Effect of SOD1 overexpression on age- and noise-related hearing loss.

Reactive oxygen species (ROS) have been implicated in hearing loss associated with aging and noise exposure. Superoxide dismutases (SODs) form a first line of defense against damage mediated by the superoxide anion, the most common ROS. Absence of Cu/Zn SOD (SOD1) has been shown to potentiate hearing loss related to noise exposure and age. Conversely, overexpression of SOD1 may be hypothesized to afford a protection from age- and noise-related hearing loss. This hypothesis may be tested using a transgenic mouse model carrying the human SOD1 gene. Contrary to expectations, here, we report that no protection against age-related hearing loss was observed in mice up to 7 months of age or from noise-induced hearing loss when 8 week old mice were exposed to broadband noise (4-45 kHz, 110 dB for 1 h). Mitochondrial DNA deletion, an index of aging, was elevated in the acoustic nerve of transgenic mice compared to nontransgenic littermates. The results indicate the complexity of oxidative metabolism in the cochlea is greater than previously hypothesized.

Split-face double-blind study comparing the onset of action of onabotulinumtoxinA and abobotulinumtoxinA.

OBJECTIVE: To report and discuss the outcome of a prospective, internally controlled, randomized, double-blind, split-face study comparing the onset of action of 2 commercially available botulinum neuromodulators. METHODS: Ninety individuals with moderate-to-severe lateral orbital rhytids were treated with onabotulinumtoxinA, 10 U, and abobotulinumtoxinA, 30 U, for the treatment of lateral orbital rhytids. Participants were assessed live with a validated 5-point photographic scale before treatment and on days 2, 4, and 6 after treatment. Photographs were taken at each encounter. Statistical analysis was applied to evaluate for any significant difference in onset of action between the 2 products. RESULTS: AbobotulinumtoxinA and onabotulinumtoxinA demonstrated statistically significant change from baseline at day 2 in the treatment of lateral orbital rhytids at maximal contraction and rest when evaluated independently by investigator and participant (P.001). Also at day 2, the improvement with abobotulinumtoxinA was better than that with onabotulinumtoxinA for the primary end point of maximal contraction graded by the investigator, although this did not reach statistical significance (P=.21); by day 4, the greater improvement achieved with abobotulinumtoxinA reached statistical significance (P=.02) and remained superior at day 6 (P=.02). The primary findings were strengthened by similar results in the secondary end points of patient self-grade at maximal contraction and at rest and of investigator grade at rest. CONCLUSIONS: In conclusion, both abobotulinumtoxinA and onabotulinumtoxinA achieved statistically significant onset of action at day 2. This improvement was seen in all end points, with abobotulinumtoxinA demonstrating a trend toward greater improvement than onabotulinumtoxinA at day 2 and a statistically significant greater improvement at days 4 and 6 when looking at maximal contraction.

An internally controlled, double-blind comparison of the efficacy of onabotulinumtoxinA and abobotulinumtoxinA.

OBJECTIVE: To compare 2 commercially available botulinum neuromodulators in a randomized, double-blind, split-face study. METHODS: Ninety patients were treated with 10 U of onabotulinumtoxinA and 30 U of abobotulinumtoxinA for the treatment of lateral orbital rhytids. Patients were assessed live with a validated 5-point photographic scale prior to treatment and at 30 days. Patients were also photographed at each visit. RESULTS: AbobotulinumtoxinA demonstrated a statistically significant advantage compared with onabotulinumtoxinA in the treatment of lateral orbital rhytids at maximal contraction, as evaluated independently by the investigator (P = .01) and patient (P = .03). AbobotulinumtoxinA was also favored by the patient over onabotulinumtoxinA 67% of the time. While abobotulinumtoxinA seemed to treat lateral orbital rhytids better at rest, as evidenced by the data and photographs, this difference was not statistically significant (P = .42). CONCLUSIONS: AbobotulinumtoxinA offers superior efficacy in the treatment of lateral orbital rhytids compared with onabotulinumtoxinA. Further studies are needed to compare the 2 products in different muscle groups and for other indications.