Biepharospasm, hemifacial spasm and other diseases involving forceful, uncontrolled muscle spasms of the face and neck are extremely debilitating, often causing affected persons to withdraw from social and economic activities. Indirect treatment with orally administered medications is often accompanied by unacceptable side effects. Surgical treatments are costly and often unsatisfactory. Current medical treatment involves the injection of botulinum toxin into the affected muscles. While usually effective, this treatment provides only temporary relief. We are developing a novel permanent, non-surgical treatment for these diseases. Doxorubicin (DXN), a potent anti-metabolic and anti-mitotic cancer drug, is injected directly into the eyelids. In laboratory studies injection of DXN results in a loss of up to 70% of the muscle fibers in the orbicularis oculi muscle. This muscle loss is permanent, with no further changes in muscle fiber number after one month. In the first patient clinical trial, several patients have now gone over a year with significant relief from their muscle spasms and without requiring further treatment. One problem with the current protocol is that the maximal relief of muscle spasms requires three sets of injections at the maximal safe dose, and with each injection the possibility of skin ulceration at the injection site increases. We will examine strategies to maximize the amount of muscle within the eyelid removed by DXN chemomyectomy and minimize the unwanted side effects of direct injection. We will combine injections of DXN with agents known to increase its cytotoxicity. These include cyclosporin, calmodulin antagonists, calcium channel blockers, other anthracycline compounds, and drugs that deplete glutathione synthetase. Preliminary data suggests that these adjunctive protocols can significantly increase muscle loss. We also will determine the time course of muscle satellite (stem) cell activation after non-permanent injury to the orbicularis oculi muscle. Next we will inject DXN at the time of maximal satellite cell activation after a previous injury. by minimizing muscle regeneration we may potentiate the anti-mitotic effects of the doxorubicin and increase muscle loss. We will determine in the orbicularis oculi muscle the concentration of enzymes known to protect against free oxygen radicals, because the susceptibility of muscle to injury may be increased by using drugs that selectively deactivate these enzymes or increase the formation of free oxygen radicals after doxorubicin injection. Conversely topical vitamin E ointment will be tried as a skin protectant. We will determine how long DXN remains in the eyelid after injection. This will help us to determine the best time for subsequent injections should they prove necessary. We will determine whether local DXN injections result in its systemic spread. In year 5, we will use monkeys to help us select and test the best treatment alternatives to use in the ongoing clinical trial of DXN chemomyectomy. The successes in the laboratory have rapidly carried over into the clinical trial now in progress of this novel treatment protocol. These studies will allow us to develop the most clinically effective and cost effective treatment for these patients.
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