warfarin and Amyotrophic-Lateral-Sclerosis

Topics: Amyotrophic Lateral Sclerosis; Anticoagulants; Aspirin; Humans; Intracranial Arteriovenous Malformations; Meta-Analysis as Topic; Randomized Controlled Trials as Topic; Stroke; Warfarin

Humans with ALS and transgenic rodents expressing ALS-associated superoxide dismutase (SOD1) mutations develop spontaneous blood-spinal cord barrier (BSCB) breakdown, causing microvascular spinal-cord lesions. The role of BSCB breakdown in ALS disease pathogenesis in humans and mice remains, however, unclear, although chronic blood-brain barrier opening has been shown to facilitate accumulation of toxic blood-derived products in the central nervous system, resulting in secondary neurodegenerative changes. By repairing the BSCB and/or removing the BSCB-derived injurious stimuli, we now identify that accumulation of blood-derived neurotoxic hemoglobin and iron in the spinal cord leads to early motor-neuron degeneration in SOD1(G93A) mice at least in part through iron-dependent oxidant stress. Using spontaneous or warfarin-accelerated microvascular lesions, motor-neuron dysfunction and injury were found to be proportional to the degree of BSCB disruption at early disease stages in SOD1(G93A) mice. Early treatment with an activated protein C analog restored BSCB integrity that developed from spontaneous or warfarin-accelerated microvascular lesions in SOD1(G93A) mice and eliminated neurotoxic hemoglobin and iron deposits. Restoration of BSCB integrity delayed onset of motor-neuron impairment and degeneration. Early chelation of blood-derived iron and antioxidant treatment mitigated early motor-neuronal injury. Our data suggest that BSCB breakdown contributes to early motor-neuron degeneration in ALS mice and that restoring BSCB integrity during an early disease phase retards the disease process.

Topics: Amyotrophic Lateral Sclerosis; Animals; Blood-Nerve Barrier; Ferrocyanides; Humans; Immunoblotting; In Situ Nick-End Labeling; Male; Mice; Mice, Transgenic; Microscopy, Confocal; Motor Neurons; Nerve Degeneration; Point Mutation; Protein C; Real-Time Polymerase Chain Reaction; Rotarod Performance Test; Spinal Cord; Superoxide Dismutase; Superoxide Dismutase-1; Tight Junction Proteins; Warfarin

Amyotrophic lateral sclerosis (ALS) is an orphan neurodegenerative disease currently without a cure. Mutations in copper/zinc superoxide dismutase 1 (SOD1) have been implicated in the pathophysiology of this disease. Using a high-throughput screening assay expressing mutant G93A SOD1, two bioactive chemical hit compounds (1 and 2), identified as arylsulfanyl pyrazolones, were identified. The structural optimization of this scaffold led to the generation of a more potent analogue (19) with an EC(50) of 170nM. To determine the suitability of this class of compounds for further optimization, 1 was subjected to a battery of pharmacokinetic assays; most of the properties of 1 were good for a screening hit, except it had a relatively rapid clearance and short microsomal half-life stability. Compound 2 was found to be blood-brain barrier penetrating with a brain/plasma ratio=0.19. The optimization of this class of compounds could produce novel therapeutic candidates for ALS patients.

Topics: Amyotrophic Lateral Sclerosis; Animals; Enzyme Inhibitors; Humans; Magnetic Resonance Spectroscopy; Mice; Pyrazolones; Spectrometry, Mass, Electrospray Ionization; Superoxide Dismutase