Donor age and delayed graft function as predictors of renal allograft survival in rejection-free patients

Late renal allograft failure between 1990 and 1998 in Spain: a changing scenario

BACKGROUND

Our aim was to study time-dependent modifications in the characteristics of renal transplants in Spain during the 1990s and risk factors associated with death-censored graft failure after the first year.

METHODS

A total of 3,365 adult patients who underwent transplantation in 1990, 1994, and 1998 with a functioning graft after the first year were included.

RESULTS

Ten-year patient and graft survival rates were 82% and 70%. Major modifications between 1990 and 1998 were increases in donor age (32 +/- 15 to 43 +/- 18 years, P<0.0001) and number of HLA mismatches (2.8 +/- 1.2 to 3.2 +/- 1.2, P<0.0001). Acute rejection decreased from 39% to 25% (P<0.0001), and the prevalence recipients with hepatitis C virus decreased from 29% to 10% (P<0.0001). The use of lipid-lowering agents during the first year increased from 6% to 41% (P<0.0001). Projected renal allograft half-life estimate was 15.4 (range, 14.1-16.8) years in 1990 and 17.7 (range, 14.0-21.4) in 1998 (P=0.007). Independent variables associated with graft survival were as follows: recipient age, last panel-reactive antibodies, acute rejection, hepatitis C virus antibodies in the recipient, triglycerides, serum creatinine and proteinuria at 3 months, and the increase of serum creatinine and proteinuria between the 3rd and 12th month. The use of statins during the first year was associated with a decreased risk for graft loss.

CONCLUSION

Despite worsening of surrogate parameters of renal quality and poorer HLA matching, graft survival improved during the 1990s in Spain.

Calcineurin inhibitor-free immunosuppression based on antithymocyte globulin and mycophenolate mofetil in cadaveric kidney transplantation: results after 5 years

Kidney grafts from suboptimal donors are more likely to suffer the nephrotoxic side-effects of cyclosporine than kidneys from standard donors. In an attempt to avoid the use of cyclosporine, we carried out a prospective study in low-immunological risk recipients of suboptimal kidneys, using an immunosuppressive protocol combining Thymoglobuline in induction with a bi-therapy of mycophenolate mofetil (MMF) and steroids. Patients with panel reactive antibodies (PRA) <50% receiving a first renal transplant from a suboptimal donor (age >or=50, non heart beating, arterial hypertension, or acute renal failure) or a kidney at risk of delayed graft function (DGF) because of a prolonged cold ischaemia time (CIT) of 24 h or more, were eligible for this trial. Between September 1996 and December 1999, 30 patients were enrolled for the trial and treated with MMF 2 g orally, pre-operatively, and 3 g daily, post-operatively; Thymoglobuline 2 mg/kg IV pre-operatively, 1.5 mg/kg IV the next day, and for doses of 1 mg/kg IV given on alternate days; and prednisolone 0.25 mg/kg per day, reduced progressively from the end of the first month to 0.1 mg/kg per day by 3 months post-transplant. Cyclosporine was added only if rejection grade II or higher, or a reduction in MMF below 1 g daily, occurred. Ten patients (30%) suffered from DGF, and one kidney suffered primary non function. Seven patients (24%) suffered acute rejection (six were biopsy proven, 3 grade I and 3 grade II). MMF dosage was reduced in 28 patients because of adverse events, and calcineurin inhibitors were introduced in 16 patients. There were 14 episodes of opportunistic infection (cytomegalovirus (CMV 10), Herpes zoster 2, Listeria monocytogenes 1, Pseudomonas aeuruginosa 1), and 7 malignancies (skin 2, thyroid 1, lung 1, Kaposi's sarcoma 2, post-transplantation lymphoproliferative disorder 1). Mean serum creatinine was 178, 199, 213, and 218 micromol/l at 1, 2, 3 and 5 years after transplantation, respectively. Actuarial patient and graft (after censoring for death) survival was 94% and 83% after 1 year and 79% and 65% after 5 years, respectively. These results show that with the combination of MMF, Thymoglobuline and steroids the use of cyclosporine can be delayed, and in a few cases completely avoided, with good efficacy in terms of prevention of rejection and recovery of renal function. Regardless of acceptable patient and graft survival, side-effects of MMF at the doses used in this protocol were common and led to overimmunosuppression in the long-term. Starting MMF at low dose, MPA monitoring and probably CMV prophylaxis may improve the results of this regimen.

[Analysis of the reasons for non graft initial function in our series of the last eleven years]

FUNDAMENTAL: [corrected] To know which risk factor of delayed graft function in our patients.

MATERIAL AND METHODS

We analyzed 469 transplants, 270 had good initial function and 199 had delayed function graft. Variables studies in booth groups were: age, sex and dead cause of donant, type of extraction and place were it was done, implantation side, vases multiple, isquemia times, age and receptor sex, HLA compatibility, retransplant, Ac Anti-VHC, PTH pretransplant, years in waiting list, hiperinmunization, number of transfusion, and type of inmunosupretion.

RESULTS

Univariant study: significant differences were found in age and dead cause of donant, isquemia times, years in waiting list, hiperinmunization, number of transfusions, and HLA-B incompatibility. Multivariate study: we have significant differences in age of donant, could isquemia time, years in waiting list, cuadruple? Inmunosupretion.

CONCLUSIONS

Results suggest to short could and revascularization isquemia time as possible, and use less nefrotoxic inmunosupretion pautes in high-risk patients.

Vascular complications after live donor renal transplantation: study of risk factors and effects on graft and patient survival

We evaluated the incidence and management of vascular complications after live donor renal transplantation. Possible risk factors and their effects on patient and graft survival were also assessed.

MATERIALS AND METHODS

A total of 1,200 consecutive live donor renal transplants were performed in 1,152 patients at a single institution. The incidence of different types of vascular complications were determined and correlated with relevant risk factors. The impact on patient and graft survival was also studied.

RESULTS

There were 34 vascular complications (2.8%). Stenotic or thrombotic complications were recorded in 11 cases (0.9%), including renal artery stenosis in 5 (0.4%), renal artery thrombosis in 5 (0.4%) and renal vein thrombosis in 1 (0.1%). Hemorrhagic complications were observed in 23 patients (1.9%). Although no risk factors could be identified that were related to stenotic or thrombotic complications, grafts with multiple renal arteries were significantly associated with hemorrhagic complications (p = 0.04). Stenotic and thrombotic complications as well as hemorrhagic complications were significantly associated with subsequent biopsy proved acute tubular necrosis (p <0.001). The mean 5-year patient and graft survival rates +/- SD for those with vascular complications were 71.9% +/- 1.9% and 41.6% +/- 8.9% compared with 86.3% +/- 1.1% and 76.8% +/- 1.4% for the remainder of our transplant population, respectively (p <0.001). The deleterious impact on survival was not only observed in recipients with thrombotic or stenotic crises, but also in those with hemorrhagic sequelae.

CONCLUSIONS

Hemorrhagic crises are as serious as the stenotic and thrombotic complications affecting patient and graft survival. Because they are a significant factor in the development of hemorrhagic complications, grafts with multiple renal arteries should be managed critically.

Donor tissue characteristics influence cadaver kidney transplant function and graft survival but not rejection

Acute injury and age are characteristics of transplanted tissue that influence many aspects of the course of a renal allograft. The influence of donor tissue characteristics on outcomes can be analyzed by studying pairing, the extent to which two kidneys retrieved from the same cadaver donor manifest similar outcomes. Pairing studies help to define the relative role of donor-related factors (among pairs) versus non-donor factors (within pairs). This study analyzed graft survival for 220 pairs of cadaveric kidneys for the similarity of parameters reflecting function and rejection. It also examined whether the performance of one kidney was predicted by the course of its "mate," the other kidney from that donor. Parameters reflecting function showed sustained pairing posttransplantation, as did graft survival. In contrast, measures of rejection strongly affected survival but showed no pairing. Surprisingly, the survival of a kidney was predicted by the early performance of its mate, an observation we term the "mate effect." Six-month graft survival and renal function were reduced in grafts for which the mate kidney displayed any criteria for functional impairment (dialysis dependency, low urine output [</=1 L] in the first 24 h posttransplant or day-7 serum creatinine >/= 400 micro mol/L), even for kidneys which themselves lacked those criteria. Rejection measures did not demonstrate the mate effect. In conclusion, kidney transplant function is strongly linked to donor-related factors (age, brain death). In contrast, rejection affects survival and function, but it is not primarily determined by the characteristics of the donor tissue. Graft survival reflects both of these influences.

Silent acute rejection during prolonged delayed graft function reduces kidney allograft survival

BACKGROUND

The relationship between the effects of early, silent, acute rejection (AR) and delayed graft function (DGF) on kidney allograft survival remain controversial, and the role of protocol biopsies during DGF is unclear. We hypothesized that protocol biopsies during DGF would reveal a high incidence of silent AR that may adversely affect long-term allograft survival.

METHODS

We routinely carried out protocol biopsies in patients requiring dialysis 7 to 10 days posttransplant. We retrospectively examined the extent to which silent AR, diagnosed by protocol biopsies during prolonged DGF, may mediate the adverse effects of DGF on graft survival in 410 consecutive transplants using Cox proportional hazards analysis.

RESULTS

By 40 days posttransplant, the cumulative incidence of AR was 57.2% among 65 patients who had a protocol biopsies during DGF, while it was only 15.1% among the 345 who did not need a protocol biopsy. Mild DGF (n=30) requiring one or two dialysis treatments had no effect on graft survival, but the unadjusted risk ratio (and 95% confidence interval) associated with more prolonged DGF (n=104) was 3.08 (2.09-4.52, P<0.0001). The risk for graft failure from AR detected on protocol biopsy was 2.91 (1.60-5.27, P=0.0004) and was similar to the risk from early AR in patients without DGF, 2.95 (1.72-5.07, P<0.0001). After taking the effects of AR into account, the risk of graft failure attributable to prolonged DGF was reduced to 1.76 (1.06-2.94, P=0.0294), suggesting that much of the risk of DGF was because of the risk of AR.

CONCLUSIONS

Silent AR is common during DGF. Prolonged DGF is associated with reduced graft survival after kidney transplantation, and much of this association can be explained by silent AR. In the absence of data from randomized trials, protocol biopsies and treatment of silent AR during prolonged DGF appear to be warranted.

Delayed graft function is characterized by reduced functional mass measured by (99m)Technetium-mercaptoacetyltriglycine renography

BACKGROUND

The mechanism that underlies delayed graft function (DGF) is still poorly defined. Previous studies using tubular function tests have shown that postischemic injury to the renal transplants results in profound impairment of paraimmunohippurate (PAH) extraction through the tubules.

METHODS

Using (99m)Technetium-mercaptoacetyltriglycine ((99m)Tc-MAG3) renography and tubular function slope (TFS), a study of the tubular uptake of (99m)Tc-MAG3 was undertaken in a prospective study of renal transplant recipients with immediate graft function (IGF) and those with DGF.

RESULTS

A total of 37 consecutive recipients of a cadaveric graft and 5 kidneys from living donors was evaluated within 48 hours after transplantation and in week 2, months 3 and 6, and 3 years after transplantation. In addition to the protocol scans, recipients with DGF were examined every other day until function was resumed. Repeated measurement two-way analysis of variance and a change point analysis were performed to determine the difference in the follow-up of TFS values between the two groups. Fourteen patients were classified as having DGF and 28 immediate graft function. In the DGF group, the initial TFS value was significantly lower than in the immediate graft function group (0.54 [+/-0.01] and 1.75 [+/-0.16], respectively; P=0.002), a difference that persisted for up to 3 years. Change point analysis revealed that the postischemic tubular excretion improved with time in both groups in the first 3 to 4 weeks, but both groups remained different up to 3 years after transplantation. Multivariate analysis revealed that only the cold ischemic time was an independent risk factor for a low TFS value. After the initial recovery from postischemic injury, the TFS may be used as a marker for functional renal mass.

CONCLUSION

We propose that the tubular defect in DGF, as defined by (99m)Tc-MAG3 renography, is irreversible and may be a marker of initial graft function.

Elderly donor kidney grafts into young recipients: results at 5 years

BACKGROUND

To date, few data are available on older donor renal grafts transplanted into young recipients. We compare 63 kidneys grafts from donors older than 60 years transplanted into recipients younger than 60 years (group 1) with a control group of 235 patients in whom both recipients and donors were younger than 60 years (group 2).

RESULTS

Patient survival rates at 1 and 5 years, respectively, were 98% and 95% (group 1) and 95% and 84% (group 2) (P=0.01). Graft survival rates were 95% and 83% in group 1 versus 94% and 81% in group 2, although death censoring was significant (100% and 98% group 1 vs. 96% and 86% group 2, P=0.04). In group 1, plasmatic creatinemia was significantly higher. The aged donor, female donor-male recipient combination, and the presence of acute rejection alone or together with acute tubular necrosis, were determinants for worse renal functioning at 1 year after transplantation. Seven patients had chronic nephropathy not related to any clinical parameter.

CONCLUSION

We conclude that kidneys from older donors can be successfully transplanted to younger patients.

Matching older kidneys with older patients does not improve allograft survival

Centers may restrict the use of some donor kidneys on the belief that overall graft survival is improved by giving older kidneys to older recipients and vice versa. The prevalence and the effect on graft survival (determined by death, return to dialysis, or retransplantation) of this practice among 74,297 first cadaver kidney transplantations in 1988 to 1998 was examined by using data from the United States Renal Data System. Giving older kidneys to older recipients is common; recipients > or =55 yr old received donor kidneys that were > or =55 yr old 46.2% more often than expected, but they received kidneys that were 18 to 29 yr old 33.6% less often than expected (chi(2) P < 0.0001). Both recipient and donor age have important effects on graft survival, although the effects of donor age are much stronger than those of recipient age. Compared with recipients 18 to 29 yr old, recipients > or =55 yr old were 25% (95% confidence interval, 15 to 35%, P < 0.0001) more likely to have graft failure (adjusted for donor age and other risk factors). On the other hand, donor kidneys > or =55 yr old were 78% (95% confidence interval, 58 to 99%, P < 0.0001) more likely to fail compared with kidneys 18 to 29 yr old. However, giving older kidneys to older recipients had little independent effect on graft survival, once the intrinsic effects of recipient and donor age were taken into account. For example, transplanting donor kidneys > or =55 yr old into recipients > or =55 yr old reduced the risk of graft failure only -6% (95% confidence interval, -18 to 8%, P = 0.3923) after the independent effects of donor and recipient age per se were taken into account. Thus, giving older kidneys to older recipients is a common practice that does not improve overall graft survival.

Call for revolution: a new approach to describing allograft deterioration

I propose a set of definable entities in the renal transplant course, eliminating the need for the term 'chronic rejection'. The status of a renal transplant can be defined by the presence and extent of rejection (T-cell-mediated or antibody-mediated); allograft nephropathy (parenchymal atrophy, fibrosis, and fibrous intimal thickening in arteries); transplant glomerulopathy; specific diseases; and factors which could accelerate progression. The level of function and the slope of the loss of function should be separately determined. This approach can be applied both in research and in clinical practice, and can be adapted to other organ transplants.

Results of 3-year phase III clinical trials with daclizumab prophylaxis for prevention of acute rejection after renal transplantation

BACKGROUND

Daclizumab (Zenapax, Roche Pharmaceuticals), a humanized monoclonal antibody directed against the alpha chain of the interleukin 2 receptor, has been shown to reduce the incidence of acute rejection at 6 months after renal transplantation in two phase III clinical trials. This report presents the combined 1- and 3-year outcomes of kidney transplant recipients who participated in these two phase III clinical trials.

METHODS

Data from two multicenter, randomized, placebo-controlled trials were evaluated with regard to graft survival, patient survival, incidence of malignancies (including lymphoma), renal function (serum creatinine and glomerular filtration rate [GFR]), and current maintenance immunosuppressive regimen. In addition, the impact of acute rejection and acute rejection requiring treatment with antilymphocyte therapy upon 3-year graft survival was evaluated. Daclizumab was compared to placebo on a background of cyclosporine (CsA), azathioprine, and corticosteroids (triple therapy, TT) or CsA and corticosteroids (double therapy, DT).

RESULTS

Treatment with daclizumab in the pooled analysis demonstrated a significant reduction in the incidence of biopsy-proven acute rejection episodes at 12 months posttransplant (43% vs. 28%, P<0.001). The 3-year graft survival was not significantly different between placebo and daclizumab-treated patients in the TT trial (83% vs. 84%) or in the DT trial (78% vs. 82%). Pooled patient survival was excellent in both placebo- (91%) and daclizumab- (93%) treated patients. The incidence of malignancies or posttransplant lymphoproliferative disorder (PTLD) in placebo- versus daclizumab-treated groups was comparable in both clinical trials. Renal function was similar between placebo- and daclizumab-treated groups in both the TT and DT trials. The occurrence of delayed graft function, acute rejection requiring antilymphocyte therapy at 6 months, and acute rejection at 12 months posttransplant were associated with decreased graft survival rates at 3 years posttransplant.

CONCLUSIONS

The beneficial effect of daclizumab prophylaxis upon the incidence of acute rejection after renal transplant with TT or with DT was not associated with adverse clinical sequelae, including the development of PTLD, at 3 years posttransplant. There was no beneficial effect of daclizumab on graft survival at 3 years, but the trial was inadequately powered to detect this. Both studies showed excellent graft and patient survival at 3 years.

Daclizumab (humanized anti-IL2Ralpha mAb) prophylaxis for prevention of acute rejection in renal transplant recipients with delayed graft function

BACKGROUND

The purpose of this retrospective study was to determine the benefits of daclizumab, (Zenapax, Roche Pharmaceuticals) a humanized anti-interleukin-2Ralpha (IL-2Ralpha) monoclonal antibody, for prevention of acute rejection in renal transplant recipients with delayed graft function (DGF).

METHODS

Data from two multicenter randomized placebo-controlled trials were pooled. DGF was defined by urine output <30 cc/hour, decline in serum creatinine of <0.5 mg/dl, or the need for dialysis within the first 24 hours after transplantation.

RESULTS

At one year posttransplantation, the incidence of biopsy-proven acute rejection in patients with DGF was reduced from 44% in the placebo group to 28% in the daclizumab group. (P=0.03) Prophylaxis with daclizumab also delayed the onset of the first biopsy-proven acute rejection episode in patients with DGF from 29+/-43 days in the placebo group to 73+/-70 days in the daclizumab group. (P=0.004) The graft survival rates in patients with DGF at 1 year posttransplantation were 78% in the placebo group and 82% in the daclizumab treated group. (P=ns) Three patients in the placebo-treated group with DGF experienced graft loss due to acute rejection, whereas no patients in the daclizumab-treated group with DGF had graft loss due to acute rejection. The 1-year patient survival rate in those with DGF in the placebo and daclizumab groups were 93% and 98%, respectively. (P=ns)

CONCLUSIONS

Daclizumab effectively reduced the incidence and delayed the onset of biopsy-proven acute rejection in this high-risk subgroup of patients with DGF after renal transplantation. Graft and patient survival rates were similar between placebo- and daclizumab-treated patients with DGF.

Increased immunogenicity and cause of graft loss of old donor kidneys

Donor age was identified recently as a major factor that determines long-term outcome after transplantation, but the mechanism that is responsible for increased graft loss of old donor kidneys is unknown. The influence of donor age on graft survival was assessed retrospectively in 514 consecutive first cadaveric transplants that were treated with cyclosporine maintenance immunosuppression. Donor age > or =50 yr (relative risk [RR] = 1.7; 95% confidence interval [CI], 1.2 to 2.6), acute rejection (RR = 2.0; 95% CI, 1.3 to 3.0), and type of rejection (RR = 3.3; 95% CI, 2.0 to 5.3) had a significant impact on graft survival. However, when subsets of patients who entered subsequent intervals after transplantation were analyzed, donor age was not an independent predictive factor of graft loss. Donor age (RR = 1.53; 95% CI, 1.19 to 1.98), human leukocyte antigen-DR mismatch (RR = 2.28; 95% CI, 1.78 to 2.92), and recipient age (RR = 1.34; 95% CI, 1.05 to 1.72) were associated significantly with acute rejection episodes. Delayed graft function alone was not associated independently with the occurrence of early acute rejection (RR = 1.24; 95% CI, 0.96 to 1.61). The timing of the rejection episodes of old donor kidneys was not different, and the excess rejection prevalence was attributable entirely to interstitial (grade I) types of rejection. Interstitial rejection episodes in kidneys from old donors had a significant (P < 0.05) negative impact on graft survival. Beyond the first year, poor renal function and proteinuria were significant risk factors for graft loss, regardless of rejection. Our data fit best the hypothesis that increased graft loss of older donor kidneys results from an increased incidence of acute interstitial rejection episodes in the early posttransplantation months. It is proposed that kidneys from older donors are more immunogenic than kidneys from young donors and that acute rejection episodes result in functional deterioration. Contrary to interstitial rejection in kidneys from younger donors, kidneys from old donors seem to have an impaired ability to restore tissue.

Serial protocol biopsies to quantify the progression of chronic transplant nephropathy in stable renal allografts

AIM

To evaluate the utility of intimal thickness and interstitial width as a primary efficacy variable in the design of clinical trials aimed to modify the natural history of chronic allograft nephropathy.

METHODS

A donor and a 4-month protocol biopsy were evaluated in 40 stable grafts according to the Banff schema. In 27 patients, a second protocol biopsy was done at 1 yr. Arterial intimal volume fraction (Vvintima/artery) and cortical interstitial volume fraction (Vvinterstitium/cortex) were estimated with a point counting technique.

RESULTS

Chronic Banff scores increased during follow-up, while acute scores reached its peak at 4 months. Vvintima/artery and Vvinterstitium/cortex significantly increased at 4 months, but not at 1 yr. Vvintima/artery at 4 months correlated with donor Vvintima/artery (r = 0.57, p < 0.001), histocompatibility (r = 0.38, p = 0.01) and serum cholesterol (r = 0.31, p = 0.047). Vvinterstitium/cortex at 4 months correlated with recipient body surface area (r = 0.44, p = 0.004) and delayed graft function (p = 0.016). Power calculations showed that Vvintima/artery and Vvinterstitium/cortex allow an important reduction in minimum sample size of a hypothetical trial aimed to prevent chronic allograft nephropathy.

CONCLUSIONS

Intimal thickening and interstitial widening progresses rapidly during the first 4 months after transplantation and slowly thereafter. These parameters can be considered as a primary efficacy variable in trials aimed to prevent chronic allograft nephropathy.

Eurotransplant Senior Program 'old for old': results from 10 patients

More frequently there is the need for renal transplantation of older patients. Against the background of an increasing number of old donors and recipients, Eurotransplant Leiden started the Eurotransplant Senior Program (ESP) 'old for old' in 1999. The ESP works with donors and recipients both over 65 yr. The kidneys are transplanted with short cold ischaemia time regardless of the human leukocyte antigen (HLA) compatibility. Compatibility of blood groups, negative crossmatch and less than 5% cytotoxic antibodies are required. First experiences from 10 patients at Heinrich Heine University hospital are reported here. The course of 10 transplanted patients is described from January 1999 until November 1999 (28.4+/-15.8 wk). Age of donor and recipient, cause of dialysis and concomitant diseases from recipients, function of the transplanted kidney and complications are analysed. Immunosuppression consisted initially of cyclosporin A, mycophenolic acid and steroids. The results of these 10 patients were compared to 14 patients who were transplanted according to the ordinary Eurotransplant criteria (Eurotransplant Kidney Allocation System) in the same period of time. Kidneys from six donors (70.5+/-3.3 yr) were transplanted to 10 different recipients (66.9+/-2.2 yr). The control group consisted of 14 patients (47.6+/-14.4 yr) who received kidneys from 14 donors (48.3+/-10.1 yr). One double kidney transplantation was performed in the senior group, i.e. two kidneys from a marginal donor were transplanted to one recipient ('two in one'). In the ESP group, cold ischaemia time was reduced by 5 h and mean of HLA mismatches was more than doubled. Mean length of hospitalisation of ESP and control groups was 47.2+/-28.2 and 34.2+/-11.6 d, respectively. Intraoperatively, no complications were seen, post-operative care was performed on a normal ward. ESP patients suffered more often from delayed graft function, which led to further need for haemodialysis for 11.2 d. Finally, 9 of 10 patients acquired a satisfactory renal graft function. A total of 13 biopsies were performed in eight cases. Altogether seven acute rejections in 6 patients were found (four interstitial, one vascular, one interstitial+vascular, one clinical). The 9 patients with sufficient renal graft function were discharged with a mean serum creatinine level of 2.3+/-0.5 mg/dL (control: 1.9+/-0.8 mg/dL). Comparing these 10 recipients to a control group consisting of 14 patients, the results are comparable and encouraging. In conclusion, the short-term results of the ESP are promising. Nevertheless, the post-operative care requires more attention due to several complications. Though the HLA compatibility was not considered, all rejections were coped with effectively. Quality of life was improved.

Influence of nephron mass in development of chronic renal failure after prolonged warm renal ischemia

The present study examined the long-term consequences of warm renal ischemia (WRI) with or without renal ablation. Male Sprague-Dawley rats (250-300 g) were subjected to 60 min of complete WRI by pedicle clamping and then followed for 52 wk. Animals were organized into four groups: rats in which both kidneys were subjected to warm ischemia (2WIK); rats with left WRI and right nephrectomy (1WIK); uninephrectomized rats with a left nonischemic kidney (1NK); and sham-operated rats (2NK). Additional animals were studied at 24 h, 7 days, and 16 and 32 wk. In the first week after WRI, rats from the 2WIK and 1WIK groups displayed a similar degree of acute renal damage. After recovering from acute renal failure, 1WIK rats developed progressive and severe proteinuria, whereas it was mild in the 2WIK group, as well as in the 1NK and 2NK groups. Only animals from the 1WIK group developed severe chronic renal failure, glomerulosclerosis, interstitial fibrosis, and upregulation of transforming growth factor-beta(1) (TGF-beta(1)) gene, which was associated with increased TGF-beta(1) protein expression in tubular epithelial cells, arterioles, and in areas of mononuclear interstitial cell infiltrate. On the contrary, long-term renal TGF-beta(1) expression, function, and histology were similar in 2WIK and 2NK rats. The present study shows that prolonged bilateral WRI, when both kidneys are retained in place, induces very mild long-term renal lesions as opposed to the severe renal scarring observed when WRI is combined with contralateral nephrectomy.

Area under the serum creatinine time-curve is a strong predictor of chronic renal allograft rejection

BACKGROUND

A number of risk factors for chronic renal allograft rejection have been identified; in particular the number and severity of acute rejections, hypertension, hyperlipidemia, and insufficient immunosuppression.

METHODS

In a retrospective case control study, all histologically confirmed cases of chronic rejection (n=45) that occurred between 1985 and 1993 among patients transplanted at Huddinge Hospital were compared with twice as many controls. Determinants such as donor age and sex, HLA-mismatch, cold ischemia time, recipient age and sex, body mass index, cause of renal disease, time undergoing dialysis, condition of blood vessels at surgery, time of onset, number of acute rejection episodes during the first 3 months, area under the serum creatinine versus time curve (AUC(Creatinine)), blood pressure, blood lipids, and cyclosporine concentrations at various times after the transplantation were also compared. Additional data were obtained from a questionnaire, concerning 79% of the cases and controls.

RESULTS

Cases and controls were similar with regard to most determinants, that is, blood pressure, blood lipids, and average cyclosporine concentrations. The main outstanding risk factor for chronic rejection was the time-averaged creatinine (AUC(Creatinine)) value between day 22 and 3 months after transplantation. The adjusted odds ratio for chronic rejection increased stepwise from 1.1 to 9.2, when AUC(Creatinine) increased from < 150 to >300 micromol/l. The number of acute rejection episodes and number of HLA-mismatches also had a significant effect on the risk of chronic rejection.

CONCLUSIONS

To reduce the risk of developing chronic rejection after renal transplantation acute rejection episodes during the first 3 months should be avoided as much as possible.