Noncultured cell transplantation in an ovine model of right ventricular preparation

OBJECTIVE: Beyond the first 2 months of life, pulmonary artery banding is warranted before two-stage arterial switch operation. The aim of this study was to explore whether myogenic cell transplantation could contribute to right ventricular function during pulmonary artery constriction in an ovine model. METHODS: Sixteen rams were assigned to one of the following groups: group 1, simple pulmonary artery banding (n = 5); group 2, pulmonary artery banding and cell implantation in the right ventricle (n = 7); and group 3, pulmonary artery banding and placebo injection in the right ventricle (n = 4). Hemodynamic assessment with pressure-volume loops was performed on days 0 and 60. The pulmonary artery banding and the injections were achieved through a left fourth intercostal thoracotomy. Autologous myogenic cell implantation was carried out with a noncultured cell preparation, as previously described by our group. Implanted sites were processed with monoclonal antibodies to a fast skeletal-specific isoform of myosin heavy chain (MY32). RESULTS: Skeletal myosin heavy chain expression was detected at 2 months after noncultured cell implantation in all grafted animals. Right ventricular training resulted in statistically significant increased signs of contractility in all three groups. There was no observed difference, however, between the cell therapy group and the other two groups with respect to signs of cardiac function. CONCLUSION: Successful engraftment of noncultured cells into right ventricular myocardium did not translate into a functional benefit that we could demonstrate in our ovine model. Cellular therapy thus is probably not useful to strengthen a left ventricle being retrained through pulmonary artery banding before arterial switch operation. However, cell transplantation may affect the outcome of right ventricular failure long term after atrial switch operation. Although preliminary, this investigation paves the way for further research into cellular cardiomyoplasty, right ventricular failure, and congenital heart disease.     

Chronic stable heart failure model in ovine species

Establishing a chronic heart failure (HF) model is challenging, particularly in the ovine model. The aim of this study was to establish a reproducible model of HF in an ovine model. Seventeen sheep were operated using the left thoracotomy approach. Chronic HF was induced through ligation of the diagonal and marginal branches only. Perioperative hemodynamic and echocardiographic parameters were compared. A total of (3 ± 1) coronary ligations were used. Thirteen animals survived the procedure and were followed up for (15 ± 5) days. The mean arterial pressure, heart rate (HR), mean pulmonary artery pressure (mPAP), central venous pressure, and cardiac output at baseline and prior to animal sacrifice was (75 ± 14 mmHg) and (68 ± 16 mmHg) P = .261; (72 ± 9 bpm), (100 ± 28 bpm) P = .01; (15 ± 4 mmHg) and (18 ± 5 mmHg) P = .034; (10 ± 6 mmHg) and (8 ± 4 mmHg) P = .326; (3.4 ± 1 L/min) and (3.9 ± 1 L/min) P = .286, respectively. The LVEF at baseline and prior to animal sacrifice was (63 ± 13%) and (43 ± 6%) P = .012. Twelve surviving animals were supported with LVAD in a follow-up procedure. Chronic stable HF in sheep was successively established. Clinical symptoms and drastic increase in the mPAP and HR as well as echo findings were the most sensitive parameters of HF. This reproducible ovine model has proven to be highly promising for research regarding HF.     

Effects of autologous bone marrow stem cell transplantation on beta-adrenoceptor density and electrical activation pattern in a rabbit model of non-ischemic heart failure

Background  

Since only little is known on stem cell therapy in non-ischemic heart failure we wanted to know whether a long-term improvement of cardiac function in non-ischemic heart failure can be achieved by stem cell transplantation.     

Pulmonary function in chronic heart failure. Changes after heart transplantation.

To investigate the impact of chronic heart failure on pulmonary function in heart transplant recipients, pulmonary function was evaluated in 41 consecutive patients (mean age 43 years, range 15-57 years) before and 6 months after successful heart transplantation. The pulmonary function tests included measurements of forced vital capacity [FVC], forced expiratory volume in 1.s [FEV1], FEV1/FVC ratio, total lung capacity [TLC], and diffusion capacity for carbon monoxide [TLCO] and KCO [TLCO per l alveolar volume]. Compared to pretransplant values, spirometry after transplantation revealed modest improvements in FVC (from 77 +/- 16 to 88 +/- 21% of predicted [%pred]; p < 0.001) and FEV1 (from 75 +/- 16 to 85 +/- 22%pred; p < 0.001), whereas the FEV1/FVC ratio was unchanged (81% +/- 11 and 80% +/- 10; p = NS). A slight but statistically significant increase in TLC (from 78 +/- 15 to 86 +/- 18%pred, p < 0.001) was also observed. Prior to transplantation the mean TLCO was 76 +/- 17%pred; 7 of the patients had a TLCO below 60%pred (mean 51% pred). In 33 of the 41 patients a reduction in TLCO was observed after transplantation; for all 41 patients the mean fall in TLCO was 14% of the predicted value (SD 12%pred) (p < 0.0001). Likewise, a significant reduction in KCO was noted (p < 0.0001). Multiple regression analysis revealed that high pretransplant TLCO %pred (p = 0.02) and FVC %pred (p = 0.04) were associated with a less favorable outcome concerning posttransplant TLCO %pred. Although normalization of FEV1, FVC and TLC can be anticipated after correction of severe chronic left ventricular failure by heart transplantation, the pronounced concomitant decline in diffusion capacity observed in this study may be explained by underlying pulmonary disease caused by factors other than long-standing heart failure. Our findings support the notion that pulmonary function abnormalities attributable to chronic heart failure should not preclude consideration for heart transplantation.     

Autologous peripheral stem cell transplantation in patients with congestive heart failure due to ischemic heart disease.

OBJECTIVE: Ischemic heart disease accounts for 50% of all cardiovascular deaths and is the leading cause of congestive heart failure. Medical therapy, cardiac assist devices and surgical procedures including heart transplantation have limited efficiency and availability. Stem cell transplantation represents a new therapeutic opportunity for such patients. METHOD: Six patients with the diagnosis of ischemic cardiomyopathy were included in this study. All of the patients had clinical, radiological and echocardiographic signs of heart failure, and reduced left ventricular ejection fraction (LVEF< or =25%). They underwent coronary angiography and stress tests with dobutamine echocardiography, thallium scintigraphy and positron emission tomography to assess myocardial ischemia and viability. Peripheral stem cells were mobilized and collected by apheresis. They were transplanted into areas of injury with open-heart surgery. To increase blood flow to the engrafted areas, coronary artery by-pass surgery was also performed. RESULTS: The patients were followed at least for 4 months. Echocardiography, thallium scintigraphy and positron emission tomography were repeated after at least 6 weeks following surgery. There was a significant increase in life quality and NYHA class. Some benefit was documented on echocardiography, thallium scintigraphy, and positron emission tomography. CONCLUSION: This approach opens a new window in the treatment of 'no hope' patients with congestive heart failure.     

An ovine model of chronic heart failure: echocardiographic and tissue Doppler imaging characterization

BACKGROUND AND AIM OF THE STUDY: Heart failure in the western world is a major health-care issue. In order to validate novel surgical or pharmacological treatments, reproducible animal models of left ventricular dysfunction are necessary. In the current study, we report our data and experience with a model of toxin-induced heart failure in the sheep. METHODS: Sequential intracoronary injections of doxorubicin (0.75 mg/kg) were carried out every 2 weeks until standard echocardiographic and tissue Doppler imaging detection of myocardial systolic dysfunction. The animals were assessed 1 month later and harvested. Indices of cardiac function from baseline to last day of protocol were recorded and their differences were evaluated by a Wilcoxon rank test for paired data. RESULTS: Ten sheep received 2.5 +/- 0.7 intracoronary injections of a cumulative dose of 88.8 +/- 25 mg/m2 doxorubicin. All available parameters demonstrated signs of severe cardiac dysfunction with statistical significance. All hearts demonstrated severe histological lesions, some of which were consistent with doxorubicin-induced toxicity. CONCLUSIONS: The present study shows that this ovine model is reproducible and stable. It can therefore be relevant to the study of chronic heart failure. It will be incorporated in our future studies concerning novel treatments (such as cell therapy) of nonischemic dilated cardiomyopathy.     

Intraoperative cell transplantation for congestive heart failure: experience in China

Despite significant improvement in the management of congestive heart failure (CHF), it still is a major worldwide public health problem. Currently, cell-based regenerative medicine has been developed as a promising therapeutic option for patients with CHF. Considering the large and growing population, it is estimated that over 5 million patients in China may need such a cell-based therapy to replace or repair the damaged myocardium. Cardiac surgery has emerged as an important player in heart cell therapy in China in recent years. Here, we summarize our achievements in both preclinical and clinical studies of intraoperative cell transplantation, and present our understanding of future research in this attractive field.     

Cell transplantation in non-ischemic dilated cardiomyopathy

OBJECTIVE: With a rising incidence, dilated cardiomyopathy (DCM) is regarded as a major health care concern. Although both medical therapy and novel surgical treatments have been applied to treat DCM, the effects of preventing left ventricular (LV) dilatation are limited, and the mortality rate associated with the disease remains high. Thus novel management strategies for improved treatment of DCM are awaited. METHODS: Researchers have found that, in models of regional ventricular dysfunction, transplanted cells induced a profound biological phenomenon that restored contractile function and prevented ventricular dilatation. We have investigated muscle cell transplantation in hamsters with DCM, and have found that heart cells and smooth muscle cells survived in the host myocardium after transplantation, which suppressed LV dilatation and wall thinning, and preserved heart function. Our current studies are focusing on the clinical applicability of these encouraging early findings by evaluating the optimal cell types, the timing of transplantation, and cryopreservation as cell storage. Concurrently, we are investigating the influence of cell transplantation on myocardial remodeling in order to outline the mechanism of benefit afforded by donor cell engraftment. We believe that the timing of cell transplantation with respect to the progression of the underlying disease is critical in preventing ventricular thinning, dilation and preserving cardiac function. CONCLUSIONS: This novel approach can be a clinically applicable biological therapy for patients with progressive DCM. More studies to uncover the specific molecular and cellular effects of cell transplantation on the host myocardium are necessary for future clinical application.     

Percutaneous autologous venous valve transplantation: short-term feasibility study in an ovine model

BACKGROUND: Limited experience with bioprosthetic venous valve percutaneously inserted into femoral veins in 15 patients has been promising in short-term results only to show disappointing long-term results. Percutaneous autogenous venous valve (PAVV) transplantation was explored in an ovine model as a possible alternative treatment. METHODS: PAVV consisted of a vein segment containing a valve that was attached to a stent template. The stent templates (n = 9) were designed and hand made in our research laboratory. They consist of two stainless steel square stents 13 or 15 mm in diameter to fit the ovine jugular veins (JV), which ranges from 10 to 15 mm in diameter. A valve-containing segment of JV was harvested and attached with sutures and barbs inside the stent template (n = 9). The valve devices were then manually folded and front loaded inside the 4 cm chamber of the 13F delivery sheath and delivered into the contralateral JV by femoral vein approach. Transplanted PAVVs were studied by immediate and 3 months venograms. Animals were euthanized at 3 months, and jugular veins harvested to perform angioscopic evaluations in vitro. RESULTS: PAVV transplantation was successful in all nine animals. Good valve function with no reflux was observed on immediate and 3 months venograms in eight valves. The transplanted maximal JV diameter ranged from 10.2 mm to 15.4 mm (mean 13.1 +/- 1.5 mm). Venoscopic examination revealed intact, flexible, nonthickened valve leaflets in eight specimens. One PAVV exhibited normal function of one leaflet only; the other cusp was accidentally cut during the transplantation procedure. All transplanted autologous valves were free of thrombus and incorporated into the vein wall of the host vessel. CONCLUSION: This study demonstrated that autogenous valve transplants remained patent and competent without long-term anticoagulation for up to 3 months. The percutaneous autogenous venous valve may provide in future minimally invasive treatment for patients with chronic deep venous insufficiency, but long-term studies need to be done to document its continued patency and function.     

Severe right heart failure after heart transplantation. A single-center experience

We reviewed our heart transplantation recipient population, using hard criteria defining severe right heart failure (RHF), and analyzed possible risk factors for outcome after RHF. Between 1983 and 1998 621 cardiac transplantations were performed at our institution. RHF was defined by the necessity to implant an assist device or echocardiographically confirmed right ventricular ballooning with concomitant end organ failure. RHF patients were compared with a matched control group. Thirty-five patients (5.9%) with severe RHF after transplantation fulfilled inclusion criteria. Of these, 32 patients died, while none of the control patients died (P < 0.001). Increased preoperative pulmonary capillary wedge (P = 0.005) and mean pulmonary artery pressure (P = 0.006) were identified as significant risk factors for severe RHF. Severe RHF as defined in our study is irreversible in almost every case without differences among therapeutical concepts. Hence, improvement of postoperative outcome necessitates avoidance or aggressive therapy of possible risk factors.     

Adrenocortical cell transplantation reverses a murine model of adrenal failure

Purpose

Although adrenal insufficiency can be managed with steroid replacement, transplantation of adrenocortical cells may represent a more definitive therapy.

Methods

An adrenal failure model was created by adding stress to mice that underwent staged bilateral adrenalectomy. Murine adrenocortical cells were seeded onto collagen sponges. The grafts were implanted under the renal capsule during the first adrenalectomy. Some mice had an additional graft placed next to the kidney. A contralateral adrenalectomy and a laparotomy were performed 1 week after the first adrenalectomy. Two weeks later, blood was collected for corticosterone measurement; and implants were retrieved for adrenal-specific messenger RNA analysis and histology. Mice that underwent the same procedures but received a graft without cells served as controls.

Results

Control group mortality was 100%. Mice that had only one cell-seeded implant had 42% survival, whereas mice that had 2 cell-seeded implants had 100% survival. Retrieved implants demonstrated viable cells and expression of adrenocortical genes. The plasma corticosterone concentration in animals that survived was similar to that in normal mice.

Conclusion

Cells transplantation restored the adrenocortical function in these mice. Further optimization of this technique could bring a curative therapy to patients with adrenal insufficiency.     

Passive ventricular constraint to improve left ventricular function and mechanics in an ovine model of heart failure secondary to acute myocardial infarction

OBJECTIVE: This study investigated the effects on global cardiac function and myocardial energetics of limiting progressive dilatation after infarction by means of a woven polyester jacket cardiac support device. We hypothesized that placement of the cardiac support device results in a decrease in myocardial wall stress and improvement in cardiac function and myocardial energetics. METHODS: To investigate the effect of passive constraint on left ventricular function and mechanics, a total of 10 sheep were studied with pressure-volume analysis and magnetic resonance imaging. A baseline study was followed by the creation of an anterior infarct. After 1 week, the animals underwent a second study. The cardiac support device was then placed over the epicardium in 5 sheep; the remaining animals served as controls. A terminal study was performed at 2 months after the infarct. RESULTS: The cardiac support device group at the terminal study exhibited a decrease in end-diastolic volume (control 110.3 +/- 19.8 mL vs cardiac support device 67.6 +/- 4.7 mL, P =.006) and an improved ejection fraction (control 15.5% +/- 5.7% vs cardiac support device 29.46% +/- 4.42%, P =.008) relative to the control group. Myocardial energetics were also enhanced in the cardiac support device group, as evidenced by the significant improvements in potential energy (control 2015 +/- 503 mL. mm Hg/beat vs cardiac support device 885 +/- 220 mL. mm Hg/beat, P =.006), efficiency (control 39.4% +/- 13.6% vs cardiac support device 59.8% +/- 8.5%, P =.044), and oxygen consumption (control 0.072 +/- 0.013 mL O(2)/beat vs cardiac support device 0.052 +/- 0.007 mL O(2)/beat, P =.034). CONCLUSION: Passive constraint with the cardiac support device after infarct prevents further remodeling and may stimulate reverse remodeling in heart failure secondary to acute myocardial infarction. These results suggest that in human beings placement of the cardiac support device after a large anterior myocardial infarction may be effective in halting the remodeling process that often leads to end-stage heart failure. If proved effective, placement of a cardiac support device after large heart attacks has the potential to decrease the incidence of heart failure that results after large myocardial infarctions.     

Rejection with heart failure after pediatric cardiac transplantation.

BACKGROUND: Rejection associated with heart failure or death occurs after pediatric cardiac transplantation but has had limited analysis. METHODS: We analyzed the records of 96 consecutive pediatric cardiac transplant recipients who survived to hospital discharge. RESULTS: Eighteen patients (19%) experienced 23 episodes of heart failure or death associated with rejection. Univariate analysis demonstrated black race (p = 0.041), transplantation after 12 months of age (p = 0.032), later time after transplantation (p = 0.037), rejection episode in the first year after transplantation (p = 0.001), and history of two or more rejection episodes (p < 0.001) were significantly associated with rejection seen with heart failure. A multivariate regression analysis identified two or more rejection episodes to be the only independent risk factor for the development of rejection with heart failure (odds ratio 20; 95% confidence limits, 4-104; p < 0.0001). CONCLUSIONS: This study identified pediatric heart transplant recipients with a history of previous rejection episodes to be at a higher risk for symptomatic or fatal rejection. Further studies are needed to determine if intensification of maintenance immunosuppression, long-term rejection surveillance, or both in patients with multiple rejection episodes could reduce morbidity and mortality from rejection.     

Anaemia and congestive heart failure early post-renal transplantation.

BACKGROUND: Anaemia is common following renal transplantation and is associated with the development of congestive heart failure (CHF). However the prevalence of anaemia in the first year following transplantation and the association between anaemia occurring early and the development of CHF have been understudied. METHODS: In this study, 132 incident patients undergoing tacrolimus and mycophenolate mofetil-based renal transplantation were studied for the prevalence of, and risk factors for, anaemia and CHF in the early period post transplantation. RESULTS: Anaemia occurred in 94.5% and 53.1% of patients at 1 week and 12 months, respectively, and was associated with allograft dysfunction, hypoalbuminaemia, higher mycophenolic acid (MPA) levels, bacterial infection and hypoalbuminaemia. The association with hypoalbuminaemia may reflect the presence of chronic inflammation post-transplantation. Of patients displaying haemoglobin <11 g/dl, 41.1% and 29.4% were treated with erythropoiesis stimulating agents (ESAs) at 1 and 12 months respectively. CHF developed in 26 patients beyond 1 month post-transplantation, with echocardiographic left ventricular systolic function preserved in all but one. CHF was associated with anaemia and lower haemoglobin, allograft dysfunction, duration of dialysis and left ventricular hypertrophy on echocardiography prior to transplantation, suggesting the aetiology of CHF may involve the interplay of diastolic cardiac dysfunction, pre-load mismatch and after-load mismatch. CONCLUSIONS: Modification of risk factors may improve anaemia management post transplantation. Reducing the prevalence of anaemia may in turn reduce the incidence of CHF-these observations support the need for clinical trials to determine how anaemia management may impact CHF incidence.     

Cell transplantation to prevent heart failure: a comparison of cell types

BACKGROUND: Autologous cell transplantation may restore viable muscle after a myocardial infarction. We compared the effect of three cell types or an angiotensin-converting enzyme (ACE) inhibitor on preservation of ventricular function after cardiac injury. METHODS: A uniform transmural myocardial scar was created in adult rats by cryoinjury. Three weeks later the rats were randomly assigned to one of four blinded treatments: transplantation with 5 x 10(6) aortic smooth muscle cells (SMC, n = 12), ventricular heart cells (VHC, n = 13), skeletal muscle cells (SKC, n = 13) or culture medium alone (control, n = 11). The ACE inhibitor group (n = 8) received enalapril (1.0 mg/kg per day), also beginning 3 weeks after cryoinjury. Five and 12 weeks after transplantation, left ventricle (LV) function was assessed in a Langendorff apparatus, and histologic and immunohistological evaluation of the LV scars was performed. RESULTS: At 5 weeks, greater scar elastin content and better LV function was noted with cell transplantation or ACE inhibitor therapy compared with control rats (p < 0.05). Twelve weeks after transplantation, cell-transplanted rats still had greater elastin content and better LV function than control rats, although elastin content and LV function had declined in ACE inhibitor-treated animals to levels below those observed in control rats (p < 0.05). CONCLUSIONS: Transplantation of SMC, VHC, and SKC preserved ventricular function equivalent to the effects of an ACE inhibitor. Muscle cell transplantation, but not ACE inhibitor therapy, continues to be effective later after cryoinjury. No differences were detected between the muscle cells.     

Administration of GAS914 in an orthotopic pig-to-baboon heart transplantation model

BACKGROUND: Long-term survival of transgenic cardiac xenografts is currently limited by a form of humoral rejection named acute vascular rejection. Preformed and elicited cytotoxic antibodies against Galalpha(1,3)Gal terminating carbohydrate chains, known as the primary cause of hyperacute rejection, are crucial for this process. We investigated whether GAS914, a soluble, polymeric form of a Galalpha(1,3)Gal trisaccharide would sufficiently minimize xenograft rejection of hDAF-transgenic pig hearts orthotopically transplanted into baboons. METHODS: Orthotopic heart transplantations were performed using hDAF transgenic piglets as donors and four non-splenectomized baboons as recipients. Baseline immunosuppression consisted of tacrolimus, sirolimus, ATG, steroids. In addition two animals received low-dose GAS914, and two animals high-dose GAS914. One of these baboons received high dose GAS914 and cyclophosphamide induction therapy. Serum levels of anti-Galalpha(1,3)Gal IgM and IgG antibodies, and anti-pig antibodies were controlled daily by anti-Galalpha(1,3)Gal enzyme-linked immunosorbant assay and anti-pig hemolytic assays. Histomorphological (hematoxylin and eosin, elastic van Gieson) and immunohistochemical (IgM, IgG) evaluations were performed on tissue specimens. RESULTS: Following low-dose GAS914 therapy survival time was 1 and 9 days, respectively. In baboons treated with high dosages of GAS914 a survival of 30 h and 25 days could be obtained. GAS914 caused an immediate and significant reduction of both anti-Galalpha(1,3)Gal IgM and IgG antibodies. However, sufficient antibody reduction was independent of dosage and form of application of GAS914. A pre-transplant GAS914 treatment was not necessary to effectively reduce antibody levels and prevent hyperacute rejection. In the early postoperative period preformed anti-pig antibodies corresponded predominantly to anti-Galalpha(1,3)Gal antibodies making them susceptible to GAS914. Subsequently, while anti-Galalpha(1,3)Gal antibodies remained low, anti-pig antibodies increased despite of GAS914 application. Corresponding to increased anti-pig antibody titers depositions of IgM and IgG immunoglobulins were detected, which were possibly non-Galalpha(1,3)Gal-specific. CONCLUSIONS: Following orthotopic transplantation of hDAF-transgenic pig hearts into baboons, GAS914 is able to maintain a sufficient reduction of Galalpha(1,3)Gal-specific cytotoxicity to the graft. GAS914 therefore is able to prevent not only hyperacute rejection, but also acute vascular rejection at its beginning, when serum cytotoxicity to the pig heart appears to be predominantly Galalpha(1,3)Gal-specific. A sustained prevention of acute vascular rejection, however, still requires the identification of antibody specificities other than to Galalpha(1,3)Gal.