Zebrafish Model for Functional Screening of Flow-Responsive Genes.

OBJECTIVE: Atherosclerosis is initiated at branches and bends of arteries exposed to disturbed blood flow that generates low shear stress. This mechanical environment promotes lesions by inducing endothelial cell (EC) apoptosis and dysfunction via mechanisms that are incompletely understood. Although transcriptome-based studies have identified multiple shear-responsive genes, most of them have an unknown function. To address this, we investigated whether zebrafish embryos can be used for functional screening of mechanosensitive genes that regulate EC apoptosis in mammalian arteries. APPROACH AND RESULTS: First, we demonstrated that flow regulates EC apoptosis in developing zebrafish vasculature. Specifically, suppression of blood flow in zebrafish embryos (by targeting cardiac troponin) enhanced that rate of EC apoptosis (≈10%) compared with controls exposed to flow (≈1%). A panel of candidate regulators of apoptosis were identified by transcriptome profiling of ECs from high and low shear stress regions of the porcine aorta. Genes that displayed the greatest differential expression and possessed 1 to 2 zebrafish orthologues were screened for the regulation of apoptosis in zebrafish vasculature exposed to flow or no-flow conditions using a knockdown approach. A phenotypic change was observed in 4 genes; p53-related protein (PERP) and programmed cell death 2-like protein functioned as positive regulators of apoptosis, whereas angiopoietin-like 4 and cadherin 13 were negative regulators. The regulation of perp, cdh13, angptl4, and pdcd2l by shear stress and the effects of perp and cdh13 on EC apoptosis were confirmed by studies of cultured EC exposed to flow. CONCLUSIONS: We conclude that a zebrafish model of flow manipulation coupled to gene knockdown can be used for functional screening of mechanosensitive genes in vascular ECs, thus providing potential therapeutic targets to prevent or treat endothelial injury at atheroprone sites.

Disturbed flow promotes endothelial senescence via a p53-dependent pathway.

OBJECTIVE: Although atherosclerosis is associated with systemic risk factors such as age, high cholesterol, and obesity, plaque formation occurs predominately at branches and bends that are exposed to disturbed patterns of blood flow. The molecular mechanisms that link disturbed flow-generated mechanical forces with arterial injury are uncertain. To illuminate them, we investigated the effects of flow on endothelial cell (EC) senescence. APPROACH AND RESULTS: LDLR(-/-) (low-density lipoprotein receptor(-/-)) mice were exposed to a high-fat diet for 2 to 12 weeks (or to a normal chow diet as a control) before the assessment of cellular senescence in aortic ECs. En face staining revealed that senescence-associated ß-galactosidase activity and p53 expression were elevated in ECs at sites of disturbed flow in response to a high-fat diet. By contrast, ECs exposed to undisturbed flow did not express senescence-associated ß-galactosidase or p53. Studies of aortae from healthy pigs (aged 6 months) also revealed enhanced senescence-associated ß-galactosidase staining at sites of disturbed flow. These data suggest that senescent ECs accumulate at disturbed flow sites during atherogenesis. We used in vitro flow systems to examine whether a causal relationship exists between flow and EC senescence. Exposure of cultured ECs to flow (using either an orbital shaker or a syringe-pump flow bioreactor) revealed that disturbed flow promoted EC senescence compared with static conditions, whereas undisturbed flow reduced senescence. Gene silencing studies demonstrated that disturbed flow induced EC senescence via a p53-p21 signaling pathway. Disturbed flow-induced senescent ECs exhibited reduced migration compared with nonsenescent ECs in a scratch wound closure assay, and thus may be defective for arterial repair. However, pharmacological activation of sirtuin 1 (using resveratrol or SRT1720) protected ECs from disturbed flow-induced senescence. CONCLUSIONS: Disturbed flow promotes endothelial senescence via a p53-p21-dependent pathway which can be inhibited by activation of sirtuin 1. These observations support the principle that pharmacological activation of sirtuin 1 may promote cardiovascular health by suppressing EC senescence at atheroprone sites.

"If I'm at home, I do it at home": Qualitative study on HIV self-testing among transgender women in Argentina.

BACKGROUND: Evidence among key populations supports acceptability of HIV self-testing (HIVST) due to its privacy and convenience. However, insufficient research has been done among transgender women (TGW), especially in Latin America. Consequently, the aim of this study was to explore the acceptability, perceptions and recommendations for HIVST implementation among TGW in Buenos Aires. METHODS: A focus group was conducted in July 2019. Particpants were invited to touch and learn about a displayed HIVST kit. The following main topics were explored: acceptability, reasons for seeking self-testing, preferences for training, distribution, periodicity and recommendations for HIVST implementation. RESULTS: The sample consisted of 12 TGWs; mean age of 26 years (IQR = 22-28); 66% had history of sex-work. The main motivations for seeking HIVST were convenience, privacy, and usage to reduce stigma and discrimination by health-care providers. Recommendations for HIVST were: distribution from primary health centers and trans-sensitive centers; affordable price; assistance by peer health promoters; and the provision of clear written and video instructions. CONCLUSIONS: Tailored implementation of HIVST can increase HIV testing rates, early detection, and linkage to HIV-care in this high-prevalence group. This study provided community-driven suggestions to inform and adapt an HIVST feasibility pilot study and future implementation in Argentina.

The two behavioural risk factor surveillances on the adult and elderly populations as information systems for leveraging data on health-related sustainable development goals in Italy.

INTRODUCTION: Current lengthening of average life and constant increase of population ageing associated to forces that include rapid unplanned urbanisation and globalisation of unhealthy behaviours have determined the huge relevance of noncommunicable diseases (NCDs). Monitoring key modifiable behavioural risk factors has resulted to be crucial both in spatial terms and as per temporal trends in order to allow comparisons between different geographic areas or levels and over time. MATERIALS AND METHODS: In Italy, PASSI (Progressi delle Aziende Sanitarie per la Salute in Italia) and Passi d'Argento are the ongoing Behavioural Risk Factor Surveillance Systems (BRFSSs), respectively, on adults (people aged 18-69) and elderly (65 and older). RESULTS: The two Italian surveillances are information systems providing data not only on the third Sustainable Development Goal (SDG) that explicitly addresses ensuring healthy lives and promoting well-being for all, but on a total of nine health-related SDGs (HRSDGs) and 19 HRSDG targets/indicators. We describe these pairs more in detail specifying where in case of BRFSS core indicators (N = 14 HRSDG targets/indicators) concerning six HRSDGs or, on the other hand, as per BRFSS further in-depth analysis (N = five HRSDG targets/indicators) in regard of four different HRSDGs. About the HRSDG 3, HRSDG target 3.4, HRSDG indicator 3.4.1, from the PASSI and Passi d'Argento data it is possible not only to detect the prevalence of NCDs in adults and elderly living in Italy, but also to evaluate the social determinants of health, such as gender, age group, educational level, economic difficulties, as well as the associations with modifiable lifestyle risk factors. CONCLUSIONS: The two Italian BRFSSs generate accurate data, which are highly relevant to design, implement, monitor, and evaluate programs and policies at different levels (local, regional, national) for NCD prevention and health promotion. They provide numbers which can also serve as propaedeutic or, in some cases, complementary ground to address a robust measurement of several HRSDG patterns.

Elevated uptake of plasma macromolecules by regions of arterial wall predisposed to plaque instability in a mouse model.

Atherosclerosis may be triggered by an elevated net transport of lipid-carrying macromolecules from plasma into the arterial wall. We hypothesised that whether lesions are of the thin-cap fibroatheroma (TCFA) type or are less fatty and more fibrous depends on the degree of elevation of transport, with greater uptake leading to the former. We further hypothesised that the degree of elevation can depend on haemodynamic wall shear stress characteristics and nitric oxide synthesis. Placing a tapered cuff around the carotid artery of apolipoprotein E -/- mice modifies patterns of shear stress and eNOS expression, and triggers lesion development at the upstream and downstream cuff margins; upstream but not downstream lesions resemble the TCFA. We measured wall uptake of a macromolecular tracer in the carotid artery of C57bl/6 mice after cuff placement. Uptake was elevated in the regions that develop lesions in hyperlipidaemic mice and was significantly more elevated where plaques of the TCFA type develop. Computational simulations and effects of reversing the cuff orientation indicated a role for solid as well as fluid mechanical stresses. Inhibiting NO synthesis abolished the difference in uptake between the upstream and downstream sites. The data support the hypothesis that excessively elevated wall uptake of plasma macromolecules initiates the development of the TCFA, suggest that such uptake can result from solid and fluid mechanical stresses, and are consistent with a role for NO synthesis. Modification of wall transport properties might form the basis of novel methods for reducing plaque rupture.

Sulforaphane pretreatment prevents systemic inflammation and renal injury in response to cardiopulmonary bypass.

OBJECTIVES: Systemic inflammatory responses are a major cause of morbidity and mortality in patients undergoing cardiac surgery with cardiopulmonary bypass. However, the underlying molecular mechanisms for systemic inflammation in response to cardiopulmonary bypass are poorly understood. METHODS: A porcine model was established to study the signaling pathways that promote systemic inflammation in response to cardiac surgery with cardiopulmonary bypass under well-controlled experimental conditions. The influence of sulforaphane, an anti-inflammatory compound derived from green vegetables, on inflammation and injury in response to cardiopulmonary bypass was also studied. Intracellular staining and flow cytometry were performed to measure phosphorylation of p38 mitogen-activated protein kinase and the transcription factor nuclear factor-κB in granulocytes and mononuclear cells. RESULTS: Surgery with cardiopulmonary bypass for 1 to 2 hours enhanced phosphorylation of p38 (2.5-fold) and nuclear factor-κB (1.6-fold) in circulating mononuclear cells. Cardiopulmonary bypass also modified granulocytes by activating nuclear factor-κB (1.6-fold), whereas p38 was not altered. Histologic analyses revealed that cardiopulmonary bypass promoted acute tubular necrosis. Pretreatment of animals with sulforaphane reduced p38 (90% reduction) and nuclear factor-κB (50% reduction) phosphorylation in leukocytes and protected kidneys from injury. CONCLUSIONS: Systemic inflammatory responses after cardiopulmonary bypass were associated with activation of p38 and nuclear factor-κB pathways in circulating leukocytes. Inflammatory responses to cardiopulmonary bypass can be reduced by sulforaphane, which reduced leukocyte activation and protected against renal injury.

The role of blood flow in determining the sites of atherosclerotic plaques.

Atherosclerosis is a chronic inflammatory disease characterized by the accumulation of lipids and inflammatory cells along the inner walls of arteries, and is an underlying cause of cardiovascular disease. Atherosclerotic lesions develop predominantly at branches, bends, and bifurcations in the arterial tree because these sites are exposed to low or disturbed blood flow, which exerts low/oscillatory shear stress on the vessel wall. This mechanical environment alters endothelial cell physiology by enhancing inflammatory activation. In contrast, regions of the arterial tree that are exposed to uniform, unidirectional blood flow and experience high shear stress are protected from inflammation and lesion development. Shear stress is sensed by the endothelium via mechanoreceptors and is subsequently transduced into biochemical signals resulting in modulation of proinflammatory signaling pathways. In this article, we address the molecular mechanisms behind the spatial localization of vascular inflammation and atherosclerosis, with particular focus on studies by our own group of two key proinflammatory signaling pathways, the mitogen-activated protein kinase pathway and the nuclear factor-kappa-B pathway.

Cyclophosphamide pulse regimen in the treatment of alveolitis in systemic sclerosis.

OBJECTIVE: To evaluate, in a pilot study, the efficacy of a short term cyclophosphamide (CYC) pulse regimen on alveolitis in a cohort of patients with systemic sclerosis (SSc). METHODS: Twenty-three patients with SSc (17 diffuse SSc and 6 limited SSc) were selected in 5 centers in Italy, based on the findings of an abnormal bronchoalveolar lavage (BAL) cell analysis in association with altered pulmonary function tests (PFT) or recent deterioration in flow volume curve (FVC). Patients were also evaluated by skin score (Rodnan), esophageal manometry and barium swallow radiography, and electrocardiography and 2-mode echocardiography. The pre-enrolment pulmonary evaluation and after 6 months of therapy included evaluation of the clinical status, PFT (FVC, FEV1, DLCO), BAL. standard chest radiograph, and chest high resolution computed tomography. All patients received i.v. CYC (1000 mg/m2 of body surface monthly for 6 mo) and oral prednisone (25 mg daily for the first month and subsequently 5 mg daily of maintenance dosage for the remaining 5 mo). A complete blood count and urinalysis were obtained at monthly intervals. RESULTS: After 6 months of therapy the values for FVC did not change significantly. Individually, 8 of 23 patients showed an improvement (> 15% increase) in FVC after 6 months, while FVC in 13 cases remained stable. Only 2 patients had an important decline in FVC after 6 months of therapy (17 and 24% decrease). Improvement in DLCO was noted in 15 of 23 patients after 6 months of therapy. Four patients were stable and 4 patients had a worsened DLCO at the end of the study. After therapy the mean value of BAL fluid recovery did not change. There was a reduction in total cell number although this value did not reach statistical significance. The levels of neutrophils, eosinophils, lymphocytes, and macrophages did not change significantly. Scans for patients with grades 1, 2, and 3 did not differ significantly after 6 months of therapy, and 14 patients were stable. Changes in appearance, in relation to changes in extent of disease, were seen in 8 patients and consisted of an extension of reticular pattern and transformation from grade 1 to 2 (6/8 patients). All patients showed a ground-glass appearance indicating an acute alveolitis. Improvement in ground-glass was noted in 10 of 23 patients after 6 mo therapy. At the end of the study, 8 patients were stable and 5 patients had a diffusion of the ground-glass to other segments. No side effects were experienced during the treatment except for mild nausea in 4 patients; no patients discontinued therapy during the study. CONCLUSION: CYC pulse regimen seems to stabilize alveolitis in the majority of cases. The association of CYC pulsed modality with prednisone may be useful in SSc patients to control disease evolution in the lung.