Development of a hyperimmune equine serum therapy for COVID-19 in Argentina

The disease named COVID-19, caused by the SARS-CoV-2 coronavirus, is currently generating a global pandemic. Vaccine development is no doubt the best long-term immunological approach, but in the current epidemiologic and health emergency there is a need for rapid and effective solutions. Convalescent plasma is the only antibody-based therapy available for COVID-19 patients to date. Equine polyclonal antibodies (EpAbs) put forward a sound alternative. The new generation of processed and purified EpAbs containing highly purified F(ab’)2 fragments demonstrated to be safe and well tolerated. EpAbs are easy to manufacture allowing a fast development and scaling up for a treatment. Based on these ideas, we present a new therapeutic product obtained after immunization of horses with the receptor-binding domain of the viral Spike glycoprotein. Our product shows around 50 times more potency in in vitro seroneutralization assays than the average of convalescent plasma. This result may allow us to test the safety and efficacy of this product in a phase 2/3 clinical trial to be conducted in July 2020 in the metropolitan area of Buenos Aires, Argentina.

La enfermedad denominada COVID-19 es causada por el coronavirus SARS-CoV-2 y es actualmente considerada una pandemia a nivel global. El desarrollo de vacunas es sin duda la mejor estrategia a largo plazo, pero debido a la emergencia sanitaria, existe una necesidad urgente de encontrar soluciones rápidas y efectivas para el tratamiento de la enfermedad. Hasta la fecha, el uso de plasma de convalecientes es la única inmunoterapia disponible para pacientes hospitalizados con COVID-19. El uso de anticuerpos policlonales equinos (EpAbs) es otra alternativa terapéutica interesante. La nueva generación de EpAbs incluyen el procesamiento y purificación de los mismos y la obtención de fragmentos F(ab’)2 con alta pureza y un excelente perfil de seguridad en humanos. Los EpAbs son fáciles de producir, lo cual permite el desarrollo rápido y la elaboración a gran escala de un producto terapéutico. En este trabajo mostramos el desarrollo de un suero terapéutico obtenido luego de la inmunización de caballos utilizando el receptor-binding domain de la glicoproteína Spike del virus. Nuestro producto mostró ser alrededor de 50 veces más potente en ensayos de seroneutralización in vitro que el promedio de los plasmas de convalecientes. Estos resultados nos permitirían testear la seguridad y eficacia de nuestro producto en ensayos clínicos de fase 2/3 a realizarse a partir de julio de 2020 en la zona metropolitana de Buenos Aires, Argentina.

Desarrollo de un producto anti-toxina shiga para la prevención del síndrome urémico hemolítico / Development of a product anti-Shiga toxin for prevention of the hemolytic uremic syndrome

El síndrome urémico hemolítico (SUH) típico es una enfermedad huérfana causada por cepas de Escherichia coli productoras de toxina Shiga (Stx) y caracterizada por daño renal agudo, anemia hemolítica microangiopática y plaquetopenia. Es endémico en Argentina, el país con mayor incidencia de SUH en el mundo. Debido al rol fundamental de la Stx en su patogenia, se puede considerar que, como otras toxemias conocidas, el SUH podría ser tratado con anticuerpos. Este trabajo describe el desarrollo de un nuevo tratamiento capaz de neutralizar el efecto tóxico de distintas variantes de la Stx. El tratamiento consiste en fragmentos F(ab')2 provenientes de un antisuero equino cuya eficacia y potencia contra Stx1 y Stx2 se comprobó en diferentes modelos preclínicos. El producto mostró ser seguro en animales, presentó la farmacocinética descripta para compuestos similares y se pudo establecer una posible ventana terapéutica para su adecuada administración. En conjunto, los resultados preclínicos obtenidos validan la realización de un estudio clínico de primer uso en humanos. En dicho estudio, que se realizará en el Hospital Italiano de Buenos Aires, se analizará la seguridad y la farmacocinética del producto en voluntarios adultos sanos. Estos resultados sentarán las bases para la realización del estudio clínico fase II en pacientes pediátricos con infección por cepas de E. coli productoras de Stx.

The typical hemolytic uremic syndrome (HUS) is an orphan disease caused by Shiga toxin(Stx) -producing Escherichia coli strains and characterized by acute kidney damage, microangiopathic hemolytic anemia and low platelet count. It is endemic in Argentina, the country with the highest incidence of HUS in the world. Stx is essential for its development and therefore, HUS is considered a toxemic non-bacteremic disorder, which could be treated with antibodies. Herein we describe the development of a new treatment capable of neutralizing the toxic effect of Stx and its variants. The treatment consists of F(ab')2 fragments from an equine antiserum whose efficacy and potency against Stx1 and Stx2 were proved in different preclinical models. The product was shown to be safe in animals. Furthermore, the anti-Stx F(ab')2 pharmacokinetic was shown to be similar to that of analogous compounds and a therapeutic window for its administration was determined. Altogether, these preclinical results warrant testing in humans. The phase I clinical trial will be performed at the Hospital Italiano in Buenos Aires to evaluate the safety and pharmacokinetics of the product in healthy adult volunteers. Based on the results of this study, a phase II clinical trial will be planned in pediatric patients diagnosed with infection by Stx-producing E. coli strains.

Quality of horse F(ab)2 antitoxins and antirabies immunoglobulins: protein content and anticomplementary activity

Background Among other applications, immunotherapy is used for the post-exposure treatment and/or prophylaxis of important infectious diseases, such as botulism, diphtheria, tetanus and rabies. The effectiveness of serum therapy is widely proven, but improvements on the immunoglobulin purification process and on the quality control are necessary to reduce the amount of protein aggregates. These may trigger adverse reactions in patients by activating the complement system and inducing the generation of anaphylatoxins. Herein, we used immunochemical methods to predict the quality of horse F(ab)2 anti-botulinum AB, anti-diphtheric, antitetanic and anti-rabies immunoglobulins, in terms of amount of proteins and protein aggregates. Methods Samples were submitted to protein quantification, SDS-PAGE, Western blot analysis and molecular exclusion chromatography. The anticomplementary activity was determined in vitro by detecting the production of C5a/C5a desArg, the most potent anaphylatoxin. Data were analyzed by one-way ANOVA followed by Tukey's post-test, and differences were considered statistically significant when p 0.05. Results Horse F(ab)2 antitoxins and anti-rabies immunoglobulin preparations presented different amounts of protein. SDS-PAGE and Western blot analyses revealed the presence of protein aggregates, non-immunoglobulin contaminants and, unexpectedly, IgG whole molecules in the samples, indicating the non-complete digestion of immunoglobulins. The chromatographic profiles of antitoxins and anti-rabies immunoglobulins allowed to estimate the percentage of contaminants and aggregates in the samples. Although protein aggregates were present, the samples were not able to induce the generation of C5a/C5a desArg in vitro, indicating that they probably contain acceptable levels of aggregates...

Quality of horse F(ab')2 antitoxins and antirabies immunoglobulins: protein content and anticomplementary activity

Among other applications, immunotherapy is used for the post-exposure treatment and/or prophylaxis of important infectious diseases, such as botulism, diphtheria, tetanus and rabies. The effectiveness of serum therapy is widely proven, but improvements on the immunoglobulin purification process and on the quality control are necessary to reduce the amount of protein aggregates. These may trigger adverse reactions in patients by activating the complement system and inducing the generation of anaphylatoxins. Herein, we used immunochemical methods to predict the quality of horse F(ab′)2 anti-botulinum AB, anti-diphtheric, antitetanic and anti-rabies immunoglobulins, in terms of amount of proteins and protein aggregates. Methods Samples were submitted to protein quantification, SDS-PAGE, Western blot analysis and molecular exclusion chromatography. The anticomplementary activity was determined in vitro by detecting the production of C5a/C5a desArg, the most potent anaphylatoxin. Data were analyzed by one-way ANOVA followed by Tukey's post-test, and differences were considered statistically significant when p < 0.05. Results Horse F(ab′)2 antitoxins and anti-rabies immunoglobulin preparations presented different amounts of protein. SDS-PAGE and Western blot analyses revealed the presence of protein aggregates, non-immunoglobulin contaminants and, unexpectedly, IgG whole molecules in the samples, indicating the non-complete digestion of immunoglobulins. The chromatographic profiles of antitoxins and anti-rabies immunoglobulins allowed to estimate the percentage of contaminants and aggregates in the samples. Although protein aggregates were present, the samples were not able to induce the generation of C5a/C5a desArg in vitro, indicating that they probably contain acceptable levels of aggregates. Conclusions Anti-botulinum AB (bivalent), anti-diphtheric, antitetanic and anti-rabies horse F(ab′)2 immunoglobulins probably contain acceptable levels of aggregates, although other improvements on the preparations must be carried out. Protein profile analysis and in vitro anticomplementary activity of F(ab′)2 immunoglobulin preparations should be included as quality control steps, to ensure acceptable levels of aggregates, contaminants and whole IgG molecules on final products, reducing the chances of adverse reactions in patients.(AU)

The binding of a monoclonal antibody to the apical region of SCARB2 blocks EV71 infection

Entero virus 71 (EV71) causes hand, foot, and mouth disease (HFMD) and occasionally leads to severe neurological complications and even death. Scavenger receptor class B member 2 (SCARB2) is a functional receptor for EV71, that mediates viral attachment, internalization, and uncoating. However, the exact binding site of EV71 on SCARB2 is unknown. In this study, we generated a monoclonal antibody (mAb) that binds to human but not mouse SCARB2. It is named JL2, and it can effectively inhibit EV71 infection of target cells. Using a set of chimeras of human and mouse SCARB2, we identified that the region containing residues 77-113 of human SCARB2 contributes significantly to JL2 binding. The structure of the SCARB2-JL2 complex revealed that JL2 binds to the apical region of SCARB2 involving α-helices 2, 5, and 14. Our results provide new insights into the potential binding sites for EV71 on SCARB2 and the molecular mechanism of EV71 entry.

Gene mutations of platelet glycoproteins and response to tirofiban in acute coronary syndrome / Mutações gênicas das glicoproteínas plaquetárias e resposta ao tirofiban na síndrome coronariana aguda

CONTEXT AND OBJECTIVES: Glycoprotein inhibitors (abciximab, eptifibatide and tirofiban) are used in patients with unstable angina and non-ST-segment elevation myocardial infarction before percutaneous coronary intervention. Of these, tirofiban is the least effective. We hypothesized that the response to tirofiban might be associated with glycoprotein gene mutations. DESIGN AND SETTING: Prospective study at Emergency Unit, Heart Institute (InCor), University of São Paulo. METHOD: Intrahospital evolution and platelet aggregation in response to tirofiban were analyzed in relation to four glycoprotein mutations in 50 patients indicated for percutaneous coronary intervention: 17 (34%) with unstable angina and 33 (66%) with non-ST-segment elevation myocardial infarction. Platelet aggregation was analyzed using the Born method. Blood samples were obtained before and one hour after tirofiban infusion. Glycoproteins Ia (807C/T ), Ib (Thr/Met) , IIb (Ile/Ser ) and IIIa (PIA ) were the mutations selected. RESULTS: Hypertension, dyslipidemia, diabetes, smoking, previous coronary artery disease and stroke were similar between the groups. Mutant glycoprotein IIIa genotypes had lower platelet aggregation before tirofiban administration than that of the wild genotype (41.0% ± 22.1% versus 55.9% ± 20.8%; P = 0.035). Mutant glycoprotein IIIa genotypes correlated moderately with lower platelet inhibition (r = -0.31; P = 0.030). After tirofiban administration, platelet glycoprotein Ia, Ib, IIb and IIIa mutations did not influence the degree of inhibition of platelet aggregation or intrahospital mortality. CONCLUSIONS: Mutations of glycoproteins Ia, Ib, IIb and IIIa did not influence platelet aggregation in response to tirofiban in patients with unstable angina and non-ST-segment elevation myocardial infarction.

RESUMO CONTEXTO E OBJETIVOS: Inibidores da glicoproteína (abciximab, eptifibatide, tirofiban) são utilizados em pacientes com angina instável e infarto do miocárdio sem elevação do segmento ST (IAMSSST) antes da intervenção coronária percutânea. Dentre eles, o tirofiban é o menos eficaz. Nossa hipótese é que a resposta ao tirofiban possa estar associada a mutações no gene da glicoproteína. DESENHO E LOCAL: Estudo prospectivo na Unidade de Emergência do Instituto do Coração (InCor), Universidade de São Paulo (USP). MÉTODOS: Foram analisadas a evolução intra-hospitalar e agregabilidade plaquetária em resposta ao tirofiban de 4 mutações da glicoproteína em 50 pacientes com indicação para intervenção coronária percutânea, 17 (34%) com angina instável e 33 (66%) com IAMSSST. A agregação plaquetária foi analisada pelo método de Born. Amostras de sangue foram obtidas antes e uma hora após infusão do tirofiban. As glicoproteínas Ia (807C/T ), Ib (Thr/Met ), IIb (Ile/Ser ) e IIIa (PIA ) foram as mutações selecionadas. RESULTADOS: Hipertensão, dislipidemia, diabetes, tabagismo, doença coronariana e acidente vascular cerebral prévios foram semelhantes entre os grupos. Observou-se menor agregabilidade plaquetária dos genótipos mutantes da glicoproteína IIIa antes da administração de tirofiban do genótipo selvagem (41% ± 22% versus 56% ± 21%; P = 0,035). Genótipos mutantes da glicoproteína IIIa correlacionaram-se moderadamente com menor inibição plaquetária (r = -0,31; P = 0,030). Após a administração tirofiban, as mutações das glicoproteínas Ia, Ib, IIb, e IIIa não influenciaram o grau de inibição da agregação plaquetária e mortalidade intra-hospitalar. CONCLUSÕES: Mutações das glicoproteínas Ia, Ib, IIb e IIIa não influenciaram a agregação plaquetária em resposta ao tirofiban nos pacientes com angina instável e IAMSSST.

FabAV antivenin use after copperhead snakebite: clinically indicated or knee-jerk reaction?

Abstract Background Crotalidae Polyvalent Immune Fab (Ovine) (FabAV) antivenin is commonly recommended after pit viper snakebites. Because copperhead envenomations are usually self-limited, some physicians are reluctant to use this costly treatment routinely, while others follow a more liberal approach. We hypothesized that, in practice, only patients with evidence of significant (moderate or severe) copperhead envenomation [those with snakebite severity score (SSS) > 3] receive FabAV and examined a large cohort to determine the relationship between clinical findings and FabAV administration. Methods All data from patients evaluated for copperhead snakebite at a rural tertiary referral center from 5/2002 to 10/2013 were compiled. Demographics, transfer status, antivenin use, and clinical findings were collected; SSS was calculated. The relationships among FabAV use, clinical findings, and SSS were analyzed using t-test, chi-square, and Pearson’s coefficient (p < 0.05 was significant). Results During the study period, 318 patients were treated for copperhead snakebite; 44 (13.8 %) received antivenin. Median dose was four vials (range: 1–10; IQR: 4,6). There were no deaths. Most patients receiving FabAV (63.6 %) were admitted. With regard to demographics and symptoms, only the degree of swelling (moderate vs. none/mild; p < 0.01) and bite location (hand/arm vs. leg: p < 0.0001) were associated with FabAV use. A SSS > 3, indicating moderate or severe envenomation, was only very weakly correlated with antivenin use (r = 0.217;p < 0.0001). The majority of patients with SSS > 3 (65.8 %) did not receive antivenin while most patients who did receive antivenin (70.5 %) had SSS ≤ 3 (indicating mild envenomation). Conclusions Considerable variation occurs in antivenin administration after copperhead snakebite. Use of FabAV appears poorly correlated with patients’ symptoms. This practice may expose patients to the risks of antivenin and increasing costs of medical care without improving outcomes. Guidelines used for treating other pit viper strikes, such as rattlesnake or cottonmouth snakebite may be too liberal for copperhead envenomations. Our data suggests that most patients with mild or moderate envenomation appear to do well independent of FabAV use. We suggest, for patients with copperhead snakebite, that consideration be given to withholding FabAV for those without clinical evidence of severe envenomation until prospective randomized data are available.

Development of human antibodies against the Gn protein of severe fever with thrombocytopenia syndrome virus / 病毒学报

To obtain human antibodies against the Gn protein of Severe fever with thrombocytopenia syndrome virus (SFTSV) with phage display technology, this study aimed to screen anti-Gn protein antibodies from an anti-SFTSV Fab human phage display library. Antibody genes were identified by sequence analysis and the specificity of antibodies was confirmed by ELISA. The Fab antibody genes were cloned into the HL51-14 vector and expressed in a mammalian cell expression system. IgG antibodies were then purified by protein A affinity chromatography,and the results were further confirmed by ELISA,IFA,western blotting assays and micro-neutralization tests. The results showed that, after three rounds of panning, there were 390 human Fab antibodies against SFTSV particles, of which 364 were specific for nucleoprotein. Coated with the Gn protein, eight different Fab antibodies specific for Gn protein were obtained after the determination of the subtype and subclass of antibodies by gene sequencing; five of these antibodies were from the Lambda library and three were from the Kappa library. The eight IgG antibodies could specifically bind to Gn protein according to the ELISA, IFA and Western blotting assays. The micro-neutralization test showed that these eight antibodies had no neutralizing activity,but they could still provide a reference for research in human monoclonal antibodies against SFTSV.

Efficacy of Combination Treatment with Intracoronary Abciximab and Aspiration Thrombectomy on Myocardial Perfusion in Patients with ST-Segment Elevation Myocardial Infarction Undergoing Primary Coronary Stenting

PURPOSE: We aimed to investigate whether combination therapy using intracoronary (IC) abciximab and aspiration thrombectomy (AT) enhances myocardial perfusion compared to each treatment alone in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). MATERIALS AND METHODS: We enrolled 40 patients with STEMI, who presented within 6 h of symptom onset and had Thrombolysis in MI flow 0/1 or a large angiographic thrombus burden (grade 3/4). Patients were randomly divided into 3 groups: 10 patients who received a bolus of IC abciximab (0.25 mg/kg); 10 patients who received only AT; and 20 patients who received both treatments. The index of microcirculatory resistance (IMR) was measured with a pressure sensor/thermistor-tipped guidewire following successful PCI. Microvascular obstruction (MVO) was assessed using cardiac magnetic resonance imaging on day 5. RESULTS: IMR was lower in the combination group than in the IC abciximab group (23.5+/-7.4 U vs. 66.9+/-48.7 U, p=0.001) and tended to be lower than in the AT group, with barely missed significance (23.5+/-7.4 U vs. 37.2+/-26.1 U, p=0.07). MVO was observed less frequently in the combination group than in the IC abciximab group (18.8% vs. 88.9%, p=0.002) and tended to occur less frequently than in the AT group (18.8% vs. 66.7%, p=0.054). No difference of IMR and MVO was found between the IC abciximab and the AT group (66.9+/-48.7 U vs. 37.2+/-26.1 U, p=0.451 for IMR; 88.9% vs. 66.7%, p=0.525 for MVO, respectively). CONCLUSION: Combination treatment using IC abciximab and AT may synergistically improve myocardial perfusion in patients with STEMI undergoing primary PCI (Trial Registration: clinicaltrials. gov Identifier: NCT01404507).

Comparison between intracoronary abciximab and intravenous eptifibatide administration during primary percutaneous coronary intervention of acute ST-segment elevation myocardial infarction

Administration of glycoprotein 2b/3a inhibitors is an effective adjunctive treatment strategy during primary percutaneous coronary intervention [PPCI] for ST-segment elevation myocardial infarction [STEMI]. Recent data suggest that an intracoronary administration of these drugs can increase the efficacy of PPCI. This study was done to find any potential difference in terms of efficacy of administering intracoronary Abciximab vs. intravenous Eptifibatide in primary PPCI. A total of 40 STEMI patients who underwent PPCI within 12 hours of symptom onset were randomized to either an intracoronary Abciximab [0.25 microg/kg] bolus or two boluses of intravenous Eptifibatide [0.180 microg/kg] each 10 minutes. The primary end points were enzymatic infarct size, myocardial reperfusion measured as ST-segment resolution [STR], and post-procedural thrombolysis in myocardial infarction [TIMI] grade flow of the infarct-related artery. The secondary end points were intra-procedural adverse effect [arrhythmia] and no-reflow phenomenon, in-hospital mortality, reinfarction, hemorrhage, and post-procedural global systolic function. Post-procedural TIMI grade 3 flow was achieved in 95% and 90% of the intracoronary Abciximab and intravenous Eptifibatide groups, respectively [p value = 0.61]. The infarct size, as assessed by the area under the curve of creatine phosphokinase-MB in the first 48 hours after PPCI [micromol/L/hr], was similar between the intracoronary Abciximab and intravenous Eptifibatide groups: 6591 [interquartile range [IQR], 3006.0 to 11112.0] versus 7,294 [IQR, 3795.5 to 11803.5]; p value = 0.59. Complete STR was achieved in 55% and 45% of the intracoronary Abciximab and intravenous Eptifibatide groups, respectively [p value = 0.87]. No deaths, urgent revascularizations, reinfarctions, or TIMI major bleeding events were observed in either group. The intracoronary administration of Abciximab was not superior to the intravenous administration of Eptifibatide in the STEMI patients who underwent primary PCI

Identification of human monoclonal HIV-1-neutralizing antibodies from phage antibody library by cell-based screening / 病毒学报

To identify human monoclonal HIV-l-neutralizing antibodies from an HIV-1 CRF07BC specific phage display antibody library by cell-based screening. 293T cells were transfected by pCH064. 2-Env plas mid and then used to biopan the phage antibody library. The positive phage clones were screened by cell based ELISA and sequenced for the variable region of heavy (VH) and light (VL) chains. The expressed Fabs were purified by Ni(+2) -NTA column and analyzed by SDS-PAGE. The cell- and gp120 protein-based ELISA as well as flow cytometry were used to measure Fab's binding activity. The neutralizing activity of Fabs was assessed by HIV-1 pseudoviruses. After 4-round biopanning, the binding phages to transfected cells were enriched about 650-folds. A total of 28 positive clones were screened out by cell ELISA and sequence analysis identified 5 different Fabs possessing unique VH and VL (2801, 2837, 2863, 2870 and 2920). Interestingly, these Fabs reacted with the Env-transfected 293T cells but not soluble gp120 proteins, suggesting that they might target conformation-dependent epitopes presenting on viral Env complex. We found that three Fabs (2801, 2863, 2870) exhibited potent neutralizing activity against CRF07_BC isolate CH120. 6 with IC50 of 2.24, 0.89 and 3.09 microg/mL respectively, and that 2801 and 2863 cross-neutral ized the subtype B isolate SF162 at IC50 of 0.69 and 3.52 microg/mL respectively. In conclusion, the HIV-1 Env-transfected 293T cells can be used to efficiently enrich and screen the phage antibody library and isolate human monoclonal HIV-1-neutralizing Fabs that target the Env complex-dependent conformational epitopes. Therefore, our studies provide a powerful platform for exploring the mechanism of HIV-1 neu tralizing response and for designing AIDS vaccines.

Patients with Arthritis Undergoing Surgery: How Should We Manage Tumour Necrosis Factor Blocking Agents Perioperatively?: A Systematic Literature Review

We systematically reviewed the literature on the infectious risk in patients treated with tumour necrosis factor blocking agents (TNF-BA) undergoing surgery: we searched the Medline (PubMed) and the online archive from the Annual European Congress of Rheumatology and the Annual Scientific Meeting of the American College of Rheumatology. Of total 1259 reports, 14 were finally analysed. With one exception all were retrospective. Four of 6 studies compared patients on TNF-BA with those not receiving TNF-BA, and found an increased risk of infection with the use of TNF-BA. None of the other studies which compared continued with discontinued treatment at surgery found an increased risk of infection, when the medication was continued perioperatively. In conclusion, while in theory there is an increased risk of infections when TNF-BA are administered perioperatively, the available literature does not necessarily support this. It rather appears that patients receiving TNF-BA are a priori at a higher risk of postoperative infections. Scheduling surgery at the end of the drug interval and adding one "safety" week prior to surgery should be an acceptable plan in daily clinical practice.

Acute Profound Thrombocytopenia after Using Abciximab for No-Reflow during Primary Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction

Glycoprotein IIb/IIIa antagonists are well established for their effectiveness in improving clinical outcomes in acute coronary syndrome patients undergoing percutaneous coronary intervention. Acute profound thrombocytopenia is a rare complication of abciximab. We present a case which was managed successfully for the rare complication of acute profound thrombocytopenia after using abciximab and an intra-aortic balloon pump for the treatment of a no-reflow phenomenon and consecutive cardiogenic shock during primary percutaneous coronary intervention.

Effect of Abciximab on the Levels of Circulating Microparticles in Patients with Acute Myocardial Infarction Treated by Primary Angioplasty

BACKGROUND AND OBJECTIVES: We investigated the effect of the additional use of abciximab during percutaneous coronary intervention (PCI) on the level of procoagulant microparticles (MPs) in patients with ST-segment elevation myocardial infarction (STEMI) who had undergone primary PCI. SUBJECTS AND METHODS: In this study, we studied 86 patients with STEMI (72 men, age 58+/-13) who had undergone primary PCI. The decision to administer abciximab immediately prior to PCI was left to the discretion of the operator. Blood samples for analysis of MPs were obtained from the femoral artery before and after PCI. MPs with procoagulant potential were measured using a commercial kit. The cellular origins of MPs were determined by antigenic capture with specific antibodies. RESULTS: Procoagulant MPs captured onto annexin V were not changed significantly after PCI {13.4+/-13.2 nM vs. 13.2+/-16.1 nM phosphatidylserine equivalent (PS eq), p=0.479}. Abciximab was used in 30 of 86 patients (35%) immediately prior to PCI. In patients who had undergone PCI without abciximab, no significant change in the level of MPs was observed after PCI. However, in the abciximab group, the level of circulating MPs was significantly decreased after PCI (12.0+/-10.7 nM vs. 7.8+/-11.7 nM PS eq, p=0.018). Levels of endothelial- and platelet-derived MPs also showed a significant reduction after PCI in the abciximab group. CONCLUSION: Primary PCI with additional abciximab significantly reduced the level of procoagulant MPs regardless of their cellular origins in patients with STEMI.

A Case of Diffuse Alveolar Hemorrhage Following Abciximab Therapy / 대한내과학회지

Platelets play an important role in the development of acute coronary syndrome. Platelet-inhibiting drugs, such as glycoprotein IIb/IIIa inhibitors, can be beneficial when they are administered at the time of primary percutaneous coronary intervention for acute coronary syndrome. Although an increased risk for bleeding complications is well recognized, the risk associated with diffuse alveolar hemorrhage is much less reported. We report a case of diffuse alveolar hemorrhage after using abciximab.

Anterior Mediastinal Hematoma after Cardiopulmonary Resuscitation

Anterior mediastinal hematoma is often reported as a complication of cardiopulmonary resuscitation (CPR). CPR can be performed as a result of myocardial infarction, and early percutaneous coronary intervention (PCI) and anticoagulant, antiplatelet agent can improve outcome. As use of antiplatelet agents, like glycoprotein IIb/IIIa inhibitors, becomes more widespread, occurrence of complications such as bleeding may be increased. The mediastinal hematoma usually resolves itself without complications; however, a large amount of hematoma can cause cardiac tamponade. Therefore, rapid diagnosis is very important. We describe a case of anterior mediastinal hematoma detected by echocardiography after CPR and PCI.

Trombocitopenia aguda profunda asociada al uso de abciximab: a propósito de un caso / Acute profound thrombocytopenia associated with the use of abciximab: case report

Se presenta un paciente con angina inestable e intervención coronaria percutánea con stents, que desarrolló púrpura mucocutánea y hematoma inguinal asociados a trombocitopenia aguda profunda inducida por abciximab con nadir de 1 x 10(9)/L (1000 plaquetas/mm³), su recuperación con el tratamiento instituido y la complicación de trombosis subaguda intrastent asociada a cuenta plaquetaria funcional que requirió reintervención con angioplastía primaria y administración de tirofiban, un agente bloqueador del receptor IIb/IIIa diferente. Se realizaron estudios diagnósticos para investigar otras causas de trombocitopenia en estos pacientes que reciben heparina, antiplaquetarios como ácido acetilsalicílico y clopidogrel, asociados a bloqueadores del receptor IIb/IIIa. Se realizó una revisión de publicaciones con reporte de esta complicación.

We present the case-report of a patient with instable angina who submitted to percutaneous coronary intervention and stent place for revascularization who developed purpura and groin hematoma associated to acute profound thrombocytopenia induced by abciximab infusion with nadir platelet counts 1 x 10(9)/L (1,000 platelets/mm³), his platelet recovery with the instituted treatment and the outcome with subacute intra-stent thrombosis that was associated with functionally platelet counts that required a primary angioplasty and administration of tirofiban, a platelet glycoprotein IIb/IIIa receptor antagonist. Laboratory confirmation to exclude other causes of thrombocytopenia and its association of glycoprotein IIb/IIIa receptor antagonist with heparin, acetylsalicylic acid and clopidogrel were obtained. We perform in literature trials with this complication.

Inhibitory effects of the immunoconjugate composed of anti-type IV collagenase antibody Fab' fragment and lidamycin on tumor invasion and metastasis / 药学学报

This study is to investigate the tumor invasion and metastasis inhibition effects of the immunoconjugate composed of lidamycin and anti-type IV collagenase monoclonal antibody Fab' fragment. Boyden chamber assay was used to evaluate the influence of Fab'-LDM on HT-1080 cells invasion ability, gelatinase spectrum was used to measure the change of invasion factor MMP-2 and MMP-9's secretion, and RT-PCR was adopted to determine TIMP-1 mRNA expression level. The immunoconjugate inhibition of tumor in situ metastasis was also tested in nude mice. The Fab'-LDM conjugates had dose-dependent inhibition effect on HT-1080 cells' invasion. At the concentrations of 5 and 10 nmol L(-1), the Fab'-LDM inhibited the invasion by (60 +/- 12) % and (79 +/- 11) % respectively. At the concentration of 5 and 10 nmol L(-1), the Fab'-LDM inhibited the secretion of MMP-2 by (42 +/- 8) % and (54 +/- 6) % and that of MMP-9 by (57 +/- 3) % and (87 +/- 1) %, respectively. RT-PCR indicated that conjugates increased the anti-invasion factor TIMP-1 level. The in vivo experiment showed that, compared with the control group, the tumor inhibition rate in Fab', Fab'-LDM, and LDM group equaled to (30 +/- 13) %, (86 +/- 26) %, (74 +/- 22) % respectively. In conclusion, Fab'-LDM could inhibit the invasion and metastasis of tumor and it might be a new tumor biotherapy agent.

Urgent Recanalization with Stenting for Severe Intracranial Atherosclerosis after Transient Ischemic Attack or Minor Stroke

OBJECTIVE: Stenting of symptomatic intracranial stenosis has recently become an alternative treatment modality. However, urgent intracranial stenting in patients with intracranial stenosis following a transient ischemic attack (TIA) or minor stroke is open to dispute. We sought to assess the feasibility, safety, and effectiveness of urgent intracranial stenting for severe stenosis (>70%) in TIA or minor stroke patients. METHODS: Between June 2009 and October 2010, stent-assisted angioplasty by using a balloon-expandable coronary stent for intracranial severe stenosis (>70%) was performed in 7 patients after TIA and 5 patients after minor stroke (14 stenotic lesions). Technical success rates, complications, angiographic findings, and clinical outcomes were retrospectively analyzed. RESULTS: Stenting was successful in all 12 patients. The mean time from symptom onset to stenting was 2.1 days (1-8 days). Post-procedural angiography showed restoration to a normal luminal diameter in all patients. In-stent thrombosis occurred in one patient (n=1, 8.3%), and was lysed with abciximab. No device-related complications, such as perforations or dissections at the target arteries or intracranial hemorrhaging, occurred in any patient. The mortality rate was 0%. No patient had an ischemic event over the mean follow-up period of 12.5 months (range, 7-21 months), and follow-up angiography (n=7) revealed no significant in-stent restenosis (>50%). CONCLUSION: Urgent recanalization with stenting is feasible, safe, and effective in patients with TIA or acute minor stroke with intracranial stenosis of > or =70%.