Has gene therapy for ALS arrived?

Intraspinal injection of human umbilical cord blood-derived cells is neuroprotective in a transgenic mouse model of amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is characterized by progressive degeneration of motor neurons in the spinal cord, brain stem and motor cortex and has only marginal therapeutic options. Adult stem cells have recently come into the focus of neurological research. While replacement of motor neurons by stem cells currently appears not feasible, there is evidence that non-neuronal cells can be neuroprotective.

OBJECTIVE

Therefore, we evaluated the effects of direct intraspinal administration of human umbilical cord blood cells in a G93A transgenic mouse model of ALS before (day 40) and after symptom onset (day 90).

METHODS

Treatment effects were assessed by survival analysis, behavioral tests, histological and biochemical analyses.

RESULTS

Treatment at early stages increased survival, led to significant improvements in motor performance and significantly reduced motor neuron loss and astrogliosis in the spinal cord. Interestingly females tended to respond better to treatment than males.

CONCLUSION

This study confirms the neuroprotective potential of human umbilical cord blood cells and encourages further investigations.

Intramedullary spinal cord implantation of human CD34+ umbilical cord-derived cells in ALS

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder with marginal therapeutic options. Degeneration of motor neurons in the primary motor cortex, brainstem and spinal cord lead to rapidly progressive paralysis and finally to death due to respiratory failure. As pharmacological therapies have failed to provide sufficient neuroprotective effects in ALS, transplantation of stem or progenitor cells is considered a promising treatment strategy. Cell transplantation approaches in ALS mainly aim to generate a neuroprotective environment for degenerating motor neurons by transplantation of non-neuronal cells, rather than to replace lost motor neurons. We present a 63-year-old male patient suffering from ALS who underwent intramedullary thoracic spinal cord implantation of human CD34(+) umbilical cord-derived haematopoietic progenitor cells with a three-year follow up after transplantation.

Strategic approaches to developing drug treatments for ALS

Significant progress in understanding the cellular mechanisms of motor neuron degeneration in amyotrophic lateral sclerosis (ALS) has not been matched with the development of therapeutic strategies to prevent disease progression. The multiple potential causes and relative rarity of the disease are two significant factors that make drug development and assessment in clinical trials extremely difficult. We review recent progress in promoting therapeutics into clinical trials and highlight the value of moderate throughput screening for the acceleration and improvement of drug design.

Gene-based treatment of motor neuron diseases

Motor neuron diseases (MND), such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA), are progressive neurodegenerative diseases that share the common characteristic of upper and/or lower motor neuron degeneration. Therapeutic strategies for MND are designed to confer neuroprotection, using trophic factors, anti-apoptotic proteins, as well as antioxidants and anti-excitotoxicity agents. Although a large number of therapeutic clinical trials have been attempted, none has been shown satisfactory for MND at this time. A variety of strategies have emerged for motor neuron gene transfer. Application of these approaches has yielded therapeutic results in cell culture and animal models, including the SOD1 models of ALS. In this study we describe the gene-based treatment of MND in general, examining the potential viral vector candidates, gene delivery strategies, and main therapeutic approaches currently attempted. Finally, we discuss future directions and potential strategies for more effective motor neuron gene delivery and clinical translation.