Effects of Probiotics on Inflammatory Responses in Neuronal Tissue

by Laura O’Dea, Meredith LeBel, Nicole Haynes

Faculty mentor: Dr. Deborah O’Dell

Alzheimer’s disease (AD) is a neurodegenerative disease that affects more than 40 million people. While the pathophysiology has yet to be fully elucidated, some studies suggest AD associated chronic inflammation is caused by hyperactive microglia that produce pro-inflammatory factors. Probiotics have been shown to have anti-inflammatory properties and may influence neurochemistry via the gut-brain-axis, which controls communication between the intestines and brain, crossing over the blood brain barrier (BBB). A model of the BBB was constructed with a double transwell system to clarify the effects of probiotics on cerebral inflammation. Microglia cells grown in the basolateral chamber were co-cultured with endothelial cells in the upper compartment while an astrocyte monolayer separated the two compartments. Once the system was exposed to human peripheral blood T-cells and combined with histamine (probiotic anti-inflammatory product), formic acid (probiotic inflammatory product), both, or neither, the microglial medium was collected and analyzed for tumor necrosis factor α (TNFα) and interleukin-10 using ELISA. ANOVA and T-Tests were run and showed no significant results, except for the histamine and formic acid combination. In the combination treatment, levels of TNFα were slightly different than the control (p = 0.00006), contrary to what was expected. Under these conditions, probiotics do not reduce inflammation in the brain and thus cannot effectively treat AD patients. However, in the future, more experiments should be conducted with multiple inflammatory and anti-inflammatory molecules as there could be overlapping interactions between several probiotic products that produce advantageous metabolic effects and mitigate elevations in inflammatory responses.

5 Replies to “Effects of Probiotics on Inflammatory Responses in Neuronal Tissue”

  1. Thank you for sharing your work. I am curious to learn more about the transwell system and how close it mimics the BBB.

    1. We decided to model the BBB using a transwell system because we wanted a way to represent the barrier without directly using live neural tissue. Essentially our model of the BBB involves a double transwell system where we cultured an outer layer of endothelial cells with astrocytes just on the inside of the barrier. This first layer of the transwell was meant to mimic a very basic model of the blood brain barrier, with the most significant of the cells included being the astrocytes. Additionally, the microglia were cultured on the inside well of the system to reflect the inside of the BBB. Based on prior research, this transwell system was a solid potential model of the BBB, and was the most cost effective option when compared to a four co-cultured cell model which would have included pericytes and neurons. In the future, research using this four cell model may deliver improved results.

  2. Wonderful job Laura and Meredith (or is it Meredith and Laura?!?)… and Nicole as well. Very impressed – so as a followup to Dr. Slunt’s questions… are there intrinsic growth factors in the astrocytes used in the trans-well system that cause them to grow in to make an ‘impermeable’ barrier?

    1. The tightly regulated permeability of the BBB is constructed by an astrocytic endfeet interface with endothelial cells that form tight junctions. Astrocytes release growth factors like VEGF, GDNF, bFGF, and ANG-1, which help form tight junctions and increases in enzyme systems and transporter expression.

  3. Looks like a terrific project. Great work. Thanks for sharing this with us. Best wishes,

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