- New Data Presented at Association for Research in Otolaryngology Meeting -
SAN DIEGO /PRNewswire/ -- American BioHealth Group LLC (ABG), a privately held San Diego-based company developing hearing loss prevention and treatment technology licensed exclusively from the U.S. Navy, announced today that positive pre-clinical data on that technology were presented in a poster at the Association for Research in Otolaryngology (ARO) Meeting held in Daytona Beach, Florida February 23 -27, 2003.
In the poster presentation, submitted by Army Colonel Richard D. Kopke, MD, and other researchers at DOD Spatial Orientation Center, Naval Medical Center, San Diego and the Center for Hearing and Deafness, State University of New York at Buffalo, pre-clinical data were presented demonstrating that administration of the antioxidant N-acetylcysteine (NAC) decreased acute noise-induced hearing loss (NIHL) due to loud impulse noise exposure. This new data extends previous research indicating that NAC is protective against loud continuous noise such as jet engine noise.
In the reported study, NAC, given in a basic science model before and after simulated M-16 rifle fire consisting of 150 shots over 75 seconds, reduced permanent hearing loss by over 70%. A similar reduction in damage to the cochlear hair cells was also noted. In other related research presented by the Naval Medical Center group at ARO, data were reported indicating that two key mechanisms of inner ear injury were depletion of inner ear glutathione and damage to mitochondria. Glutathione is a key inner ear antioxidant and NAC replenishes the inner ear glutathione depleted by loud noise.
Also reported by Dr. Kopke in a related presentation at the annual meeting of the National Hearing Conservation Association in Dallas, Texas just prior to the ARO meeting, the Navy group determined that a mitochondrial protectant known as acetyl-L-carnitine (ALCAR), also licensed by ABG from the U.S. Navy, effectively reduced permanent hearing loss due to acute trauma from continuous noise, both when given as prevention before the noise and when given hours later as treatment.
"Based on these and other findings, NAC and a broader family of antioxidant compounds, like ALCAR, licensed by ABG appear to be effective hearing loss protection therapies," stated David Karlman, Chairman and Chief Executive Officer of American BioHealth Group. "These compounds have now been shown to effectively prevent both acute and chronic hearing loss, as well as treat acute hearing loss, in models of various noise insults and cancer therapies. These compounds represent the only therapy that addresses all aspects of the postulated mechanisms of hearing loss due to noise, including free radical generation, glutamate excitotoxicity, glutathione depletion, mitochondrial injury, and programmed cell death.
"Currently there is no pharmaceutical product in the marketplace targeted at these indications, and our goal is to develop a series of products based on the technology that addresses this significant unmet medical need," added Karlman. "Potential clinical uses include hearing loss prevention in high-noise work and training environments and in environments where people are exposed to a combination of noise and toxins, such as military flight lines and certain industrial settings; protection against recreational noise hazards such as shooting; and treatment for acute acoustic injury as well as hearing loss due to genetic predisposition, chemotherapy treatment, and aging."
Noise-induced hearing loss is a significant unmet socioeconomic problem in industrial societies. It is estimated that 30 million individuals are exposed to injurious levels of noise each day, contributing significantly to the overall cost of hearing loss in the nation of $56B per year. In addition to loud noise of various types, many pathological conditions affecting the inner ear, such as traumatic injury, toxins, aging, infection, and some genetic conditions may be associated with the excessive production of reactive oxygen species (ROS) leading to oxidative stress. If the inner ear's own antioxidant defenses are overwhelmed injury or even death and permanent loss of the sensory cells of the inner ear occurs. This leads to permanent hearing loss and often also tinnitus, or the sensation of ringing in the ear. The technology licensed by ABG from the Navy boosts the inner ear antioxidant defenses to prevent or treat the damage caused by the toxic ROS. Preventing and treating acute injury to the cochlea or hearing organ in the inner ear may also reduce tinnitus in the acute setting. This approach has been validated in a number of other laboratories worldwide in a number of different models for hearing loss. These findings demonstrated the feasibility of reducing noise-induced hearing loss using clinically available antioxidant compounds. The recently reported research at ARO extends earlier studies to examine the capacity of the agent NAC to protect subjects in a model of impulse noise, as this stimulus simulates noise exposure in military operational environments. Clinical trials using NAC to counter noise-induced hearing loss and tinnitus are planned for the coming year in a military setting.
NAC is the active ingredient in a formulation known as Mucamist, an oral agent given to counteract liver damage in cases of acetaminophen overdose. NAC is a free radical scavenger and is a precursor to glutathione (GSH). NAC is well-absorbed and subsequently broken down into cysteine, which is taken up into cells and converted to GSH. At therapeutic doses it has few side effects. NAC is a currently FDA-approved compound, has been in clinical use over three decades with safety established through high-dose use over extended periods.
Association for Research in Otolaryngology
The Association for Research in Otolaryngology is an international association of scientists and physicians dedicated to scientific exploration among all of the disciplines in the field of otolaryngology. Research efforts involve the ear, nose, head, neck and related functions including hearing, balance, speech, taste and smell among others. A wide range of scientific approaches is represented including biochemical, physiological, behavioral, developmental and evolutionary.
American BioHealth Group
American BioHealth Group LLC (www.abgpharma.com), a clinical stage pharmaceutical company located in San Diego, California, is developing proprietary hearing loss prevention technology licensed from the United States Navy. The Company plans to make available this technology -- the first therapeutic (pharmaceutical) approach shown clinically to be effective in preventing and treating acute hearing loss -- primarily to individuals wishing to prevent hearing loss or tinnitus (ringing in the ears) and those seeking treatment after experiencing acute injury but before permanent injury is established. Leading causes of acute hearing loss are noise induced insults and toxin exposure. One in four individuals will develop a permanent hearing loss as a result of their occupational exposure to noise hazards. Noise-induced hearing loss is the most common occupational disease and the second most self-reported occupational illness or injury.
SOURCE: American BioHealth Group LLC
