[Show abstract][Hide abstract] ABSTRACT: Brain death (BD), a non-immunological factor of renal injury, triggers an inflammatory process causing pathological signs of cell death in the kidney, such as necrosis and apoptosis. Kidneys from brain dead donors show lower success rates than kidneys from living donors and one strategy to improve transplantation outcome is to precondition the donors. For the first time, anti-rat thymoglobulin (rATG) was administered in an experimental brain death animal model to evaluate if it could ameliorate histopathological damage and improve organ function. Animals were divided into three groups: V (n=5) ventilated for 2h; BD (n=5) brain death and ventilated for 2h; and BD+rATG (n=5) brain death, ventilated for 2h, rATG was administered during brain death (10mg/kg). We observed lower creatinine levels in treatment groups (means): V, 0·88±0·22 mg/dl; BD, 1·37±0·07 mg/dl; and BD+rATG, 0·64±0·02 mg/dl (BD versus BD+rATG, P<0·001). In the BD group there appeared to be a marked increase of ATN, whereas ATN was decreased significantly in the rATG group (V, 2·25±0·5 versus BD, 4·75±0·5, P<0·01; BD+rATG, 2·75±0·5 versus BD 4·75±0·5 P<0·01). Gene expression was evaluated with reverse transcription-polymerase chain reaction; tumour necrosis factor (TNF)-α, interleukin (IL)-6, C3, CD86 showed no significant difference between groups. Increased IL-10 and decreased CCL2 in BD+rATG compared to BD (both cases P<0·01). Myeloperoxidase was increased significantly after the brain death setting (V: 32±7·5 versus BD: 129±18). Findings suggest that rATG administered to potential donors may ameliorate renal damage caused by BD. These findings could contribute in the search for specific cytoprotective interventions to improve the quality and viability of transplanted organs.
[Show abstract][Hide abstract] ABSTRACT: A major concern in transplantation is the preservation of organ function. Ischemia time and microcirculatory disturbance of the organ cannot be avoided and may result in ischemia reperfusion injury (IRI), increasing the risk of delayed graft function (DGF) and acute and chronic rejection. Anti-thymocyte immunoglobulin (rATG) is a polyclonal antibody preparation with multiple effects when administered to recipients. Our objective has been to evaluate whether the administration of rATG to kidney donors instead of recipients, in an experimental model of syngeneic rat transplantation, ameliorates IRI and facilitates immediate graft function recovery. Urea and creatinine levels and necrosis severity scores were significantly lower in kidneys from donors that had received rATG (urea: control: 211±8mg/dl vs. treatment: 110±15mg/dl, p<0.001; creatinine: control: 4.6±0.24mg/dl vs. treatment: 2.6±0.22mg/dl, p<0.001; necrosis severity scores: control: 2.3 vs. treatment: 1.6, p<0.05). TUNEL staining showed 80±13 positive cells in control group and 9±3 (p<0.001) in treatment group. In situ expression of proinflammatory cytokines TNF-α, IL-6, IL-21 and TGF-β1 was reduced in rATG group (p<0.01); the same was observed for KIM-1 and caspase 8 (p<0.001). Cytoprotective genes Bcl2 and HO-1 were upregulated in situ in treatment group (p<0.001). In situ expression of IL-17, caspase 9, IL-23a, CxCl3 and ICAM1 showed no difference between groups (p>0.05). Findings suggest ATG administered to donors may ameliorate the IRI process in kidney transplantation, expressed by lower necrosis and apoptosis scores and the improvement of renal function, which may be explained through the diminished in situ expression of inflammatory mediators.
[Show abstract][Hide abstract] ABSTRACT: Reperfusion injury remains one of the major problems in transplantation. Repair from ischaemic acute renal failure (ARF) involves stimulation of tubular epithelial cell proliferation. The aim of this exploratory study was to evaluate the effects of preconditioning donor animals with rapamycin and tacrolimus to prevent ischaemia-reperfusion (I/R) injury. Twelve hours before nephrectomy, the donor animals received immunosuppressive drugs. The animals were divided into four groups, as follows: group 1 control: no treatment; group 2: rapamycin (2 mg/kg); group 3 FK506 (0, 3 mg/kg); and group 4: FK506 (0, 3 mg/kg) plus rapamycin (2 mg/kg). The left kidney was removed and after 3 h of cold ischaemia, the graft was transplanted. Twenty-four hours after transplant, the kidney was recovered for histological analysis and cytokine expression. Preconditioning treatment with rapamycin or tacrolimus significantly reduced blood urea nitrogen and creatinine compared with control [blood urea nitrogen (BUN): P < 0·001 versus control and creatinine: P < 0·001 versus control]. A further decrease was observed when rapamycin was combined with tacrolimus. Acute tubular necrosis was decreased significantly in donors treated with immunosuppressants compared with the control group (P < 0·001 versus control). Moreover, the number of apoptotic nuclei in the control group was higher compared with the treated groups (P < 0·001 versus control). Surprisingly, only rapamycin preconditioning treatment increased anti-apoptotic Bcl2 levels (P < 0·001). Finally, inflammatory cytokines, such as tumour necrosis factor (TNF)-α and interleukin (IL)-6, showed lower levels in the graft of those animals that had been pretreated with rapamycin or tacrolimus. This exploratory study demonstrates that preconditioning donor animals with rapamycin or tacrolimus improves clinical outcomes and reduce necrosis and apoptosis in kidney I/R injury.
[Show abstract][Hide abstract] ABSTRACT: Ischemia reperfusion injury (IRI) is one of the risk factors for delayed graft function, acute rejection and long term allograft survival after kidney transplantation. IRI is an independent antigen inflammatory process that produces tissue damage. Our objective was to study the impact of immunosuppressive treatment (IS) on IRI applying only one dose of IS before orthotopic kidney autotransplantation.
Twenty-four rats allocated in four groups were studied. One group served as control (G1: autotransplanted rats without IS) and the rest received IS 12 h before kidney autotransplantation (G2: Rapamycin, G3: Mycophenolate mofetil and G4: Tacrolimus).
Improved renal function and systemic inflammatory response were found among IS groups compared to the control group (Delta Urea p<0.0001; Delta Creatinine p<0.0001; Delta C3 p<0.001). The number of apoptotic nuclei in renal medulla in G1 was higher than in IS groups (p<0.0001). Tubular damage was less severe in IS groups respecting G1 (p<0.001). C3, TNF-α and IL-6 expression in kidney samples was reduced when IS was used compared to the control group. No differences were observed among the different immunosuppressive drugs tested. However, Heme oxygenase-1(HO-1) was increased only in Rapamycin treatment.
These data suggest that the use of IS administered before transplant attenuates the IRI process after kidney transplantation in an animal model.
[Show abstract][Hide abstract] ABSTRACT: Ischemia-reperfusion (I/R) injury is one of the risk factors for delayed graft function, acute rejection episodes, and impaired long-term allograft survival after kidney transplantation. This antigen-independent inflammatory process produces tissue damage. Isogeneic transplantation in a rat model is a useful method for study of nonimmunologic risk factors for kidney damage.
To study the effect of sirolimus on I/R injury using only 1 dose of the drug in the donor.
Eighteen rats were allocated to 3 groups of 6 rats each: sham group, control group, and rapamycin group.
Improved renal function and systemic inflammatory response were observed in the rapamycin group compared with the control group (Deltaurea, Deltacreatinine, and DeltaC3, all P < .01). The number of apoptotic nuclei in the renal medulla in the control group was higher than in the rapamycin group (P < .01). Tubular damage was less severe in the rapamycin group compared with the control group (P < .01). Complement 3 and tumor necrosis factor-alpha expression in the kidney samples were significantly decreased when rapamycin was given to the donor rats (P > .01). Bcl-2 protein was upregulated in the rapamycin group compared with the control group (P < .01).
Administration of rapamycin in donors attenuates the I/R injury process after kidney transplantation in a rat model.