Finnish researchers find way to grow blood vessels in mini organs

A research team at the University of Oulu has developed a technique to cultivate functional blood vessels within organoids, which are miniature organ models, said the university in a press release on Thursday.

Developing a functioning vascular system in organoids has so far been a significant challenge. This new cultivation method could, for instance, be used in pharmaceutical research.

Organoids are three-dimensional cell structures grown for example from stem cells, that resemble the structure and function of real organs. Introducing a vascular system into organoids is crucial for simulating authentic physiological functions and enabling their effective use in medical research.

The study, which was recently published, focused on kidney organoids, where vascularisation has traditionally been highly challenging with existing methods.

“Especially in the study of organs that filter blood, like the kidneys, it is essential for organoids to develop a functional vascular network. Current laboratory techniques have only been able to partially achieve vascularisation in kidney organoids,” said Seppo Vainio, Professor of Developmental Biology at the University of Oulu.

In this new technique, researchers first utilised the chorioallantoic membrane (CAM) of a chicken embryo and then a so-called lab-on-a-chip device.

“When grown on the chicken embryo membrane, blood vessels not only develop but also connect to the chicken's circulatory system for oxygen supply. This creates a strong blood flow through the organoid, which further supports its growth. A key breakthrough of this technique is that the vascularised organoids can also be transferred onto an artificial growth platform while retaining their functional vascular network,” Vainio added.

Traditionally, the development of organoids has relied on animal models. The new method developed by researchers could reduce the need for animal testing and enable longer-term studies, such as drug testing and the further advancement of tissue engineering technologies.

Vascularised organoids are particularly valuable in disease modelling and pharmaceutical research because they closely replicate the function of actual organs.

The new technique opens possibilities for studying diseases such as kidney disease, cancer, diabetes, and hypertension.