In utero exposure to persistent environmental pollutants
Thesis event information
Date and time of the thesis defence
Place of the thesis defence
Markku Larmas Auditorium (H1091), Dentopolis
Topic of the dissertation
In utero exposure to persistent environmental pollutants
Doctoral candidate
Licentiate of Medicine Ella Vuoti
Faculty and unit
University of Oulu Graduate School, Faculty of Medicine, Research Unit of Translational Medicine
Subject of study
Anatomy and cell biology
Opponent
Professor Leea Keski-Nisula, University of Eastern Finland
Custos
Professor Petri Lehenkari, University of Oulu
Persistent environmental pollutants accumulate in tissues already during fetal development
Heavy metals and persistent organic pollutants (POPs) can be detected in the solid tissues of the fetus under background exposure. The doctoral dissertation highlights the need for more precise assessment of fetal exposure, as it is typically evaluated from maternal or umbilical cord blood, and little is known about accumulation in solid tissues.
Heavy metals and POPs persist in the environment for long periods and may accumulate in animals and biomagnify in food chains. Although their use is now legally restricted, they continue to occur in nature due to their chemical stability. In animal tissues, heavy metals tend to accumulate in bone, while POP compounds accumulate in adipose tissue. During pregnancy, chemicals stored in maternal tissues may be released into the bloodstream when calcium and adipose reserves are mobilized to support fetal growth.
In this doctoral thesis, the distribution of heavy metals and POP compounds between maternal and fetal tissues was examined in two studies using sheep as an animal model. In addition, the function of bone resorbing osteoclasts derived from different cell sources was compared.
The first sub-study compared the differentiation of stem cells isolated from adult blood, adult bone marrow, and umbilical cord blood (representing fetal cells) into bone resorbing osteoclasts in cell culture. The study found that osteoclasts derived from different sources differed: bone marrow derived osteoclasts resorbed bone most efficiently, and osteoclasts derived from adult blood were more numerous and contained more nuclei than those derived from umbilical cord blood. This supports the understanding that the physiology of the fetus and newborn is not simply a smaller version of the adult.
In the second sub study, concentrations of metals were measured in the blood, liver, placenta, and bone of sheep and their fetuses. Metal concentrations in blood and liver were largely similar between ewes and fetuses, whereas concentrations in bone were higher in the ewes.
The third sub study examined POP concentrations in adipose tissue from ewes and their lambs. POP compounds were detected in all fat samples, and fetal concentrations ranged from 30% to 103% of maternal concentrations depending on the compound.
The dissertation did not investigate the health effects of environmental pollutants, and results obtained from the sheep model cannot be directly applied to humans. The findings provide rare information on how even low level background exposure can be reflected in fetal tissues. The results may be useful in developing methods for assessing fetal exposure and in future research on the potential long term effects of chemical exposure during early development.
Heavy metals and POPs persist in the environment for long periods and may accumulate in animals and biomagnify in food chains. Although their use is now legally restricted, they continue to occur in nature due to their chemical stability. In animal tissues, heavy metals tend to accumulate in bone, while POP compounds accumulate in adipose tissue. During pregnancy, chemicals stored in maternal tissues may be released into the bloodstream when calcium and adipose reserves are mobilized to support fetal growth.
In this doctoral thesis, the distribution of heavy metals and POP compounds between maternal and fetal tissues was examined in two studies using sheep as an animal model. In addition, the function of bone resorbing osteoclasts derived from different cell sources was compared.
The first sub-study compared the differentiation of stem cells isolated from adult blood, adult bone marrow, and umbilical cord blood (representing fetal cells) into bone resorbing osteoclasts in cell culture. The study found that osteoclasts derived from different sources differed: bone marrow derived osteoclasts resorbed bone most efficiently, and osteoclasts derived from adult blood were more numerous and contained more nuclei than those derived from umbilical cord blood. This supports the understanding that the physiology of the fetus and newborn is not simply a smaller version of the adult.
In the second sub study, concentrations of metals were measured in the blood, liver, placenta, and bone of sheep and their fetuses. Metal concentrations in blood and liver were largely similar between ewes and fetuses, whereas concentrations in bone were higher in the ewes.
The third sub study examined POP concentrations in adipose tissue from ewes and their lambs. POP compounds were detected in all fat samples, and fetal concentrations ranged from 30% to 103% of maternal concentrations depending on the compound.
The dissertation did not investigate the health effects of environmental pollutants, and results obtained from the sheep model cannot be directly applied to humans. The findings provide rare information on how even low level background exposure can be reflected in fetal tissues. The results may be useful in developing methods for assessing fetal exposure and in future research on the potential long term effects of chemical exposure during early development.
Created 30.7.2026 | Updated 31.7.2026