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Transplantation Proceedings 10/2002; 34(6):2359-60. · 1.00 Impact Factor
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Transplantation Proceedings 10/2002; 34(6):2213-4. · 1.00 Impact Factor
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Journal of Heart and Lung Transplantation - J HEART LUNG TRANSPLANT. 01/2002; 21(1):137-138.
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ABSTRACT: To improve the quality of organs from brain-dead donors by assessing the influence of alternative strategies on the early behavior of kidneys after transplantation into unmodified hosts.
Kidneys transplanted from living donors perform consistently better than those from cadaver sources. The authors have recently shown that donor brain death produces inflammatory changes in peripheral organs within hours, amplifies coincident ischemia-reperfusion injury, and accelerates acute and chronic rejection. Normalization of the graft by donor hormone treatment has hitherto been unsuccessful.
A standardized rat model of brain death was used. Experimental groups included recipients of allogeneic grafts from living and brain-dead donors (F344-->LEW). Donors were treated immediately after induction of brain death either with intravenous steroids, which block inflammatory cytokine release, or a soluble P-selectin glycoprotein ligand (sPSGL), which blocks initial selectin-mediated cellular adhesion. Kidney grafts were examined serially up to 10 days by morphology, immmunohistology, and reverse transcriptase-polymerase chain reaction.
Overall survival of ummodified recipients of kidneys from brain-dead donors was significantly reduced versus living donors. Animals with organs from brain-dead donors that had received steroids or sPSGL survived significantly longer than those from untreated brain-dead donors. The intensity of ischemia-reperfusion injury and of acute rejection was reduced. Cellular infiltration and transcription of mRNA of representative proinflammatory mediators were diminished.
Treatment of organ donors at the time of brain death markedly improves organ quality after kidney transplantation, upgrading it to that from a living donor.
Annals of Surgery 12/2001; 234(6):732-40. · 7.49 Impact Factor
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ABSTRACT: The clinical observation that the results of kidney grafts from living donors (LD), regardless of relationship with the host, are consistently superior to those of cadavers suggests an effect of brain death (BD) on organ quality and function. This condition triggers a series of nonspecific inflammatory events that increase the intensity of the acute immunologic host responses after transplantation (Tx). Herein are examined the influences of this central injury on late changes in renal transplants in rats. A standardized model of BD was used. Groups included both allografts and isografts from normotensive brain dead donors and anesthetized LD. Renal function was determined every 4 wk after Tx, at which time representative grafts were examined by morphology and by reverse transcriptase-PCR. Long-term survival of brain-dead donor transplants was significantly less than LD grafts. Proteinuria was significantly elevated in recipients of grafts from BD donors versus LD controls as early as 6 wk postoperatively and increased progressively through the 52-wk follow up. These kidneys also showed consistently more intense and progressive deterioration in renal morphology. Changes in isografts from brain-dead donors were less marked and developed at a slower tempo than in allografts but were always greater than those in controls. The transcription of cytokines was significantly increased in all brain-dead donor grafts. Donor BD accelerates the progression of long-term changes associated with kidney Tx and is an important risk factor for chronic rejection. These results explain in part the clinically noted difference in long-term function between organs from cadaver and living sources.
Journal of the American Society of Nephrology 12/2001; 12(11):2474-81. · 9.66 Impact Factor
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ABSTRACT: Clinical organ transplantation has evolved through advances in patient care in parallel with investigations in associated biologies. It has developed from a cottage industry to an important medical specialty driven increasingly by the availability of newer and more effective immunosuppressive drugs, and dependent on consistently close collaborations between university-based clinical scientists and the pharmaceutical industry. Particularly during the past decade, however, this industry has undergone striking changes, consolidating into huge multi-national corporations, each competing for patients, their doctors, and for support of the allied hospitals. Because of the growth of "Big Pharma," the relationship between academia and industry has changed. There have been many advantages to such mutually dependent interactions. A combination of university-based expertise and the specialized knowledge and resources of industry have produced important scientific gains in drug development. Commercial sponsorship of applied research has been crucial. The orchestration of multicenter controlled clinical drug trials has provided invaluable information about the effectiveness of newer agents. But there are also disadvantages of increasing concern. Indeed, the power of "Big Pharma" in many medical fields including transplantation is such that presentation of data can be delayed, adverse results withheld, and individual investigations hampered. Clinical trials may be protracted to stifle competition. Monetary considerations may transcend common sense. Several measures to enhance the clinical relationship between the pharmaceutical industry and those involved with organ transplantation are suggested, particularly the use of third party advisors in the production of clinical trials, support for more basic research and in the dissemination of results. In this way, the increasingly problematic phenomenon of commercialization of the field of transplantation can be tempered and controlled.
Transplantation 04/2001; 71(5):591-3. · 4.00 Impact Factor
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ABSTRACT: Donor brain death upregulates expression of inflammatory mediators in the heart. It is hypothesized that these nonspecific changes trigger and amplify acute rejection in unmodified recipients compared with hearts from normal living donors. We examined the inflammatory and immunological consequences of gradual-onset donor brain death on cardiac allografts after transplantation.
Functioning hearts were engrafted from normotensive donors after 6 hours of ventilatory support. Hearts from brain-dead rats (Fisher, F344) were rejected significantly earlier (mean+/-SD, 9. 3+/-0.6 days) by their (Lewis) recipients than hearts from living donor controls (11.6+/-0.7 days, P=0.03). The inflammatory response of such organs was accelerated, with rapid expression of cytokines, chemokines, and adhesion molecules and brisk infiltration of associated leukocyte populations. Upregulation of major histocompatibility class II antigens increased organ immunogenicity. Acute rejection evolved in hearts from brain-dead donors more intensely and at a significantly faster rate than in controls.
Donor brain death is deleterious to transplanted hearts. The resultant upregulation of inflammatory factors provokes host immune mechanisms and accelerates the acute rejection process in unmodified hosts.
Circulation 12/2000; 102(19):2426-33. · 14.74 Impact Factor
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ABSTRACT: Chronic rejection remains the major obstacle to long-term allograft survival. Detailed understanding of putative etiologic risk factors, both antigen-dependent and -independent, is important for designing effective therapeutic strategies to ameliorate this process. Cell senescence may be an important factor in chronic rejection.
Current Opinion in Immunology 11/2000; 12(5):517-21. · 9.52 Impact Factor
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ABSTRACT: To define the potential influences of donor brain death on organs used for transplantation.
Donor brain death causes prompt upregulation of inflammatory mediators on peripheral organs. It is hypothesized that this antigen-independent insult may influence the rate and intensity of host alloresponsiveness after engraftment.
The rates of survival of unmodified Lew recipients sustained by kidney allografts from brain-dead, normal anesthetized, and anesthetized ventilated F344 donors were compared. Brain death was induced by gradually increasing intracranial pressure under electroencephalographic control. Tracheotomized brain-dead animals and anesthetized controls were mechanically ventilated for 6 hours before transplant nephrectomy. The rate and intensity of the acute rejection event were examined by histology, immunohistology, and reverse transcriptase-polymerase chain reaction.
Animals bearing kidneys from brain-dead donors died of renal failure secondary to acute rejection at a significantly faster rate than those from anesthetized living controls or anesthetized animals ventilated for 6 hours. Within 3 hours after placement and reperfusion of brain-dead donor grafts, significant neutrophil infiltration was observed, followed by increasing numbers of macrophages and T cells. mRNA of proinflammatory mediators detected in kidneys within 6 hours of brain death and upregulated even before transplantation increased thereafter and appeared to accelerate and amplify host alloresponsiveness, as manifested by the rapid expression of chemokines, cytokines, adhesion molecules, and major histocompatibility complex class II antigens in the engrafted organ. The process evolved in the controls less intensely and at a slower rate.
Donor brain death is a significant risk factor for peripheral organs used for transplantation. The activated state of such organs appears to trigger host immune mechanisms that accelerate the process of acute rejection. The effects of this central injury may explain in part the less satisfactory performance of cadaver organs in human transplantation compared with those from living sources.
Annals of Surgery 09/2000; 232(2):263-71. · 7.49 Impact Factor
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ABSTRACT: We sought to assess the effects of angiotensin receptor blockade on glomerular hypertension, macrophage recruitment, and cytokine expression, all of which contribute to the development of chronic graft injury in this model.
The effects of treatment with the specific angiotensin II type 1 (AT1) receptor antagonist, losartan, were assessed over 24 weeks in F344-->LEW rats (LOS, N = 9) versus vehicle-treated F344-->LEW controls (CON, N = 9).
UprotV rose progressively in CON (from 7.0 +/- 2.9 to 41 +/- 17 mg/day at 24 wk) but remained at baseline in LOS (4.2 +/- 0.6 to 9.4 +/- 1.3 mg/day, P < 0.05 vs. CON). Glomerular capillary pressure (PGC) was increased in CON (71 +/- 1 mm Hg at week 20), but remained within the normal range in LOS rats (54 +/- 2 mm Hg, P < 0.05). Glomerulosclerosis averaged 0.3 +/- 0.2% in LOS versus 4 +/- 2% in CON rats (P < 0.05). Tubulointerstitial injury was minimal in both LOS and CON rats (+). The overexpression of renal cortical cytokine mRNA levels for the monocyte chemoattractants, monocyte chemoattractant protein-1 (MCP-1) and RANTES, as well as interleukin-1, inducible nitric oxide synthase, and transforming growth factor-beta, assessed by competitive reverse transcription-polymerase chain reaction, was suppressed in LOS versus CON rats at 20 weeks. Macrophage and T-cell numbers were decreased, and MCP-1, RANTES, and intercellular adhesion molecule-1 staining in the graft, identified by immunohistochemistry, were attenuated in LOS versus CON rats.
The renoprotective effects of losartan in F344-->LEW rats were associated with lowered PGC, inhibition of macrophage chemoattractants and recruitment, and suppression of macrophage-associated cytokines at 20 weeks. These findings suggest that chronic allograft injury in F344-->LEW rats is, to a large extent, mediated by angiotensin II-dependent mechanisms and that these involve glomerular hemodynamics, macrophages, and macrophage-associated cytokines.
Kidney International 07/2000; 57(6):2618-25. · 6.61 Impact Factor
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The Journal of Heart and Lung Transplantation 06/2000; 19(5):414-8. · 4.33 Impact Factor
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ABSTRACT: The relatively few studies that have examined the systemic events after brain death have primarily involved large animals. For more precise definition of the physiology of this central catastrophe and its influence on peripheral organs, we have established a reproduceable model of gradual onset brain death in rats.
The central injury is induced by graded inflation of a Fogarty catheter placed intracranially under EEG and blood pressure monitoring. The rats were mechanically ventilated for 6 hr before removal of their kidneys. Complications and mortality are discussed.
The majority (83%) of the 100 experimental animals could be used as organ donors. After a transient period of autonomic storm, the mean arterial blood pressure remained consistently between 80-100 mmHg, not appreciably different from controls. Despite normotension, the transplanted kidneys from brain dead donors showed a significantly longer interval to regain uniform cortical color and turgor than kidneys from control animals.
We describe a controlled model of gradual onset brain death in the rat in which normotension can be sustained for several hours before the kidneys are removed for transplantation. Despite stable donor blood pressure, ischemia of peripheral organs may explain in part the increased incidence of delayed graft function of cadaver kidneys compared with those from living donors. This model is suitable for transplant-related studies involving organs from donors with irreversible central injury.
Transplantation 03/2000; 69(3):427-30. · 4.00 Impact Factor
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ABSTRACT: Brain death (BD) has been thought to influence the early course of transplanted organs by triggering a series of nonspecific inflammatory events that in turn may increase the kinetics and intensity of the immunological host responses. In this study early nonspecific, cellular, and molecular changes occurring in kidney isografts from BD donors are compared with those from normal anesthetized, ventilated controls.
After induction of brain death, the animals were mechanically ventilated for 6 hr before organ removal. Only rats with stable blood pressure (mean arterial pressure >80 mmHg) were included. Serum creatinines were measured daily. Representative grafts were harvested 6 hr after brain death and between 1 hr and 5 days after engraftment for morphology, immunohistology, and reverse transcriptase-polymerase chain reaction. The presence of serum cytokines was assessed by enzyme linked immunoabsorbant assay.
Serum creatinine levels rose slightly in recipients from BD donors. Serum interleukin-1beta levels increased within 6 hr versus controls (P<0.05). mRNA levels of interleukin-1beta and macrophage inhibitory protein-1 in the kidneys were up-regulated transiently before engraftment (6 hr after BD) and 1 hr after revascularization (P<0.05). By immunohistology, numbers of infiltrating polymorphonuclear leukocytes peaked at 24 hr in parallel with intragraft induction of P- and E-selectin, complement, and other proinflammatory chemokines and cytokines. At 5 days, the isografts from BD donors were highly infiltrated by host leukocyte populations associated with intense up-regulation of their products. In contrast, those from control donors remained relatively normal through this initial follow-up period.
The intense nonimmune inflammation produced in isografts after donor BD may represent the initial stages of a continuum between an initial nonspecific and later immune reactivity, when placed in the context of allotransplantation.
Transplantation 02/2000; 69(3):405-10. · 4.00 Impact Factor
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ABSTRACT: Long-term survival rates of solid organ allografts have improved relatively little during the transplant experience despite more effective immunosuppression, better organ preservation techniques and advances in perioperative management. Because grafts of potentially diminished quality are increasingly accepted to reduce the severe shortage of organs, it has become apparent that a variety of donor-associated risk factors may influence adversely their short and long-term outcome. Recent interest has focused particularly on systemic changes occurring after donor brain death (BD). Numbers of experimental and clinical studies have elucidated the complexities of the hemodynamic, metabolic, neurohormonal, and other physiological alterations following this devastating central injury. This article will address the potential derangements in peripheral organs which may influence their behavior after transplantation.
Annals of transplantation: quarterly of the Polish Transplantation Society 02/2000; 5(4):61-7. · 2.02 Impact Factor
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ABSTRACT: I/R is an important non-specific, antigen independent event, which significantly influences the outcome of transplanted organs. Increasing graft immunogenicity and host alloresponsiveness inflicts additional deleterious effects. Ischemia has also been associated with donor conditions such as brain death and the non-heart-beating donor. As an event surrounding organ procurement, preservation and revascularization occurring early in the transplant process, it initiates a cascade of molecular and cellular events which trigger the release of proinflammatory mediators and attraction of various cell types infiltrating the tissues. This inflammatory event influences both acute functional and structural changes in the organ which contributes to reduced graft survival. Eventually, attenuation of I/R by strategies targeting various mediators and cell populations at different levels of the inflammatory cascade may constitute a means to improve both short and long-term success of solid organ grafts.
Annals of transplantation: quarterly of the Polish Transplantation Society 02/2000; 5(4):29-35. · 2.02 Impact Factor
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Journal of the American Society of Nephrology 12/1999; 10(11):2454-63. · 9.66 Impact Factor
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Clinical Transplantation 09/1999; 13(4):281-6. · 1.67 Impact Factor
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ABSTRACT: We have shown previously that sPSGL, a soluble glycoprotein ligand for P and E selectins, reduces the events associated with ischemia/reperfusion injury of the kidney. In the present study, we have attempted to modulate differentially early inflammatory influences and later host alloresponsiveness in an LBNF1-Lewis renal graft model by treatment with sPSGL in combination with a marginally effective dose of cyclosporine (CsA).
Four experimental groups were studied: group 1=control animals receiving vehicle only; group 2=sPSGL monotherapy alone; group 3=low-dose CsA; group 4=sPSGL plus low-dose CsA. Grafts were removed at 1, 3, 5, and 7 days (n=3/time point) and assessed by histology, immunohistology, and reverse transcriptase-polymerase chain reaction. Long-surviving grafts in recipients of groups 3 and 4 were followed functionally for more than 28 weeks.
Graft function was prolonged indefinitely in recipients in group 4, all of which survived for more than 200 days. In contrast, survival of animals in groups 1 and 2 was not increased substantially, whereas only 4 of 17 animals in group 3 (23.5%) survived more than 24 days (P<0.01). Five days after engraftment, necrosis was relatively minimal in group 4 organs but pronounced in those of the other groups. By immunohistology, numbers of infiltrating CD4+ and CD8+ T cells and ED1+ macrophages were significantly diminished in group 4 allografts compared with those of the other groups. Serial assessment of chemokine and cytokine mRNA expression confirmed these findings. The long-term effects of CsA treatment alone were compared with those of sPSGL in combination with CsA. Proteinuria remained virtually absent in group 4 recipients. Morphologically, the few long-surviving grafts in group 3 showed signs of chronic rejection; those in group 4 remained relatively normal.
Although treatment with sPSGL alone showed no apparent influence on the acutely rejecting transplants, at least by the parameters examined in this study, it produced indefinite survival of kidney grafts when used in combination with low-dose CsA. The data support the influence of early nonspecific injury on later immunological rejection.
Transplantation 05/1999; 67(9):1255-61. · 4.00 Impact Factor
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Transplantation 03/1999; 67(3):343-8. · 4.00 Impact Factor
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Transplantation 01/1999; 67(3):343-348. · 4.00 Impact Factor
