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PubMed2005

Effectiveness of oral dexamethasone in the treatment of moderate to severe pharyngitis in children.

OBJECTIVE: To determine the effectiveness of a single dose of oral dexamethasone in reducing the pain associated with moderate to severe pharyngitis in pediatric patients. DESIGN: Prospective, randomized, double-blind, placebo-controlled clinical trial. SETTING: Large, urban pediatric emergency department between March 2002 and November 2003. PATIENTS: Children aged 5 to 18 years with moderate to severe pharyngitis (odynophagia or dysphagia, moderate to severe pharyngeal erythema or swelling, and a McGrath Facial Affective Scale score of 0.75 or higher [scale 0.0-1.0]). INTERVENTIONS: Study patients were randomly assigned to receive 1 dose of either oral dexamethasone suspension (0.6 mg/kg with a maximum of 10 mg) or placebo of the same volume. All participants were tested for group A beta-hemolytic streptococcal pharyngitis and treated accordingly. Daily telephone follow-up was conducted until complete resolution of sore throat. MAIN OUTCOME MEASURES: Primary outcome variables included hours to initial relief of sore throat and time to the complete resolution of pain. Secondary outcome variables included changes in the McGrath Facial Affective Scale score at 24 and 48 hours, persistence of associated symptoms, use of anti-inflammatory or antipyretic medication, and subsequent use of medical resources for dehydration or pain. RESULTS: A convenience sample of 150 patients was randomized to receive either dexamethasone (n = 75) or placebo (n = 75). Twenty-five patients were lost to follow-up, leaving 125 patients available for data analysis; 57 received dexamethasone and 68 received placebo. Patients who received dexamethasone reported earlier onset of pain relief (9.2 vs 18.2 hours; P<.001), fewer hours to complete resolution of sore throat (30.3 vs 43.8 hours; P = .04), and larger changes in the McGrath Facial Affective Scale score in the first 24 hours (-0.58 vs -0.43; P = .002). Children who tested negative for group A beta-hemolytic streptococci had greater pain relief with dexamethasone compared with placebo (onset of pain relief, 8.7 vs 24 hours; P = .001), less time to complete resolution of sore throat (37.9 vs 70.8 hours; P = .006), and greater changes in the McGrath Facial Affective Scale score in the first 24 hours (-0.50 vs -0.21; P<.001). CONCLUSION: Children with moderate to severe pharyngitis had earlier onset of pain relief and shorter duration of sore throat when given oral dexamethasone.

Administration, Oral↗

PubMed1993

The effect of antenatal dexamethasone administration on the fetal and neonatal ductus arteriosus. A randomized double-blind study.

OBJECTIVE: To determine whether antenatal dexamethasone sodium phosphate administration constricts the fetal ductus arteriosus or improves spontaneous closure of the ductus in premature infants. DESIGN: A randomized double-blind study. SETTING: University hospital of Helsinki, Finland. PARTICIPANTS: Sixty-one pregnant women with threatened preterm delivery between 24 and 31.9 weeks' gestation and 57 of their offspring (28 in the dexamethasone and 29 in the placebo group), born at 24 to 34.9 weeks' gestation, were studied using Doppler echocardiography. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Between the dexamethasone and placebo groups, there were no significant differences in systolic or diastolic flow velocity values in the fetal ductus arteriosus. Of the 29 infants with respiratory distress syndrome, 26 (90%) had hemodynamically significant patent ductus arteriosus and received indomethacin sodium: 12 (92%) of 13 dexamethasone-treated infants and 14 (88%) of 16 placebo-treated infants. One placebo-treated infant was ligated. Of the 28 infants without respiratory distress syndrome, only four (14%) had hemodynamically significant patent ductus arteriosus. In infants born at or before 30 weeks' gestation, spontaneous closure of the ductus occurred more frequently after administration of prenatal dexamethasone (in six of 17 infants; 35%) than placebo (in none of 10 infants; P < .05). CONCLUSIONS: Our data indicate that antenatal dexamethasone administration had no constrictive effect on the ductus arteriosus of the fetus between 24 and 31 weeks' gestation. However, antenatal dexamethasone had a beneficial effect on ductal closure in very premature infants.

Adult↗

PubMed1993

Follow-up of preterm infants treated with dexamethasone for chronic lung disease.

OBJECTIVE: To study the outcome of prolonged treatment with dexamethasone sodium phosphate in preterm infants who depend on assisted ventilation. DESIGN: Longitudinal follow-up using historic controls. SETTING: Regional intensive care nursery. PARTICIPANTS: Sixty-one very-low-birth-weight infants treated with a 42-day course of dexamethasone and 61 historic controls matched for birth weight, gestational age, race, and sex. All 122 subjects required assisted ventilation for at least 15 days. INTERVENTION: Infants were given dexamethasone sodium phosphate at a dose of 0.5 mg/kg per day. The dose was then tapered over 42 days. MEASUREMENTS/MAIN RESULTS: Infants treated with dexamethasone received assisted ventilation for a median of 33 days; controls, a median of 47 days (P < .05). One hundred infants survived; 94 were examined at age 1 year. The two groups were similar with respect to the proportions hospitalized for respiratory infection in the first year of life and the proportions with weight, length, and head circumference below the fifth percentile. Rates of cerebral palsy were also similar between the two groups, as were median Bayley Mental and Psychomotor developmental index scores. CONCLUSIONS: Dexamethasone treatment was associated with fewer days of assisted ventilation, but not with improved outcome at age 1 year. More assessment should be made of dexamethasone's effect on long-term outcome before dexamethasone becomes widely used in preterm infants who depend on assisted ventilation.

Chronic Disease↗

PubMed1999

Prevention of chronic lung disease in preterm infants by early postnatal dexamethasone therapy.

Recent studies suggest that early dexamethasone therapy may lessen the pulmonary inflammation in preterm infants with respiratory distress syndrome (RDS). To investigate whether early (<12 hr) postnatal dexamethasone therapy would reduce the incidence of chronic lung disease (CLD), a randomized, double-blind, controlled trial was conducted in 40 infants (birth weights from 500 to 1,999 gm) who had severe RDS and required mechanical ventilation within 6 hr of birth. All infants received one dose of Survanta before they were randomly assigned to control (saline placebo) or dexamethasone-treated groups (0.5 mg/kg/d for 1 week, then tapered over 3 weeks). Sequential analysis was performed with the end point of assessment being the presence or absence of CLD on postnatal Day 28. Statistical significance favoring dexamethasone was reached when 12 consecutive pairs in which one infant had CLD and the other did not have CLD showed that ten pairs favored dexamethasone and two pairs favored control treatment. Among the survivors, 12/15 were extubated in the dexamethasone group and 9/16 in the control group at the end of study. Infants in the treated group had transient hyperglycemia and hypertension. There was no difference between the groups in mortality and in incidence of sepsis or intraventricular hemorrhage. We conclude that early postnatal dexamethasone therapy is potentially effective in the lessening of CLD in preterm infants. To substantiate our result, large randomized controlled trials are needed and warranted.

Anti-Inflammatory Agents↗

PubMed1985

Improved control of cisplatin-induced emesis with high-dose metoclopramide and with combinations of metoclopramide, dexamethasone, and diphenhydramine. Results of consecutive trials in 255 patients.

A series of consecutive trials were undertaken to determine whether higher doses of intravenous metoclopramide and combinations of metoclopramide, dexamethasone, and diphenhydramine would improve antiemetic control or decrease treatment-related side effects in patients receiving cisplatin at 120 mg/m2. Metoclopramide and dexamethasone were studied because of their proven efficacy as single agents and their differing mechanisms of action and side effects. Diphenhydramine was used because of its possible antiemetic properties and its ability to control acute dystonic reactions. Two hundred fifty-five patients who had never received chemotherapy or antiemetics were observed in the hospital for the 24 hours following cisplatin administration. The addition of dexamethasone or dexamethasone plus diphenhydramine to intravenous metoclopramide 2 mg/kg produced both improved antiemetic control and a decrease in treatment-associated diarrhea (P = 0.002). The use of metoclopramide alone at a dose of 3 mg/kg for only two doses appeared as effective as 2 mg/kg for five doses. When dexamethasone and diphenhydramine were given with metoclopramide 3 mg/kg for two intravenous dosages, 81% of patients experienced no emesis and 93% had two or fewer vomiting episodes. The antiemetic results of this 2-hour "short-course" regimen were superior to metoclopramide 2 mg/kg, with (P = 0.002) or without (P = 0.0001) dexamethasone and diphenhydramine. It was concluded that combinations of metoclopramide plus dexamethasone plus diphenhydramine improve antiemetic control, facilitate the usage of higher doses of metoclopramide, and decrease the incidence of treatment-related side effects.

Adult↗

PubMed1992

A randomized trial of intrahepatic infusion of fluorodeoxyuridine with dexamethasone versus fluorodeoxyuridine alone in the treatment of metastatic colorectal cancer.

To decrease the toxicity of hepatic arterial fluorodeoxyuridine (FUDR) administered through an Infusaid pump (Shiley Infusaid, Inc., Norwood, MA), 50 patients with liver metastases from colorectal cancer were selected randomly to receive FUDR, 0.3 mg/kg/d, for 14 of 28 days, with or without a total dose of 20 mg of hepatic arterial dexamethasone for 14 of 28 days. Patients were stratified according to the percentage of liver involvement by tumor and the perfusion pattern on macroaggrated albumin perfusion scan (MAA) scan. There was a trend toward decreased frequency of bilirubin levels in the group receiving dexamethasone plus FUDR versus the group receiving FUDR alone (9% and 30%, respectively, had a 200% or greater increase from baseline; P = 0.07). Patients in the group treated with dexamethasone and FUDR received higher doses of FUDR in the second, third, fifth, and sixth months than those receiving FUDR alone; however, this was statistically significant only in the fifth month (percentages of planned dose received: 42% and 19%, respectively; P = 0.05), and there was no overall difference for the total 6-month period. The complete and partial response rates were increased in patients receiving dexamethasone and FUDR versus FUDR alone (8% and 63% versus 4% and 36%, respectively; P = 0.03), and there was a trend toward increased survival with the addition of dexamethasone (median, 23 months and 15 months, respectively; P = 0.06). In conclusion, the use of hepatic arterial dexamethasone is associated with an increased response rate and a trend toward increased survival and decreased bilirubin levels. Therefore, the authors recommend additional investigation of the use of dexamethasone with chemotherapy to treat hepatic metastases.

Adult↗

PubMed2000

Sulfur mustard toxicity in macrophages: effect of dexamethasone.

Cells from the murine macrophage-like cell line J774A.1 (J774) and cultures of primary alveolar macrophages (PAM) obtained from guinea pigs were exposed to sulfur mustard (HD, 50-200 microM) and treated with dexamethasone (2.5 microM) 10 min after HD exposure. Cell cultures were studied at 3 and 24 h after exposure by the cleavage of Thiazolyl blue reaction (MTT) reaction and crystal violet staining (viability assays), by morphological observation and by [3H]thymidine incorporation. Exposure of J774 cells to HD caused a dose-dependent decrease in viability that was evident at 24 h. Although no significant change in viability was observed at 3-4 h after HD exposure, a dose-dependent decrease in [3H]thymidine incorporation was observed. Treatment with dexamethasone caused a dose-dependent decrease in viability. However, the combined exposure to HD and dexamethasone had a synergistic effect on the decrease of cell viability. This synergistic effect is not due to a change in DNA synthesis rate because [3H]thymidine incorporation was not affected by dexamethasone. In PAM cultures, HD caused some 'activating' effect on [3H]thymidine incorporation and an increase in cell number at the lower dose (100 microM) but this was less at 200 microM. Both effects were reduced by dexamethasone treatment. We conclude that macrophages derived from different sources exhibit a different responsiveness to immunomodulators (HD and dexamethasone) and that dexamethasone can reduce the 'inflammatory' effect of HD in PAM.

Animals↗

PubMed1986

Dexamethasone induces proliferation and terminal differentiation of osteogenic cells in tissue culture.

Dexamethasone is an important regulator of cellular proliferation and differentiation, but paradoxical effects have been noted in a variety of culture systems. The purpose of this study was to determine whether dexamethasone induces proliferation and differentiation of osteogenic precursor cells. Periosteal explants from embryonic chicks were grown in culture for 3 or 4 days, treated continuously with dexamethasone or ethanol vehicle, and then either pulse-labeled with 3H-thymidine at 3 days or labeled for 24 hr between day 3 and day 4. Histochemical and autoradiographic procedures were used to assess the proliferation and differentiation of osteogenic cells. At 3 days, the area of bone, the percentage of alkaline phosphatase-positive cells, the percentage of 3H-thymidine-labeled cells, and the percentage of cells labeled with both markers were significantly higher in dexamethasone-treated cultures. Between day 3 and day 4 no significant changes in these parameters were observed in the dexamethasone-treated cultures. In comparison, control cultures exhibited significant increases in the percentage of 3H-thymidine-labeled cells after 24 hr of continuous labeling. The data show that dexamethasone induces a burst of proliferation in a cohort of cells that undergo differentiation. Once these cells have divided, further proliferation within the culture is limited. Finally, it is apparent that the timing of experiments may be critical in determining whether dexamethasone will inhibit or stimulate proliferation.

Alkaline Phosphatase↗

PubMed2005

Flow perfusion culture induces the osteoblastic differentiation of marrow stroma cell-scaffold constructs in the absence of dexamethasone.

Flow perfusion culture of scaffold/cell constructs has been shown to enhance the osteoblastic differentiation of rat bone marrow stroma cells (MSCs) over static culture in the presence of osteogenic supplements including dexamethasone. Although dexamethasone is known to be a powerful induction agent of osteoblast differentiation in MSC, we hypothesied that the mechanical shear force caused by fluid flow in a flow perfusion bioreactor would be sufficient to induce osteoblast differentiation in the absence of dexamethasone. In this study, we examined the ability of MSCs seeded on titanium fiber mesh scaffolds to differentiate into osteoblasts in a flow perfusion bioreactor in both the presence and absence of dexamethasone. Scaffold/cell constructs were cultured for 8 or 16 days and osteoblastic differentiation was determined by analyzing the constructs for cellularity, alkaline phosphatase activity, and calcium content as well as media samples for osteopontin. For scaffold/cell constructs cultured under flow perfusion, there was greater scaffold cellularity, alkaline phosphatase activity, osteopontin secretion, and calcium deposition compared with static controls, even in the absence of dexamethasone. When dexamethasone was present in the cell culture medium under flow perfusion conditions, there was further enhancement of osteogenic differentiation as evidenced by lower scaffold cellularity, greater osteopontin secretion, and greater calcium deposition. These results suggest that flow perfusion culture alone induces osteogenic differentiation of rat MSCs and that there is a synergistic effect of enhanced osteogenic differentiation when both dexamethasone and flow perfusion culture are used.

Animals↗

PubMed2005

Prolonged duration local anesthesia with lipid-protein-sugar particles containing bupivacaine and dexamethasone.

Glucocorticoids prolong block duration from polymeric microspheres containing bupivacaine, but not from unencapsulated drug. Here we investigate this effect applies to particles with much more rapid drug release and improved long-term biocompatibility. Male Sprague-Dawley rats were given sciatic nerve blocks with 75 mg of 3% or 60% (w/w) dipalmitoylphosphatidylcholine (DPPC) spray-dried lipid-protein-sugar particles (LPSPs) containing 10% (w/w) bupivacaine and 0%, 0.05%, or 0.1% (w/w) dexamethasone. Sensory nerve block from bupivacaine-containing 3% and 60% (w/w) DPPC particles without dexamethasone yielded blocks lasting 301 +/- 56 and 321 +/- 127 min, respectively. Addition of 0.05% (w/w) dexamethasone increased block durations to 610 +/- 182 and 538 +/- 222 min, respectively; increasing dexamethasone loading to 0.1% did not further increase duration. One day after injection, dexamethasone-containing particles resulted in lower inflammation scores and capsule thickness than dexamethasone-free particles, but the difference was gone by day 4. Excipient composition had prominent effects at all time points. For all groups, inflammation was largely resolved by 2 weeks after injection. Dexamethasone approximately doubled the duration of nerve block from bupivacaine-loaded LPSPs, while maintaining excellent biocompatibility. Such formulations could be useful in clinical applications when nerve blockade is needed for 24 hours or less.

Anesthesia, Local↗

PubMed2006

Dexamethasone-functionalized gels induce osteogenic differentiation of encapsulated hMSCs.

Synthetic hydrogels represent highly controlled environments for three-dimensional culture of human mesenchymal stem cells (hMSCs). Encapsulated hMSCs are presented with a "blank" environment, and this environment can be closely controlled in order to elicit an osteogenic response. In vitro, dexamethasone is an efficient and reliable factor that leads to the osteogenic differentiation of human mesenchymal stem cells (hMSCs). The aim of this work was to develop a dexamethasone-releasing poly(ethylene glycol) (PEG)-based hydrogel scaffold to deliver dexamethasone to encapsulated cells in a sustained manner. To accomplish this goal, dexamethasone was covalently linked to a photoreactive mono-acrylated PEG molecule through a degradable lactide bond, and this molecule was covalently incorporated into the PEG hydrogel during photopolymerization. Over time, hydrolysis of the ester bonds resulted in dexamethasone release from the gel. The biological activity of the released dexamethasone was verified in monolayer cell culture and in three-dimensional culture (i.e., in the gel) by the ability of hMSCs to express osteogenic genes, including alkaline phosphatase, osteopontin, and core binding factor alpha 1, as measured using real-time reverse transcription polymerase chain reaction (RT-PCR). These studies indicate that encapsulated hMSCs are capable of osteogenic differentiation in response to released dexamethasone.

Alkaline Phosphatase↗

PubMed1993

Expression of annexin I, II, V, and VI by rat osteoblasts in primary culture: stimulation of annexin I expression by dexamethasone.

To determine whether rat osteoblasts synthesize proteins of the annexin family and to evaluate the extent to which glucocorticoids modulate the expression of annexins by these cells, osteoblasts were grown in primary cultures in the absence or presence of dexamethasone, and the expression of annexins was evaluated by immunoblotting using polyclonal antibodies against human annexins. Four different annexins (I, II, V, and VI) were found to be expressed by rat osteoblasts. The expression of annexin I, but not the other annexins studied, was increased in osteoblasts cultured in the presence of dexamethasone (173 +/- 33% increase comparing untreated cells and cells treated for 10 days with 5 x 10(-7) M dexamethasone). Increased expression of annexin I was observed after the third day of exposure to dexamethasone and rose thereafter until day 10; annexin I expression increased with dexamethasone concentrations above 10(-10) M throughout the range of concentrations studied. The increase in annexin I protein was associated with an increase in annexin I mRNA and was completely blocked by the concomitant addition of the glucocorticoid receptor antagonist RU 38486. The increase in annexin I content following dexamethasone treatment was associated with an increase in alkaline phosphatase activity and PTH-induced cAMP stimulation, whereas phospholipase A2 activity in the culture medium was reduced to undetectable levels. The finding that four annexins are expressed in rat osteoblasts in primary culture raises the possibility that these proteins could play an important role in bone formation by virtue of their ability to bind calcium and phospholipids, serve as Ca2+ channels, interact with cytoskeletal elements, and/or regulate phospholipase A2 activity. In addition, the dexamethasone-induced increase in annexin I may represent a mechanism by which glucocorticoids modify osteoblast function.

Alkaline Phosphatase↗

PubMed2003

Effect of dexamethasone withdrawal on osteoblastic differentiation of bone marrow stromal cells.

Dexamethasone is capable of directing osteoblastic differentiation of bone marrow stromal cells (BMSCs) in vitro, but its effects are not lineage-specific, and sustained exposure has been shown to down-regulate collagen synthesis and induce maturation of an adipocyte subpopulation within BMSC cultures. Such side effects might be reduced if dexamethasone is applied in a regimented manner, but the discrete steps in osteoblastic maturation that are stimulated by dexamethasone are not known. To examine this, dexamethasone was added to medium to initiate differentiation of rat BMSCs cultures and then removed after a varying number of days. Cell layers were analyzed for cell number, rate of collagen synthesis, expression of osteocalcin (OC), bone sialoprotein (BSP) and lipoprotein lipase (LpL), and matrix mineralization. Withdrawal of dexamethasone at 3 and 10 days was found to enhance cell number relative to continuous exposure, but did not affect to decrease collagen synthesis slightly. Late markers of osteoblastic differentiation, BSP expression and matrix mineralization, were also sensitive to dexamethasone and increased systematically with exposure while LpL systematically decreased. These results indicate that dexamethasone acts at both early and late stages to direct proliferative osteoprogenitor cells toward terminal maturation.

Animals↗

PubMed1991

Dexamethasone and retinoic acid regulate the expression of epidermal growth factor receptor mRNA by distinct mechanisms.

Retinoic acid and dexamethasone have antagonistic effects on epidermal growth factor (EGF) receptor expression in fetal rat lung (FRL) cells: Receptor synthesis is enhanced by retinoic acid and reduced by dexamethasone. In the presence of actinomycin D, neither agent has the capacity to modify receptor synthesis or 125I-EGF binding capacity. Northern blot analysis demonstrates a tenfold increase in EGF mRNA following retinoic acid treatment and a 60% decrease in receptor message levels after dexamethasone treatment. To dissect the mechanisms of these effects, the expression of mRNA was separated from effects requiring protein synthesis by the use of cycloheximide and actinomycin D. Ligand binding, EGF receptor protein synthesis, and mRNA levels were measured in cultures of FRL cells that were incubated with retinoic acid or dexamethasone in the presence of cycloheximide, then washed and reincubated with fresh media containing actinomycin D, but not retinoic acid, dexamethasone, or cycloheximide. The results demonstrate that dexamethasone reduces the expression of EGF receptor mRNA in the absence of protein synthesis. In contrast, the mechanism by which retinoic acid increases the expression of EGF receptor mRNA requires protein synthesis. These data indicate that, in FRL cells, dexamethasone negatively regulates EGF receptor mRNA in a direct manner, while retinoic acid controls transcription of an intermediate protein, possibly a transcription factor, that subsequently increases transcription of receptor message.

Animals↗

PubMed1989

Characteristics of monocyte angiotensin-converting enzyme (ACE) induction by dexamethasone.

Monocyte maturation to macrophages and transformation into epithelioid granuloma cells in some granulomatous diseases are accompanied by the induction of membrane-bound angiotensin-converting enzyme (ACE). The physiologic and pathophysiologic roles of ACE generated in these processes are not known. The pattern and the mechanism of ACE induction in human monocytes are also not well understood. Dexamethasone is one of the agents reported to induce elevated ACE activity in human monocytes, and therefore a suitable tool for studying the phenomenon. This study shows that dexamethasone augments monocyte ACE in a biphasic dose-dependent manner with maximum effect at 10(-8) M concentration. Although it enhances the level of ACE activity, dexamethasone does not alter the time course for ACE induction from that found in unstimulated monocytes. The ACE activity of monocytes cultivated in 10 nM dexamethasone and then exposed to 10(-3) M diazosulfanilic acid (DASA) is reduced approximately by 80% in comparison with cells not treated with DASA, demonstrating that dexamethasone-induced ACE is an ectoenzyme. Dexamethasone does not increase the activity of other monocyte ectoenzymes: gamma-glutamyltransferase, alkaline phosphodiesterase-I, and leucine aminopeptidase, showing that dexamethasone induction of ACE is a specific, rather than generalized, effect on plasma membrane enzymes. It is suggested that the increase in ACE activity is due to the increased rate of enzyme synthesis.

Dexamethasone↗

PubMed1999

Dexamethasone inhibits dendritic cell maturation by redirecting differentiation of a subset of cells.

To investigate how corticosteroids affect differentiation of human dendritic cells (DC) in a defined inflammatory environment, we incubated immature DC with dexamethasone in the presence of tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), and prostaglandin E2. Dexamethasone inhibited differentiation into mature DC, as indicated by the reduced expression of antigen-presenting molecules, costimulatory and adhesion molecules, a marker of mature DC, and IL-12. Dexamethasone increased expression of CD14, CD36, and CD68, molecules characteristic of monocytes/macrophages and induced CD14+CD83- cells, a subset distinct both from immature DC and mature DC. The effects were concentration-dependent, with ID50 values between 2 and 30 nM dexamethasone. Unlike T and B cells, in DC dexamethasone induced no apoptosis, although it suppressed activated nuclear transcription factor NF-kappaB. Dexamethasone reduced the ability of DC to stimulate proliferation of allogeneic T cells in proportion to the level of CD14+CD83- cells in the population. CD83+ cells, isolated from dexamethasone-treated populations, retained the synthesis of IL-12 and the ability to stimulate proliferation of allogeneic T cells. Our data demonstrate that the dominant effect of the drug was redirecting differentiation of a subset of cells despite the presence of inflammatory cytokines. The observed ID50 values indicate that inhibition of DC differentiation might contribute significantly to in vivo immunosuppression by chronic administration of corticosteroids.

Antigen Presentation↗

PubMed1993

Dexamethasone treatment suppresses collagen synthesis in infants with bronchopulmonary dysplasia.

Collagen is an essential component of connective tissue and is present in the pulmonary interstitium. Collagen deposition is known to increase in many acquired chronic diseases, including bronchopulmonary dysplasia (BPD). Urinary excretion of hydroxyproline has been used as a specific index of collagen synthesis. Many studies have demonstrated that dexamethasone therapy is associated with respiratory improvement in infants with BDP but the mechanism of this effect is not well understood. We postulated that in infants with BDP who receive dexamethasone, suppression of collagen synthesis may cause respiratory improvement. Therefore, we studied the effect of dexamethasone on respiratory status and urinary excretion of hydroxyproline in 14 ventilator-dependent infants with BDP. Infants received 0.5 mg/kg/day dexamethasone, tapered by half every 3 days to complete a 12 day course. Eleven of the 14 infants were extubated at a mean +/- SD of 8.7 +/- 4.9 days after starting dexamethasone. Mean urinary hydroxyproline/creatinine ratios at 3, 6, 9, and 12 days of dexamethasone therapy were significantly lower than the mean pretreatment value, but after discontinuation rapidly rose toward baseline values. Decreased urinary excretion of hydroxyproline indicates that dexamethasone suppressed collagen synthesis in these infants. We speculate that suppression of collagen synthesis reduced pulmonary inflammation and fibrosis, resulting in respiratory improvement.

Bronchopulmonary Dysplasia↗

PubMed1996

The combination of endotoxin and dexamethasone induces type II interleukin 1 receptor (IL-1r II) in monocytes: a comparison to interleukin 1 beta (IL-1 beta) and interleukin 1 receptor antagonist (IL-1ra).

Soluble type II interleukin 1 receptor (IL-1r II) and interleukin 1 receptor antagonist (IL-1ra) regulate inflammation by competitively inhibiting the binding of IL-1 beta to the signalling IL-1 receptor. In addition, glucocorticoids also regulate IL-1 beta by suppressing gene transcription. More recently, glucocorticoids have been shown to increase soluble IL-1r II concentrations, which may contribute to their anti-inflammatory properties. Interestingly, increased serum levels of soluble IL-1r II and IL-1ra have been measured in septic patients, although the mechanism is unclear. In this respect, the authors characterize new pathways in which IL-1r II and IL-1ra may be regulated in sepsis through combined stimulation with lipopolysaccharide (LPS) and dexamethasone of peripheral blood mononuclear cells (PBMC). This paper confirms that while dexamethasone induces release of IL-1r II, LPS augments dexamethasone-induced IL-1r II release 45-fold. Furthermore, LPS plus dexamethasone induces IL-1r II protein and mRNA, whereas LPS alone does not. Additionally, it was shown by flow cytometric analysis that the monocyte is the primary IL-1r II producer in response to LPS and dexamethasone administration. Therefore, LPS and dexamethasone synergism in IL-1r II induction may be important in controlling IL-1 beta effects. In contrast, LPS alone induces IL-1ra, while dexamethasone attenuates this LPS-induced response. Although IL-1r II and IL-1ra may work together to suppress IL-1 beta effects in sepsis, inflammatory cells differentially regulate these cytokines.

Blotting, Western↗