scholarly journals The Role of the Gut-Brain Axis in Neurodegenerative Diseases and Relevance of the Canine Model: A Review

Author(s):  
Yoko Ambrosini ◽  
Dana Borcherding ◽  
Anumantha Kanthasamy ◽  
Hyun Jung Kim ◽  
Albert Jergens ◽  
...  

Identifying appropriate animal models is critical in developing translatable in vitro and in vivo systems for therapeutic development and investigating disease pathophysiology. These animal models should have direct biological and translational relevance to the underlying disease they are supposed to mimic. Aging dogs naturally develop a cognitive decline in many aspects including learning and memory, but also exhibit human-like individual variability in the aging process. Neurodegenerative processes that can be observed in both human and canine brains include the progressive accumulation of β-amyloid (Aβ) found as diffuse plaques in the prefrontal cortex, including the gyrus proreus, the hippocampus, and in the cerebral vasculature. A growing body of epidemiological data shows that human patients with neurodegenerative diseases have concurrent intestinal lesions, and histopathological changes in the gastrointestinal (GI) tract occurs decades that evolve before neurodegenerative changes. Gut microbiome alterations also have been observed in many neurodegenerative diseases including Alzheimer’s and Parkinson’s diseases, and inflammatory CNS diseases. Interestingly, only recently has the dog gut microbiome been recognized to more closely resemble in composition and in functional overlap with the human gut microbiome as compared to rodent models. This article aims to review the physiology of the gut-brain axis (GBA), and its involvement with neurodegenerative diseases in dogs and humans. Additionally, we outline the advantages and disadvantages of traditional in vitro and in vivo models and discuss future research directions investigating major human neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases using dogs.

2019 ◽  
Vol 26 (19) ◽  
pp. 3439-3456 ◽  
Author(s):  
Laura Vergani

Background: Fatty liver, or steatosis, is a condition of excess accumulation of lipids, mainly under form of triglycerides (TG), in the liver, and it is the hallmark of non-alcoholic fatty liver disease (NAFLD). NAFLD is the most common liver disorder world-wide and it has frequently been associated with obesity, hyperlipidemia and insulin resistance. Free fatty acids (FA) are the major mediators of hepatic steatosis; patients with NAFLD have elevated levels of circulating FA that correlate with disease severity. Methods: Steatosis is a reversible condition that can be resolved with changed behaviors, or that can progress towards more severe liver damages such as steatohepatitis (NASH), fibrosis and cirrhosis. In NAFLD, FA of exogenous or endogenous origin accumulate in the hepatocytes and trigger liver damages. Excess TG are stored in cytosolic lipid droplets (LDs) that are dynamic organelles acting as hubs for lipid metabolism. Results: In the first part of this review, we briefly reassumed the main classes of FA and their chemical classification as a function of the presence and number of double bonds, their metabolic pathways and effects on human health. Then, we summarized the main genetic and diet-induced animal models of NAFLD, as well as the cellular models of NAFLD. Conclusions: In recent years, both the diet-induced animal models of NAFLD as well as the cellular models of NAFLD have found ever more application to investigate the mechanisms involved in NAFLD, and we referred to their advantages and disadvantages.


2020 ◽  
Vol 26 (35) ◽  
pp. 4362-4372
Author(s):  
John H. Miller ◽  
Viswanath Das

No effective therapeutics to treat neurodegenerative diseases exist, despite significant attempts to find drugs that can reduce or rescue the debilitating symptoms of tauopathies such as Alzheimer’s disease, Parkinson’s disease, frontotemporal dementia, amyotrophic lateral sclerosis, or Pick’s disease. A number of in vitro and in vivo models exist for studying neurodegenerative diseases, including cell models employing induced-pluripotent stem cells, cerebral organoids, and animal models of disease. Recent research has focused on microtubulestabilizing agents, either natural products or synthetic compounds that can prevent the axonal destruction caused by tau protein pathologies. Although promising results have come from animal model studies using brainpenetrant natural product microtubule-stabilizing agents, such as paclitaxel analogs that can access the brain, epothilones B and D, and other synthetic compounds such as davunetide or the triazolopyrimidines, early clinical trials in humans have been disappointing. This review aims to summarize the research that has been carried out in this area and discuss the potential for the future development of an effective microtubule stabilizing drug to treat neurodegenerative disease.


Author(s):  
Zachary Fralish ◽  
Ethan M. Lotz ◽  
Taylor Chavez ◽  
Alastair Khodabukus ◽  
Nenad Bursac

The neuromuscular junction (NMJ) is a specialized cholinergic synaptic interface between a motor neuron and a skeletal muscle fiber that translates presynaptic electrical impulses into motor function. NMJ formation and maintenance require tightly regulated signaling and cellular communication among motor neurons, myogenic cells, and Schwann cells. Neuromuscular diseases (NMDs) can result in loss of NMJ function and motor input leading to paralysis or even death. Although small animal models have been instrumental in advancing our understanding of the NMJ structure and function, the complexities of studying this multi-tissue system in vivo and poor clinical outcomes of candidate therapies developed in small animal models has driven the need for in vitro models of functional human NMJ to complement animal studies. In this review, we discuss prevailing models of NMDs and highlight the current progress and ongoing challenges in developing human iPSC-derived (hiPSC) 3D cell culture models of functional NMJs. We first review in vivo development of motor neurons, skeletal muscle, Schwann cells, and the NMJ alongside current methods for directing the differentiation of relevant cell types from hiPSCs. We further compare the efficacy of modeling NMDs in animals and human cell culture systems in the context of five NMDs: amyotrophic lateral sclerosis, myasthenia gravis, Duchenne muscular dystrophy, myotonic dystrophy, and Pompe disease. Finally, we discuss further work necessary for hiPSC-derived NMJ models to function as effective personalized NMD platforms.


2000 ◽  
Vol 11 (1) ◽  
pp. 51-59 ◽  
Author(s):  
Olaf Weber ◽  
Jürgen Reefschläger ◽  
Helga Rübsamen-Waigmann ◽  
Siegfried Raddatz ◽  
Matthias Hesseling ◽  
...  

Novel peptide aldehydes (PAs) were identified as potent inhibitors of human cytomegalovirus (HCMV) in vitro. Although these compounds were highly effective against HCMV, they did not exhibit any activity against murine cytomegalovirus (MCMV). The purpose of this study was to test the antiviral activity of PA 8 as a representative of this novel class of inhibitors against HCMV in vivo. Because of the strict species specificity of HCMV we had to use two artificial animal models. In the first model, HCMV-infected human cells were entrapped into agarose plugs and transplanted into mice. In the second model, SCID mice were transplanted with human tissues that were subsequently infected with a clinical isolate of HCMV. In these two models the antiviral activity of PA 8 was clearly demonstrated, ganciclovir only being slightly superior in its in vivo antiviral activity.


2020 ◽  
Vol 21 (14) ◽  
pp. 4993 ◽  
Author(s):  
Raphael Mohr ◽  
Burcin Özdirik ◽  
Jana Knorr ◽  
Alexander Wree ◽  
Münevver Demir ◽  
...  

Cholangiocarcinoma (CCA) comprises a heterogeneous group of primary liver tumors. They emerge from different hepatic (progenitor) cell populations, typically via sporadic mutations. Chronic biliary inflammation, as seen in primary sclerosing cholangitis (PSC), may trigger CCA development. Although several efforts were made in the last decade to better understand the complex processes of biliary carcinogenesis, it was only recently that new therapeutic advances have been achieved. Animal models are a crucial bridge between in vitro findings on molecular or genetic alterations, pathophysiological understanding, and new therapeutic strategies for the clinic. Nevertheless, it is inherently difficult to recapitulate simultaneously the stromal microenvironment (e.g., immune-competent cells, cholestasis, inflammation, PSC-like changes, fibrosis) and the tumor biology (e.g., mutational burden, local growth, and metastatic spread) in an animal model, so that it would reflect the full clinical reality of CCA. In this review, we highlight available data on animal models for CCA. We discuss if and how these models reflect human disease and whether they can serve as a tool for understanding the pathogenesis, or for predicting a treatment response in patients. In addition, open issues for future developments will be discussed.


2021 ◽  
Vol 91 (1) ◽  
pp. 86-98
Author(s):  
S. S. Malchenkova ◽  
◽  
N. S. Golyak ◽  
V. M. Tsarenkov ◽  
◽  
...  

The article presents the main types of laboratory animals that are used to study the transdermal permeability of chemical compounds. We described the structural features of epidermis, derma and skin appendages in humans and laboratory animals (small rodents, pigs, monkeys). We also emphasized advantages and disadvantages of various laboratory animals as objects for in vivo transdermal modeling. A method of extrapolation called “The parallelogram method” or «Triple Pack» has been singled out to predict the permeability of the human skin in the presence of experimental data on the permeability of the skin of animals in vivo and humans in vitro. The article describes the experimental design (including preparation of animals, premises and the substance applied) to determine transdermal permeability of substances in vivo under the guidelines of the World Health Organization and the Organization for Economic Cooperation and Development. Tissue microdialysis in volunteers has been identified as the most perfect and safest ways to promptly detect substances in the derma and tape stripping has been made in the cells of the stratum corneum.


2021 ◽  
Author(s):  
ling wang ◽  
yang yu ◽  
cong zhou ◽  
run wan ◽  
Yumin Li

Abstract Background and objectives: Cancer morbidity and mortality rates remain high, and thus, at present, considerable efforts are focused on finding drugs with higher sensitivity against tumor cells and fewer side effects. Several preclinical and clinical studies have examined the potential of repurposing disulfiram (DSF) as an anticancer treatment. This systematic review aimed to assess evidence regarding the antineoplastic activity of DSF in in vitro and in vivo models, as well as in humans.Methods: Two authors independently conducted this systematic review of English and Chinese articles from the PubMed, Embase, and the Cochrane Library databases up to July 2019. Eligible in vitro studies needed to include assessments of the apoptosis rate by flow cytometry using annexin V/propidium iodide, and studies in animal models and clinical trials needed to examine tumor inhibition rates, and progression-free survival (PFS) and overall survival (OS), respectively. Data were analyzed using descriptive statistics.Results: Overall, 35 studies, i.e., 21 performed in vitro, 11 based on animal models, and three clinical trials, were finally included. In vitro and animal studies indicated that DSF was associated with enhanced apoptosis and tumor inhibition rates. Human studies showed that DSF prolongs PFS and OS. The greatest anti-tumor activity was observed when DSF was used as combination therapy or as a nanoparticle-encapsulated molecule.Conclusions: This systematic review provides evidence regarding the anti-tumor activity of DSF in vitro, in animals, and in humans and indicates the optimal forms of treatment to be evaluated in future research.


Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 426 ◽  
Author(s):  
Sabari Nath Neerukonda ◽  
Upendra Katneni

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of CoV disease 2019 (COVID-19) is a highly pathogenic and transmissible CoV that is presently plaguing the global human population and economy. No proven effective antiviral therapy or vaccine currently exists, and supportive care remains to be the cornerstone treatment. Through previous lessons learned from SARS-CoV-1 and MERS-CoV studies, scientific groups worldwide have rapidly expanded the knowledge pertaining to SARS-CoV-2 virology that includes in vitro and in vivo models for testing of antiviral therapies and randomized clinical trials. In the present narrative, we review SARS-CoV-2 virology, clinical features, pathophysiology, and animal models with a specific focus on the antiviral and adjunctive therapies currently being tested or that require testing in animal models and randomized clinical trials.


Neurology ◽  
2018 ◽  
Vol 91 (2 Supplement 1) ◽  
pp. S14-S20 ◽  
Author(s):  
Jean-Philippe Brosseau ◽  
Dominique C. Pichard ◽  
Eric H. Legius ◽  
Pierre Wolkenstein ◽  
Robert M. Lavker ◽  
...  

ObjectiveA group of experts in dermatology, genetics, neuroscience, and regenerative medicine collaborated to summarize current knowledge on the defined factors contributing to cutaneous neurofibroma (cNF) development and to provide consensus recommendations for future research priorities to gain an improved understanding of the biology of cNF.MethodsThe group members reviewed published and unpublished data on cNF and related diseases via literature search, defined a set of key topic areas deemed critical in cNF pathogenesis, and developed recommendations in a series of consensus meetings.ResultsFive specific topic areas were identified as being relevant to providing an enhanced understanding of the biology of cNF: (1) defining the human cells of origin; (2) understanding the role of the microenvironment, focusing on neurons, mast cells, and fibroblasts; (3) defining the genetic and molecular differences between the cNFs, focusing on size and number; (4) understanding if sex hormones are critical for cNF development or progression; and (5) identifying challenges in establishing in vitro and in vivo models representing human cNF.ConclusionsThe complexity of cNF biology stems from its heterogeneity at multiple levels including genetic, spatial involvement, temporal development, and cellular composition. We propose a unified working model for cNF that builds a framework to address the key questions about cNF that, when answered, will provide the necessary understanding of cNF biology to allow meaningful development of therapies.


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