Antioxidants and narrow band-UVB in the treatment of vitiligo: a double-blind placebo controlled trial

BACKGROUND

Vitiligo is an acquired depigmenting disease with uncertain aetiopathogenesis, possibly associated with oxidative stress. Narrowband ultraviolet B phototherapy (NB-UVB) is the most widely used and effective treatment.

AIM

To evaluate the clinical effectiveness of NB-UVB and the repairing of oxidative stress-induced damage, using oral supplementation with an antioxidant pool (AP).

METHODS

Patients (n = 35) with nonsegmental vitiligo were enrolled in a randomized, double-blind, placebo-controlled multicentre trial. The treatment group received, for 2 months before and for 6 months during the NB-UVB treatment, a balanced AP containing alpha-lipoic acid, vitamins C and E, and polyunsaturated fatty acids. The area and number of lesions, as well as some parameters of the oxidation-reduction (redox) status of the peripheral blood mononuclear cells (PBMCs) were estimated at the beginning, after 2 months, and at the end of the trial.

RESULTS

In total, 28 patients completed the study. After 2 months of AP supplementation, the catalase activity and the production of reactive oxygen species (ROS) were 121% and 57% of the basal values (P < 0.05 and P < 0.02 vs. placebo, respectively). The AP increased the therapeutic success of NB-UVB, with 47% of the patients obtaining > 75% repigmentation vs. 18% in the placebo group (P < 0.05). An increase in catalase activity to 114% (P < 0.05 vs. placebo) and decrease in ROS level of up to 60% (P < 0.02 vs. placebo) of the basal value was observed in PBMCs. Finally, the AP intake maintained the membrane lipid ratio (saturated : unsaturated fatty acids 1.8 : 3.1; P < 0.05), counteracting phototherapy-induced saturation.

CONCLUSIONS

Oral supplementation with AP containing alpha-lipoic acid before and during NB-UVB significantly improves the clinical effectiveness of NB-UVB, reducing vitiligo-associated oxidative stress.

Vitiligo pathogenesis: autoimmune disease, genetic defect, excessive reactive oxygen species, calcium imbalance, or what else?

The pathobiology of vitiligo has been hotly disputed for as long as one remembers, and has been a magnet for endless speculation. Evidently, the different schools of thought--ranging, e.g. from the concept that vitiligo essentially is a free-radical disorder to that of vitiligo being a primary autoimmune disease--imply very different consequences for the best therapeutic strategies that one should adopt. As a more effective therapy for this common, often disfiguring pigmentary disorder is direly needed, we must strive harder to settle the pathogenesis debate definitively--on the basis of sound experimental evidence, rather than by a war of dogmatic theories. Recognizing, however, that it is theories which tend to guide our experimental designs and choice of study parameters, the various pathogenesis theories on the market deserve to be critically, yet unemotionally re-evaluated. This Controversies feature invites you to do so, and to ask yourself: is there something important or worthwhile exploring in other pathogenesis scenarios than those already favoured by you that may help you improve your own study design, next time you have a fresh look at vitiligo? Vitiligo provides a superb model for the study of many fundamental problems in skin biology and pathology. Therefore, even if it later turns out that, as far as your own vitiligo pathogenesis concept is concerned, you have barked-up the wrong tree most of the time, chances are that you shall anyway have generated priceless new insights into skin function along the way.

Ultrastructural findings in progressive macular hypomelanosis indicate decreased melanin production

BACKGROUND

The pathogenesis of progressive macular hypomelanosis (PMH) is unknown. Recently, Westerhof et al. (Arch Dermatol 2004; 140: 210-214) hypothesized that Propionibacterium acnes produces a depigmenting factor that interferes with melanogenesis in the skin, resulting in hypopigmented spots. The purpose of the study is to gain an insight into the pathogenesis of PMH.

MATERIALS AND METHODS

We took a biopsy of 2-mm diameter from normal and lesional skin in eight PMH patients. Using electron microscopy, we compared melanization of melanosomes, melanosome transfer and amount of epidermal melanin in normal and lesional skin.

RESULT

Compared to non-lesional skin, we observed a decrease of epidermal melanin and less melanized melanosomes in lesional skin of all patients. When comparing normal and lesional skin of patients with skin type V and VI, we observed a difference in melanosome size and maturation and a switch of transferred melanosomes from single stage IV transferred melanosomes to aggregated stage I, II and III transferred melanosomes, as seen in healthy skin of skin type I to IV.

CONCLUSION

Hypopigmentation in PMH seems to be the result of an altered melanogenesis based on a decrease in melanin formation and a change in the distribution of melanosomes. In lesional skin of PMH patients with skin type V and VI less melanized, aggregated melanosomes in stead of single, mature melanosomes are transferred from melanocytes to keratinocytes. This results in a decrease of epidermal melanin. Further investigations are needed to determine the precise role of Propionibacterium acnes in this alteration of melanogenesis.

Treatment of vitiligo vulgaris with narrow-band UVB and oral Polypodium leucotomos extract: a randomized double-blind placebo-controlled study

BACKGROUND

The first choice treatment for vitiligo vulgaris is narrow-band UVB (NB-UVB), but no satisfactory treatment exists.

OBJECTIVES

To investigate if Polypodium leucotomos, an antioxidative and immunomodulatory plant extract, improves NB-UVB-induced repigmentation.

METHODS

Fifty patients with vitiligo vulgaris randomly received 250 mg oral P. leucotomos or placebo three times daily, combined with NB-UVB twice weekly for 25-26 weeks.

RESULTS

Repigmentation was higher in the P. leucotomos group vs. placebo in the head and neck area (44% vs. 27%, P = 0.06). Small repigmentation increases (P = n.s.) were observed for the trunk (6% increased repigmentation), extremities (4%), and hands and feet (5%) in the P. leucotomos group vs. placebo. Patients attending more than 80% of required NB-UVB sessions showed increased repigmentation in the head and neck area in the P. leucotomos group vs. placebo (50% vs. 19%, P < 0.002); no significant differences were seen in the other body areas. Patients with skin types 2 and 3 showed more repigmentation in the head and neck area in the P. leucotomos group vs. placebo (47% vs. 21%, P = 0.01), and no significant differences were seen in the other body areas. No conclusions could be drawn on skin types 4 and 5 due to low patient numbers.

CONCLUSION

There is a clear trend towards an increase in repigmentation of vitiligo vulgaris affecting the head and neck area when NB-UVB phototherapy is combined with oral P. leucotomos. This effect may be more pronounced in light skin types.

Evaluation of the effects of NB-UVB in both segmental and non-segmental vitiligo affecting different body sites

BACKGROUND

Narrow band (NB)-UVB has been used in the treatment of vitiligo for years but statistical evaluation of the clinical response in both segmental and non-segmental vitiligo patients has yet to be assessed.

OBJECTIVES

Statistical evaluation of the clinical response of vitiligo patients to NB-UVB in both segmental and non-segmental types affecting different body sites.

METHODS

This study included 150 patients with vitiligo either segmental (10%) or non-segmental (90%). NB-UVB therapy was given twice weekly till reaching our end point of 100% re-pigmentation or a cut point in unresponsive cases. Evaluation of the percentage of re-pigmentation was performed by total body photography and planimetry every 8 weeks.

RESULTS

The overall response to therapy in the non-segmental vitiligo group demonstrated that 48% of the patients showed marked response, 27% showed moderate response and 25% showed mild response after UVB therapy. The patients showed marked response in 76.3% in face lesions, 41.9% in trunk lesions and 37.6% in limbs lesions. None of the patients in the acral areas achieved marked response. The mean duration of therapy was 7.8 months. Moreover, the results demonstrated that the earlier the patient was treated, the better the response was especially for lesions on the face, trunk and limbs. On the other hand, in the segmental vitiligo group, patients showed no more than mild response to NB-UVB whatever the site of the lesion was. No side effects were encountered with NB-UVB therapy except for aggravation of the disease in two cases and erythema in one patient who was an outdoor worker and was skin type II.

CONCLUSION

The type of vitiligo, the affected anatomical area and the disease duration are important factors that influence potential re-pigmentation.

Hydroquinone and its analogues in dermatology - a potential health risk

Hydroquinone has been used for decades as a skin lightening agent. Since January 1, 2001, its use in cosmetics has been banned. This ban is as a result of mid-term effects such as leukoderma-en-confetti/occupational vitiligo and exogenous ochronosis. However, a recent literature search on hydroquinone as a skin lightening agent suggests that possible long-term effects such as carcinogenesis may be expected as well. Metabolites of hydroquinone formed in the liver, e.g., p-benzoquinone and glutathione conjugates of hydroquinone, are mainly responsible for this. In the bone marrow, hydroquinone is oxidized into p-benzoquinone because of the high myeloperoxidase activity. Topically applied hydroquinone-containing creams may give rise to accumulation of these compounds, which can cause DNA damage and mutations. They also have the capability to disrupt protective mechanisms, whereby they facilitate further development of cancer. In the bone marrow, long-term effects such as aplastic anemia and acute myeloid leukemias may occur. Most of the evidence stems from research on benzene toxicity, which appears to arise via its metabolite hydroquinone. There is no report yet demonstrating carcinogenesis resulting from the application of hydroquinone-containing creams. However doctors should be aware of these potential health risks which were up until now disregarded.

Hypermelanocytic guttate and macular segmental hypomelanosis

We report two sisters, 27 and 30 years of age, with a cutaneous pigmentary anomaly, which seems to be a new entity. At the age of 26 years the elder sister developed an asymptomatic and persistent rash consisting of discrete, grouped, round to oval, guttate and nummular, hypopigmented macules, 0.2-5 cm in diameter. The distribution of the lesions was unilateral. They were located on the right side of the thorax with a moderately sharp demarcation in the mid-line and ran in a segmental distribution over the right arm, hand and fingers. Microscopic examination of lesional skin scrapings was negative for fungi. Examination with Wood's light accentuated the lesions from the surrounding normal skin. The younger sister had experienced identical, mostly guttate, skin lesions for many years, which at examination were distributed on all extremities and buttocks, and to a lesser degree on the trunk, but here in a segmental distribution. Histological examination (Masson-Fontana staining) of lesional skin of both sisters was identical. A slightly thinned epidermis and a marked decrease in pigmentation of the epidermal basal layer was seen. Electron microscopic examination of lesional skin showed an overall linear increase of morphologically and cytologically normal melanocytes just above the epidermal basal membrane. At many places the density of melanocytes was so high that the keratinocytes were displaced from the basal layer. The melanocytic dendrites extended into the suprabasal layer. The keratinocytes of lesional skin showed a decreased number of melanosomes. It is paradoxical that a hypomelanotic macule shows a histological picture of an increase in normal functioning melanocytes. In all probability a deficient melanosome transfer is responsible for this unexpected phenomenon.

[Toxicological aspects and health risks associated with hydroquinone in skin bleaching formula]

The use of hydroquinone as a cosmetic skin-bleaching agent has been forbidden since January 2001. It is now available only on prescription. The ban has been introduced because of medium-term effects such as white patches on the skin, particularly on the face (leukoderma with confetti-like depigmentation), and subcutaneous dark collections of pigment (exogenous ochonosis). Long-term effects are a possibility; cancer being the most likely. Renal adenomas and leukaemia occurred in animal experiments indicating the nephrotoxicity and carcinogenic properties of the substance. It is now known how hydroquinone and its metabolites can cause damage to DNA and inhibit apoptosis of mutated cells. The carcinogenic action of benzene is difficult to attribute to its hydroquinone metabolite. Daily use of hydroquinone causes it to accumulate in the body as absorption into the skin is faster than excretion in the urine. The use of hydroquinone as a skin-bleaching agent is accordingly unsafe and should be completely banned. Alternatives such as azaleic acid and thioctic acid (alpha-lipoic acid) are available.

Treatment of acquired junctional melanocytic naevi by Q-switched and normal mode ruby laser

BACKGROUND

Acquired junctional melanocytic naevi are harmless pigmented lesions of the epidermis, which can be of cosmetic concern. Various therapeutic approaches have been used in the treatment, but all these methods produce postoperative scarring or alterations in skin texture. Pigment laser treatment of benign pigmented lesions has shown a low potential for scarring by selectively targeting melanosomes in melanocytes and keratinocytes.

OBJECTIVE

To find a fast, effective and safe treatment for the removal of acquired junctional melanocytic naevi.

PATIENTS/METHODS

We first studied the effect of the Q-switched and normal mode ruby laser on 12 patients (eight women and four men) with acquired melanocytic naevi. The effect was monitored by histology and clinical photography.

RESULTS

If the response to one treatment with the Q-switched laser mode was not completely effective, the lesions were subsequently treated with one or two sessions with the laser in normal mode. All flat lesions responded completely. After a follow-up period of 1 year they had not recurred. Slightly elevated lesions showed only a partial response, e.g. disappearance of the junctional part of the naevus but recurrence of the dermal part of the naevus. Red-brown junctional naevi as seen in skin types I and II did not respond well to ruby laser treatment.

CONCLUSIONS

The Q-switched ruby laser was very successful in completely removing flat (non-palpable) acquired junctional melanocytic naevi, but not compound naevi, with one to three treatment sessions, without any scarring or pigmentary disturbance.

Vitiligo. Pathogenesis and treatment

Vitiligo is an acquired skin disorder caused by the disappearance of pigment cells from the epidermis that gives rise to well defined white patches which are often symmetrically distributed. The lack of melanin pigment makes the lesional skin more sensitive to sunburn. Vitiligo can be cosmetically disfiguring and it is a stigmatizing condition, leading to serious psychologic problems in daily life. It occurs worldwide in about 0.5% of the population and it occurs as frequently in males as it does in females. The cause is unknown, but might involve genetic factors, autoimmunity, neurologic factors, toxic metabolites, and lack of melanocyte growth factors. Since a causative (gene) treatment is not (yet) available, current modalities are directed towards stopping progression and to achieving repigmentation in order to repair the morphology and functional deficiencies of the depigmented skin areas. Many treatments have been used for some time; however; there are some new developments: narrowband ultraviolet (UV) B (311 nm) therapy, the combination of corticosteroid cream + UVA therapy, and the transplantation of autologous pigment cells in various modalities. In widespread vitiligo, residual pigment can be removed by depigmentation agents. Sunscreens, camouflage products, and good guidance may help the patient cope better with the disease.

Aberrant expression of complement regulatory proteins, membrane cofactor protein and decay accelerating factor, in the involved epidermis of patients with vitiligo

BACKGROUND

Vitiligo is a pigmentary disorder of the skin characterized by the complete absence of melanocytes from the lesion. Complement-activating antimelanocyte antibodies have been implicated in vitiligo pathogenesis. As membrane regulators of complement activation, membrane cofactor protein, decay accelerating factor and CD59 protect cells from elimination by autologous complement, their absence or downregulation on melanocytes may be associated with autoantibody and complement-mediated melanocyte destruction in vitiligo.

OBJECTIVES

We studied the expression of these regulatory proteins in non-lesional, perilesional and lesional vitiligo skin compared with those of control specimens.

METHODS

We used immunohistochemistry to study the expression of the regulatory proteins, and flow cytometric analysis of cultured melanocytes to investigate possible constitutive changes in the expression levels of these molecules. We also investigated whether melanocytes can influence keratinocyte susceptibility to autologous complement by regulating keratinocytic decay accelerating factor and membrane cofactor protein expression levels.

RESULTS

Immunohistochemical data showed that expression of membrane cofactor protein and decay accelerating factor in whole epidermis was lower in lesional and perilesional skin in comparison with non-lesional skin. The reduced in situ expression appeared to be specific to vitiligo. However, coculture experiments indicated that melanocytes do not influence keratinocyte susceptibility to autologous complement. Further, flow cytometric analysis of cultured melanocytes convincingly demonstrated that non-lesional vitiligo and control melanocytes have comparable decay accelerating factor, membrane cofactor protein and CD59 expression levels.

CONCLUSIONS

It is therefore concluded that there is no constitutive melanocyte defect per se that could be related to the in vivo expression of these molecules in vitiligo. Nevertheless, the present data suggest that both keratinocytes and melanocytes in the involved vitiliginous whole epidermis express lower levels of decay accelerating factor and membrane cofactor protein compared with controls that could render them more vulnerable to autologous complement attack.

Linkage and association of HLA class II genes with vitiligo in a Dutch population

BACKGROUND

Serological typing of HLA has shown discrepancies in HLA associations with vitiligo in different ethnic populations.

OBJECTIVES

To perform genotyping of HLA class II genes on a Dutch vitiligo population in order clearly to identify susceptible and protective HLA alleles in vitiligo.

METHODS

HLA typing was carried out by amplifying genomic DNA by polymerase chain reaction (PCR) followed by dot-blot hybridization with sequence-specific oligonucleotides (SSO). Fifty Dutch vitiligo probands, and their parents (150 individuals) and 204 healthy controls were studied.

RESULTS

Family-based case-control association studies and linkage disequilibrium analysis showed the linkage and association of DRB4*0101 allele with vitiligo (P(c) = 0.0016, relative risk = 2.21). The family-based association study also provided evidence for linkage and association of DQB1*0303 allele with vitiligo (chi(2) = 7.36, P = 0.006). We measured the clinical relevance of the test by calculating the prevalence corrected positive predictive values (PcPPV). The PcPPV of disease for the DRB4*0101 allele was 0.017 and for the DRB4*0101/0101 genotype was 0.0358. In other words, a DRB4*0101/0101 genotype carries a 3.58% risk of developing vitiligo.

CONCLUSIONS

Both DRB4*0101 and DQB1*0303 alleles provide significant susceptibility for vitiligo.

Mucopolysaccharides from psyllium involved in wound healing

Mucopolysaccharides derived from the husk of psyllium (Plantago ovata) have properties beneficial for wound cleansing and wound healing. Recent studies indicate that these mucopolysaccharides also limit scar formation. Our in vitro and in vivo studies aimed to investigate the mechanisms involved, e.g., fluid absorption, bacterial adherence and in vitro stimulatory effects on macrophages, which are pivotal in wound healing. The mucopolysaccharides contained in a sachet (Askina Cavity) or in a hydrocolloid mixture (Askina Hydro) were found to have a gradual and sustained absorbency over a period of 7 days, amounting to 4-6 times their weight in water. The swelling index was 9 mm after 312 h. Adherence of wound bacteria to the mucopolysaccharides started after 2 h and was more pronounced after 3 h. Semiquantitative measurements of bacterial adherence used centrifugation and subsequent optical density determinations of supernatant. These confirmed the strong adherence potential of psyllium particles. Lactic acid dehydrogenase staining of pretreated cultured human skin explants did not reveal toxicity of the mucopolysaccharides derived from psyllium husk. Langerhans' cell migration from the epidermis was negligible and interleukin-1 beta expression in the explants was not significant, supporting the very low allergenic potential of psyllium. The characteristics of mucopolysaccharide granulate derived from psyllium husk in Askina Cavity and Askina Hydro related to fluid absorption, bacterial adherence, biocompatibility, stimulation of macrophages, irritancy response and allergenicity showed an optimal profile, supporting the good clinical performance of wound healing products containing psyllium husk.

Expression and modulation of apoptosis regulatory molecules in human melanocytes: significance in vitiligo

Although the aetiology of the hypopigmentary disorder vitiligo is ill understood, it is clear that pigment producing cells are absent from vitiliginous lesional skin. The present study was designed to investigate the possible role of melanocyte-expressed apoptosis regulatory molecules in melanocyte disappearance. Flow cytometric evaluation of p53, p21, Bcl-2 and Bax revealed no differences in in vitro expression levels between normal control and non-lesional melanocytes. Moreover, no in situ immunohistological differences were observed in melanocytes present in control, non-lesional and perilesional skin. However, an enhanced number of p53+ nuclei, in the absence of detectable p21 expression, was detected in involved areas. The observed p53 expression pattern did not involve melanocytes and could be the result of ultraviolet (UV) A irradiation. Further, we showed that UVB is capable of modulating melanocyte-expressed apoptosis regulatory molecules. Consequently, a lethal dose of UVB was given to two groups of cultured normal control and non-lesional melanocytes. No significant differences were found when comparing the percentages and kinetics of UVB-induced apoptosis in these groups. In conclusion, our results indicate that the relative apoptosis susceptibility of melanocytes in vitiligo is comparable with that of normal control cells. It is therefore unlikely that vitiligo is causally related to dysregulation of apoptosis regulatory molecules.

Local immune response in skin of generalized vitiligo patients. Destruction of melanocytes is associated with the prominent presence of CLA+ T cells at the perilesional site

In situ immune infiltrates in lesional, perilesional, and nonlesional skin biopsies from patients with vitiligo were analyzed by immunohistochemistry and compared with immune infiltrates found in the skin of normal healthy donors and relevant disease controls. An increased influx of activated skin-homing T cells and macrophages were seen in the perilesional biopsies. The overall percentages of cutaneous leukocyte-associated antigen-positive (CLA+) T cells were similar to those found in normal healthy donors. This is compatible with the similar expression of E-selectin. Most strikingly, however, the CLA+ T cells in perilesional skin were mainly clustered in the vicinity of disappearing melanocytes, and 60% to 66% of these interacting T cells expressed perforin and granzyme-B. The perforin+/granzyme-B+ cells were not seen in locations different from that of disappearing melanocytes. Interestingly, the majority of the infiltrating T cells were HLA-DR/CD8+. Another hallmark of the present study is the focal expression of intercellular adhesion molecule (ICAM)-1 and HLA-DR in the epidermis at the site of interaction between the immune infiltrates and the disappearing melanocytes. The data presented in this study are consistent with a major role for skin-homing T cells in the death of melanocytes seen in vitiligo.

Depigmentation therapy in vitiligo universalis with topical 4-methoxyphenol and the Q-switched ruby laser

BACKGROUND

Monobenzylether of hydroquinone is used worldwide to remove residual pigment in patients with vitiligo universalis. Because of the side effects reported with this drug, the use of monobenzylether of hydroquinone has been restricted in The Netherlands.

OBJECTIVE

Our purpose was to evaluate the long-term effectiveness and safety of a combination therapy consisting of topical 4-methoxyphenol (4-MP) cream and Q-switched ruby (QSR) laser in 16 patients with vitiligo universalis.

METHODS

In a retrospective study, patient record forms were evaluated. Data were collected regarding history as well as physical and histologic examination. The patients came to the institute for a follow-up visit after a treatment-free period of 2 to 36 months.

RESULTS

Thirteen patients received both therapies. Three patients only used the cream. None of the areas was treated by the cream and QSR laser at the same time. In 11 of the 16 patients (69%; 95% confidence interval [CI], 41%-89%) total depigmentation was achieved using the 4-MP cream. Onset of depigmentation was between 4 and 12 months. Four of the 5 patients who did not respond to the 4-MP cream had successful depigmentation with the QSR laser. Mild burning or itching was reported with the cream in 4 cases (25%). Of the 11 patients who responded to the 4-MP cream, 4 had recurrence of pigmentation (relapse rate of 36%; 95% CI, 11%-69%) after a treatment-free period of 2 to 36 months. In 9 of the 13 patients (69%; 95% CI, 39%-91%) total depigmentation was achieved after QSR laser therapy. Onset of depigmentation was between 7 and 14 days after the treatment. Three of the 4 unresponsive patients showed total depigmentation after application of the 4-MP cream. No side effects were observed. Of the 9 patients who responded to QSR laser therapy, 4 had recurrence of pigmentation (relapse rate of 44%; 95% CI, 14%-79%) after a treatment-free period of 2 to 18 months. These patients had a negative Koebner phenomenon.

CONCLUSION

Depigmentation therapy using a 4-MP cream and/or QSR laser therapy is an effective and safe method to remove disfiguring residual pigment in patients with vitiligo universalis. Patients should be warned that repigmentation may occur, even after total depigmentation has been achieved.

PIG3V, an immortalized human vitiligo melanocyte cell line, expresses dilated endoplasmic reticulum

Vitiligo is an enigmatic pigmentary disorder of the skin. Factors potentially involved in the progressive loss of melanocytes from the basal layer of the epidermis include genetically determined aberrancies of the vitiligo melanocyte. It follows that analysis of melanocytes cultured from vitiligo donors can contribute to a further understanding of the etiopathomechanism. A setback for vitiligo research has been the limited availability of vitiligo-derived melanocytes. To overcome this limitation, we have generated a vitiligo melanocyte cell line according to a protocol established previously for the immortalization of normal human melanocytes. Vitiligo melanocytes Ma9308P4 were transfected with HPV16 E6 and E7 genes using the retroviral construct LXSN16E6E7. Successful transformants were selected using geneticin and subsequently cloned to ensure genetic homogeneity. The resulting cell line PIG3V has undergone more than 100 cell population doublings since its establishment as a confluent primary culture, whereas untransfected melanocytes derived from adult skin senesce after a maximum of 50 population doublings. Cells immortalized by this transfection procedure retain lineage-specific characteristics and proliferate significantly faster than parental cells. In this study, the phenotype of PIG3V resembled melanocytes rather than melanoma cells in culture. Tyrosinase was processed properly and melanosomes remained pigmented. Importantly, ultrastructural characterization of PIG3V cells revealed dilated endoplasmic reticulum profiles characteristic of vitiligo melanocytes. An explanation for this dilation may be found in the retention of proteins with molecular weight of 37.5. 47.5, and 56.5 kDa, as determined by gel electrophoresis of microsomal proteins isolated from radiolabeled cells.

Treatment of generalized vitiligo in children with narrow-band (TL-01) UVB radiation therapy

BACKGROUND

Only a few clinical trials have been performed on the treatment of generalized vitiligo in children. Recently, narrow-band UVB therapy has been reported to be an effective and safe therapeutic option in adult patients with vitiligo.

OBJECTIVE

We studied the efficacy and safety of UVB (311 nm) therapy in children with generalized vitiligo and evaluated the effect of the therapy on the quality of life in these children.

METHODS

In an open trial, 51 children (20 males, 31 females) with generalized vitiligo were treated twice weekly with narrow-band UVB radiation therapy for the maximum period of 1 year. The Children's Dermatology Life Quality Index (CDLQI) was used to evaluate the psychosocial impact of disease and treatment and was scored before and after therapy.

RESULTS

The treatment resulted in more than 75% overall repigmentation in 53% of patients and in stabilization of the disease in 80%. Responsiveness to therapy was positively correlated with localization of the lesions and the patients' compliance. Adverse events were limited and transient. The better the repigmentation grade, the better the CDLQI scores had improved.

CONCLUSION

Narrow-band UVB therapy is effective and safe in childhood vitiligo; it also may significantly improve the quality of life.

Vitiligo management update

Vitiligo is an acquired skin disorder caused by the disappearance of pigment cells from the epidermis, and results in well defined white patches that are often symmetrically distributed. The lack of melanin pigment makes the lesional skin more sensitive to sunburn. Vitiligo can be cosmetically disfiguring and is a stigmatizing condition, leading to serious psychological problems in daily life. It occurs worldwide in about 1% of the population, mostly between the ages of 10-30 years, and as often in males as in females. The cause is unknown, but might involve genetic factors, autoimmunity, toxic metabolites, and/or a higher vulnerability of melanocytes. Some new treatments for this condition include corticosteroid + UVA treatment, UVB narrow wave band (311 nm) irradiation, and transplantation of autologous pigment cells. In widespread vitiligo, residual pigment can be removed by depigmentation agents. Sunscreens, camouflage products and good guidance may help the patient to better cope with this disease.

The development of guidelines for the treatment of vitiligo. Clinical Epidemiology Unit of the Istituto Dermopatico dell'Immacolata-Istituto di Recovero e Cura a Carattere Scientifico (IDI-IRCCS) and the Archives of Dermatology

OBJECTIVE

To develop and introduce evidence-based guidelines for the treatment of vitiligo in children and in adults.

PATIENTS AND SETTING

Patients, residents, and dermatologists from the Department of Dermatology, Academic Medical Center, University of Amsterdam, and the Netherlands Institute for Pigmentary Disorders in Amsterdam.

DESIGN

Scientific evidence obtained from 3 systematic reviews of the literature was combined with the results of 2 questionnaires and interviews of potential users of the guidelines, 3 internal expert meetings, and 1 local expert meeting, during which preliminary guidelines were presented and commented on. A final version of the guidelines was synthesized and disseminated among potential users. Six months after the introduction of these guidelines, their use was evaluated.

RESULTS

Before the development of the guidelines, there was no uniformity in treatment selection, and there was a variability in estimates of treatment outcome. The metaanalysis showed class 3 corticosteroids and narrowband UV-B to be the most effective and safest therapies for localized and for generalized vitiligo, respectively. From another systematic review, it could be concluded that patients with segmental, stable, or lip-tip vitiligo could be successfully treated with most autologous transplantation methods. For vitiligo universalis, results of the systematic review showed that depigmentation using monobenzone or a Q-switched ruby laser was equally effective. The final version of the guidelines consisted of a treatment scheme together with detailed treatment protocols. Implementation of the guidelines was evaluated in 5 physicians. After the introduction of these guidelines, they were followed in most adult cases with vitiligo (71% of patients with localized vitiligo, 82% with generalized vitiligo, 100% with stable or segmental vitiligo, and 80% with universal vitiligo). In children with vitiligo, the physicians adhered to the guidelines for 52% of the cases.

CONCLUSIONS

Guidelines for the treatment of vitiligo can be successfully developed and disseminated for daily clinical practice. The results of the implementation of these guidelines should be confirmed in other centers involving more clinicians.

Management of vitiligo. Results of a questionnaire among dermatologists in The Netherlands

BACKGROUND

Several therapeutic options are available for the treatment of vitiligo. Concern exists that there is no uniform approach towards the management of vitiligo among Dutch dermatologists.

METHODS

A written survey concerning the management of vitiligo was sent to 332 dermatologists in The Netherlands.

RESULTS

The response rate was 86%. "Giving information and reassurance concerning the nature of disease" was regarded by most dermatologists (68%) as being the most important goal in the management of vitiligo. Only 16% of the dermatologists aimed for active treatment in vitiligo. The reported therapy choices in children resembled those of adults, except that slightly more dermatologists did not prescribe active therapy in children. Nine different therapeutic modalities were mentioned as first choice therapies. Topical corticosteroids were indicated by most dermatologists as first choice therapy (241 out of 266, i.e. 91%); however, only 2% indicated that 50% or more of the patients achieved a successful treatment; 66% found that less than 25% of the patients were successfully treated with topical corticosteroids. Only 15% of the respondents reported that 50% or more of the patients were treated successfully with narrow-band UVB. The observed response profile to broad-band UVB therapy was found to be comparable with that of narrow-band UVB. The classical therapy with oral psoralen plus UVA (PUVA) was prescribed as first choice therapy by only 12% (32 out of 266) of the dermatologists. Only 6% of these respondents observed that 50% or more of the patients achieved successful therapy using oral PUVA. The recommended maximum treatment duration for topical corticosteroids, oral PUVA, and UVB therapy was found to vary from 3 to 12 months.

CONCLUSIONS

Most dermatologists in The Netherlands do not offer active treatment in vitiligo, probably because the estimated effectiveness of (nonsurgical) repigmentation therapy is low. In cases where treatment is prescribed, there appears to be no consensus on the choice of therapies and treatment strategies. The development of practice guidelines may be helpful in reducing inappropriate care and improving treatment outcome.

Left-right comparison study of the combination of fluticasone propionate and UV-A vs. either fluticasone propionate or UV-A alone for the long-term treatment of vitiligo

OBJECTIVE

To compare the efficacy and safety of using a combination of fluticasone propionate (FP) and UV-A with that of either drug used alone in the long-term treatment of vitiligo.

DESIGN

Prospective, randomized, controlled, left-right comparison study. Repigmentation was judged by a single dermatologist (L.N.-K.) and skin thickness was scored by a pathologist (using biopsy samples), a dermatologist (L.N.-K.) (visually), and patients (using a standard questionnaire).

SETTING

Netherlands Institute for Pigmentary Disorders, Amsterdam.

PATIENTS

Patients with lesions on arms, legs, and trunk were treated on 2 symmetrical lesions for 9 months with FP alone and a combination of FP and UV-A (FP group) or with UV-A alone and a combination of FP and UV-A (UV-A group). Fluticasone propionate cream was applied once daily at about bedtime, and UV-A (10 J/cm2) exposure was twice a week. Patients attended the clinic at 3-month intervals.

RESULTS

One hundred thirty-five patients were included, 96 of whom were evaluable after 9 months. Patients not reaching the end point withdrew because of insufficient repigmentation (n = 23), decreased motivation (n = 11), or protocol violations (n = 5). No patient (irrespective of whether they withdrew) experienced any adverse effects. The FP and UV-A groups were comparable with respect to sex, age, and location of lesions. On average, combination treatment was 3 times more effective than either UV-A or FP treatment alone. In the FP group, no atrophy was seen after 9 months with either treatment. In the UV-A group, a little atrophy was detected twice: as well during UV-A treatment alone as during combination treatment.

CONCLUSIONS

Combination treatment with FP and UV-A is much more effective in reaching complete repigmentation than are FP and UV-A used alone, but large inter-individual differences occur. Fluticasone propionate, UV-A, and a combination of FP and UV-A seem to be safe for long-term treatment of vitiligo.

Association of the Köbner phenomenon with disease activity and therapeutic responsiveness in vitiligo vulgaris

OBJECTIVE

To investigate the association between the experimentally induced Kobner phenomenon (KP-e) and the Kobner phenomenon by history (KP-h), disease activity, and therapeutic responsiveness in vitiligo vulgaris.

DESIGN

Cohort study.

SETTING

An outpatient clinic.

PATIENTS

Sixty-one consecutive patients with vitiligo vulgaris.

INTERVENTION

Three months after a standardized epidermodermal injury was induced, the KP-e was evaluated. For 1 year, UV-B (311 nm) therapy or topical fluticasone propionate plus UV-A therapy was given, depending on the severity of depigmentation.

MAIN OUTCOME MEASURES

The presence or absence of the KP-e and the KP-h disease activity as scored on a 6-point scale from -1 to +4 (vitiligo disease activity [VIDA] score) and therapy-induced repigmentation grade.

RESULTS

Nineteen (31%) of the patients had a positive KP-h, whereas 37 (61%) showed a positive KP-e (P<.001). The VIDA score did not always predict a positive KP-e, although patients with a positive KP-e had a higher mean VIDA score (VIDA score of 1.6) than did patients with a negative KP-e (VIDA score of 0.5) (P<.001). The responsiveness to UV-B (311 nm) therapy among KP-e-positive or KP-e-negative patients was not significantly different (P=.66). However, KP-e-positive patients who were treated with fluticasone propionate plus UV-A showed a better response than did KP-e-negative patients (P=.01). Among patients responding to both therapies, VIDA scores were significantly decreased (P<.001) compared with VIDA scores before therapy.

CONCLUSION

The KP-e may function well as a clinical factor to assess present disease activity and may also predict the responsiveness to fluticasone propionate plus UV-A therapy but not to UV-B (311 nm) therapy.

Nonsurgical repigmentation therapies in vitiligo. Meta-analysis of the literature

OBJECTIVE

To assess the effectiveness and safety of nonsurgical repigmentation therapies in localized and generalized vitiligo by means of a meta-analysis.

DATA SOURCES

Computerized searches of bibliographic databases, a complementary manual literature search, and contacts with researchers and pharmaceutical firms.

STUDY SELECTION

Predefined selection criteria were applied to both randomized and nonrandomized controlled trials.

DATA EXTRACTION

Two investigators independently assessed the articles for inclusion. When there was a disagreement, a third investigator was consulted.

DATA SYNTHESIS

Sixty-three studies were found on therapies for localized vitiligo. Of these, 10 of 11 randomized controlled trials and 29 of 110 patient series were included. One hundred seventeen studies on therapies for generalized vitiligo were found. Of these, 10 of 22 randomized controlled trials and 46 of 231 patient series were included. Among randomized controlled trials on localized vitiligo, the pooled odds ratio vs placebo was significant for topical class 3 corticosteroids (14.32; 95% confidence interval [CI], 2.45-83.72). In the patient series, topical class 3 and class 4 corticosteroids carried the highest mean success rates (56% [95% CI, 50%-62%] and 55% [95% CI, 49%-61%], respectively). Side effects were reported mostly with topical psoralen and intralesional and class 4 corticosteroids. In the randomized controlled trials on generalized vitiligo, the odds ratio vs placebo was significant for oral methoxsalen plus sunlight (23.37; 95% CI, 1.33-409.93), oral psoralen plus sunlight (19.87; 95% CI, 2.37-166.32), and oral trioxsalen plus sunlight (3.75; 95% CI, 1.24-11.29). In the series, the highest mean success rates were achieved with narrowband UV-B (63%; 95% CI, 50%-76%), broadband UV-B (57%; 95% CI, 29%-82%), and oral methoxsalen plus UV-A therapy (51%; 95% CI, 46%-56%). Oral methoxsalen plus UV-A was associated with the highest rates of side effects. No side effects were reported with UV-B therapy.

CONCLUSIONS

Class 3 corticosteroids and UV-B therapy are the most effective and safest therapies for localized and for generalized vitiligo, respectively.

A systematic review of autologous transplantation methods in vitiligo

OBJECTIVE

A systematic review of the effectiveness, safety, and applicability of autologous transplantation methods in vitiligo.

DATA SOURCES

Computerized searches of bibliographical databases, a complementary manual literature search, and contacts with researchers and pharmaceutical firms.

STUDY SELECTION

Predefined selection criteria were applied to all studies found.

DATA EXTRACTION

Two investigators independently assessed the articles for inclusion. When there was a disagreement, a third investigator was consulted.

DATA SYNTHESIS

Sixty-three studies were found, of which 16 reported on minigrafting, 13 on split-thickness grafting, 15 on grafting of epidermal blisters, 17 on grafting of cultured melanocytes, and 2 on grafting of noncultured epidermal suspension. Of these, 39 patient series were included. The highest mean success rates (87%) were achieved with split-skin grafting (95% confidence interval, 82%-91%), and epidermal blister grafting (87%) (95% confidence interval, 83%-90%). The mean success rate of 5 culturing techniques varied from 13% to 53%. However, in 4 of the 5 culturing methods, fewer than 20 patients were studied. Minigrafting had the highest rates of adverse effects but was the easiest, fastest, and least expensive method.

CONCLUSIONS

Because no controlled trials were included, treatment recommendations should be formulated with caution. Split-thickness and epidermal blister grafting can be recommended as the most effective and safest techniques. No definite conclusions can be drawn about the effectiveness of culturing techniques because only a small number of patients have been studied. The choice of method also depends on certain disease characteristics and the availability of specialized personnel and equipment.

Repigmentation of leucodermic defects in piebaldism by dermabrasion and thin split-thickness skin grafting in combination with minigrafting

The depigmented skin areas in piebaldism are unresponsive to medical or light treatment. In 12 adult patients (eight women and four men), a method using dermabrasion and thin split-skin grafts was applied initially. Residual leucodermic areas were subsequently treated using a minigrafting method. Additional irradiation with ultraviolet A (10 J/cm2) was performed to enhance melanocyte migration. This combined surgical therapy led to 95-100% repigmentation of the leucodermic defects. A perfect colour match with the surrounding non-lesional skin was achieved in all cases. Complications were minor and easy to correct. Dermabrasion and split-skin grafting followed by minigrafting should be considered as the first choice of therapy in piebaldism.

Quantitative and objective evaluation of wound debriding properties of collagenase and fibrinolysin/desoxyribonuclease in a necrotic ulcer animal model

Proteolytic enzymes have been used for wound debridement for many years. The two enzymes most widely used in Europe are fibrinolysin/desoxyribonuclease and collagenase. Despite their frequent use, very few placebo-controlled studies comparing the enzymes with vehiculum only, or with each other, are available. In a specially developed necrotic ulcer animal model, combined with a computer image analysis technique to measure necrotic and total wound surface areas quantitatively, we assessed the wound-cleansing properties of fibrinolysin/DNase oleogel, collagenase ointment, saline-soaked gauze control treatment, and new galenic formulations of collagenase, including placebos. The average relative area of necrotic tissue present in the wound after 1 week was 31% for collagenase ointment and 56% for fibrinolysin/DNAse oleogel (P = 0.0037). Collagenase gel was significantly (P = 0.0007) better in removing necrosis than placebo (gel only). Fibrinolysin/DNAse was not significantly more effective than the three placebo or control treatments (placebo film, placebo gel, saline-soaked gauzes). We conclude that collagenase is a suitable enzyme for wound debridement, but we were not able to detect clinical efficacy of fibrinolysin/DNAse in this model.

Relative contributions of decay accelerating factor (DAF), membrane cofactor protein (MCP) and CD59 in the protection of melanocytes from homologous complement

Complement regulatory molecules, membrane cofactor protein (MCP), decay accelerating factor (DAF) and CD59, protect body cells from autologous complement. They have wide tissue distribution but nothing is known about the expression of these molecules on human melanocytes. Since melanocytes are lysed in the lesional skin of patients with a depigmentary disorder vitiligo, it is important to compare the protection offered by complement regulatory molecules to melanocytes present in normal and vitiligo epidermis, against autologous complement. From this point of view, we investigated the differential expression of MCP, DAF and CD59 on normal cultured human melanocytes and assessed their individual contribution in the protection of these cells against complement-mediated damage. Flow cytometric analysis showed that MCP and DAF but not CD59 were expressed on cultured melanocytes. When heat inactivated sera of patients with vitiligo were used as a source of anti-melanocyte antibody to sensitize melanocytes, and guinea pig serum (GpS) or normal human serum (NHS) as a source of complement, GpS was found to be more effective in causing the lysis of melanocytes than NHS. When melanocytes were sensitized with autoantibody as well as F(ab')2 fragment of either anti-MCP or anti-DAF and subsequently incubated with NHS or GpS, both antibody fragments increased the killing of melanocytes by NHS as well as by GpS. F(ab')2 fragment of anti-DAF was much more effective in causing enhancement of lysis than that of anti-MCP. Thus, cultured normal human melanocytes express functionally active MCP and DAF but not CD59. Contribution of DAF in protecting melanocytes against complement attack was much more than that of MCP.

Treatment of vitiligo with UV-B radiation vs topical psoralen plus UV-A

OBJECTIVE

To compare the efficacy and safety of 2 treatment modalities, topical psoralen plus UV-A (PUVA) with unsubstituted psoralen and 311-nm UV-B radiation, in patients with vitiligo.

DESIGN

This intervention study was designed as a before-and-after trial with 2 arms, in which patients were consecutively included.

PATIENTS

Male (n = 99) and female (n = 182) patients, who predominantly had skin type III, with extensive, generalized vitiligo of more than 3 months' duration.

INTERVENTIONS

Two patient groups were investigated. The first group of patients was treated for 4 months with either topical PUVA (n = 28) or 311-nm UV-B radiation (n = 78). The second group of patients, treated twice weekly with 311-nm UV-B radiation, was followed up for 3 (n = 60), 6 (n = 27), 9 (n = 37), or 12 months (n = 51).

RESULTS

Thirteen (46%) patients in the first group treated with topical PUVA showed repigmentation after 4 months. Fifty-two patients (67%) in the 311-nm UV-B treatment group showed repigmentation after 4 months. After 3 months, 5 patients (8%) in the second group showed more than 75% repigmentation of lesional skin compared with 32 patients (63%) after 12 months. As in other treatment modalities, the face showed good repigmentation, whereas hands and feet responded poorly. No adverse effects were encountered with treatment with narrowband UV-B radiation, contrary to those seen with topical PUVA treatment. The cumulative UV-B dose was very small compared with that of the topical PUVA treatment.

CONCLUSIONS

According to our results, the treatment of patients with vitiligo with 311-nm UV-B radiation is as efficient as with topical PUVA and has fewer adverse effects.

Efficient debridement of necrotic wounds using proteolytic enzymes derived from Antarctic krill: a double-blind, placebo-controlled study in a standardized animal wound model

Wound healing can be accelerated by removing necrotic tissue. Various methods of wound debridement have been developed, including enzymatic debridement. Recently potent proteolytic enzymes were isolated from the intestine of Euphausia superba (Antarctic krill) that might be useful for degrading necrotic tissue. The purpose of this study was to evaluate the debriding properties of krill enzymes, using a specially designed animal model and a computerized analysis system. In 10 female domestic pigs, each weighing 20 kg, 6 artificial ulcers were made on each animal's back using electrokeratome, followed by application of trichloracetic acid. Ulcers were treated twice daily for 7 days with either krill enzymes at different concentrations or with saline. Reduction of necrotic tissue was measured daily using computerized wound analysis. Histological examination included the determination of bromodeoxyuridine incorporation in order to detect cell proliferation as well as routine stains. The debriding effect of krill enzymes at a concentration of >/= 3.0 casein units per ml was significantly better than saline control treatment (p < 0.05). The effect was dose dependent, and granulation tissue formation was enhanced. In conclusion, krill enzymes are effective in wound debridement, as measured in this animal model.

Effect of nitric oxide on the adhesion of human melanocytes to extracellular matrix components

The aim of the present study was to explore whether nitric oxide (NO) interferes with the attachment of human melanocytes to the extracellular matrix (ECM) components. Consequently, the effects have been investigated of the NO-releasing compounds 3-morpholino-sydnonimine (SIN-1) and S-nitroso-glutathione (GSNO) on the in vitro adhesion of human melanocytic cells to fibronectin. The NO donors induced a concentration-dependent reduction in the adhesion of both 51CrO4(2-)-labelled melanocytes and melanoma cells to fibronectin. Pigmented M14 melanoma cells were more susceptible to the effect of SIN-1 (half-maximal inhibiting effect at about 0.5 mM) than normal human melanocytes and also than the non-pigmented melanoma cells Mel57 (half-maximal inhibiting effects between 0.9 and 2 mM). This effect of SIN-1 also appeared to be related to the melanin content of normal melanocytes, whereas GSNO was significantly less active. Both flow cytometric analysis and immunocytochemical staining showed expression of neuronal NO synthase in all cell lines. The results of this study suggest that aberrant in vivo production of NO during infection and inflammation may contribute to loss of melanocytes in, for example, vitiligo, by reducing de novo attachment of melanocytes to the ECM. These findings could also be important for understanding the process of metastasis.

Tenascin is overexpressed in vitiligo lesional skin and inhibits melanocyte adhesion

The aetiology of vitiligo remains obscure. In this study, the role of integrins in the observed inability of melanocytes to repopulate lesional skin was investigated. Antibodies directed to alpha 2, alpha 3, alpha 5, alpha v, alpha 6, beta 1 and beta 3 integrin subunits were used. Immunohistology revealed no marked differences in the overall levels of expression of integrins between control, non-lesional perilesional or lesional skin. Moreover, no differences were noted in the level of expression of integrins or the adhesive capacity between cultured control cells derived from three separate donors and vitiligo-derived melanocytes from two donors. Rather, it was clearly observed that towards the lesion, vitiligo skin contains increasing amounts of tenascin in the basal membrane and papillary dermis in five patients employing T2H5 antihuman tenascin antibody. The anti-adhesive effect observed in vitro for this extracellular matrix molecule using normal melanocytes may contribute to loss of pigment cells in vitiligo or to ineffective repopulation of the lesions.

Laser treatment for further depigmentation in vitiligo

BACKGROUND

In patients with vitiligo, sometimes the greatest part of the skin has already lost its melanocytes. The remaining pigmented patches can be removed by using strong bleaching creams, but many adverse events have been reported with this treatment. A new depigmentation therapy could be treatment with a Fluby laser.

METHODS

Before treatment, the patients filled out a questionnaire about their vitiligo history. Eight patients with remaining pigmentation of the arms, hands, and face were treated once with a Ruby laser. Patients were monitored for developing repigmentation during the 9 months after treatment.

RESULTS

In patients with a positive Koebner phenomenon, a permanent state of depigmentation was reached after laser therapy. None of the treated patients showed severe side-effects.

CONCLUSIONS

Ruby laser treatment can be an effective, fast, and safe method for removing cosmetically disturbing remnants of normal pigmentation in vitiligo patients with a positive Koebner phenomenon.

[Vitiligo]

Vitiligo is a disorder in which, owing to disappearance of melanocytes in the skin, sharply delimited, symmetrically arranged white patches develop. The condition occurs in 1-2% of the population, mostly between the ages of 10 and 30 years, and as often in males as in females. The course is usually progressive with periods of stability. A number of autoimmune diseases and dermatoses coincide with vitiligo. The cause of vitiligo is unknown. Hereditary factors, autoimmunization, neurological disorders and autodestruction have been hypothesized. Repigmentation therapy consists of photo(chemo)therapy use of corticosteroids, and transplantation of pigment cells. For patients in whom this fails and with more than 80% cutaneous involvement, total depigmentation therapy could be considered.

In vitro tissue-digesting properties of krill enzymes compared with fibrinolysin/DNAse, papain and placebo

Wound debridement, the removal of necrotic tissue, can be achieved with proteolytic enzymes. Recently, a new multi-enzyme preparation, krill enzyme, isolated from Antarctic shrimp-like organisms (Euphausia superba), was reported to possess powerful proteolytic activity towards protein substrates. In this paper, we study the in vitro digestive properties of krill enzymes towards whole tissue, compared with placebo, papain, and fibrinolysin/DNAse. Freshly obtained skin specimens were exposed for 3 days to krill enzymes (3; 0.6 and 0.06 U/ml), papain (120; 60; 6 and 0.6 U/ml), fibrinolysin/DNAse (2.5/1500 E and 1/600 E), and phosphate-buffered saline control solution. Tissue digestion was estimated by measuring wet wt, dry wt, and histological examination. After 72 hr of exposure to 3 U/ml krill enzymes, the dry wt of the specimens was reduced to 2.7% +/- 1.9 (SEM, n = 5), compared with 31.0% +/- 2.7 for placebo, 25.7% +/- 2.5 for 120 U/ml papain, and 24.5% +/- 3.3 for 2.5/1500 E/ml fibrinolysin/DNAse. The differences between krill enzymes and fibrinolysin/DNAse, papain, and control solution were statistically significant (p < 0.007). These data suggest that krill enzymes are more active than other commonly available proteolytic agents used for wound debridement.