hemithorax. Mitral valve disease was relatively common in this clinically healthy research Beagle population.

Angiostrongylosis-related restrictive pneumopathy assessed by arterial blood gas analysis in a dog

Pulmonary angiostrongylosis was diagnosed by the Baermann method and larval identification from faecal and bronchoalveolar lavage samples in a five-month- old male mongrel dog with dyspnoea and cough. Arterial blood gas analysis indicated arterial hypoxaemia and restrictive pneumopathy. In addition to the palliative treatment, fenbendazole was administered (50 mg/kg/24 h per os) for 14 days. The respiratory signs subsided within a short time clinically, but serial arterial blood gas analysis demonstrated an ongoing ventilation disorder. Repeated haematology, thoracic radiography, bronchoscopy and blood gas analysis were performed to follow the course of the disease. The most severe eosinophilia was detected after the beginning of the anthelmintic therapy, and the arterial pO2 level was permanently low. Arterial blood gas analysis provided the most adequate information about the course of the pneumopathy and it greatly facilitated the patients medical management.

Occurrence of mitral valve insufficiency in clinically healthy Beagle dogs.

Chronic degenerative valve disease (CDVD) is the most common cardiac disease in dogs, usually resulting in mitral valve insufficiency (MVI). The goal of this study was to investigate the occurrence of MVI in clinically healthy Beagle populations. A total of 79 adult healthy Beagles (41 females and 38 males; age: 5.6 ± 2.7 years, range 1.4 to 11.7 years) were examined. The diagnosis of MVI was based on the detection of a systolic murmur heard above the mitral valve, and was confirmed by colour flow Doppler (CFD) echocardiography. Systolic mitral valve murmurs were detected in 20/79 dogs (25.3%), of them 11 males and 9 females with no statistically significant gender difference (P = 0.6059). The strength of the murmur on the semi-quantitative 0/6 scale yielded intensity grade 1/6 in 10 dogs, grade 2/6 in 4 dogs, and grade 3/6 in 6 dogs. Mild to moderate MVI was detected by CFD in all these 20 dogs with systolic murmurs. Of them, 17 dogs had mild and 3 demonstrated moderate MVI, showing 10-30% and 30-50% regurgitant jets compared to the size of the left atrium, respectively. The age of dogs with MVI was 7.1 ± 2.3 years, which was significantly different from that of dogs without MVI (5.1 ± 2.7 years, P = 0.0029). No significant differences in body weight (P = 0.1724) were found between dogs with MVI (13.8 ± 2.8 kg) and those without MVI (12.8 ± 3.0 kg). Mitral valve disease causing MVI is relatively common in Beagle dogs, just like in other small breed dogs reported in the literature.