Cytokines, Chemokines, and Growth Factors in Banked Human Donor Milk for Preterm Infants

Inflammatory Markers in Mother's Own Milk and Infant Stool of Very Low Birthweight Infants

BACKGROUND

Mother's breastmilk is the gold standard for feeding preterm infants. Preterm delivery may be precipitated by inflammatory maternal states, but little is known about milk cytokine profiles and how they correlate with markers of infant gut inflammation (i.e., stool calprotectin) in this vulnerable population.

RESEARCH AIM

To assess cytokines and inflammatory markers in milk from parents of very preterm infants over time as well as correlations between milk and infant's stool calprotectin.

METHOD

This is a secondary analysis of milk samples collected during OptiMoM, a triple-blind randomized clinical trial of infants born < 1250 g (NCT02137473). Longitudinally collected samples were analyzed for cytokines, choline, and inflammatory markers (C-reactive protein [CRP], IFN-γ, IL-10, IL-1β, IL-1ra, IL-6, IL-8, TNF-α). Infant stools were collected for longitudinal calprotectin analysis. Generalized estimating equations quantified longitudinal profiles of milk markers and stool calprotectin, their associations, and the correlation between free choline and C-reactive protein over follow-up.

RESULT

Participants included 92 parents and infants (median weeks of gestation 27.3, median birth weight 845 g, and prevalence of male infants 45%). In all, 212 milk samples and 94 corresponding stool calprotectin levels were collected 1-11 weeks postpartum. C-reactive protein was present in much higher concentrations than other markers, and was highest in Week 1 postpartum. It decreased over time. IL-8 and free choline also changed over time while other markers did not. There was no correlation between any milk markers and stool calprotectin.

CONCLUSION

Milk from mothers of very preterm infants has detectable inflammatory markers, some of which change over time. Research is needed to determine if infant outcomes are associated with these markers.

Exclusive human milk diet reduces incidence of severe intraventricular hemorrhage in extremely low birth weight infants

OBJECTIVE

Compare the incidence of severe (grade III/IV) intraventricular hemorrhage (IVH) and/or periventricular leukomalacia (PVL) between two groups of ELBW infants based on diet until 34 weeks corrected gestational age (CGA): (1) Exclusive human milk (EHM)-mother's own and/or pasteurized donor human milk, human milk-derived fortifier, and oral care with colostrum/human milk vs. (2) non-EHM-bovine formula or mother's own milk with bovine-derived fortifier.

STUDY DESIGN

Retrospective observational study of two groups of ELBW infants based on diet until 34 weeks CGA.

RESULT

There were n = 306 infants, 127 EHM and 179 non-EHM. Demographics and morbidities were similar except higher antenatal steroids and NEC in EHM group. The rate of severe IVH/PVL was lower in EHM compared to non-EHM group (7 vs. 18%, p < 0.006).

CONCLUSION

EHM diet had an independent neuroprotective effect and was associated with decreased incidence of severe IVH/PVL, supporting the need of EHM in ELBW infants.

Contributors to Dysbiosis in Very-Low-Birth-Weight Infants

The objective of this commentary was to analyze the causes and outcomes of gut microbiome dysbiosis in preterm infants who are born at very low birth weight (VLBW). The intrauterine development of VLBW infants is interrupted abruptly with preterm birth and followed by extrauterine, health-threatening conditions and sequelae. These infants develop intestinal microbial dysbiosis characterized by low diversity, an overall reduction in beneficial and/or commensal bacteria, and enrichment of opportunistic pathogens of the Gammaproteobacteria class. The origin of VLBW infant dysbiosis is not well understood and is likely the result of a combination of immaturity and medical care. We propose that these factors interact to produce inflammation in the gut, which further perpetuates dysbiosis. Understanding the sources of dysbiosis could result in interventions to reduce gut inflammation, decrease enteric pathology, and improve health outcomes for these vulnerable infants.

The data and characteristics of the human milk banks in mainland China

BACKGROUND

Human milk banks (HMB) have been established for over 100 years in North America and Europe. This study aimed to describe and summarize the operation and characteristics of the HMBs in mainland China since the first nonprofit HMB operated in 2013.

METHODS

Operation of HMB in mainland China is based on the standards and guidelines of the Human Milk Banking Association of North America and some countries in Europe and was modified to meet the needs and circumstances in China such as donation only in the local HMB by medical staff. We reviewed the descriptive data of these 14 HMBs and the clinical characteristics of recipients, the eligible milk donors and the donor milk retrospectively.

RESULTS

In mainland China, from March 2013 to December 2016, 14 nonprofit HMBs were developed and operational in public hospitals except one and located in the south, east, north and northwest of mainland China. In total, 2680 eligible donors donated 4608.2 L of breast milk. The mean age of these donors was 29.4 years with 60.6% receiving college education and 90.6% term delivery. A total of 4678 recipients including preterm infants (n = 2990, 63.9%), feeding intolerance (n = 711, 15.2%), maternal illness (n = 345, 7.4%), serious infection (n = 314, 6.7%), necrotising enterocolitis (n = 244, 5.2%), post-surgery (n = 38, 0.8%) and others (n = 36, 0.8%). The rate of discarded raw milk was only 4.4% because of hepatitis B and C or cytomegalovirus positivity.

CONCLUSIONS

HMB has been developing rapidly in mainland China. Donor human milk was used not only for preterm infants but also for other ill children. But the sustainability of milk banking needs proper management and more financial support by relative health authorities and the government.

Donor milk intake and infant growth in a South African neonatal unit: a cohort study

Background

Implications of donor milk feedings on infant growth in resource limited settings remain uncertain. This knowledge gap includes the impact of donor milk availability on infant intake of mother’s own milk. Therefore, this investigation aimed to measure intake and growth in infants receiving donor milk when born to women from resource limited backgrounds with high rates of human immunodeficiency virus (HIV).

Methods

A retrospective cohort study enrolled eligible infants admitted to a South African combined neonatal intensive and secondary high care unit, within a one year admission period during 2015, with signed consent for donor milk feedings. A certified milk bank provided donor milk. Daily nutritional intake during the first month was recorded. Details included proportional intake of donor milk, mother’s own milk and infant formula. The primary outcome of infant growth velocity from day back to birth weight to discharge was calculated when length of stay was ≥14 days. Analyses primarily used T-tests; mixed effects models compared weekly calorie intake.

Results

One hundred five infants with donor milk consent were born at 30.9 ± 3.6 weeks of gestation, weighing 1389 ± 708 g. Forty percent of mothers had HIV. Infant growth velocity did not differ based on percent of feedings as donor milk (≥ 50%: 11.8 ± 4.9 g/kg/d; < 50%: 13.5 ± 5.3 g/kg/d; p = 0.3). Percent of feedings from donor milk was similar based on maternal HIV status (positive: 31 ± 25%; negative: 36 ± 29%; p = 0.4), as was percent of feedings as mother’s milk (positive: 53 ± 35%; negative: 58 ± 30%; p = 0.4). Calorie intake increased markedly during the first two weeks and then plateaued (p < 0.0001).

Conclusions

Donor milk feedings in higher proportions did not further impair growth of infants managed in a South African combined neonatal intensive and secondary high care unit with growth rates already below reference ranges. The provision of donor milk contributed to feedings being composed of primarily human milk during the first month. Increasing early calorie intake may improve infant growth in this center.

Pasteurization Preserves IL-8 in Human Milk

Background: Pasteurized donor human milk is an alternative feeding when mothers' own milk is not available for premature infants. The effects of pasteurization on the host defense properties of human milk are unclear. We investigated the effects of Holder pasteurization on concentrations of anti-inflammatory and pro-inflammatory cytokines in human milk. Objective: To compare concentrations of anti-inflammatory and pro-inflammatory cytokines before and after pasteurization of donor human milk. Study Design: A single milk sample was obtained from each of 24 mothers of premature infants in the neonatal intensive care unit by electric breast pump and was stored at -80°C. At the time of pasteurization, milk samples were thawed and divided into two aliquots. The first aliquot was re-stored at -80°C and the second aliquot was heat-treated at 62.5°C for 30 min and then re-stored at -80°C. At the time of batch cytokine analyses samples were thawed rapidly. Results: Most cytokine concentrations declined following pasteurization. The most prevalent cytokine, IL-8, was preserved (89%) following pasteurization. There were no relationships between gestational age, postnatal age of milk collection, duration of milk storage, and the concentrations cytokines. Conclusion: In contrast to most cytokines after pasteurization, IL-8 is preserved or liberated from another compartment. The maintenance of IL-8 in human milk after pasteurization and the loss of anti-inflammatory cytokines following pasteurization, suggests that the effects of inflammatory activity in pasteurized human milk should be evaluated. These data may account, in part, for the lesser protective effect on the host of pasteurized donor human milk compared with mother's own milk.

High Levels of Chemokine C-C Motif Ligand 20 in Human Milk and Its Production by Oral Keratinocytes

BACKGROUND

Chemokine C-C motif ligand 20 (CCL20) is implicated in the formation and function of mucosal lymphoid tissues. Although CCL20 is secreted by many normal human tissues, no studies have evaluated the presence of CCL20 in human milk or its production by oral keratinocytes stimulated by human milk.

OBJECTIVE

To evaluate the presence of CCL20 in breast milk and verify CCL20 secretion in vitro by oral keratinocytes stimulated with human and bovine milk, as well as its possible association with breast milk lactoferrin levels.

MATERIALS AND METHODS

The levels of CCL20 and lactoferrin were measured by enzyme-linked immunosorbent assay in human milk at three different stages of maturation from 74 healthy breastfeeding mothers. In vitro, oral keratinocytes were stimulated with human and bovine milk, and CCL20 was measured in their supernatant.

RESULTS

High concentrations of CCL20 were detected in the human breast milk samples obtained during the first week (1,777.07 pg/mL) and second week postpartum (1,523.44 pg/mL), with a significantly low concentration in samples at 3-6 weeks postpartum (238.42 pg/mL; p < 0.0001). Human breast milk at different weeks postpartum stimulated higher CCL20 secretion by oral keratinocytes compared with bovine milk (p < 0.05). Such stimulation had no association with breast milk lactoferrin concentration.

CONCLUSION

CCl20 is present at high levels in human milk, predominantly in the first and second week postpartum, but at significantly lower levels at 3-6 weeks postpartum. Human milk is capable of stimulating CCL20 secretion by oral keratinocytes, and this induction had no association with breast milk lactoferrin concentration.

Human Milk-Treatment and Quality of Banked Human Milk

The aim of human milk banks is to deliver safe and high quality donor human milk. Treatment of human milk has to destroy most microorganisms while preserving immunological and nutrient components, which is obtained when using low time low temperature pasteurization. However it destroys bile-simulated lipase, reduces lactoferrin, lysozyme, immunoglobulins, and bactericidal capacity of human milk. New methods are under investigation such as high temperature short time pasteurization, high pressure processing, or ultraviolet irradiation. They have been tested in experimental conditions and there are promising results, but they have to be tested in real conditions in human milk bank.

Maternal Interleukin Genotypes Are Associated With NICU Outcomes Among Low-Birth-Weight Infants

BACKGROUND

Maternal interleukin (IL) single nucleotide polymorphisms (SNPs) are associated with obstetrical outcomes. Conversely, infant SNPs are associated with subsequent neonatal intensive care unit (NICU) outcomes. Little is known about relationships between maternal SNPs and neonatal outcomes.

PURPOSE

To examine the relationships between maternal IL genotypes and neonatal outcomes.

METHODS

An ancillary study was conducted among mothers ( N = 63) who delivered very low-birth-weight infants ( N = 74). Maternal DNA was extracted from breast milk and genotyped. Outcomes included fecal calprotectin, length of stay, scores for neonatal acute physiology with perinatal extension (SNAPPE-II), weight gain, oxygen needs, necrotizing enterocolitis, intraventricular hemorrhage, sepsis, retinopathy of prematurity, blood transfusions, and feeding intolerance. Multivariate analyses examined the relationships between maternal IL SNPs and outcomes, controlling for gestational age and the ratio of maternal milk to total milk.

RESULTS

Absence of a minor allele in 2 IL6 SNPs was associated with fecal calprotectin ( p = .0222, p = .0429), length of stay ( p = .0158), SNAPPE-II ( p = .0497), weight gain ( p = .0272), and days on oxygen ( p = .0316). IL6 genotype GG (rs1800795) was associated with length of stay ( p = .0034) and calprotectin ( p = .0213). Minor-allele absence in 2 IL10 SNPs was associated with days on oxygen ( p = .0320). There were associations between IL10 genotype TT (rs1800871) and calprotectin ( p = .0270) and between IL10 genotypes AA (rs1800872 and rs1800896) and calprotectin ( p = .0158, p = .0045).

CONCLUSION

Maternal IL SNPs are associated with NICU outcomes. A potential clinical application includes an antenatal risk profile to identify neonatal needs.

Effect of Promoter Polymorphisms on Cytokine Concentration in Preterm Breast Milk and Subsequent Infant Outcomes

BACKGROUND

Breast milk concentrations of immune components are variable between women and interleukin (IL) differences may be associated with infant outcomes. Molecular mechanisms for milk variability remain unknown.

OBJECTIVE

The aims were to (1) examine the relationship between maternal IL genotypes and milk concentrations of IL4, IL6, and IL10, (2) describe the trajectories of milk IL change, (3) examine whether maternal IL genotypes predict IL trajectories and/or average weekly IL concentration, and (4) examine if weekly IL levels and/or IL trajectories are associated with infant outcomes.

METHODS

Milk aliquots were collected from each feeding of mother's own milk and pooled weekly. DNA was extracted from 1 sample of each mother's breast milk whey (n = 64), and single nucleotide polymorphisms (SNPs) of IL genes were genotyped. Milk IL concentrations were measured and trajectory analysis examined IL milk change over time. Multivariate breast milk IL concentration analyses controlled for gestational age and prepregnancy body mass index. Multivariate infant outcome (n = 73) analyses controlled for gestational age and the ratio of human milk to total milk.

RESULTS

Trajectory analysis resulted in linear group shapes, with 2 distinct subgroups in IL6 and 3 subgroups in IL4 and IL10. Trajectory groups trended toward significance with calprotectin, intraventricular hemorrhage, and blood transfusions. Multivariate analyses resulted in trending associations between maternal SNPs and subsequent IL6 and IL10 milk levels. There was a trending relationship between IL milk levels and both fecal calprotectin and intraventricular hemorrhage.

CONCLUSION

Maternal IL SNPs may affect IL breast milk levels and IL milk levels may be associated with infant outcomes.

Changes in the Immune Components of Preterm Human Milk and Associations With Maternal and Infant Characteristics

OBJECTIVE

To describe difference in cytokines, chemokines, and growth factors (CCGFs) and secretory immunoglobulin A (sIgA) in the breast milk of mothers who gave birth preterm and maternal or infant characteristics related to these immune components.

DESIGN

A prospective, repeated-measures, one-group design.

SETTING

Data were collected at an 82-bed NICU in West Central Florida.

PARTICIPANTS

Seventy-six very-low-birth-weight infants weighing less than 1,500 g and their mothers.

METHODS

Daily aliquots of breast milk from mothers of preterm infants were collected from the daily infants' feedings and pooled at the end of each week, and CCGFs and sIgA were measured weekly with MagPix multiplexing (Luminex, Austin, TX) and enzyme-linked immunosorbent assay.

RESULTS

The CCGFs showed high individual variability, but the levels of most CCGFs and sIgA fell over time. Immune variables were generally greater in milk from mothers of infants smaller than 1,000 g. The breast milk of mothers of male preterm infants had significantly greater sIgA than the breast milk of mothers of female preterm infants. We found relationships between age, body mass index, parity, sIgA, and some of the CCGFs in the breast milk of women who gave birth preterm.

CONCLUSION

Immune molecules declined in concentration over time in the breast milk of mothers who give birth preterm during the NICU stay, and maternal and infant factors appeared to play some role in the levels of these immune molecules. Further exploration of this relationship is warranted.

Breast Feeding and Melatonin: Implications for Improving Perinatal Health

The biological underpinnings that drive the plethora of breastfeeding benefits over formula-feeding is an area of intense research, given the cognitive and emotional benefits as well as the offsetting of many childhood- and adult-onset medical conditions that breast-feeding provides. In this article, we review the research on the role of melatonin in driving some of these breastfeeding benefits. Melatonin is a powerful antioxidant, anti-inflammatory and antinociceptive as well as optimizing mitochondrial function. Melatonin is produced by the placenta and, upon parturition, maternal melatonin is passed to the infant upon breastfeeding with higher levels in night-time breast milk. As such, some of the benefits of breastfeeding may be mediated by the higher levels of maternal circulating night-time melatonin, allowing for circadian and antioxidant effects, as well as promoting the immune and mitochondrial regulatory aspects of melatonin; these actions may positively modulate infant development. Herein, it is proposed that some of the benefits of breastfeeding may be mediated by melatonin's regulation of the infant's gut microbiota and immune responses. As such, melatonin is likely to contribute to the early developmental processes that affect the susceptibility to a range of adult onset conditions. Early research on animal models has shown promising results for the regulatory role of melatonin.

Longitudinal Study of Cytokine Expression, Lipid Profile and Neuronal Growth Factors in Human Breast Milk from Term and Preterm Deliveries

Breast milk (BM) is considered as a reference for infant nutrition. The role of bioactive components, such as cytokines, hormones, growth factors (GFs) and fatty acids (FAs) is poorly known, but they might be implicated in immune response development. The aim of this study was to identify the lipid profile and the spectrum of cytokines and neuronal GF in BM samples and analyse the influence of gestational age and lactation time on these components. This study used a longitudinal prospective method for the characterization of cytokines, FAs and GFs global profiles in 120 BM samples from 40 healthy mothers (20 preterm and 20 term) collected as colostrum, transitional and mature milk. The cytokines were analysed by protein array (Ray Bio® Human Cytokine Array G6. Ray Biotech, Inc. Norcross, GA, USA) and the FAs were analysed by gas chromatography. The FA profile was similar between the term and the preterm BM samples. Omega-3-α-linoleic and docosahexaenoic acid (DHA) and omega-6-linoleic acid were the most abundant in the term and preterm samples during lactation. Omega-3 ETA and omega-3 EPA we observed exclusively in the preterm samples. The cytokine profile showed a different trend based on gestational age. A significantly higher expression of neurotrophic factors was found in the mature preterm milk samples as compared to the mature term samples. Our study is the first to identify the influence and interactions of perinatal factors on cytokine, GFs and FAs in human milk.

Human milk pasteurization: benefits and risks

PURPOSE OF REVIEW

Recent findings substantiate that the optimal method of nourishing preterm, very low birth weight infants (VLBW, born <1500 g) is through appropriately nutrient-enriched human milk, which is frequently provided as pasteurized donor milk. The availability of donor milk for VLBW infants during initial hospitalization continues to increase with the launch of new milk banks in North America. The majority of North American neonatal ICUs now have written policies governing the provision of donor milk. The purpose of this review is to summarize recent evidence regarding the risks and benefits of pasteurization of human milk and outcomes associated with its provision to VLBW preterm infants.

RECENT FINDINGS

Studies investigating the impact of collection, storage and pasteurization on the bacteriostatic, immunologic and nutritional aspects of human milk continue to be published, generally revealing a partial, but not complete reduction in bioactivity. Risk of contamination of pasteurized donor human milk with pathogenic agents is mitigated through pasteurization. New pasteurization methods aiming to maintain the safety of pooled human milk while better preserving bioactivity are under investigation.

SUMMARY

Provision of a human milk-derived diet to preterm VLBW infants is associated with improved outcomes.