Exercise immediately prior to and during pregnancy restores important tissues in the body, making them better able to control blood sugar levels and reducing the risk of long-term health problems, new research in mice suggests.
Researchers from the University of Cambridge, who led the study published today in the journal Physiological reports, say the findings underline the importance of an active lifestyle in planning a pregnancy.
In the UK, more than half of all women are of reproductive age and nearly one third of pregnant women are overweight or obese. This is particularly worrying because being overweight or obese during pregnancy increases the risk of complications in the mother, such as gestational diabetes, and makes both her and her baby susceptible to developing metabolic diseases such as type 2 diabetes in the years after pregnancy.
Exercise is known to improve the way the body manages blood sugar levels and thereby reduces the risk of type 2 diabetes and metabolic syndrome in non-pregnant women. It also has positive effects before and during pregnancy, with favorable results for both mother and child, the prevention of excessive pregnancy weight gain and the development of gestational diabetes, and the need for insulin use in women who have already developed gestational diabetes. However, little is known about the changes that exercise causes in the tissues of an obese pregnant mother.
To answer these questions, researchers from the University of Cambridge fed mice a sugary, high-fat diet so that they became obese and then the obese mice were trained. The mice trained for 20 minutes a day on a treadmill for at least a week before their pregnancy and then 12.5 minutes a day until day 17 of the pregnancy (pregnancy takes about 20 days in mice).
Mice are a useful model for studying human diseases because their biology and physiology have a number of important characteristics in common with those of humans, including the display of metabolic changes with obesity / obesity diets and in the female body during pregnancy.
The researchers discovered that the beneficial effects on metabolic health in obese mothers were related to changes in the way molecules and cells communicate in maternal tissues during pregnancy.
"A moderate level of exercise immediately before and after pregnancy leads to important changes in different tissues of the obese mother, making the tissues more similar to those seen in non-obese mothers," Dr. Amanda Sferruzzi-Perri, a Royal Society Dorothy Hodgkin Research Fellow of the Center for Trophoblast Research of the Department of Physiology, Development and Neuroscience of the University of Cambridge, who co-led the study.
"We believe that these changes can explain how exercise improves the metabolism of the obese mother during pregnancy and in turn can prevent her baby's developing early signs of type 2 diabetes after birth."
The most important organs of the mother that were influenced by movement were:
. white fatty tissue – the fatty tissue that stores lipids and can be found in various parts of the body, including under the skin and around internal organs;
. skeletal muscle – muscle tissue that uses glucose and fats for contraction and movement;
. the liver – the organ that stores and synthesizes lipids and glucose.
Exercise influences important signaling pathways – the ways in which molecules and cells in the tissue communicate – involved in responding to insulin (the hormone that stimulates glucose uptake by white fatty tissue and skeletal muscle), in the storage and breakdown of lipids (blood and tissue fats) ) and in protein growth and synthesis.
White adipose tissue showed the greatest number of changes in response to physical exercise in the obese pregnant mouse and was restored to a state similar to that in the tissue of non-obese mothers. This suggests that insulin resistance of the mother's white fat tissue may be the cause of poor glucose-insulin treatment in obese pregnancies. The findings are different from those in non-pregnant animals, where physical exercise usually influences insulin signaling in skeletal muscle.
In addition, earlier work by the team showed that physical activity improves the sensitivity to insulin and glucose management throughout the body in the obese mother. It also prevents the development of insulin resistance in the offspring of obese mothers after birth. Low insulin sensitivity / insulin resistance requires larger amounts of insulin to control blood sugar levels.
"Our findings underline the importance of an active lifestyle and eating a healthy, balanced diet when planning pregnancy, for both the mother and her developing child," said co-chief professor Susan Ozanne of the Wellcome Trust-Medical Research Council Institute of Metabolic Science at the University of Cambridge.
"This is important to help reduce the risk of adverse maternal health problems and subsequent health problems for her child."
This work received funding from the European Union, Medical Research Council, Biotechnology and Biological Sciences Research Council, British Heart Foundation, São Paulo Research Foundation, Center for Trophoblast Research and the Royal Society.
Musial, B et al. Exercise changes the molecular pathways of insulin signaling and lipid treatment in maternal tissues of pregnant mice with obesity. Physiological reports; August 28, 2019; DOI: 10,14814 / phy2.14202
All experiments were performed in accordance with the UK Home Office Animals (Scientific Procedures) Act 1986.
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