Some effects of exogenous hydrocortisone on pregnancy in the rat

PPAR-γ Modulators as Current and Potential Cancer Treatments

Worldwide, cancer has become one of the leading causes of mortality. Peroxisome Proliferator-Activated Receptors (PPARs) is a family of critical sensors of lipids as well as regulators of diverse metabolic pathways. They are also equipped with the capability to promote eNOS activation, regulate immunity and inflammation response. Aside from the established properties, emerging discoveries are also made in PPAR's functions in the cancer field. All considerations are given, there exists great potential in PPAR modulators which may hold in the management of cancers. In particular, PPAR-γ, the most expressed subtype in adipose tissues with two isoforms of different tissue distribution, has been proven to be able to inhibit cell proliferation, induce cell cycle termination and apoptosis of multiple cancer cells, promote intercellular adhesion, and cripple the inflamed state of tumor microenvironment, both on transcriptional and protein level. However, despite the multi-functionalities, the safety of PPAR-γ modulators is still of clinical concern in terms of dosage, drug interactions, cancer types and stages, etc. This review aims to consolidate the functions of PPAR-γ, the current and potential applications of PPAR-γ modulators, and the challenges in applying PPAR-γ modulators to cancer treatment, in both laboratory and clinical settings. We sincerely hope to provide a comprehensive perspective on the prospect of PPAR-γ applicability in the field of cancer treatment.

Maternal and fetal outcomes in pregnancies with long-term corticosteroid use

PURPOSE

Long-term corticosteroids are administered in pregnant patients with an array of autoimmune and inflammatory disorders. Our objective is to determine whether long-term corticosteroid use is associated with increased maternal and neonatal adverse outcomes.

MATERIALS AND METHODS

We performed a retrospective cohort study using the Healthcare Cost and Utilization Project-national Inpatient Sample from the USA. All pregnant patients on long-term corticosteroids were identified using International Classification of Disease-9 coding from 2003 to 2015. The effect of long-term corticosteroid use on maternal and neonatal outcomes was evaluated using multivariate logistic regression.

RESULTS

Out of the 10,491,798 births included in our study, 3999 were among women with long-term use of steroids, for an overall prevalence of 38 per 100,000 births. There was a steady increase in chronic steroid use from 2 to 81 per 100,000 births over the 13-year study period (p < .0001). Women on long-term steroids were more likely to have pregnancies complicated by preeclampsia, 1.72 (1.30-2.29) and were at greater risk of preterm premature rupture of membranes, 1.63 (1.01-2.44), pyelonephritis, 4.81 (1.18-19.61), and venous thromboembolisms, 2.50 (1.32-4.73). Neonates born from mothers on long-term steroids were more likely to suffer from prematurity, 1.51 (1.13-2.05), and lower weight for gestational age, 2.10 (1.34-3.30).

CONCLUSION

Long-term corticosteroids use in pregnancy is associated with maternal and fetal adverse outcomes. These patients would benefit from close follow-up throughout their pregnancy to minimize complications.

Teratology - past, present and future

Teratology is the science that studies the causes, mechanisms, and patterns of abnormal development. The authors present an updated overview of the most important milestones and stages of the development of modern teratology. Development of knowledge and society led to the recognition that causes of congenital developmental disorders (CDDs) might be caused by various mechanical effects, foetal diseases, and retarded or arrested development of the embryo and foetus. Based on the analysis of the historical development of hypotheses and theories representing a decisive contribution to this field, we present a survey of the six Wilson's fundamental principles of teratology. The aim of observing these principles is to get insight into developmental relations and to understand mechanisms of action on the level of cell populations (elementary morphogenetic processes), tissues and organs. It is important to realise that any negative intervention into the normal course of these processes, either on genetic or non-genetic basis, inevitably leads to a sequence of subsequent changes resulting in CDDs. Moreover, the classical toxicologic monotonic dose-response paradigm recently has been challenged by the so-called "low dose-hypothesis", particularly in the case of endocrine active substances. These include some pesticides, dioxins, polychlorobiphenyls (PCBs), and bisphenol A. Despite modern approaches of molecular biology and genetics, along with top diagnostic techniques, we are still not able to identify the actual cause in more than 65 to 70% of all congenital defects classified as having an unknown etiology. Today CDDs include any birth defect, either morphological, biochemical, or behavioural.

Prenatal dexamethasone exposure induces changes in nonhuman primate offspring cardiometabolic and hypothalamic-pituitary-adrenal axis function

Prenatal stress or glucocorticoid administration has persisting "programming" effects on offspring in rodents and other model species. Multiple doses of glucocorticoids are in widespread use in obstetric practice. To examine the clinical relevance of glucocorticoid programming, we gave 50, 120, or 200 microg/kg/d of dexamethasone (dex50, dex120, or dex200) orally from mid-term to a singleton-bearing nonhuman primate, Chlorocebus aethiops (African vervet). Dexamethasone dose-dependently reduced maternal cortisol levels without effecting maternal blood pressure, glucose, electrolytes, or weight gain. Birth weight was unaffected by any dexamethasone dose, although postnatal growth was attenuated after dex120 and dex200. At 8 months of age, dex120 and dex200 offspring showed impaired glucose tolerance and hyperinsulinemia, with reduced (approximately 25%) pancreatic beta cell number at 12 months. Dex120 and dex200 offspring had increased systolic and diastolic blood pressures at 12 months. Mild stress produced an exaggerated cortisol response in dex200 offspring, implying hypothalamic-pituitary-adrenal axis programming. The data are compatible with the extrapolation of the glucocorticoid programming hypothesis to primates and indicate that repeated glucocorticoid therapy and perhaps chronic stress in humans may have long-term effects.

Glucocorticoid "Programming" and PTSD Risk

Epidemiological data have linked an adverse fetal environment with increased risks of cardiovascular, metabolic, neuroendocrine, and psychiatric disorders in adulthood. Prenatal stress and/or glucocorticoid excess might underlie this link. In animal models, prenatal stress, glucocorticoid exposure or inhibition/knockout of 11 beta-hydroxysteroid dehydrogenase type 2 (11 beta-HSD-2), the feto-placental barrier to maternal glucocorticoids, reduces birth weight and causes permanent hypertension, hyperglycemia, increased hypothalamic-pituitary-adrenal (HPA) axis activity and behavior resembling of anxiety. In humans, 11 beta-HSD-2 gene mutations cause low birth weight and placental 11 beta-HSD-2 activity correlates directly with birth weight and inversely with infant blood pressure. Low birth weight babies have higher plasma cortisol levels throughout adult life, indicating HPA programming. In human pregnancy, severe maternal stress affects the offspring HPA axis and associates with neuropsychiatric disorders. Posttraumatic stress disorder (PTSD) appears to be a variable in the effects. Intriguingly, some of these effects appear to be 'inherited' into a further generation, itself unexposed to exogenous glucocorticoids at any point in the lifespan from fertilization, implying epigenetic marks persist into subsequent generation(s). Overall, the data suggest that prenatal exposure to excess glucocorticoids programs peripheral and CNS functions in adult life, predisposing to some pathologies, perhaps protecting from others, and these may be transmitted perhaps to one or two subsequent generations.

Glucocorticoid programming

Epidemiological evidence suggests that an adverse fetal environment permanently programs physiology, leading to increased risks of cardiovascular, metabolic, and neuroendocrine disorders in adulthood. Prenatal glucocorticoid excess or stress might link fetal maturation and adult pathophysiology. In a variety of animal models, prenatal glucocorticoid exposure or inhibition of 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2), the fetoplacental "barrier" to maternal glucocorticoids, reduces birth weight and causes permanent hypertension, hyperglycemia, and increased hypothalamic-pituitary-adrenal axis (HPA) activity and behavior resembling anxiety. In humans, 11beta-HSD2 gene mutations cause low birth weight and reduced placental 11beta-HSD2 activity associated with intrauterine growth retardation. Low birth weight babies have higher plasma cortisol levels throughout adult life, indicating HPA programming. The molecular mechanisms may reflect permanent changes in the expression of specific transcription factors; key is the glucocorticoid receptor itself. Differential programming of the glucocorticoid receptor in different tissues reflects effects upon one or more of the multiple tissue-specific alternate first exons/promoters of the glucocorticoid receptor gene. Overall, the data suggest that either pharmacological or physiological exposure to excess glucocorticoids prenatally programs pathologies in adult life.

Sexually dimorphic effects of maternal alcohol intake and adrenalectomy on left ventricular hypertrophy in rat offspring

In humans, low birth weight and increased placental weight can be associated with cardiovascular disease in adulthood. Low birth weight and increased placental size are known to occur after fetal alcohol exposure or prenatal glucocorticoid administration. Thus the effects of removing the alcohol-induced increase in maternal corticosterone by maternal adrenalectomy on predictors of cardiovascular disease in adulthood were examined in rats. Alcohol exposure of dams during the last 2 wk of gestation resulted in significantly decreased fetal weight and increased placental weight on gestational day 21. Adult female, but not male, offspring of alcohol-consuming mothers exhibited left ventricular hypertrophy. Placental 11beta-hydroxysteroid dehydrogenase-2 (11beta-HSD-2) mRNA levels, measured by Northern blot, were decreased in females but not males. Adrenalectomy of alcohol-consuming dams reversed the increase in placental weight and the decrease in female placental 11beta-HSD-2 expression and eliminated the left ventricular hypertrophy of adult female offspring. These data suggest that alcohol-induced changes in placental 11beta-HSD-2 mRNA levels and left ventricular weight are coupled in female offspring only and depend on maternal adrenal status.

Glucocorticoid programming of the fetus; adult phenotypes and molecular mechanisms

It has been long recognised that the glucocorticoid administration to pregnant mammals (including humans) reduces offspring birth weight. Epidemiologically, low weight or thinness at birth is associated with an increased risk of cardiovascular and metabolic disorders in adult life. So, does fetal exposure to glucocorticoids produce such 'programming' of adult disorders? Here data are reviewed which show, in rodents and other model species, that antenatal exposure to glucocorticoids reduces offspring birth weight and produces permanent hypertension, hyperglycaemia, hyperinsulinaemia, altered behaviour and neuroendocrine responses throughout the lifespan. This occurs with exogenous (dexamethasone) or endogenous glucocorticoids, the latter achieved by inhibiting 11 beta-hydroxysteroid dehydrogenase type 2, the feto-placental enzymic barrier to maternal glucocorticoids. Processes underlying fetal programming include determination of the 'set point' of the hypothalamic-pituitary-adrenal axis and of tissue glucocorticoid receptor expression. Detailed molecular mechanisms are being dissected. Analogous stress axis hyperreactivity occurs in lower birth weight humans and may be an early manifestation and indicate approaches to manipulation or prevention of the phenotype.

Glucocorticoids, feto-placental 11 beta-hydroxysteroid dehydrogenase type 2, and the early life origins of adult disease

Increasing human epidemiological data suggest that events that subtly retard intrauterine growth may determine common disorders, such as hypertension and non-insulin-dependent diabetes, in adult life. The underlying mechanisms are unknown. However, excessive fetal exposure to glucocorticoids retards growth and "programs" adult hypertension in rats. 11 beta-Hydroxysteroid dehydrogenase type 2 (11 beta-HSD2) catalyzes the rapid inactivation of cortisol and corticosterone to inert 11 keto-products. Normally, 11 beta-HSD2 in the placenta and some fetal tissues is thought to protect the fetus from excess maternal glucocorticoids. In both rats and humans there is considerable natural variation in placental 11 beta-HSD2, and enzyme activity correlates with birth weight. Moreover, inhibition of feto-placental 11 beta-HSD2 in the rat reduces birth weight and produces hypertensive and hyperglycaemic adult offspring, many months after prenatal treatment; effects are dependent upon intact maternal adrenals, suggesting a direct action on the fetus or placenta. Maternal protein restriction during pregnancy also produces hypertensive offspring and selectively attenuates placental 11 beta-HSD2 activity. These data suggest that feto-placental 11 beta-HSD2, by regulating fetal exposure to maternal glucocorticoids, crucially determines fetal growth and the programming of later disorders. Deficiency of the barrier to maternal glucocorticoids may represent a common pathway between the maternal environment and feto-placental programming of later disease. These data may, at least in part, explain the human observations linking early life events to the risk of subsequent disease.

11 beta-Hydroxysteroid dehydrogenases: key enzymes in determining tissue-specific glucocorticoid effects

Recent studies have demonstrated that the interconversion of active and inactive glucocorticoids plays a key role in determining the specificity of the mineralocorticoid receptor and controlling local tissue glucocorticoid receptor activation. Two distinct isoforms of the enzyme 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) have been identified. 11 beta-HSD1 is NADPH-dependent and at its major site of action (the liver) is a reductase, converting cortisone to cortisol (11-dehydrocorticosterone to corticosterone in the rat). 11 beta-HSD2 is NAD-dependent, is present in tissues such as the kidney and placenta, and converts cortisol to cortisone (corticosterone to 11-dehydrocorticosterone in the rat). Congenital or acquired deficiency of 11 beta-HSD2 produces the syndrome of apparent mineralocorticoid excess (SAME) in which cortisol gains access to the unprotected nonspecific mineralocorticoid receptor. The congenital deficiency is associated with mutations in the gene encoding the kidney isoform of 11 beta-HSD2; the acquired form results from inhibition of the enzyme by licorice, carbenoxolone, ACTH-dependent steroids in the ectopic ACTH syndrome, and possibly circulating inhibitors of the enzyme. This paper focuses on recent evidence, which suggest that low levels of placental 11 beta-HSD2 result in increased exposure of the fetus to maternal glucocorticoid and low birth weight. In animal studies using the rat we have shown that birth weight is correlated positively and placental weight negatively with the level of placental 11 beta-HSD. Thus animals with low birth weight and large placentae were those likely to be exposed to the highest level of maternal glucocorticoid. In man a similar relationship was found with birth weight being significantly correlated either with placental 11 beta-HSD activity or with the extent of cortisol inactivation by isolated perfused placental cotyledons. Administration of dexamethasone (which is poorly metabolized by placental 11 beta-HSD2) to pregnant rats resulted in decreased birth weight and the development of hypertension in the pups when adult. The same results were obtained when pregnant rats were given carbenoxolone, an inhibitor of placental 11 beta-HSD2. Low protein diet during pregnancy in the rat resulted in low birth weight of the pups, increased placental weight but decreased placental 11 beta-HSD activity, and adult hypertension. Thus increased glucocorticoid exposure of the fetus secondary to a failure of the normal inactivation of maternal glucocorticoid by the placental may be an important mechanism linking changes in the in utero environment and common adult diseases.

Placental 11 beta-hydroxysteroid dehydrogenase and the programming of hypertension

Excessive foetal exposure to glucocorticoids retards growth and "programmes" adult hypertension in rats. Placental 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD), which catalyses the conversion of corticosterone and cortisol to inert 11 keto-products, normally protects the foetus from excess maternal glucocorticoids. In both rats and humans there is considerable natural variation in placental 11 beta-HSD, and enzyme activity correlates with birth weight. Moreover, inhibition of placental 11 beta-HSD in the rat reduces birth weight and produces hypertensive adult offspring, many months after prenatal treatment with enzyme inhibitors; these effects are dependent upon maternal adrenal products. These data suggest that placental 11 beta-HSD, by regulating foetal exposure to maternal glucocorticoids, crucially determines foeto-placental growth and the programming of hypertension. Maternal protein restriction during pregnancy also produces hypertensive offspring and selectively attenuates placental 11 beta-HSD activity. Thus, deficiency of the placental barrier to maternal glucocorticoids may represent a common pathway between the maternal environment and foeto-placental programming of later disease. These data may, at least in part, explain the human epidemiological observations linking early life events to the risk of subsequent hypertension. The recent characterization, purification and cDNA cloning of a distinct human placental 11 beta-HSD (type 2) will aid the further study of these intriguing findings.

Comparison of dexamethasone-induced embryotoxicity in vitro in mouse and rat embryos

Previous work demonstrated that rat embryos were more susceptible to the growth retardation effect of the synthetic glucocorticoid dexamethasone (DEX) in vivo than were mouse embryos. The purpose of this study was to examine this species difference using an in vitro system. Embryos of CD rats and CD-1 mice were cultured in a whole embryo culture system with concentrations of DEX from 5 to 250 micrograms/ml. Rat embryos were explanted on day 9 of gestation (GD 9: plug day = GD 0), while mouse embryos were removed on GD 8. After 48 h in culture, each viable embryo was evaluated for morphological score, and the number of somite pairs, crown-rump, and head lengths, as well as DNA and protein concentrations were determined. A reduced morphological score was observed for mouse embryos at 5 micrograms DEX/ml, but a significant decrease in this parameter was only observed at DEX concentrations of > or = 100 micrograms/ml in rat embryos. Significant reductions in the number of somite pairs were observed at 25 micrograms/ml for mouse embryos and 100 micrograms/ml for rat embryos. Crown-rump and head lengths as well as DNA and protein concentrations were significantly decreased at 100 micrograms/ml in mouse embryos and 150 micrograms/ml in rat embryos. Therefore, in vitro mouse embryos were adversely affected by lower concentrations of DEX than were rat embryos for each of the six end points examined in this study. This species sensitivity in vitro could be due to inherent genetic differences or to the slightly different developmental stages evaluated using the culture system.(ABSTRACT TRUNCATED AT 250 WORDS)

11 beta-hydroxysteroid dehydrogenase isoforms and their implications for blood pressure regulation

11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) catalyzes the reversible conversion of physiological glucocorticoids (cortisol, corticosterone) to inactive products. The enzyme thus protects non-selective renal mineralocorticoid receptors from circulating glucocorticoids (ensuring aldosterone-selectivity in vivo), excludes maternal glucocorticoids from the foetal circulation and modulates glucocorticoid access to glucocorticoid receptors in other tissues. 11 beta-HSD has been purified from rat liver, antisera raised, a cDNA isolated and its human homologue cloned. However, it is difficult to reconcile all of the actions of 11 beta-HSD with a single enzyme. Here data are reviewed that demonstrate not only molecular heterogeneity of the 'liver-type' 11 beta-HSD, but also the existence of a novel high affinity isoform in the placenta and perhaps distal nephron. These data are discussed in the light of their potential physiological and pathological importance, with particular reference to the pathogenesis of hypertension.

Placental toxicity in rats after administration of synthetic glucocorticoids. A morphological, histochemical and immunohistochemical investigation

Administration of the synthetic glucocorticoids dexamethasone and triamcinolone to pregnant rats between gestational day (GD) 16 and 20 caused dose-dependent placental lesions on GD 21 and 22 which were detected by morphological, histochemical and immunohistochemical means. Maternal blood spaces, trophoblast layer and fetal blood vessels were altered primarily in the centre of the placental labyrinth. Less severe changes were found in the junctional zone, chorionic plate and intraplacental yolk sac. On GD 21, low doses increased the amount of glycogen, while high doses induced a loss of glycogen. gamma-glutamyl transpeptidase activity was increased in the spongiotrophoblast and the labyrinthic trophoblast and dipeptidyl peptidase IV activity in fetal capillary endothelium, whereas alpha-glutamyl aminopeptidase and microsomal alanyl amino-peptidase were not affected. Additionally, in the fetal capillary endothelium an increase of immunoreactivity for the von Willebrand factor occurred. These data suggest that synthetic glucocorticoids affect placental tissues at different and rather specific levels, which may in turn disturb placental function and contribute to fetal maldevelopment.

Comparative distribution and metabolism of triamcinolone acetonide and cortisol in the rat embryomaternal unit

Triamcinolone acetonide (TAC) is teratogenic in rats while cortisol has been reported as not teratogenic. The objective of this investigation was to determine whether this difference in teratogenicity could be due to a difference in the metabolism and distribution of the parent compound in the embryomaternal unit. 3H-TAC and 14C-cortisol were administered intramuscularly to pregnant rats on day 12 of gestation. These dams were killed at each of the following time points after injection: 0.5, 1, 3, 6 and 24 hr. Maternal plasma and embryos were analyzed by high performance liquid chromatography (HPLC) and liquid scintillation counting. The plasma concentration of parent TAC was significantly greater than that for parent cortisol at all time points. The plasma elimination half-life for TAC, 86 min, was also calculated to be significantly longer than that for cortisol, 8 min. Furthermore, the percentage of total plasma radioactivity representing HPLC resolved TAC was much higher than that representing cortisol at all time points. The concentration of TAC in the embryos was significantly greater than for cortisol at all time points. The elimination half-life for unchanged TAC in the embryos was 142 min compared to 22 min for cortisol. The percentage of total radioactivity in the embryos representing unchanged TAC was similar to that found in maternal plasma while the percentage of total radioactivity representing unchanged cortisol was much lower than that found in maternal plasma. These findings support the hypothesis that differences in the distribution and metabolism of the parent compound are a critical factor in determining the teratogenicity of that compound.

Teratogenic effects of cyproterone acetate and medroxyprogesterone treatment during the pre- and postimplantation period of mouse embryos. I

Pregnant mice were treated with a single subcutaneous injection of either cyproterone acetate (CA) or medroxyprogesterone acetate (MPA). In the first experiment the animals received 5-900 mg/kg of the hormone before implantation (day 2 of pregnancy). CA treatment on day 2 caused a dose-dependent decrease in fetal weight and a significant dose-dependent increase in the rates of cleft palate and urinary tract abnormalities. Exencephaly and heart abnormalities were also significantly more frequent, but this increase was not dose-dependent. MPA treatment on day 2 was followed by sporadic increases in dead and resorbed fetuses, a decrease in fetal weight and an increase in the rates of cleft palate, and malformed or abnormally developed fetuses. None of these effects, however, was dose-dependent. In the second experiment the mice were given one single injection (30 mg/kg) of CA or MPA on any one of days 1-12 of gestation. Treatment with CA on one day between days 1 and 12 revealed that the specific sensitivity for abnormalities of the urinary tract was on days 5 and 6, for the respiratory tract on days 8 and 9, and for cleft palate on days 10 and 11. Treatment with MPA on one day between days 1 and 12 only revealed a high rate of respiratory and urinary tract abnormalities on day 9. After treatment with MPA cleft palate was again significantly more frequent in all treated groups, however, days of peak sensitivity were not detected. The long half-life of CA (60 hours) explains the teratogenic effect of high doses of this progestin after treatment on day 2 and also the pattern of abnormal development found after treatment with a single dose of CA on one of the days between day 1 and day 12.

Teratogenesis: a review of the basic principles with a discussion of selected agents: Part III

Before a woman realizes she is pregnant, a large amount of development has occurred in the embryo. If she consumes a drug during her pregnancy, the possibility exists that the drug could harm the fetus. The most important variable is timing, with the fetus showing the highest degree of susceptibility during the first trimester of gestation.

This article presents data on the relative time a pregnancy test becomes positive as compared to fetal development; passage of drugs across the placenta; placental and fetal drug metabolism; and the availability of teratogenic information to health professionals. Teratogenic effects of specific substances or classes of substances are discussed, including alcohol, analgesics, antibiotics, anticoagulants, anticonvulsants, antithyroid/thyroid drugs, various environmental agents, and paternal drug exposure.