Endothelial-specific Nox2 overexpression increases vascular superoxide and macrophage recruitment in ApoE−/− mice

AIMS: Vascular disease states are associated with endothelial dysfunction and increased production of reactive oxygen species derived from NADPH oxidases. However, it remains unclear whether a primary increase in superoxide production specifically in the endothelium alters the initiation or progression of atherosclerosis. METHODS AND RESULTS: Mice overexpressing Nox2 specifically in the endothelium (Nox2-Tg) were crossed with ApoE(-/-) mice to produce Nox2-Tg ApoE(-/-) mice and ApoE(-/-) littermates. Endothelial overexpression of Nox2 in ApoE(-/-) mice did not alter blood pressure, but significantly increased vascular superoxide production compared with ApoE(-/-) littermates, measured using both lucigenin chemiluminescence and 2-hydroxyethidium production (ApoE(-/-), 19.9 ± 6.3 vs. Nox2-Tg ApoE(-/-), 47.0 ± 7.0 nmol 2-hydroxyethidium/aorta, P< 0.05). Increased endothelial superoxide production increased endothelial levels of vascular cell adhesion protein 1 and enhanced macrophage recruitment in early lesions in the aortic roots of 9-week-old mice, indicating increased atherosclerotic plaque initiation. However, endothelial-specific Nox2 overexpression did not alter native or angiotensin II-driven atherosclerosis in either the aortic root or the descending aorta. CONCLUSION: Endothelial-targeted Nox2 overexpression in ApoE(-/-) mice is sufficient to increase vascular superoxide production and increase macrophage recruitment possible via activation of endothelial cells. However, this initial increase in macrophage recruitment did not alter the progression of atherosclerosis. These results indicate that Nox-mediated reactive oxygen species signalling has important cell-specific and distinct temporal roles in the initiation and progression of atherosclerosis

Increased myocardial NADPH oxidase activity in human heart failure

AbstractObjectivesThis study was designed to investigate whether nicotinamide adenine dinucleotide 3-phosphate (reduced form) (NADPH) oxidase is expressed in the human heart and whether it contributes to reactive oxygen species (ROS) production in heart failure.BackgroundA phagocyte-type NADPH oxidase complex is a major source of ROS in the vasculature and is implicated in the pathophysiology of hypertension and atherosclerosis. An increase in myocardial oxidative stress due to excessive production of ROS may be involved in the pathophysiology of congestive heart failure. Recent studies have suggested an important role for myocardial NADPH oxidase in experimental models of cardiac disease. However, it is unknown whether NADPH oxidase is expressed in the human myocardium or if it has any role in human heart failure.MethodsMyocardium of explanted nonfailing (n = 9) and end-stage failing (n = 13) hearts was studied for the expression of NADPH oxidase subunits and oxidase activity.ResultsThe NADPH oxidase subunits p22phox, gp91phox, p67phox, and p47phoxwere all expressed at messenger ribonucleic acid and protein level in cardiomyocytes of both nonfailing and failing hearts. NADPH oxidase activity was significantly increased in end-stage failing versus nonfailing myocardium (5.86 ± 0.41 vs. 3.72 ± 0.39 arbitrary units; p < 0.01). The overall level of oxidase subunit expression was unaltered in failing compared with nonfailing hearts. However, there was increased translocation of the regulatory subunit, p47phox, to myocyte membranes in failing myocardium.ConclusionsThis is the first report of the presence of NADPH oxidase in human myocardium. The increase in NADPH oxidase activity in the failing heart may be important in the pathophysiology of cardiac dysfunction by contributing to increased oxidative stress

Endothelial cell-specific ROS production increases susceptibility to aortic dissection

Background—Increased production of reactive oxygen species (ROS) throughout the vascular wall is a feature of cardiovascular disease states, but therapeutic strategies remain limited by our incomplete understanding of the role and contribution of specific vascular cell ROS to disease pathogenesis. To investigate the specific role of endothelial cell (EC) ROS in the development of structural vascular disease, we generated a mouse model of endothelium-specific Nox2 overexpression and tested the susceptibility to aortic dissection after angiotensin II (Ang II) infusion. Methods and Results—A specific increase in endothelial ROS production in Nox2 transgenic mice was sufficient to cause Ang II–mediated aortic dissection, which was never observed in wild-type mice. Nox2 transgenic aortas had increased endothelial ROS production, endothelial vascular cell adhesion molecule-1 expression, matrix metalloproteinase activity, and CD45+ inflammatory cell infiltration. Conditioned media from Nox2 transgenic ECs induced greater Erk1/2 phosphorylation in vascular smooth muscle cells compared with wild-type controls through secreted cyclophilin A (CypA). Nox2 transgenic ECs (but not vascular smooth muscle cells) and aortas had greater secretion of CypA both at baseline and in response to Ang II stimulation. Knockdown of CypA in ECs abolished the increase in vascular smooth muscle cell Erk1/2 phosphorylation conferred by EC conditioned media, and preincubation with CypA augmented Ang II–induced vascular smooth muscle cell ROS production. Conclusions—These findings demonstrate a pivotal role for EC-derived ROS in the determination of the susceptibility of the aortic wall to Ang II–mediated aortic dissection. ROS-dependent CypA secretion by ECs is an important signaling mechanism through which EC ROS regulate susceptibility of structural components of the aortic wall to aortic dissection

A pilot trial of moderated online social therapy for family and friends of young people with borderline personality disorder features

Aim We evaluated the acceptability, usability and safety of Kindred, a novel online intervention for carers of young people with borderline personality disorder (BPD) using a pre–post pilot trial design. The secondary aim explored whether Kindred use was associated with clinical improvements for caregivers on measures of burden of caregiving, stress, expressed emotion, family communication, disability, coping and knowledge of BPD and for patients on measures of severity of BPD symptoms and level of functional impairment. Methods The trial site was the Helping Young People Early program for young people with BPD at Orygen in Melbourne, Australia. Informed consent was obtained from 20 adult carers (i.e., relatives or friends) and 10 young people aged 15–25 with BPD. Kindred, which was available for 3 months, incorporated online psychoeducation, carer-to-carer social networking and guidance from expert and peer moderators. Assessments were completed at baseline and 3 months follow-up. Multiple indicators of acceptability, usability and safety were utilized. Results Seventeen carers were enrolled in Kindred and eight young people completed baseline measures. A priori acceptability, usability and safety criteria were met. Carer burden, stress, expressed emotion, family communication, quality of life, functioning, coping and perceived knowledge of BPD improved at follow-up. Sixty-six percent of the young people (4/6) reported that they believed Kindred had improved their carers' understanding of BPD. Conclusion Kindred was shown to be acceptable, usable and safe, with encouraging improvements in both carer and young person outcomes. Kindred warrants evaluation of its efficacy via an randomized controlled trial

A comparison of experiences of care and expressed emotion among caregivers of young people with first-episode psychosis or borderline personality disorder features

Objective: Caregivers of individuals with severe mental illness often experience significant negative experiences of care, which can be associated with higher levels of expressed emotion. Expressed emotion is potentially a modifiable target early in the course of illness, which might improve outcomes for caregivers and patients. However, expressed emotion and caregiver experiences in the early stages of disorders might be moderated by the type of severe mental illness. The aim was to determine whether experiences of the caregiver role and expressed emotion differ in caregivers of young people with first-episode psychosis versus young people with ‘first-presentation’ borderline personality disorder features. Method: Secondary analysis of baseline (pre-treatment) data from three clinical trials focused on improving caregiver outcomes for young people with first-episode psychosis and young people with borderline personality disorder features was conducted (ACTRN12616000968471, ACTRN12616000304437, ACTRN12618000616279). Caregivers completed self-report measures of experiences of the caregiver role and expressed emotion. Multivariate generalised linear models and moderation analyses were used to determine group differences. Results: Data were available for 265 caregivers. Higher levels of negative experiences and expressed emotion, and stronger correlations between negative experiences and expressed emotion domains, were found in caregivers of young people with borderline personality disorder than first-episode psychosis. Caregiver group (borderline personality disorder, first-episode psychosis) moderated the relationship between expressed emotion and caregiver experiences in the domains of need to provide backup and positive personal experiences. Conclusion: Caregivers of young people with borderline personality disorder experience higher levels of negative experiences related to their role and expressed emotion compared with caregivers of young people with first-episode psychosis. The mechanisms underpinning associations between caregiver experiences and expressed emotion differ between these two caregiver groups, indicating that different supports are needed. For borderline personality disorder caregivers, emotional over-involvement is associated with both negative and positive experiences, so a more detailed understanding of the nature of emotional over-involvement for each relationship is required to guide action