New measurements of energy expenditure and physical activity in chronic kidney disease.

The accurate estimation of total daily energy expenditure (TEE) in chronic kidney patients is essential to allow the provision of nutritional requirements; however, it remains a challenge to collect actual physical activity and resting energy expenditure in maintenance dialysis patients. The direct measurement of TEE by direct calorimetry or doubly labeled water cannot be used easily so that, in clinical practice, TEE is usually estimated from resting energy expenditure and physical activity. Prediction equations may also be used to estimate resting energy expenditure; however, their use has been poorly documented in dialysis patients. Recently, a new system called SenseWear Armband (BodyMedia, Pittsburgh, PA) was developed to assess TEE, but so far no data have been published in chronic kidney disease patients. The aim of this review is to describe new measurements of energy expenditure and physical activity in chronic kidney disease patients.

Giant warts in a kidney transplant patient: regression with sirolimus.

Purpose: Recent reports have suggested that intraabdominal postoperative infection is associated with higher rates of overall and local recurrence and cancer-specific mortality. However, the mechanisms responsible for this association are unknown. We hypothesized that the greater inflammatory response in patients with postoperative intraabdominal infection is associated to an increase in local and systemic angiogenesis. Methods: We designed a prospective cohorts study with matched controls. Patients with postoperative intra-abdominal infection (abscess and/or anastomotic leakage) (group 1; n=17) after elective colorectal cancer resection operated on for cure were compared to patients with an uncomplicated postoperative course (group 2; n=17). IL-6 and VEGF levels were determined by ELISA in serum and peritoneal fluid at baseline, 48 hours and postoperative day 4 or at the time the peritoneal infection occurred. Results: No differences were observed in age, gender, preoperative CEA, tumor stage and location and type of procedure performed. Although there were no differences in serum IL-6 levels at 48 hours, this pro-inflammatory cytokine was higher in group 1 on postoperative day 4 (group 1: 21533 + 27900 vs. group 2: 1130 + 3563 pg/ml; p < 0.001). Serum VEGF levels were higher in group 1 on postoperative day 4 (group 1: 1212 + 1025 vs. group 2: 408 + 407 pg/ml; p < 0.01). Peritoneal fluid VEGF levels were also higher in group 1 at 48 hours (group 1: 4857 + 4384 vs. group 2: 630 + 461 pg/ml; p < 0.001) and postoperative day 4 (group 1: 32807 + 98486 vs. group 2: 1002 + 1229 pg/ml; p < 0.001). A positive correlation between serum IL-6 and VEGF serum levels was observed on postoperative day 4 (r=0.7; p<0.01). Conclusions: These results suggest that not only the inflammatory response but also the angiogenic pathways are stimulated in patients with intra-abdominal infection after surgery for colorectal cancer. The implications of this finding on long-term follow-up need to be evaluated.

La lithiase rénale: un marqueur du risque cardiovasculaire [Kidney stone as a cardiovascular risk marker].

Si le passage d'un calcul rénal est souvent considéré comme un événement médical mineur, quoique très douloureux, de plus en plus d'études indiquent qu'il doit être pris au sérieux puisqu'il peut indiquer un risque cardiovasculaire augmenté. Nous revoyons ici les études qui associent risque cardiovasculaire et calcul rénal et les liens physiopathologiques qui les unissent. Nous montrons que la lithiase est un événement intervenant tôt dans la vie d'un individu à risque de développer des complications cardiovasculaires. Ainsi, la lithiase ne doit pas être banalisée, mais doit être considérée comme une première alerte devant inciter le médecin traitant à recenser précocement les facteurs de risque cardiovasculaires et à mettre en place une stratégie de prévention. Cette approche pourrait permettre de diminuer l'incidence d'événements cardiovasculaires chez les patients formeurs de lithiases. Most of the time, kidney stones are considered as minor, but painful events. However, several studies have recently shown an association between kidney stone and an increased cardio-vascular risk. We review here these studies and explore the underlying pathophysiological hypotheses. At the end, we propose that lithiasis should be considered as a red flag intervening early during life-time and allowing a check of cardiovascular risk factors and early preventive intervention. Such approach may be successful in reducing the incidence of cardio-vascular events in stone formers.

Treatment-dependent loss of polyfunctional CD8+ T-cell responses in HIV-infected kidney transplant recipients is associated with herpesvirus reactivation.

Antiretroviral-therapy has dramatically changed the course of HIV infection and HIV-infected (HIV(+)) individuals are becoming more frequently eligible for solid-organ transplantation. However, only scarce data are available on how immunosuppressive (IS) strategies relate to transplantation outcome and immune function. We determined the impact of transplantation and immune-depleting treatment on CD4+ T-cell counts, HIV-, EBV-, and Cytomegalovirus (CMV)-viral loads and virus-specific T-cell immunity in a 1-year prospective cohort of 27 HIV(+) kidney transplant recipients. While the results show an increasing breadth and magnitude of the herpesvirus-specific cytotoxic T-cell (CTL) response over-time, they also revealed a significant depletion of polyfunctional virus-specific CTL in individuals receiving thymoglobulin as a lymphocyte-depleting treatment. The disappearance of polyfunctional CTL was accompanied by virologic EBV-reactivation events, directly linking the absence of specific polyfunctional CTL to viral reactivation. The data provide first insights into the immune-reserve in HIV+ infected transplant recipients and highlight new immunological effects of thymoglobulin treatment. Long-term studies will be needed to assess the clinical risk associated with thymoglobulin treatment, in particular with regards to EBV-associated lymphoproliferative diseases.

Antidiabetic drugs and kidney disease - Recommendations of the Swiss Society for Endocrinology and Diabetology.

Patients with diabetes are at risk of early renal function decline. Therefore, kidney function needs monitoring at least once per year. Once the glomerular filtration rate (GFR) is less than 60 ml/min, the pharmacokinetics of antidiabetic drugs may be altered. Sulfonylurea and glinide therapies are associated with a risk of hypoglycaemia which is increased in the presence of renal impairment. Most sulfonylureas must be discontinued once GFR is <60 ml/min. Some glinides may be continued beyond this threshold, in particular repaglinide, which may be used in dialysis patients. In the absence of comorbidities, metformin can be continued at lower doses until a GFR of 45 ml/min, but must be withdrawn in case of dehydration or during the administration of a nephrotoxic drug including dye for radiological investigations. Glitazones may worsen water and sodium retention in patients with renal impairment. The pharmacokinetics of all DPP-IV inhibitors except linagliptin are altered with impaired renal function. Only sitagliptin, saxagliptin and linagliptin may be used in advanced kidney disease, but experience is as yet very limited. GLP-1 agonists are contraindicated in moderate to advanced kidney disease.

Purification and characterization of (Na+ + K+)-ATPase from toad kidney

This report describes the partial purification and the characteristics of (Na+ + K+)-ATPase (ATP phosphohydrolase, EC 3.6.1.3) from an amphibian source. Toad kidney microsomes were solubilized with sodium deoxycholate and further purified by sodium dodecyl sulphate treatment and sucrose gradient centrifugation, according to the methods described by Lane et al. [(1973) J. Biol. Chem. 248, 7197--7200], Jørgensen [(1974) Biochim. Biophys. Acta 356, 36--52] and Hayashi et al. [(1977) Biochim. Biophys. Acta 482, 185--196]. (Na+ + K+)-ATPase preparations with specific activities up to 1000 mumol Pi/mg protein per h were obtained. Mg2+-ATPase only accounted for about 2% of the total ATPase activity. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis revealed three major protein bands with molecular weights of 116 000, 62 000 and 26 000. The 116 000 dalton protein was phosphorylated by [gamma-32P]ATP in the presence of sodium but not in the presence of potassium. The 62 000 dalton component stained for glycoproteins. The Km for ATP was 0.40 mM, for Na+ 12.29 mM and for K+ 1.14 mM. The Ki for ouabain was 35 micron. Temperature activation curves showed two activity peaks at 37 degrees C and at 50 degrees C. The break in the Arrhenius plot of activity versus temperature appeared at 15 degrees C.

Management of transitional-cell carcinoma of the renal pelvis and ureter.

Transitional-cell carcinoma of the renal pelvis or ureter is a relatively rare disease. Several risk factors are smoking, occupational carcinogens, analgesic abuse or Balkan nephropathy. The grade and stage of the disease have the most significant impact on the outcome. The treatment of renal pelvis and ureter tumours is open or laparoscopic surgery varying from conservative to more extensive surgical procedures, i.e. radical nephroureterectomy including removal of the contents of Gerota's fascia with ipsilateral ureter and a cuff of bladder at its distal extent. Most available data are from retrospective studies and surgery is the mainstay of treatment. Chemotherapy and/or radiation therapy are possible adjuvant or primary treatment for selected patients; however, prospective studies are needed to confirm their use.

Structural organization of alpha-subunit from purified and microsomal toad kidney (Na+ + K+)-ATPase as assessed by controlled trypsinolysis

The membrane organization of the alpha-subunit of purified (Na+ + K+)-ATPase ((Na+ + K+)-dependent adenosine triphosphate phosphorylase, EC 3.6.1.3) and of the microsomal enzyme of the kidney of the toad Bufo marinus was compared by using controlled trypsinolysis. With both enzyme preparations, digestions performed in the presence of Na+ yielded a 73 kDa fragment and in the presence of K+ a 56 kDa, a 40 kDa and small amounts of a 83 kDa fragment from the 96 kDa alpha-subunit. In contrast to mammalian preparations (Jørgensen, P.L. (1975) Biochim. Biophys. Acta 401, 399-415), trypsinolysis of the purified amphibian enzyme led to a biphasic loss of (Na+ + K+)-ATPase activity in the presence of both Na+ and K+. These data could be correlated with an early rapid cleavage of 3 kDa from the alpha-subunit in both ionic conditions and a slower degradation of the remaining 93 kDa polypeptide. On the other hand, in the microsomal enzyme, a 3 kDa shift of the alpha-subunit could only be produced in the presence of Na+. Our data indicate that (1) purification of the amphibian enzyme with detergent does not influence the overall topology of the alpha-subunit but produces a distinct structural alteration of its N-terminus and (2) the amphibian kidney enzyme responds to cations with similar conformational transitions as the mammalian kidney enzyme. In addition, anti alpha-serum used on digested enzyme samples revealed on immunoblots that the 40 kDa fragment was better recognized than the 56 kDa fragment. It is concluded that the NH2-terminal of the alpha-subunit contains more antigenic sites than the COOH-terminal domain in agreement with the results of Farley et al. (Farley, R.A., Ochoa, G.T. and Kudrow, A. (1986) Am. J. Physiol. 250, C896-C906).

Meta-analysis identifies multiple loci associated with kidney function-related traits in east Asian populations.

Chronic kidney disease (CKD), impairment of kidney function, is a serious public health problem, and the assessment of genetic factors influencing kidney function has substantial clinical relevance. Here, we report a meta-analysis of genome-wide association studies for kidney function-related traits, including 71,149 east Asian individuals from 18 studies in 11 population-, hospital- or family-based cohorts, conducted as part of the Asian Genetic Epidemiology Network (AGEN). Our meta-analysis identified 17 loci newly associated with kidney function-related traits, including the concentrations of blood urea nitrogen, uric acid and serum creatinine and estimated glomerular filtration rate based on serum creatinine levels (eGFRcrea) (P < 5.0 × 10(-8)). We further examined these loci with in silico replication in individuals of European ancestry from the KidneyGen, CKDGen and GUGC consortia, including a combined total of ∼110,347 individuals. We identify pleiotropic associations among these loci with kidney function-related traits and risk of CKD. These findings provide new insights into the genetics of kidney function.

Serum 25-hydroxyvitamin D level and kidney function decline in a Swiss general adult population.

Molecular evidence suggests that levels of vitamin D are associated with kidney function loss. Still, population-based studies are limited and few have considered the potential confounding effect of baseline kidney function. This study evaluated the association of serum 25-hydroxyvitamin D with change in eGFR, rapid eGFR decline, and incidence of CKD and albuminuria. Baseline (2003-2006) and 5.5-year follow-up data from a Swiss adult general population were used to evaluate the association of serum 25-hydroxyvitamin D with change in eGFR, rapid eGFR decline (annual loss >3 ml/min per 1.73 m(2)), and incidence of CKD and albuminuria. Serum 25-hydroxyvitamin D was measured at baseline using liquid chromatography-tandem mass spectrometry. eGFR and albuminuria were collected at baseline and follow-up. Multivariate linear and logistic regression models were used considering potential confounding factors. Among the 4280 people included in the analysis, the mean±SD annual eGFR change was -0.57±1.78 ml/min per 1.73 m(2), and 287 (6.7%) participants presented rapid eGFR decline. Before adjustment for baseline eGFR, baseline 25-hydroxyvitamin D level was associated with both mean annual eGFR change and risk of rapid eGFR decline, independently of baseline albuminuria. Once adjusted for baseline eGFR, associations were no longer significant. For every 10 ng/ml higher baseline 25-hydroxyvitamin D, the adjusted mean annual eGFR change was -0.005 ml/min per 1.73 m(2) (95% confidence interval, -0.063 to 0.053; P=0.87) and the risk of rapid eGFR decline was null (odds ratio, 0.93; 95% confidence interval, 0.79 to 1.08; P=0.33). Baseline 25-hydroxyvitamin D level was not associated with incidence of CKD or albuminuria. The association of 25-hydroxyvitamin D with eGFR decline is confounded by baseline eGFR. Sufficient 25-hydroxyvitamin D levels do not seem to protect from eGFR decline independently from baseline eGFR.

Chronic kidney disease in type 2 diabetic patients followed-up by primary care physicians in Switzerland: prevalence and prescription of antidiabetic drugs.

QUESTION UNDER STUDY: The aim of this study was to assess the prevalence of chronic kidney disease (CKD) among type 2 diabetic patients in primary care settings in Switzerland, and to analyse the prescription of antidiabetic drugs in CKD according to the prevailing recommendations. METHODS: In this cross-sectional study, each participating physician was asked to introduce anonymously in a web database the data from up to 15 consecutive diabetic patients attending her/his office between December 2013 and June 2014. Demographic, clinical and biochemical data were analysed. CKD was classified with the KDIGO nomenclature based on estimated glomerular filtration rate (eGFR) and urinary albumin/creatinine ratio. RESULTS: A total of 1 359 patients (mean age 66.5 ± 12.4 years) were included by 109 primary care physicians. CKD stages 3a, 3b and 4 were present in 13.9%, 6.1%, and 2.4% of patients, respectively. Only 30.6% of patients had an entry for urinary albumin/creatinine ratio. Among them, 35.6% were in CKD stage A2, and 4.1% in stage A3. Despite prevailing limitations, metformin and sulfonylureas were prescribed in 53.9% and 16.5%, respectively, of patients with advanced CKD (eGFR <30 ml/min). More than a third of patients were on a dipeptidyl-peptidase-4 inhibitor across all CKD stages. Insulin use increased progressively from 26.8% in CKD stage 1-2 to 50% in stage 4. CONCLUSIONS: CKD is frequent in patients with type 2 diabetes attending Swiss primary care practices, with CKD stage 3 and 4 affecting 22.4% of cases. This emphasizes the importance of routine screening of diabetic nephropathy based on both eGFR and urinary albumin/creatinine ratio, the latter being largely underused by primary care physicians. A careful individual drug risk/benefit balance assessment is mandatory to avoid the frequently observed inappropriate prescription of antidiabetic drugs in CKD patients.

Clinically-relevant threshold of preformed donor-specific anti-HLA antibodies in kidney transplantation.

BACKGROUND: Pretransplant anti-HLA donor-specific antibodies (DSA) are recognized as a risk factor for acute antibody-mediated rejection (AMR) in kidney transplantation. The predictive value of C4d-fixing capability by DSA or of IgG DSA subclasses for acute AMR in the pretransplant setting has been recently studied. In addition DSA strength assessed by mean fluorescence intensity (MFI) may improve risk stratification. We aimed to analyze the relevance of preformed DSA and of DSA MFI values. METHODS: 280 consecutive patients with negative complement-dependent cytotoxicity crossmatches received a kidney transplant between 01/2008 and 03/2014. Sera were screened for the presence of DSA with a solid-phase assays on a Luminex flow analyzer, and the results were correlated with biopsy-proven acute AMR in the first year and survival. RESULTS: Pretransplant anti-HLA antibodies were present in 72 patients (25.7%) and 24 (8.6%) had DSA. There were 46 (16.4%) acute rejection episodes, 32 (11.4%) being cellular and 14 (5.0%) AMR. The incidence of acute AMR was higher in patients with pretransplant DSA (41.7%) than in those without (1.6%) (p<0.001). The median cumulative MFI (cMFI) of the group DSA+/AMR+ was 5680 vs 2208 in DSA+/AMR- (p=0.058). With univariate logistic regression a threshold value of 5280 cMFI was predictive for acute AMR. DSA cMFI's ability to predict AMR was also explored by ROC analysis. AUC was 0.728 and the best threshold was a cMFI of 4340. Importantly pretransplant DSA>5280 cMFI had a detrimental effect on 5-year graft survival. CONCLUSIONS: Preformed DSA cMFI values were clinically-relevant for the prediction of acute AMR and graft survival in kidney transplantation. A threshold of 4300-5300 cMFI was a significant outcome predictor.