-318C/T polymorphism of the CTLA-4 gene is an independent risk factor for RBC alloimmunization among sickle cell disease patients

Cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) molecule is expressed on T-lymphocyte membrane and negatively influences the antigen-presenting process. Reduced expression of CTLA-4 due to gene polymorphisms is associated with increased risk of autoimmune disorders, whose physiopathology is similar to that of post-transfusion red blood cell (RBC) alloimmunization. Our goal was to evaluate if polymorphisms of CTLA-4 gene that affect protein expression are associated with RBC alloimmunization. This was a case-control study in which 134 sickle cell disease (SCD) patients and 253 non-SCD patients were included. All patients were genotyped for the polymorphisms 49A/G and -318C/T of CTLA-4 gene. The genotype frequency of -318C/T differed significantly between alloimmunized and nonalloimmunized SCD patients, irrespective of clinical confounders (p = .016). SCD patients heterozygous for -318T allele presented higher risk of alloantibody development (OR: 5.4, CI: 1.15-25.6). In conclusion, the polymorphism -318C/T of CTLA-4 gene is associated with RBC alloimmunization among SCD patients. This highlights the role played by CTLA-4 on post-transfusion alloantibody development.

A Novel Aldosterone Antagonist Limits Renal Injury in 5/6 Nephrectomy

Aldosterone antagonists slow the progression of chronic kidney disease (CKD), but their use is limited by hyperkalemia, especially when associated with RAS inhibitors. We examined the renoprotective effects of Ly, a novel non-steroidal mineralocorticoid receptor (MR) blocker, through two experimental protocols: In Protocol 1, male Munich-Wistar rats underwent 5/6 renal ablation (Nx), being divided into: Nx+V, receiving vehicle, Nx+Eple, given eplerenone, 150 mg/kg/day, and Nx+Ly, given Ly, 20 mg/kg/day. A group of untreated sham-operated rats was also studied. Ly markedly raised plasma renin activity (PRA) and aldosterone, and exerted more effective anti-albuminuric and renoprotective action than eplerenone. In Protocol 2, Nx rats remained untreated until Day 60, when they were divided into: Nx+V receiving vehicle; Nx+L treated with losartan, 50 mg/kg/day; Nx+L+Eple, given losartan and eplerenone, and Nx+L+Ly, given losartan and Ly. Treatments lasted for 90 days. As an add-on to losartan, Ly normalized blood pressure and albuminuria, and prevented CKD progression more effectively than eplerenone. This effect was associated with strong stimulation of PRA and aldosterone. Despite exhibiting higher affinity for the MR than either eplerenone or spironolactone, Ly caused no hyperkalemia. Ly may become a novel asset in the effort to detain the progression of CKD.

Allogeneic pASC transplantation in humanized pigs attenuates cardiac remodeling post-myocardial infarction

Cell therapy repair strategies using adult mesenchymal stromal cells have shown promising evidence to prevent cardiac deterioration in rodents even in the absence of robust differentiation of the cells into cardiomyocytes. We tested whether increasing doses of porcine adipose-tissue derived mesenchymal stem cells (pASCs) increase cardiac tissue perfusion in pigs post-myocardial infarction (MI) receiving angiotensin-converting-enzyme inhibitor (ACE inhibitors) and Beta-blockers similarly to patients. Female pigs were subjected to MI induction by sponge permanent occlusion of left circumflex coronary artery (LCx) generating approximately 10% of injured LV area with minimum hemodynamic impact. We assessed tissue perfusion by real time myocardial perfusion echocardiography (RTMPE) using commercial microbubbles before and following pASCs treatment. Four weeks after the occlusion of the left circumflex artery, we transplanted placebo or pASCs (1, 2 and 4x10⁶ cells/Kg BW) into the myocardium. The highest dose of pASCs increased myocardial vessel number and blood flow in the border (56% and 3.7-fold, respectively) and in the remote area (54% and 3.9-fold, respectively) while the non-perfused scar area decreased (up to 38%). We also found an increase of immature collagen fibers, although the increase in total tissue collagen and types I and III was similar in all groups. Our results provide evidence that pASCs-induced stimulation of tissue perfusion and accumulation of immature collagen fibers attenuates adverse remodeling post-MI beyond the normal beneficial effects associated with ACE inhibition and beta-blockade.

Human Induced Pluripotent Stem (hiPS) Cells from Urine Samples: A Non-Integrative and Feeder-Free Reprogramming Strategy

Human induced pluripotent stem (hiPS) cell technology has already revolutionized some aspects of fundamental and applied research such as study of disease mechanisms and pharmacology screening. The first clinical trial using hiPS cell-derived cells began in Japan, only 10 years after the publication of the proof-of concept article. In this exciting context, strategies to generate hiPS cells have evolved quickly, tending towards non-invasive protocols to sample somatic cells combined with "safer" reprogramming strategies. In this unit, we describe a protocol combining both of these advantages to generate hiPS cells with episomal plasmid transfection from urine samples of individuals carrying the desired genotype. Based on previous published works, this simplified protocol requires minimal equipment and reagents, and is suitable both for scientists familiar with the hiPS cells technology and neophytes. HiPS cells displaying classical features of pluripotency and suitable for all desired downstream applications are generated rapidly (<10 weeks) and with high efficiency. © 2017 by John Wiley & Sons, Inc.

Role of Trimetazidine in Ischemic Preconditioning in Patients With Symptomatic Coronary Artery Disease

Ischemic preconditioning (IP) is a powerful cardioprotective cellular mechanism that has been related to the "warm-up phenomenon" or "walk-through" angina, and has been documented through the use of sequential exercise tests (ETs). It is known that several drugs, for example, cromokalim, pinacidil, adenosine, and nicorandil, can interfere with the cellular pathways of IP. The purpose of this article is to report the effect of the anti-ischemic agent trimetazidine (TMZ) on IP in symptomatic coronary artery disease (CAD) patients.We conducted a prospective study evaluating IP by the analysis of ischemic parameters in 2 sequential ETs. In phase I, without TMZ, patients underwent ET1 and ET2 with a 30-minute interval between them. In phase II, after 1 week of TMZ 35 mg twice daily, all patients underwent 2 consecutive ETs (ET3 and ET4). IP was considered present when the time to 1.0-mm segment ST on electrocardiogram deviation (T-1.0 mm) and rate pressure product (RPP) were greater in the second of 2 tests. The improvement in T-1.0 mm and RPP were compared in the 2 phases: without TMZ and after 1-week TMZ to assess the action of such drug in myocardial protective mechanisms. ETs were analyzed by 2 independent cardiologists.From 135 CAD patients screened, 96 met inclusion criteria and 62 completed the study protocol. Forty patients manifested IP by demonstrating an improvement in T-1.0 mm in ET2 compared with ET1, without the use of any drugs (phase I). In phase II, after 1-week TMZ, 26 patients (65%) did not show any incremental result in ischemic parameters in ET4 compared with ET3. Furthermore, of these patients, 8 (20%) had IP blockage.In this study, TMZ did not add any benefit to IP in patients with stable symptomatic CAD.

Early postnatal rat ventricle resection leads to long-term preserved cardiac function despite tissue hypoperfusion

One‐day‐old mice display a brief capacity for heart regeneration after apex resection. We sought to examine this response in a different model and to determine the impact of this early process on long‐term tissue perfusion and overall cardiac function in response to stress. Apical resection of postnatal rats at day 1 (P1) and 7 (P7) rendered 18 ± 1.0% and 16 ± 1.3% loss of cardiac area estimated by magnetic resonance imaging (MRI), respectively (P > 0.05). P1 was associated with evidence of cardiac neoformation as indicated by Troponin I and Connexin 43 expression at 21 days postresection, while in the P7 group mainly scar tissue replacement ensued. Interestingly, there was an apparent lack of uniform alignment of newly formed cells in P1, and we detected cardiac tissue hypoperfusion for both groups at 21 and 60 days postresection using SPECT scanning. Direct basal cardiac function at 60 days, when the early lesion is undetectable, was preserved in all groups, whereas under hemodynamic stress the degree of change on LVDEP, Stroke Volume and Stroke Work indicated diminished overall cardiac function in P7 (P < 0.05). Furthermore, the End‐Diastolic Pressure–Volume relationship and increased interstitial collagen deposition in P7 is consistent with increased chamber stiffness. Taken together, we provide evidence that early cardiac repair response to apex resection in rats also leads to cardiomyocyte neoformation and is associated to long‐term preservation of cardiac function despite tissue hypoperfusion.

We provide evidence that 1‐day‐old rats display early repair capacity after apex resection and this response is lost in 1‐week‐old animals similarly described for mice. The repair response is associated with long‐term preservation of overall cardiac function, despite the fact that repair is incomplete and there is tissue hypoperfusion at 21 and 60 day post injury.

Porcine adipose tissue-derived mesenchymal stem cells retain their proliferative characteristics, senescence, karyotype and plasticity after long-term cryopreservation

We and others have provided evidence that adipose tissue-derived mesenchymal stem cells (ASCs) can mitigate rat cardiac functional deterioration after myocardial ischemia, even though the mechanism of action or the relevance of these findings to human conditions remains elusive. In this regard, the porcine model is a key translational step, because it displays heart anatomic-physiological features that are similar to those found in the human heart. Towards this end, we wanted to establish the cultural characteristics of porcine ASCs (pASCs) with or without long-term cryostorage, considering that allogeneic transplantation may also be a future option. Compared to fresh pASCs, thawed cells displayed 90-95% viability and no changes in morphological characteristics or in the expression of surface markers (being pASCs characterized by positive markers CD29(+); CD90(+); CD44(+); CD140b(+); CD105(+); and negative markers CD31(-); CD34(-); CD45(-) and SLA-DR(-); n = 3). Mean population doubling time was also comparable (64.26±15.11 hours to thawed cells vs. 62.74±18.07 hours to fresh cells) and cumulative population doubling increased constantly until Passage 10 (P10) in the entire cell population, with a small and gradual increase in senescence (P5, 3.25%±0.26 vs. 3.47%±0.32 and P10, 9.6%±0.29 vs. 10.67%±1.25, thawed vs. fresh; SA-β-Gal staining). Chromosomal aberrations were not observed. In addition, under both conditions pASCs responded to adipogenic and osteogenic chemical cues in vitro. In conclusion, we have demonstrated the growth characteristics, senescence, and the capacity of pASCs to respond to chemical cues in vitro and have provided evidence that these properties are not influenced by cryostorage in 10% DMSO solution.

Shear stress-induced Ang II AT1 receptor activation: G-protein dependent and independent mechanisms

Mechanotransduction enables cells to sense and respond to stimuli, such as strain, pressure and shear stress (SS), critical for maintenance of cardiovascular homeostasis or pathological states. The angiotensin II type 1 receptor (AT1R) was the first G protein-coupled receptor described to display stretch-induced activation in cardiomyocytes independent of its ligand Ang II. Here, we assessed whether SS (15 dynes/cm(2), 10 min), an important mechanical force present in the cardiovascular system, activates AT1R independent of its ligand. SS induced extracellular signal-regulated kinase (ERK) activation, used as a surrogate of AT1R activation, in Chinese hamster ovary cells expressing the AT1R (CHO+AT1) but not in wild type cells (CHO). AT1R dependent SS-induced ERK activation involves Ca(2+) inflow and activation of Gαq since Ca(2+) chelator EGTA or Gαq-specific inhibitor YM-254890 decreased SS-induced ERK activation. On the other hand, the activation of JAK-2 and Src, two intracellular signaling molecules independent of G protein activation, were not differently modulated in the presence of AT1R. Also, ERK activation by SS was observed in CHO cells expressing the mutated AT1R DRY/AAY, which has impaired ability to activate Gαq dependent intracellular signaling. Altogether we provided evidence that SS activates AT1R in the absence of its ligand by both a G protein-dependent and -independent pathways. The biological relevance of these observations deserves to be further investigated since the novel mechanisms described extend the knowledge of the activation of GPCRs independent of its traditional ligand.

Using gene-network landscape to dissect genotype effects of TCF7L2 genetic variant on diabetes and cardiovascular risk

The single nucleotide polymorphism (SNP) within the TCF7L2 gene, rs7903146, is, to date, the most significant genetic marker associated with Type 2 diabetes mellitus (T2DM) risk. Nonetheless, its functional role in disease pathology is poorly understood. The aim of the present study was to investigate, in vascular smooth muscle cells from 92 patients undergoing aortocoronary bypass surgery, the contribution of this SNP in T2DM using expression levels and expression correlation comparison approaches, which were visually represented as gene interaction networks. Initially, the expression levels of 41 genes (seven TCF7L2 splice forms and 40 other T2DM relevant genes) were compared between rs7903146 wild-type (CC) and T2DM-risk (CT + TT) genotype groups. Next, we compared the expression correlation patterns of these 41 genes between groups to observe if the relationships between genes were different. Five TCF7L2 splice forms and nine genes showed significant expression differences between groups. RXRα gene was pinpointed as showing the most different expression correlation pattern with other genes. Therefore, T2DM risk alleles appear to be influencing TCF7L2 splice form's expression in vascular smooth muscle cells, and RXRα gene is pointed out as a treatment target candidate for risk reduction in individuals with high risk of developing T2DM, especially individuals harboring TCF7L2 risk genotypes.

CYBA C242T polymorphism is associated with obesity and diabetes mellitus in Brazilian hypertensive patients

AIMS

The CYBA C242T polymorphism has been associated with cardiovascular phenotypes such as hypertension and atherosclerosis, but available data are conflicting. This report investigated the impact of this variant on hypertension and metabolic determinants of cardiovascular risk in a large Brazilian sample.

METHODS

We cross-sectionally evaluated 1856 subjects (826 normotensive subjects and 1030 hypertensive patients) by clinical history, anthropometry, laboratory analysis and genotyping of the CYBA C242T polymorphism.

RESULTS

Genotype frequencies in the whole population were consistent with the Hardy-Weinberg equilibrium and genotype distributions were not different between hypertensive and normotensive subjects. Hypertensive patients with the CC genotype presented lower fasting plasma glucose levels (5.9 ± 0.1 vs. 6.2 ± 0.1 mmol/l, P = 0.020) and waist circumference (94.5 ± 0.6 vs. 96.3 ± 0.6 cm, P = 0.028) than CT + TT ones. Similarly, the prevalence of diabetes mellitus and obesity was also lower in hypertensive patients carrying the CC genotype (16% vs. 21%, P = 0.041; 36% vs. 43%, P = 0.029, respectively). In addition, multiple and logistic regression analysis demonstrated that the CYBA C242T polymorphism was associated with glucose levels, waist circumference, obesity and diabetes mellitus in hypertensive patients independently of potential confounders. Conversely, in normotensive subjects, no significant difference in studied variables was detected between the genotype groups.

CONCLUSIONS

These data suggest that the T allele of the CYBA C242T polymorphism may be used as a marker for adverse metabolic features in Brazilian subjects with systemic hypertension.

Reversible pulmonary trunk banding. VI: Glucose-6-phosphate dehydrogenase activity in rapid ventricular hypertrophy in young goats

OBJECTIVE

Increased myocardial glucose-6-phosphate dehydrogenase (G6PD) activity occurs in heart failure. This study compared G6PD activity in 2 protocols of right ventricle (RV) systolic overload in young goats.

METHODS

Twenty-seven goats were separated into 3 groups: sham (no overload), continuous (continuous systolic overload), and intermittent (four 12-hour periods of systolic overload paired with a 12-hour resting period). During a 96-hour protocol, systolic overload was adjusted to achieve a 0.7 RV/aortic pressure ratio. Echocardiographic and hemodynamic evaluations were performed before and after systolic overload every day postoperatively. After the study period, the animals were humanely killed for morphologic and G6PD tissue activity assessment.

RESULTS

A 92.1% and 46.5% increase occurred in RV and septal mass, respectively, in the intermittent group compared with the sham group; continuous systolic overload resulted in a 37.2% increase in septal mass. A worsening RV myocardial performance index occurred in the continuous group at 72 hours and 96 hours, compared with the sham (P < .039) and intermittent groups at the end of the protocol (P < .001). Compared with the sham group, RV G6PD activity was elevated 130.1% in the continuous group (P = .012) and 39.8% in the intermittent group (P = .764).

CONCLUSIONS

Continuous systolic overload for ventricle retraining causes RV dysfunction and upregulation of myocardial G6PD activity, which can elevate levels of free radicals by NADPH oxidase, an important mechanism in the pathophysiology of heart failure. Intermittent systolic overload promotes a more efficient RV hypertrophy, with better preservation of myocardial performance and and less exposure to hypertrophic triggers.

Hemojuvelin and hepcidin genes sequencing in Brazilian patients with primary iron overload

BACKGROUND

most hereditary hemochromatosis (HH) patients are homozygous for the p.C282Y mutation in the HFE gene. Some studies reported that HH phenotypic expression could be modulated by genetic factors such as HJV and HAMP gene mutations.

AIMS

the aims of this study were to identify HJV and HAMP mutations and to analyze their impact on HH phenotype in non-p.C282Y homozygous individuals.

METHODS

Twenty-four Brazilian patients with primary iron overload and non-p.C282Y homozygous genotype (transferrin saturation >50% in women and >60% in men and absence of secondary causes) were selected. Subsequent bidirectional sequencing of the HJV and HAMP exons was performed.

RESULTS

sequencing revealed a substitution in heterozygosis, c.929C > G, which corresponds to p.A310G polymorphism in HJV exon 4 (rs7540883). In the same gene, in another individual, an IVS1-36C > G intronic variant was detected in heterozygosis. In the HAMP gene, an IVS3 + 42G > A intronic variant was identified. There were six (25.0%) patients carrying a heterozygous genotype for the HFE p.C282Y and nine (37.5%) patients carrying a heterozygous genotype for the HFE p.H63D.

CONCLUSION

HJV p.A310G polymorphism and two intronic variants were found, but none of these alterations were associated with digenic inheritance with the HFE gene. Our data indicate that HJV and HAMP functional mutations are not frequent in these patients.

Challenges in using stem cells for cardiac repair

Of the many diseases discussed in the context of stem cell therapy, those concerning the heart account for almost one-third of the publications in the field. However, the long-term clinical outcomes have been disappointing, in part because of preclinical studies failing to optimize the timing, number, type, and method of cell delivery and to account for shape changes that the heart undergoes during failure. In situations in which cardiomyocytes have been used in cell therapy, their alignment and integration with host tissue have not been realized. Here we review the present status of direct delivery of stem cells or their derivative cardiomyocytes to the heart and the particular challenges each cell type brings, and consider where we should go from here.

Exercise training improves muscle vasodilatation in individuals with T786C polymorphism of endothelial nitric oxide synthase gene

Allele T at promoter region of the eNOS gene has been associated with an increase in coronary disease mortality, suggesting that this allele increases susceptibility for endothelial dysfunction. In contrast, exercise training improves endothelial function. Thus, we hypothesized that: 1) Muscle vasodilatation during exercise is attenuated in individuals homozygous for allele T, and 2) Exercise training improves muscle vasodilatation in response to exercise for TT genotype individuals. From 133 preselected healthy individuals genotyped for the T786C polymorphism, 72 participated in the study: TT ( n = 37; age 27 ± 1 yr) and CT+CC ( n = 35; age 26 ± 1 yr). Forearm blood flow (venous occlusion plethysmography) and blood pressure (oscillometric automatic cuff) were evaluated at rest and during 30% handgrip exercise. Exercise training consisted of three sessions per week for 18 wk, with intensity between anaerobic threshold and respiratory compensation point. Resting forearm vascular conductance (FVC, P = 0.17) and mean blood pressure ( P = 0.70) were similar between groups. However, FVC responses during handgrip exercise were significantly lower in TT individuals compared with CT+CC individuals (0.39 ± 0.12 vs. 1.08 ± 0.27 units, P = 0.01). Exercise training significantly increased peak VO2 in both groups, but resting FVC remained unchanged. This intervention significantly increased FVC response to handgrip exercise in TT individuals ( P = 0.03), but not in CT+CC individuals ( P = 0.49), leading to an equivalent FVC response between TT and CT+CC individuals (1.05 ± 0.18 vs. 1.59 ± 0.27 units, P = 0.27). In conclusion, exercise training improves muscle vasodilatation in response to exercise in TT genotype individuals, demonstrating that genetic variants influence the effects of interventions such as exercise training.

Rat adipose tissue-derived stem cells transplantation attenuates cardiac dysfunction post infarction and biopolymers enhance cell retention

Background

Cardiac cell transplantation is compromised by low cell retention and poor graft viability. Here, the effects of co-injecting adipose tissue-derived stem cells (ASCs) with biopolymers on cell cardiac retention, ventricular morphometry and performance were evaluated in a rat model of myocardial infarction (MI).

Methodology/Principal Findings

^99mTc-labeled ASCs (1×10⁶ cells) isolated from isogenic Lewis rats were injected 24 hours post-MI using fibrin a, collagen (ASC/C), or culture medium (ASC/M) as vehicle, and cell body distribution was assessed 24 hours later by γ-emission counting of harvested organs. ASC/F and ASC/C groups retained significantly more cells in the myocardium than ASC/M (13.8±2.0 and 26.8±2.4% vs. 4.8±0.7%, respectively). Then, morphometric and direct cardiac functional parameters were evaluated 4 weeks post-MI cell injection. Left ventricle (LV) perimeter and percentage of interstitial collagen in the spare myocardium were significantly attenuated in all ASC-treated groups compared to the non-treated (NT) and control groups (culture medium, fibrin, or collagen alone). Direct hemodynamic assessment under pharmacological stress showed that stroke volume (SV) and left ventricle end-diastolic pressure were preserved in ASC-treated groups regardless of the vehicle used to deliver ASCs. Stroke work (SW), a global index of cardiac function, improved in ASC/M while it normalized when biopolymers were co-injected with ASCs. A positive correlation was observed between cardiac ASCs retention and preservation of SV and improvement in SW post-MI under hemodynamic stress.

Conclusions

We provided direct evidence that intramyocardial injection of ASCs mitigates the negative cardiac remodeling and preserves ventricular function post-MI in rats and these beneficial effects can be further enhanced by administrating co-injection of ASCs with biopolymers.

Cell therapy attenuates cardiac dysfunction post myocardial infarction: effect of timing, routes of injection and a fibrin scaffold

Background

Cell therapy approaches for biologic cardiac repair hold great promises, although basic fundamental issues remain poorly understood. In the present study we examined the effects of timing and routes of administration of bone marrow cells (BMC) post-myocardial infarction (MI) and the efficacy of an injectable biopolymer scaffold to improve cardiac cell retention and function.

Methodology/Principal Findings

^99mTc-labeled BMC (6×10⁶ cells) were injected by 4 different routes in adult rats: intravenous (IV), left ventricular cavity (LV), left ventricular cavity with temporal aorta occlusion (LV⁺) to mimic coronary injection, and intramyocardial (IM). The injections were performed 1, 2, 3, or 7 days post-MI and cell retention was estimated by γ-emission counting of the organs excised 24 hs after cell injection. IM injection improved cell retention and attenuated cardiac dysfunction, whereas IV, LV or LV* routes were somewhat inefficient (<1%). Cardiac BMC retention was not influenced by timing except for the IM injection that showed greater cell retention at 7 (16%) vs. 1, 2 or 3 (average of 7%) days post-MI. Cardiac cell retention was further improved by an injectable fibrin scaffold at day 3 post-MI (17 vs. 7%), even though morphometric and function parameters evaluated 4 weeks later displayed similar improvements.

Conclusions/Significance

These results show that cells injected post-MI display comparable tissue distribution profile regardless of the route of injection and that there is no time effect for cardiac cell accumulation for injections performed 1 to 3 days post-MI. As expected the IM injection is the most efficient for cardiac cell retention, it can be further improved by co-injection with a fibrin scaffold and it significantly attenuates cardiac dysfunction evaluated 4 weeks post myocardial infarction. These pharmacokinetic data obtained under similar experimental conditions are essential for further development of these novel approaches.

Association of angiotensin-converting enzyme activity and polymorphism with echocardiographic measures in familial and nonfamilial hypertrophic cardiomyopathy

Angiotensin-converting enzyme (ACE) activity and polymorphism contribute significantly to the prognosis of patients with cardiomyopathy. The aim of this study was to determine the activity and type of ACE polymorphism in patients with familial and nonfamilial hypertrophic cardiomyopathy (HCM) and to correlate these with echocardiographic measurements (echo-Doppler). We studied 136 patients (76 males) with HCM (69 familial and 67 nonfamilial cases). Mean age was 41 +/- 17 years. DNA was extracted from blood samples for the polymerase chain reaction and the determination of plasma ACE levels. Left ventricular mass, interventricular septum, and wall thickness were measured. Mean left ventricular mass index, interventricular septum and wall thickness in familial and nonfamilial forms were 154 +/- 63 and 174 +/- 57 g/m(2) (P = 0.008), 19 +/- 5 and 21 +/- 5 mm (P = 0.02), and 10 +/- 2 and 12 +/- 3 mm (P = 0.0001), respectively. ACE genotype frequencies were DD = 35%, ID = 52%, and II = 13%. A positive association was observed between serum ACE activity and left ventricular mass index (P = 0.04). Logistic regression showed that ACE activity was twice as high in patients with familial HCM and left ventricular mass index >or=190 g/m(2) compared with the nonfamilial form (P = 0.02). No other correlation was observed between ACE polymorphisms and the degree of myocardial hypertrophy. In conclusion, ACE activity, but not ACE polymorphisms, was associated with the degree of myocardial hypertrophy in the patients with HCM.

Association between glutathione S-transferase polymorphisms and triglycerides and HDL-cholesterol

OBJECTIVE

Null genotypes of glutathione S-transferase (GSTs) exhibit absence of enzymatic activity and are hypothesized to modulate an increased risk of developing cardiovascular disease. The aim of this study was to identify the potential association between GSTM1 and GSTT1 deleted polymorphisms with cardiovascular risk factors and coronary atherosclerosis in two independent urban populations.

METHODS AND RESULTS

Genotype distribution of GSTM1 and GSTT1 deleted polymorphism were examined in a sample of 1577 individuals from the general population and a replication sample of 871 individuals submitted to coronary angiography. Triglycerides, HDL-cholesterol and the triglycerides/HDL ratio were significantly associated with a double-deleted genotype in individuals from the general population. These findings were replicated in a second, independent, population of individuals submitted to coronary angiography. In addition, coronary artery disease severity was also associated with GSTs genotypes and the risk conferred from GSTs genotype was mainly due to triglycerides/HDL ratio information.

CONCLUSIONS

The data suggest that the presence of a double deletion genotypes of the GSTM1 and GSTT1 genes is associated with hypertriglyceridemia and low HDL-cholesterol levels in humans. These novel findings may provide a new unexplored link between lipid metabolism and GST homeostasis.

Local TAT-p27Kip1 fusion protein inhibits cell proliferation in rat carotid arteries

INTRODUCTION

p27(Kip1) is a cyclin kinase inhibitor that induces cell cycle arrest. In this study, the efficacy of fusion protein TAT- p27(Kip1) to inhibit cell proliferation in rat perivascular injured carotid arteries was tested.

METHODS

The cDNA of p27(Kip1) and GFP (green fluorescein protein) fused to the TAT epitope, which allows cell penetration, yielded TAT-p27 (Kip1) and TAT-GFP fusion proteins. In vitro biological activity on cell proliferation was evaluated by [(3)H] thymidine DNA incorporation in rabbit aortic endothelial cells (REC). An in vivo model used a silicone collar filled with saline positioned around the carotid vessel for 14 days to produce an increased adventitia cross-sectional area.

RESULTS

TAT-p27(Kip1) inhibited REC proliferation in vitro using either 100, 200, and 500 nM compared to control (88.2 +/- 4.4, 81.3 +/- 7, 71.9 +/- 4.2 vs. 100 +/- 6.7%, N = 3, respectively, p < 0.05). This response was stable for purified proteins stored at -20*C for at least 23 days. In vivo , TAT-p27(Kip1) solution reduced adventitia cross-sectional area in a dose-dependent manner compared to TAT-GFP (area in mm(2) - TAT-p27(Kip1): 200 nM, 0.160 +/- 0.018; 500 nM, 0.050 +/- 0.005 vs. TAT-GFP: 500 nM, 0.595 +/- 0.066 vs. the contralateral: 0.047 +/- 0.005, N = 7, p < 0.01).

CONCLUSION

Taken together, these results provide evidence that TAT-p27(Kip1) can inhibit vascular cells proliferation. It is the first successful demonstration that the cell permeable TAT-p27(Kip1) has potential as a vascular anti-proliferative agent.

Congenic strains provide evidence that four mapped loci in chromosomes 2, 4, and 16 influence hypertension in the SHR

To dissect the genetic architecture controlling blood pressure (BP) regulation in the spontaneously hypertensive rat (SHR) we derived congenic rat strains for four previously mapped BP quantitative trait loci (QTLs) in chromosomes 2, 4, and 16. Target chromosomal regions from the Brown Norway rat (BN) averaging 13-29 cM were introgressed by marker-assisted breeding onto the SHR genome in 12 or 13 generations. Under normal salt intake, QTLs on chromosomes 2a, 2c, and 4 were associated with significant changes in systolic BP (13, 20, and 15 mmHg, respectively), whereas the QTL on chromosome 16 had no measurable effect. On high salt intake (1% NaCl in drinking water for 2 wk), the chromosome 16 QTL had a marked impact on SBP, as did the QTLs on chromosome 2a and 2c (18, 17, and 19 mmHg, respectively), but not the QTL on chromosome 4. Thus these four QTLs affected BP phenotypes differently: 1) in the presence of high salt intake (chromosome 16), 2) only associated with normal salt intake (chromosome 4), and 3) regardless of salt intake (chromosome 2c and 2a). Moreover, salt sensitivity was abrogated in congenics SHR.BN2a and SHR.BN16. Finally, we provide evidence for the influence of genetic background on the expression of the mapped QTLs individually or as a group. Collectively, these data reveal previously unsuspected nuances of the physiological roles of each of the four mapped BP QTLs in the SHR under basal and/or salt loading conditions unforeseen by the analysis of the F2 cross.

TCF7L2 variant genotypes and type 2 diabetes risk in Brazil: significant association, but not a significant tool for risk stratification in the general population

Background

Genetic polymorphisms of the TCF7L2 gene are strongly associated with large increments in type 2 diabetes risk in different populations worldwide. In this study, we aimed to confirm the effect of the TCF7L2 polymorphism rs7903146 on diabetes risk in a Brazilian population and to assess the use of this genetic marker in improving diabetes risk prediction in the general population.

Methods

We genotyped the single nucleotide polymorphisms (SNP) rs7903146 of the TCF7L2 gene in 560 patients with known coronary disease enrolled in the MASS II (Medicine, Angioplasty, or Surgery Study) Trial and in 1,449 residents of Vitoria, in Southeast Brazil. The associations of this gene variant to diabetes risk and metabolic characteristics in these two different populations were analyzed. To access the potential benefit of using this marker for diabetes risk prediction in the general population we analyzed the impact of this genetic variant on a validated diabetes risk prediction tool based on clinical characteristics developed for the Brazilian general population.

Results

SNP rs7903146 of the TCF7L2 gene was significantly associated with type 2 diabetes in the MASS-II population (OR = 1.57 per T allele, p = 0.0032), confirming, in the Brazilian population, previous reports of the literature. Addition of this polymorphism to an established clinical risk prediction score did not increased model accuracy (both area under ROC curve equal to 0.776).

Conclusion

TCF7L2 rs7903146 T allele is associated with a 1.57 increased risk for type 2 diabetes in a Brazilian cohort of patients with known coronary heart disease. However, the inclusion of this polymorphism in a risk prediction tool developed for the general population resulted in no improvement of performance. This is the first study, to our knowledge, that has confirmed this recent association in a South American population and adds to the great consistency of this finding in studies around the world. Finally, confirming the biological association of a genetic marker does not guarantee improvement on already established screening tools based solely on demographic variables.

AT1 receptor participates in the cardiac hypertrophy induced by resistance training in rats

Resistance training is accompanied by cardiac hypertrophy, but the role of the renin-angiotensin system (RAS) in this response is elusive. We evaluated this question in 36 male Wistar rats divided into six groups: control ( n = 6); trained ( n = 6); control + losartan (10 mg·kg−1·day−1, n = 6); trained + losartan ( n = 6); control + high-salt diet (1%, n = 6); and trained + high-salt diet (1%, n = 6). High salt was used to inhibit the systemic RAS and losartan to block the AT1 receptor. The exercise protocol consisted of: 4 × 12 bouts, 5×/wk during 8 wk, with 65–75% of one repetition maximum. Left ventricle weight-to-body weight ratio increased only in trained and trained + high-salt diet groups (8.5% and 10.6%, P < 0.05) compared with control. Also, none of the pathological cardiac hypertrophy markers, atrial natriuretic peptide, and αMHC (α-myosin heavy chain)-to-βMHC ratio, were changed. ACE activity was analyzed by fluorometric assay (systemic and cardiac) and plasma renin activity (PRA) by RIA and remained unchanged upon resistance training, whereas PRA decreased significantly with the high-salt diet. Interestingly, using Western blot analysis and RT-PRC, no changes were observed in cardiac AT2 receptor levels, whereas the AT1 receptor gene (56%, P < 0.05) and protein (31%, P < 0.05) expressions were upregulated in the trained group. Also, cardiac ANG II concentration evaluated by ELISA remained unchanged (23.27 ± 2.4 vs. 22.01 ± 0.8 pg/mg, P > 0.05). Administration of a subhypotensive dose of losartan prevented left ventricle hypertrophy in response to the resistance training. Altogether, we provide evidence that resistance training-induced cardiac hypertrophy is accompanied by induction of AT1 receptor expression with no changes in cardiac ANG II, which suggests a local activation of the RAS consistent with the hypertrophic response.

Frequency of 22q11.2 microdeletion in sporadic non-syndromic tetralogy of Fallot cases

BACKGROUND

Tetralogy of Fallot (TOF) is a congenital conotruncal heart defect commonly found in DiGeorge (DGS) and velocardiofacial (VCFS) syndromes. The deletion of chromosome 22q11 has also been demonstrated in sporadic or familial cases of TOF. The aim of the present study was to investigate the frequency of del22q11 in patients with non-syndromic TOF seen at a tertiary Pediatric Cardiology care center.

METHOD

One hundred and twenty three non-syndromic TOF patients were selected and evaluated by history, physical examination and review of medical records. Venous blood was drawn for genomic DNA extraction after informed consent 22q11 microdeletion diagnosis was conducted through a standardized SNP genotyping assay and consecutive homozygosity mapping. Phenotype-genotype correlations regarding cardiac anatomy were conducted.

RESULTS

We evaluated 123 non-syndromic TOF patients for a 22q11 deletion. 105 (85.4%) patients presented pulmonary stenosis and 18 (14.6%) had pulmonary atresia. Eight patients (6.5%) were found to have a deletion. Of the deleted patients, three (37.5%) presented pulmonary atresia. We have verified a tendency towards a higher prevalence of pulmonary atresia when comparing TOF patients with and without 22q11 microdeletion.

CONCLUSIONS

22q11.2 deletion in non-syndromic TOF patients is present in approximately 6% of patients. We suggest a tendency towards a higher prevalence of pulmonary atresia in non-syndromic TOF patients with 22q11 microdeletion. Molecular genetic screening of non-syndromic TOF patient may be important for the correct care of these patients and a more specific genetic diagnostic and counseling.

Anabolic steroids induce cardiac renin-angiotensin system and impair the beneficial effects of aerobic training in rats

We evaluated the effects of swimming and anabolic steroids (AS) on ventricular function, collagen synthesis, and the local renin-angiotensin system in rats. Male Wistar rats were randomized into control (C), steroid (S; nandrolone decanoate; 5 mg/kg sc, 2x/wk), steroid + losartan (SL; 20 mg.kg(-1).day(-1)), trained (T), trained + steroid (T+S), and trained + steroid + losartan (T+SL; n = 14/group) groups. Swimming was performed 5 times/wk for 10 wk. Serum testosterone increased in S and T+S. Resting heart rate was lower in T and T+S. Percent change in left ventricular (LV) weight-to-body weight ratio increased in S, T, and T+S. LV systolic pressure declined in S and T+S. LV contractility increased in T (P < 0.05). LV relaxation increased in T (P < 0.05). It was significantly lower in T+S compared with C. Collagen volumetric fraction (CVF) and hydroxyproline were higher in S and T+S than in C and T (P < 0.05), and the CVF and LV hypertrophy were prevented by losartan treatment. LV-ANG I-converting enzyme activity increased (28%) in the S group (33%), and type III collagen synthesis increased (56%) in T+S but not in T group. A positive correlation existed between LV-ANG I-converting enzyme activity and collagen type III expression (r(2) = 0.88; P < 0.05, for all groups). The ANG II and angiotensin type 1a receptor expression increased in the S and T+S groups but not in T group. Supraphysiological doses of AS exacerbated the cardiac hypertrophy in exercise-trained rats. Exercise training associated with AS induces maladaptive remodeling and further deterioration in cardiac performance. Exercise training associated with AS causes loss of the beneficial effects in LV function induced by exercising. These results suggest that aerobic exercise plus AS increases cardiac collagen content associated with activation of the local renin-angiotensin system.

Exercise training improves the net balance of cardiac Ca2+ handling protein expression in heart failure

The molecular basis of the beneficial effects associated with exercise training (ET) on overall ventricular function (VF) in heart failure (HF) remains unclear. We investigated potential Ca2+ handling abnormalities and whether ET would improve VF of mice lacking α2A- and α2C-adrenoceptors (α2A/α2CARKO) that have sympathetic hyperactivity-induced HF. A cohort of male wild-type (WT) and congenic α2A/α2CARKO mice in a C57BL/J genetic background (5–7 mo of age) was randomly assigned into untrained and trained groups. VF was assessed by two-dimensional guided M-mode echocardiography. Cardiac myocyte width and ventricular fibrosis were evaluated with a computer-assisted morphometric system. Sarcoplasmic reticulum Ca2+ ATPase (SERCA2), phospholamban (PLN), phospho-Ser16-PLN, phospho-Thr17-PLN, phosphatase 1 (PP1), and Na+-Ca2+ exchanger (NCX) were analyzed by Western blotting. ET consisted of 8-wk running sessions of 60 min, 5 days/wk. α2A/α2CARKO mice displayed exercise intolerance, systolic dysfunction, increased cardiac myocyte width, and ventricular fibrosis paralleled by decreased SERCA2 and increased NCX expression levels. ET in α2A/α2CARKO mice improved exercise tolerance and systolic function. ET slightly reduced cardiac myocyte width, but unchanged ventricular fibrosis in α2A/α2CARKO mice. ET significantly increased the expression of SERCA2 (20%) and phospho-Ser16-PLN (63%), phospho-Thr17-PLN (211%) in α2A/α2CARKO mice. Furthermore, ET restored NCX and PP1 expression in α2A/α2CARKO to untrained WT mice levels. Thus, we provide evidence that Ca2+ handling is impaired in this HF model and that overall VF improved upon ET, which was associated to changes in the net balance of cardiac Ca2+ handling proteins.

ACE gene dosage modulates pressure-induced cardiac hypertrophy in mice and men

The influence of genetic factors on complex phenotypes is context dependent, posing a challenge to quantify the role of single gene variants on this process. Moreover, redundancy and reserve capacity among control systems prevent most physiological stimuli to destabilize these processes. To test whether small gene perturbation can disrupt this equilibrium under pathological conditions, mice harboring one, two, or three copies of the angiotensin converting enzyme ( Ace) gene were submitted to 3 and 6 wk of pressure overload (PO). Direct systolic blood pressure (SBP), as an index of cardiac afterload, and left ventricle mass index (LVMI) were measured. LVMI under normotension was the same regardless of the Ace genotype, but the slopes of the LVMI/SBP curves increased in the three- vs. one-copy group by ∼50% upon 3- or 6-wk PO. Angiotensin II AT1 receptor blocker treatment produced a significant pressure independent decrease in the LVMI/SBP ratio. Unlike the one-copy group, PO resulted in a significant reduction in angiotensinogen and an increase in Ace mRNA expression accompanied by an increase in cardiac angiotensin II levels in the three-copy group. Similarly, the human ACE D gene variant influenced cardiac mass, estimated by Sokolov-Lyon index, in a sample of 1,507 individuals from an urban population only in individuals in the 4th quartile of the blood pressure distribution. Collectively, these data provide direct evidence that ACE gene dosage per se does not influence cardiac mass but upon a pathological stimulus, such as elevation in blood pressure, it modulates cardiac mass in both mice and humans.

Apolipoprotein E4 genotype increases the risk of postoperative cognitive dysfunction in patients undergoing coronary artery bypass graft surgery

AIM

The aim of this study was to investigate the association between the presence of ApoE4 and the incidence of postoperative cognitive dysfunction (POCD) after cardiac surgery.

METHODS

Eighty-seven adult patients undergoing elective coronary artery bypass graft surgery were observed prospectively at a university tertiary care hospital. All patients were evaluated with the Mini-Mental State Examination (MMSE) and the Glasgow Coma Scale (GCS) for cognitive function and mental status preoperatively, 24 h after surgery and at postoperative day 6. Patients were genotyped for the ApoE polymorphism. The association between ApoE genotype and MMSE evolution was studied by using repeated measures ANOVA.

RESULTS

Both the presence of at least one ApoE4 allele and POCD were verified in 21.8% of subjects. The presence of the ApoE4 allele was significantly associated with a worse MMSE score evolution (P=0.04).

CONCLUSION

This study suggests an association between ApoE4 and early POCD, but further studies are needed to clarify a causative association. Such new studies should include a more homogenous patient sample and a longer follow-up.

Effect of polymorphisms of the MTHFR and APOE genes on susceptibility to diabetes and severity of diabetic retinopathy in Brazilian patients

Diabetes mellitus (DM) is a highly prevalent complex genetic disorder. There has been a worldwide effort in the identification of susceptibility genes for DM and its complications, and the 5-10-methylenetetrahydrofolate reductase (MTHFR) and apolipoprotein-E (APOE) genes have been considered good candidate susceptibility genes to this condition. The objectives of the present study were to determine if the 677T MTHFR and epsilon2/epsilon3/epsilon4 APOE alleles are risk factors for DM and for severity of diabetic retinopathy (DR). A total of 248 individuals were studied: 107 healthy individuals and 141 diabetic patients (46 with type 1 diabetes and 95 with type 2 diabetes), who also had DR (81 with non-proliferative DR and 60 with proliferative DR). The polymorphisms were analyzed by PCR followed by digestion with restriction enzyme or the single-nucleotide primer extension method. No evidence of association between the 677TT genotype of MTHFR gene and DM [cases: TT = 10/95 (10.6%); controls: TT = 14/107 (13%)] or with severity of DR was observed [cases: TT = 5/60 (8.5%); controls: TT = 9/81 (11.1%); P > 0.05]. We also did not find evidence of an association between APOE alleles and proliferative DR (epsilon2, epsilon3 and epsilon4 in cases: 9, 76, and 15%, and in controls: 5, 88, and 12%, respectively) but the carriers of epsilon2 allele were more frequent among patients with type 2 DM and DR than in controls [cases: 15/95 (15.8%); controls: 7/107 (6.5%); P < 0.05]. Therefore, our results suggest that the epsilon2 allele/APOE might be a risk factor for diabetes in the Brazilian population.

PCR screening for 22q11.2 microdeletion: Development of a new cost-effective diagnostic tool

BACKGROUND

Del22q11.2 syndrome is the most frequent known chromosomal microdeletion syndrome. Previous studies suggest that a substantial number of patients with congenital heart disease have a 22q11 deletion. The molecular diagnosis of Del22q11.2 is usually made by fluorescence in situ hybridization, an expensive and not widely available technique. We developed an efficient and cost-effective PCR SNP assay designed for the screening of 22q11.2 deletion through consecutive homozygosity.

METHODS

Through the screening of dbSNP we have selected SNP markers located in the 22q11.2 microdeleted region. Population heterozygosities were determined in 213 normal individuals. Designed assays consisted of PCR amplification followed by restriction enzyme digestion. Fragments generated were visualized on agarose gel and genotyped.

RESULTS

Selected markers were: rs5748411, rs2238778, rs4819523 and rs4680. All selected markers were localized in the 22q11.2 deleted region. Allele and genotype frequencies of all selected markers were under Hardy-Weinberg equilibrium. Selected SNPs were not in linkage disequilibrium. Predicted assay specificity was estimated to be 92.86% in the Brazilian population.

CONCLUSIONS

The use of consecutive homozygosity in this SNP-based diagnostic test may be used as a cost-effective tool in reference molecular genetics laboratories.

DISSOCIATION OF BLOOD PRESSURE AND SYMPATHETIC ACTIVATION OF RENIN RELEASE IN SINOAORTIC-DENERVATED RATS

1. Blood pressure (BP) and heart rate (HR) increase 6 and 24 h after sinoaortic baroreceptor denervation (SAD), whereas plasma renin activity (PRA) and renal renin mRNA levels remain unchanged. We postulated that a simultaneous rise in BP could offset the expected activation of renin associated with an increased renal sympathetic discharge secondary to SAD. 2. To test this hypothesis, the increase in BP associated with the onset of SAD was prevented by a continuous infusion of sodium nitroprusside (SNP; 30 microg/kg per h). Changes were measured in five groups of conscious adult male Wistar rats: (i) sham; (ii) SAD; (iii) SAD rats in which the BP was prevented from increasing by infusion of SNP; (iv) sham rats in which the BP was increased by 30% by infusion of phenylephrine (PE; 1.5-2.0 mL/h); and (v) SNP + PE for 3 h by infusion as above. 3. As expected, BP and heart rate (HR) increased significantly following SAD compared with sham rats (152 +/- 4 vs 116 +/- 3 mmHg, respectively, for BP and 503 +/- 6 vs 345 +/- 13 b.p.m., respectively for HR; n = 5; P < 0.05) but remained unchanged when SNP was infused for 3 h (106 +/- 1 mmHg and 455 +/- 9 b.p.m., respectively; n = 5; P < 0.05). 4. Similarly, BP and HR increased with PE infusion compared with PE + SNP (138 +/- 9.9 vs 113 +/- 2.3 mmHg for BP, respectively, and 325 +/- 9 vs 423 +/- 18 b.p.m. for HR, respectively; n = 5; P < 0.05). 5. Plasma renin activity remained unchanged in SAD compared with sham rats (1.67 +/- 0.35 vs 1.05 +/- 0.17 ng angiotensin (Ang) I/mL per h), but increased significantly when hypertension was prevented (5.86 +/- 0.77 ng AngI/mL per h; n = 5; P < 0.05). Renin mRNA levels in the kidneys were unchanged in all groups. 6. These results show that an elevation in BP appears to offset increased renal sympathetic discharge with no change in PRA.

Phenotypic characteristics associated with hypertension in patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) causes secondary hypertension. However, the reasons why the prevalence of hypertension among OSA patients varies widely (35-70%) are not clear. We sought to investigate the phenotypic characteristics of patients with and without hypertension among OSA patients who were matched for disease severity. We studied 152 OSA patients (76 normotensive and 76 hypertensive) diagnosed by polysomnography. Detailed phenotypic characteristics, including laboratorial analysis, were determined in all patients. Univariate analysis followed by multiple logistic regression analysis was used to identify variables that were independently associated with hypertension. The apnea-hypopnea index in normotensive and hypertensive patients was similar (48+/-26 and 48+/-26 events/h, respectively) as well as minimum arterial oxygen saturation (76+/-10 and 75+/-10%, respectively) and total sleep time with oxyhaemoglobin saturation <90% (25+/-25 and 28+/-26%, respectively). Hypertensive patients were older (57+/-11 vs 47+/-12 years; P<0.001), had a higher body mass index (BMI; 34+/-7 vs 30+/-5 kg/m(2); P<0.001), had a higher frequency of women (37 vs 8%; P<0.001), had a higher incidence of diabetes (25 vs 6%; P=0.002) and a higher family history of hypertension (75 vs 42%; P=0.01) than did the normotensive patients. Multiple logistic regression analysis indicated that age (P=0.004), familial history of hypertension (P=0.004), BMI (P=0.04) and female sex (P=0.03) were the independent variables associated with hypertension. We concluded that increasing age and BMI, familial history of hypertension as well as female gender are phenotypic characteristics associated with hypertension among OSA patients with similar disease severity.

Holt-Oram syndrome presenting as agenesis of the left pericardium

We report on a case of a 60-year-old man with progressive heart failure, mitral and aortic valve insufficiency and bilateral asymmetrical skeletal upper-limb deformities. Central to the suspicion of Holt-Oram syndrome in this patient was the surgical finding of agenesis of the left pericardium. A Holt-Oram syndrome diagnostic was confirmed through molecular analysis of the TBX5 gene. A new amino acid substitution at position 61 of the TBX5 gene was identified and confirmed the clinical diagnosis of Holt-Oram syndrome. The clinical presentation of the present case broadens the clinical spectrum of Holt-Oram syndrome and point out the importance of Tbx 5 in pericardium development. It is still an unstudied issue whether TBX5 mutations may also be present in other clinical presentations where absence of the pericardium is a feature.

Endothelial nitric oxide synthase gene variant modulates the relationship between serum cholesterol levels and blood pressure in the general population: New evidence for a direct effect of lipids in arterial blood pressure

BACKGROUND

A causal relationship between plasma cholesterol and blood pressure remains poorly understood. It has been postulated that the decrease in nitric oxide (NO) availability is a potential mechanism by which hypercholesterolemia may stimulate blood pressure elevation. However, evidence supporting the role of the L-arginine-NO pathway on the relationship between hypertension and hypercholesterolemia is still lacking.

METHODS AND RESULTS

We tested for an association of the expressed NO synthase (eNOS) Glu298Asp gene variant and plasma levels of lipids and lipoproteins in the determination of systolic blood pressure levels in a 1577 individuals randomly selected from the general population. Significant interactions could be disclosed either between the Glu298Asp gene variant and total-cholesterol (p = 0.02), log-transformed triglycerides (p = 0.004) or non-HDL-cholesterol (p = 0.003) in the determination of systolic blood pressure. In addition, although the presence of the AspAsp genotype did not significantly increase the risk of hypertension in individuals in the 50% lowest percentile of total-cholesterol, presence of this genotype significantly increased the risk of hypertension in individuals in the 50% highest percentile. Finally, in a multiple logistic regression model adjusting for age, sex, diabetes, ethnicity, smoking status and BMI, the AspAsp genotype significantly increased the risk of hypertension only in individuals with total-cholesterol above 209 mg/dL (p = 0.05, odds ratios (OR) = 2.0).

CONCLUSION

Taken together, these results provide evidence supporting the role of the eNOS Glu298Asp gene variant in modulating blood pressure through a relationship with lipid levels.