Hypovitaminosis D in patients undergoing kidney transplant: the importance of sunlight exposure

OBJECTIVES: Recent studies have shown a high prevalence of hypovitaminosis D, defined as a serum 25-hydroxyvitamin D level less than 30 ng/ml, in both healthy populations and patients with chronic kidney disease. Patients undergoing kidney transplant are at an increased risk of skin cancer and are advised to avoid sunlight exposure. Therefore, these patients might share two major risk factors for hypovitaminosis D: chronic kidney disease and low sunlight exposure. This paper describes the prevalence and clinical characteristics of hypovitaminosis D among patients undergoing kidney transplant. METHODS: We evaluated 25-hydroxyvitamin D serum levels in a representative sample of patients undergoing kidney transplant. We sought to determine the prevalence of hypovitaminosis D, compare these patients with a control group, and identify factors associated with hypovitaminosis D (e.g., sunlight exposure and dietary habits). RESULTS: Hypovitaminosis D was found in 79% of patients undergoing kidney transplant, and the major associated factor was low sunlight exposure. These patients had higher creatinine and intact parathyroid hormone serum levels, with 25-hydroxyvitamin D being inversely correlated with intact parathyroid hormone serum levels. Compared with the control group, patients undergoing kidney transplant presented a higher prevalence of 25-hydroxyvitamin D deficiency and lower serum calcium, phosphate and albumin but higher creatinine and intact parathyroid hormone levels. CONCLUSIONS: Our results confirmed the high prevalence of hypovitaminosis D in patients undergoing kidney transplant. Therapeutic strategies such as moderate sunlight exposure and vitamin D supplementation should be seriously considered for this population

Hypovitaminosis D in patients undergoing kidney transplant: the importance of sunlight exposure

OBJECTIVES: Recent studies have shown a high prevalence of hypovitaminosis D, defined as a serum 25-hydroxyvitamin D level less than 30 ng/ml, in both healthy populations and patients with chronic kidney disease. Patients undergoing kidney transplant are at an increased risk of skin cancer and are advised to avoid sunlight exposure. Therefore, these patients might share two major risk factors for hypovitaminosis D: chronic kidney disease and low sunlight exposure. This paper describes the prevalence and clinical characteristics of hypovitaminosis D among patients undergoing kidney transplant. METHODS: We evaluated 25-hydroxyvitamin D serum levels in a representative sample of patients undergoing kidney transplant. We sought to determine the prevalence of hypovitaminosis D, compare these patients with a control group, and identify factors associated with hypovitaminosis D (e.g., sunlight exposure and dietary habits). RESULTS: Hypovitaminosis D was found in 79% of patients undergoing kidney transplant, and the major associated factor was low sunlight exposure. These patients had higher creatinine and intact parathyroid hormone serum levels, with 25-hydroxyvitamin D being inversely correlated with intact parathyroid hormone serum levels. Compared with the control group, patients undergoing kidney transplant presented a higher prevalence of 25-hydroxyvitamin D deficiency and lower serum calcium, phosphate and albumin but higher creatinine and intact parathyroid hormone levels. CONCLUSIONS: Our results confirmed the high prevalence of hypovitaminosis D in patients undergoing kidney transplant. Therapeutic strategies such as moderate sunlight exposure and vitamin D supplementation should be seriously considered for this population

The Bone Histology Spectrum in Experimental Renal Failure: Adverse Effects of Phosphate and Parathyroid Hormone Disturbances

Bone disease is a common disorder of bone remodeling and mineral metabolism, which affects patients with chronic kidney disease. Minor changes in the serum level of a given mineral can trigger compensatory mechanisms, making it difficult to evaluate the role of mineral disturbances in isolation. The objective of this study was to determine the isolated effects that phosphate and parathyroid hormone (PTH) have on bone tissue in rats. Male Wistar rats were subjected to parathyroidectomy and 5/6 nephrectomy or were sham-operated. Rats were fed diets in which the phosphate content was low, normal, or high. Some rats received infusion of PTH at a physiological rate, some received infusion of PTH at a supraphysiological rate, and some received infusion of vehicle only. All nephrectomized rats developed moderate renal failure. High phosphate intake decreased bone volume, and this effect was more pronounced in animals with dietary phosphate overload that received PTH infusion at a physiological rate. Phosphate overload induced hyperphosphatemia, hypocalcemia, and changes in bone microarchitecture. PTH at a supraphysiological rate minimized the phosphate-induced osteopenia. These data indicate that the management of uremia requires proper control of dietary phosphate, together with PTH adjustment, in order to ensure adequate bone remodeling.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[01/01789-0]Genzym

The effect of vitamin D and zoledronic acid in bone marrow adiposity in kidney transplant patients: A post hoc analysis.

PURPOSE:Osteoblasts and adipocytes are derived from mesenchymal stem cells. An imbalance in the differentiation of these lineages could affect the preservation of bone integrity. Several studies have suggested the importance of this imbalance in the pathogenesis of osteoporosis after kidney transplant (KT), but the role of bone marrow adiposity in this process is not well known, and if the treatment with the anti-absorptive (zoledronic acid-ZA) drugs could attenuate bone loss. Thus, our objective was compare bone marrow adiposity, osteoblasts and osteocytes before and after KT, verify an association between bone remodeling process (Turnover, Volume, and Mineralization-TMV classification), the osteocyte sclerostin expression to evaluate if there is a role of Wnt pathway, as well as the effect of ZA on these cells. METHODS:We studied 29 new living-donor KT patients. One group received ZA at the time of KT plus cholecalciferol for twelve months, and the other group received only cholecalciferol. Bone biopsies were performed at baseline and after 12 months of treatment. Histomorphometric evaluation was performed in bone and bone marrow adipocytes. Sclerostin (Scl) expression in osteocytes was evaluated by immunohistochemistry. RESULTS:Some bone marrow adiposity parameters were increased before KT. After KT, some of them remained increased and they worsened with the use of ZA. In the baseline, lower bone Volume and Turnover, were associated with increased bone marrow adiposity parameters (some of them). After KT, both groups showed the same associations. Osteocyte Scl expression after KT decreased with the use of ZA. We observed also an inverse association between bone adiposity parameters and lower osteocyte sclerostin expression 12 months after KT. CONCLUSION:In conclusion, the present study suggests that KT fails to normalize bone marrow adiposity, and it even gets worse with the use of ZA. Moreover, bone marrow adiposity is inversely associated with bone Volume and Turnover, which seems to be accentuated by the antiresorptive therapy

Quality of life after surgery in secondary hyperparathyroidism, comparing subtotal parathyroidectomy with total parathyroidectomy with immediate parathyroid autograft:Prospective randomized trial

Background: No prospective randomized data exist about the impact of various strategies of parathyroidectomy in secondary hyperparathyroidism patients on quality of life and its possible relationship with metabolic status after the operation. Method: In a prospective randomized trial, the Short Form 36 Health Survey Questionnaire was applied to 69 patients undergoing parathyroidectomy through various approaches: subtotal parathyroidectomy (n = 23), total parathyroidectomy (PTx) with autotransplantation of 45 fragments (n = 25) and PTx with autotransplantation of 90 fragments (n = 21). The questionnaire was completed at three moments: (1) preoperatively, (2) 6 months after surgery, and (3) 12 months after surgery. Results: Quality of life improved significantly in the physical component summary score in all three groups. Subtotal parathyroidectomy scores changed from 30.6 preoperatively to 51.7 6 months after surgery and 53.7 12 months after surgery. Total arathyroidectomy with autotransplantation of 45 fragments scores changed from 33.8 preoperatively to 52.6 6 months after surgery and 55.2 12 months after surgery. Total parathyroidectomy with autotransplantation of 90 fragments scores changed from 31.8 preoperatively to 50.5 6 months after surgery and 55.2 12 months after surgery (all groups P <.0001). No significant difference was detected in the physical component summary score change among the three groups. The physical component summary score was negatively correlated to age, parathormone, and alkaline phosphatase preoperatively. Conclusion: Parathyroidectomy significantly improves quality of life in hemodialysis patients with secondary hyperparathyroidism, regardless of the type of operation. (C) 2018 Elsevier Inc. All rights reserved

Bone marrow adiposity parameters and N.Ob/BS in external controls and in the study population at baseline.

<p>Bone marrow adiposity parameters and N.Ob/BS in external controls and in the study population at baseline.</p

Representative microscopic features of osteocytes SOST expression by immunohistochemistry.

<p>In (A) negative control, (B) baseline of Vit D patient, (C) Vit D patient after KT, (D) baseline of ZA+Vit D patient, and (E) ZA+Vit D patient after KT (200x magnification).</p

Representative microscopic features of bone marrow.

<p>In (A) external control, (B) baseline of Vit D patient, (C) Vit D patient (D) baseline of ZA+ Vit D patient and (E) ZA+ Vit D patient. Toluidine blue staining (200x magnification).</p

Patients and external controls disposition.

<p>CKD: chronic kidney disease, KT: kidney transplant, ZA: zoledronic acid.</p