Composition and method for treating congenital cytomegalovirus induced hearing loss

BACKGROUND OF THE DISCLOSURE

Field of the Disclosure

The present disclosure generally relates to method for treating congenital cytomegalovirus (cCMV) induced hearing loss. More specifically, the method includes administering a composition to the mammal, wherein the composition consists essentially of a biologically effective amount of vitamin A, vitamin E, vitamin C, a vasodilator comprising magnesium, and, optionally, a withanolide, and/or resveratrol.

Description of the Related Art

Congenital cytomegalovirus (cCMV) is the most common infectious cause of sensorineural hearing loss (SNHL). With a prevalence of approximately 0.5%, it is estimated that 20,000 congenitally infected neonates are born in the U.S. annually. Almost 400 children die each year from this disease, and approximately 7,000 develop permanent disabilities. The most common permanent disability is hearing loss. It is estimated to account for at least 20% of SNHL in young children. More children are affected by cCMV than by other, better-known childhood conditions, such as Down syndrome, fetal alcohol syndrome, and spina bifida. This hearing loss has detrimental effects on speech and language development and incurs the major cost associated with cCMV infection, which has been estimated to be $4 billion a year.

Unfortunately, there is no effective treatment for cCMV-induced SNHL. A vaccine for cCMV infection is still lacking. Ganciclovir or its oral form, valganclovir, may attenuate the progressive nature of cCMV-induced hearing loss, but causes neutropenia, potential infertility and teratogenesis. Accordingly, there remain opportunities to develop effective methods of treating various types and causes of cCMV. There is also an opportunity to provide a composition for treating cCMV induced SNHLs.

SUMMARY OF THE DISCLOSURE

The subject disclosure provides a method of treating congenital cytomegalovirus induced hearing loss that includes the step administering a composition to the mammal, wherein the composition consists essentially of a biologically effective amount of vitamin A, vitamin E, vitamin C, a vasodilator comprising magnesium, and, optionally, a withanolide, and/or resveratrol.

DETAILED DESCRIPTION

A composition for treating congenital cytomegalovirus induced hearing loss includes components that may function through different biological mechanisms to provide an additive effect that is equal to or greater than a sum of the effect of the individual components. The composition is typically used for treating cCMV induced hearing loss, such as cCMV-induced SNHL, or preventing future progressive hearing loss. Children with initial hearing loss and cCMV have a greater than 50% chance of developing future worsening hearing. The composition may also be used as a prophylaxis in those with normal hearing and cCMV. The risk for a cCMV infected individual with initial normal hearing is approximately 10%. There is a great need to have novel agents that can prevent the development of future hearing loss in these individuals.

A method in accordance with the instant disclosure includes the step of administering a composition to a mammal that includes components that function through different biological mechanisms. In the method, the composition is typically used for treating hearing loss resulting from a cCMV infection to the inner ear of a mammal.

It has been found that one result of cCMV is that excessive free radicals form in the cochlea. The free radicals damage sensitive structures, such as hair cells, within the ear and can initiate processes that can lead to hearing loss. Vasoconstriction also occurs as a result of this infection, which leads to decreased blood flow to the inner ear and causes cell death and vascular degeneration It has been found that the underlying cause of free radical formation mediates cCMV induced hearing loss in a mouse model. Specifically, the transcription factor Nrf2 is a key regulator of several detoxifying and antioxidant genes and is activated in response to oxidative and electrophilic stress may be an important pathway in cCMV mediated hearing loss.

By removing/eliminating excess free radicals antioxidants may restore auditory function. Antioxidants act through a variety of mechanisms. The at least one scavenger of singlet oxygen and the donor antioxidant are two different classes of antioxidants that act through different mechanisms. The third antioxidant, while typically a scavenger of singlet oxygen, may be a different antioxidant that acts through a different mechanism. Scavengers of singlet oxygen reduce free radicals that contribute to inner ear pathology and thus to cCMV induced hearing loss. More specifically, by reducing free radicals, the scavengers of singlet oxygen prevent, among other damaging effects, the singlet oxygen from reacting with lipids to form lipid hydroperoxides. Lipid hydroperoxides may also play a role in causing cCMV induced hearing loss.

Even within the class of scavengers of singlet oxygen, it is believed that various antioxidants react at different sites within the body, and in particular, within cells to attenuate free radical formation. For example, one of the scavengers of singlet oxygen is typically vitamin A. In various non-limiting embodiments described herein, the terminology Vitamin A and beta-carotene may be used interchangeably. However, these embodiments in no way limit this disclosure. Vitamin A is a generic term that captures a number of molecules with a biological activity of retinol or carotenoids. Primary dietary forms of vitamin A/retinol include retinol esters and beta-carotene. The beta-carotene is made up of a polyene chain of 11 conjugated double bonds with methyl branches spaced along the polyene chain, capped at both ends by cyclohexenyl rings with 1,1,5-trimethyl substitution. Other forms of vitamin A include xanxthophylls, astaxanthin, canthxanxin, lutein, and zeaxanthin, which include a backbone of beta-carotene with hydroxyl and/or carbonyl substitution on one or more of the cyclohexenyl rings. For purposes of the subject disclosure, the vitamin A is typically present as beta-carotene. Beta-carotene is a powerful scavenger of singlet oxygen, as well as nitric oxide and peroxynitrite, and may also scavenge lipid peroxyl radicals within a lipophilic compartment of a mitochondrial membrane. Beta-carotene is an excellent scavenger of free radicals under normal physiological conditions present in most tissues.

In addition to vitamin A, other scavengers of singlet oxygen may also be present in the composition of the subject disclosure. For example, another scavenger of singlet oxygen that may be present is resveratrol. Resveratrol is more efficient at scavenging hydroxyl radicals than vitamin C, and the addition of resveratrol to the vitamins A may have additive effects.

The at least one scavenger of singlet oxygen may be present in the composition in a biologically effective amount. For purposes of the subject disclosure, the biologically effective amount may be further defined as an amount that is sufficient to produce an additive effect in a reduction in stress induced threshold shift or cCMV induced hearing loss when used in combination with other antioxidants and the magnesium. Additive effect, as used herein, refers to an effect that is equal to or greater than a sum of the effects of the individual components. In order to produce additive effect and the reduction in threshold shift or cCMV induced hearing loss, the at least one scavenger of singlet oxygen is typically present in the composition in a total amount of at least 830 international units (IU), more typically from 830 to 120,000 IU, most typically from about 2,100 to 70,000 IU for an adult dosage.

The amount of the vitamin A present in the composition is dependent upon the form of vitamin A that is used. For example, in one embodiment, vitamin A is present as retinol in an amount of at least 830 IU, more typically from 830 to 10,000 IU, more typically from 2,100 to 10,000 IU, most typically from 2,100 to 8,000 IU. As known in the art, a conversion of IU to weight for vitamin A (as retinol) is 3.33 IU/.mu.g. Thus, at least 830 international units (IU) of vitamin A (as retinol) is equivalent to at least 0.25 mg of vitamin A, from 830 to 10,000 IU of vitamin A (as retinol) is equivalent to from 0.25 to 3 mg of vitamin A, and from 2,100 to 8,000 IU of vitamin A (as retinol) is equivalent to from 0.63 to 2.4 mg vitamin A.

Alternatively, the vitamin A may be present in the composition as beta-carotene, as opposed to retinol. The retinol activity equivalents (RAE) for retinol conversion to beta-carotene, which is a pro-vitamin A carotenoid, is 1 mg to 12 mg. In terms of conversion of the amounts set forth above for the vitamin A present in the composition as retinol to the vitamin A present in the composition as beta-carotene, in one example, a total amount of at least 3.0 mg or at least 830 international units (IU) of vitamin A as beta-carotene, more typically from 3.0 to 180 mg or 830 to 50,000 IU vitamin A as beta-carotene, most typically from about 7.2 to 108 mg or 2000 to 30,000 IU of vitamin A as beta-carotene is typically present for an adult dosage. In another example, a total amount of at least 3.0 mg or at least 10,000 international units (IU) of vitamin A as beta-carotene, more typically from 3.0 to 36 mg or 10,000 to 120,000 IU vitamin A as beta-carotene, most typically from about 7.5 to 21 mg or 25,000 to 70,000 IU of vitamin A as beta-carotene is typically present for an adult dosage.

Specific amounts of the vitamin A present in the composition may be dependent on the body weight of the mammal. In one specific example, the amount of vitamin A present as retinol in the composition is about 0.0178 mg/kg body weight. Thus, for an average human weighing about 70 kg, the amount of vitamin A present as retinol in the composition may be about 1.25 mg. If the vitamin A is in the form of beta-carotene, in one example, the beta carotene in the composition is about 0.257 mg/kg body weight may be present in an amount of about 18 mg. In another example, the beta-carotene in the composition may be about in an amount of about 15 mg.

It is to be appreciated that, when additional scavengers of singlet oxygen such as resveratrol are present in the composition in addition to vitamin A, the total amount of scavengers of singlet oxygen may be greater than the ranges set forth above for the at least one scavenger of singlet oxygen, so long as at least one scavenger of singlet oxygen is present in the amounts set forth above. In addition, other scavengers of singlet oxygen may be used in place of vitamin A, so long as the amount of the at least one scavenger of singlet oxygen is present within the amounts set forth above. When present, the resveratrol is typically included in the composition in an amount of at least 1 mg, more typically in an amount of from 10 mg to 1500 mg, most typically in an amount of from 15 mg to 1000 mg.

The at least one scavenger of singlet oxygen tends to prevent the initial formation of lipid peroxides while the donor antioxidant tends to reduce peroxyl radicals and inhibits propagation of lipid peroxidation that contributes to inner ear pathology. More specifically, the donor antioxidant reacts with and reduces peroxyl radicals and thus serves a chain-breaking function to inhibit propagation of lipid peroxidation. As is evident from the chain-breaking function of the donor antioxidant in lipid peroxidation, the donor antioxidant functions within cell membranes. A specific donor antioxidant that is contemplated for use in the composition of the subject disclosure is vitamin E. Vitamin E is a generic term for all tocols and tocotrienol derivatives with a biological activity of alpha-tocopherol. Primary dietary forms of vitamin E include vitamin E itself and alpha-tocopherol. Trolox.RTM., a water-soluble analogue of alpha-tocopheral commercially available from Hoffman-Laroche, Ltd. of Basel, Switzerland, is a research agent that is typically used as a source of vitamin E.

The donor antioxidant is typically present in the composition, for example, in an amount of at least 75 IU, more typically from 75 IU to 2,000 IU, more typically from 150 to 1,500 IU, most typically from 150 IU to 800 IU. In another example, the donor antioxidant is present in the composition in an amount of at least 75 IU, more typically from 75 IU to 1,500 IU, most typically from 150 IU to 800 IU. As known in the art, a conversion of IU to weight for synthetic vitamin E is 0.66 mg/IU and for natural vitamin E is 0.45 mg/IU. Thus, when the donor antioxidant is synthetic vitamin E, in on example, at least 75 IU of vitamin E is equivalent to at least 50 mg of vitamin E, from 75 to 2,000 IU of synthetic vitamin E is equivalent to from 50 to 1,320 mg of vitamin E, from 150 to 1,500 IU of synthetic vitamin E is equivalent to from 100 to 1,000 mg of vitamin E, and from 150 to 800 IU of synthetic vitamin E is equivalent to from 100 to 536 mg of vitamin E. In another example, when the donor antioxidant is vitamin E, at least 75 IU of vitamin E is equivalent to at least 50 mg of vitamin E, from 75 to 1500 IU of vitamin E is equivalent to from 50 to 1000 mg of vitamin E, and from 150 to 800 IU of vitamin E is equivalent to from 150 to 600 mg of vitamin E. As with the amount and type of vitamin A, specific amounts of the vitamin E present in the composition may be dependent on the body weight of the mammal. In one specific example, the amount of synthetic vitamin E present in the composition is about 3.8 mg/kg body weight. Thus, for an average human weighing about 70 kg, the amount of vitamin E present in the composition may be about 266 mg. In another specific example, the amount of synthetic or natural vitamin E present in the composition is about 2.6 mg/kg body weight. Thus, for an average human weighing about 70 kg, the amount of vitamin E present in the composition may be about 182 mg.

In addition to the at least one scavenger of singlet oxygen and the donor antioxidant, the composition further includes the third antioxidant. While the third antioxidant may be a scavenger of singlet oxygen, the third antioxidant may also be an antioxidant that functions through a different mechanism. When the third antioxidant is a scavenger of singlet oxygen, the at least one scavenger of singlet oxygen is still present in the composition as a separate component from the third antioxidant, and is still present in the composition in the amounts set forth above for the at least one scavenger of singlet oxygen. As a result of the third antioxidant being another scavenger of singlet oxygen, the resulting composition would have at least two scavengers of singlet oxygen.

The third antioxidant is typically vitamin C, which is a scavenger of singlet oxygen and reactive nitrogen species. It is to be appreciated that, although the third antioxidant is typically vitamin C, other antioxidants may be used in place of the vitamin C, and the other antioxidants may function through different mechanisms than vitamin C. The term vitamin C applies to substances that possess antiscorbutic activity and includes two compounds and their salts: L-ascorbic acid (commonly called ascorbic acid) and L-dehydroascorbic acid. In addition to being known as ascorbic acid and L-ascorbic acid, vitamin C is also known as 2,3-didehydro-L-threo-hexano-1,4-lactone, 3-oxo-L-gulofuranolactone, L-threo-hex-2-enonic acid gamma-lactone, L-3-keto-threo-hexuronic acid lactone, L-xylo-ascorbic acid and antiscorbutic vitamin. Vitamin C is known to scavenge both reactive oxygen species and reactive nitrogen species. It can be oxidized by most reactive oxygen and nitrogen species, including superoxide, hydroxyl, peroxyl and nitroxide radicals, as well as such non-radical reactive species as singlet oxygen, peroxynitrite and hypochlorite. Vitamin C thus inhibits lipid peroxidation, oxidative DNA damage, and oxidative protein damage.

In contrast to vitamin A, which functions best under conditions present in most tissues, water-soluble vitamin C is an excellent free radical scavenger in an aqueous phase to thus reduce free radicals at a site different from that of vitamin A. More specifically, ascorbic acid functions to reduce free radicals in fluid, such as in cytoplasmic fluid and/or blood, before the free radicals reach cell membranes.

The third antioxidant is typically present, for example, in an amount of at least 4,000 IU, more typically from 4,000 to 60,000, more typically from 8,000 to 40,000 IU, most typically from 8,000 to 20,000 IU. In another example, the third antioxidant is typically present in an amount of at least 4,000 IU, more typically from 6,000 to 40,000 IU, and most typically from 8,000 to 20,000 IU. Using vitamin C as an example for converting IU to weight units for the third antioxidant, as known in the art, a conversion of IU to weight for vitamin C is 0.05 mg/IU. Thus, at least 4,000 IU of vitamin C is equivalent to at least 200 mg of vitamin C, from 6,000 to 60,000 IU of vitamin C is equivalent to from 300 to 3,000 mg vitamin C, from 6,000 to 40,000 IU of vitamin C is equivalent to from 300 to 2,000 mg, from 8,000 to 40,000 IU of vitamin C is equivalent to from 400 to 2,000 mg vitamin C, and from 8,000 to 20,000 IU vitamin C is equivalent to from 400 to 1,000 mg vitamin C. As with vitamins A and E, specific amounts of the vitamin C or other third antioxidant present in the composition may be dependent on the body weight of the mammal. In one specific example, the amount of vitamin C present in the composition is about 7.14 mg/kg body weight. Thus, for an average human weighing about 70 kg, the amount of vitamin C present in the composition may be about 500 mg.

As set forth above, the composition further includes a vasodilator. Typically, the vasodilator includes magnesium; however, the vasodilator, for purposes of the subject disclosure, may include other vasodilators in place of or in addition to magnesium, in place of or in addition to those including magnesium, or may include only magnesium or only magnesium-containing compounds. Vasodilators can be used for treating cCMV induced hearing loss. Vasodilators including magnesium prevent decreases in cochlear blood flow and oxygenation via biochemical mechanisms involving changes in calcium concentration and prostaglandins. Deficient cochlear blood flow and lack of oxygenation can contribute to cCMV induced hearing loss by causing metabolic changes in lateral wall tissues important for maintaining normal homeostasis of the inner ear, e.g. endocochlear potential, and normal transduction; and may cause cell death in sensitive hair cells within a cochlea of the ear. Vasodilators including magnesium have also been found to improve the efficacy of immunosuppressant therapy or carbogen inhalation therapy in recovery from cCMV induced hearing loss. Furthermore, it has been found that magnesium deficiency leads to increased calcium channel permeability and greater influx of calcium into cochlear hair cells and afferent nerve endings, increased glutamate release, and auditory nerve excitotoxicity, each of which play a role in health of the inner ear. Although the vasodilators are known in the art for treating cCMV induced hearing loss, the vasodilators, especially those including magnesium, exhibit an unexpected additive effect when combined with the biologically effective amounts of the at least one scavenger of singlet oxygen, the donor antioxidant, and the third antioxidant, especially when the at least one scavenger of singlet oxygen is vitamin A, the donor antioxidant is vitamin E, and the third antioxidant is vitamin C for purposes of treating noise-induced cCMV induced hearing loss. The additive effect referred to above is greater than not only the most efficacious of the components for treating inner ear pathology that causes cCMV induced hearing loss, but typically greater than the sum of the effects of each of the components for treating cCMV induced hearing loss. While vasodilators other than those including magnesium are envisioned for purposes of the present disclosure, additive effects are not observed with all vasodilators. For example, betahistine, which is another known vasodilator, does not exhibit an additive effect.

The vasodilator including magnesium typically includes a magnesium salt or magnesium salt complex and, more specifically, magnesium sulfate or magnesium citrate. Other vasodilators including magnesium that may be suitable for purposes of the subject disclosure include; magnesium acetate, magnesium aspartate, magnesium carbonate, magnesium chloride, magnesium fumarate, magnesium gluconate, magnesium glycinate, magnesium hydroxide, magnesium lactate, magnesium oxide, magnesium salicylate, magnesium stearate, and magnesium sulfate. Other representative salts include but are not limited to; hydrobromide, hydrochloride, bisulfate, nitrate, arginate, ascorbate, oxalate, valerate, oleate, palmitate, laurate, borate, benzoate, phosphate, tosylate, maleate, fumarate, succinate, taurate, tartrate, naphthylate, mesylate, glucoheptonate, lactobionate and laurylsulphonate salts.

Typically, the vasodilator is present in the composition in an amount of at least 50 mg. For example, when the vasodilator is magnesium, the magnesium is typically present in an amount of from 50 to 450 mg, most typically from 100 to 350 mg. As with vitamins A, C, and E, specific amounts of the vasodilator present in the composition may be dependent on the body weight of the mammal. In one specific example, the amount of the vasodilator including magnesium present in the composition is about 4.46 mg/kg body weight. Thus, for an average human weighing about 70 kg, the amount of the vasodilator including magnesium present in the composition may be about 312 mg. In another example, the amount of the vasodilator including magnesium present in the composition is about 2.14 mg/kg body weight. Thus, for an average human weighing about 70 kg, the amount of the vasodilator including magnesium present in the composition may be about 150 mg.

Non-limiting examples of amounts of the typical components included in the composition, along with more and most typical amounts, are summarized in Table 1 below.

TABLE-US-00001 TABLE 1 More Most Typical Typical Typical Dosage, mg/kg Component Amount Amount Amount body weight Vitamin A .gtoreq.830 IU 830-10,000 IU 2100-8,000 IU 0.0178 mg/kg Vitamin .gtoreq.830 IU 830-50,000 IU 2,000-30,000 IU 0.257 mg/kg A As beta- carotene Vitamin C .gtoreq.4,000 IU 4,000-60,000 IU 8,000-20,000 IU 7.14 mg/kg Vitamin E .gtoreq.75 IU 75-2000 IU 150-800 IU 3.8 mg/kg (synthetic) Magnesium .gtoreq.50 mg 50-450 mg 100-350 mg 4.46 mg/kg

With respect to Table 1, the amounts specified for the antioxidants and the vasodilator correlate, in terms of biological effectiveness, to amounts used for humans. Furthermore, it is to be appreciated that the biologically effective amounts of the antioxidants and vasodilator may be lower within the above ranges for children than for the average human, based on lower US recommended daily allowances and maximum intake levels for children. This is evident based on the typical dosages in Table 1 based on mg/kg.

Other non-limiting examples of amounts of the typical components included in the composition, along with more and most typical amounts, are summarized in Table 2 below.

TABLE-US-00002 TABLE 2 More Most Typical Typical Typical Dosage, mg/kg Component Amount Amount Amount body weight Vitamin A .gtoreq.830 IU 830-120,000 IU 2,100-70,000 IU -- Vitamin .gtoreq.830 IU 830-50,000 IU 2,100-5,900 IU 0.0178 mg/kg A As Retinol Vitamin .gtoreq.10,000 IU 10,000-120,000 IU 25,000-70,000 IU 0.214 mg/kg A As beta- carotene Vitamin C .gtoreq.4,000 IU 6,000-40,000 IU 8,000-20,000 IU 7.14 mg/kg Vitamin E .gtoreq.75 IU 75-1,500 IU 150-800 IU 2.6 mg/kg Magnesium .gtoreq.50 mg 50-450 mg 100-350 mg 2.14 mg/kg

With respect to Table 2, the amounts specified for the antioxidants and the vasodilator correlate, in terms of biological effectiveness, to amounts used in animal studies on guinea pigs. Furthermore, it is to be appreciated that the biologically effective amounts of the antioxidants and vasodilator may be lower within the above ranges for children than for the average human, based on lower U.S. recommended daily allowances and maximum intake levels for children. This is evident based on the typical dosages in Table 2 based on mg/kg.

In addition to the antioxidants and vasodilator, other components may also be present in the composition for treating cCMV induced hearing loss. These components may be used for treating the side effects of the antibiotic treatment also. For example, in one embodiment, the composition further includes a withanolide. Withanolides have been suggested for use in anti-inflammatory, anti-tumor, cytotoxic, and immunological applications. One example of a specific withanolide that may be included in the composition of the subject disclosure is the withanolide extracted from day lily plants. The extract is a powerful natural antioxidant which may be effective in preventing cell death in the inner ear by interrupting the cell-death pathway initiated by deafferentation of the auditory nerve. When included in the composition, the withanolide may be present in an amount of at least 10 ppm, more typically from 10 to 1000 ppm. Additional components, besides withanolides, can also be included. Typically, the composition is free of components that interfere with the biological mechanisms through which the at least one scavenger of singlet oxygen, the donor antioxidant, the third antioxidant, and the vasodilator function. The composition is also typically free of additional components that could degrade or neutralize the at least one scavenger of singlet oxygen, the donor antioxidant, the third antioxidant, and the vasodilator function when mixed therewith prior to internally administering the composition to the mammal. Those of skill in the art can readily identify such components in view of the mechanisms by which the individual components in the composition function as set forth above (e.g., components that cause vasoconstriction, various oxidizing agents, etc.).

It is also to be appreciated that, even if additional components are present in the composition that could interfere with the mechanisms by which the at least one scavenger of singlet oxygen, the donor antioxidant, the third antioxidant, and the vasodilator function, the composition described above is may still be effective for purposes of treating side effects of the antibiotic treatment. As one example, and as described in further detail below, the composition including the at least one scavenger of singlet oxygen, the donor antioxidant, the third antioxidant, and the vasodilator may be effective for treating cCMV induced hearing loss.

As alluded to above, the method of treating cCMV induced hearing loss includes the step of internally administering the composition of the subject disclosure to a mammal. The composition may be orally administered to the mammal, such as in the form of a tablet, liquid, gel, etc. Alternatively, the composition may be intravenously administered to the mammal through an IV or an injection of the composition.

For purposes of the subject disclosure, cCMV is typically associated with hearing loss as objectively measured in terms of differences in threshold shift, or through measurement of a percentage of hair cell loss. In mouse studies, cCMV induced hearing loss, as objectively measured as a change in auditory brainstem response or distortion product otoacoustic emission thresholds, is observed in the majority of animals, either transiently or prolonged, following inoculation. Reduction in cCMV induced hearing loss reflecting the efficacy of the composition for treating cCMV induced hearing loss may be measured as an average difference in threshold shift from baseline threshold sensitivity at 8, 16, and 32 kHz, as compared to an untreated control, after intracerebral inoculation with murine cCMV. Small differences in threshold shift may be associated with less cCMV induced hearing loss and greater efficacy of the composition for treating the cCMV induced hearing loss.

It is has been shown that hair cell loss correlates to threshold shift. For example, in guinea pig ears that recover from temporary threshold shift, morphological damage is limited to tips of stereocilia in a third row of outer hair cells (OHCs) whereas ears from animals with permanent threshold shift have damage to all three rows of OHCs and, in some cases, the inner hair cells (IHCs), with damage throughout the length of the stereocilia as well as the to the body of the hair cell.

In one embodiment, the composition of the present disclosure is administered systemically to the mammal within one day of inoculation in order to alleviate permanent threshold shift. It is to be appreciated that by administering the composition within one day of inoculation, treatment prior to inoculation is also contemplated through the method of the present disclosure.

Treatment within one day is most appropriate when the mammal has sustained infection to the inner ear. Ideally, the composition is administered to the mammal prior to inoculation to the inner ear. An alternative treatment would be administration in a cCMV infected child with initial normal hearing or hearing impairment to prevent future progressive hearing loss. For example, the composition may be administered after the child is diagnosed with cCMV.

After initial administration of the composition, the composition is typically administered to the mammal each day for at least seven days following the inoculation. Although excellent results have been achieved through such treatment, it is to be appreciated that other treatment regimens may also prove efficacious for purposes of the present disclosure.

In one embodiment, the composition is administered after peroxyl radical formation, which may be further defined as oxidative DNA damage and/or oxidative protein damage. In another embodiment, the composition is administered after peroxidation in the mammal and/or after formation of lipid peroxyl radicals within a lipophilic compartment of a mitochondrial membrane in the mammal. In a further embodiment, the composition is administered after vasoconstriction of blood vessels in an ear of the mammal. In still another embodiment, the composition is administered after formation of lipid peroxyl radicals within a lipophilic compartment of a mitochondrial membrane in the mammal.

EXAMPLES

To address whether Nrf2 deficiency causes susceptibility to cCMV-induced hearing loss, Nrf2-/- mice with C57BL/6 genetic background were infected with 200 pfu cCMV by intracerebral injection on post-natal day 3. Statistically significant worsening of hearing thresholds in cCMV infected Nrf2-/- mice is observed using auditory brainstem response and distortion product otoacoustic emission testing when compared to uninfected Nrf2-/- mice. Evidence of excessive ROS production is also detected using a superoxide-sensitive fluorescent probe dihydroethidium (DHE) on unfixed cochlear cryosectioned specimens. In these experiments, increased DHE fluorescence in the spiral ganglion of cCMV infected Balb/c mice 7 days after inoculation is demonstrated when compared to uninfected Balb/c mice.

Mice were administered ACE-Mg for 7 days following cCMV infection and tested for auditory function at one month of age. An amelioration of hearing loss in the ACE-Mg treated cCMV infected groups was observed when compared to untreated cCMV infected mice.

To assess the magnitude of cochlear damage caused by cCMV and whether pretreatment with ACE-Mg provides a protective effect on cochlear morphology, scanning electron microscopy (SEM) was performed on cochlear whole mounts at P30. There was a significant difference between the cCMV untreated mice and specimens from the uninfected control, and cCMV+ACE-Mg groups. In the uninfected cochlea (control), there are normally three well-defined rows of outer hair cells across the length of the basilar membrane. cCMV-infected mice exhibited substantial outer hair cell loss in the basal and apical turns of the organ of Corti. Treatment with ACE-Mg administration resulted in significantly less outer hair cell loss in all cochlear turns. These data suggest that ACE-Mg treatment produced significant partial protection of outer hair cell from cCMV infection.

All combinations of the aforementioned embodiments throughout the entire disclosure are hereby expressly contemplated in one or more non-limiting embodiments even if such a disclosure is not described verbatim in a single paragraph or section above. In other words, an expressly contemplated embodiment may include any one or more elements described above selected and combined from any portion of the disclosure.

One or more of the values described above may vary by .+-.5%, .+-.10%, .+-.15%, .+-.20%, .+-.25%, etc. Unexpected results may be obtained from each member of a Markush group independent from all other members. Each member may be relied upon individually and or in combination and provides adequate support for specific embodiments within the scope of the appended claims. The subject matter of all combinations of independent and dependent claims, both singly and multiply dependent, is herein expressly contemplated. The disclosure is illustrative including words of description rather than of limitation. Many modifications and variations of the present disclosure are possible in light of the above teachings, and the disclosure may be practiced otherwise than as specifically described herein.

It is also to be understood that any ranges and subranges relied upon in describing various embodiments of the present disclosure independently and collectively fall within the scope of the appended claims, and are understood to describe and contemplate all ranges including whole and/or fractional values therein, even if such values are not expressly written herein. One of skill in the art readily recognizes that the enumerated ranges and subranges sufficiently describe and enable various embodiments of the present disclosure, and such ranges and subranges may be further delineated into relevant halves, thirds, quarters, fifths, and so on. As just one example, a range "of from 0.1 to 0.9" may be further delineated into a lower third, i.e. from 0.1 to 0.3, a middle third, i.e. from 0.4 to 0.6, and an upper third, i.e. from 0.7 to 0.9, which individually and collectively are within the scope of the appended claims, and may be relied upon individually and/or collectively and provide adequate support for specific embodiments within the scope of the appended claims. In addition, with respect to the language which defines or modifies a range, such as "at least," "greater than," "less than," "no more than," and the like, it is to be understood that such language includes subranges and/or an upper or lower limit. As another example, a range of "at least 10" inherently includes a subrange of from at least 10 to 35, a subrange of from at least 10 to 25, a subrange of from 25 to 35, and so on, and each subrange may be relied upon individually and/or collectively and provides adequate support for specific embodiments within the scope of the appended claims. Finally, an individual number within a disclosed range may be relied upon and provides adequate support for specific embodiments within the scope of the appended claims. For example, a range "of from 1 to 9" includes various individual integers, such as 3, as well as individual numbers including a decimal point (or fraction), such as 4.1, which may be relied upon and provide adequate support for specific embodiments within the scope of the appended claims.