Joslin Diabetes Center is one of twenty-two Type 1 Diabetes TrialNet International Clinical Centers at the forefront of type 1 diabetes research. Led by Jason Gaglia, MD, MMSc, the TrialNet team at Joslin Diabetes Center is dedicated to preventing type 1 diabetes and stopping disease progression by preserving insulin production before and after diagnosis.

Our Team

Jason Gaglia, MD, MMSc

Jason Gaglia, MD, MMSc

Principal Investigator

Dr. Gaglia’s research has been focused on immunology and type 1 diabetes. His accomplishments include cloning the immune regulatory molecule TIM-3, being a member of the National Institutes of Health Clinical Islet Transplant Program, and leading a clinical trial demonstrating the feasibility of using magnetic resonance imaging to measure inflammation in the pancreas with the development of type 1 diabetes.

Maria Koen

Maria Koen, NP-C, CDE

Research NP/Sub-Investigator

Maria Koen is a Family Nurse Practitioner and Certified Diabetes Educator who has specialized in the care of patients with diabetes since 2001. Her clinical and research interest areas include management of Type 1 diabetes, advanced technologies including pump therapy and CGM systems and modalities aimed at prevention of diabetes.  In her role as a clinical research nurse practitioner, she conducts research focused on improvement in glycemic control and/or preservation of beta cell function in individuals with Type 1 diabetes. 

Christina Astley

Christina Astley, MD, ScD


Christina is a physician-scientist at Boston Children's Hospital with research interests in the drivers of type 1 diabetes remission and dysglycemia (supported by a K23 from the National Institute of Diabetes and Digestive and Kidney Diseases), as well as causal inference methods for understanding the origins of complex diseases. Her background is in pediatric endocrinology (MD from the Harvard-MIT Division of Health Sciences and Technology at Harvard Medical School, Residency and Fellowship at Boston Children's Hospital) as well as mathematical modeling and epidemiology (ScD from the Harvard School of Public Health). She is currently an Instructor in Pediatrics at Harvard Medical School, an Attending in Endocrinology at Boston Children's Hospital, and Affiliate Faculty of the Joslin Diabetes Center. 

brittany resnick

Brittany Resnick, FNP-BC, MSN

Sub-Investigator/Clinical Trials Manager/Research NP

Brittany is the Clinical Trials Manager for the Gaglia research group at the Joslin Diabetes Center. She is a Family Nurse Practitioner and received both her Bachelor’s in Nursing and Master’s in Nursing from Simmons University. Brittany joined the TrialNet team in 2013 and has been the Clinical Trials Manager for the Gaglia research team since 2022. She previously worked as a research nurse in the United Kingdom, aiding in improving the identification and management of patients with monogenic diabetes at the University of Exeter. In her role as Clinical Trials Manager, she manages a portfolio of preventive and new-onset type 1 diabetes clinical research trials.


Hailey Roseman, BS

Research Assistant

Hailey is one of the Research Assistants for Dr. Gaglia’s immunobiology research team at the Joslin Diabetes Center. She received degrees in Biology and Neuroscience from UMass Amherst upon graduating in 2023. During her undergraduate experience, she conducted research on the links between the gut microbiome and inflammatory-associated diseases. Hailey is excited to apply her knowledge to TrialNet studies and learn more about immunobiology.


Michelle Zhang, BA

Research Coordinator

Michelle is the Research Coordinator on Dr. Gaglia’s immunobiology research team at the Joslin Diabetes Center. She received her Bachelor of Arts degree in Biological Sciences from Smith College in 2023. Michelle joined the TrialNet team in July 2023, and she is excited to work on clinical trials studying the prevention and intervention of type 1 diabetes in children and adults.


Laurie Higgens, MS, RN, LDN, CDCES

Diabetes Educator

Laurie is the Coordinator of Pediatric Nutrition Education & Research working in the Pediatric, Adolescent and Young Adult Section at Joslin Diabetes Center in Boston, MA. Ms. Higgins is on the planning committee for educational opportunities offered at Joslin Diabetes Center and her clinical and research interest include management of Type 1 diabetes, advanced technologies including pump therapy and CGM systems.

Research Studies

Risk Screening Risk Screening for Relatives

If you have a relative with T1D, you may be eligible for risk screening that can detect the early stages of T1D years before symptoms appear. More

Monitoring Monitoring

Depending on your risk screening results, you may be eligible for monitoring. We’ll monitor you for disease progression and let you know if you become eligible for a study. More

Long Term Long-Term Follow-up

If you are diagnosed with T1D while participating in one of our prevention studies, we’re still here for you. You can continue to receive personal monitoring while helping us learn more. More

Newly Diagnosed Tolerance Using Plasmid (TOPPLE) Study: Phase 1

TrialNet is testing the safety of a new treatment, NNC0361-0041, in adults diagnosed with type 1 diabetes (T1D) in the past 48 months. This is a Phase 1 study, which means it is the first time this treatment is being tested for safety in people. If this study results in no safety concerns, we plan to conduct a larger study to see if this same treatment can slow down or stop T1D in people at high risk, before clinical diagnosis. More