Relationship between GFR, intact PTH, oxidized PTH, non-oxidized PTH as well as FGF23 in patients with CKD

Fibroblast growth factor 23 (FGF23) and parathyroid hormone (PTH) are regulators of renal phosphate excretion and vitamin D metabolism. In chronic kidney disease (CKD), circulating FGF23 and PTH concentrations progressively increase as renal function declines. Oxidation of PTH at two methionine residues (positions 8 and 18) causes a loss of function. The impact of n-oxPTH and oxPTH on FGF23 synthesis, however, and how n-oxPTH and oxPTH concentrations are affected by CKD, is yet unknown. The effects of oxidized and non-oxidized PTH 1-34 on Fgf23 gene expression were analyzed in UMR106 osteoblast-like cells. Furthermore, we investigated the relationship between n-oxPTH and oxPTH, respectively, with FGF23 in two independent patients' cohorts (620 children with CKD and 600 kidney transplant recipients). While n-oxPTH stimulated Fgf23 mRNA synthesis in vitro, oxidation of PTH in particular at Met8 led to a markedly weaker stimulation of Fgf23. The effect was even stronger when both Met8 and Met18 were oxidized. In both clinical cohorts, n-oxPTH-but not oxPTH-was significantly associated with FGF23 concentrations, independent of known confounding factors. Moreover, with progressive deterioration of kidney function, intact PTH (iPTH) and oxPTH increased substantially, whereas n-oxPTH increased only moderately. In conclusion, n-oxPTH, but not oxPTH, stimulates Fgf23 gene expression. The increase in PTH with decreasing GFR is mainly due to an increase in oxPTH in more advanced stages of CKD.

Sulforaphane and Vitamin E Protect From Glucotoxic Neurodegeneration and Lifespan Reduction In C. Elegans

Caenorhabditis elegans is an established model organism in neurodegeneration and aging research. Oxidative stress and formation of advanced glycation endproducts (AGEs), as they occur under hyperglycemic conditions in diabetes mellitus, contribute to neuronal damage and lifespan reduction. Sulforaphane (SFN) is an indirect antioxidant, alpha-tocopherol (vitamin E) is a direct antioxidant that acts as a free radical scavenger. Aim of this study is to investigate the protective effects of SFN and vitamin E against glucotoxic damages to the neuronal system and lifespan in C. elegans. Culture conditions that mimic clinical hyperglycemia increased the formation of reactive oxygen species (ROS) (p<0.001) and the accumulation of methylglyoxal-derived advanced glycation endproducts (MG-derived AGEs) (p<0.01) with subsequent neuronal damage and neuronal dysfunction, ultimately leading to a significant shortening of lifespan (p<0.01). Treatment with both, 20 µmol/l SFN and 200 µg/ml vitamin E, completely prevented the increase in ROS and MG-derived AGEs, abolished the glucotoxic effects on neuronal structure and function, and preserved lifespan, resulting in a life expectancy similar to untreated controls. These data emphasize the relevance of indirect and direct antioxidants as potential therapeutic options for the prevention of glucotoxic pathologies.

Being Born Large for Gestational Age is Associated with Increased Global Placental DNA Methylation

Being born small (SGA) or large for gestational age (LGA) is associated with adverse birth outcomes and metabolic diseases in later life of the offspring. It is known that aberrations in growth during gestation are related to altered placental function. Placental function is regulated by epigenetic mechanisms such as DNA methylation. Several studies in recent years have demonstrated associations between altered patterns of DNA methylation and adverse birth outcomes. However, larger studies that reliably investigated global DNA methylation are lacking. The aim of this study was to characterize global placental DNA methylation in relationship to size for gestational age. Global DNA methylation was assessed in 1023 placental samples by LC-MS/MS. LGA offspring displayed significantly higher global placental DNA methylation compared to appropriate for gestational age (AGA; p < 0.001). ANCOVA analyses adjusted for known factors impacting on DNA methylation demonstrated an independent association between placental global DNA methylation and LGA births (p < 0.001). Tertile stratification according to global placental DNA methylation levels revealed a significantly higher frequency of LGA births in the third tertile. Furthermore, a multiple logistic regression analysis corrected for known factors influencing birth weight highlighted an independent positive association between global placental DNA methylation and the frequency of LGA births (p = 0.001).

Size matters: observations regarding the sonographic double contour sign in different joint sizes in acute gouty arthritis

OBJECTIVE

In distinguishing urate arthritis (UA) from non-crystal-related arthritides, joint sonography including the detection of the double contour sign (DCS) and hypervascularization using power Doppler ultrasound (PDUS) is an important step in the diagnostic process. But are these sonographic features equally reliable in every accessible joint under real-life conditions?

METHODS

We retrospectively analyzed 362 patients with acute arthritis and evaluated the DCS and the degree of PDUS hypervascularization in patients with gout and in those with arthritis other than urate arthritis (non-UA). We classified all joints into the groups small, medium, and large. Sensitivities, specificities, positive and negative predictive values (PPV/NPV), and a binary regression model were calculated. We also evaluated the influence of serum uric acid levels (SUA) on the presence of a DCS in each joint category.

RESULTS

Sensitivity of the DCS in gout was 72.5% in the entire cohort, 66.0% in large, 78.8% in medium, and 72.3% in small joints. In wrist joints the DCS sensitivity maxed at 83.3%, with a specificity of 81.8%. The lowest rates of DCS sensitivity were found in gout patients with elbow joint involvement (42.9%). In all joints except metatarsophalangeal joint 1 (MTP-1), the incidence of a DCS increased by the increment of SUA levels above 7.5 mg/dl (p < 0.001). PDUS signals were most commonly found in medium and small joints and were only scarce in large joints, independent of the underlying diagnosis.

CONCLUSIONS

In our study we detected different rates of accuracy regarding DCS and PDUS in patients with acute arthritis. The best results were seen in medium-size joints, especially wrists.

[Update on Diabetic Nephropathy 2018]

UPDATE ON DIABETIC NEPHROPATHY 2018:  The prevalance of elevated albuminuria in patients with diabetes is decreasing, while that of reduced eGFR is increasing, probably owing to more stringent blood pressure and blood glucose control.Well validated online score calculators for risk for renal replacement therapy, cardiovascular events and death are available online.Clinical variables remain more suited than histology for predicting end stage renal disease. Extracapillary hypercellularity, segmental sclerosis and exsudative lesions could represent a distinct risk phenotype.SGLT-2-inhibitors and GLP-1 analogues provide significant reductions of micro- and macrovascular end points. SGLT-2-inhibitors can only be prescribed at eGFR > 60 ml/min/1,73 m², GLP-1 analogues and metformin at eGFR > 30 ml/min/1,73 m².The ACC/AHA guideline 2017 defines arterial hypertension at blood pressure ≥ 130/80 mmHg, the ESC/ESH guideline 2018 at ≥ 140/90 mmHg. The blood pressure goal for patients with diabetes is < 130/80 mmHg, if well tolerated. ESC/ESH 2018 recommend not lowering blood pressure lower than 120/70 mmHg, in persons aged ≥ 65 years, systolic blood pressure 130 - < 140 mmHg is recommended.

Identification of a urine metabolite constellation characteristic for kidney allograft rejection

INTRODUCTION

Allograft rejection is still an important complication after kidney transplantation. Currently, monitoring of these patients mostly relies on the measurement of serum creatinine and clinical evaluation. The gold standard for diagnosing allograft rejection, i.e. performing a renal biopsy is invasive and expensive. So far no adequate biomarkers are available for routine use.

OBJECTIVES

We aimed to develop a urine metabolite constellation that is characteristic for acute renal allograft rejection.

METHODS

NMR-Spectroscopy was applied to a training cohort of transplant recipients with and without acute rejection.

RESULTS

We obtained a metabolite constellation of four metabolites that shows promising performance to detect renal allograft rejection in the cohorts used (AUC of 0.72 and 0.74, respectively).

CONCLUSION

A metabolite constellation was defined with the potential for further development of an in-vitro diagnostic test that can support physicians in their clinical assessment of a kidney transplant patient.

Neuro-Endocrine Recovery After Pituitary Apoplexy: Prolactin as a Predictive Factor

Objective Pituitary apoplexy is a serious medical complication of a pre-existing pituitary adenoma characterized by a variety of clinical symptoms ranging from mild headache to neurologically impaired and finally comatose patients. Management options are surgery or conservative treatment (e. g., with dexamethasone). Surgery is commonly performed in case of severe acute neurological and visual symptoms. However, prospective studies demonstrating a benefit of surgery over conservative treatment in terms of visual, neurological and even endocrine outcomes are lacking. Decision making is still controversial, and recommendations for surgery are based on low evidence grades and focus on visual impairment. Endocrine function and especially markers identifying patients with potential for pituitary recovery after surgery are not well described in the literature.

Patients and Design We analysed data from 24 patients (m:f/16:8) with a median age of 64 yrs (38 to 83yrs) that underwent surgery for pituitary apoplexy regardless of time from symptom onset. Apoplexies were necrotic in 14 cases and haemorrhagic in 10 cases.

Results Preoperatively, 7 patients (29.2%) showed complete anterior pituitary insufficiency, 16 patients (66.6%) had partial anterior pituitary insufficiency and one patient (4.17%) had normal pituitary functions. Persistent panhypopituitarism was found in 7 patients (29.2%), whereas an overall improvement of pituitary function was noted in 13 (57.1%) patients. Preoperative prolactin (PRL) levels were significantly associated with recovery of endocrine functions, whereas specifically all patients with preoperative PRL levels of at least 8.8 ng/ml recovered partially or fully. Time to surgery (0–7 days vs. 1–4 weeks vs.>4 weeks) was not significantly associated with outcome.

Conclusions Our data emphasize that normal and high preoperative PRL levels are associated with better endocrine outcome after surgery. We conclude that patients benefit from surgical intervention even after delayed diagnosis with the serum PRL levels is being a valid biomarker for clinical decision making.

Impact of spontaneous donor hypothermia on graft outcomes after kidney transplantation

A previous donor intervention trial found that therapeutic hypothermia reduced delayed graft function (DGF) after kidney transplantation. This retrospective cohort study nested in the randomized dopamine trial (ClinicalTrials.gov identifier: NCT000115115) investigates the effects of spontaneous donor hypothermia (core body temperature <36°C) on initial kidney graft function, and evaluates 5-year graft survival. Hypothermia assessed by a singular measurement in the intensive care unit 4-20 hours before procurement was associated with less DGF after kidney transplantation (odds ratio [OR] 0.56, 95% confidence interval [CI] 0.34-0.91). The benefit was greater when need for more than a single posttransplant dialysis session was analyzed (OR 0.48, 95%CI 0.28-0.82). Donor dopamine ameliorated dialysis requirement independently from hypothermia in a temporal relationship with exposure (OR 0.93, 95%CI 0.87-0.98, per hour). A lower core body temperature in the donor was associated with lower serum creatinine levels before procurement, which may reflect lower systemic inflammation and attenuated renal injury from brain death. Despite a considerable effect on DGF, our study failed to demonstrate a graft survival advantage (hazard ratio [HR] 0.83, 95%CI 0.54-1.27), whereas dopamine treatment was associated with improved long-term outcome (HR 0.95, 95%CI 0.91-0.99 per hour).

Renal Transplantation in HIV-positive Renal Transplant Recipients: Experience at the Mannheim University Hospital

Renal transplantation in HIV-positive patients with end-stage renal disease has in recent years become a successful treatment option. We report two patients who underwent renal transplantation using a combination of basiliximab, calcineurin inhibitors, mycophenolate mofetil (MMF), and steroids with a "non-interacting" antiretroviral combination therapy consisting of stavudine or abacavir, lamivudine, and nevirapine. We observed no acute rejection but a BK polyomavirus infection in both patients. In conclusion, a quadruple immunosuppression with an interleukin 2 receptor antagonist, a calcineurin inhibitor, MMF, and steroids appears to be advisable to prevent high rates of acute rejection, but if possible thereafter immunosuppression should be tapered rapidly (eg, MMF stop, prednisolone dose 5 mg/d). The selection of antiretroviral agents should avoid compounds that interact severely with the immunosuppression used.

Association between apolipoprotein A-IV concentrations and chronic kidney disease in two large population-based cohorts: results from the KORA studies

BACKGROUND

Apolipoprotein A-IV (apoA-IV) is an anti-atherogenic and antioxidative glycoprotein. Plasma apoA-IV levels are elevated in patients with primary chronic kidney disease (CKD) or renal failure. The association between apoA-IV and kidney function has not been investigated in the general population; therefore, we analysed this relationship in two large population-based cohorts.

METHODS

Plasma apoA-IV concentrations were measured in the Cooperative Health Research in the Region of Augsburg (KORA) F3 (n = 3159) and KORA F4 (n = 3061) studies. CKD was defined by the serum creatinine-estimated glomerular filtration rate (eGFR) and/or urine albumin-to-creatinine ratio.

RESULTS

Mean (±SD) apoA-IV concentration was 17.3 ± 4.7 mg dL(-1) in KORA F3 and 15.3 ± 4.3 mg dL(-1) in KORA F4. Fully adjusted linear mixed models revealed a significant association between apoA-IV concentration and lower eGFR in the third and fourth versus the first quartile of apoA-IV (β = -1.78 mL min(-1) /1.73 m², P = 0.0003 and β = -5.09 mL min(-1) /1.73 m², P = 2.83 × 10(-23) , respectively). ApoA-IV was significantly associated with an eGFR of <60 mL min(-1) /1.73 m², which was observed in 601 of the 6220 study participants [odds ratio (OR) 1.46, P = 0.03 and OR 3.47, P = 6.84 × 10(-15) for the third and fourth vs. the first quartile of apoA-IV, respectively]. Adding apoA-IV (fourth vs. first quartile) to the fully adjusted model significantly improved discrimination of eGFR <60 mL min(-1) /1.73 m² in KORA F3 [integrated discrimination improvement (IDI) 0.03, P = 1.30 × 10(-7) ] and KORA F4 (IDI 0.04, P = 1.32 × 10(-9) ) beyond classical risk factors for CKD.

CONCLUSION

The present analysis in two population-based cohorts revealed that high plasma apoA-IV concentrations are strongly associated with low kidney function defined by eGFR independent of major CKD risk factors. ApoA-IV appears to be an early marker of impaired kidney function.

Anticoagulation in patients with impaired renal function and with haemodialysis. Anticoagulant effects, efficacy, safety, therapeutic options

Patients with impaired renal function are exposed to an increased risk for bleeding complications depending on the amount of the anticoagulant eliminated by the kidneys. The elimination of unfractionated heparins, vitamin K antagonists and argatroban is only minimally influenced by a reduced renal function. Low-molecular weight heparins, fondaparinux, danaparoid, hirudins and non-vitamin K antagonist oral anticoagulants (NOAC) cause a variably increased bleeding risk in renal impairment. Dose reductions are recommended for all of these anticoagulants in renal impairment, some are even contraindicated at certain levels of renal impairment. Their benefit over the conventional anticoagulants is preserved if renal dosing is employed. For end-stage renal disease patients specific treatment regimens are required.

Carnosine treatment in combination with ACE inhibition in diabetic rats

In humans, we reported an association of a certain allele of carnosinase gene with reduced carnosinase activity and absence of nephropathy in diabetic patients. CN1 degrades histidine dipeptides such as carnosine and anserine. Further, we and others showed that treatment with carnosine improves renal function and wound healing in diabetic mice and rats. We now investigated the effects of carnosine treatment alone and in combination with ACE inhibition, a clinically established nephroprotective drug in diabetic nephropathy. Male Sprague-Dawley rats were injected i.v. with streptozotocin (STZ) to induce diabetes. After 4 weeks, rats were unilaterally nephrectomized and randomized for 24 weeks of treatment with carnosine, lisinopril or both. Renal CN1 protein concentrations were increased under diabetic conditions which correlated with decreased anserine levels. Carnosine treatment normalized CN1 abundance and reduced glucosuria, blood concentrations of glycosylated hemoglobin (HbA1c), carboxyl-methyl lysine (CML), N-acetylglucosamine (GlcNac; all p<0.05 vs. non-treated STZ rats), reduced cataract formation (p<0.05) and urinary albumin excretion (p<0.05), preserved podocyte number (p<0.05) and normalized the increased renal tissue CN1 protein concentration. Treatment with lisinopril had no effect on HbA1C, glucosuria, cataract formation and CN1 concentration, but reduced albumin excretion rate more effectively than carnosine treatment (p<0.05). Treatment with both carnosine and lisinopril combined the effects of single treatment, albeit without additive effect on podocyte number or albuminuria. Increased CN1 amount resulted in decreased anserine levels in the kidney. Both carnosine and lisinopril exert distinct beneficial effects in a standard model of diabetic nephropathy. Both drugs administered together combine the respective effects of single treatment, albeit without exerting additive nephroprotection.

Different design of enzyme-triggered CO-releasing molecules (ET-CORMs) reveals quantitative differences in biological activities in terms of toxicity and inflammation

Acyloxydiene–Fe(CO)₃ complexes can act as enzyme-triggered CO-releasing molecules (ET-CORMs). Their biological activity strongly depends on the mother compound from which they are derived, i.e. cyclohexenone or cyclohexanedione, and on the position of the ester functionality they harbour. The present study addresses if the latter characteristic affects CO release, if cytotoxicity of ET-CORMs is mediated through iron release or inhibition of cell respiration and to what extent cyclohexenone and cyclohexanedione derived ET-CORMs differ in their ability to counteract TNF-α mediated inflammation. Irrespective of the formulation (DMSO or cyclodextrin), toxicity in HUVEC was significantly higher for ET-CORMs bearing the ester functionality at the outer (rac-4), as compared to the inner (rac-1) position of the cyclohexenone moiety. This was paralleled by an increased CO release from the former ET-CORM. Toxicity was not mediated via iron as EC₅₀ values for rac-4 were significantly lower than for FeCl₂ or FeCl₃ and were not influenced by iron chelation. ATP depletion preceded toxicity suggesting impaired cell respiration as putative cause for cell death. In long-term HUVEC cultures inhibition of VCAM-1 expression by rac-1 waned in time, while for the cyclohexanedione derived rac-8 inhibition seems to increase. NFκB was inhibited by both rac-1 and rac-8 independent of IκBα degradation. Both ET-CORMs activated Nrf-2 and consequently induced the expression of HO-1.

This study further provides a rational framework for designing acyloxydiene–Fe(CO)₃ complexes as ET-CORMs with differential CO release and biological activities. We also provide a better understanding of how these complexes affect cell-biology in mechanistic terms.

Enzyme-triggered CO-releasing molecules (ET-CORMs): evaluation of biological activity in relation to their structure

Acyloxydiene-Fe(CO)3 complexes act as enzyme-triggered CO-releasing molecules (ET-CORMs) and can deliver CO intracellularly via esterase-mediated hydrolysis. The protective properties of structurally different ET-CORMs on hypothermic preservation damage and their ability to inhibit VCAM-1 expression were tested on cultured human umbilical vein endothelial cells (HUVEC) and renal proximal tubular epithelial cells (PTEC) using a structure-activity approach. Cytotoxicity of ET-CORMs, protection against hypothermic preservation damage, and inhibition of VCAM-1 expression were assessed. Cytotoxicity of 2-cyclohexenone and 1,3-cyclohexanedione-derived ET-CORMs was more pronounced in HUVEC compared to PTEC and was dependent on the position and type of the ester (acyloxy) substituent(s) (acetate>pivalate>palmitate). Protection against hypothermic preservation injury was only observed for 2-cyclohexenone-derived ET-CORMs and was not mediated by the ET-CORM decomposition product 2-cyclohexenone itself. Structural requirements for protection by these ET-CORMs were different for HUVEC and PTEC. Protection was affected by the nature of the ester functionality in both cell lines. VCAM-1 expression was inhibited by both 2-cyclohexenone- and 1,3-cyclohexanedione-derived ET-CORMs. 2-Cyclohexenone, but not 1,3-cyclohexanedione, also inhibited VCAM-1 expression. We demonstrate that structural alterations of ET-CORMs significantly affect their biological activity. Our data also indicate that different ET-CORMs behave differently in various cell types (epithelial vs endothelial). These findings warrant further studies not only to elucidate the structure-activity relation of ET-CORMs in mechanistic terms but also to assess if structural optimization will yield ET-CORMs with restricted cell specificity.

Urine of patients with acute kidney transplant rejection show high normetanephrine and decreased 2-hydroxyestrogens concentrations

BACKGROUND

A shift from anti- to proinflammatory steroid hormones has been observed in chronic inflammation. We tested the hypothesis that this shift occurs also in kidney transplant rejection together with a rise of urinary catecholamine degradation product concentrations as a consequence of locally produced cytokines, thus further promoting rejection.

METHODS

We examined 8 patients with an early rejection episode in the protocol biopsy ∼2 weeks, 9 with biopsy-proven rejection at 2-3 months, and 18 without rejection, both at 2 weeks and 3 months after transplantation. Metanephrine, normetanephrine, and 2- and 16-hydroxyestrogens concentrations were measured by EIA.

RESULTS

The median urinary concentrations of normetanephrine, but not metanephrine, were significantly higher in acute kidney transplant rejection in the first 2 weeks after transplantation (P < .05). During acute kidney transplant rejection at 2-3 months, but not in the first 2 weeks, after transplantation, 2-, but not 16-hydroxyestrogens, concentrations were significantly decreased (P < .05).

CONCLUSIONS

We demonstrated that the downstream product of noradrenaline conversion normetanephrine was elevated in kidney transplant rejection in the first weeks after transplantation. This change may promote rejection together with an important proinflammatory and mitogenic steroid hormone shift, which becomes increasingly relevant over time.

Renin, endothelial NO synthase and endothelin gene expression in the 2kidney-1clip Goldblatt model of long-term renovascular hypertension

Objective

Numerous reports have shown the influence of renin, nitric oxide (NO) and the endothelin (ET) systems for regulation of blood pressure and renal function. Furthermore, interactions between these peptides have been reported. Aim of our study was to investigate the relative contribution of these compounds in long-term renovascular hypertension/renal ischemia.

Methods

Hypertension/left-sided renal ischemia was induced using the 2K1C-Goldblatt rat model. Renal renin, ET-1, ET-3 and endothelial NO synthase (eNOS) gene expression was measured by means of RNAse protection assay at different timepoints up to 10 weeks after induction of renal artery stenosis.

Results

Plasma renin activity and renal renin gene expression in the left kidney were increased in the clipped animals while eNOS expression was unchanged. Furthermore, an increase in ET-1 expression and a decrease of ET-3 expression was detected in early stenosis.

Conclusions

While renin is obviously involved in regulation of blood pressure and renal function in unilateral renal artery stenosis, ET-1, ET-3 and endothelium derived NO do not appear to play an important role in renal adaptation processes in long-term renal artery stenosis, although ET-1 and ET-3 might be involved in short-term adaptation processes.

[Expert consensus statement on interventional renal sympathetic denervation for hypertension treatment]

This commentary summarizes the expert consensus and recommendations of the working group 'Herz und Niere' of the German Society of Cardiology (DGK), the German Society of Nephrology (DGfN) and the German Hypertension League (DHL) on renal denervation for antihypertensive treatment. Renal denervation is a new, interventional approach to selectively denervate renal afferent and efferent sympathetic fibers. Renal denervation has been demonstrated to reduce office systolic and diastolic blood pressure in patients with resistant hypertension, defined as systolic office blood pressure ≥ 160 mm Hg and ≥ 150 mm Hg in patients with diabetes type 2, which should currently be used as blood pressure thresholds for undergoing the procedure. Exclusion of secondary hypertension causes and optimized antihypertensive drug treatment is mandatory in every patient with resistant hypertension. In order to exclude pseudoresistance, 24-hour blood pressure measurements should be performed. Preserved renal function was an inclusion criterion in the Symplicity studies, therefore, renal denervation should be only considered in patients with a glomerular filtration rate > 45 ml/min. Adequate centre qualification in both, treatment of hypertension and interventional expertise are essential to ensure correct patient selection and procedural safety. Long-term follow-up after renal denervation and participation in the German Renal Denervation (GREAT) Registry are recommended to assess safety and efficacy after renal denervation over time.

FOXP3+ regulatory T-cells in renal allografts: correlation with long-term graft function and acute rejection

BACKGROUND

The interpretation of a cellular infiltrate as cytotoxic or tolerogen represents an unsolved challenge in current transplantation. The so-called regulatory CD4+ CD25+ T-cells which express the FOXP3 gene have received increasing interest with respect to this question. The existing studies concerning the role of FOXP3+ Tregs for transplant tolerance yielded contradictory results.

METHODS

We examined the numbers of the FOXP3+ Tregs in two groups of renal allograft biopsies both showing cellular infiltration, but either without (n=29) or with signs of acute cellular rejection (n=26), by means of immunofluorescence and correlated the amount of FOXP3+ Tregs to renal function at the time of biopsy and after 1 and 2 years of follow up.

RESULTS

The number of FOXP3+ Tregs within infiltrates in non-rejecting biopsies did not correlate with renal function after 1 and 2 years. There were no significant differences in the numbers of FOXP3+ Tregs between biopsies with or without borderline infiltrates. Increased numbers of FOXP3+ Tregs were not associated with an ameliorated severity of graft rejection and did not correlate with outcome after the rejection episode and renal function after 1 and 2 years.

CONCLUSIONS

The identification of the FOXP3+ regulatory cells within the allograft cannot be considered as an appropriate marker for the interpretation of infiltrates as cytotoxic or tolerogenic or as a prognostic marker for later transplant function.

Tacrolimus once daily (ADVAGRAF) versus twice daily (PROGRAF) in de novo renal transplantation: a randomized phase III study

This multicenter, 1:1-randomized, parallel-group, noninferiority study compared the efficacy and safety of twice-daily tacrolimus (Tacrolimus BID; Prograf) and once-daily tacrolimus prolonged release (Tacrolimus QD; Advagraf), combined with steroids and low-dose mycophenolate mofetil without antibody induction, in 667 de novo kidney transplant recipients. A double-blind, double-dummy 24-week period was followed by an open extension of up to 12 months posttransplant. Biopsy-proven acute rejection rate at 24 weeks (primary endpoint, per-protocol analysis) was 15.8% for Tacrolimus BID versus 20.4% for Tacrolimus QD (p = 0.182; treatment difference 4.5%, 95% confidence interval-1.8%, 10.9%, just outside the prespecified 10% noninferiority margin). Kaplan-Meier 12-month patient and graft survival rates were 97.5% and 92.8% for Tacrolimus BID and 96.9% and 91.5% for QD. Both treatment groups showed equally well-maintained renal function at 12 months (mean creatinine clearance approximately 67 mL/min) and similar adverse event profiles. Overall results obtained with either Tacrolimus QD or BID, without antibody induction, were good, supporting use of the once-daily formulation as an effective alternative to the established twice-daily formulation.

Tacrolimus once daily (ADVAGRAF) versus twice daily (PROGRAF) in de novo renal transplantation: a randomized phase III study

This multicenter, 1:1-randomized, parallel-group, noninferiority study compared the efficacy and safety of twice-daily tacrolimus (Tacrolimus BID; Prograf) and once-daily tacrolimus prolonged release (Tacrolimus QD; Advagraf), combined with steroids and low-dose mycophenolate mofetil without antibody induction, in 667 de novo kidney transplant recipients. A double-blind, double-dummy 24-week period was followed by an open extension of up to 12 months posttransplant. Biopsy-proven acute rejection rate at 24 weeks (primary endpoint, per-protocol analysis) was 15.8% for Tacrolimus BID versus 20.4% for Tacrolimus QD (p = 0.182; treatment difference 4.5%, 95% confidence interval-1.8%, 10.9%, just outside the prespecified 10% noninferiority margin). Kaplan-Meier 12-month patient and graft survival rates were 97.5% and 92.8% for Tacrolimus BID and 96.9% and 91.5% for QD. Both treatment groups showed equally well-maintained renal function at 12 months (mean creatinine clearance approximately 67 mL/min) and similar adverse event profiles. Overall results obtained with either Tacrolimus QD or BID, without antibody induction, were good, supporting use of the once-daily formulation as an effective alternative to the established twice-daily formulation.

Pharmacokinetics for once- versus twice-daily tacrolimus formulations in de novo kidney transplantation: a randomized, open-label trial

Tacrolimus, a cornerstone immunosuppressant, is widely available as a twice-daily formulation (Tacrolimus BID). A once-daily prolonged-release formulation (Tacrolimus QD) has been developed that may improve adherence and impart long-lasting graft protection. This study compared the pharmacokinetics (PK) of tacrolimus in de novo kidney transplant patients treated with Tacrolimus QD or Tacrolimus BID. A 6-week, open-label, randomized comparative study was conducted in centers in Europe and Australia. Eligible patients received Tacrolimus QD or Tacrolimus BID. PK profiles were obtained following the first tacrolimus dose (day 1), and twice under steady-state conditions. As secondary objectives, efficacy and safety parameters were also evaluated. Sixty-six patients completed all PK profiles (34 Tacrolimus QD, 32 Tacrolimus BID). Mean AUC(0-24) of tacrolimus on day 1 was approximately 30% lower for Tacrolimus QD than Tacrolimus BID (232 and 361 ng.h/mL, respectively), but was comparable by day 4. There was a good correlation and a similar relationship between AUC(0-24) and C(min) for both formulations. Efficacy and safety data were also comparable over the 6-week period. Tacrolimus QD can be administered once daily in the morning on the basis of the same systemic exposure and therapeutic drug monitoring concept as Tacrolimus BID.

Percutaneous transluminal angioplasty as first-line treatment of transplant renal artery stenosis

BACKGROUND

Transplant renal artery stenosis (TRAS) is a frequent complication after renal transplantation, however long-term follow-up data after interventional treatment are rare.

PATIENTS

In our transplant center 11 of 264 consecutive renal transplant recipients (4.17%) were diagnosed with TRAS. In addition, TRAS occurred in 2 renal transplant recipients that had been transplanted at other centers but who had their follow-up examinations in our center. Either a rise of the serum creatinine level and/or worsened systemic hypertension or routine examination with color Doppler sonography were indications for further diagnostic workup.

METHODS

Direct angiography of the transplant renal artery was performed followed by percutaneous transluminal angioplasty (PTA) after the diagnosis of TRAS was confirmed in all of these patients.

RESULTS

The immediate success rate for PTA was 92.3% (12/13). Only 1 patient with a severe kinking of the transplant renal artery had to undergo surgery to restore renal function. No complications occurred after the interventions. Thereafter the patients were monitored for a mean observation period of 33.15 months. Serum creatinine levels were significantly lower after the intervention, and estimated glomerular filtration rate (eGFR) increased accordingly. With regard to blood pressure there was only a trend for lower blood pressure levels and less antihypertensive use, whereas the dose of the prescribed drugs decreased significantly with time after interventional treatment of TRAS. In addition, a long-lasting rise of the hemoglobin levels could also be demonstrated.

CONCLUSION

In summary, the beneficial effect of PTA of TRAS on renal function is long-lasting. Therefore, PTA, usually combined with stent placement, should be first-line treatment in TRAS in all patients. Surgical revascularization is only warranted, if PTA fails.

Upregulation of TNF receptor type 2 in human and experimental renal allograft rejection

An important role of TNF interacting with TNFR2 has been shown in different models of ischemic, nephrotoxic and immune-mediated renal injury. To systematically evaluate the expression of TNFR2 in renal allograft rejection, we investigated human renal allograft biopsies and, in addition, established an experimental transplantation model in rats to verify the human data under standardized conditions. The expression of TNFR2 was analyzed in 96 human renal allograft biopsies with different disease entities. In a 6-day and a 28-day experimental protocol, TNFR2 was examined in kidney specimens and in the urine of control, uni-nephrectomized and transplanted rats +/- cyclosporine treatment (n = 114). In human biopsies and in rat allografts on day 6 with acute allograft rejection, significantly elevated expression of TNFR2 was observed in tubular epithelial cells, podocytes, B cells and monocytes/macrophages. The expression level was associated with renal function. The TNFR2 expression level at day 28 was significantly lower compared to day 6. TNFR2 is markedly upregulated both in human and experimental acute renal allograft rejection. Our data are robust and consistent between different species, suggesting a role for TNFR2 in the early course of rejection.

Severe renal vein stenosis of a kidney transplant with beneficial clinical course after successful percutaneous stenting

A 51-year-old renal transplant recipient presented with marked renal function deterioration 13 months after renal transplantation. After exclusion of ureteral obstruction, transplant artery stenosis and acute rejection, the diagnosis of a severe renal vein stenosis was made by an MR scan. After angiographic confirmation of the stenosis, treatment was attempted with percutaneous stent angioplasty. The long-term clinical course was favorable, with marked improvement in renal function. Transplant renal vein stenosis is a rare, but potentially curable, cause of renal allograft functional deterioration.

[Medication-induced impairment of renal function: what is important?]

Non-steroidal antiphlogistics and COX-2 inhibitors routinely cause sodium retention and a blood pressure increase by about 5 mmHg, a decrease in renal function (by about 10 ml/min) and in 1-2% an acute renal failure. Prevention is possible by short-term, low-dose application, avoidance of dehydration, controlling serum creatinine levels 1 week after start of treatment in high-risk groups. Aminoglycosides cause acute renal failure in 10-20% which can be prevented by once daily dosing, meticulous drug monitoring. Radio contrast media cause, mostly dependent on baseline renal function, in 0-50% a radiocontrast-induced nephropathy. This can be prohibited with hydration, low volume of contrast medium, and low- (or iso)osmolar contrast medium. New preparations of vancomycin go along with a greatly reduced rate of nephrotoxicity. Drug monitoring and avoidance of a combination therapy with aminoglycosides will help to reduce toxicity. Medication-induced acute interstitial nephritis is a relevant differential diagnosis in acute renal failure: stop implicated medication, consider steroid application!

[Differential diagnosis and therapy of pulmorenal syndrome--the nephrologist's perspective]

The "pulmorenal syndrome" is a clinically defined syndrome under which one summarises disease entities with acute renal failure due to acute glomerulonephritis and alveolar lung hemorrhage. Wegener's granulomatosis, other inflammatory renal diseases and Goodpasture's syndrome are the most frequent causes of this syndrome. The physical examination and histological examination, mostly of a kidney biopsy, represent the mainstay of securing the diagnosis. The diagnosis is completed by serological testing for autoantibodies. The therapy is determined by the underlying disease. Plasmaspheresis is always performed when alveolar hemorrhage is present, and in most cases where the patient presents with the need for immediate dialysis. An immunosuppressive therapy is determined by the underlying disease.

Five-Year Follow-up After Late Conversion From Calcineurin Inhibitors to Sirolimus in Patients With Chronic Renal Allograft Dysfunction

BACKGROUND

Chronic allograft nephropathy (CAN) is, among others, caused by nephrotoxic side effects of calcineurin inhibitors (CNI), which are to date still the mainstay of immunosuppressive therapy. Sirolimus (SIR), an immunosuppressive compound without effects on glomerular perfusion, has been used in CNI-sparing immunosuppressive protocols. We report the 5-year follow-up of a prospective, controlled conversion study from CNI to SIR in patients with moderately to severely impaired renal function.

METHODS

Twelve renal transplant recipients with moderately to severely impaired renal function (estimated glomerular filtration rate of 17 to 35 mL/min according to the MDRD formula), enrolled in a prospective, controlled 1-year pilot study were followed for 5 years.

RESULTS

Three renal grafts (25%) were lost during the 5-year follow-up. Graft loss was due to noncompliance in one patient and to CAN in the other two patients. These two patients returned to dialysis 43 and 59 months after conversion, corresponding to 86 and 75 months after transplantation, respectively. Six of nine patients had a stable or even better renal function compared to the baseline. The lipid profile increased initially, but then remained stable over time.

CONCLUSION

Conversion of immunosuppressive therapy from CNI to SIR in patients with impaired renal function more than 1 year after transplantation is feasible and safe yielding improved renal function in the majority of patients, which was sustained at 5 years follow-up.

Effect of ACE and AT-2 inhibitors on mortality and progression to microalbuminuria in a nested case-control study of diabetic nephropathy in diabetes mellitus type 2: results from the GENDIAN study

INTRODUCTION

There is an established role of clinical risk factors such as arterial hypertension and smoking in causing cardiovascular morbidity and diabetic nephropathy (DNP). Genetic factors increase the risk for DNP. To examine the genetic risk, we initiated a case-control study with predefined follow-up examinations. We describe the study design and baseline characteristics under special consideration of comedication, and give preliminary results of the 4-year follow-up.

METHODS

We enrolled all 477 patients with DNP receiving maintenance hemodialysis in 30 centers in Southern Germany between August 1999 and January 2000. As controls, we enrolled all 482 diabetes mellitus type 2 patients without urinary microalbuminuria in two examinations on consecutive days and without other signs of renal disease in a large diabetes clinic from September 2000 to September 2001. Follow-up examinations are performed 4 and 6 years after inclusion by questionnaire and telephone interview to determine mortality and new morbidity. Controls progressing to novel DNP at follow-up, as defined by semiquantitative dipstick urinary albumin/creatinine ratio > 30 mg/g, are defined as cases in the study's nested case control component.

RESULTS

At study inclusion in cases and controls, respectively, mean age was 67.3 +/- 8.2 and 58.1 +/- 11.2 years and duration of diabetes mellitus was 15.6 +/- 9.6 (at dialysis initiation) and 11.0 +/- 8.6 years. 328 controls (of which 25 had died and 14 did not perform urinalysis) were subjected to follow-up at 4 years, at a mean of 3.5 +/- 0.8 years after inclusion. 51.2% (n = 148) of living controls remained normalbuminuric, 33.9% (n = 98) had microor macroalbuminuria, and in 14.9% (n = 43) the dipstick test was inconclusive. There was no significant difference in progression to micro- or macroalbuminuria between controls treated with ACE or AT-2 inhibitors at baseline or not. Renal function as estimated by the abbreviated MDRD formula declined from 86.8 +/- 21.0 to 82.5 +/- 22.3 ml/min/1.73 m2 (p < 0.001). The decline was significant in patients on ACE or AT-2 inhibitors at baseline and not in patients without such medication at baseline.

DISCUSSION

GENDIAN is a large case-control study designed to evaluate clinical and genetic determinants of DNP and other complications of long-standing diabetes mellitus type 2. We observed an association of ACE or AT-2 inhibitor therapy with cardiovascular comorbidity and a significant decline in renal function after a 4-year follow-up.

SDF-1 expression is elevated in chronic human renal allograft rejection

The exact mechanism of acute and chronic allograft rejection still remains unclear. The chemokine SDF-1 as mediator of allograft rejection has been under intensive investigation in liver, cardiac and bone marrow transplantation, whereas in renal transplantation, there are no reports about SDF-1 to date. This study was performed to evaluate if SDF-1 might also play an important role in human renal graft biopsies. One hundred and ninety formalin-fixed, paraffin-embedded renal allograft biopsies were included in the analysis from patients with normal renal graft morphology (according to Banff 97 classification grade 1, n = 84), with acute interstitial rejection (Banff grade 4 type I, n = 10), with acute vascular rejection (Banff grade 4 type II, n = 21), with chronic allograft nephropathy (CAN, Banff grade 5, n = 23), and without rejection but with various other lesions (Banff grade 6, n = 42). SDF-1 was localized by immunohistochemistry. In biopsies with CAN, SDF-1 expression was significantly elevated in interstitial infiltrates and infiltrating neointimal cells of arteries compared with biopsies with normal renal graft morphology. This is the first study describing a role of SDF-1 in human renal allograft rejection. We were able to demonstrate in a large number of biopsies an upregulation of SDF-1 in patients with CAN. Whether SDF-1 has pro-inflammatory or protective properties in this setting has to be evaluated in further trials.

Exanthema and acute anuric renal failure

A 15-year-old girl with a history of Kawasaki disease was admitted to our nephrological department due to acute renal failure. Despite antibiotic therapy because of fever and the symptoms of a pharyngitis in the last few days, the girl showed persisting fever and developed arthralgias, an exanthema and a rising serum creatinine as well as anuria. A wide variety of differential diagnoses has to be thought of because of the history of the Kawasaki disease (symptoms like fever, pharyngitis, exanthema and arthralgia), i.e. hemolytic-uremic syndrome, vasculitis, ascending infection, postinfection glomerulonephritis. In consideration of etiologically unclear "rapidly progressive renal failure" with anuria and thrombocytopenia an immediate renal biopsy was done and revealed a severe drug induced acute interstitial nephritis. Due to this diagnosis we treated the patient with corticosteroids. Within 4 weeks serum creatinine declined to 1.8 mg/dl but did not normalize.

Increase in renal vascular resistance after intake of cyclosporin A and tacrolimus and reversal by nitroglycerin spray: a study in patients with stable renal allograft function

PURPOSE

Acute effects of drug administration on renal arterial resistance index (RI) are still discussed controversially. In our study we investigated the immediate effects of cyclosporin A (CyA) and tacrolimus (FK-506) on renal arterial resistance indices in patients with stable graft function after renal transplantation. Additionally we studied the effects of nitroglycerin spray on resistance indices.

METHODS

RI was measured by color Doppler sonography at baseline, at 1 and 2 hours after intake of medication and 30 minutes after administration of nitroglycerin spray which followed the 2-hour measurement. 34 renal transplant recipients were examined. 16 patients received CyA, 18 patients received FK-506. Whole blood levels of calcineurin inhibitors were taken at each time point. Arterial blood pressure and heart rate were measured to assess possible systemic hemodynamic effects.

RESULTS

Mean RI values increased significantly in both groups 1 hour after calcineurin inhibitor intake and remained still significantly elevated after 2 hours. There was no significant increase of mean arterial blood pressure nor was there any correlation between whole blood levels of calcineurin inhibitors and mean RI. 30 minutes after administration of nitroglycerin spray, mean RI values decreased significantly to a level even below baseline. Mean arterial blood pressure also decreased after administration of nitroglycerin.

CONCLUSION

Renal RI values are markedly influenced by a recent intake of calcineurin inhibitors and vasoactive substances such as nitrates. This demonstrates the necessity of keeping standardized conditions when using RI as a tool in followup investigations after renal transplantation.

Conversion from calcineurin inhibitors to sirolimus in patients with chronic renal allograft dysfunction

BACKGROUND

Chronic renal transplant dysfunction in part may be due to the nephrotoxic effects of calcineurin inhibitors, which are still the mainstay of immunosuppressive therapy. Sirolimus, a new immunosuppressive compound devoid of significant nephrotoxicity, might therefore exhibit beneficial effects when used in renal transplant recipients with graft dysfunction.

METHODS

Twelve renal transplant recipients included in this study had all been receiving calcineurin inhibitors for more than 12 months, and were free of rejection for more than 12 months. However, they demonstrated moderate renal dysfunction with serum creatinine values ranging from 1.8 to 4.0 mg/dL (164 to 351 micromol/L). After reaching a sirolimus level of 10 to 20 ng/mL, calcineurin inhibitor therapy was withheld.

RESULTS

One month after initiation of sirolimus therapy, all patients were off calcineurin inhibitors. The average daily sirolimus dosage was 5.8+/-3.4 mg. No acute rejection episode and no graft failure was observed. No patient required hemodialysis or admission to the hospital. Calculated creatinine clearance increased from 63.4+/-9.9 to 69.2+/-9.7 mL/min (P=.0368) and serum bicarbonate increased from 20.8+/-3.17 to 22.5+/-3.7 meq/L (P=.001). Serum cholesterol increased from 180+/-26.5 to 239+/-28.8 mg/dL (4.65+/-0.69 to 6.18+/-0.74 mmol/L, P<.001), triglycerides increased from 155+/-53 to 289+/-123 mg/dL (1.75+/-0.6 to 3.26+/-1.39 mmol/L) and low-density lipoprotein cholesterol increased from 99+/-32 to 131+/-25.1 mg/dL (2.56+/-0.83 to 3.39+/-0.65 mmol/L, P=.01). Arterial blood pressure remained well controlled (126+/-15.6/74+/-8.9 vs 134+/-16.8/83+/-9.7).

CONCLUSION

Conversion from calcineurin inhibitor therapy to sirolimus in patients more than 1 year after transplantation with impaired organ function is feasible, safe, and associated with a trend toward improved renal function.

Pretransplant calcium levels have no predictive value for delayed graft function, long-term graft function, cardiovascular events, or graft and patient survival in renal transplantation

BACKGROUND

Disorders of calcium homeostasis are one of the most common problems in patients with end-stage renal disease (ESRD). Elevated calcium levels increase the incidence of cardiovascular mortality in ESRD patients, and appear to be a risk factor for the occurrence of delayed graft function (DGF) after kidney transplantation. Therefore, we investigated the impact of pretransplant serum calcium levels on outcomes after kidney transplantation: DGF, acute rejection, graft function, and survival, as well as the incidence of cardiovascular events.

METHODS

We studied 285 patients (96.9% of all transplanted patients) who underwent their first transplantation between 1995 and 2004. Demographic data were extracted from hospital records or were documented during follow-up; serum samples were collected at the time of transplantation.

RESULTS

In our cohort the incidence of DGF was 16.5% and 35.4% of acute rejection episodes (ARE). However, pretransplant calcium levels were not related to DGF or ARE in our patient cohort. Furthermore, there was no correlation between pretransplant serum calcium level with the incidence of cardiovascular events or mortality, as well as graft function or survival.

CONCLUSION

In our study population pretransplant calcium levels showed no effect on DGF, ARE rate, the occurrence of cardiovascular events or death, renal graft function, or survival. Therefore, pretransplant calcium level is not a helpful marker for risk stratification at the time of transplantation.

Mini-incision for strictly retroperitoneal nephrectomy in living kidney donation vs flank incision

BACKGROUND

Mini-incision donor nephrectomies (MIDNs) were established during the last decade, as an alternative to traditional open donor nephrectomy (ODN) via flank incision. In this study, we investigated intra-operative and post-operative data on outcome following MIDN in comparison with ODN data.

METHODS

Data of 70 living kidney donations, performed at the University of Regensburg Medical Center since 1996, were evaluated. Donor operation was performed as either strictly retroperitoneal MIDN (n = 34) or as traditional ODN (n = 36) via flank incision. Total operation time, warm ischaemia time (WIT), perioperative pain-medication usage and creatinine levels as well as length of hospital stay, return to complete enteral nutrition and regular digestion were evaluated retrospectively.

RESULTS

Total operation times were similar in MIDN, n = 34 (132 +/- 26 min) and in ODN, n = 36 (140 +/- 37 min) (P = 0.424). WIT was also similar in both: MIDN (0.9 +/- 0.4 min) and ODN (0.9 +/- 0.4 min) (P = 0.568). The requirement for post-operative opioids in morphine equivalent doses was significantly lower in MIDN (8.4 +/- 16 mg) compared with ODN (44 +/- 57 mg) (P = 0.001). Additional application of non-opioids (metamizole) (MIDN: 4.8 +/- 6.3 g, ODN: 3.4 +/- 3.9 g) and non-steroidal antirheumatic (NSAR) (diclofenac) (MIDN: 322 +/- 361 mg, ODN: 247 +/- 474 mg) revealed no significant differences between the groups. The hospital stay was 4.9 +/- 1.4 days in MIDN which was significantly shorter than that in ODN (9.3 +/- 3.3 days) (P = 0.001). Patients achieved fully independent mobility earlier in MIDN than in ODN (P = 0.934). Start of enteral nutrition with fluids was significantly quicker in MIDN (1.9 +/- 7 h) compared with ODN (12 +/- 13 h) (P = 0.05). Full enteral nutrition was accomplished significantly earlier in MIDN (1.6 +/- 0.8 days) (P = 0.023). Return to normal digestion revealed no significant differences between groups. Serum creatinine levels of all kidney donors were in the normal range (66 +/- 18 micromol/l) one day before nephrectomy, increased on day 1 after surgery (119 micromol/l +/- 31 micromol/l) and were stable on day 3 (115 micromol/l +/- 30 micromol/l) without significant differences.

CONCLUSION

Strictly, retroperitoneal MIDN in living kidney donation is a fast and safe method for the procurement of a living donor graft, giving the patient a significantly shorter period of recovery, and thus is an attractive and recommendable alternative to traditional ODN procedures.

Reverse diastolic intrarenal flow due to calcineurin inhibitor (CNI) toxicity

Renal calcineurin inhibitor (CNI) toxicity is a frequent side effect of immunosuppression with CNIs in solid organ transplantation, leading to acute and chronic renal failure. Acute CNI toxicity is due to vasoconstriction of the vasa afferens and efferens and vacuolization of smooth muscle cells with medial hyalinosis, leading to vessel lumen narrowing. Our case had an acute renal failure 8 months after deceased donor kidney transplantation under treatment with tacrolimus, sirolimus and prednisolone. In Doppler sonography, we observed reverse diastolic intrarenal blood flow, reflecting intense vessel narrowing. There were histological signs of acute CNI toxicity. Within days of reducing the tacrolimus trough level, renal function improved markedly and Doppler sonography showed orthograde intrarenal blood flow. This is the first case of functional, Doppler sonographic evidence for CNI-induced, rapidly reversible narrowing of intrarenal vessels. This case illustrates the potential role of tacrolimus and sirolimus dosing in combination therapy to produce severe intrarenal vasoconstriction.

[Treatment and prophylaxis of recurrent urinary tract infections]

Recurrent urinary tract infections are typical diseases of sexually active young women. Only elder women show significant rates of underlying, mostly urological diseases. Besides behavioral changes long-term antimicrobial therapy is still the mainstay of both prophylaxis and therapy. This report provides information on the etiology for recurrent urinary tract infections. Strategies for prevention are illustrated. The actual significances of organic remedies and antibiotics respectively are discussed; ineffective therapies are identified. Furthermore an outlook is given on promising novel therapeutics, i.e. vaccines which are already tested in clinical trials.

Steroid Withdrawal or Steroid Avoidance in Renal Transplant Recipients: Focus on Tacrolimus-Based Immunosuppressive Regimens

Steroid-induced adverse effects after transplantation include cosmetic, metabolic, and cardiovascular complications. Steroid withdrawal or avoidance with cyclosporine-based regimens have been hampered by an unacceptably high rate of acute rejections and increased rates of graft loss. Recently the results of several large, randomized trials of steroid withdrawal/avoidance with tacrolimus-based immunosuppression in renal transplant recipients became available. A review of these trials appeared to be of clinical interest. Data from the THOMAS trial clearly indicate that steroid withdrawal from a regimen of tacrolimus, mycophenolate mofetil (MMF), steroids after 3 months after transplantation is safe with regard to acute rejection rate and graft survival. If an induction therapy with daclizumab is used in combination with tacrolimus and MMF (CARMEN trial), even steroid avoidance is safe with regard to acute rejection rate and graft survival. Finally, in the ATLAS trial, steroid avoidance with basiliximab in combination with tacrolimus (resulting in tacrolimus monotherapy) or alternatively with tacrolimus and MMF both resulted in similar graft survival, but higher rates of acute rejection. In conclusion, steroid withdrawal is safe from a triple-drug regimen of tacrolimus, MMF, and steroids after 3 months after transplantation, and steroid use may completely be avoided with tacrolimus, and MMF combined with daclizumab induction. Tacrolimus monotherapy may be achieved using basiliximab induction at the price of higher rates of acute rejection, but with unaffected graft survival. Thus tacrolimus-based immunosuppression with or without interleukin-2 receptor antagonist induction has made steroid withdrawal or avoidance a realistic option in renal transplantation.

Cardiovascular Risk Estimates and Risk Factors in Renal Transplant Recipients

Cardiovascular morbidity, including coronary artery disease and left ventricular hypertrophy, and mortality are high in patients following renal transplantation. Cardiovascular disease is thought to be due to traditional (hypertension, hyperlipidemia, diabetes mellitus and smoking) as well as nontraditional cardiovascular risk factors (microinflammation). Furthermore, immunosuppressive drugs, namely, calcineurin inhibitors, sirolimus, and steroids, have been reported to adversely affect cardiovascular risk factors (e.g., hypertension, hyperlipidemia, hyperglycemia). Evidence from comparative trials and from conversion studies suggest that blood pressure, hyperlipidemia, and hyperglycemia after renal transplantation may be differentially affected by the calcineurin inhibitors cyclosporine and tacrolimus. In the European Tacrolimus versus Cyclosporin A Microemulsion Renal Transplantation Study, 557 patients were randomly allocated to therapy with tacrolimus (n = 286) versus cyclosporine (n = 271). In addition, to blood pressure, serum cholesterol, HDL cholesterol, triglycerides, and blood glucose, we estimated the 10-year risk of coronary heart disease (Framingham risk score). Tacrolimus resulted in a significantly lower time-weighted average of serum cholesterol (P < .001), and mean arterial blood pressure (P < .05), but a higher time-weighted average of blood glucose (P < .01) than cyclosporine. Mean 10-year coronary artery disease risk estimate was significantly lower in men treated with tacrolimus, (10.0% versus 13.2%; P < .01) but was unchanged in women (4.7% versus 7.0%). Tacrolimus and cyclosporine microemulsion have compound-specific effects on cardiovascular risk factors that differentially affect the predicted rate of coronary artery disease.

Renal effects of gadopentetate dimeglumine in patients with normal and impaired renal function

Gadolinium chelates are widely used in magnetic resonance imaging as contrast medium in patients with nephropathy. However, only few studies have investigated the effect of gadolinium on serum creatinine concentration and estimated GFR as surrogate markers of renal function. This study was performed to evaluate the effect of gadopentetate dimeglumine in a dose sufficient for diagnostic and interventional purposes on renal function in a large sample of patients. We analyzed serum creatinine and serum-urea levels before and after the administration of gadopentetate dimeglumine in patients with normal and patients with pre-existing impaired renal function. Age, height, body mass, sex, medication and preexisting illnesses such as diabetes, renal artery stenosis and heart disease were monitored. In 181 patients with normal renal function, there was no statistically significant change in serum creatinine concentration after the administration of gadopentetate dimeglumine (at baseline: 0.72 +/- 0.18 mg/dl, after gadolinium: 0.73 +/- 0.22 mg/dl). In contrary, serum creatinine levels decreased significantly after the administration of gadolinium in 198 patients with pre-existing renal impairment (1.82 +/- 1.03 mg/dl before and 1.72 +/- 1.03 mg/dl after gadolinium) (p < 0.01). According to this surrogate marker of renal function, the change of estimated GFR in patients with normal baseline renal function was not significant, while in patients with impaired renal function, GFR increased after the administration of gadolinium (p < 0.001). The high diagnostic value of gadolinium contrast media is associated with a very small risk of adverse reactions. Our findings show that the administration of gadolinium even is associated with a decrease of serum creatinine in patients with pre-existing renal impairment. In conclusion, the use of gadolinium-based contrast media may be considered as a safe alternative in patients with impaired renal function for whom use of iodine-based contrast agents is prone to a high rate of radiocontrast-induced nephropathy.

Effect of HMG-CoA-reductase inhibitors on survival in type 2 diabetes patients with end stage diabetic nephropathy

INTRODUCTION

We studied the effect of HMG-CoA-reductase inhibitor (= CSE-I) treatment on mortality in a population of hemodialysis patients with diabetic nephropathy due to type 2 diabetes. Since the efficacy of CSE-I in dialysis patients is discussed controversially, we tested the hypothesis that only patients with LDL-cholesterol > 100 mg/dl benefit from CSE-I.

METHODS

We enrolled all 445 prevalent chronic hemodialysis patients with end-stage diabetic nephropathy from 30 centres in Southern Germany from August 1999 to January 2000 for prospective study until December 2003. Fasting lipid profiles prior to dialysis session and a complete clinical phenotype were determined at inclusion. We formed 2 patient groups (serum LDL > vs. < or = 100 mg/dl). Only CSE-I were used as lipid lowering therapy in our cohort. 122 Patients were on CSE-I therapy during the study. All cause mortality (ACM) was the primary end point. Survival analysis was performed by Kaplan Meier and multivariate Cox regression analysis.

RESULTS

Multivariate regression analysis and Kaplan Meier survival analysis showed a decrease in risk for ACM for patients on CSE-I therapy, irrespective of lipid status (multivariate hazard ratio (= HR) 0.58; p = 0.049; ACM 72.1% (no CSE-I) vs. 59.7% (+ CSE-I); mean survival 2.37 +/- 0.08 years (no CSE-I) vs. 2.77 +/- 0.12 years (+ CSE-I), p = 0.003). In patients with LDL > 100 mg/dl, statin treatment was also associated with reduced ACM: 48.0% (+ CSE-I) vs. 70.1% (no CSE-I), (multivariate HR 0.28, CI 95% 0.11 - 0.75, p = 0.01), but not in patients with LDL < or = 100 mg/dl (HR 0.84, CI 95% 0.41 - 1.72 p = 0.63).

CONCLUSION

Our data indicates that hemodialysis patients with type 2 diabetic nephropathy may benefit from statin therapy irrespective of baseline LDL-cholesterol level. Patients with LDL > 100 mg/dl benefit most when treated with CSE-I.

Effect of genetic variation on therapy with angiotensin converting enzyme inhibitors or angiotensin receptor blockers in dialysis patients

INTRODUCTION

The role of interaction of polymorphisms in the Renin-Angiotensin-System (RAS) with angiotensin converting enzyme (ACE) or angiotensin receptor (AGTR1) inhibitors (RAS inhibitors) is unknown, as is the role of such therapy in end stage renal disease (ESRD) patients.

METHODS

We enrolled all 445 prevalent patients with diabetic nephropathy receiving maintenance hemodialysis in 30 centers in Southern Germany from August 1999 to January 2000 for prospective survival analysis until December 2003. Blood pressure and medication was recorded at inclusion. We determined survival specific for allelic variants of the ACE (insertion/deletion), Angiotensinogen (M235T) and AGTR1 (A1166C) genes. The effect of therapy with RAS inhibitors at study inclusion was determined for the allelic variants of each gene. The primary end point was all cause mortality (ACM).

RESULTS

For all polymorphisms, and for therapy with RAS inhibitors there was no significant effect on survival in the complete collective (n = 445), though there was an insignificant trend for improved survival in patients on AGTR1 antagonists. Increased ACM risk was associated with treatment with RAS inhibitors only in patients homozygous for the wild type AGTR1 1166A allele (HR 1.65, p = 0.01). For all other polymorphisms, therapy with RAS inhibitors had no significant effect on ACM, irrespective of genotype. Similar results were obtained in patients with systolic ventricular dysfunction.

CONCLUSION

Our data do not show a survival advantage for type 2 diabetes hemodialysis patients receiving RAS inhibiting therapy. In addition, our data indicate that allelic variation in RAS genes and pharmacogenetic interaction with RAS inhibition does not affect mortality risk in diabetic hemodialysis patients.