losartan-potassium and Renal-Artery-Obstruction

Atherosclerotic renal artery stenosis (ARAS) is common in cardiovascular diseases and associated with hypertension, renal dysfunction and/or heart failure. There is a paucity of data about the prevalence and the role of ARAS in the pathophysiology of combined chronic heart failure (CHF) and chronic kidney disease (CKD). We investigated the prevalence in patients with combined CHF/CKD and its association with renal function, cardiac dysfunction and the presence and extent of myocardial fibrosis.. The EPOCARES study (ClinTrialsNCT00356733) investigates the role of erythropoietin in anaemic patients with combined CHF/CKD. Eligible subjects underwent combined cardiac magnetic resonance imaging (cMRI), including late gadolinium enhancement, with magnetic resonance angiography of the renal arteries (MRA).. MR study was performed in 37 patients (median age 74 years, eGFR 37.4 ± 15.6 ml/min, left ventricular ejection fraction (LVEF) 43.3 ± 11.2%), of which 21 (56.8%) had ARAS (defined as stenosis >50%). Of these 21 subjects, 8 (21.6%) had more severe ARAS >70% and 8 (21.6%) had a bilateral ARAS >50% (or previous bilateral PTA). There were no differences in age, NT-proBNP levels and medication profile between patients with ARAS versus those without. Renal function declined with the severity of ARAS (p = 0.03), although this was not significantly different between patients with ARAS versus those without. Diabetes mellitus was more prevalent in patients without ARAS (56.3%) against those with ARAS (23.8%) (p = 0.04). The presence and extent of late gadolinium enhancement, depicting myocardial fibrosis, did not differ (p = 0.80), nor did end diastolic volume (p = 0.60), left ventricular mass index (p = 0.11) or LVEF (p = 0.15). Neither was there a difference in the presence of an ischemic pattern of late enhancement in patients with ARAS versus those without.. ARAS is prevalent in combined CHF/CKD and its severity is associated with a decline in renal function. However, its presence does not correlate with a worse LVEF, a higher left ventricular mass or with the presence and extent of myocardial fibrosis. Further research is required for the role of ARAS in the pathophysiology of combined chronic heart and renal failure.

Topics: Aged; Aged, 80 and over; Analysis of Variance; Atherosclerosis; Cardio-Renal Syndrome; Chi-Square Distribution; Contrast Media; Erythropoietin; Female; Fibrosis; Glomerular Filtration Rate; Heart Failure; Hematinics; Humans; Magnetic Resonance Angiography; Magnetic Resonance Imaging; Male; Meglumine; Middle Aged; Myocardium; Netherlands; Organometallic Compounds; Predictive Value of Tests; Prevalence; Prognosis; Renal Artery; Renal Artery Obstruction; Renal Insufficiency, Chronic; Risk Assessment; Risk Factors; Severity of Illness Index; Stroke Volume; Ventricular Function, Left

Topics: Abdominal Neoplasms; Adolescent; Erythropoietin; Female; Humans; Hypertension, Malignant; Neoplasms, Multiple Primary; Paraganglioma, Extra-Adrenal; Perioperative Care; Polycythemia; Renal Artery Obstruction

To study the role of erythropoietin (Epo) in the pathogenesis of anemia in acute renal failure (ARF), organ Epo mRNA was measured by RNase protection assay in rats with ARF induced by a one hour-occlusion of the left renal artery. Hematocrit was significantly decreased two hours, 24 hours and one week after renal artery occlusion. A significant reduction in serum haptoglobin at two hours and an increase in serum LDH at 24 hours indicated that hemolysis was the likely cause of the initial fall in hematocrit. However, despite the reduced hematocrit, serum Epo concentrations were not significantly different from controls, suggesting that the anemia is maintained because of lack of an appropriate Epo response. Right renal Epo mRNA levels were not significantly different in all groups, but Epo mRNA levels in post-ischemic kidneys were 50 to 67% lower than in contralateral kidneys. However, Epo mRNA in the post-ischemic kidney was increased sixfold by acute hemorrhage, a rise comparable to the ninefold increase observed in contralateral kidneys. In ARF rats exposed to 7.5% O2 for four hours, right kidney Epo mRNA increased 200-fold over normoxic levels, to a value similar to sham-operated hypoxic controls. Epo mRNA in the post-ischemic kidney also increased 200-fold, to 50% of the level in the contralateral kidney. Hepatic Epo mRNA levels were elevated to comparable levels in both groups. In this ARF model, mild anemia is associated with relative Epo deficiency. In the post-ischemic kidney, a substantial capacity for Epo production is retained but the sensitivity of the Epo response to blood oxygen availability is significantly reduced.

Topics: Acute Kidney Injury; Anemia; Animals; Erythropoietin; Hematocrit; Male; Rats; Rats, Wistar; Renal Artery Obstruction; RNA, Messenger

Topics: Animals; Erythropoietin; Female; Humans; Hypertension, Renal; Male; Middle Aged; Oxygen; Rats; Renal Artery Obstruction

Twenty-nine patients with unilateral renal artery stenosis or occlusion were investigated. The veno-arterial gradient (VA-gradient) of erythropoietin (EPO), haemoglobin oxygen saturation and plasma renin activity (PRA) was determined separately in each kidney before and 1 h after angiotensin converting enzyme inhibition (ACE-inhibition). The VA-gradient of EPO and of hemoglobin oxygen saturation were the same in the affected and unaffected kidney during basal conditions. During ACE-inhibition the VA-gradient of EPO disappeared on the affected side but not on the unaffected side. A fall in s-EPO after ACE inhibition was demonstrated in the renal vein on the affected side (-1.4 U l-1, p < 0.01), in the contralateral vein (-0.8 U l-1, p < 0.01) and in the aorta (-0.6 U l-1, p < 0.01). The O2-gradients were reduced on both sides after captopril, from 10.8-7.5% (p < 0.04) on the affected side and from 10.8-9.0% (p < 0.04) on the contralateral. It is suggested that the stimulated renin-angiotensin system may be important for EPO production in the affected kidney in unilateral renal disease.

Topics: Adult; Aged; Captopril; Erythropoietin; Female; Humans; Male; Middle Aged; Oxygen; Renal Artery; Renal Artery Obstruction; Renal Veins

The relationship between the renin-angiotensin system and erythropoietin was studied in twenty patients with renal artery stenosis and hypertension. Ten of the patients had a unilaterally activated renin-angiotensin system (group 1), while ten patients had not (group 2). Plasma erythropoietin was simultaneously measured in a brachial artery and both renal veins before and 5 and 30 min after an intravenous injection of 1.25 mg enalaprilat. The mean (+/- SD) arterial erythropoietin concentration was 27.3 +/- 16.8 mU/ml in group 1 and 14.1 +/- 11.3 mU/ml in group 2 patients (P less than 0.05). There was no significant change after enalaprilat i.v. in either group. The venous erythropoietin concentration in plasma from the stenotic kidney did not differ from that of the contralateral kidney. The higher erythropoietin concentration in group 1 patients may be explained by a systemic stimulatory effect of the renin-angiotensin system on erythropoietin production. As no side-differences were found, renal vein as well as peripheral erythropoietin measurements cannot be used as a tool in the diagnosis of the functional significance of a renal artery stenosis.

Topics: Adult; Aged; Enalaprilat; Erythropoietin; Female; Humans; Hypertension, Renovascular; Male; Middle Aged; Renal Artery Obstruction; Renal Veins; Renin-Angiotensin System

The concentration of erythropoietin (Ep) in blood increases little following a reduction of the renal blood flow (rbf). In the present study we examined whether a reduction of rbf in rats induces a lowering of the renal venous PO2. In addition, the combined effects of reduced rbf and hypobaric hypoxia on the production of Ep were studied. To lower rbf, silver clips with stepwisely reduced inner diameters were applied on both renal arteries. The PO2 of renal venous blood decreased gradually to values below 10 mm Hg, when rbf was reduced from 80 to 10% of normal. Under these conditions plasma Ep increased only moderately from 20 +/- 6 to 69 +/- 24 mU/ml within 18-20 h. However, plasma Ep of rats exposed to hypobaric hypoxia (stimulated altitude of 6000 m for 18-20 h) was 431 +/- 68 mU/ml, when rbf was 100-80% of normal, compared to 931 +/- 91 mU/ml, when rbf was reduced to 40-10%. Thus, a reduction of the blood flow to the kidney appears to be no major stimulus for the production of Ep, even when the PO2 in the kidney becomes very low. However, plasma levels of Ep increase markedly, when the whole body O2 offer is lowered. These results support the view that Ep production is not only dependent on the PO2 in the kidney but also under the control of extrarenal O2 sensitive mechanisms. For example, the hypothalamic-hypophyseal system is thought to influence the production of Ep.

Topics: Animals; Biological Assay; Blood Flow Velocity; Erythropoietin; Kidney; Male; Oxygen Consumption; Partial Pressure; Rats; Rats, Inbred Strains; Renal Artery Obstruction

It is generally assumed that the O2 supply to the kidneys is the major determinant of the synthesis of erythropoietin (Ep). In the present study, the O2 supply of the kidneys of rats was lowered by the reduction of renal blood flow (rbf). Plasma Ep was determined after about 18 h of bilateral application of Goldblatt clips with graded inner diameters. The results were compared to findings in anemic rats, in which the systemic O2 supply was lowered by exchange transfusion of blood with plasma. We found a linear correlation between Ep levels in plasma and the degree of reduction of rbf. However, there was an exponential relationship between Ep levels and the concentration of hemoglobin in blood. In addition, the elevation of plasma Ep was only moderate, when rbf was reduced (maximum 0.07 IU Ep/ml plasma). The increase in Ep concentration was much more pronounced in anemia (up to about 7 IU Ep/ml plasma). From these results it may be concluded that decreasing oxygen supply to the kidney through reduction in renal blood flow (ischemic hypoxia) is less effective in increasing erythropoietin production than reducing the hemoglobin concentration (anemic hypoxia). The possibility must be considered that the increase in renal production of erythropoietin due to anemic hypoxia is triggered by one or more extrarenal signals.

Topics: Anemia; Animals; Erythropoietin; Kidney; Male; Rats; Rats, Inbred Strains; Renal Artery Obstruction

Topics: Adult; Erythropoietin; Humans; Male; Polycythemia; Renal Artery Obstruction

We present here results of studies on four patients (three men, one woman) who had had cadaver renal transplants and in whom renal artery stenosis and hypertension developed. Erythropoietin-dependent erythrocytosis developed in association with these changes in the three men. All patients had stable renal function and the hypertension was well controlled. Absolute erythrocytosis thought to be secondary to local renal hypoxia due to decreased renal blood flow developed in two of the men. Erythrocytosis developed in the other man but his RBC mass was at the upper limit of normal. In these patients, we suspect that the erythropoietin-dependent erythrocytosis is secondary to intrarenal hypoxia due to renal artery stenosis. Erythrocytosis or elevated erythropoietin levels failed to develop in the woman despite severe renal artery stenosis. Possible reasons for this discrepancy are discussed.

Topics: Adult; Cadaver; Creatinine; Erythropoietin; Female; Hematocrit; Humans; Kidney Transplantation; Male; Polycythemia; Postoperative Complications; Renal Artery Obstruction; Renin; Transplantation, Homologous

1. Issuing from the clinical method of proceeding in side-separated diagnosis of the renal function under theoretical aspect a survey orientation for the renal global function is tried. 2. The method orientation is done according to semiquantitative and quantitative valuation. The isotope and contrast remedy urography, the functional tests after Howard, Rapoport and Stamey, the conventional side-separated estimation of the clearance, the isotope sequence scintigraphy as well as the diagnostics of the renal and intrarenal haemodynamics (renin determination, measuring of the renal plasma flow by means of PAH and other indicators [133-xenon-wash-our-technique]). 3. Finally a valuation of the method concerning the side-separated diagnostics of the renal elimination function as well as of the stenosis of the renal arteries is done taking into consideration the performability of the investigation methods in the clinic.

Topics: Acid-Base Equilibrium; Erythropoietin; Humans; Kidney; Kidney Function Tests; Radionuclide Imaging; Renal Artery Obstruction; Renin; Urography

To evaluate the effect of prostaglandin inhibition on the renal blood flow of the ischemic kidney, we administered indomethacin to 10 anesthetized dogs with renal artery stenosis and contralateral nephrectomy. Following the operation to produce renal ischemia, there was an increase of blood pressure associated with an increase of renin and the prostaglandins F1 (PGF1), and E (PGE). The administration of indomethacin to the intact, normotensive animals caused the anticipated decrease of prostaglandin E, renin, and renal blood flow. However, in the hypertensive dogs, indomethacin caused a paradoxical 45 per cent increase in the renal blood flow, despite a 44 per cent decrease of prostaglandin E. PGF1, PGE, renin, and erythropoietin exhibited the anticipated decreased levels. The study suggests that prostaglandins may not be the sole important factor in the regulation of renal blood flow in the presence of ischemia. Other important factors likely include the renin-sensitive angiotensin, the adrenergic, and the kallikrein-kinin systems.

Topics: Animals; Blood Pressure; Dogs; Erythropoietin; Female; Hypertension; Indomethacin; Ischemia; Kidney; Male; Nephrectomy; Prostaglandins E; Prostaglandins F; Regional Blood Flow; Renal Artery Obstruction; Renin

A case of erythrocytosis with increased plasma erythropoietin level was reported. Peripheral leucocytes and thrombocytes were normal. No splenomegaly was detected. Studies to find underlying disorders causing increased plasma erythropoietin level and erythrocytosis revealed no abnormalities except for the thickened and tortuous interlobular and afferent arteries in the kidney. This change was suggested as the cause of erythrocytosis found in this case.

Topics: Adult; Erythropoietin; Humans; Kidney; Male; Polycythemia; Renal Artery Obstruction

Spontaneously flowing fistulae were established in the efferent lymphatics of popliteal, prescapular and prefemoral nodes and lumbar trunk or in the afferent lymphatics draining the kidney and liver of sheep. Lymph was collected from these sites over various time intervals and assayed for erythropoietin (Ep) content. The objective of the study was to establish the anatomic site(s) of Ep production. Normal lymph did not contain detectable titers of Ep, nor did renal lymph or blood plasma from a sheep systematically treated with cobaltous chloride. Renal lymph did contain measurable levels of Ep following renal artery constriction, unilateral hydronephrosis or phenylhydrazine-induced hemolytic anemia. Phenylhydrazine treatment also produced elevated Ep levels in lymph from the liver but not in lymph efferent from either popliteal or prescapular nodes. These results indicate that Ep is generated primarily in the kidney and that the liver may be an extrarenal source of the hormone. The surgical techniques used in this study offer distinct advantages in examining the composition and physiology of lymph in sheep.

Topics: Anemia, Hemolytic; Animals; Cobalt; Erythropoietin; Female; Hydronephrosis; Kidney; Liver; Lymph; Mice; Phenylhydrazines; Renal Artery Obstruction; Sheep

Topics: Animals; Carcinoma, Hepatocellular; Erythropoietin; Hepatectomy; Humans; Kidney; Liver; Liver Neoplasms; Nephrectomy; Rats; Renal Artery Obstruction

Topics: Animals; Chemoreceptor Cells; Erythropoietin; Hypoxia; Kidney; Male; Rabbits; Rats; Renal Artery Obstruction

Topics: Animals; Arteriovenous Shunt, Surgical; Biological Assay; Blood Cell Count; Dogs; Erythropoietin; Female; Hemoglobins; Hypoxia; Iron Isotopes; Ischemia; Kidney; Kidney Function Tests; Ligation; Male; Nephrectomy; Pulmonary Artery; Pulmonary Veins; Renal Artery; Renal Artery Obstruction; Renin

Topics: Animals; Erythropoiesis; Erythropoietin; Hematocrit; Hemoglobinometry; Hydronephrosis; Ischemia; Kidney Diseases; Male; Rabbits; Renal Artery Obstruction

Topics: Animals; Atmospheric Pressure; Blood Cell Count; Blood Pressure; Blood Volume; Carotid Arteries; Chemoreceptor Cells; Erythrocyte Count; Erythropoiesis; Erythropoietin; Hematocrit; Hemoglobinometry; Hemoglobins; Hypoxia; Ischemia; Kidney Diseases; Male; Rabbits; Rats; Renal Artery Obstruction; Time Factors; Urea

Topics: Angiotensin II; Animals; Biological Assay; Blood Flow Velocity; Blood Pressure Determination; Dogs; Erythrocytes; Erythropoiesis; Erythropoietin; Fasting; Female; Hematocrit; Infusions, Parenteral; Iron; Iron Isotopes; Male; Mice; Polycythemia; Rats; Renal Artery Obstruction

In 123 patients with arterial hypertension the haemoglobin values were determined before and during long-term antihypertensive drug treatment. The haemoglobin values found before treatment did not differ from those found in the normal population. In both sexes the haemoglobin values showed a significant increase after prolonged treatment. In males the average values rose from 15.1 to 16.7 g./100 ml., and in females from 13.96 to 14.82 g./100 ml. The increase in the haemoglobin concentration does not seem to be clearly correlated to the duration of treatment or to the decrease produced in mean blood pressure. On the other hand, the increase in haemoglobin depended to some extent on the nature of treatment. Diuretics alone resulted in a moderate increase only, whereas diuretics in combination with other antihypertensive drugs produced a more pronounced increase in haemoglobin values.

Topics: Adult; Aged; Antihypertensive Agents; Creatinine; Diuretics; Erythropoietin; Female; Glomerulonephritis; Hematocrit; Hemoglobinometry; Humans; Hydrochlorothiazide; Male; Methyldopa; Middle Aged; Polycythemia; Polythiazide; Pyelonephritis; Renal Artery Obstruction; Triamterene

Topics: Aortography; Erythropoietin; Hematocrit; Humans; Hypertension, Renal; Male; Middle Aged; Polycythemia; Renal Artery Obstruction; Urography

Topics: Animals; Blood Flow Velocity; Dogs; Erythropoietin; Female; Glycolysis; Humans; Hypertension, Renal; Kidney; Male; Oxygen Consumption; Regional Blood Flow; Renal Artery Obstruction

Topics: Animals; Erythropoietin; Female; Hematocrit; Hemorrhage; Hydronephrosis; Hypotension; Iron Isotopes; Kidney Diseases; Male; Primates; Renal Artery Obstruction; Uremia

Topics: Animals; Dogs; Erythropoietin; Hemodynamics; Hypertension, Renal; Juxtaglomerular Apparatus; Kidney; Renal Artery Obstruction

Topics: Animals; Blood Urea Nitrogen; Epoetin Alfa; Erythropoietin; Hypoxia; Iron Isotopes; Kidney Diseases; Mice; Pathology; Polycythemia; Rabbits; Radiometry; Renal Artery Obstruction; Research; Reticulocytes; Urea

Topics: Animals; Bone Marrow Diseases; Chromium Isotopes; Constriction; Epoetin Alfa; Erythrocyte Count; Erythropoietin; Hemoglobinometry; Juxtaglomerular Apparatus; Kidney; Lagomorpha; Pathology; Polycythemia; Rabbits; Renal Artery; Renal Artery Obstruction; Research; Urine

Topics: Animals; Constriction; Epoetin Alfa; Erythropoietin; Histocytochemistry; Immunoelectrophoresis; Iron Isotopes; Kidney; Lagomorpha; Rabbits; Renal Artery; Renal Artery Obstruction; Research; Tissue Extracts; Urine

Topics: Animals; Blood Volume; Epoetin Alfa; Erythrocyte Count; Erythropoietin; Hemoglobinometry; Hydronephrosis; Kidney Diseases; Physiology; Polycythemia; Rabbits; Renal Artery Obstruction; Renal Veins; Research