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Query: UMLS:C0085580 (essential hypertension)
 14,686 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasma activities of renin and erythropoietin were determined in the renal veins of the right and left kidneys of hypertensive patients. The patients were divided into the following groups either according to the origin of the hypertension (group 1: control for essential hypertension, group 2: renovascular hypertension) or according to the hormone levels (group 3: renin activity exceeding 10 ng/litre in at least one of the renal veins and group 4: erythropoietin activity higher than 4% 59Fe incorporation in at least one of the renal veins). In groups 1, 2 and 3 a statistically significant difference in renin activity was found between the kidney with the higher renin activity and that with the lower activity. However, in group 4, the side, which showed elevated erythropoietin values also had higher renin activity as compared to the essential hypertensive group. Erythropoietin activity probably does not parallel the increased renin activity found in renovascular hypertension or in some cases of non-renovascular hypertension. However, in several cases of renal vascular alterations, both systems can be activated simultaneously.
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PMID:Activity of erythropoietin and renin in renal venous blood of hypertensive patients. 95 3

The effects of erythropoietin (EPO) on cytosolic free calcium concentration ([Ca2+]i) in platelets of 20 essential hypertensive patients (HT) and of 25 normotensive subjects (NT) were investigated using the fura2 technique. In resting platelets [Ca2+]i were not significantly higher in HT compared to NT (74.3 +/- 7.8 nM vs 59.8 +/- 7.0 nM, mean +/- SEM). Addition of EPO significantly increased [Ca2+]i in HT compared to NT (13.8 +/- 5.3 nM vs 0.9 +/- 1.9 nM, p less than 0.01). EPO increased the amount of calcium in intracellular stores. This was confirmed independently using thrombin-induced changes of [Ca2+]i in a calcium-free medium and using chlorotetracycline as a marker of stored calcium. After preincubation with EPO thrombin-induced changes of [Ca2+]i were significantly lower in HT compared to NT (306.1 +/- 30.0 nM vs 407.7 +/- 35.7 nM, p less than 0.05). In a calcium-free medium after preincubation with EPO thrombin-induced changes of [Ca2+]i were significantly lower in HT compared to NT (54.7 +/- 11.8 nM vs 100.9 +/- 10.5 nM, p less than 0.05) indicating lower storage capacity in HT. It is concluded that elevated response to EPO may provide a powerful tool to evaluate diagnosis and underlying pathophysiological mechanisms in essential hypertension.
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PMID:Erythropoietin induced transmembrane calcium influx in essential hypertension. 161 80

Alterations in the renal metabolism and/or actions of endothelin-1 (ET-1) may be involved in the pathogenesis and maintenance of essential and renal parenchymal hypertension. ET-1 has the potential to modify a broad range of renal functions involved in controlling systemic blood pressure. First, the kidney clears a large percentage of ET-1 from the blood; decreased renal ET-1 clearance may contribute to hypertension occurring in the setting of chronic renal failure. Second, ET-1 potently constricts the renal vasculature resulting in increased fluid retention and possibly contributing to glomerular sclerosis; enhanced renal vascular and glomerular ET-1 production and target cell actions may play a role in essential hypertension or hypertension accompanying chronic renal failure, cyclosporine administration, or erythropoietin therapy. Lastly, ET-1 is also an autocrine inhibitor of collecting duct sodium and water reabsorption; reduced nephron ET-1 production may result in fluid retention in essential hypertension. Determination of the true role that ET-1 plays in the pathogenesis of the varied forms of hypertension awaits the development of safe, potent, and specific endothelin antagonists.
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PMID:Role of intrarenal endothelin in the generation and maintenance of hypertension. 756 83

This small open study in elderly patients with essential hypertension investigated the effects of the angiotensin II AT1 receptor antagonist on red blood cell haematology and haemorheology. Administration of losartan over a 1-year period was not associated with a significant reduction in haemoglobin or plasma erythropoietin (EPO) concentrations and haemorheological indices remained unchanged. These findings are in contrast to similar studies with angiotensin-converting enzyme (ACE) inhibitors that have shown a significant reduction in erythropoietic activity and a decrease in blood viscosity. Our results indicate therefore that blocking the angiotensin II AT1 receptor does not affect erythropoiesis. Losartan has no adverse haemorheological effects and was associated with a small and statistically insignificant decrease in blood viscosity.
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PMID:Effect of losartan on haematology and haemorheology in elderly patients with essential hypertension: a pilot study. 759 4

We assessed the influence of hyperoxemia on erythropoietin secretion in patients with various etiological forms of arterial hypertension (essential, n = 15; renoparenchymal, n = 16; renovascular, n = 15) and in 15 healthy subjects. On the first day of the study, blood was withdrawn at 1-hour intervals for the estimation of erythropoietin during a total of 6 hours and at 2-hour intervals for the assessment of PO2. Three days later the same parameters were assessed again at identical time intervals, but the subjects were breathing pure oxygen during the first 2 hours. Breathing with pure oxygen resulted in a significant increase of blood PO2 (184.85 +/- 4.47 versus 85.92 +/- 2.28 in essential, 185.21 +/- 5.52 versus 84.55 +/- 3.04 in renoparenchymal, and 181.7 +/- 3.14 versus 87.49 +/- 2.25 in renovascular hypertension groups and 189.84 +/- 5.2 versus 85.89 +/- 1.73 mm Hg in healthy subjects; P < .001 in all groups). Baseline plasma erythropoietin was not different among the groups (29.33 +/- 4.14 in essential, 24.56 +/- 3.09 in renoparenchymal, and 27.77 +/- 3.29 in renovascular hypertension groups and 24.23 +/- 2.70 mU/mL in the control group). The pattern of erythropoietin decline was different in the groups of hypertensive patients. In patients with essential hypertension, unlike in healthy subjects and patients with other etiological forms of arterial hypertension, only a very short-term suppression of erythropoietin levels was observed during hyperoxemia. No significant changes in blood pressure during breathing with pure oxygen were found in any of the studied groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of isobaric hyperoxemia on erythropoietin secretion in hypertensive patients. 808 16

Recent studies suggest the existence of a relationship between the renin-angiotensin system and erythropoietin (EPO) secretion. It has been studied whether patients with various forms of arterial hypertension (essential, renal, renovascular, in the course of arteritis) differ with respect to EPO secretion and whether EPO serum levels are related to renin response induced by dietary sodium restriction to 10-20 mmol Na/24 h for 3 days and upright body position for 3 h. Patients with different forms of hypertension and normal renal excretory function and healthy subjects did not differ in hematocrit value, markers of iron metabolism, and EPO secretion except for patients with arteritis who had higher ferritin values. In these patients a positive correlation between EPO levels and hematocrit values suggests the existence of an altered regulation of EPO secretion. In essential hypertension a negative correlation found between changes in EPO and PRA levels in response to sodium restriction and upright body position may also reflect an altered regulation of both EPO and renin production.
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PMID:Influence of the renin-angiotensin system stimulation on erythropoietin production in patients with various forms of arterial hypertension. 830 4

Regulation of renal erythropoietin (EPO) production has not yet been clearly established in physiologic as well as in pathologic conditions. Recent studies suggest a possible role for renin-angiotensin system in control of EPO production. An elevation in blood pressure occurs commonly in patients with various forms of anaemia treated with recombinant human EPO. Furthermore it has been found that EPO can alter secretion of hormones engaged in regulation of intravascular fluid volume and vascular resistance. The aim of this study was to determine whether patients with essential hypertension (EH) and healthy subjects differ in EPO secretion and whether EPO serum level is related to renin response to dietary sodium restriction and upright position of the body. 63 patients with EH and 12 healthy subjects were investigated. Patients with EH were divided into subgroups on the following criteria: renin response to dietary sodium restriction and upright position of the body. 63 patients with EH and 12 healthy subjects were investigated. Patients with EH were divided into subgroups on the following criteria: renin response to dietary sodium restriction and upright position of the body and severity of existing hypertension. In all subjects haematocrit value, haemoglobin concentration, erythrocyte count, sodium, potassium, creatinine, iron, ferritin serum levels, total iron binding capacity, plasma renin activity (PRA), erythropoietin serum level and mean arterial blood pressure (MAP) were measured in basic conditions (normal sodium diet). Additionally PRA, EPO and MAP were measured after dietary sodium restriction for three days and upright position of the body for three hours.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Relation between erythropoietin production and plasma renin activity in patients with essential hypertension]. 841 37

Patients on maintenance hemodialysis with a family history of essential hypertension are at higher risk for increased arterial blood pressure when treated with erythropoietin than patients without family history. This study was performed to elucidate the role of endogenous erythropoietin in essential hypertension. We conducted a study in 42 untreated patients (mean age, 51 +/- 9 years) with essential hypertension World Health Organization stages I or II. Ambulatory 24-hour blood pressure (Spacelab 90207), cardiac output (2D guided M-mode echocardiography and CW Doppler sonography), renal hemodynamics (para-aminohippurate and inulin clearance), and endogenous erythropoietin (radioimmunoassay) together with erythrocyte count, hemoglobin, and hematocrit were measured in parallel. Mean 24-hour systolic blood pressure was 145 +/- 13 mm Hg, and mean diastolic blood pressure was 93 +/- 8 mm Hg. The average erythropoietin concentration was 15.3 +/- 3.7 mU/mL and within the normal range. We found that the higher erythropoietin concentrations, the more elevated was both 24-hour ambulatory systolic (r = 0.51, P < 0.005) and diastolic blood pressure (r = 0.49, P < 0.005). Also, the concentration of endogenous erythropoietin was correlated with total peripheral resistance as noninvasively determined by echocardiographic and Doppler sonographic measurements (r = 0.40, P < 0.02 and r = 0.49, P < 0.02, respectively). With increasing erythropoietin concentrations, renal plasma flow and renal blood flow were found to be progressively reduced (r = -0.32, P < 0.05 and r = -0.35, P < 0.05, respectively) and renal vascular resistance increased (r = 0.41, P < 0.01). Neither hematocrit nor hemoglobin nor erythrocyte count were related to endogenous erythropoietin concentrations. In human essential hypertension, the level of arterial blood pressure is related to endogenous erythropoietin, which is hemodynamically mediated by an increase of total peripheral resistance. Because erythropoietin has shown proliferative and vasoconstricting effects on the endothelium in experimental studies, we suggest that endogenous erythropoietin might be an aggravating or even a promoting factor in the pathogenesis of essential hypertension.
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PMID:Endogenous erythropoietin correlates with blood pressure in essential hypertension. 904 Dec 13

The genes that determine the baseline hematocrit level in humans and experimental animals are unknown. The spontaneously hypertensive rat (SHR), the most widely used animal model of human essential hypertension, exhibits an increased hematocrit when compared with the normotensive Brown Norway (BN-Lx) strain (0.54 +/- 0.02 vs. 0.44 +/- 0.02, p < 0.01). Distribution of hematocrit values among recombinant inbred (RI) strains derived from SHR and BN-Lx progenitors was continuous, which suggests a polygenic mode of inheritance. The narrow heritability of the hematocrit was estimated to be 0.32. The Eno2 marker on Chromosome (Chr) 4 showed the strongest association (p < 0.0001) with the observed variability of hematocrit among RI strains. The erythropoietin (Epo) gene, originally reported to be syntenic with Eno2, has been mapped to Chr 12, thus excluding it as a potential candidate gene for the increased hematocrit in the SHR. The current linkage data extend homologies between rat, mouse, and human chromosomes.
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PMID:Mapping genes controlling hematocrit in the spontaneously hypertensive rat. 916 79

This paper is a summary of results obtained in our studies on leptinemia in patients with chronic renal failure treated with recombinant human erythropoietin (rHuEPO), in kidney transplant patients, in patients with essential hypertension, and in pregnant women with preeclampsia. In this study, we found that rHuEPO treatment has a suppressive effect on leptinemia in patients with endstage renal failure. These results suggest that the appetite stimulating effect of rHuEPO may be mediated by a reduction of leptin synthesis and release. At the early stage of successful kidney transplantation, a significant decline of leptinemia was noticed, which was not related either to the excretory function of the graft or the kind and dose of immunosuppressants. In kidney transplant patients with grafts functioning well for 2.5 years, significantly elevated leptinemia was found. From these results, we may conclude that factors other than the excretory function of the graft and the kind and dosage of immunosuppressants may be involved in the pathogenesis of abnormal leptinemia in these patients. Both in normotensive subjects and patients with essential hypertension, a positive correlation was found between leptinemia and mean blood pressure, suggesting that leptin may be involved in the regulation of blood pressure. Both healthy and preeclamptic pregnant women show higher leptinemia than nonpregnant women. In preeclamptic women, leptin levels in maternal vein blood, umbilical cord blood, and amniotic fluid were significantly higher than respective values found in healthy pregnant women. In contrast to healthy pregnant and nonpregnant women, in women with preeclampsia, no correlation was found between the body mass index (BMI) and leptinemia. In preeclamptic women the abnormally elevated leptinemia was not related to blood pressure. Finally, no correlation was found between leptinemia in maternal and umbilical cord blood. From these studies, it follows that the elucidation of abnormal leptin secretion in the pathogenesis of preeclampsia needs further study.
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PMID:Pathophysiological role of leptin in patients with chronic renal failure, in kidney transplant patients, in patients with essential hypertension, and in pregnant women with preeclampsia. 995 Jan 82


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