prostaglandin-d2 and Hypertension

Prostaglandin D(2) (PGD(2)) and its metabolites bind to the intracellular PPARs to regulate vasoactive substances involved in vascular remodeling through regulation of mRNAs transcription as well as through receptor-mediated mechanisms. PGD(2) decreases inducible NO, PAI-1, endothelin, and VCAM expression through inhibition to NF kappa B, STAT, or AP-1 transcription factors, which are regulated by cytokines/immune system. Moreover, transfer of L-PGDS (PGD(2) synthase) into the intracellular space of EC or SMC increases intracellular PGD(2), thereby decreasing these substances. PGD(2) attenuates in vivo organ injury mediated by cytokines and the immune system. The pretreatment with PGD(2) attenuates the liver damage and hemodynamic collapse following LPS. Dahl salt-sensitive rats, with decreased PGD(2) in the outer medulla of the kidney, are prone to hypertensive kidney injury. Serum L-PGDS level is increased in renal dysfunction through a decrease in glomerular filtration. L-PGDS in urine may be derived from a failure of tubular reabsorption or from in situ synthesis. Urinary L-PGDS excretion markedly increases in the early stage of kidney injury, and urinary L-PGDS is a useful predictor of the forthcoming renal injury. Indeed, urinary L-PGDS precedes clinically overt proteinuria or other parameters indicating renal dysfunction in hypertension, primary renal diseases, and diabetes in humans. PGD(2)/L-PGDS system is a Cinderella of vascular biology.

Topics: Animals; Diabetes Mellitus; Humans; Hypertension; Intramolecular Oxidoreductases; Kidney Diseases; Lipocalins; Prostaglandin D2; Rats

The clinical use of niacin to treat dyslipidemic conditions is limited by noxious side effects, most commonly facial flushing. In mice, niacin-induced flushing results from COX-1-dependent formation of PGD₂ and PGE₂ followed by COX-2-dependent production of PGE₂. Consistent with this, niacin-induced flushing in humans is attenuated when niacin is combined with an antagonist of the PGD₂ receptor DP1. NSAID-mediated suppression of COX-2-derived PGI₂ has negative cardiovascular consequences, yet little is known about the cardiovascular biology of PGD₂. Here, we show that PGD₂ biosynthesis is augmented during platelet activation in humans and, although vascular expression of DP1 is conserved between humans and mice, platelet DP1 is not present in mice. Despite this, DP1 deletion in mice augmented aneurysm formation and the hypertensive response to Ang II and accelerated atherogenesis and thrombogenesis. Furthermore, COX inhibitors in humans, as well as platelet depletion, COX-1 knockdown, and COX-2 deletion in mice, revealed that niacin evoked platelet COX-1-derived PGD₂ biosynthesis. Finally, ADP-induced spreading on fibrinogen was augmented by niacin in washed human platelets, coincident with increased thromboxane (Tx) formation. However, in platelet-rich plasma, where formation of both Tx and PGD₂ was increased, spreading was not as pronounced and was inhibited by DP1 activation. Thus, PGD₂, like PGI₂, may function as a homeostatic response to thrombogenic and hypertensive stimuli and may have particular relevance as a constraint on platelets during niacin therapy.

Topics: 6-Ketoprostaglandin F1 alpha; Adenosine Diphosphate; Angioplasty, Balloon, Coronary; Animals; Aortic Aneurysm, Abdominal; Apolipoproteins E; Atherosclerosis; Blood Platelets; Carotid Artery Thrombosis; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Double-Blind Method; Endothelium, Vascular; Female; Humans; Hypertension; Male; Membrane Proteins; Mice; Mice, Knockout; Platelet Activation; Platelet Aggregation Inhibitors; Prostaglandin D2; Receptors, G-Protein-Coupled; Receptors, Immunologic; Receptors, LDL; Receptors, Nicotinic; Receptors, Prostaglandin; Thromboxane A2

Topics: Animals; Carotid Arteries; Glutathione Transferase; Hypertension; Intramolecular Oxidoreductases; Lipocalins; Male; Mice; Mice, Knockout; Prostaglandin D2; Sequence Deletion

Prenatal dexamethasone (DEX) exposure, postnatal high-fat (HF) intake, and arachidonic acid pathway are closely related to hypertension. We tested whether a soluble epoxide hydrolase (SEH) inhibitor, 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA) or 15-deoxy-Δ(12,14)-prostagandin J2 (15dPGJ2) therapy can rescue programmed hypertension in the DEX+HF two-hit model. Four groups of Sprague Dawley rats were studied: control, DEX+HF, AUDA, and 15dPGJ2. Dexamethasone (0.1mg/kg body weight) was intraperitoneally administered to pregnant rats from gestational day 16-22. Male offspring received high-fat diet (D12331, Research Diets) from weaning to 4 months of age. In AUDA group, mother rats received 25mg/L in drinking water during lactation. In the 15dPGJ2 group, male offspring received 15dPGJ2 1.5mg/kg BW by subcutaneous injection once daily for 1 week after birth. We found postnatal HF diet aggravated prenatal DEX-induced programmed hypertension, which was similarly prevented by early treatment with AUDA or 15dPGJ2. The beneficial effects of AUDA and 15d-PGJ2 therapy include inhibition of SEH, increases of renal angiotensin converting enzyme-2 (ACE2) and angiotensin II type 2 receptor (AT2R) protein levels, and restoration of nitric oxide bioavailability. Better understanding of the impact of arachidonic acid pathway in the two-hit model will help prevent programmed hypertension in children exposed to corticosteroids and postnatal HF intake.

Topics: Adamantane; Angiotensin-Converting Enzyme 2; Animals; Arachidonic Acid; Dexamethasone; Diet, High-Fat; Epoxide Hydrolases; Female; Humans; Hypertension; Lauric Acids; Nitric Oxide; Peptidyl-Dipeptidase A; Pregnancy; Prenatal Exposure Delayed Effects; Prostaglandin D2; Rats; Receptor, Angiotensin, Type 2

Angiotensin II (Ang II) is a peptide hormone able to elicit a strong production of reactive oxygen species by human neutrophils. In this work, we have addressed whether expression of heme oxygenase-1 (HO-1), an antioxidant enzyme, becomes altered in these cells upon Ang II treatment or under hypertension conditions. In neutrophils from healthy and hypertensive subjects, induction of HO-1 mRNA and protein expression with a parallel increase in enzyme activity took place upon treatment with 15-deoxy-Delta12,14-PGJ2 (15dPGJ2). However, Ang II prevented HO-1 synthesis by normal neutrophils in vitro, and HO-1 expression was depressed in neutrophils from hypertensive patients in comparison with cells from healthy subjects. In addition, Ang II treatment led to a reduced HO-1 enzyme activity to levels similar to those found in neutrophils from hypertensive patients. NO donors reversed the inhibition of 15dPGJ2-dependent HO-1 expression in neutrophils from hypertensive patients, and conversely, inhibition of inducible NO synthase (NOS2) activity counteracted the stimulatory effect of 15dPGJ2 on HO-1 expression in normal human neutrophils. Moreover, Ang II canceled 15dPGJ2-dependent induction of NOS2 mRNA synthesis. Present findings indicate that down-regulation of HO-1 expression in neutrophils from hypertensive subjects is likely exerted through the inhibition of NOS2 expression. Additionally, they underscore the potential usefulness of NO donors as new, therapeutic agents against hypertension.

Topics: Angiotensin II; Cell Culture Techniques; Down-Regulation; Gene Expression Regulation, Enzymologic; Heme Oxygenase-1; Humans; Hypertension; Neutrophils; Nitric Oxide Synthase Type II; Prostaglandin D2; Reference Values

Having previously demonstrated that glucose transporter-4 (GLUT4) expression was reduced in aortas and carotid arteries of deoxycorticosterone acetate (DOCA) salt-hypertensive rats, we hypothesized that troglitazone (TG), through activation of peroxisome proliferator-activated receptor-gamma (PPAR-gamma), would stabilize GLUT4 expression and possibly preserve the differentiated phenotype in vascular smooth muscle cells. In DOCA salt-hypertensive rats treated with TG (100 mg/day), there was a significant (P < 0.001) decrease in systolic blood pressure (BP; 149.9 +/- 4.4 mmHg) compared with the untreated DOCA salt-hypertensive rats (202.2 +/- 10.34 mmHg). Separate trials with rosiglitazone (RS; 3 mg/day) demonstrated a significant (P < 0.001) decrease in BP (DOCA salt, 164.2 +/- 9.8 vs. DOCA-RS, 124.9 +/- 3.7 mmHg) comparable to that with TG. Expression of GLUT4, h-caldesmon, and smooth muscle myosin heavy chain SM2 was significantly decreased in aortas of DOCA salt-hypertensive rats and was reversed by TG to levels similar to those in aortas of sham-treated rats. TG (50 microM) induced GLUT4 and h-caldesmon expression in 24-h culture of explanted carotid arteries of DOCA salt-hypertensive rats, and the endogenous PPAR-gamma ligand 15-deoxy-Delta(12-14)-prostaglandin J(2) (PGJ(2); 20 microM) and TG (50 microM) similarly increased GLUT4, h-caldesmon, and SM2 protein expression in explanted aortas. The expression of activated, phosphorylated Akt was increased by PGJ(2) and TG with no significant effect on total Akt levels. Inhibition of phosphorylated Akt expression using the phosphatidylinositol 3-kinase inhibitor LY-294002 (16 microM) abrogated the increased expression of h-caldesmon and SM2. These data demonstrate that PPAR-gamma agonists maintain or induce expression of markers of the contractile phenotype independently of their effects on hypertension, and that this effect may be mediated through activation of phosphatidylinositol 3-kinase/Akt.

Topics: Animals; Aorta; Arteries; Biomarkers; Blood Pressure; Carotid Arteries; Chromans; Deoxyglucose; Desoxycorticosterone; Glucose Transporter Type 4; Hypertension; Ligands; Male; Monosaccharide Transport Proteins; Muscle Proteins; Muscle, Smooth, Vascular; PPAR gamma; Prostaglandin D2; Rats; Rats, Sprague-Dawley; Rosiglitazone; Sodium Chloride; Thiazolidinediones; Troglitazone

We investigated the eicosanoid synthesis of platelets of Wistar and of Okamoto spontaneously hypertensive rats (SHR), and the effect of captopril in vitro, using [14C]arachidonic acid as a tracer substrate and chromatographic determination. Lipoxygenase activity was elevated, while the formation of cyclooxygenase products was reduced in SHR platelets, compared to those of Wistar rats. This difference might play a role in the pathomechanism of hypertension in SHR. In SHR with lower blood pressure, captopril reduced thromboxane synthesis, while in SHR with higher blood pressure thromboxane synthesis was unchanged, but the synthesis of prostaglandin D2, a potent vasodilator, and of 12-L-hydroxy-5,8,10-heptadecatrienoic acid, a stimulator of endothelial prostacyclin formation, was increased. We may conclude that, in spite of the missing angiotensin converting enzyme in platelets, a direct effect on platelet eicosanoid synthesis could contribute to the blood pressure decreasing effect of captopril.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Arachidonic Acid; Blood Platelets; Blood Pressure; Captopril; Eicosanoids; Fatty Acids, Unsaturated; Hypertension; Lipoxygenase; Male; Prostaglandin D2; Prostaglandin-Endoperoxide Synthases; Rats; Rats, Inbred SHR; Rats, Wistar; Thromboxanes

The effect of treatment for eight weeks with isradipine 1.25 mg twice daily for 4 weeks and thereafter 2.5 mg twice daily for 4 weeks on ex vivo platelet function was investigated in 10 male hypertensive patients, aged 51 (6.1) y. Systolic and diastolic blood pressure, platelet aggregation in response to ADP, serum thromboxane B2 and beta-thromboglobulin levels were significantly decreased at rest before exercise ergometry, during exercise and at rest after exercise. The platelet count, platelet sensitivity and the plasma levels of 6-oxo-prostaglandin F1 alpha were not affected by isradipine. It is concluded that a compound that lowers blood pressure and inhibits platelet activation may be of clinical benefit in the routine treatment of hypertension.

Topics: Analysis of Variance; Antihypertensive Agents; Blood Platelets; Blood Pressure; Calcium Channel Blockers; Dihydropyridines; Epoprostenol; Heart Rate; Humans; Hypertension; Isradipine; Male; Middle Aged; Platelet Aggregation; Prostaglandin D2

The effects of bopindolol, a new nonselective beta-blocking agent, on platelet function have been studied in 10 male hypertensive patients given the drug (1 mg/day) in turn for eight weeks. Bopindolol significantly (p less than 0.01) decreased the bicycle exercise- (1.5 W/kg body weight for 6 minutes) induced increase in platelet aggregation. During bopindolol-treatment both the slope and the height of the platelet aggregation response curve were moderately decreased at rest before exercise and significantly (p less than 0.05) decreased at rest after exercise. During exercise the slope amounted to 75.4 +/- 44 degrees before and to 70.8 +/- 5.3 degrees after therapy (p less than 0.01), the height to 64.0 +/- 11.9% before and to 58.1 +/- 14.7% (p less than 0.05) after therapy. Furthermore, bopindolol significantly increased the exercise-induced decrease in platelet sensitivity to PGI2 (p less than 0.05; IC-50-value: 2.10 +/- 0.47 vs 1.88 +/- 0.31 ng/ml) and PGD2 (p less than 0.05; IC-50-value: (19.88 +/- 2.10 vs 18.57 +/- 1.63 ng/ml). Bopindolol also significantly (p less than 0.05) decreased the exercise-induced elevation in serum-TXB2 (244.9 +/- 35.2 vs 237.3 +/- 27.2 ng/ml) and plasma-TXB2 (15.7 +/- 6.3 vs 13.1 +/- 3.7 pg/ml). The platelet count, the plasma levels of 6-oxo-PGF1 alpha, beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) were not affected by bopindolol. It is concluded that bopindolol favourably affects platelet function, in that it lowers exercise-induced platelet aggregation and TXB2-formation in therapeutical doses and increases platelet sensitivity to antiaggregatory prostaglandins.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 6-Ketoprostaglandin F1 alpha; Adult; Basal Metabolism; beta-Thromboglobulin; Blood Platelets; Epoprostenol; Exercise; Humans; Hypertension; Male; Middle Aged; Pindolol; Platelet Aggregation; Platelet Count; Platelet Factor 4; Prostaglandin D2; Thromboxane B2

To assess the participation of cardiovascular eicosanoids (prostaglandins and thromboxanes) system in the initiation of genetic hypertension, we examined eicosanoids metabolism in the heart, aortic wall and kidney in prehypertensive and hypertensive rat models for spontaneous hypertension (SHR). Vasoconstrictor thromboxane A2 (TXA2) generation in the aortic wall was significantly enhanced by 49% in the prehypertensive and by 18% in the hypertensive SHR when compared to the respective normotensive Wistar-Kyoto rats. Cardiac TXA2 content was significantly increased as well by 14% in the prehypertensive and by 30% in the hypertensive SHR. Moreover, vascular vasodepressor eicosanoids generation was decreased by 10% for PGI2 and by 29% for PGD2 in the prehypertensive SHR although the alterations were eliminated in the hypertensive SHR. In contrast to the cardiovascular eicosanoids system, there was no difference in renocortical TXA2 content in either young or adult SHR while vasodepressor prostaglandins contents were decreased by 29% for PGE2 and by 33% for PGD2 in SHR when they were in the prehypertensive stage. Thus, in the prehypertensive stage of SHR, the cardiovascular eicosanoids system exhibited enhanced vasoconstrictor TXA2 and decreased vasodepressor prostaglandins, thereby producing a vasoconstrictor state. These data indicate that the alterations in the cardiovascular eicosanoids system partially contribute to the initiation of hypertension in SHR.

Topics: Animals; Aorta, Thoracic; Dinoprostone; Epoprostenol; Hypertension; In Vitro Techniques; Kidney; Male; Myocardium; Prostaglandin D2; Prostaglandins; Radioimmunoassay; Rats; Rats, Inbred SHR; Rats, Inbred Strains; Thromboxane A2

Initial experiments demonstrated that the hydantoin prostaglandin derivative, BW 245 C, has potent anti-aggregatory activity on human platelets which may result from its structural similarity with one of the natural prostaglandins. The aim of the present study was to extend this preliminary pharmacological characterization and to determine which, if any, prostaglandin receptor-type is responsible for mediating the biological activity of BW 245 C. A marked species variation was observed in the anti-aggregatory potency of BW 245 C such that in the human (0.36 X PGE1) it was about one hundred times more effective than in the rat (0.003 X PGE1). The relative potencies of PGI2 (ca. 10 X PGE1) and PGE1 were, however, similar in both species. An intravenous bolus injection of 250 micrograms/kg BW 245 C lowered systolic (-23%) and diastolic (-34%) blood pressure in spontaneously hypertensive rats. In radioligand binding studies it showed a high affinity and selectivity for PGD2 platelet receptors, binding to PGI2 or PGE2 receptors was not detectable. Therefore it is concluded that the platelet and cardiovascular actions of BW 245 C are mediated by PGD2 receptors and this accounts for the observed species variation which is a characteristic of this prostaglandin.

Topics: Animals; Blood Platelets; Blood Pressure; Cattle; Female; Heart Rate; Hemodynamics; Humans; Hydantoins; Hypertension; In Vitro Techniques; Male; Platelet Aggregation; Prostaglandin D2; Prostaglandins D; Rats; Receptors, Cell Surface; Receptors, Prostaglandin; Subcellular Fractions; Thromboxanes; Uterus