dinoprost and Hypertension--Renovascular

The roles of prostanoids in the pathogenesis of cardiovascular diseases and in the development of pathological conditions have been examined using mice lacking the individual, specific prostanoid receptor. Prostaglandin (PG) I2 protected the heart from ischemia-reperfusion injury in a model of acute myocardial infarction. In addition, PGI2 suppressed the development of pressure overload-induced cardiac hypertrophy. Aside from its potent vasodilatory action, PGI2 contributed critically to the development of renovascular hypertension via the activation of the renin-angiotensin-aldosterone system. Thromboxane (TX) A2 and PGF2alpha were found to be the mediators of inflammatory tachycardia under a systemic inflammatory condition induced by lipopolysaccharide. Under a septic condition leading to a vascular hypo-responsive state, TXA2 worked to maintain vascular tone by inhibiting the induction of inducible nitric oxide synthase in vascular smooth muscle cells. Mice lacking the PGE2 receptor subtype EP3 had a bleeding tendency and were resistant to thromboembolism, due to a defective activation of platelets. From these studies, the important and novel roles of prostanoids in the pathogenesis of cardiovascular diseases have been clarified.

Topics: Animals; Blood Platelets; Cardiomegaly; Cardiovascular Diseases; Dinoprost; Epoprostenol; Hemodynamics; Humans; Hypertension, Renovascular; Inflammation Mediators; Mice; Mice, Knockout; Myocardial Reperfusion Injury; Prostaglandins; Receptors, Prostaglandin; Sepsis; Signal Transduction; Tachycardia; Thromboxane A2

Hypertensive patients with renovascular disease (RVD) may be exposed to increased oxidative stress, possibly related to activation of the renin-angiotensin system.. We measured the urinary excretion of 8-iso-prostaglandin (PG) F2alpha and 11-dehydro-thromboxane (TX) B2 as indexes of in vivo lipid peroxidation and platelet activation, respectively, in 25 patients with RVD, 25 patients with essential hypertension, and 25 healthy subjects. Plasma renin activity in peripheral and renal veins, angiotensin II in renal veins, cholesterol, glucose, triglycerides, homocysteine, and antioxidant vitamins A, C, and E were also determined. Patients were also studied 6 months after a technically successful angioplasty of the stenotic renal arteries. Urinary 8-iso-PGF2alpha was significantly higher in patients with RVD (median, 305 pg/mg creatinine; range, 124 to 1224 pg/mg creatinine) than in patients with essential hypertension (median, 176 pg/mg creatinine; range, 48 to 384 pg/mg creatinine) or in healthy subjects (median, 123 pg/mg creatinine; range, 58 to 385 pg/mg creatinine). Urinary 11-dehydro-TXB2 was also significantly higher in RVD patients compared with healthy subjects. In RVD patients, urinary 8-iso-PGF2alpha correlated with 11-dehydro-TXB2 (r(s)=0.48; P<0.05) and renal vein renin (r(s)=0.67; P<0.005) and angiotensin II (r(s)=0.65; P=0.005) ratios. A reduction in 8-iso-PGF2alpha after angioplasty was observed in RVD patients with high baseline levels of lipid peroxidation. Changes in 8-iso-PGF2alpha were related to baseline lipid peroxidation (r(s)=-0.73; P<0.001), renal vein angiotensin II (r(s)=-0.70; P<0.01) and renin (r(s)=-0.63; P<0.05) ratios.. Lipid peroxidation is markedly enhanced in hypertensive patients with RVD and is related to activation of the renin-angiotensin system. Moreover, persistent platelet activation triggered or amplified by bioactive isoprostanes may contribute to the progression of cardiovascular and renal damage in this setting.

Topics: Adolescent; Adult; Aged; Angioplasty; Angiotensin II; Antioxidants; Biomarkers; Blood Glucose; Cholesterol; Cross-Sectional Studies; Dinoprost; F2-Isoprostanes; Female; Homocysteine; Humans; Hypertension; Hypertension, Renovascular; Lipid Peroxidation; Male; Middle Aged; Oxidative Stress; Platelet Activation; Reference Values; Renal Artery Obstruction; Renin; Renin-Angiotensin System; Thromboxane B2; Triglycerides; Vitamins

The impact of coronary artery stenosis (CAS) on renal injury is unknown. Here we tested whether the existence of CAS, regardless of concurrent atherosclerosis, would induce kidney injury and magnify its susceptibility to damage from coexisting hypertension (HT). Pigs (seven each) were assigned to sham, left-circumflex CAS, renovascular HT, and CAS plus HT groups. Cardiac and nonstenotic kidney functions, circulating and renal inflammatory and oxidative markers, and renal and microvascular remodeling were assessed 10 weeks later. Myocardial perfusion declined distal to CAS. Systemic levels of PGF2-α isoprostane, a marker of oxidative stress, increased in CAS and CAS plus HT, whereas single-kidney blood flow responses to acetylcholine were significantly blunted only in CAS plus HT compared with sham, HT, and CAS, indicating renovascular endothelial dysfunction. Tissue expression of inflammatory and oxidative markers were elevated in the CAS pig kidney, and further magnified in CAS plus HT, whereas angiogenic factor expression was decreased. Bendavia, a mitochondria-targeted peptide, decreased oxidative stress and improved renal function and structure in CAS. Furthermore, CAS and HT synergistically amplified glomerulosclerosis and renal fibrosis. Thus, mild myocardial ischemia, independent of systemic atherosclerosis, induced renal injury, possibly mediated by increased oxidative stress. Superimposed HT aggravates renal inflammation and endothelial dysfunction caused by CAS, and synergistically promotes kidney fibrosis, providing impetus to preserve cardiac integrity in order to protect the kidney.

Topics: Acetylcholine; Acute Kidney Injury; Animals; Antioxidants; Arterial Pressure; Coronary Angiography; Coronary Stenosis; Coronary Vessels; Dinoprost; Endothelium; Female; Fibrosis; Glomerular Filtration Rate; Hypertension, Renovascular; Kidney; Oligopeptides; Oxidative Stress; Renal Circulation; Stroke Volume; Swine; Transforming Growth Factor beta1

Abstract Aims: The role of endothelium-derived contracting factors (EDCFs) in regulating renovascular function is yet to be elucidated in renovascular hypertension (RH). The current study investigated whether oxidative stress-dependent cyclooxygenase (COX)-2-derived prostaglandin F(2α) (PGF(2α)) impairs endothelial function in renal arteries of renovascular hypertensive rats (RHR).. Renal hypertension was induced in rats by renal artery stenosis of both kidneys using the 2-kidney 2-clip model. Acute treatment with reactive oxygen species (ROS) scavengers, COX-2 inhibitors, and thromboxane-prostanoid receptor antagonists, but not COX-1 inhibitors, improved endothelium-dependent relaxations and eliminated endothelium-dependent contractions in RHR renal arteries. Five weeks of treatment with celecoxib or tempol reduced blood pressure, increased renal blood flow, and restored endothelial function in RHRs. Increased ROS production in RHR arteries was inhibited by ROS scavengers, but unaffected by COX-2 inhibitors; whereas increased PGF(2α) release was reduced by both ROS scavengers and COX-2 inhibitors. ROS also induced COX-2-dependent contraction in RHR renal arteries, which was accompanied by the release of COX-2-derived PGF(2α). Further, chronic tempol treatment reduced COX-2 and BMP4 upregulation, p38MAPK phosphorylation, and the nitrotyrosine level in RHR renal arteries.. These findings demonstrate the functional importance of oxidative stress, which serves as an initiator of increased COX-2 activity, and that COX-2-derived PGF(2α) plays an important role in mediating endothelial dysfunction in RH.. The current study, thus, suggests that drugs targeting oxidative stress-dependent COX-2-derived PGF(2α) may be useful in the prevention and management of RH. Antioxid. Redox Signal. 16, 363-373.

Topics: Animals; Cyclooxygenase 2; Dinoprost; Endothelium, Vascular; Hypertension, Renovascular; Male; Oxidative Stress; Rats; Rats, Sprague-Dawley

To investigate the acute effects of the superoxide dismutase mimetic 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (tempol) on split kidney function, and renal haemodynamics, in two-kidney, one-clip (2K1C) hypertensive rats.. Three weeks after clipping, or the sham procedure, the effects of intravenous tempol (200 micromol/kg per h) were evaluated on thiobutabarbital anaesthetized Sprague-Dawley rats.. Mean arterial pressure (MAP; 152 +/- 3 versus 122 +/- 3 mmHg, P < 0.001), plasma renin activity (28.7 +/- 3.0 versus 9.5 +/- 0.6 ng/ml per h, P < 0.001) and urinary 8-iso-prostaglandin F2alpha excretion (124 +/- 4 versus 92 +/- 10 pmol/24 h, P = 0.003) were significantly elevated in 2K1C rats compared with sham. Tempol reduced MAP by 15 +/- 1% compared with baseline (P < 0.001) in 2K1C rats. In clipped kidneys, tempol increased the glomerular filtration rate (GFR; +50 +/- 15% from baseline) and the effective renal plasma flow (ERPF; +37 +/- 13%, from baseline), and reduced renal vascular resistance (RVR; -32 +/- 6% from baseline) compared with saline-treated controls (P < 0.05). In non-clipped kidneys, tempol reduced RVR (-24 +/- 5% from baseline) compared with saline-treated controls (P = 0.001). In sham-operated rats, tempol produced a modest reduction in MAP (-8 +/- 2% from baseline, P = 0.003), but did not significantly affect renal haemodynamics or function.. Tempol reduced MAP and RVR in both clipped and non-clipped kidneys of 2K1C hypertensive rats. In addition, tempol increased ERPF and GFR in the clipped kidney. These findings suggest important roles for superoxide in the regulation of renal haemodynamics during the early maintenance phase of renovascular hypertension.

Topics: Animals; Blood Pressure; Cyclic N-Oxides; Dinoprost; Glomerular Filtration Rate; Hypertension, Renovascular; Kidney; Male; Nifedipine; Nitric Oxide; Rats; Rats, Sprague-Dawley; Renal Plasma Flow, Effective; Renin; Spin Labels; Superoxides; Vascular Resistance

Dietary lipids are reported to affect the blood pressure in both humans and experimental animal models with hypertension. In the present study, 2-kidney, 1-clip (2K1C) hypertensive rats were treated with the modified fatty acid tetradecylthioacetic acid (TTA) from the time of clipping or after hypertension was established. TTA treatment attenuated the development of hypertension and reduced established 2K1C hypertension. The mRNA level of renin in the clipped kidney and the plasma renin activity were markedly reduced, and the plasma angiotensin II level tended to decrease after TTA treatment. In addition, TTA reduced the mRNA level of angiotensinogen in white adipose tissue. Prevention of organ damage was demonstrated by normal urinary excretion of protein, maintained serum albumin, lower heart weight, and clearly reduced vascular, glomerular, and tubulointerstitial damage in the nonclipped kidney. Renal function was not affected as estimated by unchanged plasma creatinine. Furthermore, the serum levels of triacylglycerol and cholesterol were reduced by TTA. The serum fatty acid composition was changed, resulting in a favorable increase of oleic acid. However, the levels of all of the omega-3 fatty acids and of linoleic acid were reduced, and no change was seen in the level of arachidonic acid, but the urinary excretion of 8-iso-prostaglandin F2alpha was declined. In conclusion, TTA attenuated the development of hypertension, reduced established hypertension, and prevented the development of organ damage in 2K1C rats, possibly by reducing the amounts of the vasoconstrictors angiotensin II and 8-iso-prostaglandin F2alpha and by inducing a favorable increase of oleic acid in serum.

Topics: Albuminuria; Angiotensin II; Animals; Blood Vessels; Dinoprost; Fatty Acids; Hypertension, Renovascular; Kidney; Liver; Male; Oleic Acid; Proteinuria; Rats; Rats, Wistar; Renin; RNA, Messenger; Sulfides; Vasoconstrictor Agents

The pathophysiological mechanisms responsible for maintenance of chronic renovascular hypertension remain undefined. Excess angiotensin II generation may lead to release of reactive oxygen species and increased vasoconstrictor activity. To examine the potential involvement of oxidation-sensitive mechanisms in the pathophysiology of renovascular hypertension, blood samples were collected and renal blood flow measured with electron-beam computed tomography in pigs 5 and 10 weeks after induction of unilateral renal artery stenosis (n=7) or sham operation (n=7). Five weeks after procedure, plasma renin activity and mean arterial pressure were elevated in hypertensive pigs. Levels of prostaglandin F2alpha (PGF(2alpha))-isoprostanes, vasoconstrictors and markers of oxidative stress, also were significantly increased (157+/-21 versus 99+/-16 pg/mL; P<0.05) and correlated with both plasma renin activity (r=0.83) and arterial pressure (r=0.82). By 10 weeks, plasma renin activity returned to baseline but arterial pressure remained elevated (144+/-10 versus 115+/-5 mm Hg; P:<0.05). Isoprostane levels remained high and still correlated directly with the increase in arterial pressure (r=0.7) but not with plasma renin activity. Stenotic kidney blood flow was decreased at both studies. In shock-frozen cortical tissue, ex vivo endogenous intracellular radical scavengers were significantly decreased in both kidneys. The present study demonstrates, for the first time, that in early renovascular hypertension, an increase in plasma renin activity and arterial pressure is associated with increased systemic oxidative stress. When plasma renin activity later declines, PGF(2alpha)-isoprostanes remain elevated, possibly due to local activation or slow responses to angiotensin II, and may participate in sustenance of arterial pressure. Moreover, oxidation-sensitive mechanisms may influence ischemic and hypertensive parenchymal renal injury.

Topics: Animals; Blood Pressure; Dinoprost; F2-Isoprostanes; Female; Free Radical Scavengers; Hypertension, Renovascular; Kidney Cortex; Oxidative Stress; Renal Artery Obstruction; Renal Circulation; Renin; Swine; Thiobarbituric Acid Reactive Substances

The effect of i.v. bolus administration of PGE2 and PGF2 alpha on carotid blood flow (Q) and mean arterial blood pressure (MAP) was recorded in 21 anaesthetized normotensive control (N) and 12 rats with 1K1C renovascular hypertension (RH). From the measured parameters the regional vascular impedance (PVI) and the change in blood volume were calculated. In normotensive animals both PGs elicited a dose-dependent initial fast increase of Q (threshold dose 0.4 ng/kg) and a decrease of MAP and PVI (threshold dose 0.4 micrograms/kg). Subsequently, Q decreased below the initial level. MAP and PVI remained depressed after E2 but increased after F2 alpha. The time course of the Q and MAP responses was analyzed in more detail at a standard dose 4 micrograms/kg. The average time to peak of the first phase was 12 s and of the second approximately 80 s. The initial levels of Q and MAP were reestablished within 3 to 4 minutes. The total volume of carotid blood flow obtained by planimetric integration was unaltered after F2 alpha but depressed after E2. In hypertensive animals both phases of the response to E2 were significantly retarded and the Q response was nearly abolished. On the other hand, the time course of the reaction to F2 alpha was unchanged but the magnitude of the second pressoric phase was reduced. Thus, the capacity of the carotid vascular bed to dilate remains the same in RH while the ability to constrict is limited. It is concluded that the response of MAP and Q to both PGs are relatively independent.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Blood Pressure; Carotid Arteries; Cerebrovascular Circulation; Dinoprost; Dinoprostone; Hypertension, Renovascular; Male; Rats; Rats, Inbred Strains

A total of 154 patients with essential hypertension (EH), 24 patients with renovascular hypertension (RVH), and 130 Wistar rats were investigated. PGE2 and PGF2 alpha levels were assayed radioimmunologically in renal venous blood and urine of the patients, and the synthesis of PGE2 and PGF2 alpha in renal tissue, renal PGE-9-ketoreductase activity and urinary PG excretion were measured in rats. It was demonstrated that the PGE2 synthesis was depressed in the vascular channel and the renal uropoietic system, with elevated F/E rations, in patients with arterial hypertension. Clinical and experimental studies showed prolonged and excessive salt consumption to be a cause of these changes, rooted in suppressed renal biosynthesis of both PGs and increased conversion of PGE2 to PGF2 alpha. In addition, renal PGE2 inactivation was increased in EH patients, as compared to those with RVH. PGE2 produced in the kidneys of EH patients is always a depressor natriuretic substance, whereas the role of PGF2 alpha is dependent on the water-salt balance. Furosemide and, to a smaller extent, other diuretics, as well as some hypotensive agents, increase urinary PG excretion and depress the F/E ratio in the urine. Repeated PGE2 infusions are shown to enhance the sensitivity of EH patients to hypotensive drugs, so they can be used for the treatment of refractory EH cases.

Topics: Adult; Animals; Blood Pressure; Dinoprost; Dinoprostone; Humans; Hypertension, Renovascular; Kidney; Male; Middle Aged; Muscle, Smooth, Vascular; Natriuresis; Prostaglandins E; Prostaglandins F; Rats; Rats, Inbred Strains; Renal Artery Obstruction; Sodium; Water-Electrolyte Balance

The state of the renal prostaglandins (PG) system was assessed in 54 patients with essential hypertension, stage IB-IIA, as compared to that of patients with symptomatic arterial hypertensions. A decrease in renal PGE2 production, noted in all hypertensive patients and determined on the basis of its diurnal excretion, was particularly pronounced in essential hypertension. Diurnal PGE2 excretion decreased as hypertension progressed in patients with essential hypertension, and renal PGF2 alpha production became prevalent. Renal function is dependent on the level of PG production by the kidney. As renal concentration capacity decreases and renographic findings become less satisfactory, PGE2 excretion decreases as well. Salt loads can bring out functional insufficiency of the renal PG system in essential hypertension, as reflected in a much smaller increase in PGE2 excretion, as compared to the control values, at early stages of salt loading and a considerable increase in PGF2 alpha excretion. In essential hypertension, inadequate renal prostaglandin response to salt loading is, to a certain degree, related to changed renal PGE-9-ketoreductase activity.

Topics: Dinoprost; Dinoprostone; Humans; Hypertension; Hypertension, Renal; Hypertension, Renovascular; Kidney; Prostaglandins; Prostaglandins E; Prostaglandins F; Pyelonephritis; Sodium Chloride

Levels of PGE2, PGF2 alpha and renin activity were measured in renal venous blood of 29 patients with essential hypertension (EH), 23 patients with renovascular hypertension (RVH) and 10 patients with unilateral pyelonephritis and high arterial hypertension. The pattern of change in renal venous PG content was found to be related to the type of renal lesion: the level of PGE2 was lowered and PGF2 alpha/PGF2 ratio increased in the blood outflow from the kidneys of EH patients and from ischemized kidneys of RVH patients as compared to similar parameters in the outflow from contralateral kidneys of patients with RVH and pyelonephritis. Venous levels of both PGs were the highest in pyelonephritis-affected kidneys. Renal venous PG levels go down in all cases as the disease grows older. An acute drop in arterial pressure is accompanied with increased withdrawal of PGF2 alpha from the kidneys and enhanced renin activity in renal veins, while PGE2 drops simultaneously. PGF2 and PGE2 showing different trends of change in response to falling arterial pressure suggests increased transition of PGE2 to PGF2 alpha under the effect of enhanced PG-9-ketodehydrogenase activity. In the abdominal aorta, the scope of drop in arterial pressure correlates to the change in PGF2 alpha level, that is an evidence of PG direct involvement in the autoregulation of renal blood flow.

Topics: Dinoprost; Dinoprostone; Humans; Hypertension; Hypertension, Renal; Hypertension, Renovascular; Kidney; Prostaglandins E; Prostaglandins F; Pyelonephritis; Renal Artery; Renal Veins; Renin

Experiments on anesthesized normotensive rats (NR), spontaneous-hypertensive rats (SHR) and rats with experimental renovascular hypertension (RVR) were made to study the effect of prostaglandins (PG) - PGI2, PGE1, PGF2, and indomethacin on systemic hemodynamics, pressor reaction and cardiac component of the baroreflex. PGI1 (0.015 microgram/kg) PGE1 (5 micrograms/kg) produced marked hypotension which was more remarkable in RVR and SHR than in NR. The hypotensive effect of both PG was determined by peripheral vasodilatation. After administration of PGI2 and PGE1 the baroreflex appreciably rises in hypertensive rats. PGE2 (10 micrograms/kg) elevates arterial blood pressure in NR to a greater degree than in RVR and SHR. Indomethacin (10 mg/kg) raises the pressure by 33% in NR, by 16% in SHR and by 5% in RVR. At the same time baroreflex sensitivity in NR declines by 208%.

Topics: Alprostadil; Animals; Dinoprost; Epoprostenol; Hemodynamics; Hypertension; Hypertension, Renovascular; Indomethacin; Prostaglandin Antagonists; Prostaglandins; Prostaglandins E; Prostaglandins F; Rats; Rats, Inbred Strains

Topics: Animals; Dinoprost; Dinoprostone; Dogs; Hypertension, Renovascular; Kallikreins; Kidney; Kinins; Male; Prostaglandins; Prostaglandins E; Prostaglandins F; Rabbits; Rats; Renin-Angiotensin System; Ureteral Obstruction; Urogenital System