- Email: [email protected]
Augmented Pigmentation and Other Responses of Normal Human Skin to Solar Radiation Following Oral Administration of 8-Methoxypsoralen*†
PRELIMINARY AND SHORT REPORT AUGMENTED PIGMENTATION AND OTHER RESPONSES OF NORMAL HUMAN SKIN TO SOLAR RADIATION FOLLOWING ORAL ADMINISTRATION OF SMETHOXYPSORALEN* t THOMAS B. FITzPATRIcK, M.D., Pn.D., CARL E. HOPKINS, PH.D., DELBERT D. BLICKENSTAFF, MS. AND SHELDON SWIFT, MB., CH.B.
Clinical observations in 70 patients with vitiligo appeared to indicate that S-methoxypsoralen (S-MOP) taken orally two to three hours before exposure increased skin tolerance to ultraviolet radiation. The majority of these patients observed that the normal areas of
their skin were pigmented more intensely than usual and a few stated that the vitiligo patches showed an increased tolerance to solar radiation. In a previous study oral S-MOP was reported to decrease the erythema response of patients to artificial ultraviolet light (1). These two observations (increased tanning ability and increased skin tolerance) have been studied over the past two years in 21 volunteers with normal skin who received 20—30 mg. of S-MOP two to three hours before exposure to solar radiation in Oregon, California, Florida, Sun Valley, Idaho and the West Indies. The exposures occurred while the volunteers were vacationing or working in the sun and were therefore not controlled. The S-MOP
in this dose was observed to markedly increase tanning in all the volunteers, including those with a history of poor tanning ability. Increased tolerance to solar exposure was reported by the subjects who believed they were exposed to an intensity and duration of sunlight beyond their usual tolerance limit. To extend these clinical observations a controlled field trial with volunteer subjects was undertaken in the Arizona desert. Forty-seven healthy, adult males were selected from among the inmates of the Arizona State Prison at Florence, the sole criterion for selection being that the subject had a fair and potentially easily burned skin without previous exposure of the back for at least six months. Half of the subjects randomly allocated were given capsules containing S-MOP and the other half an identical-appearing placebo capsule. The identity of the capsules was not revealed, and the contrasting treatments were not decoded until after all evaluations of results had been made. A single dose of 50 mg. of S-MOP was given. This dose was considerably larger than the 20—30 mg. dose previously used in
clinical studies. It was thought that this higher dose level would insure maximum protection and provide clear-cut results. Three hours after ingestion of the capsules, the subjects were exposed in the prone position in direct noon-day sunlight. A small (4 inch) diamondshaped area of the back was exposed and the shield of heavy white crepe paper was applied with adhesive tape. The exposure time was 85 minutes. A second trial was made in which the capsules were switched, so that on each subject we had a contrast between the effects of the placebo and the S-MOP. The variance between subjects was considerable, but the crossover design using each subject as his own control greatly reduced the variance of the difference between the placebo and 8-MOP. Direct visual readings were made on the exposed areas at 6 hours, 20 hours, 44 hours, 66 hours and one week after exposure. At each reading, ratings were made of erythema, edema, tenderness, pigmentation, vesicles and scaling on a five point equal interval scale of 0, 1, 2, 3,4. * From the Division of Dermatology and Department of Public Health and Preventive Medicine, University of Oregon Medical School, Portland, Oregon
t This investigation was supported in part by the Medical Research Foundation of
Oregon and the Paul B. Elder Company, Bryan, Ohio. Received for publication August 19, 1955. 187
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
188
The readings showed significant differences between the placebo and 8-MOP treatments as follows: 1. Significant differences do not show up until about 44 hours after exposure. 2. At 44 hours post-exposure, erythema and tenderness are significantly greater on the 8-MOP subjects. 3. At one week after exposure the skin responses had disappeared in the placebo group, except for tanning, but there was significant erythema, edema and tenderness in the 8-MOP group.
A final reading was made at two weeks. On these readings there appeared to be considerably more vesiculation and scaling on the 8-MOP group than with the placebo. No significant difference in pigmentation was detected between the groups until the two-week reading. At this time it appeared that the 8-MOP treatment left a deeper residual pigmentation, but it was not possible to evaluate this statistically because of severe sloughing and consequent depigmentation on 22 of the 47 subjects. Of these depigmeated subjects, 18 showed the depigmentatioa on the 8-MOP areas, and only 4 on the placebo areas. This difference is significant.
The Arizona field trial provided evidence that 50 mg. 8-MOP taken three hours before exposure augments all cutaneous responses to solar radiation. In view of the fact that patients with vitiligo and normal subjects had noted increased tolerance to sunlight and in order to resolve these conflicting observations, we have carried out a series of field trials in Oregon during the recent summer months. These trials have been performed at sea level and on Mt. Hood, and we have used lower doses of the drug in order to approximate our experiments with the schedules which were used by the vitiligo and normal subjects. Controlled experiments have been made with 14 normal volunteers using from 10 to 75
-
;k
-
t
-.
-if
•4
4
44Cr
I
J4
mg. 8-MOP taken two to three hours before exposure to solar radiation. Two separate exposures of previously unirradiated skin were made in the same subject, one without the
Fin. 1. Ingestion of 75 mg. 8-MOP followed by hourly exposures to sunlight. Blistering has occurred in the area exposed two hours after taking the drug.
SKJN RESPONSES AFTER INGESTION OF 8-METHOXYPSORALEN
189
drug (control) and a second exposure two hours after ingestion of 8-MOP. Exposures were
symmetrically spaced around solar noon and equivalent intensities were estimated with an Epley pyrheliometer. The results indicate that with a dose of 10—30 mg., exposure to solar radiation for not more than one hour will produce erythema followed by increased tanning without tenderness or exfoliation. In higher doses the erythema becomes progressively greater with increasing edema followed by exfoliation. Seventy-five mg. 8-MOP followed by exposure for one hour produced marked tenderness and edema followed by blistering (Fig. 1). The augmented tanning response using 8-MOP is demonstrated by the following experiment. Two volunteers were exposed to one hour of solar radiation daily taking 30mg. 8-MOP
two hours before exposure and placebo capsules on alternate days. Each area received a total of three hours exposure. After six days photographs were made (Fig. 2). The augmentation of tanning witbout other skin changes is clearly apparent by comparing the two areas of exposure.
From these observations we must conclude that 8-MOP does not have a primary protective action but rather augments all cutaneous responses. The "protection" reported by volunteer subjects may be related to the marked increased pigmentation which occurs after oral use of 8-MOP and repeated daily exposures to ultraviolet radiant energy. Increased tolerance to sunlight would he especially apparent in those individuals who have a poor tanning ability and who develop a marked increased tanning response while using 8-MOP. Thomson (2) has recently emphasized the important role of melanin pigment in the skin as a protective mechanism against ultraviolet radiation. Although 8-MOP may have a potential use in increasing skin pigmentation and thus skin tolerance to sunlight, general use of the drug for this purpose is not recommended at
8-MOP
105 Fig. 2. Area 124 was exposed for one hour on three separate days two hours after ingestion of 30 mg. 8-MOP. Note marked increased tanning without exfoliation. Area 105 was exposed for one hour on three alternate days while the patient received placebo capsules two hours before exposure. This area represents the patient's normal tanning response.
190
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
the present time. Further controlled field trials with a larger number of subjects may be required to detect variations of response between individuals. We express our gratitude to Warden Eyman of the Arizona State Prison, Florence, Arizona, and to the inmates for their excellent cooperation in the field trial. Dr. Otis Miller, Tucson, Arizona, gave valuable assistance in the selection of the inmates aud in the grading of the results.
REFERENCES 1. LERNER, A. B., DENTON, C. R., AND FITZPATRICK, T. B.: Clinical and experimental
studies with S-methoxypsoralen in vitiligo. J. Invest. Dermat., 20: 299, 1953. 2. THoMsoN, M.: Relative efficiency of pigment and horny layer thickness in protecting the skin of Europeans and Africans against solar ultraviolet radiation. J. Physiol., 127: 236, 1955.
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
94
linolenic acid extract. Arch. This pdf is a scanned copy UV of irradiated a printed document.
24. Wynn, C. H. and Iqbal, M.: Isolation of rat
skin lysosomes and a comparison with liver Path., 80: 91, 1965. and spleen lysosomes. Biochem. J., 98: lOP, 37. Nicolaides, N.: Lipids, membranes, and the 1966.
human epidermis, p. 511, The Epidermis
Eds., Montagna, W. and Lobitz, W. C. Acascopic localization of acid phosphatase in demic Press, New York. human epidermis. J. Invest. Derm., 46: 431, 38. Wills, E. D. and Wilkinson, A. E.: Release of 1966. enzymes from lysosomes by irradiation and 26. Rowden, C.: Ultrastructural studies of kerathe relation of lipid peroxide formation to tinized epithelia of the mouse. I. Combined enzyme release. Biochem. J., 99: 657, 1966. electron microscope and cytochemical study 39. Lane, N. I. and Novikoff, A. B.: Effects of of lysosomes in mouse epidermis and esoarginine deprivation, ultraviolet radiation and X-radiation on cultured KB cells. J. phageal epithelium. J. Invest. Derm., 49: 181, 25. Olson, R. L. and Nordquist, R. E.: Ultramicro-
No warranty is given about the accuracy of the copy.
Users should refer to the original published dermal cells. Nature, 216: 1031, 1967. version of1965. the material. vest. Derm., 45: 448, 28. Hall, J. H., Smith, J. G., Jr. and Burnett, S. 41. Daniels, F., Jr. and Johnson, B. E.: In prepa1967.
Cell Biol., 27: 603, 1965.
27. Prose, P. H., Sedlis, E. and Bigelow, M.: The 40. Fukuyama, K., Epstein, W. L. and Epstein, demonstration of lysosomes in the diseased J. H.: Effect of ultraviolet light on RNA skin of infants with infantile eczema. J. Inand protein synthesis in differentiated epi-
C.: The lysosome in contact dermatitis: A ration. histochemical study. J. Invest. Derm., 49: 42. Ito, M.: Histochemical investigations of Unna's oxygen and reduction areas by means of 590, 1967. 29. Pearse, A. C. E.: p. 882, Histochemistry Theoultraviolet irradiation, Studies on Melanin, retical and Applied, 2nd ed., Churchill, London, 1960.
30. Pearse, A. C. E.: p. 910, Histacheini.stry Thearetscal and Applied, 2nd ed., Churchill, London, 1960.
31. Daniels, F., Jr., Brophy, D. and Lobitz, W. C.: Histochemical responses of human skin fol-
lowing ultraviolet irradiation. J. Invest. Derm.,37: 351, 1961.
32. Bitensky, L.: The demonstration of lysosomes by the controlled temperature freezing section method. Quart. J. Micr. Sci., 103: 205, 1952.
33. Diengdoh, J. V.: The demonstration of lysosomes in mouse skin. Quart. J. Micr. Sci., 105: 73, 1964.
34. Jarret, A., Spearman, R. I. C. and Hardy, J. A.:
Tohoku, J. Exp. Med., 65: Supplement V, 10, 1957.
43. Bitcnsky, L.: Lysosomes in normal and pathological cells, pp. 362—375, Lysasames Eds., de Reuck, A. V. S. and Cameron, M. Churchill, London, 1953.
44. Janoff, A. and Zweifach, B. W.: Production of inflammatory changes in the microcirculation by cationic proteins extracted from lysosomes. J. Exp. Med., 120: 747, 1964.
45. Herion, J. C., Spitznagel, J. K., Walker, R. I. and Zeya, H. I.: Pyrogenicity of granulocyte lysosomes. Amer. J. Physiol., 211: 693, 1966.
46. Baden, H. P. and Pearlman, C.: The effect of ultraviolet light on protein and nucleic acid synthesis in the epidermis. J. Invest. Derm.,
Histochemistry of keratinization. Brit. J. 43: 71, 1964. Derm., 71: 277, 1959. 35. De Duve, C. and Wattiaux, R.: Functions of 47. Bullough, W. S. and Laurence, E. B.: Mitotic control by internal secretion: the role of lysosomes. Ann. Rev. Physiol., 28: 435, 1966. the chalone-adrenalin complex. Exp. Cell. 36. Waravdekar, V. S., Saclaw, L. D., Jones, W. A. and Kuhns, J. C.: Skin changes induced by
Res., 33: 176, 1964.
Clinical observations in 70 patients with vitiligo appeared to indicate that S-methoxypsoralen (S-MOP) taken orally two to three hours before exposure increased skin tolerance to ultraviolet radiation. The majority of these patients observed that the normal areas of
their skin were pigmented more intensely than usual and a few stated that the vitiligo patches showed an increased tolerance to solar radiation. In a previous study oral S-MOP was reported to decrease the erythema response of patients to artificial ultraviolet light (1). These two observations (increased tanning ability and increased skin tolerance) have been studied over the past two years in 21 volunteers with normal skin who received 20—30 mg. of S-MOP two to three hours before exposure to solar radiation in Oregon, California, Florida, Sun Valley, Idaho and the West Indies. The exposures occurred while the volunteers were vacationing or working in the sun and were therefore not controlled. The S-MOP
in this dose was observed to markedly increase tanning in all the volunteers, including those with a history of poor tanning ability. Increased tolerance to solar exposure was reported by the subjects who believed they were exposed to an intensity and duration of sunlight beyond their usual tolerance limit. To extend these clinical observations a controlled field trial with volunteer subjects was undertaken in the Arizona desert. Forty-seven healthy, adult males were selected from among the inmates of the Arizona State Prison at Florence, the sole criterion for selection being that the subject had a fair and potentially easily burned skin without previous exposure of the back for at least six months. Half of the subjects randomly allocated were given capsules containing S-MOP and the other half an identical-appearing placebo capsule. The identity of the capsules was not revealed, and the contrasting treatments were not decoded until after all evaluations of results had been made. A single dose of 50 mg. of S-MOP was given. This dose was considerably larger than the 20—30 mg. dose previously used in
clinical studies. It was thought that this higher dose level would insure maximum protection and provide clear-cut results. Three hours after ingestion of the capsules, the subjects were exposed in the prone position in direct noon-day sunlight. A small (4 inch) diamondshaped area of the back was exposed and the shield of heavy white crepe paper was applied with adhesive tape. The exposure time was 85 minutes. A second trial was made in which the capsules were switched, so that on each subject we had a contrast between the effects of the placebo and the S-MOP. The variance between subjects was considerable, but the crossover design using each subject as his own control greatly reduced the variance of the difference between the placebo and 8-MOP. Direct visual readings were made on the exposed areas at 6 hours, 20 hours, 44 hours, 66 hours and one week after exposure. At each reading, ratings were made of erythema, edema, tenderness, pigmentation, vesicles and scaling on a five point equal interval scale of 0, 1, 2, 3,4. * From the Division of Dermatology and Department of Public Health and Preventive Medicine, University of Oregon Medical School, Portland, Oregon
t This investigation was supported in part by the Medical Research Foundation of
Oregon and the Paul B. Elder Company, Bryan, Ohio. Received for publication August 19, 1955. 187
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
188
The readings showed significant differences between the placebo and 8-MOP treatments as follows: 1. Significant differences do not show up until about 44 hours after exposure. 2. At 44 hours post-exposure, erythema and tenderness are significantly greater on the 8-MOP subjects. 3. At one week after exposure the skin responses had disappeared in the placebo group, except for tanning, but there was significant erythema, edema and tenderness in the 8-MOP group.
A final reading was made at two weeks. On these readings there appeared to be considerably more vesiculation and scaling on the 8-MOP group than with the placebo. No significant difference in pigmentation was detected between the groups until the two-week reading. At this time it appeared that the 8-MOP treatment left a deeper residual pigmentation, but it was not possible to evaluate this statistically because of severe sloughing and consequent depigmentation on 22 of the 47 subjects. Of these depigmeated subjects, 18 showed the depigmentatioa on the 8-MOP areas, and only 4 on the placebo areas. This difference is significant.
The Arizona field trial provided evidence that 50 mg. 8-MOP taken three hours before exposure augments all cutaneous responses to solar radiation. In view of the fact that patients with vitiligo and normal subjects had noted increased tolerance to sunlight and in order to resolve these conflicting observations, we have carried out a series of field trials in Oregon during the recent summer months. These trials have been performed at sea level and on Mt. Hood, and we have used lower doses of the drug in order to approximate our experiments with the schedules which were used by the vitiligo and normal subjects. Controlled experiments have been made with 14 normal volunteers using from 10 to 75
-
;k
-
t
-.
-if
•4
4
44Cr
I
J4
mg. 8-MOP taken two to three hours before exposure to solar radiation. Two separate exposures of previously unirradiated skin were made in the same subject, one without the
Fin. 1. Ingestion of 75 mg. 8-MOP followed by hourly exposures to sunlight. Blistering has occurred in the area exposed two hours after taking the drug.
SKJN RESPONSES AFTER INGESTION OF 8-METHOXYPSORALEN
189
drug (control) and a second exposure two hours after ingestion of 8-MOP. Exposures were
symmetrically spaced around solar noon and equivalent intensities were estimated with an Epley pyrheliometer. The results indicate that with a dose of 10—30 mg., exposure to solar radiation for not more than one hour will produce erythema followed by increased tanning without tenderness or exfoliation. In higher doses the erythema becomes progressively greater with increasing edema followed by exfoliation. Seventy-five mg. 8-MOP followed by exposure for one hour produced marked tenderness and edema followed by blistering (Fig. 1). The augmented tanning response using 8-MOP is demonstrated by the following experiment. Two volunteers were exposed to one hour of solar radiation daily taking 30mg. 8-MOP
two hours before exposure and placebo capsules on alternate days. Each area received a total of three hours exposure. After six days photographs were made (Fig. 2). The augmentation of tanning witbout other skin changes is clearly apparent by comparing the two areas of exposure.
From these observations we must conclude that 8-MOP does not have a primary protective action but rather augments all cutaneous responses. The "protection" reported by volunteer subjects may be related to the marked increased pigmentation which occurs after oral use of 8-MOP and repeated daily exposures to ultraviolet radiant energy. Increased tolerance to sunlight would he especially apparent in those individuals who have a poor tanning ability and who develop a marked increased tanning response while using 8-MOP. Thomson (2) has recently emphasized the important role of melanin pigment in the skin as a protective mechanism against ultraviolet radiation. Although 8-MOP may have a potential use in increasing skin pigmentation and thus skin tolerance to sunlight, general use of the drug for this purpose is not recommended at
8-MOP
105 Fig. 2. Area 124 was exposed for one hour on three separate days two hours after ingestion of 30 mg. 8-MOP. Note marked increased tanning without exfoliation. Area 105 was exposed for one hour on three alternate days while the patient received placebo capsules two hours before exposure. This area represents the patient's normal tanning response.
190
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
the present time. Further controlled field trials with a larger number of subjects may be required to detect variations of response between individuals. We express our gratitude to Warden Eyman of the Arizona State Prison, Florence, Arizona, and to the inmates for their excellent cooperation in the field trial. Dr. Otis Miller, Tucson, Arizona, gave valuable assistance in the selection of the inmates aud in the grading of the results.
REFERENCES 1. LERNER, A. B., DENTON, C. R., AND FITZPATRICK, T. B.: Clinical and experimental
studies with S-methoxypsoralen in vitiligo. J. Invest. Dermat., 20: 299, 1953. 2. THoMsoN, M.: Relative efficiency of pigment and horny layer thickness in protecting the skin of Europeans and Africans against solar ultraviolet radiation. J. Physiol., 127: 236, 1955.
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
94
linolenic acid extract. Arch. This pdf is a scanned copy UV of irradiated a printed document.
24. Wynn, C. H. and Iqbal, M.: Isolation of rat
skin lysosomes and a comparison with liver Path., 80: 91, 1965. and spleen lysosomes. Biochem. J., 98: lOP, 37. Nicolaides, N.: Lipids, membranes, and the 1966.
human epidermis, p. 511, The Epidermis
Eds., Montagna, W. and Lobitz, W. C. Acascopic localization of acid phosphatase in demic Press, New York. human epidermis. J. Invest. Derm., 46: 431, 38. Wills, E. D. and Wilkinson, A. E.: Release of 1966. enzymes from lysosomes by irradiation and 26. Rowden, C.: Ultrastructural studies of kerathe relation of lipid peroxide formation to tinized epithelia of the mouse. I. Combined enzyme release. Biochem. J., 99: 657, 1966. electron microscope and cytochemical study 39. Lane, N. I. and Novikoff, A. B.: Effects of of lysosomes in mouse epidermis and esoarginine deprivation, ultraviolet radiation and X-radiation on cultured KB cells. J. phageal epithelium. J. Invest. Derm., 49: 181, 25. Olson, R. L. and Nordquist, R. E.: Ultramicro-
No warranty is given about the accuracy of the copy.
Users should refer to the original published dermal cells. Nature, 216: 1031, 1967. version of1965. the material. vest. Derm., 45: 448, 28. Hall, J. H., Smith, J. G., Jr. and Burnett, S. 41. Daniels, F., Jr. and Johnson, B. E.: In prepa1967.
Cell Biol., 27: 603, 1965.
27. Prose, P. H., Sedlis, E. and Bigelow, M.: The 40. Fukuyama, K., Epstein, W. L. and Epstein, demonstration of lysosomes in the diseased J. H.: Effect of ultraviolet light on RNA skin of infants with infantile eczema. J. Inand protein synthesis in differentiated epi-
C.: The lysosome in contact dermatitis: A ration. histochemical study. J. Invest. Derm., 49: 42. Ito, M.: Histochemical investigations of Unna's oxygen and reduction areas by means of 590, 1967. 29. Pearse, A. C. E.: p. 882, Histochemistry Theoultraviolet irradiation, Studies on Melanin, retical and Applied, 2nd ed., Churchill, London, 1960.
30. Pearse, A. C. E.: p. 910, Histacheini.stry Thearetscal and Applied, 2nd ed., Churchill, London, 1960.
31. Daniels, F., Jr., Brophy, D. and Lobitz, W. C.: Histochemical responses of human skin fol-
lowing ultraviolet irradiation. J. Invest. Derm.,37: 351, 1961.
32. Bitensky, L.: The demonstration of lysosomes by the controlled temperature freezing section method. Quart. J. Micr. Sci., 103: 205, 1952.
33. Diengdoh, J. V.: The demonstration of lysosomes in mouse skin. Quart. J. Micr. Sci., 105: 73, 1964.
34. Jarret, A., Spearman, R. I. C. and Hardy, J. A.:
Tohoku, J. Exp. Med., 65: Supplement V, 10, 1957.
43. Bitcnsky, L.: Lysosomes in normal and pathological cells, pp. 362—375, Lysasames Eds., de Reuck, A. V. S. and Cameron, M. Churchill, London, 1953.
44. Janoff, A. and Zweifach, B. W.: Production of inflammatory changes in the microcirculation by cationic proteins extracted from lysosomes. J. Exp. Med., 120: 747, 1964.
45. Herion, J. C., Spitznagel, J. K., Walker, R. I. and Zeya, H. I.: Pyrogenicity of granulocyte lysosomes. Amer. J. Physiol., 211: 693, 1966.
46. Baden, H. P. and Pearlman, C.: The effect of ultraviolet light on protein and nucleic acid synthesis in the epidermis. J. Invest. Derm.,
Histochemistry of keratinization. Brit. J. 43: 71, 1964. Derm., 71: 277, 1959. 35. De Duve, C. and Wattiaux, R.: Functions of 47. Bullough, W. S. and Laurence, E. B.: Mitotic control by internal secretion: the role of lysosomes. Ann. Rev. Physiol., 28: 435, 1966. the chalone-adrenalin complex. Exp. Cell. 36. Waravdekar, V. S., Saclaw, L. D., Jones, W. A. and Kuhns, J. C.: Skin changes induced by
Res., 33: 176, 1964.