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Biomedical subjects

G Steinhoff

Publications and source records attributed to G Steinhoff.

At least 55 records · Page 3Linked to original sources
PubMed1998

Porcine endogenous retrovirus (PERV) was not transmitted from transplanted porcine endothelial cells to baboons in vivo.

The discussion about the clinical risk of zoonoses in xenotransplantation has recently culminated in the demand for a moratorium on clinical organ transplantation using pig donors. The basis for this discussion was a recent report showing a possible trans-species transmission of pig endogenous retrovirus (PERV) by in vitro transfer to human cell lines. At present, it remains unclear if this could also happen in vivo or in the setting of xenotransplantation. Potential in vivo transfer of PERV after xenotransplantation was investigated in an experimental pig-to-baboon cell transplantation model. Baboons were immunosuppressed with high-dose cyclophosphamide (total 45-150 mg/kg) and transplanted with primary porcine aortic endothelial cells (PAEC). Tissue samples (skin, lymph nodes, lung) and peripheral blood leukocytes of 15 baboons, taken about 12-24 months after transplantation of PAEC, were then analyzed by PCR and showed no PERV infection. PERV expression in PAEC was also analyzed: PERV mRNA and reverse transcriptase in the culture supernatant could be detected. In spite of the release of retroviral particles from cultured PAEC, transplantation of these cells into baboon recipients did not result in virus transmission, not even under heavy immunosuppression.

Animals↗
PubMed1998

Cardiac valve endothelial cells: relevance in the long-term function of biologic valve prostheses.

OBJECTIVE: For reasons that are still unclear, biologic heart valve prostheses undergo degeneration after implantation. We studied the possible role of the immune system in this process. METHODS: We examined the expression of immunologically relevant molecules by human cardiac valve endothelium in situ and in vitro and studied re-endothelialization of implanted allogeneic and xenogeneic valvular surfaces using explanted bioprostheses and valves obtained from donor hearts at cardiac retransplantation. RESULTS: We demonstrate that human cardiac valve endothelial cells express molecules capable of initiating immune responses and might therefore play a role in the degeneration of viable cardiac valve prostheses. Also, we show evidence of re-endothelialization on the surfaces of xenografts and allografts but not on valves obtained from previously transplanted hearts. CONCLUSION: Inasmuch as valves from previously transplanted hearts seem to be free from degeneration, we conclude that reduction of the immunogenicity of allograft valve prostheses by HLA matching or immunosuppressive treatment might further improve long-term results after allograft valve replacement.

Antigens, CD↗
PubMed1998

Tissue engineering of heart valves--human endothelial cell seeding of detergent acellularized porcine valves.

OBJECTIVE: Tissue engineering of heart valves represents a new experimental concept to improve current modes of therapy in valvular heart disease. Drawbacks of glutaraldehyde fixed tissue valves or mechanical valves include the short durability or the need for life-long anticoagulation, respectively. Both have in common the inability to grow, which makes valvular heart disease especially problematic in children. The aim of this study was to develop a new methodology for a tissue engineered heart valve combining human cells and a xenogenic acellularized matrix. METHODS: Porcine aortic valves were acellularized by deterging cell extraction using Triton without tanning. Endothelial cells were isolated in parallel from human saphenous veins and expanded in vitro. Specimens of the surface of the acellular matrix were seeded with endothelial cells. Analysis of acellularity was performed by light microscopy and scanning electron microscopy. Cell viability following seeding was assayed by fluorescence staining of viable cells. RESULTS: The acellularization procedure resulted in an almost complete removal of the original cells while the 3D matrix was loosened at interfibrillar zones. However the 3D arrangement of the matrix fibers was grossly maintained. The porcine matrix could be seeded with in vitro expanded human endothelial cells and was maintained in culture for up to 3 days to document the formation of confluent cultures. CONCLUSIONS: Porcine aortic valves can be almost completely acellularized by a non-tanning detergent extraction procedure. The xenogenic matrix was reseeded with human endothelial cells. This approach may eventually lead to the engineering of tissue heart valves repopulated with the patients own autologous cells.

Animals↗
PubMed1998

Ischemic preconditioning as an adjunct to crystalloid or blood cardioplegia for myocardial protection in routine coronary surgery.

Experimental preconditioning is commonly regarded as a powerful protective phenomenon in case of subsequent ischemia. However, little is known about the applicability of preconditioning as an adjunct to cardioplegic myocardial protection in routine coronary surgery. For this reason, a prospective clinical study (611995 to 4/1996) was initiated to evaluate normothermic ischemic preconditioning prior to crystalloid or cold blood cardioplegic arrest. Preconditioning was performed in two cycles of 5 min ischemia and 10 min reperfusion. Four groups of 7 patients each were compared regarding release of troponin T, creatine kinase-myocardial isoform (CK-MB), lactate, and total CK in coronary sinus effluents over a 12-hour period. In the absence of perioperative myocardial infarction, there were no significant differences in these ischemic and metabolic parameters. Unexpectedly, the heed of postoperative pharmacological inotropic support was greater after preconditioning. These results may indicate that ischemic preconditioning as an adjunct to cardioplegic arrest may be associated with impairment of left-ventricular contractility, thus even exerting potentially detrimental functional effects. Overall, the proven beneficial effects of experimental preconditioning seem not to be directly transferable into the clinical settings.

Aged↗
PubMed1998

[Altitude exposure induces hypoxic preconditioning of the heart].

Under in vitro conditions, the resistance to ischemia may be improved by hypoxic preconditioning. This study was designed to test the hypothesis, that hypoxic preconditioning can also be induced in vivo by exposure of an intact animal to simulated high altitude. Male Wister rats (n = 48) were exposed for 60 minutes to simulated high altitude at 3000 m or 5000 m above sea level in a hypobaric chamber. 30, 150 or 300 min following exposure, hearts were excised and perfused aerobically in the working heart model prior to 45 minutes of global ischemia at 30 degrees C and subsequent normothermic reperfusion. For control, hearts of unexposed rats were either preconditioned by one cycle of 5 minutes of normothermic ischemia and reperfusion prior to subsequent ischemia or (n = 8) or not (n = 8). Postischemic measurements included functional parameters such as aortic flow, maximum developed left ventricular pressure, creatine kinase leakage from collected samples of the coronary effluent and the morphometric assessment of the area of myocardium at risk. When compared to non-preconditioning, ischemic preconditioning significantly improved the recovery of aortic flow, left ventricular systolic pressure and reduced the postischemic creatine kinase leakage. Likewise, exposure to a simulated high altitude at 3000 m above sea level significantly improved the recovery of aortic flow and reduced creatinkinase leakage when the time interval between exposure to simulated high altitude and perfusion was set to 150 minutes. Further increase in hypoxic stress (5000 m above sea level) or the reduction of this time interval to 30 minutes reduced postischemic recovery of hearts. The exposure of an intact organism to simulated high altitude can improve the resistance of the heart to ischemia by hypoxic preconditioning. The induction of this beneficial effect depends on the level of hypoxic stress and the time interval between preconditioning and subsequent ischemia.

Altitude↗
PubMed1998

[A new concept for substitutes in vascular surgery].

In a tissue engineering approach to develop vascular grafts without disadvantages such as early thrombosis, neointimal hyperplasia, the inability to grow, aneurysm formation, as well as life-long anticoagulation, decellularized matrix tubes which were obtained by enzymatic cell extraction from a porcine aorta were seeded with human endothelial cells in vitro. This procedure led to completely biological vascular grafts with good handling qualities and sufficient burst strength, presumably suitable for implantation in the arterial circuit.

Animals↗
PubMed1997

Analysis of leukocyte activation during acute rejection of pulmonary allografts in noninfected and cytomegalovirus-infected rats.

After human lung transplantation acute rejection and cytomegalovirus (CMV) infections may occur, probably contributing to the development of chronic rejection. We established a model of subacute allograft rejection in rats to analyze leukocyte activation and effects of a CMV infection. Histoincompatible lung transplants (BN/LEW) without immunosuppression (group A) and lungs of initially immunosuppressed animals (group B) were analyzed. The production of inflammatory mediators (interleukin-6, tumor necrosis factor alpha, nitric oxides) and the expression of MHC class II antigens by alveolar and lung tissue macrophages were significantly enhanced during the alloresponse. In recipients without immunosuppression (group A) allograft necrosis was detected by day 6, whereas group B allografts were fully rejected by day 25. In allografts of immunosuppressed, CMV-infected animals (group C) the CMV infection was clearly aggravated and the number of activated lung tissue macrophages was increased when compared with noninfected allografts or isografts. The subacute model provides the advantage of allowing us to study mechanisms of acute rejection without the effects of reperfusion injury. Furthermore these findings underline the role of inflammatory mediators produced by macrophages during rejection.

Acute Disease↗
PubMed1997

Treatment with monoclonal antibodies to ICAM-1 and LFA-1 in rat heart allograft rejection.

During allograft rejection, leukocyte infiltration in the graft is regulated by various adhesion molecules. Treatment with monoclonal antibodies to ICAM-1 and LFA-1 (CD11 a) induces specific tolerance after murine heart transplantation. In this study, we investigated the possibility of tolerance induction using these antibodies in a fully incompatible rat heart transplant model. Heterotopic, intra-abdominal heart transplantation was performed using Dark Agouti (DA) rats as donors and Lewis (LEW) rats as recipients. Group A (n = 6) received no immunosuppression and served as controls. In group B (n = 6) 500 micrograms/kg per day 1A29 (anti-ICAM-1) was administered intravenously (i.v.) for 5 days; group C rats received the same dosage of WT.1 (anti-CD11 a) i.v. for 5 days. In group D (n = 6), rats received combined i.v. administration of anti-CD11 a and anti-ICAM-1 (500 micrograms/kg per day of each, for 5 days. The antibodies used were monoclonal mouse anti-rat antibodies produced from hybridomas. Allograft survival was monitored by daily palpation of the graft. There was no statistically significant difference in allograft survival between the groups (A: 5.7 +/- 0.5 days; B: 5.7 +/- 0.5 days; C: 5.7 +/- 0.5 days; D: 6.2 +/- 0.4 days). Treatment with monoclonal antibodies to ICAM-1 and LFA-1 alone or in combination had no effect on allograft survival after heart transplantation between fully incompatible rat strains. We conclude that induction of tolerance using these antibodies seems inconceivable in human heart transplantation.

Animals↗
PubMed1997

Lack of in vitro synergy of clinically used antibodies specific for ICAM-1 and LFA-1.

Antibodies blocking adhesion molecules such as leucocyte function antigen (LFA)-1 (CD11a) and intercellular adhesion molecule (ICAM)-1 (CD54) are currently under clinical investigation for rejection prophylaxis in organ transplantation. In a murine model a combined though not a single application of antibodies against LFA-1 and ICAM-1 can induce tolerance towards heart transplants. No information regarding a possible synergistic action in man is as yet available. To fill this blank we tested the immunosuppressive capacity of ANTILFA (alpha-LFA-1)- and BIRR1 (alpha-ICAM-1) on human cells in vitro alone and in combination. Allogeneic venous endothelial cells, the lymphoblastoid cell line MSAB or peripheral blood mononuclear cells were used as stimulation. DNA synthesis, IL-2 production and cytotoxic T cell lysis were measured to assess T cell response. The strongest antibody effects were seen when endothelial cells were used as stimulators with the T cell response being assessed by IL-2 production. Most assays showed a similar immunosuppressive effect of LFA-1 and ICAM-1 blocking while the combination of both antibodies was not significantly more effective than each antibody alone. Thus our data do not provide a rationale for clinical trials using a combination of these antibodies.

Antibodies, Blocking↗
PubMed1997

Anti-rejection prophylaxis by blocking selectin dependent cell adhesion after rat allogeneic and xenogeneic lung transplantation.

OBJECTIVE: Adhesion molecules regulate the infiltration of leukocytes into the graft during rejection after lung transplantation. The first step of the adhesion cascade is mediated by selectins. Sialyl-LewisX is a ligand of P-selectin. The purpose of the study was to evaluate SLX, a synthetic oligosaccharide analog of Sialyl-LewisX, for anti-rejection prophylaxis after allogeneic and xenogeneic left lateral, orthotopic rat lung transplantation. METHODS: In groups A and B, allogeneic lung transplantation was performed using fully incompatible rat strains (donors: Dark-Agouti (RT1a); recipients: Lewis (RT11)). In group A (n = 10), recipients recieved 200 microg/d SLX i.v. on day 0-4. Group B rats (n = 10) served as untreated controls. The animals were sacrificed on days 5 and 10, respectively. In groups C and D, xenogenic lung transplantation was performed using Gold Syrian hamsters as donors and Lewis rats as recipients. In group C (n = 10), recipients received 200 microg/d SLX i.v. on day 0-4. Group D rats (n = 10) served as untreated controls. The animals were sacrificed on days 2 and 5, respectively. Rejection was graded by histology from 0 (no rejection) to 5 (necrosis). By immunhistology, alveolar, interstitial CD11a, CD18 and VLA-4 positive leukocytes were counted. RESULTS: Histologically, there were a lower grade of rejection (A: 2.7 +/- 0.6; B: 4.0 +/- 0.0; P < 0.05) and fewer CD11a positive leukocytes (A: 66 +/- 27; B: 186 +/- 73; P < 0.05) on day 5 in the SLX-treated allograft group compared to the untreated group. In xenotransplantation, SLX also reduced the grade of rejection (C: 3.3 +/- 0.5; D: 4.7 +/- 0.5; P < 0.05) and the number of CD11a positive leukocytes (C: 145 +/- 22; D: 176 +/- 20; P < 0.05) on day 2. CONCLUSIONS: It is concluded, that the administration of SLX significantly reduces allograft rejection. After discontinuation treatment with SLX unmodified rejection appeared. SLX also modifies xenograft rejection, but to a lesser extent, and xenograft necrosis appeared during treatment in this model.

Animals↗
PubMed1997

Ischemic preconditioning prior to myocardial protection with cold blood cardioplegia in coronary surgery.

OBJECTIVE: Encouraging results on myocardial preconditioning in experimental models of infarction, stunning or prolonged ischemia raise the question whether preconditioning techniques may enhance conventional cardioplegic protection used for routine coronary surgery. METHODS: A prospective clinical trial was conducted to investigate the effect of additional ischemic normothermic preconditioning prior to cardioplegic arrest applying cold blood cardioplegia in patients scheduled for routine coronary surgery (3 vessel disease, left ventricular ejection fraction > 50%). Two cross clamp periods of 5 min with the hearts beating in sinus rhythm were applied followed by 10 min of reperfusion, each (n = 7, group I). Inducing moderate hypothermia cold blood cardioplegia was delivered antegradely. In control groups, cold intermittent blood cardioplegia (n = 7, group II) was used alone. Coronary sinus effluents were analyzed for release of creatine kinase (CK), CK-MB, lactate, and troponin T at 1, 3, 6, 9, and 12 h. In addition, postoperative catecholamine requirements were monitored. RESULTS: The procedure was tolerated well, and no perioperative myocardial infarction in any of the groups studied occurred. Concentrations of lactate tended to be higher in group I, but this difference was not significant. In addition, no significant differences for concentrations of CK, CK-MB, and troponin T were found. Following ischemic preconditioning an increased dosage of dopamine was required within the first 12 h postoperatively (group I: 2.63 +/- 1.44 microg/kg/min, group II: 0.89 +/- 1.06 microg/kg/min). CONCLUSIONS: Combining ischemic preconditioning and cardioplegic protection with cold blood cardioplegia does not appear to ameliorate myocardial protection when compared to cardioplegic protection applying cold blood cardioplegia alone. Inversely, contractile function seemed to be impaired when applying this protocol of ischemic preconditioning.

Biomarkers↗
PubMed1997

The lung as a source and a target organ for T- and B-lymphocytes.

In lung transplantation, a substantial number of donor leukocytes are transferred from the donor to the recipient by the graft. Using a rat model, it was analyzed in this study to what extent leukocytes leave the lung, to which phenotype they belong, and to which organs they migrate. The model used was the orthotopic transplantation of the left lung of LEW.7B(RT7b) rats into LEW(RT7a) recipients. Lung allografts are not rejected in this strain combination, which differs only in the RT7 system, a genetic polymorphism of CD45. Using the RT7b marker (monoclonal antibody His41), the distribution of donor leukocytes passively transferred with the graft was studied by immunohistology 2 wk after transplantation. At this time, 2.9 +/- 0.1% (n = 6) of the peripheral blood leukocytes in the recipients were derived from the donor lung. The donor cell population detected in the blood consisted of T cells (59 +/- 4%), B cells (5.1 +/- 0.2%) and a surprisingly high fraction of natural killer (NK) cells (36 +/- 3%). No monocytes or granulocytes were found. In lymph nodes, spleen and thymus donor-derived T- and B-cells could be shown in typical T- and B-areas, respectively. Donor-derived leukocytes were found in the liver and the skin. In the tissue and the bronchoalveolar lavage (BAL) of the host lung, predominantly T cells were found. Furthermore, in the donor tissue and BAL more than 70% of T- and B-cells were host type, demonstrating that the donor lung had been repopulated to a great extent by host lymphocytes. This supports the relevance of BAL as a diagnostic tool in lung diseases. Thus, the lung is an immunologically important site, releasing lymphocytes which migrate to other organs and also attracting many lymphocytes from the circulation.

Animals↗
PubMed1997

Effect of oligosaccharides on rejection and reperfusion injury after lung transplantation.

BACKGROUND: During rejection and reperfusion injury, infiltration of leukocytes into the lung allograft is regulated by adhesion molecules, especially selectins. Sialyl-Lewis X (SLX), an oligosaccharide, is a membrane ligand molecule of P-selectin adhesion receptors. In this study, we investigated the effect of intravenous administration of a synthetic oligosaccharide analog of SLX on rejection and reperfusion injury after rat lung transplantation. METHODS: Left lateral, orthotopic, allogeneic lung transplantation was performed between fully incompatible rat strains (Dark Agouti-->Lewis) after an average total ischemic time of 45 minutes. Group A (n = 6) served as control; no immunosuppression was used. In group B (n = 6), rats received 200 micrograms/kg/day SLX intravenously on days 0 to 4. The animals were killed on days 5 and 10, respectively. In groups C and D, syngeneic lung transplantation was performed (Lewis-->Lewis), with an ischemic time of 7 hours. Group C (n = 6) served as untreated controls. Group D rats (n = 6) received a single dose of 20 mg/kg SLX at the end of the ischemic time. The animals were killed on days 2 and 5, respectively. RESULTS: In group B rats, treated for rejection, a lower grade of rejection (2.7 +/- 0.6 vs 4.0 +/- 0.0, p < 0.05) and fewer infiltrating CD11a-positive leukocytes (6.6 +/- 2.7 vs 18.6 +/- 7.3, p < 0.05) were found histologically compared with group A. In group D rats, treated for reperfusion injury, a significant reduction of reperfusion injury was detected on chest radiograms and by histologic study. CONCLUSIONS: A synthetic oligosaccharide analog of SLX reduces allograft rejection and reperfusion injury by abrogation of P-selectin-dependent leukocyte-endothelial interaction. According to these findings, treatment with oligosaccharides to reduce reperfusion injury and rejection seems to be a promising strategy for clinical lung transplantation.

Animals↗
PubMed1996

Enhancement of cytomegalovirus infection and acute rejection after allogeneic lung transplantation in the rat.

A possible mechanism of the induction of lung transplant rejection by cytomegalovirus (CMV) infection is the inflammatory upregulation of adhesion ligand molecules on transplant endothelia by the viral infection leading to leukocyte activation. To study this question a rat model of rat cytomegalovirus (RCMV) infection and acute lung transplant rejection was established to study: (1) the influence of RCMV infection on the course of rejection, (2) the influence of rejection on the course of RCMV infection, and (3) the influence of RCMV on adhesion molecule expression and leukocyte infiltration. For this Lew (RT1l) rats received either syngenic (n=25) or allogeneic (BN, RT1n; n=38) left lateral lung transplants. Postoperatively, CsA 25mg/kg was given on days 1-3 and triple drug (CsA, Aza, Pred) immunosuppression was given from days 4-10 to induce systemic RCMV infection and acute rejection developed from postoperative day (POD) 15-25 in allogeneic transplants. In RCMV-positive animals the rejection grade was gradually increased at POD 15 and 18. Furthermore, after allogeneic transplantation an enhanced viral infection of the lung transplant as early as POD 11 was found and increased salivary gland PFU titers on days 20 and 25. In the absence of rejection infiltration a maximal induction of ICAM-1 adhesion molecules was found on lung endothelia in RCMV+ allogeneic animals as compared with noninfected controls. This induction was found to lesser degree for VCAM-1 and MHC class II adhesion ligand molecules. This was accompanied by a significantly increased CD11a+ and CD49d+ leukocyte infiltration into the alveolar interstitium on day 11 and 15 in infected transplants. The results show an enhancement of RCMV infection after allogeneic lung transplantation leading to endothelial activation and recruitment of CD11a/CD49d+ leukocytes. This mechanism may strongly influence transplant inflammation and the long-term course of lung transplant rejection.

Animals↗
PubMed1996

Both activated and nonactivated leukocytes from the periphery continuously enter the thymic medulla of adult rats: phenotypes, sources and magnitude of traffic.

Although the thymus is primarily noted for the export of T cells to the periphery, a small influx of cells has also been observed. It is still a matter of debate whether entry into the thymus depends on prior activation. The phenotypes, sources and degree of immigration are largely unknown. We monitored by quantitative immunohistochemistry the entry of cells from the periphery into the rat thymus in three experimental models. We injected i.v. recirculating, small, nonactivated CD4+ T cell subsets, often referred to as naive (CD45RC+) and memory or antigen-experienced (CD45RC-) cells, purified from thoracic duct lymph of allotype-marked donors, allotype-marked leukocytes released from spleen or lung transplants, or leukocytes labeled in the periphery for 12 weeks during the S-phase of the cell cycle by oral application of 5-bromo-2-deoxyuridine (BrdUrd). Early after i.v. injection (0.5 h), significantly more antigen-experienced (CD45RC-) CD4+ T cells entered the thymus, and by 24 h four times as many cells from the CD45RC- subset as from the CD45RC+ subset had entered the thymus and localized to the medulla. None of the thymic entrants expressed the interleukin (IL)-2 receptor. Following spleen transplantation approximately 40% of donor cells entering the thymic medulla were T cells and approximately 55% were B cells. In contrast, from a lung transplant, approximately 85% of peripheral immigrants were T cells and approximately 10% were B cells. After both procedures, a small number of NK cells and monocytes/macrophages were found among the immigrants (< 5%). Rats were fed BrdUrd continuously for 12 weeks, a procedure which labeled approximately 30% of peripheral lymphocytes but not cortical thymocytes. BrdUrd-labeled cells were localized almost exclusively to the thymic medulla and represented approximately 10% of medullary cells. Of the thymic immigrants approximately 50% were T cells, approximately 30% were B cells (including approximately 15% IgD+ cells), approximately 15% were NK cells and the remainder (approximately 5%) were monocytes/macrophages. Only a quarter of BrdUrd-labeled cells expressed the IL-2 receptor. The thymus is continuously infiltrated by both activated and nonactivated leukocytes from the periphery, including T cells, B cells, NK cells and monocytes. These immigrants are supplied by lymphoid and nonlymphoid organs in a characteristic subset composition. Their entry is facilitated by prior antigen experience or activation. Thus, the participation of the thymic medulla in general leukocyte traffic suggests a mechanism by which the T cell repertoire could potentially be modulated by the peripheral tissues.

Animals↗
PubMed1996

Improved endothelial cell attachment on ePTFE vascular grafts pretreated with synthetic RGD-containing peptides.

OBJECTIVES: To assess endothelial cell (EC) attachment in seeding of expanded polytetrafluoroethylene (ePTFE) vascular prostheses by application of a new technique of coupling synthetic RGD-containing peptides with the graft surface. DESIGN: Prospective, open study. SETTING: University Department of Cardiovascular Surgery and Institute of Biochemistry. MATERIALS AND METHODS: ePTFE vascular grafts (group 1) uncoated (group 2) coated with fibronectin (group 3) coated with a RGD-containing peptide or (group 4) coated in a similar way to group 3 but without application of a RGD-peptide, were incubated for 30 min with adult human saphenous vein endothelial cells. After seeding, grafts were exposed to shear stress in an artificial flow circuit. EC attachment after seeding and retention after perfusion was assessed by scanning electron microscopy and image analysis. MAIN RESULTS: Both EC attachment and retention were significantly increased by coating with fibronectin in comparison to uncoated ePTFE. Graft coating with an RGD-peptide lead to the highest increase in EC attachment (30.6% +/- 2.1%) and retention after shear stress (62.9% +/- 7.5%) compared to fibronectin coated (26.0% +/- 3.3%/45.5% +/- 2.1%), uncoated (14.9% +/- 3.1%/13.9% +/- 7.9%) and similar coated ePTFE grafts without application of a RGD-peptide (10.5% +/- 1.1%/6.6% +/- 1.5%). CONCLUSIONS: EC attachment on uncoated ePTFE vascular prostheses is very weak. Our technique of coupling the ePTFE graft surface with cell adhesion promoting RGD-containing synthetic peptides significantly improved this decisive step in endothelial cell seeding of ePTFE grafts.

Adult↗
PubMed1996

Endothelial cell seeding of de-endothelialised human arteries: improvement by adhesion molecule induction and flow-seeding technology.

OBJECTIVES: To assess re-endothelialisation of denuded human arteries by two different seeding techniques using adhesion molecule induction and a dynamic flow-seeding. DESIGN: Prospective, open study. SETTING: University Department of Cardiovascular Surgery. MATERIALS AND METHODS: In the first group (I) segments of human common carotid arteries (n = 4) were balloon-denuded, short-time seeded with cultured adult human venous endothelial cells (EC) and exposed to a mock circulation. In the second group (II) (n = 4), EC were incubated with a synthetic RGD peptide (arginine-glycine-aspartate) prior to seeding with the aim of upregulating the cellular adhesion molecules and increasing EC attachment. In the third group (III) (n = 4), EC were seeded not using the common technique of instillating cells and sequentially rotating the graft but by a dynamic flow application. The percentage of EC-covered luminal surface was assessed by image analysis of scanning electron micrographs. RESULTS: EC attachment was significantly increased in groups II (73%) and III (94%) compared with group I (34%). In group III, a preconfluent monolayer could be established immediately after seeding. One hour of artificial perfusion resulted in no significant EC loss in any of the study groups. CONCLUSIONS: RGD-peptide preincubation improves EC seeding of biological surfaces. Because of accelerated seeding times it may have good potential for clinical applications. The flow-seeding technology may be indispensable if EC seeding of the vascular surface of complete organ systems is required.

Adult↗