Water-Soluble Vitamins and Trace Elements Losses during On-Line Hemodiafiltration.

Maintenance hemodialysis induces water-soluble vitamins and trace elements losses, which is why recommendations regarding potential supplementation were provided, but mainly based on conventional hemodialysis. This study's aim was to measure the water-soluble vitamins and trace element losses during one on-line post-dilution hemodiafiltration (HDF) session. Thirty-nine patients under maintenance HDF were enrolled. We used the Theraflux® sampler (Theradial Corp., Orvault, France) to analyze the full session dialysate mass transfer. Blood and dialysate samples were collected before and after one HDF session to measure B1, B2, B6, B9, B12, C vitamins, zinc, and selenium concentrations. Values significantly decreased for B1 (20.2%), B2 (13%), B6 (25.4%), B9 (32.6%), C (66.6%) and selenium (6.7%). No significant differences were found for vitamin B12 and zinc. The dialysate losses per session were 1.12 ± 0.88 mg for vitamin B1, 0.28 ± 0.30 mg for B2, 0.33 ± 0.09 mg for B6, 0.3 ± 0.18 mg for B9, 147.5 ± 145.50 mg for C and 25.75 ± 6.91 mg for zinc. Vitamin B12 and selenium were under detection values. In conclusion, during a standard 4hr-HDF session, we found important losses for vitamin B1, B6, B9, C and zinc, suggesting the need for regular monitoring of plasma levels and systematic supplementation of these compounds.

Quantitative histomorphometric analysis of halved iliac crest bone biopsies yield comparable ROD diagnosis as full 7.5mm wide samples.

BACKGROUND AND OBJECTIVES: Histomorphometric analysis of a transiliac bone biopsy is the gold standard for the diagnosis of renal osteodystrophy (ROD). This procedure is costly, invasive and usually performed with a trephine with an internal diameter of 7.5 mm. Our objective was to evaluate the accuracy of ROD diagnosis on halved histological bone sections to determine if they are comparable to the standard 7.5 mm samples. DESIGN: We included 68 bone biopsies performed in CKD patients for diagnostic purposes with a 7.5 mm diameter trephine. Quantitative histomorphometric analysis of the whole bone samples was performed including assessment of bone mineralization, turnover and volume. Each histological section (representing the whole 7.5 mm diameter biopsy) was then divided lengthwise in two hemisections (representing the 3.5 mm diameter biopsy). Histomorphometric analysis was repeated this time on the two hemibiopsies for each sample, blinded from initial results. Diagnoses were classified as osteitis fibrosa, adynamic bone disease, mixed uremic bone disease, osteomalacia or other. Correlations between the whole sample and the hemibiopsies for each parameter were studied. Concordance between the various bone parameters and final ROD diagnosis obtained from the whole section versus the two hemi sections was evaluated. RESULTS: Highly significant correlations were found between parameters measured on the whole section and the corresponding hemisections, with r coefficient of 0.98 for osteoid surface and thickness and bone formation rate, 0.97 for osteoclast surface, and 0.96 for bone volume (p < 0.001). Final diagnosis was in full accordance between the whole biopsy and the two corresponding hemi-biopsies in 91% of cases. CONCLUSIONS: Accurate diagnosis of ROD type was obtained by evaluation of bone surface areas of 3 mm diameter. These data suggest that small invasive bone biopsies might provide accurate ROD diagnostics while decreasing both invasiveness and cost of the procedure.

Aminoglycoside exposure and renal function before lung transplantation in adult cystic fibrosis patients.

Background: Patients with cystic fibrosis (CF) are at risk of kidney injury even before undergoing lung transplantation, because of prolonged exposure to aminoglycosides (AGs), chronic dehydration and complications of diabetes mellitus. The usual equations estimating the glomerular filtration rate (GFR), such as Cockcroft-Gault and Modification of Diet in Renal Disease, are not adapted to the CF population due to patients' low body weight and reduced muscle mass. The aim of this study was to precisely measure GFR in adult CF patients and to see whether repeated AG treatment would impair renal function before lung transplantation. Methods: Inulin or iohexol clearances were performed in 25 adult CF patients when they entered the lung transplant waiting list. No patient was treated with AGs at the time of GFR measurement. Body mass index (BMI), history of diabetes mellitus and blood pressure were recorded. Exposure to intravenous (IV) AGs within 5 years prior to the GFR measurement was obtained from the patient's medical files. Urine samples were collected to check for albuminuria and proteinuria. Results: The population was predominantly female (67%). The mean age was 32 years, the mean BMI was 19 kg/m2 and 28% had CF-related diabetes. Median exposure to IV AG within 5 years before GFR measurement was 155 days with a mean dosage of 7.7mg/kg/day. The mean measured GFR was 106 mL/min/1.73 m2 and the mean estimated GFR according to the Chronic Kidney Disease Epidemiology Collaboration formula was 124 mL/min/1.73 m2. Conclusion: Despite prolonged exposure to high-dose IV AG, no decline in GFR was observed in these patients.