Angiotensin-(1–7) Modulates Angiotensin II-Induced Vasoconstriction in Human Mammary Artery

Angiotensin-(1-7) Restores Microcirculation Profiles in Acute Pancreatitis: Secret of Telomerase Reverse Transcriptase

OBJECTIVES

The aim of this study was to investigate whether angiotensin (Ang)-(1-7)-mediated restoration of pancreatic microcirculation profiles and endothelial injury is associated with the expression of telomerase reverse transcriptase (TERT).

METHODS

Wild-type, TERT transgene, and TERT knockdown mice were used in this study, and acute pancreatitis model was induced by intraperitoneal injection of cerulein and lipopolysaccharide (LPS). Pancreatitis was confirmed by histopathology and serum amylase levels. Pancreatic microcirculation function was assessed by laser Doppler. Endothelial injury model was established by exposing endothelial cells to LPS. Proinflammatory cytokines were detected using enzyme-linked immunosorbent assay, endothelial permeability was detected using transwell assay, and mitochondrial dysfunction and mitochondrial reactive oxygen species (mtROS) were determined by performing confocal microscopy.

RESULTS

The effects of Ang-(1-7) in the treatment of pancreatic microcirculation dysfunction were associated with TERT expression. In addition, Ang-(1-7) protected against endothelial cell lesions via inhibiting the increase in endothelial cell permeability and release of proinflammatory cytokines in a TERT-dependent manner. Furthermore, TERT was involved in Ang-(1-7)-mediated attenuation of mitochondrial dysfunction and mtROS in LPS-induced endothelial cells.

CONCLUSIONS

Angiotensin-(1-7) restores pancreatic microcirculation profiles and reverses endothelial injury by inhibiting mtROS production and mitochondrial dysfunction in a TERT-dependent manner.

Angiotensin II-induced endothelial dysfunction: Impact of sex, genetic background, and rho kinase

The renin-angiotensin system (RAS) contributes to vascular disease with multiple cardiovascular risk factors including hypertension. As a major effector within the RAS, angiotensin II (Ang II) activates diverse signaling mechanisms that affect vascular biology. Despite the impact of such vascular pathophysiology, our understanding of the effects of Ang II in relation to the function of endothelial cells is incomplete. Because genetic background and biological sex can be determinants of vascular disease, we performed studies examining the direct effects of Ang II using carotid arteries from male and female mice on two genetic backgrounds, C57BL/6J and FVB/NJ. Although FVB/NJ mice are much less susceptible to atherosclerosis than C57BL/6J, the effects of Ang II on endothelial cells in FVB/NJ are poorly defined. Overnight incubation of isolated arteries with Ang II (10 nmol/L), impaired endothelial function in both strains and sexes by approximately one-half (p < 0.05). To examine the potential mechanistic contribution of Rho kinase (ROCK), we treated arteries with SLX-2119, an inhibitor with high selectivity for ROCK2. In both male and female mice of both strains, SLX-2119 largely restored endothelial function to normal, compared to vessels treated with vehicle. Thus, Ang II-induced endothelial dysfunction was observed in both FVB/NJ and C57BL/6J mice. This effect was sex-independent. In all groups, effects of Ang II were reversed by inhibition of ROCK2 with SLX-2119. These studies provide the first evidence that ROCK2 may be a key contributor to Ang II-induced endothelial dysfunction in both sexes and in mouse strains that differ in relation to other major aspects of vascular disease.

Angiotensin-(1-7) oral formulation improves physical performance in mountain bike athletes: a double-blinded crossover study

BACKGROUND

The ECA2/Ang-(1-7)/Mas axis is shown to be involved in effects mediated by physical exercise, as it can induce the release of nitric oxide (ON) and bradykinin (BK), which are potent vasodilators. The vasodilating action the NO/BK can contribute to increased metabolic efficiency in muscle tissue and central nervous system. The formulation HPβ-CD-Ang-(1-7) through its mechanisms of action can be a promising supplement to aid in the maintenance and improvement of performance and may also favor recovery during competitions. The premise of this study was to investigate the effects of acute oral supplementation HPβ-CD-Ang-(1-7) on the performance of mountain bike (MTB) practitioners.

METHODS

Fourteen recreational athletes, involved in training programs for at least one year, participated in this crossover design study. Subjects underwent two days of testing with a seven-day interval. HPβ-CD-Ang-(1-7) (1.75 mg) and HPβCD-Placebo were provided in capsules three hours prior to tests. To determine the safety of the HPβ-CD-Ang-(1-7) formulation associated with physical effort, cardiovascular parameters heart rate (HR) and blood pressure (BP) were analyzed. Physical performance was measured using maximal oxygen uptake (VO2), total exercise time (TET), mechanical work (MW), mechanical efficiency (ME), and rating of perceived exertion (RPE). Respiratory exchange coefficient (REC), lactate and non-esterified fatty acids (NEFAs) were measured. Maximal incremental tests were performed on a progressively loaded leg cycle ergometer.

RESULTS

There were no significant differences in terms of HR or BP at rest and maximum effort between the HPβ-CD-Ang-(1-7) and placebo groups. The VO2max showed significant differences (p = 0.04). It was higher in the Ang-(1-7)condition (66.15 mlO2.kg- 1.min- 1) compared to the placebo (60.72 mlO2.kg- 1.min- 1). This was also observed for TET (Ang-(1-7) 39.10 min vs. placebo 38.14 min; p = 0.04), MW (Ang-(1-7) 156.7 vs. placebo 148.2; p = 0.04), and at the lowest RPE (Ang-(1-7) vs. placebo; p = 0.009). No significant differences were observed for REC, NEFAs, or Lactate.

CONCLUSIONS

These results suggest that HPβ-CD-Ang-(1-7) improves the physical performance of MTB recreational athletes and could be a promising supplement.

TRIAL REGISTRATION

RBR-2 × 56pw8, registered January 15th, 2021. The study was prospectively registered.

Effects of inverted photoperiods on the blood pressure and carotid artery of spontaneously hypertensive rats and Wistar-Kyoto rats

OBJECTIVE

The objective of this study was to investigate the effects of inverted photoperiods on the blood pressure and carotid arteries in spontaneously hypertensive rats (SHRs) and Wistar-Kyoto (WKY) rats (homologous control group).

METHODS AND RESULTS

This study used two inverted photoperiods [inverted light:dark (ILD)16 : 8 and ILD12 : 12] to create the model. A total of 27 male SHR and 27 male WKY rats were randomly divided into six groups (nine rats per group): SHR (LD12 : 12), SHR (ILD16 : 8), SHR (ILD12 : 12), WKY (LD12 : 12), WKY (ILD16 : 8) and WKY (ILD12 : 12). We recorded the trajectory of the activity rhythm of the rats and performed carotid vascular ultrasound examination, MRI (arterial spin labelling) analysis and carotid biopsy. The results showed that inverted photoperiods increased the blood pressure, carotid intima-media thickness, resistance index and blood flow velocity. In addition, inverted photoperiods led to the development of carotid arterial thrombosis, significantly reduced cerebral blood flow and increased the number of collagen fibres. Moreover, it increased the expression of angiotensin receptor and low-density lipoprotein receptor in the carotid arteries, leading to decreased expression of 3-hydroxy-3-methylglutaryl-Coenzyme A reductase and nitric oxide synthase. Inverted photoperiods induced the formation of atherosclerotic plaque. Multiple results of SHR were worse than those of WKY rats.

CONCLUSION

Taken together, inverted photoperiods can produce a series of adverse consequences on blood pressure and carotid arteries. Hypertension can aggravate the adverse effects of inverted photoperiods.

Angiotensin-(1-7) receptor Mas antagonist (A779) influenced gliosis and reduced synaptic density in the spinal cord after peripheral axotomy

The peptide angiotensin-(1-7) [Ang (1-7)] and its receptor Mas are involved in controlling arterial pressure and display actions on the nervous system. In a previous study, our laboratory showed that A779 [(peptidyl antagonist of the Ang-(1-7)] treatment had a negative effect following a lesion of the sciatic nerve, possibly by delaying the responses of Schwann cells, resulting in a decreased axonal organization along with a slowed functional return. In the present work, we investigated the central cellular changes after sciatic nerve injury in rodents treated with A779 after two weeks. In the lumbar spinal cords, where the neuronal bodies that make up the sciatic are, the treatment with A779 showed reduced reactivity of astrocytes (p = 0.004, Mann-Whitney U test) and less synaptic density (p = 0.004, Mann-Whitney U test) after injury. Also, the treatment upregulated microglia activity in both sides (p = 0.004, Mann-Whitney U test), ipsilateral and contralateral to the lesion, of the spinal cord. In addition, the Mas expression in spine neurons was increased in response to axotomy especially after two weeks (p = 0.03, Mann-Whitney U test) following the nerve lesion in comparison to earlier stages after injury. Therefore, we can conclude that Ang-(1-7)/Mas axis plays a role during spinal cord recovery after peripheral nerve injury.

Local angiotensin-(1-7) administration improves microvascular endothelial function in women who have had preeclampsia

Despite remission of clinical symptoms postpartum, women who have had preeclampsia demonstrate microvascular endothelial dysfunction, mediated in part by increased sensitivity to angiotensin II (ANG II). Angiotensin-(1-7) [Ang-(1-7)] is an endogenous inhibitor of the actions of ANG II and plausible druggable target in women who had preeclampsia. We therefore examined the therapeutic potential of Ang-(1-7) in the microvasculature of women with a history of preeclampsia (PrEC; n = 13) and parity-matched healthy control women (HC; n = 13) hypothesizing that administration of Ang-(1-7) would increase endothelium-dependent dilation and nitric oxide (NO)-dependent dilation and decrease ANG II-mediated constriction in PrEC. Using the cutaneous microcirculation, we assessed endothelium-dependent vasodilator function in response to graded infusion of acetylcholine (ACh; 10-7 to 102 mmol/L) in control sites and sites treated with 15 mmol/L NG-nitro-l-arginine methyl ester (l-NAME; NO-synthase inhibitor), 100 µmol/L Ang-(1-7), or 15 mmol/L l-NAME + 100 µmol/L Ang-(1-7). Vasoconstrictor function was measured in response to ANG II (10-20-10-4 mol/L) in control sites and sites treated with 100 µmol/L Ang-(1-7). PrEC had reduced endothelium-dependent dilation (P < 0.001) and NO-dependent dilation (P = 0.04 vs. HC). Ang-(1-7) coinfusion augmented endothelium-dependent dilation (P < 0.01) and NO-dependent dilation (P = 0.03) in PrEC but had no effect in HC. PrEC demonstrated augmented vasoconstrictor responses to ANG II (P < 0.01 vs. HC), which was attenuated by coinfusion of Ang-(1-7) (P < 0.001). Ang-(1-7) increased endothelium-dependent vasodilation via NO synthase-mediated pathways and attenuated ANG II-mediated constriction in women who have had preeclampsia, suggesting that Ang-(1-7) may be a viable therapeutic target for improved microvascular function in women who have had a preeclamptic pregnancy.

Angiotensin-(1-7): Translational Avenues in Cardiovascular Control

Despite decades of research and numerous treatment approaches, hypertension and cardiovascular disease remain leading global public health problems. A major contributor to regulation of blood pressure, and the development of hypertension, is the renin-angiotensin system. Of particular concern, uncontrolled activation of angiotensin II contributes to hypertension and associated cardiovascular risk, with antihypertensive therapies currently available to block the formation and deleterious actions of this hormone. More recently, angiotensin-(1-7) has emerged as a biologically active intermediate of the vasodilatory arm of the renin-angiotensin system. This hormone antagonizes angiotensin II actions as well as offers antihypertensive, antihypertrophic, antiatherogenic, antiarrhythmogenic, antifibrotic and antithrombotic properties. Angiotensin-(1-7) elicits beneficial cardiovascular actions through mas G protein-coupled receptors, which are found in numerous tissues pivotal to control of blood pressure including the brain, heart, kidneys, and vasculature. Despite accumulating evidence for favorable effects of angiotensin-(1-7) in animal models, there is a paucity of clinical studies and pharmacokinetic limitations, thus limiting the development of therapeutic agents to better understand cardiovascular actions of this vasodilatory peptide hormone in humans. This review highlights current knowledge on the role of angiotensin-(1-7) in cardiovascular control, with an emphasis on significant animal, human, and therapeutic research efforts.

Effect of heme oxygenase 1 and renin/prorenin receptor on oxidized low-density lipoprotein-induced human umbilical vein endothelial cells

The incidence of depression has previously been correlated to hypertension. The aim of the present study was to explore the mechanisms of depression and hypertension by examining the expression and interaction of renin/prorenin receptor (PRR) and heme oxygenase 1 (HO-1) in vascular endothelial cells. A case-control study was conducted, and general data and serum factors were compared between hypertension patients complicated with depression and patients with hypertension alone. Logistic regression analysis was used to detect risk factors associated with hypertension complicated with depression. In addition, human umbilical vein endothelial cells (HUVECs) were treated with oxidized low-density lipoprotein (ox-LDL) and/or PRR gene silencing, and a Cell Counting Kit-8 (CCK-8) assay was performed to test their proliferation. The concentrations of inflammatory factors and oxidative stress factor were also detected using enzyme-linked immunosorbent assay and chemical colorimetry. Western blot analysis and reverse transcription-quantitative polymerase chain reaction were applied to detect protein and mRNA expression levels, respectively. The results revealed that HO-1 and renin precursor (Rep) were independent factors that affected hypertension complicated with depression. Serum HO-1 levels in patients with hypertension complicated with depression were significantly lower than that in hypertensive patients without depression, while Rep levels in patients with hypertension complicated with depression were significantly higher than that in hypertensive patients without depression. In HUVECs, ox-LDL reduced the cell proliferation in a dose-dependent manner, upregulated the expression of PRR gene and downregulated the expression of HO-1 gene. It was also observed that silencing of the PRR gene promoted the expression of the HO-1 gene. Furthermore, ox-LDL upregulated the inflammatory response and oxidative stress levels, while PRR gene silencing inhibited the ox-LDL-induced inflammatory factor and oxidative stress levels in HUVECs. Thus, regulating the expression levels of HO-1 and PRR to inhibit the oxidative stress and pro-inflammatory effect of ox-LDL may provide new insight for the treatment of hypertension patients with depression.

RhoA-Rho associated kinase signaling leads to renin-angiotensin system imbalance and angiotensin converting enzyme 2 has a protective role in acute pulmonary embolism

INTRODUCTION

Acute pulmonary embolism (APE) is a cardiovascular disease with high morbidity and mortality. Although the anatomical obstruction of the pulmonary vascular bed initiates APE, recent studies have suggested that vasoconstrictors in the renin-angiotensin system (RAS) play a role in the severity of APE.

MATERIALS AND METHODS

We performed a 5-year retrospective clinical study to analyze the key RAS components in APE patients, including angiotensin converting enzyme (ACE), ACE2, angiotensin II (Ang II) and angiotensin 1-7(Ang(1-7)). The role of RhoA-Rho associated kinase (ROCK) signaling in regulating RAS vasoconstrictors was detected in rat pulmonary artery endothelial cells and in an APE rat model.

RESULTS

In clinical study, we found that the levels of RAS vasoconstrictors were correlated with the clinical classification of APE patients, ACE and Ang II were unregulated, whereas ACE2 and Ang(1-7) were downregulated in the high-risk group compared to the healthy volunteers. In animal study, we found that activated RhoA-ROCK signaling was responsible for the imbalance in RAS vasoconstrictors both in vitro and in vivo, and further evidence indicated that ROCK inhibitors (Y27632 or HA1077) and an ACE2 activator (Resorcinol naphthalein) restored the dysregulated RAS vasoconstrictors significantly and had a protective role in an APE rat model.

CONCLUSIONS

Our study revealed that RhoA-ROCK signaling leads to RAS imbalance in APE patients, and ACE2 activation might be a novel therapeutic target in APE treatment.

Effects of angiotensin-(1-7) and angiotensin II on vascular tone in human cirrhotic splanchnic vessels

Evidence suggests that the renin angiotensin system (RAS) may play a role in the pathological splanchnic vasodilatation that leads to a hyperdynamic circulation in cirrhosis. An impaired contractile response to the angiotensin II peptide of the classical RAS system has been described in animal models of cirrhosis and in vivo in cirrhotic subjects. Furthermore, in experimental cirrhosis, the so-called alternate arm of the RAS was found to be upregulated and its effector peptide, angiotensin-(1-7) was shown to attenuate splanchnic vascular tone. The aim of this study was to explore the relevance of these findings to human disease. Omental arteries from cirrhotic and controls subjects were studied in isolation using a wire myograph. Varied protocols to evaluate the vasoactivity of RAS mediators were enacted. The contractile response to angiotensin II was comparable in cirrhotic vs control splanchnic arteries (61 ± 9 vs 68 ± 11% KPSS, respectively). Despite this, however, arterial contractility of the cirrhotic vessels correlated negatively with Child Pugh score (p = 0.0003, r=-0.83) and there was evidence that angiotensin II-induced contractility was increased in early cirrhosis. Angiotensin II-induced contractility was attenuated by angiotensin-(1-7) in cirrhotic and control arteries, however, adrenergic responses were not affected by angiotensin-(1-7). Contractile responses to angiotensin II are preserved in narrow lumen human cirrhotic splanchnic arteries and are comparatively augmented in early disease. Angiotensin-(1-7) had no vasodilatory effect on adrenergic tone, however, attenuated angiotensin II-induced contractility, possibly through an Ang-(1-7)-AT1R interaction, and thus may contribute to pathological vasodilatation in human cirrhosis.

The ACE2/Angiotensin-(1-7)/MAS Axis of the Renin-Angiotensin System: Focus on Angiotensin-(1-7)

The renin-angiotensin system (RAS) is a key player in the control of the cardiovascular system and hydroelectrolyte balance, with an influence on organs and functions throughout the body. The classical view of this system saw it as a sequence of many enzymatic steps that culminate in the production of a single biologically active metabolite, the octapeptide angiotensin (ANG) II, by the angiotensin converting enzyme (ACE). The past two decades have revealed new functions for some of the intermediate products, beyond their roles as substrates along the classical route. They may be processed in alternative ways by enzymes such as the ACE homolog ACE2. One effect is to establish a second axis through ACE2/ANG-(1-7)/MAS, whose end point is the metabolite ANG-(1-7). ACE2 and other enzymes can form ANG-(1-7) directly or indirectly from either the decapeptide ANG I or from ANG II. In many cases, this second axis appears to counteract or modulate the effects of the classical axis. ANG-(1-7) itself acts on the receptor MAS to influence a range of mechanisms in the heart, kidney, brain, and other tissues. This review highlights the current knowledge about the roles of ANG-(1-7) in physiology and disease, with particular emphasis on the brain.

Genetic Interference With Endothelial PPAR-γ (Peroxisome Proliferator-Activated Receptor-γ) Augments Effects of Angiotensin II While Impairing Responses to Angiotensin 1-7

Pharmacological activation of PPAR-γ (peroxisome proliferator-activated receptor-γ) protects the vasculature. Much less is known on the cell-specific impact of PPAR-γ when driven by endogenous ligands. Recently, we found that endothelial PPAR-γ protects against angiotensin II-induced endothelial dysfunction. Here, we explored that concept further examining whether effects were sex dependent along with underlying mechanisms. We studied mice expressing a human dominant-negative mutation in PPAR-γ driven by the endothelial-specific vascular cadherin promoter (E-V290M), using nontransgenic littermates as controls. Acetylcholine (an endothelium-dependent agonist) produced similar relaxation of carotid arteries from nontransgenic and E-V290M mice. Incubation of isolated arteries with angiotensin II (1 nmol/L) overnight had no effect in nontransgenic, but reduced responses to acetylcholine by about 50% in male and female E-V290M mice (P<0.05). Endothelial function in E-V290M mice was restored to normal by inhibitors of superoxide (tempol), NADPH oxidase (VAS-2870), Rho kinase (Y-27632), ROCK2 (SLX-2119), NF-κB (nuclear factor-kappa B essential modulator-binding domain peptide), or interleukin-6 (neutralizing antibody). In addition, we hypothesized that PPAR-γ may influence the angiotensin 1-7 arm of the renin-angiotensin system. In the basilar artery, dilation to angiotensin 1-7 was selectively reduced in E-V290M mice by >50% (P<0.05), an effect reversed by Y-27632. Thus, effects of angiotensin II are augmented by interference with endothelial PPAR-γ through sex-independent mechanisms, involving oxidant-inflammatory signaling and ROCK2 (Rho kinase). The study also provides the first evidence that endothelial PPAR-γ interacts with angiotensin 1-7 responses. These critical roles for endothelial PPAR-γ have implications for pathophysiology and therapeutic approaches for vascular disease.

Significance of angiotensin 1-7 coupling with MAS1 receptor and other GPCRs to the renin-angiotensin system: IUPHAR Review 22

Angiotensins are a group of hormonal peptides and include angiotensin II and angiotensin 1-7 produced by the renin angiotensin system. The biology, pharmacology and biochemistry of the receptors for angiotensins were extensively reviewed recently. In the review, the receptor nomenclature committee was not emphatic on designating MAS1 as the angiotensin 1-7 receptor on the basis of lack of classical G protein signalling and desensitization in response to angiotensin 1-7, as well as a lack of consensus on confirmatory ligand pharmacological analyses. A review of recent publications (2013-2016) on the rapidly progressing research on angiotensin 1-7 revealed that MAS1 and two additional receptors can function as 'angiotensin 1-7 receptors', and this deserves further consideration. In this review we have summarized the information on angiotensin 1-7 receptors and their crosstalk with classical angiotensin II receptors in the context of the functions of the renin angiotensin system. It was concluded that the receptors for angiotensin II and angiotensin 1-7 make up a sophisticated cross-regulated signalling network that modulates the endogenous protective and pathogenic facets of the renin angiotensin system.

Angiotensin-(1–7) attenuates angiotensin II-induced cardiac hypertrophy via a Sirt3-dependent mechanism

The objectives of the present study were to investigate the effect of ANG-(1–7) on the development of cardiac hypertrophy and to identify the intracellular mechanism underlying this action of ANG-(1–7). Blood pressure and heart rate were recorded using radiotelemetry before and after chronic subcutaneous infusion of control (PBS), ANG II, ANG-(1–7), or ANG II + ANG-(1–7) for 4 wk in normotensive rats. Chronic administration of ANG-(1–7) did not affect either basal blood pressure or the ANG II-induced elevation in blood pressure. However, ANG-(1–7) significantly attenuated ANG II-induced cardiac hypertrophy and perivascular fibrosis in these rats. These effects of ANG-(1–7) were confirmed in cultured cardiomyocytes, in which ANG-(1–7) significantly attenuated ANG II-induced increases in cell size. This protective effect of ANG-(1–7) was significantly attenuated by pretreatment with A779 (a Mas receptor antagonist) or Mito-TEMPO (a mitochondria-targeting superoxide scavenger) as well as blockade of Sirt3 (a deacetylation-acting protein) by viral vector-mediated overexpression of sirtuin (Sirt)3 short hairpin (sh)RNA. Western blot analysis demonstrated that treatment with ANG-(1–7) dramatically increased Sirt3 expression. In addition, ANG-(1–7) attenuated the ANG II-induced increase in mitochondrial ROS generation, an effect that was abolished by A779 or Sirt3 shRNA. Moreover, ANG-(1–7) increased FoxO3a deacetylation and SOD2 expression, and these effects were blocked by Sirt3 shRNA. In summary, the protective effects of ANG-(1–7) on ANG II-induced cardiac hypertrophy and increased mitochondrial ROS production are mediated by elevated SOD2 expression via stimulation of Sirt3-dependent deacetylation of FoxO3a in cardiomyocytes. Thus, activation of the ANG-(1–7)/Sirt3 signaling pathway could be a novel therapeutic strategy in the management of cardiac hypertrophy and associated complications.

NEW & NOTEWORTHY Chronic subcutaneous ANG-(1–7) has no effect on ANG II-induced elevations in blood pressure but significantly attenuates ANG II-induced cardiac hypertrophy and fibrosis by a mitochondrial ROS-dependent mechanism. This protective effect of ANG-(1–7) against the action of ANG II action is mediated by stimulation of sirtuin-3-mediated deacetylation of FoxO3a, which triggers SOD2 expression.

Association between angiotensinogen T174M polymorphism and ischemic stroke: A meta-analysis

BACKGROUND

Numerous studies have evaluated the association between the angiotensinogen (AGT) T174M polymorphism and ischemic stroke(IS) risk. However, the specific association is still controversial.

MATERIALS AND METHODS

In order to explore this association more deeply, we performed a meta-analysis. All of the relevant studies were identified from PubMed, Embase, and Chinese National Knowledge Infrastructure database up to October 2014. Statistical analyses were conducted with STATA 12.0 software. Odds ratio (OR) with 95% confidence interval (CI) values were applied to evaluate the strength of the association.

RESULTS

Six studies with 1290 cases and 1125 controls were included. No significant variation in IS risk was detected in any of the genetic models in the overall (MM vs. TT: OR = 1.64, 95% CI = 0.51-5.28; MT vs. TT: OR = 0.93, 95% CI = 0.66-1.31; dominant model: OR = 1.08, 95% CI = 0.69-1.72; recessive model: OR = 0.61,95% CI = 0.20-1.91). Taking into account the effect of ethnicity, further stratified analyses were performed. The results showed that AGT gene T174M polymorphism might be associated with IS risk in Asians (MM vs. TT: OR = 3.28, 95% CI = 1.79-6.02; recessive model: OR = 0.31, 95% CI = 0.17-0.57).

CONCLUSION

In conclusion, the AGT T174M polymorphism may be a susceptible predictor of the risk of IS in Asians. Further, large and well-designed studies are needed to confirm this conclusion.