Endopeptidase Cleavage of Anti-Glomerular Basement Membrane Antibodies in vivo in Severe Kidney Disease: An Open-Label Phase 2a Study.

BACKGROUND: The prognosis for kidney survival is poor in patients presenting with circulating anti-glomerular basement membrane (GBM) antibodies and severe kidney injury. It is unknown if treatment with an endopeptidase that cleaves circulating and kidney bound IgG can alter the prognosis. METHODS: An investigator-driven phase 2a one-arm study (EudraCT 2016-004082-39) was performed in 17 hospitals in five European countries. A single dose of 0.25 mg/kg of imlifidase was given to 15 adults with circulating anti-GBM antibodies and an eGFR <15 ml/min per 1.73m2. All patients received standard treatment with cyclophosphamide and corticosteroids, but plasma exchange only if autoantibodies rebounded. The primary outcomes were safety and dialysis independency at 6 months. RESULTS: At inclusion, ten patients were dialysis dependent and the other five had eGFR levels between 7 and 14 ml/min per 1.73m2. The median age was 61 years (range 19-77), six were women, and six were also positive for anti-neutrophil cytoplasmic antibodies. Then 6 hours after imlifidase infusion, all patients had anti-GBM antibodies levels below the reference range of a prespecified assay. At 6 months 67% (ten out of 15) were dialysis independent. This is significantly higher compared with 18% (nine out of 50) in a historical control cohort (P<0.001, Fisher's exact test). Eight serious adverse events (including one death) were reported, none assessed as probably or possibly related to the study drug. CONCLUSIONS: In this pilot study, the use of imlifidase was associated with a better outcome compared with earlier publications, without major safety issues, but the findings need to be confirmed in a randomized controlled trial.Clinical Trial registration number: EUDRACT 2016-004082-39 https://www.clinicaltrialsregister.eu/ctr-search/trial/2007-001377-28/results.

Day-to-day variation of the kidney proximal tubular injury markers urinary cystatin C, KIM1, and NGAL in patients with chronic kidney disease.

Background: It is important to know the intraindividual variation of biomarkers to be able to distinguish a change of a biomarker due to the course of the disease from the normal biological variation of the marker. The purpose of this study was to investigate the day-to-day variability of urine markers in nephrology patients.Materials: 23 nephrology patients were included in the study. First morning urine samples were collected daily for ten consecutive days and analyzed for U-cystatin C, U-KIM1, U-NGAL and U-creatinine. The day-to-day variation was calculated as concentrations of the markers and as creatinine ratios. Values deviating more than the 90th percentile of the normal intraindividual variation was used to define a disease/treatment specific change.Results: The day-to-day coefficient of variation (CV) for individual patients varied between 9.6 and 100.3% for NGAL (mean 45.6%) and between 8.8 and 107.3% for the NGAL/creatinine ratio (mean 43.8%). The corresponding values for KIM1 were between 10.9 and 60.2% (mean 30.1%) and for the ratio between 8.7 and 59.8% (mean 23.4%) and for cystatin C 3.8-67.4% (mean 25.0%) and for the cystatin C/creatinine ratio 5.9-78.4% (mean 24.8%).Conclusions: The similar intraindividual CV values between the renal tubules damage markers and their corresponding creatinine ratios speaks against using creatinine ratio. Using the 90th percentiles of the CV values as a limit for clinical change means that NGAL has to change by 83.3%, KIM1 by 45.5% and Cystatin C by 46.3% before the change can be considered clinically significant in patients with chronic kidney disease.

The IgG-degrading enzyme of Streptococcus pyogenes causes rapid clearance of anti-glomerular basement membrane antibodies in patients with refractory anti-glomerular basement membrane disease.

In anti-glomerular basement membrane (anti-GBM) disease, IgG class autoantibodies induce rapidly progressive glomerulonephritis. Regrettably, many patients are diagnosed at a late stage when even intensive conventional treatment fails to restore renal function The endopeptidase IdeS (Immunoglobulin G degrading enzyme of Streptococcus pyogenes) (imliflidase) rapidly cleaves all human IgG subclasses into F(ab')2 and Fc fragments. We received permission to treat three patients with refractory anti-GBM nephritis without pulmonary involvement on a compassionate basis. All patients were dialysis-dependent for days or weeks when treated, and all had high levels of circulating anti-GBM despite plasma exchange. A single dose of IdeS led to complete clearance of circulating anti-GBM antibodies in all three patients. After about a week, all rebounded but the rebounds were easily managed by plasma exchange in two of three cases. Renal histology demonstrated severe crescentic glomerulonephritis with acute but mainly chronic changes. Staining for the Fc fragment was negative in all while Fab was positive in two patients. Unfortunately, none of the patients regained independent renal function. Thus, treatment with IdeS led to rapid clearance of circulating and kidney bound anti-GBM antibodies. The clinical utility, dosing and usage to preserve renal function remain to be determined.

Measuring GFR: a systematic review.

BACKGROUND: No comprehensive systematic review of the accuracy of glomerular filtration rate (GFR) measurement methods using renal inulin clearance as reference has been published. STUDY DESIGN: Systematic review with meta-analysis of cross-sectional diagnostic studies. SETTING & POPULATION: Published original studies and systematic reviews in any population. SELECTION CRITERIA FOR STUDIES: Index and reference measurements conducted within 48 hours; at least 15 participants studied; GFR markers measured in plasma or urine; plasma clearance calculation algorithm verified in another study; tubular secretion of creatinine had not been blocked by medicines. INDEX TESTS: Endogenous creatinine clearance; renal or plasma clearance of chromium 51-labeled ethylenediaminetetraacetic acid (51Cr-EDTA), diethylenetriaminepentaacetic acid (DTPA), iohexol, and iothalamate; and plasma clearance of inulin. REFERENCE TEST: Renal inulin clearance measured under continuous inulin infusion and urine collection. RESULTS: Mean bias <10%, median bias <5%, the proportion of errors in the index measurements that did not exceed 30% (P30) ≥80%, and P10 ≥50% were set as requirements for sufficient accuracy. Based on the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach, the quality of evidence across studies was rated for each index method. Renal clearance of iothalamate measured GFR with sufficient accuracy (strong evidence). Renal and plasma clearance of 51Cr-EDTA and plasma clearance of iohexol were sufficiently accurate to measure GFR (moderately strong evidence). Renal clearance of DTPA, renal clearance of iohexol, and plasma clearance of inulin had sufficient accuracy (limited evidence). Endogenous creatinine clearance was an inaccurate method (strong evidence), as was plasma clearance of DTPA (limited evidence). The evidence to determine the accuracy of plasma iothalamate clearance was insufficient. With the exception of plasma clearance of inulin, only renal clearance methods had P30 >90%. LIMITATIONS: The included studies were few and most were old and small, which may limit generalizability. Requirements for sufficient accuracy may depend on clinical setting. CONCLUSIONS: At least moderately strong evidence suggests that renal clearance of 51Cr-EDTA or iothalamate and plasma clearance of 51Cr-EDTA or iohexol are sufficiently accurate methods to measure GFR.

Uric acid and clinical correlates of endothelial function in kidney transplant recipients.

UNLABELLED: Uric acid is associated with increased mortality in kidney transplant recipients (KTRs), but it is uncertain if this involves endothelial dysfunction. We hypothesized, first, that there was an association between uric acid and endothelial function, and second, that there were associations between endothelial function and cardiac and mortality risk scores. METHODS: One hundred and fifty-two patients were examined 10 wk after kidney transplantation by two measures of endothelial function, the brachial artery flow-mediated dilatation (FMD) expressed as percent dilatation (FMD%), and fingertip peripheral arterial tone (PAT) expressed as log-reactive hyperemia index (LnRHI). Risk scores were calculated from a recently validated formula. Other clinical correlates of endothelial function were described in stepwise linear regression models. RESULTS: Uric acid was associated negatively with FMD% in an age- and gender-adjusted model, while not in the multivariable model. No association was shown between uric acid and LnRHI. FMD% was associated negatively with risk scores in both crude and age- and gender-adjusted models (p < 0.01). LnRHI was associated negatively with risk scores in the latter model only (p < 0.05). CONCLUSIONS: Uric acid was neither associated with FMD% nor LnRHI in KTRs. There were significant associations between endothelial function indices and cardiac and mortality risk scores.

Cardiovascular Risk Following Conversion to Belatacept From a Calcineurin Inhibitor in Kidney Transplant Recipients: A Randomized Clinical Trial.

Rationale & Objective: In kidney transplant recipients (KTRs), a belatacept-based immunosuppressive regimen is associated with beneficial effects on cardiovascular (CV) risk factors compared with calcineurin inhibitor (CNI)-based regimens. Our objective was to compare the calculated CV risk between belatacept and CNI (predominantly tacrolimus) treatments using a validated model developed for KTRs. Study Design: Prospective, randomized, open-label, parallel-group, investigator-initiated, international multicenter trial. Setting & Participants: KTRs aged 18-80 years with a stable graft function (estimated glomerular filtration rate > 20 mL/min/1.73 m2), 3-60 months after transplantation, treated with tacrolimus or cyclosporine A, were eligible for inclusion. Intervention: Continuation with a CNI-based regimen or switch to belatacept for 12 months. Outcomes: Comparison of the change in the estimated 7-year risk of major adverse CV events and all-cause mortality, changes in traditional markers of CV health, as well as measures of arterial stiffness. Results: Among the 105 KTRs randomized, we found no differences between the treatment groups in the predicted risk for major adverse CV events or mortality. Diastolic blood pressure, measured both centrally by using a SphygmoCor device and peripherally, was lower after the belatacept treatment than after the CNI treatment. The mean changes in traditional cardiovascular (CV) risk factors, including kidney transplant function, were otherwise similar in both the treatment groups. The belatacept group had 4 acute rejection episodes; 2 were severe rejections, of which 1 led to graft loss. Limitations: The heterogeneous baseline estimated glomerular filtration rate and time from transplantation to trial enrollment in the participants. A limited study duration of 1 year. Conclusions: We found no effects on the calculated CV risk by switching to the belatacept treatment. Participants in the belatacept group had not only lower central and peripheral diastolic blood pressure but also a higher rejection rate. Funding: The trial has received a financial grant from Bristol-Myers Squibb. Trial Registration: EudraCT no. 2013-001178-20.

Novel Biomarkers Detected by Proteomics Predict Death and Cardiovascular Events in Hemodialysis Patients.

End-stage kidney disease increases mortality and the risk of cardiovascular (CV) disease. It is crucial to explore novel biomarkers to predict CV disease in the complex setting of patients receiving hemodialysis (HD). This study investigated the association between 92 targeted proteins with all-cause death, CV death, and composite vascular events (CVEs) in HD patients. From December 2010 to March 2011, 331 HD patients were included and followed prospectively for 5 years. Serum was analyzed for 92 CV-related proteins using Proseek Multiplex Cardiovascular I panel, a high-sensitivity assay based on proximity extension assay (PEA) technology. The association between biomarkers and all-cause death, CV death, and CVEs was evaluated using Cox-regression analyses. Of the PEA-based proteins, we identified 20 proteins associated with risk of all-cause death, 7 proteins associated with risk of CV death, and 17 proteins associated with risk of CVEs, independent of established risk factors. Interleukin-8 (IL-8), T-cell immunoglobulin and mucin domain 1 (TIM-1), and C-C motif chemokine 20 (CCL20) were associated with increased risk of all-cause death, CV death, and CVE in multivariable-adjusted models. Stem cell factor (SCF) and Galanin peptides (GAL) were associated with both decreased risk of all-cause death and CV death. In conclusion, IL-8, TIM-1, and CCL20 predicted death and CV outcomes in HD patients. Novel findings were that SCF and GAL were associated with a lower risk of all-cause death and CV death. The SCF warrants further study with regard to its possible biological effect in HD patients.

Albumin Urinary Excretion Is Associated with Increased Levels of Urinary Chemokines, Cytokines, and Growth Factors Levels in Humans.

The aim of the present study was to study the associations between urine albumin excretion, and a large number of urinary chemokines, cytokines, and growth factors in a normal population. We selected 90 urine samples from individuals without CVD, diabetes, stroke or kidney disease belonging to the Prospective Investigation of the Vasculature in Uppsala Seniors Study (41 males and 49 females, all aged 75 years). Urinary cytokine levels were analyzed with two multiplex assays (proximity extension assays) and the cytokine levels were correlated with urine albumin. After adjustment for sex, body mass index (BMI), estimated glomerular filtration rate (eGFR), smoking and multiplicity testing, 11 biomarkers remained significantly associated with urine albumin: thrombospondin 2, interleukin 6, interleukin 8, hepatocyte growth factor, matrix metalloproteinase-12 (MMP-12), C-X-C motif chemokine 9, tumor necrosis factor receptor superfamily member 11B, osteoprotegerin, growth-regulated alpha protein, C-X-C motif chemokine 6, oncostatin-M (OSM) and fatty acid-binding protein, intestinal, despite large differences in molecular weights. In this study, we found associations between urinary albumin and both small and large urine proteins. Additional studies are warranted to identify cytokine patterns and potential progression markers in various renal diseases.

Strong Associations Between Early Tubular Damage and Urinary Cytokine, Chemokine, and Growth Factor Levels in Elderly Males and Females.

Acute tubular necrosis is associated with high mortality rates and it is important to develop new biomarkers for tubular damage. The aim of this study was to investigate the effect of early tubular damage on a large number of urinary cytokines, chemokines, and growth factors. We selected 90 urine samples from the Prospective Investigation of the Vasculature in Uppsala Seniors Study (41 males and 49 females). The tubular damage markers cystatin C, neutrophil gelatinase-associated lipocalin (NGAL), and kidney injury molecule-1 (KIM-1) were analyzed in the urine samples and urinary cytokine levels were analyzed with 2 multiplex assays (proximity extension assay). After adjustment for sex, body mass index, estimated glomerular filtration rate, smoking, and multiplicity testing using the false discovery rate approach, there remained 26 cytokines that correlated significantly with urine cystatin C, 27 cytokines that correlated with NGAL, and 66 cytokines that correlated with KIM-1. Tubular damage shows a strong association with urinary cytokines, chemokines, and growth factors. Our findings indicate that multiplex proteomics could be a promising new approach to explore the complex effects of tubular damage.

Associations Between Apolipoprotein A1, High-Density Lipoprotein Cholesterol, and Urinary Cytokine Levels in Elderly Males and Females.

There exists a close relationship between cardiovascular diseases and chronic kidney disease. Apolipoprotein A1 and high-density lipoprotein (HDL) cholesterol are widely used as cardiovascular risk markers but they also have anti-inflammatory properties. The aim of this study was to investigate any associations between HDL levels and cytokine levels in urine. We randomly selected 90 urine samples from the Prospective Investigation of the Vasculature in Uppsala Seniors Study (41 males and 49 females). The samples were analyzed with 2 multiplex assays, Multiplex Inflammation I and Cardiovascular II kits (Olink Bioscience, Uppsala, Sweden). We analyzed the correlations between 158 cytokines in urine with apolipoprotein A1, HDL cholesterol, apolipoprotein B, and low-density lipoprotein cholesterol. There were strong correlations for apolipoprotein A1 and HDL cholesterol with individual cytokines. After adjustment for multiplicity testing, there were 33 significant correlations between apolipoprotein A1 and cytokine levels and 14 of these were also significantly correlated with HDL cholesterol. The strongest associations were observed for IL-1α, SPON2, RAGE, PAR-1, TRAIL-R2, IL-4RA, TNFRSF11A, and SCF. A total of 28 out of 33 correlations were negative, indicating a negative relationship between apolipoprotein A1 and urinary cytokines. The study shows a negative correlation between apolipoprotein A1 and HDL cholesterol and urinary cytokine levels. The finding is in agreement with the anti-inflammatory properties of HDL.

Metabolic syndrome and cardiovascular risk in renal transplant recipients: effects of statin treatment.

BACKGROUND: Renal transplant recipients (RTR) have high risk for cardiovascular disease (CVD). They also have high prevalence of insulin resistance and metabolic syndrome (MS). Statin treatment reduces CVD risk in RTR. The aim was to study MS as CVD risk factor in RTR, and to investigate the effect of statin treatment in RTR with MS. METHODS: In total, 1706 non-diabetic RTR from the Assessment of Lescol in Renal Transplantation trial were followed for 7-8 yr. The captured endpoints included major adverse cardiac events [MACE, defined as cardiac death (CD), non-fatal myocardial infarction or coronary revascularization procedure], and CD. MS was defined at baseline according to Adult Treatment Panel III definition with waist girth replaced by body mass index > or =30 kg/m2. RESULTS: MS was diagnosed in 32% of the patients. During the follow-up, MACE incidence was 16% in those with MS and 11% in those without MS (p < 0.001). Statin treatment reduced MACE risk by 53% in the group with MS. CD risk was 74% higher in RTR with MS (p = 0.012), and statin treatment reduced CD risk in those with MS (p = 0.03). CONCLUSIONS: RTR with MS have increased risk for CVD. RTR with MS are an easily identifiable group of patients who benefit from statin treatment.

Acute effects of haemodialysis on circulating microparticles.

BACKGROUND: Microparticles (MPs) are small cell membrane-derived vesicles regarded as both biomarkers and mediators of biological effects. Elevated levels of MPs have previously been associated with endothelial dysfunction and predict cardiovascular death in patients with end-stage renal disease. The objective of this study was to measure change in MP concentrations in contemporary haemodialysis (HD). METHODS: Blood was sampled from 20 consecutive HD patients before and 1 h into the HD session. MPs were measured by flow cytometry and phenotyped based on surface markers. RESULTS: Concentrations of platelet (CD41+) (P = 0.039), endothelial (CD62E+) (P = 0.004) and monocyte-derived MPs (CD14+) (P < 0.001) significantly increased during HD. Similarly, endothelial- (P = 0.007) and monocyte-derived MPs (P = 0.001) expressing tissue factor (TF) significantly increased as well as MPs expressing Klotho (P = 0.003) and receptor for advanced glycation end products (RAGE) (P = 0.009). Furthermore, MPs expressing platelet activation markers P-selectin (P = 0.009) and CD40L (P = 0.045) also significantly increased. The increase of endothelial (P = 0.034), monocyte (P = 0.014) and RAGE+ MPs (P = 0.032) as well as TF+ platelet-derived MPs (P = 0.043) was significantly higher in patients treated with low-flux compared with high-flux dialysers. CONCLUSION: Dialysis triggers release of MPs of various origins with marked differences between high-flux and low-flux dialysers. The MPs carry surface molecules that could possibly influence coagulation, inflammation, oxidative stress and endothelial dysfunction. The clinical impact of these findings remains to be established in future studies.

Effects of sauna bath on heart failure: A systematic review and meta-analysis.

BACKGROUND: Sauna bath has potential as a lifestyle treatment modality for heart failure (HF). It is important to analyze the current evidence to help suggest paths of future study and potential for clinical application. HYPOTHESIS: Sauna bath has a positive effect on HF patients. METHODS: PubMed, Cochrane Library, and CINAHL databases were searched to identify randomized and nonrandomized controlled studies to compare effects of sauna bath with no sauna bath. Studies were searched for both infrared sauna bath and Finnish sauna bath. The strength of evidence was rated using a modified GRADE approach. Out of 1444 studies, nine met the inclusion criteria and were included in this review. Seven of these nine studies were included in the meta-analysis. Only studies with infrared sauna bath met the inclusion criteria. RESULTS: In the meta-analysis, exposure to an infrared sauna bath in 60°C for 15 minutes, followed by a 30-minute rest in warm environment, five times a week for 2 to 4 weeks, was associated with a significant reduction in B-type natriuretic peptide, cardiothoracic ratio, and an improvement in left-ventricular ejection fraction. There was no significant effect on left-ventricular end-diastolic diameter, left atrial diameter, systolic blood pressure, or diastolic blood pressure. The strength of evidence varied from moderate to insufficient. CONCLUSION: Infrared sauna bath was associated with short-term improvement in cardiac function. More evidence is needed about long-term effects of sauna bath and the effects of a Finnish sauna on cardiovascular health among patients with HF or other cardiovascular diseases.

Improvement in central arterial pressure waveform during hemodialysis is related to a reduction in asymmetric dimethylarginine (ADMA) levels.

BACKGROUND: Cardiovascular mortality is high in hemodialysis (HD) patients. Early arterial pressure wave reflections, reflecting arterial stiffness and the endogenous nitric oxide synthesis inhibitor asymmetric dimethylarginine (ADMA) levels predict mortality in HD patients. Therefore, we aimed to study changes in ADMA levels and central arterial pressure waveform during HD. METHODS: Thirty-two chronic HD patients were studied before and after a HD session. In a subset of 22 patients without arrhythmias, pulse wave analysis was performed on radial artery (SphygmoCor). Augmentation index (AIx), defined as difference between the second and first systolic peak divided by central pulse pressure, was used as a measure of arterial stiffness. ADMA was measured in plasma with the ELISA technique. Homocysteine was measured in plasma using the EIA technique. RESULTS: HD reduced both AIx (19%; p = 0.003) and ADMA levels (17%; p < 0.001). The magnitudes of changes in AIx and ADMA during HD were correlated (r = 0.44; p = 0.045). Mean arterial pressure change was not significant. HD reduced homocysteine levels, but homocysteine was not related to ADMA or AIx. CONCLUSION: The reduction in ADMA level seen after HD was associated with improvement in the central arterial pressure waveform, suggesting involvement of nitric oxide in the regulation of arterial stiffness in HD patients.

Cardiovascular disease in haemodialysis: role of the intravascular innate immune system.

Haemodialysis is a life-saving renal replacement modality for end-stage renal disease, but this therapy also represents a major challenge to the intravascular innate immune system, which is comprised of the complement, contact and coagulation systems. Chronic inflammation is strongly associated with cardiovascular disease (CVD) in patients on haemodialysis. Biomaterial-induced contact activation of proteins within the plasma cascade systems occurs during haemodialysis and initially leads to local generation of inflammatory mediators on the biomaterial surface. The inflammation is spread by soluble activation products and mediators that are generated during haemodialysis and transported in the extracorporeal circuit back into the patient together with activated leukocytes and platelets. The combined effect is activation of the endothelium of the cardiovascular system, which loses its anti-thrombotic and anti-inflammatory properties, leading to atherogenesis and arteriosclerosis. This concept suggests that maximum suppression of the intravascular innate immune system is needed to minimize the risk of CVD in patients on haemodialysis. A potential approach to achieve this goal is to treat patients with broad-specificity systemic drugs that target more than one of the intravascular cascade systems. Alternatively, 'stealth' biomaterials that cause minimal cascade system activation could be used in haemodialysis circuits.

Iohexol plasma clearance for measuring glomerular filtration rate in clinical practice and research: a review. Part 2: Why to measure glomerular filtration rate with iohexol?

A reliable assessment of glomerular filtration rate (GFR) is of paramount importance in clinical practice as well as epidemiological and clinical research settings. It is recommended by Kidney Disease: Improving Global Outcomes guidelines in specific populations (anorectic, cirrhotic, obese, renal and non-renal transplant patients) where estimation equations are unreliable. Measured GFR is the only valuable test to confirm or confute the status of chronic kidney disease (CKD), to evaluate the slope of renal function decay over time, to assess the suitability of living kidney donors and for dosing of potentially toxic medication with a narrow therapeutic index. Abnormally elevated GFR or hyperfiltration in patients with diabetes or obesity can be correctly diagnosed only by measuring GFR. GFR measurement contributes to assessing the true CKD prevalence rate, avoiding discrepancies due to GFR estimation with different equations. Using measured GFR, successfully accomplished in large epidemiological studies, is the only way to study the potential link between decreased renal function and cardiovascular or total mortality, being sure that this association is not due to confounders, i.e. non-GFR determinants of biomarkers. In clinical research, it has been shown that measured GFR (or measured GFR slope) as a secondary endpoint as compared with estimated GFR detected subtle treatment effects and obtained these results with a comparatively smaller sample size than trials choosing estimated GFR. Measuring GFR by iohexol has several advantages: simplicity, low cost, stability and low interlaboratory variation. Iohexol plasma clearance represents the best chance for implementing a standardized GFR measurement protocol applicable worldwide both in clinical practice and in research.

Iohexol plasma clearance for measuring glomerular filtration rate in clinical practice and research: a review. Part 1: How to measure glomerular filtration rate with iohexol?

While there is general agreement on the necessity to measure glomerular filtration rate (GFR) in many clinical situations, there is less agreement on the best method to achieve this purpose. As the gold standard method for GFR determination, urinary (or renal) clearance of inulin, fades into the background due to inconvenience and high cost, a diversity of filtration markers and protocols compete to replace it. In this review, we suggest that iohexol, a non-ionic contrast agent, is most suited to replace inulin as the marker of choice for GFR determination. Iohexol comes very close to fulfilling all requirements for an ideal GFR marker in terms of low extra-renal excretion, low protein binding and in being neither secreted nor reabsorbed by the kidney. In addition, iohexol is virtually non-toxic and carries a low cost. As iohexol is stable in plasma, administration and sample analysis can be separated in both space and time, allowing access to GFR determination across different settings. An external proficiency programme operated by Equalis AB, Sweden, exists for iohexol, facilitating interlaboratory comparison of results. Plasma clearance measurement is the protocol of choice as it combines a reliable GFR determination with convenience for the patient. Single-sample protocols dominate, but multiple-sample protocols may be more accurate in specific situations. In low GFRs one or more late samples should be included to improve accuracy. In patients with large oedema or ascites, urinary clearance protocols should be employed. In conclusion, plasma clearance of iohexol may well be the best candidate for a common GFR determination method.

Renal dysfunction as a risk factor for mortality and cardiovascular disease in renal transplantation: experience from the Assessment of Lescol in Renal Transplantation trial.

BACKGROUND: Renal-transplant recipients have shortened life expectancy primarily because of premature cardiovascular disease. Traditional and nontraditional risk factors for cardiovascular disease are prevalent in renal patients. In renal-transplant recipients, immunosuppressive therapy can be nephrotoxic and aggravate cardiovascular disease risk factors. Renal dysfunction has been established as a risk factor for cardiovascular disease and mortality in different populations. We evaluated the effects of baseline renal-transplant function on mortality and cardiovascular and renal endpoints in 1,052 placebo-treated patients of the Assessment of Lescol in Renal Transplantation trial. METHODS: All renal-transplant recipients were on cyclosporine-based immunosuppressive therapy. Follow-up was 5 to 6 years, and endpoints included cardiac death, noncardiovascular death, all-cause mortality, major adverse cardiac event (MACE), stroke, nonfatal myocardial infarction, and graft loss. RESULTS: Baseline serum creatinine was strongly and independently associated with increased cardiac, noncardiovascular, and all-cause mortality, as well as MACE and graft loss. Serum creatinine was not a risk factor for stroke or nonfatal myocardial infarction. CONCLUSIONS: Elevated baseline serum creatinine in renal-transplant recipients is a strong and independent risk factor for all-cause, noncardiovascular and cardiac mortality, MACE, and graft loss.

Endothelial function, CRP and oxidative stress in chronic kidney disease.

BACKGROUND: Chronic kidney disease (CKD) is associated with increased morbidity and mortality in cardiovascular disease (CVD). Apart from traditional risk factors, chronic inflammation, oxidative stress, malnutrition and endothelial dysfunction are important in CVD development in renal patients. Our aim was to investigate the relationship between high sensitivity C-reactive protein (CRP), endothelium dependent vasodilation (EDV) and oxidative stress markers in patients with CKD K/DOQI stage 3-5. METHODS: Measurements of CRP, conjugated dienes (CD), lipid hydroperoxide (LOOH), oxidized low density lipoprotein,glutathione and albumin were performed in 44 consecutive patients with CKD stage 3-5. EDV was measured by methacholine infusion in the brachial artery and venous occlusion plethysmography. RESULTS: Patients with high CRP had significantly lower glomerular filtration rates and albumin, but increased LOOH and CD. In multiple regression analysis, only LOOH and CD remained significant. Patients with poor EDV had increased urea and lower glutathione (GSH). In multiple regression analysis, GSH and urea were independently related to EDV. No correlation was found between CRP and endothelial function. CONCLUSION: CRP was related to lipid peroxidation, while endothelial function was related to intracellular oxidative stress in patients with CKD. CRP and EDV were unrelated to each other. Therefore, CRP and endothelial function could provide complementary prognostic information regarding future cardiovascular disorders in renal patients.