MIT scientists have developed a groundbreaking technique to grow artificial blood vessels, marking a significant advancement in tissue engineering. This innovative approach, detailed in the Proceedings of the National Academy of Sciences, utilizes mechanical stretching to enhance the growth of new capillary-like sprouts, offering a promising solution to the challenge of oxygen and nutrient delivery in engineered tissues. The research introduces a vessel-on-a-chip platform that employs magnets to apply controlled strain within a three-dimensional tissue model, providing researchers with precise control over the growth direction, strength, frequency, and duration of stretching.
The device, smaller than a postage stamp, features a central hollow channel lined with human endothelial cells, which naturally form blood vessels. By embedding a magnetic actuator within a collagen gel, the researchers can stretch the vessel wall, triggering the growth of new sprouts. The system's motorized three-axis control allows for dynamic adjustments, enabling the researchers to study the impact of different strain levels and directions on vessel growth.
The study revealed that mechanical stretching significantly increases the number of new capillaries, with 5% dynamic strain producing the highest sprouting. Interestingly, the direction of stretching also plays a crucial role, with sprouts growing along the same line as the actuation axis. This finding highlights the importance of mechanical cues in guiding vessel growth, offering a new approach to fabricating organized blood vessel networks within engineered tissues.
One of the key insights from this research is the role of PIEZO1, a gene that controls a pressure-sensitive ion channel in cell membranes. By suppressing PIEZO1 in endothelial cells, the researchers found that the increase in sprouting was reduced, indicating its contribution to strain-induced vessel growth. However, the barrier strengthening response remained intact, suggesting the involvement of other force-sensing pathways.
The practical implications of this work are far-reaching. By precisely guiding small blood vessels, researchers can overcome a significant barrier in tissue engineering, enabling the creation of fine networks with controlled geometry. This magnetic platform offers a novel way to add physical instructions after tissue growth has begun, allowing for dynamic adjustments and the guidance of vessels through three dimensions.
Looking ahead, the team plans to incorporate additional cell types and flowing blood to better replicate native circulation. They are also exploring the potential of mechanically patterned vessels to enhance engineered muscle function. If successful, this approach could lead to the development of thicker, better-supplied implants and more realistic laboratory models for studying diseases involving abnormal blood vessel growth.
In conclusion, MIT's breakthrough in artificial blood vessel growth is a significant step forward in tissue engineering. It opens up new possibilities for creating functional, implantable tissues and offers a fresh perspective on the role of mechanical cues in vascular development. As the research progresses, we can expect to see exciting advancements in the field, bringing us closer to realizing the dream of engineered tissues that can restore function after debilitating disease or injury.
