Inactivation of human immunodeficiency virus type I in human milk: effects of intrinsic factors in human milk and of pasteurization

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.

Sterilization efficacy of a new water-free breast milk pasteurizer

BACKGROUND

Breast milk, nature's optimum source of nutrition for infants, can contain undesirable microorganisms that cause severe morbidity. After an outbreak of multidrug-resistant Escherichia coli among neonates receiving breast milk donated by another mother in our neonatal intensive care unit (NICU), we were motivated to develop a high-grade breast milk pasteurizer (BMP) designed to thaw and pasteurize breast milk at 63°C for 30 min in a sealed bag without having to open the bag or immerse it in water.

METHODS

Pre-existing bacteria and spiked cytomegalovirus (CMV) were measured pre- and post-pasteurization in frozen breast milk donated by mothers of children admitted to the NICU.

RESULTS

Among 48 breast milk samples (mean ± standard deviation [SD]), pre-existing bacterial counts of 5.1±1.1 × 104 colony forming units (cfu)/mL decreased to less than 10 cfu/mL (below detection level) in 45 samples after pasteurization for 30 min. In three samples, 10-110 cfu/mL persisted. As no CMV was detected in any of the 48 samples, CMV at ≥5 × 104 pfu/mL was spiked into 11 breast milk samples. After just 10 min of pasteurization, infectious CMV was not detected (threshold <50 pfu/mL) in any sample.

CONCLUSION

A new BMP was shown to pasteurize milk effectively with more than a 3-log reduction of microorganisms. Compared to conventional pasteurizers, this device reduces the effort involved in pasteurizing breast milk, avoids various contamination risks, and may reduce the risk of infectious disease transmission via breast milk.

Mother-to-Child Transmission of Arboviruses during Breastfeeding: From Epidemiology to Cellular Mechanisms

Most viruses use several entry sites and modes of transmission to infect their host (parenteral, sexual, respiratory, oro-fecal, transplacental, transcutaneous, etc.). Some of them are known to be essentially transmitted via arthropod bites (mosquitoes, ticks, phlebotomes, sandflies, etc.), and are thus named arthropod-borne viruses, or arboviruses. During the last decades, several arboviruses have emerged or re-emerged in different countries in the form of notable outbreaks, resulting in a growing interest from scientific and medical communities as well as an increase in epidemiological studies. These studies have highlighted the existence of other modes of transmission. Among them, mother-to-child transmission (MTCT) during breastfeeding was highlighted for the vaccine strain of yellow fever virus (YFV) and Zika virus (ZIKV), and suggested for other arboviruses such as Chikungunya virus (CHIKV), dengue virus (DENV), and West Nile virus (WNV). In this review, we summarize all epidemiological and clinical clues that suggest the existence of breastfeeding as a neglected route for MTCT of arboviruses and we decipher some of the mechanisms that chronologically occur during MTCT via breastfeeding by focusing on ZIKV transmission process.

The impact of thermal pasteurization on viral load and detectable live viruses in human milk and other matrices: a rapid review

Holder pasteurization (62.5 °C, 30 min) of human milk is thought to reduce the risk of transmitting viruses to an infant. Some viruses may be secreted into milk - others may be contaminants. The effect of thermal pasteurization on viruses in human milk has yet to be rigorously reviewed. The objective of this study is to characterize the effect of common pasteurization techniques on viruses in human milk and non-human milk matrices. Databases (MEDLINE, Embase, Web of Science) were searched from inception to April 20th, 2020, for primary research articles assessing the impact of pasteurization on viral load or detection of live virus. Reviews were excluded, as were studies lacking quantitative measurements or those assessing pasteurization as a component of a larger process. Overall, of 65 131 reports identified, 109 studies were included. Pasteurization of human milk at a minimum temperature of 56-60 °C is effective at reducing detectable live virus. In cell culture media or plasma, coronaviruses (e.g., SARS-CoV, SARS-CoV-2, MERS-CoV) are highly susceptible to heating at ≥56 °C. Although pasteurization parameters and matrices reported vary, all viruses studied, except parvoviruses, were susceptible to thermal killing. Future research important for the study of novel viruses should standardize pasteurization protocols and should test inactivation in human milk. Novelty In all matrices, including human milk, pasteurization at 62.5 °C was generally sufficient to reduce surviving viral load by several logs or to below the limit of detection. Holder pasteurization (62.5 °C, 30 min) of human milk should be sufficient to inactivate nonheat resistant viruses, including coronaviruses, if present.

The Associations Between Light Exposure During Pumping and Holder Pasteurization and the Macronutrient and Vitamin Concentrations in Human Milk

BACKGROUND

During pumping, storage, and pasteurization human milk is exposed to light, which could affect the concentrations of light-sensitive vitamins. Currently, milk banks do not regulate light exposure.

RESEARCH AIM

The aim of this paper was to determine the influence of light exposure during pumping, storage, and pasteurization on (1) macronutrients, (2) select water-soluble vitamins, and (3) select fat-soluble vitamins.

METHODS

All 13 participants donated 4 milk samples each. Each sample underwent 1 of 4 treatments: raw and light protected, raw and light exposed, pasteurized and light protected, and pasteurized and light exposed. Samples were analyzed for macronutrients and Vitamins B₁, B₂, retinol, γ-tocopherol, α-tocopherol, and β-carotene.

RESULTS

β-carotene concentrations were not influenced by light exposure. Vitamin B₁ was significantly (p < 0.05) affected by light-exposure (M = 0.23, SD = 0.01mg/L) compared to light-protected (M = 0.27, SD = 0.01mg/L) samples. Vitamin B₂ concentrations were reduced (p < 0.05) by light-exposure in raw (M = 62.1, SD = 0.61µg/L) and pasteurized (M = 73.7, SD = 0.72µg/L) samples compared to light-protected raw samples (M = 99.7, SD = 0.66µg/L). No other tested nutrients were affected by light exposure.

CONCLUSIONS

If milk is exposed to excessive amounts of light, Vitamins B₁ and B₂ concentrations may degrade below the current Adequate Intake recommendations for infants 0-6 months of age, increasing the risk of insufficient vitamin supply to the exclusively human milk-fed infant. Thus, pumped or processed human milk should be protected from light to preserve milk vitamin concentrations.

Innovative Techniques of Processing Human Milk to Preserve Key Components

Human milk not only contains all nutritional elements that an infant requires, but is also the source of components whose regulatory role was confirmed by demonstrating health-related deficiencies in formula-fed children. A human milk diet is especially important for premature babies in the neonatal intensive care unit (NICU). In cases where breastfeeding is not possible and the mother's own milk is insufficient in volume, the most preferred food is pasteurized donor milk. The number of human milk banks has increased recently but their technical infrastructure is continuously developing. Heat treatment at a low temperature and long time, also known as holder pasteurization (62.5 °C, 30 min), is the most widespread method of human milk processing, whose effects on the quality of donor milk is well documented. Holder pasteurization destroys vegetative forms of bacteria and most viruses including human immunodeficiency virus (HIV) herpes and cytomegalovirus (CMV). The macronutrients remain relatively intact but various beneficial components are destroyed completely or compromised. Enzymes and immune cells are the most heat sensitive elements. The bactericidal capacity of heat-pasteurized milk is lower than that of untreated milk. The aim of the study was for a comprehensive comparison of currently tested methods of improving the preservation stage. Innovative techniques of milk processing should minimize the risk of milk-borne infections and preserve the bioactivity of this complex biological fluid better than the holder method. In the present paper, the most promising thermal pasteurization condition (72 °C-75 °C,) and a few non-thermal processes were discussed (high pressure processing, microwave irradiation). This narrative review presents an overview of methods of human milk preservation that have been explored to improve the safety and quality of donor milk.

Differences in Maternal Immunoglobulins within Mother's Own Breast Milk and Donor Breast Milk and across Digestion in Preterm Infants

Maternal antibody transfer to the newborn provides essential support for the infant’s naïve immune system. Preterm infants normally receive maternal antibodies through mother’s own breast milk (MBM) or, when mothers are unable to provide all the milk required, donor breast milk (DBM). DBM is pasteurized and exposed to several freeze–thaw cycles, which could reduce intact antibody concentration and the antibody’s resistance to digestion within the infant. Whether concentrations of antibodies in MBM and DBM differ and whether their survival across digestion in preterm infants differs remains unknown. Feed (MBM or DBM), gastric contents (MBM or DBM at 1-h post-ingestion) and stool samples (collected after a mix of MBM and DBM feeding) were collected from 20 preterm (26–36 weeks gestational age) mother–infant pairs at 8–9 and 21–22 days of postnatal age. Samples were analyzed via ELISA for the concentration of secretory IgA (SIgA), total IgA (SIgA/IgA), total IgM (SIgM/IgM) and IgG. Total IgA, SIgA, total IgM and IgG concentrations were 55.0%, 71.6%, 98.4% and 41.1% higher in MBM than in DBM, and were 49.8%, 32.7%, 73.9% and 39.7% higher in gastric contents when infants were fed with MBM than when infants were fed DBM, respectively. All maternal antibody isotypes present in breast milk were detected in the infant stools, of which IgA (not sIgA) was the most abundant.

Processing of Donor Human Milk: Update and Recommendations From the European Milk Bank Association (EMBA)

Background: A mother's own milk (MOM) is the gold standard for the feeding and nutrition of preterm and full term infants. When MOM is not available or there is not enough, donor human milk (DHM) should be used. Milk delivered to Human Milk Banks (HMBs) should be pasteurized to inactivate viral and bacterial agents. Currently, a pasteurization process at 62.5°C for 30 min (Holder pasteurization, HoP) is recommended in all international HMBs guidelines. State of the art: It is known that HoP affects some of the nutritional and biological components of human milk. Studies have demonstrated that temperature cycle in HoP is not always controlled or calibrated. A better check of these parameters in the pasteurizers on the market today may contribute to an improvement of the quality of HM, still maintaining some of the negative effects of the heat treatment of human milk. So, food industry, and dairy industry in particular, are evaluating innovative methodologies alternative to HoP to better preserve the nutritional and biological properties of fresh human milk, while assuring at least the same microbiological safety of HoP. The most studied processing techniques include High-Temperature-Short-Time (HTST) pasteurization, High Pressure Processing (HPP), and Ultraviolet-C (UV-C) irradiation. HTST is a thermal process in which milk is forced between plates or pipes that are heated on the outside by hot water at a temperature of 72°C for 5-15 s. HPP is a non-thermal processing method that can be applied to solid and liquid foods. This technology inactivates pathogenic microorganisms by applying a high hydrostatic pressure (usually 300-800 MPa) during short-term treatments (<5-10 min). UV irradiation utilizes short-wavelength ultraviolet radiation in the UV-C region (200-280 nm), which is harmful to microorganisms. It is effective in destroying the nucleic acids in these organisms, so that their DNA is disrupted by UV radiation. Aim: The aim of this paper is to present the EMBA recommendations on processing of HM, based on the most recent results obtained with these new technologies. Conclusions: Although research on the most promising technologies that will represent an alternative to HoP (HTST, HPP, UV-C) in the future is progressing, it is now important to recognize that the consistency and quality assurance of the pasteurizers on the market today represent a fundamental component that was previously lacking in the Holder approach.

Strategies for the Preservation, Restoration and Modulation of the Human Milk Microbiota. Implications for Human Milk Banks and Neonatal Intensive Care Units

Studies carried in the last years have revealed that human milk contains a site-specific microbiota and constitutes a source of potentially beneficial bacteria to the infant gut. Once in the infant gut, these bacteria contribute to the assembly of a physiological gut microbiota and may play several functions, contributing to infant metabolism, protection against infections, immunomodulation or neuromodulation. Many preterm neonates are fed with pasteurized donor's human milk (DHM) or formula and, therefore, are devoid of contact with human milk microbes. As a consequence, new strategies are required to allow the exposition of a higher number of preterm infants to the human milk microbiota early in life. The first strategy would be to promote and to increase the use of own mother's milk (OMM) in Neonatal Intensive Care Units (NICUs). Even small quantities of OMM can be very valuable since they would be added to DHM in order to microbiologically "customize" it. When OMM is not available, a better screening of donor women, including routine cytomegalovirus (CMV) screening of milk, may help to avoid the pasteurization of the milk provided by, at least, a relevant proportion of donors. Finally, when pasteurized DHM or formula are the only feeding option, their supplementation with probiotic bacteria isolated from human milk, such as lactic acid bacteria or bifidobacteria, may be an alternative to try to restore a human milk-like microbiota before feeding the babies. In the future, the design of human milk bacterial consortia (minimal human milk microbiotas), including well characterized strains representative of a healthy human milk microbiota, may be an attractive strategy to provide a complex mix of strains specifically tailored to this target population.

High-Temperature Short-Time Pasteurization System for Donor Milk in a Human Milk Bank Setting

Donor milk is the best alternative for the feeding of preterm newborns when mother's own milk is unavailable. For safety reasons, it is usually pasteurized by the Holder method (62.5°C for 30 min). Holder pasteurization results in a microbiological safe product but impairs the activity of many biologically active compounds such as immunoglobulins, enzymes, cytokines, growth factors, hormones or oxidative stress markers. High-temperature short-time (HTST) pasteurization has been proposed as an alternative for a better preservation of some of the biological components of human milk although, at present, there is no equipment available to perform this treatment under the current conditions of a human milk bank. In this work, the specific needs of a human milk bank setting were considered to design an HTST equipment for the continuous and adaptable (time-temperature combination) processing of donor milk. Microbiological quality, activity of indicator enzymes and indices for thermal damage of milk were evaluated before and after HTST treatment of 14 batches of donor milk using different temperature and time combinations and compared to the results obtained after Holder pasteurization. The HTST system has accurate and simple operation, allows the pasteurization of variable amounts of donor milk and reduces processing time and labor force. HTST processing at 72°C for, at least, 10 s efficiently destroyed all vegetative forms of microorganisms present initially in raw donor milk although sporulated Bacillus sp. survived this treatment. Alkaline phosphatase was completely destroyed after HTST processing at 72 and 75°C, but γ-glutamil transpeptidase showed higher thermoresistance. Furosine concentrations in HTST-treated donor milk were lower than after Holder pasteurization and lactulose content for HTST-treated donor milk was below the detection limit of analytical method (10 mg/L). In conclusion, processing of donor milk at 72°C for at least 10 s in this HTST system allows to achieve the microbiological safety objectives established in the milk bank while having a lower impact regarding the heat damage of the milk.

Mucus and Mucins: do they have a role in the inhibition of the human immunodeficiency virus?

BACKGROUND

Mucins are large O-linked glycosylated proteins which give mucus their gel-forming properties. There are indications that mucus and mucins in saliva, breast milk and in the cervical plug inhibit the human immunodeficiency virus (HIV-1) in an in vitro assay. Crude mucus gels form continuous layers on the epithelial surfaces of the major internal tracts of the body and protect these epithelial surfaces against aggressive luminal factors such as hydrochloric acid and pepsin proteolysis in the stomach lumen, the movement of hard faecal pellets in the colon at high pressure, the effects of shear against the vaginal epithelium during intercourse and the presence of foreign substances in the respiratory airways. Tumour-associated epitopes on mucins make them suitable as immune-targets on malignant epithelial cells, rendering mucins important as diagnostic and prognostic markers for various diseases, even influencing the design of mucin-based vaccines. Sub-Saharan Africa has the highest prevalence of HIV-AIDS in the world. The main points of viral transmission are via the vaginal epithelium during sexual intercourse and mother-to-child transmission during breast-feeding. There have been many studies showing that several body fluids have components that prevent the transmission of HIV-1 from infected to non-infected persons through various forms of contact. Crude saliva and its purified mucins, MUC5B and MUC7, and the purified mucins from breast milk, MUC1 and MUC4 and pregnancy plug cervical mucus (MUC2, MUC5AC, MUC5B and MUC6), inhibit HIV-1 in an in vitro assay. There are conflicting reports of whether crude breast-milk inhibits HIV-1 in an in vitro assay. However studies with a humanised BLT mouse show that breast-milk does inhibit HIV and that breast-feeding is still advisable even amongst HIV-positive women in under-resourced areas, preferably in conjunction with anti-retroviral treatment.

CONCLUSION

These findings raise questions of how such a naturally occurring biological substance such as mucus, with remarkable protective properties of epithelial surfaces against aggressive luminal factors in delicate locations, could be used as a tool in the fight against HIV-AIDS, which has reached epidemic proportions in sub-Saharan Africa.

Ebola Virus and Marburg Virus in Human Milk Are Inactivated by Holder Pasteurization

BACKGROUND

Potential donors of human milk are screened for Ebola virus (EBOV) using standard questions, but testing for EBOV and Marburg virus (MARV) is not part of routine serological testing performed by milk banks. Research aim: This study tested the hypothesis that EBOV would be inactivated in donor human milk (DHM) by standard pasteurization techniques (Holder) used in all North American nonprofit milk banks.

METHODS

Milk samples were obtained from a nonprofit milk bank. They were inoculated with EBOV (Zaire strain) and MARV (Angola strain) and processed by standard Holder pasteurization technique. Plaque assays for EBOV and MARV were performed to detect the presence of virus after pasteurization.

RESULTS

Neither EBOV nor MARV was detectable by viral plaque assay in DHM or culture media samples, which were pasteurized by the Holder process.

CONCLUSION

EBOV and MARV are safely inactivated in human milk by standard Holder pasteurization technique. Screening for EBOV or MARV beyond questionnaire and self-deferral is not needed to ensure safety of DHM for high-risk infants.

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.

Breast Milk of HIV-Positive Mothers Has Potent and Species-Specific In Vivo HIV-Inhibitory Activity

Despite the nutritional and health benefits of breast milk, breast milk can serve as a vector for mother-to-child HIV transmission. Most HIV-infected infants acquire HIV through breastfeeding. Paradoxically, most infants breastfed by HIV-positive women do not become infected. This is potentially attributed to anti-HIV factors in breast milk. Breast milk of HIV-negative women can inhibit HIV infection. However, the HIV-inhibitory activity of breast milk from HIV-positive mothers has not been evaluated. In addition, while significant differences in breast milk composition between transmitting and nontransmitting HIV-positive mothers have been correlated with transmission risk, the HIV-inhibitory activity of their breast milk has not been compared. This knowledge may significantly impact the design of prevention approaches in resource-limited settings that do not deny infants of HIV-positive women the health benefits of breast milk. Here, we utilized bone marrow/liver/thymus humanized mice to evaluate the in vivo HIV-inhibitory activity of breast milk obtained from HIV-positive transmitting and nontransmitting mothers. We also assessed the species specificity and biochemical characteristics of milk's in vivo HIV-inhibitory activity and its ability to inhibit other modes of HIV infection. Our results demonstrate that breast milk of HIV-positive mothers has potent HIV-inhibitory activity and indicate that breast milk can prevent multiple routes of infection. Most importantly, this activity is unique to human milk. Our results also suggest multiple factors in breast milk may contribute to its HIV-inhibitory activity. Collectively, our results support current recommendations that HIV-positive mothers in resource-limited settings exclusively breastfeed in combination with antiretroviral therapy.

IMPORTANCE

Approximately 240,000 children become infected with HIV annually, the majority via breastfeeding. Despite daily exposure to virus in breast milk, most infants breastfed by HIV-positive women do not acquire HIV. The low risk of breastfeeding-associated HIV transmission is likely due to antiviral factors in breast milk. It is well documented that breast milk of HIV-negative women can inhibit HIV infection. Here, we demonstrate, for the first time, that breast milk of HIV-positive mothers (nontransmitters and transmitters) inhibits HIV transmission. We also demonstrate that breast milk can prevent multiple routes of HIV acquisition and that this activity is unique to human milk. Collectively, our results support current guidelines which recommend that HIV-positive women in resource-limited settings exclusively breastfeed in combination with infant or maternal antiretroviral therapy.

Effect of fortifiers and additional protein on the osmolarity of human milk: is it still safe for the premature infant?

OBJECTIVES

The present guidelines of the American Academy of Pediatrics recommend that osmolarity not exceed 450 mOsm/kg (or approximately an osmolarity of 400 mOsm/L) for breast milk or infant formulae, to minimize the risk factors for necrotizing enterocolitis. A commercial protein supplement has been developed to meet special protein requirements (4.0-4.5 g · kg(-1) · day(-1)) of infants with a birth weight <1000 g. Because its effect on osmolarity has not been systematically studied, we characterized the effects of fortification on the osmolarity of human milk (HM).

METHODS

Osmolarity of fresh and processed HM was measured at baseline, after fortification with a commercial HM fortifier and after further supplementation with additional protein increasing in 0.5-g steps up to 4.0 g. Measurements were performed immediately after adding fortifier and/or protein and after 24 hours. In addition, changes in osmolarity were determined after adding therapeutic additives such as iron, multivitamin supplement, and calcium-phosphorus capsules.

RESULTS

Native HM samples (n = 84) had 297 mOsm/L, (median; 95% confidence interval 295-299 mOsm/L). Adding HM fortifier increased osmolarity up to 436 mOsm/L (95% confidence interval 431-441 mOsm/L). Additional protein supplementation increased osmolarity by 23.5 mOsm/L per 0.5-g step, up to a maximum of 605 mOsm/L. Pasteurization decreased osmolarity by 20-30 mOsm/L (P < 0.001), and storage for 24 hours slightly increased osmolarity (by 11.5 mOsm/L P = 0.0002). Therapeutic additives increased osmolarity up to 868 mOsm/L.

CONCLUSIONS

Adding HM fortifier and additional protein to HM increased osmolarity to >400 mOsm/L and therefore above the recommended threshold. Because of the excessive increase in osmolarity combinations of HM + fortifier and additional protein should not be applied together with multivitamins or other additives.

Donor human milk banking and the emergence of milk sharing

Donor human milk has emerged as the preferred substrate to feed extremely preterm infants, when mother's own milk is unavailable. This article summarizes the clinical data demonstrating the safety, efficacy, and cost-effectiveness of feeding donor human milk to premature babies. It describes the current state of milk banking in North America, as well as other parts of the world, and the differing criteria for donor selection, current pasteurization techniques, and quality control measures. A risk assessment methodology is proposed, which would allow milk banks globally to assess the safety of their process and respond appropriately to differing risk environments.

Infant feeding and transmission of human immunodeficiency virus in the United States

Physicians caring for infants born to women infected with HIV are likely to be involved in providing guidance to HIV-infected mothers on appropriate infant feeding practices. It is critical that physicians are aware of the HIV transmission risk from human milk and the current recommendations for feeding HIV-exposed infants in the United States. Because the only intervention to completely prevent HIV transmission via human milk is not to breastfeed, in the United States, where clean water and affordable replacement feeding are available, the American Academy of Pediatrics recommends that HIV-infected mothers not breastfeed their infants, regardless of maternal viral load and antiretroviral therapy.

HIV-1 and breastfeeding: biology of transmission and advances in prevention

Breastfeeding accounts for about 40% of mother-to-child transmission of HIV-1 worldwide and carries an estimated risk of transmission of 0.9% per month after the first month of breastfeeding. It is recommended that HIV-1-infected women completely avoid breastfeeding in settings where safe feeding alternatives exist. However, as replacement feeding is not safely available in many parts of the world, and because breastfeeding provides optimal nutrition and protection against other infant infections, there is intense ongoing research to make breastfeeding safe for HIV-1-infected mothers in resource-limited settings. More research is needed to determine the optimal duration of breastfeeding, optimal weaning practices, and which individual antiretroviral prophylactic regimen is best for HIV-1-infected mothers and their infants in a particular setting.

Human milk banking-facts and issues to resolve

The number of human milk banks is increasing worldwide. Although the beneficial effects of feeding premature infants with their mother’s milk are well documented, less is known about the effects of feeding these infants with pasteurized donor milk. We propose a randomized trial comparing the effects of a 100% human milk-based diet (human milk supplemented with a human milk-derived fortifier) and a diet (partially) based on bovine milk. In theory, human milk has a beneficial effect on various aspects of human physiology, most of which become apparent after infancy. We therefore propose an extensive follow-up program that takes this aspect into consideration. Other issues concerning the practice of human milk banks need to be addressed as well as optimization of the feeding strategies for preterm infants.

Breastfeeding in HIV-positive women: What can be recommended?

Breastfeeding remains a common practice in parts of the world where the burden of HIV is highest and the fewest alternative feeding options exist. The impossible dilemma faced by HIV-positive mothers is whether to breastfeed their infants in keeping with cultural norms but in doing so risk transmitting the virus through breast milk, or to pursue formula feeding, which comes with its own set of risks, including a higher rate of infant mortality from diarrheal illnesses, while reducing transmission of HIV. Treatment of mothers and/or their infants with antiretroviral drugs is a strategy that has been employed for several decades to reduce HIV transmission through pregnancy and delivery, but the effect of these agents when taken during breastfeeding is a newer field of study. In this article we evaluate the latest clinical research, from trials that encourage exclusive breastfeeding to trials of antiretroviral therapy (ART) for either the mother or infant, in an attempt to prevent transmission of HIV through breast milk. Additionally, we discuss research that is in progress, with results anticipated in the next few years that will further shape clinical guidelines and practice. Exclusive breastfeeding is much safer than mixed feeding (the supplementation of breastfeeding with other foods), and should be encouraged even in settings where ART for either the mother or infant is not readily available. The research published regarding maternal treatment with highly active antiretroviral therapy (HAART) during pregnancy and the breastfeeding period has all been non-randomized with relatively little statistical power, but suggests maternal HAART can drastically reduce the risk of transmission of HIV. Infant prophylaxis has been intensively studied in several trials and has been shown to be as effective as maternal treatment with antiretrovirals, reducing the transmission rate after 6 weeks to as low as 1.2%. Research that is in progress will provide us with more answers about the relative contribution of maternal treatment and infant prophylaxis in preventing transmission, and the results of such research may be expected as early as this year through 2013. There is hope that perinatal HIV transmission may be greatly reduced in breastfeeding populations worldwide through a combination of behavioral interventions that encourage exclusive breastfeeding and pharmacologic interventions with antiretrovirals for mothers and/or their infants.

Pasteurization of mother's own milk reduces fat absorption and growth in preterm infants

AIM

A randomized study was conducted to evaluate whether pasteurized milk (Holder pasteurization 62.5 degrees C, 30 min) reduces fat absorption and growth in preterm infants.

METHODS

Preterm infants (825-1325 g) born with gestational age < or =30 weeks were randomized into two groups, of which one started with pasteurized own mother's milk for 1 week and continued with raw milk the following week, and a second group was fed in reverse order. By using this design the infants served as their own controls. At the end of each week, a 72-h fat balance was performed and growth was monitored.

RESULTS

We found, on an average, 17% higher fat absorption with raw as compared to pasteurized milk. Infants gained more weight and linear growth assessed as knee-heel length was also greater during the week they were fed raw milk as compared to the week they were fed pasteurized milk.

CONCLUSION

Feeding preterm infants pasteurized as compared to raw own mother's milk reduced fat absorption. When the infants were fed raw milk, they gained more in knee-heel length compared to when they were fed pasteurized milk.

Flash-heat inactivation of HIV-1 in human milk: a potential method to reduce postnatal transmission in developing countries

BACKGROUND

Up to 40% of all mother-to-child transmission of HIV occurs by means of breast-feeding; yet, in developing countries, infant formula may not be a safe option. The World Health Organization recommends heat-treated breast milk as an infant-feeding alternative. We investigated the ability of a simple method, flash-heat, to inactivate HIV in breast milk from HIV-positive mothers.

METHODS

Ninety-eight breast milk samples, collected from 84 HIV-positive mothers in a periurban settlement in South Africa, were aliquoted to unheated control and flash-heating. Reverse transcriptase (RT) assays (lower detection limit of 400 HIV copies/mL) were performed to differentiate active versus inactivated cell-free HIV in unheated and flash-heated samples.

RESULTS

We found detectable HIV in breast milk samples from 31% (26 of 84) of mothers. After adjusting for covariates, multivariate logistic regression showed a statistically significant negative association between detectable virus in breast milk and maternal CD4+ T-lymphocyte count (P=0.045) and volume of breast milk expressed (P=0.01) and a positive association with use of multivitamins (P=0.03). All flash-heated samples showed undetectable levels of cell-free HIV-1 as detected by the RT assay (P<0.00001).

CONCLUSIONS

Flash-heat can inactivate HIV in naturally infected breast milk from HIV-positive women. Field studies are urgently needed to determine the feasibility of in-home flash-heating breast milk to improve infant health while reducing postnatal transmission of HIV in developing countries.

Prevention of human immunodeficiency virus-1 transmission to the infant through breastfeeding: new developments

Breastfeeding accounts for up to half of all infant human immunodeficiency virus (HIV) infections worldwide and carries an estimated transmission risk of about 15% when continued into the second year of life. Because replacement feeding is not safely available, culturally acceptable, or affordable in many parts of the world and because breastfeeding provides protection against other causes of infant mortality, approaches that reduce breastfeeding mother-to child transmission of HIV are being explored. These include exclusive breastfeeding for the infant's first few months of life followed by rapid weaning, treatments of expressed milk to inactivate the virus, and antiretroviral prophylaxis taken by the infant or mother during breastfeeding, which are strategies currently being tested in clinical trials. Passive (antibodies) and active (vaccine) immunoprophylaxis will also soon begin to be tested. This paper focuses on current and planned research on strategies to prevent breastfeeding transmission of HIV.

Hiv-specific secretory IgA in breast milk of HIV-positive mothers is not associated with protection against HIV transmission among breast-fed infants

OBJECTIVES

To test whether secretory immunoglobulin A (sIgA) to human immunodeficiency virus (HIV) antigens in breast milk of HIV-positive women is associated with protection against HIV transmission among breast-fed infants.

STUDY DESIGN

Nested, case-control design in which HIV-specific sIgA was measured in breast milk collected from 90 HIV-positive women enrolled in a study in Lusaka, Zambia. Milk samples were selected to include 26 HIV-positive mothers with infected infants (transmitters) and 64 mothers with uninfected infants (nontransmitters).

RESULTS

HIV-specific sIgA was detected more often in breast milk of transmitting mothers (76.9%) than in breast milk of nontransmitting mothers (46.9%, P = .009). There were no significant associations between HIV-specific sIgA in breast milk and other maternal factors, including HIV RNA quantities in breast milk, CD4 count, and plasma RNA quantities.

CONCLUSIONS

HIV-specific sIgA in breast milk does not appear to be a protective factor against HIV transmission among breast-fed infants.

Comparison of human immunodeficiency virus type 1-specific inhibitory activities in saliva and other human mucosal fluids

Several human mucosal fluids are known to possess an innate ability to inhibit human immunodeficiency virus type 1 (HIV-1) infection and replication in vitro. This study compared the HIV-1 inhibitory activities of several mucosal fluids, whole, submandibular/sublingual (sm/sl), and parotid saliva, breast milk, colostrum, seminal plasma, and cervicovaginal secretions, from HIV-1-seronegative donors by using a 3-day microtiter infection assay. A wide range of HIV-1 inhibitory activity was exhibited in all mucosal fluids tested, with some donors exhibiting high levels of activity while others showed significantly lower levels. Colostrum, whole milk, and whole saliva possessed the highest levels of anti-HIV-1 activity, seminal fluid, cervicovaginal secretions, and sm/sl exhibited moderate levels, and parotid saliva consistently demonstrated the lowest levels of HIV-1 inhibition. Fast protein liquid chromatography gel filtration studies revealed the presence of at least three distinct peaks of inhibitory activity against HIV-1 in saliva and breast milk. Incubation of unfractionated and fractionated whole saliva with antibodies raised against human lactoferrin (hLf), secretory leukocyte protease inhibitor (SLPI), and, to a lesser extent, MG2 (high-molecular-weight mucinous glycoprotein) reduced the HIV-1 inhibitory activity significantly. The results suggest that hLf and SLPI are two key components responsible for HIV-1 inhibitory activity in different mucosal secretions. The variation in HIV inhibitory activity between the fluids and between individuals suggests that there may be major differences in susceptibility to HIV infection depending both on the individual and on the mucosal fluid involved.

Acceptability of heat treating breast milk to prevent mother-to-child transmission of human immunodeficiency virus in Zimbabwe: a qualitative study

Although heat treatment of human milk is an official infant-feeding recommendation for human immunodeficiency virus (HIV)-positive mothers in Zimbabwe, its implementation has not been adequately addressed, because knowledge about the safety of this method is rudimentary and its acceptability is poorly understood. To address this knowledge gap, the authors conducted focus group discussions among mothers, grandmothers, midwives, and husbands in various regions of Zimbabwe. Although the practice of heat treating expressed human milk was initially met with skepticism because of potential obstacles, including time constraints and social and cultural stigma, a pattern of opinion reversal emerged in all groups. By the end of each discussion, participants believed that, given its affordability and its potential to protect infants from HIV infection, heat-treated human milk may be a feasible infant-feeding option for HIV-positive mothers in Zimbabwe. These findings merit further investigation so that appropriate behavioral strategies can be designed.

Biochemical analysis of human milk treated with sodium dodecyl sulfate, an alkyl sulfate microbicide that inactivates human immunodeficiency virus type 1

Reduction of transmission of human immunodeficiency virus type 1 (HIV-1) through human milk is needed. Alkyl sulfates such as sodium dodecyl sulfate (SDS) are microbicidal against HIV-1 at low concentrations, have little to no toxicity, and are inexpensive. The authors have reported that treatment of HIV-1-infected human milk with < or = 1% (10 mg/mL) SDS for 10 minutes inactivates cell-free and cell-associated virus. The SDS can be removed with a commercially available resin after treatment without recovery of viral infectivity. In this article, the authors report results of selective biochemical analyses (ie, protein, immunoglobulins, lipids, cells, and electrolytes) of human milk subjected to SDS treatment and removal. The SDS treatment or removal had no significant effects on the milk components studied. Therefore, the use of alkyl sulfate microbicides to treat milk from HIV-1-positive women may be a simple, practical, and nutritionally sound way to prevent or reduce transmission of HIV-1 while still feeding with mother's own milk.

Alternative modified infant-feeding practices to prevent postnatal transmission of human immunodeficiency virus type 1 through breast milk: past, present, and future

Preventing mother-to-child transmission (MTCT) of human immunodeficiency virus type 1 (HIV-1) through breastfeeding is important to reduce the number of infected children. Research on making breastfeeding safer is a high priority. The authors reviewed the attempts to develop alternative methods, other than antiretroviral (ARV) therapy of mothers and/or babies, to decontaminate breast milk of infectious HIV-1 (free and associated with lymphocytes). They also review how these methods affect milk constituents, as well as their current and prospective status. A PubMed search for English publications on methods to prevent MTCT through breast milk was completed. Methods that have been tested, other than systemicuse or ARV or immunoprophylaxis, to reduce or prevent MTCT of HIV-1 through breast milk were broadly classified into 5 groups: (1) modified feeding practices, (2) heat treatment of milk, (3) lipolysis, (4) antimicrobial treatment of the breastfeeding mother, and (5) microbicidal treatment of infected milk. Their advantages and disadvantages are discussed, as well as future directions in the prevention of MTCT through breastfeeding.

Viral, Nutritional, and Bacterial Safety of Flash-Heated and Pretoria-Pasteurized Breast Milk to Prevent Mother-to-Child Transmission of HIV in Resource-Poor Countries

BACKGROUND

Heat-treated breast milk of HIV-positive mothers has potential to reduce vertical transmission. This study compared the impact of flash-heating (FH) and Pretoria pasteurization (PP) on HIV, nutrients, and antimicrobial properties in human milk.

METHODS

Milk samples were spiked with 1 x 10 (8) copies/mL of clade C HIV-1 and treated with FH and PP. We measured HIV reverse transcriptase (RT) activity before and after heating (n = 5). Heat impact on vitamins A, B6, B12, and C; folate, riboflavin, thiamin, and antimicrobial proteins (lactoferrin and lysozyme) was assessed. Storage safety was evaluated by spiking with Escherichia coli or Staphylococcus aureus.

RESULTS

Both methods inactivated > or = 3 logs of HIV-1. FH resulted in undetectable RT activity. Neither method caused significant decrease in any vitamin, although reductions in vitamins C and E were noted. Heat decreased immunoreactive lactoferrin (P < 0.05) but not the proportions of lactoferrin and lysozyme surviving digestion. FH seems to retain more antibacterial activity. Both treatments eliminated spiked bacteria.

CONCLUSIONS

FH may be superior to PP in eliminating all viral activity; both methods retained nutrients and destroyed bacterial contamination. Heat-treated breast milk merits further study as a safe and practical infant feeding option for HIV-positive mothers in developing countries.

Inactivation of HIV-1 in breast milk by treatment with the alkyl sulfate microbicide sodium dodecyl sulfate (SDS)

BACKGROUND

Reducing transmission of HIV-1 through breast milk is needed to help decrease the burden of pediatric HIV/AIDS in society. We have previously reported that alkyl sulfates (i.e., sodium dodecyl sulfate, SDS) are microbicidal against HIV-1 at low concentrations, are biodegradable, have little/no toxicity and are inexpensive. Therefore, they may be used for treatment of HIV-1 infected breast milk. In this report, human milk was artificially infected by adding to it HIV-1 (cell-free or cell-associated) and treated with

RESULTS

SDS (>or=0.1%) was virucidal against cell-free and cell-associated HIV-1 in breast milk. SDS could be substantially removed from breast milk, without recovery of viral infectivity. Viral load in artificially infected milk was reduced to undetectable levels after treatment with 0.1% SDS. SDS was virucidal against HIV-1 in human milk and could be removed from breast milk if necessary. Milk was not infectious after SDS removal.

CONCLUSION

The proposed treatment concentrations are within reported safe limits for ingestion of SDS by children of 1 g/kg/day. Therefore, use of alkyl sulfate microbicides, such as SDS, to treat HIV1-infected breast milk may be a novel alternative to help prevent/reduce transmission of HIV-1 through breastfeeding.

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Key Words Collapse

MESH Headings

• Adult
• Anti-HIV Agents/pharmacology
• CD4 Antigens/metabolism
• Cell Line
• Female
• HIV Infections/transmission
• HIV Infections/virology
• HIV-1/drug effects
• HIV-1/pathogenicity
• HeLa Cells
• Humans
• Infectious Disease Transmission, Vertical/prevention & control
• Milk, Human/drug effects
• Milk, Human/virology
• Sodium Dodecyl Sulfate/pharmacology
• Surface-Active Agents/pharmacology
• T-Lymphocytes/virology

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Grants

• F32 HD041346 NICHD NIH HHS
• F32 HD41346 NICHD NIH HHS
• P01 AI37829 NIAID NIH HHS

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Affiliation(s)

Sandra Urdaneta Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania 17033 USA Department of Bioscience and Biotechnology, Drexel University, College of Medicine, Philadelphia, Pennsylvania 19104 USA
Brian Wigdahl Department of Microbiology and Immunology, Institute for Molecular Medicine and Infectious Diseases, Drexel University, College of Medicine, Philadelphia, Pennsylvania 19104 USA
Elizabeth B Neely Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania 17033 USA Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, Pennsylvania 17033 USA
Cheston M Berlin Department of Pediatrics, Penn State College of Medicine, Hershey, Pennsylvania 17033 USA Department of Pharmacology, Penn State College of Medicine, Hershey, Pennsylvania 17033 USA
Cara-Lynne Schengrund Department of Biochemistry, Penn State College of Medicine, Hershey, Pennsylvania 17033 USA
Hung-Mo Lin Department of Health Evaluation Sciences, Penn State College of Medicine, Hershey, Pennsylvania 17033 USA
Mary K Howett Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania 17033 USA Department of Bioscience and Biotechnology, Drexel University, College of Medicine, Philadelphia, Pennsylvania 19104 USA

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Preventing postnatal transmission of HIV-1 through breast-feeding: modifying infant feeding practices

Approaches to reducing or preventing the risk of postnatal transmission through breast-feeding include the avoidance of all breast-feeding and the use of exclusive replacement feeds or exclusive breast-feeding for a limited duration with early and rapid cessation of breast-feeding around 4-6 months of age. The efficacy and safety of the latter approach have not been established and studies are in progress to provide further information. In addition, inactivation of HIV in breast milk would allow breast-feeding to continue while reducing the risk of postnatal transmission of HIV and may be usefully applied in certain circumstances, such as for premature infants or while a mother recovers from mastitis. In this review, experience is reported from clinical trials or studies additional to their main objective of assessing rates and risk factors for mother-to-child transmission. This may inform policy, programming, and training options and may be especially valuable in the absence of conclusive data on the efficacy of the interventions to be applied during the breast-feeding period.

Humans have antibodies reactive with Bovine leukemia virus

Bovine leukemia virus (BLV) is an oncogenic retrovirus that commonly infects cattle and causes B cell leukosis in 1-5% of infected cattle. BLV-infected cells are present in marketed beef and dairy products. In the decade after the discovery of BLV in 1969, studies using agar gel immunodiffusion and complement fixation assays failed to find antibodies to BLV in human sera. This led to the prevailing opinion that exposure of humans to BLV and/or the potential for infection are not significant and therefore the virus is not a public health hazard. We reexamined this issue using more sensitive immunological techniques available today. Using immunoblotting to test the sera of 257 humans for antibodies of four isotypes (IgG1, IgM, IgA, and IgG4) to the BLV capsid antigen (p24), we detected at least one antibody isotype reactive with BLV in 74% of the human sera tested. The specificity of the reactivity was strongly suggested by competition studies and by ruling out cross-reacting antibodies to other chronic human viruses. Our results suggest that antibodies reactive with the BLV capsid antigen may serve as a biomarker for exposure to BLV and this exposure may be widespread. The results do not necessarily mean that humans are actually infected with BLV; the antibodies could be a response to heat-denatured BLV antigens consumed in food. They do, however, suggest that further studies in this area could be important.

Human milk, breastfeeding, and transmission of human immunodeficiency virus type 1 in the United States. American Academy of Pediatrics Committee on Pediatric AIDS

Transmission of human immunodeficiency virus type 1 (HIV-1) through breastfeeding has been conclusively demonstrated. The risk of such transmission has been quantified, the timing has been clarified, and certain risk factors for breastfeeding transmission have been identified. In areas where infant formula is accessible, affordable, safe, and sustainable, avoidance of breastfeeding has represented one of the main components of mother-to-child HIV-1 transmission prevention efforts for many years. In areas where affordable and safe alternatives to breastfeeding may not be available, interventions to prevent breastfeeding transmission are being investigated. Complete avoidance of breastfeeding by HIV-1-infected women has been recommended by the American Academy of Pediatrics and the Centers for Disease Control and Prevention and remains the only means by which prevention of breastfeeding transmission of HIV-1 can be absolutely ensured. This technical report summarizes the information available regarding breastfeeding transmission of HIV-1.

HIV transmission through breastfeeding: problems and prevention

The greatest burden of HIV infection in women and their children is disproportionately borne by the poorest countries, especially in sub-Saharan Africa. Breastfeeding is a major health-promoting factor for infants and children in developing countries but the risk of mother-to-child transmission (MTCT) of HIV by this route is challenging traditional practices and health policies in low-resource countries. Maternal and infant factors contributing to the risk of MTCT through breastfeeding are still poorly understood and not well researched. Factors identified include: advanced clinical stages of infection in the mother; high maternal plasma HIV-1 load; presence of mastitis; and infant oral thrush. In many developing countries, international agencies are providing support and recommendations for preventing MTCT of HIV-1 by breastfeeding. Preventive strategies supported by WHO/UNICEF and charitable agencies in some sentinel centres in sub-Saharan Africa include routine antenatal voluntary counselling and testing (VCT), PCR testing of infants of seropositive mothers at 6 weeks of age, various combinations of a shortened period (3-6 mths) of exclusive breastfeeding, perinatal administration of antiretrovirals (ARV) such as nevirapine and provision of affordable and safe infant replacement feeds (presently given free by UNICEF in some centres). Many problems, however, have hindered effective implementation of these interventions. In many poor communities, even where VCT facilities are available, acceptance of HIV testing is low because there is fear of stigmatisation by the spouse, family or community and compliance with complex drug regimens is therefore poor. Other problems include the exorbitant cost of antiretroviral drugs, inadequately resourced health care systems and unavailability or poor acceptance of safe breast-milk alternatives. The rate of mixed feeding is high and so the risk of MTCT is increased. Continued promotion of exclusive breastfeeding for at least 6 months, irrespective of HIV status, followed by a properly prepared, high energy, nutritious complementary diet, with the possibility of early weaning to an animal milk formula, still appears to be the most appropriate option for the poor in countries with high levels of MTCT not deriving any benefit from the above strategies. While a longer period of breastfeeding would probably increase the risk of MTCT in vulnerable communities, a shorter duration would certainly increase infant morbidity and mortality. Results of investigations of the efficacy of ARV for protecting the infants of HIV-infected mothers during the breastfeeding period are awaited.

Trends in donor milk banking in the United States

Modern donor milk banking was conceived in the US in the early 1900s as a medicalized version of wet nursing. Over the course of the century the fortunes of donor milk banking have varied considerably. In the last 20 years donor milk banking has been negatively affected by the development of specialty formulas, safety issues related to viral transmission, and lack of clinical research. To survive, US milk banks have been receptive to clinical uses considered as "alternative medicine," and have cooperated with governmental agencies to develop standards for safety. A qualitative analysis of collected case histories of US donor milk recipients demonstrates that donor human milk banking can be critical to survival and the well-being of at-risk infants, children, and the occasional adult. By analyzing national data collected by survey method and examining the literature, the researcher compared German and US milk banks and distribution data. German milk banks use donor milk exclusively for premature infants and have less stringent operating standards, yet dispense volumes of milk greatly in excess of the US milk banks. While statistics are lacking for the total recipient population in the US, a projected analysis (based on German consumption) of the potential volume that could be dispensed in the US is presented, indicating that the population in need of this crucial public health service is currently under-served in the US.

Donor human milk for preterm infants

As survival rates for preterm infants improve, more attention is being focused on improving the quality of survival through optimal nutritional management. The benefits of human milk for term infants are well recognized, with current research suggesting that human milk may especially benefit the preterm infant. Some mothers are unable or unwilling to provide breastmilk for their infants. Although not as well studied as mother's own milk, pasteurized donor human milk can provide many of the components and benefits of human milk while eliminating the risk of transmission of infectious agents. Pasteurization does affect some of the nutritional and immunologic components of human milk, but many immunoglobulins, enzymes, hormones, and growth factors are unchanged or minimally decreased. In California donor human milk costs approximately $3.00 per ounce to purchase. A reduction in length of stay, necrotizing enterocolitis and sepsis may result in a relative saving of approximately $11 to the NICU or healthcare plan for each $1 spent for pasteurized donor milk.

Donor milk: what's in it and what's not

Breastfeeding and human milk are widely recognized as optimal for human infants. However, if donor milk is used when mother's own milk is not available, some questions arise concerning the effects of storage, handling, and heat processing on the unique components of human milk. Holder pasteurization (62.5 degrees C for 30 minutes) of banked human milk is the method of choice to eliminate potential viral contaminants such as human immunodeficiency virus, human T-lymphoma virus, and cytomegalovirus, as well as tuberculosis and other bacterial contaminants, while maintaining the greatest possible complement of its unique bioactive factors. This article reviews some of the critical components of human milk and what is currently known about the effects of Holder pasteurization on their biological activity.

Effects of lipolysis or heat treatment on HIV-1 provirus in breast milk

BACKGROUND

Transmission of HIV-1 infection through breastfeeding is associated with integrated DNA (provirus) in milk cells. Reduction of HIV-1 DNA in milk may lessen infectivity.

PURPOSE

To investigate efficacy of two methods available in developing countries to reduce HIV-1 proviral DNA in breast milk.

METHODS

Methods simulated field conditions; milk was heated by bringing it to a boil, for instance, over a cooking fire, and lipolysis was done at room temperature. Four HIV-positive pregnant women were recruited for this pilot study, instructed to feed formula exclusively, and to stimulate milk production using pumping. Milk was collected twice weekly for 3 weeks and analyzed qualitatively for HIV-1 proviral DNA by polymerase chain reaction at three stages: 1) fresh, 2) after standing for 6 hours, and 3) after having been brought to the boiling point.

RESULTS

Seventeen samples from 4 mothers were analyzed. Fifteen of 17 fresh samples (88%) had measurable HIV-1 proviral DNA despite all mothers' having had low or undetectable plasma viral loads. Lipolysis (standing at room temperature) for 6 hours did not destroy proviral DNA: 6 of 7 samples (86%) tested positive for DNA after lipolysis. No samples of milk (n = 8) brought to a boil were positive for HIV-1 proviral DNA (p <.0001).

CONCLUSIONS

This preliminary evidence suggests that inherent lipolytic activity of fresh breast milk is inadequate for destruction of HIV-1; bringing breast milk to a boil may result in decreased HIV-1 infectivity; and breast milk cell-associated HIV-1 may not reflect plasma viral load. Nutritional value or possible bacterial contamination of milk treated in this manner was not assessed.