Heat treatment enhances the antimicrobial activity of (+)-Catechin when combined with copper sulphate.

UNLABELLED: The aim of the study was to compare the antimicrobial activities of freshly made, heat-treated (HT) and 14 day stored (+)-Catechin solutions with (+)-catechin flavanol isomers in the presence of copper sulphate. (+)-Catechin activity was investigated when combined with different ratios of Cu(2+) ; 100°C heat treatment; autoclaving; and 14 day storage against Staphylococcus aureus. Cu(2+) -(+)-Catechin complexation, isomer structure-activity relationships, and H2 O2 generation were also investigated. Freshly made, HT, and 14 day stored flavanols showed no activity. While combined Cu(2+) -autoclaved (+)-Catechin and -HT(+)-Catechin activities were similar, HT(+)-Catechin was more active than either freshly made (+)-catechin (generating more H2 O2 ) or (-)-Epicatechin (though it generated less H2 O2 ) or 14 day-(+)-Catechin (which had similar activity to Cu(2+) controls-although it generated more H2 O2 ). When combined with Cu(2+) , in terms of rates of activity, HT(+)-Catechin was lower than (-)-Epigallocatechin gallate and greater than freshly made (+)-Catechin. Freshly made and HT(+)-Catechin formed acidic complexes with Cu(2+) as indicated by pH and UV-vis measurements although pH changes did not account for antimicrobial activity. Freshly made and HT(+)-Catechin both formed Cu(2+) complexes. The HT(+)-Catechin complex generated more H2 O2 which could explain its higher antimicrobial activity. SIGNIFICANCE AND IMPACT OF THE STUDY: Natural products attract considerable attention in the search for novel antimicrobials, prebiotics and antioxidants. Enhanced biological activity of natural products has been demonstrated with chemical and heat treatment. This article extends the few publications on heat treatments of plant products and combinations with adjuncts, to raise antimicrobial activity against pathogens such as Staphylococcus aureus. We demonstrated that heat treatment could increase the activity of (+)-Catechin, a weak antimicrobial flavanol found commonly in plants in the presence of copper sulphate. Heat treatment of readily available resources merits consideration in the development of more potent substances for use in clinical settings and agriculture.

Characterization of the adverse effects of nicotine on placental development: in vivo and in vitro studies.

In utero exposure to nicotine is associated with increased risk of numerous adverse fetal and neonatal outcomes, which suggests that it acts directly to affect placental development and the establishment of the fetomaternal circulation (FC). This study used both in vivo [Wistar rats treated with 1 mg/kg nicotine from 2 wk prior to mating until gestational day (GD) 15] and in vitro (RCHO-1 cell line; treated with 10(-9) to 10(-3)M nicotine) models to examine the effects of nicotine on these pathways. At GD 15, control and treated placentas were examined for the impact of nicotine on 1) trophoblast invasion, proliferation, and degree of hypoxia, 2) labyrinth vascularization, 3) expression of key genes of placental development, and 4) expression of placental angiogenic factors. The RCHO-1 cell line was used to determine the direct effects of nicotine on trophoblast differentiation. Our in vivo experiments show that nicotine inhibits trophoblast interstitial invasion, increases placental hypoxia, downregulates labyrinth vascularization as well as key transcription factors Hand1 and GCM1, and decreases local and circulating EG-VEGF, a key placental angiogenic factor. The in vitro experiments confirmed the inhibitory effects of nicotine on the trophoblast migration, invasion, and differentiation processes and demonstrated that those effects are most likely due to a dysregulation in the expression of nicotine receptors and a decrease in MMP9 activity. Taken together, these data suggest that adverse effects of maternal smoking on pregnancy outcome are due in part to direct and endocrine effects of nicotine on the main processes of placental development and establishment of FC.

Interleukin-15 treatment improves glucose homeostasis and insulin sensitivity in obese mice.

The prevalence of metabolic diseases associated with obesity, such as type 2 diabetes, continues to rise along with obesity rates. Recently, obesity has been described as an inflammatory condition, suggesting a link between the dysregulation in proinflammatory cytokine production and the aetiology of these metabolic diseases. While known as an immunomodulatory cytokine, Interleukin-15 (IL-15) has been shown to have effects on adipose tissue and induce weight loss in diet-induced obese mice. As weight loss improves glucose homeostasis, the goal of this study was to determine whether IL-15 impacts glucose regulation in a mouse model of diet-induced obesity. Our data demonstrate that IL-15 treatment significantly improves insulin sensitivity and glucose and insulin responses to an oral glucose challenge compared to obese counterparts and/or lean controls. These results show that IL-15 may be a novel therapeutic target for the treatment of obesity and its associated abnormal glucose regulation.

Complex chronic conditions among children born to women with schizophrenia.

PURPOSE: Maternal schizophrenia is linked to complications in offspring near the time of birth. Whether there is also a higher future risk of the child having a complex chronic condition (CCC) - a pediatric condition affecting any bodily system expected to last at least 12 months that is severe enough to require specialty care and/or a period of hospitalization - is not known. METHODS: In this population-based health administrative data cohort study (Ontario, Canada, 1995-2018), the risk for CCC was compared in 5066 children of women with schizophrenia (the exposed) vs. 2,939,320 unexposed children. Adjusted hazard ratios (aHR) were generated for occurrence of any CCC, by CCC category, and stratified by child sex, and child prematurity. RESULTS: CCC was more frequent in the exposed (7.7 per 1000 person-years [268 children]) than unexposed (4.2 per 100 person-years [124,452 children]) - an aHR of 1.25 (95% CI 1.10-1.41). aHRs were notably higher in 5 of 9 CCC categories: neuromuscular (1.73, 1.28-2.33), cardiovascular (1.94, 1.64-2.29), respiratory (1.83, 1.32-2.54), hematology/immunodeficiency (2.24, 1.24-4.05) and other congenital or genetic defect (1.59, 1.16-2.17). The aHR for CCC was more pronounced among boys (1.32, 1.13-1.55) than girls (1.16, 0.96-1.40), and of similar magnitude in term (1.22, 1.05-1.42) and preterm infants (1.18, 0.95-1.46). CONCLUSIONS: The risk for a CCC appears to be higher in children born to women with schizophrenia. This finding introduces opportunities for targeted preconception counselling, optimization of maternal risk factors, and intervention to support a vulnerable parent population who will experience unique challenges caring for a child with CCCs.

Rosiglitazone prevents diabetes by increasing beta-cell mass in an animal model of type 2 diabetes characterized by reduced beta-cell mass at birth.

AIM: Interventions that preserve or increase beta-cell mass may also prevent type 2 diabetes. Rosiglitazone prevents diabetes in people with high glucose levels who have impaired glucose tolerance and/or impaired fasting glucose. The effect of this drug on both glucose levels and beta-cell mass was studied in a rat model of diabetes, characterized by reduced beta-cell mass at birth with normoglycaemia, and progression to dysglycaemia with age. METHODS: Female Wistar rats were given either saline (vehicle) or nicotine during pregnancy and lactation. Offspring of saline-exposed dams were given vehicle and offspring of nicotine-exposed dams were randomized to receive either vehicle or rosiglitazone starting at weaning. Beta-cell mass, proliferation and apoptosis were determined at birth and at 4 and 26 weeks of age. Glucose homeostasis was examined following sequential oral glucose tolerance tests (OGTT). RESULTS: Rosiglitazone treatment prevented the development of dysglycaemia in nicotine-exposed animals. The ability of rosiglitazone to preserve normoglycaemia appeared to be because of its ability to increase beta-cell mass through a combination of enhanced beta-cell proliferation and decreased beta-cell apoptosis. CONCLUSIONS: These results suggest that if rosiglitazone administration is started prior to the onset of glucometabolic abnormalities, it prevents the onset of dysglycaemia by partially restoring beta-cell mass in animals with reduced beta-cell mass at birth.

Influence of dichlorodiphenylchloroethylene on vascular endothelial growth factor and insulin-like growth factor in human and rat ovarian cells.

1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE, DDE), a metabolite of DDT is a persistent hormonally active environmental toxicant present in human serum and follicular fluid. The objective of this study was to investigate the effects of DDE on the expression of the ovarian vascular endothelial growth factor (VEGF) and insulin-like growth factor (IGF-1) in primary cultures of human granulosa cells and in the rat ovary. Granulosa cells were obtained at the time of oocyte retrieval for in vitro fertilization and cultured with environmentally relevant concentrations of DDE. Immature female rats were treated with 100 microg DDE/kg body weight or vehicle at 28 and 31 days of age and then euthanized at 50 days of age for collection of ovarian tissue. Expression of VEGF, the VEGF receptor fetal liver kinase (Flk-1) and IGF-1 were determined by Western blotting analysis of protein lysates from granulosa cell cultures and by immunohistochemistry in the rat ovary. DDE at concentrations of 100-1000 ng/mL increased the expression of VEGF, Flk-1 and IGF-1 in vitro in primary cultures of human granulosa cells, with the highest expression occurring at 1000 ng/mL. Similarly, acute administration of DDE resulted in a significant increase in immunoreactive VEGF, Flk-1 and IGF-1 in the rat ovary. We conclude that DDE, at levels, which have been detected in humans, alters the expression of the ovarian growth factors VEGF and IGF-1 both in vivo and in vitro. This alteration in expression of growth factors may lead to altered ovarian function as seen in polycystic ovaries and impaired fertility.

Benzo-[a]-pyrene increases invasion in MDA-MB-231 breast cancer cells via increased COX-II expression and prostaglandin E2 (PGE2) output.

Benzo-[a]-pyrene (B[a]P), a carcinogenic component of cigarette smoke, has been shown to increase both COX-II expression and prostaglandin output in vascular smooth muscle and oral epithelial cells. In addition, invasive breast cancer cells have been reported to over express COX-II and PGE(2). Therefore, the objective of this study was to quantify the effect of increasing B[a]P concentrations on COX-II expression, PGE(2) output, and invasion using MDA-MB-231 cells, an invasive estrogen unresponsive breast cancer cell line. B[a]P significantly increased invasion in MDA-MB-231 cells at concentrations greater than 4 x 10(-8) M. Treatment of MDA-MB-231 cells with Vomitoxin (a selective COX-II inducer) enhanced invasion whereas co-treatment with NS398 (a selective COX-II inhibitor) attenuated B[a]P-induced invasion in MDA-MB-231 cells. Immunohistochemical staining and Western blots demonstrated a significant B[a]P treatment-induced increase in both the number of COX-II immunopositive MDA-MB-231 cells and COX-II protein levels. Moreover, B[a]P-treatment induced a profound (46 fold) increase in PGE(2) production by MDA-MB-231 cells. The aryl hydrocarbon receptor (AhR) antagonists resveratrol (RES) and alpha-naphthaflavone (alpha-NF) had no effect on their own, whereas B[a]P-induced invasion was significantly inhibited by co-treatment with RES and alpha-NF. Our data demonstrate that B[a]P-induced changes in invasion are mediated through augmented COX-II expression and PGE(2) production involving an AhR regulated pathway. Moreover, these results suggest a potential role for the AhR signalling pathway in breast cancer invasion.

Perinatal Administration of a Selective Serotonin Reuptake Inhibitor Induces Impairments in Reproductive Function and Follicular Dynamics in Female Rat Offspring.

INTRODUCTION: Up to 10% of pregnant women take antidepressants, of which selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed. Using a rodent model, we investigated the reproductive impacts of perinatal SSRI treatment on reproductive cyclicity and function in female offspring. METHODS: Virgin Wistar rats were given oral vehicle (n = 10) or fluoxetine hydrochloride (FLX, 10 mg/kg/d; n = 11) from 2 weeks prior to mating until weaning. Pubertal onset and reproductive cyclicity in offspring were assessed. Blood and ovarian tissues were collected for measures of reproductive function. RESULTS: Perinatal FLX tends to induce irregular reproductive cycles in adult offspring, which most commonly manifest as a prolonged estrus phase (FLX 34% vs control [CON] 10%) relative to CON offspring. The FLX offspring tended to have longer cycles (P = .052), had more secondary follicles (P = .0067), more total follicles (P = .0310), and increased apoptotic ovarian cells (P < .001). Prenatally exposed FLX offspring demonstrated elevated ovarian messenger RNA (mRNA) levels of ERß (P = .008), Cry1 (P = .043), and tryptophan hydroxylase 2 (P = .024), independent of stage of cycle. Ovarian mRNA levels of brain and muscle Arnt-like protein 1 (P = .046) and Pet-1 (P = .021) were increased in FLX offspring a manner that was reproductive cycle stage dependent. CONCLUSIONS: This is the first study to investigate the postnatal effects of maternal perinatal exposure to FLX on adult offspring reproduction. We show that genes that regulate serotonin signaling and action in the ovary are altered in prenatally FLX-exposed offspring, which when coupled with increased expression of components of the core Circadian Locomotor Output Cycles Kaput (CLOCK) gene regulatory loop may suggest an interaction between serotonergic signaling and clock gene signaling pathways leading to the altered reproductive phenotype.

Prostaglandin production at the onset of ovine parturition is regulated by both estrogen-independent and estrogen-dependent pathways.

A current hypothesis of ovine parturition proposes that fetal adrenal cortisol induces placental E2 production, which, in turn, triggers intrauterine PG production. However, recent evidence suggests that cortisol may directly increase PG production in trophoblast-derived tissues. To separate cortisol-dependent and estrogen-dependent PG production in sheep intrauterine tissues, we infused singleton, chronically catheterized fetuses beginning on day 125 of gestation (term, 147-150 days) with 1) cortisol (1.35 mg/h; n = 5); 2) cortisol and 4-hydroxyandrostendione, a P450aromatase inhibitor (4-OHA: 1.44 mg/h; n = 5); 3) saline (n = 5); or 4) saline and 4-OHA (n = 5). Fetal and maternal arterial blood samples were collected at 12-h intervals starting 24 h before infusion and continuing during treatment for 80 h or until active labor. Uterine contractility was measured by electromyogram recording of myometrial activity. Plasma E2, progesterone (P4), PGE2, and 13,14-dihydro- 15-keto-PGF2alpha were quantified by RIA. PGHS-II messenger RNA (mRNA) and protein expression were determined by in situ hybridization and Western blot analysis, respectively. Data were analyzed by ANOVA (P < or = 0.05). Labor-type uterine contractions were present after 68 h of cortisol infusion and had increased significantly by 80 h. Labor-type uterine contractions were induced after 68 h of cortisol plus 4-OHA infusion, but the contraction frequency remained less than that in the cortisol-treated animals. Fetal cortisol infusion increased fetal and maternal plasma E2 concentrations and decreased the maternal plasma P4 concentration significantly; concurrent 4-OHA infusion attenuated the increase in fetal and maternal plasma E2, but not the decrease in maternal plasma P4. The fetal plasma PGE2 concentration increased after both cortisol and cortisol plus 4-OHA infusion. The maternal plasma 13,14-dihydro-15-keto-PGF2alpha concentration rose after fetal cortisol infusion, but not after cortisol plus 4-OHA infusion. Placental trophoblast PGHS-II mRNA and protein expression were increased significantly after both cortisol and cortisol plus 4-OHA infusion. Endometrial PGHS-II mRNA and protein expression increased after cortisol infusion, but not after cortisol plus 4-OHA infusion. Plasma steroid and PG concentrations, uterine activity pattern, and intrauterine PGHS-II expression were not altered in either control group. We conclude that these data suggest distinct pathways of intrauterine PG synthesis: a cortisol-dependent/E2-independent mechanism within trophoblast tissue leading to elevations in fetal plasma PGE2, and an E2-dependent mechanism within maternal endometrium that leads to increased maternal plasma PGF2alpha and appears necessary for uterine activity and parturition.

Expression of prostaglandin I(2) synthase, but not prostaglandin E synthase, changes in myometrium of women at term pregnancy.

Prostaglandins (PGs) act as potent uterotonins at the time of labor. Prostaglandin E synthase (PGES) is responsible for the formation of PGE(2), a uterotonin. PGI(2) is synthesized by the prostaglandin I synthase enzyme (PGIS) and contributes to relaxation in the lower uterine segment. We examined the expression of membrane-bound PGES and PGIS in myometrium from pregnant women during preterm and term labor. Tissues were collected from the lower uterine segment from preterm no labor, preterm labor, term no labor, and term labor patients and used for immunohistochemistry and Western blot analysis using specific antibodies. Immunoreactive (ir-) PGES and PGIS proteins were localized to the cytoplasm of myocytes of the myometrium and vascular smooth muscle cells. Ir-PGES was also detected in vascular endothelial cells. Western blot analyses revealed a predominant protein band of 180 kDa, and a second 16-kDa band for ir-PGES and 56-kDa band for ir-PGIS. There was no significant change in ir-PGES protein (180 or 16 kDa) or mRNA levels with preterm or term labor or gestational age. There was a significant decrease in PGIS mRNA and protein with advancing gestational age. We conclude that the gestational age decrease in the inhibitory PGIS is consistent with lessening of its influence in myometrium at the time of labor. The lack of change in PGES indicates that alterations at other points along the pathway of arachidonic acid metabolism may be of greater importance in affecting local changes in PGE(2).

Differential changes in 15-hydroxyprostaglandin dehydrogenase and prostaglandin H synthase (types I and II) in human pregnant myometrium.

Prostaglandins (PGs) play a key role in the onset of labor in many species and regulate uterine contractility and cervical dilatation. Therefore, the regulation of prostaglandin output by PG synthesizing (PGHS-I and PGHS-II) and metabolizing (PGDH) enzymes in the human myometrium may determine uterine activity patterns in human labor both at preterm and at term. We hypothesized that expression of PGHS isozymes and PGDH in myometrium from women at preterm and term labor would change to favor increased uterotonin (PG) production. Myometrial samples were obtained from the lower uterine segment during cesarean section deliveries from women presenting in preterm, no labor; preterm, labor; term, no labor; term, labor. Immunoreactive (ir-) PGHS and PGDH protein was localized using immunohistochemistry, and changes in protein levels were determined by Western blotting. Ir-PGHS-I and PGHS-II proteins were localized only to myocytes. Ir-PGDH was localized to myocytes in all samples of myometrium examined, but using dual immunofluorescence and immunohistochemistry, ir-PGDH was also detected in cells of the connective tissue. Levels of ir-PGHS-I and PGHS-II protein were not significantly different between no labor and labor tissues, either at preterm or at term. There was no significant effect of gestational age on levels of PGDH, PGHS-I, and PGHS-II protein, but there was a significant decrease in ir-PGDH protein levels in myometrium with labor both at preterm and at term. In addition, there was a decrease in PGDH activity in myometrium from women in labor, both at preterm and at term. Therefore, we conclude that PGDH, PGHS-I, and PGHS-II protein localize within the myocytes of the human pregnant myometrium. A decrease in PGDH protein and activity occurs in association with active labor and may contribute to the amount of bioactive PGs available to act within the human pregnant myometrium at that time.

Effects of cortisol and oestradiol on hepatic 11beta-hydroxysteroid dehydrogenase type 1 and glucocorticoid receptor proteins in late-gestation sheep fetus.

In the late-gestation sheep, increased fetal plasma cortisol concentration and placental oestradiol (E(2)) output contribute to fetal organ maturation, in addition to the onset of parturition. Both cortisol and E(2) are believed to regulate the enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1), which interconverts bioactive 11-hydroxy glucocorticoids and their inactive 11-keto metabolites. 11beta-HSD1, abundantly expressed in fetal liver, operates primarily as a reductase enzyme to produce bioactive cortisol and thus regulates local hepatic glucocorticoid concentrations. Cortisol acts through the glucocorticoid receptor (GR) present in the liver. In this study, we examined the effects of cortisol and E(2) on hepatic 11beta-HSD1 and GR in the liver of chronically catheterized sheep fetuses treated with saline (n=5), cortisol (1.35 mg/h; n=5), saline+4-hydroxyandrostendione, a P450 aromatase inhibitor (4-OHA; 1.44 mg/h; n=5), or cortisol+4-OHA (n=5). Cortisol infusion resulted in increased plasma concentrations of fetal cortisol and E(2); concurrent administration of 4-OHA attenuated the increase in plasma E(2) concentrations. Using immunohistochemistry, we showed that fetal hepatocytes expressed both 11beta-HSD1 and GR proteins. Cortisol treatment increased GR in both cytosol and nuclei of hepatocytes; concurrent administration of 4-OHA was associated with distinct nuclear GR staining. Western blot revealed that cortisol, in the absence of increased E(2) concentrations, significantly increased concentrations of 11beta-HSD1 (34 kDa) and GR (95 kDa) proteins. 11beta-HSD1 enzyme activity was measured in the liver microsomal fraction in the presence of [(3)H]cortisone (10(-)(6) M) or [(3)H]cortisol (10(-)(6) M) and NADPH (reductase activity) or NADP(+) (dehydrogenase activity) respectively. 11beta-HSD1 reductase activity was significantly greater in the presence of cortisol. In summary, we found that, in sheep during late gestation, cortisol increased both 11beta-HSD1 and GR in the fetal liver, and these effects were accentuated in the absence of increased E(2).

Correlations of plasma growth hormone with somatostatin, gonadal steroid hormones and thyroid hormones in rainbow trout during sexual recrudescence.

The study explores the interrelationships among growth hormone (GH), somatostatin-14 (SRIF), non-esterified fatty acids (NEFA), gonadal steroid hormones and thyroid hormones (THs) in sexually recrudescent rainbow trout (Oncorhynchus mykiss) to examine aspects of the complex set of physiological changes associated with gonadal growth and maturation. Females exhibited significant decreases in plasma SRIF, NEFA and triiodo-L-thyronine (T3) concentrations, and a significant increase in plasma GH concentration associated with gonadal maturation, whereas in males, only SRIF and NEFA concentrations showed significant changes during testicular maturation. The declining SRIF levels during gonadal recrudescence may indicate a role for the hormone in the energy repartitioning processes that occur in both sexes at this time. Correlation analysis of plasma variables revealed a direct correlations between plasma NEFA and 17 beta-estradiol (E2) in females, an inverse correlation between NEFA and testosterone (T) in males, inverse correlations between GH and SRIF in both males and females, and inverse correlations between THs and SRIF concentrations in females. These marked gender differences in correlations likely reflect the different physiological challenges faced by the two sexes and emphasizes the need to consider gender, as well as maturity when studying the interactions of hormones.

Chronic prenatal ethanol exposure increases adiposity and disrupts pancreatic morphology in adult guinea pig offspring.

BACKGROUND: Ethanol consumption during pregnancy can lead to a range of adverse developmental outcomes in children, termed fetal alcohol spectrum disorder (FASD). Central nervous system injury is a debilitating and widely studied manifestation of chronic prenatal ethanol exposure (CPEE). However, CPEE can also cause structural and functional deficits in metabolic pathways in offspring. OBJECTIVES AND METHODS: This study tested the hypothesis that CPEE increases whole-body adiposity and disrupts pancreatic structure in guinea pig offspring. Pregnant guinea pigs received ethanol (4 g kg(-1) maternal body weight per day) or isocaloric-sucrose/pair-feeding (control) for 5 days per week throughout gestation. RESULTS: Male and female CPEE offspring demonstrated growth restriction at birth, followed by a rapid period of catch-up growth before weaning (postnatal day (PD) 1-7). Whole-body magnetic resonance imaging (MRI) in young adult offspring (PD100-140) revealed increased visceral and subcutaneous adiposity produced by CPEE. At the time of killing (PD150-200), CPEE offspring also had increased pancreatic adipocyte area and decreased ß-cell insulin-like immunopositive area, suggesting reduced insulin production and/or secretion from pancreatic islets. CONCLUSION: CPEE causes increased adiposity and pancreatic dysmorphology in offspring, which may signify increased risk for the development of metabolic syndrome and type 2 diabetes mellitus.

The role of dysregulated glucose metabolism in epithelial ovarian cancer.

Epithelial ovarian cancer (EOC) is the most lethal gynecologic cancer and also one of the most poorly understood. Other health issues that are affecting women with increasing frequency are obesity and diabetes, which are associated with dysglycemia and increased blood glucose. The Warburg Effect describes the ability of fast-growing cancer cells to preferentially metabolize glucose via anaerobic glycolysis rather than oxidative phosphorylation. Recent epidemiological studies have suggested a role for hyperglycemia in the pathogenesis of a number of cancers. If hyperglycemia contributes to tumour growth and progression, then it is intuitive that antihyperglycemic drugs may also have an important antitumour role. Preliminary reports suggest that these drugs not only reduce available plasma glucose, but also have direct effects on cancer cell viability through modification of molecular energy-sensing pathways. This review investigates the effect that hyperglycemia may have on EOC and the potential of antihyperglycemic drugs as therapeutic adjuncts.

Effects of rosiglitazone on ovarian function and fertility in animals with reduced fertility following fetal and neonatal exposure to nicotine.

We have previously shown that in utero nicotine exposure causes impaired fertility, follicle immaturity, and ovarian dysfunction in adult female rat offspring. These characteristics overtly resemble the clinical profile of polycystic ovarian syndrome (PCOS) and recent studies have shown that thiazolidinediones such as rosiglitazone improve fertility in women with PCOS but the mechanism is not well defined. Our goal was to examine whether rosiglitazone would (1) ameliorate the altered ovarian physiology that occurs following fetal and neonatal exposure to nicotine and (2) to examine whether this could be due to normalization of ovarian vascularization. At weaning, offspring of nicotine-exposed dams were given either vehicle (NV) or rosiglitazone (3 mg kg(-1) day(-1); NR). Offspring of saline-exposed dams received vehicle (SV). Tissues were collected when the female offspring reached 26 weeks of age. NV animals had reduced granulosa cell proliferation and increased ovarian cell apoptosis. Treatment with rosiglitazone increased proliferation, and decreased apoptosis, compared NV animals. NV animals had decreased ovarian vascularity relative to controls, whereas NR animals had an intermediate level of ovarian vessel density. Moreover, ovaries from NV animals had decreased levels of the pro-angiogenic growth factors vascular endothelial growth factor (VEGF) and endocrine gland-derived VEGF both of which were increased with rosiglitazone treatment. Rosiglitazone reversed some of the nicotine effects in the ovary and increased ovarian vascularization, follicle maturation and improved oocyte competence. Rosiglitazone may be an important treatment option for PCOS and the present study provides a potential mechanism by which rosiglitazone may have beneficial effects on fertility in these patients.

Atrazine-induced changes in aromatase activity in estrogen sensitive target tissues.

Atrazine (ATR) is a pesticide used widely throughout North America. Although not directly estrogenic, ATR treatment has been shown to increase aromatase activity in tumor cell lines. Thus, it is suggested that ATR can increase local tissue estrogen levels in estrogen sensitive target tissues through increased aromatase activity. Therefore the effect of ATR on aromatase activity was measured in human granulosa-lutein cell cultures, cells that abundantly express aromatase, and endometrial stromal cell (ESC) cultures, cells that do not express aromatase. Aromatase activity was quantified by the tritiated water method and the specificity of the assay was confirmed by co-incubation with 4-hydroxyandrostenedione, an irreversible inhibitor of the catalytic activity of aromatase. Aromatase activity in ATR treated (1-10 microm) granulosa-lutein cells was increased more than 2-fold compared with control cultures. There were no treatment related changes in cellular protein and thus it is suggested that the ATR-induced change in aromatase activity was not due to an increase in cell number. ATR-treatment had no effect on ESC aromatase activity at any concentration tested. Similarly, there was no effect of ATR treatment on human recombinant aromatase activity in our cell-free test system. Therefore it is concluded that microm concentrations of ATR can increase aromatase activity of human granulosa cells but not ESC and this effect is not elicited at the enzyme level.

Fetal and neonatal exposure to nicotine disrupts ovarian function and fertility in adult female rats.

Women born to mothers who smoked during pregnancy have been shown to have impaired fertility, although the mechanisms underlying this association are unknown. Nicotine administration in adult animals has adverse effects on the ovary and uterus; however, the effects of fetal exposure to nicotine on postnatal ovarian function have not been determined. The goal of this study was to assess the effect of fetal and neonatal exposure to nicotine on ovarian function and fertility of the offspring. Nulliparous female Wistar rats were given 1 mg.kg-1.d-1 nicotine bitartrate, subcutaneously for 14 d prior to mating, during pregnancy and throughout lactation until weaning. Measures of fertility, breeding success, and serum levels of ovarian steroid hormones in offspring were assessed at 4 and 6 mo of age. Fetal and neonatal exposure to nicotine significantly increased the time to pregnancy as the animals aged. Similarly, evidence of altered ovarian steroidogenesis including increased serum progesterone concentrations and a decreased estrogen:progesterone ratio was observed in 6-mo-old animals. We conclude that fetal and neonatal exposure to nicotine results in delayed ovarian dysfunction in adult female offspring.

The pattern of glucocorticoid and estrogen receptors may explain differences in steroid dependency of intrauterine prostaglandin production at parturition in sheep.

BACKGROUND: We have recently described two distinct pathways of intrauterine prostaglandin (PG) synthesis: a cortisol-dependent/estradiol-independent mechanism within trophoblast tissue leading to elevations in fetal plasma PGE2, and an estradiol-dependent mechanism within maternal endometrium that leads to increased maternal plasma PGF2(2alpha). We hypothesized that the differential effects of cortisol and estradiol on intrauterine PGH synthase-II (PGHS-II) expression and PG production may be because of the tissue specific expression of the glucocorticoid and estradiol receptors (GR and ER, respectively) within the intrauterine tissues. In addition, we suggest that these two pathways of PG production are linked through the expression of P450(C17hydroxylase) (P450(C17)) and subsequent increase in placental estradiol synthesis. METHODS: To test the hypotheses, we infused singleton, chronically catheterized fetal sheep beginning at day 125 of gestation (term 147 to 150 days) with (1) cortisol (0.45 mg/mL; n = 5); (2) cortisol and 4-hydroxyandrostenedione, a P450(aromatase) inhibitor (4-OHA: 1.44 mg/h; n = 5); (3) saline (n = 5); or (4) saline and 4-OHA (n = 5). PGHS-II, ER alpha, ER beta, and GR alpha were localized using immunohistochemistry. ER alpha, ER beta, P450(C17), and GR alpha protein expressions were determined by Western blot analysis. Data were analyzed by analysis of variance (ANOVA) (P < or =.05). RESULTS: Fetal cortisol infusion in the presence or absence of a rise in placental estrogen synthesis increased placental expression of GR alpha; both PGHS-II and GR alpha localized to the uninucleate trophoblast cells of the placentome and were excluded from the maternal stroma and binucleate cells. Both forms of ER were excluded from the trophoblast tissue of the placentome. ER alpha, ER beta, and PGHS-II showed a similar pattern of distribution within the luminal epithelium of the endometrium; there were no alterations in the level of the ER in the presence of cortisol +/- 4-OHA. Placental P450(C17) protein expression was increased in the presence of a rise in fetal cortisol independent of changes in placental estrogen synthesis. CONCLUSIONS: We concluded that the differential effects of cortisol and estradiol on intrauterine PGHS-II expression and PG production may be due to the tissue-specific expression of the GR and ER within the intrauterine tissues. Glucocorticoid effects on trophoblast PG production may be mediated in a positive feed-forward manner. We further suggest that either cortisol or a cortisol-stimulated intermediate, like PGE2, increased P450(C17) expression, leading to a rise in placental estradiol synthesis and triggering maternal intrauterine tissue PG production.

Fetal and neonatal exposure to nicotine in Wistar rats results in increased beta cell apoptosis at birth and postnatal endocrine and metabolic changes associated with type 2 diabetes.

AIMS/HYPOTHESIS: Epidemiological studies report an increased risk of obesity and type 2 diabetes in children born to women who smoked during pregnancy. This study examines the effect of fetal and neonatal exposure to nicotine, the major addictive component of cigarettes, on postnatal growth, adiposity and glucose homeostasis. METHODS: Female Wistar rats were given either saline (vehicle) or nicotine (1 mg kg(-1) day(-1)) during pregnancy and lactation. Serum and pancreas tissue were collected from the infant rats at birth. Postnatal growth was assessed weekly until the rats reached 26 weeks of age and glucose homeostasis was examined by OGTTs performed at 7 and 26 weeks of age. RESULTS: Exposure to nicotine resulted in increased postnatal growth and adiposity. Nicotine exposure also resulted in dysglycaemia at 7 and 26 weeks of age. Serum insulin concentrations were decreased in the pups exposed to nicotine at birth. This was associated with increased beta cell apoptosis (pups of saline-treated mothers 8.8+/-1.21% apoptotic beta cells; pups of nicotine-treated mothers 27.8+/-3.1% apoptotic beta cells). CONCLUSIONS/INTERPRETATION: Fetal and neonatal exposure to nicotine results in metabolic changes in the offspring that are consistent with obesity and type 2 diabetes. We propose that these metabolic changes may be a consequence of the initial insult to the beta cell during fetal life and that this animal model has many characteristics of diabetes in humans.