Bioengineers have achieved a groundbreaking feat by constructing a human bone marrow 'blood factory' entirely in a lab, marking the first time in bioengineering. This remarkable achievement, accomplished by researchers from Switzerland's University of Basel and University Hospital Basel, could significantly reduce the reliance on animal testing in various research fields, particularly blood cancer research and drug development. The model, crafted using exclusively human cells, aims to replicate the intricate cellular environment of the human bone marrow, a crucial component of our body's blood production system. Often referred to as the 'blood factory', bone marrow is a complex tissue that produces billions of cells daily, comprising specialized components such as bone cells, blood vessels, nerves, and immune cells. It's organized into niches, with the endosteal niche, located near the bone surface, playing a vital role in normal blood formation and contributing to the development of resistance to therapies in blood cancers. Current research methods, relying on animal models or oversimplified cell cultures, fall short in accurately representing the full cellular complexity of the human bone marrow and the endosteal niche. To address this challenge, the researchers developed a new model using a supportive scaffold and specialized human cells. The foundation of this construct was an artificial bone structure made of hydroxyapatite, a natural mineral found in bones and teeth. Human cells, reprogrammed into pluripotent stem cells using molecular biology techniques, were introduced into this scaffold. These versatile stem cells, once developed, could produce all the necessary specialized cell types required for the marrow, based on the specific signals they received within the engineered environment. The researchers embedded the stem cells within the artificial bone structure and used targeted processes to create various bone marrow cell types. The resulting three-dimensional construct, measuring 8 mm in diameter and 4 mm in thickness, closely mimics the human endosteal niche and sustained human blood formation in the laboratory for weeks. This breakthrough system offers a more accurate understanding of human biology, as Professor Ivan Martin highlights, complementing animal studies in the study of blood formation in both healthy and diseased conditions. However, the current model size may be too large for parallel testing of multiple drugs and doses, necessitating miniaturization. The ultimate goal is to create personalized treatment plans for blood cancer patients by generating individual bone marrow models using their cells. Researchers can then test various therapies in vitro to determine the most effective treatment for each patient. While significant progress has been made, further development is required to reach this goal. The findings, published in the journal Cell Stem Cell, represent a crucial step forward in bioengineering, offering a more ethical and accurate approach to research and drug development.
