Pyruvate-triggered TCA cycle regulation in Staphylococcus aureus promotes tolerance to betamethasone valerate.

Staphylococcus aureus is a resident skin bacterium involved in the exacerbation of atopic dermatitis. Here we report that S. aureus regulates the tricarboxylic acid (TCA) cycle via the production of pyruvate for tolerance to betamethasone valerate (BV), an anti-inflammatory drug used in the treatment of atopic dermatitis. The addition of BV or clobetasol propionate to the medium among 5 different anti-inflammatory steroids delayed the growth of S. aureus. Comprehensive gene expression analysis by RNA-seq revealed that BV increased the expression of genes related to glycolysis in S. aureus. Pyruvate, a product of glycolysis, suppressed the S. aureus growth inhibition by BV. The addition of oxaloacetate, a compound in the TCA cycle biosynthesized from pyruvate, was also suppressed the inhibitory effect of BV. Malonate, an inhibitor of succinate dehydrogenase in the TCA cycle, increased the inhibitory effect of BV on the growth of S. aureus. These findings suggest that S. aureus promotes tolerance to BV, an anti-inflammatory steroid, by regulating the TCA cycle via the production of pyruvate.

In vitro evaluation of betamethasone esters for phototoxic potential.

The phototoxicity of Betamethasone valerate and betamethasone dipropionate has been investigated on irradiation in the wavelength range of 300-400 nm, using some basic in vitro phototoxicity tests. Both esters cause photohemolysis of mouse red blood cells and photoperoxidation of linoleic acid. The photoproducts of both esters have also been found to be phototoxic. The toxicity of these photoproducts increases with further irradiation; however, they exhibit toxicity, even in the dark. The efficient inhibition of photohemolysis by the well-known free radical scavengers, such as butylhydroxyanisole and reduced glutathione, and minor inhibition by singlet-oxygen quenchers, such as sodium azide, suggests that cellular damage is mainly mediated by free radicals whereas singlet oxygen plays a minor role.

Differential effects of corticosteroids and pimecrolimus on the developing skin immune system in humans and mice.

Atopic dermatitis arises primarily in early infancy. In these patients, corticosteroids are used especially with great caution because of their side effects. Calcineurin inhibitors such as pimecrolimus (PIM) could be useful, but safety concerns have been raised in particular because of the lack of knowledge about their effects on the developing skin immune system. This study was designed to investigate the impact of PIM and corticosteroids on epidermal cells (EC) in infants and newborn mice. We found that the percentage of unfractionated viable infant ECs was significantly decreased in the presence of beta-methasone-17-valerate (BMV) but not PIM. Exposure of unfractionated infant ECs to BMV but not to PIM and vehicle control caused a significant inhibition of the upregulation of CD86 molecules on Langerhans cells (LC). The release of cytokines by LCs and ECs, cultured in the presence of BMV and PIM, was not significantly reduced compared with controls. Topical corticosteroid but not PIM application onto newborn mice induced apoptosis in some LC precursors. Our data suggest that similar to the situation in adult skin, corticosteroids may impair LC maturation as well as viability of ECs in infants, effects not seen with PIM.

[Studies on toxicity of hydrocortisone 17-butyrate 21-propionate -2. Subacute toxicity in rats by subcutaneous administration (author's transl)].

Subacute toxicity of hydrocortisone 17-butyrate 21-propionate (HBP), a new synthetic corticosteroid, was studied in rats, using betamethasone 17-valerate (BV) and hydrocortisone 17-butyrate (HB) as the reference drugs. HBP was subcutaneously injected to rats at the daily doses of 0.08, 0.4, 2.0, 10 and 50 mg/kg for 30 days. BV and HB were also administered at the daily doses of 0.08, 0.4 and 2.0 mg/kg. The recovery test was performed for 4 weeks after administration of HBP, BV and HB. The suppression of body weight gain by HBP was observed at the doses more than 0.08 mg/kg in male and more than 2.0 mg/kg in female rats. In addition, at the doses more than 0.4 mg/kg of HBP induced the dose-dependent symptoms such as decrease in the number of circulating white blood cells, lymphocyte counts and S-ALP level, increase in total cholesterol, GOT and GPT level of serum, and regressive changes in adrenals, lymphatic and hematopoietic tissues. There were fatal cases in rats given 50 mg/kg of HBP. These changes are considered to be common phenomena to other corticosteroids, and less toxic in female than male rats. Changes of symptoms caused by the administration of HBP 2.0 mg/kg were almost recovered after withdrawal. The toxicities of three corticosteroids were in the order of BV greater than HB greater than or equal to HBP in strength. As the result, maximum non-toxic dose of HBP was estimated to be 0.08 mg/kg in female and lower than that in male rats.

[Studies on antigenicity, phototoxicity and other specific toxicities of hydrocortisone 17-butyrate 21-propionate (HBP) (author's transl)].

The present experiments were undertaken to determine the antigenicity and other toxicities of HBP; such as phototoxicity, photosensitivity, ulcerogenicity, adrogenic-myotropic, estrogenic and progestational activities, and mutagenicity. No antibody formation and delayed type skin reaction of HBP were seen in rabbits. Active systemic anaphylaxis was not observed in guinea pigs challenged by HBP. In the phototoxicity and photosensitivity test, 0.1% HBP ointment, 0.1% HBP cream and 10% HBP acetone solution did not show any skin reaction with or without irradiation of ultraviolet light. Repeated subcutaneous administration of HBP irritated the gastric and intestinal mucosa dose dependently in rats as hydrocortisone 17-butyrate and betamethasone 17-valerate (BV). HBP had neither androgenic-myotropic nor estrogenic activity, but antiestrogenic activity was observed. The progestational activity of HBP in immature rabbit pretreated with estrone was less potent than BV. In the mutagenicity test os HBP investigated by the reverse mutation according to the method by Ames, no significant increase in the number of revertants was observed in the presence or absence of S9 mixture.

[Studies of toxicity of hydrocortisone 17-butyrate 21-propionate -5. Chronic toxicity in rats by percutaneous administration (author's transl)].

Chronic toxicity of a new synthetic corticosteroid, hydrocortisone 17-butyrate 21-propionate (HBP), was investigated in rats of both sexes. HBP was percutaneously given to rats with 0.1%, 0.5% cream and ointment at the daily dose level of 150 mg per 100 g body weight for 6 months. For the comparison, the percutaneous toxicity with 0.12% betamethasone 17-valerate (BV) cream and ointment, and 0.1% hydrocortisone 17-butyrate (HB) cream and ointment at the daily dose level of 150 mg per 100 g body weight were studied. Rats receiving HBP showed the dose-dependent changes such as the suppression of body weight gain and food intake, emaciation, decrease in the number of white blood cells and lymphocytes, total protein, increase in the number of red cells, hematocrit, hemoglobin, blood sugar and total cholesterol, regressive changes in adrenal cortex, lymphatic and hematopoietic tissues and skin, and gastric erosion, which have been well known as toxic effects of synthetic corticosteroids. These findings were comparatively high toxic in male, and almost disappeared in rats elapsed recovery time of month after withdrawal of HBP. The toxicities of HBP, BV and HB were qualitatively same. However, the grade of effects of HBP toxicity was similar to that of HB, weaker than of BV.