Endogenous ouabain and cardiomyopathy in dialysis patients.

BACKGROUND AND METHODS: Endogenous ouabain (EO) is markedly raised in patients with chronic renal failure. As high EO induces myocardial cell hypertrophy in vitro and it is associated with left ventricular hypertrophy (LVH) in essential hypertensives and in patients with heart failure we investigated the relationship between plasma EO and LV mass and geometry in 156 end-stage renal disease (ESRD) patients. EO was measured by a specific radioimmunoassay and by mass spectrometry. RESULTS: On univariate analysis, plasma EO was directly related to LV mass (r = 0.26, P = 0.001) and LV end diastolic volume (r = 0.25, P = 0.002) and these relationships held true in multiple linear regression models including a series of potential confounders. Patients with eccentric LVH (n = 41, i.e. 26%) had the highest plasma levels of EO when compared to patients with other patterns of LV geometry (P = 0.001). Furthermore, plasma EO had diagnostic value for eccentric LVH because the area under the corresponding ROC curve (68%) was significantly greater (P = 0.002) than the threshold of diagnostic indifference. In this analysis, the sensitivity was 91% and the specificity was 36%. The positive predictive value was 33% but EO had a remarkably high negative predictive value (92%) for the exclusion of eccentric hypertrophy. CONCLUSIONS: In ESRD patients, plasma EO is independently associated with LV mass, LV volume and eccentric LVH. The results of this study are compatible with the hypothesis that EO is involved in alterations of LV mass in ESRD.

Circulating E-selectin as a risk marker in patients with end-stage renal disease.

BACKGROUND: E-selectin is a key adhesion molecule which plays a fundamental role in endothelial progenitor cell-dependent reparative mechanisms in experimental ischaemia and it serves to anchor leucocytes to the endothelium in inflammatory processes. Inflammation is one of the strongest risk factors for death and cardiovascular (CV) events in end-stage renal disease (ESRD). OBJECTIVE: The objective of the current study was to evaluate whether E-selectin is a useful biomarker of clinical outcome in ESRD patients. We tested the prediction power of circulating E-selectin for mortality and CV events in a cohort of 265 ESRD patients. RESULTS: During the follow-up, 59 patients died and 58 had CV events. All-cause mortality was inversely related to serum E-selectin, the risk of death being the lowest in patients in the third E-selectin tertile (HR: 1, reference group), intermediate in those in the second tertile (HR: 1.30) and the highest in patients in the first tertile (HR: 2.02, P = 0.01). Similarly, the risk of fatal and nonfatal CV events followed an inverse pattern being lowest in the third tertile (reference group) and highest in the first tertile (HR: 1.73, P = 0.03). The prediction power of E-selectin for death and CV events was confirmed in a Cox regression analysis where E-selectin emerged as an inverse predictor of these outcomes, particularly so in patients with severe inflammation. CONCLUSIONS: These data are in keeping with the hypothesis that in systemic inflammation altered E-selectin shedding may play a role in arterial damage and implicates this adhesion molecule in atherosclerotic complications in a high-risk condition like ESRD.

Fibrinogen, mortality and incident cardiovascular complications in end-stage renal failure.

OBJECTIVE: Fibrinogen is an established predictor of cardiovascular events in the general population but the relationship between fibrinogen, mortality and incident cardiovascular complications has been very little investigated in patients with end-stage renal disease (ESRD). DESIGN AND SUBJECTS: We investigated the relationship between fibrinogen and all cause mortality and cardiovascular outcomes in a prospective cohort study in 192 patients on chronic haemodialysis treatment (follow-up: 34 +/- 16 months). RESULTS: Fibrinogen was significantly higher in patients who died during the follow-up than in those who survived. Similarly, fibrinogen was higher in patients who had fatal or nonfatal cardiovascular events than in event free patients. On multivariate Cox regression analysis fibrinogen was an independent predictor of survival [hazard ratio (1 g x L(-1) increase in plasma fibrinogen): 1.19, 95% confidence interval (CI): 1.05-1.35, P = 0.006] and a highly significant (P = 0.0008), independent predictor of fatal and nonfatal cardiovascular events [hazard ratio (1 g x L(-1) increase in plasma fibrinogen): 1.25, 95% CI: 1.10-1.43] in a model including traditional risk factors and serum C-reactive protein (CRP) and plasma homocysteine. CONCLUSIONS: Fibrinogen is as an independent risk factor for overall and cardiovascular mortality in patients with ESRD. Intervention studies are required to see whether reducing plasma fibrinogen may help to curb the exceedingly high cardiovascular risk of the uremic population.

Fibrinogen, inflammation and concentric left ventricular hypertrophy in chronic renal failure.

BACKGROUND: We investigated the relationship between fibrinogen and echocardiographic measurements of left ventricular (LV) geometry and LV function in a group of 192 patients with end stage renal disease (ESRD). RESULTS: Patients in the third fibrinogen tertile had higher mean wall thickness (MWT), relative wall thickness (RWT) and left ventricular mass index (LVMI) and lower LV end diastolic diameter and LV ejection fraction than those in the other tertiles. On multivariate analysis fibrinogen resulted to be an independent correlate of MWT (P = 0.001) and RWT (P = 0.0001) and the first factor in rank explaining the variance in LV ejection fraction (P = 0.0001). Left ventricular concentric hypertrophy was more prevalent (P = 0.001) in patients in the third fibrinogen tertile (n = 35, 54%) than in those in the second (n = 24, 37%) and first (n = 13, 21%) tertiles. In a multiple logistic regression model patients in the third tertile of fibrinogen had a risk for left ventricular concentric hypertrophy that was 3.56 (95% CI: 1.56-8.14) fold higher than in those in the first tertile (P = 0.003). CONCLUSIONS: Elevated fibrinogen is independently associated with LV concentric hypertrophy and systolic dysfunction in ESRD patients. These relationships may contribute to the negative prognostic impact of elevated fibrinogen levels in ESRD.

Circulating natriuretic peptide concentrations in patients with end-stage renal disease: role of brain natriuretic peptide as a biomarker for ventricular remodeling.

OBJECTIVES: To determine levels of natriuretic peptides (NPs) in patients with end-stage renal disease (ESRD) and to examine the relationship of these cardiovascular peptides to left ventricular hypertrophy (LVH) and to cardiac mortality. PATIENTS AND METHODS: One hundred twelve dialysis patients without clinical evidence of congestive heart failure underwent plasma measurement of NP concentrations and echocardiographic investigation for left ventricular mass index (LVMI). RESULTS: Plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) concentrations correlated positively with LVMI and inversely with left ventricular ejection fraction, whereas C-type NP and Dendroaspis NP levels did not correlate with LVMI. In dialysis patients with LVH (LVMI >125 g/m2), plasma ANP and BNP concentrations were increased compared with those in dialysis patients without LVH (both P<001). In a subset of 15 dialysis patients without LVH or other concomitant diseases, plasma BNP concentrations were not significantly increased compared with those in 35 controls (mean +/- SD, 20.1+/-13.4 vs 13.5+/-9.6 pg/mL; P=.06), demonstrating that the BNP concentration was not increased by renal dysfunction alone. Furthermore, the BNP level was significantly higher in the 16 patients who died from cardiovascular causes compared with survivors (mean +/- SD, 129+/-13 vs 57+/-7 pg/mL; P<.003) and was significantly associated with greater risk of cardiovascular death in Cox regression analysis (P<.001), as was the ANP level (P=.002). CONCLUSIONS: Elevation of the plasma BNP concentration is more specifically related to LVH compared with the other NP levels in patients with ESRD independent of congestive heart failure. Thus, BNP serves as an important plasma biomarker for ventricular hypertrophy in dialysis patients with ESRD.

Long-term CAPD patients are volume expanded and display more severe left ventricular hypertrophy than haemodialysis patients.

BACKGROUND: Whether hypertension and left ventricular hypertrophy (LVH) are more prevalent in CAPD than in haemodialysis (HD) patients is still under discussion. METHODS: To examine this problem we compared a group of 51 CAPD patients, with a group of 201 HD patients. The evaluation included the measurement of atrial natriuretic peptide (atrial natriuretic factor (ANF)), taken as indicator of volume status, and echocardiographic measurements. RESULTS: CAPD patients were older, had been treated for a shorter time, and had lower serum albumin and phosphate than HD patients. Plasma ANF was higher (P<0.01) in CAPD (median 33.8 pmol/l (interquartile range 18.2-63.0)) than in HD patients (22.7 pmol/l (14.9-38.7)). Similarly, the left atrial volume was substantially higher (P<0.0001) in CAPD patients (49+/-22 ml) than in HD patients (37+/-17 ml), while the left ventricular end-diastolic diameter was similar in the two groups (CAPD 51+/-7 mm; HD 50+/-7 mm). Furthermore, left ventricular hypertrophy was more severe (P<0.0001) in CAPD (157+/-37 g/m(2)) than in HD patients (133+/-39 g/m(2)). The proportion of CAPD patients requiring antihypertensive drugs was markedly higher than that of HD patients (65 vs 38% P<0.001). Multivariate modelling showed that volume expansion and pressure load as well as serum albumin were independent predictors of left ventricular mass. CONCLUSIONS: Left ventricular hypertrophy is more severe in long-term CAPD patients than in HD patients. This finding is associated with evidence of more pronounced volume expansion, hypertension, and hypoalbuminaemia. Volume and pressure load along with factors associated with hypoalbuminaemia may aggravate LVH in uraemic patients on CAPD.

Diagnostic potential of cardiac natriuretic peptides in dialysis patients.

BACKGROUND: In the general population, the plasma concentrations of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are useful to predict left ventricular hypertrophy (LVH) and LV systolic dysfunction. Whether these cardiac hormones have a similar diagnostic potential in dialysis patients is unknown. METHODS: We studied the diagnostic value of ANP and BNP for alterations in LV mass and function in a cohort of 246 dialysis patients without clinical evidence of heart failure. RESULTS: Both ANP and BNP were independently related to left ventricular mass (P < 0.0001) as well as to ejection fraction (P < 0.0001). In an analysis based on a prospectively defined threshold (95th percentile of the normal range), BNP had a significantly higher (P < 0.01) sensitivity (88%) than ANP (51%) for the diagnosis of LVH, but the positive predictive value of the two peptides was very similar (92 and 87%, respectively, P = NS). However, the negative predictive value of BNP for excluding LVH was 22% higher than that of ANP (53 vs. 31%, P = 0.05). Both natriuretic peptides had a high sensitivity for the detection of LV dysfunction (87 and 94%), but their positive predictive value was low (25 and 15%). Importantly, both ANP and BNP proved to be very useful for excluding this alteration (negative predictive value 97 and 96%, respectively). An analysis based on the "best cut-offs" of each peptide as identified on the basis of the ROC curves augmented the positive and negative prediction values of BNP for the diagnosis of LVH to 95 and 61%, respectively. This approach also raised the BNP-positive prediction value for the identification of LV dysfunction to 31% but did not modify the diagnostic potential of ANP (either for LVH or for LV dysfunction). CONCLUSIONS: Measuring the plasma concentration of cardiac natriuretic hormones, particularly BNP, may be useful for the identification of dialysis patients with LVH or for excluding systolic dysfunction.

Hepatocyte growth factor predicts survival and relates to inflammation and intima media thickness in end-stage renal disease.

Hepatocyte growth factor (HGF) is a pleiotropic cytokine involved in tissue protection and repair in the endothelium and various organ systems. The serum concentration of this protein is markedly increased in patients with chronic renal diseases, but the clinical and pathophysiological correlates of this substance in renal failure are scarcely understood. Serum HGF, lipid, albumin, hemoglobin, C-reactive protein (CRP), and immunoglobulin G (IgG) were measured in fasting conditions in a cohort of 244 dialysis patients. In addition, the relationship between HGF and severity of carotid atherosclerosis was studied in a subgroup of 105 patients. The entire cohort was followed up for a median of 31 months (interquartile range, 21 to 34 months). Serum HGF level was directly related to duration of dialysis treatment, CRP level, age, IgG level, and hemoglobin level and inversely related to systolic and diastolic arterial blood pressure. In a multiple regression model, only duration of dialysis treatment (r = 0.38), age (r = 0.26), hemoglobin level (r = 0.17), IgG level (r = 0.15), and CRP level (r = 0.14) were independent correlates of serum HGF level (R = 0.54; P < 0.0001), suggesting that increased levels of serum HGF may be the expression of a chronic inflammatory process. HGF levels were greater in hemodialysis than continuous ambulatory peritoneal dialysis patients, independent of the type of dialysis membrane, and slightly increased in patients seropositive for hepatitis C virus. In the subgroup of patients who underwent echo color Doppler studies, serum HGF level was an independent correlate of intima media thickness (IMT; partial r = 0.23; P = 0.02). In the entire cohort, increased HGF levels predicted shorter survival in a multivariate Cox regression model. These results support the hypothesis that in patients with chronic renal failure, increased serum HGF level is linked to an inflammatory state. The relationships between HGF level and survival and IMT suggest that this cytokine might be a marker of a process that has a major impact in the high mortality and morbidity of the dialysis population.

Inflammation is associated with carotid atherosclerosis in dialysis patients. Creed Investigators. Cardiovascular Risk Extended Evaluation in Dialysis Patients.

OBJECTIVE: To investigate the relationship between inflammatory processes and atherosclerosis in uraemic patients on chronic dialysis. DESIGN: A cross-sectional study in 138 dialysis patients (92 on haemodialysis and 46 on continuous ambulatory peritoneal dialysis). METHODS: Serum C-reactive protein (CRP), IgG anti-Chlamydia pneumoniae antibodies, lipoprotein (a), fibrinogen and plasma homocysteine as well as the intima-media thickness and the number of atherosclerotic plaques of the carotid arteries (by Echo-Colour-Doppler) were measured in each patient RESULTS: One hundred and eight patients had at least one plaque and 26 had more than six plaques. Serum CRP was above the upper limit of the normal range (5 mg/I) in 85 of 138 patients (62%). IgG anti-Chlamydia pneumoniae antibodies were detectable in 64% of patients (high level in 24%, intermediate in 33% and low in 7%) and undetectable in the remaining 36% of patients. In a multiple regression model age (beta=0.35), serum CRP (beta=0.23), plasma homocysteine (beta=0.19), duration of dialysis (beta=0.19) and pulse pressure (beta=0.18) were independent predictors of intima-media thickness (R=0.54, P < 0.0001). Similarly, age (beta=0.33), serum CRP (beta=0.29), plasma homocysteine (beta=0.20) and serum albumin (beta=-0.18) were independent correlates of the number of atherosclerotic plaques (R = 0.55, P < 0.0001 ). Furthermore, in smokers, the interaction serum CRP-IgG anti-Chlamydia pneumoniae antibodies was the stronger independent predictor (beta=0.43, P=0.0001) of the number of atherosclerotic plaques while no such relationship (P=0.73) was found in non-smokers. CONCLUSIONS: In patients on chronic dialysis treatment CRP is independently associated to carotid atherosclerosis and appears at least in part to be explained by IgG anti-Chlamydia pneumoniae antibodies level. These data lend support to the hypothesis that inflammation plays a role in the pathogenesis of atherosclerosis in these patients.

Renal endothelin-1 is linked to changes in urinary salt and volume in essential hypertension. Salt Sensitivity Group of the Italian Society of Hypertension.

METHODS: We investigated the influence of salt intake on urinary and plasma endothelin-1 (ET-1) in 55 patients who entered a two-week double-blind, randomised, crossover study comparing a 50 mMol/day salt intake and 150 mMol/day. Twenty-four-hour ET-1 excretion and plasma ET-1 were measured by RIA on pre-extracted samples. RESULTS: In the whole cohort (n=55), changes in urinary ET-1 were related to salt excretion (r=0.28, P=0.04) and urinary volume (r=0.47, P=0.0001). In a multivariable model, changes in PRA, plasma aldosterone, blood pressure and heart rate did not add any predictive power to salt excretion with regard to urinary ET-1 variations. The relationship between urinary volume and urinary ET-1 was stronger than that of urinary sodium with ET-1 excretion because sodium was excluded from the multivariable model when urinary volume was introduced. Changes in urinary ET-1 were unrelated to mean blood pressure changes (P=0.66). Changes in plasma ET-1 were unaffected by changes in salt intake (P=0.58) but were strongly related to those in PRA (r= -0.45, P=0.01) and plasma aldosterone (r= -0.53, P=0.002). CONCLUSIONS: The renal excretion of ET-1 is influenced by changes in salt intake and appears largely independent of the blood pressure response to salt. Changes in urinary volume which accompany variations in salt excretion play an important role in this response. Since urinary ET-1 reflects its renal synthesis, our data support the notion that renal ET-1 plays a role in the regulation of sodium balance in patients with mild hypertension.

Impact of a 4-week treatment with prostaglandin E1 on health-related quality of life of patients with intermittent claudication.

Intermittent claudication impairs functional status and quality of life in many patients by limiting walking capacity. The aim of this study was to evaluate the effects of a 4-week treatment with prostaglandin E1 (PGE1), a drug inducing vasodilation and inhibiting platelet aggregation, on improving functional status and health-related quality of life in patients with disabling intermittent claudication. Forty-two untrained outpatients (37 men and five women, mean age 64 +/- 8 years) with intermittent claudication,and maximum walking distance (MWD) of at least 50 and no more than 200 m on treadmill test (5% slope, 3 km/hr) were randomized to 4 weeks of double-blind treatment either with 60 mcg PGE1 daily given IV in 250 mL saline over a period of 2 hours (21 patients) or placebo (250 mL saline, 21 patients). Treatment-free follow-up was completed 8 weeks after the final infusion. Pain free walking distance (PFWD), MWD, and questionnaire evaluation were determined at baseline, after the 4-week treatment period, and at the end of the 8 weeks of the treatment-free follow-up period. After 4 weeks of treatment with PGE1 PFWD and MWD increased from 72 +/- 16 m to 135 +/- 33 m (+87%, p<0.001)and from 140 +/- 30 m to 266 +/- 62 m (+90%, p<0.001), respectively. Analysis of the Walking Impairment Questionnaire responses in the PGE1 group at 4 weeks demonstrated significant improvements in the walking impairment score (+19 percentage points, p<0.001), in the distance score (+25 percentage points, p<0.001), in the speed score (+24 percentage points, p<0.001), in the stair climbing score (+20 percentage points, p<0.001). The RAND survey responses showed improvements in physical function and bodily pain scores (+14 percentage points, p<0.001, and +15 percentage points, p<0.01, respectively). After the treatment-free follow-up period of 8 weeks, increases in PFWD and MWD were maintained (113 +/- 26 m, +57%, p<0.001, and 229 +/- 55 m, +63%, p<0.001, respectively). Similarly, at the end of the treatment-free follow-up, the walking impairment score (+16 percentage points, p<0.001), the distance score (+23 percentage points, p<0.001), the speed score (+22 percentage points, p<0.001), the stair climbing score (+18 percentage points, p<0.001) as well as the RAND physical function and bodily pain scores (+10 percentage points, p<0.001, and +13 percentage points, p<0.01, respectively) were still increased compared with baseline. No change from baseline was found in all the target parameters in the placebo group after 4 weeks of treatment and at the end of the treatment-free follow-up period. These data show that a 4-week treatment with PGE1 improves functional status and quality of life as well as treadmill performance in patients with disabling intermittent claudication as compared with placebo-treated patients. The improvements are also maintained for a period of 8 weeks beyond the end of the treatment. Additional studies are needed to determine the duration of functional benefits after the end of treatment.

Treadmill exercise-induced release of endothelin-1 in patients with peripheral arterial occlusive disease at Fontaine stage IIb.

BACKGROUND: Endothelin-1 (ET-1) is an endothelial vasoconstrictor mitogenic peptide which is thought to be a marker of endothelial damage and a potential participant in the pathophysiological processes of the development of atherosclerotic lesions and disease states associated with vasoconstriction and vasospasm. METHODS: To investigate the endothelin-1 release in response to dynamic exercise in patients with peripheral arterial occlusive disease (PAOD), plasma concentrations were determined by radioimmunoassay in 16 patients (14 men, 2 women, mean age 56.2 +/- 8.1 years) with peripheral arterial occlusive disease at Fontaine stage IIb and in 10 control subjects (8 men, 2 women, mean age 58.1 +/- 7.2 years) in normal health during treadmill testing (slope 5%, speed 3 km/hr). Blood samples were collected at rest from an antecubital vein, at the onset of claudication pain, and 10 minutes after exercise. RESULTS: Mean plasma endothelin-concentrations during the stress test increased significantly in the patients with arterial disease, rising from basal values of 4.4 +/- 0.6 pmol/L to values of 8.9 +/- 0.7 pmol/L at the end of the test (p < 0.0001), whereas it did not change significantly in control subjects (rising from 2.6 +/- 0.4 pmol/L to 2.7 +/- 0.5 pmol/L). Further, plasma endothelin- in the patients with arterial disease was at all times higher than in the control subjects (p < 0.0001). CONCLUSIONS: In conclusion, this study shows that in patients with peripheral arterial occlusive disease, plasma endothelin-1 increases after treadmill exercise performed until claudication pain supervenes. Raised endothelin-1 could be a marker of ischaemic acute endothelial damage and/or could contribute to increase the vascular resistance in ischaemic limbs of these patients during dynamic exercise by promoting arterial/arteriolar vasoconstriction or vasospasm.

Smoking, blood pressure and serum albumin are major determinants of carotid atherosclerosis in dialysis patients. CREED Investigators. Cardiovascular Risk Extended Evaluation in Dialysis patients.

AIM: To investigate the relationship between carotid atherosclerosis and some major cardiovascular risk factors in uremic patients on chronic dialysis. METHODS: A cross-sectional study was carried out in 119 unselected dialysis patients (89 on hemodialysis and 30 on chronic ambulatory peritoneal dialysis, CAPD). Fasting blood sampling for serum lipids, albumin, hemoglobin, and echo-colour-Doppler evaluation of common carotid arteries were performed in all patients (during the non-dialysis day in hemodialysis patients). In hemodialysis patients BP was measured before and after dialysis; in CAPD patients home BP values were recorded during the month before the study day. RESULTS: Ninety-five patients had at least one plaque and 57 had at least four plaques. Thirty-eight had mild and eleven severe carotid stenosis. In multiple regression models, the mean internal diameter of carotid arteries was explained (R=0.52, P=0.0001) by systolic pressure (r=0.39), serum cholesterol (r=-0.28), age (r=0.27) and smoking (r=0.24) while the degree of carotid stenosis was predicted (R=0.39, P=0.0001) by age (r=0.36) and smoking (r=0.25). The number of atherosclerotic plaques was explained (R=0.51, P=0.0001) by age (r=0.36), smoking (r=0.25) and pulse pressure (r=0.20), serum albumin just failing to reach statistical significance (P = 0.06). However, serum albumin was a significant and independent predictor of the number of atherosclerotic plaques (r=-0.26) in hemodialysis patients (n=89). Sex, diabetes, Kt/V, duration of dialysis treatment, hemoglobin, serum calcium and phosphate did not add any predictive power to the models. CONCLUSIONS: In dialysis patients arterial pressure and smoking are associated with carotid atherosclerosis. Serum albumin appears to serve as an independent predictor of carotid atherosclerosis.

Effects of a 4-week treatment with prostaglandin E1 on plasma endothelin-1 release in patients with intermittent claudication.

OBJECTIVE: Endothelin-1 (ET-1) is a vasoconstrictor mitogenic peptide whose plasma concentrations are increased in patients with peripheral arterial occlusive disease (PAOD). The aim of this study was to investigate whether changes in plasma ET-1 concentrations occur after a 4-week treatment with prostaglandin (PG) E1 in patients with intermittent claudication. PATIENTS, MATERIAL AND METHODS: Twenty-four non-trained outpatients with Fontaine stage II PAOD (20 men and 4 women, mean age 63+/-7 years, age range 48-72 years) were randomized to receive over a 4-week period either PGE1 (60 microg given daily i.v. over 2 hours in 250 ml saline, n = 12) or placebo (250 ml saline, n = 12). Plasma levels of ET-1 were measured by radioimmunoassay at baseline and after treatment period. Before and after treatment pain-free walking distance (PFWD) and maximum walking distance (MWD) were evaluated by treadmill walking test as the target parameters for assessing treatment efficacy. RESULTS: At week 4, PFWD and MWD significantly increased in comparison to baseline only in PGE1 treatment group (from 136+/-38 m to 246+/-95 m, p = 0.0004, and from 238+/-54 m to 411+/-137 m, p = 0.0001, respectively). At the end of the treatment period with PGE1, ET-1 plasma concentration decreased from 4.50+/-0.8 pmol/l to 3.6+/-1.1 pmol/l (p = 0.002), whereas it remained unchanged in placebo group. A significant correlation between the decrease in ET-1 plasma levels and the increase in the PFWD and MWD (r = -0.92, p < 0.0001; r = -0.78, p = 0.002, respectively) was detected in PGE1 treatment group. CONCLUSIONS: Reduced ET-1 plasma concentrations after PGE1 treatment could be an index of improved endothelial function and/or could contribute to a reduction in vascular resistance and vessel wall growth in PAOD patients. Moreover, plasma ET-1 could be a marker of clinical improvement in these patients.

Plasma endothelin-1 levels in patients with peripheral arterial occlusive disease at different Fontaine's stages.

UNLABELLED: Endothelin-1 (ET-1) is a potent vasoconstrictor and mitogenic peptide produced and secreted by endothelial cells, which can play a potential role in the development of atherosclerosis and in the pathophysiology of extreme vasoconstriction of various diseases. METHODS: To assess plasma endothelin-1 (ET-1) concentrations in patients with peripheral arterial occlusive disease (PAOD) at different Fontaine's stages, we measured plasma ET-1 by radioimmunoassay in 14 stage II PAOD patients (12 men, 2 women; mean age 59.5 +/- 3.4 years) and in 10 stage III-IV PAOD patients (8 men, 2 women, mean age 61.2 +/- 3.3 years). Ten normal subjects (8 men, 2 women, mean age 58.1 +/- 7.2 years) were considered as controls. RESULTS: Mean (+/- SD) plasma ET-1 levels, as measured by radioimmunoassay, were significantly greater in stage II and stage III-IV PAOD patients than in control subjects (4 +/- 0.4 and 5 +/- 0.4 pmol/L vs 2.5 +/- 0.6 pmol/L, respectively, p < 0.001). Furthermore, plasma levels of ET-1 in stage III-IV patients were significantly higher than in stage II patients (p < 0.01). A significant correlation was found between plasma ET-1 levels and number of the arterial obstructive lesions in PAOD patients (r = 0.698; p < 0.0001). No significant correlation was found between plasma ET-1 concentrations and pain-free walking distance (r = -0.279, p = 0.333, in stage II patients; r = 0.137, p = 0.705, in stage III-IV patients), and between plasma ET-1 levels and ankle/arm pressor index (r = 0.032, p = 0.913, in stage II patients; r = 0.149, p = 0.681, in stage III-IV patients) in the PAOD patients. CONCLUSIONS: Raised plasma ET-1 could be a sensible marker both of endothelial damage and disease extension. It could also promote the progression of atherosclerotic plaques and enhance the microvascular resistance in these patients.

Immunohistochemical modifications of vasoactive neuropeptides and excitatory amino acids in the nervous tissue of the Mongolian gerbil after transient cerebral ischemia.

Modifications in the tissue concentration of vasoactive peptides (Endothelin, Calcitonin Gene Related Peptide, Atrial Natriuretic Peptide) and excitatory amino acids (glutamate, aspartate) were found in the nervous tissue of Mongolian gerbils after transient cerebral ischemia which was induced by unilateral occlusion of the common carotid artery for 30 min 4 h. In fact, immunostaining for these peptides was more intense in the ischemic tissue: the greatest increases of tissue immunoreactivity were observed for Endothelin; smaller differences were found for Calcitonin Gene Related Peptide and Atrial Natriuretic Peptide. Immunostaining for Neuropeptide Y, another vasoactive neuropeptide, was virtually unchanged. Infarct areas, when present, contained numerous Endothelin-immunoreactive cell bodies. On the contrary, the same areas were completely void of glutamate- or aspartate-immunostained neurons, normally present in the correspondent regions of the control tissue. The present results suggest that severe cerebral ischemia is paralleled by an unbalance of local vasoactive factors. The predominance of vasoconstrictor action of Endothelin might play a major role in the irreversible damage, together with the excitotoxic effect of the extracellular accumulation of excitatory amino acids, probably due to a leakage from neuronal cell somata, as suggested by the disappearance of glutamate- or aspartate-immunostained neurons.

The relationship between cardiac output and posthyperventilation hyperpnoea in patients with essential hypertension.

Posthyperventilation hyperpnoea (PHVH) is the progressive decline in minute ventilation (V'E) that follows abrupt cessation of voluntary hyperventilation. It has been hypothesized that the increase in cardiac output (CO) during hyperventilation could contribute to the duration of PHVH. This hypothesis was tested by measuring the duration of PHVH in patients with essential hypertension, in whom the increase in CO as a result of various stimuli is less pronounced. Twenty male hypertensives (mean arterial blood pressure+/-SEM: 178/ 107+/-3/1 mmHg), and 12 age-matched male healthy subjects were studied. The study consisted of three periods: control (5 min), voluntary hyperventilation (2 min), and recovery (3 min). V'E, CO, end-tidal CO2 and O2 tensions were measured, and the time constant (tau) of the V'E decay during recovery calculated. The V'E decay was faster in hypertensives (tau: 0-8.4 s) than in healthy subjects (tau: 12-59 s; p<0.01). During voluntary hyperventilation, CO increased to a lesser extent in hypertensives (6.8+0.7 L.min(-1)) than in healthy subjects (12.9+/-1.1 L.min(-1); p<0.01). In hypertensives, changes in CO during voluntary hyperventilation were significantly related to tau (r=0.646; n=20; p=0.002). The less pronounced rise in cardiac output during hyperventilation in hypertensives could account for the shorter duration of posthyperventilation hyperpnoea.

Plasma endothelin-1 concentrations in non-insulin-dependent diabetes mellitus and nondiabetic patients with chronic arterial obstructive disease of the lower limbs.

BACKGROUND: Endothelin-1 (ET-1), a vasoconstrictor and mitogenic endothelium-derived peptide, has been considered as a marker for endothelial damage and potential contributor to the development of the atherogenic process. METHODS: To evaluate the pattern of plasma ET-1 secretion in non-insulin-dependent diabetes mellitus (NIDDM) and nondiabetic patients with chronic arterial obstructive disease (CAOD) of the lower limbs, plasma levels of ET-1 were determined in 12 NIDDM patients (10 men and 2 women; mean age 63+/-8 years) with CAOD of the lower limbs at Fontaine stage II and in 12 nondiabetic patients (11 men and 1 woman; mean age 62+/-4 years) with comparable arteriopathy. Ten normal subjects comprised the control population. RESULTS: The plasma levels of ET-1 in NIDDM patients with CAOD of the lower limbs were 5.7+/-0.3 pmol/L, which represented a significant (p<0.001) difference from the values in nondiabetic patients with comparable arteriopathy (4.1+/-0.6 pmol/L) and those in the control group (2.7+/-0.7 pmol/L). Plasma levels of ET-1 showed a significant (p<0.0001) positive correlation with the levels of fasting insulin in NIDDM patients with CAOD of the lower limbs. Increased plasma ET-1 could reflect a major and/or more diffuse endothelial cell damage or dysfunction in NIDDM than in nondiabetic patients with comparable CAOD of the lower limbs. Augmented mitogenic ET-1 levels could also have a role both in diabetic and nondiabetic angiopathy. CONCLUSIONS: The positive correlation between ET-1 plasma levels and fasting insulin levels in NIDDM patients with CAOD of the lower limbs suggests that the increased ET-1 release could be related to the augmented insulin secretion in these patients. Insulin-related overproduction of ET-1 could promote the atherogenic process and enhance the vascular tone to a greater extent in NIDDM than in nondiabetic patients with CAOD of the lower limbs.

Diagnosis of renovascular disease by extra- and intrarenal Doppler parameters.

It is still a matter of debate as to which parameters should be used for noninvasive diagnosis of renovascular disease by renal Doppler sonography (RDS). The accuracy of RDS in the detection of renal artery stenosis (RAS) was tested in 95 consecutive, moderate to severe hypertensive patients (I-II World Health Organization [WHO] stages). Reno-aortic ratio (RAR) for peak systolic velocity (PSV) was also calculated to assist in the diagnosis of significant (>50%) RAS. Paired receiver-operating characteristic (ROC) analysis was plotted for evaluating the relationship between sensitivity and specificity for each parameter. In a subset of 57 kidneys, the influence of blood pressure and age on intraparenchymal parameters was evaluated. Measurements of maximal peak systolic velocity (PSV) at the site of stenosis, RAR for PSV, and minimum acceleration index in the main renal artery showed high accuracy (areas under the ROC curve 0.97, 0.88, and 0.80, respectively). Among intraparenchymal parameters, early systolic acceleration showed the best area under the ROC curve (0.90), but provided a low positive predictive value (29%) and was significantly influenced by blood pressure (multiple r=0.56; p=0.001). Pulsatility and resistive indices were found to be less powerful as absolute values, and both significantly influenced by blood pressure and age (multiple r=0.60 and 0.50; p=0.001, p=0.02, respectively). However, interindividual variance of intrarenal indices should be minimized by calculation of side difference, although this procedure would become misleading or impossible in patients with bilateral RAS or a single kidney, respectively. These results support the use of extraparenchymal parameters for noninvasive detection of RAS, and emphasize that intrarenal parameters cannot be considered as absolute values.