Fetal membrane defenses against GBS infection

7/22/2019

Ryan Doster, MD, PhD

Ryan Doster, MD, PhD
Dr. Ryan Doster is an Instructor of Clinical Medicine in the Division of Infectious Diseases at Vanderbilt University Medical Center. Dr. Doster’s research focuses on understanding how GBS causes infection during pregnancy by examining how GBS interacts with immune cells within the reproductive tract.

Marti Perhach

7/22/2019 09:41:38 pm

Thank you, Dr. Doster, for your very clear explanations about the fetal membranes. As a GBS stillbirth mom, I especially appreciate your work in this area.

Susanna Wright

7/23/2019 10:14:16 am

Great presentation! You mentioned the use of the strain GB37. Have you found any difference in outcomes with other strains?

Ryan Doster

7/28/2019 03:04:31 pm

Susanna, that is a great question. We do see differences between GBS strains in terms of their ability to invade fetal membrane tissues, cause infections in our mouse models, and to colonize the reproductive tract. We also see that different GBS strains induce slightly different levels of immune responses (cytokine production) on our infection models. We do not fully understand why this happens. Each strain is unique. Our lab and others have looked for commonalities to try to better predict why some women colonized with GBS develop severe infections whereas others do not. To date we have not found a specific factor or bacterial trait that seems to occur more commonly during infection than asymptomatic colonization.

Marcia Remsen

7/23/2019 10:32:45 am

Very interesting how you explained the consequences of inflammation and how the body's own response consequently can deteriorate the connective tissue of the fetal membranes. In the samples you've studied, have you found variance in if the amount of immune cells present impacts the speed of deterioration?

Ryan Doster

7/28/2019 03:12:29 pm

Thank you for the question Marcia. I don't think we fully know the answer to that, particularly regarding the speed of deterioration. I think it is understood that the number of immune cells present represent a higher degree of inflammation (see the stages of chorioamnionitis slide). This certainly increases the risk for rupture, but since we can not see this happen in real time (only getting samples for analysis after the event happens) I do not think we know for sure. I would suspect that the more immune cells present, the more likely (and the faster) rupture may occur.

Marti Perhach

7/23/2019 03:32:01 pm

What steps should a pregnant woman take if she would like to have her placenta donated for research?

Ryan Doster

7/28/2019 03:20:05 pm

Great question Marti. Certainly our understanding of pregnancy infections is greatly aided by women donating placenta tissue for research. The most important thing that you can do if approached by a research coordinator is to say 'yes.' This work is mostly being done at major university centers/hospitals because the tissues must be used quickly after delivery before it starts to break down. Because of this, most deliveries at community hospitals are not able to be used for research.

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