Inhibitory effect of azelaic acid on neutrophil functions: a possible cause for its efficacy in treating pathogenetically unrelated diseases

The effect of azithromycin on reactive oxygen species in rosacea

BACKGROUND

Recent evidence suggests that inflammation in rosacea is associated with generation of reactive oxygen species (ROS) that are released by inflammatory cells. The efficacy of current therapeutic agents for rosacea such as tetracyclines and metronidazole has also been attributed to their antioxidant properties. Recently, a macrolide antibiotic, azithromycin, has been found to be an effective alternative in the treatment of rosacea.

AIM

We planned a study to evaluate the antioxidant effects of azithromycin on ROS in rosacea. We compared basal ROS concentrations measured in the facial skin of patients with rosacea with the post-treatment levels and with those of healthy controls.

METHODS

Facial skin biopsies of 17 papulopustular patients with rosacea and 25 healthy controls were taken. Rosacea patients were assigned to receive oral azithromycin 500 mg on three consecutive days each week for 4 weeks. The total number of inflammatory lesions (the sum of papules and pustules) on the face of each patient with rosacea was counted at each visit. The luminol- and lucigenin-enhanced chemiluminescence (CL) levels of patients with rosacea were measured before and after 4 weeks of treatment and compared with those of healthy controls.

RESULTS

Rosacea patients had higher ROS levels than healthy controls (P < 0.001). A statistically significant decrease of both luminol- and lucigenin-enhanced CL levels were observed in patients with rosacea after treatment with azithromycin (t = 4.602, P < 0.001; vs. t = 4.634, P < 0.001, respectively).

CONCLUSION

Rosacea patients have higher ROS levels than healthy controls. The results of our study support the antioxidant properties of azithromycin in rosacea.

Update on the genusMalassezia

Malassezia yeasts are commensals of normal human skin, but also cause pityriasis versicolor, seborrhoeic dermatitis and evidence is accumulating that they play a significant role in atopic eczema/dermatitis syndrome (AEDS; formerly atopic dermatitis). The taxonomy of the genus has changed considerably and is likely to change more in the future. Our understanding of the interaction between Malassezia and the host demonstrates that it has the paradoxical ability to both stimulate and suppress the immune response directed against it and there is a fine balance in its existence at the interface between commensalism and pathogenicity.

The treatment of melasma: A review of clinical trials

Melasma is an irregular brown or grayish-brown facial hypermelanosis, often affecting women, especially those living in areas of intense UV radiation. The precise cause of melasma remains unknown; however, there are many possible contributing factors. Because of its dermal component and tendency to relapse, melasma is often difficult to treat. The use of broad-spectrum (UVA + UVB) sunscreen is important, as is topical hydroquinone, the most common treatment for melasma. Other lightening agents include retinoic acid (tretinoin) and azelaic acid. Combination therapies such as hydroquinone, tretinoin, and corticosteroids have been used in the treatment of melasma, and are thought to increase efficacy as compared with monotherapy. Kojic acid, isopropylcatechol, N-acetyl-4-cysteaminylphenol, and flavonoid extracts are other compounds that have been investigated for their ability to produce hypopigmentation, but their efficacy, safety, or trial design indicates that the interventions would need further study before they could be recommended. Chemical peels, laser treatments, and intense pulsed light therapy are additional therapeutic modalities that have been used to treat melasma.

Pediatric rosacea

Rosacea is a condition most commonly associated with adults; however, various forms exist in the pediatric population and need to be considered when a child presents with a facial rash. Acne rosacea, steroid rosacea, granulomatous periorificial dermatitis, and other variants of rosacea are presented here and are distinguished from their numerous mimickers. Various topical and systemic therapeutic options exist for the treatment of rosacea with several adjustments and considerations that must be taken into account when treating a child.

Medical treatment of rosacea with emphasis on topical therapies

Due to the development and release of newer topical formulations, the diagnosis and treatment of rosacea has received renewed attention over the past 3-5 years both in the literature and at medical symposia. Rosacea is a very common facial dermatosis. In the US, rosacea is estimated to affect > 14 million people, predominantly adults with approximately 60% of cases diagnosed before the age of 50. A frustrating aspect of the disease is its inherent chronicity punctuated with periods of exacerbation and relative remission. A variety of subtypes have been identified which correlate with clinical presentation. Although the pathogenesis of rosacea is poorly understood, multiple topical agents are available. The efficacy of topical therapy for rosacea relates primarily to reduction in inflammatory lesions (papules, pustules), decreased intensity of erythema, a reduction in the number and intensity of flares and amelioration of symptoms, which may include stinging, pruritus and burning. The list of main topical agents utilised for the treatment of rosacea include metronidazole, sulfacetamide-sulfur, azelaic acid and topical antibiotics (clindamycin, erythromycin). Depending on the severity at initial presentation, topical therapy may be combined with systemic antibiotic therapy (e.g., oral tetracycline derivative). Newer therapeutic choices primarily involve improved vehicle formulations, which demonstrate favourable skin tolerability and cosmetic elegance.

15 % Azelainsauregel in der Behandlung der Akne. Zwei doppelblinde klinische Vergleichsstudien. Azelaic acid 15 % gel in the treatment of acne vulgaris. Combined results of two double-blind clinical comparative studies

BACKGROUND

Topical measures are still the mainstay in the therapy of mild-to-moderate acne vulgaris. Azelaic acid 20% in a cream formulation has been established as an efficacious and safe topical drug for 15 years. A new non-alcoholic hydrogel formulation containing 15% azelaic acid was clinically tested against two standard drugs--5% benzoyl peroxide (BPO) and 1% clindamycin.

PATIENTS AND METHODS

In two independent, randomized, blinded comparative trials 15% azelaic acid gel was clinically tested against 5% benzoyl peroxide (BPO) gel in 351 patients and against 1% clindamycin gel in 229 patients. The drugs were applied b.i.d. for 4 months.

RESULTS

Azelaic acid 15% gel proved to be as effective as BPO and clindamycin with median % reduction of the inflamed lesion (papules and pustules) of 70%, and 71% respectively. The azelaic acid gel was well-tolerated, the side effects (local burning and irritation) were distinctly less than with BPO but more pronounced than with clindamycin. Despite these side effects, the treatment was well-accepted by the majority of patients.

CONCLUSIONS

Azelaic acid gel is an effective topical monotherapy for mild-to-moderate acne vulgaris; its new gel form is an enrichment of acne therapy.

Rosacea: II. Therapy

Despite an incomplete understanding of the pathogenesis of rosacea, therapeutic modalities continue to expand. The principal subtypes of rosacea include erythematotelangiectatic rosacea, papulopustular rosacea, phymatous rosacea, and ocular rosacea. These phenotypic expressions are probably caused by divergent pathogenic factors and consequently respond to different therapeutic regimens. A subtype-directed approach to therapy is discussed in part II of this review. We provide an overview of the available topical, oral, laser, and light therapies in the context of these cutaneous subtypes, review the evidence that supports their use, and outline their therapeutic approach. Suggestions for future areas of study also are provided. Learning objective At the completion of this learning activity, participants should be familiar with the subtype-directed approach to therapy for rosacea including available topical, oral, laser, and light therapies.

Acute diverticulitis of the colon--current medical therapeutic management

Diverticular disease of the colon is very common in developed countries with its prevalence increasing with age, varying from < 10% in those < 40 years of age, to an estimated 50-66% of patients > 80 years of age. Diverticulitis, defined as inflammation and/or infection associated with diverticula, is the most common clinical complication of this disorder, affecting an estimated 10-25% of patients with colonic diverticula. The therapeutic measures aim at putting the intestine 'at rest', thus resolving the infection, the consequences of the inflammation and preventing or limiting complications. For patients with severe and complicated diverticulitis, ampicillin, gentamicin, metronidazole, piperacillin and tazobactam are the antibiotics successfully used in clinical practice, whereas ciprofloxacin, metronidazole and more recently, rifaximin, have been successfully used in the treatment of uncomplicated diverticular disease. Mesalazine (alone or in association with antibiotics) and probiotics are the two latest therapies for the treatment of diverticulitis which have been developed in the last few years. In fact, the combination of mesalazine and an antibiotic showed significant superiority in improving the severity of symptoms, bowel habits and in preventing symptomatic recurrence of diverticulitis than antibiotics alone, but probiotics also seem to be effective in preventing recurrence of the disease. In light of the excellent results obtained in the treatment of inflammatory bowel disease and irritable bowel syndrome, it is probable that probiotics may be the future best treatment also for mild-to-moderate uncomplicated attacks of acute diverticulitis, especially if used with salycilates.

Azelaic acid 15% gel: in the treatment of papulopustular rosacea

Azelaic acid is a naturally occurring, straight-chain dicarboxylic acid which is effective in the treatment of rosacea, presumably on account of its anti-inflammatory properties. In randomized, double-blind, multicenter studies involving patients with moderate papulopustular facial rosacea, twice-daily topical application of azelaic acid 15% gel to the face was significantly more effective than twice-daily administration of either its vehicle (two studies) or metronidazole 0.75% gel (one study) in reducing inflammatory lesion counts and erythema severity. However, neither active treatment had a clinically discernable effect on telangiectasia. In all three studies, azelaic acid 15% gel recipients experienced continuous decreases in lesion counts and erythema throughout the 12- to 15-week treatment periods. However, the effects of metronidazole 0.75% gel plateauxed after 8 weeks. In other efficacy assessments in these studies, azelaic acid 15% gel was superior to its vehicle and metronidazole 0.75% gel in both the investigators' global assessment of rosacea and the investigators' end-of-study evaluation of overall improvement, and superior to its vehicle in the patients' end-of-study evaluation of overall improvement. The most frequent treatment-related cutaneous adverse events during administration of azelaic acid 15% gel include burning/stinging/tingling and pruritus (itching); however, these events are predominantly transient in nature and mild-to-moderate in intensity.

Efficacy and safety of azelaic acid (15%) gel as a new treatment for papulopustular rosacea: results from two vehicle-controlled, randomized phase III studies

BACKGROUND

Rosacea is a common, chronic dermatosis for which safe and effective new treatment options are needed.

OBJECTIVE

The objective of these studies was to evaluate the efficacy, tolerability, and safety of a new formulation of 15% azelaic acid (15%) gel (AzA gel), for the topical treatment of moderate, papulopustular rosacea.

METHODS

Two multicenter, double-blind, randomized, parallel-group, vehicle-controlled studies were conducted using identical study designs, patient-selection criteria, and efficacy end points. Overall, 329 patients were enrolled in study 1 and 335 patients in study 2.

RESULTS

Both studies consistently demonstrated the superiority of AzA gel over vehicle in the topical treatment of moderate, papulopustular rosacea. AzA gel yielded statistically significantly higher reductions in mean inflammatory lesion count than vehicle: 58% versus 40%, study 1 (P =.0001); 51% versus 39%, study 2 (P =.0208). Significantly higher proportions of patients treated with AzA gel experienced improvement in erythema compared with vehicle gel: 44% versus 29%, study 1 (P =.0017); 46% versus 28%, study 2 (P =.0005). Using the investigator's global assessment, therapeutic success in terms of a clear, minimal, or mild final result was achieved in 61% and 62% of patients treated with AzA gel in studies 1 and 2, respectively, which was significantly superior to the result achieved with vehicle (40% and 48%, respectively) (P <.0001, study 1; P =.0127, study 2). No serious, treatment-related adverse events were reported.

CONCLUSION

The results of these 2 controlled studies demonstrate that AzA gel, used twice daily, is an efficacious, safe, and well-tolerated topical treatment for moderate, papulopustular rosacea.

Transdermal Penetration of Topical Drugs Used in the Treatment of Acne

Acne vulgaris is a very common skin disease. Most patients present with mild to moderate acne comedonica or papulopustulosa grade I-II. The first-line treatment for these cases is generally via the topical route, whereas systemic medication is indicated when higher severity grades with small nodes or scarring occur. There are several topical agents available that affect at least one of the main pathogenetic factors responsible for the development of acne: hyperseborrhoea, hyperkeratosis, microbial colonisation and inflammatory and immunological reactions. Topical retinoids have a comedolytic and anticomedogenic activity, and some of them have anti-inflammatory potency. Azelaic acid and benzoyl peroxide have a moderate to strong antibacterial effect without inducing bacterial resistance, which is becoming a significant problem with the increasing use of topical antibacterials. Topical antiandrogens may soon be available for the treatment of the pathogenetic factor hyperseborrhoea. The transdermal penetration and the resulting systemic bioavailability of the various topical agents has not been widely considered. Apart from the retinoids, which can be associated with the risk of embryotoxicity/teratogenicity, and clindamycin, which might cause pseudomembranous colitis, information on the systemic pharmacokinetics of other topical agents is not readily available. There is still no consensus on the safe use of topical retinoids in pregnancy, and the occurrence of pseudomembranous colitis after the topical use of clindamycin does not appear to be of clinical relevance. In general, topical anti-acne agents are well tolerated and, as would be expected from their limited transdermal uptake, other significant safety concerns have not so far arisen.

Immunology of diseases associated with Malassezia species

Malassezia species are members of the human cutaneous commensal flora, in addition to causing a wide range of cutaneous and systemic diseases in suitably predisposed individuals. Studies examining cellular and humoral immune responses specific to Malassezia species in patients with Malassezia-associated diseases and healthy controls have generally been unable to define significant differences in their immune response. The use of varied antigenic preparations and strains from different Malassezia classifications may partly be responsible for this, although these problems can now be overcome by using techniques based on recent work defining some important antigens and also a new taxonomy for the genus. The finding that the genus Malassezia is immunomodulatory is important in understanding its ability to cause disease. Stimulation of the reticuloendothelial system and activation of the complement cascade contrasts with its ability to suppress cytokine release and downregulate phagocytic uptake and killing. The lipid-rich layer around the yeast appears to be pivotal in this alteration of phenotype. Defining the nonspecific immune response to Malassezia species and the way in which the organisms modulate it may well be the key to understanding how Malassezia species can exist as both commensals and pathogens.

Combination azelaic acid therapy for acne vulgaris

There is no topical antiacne medication that acts against all four of the major pathophysiologic features of acne: hyperkeratinization, sebum production, bacterial proliferation, and inflammation. Topical azelaic acid cream helps both to normalize keratinization and to reduce the proliferation of Propionibacterium acnes, and has proven to be effective against both noninflammatory and inflammatory lesions. The results of a recent study now demonstrate that its efficacy can be enhanced, and patient ratings of overall impression improved, when it is used in combination with other topical medications such as benzoyl peroxide 4% gel, clindamycin 1% gel, tretinoin 0.025% cream, and erythromycin 3%/benzoyl peroxide 5% gel. Furthermore, another study has shown that azelaic acid plus benzoyl peroxide achieves greater efficacy and higher patient ratings of convenience than monotherapy with erythromycin-benzoyl peroxide gel.

A comparison of topical azelaic acid 20% cream and topical metronidazole 0.75% cream in the treatment of patients with papulopustular rosacea

BACKGROUND

Although it is important for physicians to have sufficient clinical data on which to base treatment decisions, little comparative data exist regarding newer treatment modalities for rosacea.

OBJECTIVE

The goal of the study was to compare the efficacy and safety of topical azelaic acid 20% cream and topical metronidazole 0.75% cream in the treatment of patients with papulopustular rosacea. Parameters of patient satisfaction to treatment were also assessed.

METHODS

Forty patients with the clinical manifestation of symmetric facial rosacea were investigated in this single-center, double-blind, randomized, contralateral split-face comparison clinical trial.

RESULTS

After 15 weeks of treatment, both azelaic acid and metronidazole induced significant, albeit equal reductions in the number of inflammatory lesions (pustules and papules). A significantly higher physician rating of global improvement was achieved with azelaic acid. Changes in the rosacea signs and symptoms of dryness, burning, telangiectasia, and itching were equal between treatments. A reduction in erythema tended toward significance with azelaic acid at week 15. A trace amount of stinging on application was noted with azelaic acid; however, such discomfort did not appear to concern patients because their overall impression of azelaic acid was superior to that of metronidazole.

CONCLUSION

Azelaic acid 20% cream provides an effective and safe alternative to metronidazole 0.75% cream with the added benefit of increased patient satisfaction.

Azelaic acid 20% cream in the treatment of facial hyperpigmentation in darker-skinned patients

This multicenter, randomized, double-masked, parallel-group study assessed the efficacy, safety, and tolerability of azelaic acid 20% cream compared with those of its vehicle for the treatment of facial hyperpigmentation in darker-skinned patients (phototypes IV to VI). Following a 24-week treatment period, azelaic acid produced significantly greater decreases in pigmentary intensity than did vehicle as measured by both an investigator's subjective scale (P = 0.021) and a chromometer analysis (P = 0.039). There was a significantly greater global improvement with azelaic acid than with vehicle at week 24 (P = 0.008). Azelaic acid produced a slightly but significantly greater amount of burning (weeks 4 and 12, P < or = 0.046) and stinging (week 4, P = 0.002) than did vehicle. At the end of the study, more patients treated with azelaic acid than with vehicle reported having much smoother skin and being very satisfied or satisfied with their treatment. Also, more patients treated with azelaic acid than with vehicle rated their medication as being more effective or the same as past treatments. Thus azelaic acid is an effective and well-tolerated treatment for hyperpigmentation in darker-skinned patients.

Effect of keigai-rengyo-to, a Japanese kampo medicine, on neutrophil functions: a possible mechanism of action of keigai-rengyo-to in acne

On the basis of recent reports that keigai-rengyo-to (TJ-50), an oral Japanese Kampo (herb) medicine, is clinically effective in treating acne, and that tetracyclines are effective against acne by acting directly as an antioxidant on infiltrated neutrophils, we investigated the effect of TJ-50 on the generation of reactive oxygen species (ROS), using human neutrophils and a cell-free, xanthine-xanthine oxidase system. The species investigated were superoxide radical anion (O2-), hydrogen peroxide (H2O2), and hydroxyl radical (OH.). In addition, neutrophil chemotaxis, phagocytosis and calcium concentration, [Ca2+]i in neutrophils were also assessed. TJ-50 significantly decreased neutrophil-generated O2-, H2O2 and OH. in a dose-dependent manner. Three kinds of ROS generated in the cell-free system were also reduced in the presence of TJ-50. On the other hand, the medicine did not markedly affect neutrophil chemotaxis, phagocytosis or [Ca2+]i in neutrophils. Our results indicate that the clinical effectiveness of TJ-50 in the treatment of acne may be due partly to its antioxidant action on infiltrated neutrophils.

Effect of nadifloxacin on neutrophil functions

Recent reports indicate that nadifloxacin is an effective therapy for acne vulgaris and has a mechanism of action similar to that of the tetracyclines which act directly as antioxidants against infiltrated neutrophils. The effects of nadifloxacin on neutrophil functions, including the generation of reactive oxygen species, chemotaxis and phagocytosis were investigated. Nadifloxacin reduced the numbers of superoxide radical anions (O2-) and hydroxyl radicals (OH.) generated by neutrophils. The drug did not, however, significantly inhibit neutrophil chemotaxis and phagocytosis nor did it decrease the levels generated in a cell-free, xanthine-xanthine oxidase system. These results indicate that the clinical effectiveness of nadifloxacin may be partly due to its inhibitory action on the generation of O2- and OH. by neutrophils leading to a reduction in oxidative tissue injury.

Azelaic acid. A review of its pharmacological properties and therapeutic efficacy in acne and hyperpigmentary skin disorders

Azelaic acid is a naturally occurring saturated dicarboxylic acid which, on topical application (usually as a 20% cream), has been shown to be effective in the treatment of comedonal acne and inflammatory (papulopustular, nodular and nodulocystic) acne, as well as various cutaneous hyperpigmentary disorders characterised by hyperactive/abnormal melanocyte function, including melasma and, possibly, lentigo maligna. In addition, azelaic acid has an antiproliferative and cytotoxic effect on the human malignant melanocyte, and preliminary findings indicate that it may arrest the progression of cutaneous malignant melanoma. The mechanism of this selective cytotoxic action of azelaic acid is unclear, but may possibly be related to its inhibition of mitochondrial oxidoreductase activity and DNA synthesis. In controlled studies, topical azelaic acid demonstrated comparable anti-acne efficacy to topical tretinoin, benzoyl peroxide, erythromycin and oral tetracycline, while in patients with melasma azelaic acid proved at least as effective as topical hydroquinone. On topical application azelaic acid is well tolerated, with adverse effects apparently limited to a generally mild and transient local cutaneous irritation. Thus, topical azelaic acid, employed either as monotherapy or in combination with other treatments, is likely to prove of value in the management of acne and several hyperpigmentary disorders, most notably melasma.