[Cholecalciferol supplementation improves secondary hyperparathyroidism control in renal transplant recipient].

Introduction: Vitamin D deficiency (25(OH)D <30 ng/mL) in renal transplant recipients (RTRs) is a frequent finding and represents an important component in the pathogenesis of secondary hyperparathyroidism (SHPT). Therefore, its more systematic supplementation is recommended. We herein report our experience on the impact of cholecalciferol supplementation on PTH and 25(OH)D levels in a group of RTRs with 25(OH)D <30 ng/mL and SHPT. Patients and Methods: For this purpose, 52 RTRs with SHPT were treated with cholecalciferol at the fixed dose of 25,000 IU p.o. weekly for 12 months. For the control group we selected 23 RTRs with SHPT and 25(OH)D levels <30 ng/mL. Every 6 weeks eGFR, sCa and sPO4 levels were evaluated; PTH, 25(OH)D, FECa e TmPO 4 were evaluated every 6 months. Results: At baseline, the two groups had similar clinical characteristics and biohumoral parameters. Parathormone was negatively correlated with 25(OH)D levels (r=-0.250; P <0.001) and TmPO4 values (r=-0.425; P<0.0001). At F-U there was a significant reduction in PTH levels in the supplemented group, from 131 ± 46 to 103 ± 42 pg/mL (P<0.001), while vitamin D levels, TmPO4 values, PO4 and sCa levels increased significantly, from 14.9 ± 6.5 to 37.9 ± 13.1 ng/mL (P<0.001), from 1.9 ± 0.7 to 2.6 ± 0.7 mg/dL (P<0.001), from 3.1 ± 0.5 to 3.5 ± 0.5 mg/dL (P<0.001), and from 9.3 ± 0.5 to 9.6 ± 0.4 (P<0.01), respectively. During the study there were no episodes of hypercalcaemia and/or hypercalciuria, while 25(OH)D levels always remained <100 ng/mL. In the control group, at F-U, PTH levels increased from 132 ± 49 to 169 ± 66 pg/ml (P <0.05), while 25(OH)D levels remained stable at <30 ng/mL. Conclusions: Vitamin D deficiency in RTRs is very frequent. Cholecalciferol supplementation is associated with a better control of SHPT and a correction of vitamin D deficiency in most patients, representing an effective, safe and inexpensive therapeutic approach to IPS.

[Association between low serum magnesium levels and the extent of abdominal aortic calcification in renal transplant recipients].

Introduction: In renal transplant recipients (RTRs) vascular calcifications has been associated with an increased risk of cardiovascular as well as all-cause mortality. Recent experimental and clinical studies showed that magnesium (Mg) deficiency may be related to the progression of vascular calcification. Aim of this study was to determine the hypothetical association between Mg and vascular calcifications in RTRs. Methods: Seventy-one RTRs underwent a lateral X-ray of the lumbar spine to assess the presence of calcification of the abdominal aorta. Abdominal aortic calcium (AAC) content was graded with a score ranging from 0 to 24 points. At the same time were evaluated: carotid artery intima-media thickness (IMT); left ventricular mass index (LVMi); sCa, sPO4, sMg, uMg, PTH, HDL, LDL, blood pressure (BP). Results: AAC was correlated with: age (r=0.601; P<0.001), dialysis vintage (r=0.314; P<0.01), sMg (r=-0.438; P<0.001), PTH (r=0.322; P<0.01), SBP (r=0.539; P<0.001), IMT (r=0.706; P<0.001), LVMi (r=0.326; P<0.01). Serum Mg was correlated with PTH (r= -0.304; P<0.01). IMT was correlated with LVMi and SBP (r=0.330, P<0.01; r=0.494, P <0.0001; respectively). Stepwise multiple regression analysis showed that the final model contained six predictor variables for AAC (IMT, sMg, age, SBP, proteinuria, and dialysis vintage; F5,64=31.7, P<0.001; Adjusted R2 =0.718). Patients in higher AAC thirtile (8-24) were older, with longer dialysis vintage, lower sMg, higher PTH, and higher IMT values. Conclusions: Our results suggest a hypothetical interrelationship between sMg and ACC, and IMT in RTRs.

[Correction of secondary hyperparathyroidism with paricalcitol in renal transplant improves left ventricular hypertrophy].

BACKGROUND: Left ventricular hypertrophy (LVH) is common in renal transplant recipients (RTRs), and persistent secondary hyperparathyroidism (SHPT) is considered to be one of the main causes of its pathogenesis. In this study we evaluated if the control of SHPT with paricalcitol is associated with a reduction of LVH in RTRs. METHODS: For this purpose we selected 24 RTRs with LVH and SHPT. Secondary hyperparathyroidism was defined as PTH levels 1.5 times higher than the high normal limits, while LVH was defined as a left ventricular mass index (LVMi) >95g/m2 in females, and >115g/m2 in males. Treatment with paricalcitol started at mean dose of 1µg/day and lasted 18 months. The dose of paricalcitol was reduced to 1µg on the other day when serum calcium was >10.5mg/dl and/or fractional excretion of calcium was >0.020%; administration was temporarily stopped when serum calcium was >11 mg/dl. RESULTS: At follow-up PTH levels decreased from 198 ± 155 to 105 ± 43pg/ml, and LVMi decreased from 134 ± 21 to 113 ± 29g/m2; the presence of LVH decreased from 100% at baseline to 54% at F-U. Serum calcium levels showed a modest and not significant increase. Renal function was stable in all patients. CONCLUSIONS: Secondary hyperparathyroidism seems to play an important role in the development and maintenance of LVH and its correction with paricalcitol has a favorable impact on its progression.