Cord blood levels of osteopontin as a phenotype marker of gestational age and neonatal morbidities

An expert panel on the adequacy of safety data and physiological roles of dietary bovine osteopontin in infancy

Human milk, due to its unique composition, is the optimal standard for infant nutrition. Osteopontin (OPN) is abundant in human milk but not bovine milk. The addition of bovine milk osteopontin (bmOPN) to formula may replicate OPN's concentration and function in human milk. To address safety concerns, we convened an expert panel to assess the adequacy of safety data and physiological roles of dietary bmOPN in infancy. The exposure of breastfed infants to human milk OPN (hmOPN) has been well-characterized and decreases markedly over the first 6 months of lactation. Dietary bmOPN is resistant to gastric and intestinal digestion, absorbed and cleared from circulation within 8-24 h, and represents a small portion (<5%) of total plasma OPN. Label studies on hmOPN suggest that after 3 h, intact or digested OPN is absorbed into carcass (62%), small intestine (23%), stomach (5%), and small intestinal perfusate (4%), with <2% each found in the cecum, liver, brain, heart, and spleen. Although the results are heterogenous with respect to bmOPN's physiologic impact, no adverse impacts have been reported across growth, gastrointestinal, immune, or brain-related outcomes. Recombinant bovine and human forms demonstrate similar absorption in plasma as bmOPN, as well as effects on cognition and immunity. The panel recommended prioritization of trials measuring a comprehensive set of clinically relevant outcomes on immunity and cognition to confirm the safety of bmOPN over that of further research on its absorption, distribution, metabolism, and excretion. This review offers expert consensus on the adequacy of data available to assess the safety of bmOPN for use in infant formula, aiding evidence-based decisions on the formulation of infant formula.

Association between prenatal socioeconomic disadvantage, adverse birth outcomes, and inflammatory response at birth

Prenatal socioeconomic disadvantage is associated with inflammation in mid- to late-life, yet whether a pro-inflammatory phenotype is present at birth and the role of adverse birth outcomes in this pathway remains unclear. We utilized data on prenatal socioeconomic disadvantage at the individual- (i.e., mother's and father's education level, insurance type, marital status, and Women, Infants, and Children benefit receipt) and census-tract level as well as preterm (< 37 weeks gestation) and small-for-gestational-age (SGA) (i.e., < 10th percentile of sex-specific birth weight for gestational age) birth status, and assessed inflammatory markers (i.e., C-reactive protein, serum amyloid p, haptoglobin, and α-2 macroglobulin) in archived neonatal bloodspots from a Michigan population-based cohort of 1000 neonates. Continuous latent variables measuring individual- and combined individual- and neighborhood-level prenatal socioeconomic disadvantage were constructed and latent profile analysis was used to create a categorical inflammatory response variable (high versus low) based on continuous inflammatory marker levels. Structural equation models were used to estimate the total and direct effect of prenatal socioeconomic disadvantage on the inflammatory response at birth as well as indirect effect via preterm or SGA birth (among term neonates only), adjusting for mother's age, race/ethnicity, body mass index, smoking status, comorbidities, and antibiotic use/infection as well as grandmother's education level. There was a statistically significant total effect of both individual- and combined individual- and neighborhood-level prenatal socioeconomic disadvantage on high inflammatory response among all neonates as well as among term neonates only, and a positive but not statistically significant direct effect in both groups. The indirect effects via preterm and SGA birth were both negative, but not statistically significant. Our findings suggest prenatal socioeconomic disadvantage contributes to elevated neonatal inflammatory response, but via pathways outside of these adverse birth outcomes.

The Association between Hemodynamically Significant Patent Ductus Arteriosus and 25-Hydroxyvitamin D Levels in Preterm Infants ≤32 Weeks Gestational Age

INTRODUCTION

We investigated the relationship between 25-hydroxyvitamin D (25-OHD) levels and the development of hemodynamically significant patent ductus arteriosus (hsPDA) in preterm infants.

METHODS

Newborns having a gestational age (GA) of ≤32 weeks with hsPDA consisted the study group (n = 25, 20%), while newborns ≤32 weeks of GA without PDA/hsPDA were the control group (n = 97, 80%).

RESULTS

The study group had lower GA, birth weight (BW) and 25-OHD levels (p < 0.0001, p = 0.002 and p = 0.003, respectively). After adjusting for the effects of GA, BW and the presence of respiratory distress syndrome, multivariable logistic regression analyses demonstrated that preterm infants with low 25-OHD levels were 6.407 (95% CI: 1.656-24.788, p = 0.007) times more likely to experience hsPDA than preterm infants with normal 25-OHD levels. Every 1 ng/mL increase in 25-OHD levels decreased the probability of hsPDA (OR: 0.894, 95% CI: 0.816-0.98, p = 0.016). Conclusion: Low 25-OHD levels may have a role in the development of hsPDA.

Cord blood adiponectin and leptin are associated with a lower risk of stunting during infancy

Undernutrition is responsible for up to 45% of deaths in children under five, with low- and middle-income countries disproportionately affected. Adipokines are known modulators of metabolism and have been linked to growth rates and neurocognition during infancy. We examined the relationship(s) between cord blood adiponectin and leptin and both longitudinal growth and cognition during the first year of life using generalized estimating equations. Infants were classified as underweight (weight-for-age z-score [WAZ]), stunted (height-for-age z-score [HAZ]) or wasted (weight-for-height z-score [WHZ]) using WHOAnthro software. Cord blood adiponectin and leptin levels were highly correlated (r = 0.35, P < 0.0001) and positively associated with birth WAZ (r = 0.34 and r = 0.45, P < 0.0001, respectively). Adipokines were independently, inversely associated with weight gain. Infants in the highest quintile of adipokine production had a lower risk of being stunted, while neither was associated with lower WAZ or WHZ in final adjusted models. Cognition was not found to be independently related to cord blood leptin or adiponectin. The negative association with adipokines and rate of weight gain during infancy may reflect heightened nutritional status at birth rather than a direct hormonal influence. The relationship between leptin or adiponectin and longitudinal length gains suggests that both adipokines may promote linear growth during infancy.

The Patent Ductus Arteriosus in Extremely Preterm Neonates Is More than a Hemodynamic Challenge: New Molecular Insights

Complications to preterm birth are numerous, including the presence of a patent ductus arteriosus (PDA). The biological understanding of the PDA is sparse and treatment remains controversial. Herein, we speculate whether the PDA is more than a cardiovascular imbalance, and may be a marker in response to immature core molecular and physiological processes driven by biological systems, such as inflammation. To achieve a new biological understanding of the PDA, we performed echocardiography and collected plasma samples on day 3 of life in 53 consecutively born neonates with a gestational age at birth below 28 completed weeks. The proteome of these samples was analyzed by mass spectrometry (nanoLC-MS/MS) and immunoassay of 17 cytokines and chemokines. We found differences in 21 proteins and 8 cytokines between neonates with a large PDA (>1.5 mm) compared to neonates without a PDA. Amongst others, we found increased levels of angiotensinogen, periostin, pro-inflammatory associations, including interleukin (IL)-1β and IL-8, and anti-inflammatory associations, including IL-1RA and IL-10. Levels of complement factors C8 and carboxypeptidases were decreased. Our findings associate the PDA with the renin-angiotensin-aldosterone system and immune- and complement systems, indicating that PDA goes beyond the persistence of a fetal circulatory connection of the great vessels.

Osteopontin and malaria: no direct effect on parasite growth, but correlation with P. falciparum-specific B cells and BAFF in a malaria endemic area

Background

The dysregulation of B cell activation is prevalent during naturally acquired immunity against malaria. Osteopontin (OPN), a protein produced by various cells including B cells, is a phosphorylated glycoprotein that participates in immune regulation and has been suggested to be involved in the immune response against malaria. Here we studied the longitudinal concentrations of OPN in infants and their mothers living in Uganda, and how OPN concentrations correlated with B cell subsets specific for P. falciparum and B cell activating factor (BAFF). We also investigated the direct effect of OPN on P. falciparum in vitro.

Results

The OPN concentration was higher in the infants compared to the mothers, and OPN concentration in infants decreased from birth until 9 months. OPN concentration in infants during 9 months were independent of OPN concentrations in corresponding mothers. OPN concentrations in infants were inversely correlated with total atypical memory B cells (MBCs) as well as P. falciparum-specific atypical MBCs. There was a positive correlation between OPN and BAFF concentrations in both mothers and infants. When OPN was added to P. falciparum cultured in vitro, parasitemia was unaffected regardless of OPN concentration.

Conclusions

The concentrations of OPN in infants were higher and independent of the OPN concentrations in corresponding mothers. In vitro, OPN does not have a direct effect on P. falciparum growth. Our correlation analysis results suggest that OPN could have a role in the B cell immune response and acquisition of natural immunity against malaria.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02368-y.

Quantitative determination of osteopontin in bovine, buffalo, yak, sheep and goat milk by Ultra-high performance liquid chromatography-tandem mass spectrometry and stable isotope dimethyl labeling

Osteopontin (OPN) is a multifunctional protein present in different tissues, body fluids and milk. Different milk has different level of OPN content. To determine the amount of osteopontin in bovine, buffalo, yak, sheep and goat milk, we developed an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method to detect an osteopontin signature peptide. The signature peptides selected by searching Uniprot database for trypsin digested osteopontin. The sample preparation procedure includes trypsin digestion, dimethyl labeling of tryptic peptides, purification and concentration of labeled tryptic peptide with solid phase extraction. The limit of detection and limit of quantification are 0.5 mg L^-1 and 2.0 mg L^-1, respectively. The method has satisfactory analytical performance with a linearity of R² ≥ 0.998, recoveries of 103.7-111.0%, and precision of 1.8-6.2%. It is also validated and successfully applied to quantifying osteopontin content in bovine, buffalo, yak, sheep and goat milk.

Plasma levels of osteopontin from birth to adulthood

AIM

Osteopontin (OPN) has been investigated as a biomarker for cancer and nonmalignant diseases during the last decades. Data about OPN as a potential biomarker in childhood diseases are still sparse, and reference values are not available in children. We aimed to establish reference values for children from birth to young adulthood and evaluate whether there are age-, gender-, and weight-specific differences.

METHOD

Umbilical cord blood and blood plasma samples of 117 children were collected in the Children's Hospital of Saarland University in Homburg/Saar. OPN levels were measured by ELISA, and statistical analysis was performed using SPSS software.

RESULTS

Neonates, infants, toddlers, young children, adolescents, and adults were divided into the following six age groups: newborns (birth), infancy and toddlers (0-24 months), early childhood (3-6 years), middle childhood (7-11 years), adolescence (12-18 years), and adults (> 18 years). Highest blood OPN levels were found in the group of 0-1 years of age. OPN blood levels declined significantly with age (Spearman r = -0.874; P < 0.001).

CONCLUSION

Our work is the first prospective and systematic study analyzing OPN cord blood and blood plasma levels in children of all ages. It is the first study yielding reference values for different age groups from birth to young adulthood. Our data give insight on how OPN in umbilical cord blood and OPN in blood plasma are physiologically influenced during childhood development and growth with high OPN levels after birth and a constant age-related decline until the age of 14, when OPN levels reach similar values to those measured in adults.

Benefits of Lactoferrin, Osteopontin and Milk Fat Globule Membranes for Infants

The provision of essential and non-essential amino acids for breast-fed infants is the major function of milk proteins. In addition, breast-fed infants might benefit from bioactivities of milk proteins, which are exhibited in the intestine during the digestive phase and by absorption of intact proteins or derived peptides. For lactoferrin, osteopontin and milk fat globule membrane proteins/lipids, which have not until recently been included in substantial amounts in infant formulas, in vitro experiments and animal models provide a convincing base of evidence for bioactivities, which contribute to the protection of the infant from pathogens, improve nutrient absorption, support the development of the immune system and provide components for optimal neurodevelopment. Technologies have become available to obtain these compounds from cow´s milk and the bovine compounds also exhibit bioactivities in humans. Randomized clinical trials with experimental infant formulas incorporating lactoferrin, osteopontin, or milk fat globule membranes have already provided some evidence for clinical benefits. This review aims to compare findings from laboratory and animal experiments with outcomes of clinical studies. There is good justification from basic science and there are promising results from clinical studies for beneficial effects of lactoferrin, osteopontin and the milk fat globule membrane complex of proteins and lipids. Further studies should ideally be adequately powered to investigate effects on clinically relevant endpoints in healthy term infants.