Clemastine in remyelination and protection of neurons and skeletal muscle after spinal cord injury

Spinal cord injuries affect nearly five to ten individuals per million every year. Spinal cord injury causes damage to the nerves, muscles, and the tissue surrounding the spinal cord. Depending on the severity, spinal injuries are linked to degeneration of axons and myelin, resulting in neuronal impairment and skeletal muscle weakness and atrophy. The protection of neurons and promotion of myelin regeneration during spinal cord injury is important for recovery of function following spinal cord injury. Current treatments have little to no effect on spinal cord injury and neurogenic muscle loss. Clemastine, an Food and Drug Administration-approved antihistamine drug, reduces inflammation, protects cells, promotes remyelination, and preserves myelin integrity. Recent clinical evidence suggests that clemastine can decrease the loss of axons after spinal cord injury, stimulating the differentiation of oligodendrocyte progenitor cells into mature oligodendrocytes that are capable of myelination. While clemastine can aid not only in the remyelination and preservation of myelin sheath integrity, it also protects neurons. However, its role in neurogenic muscle loss remains unclear. This review discusses the pathophysiology of spinal cord injury, and the role of clemastine in the protection of neurons, myelin, and axons as well as attenuation of skeletal muscle loss following spinal cord injury.

Elevated axonal membrane permeability and its correlation with motor deficits in an animal model of multiple sclerosis

Background:It is increasingly clear that in addition to myelin disruption,axonal degeneration may also represent a key pathology in multiple sclerosis(MS).Hence,elucidating the mechanisms of axonal degeneration may not only enhance our understanding of the overall MS pathology,but also elucidate additional therapeutic targets.The objective of this study is assess the degree of axonal membrane disruption and its significance in motor deficits in EAE mice.Methods:Experimental Autoimmune Encephalomyelitis was induced in mice by subcutaneous injection of myelin oligodendrocyte glycoprotein/complete Freud’s adjuvant emulsion,followed by two intraperitoneal injections of pertussis toxin.Behavioral assessment was performed using a 5-point scale.Horseradish Peroxidase Exclusion test was used to quantify the disruption of axonal membrane.Polyethylene glycol was prepared as a 30%(w/v)solution in phosphate buffered saline and injected intraperitoneally.Results:We have found evidence of axonal membrane disruption in EAE mice when symptoms peak and to a lesser degree,in the pre-symptomatic stage of EAE mice.Furthermore,polyethylene glycol(PEG),a known membrane fusogen,significantly reduces axonal membrane disruption in EAE mice.Such PEG-mediated membrane repair was accompanied by significant amelioration of behavioral deficits,including a delay in the emergence of motor deficits,a delay of the emergence of peak symptom,and a reduction in the severity of peak symptom.Conclusions:The current study is the first indication that axonal membrane disruption may be an important part of the pathology in EAE mice and may underlies behavioral deficits.Our study also presents the initial observation that PEG may be a therapeutic agent that can repair axolemma,arrest axonal degeneration and reduce motor deficits in EAE mice.