The Treatment of Malignant Pleural Effusion With Permanent Indwelling Pleural Catheters.

BACKGROUND: 40 000 to 60 000 people develop malignant pleural effusion (MPE) in Germany each year. The most common causes are lung cancer and breast cancer. Patients with pleural carcinomatosis have a median survival time of four months. METHODS: We investigated the current health services situation regarding treatment with indwelling pleural catheters (IPC) versus talc pleurodesis (TP) in Germany based on registry data from the Federal Statistical Office, the Pleural Tumor Registry of the German Society for Thoracic Surgery, and the IPC registry of the ewimed GmbH company. In addition, we conducted a selective literature review on IPC and TP. RESULTS: The symptoms of dyspnea and thoracic pressure determine the need for therapy in MPE. Both TP and IPC are effective treatment options for MPE. Both therapeutic procedures are considered equally effective with respect to the relief of dyspnea, post-interventional quality of life, and complication rates. TP yields a higher rate of successful pleurodesis than IPC (relative risk: 1.56; 95% confidence interval: [1.26; 1.92]; p < 0.0001), while patients who receive an IPC stay in the hospital for a shorter time than those who undergo TP (a difference of slightly more than two days). The survival of patients with MPE is not affected by which of the two local therapeutic procedures is chosen. CONCLUSION: The indication for either IPC or TP needs to be determined individually for each patient on the basis of his or her general condition, symptoms, clinical situation ("trapped lung"), and prognosis.

Stent-assisted embolization as "bailout" option in aortic aneurysm.

The authors report two cases of stent-assisted embolization (SAE) in the aorta. In one case, SAE was performed for treatment of a pseudoaneurysm; the procedure consisted of stent placement and embolization with an AMPLATZER Vascular Plug and detachable coils through the stent struts. In the second case, SAE was performed to stop acute bleeding from an aortoureteral fistula. Before SAE in this case, the aortic bifurcation was reconstructed with self-expandable and balloon-expandable stents. SAE was technically successful in both cases. SAE for aortic pathologic processes may be useful in selected cases as an alternative to surgery or endovascular stent-graft therapy.

Anaphylactic reaction after systemic application of aprotinin triggered by aprotinin-containing fibrin sealant.

We report a 67-yr-old male after multiple surgical procedures for treatment of arterial occlusive disease who suffered an anaphylactic reaction after administration of aprotinin (Trasylol) prior to urgent coronary artery bypass surgery. The patient had been treated with aprotinin-containing fibrin sealant in 2004 and in 2007, 2 wk before coronary artery bypass surgery. The postoperative serologic screening revealed positive results for qualitative aprotinin-specific IgG, highly elevated quantitative aprotinin-specific IgG and moderately elevated aprotinin-specific IgE antibodies.

Duration of graft cold ischemia does not affect outcomes in pediatric heart transplant recipients.

BACKGROUND: Utilizing donor hearts with prolonged graft ischemia may extend the donor pool. METHODS AND RESULTS: The medical records of 363 infants and children, aged 1 day to 17 years, transplanted at Loma Linda University between November 1985 and March 2001, were retrospectively reviewed. Fourteen children received organs with prolonged ischemic times (>8 hours)(PIT) compared with 14 with short ischemic times (< or =90 minutes)(SIT). There were no significant differences when comparing donors for gender, age, weight, cause of death, or duration of cardiopulmonary resuscitation. Preoperative donor shortening fraction (%), as determined by echocardiography, was significantly higher in the SIT group (44.5 versus 36.5%; P=0.006). There were no significant differences between PIT and SIT recipients when comparing age at transplant, weight at transplant, waiting time, weight mismatch, postoperative days on ventilator, duration of inotropic support, and hospital stay. Cardiopulmonary bypass time was significantly longer in the PIT group (140.5 versus 80.5 minute; P=0.001). Median length of follow-up for both groups was approximately 5 years. Five grafts were lost in the PIT group; 7 were lost in the SIT group, with 1 early graft loss in each group. Significant posttransplant coronary artery disease was diagnosed in 2 recipients in each group (PIT: 80 and 42; SIT: 84 and 67 months posttransplant). There was no significant difference between groups in actuarial graft survival. Number of rejection episodes and hospital readmissions during the first posttransplantation year did not differ significantly between groups. CONCLUSION: Late outcomes were not adversely affected by donor hearts preserved by single dose cold crystalloid cardioplegia with greater than 8 hours of cold ischemia.

Assessment of minimally invasive direct coronary artery bypass grafting of the left internal thoracic artery by means of magnetic resonance imaging.

OBJECTIVES: We sought to evaluate graft patency, flow, and flow reserve in patients with minimally invasive direct coronary artery bypass surgery of internal thoracic artery grafts by a combined magnetic resonance protocol with a phase-contrast technique and magnetic resonance angiography. METHODS: At 1.5 T (Magnetom Sonata, Siemens), 30 symptomatic patients with 30 left internal thoracic artery grafts were examined 6 years after minimally invasive surgical intervention. Navigator-gated magnetic resonance angiography and contrast-enhanced FLASH-3D magnetic resonance angiography (0.2 mmol gadopentate-diethylene triamine pentetic acid [Gd-DTPA]/kg body weight) was used to assess bypass patency. Phase-contrast flow measurements with retrospective gating were performed in the internal thoracic artery grafts at rest and after stress induction with dipyridamole (0.57 mg/kg body weight). Graft patency was evaluated by means of multidetector computed tomography (Sensation 16, Siemens). RESULTS: Internal thoracic artery grafts were occluded in 5 of 30 patients. In 6 patients the anastomosis to the left anterior descending artery was highly stenotic (>70 % ) at multidetector computed tomography. In patients with regular grafts (multidetector computed tomography), a significant improvement of graft flow ( P < .001) and diastolic/systolic peak velocity ratio ( P < .001) after stress induction was detected. Magnetic resonance angiography combined with flow reserve measurements could differentiate between occluded-stenotic and regular minimally invasive direct coronary artery bypass grafts. CONCLUSIONS: Magnetic resonance imaging allows a combined assessment of bypass patency and flow with flow reserve in patients after the minimally invasive direct coronary artery bypass operation. The protocol of this study might be applicable for the evaluation of graft status in symptomatic patients after revascularization.

Emergency donor heart protection: application of the port access catheter technique using a pig heart transplantation model.

BACKGROUND: Organ shortage limits the number of transplantations, and donor deterioration may precede and often prevent conventional organ preservation. This study evaluates in situ perfusion as a bedside method for cardiac allograft procurement in a large animal model. METHODS: Thirty Landrace pigs (42 +/- 7 kg) were studied. The hearts in the conventional group underwent cardioplegic arrest with University of Wisconsin solution and sodium-hydrogen exchange inhibitor cariporide as an additive; they were explanted and stored on ice before transplantation. In the in situ group, one catheter was placed in the ascending aorta and another in the right atrium. After disconnection from the ventilator, hypoxia caused circulatory arrest. The aorta was endoclamped, and in situ perfusion of the aortic root was maintained with University of Wisconsin solution and cariporide. After explantation, hearts were stored on ice for 120 min. All hearts were implanted according to the Shumway technique. Ventricular pressure and cardiac output were monitored online, and troponin-I was measured intermittently. Two hours after weaning from extracorporal circulation, the animals were killed and histology was performed. RESULTS: Catheters were placed through introducers within 5 min. Functional recovery and histology were comparable between the two techniques. Troponin-I increased in both groups during reperfusion but at a faster rate in the in situ technique (P <0.01). CONCLUSION: In situ perfusion may be suitable for cardiac transplants when donor deterioration requires urgent organ preservation. Catheters can be placed at bedside and modified to achieve multi-organ protection through additional perfusion of the abdominal aorta.

Arterial switch operation with a single coronary artery.

OBJECTIVE: Our purpose was to evaluate the impact of coronary pattern on survival and reintervention in patients who underwent the arterial switch operation with a single coronary artery. METHODS: We conducted a retrospective analysis of 53 patients with a single coronary artery who underwent the arterial switch operation between 1983 and 2000 at Children's Hospital Boston. Recent follow-up information was obtained for 40 of the 46 long-term survivors (mean follow-up 7.3 +/- 4.5 years). RESULTS: Thirty-five patients had a single right coronary artery, with the left coronary artery posterior to the pulmonary artery in 27. Eighteen patients had a single left coronary artery (16 with the right coronary artery anterior to the aorta). Six of 7 total patients who died had a single right coronary artery; all died before 1992. There were 5 early deaths, all with a single right coronary artery, with 4 deaths due to coronary malperfusion. Survivals for all patients were 91% at 6 months and 87% at 1, 5, and 10 years after the arterial switch operation. Survival figures were lower for patients having a single right ostium with the left main coronary artery posterior to the pulmonary artery compared with all other subtypes (P =.02, log-rank test). Seven patients had reintervention, 4 because of right ventricular outflow tract obstruction, 1 for heart transplantation, 1 for mitral valve repair and 1 for pacemaker implantation. Freedom from reintervention for all patients was 96% at 6 months, 92% at 1 year, 86% at 5 years, and 82% at 10 years after the arterial switch operation, with lower rates for patients having a single left ostium with the right coronary artery anterior to the aorta (P =.0003, log-rank test). CONCLUSIONS: In the current era, the arterial switch operation with a single coronary artery can be performed safely irrespective of the coronary anatomy. Risk of reintervention is higher in patients having a single left ostium with the right coronary artery anterior to the aorta.

Outcome after reconstruction of discontinuous pulmonary arteries.

OBJECTIVE: This study was undertaken to determine outcomes of and optimal treatment strategies for reconstruction of congenital or acquired discontinuity of branch pulmonary arteries. METHODS: Between 1985 and 2000 pulmonary artery continuity was established in 102 patients with discontinuous central pulmonary arteries and normal peripheral arborization. Data were obtained retrospectively. RESULTS: Techniques to connect both pulmonary arteries included direct pulmonary artery-pulmonary artery anastomosis (n = 33), tube graft interposition (n = 47), or pulmonary arterial implantation in right ventricular-pulmonary arterial conduits (n = 22). Among patients with biventricular repair (n = 66), survival was 85% +/- 8% at 5 years, and freedom from surgical or interventional pulmonary arterioplasty was 31% +/- 11%. At most recent follow-up, mean branch pulmonary arterial z scores were -0.5 +/- 1.6 (right pulmonary artery) and -1.4 +/- 1.3 (left pulmonary artery). Mean right to left ventricular pressure ratio was 0.61 +/- 0.26, and this value was more than 0.75 in 13 of 58 cases. Fifteen of 51 had a lung perfusion mismatch of more than 75:25, and in 9 of 58 one branch pulmonary artery was occluded. Twenty-two patients who underwent primary establishment of antegrade pulmonary artery flow without previous shunt procedures had comparable survival and reintervention rates, with a tendency toward higher pulmonary arterial z scores and lower right to left ventricular pressure ratios. Among patients with single-ventricle repair (n = 33), 5-year survival was 93% +/- 8% and freedom from pulmonary arterioplasty was 39% +/- 9%. Ten of 19 patients had a lung perfusion mismatch, and one branch pulmonary artery was occluded in 4 of 31. Overall, a direct pulmonary artery anastomosis was associated with better survival (P =.006). The presence of aortopulmonary collaterals was a risk factor for pulmonary artery occlusion (P =.03). CONCLUSION: Good survival can be achieved for patients with pulmonary artery discontinuity, but this requires frequent reinterventions. Direct pulmonary artery- pulmonary artery anastomoses and control of all collateral vessels may further improve outcome.

Sodium-hydrogen inhibitor cariporide (HOE 642) improves in situ protection of hearts from non-heart-beating donors.

BACKGROUND: Reperfusion injury is a vital problem in non-heart-beating donor (NHBD) organs. The sodium-hydrogen inhibitor cariporide is thought to improve cellular integrity after ischemia and reperfusion. Recently, we demonstrated the possibility of preserving hearts with in situ perfusion after circulatory death. The purpose of this study was to determine whether cariporide improves in situ heart protection. METHODS: We studied 20 pigs (18 +/- 2 kg). Hearts in the conventional group (CON, n = 6) underwent cardioplegic arrest with University of Wisconsin solution and then were explanted and stored for 150 minutes on ice. In the other groups, a catheter was placed in each ascending aorta and right atrium. After disconnecting the ventilator, hypoxia caused circulatory arrest within 7 +/- 2 minutes. The aorta was endoclamped, and continuous in situ perfusion of the aortic root was maintained for 60 minutes with University of Wisconsin solution (UW, n = 7) or with UW solution and cariporide (CAR, n = 7). After explantation, the hearts were stored on ice for 90 minutes. In all groups, hearts were reperfused with homologous, whole pig blood in an isolated working heart model for 45 minutes. We monitored stroke-work index on-line, intermittently measured troponin I and malondialdehyde, and compared light microscopic examinations among the groups. RESULTS: Stroke-work index was higher in the CAR group compared with the UW group during the last 20 minutes of reperfusion (10(3)dynes x cm x beats(-1)x gm(-1), 6.6 +/- 1.4 vs 4.5 +/- 2.0, p < 0.05), troponin I was lower in the CAR group compared with the UW group (161 +/- 32 ng/ml vs 277 +/- 35 ng/ml, p < 0.05). Results of malondialdehyde and light microscopic examinations were slightly better in the CAR group, without reaching statistical significance. CONCLUSION: Cariporide as an additive to UW solution improves functional recovery and decreases myocardial damage in hearts from NHBDs protected with an in situ perfusion technique.

A non-heart-beating donor model to evaluate functional and morphologic outcomes in resuscitated pig hearts.

A non-heart-beating donor model was considered to examine whether pig hearts from the abattoir could be resuscitated by whole blood reperfusion. For preservation, machine perfusion using University of Wisconsin (UW) solution was compared with storage on ice. Nineteen hearts from abattoir pigs, harvested 25 +/- 3 min after exsanguination, were harvested and transported to the laboratory. Controls (n = 7) were immediately reperfused with homologous whole pig blood in an isolated heart model for 60 min with monitoring of left ventricular developed pressure (LVDP), contractility, and coronary flow. UW solution hearts (UW, n = 6) were perfused for 4 h with 10 degrees C cold UW solution before blood reperfusion. In the cold storage group (CS, n = 6), the organs were stored for an additional 4 h on ice before blood reperfusion. In all hearts, histology was performed after 60 min of blood reperfusion to evaluate myocardial reperfusion injury. All three groups showed significant increases in LVDP (p <.001), although this functional recovery was earliest in the control group and latest in the UW group. Significant declines were observed for both LVDP and contractility from the peak values in each group to the end of blood reperfusion. Coronary flow increased steadily over the time course for the UW group, whereas in the control and CS groups flow increased during the first 15 min of blood reperfusion and then decreased. In the UW and CS groups, there were significant positive correlations between coronary flow and LVDP (p <.001). Microscopic examination revealed no differences between the three groups. Thus, hearts from an abattoir with 25 min of warm ischemic time can be resuscitated. For storage of these organs, continuous machine perfusion with UW solution is superior to cold storage on ice.

Extracorporeal circulation without external clamping and cannulation of the aorta: transventricular placement of a new multifunctional aortic cannula.

BACKGROUND: Stroke is a devastating outcome of coronary artery bypass grafting (CABG). An atherosclerotic ascending aorta is a major risk factor for plaque detachment during cannulation and external clamping in patients undergoing CABG while on extracorporeal circulation (ECC). To avoid external cannulation and clamping we developed and tested a new multifunctional cannula in a pig model. METHODS: The cannula has a double-balloon endoclamping function and is placed via the apex of the left ventricle through the aortic valve in the ascending aorta. It has 2 integrated lines for cardioplegic solution and for venting the left ventricle. In this animal model, a single balloon cannula was used because of the short ascending aorta in pigs. RESULTS: The cannula was placed smoothly and reproducibly with a guide-wire technique. The cardioplegic solution was administered via aortic root perfusion. Weaning from ECC was uneventful, and macroscopic examination did not reveal any damage to the aortic valve. CONCLUSIONS: This cannula could be used in patients with a severe atherosclerotic ascending aorta. The risk of plaque detachment and stroke during ECC might be reduced.

Determination of unknown high-grade atherosclerotic lesions by whole-body cardiovascular imaging: assessment of patients with symptomatic atherosclerotic disease of peripheral arteries.

RATIONALE AND OBJECTIVES: The long-term prospects for patients with peripheral-arterial-occlusive disease (PAOD) must be considered in the context of coexistent generalized atherosclerosis. We sought to determine the added clinical information of noninvasive magnetic resonance imaging (MRI) for detecting asymptomatic atherosclerotic disease in patients already at high risk. MATERIALS AND METHODS: Eighty-four patients (64 men, mean age 66.2 + or - 10.0 years, range 34-84 years) with suspected or known PAOD were examined using a comprehensive cardiovascular MRI protocol. Two experienced observers reviewed all MRIs for the presence of "relevant findings," which were defined as pathology requiring immediate therapy or mid-term follow-up. RESULTS: Assessment of cardiac structures and function in 84 study patients yielded new pathology in 40 (48%) patients, whereas cerebral imaging revealed new findings in 45 (54%) patients. Previously unsuspected vascular findings were evident in 46 (55%) patients. Using the information from the MRIs, in 54 (64%) of patients mid-term follow-up was required, whereas in 7 (8%) patients a change of therapy or immediate treatment was necessary. CONCLUSION: Whole-body cardiovascular MRI is able to detect symptomatic and unsuspected findings in patients with PAOD. This technique was able to detect several vascular abnormalities that necessitated immediate medical attention and intervention in patients already identified as high-risk patients and, therefore, may show an increasing impact to determine individual therapeutic and follow-up concepts.

Neuroprotective effects of erythropoietin during deep hypothermic circulatory arrest.

OBJECTIVE: Permanent mild-to-severe brain injury with neurologic sequelae remains a significant source of postoperative morbidity in cardiovascular surgery. There is increasing evidence that erythropoietin confers neuroprotective effects in various conditions of neuronal damage, such as hypoxia and cerebral ischaemia. Using a surviving porcine model, this study evaluates whether systemic treatment with erythropoietin induces brain protection in deep hypothermic circulatory arrest (DHCA). METHODS: Sixteen pigs (42+/-3 kg) randomly assigned into two groups (n=8) were subjected to 60 min of DHCA at an intracerebral temperature of 20 degrees C. The animals of the erythropietin group were treated perioperatively with 500 IU kg(-1) of recombinant human erythropoietin on 3 consecutive days beginning the day before surgery. Intracerebral monitoring was performed by subcortical microdialysis, brain tissue oxygenation, measurement of brain temperature and intracranial pressure. Neurologic recovery was evaluated daily. Perioperative S100 beta protein serum level was determined. The brains were harvested on the postoperative day 6 after perfusion fixation. Multiple brain regions were investigated histologically for hypoxic-ischaemic damage. RESULTS: The subcortical brain microdialysis detected significant increase of glycerol and lactate concentrations in both groups (P=0.0001) with considerably higher concentrations in the brain of control animals (P=0.011). There were no significant differences in neurological outcome (P=0.15). Erythropoietin-treated animals tended to a more complete and rapid neurological recovery. By contrast, none of the animals in the control group achieved complete neurological recovery. S100 beta protein as a putative marker of cerebral injury tended to be higher in the control group. Brain infarction was detectable in all control animals but only in two erythropoietin-treated animals. CONCLUSION: These results suggest some beneficial neuroprotective effects of erythropoietin in this model of global brain ischaemia induced by 1h of hypothermic circulatory arrest.

Graft protection in bypass surgery: siRNA-mediated silencing of adhesion molecules.

The outcome of patients after coronary bypass grafting is greatly influenced by the type of graft material employed, especially regarding the rate of graft restenosis. Besides direct thrombotic events, the leukocyte-endothelial interaction modulated by adhesion molecules is identified to be the central cause leading to graft alterations. This study deals with a new therapeutic concept in order to achieve superior protection of a new bypass graft by blocking the adhesion molecule expression pathway with RNA interference to inhibit the initial leukocyte adhesion and transmigration. Leukocyte binding to adhesion molecules on activated human venous endothelial cells (HVECs) was determined by video-assisted microscopy in a flow chamber mimicking physiological conditions. The cells under study were sequentially transfected in a nonviral manner with specific short interfering RNA-sequences (siRNA) targeting E-selectin, intercellular adhesion molecule, and vascular adhesion molecule. After stimulation of adhesion molecule expression by tumor necrosis factor, a leukocyte-rich suspension was run through the chamber and the attaching leukocytes were counted. Transfection with specific siRNA targeting three different adhesion molecules resulted in a highly significant reduction of leukocyte attachment to activated HVECs in each case compared to the controls (p < 0.05). Transfection with a mixture out of all three siRNA-sequences showed the lowest leukocyte adhesion (p < 0.05) compared to the controls. siRNA-sequences inhibit the adhesion molecule expression on HVECs in an extremely effective way; not only in a single transfection of specific molecules but also in a parallel transfection of multiple sequences in one transfection. Accordingly, siRNA treatment significantly reduced adhesion of leukocyte cells to HVECs compared to controls. This study showed for the first time an effective knockdown of the leukocyte-endothelium interactions by transfection of HVECs with a cocktail consisting of three highly specific siRNAs against three different endothelial adhesion molecules.

Inhibition of adhesion molecule expression on human venous endothelial cells by non-viral siRNA transfection.

OBJECTIVE: Expression of adhesion molecule receptors on venous endothelial cells crucially influences the fate of venous grafts by mediating leukocyte-endothelium interactions. These interactions include adhesion of leukocytes to the endothelium, followed by transendothelial migration, leading to neointimal hyperplasia (NIH) and finally graft occlusion. Therefore, inhibition of adhesion molecule expression may be a promising strategy to improve the quality of venous grafts. We tested the efficiency of non-viral transfection of human venous endothelial cells (HVEC) with short interfering RNA (siRNA) to specifically down-regulate adhesion molecule expression. METHODS: Primary cultures of HVEC were examined for expression of the adhesion molecules ICAM1, VCAM1 and E-selectin (SELE) after non viral siRNA transfection. Adhesion molecule expression was measured by flow cytometry, real-time polymerase chain reaction and immunoblotting after stimulation with TNF-alpha, an inflammatory cytokine. RESULTS: Non-transfected cells showed a strong increase of adhesion molecule expression following cytokine stimulation (P < 0.01). Upon transfection with specific siRNAs a sixfold decrease in ICAM1 (P < 0.001) and SELE expression and cell positivity (P < 0.05) and a twofold decrease in VCAM1 expression and cell positivity (P < 0.01) P could be observed. SiRNA-mediated gene suppression of adhesion molecules was also reflected by corresponding decreases in adhesion protein and transcript levels. CONCLUSIONS: The expression of adhesion molecules on HVECs can be effectively inhibited by specific siRNAs using a safe, non-viral transfection approach. This is a promising tool to pre-condition venous bypass grafts in order to interfere with endothelium-leukocyte interactions and to prohibit neointima thickening or atherosclerosis, which are regarded to be the most important causes of venous graft failure.

Atherosclerotic disease: whole-body cardiovascular imaging with MR system with 32 receiver channels and total-body surface coil technology--initial clinical results.

In this prospective study, the feasibility of a comprehensive cardiovascular imaging protocol with a dedicated whole-body 1.5-T magnetic resonance (MR) imager with 32 receiver channels in 34 patients with peripheral arterial occlusive disease was evaluated. Informed consent and institutional review board approval were obtained. Three-dimensional MR angiographic data sets were acquired with adapted injection protocol. Cardiac functional imaging and delayed-enhancement imaging were performed, as were fluid-attenuated inversion-recovery imaging of the brain and time-of-flight MR angiography of the intracranial blood vessels. Sensitivity and specificity for depiction of significant vascular stenosis (> 70%) were 96%, with conventional digital subtraction angiography as the standard. Substantial microangiopathic tissue alterations (n = 4) and/or cerebral infarction (n = 4) were diagnosed in seven patients. In seven patients, subendocardial or transmural delayed enhancement was detected in corresponding regions, indicating prior myocardial infarction. Previously unknown findings diagnosed with MR imaging required midterm follow-up or therapy in 24 patients, whereas change of therapy or immediate treatment was necessary in three. For patients suspected of having systemic atherosclerotic disease, comprehensive risk assessment is feasible within 30 minutes.

Forty years of clinical aprotinin use: a review of 124 hypersensitivity reactions.

Since its clinical introduction, the anaphylactic potential of aprotinin has been a major concern. World wide, its use is expanding so there is an increased chance that patients have reexposure from various sources. The risk of anaphylaxis is approximately 2.8% in reexposed patients. From 1963 to 2003, 124 cases of aprotinin-induced anaphylaxis were reported in 61 publications. Eleven patients died. The reexposure interval was less than 3 months in 72% (38 of 53 patients). This review looks at the profile of patients at risk so preventive measures may be taken. Past and future exposures have to be taken into account before any aprotinin administration.

Aptamer-based capture molecules as a novel coating strategy to promote cell adhesion.

The improvement of the cytocompatibility of medical implants is a major goal in biomaterials research. During the last years many researchers worked on the fascinating approach to seed the respective cell types on various artificial substrates before implantation. For instance, cell-seeded implants are supposed to be better candidates for transplantable bone substitutes than conventional artificial bone grafts. To improve cell seeding efficiency and cytocompatibility, we designed a new coating material for medical implants. We used aptamers, highly specific cell binding nucleic acids generated by combinatorial chemistry with an in vitro selection called systematic evolution of exponential enrichment (SELEX). Aptamers do have high binding affinity and selectivity to their target. In our study, human osteoblasts from osteosarcoma tissue were used as a target to create the aptamer. Single aptamer mediated cell sorting assays showed the binding affinity with osteoblasts. Additionally, the aptamers immobilized on tissue culture plates could capture osteoblasts directly and rapidly from the cell solution. This model proves that aptamer coated artificial surfaces can greatly enhance cell adhesion. We assume that this strategy is capable to improve the clinical application of tissue engineered implants.