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Gabriella Oliveira Lima Laboratory of Pharmacology and Toxicology of Natural Products, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil

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Alex Luiz Menezes da Silva Laboratory of Pharmacology and Toxicology of Natural Products, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil

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Julianne Elba Cunha Azevedo Laboratory of Pharmacology and Toxicology of Natural Products, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil

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Chirlene Pinheiro Nascimento Laboratory of Pharmacology and Toxicology of Natural Products, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil

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Luana Rodrigues Vieira Laboratory of Pharmacology and Toxicology of Natural Products, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil

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Akira Otake Hamoy Laboratory of Pharmacology and Toxicology of Natural Products, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil

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Luan Oliveira Ferreira Laboratory of Experimental Neuropathology, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil

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Verônica Regina Lobato Oliveira Bahia Multidisciplinary Laboratory of Animal Morphology, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil

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Nilton Akio Muto Amazon Bioactive Compounds Valorization Center, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil

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Dielly Catrina Favacho Lopes Laboratory of Experimental Neuropathology, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil

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Moisés Hamoy Laboratory of Pharmacology and Toxicology of Natural Products, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil

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Low plasma levels of vitamin D causes bone mineral change that can precipitate osteopenia and osteoporosis and could aggravate autoimmune diseases, hypertension and diabetes. The demand for vitamin D supplementation becomes necessary; however, the consumption of vitamin D is not without risks, which its toxicity could have potentially serious consequences related to hypervitaminosis D, such as hypercalcemia and cerebral alterations. Thus, the present study describes the electroencephalographic changes caused by supraphysiological doses of vitamin D in the brain electrical dynamics and the electrocardiographic changes. After 4 days of treatment with vitamin D at a dose of 25,000 IU/kg, the serum calcium levels found were increased in comparison with the control group. The electrocorticogram analysis found a reduction in wave activity in the delta, theta, alpha and beta frequency bands. For ECG was observed changes with shortened QT follow-up, which could be related to serum calcium concentration. This study presented important evidence about the cerebral and cardiac alterations caused by high doses of vitamin D, indicating valuable parameters in the screening and decision-making process for diagnosing patients with symptoms suggestive of intoxication.

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Glenville Jones Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada

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Vitamin D has many physiological functions including upregulation of intestinal calcium and phosphate absorption, mobilization of bone resorption, renal reabsorption of calcium as well as actions on a variety of pleiotropic functions. It is believed that many of the hormonal effects of vitamin D involve a 1,25-dihydroxyvitamin D3-vitamin D receptor-mediated transcriptional mechanism involving binding to the cellular chromatin and regulating hundreds of genes in many tissues. This comprehensive historical review provides a unique perspective of the many steps of the discovery of vitamin D and its deficiency disease, rickets, stretching from 1650 until the present. The overview is divided into four distinct historical phases which cover the major developments in the field and in the process highlighting the: (a) first recognition of rickets or vitamin D deficiency; (b) discovery of the nutritional factor, vitamin D and its chemical structure; (c) elucidation of vitamin D metabolites including the hormonal form, 1,25-dihydroxyvitamin D3; (d) delineation of the vitamin D cellular machinery, functions and vitamin D-related diseases which focused on understanding the mechanism of action of vitamin D in its many target cells.

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Shu-Meng Hu Department of Nephrology, West China Hospital, Sichuan University, Chengdu, Sichuan, China

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Yang-Juan Bai Department of Laboratory Medicine/Research Centre of Clinical Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China

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Ya-Mei Li Department of Laboratory Medicine/Research Centre of Clinical Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China

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Ye Tao Department of Nephrology, West China Hospital, Sichuan University, Chengdu, Sichuan, China

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Xian-Ding Wang Department of Urology/Institute of Urology, West China Hospital, Sichuan University, Chengdu, Sichuan, China

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Tao Lin Department of Urology/Institute of Urology, West China Hospital, Sichuan University, Chengdu, Sichuan, China

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Lan-Lan Wang Department of Laboratory Medicine/Research Centre of Clinical Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China

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Yun-Ying Shi Department of Nephrology, West China Hospital, Sichuan University, Chengdu, Sichuan, China

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Introduction

Tertiary hyperparathyroidism (THPT) and vitamin D deficiency are commonly seen in kidney transplant recipients, which may result in persistently elevated fibroblast growth factor 23 (FGF23) level after transplantation and decreased graft survival. The aim of this study is to evaluate the effect of vitamin D supplementation on THPT, FGF23-alpha Klotho (KLA) axis and cardiovascular complications after transplantation.

Materials and methods

Two hundred nine kidney transplant recipients were included and further divided into treated and untreated groups depending on whether they received vitamin D supplementation. We tracked the state of THPT, bone metabolism and FGF23–KLA axis within 12 months posttransplant and explored the predictors and risk factors for intact FGF23 levels, KLA levels, THPT and cardiovascular complications in recipients.

Results

Vitamin D supplementation significantly improved FGF23 resistance, THPT and high bone turnover status, preserved better graft function and prevented coronary calcification in the treated group compared to the untreated group at month 12. The absence of vitamin D supplementation was an independent risk factor for THPT and a predictor for intact FGF23 and KLA levels at month 12. Age and vitamin D deficiency were independent risk factors for coronary calcification in recipients at month 12.

Conclusion

Vitamin D supplementation effectively improved THPT, FGF23 resistance and bone metabolism, preserved graft function and prevented coronary calcification after transplantation.

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Julie Wulf Christensen Department of Nuclear Medicine, Herlev and Gentofte Hospital, Herlev, Denmark

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Karin Folmer Thøgersen Department of Nuclear Medicine, Herlev and Gentofte Hospital, Herlev, Denmark

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Lars Thorbjørn Jensen Department of Nuclear Medicine, Herlev and Gentofte Hospital, Herlev, Denmark

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Martin Krakauer Department of Nuclear Medicine, Herlev and Gentofte Hospital, Herlev, Denmark
Department of Clinical Physiology and Nuclear Medicine, Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark

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Bent Kristensen Department of Nuclear Medicine, Herlev and Gentofte Hospital, Herlev, Denmark

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Finn Noe Bennedbæk Division of Endocrinology, Department of Medicine, Herlev and Gentofte Hospital, Herlev, Denmark

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Bo Zerahn Department of Nuclear Medicine, Herlev and Gentofte Hospital, Herlev, Denmark

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Objective

The extent of symptoms due to primary hyperparathyroidism (PHPT) depends on the population being studied. PHPT is mainly discovered incidentally through routine laboratory findings. Less is known about patient-experienced improvement following successful parathyroidectomy. The aim of our study was to assess the changes in the quality of life (QoL) after successful surgery using an SF-36 questionnaire.

Design

This is a prospective cohort study based on questionnaires.

Methods

Forty consecutive patients diagnosed with PHPT were prospectively administered an SF-36 questionnaire before and 6 months after successful parathyroidectomy. A subgroup of 18 patients answered the questionnaire at 1 and 3 months after surgery. Successful surgery was based on biochemistry and pathology reports as confirmed by an endocrinologist. Results of each SF-36 subcategory were compared to the results at baseline in order to detect changes in patient-reported QoL after successful surgery.

Results

There were significant improvements in six of eight SF-36 subcategories: vitality (P = 0.0001), physical functioning (P = 0.04), general health perception (P = 0.004), physical role functioning (P = 0.04), social role functioning (P = 0.004), and mental health perception (P = 0.0001). Changes appeared within a month after surgery with no further significant changes at later time points.

Conclusions

Parathyroidectomy significantly improves QoL as measured by a decrease in SF-36 scores as early as 1 month after successful parathyroidectomy. The SF-36 QoL questionnaire is suitable for monitoring changes in patient well-being after successful parathyroidectomy.

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Qian Wang Department of Thyroid and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China

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Jiacheng Wang Department of Thyroid and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China

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Yunhui Xin Department of Thyroid and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China

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Ziyang He Department of Thyroid and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China

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Xiang Zhou Department of Pathology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China

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Xing Liu Department of Thyroid and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China

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Teng Zhao Department of Thyroid and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China

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Lihan He Department of Thyroid and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China

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Hong Shen Department of Thyroid and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China

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Mulan Jin Department of Pathology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China

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Bojun Wei Department of Thyroid and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China

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Background

Parathyroid carcinoma (PC), often misdiagnosed as a parathyroid adenoma (PA), is prone to local relapse due to the initial surgery being restricted to parathyroid lesions instead of en bloc resection of parathyroid lesions with negative incision margins. However, it is very challenging to distinguish PC from PA preoperatively; hence, this study investigated an effective biomarker for increasing accuracy in PC diagnosis.

Method

First, the differentially expressed circular RNAs between three PC tissues and three PA tissues were screened by high-throughput circular RNA sequencing, and the expression of hsa_circ_0005729 was verified by qRT-PCR in 14 patients with PC and 40 patients with PA. Secondly, the receiver operating characteristic curve and the area under the curve (AUC) were used to analyze the diagnostic efficiency of hsa_circ_0005729 in PC by combining with laboratory data. Thirdly, RNF138mRNA, the corresponding linear transcript of hsa_circ_0005729, was measured, and the relationship between hsa_circ_0005729 and RNF138 mRNA was analyzed in patients with PA and patients with PC.

Results

Hsa_circ_0005729 expression was significantly higher in patients with PC than in patients with PA. Serum calcium (P  = 0.045), alkaline phosphatase (ALP) (P  = 0.048), and creatinine levels (P  = 0.036) were significantly higher in patients with PC than in patients with PA. The AUC increased to 0.86 when hsa_circ_0005729 combined with serum calcium, creatinine, and ALP. In addition, hsa_circ_0005729 was positively correlated with RNF138 mRNA in patients with PA but not in patients with PC.

Conclusion

The novel circular RNA hsa_circ_0005729 was found to have a higher expression in patients with PC, indicating its usefulness for distinguishing PC from PA.

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Marília D’Elboux Guimarães Brescia Endocrine Genetics Unit (LIM-25), Endocrinology Division, University of São Paulo School of Medicine (FMUSP), Faculdade de Medicina da Universidade de São Paulo (FMUSP), Hospital das Clinicas (HCFMUSP), São Paulo, São Paulo, Brazil
Parathyroid Unit – LIM-28, Laboratório de Cirurgia de Cabeça e Pescoço, Division of Head and Neck Surgery, Department of Surgery, Hospital das Clinicas (HCFMUSP), University of São Paulo School of Medicine (FMUSP), Faculdade de Medicina, Universidade de São Paulo, São Paulo, São Paulo, Brazil

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Karine Candido Rodrigues Endocrine Genetics Unit (LIM-25), Endocrinology Division, University of São Paulo School of Medicine (FMUSP), Faculdade de Medicina da Universidade de São Paulo (FMUSP), Hospital das Clinicas (HCFMUSP), São Paulo, São Paulo, Brazil
Endocrine Oncology Division, Institute of Cancer of the State of São Paulo (ICESP), University of São Paulo School of Medicine (FMUSP), Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, São Paulo, Brazil

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André Fernandes d’Alessandro Parathyroid Unit – LIM-28, Laboratório de Cirurgia de Cabeça e Pescoço, Division of Head and Neck Surgery, Department of Surgery, Hospital das Clinicas (HCFMUSP), University of São Paulo School of Medicine (FMUSP), Faculdade de Medicina, Universidade de São Paulo, São Paulo, São Paulo, Brazil

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Wellington Alves Filho Department of Surgery, Walter Cantidio University Hospital, Federal University of Ceara School of Medicine (FAMED-UFC), Fortaleza, Brazil

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Willemijn Y van der Plas Department of Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands

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Schelto Kruijff Department of Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands

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Sergio Samir Arap Parathyroid Unit – LIM-28, Laboratório de Cirurgia de Cabeça e Pescoço, Division of Head and Neck Surgery, Department of Surgery, Hospital das Clinicas (HCFMUSP), University of São Paulo School of Medicine (FMUSP), Faculdade de Medicina, Universidade de São Paulo, São Paulo, São Paulo, Brazil

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Sergio Pereira de Almeida Toledo Endocrine Genetics Unit (LIM-25), Endocrinology Division, University of São Paulo School of Medicine (FMUSP), Faculdade de Medicina da Universidade de São Paulo (FMUSP), Hospital das Clinicas (HCFMUSP), São Paulo, São Paulo, Brazil

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Fábio Luiz de Menezes Montenegro Parathyroid Unit – LIM-28, Laboratório de Cirurgia de Cabeça e Pescoço, Division of Head and Neck Surgery, Department of Surgery, Hospital das Clinicas (HCFMUSP), University of São Paulo School of Medicine (FMUSP), Faculdade de Medicina, Universidade de São Paulo, São Paulo, São Paulo, Brazil

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Delmar Muniz Lourenço Jr Endocrine Genetics Unit (LIM-25), Endocrinology Division, University of São Paulo School of Medicine (FMUSP), Faculdade de Medicina da Universidade de São Paulo (FMUSP), Hospital das Clinicas (HCFMUSP), São Paulo, São Paulo, Brazil
Endocrine Oncology Division, Institute of Cancer of the State of São Paulo (ICESP), University of São Paulo School of Medicine (FMUSP), Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, São Paulo, Brazil

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Background

Potential influences of parathyroidectomy (PTx) on the quality of life (QoL) in multiple endocrine neoplasia type 1-related primary hyperparathyroidism (HPT/MEN1) are unknown.

Method

Short Form 36 Health Survey Questionnaire was prospectively applied to 30 HPT/MEN1 patients submitted to PTx (20, subtotal; 10, total with autograft) before, 6 and 12 months after surgery. Parameters that were analyzed included QoL, age, HPT-related symptoms, general pain, comorbidities, biochemical/hormonal response, PTx type and parathyroid volume.

Results

Asymptomatic patients were younger (30 vs 38 years; P = 0.04) and presented higher QoL scores than symptomatic ones: Physical Component Summary score (PCS) 92.5 vs 61.2, P = 0.0051; Mental Component Summary score (MCS) 82.0 vs 56.0, P = 0.04. In both groups, QoL remained stable 1 year after PTx, independently of the number of comorbidities. Preoperative general pain was negatively correlated with PCS (r = −0.60, P = 0.0004) and MCS (r = −0.57, P = 0.0009). Also, moderate/intense pain was progressively (6/12 months) more frequent in cases developing hypoparathyroidism. The PTx type and hypoparathyroidism did not affect the QoL at 12 months although remnant parathyroid tissue volume did have a positive correlation (P = 0.0490; r = 0.3625) to PCS 12 months after surgery. Patients with one to two comorbidities had as pre-PTx PCS (P = 0.0015) as 12 months and post-PTx PCS (P = 0.0031) and MCS (P = 0.0365) better than patients with three to four comorbidities.

Conclusion

A variable QoL profile was underscored in HPT/MEN1 reflecting multiple factors associated with this complex disorder as comorbidities, advanced age at PTx and presence of preoperative symptoms or of general pain perception. Our data encourage the early indication of PTx in HPT/MEN1 by providing known metabolic benefits to target organs and avoiding potential negative impact on QoL.

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Magdaléna Fořtová Department of Medical Chemistry and Clinical Biochemistry, Charles University, Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic

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Lenka Hanousková Department of Medical Chemistry and Clinical Biochemistry, Charles University, Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic

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Martin Valkus Department of Medical Chemistry and Clinical Biochemistry, Charles University, Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic

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Jana Čepová Department of Medical Chemistry and Clinical Biochemistry, Charles University, Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic

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Richard Průša Department of Medical Chemistry and Clinical Biochemistry, Charles University, Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic

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Karel Kotaška Department of Medical Chemistry and Clinical Biochemistry, Charles University, Second Faculty of Medicine and University Hospital Motol, Prague, Czech Republic

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Background

Fibroblast growth factor 23 (FGF23) is a key regulator of urine phosphate excretion. The aim of the study was to investigate the perioperative (intraoperative and postoperative) changes of plasma intact and C-terminal FGF23 (iFGF23, cFGF23) concentrations in patients with primary hyperparathyroidism (pHPT) submitted to surgery.

Materials and methods

The study involved 38 adult patients with pHPT caused by adenoma. Parathyroid hormone (PTH) levels were investigated intraoperatively (just before the incision and 10 min after adenoma excision). cFGF23, iFGF23, phosphate, estimated glomerular filtration rate (eGFR), and procollagen type 1 N-terminal propetide (P1NP) were measured intraoperatively and postoperatively (next day after the surgery).

Results

PTH levels decreased intraoperatively (13.10 pmol/L vs 4.17 pmol/L, P< 0.0001). FGF23 levels measured intraoperatively were at the upper level of reference interval. cFGF23 decreased postoperatively compared with the values measured just before the incision (cFGF23: 89.17 RU/mL vs 22.23 RU/mL, P< 0.0001). iFGF23 decreased as well, but the postoperative values were low. Postoperative inorganic phosphate values increased (1.03 mmol/L vs 0.8 mmol/L, P= 0.0025). We proved significant negative correlation of perioperative FGF23 with inorganic phosphate (cFGF23: Spearman’s r = −0.253, P= 0.0065; iFGF23: Spearman’s r = −0.245, P= 0.0085). We also found that FGF23 values just before incision correlated with eGFR (cystatin C) (cFGF23: Spearman’s r = −0.499, P= 0.0014; iFGF23: Spearman’s r = −0.413, P= 0.01).

Conclusion

Intraoperative iFGF23 and cFGF23 did not change despite PTH decreased significantly. cFGF23 and iFGF23 significantly decreased 1 day after parathyroidectomy and are associated with increase of inorganic phosphate in pHPT patients. cFGF23 and iFGF23 just before incision correlated with eGFR (cystatin C). Similar results found in both iFGF23 and cFGF23 suggest that each could substitute the other.

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Niek F Dirks Atalmedial Diagnostics Centre, Spaarne Gasthuis, Haarlem, The Netherlands
Department of Clinical Chemistry, Hematology and Immunology, Noordwest Ziekenhuis, Alkmaar, The Netherlands

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Etienne Cavalier Department of Clinical Chemistry, University of Liège, CHU de Liège, Liège, Belgium

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Annemieke C Heijboer Amsterdam UMC location Vrije Universiteit Amsterdam, Department of Clinical Chemistry, Endocrine Laboratory, Boelelaan, Amsterdam, The Netherlands
Amsterdam Gastroenterology, Endocrinology & Metabolism, Amsterdam, The Netherlands
Amsterdam UMC location University of Amsterdam, Department of Clinical Chemistry, Endocrine Laboratory, Amsterdam, The Netherlands
Amsterdam Reproduction & Development Research Institute, Amsterdam, The Netherlands

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The measurement of vitamin D metabolites aids in assessing vitamin D status and in diagnosing disorders of calcium homeostasis. Most laboratories measure total 25-hydroxyvitamin D (25(OH)D), while others have taken the extra effort to measure 25(OH)D2 and 25(OH)D3 separately and additional metabolites such as 1,25-dihydroxyvitamin D and 24,25-dihydroxyvitamin D. The aim of this review is to provide an updated overview of the main markers of vitamin D metabolism, define the intended measurands, and discuss the advantages and disadvantages of the two most widely used assays, automated assays and liquid chromatography–tandem mass spectrometry (LC-MS/MS). Whether using the easy and fast automated assays or the more complex LC-MS/MS, one should know the pitfalls of the used technique in order to interpret the measurements. In conclusion, automated assays are unable to accurately measure 25(OH)D in all patient groups, including persons using D2. In these cases, an LC-MS/MS method, when appropriately developed and standardized, produces a more reliable measurement.

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Jane Fletcher Nutrition Nurses, University Hospitals Birmingham NHS Trust, Queen Elizabeth Hospital Birmingham, Mindelsohn Way, Edgbaston, Birmingham, UK
School of Nursing, Institute of Clinical Sciences, University of Birmingham, Edgbaston, Birmingham, UK

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Emma L Bishop Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, UK

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Stephanie R Harrison Leeds Institute of Rheumatic and Musculoskeletal Medicine, Chapel Allerton Hospital, Leeds, UK

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Amelia Swift School of Nursing, Institute of Clinical Sciences, University of Birmingham, Edgbaston, Birmingham, UK

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Sheldon C Cooper Gastroenterology Department, University Hospitals Birmingham NHS Trust, Queen Elizabeth Hospital Birmingham, Mindelsohn Way, Edgbaston, Birmingham, UK

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Sarah K Dimeloe Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, UK

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Karim Raza Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK

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Martin Hewison Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK

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Vitamin D has well-documented effects on calcium homeostasis and bone metabolism but recent studies suggest a much broader role for this secosteroid in human health. Key components of the vitamin D system, notably the vitamin D receptor (VDR) and the vitamin D-activating enzyme (1α-hydroxylase), are present in a wide array of tissues, notably macrophages, dendritic cells and T lymphocytes (T cells) from the immune system. Thus, serum 25-hydroxyvitamin D (25D) can be converted to hormonal 1,25-dihydroxyvitamin D (1,25D) within immune cells, and then interact with VDR and promote transcriptional and epigenomic responses in the same or neighbouring cells. These intracrine and paracrine effects of 1,25D have been shown to drive antibacterial or antiviral innate responses, as well as to attenuate inflammatory T cell adaptive immunity. Beyond these mechanistic observations, association studies have reported the correlation between low serum 25D levels and the risk and severity of human immune disorders including autoimmune diseases such as inflammatory bowel disease, multiple sclerosis, type 1 diabetes and rheumatoid arthritis. The proposed explanation for this is that decreased availability of 25D compromises immune cell synthesis of 1,25D leading to impaired innate immunity and over-exuberant inflammatory adaptive immunity. The aim of the current review is to explore the mechanistic basis for immunomodulatory effects of 25D and 1,25D in greater detail with specific emphasis on how vitamin D-deficiency (low serum levels of 25D) may lead to dysregulation of macrophage, dendritic cell and T cell function and increase the risk of inflammatory autoimmune disease.

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Johanna Öberg Tromso Endocrine Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, Tromso, Norway

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Rolf Jorde Tromso Endocrine Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, Tromso, Norway

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Yngve Figenschau Tromso Endocrine Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, Tromso, Norway
Diagnostic Clinic, University Hospital of North Norway, Tromso, Norway

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Per Medbøe Thorsby Hormone Laboratory, Department of Medical Biochemistry and Biochemical Endocrinology and Metabolism Research Group, Oslo University Hospital, Aker, Oslo, Norway

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Sandra Rinne Dahl Hormone Laboratory, Department of Medical Biochemistry and Biochemical Endocrinology and Metabolism Research Group, Oslo University Hospital, Aker, Oslo, Norway

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Anne Winther Division of Neurosciences, Orthopedics and Rehabilitation Services, University Hospital of North Norway, Tromso, Norway

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Guri Grimnes Tromso Endocrine Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, Tromso, Norway
Division of Internal Medicine, University Hospital of North Norway, Tromso, Norway

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Objective

Combined hormonal contraceptive (CHC) use has been associated with higher total 25-hydroxyvitamin D (25(OH)D) levels. Here, we investigate the relation between CHC use and vitamin D metabolism to elucidate its clinical interpretation.

Methods

The cross-sectional Fit Futures 1 included 1038 adolescents. Here, a subgroup of 182 girls with available 25(OH)D, 1,25-dihydroxyvitamin D (1,25(OH)2D), 24,25-dihydroxyvitamin D (24,25(OH)2D), vitamin D-binding protein (DBP) and measured free 25(OH)D levels, in addition to parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23), was investigated. Vitamin D metabolites were compared between girls using (CHC+) and not using CHC (CHC−). Further, the predictability of CHC on 25(OH)D levels was assessed in a multiple regression model including lifestyle factors. The ratios 1,25(OH)2D/25(OH)D and 24,25(OH)2D/25(OH)D (vitamin D metabolite ratio (VMR)) in relation to 25(OH)D were presented in scatterplots.

Results

CHC+ (n  = 64; 35% of the girls) had higher 25(OH)D levels (mean ± s.d., 60.3 ± 22.2) nmol/L) than CHC- (n  = 118; 41.8 ± 19.3 nmol/L), P -values <0.01. The differences in 25(OH)D levels between CHC+ and CHC− were attenuated but remained significant after the adjustment of lifestyle factors. CHC+ also had higher levels of 1,25(OH)2D, 24,25(OH)2D, DBP and calcium than CHC−, whereas 1,25(OH)2D/25(OH)D, PTH, FGF23 and albumin were significantly lower. Free 25(OH)D and VMR did not statistically differ, and both ratios appeared similar in relation to 25(OH)D, irrespective of CHC status.

Conclusion

This confirms a clinical impact of CHC on vitamin D levels in adolescents. Our observations are likely due to an increased DBP-concentration, whereas the free 25(OH)D appears unaltered.

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