MIT's "living drug factories" produce insulin from inside the body
For type 1 diabetics, regular injections of insulin are an unfortunate reality of life, necessary to keep their blood-sugar levels in check in lieu of a healthy pancreas. Scientists at MIT have developed a new type of implantable cell that could handle the heavy lifting by overcoming rejection by the host’s immune system to go on producing the key hormone from within the body.
For the last couple of decades, a relatively small amount of diabetics have benefited from what’s known as pancreatic islet cell transplantation. These are the cells that produce insulin in a functional pancreas and by implanting them into sufferers of diabetes, they can take on their traditional role and negate the need for regular insulin injections.
The reason this form of therapy isn’t used more widely is that the great majority of recipients experience complications, as their immune system mistakes the transplanted cells for dangerous invaders and goes on the attack. Drugs that suppress this immune response are one solution, but they invite their own risks such as vulnerability to infection or more serious side effects.
So getting pancreatic islet cells to survive transplantation and function as normal is seen as a key objective by researchers in the field. Converting the patient's own liver cells into islet cells, wrapping them in seaweed-based capsules and organizing them into clusters are just a few of the ways the process may be improved, and now scientists at MIT have come up with another.
The technology involves encapsulating the cells in a protective shell made from a silicon-based elastomer, combined with a porous membrane. These pores are large enough that nutrients, oxygen and insulin can move freely through the membrane, but small enough to keep out immune cells that seek to attack the cell.
The team drew up some experiments to test the viability of the technology, enlisting diabetic mice and implanting them with islets packed inside the protective shells. The technology maintained healthy blood glucose levels in mice for more than 10 weeks.
Another experiment involved human embryonic kidney cells that had been engineered to produced EPO, the hormone that drives red blood cell production. These encapsulated cells survived after transplantation in mice for more than 19 weeks, leading to an increase in red blood cell count throughout.
Taking things one step further, the team found the encapsulated cells could be triggered by certain drugs to produce certain proteins. In one experiment, the scientists were able to have the cells only produce EPO once the mice had been administered the drug doxycycline, suggesting the technology could serve as a kind of “living drug factory” that offers on-demand hormones and proteins as needed.
While team is currently focused on using the technology to treat diabetics and improve the viability of transplanted islet cells, they hope it could eventually serve as a valuable tool to treat any kind of chronic disease.
“The vision is to have a living drug factory that you can implant in patients, which could secrete drugs as-needed in the patient,” says Daniel Anderson associate professor of chemical engineering and senior author of the study.
The research was published in the journal Nature Biomedical Engineering.