A method for mass harvesting islets (Brockmann bodies) from teleost fish

Area of Science:

• Endocrinology
• Xenotransplantation
• Islet Cell Biology

Background:

• Brockmann bodies (BBs) in fish are sources of insulin-producing islet cells.
• Current microdissection methods for harvesting BBs are time-consuming and inefficient for large-scale research.
• Tilapia BBs are a valuable, inexpensive resource for xenotransplantation studies.

Purpose of the Study:

• To develop an easier and more efficient method for harvesting tilapia Brockmann bodies.
• To increase the yield of BB tissue for xenotransplantation research.
• To assess the functionality of mass-harvested BBs in transplantation models.

Main Methods:

• A novel enzymatic digestion method using collagenase Type II was adapted from adipocyte isolation.
• BB regions were digested in Hank's balanced salt solution (HBSS) at 37°C.
• Isolated BBs were handpicked using a siliconized pipette after adipocyte separation.

Main Results:

• The enzymatic method approximately doubles or triples the yield of BB tissue per donor fish.
• Transplantation of mass-harvested BBs into diabetic mice achieved long-term normoglycemia.
• The required donor fish weight per recipient was reduced by 50%.

Conclusions:

• The new enzymatic method provides a more efficient and higher-yield approach for harvesting tilapia BBs.
• Mass-harvested BBs retain functionality and are suitable for xenotransplantation.
• This method significantly improves the feasibility of using tilapia BBs in large-scale transplantation studies.