Adherence to Medical Appointments Among Living Kidney Donors After Donation Under a Monitored Approach and Long-term Clinical Outcomes: A Brazilian Single-center Cohort Study

BACKGROUND

There is little information about living donor long-term follow-up among Brazilian living donors. The aim of this study was to evaluate the main outcomes among living donors and to measure their adherence to regular medical appointments.

METHODS

This is a Brazilian single-center cohort study that included 397 living donors with 87.1 months of follow-up and measured adherence to clinical appointments. Before 2010, the appointments were scheduled only spontaneously; after that an approach was structured to check the returns of donors, who were monitored actively. We also evaluated long-term outcomes such as survival and chronic kidney disease development and, secondarily, the incidences of hypertension, diabetes mellitus (DM), and dyslipidemia after donation.

RESULTS

The donors' adherence to annual clinical appointments was 75.8% (54.7% of them presenting annual regularity). Before 2010 the adherence was lower than 40%; 10-year cumulative incidences of hypertension, DM, and dyslipidemia were 20.4%, 5.7%, and 23.5%, respectively. The crude mortality was 1% and 10-year donor survival was 98.5%. The incidence of chronic kidney disease 5 years after donation was 19%, with 16.4% of patients staged in 3a and 2.6% in 3b.

CONCLUSION

A structured approach to check donor returns to long-term clinical appointments has doubled the adherence to visits returns (compared to historical data). We identified lower incidence of arterial hypertension and DM among donors as compared with the incidence of arterial hypertension and DM in the Brazilian general population, but the 5-year chronic kidney disease incidence was considered high, taking into consideration data that have been published in the last years.

Renal transplantation in human immunodeficiency virus-infected recipients: a case-control study from the Brazilian experience

BACKGROUND

Highly active antiretroviral therapy has turned human immunodeficiency virus (HIV)-infected patients with end-stage renal disease into suitable candidates for renal transplantation. We present the Brazilian experience with kidney transplantation in HIV-infected recipients observed in a multicenter study.

METHODS

HIV-infected kidney transplant recipients and matched controls were evaluated for the incidence of delayed graft function (DGF), acute rejection (AR), infections, graft function, and survival of patients and renal grafts.

RESULTS

Fifty-three HIV-infected recipients and 106 controls were enrolled. Baseline characteristics were similar, but a higher frequency of pre-transplant positivity for hepatitis C virus and cytomegalovirus infections was found in the HIV group. Immunosuppressive regimens did not differ, but a trend was observed toward lower use of anti-thymocyte globulin in the group of HIV-infected recipients (P = 0.079). The HIV-positive recipient group presented a higher incidence of treated AR (P = 0.036) and DGF (P = 0.044). Chronic Kidney Disease Epidemiology Collaboration estimated that glomerular filtration rate was similar at 6 months (P = 0.374) and at 12 months (P = 0.957). The median number of infections per patient was higher in the HIV-infected group (P = 0.018). The 1-year patient survival (P < 0.001) and graft survival (P = 0.004) were lower, but acceptable, in the group of HIV-infected patients.

CONCLUSIONS

In the Brazilian experience, despite somewhat inferior outcomes, kidney transplantation is an adequate therapy for selected HIV-infected recipients.

Comparison of long-term effect of thymoglobulin treatment in patients with a high risk of delayed graft function

BACKGROUND

T-lymphocyte depletion is a strategy to reverse the impact of ischemia-reperfusion injury (IRI) in progression to chronic allograft dysfunction, especially among patients at high risk for delayed graft function (DGF).

METHODS

The present work assessed the effect of thymoglobulin among a population with a high incidence of DGF. We analyzed 209 transplanted patients: 97 in the thymoglobulin and 112 in the control group.

RESULTS

The main complication was DGF (59.3%), with a similar incidence in both groups (63.9% vs. 55.3%; P = .36). Acute rejection episodes (ARE) were decreased with thymoglobulin (8.2% vs. 28.5%; P < .001), but cytomegalovirus viremia was 3.4-fold more frequent (58.3% vs. 17.1%; P < .001). One-year graft function was significantly better in the thymoglobulin group (59.2 ± 17.2 vs. 51.8 ± 15.3 mL/min; P = .004), even when censored by ARE (59.7 ± 17.5 vs. 53.3 ± 14.4; P = .023). The same difference was observed at the 2-year follow-up (P = .024), even when censored for ARE (P = .045). A multivariate analysis showed thymoglobulin to be a factor strongly associated with protection of graft function (P = .039).

CONCLUSION

Despite not reducing the incidence of DGF, thymoglobulin induction significantly reduced the incidence of ARE and showed a long-term profile of protection of renal graft function, independent of the reduction in ARE.

Clinical implications of initial renal function after deceased donor transplant

The aim of this study was to investigate whether slow graft function (SGF) after transplantation of deceased-donor kidneys affected the prevalence of anemia or the glomerular filtration rate (GFR). We retrospectively evaluated the records of 534 kidney transplant patients who were classified based on their initial renal function, namely, immediate graft function (IGF), slow graft function (SGF), or delayed graft function (DGF). Among the 534 kidney transplant patients studied, the occurrences of each condition were IGF 104, SGF 133, and DGF 297. Six months after transplantation, a greater percentage of DGF patients were anemic compared with the others (P = .028). However, at 12 months after transplantation, SGF patients showed more anemia than the IGF group. DGF and SGF patients displayed similar GFR values at 18 and 24 months after transplantation. However, IGF patients displayed higher GFRs, even when subjects who experienced acute rejection episodes were censored (P = .004). The incidence of acute rejection episodes was similar among SGF and DGF patients. Patients displaying SGF after deceased-donor transplantation showed a greater tendency to be anemic than those displaying IGF. This study also suggested that SGF patients were at risk for acute rejection episodes and/or significantly reduced kidney function as measured by GFR.

Glomerular damage as a predictor of renal allograft loss

Interstitial fibrosis and tubular atrophy (IF/TA) are the most common cause of renal graft failure. Chronic transplant glomerulopathy (CTG) is present in approximately 1.5-3.0% of all renal grafts. We retrospectively studied the contribution of CTG and recurrent post-transplant glomerulopathies (RGN) to graft loss. We analyzed 123 patients with chronic renal allograft dysfunction and divided them into three groups: CTG (N = 37), RGN (N = 21), and IF/TA (N = 65). Demographic data were analyzed and the variables related to graft function identified by statistical methods. CTG had a significantly lower allograft survival than IF/TA. In a multivariate analysis, protective factors for allograft outcomes were: use of angiotensin-converting enzyme inhibitor (ACEI; hazard ratio (HR) = 0.12, P = 0.001), mycophenolate mofetil (MMF; HR = 0.17, P = 0.026), hepatitis C virus (HR = 7.29, P = 0.003), delayed graft function (HR = 5.32, P = 0.016), serum creatinine > or =1.5 mg/dL at the 1st year post-transplant (HR = 0.20, P = 0.011), and proteinuria > or =0.5 g/24 h at the 1st year post-transplant (HR = 0.14, P = 0.004). The presence of glomerular damage is a risk factor for allograft loss (HR = 4.55, P = 0.015). The presence of some degree of chronic glomerular damage in addition to the diagnosis of IF/TA was the most important risk factor associated with allograft loss since it could indicate chronic active antibody-mediated rejection. ACEI and MMF were associated with better outcomes, indicating that they might improve graft survival.

Cross-transmission of vancomycin-resistant Enterococcus in patients undergoing dialysis and kidney transplant

The objective of this study was to investigate the occurrence of vancomycin-resistant Enterococcus (VRE) cross-transmission between two patient groups (long-term dialysis and kidney transplant patients). Molecular typing, by automated ribotyping with the RiboPrinter Microbial Characterization System (Qualicon, USA), was used to analyze VRE isolates from 31 fecal samples of 320 dialysis patients and 38 fecal samples of 280 kidney transplant patients. Clonal spread of E. faecalis and E. casseliflavus was observed intragroup, but not between the two groups of patients. In turn, transmission of E. gallinarum and E. faecium between the groups was suggested by the finding of vancomycin-resistant isolates belonging to the same ribogroup in both dialysis and transplant patients. The fact that these patients were colonized by VRE from the same ribogroup in the same health care facility provides evidence for cross-transmission and supports the adoption of stringent infection control measures to prevent dissemination of these bacteria.

Synergistic effect of mycophenolate mofetil and angiotensin-converting enzyme inhibitor in patients with chronic allograft nephropathy

Experimental data and few clinical non-randomized studies have shown that inhibition of the renin-angiotensin system by angiotensin-converting enzyme (ACE) associated or not with the use of mycophenolate mofetil (MMF) could delay or even halt the progression of chronic allograft nephropathy (CAN). In this retrospective historical study, we investigated whether ACE inhibition (ACEI) associated or not with the use of MMF has the same effect in humans as in experimental studies and what factors are associated with a clinical response. A total of 160 transplant patients with biopsy-proven CAN were enrolled. Eighty-one of them were on ACE therapy (G1) and 80 on ACEI_free therapy (G2). Patients were further stratified for the use of MMF. G1 patients showed a marked decrease in proteinuria and stabilized serum creatinine with time. Five-year graft survival after CAN diagnosis was more frequent in G1 (86.9 vs 67.7%; P < 0.05). In patients on ACEI-free therapy, the use of MMF was associated with better graft survival. The use of ACEI therapy protected 79% of the patients against graft loss (OR = 0.079, 95%CI = 0.015-0.426; P = 0.003). ACEI and MMF or the use of MMF alone after CAN diagnosis conferred protection against graft loss. This finding is well correlated with experimental studies in which ACEI and MMF interrupt the progression of chronic allograft dysfunction and injury. The use of ACEI alone or in combination with MMF significantly reduced proteinuria and stabilized serum creatinine, consequently improving renal allograft survival.

Improved renal function after kidney transplantation is associated with heme oxygenase-1 polymorphism

Heme oxygenase-1 (HO-1) has a microsatellite polymorphism based on the number of guanosine-thymidine nucleotide repeats (GT) repeats that regulates expression levels and could have an impact on organ survival post-injury. We correlated HO-1 polymorphism with renal graft function. The HO-1 gene was sequenced (N = 181), and the allelic repeats were divided into subclasses: short repeats (S) (<27 repeats) and long repeats (L) (>/=27 repeats). A total of 47.5% of the donors carried the S allele. The allograft function was statistically improved six months, two and three yr after transplantation in patients receiving kidneys from donors with an S allele. For the recipients carrying the S allele (50.3%), the allograft function was also better throughout the follow-up, but reached statistical significance only three yr after transplantation (p = 0.04). Considering only those patients who had chronic allograft nephropathy (CAN; 74 of 181), allograft function was also better in donors and in recipients carrying the S allele, two and three yr after transplantation (p = 0.03). Recipients of kidney transplantation from donors carrying the S allele presented better function even in the presence of CAN.

Contribution of CD4+ T cells to the early mechanisms of ischemia- reperfusion injury in a mouse model of acute renal failure

Renal ischemia-reperfusion (IR) injury is the major cause of acute renal failure in native and transplanted kidneys. Mononuclear leukocytes have been reported in renal tissue as part of the innate and adaptive responses triggered by IR. We investigated the participation of CD4+ T lymphocytes in the pathogenesis of renal IR injury. Male mice (C57BL/6, 8 to 12 weeks old) were submitted to 45 min of ischemia by renal pedicle clamping followed by reperfusion. We evaluated the role of CD4+ T cells using a monoclonal depleting antibody against CD4 (GK1.5, 50 micro, ip), and class II-major histocompatibility complex molecule knockout mice. Both CD4-depleted groups showed a marked improvement in renal function compared to the ischemic group, despite the fact that GK1.5 mAb treatment promoted a profound CD4 depletion (to less than 5% compared to normal controls) only within the first 24 h after IR. CD4-depleted groups presented a significant improvement in 5-day survival (84 vs 80 vs 39%; antibody treated, knockout mice and non-depleted groups, respectively) and also a significant reduction in the tubular necrosis area with an early tubular regeneration pattern. The peak of CD4-positive cell infiltration occurred on day 2, coinciding with the high expression of betaC mRNA and increased urea levels. CD4 depletion did not alter the CD11b infiltrate or the IFN-gamma and granzyme-B mRNA expression in renal tissue. These data indicate that a CD4+ subset of T lymphocytes may be implicated as key mediators of very early inflammatory responses after renal IR injury and that targeting CD4+ T lymphocytes may yield novel therapies.

High expression of Tim-3 mRNA in urinary cells from kidney transplant recipients with acute rejection

TIM-3 is a recently described molecule specifically expressed on Th1 differentiated T cells. We explored the usefulness of urinary mRNA profiles in the diagnosis of renal acute rejection (AR). Sixty urinary samples from renal transplant recipients simultaneously collected to allograft biopsy, (AR = 30 and No-AR =30), and 12 urinary samples from stable renal transplants were analyzed. Urinary mRNA encoding for TIM-3 and IFN-gamma were quantified using real time RT-PCR. TIM-3 mRNA was highly expressed in AR (559.19 +/- 644.41) compared to No-AR (3.78 +/- 7.20), and stable transplants (0.54 +/- 0.76), p < 0.001. To a lesser degree, IFN-gamma mRNA transcripts were also increased in AR (50.40 +/- 38.71), compared with No-AR (4.69 +/- 12.62), and stable transplants (0.38 +/- 0.44) p < 0.001. The highest expression of TIM-3 in AR makes it a promising noninvasive test for its diagnosis.

A role for HO-1 in renal function impairment in animals subjected to ischemic and reperfusion injury and treated with immunosuppressive drugs

INTRODUCTION

Ischemia/reperfusion injury (IRI) represents the single major antigen-independent factor implicated in pathogenesis of chronic graft dysfunction. Tacrolimus is a calcineurin inhibitor, which has been suggested to be helpful in cyclosporine-related chronic toxicity. Rapamycin has antiproliferative properties that may impair renal regeneration after IRI. Therefore, immunosuppressive drugs might impair renal graft outcome in those organs suffering IRI.

MATERIAL AND METHODS

C57B1/6 male mice subjected to 45 minutes of renal pedicle ligation were reperfused for 24 hours. Mice were treated with rapamycin, cyclosporine, or tacrolimus. Blood and renal tissue samples were collected at 24 hours after IRI. Urea levels were measured. Heme Oxygenase 1 (HO-1) gene transcript was amplified by a real-time polymerase chain reaction technique.

RESULTS

Animals treated with cyclosporine and subjected to IRI showed impaired renal function that peaked at 24 hours. Additional pretreatment with rapamycin produced even more impairment of renal function, when compared with controls. However, tacrolimus pretreatment was associated with a better renal outcome. HO-1 expression was upregulated after IRI by 2.6 arbitrary units at 24 hours. Rapamycin showed worse impairment of renal function.

CONCLUSION

Tacrolimus was not associated with worsening renal function when compared with animals just subjected to IRI. Upregulation of HO-1 may be an attractive approach to limit graft injury.

The role of toll-like receptor 4 in cisplatin-induced renal injury

BACKGROUND

Toll-like receptors recognize pattern-associated molecules found in pathogens as well as in endogen cells and in matrix degradation products. Despite the effectiveness of cisplatin against various solid tumors the administered dose is limited by its nephrotoxicity, namely, induction of tubular cell apoptosis. Herein, we investigated whether the cell toxicity of cisplatin was mediated by toll-like receptor 4 signaling.

METHODS

C3H/He J (Toll-like receptor 4 deficient) and C3H/HePas (control) were treated with cisplatin (20 mg/kg). We evaluated renal function as well as expression of (HO-1) heme oxygenase 1 and MCP-1 mRNAs.

RESULTS

Animals deficient in Toll-like receptor 4 showed less renal dysfunction after cisplatin therapy, which was more evident at later time points. Moreover, MCP-1 mRNA expression in kidneys from these animals were lower than controls, mainly at 96 hours after treatment. No differences were seen in HO-1 mRNA expression.

CONCLUSIONS

These results suggested that cisplatin-induced renal toxicity is mediated in part though toll-like receptor 4.

Mesenchymal stem cells ameliorate tissue damages triggered by renal ischemia and reperfusion injury

BACKGROUND

Ischemia and reperfusion injury (I/R) is the major cause of acute renal failure (ARF) with high mortality rates. Because alternative therapies are needed, we investigated the use of stem cell therapy to modulate inflammation in a renal I/R model.

METHODS

To study kidney I/R injury, we clamped bilateral pedicles for 60 minutes. Mesenchymal stem cells (MSC), which had been isolated and cultivated in plastic flasks, were administered to mice 6 hours after injury. Real-time polymerase chain reaction was used to quantify interleukin (IL)-4 and IL-1beta mRNAs. Proliferative nuclear cell antigen (PCNA) was used to calculate tubular regeneration.

RESULTS

Administration of MSC attenuated renal injury; serum creatinine and plasma urea levels were significantly reduced 24 hours after reperfusion. PCNA immunohistochemistry showed that regeneration occurred faster in renal tissues of animals that received MSC than in tissues of control animals. Analyses of cytokine expression in renal tissue demonstrated a greater level of anti-inflammatory cytokines in MSC-treated animals.

CONCLUSION

These results showed an antiinflammatory pattern in MSC-treated animals, demonstrating the potential of MSC to modulate I/R, leading to earlier regeneration of damaged renal tissue.

Incidence of donor and recipient toll-like receptor-4 polymorphisms in kidney transplantation

Toll-like receptors (TLR) comprise an emerging family that recognize pathogen-associated molecular patterns and promote the activation of leukocytes. Recently, TLR has been demonstrated to play a role in experimental allograft rejection. However, the TLR-4 gene has a polymorphism that can be associated with a blunted immune response, especially to microbial pathogens. We sought to study the incidence of TLR 4 gene variants among renal transplant donors and recipients from living and deceased organs and then to correlate them with short-term and long-term outcomes.

METHODS

Analysis of TLR4 polymorphisms at Asp299Gly and Thr399Ile codons were performed using restriction fragment length polymorphism. Demographic data was obtained from patient records.

RESULTS

Among 201 patients, 141 were recipients from related donors (group 1) and 60 recipients from 45 deceased donors (group 2). Patients were followed for 108 +/- 85 months after transplantation. The incidence of polymorphism for TLR-4 Asp299Gly, Thr399Ile or both were 8.9% in recipients and 8.0% in donors. Patients who received a kidney with polymorphism, Asp299Gly, or Thr399Ile, or both, did not show a difference in rate of acute tubular necrosis compared with controls (no polymorphism). Acute rejection occurred in 17.6% of recipients with Asp299Gly/Thr399Ile polymorphisms and in 39.5% of wild-type recipients (P = .400). The incidence of bacterial infection was equal in both groups.

CONCLUSION

The incidence of polymorphism in this study was similar in both groups, and donor or recipient polymorphisms were not associated with different renal graft outcomes.

The blockade of cyclooxygenases-1 and -2 reduces the effects of hypoxia on endothelial cells

Hypoxia activates endothelial cells by the action of reactive oxygen species generated in part by cyclooxygenases (COX) production enhancing leukocyte transmigration. We investigated the effect of specific COX inhibition on the function of endothelial cells exposed to hypoxia. Mouse immortalized endothelial cells were subjected to 30 min of oxygen deprivation by gas exchange. Acridine orange/ethidium bromide dyes and lactate dehydrogenase activity were used to monitor cell viability. The mRNA of COX-1 and -2 was amplified and semi-quantified before and after hypoxia in cells treated or not with indomethacin, a non-selective COX inhibitor. Expression of RANTES (regulated upon activation, normal T cell expressed and secreted) protein and the protective role of heme oxygenase-1 (HO-1) were also investigated by PCR. Gas exchange decreased partial oxygen pressure (PaO2) by 45.12 +/- 5.85% (from 162 +/- 10 to 73 +/- 7.4 mmHg). Thirty minutes of hypoxia decreased cell viability and enhanced lactate dehydrogenase levels compared to control (73.1 +/- 2.7 vs 91.2 +/- 0.9%, P < 0.02; 35.96 +/- 11.64 vs 22.19 +/- 9.65%, P = 0.002, respectively). COX-2 and HO-1 mRNA were up-regulated after hypoxia. Indomethacin (300 microM) decreased COX-2, HO-1, hypoxia-inducible factor-1alpha and RANTES mRNA and increased cell viability after hypoxia. We conclude that blockade of COX up-regulation can ameliorate endothelial injury, resulting in reduced production of chemokines.

FOXP3-positive regulatory cells inside the allograft and the correlation with rejection

BACKGROUND

Foxp3 is a transcription factor associated with regulatory T cells. Little is known about the role of Foxp3+ regulatory T cells in relation to graft rejection in humans.

METHODS

By using a quantitative polymerase chain reaction assay, we measured the levels of messenger RNA (mRNA) for Foxp3 in 27 samples obtained at allograft nephrectomy for acute nonvascular rejection (ANVR; n = 7), or acute vascular rejection (AVR; n = 15), or loss due to a nonimmune cause (LNIC; n = 5, as control). Granzyme B was also analyzed as a positive control for the host-driven immune response.

RESULTS

Median Foxp3 mRNA levels correlated with the severity of rejection: LNIC 1.000, ANVR 1.429, and AVR 3.904 (P = .022 for LNIC and AVR by the Kruskal-Wallis test). The receiver operating characteristic curve for AVR demonstrated an area under the curve of 0.733 (P = .04; 95% CI, 0.528-0.939). The levels of granzyme B mRNA also showed the same profile but did not reach statistical significance.

CONCLUSIONS

The presence of mRNA for Foxp3 inside the graft suggested specific homing during severe episodes of acute rejection. Its presence may indicate the development of host immunoregulatory responses during the ongoing cytolytic activity. In addition, assessment of Foxp3 mRNA inside the graft may distinguish vascular from nonvascular rejection.

Impact of Therapeutic Changes on Renal Graft Survival With Posttransplant Glomerulonephritis

INTRODUCTION

Posttransplant glomerulonephritis (GN) is the third cause of graft loss after 1 year of transplant follow-up; few approaches have been efficient in reversing this outcome. The aim of this study was to evaluate whether the modification of the immunosuppressive therapy for treating posttransplant GN had an impact on allograft survival.

PATIENTS AND METHODS

Forty-nine patients who underwent renal transplantation and developed posttransplant GN were divided into two groups: group 1, 22 patients with modified immunosuppressive treatment (72.3%, pulse of methylprednisolone; 13.6%, high-dose oral corticosteroid), and group 2, where it was maintained. Additionally, the impact of the concomitant use of drugs that promote the renin-angiotensin-aldosterone system blockade (RAASB) was analyzed in terms of graft survival.

RESULTS

We established the diagnosis of GN at 17.9 months (range, 0.57 to 153.4) after transplantation, when serum creatinine (Cr) was 2.2 mg/dL (range, 0.8 to 12.5) and proteinuria 3.2 g/L (range, 0.2 to 24.2). Graft survivals at 1 and 3 years after diagnosis were 69.2% and 52.9%, respectively. The patients of group 1 showed a lower prevalence of graft loss (27.2% versus 48.1%, P = .40) and better survival at the end of 1 year (73.2% versus 60.4%) and 3 years (62.5% versus 38.0%, P = .26), but the differences were not significant. RAASB showed a positive impact on survival at the end of 3 years in both groups: for group 1, 83.8% with RAASB, 41.4% without RAASB; and for group 2, 75% with RAASB and 14.8% without RAASB (P < .001).

CONCLUSION

Although treatment of posttransplant GN with modification of immunosuppression seemed to improve graft survival in the first 3 years after diagnosis, RAASB improved this effect.

The Effects of Rapamycin in the Progression of Renal Fibrosis

Renal fibrosis is a hallmark of end-stage renal diseases and of chronic allograft nephropathy (CAN). Rapamycin, besides its action through blockade of lymphocyte proliferation, also has antiproliferative, antiviral, and antitumor actions. Its use in clinical in patients with CAN has recently been advocated.

OBJECTIVES

Our goal was to evaluate the effect of rapamycin in an established model of renal fibrosis, unilateral ureteral obstruction.

MATERIALS AND METHODS

C57BL/6 mice were divided into two groups, treated or not with daily doses of rapamycin (0.2 mg/kg) beginning on day-1. The obstruction was performed as day 0. Blood and kidney tissues were collected at 1, 4, 7, and 14 days after the surgery to quantify bone morphogenic protein (BMP)-7 and transforming growth factor (TGF)-beta mRNA by real time PCR.

RESULTS

Daily treatment with rapamycin caused a significant reduction in serum creatinine at day 1 (0.57 +/- 0.03 vs 0.95 +/- 0.15 mg/dL, P = .002) and at day 14 (0.56 +/- 0.04 vs 0.73 +/- 0.07 mg/dL, P = .040). This profile was corroborated by histological morphometric analyses showing less fibrosis at day 14. However, rapamycin surprisingly induced an upregulation of TGF-beta at day 4 (3.05 +/- 0.46 vs 1.85 +/- 0.41, P = .006) and at day 7 (6.33 +/- 0.55 vs 4.97 +/- 0.38, P = .024) with a reduced expression by day 14 (4.03 +/- 1.07 vs 7.89 +/- 0.83, P < .001). Surprisingly, rapamycin also promoted an increment in BMP-7, completely reversing the ratio of TGF-beta to BMP-7, allowing a more protective phenotype.

CONCLUSION

Rapamycin slightly ameliorated the renal dysfunction and, at later time points, induced less fibrosis and less decrease in the TGF-beta to BMP-7 ratio.

The Role of Immunosuppressive Drugs in Aggravating Renal Ischemia and Reperfusion Injury

Renal ischemia followed by reperfusion leads to acute renal failure in both native kidneys and renal allografts. Cyclosporine has known nephrotoxic effects. Thus, cyclosporine therapy subsequent to ischemia/reperfusion (I/R) injury may further exacerbate graft dysfunction. Rapamycin is a newer agent that suppresses the immune system by a different mechanism. In the present study, the effects of Cyclosporine and rapamycin at low and higher concentrations were investigated in an I/R-induced injury model.

METHODS

Cyclosporine (100 mg/kg or 50 mg/kg), rapamycin (3 mg/kg per day or 1.5 mg/kg), or both were administered to mice before being subjected to 45 minutes of ischemia. Blood and kidney samples were collected at 24, 48, and 120 hours after surgery. We quantified acute tubular necrosis and tubular regeneration.

RESULTS

Animals subjected to I/R showed impaired renal function that peaked at 24 hours (2.05 +/- 0.23 mg/dL), decreasing thereafter. Treatment with higher concentrations of cyclosporine or rapamycin caused even more renal dysfunction at 48 hours, which was sustained up to 120 hours after reperfusion (1.53 +/- 0.6 mg/dL), when compared to the low concentrations of cyclosporine or rapamycin (1.08 +/- 0.19 mg/dL; 0.99 +/- 0.14 mg/dL, P < .05, respectively). Cyclosporine delayed tubular regeneration, which was higher in controls at day 5 (67.0% vs 37.6%, P < .05).

CONCLUSIONS

These results demonstrated that cyclosporine or rapamycin might further aggravate ischemically injured organs, negatively affecting posttransplantation recovery in a concentration-dependent fashion.

Severe hyperkalemic type 4 renal tubular acidosis after kidney transplantation: a case report

BACKGROUND

Hyperkalemia after transplantation is a common event, occurring in up to 70% of patients. It is usually asymptomatic but sometimes manifests as muscle weakness or cardiac arrhythmias.

METHODS

Case report.

RESULTS

At 102 days after a second cadaveric kidney transplantation, a 15-year-old boy, was admitted to the emergency room with severe muscle weakness. His examinations showed a serum potassium of 9.8 mEq/L; blood pH 7.1; serum bicarbonate 7.6 mmol/L; and creatinine 2.5 mg/dL. He was initially treated with sodium bicarbonate, calcium gluconate, and furosemide. Subsequent investigation showed hyperchloremic metabolic acidosis, urinary pH <5.5, positive urinary anion gap, reduced transtubular potassium gradient (TTKG, 1.5) and low levels of aldosterone (0.7 ng/mL), suggesting the presence of type 4 renal tubular acidosis (RTA). Other causes of hyperkalemia were excluded in the present case. Serum levels of potassium returned to normal when fludrocortisone was added to the bicarbonate supplementation. This case of severe hyperkalemic secondary to type 4 RTA after kidney transplantation only responded to the combination of alkali and mineralocorticoid therapies.

Beneficial effect of N-acetyl-cysteine on renal injury triggered by ischemia and reperfusion

Reactive oxygen species are critical mediators of the early phase of ischemic (IR) injury. The contribution of antioxidants, such as N-acetyl-cysteine (NAC), in ameliorating the parenchymal lesions, inflammatory parameters, and functional variables in renal IR is still controversial. We studied the effect of NAC administration on renal injury induced by IR. Mice were subjected to renal pedicle occlusion and subsequent reperfusion for 24 or 120 hours. NAC was administered prior to surgery at two concentrations (40 or 300 mg/kg, i.p.). Renal function and acute tubular necrosis were assessed, as well as immune phenotyping of infiltrating cells, by flow cytometry. At 40 mg/dL of NAC, we did not observe any significant improvement in renal function (1.85 +/- 0.43 md/dL, P = .367) or tissue architecture (% of ATN: 2.51 +/- 0.27 mm, P = .852) compared to the controls (1.87 +/- 0.43 mg/dL and 3.12 +/- 0.34 mm, respectively). However, animals that received 300 mg/dL of NAC showed lower serum creatinine values (24 hours: 1.25 +/- 0.54 mg/dL) compared to controls (P = .009) and less extensive acute tubular necrosis (1.54 +/- 0.12 vs, P < .05). Treatment with 300 mg/dL of NAC decreased renal dendritic cell infiltration. The protective effect of NAC was better observed at high concentrations and early times.

Dual response of animals with chronic cyclosporine nephrotoxicity to an acute ischemic injury

Normal kidneys regenerate after acute injury with little development of chronic fibrosis. However, the long-term effects of an acute injury in kidneys with established chronic toxicity induced by cyclosporine (CsA) are not entirely clear. To study the consequences of an ischemia and reperfusion (IR) injury in long-term CsA-treated rats, male Wistar rats (250-300 g) were treated daily with CsA (10 mg/kg) or vehicle (olive oil 1 mL/kg) for 28 days. On day 21, ischemia was performed by clamping the renal vessel for 1 hour. Blood samples were collected on days 0 and 21 (before IR) as well as days 22 and 28. On day 28, the kidneys were collected to examine the mRNA expression of MCP-1 by real-time PCR. For renal function, serum creatinine levels were measured. Twenty-four hours after reperfusion, long-term CsA-treated animals showed better renal function compared with the control group, as demonstrated by serum creatinine levels: 2.2 +/- 0.13 mg/dL vs 2.9 +/- 0.18 mg/dL, respectively (P < .05). However, 1 week after IR, the renal function was worse among the long-term CsA-treated group than the controls: 1.16 +/- 0.08 mg/dL vs 0.8 +/- 0.09 mg/dL, respectively (P < .05). Interestingly, CsA treatment was associated with lower MCP-1 mRNA expression than that in the control group: mean MCP-1 mRNA expression 0.58 +/- 0.13 vs 1.02 +/- 0.12, respectively (P < .05). In conclusion, animals with chronic CsA nephrotoxicity were protected from an acute renal injury, possibly through decreased chemokine production, although at later time points, renal function was clearly impaired, probably by the acceleration of vasculopathy caused by nephrotoxicity.

Determination of renal function in long-term heart transplant patients by measurement of urinary retinol-binding protein levels

Significant improvements have been noted in heart transplantation with the advent of cyclosporine. However, cyclosporine use is associated with significant side effects, such as chronic renal failure. We were interested in evaluating the incidence of long-term renal dysfunction in heart transplant recipients. Fifty-three heart transplant recipients were enrolled in the study. Forty-three patients completed the entire evaluation and follow-up. Glomerular (serum creatinine, creatinine clearance measured, and creatinine clearance calculated) and tubular functions (urinary retinol-binding protein, uRBP) were re-analyzed after 18 months. At the enrollment time, the prevalence of renal failure ranged from 37.7 to 54% according to criteria used to define it (serum creatinine > or = 1.5 mg/dL and creatinine clearance <60 mL/min). Mean serum creatinine was 1.61 +/- 1.31 mg/dL (range 0.7 to 9.8 mg/dL) and calculated and measured creatinine clearances were 67.7 +/- 25.9 and 61.18 +/- 25.04 mL min-1 (1.73 m(2))-1, respectively. Sixteen of the 43 patients who completed the follow-up (37.2%) had tubular dysfunction detected by increased levels of uRBP (median 1.06, 0.412-6.396 mg/dL). Eleven of the 16 patients (68.7%) with elevated uRBP had poorer renal function after 18 months of follow-up, compared with only eight of the 27 patients (29.6%) with normal uRBP (RR = 3.47, P = 0.0095). Interestingly, cyclosporine trough levels were not different between patients with or without tubular and glomerular dysfunction. Renal function impairment is common after heart transplantation. Tubular dysfunction, assessed by uRBP, correlates with a worsening of glomerular filtration and can be a useful tool for early detection of renal dysfunction.

The role of heme oxygenase 1 in rapamycin-induced renal dysfunction after ischemia and reperfusion injury

Ischemia and reperfusion injury (IRI) is the main etiology of acute renal failure in native and transplanted kidneys. In the transplantation field, immunosuppressive drugs may play an additional role in acute graft dysfunction. Rapamycin may impair renal regeneration post IRI. Heme oxygenase 1 (HO-1) is a protective gene with anti-inflammatory and anti-apoptotic actions. We investigated whether HO-1 played a role in rapamycin-induced renal dysfunction in an established model of IRI. Rapamycin (3 mg/kg) was administered to mice before being subjected to 45 min of ischemia. Animals subjected to IRI presented with impaired renal function that peaked at 24 h (2.05+/-0.23 mg/dl), decreasing thereafter. Treatment with rapamycin caused even more renal dysfunctions (2.30+/-0.33 mg/dl), sustained up to 120 h after reperfusion (1.54+/-0.4 mg/dl), when compared to the control (0.63+/-0.09 mg/dl, P<0.05). Rapamycin delayed tubular regeneration that was normally higher in the control group at day 5 (68.53+/-2.30 vs 43.63+/-3.11%, P<0.05). HO-1 was markedly upregulated after IRI and its expression was even enhanced by rapamycin (1.32-fold). However, prior induction of HO-1 by cobalt protoporphyrin improved the renal dysfunction imposed by rapamycin, mostly at later time points. These results demonstrated that rapamycin used in ischemic-injured organs could also negatively affect post-transplantation recovery. Modulation of HO-1 expression may represent a feasible approach to limit rapamycin acute toxicity.

Effect of Thymoglobulin in Graft Survival and Function 1 Year After Kidney Transplantation Using Deceased Donors

This study evaluated 1-year graft function and survival among kidney transplantations from deceased donors using thymoglobulin (Thymo) as an induction strategy.

PATIENTS AND METHODS

Fifty-seven percent of patients were men and overall mean age was 42 +/- 15 years. Cold ischemia time was 20.1 +/- 4.8 hours. The primary outcome was defined as survival not censored for death after 1 year. The secondary outcome was defined as a comparison of function and survival among patients who received more or less then six doses of Thymo.

RESULTS

Four patients experienced acute rejection episodes and the other three died during follow-up. One-year graft survival was 91% with a mean serum creatinine of 1.28 +/- 0.43 mg/dL. Cytomegalovirus infection occurred in 56%. Forty-two (64%) patients displayed acute tubular necrosis of mean duration of 6.89 +/- 7.48 days. Patients who received lower doses showed better serum creatinine values 3 months (1.45 vs 1.86 mg/dL, P = .013) and 12 months (1.05 vs 1.50 mg/dL, P = .04). The difference was probably due to acute tubular necrosis that produced a RR of 1.7 (P = .02; CI 1.04-2.97) when compared with patients with Scr values above 1.30 mg/dL. When censored for death, graft survival was not different between the two groups (< or =6 doses 93% vs >6 doses 97%, P = .43).

CONCLUSION

Immunologic induction with Thymo produced excellent graft survival after 1 year with preservation of graft function. Delayed graft function was the most important determinant of graft function after 1 year.

Expression of cyclooxygenases during renal allograft rejection

The aim of this work was to determine the expression of cyclooxygenases (COX-1 and COX-2) during acute human renal allograft rejection. RT-PCR and immunohistochemistry were performed. The COX-2 mRNA was more abundant than COX-1 mRNA in the group with acute rejection (P <.001). The locations of COX-1 and COX-2 protein were consistent with the literature. Expression of COX-2 immunoreactive protein was higher in interstitial cells in the group with acute rejection than in the control group (P =.04). COX-2 protein was more abundant than COX-1 protein in the group with acute rejection, including podocytes (P <.001), proximal tubular cells (P <.001), collecting duct cells (P =.003), and interstitial cells (P <.001). In conclusion, COX-2 which is up-regulated during acute human renal allograft rejection, may play a role in renal inflammation.

Serial beta-2 microglobulin measurement as an auxilliary method in the early diagnosis of cytomegalovirus infection in renal transplant patients

Infection by cytomegalovirus is one of the most important causes of morbidity and mortality after renal transplant. During episodes of acute rejection serum levels of beta-2 microglobulin (B2M) are elevated due to decreased excretion and/or increased production from T-cell proliferation. Sequential measurement of B2M in the first months after transplantation may detect patients at increased risk of rejection. This study assesses the usefulness of serum B2M for early detection of patients with increased risk of cytomegalovirus disease. Among 16 of 18 cases of CMV infection, there was an increase in serum B2M levels before CMV diagnosis. In all cases, B2M serum levels increased at an average of 10.8 days before the symptoms or the positive antigenemia. From a mean baseline B2M value of 5.0 mg/L, the mean value at the time of diagnosis was 7.7 mg/L before any clinical or laboratory evidence of CMV infection. These findings suggest that B2M serum levels can be used as a marker for early diagnosis of cytomegalovirus infection.

Sequential cytomegalovirus antigenemia monitoring in kidney transplant patients treated with antilymphocyte antibodies

BACKGROUND

Antilymphocyte antibodies (ALA) use is related to disseminated cytomegalovirus (CMV) disease after kidney transplantation. Strict surveillance of CMV infection, preemptive antiviral treatment or concomitant ganciclovir and ALA use are proposed as an attempt to prevent related clinical complications. Our objective was to describe the pattern of CMV infection, based on sequential antigenemia detection, after ALA treatment.

PATIENTS AND METHODS

Thirty renal transplant patients were prospectively screened for CMV infection after ALA treatment. CMV antigenemia (pp65 antigen detection) was monitored twice a week in the first month and weekly until 60 days after the beginning of ALA therapy. Any positive value of antigenemia was considered CMV infection.

RESULTS

Twenty-eight (93.3%) patients were CMV positive (IgG) before transplantation. The mean duration of ALA treatment was 12.1+/-2.4 days. Positive antigenemia was detected in 24 (80%) patients, a mean of 52.5+/-15 days after transplant and 44.7+/-14 days after the beginning of ALA treatment. The median antigenemia count was 7 positive cells/300,000 neutrophils (range: 1-227). Antigenemia preceded clinical symptoms by 5.8 days (0-28 days). Eighteen (75%) of 24 positive patients received ganciclovir treatment: 8 patients (26.7%) for viral syndrome, 2 patients (33.3%) for invasive disease, and 8 patients (26.7%) as part of preemptive therapy, asymptomatic with high antigenemia values. Six pp65-positive patients with low counts were followed up until a negative result and remained asymptomatic without any specific treatment.

CONCLUSION

CMV infection was frequent after ALA treatment in this group and generally occurred late after completion of treatment. Antigenemia was a reliable tool to guide preemptive treatment in these patients, and such strategy is an alternative option compared to the prophylactic use of ganciclovir with ALA treatment.

Monitoring Anti-HLA Class I IgG antibodies in renal transplant recipients

Anti-HLA class I IgG antibodies play an important role in hyperacute rejection but the significance of its de novo appearance or increase in levels during the posttransplant period remains controversial. The purpose of this study was to determine the correlation between the anti-HLA class I IgG antibodies and posttransplant events during the first 4 months after renal transplantation. From 200 renal allograft recipients, 549 serum samples were retrospectively evaluated. Patients who experienced graft dysfunction confirmed by biopsy had three serum samples tested: before, during (within 24 hours), and after the event. The presence of anti-HLA antibodies was observed in recipients with chronic allograft nephropathy (60%); acute rejection (clinical criteria without biopsy 57.1%); rejection types IIA (7.1%), IIB (40%), and III (50%); borderline changes (42.8%); acute tubular necrosis (34.4%); infarction (25%); and no rejection (12.5%). We observed a high incidence of anti-HLA class I IgG antibodies during acute tubular necrosis, borderline changes, acute rejection types IIB and III, and chronic allograft nephropathy.

Expression of CD40 ligand, interferon-gamma and Fas ligand genes in endomyocardial biopsies of human cardiac allografts: correlation with acute rejection

The purpose of the present study was to investigate the expression (mRNA) of CD40 ligand (CD40L), interferon-gamma (IFN-gamma) and Fas ligand (FasL) genes in human cardiac allografts in relation to the occurrence of acute cardiac allograft rejection as well as its possible value in predicting acute rejection. The mRNA levels were determined by a semiquantitative reverse transcriptase-polymerase chain reaction method in 39 samples of endomyocardial biopsies obtained from 10 adult cardiac transplant recipients within the first six months after transplantation. Biopsies with ongoing acute rejection showed significantly higher CD40L, IFN-gamma and FasL mRNA expression than biopsies without rejection. The median values of mRNA expression in biopsies with and without rejection were 0.116 and zero for CD40L (P<0.003), 0.080 and zero for IFN-gamma (P<0.0009), and 0.156 and zero for FasL (P<0.002), respectively. In addition, the levels of IFN-gamma mRNA were significantly increased 7 to 15 days before the appearance of histological evidence of rejection (median of 0.086 in pre-rejection biopsies), i.e., they presented a predictive value. This study provides further evidence of heightened expression of immune activation genes during rejection and shows that some of these markers may present predictive value for the occurrence of acute rejection.

Early detection of heart transplant patients with increased risk of ciclosporin nephrotoxicity

Chronic nephrotoxic effects from ciclosporin are a common clinical complication after heart transplantation and frequently lead to progressive renal failure. There is no laboratory test to predict development of chronic renal failure in heart transplant patients. We analysed urinary retinol-binding protein (uRBP) concentration, to assess proximal tubular dysfunction, in 36 clinically stable heart transplant patients. We detected a subgroup of 13 patients who had high concentrations of uRBP, good renal function, and a high risk of developing progressive renal failure compared with patients with normal uRBP (relative risk 3.87, p=0.003).