Effetto del blocco del recettore AT1R dell'angiotensina II sullo stress ossidativo e sul signalling mediato dallo stress ossidativo nel danno cardiovascolare ed endoteliale del paziente iperteso. Studio ex vivo nell'uomo con approccio biologico molecolare

High blood pressure is a major risk factor for cardiovascular disease, myocardial infarction, heart failure, kidney failure and peripheral vascular disease. Oxidative stress, due to increased production of reactive oxygen species (ROS), plays an important pathophysiological role in the development of hypertension and its long-term complications, such as cardiovascular remodeling and atherosclerosis (Touyz RM et al, 2004). Various risk factors (smoking, diabetes, increased LDL, as well as hypertension) lead to an increase of the redox state, resulting in endothelial dysfunction, increased expression of pro-inflammatory redox sensitive genes and activation of smooth muscle cells (Luft FC, 2001). In hypertensive patients, the Renin-Angiotensin-Aldosterone system (RAAS) is activated and this causes an increase of Angiotensin (Ang II) production (Ruster C et al, 2006). Ang II causes vasoconstriction, increases total peripheral resistance and, consequently, blood pressure but at the same time strongly induces oxidative stress. Ang II mediates its actions through two distinct receptors: AT1R (for which Ang II has more affinity) and AT2R (Dihn DT et al, 2001; Mehta PK et al, 2007; Calò LA et al, 2010). Many of the Ang II-related events are mediated via activation of the AT1R receptor followed by both a short term signaling, which causes vasoconstriction, and a long term signaling, which leads to vascular remodeling and atherosclerosis through the activation of NAPDH oxidase and consequently production of superoxide anion (O2-) (Griendling KK et al, 2000). Ang II signaling via AT2R stimulation has been suggested to counteract many actions mediated by AT1R inducing vasodilatation, anti-proliferation, cell differentiation, anti-apoptotic signals; it therefore has a role in the homeostatic counterbalance of an excessive stimulation of AT1R (Volpe et al, 2003; Zhuo et al, 2008; Yamamoto et al, 2008). Oxidative stress is well recognized to play a crucial role in the pathogenic mechanisms of endothelial dysfunction. Endothelial dysfunction defines a complex molecular and biochemical picture of inflammatory, proliferative, structural and functional abnormalities of the vasculature. Endothelial progenitor cells (EPCs), derived from bone marrow, play an important role for the protection from these abnormalities (Hill JM et al, 2003), as they are able to repair the damaged endothelium, through a continuous process of re-endothelialization and/or neovascularization (Heiss C et al, 2005). In hypertension the number of circulating EPCs is reduced and their function is altered; this situation represents an additional risk factor in the development of cardiovascular events. It has been shown that Ang II and AngII-induced oxidative stress play a pivotal role in EPC status by accelerating the onset of their senescence, which, in turn, leads to impairment of their proliferative activity (Imanishi T et al, 2005). The calcitonin gene-related peptide (CGRP), instead, is a potent vasorelaxant, which prevents circulating EPC senescence and reverses AngII-induced senescence of EPC (Zhou Z et al, 2010). The important role that oxidative stress plays in the cardiovascular remodelling and atherogenetic processes, that are observed in hypertension, has led researchers to investigate the potential pleiotropic effects of antihypertensive drugs on oxidative stress. In particular, two drugs families are more intensive studied: ACE inhibitors (ACEIs) and the Ang II type 1 receptor blocker (ARBs) which both reduce RAAS activity. Olmesartan Medoxomil, widely used in the treatment of hypertension, blocks specifically AT1R receptor and consequently its actions via short and long term signaling independently of the Ang II source. AngII is, then, available for binding to AT2R inducing vasodilatation, anti-inflammatory and antifibrotic effects and causing a dose-dependent reduction of blood pressure. Furthemore, the treatment with Olmesartan has been shown to possess antioxidant-related effects such as reduction of the plasma levels 8-isoprostane, a marker of oxidative stress (Fliser D et al, 2005), and activation of Nitric Oxide (NO) system, through increase of eNOS phosphorylation (Oyama N et al, 2010; Kanematsu Y et al, 2006). The aim of our study was, therefore, to evaluate a possible anti-oxidant and vasoprotective effect of the Olmesartan Medoxomil, in essential hypertensive patients, using a molecular biology approach. The study was carried out at different times, using two cohorts of essential hypertensive patients with similar clinical features treated for six months with Olmesartan Medoxomil. On the first cohort of patients we analyzed markers of oxidative stress and cardiovascular remodelling-related pathways, as well as the level of oxidized LDL; on the second cohort of patients, we evaluated both the protein expression of HO-1, the plasma levels of CGRP and circulating EPCs number and senescence. In particular, in the first phase of the study, we evaluated p22phox, subunit of NADPH oxidase, essential for the production of superoxide anion (O2-), and heme oxygenase-1 (HO-1), inducible isoform of HO, known to protect from oxidative stress. We also evaluated the state of phosphorylation of extracellular signal-regulated kinases (ERK1/2), an oxidative stress protein effector for cardiovascular remodeling, and the plasma level of the low-density lipoproteins (OxLDL), a plasma marker of oxidative stress, which is crucial in the development of arteries chronic inflammation at intima level. In the second phase of the study, we evaluated the vasoprotective effects of Olmesartan, considering parameters such as: HO-1, potent anti-oxidant and anti-inflammatory protein, characterized by a strong effect on re-endothelialization, which is linked to its ability to increase the number and to reduce the senescence of circulating EPC; CGRP, peptide-stimulated by HO-1, that protect the endothelium and prevents circulating EPCs senescence. Moreover, were evaluated the number and survival of circulating EPCs. The results of the first phase of the study, have demonstrated that Olmesartan Midoxomil, besides inducing blood pressure normalization in essential hypertensive patients since the third month of treatment, significantly reduced p22phox protein level after 3 months compared to baseline (0.71±0.26 vs 0,93±0.24 densitometric unit (d.u.,), p<0.001), and moreover significantly reduced p22phox at 6 months both compared to baseline (0.45±0.12 vs 0.93±0.24 d.u., p<0.001) and to 3 months (0.45±0.12 vs 0.71±0.26 d.u., p<0.02). Olmesartan treatment also significantly decreased phosphorylated ERK 1/2 levels, both after 3 months compared to baseline (0.39±0.14 vs 0.56±0.11 d.u., p=0.001), and at 6 months compared to baseline (0.19±0.08 vs 0.56±0.11, d.u., p=0.001) and to 3 months (0.19±0.08 vs 0.39±0.14, d.u., p=0.001). oxLDL plasma levels were significantly reduced after 6 months of treatment, both compared to baseline (171.92±61,83 vs 300.84±109.13 ng/ml, p=0.001), and to 3 months (171.92±61,83 vs 270.06±100.34 ng/ml, p=0.002), whereas at 3 months the reduction was not significant. Furthermore, Olmesartan treatment caused a significant increase of HO-1 protein expression levels at 3 months of the therapy compared to baseline (1.10±0.19 vs 0.77±0.071 d.u., p=0.001) and at 6 months of the therapy compared to baseline (1.11±0.19 vs 0.77±0.071 d.u., p=0.001). There was no significant increase of HO-1 protein expression between 6 and 3 months of Olmesartan treatment (1.11±0.19 vs 1.10±0.19 d.u., p=ns). In the second phase of the study, confirming the previously shown increase of HO-1, we found that Olmesartan significantly increased HO-1 protein level, both at 3 months compared to baseline (0.95±0,21 vs 0.81±0.21 d.u., p=0.031), and at 6 months compared to baseline (1.1±0.26 vs 0.81±0.21 d.u., p=0.001) and to 3 months (1.1±0.26 vs 0.95±0.21 d.u., p=0.01). Moreover, we observed a significantly increase of CGRP plasma levels after 6 months of therapy, both compared to baseline (263.91±43.08 vs 198.81±51.98 pg/ml, p=0.001), and to 3 months (263.91±43.08 vs 218.97±41.13 pg/ml, p=0.03). Circulating EPC number, defined by cell surface antigens CD34+KDR+, CD133+KDR+ e CD34+CD133+KDR+, increased after 6 months of Olmesartan treatment both compared to baseline (respectively, 112.89±53.44 vs 35.11±25.98, p=0.005; 107.60±37.09 vs 20.90±14.58, p=0.0001; 38.11±19.64 vs 3.67±3.61, p=0.0007) and compared to 3 months (respectively, 112.89±53.44 vs 59.11±35.30, p=0.002; 107.60±37.09 vs 49.50±45.20, p=0.003; 38.11±19.64 vs 15.78±18.59, p=0.0028). Olmesartan significantly reduced EPC apoptosis, evaluated by gating on CD133+KDR+ cells events based on Annexin V expression, at 3 months compared to baseline (27.24± 9.64% vs 44.28 ± 12.38%, p<0.01) and further significantly reduced it at 6 months both compared to baseline (16.83±15.68% vs 44.28 ±12.38%, p<0.001) and to 3 months (16.83±15.68% vs 27.24±9.64%, p< 0.004) (Calò LA et al, 2014). In conclusion, this study demonstrates Olmesartan’s inhibitory effect on oxidative stress and oxidative stress-related proteins involved in oxidative stress signaling in essential hypertensive patients. Moreover, it demonstrates a vasoprotective effect of Olmesartan via reduction of Ang II-mediated oxidative stress and increased CGRP-mediated improvement of endothelial dysfunction, likely due also to the increased number of circulating EPC and their improved survival/function. In addition, our data provide a mechanistic rationale for the Olmesartan’s antioxidant and anti-inflammatory potential translation, in the long term, toward antiatherosclerotic and antiremodeling effects reported in clinical trials such as MORE (Stumpe KO et al 2007), OLIVUS (Hirohata A et al, 2010), EUTOPIA (Fliser D et al, 2004) e VIOS (Smith RD et al, 2006

A minimization approach to the wave equation on time-dependent domains

We prove the existence of weak solutions to the homogeneous wave equation on a suitable class of time-dependent domains. Using the approach suggested by De Giorgi and developed by Serra and Tilli, such solutions are approximated by minimizers of suitable functionals in space-time

A minimization approach to the wave equation on time-dependent domains

We prove the existence of weak solutions to the homogeneous wave equation on a suitable class of time-dependent domains. Using the approach suggested by De Giorgi and developed by Serra and Tilli, such solutions are approximated by minimizers of suitable functionals in space-time

Γ-Convergence of free discontinuity problems

We study the Γ-convergence of sequences of free-discontinuity functionals depending on vector-valued functions u which can be discontinuous across hypersurfaces whose shape and location are not known a priori. The main novelty of our result is that we work under very general assumptions on the integrands which, in particular, are not required to be periodic in the space variable. Further, we consider the case of surface integrands which are not bounded from below by the amplitude of the jump of u. We obtain three main results: compactness with respect to Γ-convergence, representation of the Γ-limit in an integral form and identification of its integrands, and homogenisation formulas without periodicity assumptions. In particular, the classical case of periodic homogenisation follows as a by-product of our analysis. Moreover, our result covers also the case of stochastic homogenisation, as we will show in a forthcoming paper

A global method for deterministic and stochastic homogenisation in BV

In this paper we study the deterministic and stochastic homogenisation of free-discontinuity functionals under linear growth and coercivity conditions. The main novelty of our deterministic result is that we work under very general assumptions on the integrands which, in particular, are not required to be periodic in the space variable. Combining this result with the pointwise Subadditive Ergodic Theorem by Akcoglu and Krengel, we prove a stochastic homogenisation result, in the case of stationary random integrands. In particular, we characterise the limit integrands in terms of asymptotic cell formulas, as in the classical case of periodic homogenisation

Self-similarity and long-time behavior of solutions of the diffusion equation with nonlinear absorption and a boundary source

This paper deals with the long-time behavior of solutions of nonlinear reaction-diffusion equations describing formation of morphogen gradients, the concentration fields of molecules acting as spatial regulators of cell differentiation in developing tissues. For the considered class of models, we establish existence of a new type of ultra-singular self-similar solutions. These solutions arise as limits of the solutions of the initial value problem with zero initial data and infinitely strong source at the boundary. We prove existence and uniqueness of such solutions in the suitable weighted energy spaces. Moreover, we prove that the obtained self-similar solutions are the long-time limits of the solutions of the initial value problem with zero initial data and a time-independent boundary source

Characteristics of people living in Italy after a cancer diagnosis in 2010 and projections to 2020

BACKGROUND: Estimates of cancer prevalence are widely based on limited duration, often including patients living after a cancer diagnosis made in the previous 5 years and less frequently on complete prevalence (i.e., including all patients regardless of the time elapsed since diagnosis). This study aims to provide estimates of complete cancer prevalence in Italy by sex, age, and time since diagnosis for all cancers combined, and for selected cancer types. Projections were made up to 2020, overall and by time since diagnosis. METHODS: Data were from 27 Italian population-based cancer registries, covering 32% of the Italian population, able to provide at least 7 years of registration as of December 2009 and follow-up of vital status as of December 2013. The data were used to compute the limited-duration prevalence, in order to estimate the complete prevalence by means of the COMPREV software. RESULTS: In 2010, 2,637,975 persons were estimated to live in Italy after a cancer diagnosis, 1.2 million men and 1.4 million women, or 4.6% of the Italian population. A quarter of male prevalent cases had prostate cancer (n\u2009=\u2009305,044), while 42% of prevalent women had breast cancer (n\u2009=\u2009604,841). More than 1.5 million people (2.7% of Italians) were alive since 5 or more years after diagnosis and 20% since 6515 years. It is projected that, in 2020 in Italy, there will be 3.6 million prevalent cancer cases (+\u200937% vs 2010). The largest 10-year increases are foreseen for prostate (+\u200985%) and for thyroid cancers (+\u200979%), and for long-term survivors diagnosed since 20 or more years (+\u200945%). Among the population aged 6575 years, 22% will have had a previous cancer diagnosis. CONCLUSIONS: The number of persons living after a cancer diagnosis is estimated to rise of approximately 3% per year in Italy. The availability of detailed estimates and projections of the complete prevalence are intended to help the implementation of guidelines aimed to enhance the long-term follow-up of cancer survivors and to contribute their rehabilitation need

Cure indicators and prevalence by stage at diagnosis for breast and colorectal cancer patients: A population‐based study in Italy

People alive many years after breast (BC) or colorectal cancer (CRC) diagnoses are increasing. This paper aimed to estimate the indicators of cancer cure and complete prevalence for Italian patients with BC and CRC by stage and age. A total of 31 Italian Cancer Registries (47% of the population) data until 2017 were included. Mixture cure models allowed estimation of net survival (NS); cure fraction (CF); time to cure (TTC, 5-year conditional NS &gt;95%); cure prevalence (who will not die of cancer); and already cured (prevalent patients living longer than TTC). 2.6% of all Italian women (806,410) were alive in 2018 after BC and 88% will not die of BC. For those diagnosed in 2010, CF was 73%, 99% when diagnosed at stage I, 81% at stage II, and 36% at stages III-IV. For all stages combined, TTC was &gt;10 years under 45 and over 65 years and for women with advanced stages, but &lt;= 1 year for all BC patients at stage I. The proportion of already cured prevalent BC women was 75% (94% at stage I). Prevalent CRC cases were 422,407 (0.7% of the Italian population), 90% will not die of CRC. For CRC patients, CF was 56%, 92% at stage I, 71% at stage II, and 35% at stages III-IV. TTC was &lt;= 10 years for all age groups and stages. Already cured were 59% of all prevalent CRC patients (93% at stage I). Cancer cure indicators by stage may contribute to appropriate follow-up in the years after diagnosis, thus avoiding patients' discrimination