In JoVE (1)
Other Publications (5)
- The American Journal of Pathology
- Transplant International : Official Journal of the European Society for Organ Transplantation
- European Journal of Heart Failure
- Laboratory Animals
- European Journal of Pharmaceutics and Biopharmaceutics : Official Journal of Arbeitsgemeinschaft Fur Pharmazeutische Verfahrenstechnik E.V
Articles by Michel Weij in JoVE
Shunt Surgery, Right Heart Catheterization, and Vascular Morphometry in a Rat Model for Flow-induced Pulmonary Arterial Hypertension Diederik E. van der Feen1, Michel Weij2, Annemieke Smit-van Oosten2, Lysanne M. Jorna1, Quint A.J. Hagdorn1, Beatrijs Bartelds1, Rolf M.F. Berger1 1Center for Congenital Heart Diseases, Department of Pediatric Cardiology, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, 2Research and Development Facility, University Medical Center Groningen, University of Groningen This protocol describes a surgical procedure to create a model for flow-induced pulmonary arterial hypertension (PAH) in rats and the procedures to analyze the principle hemodynamic and histological end-points in this model.
Other articles by Michel Weij on PubMed
Egr-1 Expression During Neointimal Development in Flow-associated Pulmonary Hypertension The American Journal of Pathology. Nov, 2011 | Pubmed ID: 21924231 In flow-associated pulmonary arterial hypertension (PAH), increased pulmonary blood flow is an essential trigger for neointimal formation. Using microarray analysis, we recently found that the early growth response protein 1 (Egr-1) transcription factor is increased in experimental flow-associated end-stage PAH. Its role in PAH development is unknown. Here, we assessed the spatiotemporal expression of Egr-1 during neointimal development in flow-associated PAH. Flow-associated PAH was produced in rats by combining monocrotaline administration with an aortocaval shunt. Animals were sacrificed 1 day before or 1 day, 1 week, or 4 to 5 weeks after flow addition. Egr-1 expression was spatiotemporally assessed using laser microdissection, quantitative real-time PCR and immunohistochemistry. In addition, Egr-1 expression was assessed in a non-neointimal pulmonary hypertension model and in human PAH associated with congenital shunt. In 4 to 5 weeks, rats subjected to increased flow developed PAH with neointimal lesions. Egr-1 mRNA was increased 1 day after flow addition and in end-stage PAH, whereas monocrotaline only did not result in increased Egr-1 mRNA. Directly after flow addition, Egr-1 was expressed in endothelial cells. During disease development, Egr-1 protein expression increased and migrated throughout the vessel wall. In PAH patients, Egr-1 was expressed in vessels with media hypertrophy and neointimal lesions, including plexiform lesions. Thus, Egr-1 may be an important regulator in the development of pulmonary neointimal lesions induced by increased pulmonary blood flow.
Beneficial Effects of Gaseous Hydrogen Sulfide in Hepatic Ischemia/reperfusion Injury Transplant International : Official Journal of the European Society for Organ Transplantation. Aug, 2012 | Pubmed ID: 22716165 Hydrogen sulfide (H2 S) can induce a reversible hypometabolic state, which could protect against hypoxia. In this study we investigated whether H2 S could protect livers from ischemia/reperfusion injury (IRI). Male C57BL/6 mice were subjected to partial hepatic IRI for 60 min. Animals received 0 (IRI) or 100 ppm H2 S (IRI + H2 S) from 30 min prior to ischemia until 5 min before reperfusion. Core body temperature was maintained at 37° C. Animals were sacrificed after 1, 6 or 24 h. Hepatic ischemia caused extensive hepatic necrosis in the IRI animals which coincided with an increase in ALT and AST serum levels. Animals treated with H2 S showed attenuated serum ALT and AST levels and reduced necrotic lesions after 24 h. IRI animals had increased Bcl-2 mRNA expression and increased active Caspase 3 protein, which were both significantly lower in H2 S treated animals. Increased TNFα and IL-6 mRNA in the IRI livers was significantly attenuated by H2 S treatment, as was hepatic influx of Ly-6G positive granulocytes. Hepatic superoxide production after ischemia was attenuated by H2 S treatment. In hepatic ischemia/reperfusion injury, gaseous H2 S treatment is highly protective, substantially reducing necrosis, apoptosis and inflammation. Gaseous H2 S is therefore a very promising treatment for reducing IRI during hepatic transplantation.
Sildenafil Enhances Systolic Adaptation, but Does Not Prevent Diastolic Dysfunction, in the Pressure-loaded Right Ventricle European Journal of Heart Failure. Sep, 2012 | Pubmed ID: 22730335 Right ventricular (RV) failure due to pressure or volume overload is a major risk factor for early mortality in congenital heart disease and pulmonary hypertension, but currently treatments are lacking. We aimed to demonstrate that the phosphodiesterase 5A inhibitor sildenafil can prevent adverse remodelling and improve function in chronic abnormal RV overload, independent from effects on the pulmonary vasculature.
Simultaneous Subcutaneous Implantation of Two Osmotic Minipumps Connected to a Jugular Vein Catheter in the Rat Laboratory Animals. Oct, 2014 | Pubmed ID: 25002205 Subcutaneous osmotic pump implantation connected to a venous catheter is a well-established method for delivering compounds intravenously for an intermediate duration (approximately two weeks). When prolonged release is desired (approximately four weeks) reduced flow rate is needed with a similar pump volume. With a fixed intra-pump compound concentration, reduced flow rate results in unwanted reduced bioavailability of the compound. Prolonged intravenous delivery would therefore need a pump replacement, resulting in increased discomfort and confounding effects on experimental outcome. To overcome this, we describe a method to double the compound infusion rate for four weeks by implanting two low-flow rate osmotic pumps (2.5 µL/h for 28 days) connected to a jugular vein catheter in a single rat. Rats implanted with a single high-flow rate pump (5 µL/h for 14 days) served as controls. Double pump-implanted rats displayed similar post-operative weight gain and physical activity indicating similar levels of discomfort when compared with single pump-implanted rats. Double pump-implanted rats had an increased risk of pump-related complications (four delivery failures [double pump] versus one delivery failure [single pump]). Our data show that double pump implantation is a feasible alternative to changing pumps or the use of extracorporeal pump systems connected via a long wire to partly restrained animals.
A Novel Aerosol Generator for Homogenous Distribution of Powder over the Lungs After Pulmonary Administration to Small Laboratory Animals European Journal of Pharmaceutics and Biopharmaceutics : Official Journal of Arbeitsgemeinschaft Fur Pharmazeutische Verfahrenstechnik E.V. Nov, 2014 | Pubmed ID: 25460152 To evaluate powder formulations for pulmonary administration in pre-clinic research, the powder should be administered to the lungs of small laboratory animals. To do so properly, a device is needed that generates particles small enough to reach deep into the lungs. In this study a newly developed aerosol generator was tested for pulmonary administration of powder to the lungs of mice and its performance was compared to the only currently available device, the Penn-Century insufflator. Results showed that both devices generated powder particles of approximately the same size distribution, but the fine particle fraction needed for deep lung administration was strongly improved when the aerosol generator was used.Imaging studies in mice showed that powder particles from the aerosol generator deposited into the deep lung, where powder from the Penn-Century insufflator did not reach further than the conducting airways.Furthermore, powder administered by using the aerosol generator was more homogenously distributed over the five individual lungs lobes than powder administrated by using the Penn-Century insufflator.