Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An evaluation of 26 surviving outpatient lung transplant recipients at one center showed that 65% (17/26) had significant anemia (hemoglobin < 11 g/L for women, < 14 g/dl for men) at a median follow-up of 13.5 months after transplantation (range, 1-41 months). There were 14 men and 12 women with a mean age of 45.1 years (range, 23.1-66.7 years). Fifteen had a double allograft and 11 had a single allograft. Anemia was normochromic and normocytic/macrocytic with a tendency to anisocytosis, with normal reticulocyte counts. Iron deficiency (transferrin saturation < 20%) was found in 35% (6/17) of anemic patients, and two of them also had ferritin levels < 15 micrograms/L. In addition, vitamin B12 was decreased in 1 patient. Folate levels were all normal. Erythropoietin levels were significantly decreased in anemic lung transplant recipients as compared with nontransplanted iron-deficient anemic patients (median, 1 mU/ml, range 1-41 mU/ml, vs. 53 mU/ml, 15-88 mU/ml; P < 0.05). In nonanemic lung transplant recipients, erythropoietin levels were decreased too, as compared with normal controls (median, 2 mU/ml, range 1-21 mU/ml, vs. 5 mU/ml, 3-32 mU/ml; P < 0.05). Investigation of peripheral stem cells in 9 patients showed normal stimulation of erythroids (burst-forming unit, erythroid; median, 573 cells/ml; range, 128-1898 cells/ml) independent of erythropoietin concentrations. Analysis of putative prognostic factors, such as age, surgical procedure (double vs. single lung allograft), indication for transplantation, time after transplantation, infection status, presence of bronchiolitis obliterans, immunosuppression (+/- azathioprine), serum creatinine, creatinine clearance, hypertension, and arterial partial pressure of oxygen, did not demonstrate any difference in erythropoietin concentrations. Only the sex variable revealed a trend to higher levels in women than in men (median, 4 mU/ml, range 1-41 mU/ml, vs. 1 mU/ml, 1-16 mU/ml; P > 0.05). The causes for low erythropoietin levels are not quite understood yet; however, they offer a rationale for the treatment of chronic anemia with recombinant human erythropoietin.
 ...
PMID:Anemia and erythropoietin levels in lung transplant recipients. 852 18

Erythropoietin (rHuEPO)-induced hypertension represents a clinical problem in hemodialysis units. However, the underlying molecular mechanisms of this side effect are still unclear. In order to assess the potential participation of the endothelial-derived vasoactive factors, nitric oxide and endothelin-1, bovine aortic endothelial cells were incubated in the presence of rHuEPO. The latter (0.1-10 U/ml, 1-24 h) did not modify the synthesis of nitric oxide and endothelin-1 or the expression of nitric oxide synthase and pre-pro-endothelin-1 mRNAs. These results suggest that endothelial-derived vasoactive factors are not a key component in the hypertensive response observed in certain patients after the administration of rHuEPO.
 ...
PMID:Recombinant human erythropoietin does not regulate the expression of endothelin-1 and constitutive nitric oxide synthase in vascular endothelial cells. 878 98

Epoetin beta is a recombinant form of erythropoietin, the hormone responsible for the maintenance of erythropoiesis. The drug binds to and activates receptors on erythroid progenitor cells which then develop into mature erythrocytes. Epoetin beta increases reticulocyte counts, haemoglobin levels and haematocrit in a dose-proportional manner. These changes are accompanied by beneficial cardiovascular effects, including decreased cardiac output, resting heart rate and left ventricular hypertrophy in patients with chronic renal failure (CRF). Increases of 15 to 54% in haemoglobin levels and 17 to 60% in haematocrit were reported after subcutaneous or intravenous epoetin beta therapy in studies of 8 weeks' to 12 months' duration. Two multicentre clinical trials demonstrated clearly the superior efficacy of epoetin beta over placebo in 229 patients with CRF undergoing haemodialysis. Reduction or elimination of transfusion requirements was reported in studies where this parameter was measured. Comparative data indicate that dosage reductions of approximately 30% compared with intravenous therapy are possible when subcutaneous administration of epoetin beta is used. Haematocrit increased more rapidly in 5 multicentre studies in patients who received epoetin beta subcutaneously than in those who received the same dosage intravenously. Correction of anaemia with epoetin beta is associated with significant improvements in quality of life in patients with CRF. Available data indicate greatest cost-effectiveness in patients who are severely incapacitated by anaemia before treatment. The cost of administration of the drug may also be reduced by the use of the subcutaneous route. Hypertension may occur in patients who receive epoetin beta but may be minimised by avoiding rapid increases in haematocrit (> 0.5%/week), and is managed in most cases with control of fluid status and antihypertensive medication. Although clotting of the vascular access has not been conclusively linked to epoetin beta, caution is recommended in patients undergoing haemodialysis. Increased heparinisation is recommended to prevent clotting in dialysis equipment. Epoetin beta is more effective and/or better tolerated than alternative treatments (e.g. androgenic steroids) for anaemia associated with CRF. It also causes significant improvements in quality of life, exercise capacity and overall well-being. Results of clinical studies indicate that subcutaneous administration is desirable where possible in the majority of patients. Thus, epoetin beta has become established as an effective treatment for anaemia associated with CRF.
 ...
PMID:Epoetin beta. A review of its pharmacological properties and clinical use in the management of anaemia associated with chronic renal failure. 880 69

Erythropoietin (EPO) has been reported to induce hypertension in hemodialysis patients with family history of hypertension. In this study, to reveal the mechanism of EPO-induced hypertension, we examined the acute effect of EPO on blood pressure (BP) and renal hemodynamics in genetically hypertensive rats, and we also tested the effect of BQ-123, an endothelin ETA-receptor blocker, on EPO-induced changes in hemodynamics. Male spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY), aged 9-12 wk, were anesthetized, and BP was monitored through the carotid artery. Renal plasma flow (RPF) and glomerular filtration rate (GFR) were measured before and after an intravenous injection of EPO (1,000 U/kg body wt). In another group of SHR, BQ-123 was continuously infused (1.2 mg.kg body wt-1.h-1) during the experiments. The acute injections of EPO increased BP significantly in SHR in a dose-dependent manner, whereas WKY did not show a significant increase in BP after EPO injections. The effect of EPO on BP in SHR was blocked by BQ-123. In SHR, an acute injection of EPO decreased RPF significantly (from 1.78 +/- 0.16 to 1.49 +/- 0.18 ml.min-1.100 g body wt-1, P < 0.05) without a change in GFR, whereas WKY did not show significant changes in either RPF or GFR. The effect of EPO on RPF in SHR was completely blocked by BQ-123 (from 1.92 +/- 0.26 to 1.88 +/- 0.28 ml.min-1.100 g wt-1, NS). EPO caused a significant increase in plasma endothelin ET-1 in SHR (from 2.3 +/- 0.6 to 6.3 +/- 1.6 pg/ml, P < 0.05), but not in WKY. In conclusion, acute administration of EPO raised blood pressure and reduced RPF in SHR, and these vasoconstrictive effects of EPO are mediated via ETA receptors by an enhanced ET-1 release.
 ...
PMID:Endothelin-mediated effect of erythropoietin on blood pressure and renal hemodynamics in hypertensive rats. 896 2

Human recombinant erythropoietin is used to treat chronic anemia in patients with end-stage renal failure. Erythropoietin causes hypertension, and hypertensive encephalopathy has been associated with its use. We describe six dialysis-dependent, chronic renal failure patients who developed hypertension, headache, and seizures while on erythropoietin. Four of the six patients had posterior white matter changes on neuroimaging. The encephalopathy was managed by prompt antihypertensive and anticonvulsant treatment and by discontinuation of erythropoietin. Hypertensive posterior leukoencephalopathy is associated with erythropoietin use.
 ...
PMID:Erythropoietin-associated hypertensive posterior leukoencephalopathy. 971 75

Erythropoietin (EPO) increases Ca2+ influx in vascular smooth muscle cells and acts both as a direct vasoconstrictor and vascular growth factor (that is, angiogenesis). However, the mechanism by which EPO promotes extracellular Ca2+ entry in contractile cells has not been elucidated. In hematopoietic cells, EPO induces tyrosine kinase (TK)-dependent activation of phospholipase C (PLC)-gamma 1 and Ca2+ influx via a voltage-independent Ca2+ conductance. In contractile mesangial cells, we have recently characterized a voltage-independent, 1 pS Ca2+ channel that is dependent on both TK and PLC-gamma 1 activity. Therefore, we examined cultured rat glomerular mesangial cells after timed exposure to recombinant human EPO (20 U/ml). Erythropoietin increased the tyrosine phosphorylation of PLC-gamma 1, promoted membrane complex formation between PLC-gamma 1 and the EPO receptor itself, and raised the levels of intracellular inositol 1,4,5-trisphosphate and intracellular Ca2+. Consistent with our previous studies, 1 pS Ca2+ channel activity was extremely low under basal, unstimulated conditions in cell-attached patches, but was dramatically increased when EPO was present in the patch pipette. Tyrosine kinase inhibition with 100 micron genistein or 1 micron PP1 (Src; selective tyrosine kinase inhibitor) prevented all of these EPO-induced responses. We conclude that: (1) EPO-induced stimulation of 1 pS Ca2+ channels is mediated via a cytosolic Src TK in glomerular mesangial cells. (2) Stimulation of this Ca2(+)-activated, Ca2(+)-permeable channel is dependent on the tyrosine phosphorylation/activation of PLC-gamma 1. (3) This cascade provides a possible mechanism for the vasoconstriction and hypertension observed with clinical EPO use for the treatment of chronic anemias.
 ...
PMID:Erythropoietin receptor-operated Ca2+ channels: activation by phospholipase C-gamma 1. 957 41

Many patients with solid tumours or haematological malignancies develop anaemia, and the use of chemotherapy aggravates this condition. Red blood cell transfusions are often necessary but are associated with many risks, including immunosuppressive effects that may increase the risk of tumour recurrence. Many clinical studies have shown that epoetin (recombinant human erythropoietin) therapy can ameliorate, or even prevent, the anaemia associated with chemotherapy and cancer (including solid tumours as well as multiple myeloma or lymphoma). Response, defined as a significant (>50%) reduction in the rate of transfusions and/or a significant (>2 g/dl) elevation of haemoglobin levels, is usually observed in about 60% of the patients, irrespective of the type of standard chemotherapy given. The decrease in transfusion requirements is the major objective of epoetin therapy, because they are costly, inconvenient and are associated with potential adverse effects. Epoetin therapy also brings about substantial improvements in various indices of quality of life that are proportional to changes in haemoglobin level. However, large dosages of epoetin are generally required and about 40% of patients do not respond even to very high dosages. A number of adverse effects of epoetin therapy have been observed in patients with renal failure. The most prominent include hypertension, headaches, seizures and thrombotic events. These complications can also occur in patients with renal failure who are not receiving epoetin. Their exact incidence has been assessed in placebo-controlled studies, which have demonstrated that there is no increased risk of thrombosis or seizure with epoetin. However, it is now generally accepted that 10 to 20% of haemodialysis patients will experience an elevation of blood pressure because of epoetin and there is no doubt that a rapid elevation of blood pressure may cause generalised seizures. In other settings, including anaemia associated with cancer, very few adverse effects have been attributed to epoetin. However, close monitoring of blood pressure should be implemented in patients with hypertension. There is no evidence that epoetin stimulates tumour growth. With the dosages of epoetin currently used, there is no evidence of stem cell competition, resulting in thrombocytopenia or neutropenia, or of stem cell exhaustion, producing secondary anaemia when treatment is stopped. Epoetin is a remarkably well tolerated drug that offers significant benefits in patients with cancer.
 ...
PMID:A risk-benefit assessment of epoetin in the management of anaemia associated with cancer. 980 42

The target organ failures associated with uremia are most often considered to be caused by processes other than uremia per se. Heart disease, for example, is considered the product of hypertension, lipid abnormalities, and so forth, rather then the uremic state. Erythropoietin deficiency, blood loss, and iron deficiency are believed to cause anemia, rather than the uremic state. Malnutrition is believed to be the product of poor nutrient intake and perhaps nutrient losses, rather than uremia per se. This article reviews evidence suggesting that anemia and malnutrition share a common cause; the acute-phase inflammatory process that is a normal host-defense mechanism. Given the high prevalence of heart disease among patients with end-stage renal disease (ESRD), data indicating activation of the acute-phase process in patients with kidney failure, and emerging evidence that the process has a significant role in the risk for cardiovascular disease among patients without kidney failure, there is a strong likelihood that heart disease will share with anemia and malnutrition the acute-phase state as a contributing cause. Thus, instead of disconnected target organ failures, each with different antecedent causes, we see emerging the likelihood of a unifying pathobiology for uremia. The antecedents of morbidity and mortality appear as a web of organ failures connected by a common pathobiology. Whereas each failure likely has contributing causes other than the acute-phase state, they probably share the state as a causative, contributing, or exacerbating factor.
 ...
PMID:Acute-phase inflammatory process contributes to malnutrition, anemia, and possibly other abnormalities in dialysis patients. 989 76

The number of patients with significant chronic renal failure is expanding rapidly in the United States. All physicians and medical-care providers will have an increasingly important role in the detection and management of renal failure in patients who are not undergoing dialysis. Patients with diabetes or hypertension should be carefully monitored for the development of renal insufficiency by using screening tools such as blood pressure measurement, determination of serum creatinine, urinalysis, and determination of 24-hour urinary microalbuminuria. In order to slow the progression of renal disease, attenuate uremic complications, and prepare patients with renal failure for renal replacement therapy, all medical-care providers should "take care of the BEANS." Blood pressure should be maintained in a target range lower than 130/85 mm Hg, and in many patients, angiotensin-converting enzyme inhibitors may be beneficial. Erythropoietin should be used to maintain the hemoglobin level at 10 to 12 g/dL. Access for long-term dialysis should be created when the serum creatinine value increases above 4.0 mg/dL or the glomerular filtration rate declines below 20 mL/min. Nutritional status must be closely monitored in order to avoid protein malnutrition and to initiate dialysis before the patient's nutritional status has deteriorated. Nutritional care also involves correction of acidosis, prevention and treatment of hyperphosphatemia, and administration of vitamin supplements to provide folic acid. Specialty referral to nephrology should occur when the creatinine level increases above 3.0 mg/dL or when the involvement of a nephrologist would be beneficial for ongoing management of the patient.
 ...
PMID:A practical approach to the management of patients with chronic renal failure. 1008 97

All patients (48) followed by the chronic dialysis program on either peritoneal dialysis or incenter hemodialysis who received epoetin were included in this 1 year retrospective study. Variables evaluated included appropriateness of patient selection, drug dosage, monitoring of epoetin therapy as well as treatment outcome, incidence of side effects, cost versus reimbursement of epoetin, and need for iron supplementation. The target hematocrit of 30 to 36% was reached by 84.6% of patients. The difference between the baseline and treatment hematocrits was statistically significant (p less than 0.01). The average number of transfusions dropped significantly from 0.66 to 0.11 per patient per month (p less than 0.01) and the mean percentage of cytotoxic panel reactivity antibody was also significantly reduced (p less than 0.01) during treatment with epoetin. Serious side effects of epoetin therapy were rare, but four hemodialysis patients experienced five episodes of clotted accesses. The incidence of hypertension requiring addition or change of antihypertensive medication was 17.1%. No seizures were observed during the study period. The results of this study also revealed that more careful attention to iron status was needed during the period of data collection. A nomogram for prediction of iron need based on initial hemoglobin and ferritin levels was also studied and found to be accurate in 87.5% of patients.
 ...
PMID:Drug usage evaluation of epoetin in chronic renal failure. 1012 21


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>