End-proximal tubule phosphate concentration increases as GFR falls in humans: measurement by means of a lithium clearance-based methodology.

BACKGROUND: Microscopic nephrocalcinosis secondary to intratubular calcium phosphate (CaP) precipitation is thought to accelerate progression to end-stage renal failure in chronic kidney diseases. In phosphorus (P)-loaded uninephrectomized rats, intratubular CaP crystal formation and progressive tubular damage occurred when end-proximal tubule P concentration (ePTpc) increased above a threshold level. METHODS: We have calculated ePTpc in humans by urine P and creatinine concentration, with the end-proximal tubule fluid volume calculated either as lithium (Li) clearance (ePTpc-Li) or as a fixed 0.7 fraction of glomerular filtration rate (GFR), as published (ePTpc-70). Healthy people undergoing living transplant kidney donation before (DON-pre, n = 70) and after (DON-post, n = 64) nephrectomy and 25 patients with stage 2-5 CKD were investigated while on regular free diet. RESULTS: ePTpc showed a stepwise increase with decreasing functional renal mass (DON-pre 2.51 ± 0.99 and 1.56 ± 0.47 mg/dL for ePTpc-Li and -70 calculation, respectively; DON-post 3.43 ± 1.14 and 2.18 ± 0.44;  CKD 5.68 ± 3.30 and 3.00 ± 1.30, P < .001 for all); ePTpc was inversely correlated with Ccr and directly with PTH, fractional P excretion and excretion (UpV) corrected for GFR (P < .001 for all), but not with Pp. ePTpc-Li and ePTpc-70 were significantly correlated (r = 0.62, P < .001), but ePTpc-70 was lower than the corresponding ePTpc-Li. Levels of ePTpc increased above a suggested dangerous threshold when daily UpV/GFR was higher than about 10 mg/mLCcr. CONCLUSIONS: ePTpc progressively increases in humans as functional renal mass falls independently from plasma P levels. Main determinants of ePTpc rise are GFR fall, degree of phosphaturia per unit GFR and P intake corrected for GFR. It may become a novel, potentially useful, indicator to guide management of CKD patients.

An enigmatic case of IgG4-related nephropathy and an updated review of the literature.

IgG4-related disease (IgG4-RD) is still an underestimated disorder which affects multiple organs, and its recognition as a distinct clinical disease has been only proved in the recent decades. The renal involvement has been documented in approximately 15% of patients with IgG4-RD, and the typical manifestation is a tubulo-interstitial nephritis. The main histological findings in IgG4-RD are typically a dense tissue infiltration of IgG4-positive plasma cells, storiform fibrosis, obliterative phlebitis, and frequently elevated IgG4 serum levels. Herein we report our atypical and peculiar clinical presentation of an IgG4-related nephropathy (IgG4-RN) and the remarkable response to rituximab (RTX) treatment at the renal imaging with computerized tomography assessment. The current nephrological evidences support the renal function recovery after steroids or steroids plus RTX therapy, even if the renal imaging data are not always shown. In a complex and enigmatic clinical scenario such as the IgG4-RN, both the renal biopsy and the renal imaging before and after the immunosuppressive therapy become mandatory tools to thoroughly define the diagnosis, the management and the response to the immunological therapy.

Single Session and Weekly Beta 2-Microglobulin Removal with Different Dialytic Procedures: Comparison between High-Flux Standard Bicarbonate Hemodialysis, Post-Dilution Hemodiafiltration, Short Frequent Hemodialysis with NxStage Technology and Automated Peritoneal Dialysis.

BACKGROUND: NxStage System One cycler (NSO) is a widespread system for home daily dialysis. Few data are available on the impact of this "low dialysate volumes system" on the removal rate of poorly diffusible, time-dependent solutes like ß2-microglobulin (ß2M). METHODS: Single-session and weekly balances of ß2M were performed and compared in 12 patients on daily NSO, 13 patients on standard high-flux bicarbonate dialysis (BHD), 5 patients on standard post-dilution on line hemodiafiltration (HDF), and 13 patients on automated peritoneal dialysis (APD). RESULTS: Intradialytic fall of plasma water ß2M levels (corrected for rebound) was 65.2 ± 2.6% in HDF, 49.8 ± 9.1% in BHD, and 32.3 ± 6.4% in NSO (p < 0.001 between all groups). Single treatment dialysate removal was much less in APD (19.4 ± 20.4 mg, p < 0.001) than in any extracorporeal technologies, and was less in NSO (126.2 ± 35.6 mg, p < 0.001) than in BHD (204.9 ± 53.4 mg) and HDF (181.9 ± 37.6 mg), with no differences between the latter 2; however weekly removal was higher in NSO (757.3 ± 213.7 mg, p < 0.04) than in BHD (614.8 ± 160.3 mg) and HDF (545.8 ± 112.8 mg). Extrapolated ß2M adsorption to the membrane was negligible in BHD, 14.7 ± 9.5% of total removal in HDF and 18.3 ± 18.5% in NSO. Integration of single session data into a weekly efficiency indicator (K × t) showed total volume of plasma cleared in NSO (33.4 ± 7.7 L/week) to be higher than in BHD (26.9 ± 7.2 L/week, p < 0.01) and not different than in HDF (36.2 ± 4.7 L/week); it was negligible (3.2 ± 1.0) in APD. CONCLUSIONS: Weekly ß2M removal efficiency proved equal and highest in HDF and NSO (at a 6/week prescription), slightly lesser in BHD and lowest in APD.

Renal Transplants from Older Deceased Donors: Use of Preimplantation Biopsy and Differential Allocation to Dual or Single Kidney Transplant according to Histological Score Has No Advantages over Allocation to Single Kidney Transplant by Simple Clinical Indication.

BACKGROUND: Grafts from elderly donors (ECD) are increasingly allocated to single (SKT) or dual (DKT) kidney transplantation according to biopsy score. Indications and benefits of either procedure lack universal agreement. METHODS: A total of 302 ECD-transplants in period from Jan 1, 2000, to Dec 31, 2015, were allocated to SKT (SKTpre) on clinical grounds alone (before Dec 2010, pre-DKT era, n = 170) or according to a clinical-histological protocol (after Dec 2010, DKT era, n = 132) to DKT (n = 48), SKT biopsy-based protocol ("high-risk", SKThr, n = 51), or SKT clinically based protocol ("low-risk", SKTlr, n = 33). Graft and patient survival were compared between the two periods and between different transplant categories. RESULTS: Graft and overall survival in recipients from ECD in pre-DKT and DKT era did not differ (5-year graft survival 87.7% and 84.2%, resp.); equal survival in the 2 ECD periods was shown in both donor age ranges of 60-69 and >70-years, and in low-risk or high-risk ECD categories. Within the DKT protocol SKThr showed worst graft and overall survival in the 60-69 donor age range; DKT did not result in significantly better outcome than SKT from ECD in either era. One-year posttransplant creatinine clearance in recipients did not differ between any ECD transplant category. At 3 and 5 years after transplantation there were significantly higher total dialysis-free recipient life years from an equal donor number in the pre-DKT era than in the DKT protocol. CONCLUSIONS: Use of a biopsy-based protocol to allocate grafts from aged donors to SKT or DKT did not result in better short term graft survival than a clinically based protocol with allocation only to SKT and reduced overall recipient dialysis-free life years in time.

Oxaliplatin Immune-Induced Syndrome Occurs With Cumulative Administration and Rechallenge: Single Institution Series and Systematic Review Study.

Oxaliplatin immune-induced syndrome (OIIS) is an uncommon, potentially life-threatening, side effect associated with oxaliplatin-based chemotherapy. The present study reports 5 original cases of OIIS and systematically reviewed the available published cases. We retrospectively analyzed the clinical archives of the Niguarda Cancer Center from 2009 to 2015 and conducted a search for OIIS using the PubMed database, followed by deeper investigation of the references of the recorded studies. We pooled our series with other reported cases for systematic review in accordance with the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement using only English language as the selection criterion. A total of 61 OIIS cases were analyzed, the largest series reported to date. Of the 61 patients, 56 (91.8%) had received oxaliplatin for metastatic colorectal cancer. In 32 of the 61 patients (52.5%), OIIS was associated with grade 4 thrombocytopenia and in 4 (6.6%) with grade 4 anemia. OIIS was fatal in 4 patients. In 49 patients, oxaliplatin-induced immune system activation was tested using the Coombs test or by detection of antiplatelet antibodies and was positive in 87.7% of the patients. The average number of oxaliplatin cycles until the onset of OIIS was 16.7, and the number was significantly lower when oxaliplatin was administered as a rechallenge after a period of vacancy of treatment with this agent (4.6 cycles as rechallenge vs. 13.6 as first-time exposure; P < .00001). OIIS is triggered by cumulative administration of oxaliplatin, characteristically with a threefold earlier onset when the drug is administered as a rechallenge. Prompt identification of OIIS can be expected to reduce the risk of iatrogenic morbidity and mortality.

Chronic hypercalcaemia from inactivating mutations of vitamin D 24-hydroxylase (CYP24A1): implications for mineral metabolism changes in chronic renal failure.

BACKGROUND: Loss-of-function mutations of vitamin D-24 hydroxylase have recently been recognized as a cause of hypercalcaemia and nephrocalcinosis/nephrolithiasis in infants and adults. True prevalence and natural history of this condition are still to be defined. METHODS: We describe two adult patients with homozygous mutations and six related heterozygous carriers. Mineral and hormonal data in these patients were compared with that in 27 patients with stage 2-3 chronic kidney disease and 39 healthy adult kidney donors. RESULTS: Probands had recurrent nephrolithiasis, chronic hypercalcaemia with depressed parathyroid hormone (PTH) and increased 1,25(OH)(2)D levels; carriers had nephrolithiasis (two of six), hypercalciuria (two of six) and high or normal-high 1,25(OH)(2)D (four of four). Corticosteroids did not reduce plasma and urine calcium levels, but ketoconazole did, indicating that 1,25(OH)(2)D production is not maximally depressed despite coexisting hypercalcaemia, high 1,25(OH)(2)D and depressed PTH, and that 1,25(OH)(2)D degradation through vitamin D-24 hydroxylase is a regulator of plasma 1,25(OH)(2)D levels. Both probands had vascular calcifications and high bone mineral content. One developed stage 3b renal failure: in this patient 1,25(OH)(2)D decreased within normal limits as glomerular filtration rate (GFR) fell and PTH rose to high-normal values, yet hypercalcaemia persisted and the ratio of 1,25(OH)(2)D to GFR remained higher than normal for any degree of GFR. CONCLUSIONS: This natural model indicates that vitamin D-24 hydroxylase is a key physiologic regulator of calcitriol and plasma calcium levels, and that balanced reduction of 1,25(OH)(2)D and GFR is instrumental for the maintenance of physiologic calcium levels and balance in chronic kidney diseases.

Interventions for treating sexual dysfunction in patients with chronic kidney disease.

BACKGROUND: Sexual dysfunction is very common in patients with chronic kidney disease (CKD), but it is still significantly understudied. Treatment options exist but concerns have been raised relating to their efficacy and safety in CKD. OBJECTIVES: We assessed the benefits and harms of existing interventions for treatment of sexual dysfunction in patients with CKD. SEARCH STRATEGY: In October 2010 we searched the Cochrane Renal Group's specialised register, CENTRAL (The Cochrane Library, issue 10), MEDLINE (from 1966) and EMBASE (from 1980). SELECTION CRITERIA: Randomised controlled trials (RCTs) and quasi-RCTs of any pharmacological and non-pharmacological interventions used to treat sexual dysfunction in male and female CKD patients (predialysis, dialysis and kidney transplant) were included. DATA COLLECTION AND ANALYSIS: Two authors independently selected eligible studies, extracted data and assessed study quality. Disagreements were resolved in consultation with an arbitrator. Treatment effects were summarised as risk ratios (RR), mean differences (MD) or standardised mean difference (SMD) with 95% confidence intervals (CI) using a random-effects model. MAIN RESULTS: Fifteen studies (8 parallel, 7 crossover; 352 patients) were included. Only one study enrolled women. Studies evaluated the effects of phosphodiesterase-5 inhibitors (PDE5i), zinc, vitamin E, vitamin D or bromocriptine compared to placebo. PDE5i significantly increased the overall International Index of Erectile Function-5 (IIEF-5) score (2 studies, 101 patients, MD 10.65, 95% CI 5.34 to 15.96), all its individual domains and the complete 15-item IIEF tool (1 study, 41 patients, MD 2.64, 95% CI 1.32 to 3.96). End of treatment testosterone levels were not significantly increased by addition of zinc to dialysate (2 studies, 22 patients, MD 0.21 ng/mL, 95% CI -2.14 to 2.55) but oral zinc improved end of treatment testosterone levels (1 study, 20 patients, SMD 1.62, 95% CI 0.58 to 2.66). There was no difference in plasma luteinizing and follicle-stimulating hormone levels at the end of the study period with zinc therapy. Only sparse data were available for vitamin E, bromocriptine and dihydroxycholecalciferol in CKD patients and there were no studies of intracavernous injections, transurethral injections, mechanical devices or psychosexual therapies in people with CKD. AUTHORS' CONCLUSIONS: PDE5i and zinc are promising interventions for treating sexual dysfunction in men with CKD. Evidence supporting their routine use in CKD patients is limited. There is an unmet need for studying interventions for both male and female sexual dysfunction in CKD, considering the significant disease burden.

Prevalence and correlates of self-reported sexual dysfunction in CKD: a meta-analysis of observational studies.

BACKGROUND: Sexual dysfunction is an under-recognized problem in men and women with chronic kidney disease (CKD). The prevalence, correlates, and predictors of this condition in patients with CKD have not been evaluated comprehensively. STUDY DESIGN: Systematic review and meta-analysis. SETTING & POPULATION: Patients treated using dialysis (dialysis patients), patients treated using transplant (transplant recipients), and patients with CKD not treated using dialysis or transplant (nondialysis nontransplant patients with CKD). SELECTION CRITERIA FOR STUDIES: Observational studies conducted in patients with CKD only or including a control group without CKD. PREDICTOR: Type of study population. OUTCOMES: Sexual dysfunction in men and women with CKD using validated tools, such as the International Index of Erectile Function, the Female Sexual Function Index (FSFI), or other measures as reported by study investigators. RESULTS: 50 studies (8,343 patients) of variable size (range, 16-1,023 patients) were included in this review. Almost all studies explored sexual dysfunction in men and specifically erectile dysfunction. The summary estimate of erectile dysfunction in men with CKD was 70% (95% CI, 62%-77%; 21 studies, 4,389 patients). Differences in reported prevalence rates of erectile dysfunction between different studies were attributable primarily to age, study populations, and type of study tool used to assess the presence of erectile dysfunction. In women, the reported prevalence of sexual dysfunction was assessed in only 306 patients from 2 studies and ranged from 30%-80%. Compared with the general population, women with CKD had a significantly lower overall FSFI score (8 studies or subgroups, 407 patients; mean difference, -9.28; 95% CI, -12.92 to -5.64). Increasing age, diabetes mellitus, and depression consistently were found to correlate with sexual dysfunction in 20 individual studies of patients with CKD using different methods. LIMITATIONS: Suboptimal and lack of uniform assessment of outcome measures. CONCLUSIONS: Sexual dysfunction is highly prevalent in both men and women with CKD, especially among those on dialysis. Larger studies enrolling different ethnic groups, using validated study tools, and analyzing the influence of various factors on the development of sexual dysfunction are needed.

Treatment options for sexual dysfunction in patients with chronic kidney disease: a systematic review of randomized controlled trials.

BACKGROUND AND OBJECTIVES: Sexual dysfunction is very common in patients with chronic kidney disease (CKD), but treatment options are limited. The benefits and harms of existing interventions for treatment of sexual dysfunction were assessed in patients with CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: MEDLINE (1966 to December 2008), EMBASE (1980 to December 2008), and the Cochrane Trial Registry (Issue 4 2008) were searched for parallel and crossover randomized and quasi-randomized trials. Treatment effects were summarized as mean differences (MD) or standardized mean difference (SMD) with 95% confidence intervals (CI) using a random effects model. RESULTS: Fourteen trials (328 patients) were included. Phosphodiesterase-5 inhibitors (PDE5i) compared with placebo significantly increased the overall International Index of Erectile Function-5 (IIEF-5) score (three trials, 101 patients, MD 1.81, 95% CI 1.51 to 2.10), all of its individual domains, and the complete 15-item IIEF-5 (two trials, 80 patients, MD 10.64, 95% CI 5.32 to 15.96). End-of-treatment testosterone levels were not significantly increased by addition of zinc to dialysate (two trials, 22 patients, SMD 0.19 ng/dl, 95% CI -2.12 to 2.50), but oral zinc improved end-of-treatment testosterone levels. There was no difference in plasma luteinizing and follicle-stimulating hormone level at the end of the study period with zinc therapy. CONCLUSIONS: PDE5i and zinc are promising interventions for treating sexual dysfunction in CKD. Evidence supporting their routine use in CKD patients is limited. There is an unmet need for studying interventions for male and female sexual dysfunction in CKD considering the significant disease burden.

Persistent renal hypertrophy and faster decline of glomerular filtration rate precede the development of microalbuminuria in type 1 diabetes.

Soon after the onset of type 1 diabetes, renal hypertrophy and hyperfiltration become manifest, particularly among patients who will subsequently develop diabetic nephropathy. Whether these early renal dysfunctions are involved in the pathogenesis of diabetic nephropathy is currently unclear. We evaluated, during the same day, kidney volume and glomerular filtration rate (GFR) in 146 patients with type 1 diabetes and normal renal function. All the individuals were then monitored for a mean of 9.5 +/- 4.4 years for the development of microalbuminuria. Kidney volume and GFR were reevaluated in a subset of 68 patients 4 years after baseline. During follow-up, microalbuminuria developed in 27 of 146 diabetic patients. At baseline, kidney volume (312.8 +/- 52.6 vs. 281.4 +/- 46.1 vs. 236.8 +/- 41.6 ml/1.73 m(2), P < 0.05) but not GFR was increased in patients predisposed to microalbuminuria. Risk of progression was higher in patients with increased kidney volume (P = 0.0058). Patients predisposed to microalbuminuria showed a stable increase in kidney volume (P = 0.003), along with a faster decline of GFR (P = 0.01). Persistent renal hypertrophy and faster decline of GFR precede the development of microalbuminuria in type 1 diabetes. These findings support the hypothesis that renal hypertrophy precedes hyperfiltration during the development of diabetic nephropathy.

Antihypertensive agents in patients with diabetes: trade-off between renal and cardiovascular protection.

PURPOSE: Management of hypertension in patients with diabetes should address both renal and cardiovascular protection. The use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) for control of hypertension in patients with diabetic nephropathy is widely advocated by various international guidelines. Use of any agent that provides tight control of blood pressure is indicated in patients with diabetes but without nephropathy. METHODS: In this article, the authors present a clinical case scenario and review current clinical evidence supporting the use of ACE inhibitors and ARBs in patients with diabetic nephropathy. In addition, the use of ACE and ARBs in patients with diabetes but without nephropathy will be discussed. RESULTS: Available trial evidence confirms the survival benefits of patients taking ACE inhibitors with diabetic nephropathy. However, the efficacy of ARB inhibitors on survival is unknown. In patients with diabetes without nephropathy, only ACE inhibitors have been found to reduce the risk of onset of microalbuminuria, while all agents affect survival provided a tight control of blood pressure is monitored. CONCLUSIONS: Dose of ACE inhibitors should be titrated appropriately to obtain proven benefits. In summary, current evidence supports the use of ACE inhibitors in patients with and without nephropathy because of renal and cardiovascular benefits.