Neuropathology, diagnosis, and potential treatment of feline cognitive dysfunction syndrome and its similarities to Alzheimer's disease

Cognitive dysfunction syndrome (CDS) is a common age-related condition in domestic cats that is characterised by behavioural changes that ultimately lead to cognitive decline and dementia. The most common behavioural changes displayed by cats affected by CDS have been summarised under the acronym VISHDAAL and include excessive Vocalisation, especially at night, alterations in their Interaction with their owners (e.g., increased affection), alterations in their Sleep-wake cycles, House-soiling, spatial and/or temporal Disorientation, alterations in Activity levels, Anxiety, and/or Learning/memory deficits. Cats with CDS develop neuropathologies that share many similitudes to those seen in the brains of humans with Alzheimer’s disease (AD), which are the abnormal accumulation of amyloid-ß (Aß) forming senile plaques, and the presence of neurofibrillary tangles (NFT) formed by hyperphosphorylated tau deposits. In the present study, immunohistochemistry of seven different brain regions of cats of various ages, with and without CDS, revealed that cats accumulate intra and extracellular Aß deposits, plus intranuclear and intracytoplasmic hyperphosphorylated tau deposits. The intracytoplasmic deposits of Aß were mainly found in younger cats, whereas elderly cats accumulated large diffuse extracellular Aß deposits. While Aß senile plaques in people with AD have a dense core, the diffuse Aß deposits in cats are believed to be an early stage of senile plaques. In this study, intranuclear labelling for hyperphosphorylated tau was mainly found in the younger cats. In contrast, intranuclear labelling was rarely found in elderly cats, especially if pre-tangles were present. Furthermore, intracytoplasmic immunolabelling for hyperphosphorylated tau was mainly found in the brains of elderly cats. Due to its ultrastructural features, these deposits are considered to be pre-tangles, which are an early stage of the characteristic NFT seen in the human AD brain. Diagnosing CDS can be challenging, especially as the diagnosis can only be achieved by ruling out all other potential causes for the behavioural changes displayed by the cats. Veterinarians can only diagnose CDS after performing thorough examinations of the cats, which can be a slow, time-consuming, and expensive task. Hence, diagnostic tools and/or methods that may facilitate prompt diagnosis are urgently needed. Imaging techniques, such as magnetic resonance imaging (MRI), have recently emerged as potential diagnostic tools for assessing brain changes associated with ageing and AD in humans. These imaging techniques also have the potential to be effective in vivo diagnostic tools for assessing age-related brain changes and CDS in cats. In this study, age-related changes were assessed in different brain regions of cats of various ages, with and without CDS, by using MRI. Elderly cats in this study were shown to develop atrophy of the whole brain, the hippocampus, and the occipital lobe, plus enlargement of the ventricles. Most of these changes have also been described in elderly humans, especially in those with AD. While there is currently no treatment available for CDS in cats, interventions that can be considered for its management include environmental enrichment, dietary supplementations, specific diets, and potentially, medication (licensed for the treatment of dogs with CDS). Telmisartan is an angiotensin receptor blocker and an activator of PPARγ that has shown to reduce neuroinflammation, provide neuroprotection, and to restore cognition in humans and rodents. In this study, a three-month double-blinded placebo-controlled trial was performed in cats with severe CDS. Even though no statistically significant differences were found between the treatment groups, further studies are needed to determine the true potential of telmisartan for the treatment of CDS in cats. The present work furthers our understanding about the neuropathology of ageing and CDS in cats. Furthermore, it proposes the use of imaging techniques, especially of MRI, as a potential in vivo diagnostic tool for age-related changes that may lead to cognitive decline. Finally, it proposes the use of telmisartan as a potential treatment to reduce the clinical signs of CDS in cats

A fast, reliable and cost-effective method to generate tumor organs for therapy screening in vivo

Innovative anticancer treatments continuously require tissue bioengineering models to test novel therapies. The increasing number of developments based on nanotechnology for cancer therapy or theragnostics demand simple, reliable, fast and cost-effective cancer in vivo models for preclinical testing. However, despite the many tumor models available, very few reproduce the complex intratumoral cell-to-cell interactions as well as the accompanying systemic whole body effects resulting of the tumor organ metabolic, hormonal or growth factor activities, all having critical implications in the success of cancer therapies. Here we describe a reliable tumor model that can be easily reproduced to generate visible solid malignant melanoma tumor organs within a defined period of 5–10 days recapitulating the tumor stroma that is essential for cancer development. These models can be easily evaluated in vivo or by anatomo-pathological procedures. This method provides a fast, reproducible, reliable and cost-effective way to generate solid tumors for in vivo therapy, drug, nanomaterial or imaging probe evaluation, diagnostic or theragnostic screening and validation

Targeting Nanomaterials to Head and Neck Cancer Cells Using a Fragment of the Shiga Toxin as a Potent Natural Ligand

Head and Neck Cancer (HNC) is the seventh most common cancer worldwide with a 5-year survival from diagnosis of 50%. Currently, HNC is diagnosed by a physical examination followed by an histological biopsy, with surgery being the primary treatment. Here, we propose the use of targeted nanotechnology in support of existing diagnostic and therapeutic tools to prevent recurrences of tumors with poorly defined or surgically inaccessible margins. We have designed an innocuous ligand-protein, based on the receptor-binding domain of the Shiga toxin (ShTxB), that specifically drives nanoparticles to HNC cells bearing the globotriaosylceramide receptor on their surfaces. Microscopy images show how, upon binding to the receptor, the ShTxB-coated nanoparticles cause the clustering of the globotriaosylceramide receptors, the protrusion of filopodia, and rippling of the membrane, ultimately allowing the penetration of the ShTxB nanoparticles directly into the cell cytoplasm, thus triggering a biomimetic cellular response indistinguishable from that triggered by the full-length Shiga toxin. This functionalization strategy is a clear example of how some toxin fragments can be used as natural biosensors for the detection of some localized cancers and to target nanomedicines to HNC lesions.Funding: This research was funded by ISCIII Projects ref. PI19/00349, DTS19/00033, co-funded by ERDF/ESF, “Investing in your future”; and MICINN Projects ref. CTM2017-84050-R, NanoBioApp, and HIPERNANO Research Networks (MINECO-17-MAT2016-81955-REDT and RED2018-102626-T), MCIU/AEI/FEDER, EU under project PGC2018-101464-B-100, COST action Nano2Clinic CA17140, and IDIVAL for the INNVAL19/12 and INNVAL20/13 projects and PREVAL18/02, PREVAL16/02 and 16/03. M.B.L. acknowledges NORTE 2020 (2014-2020 North Portugal Regional Operational Program), and the ERDF (European Regional Development Fund) Grant NORTE-01-0145-FEDER- 000019, and 2014-2020 INTERREG Cooperation Programme Spain–Portugal (POCTEP) through the project 0624-2IQBIONEURO-6-E

Multiwalled Carbon Nanotubes inhibit tumor progression in a mouse model

Understanding the molecular mechanisms underlying the biosynthetic interactions between particular nanomaterials with specific cells or proteins opens new alternatives in nanomedicine and nanotoxicology. Multiwalled carbon nanotubes (MWCNTs) have long been explored as drug delivery systems and nanomedicines against cancer. There are high expectations for their use in therapy and diagnosis. These filaments can translocate inside cultured cells and intermingle with the protein nanofilaments of the cytoskeleton, interfering with the biomechanics of cell division mimicking the effect of traditional microtubule-binding anti-cancer drugs such as paclitaxel. Here, it is shown how MWCNTs can trigger significant anti-tumoral effects in vivo, in solid malignant melanomas produced by allograft transplantation. Interestingly, the MWCNT anti-tumoral effects are maintained even in solid melanomas generated from paclitaxel-resistant cells. These findings provide great expectation in the development of groundbreaking adjuvant synthetic microtubule-stabilizing chemotherapies to overcome drug resistance in cancer.Acknowledgements: We thank Dr. E. Flahaut for providing the MWCNTs. We are grateful to the Nikon A1R Laser Microscopy Unit of the IDIVAL Institute for the electron microscopy and confocal/time-lapse microscopy, and to M. Aramburu and J. Díaz-Gómez for their help. This work has been supported by the Spanish MINECO and European Union FEDER under Projects ref. PI13/01074 (AES 2013) and MAT2012-38664-C02-01. We especially thank the Fundación Eugenio Rodríguez Pascual (ref “Ayudas de investigación” 2014)

Carbon nanotubes gathered onto silica particles lose their biomimetic properties with the cytoskeleton becoming biocompatible

Carbon nanotubes (CNTs) are likely to transform the therapeutic and diagnostic fields in biomedicine during the coming years. However, the fragmented vision of their side effects and toxicity in humans has proscribed their use as nanomedicines. Most studies agree that biocompatibility depends on the state of aggregation/dispersion of CNTs under physiological conditions, but conclusions are confusing so far. This study designs an experimental setup to investigate the cytotoxic effect of individualized multiwalled CNTs compared to that of identical nanotubes assembled on submicrometric structures. Our results demonstrate how CNT cytotoxicity is directly dependent on the nanotube dispersion at a given dosage. When CNTs are gathered onto silica templates, they do not interfere with cell proliferation or survival becoming highly compatible. These results support the hypothesis that CNT cytotoxicity is due to the biomimetics of these nanomaterials with the intracellular nanofilaments. These findings provide major clues for the development of innocuous CNT-containing nanodevices and nanomedicines.Acknowledgments: This work was supported by the Spanish MINECO Project (references PI13/01074, PI16/00496 and CTM2014–58481-R, IDIVAL INNVAL15/15), Xunta de Galicia (Centro Singular de Investigación de Galicia-Accreditation 2016–2019 and EM2014/035), European Regional Development Fund – ERDF and Fundación Tatiana Pérez de Guzmán El Bueno

Biodegradable multi-walled carbon nanotubes trigger anti-tumoral effects

Carbon nanotubes are of huge biotechnological interest because they can penetrate most biological barriers and, inside cells, can biomimetically interact with the cytoskeletal filaments, triggering anti-proliferative and cytotoxic effects in highly dividing cells. Unfortunately, their intrinsic properties and bio-persistence represent a putative hazard that relapses their application as therapies against cancer. Here we investigate mild oxidation treatments to improve the intracellular enzymatic digestion of MWCNTs, but preserving their morphology, responsible for their intrinsic cytotoxic properties. Cell imaging techniques and confocal Raman spectroscopic signature analysis revealed that cultured macrophages can degrade bundles of oxidized MWCNTs (o-MWCNTs) in a few days. The isolation of nanotubes from these phagocytes 96 hours after exposure confirmed a significant reduction of approximately 30% in the total length of these filaments compared to the control o-MWCNTs extracted from the cell culture medium, or the intracellular pristine MWCNTs. More interestingly, in vivo single intratumoral injections of o-MWCNTs triggered ca. 30% solid melanoma tumour growth-inhibitory effects while displaying significant signs of biodegradation at the tumoral/peri-tumoral tissues a week after the therapy has had the effect. These results support the potential use of o-MWCNTs as antitumoral agents and reveal interesting clues of how to enhance the efficient clearance of in vivo carbon nanotubes.This work has been supported by the Spanish MINECO and European Union FEDER under Projects ref. PI13/01074, PI16/000496, MAT2015-69508-P, the NanoBioApp Network Ref. MINECO-17-MAT2016-81955-REDT, IDIVAL Projects ref. INNVAL15/16, INNVAL 17/11, PREVAL 16/03, and the Raman4clinics BMBS COST Action BM1401