本帖最後由 goodcat1111 於 2009-3-29 15:01 編輯
作者：Bob Roehr
出處：WebMD醫學新聞
March 17, 2009(加州舊金山) —根據美國皮膚科學會第67屆年會中發表的報告，微調光動力治療與光敏感劑併用，可改善痤瘡之治療。
耶魯大學醫學院教授Macrene Alexiades-Armenakas博士解釋，單用藍光治療進行一系列治療，獲得25%至52%的痤瘡改善；但問題是，需要的治療次數太多，且效果只屬中等，也常見復發。
單用紅光或者併用藍光，獲得的反應相似，但併用兩種雷射光治療可使反應率幾乎加倍；Alexiades-Armenakas博士表示，此先驅研究的目標是，減少治療次數到一或兩次，但增加痤瘡清除率；這可以節省病患的時間與花費。
本研究包括10名對傳統治療無效的輕微到嚴重囊腫性痤瘡病患，這些病患使用局部的光敏感劑5-aminolevulinic acid (ALA)治療，之後靜候1小時；塗抹麻醉乳膏，使用非指定適應症的藍光與紅光雷射— 1450-nm雷射二極體與脈衝式染料雷射。
Alexiades-Armenakas博士表示，初步結果顯示，每次治療有較高的痤瘡清除率，毛孔縮小，產生的皮脂也較少。
控制組是4名以傳統全身或局部治療、或雷射治療但無ALA光動力治療的病患；全部都沒有達到完整的痤瘡清除率。
她指出，病患使用光照治療前後，不只戲劇性地清除痤瘡囊腫，而且也改善了皮膚紋理，比單用任一種雷射有相當顯著的改變。
Alexiades-Armenakas博士向Medscape Dermatology表示，脂質對波長1450-nm的光線有相當高的吸收性，所以皮脂毛囊的吸收率相當高。這種雷射降低皮脂腺油脂的作用幾乎與使用isotretinoin相當，且可針對痤瘡。
脈衝式染料雷射的作用方式與細胞凋零機轉類似，對於皮膚上層的血管有獨立效用。我們必須記住，痤瘡是一種發炎疾病；有免疫系統之要素。Alexiades-Armenakas博士相信，這種方法可降低目標區引起發炎免疫反應的細胞數量，減輕此一過程。
哈佛大學醫學院研究者Alexa Boer Kimball醫師表示，併用現有的介入方式來改善反應與病患耐受度是不錯的方向；本研究對此結果有幫助。
這篇先驅研究沒有接受商業資助。Alexiades-Armenakas博士以及 Kimball 醫師宣告沒有相關財務關係。
美國皮膚科學會(AAD)第67屆年會：發表於2009年3月8日。
AAD 2009: Combination Laser and Photosensitizer Improve Acne Treatment
By Bob Roehr
Medscape Medical News
March 17, 2009 (San Francisco, California) — Fine-tuning the combined use of photodynamic therapy and photosensitizers can improve treatment for acne, according to a report here at the American Academy of Dermatology 67th Annual Meeting.
Yale University School of Medicine professor Macrene Alexiades-Armenakas, MD, PhD, explained that "blue-light therapy alone results in a 25% to 52% acne improvement rating following a series of treatments. But the problem is that excessive numbers of treatments have been required, the effects have been modest, and recurrences are common."
Red light alone or in combination with blue light has similarly resulted in a modest response, although combined treatment with the 2 lasers has almost doubled the response rate. The goal of this pilot study "was to further boost the acne clearance rate while decreasing the number of treatments to 1 or 2," Dr. Alexiades-Armenakas said. This limits the time and cost to patients.
The study involved 10 patients with mild to severe cystic acne resistant to traditional treatments. Patients were treated with the photosensitizer topical 5-aminolevulinic acid (ALA) and allowed to incubate for 1 hour. Numbing cream was applied, and both blue- and red-light lasers — 1450?nm diode laser and the pulse-dye laser — were used off label.
"The preliminary results show a higher clearance rate of the acne per treatment, decreased pore size, and lower sebum production," Dr. Alexiades-Armenakas said.
A control group of 4 patients was treated with conventional systemic or topical therapy, or with lasers, but without ALA photodynamic therapy. None of them achieved complete clearance of their acne.
Using before and after photos of patients, she noted "not just a dramatic clearing of the acne cysts," but also an improvement in skin texture that is "much more dramatic" than occurs with the use of either laser alone.
"The 1450-nm wavelength is very highly absorbed in lipids, so there is a great deal of absorption in the sebaceous follicle," Dr. Alexiades-Armenakas explained to Medscape Dermatology. The action of this laser shrinks the oil glands in much the same way as isotretinoin does. "It gets to the target of acne."
The pulse-dye laser works in a similar manner and also through a mechanism of apoptosis. "There is an independent effect on the blood vessels in the upper layer of the skin. We must remember that acne is an inflammatory disease; there is an immune-system component." Dr. Alexiades-Armenakas believes that the procedure reduces the number of cellular targets that stimulate the inflammatory immune response, dampening that process.
Harvard University Medical School researcher Alexa Boer Kimball, MD, said that combining existing interventions is a good way to improve response and patient tolerability. This study is a useful addition toward that end.
The pilot study did not receive commercial funding. Dr. Alexiades-Armenakas and Dr. Kimball have disclosed no relevant financial relationships.
American Academy of Dermatology (AAD) 67th Annual Meeting: Presented March 8, 2009. |
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