The Repository @ St. Cloud State

Open Access Knowledge and Scholarship


Brigita Fiske

Date of Award


Culminating Project Type


Degree Name

Biological Sciences - Cell and Molecular: M.S.




College of Science and Engineering

First Advisor

Marina Cetkovic-Cvrlje

Second Advisor

Nathan Bruender

Third Advisor

Timothy Schuh

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Keywords and Subject Headings

Type 1 Diabetes, Yerba Mate, Ilex paraguariensis, T cell, immunomodulatory, in vivo, anti-inflammatory


Type 1 Diabetes (T1D) is a T cell-mediated autoimmune disease that attacks the pancreas' insulin-producing b-cells. As immunotherapies have failed to reverse T1D, the focus has turned to prevention, particularly during the subclinical, pre-stage 1 when auto-reactive T cells are not yet active. Yerba mate (YM) or Ilex paraguariensis has been shown to have anti-inflammatory and hypoglycemic properties that make it a potentially safe and inexpensive therapeutic agent to delay the onset of the disease. This study aimed to evaluate YM's effect on the progression of T1D and T cell populations in two mouse models of T1D: streptozotocin (STZ)-induced C57BL/6 (STZ-B6) strain and non-obese-diabetic/ShiLtj (NOD) strain.

YM was given daily as an infusion ad libitum at 4% and 2% w/v. In the STZ-B6 model, YM treatment began before diabetes induction by low-dose STZ and continued daily for a total period of 6 weeks. In the NOD model, YM treatment began at 5 weeks of age and continued daily for 19 weeks. Glycemia and body weights were monitored bi-weekly and weekly for the STZ-B6 mice and NOD mice, respectively. At the endpoint, animals were euthanized to analyze immunological parameters of cell viability, T cell proliferation, T cell immunophenotypes, and related cytokine production in their spleens. An in vitro T cell assay was also conducted on splenocytes from healthy NOD mice directly treated with 0.5-1000 mg/mL YM.

YM treatment significantly decreased glycemia and T1D incidence for both concentrations in the STZ-B6 model over 6 weeks while increasing or maintaining body weight with 4% and 2% w/v, respectively. YM at 4%, but not 2%, w/v significantly decreased glycemia in NOD mice over 19 weeks of treatment without affecting T1D onset. However, both concentrations induced body weight loss in NOD mice starting around 14 weeks of treatment.

Further ex vivo data showed YM treatment in STZ-B6 mice at both concentrations significantly lowered T cell proliferation, caused transient changes in T cell immunophenotypes, and suppressed both pro-inflammatory and anti-inflammatory cytokine production. In NOD mice, 4% YM (w/v) treatment showed a transient effect at the 12 weeks of age timepoint in lowering T cell, Th, and Tc populations and reducing production of pro-inflammatory cytokines IL-6 and IFN-, However, this anti-inflammatory effect was not evident at 17 weeks of age or the endpoint.

YM exposure of T cells in vitro caused a dose-dependent decrease of T cell proliferation. The concentrations of all studied cytokines, IL-2, TNF-a, IFN-, IL-17, IL-4, and IL-10, were suppressed with addition of 1000 g/mL YM, suggesting its toxicity. A dose-dependent reduction and increase of IFN- and IL-2 production, respectively, was observed whereas other studied cytokines were not affected by lower concentrations of YM.

In summary, this is the first study to show YM's potential to delay the onset of T1D. Our results corroborate with other studies that tout YM's anti-proliferative and hypoglycemic action, in addition to its immunomodulatory action on T cells.


To my mentors and colleagues who encouraged me through this project, thank you. Dr. Steiner, thank you for leaving me with a lasting impression that drove me to teach to your level and to pursue science again. Dr. C, thank you for taking a chance on a private school teacher. You have devoted incredible time and energy to help me succeed, and now a world of opportunity is open to me. Jenna, thank you for your patience when training me and thank you for your friendship. To my undergraduate researchers, Brian Lorenz, Ann Sieben, and Barb Kjellberg, thank you for your kindness and consistent help. I would not have finished without you. To my committee, thank you for your helpful criticism and questions that challenged me to deepen my understanding. To all my family and friends, thank you for your encouragement. To Sam, my loving husband, thank you for supporting me in anything I do. Above all, I thank God for providing me with the means to explore the fascinating world he has made.—Soli deo gloria



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.