Impact of vessel size on angiographic and clinical outcomes of revascularization with biolimus-eluting stent with biodegradable polymer and sirolimus-eluting stent with durable polymer the LEADERS trial substudy

OBJECTIVES: We assessed the impact of vessel size on outcomes of stenting with biolimus-eluting degradable polymer stent (BES) and sirolimus-eluting permanent polymer stent (SES) within a randomized multicenter trial (LEADERS). BACKGROUND: Stenting of small vessels might be associated with higher rates of adverse events. METHODS: "All-comer" patients (n = 1,707) were randomized to BES and SES. Post-hoc-stratified analysis of angiographic and clinical outcomes at 9 months and 1 year, respectively, was performed for vessels with reference diameter 2.75 mm. RESULTS: Of 1,707 patients, 429 patients in the BES group with 576 lesions and 434 patients in the SES group with 557 lesions had only small vessels treated (50.6% of the patient cohort). In patients with small vessels there was no significant difference in overall major adverse cardiac events (MACE) rate (12.1% vs. 11.8%; p = 0.89) or target lesion revascularization (TLR) rate (9.6% vs. 7.4%; p = 0.26) between BES and SES. The MACE and TLR rates in the small-vessel patient population were higher than in the large-vessel population. The TLR rate was 9.6% versus 2.6%, and MACE rate was 12.1% versus 7.1% for small versus large vessels in the BES arm (TLR: hazard ratio [HR] = 3.724, p = 0.0013; MACE: HR = 1.720, p = 0.0412). In the SES arm, TLR was 7.4% versus 5.1%, and MACE was 11.8% versus 10.3% in small versus large vessels (TLR: HR = 1.435, p = 0.2594; MACE: HR = 1.149, p = 0.5546). CONCLUSIONS: Prevalence of small vessel disease is high in an "all-comer" population with higher TLR and MACE rates. The BES and SES seem equivalent in treatment outcomes of small vessels in this "all-comer" patient population.

Biolimus-eluting biodegradable polymer versus sirolimus-eluting permanent polymer stent performance in long lesions: results from the LEADERS multicentre trial substudy

AIMS: Lesion length remains a predictor of target lesion revascularisation and results of long lesion stenting remain poor. Sirolimus-eluting stents have been shown to perform better than paclitaxel eluting stents in long lesions. In this substudy of the LEADERS trial, we compared the performance of biolimus biodegradable polymer (BES) and sirolimus permanent polymer stents (SES) in long lesions. METHODS AND RESULTS: A total of 1,707 'all-comer' patients were randomly allocated to treatment with BES and SES. A stratified analysis of angiographic and clinical outcomes at nine months and one year, respectively was performed for vessels with lesion length <20 mm versus >20 mm (as measured by quantitative angiography).Of 1,707 patients, 592 BES patients with 831 lesions and 619 SES patients with 876 lesions had only short lesions treated. One hundred and fifty-three BES patients with 166 lesions and 151 SES patients with 162 lesions had long lesions. There were no significant differences in baseline clinical characteristics, except for higher number of patients with long lesions presenting with acute myocardial infarction in both stent groups. Long lesions tended to have lower MLD and greater percent diameter stenosis at baseline than short lesions. Late loss was greater for long lesions than short lesions. There was no statistically significant difference in late loss between BES and SES stents (0.32+/-0.69 vs 0.24+/-0.57, p=0.59). Binary in-segment restenosis was present in 23.2% versus 13.1% of long lesions treated with BES and SES, respectively (p=0.042). In patients with long lesions, the overall MACE rate was similar for BES and SES (17% vs 14.6%; p=0.62). There was a trend towards higher overall TLR rate with BES (12.4 % vs 6.0%; HR=2.06; p=0.07) and clinically driven TLR (10.5% vs 5.3%: HR 1.94; p=0.13). Rates of definite stent thrombosis were 3.3% in the long lesion group and 1.3-1.7 % in the short lesion group. CONCLUSIONS: BES and SES appear similar with respect to MACE in long lesions in this "all-comer" patient population. However, long lesions tended to have a higher rate of binary in-segment restenosis and TLR following BES than SES treatment.

Unprotected left main stenting in the real world: two-year outcomes of the French left main taxus registry

BACKGROUND: Cardiac surgery is the reference treatment for patients with left main (LM) disease, although percutaneous coronary intervention with drug-eluting stents is emerging as a possible alternative. The objective of this registry was to evaluate the 2-year outcome of elective percutaneous coronary intervention for unprotected LM disease with paclitaxel-eluting stents. METHODS AND RESULTS: A total of 291 patients were prospectively included from 4 centers. Acute myocardial infarction and cardiogenic shock were the only exclusion criteria. Patients were 69+/-11 years old, 29% were diabetic, and 25% had 3-vessel disease. For distal LM lesions (78%), the provisional side-branch T-stenting approach was used in 92% of cases and final kissing balloon inflation in 97%. Angiographic success was obtained in 99.7% of cases. At 2-year follow-up, the total cardiac death rate was 5.4% (1 EuroSCORE point was associated with a 15% [95% confidence interval 2.9% to 28.2%, P=0.013] higher risk of cardiac death), target-lesion revascularization was 8.7%, and incidence of Q-wave or non-Q-wave myocardial infarction was 0.9% and 3.1%, respectively. The combined end point occurred in 15.8% of cases and stroke in 0.7%. The incidence of definite and probable LM stent thrombosis was 0.7%, whereas the incidence of any stent thrombosis was 3.8%, with a higher risk in patients with side-branch stenting in the presence of LM bifurcation lesions (hazard ratio 9.6, 95% confidence interval 1.2 to 77.7, P=0.035). CONCLUSIONS: Unprotected LM stenting with paclitaxel-eluting stents, with a strategy of provisional side-branch T-stenting for distal lesions, provides excellent acute angiographic results and good mid-term clinical outcomes, with a 15.8% rate of major adverse cardiac events at 2-year follow-up.

Quantitative sequence analysis of FBN1 premature termination codons provides evidence for incomplete NMD in leukocytes

We improved, evaluated, and used Sanger sequencing for quantification of single nucleotide polymorphism (SNP) variants in transcripts and gDNA samples. This improved assay resulted in highly reproducible relative allele frequencies (e.g., for a heterozygous gDNA 50.0+/-1.4%, and for a missense mutation-bearing transcript 46.9+/-3.7%) with a lower detection limit of 3-9%. It provided excellent accuracy and linear correlation between expected and observed relative allele frequencies. This sequencing assay, which can also be used for the quantification of copy number variations (CNVs), methylations, mosaicisms, and DNA pools, enabled us to analyze transcripts of the FBN1 gene in fibroblasts and blood samples of patients with suspected Marfan syndrome not only qualitatively but also quantitatively. We report a total of 18 novel and 19 known FBN1 sequence variants leading to a premature termination codon (PTC), 26 of which we analyzed by quantitative sequencing both at gDNA and cDNA levels. The relative amounts of PTC-containing FBN1 transcripts in fresh and PAXgene-stabilized blood samples were significantly higher (33.0+/-3.9% to 80.0+/-7.2%) than those detected in affected fibroblasts with inhibition of nonsense-mediated mRNA decay (NMD) (11.0+/-2.1% to 25.0+/-1.8%), whereas in fibroblasts without NMD inhibition no mutant alleles could be detected. These results provide evidence for incomplete NMD in leukocytes and have particular importance for RNA-based analyses not only in FBN1 but also in other genes.

Improved safety and reduction in stent thrombosis associated with biodegradable polymer-based biolimus-eluting stents versus durable polymer-based sirolimus-eluting stents in patients with coronary artery disease: final 5-year report of the LEADERS (Limus Eluted From A Durable Versus ERodable Stent Coating) randomized, noninferiority trial

OBJECTIVES This study sought to report the final 5 years follow-up of the landmark LEADERS (Limus Eluted From A Durable Versus ERodable Stent Coating) trial. BACKGROUND The LEADERS trial is the first randomized study to evaluate biodegradable polymer-based drug-eluting stents (DES) against durable polymer DES. METHODS The LEADERS trial was a 10-center, assessor-blind, noninferiority, "all-comers" trial (N = 1,707). All patients were centrally randomized to treatment with either biodegradable polymer biolimus-eluting stents (BES) (n = 857) or durable polymer sirolimus-eluting stents (SES) (n = 850). The primary endpoint was a composite of cardiac death, myocardial infarction (MI), or clinically indicated target vessel revascularization within 9 months. Secondary endpoints included extending the primary endpoint to 5 years and stent thrombosis (ST) (Academic Research Consortium definition). Analysis was by intention to treat. RESULTS At 5 years, the BES was noninferior to SES for the primary endpoint (186 [22.3%] vs. 216 [26.1%], rate ratio [RR]: 0.83 [95% confidence interval (CI): 0.68 to 1.02], p for noninferiority <0.0001, p for superiority = 0.069). The BES was associated with a significant reduction in the more comprehensive patient-orientated composite endpoint of all-cause death, any MI, and all-cause revascularization (297 [35.1%] vs. 339 [40.4%], RR: 0.84 [95% CI: 0.71 to 0.98], p for superiority = 0.023). A significant reduction in very late definite ST from 1 to 5 years was evident with the BES (n = 5 [0.7%] vs. n = 19 [2.5%], RR: 0.26 [95% CI: 0.10 to 0.68], p = 0.003), corresponding to a significant reduction in ST-associated clinical events (primary endpoint) over the same time period (n = 3 of 749 vs. n = 14 of 738, RR: 0.20 [95% CI: 0.06 to 0.71], p = 0.005). CONCLUSIONS The safety benefit of the biodegradable polymer BES, compared with the durable polymer SES, was related to a significant reduction in very late ST (>1 year) and associated composite clinical outcomes. (Limus Eluted From A Durable Versus ERodable Stent Coating [LEADERS] trial; NCT00389220).

Safety and efficacy of drug-eluting stents in women: a patient-level pooled analysis of randomised trials

BACKGROUND The safety and efficacy of drug-eluting stents (DES) in the treatment of coronary artery disease have been assessed in several randomised trials. However, none of these trials were powered to assess the safety and efficacy of DES in women because only a small proportion of recruited participants were women. We therefore investigated the safety and efficacy of DES in female patients during long-term follow-up. METHODS We pooled patient-level data for female participants from 26 randomised trials of DES and analysed outcomes according to stent type (bare-metal stents, early-generation DES, and newer-generation DES). The primary safety endpoint was a composite of death or myocardial infarction. The secondary safety endpoint was definite or probable stent thrombosis. The primary efficacy endpoint was target-lesion revascularisation. Analysis was by intention to treat. FINDINGS Of 43,904 patients recruited in 26 trials of DES, 11,557 (26·3%) were women (mean age 67·1 years [SD 10·6]). 1108 (9·6%) women received bare-metal stents, 4171 (36·1%) early-generation DES, and 6278 (54·3%) newer-generation DES. At 3 years, estimated cumulative incidence of the composite of death or myocardial infarction occurred in 132 (12·8%) women in the bare-metal stent group, 421 (10·9%) in the early-generation DES group, and 496 (9·2%) in the newer-generation DES group (p=0·001). Definite or probable stent thrombosis occurred in 13 (1·3%), 79 (2·1%), and 66 (1·1%) women in the bare-metal stent, early-generation DES, and newer-generation DES groups, respectively (p=0·01). The use of DES was associated with a significant reduction in the 3 year rates of target-lesion revascularisation (197 [18·6%] women in the bare-metal stent group, 294 [7·8%] in the early-generation DES group, and 330 [6·3%] in the newer-generation DES group, p<0·0001). Results did not change after adjustment for baseline characteristics in the multivariable analysis. INTERPRETATION The use of DES in women is more effective and safe than is use of bare-metal stents during long-term follow-up. Newer-generation DES are associated with an improved safety profile compared with early-generation DES, and should therefore be thought of as the standard of care for percutaneous coronary revascularisation in women. FUNDING Women in Innovation Initiative of the Society of Cardiovascular Angiography and Interventions.

Biolimus-eluting stent with biodegradable polymer improves clinical outcomes in patients with acute myocardial infarction

OBJECTIVE To investigate clinical outcomes of coronary intervention using a biolimus-eluting stent (BES) compared with a sirolimus-eluting stent (SES) in patients with acute myocardial infarction (AMI) in the Limus Eluted from A Durable versus ERodable Stent (LEADERS) coating trial at the final 5-year follow-up. METHODS The LEADERS trial is a multicentre all-comer study, where patients (n=1707) were randomised to percutaneous intervention with either BES containing biodegradable polymer or SES containing durable polymer. Out of 1707 patients enrolled in this trial, 573 patients had percutaneous coronary intervention for AMI (BES=280, SES=293) and were included in the current analysis. Patient-oriented composite endpoint (POCE, including all death, all myocardial infarction (MI) and all revascularisations), major adverse cardiac events (MACE, including cardiac death, MI and clinically indicated target vessel revascularisation) and stent thrombosis were assessed at 5-year follow-up. RESULTS The baseline clinical, angiographic and procedural characteristics were well matched between BES and SES groups. In all patients with AMI, coronary intervention with a BES, compared with SES, significantly reduced POCE (28.9% vs 42.3%; relative risk (RR) 0.61, 95% CI 0.47 to 0.82, p=0.001) at 5-year follow-up. There was also a reduction in MACE rate in the BES group (18.2% vs 25.9%; RR 0.67, 95% CI 0.47 to 0.95, p=0.025); however, there was no difference in cardiac death and stent thrombosis. In patients with ST-elevation MI (STEMI), coronary intervention with BES significantly reduced POCE (24.4% vs 39.3%; RR 0.55, 95% CI 0.36 to 0.85, p=0.006), MACE (12.6% vs 25.0%; RR 0.47, 95% CI 0.26 to 0.83, p=0.008) and cardiac death (3.0% vs 11.4%; RR 0.25, 95% CI 0.08 to 0.75, p=0.007), along with a trend towards reduction in definite stent thrombosis (3.7% vs 8.6%; RR 0.41, 95% CI 0.15 to 1.18, p=0.088), compared with SES. CONCLUSIONS BES, compared with SES, significantly improved safety and efficacy outcomes in patients with AMI, especially those with STEMI, at 5-year follow-up. TRIAL REGISTRATION NUMBER NCT 00389220.

Unmet needs of young interventional cardiologists: proceedings from the 2nd summit of the European association of percutaneous cardiovascular interventions

Every year, the EAPCI Board invites presidents and representatives of the interventional working groups affiliated to EAPCI to discuss issues and strategies surrounding the goals of education and advanced healthcare practices in interventional cardiology. In 2013, the 2nd EAPCI Summit, organised by the EAPCI Board in collaboration with the NIFYI committee, was entirely dedicated to discussing the unmet needs of the young generation of interventional cardiologists. In this article, we highlight a selection of the key points and proposed actions highlighted during the summit.

First generation versus second generation drug-eluting stents for the treatment of bifurcations: 5-year follow-up of the LEADERS all-comers randomized trial.

BACKGROUND Historically, percutaneous coronary intervention (PCI) of bifurcation lesions was associated with worse procedural and clinical outcomes when compared with PCI of non-bifurcation lesions. Newer generation drug-eluting stents (DES) might improve long-term clinical outcomes after bifurcation PCI. METHODS AND RESULTS The LEADERS trial was a 10-center, assessor-blind, non-inferiority, all-comers trial, randomizing 1,707 patients to treatment with a biolimus A9(TM) -eluting stent (BES) with an abluminal biodegradable polymer or a sirolimus-eluting stent (SES) with a durable polymer (ClinicalTrials.gov Identifier: NCT00389220). Five-year clinical outcomes were compared between patients with and without bifurcation lesions and between BES and SES in the bifurcation lesion subgroup. There were 497 (29%) patients with at least 1 bifurcation lesion (BES = 258; SES = 239). At 5-year follow-up, the composite endpoint of cardiac death, myocardial infarction (MI) and clinically-indicated (CI) target vessel revascularization (TVR) was observed more frequently in the bifurcation group (26.6% vs. 22.4%, P = 0.049). Within the bifurcation lesion subgroup, no differences were observed in (cardiac) death or MI rates between BES and SES. However, CI target lesion revascularization (TLR) (10.1% vs. 15.9%, P = 0.0495), and CI TVR (12.0% vs. 19.2%, P = 0.023) rates were significantly lower in the BES group. Definite/probable stent thrombosis (ST) rate was numerically lower in the BES group (3.1% vs. 5.9%, P = 0.15). Very late (>1 year) definite/probable ST rates trended to be lower with BES (0.4% vs. 3.1%, P = 0.057). CONCLUSIONS In the treatment of bifurcation lesions, use of BES led to superior long-term efficacy compared with SES. Safety outcomes were comparable between BES and SES, with an observed trend toward a lower rate of very late definite/probable ST between 1 and 5 years with the BES. © 2015 Wiley Periodicals, Inc.

Impact of Clinical Presentation (Stable Angina Pectoris vs Unstable Angina Pectoris or Non-ST-Elevation Myocardial Infarction vs ST-Elevation Myocardial Infarction) on Long-Term Outcomes in Women Undergoing Percutaneous Coronary Intervention With Drug-Eluting Stents

The long-term risk associated with different coronary artery disease (CAD) presentations in women undergoing percutaneous coronary intervention (PCI) with drug-eluting stents (DES) is poorly characterized. We pooled patient-level data for women enrolled in 26 randomized clinical trials. Of 11,577 women included in the pooled database, 10,133 with known clinical presentation received a DES. Of them, 5,760 (57%) had stable angina pectoris (SAP), 3,594 (35%) had unstable angina pectoris (UAP) or non-ST-segment-elevation myocardial infarction (NSTEMI), and 779 (8%) had ST-segment-elevation myocardial infarction (STEMI) as clinical presentation. A stepwise increase in 3-year crude cumulative mortality was observed in the transition from SAP to STEMI (4.9% vs 6.1% vs 9.4%; p <0.01). Conversely, no differences in crude mortality rates were observed between 1 and 3 years across clinical presentations. After multivariable adjustment, STEMI was independently associated with greater risk of 3-year mortality (hazard ratio [HR] 3.45; 95% confidence interval [CI] 1.99 to 5.98; p <0.01), whereas no differences were observed between UAP or NSTEMI and SAP (HR 0.99; 95% CI 0.73 to 1.34; p = 0.94). In women with ACS, use of new-generation DES was associated with reduced risk of major adverse cardiac events (HR 0.58; 95% CI 0.34 to 0.98). The magnitude and direction of the effect with new-generation DES was uniform between women with or without ACS (pinteraction = 0.66). In conclusion, in women across the clinical spectrum of CAD, STEMI was associated with a greater risk of long-term mortality. Conversely, the adjusted risk of mortality between UAP or NSTEMI and SAP was similar. New-generation DESs provide improved long-term clinical outcomes irrespective of the clinical presentation in women.

Effect of Chronic Kidney Disease in Women Undergoing Percutaneous Coronary Intervention With Drug-Eluting Stents: A Patient-Level Pooled Analysis of Randomized Controlled Trials.

OBJECTIVES This study sought to evaluate: 1) the effect of impaired renal function on long-term clinical outcomes in women undergoing percutaneous coronary intervention (PCI) with drug-eluting stent (DES); and 2) the safety and efficacy of new-generation compared with early-generation DES in women with chronic kidney disease (CKD). BACKGROUND The prevalence and effect of CKD in women undergoing PCI with DES is unclear. METHODS We pooled patient-level data for women enrolled in 26 randomized trials. The study population was categorized by creatinine clearance (CrCl) <45 ml/min, 45 to 59 ml/min, and ≥60 ml/min. The primary endpoint was the 3-year rate of major adverse cardiovascular events (MACE). Participants for whom baseline creatinine was missing were excluded from the analysis. RESULTS Of 4,217 women included in the pooled cohort treated with DES and for whom serum creatinine was available, 603 (14%) had a CrCl <45 ml/min, 811 (19%) had a CrCl 45 to 59 ml/min, and 2,803 (66%) had a CrCl ≥60 ml/min. A significant stepwise gradient in risk for MACE was observed with worsening renal function (26.6% vs. 15.8% vs. 12.9%; p < 0.01). Following multivariable adjustment, CrCl <45 ml/min was independently associated with a higher risk of MACE (adjusted hazard ratio: 1.56; 95% confidence interval: 1.23 to 1.98) and all-cause mortality (adjusted hazard ratio: 2.67; 95% confidence interval: 1.85 to 3.85). Compared with older-generation DES, the use of newer-generation DES was associated with a reduction in the risk of cardiac death, myocardial infarction, or stent thrombosis in women with CKD. The effect of new-generation DES on outcomes was uniform, between women with or without CKD, without evidence of interaction. CONCLUSIONS Among women undergoing PCI with DES, CKD is a common comorbidity associated with a strong and independent risk for MACE that is durable over 3 years. The benefits of newer-generation DES are uniform in women with or without CKD.

Safety and Efficacy of New-Generation Drug-Eluting Stents in Women at High Risk for Atherothrombosis: From the Women in Innovation and Drug-Eluting Stents Collaborative Patient-Level Pooled Analysis

BACKGROUND The safety and efficacy of new-generation drug-eluting stents (DES) in women with multiple atherothrombotic risk (ATR) factors is unclear. METHODS AND RESULTS We pooled patient-level data for women enrolled in 26 randomized trials. Study population was categorized based on the presence or absence of high ATR, which was defined as having history of diabetes mellitus, prior percutaneous or surgical coronary revascularization, or prior myocardial infarction. The primary end point was major adverse cardiovascular events defined as a composite of all-cause mortality, myocardial infarction, or target lesion revascularization at 3 years of follow-up. Out of 10 449 women included in the pooled database, 5333 (51%) were at high ATR. Compared with women not at high ATR, those at high ATR had significantly higher risk of major adverse cardiovascular events (15.8% versus 10.6%; adjusted hazard ratio: 1.53; 95% confidence interval: 1.34-1.75; P=0.006) and all-cause mortality. In high-ATR risk women, the use of new-generation DES was associated with significantly lower risk of 3-year major adverse cardiovascular events (adjusted hazard ratio: 0.69; 95% confidence interval: 0.52-0.92) compared with early-generation DES. The benefit of new-generation DES on major adverse cardiovascular events was uniform between high-ATR and non-high-ATR women, without evidence of interaction (Pinteraction=0.14). At landmark analysis, in high-ATR women, stent thrombosis rates were comparable between DES generations in the first year, whereas between 1 and 3 years, stent thrombosis risk was lower with new-generation devices. CONCLUSIONS Use of new-generation DES even in women at high ATR is associated with a benefit consistent over 3 years of follow-up and a substantial improvement in very-late thrombotic safety.

The Bacillus subtilis crh gene encodes a HPr-like protein involved in carbon catabolite repression

Carbon catabolite repression (CCR) of several Bacillus subtilis catabolic genes is mediated by ATP-dependent phosphorylation of histidine-containing protein (HPr), a phosphocarrier protein of the phosphoenolpyruvate (PEP): sugar phosphotransferase system. In this study, we report the discovery of a new B. subtilis gene encoding a HPr-like protein, Crh (for catabolite repression HPr), composed of 85 amino acids. Crh exhibits 45% sequence identity with HPr, but the active site His-15 of HPr is replaced with a glutamine in Crh. Crh is therefore not phosphorylated by PEP and enzyme I, but is phosphorylated by ATP and the HPr kinase in the presence of fructose-1,6-bisphosphate. We determined Ser-46 as the site of phosphorylation in Crh by carrying out mass spectrometry with peptides obtained by tryptic digestion or CNBr cleavage. In a B. subtilis ptsH1 mutant strain, synthesis of β-xylosidase, inositol dehydrogenase, and levanase was only partially relieved from CCR. Additional disruption of the crh gene caused almost complete relief from CCR. In a ptsH1 crh1 mutant, producing HPr and Crh in which Ser-46 is replaced with a nonphosphorylatable alanyl residue, expression of β-xylosidase was also completely relieved from glucose repression. These results suggest that CCR of certain catabolic operons requires, in addition to CcpA, ATP-dependent phosphorylation of Crh, and HPr at Ser-46.

Aminopeptidase A inhibitors as potential central antihypertensive agents

Overactivity of the brain renin-angiotensin system (RAS) has been implicated in the development and maintenance of hypertension in several experimental models, such as spontaneously hypertensive rats and transgenic mice expressing both human renin and human angiotensinogen transgenes. We recently reported that, in the murine brain, angiotensin II (AngII) is converted to angiotensin III (AngIII) by aminopeptidase A (APA), whereas AngIII is inactivated by aminopeptidase N (APN). If injected into cerebral ventricles (ICV), AngII and AngIII cause similar pressor responses. Because AngII is metabolized in vivo into AngIII, the exact nature of the active peptide is not precisely determined. Here we report that, in rats, ICV injection of the selective APA inhibitor EC33 [(S)-3-amino-4-mercaptobutyl sulfonic acid] blocked the pressor response of exogenous AngII, suggesting that the conversion of AngII to AngIII is required to increase blood pressure (BP). Furthermore, ICV injection, but not i.v. injection, of EC33 alone caused a dose-dependent decrease in BP by blocking the formation of brain but not systemic AngIII. This is corroborated by the fact that the selective APN inhibitor, PC18 (2-amino-4-methylsulfonyl butane thiol), administered alone via the ICV route, increases BP. This pressor response was blocked by prior treatment with the angiotensin type 1 (AT1) receptor antagonist, losartan, showing that blocking the action of APN on AngIII metabolism leads to an increase in endogenous AngIII levels, resulting in BP increase, through interaction with AT1 receptors. These data demonstrate that AngIII is a major effector peptide of the brain RAS, exerting tonic stimulatory control over BP. Thus, APA, the enzyme responsible for the formation of brain AngIII, represents a potential central therapeutic target that justifies the development of APA inhibitors as central antihypertensive agents.