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Biomedical subjects

Arjang Ruhparwar

Publications and source records attributed to Arjang Ruhparwar.

10 recordsLinked to original sources
PubMed2006

In vivo echocardiographic imaging of transplanted human adult stem cells in the myocardium labeled with clinically applicable CliniMACS nanoparticles.

OBJECTIVES: Intramyocardial transplantation of bone marrow-derived cells is currently under clinical evaluation as a therapy of heart failure. A major limitation of all clinical studies dealing with myocardial cell engraftment is the inability to track the fate of the transplanted cells. We present a clinically applicable technique using transesophageal echocardiography (TEE) of CliniMACS nanoparticle labeled transplanted CD133+ cells in ischemic hearts. METHODS AND RESULTS: CD133+ cells were isolated from human bone marrow by CliniMACS magnetic bead selection. Positive (5 x 10(6) cells) cells were transplanted into porcine ischemic myocardium (n = 6). Control animals (n = 5) received medium injection. TEE was performed to demonstrate the distribution of the cells during and 8 weeks after the procedure. Accumulations of labeled CD133+ cells of adjacent injections in the myocardium were discriminatively identified by TEE. CONCLUSIONS: TEE is an elegant method for real-time documentation of successful transplantation and cell colony localization of magnetically labeled CD133+ cells in the ischemic myocardium. Our method should be of special interest for TEE-guided transcatheter injection of cells.

Animals↗
PubMed2005

Intra-vital fluorescence microscopy for intra-myocardial graft detection following cell transplantation.

INTRODUCTION: The aim of our study was the development of a potentially clinically applicable approach, which allows for intra-myocardial detection of the transplanted cells without the need for collection of tissue samples. Intra-myocardial transplantation of myocytes and bone marrow derived cells is currently under clinical evaluation as a therapy of heart failure. A major limitation of all clinical studies for myocardial restoration through cell transfer is the inability to track the fate of the transplanted cells. METHODS: Fetal canine cardiomyocytes were labelled with the non-toxic fluorescent membrane dye Vybrant CM-DiI and injected into the free wall of the left ventricle of six adult mongrel dogs. For subsequent tracking of the cellular graft, the dogs were re-operated and an intra-vital microscope was mounted above the exposed heart within the thorax. RESULTS: Two months following cell transplantation, the fluorescent graft was visible by intra-vital microscopy using a 10x magnification. Histological studies served as microscopic control and confirmed the presence of DiI-labelled cells at the site of injection. Connexin 43 immunoreactivity was visible at junctional complexes between donor and recipient cells, suggesting morphologic coupling as a result of gap junction formation. CONCLUSIONS: Our results demonstrate that in vivo detection of transplanted cells in the heart is feasible. Further technical adjustments will facilitate thoracoscopic and therefore less invasive application of this method.

Animals↗
PubMed2005

A multifunctional bioreactor for three-dimensional cell (co)-culture.

Investigation of cell abilities to growth, proliferation and (de)-differentiation in a three-dimensional distribution is an important issue in biotechnological research. Here, we report the development of a new bioreactor for three-dimensional cell culture, which allows for co-cultivation of various cell types with different culture conditions in spatial separation. Preliminary results of neonatal rat cardiomyocyte cultivation are shown. Isolated neonatal rat cardiomyocytes were cultured in spatial separated bioreactor compartments in recirculating medium on a biodegradable fibrin matrix for 2 weeks. Glucose, lactate, and lactate dehydrogenase (LDH), pO2, pCO2, and pH levels were monitored in the recirculated medium, daily. Morphological characterization of matrix and cells was assessed by hematoxylin and eosin staining, and MF-20 co-immunostaining with 4',6-diamidino-2-phenylindole (DAPI). Cell viability was determined by LIVE/DEAD staining before cultivation and on day 3, 7, and 14. The optimized seeding density in the matrix was 2.0 x 10(7) cells retaining cellular proportions over the cell culture period. The bioreactor allows the maintenance of physiologic culture conditions with aerobic cell metabolism (low release of lactate, LDH), a high oxygen tension (pO2-183.7 +/- 18.4 mmHg) and physiological pH values (7.4 +/- 0.02) and a constant level of pCO2 (43.1 +/- 2.9) throughout the experimental course. The cell viability was sufficient after 2 weeks with 82 +/- 6.7% living cells. No significant differences were found between spatial separated bioreactor compartments. Our novel multifunctional bioreactor allows for a three-dimensional culture of cells with spatial separation of the co-cultured cell groups. In preliminary experiments, it provided favorable conditions for the three-dimensional cultivation of cardiomyocytes.

Animals↗
PubMed2004

Replacement of the aortic root for acute prosthetic valve endocarditis: prosthetic composite versus aortic allograft root replacement.

OBJECTIVE: Aortic root replacement for prosthetic aortic valve endocarditis with accompanying destruction of the aortic root is a well-established surgical intervention. However, there is still no consensus whether prosthetic material or allogeneic material should be used. Here we report on our experience with prosthetic composite and aortic allograft root replacement in such patients during a 10-year interval. METHODS: From 1991 through 2001, 29 patients with prosthetic aortic valve endocarditis combined with aortic root destruction underwent reoperation at our institution. Sixteen patients received aortic root replacement with a cryopreserved aortic root allograft (group A) and 13 with a prosthetic composite graft (group B). The interval between the initial operation and reoperation was 29 months (range, 5-168 months) in group A and 55 months (range, 7-248 months) in group B. RESULTS: Hospital mortality was 18.5% (n = 5 patients, 3 in group A and 2 in group B). Median follow-up was 21 months (range, 1-48 months) for group A and 34 months (range, 1-152 months) for group B (P >.2). Survival at 1 and 5 years was 81% +/- 10% and 81% +/- 10% in group A and 85% +/- 10% and 85% +/- 10% in group B, respectively. No patient underwent reoperation for recurrent prosthetic aortic valve endocarditis. CONCLUSIONS: Our results indicate that excellent long-term results can be achieved regardless of the material used for aortic root replacement in patients with prosthetic aortic valve endocarditis.

Acute Disease↗
PubMed2003

Anticoagulant therapy in pregnant women with mechanical heart valves.

Managing women with mechanical heart valves during pregnancy poses a particular challenge as there are no available controlled clinical trials to provide guidelines for effective antithrombotic therapy. Oral anticoagulation with coumadin-derivates administration is associated with coumarin embryopathy, and subcutaneous administration of unfractioned heparins (UFH) has been reported to be ineffective in preventing thromboembolic complications. Due to the increased risk of thromboembolic events when UFH is used, low molecular weight heparins (LMWH) were considered to be an alternative. The evidence in the literature regarding the long-term use of LMWH as the only anticoagulant after mechanical heart valve replacement is limited only to a few reports encompassing only 25 patients, with treatment failure in 20%. These data show that anticoagulation with LMWH only is neither safe nor effective in preventing thromboembolic events after mechanical heart valve replacement, in pregnant or non-pregnant women.

Anticoagulants↗
PubMed2002

Anticoagulation for prosthetic heart valves during pregnancy: is low-molecular-weight heparin an alternative?

We report on the treatment failure of low molecular weight heparin (LMWH) for anticoagulation in a pregnant woman that underwent artificial mitral valve replacement 10 years prior to her pregnancy. Until she became pregnant warfarin was administered for anticoagulation, but due to the often mentioned increased risk for warfarin-induced maternal and fetal complications, at gestational week 5 the anticoagulation regimen was switched to subcutaneous application of low molecular weight heparin. At gestational week 24 our patient developed acute life-threatening pulmonary edema and hemodynamic instability due to acute mitral valve thrombosis and underwent emergency valve re-replacement with a biological porcine valve. She recovered uneventfully and gave birth to a healthy child at gestational week 35. In addition to our case presentation we review the sparse evidence in the literature regarding anticoagulation in pregnant women with mechanical heart valves and discuss the rational of different anticoagulation regimens with regards to maternal and fetal outcome. Special consideration is directed towards LMWH administration as an alternative to oral anticoagulation during pregnancy in women with mechanical heart valves.

Adult↗
PubMed2002

Transplanted fetal cardiomyocytes as cardiac pacemaker.

BACKGROUND: While morphologic integration of transplanted fetal cardiomyocytes into the ventricular myocardium is a well-known fact, no studies have yet shown transplanted cells to coherently contribute to contraction and electrical excitation of the host myocardium. The aim of this study was to prove the hypothesis that by transplanting cardiomyocytes with a higher intrinsic rhythmic rate into the myocardium of the left ventricle, these cells could act as an ectopic pacemaker by functional coupling with host cardiomyocytes. METHODS AND RESULTS: Dissociated fetal canine atrial cardiomyocytes including sinus nodal cells were delivered into the free wall of the left ventricle of adult canine X-linked muscular dystrophy dogs (n=2). These dogs fail to express Dystrophin in both cardiac and skeletal muscle. In the control group (n=2) fetal skin fibroblasts were used for grafting. A total of 3-4 weeks after transplantation the dogs underwent catheter ablation of the atrioventricular node (AV-node) and subsequent electrophysiological mapping studies. Transplanted cells were identified by Dystrophin immunoreactivity, indicating survival and morphological integration in the recipient heart. The expression of Connexin 43 between donor and recipient cells suggested formation of gap junctions between injected and host cardiomyocytes. After catheter ablation of the AV-node, a ventricular escape rhythm emerged driving the pace of the heart and originating from the labeled transplantation site. This effect could not be observed in the control group (n=2). CONCLUSIONS: The results constitute the first observation of phenomena indicating electrical and mechanical coupling between allogeneic donor cardiomyocytes and recipient myocardium in-vivo. Further experiments are necessary to evaluate the technique as a potential therapy for atrioventricular block.

Animals↗