Increased activation of NADPH oxidase 4 in the pulmonary vasculature in experimental diaphragmatic hernia

Aim

Persistent pulmonary hypertension remains a major cause of mortality and morbidity in congenital diaphragmatic hernia (CDH). NADPH oxidases (Nox) are the main source of superoxide production in vasculature. Nox4 is highly expressed in the smooth muscle and endothelial cells of the vascular wall and increased activity has been reported in the pulmonary vasculature of both experimental and human pulmonary hypertension. Peroxisome proliferator-activated receptor (PPARγ) is a key regulator of Nox4 expression. Targeted depletion of PPARγ results in pulmonary hypertension phenotype whereas activation of PPARγ attenuates pulmonary hypertension and reduces Nox4 production. The nitrofen-induced CDH model is an established model to study the pathogenesis of pulmonary hypertension in CDH. It has been previously reported that PPARγ-signaling is disrupted during late gestation and H₂O₂ production is increased in nitrofen-induced CDH. We designed this study to investigate the hypothesis that Nox4 expression and activation is increased and vascular PPARγ is decreased in nitrofen-induced CDH.

Methods

Pregnant rats were treated with either nitrofen or vehicle on gestational day 9 (D9). Fetuses were sacrificed on D21 and divided into control and CDH. RT-PCR, western blotting and confocal-immunofluorescence-double-staining were performed to determine pulmonary expression levels of PPARγ, Nox4 and Nox4-activation (p22^phox).

Results

There was a marked increase in medial and adventitial thickness in pulmonary arteries of all sizes in CDH compared to controls. Pulmonary Nox4 levels were significantly increased whereas PPARγ levels were decreased in nitrofen-induced CDH compared to controls. Western blotting revealed increased pulmonary protein expression of the Nox4-activating subunit p22^phox and decreased protein expression of PPARγ in CDH compared to controls. Confocal-microscopy confirmed markedly increased pulmonary expression of the Nox4 activating subunit p22^phox accompanied by decreased perivascular PPARγ expression in lungs of nitrofen-exposed fetuses compared to controls.

Conclusion

To our knowledge, the present study is the first to report increased Nox4 production in the pulmonary vasculature of nitrofen-induced CDH. Down-regulation of the PPARγ-signaling pathway may lead to increased superoxide production, resulting in pulmonary vascular dysfunction and contributing to pulmonary hypertension in the nitrofen-induced CDH model. PPARγ-activation inhibiting Nox4 production may therefore represent a potential therapeutic approach for the treatment of pulmonary hypertension in CDH.     

Tissue-type plasminogen activator -7,351C/T enhancer polymorphism is associated with a first myocardial infarction

We recently identified a polymorphic Sp1 binding site in an enhancer at the tissue-type plasminogen activator (tPA) locus (tPA -7,351C/T), which was associated with vascular tPA release. Subjects homozygous for the -7,351C allele had twice the tPA release rate compared to subjects carrying the -7,351T allele. In this study we tested the hypothesis that the tPA -7,351C/T polymorphism is associated with myocardial infarction (MI). In a population-based prospective nested case-control study within northern Sweden, genotypes were determined among 61 MI cases and 120 controls. In a multivariate model, the tPA -7,351C/T polymorphism (OR 2.68 for T allele carriers; 95% CI 1.31-5.50), tPA antigen (OR 1.16; 95% CI 1.07-1.25) and apo A-I (OR, 0.997; 95% CI 0.995-0.999) were independently associated with a first MI. These findings suggest that genetic markers of local tPA release and circulating steady-state tPA levels carry independent prognostic information.     

Improved fibrinolysis after one year of treatment with enalapril in men and women with uncomplicated myocardial infarction

AIMS: To study long-term effects of enalapril on mass concentrations of tissue plasminogen activator (tPA), plasminogen activator inhibitor (PAI-1), tPA/PAI-1-complex and von Willebrand factor (vWF) in both genders with uncomplicated myocardial infarction. METHODS AND RESULTS: More than three months after an uncomplicated myocardial infarction 82 survivors (46 males, 36 females) were randomised to enalapril/placebo. PAI-1, tPA, tPA/PAI-1-complex and vWF were measured after two weeks, six and 12 months following randomisation. PAI-1 decreased significantly in both genders in the enalapril-treated group after two weeks, with a maximum decrease at six months (mean reduction: 31% equal to 9.8 microg x L(-1), CI: 5.2 to 14.5 microg x L(-1), p = 0.0001) and remained significantly lower at 12 months. Mass concentration of tPA decreased significantly (mean reduction: 1.81 microg x L(-1), CI: 0.903 to 2.708 microg x L(-1), p < 0.001) after two weeks treatment in both genders but returned to baseline values at 12 months. The tPA/PAI-1-complex decreased and was significantly lower (mean reduction 0.96 microg x L(-1), CI: 0.36 to 1.56 microg x L(-1), p = 0.003) in the enalapril group after two weeks and six months (p = 0.037). No decrease of vWF was seen in the enalapril group. CONCLUSIONS: Enalapril treatment up to one year depressed mass concentrations of PAI-1 and transiently tPA and tPA/PAI-1 complex indicating an improvement of the fibrinolytic balance in both genders with uncomplicated myocardial infarction.     

Dairy Products and Cancer Risk in a Northern Sweden Population

Abstract

The role of dairy products in cancer is unclear. We assessed consumption of fermented milk, non-fermented milk, cheese, and butter, estimated from semi-quantitative food frequency questionnaires, in relation to prospective risk of breast, prostate, colorectal, smoking-, and obesity-related cancers in 101,235 subjects, including 12,552 cancer cases, in the population-based Northern Sweden Health and Disease Study. Most analyses (n?=?20) rendered null results. In men, we observed an increased prostate cancer risk among high-consumers of cheese (hazard ratio (HR) for highest vs. lowest quintile (Q5–Q1), 1.11; 95% CI, 0.97–1.27; P^trend?=?0.013). In women, high-consumers of cheese had a decreased risk of overall cancer (HR Q5–Q1, 0.95; 95% CI, 0.88–1.04; P^trend?=?0.039), smoking-related (HR Q5–Q1, 0.84; 95% CI, 0.72–0.97; P^trend ≤ 0.001), and colorectal cancers (HR Q5–Q1, 0.82; 95% CI, 0.63–1.07; P^trend?=?0.048). Butter yielded a weak decreased obesity-related cancer risk in women (HR Q5–Q1, 0.91; 95% CI, 0.81–1.02; P^trend?=?0.049). Fermented milk yielded HRs below zero in women, but with no clear linear associations. In conclusion, this study does not support any major adverse or beneficial effects of fermented milk, non-fermented milk, cheese, and butter in the diet from a cancer risk perspective.     

Comparison of somatic development and status of conduit after extracardiac Fontan operation in young and older children

Objective: We set out to examine whether the extracardiac Fontan operation (ECFO) in young children is beneficial for the early postoperative course and whether it has a negative impact on the mid-term hemodynamics and growth of the children due to absent growth potential of the prosthetic conduit. Therefore we compared our medium-term experience with ECFO in children under 4 years of age to that in older children regarding the incidence of postoperative complications, somatomotoric development and conduit status. Methods and results: Between 11/95 and 12/02 ECFO was performed in 30 children under 4 years of age and 21 older children aged 4–13 years. There were no deaths in children under 4 years of age and two older children died. No prolonged support (>72 h) of suprarenin was required in small children compared to 4 older children. In twenty-seven children, who underwent postoperative heart catheterization no pulmonary artery or systemic vein distortion occurred. One re-operation and one transcatheter intervention were performed because of the partial conduit stenosis. During the median follow-up of 4.8 years a manifestly accelerated postoperative weight gain was observed in children operated on under 4 years of age, compared to that in older children (up to the 50 vs. 10th percentile, P<0.05). Conclusions: The ECFO could be performed in young children with low morbidity and mortality rates. In the majority of patients, implanted prosthetic grafts maintain stable form without the development of stenosis. Accelerated somatic development, especially in small children, is to be observed after completion of the Fontan circulation.     

Loss of CD95 expression is linked to most but not all p53 mutants in European hepatocellular carcinoma

Experimental data have shown p53-dependent CD95 induction to be associated with increased levels of apoptosis after cytostatic treatment in hepatoma cells. A study of Japanese hepatocellular carcinoma (HCC) has reported an inverse correlation between CD95 and p53 expression. To examine the interaction of p53 and CD95 in tumors we investigated which alterations in p53 can be linked to loss of CD95 expression in European HCC. In 39 tumors we analyzed CD95 by immunohistochemistry and assessed the correlation between the findings of the p53 status as determined by immunohistochemistry and single-strand conformation polymorphism with polymerase chain reaction sequencing. In 10 of 14 tumors with evidence of p53 aberration there was also loss of CD95 expression, compared to 6 of 25 samples with apparent wild-type p53 (P<0.01). Three tumors with p53 mutations but sustained CD95 expression showed single base substitutions mapping to a narrow region of 20 codons in p53. A significant correlation with differentiation status of the tumor was found for the p53 aberration but not for CD95 expression. This is the first study to link loss of CD95 expression to specific p53 alterations in HCC. Functional p53 appears to be a major factor for CD95 expression in hepatocytes, the loss of which could contribute to chemoresistance and possibly immune evasion in hepatocellular carcinoma. Sustained CD95 expression in tumors with certain p53 aberrations may indicate functional heterogeneity of p53 mutants.