Imaging beta-cell death with a near-infrared probe

Area of Science:

• Endocrinology
• Molecular Biology
• Medical Imaging

Background:

• Beta-cell apoptosis plays a critical role in the pathogenesis of both type 1 and type 2 diabetes.
• Current methods for detecting beta-cell apoptosis are limited to in situ strategies, hindering real-time in vivo assessment.

Purpose of the Study:

• To develop and validate a novel in vitro and ex vivo method for measuring beta-cell apoptosis in diabetic models using a Cy5.5-labeled annexin V probe.
• To assess the potential of this probe for early, in vivo detection of diabetes-associated beta-cell death.

Main Methods:

• Utilized streptozotocin-treated BALB/c and NOD mice (type 1 diabetes models) and db/db mice (type 2 diabetes model).
• Administered Cy5.5-labeled annexin V intravenously and assessed its accumulation and localization in pancreatic tissues.
• Corroborated probe selectivity using transferase-mediated dUTP nick-end labeling (TUNEL) staining.

Main Results:

• Cy5.5-labeled annexin V demonstrated differential accumulation in the pancreata of diabetic mice compared to nondiabetic controls.
• The probe specifically localized to apoptotic events within diabetic islets, confirming its selectivity.
• Established measurable differences in apoptosis levels between diabetic and control animal groups.

Conclusions:

• Cy5.5-labeled annexin V serves as an effective tool for quantifying beta-cell apoptosis in diabetic models.
• The developed probe enables real-time, in vivo identification of early-stage beta-cell death in diabetes.
• This approach offers a promising strategy for tracing disease progression and understanding diabetes pathology.