The Therapeutic Potential of Cell Encapsulation Technology for Drug Delivery in Neurological Disorders

Abstract

The brain can be damaged by a wide range of conditions including infections, hypoxia, poisoning, stroke, chronic degenerative disease and acute trauma. Some of the most problematic forms of brain damage are those associated with chronic neurodegenerative diseases or acute brain trauma as a result of contusive or penetrating injury. In these cases, damage results in the loss of specific populations of neurons and the development of defined psychiatric or neurological symptoms. Current treatments for these problems are designed to pharmacologically modify disease symptoms; however, no therapies are yet available that fully restores lost function or slow ongoing neurodegeneration in the brain. Many promising therapies with growth factors has been implicated in brain regeneration, repair and neuroprotection in the central nervous system produced interesting results, such as vascular endothelial growth factor (VEGF) (Spuch et al. 2010) brain derived growth factor (BDNF) (Malik et al., 2010) or nerve growth factor (NGF) (Sharma. 2010). However, the critical problem is the way to deliver, in a continuous and localized manner, and more important is to supply physiological amounts of growth factors into focus damage of the brain tissue. One interesting approach is cell encapsulation, in which engineered somatic cells are protected against immune cell mediated and antibody-mediated rejection through immobilization in a polymer matrix surrounded by a semipermeable membrane. The latter regulates the bidirectional diffusion of nutrients, allowing the controlled and continuous delivery of therapeutic proteins in the absent of immunosupression in the proper concentration and localization. Encapsulated cells offer enormous potential for the treatment of human disease. Many attempts have been made to prevent the rejection of transplanted cells by the immune system. Cell encapsulation is promising machinery for cell transplantation and new materials and approaches were developed to encapsulate various types of cells to treat a wide range of diseases. Cell microencapsulation holds promise for the treatment of many diseases by the continuous delivery of therapeutic products. The complexity of many neurological diseases needs the developing of new drugs and especially new pathways to deliver the drug at proper concentration and into the correct localization. One critical problem is the way to deliver, in a continuous and localized manner, physiological amounts of drugs. One