Rafael Cavalcante

Clinical outcomes of state-of-the-art percutaneous coronary revascularization in patients with de novo three vessel disease: 1-year results of the SYNTAX II study.

Abstract Aims To investigate if recent technical and procedural developments in percutaneous coronary intervention (PCI) significantly influence outcomes in appropriately selected patients with three-vessel (3VD) coronary artery disease. Methods and results The SYNTAX II study is a multicenter, all-comers, open-label, single arm study that investigated the impact of a contemporary PCI strategy on clinical outcomes in patients with 3VD in 22 centres from four European countries. The SYNTAX-II strategy includes: heart team decision-making utilizing the SYNTAX Score II (a clinical tool combining anatomical and clinical factors), coronary physiology guided revascularisation, implantation of thin strut bioresorbable-polymer drug-eluting stents, intravascular ultrasound (IVUS) guided stent implantation, contemporary chronic total occlusion revascularisation techniques and guideline-directed medical therapy. The rate of major adverse cardiac and cerebrovascular events (MACCE [composite of all-cause death, cerebrovascular event, any myocardial infarction and any revascularisation]) at one year was compared to a predefined PCI cohort from the original SYNTAX-I trial selected on the basis of equipoise 4-year mortality between CABG and PCI. As an exploratory endpoint, comparisons were made with the historical CABG cohort of the original SYNTAX-I trial. Overall 708 patients were screened and discussed within the heart team; 454 patients were deemed appropriate to undergo PCI. At one year, the SYNTAX-II strategy was superior to the equipoise-derived SYNTAX-I PCI cohort (MACCE SYNTAX-II 10.6% vs. SYNTAX-I 17.4%; HR 0.58, 95% CI 0.39–0.85, P = 0.006). This difference was driven by a significant reduction in the incidence of MI (HR 0.27, 95% CI 0.11–0.70, P = 0.007) and revascularisation (HR 0.57, 95% CI 0.37–0.9, P = 0.015). Rates of all-cause death (HR 0.69, 95% CI 0.27–1.73, P = 0.43) and stroke (HR 0.69, 95% CI 0.10–4.89, P = 0.71) were similar. The rate of definite stent thrombosis was significantly lower in SYNTAX-II (HR 0.26, 95% CI 0.07–0.97, P = 0.045). Conclusion At one year, clinical outcomes with the SYNTAX-II strategy were associated with improved clinical results compared to the PCI performed in comparable patients from the original SYNTAX-I trial. Longer term follow-up is awaited and a randomized clinical trial with contemporary CABG is warranted. ClinicalTrials.gov Identifier NCT02015832

Refolded dengue virus type 2 NS1 protein expressed in Escherichia coli preserves structural and immunological properties of the native protein

The dengue virus NS1 protein has been shown to be a protective antigen under different experimental conditions but the recombinant protein produced in bacterial expression systems is usually not soluble and loses structural and immunological features of the native viral protein. In the present study, experimental conditions leading to purification and refolding of the recombinant dengue virus type 2 (DENV-2) NS1 protein expressed in Escherichia coli are described. The refolded recombinant protein was recovered as heat-stable soluble dimers with preserved structural features, as demonstrated by spectroscopic methods. In addition, antibodies against epitopes of the NS1 protein expressed in eukaryotic cells recognized the refolded protein expressed in E. coli but not the denatured form or the same protein submitted to a different refolding condition. Collectively, the results demonstrate that the recombinant NS1 protein preserved important conformation and antigenic determinants of the native virus protein and represents a valuable reagent either for the development of vaccines or for diagnostic methods.

Boosting systemic and secreted antibody responses in mice orally immunized with recombinant Bacillus subtilis strains following parenteral priming with a DNA vaccine encoding the enterotoxigenic Escherichia coli (ETEC) CFA/I fimbriae B subunit

Recombinant Bacillus subtilis strains, either spores or vegetative cells, may be employed as safe and low cost orally delivered live vaccine vehicles. In this study, we report the use of an orally delivered B. subtilis vaccine strain to boost systemic and secreted antibody responses in mice i.m. primed with a DNA vaccine encoding the structural subunit (CfaB) of the CFA/I fimbriae encoded by enterotoxigenic Escherichia coli (ETEC), an important etiological agent of diarrhea among travelers and children living in endemic regions. DBA/2 female mice submitted to the prime-boost immunization regimen developed synergic serum (IgG) and mucosal (IgA) antibody responses to the target CfaB antigen. Moreover, in contrast to mice immunized only with one vaccine formulation, sera harvested from prime-boosted vaccinated individuals inhibited adhesion of ETEC cells to human red blood cells. Additionally, vaccinated dams conferred full passive protection to suckling newborn mice challenged with a virulent ETEC strain. Taken together the present results further demonstrate the potential use of recombinant B. subtilis strains as an alternative live vaccine vehicle.

Bacillus subtilis spores as vaccine adjuvants: further insights into the mechanisms of action.

Bacillus subtilis spores have received growing attention regarding potential biotechnological applications, including the use as probiotics and in vaccine formulations. B. subtilis spores have also been shown to behave as particulate vaccine adjuvants, promoting the increase of antibody responses after co-administration with antigens either admixed or adsorbed on the spore surface. In this study, we further evaluated the immune modulatory properties of B. subtilis spores using a recombinant HIV gag p24 protein as a model antigen. The adjuvant effects of B. subtilis spores were not affected by the genetic background of the mouse lineage and did not induce significant inflammatory or deleterious effects after parenteral administration. Our results demonstrated that co-administration, but not adsorption to the spore surface, enhanced the immunogenicity of that target antigen after subcutaneous administration to BALB/c and C57BL/6 mice. Spores promoted activation of antigen presenting cells as demonstrated by the upregulation of MHC and CD40 molecules and enhanced secretion of pro-inflammatory cytokines by murine dendritic cells. In addition, in vivo studies indicated a direct role of the innate immunity on the immunomodulatory properties of B. subtilis spores, as demonstrated by the lack of adjuvant effects on MyD88 and TLR2 knockout mouse strains.

Gut Adhesive Bacillus subtilis Spores as a Platform for Mucosal Delivery of Antigens

ABSTRACT Bacillus subtilis spores have been used as safe and heat-resistant antigen delivery vectors. Nonetheless, the oral administration of spores typically induces weak immune responses to the passenger antigens, which may be attributed to the fast transit through the gastrointestinal tract. To overcome this limitation, we have developed B. subtilis spores capable of binding to the gut epithelium by means of expressing bacterial adhesins on the spore surface. The resulting spores bound to in vitro intestinal cells, showed a longer transit through the mouse intestinal tract, and interacted with Peyers patch cells. The adhesive spores increased the systemic and secreted antibody responses to the Streptococcus mutans P1 protein, used as a model antigen, following oral, intranasal, and sublingual administration. Additionally, P1-specific antibodies efficiently inhibited the adhesion of the oral pathogen Streptococcus mutans to abiotic surfaces. These results support the use of gut-colonizing B. subtilis spores as a new platform for the mucosal delivery of vaccine antigens.

Late thrombotic events after bioresorbable scaffold implantation: a systematic review and meta-analysis of randomized clinical trials

Aims To compare the long-term safety and efficacy of bioresorbable vascular scaffold (BVS) with everolimus-eluting stent (EES) after percutaneous coronary interventions. Methods and results A systematic review and meta-analysis of randomized clinical trials comparing clinical outcomes of patients treated with BVS and EES with at least 24 months follow-up was performed. Adjusted random-effect model by the Knapp-Hartung method was used to compute odds ratios (OR) and 95% confidence intervals (CI). The primary safety outcome of interest was the risk of definite/probable device thrombosis (DT). The primary efficacy outcome of interest was the risk of target lesion failure (TLF). Five randomized clinical trials (n = 1730) were included. Patients treated with Absorb BVS had a higher risk of definite/probable DT compared with patients treated with EES (OR 2.93, 95%CI 1.37-6.26, P = 0.01). Very late DT (VLDT) occurred in 13 patients [12/996 (1.4%, 95%CI: 0.08-2.5) Absorb BVS vs. 1/701 (0.5%, 95%CI: 0.2-1.6) EES; OR 3.04; 95%CI 1.2-7.68, P = 0.03], 92% of the VLDT in the BVS group occurred in the absence of dual antiplatelet therapy (DAPT). Patients treated with Absorb BVS had a trend towards higher risk of TLF (OR 1.48, 95%CI 0.90-2.42, P = 0.09), driven by a higher risk of target vessel myocardial infarction and ischaemia-driven target lesion revascularization. No difference was found in the risk of cardiac death. Conclusion Compared with EES, the use of Absorb BVS was associated with a higher rate of DT and a trend towards higher risk of TLF. VLDT occurred in 1.4% of the patients, the majority of these events occurred in the absence of DAPT.

Single or dual antiplatelet therapy after PCI

The optimal duration and type of antiplatelet therapy after implantation of a drug-eluting stent (DES) remains uncertain. At the time of the first-in-man implantation of the sirolimus DES in 1999, the protocol-defined dual antiplatelet therapy (DAPT) duration was only 2 months. Subsequently, DAPT duration was extended to 1 year on the basis of anecdotal historical data, and this practice was then incorporated into clinical guidelines. For >1 decade, trialists have sought to compare the safety and efficacy of abbreviated (<6 months) and prolonged (>12 months) DAPT regimens. However, the body of evidence is limited by the heterogeneity of end points, time of randomization, and bleeding criteria used in each trial. Pharmaceutical advances led to the introduction of new ADP-receptor antagonists, which are thought to be more effective than clopidogrel. The ADP-receptor antagonists moved the focus from the optimal duration of DAPT to the potential efficacy of single antiplatelet therapy after DES implantation. In this Review, we summarize the current evidence on the duration of DAPT and the risk of bleeding and adverse cardiac events after DES implantation, and describe the pitfalls of trial interpretation. The ongoing, prospective trials to test single antiplatelet therapy after DES implantation are also discussed.

Impact of the SYNTAX scores I and II in patients with diabetes and multivessel coronary disease: a pooled analysis of patient level data from the SYNTAX, PRECOMBAT, and BEST trials

Aims To assess the impact of the SYNTAX scores I and II in outcomes after percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) for patients with diabetes and multivessel disease (MVD). Methods and results We performed a patient-level pooled analysis of three large randomized trials of patients with MVD. The impact of coronary anatomic complexity as measured by the SYNTAX score in the differences in outcomes following PCI and CABG was assessed at a median follow-up of 5 years. We also assessed the performance of the SYNTAX II score model in patients with and without diabetes. From the 3280 patients enrolled in the three trials, a total of 1068 (32.6%) had diabetes. The rate of the composite of death, myocardial infarction (MI), or stroke was similar in the PCI and CABG arms in patients with low-intermediate (≤32) SYNTAX scores (15.1% vs. 14.9%, respectively; P = 0.93) while it was significantly higher in the PCI arm in patients with high (≥33) SYNTAX scores (24.5% vs. 13.2%, respectively; P = 0.018). The SYNTAX score II showed good calibration and moderate discrimination ability in patients with diabetes (c-index = 0.68) as well as in those without (c-index = 0.67). Conclusions Differences in 5 years outcomes following PCI and CABG for patients with MVD and diabetes were influenced by anatomic complexity as measured by the SYNTAX score. The SYNTAX score II mortality prediction model showed similar performance regardless of the diabetes status.

Induction of neutralizing antibodies in mice immunized with an amino-terminal polypeptide of Streptococcus mutans P1 protein produced by a recombinant Bacillus subtilis strain

The oral pathogen Streptococcus mutans expresses a surface protein, P1, which interacts with the salivary pellicle on the tooth surface or with fluid-phase saliva, resulting in bacterial adhesion or aggregation, respectively. P1 is a target of protective immunity. Its N-terminal region has been associated with adhesion and aggregation functions and contains epitopes recognized by efficacious antibodies. In this study, we used Bacillus subtilis, a gram-positive expression host, to produce a recombinant N-terminal polypeptide of P1 (P1(39-512)) derived from the S. mutans strain UA159. Purified P1(39-512) reacted with an anti-full-length P1 antiserum as well as one raised against intact S. mutans cells, indicating preserved antigenicity. Immunization of mice with soluble and heat-denatured P1(39-512) induced antibodies that reacted specifically with native P1 on the surface of S. mutans cells. The anti-P1(39-512) antiserum was as effective at blocking saliva-mediated aggregation of S. mutans cells and better at blocking bacterial adhesion to saliva-coated plastic surfaces compared with the anti-full-length P1 antiserum. In addition, adsorption of the anti-P1 antiserum with P1(39-512) eliminated its ability to block the adhesion of S. mutans cells to abiotic surfaces. The present results indicate that P1(39-512), expressed and purified from a recombinant B. subtilis strain, maintains important immunological features of the native protein and represents an additional tool for the development of anticaries vaccines.

Is quantitative coronary angiography reliable in assessing the lumen gain after treatment with the everolimus-eluting bioresorbable polylactide scaffold?

AIMS The current study aimed to assess the difference in lumen dimension measurements between optical coherence tomography (OCT) and quantitative coronary angiography (QCA) in the polymeric bioresorbable scaffold and metallic stent. METHODS AND RESULTS In the randomised ABSORB Japan trial, 87 lesions in the Absorb arm and 44 lesions in the XIENCE arm were analysed. Post-procedural OCT-QCA lumen dimensions were assessed in matched proximal/distal non-stented/non-scaffolded reference (n=199), scaffolded (n=145) and stented (n=75) cross-sections at the two device edges using the Bland-Altman method. In the non-stented/non-scaffolded reference segments, QCA systematically underestimated lumen diameter (LD) compared with OCT (accuracy, -0.26 mm; precision, 0.47 mm; 95% limits of agreement as a mean bias±1.96 standard deviation, -1.18-0.66 mm). When compared to OCT, QCA of the Absorb led to a more severe underestimation of the LD (-0.30 mm; 0.39 mm; -1.06-0.46 mm) than with the XIENCE (-0.14 mm; 0.31 mm; -0.75-0.46 mm). QCA underestimated LD by 9.1%, 4.9%, and 9.8% in the reference, stented, and scaffolded segments, respectively. The protrusion distance of struts was larger in the Absorb arm than in the XIENCE arm (135±27 µm vs. 18±26 µm, p<0.001), and may have contributed to the observed differences. CONCLUSIONS In-device QCA measurement was differently affected by the presence of a metallic or polymeric scaffold, a fact that had a significant impact on the QCA assessment of acute gain and post-procedural minimum LD.