Breast Milk from Tanzanian Women has Divergent Effects on Cell-Free and Cell-Associated HIV-1 Infection in Vitro.

Transmission of HIV-1 during breastfeeding is a significant source of new pediatric infections in sub-Saharan Africa. Breast milk from HIV-positive mothers contains both cell-free and cell-associated virus; however, the impact of breast milk on HIV-1 infectivity remains poorly understood. In the present study, breast milk was collected from HIV-positive and HIV-negative Tanzanian women attending antenatal clinics in Dar es Salaam. Milk was analyzed for activity in vitro against both cell-free and cell-associated HIV-1. Potent inhibition of cell-free R5 and X4 HIV-1 occurred in the presence of milk from all donors regardless of HIV-1 serostatus. Inhibition of cell-free HIV-1 infection positively correlated with milk levels of sialyl-Lewis(X) from HIV-positive donors. In contrast, milk from 8 of 16 subjects enhanced infection with cell-associated HIV-1 regardless of donor serostatus. Milk from two of these subjects contained high levels of multiple pro-inflammatory cytokines including TNFα, IL-1β, IL-6, IL-8, MIP-1α, MIP-1β, MCP-1 and IP-10, and enhanced cell-associated HIV-1 infection at dilutions as high as 1∶500. These findings indicate that breast milk contains innate factors with divergent activity against cell-free and cell-associated HIV-1 in vitro. Enhancement of cell-associated HIV-1 infection by breast milk may be associated with inflammatory conditions in the mother and may contribute to infant infection during breastfeeding

Enhancement of cell-associated HIV-1 infection by breast milk.

<p>Breast milk from HIV-positive and HIV-negative donors was evaluated for activity against cell-associated HIV-1 infection in TZM-bl cell assays. Breast milk was tested at 5-fold serial dilutions (1∶4, 1∶20, 1∶100 and 1∶500). Percent inhibition or enhancement of cell-associated R5 HIV-1_BAL is shown for breast milk samples from individual HIV-positive (open circles) and HIV-negative (closed circles) donors.</p

Immune factors in breast milk from Tanzanian donors.

<p>The concentrations of multiple immune factors including cytokines, chemokines and growth factors were measured in breast milk samples using a multiplex panel. Data for each factor is expressed as concentration (pg/mL) and is presented for all donors irrespective of HIV serostatus.</p

Characteristics of Tanzanian breast milk donors.

<p>Characteristics of Tanzanian breast milk donors.</p

Inhibition of cell-free HIV-1 by breast milk.

<p>Mature breast milk from HIV-positive (n = 8) and HIV-negative (n = 8) donors was evaluated for inhibition of cell-free HIV-1 in TZM-bl cell assays. Cells were infected with R5 HIV-1_BaL in the presence of five-fold serial dilutions of breast milk. Percent inhibition was calculated relative to control cultures infected with HIV-1_BaL in the absence of added breast milk. HIV-inhibitory activity of breast milk from HIV-positive (dotted line) and HIV-negative (solid line) donors is shown (mean ± SD).</p

Lewis^X and sialyl-Lewis^X in breast milk.

<p>Levels of Lewis^X and sialyl-Lewis^X were measured by ELISA in breast milk samples from both HIV-positive and HIV-negative donors. The results were then compared to cell-free HIV-inhibitory activity for the same samples. Data is expressed as the percent inhibition of cell-free R5 (□) and X4 (♦) HIV-1 relative to the levels of either Lewis^X or sialyl-Lewis^X measured for each sample.</p

Fetal exposures and perinatal influences on the stool microbiota of premature infants

<div><p></p><p><i>Objective</i>: To test the hypothesis that maternal complications significantly affect gut colonization patterns in very low birth weight infants.</p><p><i>Methods</i>: Forty-nine serial stool samples were obtained weekly from nine extremely premature infants enrolled in a prospective longitudinal study. Sequencing of the bacterial 16S rRNA gene from stool samples was performed to approximate the intestinal microbiome. Linear mixed effects models were used to evaluate relationships between perinatal complications and intestinal microbiome development.</p><p><i>Results</i>: Subjects with prenatal exposure to a non-sterile intrauterine environment, i.e. prolonged preterm premature rupture of membranes (PPPROM) and chorioamnionitis exposure, were found to have a relatively higher abundance of potentially pathogenic bacteria in the stool across all time points compared to subjects without those exposures, irrespective of exposure to postnatal antibiotics. Compared with those delivered by Caesarean section, vaginally delivered subjects were found to have significantly lower diversity of stool microbiota across all time points, with lower abundance of many genera, most in the family <i>Enterobacteriaceae</i>.</p><p><i>Conclusions</i>: We identified persistently increased potential pathogen abundance in the developing stool microbiota of subjects exposed to a non-sterile uterine environment. Maternal complications appear to significantly influence the diversity and bacterial composition of the stool microbiota of premature infants, with findings persisting over time.</p></div

Fetal exposures and perinatal influences on the stool microbiota of premature infants

<div><p></p><p><i>Objective</i>: To test the hypothesis that maternal complications significantly affect gut colonization patterns in very low birth weight infants.</p><p><i>Methods</i>: Forty-nine serial stool samples were obtained weekly from nine extremely premature infants enrolled in a prospective longitudinal study. Sequencing of the bacterial 16S rRNA gene from stool samples was performed to approximate the intestinal microbiome. Linear mixed effects models were used to evaluate relationships between perinatal complications and intestinal microbiome development.</p><p><i>Results</i>: Subjects with prenatal exposure to a non-sterile intrauterine environment, i.e. prolonged preterm premature rupture of membranes (PPPROM) and chorioamnionitis exposure, were found to have a relatively higher abundance of potentially pathogenic bacteria in the stool across all time points compared to subjects without those exposures, irrespective of exposure to postnatal antibiotics. Compared with those delivered by Caesarean section, vaginally delivered subjects were found to have significantly lower diversity of stool microbiota across all time points, with lower abundance of many genera, most in the family <i>Enterobacteriaceae</i>.</p><p><i>Conclusions</i>: We identified persistently increased potential pathogen abundance in the developing stool microbiota of subjects exposed to a non-sterile uterine environment. Maternal complications appear to significantly influence the diversity and bacterial composition of the stool microbiota of premature infants, with findings persisting over time.</p></div

Sialic acid levels in breast milk from HIV-positive Tanzanian women and impact of maternal diet.

OBJECTIVE: To quantify total sialic acid in milk from HIV-positive Tanzanian mothers and to determine the impact of maternal diet on milk sialic acid levels. DESIGN: Milk samples were analyzed from 74 HIV-positive, Tanzanian women enrolled in a randomized, controlled clinical study of a dietary macronutrient supplement. Women were provided with a daily protein-calorie supplement and a micronutrient supplement or micronutrient supplement only during the last trimester of pregnancy and up to the first 6 months of breastfeeding. METHODS: Milk samples were collected at approximately 2 weeks and at least 3 months postpartum and assayed for total sialic acid. Milk sialic acid was assessed relative to maternal macronutrient intake, age, BMI, CD4+ cell count and infant birth weight. RESULTS: The mean concentration of milk sialic acid was highest in the first 2 weeks postpartum (6.89 ± 2.79 mmol/l) and declined rapidly by 3 months (2.49 ± 0.60 mmol/l). Sialic acid content in milk was similar between both treatment arms of the study, and did not correlate with maternal macronutrient intake. No correlation was found between maternal age, BMI, CD4+ cell count or infant birth weight and total milk sialic acid concentration. CONCLUSION: Milk sialic acid levels in HIV-positive, Tanzanian women without malnutrition are comparable with reported values for women of European descent and show a similar temporal decline during early lactation. These findings suggest that total milk sialic acid is maintained despite macronutrient deficiencies in maternal diet and support a conserved role for milk sialic acid in neonatal development