Global DNA methylation and hydroxymethylation differ in hepatocellular carcinoma and cholangiocarcinoma and relate to survival rate.

UNLABELLED: In addition to DNA methylation, hydroxymethylation of DNA is recognized as a novel epigenetic mark. Primary liver cancers, i.e., hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC), are highly prevalent but epigenetically poorly characterized, so far. In the present study we measured global methylcytosine (mCyt) and hydroxymethylcytosine (hmCyt) in HCC and CC tissues and in peripheral blood mononuclear cell (PBMC) DNA to define mCyt and hmCyt status and, accordingly, the survival rate. Both mCyt and hmCyt were measured by a liquid chromatography/tandem mass spectrometry method in neoplastic and homologous nonneoplastic tissues, i.e., liver and gallbladder, and in PBMCs of 31 HCC and 16 CC patients. Content of mCyt was notably lower in HCC than in CC tissues (3.97% versus 5.26%, respectively; P < 0.0001). Significantly reduced mCyt was also detected in HCC compared to nonneoplastic tissue (3.97% versus 4.82% mCyt, respectively; P < 0.0001), but no such difference was found for CC versus homologous nonneoplastic tissue. Hydroxymethylation was significantly decreased in HCC versus nonneoplastic liver tissue (0.044 versus 0.128, respectively; P < 0.0001) and in CC versus both liver and gallbladder nonneoplastic tissue (0.030 versus 0.124, P = 0.026, and 0.030 versus 0.123, P = 0.006, respectively). When the survival rate was evaluated according to mCyt PBMC content by Kaplan-Meier analysis, patients with mCyt ≥5.59% had a significantly higher life expectancy than those with mCyt <5.59% (P = 0.034) at a follow-up period up to 48 months. CONCLUSION: A significant DNA hypomethylation distinguishes HCC from CC, while DNA hypo-hydroxymethylation characterizes both HCC and CC, and a PBMC DNA mCyt content ≥5.59% relates to a favorable outcome in primary liver cancers.

Delta-5 and delta-6 desaturases: crucial enzymes in polyunsaturated fatty acid-related pathways with pleiotropic influences in health and disease.

Polyunsaturated fatty acids (PUFA) play pleiotropic and crucial roles in biological systems. Both blood and tissue levels of PUFA are influenced not only by diet, but to a large extent also by genetic heritability. Delta-5 (D5D) and delta-6 desaturases (D6D), encoded respectively by FADS1 and FADS2 genes, are the rate-limiting enzymes for PUFA conversion and are recognized as main determinants of PUFA levels. Alterations of D5D/D6D activity have been associated with several diseases, from metabolic derangements to neuropsychiatric illnesses, from type 2 diabetes to cardiovascular disease, from inflammation to tumorigenesis. Similar results have been found by investigations on FADS1/FADS2 genotypes. Recent genome-wide association studies showed that FADS1/FADS2 genetic locus, beyond being the main determinant of PUFA, was strongly associated with plasma lipids and glucose metabolism. Other analyses suggested potential link between FADS1/FADS2 polymorphisms and cognitive development, immunological illnesses, and cardiovascular disease. Lessons from both animal models and rare disorders in humans further emphasized the key role of desaturases in health and disease. Remarkably, some of the above mentioned associations appear to be influenced by the environmental context/PUFA dietary intake, in particular the relative prevalence of ω-3 and ω-6 PUFA. In this narrative review we provide a summary of the evidences linking FADS1/FADS2 gene variants and D5D/D6D activities with various traits of human physiopathology. Moreover, we focus also on the potentially useful therapeutic application of D5D/D6D activity modulation, as suggested by anti-inflammatory and tumor-suppressing effects of D6D inhibition in mice models.

Promoter methylation in coagulation F7 gene influences plasma FVII concentrations and relates to coronary artery disease.

BACKGROUND: Plasma factor VII concentrations (FVIIa), a marker of coronary artery disease (CAD) risk, are influenced by genetic markers at the promoter site: the A2 allele, due to a 10bp insertion at position -323, is a determinant of lower FVIIa concentrations and reduced CAD risk, while the -402A allele, due to a G>A substitution, confers increased transcriptional activity in vitro resulting in higher FVIIa. Transcriptional regulation of F7 by epigenetic features is, however, still unknown as is the inter-relationship of genetic and epigenetic modifications at the promoter site. OBJECTIVE: To investigate a possible epigenetic regulation of the F7 gene at the promoter region and its link with functional F7 polymorphisms at the same site. METHODS AND RESULTS: F7 promoter methylation and its relation to F7 promoter polymorphisms in modulating FVIIa and CAD risk were evaluated by methyl-specific PCR and bisulfite sequencing techniques in 253 subjects, of whom 168 had CAD and 88 were CAD-free. Plasma FVIIa was inversely related to methylation in A1A1 and -402GG, that is in the absence of the rare A2 and -402A allele. The higher FVIIa paralleled the lower methylation in A1A1 compared to A2A2 (p=0.035), while no variation in methylation was associated with the different -402G>A genotypes. The modulation of methylation-induced FVIIa concentrations was observed only in A1A1 where the higher methylation resulting in lower FVIIa was prevalent within the CAD-free group compared to the CAD group (p=0.011). CONCLUSIONS: Epigenetic regulation through methylation of F7 promoter is associated with CAD by affecting plasma FVIIa concentrations in A1A1 genotypes.

Folic acid effects on s-adenosylmethionine, s-adenosylhomocysteine, and DNA methylation in patients with intermediate hyperhomocysteinemia.

OBJECTIVE: Folic acid (FA) supplementation decreases homocysteine (tHcy) levels. However, little is known about the effects of FA treatment on DNA methylation or plasma S-adenosylmethionine (AdoMet) and S-adenosylhomocysteine (AdoHcy) concentrations. The purpose of this study was to investigate the effects of FA supplementation on AdoMet, AdoHcy, and genomic DNA methylation in hyperhomocysteinemic subjects without end-stage renal disease. METHODS: To evaluate the effects of 5 mg FA/d for 8 weeks, we recruited 7 hyperhomocysteinemic MTHFR677TT patients (tHcy >30 µmol/L) with normal renal function. RESULTS: FA supplementation induced a decrease in tHcy (from 51.1 ± 21 at baseline to 26.1 ± 27 µmol/L after folate supplementation; p < 0.01). A parallel increase was seen in plasma AdoMet concentrations and the AdoMet/AdoHcy ratio (p < 0.05). However, FA supplementation had no effect on global DNA methylation levels in the present study. CONCLUSIONS: Supraphysiologic FA supplementation can modulate biochemical markers in one-carbon metabolism such as tHcy, AdoMet, and the AdoMet/AdoHcy ratio in hyperhomocysteinemic subjects. However, the reduction in homocysteinemia and the increased availability of methyl compounds provided by vitamin supplementation may not be sufficient to affect genomic DNA methylation.

SNPs of the FADS gene cluster are associated with polyunsaturated fatty acids in a cohort of patients with cardiovascular disease.

Polymorphisms of the human Delta-5 (FADS1) and Delta-6 (FADS2) desaturase genes have been recently described to be associated with the level of several long-chain n-3 and n-6 polyunsaturated fatty acids (PUFAs) in serum phospholipids. We have genotyped 13 single nucleotide polymorphisms (SNPs) located on the FADS1-FADS2-FADS3 gene cluster (chromosome 11q12-13.1) in 658 Italian adults (78% males; mean age 59.7 +/- 11.1 years) participating in the Verona Heart Project. Polymorphisms and statistically inferred haplotypes showed a strong association with arachidonic acid (C20:4n-6) levels in serum phospholipids and in erythrocyte cell membranes (rs174545 adjusted P value for multiple tests, P < 0.0001 and P < 0.0001, respectively). Other significant associations were observed for linoleic (C18:2n-6), alpha-linolenic (C18:3n-3) and eicosadienoic (C20:2n-6) acids. Minor allele homozygotes and heterozygotes were associated to higher levels of linoleic, alpha-linolenic, eicosadienoic and lower levels of arachidonic acid. No significant association was observed for stearidonic (C18:4n-3), eicosapentaenoic (C20:5n-3) and docosahexaenoic (C22:6n-3) acids levels. The observed strong association of FADS gene polymorphisms with the levels of arachidonic acid, which is a precursor of molecules involved in inflammation and immunity processes, suggests that SNPs of the FADS1 and FADS2 gene region are worth studying in diseases related to inflammatory conditions or alterations in the concentration of PUFAs.

One-carbon genetic variants and the role of MTHFD1 1958G>A in liver and colon cancer risk according to global DNA methylation.

Several polymorphic gene variants within one-carbon metabolism, an essential pathway for nucleotide synthesis and methylation reactions, are related to cancer risk. An aberrant DNA methylation is a common feature in cancer but whether the link between one-carbon metabolism variants and cancer occurs through an altered DNA methylation is yet unclear. Aims of the study were to evaluate the frequency of one-carbon metabolism gene variants in hepatocellular-carcinoma, cholangiocarcinoma and colon cancer, and their relationship to cancer risk together with global DNA methylation status. Genotyping for BHMT 716A>G, DHFR 19bp ins/del, MTHFD1 1958G>A, MTHFR 677C>T, MTR 2756A>G, MTRR 66A>G, RFC1 80G>A, SHMT1 1420C>T, TCII 776C>G and TS 2rpt-3rpt was performed in 102 cancer patients and 363 cancer-free subjects. Methylcytosine (mCyt) content was measured by LC/MS/MS in peripheral blood mononuclear cells (PBMCs) DNA. The MTHFD1 1958AA genotype was significantly less frequent among cancer patients as compared to controls (p = 0.007) and related to 63% reduction of overall cancer risk (p = 0.003) and 75% of colon cancer risk (p = 0.006). When considering PBMCs mCyt content, carriers of the MTHFD1 1958GG genotype showed a lower DNA methylation as compared to carriers of the A allele (p = 0.048). No differences were highlighted by evaluating a possible relationship between the other polymorphisms analyzed with cancer risk and DNA methylation. The MTHFD1 1958AA genotype is linked to a significantly reduced cancer risk. The 1958GG genotype is associated to PBMCs DNA hypomethylation as compared to the A allele carriership that may exert a protective effect for cancer risk by preserving from DNA hypomethylation.

Can 5-methyltetrahydrofolate modify the phospholipid fatty acid pattern in cystic fibrosis pediatric patients?

Recent studies have reported an imbalance between n6 and n3 fatty acids (AA and DHA) in subjects with CF. Alterations in fatty acid amounts are present in CFTR-expressing tissues, plasma and in circulating blood cells. It has been reported that the correction of polyunsaturated fatty acid deficiency reversed the organ pathologies observed in CF knockout mice. We describe a CF child with an unusual clinical course presenting high molar percentage of DHA in plasma and red cells membrane during supplementation with 5-methyltetrahydrofolate and vitamin B12.

The RFC1 80G>A, among Common One-Carbon Polymorphisms, Relates to Survival Rate According to DNA Global Methylation in Primary Liver Cancers.

Polymorphisms within one-carbon metabolism genes have been largely studied in relation to cancer risk for the function of this pathway in nucleotide synthesis and DNA methylation. Aims of this study were to explore the possible link among several common functional gene polymorphisms within one-carbon metabolism and survival rate in primary liver cancers, i.e., hepatocellular carcinoma and cholangiocarcinoma, and to assess the additional effect of global DNA methylation on survival rate and mortality risk. Forty-seven primary liver cancer patients were genotyped for ten polymorphisms: DHFR 19bp ins/del, TS 2rpt-3rpt, MTHFD1 1958G>A, MTHFR 677C>T, MTR 2756A>G, MTRR 66A>G, RFC1 80G>A, SHMT1 1420C>T, BHMT 716 A>G, TC II 776C>G. Methylation was determined in peripheral blood mononuclear cells (PBMCs) DNA as methylcytosine (mCyt) content using LC/MS/MS. Among the polymorphisms analysed, the RFC1 80G>A (rs1051266) influenced the survival rate in primary liver cancers. The RFC1 80AA was associated to a significantly reduced survival rate (22.2%) as compared to both GG and GA genotypes (61.5% and 76% respectively, p = 0.005). When the cancer patients were stratified according to the mCyt median value as high (>5.34%) or low (≤5.34%), the concomitant presence of AA genotype and low mCyt level led to a significantly worse survival rate as compared to the G allele carriership (p<0.0001) with a higher Hazard Ratio (HR = 6.62, p = 0.001). The subjects carrying the AA genotype in association with high mCyt did not show a significant difference in survival rate as compared with the G allele carriers (p = 0.919). The RFC1 80G>A polymorphism influenced the survival rate, and the presence of RFC1 80AA genotype with low global methylation in PBMCs DNA was associated with poorer prognosis and higher mortality risk, therefore highlighting novel molecular signatures potentially helpful to define prognostic markers for primary liver cancers.

The MTHFR 1298A>C polymorphism and genomic DNA methylation in human lymphocytes.

Methylenetetrahydrofolate reductase (MTHFR) balances the pool of folate coenzymes in one-carbon metabolism for DNA synthesis and methylation, both implicated in carcinogenesis. Epidemiologic studies have shown that two functional polymorphisms in MTHFR gene, 677C>T and 1298A>C, are related to increased cancer risk. We aimed to analyze lymphocyte DNA from 198 subjects to evaluate the MTHFR 1298A>C polymorphism and folate status affecting genomic DNA methylation as a possible mechanism underlying the relationship between MTHFR polymorphisms and cancer susceptibility. Carriers of the 1298AA wild-type genotype showed lower genomic DNA methylation compared with 1298AC or 1298CC genotypes [3.72 versus 8.59 or 6.79 ng 5-methyl-2'-deoxycytidine (5-mCyt)/microg DNA, P < 0.0001 and P = 0.007, respectively]. When DNA methylation was evaluated according to plasma folate status, only 1298AA with low folate levels revealed diminished DNA methylation (P < 0.0001). Moreover, when the two MTHFR polymorphisms were concomitantly evaluated at the low folate status, DNA methylation was reduced only in 1298AA/677TT compared with 1298AA/677CC (3.11 versus 7.29 ng 5-mCyt/microg DNA, P = 0.001) and 1298CC/677CC genotypes (3.11 versus 7.14 ng 5-mCyt/microg DNA, P = 0.004). However, the high prevalence of 677TT mutants within the 1298AA group (79%) and the similar biochemical features of 1298AA/677CC and 1298CC/677CC combined genotypes suggest that the gene-nutrient interaction affecting DNA methylation in 1298AA is mainly due to the coexistence of the 677TT genotype and that the 1298A>C polymorphism may convey its protective effect not through this interaction but through another pathway in one-carbon metabolism. Further mechanistic studies are warranted to investigate how single polymorphisms as well as MTHFR combined genotypes exert their effect on cancer susceptibility.

Primary hyperaldosteronism: a frequent cause of residual hypertension after successful endovascular treatment of renal artery disease.

BACKGROUND: Poor blood pressure control in renal artery disease patients after percutaneous renal angioplasty (PTRA), with or without stenting (PTRAS), may be due to pre-existing hypertension. Primary hyperaldosteronism is much more frequent than was previously suspected. We hypothesized that residual hypertension observed in some renal artery disease patients after technically successful endovascular treatment may be due to primary hyperaldosteronism. METHODS: Only patients free of significant residual artery stenosis were included in the study. Aldosterone and renin were measured in 52 renal artery disease patients (8 with fibrodysplastic and 44 with atherosclerotic lesions), in whom successful PTRA/PTRAS had been performed previously. An aldosterone-to-renin ratio > or = 23 pg/ml per pg/ml was considered as the cut-off value for performing tests to confirm the diagnosis of primary hyperaldosteronism. RESULTS: Residual hypertension (blood pressure > or = 160/90 mmHg) was observed in 24/52 patients (46%) after revascularization. A raised aldosterone-to-renin ratio was found in nine subjects (17.3%), eight of whom had poor blood pressure control (33% of patients with residual hypertension). A diagnosis of primary hyperaldosteronism was confirmed in seven patients (four atherosclerotic, three fibrodysplastic). All fibrodysplastic subjects with unresponsive blood pressure after PTRA were affected by primary hyperaldosteronism. Primary hyperaldosteronism was confirmed in 9% (4/44) of the atherosclerotic patients (19% of subjects with residual hypertension). No specific clinical features were associated with the subsequent blood pressure control. CONCLUSIONS: Primary hyperaldosteronism is a frequently neglected cause of residual hypertension despite technically successful endovascular treatment of renal artery disease.

Circadian exosomal expression of renal thiazide-sensitive NaCl cotransporter (NCC) and prostasin in healthy individuals.

PURPOSE: A circadian timing system is involved in the maintenance of fluid and electrolyte balance and blood pressure control. Aldosterone and vasopressin modulate ion transporters and channels crucial in sodium (Na) and water reabsorption such as the epithelium Na channel and the renal thiazide-sensitive NaCl cotransporter (NCC). We analyzed in urinary exosomes the intraday variations of NCC and prostasin expression and the association with electrolytes and water balance parameters. EXPERIMENTAL DESIGN: Blood and urine samples were collected at five time points during the day from five healthy subjects. Blood renin, aldosterone, cortisol, ACTH, and plasmatic and urinary Na, potassium, creatinine, adiuretin (ADH), NCC, and prostasin were evaluated. RESULTS: ACTH and cortisol showed a circadian pattern, similarly to aldosterone, while exosomal NCC and prostasin pattern were similar to urinary ADH, decreased in the morning and subsequently increased in the afternoon and evening. CONCLUSIONS AND CLINICAL RELEVANCE: In urinary exosomes, NCC and prostasin had a diurnal pattern parallel to ADH and aquaporin 2, confirming that, in healthy subjects, both prostasin and NCC relate to water balance. These results provide suggestions for a possible chronotherapeutic approach in patients treated with thiazides, diuretic drugs acting as specific inhibitors of NCC-mediated Na reabsorption.

DNA methylation and gene expression profiles show novel regulatory pathways in hepatocellular carcinoma.

BACKGROUND: Alcohol is a well-known risk factor for hepatocellular carcinoma (HCC), but the mechanisms underlying the alcohol-related hepatocarcinogenesis are still poorly understood. Alcohol alters the provision of methyl groups within the hepatic one-carbon metabolism, possibly inducing aberrant DNA methylation. Whether specific pathways are epigenetically regulated in alcohol-associated HCC is, however, unknown. The aim of the present study was to investigate the genome-wide promoter DNA methylation and gene expression profiles in non-viral, alcohol-associated HCC. From eight HCC patients undergoing curative surgery, array-based DNA methylation and gene expression data of all annotated genes were analyzed by comparing HCC tissue and homologous cancer-free liver tissue. RESULTS: After merging the DNA methylation with gene expression data, we identified 159 hypermethylated-repressed, 30 hypomethylated-induced, 49 hypermethylated-induced, and 56 hypomethylated-repressed genes. Notably, promoter DNA methylation emerged as a novel regulatory mechanism for the transcriptional repression of genes controlling the retinol metabolism (ADH1A, ADH1B, ADH6, CYP3A43, CYP4A22, RDH16), iron homeostasis (HAMP), one-carbon metabolism (SHMT1), and genes with a putative, newly identified function as tumor suppressors (FAM107A, IGFALS, MT1G, MT1H, RNF180). CONCLUSIONS: A genome-wide DNA methylation approach merged with array-based gene expression profiles allowed identifying a number of novel, epigenetically regulated candidate tumor-suppressor genes in alcohol-associated hepatocarcinogenesis. Retinol metabolism genes and SHMT1 are also epigenetically regulated through promoter DNA methylation in alcohol-associated HCC. Due to the reversibility of epigenetic mechanisms by environmental/nutritional factors, these findings may open up to novel interventional strategies for hepatocarcinogenesis prevention in HCC related to alcohol, a modifiable dietary component.

The local complement activation on vascular bed of patients with systemic sclerosis: a hypothesis-generating study.

OBJECTIVE: The role of complement system in the pathogenesis of systemic sclerosis (SSc) has been debated during the last decade but an evident implication in this disease has never been found. We carried out an explorative study on SSc patients to evaluate the expression of soluble and local C5b-9 complement complex and its relation with a complement regulator, the Membrane Cofactor Protein (MCP, CD46) on skin vascular bed as target distinctive of SSc disease. We also analyzed two polymorphic variants in the complement activation gene cluster involving the MCP region. METHODS: C5b-9 plasma levels of SSc patients and healthy subjects were analyzed by ELISA assay. Archival skin biopsies of SSc patients and controls were subjected to immunofluorescence analysis to detect C5b-9 and MCP on vascular endothelial cells. The expression of MCP was validated by immunoblot analysis with specific antibody. Polymorphic variants in the MCP gene promoter were tested by a quantitative PCR technique-based allelic discrimination method. RESULTS: Even though circulating levels of C5b-9 did not differ between SSc and controls, C5b-9 deposition was detected in skin biopsies of SSc patients but not in healthy subjects. MCP was significantly lower in skin vessels of SSc patients than in healthy controls and was associated with the over-expression of two polymorphic variants in the MCP gene promoter, which has been related to more aggressive phenotypes in other immune-mediated diseases. CONCLUSIONS: Our results firsty document the local complement activation with an abnormal expression of MCP in skin vessels of SSc patients, suggesting that a subset of SSc patients might be exposed to more severe organ complications and clinical evolution due to abnormal local complement activation.

Aldosterone to Renin ratio in a primary care setting: the Bussolengo study.

The aim of the study was to evaluate the prevalence of hypertension associated with an elevated aldosterone to renin activity ratio (ARR) in a sample of adults aged 35-74 yr, randomly selected from the population register of the Bussolengo Health District (northern Italy) and representative of the total population of the district. Subjects (n = 1462) were randomly selected from the population register and examined by their general practitioners. Complete data for 1348 individuals were available for final statistical analysis. Apart from verapamil or alpha-blockers, no hypotensive drugs were allowed during the 4 wk before assay. Direct active renin and aldosterone were measured in the plasma of hypertensive patients after 2 h in the upright posture. Of 412 identified hypertensive patients, 287 subjects agreed to give blood (70% response rate). An aldosterone to active renin ratio (AARR) of 32 pg/ml was taken as the cut-off value, equivalent to an ARR of 50 ng/dl/ng/ml.h. An elevated AARR was observed in 32.4% of the hypertensive patients, with increased prevalence in females and in people aged 55 yr or older. As an elevated AARR is frequent in the general hypertensive population, screening should not be limited to the patients referred to specialist units.

NT-proBNP, a useful tool in hypertensive patients undergoing a diagnostic evaluation for primary aldosteronism.

Primary aldosteronism (PA) is the most frequent form of secondary hypertension, but diagnostic tools for this disease still lack optimal accuracy. The heart is one important target tissue for damage due to excess aldosterone, and the role of natriuretic peptides is well recognized in diagnosing heart failure. We hypothesized that measuring the NT-proBNP could improve the diagnostic evaluation of PA. We enrolled 132 hypertensive patients, who underwent aldosterone to renin ratio (ARR) screening, and 81 underwent an intravenous saline loading test (ivSLT) because of a high ARR. The NT-proBNP level positively correlated with the ARR and inversely correlated with the renin level. The NT-proBNP level was higher in patients with a high ARR than in those with a low ARR and higher in patients with a positive ivSLT than in those with a negative ivSLT. After logistic regression analysis, an NT-proBNP value above the median and male gender were predictors of a positive ivSLT. The proportion of patients with a positive ivSLT ranged from only 23 % in females with a low NT-proBNP to 93 % in males with a high NT-proBNP. NT-proBNP and gender are predictors of a positive PA confirmatory test. These findings highlight the possibility of using NT-proBNP to identify which patients with a high ARR should receive a complete PA diagnostic evaluation.

Urinary protease inhibitor Serpin B3 is higher in women and is further increased in female patients affected by aldosterone producing adenoma.

A correct diagnosis of primary aldosteronism (PA) requires adrenal venous sampling (AVS) for the classification of subtypes (bilateral hyperplasia, BAH, or adenoma, APA). Since such testing is not easily practicable, appropriate markers for the definition of subtypes are desirable. We hypothesized that an aldosterone excess was associated with abnormalities in urinary proteome, specific for PA subtypes. The project work was divided into 3 phases: (1) screening/identification by proteomic analysis and further characterization by RT-PCR and immunohistochemistry of the candidate protein; (2) clinical validation by quantitative ELISA assay of 57 (33 M, 24 F) PA patients and 50 normotensive controls (21 M, 29 F); (3) analysis of adrenal tissue of 8 individuals who had undergone adrenalectomy for APA or other adrenal tumors. The proteomic analysis showed a different expression of Serpin B3 Inhibitor-SCCA1 (SB3) in APA and BAH patients. Urine SB3 concentrations in normotensive controls, quantified by ELISA assay and normalized by urinary creatinine, resulted much lower in males (6.72 ng SB3 per mg creatinine, C.I. 4.43-10.19) than in females (20.56 ng SB3 per mg creatinine, C.I. 12.43-33.99, p < 0.00001). SB3 concentrations were not significantly different in males affected by different PA subtypes (BAH, n = 19 and APA, n = 14) compared with normotensive subjects (n = 21). In contrast, in PA females, SB3 was significantly higher in APA (n = 13) than in BAH patients (n = 11) or in normotensive controls (n = 29) (P < 0.01 and <0.05, respectively). Neither messenger RNA nor SB3 protein were identified in tissue obtained from adrenal tumors and from the surrounding normal gland. In conclusion urine SB3 concentrations are physiologically much lower in males than in females. Hypertensive women, affected by APA, present urinary SB3 concentrations significantly higher than women affected by BAH.

Cardiovascular epigenetics: from DNA methylation to microRNAs.

Epigenetic phenomena are defined as heritable mechanisms that establish and maintain mitotically stable patterns of gene expression without modifying the base sequence of DNA. The major epigenetic features of mammalian cells include DNA methylation, post-translational histone modifications and RNA-based mechanisms including those controlled by small non-coding RNAs (miRNAs). The impact of epigenetic mechanisms in cardiovascular pathophysiology is now emerging as a major player in the interface between genotype to phenotype variability. This topic of research has strict implications on disease development and progression, and opens up possible novel preventive strategies in cardiovascular disease. An important aspect of epigenetic mechanisms is that they are potentially reversible and may be influenced by nutritional-environmental factors and through gene-environment interactions, all of which have an important role in complex, multifactorial diseases such as those affecting the cardiovascular system. Gene expression regulation through the interplay of DNA methylation and histone modifications is well-established, although the knowledge about the function of epigenetic signatures in cardiovascular disease is still largely unexplored. The study of epigenetic markers is, therefore, a very promising frontier of science which may aid in a deeper understanding of molecular mechanisms underlying the modulation of gene expression in the biomolecule pathways linked to cardiovascular diseases. This review focuses on up-to-date knowledge pertaining to the role of epigenetics, from DNA methylation to miRNAs, in major cardiovascular diseases such as ischemic heart disease, hypertension, heart failure and stroke.

Urinary prostasin in normotensive individuals: correlation with the aldosterone to renin ratio and urinary sodium.

Prostasin, a glycosylphosphatidylinositol (GPI)-anchored serine protease, activates the epithelial sodium (Na) channel (ENaC), and prostasin is released in extracellular fluids, including urine. Previous data have suggested a direct association between urinary prostasin and the activation of an aldosterone-driven pathway, but a quantitative association has never been demonstrated in normotensive subjects. Similarly, physiological relationships with natriuresis or possible gender- or female hormone-related changes in urinary prostasin concentrations have never been investigated. We measured urinary prostasin by enzyme-linked immunosorbent assay in 43 healthy normotensive subjects of similar age presenting different urinary Na levels and in 15 women during the menstrual cycle and after oral estro-progestinic contraceptive (OC) therapy. Exosomal urinary prostasin was also estimated by western blotting of samples from six healthy subjects twice during the morning. Urinary prostasin presented a wide range of values (from 0.5 to 18.9 nM) without gender differences. It was positively correlated with the aldosterone to renin ratio (ARR) but not with circulating aldosterone or renin individually. Urinary prostasin was directly correlated with U-Na levels (up to 200 nmol Na), whereas it decreased for higher Na concentrations. In women, no significant changes of prostasin concentration were observed during menstrual phases. After OC therapy, prostasin increased (from 2.37±1.27 to 4.85±5.28 nM), although the increase was not statistically different (P=0.07). Prostasin was detectable in urinary exosomes and displayed a pattern similar to urinary prostasin in relation to urinary Na. In conclusion, urinary prostasin correlates with the ARR, and it is physiologically modulated by natriuresis in normotensive individuals.

Global DNA hypomethylation in peripheral blood mononuclear cells as a biomarker of cancer risk.

BACKGROUND: Global DNA hypomethylation is an early molecular event in carcinogenesis. Whether methylation measured in peripheral blood mononuclear cells (PBMCs) DNA is a clinically reliable biomarker for early detection or cancer risk assessment is to be established. METHODS: From an original sample-set of 753 male and female adults (ages 64.8 ± 7.3 years), PBMCs DNA methylation was measured in 68 subjects with history of cancer at time of enrollment and 62 who developed cancer during follow-up. Age- and sex-matched controls for prevalent and incident cancer cases (n = 68 and 58, respectively) were also selected. Global DNA methylation was assessed by liquid chromatography/mass spectrometry (LC/MS). Methylenetetrahydrofolate reductase (MTHFR) 677C>T genotype and plasma folate concentrations were also determined for the known gene-nutrient interaction affecting DNA methylation. RESULTS: Cancer subjects had significantly lower PBMCs-DNA methylation than controls [4.39 (95% confidence intervals (CI), 4.25-4.53) vs. 5.13 (95% CI, 5.03-5.21) %mCyt/(mCyt+Cyt); P < 0.0001]. A DNA methylation threshold of 4.74% clearly categorized patients with cancer from controls so that those with DNA methylation less than 4.74% showed an increased prevalence of cancer than those with higher levels (91.5% vs. 19%; P < 0.001). Subjects with cancer at follow-up had, already at enrollment, reduced DNA methylation as compared with controls [4.34 (95% CI, 4.24-4.51) vs. 5.08 (95% CI, 5.05-5.22) %mCyt/(mCyt+Cyt); P < 0.0001]. Moreover, MTHFR677C>T genotype and folate interact for determining DNA methylation, so that MTHFR677TT carriers with low folate had the lowest DNA methylation and concordantly showed a higher prevalence of cancer history (OR, 7.04; 95% CI, 1.52-32.63; P = 0.013). CONCLUSIONS: Genomic PBMCs-DNA methylation may be a useful epigenetic biomarker for early detection and cancer risk estimation. IMPACT: This study identifies a threshold for PBMCs-DNA methylation to detect cancer-affected from cancer-free subjects and an at-risk condition for cancer based on genomic DNA methylation and MTHFR677C>T-folate status.

Low levels of serum paraoxonase activities are characteristic of metabolic syndrome and may influence the metabolic-syndrome-related risk of coronary artery disease.

Low concentrations of plasma high-density lipoprotein (HDLs) are characteristic in metabolic syndrome (MS). The antioxidant ability of HDLs is, at least in part, attributable to pleiotropic serum paraoxonase (PON1). Different PON1 activities have been assessed in 293 subjects with (n = 88) or without MS (n = 205) and with (n = 195) or without (n = 98) angiographically proven coronary artery disease (CAD). MS subjects had low PON1 activities, with a progressively decreasing trend by increasing the number of MS abnormalities. The activity versus 7-O-diethyl phosphoryl,3-cyano,4-methyl,7-hydroxycoumarin (DEPCyMC), which is considered a surrogate marker of PON1 concentration, showed the most significant association with MS, independently of both HDL and apolipoprotein A-I levels. Subjects with MS and low DEPCyMCase activity had the highest CAD risk (OR 4.34 with 95% CI 1.44-13.10), while no significant increase of risk was found among those with MS but high DEPCyMCase activity (OR 1.45 with 95% CI 0.47-4.46). Our results suggest that low PON1 concentrations are typical in MS and may modulate the MS-related risk of CAD.