The chronic fatigue syndrome: A comparative pathway analysis

In this paper, we introduce a method to detect pathological pathways of a disease. We aim to identify biological processes rather than single genes affected by the chronic fatigue syndrome (CFS). So far, CFS has neither diagnostic clinical signals nor abnormalities that could be diagnosed by laboratory examinations. It is also unclear if the CFS represents one disease or can be subdivided in different categories. We use information from clinical trials, the gene ontology (GO) database as well as gene expression data to identify undirected dependency graphs (UDGs) representing biological processes according to the GO database. The structural comparison of UDGs of sick versus non-sick patients allows us to make predictions about the modification of pathways due to pathogenesis.

Adrenomedullin Gene Delivery is Cardio-protective in a Model of Chronic Nitric Oxide Deficiency Combining Pressure Overload, Oxidative Stress and Cardiomyocyte Hypertrophy

BACKGROUND/AIMS:
Chronic inhibition of nitric oxide (NO) synthesis is associated with hypertension, myocardial ischemia, oxidative stress and hypertrophy; expression of the vasodilator peptide, adrenomedullin (AM) and its receptors is augmented in cardiomyocytes, indicating that the myocardial AM system may be activated in response to pressure loading and ischemic insult to serve a counter-regulatory, cardio-protective role. The study examined the hypothesis that oxidative stress and hypertrophic remodeling in NO-deficient cardiomyocytes are attenuated by adenoviral vector-mediated delivery of the human adrenomedullin (hAM) gene in vivo.

METHODS:
The NO synthesis inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME, 15mg . kg(-1) . day(-1)) was given to rats for 4 weeks following systemic administration via the tail vein of a single injection of either adenovirus harbouring hAM cDNA under the control of the cytomegalovirus promoter-enhancer (Ad.CMV-hAM-4F2), or for comparison, adenovirus alone (Ad.Null) or saline. Cardiomyocytes were subsequently isolated for assessment of the influence of each intervention on parameters of oxidative stress and hypertrophic remodelling.

RESULTS: Cardiomyocyte expression of the transgene persisted for > or =4 weeks following systemic administration of adenoviral vector. In L-NAME treated rats, relative to Ad.Null or saline administration, Ad.CMV-hAM-4F2 (i) reduced augmented cardiomyocyte membrane protein oxidation and mRNA expression of pro-oxidant (p22phox) and anti-oxidant (SOD-3, GPx) genes; (ii) attenuated increased cardiomyocyte width and mRNA expression of hypertrophic (sk-alpha-actin) and cardio-endocrine (ANP) genes; (iii) did not attenuate hypertension.

CONCLUSIONS: Adenoviral vector mediated delivery of hAM resulted in attenuation of myocardial oxidative stress and hypertrophic remodelling in the absence of blood pressure reduction in this model of chronic NO-deficiency. These findings are consistent with a direct cardio-protective action in the myocardium of locally-derived hAM which is not dependant on NO generation.

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.

ZapA, a virulence factor in a rat model of Proteus mirabilis-induced acute and chronic prostatitis.

Our knowledge of pathogenesis has benefited from a better understanding of the roles of specific virulence factors in disease. To determine the role of the virulence factor ZapA, a 54-kDa metalloproteinase of Proteus mirabilis, in prostatitis, rats were infected with either wild-type (WT) P. mirabilis or its isogenic ZapA- mutant KW360. The WT produced both acute and chronic prostatitis showing the typical histological progressions that are the hallmarks of these diseases. Infection with the ZapA- mutant, however, resulted in reduced levels of acute prostatitis, as determined from lower levels of tissue damage, bacterial colonization, and inflammation. Further, the ZapA- mutant failed to establish a chronic infection, in that bacteria were cleared from the prostate, inflammation was resolved, and tissue was seen to be healing. Clearance from the prostate was not the result of a reduced capacity of the ZapA- mutant to form biofilms in vitro. These finding clearly define ZapA as an important virulence factor in both acute and chronic bacterial prostatitis.

Development of a novel DNA microarray to detect bacterial pathogens in patients with chronic obstructive pulmonary disease (COPD)

A novel microarray was constructed with DNA PCR product probes targeting species specific functional genes of nine clinically significant respiratory pathogens, including the Gram-positive organisms (Streptococcus pneumoniae, Streptococcus pyogenes), the Gram-negative organisms (Chlamydia pneumoniae, Coxiella burnetii Haemophilus spp., Legionella pneumophila, Moraxella catarrhalis, and Pseudomonas aeruginosa), as well as the atypical bacterium, Mycoplasma pneumoniae. In a "proof-of-concept" evaluation of the developed microarray, the microarray was compared with real-time PCR from 14 sputum specimens from COPD patients. All of the samples positive for bacterial species in real-time PCR were also positive for the same bacterial species using the microarray. This study shows that a microarray using PCR probes is a potentially useful method to monitor the populations of bacteria in respiratory specimens and can be tailored to specific clinical needs such as respiratory infections of particular patient populations, including patients with cystic fibrosis and bronchiectasis. (C) 2010 Elsevier B.V. All rights reserved.