Surgery – Instruments – Light application
Reexamination Certificate
2000-12-07
2004-06-01
Bennett, Henry (Department: 3742)
Surgery
Instruments
Light application
C606S010000, C606S013000, C606S022000, C606S027000, C606S003000, C607S088000, C607S089000
Reexamination Certificate
active
06743222
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to a method of treating a mammalian skin disorder associated with sebaceous follicles. More particularly, the invention relates to a method of treating acne in a mammal using a beam of laser or incoherent radiation.
BACKGROUND OF THE INVENTION
There are a variety of disorders associated with sebaceous follicles (also referred to herein as sebaceous follicle disorders) known to afflict mammals, in particular, humans. The disorders usually are associated with aberrations (for example, structural or functional aberrations) of the sebaceous follicles. In humans, sebaceous follicles, although present over most of the body surface, usually are largest and most dense on the face, chest and upper back. Accordingly, sebaceous follicle disorders predominantly affect these areas of the human body.
Probably the most pervasive sebaceous follicle disorder in the United States is acne, which affects between 40 to 50 million individuals in the United States (White G M, (1998) “Recent findings in the epidemiologic evidence, classification, and subtypes of acne vulgaris,” J. AM. ACAD. DERMATOL. 39(2 Pt 3): S34-7). Acne occurs with greatest frequency in individuals between the ages of 15 and 18 years, but may begin at virtually any age and can persist into adulthood. In the 12 to 17-year old range, the incidence has been reported to be 25% (Strauss J S, (1982) “Skin care and incidence of skin disease in adolescence,” CURR. MED. RES. OPIN. 7(Suppl 2):33-45). Acne is a disorder characterized by inflammatory, follicular, papular and/or pustular eruptions involving the sebaceous follicles (Stedman's Medical Dictionary, 26
th
edition, (1995) Williams & Wilkins). Although there are a variety of disorders that fall within the acne family, for example, acne conglobata, acne rosacea, and acne vulgaris, acne vulgaris probably is the most notable and commonly known form of acne. Acne vulgaris occurs with greatest frequency in individuals between the ages of 15 and 18 years, but may begin at virtually any age and can persist into adulthood. Because acne vulgaris can lead to permanent scarring, for example, facial scarring, this form of acne can have profound and long-lasting psychological effects on an afflicted individual. Furthermore, pustule formation and scarring can occur at an age when the potential impact on an individual is greatest. As a result, enormous amounts of money (i.e., on the order of billions of dollars) are spent annually in the United States on various topical and systemic acne treatments. These treatments often are employed without the guidance or supervision of a physician.
Acne vulgaris typically results from a blockage of the opening of the sebaceous follicle. It is believed that both (i) the amount of sebum, a lipid, keratin and cellular debris containing fluid, produced and secreted by the sebaceous glands and (ii) bacteria, namely,
Propionibacterium acnes
(
P. acnes
) which metabolize lipids in the sebum, play a role in formation and development of acne vulgaris. The basic lesion of acne vulgaris is referred to as a comedo, a distension of the sebaceous follicle caused by sebum and keratinous debris. Formation of a comedo usually begins with defective keratinization of the follicular duct, resulting in abnormally adherent epithelial cells and plugging of the duct. When sebum production continues unabated, the plugged follicular duct distends. A blackhead (or open comedo) occurs when a plug comprising a melanin containing blackened mass of epithelial debris pushes up to opening of the follicular duct at the skin surface. A whitehead (or closed comedo) occurs when the follicle opening becomes very tightly closed and the material behind the closure ruptures the follicle causing a low-grade dermal inflammatory reaction. Accordingly, some comedones, for example, in acne vulgaris, evolve into inflammatory papules, pustules, nodules, or chronic granulomatous lesions. Proliferation of
P. acnes
can result in the production of inflammatory compounds, eventually resulting in neutrophil chemotaxis (Skyes and Webster (1994) Drugs 48: 59-70).
At present, acne patients may receive years of chronic topical or systemic treatments. Current treatment options include, for example, the use of topical anti-inflammatory agents, antibiotics and peeling agents, oral antibiotics, topical and oral retinoids, and hormonal agonists and antagonists. Topical agents include, for example, retinoic acid, benzoyl peroxide, and salicylic acid (Harrison's Principles of Internal Medicine, 14
th
edition, (1998) Fauci et al., eds. McGraw-Hill). Useful topical antibiotics include, for example, clindamycin, erythromycin, and tetracycline and useful systemic antibiotics include, for example, erythromycin, tetracycline, and sulphanilamides (see, for example, U.S. Pat. Nos. 5,910,493 and 5,674,539). Administration of the systemic retinoid, isotretinion, has demonstrated some success in the treatment of acne (Harrison's Principles of Internal Medicine, 14
th
edition, (1998) Fauci et al., eds. McGraw-Hill). Studies indicate that this drug decreases sebaceous gland size, decreases the rate of sebum production and/or secretion, and causes ductal epithelial cells to be less adherent, thereby preventing precursor lesions of acne vulgaris (Skyes and Webster (1994) supra). Side-effects, however, include dry mouth and skin, itching, small red spots in the skin, and eye irritation. A significant concern about oral retinoids is their possible teratogenicity (Turkington and Dover (1996) SKIN DEEP: AN A-Z OF SKIN DISORDERS, TREATMENT AND HEALTH FACTS ON FILE, Inc., New York, page 9). In addition, a variety of hormone-related, for example, corticosteroid anti-inflammatory therapies have been developed for the treatment of acne. These therapies can be expensive and most are associated with deleterious systemic or localized side-effects (Strauss (1982) “Skin care and incidence of skin disease in adolescence,” CURR. MED. RES. OPIN. 7(Suppl 2): 33-45).
Because the foregoing therapies generally do not affect the structure and/or function of sebaceous follicles associated with the disease, the treatments remain non-curative. In other words, the disorder may recur after cessation of therapy. The result can be years of chronic therapy, and potential scarring for the patient, and enormous associated health care costs.
In recent years, a variety of laser-based methodologies for treating acne have been developed. The methods generally involve the combination of laser radiation and either an exogenous or endogenous chromophore present in the target tissue so that the laser light is absorbed preferentially in the target tissue causing morphological changes to the sebaceous follicle and/or causing a reduction of sebum production. For example, U.S. Pat. No. 5,817,089 describes a laser-based method for treating acne requiring topical application of a light absorbing chromophore, for example, micron graphite particles dispersed in mineral oil, onto skin needing such treatment. Similarly, U.S. Pat. No. 5,304,170 also describes a laser-based method for treating acne in which target cells contain greater amounts of a light absorbing chromophore, for example, the carotenoid &bgr;-carotene, relative to lesser or non-pigmented surrounding cells. In the chromophore based methods it can be difficult to get sufficient chromophore in the target region to elicit selective tissue damage and the method may still damage the outer layers of the skin resulting in scarring.
SUMMARY OF THE INVENTION
The present invention addresses the foregoing problems and provides a method for treating sebaceous follicle disorders of mammalian skin, for example, human skin. The method permits treatment of the sebaceous follicle disorder while at the same time preserving surrounding skin tissue, for example, skin epidermis. The invention offers numerous advantages over existing treatment protocols. For example, the method provides a long lasting treatment which persists long after treatment has ceased. Furtherm
Durkin Anthony J.
Paithankar Dilip Y.
Bennett Henry
Candela Corporation
Dahbour Fadi H.
Testa Hurwitz & Thibeault
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