Laboratory investigations in patients with generalized psoriasis under oral retinoid treatment. A multicenter study of computerized data

Alstonia scholaris R. Br. Significantly Inhibits Retinoid-Induced Skin Irritation In Vitro and In Vivo

Topical retinoids inhibit matrix metalloproteinases and accelerate collagen synthesis, thereby triggering antiaging effects in the skin. However, topical retinoids can cause severe skin reactions, including scaling, erythema, papules, and inflammation. The present study demonstrates that the ethanolic bark extract of Alstonia scholaris R. Br. can significantly inhibit all-trans retinoic acid-induced inflammation in human HaCat keratinocyte cells. Furthermore, two representative retinoid-induced proinflammatory cytokines, monocyte chemoattractant protein-1 and interleukin-8, were significantly suppressed by A. scholaris extract (by 82.1% and 26.3% at 100 ppm, and dose-dependently across the tested concentrations) in vitro. In a cumulative irritation patch test, A. scholaris extract decreased retinol-induced skin irritation, while strengthening the ability of retinoids to inhibit matrix metalloproteinase-1 expression, which is strongly associated with aging effects. These results suggest that A. scholaris is a promising compound that may increase the antiaging function of retinoids while reducing their ability to cause skin irritation.

N-retinoyl-D-glucosamine, a new retinoic acid agonist, mediates topical retinoid efficacy with no irritation on photoaged skin

BACKGROUND

Chronic ultraviolet (UV) radiation from sunlight induces wrinkle formation. Retinoic acid (RA) can markedly improve wrinkles, although RA does have some side-effects, such as skin irritation. As the efficacy and cytotoxicity of RA has been traced to its free carboxylic acid, we synthesized a new molecule, N-retinoyl-D-glucosamine (GRA), in which a glucosamine has been attached to the polar end group of all-trans retinoic acid.

OBJECTIVES

To analyse the effect of topical GRA in wrinkle repair and anti-irritation in photoaged mice compared with topical RA, as well as to determine retinoic acid receptor (RAR) and retinoid X receptor (RXR) transactivation activity in vitro.

METHODS

Hairless mice were irradiated with 60 mJ cm-2 of UVB for 10 weeks, and then topically treated with 0.05% GRA or 0.05% RA for 8 weeks. An in vitro transcriptional assay was performed and the activity of GRA in 293 cells transfected with RAR-alpha or RXR-alpha expression plasmid and luciferase reporter plasmid then determined.

RESULTS

Topical GRA and RA brought about almost complete disappearance of the wrinkles caused by UVB irradiation. The two ligands promoted both a wide repair zone histologically, and the expression of type 1 collagen in the skin. In contrast, topical GRA treatment did not produce irritation such as erythema or roughness, or alteration of transepidermal water loss values, compared with RA. In the in vitro luciferase assay, GRA resulted in significant dose-dependent RAR transactivation activity in a 100 times higher concentration range than RA. GRA did not mediate RXR transactivation activity at all.

CONCLUSIONS

Topical GRA appears to be able to repair photoaged skin damage without any of the irritation caused by topical RA, probably via RAR transactivation activity.

In-vivo activity of retinoid esters in skin is related to in-vitro hydrolysis rate

BMS-181163 (4-acetamidophenyl retinoate, previously reported as BMY-30123), the acetamidophenyl ester of all-trans-retinoic acid (tRA), is topically active in various retinoid-sensitive animal models, but was recently shown to be ineffective for the treatment of acne in patients. To determine whether BMS-181163 functions as a prodrug of tRA in mice but not in man, the relative rates of ester hydrolysis in mouse and human skin homogenates were determined. In-vitro hydrolysis assays showed that BMS-181163 was substantially hydrolysed in mouse skin homogenates and minimally in human skin preparations. In addition, a series of phenyl esters of tRA and several known active synthetic retinoids (Ch-80: (E)-4-[3-oxo-3-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1 - propenyl] benzoic acid; CD-271: 6-[3-(1-adamantyl)-4-methyoxyphenyl]-2-naphthoic acid; and TTNPB: (E)-4-[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1- propenyl] benzoic acid) was prepared and hydrolysis rates and in-vivo (rhino mouse utriculi reduction) activities were compared. The hydrolysis rates of the six test retinoid phenyl esters, ranging from 0.06 to 2.0 h-1 were found to correlate with the in-vivo activity. Those esters (BMS-181163 and acetamidophenyl esters of Ch-80 and TTNPB) with a higher hydrolysis rate exhibited in-vivo activity only slightly lower than their parent free acid retinoids. In contrast, the three phenyl esters with a hydrolysis rate less than 0.3 h-1 were inactive in-vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Retinoic acid receptor gamma mediates topical retinoid efficacy and irritation in animal models

Among retinoic acid receptors (RARs) alpha, beta, and gamma, the messenger RNA level of RAR-gamma is the most readily detectable by Northern blotting in human and mouse skin. This observation suggests that RAR-gamma may play a critical role in the modulation of the therapeutic benefits and side effects of retinoids in skin. To test this hypothesis, 11 RAR-gamma selective retinoids were synthesized based on three related structures. Each compound was found to prefer RAR-gamma when assessed by retinoid-induced transcriptional activity (RAR-gamma > RAR-beta > RAR-alpha). The apparent Kd for binding to recombinant receptor protein was found to follow a similar trend. To correlate this receptor selectivity with in vivo activity, the compounds were tested topically in the Rhino mouse utriculi reduction and rabbit irritation models, two assays widely used to screen retinoids for efficacy and side effects, respectively. The results indicated that for these compounds, both efficacy in the utriculi reduction assay and irritation potential in rabbits correlated positively with the RAR-gamma transactivation activity, with r2 of 0.9 and 0.8, respectively. These data suggest that RAR-gamma is an important regulator of retinoic acid efficacy in skin and further, that the irritation associated with the use of retinoids is most likely a receptor-mediated process.

Retinoid hepatitis

A 65-year-old woman treated with etretinate for pityriasis rubra pilaris developed chronic active hepatitis. The elevated transaminases were noted 2 months after initiation of therapy and peaked 2 months after discontinuation of etretinate. The spectrum of liver toxicity induced by etretinate is reviewed. We suggest that reported cases of retinoid-induced liver disease can be divided into four distinct categories: nonspecific reactive hepatitis, acute hepatitis, chronic active hepatitis, and severe fibrosis or cirrhosis.

Effects of all-trans retinoic acid on UVB-irradiated and non-irradiated hairless mouse skin

The effects of all-trans retinoic acid (t-RA) on photodamaged and normal non-irradiated skin were examined in hairless mice (Skh:HR-1). After being exposed to increasing doses of UVB for 10 weeks (total dose = 1.4 J/cm2), the animals were then treated with 0.1% t-RA in ethanol (50 microliters, five times per week) for another 10 weeks. Several animals (the follow-up group) were further observed after the termination of the t-RA treatment to investigate if the t-RA effect was reversible. Wrinkle effacement induced by t-RA was compared with three other parameters: a) de novo collagen synthesis, b) width of the dermal repair zone, and c) epidermal thickening. Interestingly, t-RA did not stimulate collagen synthesis in animals not exposed to UVB. In the irradiated animals, the time course of wrinkle reduction correlated with the stimulation of collagen synthesis. After a synchronous initial lag phase of 4-6 weeks, the wrinkling decreased from the maximum grade of 4 to a mean grade of 1.3, whereas collagen synthesis was enhanced to 245% of the control at week 10 of t-RA treatment. In contrast, a similar lag phase was not observed for either the appearance of the dermal repair zone or epidermal thickening. In the follow-up group, upon termination of t-RA treatment, collagen synthesis returned to the control level. Wrinkle effacement and thickening of the dermal repair zone, however, did not regress, suggesting the anti-photoaging effect of t-RA was not reversible over this time frame. The correlation between the length of the lag phases for collagen synthesis and wrinkle reduction points to the possibility that collagen plays an important role in tRA-induced wrinkle effacement. Both parameters are thus important endpoints for investigating the mechanism of RA-induced repair of photodamaged skin.

Severe hepatotoxic reaction with progression to cirrhosis after use of a novel retinoid (acitretin)

We report the case of a 50-year-old female who suffered from severe palmar and plantar pustulosis. During treatment with acitretin, a novel oral retinoid, which is the main derivative of etretinate, the patient developed a severe hepatotoxic reaction. Subsequent histological studies strongly suggested the development of liver cirrhosis. Reversible elevation of serum aminotransferase values during treatment with acitretin has been reported. However, the present observation indicates that severe hepatotoxic injury may also follow treatment with this agent.

Pharmacokinetics of etretinate in psoriatic patients with liver fibrosis

A study of the pharmacokinetics of etretinate in 7 psoriatic patients with liver fibrosis or liver cirrhosis is reported. Maximum plasma concentrations occurred within 1.5-4.0 hr. Absorption lag-times ranged from 0.3-2.5 hr, whereas the apparent absorption first order half-times (t1/2ka) were within the range of 0.3-1.2 hr. As judged from the AUC-values corrected for dose and body weight a six-fold interindividual variation existed with regard to the systemic availability of etretinate. Absorption and disposition rates of etretinate in subjects with hepatic fibrosis increasing to cirrhosis were not significantly altered compared with previous results in psoriatic patients with normal liver function.

Etretinate in severe psoriasis of children

Ten children, five with generalized pustular psoriasis and five with erythrodermic disease, were treated with etretinate and observed for up to seven years. In all those with pustular psoriasis, complete clearing was obtained in three weeks to four months, but in one child maintenance therapy had to be introduced twice, for one year each time. In those with erythrodermic psoriasis, the results were favorable only in two, and in two it was necessary to introduce Re-PUVA. Clinical side effects were slight, and laboratory examinations did not disclose any significant abnormalities. In one child who was treated intermittently for seven years, focal osteoporosis of one tibia was disclosed by radiography. No adverse effects on children's development were noticed.

The effect of oral retinoid therapy on the normal human immune system

Twenty four patients were studied prior to and after 6 and 12 weeks therapy with isotretinoin (17 patients) for acne and related disorders, or with etretinate (7 patients) for psoriasis and related disorders. Patients treated with isotretinoin had a significant reduction in natural killer cell activity at an effector: target cell ratio of 100: 1 at 12 weeks and also a reduction in natural killer cell numbers at this time. Patients treated with etretinate had elevated natural killer cell activity and a significant elevation of natural killer cell numbers at 12 weeks. Other tests which were performed and showed no significant change at 6 or 12 weeks compared with starting levels included lymphocyte transformation in response to phytohaemagglutinin, pokeweed mitogen and concanavalin A, total numbers of circulating T lymphocytes, B lymphocytes and T helper and T suppressor subsets, numbers of epidermal Langerhans cells and serum levels of IgA, IgM and IgE. In view of the involvement of natural killer cells in the initial phase of organ rejection, these results suggest that isotretinoin is the safer of the two retinoids if administration to renal transplant recipients is considered, particularly in the immediate post-transplant period.

Liver toxicity of retinoid therapy

Vitamin A metabolism involves storage in the liver. Hypervitaminosis A results in liver abnormalities, including fibrosis and cirrhosis. Ito cells are increased and promote fibrogenesis, which results in cirrhosis. Retinoids (Accutane and Tegison) are used clinically for the treatment of a variety of skin diseases. Since retinoids are analogs of vitamin A, their potential to produce liver disease is reviewed. Animal and human studies of liver function tests suggest some abnormalities in the liver in about 25% of patients treated. Liver biopsy studies have included isolated case reports and two retrospective and one prospective liver biopsy study of retinoids in humans. Although some increase in histologic liver changes have been noted, most liver biopsy specimens showed no change or improvement. Retinoids do not appear to produce consistent toxic liver abnormalities.

Hepatocanalicular injury associated with vitamin A derivative etretinate. An idiosyncratic hypersensitivity reaction

A patient with pustular psoriasis developed jaundice, peripheral blood eosinophilia, and biochemical evidence of hepatocanalicular dysfunction four weeks after the initiation of etretinate therapy. A liver biopsy specimen showed bile duct damage, a periportal inflammatory infiltrate composed of neutrophils, eosinophils and lymphocytes, canalicular cholestasis, and focal hepatocyte necrosis. Clinical exclusion of other possible etiologic factors coupled with near resolution of the biochemical abnormalities within six weeks after complete discontinuation of the drug indicates that etretinate may induce an idiosyncratic hypersensitivity reaction. This is the first report to document etretinate associated bile duct injury.

Chronic active hepatitis associated with etretinate therapy

Acute hepatitis developed in a patient taking etretinate for severe psoriasis. Discontinuation of therapy was followed by progression of the histological changes to chronic active hepatitis, despite improvement of his clinical and laboratory status. This is the third reported case of chronic active hepatitis associated with etretinate therapy, and the second patient in our group of twenty-two etretinate-treated patients with severe psoriasis to develop clinically significant hepatic disease. Immunological evaluation revealed a marked increase in the patient's OKMI-staining population of peripheral mononuclear cells and augmentation of Con A-induced lymphocyte blastogenesis in the presence of etretinate.

Serial liver biopsies in psoriatic patients receiving long-term etretinate

Twenty psoriatic patients treated with etretinate have been followed in a prospective study of liver biopsies. Twelve patients were followed up for 3 years, with four liver biopsies each. No significant damage to the liver was found during etretinate therapy. Etretinate may be stored in the fatty tissues of the liver or other body areas for prolonged periods.

Etretinate therapy in children with severe keratinization defects

Keratinization defects can be very severe and disfiguring diseases. The development of retinoids such as etretinate has provided us with an effective symptomatic form of oral therapy for these skin conditions. Based on our own experience, we briefly outline the therapeutic potential of etretinate in various keratinization defects (lamellar ichthyosis, Netherton syndrome, Sjögren-Larsson syndrome, mal de Meleda and juvenile pityriasis rubra pilaris). The toxicology of etretinate is reviewed with special regard to the treatment of children. Bone changes such as premature closure of the growth line or other unacceptable side-effects have so far not been observed. Guidelines for patient selection and for the safe treatment of children are given.

Histologic changes in the liver during etretinate treatment

Histologic changes in the liver were evaluated in thirty-two patients with different dyskeratotic dermatoses treated with etretinate (Tigason) during an average of 24.9 months. Fatty infiltration, nuclear variability, periportal inflammation, focal necrosis, fibrosis, and cholestasis were estimated. The usual dose was 50-75 mg/day, with reduction according to efficacy and side effects. No statistically significant differences were found between a control group of thirty-five liver biopsies from psoriasis patients who had not received systemic therapy and biopsies from the patients treated with etretinate. Among the thirty-two etretinate-treated patients, six had two serial biopsies, and eight had pretreatment biopsies. No significant changes appeared during therapy.

Treatment of generalized pustular psoriasis with etretinate (Ro 10-9359) and methotrexate

A case of generalized pustular psoriasis in a severely ill patient is described. The patient's clinical course was unaltered by conservative measures, methotrexate alone or etretinate (Ro 10-9359) alone. However, with combination therapy, rapid remission of the acute phase of the illness was achieved, with eventual clearing of the skin. Methotrexate dosing was tapered, and the patient continued to do well on etretinate alone. The relatively rapid onset of action of methotrexate for treatment during the acute phase may allow time for etretinate to exert its effect and permit the use of this relatively benign drug in the long-term phase of treatment.

Etretinate in severe psoriasis. Results of double-blind study and maintenance therapy in pustular psoriasis

A randomized double-blind study was performed in forty patients with severe psoriasis. Etretinate, in contrast to placebo, clearly reduced the psoriatic area and severity index score, and this difference was statistically significant from week 2. The results in psoriasis vulgaris were satisfactory in only three of ten patients; however moderate improvement was noticed in four of ten patients. In pustular psoriasis of von Zumbusch type, the drug produced moderate improvement to complete clearing in all four of the treated patients and was regarded as the first-choice therapy in all of them. In erythrodermic psoriasis satisfactory results were obtained in four of six patients. In three of the five patients with psoriatic arthropathy there was a marked improvement of arthralgia. Laboratory investigations did not show significant abnormalities with the exception of an increase of alanine transaminase (ALT; SGPT) in about 20% of the patients. Ten patients with pustular psoriasis (four of them included in the double-blind trial) on long-term, i.e., maintenance, therapy remained free of lesions up to this writing for 3 years. Triglyceride levels were not elevated.

A dose-response study of I3-cis-retinoic acid in acne vulgaris

13-cis-retinoic acid has been used as a single agent in the treatment of seventy-six patients with previously unresponsive cystonodular acne. The study was carried out in a double-blind fashion using three doses of the drug. Ninety per cent of the patients responded with a 70% improvement in the acne severity. Sixty-six per cent of the patients experienced no further problems with their acne during follow-up. Side-effects were frequent. The 0.5 mg/kg b.w. dose is recommended for the initial course of treatment.

General clinical toxicology of oral retinoids

Four retinoids - retinol (vitamin A), tretinoin (retinoic acid), etretinate (the ethyl ester of trimethoxymethylphenyl retinoic acid), and isotretinoin (13-cis-retinoic acid, Accutane) - have been administered orally in humans for therapeutic purposes. A review of the available information on the clinical toxic effects of these substances indicated that, while they express similar spectra of toxicity, they also differ in the extent to which they affect various body systems. This suggests that differential efficacy of the retinoids may be related, in part, to the cutaneous sites of maximum activity.

A study of potential hepatotoxicity of etretinate used in the treatment of psoriasis

Etretinate was used to treat twenty patients who had severe, disabling psoriasis and an increased risk of liver damage. Potential hepatotoxicity was evaluated by obtaining liver biopsies prior to starting therapy and after a 6-month course on a dosage of 0.75 mg/kg/day. In comparing pretreatment biopsies to posttreatment biopsies, five of twenty patients demonstrated a morphologic change in their liver. Three showed progressive fatty metamorphosis, and two showed liver cell necrosis and progressive fibrosis. One of these was due to heavy alcohol intake. Based on our 6-month evaluation, etretinate does not produce a consistent toxic effect on the liver.

Severe oral lichen planus: treatment with an aromatic retinoid (etretinate)

A double-blind study of twenty-eight patients with severe oral lichen planus treated with etretinate (75 mg daily) or a placebo for 2 months, showed that the oral retinoid had a marked beneficial effect. Nine non-responders who had received only placebo then entered an open cross-over study and they responded well to etretinate. Etretinate thus provided effective symptomatic relief for severe oral lichen planus, but side-effects were common, and six patients stopped treatment because of them.

Ultrastructural evidence suggesting an immunomodulatory activity of oral retinoid. Its effect on dermal components in psoriasis

The effects of the aromatic retinoid RO 10-9359 on the fine structure of psoriatic dermis were investigated by electron microscopy in five patients after 1, 2, and 3 weeks of treatment (I mg/kg/day). Our findings show that aromatic retinoid, additionally to its epidermal effects, exerts a distinct influence on dermal components in psoriasis. Ultrastructural evidence is provided suggesting that this drug stimulates lymphocytes and monocytes, promoting their differentiation into Sézary-like lymphocytic cells, activated macrophages and dermal Langerhans cells. The appearance of these immunocompetent cell lines may modulate the cell-mediated immune response in psoriasis, obviously reflecting a pharmacological action of the drug additional to its definite influence on epidermal keratinization.

Therapeutic evaluation of the oral retinoid Ro 10-9359 in several non-psoriatic dermatoses

Forty-five patients suffering from various genodermatoses and erythematous, scaling, non-psoriatic dermatoses were treated orally with the aromatic derivative of retinoic acid, Ro 10-9359 (Tigason). In the genodermatoses the best results were obtained in ichthyosis, keratodermias and Darier's disease (95.6% good to excellent). Among the erythematous scaling diseases, treatment was effective in lichen planus, parapsoriasis and pityriasis rubra pilaris (53.3% good to excellent results). In comparison with therapies previously employed Ro 10-9359 was more effective. No serious side-effects were noted.