Alberto Montanari

Plasma homocysteine and folate are related to arterial blood pressure in type 2 diabetes mellitus

The aim of this study was to assess the relationship between homocysteine (tHcy), folate and vitamin B12 levels, urinary albumin excretion, and arterial blood pressure in patients with non-insulin-dependent diabetes mellitus (NIDDM). Our study was carried out in 33 NIDDM patients (16 men, 17 women) and 16 healthy volunteers as controls (seven men, nine women). Fasting and postmethionine load plasma tHcy levels were assessed, together with folate, vitamin B12, and urinary albumin excretion levels. In NIDDM patients, there were correlations between folate and mean arterial pressure (r = -0.352, P = .046), folate and systolic blood pressure (r = -0.437, P = .013), folate and vitamin B12 (r = 0.499, P = .004), tHcy and vitamin B12 (r = -0.348, P = .04), ln tHcy and ln folate (r = -0.404, P = .01), and, lastly, between tHcy, either fasting or postload, and urinary albumin excretion. Patients with elevated tHcy levels had significantly higher diastolic blood pressure (P = .04) and mean arterial pressure (P = .03). Otherwise, higher folate values were associated with lower systolic blood pressure (P = .004) and mean arterial pressure (P = .02). In addition, NIDDM patients with complications presented higher tHcy basal values than the group without complications (P = .003). A particular propensity of such patients towards endothelial dysfunction could explain the presence of correlations between these metabolic parameters and arterial blood pressure.

Serum adipokine zinc α2-glycoprotein and lipolysis in cachectic and noncachectic heart failure patients: relationship with neurohormonal and inflammatory biomarkers

Chronic heart failure is often complicated by the development of cachexia with the loss of fat mass. Zinc α2-glycoprotein (ZAG) is a serum adipokine with lipolytic effects in cancer cachexia. We evaluated in patients with advanced heart failure with (CxHF) or without cachexia (nCxHF) the relationship of ZAG with circulating free fatty acid (FFA), as an index of lipolysis, and with other neurohormonal and inflammatory biomarkers. Two groups, nCxHF (n = 46) and CxHF (n = 18), the latter having a documented, involuntary, edema-free loss of body weight of at least 7.5% in the previous 6 months, underwent plasma determination of FFA, ZAG, norepinephrine (NE), tumor necrosis factor-α, and natriuretic peptide levels (atrial natriuretic, B-type natriuretic peptide). The patients were compared with age-matched healthy controls (CTR) (n = 21). Zinc α2-glycoprotein, atrial natriuretic peptide, B-type natriuretic peptide, and tumor necrosis factor-α circulating levels were similarly greater in CxHF and nCxHF than in CTR. Free fatty acid and NE were higher in CxHF than in nCxHF. A positive correlation between FFA and NE was found in both CxHF (r = 0.73, P < .01) and nCxHF (r = 0.48, P < .01) but only in CxHF between ZAG and FFA (r = 0.54, P = .02) and between ZAG and NE (r = 0.70, P < .01). No correlations between natriuretic peptides and ZAG were found. Serum ZAG levels are increased in advanced heart failure patients compared with CTR, without differences between CxHF and nCxHF. Only in CxHF, ZAG levels are directly correlated to circulating levels of FFA and NE, suggesting a close interaction of ZAG with sympathetic-mediated lipolysis.

Endothelin-A Blockade Attenuates Systemic and Renal Hemodynamic Effects of L-NAME in Humans

Eight Na-repleted volunteers underwent 3 separate 90-minute infusions of either N(G)-nitro-L-arginine methyl ester (L-NAME) 3.0 mg. kg(-1). min(-1) or endothelin-A receptor (ET-A) blocker BQ-123 (BQ) 0.125 nmol. kg(-1). min(-1) or both. Mean arterial pressure (MAP), glomerular filtration rate (GFR), renal blood flow (RBF), renal vascular resistances (RVR), and sodium excretion rate (UNaV) were measured at baseline (b) and from 0 to 45 minutes (period 1) and 45 to 90 minutes (period 2) of infusion. BQ alone had no effect. GFR declined by 4.9% (P<0.001 versus b) in period 1, to 9.9% (P<0. 001) in period 2 with L-NAME, and by 3.3% (P<0.01) to 6.6% (P<0.001) with L-NAME plus BQ (P=NS between L-NAME and L-NAME plus BQ). UNaV fell equally with L-NAME or L-NAME plus BQ. MAP rose significantly in period 2 with L-NAME (6.9%; P<0.001) but not with coinfused BQ (2. 1%; P=NA versus b, P=0.005 versus L-NAME alone). RBF declined by 12. 2% (P<0.001) to 18.3% (P<0.001) with L-NAME and by 4.6% (P<0.005) to 8.2% (P<0.001) with L-NAME plus BQ. These changes were smaller with L-NAME plus BQ (P<0.05 in period 1 and P<0.02 in period 2). Blunted changes were also seen for RVR (P<0.005 in period 1 and P<0.001 in period 2 between L-NAME alone and L-NAME plus BQ). These findings show that systemic and renal vasoconstriction due to L-NAME are attenuated by BQ, which suggests that an interaction between endogenous nitric oxide production and ET-A activity participates in the maintenance of baseline systemic and renal vascular tone in humans.

Endothelial dysfunction and cardiovascular risk profile in long-term withdrawing alcoholics.

Background Rates of cardiovascular morbidity and mortality are greater in heavy alcoholics than in either teetotallers or light-to-moderate drinkers. Objective On the assumption that factors leading to atherosclerotic damage remain operative even after long-term alcohol withdrawal, we studied the possible mechanisms of raised cardiovascular risk in former heavy alcoholics. Methods Forty-two apparently disease-free, normotensive alcoholics detoxified for 37.1 ± 31.9 (SD) months, median 24, participated in the study. They were compared with 39 lifetime alcohol-abstaining control subjects, carefully matched for age, sex, body mass index, smoking and dietary habits, physical activity, lipids and fasting glucose. Endothelial function (flow-mediated dilation of brachial artery, high-resolution ultrasound technique), blood pressure, and some parameters of endothelial activation, oxidative stress, vascular inflammation and insulin sensitivity were measured. Results The maximal percentage of flow-mediated dilatation was reduced in detoxified alcoholics (10.1 ± 4.6 versus 14.9 ± 7.4, P < 0.001) who also showed significantly higher blood pressure (systolic 127.5 ± 12.9 versus 118.2 ± 10.7 mmHg, P < 0.001; diastolic 79.4 ± 7.1 versus 74.6 ± 6.4 mmHg, P < 0.01; mean 95.4 ± 8.2 versus 89.1 ± 7.3 mmHg, P < 0.001), uric acid (5.0 ± 1.1 versus 4.4 ± 0.8 mg/dl, P < 0.05), high-sensitivity C-reactive protein (2.1 ± 2.0 versus 1.0 ± 0.9 mg/l, P < 0.01), endothelin-1 (0.38 ± 0.11 versus 0.17 ± 0.10 pg/ml, P < 0.001) and fasting insulin (10.4 ± 4.5 versus 5.6 ± 1.6 μU/ml, P < 0.001) with abnormal homeostasis model assessment index of insulin resistance (2.3 ± 1.1 versus 1.2 ± 0.4, P < 0.001). Conclusion Previous heavy alcoholism, in spite of long-term withdrawal, is associated with endothelial dysfunction and a wide cluster of haemodynamic, vascular and metabolic abnormalities that indicate an unfavourable cardiovascular and metabolic risk profile even in apparently disease-free former alcoholics.

Endothelin-A Receptors Mediate Renal Hemodynamic Effects of Exogenous Angiotensin II in Humans

Abstract—To investigate whether endothelin-A receptors mediate hemodynamic changes caused by exogenous Angiotensin II in humans, 7 healthy volunteers on a 250-mmol sodium diet underwent 3 separate p-aminohippurate and inulin-based renal hemodynamic studies. In 2 studies, Angiotensin II (increasing rates of 0.625, 1.25, and 2.5 ng/kg per minute, each for 30 minutes) was infused either alone or combined with endothelin-A blocker, BQ123, 0.4 nmol/kg per minute. A third infusion of BQ123 alone was not followed by any change. Angiotensin II infusion alone produced a progressive decrease in renal blood flow (1080±94 mL/min×1.73 m2 to 801±52, P <0.001, versus baseline) and glomerular filtration rate (115±7 mL/min×1.73 m2 to 97±7, P <0.001) with increase in filtration fraction (0.188±.017 to 0.220±.030, P <0.01). Mean arterial pressure and renal vascular resistance increased markedly (86.8±3.1 to 97.5±4.4 mm Hg, P <0.001 and 83±7 to 133±20 mm Hg/min per liter, P <0.001, respectively). With Angiotensin II+BQ 123, mean arterial pressure still rose (86.2±3.1 to 91.1±4.3, P <0.05 versus both baseline and BQ123 alone) but significantly less than with Angiotensin II alone (P <0.05). Renal blood flow (1077±76 to 993±79, P <0.001) and glomerular filtration rate (115±7 to 105±7, P <0.05) also changed to a significantly lesser extent than with Angiotensin II alone (P <0.05 for both), whereas filtration fraction remained unchanged (0.185±.015 to 0.186±.016). Renal vascular resistance rose only by 17% (82±5 to 95±9, P <0.001 versus baseline as well as versus BQ123 or Angiotensin II alone). The results show that endothelin through Endothelin-A receptors contributes substantially to the systemic and renal vasoconstriction of low-dose exogenous Angiotensin II in healthy humans.

Angiotensin II blockade does not prevent renal effects of L-NAME in sodium-repleted humans

In seven healthy, young subjects on a 240 mmol sodium diet, mean arterial pressure (MAP), renal hemodynamics, and renal handling of Na and exogenous Li were measured at baseline and during short-term nitric oxide (NO) blockade with a 90-minute infusion of 3.0 microg x kg(-1) x min(-1) of N(G)-L-arginine methyl ester (L-NAME). The infusion was performed twice: after a 3-day pretreatment with either placebo or 50 mg losartan to block Ang II receptors. With placebo, L-NAME produced no change in MAP from 0 to 45 minutes (period 1) and only a 5% increase at 45 to 90 minutes (period 2) of infusion. Effective renal plasma flow (ERPF, PAH clearance) and glomerular filtration rate (GFR, inulin clearance) declined by 11.7% and 8.0%, respectively in period 1 and by 14.6% and 11.6%, respectively, in period 2. Calculated renal vascular resistance (RVR) increased by 13.0% to 20.6%. Fractional excretion of Na (FE(Na)) and Li (FE(Li)) fell by 30.0% and 21.0%, respectively, in period 1 and by 44.2% and 31.1% in period 2. All these variations were significant versus baseline. With losartan, the rise in MAP at 45 to 90 minutes was completely abolished, whereas all changes in ERPF, GFR, RVR, FE(Na), and FE(Li) in response to L-NAME were the same as those observed with placebo. The present data show that NO blockade with low-dose systemic infusion of L-NAME produces renal vasoconstriction, reduced GFR, and increased tubular Na reabsorption independent of changes in MAP. Reduced FE(Li) indicates an effect of NO on the proximal tubule. Since these changes are not prevented by losartan, we conclude that in Na-repleted humans, renal vasoconstriction and Na-retaining effects of inhibition of basal NO production are not due to the unopposed action of endogenous Ang II.

Plasma and Skeletal Muscle Free Amino Acids in Type I, Insulin-treated Diabetic Subjects

Insulin-dependent diabetes mellitus (IDDM) induces plasma amino acid (AA) abnormalities, including low alanine and high branched-chain (BCAA). While insulin treatment restores plasma AA pattern, proline, methionine, valine, isoleucine, and total BCAA remain elevated in skeletal muscle intracellular water. This suggests that the restoration of plasma AA concentrations is not a satisfactory index of recovered AA metabolism in IDDM.

Low Serum Ferroxidase I Activity Is Associated With Mortality in Heart Failure and Related to Both Peroxynitrite-Induced Cysteine Oxidation and Tyrosine Nitration of Ceruloplasmin

Rationale: Ceruloplasmin antioxidant function is mainly related to its ferroxidase I (FeOxI) activity, which influences iron-dependent oxidative and nitrosative radical species generation. Peroxynitrite, whose production is increased in heart failure (HF), can affect ceruloplasmin antioxidant function through amino acid modification. Objective: We investigated the relationship between FeOxI and ceruloplasmin tyrosine and cysteine modification and explored in a cohort of patients with HF the potential clinical relevance of serum FeOxI. Methods and Results: In patients with chronic HF (n=96, 76±9 years; New York Heart Association class, 2.9±0.8) and age-matched controls (n=35), serum FeOxI, FeOxII, ceruloplasmin, nitrotyrosine-bound ceruloplasmin, B-type natriuretic peptide, norepinephrine, and high-sensitivity C-reactive protein were measured, and the patients were followed up for 24 months. Ceruloplasmin, B-type natriuretic peptide, norepinephrine, and high-sensitivity C-reactive protein were increased in HF versus controls. FeOxI was decreased in HF (−20%) and inversely related to nitrotyrosine-bound ceruloplasmin (r, −0.305; P=0.003). In HF, FeOxI lower tertile had a mortality rate doubled compared with middle-higher tertiles. FeOxI emerged as a mortality predictor (hazard ratio, 2.95; 95% confidence intervals [1.29–6.75]; P=0.011) after adjustment for age, sex, hypertension, smoking, sodium level, estimated glomerular filtration rate, and high-sensitivity C-reactive protein. In experimental settings, peroxynitrite incubation of serum samples and isolated purified ceruloplasmin reduced FeOxI activity while increasing ceruloplasmin tyrosine nitration and cysteine thiol oxidation. Reduced glutathione prevented peroxynitrite-induced FeOxI drop, tyrosine nitration, and cysteine oxidation; flavonoid(−)-epicatechin, which prevented ceruloplasmin tyrosine nitration but not cysteine oxidation, partially impeded peroxynitrite-induced FeOxI drop. Conclusions: Reduced activity of serum FeOxI is associated with ceruloplasmin nitration and reduced survival in patients with HF. Both ceruloplasmin tyrosine nitration and cysteine thiol oxidation may be operant in vivo in peroxynitrite-induced FeOxI activity inhibition.

Prealbumin improves death risk prediction of BNP-added Seattle Heart Failure Model: Results from a pilot study in elderly chronic heart failure patients

BACKGROUND An accurate prognosis prediction represents a key element in chronic heart failure (CHF) management. Seattle Heart Failure Model (SHFM) prognostic power, a validated risk score for predicting mortality in CHF, is improved by adding B-type natriuretic peptide (BNP). We evaluated in a prospective study the incremental value of several biomarkers, linked to different biological domains, on death risk prediction of BNP-added SHFM. METHODS Troponin I (cTnI), norepinephrine, plasma renin activity, aldosterone, high sensitivity-C reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), interleukin 2 soluble receptor, leptin, prealbumin, free malondialdehyde, and 15-F2t-isoprostane were measured in plasma from 142 consecutive ambulatory, non-diabetic stable CHF (mean NYHA-class 2.6) patients (mean age 75±8years). Calibration, discrimination, and risk reclassification of BNP-added SHFM were evaluated after individual biomarker addition. RESULTS Individual addition of biomarkers to BNP-added SHFM did not improve death prediction, except for prealbumin (HR 0.49 CI: (0.31-0.76) p=0.002) and cTnI (HR 2.03 CI: (1.20-3.45) p=0.009). In fact, with respect to BNP-added SHFM (Harrells C-statistic 0.702), prealbumin emerged as a stronger predictor of death showing the highest improvement in model discrimination (+0.021, p=0.033) and only a trend was observed for cTn I (+0.023, p=0.063). These biomarkers showed also the best reclassification statistic (Integrated Discrimination Improvement-IDI) at 1-year (IDI: cTnI, p=0.002; prealbumin, p=0.020), 2-years (IDI: cTnI, p=0.018; prealbumin: p=0.006) and 3-years of follow-up (IDI: cTnI p=0.024; prealbumin: p=0.012). CONCLUSIONS Individual addition of prealbumin allows a more accurate prediction of mortality of BNP enriched SHFM in ambulatory elderly CHF suggesting its potential use in identifying those at high-risk that need nutritional surveillance.

Sodium Sensitivity of Blood Pressure in Long-Term Detoxified Alcoholics

To investigate whether sodium sensitivity of blood pressure participates in the relationship of arterial hypertension to chronic alcohol consumption, 30 alcoholics detoxified from 6 to 12 months and 30 teetotaler controls underwent a dietary sodium manipulation study. They received a daily 55 mmol sodium diet for 7 days, followed by a 260 mmol sodium diet for 7 days. Changes in 24-hour urinary sodium excretion between the end of each period were similar in alcoholics and controls (202+/-16 SEM mmol and 227+/-11, respectively). Plasma renin activity in alcoholics was lower than in controls at both low (2.4+/-0.4 ng angiotensin I/mLxh(-1) versus 3. 7+/-0.2, P<0.003) and high sodium intake (0.47+/-0.10 versus 0. 82+/-0.10, P<0.05), with smaller variations in alcoholics (-1.9+/-0. 3 versus -2.9+/-0.2, P<0.009). In alcoholics, alteration in sodium intake was followed by greater changes in both systolic and mean blood pressure (ambulatory blood pressure monitoring), which rose by 10.6+/-2.2 mm Hg and 7.3+/-1.5 versus 4.7+/-1.4 and 3.9+/-1.0 in controls, respectively (P<0.03 for systolic and P<0.05 for mean blood pressure). The ratio of changes in mean blood pressure to those in 24-hour urinary sodium excretion was higher in alcoholics (0.044+/- 0.011 mm Hgxmmol(-1) versus 0.018+/-0.0041, P<0.005). Our data show that in detoxified alcoholics, there is an abnormal response of both blood pressure and plasma renin activity to variations in salt intake similar to that in sodium-sensitive arterial hypertension. The precise relationship between the sodium sensitivity of blood pressure in detoxified alcoholics and the long-term influence of alcohol on blood pressure remains to be elucidated.