Progesterone receptor isoform expression in response to in utero growth restriction in the fetal guinea pig brain.

Intra-uterine growth restriction (IUGR) is a significant in utero complication that can have profound effects on brain development including reduced myelination and deficits that can continue into adulthood. Progesterone increases oligodendrocyte proliferation and myelin expression, an action that may depend on the expression of progesterone receptor (PR) isoforms A (PRA) and B (PRB). The objective of this study was to determine the effect of IUGR on PR isoform expression in the brain of male and female fetuses and whether effects were associated with a reduction in myelination. We used a guinea pig model that involves selective reduction in maternal perfusion to the placenta at midgestation (35 days, term 70 days). This resulted in a significant reduction in body weight with marked sparing of brain weight. PRA, PRB and myelin basic protein (MBP) expression were measured in the brains of male and female growth-restricted and control fetuses at late gestation. MBP, as a measure of myelination, was found to decrease in association with IUGR in the CA1 hippocampal region with no change observed in the cortical white matter. There was a marked increase in PRA, PRB and total PR expression in the IUGR fetal brain. Control female fetuses demonstrated significantly higher PRA:PRB ratios than males; however, this sex difference was abolished with IUGR. These data suggest the central nervous system effects of clinical use of progesterone augmentation therapy in late pregnancy should be carefully evaluated. The overall upregulation of PR isoforms in association with IUGR suggests increased progesterone action and a possible neuroprotective mechanism.

TGF-ß upregulates CD70 expression and induces exhaustion of effector memory T cells in B-cell non-Hodgkin's lymphoma.

Transforming growth factor beta (TGF-ß) has an important role in mediating T-cell suppression in B-cell non-Hodgkin lymphoma (NHL). However, the underlying mechanism responsible for TGF-ß-mediated inhibition of effector memory T (Tm) cells is largely unknown. As reported here, we show that exhaustion is a major mechanism by which TGF-ß inhibits Tm cells, and TGF-ß mediated exhaustion is associated with upregulation of CD70. We found that TGF-ß upregulates CD70 expression on effector Tm cells while it preferentially induces Foxp3 expression in naive T cells. CD70 induction by TGF-ß is Smad3-dependent and involves IL-2/Stat5 signaling. CD70+ T cells account for TGF-ß-induced exhaustion of effector Tm cells. Both TGF-ß-induced and preexisting intratumoral CD70+ effector Tm cells from B-cell NHL have an exhausted phenotype and express higher levels of PD-1 and TIM-3 compared with CD70- T cells. Signaling transduction, proliferation and cytokine production are profoundly decreased in these cells, and they are highly susceptible to apoptosis. Clinically, intratumoral CD70-expressing T cells are prevalent in follicular B-cell lymphoma (FL) biopsy specimens, and increased numbers of intratumoral CD70+ T cells correlate with an inferior patient outcome. These findings confirm TGF-ß-mediated effector Tm cell exhaustion as an important mechanism of immune suppression in B-cell NHL.

The effect of betamethasone treatment on neuroactive steroid synthesis in a foetal Guinea pig model of growth restriction.

There are ongoing concerns that antenatal corticosteroids, which are administered to women at high risk of delivering preterm to reduce the incidence of respiratory distress syndrome, have adverse effects on foetal brain development and subsequent effects on behaviour and learning, when administered as repeated courses. The present study aimed to examine whether repeated betamethasone treatment alters the expression of the key-rate limiting enzyme, 5alpha-reductase, in the synthetic pathway of the potent neuroactive steroid allopregnanolone in the brain and placenta and whether this effect is potentiated in growth restricted foetuses. To investigate this, pregnant guinea pigs carrying either control (sham surgery) or growth-restricted foetuses were treated with vehicle or betamethasone (1 mg/kg/day) for 4 days prior to sacrifice (65d). Placental insufficiency was induced by the ablation of uterine artery branches supplying each placenta at mid gestation, resulting in foetal growth restriction characterised by 'brain sparing'. Real-time reverse transcriptase polymerase chain reaction was used to determine relative 5alpha-reductase type 1 and 2 mRNA expression in the placenta and brain. Immunohistochemistry was used to examine the glial fibrillary acidic protein (GFAP) expression in the subcortical white matter, CA1 and dentate regions of the hippocampus. 5alpha-reductase type 2 mRNA expression in the brain was markedly reduced by betamethasone treatment in male foetuses compared to vehicle-treated controls but not in female foetuses. In addition, 5alpha-reductase type 1 expression in the brain was increased by growth restriction and/or betamethasone treatment in female foetuses but expression in males foetuses did not increase. 5alpha-reductase type 2 expression in the placenta was markedly reduced by betamethasone treatment compared to vehicle-treated control. Intrauterine growth restriction and betamethasone treatment reduced GFAP expression in the CA1 region of the hippocampus in the brains of male but not female foetuses. These data indicate that betamethasone treatment suppresses placental expression and has sexually dimorphic effects on expression of neuroactive steroid synthetic enzymes in the brain. These actions may lead to adverse effects on the developing brain, particularly in male foetuses, such as the observed effects on GFAP expression.

Regular inhaled beta-agonist treatment in bronchial asthma.

89 subjects with stable asthma took part in a double-blind, placebo-controlled, randomized, crossover study of the effects of regular versus on-demand inhaled bronchodilator therapy. The subjects inhaled fenoterol or placebo by a dry powder delivery system for 24 weeks. Control of asthma was judged by daily morning and evening peak expiratory flow rates, symptom diaries, use of additional inhaled bronchodilator, and requirement for short courses of prednisone. Of 64 subjects who completed the trial, 57 showed a clear difference in degree of control of asthma between the fenoterol and placebo periods: in 17 (30% [95% confidence interval 18.4-43.4%]) asthma was better controlled during regular inhaled bronchodilator treatment, whereas in 40 (70% [56.6-81.6%]) control was better during placebo treatment with bronchodilator for symptom relief only. Mean airway responsiveness to methacholine increased slightly during the fenoterol period. The adverse effect of regular bronchodilator inhalation occurred not only among subjects who used a bronchodilator as sole treatment (2 were better and 10 were worse during regular bronchodilator treatment) but also among those who took inhaled corticosteroids (14 were better and 29 were worse). Thus, regular inhalation of a beta-sympathomimetic agent was associated with deterioration of asthma control in the majority of subjects. The trends to use of regular, higher doses or longer-acting inhaled beta-sympathomimetic treatment may be an important causal factor in the worldwide increase in morbidity from asthma.

Regular inhaled beta agonist in asthma: effects on exacerbations and lung function.

BACKGROUND: A comparison of the effects of regular upsilon as needed inhaled beta agonist treatment on the control of asthma in the last 16 weeks of each of two 24 week treatment periods has been reported. This paper presents additional information on exacerbations of asthma and trends in lung function, airways hyperresponsiveness to methacholine, and bronchodilator responsiveness during the entire 24 week periods of regular or as needed beta agonist treatment. METHODS: Subjects undertook a year long randomised, double blind crossover study of regular upsilon as needed inhaled beta agonist treatment. Fenoterol (400 micrograms) or matching placebo was inhaled as a dry powder four times daily for 24 weeks, then subjects crossed over to the alternative regimen. Treatment with inhaled corticosteroids was used by 50 of the 64 subjects in constant doses throughout the study. Symptoms, peak expiratory flow rates, and drug use were recorded daily, spirometry was performed every four weeks, and methacholine and bronchodilator responsiveness were measured every eight weeks. RESULTS: Exacerbations of asthma symptoms occurred earlier and more often during regular treatment with fenoterol and four of five severe exacerbations requiring admission to hospital occurred during the period of regular treatment. Prebronchodilator forced expiratory volume in one second (FEV1) was on average 0.15 litres lower (95% confidence interval (95% CI) 0.11-0.19) and vital capacity (VC) 0.12 litres lower (95% CI 0.08-0.16) than during the placebo period. Morning peak flow rates were significantly lower and evening peak flow rates significantly higher, with an increase in diurnal variation from 9.8% (95% CI 6.9-12.8) to 17.5% (95% CI 13.8-21.3) during regular treatment. Geometric mean concentration of methacholine causing a 20% fall in FEV1 from the value after saline (PC20) decreased significantly from 1.63 to 1.15 mg/ml, indicating increased bronchial hyperresponsiveness during regular treatment. Response to bronchodilator, as measured by the % increase in postbronchodilator FEV1 related to prebronchodilator FEV1, was maintained with no evidence for tachyphylaxis. CONCLUSION: Chronic use of inhaled fenoterol resulted in more exacerbations, a significant decline in baseline lung function, and an increase in airway responsiveness to methacholine in asthmatic subjects, but did not alter bronchodilator responsiveness. These findings support the previous report that regular inhaled beta agonist treatment is deleterious in the long term control of asthma.