Bone metabolism in the fetus and neonate

Biomarkers and Biochemical Indicators to Evaluate Bone Metabolism in Preterm Neonates

The purpose of the present study was to evaluate the concentrations of some bone turnover markers in preterm neonates with uncomplicated clinical course in the first month of life. Samples from 13 preterm neonates were collected at three different times: at birth (T0) from umbilical cord blood (UCB); and at 15 (T1) and 30 (T2) days of life from peripheral blood (PB). The concentrations of calcium (Ca), phosphate (P), total alkaline phosphatase (ALP), Collagen Type 1 Amino-terminal Propeptide (PINP), osteocalcin (OC), Collagen Type 1 Carboxyl-Terminal Telopeptide (CTX) and Leptin were assessed. A statistically significant difference for ALP concentration at birth versus T1 and T2 was found. An evident increase in the median concentrations of CTX, OC and PINP from T0 to T2 were observed. A significant difference was also found for Leptin concentration at T0 compared to T1. In preterm infants, in the absence of acute or chronic medical conditions and without risk factors for metabolic bone disease (MBD) of prematurity, there is a significant increase in bone turnover markers during the first month of life. The knowledge of the variations in these markers in the first weeks of life, integrated by the variations in the biochemical indicators of bone metabolism, could help in recognizing any conditions at risk of developing bone diseases.

Molecular mechanisms of human overgrowth and use of omics in its diagnostics: chances and challenges

Overgrowth disorders comprise a group of entities with a variable phenotypic spectrum ranging from tall stature to isolated or lateralized overgrowth of body parts and or organs. Depending on the underlying physiological pathway affected by pathogenic genetic alterations, overgrowth syndromes are associated with a broad spectrum of neoplasia predisposition, (cardio) vascular and neurodevelopmental anomalies, and dysmorphisms. Pathologic overgrowth may be of prenatal or postnatal onset. It either results from an increased number of cells (intrinsic cellular hyperplasia), hypertrophy of the normal number of cells, an increase in interstitial spaces, or from a combination of all of these. The underlying molecular causes comprise a growing number of genetic alterations affecting skeletal growth and Growth-relevant signaling cascades as major effectors, and they can affect the whole body or parts of it (mosaicism). Furthermore, epigenetic modifications play a critical role in the manifestation of some overgrowth diseases. The diagnosis of overgrowth syndromes as the prerequisite of a personalized clinical management can be challenging, due to their clinical and molecular heterogeneity. Physicians should consider molecular genetic testing as a first diagnostic step in overgrowth syndromes. In particular, the urgent need for a precise diagnosis in tumor predisposition syndromes has to be taken into account as the basis for an early monitoring and therapy. With the (future) implementation of next-generation sequencing approaches and further omic technologies, clinical diagnoses can not only be verified, but they also confirm the clinical and molecular spectrum of overgrowth disorders, including unexpected findings and identification of atypical cases. However, the limitations of the applied assays have to be considered, for each of the disorders of interest, the spectrum of possible types of genomic variants has to be considered as they might require different methodological strategies. Additionally, the integration of artificial intelligence (AI) in diagnostic workflows significantly contribute to the phenotype-driven selection and interpretation of molecular and physiological data.

Measurement of Calprotectin and PTH in the Amniotic Fluid of Early Second Trimester Pregnancies and Their Impact on Fetuses with Growth Disorders: Are Their Levels Related to Oxidative Stress?

Background: During the early stages of human fetal development, the fetal skeleton system is chiefly made up of cartilage, which is gradually replaced by bone. Fetal bone development is mainly regulated by the parathyroid hormone parathormone (PTH) and PTH-related protein, with specific calprotectin playing a substantial role in cell adhesion and chemotaxis while exhibiting antimicrobial activity during the inflammatory osteogenesis process. The aim of our study was to measure the levels of PTH and calprotectin in early second trimester amniotic fluid and to carry out a comparison between the levels observed among normal full-term pregnancies (control group) and those of the groups of embryos exhibiting impaired or enhanced growth. Methods: For the present prospective study, we collected amniotic fluid samples from pregnancies that underwent amniocentesis at 15 to 22 weeks of gestational age during the period 2021-2023. Subsequently, we followed up on all pregnancies closely until delivery. Having recorded fetal birthweights, we then divided the neonates into three groups: small for gestational age (SGA), appropriate for gestational age (AGA), and large for gestational age (LGA). Results: In total, 64 pregnancies, including 14 SGA, 10 LGA, and 40 AGA fetuses, were included in our study. Both substances were detected in early second trimester amniotic fluid in both groups. Concentrations of calprotectin differed significantly among the three groups (p = 0.033). AGA fetuses had a lower mean value of 4.195 (2.415-6.425) IU/mL, whereas LGA fetuses had a higher mean value of 6.055 (4.887-13.950) IU/mL, while SGA fetuses had a mean value of 5.475 (3.400-9.177) IU/mL. Further analysis revealed that only LGA fetuses had significantly higher calprotectin concentrations compared to AGA fetuses (p = 0.018). PTH concentration was similar between the groups, with LGA fetuses having a mean value of 13.18 (9.51-15.52) IU/mL, while SGA fetuses had a mean value of 14.18 (9.02-16.00) IU/mL, and AGA fetuses had similar concentrations of 13.35 (9.05-15.81) IU/mL. The differences in PTH concentration among the three groups were not statistically significant (p = 0.513). Conclusions: Calprotectin values in the amniotic fluid in the early second trimester were higher in LGA fetuses compared to those in the SGA and AGA categories. LGA fetuses can possibly be in a state of low-grade chronic inflammation due to excessive fat deposition, causing oxidative stress in LGA fetuses and, eventually, the release of calprotectin. Moreover, PTH concentrations in the amniotic fluid of early second trimester pregnancies were not found to be statistically correlated with fetal growth abnormalities in either LGA or SGA fetuses. However, the early time of collection and the small number of patients in our study should be taken into account.

Effects of feeding a negative dietary cation and anion difference diet to twin-bearing Merino ewes in late gestation on parturition outcomes

In Australia, dystocia is responsible for 53% of lamb mortalities, and calcium deficiencies may be a contributing factor. A negative dietary cation-anion difference (DCAD) diet can increase calcium concentrations in sheep. Therefore, this study aimed to investigate the effects of a negative DCAD diet on metabolic state, mineral status, and parturition duration in ewes compared with those fed a positive DCAD diet. At approximately day 130 of gestation (dG), 71 twin-bearing ewes were placed in the following treatment groups; ewes receiving a positive DCAD TMR (total mixed ration; DCAD of total diet = 281.8 mEq/kg DM; n = 35) and twin-bearing ewes receiving a negative DCAD TMR (DCAD of total diet = -89.0 mEq/kg DM; n = 36). Urine and blood were sampled on dG 130, 140, and 145, and blood was also sampled at the onset of parturition and 4 h postpartum. Urine was analyzed for pH and blood was analyzed for metabolites, mineral concentration, and acid-base balance. Lambs' liveweight, rectal temperature, blood glucose and lactate, and body morphology were measured. Serum phosphate concentrations at dG 145 were significantly lower for negative DCAD ewes compared with positive DCAD ewes (1.9 ± 0.1 vs. 2.1 ± 0.1 mmol/L, P = 0.047). Ionized calcium (P = 0.09) and serum magnesium (P = 0.09) prepartum were marginally greater in the negative DCAD ewes (1.35 ± 0.06 and 1.06 ± 0.03 mmol/L, respectively) compared with the positive DCAD ewes (1.18 ± 0.08 and 0.98 ± 0.04 mmol/L, respectively). Urine pH was lower in the negative DCAD ewes compared with positive DCAD ewes at both dG 140 (7.38 ± 0.17 vs. and 8.10 ± 0.19. P = 0.01) and dG 145 (and 7.20 ± 0.19 vs. 8.25. P < 0.01). The birth interval between the first the second-born lamb was shorter in the negative DCAD ewes compared with the positive DCAD ewes (P = 0.02), but no differences in lamb survival or lamb viability (P > 0.05) were seen. The negative DCAD diet reduced parturition duration, most likely due to the marginally greater ionized calcium and magnesium concentrations. Despite this improvement, the negative DCAD ewes did not reach urinary acidification, indicating that the marginally significant greater ionized calcium and serum magnesium concentrations were due to the magnesium in the diets and not metabolic acidosis. Further research testing a negative DCAD diet that can achieve the target urine pH is required to determine whether this diet can decrease parturition duration and improve lamb viability.

Supplementation of Prenatal Vitamin D to Prevent Children's Stunting: A Literature Review

Background

Stunting is a common nutritional problem in children. Many risk factors contributing to stunting are identified in the literature. Vitamin D supplementation during pregnancy is useful for preventing impairment of fetal bone growth in the womb. However, lack of review in exploring supplementation of prenatal vitamin D is related to stunting in children.

Purpose

This study aims to identify the effectiveness of prenatal vitamin D supplementation in preventing stunting.

Methods

A literature review was conducted using PubMed, CINAHL, ScienceDirect, and Cochrane Library. Inclusion criteria were a randomized controlled trial study, published between 2011-2023, a full-text article for pregnant women and an independent variable supplement vitamin D to prevent children's stunting. The keywords used in English were "children OR child" AND "pregnant women" AND "preventive stunting" AND "vitamin D". Study quality was assessed using the Joanna Briggs Institute (JBI) appraisal tool.

Results

From the results of the study selection of 511 articles, 11 articles met the inclusion and eligibility criteria for study analysis. Four studies indicated that the administration of vitamin D did not influence the length of the neonate's body or the Length for Age Z-Score (LAZ), used as an indicator of stunting. However, seven articles demonstrated that providing vitamin D supplements to pregnant women impacted various aspects of anthropometry, including the length of the neonate's body. Our findings show that the dosage used of vitamin D in pregnancy varied between 1400-60,000 per week. Overall, results of this study analysis show that the intervention of prenatal vitamin D supplementation has an impact on the prevention of stunting.

Conclusion

This literature review highlighted the benefits of maternal vitamin D during pregnancy and for the children's growth. Prenatal vitamin D supplementation is needed to prevent stunting.

Relationship of parathyroid hormone-related protein and neonatal mineral metabolism in dairy cow placentas

Parathyroid hormone-related protein (PTHrP) plays essential roles in placental calcium (Ca) transport, and it has been speculated that PTHrP in the placenta is regulated by calcium-sensing receptors (CaSR). This study clarified the relationship between PTHrP in the placenta of dairy cows and minerals in the fetal blood. Blood samples were obtained from 21 Holstein cows and 17 neonatal calves as well as 12 umbilical veins and arteries during cesarean section. After fetus removal, 13 caruncles and cotyledons were obtained. Concentrations of plasma PTHrP and serum minerals were measured. Real-time polymerase chain reaction (RT-qPCR) analyzed the gene expression of PTHrP and CaSR in the placenta. As a result, serum Ca and inorganic phosphorus concentrations in the neonate, umbilical vein, and artery were significantly higher than in the mother. Additionally, plasma PTHrP was detected in the bovine neonatal jugular vein, umbilical artery, and vein. PTHrP gene expression was significantly higher in the caruncles than in cotyledons; however, CaSR gene expression was higher in the cotyledons than in caruncles. These findings suggest that the PTHrP obtained from the placenta influences Ca homeostasis in the bovine fetus.

Effect of maternal vitamin D status on risk of adverse birth outcomes: a systematic review and dose-response meta-analysis of observational studies

PURPOSE

Accumulating evidence suggests that vitamin D deficiency increases the risk of adverse perinatal outcomes. However, the dose-response relationship between maternal vitamin D status and adverse birth outcomes remains unclear. Focusing on prospective observational studies, we aimed to explore the dose-response relationship of vitamin D status with the risk of low birth weight (LBW), macrosomia (MA), preterm birth (PTB), small for gestational age (SGA), and intrauterine growth restriction (IUGR).

METHODS

Databases including PubMed, Embase, Scopus, and Web of Science were used up to 19 January 2021 to search for observational studies that fulfilled criteria as follows: cohort studies, case-cohort studies, or nested case-control studies. Random-effects models were used to pool relative risks (RRs) and 95% confidence intervals (CIs) in the observational studies.

RESULTS

A total of 72 publications were included in this systematic review and 71 in the meta-analysis. Maternal 25-hydroxyvitamin D (25(OH)D) concentrations were inversely associated with the risk of LBW (RR: 0.65; 95% CI 0.48-0.86), PTB (RR: 0.67; 95% CI 0.57-0.79), and SGA (RR: 0.61; 95% CI 0.49-0.76) in the highest versus lowest meta-analysis, but not associated with MA and IUGR. Linear dose-response analysis showed that each 25 nmol/L increase in 25(OH)D was associated with a 6% and 10% reduction in the risk of PTB (RR: 0.94; 95% CI 0.90-0.98) and SGA (RR: 0.90; 95% CI 0.84-0.97), respectively.

CONCLUSION

Our study suggests that a sufficient vitamin D status during pregnancy is protective against the risk of LBW, PTB, and SGA.

Level of adherence to vitamin D supplementation guidelines in an antenatal centre in Birmingham, UK, and its effect on biochemical and obstetrical outcomes: a single-centre cross-sectional study

OBJECTIVES

A third of pregnant women in the UK are vitamin D deficient, which may confer deleterious consequences, including an increased risk of pre-eclampsia, gestational diabetes mellitus and intrauterine growth restriction. This study aims to determine the proportion of women that met National Institute for Health and Care Excellence (NICE) standards for vitamin D supplementation in pregnancy and compare biochemical and obstetrical outcomes according to supplementation status.

DESIGN AND SETTING

This is a single-centre cross-sectional study in an antenatal centre in Birmingham, UK. Participants received a questionnaire regarding their experiences with vitamin D supplementation during their pregnancy with their general practitioner. Serum 25-hydroxyvitamin D and bone profile results were obtained during the same appointment and obstetrical outcomes were collected retrospectively once participants had delivered.

RESULTS

41.8% of participants (n=61) received written and/or verbal advice about supplementation, (NICE standards=100%). 72.6% (n=106) had one or more risk factors for vitamin D deficiency, of which 38.7% (n=41, NICE standards=100%) were asked about supplementation. Among those asked, 85.4% (n=41, NICE standards=100%) received the correct dosage. Compared with the supplementation group, the non-supplementation group had offspring that were 1.40 cm (95% CI 0.01 to 2.80, p=0.04) longer at birth; which was significant after adjusting for confounding factors. No significant differences in any biochemical parameters were observed between supplementation categories (p>0.05).

CONCLUSIONS

Adherence to NICE standards was suboptimal. This may be attributed to insufficient training for general practitioners on the importance of supplementation, causing them to underestimate the consequences of gestational vitamin D deficiency. Recommendations include implementing a mandatory screening tool to identify 'at-risk' women and providing more clinician training to ensure that supplementation during pregnancy is standard of care.

Hormonal regulation of biomineralization

Biomineralization is the process by which organisms produce mineralized tissues. This crucial process makes possible the rigidity and flexibility that the skeleton needs for ambulation and protection of vital organs, and the hardness that teeth require to tear and grind food. The skeleton also serves as a source of mineral in times of short supply, and the intestines absorb and the kidneys reclaim or excrete minerals as needed. This Review focuses on physiological and pathological aspects of the hormonal regulation of biomineralization. We discuss the roles of calcium and inorganic phosphate, dietary intake of minerals and the delicate balance between activators and inhibitors of mineralization. We also highlight the importance of tight regulation of serum concentrations of calcium and phosphate, and the major regulators of biomineralization: parathyroid hormone (PTH), the vitamin D system, vitamin K, fibroblast growth factor 23 (FGF23) and phosphatase enzymes. Finally, we summarize how developmental stresses in the fetus and neonate, and in the mother during pregnancy and lactation, invoke alternative hormonal regulatory pathways to control mineral delivery, skeletal metabolism and biomineralization.

Effect of High-Dose vs Standard-Dose Vitamin D Supplementation in Pregnancy on Bone Mineralization in Offspring Until Age 6 Years: A Prespecified Secondary Analysis of a Double-Blinded, Randomized Clinical Trial

IMPORTANCE

Studies suggest an association between maternal vitamin D status during pregnancy and offspring anthropometry and bone mineralization, but investigations are few and with mixed results.

OBJECTIVE

To investigate the effect of a high dose vs standard dose of vitamin D supplementation in pregnancy on anthropometric and bone outcomes until age 6 years in the offspring.

DESIGN, SETTING, AND PARTICIPANTS

A prespecified analysis of a double-blinded, randomized clinical trial in the Copenhagen Prospective Studies on Asthma in Childhood 2010 mother-child cohort that included 623 pregnant mothers and their 584 children. Data were analyzed between January 2019 and September 2019.

INTERVENTIONS

Vitamin D supplementation of 2800 IU/d (high-dose) vs 400 IU/d (standard-dose) from pregnancy week 24 until 1 week after birth.

MAIN OUTCOMES AND MEASURES

Longitudinal anthropometry assessments including length/height, weight, and body mass index until age 6 years and bone mineral content (BMC) and bone mineral density (BMD) at age 3 years and 6 years from dual-energy radiography absorptiometry scans.

RESULTS

At age 6 years, 517 children (89%) completed the clinical follow-up. All participants were Danish and white; 261 were boys and 256 were girls. A mixed-effects model analysis of dual-energy radiography absorptiometry scan outcomes from ages 3 years and 6 years showed that children in the vitamin D vs placebo group had higher whole-body BMC: mean difference adjusted (aMD) for age, sex, height, and weight was 11.5 g (95% CI, 2.3-20.7; P = .01); higher whole-body-less-head BMC aMD was 7.5 g (95% CI, 1.5-13.5; P = .01); and higher head BMD aMD was 0.023 g/cm2 (95% CI, 0.003-0.004; P = .03). The largest effect was in children from vitamin D-insufficient mothers (<30 ng/mL; to convert to nanomoles per liter, multiply by 2.496) and among winter births. In a post hoc analysis, we found borderline lower incidence of fractures in the vitamin D group (n = 23 vs n = 36; incidence rate ratio, 0.62 [95% CI, 0.37-1.05]; P = .08), but no differences in any anthropometric outcomes. Adjustment for a concomitant ω-3 polyunsaturated fatty acids intervention did not change the results.

CONCLUSIONS AND RELEVANCE

High-dose vitamin D supplementation in pregnancy improved offspring bone mineralization through age 6 years compared with the standard dose, suggesting an increased recommended gestational intake, which may influence peak bone mass, fracture risk, and risk of osteoporosis later in life. We found no supplementation effect on anthropometric outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00856947.

Approach to patients with hypophosphataemia

Phosphate metabolism is an evolving area of basic and clinical research. In the past 15 years, knowledge on disturbances of phosphate homoeostasis has expanded, as has the discovery of new targeted therapies. Hypophosphataemia might be the biochemical finding in several diseases, and its clinical evaluation should initially focus on the assessment of pathophysiological mechanisms leading to low serum phosphate concentrations. Clinical consequences of hypophosphataemia can involve multiple organ systems and vary depending on several factors, the most important being the underlying disorder. This Review focuses on the approach to patients with hypophosphataemia and how underlying pathophysiological mechanisms should be understood in the evaluation of differential diagnosis. We define an algorithm for the assessment of hypophosphataemia and review the most up-to-date literature on specific therapies. Continuous research in this area will result in a better understanding and management of patients with hypophosphataemia.

Mineral and bone physiology in the foetus, preterm and full-term neonates

Mother is the major source of minerals in foetal life with placenta actively transporting against a concentration and electrochemical gradient. The foetal serum mineral concentration is thereby higher as compared to maternal values, which possibly help in its rapid accretion in developing bones and for counteracting postnatal fall in calcium levels at birth. Parathyroid hormone related peptide (PTHrP) and parathyroid hormone (PTH) play a major role in mineral physiology during foetal life with hormones like calcitriol, calcitonin, FGF-23 and sex steroids having minimal role. PTHrP and PTH also play a major role in endochondral bone formation and mineralization of skeleton. At the birth, as the cord is clamped, there is loss of active transport of minerals through placenta and the neonate has to rely on enteral intake of minerals to meet the demands of growing bones and metabolisms. The calcium levels fall after birth, reaching a nadir at 24-48 h and gradually rise to adult values over several days, probably resulting from a fall in PTHrP levels and hyporesponsiveness of parathyroid glands. As PTH and calcitriol levels increase postnatally, there is a rise in calcium levels with maturation in functioning of kidneys and intestines. However, there may be significant delay in intestinal maturation in preterm infants along with an increased demand for mineral accretion, which predispose them to osteopenia of prematurity.

Post-natal bone physiology

Post-natal bone development is characterized by substantial longitudinal bone growth and changes in skeletal size and shape. Bone is in a dynamic process of continuous remodeling which helps to regulate calcium homeostasis, repair micro-damage to bones from everyday stress, and to shape the skeleton during growth. Bone growth is regulated by systemic hormones and locally generated factors. Understanding their mechanisms of action enables us to obtain a better appreciation of the cellular and molecular basis of bone remodeling and could therefore be valuable in approaches to new therapies. This article will review molecular and cellular control of skeletal growth in the post-natal period, the physiology of each bone cell with their systemic and local regulators, as well as the physiology of bone remodeling.

Higher serum alkaline phosphatase activity in infants born to vitamin D-deficient mothers

Our research shows that the newborns of vitamin D-deficient mothers have higher serum alkaline phosphatase (ALP) activity compared with those of vitamin D-non-deficient mothers, which is likely related to increased bone turnover rather than just being a marker for bone formation. This has a potential negative impact on fetal bone development and subsequent skeletal growth.

PURPOSE/INTRODUCTION

Low maternal serum 25-hydroxy vitamin D (25(OH)D) level during pregnancy contributes to vitamin D deficiency in infants at birth, which is associated with multiple potential adverse effects on fetal skeletal mineralization and growth. We studied the relationship between maternal 25(OH)D level and newborn serum alkaline phosphatase activity (ALP) at term.

METHODS

In this prospective cross-sectional hospital-based study, venous blood samples of healthy pregnant mothers were drawn to measure 25(OH)D levels within 6 h of delivery. Cord blood samples were examined for calcium, phosphorus levels, and ALP activity immediately after birth. In addition, we also recorded the newborns' anthropometric measurements.

RESULTS

Seventy-two percent (n = 108/150) of mothers in our study were vitamin D-deficient (serum 25(OH)2D < 25 nmol/l). In a multivariate logistic regression model, young maternal age (odds ratio (OR) = 0.94, 95% CI 0.88-0.99, p = 0.04) and increased weight (OR = 1.03, 95% CI 1.01-1.07, p = 0.02) as well as decreased milk intake (OR = 0.31, 95% CI 0.13-0.74, p = 0.009) were all significantly associated with maternal vitamin D deficiency. ALP activity was significantly higher in newborns of vitamin D-deficient compared with vitamin D-non-deficient mothers (median = 176 (IQR = 139-221) and 156 (IQR = 132-182), respectively, p = 0.04). A significant inverse correlation (Pearson's coefficient = - 0.18, p = 0.03) was observed between maternal 25(OH)D levels and babies' ALP activities. This association persisted in a multivariate logistic regression model (OR = 3.46, 95% CI 1.18-10.18, p = 0.024).

CONCLUSIONS

Our findings indicate that newborns of vitamin D-deficient mothers have higher serum ALP activity than those of non-deficient mothers, which might be related to increased bone turnover rather than just being a marker for bone formation. This could have a potential negative impact on fetal bone development and subsequent skeletal growth.

Effects of Vitamin D Supplementation During Pregnancy on Birth Size: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

During pregnancy, vitamin D supplementation may be a feasible strategy to help prevent low birthweight (LBW) and small for gestational age (SGA) births. However, evidence from randomized controlled trials (RCTs) is inconclusive, probably due to heterogeneity in study design and type of intervention. A systematic literature search in the PubMed-Medline, EMBASE, and Cochrane Central Register of Controlled Trials databases was carried out to evaluate the effects of oral vitamin D supplementation during pregnancy on birthweight, birth length, head circumference, LBW, and SGA. The fixed-effects or random-effects models were used to calculate mean difference (MD), risk ratio (RR), and 95% Confidence Interval (CI). On a total of 13 RCTs, maternal vitamin D supplementation had a positive effect on birthweight (12 RCTs; MD = 103.17 g, 95% CI 62.29⁻144.04 g), length (6 RCTs; MD = 0.22 cm, 95% CI 0.11⁻0.33 cm), and head circumference (6 RCTs; MD:0.19 cm, 95% CI 0.13⁻0.24 cm). In line with these findings, we also demonstrated that maternal vitamin D supplementation reduced the risk of LBW (3 RCTs; RR = 0.40, 95% CI 0.22⁻0.74) and SGA (5 RCTS; RR = 0.69, 95% CI 0.51⁻0.92). The present systematic review and meta-analysis confirmed the well-established effect of maternal vitamin D supplementation on birth size. However, further research is required to better define risks and benefits associated with such interventions and the potential implications for public health.

Impact of vitamin D on pregnancy-related disorders and on offspring outcome

Observational studies from all over the world continue to find high prevalence rates of vitamin D insufficiency and deficiency in many populations, including pregnant women. Beyond its classical function as a regulator of calcium and phosphate metabolism, vitamin D elicits numerous effects in the human body. Current evidence highlights a vital role of vitamin D in mammalian gestation. During pregnancy, adaptations in maternal vitamin D metabolism lead to a physiologic increase of vitamin D levels, mainly because of an increased renal production, although other potential sources like the placenta are being discussed. A sufficient supply of mother and child with calcium and vitamin D during pregnancy ensures a healthy bone development of the fetus, whereas lack of either of these nutrients can lead to the development of rickets in the child. Moreover, vitamin D insufficiency during pregnancy has consistently been associated with adverse maternal and neonatal pregnancy outcomes. In multitudinous studies, low maternal vitamin D status was associated with a higher risk for preeclampsia, gestational diabetes mellitus and other gestational diseases. Likewise, several negative consequences for the fetus have been reported, including fetal growth restriction, increased risk of preterm birth and a changed susceptibility for later-life diseases. However, study results are diverging and causality has not been proven so far. Meta-analyses on the relationship between maternal vitamin D status and pregnancy outcomes revealed a wide heterogeneity of studied populations and the applied methodology in vitamin D assessment. Until today, clinical guidelines for supplementation cannot be based on high-quality evidence and it is not clear if the required intake for pregnant women differs from non-pregnant women. Long-term safety data of vitamin D supplementation in pregnant women has not been established and overdosing of vitamin D might have unfavorable effects, especially in mothers and newborns with mutations of genes involved in vitamin D metabolism. Reliable data from large observational and interventional randomized control trials are urgently needed as a basis for any detailed and safe recommendations for supplementation in the general population and, most importantly, in pregnant women. This is of utmost importance, as ensuring a sufficient vitamin D-supply of mother and child implies a great potential for the prevention of birth complications and development of diseases.

Sexual Dimorphism and the Origins of Human Spinal Health

Recent observations indicate that the cross-sectional area (CSA) of vertebral bodies is on average 10% smaller in healthy newborn girls than in newborn boys, a striking difference that increases during infancy and puberty and is greatest by the time of sexual and skeletal maturity. The smaller CSA of female vertebrae is associated with greater spinal flexibility and could represent the human adaptation to fetal load in bipedal posture. Unfortunately, it also imparts a mechanical disadvantage that increases stress within the vertebrae for all physical activities. This review summarizes the potential endocrine, genetic, and environmental determinants of vertebral cross-sectional growth and current knowledge of the association between the small female vertebrae and greater risk for a broad array of spinal conditions across the lifespan.

Mineral Homeostasis and Effects on Bone Mineralization in the Preterm Neonate

Most bone formation and mineralization occurs late in gestation. Accretion of adequate minerals is a key element of this process and is often interrupted through preterm birth. In utero, mineral transport is accomplished via active transport across the placenta and does not require fetal hormone input. Postnatal mineral homeostasis requires a balance of actions of parathyroid hormone, calcitonin, and vitamin D on target organs. Preterm birth, asphyxia, acidosis, and prolonged parenteral nutrition increase the risk of mineral imbalance and metabolic bone disease (MBD). Aggressive postnatal nutrition is key to preventing and treating MBD in preterm infants.

Is dietary macronutrient composition during pregnancy associated with offspring birth weight? An observational study

There is lack of evidence on the differential impact of maternal macronutrient consumption: carbohydrates (CHO), fats and protein on birth weight. We investigated the association between maternal dietary macronutrient intakes and their sub-components such as saccharides and fatty acids and birth weight. This analyses included 1,196 women with singleton pregnancies who were part of the CAffeine and REproductive health study in Leeds, UK between 2003 and 2006. Women were interviewed in each trimester. Dietary information was collected twice using a 24-h dietary recall about 8–12 weeks and 13–27 weeks of gestation. Multiple linear regression models adjusted for alcohol and smoking in trimester 1, showed that each additional 10 g/d CHO consumption was associated with an increase of 4 g (95 % CI 1, 7;P=0·003) in birth weight. Conversely, an additional 10 g/d fat intake was associated with a lower birth weight of 8 g (95 % CI 0, 16;P=0·04) when we accounted for energy contributing macronutrients in each model, and maternal height, weight, parity, ethnicity, gestational age at delivery and sex of the baby. There was no evidence of an association between protein intake and birth weight. Maternal diet in trimester 2 suggested that higher intakes of glucose (10 g/d) and lactose (1 g/d) were both associated with higher birth weight of 52 g (95 % CI 4, 100;P=0·03) and 5 g (95 % CI 2, 7;P<0·001) respectively. These results show that dietary macronutrient composition during pregnancy is associated with birth weight outcomes. An appropriately balanced intake of dietary CHO and fat during pregnancy could support optimum birth weight.

Serum Magnesium Levels in Preterm Infants Are Higher Than Adult Levels: A Systematic Literature Review and Meta-Analysis

Magnesium (Mg) is an essential mineral in the body, impacting the synthesis of biomacromolecules, bone matrix development, energy production, as well as heart, nerve, and muscle function. Although the importance of Mg is evident, reference values for serum Mg (sMg) in pediatric patients (more specifically, in neonates) are not well established. This systematic literature review and meta-analysis (using 47 eligible studies) aims to quantify normal and tolerable ranges of sMg concentrations during the neonatal period and to highlight the factors influencing Mg levels and the importance of regulating sMg levels during pregnancy and birth. In newborns without Mg supplementation during pregnancy, magnesium levels at birth (0.76 (95% CI: 0.52, 0.99) mmol/L) were similar to that of mothers during pregnancy (0.74 (95% CI: 0.43, 1.04) mmol/L), but increased during the first week of life (0.91 (95% CI: 0.55, 1.26) mmol/L) before returning to adult levels. This pattern was also seen in newborns with Mg supplementation during pregnancy, where the average was 1.29 (95% CI: 0.50, 2.08) mmol/L at birth and 1.44 (95% CI: 0.61, 2.27) mmol/L during the first week of life. Factors influencing these levels include prenatal Mg supplementation, gestational age, birth weight, renal maturity/function, and postnatal Mg intake. Elevated Mg levels (>2.5 mmol/L) have been associated with an increased risk of mortality, admission into intensive care, hypotonia, hypotension, and respiratory depression but sMg concentrations up to 2.0 mmol/L appear to be well tolerated in neonates, requiring adequate survey and minimal intervention.

Two cases of humoral hypercalcemia of malignancy complicating infantile fibrosarcoma

We report two infants with infantile fibrosarcoma (IFS) complicated by severe hypercalcemia. Assessment demonstrated suppressed parathyroid hormone and 1,25-dihydroxyvitamin D levels with elevated circulating levels of parathyroid hormone related protein, indicating the diagnosis of humoral hypercalcemia of malignancy (HHM). HHM is a paraneoplastic syndrome rarely associated with pediatric malignancies. Hypercalcemia manifested clinically with neurologic symptoms and soft tissue calcium deposition and required aggressive management with intravenous fluids, diuretics, and supplemental electrolytes. Following treatment with neoadjuvant chemotherapy, serum calcium levels precipitously declined requiring calcium repletion. These cases highlight the improvement of hypercalcemia secondary to HHM following chemotherapy.

Vitamin D in pregnancy: current perspectives and future directions

As neonatal vitamin D status is determined by circulating maternal 25-hydroxyvitamin D [25(OH)D] concentrations, prevention of maternal vitamin D deficiency during pregnancy is essential for the avoidance of neonatal deficiency. However, a high prevalence of vitamin D deficiency has been extensively reported among gravidae and neonates from ethnic minorities and white populations resident at high latitude. Currently, regulatory authorities recommend vitamin D intakes for pregnant women that are similar to non-pregnant adults of the same age, at 10-15 µg/day (400-600 IU), to meet 25(OH)D thresholds of 25-50 nmol/liter. The lack of pregnancy-specific dietary recommendations is due to inadequate data indicating whether nutritional requirements for vitamin D during pregnancy differ from the non-pregnant state. In addition, there are few dose-response studies to determine the maternal 25(OH)D response to vitamin D intake throughout pregnancy at high latitude. These data are also required to determine vitamin D requirements during pregnancy for prevention of neonatal deficiency, an outcome which is likely to require a higher maternal 25(OH)D concentration than prevention of maternal deficiency only. With regard to the impact of vitamin D on perinatal health outcomes, which could guide pregnancy-specific 25(OH)D thresholds, dietary intervention studies to date have been inconsistent and recent systematic reviews have highlighted issues of low quality and a high risk of bias as drawbacks in the trial evidence to date. Many observational studies have been hampered by a reliance on retrospective data, unclear reporting, suboptimal clinical phenotyping and incomplete subject characterization. Current investigations of vitamin D metabolism during pregnancy have potentially exciting implications for clinical research. This paper provides an update of current dietary recommendations for vitamin D in pregnant women and a synopsis of the evidence relating vitamin D status with maternal and infant health.

Low-dose developmental exposure to bisphenol A alters the femoral bone geometry in wistar rats

BACKGROUND

Bisphenol A (BPA) is a chemical produced in large volumes for use in manufacturing of consumer products and industrial applications, and an endocrine disruptor known to affect several hormonal systems. Bone produces hormones and is additionally a sensitive hormone target tissue, and is thus potentially sensitive to low doses of endocrine disruptors such as BPA, especially during development.

METHODS

110 pregnant Wistar rats were gavaged with 0; 25 μg; 250 μg; 5000 μg or 50,000 μg BPA/kg bodyweight (bw)/day from gestational day 7 until weaning at postnatal day 22. The three-month-old offspring were sacrificed and right femurs collected for length measurements, geometrical measurements by peripheral quantitative computed tomography (pQCT), as well as for analyses of biomechanical properties using the three-point-bending method.

RESULTS

The femur was elongated in female offspring of dams exposed to 25 or 5000 μg BPA/kg bw/day (1.8% and 2.1%, respectively), and increased cortical thickness (4.7%) was observed in male offspring of dams exposed to 25 μg BPA/kg bw/day, compared to controls (p < 0.005). The biomechanical properties of the bone were not significantly altered.

CONCLUSIONS

In utero and lactational exposure to the lowest BPA dose used in this study altered femoral geometry in both male and female offspring. This was observed at 25 μg BPA/kg bw/day, a dose lower than the Human Equivalent Dose (HED) applied by EFSA to set a temporary TDI (609 μg BPA/kg bw/day), and far lower than the No-Observed-Adverse-Effect-Level (NOAEL) (5000 μg BPA/kg bw/day) on which the US FDA TDI is based.

Fetal Bone Formation Is Decreased from Middle Pregnancy to Birth

Fetal bone development is a complex process that is regulated and maintained by minerals, hormones, and growth factors delivered from the mother via the placenta. Various biochemical markers of fetal bone development have been identified. However, many aspects of this process remain unclear. The aim of the study was to measure the activities of serum tartrate-resistant acid phosphatase type 5b (TRACP 5b) as a bone resorption marker and bone alkaline phosphatase (BAP) as a bone formation marker in preterm and term neonates, and to investigate fetal bone development in middle and late pregnancy. The study included 111 neonates (87 preterm and 24 term) born at Dokkyo Medical University Hospital. Neonates with illnesses and maternal diseases were excluded. Serum samples were collected within 3 hours after birth and stored at -80°C. Univariate and multivariate linear regression analyses were performed. The 111 neonates (median birth weight, 1,510 g) were born at a median of 31.3 weeks of gestation, and had TRACP 5b and BAP activities of 10.9 ± 4.0 U/L and 127.5 ± 49.2 U/L, respectively. TRACP 5b activity showed a tendency to be higher in term neonates, while BAP activity tended to be lower in term neonates. Importantly, TRACP 5b activity was positively correlated with gestational age and birth weight, and BAP activity was negatively correlated with gestational age, rate of born small-for-gestational-age neonates, and birth weight. These results suggest that bone formation during fetal growth is gradually decreased from middle pregnancy to birth, whereas bone resorption is gradually increased.

Potential impact of maternal vitamin D status on obstetric well-being

Despite its discovery 100 years ago, vitamin D (VD) has emerged as one of the most controversial nutrients and prohormones of the 21st century. In the past few years, a growing interest in VD has been observed in the biomedical literature due to evidences demonstrating a relevant relationship not only between regulation of calcium and phosphorus homeostasis, but also multiple disease states and low VD status in the population. Indeed, several studies carried out to decipher its role in the body in almost every cell, tissue, and different organs. Recent findings suggested a significant implication of VD in different physiologic processes , such as vascular health, immune function, metabolism, and placental function. In the attempt to focus the attention on effect of VD on female reproductive health, there has been a paucity of data from randomized controlled trials to establish clear beneficial. Human and animal data suggest that low VD status is associated with impaired fertility, endometriosis, and polycystic ovary syndrome. Findings from observational studies show higher rates of preeclampsia, gestational diabetes, preterm birth, and bacterial vaginosis in women with low VD levels. By recent evidences, this review explored the association between maternal VD status and selected effects on maternal, perinatal, and infant health, and the impact of VD supplementation during pregnancy on obstetric well-being.

Complications of vitamin D deficiency from the foetus to the infant: One cause, one prevention, but who's responsibility?

Calcium and phosphorus represent building material for bones. The supplier of these bone minerals is the hormone calcitriol, which originates from vitamin D, itself made by sunshine in human skin. Requirement for bone minerals is highest during phases of rapid growth, and no one grows faster than the foetus and the infant, making them particularly vulnerable. Deprivation of calcium, whether through low calcium intake or low vitamin D, leads to serious health consequences throughout life, such as hypocalcaemic seizures, dilated cardiomyopathy, skeletal myopathy, congenital and infantile rickets, and osteomalacia. These 5 conditions are often summarised as 'symptomatic vitamin D deficiency', are fully reversible but also fully preventable. However, the increasing prevalence of rickets and osteomalacia, and the deaths from hypocalcaemic cardiomyopathy, demand action from global health care providers. Clarification of medical and parental responsibilities is a prerequisite to deliver successful prevention programmes. The foetus and infant have the human right to be protected against harm, and vitamin D supplementation has the same public health priority as vaccinations.

A review of the impact of dietary intakes in human pregnancy on infant birthweight

Studies assessing maternal dietary intakes and the relationship with birthweight are inconsistent, thus attempting to draw inferences on the role of maternal nutrition in determining the fetal growth trajectory is difficult. The aim of this review is to provide updated evidence from epidemiological and randomized controlled trials on the impact of dietary and supplemental intakes of omega-3 long-chain polyunsaturated fatty acids, zinc, folate, iron, calcium, and vitamin D, as well as dietary patterns, on infant birthweight. A comprehensive review of the literature was undertaken via the electronic databases Pubmed, Cochrane Library, and Medline. Included articles were those published in English, in scholarly journals, and which provided information about diet and nutrition during pregnancy and infant birthweight. There is insufficient evidence for omega-3 fatty acid supplements’ ability to reduce risk of low birthweight (LBW), and more robust evidence from studies supplementing with zinc, calcium, and/or vitamin D needs to be established. Iron supplementation appears to increase birthweight, particularly when there are increases in maternal hemoglobin concentrations in the third trimester. There is limited evidence supporting the use of folic acid supplements to reduce the risk for LBW; however, supplementation may increase birthweight by ~130 g. Consumption of whole foods such as fruit, vegetables, low-fat dairy, and lean meats throughout pregnancy appears beneficial for appropriate birthweight. Intervention studies with an understanding of optimal dietary patterns may provide promising results for both maternal and perinatal health. Outcomes from these studies will help determine what sort of dietary advice could be promoted to women during pregnancy in order to promote the best health for themselves and their baby.