Viruses and Human Milk: Transmission or Protection?

Human milk (HM) is considered the best source of nutrition for infant growth and health. This nourishment is unique and changes constantly during lactation to adapt to the physiological needs of the developing infant. It is also recognized as a potential route of transmission of some viral pathogens although the presence of a virus in HM rarely leads to a disease in an infant. This intriguing paradox can be explained by considering the intrinsic antiviral properties of HM. In this comprehensive and schematically presented review, we have described what viruses have been detected in HM so far and what their potential transmission risk through breastfeeding is. We have provided a description of all the antiviral compounds of HM, along with an analysis of their demonstrated and hypothesized mechanisms of action. Finally, we have also analyzed the impact of HM pasteurization and storage methods on the detection and transmission of viruses, and on the antiviral compounds of HM. We have highlighted that there is currently a deep knowledge on the potential transmission of viral pathogens through breastfeeding and on the antiviral properties of HM. The current evidence suggests that, in most cases, it is unnecessarily to deprive an infant of this high-quality nourishment and that the continuation of breastfeeding is in the best interest of the infant and the mother.

Recommendations for the establishment and operation of a donor human milk bank.

In Europe, an increasing number of human milk banks (HMBs) collect donor human milk to feed preterm infants when their mother's milk is not available or not enough. Moreover, donor milk is a bridge to breastfeeding, with positive clinical and psychological advantages for both mother and infant. Italy, with 41 HMBs actively operating in 2022, has the highest number of HMBs in Europe. The process of human milk donation is complex, so activity of HMBs must be regulated according to well-established rules. The present recommendations have been prepared as a tool to standardize the organization, management, and procedures of HMBs operating in Italy and to determine the minimal essential requirements to establish new HMBs. This article covers all the aspects of human milk donation and human milk banking, including general recommendations, donor recruitment and screening, expression, handling and storage of donor human milk, milk screening, and milk treatment (pasteurization). A pragmatic approach was taken to drafting the recommendations. Items for which there was consensus or robust published evidence on which to base recommendations were included. When there were differences that could not be resolved by reference to published research, a statement of explanation based on the expert opinion of the authors (all members of the Italian Association of Human Milk Banks) was included. Implementation of these recommendations can contribute to promotion of breastfeeding.

Adherence to Mediterranean Diet of Breastfeeding Mothers and Fatty Acids Composition of Their Human Milk: Results From the Italian MEDIDIET Study.

Background and Aims: The content of fatty acids (FA) in human milk may be influenced by maternal nutrition. We evaluated the role of a Mediterranean diet in influencing the content of FA in human milk among 282 breastfeeding mothers participating in the MEDIDIET study. Materials and Methods: Mediterranean Diet Score (MDS), a composite index, was used to evaluate adherence to the Mediterranean diet. It includes 9 components (i.e., vegetables, fruit, cereals, legumes, monounsaturated to saturated FA ratio - MUFA/SFA, fish, dairy products, meat, and alcohol) and therefore potentially ranges from 0 (no adherence) to 9 (complete adherence) points. None of the mothers obtained the highest score due to the low alcohol consumption in the study population. Mothers were categorized in approximate tertiles of adherence: 0-3 (34.4%), 4 (26.2%), and 5-8 points (39.4%). The mean content of FA across categories of MDS was compared using ANOVA and test for trend. Results: A high adherence of breastfeeding mothers to the Mediterranean diet was associated with lower content of SFA in human milk (42.58 ± 4.36 for MDS = 0-3, 42.58 ± 4.89 for MDS = 4, and 40.92 ± 5.22% of fats for MDS = 5-8 points; p ANOVA and p for trend = 0.02). Conversely, a high adherence was associated with higher content of MUFA in human milk (43.27 ± 4.27 for MDS = 0-3, 43.27 ± 4.47 for MDS = 4, and 45.24 ± 5.22% of fats for MDS = 5-8 points; p ANOVA and p for trend < 0.01), ω-3 FA (1.07 ± 0.25 for MDS = 0-3, 1.22 ± 0.49 for MDS = 4, and 1.31 ± 0.51% of fats for MDS = 5-8 points; p ANOVA and p for trend < 0.01), and the major types of ω-3 FA (i.e., α-linolenic acid - ALA, eicosapentaenoic acid - EPA, docosahexaenoic acid - DHA, docosapentaenoic acid - DPA). These associations were mainly driven by the adherence to the vegetables, MUFA/SFA, fish, and dairy products components of the Mediterranean diet. Conclusion: A high adherence to the Mediterranean diet was associated with human milk showing a lower content of SFA and higher content of MUFA and ω-3 FA, including DHA. The Mediterranean diet may contribute in human milk production with higher content of specific FA which is directly involved in infant's neural and visual development, as reported by previous studies.

Human milk glycosaminoglycans inhibit cytomegalovirus and respiratory syncytial virus infectivity by impairing cell binding.

BACKGROUND: The antiviral role of glycosaminoglycans in human milk (HM-GAGs) has been poorly investigated. They are highly sulfated polysaccharides, which were proposed to act as decoy receptors according to their structure. The aim of this study is to evaluate the antiviral potential and the mechanism of action of total and individual HM-GAGs against three pediatric clinically relevant viruses: respiratory syncytial virus (RSV), cytomegalovirus (HCMV), and rotavirus. METHODS: HM-GAGs were isolated from HM and a library of individual GAGs, structurally related to HM-GAGs, was prepared. The antiviral activity of HM-GAGs and the impact of thermal treatment were investigated in vitro by specific antiviral assays. RESULTS: We demonstrated that HM-GAGs are endowed with anti-HCMV and anti-RSV activity and that they act by altering virus attachment to cell. We clarified the contribution of individual HM-GAGs, showing a specific structure-related activity. We did not observe any alteration of HM-GAG antiviral activity after thermal treatment. CONCLUSIONS: We showed that HM-GAGs contribute to the overall antiviral activity of HM, likely exerting a synergic action with other HM antiviral agents. HM-GAGs can now be added to the list of endogenous factors that may reduce breast-milk-acquired HCMV symptomatic infections and protecting infants from respiratory tract infections by RSV. IMPACT: HM-GAGs have been poorly investigated for their antiviral action so far. We demonstrated that HM-GAGs are endowed with significant anti-HCMV and anti-RSV activity and that they are able to alter virus binding to the cell. The contribution of individual HM-GAGs is mainly exerted by the FMHep and is not based on a simple charge interaction between the virus and sulfate groups but involves a specific GAG structural configuration. Our results contribute to identifying the multiple factors synergically acting in mediating HM antiviral properties and to clarifying their specific mechanism of action.

Analysis of Thermal Sensitivity of Human Cytomegalovirus Assayed in the Conventional Conditions of a Human Milk Bank.

One of the main concerns in human milk banks (HMB) is the transmission of human cytomegalovirus (HCMV) that could be present in the milk of infected women. There are consistent data showing that this virus is destroyed by Holder pasteurization (62.5°C for 30 min), but there is a lack of information about the response of the virus to the treatment at lower temperatures in strict HMB conditions. In order to analyze the effectiveness of different temperatures of pasteurization to eliminate HCMV in human milk, a preliminary assay was performed incubating HCMV-spiked raw milk samples from donor mothers at tested temperatures in a PCR thermocycler and the viral infectivity was assayed on cell cultures. No signs of viral replication were observed after treatments at temperatures equal or >53°C for 30, 20, and 10 min, 58°C for 5 min, 59°C for 2 min, and 60°C for 1 min. These data were confirmed in a pasteurizer-like model introducing HCMV-spiked milk in disposable baby bottles. No viral infectivity was detected on cell cultures after heating treatment of milk for 30 min at temperatures from 56 to 60°C. Thus, our results show that by using conventional pasteurization conditions, temperatures in the range of 56-60°C are enough to inactivate HCMV. Consequently, we consider that, in order to provide a higher quality product, the current recommendation to pasteurize both mother's own milk and donated milk at 62.5°C must be re-evaluated.

Dietary Intake of Breastfeeding Mothers in Developed Countries: A Systematic Review and Results of the MEDIDIET Study.

BACKGROUND: Lactation is a demanding period for women, and a good nutrition is crucial for optimal health of mothers and infants. OBJECTIVES: To provide new data and summarize the overall evidence on maternal nutrient intakes during lactation in developed countries, we present a systematic review (SR) of the literature and concurrently original results of the Italian MEDIDIET study. We compared nutrient intakes with dietary reference values (DRVs) proposed by the European Food Safety Authority. METHODS: Studies were identified searching PubMed/Embase databases up to February 2020. Observational studies reporting at least energy and macronutrient intakes of healthy breastfeeding mothers who followed non-restricted and non-specific diets were included. Studies on populations with severe nutritional deficiencies were excluded. The MEDIDIET study enrolled 300 healthy breastfeeding mothers at 6 ± 1 wk postpartum. Usual diet was concomitantly evaluated through a validated and reproducible FFQ. Nutrient intakes were estimated using a food composition database. RESULTS: Twenty-eight articles regarding 32 distinct study populations were included. Maternal nutrient intakes were generally in agreement across studies included in the SR and conforming to DRVs. Within micronutrients, vitamin D intake was below the recommendation. In the MEDIDIET study, mean intakes of energy (1950 ± 445 kcal/d), carbohydrates (270 ± 20.1 g/d), proteins (87.8 ± 20.1 g/d), and fats (65.6 ± 18.9 g/d) were similar to those observed in the SR. Moreover, observed intakes seemed to reflect the typical Mediterranean diet, with low intakes of carbohydrates, SFAs, and PUFAs and high intakes of MUFAs and vitamins. Conversely, protein intake was mainly derived from animal sources. CONCLUSIONS: This SR showed that nutrient intakes of breastfeeding mothers in developed countries are generally in line with DRVs despite different dietary patterns worldwide. Some nutritional deficiencies emerged, highlighting the need for additional nutritional advice. Mothers participating in the MEDIDIET study showed a nutritional profile in agreement with the Mediterranean diet.

Dietary Patterns of Breastfeeding Mothers and Human Milk Composition: Data from the Italian MEDIDIET Study.

(1) Background: Several studies have reported associations between maternal diet in terms of single foods or nutrients and human milk compounds, while the overall role of maternal diet and related dietary patterns has rarely been investigated. (2) Methods: Between 2012 and 2014, we enrolled 300 healthy Italian mothers, who exclusively breastfed their infant. During a hospital visit at 6 weeks postpartum, a sample of freshly expressed foremilk was collected and information on maternal dietary habits in the postpartum period was obtained through an interviewer-administered food frequency questionnaire. We applied principal component factor analysis to selected nutrients in order to identify maternal dietary patterns, and assessed correlations in human milk macronutrients and fatty acids across levels of dietary patterns. (3) Results: Five dietary patterns were identified, named "Vitamins, minerals and fibre", "Proteins and fatty acids with legs", "Fatty acids with fins", "Fatty acids with leaves", "Starch and vegetable proteins". These dietary patterns were correlated with some milk components, namely fatty acids, and in particular ω-3 and its subcomponents. (4) Conclusions: This study showed that overall maternal dietary habits during breastfeeding may influence human milk composition, suggesting the importance of adequate maternal nutrition during lactation not only for the mother herself but also to provide the infant with milk containing adequate amount and quality of nutrients for a balanced nutrition.

Human Colostrum and Derived Extracellular Vesicles Prevent Infection by Human Rotavirus and Respiratory Syncytial Virus in Vitro.

BACKGROUND: It is known that breastfeeding protects the infant from enteric and respiratory infections; however, the antiviral properties of human milk against enteric and respiratory viruses are largely unexplored. RESEARCH AIMS: To explore the antiviral activity of human preterm colostrum against rotavirus and respiratory syncytial virus and to assess whether the derived extracellular vesicle contribute to this activity. METHODS: We used a cross-sectional, prospective two-group non-experimental design. Colostra were collected from mothers of preterm newborns (N = 10) and extracellular vesicles were purified and characterized. The antiviral activity of colostra and derived extracellular vesicles were tested in vitro against rotavirus and respiratory syncytial virus and the step of viral replication inhibited by extracellular vesicles was investigated. RESULTS: Each sample of colostrum and colostrum-derived extracellular vesicles had significant antiviral activity with a wide interpersonal variability. Mechanism of action studies demonstrated that extracellular vesicles acted by interfering with the early steps of the viral replicative cycle. CONCLUSION: We demonstrated the intrinsic antiviral activity of human colostrum against rotavirus and respiratory syncytial virus and we showed that extracellular vesicles substantially contribute to the overall protective effect. Our results contribute to unravelling novel mechanisms underlying the functional role of human milk as a protective and therapeutic agent in preterm infants.

Detection of SARS-CoV-2 in Milk From COVID-19 Positive Mothers and Follow-Up of Their Infants.

Background: In the current SARS-Coronavirus-2 (SARS-CoV-2) pandemic little is known about SARS-CoV-2 in human milk. It is important to discover if breast milk is a vehicle of infection. Objective: Our aim was to look for the presence of SARS-CoV-2 RNA in the milk of a group of SARS-CoV-2 positive mothers from North-West Italy. Methods: This is a prospective collaborative observational study where samples of human milk from 14 breastfeeding mothers positive for SARS-CoV-2 were collected. A search of viral RNA in breast milk samples was performed by RT-PCR (Real-Time reverse-transcriptase-Polymerase-Chain-Reaction) methodology tested for human milk. All the newborns underwent a clinical follow up during the first month of life or until the finding of two sequential negative swabs. Results: In 13 cases the search for SARS-CoV-2 RNA in milk samples resulted negative and in one case it was positive. Thirteen of the 14 newborns were exclusively breastfed and closely monitored in the first month of life. Clinical outcome was uneventful. Four newborns tested positive for SARS-CoV-2 and were all detected in the first 48 h of life, after the onset of maternal symptoms. Also the clinical course of these 4 infants, including the one who received mother's milk positive for SARS-CoV-2, was uneventful, and all of them became SARS-CoV-2 negative within 6 weeks of life. Conclusion: Our study supports the view that SARS-CoV-2 positive mothers do not expose their newborns to an additional risk of infection by breastfeeding.

Anti-Zika virus and anti-Usutu virus activity of human milk and its components.

The benefits of human milk are mediated by multiple nutritional, trophic, and immunological components, able to promote infant's growth, maturation of its immature gut, and to confer protection against infections. Despite these widely recognized properties, breast-feeding represents an important mother-to-child transmission route of some viral infections. Different studies show that some flaviviruses can occasionally be detected in breast milk, but their transmission to the newborn is still controversial. The aim of this study is to investigate the antiviral activity of human milk (HM) in its different stages of maturation against two emerging flaviviruses, namely Zika virus (ZIKV) and Usutu virus (USUV) and to verify whether HM-derived extracellular vesicles (EVs) and glycosaminoglycans (GAGs) contribute to the milk protective effect. Colostrum, transitional and mature milk samples were collected from 39 healthy donors. The aqueous fractions were tested in vitro with specific antiviral assays and EVs and GAGs were derived and characterized. HM showed antiviral activity against ZIKV and USUV at all the stages of lactation with no significant differences in the activity of colostrum, transitional or mature milk. Mechanism of action studies demonstrated that colostrum does not inactivate viral particles, but it hampers the binding of both flaviviruses to cells. We also demonstrated that HM-EVs and HM-GAGs contribute, at least in part, to the anti-ZIKV and anti-USUV action of HM. This study discloses the intrinsic antiviral activity of HM against ZIKV and USUV and demonstrates the contribution of two bioactive components in mediating its protective effect. Since the potential infectivity of HM during ZIKV and USUV infection is still unclear, these data support the World Health Organization recommendations about breast-feeding during ZIKV infection and could contribute to producing new guidelines for a possible USUV epidemic.

Extracellular Vesicles in Human Preterm Colostrum Inhibit Infection by Human Cytomegalovirus In Vitro.

Breast milk is a complex biofluid that nourishes infants, supports their growth and protects them from diseases. However, at the same time, breastfeeding is a transmission route for human cytomegalovirus (HCMV), with preterm infants being at a great risk of congenital disease. The discrepancy between high HCMV transmission rates and the few reported cases of infants with severe clinical illness is likely due to the protective effect of breast milk. The aim of this study was to investigate the anti-HCMV activity of human preterm colostrum and clarify the role of colostrum-derived extracellular vesicles (EVs). Preterm colostrum samples were collected and the EVs were purified and characterized. The in vitro anti-HCMV activity of both colostrum and EVs was tested against HCMV, and the viral replication step inhibited by colostrum-purified EVs was examined. We investigated the putative role EV surface proteins play in impairing HCMV infection using shaving experiments and proteomic analysis. The obtained results confirmed the antiviral action of colostrum against HCMV and demonstrated a remarkable antiviral activity of colostrum-derived EVs. Furthermore, we demonstrated that EVs impair the attachment of HCMV to cells, with EV surface proteins playing a role in mediating this action. These findings contribute to clarifying the mechanisms that underlie the protective role of human colostrum against HCMV infection.

Effects on Gastroesophageal Reflux of Donkey Milk-Derived Human Milk Fortifier Versus Standard Fortifier in Preterm Newborns: Additional Data from the FortiLat Study.

BACKGROUND: Feeding intolerance is a frequent diagnosis in very preterm infants. As seen in the FortiLat trial, human milk fortification with the new donkey milk-derived human milk fortifier (DF) seems to improve feeding tolerance in these infants. The aim of this study was to evaluate the effects of using the DF compared with bovine milk-derived fortifier (BF) on gastroesophageal reflux (GER) in very low birth weight (VLBW) infants. METHODS: Over a total of 156 preterm infants were enrolled into the FortiLat trial (GA <32 weeks and birth weight <1500 g) and randomized into the BF arm or DF arm, and we selected all infants with clinical signs of GER and cardiorespiratory (CR) symptoms. All the infants underwent CR and multichannel intraluminal impedance and pH (MII/pH) monitoring associated with gastric ultrasound to evaluate GER and gastric emptying time. RESULTS: 10 infants were enrolled, and 5 were in the DF arm. At MII/pH, infants enrolled into the DF arm showed a lower GER frequency than BF arm infants (p = 0.036). Half gastric emptying time was similar in DF and BF arm infants (p = 0.744). CONCLUSION: The use of donkey-derived human milk fortifier reduced the GER frequency and consequently should be recommended in infants with feeding intolerance.

Antiviral oxysterols are present in human milk at diverse stages of lactation.

Oxysterols are cholesterol oxidation derivatives. Those containing an additional hydroxyl group on the side chain of the cholesterol molecule result from a physiological enzymatic synthesis and include the majority of oxysterols present in the circulation. Among these, 25-hydroxycholesterol (25OHC) and 27-hydroxycholesterol (27OHC) are characterized by a broad antiviral activity and are now considered involved in the innate immune response against viruses. Despite the emerging role of these sterols in the innate antiviral defences, no data are available on their presence in human breast milk (BM) to date. In this study, we investigated the content of oxysterols of enzymatic synthesis in BM of twelve donor mothers at different stages of lactation (i.e. in colostrum, transitional milk, and mature milk) by gas chromatography-mass spectrometry analysis. The side-chain oxysterols 25OHC, 27OHC, and 24S-hydroxycholesterol (24SOHC) were actually present in BM in all stages of lactation, but the concentration of 27OHC showed a remarkable peak in colostrum. Antiviral assays revealed that all the colostrum samples contained 27OHC concentrations that were active in vitro against two relevant pediatric viral pathogens: the human rotavirus and the human rhinovirus. Overall, this study discloses new antiviral components of BM and suggests a passive transfer of these protective factors to the infant via breastfeeding, especially in the first few days of lactation.

Fortification of Human Milk for Preterm Infants: Update and Recommendations of the European Milk Bank Association (EMBA) Working Group on Human Milk Fortification.

Evidence indicates that human milk (HM) is the best form of nutrition uniquely suited not only to term but also to preterm infants conferring health benefits in both the short and long-term. However, HM does not provide sufficient nutrition for the very low birth weight (VLBW) infant when fed at the usual feeding volumes leading to slow growth with the risk of neurocognitive impairment and other poor health outcomes such as retinopathy and bronchopulmonary dysplasia. HM should be supplemented (fortified) with the nutrients in short supply, particularly with protein, calcium, and phosphate to meet the high requirements of this group of babies. In this paper the European Milk Bank Association (EMBA) Working Group on HM Fortification discusses the existing evidence in this field, gives an overview of different fortification approaches and definitions, outlines the gaps in knowledge and gives recommendations for practice and suggestions for future research. EMBA recognizes that "Standard Fortification," which is currently the most utilized regimen in neonatal intensive care units, still falls short in supplying sufficient protein for some VLBW infants. EMBA encourages the use of "Individualized Fortification" to optimize nutrient intake. "Adjustable Fortification" and "Targeted Fortification" are 2 methods of individualized fortification. The quality and source of human milk fortifiers constitute another important topic. There is work looking at human milk derived fortifiers, but it is still too early to draw precise conclusions about their use. The pros and cons are discussed in this Commentary in addition to the evidence around use of fortifiers post discharge.

Adherence to the Traditional Mediterranean Diet and Human Milk Composition: Rationale, Design, and Subject Characteristics of the MEDIDIET Study.

Introduction: Knowledge about how a lactating woman's diet influences the composition of her breast milk is still very limited. In particular, no study has evaluated the role of adherence to the Mediterranean diet on human milk characteristics. Aim: We carried out an observational study to investigate the influence of mother adherence to a Mediterranean diet on her breast milk composition. Methods: Between 2012 and 2014, 300 healthy mothers, who exclusively breastfed their babies, were enrolled from five centers across Italy. During a visit to the hospital center 6 weeks after childbirth these women were asked to provide a sample of their freshly expressed breast milk and to answer a series of questions on personal characteristics and lifestyle factors. The application of a validated food frequency questionnaire allowed the collection of detailed dietary habits. Milk was collected and then stored until chemical analyses were performed. The study has been registered (Trial Registration: Dutch Trial register NTR3468). Descriptive analyses on baseline characteristics of mothers and babies were carried out on the participants, overall and stratified by center. Results: The participants had a mean age of 33 years (SD = 4.06), and a pre-pregnancy BMI of 22.3 Kg/m2 (SD = 3.22). Forty-seven percent gave birth to their first child, 40% to the second 13% to the third or subsequent child. Babies had a mean birth weight of 3,324 g (DS = 389), and a mean length of 51 cm (SD = 1.94). Fifty-three percent were males. Conclusion: The present work provides the general description and the characteristics of mothers and babies included in the MediDiet study.

Letter to the editor: clarifying some aspects and the terminology of individualized human milk fortification.

This letter has been written by the components of the European Milk Bank Association (EMBA) Working Group on Human Milk Fortification in response to a recent paper published by Mathes et al. (BMC Pediatr. 2018 May 8;18(1):154) with the aim of drawing attention to the importance of the use of a metabolic marker to adapt protein intake in preterm infants. EMBA Working Group on Human Milk Fortification clarifies further the terminology and some specific aspects regarding individualized human milk fortification. There are two types of individualized human milk fortification: Adjustable human milk fortification and Targeted human milk fortification. Advantages and disadvantages of these methods are summarized.

A Novel Donkey Milk-derived Human Milk Fortifier in Feeding Preterm Infants: A Randomized Controlled Trial.

OBJECTIVES: The purpose of the present randomized controlled clinical trial was to compare the use of donkey milk-derived fortifier (DF) with commercial bovine milk-derived fortifier (BF) in very preterm or very-low-birth-weight newborns, in terms of feeding tolerance. METHODS: This trial included 156 newborns born at <32 weeks of gestational age and/or with a birth weight ≤1500 g. Newborns were randomized 1:1 to receive enteral feeding with either a BF-arm, or a new, DF-arm for 21 days. The fortification protocol was the same for both study arms, and the 2 diets were designed to be isoproteic and isocaloric. Feeding tolerance was assessed by a standardized protocol. RESULTS: The risk of feeding intolerance tended to be lower in DF-arm than in BF-arm, with a relative risk reduction of 0.63 (95% confidence interval: -0.29, +0.90). The mean number of episodes per newborn of feeding intolerance and feeding interruptions (any duration) were consistently lower in the DF-arm than in the BF-arm. Episodes of bilious gastric residuals and vomiting were significantly lower in the DF-arm. Time needed to reach full enteral feeding (150 mL ·â€Škg ·â€Šday) and daily weight increase between the first day of exclusive enteral feeding (ie, without administering intravenous fluids) and discharge were similar in the BF- and DF-arms. CONCLUSIONS: These results suggest that DF improve feeding tolerance when compared with standard bovine-derived fortifiers, with a similar auxological outcome.

High Temperature-Short Time Pasteurization Has a Lower Impact on the Antiviral Properties of Human Milk Than Holder Pasteurization.

Holder pasteurization (62. 5°C for 30 min) is recommended by all international human milk bank guidelines to prevent infections potentially transmitted by donor human milk. A drawback is that it affects some human milk bioactive and nutritive components. Recently, High Temperature-Short Time (HTST) pasteurization has been reported to be a valuable alternative technology to increase the retention of some biological features of human milk. Nevertheless, to date, few data are available about the impact of pasteurization methods other than Holder on the antiviral activity of human milk. The present study was aimed at evaluating the antiviral activity of human milk against a panel of viral pathogens common in newborns and children (i.e., herpes simplex virus 1 and 2, cytomegalovirus, respiratory syncytial virus, rotavirus, and rhinovirus), and at assessing the effect of Holder and HTST pasteurization on milk's antiviral properties. The results indicate that human milk is endowed with antiviral activity against all viruses tested, although to a different extent. Unlike the Holder pasteurization, HTST preserved the inhibitory activity against cytomegalovirus, respiratory syncytial virus, rotavirus and herpes simplex virus type 2. By contrast, both methods reduced significantly the antiviral activities against rhinovirus and herpes simplex virus type 1. Unexpectedly, Holder pasteurization improved milk's anti-rotavirus activity. In conclusion, this study contributes to the definition of the pasteurization method that allows the best compromise between microbiological safety and biological quality of the donor human milk: HTST pasteurization preserved milk antiviral activity better than Holder.

Anti-Cytomegalovirus Activity in Human Milk and Colostrum From Mothers of Preterm Infants.

OBJECTIVES: This study aimed to investigate the anti-human cytomegalovirus (CMV) activity of milk from seropositive and seronegative mothers of preterm infants and to analyze its changes throughout the different stages of lactation and after Holder pasteurization, a procedure adopted by donor human milk banks. METHODS: Eighteen mothers of preterm infants were enrolled in the study. Colostrum, transitional milk, and mature milk samples were collected and tested for anti-CMV activity. Depletion of immunoglobulins A from milk samples was carried out by jacalin resin. Pools of milk samples were pasteurized according to Holder technique. RESULTS: All samples were endowed with anti-CMV activity, although to a different extent. In CMV IgG-positive mothers, colostra were significantly more active than the transitional milk and mature milk samples. Moreover, they were more potent than colostra from seronegative mothers. Immunoglobulins A depletion in colostra from IgG-positive mothers resulted in a partial loss of anti-CMV activity. Holder pasteurization significantly reduced the antiviral activity. CONCLUSIONS: Human milk is endowed with anti-CMV activity and its potency may vary depending on the stage of lactation and the serological status of the mother. This biological property could partially neutralize CMV particles excreted in the milk of CMV IgG-positive mothers thus reducing the risk of transmitting infectious viruses to the infant.

Nutritional adequacy of a novel human milk fortifier from donkey milk in feeding preterm infants: study protocol of a randomized controlled clinical trial.

BACKGROUND: Fortification of human milk is a standard practice for feeding very low birth weight infants. However, preterm infants often still experience suboptimal growth and feeding intolerance. New fortification strategies and different commercially available fortifiers have been developed. Commercially available fortifiers are constituted by a blend of ingredients from different sources, including plant oils and bovine milk proteins, thus presenting remarkable differences in the quality of macronutrients with respect to human milk. Based on the consideration that donkey milk has been suggested as a valid alternative for children allergic to cow's milk proteins, due to its biochemical similarity to human milk, we hypothesized that donkey milk could be a suitable ingredient for developing an innovative human milk fortifier. The aim of the study is to evaluate feeding tolerance, growth and clinical short and long-term outcomes in a population of preterm infants fed with a novel multi-component fortifier and a protein concentrate derived from donkey milk, in comparison to an analogous population fed with traditional fortifier and protein supplement containing bovine milk proteins. METHODS: The study has been designed as a randomized, controlled, single-blind clinical trial. Infants born <1500 g and <32 weeks of gestational age were randomized to receive for 21 days either a combination of control bovine milk-based multicomponent fortifier and protein supplement, or a combination of a novel multicomponent fortifier and protein supplement derived from donkey milk. The fortification protocol followed is the same for the two groups, and the two diets were designed to be isoproteic and isocaloric. Weight, length and head circumference are measured; feeding tolerance is assessed by a standardized protocol. The occurrence of sepsis, necrotizing enterocolitis and adverse effects are monitored. DISCUSSION: This is the first clinical study investigating the use of a human milk fortifier derived from donkey milk for the nutrition of preterm infants. If donkey milk derived products will be shown to improve the feeding tolerance or either of the clinical, metabolic, neurological or auxological outcomes of preterm infants, it would be an absolute innovation in the field of feeding practices for preterm infants. TRIAL REGISTRATION: ISRCTN - ISRCTN70022881 .