Vascular endothelial growth factor-A and aldosterone: relevance to normal pregnancy and preeclampsia

Aldosterone levels are markedly elevated during normal pregnancy but fall even though volume contracts when preeclampsia occurs. The level of aldosterone in either condition cannot be explained solely by the activity of the renin-angiotensin II system. In normal gestation, vascular endothelial growth factor (VEGF) is thought to maintain vascular health, but its role in adrenal hormone production is unknown. We hypothesized that the role of VEGF in the adrenal gland is to maintain vascular health and regulate aldosterone production. Here, we demonstrate that supernatant of endothelial cells grown in the presence of VEGF enhanced aldosterone synthase activity in human adrenocortical cells. VEGF either alone or combined with angiotensin II increased aldosterone production in adrenal cells. These data suggest that endothelial cell-dependent and independent activation of aldosterone is regulated by VEGF. In contrast to angiotensin II, VEGF did not upregulate the steroidogenic acute regulatory protein. Consistent with this observation, angiotensin II stimulated both aldosterone and cortisol synthesis from progesterone, whereas VEGF stimulated selectively aldosterone production. In rats, overexpression of soluble fms-like tyrosine kinase-1, an endogenous VEGF inhibitor, led to adrenocortical capillary rarefaction and fall in aldosterone concentrations that correlated inversely with soluble fms-like tyrosine kinase-1 levels. These findings may explain why aldosterone increases so markedly during normal gestation and why preeclampsia, a condition characterized by high soluble fms-like tyrosine kinase-1, is associated with inappropriately low aldosterone levels in spite of relatively lower plasma volumes.

Mycophenolate acid inhibits endothelial NAD(P)H oxidase activity and superoxide formation by a Rac1-dependent mechanism

Endothelial dysfunction precedes hypertension and atherosclerosis and predicts cardiac allograft vasculopathy and death in heart transplant recipients. Endothelial overproduction of reactive oxygen species, such as superoxide anions produced by NAD(P)H oxidase, induces endothelial dysfunction. Because immunosuppressive drugs have been associated with increased reactive oxygen species production and endothelial dysfunction, we sought to elucidate the underlying mechanisms. Reactive oxygen species, release of superoxide anions, and NAD(P)H oxidase activity were studied in human umbilical vein endothelial cells and in polymorphonuclear neutrophils. Gp91ds-tat was used to specifically block NAD(P)H oxidase. Transcriptional activation of different subunits of NAD(P)H oxidase was assessed by real-time RT-PCR. Rac1 subunit translocation and activation were studied by membrane fractionation and pull-down assays. Calcineurin inhibitors significantly increased endothelial superoxide anions production because of NAD(P)H oxidase, whereas mycophenolate acid (MPA) blocked it. MPA also attenuated the respiratory burst induced by neutrophil NAD(P)H oxidase. Because transcriptional activation of NAD(P)H oxidase was not affected, but addition of guanosine restored endothelial superoxide anions formation after MPA treatment, we speculate that the inhibitory effect of MPA was mediated by depletion of cellular guanosine triphosphate content. This prevented activation of Rac1 and, thus, of endothelial NAD(P)H oxidase. Because all heart transplant recipients are at risk for cardiac allograft vasculopathy development, these differential effects of immunosuppressants on endothelial oxidative stress should be considered in the choice of immunosuppressive drugs.

Randomized placebo-controlled trial of ursodeoxycholic acid with vitamin e in nonalcoholic steatohepatitis

BACKGROUND ; AIMS: Nonalcoholic steatohepatitis (NASH) is a frequent liver disease that can progress to cirrhosis and for which there is no recognized therapy. UDCA and vitamin E have been considered separately as therapeutic options and have not been shown to be effective. This study tested their combination. METHODS: Patients with elevated aminotransferase levels and drinking less than 40 g alcohol/week with biopsy-proven NASH were randomly assigned to receive UDCA 12-15 mg.kg-1.day-1 with vitamin E 400 IU twice a day (UDCA/Vit E), UDCA with placebo (UDCA/P), or placebo/placebo (P/P). After 2 years, they underwent a second liver biopsy. Biopsy specimens were collected, blinded, and scored by a single liver pathologist. RESULTS: Forty eight patients were included, 15 in the UDCA/Vit E group, 18 in the UDCA/P group, and 15 in the P/P group; 8 patients dropped out, none because of side effects. Baseline parameters were not significantly different between the 3 groups. Body mass index remained unchanged during the study. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels diminished significantly in the UDCA/Vit E group. Neither the AST nor the ALT levels improved in the P/P group and only the ALT levels in the UDCA/P group. Histologically, the activity index was unchanged at the end of the study in the P/P and UDCA/P groups, but it was significantly better in the UDCA/Vit E group, mostly as a result of regression of steatosis. CONCLUSIONS: Two years of treatment with UDCA in combination with vitamin E improved laboratory values and hepatic steatosis of patients with NASH. Larger trials are warranted.

Hint2, a mitochondrial apoptotic sensitizer down-regulated in hepatocellular carcinoma

BACKGROUND ; AIMS: Hints, histidine triad nucleotide-binding proteins, are adenosine monophosphate-lysine hydrolases of uncertain biological function. Here we report the characterization of human Hint2. METHODS: Tissue distribution was determined by real-time quantitative polymerase chain reaction and immunoblotting, cellular localization by immunocytochemistry, and transfection with green fluorescent protein constructs. Enzymatic activities for protein kinase C and adenosine phosphoramidase in the presence of Hint2 were measured. HepG2 cell lines with Hint2 overexpressed or knocked down were established. Apoptosis was assessed by immunoblotting for caspases and by flow cytometry. Tumor growth was measured in SCID mice. Expression in human tumors was investigated by microarrays. RESULTS: Hint2 was predominantly expressed in liver and pancreas. Hint2 was localized in mitochondria. Hint2 hydrolyzed adenosine monophosphate linked to an amino group (AMP-pNA; k(cat):0.0223 s(-1); Km:128 micromol/L). Exposed to apoptotic stress, fewer HepG2 cells overexpressing Hint2 remained viable (32.2 +/- 0.6% vs 57.7 +/- 4.6%), and more cells displayed changes of the mitochondrial membrane potential (87.8 +/- 2.35 vs 49.7 +/- 1.6%) with more cleaved caspases than control cells. The opposite was observed in HepG2 cells with knockdown expression of Hint2. Subcutaneous injection of HepG2 cells overexpressing Hint2 in SCID mice resulted in smaller tumors (0.32 +/- 0.13 g vs 0.85 +/- 0.35 g). Microarray analyses revealed that HINT2 messenger RNA is downregulated in hepatocellular carcinomas (-0.42 +/- 0.58 log2 vs -0.11 +/- 0.28 log2). Low abundance of HINT2 messenger RNA was associated with poor survival. CONCLUSION: Hint2 defines a novel class of mitochondrial apoptotic sensitizers down-regulated in hepatocellular carcinoma.

Cytokine and anti-cytokine therapy for asthma

Cytokines play a critical role in the pathogenesis of asthma. Asthma resolution may depend on the correction of dysregulated cytokine expression, which is a characteristic feature of this chronic inflammatory disease. It is, therefore, not surprising that attempts have been made to either block cytokines present at elevated levels or to substitute cytokines that are insufficiently expressed in asthma. In this article, the results of these studies are discussed, and the obtained insights regarding asthma pathogenesis and new treatment options are summarized.

Correlates of self-reported nonadherence to antiretroviral therapy in HIV-infected patients: the Swiss HIV Cohort Study

BACKGROUND: Adherence is one of the most crucial issues in the clinical management of HIV-infected patients receiving antiretroviral therapy (ART). METHODS: A 2-item adherence questionnaire was introduced into the Swiss HIV Cohort Study in July 2003. All 3607 eligible patients were on ART for > or =6 months and their current regimen for > or =1 month. Three definitions of nonadherence were considered: missing > or =1 dose, missing > or =2 doses, and taking <95% of doses in the past 4 weeks. RESULTS: Over 30% of patients reported missing > or =1 dose, 14.9% missed > or =2 doses, and 7.1% took <95% of doses in the previous 4 weeks. The rate of drug holidays was 5.8%. Whether using more or less conservative definitions of nonadherence, younger age, living alone, number of previous regimens, and boosted protease inhibitor regimens were independent factors associated with nonadherence. There was a significant association between optimal viral suppression and nonadherence as well as a significant linear trend in optimal viral suppression by missed doses. CONCLUSIONS: Younger age, lack of social support, and complexity of therapy are important factors that are related to nonadherence with ART. Investment in behavioral dimensions of HIV is crucial to improve adherence in ART recipients.

Strategies to prevent neuronal damage in paediatric bacterial meningitis

PURPOSE OF REVIEW: The mortality of bacterial meningitis can reach 30%, and up to 50% of survivors suffer from persisting neurological deficits as a consequence of the disease. The incidence of neurological sequelae of bacterial meningitis has not improved over the last decade. Adjunctive therapeutic options are limited, and ongoing research into the pathophysiology of brain damage in bacterial meningitis aims at providing the scientific basis for future development of more efficient adjunctive options. RECENT FINDINGS: In a population with good access to health care, dexamethasone given before or at the time of initiation of antibiotic therapy acts beneficially in paediatric pneumococcal meningitis, but not in meningococcal meningitis. In experimental animal models, brain-derived neurotrophic factor protected against brain injury and improved hearing while melatonin, which has antioxidant properties among other effects, reduced neuronal death. Transgene technology can be used to provide new insights into the pathophysiology of the disease and to identify potential therapeutic targets. SUMMARY: Although dexamethasone improves outcome of bacterial meningitis under defined circumstances, the morbidity of bacterial meningitis still remains unacceptably high. Experimental models may help to identify new therapeutic strategies to further improve the neurological outcome in young children suffering from bacterial meningitis.

Frequency of gynecologic follow-up and cervical cancer screening in the Swiss HIV cohort study

BACKGROUND: According to current recommendations, HIV-infected women should have at least 1 gynecologic examination per year. OBJECTIVES: To analyze factors associated with frequency of gynecologic follow-up and cervical cancer screening among HIV-infected women followed in the Swiss HIV Cohort Study (SHCS). METHODS: Half-yearly questionnaires between April 2001 and December 2004. At every follow-up visit, the women were asked if they had had a gynecologic examination and a cervical smear since their last visit. Longitudinal models were fitted with these variables as outcomes. RESULTS: A total of 2186 women were included in the analysis. Of the 1146 women with complete follow-up in the SHCS, 35.3% had a gynecologic examination in each time period, whereas 7.4% had never gone to a gynecologist. Factors associated with a poor gynecologic follow-up were older age, nonwhite ethnicity, less education, underweight, obesity, being sexually inactive, intravenous drug use, smoking, having a private infectious disease specialist as a care provider, HIV viral load <400 copies/mL, and no previous cervical dysplasia. No association was seen for living alone, CD4 cell count, and positive serology for syphilis. CONCLUSIONS: Gynecologic care among well-followed HIV-positive women is poor and needs to be improved.

Extended CT scale overcomes restoration caused streak artifacts for dental identification in CT--3D color encoded automatic discrimination of dental restorations

OBJECTIVE: Besides DNA, dental radiographs play a major role in the identification of victims in mass casualties or in corpses with major postmortem alterations. Computed tomography (CT) is increasingly applied in forensic investigations and is used to scan the dentition of deceased persons within minutes. We investigated different restoration materials concerning their radiopacity in CT for dental identification purposes. METHODS: Extracted teeth with different filling materials (composite, amalgam, ceramic, temporary fillings) were CT scanned. Radiopacities of the filling materials were analyzed in extended CT scale images. RESULTS: Radiopacity values ranged from 6000-8500HU (temporary fillings), 4500-17000HU (composite fillings) and >30710HU (Amalgam and Gold). The values were used to define presets for a 3D colored volume rendering software. CONCLUSIONS: The effects of filling material caused streak artifacts could be distinctively reduced for the assessment of the dental status and a postprocessing algorithm was introduced that allows for 3D color encoded visualization and discrimination of different dental restorations based on postmortem CT data.

Noninvasive estimation of organ weights by postmortem magnetic resonance imaging and multislice computed tomography

OBJECTIVE: Computed tomography (CT) and magnetic resonance imaging (MRI) are introduced as an alternative to traditional autopsy. The purpose of this study was to investigate their accuracy in mass estimation of liver and spleen. METHODS: In 44 cases, the weights of spleen and liver were estimated based on MRI and CT data using a volume-analysis software and a postmortem tissue-specific density factor. In a blinded approach, the results were compared with the weights noted at autopsy. RESULTS: Excellent correlation between estimated and real weights (r = 0.997 for MRI, r = 0.997 for CT) was found. Putrefaction gas and venous air embolism led to an overestimation. Venous congestion and drowning caused higher estimated weights. CONCLUSION: Postmortem weights of liver and spleen can accurately be assessed by nondestructive imaging. Multislice CT overcomes the limitation of putrefaction and venous air embolism by the possibility to exclude gas. Congestion seems to be even better assessed.

Arterial stiffness assessed by digital volume pulse correlates with comorbidity in patients with ESRD

BACKGROUND: Digital volume pulse (DVP), a noninvasive method for indirect assessment of arterial stiffness, was not tested previously in patients with end-stage renal disease (ESRD). Therefore, we compared the DVP-derived stiffness index (SI(DVP)) with aortic pulse wave velocity (PWV) determined by means of Doppler ultrasonography in 2 groups of patients with ESRD and analyzed the correlation between SI(DVP) and comorbidity. METHODS: Photoplethysmography was performed on the index finger of the dominant hand or the hand from the nonfistula arm in 49 renal transplant (TX) recipients and 48 hemodialysis (HD) patients. Pulse curves were analyzed with computer assistance. Comorbidity was assessed by using an established index. RESULTS: The intrasubject variability of SI(DVP) was 5.7%. SI(DVP) and aortic PWV values correlated significantly (r = 0.66; P = 0.001) in patients with ESRD. SI(DVP) could not be assessed reliably in 25% and 6% of HD patients and TX recipients, respectively. Multivariate regression analyses showed that SI(DVP) increased with age in both HD patients and TX recipients (r = 0.61; P < 0.001) and with systolic blood pressure (r = 0.53; P < 0.025), mean arterial pressure (r = 0.47; P < 0.05), and pulse pressure (r = 0.52; P = 0.02) in TX recipients. Severity of comorbid status was associated highly with individual residuals of age-adjusted SI(DVP) in HD patients and TX recipients (P < 0.001). CONCLUSION: DVP allows the measurement of arterial stiffness in most, but not all, patients with ESRD. SI(DVP) values correlate with comorbidity in HD patients and TX recipients.