Genetically increased risk of sleep disruption in alzheimer's disease

STUDY OBJECTIVES: To investigate the role of a monoamine A oxidase promoter polymorphism in sleep disruption in Alzheimer's disease (AD). DESIGN: A case-control association analysis. SETTING: Sleep disturbance in AD is common, is extremely stressful for caregivers, and increases the risk of institutionalisation. It remains unclear why only some patients develop sleep disturbance; neuropathologic changes of AD are not typically seen in the areas of the brain responsible for sleep. We hypothesized that the risk of sleep disturbance is, at least in part, influenced by the availability of serotonin used for melatonin synthesis secondary to polymorphic variation at the enzyme monoamine oxidase A (MAO-A). PATIENTS: Patients with AD diagnosed according to standard criteria. INTERVENTIONS: Data were collected using the Sleep domain of the Neuropsychiatric Inventory with Caregiver Distress. Patients' cognition and function were assessed using the Mini-Mental State Examination and the Functional Assessment Staging. Genotyping of apolipoprotein E (APOE) and of the 30 bp variable number tandem repeat of the MAO-A promoter was by standard methods. MEASUREMENTS AND RESULTS: Of 426 patients surveyed, 54% experienced sleep disturbance. We found that the high-activity 4-repeat allele of the MAO-A VNTR promoter polymorphism confers increased susceptibility to sleep disturbance (p = .008). A quantitative sleep disturbance score was significantly higher in the patients possessing MAO-A 4-repeat allele genotypes. APOE had no influence on the development of an altered sleep phenotype. CONCLUSIONS: We conclude that sleep disturbance in AD is common and distressing and is associated with genetic variation at MAO-A.

Polymorphisms in SLC6A4, PAH, GABRB3, and MAOB and modification of psychotic disorder features

We tested four genes [phenylalanine hydroxylase (PAH), the serotonin transporter (SLC6A4), monoamine oxidase B (MAOB), and the gamma-aminobutyric acid A receptor beta-3 subunit (GABRB3)] for their impact on five schizophrenia symptom factors: delusions, hallucinations, mania, depression, and negative symptoms. In a 90 family subset of the Irish Study of High Density Schizophrenia Families, the PAH 232 bp microsatellite allele demonstrated significant association with the delusions factor using both QTDT (F = 8.0, p = .031) and QPDTPHASE (chi-square = 12.54, p = .028). Also, a significant association between the GABRB3 191 bp allele and the hallucinations factor was detected using QPDTPHASE (chi-square 15.51, p = .030), but not QTDT (chi-square = 2.07, p = .560). (C) 2009 Elsevier B.V. All rights reserved.

Involvement of Nox2 NADPH oxidase in adverse cardiac remodeling after myocardial infarction.

Oxidative stress plays an important role in the development of cardiac remodeling after myocardial infarction (MI), but the sources of oxidative stress remain unclear. We investigated the role of Nox2-containing reduced nicotinamide-adenine dinucleotide phosphate oxidase in the development of cardiac remodeling after MI. Adult Nox2(-/-) and matched wild-type (WT) mice were subjected to coronary artery ligation and studied 4 weeks later. Infarct size after MI was similar in Nox2(-/-) and WT mice. Nox2(-/-) mice exhibited significantly less left ventricular (LV) cavity dilatation and dysfunction after MI than WT mice (eg, echocardiographic LV end-diastolic volume: 75.7+/-5.8 versus 112.4+/-12.3 microL; ejection fraction: 41.6+/-3.7 versus 32.9+/-3.2%; both P

NADPH oxidase-4 mediates protection against chronic load-induced stress in mouse hearts by enhancing angiogenesis

Cardiac failure occurs when the heart fails to adapt to chronic stresses. Reactive oxygen species (ROS)-dependent signaling is implicated in cardiac stress responses but the role of different ROS sources remains unclear. Here, we report that NADPH oxidase-4 (Nox4) facilitates cardiac adaptation to chronic stress. Unlike other Nox proteins, Nox4 activity is regulated mainly by its expression level which increased in cardiomyocytes during stresses such as pressure overload or hypoxia. To investigate the functional role of Nox4 during the cardiac response to stress, we generated mice with a genetic deletion of Nox4 or a cardiomyocyte-targeted overexpression of Nox4. Basal cardiac function was normal in both models but Nox4-null animals developed exaggerated contractile dysfunction, hypertrophy and cardiac dilatation during exposure to chronic overload whereas Nox4-transgenic mice were protected. Investigation of mechanisms underlying this protective effect revealed a significant Nox4-dependent preservation of myocardial capillary density after pressure overload. Nox4 enhanced stress-induced activation of cardiomyocyte Hif1 and the release of VEGF, resulting in an increased paracrine angiogenic activity. These data indicate that cardiomyocyte Nox4 is a novel inducible regulator of myocardial angiogenesis, a key determinant of cardiac adaptation to overload stress. Our results also have wider relevance to the use of non-specific antioxidant approaches in cardiac disease and may provide an explanation for the failure of such strategies in many settings.