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Berggren SS, Dahlgren J, Andersson O, Bergman S, Roswall J. Reference limits for osteocalcin in infancy and early childhood: A longitudinal birth cohort study. Clin Endocrinol (Oxf) 2024; 100:399-407. [PMID: 38385947 DOI: 10.1111/cen.15036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/26/2024] [Accepted: 02/08/2024] [Indexed: 02/23/2024]
Abstract
OBJECTIVE The longitudinal variations in serum levels of the hormone osteocalcin is largely unknown during infancy and early childhood. Our aim was to establish reference limits for total serum osteocalcin during specific time points from birth until 5 years of age and present those in the context of sex, breastfeeding practices and gestational age (GA). DESIGN Blood samples from 551 Swedish children were analysed at birth, 4, 12, 36 and 60 months of age. Total serum osteocalcin was measured using the IDS-iSYS N-MID Osteocalcin assay technique. Information about the mother, birth, anthropometrics and a food diary were collected. RESULTS Sex-specific and age-specific reference limits were established for the five time points. The median osteocalcin levels over time were 40.8, 90.0, 67.8, 62.2 and 80.9 μg/L for boys and 38.1, 95.5, 78.3, 73.9 and 92.6 μg/L for girls. Lower GA was associated to higher osteocalcin at birth, and ongoing breastfeeding was associated to higher osteocalcin levels. CONCLUSION Osteocalcin followed a wavelike pattern with low levels in the umbilical cord and a postnatal peak during the first year which then declined and rose again by the age of five. Knowledge of this wavelike pattern and association to factors as sex, breastfeeding and GA may help clinicians to interpret individual osteocalcin levels and guide in future research.
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Affiliation(s)
- Sara S Berggren
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Health Center Hyltebruk, Hyltebruk, Halland, Sweden
| | - Jovanna Dahlgren
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Pediatrics, Västra Götalandregion, Queen Silvia Children's Hospital, Lund, Sweden
| | - Ola Andersson
- Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Stefan Bergman
- Department of Public Health and Community Medicine, Primary Health Care Unit, University of Gothenburg, Gothenburg, Sweden
- Spenshult Research and Development Centre, Halmstad, Sweden
| | - Josefine Roswall
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Pediatrics, Halland Hospital Halmstad, Halmstad, Sweden
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Kiely ME, Wagner CL, Roth DE. Vitamin D in pregnancy: Where we are and where we should go. J Steroid Biochem Mol Biol 2020; 201:105669. [PMID: 32302652 DOI: 10.1016/j.jsbmb.2020.105669] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 03/18/2020] [Accepted: 04/02/2020] [Indexed: 01/06/2023]
Abstract
Vitamin D deficiency has been widely reported among pregnant women and infants around the world. Women with low sun exposure, high BMI, low vitamin D intakes and socioeconomic disadvantage with poor quality diets are at greatest risk of vitamin D deficiency, leading to very low serum concentrations of 25-hydroxyvitamin D (25(OH)D) in their offspring and an increased risk of nutritional rickets. Many observational studies, supported by compelling in vitro and in vivo data, have generated evidence suggesting that low vitamin D status in pregnancy may also contribute to the risk of adverse perinatal outcomes including hypertensive disorders (e.g., preeclampsia), fetal growth restriction, and preterm birth. However, the few large randomized controlled trials (RCTs) conducted to date have generated conflicting evidence for a role of vitamin D supplementation in improving perinatal outcomes. Vitamin D supplementation policies during pregnancy and implementation of policies vary within and between jurisdictions. Regulatory authorities have cited insufficient evidence to establish pregnancy-specific targets for serum 25(OH)D concentrations or prenatal vitamin D intake that effectively reduce the risks of adverse perinatal and infant outcomes. This paper arises from a Debate on Vitamin D Requirements during Pregnancy, held at the 22nd Vitamin D Workshop, 2019. From varied perspectives, our objectives were to evaluate the evidence for: vitamin D metabolism in pregnancy and the prevalence of gestational vitamin D deficiency worldwide; the translation of laboratory research findings to clinical studies on the role of vitamin D in perinatal health; the challenges of designing and conducting clinical trials to establish prenatal vitamin D requirements; and results to date of major large RCTs of prenatal vitamin D supplementation. Lastly, we explored potential next steps towards generating robust clinical data in this field to address both public health protection and patient care.
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Affiliation(s)
- M E Kiely
- Cork Centre for Vitamin D and Nutrition Research, School of Food and Nutritional Sciences, University College Cork, Ireland; INFANT Research Centre, University College Cork, Ireland.
| | - C L Wagner
- Division of Neonatology, Medical University of South Carolina, Charleston, SC 29425, United States
| | - D E Roth
- Department of Pediatrics, The Hospital for Sick Children, Toronto, ON, Canada
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3
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Kovacs CS. Bone development and mineral homeostasis in the fetus and neonate: roles of the calciotropic and phosphotropic hormones. Physiol Rev 2014; 94:1143-218. [PMID: 25287862 DOI: 10.1152/physrev.00014.2014] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mineral and bone metabolism are regulated differently in utero compared with the adult. The fetal kidneys, intestines, and skeleton are not dominant sources of mineral supply for the fetus. Instead, the placenta meets the fetal need for mineral by actively transporting calcium, phosphorus, and magnesium from the maternal circulation. These minerals are maintained in the fetal circulation at higher concentrations than in the mother and normal adult, and such high levels appear necessary for the developing skeleton to accrete a normal amount of mineral by term. Parathyroid hormone (PTH) and calcitriol circulate at low concentrations in the fetal circulation. Fetal bone development and the regulation of serum minerals are critically dependent on PTH and PTH-related protein, but not vitamin D/calcitriol, fibroblast growth factor-23, calcitonin, or the sex steroids. After birth, the serum calcium falls and phosphorus rises before gradually reaching adult values over the subsequent 24-48 h. The intestines are the main source of mineral for the neonate, while the kidneys reabsorb mineral, and bone turnover contributes mineral to the circulation. This switch in the regulation of mineral homeostasis is triggered by loss of the placenta and a postnatal fall in serum calcium, and is followed in sequence by a rise in PTH and then an increase in calcitriol. Intestinal calcium absorption is initially a passive process facilitated by lactose, but later becomes active and calcitriol-dependent. However, calcitriol's role can be bypassed by increasing the calcium content of the diet, or by parenteral administration of calcium.
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Affiliation(s)
- Christopher S Kovacs
- Faculty of Medicine-Endocrinology, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
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4
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Kovacs CS. The Role of PTHrP in Regulating Mineral Metabolism During Pregnancy, Lactation, and Fetal/Neonatal Development. Clin Rev Bone Miner Metab 2014. [DOI: 10.1007/s12018-014-9157-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Thandrayen K, Pettifor JM. Maternal vitamin D status: implications for the development of infantile nutritional rickets. Rheum Dis Clin North Am 2012; 38:61-79. [PMID: 22525843 DOI: 10.1016/j.rdc.2012.03.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The mother is the major source of circulating 25-OHD concentrations in the young infant. Thus maternal vitamin D status is an important factor in determining the vitamin D status of the infant and their risk of developing vitamin D deficiency and infantile nutritional rickets. As a result, breastfed infants of mothers with vitamin D deficiency who are unsupplemented and who receive little sunlight exposure are at high risk of developing vitamin D deficiency or rickets. Despite food fortification policies in many countries and recommendations for vitamin D supplementation of at-risk groups, vitamin D deficiency and infantile rickets remain major public health challenges in many developed and developing countries. There is evidence that the current supplementation recommendations, particularly for pregnant and lactating women, are inadequate to ensure vitamin D sufficiency in these groups. A widespread and concerted effort is needed to ensure daily supplementation of breastfed and other infants at high risk with vitamin D 400 IU from birth and pregnant women in high risk communities with at least 600 IU; awareness needs to be developed among the public and medical practitioners of the urgent need to improve the vitamin D status of pregnant and lactating mothers and their infants. Further studies are required to determine the optimal doses of vitamin D supplementation in pregnancy and during lactation, and for normalizing vitamin D stores in infancy to reduce the prevalence of infantile nutritional rickets. Operational research studies also need to be conducted to understand the best methods of implementing supplementation programs and the factors that are likely to impede their success.
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Affiliation(s)
- Kebashni Thandrayen
- MRC Developmental Pathways for Health Research Unit, Deptartment of Pediatrics, Chris Hani Baragwanath Hospital, PO Bertsham, Johannesburg 2013, South Africa.
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Extrarenal expression of the 25-hydroxyvitamin D-1-hydroxylase. Arch Biochem Biophys 2012; 523:95-102. [PMID: 22446158 DOI: 10.1016/j.abb.2012.02.016] [Citation(s) in RCA: 172] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 02/21/2012] [Accepted: 02/23/2012] [Indexed: 12/19/2022]
Abstract
Like the vitamin D receptor (VDR), the CYP27B1-hydroxylase is expressed widely in human tissues. This expression profile establishes the potential for interaction of the VDR with the product of the CYP27B1, 1,25-dihydroxyvitamin D (1,25-(OH)(2)D), in either an intracrine or paracrine mode. This expansive expression profile also suggests that the local production and action of 1,25-(OH)(2)D to regulate VDR-directed gene expression may be similarly wide-ranging and distinct from what occurs in the kidney; the proximal renal tubular epithelial cell is the richest source of the CYP27B1 and the site for production of 1,25-(OH)(2)D destined to function as a hormone. Existence of the CYP27B1 at extrarenal sites has been widely documented, although the functional impact of the enzyme in these tissues has yet to be fully demonstrated. Two notable exceptions are the disease-activated macrophage (e.g., in sarcoidosis or tuberculosis) and the placenta. These two tissues are capable of generating enough 1,25-(OH)(2)D so as to be detectable in the general circulation. As such, this review will focus on CYP27B1 expression only at these two sites, theorizing that 1,25-(OH)(2)D production at these sites is for the purpose of local immunoregulatory function, not for controlling calcium balance in the host or the fetus.
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7
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Liu NQ, Hewison M. Vitamin D, the placenta and pregnancy. Arch Biochem Biophys 2011; 523:37-47. [PMID: 22155151 DOI: 10.1016/j.abb.2011.11.018] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 11/18/2011] [Accepted: 11/21/2011] [Indexed: 12/19/2022]
Abstract
Impaired vitamin D status is common to many populations around the world. However, data suggest that this is a particular problem for specific groups such as pregnant women. This has raised important questions concerning the physiological and clinical impact of low vitamin D levels during pregnancy, with implications for classical skeletal functions of vitamin D, as well as its diverse non-classical actions. The current review will discuss this with specific emphasis on the classical calciotropic effects of vitamin D as well as the less well established immunological functions of vitamin D that may influence pregnancy outcome. The review also describes the pathways that are required for metabolism and function of vitamin D, and the various clinical complications that have been linked to impaired vitamin D status during pregnancy.
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Affiliation(s)
- N Q Liu
- Department of Orthopaedic Surgery and Molecular Biology Institute, David Geffen School of Medicine at UCLA, 615 Charles E. Young Drive South, Los Angeles, CA 90095, USA
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8
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Abstract
During embryonic and fetal development much of the skeleton initiates as a cartilaginous scaffold, which is progressively resorbed and replaced by bone. Endochondral bone formation continues until the growth plates fuse during puberty. At all life stages adequate delivery of mineral is required for the skeleton to achieve and maintain appropriate mineral content and strength. During fetal development the placenta actively transports calcium, phosphorus, and magnesium. Postnatally passive and then active absorption from the intestines becomes the main supply of minerals to the skeleton. Animal and human data indicate that fetal bone development requires parathyroid hormone (PTH) and PTH-related protein but not vitamin D/calcitriol, calcitonin, or (possibly) sex steroids. During the postnatal period, when intestinal calcium absorption becomes an active process, skeletal development begins to depend upon vitamin D/calcitriol but this requirement can be bypassed by increasing the calcium content of the diet or by administering intermittent calcium infusions.
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Affiliation(s)
- Christopher S Kovacs
- Medicine (Endocrinology and Metabolism), Obstetrics & Gynecology, and BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, Health Sciences Centre, 300 Prince Philip Drive, St. John's, Newfoundland, A1B 3V6, Canada.
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9
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Abstract
Pregnancy and lactation cause a substantial increase in demand for calcium that is met by different maternal adaptations within each period. Intestinal calcium absorption more than doubles during pregnancy, whereas the maternal skeleton resorbs to provide most of the calcium content of breast milk during lactation. These maternal adaptations also affect the presentation, diagnosis, and management of disorders of calcium and bone metabolism. Although some women may experience fragility fractures as a consequence of pregnancy or lactation, for most women, parity and lactation do not affect the long-term risks of low bone density, osteoporosis, or fracture.
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10
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Fenton TR, Lyon AW, Rose MS. Cord blood calcium, phosphate, magnesium, and alkaline phosphatase gestational age-specific reference intervals for preterm infants. BMC Pediatr 2011; 11:76. [PMID: 21884590 PMCID: PMC3179922 DOI: 10.1186/1471-2431-11-76] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 08/31/2011] [Indexed: 11/10/2022] Open
Abstract
Background The objective was to determine the influence of gestational age, maternal, and neonatal variables on reference intervals for cord blood bone minerals (calcium, phosphate, magnesium) and related laboratory tests (alkaline phosphatase, and albumin-adjusted calcium), and to develop gestational age specific reference intervals based on infants without influential pathological conditions. Methods Cross-sectional study. 702 babies were identified as candidates for this study in a regional referral neonatal unit. After exclusions (for anomalies, asphyxia, maternal magnesium sulfate administration, and death), relationships were examined between cord blood serum laboratory analytes (calcium, phosphate, magnesium, alkaline phosphatase, and albumin-adjusted calcium) with gestation age and also with maternal and neonatal variables using multiple linear regression. Infants with influential pathological conditions were omitted from the development of gestational age specific reference intervals for the following categories: 23-27, 28-31, 32-34, 35-36 and > 36 weeks. Results Among the 506 preterm and 54 terms infants included in the sample. Phosphate, magnesium, and alkaline phosphatase in cord blood serum decreased with gestational age, calcium increased with gestational age. Those who were triplets, small for gestational age, and those whose mother had pregnancy-induced hypertension were influential for most of the analytes. The reference ranges for the preterm infants ≥ 36 weeks were: phosphate 1.5 to 2.6 mmol/L (4.5 to 8.0 mg/dL), calcium: 2.1 to 3.1 mmol/L (8.3 to 12.4 mg/dL); albumin-adjusted calcium: 2.3 to 3.2 mmol/L (9.1 to 12.9 mg/dL); magnesium 0.6 to 1.0 mmol/L (1.4 to 2.3 mg/dL), and alkaline phosphatase 60 to 301 units/L. Conclusions These data suggest that gestational age, as well as potentially pathogenic maternal and neonatal variables should be considered in the development of reference intervals for preterm infants.
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Affiliation(s)
- Tanis R Fenton
- Department of Community Health Sciences, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, Canada.
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11
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Abstract
At the end of 2007, Time magazine listed the “benefits of vitamin D” as one of its top 10 medical breakthroughs for that year. Since then there has been a remarkable upsurge of interest in vitamin D, with new research advances seemingly published on a weekly basis. In particular, there has been increasing awareness of the variability of vitamin D status in populations across the globe and, significantly, a growing debate about the need for revised parameters for vitamin D supplementation. Although sub-optimal vitamin D is likely to be a widespread problem for 21stcentury societies, it is also clear that some groups are at much greater risk of low vitamin D status. Prominent amongst these are pregnant women and the aim of the following review article will be to discuss this problem in further detail with specific emphasis on its potential physiological and clinical impact.
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12
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Thandrayen K, Pettifor JM. Maternal vitamin D status: implications for the development of infantile nutritional rickets. Endocrinol Metab Clin North Am 2010; 39:303-20, table of contents. [PMID: 20511053 DOI: 10.1016/j.ecl.2010.02.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The mother is the major source of circulating 25-hydroxyvitamin D concentration in the young infant. Maternal vitamin D status is an important factor in determining the vitamin D status of the infant and their risk of developing vitamin D deficiency and infantile nutritional rickets. There is evidence that the current supplementation recommendations, particularly for pregnant and lactating women, are inadequate to ensure vitamin D sufficiency in these groups. A widespread and concerted effort is needed to ensure daily supplementation of breastfed and other infants at high risk with vitamin D 400 IU from birth and of pregnant women in high-risk communities with 2000 IU. Future studies are required to determine the optimal doses of vitamin D supplementation in pregnancy and during lactation, and for normalizing vitamin D stores in infancy to reduce the prevalence of infantile nutritional rickets. Operational research studies are needed to understand the best methods of implementing supplementation programs and the factors that are likely to impede their success.
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Affiliation(s)
- Kebashni Thandrayen
- MRC Mineral Metabolism Research Unit, Department of Pediatrics, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, South Africa
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13
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Kovacs CS. Vitamin D in pregnancy and lactation: maternal, fetal, and neonatal outcomes from human and animal studies. Am J Clin Nutr 2008; 88:520S-528S. [PMID: 18689394 DOI: 10.1093/ajcn/88.2.520s] [Citation(s) in RCA: 204] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
During pregnancy and lactation, mothers require significant amounts of calcium to pass on to the developing fetus and suckling neonate, respectively. Given the dependence of adult calcium concentrations and bone metabolism on vitamin D, one might anticipate that vitamin D sufficiency would be even more critical during pregnancy and lactation. However, maternal adaptations during pregnancy and lactation and fetal adaptations provide the necessary calcium relatively independently of vitamin D status. It is the vitamin D-deficient or insufficient neonate who is at risk of problems, including hypocalcemia and rickets. Due to poor penetrance of vitamin D and 25-hydroxyvitamin D [25(OH)D] into milk, exclusively breastfed infants are at higher risk of vitamin D deficiency than are formula-fed infants. Dosing recommendations for women during pregnancy and lactation might be best directed toward ensuring that the neonate is vitamin D-sufficient and that this sufficiency is maintained during infancy and beyond. A dose of vitamin D that provides 25(OH)D sufficiency in the mother during pregnancy should provide normal cord blood concentrations of 25(OH)D. Research has shown that during lactation, supplements administered directly to the infant can easily achieve vitamin D sufficiency; the mother needs much higher doses (100 mug or 4000 IU per day) to achieve adult-normal 25(OH)D concentrations in her exclusively breastfed infant. In addition, the relation (if any) of vitamin D insufficiency in the fetus or neonate to long-term nonskeletal outcomes such as type 1 diabetes and other chronic diseases needs to be investigated.
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Affiliation(s)
- Christophers S Kovacs
- Faculty of Medicine-Endocrinology, Memorial University of Newfoundland, St John's, Newfoundland, Canada.
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Korakaki E, Gourgiotis D, Aligizakis A, Manoura A, Hatzidaki E, Giahnakis E, Marmarinos A, Kalmanti M, Giannakopoulou C. Levels of bone collagen markers in preterm infants: relation to antenatal glucocorticoid treatment. J Bone Miner Metab 2007; 25:172-8. [PMID: 17447115 DOI: 10.1007/s00774-006-0742-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Accepted: 11/28/2006] [Indexed: 10/23/2022]
Abstract
Although the beneficial effects of antenatally administered glucocorticoids are well documented, data on the potential of adverse consequences are limited. The objective of this study was to determine the effects of antenatally administered glucocorticoids on biochemical markers of bone metabolism of 55 preterm infants with a gestational age of 24-34 weeks who were enrolled in the study. Neonates were divided into two groups according to antenatal exposure to corticosteroids. There were no significant differences between the groups in clinical characteristics and anthropometric variables. We studied blood levels of osteocalcin (OC), carboxy-terminal propeptide of type I procollagen (PICP), and carboxy-terminal telopeptide of type I collagen (ICTP) at the time of delivery, on postnatal day 10, and at 2 and 4 months of life. Comparing the groups, we found statistically significant reduction in PICP levels at birth in corticosteroid-exposed neonates (P < 0.05). The levels of bone markers increased progressively on the first days of life. There were no significant differences between groups in bone markers at 10 days or at 2 and 4 months of life. We found no significant difference for bone markers between groups of infants exposed to single or repeated maternal corticosteroid treatments. In summary, antenatal glucocorticoid treatments are suggested to have a negative impact on fetal bone formation as reflected by low PICP levels at birth. However, this negative effect on bone markers seems to be a temporary effect that subsides on the first days of life and afterward.
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Affiliation(s)
- Eftichia Korakaki
- Department of Neonatology, University of Crete, 37 Atlantithos St., 71305 Heraklion, Greece
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Nakano K, Iwamatsu T, Wang CM, Tarasima M, Nakayama T, Sasaki K, Tachikawa E, Noda N, Mizoguchi E, Osawa M. High bone turnover of type I collagen depends on fetal growth. Bone 2006; 38:249-56. [PMID: 16214433 DOI: 10.1016/j.bone.2005.07.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2005] [Revised: 07/19/2005] [Accepted: 07/28/2005] [Indexed: 11/26/2022]
Abstract
The bone metabolic processes of proliferation and differentiation in preterm and term newborns have yet to be fully elucidated. Seventy-four umbilical cord blood samples were collected from preterm and term newborns delivered at 27 to 42 gestational weeks (GWs). Carboxy-terminal propeptide of type I procollagen (PICP), pyridinoline cross-linked telopeptide domain of type I collagen (ICTP), alkaline phosphatase (ALP), and bone-specific alkaline phosphatase (BAP) were measured. Calcitonin (CT), estrogen (E2), intact parathyroid hormone, and insulin-like growth factor-I (IGF-I) were also examined in 20 or 23 randomly selected samples. We conducted cross-sectional regression analyses for bone metabolic markers, fetal growth markers including GWs, birth weight (BW), height (BH) and head circumference (HC), and bone related hormones. PICP and ICTP activities were very high, but decreased significantly with fetal growth based on GWs, BW, BH, and HC changes (GWs, BW, and BH to both PICP and ICTP, P < 0.0001; HC to ICTP, P < 0.0001; HC to PICP, P < 0.05), while BAP and ALP did not change significantly. E2 and CT both showed a significant positive correlation with Ca (P < 0.05), but neither hormone had any apparent correlation with PICP, ALP, BAP, or ICTP. These results suggest very active bone formation and resorption of type I collagen to be dependent on fetal growth and that fetal osteoblasts dominate the proliferation phase of development rather than the maturation phase. However, factors contributing to high bone turnover in the fetus remain to be elucidated.
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Affiliation(s)
- Kazutoshi Nakano
- Department of Pediatrics, Tokyo Women's Medical University, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
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Kovacs CS, Woodland ML, Fudge NJ, Friel JK. The vitamin D receptor is not required for fetal mineral homeostasis or for the regulation of placental calcium transfer in mice. Am J Physiol Endocrinol Metab 2005; 289:E133-44. [PMID: 15741244 DOI: 10.1152/ajpendo.00354.2004] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We utilized a vitamin D receptor (VDR) gene knockout model to study the effects of maternal and fetal absence of VDR on maternal fertility, fetal-placental calcium transfer, and fetal mineral homoeostasis. Vdr null mice were profoundly hypocalcemic, conceived infrequently, and had significantly fewer viable fetuses in utero that were also of lower body weight. Supplementation of a calcium-enriched diet increased the rate of conception in Vdr nulls but did not normalize the number or weight of viable fetuses. Among offspring of heterozygous (Vdr(+/-)) mothers (wild type, Vdr(+/-), and Vdr null fetuses), there was no alteration in serum Ca, P, or Mg, parathyroid hormone, placental (45)Ca transfer, Ca and Mg content of the fetal skeleton, and morphology and gene expression in the fetal growth plates. Vdr null fetuses did have threefold increased 1,25-dihydroxyvitamin D levels accompanied by increased 1alpha-hydroxylase mRNA in kidney but not placenta; a small increase was also noted in placental expression of parathyroid hormone-related protein (PTHrP). Among offspring of Vdr null mothers, Vdr(+/-) and Vdr null fetuses had normal ionized calcium levels and a skeletal ash weight that was appropriate to the lower body weight. Thus our findings indicate that VDR is not required by fetal mice to regulate placental calcium transfer, circulating mineral levels, and skeletal mineralization. Absence of maternal VDR has global effects on fetal growth that were partly dependent on maternal calcium intake, but absence of maternal VDR did not specifically affect fetal mineral homeostasis.
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Affiliation(s)
- Christopher S Kovacs
- Faculty of Medicine, Memorial University of Newfoundland, 300 Prince Philip Dr., St. John's, Newfoundland and Labrador, Canada.
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Kovacs CS, Kronenberg HM. Maternal-fetal calcium and bone metabolism during pregnancy, puerperium, and lactation. Endocr Rev 1997; 18:832-72. [PMID: 9408745 DOI: 10.1210/edrv.18.6.0319] [Citation(s) in RCA: 182] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- C S Kovacs
- Endocrine Unit, Massachusetts General Hospital, Boston 02114, USA
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Kovacs CS, Lanske B, Hunzelman JL, Guo J, Karaplis AC, Kronenberg HM. Parathyroid hormone-related peptide (PTHrP) regulates fetal-placental calcium transport through a receptor distinct from the PTH/PTHrP receptor. Proc Natl Acad Sci U S A 1996; 93:15233-8. [PMID: 8986793 PMCID: PMC26386 DOI: 10.1073/pnas.93.26.15233] [Citation(s) in RCA: 251] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
To determine the role of PTHrP in fetal calcium metabolism, blood calcium was measured in mice homozygous (HOM) for deletion of the PTHrP gene. On day 18.5 of gestation, ionized calcium and the maternal-fetal calcium gradient were significantly reduced in HOM PTHrP-ablated fetuses compared with that of their littermates. To assess the placental contribution to the effect of PTHrP, 45Ca and 51Cr-EDTA (as a blood diffusional marker) were administered by intracardiac injection to pregnant, heterozygous dams on day 17.5 of gestation. Five minutes after the injection, whole fetal 45Ca accumulation was significantly decreased in HOM PTHrP-ablated fetuses compared with that of their littermates. Next, two fetuses from each litter were injected in utero with fragments of PTHrP, PTH, or diluent 1 h before administering 45Ca and 51Cr to the dam. PTHrP-(1-86) and PTHrP-(67-86) significantly increased relative 45Ca accumulation in HOM PTHrP-ablated fetuses, but PTHrP-(1-34), PTH-(1-84), and the diluent had no effect. Finally, similar studies were performed on fetal mice that lacked the PTH/PTHrP receptor gene. Ionized calcium was significantly reduced in HOM PTH/PTHrP receptor-ablated fetuses. However, 5 min after maternal injection of 45Ca and 51Cr, relative accumulation of 45Ca was significantly increased in these fetuses. It was concluded that PTHrP is an important regulator of fetal blood calcium and placental calcium transport. In addition, the bioactivity of PTHrP for placental calcium transport is specified by a mid-molecular region that does not use the PTH/PTHrP receptor.
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Affiliation(s)
- C S Kovacs
- Endocrine Unit, Massachusetts General Hospital, Boston 02114, USA
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