Project Lead(s): Zully Puyén
Almost half of the regions in Peru have increased mining activity and, in these areas, the majority of the population is coping with high levels of lead in their blood (over 10 ug/dL).
Chronic exposure to heavy metals (even at low levels) is detrimental to human health and the issue has become a public health concern in Peruvian regions where mining is prevalent.
To date, no studies are available on successful measures for removing heavy metals from the human body.
The objective of this project was to develop a probiotic beverage to be used as a dietary supplement capable of removing heavy metals from the body.
The first step in the project involved identifying whether bacteria of the gastrointestinal microbiome from people who are living in areas with high exposure to heavy metal pollution have acquired the ability to resist and depurate heavy metals.
A total of 2,905 isolates from stool cultures was obtained. The probiotic potential of the bacterial isolates recovered from stool samples of people was determined by DNA extraction and purification, molecular characterization by PCR assays and DNA sequencing, using 16S rDNA and HEP-2 cell adhesion assays. These were performed for bacterial isolates resistant to heavy metal.
Assessment of the genetic basis of depurating activity of heavy metals from probiotic bacteria identified during the project was also done.
Mice were then treated with the probiotic and peripheral blood was extracted to evaluate the level of arsenic, mercury and lead collected in two phases (corresponding to previous probiotic treatment) and, after 20 days of treatment with probiotic bacteria, to evaluate the depurating capacity of Lactobacillus sp. strains identified during the project.
Although the team was able to demonstrate the depurating capacity of the bacteria isolated in laboratory conditions, they were not able to demonstrate the potential of using a dietary probiotic to detoxify heavy metals in the body using animal models.
About 300 bacterial strains resistant to high concentrations of heavy metals were selected, based on the minimum inhibitory concentration test for heavy metals, for further laboratory procedures.
Molecular identification and probiotic potential of bacterial strains indicated that about 10% of selected strains belonged to the genus Lactobacillus, of which a total of six bacterial strains showed adherence pattern in HEP-2 cells.
These strains were used in subsequent methods, including genomic characterization and in vivo assays using murine models.
Although preliminary in vivo results showed a reduction in arsenic levels in the peripheral blood of mice after 20 days of treatment, no significant differences were observed when compared with the control group.
Further in vivo assays are necessary using the comprehensive collection of candidate strains of Lactobacillus to fully demonstrate the potential benefit of these particular probiotic bacteria.