Ilaria Cecioni

Cardiac Growth Factors in Human Hypertrophy Relations With Myocardial Contractility and Wall Stress

The aim of the present study was to investigate whether and which cardiac growth factors are involved in human hypertrophy, whether growth factor synthesis is influenced by overload type and/or by the adequacy of the hypertrophy, and the relationships between cardiac growth factor formation and ventricular function. Cardiac growth factor formation was assessed by measuring aorta-coronary sinus concentration gradient in patients with isolated aortic stenosis (n=26) or regurgitation (n=15) and controls (n=12). Gene expression and cellular localization was investigated in ventricular biopsies using reverse transcriptase-polymerase chain reaction and in situ hybridization. Cardiac hypertrophy with end-systolic wall stress <90 kdyne/cm2 was associated with a selective increased formation of insulin-like growth factor (IGF)-I in aortic regurgitation and of IGF-I and endothelin (ET)-1 in aortic stenosis. mRNA levels for IGF-I and preproET-1 were elevated and mainly expressed in cardiomyocytes. At stepwise analysis, IGF-I formation was correlated to the mean velocity of circumferential fiber shortening (r=0.86, P<0.001) and ET-1 formation to relative wall thickness (r=0.82, P<0. 001). When end-systolic wall stress was >90 kdyne/cm2, IGF-I and ET-1 synthesis by cardiomyocytes was no longer detectable, and only angiotensin (Ang) II was generated, regardless of the type of overload. The mRNA level for angiotensinogen was high, and the mRNA was exclusively expressed in the interstitial cells. Ang II formation was positively correlated to end-systolic stress (r=0.89, P<0.001) and end-diastolic stress (r=0.84, P<0.001). Multivariate stepwise analysis selected end-systolic stress as the most predictive variable and left ventricular end-diastolic pressure as the independent variable for Ang II formation (r=0.93, P<0.001). In conclusion, the present results indicate that the course of human left ventricular hypertrophy is characterized by the participation of different cardiac growth factors that are selectively related both to the type of hemodynamic overload and to ventricular function.

Selective Upregulation of Cardiac Endothelin System in Patients With Ischemic but Not Idiopathic Dilated Cardiomyopathy: Endothelin-1 System in the Human Failing Heart

Only scarce information is available on the activity and modifications of the cardiac endothelin (ET)-1 system in heart failure due to ischemic (ICM) or idiopathic dilated (DCM) cardiomyopathy. The activity of the ET-1 system was investigated by measuring cardiac ET-1 and big ET-1 formation and quantifying cardiac mRNA for prepro-ET-1 (ppET-1), ET-converting enzyme-1, and ET(A) and ET(B) receptors both in myocardium and in isolated myocytes using Northern blot, reverse transcription-polymerase chain reaction, and in situ hybridization in 22 patients with DCM and 20 with ICM who underwent cardiac transplantation and in 7 potential heart transplant donors (nonfailing hearts). Notwithstanding a similar increase of plasma ET-1 in the 2 groups, cardiac ET formation, mRNA levels for ppET-1, and ET(A) and ET(B) receptors were higher on both the myocardium and isolated myocytes from ICM than on those from DCM hearts (P<0.001 for all). ppET-1 and ET-converting enzyme-1 mRNAs were expressed on myocytes and endothelial and interstitial cells in ICM, whereas in DCM and nonfailing hearts they were mainly expressed on nonmyocyte cells. In both ICM and DCM, the ET(A) mRNA signal was expressed on both myocytes and nonmyocyte cells, whereas ET(B) mRNA was almost exclusively localized on nonmyocyte cells. ET(A)- and ET(B)-specific receptor binding was increased on both myocytes and cardiac membranes, showing a positive correlation with left ventricular ejection fraction in ICM (r=0.78 and 0.70) but not in DCM patients. The present results show that human ventricular myocytes express all of the components of the ET-1 system, which is selectively upregulated in ICM patients and appears to be functionally important in the maintenance of cardiac function.

Different Growth Factor Activation in the Right and Left Ventricles in Experimental Volume Overload

Abstract—Mechanical factors play a key role in activation of cardiac growth factor response in hemodynamic overload, and both cooperate in myocardial remodeling. The present study was performed to investigate whether a different growth factor response is activated in the right and left ventricles in aortocaval fistula and its effects on regional myocardial adaptation. Relations between regional growth factor expression (angiotensin II, insulin-like growth factor-I, and endothelin-1), myocyte shape changes, and collagen deposition were investigated at mRNA and peptide levels in adult pigs after the creation of an aortocaval fistula distal to the renal arteries (n=15) and in sham-operated animals (n=15). The role of angiotensin II was investigated by the administration of angiotensin-converting enzyme inhibitor or angiotensin II receptor antagonist. In the left ventricle, pure volume overload was accompanied by persistent increase of insulin-like growth factor-I mRNA expression, peptide concentration (2.2-fold versus sham at 3 months, P <0.05), and significant increase of myocyte length (+29% at 3 months, P <0.05). Conversely, the mixed pressure-volume overload faced by the right ventricle resulted in significant regional overexpression of all growth factors investigated (angiotensin II, insulin-like growth factor-I, and endothelin-1), with corresponding increase of myocyte diameter and length and collagen deposition (+117% at 3 months). Collagen accumulation in the right ventricle as well as the increase in right ventricular end-diastolic pressure at the 3-month observation were inhibited by angiotensin II antagonism. The left and right ventricles respond differently to aortocaval fistula, and local growth factor expression is closely related to the regional myocardial adaptation.

Cardiac Angiotensin II Participates in Coronary Microvessel Inflammation of Unstable Angina and Strengthens the Immunomediated Component

Angiotensin (Ang) II is now recognized to be a mediator of a wide variety of inflammatory processes. This study investigated renin-angiotensin system (RAS) components and a number of inflammatory mediators in left ventricular biopsies from 2-vessel disease unstable angina (UA) (n=43) and stable angina (SA) (n=15) patients undergoing coronary bypass surgery. Biopsy samples from 6 patients undergoing valve replacement for mitral stenosis served as controls. UA patients were randomly assigned to angiotensin-converting enzyme (ACE)-inhibitor (ramipril), AT1 antagonist (valsartan), or placebo and treated during the 5 days preceding coronary bypass surgery, performed from 6 to 9 days after coronary angiography. During coronary angiography coronary blood flow was measured and samples were obtained from aorta and coronary sinus for determination of Ang I and Ang II gradients. The hearts of UA patients produced Ang II in a greater amount than in SA patients (P <0.01). UA biopsy samples showed numerous DR+ cells, identified as lymphocytes, macrophages, and endothelial cells. Reverse-transcriptase polymerase chain reaction showed overexpression of AGTN, ACE, and AT1-R genes, as well as upregulation of TNF-&agr;, IL-6, IFN-γ, and iNOS genes (P <0.01), with no differences between nonischemic and potentially ischemic areas. AGTN, ACE, and cytokine genes were mainly localized on endothelial cells. Ramipril and valsartan markedly decreased the expression levels of TNF-&agr;, IL-6, and iNOS, and, to a lesser extent, of IFN-γ genes, but did not affect the number of DR+ cells, with no significant difference between the 2 treatments. These results show that locally generated Ang II amplifies the immunomediated inflammatory process of coronary microvessels occurring in unstable angina.

Immunomediated and Ischemia-Independent Inflammation of Coronary Microvessels in Unstable Angina

Abstract— This study investigated whether the myocardium is involved in the acute inflammatory reaction associated with bursts of unstable angina (UA). We looked for the presence of activated DR+ inflammatory cells and the expression patterns, localization, and immunostaining identification of genes for cytokines (IL-1&bgr;, TNF-&agr;, IL-6, and IFN-&ggr;), MCP-1, and iNOS in the left ventricle biopsies from 2-vessel disease anginal patients, 24 with UA and 12 with stable angina (SA), who underwent coronary bypass surgery. Biopsy specimens from 6 patients with mitral stenosis who underwent valve replacement were examined as control hearts (CHs). Plasma levels of IL-2 soluble receptor (sIL-2R) were measured as a marker of systemic immune reaction. In CHs, DR+ cells were undetectable, and cytokine and iNOS mRNA expression were negligible. UA patients had higher sIL-2R levels than SA patients (P <0.01), and their biopsy specimens showed both numerous DR+ cells identified as lymphocytes, macrophages, endothelial cells, and elevated expression levels of cytokine and iNOS genes (from 2.4- to 6.1-fold vs SA; P <0.01). Cytokine and iNOS genes and proteins were localized in endothelial cells without involvement of myocytes. IL-1&bgr; and MCP-1 mRNAs were nearly undetectable. No significant differences were found in the number of DR+ cells, levels of cytokine, and iNOS genes between potentially ischemic and nonischemic left ventricle areas. In SA specimens, DR+ cells were very rare and only mRNAs for TNF-&agr; and iNOS genes were overexpressed versus CHs. These results indicated that an acute immunomediated inflammatory reaction, essentially involving coronary microvessels, is demonstrable in UA patients.

Renal resistive index early detects chronic tubulointerstitial nephropathy in normo- and hypertensive patients

Background: We studied whether the measurement of intrarenal vascular resistance by Doppler ultrasonography, capable of investigating renal interstitial compartment, allows the early detection of chronic tubulointerstitial nephropathy (TIN). Methods: 30 normotensive and 28 hypertensive (I-II OMS) patients with a clinical history suggestive of chronic TIN and normal renal function were enrolled. 40 healthy volunteers served as controls. Patients were considered TIN-negative or TIN-positive after investigating tubular function by urine concentrating and acidification tests. Renal sonographic parameters and renal resistive index (RRI) were obtained by duplex scanner. Glomerular filtration rate/effective renal plasmatic flow ratio was investigated by sequential renal scintigraphy in TIN-negative and TIN-positive patients; 99mTc-DMSA scintigraphy was also performed in TIN-positive patients. Results: RRI values of TIN-positive normotensive and hypertensive patients were significantly higher (p < 0.01 for both) than those of TIN-negative patients and of controls. RRI values resulted to be linearly related to uricemia (r = 0.88, p < 0.0001) only in normotensive patients. RRI values also resulted to be linearly related to filtration ratio values (r = 0.60, p < 0.0001). 99mTc-DMSA scintigraphy confirmed interstitial renal damage (grade 1 and 2). Conclusion: RRI measurement allows the early identification of both normotensive and hypertensive patients with chronic TIN and signs of tubular dysfunction, when renal function is still preserved.

Binding kinetics and antiplatelet activities of picotamide, a thromboxane A2 receptor antagonist.

1 Picotamide was shown to inhibit platelet binding of thromboxane A2 (TxA2)‐mimetics and to cause a reduction of TxA2 platelet receptors after in vivo administration. The present study aimed to investigate directly [3H]‐picotamide binding to human platelets and in particular the relationship between binding kinetics and antiaggregating properties. 2 [3H]‐picotamide time‐dependently bound to a single class of platelet TxA2 receptors with a KD of 325 nmol l−1 at equilibrium. The binding was displaceable by TxA2 analogues U46619 and ONO11120 (Ki 19 and 28 nmol l−1 respectively) but not by prostacyclin (PGI2), prostaglandin E2 (PGE2) and TxB2. Antiaggregating activity and TxA2 formation inhibition paralleled with binding kinetics. 3 By prolonging the incubation time from 30 to 120 min, picotamide showed a progressively increasing non‐displaceable binding, whereas specific displaceable binding decreased in comparison to the values reached at 30 min. Non displaceable binding was specific, temperature‐dependent, saturable and followed a Michaelis‐Menten kinetic (Vmaxapp = 130 fmol per 108 platelets h−1, KMapp = 330 nmol l−1). Picotamide progressively underwent a specific stable interaction with its platelet receptor. 4 In conclusion, after an initial reversible binding, a progressive stabilization of picotamide binding takes place resulting in a progressively more stable interaction with platelets.

Impairment of cardiopulmonary receptor sensitivity in the early phase of heart failure

Objectives: To characterise the efficiency of the cardiopulmonary baroreflex system in the early phase of heart failure and its relation to limitation of physical activity. Design: Forearm blood flow (venous occlusion plethysmography), vascular resistance, and central venous pressure (CVP), estimated from an antecubital vein, were measured in the supine position at baseline and 15 minutes after application of lower body negative pressure at −7 and −14 mm Hg (receptor downloading) or leg raising (receptor loading). Subjects: Heart failure patients without limitation (NYHA class I; n  =  18) or with slight limitation of physical activity (NYHA class II; n  =  13), and 11 healthy controls. Results: The efficiency of the cardiopulmonary baroreflex function, expressed by the slope of the relation between CVP changes and the corresponding changes of calculated forearm vascular resistance (gain), was reduced both in NYHA class I patients (mean (SD) −1.99 (0.83) v −2.78 (0.66) in controls; p < 0.05) and NYHA class II patients (−1.29 (0.5); p<0.001 v controls). However, change in peripheral vascular resistance during preload increase was similar in controls (−3.3 (0.9) units) and in NYHA class I patients (−3.3 (2.1) units; NS v controls), and was significantly reduced only in NYHA class II patients (−1.6 (1.3) units, p < 0.03 v controls). The gain in the cardiopulmonary reflex was related to the distance walked during the six minute corridor test. Conclusions: A reduced tonic efficacy of the cardiopulmonary reflex system is already detectable in the early phase of heart failure, the impairment in acute response to preload increase being detectable only in symptomatic patients.

Increased renal endothelin formation is associated with sodium retention and increased free water clearance

To investigate whether renal endothelin (ET)-1 participates in water and sodium handling, we investigated the influence of different sodium intakes on renal production of ET-1 in eight healthy subjects. The functional relationship with the renin-angiotensin system was also studied. Renal ET-1 formation is affected by sodium intake, because 1 wk of high sodium decreased urinary ET-1 excretion (-34%, P < 0.05), whereas a low-sodium diet increased ET-1 excretion (66%, P < 0.05) and mRNA expression for preproendothelin-1 in epithelial cells of medullary collecting ducts and endothelial cells of the peritubular capillary network. Increased ET-1 renal synthesis was associated with sodium retention and increased free water clearance. Urinary ET-1 excretion changes from normal to low-sodium diet were negatively related to contemporary changes in sodium excretion (r = 0.97, P < 0.05) and were positively correlated with free water clearance (r = 0.97, P < 0.05). These correlations were maintained during angiotensin-converting enzyme inhibition, which only partially reduced ET-1 renal excretion. These results indicate that renal ET-1 production is indeed modulated by varying sodium intakes and may exert a role in sodium and water handling.To investigate whether renal endothelin (ET)-1 participates in water and sodium handling, we investigated the influence of different sodium intakes on renal production of ET-1 in eight healthy subjects. The functional relationship with the renin-angiotensin system was also studied. Renal ET-1 formation is affected by sodium intake, because 1 wk of high sodium decreased urinary ET-1 excretion (-34%, P< 0.05), whereas a low-sodium diet increased ET-1 excretion (66%, P < 0.05) and mRNA expression for preproendothelin-1 in epithelial cells of medullary collecting ducts and endothelial cells of the peritubular capillary network. Increased ET-1 renal synthesis was associated with sodium retention and increased free water clearance. Urinary ET-1 excretion changes from normal to low-sodium diet were negatively related to contemporary changes in sodium excretion ( r = 0.97, P < 0.05) and were positively correlated with free water clearance ( r = 0.97, P < 0.05). These correlations were maintained during angiotensin-converting enzyme inhibition, which only partially reduced ET-1 renal excretion. These results indicate that renal ET-1 production is indeed modulated by varying sodium intakes and may exert a role in sodium and water handling.

Adherence to antihypertensive therapy affects Ambulatory Arterial Stiffness Index

BACKGROUND A major contributor to poor blood pressure (BP) control is nonadherence to therapy, which remains poorly recognized by physicians. The prevention of hypertension-induced changes in arterial wall, namely increased arterial stiffness and peripheral vascular resistance, is a reasoned adequate end-point of hypertension treatment. Indirect measurement of these arterial factors can be derived from the analysis of 24-hour Ambulatory BP Monitoring (24 h-ABPM). This pilot study evaluated the association between antihypertensive therapy adherence and 24 h-ABPM-derived parameters in hypertensive patients. METHODS We studied 42 hypertensive patients (70±10 years) in chronic antihypertensive therapy. Patients were divided according to the Morisky Medication Adherence Scale (MMAS) in Low-Adher (MMAS <6) and High-Adher (MMAS 6-8) groups. The Ambulatory Arterial Stiffness Index (AASI) and its symmetric calculation (Sym_AASI) were derived from 24 h-ABPM. A bivariate logistic regression analysis was performed to evaluate the predictive value of MMAS for increased AASIs (i.e. above the median). RESULTS Low-Adher group (n=17) showed higher AASIs compared to High-Adher group (n=25). The two groups were similar in terms of BP burden at the 24 h-ABPM. AASIs were inversely related to MMAS. MMAS resulted a predictor for both increased AASI (O.R. 0.49, 95% CI 0.31-0.76, P<0.01) and increased Sym_AASI (O.R. 0.67, 95% CI 0.47-0.95, P=0.026). After adjustment for PP, age and nocturnal diastolic BP reduction, MMAS persisted as an inverse predictor only of increased AASI. MMAS was also related to the diastolic vs systolic BP correlation coefficient r. CONCLUSIONS Low adherence to antihypertensive therapy seems to be associated with increased standard AASI. In this setting, AASI could represent an additional information derived from the 24 h-ABPM in hypertensive patient evaluation.