Techniques used by the UMCG division of experimental cardiology
Animal models and analysis
A number of animal and cell models are used to study cardiac function within the division of experimental cardiology, including intervention studies to investigate the effects of (new) drugs on cardiac function in disease models, and examining the role of specific genes in the development of cardiac diseases. An overview of the animal models currently in use is presented in Table 1. Cardiac function can be analysed using a number of techniques in our animal models. These include echocardiography (ECHO), electrocardiography (ECG), magnetic resonance imaging (MRI), and pressure/volume loop measurements (invasive). We can also determine specific cardiac parameters ex-vivo in a Langendorff perfusion system. Other parameters that can be examined include general metabolism using metabolic cages and glucose tolerance tests. We have a large number of standardized techniques for further molecular and histochemical analysis of cardiac tissue. These include quantitative real-time PCR (e.g. ANP, BNP), Western blot protein analysis, in particular post-translational modifications (e.g. phospho-Akt), histochemistry to determine cardiomyocyte size, capillary density and fibrosis, and immuno-histochemistry.
Table 1. Cardiac animal models
| Technique | Used to study | Key characteristics | Animals | Reference |
|---|---|---|---|---|
| Permanent coronary artery ligation | Post-myocardial infarction cardiac remodelling | Large scar formation, cardiac remodelling, reduced ejection fraction, transition to heart failure (12 weeks). | Mouse, Rat | (Yin et al, 2011) |
| Temporary coronary artery ligation | Ischemia reperfusion effects | Reperfusion injury, scar formation dependent on ligation time. | Mouse, Rat | (Meems et al, 2012) |
| Transverse aortic constriction (TAC) | Pressure overload (left) | Left ventricle hypertrophy and fibrosis, transition towards heart failure (8 weeks) | Mouse | (Yu et al, 2012) |
| Abdominal aortic constriction | RAAS activation resulting in cardiac remodelling | Hypertrophy and fibrosis, neurohormonal activation (renin). | Mouse | (Kuipers et al, 2010) |
| Neurohormonal minipumps: 1. AngII; 2. Iso/PE | Cardiac remodelling | 1. Hypertrophy and fibrosis, inflammation. 2. Hypertrophy and fibrosis, tachycardiomyopathy | Mouse | |
| Aorto-caval shunt | Volume overload (right+left) | Hypertrophy and dilatation of right and left ventricle, slow transition to heart failure (high output heart failure). | Mouse | (Borgdorff et al, 2012) (Bartelds et al, 2011) |
| Pulmonary artery banding (PAB) | Pressure overload (right) | Hypertrophy (4 weeks) and fibrosis (8 weeks). | Mouse, Rat | (Borgdorff et al, 2012) (Bartelds et al, 2011) |
| Running wheel exercise | Physiological hypertrophy | Cardiac hypertrophy without fibrosis, hypercontractility (physiological hypertrophy) | Mouse, Rat | To be published |
| Monocrotaline + shunt | Pulmonary hypertension | RV hypertrophy with dilatation (decompensation). Neointima lesions in pulmonary vessels. | Rat | (Dickinson et al, 2011) |
| Monocrotaline | Pulmonary hypertension | RV hypertrophy and limited dilatation (compensated), Media hypertrophy in pulmonary vessels. | To be published | |
| Ren2 hypertensive rats | Hypertensive HF model | Severe hypertrophy and fibrosis, resulting in fast forward heart failure. | Rat | (de Boer et al, 2004) (Yu et al, 2012) |
| Streptozotocin (STZ) injection | Diabetes type I model | Diastolic dysfunction and myocardial fibrosis | Mouse | Ongoing |
| High fat diet | Diabetes type II model | Insulin resistance in skeletal and cardiac muscle | Mouse | Ongoing |
| Genetic mouse models | Multiple | Depending on the model | Mouse | (Yu et al, 2012) |
Cell models and analysis
Our in vivo animal studies are complemented by in vitro cell studies. We can isolate and culture cardiomyocytes and cardiac fibroblasts (see Table 2). These cells can be treated with different agents to stimulate cardiomyocyte hypertrophy in vitro or induce collagen synthesis in cardiac fibroblasts. Using adenoviral vector systems, we can over-express or silence specific genes in these cells.
Table 2. Commonly used cell models
| Cell type | Used to study | References |
|---|---|---|
| Primary neonatal rat cardiomyocytes | Hypertrophy | (Lu et al, 2012a, Lu et al, 2012b) |
| Adult rat cardiomyocytes | Ca2+ transients, IF- microscopy | (Lu et al, 2012a, Lu et al, 2012b) |
| Mouse cardiac progenitor cells | Cardiomyocyte differentiation | Ongoing |
| Neonatal rat cardiac fibroblasts | Fibrosis | (Lu et al, 2010) |
| Adult cardiac fibroblasts | Fibrosis | Ongoing |
| HL-1 mouse cell line | Cardiomyocyte model | (Kuipers et al, 2010) |
