Search

Stem-cell-derived extracellular vesicles (EVs) have demonstrated multiple beneficial effects in preclinical models of cardiac diseases. However, poor retention at the target site may limit their therapeutic efficacy. Cardiac extracellular matrix hydrogels (cECMH) seem promising as drug-delivery materials and could improve the retention of EVs, but may be limited by their long gelation time and soft mechanical properties. Our objective was to develop and characterize an optimized product combining cECMH, polyethylene glycol (PEG), and EVs (EVs–PEG–cECMH) in an attempt to overcome their individual limitations: long gelation time of the cECMH and poor retention of the EVs. The new combined product presented improved physicochemical properties (60% reduction in half gelation time, p &lt, 0.001, and threefold increase in storage modulus, p &lt, 0.01, vs. cECMH alone), while preserving injectability and biodegradability. It also maintained in vitro bioactivity of its individual components (55% reduction in cellular senescence vs. serum-free medium, p &lt, 0.001, similar to EVs and cECMH alone) and increased on-site retention in vivo (fourfold increase vs. EVs alone, p &lt, 0.05). In conclusion, the combination of EVs–PEG–cECMH is a potential multipronged product with improved gelation time and mechanical properties, increased on-site retention, and maintained bioactivity that, all together, may translate into boosted therapeutic efficacy.

Nonrevascularizable coronary artery disease is a frequent cause of hibernating myocardium leading to heart failure (HF). Currently, there is a paucity of therapeutic options for patients with this condition. There is a lack of animal models resembling clinical features of hibernating myocardium. Here we present a large animal model of hibernating myocardium characterized by serial multimodality imaging. Yucatan minipigs underwent a surgical casein ameroid implant around the proximal left anterior descending coronary artery (LAD), resulting in a progressive obstruction of the vessel. Pigs underwent serial multimodality imaging including invasive coronary angiography, cardiac magnetic resonance (CMR), and hybrid 18F-Fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET/CT). A total of 43 pigs were operated on and were followed for 120 ± 37 days with monthly multimodality imaging. 24 pigs (56%) died during the follow-up. Severe LAD luminal stenosis was documented in all survivors. In the group of 19 long-term survivors, 17 (90%) developed left ventricular systolic dysfunction [median LVEF of 35% (IQR 32.5-40.5%)]. In 17/17, at-risk territory was viable on CMR and 14 showed an increased glucose uptake in the at-risk myocardium on 18FDG-PET/CT. The present pig model resembles most of the human hibernated myocardium characteristics and associated heart failure (systolic dysfunction, viable myocardium, and metabolic switch to glucose). This human-like model might be used to test novel interventions for nonrevascularizable coronary artery disease and ischemia heart failure as a previous stage to clinical trials. his study has been partially funded by the Horizon 2020 European Research Area Network on Cardiovascular Diseases (ERA-CVD) Joint Transnational Call “AC16/00021: FAT-4HEART,” by the Spanish Society of Cardiology through a “Translational Research grant 2019,” and by the Instituto de Salud Carlos III (ISCIII) and the European Regional Development Fund (ERDF) through a FIS grant (Ref # PI16/02110). Imaging phenotyping was partially supported by the Comunidad de Madrid (S2017/BMD-3867 RENIM-CM) and cofunded with European structural and investment funds. The CNIC is supported by the ISCIII, the Ministerio de Ciencia e Innovación and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (SEV-2015-0505). Sí

The DNA repair enzyme poly(ADP-ribose) polymerase 1 (PARP-1) is overexpressed in glioblastoma, with overall low expression in healthy brain tissue. Paired with the availability of specific small molecule inhibitors, PARP-1 is a near-ideal target to develop novel radiotherapeutics to induce DNA damage and apoptosis in cancer cells, while sparing healthy brain tissue. Methods: We synthesized an 131I-labeled PARP-1 therapeutic and investigated its pharmacology in vitro and in vivo. A subcutaneous tumor model was used to quantify retention times and therapeutic efficacy. A potential clinical scenario, intratumoral convection-enhanced delivery, was mimicked using an orthotopic glioblastoma model combined with an implanted osmotic pump system to study local administration of 131I-PARPi (PARPi is PARP inhibitor). Results: 131I-PARPi is a 1(2H)-phthalazinone, similar in structure to the Food and Drug Administration–approved PARP inhibitor AZD-2281. In vitro studies have shown that 131I-PARPi and AZD-2281 share similar pharmacologic profiles. 131I-PARPi delivered 134.1 cGy/MBq intratumoral injected activity. Doses to nontarget tissues, including liver and kidney, were significantly lower. Radiation damage and cell death in treated tumors were shown by p53 activation in U87-MG cells transfected with a p53-bioluminescent reporter. Treated mice showed significantly longer survival than mice receiving vehicle (29 vs. 22 d, P < 0.005) in a subcutaneous model. Convection-enhanced delivery demonstrated efficient retention of 131I-PARPi in orthotopic brain tumors, while quickly clearing from healthy brain tissue. Conclusion: Our results demonstrate 131I-PARPi’s high potential as a therapeutic and highlight PARP’s relevance as a target for radionuclide therapy. Radiation plays an integral role in brain tumor therapy, and radiolabeled PARP therapeutics could ultimately lead to improvements in the standard of care.

Exosomes are cell-derived nanovesicles with a proven intercellular signaling role in inflammation processes and immune response. Due to their natural origin and liposome-like structure, these nanometer-scale vesicles have emerged as novel platforms for therapy and diagnosis. In this work, goat milk exosomes are isolated and fully characterized in terms of their physicochemical properties, proteomics, and biochemical profile in healthy mice, and used to detect inflammatory processes by optical imaging. For the in vitro and in vivo experiments, the exosomes are covalently labeled with the commercial fluorophores sulfo-Cyanine 5 and BODIPY-FL to create nanoprobes. In vitro studies using confocal imaging, flow cytometry, and colorimetric assays confirm the internalization of the nanoprobes as well their lack of cytotoxicity in macrophage populations RAW 264.7. Optical imaging in the mouse peritoneal region confirms the in vivo ability of one of the nanoprobes to localize inflammatory processes. In vivo imaging shows exosome uptake in the inflamed peritoneal region, and flow-cytometric analysis of peritonitis exudates confirms the uptake by macrophage and neutrophil populations. These results support the promising use of goat milk exosomes as natural probes in the detection of inflammatory processes. This study has been funded by Instituto de Salud Carlos III, through the project "PI20/01632", co-funded by European Regional Development Fund (ERDF), "A way to make Europe" and by Comunidad de Madrid, project "Y2018/NMT-4949 (NanoLiver-CM)" and "S2017/BMD-3867 (RENIM-CM)", co-funded by European Structural and Investment Fund. This work has been also supported by "Diagnosis and treatment follow-up of severe Staphylococcal Infections with Anti-Staphylococcal antibodies and Immune-PET - Grant Fundación BBVA a Equipos de Investigación Científica 2018". A. Santos-Coquillat is grateful for financial support to Consejería de Educación e Investigación, co-financed by European Social Fund (ESF) grant PEJD-2018-POST/BMD-9592. A. Santos Coquillat is also funded by Instituto de Salud Carlos III, co-funded by European Social Fund "Investing in your future" (grant CD19/00136). The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia e Innovación (MCIN) and the Pro CNIC Foundation. The CNIO Proteomics Unit is funded by the H2020 project EPIC-XS (ref. 823839). Biomedical Imaging has been conducted at the Advanced Imaging Unit of the CNIC (Centro Nacional de Investigaciones Cardiovasculares Carlos III), Madrid, Spain.

In cases where catheter-related candidemia (CRC) must be managed without catheter withdrawal, antifungal lock therapy using highly active anti-biofilm (HAAB) agents is combined with systemic treatment. However, the activity of HAAB agents has never been studied in in vivo models using bioluminescence. We assessed the efficacy of micafungin using a bioluminescent Candida albicans SKCA23-ACTgLuc strain in an animal model of CRC. We divided 33 female Wistar rats into five groups: sham (A), infected nontreated (B), treated with lock therapy (0.16 mg/ml) (C), systemically treated only (1 mg/kg) (D), and systemically treated+lock (E). Catheters were colonized 24 h before insertion into the femoral vein (day 0). Treatment started on day 1 and lasted 7 days, followed by 7 days of surveillance. Bioluminescence assays were carried out on days 1, 3, 5, and 14, together with daily monitoring of clinical variables. Postmortem microbiological cultures from the catheter and several tissue samples were also obtained. Overall, 28 rats (84.8%) completed the study. Group B animals showed significant weight loss at days 2, 4, and 5 compared with groups C and D (P < .05). In group B, no animals survived after day 7, 75% had CRC, and bioluminescence remained constant 5 days after catheter implantation. Positive catheter culture rates in groups C, D, and E were, respectively, 83.3%, 62.5%, and 25.0% (P = .15). Micafungin proved to be a HAAB agent when administered both systemically and in lock therapy in an animal model of CRC, although the bioluminescence signal persists after treatment. This persistence should be further analyzed.

The use of click chemistry reactions for the functionalization of nanoparticles is particularly useful to modify the surface in a well-defined manner and to enhance the targeting properties, thus facilitating clinical translation. Here it is demonstrated that olefin metathesis can be used for the chemoselective functionalization of iron oxide nanoparticles with three different examples. This approach enables, in one step, the synthesis and functionalization of different water-stable magnetite-based particles from oleic acid-coated counterparts. The surface of the nanoparticles was completely characterized showing how the metathesis approach introduces a large number of hydrophilic molecules on their coating layer. As an example of the possible applications of these new nanocomposites, a focus was taken on atherosclerosis plaques. It is also demonstrated how the in vitro properties of one of the probes, particularly its Ca(2+) -binding properties, mediate their final in vivo use; that is, the selective accumulation in atherosclerotic plaques. This opens promising new applications to detect possible microcalcifications associated with plaque vulnerability. The accumulation of the new imaging tracers is demonstrated by in vivo magnetic resonance imaging of carotids and aorta in the ApoE(-/-) mouse model and the results were confirmed by histology.

The combination of nanoparticles, gene therapy, and medical imaging has given rise to a new field known as gene theranostics, in which a nanobioconjugate is used to diagnose and treat the disease. The process generally involves binding between a vector carrying the genetic information and a nanoparticle, which provides the signal for imaging. The synthesis of this probe generates a synergic effect, enhancing the efficiency of gene transduction and imaging contrast. We discuss the latest approaches in the synthesis of nanoparticles for magnetic resonance imaging, gene therapy strategies, and their conjugation and in vivo application.

The current study presents [(18)F]PARPi as imaging agent for PARP1 expression.[(18)F]PARPi was generated by conjugating a 2H-phthalazin-1-one scaffold to 4-[(18)F]fluorobenzoic acid. Biochemical assays, optical in vivo competition, biodistribution analysis, positron emission tomography (PET)/X-ray computed tomography, and PET/magnetic resonance imaging studies were performed in subcutaneous and orthotopic mouse models of glioblastoma.[(18)F]PARPi shows suitable pharmacokinetic properties for brain tumor imaging (IC50 = 2.8 ± 1.1 nM; logPCHI = 2.15 ± 0.41; plasma-free fraction = 63.9 ± 12.6 %) and accumulates selectively in orthotopic brain tumor tissue. Tracer accumulation in subcutaneous brain tumors was 1.82 ± 0.21 %ID/g, whereas in healthy brain, the uptake was only 0.04 ± 0.01 %ID/g.[(18)F]PARPi is a selective PARP1 imaging agent that can be used to visualize glioblastoma in xenograft and orthotopic mouse models with high precision and good signal/noise ratios. It offers new opportunities to non-invasively image tumor growth and monitor interventions.

New intravital optical imaging technologies have revolutionized our understanding of mammalian biology and continue to evolve rapidly. However, there are only a limited number of imaging probes available to date. In this study, we investigated in mouse models of glioblastoma whether a fluorescent small molecule inhibitor of the DNA repair enzyme PARP1, PARPi-FL, can be used as an imaging agent to detect glioblastomas in vivo. We demonstrated that PARPi-FL has appropriate biophysical properties, low toxicity at concentrations used for imaging, high stability in vivo, and accumulates selectively in glioblastomas due to high PARP1 expression. Importantly, subcutaneous and orthotopic glioblastoma xenografts were imaged with high contrast clearly defining tumor tissue from normal surrounding tissue. This research represents a step toward exploring and developing PARPi-FL as an optical intraoperative imaging agent for PARP1 in the clinic.