Activity of CuZn-superoxide dismutase, catalase and glutathione peroxidase in erythrocytes in kidney allografts during reperfusion in patients with and without delayed graft function

BICD1 and Chromosome 18 Polymorphisms Associated With Recipients' Telomere Length Affect Kidney Allograft Function After Transplantation

BACKGROUND

Reports regarding recipient's nonmodifiable genetic factors affecting telomerase activity and thus allograft function are lacking. Therefore the aim of this study was to analyze the associations between recipients' rs2735940 hTERT, rs2630578 BICD1, and rs7235755 chromosome 18 polymorphisms and kidney function after transplantation.

METHODS

The study enrolled 119 white Polish kidney allograft recipients (64 men, 55 women; overall mean age, 47.3 ± 14.0 y). To identify genotypes of the studied polymorphisms, real-time polymerase chain reaction was performed.

RESULTS

There were statistically significant differences in distribution of rs7235755 chromosome 18 polymorphism genotypes and alleles between recipients with delayed graft function (DGF) and without DGF (P = .03). The presence of A allele was significantly associated with higher risk of DGF occurrence (AA + GA vs GG: OR, 3.25 [95% CI, 1.16-9.14]; P = .02; GA vs GG: OR, 4.00 [1.35-11.82]; P = .01). Analysis of the rs2630578 BICD1 gene polymorphism genotypes revealed statistically significant differences in long-term creatinine concentrations. The presence of C allele of this polymorphism was significantly associated with higher creatinine concentrations 24, 36, and 18-48 months after transplantation (GC + CC vs GG: P = .008, P = .008, and P = .01, respectively).

CONCLUSIONS

Recipients' polymorphisms of genes associated with telomere length, BICD1 and chromosome 18, but not hTERT, affect kidney allograft early and long-term function after transplantation. There is an urgent need for explanation of these observations in genome-wide association studies.

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.

Applications of nanoparticles in the detection and treatment of kidney diseases

Nanoparticles have emerged in the medical field as a technology well suited for the diagnosis and treatment of various disease states. They have been heralded as efficacious in terms of improved therapeutic efficacy and reduction of treatment side effects in some cases. Various nanomaterials have been developed that can be tagged with targeting moieties as well as with drug delivery and imaging capability or a combination of both as a theranostic agent. These nanomaterials have been investigated for treatment and detection of various pathological conditions. The emphasis of this review is to demonstrate current research and clinical applications for nanoparticles in the diagnosis and treatment of kidney diseases.

Perioperative release of pro-regenerative biochemical signals from human renal allografts subjected to ischemia-reperfusion injury

Complement-derived molecules modulate the intensity of renal ischemia-reperfusion injury and may lead to the generation of biochemical signals [such as stromal-derived factor-1 (SDF-1) or sphingosine-1-phosphate (S1P)], which stimulate tissue/organ regeneration after injury. We tested the association between perioperative C5b-9/membrane attack complex (MAC) levels and intensified erythrocyte lysis, and asked whether significant changes in the levels of pro-regenerative substances occur during the early phase of renal allograft reperfusion. Seventy-five recipients were enrolled and divided into the early, slow, and delayed graft function (DGF) groups. Perioperative blood samples were collected from the renal vein during consecutive minutes of reperfusion. Extracellular hemoglobin (eHb), albumin (plasma S1P transporter), 8-iPF2α-III isoprostane, SDF-1 and S1P concentrations were measured. Throughout the reperfusion period, erythrocyte lysis intensified and was most pronounced in the DGF group. However, perioperative eHb levels did not correlate significantly with C5b-9/MAC values, but rather with the intensity of oxidative stress. No significant changes were observed in S1P, its plasma transporter (albumin) or SDF-1 levels, which were relatively low in all groups throughout the reperfusion period. Our study therefore demonstrates that no known biochemical signal for bone marrow-derived stem cell mobilization is released from human renal allografts to the periphery during the early phase of reperfusion.

Clinical analysis of perioperative complement activity during ischemia/reperfusion injury following renal transplantation

BACKGROUND AND OBJECTIVES

The complement cascade seems to be an important mediator modulating renal ischemia/reperfusion injury. This study analyzed whether significant changes occur in the levels of a terminal panel of complement molecules (C3a, C5a, and C5b-9/membrane attack complex) during the early phase of human kidney allograft reperfusion and evaluated the potential association of these changes with clinical post-transplant graft function in kidney transplant recipients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Seventy-five renal transplant recipients undergoing transplantation between 2004 and 2006 were enrolled in the study and divided into early, slow, and delayed graft function groups. Blood samples were collected perioperatively during consecutive minutes of allograft reperfusion from the renal vein. Levels of complement molecules were measured using ELISA.

RESULTS

Analysis revealed no significant changes in C3a and C5a levels throughout reperfusion. The main complement molecule that was significantly associated with post-transplant graft function was C5b-9/membrane attack complex; throughout the reperfusion period, perioperative levels of C5b-9/membrane attack complex were around two to three times higher in delayed graft function patients than early and slow graft function individuals (P<0.005). In addition, C5b-9/membrane attack complex levels had a relatively high clinical sensitivity and specificity (70%-87.5%) for the prediction of early and long-term (1 year) post-transplant allograft function.

CONCLUSIONS

This clinical study supports a role for the complement cascade in delayed graft function development. However, additional studies are needed to elucidate the exact mechanisms responsible for this phenomenon. In addition, perioperative measurements of C5b-9/membrane attack complex are highlighted as promising potential clinical markers of post-transplant renal allograft function.

The association of -262C/T polymorphism in the catalase gene and delayed graft function of kidney allografts

BACKGROUND

Catalase is an intracellular antioxidant enzyme that is mainly located in cellular peroxisomes and in the cytosol. This enzyme plays a significant role in the development of tolerance to oxidative stress in the adaptive response of cells and tissues. The aim of the present study was to examine the association between the -262C/T polymorphism in the catalase gene and delayed graft function (DGF), acute rejection and chronic allograft nephropathy of kidney allografts.

METHODS

One hundred eighty-seven recipients of first renal transplants were included in the study. The histories of the patients were analysed regarding DGF, acute rejection and chronic allograft nephropathy. The polymorphism -262C/T in the catalase gene was analysed using the polymerase chain reaction--restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

The risk of DGF was significantly lower in T allele carriers compared with CC homozygotes: odds ratio = 0.34, 95% confidence interval = 0.17-0.67, P = 0.001. There were no statistically significant associations between the studied polymorphism and acute rejection or chronic allograft nephropathy.

CONCLUSION

The results of this study suggest that -262C/T polymorphism in the catalase gene is associated with DGF in kidney allograft recipients.

Clinical evidence of the association between serum perioperative changes in xanthine metabolizing enzymes activity and early post-transplant kidney allograft function

BACKGROUND

Xanthine oxidoreductase (XOR) and its active forms, dehydrogenase (XD) and oxidase (XO), act as double-edged swords during ischemia-reperfusion injury. On the one hand, their action generates antioxidants, such as uric acid (UA); however, they may strongly enhance production of free radicals. In this study, we examined the association between post-transplant graft function and perioperative xanthine metabolizing enzymes (XME) activity in kidney transplant recipients divided into early (EGF), slow (SGF), and delayed graft function (DGF) groups.

STUDY DESIGN

XME activity and UA levels were measured in blood samples collected directly before and during the first and fifth minutes of reperfusion.

RESULTS

Results demonstrated an increase in XO and XOR activity in all groups; however, these parameters were lower in the EGF than in the DGF group (p < 0.005; p < 0.05). XD activity increased in SGF and DGF patients (p = 0.01); nevertheless, the XD/total XOR coefficient decreased only in DGF individuals (p = 0.0007). XME sensitivity, specificity, and positive and negative predictive values in discriminating SGF/DGF from EGF were 73.3% to 78%, 54% to 62.5%, 76% to 78.6%, and 56.5%, respectively. Moreover, mixed model analysis revealed that recipients classified according to results of XOR(5) and XO(5) significantly differ in 1-year post-transplant allograft function (p = 0.04 and p = 0.02, respectively), but not in the frequency of acute rejection episodes (p = 0.66 and p = 0.90, respectively).

CONCLUSIONS

During renal transplantation, significant changes in XME occur that are associated with early post-transplant graft function and have potential value to discern between EGF and SGF/DGF.

Biological modulation of renal ischemia-reperfusion injury

PURPOSE OF REVIEW

Biological modulation of renal ischemia-reperfusion injury holds the potential to reduce the incidence of early graft dysfunction and to safely expand the donor pool with kidneys that have suffered prolonged ischemic injury before organ recovery.

RECENT FINDINGS

In the current review, we will discuss clinical studies that compare kidney transplant recipients with and without early graft dysfunction in order to elucidate the pathophysiology of ischemic acute allograft injury. We will specifically review the mechanisms leading to depression of the glomerular filtration rate and activation of the innate immune system in response to tissue injury.

SUMMARY

We conclude that the pathophysiology of delayed graft function after kidney transplantation is complex and shares broad similarity with rodent models of ischemic acute kidney injury. Given the lack of specific therapies to prevent delayed graft function in transplant recipients, comprehensive efforts should be initiated to translate the promising findings obtained in small animal models into clinical interventions that attenuate ischemic acute kidney injury after transplantation.

Lipoxygenase-derived hydroxyeicosatetraenoic acids--novel perioperative markers of early post-transplant allograft function?

BACKGROUND

Active metabolites of arachidonic acid (AA), eicosanoids, strongly influence renal homeostasis. The aims of this study were to measure perioperative variations in lipoxygenase (LOX)-derived 5-, 12- and 15-hydroxyeicosatetraenoic (HETE) acids levels, and to examine whether (i) dynamics of these eicosanoid generation changes during the first 5 min of renal allograft reperfusion, (ii) examined HETE acids may influence perioperative 20-HETE generation, and (iii) LOX HETE may serve as perioperative markers of early post-transplant allograft function.

METHODS

Sixty-nine kidney recipients were divided into early, slow and delayed graft function (EGF, SGF and DGF, respectively) groups. Blood was taken directly before, and in the consecutive minutes of graft reperfusion. HETE concentrations were measured using liquid chromatography. Creatinine levels were measured during the perioperative period, as well as during follow-up visits (first post-transplant year).

RESULTS

Our results demonstrated significant differences in the concentrations and dynamics of HETE changes between the examined groups. Moreover, observed changes in HETE concentrations were strongly associated with post-transplant graft function and perioperative 20-HETE synthesis. Application of cut-off limits for newly introduced markers, that is 71.72 ng/mL for 5-HETE(5), 12.3 ng/mL for 12-HETE△(5-0) and -6.1 ng/mL for 15-HETE△(5-0), resulted in 72.5-81.5% sensitivity and 50-54% specificity for SGF/DGF prediction. Moreover, mixed model analysis revealed that recipients classified according to results of 5-HETE(5) and 15-HETE△(5-0) significantly differ in 1-year post-transplant allograft function (P  =  0.03 and P  < 0.05, respectively), however, not in the frequency of acute rejections' episodes (P = 0.91 and P = 0.31, respectively).

CONCLUSION

We hereby report that human kidney transplantations are accompanied by significant changes in LOX AA metabolism, which strongly influences and predicts early (1 year) post-transplant graft function.

Lack of association of polymorphisms 239+34A/C in the SOD1 gene and 47C/T in the SOD2 gene with delayed graft function and acute and chronic rejection of kidney allografts

The superoxide dismutases (SODs) seem to be the most important enzymes involved in defense against reactive oxygen species, in particular against superoxide anion radicals. We hypothesized that genetic variability of antioxidant enzymes may have a role in development of these complications. The objective of the present study was to examine the association between polymorphisms 239+34A/C in the SOD1 gene or 47C/T in the SOD2 gene and development of delayed graft function (DGF) and acute or chronic rejection. The study included 187 recipients of first renal transplants. Patient history was analyzed taking into account DGF, acute rejection episodes, and chronic rejection. The polymorphisms were analyzed using the polymerase chain reaction-restriction fragment length polymorphism method. There were no significant associations between the polymorphisms and DGF or acute or chronic rejection. Our findings suggest that polymorphisms in SOD1 and SOD2 are not associated with development of either DGF or acute or chronic rejection.

Dynamics of thromboxane level changes during early phase of allograft reperfusion

BACKGROUND

Thromboxane (Tx) is a metabolite of arachidonic acid, which exerts a significant influence on kidney homeostasis, and may be involved in the pathogenesis of allograft rejection. The aim of this study was to: examine the dynamics of TxB2 changes during early phase of kidney allograft reperfusion, and analyze whether the observed changes in the concentrations and direction of TxB2 changes, are associated with post-transplant graft function.

METHODS

Sixty-nine transplant recipients were divided into early, slow and delayed graft function group. Blood samples were collected directly before and during first the five minutes of allograft reperfusion. TxB2 concentrations were measured using ELISA. Creatinine and GFR levels were measured on the first, fifth, and 10th post-transplant day.

RESULTS

The results demonstrated that during reperfusion significant differences in TxB2 concentrations occur in all groups. Moreover, significant differences in the concentrations, as well as in the dynamics of TxB2 changes between patients with immediate graft function, and individuals with allograft activation problems, were noticed. These differences were associated with post-transplant graft function.

CONCLUSIONS

Human renal transplantations are accompanied by changes in TxB2 concentrations, and the dynamics of TxB2 changes is associated with early post-transplant graft function. Our results also highlight TxB2 as a potential pre-transplant marker of post-transplant allograft function.

Gene expression patterns in deceased donor kidneys developing delayed graft function after kidney transplantation

BACKGROUND

Delayed graft function (DGF) after kidney transplantation (KTx) ranges between 2% and 50%. The mechanisms leading to DGF deserve special interest because DGF exerts negative influences on long-term outcomes. We studied gene expression profiles in deceased donor kidney (DDK) biopsies with and without DGF.

METHODS

Gene expression profiling was performed on donor kidney tissues from 33 DDK with the use of microarrays. DDK were classified as grafts with immediate function (non-DGF; n=21) and grafts with DGF (n=12). DGF was defined as a dialysis requirement in the first week after transplantation. Demographic donor and recipient information was collected. The robust-multiarray average method was used to estimate probe set expression summaries. Logistic regression was used to identify genes significantly associated with DGF development.

RESULTS

Patients were followed for 3 months after KTx. Thirty-eight probe sets (n=36 genes) were univariably differentially expressed in DDK with DGF when compared with DDK with non-DGF (alpha=0.001). Sixty-nine probe sets (n=65 genes) were differentially expressed in DDK with DGF when compared with DDK with non-DGF after adjusting for cold ischemia time (alpha=0.001). Gene ontology terms classified the overexpressed genes in DDK with DGF as principally related to cell cycle/growth (e.g., IGFBP5, CSNK2A2), signal transduction (e.g., RASGRP3), immune response (e.g., CD83, BCL3, MX1), and metabolism (e.g., ENPP4, GBA3). TNFRSF1B was overexpressed in DDK with DGF.

CONCLUSIONS

Cold ischemia time was a predictor of DGF independently of the preservation method. We identified a set of 36 genes candidates of DGF in DDK, with genes involved in the inflammatory response being the more important.

Resveratrol Attenuates Ischemia - Reperfusion-Induced Leukocyte - Endothelial Cell Adhesive Interactions and Prolongs Allograft Survival Across the MHC Barrier

BACKGROUND

Ischemic - reperfusion (IR) injury is a multifactorial process that leads to tissue damage and rejection in composite tissue allotransplantation (CTA). Antioxidant or free radical scavenger may reduce IR injury, so the effects of resveratrol, a natural antioxidant, on amelioration of leukocyte - endothelial cell adhesive interaction and prevention of transplant rejection in CTA were investigated.

METHODS AND RESULTS

In a microcirculatory study, resveratrol significantly reduced the number of IR-induced leukocytes rolling, adhering, and transmigrating in the postcapillary venules of the cremaster muscle. In the CTA study using groin skin flap allotransplantation across the MHC barrier 8-11-week-old Brown Norway donors (RT1(n)) and 10-11-week-old Lewis recipients (RT1(l)) rats were randomized into 4 groups: isograft control, allograft control, and 2 groups that received different doses of resveratrol (0.1 or 0.5 mg/kg) for 7 days. Allograft control animals rejected their allograft between 5 and 7 days postoperatively, whereas resveratrol-treated recipients had a moderate survival prolongation compared with the allograft control group. Consistent with these observations, histology results also showed reduction of lymphocytic infiltration and necrosis in resveratrol-treated subjects.

CONCLUSION

Resveratrol treatment prolonged groin skin flap allotransplant survival in the recipient and ameliorated the leukocyte - endothelial cell adhesive interactions that may lead to attenuated and delayed rejection in CTA.