RESUMO
Melatonin is a hormone secreted mainly by the pineal gland and acts through the Mel1A and Mel1B receptors. Among other actions, melatonin significantly increases osteogenesis during bone regeneration. Human adipose-derived mesenchymal stem cells (ADSCs) are also known to have the potential to differentiate into osteoblast-like cells; however, inefficient culturing due to the loss of properties over time or low cell survival rates on scaffolds is a limitation. Improving the process of ADSC expansion in vitro is crucial for its further successful use in bone regeneration. This study aimed to assess the effect of melatonin on ADSC characteristics, including osteogenicity. We assessed ADSC viability at different melatonin concentrations as well as the effect on its receptor inhibitors (luzindole or 4-P-PDOT). Moreover, we analyzed the ADSC phenotype, apoptosis, cell cycle, and expression of MTNR1A and MTNR1B receptors, and its potential for osteogenic differentiation. We found that ADSCs treated with melatonin at a concentration of 100 µM had a higher viability compared to those treated at higher melatonin concentrations. Melatonin did not change the phenotype of ADSCs or induce apoptosis and it promoted the activity of some osteogenesis-related genes. We concluded that melatonin is safe, non-toxic to normal ADSCs in vitro, and can be used in regenerative medicine at low doses (100 µM) to improve cell viability without negatively affecting the osteogenic potential of these cells.
RESUMO
BACKGROUND The microbiome is the collection of all micro-organisms and their genes, which naturally live in and on the body. The cervical and endometrial bacterial microbiome has previously been reported to affect fertility and influence the outcomes of assisted reproductive therapy (ART), including embryo transfer. This study aimed to evaluate the cervical and endometrial bacterial microbiome in 177 women treated for infertility before, during, and after embryo implantation, and the outcomes. MATERIAL AND METHODS Cervical and endometrial swabs were collected from 177 women diagnosed with infertility at 3 time points: (1) during the initial examination, (2) during implantation, (3) 10-14 days after implantation. Next-generation sequencing (NGS) was used to analyze the bacterial microbiome. Taxonomic identification was performed with the Usearch algorithm. RESULTS There was a significant change in the number of patients with Escherichia coli depending on the collection time. For the first swab collection, there were significant negative relationships between the percentage of Gardnerella vaginalis and Lactobacillus spp. For the second collection, there was a negative relationship between Lactobacillus helveticus and Lactobacillus jensenii. For the third collection, negative relationships were found between Escherichia coli and Lactobacillus spp. A similar distribution of the bacterial microbiome was observed in all 3 swab collections. CONCLUSIONS Lactobacillus spp. were the main bacteria identified in the cervix and endometrium, present before, during, and after successful embryo transfer. E. coli and G. vaginalis reduced the protective effect of Lactobacilli before, during, and after embryo transfer.