Human bone marrow synthesised in lab

Artificial bone marrow that can continuously make red and white blood cells has been synthesised in a lab for the first time. This could lead to simpler pharmaceutical drug testing, closer study of immune system defects and a continuous supply of blood for transfusions.

To determine whether the substance behaves like real bone marrow, the scientists implanted it in mice with immune deficiencies. They produced human immune cells and blood vessels grew through the substance. 

Cancer-fighting chemotherapy drugs can strongly suppress bone marrow function, leaving the body more susceptible to infection. 

The new artificial marrow could allow researchers to test how a new drug at certain potencies would affect bone marrow function, said Nicholas Kotov, co-author of the study and professor in University of Michigan departments of chemical and bio-medical engineering.

"This could assist in drug development and catch severe side effects before human drug trials," he said. 

The substance grows on a 3-D scaffold that mimics the tissues supporting bone marrow in the body, 

Kotov and Joan Nichols, professor at the University of Texas, collaborated on many aspects of the project.

"This is the first successful artificial bone marrow," Kotov said. "It has two of the essential functions of bone marrow. It can replicate blood stem cells and produce B cells. The latter are the key immune cells producing antibodies that are important to fighting many diseases."

Blood stem cells give rise to blood as well as several other types of cells. B cells, a type of white blood cell, battle colds, bacterial infections, and other foreign or abnormal cells including some cancers. 

Bone marrow is a complicated organ to replicate, Kotov said. Vital to the success of this new development is the 3-D scaffold on which the artificial marrow grows. This lattice had to have a high number of precisely-sized pores to stimulate cellular interaction. 

The scaffolds are made of a transparent polymer that nutrients can easily pass through. To create the scaffolds, scientists moulded the polymer with tiny spheres ordered like billiard balls. Then, they dissolved the spheres to leave the perfect geometry of pores in the scaffold.

The scaffolds were then seeded with bone marrow stromal cells and osteoblasts, another type of bone marrow cell, said a Michigan university release. The findings were published online in Biomaterials.

"The scaffold for this work had to be designed from scratch closely mimicking real bone marrow because there are no suitable commercially available products," Kotov said.