Development of endothelium-denuded human umbilical veins as living scaffolds for tissue-engineered small-calibre vascular grafts.

Tissue-engineered small-calibre vessel grafts may help to alleviate the lack of graft material for coronary and peripheral bypass grafting in an increasing number of patients. This study explored the use of endothelium-denuded human umbilical veins (HUVs) as scaffolds for vascular tissue engineering in a perfusion bioreactor. Vessel diameter (1.

Minimized extracorporeal circulation system in coronary artery bypass surgery: a 10-year single-center experience with 2243 patients.

Objective: Coronary artery bypass grafting (CABG) is the gold standard for the surgical therapy of multivessel coronary artery disease. To reduce the side effects, associated with standard extracorporeal circulation (ECC), a concept of minimal extracorporeal circulation (MECC) was devised in our center. We report on our 10-year experience with the MECC for coronary revascularization.

Effects of shear forces and pressure on blood vessel function and metabolism in a perfusion bioreactor.

Bovine saphenous veins (BSV) were incubated in a perfusion bioreactor to study vessel wall metabolism and wall structure under tissue engineering conditions. Group 1 vessels were perfused for 4 or 8 days. The viscosity of the medium was increased to that of blood in group 2.

Recellularization of biological heart valves with human vascular cells: in vitro hemocompatibility assessment.

Coverage of cardiovascular bioprostheses with autologous endothelium is used for the purpose of improving blood compatibility. The aim of our study was to analyze endothelialization potential of glutaraldehyde-fixed heart valves, cellular functions of seeded endothelial cells (EC), and the impact of a two-stage seeding protocol using human vascular fibroblasts (FB) and EC from saphenous veins (HSVEC) on cellular functional properties in vitro. Adherence and morphology of adhered cells were assessed by scanning electronic microscopy and immunohistochemistry.

mTOR inhibitors and calcineurin inhibitors do not affect adhesion molecule expression of human macro- and microvascular endothelial cells.

We examined the effect of cyclosporin A, tacrolimus, sirolimus and everolimus on the cell growth, viability, proliferation, expression of cellular adhesion molecules (CAM) and leukocyte (PBMC) binding of human macrovascular (coronary artery, saphenous vein) and microvascular endothelial cells (EC). Tacrolimus did not affect EC integrity, growth or expression of CAM. Exclusively, EC from the coronary arteries showed a reduced cellular growth (about 30%) under cyclosporin A and tacrolimus treatment.

Advantages of human umbilical vein scaffolds derived from cesarean section vs. vaginal delivery for vascular tissue engineering.

The current study investigated whether the mode of delivery and the mode of sample collection affect the functional properties of umbilical veins as scaffolds for vascular tissue engineering purposes. Human umbilical vein (HUV) from planned cesarean-sections (PCS) showed a 1.7-fold higher maximum contraction with potassium chloride compared to spontaneous vaginal deliveries (VDs, p=0.

Impact of diabetic serum on endothelial cells: an in-vitro-analysis of endothelial dysfunction in diabetes mellitus type 2.

Diabetic endothelial dysfunction was characterized by altered levels of adhesion molecules and cytokines. Aim of our study was to evaluate the effects of diabetic serum on cell-growth and proinflammatory markers in human saphenous vein endothelial cells (HSVEC) from diabetic and non-diabetic patients. Diabetic serum showed (1) complementary proliferative activity for non-diabetic and diabetic HSVEC, (2) unchanged surface expression of adhesion molecules, and (3) elevated levels of sICAM-1 in HSVEC of all donors.

Endothelial cell dysfunction after coronary artery bypass grafting with extracorporeal circulation in patients with type 2 diabetes mellitus.

Objective: Type 2 diabetes mellitus is a well-known risk factor in patients with severe coronary artery disease undergoing coronary artery bypass grafting (CABG). The aim of the study was to analyze the endothelial dysfunction in these patients by evaluating postoperative soluble inflammatory cytokines.

Methods: Patients undergoing CABG without (n=15, group A) and with (n=14, group B) diabetes mellitus were analyzed for their release of E-selectin, interleukin-6 (IL-6), and tumor necrosis factor (TNF) up to 3 days postoperatively.

Hyperglycemia increases the levels of vascular cellular adhesion molecule-1 and monocyte-chemoattractant-protein-1 in the diabetic endothelial cell.

Hyperglycemia is the major cause of diabetic angiopathy. Aim of our study was to evaluate the impact of high glucose on cell growth and function of human "diabetic" endothelial cells (EC). Incubation of non-diabetic EC with glucose moderately inhibited cell growth and increased the expression of ICAM-1 and E-selectin.

Validity of a patient-derived system of tissue-specific human endothelial cells: interleukin-6 as a surrogate marker in the coronary system.

The aim of our study was to evaluate the relevance of tissue- and species-specific endothelial cells (EC) to study EC-dependent mechanisms in inflammatory-mediated tissue injury. We established an isolation protocol for highly purified EC (pEC) preparations of different origin and compared EC-specific inflammatory responses. Fluorescence-activated cell separation was used to obtain pEC cultures from different human arterial (coronary artery, internal thoracic artery) and venous (umbilical vein, saphenous vein) vessels.

Identification and reduction of cryoinjury in endothelial cells: a first step toward establishing a cell bank for vascular tissue engineering.

We analyzed a cryopreservation protocol which improves long-term storage of endothelial cells (EC) for tissue engineering purposes. Human umbilical vein EC were frozen in a high-potassium solution containing 10% dimethyl sulfoxide using 3 different cooling rates. After a storage time in liquid nitrogen of 1, 4, or 12 months, samples were thawed and compared to fresh cells in terms of growth rates, anti-inflammatory, and anticoagulant functions.

Properties of the human umbilical vein as a living scaffold for a tissue-engineered vessel graft.

Umbilical cords are usually discarded after delivery, even though they contain a set of functional vessels. We investigated whether the human umbilical vein (HUV) is suitable as a storable scaffold for the tissue engineering of small-caliber vessel grafts. Isolated HUVs were cryopreserved by freezing or vitrification.

mTOR-inhibitors simultaneously inhibit proliferation and basal IL-6 synthesis of human coronary artery endothelial cells.

Divergent results regarding the immunosuppressive effects of mammalian-target-of-rapamycin-(mTOR)-inhibitors on venous endothelial cells (ECs) have highlighted the importance of an accurate EC-model. The purpose of this study was to determine mTOR-inhibitor effects at a specific site of action -- the human coronary-artery-ECs (HCAECs) -- and to compare these data with results gained from cultures of human saphenous vein ECs (HSVECs). This EC-model could enable us to gain insight into site-specific pharmacodynamics and the immunosuppressive management of transplant vasculopathy.

Development of a disease-specific model to evaluate endothelial dysfunction in patients with diabetes mellitus.

Diabetic patients have an increased cardiovascular risk. We propose to characterize the endothelial dysfunction in a disease-specific in vitro model. Human saphenous vein endothelial cells (HSVEC) were isolated from coronary artery bypass patients without and with non-insulin-dependent diabetes mellitus.

Multicentered European study on safety and effectiveness of the On-X prosthetic heart valve: intermediate follow-up.

Background: This study was performed to determine the safety and effectiveness of the On-X valve, a novel mechanical valve substitute.

Methods: Eleven centers participated in a European, multicentered, longitudinal, nonrandomized study of the On-X valve performance. Isolated aortic or mitral valve replacement with an On-X valve was studied in 301 patients.

Direct evidence of endothelial injury during cardiopulmonary bypass by demonstration of circulating endothelial cells.

Endothelial activation is considered a key process in the development of a whole body inflammatory response secondary to cardiopulmonary bypass (CPB). Increased levels of a multitude of soluble mediators have been described as being released during and after cardiac surgery. Circulating endothelial cells have recently been established as a novel marker of endothelial damage in a variety of vascular disorders.

Endothelial apoptosis and circulating endothelial cells after bypass grafting with and without cardiopulmonary bypass.

Objective: We compared profiles of the numbers of circulating endothelial cells (CEC) and the apoptosis-inducing capacity of serum samples on human endothelial cells (hEC) in on-pump and off-pump coronary artery bypass grafting (CABG) patients.

Methods: Blood samples from 30 patients undergoing CABG (randomly assigned to two groups: 15 patients off-pump and 15 on-pump (cardiopulmonary bypass, CPB)) were collected after induction of anesthesia (preoperatively), at weaning from CPB/end of bypass grafting (0 h), and 1, 6, 12, 24, and 48 h afterwards. CEC were isolated with immunomagnetic anti-CD146-coated Dynabeads, and counted in a Nageotte chamber.

Fatal pulmonary failure attributable to viral pneumonia with human herpes virus 6 (HHV6) in a young immunocompetent woman.

Adult respiratory distress syndrome (ARDS) attributable to viral pneumonia is described mainly in immunodeficient persons. ARDS caused by human herpes virus 6 (HHV6) is extremely rare, and to our knowledge only 1 case has been reported in the literature. We present the case of a young woman who developed fatal pulmonary failure most probably attributable to HHV6 pneumonia.

Cryopreservation of human endothelial cells for vascular tissue engineering.

To investigate the influence of cryopreservation on endothelial cell growth, morphology, and function human umbilical vein endothelial cells (HUVECs) were frozen following a standard protocol. Cell suspensions were exposed to 10% dimethyl sulfoxide in a high-potassium solution, cooled to -80 degrees C at 1 degrees C/min and stored in liquid nitrogen for 7-36 days. Samples were thawed in a 37 degrees C water bath and the cryoprotectant was removed by serial dilution.

Extracorporeal circulation in non-cardiac surgery.

Tradition and experience of cardiopulmonary bypass in the hand of cardiac surgeons Led to several spin-offs of this extracorporeal technique. Acute organ support is realized for situations of failing cardiac output, circulatory arrest respectively, of pulmonary failure and of drowning. Extracorporeal circulation is a promising adjunct to aim in better surgical technique and treatment in neurosurgery, thoracic aortic surgery, complex Lung resection, tumor surgery and procedures where safe organ perfusion must be ascertained.

Superiority of voriconazole over amphotericin B in the treatment of invasive aspergillosis after heart transplantation.

Invasive aspergillosis in immuncompromised patients occurs frequently. Surgical therapy in combination with chemotherapy with amphotericin B and itraconazole is standard therapy. We describe a heart transplant recipient with invasive Aspergillus fumigatus infection in the lung, which was treated successfully with voriconazole after systemically high-dose intravenous therapy with amphotericin B failed.

Four years' experience with a miniaturized extracorporeal circulation system and its influence on clinical outcome.

It has been suggested that the morbidity associated with cardiopulmonary bypass can be attributed in part to the blood-material and blood-air interactions in the extracorporeal circulation (ECC). A recently introduced minimized ECC-system (MECC System) should be able to reduce these negative effects associated with ECC. A retrospective analysis was performed comprising 485 patients who were operated on for elective coronary artery bypass grafting (CABG) using the MECC System with intermittent antegrade warm blood cardioplegia (group 1) from January 2000 to February 2004.

Tricuspid valve repair in a case with congenital absence of left thoracic pericardium.

We present a case of severe tricuspid valve insufficiency because of disruption of the anterior tricuspid leaflet with congenital absence of left thoracic pericardium. Findings suggest that tricuspid valve disruption was a result of distorted right ventricular geometry because of luxation of the heart into left thoracic cavity. Tricuspid valve could be repaired by reinsertion of anterior tricuspid leaflet and De-Vega annuloplasty.

Anterior mitral leaflet mobility is limited by the basal stay chords.

Background: We hypothesize that 2 tendon-like anterior basal stay chords, which remain taut during the entire cardiac cycle, limit the motion of the anterior mitral leaflet.

Methods And Results: Sonomicrometric crystals were implanted in 6 sheep at the insertion of stay chords at anterior mitral leaflet (S1 and S2), papillary muscle tips, fibrous trigones, mitral annulus, and the tip of the anterior leaflet (AL). Distances between crystals were recorded before and after section of stay chords.