02 October 2008

A new approach to the gene therapy of type 1 diabetes

When developing methods of gene therapy for type 1 diabetes, the viral vector carrying the insulin gene is injected intravenously, intraperitoneal or intramuscularly. These invasive procedures can lead to infection and even death of the body. More importantly, the target cells of these methods are predominantly hepatocytes and muscle cells.

However, these cells are not endocrine. In order for them to react to glucose levels and convert proinsulin into insulin, they need to undergo additional genetic modification. One of the factors determining the success of gene therapy is the effectiveness of the therapeutic gene delivery system. Despite the fact that viral vectors accurately and efficiently embed exogenous genes into cells, this procedure can cause antiviral immune reactions.

Chinese scientists from Wuhan University, working under the guidance of Professor Yan-Chen (Yan-Cheng), offer an alternative solution to this problem. They claim that some of the endocrine cells of the gastrointestinal tract are potentially ideal target cells for gene therapy of diabetes, and the introduction of the insulin gene through the intestine is absolutely non-invasive and avoids many disadvantages of existing approaches. The optimal vector for this procedure should be biocompatible, efficient and have a modular structure, which will allow it to be modified to solve various practical and research tasks. As such a vector, the authors chose chitosan, which is an almost ideal non-viral vector.

Specially designed pCMV plasmids.Ins expressing the human insulin gene were coated with chitosan nanoparticles and injected into rats with simulated diabetes using enema and lavage (deep bowel lavage). After that, the animals were tested for fasting glucose and insulin levels in blood plasma. To confirm the expression of the human insulin gene, real-time polymerase chain reaction and Western blotting methods were used.

The procedure resulted in a significant increase in insulin levels and a corresponding decrease in glucose levels in the blood of animals. Based on the results obtained, the authors concluded that the human insulin gene coated with chitosan nanoparticles is successfully transfected and effectively expressed by cells of the gastrointestinal tract of rats with simulated diabetes.

The main advantage of the proposed method is its safety and non–invasiveness. If successfully introduced into clinical practice, it will cause minimal psychological and physical discomfort in patients.

The article by Niu et al. "Gene therapy for type 1 diabetes mellitus in rats by gastrointestinal administration of chitosan nanoparticles containing human insulin gene" is published in the World Journal of Gastroenterology.

Portal "Eternal youth" http://vechnayamolodost.ru / based on ScienceDaily – Novel Attempt Of Gene Therapy For Type 1 Diabetes Mellitus


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