A team of researchers in Spain is seeking a new technique for reducing the technical hurdles involved with microencapsulating pancreatic islets when treating Type 1 diabetes.
Type 1 diabetes contributes to 10% of the total of cases of diabetes worldwide, mainly in young people and is regarded as a growing health risk.
Type 1 diabetes is characterized by the self-immune destruction of the pancreatic cells that produce insulin (pancreatic islets), which leads to severe insulin deficiency and which is followed by the raising of blood glucose levels.
Right now, the therapy based on insulin injections is the treatment applied in Type 1 diabetic patients. However, in addition to the medical complications this means in the long term, this treatment requires multiple daily measurements of blood glucose and the lifelong sub-cutaneous administration of insulin.
Alternatively, there is a new treatment on the horizon: The transplant of isolated pancreatic islets from donors to provide a fresh source of insulin-producing cells capable of meeting insulin requirements in accordance with blood glucose levels in patients with Type 1.
One of the drawbacks of islet transplants, according to Dr. Albert Espona-Noguera, one of the authors of the study, is the long-term use of immunosuppressant drugs to prevent the immune rejection of the transplanted islets.
“These drugs lower the patient’s defenses and entail serious medical complications,” explains Espona-Noguera.
To avoid this problem, he explains the pancreatic islets can be isolated from the patient’s immune system by means of microencapsulation techniques in which the islets are encapsulated in microcapsules made of biocompatible (non-toxic) materials.
“Among the many materials used in cell microencapsulation, alginate is the most widely used one,” says Espona-Noguera. “This natural polymer has excellent properties for biomedical applications as it offers high compatibility and low toxicity.”
However, the novel microencapsulation technique has various technical obstacles that are hampering its clinical application.
“A crucial problem is the high number of empty microcapsules generated during the process to microencapsulate the islets, which leads to a large increase in the volume of microcapsules to be implanted, and which in turn may increase the host’s immune reaction following implantation,” says Espona-Noguera.
Image of some microencapsulated islets. Credit: Albert Espona-Noguera. UPV/EHU.
An Innovative System
In order to avoid the high number of empty microcapsules, the researchers have come up with an innovative approach for purifying the microencapsulated islets in order to reduce the implant volume by separating the microencapsulated islets from the empty microcapsules.
“We have developed a system to magnetically separate the microcapsules and which combines different technologies: magnetic nanoparticles and a microfluidic chip, in other words, a chip with channels of micrometric size produced by means of 3D printing techniques and which contains strategically placed magnets,” added Espona-Noguera. “To separate the microcapsules, the pancreatic islets are put into contact with magnetic nanoparticles, thus providing them with magnetic properties.”
After that, the islets are microencapsulated, thus obtaining capsules containing magnetic islets and non-magnetic empty capsules.
When the microcapsules are pumped through the chip’s microchannels, the magnets move the magnetic capsules towards the exit microchannel, while the non-magnetic empty ones make their way through another exit microchannel.
“That way we are able to eliminate the empty capsules and, as a result, we reduce the volume of the therapeutic microcapsule implant,” explains Espona-Noguera.
The great purification efficiency of this magnetic separation system has enabled researchers to lower the implant volume by nearly 80%, thus reducing the complications arising out of the implanting of large volumes of microcapsules and providing an alternative Type 1 diabetes treatment.
In addition to this innovation, researchers studied the functionality of the purified implants in diabetic animal models.
“We saw that following subcutaneous implanting of the microencapsulated islets in diabetic animals, the blood glucose levels returned to normal levels for nearly 17 weeks,” Espona-Noguera added.
The research has been published in International Journal of Pharmaceutics.
The University of The Basque Country.
- The University of The Basque Country. A new system for treating type 1 diabetes mellitus. (2019, May 10). Retrieved: https://www.eurekalert.org/pub_releases/2019-05/uotb-ans051019.php