CsA-treated Renal Transplant Recipients Research Articles

Relationship between hemorheology and endothelial dysfunction in renal transplant patients receiving calcineurin inhibitors

Calcineurin inhibitors, mainly cyclosporin A (CsA), are associated with endothelial dysfunction in renal transplant recipients (RTRs). Hemorheological disturbances including decreased erythrocyte deformability (ED), increased plasma viscosity and erythrocyte aggregation (EA) have also been reported in CsA-treated RTRs. The aim of this study was to investigate the relationship between hemorheological factors and endothelial dysfunction in CsA- and tacrolimus (Tc)-treated RTRs. Thirty-one RTRs and 16 healthy subjects were recruited. The RTR group received either CsA (n = 16) or Tc (n = 15). Endothelial function was evaluated by flow-mediated dilation (FMD) of the brachial artery. ED and EA were measured with laser-assisted optical rotational cell analyzer, and plasma viscosity by a cone-plate viscometer. FMD of the CsA group was significantly lower than that of controls (6.3% ± 5.1% vs. 11.9% ± 5.6%, p = 0.024), whereas, there was no significant difference between the Tc group (8.8% ± 5.4%) and controls. At shear stresses ranging between 0.95 and 30 Pa, EDs of the CsA group were significantly lower compared with controls. In the Tc group, the decrease in ED was significant at shear stresses ranging between 0.53 and 5.33 Pa. ED indices did not correlate with FMD in any of the groups. The degree of endothelial dysfunction and reduction in ED were more remarkable in patients on CsA therapy. Hemorheological factors were not likely to be associated with endothelial dysfunction in RTRs.

Transforming growth factor‐β1 gene expression and cyclosporine A‐induced gingival overgrowth: a pilot study

The relationship between gingival overgrowth (GO) induced by cyclosporine A (CsA) and transforming growth factor-beta1 (TGF-beta1) remains unclear. The aims of the present study were to evaluate TGF-beta1 gene expression under different immunosuppressive treatments and its association with TGF-beta1 gene functional polymorphism and GO in renal transplant recipients. The study included 98 CsA-treated renal transplant recipients (with and without GO) and 44 tacrolimus-treated transplant patients (without GO). TGF-beta1 mRNA expression was measured using a real-time quantitative polymerase chain reaction assay. The levels were correlated with TGF-beta1 gene polymorphisms at codons 10 and 25, with different immunosuppressive treatment and GO. The level of TGF-beta1 gene expression was insignificantly lower in the CsA-treated group compared with the tacrolimus group, and significantly lower in the group with GO compared with patients without GO. In tacrolimus- and CsA-treated patients, but not in patients with GO, the level of TGF-beta1 gene expression was associated with functional phenotypes of TGF-beta1. The incidence, degree and extent of GO were higher in recipients with lower TGF-beta1 gene expression. Lower level TGF-beta1 gene expression, not functional polymorphism, in patients treated with CsA may be considered to be a risk factor for GO.

Effects of antioxidant supplementation on blood cyclosporin A and glomerular filtration rate in renal transplant recipients

Transplant recipients have elevated oxidative stress, which has prompted suggestions that supplementary antioxidants may be beneficial. However, only a small number of clinical trials have investigated antioxidant supplementation in transplant recipients, with very few data on their effects on patients' immunosuppressive therapy. A randomized placebo-controlled single-blind crossover trial was conducted in 10 renal transplant recipients (RTRs) taking cyclosporin A (CsA) as part of their immunosuppressive therapy. Each phase of the trial lasted 6 months, with a 6 month wash-out period in between. During one of the phases, patients consumed a tablet twice per day which delivered 400 IU/day of vitamin E, 500 mg/day of vitamin C and 6 mg/day of beta-carotene. During antioxidant supplementation, there was no change in CsA dose. Antioxidant supplementation resulted in a significant decrease (P<0.05) in blood trough CsA by 24% (mean+/-SD, pre- 127.3+/-38.9, post- 97.2+/-30.7 microg/ml) compared with no change while taking the placebo (pre- 132.2+/-50.6, post- 138.6+/-56.0 microg/ml). The glomerular filtration rate was significantly (P<0.05) improved by 12% during antioxidant supplementation (pre- 66.9+/-20.7, post- 75.0+/-20.1 ml/min/1.72 m2), with no change during the placebo phase (pre- 66.8+/-11.8, post- 66.7+/-16.1 ml/min/1.72 m2). There were no significant differences (P>0.05) in markers of oxidative stress (malondialdehyde, susceptibility of plasma to oxidation) or plasma antioxidant enzymes. In CsA-treated RTRs, antioxidant supplementation decreased blood CsA, which may affect adequacy of immunosuppression.

Effect of Cyclosporin A on Apoptosis and Expression of p53 and bcl‐2 Proteins in the Gingiva of Renal Transplant Patients

Gingival overgrowth (GO) is a common side effect of cyclosporin A (CsA) therapy, but the exact mechanism for this is unknown. Apoptosis plays an important role in the maintenance of tissue homeostasis and mediators of this process may be involved in the pathogenesis of drug-induced GO. This study compared p53 expression, bcl-2 expression, and apoptosis in gingival samples from CsA-treated renal transplant recipients to findings in controls with gingivitis. Twenty-two kidney recipients with CsA-induced GO and 15 systemically healthy subjects with gingivitis were included in the study. The 15 systemically and periodontally healthy volunteer control group were immunohistochemically analyzed for grades of p53 and bcl-2 expression, and were processed using terminal TdT-mediated dUTP-biotin nick-end labeling (TUNEL) technique to identify and grade levels of apoptosis. There were no differences between the CsA group and the control group with respect to grades of p53 and bcl-2 expression (P >0.05 for both). However, the CsA group showed a lower apoptosis grade than the control group (P <0.05). None of the clinical parameters was significantly correlated with any of the immunohistochemical findings for p53 or bcl-2 (P >0.05 for all). Similarly, grade of apoptosis was not correlated with any of the clinical parameters (P >0.05). There was a significant positive correlation between serum CsA level and level of bcl-2 expression, but serum CsA was not significantly correlated with level of apoptosis or level of p53 expression. The results indicate that the pathogenesis of CsA-induced GO might involve inhibition of apoptosis, and overexpression of bcl-2 in the setting of high serum CsA.

Cyclosporin exposure correlates with 1 year graft function and histological damage in renal transplanted patients.

Cyclosporin (CsA) level obtained 2 h after the morning dose (C(2)) has been shown to accurately predict total CsA exposure and acute rejection (AR) risk, whereas conventional trough levels (C(0)) do not. The impact of C(2) monitoring on long-term kidney graft function, independent from AR risk, is still unclear, however, and it was assessed in the present study. We enrolled 39 CsA-treated renal transplant recipients and used 1 year graft function and histological structure as surrogate markers of graft outcome. CsA dose was adjusted according to C(2) levels. In the first 7 days after grafting, 40-51% of patients failed to reach target C(2) levels; nevertheless, at 1 year the incidence of AR was only 2.5% and graft and patient survival was 100%. The decrease of serum creatinine (12-6 months) was associated with significantly higher C(2) levels over time (P = 0.0003) and lower intrapatient variability of CsA relative absorption (CV) (P = 0.0006). One year graft biopsy showed chronic tubulointerstitial lesions in 54.5% of patients. Both C(2) mean levels and the percentage CV independently predicted the severity of chronic histological lesions (R = 0.69, P<0.0001). Higher C(2) levels, within the proposed target range values, seem to be associated with better renal function and structure.

High prevalence of Chlamydia pneumoniae infection in cyclosporin A-induced post-transplant gingival overgrowth tissue and evidence for the possibility of persistent infection despite short-term treatment with azithromycin.

Cyclosporin A (CsA) induces gingival overgrowth (GO) in up to a quarter of CsA-treated renal transplant recipients. A short-term therapy with azithromycin effectively reduces GO, indicating a possible involvement of microorganisms in the pathogenesis of CsA-induced GO. We aimed to determine if there could be any relationship between infection with Chlamydia pneumoniae and GO pathogenesis. In addition, we determined the long-term persistence rate of C. pneumoniae infection in residual GO tissue when azithromycin treatment failed to eliminate GO. Chlamydia pneumoniae IgG and IgM antibody titres were measured by microimmunofluorescence technique in sera of kidney recipients with (n = 11) and without (n = 89) GO. GOs were rated and gingivectomies were performed before treatment with 500 mg of azithromycin for 3 days and at months 6 and 12 post-treatment when C. pneumoniae titres were re-evaluated. Nested polymerase chain reaction was performed to identify C. pneumoniae-specific DNA in GO tissues. Results of C. pneumoniae antibody titres from patients with GO were compared with pair-matched controls without GO. Chlamydia pneumoniae IgM titres were elevated in five of 11 patients with GO and in none without GO, whereas the difference of C. pneumoniae IgG titres between patients with GO and pair-matched controls did not reach significance (P<0.57). Chlamydia pneumoniae-specific DNA was found in 10 of 11 GO tissue samples pre-treatment. Azithromycin therapy effectively reduced GO and C. pneumoniae IgM titres. In residual GO, C. pneumoniae-specific DNA remained detectable after 1 year in all GO tissue samples despite azithromycin treatment. The C.pneumoniae IgM titres correlated with GO scores. Chlamydia pneumoniae infection is highly prevalent in CsA-induced GO. The infection can persist over a long period in residual GO despite short-term azithromycin therapy. The results indicate that CsA immunosuppression enhances C. pneumoniae infection rates in non-cardiovascular tissue.

Variability of cyclosporine exposure and its relevance to chronic allograft nephropathy: a case-control study.

Population data indicate that cyclosporine (CsA)-based immunosuppression has had relatively little effect on late renal allograft loss. For individual patients, however, the degree and variability of CsA exposure may be of prognostic importance. This case-control study has examined the contribution of these and other factors to the development of chronic allograft nephropathy (CAN) in patients receiving follow-up care in our unit. The electronic record was interrogated to identify adult, CsA-treated renal transplant recipients with CAN (group A) and CsA-treated controls with stable graft function for a minimum of 4 years posttransplantation and serum creatinine less than 200 micromol/L (group B). Age at transplantation, gender, years posttransplantation, donor source and age, kidney preservation time, human leukocyte antigen match, occurrence of delayed graft function, immunosuppressive regimen, weight-adjusted maintenance CsA dose, and coefficient of variation (CvarC0 ) of dose-adjusted CsA trough blood levels (C0/dose) were recorded (CvarC0 =[SD (C0/dose)/mean (C0/dose)]x100). Statistical analysis included binary logistic regression analysis. Three transplant recipients were excluded because of known noncompliance with immunosuppressive medication, leaving a study population of 102 patients. Recipient age (A<B, <0.001), CvarC0 (A>B, <0.01) and CsA dose (A>B, <0.02) were significantly different by univariate analysis. Only low recipient age ( P<0.001) and high CvarC0 ( P<0.02) were independent predictors of CAN in the regression model. Younger renal transplant recipients and those with highly variable CsA exposure are predisposed to developing CAN. Investigation of such patients may reveal correctable factors such as poor treatment compliance and lead to appropriate interventions.

RESPONSE OF WASHED PLATELETS FROM CYCLOSPORINE-A AND FK506- TREATED RENAL TRANSPLANT RECIPIENTS TO STIMULATORY AGONISTS DOES NOT DIFFER FROM CONTROLS

592 Enhanced platelet aggregation has been reported in ADP-stimulated platelet rich plasma (PRP) from CSA-treated renal transplant recipients (RTR's). In this study, washed platelets from 10 FK506-treated, 5 cyclosporine A-treated RTR's and 8 healthy controls were studied. 35 ml of whole anticoagulated blood was obtained from patients and controls and immediately centrifuged, the platelets isolated and washed using buffer and known platelet inhibitors. Platelet function was measured as initial velocity (IVEL), extent of aggregation (EXT), latency to response(LAT) and secretion(SEC) following the exposure to various final concentrations of collagen(19.2, 9.6, 4.8, 1.92μg/ml), ADP(192, 96, 48, 21.3, 10.6 μM), restocetin(1.34, 0.67, 0.27μg/ml), thrombin(0.096, 0.048, 0.019 units/ml), F-11 Mab (7.2, 3.6, 1.8, 0.4 μg/ml) and epinephrine(12, 6, 2.3, 1.06 μM), with simultaneous measurement of granular ATP release in the presence of luciferin luciferase reagent, using a Chronolog-Lumi aggregometer. CSA vs. FK506 groups did not differ when compared by t-test for age, sex, race hemoglobin, hematocrit, platelet count, albumin, cholesterol, iron and prednisone dose. The CSA pts had longer time since transplant compared with the FK506 pts.(39.0+12.1 vs. 2.6+0.6 months, p<0.005). By one-way ANOVA, FK506-treated patients did not differ significantly from cyclosporine-treated patients and controls when compared for latency, extent of aggregation, initial velocity and secretion for all reagents. There was no statistically significant difference in latency, extent, initial velocity and secretion across the various concentrations for each reagent among the 3 groups. We conclude, in our population: 1. Washed platelets from CSA and FK506 treated pts. behave similarly when exposed to stimulatory agonists; 2. Lack of enhanced aggregation in renal transplant pts. compared with controls, observed in this study, may reflect the use of washed platelets, in contrast to PRP used in previous studies; 3. Thus, the enhanced aggregation observed in PRP from CSA-treated patients and the increased thrombosis and atherogenesis observed in vivo in renal transplant recipients may be due to plasma effects on platelet function.

Excellent uricosuric efficacy of benzbromarone in cyclosporin-A-treated renal transplant patients: a prospective study

Patients on cyclosporin A (CsA) often develop hyperuricaemia and gout. In transplant patients the use of uricosuric drugs for treating hyperuricaemia may be preferable to allopurinol because of the known interaction of the latter with azathioprine. We therefore prospectively studied the uricosuric efficacy of 100 mg benzbromarone (Bbr;Desuric) daily in 25 CsA-treated renal transplant patients with stable graft function and hyperuricaemia (> 359 mumol/l for females, > 491 mumol/l for males). Benzbromarone decreased plasma uric acid from 579 + 18 mumol/l to 313 +/- 24 mumol/l (mean +/- SEM; P < 0.0001) and thereby normalized plasma uric acid in 21 of 25 patients. The remaining four patients had creatinine clearances between 21 and 25 ml/min, the lowest of the entire study group. Mean fractional clearance of uric acid increased from 5.4 +/- 0.4% to 17.2 +/- 1.0% (P < 0.001). The relative decrease of plasma uric acid closely correlated with baseline creatinine clearance (r = 0.67; P < 0.001). CsA trough values were not influenced. None of the patients experienced any significant side-effects. As an unexpected find-ing, urinary uric acid excretion increased from 2082 +/- 175 mumol/24 h to 3233 +/- 232 mumol/24 h after 4 weeks' treatment with benzbromarone. In conclusion, benzbromarone normalized plasma uric acid in all CsA-treated renal transplant recipients with a creatinine clearance > 25 ml/min. Due to its excellent efficacy and lack of significant side-effects, benzbromarone appears to be preferable to allopurinol in CsA-treated renal transplant recipients with a creatinine clearance over 25 ml/min.

Independent Effects of Cyclosporine and Prednisone on Posttransplant Hypercholesterolemia

To clarify the relative influences of cyclosporine (CsA) therapy, corticosteroid therapy, and other clinical variables on posttransplant hypercholesterolemia, total serum cholesterol levels were measured in 107 renal transplant recipients receiving one of three immunosuppression regimens: CsA and azathioprine (AZA) (group I); CsA, AZA, and prednisone (group II); or AZA and prednisone (group III). Multivariate analysis demonstrated that prednisone therapy, CsA therapy, patient age, and pretransplant cholesterol levels correlated independently with posttransplant cholesterol levels at last follow-up (ranging from 13 to 84 months after transplantation). In 32 patients successfully withdrawn from corticosteroid therapy and maintained on AZA and stable doses of CsA, serum cholesterol decreased from 6.55 +/- 1.1 mmol/L (253.5 +/- 43.1 mg/dL) to 5.27 +/- 1.2 mmol/L (203.9 +/- 45.6 mg/dL). Results of this analysis indicate that prednisone and CsA are independent factors in the pathogenesis of posttransplant hypercholesterolemia. Complete withdrawal of corticosteroids partially corrects hypercholesterolemia in CsA-treated renal transplant recipients.

Immunological monitoring in cyclosporine-treated patients

The immunosuppressive action of cyclosporine (CsA) in vivo is thought to primarily involve its inhibitory effect on lymphokine production by T lymphocytes. Most efforts to assess immunosuppression in CsA-treated patients have concentrated on measuring some aspect of activated T cell function. These have included monitoring of lymphocyte subsets and the appearance of activated T cell markers, assaying the production of lymphokines and the direct measurement of lymphokines in serum and urine, and most recently measurement of soluble interleukin-2 receptor (SIL2R). Using a new microparticle enzyme immunoassay (MEIA) in a preliminary study of 12 CsA-treated renal transplant recipients, we found significant increases in serum SIL2R levels in patients with rejection and we conclude that MEIA may have some use in the monitoring of CsA-treated patients.

THE EFFECTS OF DIETARY SUPPLEMENTATION WITH FISH OIL ON RENAL FUNCTION IN CYCLOSPORINE-TREATED RENAL TRANSPLANT RECIPIENTS

The effect of a daily supplementation of 6 g fish oil (30% C20:5 omega-3 (EPA) and 20% C22:6 omega-3 for three months on renal function variables was investigated in a placebo-controlled (6 g corn oil, 50% C18:2 omega-6) prospective, randomized, double-blind study in stable cyclosporine-treated renal transplant recipients, at least nine months after grafting. Ten patients ingested placebo capsules and eleven patients fish oil. When measuring glomerular filtration rate and effective renal plasma flow (ERPF) before (baseline [BL]) and after 3 months of oil ingestion nothing changed in the placebo-treated group: GFR-BL = 64.5 GFR-3 months = 60 ml/min/1.73m2 (NS; median, Wilcoxon test) ERPF BL = 229.5 and ERPF-3 months = 242.5 ml/min/1.73m2 (NS). In the fish oil-treated group GFR rose by 20.3% from GFR-BL = 56 to GFR-3 months = 68 ml/min/1.73m2 and ERPF by 16.4% from ERPF-BL 218 to ERPF-3 months = 245 ml/min/1.73m2, (P less than 0.01). In the placebo-treated group mean arterial pressure and calculated total renal vascular resistance (TRVR) did not change: MAP-BL = 106 mmHg and MAP-3 months = 109 mmHg, TRVR being 20856 dyne.sec/cm5 and 19862 dyne/sec/cm5, respectively (NS). In the fish oil-treated group MAP and TRVR fell by 8.6% and 21.1%, respectively: MAP-BL = 106 mmHg and MAP-3 months = 98 mmHg (P less than 0.01), TRVR-BL = 21952 dyne/sec/cm5 and TRVR-3 months = 17087 dyne/sec/cm5 (P less than 0.01). According to these results fish oil supplementation has considerable effects on renal function and blood pressure in stable CsA-treated renal transplant recipients.

PROTEINURIA IN CYCLOSPORINE-TREATED RENAL TRANSPLANT RECIPIENTS

Of 704 renal transplant recipients receiving long-term cyclosporine immunosuppression, 71 patients experienced proteinuria greater than 1 g/24 hr beyond the first month posttransplant. Eight patients displayed transient proteinuria, defined as lasting less than 3 months. In most cases this condition was attributed to biopsy-proved acute rejection. The transient proteinuria cohort experienced good graft outcome--namely, 87.5% one-year and 52.5% five-year actuarial graft survivals, which was similar to that observed in patients without proteinuria. In contrast, 52.4% of the 63 patients with nontransient proteinuria experienced graft loss within a median time of 6.1 months. The one- and five-year actuarial graft survivals in patients with nontransient proteinuria were 75.3% and 37.5%, respectively. Among the 63 patients with nontransient proteinuria, histopathologic diagnosis included chronic rejection in 19, transplant glomerulopathy in 14, acute rejection in 9, glomerulonephritis (GN) in 7 including 2 cases of membranous GN, and nonspecific interstitial fibrosis in 10 cases. Despite the overall poor prognosis for graft survival among the entire cohort of patients with nontransient proteinuria, the seven with allograft GN maintained prolonged graft function. They showed an 83.3% five-year actuarial graft survival versus 31.2% in patients with other causes of proteinuria (P = 0.043). These results suggest that posttransplant proteinuria in CsA-treated renal transplant recipients arises primarily as a consequence of allograft rejection and portends a poor graft outcome.

Failure of cyclosporine-treated renal allograft recipients to increase glomerular filtration rate following an amino acid infusion.

Renal allograft recipients treated with cyclosporine (CsA) have increased renal vascular resistance that falls when CsA is stopped. With the aim of identifying whether CsA-treated patients with excellent renal function also have an alteration in renal vascular tone and to investigate which vessels are affected, we have studied the response of GFR and effective renal plasma flow (ERPF) to an infusion of an amino acid solution in a group of 9 CsA-treated renal transplant recipients with a normal plasma creatinine concentration (104 +/- 3.8 mumol/L [mean +/- SEM]). A similar group of 9 azathioprine-treated patients with good renal function (91 +/- 3.6 mumol/L) were used as controls. The azathioprine group had significant increases in both GFR (22%, P less than 0.05) and ERPF (19%, P less than 0.05) following a protein load, whereas there was no increase in either function in the CsA group. Amino acid infusions increase GFR and ERPF in normal kidneys--at least in part by producing afferent glomerular arteriolar dilatation. The difference we found between the two groups indicates a direct effect of cyclosporine on intrarenal vascular tone, even when renal function is considered to be normal.