Advanced Parkinson's Disease

In the course of progressive or traumatic neurological disorders, there is an irreplaceable loss of cells leading to a gradual loss of organ function. Despite limited and often ineffective attempts to self-repair, the body's neural plasticity is not sufficient to restore its lost circuitry. Classical medical therapy, which attempts to modify the biochemistry of these events, does not prevent or stop the basic progressive cell loss, but in fact may cause additional problems. Cell therapy is the most fascinating revolution in medicine currently underway. Cell therapy results from the understanding of complex molecular biology events triggering cellular division and development.

A century-old dogma attributed to the Spanish neuroscientist Cajal, stated that adult brain neurons can not multiply and repair itself. This dogma was recently refuted with the extraordinary discovery of the presence, in the human brain, of cells able to divide and differentiate. These cells, called neural stem cells, are the progenitors of most central nervous system cells. Most importantly, these cells are the basic seeds in the new field of neural cell therapy.

Parkinson's disease is a neurodegenerative disorder characterized by a profound loss of neurons in the substantia nigra, a small region in the brainstem. This cell loss results in the degeneration of the nigrostriatal dopamine system that regulates motor function. This, in turn, leads to motor dysfunction, consisting of poverty and slowness of voluntary movements, tremor, and stooped posture, rigidity, and gait disturbance. Modern knowledge on the causes of Parkinson's disease indicates that successful functional restoration can be achieved by replacing the deficient dopamine molecule in the damaged area of the brain.

Previous studies using fetal dopamine producing tissue implanted in patients with Parkinson's disease showed partial recovery, with limited reproducibility and efficacy. The major limitations of the fetal transplantation procedure were practical, ethical and there were several safety concerns related to the use of fetal tissue.

The isolation of neural progenitors (or neural-stem) cells has opened the potential for use in studies of brain repair and neurodegenerative disorders. These progenitor cells have an extended self-renewal capacity and possess the potential to give rise to all three major brain cell types. They can grow into a large number of progenitor cells in vitro and can be used as a source of newly formed cells for transplantation. Since they are cultured under specific conditions, critical events such as maturation and differentiation are precisely controlled by growth conditions. Methods have been developed to induce progenitor cells to become dopamine neurons, or several other types of neurons. These induced mature neurons can serve as an excellent source for cell replacement therapy in different clinical conditions, including Parkinson's disease.

Cell therapy for Parkinson's disease using progenitor cells differentiated into mature neurons such as dopamine neurons is currently under intense investigation. Because of the rapidly evolving nature of stem cell science and strict implementation of regulatory guidelines in the use of biological therapies, NeuroGeneration has continued to maintain its pioneering position in pursuing its clinical studies.