Cardiovascular drugs attenuated myocardial resistance against ischaemia-induced and reperfusion-induced injury in a rat model of repetitive occlusion

We investigated the impact of cardioprotective drugs on ST-elevation, arrhythmias and infarct size in a rat model of repetitive coronary artery occlusion

Effects of acetylsalicyl acid and clopidogrel on collateral growth in the hypoperfused rat brain model

Hintergrund: Zerebrovaskuläre Erkrankungen sind weltweit die zweithäufigsten Todesursachen. Acetylsalicylsäure (ASS) und Clopidogrel finden als Mono- oder Kombinationstherapien routinemäßigen Einsatz im Rahmen der Sekundärprävention. In dieser Studie wurden die Auswirkungen der anti-inflammatorischen Wirkungen von ASS gegenüber Clopidogrel auf die zerebrale Arteriogenese untersucht. Methoden: Im ersten Teil der Studie, der Untersuchung der Effekte auf das natürliche Kollateralwachstum, wurde bei Sprague Dawley-Ratten die 3-VO- Methode durchgeführt, bei der beide Vertebralarterien und die linke Arteria carotis communis verschlossen werden. Die Tiere wurden dann für 7 oder 21 Tage entweder mit Trinkwasser als Kontrolllösung, ASS oder Clopidogrel behandelt. Im zweiten Teil wurde das Kollateralwachstum durch Gabe des Granulocyte Colony-Stimulating Factors (G-CSF) über eine Woche therapeutisch induziert. Gleichzeitig erfolgte die Behandlung mit Trinkwasser, ASS und Clopidogrel. Nach ein oder drei Wochen wurden jeweils entweder eine zerebrovaskuläre Reaktion oder eine postmortem Latexangiographie zur Bestimmung der Gefäßdurchmesser durchgeführt. Ergebnisse: Während die PCA-Diameter sowohl nach einer als auch nach drei Wochen nach 3-VO unter ASS- oder Clopidogrel- Behandlung keinen Unterschied gegenüber der Kontrollgruppe zeigten, war die hämodynamische Reserve unter ASS zu beiden Zeitpunkten aufgehoben. Der kombinierte Einsatz von ASS und G-CSF verbesserte die Reserve zwar, dennoch blieb sie signifikant schlechter gegenüber der Kombination aus Clopidogrel und G-CSF sowie der Monotherapie mit G-CSF. Die Diameter zeigten nach der Kombination aus ASS und G-CSF keinen Unterschied gegenüber der ASS- Monotherapie und blieben damit bedeutend kleiner gegenüber der G-CSF- Monotherapie. Schlussfolgerung: Die vorliegende Studie konnte zeigen, dass ASS das zerebrale Kollateralwachstum und die hämodynamische Reserve nach therapeutischer Induktion durch G-CSF hemmte, während Clopidogrel dies nicht beeinflusste. Diese Daten haben eine herausragende klinische Bedeutung für deren Einsatz in der Sekundärprävention zerebrovaskulärer Erkrankungen.Background and Purpose: Ischemic heart diseases and cerebrovascular diseases are the leading causes of death worldwide (WHO). Acetylsalicyl acid (ASA) and clopidogrel are well-used in the secondary prevention in their combination or alone. Because of their anti-inflammatory effects ASA inhibits peripheral arteriogenesis, whereas clopidogrel had neutral effects. In this study we investigated the effects of ASA and clopidogrel on adaptive and therapeutically induced cerebral arteriogenesis. Methods: For the first part of the study, the evaluation of the effects on adaptive cerebral arteriogenesis, male Sprague Dawley rats underwent 3-VO surgery, the occlusion of both vertebral arteries and the left common carotid artery, and were treated with either drinking water, ASA or clopidogrel for 7 or 21 days. For evaluation of the effects on therapeutically induced arteriogenesis rats received Granulocyte colony-stimulating factor (G-CSF) every other day for one week in addition to drinking water, ASA or clopidogrel. After one or three weeks rats underwent cerebrovascular reactivity or post-mortem latexangiography. Results: One as well as three weeks after 3-VO PCA diameters were significantly increased compared to untreated rats, but no differences were found in ASA or clopidogrel treated animals compared to 3-VO controls. Hemodynamic reserve capacity was completely abolished at one and three weeks after 3-VO by ASA. The reserve capacity was improved after treatment combined with ASA and G-CSF, but was still significantly decreased compared to the combination of clopidogrel and G-CSF and the single treatment with G-CSF. The diameters were not different after combined treatment with ASA and G-CSF compared to ASA alone and still smaller compared to the G-CSF single treatment. Conclusions: In this study it was shown, that ASA, but not Clopidogrel inhibited collateral growth and hemodynamic reserve capacity after therapeutically induction with G-CSF. These results of the pro-arteriogenic G-CSF as well as the anti-arteriogenic ASA are eminent for their clinical application in the secondary prevention of cerebrovascular events

The Interactive Stress Assessment in Basic Animal Science Training

In order to assess the extent to which the legally prescribed training for the acquisition of animal experimentation expertise provides scientific personnel with the necessary competence and expertise to carry out a correct harm-benefit analysis in the context of animal experimentation applications, we conducted an interactive stress assessment concerning the basic animal experimentation expertise course. First, before the practical part of the course and then, after the practical part, the participants assessed images and video material of healthy and stressed animals. The results were assessed comparatively and showed a significant increase in performance in all categories (p-value < 0.001). In addition, the results were comparatively assessed against those of scientists already experienced in animal experiments and experienced animal caretakers in research and clinics. In all groups, the vast majority of participants were able to recognise stress in laboratory animals. A significant proportion of the participants were also able to rate the level of stress correctly according to three degrees of severity: mild, moderate and severe. Nevertheless, a small number of participants were unable to distinguish between healthy and stressed animals and thus, the stress in the individual groups was assigned very differently from the different degrees of severity. The results of this study illustrate, on the one hand, the high significance that training must have in order to acquire the expertise, and, on the other hand, how strongly the assessment of stress is influenced by subjectivity

Nitroglycerin application and coronary arteriogenesis.

BACKGROUND:In the presence of a coronary occlusion, pre-existing small collateral vessels (arterioles) develop into much larger arteries (biological bypasses) that have the potential to allow a certain level of perfusion distal to the blockage. Termed arteriogenesis, this phenomenon proceeds via a complex combination of events, with nitric oxide (NO) playing an essential role. The aim of this study was to investigate the effects of supplemental administration of NO donors, i.e., short-acting nitroglycerin (NTG) or slow-release pelleted isosorbide dinitrate (ISDN), on collateral development in a repetitive coronary artery occlusion model in rats. METHODS:Coronary collateral growth was induced via a repetitive occlusion protocol (ROP) of the left anterior descending coronary artery (LAD) in rats. The primary endpoints were the histological evaluation of rat heart infarct size and ST-segment elevation (ECG-analysis) upon final permanent occlusion of the LAD (experimentally induced myocardial infarction). The effects of NTG or ISDN were also evaluated by administration during 5 days of ROP. We additionally investigated whether concomitant application of NTG can compensate for the anti-arteriogenic effect of acetylsalicylic acid (ASA). RESULTS:After 5 days of ROP, the mean infarct size and degree of ST-elevation were only slightly lower than those of the SHAM group; however, after 10 days of the protocol, the ROP group displayed significantly less severe infarct damage, indicating enhanced arteriogenesis. Intermittent NTG application greatly decreased the ST-elevation and infarct size. The ISDN also had a positive effect on arteriogenesis, but not to the same extent as the NTG. Administration of ASA increased the infarct severity; however, concomitant dosing with NTG somewhat attenuated this effect. CONCLUSION:Intermittent treatment with the short-acting NTG decreased the size of an experimentally induced myocardial infarct by promoting coronary collateral development. These new insights are of great relevance for future clinical strategies for the treatment of occlusive vascular diseases

Knockout of Density-Enhanced Phosphatase-1 Impairs Cerebrovascular Reserve Capacity in an Arteriogenesis Model in Mice

Collateral growth, arteriogenesis, represents a proliferative mechanism involving endothelial cells, smooth muscle cells, and monocytes/macrophages. Here we investigated the role of Density-Enhanced Phosphatase-1 (DEP-1) in arteriogenesis in vivo, a protein-tyrosine-phosphatase that has controversially been discussed with regard to vascular cell biology. Wild-type C57BL/6 mice subjected to permanent left common carotid artery occlusion (CCAO) developed a significant diameter increase in distinct arteries of the circle of Willis, especially in the anterior cerebral artery. Analyzing the impact of loss of DEP-1 function, induction of collateralization was quantified after CCAO and hindlimb femoral artery ligation comparing wild-type and DEP-1−/− mice. Both cerebral collateralization assessed by latex perfusion and peripheral vessel growth in the femoral artery determined by microsphere perfusion and micro-CT analysis were not altered in DEP-1−/− compared to wild-type mice. Cerebrovascular reserve capacity, however, was significantly impaired in DEP-1−/− mice. Cerebrovascular transcriptional analysis of proarteriogenic growth factors and receptors showed specifically reduced transcripts of PDGF-B. SiRNA knockdown of DEP-1 in endothelial cells in vitro also resulted in significant PDGF-B downregulation, providing further evidence for DEP-1 in PDGF-B gene regulation. In summary, our data support the notion of DEP-1 as positive functional regulator in vascular cerebral arteriogenesis, involving differential PDGF-B gene expression