Circulating 20S proteasome for assessing protein energy wasting syndrome in hemodialysis patients.

Protein energy wasting (PEW) including muscle atrophy is a common complication in chronic hemodialysis patients. The ubiquitin proteasome system (UPS) is the main proteolytic system causing muscle atrophy in chronic kidney disease and proteasome 20S is the catalytic component of the UPS. Circulating proteasome 20S (c20S proteasome) is present in the blood and its level is related to disease severity and prognosis in several disorders. We hypothesized that c20S proteasome could be related with muscle mass, other PEW criteria and their evolution in hemodialysis patients. Stable hemodialysis patients treated at our center for more than 3 months were followed over 2 years. C20S proteasome assay was performed at baseline. Biological and clinical data were collected, muscle mass was assessed by multi-frequency bio-impedancemetry, and nutritional scores were calculated at baseline, 1 year and 2 years. Hospitalizations and mortality data were collected over the 2 years. Forty-nine patients were included. At baseline, the c20S proteasome level was 0.40[0.26-0.55] µg/ml. Low muscle mass as defined by a lean tissue index (LTI) < 10th in accordance with the International Society of Renal Nutrition and Metabolism guidelines was observed in 36% and PEW in 62%. Increased c20S proteasome levels were related with LTI at baseline (R = 0.43, p = 0.004) and with its 2 year-variation (R = -0.56, p = 0.003). Two-year survival rate was not different between higher and lower c20S proteasome values (78.9 vs 78.4%, p = 0.98 log-rank test). C20S proteasome is not a good marker for assessing nutritional status in hemodialysis patients and predicting patient outcomes.

Predictors of Autogenous Arteriovenous Hemodialysis Access Thrombosis after Renal Transplantation.

BACKGROUND: The fate of autogenous arteriovenous fistula (aAVF) after renal transplantation (RT) remains variable. The aim of this study was to determine the predictors for their thrombosis after RT. METHODS: We conducted a monocentric retrospective review of prospective clinical records of 145 patients with a functional aAVF who had an RT between January 2004 and December 2009 in the University Hospital of Clermont-Ferrand. Our primary end point was the thrombosis of the aAVF. Univariate and multiple logistic regression analyses were used to identify risk factors associated to aAVF thrombosis after RT. RESULTS: There were 105 men (72%) and 40 women (28%), mean age 52 years (range: 18.4-74.7 years). The aAVF was created on average 40 months (range: 2-169) before the RT. The aAVF was distal in 96 cases (66%) and proximal in 49 cases (34%). Nineteen aAVF (13.1%) were complicated and required an endovascular or surgical repair before RT. Forty-nine patients (34%) required multiple aAVF (>2). Mean follow-up from RT was 58 months (range: 1 day-123 months) and from aAVF creation 97 months (range: 5-262 months). At the end of the follow-up, 81 aAVFs (59%) were patent, 42 (29%) were thrombosed, and 22 (15%) were surgically closed. Patients that had multiple fistulas before RT and active smokers were significantly at risk to thrombose their aAVF after the RT in univariate (P = 0.03 and P = 0.02, respectively) and multiple logistic regression analyses (P = 0.03 and P = 0.047, respectively). CONCLUSIONS: Thrombosis is a part of the natural history of the aAVF after RT. A history of multiple aAVF creations before RT and active smoking were associated to significant increased risk for fistula thrombosis. Because hemodialysis may be needed after RT, the aAVF patency should be preserved, excepted when the aAVF resulted in complications. Follow-up of the aAVF after RT is important to detect and treat complications before thrombosis occurs.

Fermentable carbohydrate supplementation alters nitrogen excretion in chronic renal failure.

BACKGROUND: Considerable attention has been given to the impact of nutrition on kidney disease. Most dietary attempts to treat chronic renal failure (CRF) and to decrease uremia use a protein restriction. An alternative dietetic approach based on fermentable carbohydrate (FC) supplementation of the diet could lead to the same urea-lowering effect by increasing urea nitrogen (N) excretion in stool, with a concomitant decrease of the total N quantity excreted in urine. METHODS: In the present prospective study, the impact of FC (40 g/d) on uremia and on N excretion routes was investigated during 5 weeks in nine CRF patients in the presence of a moderated restrictive protein diet (0.8 g/kg/d). Patients were their own controls and were treated by the cross-over method after randomization (5 weeks with FC versus 5 weeks without FC). RESULTS: Feeding FC significantly increased the quantity of N excreted in stool from 2.1 +/- 0.8 to 3.2 +/- 1.1 g/d (+51%) (P < .01) and decreased, in parallel, the urinary N excretion from 9.4 +/- 1.7 to 8.3 +/- 1.4 g/d (-12%) (P < .01). The total N quantities excreted by the two routes were unchanged by the FC, which shows that the FC was efficient to shift N excretion from the urinary route toward the digestive route. As a result of the increase of urea transfer into the colon, the plasma urea concentration was significantly decreased from 26.1 +/- 8.7 to 20.2 +/- 8.2 mmol/L (-23%) (P < .05). CONCLUSIONS: These results show the same beneficial effects in CRF as those obtained with a restrictive protein diet without its nutritional drawbacks. This should be confirmed by other prospective works over a longer duration and a larger number of patients to study the effects of FC on CRF progression and on CRF terminal stage tolerance.