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Abstract
Preterm infants are at risk of growth failure and metabolic bone disease due to insufficient nutrient supply in postnatal life. An ample provision of protein, energy, calcium and phosphates through parenteral or/and enteral nutrition is crucial for bone growth and mineralization. Additional vitamin D supplementation improves bone mineralization and enhance intestinal absorption of minerals.
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Phuapittayalert L, Saenganantakarn P, Supanpaiboon W, Cheunchoojit S, Hipkaeo W, Sakulsak N. Increasing CACNA1C expression in placenta containing high Cd level: an implication of Cd toxicity. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:24592-24600. [PMID: 27744593 DOI: 10.1007/s11356-016-7841-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 10/04/2016] [Indexed: 06/06/2023]
Abstract
Cadmium (Cd) has known to produce many adverse effects on organs including placenta. Many essential transporters are involved in Cd transport pathways such as DMT-1, ZIP as well as L-VDCC. Fourteen pregnant women participated and were divided into two groups: high and low Cd-exposed (H-Cd, L-Cd) groups on the basis of their residential areas, Cd concentrations in the blood (B-Cd), urine (U-Cd), and placenta (P-Cd). The results showed that the B-Cd and U-Cd were significantly increased in H-Cd group (p < 0.05). Interestingly, the P-Cd in H-Cd group was elevated (p < 0.05) and positively related to their B-Cd and U-Cd values (p < 0.05). However, the mean cord blood Cd (C-Cd) concentration in H-Cd group was not significantly increased about 2.5-fold when comparing to L-Cd group. To determine the Cd accumulation in placental tissues, metallothionein-1A (MT-1A) and metallothionein-2A (MT-2A) expressions were used as biomarkers. The results revealed that mean MT-1A and MT-2A mRNAs and MT-1/2 proteins were up-regulated in H-Cd group (p < 0.05). In addition, the Ca channel alpha 1C (CACNA1C) mRNA and protein expressions were noticeably elevated in H-Cd group (p < 0.05). From these findings, we suggested that CACNA1C might be implicated in Cd transport in human placenta.
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Affiliation(s)
- Laorrat Phuapittayalert
- Department of Anatomy, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand
- Department of Anatomy, School of Medical Science, University of Phayao, Phayao, 56000, Thailand
| | - Phisid Saenganantakarn
- Department of Anatomy, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand
| | - Wisa Supanpaiboon
- Department of Biochemistry, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand
| | - Supaporn Cheunchoojit
- Department of Public Health, Faculty of Science, Buriram Rajabhat University, Buriram, 31000, Thailand
| | - Wiphawi Hipkaeo
- Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40000, Thailand
| | - Natthiya Sakulsak
- Department of Anatomy, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand.
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Cantero MDR, Velázquez IF, Streets AJ, Ong ACM, Cantiello HF. The cAMP Signaling Pathway and Direct Protein Kinase A Phosphorylation Regulate Polycystin-2 (TRPP2) Channel Function. J Biol Chem 2015; 290:23888-96. [PMID: 26269590 DOI: 10.1074/jbc.m115.661082] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Indexed: 11/06/2022] Open
Abstract
Polycystin-2 (PC2) is a TRP-type, Ca(2+)-permeable non-selective cation channel that plays an important role in Ca(2+) signaling in renal and non-renal cells. The effect(s) of the cAMP pathway and kinase mediated phosphorylation of PC2 seem to be relevant to PC2 trafficking and its interaction with polycystin-1. However, the role of PC2 phosphorylation in channel function is still poorly defined. Here we reconstituted apical membranes of term human syncytiotrophoblast (hST), containing endogenous PC2 (PC2hst), and in vitro translated channel protein (PC2iv). Addition of the catalytic subunit of PKA increased by 566% the spontaneous PC2hst channel activity in the presence of ATP. Interestingly, 8-Br-cAMP also stimulated spontaneous PC2hst channel activity in the absence of the exogenous kinase. Either stimulation was inhibited by addition of alkaline phosphatase, which in turn, was reversed by the phosphatase inhibitor vanadate. Neither maneuver modified the single channel conductance but instead increased channel mean open time. PKA directly phosphorylated PC2, which increased the mean open time but not the single channel conductance of the channel. PKA phosphorylation did not modify either R742X truncated or S829A-mutant PC2iv channel function. The data indicate that the cAMP pathway regulates PC2-mediated cation transport in the hST. The relevant PKA site for PC2 channel regulation centers on a single residue serine 829, in the carboxyl terminus.
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Affiliation(s)
- María del Rocío Cantero
- From the Cátedra de Biofísica, Facultad de Odontología, Universidad de Buenos Aires, C1122AAH Buenos Aires, Argentina and
| | - Irina F Velázquez
- From the Cátedra de Biofísica, Facultad de Odontología, Universidad de Buenos Aires, C1122AAH Buenos Aires, Argentina and
| | - Andrew J Streets
- Kidney Genetics Group, Academic Nephrology Unit, The Henry Wellcome Laboratories for Medical Research, University of Sheffield Medical School, Sheffield S10 2RX, United Kingdom
| | - Albert C M Ong
- Kidney Genetics Group, Academic Nephrology Unit, The Henry Wellcome Laboratories for Medical Research, University of Sheffield Medical School, Sheffield S10 2RX, United Kingdom
| | - Horacio F Cantiello
- From the Cátedra de Biofísica, Facultad de Odontología, Universidad de Buenos Aires, C1122AAH Buenos Aires, Argentina and
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Pharande P, Pammi M, Collins CT, Zhou SJ, Abrams SA. Vitamin D supplementation for prevention of vitamin D deficiency in preterm and low birth weight infants. THE COCHRANE DATABASE OF SYSTEMATIC REVIEWS 2015. [DOI: 10.1002/14651858.cd011529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Pramod Pharande
- Royal Hospital for Women; Newborn Care Centre; Barker Street Randwick NSW Australia 2032
| | - Mohan Pammi
- Baylor College of Medicine; Section of Neonatology, Department of Pediatrics; 6621, Fannin, MC.WT 6-104 Houston Texas USA 77030
| | - Carmel T Collins
- Women's and Children's Health Research Institute, Flinders Medical Centre and Women's and Children's Hospital; Discipline of Paediatrics, The University of Adelaide; Child Nutrition Research Centre; Flinders Medical Centre Bedford Park South Australia Australia 5042
| | - Shao J Zhou
- Women's and Children's Hospital; School of Agriculture, Food & Wine, University of Adelaide; Women's and Children's Health Research Institute; 72 King William Road North Adelaide Australia 5006
| | - Steven A Abrams
- Children's Nutrition Research Center; Neonatology and USDA/ARS; 1100 Bates Street Room 7066 Houston Texas USA 77030
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Abstract
OBJECTIVES Bone mineralisation in preterm infants is related to the supply of calcium (Ca) and phosphorus (P). We increased the amount of minerals in parenteral nutrition (PN) for preterm infants and evaluated postnatal Ca and P metabolism in relation to mineral and vitamin D (vitD) intake. METHODS Preterm infants, included on their first day of life, received standard PN, providing a maximum Ca/P intake of 3/1.92 mmol · kg(-1) · day(-1) on day 3. Ca/P content of formula was 2.5/1.6 mmol/dL, and fortified human milk was 2.4/1.95 mmol/dL. PN supplied 80 IU · kg(-1) · day(-1) vitD. Formula and fortified human milk contained 200 IU/dL of vitD. During a 5-week period, serum concentrations and urinary excretion of Ca/P were registered and related to the intake of minerals and vitD. RESULTS During 12 months, 79 infants (mean gestational age 29.8 ± 2.2 weeks, mean birth weight 1248 ± 371 g) were included. The recommended intake for minerals was achieved by day 5 and for vitD by 4 weeks. Infants developed hypercalcaemia, hypercalciuria, and hypophosphataemia during the first postnatal week, leading to the additional P supplementation in 49 infants. The renal tubular reabsorption of P was >95% until day 9 but decreased <70% after the second week. Alkaline phosphatase was normal at birth, increased to a maximum of 450 IU/L by day 14, and remained above the normal range for the remaining period. CONCLUSIONS Parenteral intake of P appeared to be too low, leading to mineral imbalances in the early postnatal period, and vitD intake was also below recommendations.
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Cantero MDR, Cantiello HF. Calcium transport and local pool regulate polycystin-2 (TRPP2) function in human syncytiotrophoblast. Biophys J 2014; 105:365-75. [PMID: 23870258 DOI: 10.1016/j.bpj.2013.05.058] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 05/16/2013] [Accepted: 05/30/2013] [Indexed: 01/26/2023] Open
Abstract
Polycystin-2 (PC2, TRPP2) is a Ca(2+)-permeable, nonselective cation channel implicated in Ca(2+) transport and epithelial cell signaling. Although PC2 may contribute to Ca(2+) transport in human term placenta, the regulatory mechanisms associated with Ca(2+) handling in this tissue are largely unknown. In this work we assessed the regulation by Ca(2+) of PC2 channel function from a preparation of apical membranes of human syncytiotrophoblast (PC2hst) reconstituted in a lipid bilayer system. Addition of either EGTA or BAPTA to the cis hemi-chamber, representing the cytoplasmic domain of the channel, and lowering Ca(2+) to ∼0.6-0.8 nM, inhibited spontaneous PC2hst channel activity, with a time response dependent on the chelator tested. EGTA reduced PC2hst channel currents by 86%, with a t1/2 = 3.6 min, whereas BAPTA rapidly and completely (100%) eliminated channel activity with a t1/2 = 0.8 min. Subsequent titration with Ca(2+) reversed the inhibition, which followed a Hill-type function with apparent dissociation constants of 1-5 nM, and 4 Ca(2+) binding sites. The degree of inhibition by the cis Ca(2+) chelator largely depended on increasing trans Ca(2+). This was consistent with measurable Ca(2+) transport through the channel, feeding the regulatory sites in the cytoplasmic domain. Interestingly, the reconstituted in vitro translated PC2 (PC2iv) was completely insensitive to Ca(2+) regulation, suggesting that the regulatory sites are not intrinsic to the channel protein. Our findings demonstrate the presence of a Ca(2+) microdomain largely accessible through the channel that controls PC2 function in human syncytiotrophoblast of term placenta.
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Affiliation(s)
- María Del Rocío Cantero
- Cátedra de Biofísica, Facultad de Odontología, Universidad de Buenos Aires, Buenos Aires, Argentina
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Yang H, Kim TH, An BS, Choi KC, Lee HH, Kim JM, Jeung EB. Differential expression of calcium transport channels in placenta primary cells and tissues derived from preeclamptic placenta. Mol Cell Endocrinol 2013; 367:21-30. [PMID: 23267838 DOI: 10.1016/j.mce.2012.12.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 11/13/2012] [Accepted: 12/14/2012] [Indexed: 12/24/2022]
Abstract
Preeclampsia is a pregnancy-specific disease characterized by hypertension, proteinuria, and oxidative stress in the placenta. During the last trimester of gestation, calcium (Ca(2+)) transport from mother to fetus increases dramatically in response to the increased demand for Ca(2+) caused by bone mineralization in the fetus. Ca(2+) supplementation can significantly reduce the incidence and severity of preeclampsia or delay its onset. Ca(2+) transport channels (CTCs) include transient receptor potential vanilloid 6 (TRPV6), plasma membrane Ca(2+) ATPase (PMCA1), and Na(+)/Ca(2+) exchangers (NCKX3 or NCX1). We hypothesized that trans-placental Ca(2+) exchange in preeclamptic trophoblasts may be compensated for successful fetal bone mineralization. The roles of cell membrane channels (TRPV6, PMCA1, NCKX3 and NCX1) were examined in placental primary cells and in normotensive and preeclamptic placentas. The biomarker gene for preeclampsia, soluble fms-like tyrosine kinase-1 (sFLT1) or marker for oxygen-sensitive gene, hypoxia-sensitive inducible factor 1α (HIF-1α), were up-regulated in the preeclamptic placentas and hypoxic cells. The detection of sFLT1 and HIF-1α genes demonstrated that our experimental conditions were suitable to verify a preeclamptic condition. In women experiencing preterm labor, CTC expressions was found to be increased in the fetal and maternal regions of the preeclamptic placenta compared to the observed in normotensive placenta. During term labor, TRPV6 and PMCA1 were highly expressed in the fetal and maternal sections of preeclamptic placenta, while the expression of NCKX3 and NCX1 was reduced. In addition, the expression of CTCs was altered in hypoxia-stressed placental cells. Taken together, our findings demonstrated that the expression of CTCs was regulated by hypoxia stress in placenta tissues and cells, suggesting that our experimental in vitro hypoxic conditions were similar to those of preeclampsia. Furthermore, impaired Ca(2+) metabolism found in preeclamptic syncytiotrophoblasts was resulted from hypoxic stress, which may induce expression of Ca(2+) transport proteins in the placenta to maintain the balance between maternal and fetal Ca(2+) demand during pregnancy.
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Affiliation(s)
- Hyun Yang
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea
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Haché S, Takser L, LeBellego F, Weiler H, Leduc L, Forest JC, Giguère Y, Masse A, Barbeau B, Lafond J. Alteration of calcium homeostasis in primary preeclamptic syncytiotrophoblasts: effect on calcium exchange in placenta. J Cell Mol Med 2011; 15:654-67. [PMID: 20178461 PMCID: PMC3922387 DOI: 10.1111/j.1582-4934.2010.01039.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Preeclampsia (PE) is characterized by maternal hypertension, proteinuria, oedema and, in 30% of cases, by intrauterine growth retardation. Causes are still unknown; however, epidemiological and clinical studies have suggested alterations in maternal calcium metabolism. We suggested that in PE, calcium transport by the syncytiotrophoblast (ST) is disturbed. From total placental tissues, we studied the expression of: calcium channels (TRPV5, TRPV6 [transient receptor potential vanilloid]), calcium binding proteins (CaBP-9K, CaBP-28K), plasma membrane calcium ATPase (PMCA)1,2,3,4 pumps, ATP synthase, genes implicated in Ca2+ release [inositol-1,4,5-triphosphate receptor (IP3R)1,2,3; Ryanodine receptor (RyR)1,2,3] and replenishment (SERCA1,2,3 [sarcoendoplasmic reticulum Ca2+ ATPases]) from endoplasmic reticulum, channels implicated in mitochondrial Ca2+ accumulation (VDAC1,2,3 [voltage-dependent anion channels]) and a marker of oxidative stress (hOGG1 [Human 8-oxoguanine-DNA glycosylase 1]), as well as the influence of these variations on calcium transport in primary ST cultures. The mRNA and protein levels were thereby examined by real-time PCR and Western blot analysis, respectively, in two different groups of pregnant women with similar gestational age: a normal group (n= 16) and a PE group (n= 8), diagnosed by a clinician. Our study showed a significant decrease in calcium transport by the ST cultured from preeclamptic placentas. We found a significant (P < 0.05) decrease in mRNA levels of TRPV5, TRPV6, CaBP-9K, CaBP-28K, PMCA1, PMCA4, ATP synthase, IP3R1, IP3R2, RyR1, RyR2 and RyR3 in PE group compared to normal one. We also noted a significant decrease in protein levels of TRPV5, TRPV6, CaBP-9K, CaBP-28K and PMCA1/4 in PE group. In contrast, SERCA1, SERCA2, SERCA3, VDAC3 and hOGG1 mRNA expressions were significantly increased in PE placentas. Calcium homeostasis and transport through placenta is compromised in preeclamptic pregnancies and it appears to be affected by a lack of ATP and an excess of oxidative stress.
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Affiliation(s)
- S Haché
- Biomed Research Center, Department of Biological Sciences, University of Quebec at Montreal, Quebec, Canada
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Baczyk D, Kingdom JCP, Uhlén P. Calcium signaling in placenta. Cell Calcium 2011; 49:350-6. [PMID: 21236488 DOI: 10.1016/j.ceca.2010.12.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 12/07/2010] [Accepted: 12/08/2010] [Indexed: 12/19/2022]
Abstract
The placenta sustains the developing fetus throughout gestation and its major functions include nutrition, gas and waste exchange via a variety of passive or active mechanisms. Up to 30 g of calcium (Ca(2+)) actively crosses the trophoblast layer during human pregnancy. The Ca(2+) ion not only plays an important role for skeletal development but is also an essential second messenger. This review is intended to highlight the implications of Ca(2+) signaling during reproduction and specifically placentation. Initially, a Ca(2+) wave induces fertilization of the oocyte. The intracellular Ca(2+) concentration is key for the blastocyst implantation, proper placental development and function. Current knowledge of many proteins involved in placental Ca(2+) regulation and their function in pathologic conditions is largely limited. Recent studies, however, point to alterations in Ca(2+) homeostasis in placental pathologies such as pre-eclampsia (PE) and intrauterine growth restriction (IUGR). A broader understanding of the role of Ca(2+) signaling during human reproduction may offer insight into impaired pregnancy outcomes.
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Affiliation(s)
- Dora Baczyk
- Research Centre for Women's and Infants' Health (RCWIH) at the Samuel Lunenfeld Research Institute of Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
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Wong JC, McDougal AR, Tofan M, Aulakh J, Pineault M, Chessex P. Doubling Calcium and Phosphate Concentrations in Neonatal Parenteral Nutrition Solutions Using Monobasic Potassium Phosphate. J Am Coll Nutr 2006; 25:70-7. [PMID: 16537340 DOI: 10.1080/07315724.2006.10719517] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Premature infants require high intakes of Ca and P to mimic fetal accretion rates. With the current phosphate salt used, adequate amounts cannot be provided due to the precipitation of Ca and P in TPN solutions. OBJECTIVE To compare monobasic potassium phosphate (monobasic regimen) and monobasic plus dibasic potassium phosphate (dibasic regimen) on calcium phosphate solubility in 5 amino acid products, and to determine whether solubility differences observed in these products can be explained by buffering capacity. METHODS TPN solutions were prepared according to standard clinical practice. The following amino acid products were used at 3% concentrations: Primene, Vamin N, TrophAmine, Aminosyn-PF, and Travasol. Dextrose 10%, standard electrolytes, heparin, vitamins and trace elements were added. Calcium (as gluconate) and phosphate (as monobasic or dibasic regimen) were added in one-to-one molar ratios from 0-45 mmol/L. Solutions were inspected macroscopically and microscopically for precipitation under three conditions: immediately, 24 h after preparation at room temperature, and 3 h later in a 37 degrees C water bath. Buffering capacity was determined for each amino acid product by titrating with standardized 0.1 M NaOH. RESULTS Variations in Ca:P solubility and buffer capacity exist between amino acid solutions. With Primene and Vamin no macroscopic or microscopic precipitation was detected up to 45 mmol/L using monobasic regimen, compared to 25 mmol/L using dibasic regimen with Trophamine. Buffer capacity did not account for the solubility differences observed between the five amino acid products, which were related to the pH of the final solution. CONCLUSIONS These data will allow clinicians to double the current concentrations of calcium and phosphate in neonatal TPN solutions using monobasic regimen. Although this is particularly relevant to situations when fluid intake is restricted, the effect of the acid load needs to be investigated in extremely low birth weight infants.
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Affiliation(s)
- Joyce C Wong
- Department of Pharmacy, Children's and Women's Health Centre of BC, 4480 Oak Street, Vancouver, British Columbia V6H 3V4, Canada
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Lafond J, Simoneau L. Calcium Homeostasis in Human Placenta: Role of Calcium‐Handling Proteins. INTERNATIONAL REVIEW OF CYTOLOGY 2006; 250:109-74. [PMID: 16861065 DOI: 10.1016/s0074-7696(06)50004-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The human placenta is a transitory organ, representing during pregnancy the unique connection between the mother and her fetus. The syncytiotrophoblast represents the specialized unit in the placenta that is directly involved in fetal nutrition, mainly involving essential nutrients, such as lipids, amino acids, and calcium. This ion is of particular interest since it is actively transported by the placenta throughout pregnancy and is associated with many roles during intrauterine life. At term, the human fetus has accumulated about 25-30 g of calcium. This transfer allows adequate fetal growth and development, since calcium is vital for fetal skeleton mineralization and many cellular functions, such as signal transduction, neurotransmitter release, and cellular growth. Thus, there are many proteins involved in calcium homeostasis in the human placenta.
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Affiliation(s)
- Julie Lafond
- Laboratoire de Physiologie Materno Foetale, Centre de recherche BioMed, Université du Québec à Montréal, Montréal, Canada, H3C 3P8
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Belkacemi L, Bédard I, Simoneau L, Lafond J. Calcium channels, transporters and exchangers in placenta: a review. Cell Calcium 2005; 37:1-8. [PMID: 15541458 DOI: 10.1016/j.ceca.2004.06.010] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2004] [Revised: 06/28/2004] [Accepted: 06/29/2004] [Indexed: 11/25/2022]
Abstract
Calcium (Ca2+) entry in cells is crucial for development and physiology of virtually all cell types. It acts as an intracellular (second) messenger to regulate a diverse array of cellular functions, from cell division and differentiation to cell death. Among candidates for Ca2+ entry in cells are-voltage-dependant Ca2+ channels (VDCCs), transient receptor potential (TRP)-related Ca2+ channels and store-operated Ca2+ (SOC) channels. Plasma membrane Ca2+-ATPases (PMCA) and Na+/Ca2+ exchanger (NCX) are mainly responsible for Ca2+ extrusion. These different Ca2+channels/transporters and exchangers exhibit specific distribution and physiological properties. During pregnancy, the syncytiotrophoblast layer of the human placenta transfers as much as 30 g of Ca2+ from the mother to the fetus, especially in late gestation where Ca2+ transport through different channels must increase in response to the demands of accelerating bone mineralization of the fetus. The identification and characterization of the different Ca2+ channels/transporters and exchangers on the brush-border membrane (BBM) facing the maternal circulation, and the basal plasma membrane (BPM) facing the fetal circulation; placental membrane of the syncytiotrophoblasts have been the focus of numerous studies. This review discusses current views in this field regarding localization and functions during transcellular Ca2+ entry and extrusion from cells particularly in the placenta.
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Affiliation(s)
- Louiza Belkacemi
- Laboratoire de Physiologie Materno-Foetale, Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succursale 'Centre-Ville'Montréal, Montréal, Québec, Canada H3C 3P8
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Lafond J, Hamel A, Takser L, Vaillancourt C, Mergler D. Low environmental contamination by lead in pregnant women: effect on calcium transfer in human placental syncytiotrophoblasts. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2004; 67:1069-1079. [PMID: 15205024 DOI: 10.1080/15287390490452263] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
There is an extensive literature on the neurotoxic effects of lead (Pb) on the developing fetus; however, little is known about the mechanisms of action at low levels. Heavy metals are known to affect calcium (Ca2+) homeostasis through perturbation of Ca2+ channels and pumps and interference with protein kinase C (PKC) and Ca2+ binding protein (CaBP). During pregnancy, placental Ca2+ exchange is one of the most important mechanisms for fetal survival. This ion is an essential element for healthy fetal growth and development. The aim of the present study was to determine the influence of low maternal blood Pb levels on Ca2+ levels in serum and placenta and placental Ca2+ transfer. Blood samples (maternal and cord) and placental tissue were obtained at birth from 30 women residing in southwest Quebec. Total Ca2+ and Pb levels were measured in maternal and umbilical cord samples and placental tissue at term. The placentas were taken for trophoblast cell isolation and Ca2+ incorporation kinetic experiments. Data showed that Ca2+ in maternal blood did not influence Ca2+ uptake by syncytiotrophoblast. However, although maternal and cord blood Pb levels were low, maternal blood Pb concentration was significantly linked to a decrease in Ca2+ uptake by syncytiotrophoblast. This suggests that exposure to very levels of Pb significantly modifies Ca2+ transfer in syncytiotrophoblasts.
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Affiliation(s)
- Julie Lafond
- Laboratoire de Physiologie Materno-Foetale and Centre d'étude des interactions biologiques entre la santé et l'environnement (CINBOISE), Département des Sciences Biologiques, Université du Québec à Montréal, Québec, Canada.
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Picaud JC, Boucher P, Lapillonne A, Berthouze M, Delvin E, Boehm G, Claris O, Laborie S, Reygrobellet B, Lapillonne H, Glorieux FH, Salle BL. Influence of dietary cholesterol on vitamin d metabolism in formula-fed preterm neonates. J Pediatr Gastroenterol Nutr 2002; 35:180-4. [PMID: 12187294 DOI: 10.1097/00005176-200208000-00014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVES Supplementation of preterm formulas with cholesterol could help to mimic the fat composition of human milk. However, this could possibly influence vitamin D 25-hydroxylation because this reaction is catalyzed in part by the mitochondrial cytochrome P-450, the enzyme responsible for the 27-hydroxylation of cholesterol. The purpose of this study was to verify whether the addition of cholesterol to preterm formulas could interfere with vitamin D metabolism in preterm neonates. METHODS In a prospective study, 30 preterm neonates were randomly assigned to a low (< 0.03 g/L), medium (0.15 g/L), or high (0.30 g/L) cholesterol-content preterm formula until theoretical term (i.e., 40 weeks post-conceptional age). Anthropometric data and serum hydroxy-vitamin D and 1,25 dihydroxy-vitamin D concentrations were measured at study entry and theoretical term. In a subgroup of 14 subjects, serum cholesterol and lymphocyte 3-hydroxy-3-methylglutaryl coenzyme A reductase mRNA were also assessed. RESULTS (median [25, 75 centiles]): At theoretical term, there were no significant differences in serum hydroxy-vitamin D concentrations among the three groups, even after adjustment for confounding variables (65 [50, 78] nmol/L, 79 [59, 86] nmol/L, and 67 [43, 103] nmol/L, respectively, = 0.65) or 1,25 dihydroxy-vitamin D ( = 0.88). Furthermore, there were no significant differences in 3-hydroxy-3-methylglutaryl coenzyme A reductase mRNA copy numbers. CONCLUSIONS In preterm neonates fed formulas with a cholesterol content similar to or higher than that of human milk, we did not observe deleterious effects on vitamin D metabolism. However, long-term effects of cholesterol supplementation require further studies.
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Affiliation(s)
- Jean-Charles Picaud
- Department of Neonatology, Human Nutrition Research Center, Hospital E. Herriot, Lyon, France.
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Abstract
Placental transfer of maternal calcium (Ca(2+)) is a crucial process for fetal development although the biochemical mechanisms responsible for this transfer are largely unknown. We have investigated the characteristics of Ca(2+)uptake by the human placental trophoblast cell line BeWo. The kinetics studies revealed an active extracellular Ca(2+)uptake by BeWo cells, which was rapid in the first 2 min (initial velocity (V(i)) of 4.17+/-0.25 nmol/mg/min), and showed a subsequent plateau. Uptake experiments performed at V(i)with increasing concentrations of Ca(2+)resulted in a typical saturation curve (K(m)of 0.54+/-0.07 m m and V(max)of 7.07+/-0.28 nmol/mg protein/min). Lowering the pH of the incubation medium from 7.4 to 5.5 led to Ca(2+)uptake inhibition of 40-50 per cent. The presence of voltage-sensitive (l -type) Ca(2+)channels in BeWo cells was demonstrated by Western blot. Therefore, the implication of such channels in basal Ca(2+)uptake of BeWo cells was investigated. Cell depolarization with extracellular high potassium concentration (40 m m), and hyperpolarization with extracellular high chloride concentration (60 m m) or with valinomycin (10 microm) did not influence the basal Ca(2+)uptake of BeWo cells. The L-type Ca(2+)channel modulators (Bay K 8644 and Nitrendipine) had no effect on the Ca(2+)uptake. An antagonist of receptor-mediated, store-operated and voltage-gated Ca(2+)channels (SKF-96365) also did not modulate the Ca(2+)uptake of BeWo cells. Therefore, our results indicate that the basal Ca(2+)uptake of BeWo cells is inhibited by lowering pH of the incubation medium, is voltage independent, and is not influenced by l -type Ca(2+)channel and capacitative Ca(2+)conductance modulators.
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Affiliation(s)
- R Moreau
- Laboratoire de Physiologie materno-foetale, Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, Québec, Canada, H3C 3P8
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Salle BL, Delvin EE, Lapillonne A, Bishop NJ, Glorieux FH. Perinatal metabolism of vitamin D. Am J Clin Nutr 2000; 71:1317S-24S. [PMID: 10799409 DOI: 10.1093/ajcn/71.5.1317s] [Citation(s) in RCA: 185] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
During pregnancy, maternal serum concentrations of 25-hydroxyvitamin D, the circulating form of vitamin D, correlate with dietary vitamin D intake. Maternal serum concentrations of 1,25-dihydroxyvitamin D, the hormonal circulating and active form of vitamin D, are elevated during pregnancy; 1,25-dihydroxyvitamin D is synthesized mainly by the decidual cells of the placenta and allows for increased calcium absorption. The fetus is entirely dependent on the mother for its supply of 25-hydroxyvitamin D, which is believed to cross the placenta. Hypocalcemia and increased parathyroid hormone secretion induce synthesis of 1,25-dihydroxyvitamin D after birth in both full-term and preterm neonates. Nevertheless, serum concentrations of 25-hydroxyvitamin D are a rate-limiting factor in the synthesis of 1,25-dihydroxyvitamin D. In vitamin D-replete infants, circulating 1,25-dihydroxyvitamin D concentrations are higher than those observed in older infants. In countries where dairy products are not routinely supplemented with vitamin D, maternal vitamin D supplementation during pregnancy is necessary. However, there is no indication for the use of pharmacologic doses of vitamin D or its metabolites in the perinatal period.
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Affiliation(s)
- B L Salle
- Department of Neonatology and Human's Nutrition Center, Hôpital Edouard Herriot, Lyon, France.
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Rigo J, De Curtis M, Pieltain C, Picaud JC, Salle BL, Senterre J. Bone mineral metabolism in the micropremie. Clin Perinatol 2000; 27:147-70. [PMID: 10690569 DOI: 10.1016/s0095-5108(05)70011-7] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Environmental factors, nutritional supplies, hormonal status, diseases, and treatments appear to affect postnatal skeletal growth and mineralization in VLBW infants. Compared with their term counterparts, ELBW infants are at risk of postnatal growth deficiency and osteopenia at the time of hospital discharge. From recent data, DXA is becoming one of the reference techniques to evaluate mineral status, whole-body composition, and effects of dietary manipulations on weight gain composition and mineral accretion in preterm infants. Weight gain and length increases need to be evaluated carefully during the first weeks of life, in the intensive care unit and out of it, in the step down unit. Nutritional survey is required to improve the nutritional supply and to maximize linear growth. As the critical epoch of growth extends, during the first weeks or months after discharge, follow-up and nutritional support need to be provided during the first years to promote early catch-up growth and mineralization. Further studies need to determine precisely the most optimal feeding regimen during this period but also need to evaluate the long-term implications of such a policy on stature, peak bone mass, and general health at adulthood.
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Affiliation(s)
- J Rigo
- Department of Pediatrics, University of Liège, CHR Citadelle, Belgium.
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Lockitch G. Perinatal and Pediatric Nutrition. Clin Lab Med 1993. [DOI: 10.1016/s0272-2712(18)30445-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Palacios J, Rodríguez S, Rodríguez JI. Intra-uterine long bone growth in small-for-gestational-age infants. Eur J Pediatr 1992; 151:304-7. [PMID: 1499585 DOI: 10.1007/bf02072235] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
To better understand the intra-uterine bone modelling and remodelling process in small-for-gestational-age (SGA) newborn infants, long bone growth was studied using postmortem X-ray films in a group of such infants (n = 34). Bone length, diaphyseal diameter, medullary diameter, cortical thickness, cortical area, the Barnett-Nordin index, and the percentage of cortical area were determined in femur, tibia, and humerus. A separate group of appropriate-for-gestational-age (AGA) newborn infants (n = 146) was used as controls. Length and cortical bone mass in all three bones were significantly lower in SGA infants than in AGA infants. Decreased cortical bone mass in SGA infants was the result of decreased diaphyseal diameters and increased medullary diameters. Similar results were obtained when SGA infants were subclassified as preterm and term and compared with the control group of AGA infants. Bone lengths and diaphyseal diameters in SGA infants did not differ from those observed in a weight-matched control group of AGA infants although the latter were younger by 4 weeks' gestation. However, the cortical bone mass was lower than in the control group because of the relative greater medullary diameters in all three long bones in the SGA infants. Our present results indicate that reduced cortical bone mass in SGA infants is a mixed growth modelling and remodelling dependent process.
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Affiliation(s)
- J Palacios
- Department of Pathology, La Paz Hospital, Madrid, Spain
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Chessex P, Pineault M, Brisson G, Delvin EE, Glorieux FH. Role of the source of phosphate salt in improving the mineral balance of parenterally fed low birth weight infants. J Pediatr 1990; 116:765-72. [PMID: 2109792 DOI: 10.1016/s0022-3476(05)82669-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Because the monobasic potassium phosphate salt (monobasic) improves the solubility of calcium and phosphorus in amino acid plus dextrose solutions, compared with the current mixtures of monobasic plus dibasic salts (dibasic), we tested the bioavailability and clinical effects of monobasic in 16 parenterally fed low birth weight infants at standard (n = 8) and high levels (n = 8) of mineral intakes. A constant infusion of macronutrients and vitamin D was provided in a crossover design of two four-day periods. With standard intakes of calcium (35 mg/kg/day, 0.9 mmol/kg/day) and phosphorus (30 mg/kg/day, 1 mmol/kg/day), there was no difference between monobasic and dibasic regimens on balance data or plasma biochemical monitoring (calcium, phosphorus, pH, carbon dioxide pressure, base excess, 1,25-dihydroxyvitamin D, 25-hydroxyvitamin D). With the use of the monobasic regimen, the mineral intakes were doubled without precipitation in the infusate: calcium, 70 mg/kg/day (1.8 mmol/kg/day), and phosphorus, 55 mg/kg/day (1.7 mmol/kg/day). This led to increased apparent retention of both calcium (63 +/- 5 mg/kg/day, 1.58 +/- 0.12 mmol/kg/day) and phosphorus (52 +/- 4 mg/kg/day, 1.67 +/- 0.14 mmol/kg/day) compared with that for standard levels of mineral intake. The improvement of calcium-phosphorus balance was accompanied by more severe calciuria (9 +/- 2 mg/kg/day, 0.2 +/- 0.05 mmol/kg/day) and by metabolic compensation for an increased acid load. In addition to the possibility of exceeding the buffering capacity of the infant, this relative acidosis could also be evidence of improved bone mineralization.
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Affiliation(s)
- P Chessex
- Centre de recherche, Hôpital Sainte-Justine, Montreal, Quebec, Canada
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