In vitro and in vivo modulation of alpha- and beta-glucocorticoid-receptor mRNA in human bronchial epithelium

Despite the central role bronchial epithelial cells play in asthmatic reactions, and the widespread use of inhaled corticosteroids in asthma, no information is available on the effect of glucocorticoids on glucocorticoid- receptor (GR) gene expression. In this study, the effect of budesonide on alpha- and beta-GR gene expression in human bronchial epithelial cells was investigated in vitro and in vivo. A bronchial epithelial cell line was exposed in vitro to budesonide, and a dose- and time-dependent synchronous downregulation of alpha- and beta-GR mRNA was observed. A 1-h exposure resulted in a reversible and reduced downregulation as compared with continuous exposure. In healthy volunteers (n = 10), no difference on average was present in GR mRNA expression before or after 4 wk of budesonide inhalation in either bronchial epithelial cells or alveolar macrophages. The time between the last inhalation and sampling of cells ranged from 0.5 to 8 h. However, a significant downregulation of alpha-GR mRNA was observed when the time between the last inhalation and sampling of cells was more than 2 h. Normalization of the downregulation of GR mRNA expression in bronchial epithelial cells is explained by the pharmacokinetics of inhaled budesonide in the human lung.

Highlights of the year in gastroenterology

The past 12 months have been a period of steady progress in the field of gastroenterology. Helicobacter pylori continues to dominate many areas of clinical research and the indications for eradication are increasing. A potent, topically-acting corticosteroid for Crohn's disease, and new hope and potential treatments for IBS sufferers are other developments.

Evaluation of the proposed FDA pilot dose-response methodology for topical corticosteroid bioequivalence testing

PURPOSE

The American FDA has recently released a Guidance document for topical corticosteroid bioequivalence testing. The purpose of this study was to evaluate the recommendations of this document for appropriateness. The new specifications require a dose-vasoconstriction response estimation by the use of a Minolta chromameter in a preliminary pilot study to determine the parameters for use in a pivotal bioequivalence study.

METHODS

The visually-assessed human skin balancing assay methodology routinely practiced in our laboratories was modified to comply with the requirements of the pilot study so that visual and chromameter data could be compared. Two different cream formulations, each containing 0.12% betamethasone 17-valerate, were used for this comparison.

RESULTS

Visual data showed the expected rank order of AUC values for most dose durations whereas the chromameter data did not show similar results. The expected rank order of AUC values for both chromameter and visual data was not observed at very short dose durations. In fitting the data to pharmacodynamic models, equivalent goodness of fit criteria were obtained when several different parameter estimates were used in the model definition, however the visual data were best described by the sigmoid Emax model while the chromameter data were best described by the simple Emax model.

CONCLUSIONS

The Emax values predicted by the models were close to the observed values for both data sets and in addition, excellent correlation between the AUC values and the maximum blanching response (Rmax) (r > 0.95) was noted for both methods of assessment. The chromameter ED50 values determined in this study were approximately 2 hours for both preparations. At this dose duration the instrument would not be sensitive enough to distinguish between weak blanching responses and normal skin for bioequivalence assessment purposes.

[Phimosis can be treated with local steroids]

The effectiveness of topical steroid application in relieving phimosis was studied in 41 boys treated with a potent steroid ointment. 35 patients showed improvement initially but in 12 of them the phimosis recurred completely and in seven of them partly. There was significantly less recurrence in the patients who improved within one month. Most of the families were satisfied with the treatment. We recommend topical steroids as first treatment of choice for phimosis, when treatment is necessary.

Aerosol therapy in patients with cystic fibrosis

Aerosol therapy is one of the mainstays of treatment, together with regular physiotherapy, in patients with cystic fibrosis. Inhalation can contribute to hydration of the epithelial lining fluid as well as delivering different drugs directly to the lungs. Topically administered antibiotics can protect the lungs from Pseudomonas infection, recombinant DNase, amiloride and beta-agonists can have a positive effect on the mucociliary clearance, and steroid inhalations can reduce inflammation. Therefore, all these drugs are part of a comprehensive treatment strategy contributing to improvement in lung function and quality of life. Gene therapy and pharmacological correction of the chloride channel defect are perspectives for the future. Aerosol therapy, however, is somewhat cumbersome and requires strict patient education.

Ragweed allergic rhinitis and the paranasal sinuses. A computed tomographic study

OBJECTIVE

To explore the potential association of allergic rhinitis and sinusitis.

DESIGN

Prospective clinical trial.

SETTING

Academic tertiary referral center.

PARTICIPANTS

Ten subjects with symptomatic ragweed allergy during the peak of the ragweed season.

MAIN OUTCOME MEASURES

We obtained a paranasal sinus computed tomographic scan on all volunteers and had them complete a modified Rhinitis Quality of Life Questionnaire. All subjects were then treated with intranasal aqueous beclomethasone dipropionate (168 micrograms twice a day) and completed the Rhinitis Quality of Life Questionnaire weekly until the end of the study.

RESULTS

Six of 10 of the subjects had sinus mucosal thickening on computed tomographic scan. All subjects improved symptomatically. A second computed tomographic scan was obtained after the pollen season in 5 patients with mucosal abnormalities, while the patients continued treatment with intranasal steroids and symptomatically improved. The sinus mucosal abnormalities persisted in all patients.

CONCLUSION

Despite the 60% incidence of abnormalities on the computed tomographic scans of the subjects with ragweed allergy during the season, these abnormalities appear, at most, to contribute minimally to the patient's symptoms, since resolution of symptoms was not accompanied by a reduction in sinus mucosal abnormalities.

Triamcinolone improves outcome in Crohn's disease strictures

PURPOSE

This study was undertaken to examine the effect of local injection of potent steroids on recurrence of Crohn's disease strictures.

METHODS

Ten patients with colonic strictures attributable to Crohn's disease were treated by dilation and injection of triamcinolone. Five of them had postoperative strictures.

RESULTS

Patients were followed for 1.5 to 3 years. Two patients required additional dilation and injection of steroids after one year. Eight patients remained well.

CONCLUSION

Local injection of steroids improves outcome in strictures caused by Crohn's disease.

Glucocorticoids induce beta2-adrenergic receptor function in human nasal mucosa

Glucocorticoids are hypothesized to induce beta2-adrenergic receptors (beta2-R) and their functions. The ability of dexamethasone (DEX) in vitro and beclomethasone dipropionate (BDP) in vivo to induce beta2-R messenger RNA (mRNA) and function was investigated in human nasal mucosa. In this tissue, albuterol does not stimulate exocytosis either in vivo or in vitro (Mullol and coworkers, 1992). Therefore, induction of beta2-R-mediated glandular exocytosis by glucocorticoids was proposed as an unambiguous outcome measure. Human nasal mucosa was cultured for 3 d with and without 1 microM DEX, then challenged with media or 100 microM albuterol. Culture supernatants were collected for measurement of exocytosed glandular products. Explant mRNA was extracted for reverse transcriptase-polymerase chain reaction (RT-PCR), and in situ hybridization of beta2-R mRNA performed. In vivo, normal subjects received saline or BDP for 3 d before albuterol nasal provocation. Concentrations of exocytosed products were measured in nasal secretions. RNA was extracted from nasal epithelial scrapings for RT-PCR. In vitro, DEX treatment induced albuterol-mediated glandular exocytosis (p < 0.04), and increased the steady-state beta2-R/beta-actin mRNA ratio (p < 0.05), and expression of beta2-R mRNA in glands. In vivo, BDP increased the beta2-R/beta-actin mRNA ratio in epithelial scrapings (p < 0.04), but did not induce albuterol-mediated glandular secretion. We conclude that glucocorticoids increase steady-state beta2-R mRNA levels in vivo and in vitro, and can induce beta2-R function as assessed by submucosal gland exocytosis in vitro. While topical BDP induced epithelial beta2-R mRNA, it did not modulate exocytosis from the deeper submucosal glands.

Interleukin-10- and corticosteroid-induced reduction in type I procollagen in a human ex vivo scar culture

Fibroblasts act as the effector cells of the fibrotic response via production of collagen. In an attempt to understand the regulation of fibroblasts from areas of active human tissue fibrosis, we have developed an ex vivo model in which biopsies of scars from patients 6 weeks post thoracotomy were cultured. This model has been used to investigate whether interleukin-10 (IL-10) and triamcinolone acetonide modulate the expression of type I procollagen mRNA and protein. In situ hybridization and a quantitative competitive RT-PCR were used to measure type I procollagen mRNA. Type I procollagen protein was evaluated by immunochemistry. Viability of biopsies in culture using 3H-uridine incorporation into RNA was observed to be > 80% for at least 96 hours. Following addition of either IL-10 or triamcinolone acetonide there was a modest but significant decrease (P < 0.05) in type I procollagen mRNA expression. Similarly, each agent added individually to biopsies reduced the proportion of cells staining positively for type I procollagen when compared to biopsies treated with medium alone (P < 0.05). These results extend in vitro data that IL-10 and corticosteroids down-regulate collagen synthesis in skin fibroblast cell lines and suggest that this ex vivo model may offer a closer approximation to the post-operative scarring process when testing new therapeutic agents for reducing an over-exuberent fibrotic response.

Double blind placebo controlled trial of nebulised budesonide for croup

AIMS

To determine whether nebulised budesonide improves the symptoms or shortens the duration of stay of children admitted to hospital with a clinical diagnosis of croup.

METHODS

A prospective, randomised, double blind placebo controlled trial. Patients received either nebulised budesonide or placebo every 12 hours. The main outcome measures were duration of inpatient stay and croup scores at 30 minutes, one, two, four, 12, and 24 hours.

RESULTS

87 patients (89 admissions) aged 7-116 months entered the trial. Nebulised budesonide was associated with a significant improvement in symptoms at 12 hours (95% confidence interval (CI) 1 to 3) and 24 hours (95% CI 0 to 3). Patients with an initial croup score above 3 demonstrated a significant improvement in symptoms at two hours (95% CI 1 to 3). Nebulised budesonide was also associated with a 33% reduction in the length of stay (95% CI 2% to 63%) when the confounding variables of age, initial croup score, and coryzal symptoms were taken into consideration.

CONCLUSIONS

Nebulised budesonide is an effective treatment for children admitted to hospital with a clinical diagnosis of croup.

[Effects of topical corticosteroids on subepithelial haze after excimer laser corneal surgery--objective and quantitative method for evaluating haze]

To examine the effectiveness of topical corticosteroids in decreasing subepithelial haze induced by excimer laser keratectomy, we performed excimer laser keratectomy on 24 eyes of 12 albino rabbits using a scanning excimer laser system (EC-5000, NIDEK, Japan). Topical dexamethasone 0.1% was applied topically to 8 corneas after surgery (steroid group), but not to the others (control group). Slit-lamp biomicroscopic examination and objective measurement of scattered light from subepithelial haze were performed before and 2, 4, 8 and 12 weeks after surgery, the rabbits were killed after 2 or 12 weeks and the eyes were examined histologically. In both groups, densitometric values of scattered light intensity increased up to 4 weeks after surgery, and then decreased gradually. However, the values of the steroid group were larger than those of the control group at all stages, and the values of the steroid group at 12 weeks after surgery were similar to preoperative values. There was statistically significant difference in scattered light intensity between the two groups (p < 0.005). Two weeks after surgery, the corneas of the control group showed epithelial hyperplasia and a remarkable increase in activated keratocytes and subepithelial fibrous tissues. However, in the steroid group these light microscopic findings could not be observed. At 12 weeks after surgery, the corneas of the control group retained a small amount of activated keratocytes and fibrous tissues, and those of the steroid group were normal. This study suggests that a short course of topical corticosteroids may be very effective in decreasing subepithelial haze after excimer laser corneal surgery.

Asthma therapy with aerosols: clinical relevance for the next decade

Inhaled therapy is the mainstay of modern asthma management, as this optimizes the therapeutic ratio. Short-acting beta 2-agonists are the most effective bronchodilators and when given by inhalation give rapid relief of symptoms, without adverse effects, although there are concerns about overuse of these drugs. Inhaled long-acting beta 2-agonists are useful in some patients. Inhaled anticholinergics are particularly useful in patients with COPD and in the future long-acting drugs, such as tiotropium bromide, will be available. Inhaled glucocorticoids are the most effective therapy in controlling chronic asthma symptoms, and systemic effects are not a problem in the vast majority of patients. Improved inhalation devices and steroids with reduced oral bioavailability have resulted in reduced systemic side effects, which now arise largely from absorption from the lungs. In the future it is likely that new classes of drug will be developed, but whether they will be used by inhalation or given by mouth will depend on the frequency of side effects and the mode of action of the drugs. There are likely to be several improvements in inhaler delivery systems, so that the inhaled route will remain predominant for many years to come.

Effect of glucocorticoids on neonatal rabbit renal cortical sodium-inorganic phosphate messenger RNA and protein abundance

Administration of glucocorticoids to neonates increases proximal tubule volume absorption by increasing glucose, bicarbonate, and amino acid transport. We have recently demonstrated that glucocorticoids may contribute to the maturational decrease in phosphate transport. This study examines the maturation of NaPi-6 [the regulated proximal tubule sodium-inorganic phosphate (Na-Pi) transporter] mRNA and protein abundance and the mechanism for the decrease in phosphate transport by glucocorticoids. Weaned young rabbits (5 wk) had a 2-fold greater brush border membrane NaPi-6 protein abundance than that measured in adults. Renal cortical NaPi-6 mRNA abundance was comparable in neonates (less than 10 d of age) and adults. Renal brush border membrane vesicles from dexamethasone-treated neonatal rabbits (10 micrograms/100 g of body weight for 4 d) had a lower rate of Na-Pi transport than vehicle-treated controls (46.8 +/- 6.5 versus 71.0 +/- 9.0 pmol 32P/10 s/mg of protein, p < 0.05). Abundance of NaPi-6 protein in brush border membrane vesicles was 3-fold lower in newborn rabbits treated with pharmacologic doses of dexamethasone than in vehicle-treated controls. NaPi-6 mRNA abundance was the same in both groups. NaPi-1, a brush border membrane phosphate transporter which is also an anion channel, mRNA, and protein abundance was not affected by glucocorticoids. These data demonstrate that there is a maturational decrease in NaPi-6 protein abundance and that glucocorticoids decrease neonatal phosphate transport, at least in part, by reducing the number of Na-Pi transporters.

Clinical use of dexamethasone for termination of unwanted pregnancy in dogs

Dexamethasone was administered orally for 7.5 or 9.5 days to 80 pregnant bitches to terminate unwanted pregnancy at an outpatient clinic. Treatment was initiated at day 30-35 (n = 74) or day 45-50 (n = 6) of confirmed pregnancy using one of two dosages. In 62 bitches, dexamethasone was administered twice a day for 7.5 days increasing from 0.1 to 0.2 mg kg-1 over the first 2 days of administration and decreasing from 0.16 to 0.02 mg kg-1 over the last five administrations. The 18 remaining bitches were given dexamethasone twice a day for 9.5 days, at a dosage of 0.2 mg kg-1 for 7 days and then decreasing from 0.16 to 0.02 mg kg-1 over the last five administrations. Pregnancy was terminated without complication in 75 of the 80 bitches, and uterine contents were absorbed or aborted or both. Pregnancy was not terminated in five bitches treated for 7.5 days beginning at day 30-35 of gestation. In four of them parturition occurred at the normal time; in one, pregnancy was terminated by a second treatment. Pregnancy termination occurred at 7-15 days after the start of treatment. During ultrasonographic imaging of 13 bitches treated with dexamethasone, fetal deaths occurred between 5 and 13 days after the start of treatment. The side effects reported by the owners included polydipsia and polyuria, which were observed in all of the bitches and which disappeared when the treatment was discontinued. Some bitches also experienced vaginal discharge, restlessness, anorexia or emesis. At the first or second cycle after treatment, 20 bitches were mated and had normal pregnancies and normal litters. The results suggest that oral treatment with dexamethasone can be used to terminate pregnancy in bitches, but that in some cases the withdrawal of treatment after 8 days can result in retention of live pups and require a further treatment or the use of another abortifacient.

Efficacy of topical retinoic acid compared with topical fluocinolone acetonide in the treatment of oral lichen planus

The purpose of this study was to compare the efficacy of retinoic acid in an oral base 0.05% with fluocinolone acetonide in an oral base 0.1% in the treatment of atrophic and erosive oral lichen planus. Thirty-three patients with histologically proven oral lichen planus were asked to participate in the study. Lesions were scored ranging from 0 (no lesion) to 5 (large erosion) according to the severity. Patients were randomly assigned to receive either topical fluocinolone acetonide or topical retinoic acid. They were instructed to apply the medication on dried lesions four times a day. The lesions were evaluated after 2 and 4 weeks of treatment. The sign scores were analyzed by the Wilcoxon rank sum test. Eighteen patients receiving topical fluocinolone acetonide improved from the average score of 3.0 to 1.5 after 4 weeks of treatment, whereas 15 patients receiving topical retinoic acid showed little change (average score, 2.9 and 2.4, respectively). The changes were statistically significantly different between the two groups (p = 0.01). The results suggest that 0.1% fluocinolone acetonide reduced the severity of atrophic and erosive oral lichen planus better than 0.05% retinoic acid.

Preadipocyte recruitment in stromal vascular cultures after depletion of committed preadipocytes by immunocytotoxicity

Glucocorticoids or the glucocorticoid analog dexamethasone (DEX) enhances the differentiation of preadipocytes in the presence of insulin and influences preadipocyte proliferation. The purpose of the present study was to determine if DEX can induce the recruitment of preadipocytes. Using monoclonal antibodies for complement-mediated cytotoxicity, preadipocytes were removed from porcine stromal vascular (S-V) cell cultures. Our experiments demonstrated for the first time that after removal of preadipocytes by cytotoxicity, preadipocytes or fat cells could be induced by DEX or DEX plus insulin but not by insulin alone. However, many more fat cells were induced (258 +/- 15/unit area) when DEX was added with fetal bovine serum (FBS) followed with insulin treatment, compared to DEX with insulin (21.3 +/- 5.1/ unit area) after removal of preadipocytes. Immunocytochemistry with AD-3, a preadipocyte marker, showed that DEX with FBS for 3 days after seeding (i.e., the proliferation phase) produced many more preadipocytes (AD-3 positive, 223 +/- 45/unit area) than FBS alone (10.5 +/- 1.4/unit area). Bromodeoxyuridine (BrdU) incorporation assays demonstrated that the efficiency of DEX with FBS (i.e., during proliferation) was mitosis dependent. Accordingly, we conclude that: porcine S-V cultures contain preadipocytes at different stages of differentiation; and that DEX induced early preadipocyte differentiation depends on mitosis.

Diagnosis and management of iris juvenile xanthogranuloma

BACKGROUND

Juvenile xanthogranuloma is a benign, self-limiting cutaneous disorder most commonly encountered during infancy. Approximately 10% of cases may develop ocular or adnexal involvement, most commonly in the iris.

METHODS

We review clinical and morphological features of four cases of iris juvenile xanthogranuloma that reflect the diagnostic and therapeutic spectrum.

RESULTS

Tissue diagnosis was confirmed in all cases; in one case, the disease was diagnosed with a skin biopsy and treated with local and systemic steroids, and its persistence in the iris was confirmed with a second tissue specimen obtained five months after systemic steroid treatment.

CONCLUSION

The diagnosis and treatment of juvenile xanthogranuloma may be straightforward, particularly in cases when the ocular lesion receives early attention and responds well to topical steroids, and when there is no hyphema. However, in other instances, this entity may be difficult to manage and may necessitate iris biopsy for diagnosis and radiation therapy for treatment.

Kaposi's sarcoma during immunosuppressive therapy for atopic dermatitis

We describe an HIV-negative homosexual man who developed Kaposi's sarcoma (KS). He had CD4 lymphocytopenia during azathioprine and topical corticosteroid therapy for atopic dermatitits (AD). KS was observed after only 2 months of immunosuppressive therapy. No regression was observed despite discontinuation of immunosuppressive therapy and normalization of the CD4+ cell count. This patient appears to be the first case of KS associated with AD. Moreover, as our patient had been sexually inactive for 15 years, this case raises the questions about the latency and about the sexual transmission of a novel herpes-like virus (KHSHV) recently detected in all forms of KS.

The mechanism of altered neural function in a rat model of acute colitis

BACKGROUND & AIMS

Distal colitis induced in rats by trinitrobenzene sulfonic acid (TNBS) causes a suppression of [3H]noradrenaline release from the myenteric plexus, of inflamed distal colon, as well as in noninflamed regions of colon and ileum. The aim of this study was to explore the mechanisms underlying these neural changes in TNBS colitis.

METHODS

Colitis was induced by intrarectal administration of TNBS, and the animals were killed on day 5. Inflammation was assessed by measuring myeloperoxidase (MPO) activity, and noradrenaline release was measured as 3H release from rats myenteric plexus preparations preloaded with [3H]noradrenaline. These end points were examined: (1) after administration of the locally active steroid budesonide; (2) in congenitally athymic rats; and (3) in rats treated with the interleukin 1 receptor antagonist (IL-1ra) to interleukin 1 beta.

RESULTS

In colitis, both topical budesonide and systemic IL-1ra treatments attenuated the suppression of KCl-evoked 3H release from longitudinal muscle myenteric plexus in both inflamed and noninflamed segments. However, neither of these treatments altered MPO activity. A similar suppression of [3H]noradrenaline release was observed in athymic rats after TNBS, although there was a substantially greater increase in MPO activity compared with euthymic rats with colitis.

CONCLUSIONS

TNBS-induced colitis alters myenteric nerve function at inflamed and noninflamed sites via a steroid-sensitive and interleukin 1-mediated process that does not require T lymphocytes.

Does ketotifen have a steroid-sparing effect in childhood asthma?

In view of the possible systemic side-effects of inhaled corticosteroids (ICS), a study was performed to determine whether ketotifen (versus placebo) can replace or allow a reduction in the dose of ICS required for the maintenance treatment of childhood asthma. Sixty six children (aged 6-13 yrs) with asthma (confirmed by methacholine challenge), who were maintained on ICS, at a dose of < or = 1 mg.day-1, were selected, and 52 subjects completed the trial. Children on long-term oral steroids or cromoglycate were excluded. After a 4 week baseline period, the children were randomized to receive ketotifen, 2 mg.day-1, or placebo for 32 Weeks. Between weeks 13-20 of the study, the daily dose of steroid was tapered by 25% every second week to the minimum dose tolerated by the patients. For the remainder of the study (Weeks 21-32) the patients continued on this dose (if tolerated). Beta 2-agonists were allowed, as necessary, for symptom relief. During the baseline period, the mean daily ICS dosage was 432 micrograms in the ketotifen group versus 408 micrograms in the placebo group (NS). Among the-patients who completed the study, the average ICS dosage during the final phase of the study (Weeks 21-32) was only 18% of baseline in the ketotifen group versus 35% in the placebo group (NS). Lung function, diurnal variability in peak flow rates and methacholine sensitivity (provocative concentration producing a 20% fall in forced expiratory volume in one second (PC20)) remained unchanged in both groups throughout the study. During the last 12 weeks of the study, the ketotifen-treated patients were symptomatically better controlled. In the present study, ketotifen did not have a greater steroid-sparing effect than placebo.

[The application of corticosteroid following photorefractive keratectomy]

OBJECTIVE

The application methods of corticosteroid following excimer laser photorefractive keratectomy (PRK) were compared.

METHODS

PRK was performed on 600 myopic eyes with Nidek-EC 5000 PRK System, and then randomly they were divided into group A (228 eyes) and B (372 eyes). Different methods of application of corticosteroid were performed in the two groups. The follow-up period was 6 months.

RESULTS

After 6 months of follow-up, the rate of uncorrected visual acuity > or = 0.8 or > or = 1.0 was 97.9%, 93.2% in group A and 98.6%, 93.5% in group B, respectively. Transient ocular hypertension occurred in 2.2% in group A and 2.7% in group B, but the difference was statistically not significant (P > 0.05), the rate of haze greater than grade 1 was 18.4% in group A and 5.4% in group B, with statistically significant difference (P < 0.05).

CONCLUSION

After PRK, the appropriate application of corticosteriod can effectively reduce the rate of haze formation and regression towards myopia caused by haze. Powerful corticosteroid used at postoperative early stage and its low concentration at later stage can reduce the incidence of corticosteroid ocular hypertension.