Methylene blue@silver nanoprisms conjugates as a strategy against Candida albicans isolated from balanoposthitis using photodynamic inactivation

Balanoposthitis can affect men in immunocompromised situations, such as HIV infection and diabetes. The main associated microorganism is Candida albicans, which can cause local lesions, such as the development of skin cracks associated with itching. As an alternative to conventional treatment, there is a growing interest in the photodynamic inactivation (PDI). It has been shown that the association of photosensitizers with metallic nanoparticles may improve the effectiveness of PDI via plasmonic effect. We have recently shown that the association of methylene blue (MB), a very known photosensitizer, with silver prismatic nanoplatelets (AgNPrs) improved PDI of a resistant strain of Staphylococcus aureus. To further investigate the experimental conditions involved in PDI improvement, in the present study, we studied the effect of MB concentration associated with AgNPrs exploring spectral analysis, zeta potential measurements, and biological assays, testing the conjugated system against C. albicans isolated from a resistant strain of balanoposthitis. The AgNPrs were synthesized through silver anisotropic seed growth induced by the anionic stabilizing agent poly(sodium 4-styrenesulfonate) and showed a plasmon band fully overlapping the MB absorption band. MB and AgNPrs were conjugated through electrostatic association and three different MB concentrations were tested in the nanosystems. Inactivation using red LED light (660 nm) showed a dose dependency in respect to the MB concentration in the conjugates. Using the highest MB concentration (100 µmol⋅L-1) with AgNPr, it was possible to completely inactivate the microorganisms upon a 2 min irradiation exposure. Analyzing optical changes in the conjugates we suggest that these results indicate that AgNPrs are enhancers of MB photodynamic action probably by a combined mechanism of plasmonic effect and reduction of MB dimerization. Therefore, MBAgNPrs can be considered a suitable choice to be applied in PDI of resistant microorganisms.

UV Light as an Efficient Tool for Reducing Surface Defects of ZnSe-MSA Quantum Dots

Defects in ZnSe quantum dots are responsible for increasing the trap states, which can lead to the drastic reduction of their fluorescence output, being one of the major drawbacks of these materials. As surface atoms become more relevant in these nanoscale structures, energy traps due to surface vacancies, play a very definite role in the final emission quantum yield. In the present study, we report the use of photoactivation procedures to decrease surface defects of ZnSe QDs stabilized with mercaptosuccinic acid (MSA), in order to improve the radiative pathways. We applied the colloidal precipitation procedure in a hydrophilic medium and evaluated the role of Zn/Se molar ratios as well as the Zn2+ precursors (nitrate and chloride salts) on their optical properties. Best results (i.e. increment of 400% of the final fluorescence intensity) were obtained for nitrate precursor and a Zn/Se = 1.2 ratio. Thus, we suggest that the chloride ions may compete more efficiently than nitrate ions with MSA molecules decreasing the passivation capability of this molecule. The improvement in ZnSe QDs fluorescence can potentialize their use for biomedical applications.

A fluorescent glyconanoprobe based on quantum dots and thiolated glucose: Applications in monolayers and spheroids of cancer cells

The differential energy metabolism of cancer cells has stimulated the development of tools that can be applied to better understand the complex biological interaction involved in the uptake of glucose analogs at the cellular level in this disease. Herein, we explored the outstanding optical properties of quantum dots (QDs) to develop a new fluorescent glyconanoprobe using the 1-thio-β-d-glucose (Glc). Then, monolayers and spheroids of HeLa cells were applied to probe the biological interaction with the conjugate through fluorescence techniques. Spheroids have been gaining prominence for better mimicking the tumor microenvironment. The Glc-QDs conjugate was prepared by a facile and direct procedure based on the affinity of the Glc thiol group by the QD semiconductor surface. The conjugation was evaluated and confirmed by Zeta potential (ζ) measurements, FTIR spectroscopy, and fluorescence correlation spectroscopy (FCS). Moreover, a biological assay using Candida albicans yeasts coated with concanavalin A, by exploring the lectin-carbohydrate affinity, was also developed to further confirm the conjugation, which corroborated the previous analyses. The hanging drop method was used to prepare the spheroids. The fluorescence microscopy analyses indicated an intracellular labeling by the glyconanoprobe, in both cell culture models. Flow cytometry assays revealed effective uptake of the conjugate (above ca. 76%), even by cells cultivated as spheroids, applying short incubation time. Therefore, a new fluorescent glyconanoprobe was developed, which showed potential to be applied for investigating mechanisms involved in the uptake of glucose analogs, both by simpler and complex cancer biological models, as monolayers and spheroids.

A fluorescent quantum dot conjugate to probe the interaction of Enterolobium contortisiliquum trypsin inhibitor with cancer cells

Serine proteases play crucial biological roles and have their activity controlled by inhibitors, such as the EcTI, a serine protease inhibitor purified from Enterolobium contortisiliquum seeds, which has anticancer activity. This study aimed to conjugate EcTI with quantum dots (QDs), fluorophores with outstanding optical properties, and investigate the interaction of QDs-EcTI nanoprobe with cancer cells. The conjugation was evaluated by fluorescence correlation spectroscopy (FCS) and fluorescence microplate assay (FMA). EcTI inhibitory activity after interaction with QDs was also analyzed. From FCS, the conjugate presented a hydrodynamic diameter about 4× greater than bare QDs, suggesting a successful conjugation. This was supported by FMA, which showed a relative fluorescence intensity of ca. 3815% for the nanosystem, concerning bare QDs or EcTI alone. The EcTI inhibitory activity remained intact after its interaction with QDs. From flow cytometry analyses, approximately 62% of MDA-MB-231 and 90% of HeLa cells were labeled with the QD-EcTI conjugate, suggesting that their membranes have different protease levels to which EcTI exhibits an affinity. Concluding, the QD-EcTI represents a valuable nanotool to study the interaction of this inhibitor with cancer cells using fluorescence-based techniques with the potential to unravel the intricate dynamics of interplays between proteases and inhibitors in cancer biology.

Strengthening collaborations at the Biology-Physics interface: trends in antimicrobial photodynamic therapy

The unbridled use of antimicrobial drugs over the last decades contributed to the global dissemination of drug-resistant pathogens and increasing rates of life-threatening infections for which limited therapeutic options are available. Currently, the search for safe, fast, and effective therapeutic strategies to combat infectious diseases is a worldwide demand. Antimicrobial photodynamic therapy (APDT) rises as a promising therapeutic approach against a wide range of pathogenic microorganisms. APDT combines light, a photosensitizing drug (PS), and oxygen to kill microorganisms by oxidative stress. Since the APDT field involves branches of biology and physics, the strengthening of interdisciplinary collaborations under the aegis of biophysics is welcome. Given this scenario, Brazil is one of the global leaders in the production of APDT science. In this review, we provide detailed reports of APDT studies published by the Laboratory of Optical Therapy (IPEN-CNEN), Group of Biomedical Nanotechnology (UFPE), and collaborators over the last 10 years. We present an integrated perspective of APDT from basic research to clinical practice and highlight its promising use, encouraging its adoption as an effective and safe technology to tackle important pathogens. We cover the use of methylene blue (MB) or Zn(II) porphyrins as PSs to kill bacteria, fungi, parasites, and pathogenic algae in laboratory assays. We describe the impact of MB-APDT in Dentistry and Veterinary Medicine to treat different infectious diseases. We also point out future directions combining APDT and nanotechnology. We hope this review motivates further APDT studies providing intuitive, vivid, and insightful information for the readers.

Emerging biomedical tools for biomarkers detection and diagnostics in schistosomiasis

Schistosomiasis is a neglected disease that strikes many people from tropical and subtropical countries where there are not satisfactory sanitation and wide access to clean water. Schistosoma spp., the causative agents of schistosomiasis, exhibit a quite complex life cycle that involves two hosts (humans and snails, respectively, the definitive and the intermediate), and five evolutive forms: cercariae (human infective form), schistosomula, adult worms, eggs, and miracidia. The techniques to diagnose schistosomiasis still have various limitations, mainly regarding low-intensity infections. Although various mechanisms associated with schistosomiasis have already been evidenced, there is still a need to fulfill the comprehension of this disease, especially to prospect for novel biomarkers to improve its diagnosis. Developing methods with more sensitivity and portability to detect the infection is valuable to reach schistosomiasis control. In this context, this review has gathered information not only on schistosomiasis biomarkers but also on emerging optical and electrochemical tools proposed in selected studies from about the last ten years. Aspects of the assays regarding the sensibility, specificity, and time needed for detecting diverse biomarkers are described. We hope this review can guide future developments in the field of schistosomiasis, contributing to improving its diagnosis and eradication.

New Insights in Phenothiazinium-Mediated Photodynamic Inactivation of Candida Auris

In recent years, Candida auris has emerged as a hazardous hospital-acquired pathogen. Its resistance to antifungal treatments makes it challenging, requiring new approaches to manage it effectively. Herein, we aimed to assess the impact of photodynamic inactivation mediated by methylene blue (MB-PDI) or 1,9-dimethyl MB (DMMB-PDI) combined with a red LED against C. auris. To evaluate the photoinactivation of yeasts, we quantified colony-forming units and monitored ROS production. To gain some insights into the differences between MB and DMMB, we assessed lipid peroxidation (LPO) and mitochondrial membrane potential (ΔΨm). After, we verified the effectiveness of DMMB against biofilms by measuring metabolic activity and biomass, and the structures were analyzed through scanning electron microscopy and optical coherence tomography. We also evaluated the cytotoxicity in mammalian cells. DMMB-PDI successfully eradicated C. auris yeasts at 3 μM regardless of the light dose. In contrast, MB (100 μM) killed cells only when exposed to the highest dose of light. DMMB-PDI promoted higher ROS, LPO and ΔΨm levels than those of MB. Furthermore, DMMB-PDI was able to inhibit biofilm formation and destroy mature biofilms, with no observed toxicity in fibroblasts. We conclude that DMMB-PDI holds great potential to combat the global threat posed by C. auris.

A Novel Strategy Based on Zn(II) Porphyrins and Silver Nanoparticles to Photoinactivate Candida albicans

Background

Photodynamic inactivation (PDI) is an attractive alternative to treat Candida albicans infections, especially considering the spread of resistant strains. The combination of the photophysical advantages of Zn(II) porphyrins (ZnPs) and the plasmonic effect of silver nanoparticles (AgNPs) has the potential to further improve PDI. Here, we propose the novel association of polyvinylpyrrolidone (PVP) coated AgNPs with the cationic ZnPs Zn(II) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin or Zn(II) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin to photoinactivate C. albicans.

Methods

AgNPs stabilized with PVP were chosen to allow for (i) overlap between the NP extinction and absorption spectra of ZnPs and (ii) favor AgNPs-ZnPs interaction; prerequisites for exploring the plasmonic effect. Optical and zeta potential (ζ) characterizations were performed, and reactive oxygen species (ROS) generation was also evaluated. Yeasts were incubated with individual ZnPs or their respective AgNPs-ZnPs systems, at various ZnP concentrations and two proportions of AgNPs, then irradiated with a blue LED. Interactions between yeasts and the systems (ZnP alone or AgNPs-ZnPs) were evaluated by fluorescence microscopy.

Results

Subtle spectroscopic changes were observed for ZnPs after association with AgNPs, and the ζ analyses confirmed AgNPs-ZnPs interaction. PDI using ZnP-hexyl (0.8 µM) and ZnP-ethyl (5.0 µM) promoted a 3 and 2 log₁₀ reduction of yeasts, respectively. On the other hand, AgNPs-ZnP-hexyl (0.2 µM) and AgNPs-ZnP-ethyl (0.6 µM) systems led to complete fungal eradication under the same PDI parameters and lower porphyrin concentrations. Increased ROS levels and enhanced interaction of yeasts with AgNPs-ZnPs were observed, when compared with ZnPs alone.

Conclusion

We applied a facile synthesis of AgNPs which boosted ZnP efficiency. We hypothesize that the plasmonic effect combined with the greater interaction between cells and AgNPs-ZnPs systems resulted in an efficient and improved fungal inactivation. This study provides insight into the application of AgNPs in PDI and helps diversify our antifungal arsenal, encouraging further developments toward inactivation of resistant Candida spp.

Fluorescent nanoprobes based on quantum dots conjugated to cramoll to assess surface carbohydrates of Aeromonas spp

The association of quantum dots (QDs) to carbohydrate-binding proteins - lectins - has revealed novel biotechnological strategies for glycobiology studies. Herein, carboxyl-coated QDs were conjugated by adsorption to Cramoll, a glucose/mannose lectin obtained from Cratylia mollis seeds. Then, the conjugates were optically characterized and used to evaluate the surface carbohydrate profiles of four Aeromonas species isolated from the tambaqui fish (Colossoma macropomum). All the Aeromonas cells were labeled by the conjugate. Inhibition assays with methyl-α-D-mannopyranoside and mannan were performed to confirm the labeling specificity. Cramoll-QDs conjugates presented high brightness and showed similar absorption and emission profiles compared to bare QDs. According to the labeling pattern of Aeromonas spp. by the conjugate, results suggested that A. jandaei and A. dhakensis strains may harbor a higher content of more complex glucose/mannose surface glycans, with more available sites for Cramoll-QDs interaction, than A. hydrophila and A. caviae. Noteworthy, the Cramoll-QDs conjugates demonstrated to be a potential tool for bacterial characterization based on superficial carbohydrate detection.

Optics in South America: introduction

South American optics research has seen remarkable growth over the past 50 years, with significant contributions in areas such as quantum optics, holography, spectroscopy, nonlinear optics, statistical optics, nanophotonics and integrated photonics. The research has driven economic development in sectors like telecom, biophotonics, biometrics, and agri-sensing. This joint feature issue between JOSA A and JOSA B exhibits cutting-edge optics research from the region, fostering a sense of community and promoting collaboration among researchers.

Advances in the study of spheroids as versatile models to evaluate biological interactions of inorganic nanoparticles

Spheroids are in vitro three-dimensional multicellular microstructures able to mimic the biological microenvironment, including the complexity of tumor architecture. Therefore, results closer to those expected for in vivo organisms can be reached using spheroids compared to the cell culture monolayer model. Inorganic nanoparticles (NPs) have also been playing relevant roles in the comprehension of biological processes. Moreover, they have been probed as novel diagnostic and therapeutical nanosystems. In this context, in this review, we present applications, published in the last five years, which show that spheroids can be versatile models to study and evaluate biological interactions involving inorganic NPs. Applications of spheroids associated with (i) basic studies to assess the penetration profile of nanostructures, (ii) the evaluation of NP toxicity, and (iii) NP-based therapeutical approaches are described. Fundamentals of spheroids and their formation methods are also included. We hope that this review can be a reference and guide future investigations related to this interesting three-dimensional biological model, favoring advances to Nanobiotechnology.

Acute ST-elevation myocardial infarction: are men and women particular cases of STEMI ?

Funding Acknowledgements

Type of funding sources: None.

Background

ST-segment elevation myocardial infarction (STEMI) has high levels of morbidity and mortality. Multiple risk factors may contribute to clinical outcomes and some studies demonstrate gender-related differences in baseline characteristics and in-hospital management.

Purpose

To access the difference in clinical characteristics and prognostic outcomes between men and women who were admitted in our Cardiac Intensive Care Unit with STEMI diagnosis.

Methods

We retrospectively analyzed 121 non-consecutive patients with STEMI during a mean follow-up period 135 ± 31 weeks.

We accessed baseline characteristics and time course of events (symptom onset-to-door admission; time to first EKG; time to fibrinolytic therapy; door-to-cath lab time and time from fibrinolytic therapy to PCI (for patients transferred from another centers).

Primary endpoint (PE) was a composite of in-hospital cardiovascular death, arrhythmic events or STEMI evolution in Killip-Kimbal III or IV.

Secondary endpoint (SE) was in-hospital major bleeding events, considered intracerebral hemorrhage, cases of hemodynamic compromise or requiring a blood transfusion.

Tertiary endpoint (TE) included admissions to the emergency department or hospitalization by heart failure decompensation, acute or chronic coronary syndromes and all-cause mortality.

Results

Of the 121 patients, 102 were male (84.3%) and 19 (15.7%) female. The mean age was 58.3 ± 12.7 years and women had a superior mean age (69.8 ± 12.2 years) vs. Men mean age 56 ± 11.6 years.

Hypertension was more prevalent in women (84.2% vs. 47.1%, respectively; p 0.003) and also diabetes – 36.8% of women had type 2 diabetes (vs 10.8% of men) and 5.3% of these female patients requires insulin therapy (vs 2% of men; p 0.021).

According to Charlson Comorbidity Index (CCI), women had a higher disease burden with 73.7% of them included into the moderate or severe group of mortality risk, compared to 42.2% of men (p 0.014).

Conversely, less women smoke (31.6% vs. 82.2%; p <0.001) and less frequently chest pain was the onset symptom (78.9% vs. 95.1%; p 0.04).

Time since symptom onset to door admission was estimated on 510 ± 1149 minutes and the mean women delay was superior (557 ± 858 minutes).

Regarding to in-hospital hemorrhagic events (secondary endpoint), female patients had a statistically significant higher risk (22.2% vs. 7.1%, p 0.045), independently of hypertension, diabetes or anticoagulant therapy (r=0.249; ANOVA p-value < 0.005), but it was associated with higher CCI (p 0.033). No other gender differences in outcomes or survival function were observed.

Conclusion

Our study demonstrates gender-related differences among patients with STEMI. Indeed, women were older, had more clinical cardiovascular risk factors and tend to delay hospital admission after symptoms onset. Secondary endpoint was statistically more frequent in women, but no other differences in outcomes were observed.

Aeromonas and Human Health Disorders: Clinical Approaches

The genus Aeromonas comprises more than 30 Gram-negative bacterial species and naturally inhabitants from aquatic environments. These microorganisms, commonly regarded as pathogens of fish and several other animals, have been gaining prominence on medical trial due to its ability to colonize and infect human beings. Besides water, Aeromonas are widely spreaded on most varied sources like soil, vegetables, and food; Although its opportunistic nature, they are able to cause infections on immunocompromised or immunocompetent patients. Aeromonas species regarded as potential human pathogens are usually A. hydrophila, A. caviae, and A. veronii biovar sobria. The main clinical manifestations are gastrointestinal tract disorders, wound, and soft tissue infections, as well as septicemia. Regarding to antibiotic responses, the bacteria present a diversified susceptibility profile and show inherence resistance to ampicillin. Aeromonas, as an ascending genus in microbiology, has been carefully studied aiming comprehension and development of methods for detection and medical intervention of infectious processes, not fully elucidated in medicine. This review focuses on current clinical knowledge related to human health disorders caused by Aeromonas to contribute on development of efficient approaches able to recognize and impair the pathological processes.

Photoinactivation of Yeast and Biofilm Communities of Candida albicans Mediated by ZnTnHex-2-PyP4+ Porphyrin

Candida albicans is the main cause of superficial candidiasis. While the antifungals available are defied by biofilm formation and resistance emergence, antimicrobial photodynamic inactivation (aPDI) arises as an alternative antifungal therapy. The tetracationic metalloporphyrin Zn(II) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (ZnTnHex-2-PyP⁴⁺) has high photoefficiency and improved cellular interactions. We investigated the ZnTnHex-2-PyP⁴⁺ as a photosensitizer (PS) to photoinactivate yeasts and biofilms of C. albicans strains (ATCC 10231 and ATCC 90028) using a blue light-emitting diode. The photoinactivation of yeasts was evaluated by quantifying the colony forming units. The aPDI of ATCC 90028 biofilms was assessed by the MTT assay, propidium iodide (PI) labeling, and scanning electron microscopy. Mammalian cytotoxicity was investigated in Vero cells using MTT assay. The aPDI (4.3 J/cm²) promoted eradication of yeasts at 0.8 and 1.5 µM of PS for ATCC 10231 and ATCC 90028, respectively. At 0.8 µM and same light dose, aPDI-treated biofilms showed intense PI labeling, about 89% decrease in the cell viability, and structural alterations with reduced hyphae. No considerable toxicity was observed in mammalian cells. Our results introduce the ZnTnHex-2-PyP⁴⁺ as a promising PS to photoinactivate both yeasts and biofilms of C. albicans, stimulating studies with other Candida species and resistant isolates.

Myracrodruon urundeuva leaf lectin damages exochorionic cells and binds to the serosal cuticle of Aedes aegypti eggs

In recent years, lectins have been identified as alternative agents against Aedes aegypti during the aquatic phases of its life cycle. For example, chitin-binding lectin from Myracrodruon urundeuva leaf (MuLL) can function as a larvicide. In this study, we investigated whether MuLL can also act as an ovicide against this insect. Aedes aegypti eggs were incubated with MuLL for 72 h to determine the concentration at which the hatching rate reduces by 50% (EC₅₀). The effects of MuLL on the egg surface structure were evaluated using scanning electron microscopy (SEM), and the possible interaction of MuLL with the internal structures of eggs and embryos was investigated using MuLL-fluorescein isothiocyanate (FITC) conjugate. MuLL acted as an ovicidal agent with an EC₅₀ of 0.88 mg/mL. The SEM analysis revealed that eggs treated with MuLL for 24 and 48 h no longer had tubercles and did not show a well-defined exochorionic network. In addition, deformation and degeneration of the surface were observed after 72 h. Fluorescence microscopy showed that MuLL penetrated the eggs 48 h after incubation and was detected in the upper portion of the embryo's gut. After 72 h, MuLL was observed in the serosal cuticle and digestive tract. In conclusion, MuLL can function as an ovicidal agent against A. aegypti through damage to the surface and internal structures of the eggs.

Mushrooms on the plate: Trends towards NAFLD treatment, health improvement and sustainable diets

Non-alcoholic fatty liver disease (NAFLD) is a most important cause of liver disease. Similar to other non-communicable diseases (NCD), such as obesity and type II diabetes mellitus, NAFLD can strongly affected by diet. Diet-related NCD and malnutrition are rising in all regions being a major cause of the global health, economic and environmental burdens. Mushrooms, important dietary components since the hunter-gathering communities, have increasingly gained momentum in biomedical research and therapeutics due to their interplay in metabolism traits. We emphasize here the beneficial effects of mushroom-enriched diets on the homeostasis of lipid and sugar metabolism, including their modulation, but also interfering with insulin metabolism, gut microbiota, inflammation, oxidative stress and autophagy. In this review, we describe the cellular and molecular mechanisms at the gut-liver axis and the liver-white adipose tissue (WAT) axis, that plausibly cause such positive modulation, and discuss the potential of mushroom-enriched diets to prevent or ameliorate NAFLD and related NCD, also within the shift needed towards healthy sustainable diets.

Mannose-binding lectin conjugated to quantum dots as fluorescent nanotools for carbohydrate tracing

Quantum dots (QDs) have stood out as nanotools for glycobiology due to their photostability and ability to be combined with lectins. Mannose-binding lectin (MBL) is involved in the innate immune system and plays important roles in the activation of the complement cascade, opsonization, and elimination of apoptotic and microbial cells. Herein, adsorption and covalent coupling strategies were evaluated to conjugate QDs to a recombinant human MBL (rhMBL). The most efficient nanoprobe was selected by evaluating the conjugate ability to labelCandida albicansyeasts by flow cytometry. The QDs-rhMBL conjugate obtained by adsorption at pH 6.0 was the most efficient, labelingca.100% of cells with the highest median fluorescence intensity. The conjugation was also supported by Fourier transform infrared spectroscopy, zeta potential, and size analyses.C. albicanslabeling was calcium-dependent; 12% and <1% of cells were labeled in buffers without calcium and containing EDTA, respectively. The conjugate promoted specific labeling (based on cluster effect) since, after inhibition with mannan, there was a reduction of 80% in cell labeling, which did not occur with methyl-α-D-mannopyranoside monosaccharide. Conjugates maintained colloidal stability, bright fluorescence, and biological activity for at least 8 months. Therefore, QDs-rhMBL conjugates are promising nanotools to elucidate the roles of MBL in biological processes.

Risk scores in predicting adverse events after an acute coronary syndrome

Funding Acknowledgements

Type of funding sources: None.

Introduction

ST-segment elevation myocardial infarction (STEMI) is a serious event that usually occur in patients with cardiovascular risk factors and is associated with great morbidity and mortality.

PARIS ischemic risk score and TIMI score were validated to evaluate ischemic risk in STEMI patients who underwent percutaneous coronary intervention (PCI) and to estimate mortality, respectively.

Despite these specific purposes, the usefulness of these scores in predicting adverse cardiovascular events (ACE) is unknown.

Objectives

To assess the prognostic value of PARIS and TIMI scores for cardiovascular events, coronary ischemic events and mortality in patients after STEMI.

Methods

Retrospective single center cohort study enrolled 103 patients with STEMI diagnosis between 2018 and 2019, during a mean follow-up period 30.30 ± 6.46 months and patients were included regardless of the reperfusion strategy.

Primary endpoint (PE) was a composite of acute coronary events (ACE), admissions to the emergency department by heart failure (HF) decompensation or chronic coronary syndrome and HF hospitalization. Secondary endpoint (SE) was ACE. Cardiovascular and non-cardiovascular death was determined.

PARIS ischemic risk score was calculated and patients were stratified into low (0-2), intermediate (3-4) or high (≥ 5) ischemic risk categories. TIMI score was also assessed.

Results

Out of 103 patients with STEMI diagnosis, the median age was 58.15 ± 12.6 years and 85,4% were male. Fifty-seven patients (55.3%) had hypertension, 45 (43.7%) dyslipidemia, 18 (17.5%) diabetes, 17 (15.5%) were obese and seventy-eight patients (75.7%) had history of smoking. Twenty (19.4%) patients had a previous acute coronary syndrome and 15 underwent PCI.

Twenty-five (24.3%) patients were included in low PARIS ischemic risk category, 53 (51.5%) in intermediate risk and 20 (19.4%) in high risk category.

PE occurred in 16 patient (15.5%) and SE in 7 patients (6.8%).

Eight patients died during the follow-up period (7.8%), 4 of cardiovascular causes (50%), 3 of non-cardiovascular causes (37.5%) and 1 of unknown cause.

PARIS ischemic risk score showed prognostic value for PE, with an area under the curve (AUC) of 0.65, 95% confidence interval (CI) 0.506-0.806 and p-value 0.039.

PARIS score also had predictive value for SE (AUC 0.816, 95% CI 0.604-1.000; p 0.004) as well as TIMI score (AUC 0.738, 95% CI 0.560 – 0.917; p 0.032).

Both scores showed a good prognostic value in evaluating all-cause mortality, with a slightly better predictive value for TIMI score (AUC 0.91, 95% CI 0.802 – 1.00) when compared to PARIS score (AUC 0.84, 95% CI 0.685 – 0.987).

Conclusion

This study revealed that PARIS and TIMI scores have a good discriminatory power to predict prognosis in STEMI patients. According to our study results, these scores could be an interesting tool to determine the likelihood of fatal and non-fatal outcomes, including ACS.

Hemorrhagic risk scores in hospitalized patients with acute coronary syndrome: can they (only) predict bleeding events?

Funding Acknowledgements

Type of funding sources: None.

Introduction

Acute coronary syndrome (ACS) is a life-threatening condition and its therapeutic approach increases the risk of important bleeding events which are associated with a worse prognosis. Along with hemorrhagic events, a drop on hemoglobin level not related to bleeding or the development of anemia could have a negative impact on prognosis.

Both CRUSADE and PARIS bleeding risk scores are used to evaluate and to stratify the risk of major bleeding in ACS. However their actual predictive value has been questioned and validity of these scores in predicting in-hospital mortality (IHM) is not established.

Objectives

To evaluate the actual prognostic value of CRUSADE and PARIS bleeding scores in ACS patients during their hospitalization stay.

Methods

Retrospective single center cohort study including 103 hospitalized patients after an acute ST-segment elevation myocardial infarction (STEMI) regardless of its reperfusion strategy.

In-hospital major hemorrhagic events (IHMHE), considered intracerebral hemorrhage, those resulting in hemodynamic compromise or requiring a blood transfusion, were assessed. Data on hemoglobin levels (HL) at hospital admission and at the time of hospital discharge were also collected and a composite endpoint (CE) of IHMHE and a drop in HL  ≥ 3g/dL were elaborated.

Both scores were calculated for each patient, its predictive value and their impact on IHM were determined.

Results

Out of 103 patients enrolled, the median age was 58.15 ± 12.6 years and 85.4% were male.

Two IHMHE occurred, twenty patients (19.4%) had anemia at the time of hospital discharge and 16 of these patients (15.5%) were not anemic at the time of hospital admission. Nine (8.7%) patients had a drop in their HL of at least 3g/dL.

The five bleeding risk categories defined by CRUSADE investigators were used, with 48 (46.6%) patients in the very low risk category, 9 (8.7%) and 6 (5.8%) in the high and very high risk category, respectively.

Hospitalization length stay was 5.6 ± 4.1 days with an overall in-hospital mortality (IHM) of 5.8%.

Receiver operating characteristic curve (ROC) analysis showed that CRUSADE score had an excellent discriminatory power for the CE (AUC 0.927, 95% CI 0.854-1.000) and the PARIS score had an acceptable discriminatory value (AUC 0.775, 95% CI 0.616-0.935).

Both CRUSADE and PARIS bleeding scores also had prognostic value in evaluating IHM (AUC 0.929, 95% CI 0.856-1.000 and AUC 0.788, 95% CI 0.634-0.942, respectively).

No specific and independent predictors of IHMHE were found, neither related to individual characteristics nor to therapeutic approach.  

Conclusion

The presenting study showed that CRUSADE and PARIS scores still have discriminatory power to assess CE and to assess IHM in ACS patients. Their addition to stratification tools could be of interest.

New Insights into Hemolytic Anemias: Ultrastructural and Nanomechanical Investigation of Red Blood Cells Showed Early Morphological Changes

Several diseases are characterized by changes in the mechanical properties of erythrocytes. Hemolytic anemias are an example of these diseases. Among the hemolytic anemias, Sickle Cell Disease and Thalassemia are the most common, characterized by alterations in the structure of their hemoglobin. Sickle cell disease has a pathological origin in synthesizing abnormal hemoglobin, HbS. In contrast, thalassemia results in extinction or decreased synthesis of α and β hemoglobin chains. This work presents a detailed study of biophysical and ultrastructural early erythrocytes membrane alterations at the nanoscale using Atomic Force Microscopy (AFM). Cells from individuals with sickle cell anemia and thalassemia mutations were studied. The analysis methodology in the AFM was given by blood smear and exposure of the inner membrane for ghost analysis. A robust statistic was used with 65,536 force curves for each map, ten cells of each type, with three individuals for each sample group. The results showed significant differences in cell rigidity, adhesion, volume, and roughness at early morphological alterations, bringing new perspectives for understanding pathogenesis. The sickle cell trait (HbAS) results stand out. Significant alterations were observed in the membrane properties, bringing new perspectives for the knowledge of this mutation. This work presents ultrastructural and biomechanical signatures of sickle cell anemia and thalassemia genotypes, which may help determine a more accurate biophysical description and clinical prognosis for these diseases.

Synthesis of hydrophilic Ag2Se quantum dots optically optimized by multivariate strategies: an easy one-pot approach

A simple and fast aqueous synthesis of silver selenide quantum dots is proposed with the aid of multivariate optimization.

Analyses of the response of carbapenem-resistant Pseudomonas aeruginosa against monotherapy and combined therapy using quantum dots and proteomics

Carbapenem-resistant P. aeruginosa (CRPA) has become a serious public health problem and the biofilm formation aggravates this problem. The study aimed to evaluate the occurrence of β-lactamases and quorum sensing (QS) genes in CRPA isolates, analyze production of biofilm, evaluate the response against meropenem (MPM) and∕or polymyxin B (POL B) and its association with azythromicin (AZT) using quantum dots (QDs) and proteomic analysis. Six CRPA isolates were analyzed. β-lactamases and QS genes were search using specific PCRs and were tested for biofilm production by quantitative technique. A CRPA isolate, containing blaKPC gene and biofilm-producing, was selected to assess its response to therapy using QDs and the MALDI-TOF. The β-lactamase detected was blaKPC in 66.7% of the isolates. All isolates were biofilm producers and carriers of the QS genes. QDs-MPM conjugates triggered the formation of biofilm and the association with AZT inhibited this effect. Proteomics analysis showed that treatments with MPM or POL B suppressed the expression of the transglycosylase protein, while combined therapy with AZT induced expression of the RpoN protein. Thus, this study shows that the use of fluorescence combined with the proteomics analysis was promising to understand how a CRPA strain reacts to antimicrobial treatment.

Quantum dots conjugated to lectins from Schinus terebinthifolia leaves (SteLL) and Punica granatum sarcotesta (PgTeL) as potential fluorescent nanotools for investigating Cryptococcus neoformans

This study reports the development of conjugates based on quantum dots (QD)s and lectins from Schinus terebinthifolia leaves (SteLL) and Punica granatum sarcotesta (PgTeL). Cryptococcus neoformans cells were chosen to evaluate the efficiency of the conjugates. Lectins were conjugated to QDs via adsorption, and the optical parameters (emission and absorption) were monitored. Lectin stability in the conjugates towards denaturing agents was investigated via fluorometry. The conjugation was evaluated using fluorescence microplate (FMA) and hemagglutination (HA) assays. The labeling of the C. neoformans cell surface was quantified using flow cytometry and observed via fluorescence microscopy. The QDs-SteLL and QDs-PgTeL conjugates, obtained at pH 7.0 and 8.0, respectively, showed the maintenance of colloidal and optical properties. FMA confirmed the conjugation, and the HA assay indicated that the lectin carbohydrate-binding ability was preserved after conjugation. SteLL and PgTeL showed stability towards high urea concentrations and heating. Conjugates labeled over 90% of C. neoformans cells as observed via flow cytometry and confirmed through fluorescence microscopy. C. neoformans labeling by conjugates was inhibited by glycoproteins, suggesting specific interactions through the lectin carbohydrate-binding site. Thus, an effective protocol for the conjugation of SteLL or PgTeL with QDs was proposed, yielding new nanoprobes useful for glycobiological studies.

STEMI treatment in remote areas – challenges of the only interventional angioplasty center located in an archipelago

Background

In remote islands lack of specialized medical facilities, long distance transfer and emergency medical system organization remains a challenge and fibrinolysis is necessary to achieve revascularization in optimal timing in ST-elevation myocardial infarction (STEMI) patients. Our angioplasty center is the only one located in an archipelago composed of nine islands, six of which do not have hospital facilities and only have small family health care units.

Purpose

To evaluate the reality and outcomes of our interventional angioplasty center and compare cardiovascular outcomes between STEMI patients from the main island and remote islands.

Methods

We retrospectively evaluated 103 patients with STEMI admitted to our center between 2018 and 2019. Patients from the main island where the center is located underwent primary percutaneous coronary intervention (PCI) (group 1, n=55) and patients from remote islands underwent fibrinolytic therapy followed by transference to our center with facilitated or rescue PCI (group 2, n=48). A subanalysis of the far remote islands without hospital facilities was also performed. Primary outcome was defined as cardiovascular death or re-infarction at two years and secondary outcome as intrahospital haemorrhagic complications.

Results

Mean age was 58,15±12,6 years, 85,4% were males and follow up period was 30,30±6,46 months. Seventy-eight patients (75,7%) had history of smoking, 45 (43,7%) dyslipidemia, 20 (19,4%) previous acute coronary syndrome, 18 (17,5%) diabetes and 17 (15,5%) were obese. Troponin I peak was 117,42±129,06 ug/L and 14 (13,6%) were in Killip Class III/IV. Infarct-related artery was the left anterior descending artery in 45 (45,5%) and multivessel disease was present in 38 (38,0%). In group 1 reperfusion after PCI was obtained in 91,5%. In group 2, 73,5% met criteria for reperfusion after fibrinolysis and 23,6% after rescue PCI. Mean time from fibrinolysis to PCI was 558±349 minutes. Rates of successful revascularization did not differ between groups, as well as complete patency of the culprit-vessel defined as thrombolysis in myocardial infarction (TIMI) flow 3 (91,5% vs. 97,2% and 90,0% vs. 93,0% respectively for group 1 and 2). Cardiovascular death at two years occurred in 4 (3,9%) patients and re-infarction in 11 (10,7%) and were similar between groups (3 (5,5%) vs. 1 (2,1%) and 8 (14,5%) vs. 3 (6,3%) respectively) as well as haemorrhagic complications (1 (1,8%) vs. 5 (10,4%) respectively). Nineteen (18,4%) patients were from far remote islands without hospital facilities and when comparing these patients with the others there was also no difference in primary outcome.

Conclusion

Even in remote islands, an organized STEMI network with attempted fibrinolytic treatment and coordinated transference of patients for facilitated or rescue PCI can provide successful revascularization with cardiovascular outcomes similar to those submitted to primary PCI.

Funding Acknowledgement

Type of funding sources: None.

Early and long term prognostic accuracy of 4 acute pulmonary embolism mortality risk scores

Background

Acute pulmonary embolism (PE) is a frequent condition associated with significant morbidity and mortality. Multiple scores have been developed and validated to predict 30-day mortality risk, however accurate prognostic assessment remains a challenge in clinical practice.

Purpose

To compare the performance of PESI, simplified PESI, Hestia and Bova scores in predicting in-hospital, 30-day and 1-year mortality risk for acute PE.

Methods

We retrospectively assessed consecutive patients from a single center registry who were hospitalized with acute PE between January 2017 and October 2020. Discriminative power of each score was assessed by receiver operating characteristic curve analysis. Charlson comorbidity index (CCI) was also assessed for comparison.

Results

A total of 131 patients with a mean age of 67.6±15.3 years were included with a mean follow-up of 46.3±17.7 months. Thirty-six patients (27.5%) had a recent hospitalization or major surgery and 26 (19.8%) a medical history of cancer. Besides anticoagulation, 7 patients (5.3%) underwent fibrinolysis. Overall in-hospital mortality was 8.4%, 30-day mortality 12.2% and 1-year mortality 19.8%. All acute PE scores, except Bova score, were significantly higher in those patients who died during hospitalization and on 30-day and 1-year follow-up. CCI was also higher in those patients. Discriminative power for in-hospital mortality was higher for PESI (c-statistic 0.84, 95% CI 0.74–0.93, p=0.002), followed by sPESI (c-statistic 0.77, 95% CI 0.65–0.90, p=0.010) and Hestia (c-statistic 0.77, 95% CI 0.61–0.92, p=0.011). The Bova score showed a poor discriminative power for prediction of in-hospital mortality (c-statistic 0.61, 95% CI 0.43–0.78, p=0.325). For 30-day and 1-year mortality PESI score still maintained the best performance with acceptable discriminative power (c-statistic 0.73, 95% CI 0.61–0.85, p=0.007 for 30-day mortality; c-statistic 0.80, 95% CI 0.71–0.89, p&lt;0.0001 for 1-year mortality). However at longer follow-up CCI had a better performance to predict worse outcomes (c-statistic 0.79, 95% CI 0.65–0.92, p=0.001 for 30-day mortality; c-statistic 0.83, 95% CI 0.74–0.92, p&lt;0.0001 for 1-year mortality).

Conclusions

All scores, except Bova score, showed overall good performance in stratifying mortality for acute PE, however PESI score performed better in this population particularly at shorter follow-up. At longer follow-up, although PESI score maintained an acceptable performance, comorbidities seem to play a bigger role. The different performance of multiple scores highlights the complexity of this condition.

Funding Acknowledgement

Type of funding sources: None. ROC curves for mortality risk scores

New York Heart Association class change on heart failure patients with implantable devices: does it matters?

Background

Chronic heart failure (CHF) is a pathology with high prevalence and an important cause of morbidity and mortality. Benefits of implantable devices have been demonstrated in selected groups of patients with benefits on symptoms and heart failure hospitalization.

Purpose

To determine the clinical impact of New York Heart Association class change (NYHA) in patients with CHF and Cardiac Implantable Electric Devices (CIEDs).

Methods

We retrospectively enrolled 178 consecutive patients with CHF and CIEDs between November 2003 and January 2021, during a follow-up period of 51±43,9 months. Patients demographic characteristic and NYHA class change impact on occurrence of arrhythmic events, heart failure hospitalization (HFH) or long-term admission in an emergency department were assessed. Patients with NYHA class change were considered responders to therapy.

Results

Out of 178 patients enrolled in this study, sixty-seven (37,6%) had a reduction ≥1 in NYHA functional class and in this group, 61 patients (91,0%) had a cardiac resynchronization therapy (CRT) and 9% had an implantable cardioverter defibrillator. Mean age 68±11,3 years, 44 (65,7%) patients were male, 33 (49,2%) were in NYHA class II, 30 (44,8%) NYHA class III and 4 (6%) NYHA class IV. Mean QRS width 129,9±63,1 ms before CIEDs. Fifty-eight patients (86,6%) had an improvement in one NYHA functional class and 9 patients (13,4%) in two NYHA functional class.

Fourty NYHA responders patients (59,7%) had paroxistic or permanent atrial fibrillation and 31,9% had an epicardial coronary artery disease, that was a negative predictor of NYHA response (p=0,012).

A total of 35 (19,7%) enrolled patients experience non-sustained ventricular tachycardia (NSVT) and 74,3% were non-responders (p=0,019).

There was fifteen and twenty HFH at 2 and 5 years of follow-up, respectively, and we observed that an improvement in NYHA class was associated with a reduction in HFH at 2 years of follow-up (p=0,043; OR 0,029, 95% CI 0,050–1,06) and 5 years of follow-up (p 0,027, OR 0,252; 95% CI 0,069 – 0,915). Emergency department (ED) admission related to HF decompensations was significantly reduced at 2 years of follow-up (p=0,035, OR 0,22, 95% CI 0,048 – 1,0) and at 5 years of follow-up (p=0,001, OR 0,15, 95% CI 0,044 – 0,55).

There was no difference on cardiovascular or all-cause mortality.

Conclusion

CHF patients with CIEDs and improving on NYHA class have less NSVT episodes, HFH and HF decompensations with ED admission, both at 2 and 5 years of follow-up.

Funding Acknowledgement

Type of funding sources: None.

Non-sustained ventricular tachycardia on remote patient monitoring in heart failure patients

Background

Non-sustained ventricular tachycardia (NSVT) is commonly found in patients with structural heart disease and was historically obtained from registers of external ambulatory monitoring. The advent of remote patient monitoring (RPM) in Cardiac implantable electronic devices (CIEDs) has made it possible to detect asymptomatic NSVT in Heart Failure (HF) patients more frequently, but its impact in real world is uncertain.

Purpose

To determine the clinical impact of NSVT detection in RPM in ischemic and non-ischemic chronic heart failure patients with reduced ejection fraction (HFrEF) and CIEDs.

Methods

We retrospectively enrolled 121 consecutive patients with HFrEF, CIEDs and RPM. Patients were evaluated through routine episodic CIEDs interrogation, routine clinical evaluations and continuous monitoring data obtained from CIEDs and transmitted remotely to the care team and divided into NSVT positive (Group 1) and negative groups (Group 2). Primary endpoint was admissions to the emergency department by HF decompensation and secondary endpoint was the occurrence of arrhythmic events. A sub-analysis of non-ischemic HF was also performed.

Results

NSVT was detected in 78 (72,2%) patients. The mean number of episodes of NSVT was 611,68±3271,25 during the follow-up period or 2,445±16,688 in 24 hours. Mean age was 62,40±13,218 years, 71,9% were males and mean follow-up period was 56,30±39,37 months. Fifty-eight patients (47,9%) had transvenous implantable cardioverter defibrillator (ICD), 48 (39,7%) implantable cardiac resynchronization therapy (CRT) defibrillator (CRT-D), 14 (11,6%) subcutaneous ICD (S-ICD) and 1 (0,8%) CRT pacemaker (CRT-P). Medium left ventricular ejection fraction (LVEF) was 34,70±12,53%, 25 (23,14%) were in NYHA III-IV and 46 (39,0%) were ischemic (29 (37,7%) in Group 1 and 11 (37,9%) in Group 2). NSVT was associated with the occurrence of sustained ventricular tachycardia (VT) (1,88±0,186episodes of VT in group 1 and 0,03±0,186 in group 2, p=0,012), ventricular fibrillation (VF) (1,44±5,325 episodes of VT in group 1 and 0,03±0,186 in group 2, p=0,011) and admissions to the emergency department by HF decompensation at 5 years (r=0,310, p=0,011). A sub-analysis in non-ischemic HF patients also showed correlation between NSVT and VT (r=0,602, p&lt;0,05) and admissions to the emergency department by HF decompensation at 5 years (r=0,382, p=0,014).

Conclusions

On remote patient monitoring with CIEDs, NSVT in HF patients was associated with arrhythmic events and may serve as a predictor for HF decompensations.

Funding Acknowledgement

Type of funding sources: None.

Prognostic significance of non-sustained ventricular tachycardia on stored electrograms of heart failure patients with cardiovascular implantable electronic devices

Background

Non-sustained ventricular tachycardia (NSVT) is commonly found in patients with structural heart disease and was historically obtained from registers of external ambulatory monitoring. The advent of Cardiac implantable electronic devices (CIEDs) has made it possible to detect asymptomatic NSVT in Heart Failure (HF) patients more frequently, but its true impact in real world is uncertain, and often does not lead to a change in clinical intervention.

Purpose

To determine the prognostic significance of NSVT detection on stored electrograms of CIEDs in HF patients with systolic left ventricle dysfunction.

Methods

We retrospectively enrolled 132 consecutive HF patients (mean age 67,5±11,1 years, males 72,0%) with systolic left ventricle dysfunction and CIEDs (biventricular pacemakers with or without cardiac defibrillators). Patients were evaluated through CIEDs interrogation and clinical evaluations and divided into NSVT positive (Group 1) and negative groups (Group 2). Mean follow-up period was 62,8±7,1 months.

Results

NSVT was detected in 51 (38,6%) patients. 70 (53,0%) had implantable cardiac resynchronization therapy (CRT) defibrillator (CRT-D), 37 (28,0%) transvenous implantable cardioverter defibrillator (ICD), 13 (9,8%) CRT pacemaker (CRT-P) and 12 (9,1%) subcutaneous ICD (S-ICD). Medium left ventricular ejection fraction (LVEF) was 31,1±7,9%, 20,6% were in NYHA III-IV and 47,0% were ischemic (49% Group 1 and 45,7% Group 2, p=0,708). Dyslipidemia was more prevalent in Group 2 (p=0,042). In total 11 (8,3%) patients died, 2 (1,5%) from sudden cardiac death and 5 (3,8%) from cardiovascular death. NSVT was associated with CIEDs treatments (hazard ratio [HR]2,52; 95% confidence interval [CI]1,2–5,1; p=0,001), ventricular fibrillation (VF) (HR: 3,71, 95% CI: 1,19–11,58; p=0,018), sustained ventricular tachycardia (VT) (HR: 9,06, 95% CI: 2,82–29,12; p&lt;0,05) and composite outcome of VT, VF, HF re-admissions and related admissions to emergency department (ED) and death by all causes (HR: 2,52; 95% CI: 1,20–5,10; p=0,011). NSVT at 1 year was associated with HF readmissions at 1 year (p=0,004).

Conclusions

On extended monitoring possible with CIEDs, NSVT in HF patients was associated with a worse prognosis and may serve as a predictor of significant arrhythmic events, HF hospitalizations and mortality. These findings enhances the importance of remote monitoring and optimization of therapeutic modalities in these patients along with a close supervision.

Funding Acknowledgement

Type of funding sources: None.

Silver nanoprisms as plasmonic enhancers applied in the photodynamic inactivation of Staphylococcus aureus isolated from bubaline mastitis

Mastitis is a bacterial infection that affects all lactating mammals, and in dairy cattle, it leads to a reduction in their milk production and, in worse cases, it may lead to animal death. One viable therapeutic modality for overcoming bacterial resistance can be photodynamic inactivation (PDI), a therapeutic modality for bacterial infection treatment. One of the main factors that can lead to an efficient PDI process is the association of metallic nanoparticles in the close vicinity of photosensitizers, which has shown promising results due to localized surface plasmon resonance phenomena. In this work, methylene blue (MB) molecules were associated with Ag prismatic nanoplatelets (AgNPrs) to use as PDI photosensitizer against Staphylococcus aureus isolated from bubaline mastitis. The optical plasmonic activity of AgNPrs was tuned to the MB absorption region (600-700 nm) by inducing their growth into prismatic shapes by a seed-mediated procedure, using poly (sodium 4-styrene sulfonate) as the surfactant. A simulation on the plasmonic properties of the nanoprisms, applying particle size within the dimensions determined by TEM image analysis (d = 32 ± 6 nm), showed a 30 % increase of the incident field on the prismatic tips. Photodynamic results showed that the electrostatic AgNPr-MB conjugates promoted enhancement (ca. 15 %) of the reactive oxygen species production. Besides, PDI mediated by AgNPrs-MB led to the complete inactivation of the mastitis S. aureus strain after 6 min inactivation, in contrast to PDI mediated by MB, which reduced less than a 0.5 bacterial log. Thus, the results show this plasmonic enhanced photodynamic tool's potential to be applied in the inactivation of multi-resistant bacterial strains.

Efficient photodynamic inactivation of Leishmania parasites mediated by lipophilic water-soluble Zn(II) porphyrin ZnTnHex-2-PyP4

BACKGROUND

Photodynamic inactivation (PDI) is emerging as a promising alternative for cutaneous leishmaniasis (CL). The chemotherapy currently used presents adverse effects and cases of drug resistance have been reported. ZnTnHex-2-PyP⁴⁺ is a porphyrin with a high potential as a photosensitizer (PS) for PDI, due to its photophysical properties, structural stability, and cationic/amphiphilic character that can enhance interaction with cells. This study aimed to investigate the photodynamic effects mediated by ZnTnHex-2-PyP⁴⁺ on Leishmania parasites.

METHODS

ZnTnHex-2-PyP⁴⁺ stability was evaluated using accelerated solvolysis conditions. The photodynamic action on promastigotes was assessed by (i) viability assays, (ii) mitochondrial membrane potential evaluation, and (iii) morphological analysis. The PS-promastigote interaction was studied. PDI on amastigotes and the cytotoxicity on macrophages were also analyzed.

RESULTS

ZnTnHex-2-PyP⁴⁺, under submicromolar concentration, led to immediate inactivation of more than 95% of promastigotes. PDI promoted intense mitochondrial depolarization, loss of the fusiform shape, and plasma membrane wrinkling in promastigotes. Fluorescence microscopy revealed a punctate PS labeling in the parasite cytoplasm. PDI also led to reductions of ca. 64% in the number of amastigotes/macrophage and 70% in the infection index after a single treatment session. No noteworthy toxicity was observed on mammalian cells.

CONCLUSIONS

ZnTnHex-2-PyP⁴⁺ is stable against demetallation and more efficient as PS than the ethyl analogue ZnTE-2-PyP⁴⁺, indicating readiness for evaluation in in vivo studies as an alternative approach to CL.

GENERAL SIGNIFICANCE

This report highlighted promising photodynamic effects mediated by ZnTnHex-2-PyP⁴⁺ on Leishmania parasites, opening up perspectives for applications in CL pre-clinical assays and PDI of other microorganisms.

Quantum Dots and Gd3+ Chelates: Advances and Challenges Towards Bimodal Nanoprobes for Magnetic Resonance and Optical Imaging

The development of multimodal nanoprobes has been growing in recent years. Among these novel nanostructures are bimodal systems based on quantum dots (QDs) and low molecular weight Gd³⁺ chelates, prepared for magnetic resonance imaging (MRI) and optical analyses. MRI is a technique used worldwide that provides anatomic resolution and allows distinguishing of physiological differences at tissue and organ level. On the other hand, optical techniques are very sensitive and allow events to be followed at the cellular or molecular level. Thus, the association of these two techniques has the potential to achieve a more complete comprehension of biological processes. In this review, we present state-of-the-art research concerning the development of potential multimodal optical/paramagnetic nanoprobes based on Gd³⁺ chelates and QDs, highlighting their preparation strategies and overall properties.

Methods for Intracellular Delivery of Quantum Dots

Quantum dots (QDs) have attracted considerable attention as fluorescent probes for life sciences. The advantages of using QDs in fluorescence-based studies include high brilliance, a narrow emission band allowing multicolor labeling, a chemically active surface for conjugation, and especially, high photostability. Despite these advantageous features, the size of the QDs prevents their free transport across the plasma membrane, limiting their use for specific labeling of intracellular structures. Over the years, various methods have been evaluated to overcome this issue to explore the full potential of the QDs. Thus, in this review, we focused our attention on physical and biochemical QD delivery methods-electroporation, microinjection, cell-penetrating peptides, molecular coatings, and liposomes-discussing the benefits and drawbacks of each strategy, as well as presenting recent studies in the field. We hope that this review can be a useful reference source for researches that already work or intend to work in this area. Strategies for the intracellular delivery of quantum dots discussed in this review (electroporation, microinjection, cell-penetrating peptides, molecular coatings, and liposomes).

A facile route toward hydrophilic plasmonic copper selenide nanocrystals: new perspectives for SEIRA applications

Development of versatile and efficient plasmonic nanoprobes for detection of (bio)molecules in an ultrasmall concentration, when applied as substrates in surface-enhanced infrared (SEIRA) spectroscopy.

Activity of carbonyl cyanide-3-chlorophenylhydrazone on biofilm formation and antimicrobial resistance in Pseudomonas aeruginosa using quantum dots-meropenem conjugates as nanotools

Hospital infections associated with multidrug-resistant (MDR) Pseudomonas aeruginosa are a worldwide public health problem. Efflux systems and biofilm formation are mechanisms related to resistance to carbapenemics. In this study, quantum dots (QDs) were used to evaluate the effect of carbonyl cyanide-3-chlorophenylhydrazone (CCCP), an efflux pump system inhibitor, on biofilm formation and antimicrobial resistance profile of P. aeruginosa strains. For this, QDs were covalently conjugated to meropenem (MPM) and incubated with a P. aeruginosa resistant isolate (P118) or a control sensitive strain (ATCC Pa27853). P118 was also analyzed with conjugates after previous CCCP efflux inhibitor incubation. Fluorescence microscopy images showed that both sensitive and resistant bacteria were efficiently labeled. Nevertheless, P118 isolates presented fluorescent cell agglomerates, suggesting biofilm formation. The addition of the CCCP changed the labeling profile of the resistant isolate, and the absence of agglomerates was observed, indicating no biofilm formation. Genetic assays revealed the presence of MexA and MexE genes encoding channel proteins from efflux pump systems in both resistant and sensitive strains. Disk-diffusion and broth microdilution tests determined drug susceptibility profiles in the presence and absence of CCCP for P118 isolates. We verified that the CCCP efflux system inhibitor may contribute to P. aeruginosa resistant phenotype reduction for some antimicrobials. This study verified the efficiency of QD-MPM conjugates to trigger and study biofilm formation, or its inhibition, before and after CCCP addition. QDs conjugated to antimicrobials can be used as nanotools to investigate multidrug-resistant bacterial strains on biofilm formation.

Bauhinia monandra leaf lectin (BmoLL) conjugated with quantum dots as fluorescent nanoprobes for biological studies: application to red blood cells

Carbohydrates perform important physiological functions in eukaryotic and prokaryotic cells. Indeed, alterations in glycan patterns may be associated with disorders. The analysis of these sugars can be reached using nanoprobes composed by lectins associated with fluorescent nanoparticles. This study reports the conjugation of a galactose-binding lectin (BmoLL) isolated from Bauhinia monandra leaves with quantum dots (QDs) by adsorption. QDs-BmoLL conjugates showed bright fluorescence and the hemagglutination assay revealed that the lectin preserved its carbohydrate-binding ability after the conjugation. To evaluate the efficiency/specificity of the bioconjugate, ABO human red blood cells (RBCs) were used as biological models and the labeling was analyzed by flow cytometry. Among ABO blood groups, higher labeling (71.7 ± 5.9%) was detected for B-type RBCs, whose antigens have galactose in their structure. The specificity of labeling was confirmed since A- and O-types RBCs incubated with QDs-BmoLL, as well as B-type cells incubated with previously galactose-inhibited conjugates, were labeled below 6%. In AB-type RBCs, which simultaneously have B and A (N-acetylgalactosamine) antigens on their membrane, the labeling was ca. 14.1 ± 4.8%. Therefore, a successful conjugation was reached and QDs-BmoLL conjugates can be considered promising fluorescent nanoprobes for biological investigations.

Biomechanical and biochemical investigation of erythrocytes in late stage human leptospirosis

Leptospirosis is a zoonotic disease caused by bacteria of the genus Leptospira, which can cause lipid changes in the erythrocyte membrane. Optical tweezers were used to characterize rheological changes in erythrocytes from patients with leptospirosis in the late stage. Biochemical methods were also used for quantification of plasma lipid, erythrocyte membrane lipid, and evaluation of liver function. Our data showed that the mean elastic constant of erythrocytes from patients with leptospirosis was around 67% higher than the control (healthy individuals), indicating that patient’s erythrocytes were less elastic. In individuals with leptospirosis, several alterations in relation to control were observed in the plasma lipids, however, in the erythrocyte membrane, only phosphatidylcholine showed a significant difference compared to control, increasing around 41%. With respect to the evaluation of liver function of individuals with leptospirosis, there was a significant increase in levels of alanine transaminase (154%) and aspartate transaminase (150%), whereas albumin was 43.8% lower than control (P<0.01). The lecithin-cholesterol acyltransferase fractional activity was 3.6 times lower in individuals with leptospirosis than in the healthy individuals (P<0.01). The decrease of the erythrocyte elasticity may be related to the changes of erythrocyte membrane phospholipids composition caused by disturbances that occur during human leptospirosis, with phosphatidylcholine being a strong candidate in the erythrocyte rheological changes.

Quantum dots functionalized with 3-mercaptophenylboronic acids as novel nanoplatforms to evaluate sialic acid content on cell membranes

Sialic acids (SAs) modulate essential physiological and pathological conditions, including cell-cell communication, immune response, neurological disorders, and cancer. Besides, SAs confer negative charges to cell membranes, also contributing to hemorheology. Phenylboronic acids, called as mimetic lectins, have been highlighted to study SA profiles. The association of these interesting molecules with the optical properties of quantum dots (QDs) can provide a deeper/complementary understanding of mechanisms involving SAs. Herein, we explored the thiol affinity to the QD surface to develop a simple, fast and direct attachment procedure to functionalize these nanocrystals with 3-mercaptophenylboronic acids (MPBAs). The functionalization was confirmed by fluorescence correlation spectroscopy and inductively coupled plasma spectrometry. The conjugate specificity/efficiency was proved in experiments using red blood cells (RBCs). A labeling >90% was found for RBCs incubated with conjugates, which reduced to 17% after neuraminidase pretreatment. Moreover, QDs-MPBA conjugates were applied in a comparative study using acute (KG-1) and chronic (K562) myelogenous leukemia cell lines. Results indicated that KG-1 membranes have a greater level of SA, with 100% of cells labeled and a median of fluorescence intensity of ca. 2.5-fold higher when compared to K562 (94%). Therefore, this novel QDs-MPBA conjugate can be considered a promising nanoplatform to evaluate SA contents in a variety of biological systems.

Evaluating internalization and recycling of folate receptors in breast cancer cells using quantum dots

Folic acid (FA) regulates metabolic activities essential to the human body. FA receptor (FR) overexpression has been reported for many cancers, but there are still few or conflicting data about FRs in breast cancer cells. Quantum dots (QDs) have arisen as tools to elucidate aspects on FRs, due to their unique physicochemical properties. Herein, QDs conjugated to FA were explored to study the internalization and recycling of FRs in breast cancer cells, using HeLa as an out-group control. QDs were covalently conjugated to FA under different conditions. The best conjugate was applied to study FRs in HeLa, MCF7, MDA-MB231, and T47D cells applying confocal microscopy and flow cytometry analyses. The conjugation efficiency and specificity were evaluated, respectively, using fluorescence correlation spectroscopy (FCS) and saturation assays. FCS confirmed the effectiveness of the conjugation. HeLa and T47D had/internalized a higher amount of FRs (95% and 90% of labeling, respectively) than MDA-MB231 cells (68%). MCF7 cells seem to have very low functional FRs (3%). Saturation assays proved the specificity of QD-FA conjugates and suggested that FR recycling rate is low in the majority of cells studied, except for T47D. QD-FA conjugates were successfully developed. Therapies targeting FRs may be more effective for HeLa, T47D, and MDA-MB231.

Anionic Quantum Dots reveal actin-microridges in zebrafish epidermis

Enhancement of hydrophilicity and functionalization of CdTe QDs (Quantum Dots) via surface modifications have made them suitable to be used as specific probes for cell imaging. Applications for targeting cell surfaces have been widely demonstrated in vitro but their use in animal models is not trivial. Here, we reported the interaction of mercaptosuccinic-coated (MSA) CdTe QDs with the epidermis of living and Carnoy-fixed zebrafish embryos. QDs concentrate along adherent junctions and reveal the characteristic pattern of actin microridges at the apical surface of the enveloping layer. In our study, labeling with anionic QDs is attained within few minutes at submicromolar concentrations in whole mounted Carnoy-fixed zebrafish embryos, providing a faster approach compared with immunodetection or standard Phalloidin staining of actin for visualization by fluorescence microscopy.

Resazurin-Based Assay to Evaluate Cell Viability After Quantum Dot Interaction

The increasing applications of quantum dots (QDs) as optic tools in life science have stimulated researchers to evaluate the effects of these nanoprobes in cell viability using a variety of methods, especially colorimetric ones. One of the most applied tests is the MTT assay. In comparison to MTT, for example, the resazurin-based method has the main advantage of not evaluating the cells directly, thus eliminating false-positive results that may arise from the overlap of the absorbances of the QD with the colorimetric compound. Therefore, herein, we describe the resazurin assay as an alternative, simple, quick, sensitivity, reproducible, and nontoxic test to evaluate the in vitro cell viability after QD exposure. Moreover, this test presents an additional advantage; the cells remain viable for complementary experimental procedures, such as cell migration or adhesion.

Studies on Toxicity of Suspensions of CdTe Quantum Dots to Biomphalaria glabrata Mollusks

Quantum dots have generated great interest because of their optical properties, both to life sciences and electronics applications. However, possible risks to the environment associated with these nanoparticles are still under investigation. The present study aimed to evaluate the toxicity of suspensions of cadmium telluride (CdTe) quantum dots to Biomphalaria glabrata mollusks, a very sensitive aquatic environmental bioindicator for physical and chemical agents. Toxicity was examined by using embryos and adult mollusks as well as hemocytes. The distribution of cadmium in the organs of adults was also assessed. Effects of the stabilizing agent of the quantum dots were also evaluated. Animals were exposed to suspensions of quantum dots for 24 h, at concentrations varying from 1.2 to 20 nM for embryos and from 50 to 400 nM for adult mollusks. Results showed that suspensions of quantum dots induced malformations and mortality in embryos and mortality in adults, depending on the concentration applied. In the cytotoxicity study, hemocyte apoptosis was observed in adults exposed to the highest concentration of quantum dots applied as well as to the stabilizing agent. Cell binucleation and micronucleus frequencies were not significative. Bioaccumulation evaluation revealed that quantum dots targeted the digestive gland (hepatopancreas). Taken together, outcomes suggested that specific nano-effects related directly not only to composition but also to the aggregation of quantum dots may be mediating the observed toxicity. Thus B. glabrata was determined to be a very sensitive species for interpreting possible nano-effects in aquatic environments. Environ Toxicol Chem 2019;38:2128-2136. © 2019 SETAC.

P1922Ablation index-guided ablation versus second-generation cryoballoon for first pulmonary vein isolation in atrial fibrillation

Background

In a recent trial, cryoballoon (CB) ablation was non-inferior to radiofrequency ablation regarding effectiveness in atrial fibrillation (AF). Ablation index (AI) provides a more accurate estimation of ablation quality using three variables: power delivered with time, contact force and catheter stability. The additional benefit of AI-guided ablation versus CB ablation is unknown.

Objective

To compare AI-guided ablation and CB ablation for first pulmonary vein isolation (PVI) in patients with AF.

Methods

We assessed 141 patients (62±12 years old, 76 men and 126 paroxysmal AF) with drug refractory symptomatic AF submitted to AI-guided PVI or second-generation CB catheter. Endpoint was AF/AT/AFL recurrence after a 3-month blanking period with a minimum follow-up of 6 months. Cox regression was used to assess the relationship between type of ablation and AF recurrence.

Results

Fifty-seven patients underwent AI-guided PVI and 84 patients underwent CB ablation. The baseline characteristics are described in table 1. Procedure duration was significantly higher in AI group (150 vs 111 min, P<0.001) although requiring significant less fluoroscopy time (5 min vs 20 min; P<0.001). There was a transient phrenic nerve palsy in CB group and a cardiac tamponade in AI group. During a mean follow-up of 10±3 months there were 23 recurrences (27%) in CB group vs 7 recurrences (12%) in AI group (log rank 0.042) (Fig B). When adjusted for CHA2DS2-VASc score, left atrium diameter (mm) and type of AF (Cox regression), there was lower arrhythmia recurrence in AI group (HR 0.42; 95% CI 0.18–0.99; p=0.047).

Table 1. Baseline characteristics

Conclusion

In this analysis, AI-guided ablation was associated with lower arrhythmia recurrence when compared with CB ablation. This hypothesis should be further evaluated in a prospective randomized trial.

Evaluating glucose and mannose profiles in Candida species using quantum dots conjugated with Cramoll lectin as fluorescent nanoprobes

Glycoconjugates found on cell walls of Candida species are fundamental for their pathogenicity. Laborious techniques have been employed to investigate the sugar composition of these microorganisms. Herein, we prepared a nanotool, based on the fluorescence of quantum dots (QDs) combined with the specificity of Cramoll lectin, to evaluate glucose/mannose profiles on three Candida species. The QDs-Cramoll conjugates presented specificity and bright fluorescence emission. The lectin preserved its biological activity after the conjugation process mediated by adsorption interactions. The labeling of Candida species was analyzed by fluorescence microscopy and quantified by flow cytometry. Morphological analyses of yeasts labeled with QDs-Cramoll conjugates indicated that C. glabrata (2.7 μm) was smaller when compared to C. albicans (4.0 μm) and C. parapsilosis sensu stricto (3.8 μm). Also, C. parapsilosis population was heterogeneous, presenting rod-shaped blastoconidia. More than 90% of cells of the three species were labeled by conjugates. Inhibition and saturation assays indicated that C. parapsilosis had a higher content of exposed glucose/mannose than the other two species. Therefore, QDs-Cramoll conjugates demonstrated to be effective fluorescent nanoprobes for evaluation of glucose/mannose constitution on the cell walls of fungal species frequently involved in candidiasis.

The effects of endoplasmic reticulum stressors, tunicamycin and dithiothreitol on Trypanosoma cruzi

In higher eukaryotic cells, pertubations in ER environment, called ER stress, usually activate unfolded protein response (UPR) pathway in an attempt to re-stablish the ER homeostasis and prevent cell death. Because trypanosomatids appear to lack the classical UPR, it is not clear how these parasites respond to ER stress. Thus, the aim of this work was to evaluate the effects of ER stressors tunicamycin (TM) or dithiothreitol (DTT) on Trypanosoma cruzi. The TM treatment showed strong trypanostatic effect. At 2.5 μg/mL of TM, the mRNA levels of both binding protein (BiP) and calreticulin (CRT) increased significantly, whereas the protein levels of BiP remained stable. TM treatment induced ultrastructural changes compatible with an autophagic process. The DTT treatment inhibited the cell growth, induced drastic morphological changes, mitochondrial membrane depolarization and increased ROS production. The expression of BiP apparently was not affected by DTT, whereas the mRNA levels of BiP and CRT were significantly reduced. Our results suggest that TM induces autophagy/ER-phagy without causing substantial injury to the parasite. Conversely, the DTT treatment seems to rupture the mitochondrion homeostasis leading to parasite death. The comprehension of the mechanisms behind the susceptibility of T. cruzi to ER stress open perspectives for the development of chemotherapeutic agents addressed to these pathways.

Evaluating the glycophenotype on breast cancer tissues with quantum dots-Cramoll lectin conjugates

During carcinogenesis, changes in the glycosylation can modulate many biological processes. Thus, the interest in exploring and understanding the roles of carbohydrates as cancer biomarkers has been increasing. Lectins have been applied as useful tools in glycobiology, especially when associated with fluorescent reporters. Therefore, to take advantage of the physicochemical properties of quantum dots (QDs), herein, we conjugated Cramoll, a lectin that recognizes glucose/mannose residues, with those nanoparticles. We applied the conjugates to investigate the glycocode of normal, fibroadenoma (FB), and invasive ductal carcinoma (IDC) human breast tissues. Additionally, we proposed a method to quantitatively evaluate the tissue labeling intensity by a fluorescence microplate assay (FMA). Conjugates showed intense fluorescence and specificity. The lectin activity and secondary structure were also preserved after the conjugation with QDs. Moreover, fluorescence images showed that ductal cells of normal and FB tissues were preferentially labeled by conjugates, whereas both cells and stroma were strongly labeled in IDC. FMA showed in a quantitative, practical, and sensitive way that the level of exposed glucose/mannose residues increased accordingly to the sample malignancy degree. In conclusion, QDs-Cramoll conjugates can be considered effective, specific, and versatile probes to evaluate glycan profiles in normal and transformed tissues, by fluorescence microscopy as well as FMA quantification. Furthermore, FMA showed to be a potential method that can be applied with other fluorescent conjugates.