Biomedical subjects

Margaret Warner

Publications and source records attributed to Margaret Warner.

At least 19 recordsLinked to original sources

PubMed2006

Ovarian wedge resection restores fertility in estrogen receptor beta knockout (ERbeta-/-) mice.

Ovulation rarely occurs in mice in which the estrogen receptor beta (ERbeta) gene has been inactivated (ERbeta-/- mice). Here, we investigated whether this subfertility is due to a defect in the ovary itself or to more general endocrine changes in ERbeta-/- mice. We transplanted ERbeta-/- ovaries into WT mice and WT ovaries into ERbeta-/- mice. Upon mating with ERbeta-/- males, fertility increased from 20% in control intact ERbeta-/- group to 40% in the WT recipients with ERbeta-/- ovaries. The transplantation procedure was not efficient, and when WT ovaries were transplanted into WT mice, fertility was only 36%. Surgical ovarian wedge resection, a procedure which induces ovulation in anovulatory women with polycystic ovarian syndrome, resulted in 100% fertility of ERbeta-/- mice. In ERbeta-/- mice, as the follicles enlarged, the thecal layer remained very compact (revealed by H&E and collagen staining), and there was no increase in vascularization (measured as smooth muscle actin). In addition, there was an increase in PDGF receptor alpha (PDGFRalpha) and a decrease in PDGFbeta expression in the granulosa cells, similar to what has been found in follitropin receptor knockout mice. After wedge resection, expression of both smooth muscle actin and PDGFRs was normalized. During normal follicular development, increased vascularization of the thecal layer is a prerequisite for further follicular growth. We suggest that the defect in ERbeta-/- mouse ovaries is a failure of communication between the granulosa and thecal layers. The follicles do not mature because of insufficient blood supply. This problem is overcome by stimulating neovascularization by simple wedge resection of the ovaries.

Animals↗

PubMed2006

Estrogen receptor beta expression in the embryonic brain regulates development of calretinin-immunoreactive GABAergic interneurons.

Our previous studies with estrogen receptor beta knockout (ERbeta(-/-)) mice demonstrated that ERbeta is necessary for embryonic development of the brain as early as embryonic day 14.5 (E14.5) and is involved in neuronal migration. Such early effects of ER were unexpected because estradiol synthesis and action in the brain occur at E18.5. In the present study, we examined the distribution of ERbeta in the developing brain and identified a population of ERbeta-regulated interneurons. ERbeta appears in the brain at E12.5, mainly localized in the wall of the midbrain, neuromere, hypothalamus, thalamus, and basal plate of pons. At E15.5 and E16.5, ERbeta expression increased in the hypothalamus, thalamus, and midbrain and appeared in the limbic forebrain. At E18.5, ERbeta expression was strongly expressed throughout the brain, including the cerebellum and striatum, whereas there were very few positive cells in the ventricular region. In the paraventricular thalamic nucleus and parafascicular nucleus, most of the calretinin-immunopositive interneurons expressed ERbeta. In ERbeta(-/-) mice, calretinin expression was markedly lower than in WT mice in the hippocampus, thalamus, and amygdala both at E16.5 and at E18.5. Epidermal growth factor receptor expression was lower in the cortex of ERbeta(-/-) than in WT mice at E15.5 and, unlike WT mice, was absent from the superficial marginal zone. These findings suggest that ERbeta in the embryonic brain is necessary for the development of calretinin-immunoreactive GABAergic interneurons and for neuronal migration in the cortex through modulating epidermal growth factor receptor expression at middle and later embryonic stages.

Animals↗

PubMed2006

Role of estrogen receptor beta in uterine stroma and epithelium: Insights from estrogen receptor beta-/- mice.

In this study, we compared the uterine tissue of estrogen receptor (ER)beta(-/-) mice and their WT littermates for differences in morphology, proliferation [the percentage of labeled cells 2 h after BrdUrd injection and EGF receptor (EGFR) expression], and differentiation (expression of progesterone receptor, E-cadherin, and cytokeratins). In ovariectomized mice, progesterone receptor expression in the uterine epithelium was similar in WT and ERbeta(-/-) mice, but E-cadherin and cytokeratin 18 expression was lower in ERbeta(-/-) mice. The percentage of cells in S phase was 1.5% in WT mice and 8% in ERbeta(-/-) mice. Sixteen hours after injection of 17beta-estradiol (E(2)), the number of BrdUrd-labeled cells increased 20-fold in WT mice and 80-fold in ERbeta(-/-) mice. Although ERalpha was abundant in intact mice, after ovariectomy, ERalpha could not be detected in the luminal epithelium of either WT or ERbeta(-/-) mice. In both untreated and E(2)-treated mice, ERalpha and ERbeta were colocalized in the nuclei of many stromal and glandular epithelial cells. However, upon E(2) + progesterone treatment, ERalpha and ERbeta were not coexpressed in any cells. In WT mice, EGFR was located on the membranes and in the cytoplasm of luminal epithelium, but not in the stroma. In ERbeta(-/-) mice, there was a marked expression of EGFR in the nuclei of epithelial and stromal cells. Upon E(2) treatment, EGFR on cell membranes was down-regulated in WT but not in ERbeta(-/-) mice. These findings reveal an important role for ERbeta in response to E(2) and in the organization, growth, and differentiation of the uterine epithelium.

Animals↗

PubMed2006

Lung dysfunction causes systemic hypoxia in estrogen receptor beta knockout (ERbeta-/-) mice.

Estrogen receptor beta (ERbeta) is highly expressed in both type I and II pneumocytes as well as bronchiolar epithelial cells. ERalpha is not detectable in the adult lung. Lungs of adult female ERbeta knockout (ERbeta-/-) mice have already been reported to have fewer alveoli and reduced elastic recoil. In this article, we report that, by 5 months of age, there are large areas of unexpanded alveoli in lungs of both male and female ERbeta-/- mice. There is increased staining for collagen and, by EM, abnormal clusters of collagen fibers are seen in the alveolar septa of ERbeta-/- mice. Immunohistochemical analysis and Western blotting with lung membrane fractions of ERbeta-/- mice revealed down-regulation of caveolin-1, increased expression of membrane type-1 metalloproteinase, matrix metalloproteinase 2 (active form), and tissue inhibitors of metalloproteinases 2. Hypoxia, measured by immunohistochemical analysis for hypoxia-inducible factor 1alpha and chemical adducts (with Hypoxyprobe), was evident in the heart, ventral prostate, periovarian sac, kidney, liver, and brain of ERbeta-/- mice under resting conditions. Furthermore, both male and female adult ERbeta-/- mice were reluctant to run on a treadmill and tissue hypoxia became very pronounced after exercise. We conclude that ERbeta is necessary for the maintenance of the extracellular matrix composition in the lung and loss of ERbeta leads to abnormal lung structure and systemic hypoxia. Systemic hypoxia may be responsible for the reported left and right heart ventricular hypertrophy and systemic hypertension in ERbeta-/- mice.

Animals↗

PubMed2006

Role of estrogen receptor beta in colonic epithelium.

Several papers report that the colon is one of the tissues regulated by estrogen receptor (ER)beta. To better understand the physiological role of ERbeta in colonic tissue, we have compared morphology, proliferation, and differentiation of colonic epithelium in ERbeta-/- mice and WT littermates. BrdUrd labeling revealed that the number of proliferating cells was higher in ERbeta-/- mice and that the migration of labeled cells toward the luminal surface was faster in ERbeta-/- mice than in WT littermates. Additionally, in the absence of ERbeta, there was a decrease in apoptosis, which was measured by immunohistochemical staining of cleaved caspase-3. The state of differentiation of the colonic epithelial cells was studied by using epithelial markers. In ERbeta-/- mice, there was a significant decrease in the expression of the differentiation marker cytokeratin (CK)20 and in the cellular adhesion molecules alpha-catenin (an adherens junction protein) and plectin (a hemidesmosomal protein). These changes were also evident by electron microscopy as abnormalities in tight junctions and in the number and shape of desmosomes in ERbeta-/- mice. These findings suggest a role for ERbeta in the organization and architectural maintenance of the colon. Furthermore, our results indicate that the rapidly proliferating cells of the colonic epithelium in ERbeta-/- mice are lost by increased shedding and not by increased apoptosis. In this way, hyperproliferative cells that lack ERbeta do not form hyperplastic lesions and do not accumulate in the superficial epithelium.

Animals↗

PubMed2006

Deaths: injuries, 2002.

OBJECTIVES: This report presents injury mortality data for 2002 using the external-cause-of-injury mortality matrix for the International Classification of Diseases, Tenth Revision (ICD-10). The external cause matrix is a detailed and comprehensive framework for tabulating and presenting injury deaths by mechanism and intent of death. Data are presented by age, sex, race, Hispanic origin, and State. In addition, trend data are shown for 1999-2002 by age, sex, and mechanism and intent of injury. This report also introduces the injury mortality diagnosis matrix. This latter is another framework that categorizes the nearly 1,200 injury diagnosis codes from ICD-10's chapter 19 according to body region and nature of the injury diagnosis information captured in the multiple-cause-of-death fields of the national mortality file. This report supplements the annual report of final mortality statistics. METHODS: Data in this report are based on information from all death certificates filed in the 50 States and the District of Columbia in 2002. Causes of death and nature of injury are processed and coded in accordance with the ICD-10. RESULTS: In 2002, 161,269 resident deaths occurred as the result of injuries. Of these injury deaths, 66.2 percent were classified as unintentional, 19.6 percent were suicides, 10.9 percent were homicides, 3.0 percent were of undetermined intent, and 0.3 percent involved legal intervention or operations of war. The five leading mechanisms of injury death were motor vehicle traffic, firearm, poisoning, falls, and suffocation, accounting for 81 percent of all injury deaths. The rate of poisoning deaths increased by 17.9 percent between 2001 and 2002, but the reader is advised to interpret these numbers cautiously as a portion of this increase is due to stricter procedures concerning data processing that were implemented in 2002. Thirty percent of injuries resulting in death were to the head and neck region with the vast majority of these classified as traumatic brain injury. Injuries involving the whole body system accounted for 28 percent of all injuries mentioned (17 percent were poisoning and 7 percent were other effects of external causes, such as submersion or asphyxiation). CONCLUSIONS: Injury mortality data presented in this report using the external cause-of-injury mortality matrix for ICD-10 provide detail on the mechanism of death needed for research and other activities related to injury prevention. This report highlights the importance of multiple causes-of-death data when analyzing injury mortality--special attention is given to the issue of accuracy and completeness of information as it pertains to these data. The Centers for Disease Control and Prevention's (CDC) National Center for Health Statistics (NCHS) is involved in several ongoing projects related to the study of injury and injury mortality.

Adolescent↗

PubMed2006

Muscle GLUT4 regulation by estrogen receptors ERbeta and ERalpha.

Estrogen is known to influence glucose homeostasis with dominant effects in the liver, but the role of estrogen receptors in muscle glucose metabolism is unknown. In the present study, we investigated the expression of the two estrogen receptors, ERalpha and ERbeta, and their influence on regulation of the glucose transporter, GLUT4, and its associated structural protein, caveolin-1, in mouse gastrocnemius muscle. Immunohistochemical analysis revealed that ERalpha and ERbeta are coexpressed in the nuclei of most muscle cells, and that their levels were not affected by absence of estradiol [in aromatase-knockout (ArKO) mice]. GLUT4 expression on the muscle cell membrane was not affected by loss of ERbeta but was extremely reduced in ERalpha(-/-) mice and elevated in ArKO mice. RT-PCR confirmed a parallel reduction in GLUT4 mRNA levels in ERalpha(-/-) mice. Upon treatment of ArKO mice with the ERbeta agonist 2,3-bis(4-hydroxyphenyl)propionitrile, GLUT4 expression was reduced. By immunofluorescence and Western blotting, caveolin-1 expression was higher in ArKO mice and lower in ERbeta(-/-) and ERalpha(-/-) mice than in WT littermates. GLUT4 and caveolin-1 were colocalized in WT and ArKO mice but not in ERbeta(-/-) and ERalpha(-/-) mice. These results reveal that ERalpha is a positive regulator of GLUT4 expression, whereas ERbeta has a suppressive role. Both ERbeta and ERalpha are necessary for optimal caveolin-1 expression. Taken together, these results indicate that colocalization of caveolin-1 and GLUT4 is not an absolute requirement for muscle glucose metabolism but that reduction in GLUT4 could be contributing to the insulin resistance observed in ERalpha(-/-) mice.

Animals↗

PubMed2006

Differential expression of oestrogen receptors in human secondary lymphoid tissues.

Many autoimmune diseases including rheumatoid arthritis (RA), Sjögren's syndrome (SS) and systemic lupus erythematosus (SLE) occur much more frequently in women than in men. There is much evidence that oestrogen is the major cause of this gender difference. Interestingly, oestrogen relieves the symptoms of RA and SS but it exacerbates SLE. This contradictory effect of oestrogen on autoimmune diseases is not well understood. Most of the effects of oestrogen are mediated by two receptors: oestrogen receptor alpha and beta (ERalpha and ERbeta). To determine whether these contradictory effects of oestrogen relate to the involvement of distinct effects of the two ERs, we investigated expression of ERalpha and ERbeta in human secondary lymphoid tissues. We observed that, in tonsils, ERbeta is expressed in lymphocytes of germinal centres (GC) and the follicular mantle zone as well as in granulocytes, while ERalpha is expressed only in activated germinal centres but not in the follicular zone. ERbeta is the predominant ER in human leucocytes from peripheral blood, spleen and in leucocytes infiltrating cancers in both males and females. In addition, in different human lymphoma cell lines including Hodgkin lymphoma, Burkitt lymphoma, and multiple myeloma, ERbeta is abundant while ERalpha is not detectable. Our results indicate that ERbeta is the predominant type of ER in mature lymphocytes. We suggest that ERalpha and ERbeta have distinct roles in secondary lymphoid tissues and that further studies with ERbeta-specific agonists will help to elucidate the role of ERbeta in these tissues.

Adult↗

PubMed2006

Clinical presentation, temporal relationship, and outcome in thirty-three patients with type 2 heparin-induced thrombocytopenia after cardiotomy.

BACKGROUND: Type 2 heparin-induced thrombocytopenia is an uncommon but often fatal complication of heparin, frequently difficult to diagnose after cardiac surgery. In this series, we record the clinical presentation, temporal relationship, and treatment outcome of patients diagnosed with heparin-induced thrombocytopenia postoperatively. METHODS: Thirty-three consecutive patients (1.1%) with a diagnosis of heparin-induced thrombocytopenia established by a greater than 50% drop in platelet count with or without a thrombotic event and a positive platelet factor-4 assay were reviewed. We recorded the clinical presentation, the time to presentation, treatment, and outcome (thrombosis, mortality). Univariate analysis was performed on 13 preoperative, operative, and postoperative variables. RESULTS: The cohort was at increased mortality risk as a result of age (69.4 years), reduced cardiac function (46.8%), nonbypass operations (57.6%), emergency surgery (21.2%), and implantation of three assist devices. The mean time to suspect heparin-induced thrombocytopenia postoperatively was 5.4 days, with 22 cases (66.6%) occurring within 5 days. All patients had previous (within 3 months) exposure to heparin, and 66.6% had ongoing treatment with heparin before surgery. Overall mortality was 33%; thrombotic complications occurred in 15 patients (45.5%), with a mortality of 7 (46.6%) despite immediate cessation of heparin and treatment with a nonheparin analog. Thrombocytopenia without thrombosis occurred in 18 patients (54.5%), but a subgroup of 5 patients with nonthrombotic complications accounted for the 4 (22.2%) deaths. CONCLUSIONS: Heparin-induced thrombocytopenia after cardiac surgery is uncommon but may occur within 5 days of surgery, further complicating diagnosis and treatment. Thrombotic complications result in a high mortality despite treatment with a nonheparin analog, and a subgroup of patients with thrombocytopenia fared poorly.

Aged↗

PubMed2005

Nongenomic effects of estrogen: why all the uncertainty?

It is clear that estradiol has profound, rapid effects on the conformation of the estrogen receptors (ERs), ERalpha and ERbeta, which mediate the transcriptional effects of estradiol. Estrogen can elicit many other rapid changes in cells including changes in ion fluxes across membranes and stimulation of kinases and phosphatases. The proteins which are the targets of these actions are the subject of intense investigation. One of the issues that have not been satisfactorily resolved is whether ERalpha or ERbeta can reside in the plasma membrane and participate in the rapid effects of estrogen. In the present commentary, we take a careful look at some of the published data in an attempt to understand why it is so difficult to obtain a definitive answer to this question.

Animals↗

PubMed2005

Aminoglycoside suppression of nonsense mutations in severe hemophilia.

Aminoglycoside antibiotics exhibit their bactericidal effect by interfering with normal ribosomal activity. In this pilot study, we have evaluated the effect of the aminoglycoside antibiotic gentamicin on the factor VIII (FVIII) and IX levels of severe hemophiliacs with known nonsense mutations. Five patients were enrolled and each patient was given 3 consecutive days of gentamicin at a dose of 7 mg/kg intravenously every 24 hours. Two patients (patient no. 1: hemophilia A, Ser1395Stop; and patient no. 5: hemophilia B, Arg333Stop) showed a decrease in their activated partial thromboplastin time (aPTT), an increase in their FVIII (0.016 IU/mL, 1.6%) or FIX (0.02 IU/mL, 2%) levels, and an increase in thrombin generation. The remaining 3 patients (patient no. 2: hemophilia B, Arg252Stop; patient no. 3: hemophilia A, Arg2116Stop; and patient no. 4: hemophilia A, Arg427Stop) showed no response in the aPTTs or factor levels, but one (patient no. 2: hemophilia B, Arg252Stop) showed an increase in the factor IX antigen level (2%-5.5%) that persisted throughout the period of the study and was concordant with an increase in thrombin generation. Gentamicin is unlikely to be an effective treatment for severe hemophilia due to its potential toxicities and the minimal response documented in this report. This study, however, does provide a proof of principle, suggesting that ribosomal interference with a less toxic agent may be a potential therapeutic mechanism for severe hemophilia patients with nonsense mutations.

Aminoglycosides↗

PubMed2005

Estrogen receptor beta in health and disease.

Estrogens, acting through its two receptors, ESR1 (hereafter designated ER alpha) and ESR2 (hereafter designated ER beta), have diverse physiological effects in the reproductive system, bone, cardiovascular system, hematopoiesis, and central and peripheral nervous systems. Mice with inactivated ER alpha, ER beta, or both show a number of interesting phenotypes, including incompletely differentiated epithelium in tissues under steroidal control (prostate, ovary, mammary, and salivary glands) and defective ovulation reminiscent of polycystic ovarian syndrome in humans (in ER beta-/- mice), and obesity, insulin resistance, and complete infertility (both in male and female ER alpha-/- mice). Estrogen agonists and antagonists are frequently prescribed drugs with indications that include postmenopausal syndrome (agonists) and breast cancer (antagonists). Because the two estrogen receptors (ERs) have different physiological functions and have ligand binding pockets that differ enough to be selective in their ligand binding, opportunities now exist for development of novel ER subtype-specific selective-ER modulators.

Animals↗

PubMed2005

Increased estrogen receptor betacx expression during mammary carcinogenesis.

Identification of proteins that markedly vary during early steps of mammary carcinogenesis may help to understand its pathophysiology and to develop a prevention strategy. The expression of total estrogen receptor beta (ERbeta) protein and of its COOH-terminally spliced variant ERbetacx (or ERbeta2) was compared in 43 invasive breast cancers and in 39 adjacent normal mammary glands and 26 ductal carcinoma in situ (DCIS). Thirty-six breast cancers were ER positive by radioligand binding assay. The analysis was done by immunohistochemistry on adjacent sections of formalin-fixed, paraffin-embedded tumors using polyclonal anti-ERbeta 503 IgY and sheep polyclonal ERbetacx antibodies that were previously validated. Nuclear staining was quantified using a computerized image analyzer in selected areas of normal and cancer epithelial cells. Total ERbeta expression was high in normal glands, decreased in DCIS (P = 0.0004), and increased from DCIS to invasive tumors (P = 0.029). In contrast, the ERbetacx expression was low in normal glands, increased significantly in DCIS (P = 0.0014), and continued to increase in invasive carcinomas (P = 0.0027) in both ERalpha-positive and ERalpha-negative tumors. This is the first study showing a significant increase of the ERbetacx variant protein in DCIS and invasive breast cancer compared with adjacent normal glands. This contrasts with the decrease of the total ERbeta level in the same patients and indicates different mechanisms to explain these variations during mammary carcinogenesis. It also suggests a role of the ERbetacx variant in carcinogenesis opposite to the protective effect of the wild-type ERbeta1.

Alternative Splicing↗

PubMed2005

Reflections on the discovery and significance of estrogen receptor beta.

We have known for many years that estrogen is more than the female hormone. It is essential in the male gonads, and in both sexes, estrogen has functions in the skeleton and central nervous system, on behavior, and in the cardiovascular and immune systems. An important aspect of the discovery of estrogen receptor (ER) beta is that the diverse functions of estrogen can now be divided into those mediated by ERalpha and those mediated by ERbeta. Pharmacological exploitation of this division of the labors of estrogen is facilitated by the ligand-binding specificity and selective tissue distribution of the two ERs. Because the ligand binding domains of ERalpha and ERbeta are significantly different from each other, selective ligands can be (and have been) developed to target the estrogenic pathway that is malfunctioning, without interfering with the other estrogen-regulated pathways. Because of the absence of ERbeta from the adult pituitary and endometrium, ERbeta agonists can be used to target ERbeta with no risk of adverse effects from chemical castration and uterine cancer. Some of the diseases in which there is hope that ERbeta agonists will be of benefit are prostate cancer, autoimmune diseases, colon cancer, malignancies of the immune system, and neurodegeneration.

Animals↗

PubMed2005

Inactivation of liver X receptor beta leads to adult-onset motor neuron degeneration in male mice.

Male mice with inactivated liver X receptor (LXR) beta suffer from adult-onset motor neuron degeneration. By 7 months of age, motor coordination is impaired, and this condition is associated with lipid accumulation and loss of motor neurons in the spinal cord, together with axonal atrophy and astrogliosis. Several of these features are reminiscent of the neuropathological signs of chronic motor neuron disease such as amyotrophic lateral sclerosis. Because the LXRs are important for cholesterol and lipid metabolism, we speculate that absence of LXRbeta leads to pathological accumulation of sterols and lipids that may themselves be neurotoxic or may modulate intracellular pathways and thereby predispose motor neurons to degeneration.

Amyotrophic Lateral Sclerosis↗

PubMed2005

Early onset of puberty and early ovarian failure in CYP7B1 knockout mice.

CYP7B1 is the enzyme responsible for hydroxylation and termination of the estrogenic actions of the androgen metabolite, 5alpha-androstane-3beta, 17beta-diol (3betaAdiol). 3betaAdiol is estrogenic in ERalpha or ERbeta positive cells only if they do not express CYP7B1. In this study we show that female CYP7B1(-/-) mice experience early onset of growth of the uterus and mammary glands and commence estrus cycles 2 days earlier than their wild-type littermates. Adult mammary glands and uteri appear to be under continuous estrogenic stimulation. We conclude that, by cell-specific regulation of the estrogenicity of 3betaAdiol, CYP7B1 performs two major tasks: (i) it allows 3betaAdiol to have growth inhibitory effects through ERbeta and (ii) it permits estradiol-specific activation of estrogen receptors by protection of certain cells from the estrogenic effects of 3betaAdiol. When CYP7B1 is inactivated, 3betaAdiol activates estrogen receptors indiscriminately, and the overall effect is prolonged and inappropriate exposure to estrogen.

Androstane-3,17-diol↗

PubMed2005

Estrogen receptor alpha and imprinting of the neonatal mouse ventral prostate by estrogen.

Exposure to estrogen in the neonatal period affects prostatic growth and leads to an increased incidence of prostatic intraepithelial neoplasia in later life. The effects of neonatal estrogen are clearly dependent on estrogen receptor (ER) alpha because they do not occur in ERalpha-knockout mice. Because ERalpha is expressed in the stroma, but not in the epithelium, of the adult ventral prostate, the concept of indirect estrogen effects through stromal signaling has been proposed. Here, we show that during the first 4 weeks of life, there are profound and rapid changes in the ER profile in the mouse ventral prostate. ERalpha is abundant in the stroma during week 1, but by week 2 it is exclusively epithelial, and then by week 4, ERalpha is lost and ERbeta is dominant in the prostatic epithelium. The presence of ERalpha is associated with a high proliferation index, and ERbeta is associated with quiescence. Branching morphogenesis was altered in ERalpha-/-, but not in ERbeta-/-, mice. We conclude that imprinting and branching morphogenesis of the ventral prostate are mediated by estrogen acting directly on epithelial and stromal ERalpha during the first 2 weeks of life.

Animals↗

PubMed2005

The effect of tadalafil on the time to exercise-induced myocardial ischaemia in subjects with coronary artery disease.

OBJECTIVE: To investigate the effect of tadalafil on the time to exercise-induced myocardial ischaemia in subjects with coronary artery disease (CAD). Background CAD and erectile dysfunction (ED) share similar risk factors. It is important to know the cardiovascular effects of tadalafil in patients with CAD during physical exertion that is comparable with sexual activity. METHODS: A randomized, placebo-controlled, double-blind, two-period, crossover study comparing the effects of tadalafil 10 mg and placebo on the time to exercise treadmill test (ETT)-induced myocardial ischaemia in subjects with stable CAD (n = 23; age range: 53-75 years, all exhibited ST-segment depression >1.5 mm at screening ETT at > 5METS). Haemodynamic responses to sublingual nitroglycerin (NTG) were assessed before and after ETT. RESULTS: Compared with placebo, tadalafil did not significantly affect the time to ETT-induced ischaemia (13 min/31 s vs. 13 min/36 s, respectively). Before exercise, NTG evoked decreases in sitting systolic blood pressure (SBP) that were significantly greater when subjects received tadalafil compared with placebo, and after exercise, more subjects experienced a decrease in SBP <85 mmHg in response to NTG after taking tadalafil vs. placebo. When subjects received tadalafil compared with placebo, SBP was lower at rest (-7 mmHg; -12,-2), during ETT (-10 mmHg; -16, -3), and after ETT (-13 mmHg; -19, -7). CONCLUSION: Tadalafil did not significantly alter the time to ETT-induced ischaemia compared with placebo in subjects with CAD. Tadalafil reduced resting and exercise SBP. Due to the potential for hypotension, the concomitant use of nitrates and tadalafil is contraindicated.

Aged↗