Human Milk Retains Important Immunologic Properties After Defatting.

BACKGROUND: In neonatal chylothorax, thoracic lymphatic drainage is ineffective. The resultant effusions often require drainage, leading to a loss of immune components. Affected infants can be managed with formula or defatted human milk feedings low in long-chain triglycerides to decrease lymph production. We hypothesized that there is no significant difference in the immunological profile or antibacterial effect of full-fat and defatted human milk. METHODS: Milk from lactating mothers was divided into 1 aliquot that was defatted via centrifugation with the full-fat aliquot as control. Macronutrient content was analyzed with mid-infrared spectroscopy. Flow cytometry was used to measure immune cell populations. Lactoferrin, lysozyme, immunoglobulin (Ig)A, and IgG values were determined using enzyme-linked immunosorbent assay. The antibacterial properties were determined by inoculating paired full-fat and defatted milk samples with Escherichia coli or Streptococcus pneumoniae bacteria and performing colony counts. RESULTS: Compared with full-fat milk, defatted milk demonstrated decreased total energy and fat and increased carbohydrate concentrations. Defatted milk demonstrated a significant decrease in all immune cell populations. There was no difference in IgA, IgG, lysozyme, or lactoferrin concentrations. Both aliquots demonstrated equivalent growth inhibition of E. coli and S. pneumoniae. CONCLUSIONS: Unexpectedly, defatted human milk contained significantly less leukocytes than full-fat milk. IgA, IgG, lysozyme, and lactoferrin concentrations were preserved. The ability of defatted milk to inhibit bacterial growth was unaffected, suggesting that the antibacterial benefits of human milk remain after the defatting process. Further investigation regarding the clinical effect of leukocyte loss in defatted milk is warranted.

Interchanging Breast Pump Kit Brands Alters Breast Pump Suction Pressure.

Background: Postpartum mothers express and store breast milk using a hospital-grade pump and manufacturer-specific kit (flanges, bottles, tubing, valves, and membranes). After hospital discharge, mothers may attempt to interchange kits from different manufacturers. The objective of this study is to determine whether pump performance is affected by the use of a different manufacturer's kit. Materials and Methods: Suction pressure was tested using kits and six pumps from three manufacturers (Ameda, Medela, and Spectra). Pump settings (speed and vacuum strength) simulated maximum, minimum, and commonly used median settings. Suction pressure (mmHg) was measured using an analog gauge and repeated six times for each pump-kit combination. Measurements were compared using repeated measures analysis of covariance (ANCOVA) to determine whether kit was an independent predictor of suction pressure. Results: The kit type was a significant independent predictor (p < 0.05) of suction pressure for all at medium vacuum strength and many at maximum and minimum vacuum strengths. Upon further analysis interchanging kits resulted in both significantly increased and decreased suction pressures compared to the manufacturer-specific kit. Conclusion: Breast pump kits generate variable suction pressures when interchanged between pumps from different manufacturers. Interchanging combinations of kits and breast pumps could potentially lead to low milk expression due to ineffective suction pressure or increased discomfort from excessive pressure. The results of this study emphasize the importance of maternal education regarding the use of manufacturer-specific kits and breast pumps.