A Light-Triggerable Nanoparticle Library for the Controlled Release of Non-Coding RNAs.

RNA-based therapies offer a wide range of therapeutic interventions including the treatment of skin diseases; however, the strategies to efficiently deliver these biomolecules are still limited due to obstacles related to the cellular uptake and cytoplasmic delivery. Herein, we report the synthesis of a triggerable polymeric nanoparticle (NP) library composed of 160 formulations, presenting physico-chemical diversity and differential responsiveness to light. Six formulations were more efficient (up to 500 %) than commercially available lipofectamine in gene-knockdown activity. These formulations showed differential internalization by skin cells and the endosomal escape was rapid (minutes range). The NPs were effective in the release of siRNA and miRNA. Acute skin wounds treated with the top hit NP complexed with miRNA-150-5p healed faster than wounds treated with scrambled miRNA. Light-activatable NPs offer a new strategy to topically deliver non-coding RNAs.

Umbilical-Cord-Derived Mesenchymal Stromal Cells Modulate 26 Out of 41 T Cell Subsets from Systemic Sclerosis Patients.

Systemic sclerosis (SSc) is an immune-mediated disease wherein T cells are particularly implicated, presenting a poor prognosis and limited therapeutic options. Thus, mesenchymal-stem/stromal-cell (MSC)-based therapies can be of great benefit to SSc patients given their immunomodulatory, anti-fibrotic, and pro-angiogenic potential, which is associated with low toxicity. In this study, peripheral blood mononuclear cells from healthy individuals (HC, n = 6) and SSc patients (n = 9) were co-cultured with MSCs in order to assess how MSCs affected the activation and polarization of 58 different T cell subsets, including Th1, Th17, and Treg. It was found that MSCs downregulated the activation of 26 out of the 41 T cell subsets identified within CD4+, CD8+, CD4+CD8+, CD4-CD8-, and γδ T cells in SSc patients (HC: 29/42) and affected the polarization of 13 out of 58 T cell subsets in SSc patients (HC: 22/64). Interestingly, SSc patients displayed some T cell subsets with an increased activation status and MSCs were able to downregulate all of them. This study provides a wide-ranging perspective of how MSCs affect T cells, including minor subsets. The ability to inhibit the activation and modulate the polarization of several T cell subsets, including those implicated in SSc's pathogenesis, further supports the potential of MSC-based therapies to regulate T cells in a disease whose onset/development may be due to immune system's malfunction.

A light-triggerable formulation to control the stability of pro-angiogenic transcription factor hypoxia inducible factor-1α (HIF-1α).

The control of vascular remodeling mediated by transcription factor HIF-1α is critical in the treatment of several diseases including cancer, retinopathies, chronic wounds, and ischemic heart disease, among others. Gene silencing using a small interfering RNA (siRNA) is a promising therapeutic strategy to regulate HIF-1α; however, the delivery systems developed so far have limited endothelial targeting and efficiency. Herein, we have synthesized a light-triggerable polymeric nanoparticle (NP) library composed of 110 formulations which showed variable morphology, charge and disassembly rates after UV exposure. More than 35% of the formulations of the library were more efficient in gene knockdown than the siRNA delivered by a commercial transfection agent (lipofectamine RNAiMAX). The most efficient siRNA delivery formulations were tested against different cell types to identify one with preferential targeting to endothelial cells. Using a two-step methodology, we have identified a formulation that shows exquisite targeting to endothelial cells and is able to deliver more efficiently the siRNA that modulates HIF-1α than commercial transfection agents. Overall, the strategy reported here increases the specificity for tissue regulation and the efficiency for the intracellular delivery of siRNAs.

The Kinetics of Small Extracellular Vesicle Delivery Impacts Skin Tissue Regeneration.

Small extracellular vesicles (SEVs) offer a promising strategy for tissue regeneration, yet their short lifetime at the injured tissue limits their efficacy. Here, we show that kinetics of SEV delivery impacts tissue regeneration at tissue, cellular, and molecular levels. We show that multiple carefully timed applications of SEVs had superior regeneration than a single dose of the same total concentration of SEVs. Importantly, diabetic and non-diabetic wounds treated with a single time point dose of an injectable light-triggerable hydrogel containing SEVs demonstrated a robust increase in closure kinetics relative to wounds treated with a single or multiple doses of SEVs or platelet-derived growth factor BB, an FDA-approved wound regenerative therapy. The pro-healing activity of released SEVs was mediated at the tissue/cell level by an increase in skin neovascularization and re-epithelization and at the molecular level by an alteration in the expression of 7 miRNAs at different times during wound healing. This includes an alteration of has-miR-150-5p, identified here to be important for skin regeneration.

Modulation of Angiogenic Activity by Light-Activatable miRNA-Loaded Nanocarriers.

The combinatorial delivery of miRNAs holds great promise to modulate cell activity in the context of angiogenesis. Yet, the delivery of multiple miRNAs with spatiotemporal control remains elusive. Here, we report a plasmonic nanocarrier to control the release of two microRNAs. The nanocarrier consists of gold nanorods modified with single-stranded DNA for hybridization with complementary DNA-conjugated microRNAs. DNA strands with distinct melting temperatures enable the independent release of each microRNA with a near-infrared laser using the same wavelength but different powers. Tests in human outgrowth endothelial cells (OECs) indicate that this system can be used to silence different targets sequentially and, by doing so, to modulate cell activity with spatiotemporal resolution. Finally, using an in vivo acute wound healing animal model, it is demonstrated that the order by which each miRNA was released in transplanted OECs significantly impacted the wound healing kinetics.

Pulmonary embolism associated with a large tricuspid-related mass.

The case of a 43-year-old man with diabetes and alcoholism admitted to the emergency room with shock, fever, pleuritic chest pain and systemic symptoms is presented. Laboratory tests revealed anemia, leukocytosis, thrombocytopenia, high sedimentation rate and D-dimers, hypoxemia and hypocapnea. He also had sinus tachycardia, rSR' in V1 and an opacity on the periphery of the right pulmonary field. Blood and urine cultures were negative, as were serological markers. The echocardiogram showed a large mass adhering to the tricuspid valve, suggestive of myxoma. The patient underwent surgery, and anatomopathological examination of the mass showed it to be a bacterial vegetation, with no agent isolated. It is pointed out that differential diagnosis is difficult between a myxoma with systemic symptomatology associated with a possible pulmonary embolism, and tricuspid endocarditis with negative blood culture associated with a septic pulmonary embolism, which turned out to be the diagnosis in this patient.

Influência sócio-econômica sobre as Parasitoses Intestinais / Intestinal parasitosis: socioeconomic influences

O presente trabalho tem o objetivo de apresentar os índices de parasitoses achados em uma amostra de crianças entre 1 e 7 anos de idade na cidade de Porto Alegre, RS, Brasil, expressando a influência da classe sócio-econômica sobre esses índices em nosso meio. Foram estudadas prospectivamente 166 crianças nos anos de 1993/1994 através de exames parasitológicos de fezes(92 provenientes da creche "A", frequentada por crianças de classe-média;74 da creche "B", frequentada por crianças de classe econômica baixa)...

Fasciolíase humana na Brasil diagnosticada por colangiografia endoscópica retrógrada / Human fascioliasis in BRasil diagnosed with endoscopic retrograde cholangiography

A fasciolíase humana é rara. O homem é um hospedeiro acidental da Fasciola hepatica. O parasita se instala nos canais bibliares e na vesícula bibliar simulando um cálculo biliar. Neste relato, descrevemos situaçäo em que a infestaçäo pela F. hepatica resultou em complicaçöes biliares, como icterícia e cólica biliar. O diagnóstico por imagem foi realizado por meio de colangiografia endoscópica retrógrada, que demonstrou a presença de estrutura no ducto bibliar extra-hepático. Foi efetuada esfincterotomia e remoçäo da mesma com cesta, havendo resoluçäo dos sintomas. O diagnóstico laboratorial demonstrou que o parasita era F. hepatica

Cryptococcus neoformans: epidemiologia, microbiologia, clínica e terapêutica / Cryptococcus neoformans: epidemiology, microbiology and therapeutics

O Cryptococcus neoformans é um fungo oportunista responsável por infecções em humanos. O trabalho revisa a literatura sobre os aspectos epidemiológico, microbiológico, clínico e terapêutico da criptococose em nosso meio