Background and objectives: Transplantation should favorably affect coronary calcification (CAC) progression in dialysis; however, changes in CAC score in the individual patient are not reliably evaluated.Design, setting, participants & measurements: The authors used special tables of reproducibility limits for each score level to study, by multislice computed tomography and biochemistries, the 2-year changes in CAC in 41 transplant patients (age 48 ؎ 13 yr, 25 men, dialysis vintage 4.8 ؎ 4.3 yr, underwent transplant 6.2 ؎ 5.5 yr prior). Thirty balanced dialysis patients served as controls.Results: In the study group, Agatston score was stable, and C-reactive protein decreased, whereas fetuin and osteoprotegerin increased. In the control group, Agatston score increased, parathyroid hormone and phosphate decreased, and inflammation markers were persistently twice as high as in the study group. With regard to individual changes, 12.2% transplant patients worsened, compared with 56.6% of patients in dialysis (P < 0.0001). Patients without calcification at entry showed slower progression in transplantation (8.3%) than in dialysis (44.4%; P < 0.034), and the difference was similar to that observed in cases with CAC (17.6% versus 61.9%; P < 0.007). Discriminant analysis indicated parathyroid hormone, the modality of therapy (dialysis or transplantation), and erythrocyte sedimentation rate as the variables most associated with worsening.Conclusions: Renal transplantation lowers but does not halt CAC progression. Inflammation and hyperparathyroidism are associated with progression in the populations studied.

Transmembrane α-Klotho (TM-Klotho), expressed in renal tubules, is a cofactor for FGF23-receptor. Circulating soluble-α-Klotho (s-Klotho) results from TM-Klotho shedding and acts on Phosphate (P) and Calcium (Ca) tubular transport. Decreased TM-Klotho, described in experimental chronic kidney disease (CKD), prevents actions of FGF23 and lessens circulating s-Klotho. Thus, levels of s-Klotho could represent a marker of CKD-MBD. To evaluate the clinical significance of s-Klotho in CKD we assayed serum s-Klotho and serum FGF23 in 68 patients (age 58 ± 15; eGFR 45 ± 21 mL/min). s-Klotho was lower than normal (519 ± 183 versus 845 ± 330 pg/mL, P < .0001) in renal patients and its reduction was detectable since CKD stage 2 (P < .01). s-Klotho correlated positively with eGFR and serum calcium (Cas) and negatively with serum phosphate (Ps), PTH and FGF23. FGF23 was higher than normal (73 ± 51 versus 36 ± 11, P < .0002) with significantly increased levels since CKD stage 2 (P < .001). Our data indicate a negative effect of renal disease on circulating s-Klotho starting very early in CKD. Assuming that s-Klotho mirrors TM-Klotho synthesis, low circulating s-Klotho seems to reflect the ensuing of tubular resistance to FGF23, which, accordingly, is increased. We endorse s-Klotho as an early marker of CKD-MBD.

BackgroundCalcifediol (25D) availability is crucial for calcitriol (1,25D) synthesis, but regulation of vitamin D hydroxylases is majorly responsible for 1,25D synthesis. The net efficiency of vitamin D hydroxylases might be informative. We assume that the ratio between calcitriol and calcifediol (25D/1,25D) serum concentrations could suggest the vitamin D hydroxylation efficiency.MethodsWe evaluated 25D/1,25D in different patient populations: hemodialysis (HD, n = 76), CKD stage 2–5 (n = 111), renal transplant (TX, n = 135), patients with no renal disease (No-CKD, n = 290), and primary hyperparathyroidism (PHP, n = 20).ResultsThe geometric mean of 1,25D/25D (pg/ng) averaged 1.11 (HD), 1.36 (CKD), 1.77 (TX), 2.22 (No-CKD), and 4.11 (PHP), with a progressive increment from HD to PHP (p-value for the trend <0.001). Each clinical condition elicited a significant effect on 25D/1,25D (p < 0.0001) and adjusted multivariate analysis indicated levels of Cas, Ps, PTH, and 25D as predictors of 25D/1,25D. Both in vitamin D deficient and replete subjects (25D< or ≥20 ng/ml) 25D/1,25D associated with each clinical condition (p < 0.0001) and mean values increased progressively from HD to PHP (p-values for the trend <0.0001). Regression analysis between 25D (substrate) and 25D/1,25D (efficiency) revealed an exponential negative correlation in No-CKD (r2Exp = 0.53, p < 0.001) with sharp increments of 25D/1,25D when 25D values are <20 ng/ml. At variance, in CKD (r2lin = 0.19) and in TX (r2lin = 0.32) the regression was linear as if, in case of deficit, some inhibition of the system were operating.Conclusion and General significanceIn conclusion 1,25D/25D can reflect the efficiency of vitamin D hydroxylases more than separate evaluation of 25D and 1,25D and can facilitate the therapeutic choices in different patient populations.

HD tissue hypoxia associates with organ dysfunctions. OER, the ratio between SaO2 and central-venous-oxygen-saturation, could estimate oxygen requirements during sessions, but no data are available. We evaluated OER behavior in 20 HD patients with permanent central venous catheter (CVC) as vascular access. Pre-HD OER (33.6 ± 1.4%; M ± SE) was higher than normal (range 20–30%). HD sessions increased OER to 39.2 ± 1.5% (M ± SE; p < 0.05) by 30′ and to 47.4 ± 1.5% (M ± SE; p < 0.001) by end of treatment (delta 40%). During HD sessions of the long and short interdialytic intervals, OER values overlapped, suggesting no influence of patient’s hydration status shifts. OER increased (p < 0.05) after 30′ of isolated HD (zero ultrafiltration), but not during isolated ultrafiltration (zero dialysate flow), suggesting a role for blood-membrane-dialysate interaction, independent of volume reduction. In ten patients, individual variability of pre-HD OER was low and repeatable (maximum calculated difference over time 6.6%), and negatively correlated with HD-induced OER increments (r = 0.860; p < 0.005), suggesting a decline in the adaptive response along with resting OER increments. In 30 prevalent patients, adjusted multivariate analysis showed that pre-HD OER (HR = 0.88, CI 0.79–0.99, p = 0.028) and percent HD-induced OER (HR = 1.04, CI 1.01–1.08, p = 0.015) were both associated with mortality, with threshold values respectively <32% and >40%. In HD patients with CVC as vascular access, OER is a cheap, easily measurable and repeatable parameter useful to assess intradialytic hypoxia, and a potential biomarker of HD related stress and morbidity, helpful to recognize patients at increased risk of mortality.

Although many studies have been carried out in order to understand the implication of copper (Cu) in the pathogenesis of multiple sclerosis (MS), the exact role that this metal plays in the disease is not still clear. Because of the lack of information in this subject, the present study compared the serum and cerebrospinal (CSF) levels of copper in MS patients in respect to a control group, matched for age and sex, finding a significant increase of metal concentrations, in both biological fluids of MS subjects. To confirm the possible impairment of Cu metabolism, we analyzed ceruloplasmin (Cp) level and activity, seeing as this protein is an established peripheral marker in diseases associated with Cu imbalance. By comparing these two parameters between control and MS subjects, we found an increase of Cp levels, associated with a decrease in Cp activity, in the second group. By analysing these data, free copper levels were calculated, significantly increased in serum of MS subjects; the increase in free copper could be one of the predisposing factors responsible for the Cu altered levels in CSF of MS patients. At the same time, this alteration could be attributable to the inability to incorporate Cu by Cp, probably due to the high oxidative environment found in serum of MS patients. Overall, all these copper alterations may play a role in MS pathogenesis.