Stella Bernardi

Genetic Ace2 deficiency accentuates vascular inflammation and atherosclerosis in the ApoE knockout mouse.

Rationale: Angiotensin-converting enzyme (ACE)2 opposes the actions of angiotensin (Ang) II by degrading it to Ang 1-7. Objective: Given the important role of Ang II/Ang 1-7 in atherogenesis, we investigated the impact of ACE2 deficiency on the development of atherosclerosis. Methods and Results: C57Bl6, Ace2 knockout (KO), apolipoprotein E (ApoE) KO and ApoE/Ace2 double KO mice were followed until 30 weeks of age. Plaque accumulation was increased in ApoE/Ace2 double KO mice when compared to ApoE KO mice. This was associated with increased expression of adhesion molecules and inflammatory cytokines, including interleukin-6, monocyte chemoattractant protein-1, and vascular cell adhesion molecule-1, and an early increase in white cell adhesion across the whole aortae on dynamic flow assay. In the absence of a proatherosclerotic (ApoE KO) genotype, ACE2 deficiency was also associated with increased expression of these markers, suggesting that these differences were not an epiphenomenon. ACE inhibition prevented increases of these markers and atherogenesis in ApoE/ACE2 double KO mice. Bone marrow macrophages isolated from Ace2 KO mice showed increased proinflammatory responsiveness to lipopolysaccharide and Ang II when compared to macrophages isolated from C57Bl6 mice. Endothelial cells isolated from Ace2 KO mice also showed increased basal activation and elevated inflammatory responsiveness to TNF-&agr;. Similarly, selective inhibition of ACE2 with MLN-4760 also resulted in a proinflammatory phenotype with a physiological response similar to that observed with exogenous Ang II (10−7 mol/L). Conclusions: Genetic Ace2 deficiency is associated with upregulation of putative mediators of atherogenesis and enhances responsiveness to proinflammatory stimuli. In atherosclerosis-prone ApoE KO mice, these changes potentially contribute to increased plaque accumulation. These findings emphasize the potential utility of ACE2 repletion as a strategy to reduce atherosclerosis.

Non-alcoholic fatty liver disease is associated with left ventricular diastolic dysfunction in essential hypertension

BACKGROUND AND AIM Insulin resistance is recognized as the pathophysiological hallmark of non-alcoholic fatty liver disease (NAFLD). A relation between insulin sensitivity and left ventricular morphology and function has been reported in essential hypertension, where a high prevalence of NAFLD has been recently found. We investigated the inter-relationship between left ventricular morphology/function, metabolic parameters and NAFLD in 86 never-treated essential hypertensive patients subdivided in two subgroups according to the presence (n = 48) or absence (n = 38) of NAFLD at ultrasonography. METHODS AND RESULTS The two groups were similar as to sex, age and blood pressure levels. No patient had diabetes mellitus, obesity, hyperlipidemia, or other risk factors for liver disease. Body mass index, waist circumference, triglycerides, glucose, insulin, homeostasis model of assessment index for insulin resistance (HOMA-IR), aspartate aminotransferase and alanine aminotransferase were higher and adiponectin levels were lower in patients with NAFLD than in patients without NAFLD, and were associated with NAFLD at univariate analysis. Patients with NAFLD had similar prevalence of left ventricular hypertrophy compared to patients without NAFLD, but a higher prevalence of diastolic dysfunction (62.5 vs 21.1%, P < 0.001), as defined by E/A ratio <1 and E-wave deceleration time >220 ms. Diastolic dysfunction (P = 0.040) and HOMA-IR (P = 0.012) remained independently associated with NAFLD at backward multivariate analysis. CONCLUSIONS Non-alcoholic fatty liver disease was associated with insulin resistance and abnormalities of left ventricular diastolic function in a cohort of patients with essential hypertension, suggesting a concomitant increase of metabolic and cardiac risk in this condition.

Angiotensin-converting enzyme 2 is a key modulator of the renin–angiotensin system in cardiovascular and renal disease

Purpose of reviewAngiotensin-converting enzyme 2 (ACE2) has recently emerged as a key regulator of the renin–angiotensin system in both health and disease. Recent findingsACE2 deficiency is associated with elevated tissue and circulating levels of angiotensin II and reduced levels of angiotensin 1–7. Phenotypically, this results in a modest elevation in systolic blood pressure and left ventricular hypertrophy. In atherosclerosis-prone apolipoprotein E knockout mice, ACE2 deficiency results in augmented vascular inflammation and an inflammatory response that contributes to increased atherosclerotic plaque formation. In the kidney, ACE2 deficiency is associated with progressive glomerulosclerosis. Interventions such as ACE2 replenishment or augmentation of its actions have proven successful in reducing hypertension, plaque accumulation, and renal and cardiac damage in a range of different models. Although promising, the balance of the renin–angiotensin system remains complicated, with some evidence that overexpression of ACE2 may have adverse cardiac effects, and ACE2 and its metabolic products may promote epithelial-to-mesenchymal transition. SummaryRepletion of ACE2s activities offers a new strategy to complement current clinical interventions in treating hypertension, renal and cardiovascular disease. In particular conditions where ACE inhibition and angiotensin receptor blockade are partially effective, the adjunctive actions of ACE2 may not only reduce clinical escape but also augment the efficacy of interventions.

Radiofrequency Ablation Compared to Surgery for the Treatment of Benign Thyroid Nodules

Objective. Benign thyroid nodules are a common occurrence whose only remedy, in case of symptoms, has always been surgery until the advent of new techniques, such as radiofrequency ablation (RFA). This study aimed at evaluating RFA efficacy, tolerability, and costs and comparing them to hemithyroidectomy for the treatment of benign thyroid nodules. Design and Methods. 37 patients who underwent RFA were retrospectively compared to 74 patients surgically treated, either in a standard inpatient or in a short-stay surgical regimen. Efficacy, tolerability, and costs were compared. The contribution of final pathology was also taken into account. Results. RFA reduced nodular volume by 70% after 12 months and it was an effective method for treating nodule-related clinical problems, but it was not as effective as surgery for the treatment of hot nodules. RFA and surgery were both safe, although RFA had less complications and pain was rare. RFA costed €1,661.50, surgery costed €4,556.30, and short-stay surgery costed €4,139.40 per patient. RFA, however, did not allow for any pathologic analysis of the nodules, which, in 6 patients who had undergone surgery (8%), revealed that the nodules harboured malignant cells. Conclusions. RFA might transform our approach to benign thyroid nodules.

Cell-based therapies for diabetic complications

In recent years, accumulating experimental evidence supports the notion that diabetic patients may greatly benefit from cell-based therapies, which include the use of adult stem and/or progenitor cells. In particular, mesenchymal stem cells and the circulating pool of endothelial progenitor cells have so far been the most studied populations of cells proposed for the treatment of vascular complications affecting diabetic patients. We review the evidence supporting their use in this setting, the therapeutic benefits that these cells have shown so far as well as the challenges that cell-based therapies in diabetic complications put out.

Human Full-Length Osteoprotegerin Induces the Proliferation of Rodent Vascular Smooth Muscle Cells both in vitro and in vivo

Background/Aims: Since elevated plasma levels of osteoprotegerin (OPG) represent a risk factor for death and heart failure in patients affected by diabetes mellitus and coronary artery disease, this study aimed to elucidate potential roles of OPG in the pathogenesis of atherosclerosis. Methods and Results: Recombinant human full-length OPG, used at concentrations comparable to the elevated levels found in the serum of diabetic patients, significantly increased the proliferation rate of rodent vascular smooth muscle cells (VSMC). To mimic the moderate chronic elevation of OPG observed in diabetic patients, low doses (1 µg/mouse) of full-length human OPG were injected intraperitoneally every 3 weeks in diabetic apolipoprotein E (apoE)-null mice. The group of animals treated for 12 weeks with recombinant OPG showed a small increase in the total aortic plaque area at necropsy in comparison to vehicle-treated animals. Importantly, while no differences in the amount of interstitial collagen or the degree of macrophage infiltration were observed between OPG-treated and vehicle-treated apoE-null diabetic animals, a significant increase in the number of α-actin-positive smooth muscle cells was observed in the plaques of OPG-treated mice. Conclusions: Our data suggest that OPG promotes VSMC proliferation and might be directly involved in pathogenetic aspects of atherosclerosis.

TNF-related apoptosis-inducing ligand significantly attenuates metabolic abnormalities in high-fat-fed mice reducing adiposity and systemic inflammation.

TRAIL [TNF (tumour necrosis factor)-related apoptosis-inducing ligand] has recently been shown to ameliorate the natural history of DM (diabetes mellitus). It has not been determined yet whether systemic TRAIL delivery would prevent the metabolic abnormalities due to an HFD [HF (high-fat) diet]. For this purpose, 27 male C57bl6 mice aged 8 weeks were randomly fed on a standard diet, HFD or HFD+TRAIL for 12 weeks. TRAIL was delivered weekly by intraperitoneal injection. Body composition was evaluated; indirect calorimetry studies, GTT (glucose tolerance test) and ITT (insulin tolerance test) were performed. Pro-inflammatory cytokines, together with adipose tissue gene expression and apoptosis, were measured. TRAIL treatment reduced significantly the increased adiposity associated with an HFD. Moreover, it reduced significantly hyperglycaemia and hyperinsulinaemia during a GTT and it improved significantly the peripheral response to insulin. TRAIL reversed the changes in substrate utilization induced by the HFD and ameliorated skeletal muscle non-esterified fatty acids oxidation rate. This was associated with a significant reduction of pro-inflammatory cytokines together with a modulation of adipose tissue gene expression and apoptosis. These findings shed light on the possible anti-adipogenic and anti-inflammatory effects of TRAIL and open new therapeutic possibilities against obesity, systemic inflammation and T2DM (Type 2 DM).

High-salt diet increases glomerular ACE/ACE2 ratio leading to oxidative stress and kidney damage

BACKGROUND Angiotensin II (AngII) contributes to salt-driven kidney damage. In this study, we aimed at investigating whether and how the renal damage associated with a high-salt diet could result from changes in the ratio between angiotensin-converting enzyme (ACE) and angiotensin-converting enzyme 2 (ACE2). METHODS Forty-eight rats randomly allocated to three different dietary contents of salt were studied for 4 weeks after undergoing a left uninephrectomy. We focussed on kidney functional, structural and molecular changes. At the same time, we studied kidney molecular changes in 20 weeks old Ace2-knockout mice (Ace2KO), with and without ACE inhibition. RESULTS A high salt content diet significantly increased the glomerular ACE/ACE2 ratio. This was associated with increased oxidative stress. To assess whether these events were related, we measured renal oxidative stress in Ace2KO, and found that the absence of ACE2 promoted oxidative stress, which could be prevented by ACE inhibition. CONCLUSION One of the mechanisms by which a high-salt diet leads to renal damage seems to be the modulation of the ACE/ACE2 ratio which in turn is critical for the cause of oxidative stress, through AngII.

Osteoprotegerin induces morphological and functional alterations in mouse pancreatic islets

Although serum osteoprotegerin (OPG) is significantly increased in diabetic subjects, its potential role in beta cell dysfunction has not been investigated. This study aimed to assess the effect of full-length OPG administered in vivo in mice on pancreatic islet structure and function and its interaction with the renin-angiotensin system (RAS). OPG-treated mice showed increased islet monocyte/macrophage infiltration, fibrosis and apoptosis with reduction of islet function. The remodeling of islet architecture was associated with increased pancreatic expression of components of the RAS, growth factor genes (transforming growth factor β and connective tissue growth factor) and inflammatory molecules (monocyte chemotactic protein-1 and vascular adhesion molecule type 1). Prevention of these changes with improvement of insulin secretion was observed in ramipril treated animals. Our data suggest that OPG might play an important role in promoting beta cell dysfunction and that the upregulation of the local RAS represents one possible mechanism responsible for the OPG-induced beta cell dysfunction.

State of Art and Recent Developments of Anti-Cancer Strategies Based on TRAIL

Multicellular organisms require apoptosis whereby the human body eliminates unnecessary and/or damaged cells. Apoptosis, or programmed cell death, can indeed be considered as a constitutive anti-cancer mechanism that seems to be defective in more than 50% of cancers. Molecular insights on the biology of the apoptotic process have led to the development of new anti-cancer strategies aiming at recovering and stimulating this process. Preclinical and clinical studies of our and other groups have demonstrated that targeting the extrinsic apoptotic pathway by various death receptors agonists is a safe and effective anti-cancer strategy, which thus may become a new cornerstone of cancer therapy. Here, we review the most recent acquisitions and patents on TRAIL or TRAIL mimetics, as well as the combination therapies that could be used with them.