The Influence of Holder Pasteurization on the Diversity of the Human Milk Bacterial Microbiota Using High-Throughput DNA Sequencing.

BACKGROUND: Human milk is the best food for infants; however, when breastfeeding is not possible, pasteurized milk from human milk banks is the best alternative. Little has been reported about variations in the bacterial microbiota composition of human milk after pasteurization. RESEARCH AIM: To characterize and compare the bacterial microbiota composition and diversity within human milk among Mexican mothers before and after the Holder pasteurization process. METHODS: A cross-sectional, observational, and comparative design was used. The effect of the pasteurization process on the bacterial composition and diversity of human milk samples of donors (N = 42) from a public milk bank was assessed before and after pasteurization by high throughput deoxyribonucleic acid sequencing of V3-16S rRNA gene libraries. Sequencing data were examined using the Quantitative Insights into Microbial Ecology software and Phyloseq in R environment. RESULTS: A varied community of bacteria was found in both raw and pasteurized human milk. The bacterial diversity of the milk samples was increased by the pasteurization, where some thermoduric bacteria of the phyla Proteobacteria, Firmicutes, and Actinobacteria were more abundant. The source tracker analysis indicated that at most 1.0% of bacteria may have come from another source, showing the safety of the process used to treat milk samples. CONCLUSION: The pasteurization process increased the bacterial diversity. We selected taxa capable of surviving the process, which could proliferate after the treatment without being a risk for infants.

Glioblastoma cells express crucial enzymes involved in androgen synthesis: 3ß-hydroxysteroid dehydrogenase, 17-20α-hydroxylase, 17ß-hydroxysteroid dehydrogenase and 5α-reductase.

Glioblastoma (GB) is the most common and aggressive primary brain tumour in adult humans. Therapeutic resistance and tumour recurrence after surgical removal contribute to poor prognosis for glioblastoma patients. Men are known to be more likely than women to develop an aggressive form of GB, and differences in sex steroids have emerged as a leading explanation for this finding. Studies indicate that the metabolism and proliferation of GB-derived cells are increased by sex steroids, the expression of androgen receptors (ARs) and the synthesis of androgens and oestrogens, suggesting that these hormones have a role in the tumour pathogenesis. The expression of aromatase, the enzyme that converts androgens to oestrogens, has been reported in glial cells and GB cell lines. Thus, it was necessary to test whether the steroidogenic enzymes involved in androgen synthesis are expressed in GB cells. Therefore, here, we investigated the expression of four key enzymes involved in androgen synthesis in human-derived GB cells. U87 cells were cultured in Dulbecco's modified Eagle medium plus foetal bovine serum and antibiotics on slides for immunocytochemistry or immunofluorescence. U87, LN229 and C6 cells were also cultured in multi-well chambers to obtain proteins for Western blotting. We used primary antibodies against 3ß-hydroxysteroid dehydrogenase (3ß-HSD), 17α-hydroxilase/17,20-lyase (P450c17), 17ß-hydroxysteroid dehydrogenase (17ß-HSD) and 5α-reductase. Immunocytochemistry, and immunofluorescence results revealed that glioblastoma cells express 3ß-HSD, P450c17, 17ß-HSD and 5α-reductase proteins in their cytoplasm. Moreover, Western blot analyses revealed bands corresponding to the molecular weight of these four enzymes in the three GB cell lines. Thus, glioblastoma cells have the key enzymatic machinery necessary to synthesize androgens, and these enzymes might be useful targets for new therapeutic approaches.