David A. Becker

Stilbazulenyl nitrone, a novel antioxidant, is highly neuroprotective in focal ischemia

Azulenyl nitrones are novel chain‐breaking antioxidants with low oxidation potentials and high lipophilicity—properties favoring their efficacy as neuroprotectants. We tested the second‐generation azulenyl nitrone, stilbazunenlyl nitrone (STAZN), in focal ischemic stroke. Physiologically monitored rats received 2 hours of middle cerebral artery occlusion by intraluminal suture, resulting in substantial cortical and striatal infarcation. Neurobehavior was quantified on a standard battery, and brains were perfusion‐fixed for quantitative histopathology at 3 days. In 3 independent series, rats were treated at either 2h + 4h, or 2h + 4h + 24h + 48h, after onset of ischemia; vehicle‐treated rats received dimethylsulfoxide or saline. All animals (n = 52) developed high‐grade neurological deficits (score 11 of 12) during ischemia, which improved, in STAZN‐treated rats, within 1–1.5 h of the initial dose and fell to a median score of 3 at 72 h, compared to 8 in vehicle rats. STAZN treatment reduced mean cortical infarct volume by 64–97%, and total infarct volume by 42–72%. In over one‐half of STAZN‐treated animals, cortical infarction was virtually abolished. Regression analysis predicted that STAZN would confer ∼50% cortical neuroprotection even in the most severely affected cases. The potency of STAZN was orders‐of‐magnitude greater than other nitrones such as NXY‐059. These results suggest that STAZN has great promise for ischemic stroke. Ann Neurol 2003

A novel azulenyl nitrone antioxidant protects against MPTP and 3-nitropropionic acid neurotoxicities.

Oxidative stress plays an important role in neuronal death in neurodegenerative disorders such as Parkinsons disease (PD) and Huntingtons disease (HD). Animal models of PD or HD, produced by administration of the mitochondrial toxins 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or 3-nitropropionic acid (3NP), respectively, show increased free radical generation. Free radicals generated in biological systems can react with spin-trapping compounds, such as nitrones, to form stable adducts. In recent years, the utility of nitrones has moved beyond analytical applications and into the realm of neuroprotection as antioxidants in both brain ischemia and models of neurodegenerative diseases. In the present study, we administered a new nitrone antioxidant, stilbazulenyl nitrone (STAZN), with either MPTP or 3NP. STAZN attenuated MPTP-induced striatal dopamine depletion by 40% and showed a tendency to dose-dependent neuroprotection. STAZN dose-dependently protected against loss of tyrosine hydroxylase immunoreactive neurons in the substantia nigra pars compacta. STAZN reduced the striatal lesion volume caused by systemic 3NP administration from 44 +/- 9 to 20 +/- 6 mm(3). The lipid peroxidation marker, malondialdehyde(MDA), was significantly increased in the striatum, cortex, and cerebellum of rats after administration of 3NP. These increases were blocked by co-injection of STAZN. Our data provide further evidence that STAZN is a neuroprotective free radical spin trap, and suggest that the development of new antioxidants will broaden our therapeutic strategies for neurodegenerative diseases.

Azulenyl Nitrone Spin Traps Protect against MPTP Neurotoxicity

Azulenyl nitrones are a unique class of free radical spin-trapping compounds. We administered both a water-soluble and a lipid-soluble azulenyl nitrone to mice prior to administration of MPTP. Both compounds produced significant neuroprotection against depletions of dopamine and its metabolites measured 1 week after MPTP administration. There were no effects on MPP+ levels. These findings provide further evidence that free radical scavengers can produce significant neuroprotection against MPTP neurotoxicity.

Neuroprotective effect of STAZN, a novel azulenyl nitrone antioxidant, in focal cerebral ischemia in rats: Dose–response and therapeutic window

Stilbazulenyl nitrone (STAZN) is a potent antioxidant that, in a rat model of transient focal cerebral ischemia, confers significant enduring functional and morphological neuroprotection. This study investigated the influence of dose and time of administration on the neuroprotective effects of STAZN in the intraluminal suture model of middle cerebral artery occlusion (MCAo). Dose response: At 2 and 4 h after the onset of MCAo, animals received intravenously either STAZN (low dose=0.07 mg/kg, n=8; medium dose=0.7 mg/kg, n=9; high dose=3.5 mg/kg, n=9), an equivalent volume of vehicle (30% Solutol HS15 and 70% isotonic saline, 0.37 ml/kg, n=5) or saline (0.37 ml/kg, n=5). Only the medium dose improved scores (p<0.05) on a standardized neurobehavioral test at 1, 2 and 3 days after MCAo. Only the medium dose reduced the total infarction (51%, p=0.014) compared to controls. These results indicate that STAZN exhibits maximal neuroprotection at the 0.7 mg/kg dose. Therapeutic window: STAZN (0.6 mg/kg) dissolved in dimethylsulfoxide was given intra-peritoneally at 2 and 4 h (n=11), 3 and 5 h (n=10), 4 and 6 h (n=10) or 5 and 7 h (n=7) after the onset of MCAo. Additional doses were given at 24 and 48 h. Vehicle (dimethylsulfoxide, 2.0 ml/kg, n=6) was administered at 3, 5, 24 and 48 h. STAZN treatment initiated at 2 or 3 h after the onset of MCAo improved neurological scores (p<0.001) and reduced total infarction (42.2%, p<0.05) compared to controls.

Redox behaviour of azulenyl nitrones: fully reversible one electron oxidation by cyclic voltammetry at potentials in the range of biological antioxidants

The one electron oxidation chemistry of azulenyl nitrones 4 and 5 employing cyclic voltammetry reveals that, unlike conventional nitrone spin traps such as PBN and S-PBN, such oxidation is electrochemically and chemically reversible at potentials near or within those of important biological chain-breaking antioxidants.

Azulenyl Nitrones: Colorimetric Detection of Oxyradical End Products and Neuroprotection in the Gerbil Transient Forebrain Ischemia/Reperfusion Model

We present analytical and neuroprotective data on a unique spin trapping agent derived from a novel chemical class known as an azulenyl nitrone (AZN). Based on Colorimetric properties, AZN was used to assess the formation of free radicals in a bilateral carotid occlusion (BCO) model in gerbils by monitoring the conversion of the nitrone to the aldehyde in affected tissue. In addition, AZN was tested as a neuroprotectant in this model regarding the preservation of CA1 pyramidal cells of the hippocampus following transient ischemia/reperfusion. AZN was electrochemically oxidized to give the aldehyde using an HPLC system with on line electrochemical oxidation. The oxidation potential associated with a 50% loss of AZN occurred at about 600 mV (half-wave potential versus palladium electrode). The major product detected as AZN oxidation occurred in an aqueous methanolic medium was the corresponding azulenyl aldehyde. Oxidation of AZN was inversely related to the formation of the aldehyde. Based on this test, we considered the in vivo conversion of AZN to aldehyde to be a measurement of oxidative stress in tissue. Results show that 0.3% of hippocampal AZN was converted to aldehyde in animals treated as shams. However, in gerbils subjected to a 7-min ischemic insult plus 7-min reperfusion, the conversion rate was about 3 times higher at 1.0%. In this model, surviving CA1 hippocampal neurons were counted from gerbils that were subjected to 7 mins of BCO followed by 5 days of reperfusion. In sham animals, about 89 cells were counted in a selected field of CA1 neurons. With injury, only 27 cells on average survived (70% loss) and were counted from this selected field. Under similar conditions and AZN treatment, 57 cells survived (36% loss). We conclude, therefore, that the demonstrated neuroprotection occurs because AZN neutralizes radicals which contribute to neuronal damage following ischemia/reperfusion.

Mutant Cu,Zn superoxide dismutase in motor neuron disease.

Cu,Zn superoxide dismutase (Cu,Zn SOD) is one of several anti-oxidant enzymes which defend the cell against damage by oxygen free radicals. Mutations of the SOD1 gene encoding Cu,Zn SOD are found familial amyotrophic lateral sclerosis, a progressive and fatal paralytic disease which is caused by the death of motor neurons in cortex, brainstem and spinal cord. The disease can be reproduced in transgenic mice by expression of mutant human Cu,Zn SOD. Recent studies both in vitro and in vivo suggest that the effect of mutation is to enhance the generation of oxygen radicals by the mutant enzyme. Thus, mutation converts a protective, antioxidant enzyme into a destructive pro-oxidant form which catalyzes free radical damage to which motor neurons are uniquely vulnerable.

A peculiarly cerebroid convex zygo-dodecahedron is an axiomatically balanced "house of blues": The circle of fifths to the circle of willis to cadherin cadenzas

A bilaterally symmetrical convex dodecahedron consisting of twelve quadrilateral faces is derived from the icosahedron via a process akin to Fuller’s Jitterbug Transformation. The unusual zygomorphic dodecahedron so obtained is shown to harbor a bilaterally symmetrical jazz/blues harmonic code on its twelve faces that is related to such fundamental music theoretical constructs as the Circle of Fifths and Euler’s tonnetz. Curiously, the patterning within the aforementioned zygo-dodecahedron is discernibly similar to that observed in a ventral view of the human brain. Moreover, this same pattern is arguably evident during development of the embryonic pharynx. A possible role for the featured zygo-dodecahedron in cephalogenesis is considered. Recent studies concerning type II cadherins, an important class of proteins that promote cell adhesion, have generated data that is demonstrated to conform to this zygo-dodecahedral brain model in a substantially congruous manner.