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We have presented a case of an angiogenic renal tumor in a patient from a family with von Hippel Lindau' syndrome (VHL). The patient has bilateral clear cell carcinoma (CCC) .Molecular mechanisms recently discovered are described in order to require a better understanding of the development of this disease. The knowledge of these mechanisms, may allow to achieve better therapeutic approaches to neutralize the tumors of VHL disease. In this patient, an antiproliferative, antiangiogenic therapy was preferred. Rapamycin was chosen due to the lack of information regarding the use of antitumoral monoclonal antibodies in dialysis patients. VHL disease needs to be early detected, because many of its effects can be readily treated assuring a better survival for these patients. Antiangiogenic therapy can be used for CCC in this disease with promising results. [ABSTRACT FROM AUTHOR]

Urinary excretion of aluminium after a successful transplant can reverse pre-transplant aluminium intoxication. We have evaluated the time course of urinary aluminium excretion and its correlation with several parameters of renal function and mineral metabolism in 49 patients (33 men and 16 women) with a wide range of pre-transplant serum aluminium concentrations, performing sequential determinations at pre-transplant time and at 7, 30, 60, and 90 post-transplant days. [ABSTRACT FROM PUBLISHER]

We present a patient with a rare systemic autoinflammatory disease (mevalonate kinase deficiency -MKD-) with the identification of two heterozygous variants (c.1129G>A and c.32C>T) in the Mevalonate Kinase gene, detected by next generation sequencing and a highly prevalent glomerulonephritis (IgA nephropathy). The patient presents clinically with a monthly recurrent periodic fever from 12 days of age, accompanied by mucocutaneous lesions (maculopapular rash in extremities, aphthous stomatitis), joint (arthralgias in ankles, wrists and knees), lymphoid (cervical lymphadenopathy, splenomegaly), gastrointestinal (diarrhea, abdominal pain) and kidney (hematuria and proteinuria) with repeated biopsies showing IgA nephropathy alternating activity with chronicity. During follow-up. The patients presented a poor therapeutic response to multiple immunosuppressive regimens used for 7 years (corticosteroids, azathioprine, mycophenolate, cyclophosphamide, rituximab and tocilizumab), and finally a good response to canakinumab. Four years after starting canakinumab, during the course of an infection due to a muscle abscess, the clinical presentation is complicated by a severe renal microvascular event (renal cortical necrosis -RCN-) with acute kidney injury and dialysis requirement. Therecurrent episodes of inflammation due to MKD could act as triggers for the reactivation of glomerulonephritis (which would explain the poor response to immunosuppressants and the rapid progression to histological chronicity) and to generate a microenvironment that predisposes the development of RCN in the face of a non-serious infection. A defect in IgA molecules has been described in MKD, a phenomenon also observed in IgA nephropathy. This raises the challenging hypothesis of a common pathogenetic link between all the patient's clinical manifestations.

There is no consensus on the best equation to estimate glomerular filtration rate (eGFR) in obese patients (OP). Objective: to evaluate the performance of the current equations and the new Argentinian Equation ("AE") to estimate GFR in OP. Two validation samples were used: internal (IVS, using 10-fold cross-validation) and temporary (TVS). OP whose GFR was measured (mGFR) with clearance of iothalamate between 2007/2017 (IVS, n = 189) and 2018/2019 (TVS, n = 26) were included. To evaluate the performance of the equations we used: bias (difference between eGFR and mGFR), P30 (percentage of estimates within ±30% of mGFR), Pearson's correlation (r) and percentage of correct classification (%CC) according to the stages of CKD. The median age was 50 years. Sixty percent had grade I obesity (G1-Ob), 25.1% G2-Ob and 14.9% G3-Ob, with a wide range in mGFR (5.6-173.1 mL/min/1.73 m 2 ). In the IVS, AE obtained a higher P30 (85.2%), r (0.86) and %CC (74.4%), with lower bias (-0.4 mL/min/1.73 m 2 ). In the TVS, AE obtained a higher P30 (88.5%), r (0.89) and %CC (84.6%). The performance of all equations was reduced in G3-Ob, but AE was the only one that obtained a P30 > 80% in all degrees. AE obtained better overall performance to estimate GFR in OP and could be useful in this population. Conclusions from this study may not be generalizable to all populations of obese patients since they were derived from a study in a single center with a very specific ethnic mixed population.

Background: The continuous global rise of end-stage kidney disease creates a growing demand of economically beneficial home-based kidney replacement therapies such as peritoneal dialysis (PD). However, undesirable absorption and exposure of peritoneal tissues to glucose remain major limitations of PD., Methods: We compared a reference (standard) automated PD regimen 6 × 2 L 1.36% glucose (76 mmol/L) over 9 h with a novel, theoretically glucose sparing (optimised) prescription consisting of 'ultrafiltration cycles' with high glucose strength (126 mmol/L) and 'clearance cycles' with ultra-low, physiological glucose (5 mmol/L) for approximately 40% of the treatment time. Twenty-one prevalent PD patients underwent the optimised regimen (7 × 2 L 2.27% glucose + 5 × 2 L 0.1% glucose over 8 h) and the standard regimen in a crossover fashion. Six patients were excluded from data analysis., Results: Median glucose absorption was 43 g (IQR 41-54) and 44 g (40-55) for the standard and optimised intervention, respectively ( p = 1). Ultrafiltration volume, weekly Kt/V creatinine and urea were significantly improved during optimised interventions, while no difference in sodium removal was detected. Post hoc analysis showed significantly improved ultrafiltration efficiency (ml ultrafiltration per gram absorbed glucose) during optimised regimens. No adverse events were observed except one incidence of drain pain., Conclusion: Optimised treatments were feasible and well tolerated in this small pilot study. Despite no difference in absorbed glucose, results indicate possible improvements of ultrafiltration efficiency and small solute clearances by optimised regimens. Use of optimised prescriptions as glucose sparing strategy should be evaluated in larger study populations.

Guideline 1: A pathophysiological taxonomy: A pathophysiological classification of membrane dysfunction, which provides mechanistic links to functional characteristics, should be used when prescribing individualized dialysis or when planning modality transfer (e.g. to automated peritoneal dialysis (PD) or haemodialysis) in the context of shared and informed decision-making with the person on PD, taking individual circumstances and treatment goals into account. ( practice point )., Guideline 2a: Identification of fast peritoneal solute transfer rate (PSTR): It is recommended that the PSTR is determined from a 4-h peritoneal equilibration test (PET), using either 2.5%/2.27% or 4.25%/3.86% dextrose/glucose concentration and creatinine as the index solute. ( practice point ) This should be done early in the course dialysis treatment (between 6 weeks and 12 weeks) ( GRADE 1A ) and subsequently when clinically indicated. ( practice point )., Guideline 2b: Clinical implications and mitigation of fast solute transfer: A faster PSTR is associated with lower survival on PD. ( GRADE 1A ) This risk is in part due to the lower ultrafiltration (UF) and increased net fluid reabsorption that occurs when the PSTR is above the average value. The resulting lower net UF can be avoided by shortening glucose-based exchanges, using a polyglucose solution (icodextrin), and/or prescribing higher glucose concentrations. ( GRADE 1A ) Compared to glucose, use of icodextrin can translate into improved fluid status and fewer episodes of fluid overload. ( GRADE 1A ) Use of automated PD and icodextrin may mitigate the mortality risk associated with fast PSTR. ( practice point )., Guideline 3: Recognizing low UF capacity: This is easy to measure and a valuable screening test. Insufficient UF should be suspected when either (a) the net UF from a 4-h PET is <400 ml (3.86% glucose/4.25% dextrose) or <100 ml (2.27% glucose /2.5% dextrose), ( GRADE 1B ) and/or (b) the daily UF is insufficient to maintain adequate fluid status. ( practice point ) Besides membrane dysfunction, low UF capacity can also result from mechanical problems, leaks or increased fluid absorption across the peritoneal membrane not explained by fast PSTR., Guideline 4a: Diagnosing intrinsic membrane dysfunction (manifesting as low osmotic conductance to glucose) as a cause of UF insufficiency: When insufficient UF is suspected, the 4-h PET should be supplemented by measurement of the sodium dip at 1 h using a 3.86% glucose/4.25% dextrose exchange for diagnostic purposes. A sodium dip ≤5 mmol/L and/or a sodium sieving ratio ≤0.03 at 1 h indicates UF insufficiency. ( GRADE 2B )., Guideline 4b: Clinical implications of intrinsic membrane dysfunction (de novo or acquired): in the absence of residual kidney function, this is likely to necessitate the use of hypertonic glucose exchanges and possible transfer to haemodialysis. Acquired membrane injury, especially in the context of prolonged time on treatment, should prompt discussions about the risk of encapsulating peritoneal sclerosis. ( practice point )., Guideline 5: Additional membrane function tests: measures of peritoneal protein loss, intraperitoneal pressure and more complex tests that estimate osmotic conductance and 'lymphatic' reabsorption are not recommended for routine clinical practice but remain valuable research methods. ( practice point )., Guideline 6: Socioeconomic considerations: When resource constraints prevent the use of routine tests, consideration of membrane function should still be part of the clinical management and may be inferred from the daily UF in response to the prescription. ( practice point ).

Introduction: Unwanted glucose absorption during peritoneal dialysis (PD) remains a clinical challenge, especially in diabetic patients. Recent experimental data indicated that inhibitors of the sodium and glucose co-transporter (SGLT)-2 could act to reduce glucose uptake during PD, which raises the question of whether glucose absorption may also occur via intracellular or trans-cellular pathways., Methods: We performed PD in anesthetized Sprague-Dawley rats using a fill volume of 20 mL with either 1.5% glucose fluid or 4.25% glucose fluid for 120 min dwell time to evaluate the effects of SGLT2 inhibition by empagliflozin on peritoneal water and solute transport. To assess the diffusion capacity of glucose, we developed a modified equation to measure small solute diffusion capacity, taking convective- and free water transport into account., Results: SGLT2 inhibition markedly increased the urinary excretion of glucose and lowered plasma glucose after PD compared to sham groups. Glucose absorption for 1.5% glucose was 165 mg 95% CI (145-178) in sham animals and 157 mg 95% CI (137-172) for empagliflozin-treated animals. For 4.25% glucose, absorption of glucose was 474 mg 95% CI (425-494) and 472 mg 95% CI (420-506) for sham and empagliflozin groups, respectively. No significant changes in the transport of sodium or water across the peritoneal barrier could be detected., Conclusion: We could not confirm recent findings that SGLT2 inhibition reduced glucose absorption and increased osmotic water transport during experimental PD.

Background: Long-term consequences associated with kidney donation are controversial. Pre- and post-donation glomerular filtration rates (GFRs) are determinants of renal and cardiovascular risk weighting. In Latin America, there is limited experience in evaluating kidney function using GFR measurement techniques in kidney donors. The MDRD 4-variable and CKD-EPI equations are considered reasonable options. The objective of this study was to evaluate the performance of the MDRD and CKD-EPI equations in post-nephrectomy GFR dynamics in kidney donors., Materials and Methods: A prospective cohort study with GFR measurement and estimation in 189 kidney donors who underwent nephrectomy between 2007 and 2016 at the Hospital Privado Universitario de Córdoba [Private University Hospital of Córdoba] in Córdoba, Argentina. GFRs were evaluated before and after nephrectomy by iothalamate clearance determined by HPLC and by the MDRD and CKD-EPI equations for estimating GFR. Two groups were formed for this study: Group 1 (n=107), with an evaluation time subsequent to GFR stabilization (3 months) of up to 5 years, and Group 2 (n=82), with an evaluation time of 5-10 years following donation. Measured GFR (mGFR) was assessed by iothalamate clearance determined by HPLC., Results: Renal compensation values were 61.9% (52.0%-71.1%) and 75.6% (64.9%-84.4%) for Group 1 (n=107) and Group 2 (n=82), respectively. MDRD underestimated the GFR in 3.2% (90ml/min/1.73m 2 ) and 38.6% (60ml/min/1.73m 2 ) compared to the mGFR, and CKD-EPI underestimated the GFR in 2.6% (90ml/min/1.73 m 2 ) and 13.8% (60ml/min/1.73 m 2 ). Diagnostic performance was evaluated with a ROC curve (mGFR<60ml/min/1.73 m 2 ) for MDRD (ABC=0.66; CI: 0.59-0.73; sensitivity: 98.7%; specificity: 63.3%) and for CKD-EPI (ABC=0.79 CI: 0.73-0.85; sensitivity: 96.9%; specificity: 76.4%. Estimated GFR (eGFR) showed poor performance for estimating the glomerular filtration rate in the post-nephrectomy follow-up of donors over 50 years of age., Conclusions: Equations for estimating GFRs showed poor performance for long-term follow-up of post-nephrectomy GFRs. Measuring GFRs to determine kidney function is recommended in the screening and follow-up of some donors under the current selection criteria., (Copyright © 2020 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.)

The ABO incompatible (ABOi) living donor (LD) kidney transplant allows increasing the number of donors and reducing the time on the waiting list. The objectives of this study were to compare graft survival, patient survival, rejection risk factors and complications during the first year p ost-transplantation in patients who received an ABOi LD kidney transplant between 2014 and 2019 in our institution, matched according to sex, age and immunological risk with a control group of ABO compatible (ABOc) LD kidney transplants in the same period. Thirteen patients were included in each group. No significant differences were found between ABOi and ABOc in the incidence of delayed graft function (n = 0 vs. 1), bleeding (0 vs. 0), infections (13 vs. 13), cellular rejection (1 vs. 3) and humoral rejection (4 vs. 3) in the first year after transplantation. The rejection rate in ABOi do not seem to be related to blood incompatibility. No risk factors associated with rejection were found. Overall survival of patients was 100% in both groups, and graft survival was 92.3% in ABOi and 100% in ABOc (p = 1). ABOi kidney transplantation is an adequate feasible option in our environment for those who do not have compatible donors.

Cardiovascular disorders represent the leading cause of death in dialysis patients. Alterations of bone and mineral metabolism (BMM) and vascular calcifications play a fundamental role in it. The objective of this study was to evaluate the predictive role on cardiovascular mortality of the measurement of biomarkers of BMM and vascular calcifications. A prospective cohort study was performed. All prevalent patients on chronic dialysis in September 2009 at our institution, who completed the total of the complementary studies, were studied. BMM biomarkers were measured (FGF 23, fetuin A, PTH, calcium and phosphorus) and the vascular calcifications were evaluated using the Kauppila and Adragao scores. Follow-up was carried out until 1/1/2019, death or transplant. Of the 30 patients included, 7 (23.3%) died due to cardiovascular causes. The follow-up time was 44.1 ± 30.4 (range = 1.4-112) months. The Adragao score was the only predictive variable of long-term cardiovascular mortality (area under the curve = 0.82; 95% CI 0.64-0.94; p < 0.001). The best cut-off point was 5 (sensitivity = 85.7%; specificity = 78.3%). It was also an independent risk factor for cardiovascular mortality adjusted for age, diabetes mellitus, coronary heart disease, aortic calcifications, time spent on dialysis and follow-up time (adjusted OR = 1.77; 95% CI = 1.06-2.96; p = 0.028). The vascular calcifications quantified from the Adragao score were the only independent predictor of long-term cardiovascular mortality. This score represents a simple, useful and superior tool to the biomarkers of BMM.

Background: It has been estimated that automated peritoneal dialysis (APD) is currently the fastest growing renal replacement therapy in the world. However, in light of the growing number of diabetic patients on peritoneal dialysis (PD), the unwanted glucose absorption during APD remains problematic. Recent results, using an extended 3-pore model of APD, indicated that large reductions in glucose absorption are possible by using optimized bi-modal treatment regimens, having "UF cycles" using a higher glucose concentration, and "Clearance cycles" using a low concentration or, preferentially, no glucose. The present study is designed to test the theoretical prediction of a lower glucose absorption using these novel regimes., Methods: This study is a randomized single-center, open-label, prospective study. Prevalent PD patients between 18 and 75 years old without known catheter problems or recent peritonitis are eligible for inclusion. Patients are allocated to a first treatment session of either standard APD (6 × 2 L 1.36% over 9 h) or optimized APD (7 × 2 L 2.27% + 5 × 2 L 0.1% over 8 h). A second treatment session using the other treatment will be performed in a crossover fashion. Samples of the dialysis fluid will be taken before and after the treatment, and the volume of the dialysate before and after the treatment will be carefully assessed. The primary endpoint is difference in glucose absorption between the optimized and standard treatment. Secondary endpoints are ultrafiltration, sodium removal, Kt/V urea, and Kt/V Creatinine. The study will be closed when a total of 20 patients have successfully completed the interventions or terminated according to interim analysis. A Monte Carlo power analysis shows that the study has 80% power to detect a difference of 10 g (in line with that of theoretical results) in glucose absorption between the two treatments in 10 patients., Discussion: The present study is the first clinical investigation of optimized bi-modal treatments proposed by recent theoretical studies., Trial Registration: ClinicalTrials.gov identifier: NCT04017572. Registration date: July 12, 2019, retrospectively registered., Competing Interests: Competing interestsCMÖ has worked as a consultant and received speakers’ honoraria from the Baxter Healthcare Corporation. KB is currently pursuing a master thesis project in collaboration with Gambro Lundia AB (part of Baxter Healthcare Corporation)., (© The Author(s) 2020.)

Atypical hemolytic uremic syndrome (aHUS) is a rare entity. It is characterized by a thrombotic microangiopathy (nonimmune hemolytic anemia, thrombocytopenia, and acute renal failure), with a typical histopathology of thickening of capillary and arteriolar walls and an obstructive thrombosis of the vascular lumen. The syndrome is produced by a genetic or acquired deregulation of the alternative pathway of the complement system, with high rates of end stage renal disease, post-transplant recurrence, and high mortality. Mutations associated with factor H, factor B and complement C3 show the worst prognosis. Even though plasma therapy is occasionally useful, eculizumab is effective both for treatment and prevention of post-transplant recurrence. We describe here an adult case of congenital aHUS (C3 mutation) under preventive treatment with eculizumab after renal transplantation, with neither disease recurrence nor drug-related adverse events after a 36-months follow-up.

Patients receiving sub-optimal dose of hemodialysis have increased morbidity and mortality. The objectives of this study were to identify predisposing factors and causes of inadequate dialysis, and to design a practical algorithm for the management of these patients. A cross-sectional study was conducted. Ninety patients in chronic hemodialysis at Hospital Privado Universitario de Córdoba were included, during September 2015. Twenty two received sub-optimal dose of hemodialysis. Those with urea distribution volume (V) greater than 40 l (72 kg body weight approximately) are 11 times more likely (OR = 11.6; CI 95% = 3.2 to 51.7, p < 0.0001) to receive an inadequate dose of hemodialysis, than those with a smaller V. This situation is more frequent in men (OR = 3.5; 95% CI 1.01-15.8; p = 0.0292). V greater than 40 l was the only independent predictor of sub-dialysis in the multivariate analysis (OR = 10.3; 95% CI 2.8-37; p < 0.0004). The main cause of suboptimal dialysis was receiving a lower blood flow (Qb) than the prescribed (336.4 ± 45.8 ml/min vs. 402.3 ± 28.8 ml/min respectively, p < 0.0001) (n = 18). Other causes were identified: shorter duration of the session (n = 2), vascular access recirculation (n = 1), and error in the samples (n = 1). In conclusion, the only independent predisposing factor found in this study for sub-optimal dialysis is V greater than 40 l. The main cause was receiving a slower Qb than prescribed. From these findings, an algorithm for the management of these patients was developed.

For patients with chronic renal failure (CRF), kidney transplant (KT) is a better alternative to dialysis in terms of survival, life quality and costs. We studied the general characteristics, causes and survival rate of the dialysis population in 2010. We evaluated broader criteria for acceptance of transplants has affected the results of the procedure in that period. A total of 118 dialysis patients were included; mean age 56.9 ± 18.4 years, dialysis duration 45.5 ± 59.6 months, main cause of CRF was diabetes in 35 (30%), and 58 (49%) were included in waiting list for KT. Of the 34 patients who finished dialysis in 2010, 18 (53%) were KT, while 12 (35%) died (cardiovascular 50%, infectious 17%). Survival at 12 months was 85% for the total group, 98% on waiting list and 72% those who were not enrolled. During 2010 there were 88 KT, 62 with cadaveric donors (CD), 18 with living donors and 8 with double pancreas-kidney transplants. Recipients of CD were 50.7 years old, with 67 months on dialysis, 8 (13%) diabetics, and 12 (20%) with previous KT. Donors had a mean age of 45 years, 28 (45%) expanded criteria, and 27.7 hours of cold ischemia time. During an approximate follow-up of 11.4 months, 13 (21%) suffered acute graft rejection, survival was 88% for graft and 93% for patients. We emphasize KT as the main cause of success as regards dialysis. No differences in risk factors were found to significantly affect graft or patient survival.

A considerable percentage of patients exhibit anemia post kidney transplant. Its origin is multifactorial and the main causes involved depend on the post transplant period considered. We studied in a group of 134 consecutive patients the associated factors and the clinical implications of "late anemia" (6 months post transplant). Multiple regression analysis showed that post transplant oliguria and acute rejection episodes were significantly associated with anemia. Graft survival at 36 months was significantly reduced in the anemic group (83 % versus 96%, p < 0.01). No differences in patients survival or rate of cardiovascular events were observed. We concluded that anemia at 6 months post transplant is independently and significantly associated with events that reduced functioning renal mass and kidney survival.

Background: There are few data in Argentina on the prevalence and management of bone and mineral metabolism (BMM) in patients with chronic kidney disease (CKD)., Objectives and Methods: A survey was carried out in dialysis units in 2010 to measure the prevalence of and types of treatments for BMM disorders in Argentina. The data obtained was then compared to the published results from other large population studies. We recorded characteristics of dialysis centres and participating patients, the frequency of measurements and individual results for BMM biochemical markers, as well as the type of management used to control hyperphosphataemia and secondary hyperparathyroidism., Results: 1210 patients from 25 dialysis centres in Argentina participated in the study (representing 4.7% of the country’s prevalent dialysis population in 2010). The mean patient age was 55.3±17.6 years, 60.8% were male, 3.3% were on peritoneal dialysis and 29.1% suffered diabetes. In all centres, phosphataemia and calcaemia were measured on a monthly basis, 60% of centres measured intact parathyroid hormone (iPTH) every 6 months, 36% every 3 to 4 months, and 4% annually. As recommended by K/DOQI, 51.6% of patients had adequate levels of calcium (8.4-9.5 mg/dl), 51.6% had adequate phosphorus (3.5-5.5 mg/dl) and 21.1% displayed acceptable iPTH levels (150-300 pg/ml). 24% had iPTH <150 pg/ml and 54.5% >300 pg/ml. iPTH ≥600 pg/ml was present in 28.3%, and 13.3% had values ≥1000 pg/ml. These figures differed from those published by the DOPPS II study, in which 51.1% of patients had iPTH <150 pg/ml, and only 26.7% had iPTH ≥300 pg/ml. Calcium-based phosphate binders were used in 83.6% of the patients, 5.6% used sevelamer and 4.0% used aluminium-containing compounds. To achieve control of hyperparathyroidism, oral or intravenous calcitriol was predominantly used (50.5%) with a small percentage of patients receiving paricalcitol or doxercalciferol., Conclusions: The present study shows a high prevalence of secondary hyperparathyroidism, which differs from that published by other large population studies. There was a high proportion of patients with BMM markers outside the ranges suggested by K/DOQI. Mainly phosphate binders based on calcium and calcitriol continue to be used for the management of hyperphosphatemia and hyperparathyroidism respectively.

Background: The determination of the glomerular filtration rate (GFR) is critical for the selection of a potential kidney donor. The complex and impractical techniques for the measurement of GFR have led to the development of equations to estimate GFR. Modification of diet in renal disease (MDRD) formula is the most widely used but its performance is poor because it systematically underestimates GFR above 60 mL/min. A new formula called the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) seems to overcome this limitation but needs to be tested in healthy potential kidney donors., Methods: From 2007 to 2011, a cross-sectional study was performed on 85 adults who were candidates for living-related kidney donation. GFR was measured by nonradiolabeled iothalamate clearance determined by high-performance liquid chromatography, and renal function was estimated by using CKD-EPI and MDRD equations. The overall performance of the equations was analyzed, and the estimation for GFR above 90 mL/min was studied by means of receiver operating characteristic curves., Results: The mean (SD) (range) of the measured GFR was 116 (24) (64-160) mL/min per 1.73 m(2), estimated GFR with CKD-EPI was 108 (22) (64-153) mL/min per 1.73 m(2), and MDRD was 99 (28) (46-157) mL/min per 1.73 m(2). CKD-EPI presented lower bias (3.3 vs. 10.2 mL/min/1.73 m(2)), higher precision [interquartile range (minimum value-maximum value), 25 (53-140) vs. 32 (43-161) ml/min] and higher accuracy (100% vs. 89%) compared with MDRD., Conclusion: The CKD-EPI equation showed a higher performance than the MDRD equation in the GFR estimation of healthy population. CKD-EPI is applicable instead of MDRD, to subjects or candidates for kidney donation to avoid wrong GFR underestimates, which may lead to an inappropriate exclusion of candidates.

Sirolimus (rapamycin), an inhibitor of the mechanistic target of rapamycin (MTOR), was originally proposed as an immunosuppressant to prevent rejection of solid organ transplants. There were expectations that MTOR inhibitors would replace nephrotoxic calcineurin inhibitors (CNIs). Despite its potential advantages, evidence that sirolimus causes de novo or worsening proteinuria is unequivocal. Given the well-recognized proteinuric effect of MTOR inhibitors, we were interested in understanding its role in maintaining the glomerular filtration barrier. To investigate this in vivo, we developed a mouse model with a podocyte selective deletion of the Mtor gene (Mtor pod-KO).

Inhibitors of the mammalian target of rapamycin (MTOR) belong to a family of drugs with potent immunosuppressive, antiangiogenic, and antiproliferative properties. De novo or worsening proteinuria can occur during treatment with these agents, but the mechanism by which this occurs is unknown. We generated and characterized mice carrying a podocyte-selective knockout of the Mtor gene. Although Mtor was dispensable in developing podocytes, these mice developed proteinuria at 3 weeks and end stage renal failure by 5 weeks after birth. Podocytes from these mice exhibited an accumulation of the autophagosome marker LC3 (rat microtubule-associated protein 1 light chain 3), autophagosomes, autophagolysosomal vesicles, and damaged mitochondria. Similarly, human podocytes treated with the MTOR inhibitor rapamycin accumulated autophagosomes and autophagolysosomes. Taken together, these results suggest that disruption of the autophagic pathway may play a role in the pathogenesis of proteinuria in patients treated with MTOR inhibitors.

Current transplant success allows recipients with previous contraindications to transplant to have access to this procedure with more frequency and safety. The concept of high-risk patient has changed since the first stages of transplantation. In the first studies, the high-risk concept was based on probability of early graft failure or on a patient's clinical condition to cope with high perioperatory morbimortality. Later on, this concept implied immunological factors that were crucial to ensure transplant success because hypersensitized or polytransfused patients experienced a higher risk of acute rejection and subsequent graft loss. Afterward, the presence of various comorbidities would redefine the high-risk concept for renal transplant mainly considering recipient's clinical aspects. Currently, the change in epidemiological characteristics of patients starting dialysis causes that we now deal with a greater increase of elderly patients, diabetic patients, and patients with history of cardiovascular disease. Today, high-risk patients are those with clinical features that predict an increase in the risk of perioperative morbimortality or death with functioning graft. In this review, we will attempted to analyze currents results of renal transplant outcomes in terms of patients and graft survival in elderly patients, diabetic patients, and patients with previous cardiovascular disease from the most recent experiences in the literature and from experiences in our center. In any of the groups previously analyzed, survival offered by renal transplant is significantly higher compared to dialysis. Besides, these patients are the recipient group that benefit the most with the transplant because their mortality while remaining on dialysis is extremely high. Hence, renal transplantation should be offered more frequently to older patients, diabetic patients, and patients with pretransplant cardiac and peripheral vascular disease. A positive attitude toward renal transplantation is needed by physicians taking care of these patients from predialysis stages of chronic renal failure.

During the 2008 Congress of the International Society for Peritoneal Dialysis, academic nephrologists, nephrology societies, and government officials from Colombia, Brazil, Argentina, Chile, Central America, Ecuador, and Mexico participated in a roundtable discussion on the Economics of Dialysis and Chronic Kidney Disease in Latin America. The main focus was policy and health care financing. The roundtable promoted open discussion between policymakers and clinicians on how to find viable solutions to contain spending on treatment for end-stage renal disease into the future. A number of options were proposed, including early medical intervention (disease management programs) to slow the progression of chronic kidney disease in high-risk patients, promotion of pre-emptive renal transplantation, and use of the most cost-effective dialysis therapy that can be offered to a patient without compromising outcome. It was concluded that the burden of treating more patients in the future could be alleviated by wider utilization of peritoneal dialysis (PD). However, important changes in health care reimbursement systems and realignment of incentives in the region are required to support wider PD penetration.

Persistent hyperparathyroidism is frequent in postrenal transplant patients. Percutaneous ethanol injection therapy (PEIT) is an alternative for treatment of patients with secondary hyperparathyroidism but it was not described in postrenal transplant patients. We report our experience with PEIT to control hyperparathyroidism in the post-transplant period. We performed PEIT under ultrasonographic guidance and local anesthesia in eight patients because of persistent secondary hyperparathyroidism after renal transplantation. Indications for PEIT were: high intact parathyroid hormone (iPTH) levels with hypercalcemia, hypophosphatemia, osteopenia and/or bone pain. All patients had at least one visible parathyroid nodule by ultrasonography. Biochemical assays were performed immediately before PEIT, between 1 and 7 days after last PEIT, and a mean of 8.0 +/- 2.8 months after PEIT. Serum iPTH and calcium levels decreased significantly after treatment and remained unchanged until final control. Serum iPTH decreased from 286.9 +/- 107.2 to 154.6 +/- 42.2 pg/ml (P < 0.01) after PEIT (percentual reduction 36.5 +/- 9.5%). This response was significantly correlated to total ethanol volume used (r: 0.94, P < 0.0001). Hypercalcemia disappeared in six of eight patients treated. Only minor complications were registered. There were no changes in renal function related to the treatment. Our findings show that PEIT is a useful and safe alternative for patients with persistent post-transplant secondary hyperparathyroidism.

Serum creatinine is an insensitive marker to identify early changes in glomerular filtration rate (GFR), for this reason alternative methods to estimate renal function result of great clinical importance. Forty-one patients were studied using creatinine clearance modified with cimetidina (Clcrc) as surrogate of GFR, cystatin C-based equations (i.e. Larsson and Hoek formulas), Cockroft-Gault and MDRD abbreviated equations. In the whole group, as well as in those patients with serum creatinine < or =1.2 mg/dl--but reduced renal function: Clcrc 62.01 +/- 17.33 ml/ min/1.73 m(2)-, Larsson and Hoek equations showed higher correlations and lower bias than creatinine-based formulas. Abbreviated MDRD equation showed good performance just in those patients with evident alteration of renal function (serum creatinine > 1.2 mg/dl). We concluded that in patients with different stages of renal function, cystatin C-based equations detect reduction of renal function earlier than the serum creatinine-based formulas.

The early urinary tract infection (EUTI) in kidney transplant recipients is an infection develop during the first 3 months post transplant surgery. The effect of EUTI on graft survival and risk factors have been scarcely studied. Our objetives were the evaluation of risk factors to EUTI, the assessment of the causal agent and graft survival impact. A retrospective analysis of kidney transplantation, period 1997-2000 in Hospital Privado-Centro Médico de Córdoba was carried out. There were two groups of patients with (EUTI group) and without EUTI (control group). Cox model was used to analyze risk factors and Kaplan-Meier method for graft survival. A total of 226 consecutive patients received kidney transplantation. In 55 patients (24.3%) EUTI was detected. Risk factors for EUTI were: invasive urological maneuvers (RR = 4.34, CI 95% 1.42-13.21), diabetes mellitus (RR = 3.79, CI 95% 1.42-10.14), cytomegalovirus infection (RR = 2.9, CI 95% 1.02-8.24) and previous transplants (RR = 2.83, CI 95% 1.08-7.45). Delayed graft function was associated with lower incidence of EUTI (RR = 0.38, CI 95% 0.15-0.94). The causal agents were: Klebsiella pneumoniae (36%), Pseudomonas aeruginosa (24%) and Escherichia coli (9%). Graft survival at 2 years was similar in EUTI (87.2%) and control group (81.2%, p = 0.32). This series shows that invasive urological maneuvers were the main risk factors for EUTI. Graft survival was similar. High prevalence of non coli bacteria need further evaluation.

In the present review, we summarize the principles governing the transport of fluid and electrolytes across the peritoneum during continuous ambulatory peritoneal dialysis (CAPD) in "average" patients and during ultrafiltration failure (UFF), according to the three-pore model of peritoneal transport. The UF volume curves as a function of dwell time [V(t)] are determined in their early phase by the glucose osmotic conductance [product of the UF coefficient (LpS) and the glucose reflection coefficient (sigmag)] of the peritoneum; in their middle portion by intraperitoneal volume and glucose diffusivity; and in their late portion by the LpS, Starling forces, and lymph flow. The most common cause of UFF is increased transport of small solutes (glucose) across the peritoneum, whereas the LpS is only moderately affected. Concerning peritoneal ion transport, ions that are already more or less fully equilibrated across the membrane at the start of the dwell, such as Na+ (Cl-), Ca2+, and Mg2+, have a convection-dominated transport. The removal of these ions is proportional to UF volume (approximately 10 mmol/L Na+ and 0.12 mmol/L Ca2+ removed per deciliter UF in 4 hours). The present article examines the impact on fluid and solute transport of varying concentrations of Ca2+ and Na+ in peritoneal dialysis solutions. Particularly, the effect of "ultralow" sodium solutions on transport and UF is simulated and discussed. Ions with high initial concentration gradients across the peritoneum, such as K+, phosphate, and bicarbonate, display a diffusion-dominated transport. The transport of these ions can be adequately described by non-electrolyte equations. However, for ions that are in (or near) their diffusion equilibrium over the peritoneum (Na+, Ca2+, Mg2+), more complex ion transport equations need to be used. Due to the complexity of these equations, however, non-electrolyte transport formalism is commonly employed, which leads to a marked underestimation of mass transfer area coefficients (PS). This can be avoided by determining the PS when transperitoneal ion concentration gradients are steep.

Background: Percutaneous ethanol injection treatment (PEIT) has been proposed as an alternative to surgery for patients with secondary hyperparathyroidism. The present study was undertaken to determine factors that may predict results., Methods: We performed PEIT in 19 patients with secondary hyperparathyroidism refractory to medical therapy under ultrasonographic guidance in an ambulatory facility with local anesthesia. Biochemical assays were performed immediately before the last dialysis session (basal) and between 1 to 7 days after PEIT (post-PEIT)., Results: Serum PTH, calcium, and phosphorus levels decreased significantly after treatment. The percent of change in serum PTH was significantly correlated to total nodular volume (r = 0.73, P = 0.0004), and basal PTH levels (r = 0.48, P = 0.03). Post-PEIT serum phosphate and calcium x phosphate product disclosed negative correlations that were statistically significant with the decrease of PTH levels (r = -0.60, P = 0.009, and r = -0.60, P = 0.01, respectively). The total nodular volume was significantly correlated to the percent change in serum calcium levels (r = 0.60, P = 0.01), in phosphate levels (r = 0.64, P = 0.009), and calcium x phosphate product (r = 0.66, P = 0.01)., Conclusion: Our findings suggest that patients with uncontrolled secondary hyperparathyroidism may benefit from PEIT if they present with very high basal PTH levels and/or big nodule size.