Daptomycin Liposomes Exhibit Enhanced Activity against Staphylococci Biofilms Compared to Free Drug.

The purpose of the present study was to investigate the anti-staphylococcal activity of liposomal daptomycin against four biofilm-producing S. aureus and S. epidermidis clinical strains, three of which are methicillin-resistant. Neutral and negatively charged daptomycin-loaded liposomes were prepared using three methods, namely, thin-film hydration (TFH), a dehydration-rehydration vesicle (DRV) method, and microfluidic mixing (MM); moreover, they were characterized for drug encapsulation (EE%), size distribution, zeta-potential, vesicle stability, drug release, and drug integrity. Interestingly, whilst drug loading in THF and DRV nanosized (by extrusion) vesicles was around 30-35, very low loading (~4%) was possible in MM vesicles, requiring further explanatory investigations. Liposomal encapsulation protected daptomycin from degradation and preserved its bioactivity. Biofilm mass (crystal violet, CV), biofilm viability (MTT), and growth curve (GC) assays evaluated the antimicrobial activity of neutral and negatively charged daptomycin-liposomes towards planktonic bacteria and biofilms. Neutral liposomes exhibited dramatically enhanced inhibition of bacterial growth (compared to the free drug) for all species studied, while negatively charged liposomes were totally inactive. Biofilm prevention and treatment studies revealed high antibiofilm activity of liposomal daptomycin. Neutral liposomes were more active for prevention and negative charge ones for treating established biofilms. Planktonic bacteria as well as the matured biofilms of low daptomycin-susceptible, methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE) strains were almost completely eradicated by liposomal-daptomycin, indicating the need for their further exploration as antimicrobial therapeutics.

The Coadministration of Levosimendan and Exenatide Offers a Significant Cardioprotective Effect to Isolated Rat Hearts against Ischemia/Reperfusion Injury.

(1) Background: The present study aims to investigate the effect of administration of Levosimendan and Exenatide in various concentrations, as well as of the coadministration of those agents in an ischemia-reperfusion injury isolated heart model. (2) Methods: After 30 min of perfusion, the hearts underwent a 30 min period of regional ischemia followed by a 120 min period of reperfusion. All animals were randomly divided into 12 experimental groups of nine animals in each group: (1) Control, (2) Sham, (3) Digox (Negative control, Digoxin 1.67 µg/min), (4) Levo 1 (Levosimendan 0.01 µg/min), (5) Levo 2 (Levosimendan 0.03 µg/mL), (6) Levo 3 (Levosimendan 0.1 µg/min), (7) Levo 4 (Levosimendan 0.3 µg/min), (8) Levo 5 (Levosimendan 1 µg/min), (9) Exen 1 (Exenatide 0.001 µg/min), (10) Exen 2 (Exenatide 0.01 µg/min), (11) Exen 3 (Exenatide 0.1 µg/min) and (12) Combi (Levosimendan 0.1 µg/mL + Exenatide 0.001 µg/min). The hemodynamic parameters were recorded throughout the experiment. Arrhythmias and coronary flow were also evaluated. After every experiment the heart was suitably prepared and infarct size was measured. Markers of myocardial injury were also measured. Finally, oxidative stress was evaluated measuring reactive oxygen species. (3) Results: A dose-dependent improvement of the haemodynamic response was observed after the administration of both Levosimendan and Exenatide. The coadministration of both agents presented an even greater effect, improving the haemodynamic parameters further than the two agents separately. Levosimendan offered an increase of the coronary flow and both agents offered a reduction of arrhythmias. A dose-dependent reduction of the size of myocardial infarction and myocardial injury was observed after administration of Levosimendan and Exenatide. The coadministration of both agents offered a further improving the above parameters. Levosimendan also offered a significant reduction of oxidative stress. (4) Conclusions: The administration of Levosimendan and Exenatide offers a significant benefit by improving the haemodynamic response, increasing the coronary flow and reducing the occurrence of arrhythmias, the size of myocardial injury and myocardial oxidative stress in isolated rat hearts.

In vitro activity of dalbavancin and other anti-staphylococcal agents against infecting isolates of methicillin-resistant coagulase-negative staphylococci.

Introduction. Dalbavancin was approved in Europe in 2015 for skin and soft tissue infections.Hypothesis/Gap Statement. Data on methicillin-resistant coagulase-negative staphylococci (MR-CNS) dalbavancin susceptibility are scarce.Aim. To assess the susceptibility of MR-CNS to dalbavancin and other anti-staphylococcal agents.Methodology. A total of 443 MR-CNS clinical isolates from patients hospitalized in a Greek university hospital during a 2.5-year period (January 2018 to June 2020) were included. The MICs for vancomycin, teicoplanin, linezolid and daptomycin were investigated by Etest and the MIC for dalbavancin was determined according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines in 196 isolates. The consumption of the aforementioned antimicrobials was calculated.Results. In total, 51 isolates were resistant to teicoplanin (11.5 %) and 211 (47.6 %) to linezolid; all were susceptible to vancomycin and daptomycin. Among 196 isolates tested, 32 (16.3 %) were resistant to dalbavancin. A significant increase of MIC during the study period was found for vancomycin, teicoplanin and daptomycin, while a decrease in linezolid's MIC was observed. Dalbavancin's MIC remained stable. No difference in consumption was observed among the studied anti-staphylococcal agents.Conclusion. An increase of vancomycin, teicoplanin and daptomycin MICs among MR-CNS was observed, whereas 47.6 % of isolates were non-susceptible to linezolid. Dalbavancin retains excellent potency against MR-CNS, even in the presence of non-susceptibility to other anti-staphylococcal antibiotics.

In Vitro Anti-Biofilm Activity of Bacteriophage K (ATCC 19685-B1) and Daptomycin against Staphylococci.

The purpose of the present study was to investigate anti-staphylococcal activity of daptomycin and bacteriophage K, alone or in combination, against biofilm-producers and non-producers S. aureus and S. epidermidis strains, under biofilm forming and cells' proliferation conditions. Daptomycin and bacteriophage K (ATCC 19685B1), in different concentrations, were tested against 10 Staphylococcus aureus and 10 S. epidermidis, characterized by phenotypes and genotypes. The quantitative microtiter plate (crystal violet, CV), methylthiazoltetrazolium (MTT), and growth curve (GC) assays were performed. No statistically significant difference was found between species, whereas daptomycin alone performed better using medium and high concentrations of the drug and bacteriophage K was more active against strains with higher susceptibility, by CV and MTT assays. Best results were achieved using both agents combined in high concentrations. Bacteriophage K was effective within 3.8 and 2.4 h, depending on the concentration used, by the GC assay. Combination of daptomycin with bacteriophage K was more effective against staphylococci, depending on the concentrations used and strains' susceptibility. Further studies are needed to evaluate if this approach might be a choice for prevention or therapy of biofilm-associated infections.

Effect of Intravitreal Injection of Aflibercept on Cardiovascular Risk Parameters in Patients with Neovascular Age-Related Macular Degeneration.

OBJECTIVE: Systemic administration of anti-Vascular Endothelial Growth Factors (anti- VEGFs) has been associated with severe cardiovascular adverse events in oncologic patients. The purpose of this pilot study is to evaluate the short-term effect of a single intravitreal injection of aflibercept on biomarkers related to increased risk of cardiovascular disease. PATIENTS AND METHODS: Forty-seven treatment naïve patients with neovascular age-related macular degeneration in one eye were enrolled in the study. The patients underwent treatment with one intravitreal injection of aflibercept in the affected eye. Laboratory biomarkers of cardiovascular disease were evaluated before the first intravitreal injection of aflibercept and at 7 and 30 days after aflibercept administration. More precisely, we evaluated the levels of homocysteine, total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and Creactive protein. RESULTS: There was not any statistically significant change in the levels of the evaluated parameters up to one month after the first intravitreal injection of aflibercept. CONCLUSION: According to our study, the administration of a single dose of aflibercept in eyes with neovascular age-related macular degeneration does not seem to affect the evaluated biomarkers that are related to cardiovascular disease.

The "lively" cytokines network in beta-Thalassemia Major-related osteoporosis.

Osteoporosis affects approximately 40-50% of adult patients with beta-Thalassemia Major (beta TM). Recent data have implicated an altered modulation of the osteoprotegerin (OPG)/receptor activator of NFkB ligand (RANKL) system in the pathogenesis of beta TM-osteoporosis. OPG/RANKL system acts downstream from IL-1 alpha, IL-6 and TNF-alpha and it may be the final actor mediating the effects of these cytokines on the regulation of both postmenopausal and metabolic bone resorption. However, to date, there are no data on circulating levels of these pro-resorptive cytokines in beta TM patients. We investigated the potential relationships among these cytokines, several markers of bone turnover and bone mineral density (BMD) in beta TM patients. IL-1 alpha, IL-6 and TNF-alpha, OPG and RANKL serum levels, hemato-urinary bone remodeling markers and bone mineral density (BMD) at L2L4 and femoral neck as well as erythropoietin (EPO), 17beta-estradiol, and free-testosterone levels were measured in 30 well treated beta TM patients and in 20 healthy subjects, matched for age, sex and BMI with the patients. beta TM patients showed an altered bone turnover, with increased deoxypyridinoline (D-PYR) levels (P<0.0001), decreased osteocalcin (BGP) concentrations (<0.0001) and significantly lower lumbar (P=0.001) and femoral (P<0.05) BMD values as compared to controls. Circulating levels of IL-1 alpha (P<0.0001), TNF-alpha (P<0.0001) and IL-6 (P<0.05) were all increased in beta TM patients as compared with controls. In beta TM patients, IL-1 alpha was significantly related with D-PYR (r=0.5; P<0.05), RANKL (r=0.7; P=0.03) and IL-6 (r=0.3; P=0.006); IL-6 was also significantly correlated with D-PYR (r=0.5; P<0.05) and EPO levels (r=0.3; P=0.03); TNF-alpha showed a negative correlation with L2L4 BMD (r=-0.4; P<0.05). Our data demonstrate, for the first time, an association between increased circulating levels of pro-resorptive cytokines and an altered bone turnover in beta TM-patients, suggesting their involvement in the pathogenesis of beta TM-osteoporosis.