Natural Antibodies and Alloreactive T Cells Long after Kidney Transplantation

Background

The relationship between circulating effector memory T and B cells long after transplantation and their susceptibility to immunosuppression are unknown. To investigate the impact of antirejection therapy on T cell-B cell coordinated immune responses, we assessed IFN-γ-producing memory cells and natural antibodies (nAbs) that potentially bind to autoantigens on the graft.

Methods

Plasma levels of IgG nAbs to malondialdehyde (MDA) were measured in 145 kidney transplant recipients at 5-7 years after transplantation. In 54 of these patients, the number of donor-reactive IFN-γ-producing cells was determined. 35/145 patients experienced rejection, 18 of which occurred within 1 year after transplantation.

Results

The number of donor-reactive IFN-γ-producing cells and the levels of nAbs were comparable between rejectors and nonrejectors. The nAbs levels were positively correlated with the number of donor-reactive IFN-γ-producing cells (r _s = 0.39, p=0.004). The positive correlation was only observed in rejectors (r _s = 0.53, p=0.003; nonrejectors: r _s = 0.24, p=0.23). Moreover, we observed that intravenous immune globulin treatment affected the level of nAbs and this effect was found in patients who experienced a late ca-ABMR compared to nonrejectors (p=0.008).

Conclusion

The positive correlation found between alloreactive T cells and nAbs in rejectors suggests an intricate role for both components of the immune response in the rejection process. Treatment with intravenous immune globulin impacted nAbs.

Elevated plasma free thiols are associated with early and one-year graft function in renal transplant recipients

Background

Reduced free thiols in plasma are indicative of oxidative stress, which is an important contributor to ischaemia-reperfusion injury (IRI) in kidney transplantation leading to kidney damage and possibly delayed graft function (DGF). In a post-hoc, exploratory analysis of the randomised controlled CONTEXT trial, we investigated whether higher (i.e. less oxidised) plasma levels of free thiols as a biomarker of reduced oxidative stress are associated with a better initial graft function or a higher GFR.

Methods

Free thiol levels were measured in plasma at baseline, 30 and 90 minutes after reperfusion of the kidney as well as at Day 1, Day 5 and twelve months after kidney transplantation in 217 patients from the CONTEXT study. Free thiol levels were compared to the kidney graft function measured as the estimated time to a 50% reduction in plasma creatinine (tCr50), the risk of DGF and measured GFR (mGFR) at Day 5 and twelve months after transplantation.

Results

Higher levels of free thiols at Day 1 and Day 5 are associated with higher mGFR at Day 5 (p<0.001, r²_adj. = 0.16; p<0.001, r²_adj. = 0.25), as well as with mGFR at twelve months (p<0.001, r²_adj. = 0.20; p<0.001, r²_adj. = 0.16). However, plasma levels of free thiols at 30 minutes and 90 minutes, but not Day 1, were significantly higher among patients experiencing DGF.

Conclusion

Higher levels of plasma free thiols at Day 1 and Day 5, which are reflective of lower levels of oxidative stress, are associated with better early and late graft function in recipients of a kidney graft from deceased donors.

Trial registration

ClinicalTrials.gov Identifier:NCT01395719.

Fenofibrate Improved Interstitial Fibrosis of Renal Allograft through Inhibited Epithelial-Mesenchymal Transition Induced by Oxidative Stress

The best treatment for end-stage renal disease is renal transplantation. However, it is often difficult to maintain a renal allograft healthy for a long time following transplantation. Interstitial fibrosis and tubular atrophy (IF/TA) are significant histopathologic characteristics of a compromised renal allograft. There is no effective therapy to improve renal allograft function once IF/TA sets in. Although there are many underlying factors that can induce IF/TA, the pathogenesis of IF/TA has not been fully elucidated. It has been found that epithelial-mesenchymal transition (EMT) significantly contributes to the development of IF/TA. Oxidative stress is one of the main causes that induce EMT in renal allografts. In this study, we have used H₂O₂ to induce oxidative stress in renal tubular epithelial cells (NRK-52e) of rats. We also pretreated NRK-52e cells with an antioxidant (N-acetyl L-cysteine (NAC)) 1 h prior to the treatment with H₂O₂. Furthermore, we used fenofibrate (a peroxisome proliferator-activated receptor α agonist) to treat NRK-52e cells and a renal transplant rat model. Our results reveal that oxidative stress induces EMT in NRK-52e cells, and pretreatment with NAC can suppress EMT in these cells. Moreover, fenofibrate suppresses fibrosis by ameliorating oxidative stress-induced EMT in a rat model. Thus, fenofibrate may effectively prevent the development of fibrosis in renal allograft and improve the outcome.

Metabolomics for clinical use and research in chronic kidney disease

Chronic kidney disease (CKD) has a high prevalence in the general population and is associated with high mortality; a need therefore exists for better biomarkers for diagnosis, monitoring of disease progression and therapy stratification. Moreover, very sensitive biomarkers are needed in drug development and clinical research to increase understanding of the efficacy and safety of potential and existing therapies. Metabolomics analyses can identify and quantify all metabolites present in a given sample, covering hundreds to thousands of metabolites. Sample preparation for metabolomics requires a very fast arrest of biochemical processes. Present key technologies for metabolomics are mass spectrometry and proton nuclear magnetic resonance spectroscopy, which require sophisticated biostatistic and bioinformatic data analyses. The use of metabolomics has been instrumental in identifying new biomarkers of CKD such as acylcarnitines, glycerolipids, dimethylarginines and metabolites of tryptophan, the citric acid cycle and the urea cycle. Biomarkers such as c-mannosyl tryptophan and pseudouridine have better performance in CKD stratification than does creatinine. Future challenges in metabolomics analyses are prospective studies and deconvolution of CKD biomarkers from those of other diseases such as metabolic syndrome, diabetes mellitus, inflammatory conditions, stress and cancer.

Association of interleukin 18-607A/C and -137C/G polymorphisms with oxidative stress in renal transplant recipients

Objectives IL-18 mediates various inflammatory and oxidative responses including renal injury, fibrosis, and graft rejection. It has been reported that the promoter -607 and -137 polymorphisms of IL-18 influence the level of IL-18. This prospective observational study investigated the association between oxidative stress with IL-18-607 and -137 polymorphisms in renal transplant recipients. Patients and methods This study included 75 renal transplant recipients (28 female, 47 male) from living-related donors. Blood samples were collected immediately before and after transplantation at day 7 and month 1. Serum IL-18, creatinine, cystatin C, CRP, and oxidative stress markers (TOS, TAC) were measured. The Oxidative Stress Index (OSI) was calculated. Polymorphisms of the promoter region of the IL-18 gene, IL18-607A/C, and -137C/G were determined by analysis of a "real-time PCR/Melting curve". Results Serum creatinine, cystatin C, CRP, IL-18, TOS, and OSI levels significantly decreased after transplantation. Post-transplant levels of serum TAC and estimated GFR demonstrated consistent significant increases. Serum IL-18 levels were significantly higher in patients with IL-18-137 GG and IL-18-607 CC genotypes before transplantation. Conclusion Our results indicate that the IL-18-137 GG and -607 CC genotypes contribute to higher IL-18 levels; however, the influence of these polymorphisms on oxidative stress has not been observed.

Evaluation of oxidant and antioxidant status in living donor renal allograft transplant recipients

The objective of this study was to evaluate the oxidant and antioxidant status in living donor renal allograft transplant recipients. Ninety-two renal transplant recipients with mean age of 34.75 ± 11.22 years were included in the present study. Venous samples of the recipients were drawn: before the transplant (baseline), 5 min after reperfusion, and 2 weeks after transplant. Samples were processed for the measurement of markers of oxidant and antioxidant status viz. malondialdehyde, catalase, glutathione peroxidase, reduced glutathione, ascorbic acid, and total antioxidant system. The mean baseline levels of reduced glutathione, ascorbic acid, and total antioxidant system were 1.61 ± 0.84 mg/g hemoglobin, 3.64 ± 1.49 mg/dL, and 1.42 ± 0.14 mmol/L which decreased at 5 min after reperfusion to 1.32 ± 0.72 (p = 0.010), 2.96 ± 1.25 (p = 0.002), and 1.36 ± 0.12 (p = 0.042), respectively. The malondialdehyde levels increased from a baseline value of 3.11 ± 1.02 µmol/mL to 3.32 ± 1.09 at 5 min after reperfusion (p = 0.344) and 4.01 ± 1.21 (p = 0.000) at 2 weeks. Glutathione peroxidase level decreased from 68.59 ± 32.79 units/g hemoglobin (baseline) to 63.65 ± 32.92 at 5 min after reperfusion (p = 0.530) and increased significantly at 2 weeks to 86.38 ± 37.18 (p = 0.00). There was no significant change in the catalase level. In living donor renal transplantation, oxidative stress starts after reperfusion and is reflected by fall in antioxidant factors and enzymes in the early period. Over the next 2 weeks, there is increased oxidative stress and simultaneous strengthening of antioxidant system which is implied by increase in malondialdehyde and improvement in the markers of antioxidant status.

Oxidative stress in kidney transplantation: malondialdehyde is an early predictive marker of graft dysfunction

BACKGROUND

Oxidative stress is one of the most important components of the ischemia-reperfusion process after kidney transplantation (KTx) and increases with graft dysfunction.

METHODS

This prospective study was conducted on 40 consecutive KTx recipients to evaluate time-dependent changes in oxidative stress-related parameters within the first week after KTx and to assess their performance in predicting delayed graft function (DGF=dialysis requirement during initial posttransplant week) and graft function at 1 year. Blood samples were collected before (day 0) and after KTx (days 1, 2, 4, and 7). Total antioxidant capacity, plasma levels of malondialdehyde (MDA), and activities of glutathione peroxidase, glutathione reductase and superoxide dismutase were measured. Multivariable linear mixed and linear regression models, receiver-operating characteristic (ROC), and areas under ROC curves (AUC-ROC) were used.

RESULTS

At all time points after KTx, mean MDA levels were significantly higher in patients developing DGF (n=18). Shortly after KTx (8-12 hr), MDA values were higher in DGF recipients (on average, +0.16 μmol/L) and increased further on following day, contrasting with prompt functioning recipients. Day 1 MDA levels accurately predicted DGF (AUC-ROC=0.90), with a performance higher than SCr (AUC-ROC=0.73) and similar to cystatin C (AUC-ROC=0.91). Multivariable analysis revealed that MDA levels on day 7 represented an independent predictor of 1-year graft function. Antioxidant enzyme activities were not significantly changed during the study period and were not predictors of 1-year graft function.

CONCLUSIONS

Increased MDA levels on day 1 after KTx might be an early prognostic indicator of DGF, and levels on day 7 might represent a useful predictor of 1-year graft function.

[Importance of selenium homeostasis in chronic and end-stage kidney diseases]

Selenium is an essential trace element for the human body with a significant antioxidant effect. Selenium deficiency and excess are both detrimental for proper functioning of the human body. The possible association between selenium deficiency and acute or chronic renal disease, along with their complications has been less intensively investigated, however, there are firm data showing that selenium deficiency and renal failure increase the risk of both coronary artery disease and total mortality. Further studies revealed that selenium deficiency increases the risk of death due to infection in patients treated with hemodialysis through dysfunction of the immune system. However, there are no data whether the imbalance of selenium metabolism, especially selenium deficiency, could cause chronic kidney disease or renal failure. As far as results of selenium measurements, there is convincing evidence that protein loss and renal replacement treatment reduce serum selenium levels. Despite some contradictory results obtained from various studies regarding selenium deficiency in chronic kidney diseases, it seems that selenium supplementation may be beneficial in many patients with severe or end-stage kidney disease including those treated with dialysis.

Glutathione S-transferase M1 gene polymorphism is associated with susceptibility to impaired long-term allograft outcomes in renal transplant recipients

BACKGROUND

Despite improved post-transplantation care, progress in long-term kidney allograft survival of diabetic renal transplant recipients (pre-DM RTR) is worse than that of non-diabetic recipients (non-DM). We hypothesized that there are other potential risk factors, that predispose RTR to adverse renal allograft outcomes.

METHODS

A total of 323 transplant recipients who underwent renal transplantation between March 2000 and January 2008 were recruited. The composite end-point consisted of serum creatinine (SCr) doubling, graft failure, and death. Baseline clinical data were recorded, and polymerase chain reaction-restriction fragment length polymorphism measurements of interleukin (IL)-4, IL-10, IL-23, glutathione S-transferase (GST)A1, GSTM1, and GSTP1 polymorphisms were determined. The risk factors for developing the primary outcome were analyzed among these clinical and genetic factors.

RESULTS

Within a mean follow-up of 71.1 ± 24 months, there were 43 (13.3 %) patients with the primary outcome. Stepwise multivariate Cox regression analysis was used to determine the risk factors for the primary outcome of RTR. Renal transplant recipients who possessed the GSTM1 null genotype had a 2.2-fold risk (95 % CI: 1.10-4.40; P = 0.026) of developing the primary outcome. Additionally, RTR that had DM before transplantation (aHR: 3.31; 95 % CI: 1.77-6.20; P = 0.0002) or changes in SCr 6 to 12 months after transplantation (aHR: 2.83; 95 % CI: 1.29-6.19; P = 0.0095) had an increased risk of developing the primary outcome.

CONCLUSIONS

In addition to the adverse role played by DM, the GSTM1 null genotype also has an unfavorable influence on the long-term allograft outcome of RTR.

Plasma glutathione peroxidase activity in kidney recipients with and without adverse outcome

Kidney function is routinely monitored utilizing classic biochemical parameters including serum or plasma creatinine (Cr), and blood urea nitrogen (BUN) concentrations. This study demonstrates that the simultaneous assessment of plasma glutathione peroxidase (pGPx) and Cr levels provides a better strategy for the immediate follow-up of kidney function in organ recipients. Kidney recipients (Krs; n = 22) were recruited. Blood sampling schedule commenced at day 1 (pre-transplantation) and post-transplantation days (i.e., everyday from 1 until day 14, and thereafter on days 21, 28, 35, 42, 49, and 56). pGPx was measured spectrophotometrically. Candidates for transplantation exhibited lower pGPx than control subjects (42 ± 24 vs. 143 ± 31 U/L; p < 0.005). In Krs with a stable post-transplant outcome, pGPx increased to a maximum at day 28 (214 ± 61 U/L). In a Kr diagnosed with acute tubulonecrosis, pGPx provided a better predictive value (threefold increase) than Cr. In a Kr diagnosed with acute rejection, the increment in Cr values was found to be more pronounced than in pGPx values. The pGPx test is simple, inexpensive and automatable, and should be a valuable diagnostic tool of kidney function in organ recipients with and without troublesome outcome for the follow-up during hospitalization period.

Immunosuppressant regimen based on sirolimus decreases aortic stiffness in renal transplant recipients in comparison to cyclosporine

Whether or not a cyclosporine A (CsA)-free immunosuppressant regimen based on sirolimus (SRL) prevents aortic stiffening and improves central hemodynamics in renal recipients remains unknown. Forty-four patients (48 ± 2 years) enrolled in the CONCEPT trial were randomized at week 12 (W12) to continue CsA or switch to SRL, both associated with mycophenolate mofetil. Carotid systolic blood pressure (cSBP), pulse pressure (cPP), central pressure wave reflection (augmentation index, AIx) and carotid-to-femoral pulse-wave velocity (PWV: aortic stiffness) were blindly assessed at W12, W26 and W52 together with plasma endothelin-1 (ET-1), thiobarbituric acid-reactive substances (TBARS) and superoxide dismutase (SOD) and catalase erythrocyte activities. At W12, there was no difference between groups. At follow-up, PWV, cSBP, cPP and AIx were lower in the SRL group. The difference in PWV remained significant after adjustment for blood pressure and eGFR. In parallel, ET-1 decreased in the SRL group, while TBARS, SOD and catalase erythrocyte activities increased in both groups but to a lesser extent in the SRL group. Our results demonstrate that a CsA-free regimen based on SRL reduces aortic stiffness, plasma endothelin-1 and oxidative stress in renal recipients suggesting a protective effect on the arterial wall that may be translated into cardiovascular risk reduction.

Endothelial nitric oxide synthase (eNOS) gene polymorphism in early term chronic allograft nephropathy

Chronic allograft nephropathy (CAN) is a complex phenomenon caused by underlying kidney disease with superimposed enviromental and genetic factors. CAN development begins with progressive renal microvascular injury. Endothelial cells play key roles in the regulation of vascular tone, permeability, and remodeling. A reduction in basal nitric oxide (NO) release as a result of genetic variation in endothelial NO synthase (eNOS) function may predispose to hypertension, thrombosis, vasospasm, and atherosclerosis, all contributing to the development of CAN. We analyzed the G894T mutation at exon 7 of the eNOS gene in relationship to CAN among 81 children with renal transplantations. The 20 patients who developed CAN underwent renal biopsies for histological confirmation. Proteinuria and hypertension were observed in CAN. We selected 173 healthy reference subjects. The G894T polymorphism of the eNOS gene was determined by PCR-restriction fragment-length polymorphism analysis. The group included 33 male and 48 female subjects who received 32 living-related grafts and 49 from deceased donors (DD) donors. Donor age (y) was 32.7 +/- 13.7 and the HLA A,B,DR mismatch number of the cadaveric cases was 3.5 +/- 0.79. The distribution of the genotypes were ENOS GG/GT/TT 48%, 33%, 19%, respectively. G-alleles frequency was 64.8%; T-allele frequency was 35.2%. ENOS G894T gene polymorphism did not seem to influence long-term renal allograft outcome. Recipient ENOS G894T gene polymorphism did not alter the risk of chronic allograft failure. Even if NO synthesis and bioactivity are influenced by this polymorphism, many vasoactive factors may have roles to suppress the advantageous effects of NO.

Oxidative stress as a common pathway to chronic tubulointerstitial injury in kidney allografts

A major challenge for kidney transplantation is to dissect out the identifiable causes of chronic allograft tubulointerstitial fibrosis and to develop cause-specific treatment strategies. There has been a recent interest in the role of oxidative stress (OS) as a mediator of injury in chronic allograft tubular atrophy (TA) and interstitial fibrosis (IF). A review of the literature and data from my laboratory studying chronic allograft TA/IF in rat, rhesus monkey, and human kidneys suggests that OS is increased in graft-infiltrating macrophages, activated myofibroblasts, interstitium, and areas of tubular injury. Chronic allograft OS may be induced by inflammation, abnormal tissue oxygenation, immunosuppressant drugs, and comorbid clinical conditions including diabetes, hypertension, proteinuria, anemia, and dyslipidemia. Moreover, OS-induced chronic TA/IF is associated with signaling pathways including inflammation, apoptosis, hypoxia, and epithelial-to-mesenchymal transition. Most of these injury pathways participate in a self-perpetuating cycle with OS. In conclusion, evidence suggests that OS is a common mechanism of injury in chronic allograft TA/IF. However, most available data demonstrate a correlation and no causal relationship. Furthermore, the extent to which TA/IF is dependent on OS is unknown. These questions may be answered by prospective randomized placebo-control trials examining the role of select antioxidants in the prevention of chronic allograft TA/IF.

Correlation between oxidative stress and immunosuppressive therapy in renal transplant recipients with an uneventful postoperative course and stable renal function

BACKGROUND

Reactive oxygen species (ROS) are important mediators of cellular damage and lipid peroxidation is the most important expression of ROS-induced oxidative stress. Recent studies have suggested that increased plasma malondialdehyde (MDA) levels are a consequence of specific immunosuppressive therapies. This study aims at investigating the relation between oxidative stress and immunosuppressive therapies in renal transplant patients with stable renal function and uneventful postoperative course.

METHODS

The study group included 26 renal patients. Two groups of renal transplant recipients, treated with a different combination of immunosuppressive agents were studied (Group A: CyA, MMF, Steroids and Basiliximab, Group B: Tacrolimus, MMF, Steroids and Daclizumab). All patients had an uneventful postoperative course. Plasma MDA levels were measured before transplantation, 1 and 6 months after. Plasma concentration of endogenous creatinine (Cr) was used as a measure of stable renal function.

RESULTS

Levels of MDA were increased before the transplantation in all renal patients (MDA: 7.81 +/- 4.81, normal levels: 2.23-4.08 nmol/ml, P < 0.05). Combined therapy with CyA was associated with high values of MDA at 6 months measurement after transplantation. However this tendency of increased MDA levels did not achieve a statistical significance (Group A: 6.97 vs. 9.06 nmol/ml, P>0.05). On the contrary, statistically significant diminution of MDA levels was observed in Group B patients (Tacrolimus-MMF-steroids) at 6 months measurement after transplantation. (Group B: 8.61 vs. 4.11 nmol/ml, P<0.02<0.05).

CONCLUSIONS

Immunosuppressive combined therapy with CyA was associated with the high values of MDA that were measured posttransplantly. Our study provides strong evidence that Tacrolimus is significantly associated with improved free radical metabolism.

Cyclosporine A induced changes to plasma and erythrocyte antioxidant defences

Organ transplant recipients develop pronounced cardiovascular disease, and decreased antioxidant capacity in plasma and erythrocytes is associated with the pathogenesis of this disease. These experiments tested the hypothesis that the immunosuppressant cyclosporine A (CsA) alters erythrocyte redox balance and reduces plasma antioxidant capacity. Female Sprague-Dawley rats were randomly assigned to a control or CsA treated group. Treatment animals received 25 mg/kg/day of CsA via intraperitoneal injection for 18 days. Control rats were injected with the same volume of the vehicle. Three hours after the final CsA injection, rats were exsanguinated and plasma analysed for total antioxidant status (TAS), alpha-tocopherol, malondialdehyde (MDA), and creatinine. Erythrocytes were analysed for superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and glucose-6-phosphate dehydrogenase (G6PD) activities, alpha-tocopherol, and MDA. CsA administration resulted in a significant (P < 0.05) decrease in plasma TAS and significant increases (P < 0.05) in plasma creatinine and MDA. Erythrocyte CAT was significantly (P < 0.05) increased in CsA treated rats compared to controls. There were no significant differences (P > 0.05) in erythrocyte SOD, GPX, G6PD, alpha-tocopherol or MDA between groups. In summary, CsA alters erythrocyte antioxidant defence and decreases plasma total antioxidant capacity.

Heat Shock Protein 27 in Chronic Allograft Nephropathy: A Local Stress Response

BACKGROUND

Heat shock protein (HSP) 27 plays a cytoprotective role through its antioxidant, antiapoptotic, and actin-stabilizing properties during cell stress. The authors hypothesized that HSP27 is involved in chronic allograft nephropathy (CAN), a chronic state of inflammation and stress.

METHODS

The authors used the Fisher 344-to-Lewis model of CAN. Transplants were performed in 3-month-old recipient rats. HSP27 mRNA and protein levels were determined using semiquantitative polymerase chain reaction, microarray (stress-toxicity, GEArray) analyses, gene sequencing, immunoblotting, and immunohistochemical analyses at 10 days and 6 months posttransplant. P38 mitogen-activated protein kinase (MAPK), manganese (Mn) superoxide dismutase (SOD), copper-zinc (CuZn) SOD, FasL, Bax, hypoxia-inducible factor (HIF)-1alpha, and CD3 lymphocytes were studied in parallel as selective biomarkers of oxidative stress (OS), apoptosis, hypoxia, and graft-infiltrating immune cells.

RESULTS

Six months after transplantation, kidney allografts displayed histologic and functional features of CAN, including tubular atrophy, interstitial fibrosis, glomerulosclerosis, and increased proteinuria and serum creatinine levels. HSP27 mRNA and protein levels in CAN were reduced by 50% and 85%, respectively (P=0.04). Immunohistochemical analyses revealed a "shift" in HSP27 from the medulla to the cortex in allografts with CAN. Bax, phosphorylated p38-MAPK, HIF-1alpha, and MnSOD followed a parallel relocation pattern. CD3 lymphocyte density and tubular FasL expression were also greater in the cortex of allografts with CAN. Time-course analyses revealed that most of these changes were present as early as 10 days posttransplant.

CONCLUSIONS

The shift of HSP27 from the medulla to the cortex, combined with greater CD3, p38-MAPK, Bax, FasL, HIF-1alpha, and MnSOD immunoreactivity in this area of the kidney, likely represents an allograft-level response to CAN-related OS-hypoxia.

Comparison between swallowing and chewing of garlic on levels of serum lipids, cyclosporine, creatinine and lipid peroxidation in renal transplant recipients

Hyperlipidemia and increased degree of oxidative stress are among the important risk factors for Atherosclerosis in renal transplant recipients (RTR). The Medical treatment of hyperlipidemia in RTR because of drugs side effects has been problematic, therefore alternative methods such as using of Garlic as an effective material in cholesterol lowering and inhibition of LDL Oxidation has been noted. For evaluation of garlic effect on RTR, 50 renal transplant patients with stable renal function were selected and divided into 2 groups. They took one clove of garlic (1 gr) by chewing or swallowing for two months, after one month wash-out period, they took garlic by the other route. Results indicated that although lipid profile, BUN, Cr, serum levels of cyclosporine and diastolic blood pressure did not change, Systolic blood pressure decreased from 138.2 to 132.8 mmHg (p=0.001) and Malondialdehyde (MDA) decreased from 2.4 to 1.7 nmol/ml (p=0.009) by swallowing route, Cholesterol decreased from 205.1 to 195.3 mg/dl (p=0.03), triglyceride decreased from 195.7 to 174.8 mg/dl (p=0.008), MDA decreased from 2.5 to 1.6 nmol/ml (p=0.001), systolic blood pressure decreased from 137.5 to 129.8 mmHg (p=0.001), diastolic blood pressure decreased from 84.6 to 77.6 mmHg (p=0.001) and Cr decreased from 1.51 to 1.44 mg/dl (p=0.03) by chewing route too. However HDL, LDL and cyclosporine serum levels had no significant differences by both of swallowing and chewing routes. We conclude that undamaged garlic (swallowed) had no lowering effect on lipid level of serum. But Crushed garlic (chewed) reduces cholesterol, triglyceride, MDA and blood pressure. Additionally creatinine reduced without notable decrease in cyclosporine serum levels may be due to cyclosporine nephrotoxicity ameliorating effect of garlic.

Influence of predialysis oxidative stress on peroxidation processes after renal transplantation

Oxidative stress occurs as a result of reactive oxygen species (ROS) overproduction. The content of carbonyl groups (CG), malonyldialdehyde, 4-hydroxynonenal (MDA, 4-HNE) represent markers of protein and lipid peroxidation processes, respectively. The aim of the present study was to determine CG and MDA/4-HNE in the serum of 30 hemodialyzed patients (-HD; 13 men, 17 women of mean age 47.7 +/- 15.3 years) before and after a hemodialysis session, of 20 transplant patients (TX; 10 men, 10 women of mean age 40.7 +/- 11.3 years) before and after the procedure (RT), and of a control group (n = 47; including 30 women, 17 men of mean age 38.7 +/- 14.0 years). The CG content was evaluated using the 2,4-dinitrophenylhydrazine assay and MDA/4-HNE by the Oxis Bioxytech colorimetric method. Among the HD group the concentrations of MDA/4-HNE and CG were higher than control subjects (P <.05). In the HD group CG concentrations before and after dialysis session were similar while MDA/4-HNE concentrations were higher before the dialysis session (P <.01). One day after RT, MDA/4-HNE and CG concentrations had increased but at 7 days they had decreased and the CG level was increased. A high production of ROS can be assumed in dialysis patients. MDA/4-HNE concentrations, however, decreased after the dialysis treatment, because as low-weight molecules they diffused across the dialysis filter. On the first day after RT a high intensity of lipid and protein peroxidation was observed. During the first week after RT, accumulation of protein peroxidation products was observed but simultaneously lipid peroxidation product concentrations decreased due to quick metabolism. The intensity of lipooxidation during first day after RT seems to be dependent upon the ischemia time.

Telomere shortening and cellular senescence in a model of chronic renal allograft rejection

Cellular senescence has been suggested to play a role in the deterioration of renal graft function and has been linked to telomere shortening. We have investigated markers of cellular senescence in the F344 to LEW rat model of chronic renal transplant rejection. Syngeneic and LEW to F344 transplants were used as controls. Substantial telomere shortening was observed in all transplants, including allogeneic and syngeneic grafts from day 7 post-transplant onwards. Ischemia of native F344 kidneys was already sufficient to induce telomere shortening. It is known that shortened telomeres can activate cell cycle regulators, such as p21 and p16. Accordingly, all cases showed a transient p21 increase, with a maximum at day 7 and a sustained expression of p16. Importantly, senescence-associated beta-galactosidase staining, a cytological marker for senescence, was only observed in tubular epithelial cells of chronically rejecting F344 allografts from day 30 post-transplantation onwards. Long-term surviving LEW allografts or syngeneic F344 grafts were negative for senescence-associated beta-galactosidase. In conclusion, ischemia during transplantation results in telomere shortening and subsequent activation of p21 and p16, whereas senescence-associated beta-galactosidase staining is only present in chronically rejecting kidney grafts.

Antioxidant enzyme determination and a study of lipid peroxidation in renal transplantation

The aim of this study was to evaluate the antioxidant enzymes, catalase (CAT) and superoxide dismutase (SOD), in renal transplant patients and at the same time to report on the degree of lipid peroxidation observed in these patients. In order to do so we measured erythrocyte malondialdehyde (MDA), a product of lipid peroxidation. These measurements were made at different times: before the transplant, 48 h after the transplant, a week after the transplant and two weeks after the transplant. The values reported were compared with a control group. The results showed that there was a higher MDA level in the transplant group than in the control group one week after the transplant. In addition, two weeks after the transplant, the activities of CAT and SOD were higher in the transplant group than in the control group.

Measurement of free radicals and NO by chemiluminescence to identify the reperfusion injury in renal transplantation

Oxygen free radicals are generated during the reperfusion of ischaemic organs. Several experimental studies have demonstrated that the damage produced by reperfusion can be prevented by a scavenger of free radicals. Furthermore, a significantly improved 5 year graft survival rate after cadaveric renal transplantation has been reported in patients treated with scavengers of free radicals (Land et al., 1993). Therefore, a question remains to be answered: whether a routine monitoring of the radical-mediated reperfusion injury with renal transplantation is useful, and whether there is a necessity for a generalized protective treatment in transplant patients. In a prospective trial, we evaluated a group of eight patients during and after renal cadaveric transplantation (three men, five women), using the chemiluminometric measurement of serum free radicals and NO. The serum quantities of free radicals and NO were significantly increased after reperfusion of the transplant kidney (p < 0.02). The mean time of noticeably increased levels of serum free radicals was 4.8 +/- 1.2 h after reperfusion. The results thus showed an increased liberation of free radicals in the peripheral blood of transplant recipients as possible evidence of free radicals-mediated reperfusion injury in renal transplantation. The generation of free radicals measured by chemiluminescence allow a controlled therapy to decrease the generation of free radicals with antioxidants during the early transplantation period e.g. in older recipients.

Urinary F2-isoprostanes formation in kidney transplantation

BACKGROUND

Oxygen free-radical mediated lipid peroxidation has been implicated in many diseases such as chronic renal failure, hemodialysis and chronic kidney transplant rejection. However, insight into the role of free radical generation in kidney transplantation has been constrained by the limitations of current indexes of oxidant stress in vivo. Isoprostaglandin F2alpha type-III (iPF2alpha-III, formerly known as 8-iso-prostaglandin F2alpha) is emerging as a reliable marker of oxidant stress in vivo. The purpose of our study was to investigate iPF2alpha-III formation as an index of lipid peroxidation in the 5 d following kidney transplantation.

METHODS

Urinary iPF2alpha-III measurements were performed by enzyme immunoassay from day I to 5 in 11 patients undergoing kidney transplantation. Results were compared with 11 healthy volunteers matched in sex, age and cigarette smoking.

RESULTS

Urinary excretion of iPF2alpha-III at day 1 did not significantly differ between control and transplant group (111 +/- 17 vs. 92 +/- 10 pM/ mM creatinine, respectively, NS). Urinary iPF2alpha-III levels did not differ between day 1 to 5, and were not correlated to cold ischaemia time.

CONCLUSION

Our study shows no evidence of enhanced lipid peroxidation in the first 5 d following kidney transplantation.