Treatment of Vitiligo
Drawbacks of Traditional Methods of Treatment: A handful of treatment methods for vitiligo exist, though none have proven entirely satisfactory. Despite long treatment periods of 1-2 years (or longer), only half of the patients who undergo treatment by the existing methods respond and see any improvement. Of those who do respond, the rate of complete repigmentation is extremely low. Treatment on lips, palms, and fingers is also problematic under these methods. The use of psoralens plus UV-A or steroid therapy also produce many undesirable side effects Areas affected by vitiligo appear white, as the melanocytes in this skin are non-functional and melanin, the major causative agent of skin coloring, is absent. In order to restore new, functional melanocytes to the affected areas, new cells would have to be generated either from hair follicles surrounding the border of the vitiligo patch or from within the patch itself. If generated outside of the patch, these new cells would also need to migrate towards the affected patch and occupy the dermal epidermal junction if the patch were to ultimately reacquire pigment. Melgain® is capable of multiplying melanocytes from hair follicles surrounding the affected skin and also acts as a chemo tactic agent to direct the new melanocytes to the vitiligo patch. In attempts to better understand vitiligo for the development of a new, more effective and safer treatment, early research efforts focused on determining if melanocytes are present in vitiligo affected areas. Contrary to the then prevailing opinion, that the melanin-producing melanocytes responsible for the color of skin, hair and eyes were indeed present in the vitiligo areas. Research then began to explore why the melanoctyes, if present in vitiligo affected areas, were not producing melanin. Having successfully cultured melanocytes from untreated vitiligo patients in vitro, researchers were able to show that these cells had abnormal growth characteristics as compared to the melanocytes of healthy subjects. Adding 100,000 g supernatant of homogenates of in vitro-grown fibroblasts to the cultured cells was proven to partially correct these abnormal growth characteristics. These studies helped suggest that the absence of growth factors, like basic fibroblast growth factor (bFGF), in the skin could result in vitiligo. Animal models were then developed to test 1) the efficacy of interdermal injection of bFGF and 2) the efficacy of local application in a suitable vehicle of the various shorter peptides derives from bFGF on the rate of repigmentation. These studies assessed the rate of repigmentation in treated depigmented ear lobes of guinea pigs and skin of Yucatan swine. A total of 8 peptides ranging from 10 to 24 amino acid long-peptides were tested for their efficacy on local application; all of them were found successful in repigmenting the depigmented patches in the experimental animals. The active fragments of bFGF are specific, as other growth factors like epidermal growth factor or peptide 1-12 of bFGF did not have any effect on repigmenting the de-pigmented patches on the experimental animals.
Research Supporting Product Development: The fundamental question to answer was to find whether or not the melanocytes are present in the vitiligo patch of skin. Contrary to the then prevailing opinion, the laboratory at AIIMS established that the melanocytes which produce the melanin pigment and which were mainly responsible for the color of skin, hair and eyes were indeed present in the vitiligo patch. But then, why melanin pigment was not produced in the vitiligo skin making it chalk white was the question to answer. This led them to culture the melanocytes successfully in invitro from vitiligo patients. They demonstrated that the melanocytes from untreated vitiligo subjects have abnormal growth characteristics as compared to the melanocytes from the healthy normal subjects. These abnormal growth characterstics could be partially corrected by the addition of 100,000 g supernatant of homogenates of invitro grown fibroblasts to the growth medium of melanocytes obtained from the untreated vitiligo subjects. Based on these studies and on the effect of serum from the successfully treated vitiligo patients they postulated that growth factors like basic fibroblast growth factor (bFGF) or other mitogen deprivation in the skin of vitiligo patch could result in vitiligo. They then developed an animal model resembling vitiligo to test the efficacy of interdermal injection of bFGF on the rate of repigmentation of depigmented ear lobes of guinea pigs and depigmented skin patches of yucatan swine. This further led them to test the efficacy of local application in a suitable vehicle of the various shorter peptides derived from bFGF on the rate of repigmentation of depigmented skin patches on guinea pig ear lobes and on yucatan swine. They thus tested 8 peptides ranging from decapeptide to 24 aminoacid long peptides for their efficacy on local application. All of them were found successful in repigmenting the depigmented patches in the experimental animals. The active fragments of bFGF were shown to be specific since other growth factors like epidermal growth factor or peptide 1-12 of bFGF did not have any effect on the repigmenting depigmented patches on the experimental animals. The comparison of photographs before and during treatment of vitiligo affected volunteers during the clinical trials can be seen here. |
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