[Novel uses of afterbirth tissues in regenerative medicine]. / Neue Verwendungsmöglichkeiten von Nachgeburtsgewebe für die Regenerative Medizin.

INTRODUCTION: Afterbirth tissues, which include the umbilical cord, placenta, amnion, and cord blood, are usually discarded. Recent progress in regenerative medicine suggests that we re-evaluate these tissues and assess their therapeutic potential. METHODS: Firstly the unique properties of afterbirth tissues and their current use in regenerative medicine are summarised. Then we introduce the cooperation of our institutions and our experiences regarding the collection and utilisation of afterbirth tissues. RESULTS: A literature survey suggests that besides the well-known transplantation of hematopoietic stem cells from cord blood, afterbirth tissues were also used as a source of stem cells, progenitor cells, differentiated cells, and blood vessels for tissue engineering purposes. According to our own experience, the two participating OB/GYN departments and the blood donation service were able to organise a sufficient supply of umbilical cords for research purposes. The yield correlated with incentives for the midwives. A total of more than 4,300 cords was collected for experiments designed to create small caliber vessel grafts. The contamination rate was low. Birth mode significantly affected umbilical vein function, whereas ischaemia for up to 40 h did not have any deleterious effects. Umbilical veins were cryopreserved with a moderate loss of function. Fresh umbilical veins were endothelium-denuded and reseeded with endothelial cells harvested from coronary artery disease patients to generate an autologous surface. CONCLUSIONS: Afterbirth tissues have unique properties which make them ideally suited for regenerative medicine. These tissues can be procured and utilised in research facilities even in the absence of an in-house birthing centre.

A prospective cross-over study comparing the pharmacokinetics of cyclosporine A and its metabolites after oral versus short-time intravenous cyclosporine A administration in pre-heart transplant patients.

Sometimes intravenous administration of cyclosporine (CsA) is essential before oral administration is possible. There are only a few reports available on the interindividual variability of CsA metabolism and different metabolite pattern depending on intravenous versus oral administration of CsA in heart transplant (HTx) patients. For effective inhibition of calcineurin we used a short infusion reaching peak concentrations after 2 hours. In a prospective cross-over study we compared the pharmacokinetics of CsA and its metabolites after oral (2.0 mg/kg body weight) versus intravenous (0.7 mg/kg body weight; 2-hour infusion) CsA administration (single test dose) in 7 pre-HTx patients. The pharmacokinetic parameters of CsA and its metabolites were analyzed using high-pressure liquid chromatography. The pharmacokinetic parameter area under the concentration time curve (AUC(0-infinity)) of CsA after intravenous administration was significantly lower (2903 ng*h*mL(-1)) than that after oral administration (4344 ng*h*mL(-1); P=.01). Peak concentrations, time to peak concentration, and terminal elimination half life were not significantly different. Short-time infusion of CsA resulted in a significant decrease in the AUC of the metabolites AM1 (3-fold), AM9 (10-fold), and AM1c (3-fold). A 2-hour infusion of CsA is just as effective as oral administration and the reduced amount of metabolites is advantageous for the patient.

Recombinant human antithrombin III restores heparin responsiveness and decreases activation of coagulation in heparin-resistant patients during cardiopulmonary bypass.

OBJECTIVES: We sought to evaluate the efficacy of recombinant human antithrombin III for restoration of heparin responsiveness in heparin-resistant patients scheduled for cardiac surgery. METHODS: This was a multicenter, randomized, double-blind, placebo-controlled study in heparin-resistant patients undergoing elective cardiac surgery. Patients were considered heparin resistant if the activated clotting time was less than 480 seconds after 400 U/kg heparin. Fifty-two heparin-resistant patients were randomized into 2 cohorts. One cohort received a single bolus (75 U/kg) of recombinant human antithrombin III (n = 28), and the other, the placebo group (n = 24), received a normal saline bolus. If the activated clotting time remained less than 480 seconds, this was defined as treatment failure, and 2 units of fresh frozen plasma were transfused. Patients were monitored for adverse events during hospitalization. RESULTS: Six (21%) of the patients in the recombinant human antithrombin III group received fresh frozen plasma transfusions compared with 22 (92%) of the placebo-treated patients ( P < .001). Two units of fresh frozen plasma did not restore heparin responsiveness. There was no increased incidence of adverse events associated with recombinant human antithrombin III administration. Postoperative 24-hour chest tube bleeding was not different in the 2 groups. Surrogate measures of hemostatic activation suggested that there was less activation of the hemostatic system during cardiopulmonary bypass in the recombinant human antithrombin III group. CONCLUSION: Treatment with recombinant human antithrombin III in a dose of 75 U/kg is effective in restoring heparin responsiveness and promoting therapeutic anticoagulation for cardiopulmonary bypass in the majority of heparin-resistant patients. Two units of fresh frozen plasma were insufficient to restore heparin responsiveness. There was no apparent increase in bleeding associated with recombinant human antithrombin III.

Mitral prolapse caused by lymphangioma.

A 62-year-old female patient with known mitral-valve prolapse for the previous five years presented with progressive dyspnea and intermittent palpitations. This clinical presentation was investigated by two-dimensional echocardiography which revealed moderate mitral regurgitation due to a pedunculated mass oscillating between the left atrium and the left ventricle. Successful operative treatment consisted of en-bloc resection of the tumor from the anterior mitral valve leaflet and its primary cords and subsequent reconstruction of the mitral valve. Pathohistological examination revealed a cystic lymphangioma originating from mitral-valve tissue. To our knowledge this is the first reported case in the literature.

Predominant inhibition of interleukin-6 synthesis in patient-specific endothelial cells by mTOR inhibitors below a concentration range where cell proliferation is affected and mitotic arrest takes place.

UNLABELLED: Organ rejection and inflammation are accompanied by endothelial cell activation. An in vitro model with patient-specific endothelial cells was used to study the impact of mTOR inhibitors on cell growth and release of proinflammatory cytokines. MATERIAL AND METHODS: Confluent monolayers of human saphenous vein endothelial cells were pretreated with everolimus or sirolimus followed by induction with tumour necrosis factor-alpha (TNF-alpha). RESULTS: Incubation with sirolimus or everolimus resulted in a dose-dependent deceleration of cell growth. Compared to control, cell count at high concentrations ceased to increase and remained at 60%. This mitotic arrest was accompanied by a dose-dependent inhibition of the TNF-alpha-induced in situ synthesis and release of interleukin-6 per cell by 60%. CONCLUSIONS: Under conditions mimicking cytokine-induced cell activation a predominant inhibitory effect of everolimus compared to sirolimus on endothelial cell proliferation was observed paralleled by an inhibition of proinflammatory cytokines. This might attenuate the acute proinflammatory status after transplantation.

Cytological evaluation of the tissue-implant reaction associated with subcutaneous implantation of polymers coated with titaniumcarboxonitride in vivo.

The aim of the present study was to evaluate the influence of titanium-coated polymers on the inflammatory response and remodeling of connective tissue during wound-healing processes. Discs of polyethyleneterephthalate (PET) and silicone as well as high-weight meshes of polypropylene (PP) were coated with a titaniumcarboxonitride (Ti(C,N,O)) layer by a plasma-assisted chemical vapor deposition process (PACVD) and implanted subcutaneously in the dorsal lumbar region of Wistar rats. Light microscopic and histological evaluation of capsule thickness, capsule quality, implant-tissue interface and collagen composition was performed 7, 14, 21 and 28 days post-operatively. All implants were surrounded by a fibrous capsule with decreasing thickness after 2-4 weeks post-implantation. Titaniumcarboxonitride-coated polymers showed no significant differences in capsule thickness and inflammatory cellular response. An increased collagen type III/I ratio, especially for titaniumcarboxonitride-coated materials, was found in week one after implantation remaining elevated up to week 4. This might be associated with disordered collagen metabolism and immature scar reaction. In contrast to previous in vitro experiments, Ti-coating of polymers did not improve biocompatibility after subcutaneous implantation in rats. Material reduction to low-weight meshes and enlargement of pore size may demonstrate a benefit of Ti-coated meshes with an increased biocompatibility.

The aortomitral angle is suspended by the anterior mitral basal "stay" chords.

OBJECTIVES: The function of the anterior mitral basal "stay" chords (SC) is not yet known. Collagen fiber orientation of the anterior mitral leaflet (AML) suggests that local stress is directed from papillary muscles (PM) over SC and AML to fibrous trigones (FT), maintaining the aortomitral angle (AMA). It has been shown that narrowing of AMA increases risk of systolic anterior movement (SAM). METHODS: Sonomicrometry crystals were implanted in six sheep at the left ventricular (LV) apex, PM tips (M1, M2), FT (T1, T2), posterior mitral annulus (PMA), and base of aortic right coronary sinus (RCS). The retracting force of ascending aorta was measured. RESULTS: Transection of SC resulted in an increase of distance M1-T1 and M2-T2. Consequently, the AMA narrowed at end systole by -3.26+/-0.85 degrees (p<0.05) and at end diastole by -4.16+/-1.28 degrees (p<0.05). A force of 1.8+/-0.2 N was needed to pull the recoiling ascending aorta back to its original position. CONCLUSIONS: The elastic recoil of ascending aorta is balanced by SC, which connect PM to FT and constitute the center of the LV base. Transection of SC narrows AMA and increases the risk of SAM.

Kinetics of heat shock protein 70 synthesis in the human heart after cold cardioplegic arrest.

OBJECTIVE: Protection of the myocardium against ischemia/reperfusion injury is a major challenge in cardiac surgery and cardiology. A cardioprotective role of heat shock proteins (Hsp), in particular Hsp 70, against ischemia has been demonstrated. A prerequisite for clinical exploitation of high Hsp 70 levels in the heart during ischemia is the determination of the efficacy and the kinetics of cardiac Hsp synthesis in vivo. METHODS: We examined Hsp 70 and other immediate early genes, that are induced by cardioplegia and reperfusion, in right atrial biopsies taken from 15 patients during coronary artery bypass grafting. Specimens were obtained before cardioplegia and after ending of reperfusion and subsequently studied by immunohistochemistry and Western blot analyses. RESULTS: Overall Hsp 70 increased 2.0+/-1.1-fold (P<0.01) in the nucleus as well as in the cytosol of myocytes and endothelial cells during open-heart surgery. As determined by comparison to a dilution series of recombinant protein, Hsp 70 levels amounted up to 6 per thousand of total cellular protein. The increase of Hsp 70 correlated well with the duration of cardioplegia and reperfusion (P<0.005) showing a markedly accelerated increase at periods longer than 2 h. Further, the immediate early gene c-Fos also increased 2.4+/-2.2-fold during open-heart surgery (P<0.05), whereas other members of the Hsp family, like Hsp 27 and Hsp 90, showed no significant changes in protein levels during cardioplegia and reperfusion. CONCLUSIONS: These findings demonstrate that protein levels of Hsp 70 in the myocardium increase to significant amounts within few hours after induction. The optimum time point for induction of Hsp 70 appears to be at least 2 h before open-heart surgery.

Pumpless extracorporeal lung assist using an arterio-venous shunt. Applications and limitations.

We report the use of a pumpless extracorporeal lung assist (PECLA) in 70 patients with severe pulmonary failure of various causes. The device was used under rescue conditions in patients with preserved cardiac function. By establishing a shunt between femoral artery and vein using the arterio-venous pressure gradient as the driving force for the blood flow through the oxygenator, PECLA proved to be extremely effective in terms of oxygenation and carbon dioxide removal.

Aortic arch surgery using moderate systemic hypothermia and antegrade cerebral perfusion via the right subclavian artery.

BACKGROUND: Surgery of the aortic arch avoiding profound systemic hypothermia and using antegrade or retrograde cerebral perfusion has recently been popularized. This usually renders the CPB and surgical field set-up more complex. We propose a simple method achieving a similar effect. METHODS: During a 6-month period, 7 patients (median age 72 years) underwent surgery involving the aortic arch with cannulation of the right subclavian artery for arterial return. There were 6 acute type A dissections and one ascending aorta and arch aneurysm. After commencing CPB, the ascending aorta was clamped and reconstruction of aortic valve and root were initiated. Patients were cooled to a tympanic temperature of 25 - 27 degrees C. CPB was then stopped, and the arch was opened and inspected from inside. While resuming arterial perfusion via the right subclavian artery, the arch branches were clamped sequentially from right to left under observation for back flow. Bilateral radial artery pressure and temporal transcutaneous oxygen saturation were always monitored. RESULTS: In all cases, the aortic valve was spared using remodeling and resuspension techniques. 2 complete arch, 2 partial arch and 3 proximal arch replacements were performed. Mean times were 183 (113 - 321) minutes for CPB and 120 (67 - 213) minutes for aortic cross-clamping. Maximal systemic circulatory arrest time was 82 min. One patient died in the hospital due to MRSA sepsis with a normal CCT scan. All others were discharged in good condition. CONCLUSION: The initial experience with this simple technique of antegrade cerebral perfusion avoiding profound systemic hypothermia and the possible disadvantages of femoral artery cannulation appears promising.

Mitral valve incompetence following blunt chest trauma after mitral valve repair. Recognition by three-dimensional echocardiography.

We present a unique case of mitral incompetence following blunt chest trauma in a 46-year-old woman who had undergone successful mitral valve repair 2 years before the accident. Three-dimensional echocardiography revealed the precise pathology, with partial avulsion of the annuloplasty ring and rupture of chordae tendineae.

Oxygenator thrombosis: worst case after development of an abnormal pressure gradient--incidence and pathway.

The development of an abnormally high pressure gradient (APG) before the membrane oxygenator (MO) is a complication that occurs during some extracorporeal circulation (ECC) procedures. The present study deals with the incidence of an APG and discusses a probable causative pathway by comparing surface-coated and uncoated oxygenation systems. Five thousand six hundred and seventeen adult ECCs were carried out (2,581 without and 3,036 with surface coatings). The incidence of an APG, therefore, amounted to 0.03% in the group with coated systems and 4.3% in the uncoated group. In addition, an in vitro study demonstrated significantly reduced adhesion and activation of platelets and leucocytes when the surfaces of the MOs were coated with heparin or polypeptides. The advantages of coating surfaces of ECC devices possibly depend on the selective adsorption of particular plasma proteins. These will presumably form a biocompatible membrane on the surface, and minimize pathological deposit of fibrin, platelets and other blood cells, and, therefore, implicate the prevention of an oxygenator failure.

Recurrent cardiac myxoma: why it occurs. A case report with literature review.

Two years after surgical removal of a right atrial myxoma, recurrences were found in both atria: multiple tumors in the right atrium and one tumor in the left atrium. All were subsequently removed. There was no further recurrence during the following 3 years. We report on an unusual case which, to our knowledge, is the first time that such a case appears in the literature. We also discuss the clinical symptoms, diagnostic aspects, as well as details of a literature review regarding recurring myxoma. We think the recurrence in our case was due to totipotent multicentricity of the tumor. Previous studies showed that the recurrence might be due to the following reasons: inadequate resection, or multifocal pattern behaviour of a benign myxoma, either in the same or in a different location as the primary tumor. Familial disposition may also play a role in recurrent development. The abnormal DNA ploidy pattern of myxoma patients showed a high recurrence.

[Injuries of the heart--diagnosis and therapy]. / Verletzungen des Herzens--Diagnostik und Therapie.

Injuries of the heart are present in 7-12% of all thoracic trauma cases. Most of these (80%) are polytrauma patients. The mechanism of the accident, the localisation of injuries, the physical condition of the patients and the skills of the hospital stuff are determinant factors for the outcome. Hemodynamic instability needs an urgent echocardiography, signs of an obstructive pericardial hematoma and/or progressive bleeding require an urgent operation using a left lateral or mediosternal approach. ECC and cell saving should be available. The contusion of the heart is monitored by ECG and Troponin tests. The application of a "mini" heart-lung machine in difficult situations could be very useful.

Endothelial apoptosis is induced by serum of patients after cardiopulmonary bypass.

OBJECTIVE: Increased serum levels of a multitude of mediators like interleukins, tumor necrosis factor, elastase, adhesion molecules, and endotoxin have been described following cardiopulmonary bypass (CPB). The biological consequences of this complex response are unclear. METHODS: Serum samples of nine patients scheduled for elective coronary artery bypass grafting were obtained preoperatively and 1, 6, and 12 h after weaning from CPB. Additional serum samples were obtained perioperatively from four patients undergoing major lung resection and from four healthy volunteers. The apoptosis-inducing activity of serum samples on endothelial cells was examined using a tissue culture assay system. Endothelial cells were derived from human umbilical cords and incubated for 48 h with serum samples in various dilutions during their second passage. The culture plates were fixed with methanol/acetone and stained with the DNA dye diamidinophenylindole. Apoptotic and normal cells were identified and counted using phase contrast and fluorescence microscopy. RESULTS: The proportion of apoptotic endothelial cells was 5.6-fold higher in culture plates incubated with diluted (30%) serum samples obtained at 6 h after weaning from CPB when compared to plates incubated with preoperative samples (P=0.0077). A smaller effect occurred already at 1 h in some patients, whereas at 12 h after weaning from CPB no increased endothelial apoptosis was observed. No proapoptotic activity was found in preoperative as well as in control samples from patients undergoing lung resection or from healthy volunteers. CONCLUSIONS: Serum of patients after CPB exerts a strong apoptosis inducing activity on human endothelial cells. Apoptotic death of endothelial cells following CPB may be responsible for postoperative vascular and bypass dysfunction including phenomena like increased capillary permeability.

Pumpless extracorporeal lung assist - experience with the first 20 cases.

OBJECTIVE: Long-term extracorporeal lung assist is limited by a significant mechanical blood trauma resulting in bleeding and hemolysis. To reduce the drawbacks of extracorporeal lung assist a new technique has been developed, by which the driving force for the extracorporeal circuit derives from the patients arterio-venous pressure gradient (pumpless extracorporeal lung assist). The aim of this clinical study was to test the feasibilty and effectiveness of pumpless extracorporeal lung assist in patients with acute respiratory distress syndrome. METHODS: Twenty patients (41+/-16 years) with acute respiratory distress syndrome of various causes and failing respirator therapy were enrolled. The minimum hemodynamic requirements included a cardiac output (CO) >6 l/min and mean arterial pressure (MAP) >70 mmHg. Pumpless extracorporeal lung assist was established using a short circuit arterio-venous shunt including a special designed low-resistance membrane oxygenator which was placed between the patients legs. RESULTS: At the time of inclusion FiO(2) in all patients was 1.0 (paO(2) 45.9+/-7 mmHg, paCO(2) 58.9+/-17 mmHg). After 24 h of pumpless extracorporeal lung assist FiO(2) was reduced to 0.8+/-0.1. A significant improvement in oxygenation (paO(2) 84.1+/-21 mmHg, P<0.05) and CO(2) removal (paCO(2) 32.7+/-5 mmHg, P<0.05) was notable. The mean extracorporeal flow was 2.6+/-0.6 l/min, which represented approximately 25% of the patients mean CO (10.8+/-2 l/min). The median assist time was 12+/-8 (1-32) days. Fifteen out of twenty patients were weaned off pumpless extracorporeal lung assist. Five out of twenty patients died while on the system (four sepsis, one ventricular fibrillation). Three out of twenty patients died after successful weaning on day 8, 30, and 50, respectively. Twelve out of twenty patients were discharged in a healthy state (overall survival 60%). Technical problems included thrombosis of the venous cannula (n=5), thrombus formation within the membrane oxygenator (n=2), membrane oxygenator plasma leakage (n=2), and membrane oxygenator contamination with Candida albicans. No bleeding complication was observed. CONCLUSION: Pumpless extracorporeal lung assist is feasible and effective in a selected group of patients with acute respiratory distress syndrome but preserved hemodynamic function. By eliminating the pump and reducing the tubing length blood trauma can be minimized. Being very simple the system entails fewer risks of technical complications and also facilitates nursing care.

First clinical experience with a mechanical valve with silver coating.

BACKGROUND AND AIM OF THE STUDY: The interface between the annulus and sewing cuff is the infectious center of prosthetic valve endocarditis (PVE). To decrease the incidence of PVE, the sewing cuff of the St. Jude Medical (SJM) mechanical heart valve was permanently coated with elemental silver (Silzone coating). In vitro data have supported the antimicrobial efficacy of this coating. METHODS: To study any adverse effects of the silver coating in humans, serum silver levels were determined (by graphite furnace atomic absorption spectrometry) before (baseline) and at five intervals after operation: day 1, day 3, discharge, one month, and two months. Between January and August 1997, 38 patients (71% males) underwent surgical implant of a SJM Masters Series valve with Silzone coating for the aortic valve (n = 29), mitral valve (n = 6), or both valves (n = 3). Five patients (13%) underwent concomitant procedures. Two patients (5%) presented with native active valve endocarditis. RESULTS: There was no hospital mortality or valve-related hospital morbidity. Blood silver concentrations peaked shortly after surgery and then decreased during the postoperative period. Average levels were consistently below 4 parts per billion (ppb). Levels below 10 ppb are considered normal. Follow up was 95% complete. There were no recurrent or new cases of endocarditis. CONCLUSION: These clinical data indicate that the SJM Masters Series valve with Silzone coating performs well. No adverse effects of the silver coating could be detected, and there were no valve-related complications.

Effects of extracorporeal circulation and heparin on the phenotype of platelet surface antigens following heart surgery.

In this prospective study, the time-dependent effects of extracorporeal circulation and heparin-mediated effects on platelet surface antigens in vitro were investigated using whole blood flow cytometry. Blood samples were drawn prior to and following extracorporeal circulation in 89 patients. The response of surface antigen expression (glycoprotein IIb/IIIa, P-selectin, and glycoprotein Ib) with and without in vitro stimulation was measured. A significant correlation of the duration of extracorporeal circulation with the postoperative response of glycoprotein IIb/IIIa, glycoprotein Ib, and P-selectin to in vitro activation was found. Postoperative P-selectin and glycoprotein Ib expression stimulated with ADP correlated to blood loss. Heparin in vitro significantly reduced glycoprotein Ib expression. Heparin, as well as the duration of extracorporeal circulation, independently correlated to phenotypic changes of platelets following extracorporeal circulation. The significant correlation of these variables to postoperative blood loss demonstrates their relevance to platelet function in vivo.