P. Szyber

The influence of calcineurin inhibitors on mycophenolic acid pharmacokinetics

Despite the fact that concentrations of mycophenolic acid (MPA) are not routinely measured, accumulating data suggest the usefulness of this monitoring to optimize therapy. The aim of this study was to assess the influence of CsA and tacrolimus on MPA pharmacokinetics. Concentrations of MPA were measured using HPLC. An assay was performed before dose (the C(0)), as well as at 40 minutes and 1, 2, 4, 6, 8, 10, 12 hours after administration of mycophenolate mofetil (MMF). MPA profiles were assessed in 51 patients receiving tacrolimus at a dose of 1.0 g/d and prednisone as well as in 97 patients receiving CsA (2.0 g/d) and prednisone. Significant correlations of MPA levels with serum albumin and GFR were observed in both groups. Women presented with higher levels of MPA than men. C(0) MPA level among the tacrolimus group were significantly higher than those in CsA group: 3.18 +/- 2.21 microg/mL versus 1.68 +/- 1.03 microg/mL (P </=.001). The level of MPA AUC((0-12)) in the tacrolimus group was nonsignificantly higher than that in the CsA group. There was no second peak of MPA level in a group of patients receiving CsA. We developed a limited sampling strategy to estimate MPA AUC((0-12)) in both tacrolimus and CsA groups. We observed a correlation between C(0) MPA and C(0) CsA (r =.35; P </=.001) as well as, between tacrolimus dose and MPA C(40) and MPA C(max) (r =.24; P </=.05; r =.27; P </= 0.05, respectively). No relationship between MPA pharmacokinetics and tacrolimus blood concentrations was noticed. Tacrolimus and CsA both affect the pharmacokinetics of MPA; high MPA concentrations in patients treated with tacrolimus justify MMF dose reduction in this group. Alterations of CsA concentrations must be used to guide MMF dose adjustments.

Long-term Follow-up of Non-HLA and Anti-HLA Antibodies: Incidence and Importance in Renal Transplantation

BACKGROUND Detection of antibody-mediated injury is becoming increasingly important in post-transplant patient care. The role of donor-specific anti-human leukocyte antigen (HLA) antibodies in kidney transplant damage is known, whereas the significance of non-HLA antibodies remains an unresolved concern. The aim of the study was to determine the presence and influence on renal function of non-HLA and anti-HLA antibodies in stable patients at 5 years after kidney transplantation. METHODS We evaluated the antibodies in 35 consecutive patients with stable renal function at 5 years after transplantation. RESULTS Pretransplant screening for donor-specific antibodies by CDC cross-matches was negative in all patients. Anti-endothelial cell antibodies (AECA), anti-angiotensin II type 1 receptor antibodies (anti-AT1R), and anti-endothelin receptor antibodies (anti-ETAR) were assayed as non-HLA antibodies. Non-HLA antibodies were observed in 12 (34%) patients, including AECA (n = 5; 14%), anti- AT1R (n = 6; 17%), anti-ETAR (n = 4; 11%), and both anti-AT1R and anti-ETAR (n = 3). Among 13 (37%) patients with anti-HLA antibodies, 7 also had both non-HLA antibodies: AECA (n = 1), anti-AT1R (n = 3), and anti-ETAR (n = 3). The antibody-negative group (n = 13) showed significantly better renal function than the antibody-positive group (non-HLA and/or anti-HLA; n = 22). Biopsy-proven acute rejection had occurred in 2 of 13 (15%) antibody-negative versus 8 of 22 (36%) antibody-positive patients. These preliminary data revealed an high prevalence of autoantibody and alloantibody production among stable patients at 5 years after kidney transplantation. CONCLUSION Simultaneous production of these antibodies and their association with reduced renal function suggests that active humoral immune responses are poorly controlled by immunosuppression.

Mycophenolate mofetil severely depresses antibody response to CMV infection in early posttransplant period

Estimation of anti-CMV-IgG and anti-CMV-IgM is considered a relatively inexpensive screening tool of CMV status. The aim of study was to estimate how the immunosuppressive protocol influence serum anti-CMV IgG and IgM concentration in renal graft recipients and to estimate the adequacy of anti-CMV-IgG concentration and anti-CMV-IgM index as screening parameters of active CMV disease in patients receiving different immunosuppression. The study group consisted of 33 patients with clinical signs of CMV disease who received one of three types of immunosuppression: (1) azathioprine (Aza) + cyclosporine (CyA) + prednisone (Pr), 20 patients; (2) mycophenolate mofetil (MMF) + CyA + Pr, eight patients; tacrolimus (Tac) + MMF, five patients. Patients were enrolled when the pp65-antigen (pp65) of PBL was positive within 1 to 5 months after transplant (75 patients tested). The IgM-i in the Aza + CyA + Pr group was higher than in MMF + CyA + Pr group (2.73 + 1.8 vs 1.08 +/- 1.07, P =.021). The IgM-i in the Aza + CyA + Pr group was higher than in Tac + MMF (2.73 +/- 1.8 vs 0.78 +/- 0.69; P =.014). There was no difference in IgM-i between MMF + CyA + Pr and Tac + MMF. There was no difference in relative increase of IgG-c among all groups but there was a difference in relative increase of IgM-i between Aza + CyA + Pr and MMF + CyA + Pr groups (6.7 +/- 9.4 vs 2.3 +/- 5.9; P =.007) and between Aza + CyA + Pr and MMF + Tac groups (6.7 +/- 9.4 vs 0.6 +/- 0.54; P =.003). Immunosuppressive protocols including MMF exert an inhibitory influence on B-cell response and synthesis of anti-CMV-IgM. It makes the anti-CMV-IgM index an inadequate rough screening diagnostic parameter of active CMV disease.

Non-HLA antibodies: angiotensin II type 1 receptor (anti-AT1R) and endothelin-1 type A receptor (anti-ETAR) are associated with renal allograft injury and graft loss.

INTRODUCTION Non-HLA antibodies specific for angiotensin II type 1 receptor (anti-AT1R) and endothelin-1 type A receptor (anti-ETAR) of vascular cells activate signaling pathways leading to cell proliferation and vascular injury. The aim of this study was to evaluate the impact of non-HLA antibodies on kidney allograft morphology and function in patients who underwent a kidney biopsy due to renal function impairment. PATIENTS AND METHODS The study included 65 consecutive renal transplant patients who were evaluated for the presence of non-HLA and anti-HLA antibodies at the time of transplant biopsy. Results of pre-transplant CDC cross-match were negative. A kidney allograft biopsy was performed between 6 days and 13 years (42 ± 49 months) after transplantation, and the diagnosis was made on the basis of the Banff criteria. The level >9 U/L of anti-AT1R and anti-ETAR antibodies was considered high. RESULTS A high level of non-HLA antibodies (anti-AT1R and/or anti-ETAR) was found in 7 (10.7%) of 65 patients at the time of biopsy. Graft loss in the non-HLA-positive patients was significantly higher (71% in non-HLA-positive cases after 7.8 ± 2.6 months vs 11% after 6 months in non-HLA-negative cases [P = .00099]). In these non-HLA-positive patients, the mean anti-AT1R level was 15.3 ± 9.4 U/L and the mean anti-ETAR level was 13.8 ± 8.6 U/L. In only 2 of these patients were anti-HLA antibodies additionally detected: anti-class I in 1 and anti-class II in both patients. The mean serum creatinine level was 2.34 ± 0.6 mg/dL at the time of biopsy. Results of an early biopsy revealed acute vascular rejection (Banff grade IIB). Chronic allograft injury was found (grading cg1-3, cv1-2, ci1-2, ct1-2) in the remaining 6 patients. C4d was present in 3 of 7 patients. CONCLUSIONS High levels of anti-AT1R and/or anti-ETAR antibodies were associated with morphological and functional allograft injury and graft loss in these study patients. Non-HLA antibodies can be helpful in assessing the risk of graft failure.

The increased risk of post-transplant diabetes mellitus in peritoneal dialysis-treated kidney allograft recipients

BACKGROUND Post-transplant diabetes mellitus (PTDM) is a common metabolic complication in kidney allograft recipients, significantly contributing to the elevated cardiovascular morbidity after renal transplantation and increased risk of chronic transplant dysfunction. The aim of the present investigation was to evaluate the factors influencing PTDM development. Under particular consideration were the elements, existing before the transplantation, especially the modality of dialysis treatment significance, i.e. haemodialysis (HD) versus peritoneal dialysis (PD). METHODS Three hundred and seventy-seven consecutive outpatients who underwent renal transplantation (RTx) in our institution between January 2003 and December 2005 were analysed. PTDM was diagnosed according to the current American Diabetic Association/World Health Organization criteria. Statistical inference was conducted by means of univariate methods (one factor versus PTDM) and multivariate methods in frames of generalized linear model. RESULTS In the study group, 72 patients (23.4%) developed PTDM after RTx (55 HD and 17 PD patients). PTDM incidence at 3, 6 and 12 months was 15.9%, 22.1% and 23.4%, respectively. The mean interval from transplantation to the onset of PTDM was 3.08 ± 2.73 months. In univariate analysis, the factors associated with the elevated risk of PTDM appearance were older recipient age, positive family history of diabetes, hypertensive nephropathy as end-stage renal disease cause, higher body mass index at transplantation, treatment by PD, and the graft from an older donor. In multivariate verification, statistical significance remained: older recipient age (P < 0.001), positive family history of diabetes (P = 0.002), and treatment by PD (P = 0.007). CONCLUSIONS Treatment by PD appears to be a possible novel factor, not yet reported, which may increase the risk of PTDM development.

Extracorporeal photopheresis as an antirejection prophylaxis in kidney transplant recipients: preliminary results.

Extracorporeal photopheresis (ECP) is considered a promising immunomodulatory therapy of acute allograft rejection in organ transplantation and graft-versus-host disease. Our aim was to investigate the biological responses of 10 patients who underwent kidney transplantation with ECP as prophylactic treatment. They received conventional immunosuppressive therapy plus ECP immediately after transplantation: 12 to 16 applications over the course of 2.5 months. ECP procedures were performed using an automated system for leukocyte separation and photoactivation with methoxsalen. All recipients were followed by estimated glomerular filtration rate (eGFR) and peripheral T, B, natural killer, T-regulatory (Treg) and dendritic cells (DC) counts and phenotypes. An acute rejection episode appeared in one control group recipient. The ECP group showed a positive trend to an higher GFR at months 3 (53±11 vs 47.1±9; P=.17) and 6 (67.5±10 vs 53.6±3; P=.03, Wilcoxon test). An increased percentage of Treg (CD3+ CD4+ CD25+) among the total CD3 cell count (4.9%±1% to 9.4%±15%) as well as inducible Treg (CD3+ CD8+ CD28-) was observed among CD3 cells (3.3%±3% to 11.8%±8%, P=.025) within 3 months of ECP treatment. A significant difference in the percentage of Treg was noted at month 3 (completed ECP) between the ECP and the control groups (9.4%±15% vs 3%±1%; P=.01). Addition of ECP to standard immunosuppression was associated with a significantly higher GFR at 6 months and with a significant increase in natural Treg among CD3 cells.

Gingival overgrowth in kidney transplant recipients treated with cyclosporine and its relationship with chronic graft nephropathy

Our previous study of a group of renal transplant recipients treated with CsA showed a significantly faster development of chronic graft failure among patients with gingival hyperplasia (GH) compared to unaffected patients. The aim of the present research was to establish the impact of CsA dose and blood levels on the incidence of chronic graft nephropathy and gingival overgrowth as well as to assess risk factors for chronic graft nephropathy. The study included 64 renal graft recipients (32 patients with GH and 32 without GH) transplanted between 1989 and 1994. There were no significant differences between the pretransplant demographic and clinical data of the patients with and without GH. Patients with GH received a significantly higher total yearly dosages of CsA compared those without GH (P <.03). Serum creatinine in the first year posttransplant in patients with GH was 1.9 mg/dL versus 1.6 mg/dL in those without GH. During 9 to 14 years follow-up, end-stage renal failure due to chronic nephropathy occurred in 18 patients (56%) with GH and eight patients (25%) without GH. Ten-year renal graft survival was 35% in GH patients and 69% in patients without GH. Ten-year patient survival was 69% in the GH group and 91% in the group without GH. CsA dosage was a risk factor for GH and for graft loss, which implies a role of CsA toxic effects on the pathological mechanisms of GH and of chronic allograft nephropathy.

Cytokine gene expression in kidney allograft donor biopsies after cold ischemia and reperfusion using in situ RT-PCR analysis.

It was previously reported that ischemia-reperfusion injury initiates an inflammatory response and may significantly affect the transplanted organ function. The aim of this study was to assess changes of intragraft cytokine mRNA expression in kidneys after cold ischemia (CI) and following reperfusion. We examined mRNA of a product of activated T lymphocytes (IFN-gamma) and a monocyte product (IL-6). Eleven kidneys were transplanted after CI time ranging from 16 to 39 hours. Renal needle core biopsies were obtained from donors after cold ischemia and approximately after 20 minutes of reperfusion. Tubular and glomerular expression of IFN-gamma and IL-6 mRNA were assessed using semiquantitative evaluation of the RT-PCR in situ. After reperfusion an intense increase of IL-6 mRNA expression was observed in four specimens, a slight increase was noticed in five specimens, and a very slight decrease in two specimens. Changes in IL-6 mRNA expression were limited only to tubules. In contrast, the glomerular and tubular mRNA expression of IFN-gamma and glomerular of IL-6 remained stable. Mean CI time for patients with an intense increase was higher than for patients with a slight increase and with the decrease of IL-6 mRNA expression (32.0 +/- 6.8 vs 25.2 +/- 7.3 and 26.0 +/- 5.7 hours). Our results suggest that early inflammatory changes at the time of implantation of renal allografts depends mainly on monocyte/macrophage-associated products. The observed intensity of their expression in tubules was connected to longer CI time.

Influence of hypercholesterolemia and acute graft rejection on chronic nephropathy development in renal transplant recipients

Graft endothelial lesions resulting from acute rejection may be sustained by concomitant hypercholesterolemia, thus increasing the risk of chronic graft failure. The present study was undertaken to examine the influence of hypercholesterolemia and acute graft rejection (AGR) episodes on graft function and graft loss due to chronic nephropathy. A cohort of 336 patients transplanted between 1993 and 2000 having graft function at 12 months after transplantation were examined. Immunosuppressive therapy consisted of CsA, azathioprine, and corticosteroids in 90% with 10% of patients receiving mycophenolate mofetil in place of azathioprine. During the first year after transplantation, AGR occurred in 134 (39.8%) and hypercholesterolemia (6.2 mmol/L) in 132 (39.2%) of patients. The population was divided into four groups according to AGR occurrence and cholesterol concentrations during the first year after transplantation for analysis of serum creatinine concentrations and graft loss at 5 years of follow-up. Patients with AGR irrespective of cholesterol levels displayed significantly higher creatinine concentrations. Graft loss in these patients increased over twofold compared to the remaining groups. Patients without hypercholesterolemia and AGR showed normal creatinine concentrations and low graft loss rates during 5 years of follow-up.

Iatrogenic pseudoaneurysm of the popliteal artery following corrective tibial osteotomy.

Due to its anatomical location the popliteal artery is exposed to injury during surgical procedures in the region of the knee joint, in particular during high-level corrective osteotomies of the proximal tibial epiphysis. Nevertheless, posttraumatic (iatrogenic) pseudoaneurysm constitutes a very rare complication of the procedure. Only few reports of such complication have been published and they were usually connected with lateral tibial osteotomy - the accidents after medial osteotomy are seldom. The complication we report was observed in a 52-year-old female patient after corrective osteotomy of the medial portion of the proximal tibial epiphysis. The complication was diagnosed 7 days after surgery on US-examination and subsequently confirmed by emergently performed angio-CT. The patient was referred for urgent reconstructive surgery. No significant complications were observed, neither postoperatively nor during follow-up visits.