Human Protein Reference Database and Human Proteinpedia as discovery tools for systems biology

Although high-throughput technologies used in biology have resulted in the accumulation of vast amounts of data in the literature, it is becoming difficult for individual investigators to directly benefit from this data because they are not easily accessible. Databases have assumed a crucial role in assimilating and storing information that could enable future discoveries. To this end, our group has developed two resources - Human Protein Reference Database (HPRD) and Human Proteinpedia - that provide integrated information pertaining to human proteins. These databases contain information on a number of features of proteins that have been discovered using various experimental methods. Human Proteinpedia was developed as a portal for community participation to annotate and share proteomic data using HPRD as the scaffold. It allows proteomic investigators to even share unpublished data and provides an effective medium for data sharing. As proteomic information reflects a direct view of cellular systems, proteomics is expected to complement other areas of biology such as genomics, transcriptomics, classical genetics, and chemical genetics in understanding the relationships among genome, gene functions, and living systems.

Dysregulation of vascular TRPM7 and annexin-1 is associated with endothelial dysfunction in inherited hypomagnesemia

Inadequate magnesium intake and hypomagnesemia may contribute to chronic diseases, such as hypertension. The novel magnesium transporter TRPM7 is a critical regulator of magnesium homeostasis in vascular cells, but its role in pathophysiology is unclear. In a model of hypomagnesemia, we examined microvascular structure and function, TRPM7 expression, and vascular inflammatory status using inbred mice selected for normal-high intracellular magnesium levels or low intracellular magnesium levels (MgLs). Blood pressure was significantly increased in MgLs compared with normal-high intracellular magnesium levels. Pressurized myography of mesenteric resistance arteries showed that MgLs had significantly impaired endothelial function together with decreased plasma nitrate levels and endothelial NO synthase expression when compared with normal-high intracellular magnesium levels. Significant differences in vascular structure were also evident in both mesenteric arteries and aortas from MgLs. Aortas from MgLs had increased medial cross-sectional areas, whereas mesenteric arteries from MgLs had increased lumen diameters with increased medial cross-sectional areas, indicating outward hypertrophic remodeling. Expression of the magnesium transporter TRPM7 was significantly elevated in the vasculature of MgLs, whereas expression of a TRPM7 downstream target, the anti-inflammatory molecule annexin-1, was reduced. MgLs had increased expression of vascular cell adhesion molecule-1 and plasminogen activator inhibitor-1, indicating vascular inflammation. Taken together, these data demonstrate that the inherited magnesium status of MgLs and normal-high intracellular magnesium levels mice affects magnesium transporter expression, endothelial function, vascular structure, and inflammation. Our findings suggest a potential regulatory role for TRPM7 signaling in the maintenance of vascular integrity. Alterations in magnesium status and/or TRPM7 signaling may contribute to vascular injury in conditions associated with hypomagnesemia.

Predictors of survival of advanced renal cell carcinoma: long-term results from Southwest Oncology Group Trial S8949

PURPOSE

S8949 demonstrated improved overall survival for debulking nephrectomy in interferon treated patients with advanced renal cell carcinoma. We present an updated analysis of S8949, now with a median followup of 9 years. We explored clinical predictors of overall survival.

MATERIALS AND METHODS

Univariate and multivariate Cox regression analysis was performed to evaluate the impact of clinical variables potentially influencing survival.

RESULTS

Of 246 patients 241 were eligible and randomized to interferon with or without nephrectomy. Patients randomized to nephrectomy continued to have improved overall survival (HR 0.74, 95% CI 0.57-0.96, p = 0.022). Multivariate analysis showed that performance status 1 vs 0 (HR 1.95, p <0.0001), high alkaline phosphatase (HR 1.5, p = 0.002) and lung metastasis only (HR 0.73, p = 0.028) were overall survival predictors. There was no evidence of an interaction of performance status, measurable disease or lung metastases with nephrectomy (each p >0.30). In a patient subset that survived at least 90 days after randomization early progressive disease within 90 days was prognostic of overall survival in a multivariate model (HR 2.1, p <0.0001), as was performance status (HR 1.7, p = 0.0006).

CONCLUSIONS

Nephrectomy prolonged long-term overall survival in this updated analysis, supporting its role as standard therapy in patients with advanced renal cell carcinoma. A nephrectomy benefit was seen across all prespecified patient subsets. Early progressive disease and performance status were strong predictors of overall survival. These results support efforts to identify biomarkers of renal cell carcinoma resistance to treatment and early progressive disease to facilitate rational patient selection for systemic therapy.

Decoy receptor 3 is a prognostic factor in renal cell cancer

BACKGROUND

Decoy receptor 3 (DcR3) is a soluble protein that binds to and inactivates the death ligand CD95L. Here, we studied a possible association between DcR3 expression and prognosis in patients with renal cell carcinomas (RCCs).

METHODS

A tissue microarray containing RCC tumor tissue samples and corresponding normal tissue samples was generated. Decoy receptor 3 expression in tumors of 560 patients was examined by immunohistochemistry. The effect of DcR3 expression on disease-specific survival and progression-free survival was assessed using univariate analysis and multivariate Cox regression analysis. Decoy receptor 3 serum levels were determined by ELISA.

FINDINGS

High DcR3 expression was associated with high-grade (P = .005) and high-stage (P = .048) RCCs. The incidence of distant metastasis (P = .03) and lymph node metastasis (P = .002) was significantly higher in the group with high DcR3 expression. Decoy receptor 3 expression correlated negatively with disease-specific survival (P < .001) and progression-free survival (P < .001) in univariate analyses. A multivariate Cox regression analysis retained DcR3 expression as an independent prognostic factor that outperformed the Karnofsky performance status. In patients with high-stage RCCs expressing DcR3, the 2-year survival probability was 25%, whereas in patients with DcR3-negative tumors, the survival probability was 65% (P < .001). Moreover, DcR3 serum levels were significantly higher in patients with high-stage localized disease (P = .007) and metastatic disease (P = .001).

INTERPRETATION

DcR3 expression is an independent prognostic factor of RCC progression and mortality. Therefore, the assessment of DcR3 expression levels offers valuable prognostic information that could be used to select patients for adjuvant therapy studies.

Effects of serum homocysteine and adiponectin levels on platelet aggregation in untreated patients with essential hypertension

The aim of the present study is to determine and correlate adiponectin, homocysteine, nitric oxide, and ADP-induced platelet aggregation levels in untreated patients with essential hypertension and healthy individuals. A total of 36 individuals, 23 untreated patients with essential hypertension and 13 healthy individuals, were included in the scope of this study. Enzyme-linked immunosorbent assay (ELISA) was used to determine the serum adiponectin and TNF-alpha levels. The levels of serum homocysteine were measured by using competitive chemiluminescent enzyme immunoassay. Serum concentrations of hsCRP were measured by the Nephelometer. Plasma nitrite, nitrate, and total nitric oxide (NOx) levels were determined by colorimetric method. Homocysteine and hsCRP levels in patients with essential hypertension were found to be significantly higher than those in the control group (P = 0.02, P = 0.001, respectively). The average platelet aggregation levels in patient group were higher than control group, but there were no statistically significant differences between them (P > 0.05). In addition, in patients with essential hypertension adiponectin and nitrite levels are significantly lower than control group (P < 0.001, P = 0.045, respectively). We have also found significant correlations between nitrite-platelet aggregation amplitude, nitrite-platelet aggregation slope, nitrite-adiponectin, homocysteine-platelet aggregation amplitude, and sistolic blood pressure-platelet aggregation amplitude levels (r = -0.844; P < 0.001, r = -0.680; P = 0.011, r = 0.454; P = 0.05, r = 0.414; P = 0.05, r = 0.442; P = 0.035, respectively). Increased homocysteine and decreased adiponectin serum levels in patients with essential hypertension correlate well with changes in ADP-induced conventional platelet aggregation. This association may potentially contribute to future thrombus formation and higher risks for cardiovascular events in hypertensive patients.

Oxidative stress in prehypertension: rationale for antioxidant clinical trials

Prehypertension has been recently described as an independent category of blood pressure. Mounting evidence suggests that blood pressure in the prehypertensive range is associated with an increased risk of developing hypertension and cardiovascular disease. Several reports have assigned a critical role for oxidative stress in these disease processes. This review focuses on the clinical and experimental studies done in prehypertension and hypertension within the context of oxidative stress. This article also provides insights into why diverse therapeutic interventions, which have in common the ability to reduce oxidative stress, can impede or delay the onset of hypertension in prehypertension subjects.

Gender specific association of endothelial nitric oxide synthase gene (Glu298Asp) polymorphism with essential hypertension in a south Indian population

BACKGROUND

Endothelial derived nitric oxide (NO) plays a major role in blood pressure regulation. The role of missense variant eNOS-Glu298Asp has been demonstrated by many studies with conflicting results. Our objective was to investigate the association of eNOS gene polymorphism with essential hypertension in a south Indian population.

METHODS

We carried out a case control study in 438 hypertensive patients and 444 healthy control subjects in a homogenous population. Genotyping was done by PCR-RFLP method. Multiple logistic regression analysis was used to detect the association between genotype and hypertension.

RESULTS

The homozygous variant genotype Asp298Asp was significantly associated with hypertension (odds ratio 2.4; 95% CI, 1.23-5.0, p<0.01). Gender specific analysis showed both the heterozygous (odds ratio, 2.0; 95% CI, 1.3-2.9, p<0.01) and homozygous variants (odds ratio, 7.9; 95% CI, 2.0-4.1, p<0.001) were positively associated with hypertension in females. The variant allele Asp was higher in female hypertensives when compared to male hypertensive cases (22% vs. 16%).

CONCLUSION

The eNOS gene polymorphism is a candidate gene for hypertension and the association to be gender specific with respect to females in a south Indian Tamilian population.

Targeting reactive oxygen species in hypertension

Oxidative stress plays an important role in the pathogenesis of hypertension. A number of sources of reactive oxygen species have been identified including NADPH oxidase, endothelial NO synthase, and xanthine oxidase. Inhibitors of these systems reduce blood pressure in experimental models. Targeted overexpression of antioxidant systems and interference with expression of oxidant systems has also been successfully used in animal models of hypertension. It is expected that these strategies will eventually be translated to human disease, but currently, the specificity and toxicity of such measures are not yet fulfilling quality criteria for treatment of humans. In the meantime, presumably nontoxic measures, such as administration of antioxidant vitamins, are the only available treatments for oxidative stress in humans. In this review, we discuss strategies to target oxidative stress both in experimental models and in humans. We also discuss how patients could be selected who particularly benefit from antioxidant treatment. In clinical practice, diagnostic procedures beyond measurement of blood pressure will be necessary to predict the response to antioxidants; these procedures will include measurement of antioxidant status and detailed assessment of vascular structure and function.

Plasma matrix metalloproteinase-7 as a metastatic marker and survival predictor in patients with renal cell carcinomas

We evaluated the clinical usefulness of plasma matrix metalloproteinase-7 (MMP-7) as a diagnostic and prognostic biomarker in patients with renal cell carcinoma (RCC). MMP-7 was quantified in plasma of 50 healthy subjects and 97 RCC patients using a Fluorokine MultiAnalyte Profiling assay. RCC patients were stratified into the following groups: without metastases (N0M0; n = 39), with lymph nodes (N1M0; n = 13), and with distant metastases (M1; n = 45). Diagnostic performance of MMP-7 was analyzed by the receiver operating characteristics (ROC) curve. Kaplan-Meier analysis and the Cox regression model were used to estimate the impact of MMP-7 on the cancer-specific survival outcome of RCC patients. MMP-7 was significantly higher in both metastatic groups N1M0 and M1 (medians, 3.82 and 3.34 microg/L) compared to N0M0 group or controls (medians, 1.85 and 1.64 microg/L; all P < 0.001). In ROC analysis, the area under the ROC curve of MMP-7 was 0.80 in the detection of metastases in RCC (P < 0.0001). In the Kaplan-Meier analysis, patients with MMP-7 above the 95th percentile of controls showed less favorable survival rates compared to those with normal MMP-7 (log-rank test, 15.7; P < 0.0001). High MMP-7 was associated with cancer-related mortality estimated by univariate Cox regression (risk ratio, 4.34, 95% CI, 1.12-10.6; P = 0.032). The multivariate Cox regression model determined MMP-7 (risk ratio, 2.70, 95% CI, 1.39-5.24; P = 0.003) and metastases (risk ratio, 5.81, 95% CI, 2.77-12.2; P < 0.0001) as independent determinants of cancer-related survival outcomes. In conclusion, increased plasma MMP-7 could be related to metastatic disease and poor prognosis in patients with RCC.

Relationship between oxidative stress and essential hypertension

This study investigated the association of blood pressure with blood oxidative stress-related parameters in normotensive and hypertensive subjects. A cross-sectional design was applied to 31 hypertensive patients and 35 healthy normotensive subjects. All subjects were men between the ages of 35 and 60 years. Exclusion criteria were obesity, dyslipidemia, diabetes mellitus, smoking and current use of any medication. All patients underwent 24-h ambulatory blood pressure monitoring and sampling of blood and urine. Antioxidant enzymes activity, reduced/oxidized glutathione ratio (GSH/GSSG), and lipid peroxidation (malondialdehyde) were determined in erythrocytes. Parameters measured in the plasma of test subjects were plasma antioxidant status, lipid peroxidation (8-isoprostane), plasma vitamin C and E, and the blood pressure modulators renin, aldosterone, endothelin-1 and homocysteine. Daytime systolic and diastolic blood pressures of hypertensives were negatively correlated with plasma antioxidant capacity (r=-0.46, p<0.009 and r=-0.48, p<0.007), plasma vitamin C levels (r=-0.53, p<0.003 and r=-0.44, p<0.02), erythrocyte activity of antioxidant enzymes, and erythrocyte GSH/GSSG ratio, with hypertensives showing higher levels of oxidative stress. Blood pressures showed a positive correlation with both plasma and urine 8-isoprostane. Neither plasma vitamin E nor the assessed blood pressure modulator levels showed significant differences between the groups or correlation with blood pressures. These findings demonstrate a strong association between blood pressure and some oxidative stress-related parameters and suggest a possible role of oxidative stress in the pathophysiology of essential hypertension.

Diagnostic and prognostic molecular markers in renal cell carcinoma

PURPOSE

We reviewed the contemporary literature on molecular biomarkers in renal cell carcinoma and their prognostic significance.

MATERIALS AND METHODS

Articles published during 1981 to 2007 in English on renal cell carcinoma were surveyed using the MEDLINE/PubMed database. The subject headings included were genetics, biomarkers, prognosis and risk models of renal cell carcinoma. We present a synthesis of currently known renal cell carcinoma biomarkers at various stages of development and their clinical significance, and prognostic nomograms incorporating biomarkers.

RESULTS

The beneficiary role of biomarkers in renal cell carcinoma is challenged by the relatively low prevalence of the disease. Even if a biomarker for renal cell carcinoma had 100% sensitivity and 99.4% specificity, the positive predictive value of the marker in men older than 65 years would be only 10%. Several biomarkers are being investigated in renal cell carcinoma, of which many relate to pathogenic molecular changes that are currently therapeutic targets. Carbonic anhydrase IX is a von Hippel-Lindau mediated enzyme that is expressed in most renal cell carcinoma cases. High (greater than 85%) expression of this marker indicates favorable prognosis and may predict the response to interleukin-2 therapy. B7-H1 expression in renal cell carcinoma cells/lymphocytes may indicate worse survival, possibly through impaired host antitumor immunity. Prognostic nomograms incorporating clinical variables and molecular markers to refine the prediction of treatment outcomes are in active development and await prospective clinical validation.

CONCLUSIONS

Several renal cell carcinoma molecular markers appear promising to refine the prognosis and prediction of localized, advanced or metastatic renal cell carcinoma. Currently carbonic anhydrase IX is the best studied and promising marker. Prospective, multicenter clinical validation aimed at the practical clinical usefulness of renal cell carcinoma biomarkers is warranted.

Transient receptor potential melastatin 6 and 7 channels, magnesium transport, and vascular biology: implications in hypertension

Magnesium, an essential intracellular cation, is critically involved in many biochemical reactions involved in the regulation of vascular tone and integrity. Decreased magnesium concentration has been implicated in altered vascular reactivity, endothelial dysfunction, vascular inflammation, and structural remodeling, processes important in vascular changes and target organ damage associated with hypertension. Until recently, very little was known about mechanisms regulating cellular magnesium homeostasis, and processes controlling transmembrane magnesium transport had been demonstrated only at the functional level. Two cation channels of the transient receptor potential melastatin (TRPM) cation channel family have now been identified as magnesium transporters, TRPM6 and TRPM7. These unique proteins, termed chanzymes because they possess a channel and a kinase domain, are differentially expressed, with TRPM6 being found primarily in epithelial cells and TRPM7 occurring ubiquitously. Vascular TRPM7 is modulated by vasoactive agents, pressure, stretch, and osmotic changes and may be a novel mechanotransducer. In addition to its magnesium transporter function, TRPM7 has been implicated as a signaling kinase involved in vascular smooth muscle cell growth, apoptosis, adhesion, contraction, cytoskeletal organization, and migration, important processes involved in vascular remodeling associated with hypertension and other vascular diseases. Emerging evidence suggests that vascular TRPM7 function may be altered in hypertension. This review discusses the importance of magnesium in vascular biology and implications in hypertension and highlights the transport systems, particularly TRPM6 and TRPM7, which may play a role in the control of vascular magnesium homeostasis. Since the recent identification and characterization of Mg2+-selective transporters, there has been enormous interest in the field. However, there is still a paucity of information, and much research is needed to clarify the exact mechanisms of magnesium regulation in the cardiovascular system and the implications of aberrant transmembrane magnesium transport in the pathogenesis of hypertension and other vascular diseases.

An association study of sodium-lithium countertransport activity with glutathione S transferase (GST) T1 and GST M1 null polymorphisms in Greek dyslipidaemic patients and controls

BACKGROUND

Previous genomic linkage studies have produced evidence linking sodium-lithium countertransport activity (Na/Li CT) with various chromosomal regions including loci harbouring glutathione S transferase (GST) genes. The aim of this study was to examine the putative association of erythrocyte Na/Li CT activity with GST T1 and M1 gene null polymorphisms.

METHODS

Na/Li CT activity was determined in erythrocytes isolated from 85 individuals, using a standard assay procedure employing atomic absorption spectroscopy. Genotyping of the GST T1 and GST M1 null polymorphisms was accomplished with a multiplex PCR method. A general linear model using age, sex, smoking, dyslipidaemia and hypertension as covariates was used to examine the association of Na/Li CT activity with the GST T1 and GST M1 genotypes.

RESULTS

Individuals with the GST T1 null genotype displayed marginally significantly (p=0.049) lower values of Na/Li CT activity compared to those harbouring at least one copy of the GST T1 gene. The significance of this association was eliminated following adjustment for covariates (p=0.150), but survived as a trend when the sample was limited to normotensive and normolipidaemic individuals (p=0.070). No association was detected between the GST M1 null polymorphism and Na/Li CT activity.

CONCLUSIONS

The suggestive association of the GST T1 null polymorphism with erythrocyte Na/Li CT activity is in line with previously published data from genetic linkage and biochemical analyses and may be of potential prognostic value as regards the behaviour of the countertransport and the development of related pathologies under conditions of oxidative insult.

Wnt antagonist family genes as biomarkers for diagnosis, staging, and prognosis of renal cell carcinoma using tumor and serum DNA

PURPOSE

We hypothesized that combined methylation analysis of Wnt antagonist genes could serve as a panel of biomarkers for diagnosis, staging, and prognosis in renal cell carcinoma (RCC).

EXPERIMENTAL DESIGN

Samples (n = 62) of RCC and corresponding normal renal tissue (NRT) were analyzed using methylation-specific PCR for methylation of six Wnt antagonist genes (sFRP-1, sFRP-2, sFRP-4, sFRP-5, Wif-1, and Dkk-3). To increase the sensitivity/specificity of RCC detection, the methylation score (M score) for multigene methylation analysis was developed. Receiver operator characteristic curve analysis was used to determine the optimal sensitivity/specificity of the M score. In addition, the M score was compared with the clinicopathologic outcome. Thirty-three serum DNA samples were also used to investigate the methylation status of Wnt antagonist genes.

RESULTS

The methylation levels of all Wnt antagonists were significantly higher in RCC than in NRT. In multivariate regression analysis, the methylation level of sFRP-1 was a significant independent predictor of RCC, whereas for sFRP-2 and sFRP-4 there was a trend toward significance as independent predictors. The M score of Wnt antagonist genes was significantly higher in RCC than in NRT. Overall, the M score had a sensitivity of 79.0% and a specificity of 75.8% (area under the curve, 0.808) as a diagnostic biomarker. In addition, the M score could significantly distinguish grade, pT category, M category, and overall survival of RCC patients. The M score was independent of age and gender in predicting overall survival by the Cox proportional hazards model. In RCC patients, 72.7% of the methylation-specific PCR results had identical methylation in samples of tumor and serum DNA. No serum DNA in normal controls showed aberrant methylation of the Wnt antagonist genes. In addition, the methylation status of Wnt antagonist genes in serum DNA was significantly correlated with tumor grade and stage.

CONCLUSIONS

This is the first report showing that M score analysis of Wnt antagonist genes can serve as an excellent epigenetic biomarker panel for detection, staging, and prognosis of RCC using serum DNA.

Quercetin reduces blood pressure in hypertensive subjects

Epidemiological studies report that quercetin, an antioxidant flavonol found in apples, berries, and onions, is associated with reduced risk of coronary heart disease and stroke. Quercetin supplementation also reduces blood pressure in hypertensive rodents. The efficacy of quercetin supplementation to lower blood pressure in hypertensive humans has never been evaluated. We tested the hypothesis that quercetin supplementation reduces blood pressure in hypertensive patients. We then determined whether the antihypertensive effect of quercetin is associated with reductions in systemic oxidant stress. Men and women with prehypertension (n = 19) and stage 1 hypertension (n = 22) were enrolled in a randomized, double-blind, placebo-controlled, crossover study to test the efficacy of 730 mg quercetin/d for 28 d vs. placebo. Blood pressure (mm Hg, systolic/diastolic) at enrollment was 137 +/- 2/86 +/- 1 in prehypertensives and 148 +/- 2/96 +/- 1 in stage 1 hypertensive subjects. Blood pressure was not altered in prehypertensive patients after quercetin supplementation. In contrast, reductions in (P < 0.01) systolic (-7 +/- 2 mm Hg), diastolic (-5 +/- 2 mm Hg), and mean arterial pressures (-5 +/- 2 mm Hg) were observed in stage 1 hypertensive patients after quercetin treatment. However, indices of oxidant stress measured in the plasma and urine were not affected by quercetin. These data are the first to our knowledge to show that quercetin supplementation reduces blood pressure in hypertensive subjects. Contrary to animal-based studies, there was no quercetin-evoked reduction in systemic markers of oxidative stress.

Factors that regulate embryonic gustatory development

Numerous molecular factors orchestrate the development of the peripheral taste system. The unique anatomy/function of the taste system makes this system ideal for understanding the mechanisms by which these factors function; yet the taste system is underutilized for this role. This review focuses on some of the many factors that are known to regulate gustatory development, and discusses a few topics where more work is needed. Some attention is given to factors that regulate epibranchial placode formation, since gustatory neurons are thought to be primarily derived from this region. Epibranchial placodes appear to arise from a pan-placodal region and a number of regulatory factors control the differentiation of individual placodes. Gustatory neuron differentiation is regulated by a series of transcription factors and perhaps bone morphongenic proteins (BMP). As neurons differentiate, they also proliferate such that their numbers exceed those in the adult, and this is followed by developmental death. Some of these cell-cycling events are regulated by neurotrophins. After gustatory neurons become post-mitotic, axon outgrowth occurs. Axons are guided by multiple chemoattractive and chemorepulsive factors, including semaphorins, to the tongue epithelium. Brain derived neurotrophic factor (BDNF), functions as a targeting factor in the final stages of axon guidance and is required for gustatory axons to find and innervate taste epithelium. Numerous factors are involved in the development of gustatory papillae including Sox-2, Sonic hedge hog and Wnt-β-catenin signaling. It is likely that just as many factors regulate taste bud differentiation; however, these factors have not yet been identified. Studies examining the molecular factors that regulate terminal field formation in the nucleus of the solitary tract are also lacking. However, it is possible that some of the factors that regulate geniculate ganglion development, outgrowth, guidance and targeting of peripheral axons may have the same functions in the gustatory CNS.

In search of suitable reference genes for gene expression studies of human renal cell carcinoma by real-time PCR

Background

Housekeeping genes are commonly used as endogenous reference genes for the relative quantification of target genes in gene expression studies. No conclusive systematic study comparing the suitability of different candidate reference genes in clear cell renal cell carcinoma has been published to date. To remedy this situation, 10 housekeeping genes for normalizing purposes of RT-PCR measurements already recommended in various studies were examined with regard to their usefulness as reference genes.

Results

The expression of the potential reference genes was examined in matched malignant and non-malignant tissue specimens from 25 patients with clear cell renal cell carcinoma. Quality assessment of isolated RNA performed with a 2100 Agilent Bioanalyzer showed a mean RNA integrity number of 8.7 for all samples. The between-run variations related to the crossing points of PCR reactions of a control material ranged from 0.17% to 0.38%. The expression of all genes did not depend on age, sex, and tumour stage. Except the genes TATA box binding protein (TBP) and peptidylprolyl isomerase A (PPIA), all genes showed significant differences in expression between malignant and non-malignant pairs. The expression stability of the candidate reference genes was additionally controlled using the software programs geNorm and NormFinder. TBP and PPIA were validated as suitable reference genes by normalizing the target gene ADAM9 using these two most stably expressed genes in comparison with up- and down-regulated housekeeping genes of the panel.

Conclusion

Our study demonstrated the suitability of the two housekeeping genes PPIA and TBP as endogenous reference genes when comparing malignant tissue samples with adjacent normal tissue samples from clear cell renal cell carcinoma. Both genes are recommended as reference genes for relative gene quantification in gene profiling studies either as single gene or preferably in combination.

Clinical pharmacology and therapeutic use of antioxidant vitamins

The clinical use of antioxidants has gained considerable interest during the last decade. It was suggested from epidemiological studies that diets high in fruits and vegetables might help decrease the risk of cardiovascular disease. Therefore, supplements of vitamins C and E were applied through protocols aimed to prevent diseases such as atherosclerosis, preeclampsia or hypertension, thought to be mediated by oxidative stress. Despite the biological properties of these vitamins could account for an effective protection, as shown by several clinical and experimental studies, their efficacy remains controversial in the light of some recent clinical trials and meta-analyses. However, the methodology of these studies, criteria for selection of patients, the uncertain extent of progression of the disease when initiating supplementation, the lack of mechanistic studies containing basic scientific aspects, such as the bioavailability, pharmacokinetic properties, and the nature of the antioxidant sources of vitamins, could account for the inconsistency of the various clinical trials and meta-analyses assessing the efficacy of these vitamins to prevent human diseases. This review presents a survey of the clinical use of antioxidant vitamins E and C, proposing study models based on the biological effects of these compounds likely to counteract the pathophysiological mechanisms able to explain the structural and functional organ damage.

Effects of Alpha-Lipoic Acid Supplementation in Peripheral Arterial Disease: A Pilot Study

OBJECTIVE

To examine whether 3 months of lipoic acid (LA) supplementation improved walking tolerance and delayed claudication pain onset in peripheral arterial disease (PAD).

DESIGN

Randomized, double-blind, controlled study.

SETTING

General Clinical Research Center.

SUBJECTS

Twenty-eight (28) participants (15 men, 13 women) with PAD (ankle brachial index range 0.9-0.4, mean age 73.2 +/- 1.6 years).

INTERVENTION

LA (600 mg/day) or placebo for 3 months.

OUTCOME MEASURES

Walking tolerance was assessed by 6-minute walk test distance, 4-meter walk time, initial claudication pain time (ICT) and distance (ICD), and peak claudication pain. Serum was assessed for inflammation (C-reactive protein [CRP]) and oxidative stress (lipid hydroperoxides) as potential mechanisms for changes in walking tolerance.

RESULTS

ICT increased 34.4% and 15%, ICD was reduced by 40.5% and 18%, and peak claudication pain ratings were reduced by 93% and 7% in LA and placebo groups, respectively. Although the improvements in peak pain and ICT achieved significance within the LA group (both p<0.05), the interactions of group by time were not found to be significant (p>0.05). Oxidative stress and CRP measures were not different between groups by month 3 (p>0.05). There were no serious side-effects associated with the LA.

CONCLUSIONS

LA may confer pain relief during exercise. However, longer and larger trials are warranted to determine long-term effects of LA alone or combined with other interventions on PAD symptoms.

Elevated plasma osteopontin as marker for distant metastases and poor survival in patients with renal cell carcinoma

PURPOSE

To evaluate diagnostic and prognostic significance of plasma osteopontin (OPN) in patients with renal cell carcinoma (RCC).

METHODS

The retrospective study included 80 patients with RCC (pN0M0, n = 32; pN1M0, n = 11; M1, and n = 37), and 52 healthy controls (27 females and 25 males). OPN, the bone marker bone-specific alkaline phosphatase (bALP) and carboxyterminal telopetide of type-I collagen (ICTP), and the enzymes alanine aminotransferase (ALAT), and gamma-glutamyltransferase (GGT) were evaluated together with Memorial Sloan-Kettering Cancer Center (MSKCC) laboratory parameters. Data were analyzed by receiver-operating characteristics (ROC), survival analysis, and Cox proportional hazards regression model.

RESULTS

OPN and ICTP levels in RCC patients with distant metastases were significantly elevated (medians 115 and 4.7 microg/l, P < 0.001) compared to those without metastases (31.1 and 2.5 microg/l) and controls (28.9 and 2.1 microg/l) but did not differ between patients with bone or non-bone metastases. Both bALP and ALAT were not different between all study groups, while GGT was only increased in patients with non-bone metastases. In ROC analysis, OPN showed the best discrimination between patients with and without metastases (area under the curve: 0.888). High OPN values were associated with poor survival (Kaplan-Meier analysis, log-rank test, P = 0.002). Multivariate Cox regression with forward and backward stepwise elimination confirmed plasma OPN as independent predictive survival factor in RCC patients.

CONCLUSIONS

Our results show that high plasma OPN levels are associated with distant metastases and poor survival in RCC patients. The use of OPN as potential marker to monitor new treatment strategies in patients with advanced RCC should be evaluated in prospective studies.

Renal cell carcinoma: Current status and emerging therapies

Renal cell carcinoma (RCC) accounts for about 3% of all adult malignancies and its incidence is increasing. Smoking, obesity, and end-stage renal disease are important risk factors. Localized RCC may be cured with surgical excision. However, over one-third of patients eventually develop metastatic disease. While chemotherapy and radiation therapy are relatively ineffective for RCC, immunotherapy modestly extends survival and may lead to tumor regression and long-term survival in a small minority of patients. Recently, research into the pathology of genetic syndromes associated with RCC has led to remarkable advances in our understanding of the pathogenesis of sporadic RCC. Rational therapeutic agents developed from this understanding have established new treatment paradigms for this disease.

Relationship between (Na + K)-ATPase activity, lipid peroxidation and fatty acid profile in erythrocytes of hypertensive and normotensive subjects

Oxidative stress may play a role in the pathogenic mechanism of essential hypertension. Lipid peroxidation can alter the cellular structure of membrane-bound enzymes by changing the membrane phospholipids fatty acids composition. We investigated the relationship between (Na + K)-ATPase activity, lipid peroxidation, and erythrocyte fatty acid composition in essential hypertension. The study included 40 essential hypertensive and 49 healthy normotensive men (ages 35-60 years). Exclusion criteria were obesity, dyslipidemia, diabetes mellitus, smoking, and any current medication. Patients underwent 24-h ambulatory blood pressure monitoring and blood sampling. Lipid peroxidation was measured in the plasma and erythrocytes as 8-isoprostane or malondialdehyde (MDA), respectively. Antioxidant capacity was measured as ferric reducing ability of plasma (FRAP) in the plasma and as reduced/oxidized glutathione (GSH/GSSG ratio) in erythrocytes. (Na + K)-ATPase activity and fatty acids were determined in erythrocyte membranes. Hypertensives had higher levels of plasma 8-isoprostane, erythrocyte MDA, and relative percentage of saturated membrane fatty acids, but lower plasma FRAP levels, erythrocyte GSH/GSSG ratio, (Na + K)-ATPase activity and relative percentage of unsaturated membrane fatty acids, compared with normotensives. Day-time systolic and diastolic blood pressures correlated positively with lipid peroxidation parameters, but negatively with (Na + K)-ATPase activity. These findings suggest that the modulation of (Na + K)-ATPase activity may be associated with changes in the fatty acid composition induced by oxidative stress and provide evidence of a role for this enzyme in the pathophysiology of essential hypertension.

Perspectives of proteomics in acute myeloid leukemia

Acute myeloid leukemia (AML) is a frequent hematological malignancy. Despite enormous therapeutic efforts that range from various cytotoxic agents to allogeneic stem cell transplantation, overall survival of patients with AML remains unsatisfying. The poor survival rates are mainly due to therapy-related mortality, failure of induction chemotherapy and early relapses. Therefore, novel therapeutic agents that are more efficient and better tolerated are eagerly sought after. For existing therapeutic strategies, there is a lack of markers that are capable of reliably predicting prognosis or the therapeutic response prior to treatment. There is hope that elucidation of the AML-specific proteome will prompt the discovery of novel therapeutic targets and biomarkers in AML. Modern mass-spectrometry instrumentation has achieved excellent performance in terms of sensitivity, resolution and mass accuracy; however, so far, the contribution of proteomics to the care of patients with AML is virtually zero. This might be partly because mass spectrometry instrumentation and protein fractionation still lack true high-throughput capabilities with highest levels of reproducibility, thus hampering large-scale translational studies with clinical samples. Since mass-spectrometry instruments are very intricate devices, their successful operation will hinge on the willingness and ability of mass-spectrometry experts and clinical researchers to adopt new views, learn from each other and cooperate in order to ultimately benefit the patient suffering from AML. This review highlights some clinical problems circumventing the treatment of patients with AML. Furthermore, it provides a brief overview of the technical background of standard proteomics approaches and describes opportunities, challenges and pitfalls of proteomic studies with regards to AML.

Contribution of different Nox homologues to cardiac remodeling in two-kidney two-clip renovascular hypertensive rats: effect of valsartan

Growing evidences have shown that hypertension, cardiac hypertrophy and fibrosis were associated with an overactivity of NAD(P)H oxidase. It is unknown, however, which isoform of NAD(P)H oxidase yields O(2)*(-) formation in heart and aorta in two-kidney, two-clip (2K2C) hypertensive rats in vivo and thus is responsible for the development of cardiac remodeling. We examined the pathological change of NAD(P)H oxidase homologues and tested the effect of valsartan on the cardiac remodeling in 2K2C renovascular hypertensive rats. Four weeks after male Sprague-Dawley rats accepted 2K2C or sham operation, 2K2C hypertensive (>160 mmHg) rats were divided into vehicle-treated (2K2C) and valsartan (30 mg kg(-1) per day, for 6 weeks)-treated (2K2C+Val) groups, which were compared with sham-operated controls (Sham). At week 10, 2K2C hypertensive rats showed increased serum level of angiotensin II (Ang II), MDA and blood pressure (BP), obvious cardiac hypertrophy and fibrosis, increased O(2)*(-) production and NAD(P)H oxidase activity and expression in aorta and heart. The heart in 2K2C hypertensive rats preferred to use NADH as substrate while the aorta used both NADH and NADPH. Valsartan treatment decreased BP, ameliorated cardiac hypertrophy and fibrosis, decreased O(2)*(-) production and NAD(P)H oxidase activity in aorta and heart. Nox2 and Nox4 protein expression increased in heart, while Nox1 and Nox4 increased in aorta in 2K2C hypertensive rats, which were all normalized after valsartan treatment. In conclusion, these data indicate that different Nox expression might account for substrate preference and the formation of O(2)*(-) by NAD(P)H oxidase resulting from elevated Ang II in the 2K2C model contributes to the development of renovascular hypertension and subsequent cardiac remodeling.

Magnesium sulfate effectively reduces blood pressure in an animal model of preeclampsia

OBJECTIVE

We tested the ability of magnesium sulfate to reduce hypertension and neonatal growth retardation in an animal model of preeclampsia.

STUDY DESIGN

On day 17 of pregnancy, osmotic minipumps were inserted subcutaneously to continuously deliver either vehicle (saline control group), or N-nitro-L-arginine methyl ester (L-NAME) (50 mg/kg/day), or L-NAME (50 mg/kg/day) in combination with magnesium sulfate (60 mg/kg/day). Prior to insertion, blood pressure and heart rate were monitored with a pneumatic tail cuff device. Blood pressure measurements were repeated on days 18, 20, and 21 of pregnancy. Blood was obtained on days 17 and 21, along with urine, to assess magnesium levels and degree of proteinuria. Pups were weighed and measured at 48 hours postpartum.

RESULTS

Rats receiving L-NAME developed hypertension within 24 hours of implantation (108 +/- 3.9 vs. 123 +/- 3.4 mmHg, p < 0.05). Magnesium sulfate, given along with L-NAME did not prevent mean blood pressure from increasing, but reduced it by day 21 compared to L-NAME given alone (107 +/- 3.4 vs. 122 +/- 8.7 mmHg, respectively, p < 0.05). Magnesium sulfate reduced neonatal growth retardation by improving the weight of the pups compared to pups from maternal rats given L-NAME alone (6.1 +/- 0.1 vs. 5.2 +/- 0.3 grams, respectively, p < 0.05).

CONCLUSION

Maternal magnesium sulfate reduces blood pressure and increases neonatal size compared to L-NAME without magnesium. These findings support a beneficial effect of magnesium in preeclampsia.

Calcium signaling phenomena in heart diseases: a perspective

Ca(2+) is a major intracellular messenger and nature has evolved multiple mechanisms to regulate free intracellular (Ca(2+))(i) level in situ. The Ca(2+) signal inducing contraction in cardiac muscle originates from two sources. Ca(2+) enters the cell through voltage dependent Ca(2+) channels. This Ca(2+) binds to and activates Ca(2+) release channels (ryanodine receptors) of the sarcoplasmic reticulum (SR) through a Ca(2+) induced Ca(2+) release (CICR) process. Entry of Ca(2+) with each contraction requires an equal amount of Ca(2+) extrusion within a single heartbeat to maintain Ca(2+) homeostasis and to ensure relaxation. Cardiac Ca(2+) extrusion mechanisms are mainly contributed by Na(+)/Ca(2+) exchanger and ATP dependent Ca(2+) pump (Ca(2+)-ATPase). These transport systems are important determinants of (Ca(2+))(i) level and cardiac contractility. Altered intracellular Ca(2+) handling importantly contributes to impaired contractility in heart failure. Chronic hyperactivity of the beta-adrenergic signaling pathway results in PKA-hyperphosphorylation of the cardiac RyR/intracellular Ca(2+) release channels. Numerous signaling molecules have been implicated in the development of hypertrophy and failure, including the beta-adrenergic receptor, protein kinase C, Gq, and the down stream effectors such as mitogen activated protein kinases pathways, and the Ca(2+) regulated phosphatase calcineurin. A number of signaling pathways have now been identified that may be key regulators of changes in myocardial structure and function in response to mutations in structural components of the cardiomyocytes. Myocardial structure and signal transduction are now merging into a common field of research that will lead to a more complete understanding of the molecular mechanisms that underlie heart diseases. Recent progress in molecular cardiology makes it possible to envision a new therapeutic approach to heart failure (HF), targeting key molecules involved in intracellular Ca(2+) handling such as RyR, SERCA2a, and PLN. Controlling these molecular functions by different agents have been found to be beneficial in some experimental conditions.

Treatment of essential hypertension and non-insulin dependent diabetes mellitus with vitamin C

Inappropriate response of the carotid body region to encroachment of its perfusion results in essential hypertension (EH) and/or non-insulin dependent diabetes mellitus (NIDDM). This encroachment is caused by atherosclerosis. The carotid body perceives the encroachment on the lumen as a reduction in the availability of oxygen and glucose for the brain. Raising the perfusion pressure (thus, resulting in EH) and/ or inducing insulin resistance (causing NIDDM) are seen as compensatory mechanisms in response to the primary pathology, ie the encroachment of the lumen by atherosclerosis. Therefore, the reduction or reversal of the atherosclerosis process will help improve perfusion to the carotid bodies, which will in turn reduce or reverse the pathophysiological compensatory adjustments described above. A supplemental therapy, in addition to the standard treatment, with vitamin C is suggested here. The argument in favour of this suggestion is the basis of this paper. Vitamin C is a very important antioxidant. It is suggested to be used without any interference with the usual therapy prescribed for these two chronic diseases. It is recommended to be administered in small, frequent doses of 100mg every 2h, except during sleep. There is no need for compensation for the occasional missed dose. The safety of larger doses of vitamin C than the current recommendations, represents the beauty and is reassuring in recommending this approach.

Dysfunction of paracellin-1 by dephosphorylation in Dahl salt-sensitive hypertensive rats

A high-salt diet reduced the levels of renal cAMP content and serine-phosphorylated paracellin-1 in Dahl salt-sensitive hypertensive rats. In MDCK cells expressing paracellin-1, protein kinase A inhibitor reduced the serine-phosphorylated paracellin-1 and transepithelial Mg(2+) transport, suggesting that a dephosphorylation of paracellin-1 induces the reduction of Mg(2+) reabsorption in salt-sensitive hypertension.

Long-term moderate magnesium-deficient diet shows relationships between blood pressure, inflammation and oxidant stress defense in aging rats

Epidemiological and experimental studies have indicated a relationship among aging, dietary Mg, inflammatory stress, and cardiovascular disease. Our aim in the present study was to investigate possible links between dietary Mg, oxidant stress parameters, and inflammatory status with aging in rats. We designed a long-term study in which rats were fed for 22 months with moderately deficient (150 mg/kg), standard (800 mg/kg), or supplemented (3200 mg/kg) Mg diets. Comparisons were made with young rats fed with the same diets for 1 month. Compared to the standard and supplemented diets, the Mg-deficient diet significantly increased blood pressure, plasma interleukin-6, fibrinogen, and erythrocyte lysophosphatidylcholine, particularly in aging rats, it decreased plasma albumin. The impairment of redox status was indicated by increases in plasma thiobarbituric acid reactive substances and oxysterols and an increased blood susceptibility to in vitro free-radical-induced hemolysis. We concluded that Mg deficiency induced a chronic impairment of redox status associated with inflammation which could significantly contribute to increased oxidized lipids and promote hypertension and vascular disorders with aging. Extrapolating to the human situation and given that Mg deficiency has been reported to be surprisingly common, particularly in the elderly, Mg supplementation might be useful as an adjuvant therapy in preventing cardiovascular disease.

The effect of β-bungarotoxin, or geniculate ganglion lesion on taste bud development in the chick embryo

Chick taste bud (gemmal) primordia normally appear on embryonic day (E) 16 and incipient immature, spherical-shaped buds at E17. In ovo injection of beta-bungarotoxin at E12 resulted in a complete absence of taste buds in lower beak and palatal epithelium at developmental ages E17 and E21. However, putative gemmal primordia (solitary clear cells; small, cell groupings) remained, lying adjacent to salivary gland duct openings as seen in normal chick gemmal development. Oral epithelium was immunonegative to neural cell adhesion molecule (NCAM) suggesting gemmal primordia are nerve-independent. Some NCAM immunoreactivity was evident in autonomic ganglion-like cells and nerve fibers in connective tissue. After unilateral geniculate ganglion/otocyst excision on E2.5, at developmental ages E18 and posthatching day 1, approximately 12% of surviving ipsilateral geniculate ganglion cells sustained approximately 54% of the unoperated gemmal counts. After E18, proportional stages of differentiation in surviving developing buds probably reflect their degree of innervation, as well as rate of differentiation. Irrespective of the degree of geniculate ganglion damage, the proportion of surviving buds can be sustained at the same differentiated bud stage as on the unoperated side, or may differentiate to a later bud stage, consistent with the thesis that bud maturation, maintenance, and survival are nerve-dependent.

Role of magnesium in hypertension

Magnesium affects blood pressure by modulating vascular tone and reactivity. It acts as a calcium channel antagonist, it stimulates production of vasodilator prostacyclins and nitric oxide and it alters vascular responses to vasoactive agonists. Magnesium deficiency has been implicated in the pathogenesis of hypertension with epidemiological and experimental studies demonstrating an inverse correlation between blood pressure and serum magnesium levels. Magnesium also influences glucose and insulin homeostasis, and hypomagnesemia is associated with metabolic syndrome. Although most epidemiological and experimental studies support a role for low magnesium in the pathophysiology of hypertension, data from clinical studies have been less convincing. Furthermore, the therapeutic value of magnesium in the management of hypertension is unclear. The present review addresses the role of magnesium in the regulation of vascular function and blood pressure and discusses the implications of magnesium deficiency in experimental and clinical hypertension, in metabolic syndrome and in pre-eclampsia.

Oral administration of S-nitroso-N-acetylcysteine prevents the onset of non alcoholic fatty liver disease in rats

AIM

To evaluate the potential of S-nitroso-N-acetylcysteine (SNAC) in inhibition of lipid peroxidation and the effect of oral SNAC administration in the prevention of nonalcoholic fatty liver disease (NAFLD) in an animal model.

METHODS

NAFLD was induced in Wistar male rats by choline-deficient diet for 4 wk. SNAC-treated animals (n=6) (1.4 mg/kg per day of SNAC, orally) were compared to 2 control groups: one (n=6) received PBS solution and the other (n=6) received NAC solution (7 mg/kg per day). Histological variables were semiquantitated with respect to macro and microvacuolar fat changes, its zonal distribution, foci of necrosis, portal and perivenular fibrosis, and inflammatory infiltrate with zonal distribution. LOOHs from samples of liver homogenates were quantified by HPLC. Nitrate levels in plasma of portal vein were assessed by chemiluminescence. Aqueous low-density lipoprotein (LDL) suspensions (200 microg protein/mL) were incubated with CuCl(2) (300 micromol/L) in the absence and presence of SNAC (300 micromol/L) for 15 h at 37 degree Celsius. Extent of LDL oxidation was assessed by fluorimetry. Linoleic acid (LA) (18.8 micromol/L) oxidation was induced by soybean lipoxygenase (SLO) (0.056 micromol/L) at 37 degree Celsius in the presence and absence of N-acetylcysteine (NAC) and SNAC (56 and 560 micromol/L) and monitored at 234 nm.

RESULTS

Animals in the control group developed moderate macro and microvesicular fatty changes in periportal area. SNAC-treated animals displayed only discrete histological alterations with absence of fatty changes and did not develop liver steatosis. The absence of NAFLD in the SNAC-treated group was positively correlated with a decrease in the concentration of LOOH in liver homogenate, compared to the control group (0.7+/-0.2 nmol/mg vs 3.2+/-0.4 nmol/mg protein, respectively, P<0.05), while serum levels of aminotransferases were unaltered. The ability of SNAC in preventing lipid peroxidation was confirmed in in vitro experiments using LA and LDL as model substrates.

CONCLUSION

Oral administration of SNAC prevents the onset of NAFLD in Wistar rats fed with choline-deficient diet. This effect is correlated with the ability of SNAC to block the propagation of lipid peroxidation in vitro and in vitro.

Calcium paradox of aldosteronism and the role of the parathyroid glands

The hypercalciuria and hypermagnesuria that accompany aldosteronism contribute to a fall in plasma ionized extracellular Ca2+ and Mg2+ concentrations ([Ca2+]o and [Mg2+]o). Despite these losses and the decline in extracellular levels of these cations, total intracellular and cytosolic free Ca2+ concentration ([Ca2+]i) is increased and oxidative stress is induced. This involves diverse tissues, including peripheral blood mononuclear cells (PBMC) and plasma. The accompanying elevation in plasma parathyroid hormone (PTH) and reduction in bone mineral density caused by aldosterone (Aldo)-1% NaCl treatment (AldoST) led us to hypothesize that Ca2+ loading and altered redox state are due to secondary hyperparathyroidism (SHPT). Therefore, we studied the effects of total parathyroidectomy (PTx). In rats receiving AldoST, without or with a Ca2+-supplemented diet and/or PTx, we monitored urinary Ca2+ and Mg2+ excretion; plasma [Ca2+]o, [Mg2+]o, and PTH; PBMC [Ca2+]i and H2O2 production; plasma α1-antiproteinase activity; total Ca2+ and Mg2+ in bone, myocardium, and rectus femoris; and gp91phox labeling in the heart. We found that 1) the hypercalciuria and hypermagnesuria and decline ( P < 0.05) in plasma [Ca2+]o and [Mg2+]o that occur with AldoST were not altered by the Ca2+-supplemented diet alone or with PTx; 2) the rise ( P < 0.05) in plasma PTH with AldoST, with or without the Ca2+-supplemented diet, was prevented by PTx; 3) increased ( P < 0.05) PBMC [Ca2+]i and H2O2 production, increased total Ca2+ in heart and skeletal muscle, and fall in bone Ca2+ and Mg2+ and plasma α1-antiproteinase activity with AldoST were abrogated ( P < 0.05) by PTx; and 4) gp91phox activation in right and left ventricles at 4 wk of AldoST was attenuated by PTx. AldoST is accompanied by SHPT, with parathyroid gland-derived calcitropic hormones being responsible for Ca2+ overload in diverse tissues and induction of oxidative stress. SHPT plays a permissive role in the proinflammatory vascular phenotype.

Role of anion gap and different electrolytes in hypertension during pregnancy (preeclampsia)

The present study was designed to determine the changes in serum sodium, anion gap, different antioxidants and free radicals in preeclamptic patients and control subjects. Serum sodium, chloride, bicarbonate, calcium, potassium and magnesium were estimated and anion gap was determined in 100 proteinuric hypertensive and 100 normotensive pregnant women. Mean serum sodium, chloride and bicarbonate level (133.26 +/- 13.1, 104.97 +/- 11.37, and 22.01 +/- 4.66 mEq/l, respectively) were significantly higher in proteinuric hypertensive women as compared to controls (125.85 +/- 10.4, 101.90 +/- 6.3, 19.34 +/- 3.21 mEq/l, respectively) whereas anion gap level (6.28 +/- 16.147) was nonsignificantly higher in proteinuric hypertensive as compared to normotensive (4.61 +/- 11.84). Total serum sodium concentration increases in preeclamptic subjects, the exact distribution of serum sodium in various compartments of the body are not clear and correlation of serum sodium and anion gap with proteinuria is also not known. The levels of different antioxidants were decreased in preeclamptic patients as compared to the controls while the level of free radicals elevated in preeclamptic subjects as compared to controls. In our study, anion gap level was found to be rather non-significantly higher in proteinuric hypertensive women as compared to normotensive women.

Different antioxidants status, total antioxidant power and free radicals in essential hypertension

Hypertension is a multi-factorial process, prevalent in developed as well as in developing countries. Different antioxidants and free radicals play an important role in cardiovascular system. In present study, total antioxidant power in terms of FRAP (ferric reducing activity of plasma), free radicals and different antioxidants have been studied in essential hypertensives (n = 50) and normal subjects (n = 50). Levels of total cholesterol, low-density lipids-cholesterol, malonialdehyde, very low-density lipids (VLDL), uric acid, plasma homocysteine and low-density lipids (LDL), were significantly higher in hypertensives as compared to normotensive. HDL-cholesterol, SOD, GPx, reduced glutahione, total glutathione, oxidized glutathione, total thiols, protein thiols, non protein thiols, RNI, total antioxidant power, vitamin A, ascorbic acid and glutahione-S-transferase (GST) were decreased significantly in normotensive. We observed significantly low nitric oxide levels in hypertensive patients. No correlation was observed between severity of disease and plasma nitric oxide levels. There was a significant decrease in plasma FRAP value in essential hypertensives as compared to normotensive controls, which showed a negative correlation with diastolic blood pressure. In conclusion, our study revealed that there was a consistent significant difference between essential hypertensives versus controls with respect to most of the parameters. These complex changes are consistent in the view that essential hypertension is associated with an abnormal level of antioxidant status compared to normal response to oxidative stress or both.

Aldosteronism and a Proinflammatory Vascular Phenotype

Background— Chronic, inappropriate (relative to dietary Na + ) elevations in circulating aldosterone, such as occur in congestive heart failure, are accompanied by a proinflammatory vascular phenotype involving the coronary and systemic vasculature. An immunostimulatory state with activated peripheral blood mononuclear cells (PBMCs) precedes this phenotype and is induced by a fall in cytosolic free [Mg 2+ ] i and subsequent Ca 2+ loading of these cells and transduced by oxidative/nitrosative stress.

Methods and Results— We sought to further validate this hypothesis in rats with aldosterone/1%NaCl treatment (ALDOST) by using several interventions as cotreatment: a Mg 2+ -supplemented diet; amlodipine, a CCB; and N -acetylcysteine, an antioxidant. Blood samples were obtained at weeks 1 to 4 of ALDOST to monitor [Mg 2+ ] i , [Ca 2+ ] I , and H 2 O 2 production in PBMCs. Coronal ventricular sections were examined for invading inflammatory cells and 3-nitrotyrosine labeling, a marker of oxidative/nitrosative stress. In response to ALDOST and compared with untreated controls, we found an early and persistent reduction in [Mg 2+ ] i with a subsequent rise in [Ca 2+ ] i and H 2 O 2 production, each of which was either attenuated or abrogated by the Mg 2+ -supplemented diet and by N -acetylcysteine, whereas amlodipine prevented Ca 2+ loading and an altered redox state. Cotreatment with these interventions either markedly attenuated or prevented the appearance of the proinflammatory coronary vascular phenotype and the presence of 3-nitrotyrosine in invading inflammatory cells.

Conclusions— We suggest that the immunostimulatory state that appears during aldosteronism and leads to a proinflammatory coronary vascular phenotype is induced by a fall in [Mg 2+ ] i with Ca 2+ loading of PBMCs and is transduced by H 2 O 2 production in these cells.

Pancreatic cancer

Pancreatic cancer remains a major unsolved health problem, with conventional cancer treatments having little impact on disease course. Almost all patients who have pancreatic cancer develop metastases and die. The main risk factors are smoking, age, and some genetic disorders, although the primary causes are poorly understood. Advances in molecular biology have, however, greatly improved understanding of the pathogenesis of pancreatic cancer. Many patients have mutations of the K-ras oncogene, and various tumour-suppressor genes are also inactivated. Growth factors also play an important part. However, disease prognosis is extremely poor. Around 15-20% of patients have resectable disease, but only around 20% of these survive to 5 years. For locally advanced, unresectable, and metastatic disease, treatment is palliative, although fluorouracil chemoradiation for locally advanced and gemcitabine chemotherapy for metastatic disease can provide palliative benefits. Despite pancreatic cancer's resistance to currently available treatments, new methods are being investigated. Preoperative chemoradiation is being advocated, with seemingly sound reasoning, and a wider role for gemcitabine is being explored. However, new therapeutic strategies based on the molecular biology of pancreatic cancer seem to hold the greatest promise.

Low [Mg 2+ ] e Enhances Arterial Spontaneous Tone via Phosphatidylinositol 3-Kinase in DOCA-Salt Hypertension

Phosphatidylinositol 3-kinase (PI3K) has been implicated in low extracellular Mg 2+ concentration ( [Mg 2+ ] e )–induced aortic contraction, and Mg 2+ deficiency has been associated with hypertension. Moreover, arterial PI3K activity is increased in hypertensive deoxycorticosterone (DOCA)-salt rats. We hypothesized that low [Mg 2+ ] e activates PI3K, eliciting enhanced vascular contraction, PI3K activity, and norepinephrine (NE)-induced contraction. Spontaneous tone was monitored in endothelium-denuded aortic strips from sham and DOCA-salt rats exposed to low Mg 2+ (0.15 mmol/L), high Mg 2+ (4.8 mmol/L), or normal (1.17 mmol/L) physiologic salt solution (PSS) in isolated tissue baths. LY294002 (20 μmol/L), a PI3K inhibitor, or vehicle was added (30 minutes), followed by NE (10 −9 to 3 x10 −-5 mol/L). Low [Mg 2+ ] e significantly enhanced tone in aortas from DOCA-salt and sham rats compared with normal PSS (DOCA-salt low [Mg 2+ ] e , +51.5 +7.0 vs DOCA-salt normal PSS, +7.1 +1.4 % of initial phenylephrine [PE] contraction). LY294002 and incubation with high Mg 2+ PSS decreased tone in aortas from DOCA-salt rats (low [Mg 2+ ] e LY294002, −-87.5 +8.8; normal PSS LY294002, −81.7 +13.7; and high [Mg 2+ ] e , −31.2 +10.8 % of initial PE contraction). Low [Mg 2+ ] e leftward-shifted NE-induced aortic contractions in sham and thus matched the shift observed with DOCA (−log EC 50 mol/L: sham PSS, −7.7 +0.1; DOCA-salt PSS, −8.2 +0.1; sham low [Mg 2+ ] e , −8.2 +0.1; and DOCA-salt low [Mg 2+ ] e , −8.1 +0.1). Moreover, this shift was inhibited by LY294002. In conclusion, low [Mg 2+ ] e might activate PI3K, leading to enhanced tone and agonist-induced contraction observed in aortas from DOCA-salt hypertensive rats.

Aldosteronism and peripheral blood mononuclear cell activation: a neuroendocrine-immune interface

Aldosteronism eventuates in a proinflammatory/fibrogenic vascular phenotype of the heart and systemic organs. It remains uncertain whether peripheral blood mononuclear cells (PBMCs) are activated before tissue invasion by monocytes/macrophages and lymphocytes, as is the case for responsible pathogenic mechanisms. Uninephrectomized rats treated for 4 weeks with dietary 1% NaCl and aldosterone (ALDOST, 0.75 microg/h) with or without spironolactone (Spi, 100 mg/kg per daily gavage) were compared with unoperated/untreated and uninephrectomized/salt-treated controls. Before intramural coronary vascular lesions appeared at week 4 of ALDOST, we found (1) a reduction of PBMC cytosolic free [Mg2+]i, together with intracellular Mg2+ and Ca2+ loading, whereas plasma and cardiac tissue Mg2+ were no different from controls; (2) increased H2O2 production by monocytes and lymphocytes together with upregulated PBMC gene expression of oxidative stress-inducible tyrosine phosphatase and Mn2+-superoxide dismutase and the presence of 3-nitrotyrosine in CD4+ and ED-1-positive inflammatory cells that had invaded intramural coronary arteries; (3) B-cell activation, including transcription of immunoglobulins, intracellular adhesion molecule-1, and CC and CXC chemokines and their receptors; (4) expansion of B lymphocyte subset and myosin heavy chain class II-expressing lymphocytes; and (5) autoreactivity with gene expression for antibodies to acetylcholine receptors and a downregulation of RT-6.2, which is in keeping with cell activation and associated with autoimmunity. Spi cotreatment attenuated the rise in intracellular Ca2+, the appearance of oxidative/nitrosative stress in PBMCs and invading inflammatory cells, and alterations in PBMC transcriptome. Thus, aldosteronism is associated with an activation of circulating immune cells induced by iterations in PBMC divalent cations and transduced by oxidative/nitrosative stress. ALDO receptor antagonism modulates this neuroendocrine-immune interface. The full text of this article is available online at http://www.circresaha.org.