Blood-based sEV Proteins for Early Detection of 2 Diabetes

Obesity is strongly associated with insulin resistance, prediabetes, and type 2 diabetes. Current screening approaches for prediabetes and type 2 diabetes mainly rely on glucose-related measurements, including fasting plasma glucose, OGTT, and HbA1c. These measurements are useful for identifying abnormal glucose regulation, but additional blood-based biomarkers may help identify obese individuals who are at higher risk of type 2 diabetes before or during the early stage of glucose dysregulation.

Small extracellular vesicles are circulating membrane-bound vesicles that carry proteins and other biomolecules. Previous work from the study team showed that integrin-β2 and extracellular matrix protein 1 were increased in circulating small extracellular vesicles from obese or overweight individuals. Given the well-known association between integrin/ECM and the development of insulin resistance, the study hypothesize is that integrin-β2 and ECM1 proteins in the circulating sEVs can be used for the early detection of obese individuals at risk for T2D.

This is an observational biomarker study in human participants. After informed consent, participants will undergo body mass index assessment and fasting blood collection after an overnight fast. Fasting plasma glucose and HbA1c will be measured by a registered clinical laboratory. BMI and glucose-related testing results, participants will be assigned to comparison groups including non-overweight/non-obese individuals, overweight/obese individuals, non-overweight/non-obese individuals with prediabetes or type 2 diabetes and overweight/obese individuals with prediabetes or type 2 diabetes.

Blood samples will be used for isolation of circulating small extracellular vesicles according to established laboratory protocols. The levels of integrin-β2, extracellular matrix protein 1, and other candidate small extracellular vesicle proteins will be measured. Protein levels will be compared across the study groups to determine whether these circulating small extracellular vesicle protein signatures are specifically associated with obesity-related prediabetes or type 2 diabetes.

The planned sample size for the human observational component is 120 participants, with 30 participants in each of the four groups. The sample size was calculated using G*Power to compare protein expression levels across four groups, assuming a medium effect size of 0.25, an alpha level of 0.05, and 80% statistical power. Participants will be assigned study codes. The code identifier file and study data will be stored separately in password-protected computers and will be accessible only to research personnel. Data will be deleted five years after study completion.

The main purpose of this study is to examine whether elevated integrin-β2 and /or ECM1 (and the protein candidates in contingency plan) in circulating sEVs is specific for obesity-associated T2D.This proposed study is critical to provide supporting data for the implementation of a subsequent prospective cohort study to validate whether integrin β2/ECM1 proteins in circulating sEVs can be used for the early detection of obese individuals at risk for T2D.

Inclusion criteria

• Hong Kong citizens;
• Male or female;
• Aged 40-59 years;
• Able and willing to provide written informed consent;
• Willing to undergo BMI assessment and fasting blood collection after an overnight fast of at least 8 hours.

Exclusion criteria

• Cardiovascular disease.
• Cancer.
• History of surgery, as specified in the study protocol.
• Infectious disease.
• Osteoarthritis.
• Genetic disease.
• Pregnancy or breastfeeding.
• Suspected pregnancy.