Researchers Reveal Connection Between Insulin and Human Lactation
A new study conducted by a research team from the Cincinnati Children’s Hospital, from the United States, reveals a connection between insulin and lactation. This study adds more information to their precedent studies regarding mothers who experience insufficient lactation. It is also the first study that describes the increased sensitivity of the mammary gland towards insulin during lactation. Furthermore, it is the first study the accurately depicts the activation of specific genes during lactation.
The research team used RNA sequencing in order to create an extremely detailed blueprint of the lactation process in the human mammary glands. The study, authored by Laurie Nommsen-Rivers was recently published in the online journal PLOS ONE. Professor Nommsen-Rivers has conducted previous studies regarding the lactation process of female patients suffering from a sub-optimal glucose metabolism. This type of metabolism occurs in patients that are overweight, obese or in patients with an advanced maternal age. A sub-optimal glucose metabolism causes the lactation process to slow down, thus, milk takes longer to form. Her study was one of the first to suggest a link between insulin and lactation. Her current paper reveals how the human mammary gland increases its sensitivity towards insulin during the lactation process.
Scientists thought for many years that insulin doesn’t have a role in the regulation of cells that produce milk, due to the fact that insulin isn’t needed by the cells for glucose intake. However, Nommsen-Rivers’ study reveals that insulin plays a more important role, other that just facilitating glucose intake. According to the authors of the study, during the transition of the breast towards a bio-factory for proteins, carbohydrates and fats necessary for newborn feeding, there is a major increase in activated insulin receptors, which eventually causes a dysregulation of insulin. Due to the fact that approximately 20% of women between the ages of 20 and 44 are diagnosed with pre-diabetes, authors say that there is a probability of up to 20% that future mothers will have an insufficient milk supply for their newborns.
Through the use of a non-invasive maneuver called RNA sequencing, researchers were able to observe the RNA sequences found in the cells of the mammary gland. These RNA sequences are responsible for the production of the specific proteins found in the human milk. Furthermore, the research team created the first database of genes expressed in the mammary gland available to the general public. The RNA sequencing method allows for the creation of highly detailed portraits of the genes that are expressed in the milk-producing cells found in the human mammary glands. Researchers discovered the synchronous activation and deactivation or several genes throughout the lactation process, starting with the colostrum and ending with the mature milk.
More specifically, the PTPRF gene, known to play an important role in the suppression of intracellular signals that would normally be triggered by the binding of insulin to its cellular receptor, might be used as a biomarker that would link insulin resistance to an insufficient milk secretion. The research team is currently planning a phase I/II clinical trial regarding the action of a drug that is already used to control the glucose levels of type 2 diabetes patients. The clinical trial will be conducted in order to discover whether or not the drug is able to improve the action of insulin on the cells from the mammary gland, thus increasing the quantity of produced milk. Even though the use of a drug is not the best way to treat the sub-optimal glucose metabolism, Dr. Nommsen-Rivers agrees that it would be an excellent start to prove or disprove her recent discovery through the use of a placebo-controlled double-blind clinical trial.