Three-year outcomes of selective incomplete versus complete revascularization in heart failure patients receiving multivessel percutaneous coronary intervention

Background

Heart failure (HF) patients with multi-vessel disease (MVD) are often associated with comorbidities to limit the possibility to achieve complete revascularization (CR) in percutaneous coronary intervention (PCI). The planned selective incomplete revascularization (SIR) may be an alternative opinion for these patients.

Purpose

To investigate 3-year clinical outcomes of SIR versus CR in HF patients with MVD in a real-word registry.

Methods

A total of 566 HF patients with MVD receiving either SIR or CR were enrolled. SIR was planned pre-PCI based on clinical exams to avoid non-viable tissue revascularization. Major adverse cardiac events (MACEs) was a composite of in-hospital death, recurrent myocardial infarction, any revascularization, and all-cause death at 3-year follow-up.

Results

There was no significant differences between SIR and CR groups in in-hospital death, any revascularization, all-cause death and MACEs (24.3% vs. 24.9%, p=0.922). However, SIR had a significant lower incidence of recurrent myocardial infarction than CR (3.2% vs. 7.2%, p=0.032).

Conclusion

The 3-year outcomes of PCI with planned SIR were completely comparable to with CR in HF patients with MVD. Planned SIR can be an opinion for HF patients with MVD who are not suitable to achieve CR.

Kaplan-Meier curve of 3-year MACEs

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Chang Gung Medical Research Program

Ticagrelor monotherapy vs clopidogrel monotherapy in patients with acute coronary syndrome undergoing percutaneous coronary intervention

Background

P2Y12 inhibitor monotherapy with either clopidogrel or ticagrelor becomes an alternative antiplatelet strategy in patients (pts) undergoing percutaneous coronary intervention (PCI). The purpose of this study was to compare the efficacy and safety of clopidogrel vs. ticagrelor monotherapy in pts with acute coronary syndrome (ACS) undergoing PCI who cannot tolerate aspirin.

Methods and results

From January 1, 2014 to December 31, 2018, a total of 610 ACS pts (mean age 70.4±13.1 years, 72.1% men, 28.5% STEMI) that aspirin was stopped prematurely for various reasons and received either clopidogrel (n=369) or ticagrelor (n=241) monotherapy were included from 8 major hospitals in Taiwan. The duration (median and the 25th and 75th percentile) of aspirin treatment was 9 (1.39–37.00) days in the clopidogrel group and 10 (1.00–55.00) days in the ticagrelor group (p=0.514). Gastrointestinal bleeding (36.9%) was the most common reason to stop aspirin in both groups. The primary endpoint is the composite of all-cause mortality, recurrent ACS or unplanned revascularization, and stroke within 12 months after discharge. The safety endpoint was the major bleeding defined as BARC 3 or 5 bleedings. The covariates were balanced between groups after using inverse probability of treatment weighting. Overall, 84 patients developed events of primary endpoint, with 57 (15.4%) in the clopidogrel group and 27 (11.2%) in the ticagrelor group. After multivariate adjustment in the Cox proportional-hazards models, ticagrelor was associated with a lower risk of primary endpoint compared with clopidogrel (adjusted hazard ratio [aHR] 0.67, 95% CI 0.49–0.93). Among the primary endpoint, ticagrelor significantly reduced the risk of recurrent ACS or unplanned revascularization (aHR 0.46, 95% CI 0.28–0.75). There was no significant difference of all-cause mortality between the 2 groups (aHR 0.92, 95% CI 0.52–1.61). The risk of BARC 3 or 5 bleeding was also similar (aHR 0.71, 95% CI 0.35–1.45).

Conclusions

Among ACS patients undergoing PCI who cannot tolerate aspirin, ticagrelor monotherapy was associated with a significantly lower risk of a composite of cardiovascular events compared to clopidogrel monotherapy. The major bleeding risk was similar between groups.

Funding Acknowledgement

Type of funding source: None

Identification, cloning, and recombinant expression of procalin, a major triatomine allergen

Among the most frequent anaphylactic reactions to insects are those attributed to reduviid bugs. We report the purification and identification of the major salivary allergen of these insects. This 20-kDa protein (procalin) is a member of the lipocalin family, which includes salivary allergens from other invertebrates and mammals. An expression system capable of producing reagent quantities of recombinant allergen was developed in Saccharomyces cerevisiae. Antisera produced against recombinant protein cross-reacts with ELISA with salivary allergen. Recombinant Ag is also shown to react with sera from an allergic patient but not with control sera. By immunolocalization, the source of the salivary Ag is the salivary gland epithelium and its secretions.

Schistosome invasion of human skin and degradation of dermal elastin are mediated by a single serine protease

Aquatic larvae (cercariae) of the trematode parasite Schistosoma mansoni rapidly penetrate human skin by degrading host proteins including elastin. Two serine proteases, one chymotrypsin-like and the second trypsin-like, have been proposed to be involved. To evaluate the relative roles of these two proteases in larval invasion, both were purified, identified by sequence, and then biochemically characterized. The trypsin-like activity was resolved into two distinct serine proteases 76% similar in predicted amino acid sequence. Southern blot analysis, genomic polymerase chain reaction, and immunolocalization demonstrated that the trypsin-like proteases are in fact not from the schistosome, but are released with larvae from the snail host Biomphalaria glabrata. Invasion inhibition assays using selective inhibitors confirmed that the chymotrypsin-like protease is the enzyme involved in skin penetration. Its ability to degrade skin elastin was confirmed, and the three sites of cleavage within elastin help define a new family of elastases.

Upregulation of the secretory pathway in cysteine protease inhibitor-resistant Trypanosoma cruzi

A novel chemotherapy in development for Chagas' disease targets cruzain, the major cysteine protease of Trypanosoma cruzi. Peptidomimetic inhibitors disrupt the intracellular cycle of the parasite and rescue animals from a lethal infection. Inhibitor killing of parasites results from interruption of autocatalytic cruzain processing and transport to lysosomes, and massive accumulation of precursor protein in the Golgi complex. To further understand the mechanisms of protease processing and transport in this primitive eukaryote, and uncover potential mechanisms for resistance to these drugs, we generated cysteine-protease inhibitor (CPI)-resistant epimastigotes in vitro and investigated the mechanisms involved at the biochemical and structural levels. Resistance to 20-fold the lethal CPI concentration, achieved after a year of gradual drug increase, was accompanied by a modest decrease in growth rate. A marked increase in the number of vesicles trafficking from the Golgi complex to the flagellar pocket occurs in resistant cells. No mature protease reaches lysosomes though accumulation of endocytosed gold particles in lysosomes appears to be normal. Higher molecular mass cruzain species, consistent with complexes of cruzain precursors and inhibitor, are secreted by CPI-resistant parasites into the culture supernatant. Release of these cruzain precursors may be facilitated by an enhanced acidification of trans-Golgi cisternae in resistant parasites. The pH within Golgi cisternae is higher in control epimastigotes and most mature cruzain is lysosomal. Cruzain activity is negligible in CPI-resistant epimastigote extracts compared to the parental clone. Activity is restored following withdrawal of the inhibitor. No cross-resistance to the therapeutic drugs nifurtimox and benznidazole occurred and, conversely, parasites resistant to these drugs were sensitive to CPI. Protease inhibitors are thus potential therapeutical alternatives in cases of nifurtimox/benznidazole resistance. Cumulatively, these results suggest that CPI-resistance induces upregulation of Golgi complex function and post-Golgi secretory pathway, and release of precursors before the enzyme reaches its site of biologic activity.

Cysteine protease inhibitors as chemotherapy: lessons from a parasite target

Papain family cysteine proteases are key factors in the pathogenesis of cancer invasion, arthritis, osteoporosis, and microbial infections. Targeting this enzyme family is therefore one strategy in the development of new chemotherapy for a number of diseases. Little is known, however, about the efficacy, selectivity, and safety of cysteine protease inhibitors in cell culture or in vivo. We now report that specific cysteine protease inhibitors kill Leishmania parasites in vitro, at concentrations that do not overtly affect mammalian host cells. Inhibition of Leishmania cysteine protease activity was accompanied by defects in the parasite's lysosome/endosome compartment resembling those seen in lysosomal storage diseases. Colocalization of anti-protease antibodies with biotinylated surface proteins and accumulation of undigested debris and protease in the flagellar pocket of treated parasites were consistent with a pathway of protease trafficking from flagellar pocket to the lysosome/endosome compartment. The inhibitors were sufficiently absorbed and stable in vivo to ameliorate the pathology associated with a mouse model of Leishmania infection.

Cysteine protease inhibitors cure an experimental Trypanosoma cruzi infection

Trypanosoma cruzi is the causative agent of Chagas' disease. The major protease, cruzain, is a target for the development of new chemotherapy. We report the first successful treatment of an animal model of Chagas' disease with inhibitors designed to inactivate cruzain. Treatment with fluoromethyl ketone-derivatized pseudopeptides rescued mice from lethal infection. The optimal pseudopeptide scaffold was phenylalanine-homophenylalanine. To achieve cure of infection, this pseudopeptide scaffold was incorporated in a less toxic vinyl sulfone derivative. N-methyl piperazine-Phe-homoPhe-vinyl sulfone phenyl also rescued mice from a lethal infection. Six of the treated mice survived over nine months, three without further treatment. Three mice that had entered the chronic stage of infection were retreated with a 20-d regimen. At the conclusion of the experiments, five of the six mice had repeated negative hemacultures, indicative of parasitological cure. Studies of the effect of inhibitors on the intracellular amastigote form suggest that the life cycle is interrupted because of inhibitor arrest of normal autoproteolytic cruzain processing at the level of the Golgi complex. Parasites recovered from the hearts of treated mice showed the same abnormalities as those treated in vitro. No abnormalities were noted in the Golgi complex of host cells. This study provides proof of concept that cysteine protease inhibitors can be given at therapeutic doses to animals to selectively arrest a parasitic infection.

Cysteine protease inhibitors alter Golgi complex ultrastructure and function in Trypanosoma cruzi

Cruzain, the major cysteine protease of the protozoan parasite Trypanosoma cruzi, is a target of rational drug design for chemotherapy of Chagas' disease. The precise biological role of cruzain in the parasite life cycle and the mechanism involved in the trypanocidal effect of cysteine protease inhibitors are still unclear. Here we report biological and ultrastructural alterations caused by cysteine protease inhibitors in T. cruzi epimastigotes. Cruzain, a glycoprotein that transits the Golgi-endosomal pathway, localized to pre-lysosomes/lysosomes in the posterior end of untreated epimastigotes by fluorescent microscopy utilizing either a biotinylated cysteine protease inhibitor to tag the active site, or a specific anti-cruzain antibody. Radiolabeled or biotinylated cysteine protease inhibitors bound exclusively to cruzain in intact epimastigotes confirming that cruzain is accessible to, and is targeted by the inhibitors. Treatment of T. cruzi epimastigotes with specific cysteine protease inhibitors arrested growth, altered the intracellular localization of cruzain, and induced major alterations in the Golgi complex. Following treatment, cruzain accumulated in peripheral dilations of Golgi cisternae. There was a concomitant 70% reduction in gold-labeled cruzain transported to lysosomes. Cisternae abnormalities in the Golgi compartment were followed by distention of ER and nuclear membranes. Brefeldin A increased the number and size of cisternae in epimastigotes. Pre-treatment of epimastigotes with cysteine protease inhibitors followed by exposure to brefeldin A induced a more rapid appearance of the cysteine protease inhibitor-induced Golgi alterations. Our results suggest that cysteine protease inhibitors prevent the normal autocatalytic processing and trafficking of cruzain within the Golgi apparatus. Accumulation of cruzain may decrease mobility of Golgi membranes and result in peripheral distention of cisternae. These major alterations of the Golgi complex parallel the death of T. cruzi epimastigotes.