Cellular interplay to 3D in vitro microphysiological disease model:cell patterning microbiota-gut-brain axis

The microbiota-gut-brain axis(MGBA)has emerged as a key prospect in the bidirectional communication between two major organ systems:the brain and the gut.Homeostasis between the two organ systems allows the body to function without disease,whereas dysbiosis has long-standing evidence of etiopathological conditions.The most common communication paths are the microbial release of metabolites,soluble neurotransmitters,and immune cells.However,each pathway is intertwined with a complex one.With the emergence of in vitro models and the popularity of three-dimensional(3D)cultures and Transwells,engineering has become easier for the scientific understanding of neurodegenerative diseases.This paper briefly retraces the possible communication pathways between the gut microbiome and the brain.It further elaborates on three major diseases:autism spectrum disorder,Parkinson’s disease,and Alzheimer’s disease,which are prevalent in children and the elderly.These diseases also decrease patients’quality of life.Hence,understanding them more deeply with respect to current advances in in vitro modeling is crucial for understanding the diseases.Remodeling of MGBA in the laboratory uses many molecular technologies and biomaterial advances.Spheroids and organoids provide a more realistic picture of the cell and tissue structure than monolayers.Combining them with the Transwell system offers the advantage of compartmentalizing the two systems(apical and basal)while allowing physical and chemical cues between them.Cutting-edge technologies,such as bioprinting and microfluidic chips,might be the future of in vitro modeling,as they provide dynamicity.

Organoids: a novel modality in disease modeling

Limitations of monolayer culture conditions have motivated scientists to explore new models that can recapitulate the architecture and function of human organs more accurately.Recent advances in the improvement of protocols have resulted in establishing three-dimensional(3D)organ-like architectures called‘organoids’that can display the characteristics of their corresponding real organs,including morphological features,functional activities,and personalized responses to specific pathogens.We discuss different organoid-based 3D models herein,which are classified based on their original germinal layer.Studies of organoids simulating the complexity of real tissues could provide novel platforms and opportunities for generating practical knowledge along with preclinical studies,including drug screening,toxicology,and molecular pathophysiology of diseases.This paper also outlines the key challenges,advantages,and prospects of current organoid systems.

Humanization for neurological disease modeling:A roadmap to increase the potential of Drosophila model systems

Neuroscience and neurology research is dominated by experimentation with rodents.Around 75%of neurology disease-associated genes have orthologs in Drosophila mel-anogaster,the fruit fly amenable to complex neurological and behavioral investiga-tions.However,non-vertebrate models including Drosophila have so far been unable to significantly replace mice and rats in this field of studies.One reason for this situ-ation is the predominance of gene overexpression(and gene loss-of-function)meth-odologies used when establishing a Drosophila model of a given neurological disease,a strategy that does not recapitulate accurately enough the genetic disease condi-tions.I argue here the need for a systematic humanization approach,whereby the Drosophila orthologs of human disease genes are replaced with the human sequences.This approach will identify the list of diseases and the underlying genes that can be adequately modeled in the fruit fly.I discuss the neurological disease genes to which this systematic humanization approach should be applied and provide an example of such an application,and consider its importance for subsequent disease modeling and drug discovery in Drosophila.I argue that this paradigm will not only advance our un-derstanding of the molecular etiology of a number of neurological disorders,but will also gradually enable researchers to reduce experimentation using rodent models of multiple neurological diseases and eventually replace these models.

Genome engineering and disease modeling via programmable nucleases for insulin gene therapy;promises of CRISPR/Cas9 technology

Targeted genome editing is a continually evolving technology employing programmable nucleases to specifically change,insert,or remove a genomic sequence of interest.These advanced molecular tools include meganucleases,zinc finger nucleases,transcription activator-like effector nucleases and RNA-guided engineered nucleases(RGENs),which create double-strand breaks at specific target sites in the genome,and repair DNA either by homologous recombination in the presence of donor DNA or via the error-prone non-homologous end-joining mechanism.A recently discovered group of RGENs known as CRISPR/Cas9 gene-editing systems allowed precise genome manipulation revealing a causal association between disease genotype and phenotype,without the need for the reengineering of the specific enzyme when targeting different sequences.CRISPR/Cas9 has been successfully employed as an ex vivo gene-editing tool in embryonic stem cells and patient-derived stem cells to understand pancreatic beta-cell development and function.RNA-guided nucleases also open the way for the generation of novel animal models for diabetes and allow testing the efficiency of various therapeutic approaches in diabetes,as summarized and exemplified in this manuscript.

The generation and properties of human cortical organoids as a disease model for malformations of cortical development

As three-dimensional“organ-like”aggregates,human cortical organoids have emerged as powerful models for studying human brain evolution and brain disorders with unique advantages of humanspecificity,fidelity and manipulation.Human cortical organoids derived from human pluripotent stem cells can elaborately replicate many of the key properties of human cortical development at the molecular,cellular,structural,and functional levels,including the anatomy,functional neural network,and interaction among different brain regions,thus facilitating the discovery of brain development and evolution.In addition to studying the neuro-electrophysiological features of brain cortex development,human cortical organoids have been widely used to mimic the pathophysiological features of cortical-related disease,especially in mimicking malformations of cortical development,thus revealing pathological mechanism and identifying effective drugs.In this review,we provide an overview of the generation of human cortical organoids and the properties of recapitulated cortical development and further outline their applications in modeling malformations of cortical development including pathological phenotype,underlying mechanisms and rescue strategies.

Antibacterial Properties of Nano Silver-containing Orthodontic Cements in the Rat Caries Disease Model

The purpose of this study was to evaluate the antibacterial properties of experimental nano silver-containing cements（NSCs） using rat caries disease model. Nano silver base inorganic antibacterial powder was added to the reinforced glass ionomer cement at three different weight ratios to obtain a series of nano silver-containing cements, then two orthodontic cement products and three NSC samples were implanted into rat caries disease model, and their antibacterial properties were evaluated by the scanning electron microscope（SEM）. Moreover, the rat caries disease model were established by inoculating cariogenic bacteria S mutans into antibiotics treated rat mouths and feeding with cariogenic diet. The tested materials were bonded on the surface of the buccal half crowns of the upper fi rst premolar, and then fi xed under the rats＇ front teeth lingual side to acquire enough retention. The SEM results indicated that the growth of streptococcus mutans was very active in group of Transbond XT. One month later, S mutans scattered on the GC Fuji ORTHO LC surface, and then the number signifi cantly increased and arranged in chains after three months. In groups of NSC2, NSC3 and NSC4, the number of S mutans presented the downward trend and tended to disperse individually with the increase of silver nanoparticle content. We may conclude that the incorporation of silver nanoparticle enhanced GC Fuji ORTHO LC the adhesion restrain and killing effect to S mutans.

Persistence and Extinction of a Non-Autonomous Plant Disease Model with Roguing^*

On the basis of analyzing the shortages of present studies on plant disease model for autonomous phenomenon, and considering the actual situation, this paper applies the joint factors of environmental change and the infectivity for latent plants into the system;therefore we deal with a non-autonomous plant disease model with roguing. Some sufficient conditions are established for extinction of diseases and permanence of the system in this paper.

Neuroactive alkaloids that modulate the neuronal nicotinic receptor and provide neuroprotection in an Alzheimer's disease model:the case of Teline monspessulana

Despite the advances in combinatorial or synthetic chemis- try and bioinformatics, recent literature has demonstrated the relevance of nature and biomass as a source of new molecules to treat different pathologies, i.e., bioactive com- pounds obtained from Ecteinascidia turbinate to treat some types of cancer or rapamycin from Streptomyces hygroscop- icus to prevent organ rejection after transplant. This trend will continue simply due to the fact that Mother Nature has been synthesizing molecules for millions of years. In our lab- oratory, we have characterized several compounds obtained from natural sources and that possess important neuronal effects,

Zebrafish as a disease model for studying human hepatocellular carcinoma

Liver cancer is one of the world's most common cancers and the second leading cause of cancer deaths. Hepatocellular carcinoma(HCC), a primary hepatic cancer, accounts for 90%-95% of liver cancer cases. The pathogenesis of HCC consists of a stepwise process of liver damage that extends over decades, due to hepatitis, fatty liver, fibrosis, and cirrhosis before developing fully into HCC. Multiple risk factors are highly correlated with HCC, including infection with the hepatitis B or C viruses, alcohol abuse, aflatoxin exposure, and metabolic diseases. Over the last decade, genetic alterations, which include the regulation of multiple oncogenes or tumor suppressor genes and the activation of tumorigenesis-related pathways, have also been identified as important factors in HCC. Recently, zebrafish have become an important living vertebrate model organism, especially for translational medical research. In studies focusing on the biology of cancer, carcinogen induced tumors in zebrafish were found to have many similarities to human tumors. Several zebrafish models have therefore been developed to provide insight into the pathogenesis of liver cancer and the related drug discovery and toxicology, and to enable the evaluation of novel smallmolecule inhibitors. This review will focus on illustrativeexamples involving the application of zebrafish models to the study of human liver disease and HCC, through transgenesis, genome editing technology, xenografts,drug discovery, and drug-induced toxic liver injury.

Potential neuroprotection by Dendrobium nobile Lindl alkaloid in Alzheimer's disease models

At present,treatments for Alzheimer's disease can temporarily relieve symptoms but cannot prevent the decline of cognitive ability and other neurodegenerative changes.Dendrobium nobile Lindl alkaloid is the main active component of Dendrobium nobile Lindl.Dendrobium nobile Lindl alkaloid has been shown to resist aging,prolong life span,and exhibit immunomodulatory effects in animals.This review summarizes the mechanisms behind the neuroprotective effects reported in Alzheimer's disease animal models.The neuroprotective effects of Dendrobium nobile Lindl alkaloid have not been studied in patients.The mechanisms by which Dendrobium nobile Lindl alkaloid has been reported to improve cognitive dysfunction in Alzheimer's disease animal models may be associated with extracellular amyloid plaque production,regulation of tau protein hyperphosphorylation,inhibition of neuroinflammation and neuronal apoptosis,activation of autophagy,and enhanced synaptic connections.

Effect of Dachaihu decoction on non-alcoholic fatty liver disease model rats induced by a high-fat high-sugar diet

Objective:To establish an animal model consistent with the occurrence and development of non-alcoholic fatty liver disease(NAFLD)with which to assess the effects of a classical traditional Chinese medicine formula known as Dachaihu Decoction(DD)on NAFLD.Methods:Sixty rats were randomized into four groups:control,model,pioglitazone hydrochloride(PH)and DD in equal.NAFLD was produced via administration of a high-fat high-sugar diet for 16 weeks in all but the control group.From the 13th week,a solution of PH or DD prepared with water was delivered via intragastric administration to the PH and DD groups;the remaining two groups received an equivalent volume of distilled water.Twelve hours from the last administration,we selected eight rats from each group in random.After anesthetization,the abdominal aorta blood and liver tissues were collected.The morphological changes were observed and the levels of alanine aminotransferase(ALT),aspartate aminotransferase(AST),total cholesterol(TC),triglyceride(TG),low-density lipoprotein cholesterol(LDL-C),highdensity lipoprotein cholesterol(HDL-C),fasting plasma glucose(FBG),transforming growth factor-β1(TGF-β1),tumor necrosis factor-α(TNF-α),toll-like receptor-4(TLR4),and nuclear factor-kappa B(NF-κB)were tested.Results:Compared with the control group,the levels of serum ALT,AST,TC,TG,LDL-C and FBG,and TGF-β1,TNF-α,TLR4,NF-κB in the model group all showed significant increases(P<.01).Compared with the model group,these same indicators in the PH and DD groups all showed remarkable decreases(P<.05).Conclusion:The efficacy of DD in NAFLD rats was shown to be effectively equivalent to that of PH,with demonstrated effects of DD that included reductions in hepatic steatosis and serum and hepatic lipid levels,and lowered blood glucose levels.We deduce that DD has an inhibitory effect on NAFLD induced by a high-fat high-sugar diet in rats.

“Blind men and an elephant”:The need for animals in research,drug safety studies,and understanding civilizational diseases

Animal-based research and drug safety studies are essential to understanding the mysteries of nature and the long-term survival of humans.Due to the rapid increase in the global human population,conflict-and economically driven human migration,tourism-related activities,densely populated metropolitan areas,and local policies,humans will be affected by a multitude of novel disease-causing microorganisms and civilizational diseases.Despite disparities among countries,recent and planned changes in regulations concerning animal research and drug safety studies could have detrimental effects on both the animal research community and nations lacking sufficient social support systems.Based on existing scientific literature,I argue that we need animal research encompassing aspects such as animal development,behavior,drug safety studies,and for the understanding of future civilizational diseases.Depending on the nature of the research questions and local challenges,a suitable animal model organism should be made mandatory.

Global Dynamic Analysis of a Vector-Borne Plant Disease Model with Discontinuous Treatment

This paper proposes a vector-borne plant disease model with discontinuous treatment strategies. Constructing Lyapunov function and applying non-smooth theory to analyze discontinuous differential equations, the basic reproductive number R0 is proved, which determines whether the plant disease will be extinct or not. If R0 R0 > 1 , there exists a unique endemic equilibrium which is globally stable. The numerical simulations are provided to verify our theoretical results, which indicate that after infective individuals reach some level, strengthening treatment measures is proved to be beneficial in controlling disease transmission.

Dynamics of a Nonautonomous Plant Disease Model with General Nonlinear Incidence Rate and Time-Varying Impulse

In this paper, for controlling the spread of plant diseases, a nonautonomous SEIS (Susceptible → Exposed → Infectious → Susceptible) epidemic model with a general nonlinear incidence rate and time-varying impulsive control strategy is proposed and investigated. This novel model could result in an objective criterion on how to control plant disease transmission by replanting of healthy plants and removal of infected plants. Using the method of small amplitude perturbation, the sufficient conditions under which guarantee the globally attractive of the disease-free periodic solution and the permanence of the disease are obtained, that is, the disease dies out if R12>1.

LDN-73794 Attenuated LRRK2-Induced Degeneration in a <i>Drosophila</i>Parkinson’s Disease Model

Parkinson’s disease (PD) is a common neurodegenerative disease with unclear pathogenesis. Currently, there are no disease-modifying neuron-protecting drugs to slow down the neuronal degeneration. Mutations in the leucine-rich repeat kinase 2 (LRRK2) cause genetic forms of PD and contribute to sporadic PD as well. Disruption of LRRK2 kinase functions has become one of the potential mechanisms underlying disease-linked mutation-induced neuronal degeneration. To further characterize the pharmacological effects of a reported LRRK2 kinase inhibitor, LDN-73794, in vitro cell models and a LRRK2 Drosophila PD model were used. LDN-73794 reduced LRRK2 kinase activity in vitro and in vivo. Moreover, LDN-73794 increased survival, improved locomotor activity, and suppressed DA neuron loss in LRRK2 transgenic flies. These results suggest that inhibition of LRRK2 kinase activity can be a potential therapeutic strategy for PD intervention and LDN-73794 could be a potential lead compound for developing neuroprotective therapeutics.

Meaningful Contact Estimates among Children in a Childcare Centre with Applications to Contact Matrices in Infectious Disease Modelling

We present a mathematical model of a day care center in a developed country (such as Canada), in order to use it for the estimation of individual-to-individual contact rates in young age groups and in an educational group setting. In our model, individuals in the population are children (ages 1.5 to 4 years) and staff, and their interactions are modelled explicitly: person-to-person and person-to-environment, with a very high time resolution. Their movement and meaningful contact patterns are simulated and then calibrated with collected data from a child care facility as a case study. We present these calibration results as a first part in the further development of our model for testing and estimating the spread of infectious diseases within child care centers.

Physiology and health assessment,risk balance,and model for endstage liver disease scores:Postoperative outcome of liver transplantation

BACKGROUND Liver transplantation aims to increase the survival of patients with end-stage liver diseases and improve their quality of life.The number of organs available for transplantation is lower than the demand.To provide fair organ distribution,predictive mortality scores have been developed.AIM To compare the Acute Physiology and Chronic Health Evaluation IV(APACHE IV),balance of risk(BAR),and model for end-stage liver disease(MELD)scores as predictors of mortality.METHODS Retrospective cohort study,which included 283 adult patients in the postoperative period of deceased donor liver transplantation from 2014 to 2018.RESULTS The transplant recipients were mainly male,with a mean age of 58.1 years.Donors were mostly male,with a mean age of 41.6 years.The median cold ischemia time was 3.1 hours,and the median intensive care unit stay was 5 days.For APACHE IV,a mean of 59.6 was found,BAR 10.7,and MELD 24.2.The 28-day mortality rate was 9.5%,and at 90 days,it was 3.5%.The 28-day mortality prediction for APACHE IV was very good[area under the curve(AUC):0.85,P<0.001,95%CI:0.76-0.94],P<0.001,BAR(AUC:0.70,P<0.001,95%CI:0.58–0.81),and MELD(AUC:0.66,P<0.006,95%CI:0.55-0.78),P<0.008.At 90 days,the data for APACHE IV were very good(AUC:0.80,P<0.001,95%CI:0.71–0.90)and moderate for BAR and MELD,respectively,(AUC:0.66,P<0.004,95%CI:0.55–0.77),(AUC:0.62,P<0.026,95%CI:0.51–0.72).All showed good discrimination between deaths and survivors.As for the best value for liver transplantation,it was significant only for APACHE IV(P<0.001).CONCLUSION The APACHE IV assessment score was more accurate than BAR and MELD in predicting mortality in deceased donor liver transplant recipients.

Induced pluripotent stem cells: Mechanisms, achievements and perspectives in farm animals

Pluripotent stem cells are unspecialized cells withunlimited self-renewal, and they can be triggered to differentiate into desired specialized cell types. These features provide the basis for an unlimited cell source for innovative cell therapies. Pluripotent cells also allow to study developmental pathways, and to employ them or their differentiated cell derivatives in pharmaceutical testing and biotechnological applications. Via blastocyst complementation, pluripotent cells are a favoured tool for the generation of genetically modified mice. The recently established technology to generate an induced pluripotency status by ectopic co-expression of the transcription factors Oct4, Sox2, Klf4 and c-Myc allows to extending these applications to farm animal species, for which the derivation of genuine embryonic stem cells was not successful so far. Most induced pluripotent stem(i PS) cells are generated by retroviral or lentiviral transduction of reprogramming factors. Multiple viral integrations into the genome may cause insertional mutagenesis and may increase the risk of tumour formation. Non-integration methods have been reported to overcome the safety concerns associated with retro and lentiviral-derived i PS cells, such as transient expression of the reprogramming factors using episomal plasmids, and direct delivery of reprogramming m RNAs or proteins. In this review, we focus on the mechanisms of cellular reprogramming and current methods used to induce pluripotency. We also highlight problems associated with the generation of i PS cells. An increased understanding of the fundamental mechanisms underlying pluripotency and refining the methodology of i PS cell generation will have a profound impact on future development and application in regenerative medicine and reproductive biotechnology of farm animals.

The Negative Effect of Heavy Metal Salts on the Body of Mammal Animals

The main purpose of this presented article was to explain the need to study the amount of heavy metal salts in the environment where animals live, in the water, in air, and in the food and fodder consumed. This article presents materials from the literature on the effects of heavy metal salts on the body of animals and the environment in which they live. The cited analytical data showed that the general information on the negative effects of heavy metal salts on the body is sufficient, but their effects on the digestive tract and morpho-functional properties of rabbits should be studied in depth. Therefore, we planned to focus our scientific work on this topic. The article mainly refers to salts of heavy metals cadmium, lead, and mercury (Cd, Pb, Hg). It is noted in the literature that heavy metal salts have a negative effect on the body of animals. We focused mainly on data on the effects of heavy metals on farm animals, including rabbits. But it is clear that the authors referred to were referring to experimental animals. These negative effects are manifested in the form of disorders of digestive functions, disorders of neurovegetative processes, increasing incidence of cardiovascular disease, rapid heart failure, deterioration of calcium metabolism, as well as impaired haemoglobin metabolism. Disorders of protein metabolism manifest themselves in the form of cases of hyperproteinaemia and dysproteinaemia. The results of the evaluation of the organism of healthy animals in chemically and radioactively contaminated areas showed the accumulation of significant levels of chemical elements in their organism. We mainly looked at the effects of heavy metal salts on farm animals. The cited analytical data showed that the general information on the negative effects of heavy metal salts on the body is sufficient, but the effects on the activity of organ systems in the body (respiration, blood and blood circulation, digestion, reproduction, productivity and immunological systems) have not been comprehensively studied.