Paricalcitol for secondary hyperparathyroidism in renal transplantation. Trillini Matias,Cortinovis Monica,Ruggenenti Piero,Reyes Loaeza Jorge,Courville Karen,Ferrer-Siles Claudia,Prandini Silvia,Gaspari Flavio,Cannata Antonio,Villa Alessandro,Perna Annalisa,Gotti Eliana,Caruso Maria Rosa,Martinetti Davide,Remuzzi Giuseppe,Perico Norberto Journal of the American Society of Nephrology : JASN Secondary hyperparathyroidism contributes to post-transplant CKD mineral and bone disorder. Paricalcitol, a selective vitamin D receptor activator, decreased serum parathyroid hormone levels and proteinuria in patients with secondary hyperparathyroidism. This single-center, prospective, randomized, crossover, open-label study compared the effect of 6-month treatment with paricalcitol (1 μg/d for 3 months and then uptitrated to 2 µg/d if tolerated) or nonparicalcitol therapy on serum parathyroid hormone levels (primary outcome), mineral metabolism, and proteinuria in 43 consenting recipients of renal transplants with secondary hyperparathyroidism. Participants were randomized 1:1 according to a computer-generated sequence. Compared with baseline, median (interquartile range) serum parathyroid hormone levels significantly declined on paricalcitol from 115.6 (94.8-152.0) to 63.3 (52.0-79.7) pg/ml (P<0.001) but not on nonparicalcitol therapy. At 6 months, levels significantly differed between treatments (P<0.001 by analysis of covariance). Serum bone-specific alkaline phosphatase and osteocalcin decreased on paricalcitol therapy only and significantly differed between treatments at 6 months (P<0.001 for all comparisons). At 6 months, urinary deoxypyridinoline-to-creatinine ratio and 24-hour proteinuria level decreased only on paricalcitol (P<0.05). L3 and L4 vertebral mineral bone density, assessed by dual-energy x-ray absorption, significantly improved with paricalcitol at 6 months (P<0.05 for both densities). Paricalcitol was well tolerated. Overall, 6-month paricalcitol supplementation reduced parathyroid hormone levels and proteinuria, attenuated bone remodeling and mineral loss, and reduced eGFR in renal transplant recipients with secondary hyperparathyroidism. Long-term studies are needed to monitor directly measured GFR, ensure that the bone remodeling and mineral effects are sustained, and determine if the reduction in proteinuria improves renal and cardiovascular outcomes. 10.1681/ASN.2013111185

Diagnostic Accuracy of Biomarkers and Imaging for Bone Turnover in Renal Osteodystrophy. Salam Syazrah,Gallagher Orla,Gossiel Fatma,Paggiosi Margaret,Khwaja Arif,Eastell Richard Journal of the American Society of Nephrology : JASN Renal osteodystrophy is common in advanced CKD, but characterization of bone turnover status can only be achieved by histomorphometric analysis of bone biopsy specimens (gold standard test). We tested whether bone biomarkers and high-resolution peripheral computed tomography (HR-pQCT) parameters can predict bone turnover status determined by histomorphometry. We obtained fasting blood samples from 69 patients with CKD stages 4-5, including patients on dialysis, and 68 controls for biomarker analysis (intact parathyroid hormone [iPTH], procollagen type 1 N-terminal propeptide [PINP], bone alkaline phosphatase [bALP], collagen type 1 crosslinked C-telopeptide [CTX], and tartrate-resistant acid phosphatase 5b [TRAP5b]) and scanned the distal radius and tibia of participants by HR-pQCT. We used histomorphometry to evaluate bone biopsy specimens from 43 patients with CKD. Levels of all biomarkers tested were significantly higher in CKD samples than control samples. For discriminating low bone turnover, bALP, intact PINP, and TRAP5b had an areas under the receiver operating characteristic curve (AUCs) of 0.82, 0.79, and 0.80, respectively, each significantly better than the iPTH AUC of 0.61. Furthermore, radius HR-pQCT total volumetric bone mineral density and cortical bone volume had AUCs of 0.81 and 0.80, respectively. For discriminating high bone turnover, iPTH had an AUC of 0.76, similar to that of all other biomarkers tested. The biomarkers bALP, intact PINP, and TRAP5b and radius HR-pQCT parameters can discriminate low from nonlow bone turnover. Despite poor diagnostic accuracy for low bone turnover, iPTH can discriminate high bone turnover with accuracy similar to that of the other biomarkers, including CTX. 10.1681/ASN.2017050584