In vitro measurement of enzymatic markers as a tool to detect mouse cardiomyocytes injury

Mode of action of a novel anti-Listeria bacteriocin (CAMT2) produced by Bacillus amyloliquefaciens ZJHD3-06 from Epinephelus areolatus

Bacteriocin CAMT2, produced by Bacillus amyloliquefaciens ZJHD3-06, has been shown to exhibit protective activity against important food spoilage and food-borne bacterial pathogens. This study was conducted to investigate the mode of action of bacteriocin CAMT2 against highly pathogenic Listeria monocytogenes ATCC 19111. The addition of bacteriocin CAMT2 at 64 AU/ml inhibited L. monocytogenes ATCC 19111. An efflux of K⁺ ions, lactic acid dehydrogenase and an increase in extracellular electrical conductivity was observed in CAMT2-treated L. monocytogenes. Electron microscopy showed morphological alterations such as uneven cell surface, accumulation of cell debris and bacterial lysis. These results show that bacteriocin CAMT2 inhibit L. monocytogenes by increasing cell permeability and inducing membrane damage, hence it has the great application potentials in ensuring food safety.

Arylimidamide DB766, a potential chemotherapeutic candidate for Chagas' disease treatment

Chagas' disease, a neglected tropical illness for which current therapy is unsatisfactory, is caused by the intracellular parasite Trypanosoma cruzi. The goal of this work is to investigate the in vitro and in vivo effects of the arylimidamide (AIA) DB766 against T. cruzi. This arylimidamide exhibits strong trypanocidal activity and excellent selectivity for bloodstream trypomastigotes and intracellular amastigotes (Y strain), giving IC(50)s (drug concentrations that reduce 50% of the number of the treated parasites) of 60 and 25 nM, respectively. DB766 also exerts striking effects upon different parasite stocks, including those naturally resistant to benznidazole, and displays higher activity in vitro than the reference drugs. By fluorescent and transmission electron microscopy analyses, we found that this AIA localizes in DNA-enriched compartments and induces considerable damage to the mitochondria. DB766 effectively reduces the parasite load in the blood and cardiac tissue and presents efficacy similar to that of benznidazole in mouse models of T. cruzi infection employing the Y and Colombian strains, using oral and intraperitoneal doses of up to 100 mg/kg/day that were given after the establishment of parasite infection. This AIA ameliorates electrocardiographic alterations, reduces hepatic and heart lesions induced by the infection, and provides 90 to 100% protection against mortality, which is similar to that provided by benznidazole. Our data clearly show the trypanocidal efficacy of DB766, suggesting that this AIA may represent a new lead compound candidate to Chagas' disease treatment.

A translational study of circulating cell-free microRNA-1 in acute myocardial infarction

miRNAs (microRNAs) participate in many diseases including cardiovascular disease. In contrast with our original hypothesis, miRNAs exist in circulating blood and are relatively stable due to binding with other materials. The aim of the present translational study is to establish a method of determining the absolute amount of an miRNA in blood and to determine the potential applications of circulating cell-free miR-1 (microRNA-1) in AMI (acute myocardial infarction). The results revealed that miR-1 is the most abundant miRNA in the heart and is also a heart- and muscle-specific miRNA. In a cardiac cell necrosis model induced by Triton X-100 in vitro, we found that cardiac miR-1 can be released into the culture medium and is stable at least for 24 h. In a rat model of AMI induced by coronary ligation, we found that serum miR-1 is quickly increased after AMI with a peak at 6 h, in which an increase in miR-1 of over 200-fold was demonstrated. The miR-1 level returned to basal levels at 3 days after AMI. Moreover, the serum miR-1 level in rats with AMI had a strong positive correlation with myocardial infarct size. To verify further the relationship between myocardial size and miR-1 level, an IP (ischaemic preconditioning) model was used. The results showed that IP significantly reduced circulating miR-1 levels and myocardial infract size induced by I/R (ischaemia/reperfusion) injury. Finally, the levels of circulating cell-free miR-1 were significantly increased in patients with AMI and had a positive correlation with serum CK-MB (creatine kinase-MB) levels. In conclusion, the results suggest that serum miR-1 could be a novel sensitive diagnostic biomarker for AMI.