Roberta Paliotti

Different effects of antihypertensive therapies based on losartan or atenolol on ultrasound and biochemical markers of myocardial fibrosis: results of a randomized trial.

Background—In hypertensive left ventricular hypertrophy (LVH), myocardial texture is altered by a disproportionate increase in fibrosis, but there is insufficient clinical evidence whether antihypertensive therapy or individual agents can induce regression of myocardial fibrosis. Methods and Results—We compared the effects of an angiotensin II receptor antagonist with a &bgr;-blocker on myocardial collagen volume (assessed by echoreflectivity and serum collagen markers) in 219 hypertensive patients with echocardiographically documented LVH. Patients were allocated randomly to receive losartan 50 to 100 mg/d (n=111) or atenolol 50 to 100 mg/d (n=99) with or without hydrochlorothiazide 12.5 to 25 mg/d for 36 weeks. Echoreflectivity analysis was conducted on ultrasound tracings of the midapex septum with specifically designed and validated software. A color histogram of reflecting echoes was obtained, and its spread (broadband [BB], previously shown to correlate directly with collagen volume fraction on endomyocardial biopsies) was used as the primary outcome measure. Mean color scale and serum markers of collagen synthesis (PIP, PIIIP) or degradation (CITP) were secondary outcome variables. Echoreflectivity analysis proved feasible in 106 patients (losartan 52, atenolol 54). Losartan reduced BB over 36 weeks (from 114.5 to 104.3 color levels, P<0.02), whereas atenolol treatment was associated with an increase in BB (from 109.0 to 113.6 color levels, P=NS), the difference between treatments being −12.8 color levels (95% CI −23.6 to −2.0, P=0.02). Secondary end points (mean color scale and collagen markers) also changed in the direction of decreased collagen in patients receiving losartan, but differences between groups were not statistically significant. Conclusions—In hypertensive patients with LVH, losartan decreases myocardial collagen content, whereas atenolol does not. The difference between the 2 treatments is statistically significant.

Blood pressure-independent cardiac hypertrophy in acromegalic patients.

OBJECTIVE Acromegaly is frequently associated with an increase in left ventricular mass, even in the absence of systemic hypertension. Pathological studies on acromegalic hearts have shown an extensive interstitial fibrosis, suggesting the existence of a specific acromegalic cardiomyopathy. The aim of this study was to assess left ventricular wall structure in acromegaly by ultrasonic tissue characterization. DESIGN AND METHODS We studied 10 untreated acromegalic patients and 10 age-matched healthy control subjects. The echo patterns of two-dimensional long-axis end-diastolic echocardiograms were assessed by colour-scale analysis of the interventricular septum, with estimates of the mean colour scale value, the broad band (Bb) and the derived collagen volume fraction (dCVF). We also measured electrocardiographic QT interval dispersion (QTd) as a marker of dyshomogeneous ventricular repolarization. RESULTS Seven patients had left ventricular hypertrophy according to the sex-independent criteria; of these, two had arterial hypertension. None of our patients had echocardiographic evidence of diastolic or systolic dysfunction. All patients showed significantly increased myocardial echoreflectivity (Bb = 106.4+/-12.1 versus 79.3+/-6.5; dCVF% = 2.78+/-0.53 versus 1.58+/-0.29; P < 0.0001) and QTd (66+/-13 ms versus 54+/-8 ms, P < 0.05). A significant correlation was found between dCVF and the duration of acromegaly (r = 0.80; P = 0.005). CONCLUSIONS Left ventricular remodelling observed in acromegaly is not related to the presence of arterial hypertension; we hypothesize that the increased echoreflectivity and QTd are long-term consequences of cardiac hypertrophy and prolonged exposure to high levels of growth hormone and insulin-like growth factor-I.

Assessment of carotid plaque composition in hypertensive patients by ultrasonic tissue characterization: a validation study

Objective Ultrasonic tissue characterization of epi-aortic vessels may be useful to define the composition of atherosclerotic plaques. Videodensitometry provides a histogram representing the frequency distribution of gray levels corresponding to different compositions of the carotid wall. However, lack of standardization limits the clinical application of this technique. In the present study, the echoreflectivity (ER) pattern of atherosclerotic plaques in vivo was compared with their histological pattern after surgical removal, and the reproducibility of measurement was tested. Design and methods We studied 19 hypertensive patients with a carotid artery stenosis ⩾ 70%, eligible for carotid thromboendarterectomy (TEA). Before TEA, all patients underwent standard high-resolution B-mode carotid ultrasound. ER parameters (mean gray level, broad band, skewness, and kurtosis) were obtained in a region of interest selected along the whole plaque, between the intima–blood and the media–adventitia interfaces. The plaques removed during TEA were examined by a histologist and classified into three groups on the basis of fibrous tissue (FT) content: lipidic (FT < 20%), fibrolipidic (20 ⩽ FT ⩽ 50%), and fibrous (FT > 50%). Discriminant function analysis was used to evaluate classification efficacy of different histological groups based on ER parameters. Results Histologically, five lesions were classified as lipidic, six as fibrolipidic and eight as fibrous. Analysis of variance showed significant between group differences in all ER parameters. The combined use of all ER parameters provided correct classification of plaques in 94.73% of cases (P < 0.0001), improving the classification made using single parameters. Intra-observer and inter-observer variabilities (Bland–Altman method) of mean gray level measurements were small. Conclusions Videodensitometry can discriminate between tissue composition of carotid lesions and complement the quantitative assessment of intima–media thickness by additionally providing a well-reproducible semiquantitative evaluation of vascular wall constituents.

Carotid wall composition in hypertensive patients after 4-year treatment with lacidipine or atenolol: an echoreflectivity study.

Objective In the European Lacidipine Study on Atherosclerosis (ELSA), against a similar antihypertensive effect, a significantly greater effect of lacidipine was found on carotid intima–media thickness (IMT) progression, indicating a specific anti-atherosclerotic effect of lacidipine. However, not only the extent but also the composition of an atherosclerotic plaque is a determinant of subsequent events. Design and methods Among the 2334 patients enrolled in ELSA, 420 with 4-year treatment were chosen, videodensitometric analysis of their ultrasound carotid scan was performed and the maximum wall lesion (Tmax) was classified as lipidic, fibrolipidic and fibrotic by means of software previously validated against histology. Of the 420 patients, 244 had scans suitable for videodensitometry. Results Excellent reproducibility of videodensitometry analysis was found using the Bland–Altman and other methods. At baseline, ELSA hypertensive patients had predominantly fibrolipidic walls (70%), with an echoreflectivity indicating a mean collagen content of 25%. After 4 years of antihypertensive treatment, little change in the frequency distribution of carotid lesions (fibrolipidic 73%) was found, with no significant differences between patients randomized to lacidipine or atenolol. Conclusions Our study provides previously unavailable information that carotid wall composition changes to an extremely small extent during 4-year effective blood pressure lowering. With lacidipine, stable composition is associated with a lower IMT progression than with atenolol.

Endothelial Colony Forming Capacity is Related to C-Reactive Protein Levels in Healthy Subjects

The majority of clinical studies on endothelial progenitor cells (EPCs) focuses on the role of these cells in cardiovascular diseases and no systematic studies exist regarding their variations in healthy subjects. In order to define the burden of angiogenesis in physiological conditions we assessed the frequency of peripheral blood endothelial colonies (PB-ECs) and their relation with other factors possibly involved in their function such as high-sensitivity C-reactive protein (hs-CRP), endothelial cell-specific mitogen factor (VEGF) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in a highly selected healthy population. A PB sample was obtained from 37/47 healthy subjects (age 40.2+/-15.0yrs; M/F 15/22) without known cardiovascular risk factors. The serum level of hs-CRP, VEGF, TIMP-1, the frequency of PB-ECs by clonogenic assay, and the number of early EPCs and late EPCs by flow cytometry analysis were evaluated. PB-ECs were formed by 40.5% of studied subjects with a mean of 0.40+/-0.82 colonies/10(6) cells. The differences in the frequency of colony formation between genders were not statistically significant. The subjects with PB-ECs were characterized by higher values of hs-CRP, when compared with those not forming colonies, 0.276+/-0.230 vs 0.095+/-0.077 mg/l (p=0.003) respectively, and of VEGF, 328.3+/-162.9 vs 202.68+/-118.53 pg/ml (p=0.02). No significant differences were found in TIMP-1 values. The EPC clonogenic potential seems to be related to hs-CRP and VEGF levels even in healthy population supporting the concept that these mediators are involved in physiological ECs function.

Effects of Thyroid Hormones on Cardiac Structure: A Tissue Characterization Study in Patients with Thyroid Disorders Before and After Treatment

Experimental evidence suggests an involvement of thyroid hormones in myocardial nonmyocyte component growth. We evaluated the possible role of thyroid hormones in myocardial remodeling by ultrasonic tissue characterization (videodensitometry) in 8 hyperthyroid patients, in 10 hypothyroid patients, and in 2 patients with thyroid hormone resistance syndrome (RTH), before, 60, and 120 days after treatment (T0, T60, T120), and in 10 age-matched euthyroids. According to a previously described procedure, the derived collagen volume fraction (dCVF%, an echocardiographic index estimating the collagen content) was predicted from the pixel-level frequency distribution width (broadband, Bb) of the selected echocardiographic images. Thyrotropin (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) were assessed by immunometric method. QT interval dispersion (QTd) on basal electrocardiogram was measured as a marker of dyshomogeneous ventricular repolarization. At T0, Bb and dCVF% were normal in hyperthyroid and euthyroid patients, and slightly increased in RTH patients, whereas significantly higher values were found in hypothyroids. At T60, a significant reduction in Bb was observed in hypothyroids, with nearly normal dCVF% values. This trend was confirmed at T120 with complete normalization of echoreflectivity. No echoreflectivity changes were observed in hyperthyroid and RTH patients during treatment. QTd was significantly increased in hypothyroids at T0, while no significant differences were found among groups at T60 and T120. Because the different videodeonsitometric myocardial properties observed in hypothyroid versus hyperthyroid patients correspond to an increase of dCVF%, this study suggests that thyroid hormones exert an inhibitory effect on myocardial collagen synthesis in humans.

Beneficial effects of treatment with transglutaminase inhibitor cystamine on the severity of inflammation in a rat model of inflammatory bowel disease.

Inflammatory bowel disease (IBD) represents a socially and clinically relevant disorder, characterized by intestinal chronic inflammation. Cystamine (CysN) is a multipotent molecule with healthy effects and, moreover, it is an inhibitor of transglutaminases (TGs), including the TG type 2 (TG2), an enzyme with pleiotropic functions, involved in different pathways of inflammation and central in the pathogenesis of some human disorders as the IBD. Our aim was to evaluate the effect of CysN in an IBD rat model. A total of 30 rats were divided into 4 groups: controls without treatment (CTR; n=7); receiving the 2,4,6-trinitrobenzene sulfonic acid enema (TNBS group; n=8); treated with TNBS enema plus oral CysN (TNBS–CysN group; n=8); treated with CysN (CysN group; n=7). After killing, bowel inflammation was evaluated applying specific scores. TG activity, TG2 and isopeptide bond immunohistochemical expression, and tumor necrosis factor-α (TNF-α) were evaluated in the colonic tissue, such as interleukin-6 (IL-6) serological levels (ELISA). TG2 was also evaluated on the luminal side of the colon by immunoautoradiography. Colonic samples from IBD patients were compared with animal results. TNBS–CysN group developed a less severe colitis compared with the TNBS group (macroscopic score 0.43±0.78 vs 3.28±0.95, microscopic score 6.62±12.01 vs 19.25±6.04, P<0.05, respectively) associated with a decrease of TG activity, TG2 and isopeptide bond immunohistochemical expression, TNF-α and IL-6 levels. No statistically significant differences were found between CysN and CTR groups. The colonic immunolocalization of TG2 was comparable in humans affected by IBD and TNBS-administered animals. This is the first demonstration that treatment with a CysN has an anti-inflammatory effect, reducing severity of colitis in a rat model. CysN could be tested as a possible treatment or co-treatment in IBD therapeutic trials.

Effects of antihypertensive treatment on ultrasound measures of myocardial fibrosis in hypertensive patients with left ventricular hypertrophy: results of a randomized trial comparing the angiotensin receptor antagonist, candesartan and the angiotensin-converting enzyme inhibitor, enalapril

Objective To compare the effects of the angiotensin II receptor antagonist candesartan with the angiotensin-converting enzyme inhibitor enalapril on myocardial fibrosis evaluated by echoreflectivity analysis. Methods Hypertensive patients (n = 196) with echocardigraphically documented left ventricular hypertrophy were randomized to candesartan 8–16 mg/day (n = 91) or enalapril 10–20 mg/day (n = 105) with possible addition of hydrochlorothiazide (12.5–25 mg/day) for 48 weeks. Echoreflectivity analysis was performed on ultrasound two-dimensional tracings of the midapex septum with a specifically designed and validated software. Colour histograms were obtained; the primary outcome variable was the treatment-related change in histogram width (broadband), previously shown to correlate with collagen volume on endomyocardial biopsy; changes in mean colour scale were secondary outcome variable. Results Echoreflectivity analysis was feasible in 84 patients (48 candesartan, 36 enalapril). Broadband decreased significantly in the candesartan (−8.0 colour levels) and in the enalapril group (−12.9 colour levels) with no significant difference between treatments (P = 0.409); no significant changes occurred in mean colour scale. Patients under monotherapy (n = 46) showed similar trends as the larger intention to treat cohort, without significant difference between treatments. Conclusion In hypertensive patients with left ventricular hypertrophy, both candesartan and enalapril induce a moderate but statistically significant reduction in an echoreflectivity index of myocardial fibrosis.

Potential advantages of cell administration on the inflammatory response compared to standard ACE inhibitor treatment in experimental myocardial infarction

BackgroundBone Marrow (BM) progenitor cells can target the site of myocardial injury, contributing to tissue repair by neovascolarization and/or by a possible direct paracrine effect on the inflammatory cascade. Angiotensin Converting Enzyme inhibitors (ACE-I) are effective in reducing mortality and preventing left ventricular (LV) function deterioration after myocardial infarction.MethodsWe investigated the short term effects of BM mononuclear cells (BMMNCs) therapy on the pro-inflammatory cytokines (pro-CKs) and on LV remodelling and compared these effects over a standard ACE-I therapy in a rat model of myocardial cryodamage.Forty two adult inbread Fisher-F344 rats were randomized into three groups: untreated (UT; n = 12), pharmacological therapy (ACE-I; n = 14, receiving quinapril), and cellular therapy (BMMNCs; n = 16, receiving BMMNCs infusion). Rats underwent to a standard echocardiogram in the acute setting and 14 days after the damage, before the sacrifice. Pro-CKs analysis (interleukin (IL)1β, IL-6, tumor necrosis factor (TNF)α was performed (multiplex proteome arrays) on blood samples obtained by direct aorta puncture before the sacrifice; a control group of 6 rats was considered as reference.ResultsConcerning the extension of the infarcted area as well as the LV dimensions, no differences were observed among the animal groups; treated rats had lower left atrial diameters and higher indexes of LV function. Pro-Cks were increased in infarcted-UT rats if compared with controls, and significantly reduced by BMMNCs and ACE-I ; TNFα inversely correlated with LV fractional shortening.ConclusionAfter myocardial infarction, both BMMNCs and ACE-I reduce the pattern of pro-Ck response, probably contributing to prevent the deterioration of LV function observed in UT rats.

Effects of simulated altitude (normobaric hypoxia) on cardiorespiratory parameters and circulating endothelial precursors in healthy subjects

BackgroundCirculating Endothelial Precursors (PB-EPCs) are involved in the maintenance of the endothelial compartment being promptly mobilized after injuries of the vascular endothelium, but the effects of a brief normobaric hypoxia on PB-EPCs in healthy subjects are scarcely studied.MethodsClinical and molecular parameters were investigated in healthy subjects (n = 8) in basal conditions (T0) and after 1 h of normobaric hypoxia (T1), with Inspiratory Fraction of Oxygen set at 11.2% simulating 4850 mt of altitude. Blood samples were obtained at T0 and T1, as well as 7 days after hypoxia (T2).ResultsIn all studied subjects we observed a prompt and significant increase in PB-EPCs, with a return to basal value at T2. The induction of hypoxia was confirmed by Alveolar Oxygen Partial Pressure (PAO2) and Spot Oxygen Saturation decreases. Heart rate increased, but arterial pressure and respiratory response were unaffected. The change in PB-EPCs percent from T0 to T1 was inversely related to PAO2 at T1. Rapid (T1) increases in serum levels of hepatocyte growth factor and erythropoietin, as well as in cellular PB-EPCs-expression of Hypoxia Inducible Factor-1α were observed.ConclusionIn conclusion, the endothelial compartment seems quite responsive to standardized brief hypoxia, possibly important for PB-EPCs activation and recruitment.