Animal Models Of Human Disease Research Articles

Single-step generation of rabbits carrying a targeted allele of the tyrosinase gene using CRISPR/Cas9.

Targeted genome editing of nonrodent mammalian species has provided the potential for highly accurate interventions into gene function in humans and the generation of useful animal models of human diseases. Here we show successful clustered regularly interspaced short palindromic repeat (CRISPR) and CRISPR-associated (Cas)-mediated gene targeting via circular plasmid injection in rabbits. The rabbit tyrosinase gene (TYR) was effectively disrupted, and we confirmed germline transmission by pronuclear injection of a circular plasmid expressing humanized Cas9 (hCas9) and single-guide RNA. Direct injection into pronuclear stage zygotes was possible following an in vitro validation assay. Neither off-target mutagenesis nor hCas9 transgenesis was detected in any of the genetically targeted pups and embryos examined. Gene targeting with this rapid and simplified strategy will help accelerate the development of translational research using other nonrodent mammalian species.

Stem cells in canine spinal cord injury--promise for regenerative therapy in a large animal model of human disease.

The use of cell transplantation for spinal cord injury is a rapidly evolving field in regenerative medicine. Numerous animal models are currently being used. However, translation to human patients is still a challenging step. Dogs are of increasing importance as a translational model for human disease since there is a greater awareness of the need to increase the quality of preclinical data. The use of dogs ultimately brings benefit to both human and veterinary medicine. In this review we analyze experimental and clinical studies using cell transplantation for canine spinal cord injury. Overall, in experimental studies, transplantation groups showed improvement over control groups. Improvements were measured at the functional, electrophysiological, histological, RNA and protein levels. Most clinical studies support beneficial effects of cell transplantation despite the fact that methodological limitations preclude definitive conclusions. However, the mechanisms of action and underlying the behavior of transplanted cells in the injured spinal cord remain unclear. Overall, we conclude here that stem cell interventions are a promising avenue for the treatment of spinal cord injury. Canines are a promising model that may help bridge the gap between translational research and human clinical trials.

Animal model of human disease with optic neuritis: neuropapillitis in a rat model infected with Angiostrongylus cantonensis.

Human Angiostrongylus cantonensis (A. cantonensis) is a food-borne parasitic disease and can cause optic neuritis. Increasing clinical angiostrongyliasis cases with optic neuritis have been reported, but the pathogenesis has not been fully understood until now. Here, we applied rats with A. cantonensis infection as an animal model to study the pathogenesis of optic neuritis caused by the infection. We observed that the optic disk of experimental rats appeared hyperemic, the retina vein became thick, and the visual evoked potential (VEP) latency was prolonged. There were obvious inflammatory cell infiltration in the retina and optic nerve adventitia followed with obvious optic nerve fiber demyelination and retina ganglion swelling. We also evaluated the effect of dexamethasone combined with albendazole on optic neuritis of rats infected with A. cantonensis. The results showed it had no obvious effect to prevent progressive visual deterioration for optic neuritis caused by A. cantonensis. The studies provided evidence that the pathogenesis of optic neuritis in infected rats was correlated to optic nerve demyelination and ganglion cell damage caused by optic nerve inflammation, and the common therapy to this disease was not so effective. Based on the above results, it may be necessary to combine neuroprotective agents with common therapy to treat and protect optic nerve and ganglion cells from their secondary injury.

A reporter mouse line with doxycyclin-inducible expression of β-glucosidase.

Mouse lines allowing the inducible expression of transgenes became essential tools for studying gene function and for developing accurate animal models for human diseases. A key component of this tool is the availability of "reporter" lines, mice expressing transgenes encoding easily detectable enzymes or other proteins normally not associated with eukaryotic tissues. Such lines may be suitable for a number of applications, including lineage tracing, label-retaining experiments, and the identification and monitoring of regulatory elements important for tissue-specific gene expression. However, only a limited number of reporter lines suitable for inducible expression systems are available. Here, we employed pronuclear DNA microinjection to generate a new reporter mouse line that allows the inducible expression of β-glucosidase, a recently reported stable and easily detectable protein, upon administration of doxycyclin to the drinking water. This novel line was established in the widely used inbreed background C57BL/6, and the transgene is transmitted between generations in a Mendelian fashion. When crossed to a K14-rtTA mouse line, activation of β-glucosidase expression in the epidermal basal layer is easily detected in double-transgenic animals receiving doxycyclin, while no expression is seen in double-transgenic mice without doxycyclin treatment or in animals carrying only one transgene. We anticipate that this new mouse line will become a valuable tool for a number of applications in vivo, including label-retaining experiments and testing the appropriate regulation of rtTA cassettes under different promoters in novel transgenic mouse lines.

Novel Approach to the Role of NMDA Receptors in Traumatic Brain Injury

For more than two decades the intensive research effort on the role of NMDA receptors (NMDAR) in traumatic brain injury (TBI) and cerebral ischemia (stroke) was led by the observations that extracellular concentrations of glutamate and aspartate are elevated after the insult and play a major role in brain pathologies. Indeed, NMDAR antagonists were shown to improve post-injury recovery in animal models and subsequently, large scale placebo-controlled clinical trials in TBI and stroke were performed with NMDAR antagonists. However, all these trials have demonstrated either no benefit or even deleterious effects. The discrepancy between the animal and human studies prompted us to investigate the temporal changes of the NMDAR after brain insult in TBI and stroke mouse models. We found that the early hyperactivation of the NMDAR is followed by loss of functional NMDAR which persists for weeks. Such dynamic changes could well explain the discrepancies between the preclinical and clinical experience as well as suggest alternative modes of treatment, namely, activation, rather than blockade of the NMDAR in the sub-acute period after TBI and stroke. Stimulation of the glycine modulatory site of the glycine/NMDAR by the partial agonist Dcycloserine (DCS) when given at least 24 hrs after TBI or stroke was shown to improve recovery of neurobehavioral and cognitive functions. It was also shown to restore impaired hippocampal Long-Term potentiation (LTP) and induce expression of Brain Derived-Neurotrophic Factor (BDNF) in a TBI model and to improve somatosensory and cognitive function in a stroke model. Experiments to optimize the DCS treatment paradigm showed that similar benefits were demonstrated in TBI mice whether the drug was given as a single injection at 24 or 72 hrs post injury, or as double (24 and 48 hrs) or triple (24, 48 and 72 hrs) doses. Interestingly, beneficial effects of DCS were reported in a range of animal models of human diseases as well as in several clinical indications thought to involve disruptions in NMDAR function, such as drug addiction, post-traumatic stress disorder, Parkinson's disease, aging and psychiatric disorders. As DCS has a good safety profile, and is already in use in humans in several different indications, and based on studies with DCS in the mouse TBI model, a multi-center prospective randomized controlled clinical trial, aiming to assess the effect of a single dose of DCS on cognitive outcome in patients with moderate TBI has recently begun.

Feasibility of a CdTe-based SPECT for high-resolution low-dose small animal imaging: a Monte Carlo simulation study

Dedicated single-photon-emission computed tomography(SPECT) systems based on pixelated semiconductors such as cadmium telluride(CdTe) are in development to study small animal models of human disease. Inan effort to develop a high-resolution, low-dose system for small animalimaging, we compared a CdTe-based SPECT system and a conventionalNaI(Tl)-based SPECT system in terms of spatial resolution, sensitivity,contrast, and contrast-to-noise ratio (CNR). In addition, we investigatedthe radiation absorbed dose and calculated a figure of merit (FOM) for bothSPECT systems. Using the conventional NaI(Tl)-based SPECT system, weachieved a spatial resolution of 1.66 mm at a 30 mm source-to-collimatordistance, and a resolution of 2.4-mm hot-rods. Using the newly-developedCdTe-based SPECT system, we achieved a spatial resolution of 1.32 mm FWHM ata 30 mm source-to-collimator distance, and a resolution of 1.7-mm hot-rods.The sensitivities at a 30 mm source-to-collimator distance were 115.73 counts/sec/MBq and 83.38 counts/sec/MBq for the CdTe-based SPECT andconventional NaI(Tl)-based SPECT systems, respectively. To comparequantitative measurements in the mouse brain, we calculated the CNR forimages from both systems. The CNR from the CdTe-based SPECT system was 4.41,while that from the conventional NaI(Tl)-based SPECT system was 3.11 whenthe injected striatal dose was 160 Bq/voxel. The CNR increased as a functionof injected dose in both systems. The FOM of the CdTe-based SPECT system wassuperior to that of the conventional NaI(Tl)-based SPECT system, and thehighest FOM was achieved with the CdTe-based SPECT at a dose of 40 Bq/voxelinjected into the striatum. Thus, a CdTe-based SPECT system showedsignificant improvement in performance compared with a conventional systemin terms of spatial resolution, sensitivity, and CNR, while reducing theradiation dose to the small animal subject. Herein, we discuss thefeasibility of a CdTe-based SPECT system for high-resolution, low-dose smallanimal imaging.

Allele-specific genome editing and correction of disease-associated phenotypes in rats using the CRISPR-Cas platform.

The bacterial CRISPR/Cas system has proven to be an efficient gene-targeting tool in various organisms. Here we employ CRISPR/Cas for accurate and efficient genome editing in rats. The synthetic chimeric guide RNAs (gRNAs) discriminate a single-nucleotide polymorphism (SNP) difference in rat embryonic fibroblasts, allowing allele-specific genome editing of the dominant phenotype in (F344 × DA)F1 hybrid embryos. Interestingly, the targeted allele, initially assessed by the allele-specific gRNA, is repaired by an interallelic gene conversion between homologous chromosomes. Using single-stranded oligodeoxynucleotides, we recover three recessive phenotypes: the albino phenotype by SNP exchange; the non-agouti phenotype by integration of a 19-bp DNA fragment; and the hooded phenotype by eliminating a 7,098-bp insertional DNA fragment, evolutionary-derived from an endogenous retrovirus. Successful in vivo application of the CRISPR/Cas system confirms its importance as a genetic engineering tool for creating animal models of human diseases and its potential use in gene therapy.

Zebrafish as a Model System to Study Skin Biology and Pathology

INTRODUCTION Several animal models have been developed to recapitulate the features of specific skin diseases, and such model systems have provided valuable insight into the pathomechanistic details of these diseases. They have also provided useful systems for testing of treatment modalities for a number of conditions. The preferred platform for such model development has been the mouse, often through the development of “knockout” mice or by development of transgenic mice with expression of the mutant genes. Although the mouse models have often demonstrated remarkable similarity to human diseases, mice as a model system have considerable limitations, including relatively long lifespan and high cost of development. Also, the genetic background of the mouse strains can have a major influence on the development of the disease phenotype. In some cases, development of the mouse model is not feasible because of the absence of the corresponding gene in the mouse genome. These considerations, particularly in conjunction with cost-containment issues, have prompted the search for an alternative model system to study skin diseases. In fact, Vanchieri (2001) suggested, “Move over mouse: make way for the woodchucks, ferrets, and zebrafish,” and Lieschke and Currie (2007) said, “Animal models of human disease: zebrafish swim into view.”

The effect of mammary gland-specific transgene expression on rabbit reproductive gland structure.

Transgenic rabbits are excellent animal models for human diseases and suitable bioreactors for the production of recombinant proteins on an experimental and commercial scale. The aim of this study was to compare the structure of the mWAP-hFVIII transgenic and non-transgenic rabbit ovarian and testicular tissue. Ovarian and testicular tissue samples were taken from transgenic and non-transgenic New Zealand White rabbits, examined by optical microscopy and analyzed morphometrically. An increase of the relative volume of primary follicles and a decrease of the relative volume of antral follicles was detected in the transgenic ovarian structure (P < 0.05), but other developmental follicular stages and follicular diameters were not affected (P > 0.05). In the testes a significant decrease (P < 0.05) of the epithelial height was detected in the transgenic testicular structure, but the relative volume of all basic structures (germinal epithelium, interstitium and lumen) was unaltered (P > 0.05). Generally, this study demonstrates a weak negative effect of mWAP-hFVIII transgenesis on rabbit gonadal structure.

Characterization of the canine urinary proteome.

Urine is an attractive biofluid for biomarker discovery as it is easy and minimally invasive to obtain. While numerous studies have focused on the characterization of human urine, much less research has focused on canine urine. The objectives of this study were to characterize the universal canine urinary proteome (both soluble and exosomal), to determine the overlap between the canine proteome and a representative human urinary proteome study, to generate a resource for future canine studies, and to determine the suitability of the dog as a large animal model for human diseases. The soluble and exosomal fractions of normal canine urine were characterized using liquid chromatography tandem mass spectrometry (LC-MS/MS). Biological Networks Gene Ontology (BiNGO) software was utilized to assign the canine urinary proteome to respective Gene Ontology categories, such as Cellular Component, Molecular Function, and Biological Process. Over 500 proteins were confidently identified in normal canine urine. Gene Ontology analysis revealed that exosomal proteins were largely derived from an intracellular location, while soluble proteins included both extracellular and membrane proteins. Exosome proteins were assigned to metabolic processes and localization, while soluble proteins were primarily annotated to specific localization processes. Several proteins identified in normal canine urine have previously been identified in human urine where these proteins are related to various extrarenal and renal diseases. The results of this study illustrate the potential of the dog as an animal model for human disease states and provide the framework for future studies of canine renal diseases.

Why human disease-associated residues appear as the wild-type in other species: genome-scale structural evidence for the compensation hypothesis.

Many human-disease associated amino acid residues (DARs) appear as the wild-type in other species. This phenomenon is commonly explained by the presence of compensatory residues in these other species that alleviate the deleterious effects of the DARs. The general validity of this hypothesis, however, is unclear, because few compensatory residues have been identified. Here we test the compensation hypothesis by assembling and analyzing 1,077 DARs located in 177 proteins of known crystal structures. Because destabilizing protein structures is a primary reason why DARs are deleterious, we focus on protein stability in this analysis. We discover that, in species where a DAR represents the wild-type, the destabilizing effect of the DAR is generally lessened by the observed amino acid substitutions in the spatial proximity of the DAR. This and other findings provide genome-scale evidence for the compensation hypothesis and have important implications for understanding epistasis in protein evolution and for using animal models of human diseases.

Poster #M173 STUDYING HEART ARRHYTHMIAS IN RELATION TO PSYCHOSIS (SHARP). INCREASED PREVALENCE OF CARDIAC ARRHYTHMIAS IN RECENT ONSET SCHIZOPHRENIA

The development and use of UHPLC-based methods for the identification, validation and analysis of biomarkers for diseases is reviewed. The currents trends in types of stationary phases and modes of detection are discussed. Afterwards, examples are provided on the use of UHPLC-MS for finding novel biomarkers in samples from in vitro or in vivo animal models of human diseases, as well as in biofluid samples (mainly urine and plasma) obtained from patients. Molecular profiling and targeted analysis are considered, providing an overview of recent experimental or clinical works carried out using UHPLC analysis of compounds from various chemical classes, such as low molecular weight metabolites, hormones, lipids, peptides and proteins.

Maternal–fetal tolerance and parturition

Journal of Reproductive Immunology 101–102 (2014) 6–17 11 with the Bishop of Oxford Samuel Wilberforce concerning the validity of Darwin’s theory of evolution. It was the liberating force of science versus the authoritarian view of religion that Man was a unique creation of God, and hence distinct and different from all animal species. Sciencewon.As yet, there are still somewhosteadfastly refuse to consider that what has been learned from the study of pregnancy in animals has any relevance towhat happens in human reproduction and its maladies. This has not had an impact on the increasing amounts of grant monies given to the study of animal models of human disease. In this debate, it is first necessary to review the proper use of animal analogmodels of human disease, and to emphasize the fallacy of uncritical extrapolation from animals to humans. Nevertheless, careful consideration of the structure and composition of the feto-maternal interface in mice, rats, and humans indicates rather striking homologies. Indeed, the similarities appear to outweigh the differences, save for minor details. Further, an in-depth consideration of the implications of a currently popular hypothesis concerning the function of humanuterineNK cells at the feto-maternal interface in healthy and disordered pregnancy appears to reveal a major flaw in the proposed mechanism and its importance. Indeed, the existing data support the alternative view that findings in animal models may indeed be quite relevant to human pregnancy problems. The importance of a rigorous scientific approach to the use of both animal and human data is emphasized. http://dx.doi.org/10.1016/j.jri.2013.12.015

Crazy Like a Fox

Animal models of human disease play a central role in modern biomedical science. Developing animal models for human mental illness presents unique practical and philosophical challenges. In this article we argue that (1) existing animal models of psychiatric disease are not valid, (2) attempts to model syndromes are undermined by current nosology, (3) models of symptoms are rife with circular logic and anthropomorphism, (4) any model must make unjustified assumptions about subjective experience, and (5) any model deemed valid would be inherently unethical, for if an animal adequately models human subjective experience, then there is no morally relevant difference between that animal and a human.

Concise Review: Drug Discovery in the Age of the Induced Pluripotent Stem Cell

For decades, the paradigm of drug discovery and development has relied on immortalized cell lines, animal models of human disease, and clinical trials. With the discovery of induced pluripotent stem cell (iPSC) technology in 2007, a new human in vitro drug testing platform has potentially augmented this set of tools by providing additional ways to screen compounds for safety and efficacy. The growing number of human disease models made with patient-specific iPSCs has made it possible to conduct research on a wide range of disorders, including rare diseases and those with multifactorial origin, as well as to simulate drug effects on difficult-to-obtain tissues such as brain and cardiac muscle. Toxicity and teratogenicity assays developed with iPSC-derived cells can also provide an additional layer of safety before advancing drugs to clinical trials. The incorporation of iPSC technology into drug therapy development holds promise as a more powerful and nuanced approach to personalized medicine.

What animals can teach clinicians about the hippocampus.

Abnormalities in hippocampal structure and function have been reported in a number of human neuropathological and neurodevelopmental disorders, including Alzheimer's disease, autism spectrum disorders, Down syndrome, epilepsy, and schizophrenia. Given the complexity of these disorders, animal studies are invaluable and remain to date irreplaceable, providing fundamental knowledge regarding the basic mechanisms underlying normal and pathological human brain structure and function. However, there is a prominent ill-conceived view in current research that scientists should be restricted to using animal models of human diseases that can lead to results applicable to humans within a few years. Although there is no doubt that translational studies of this kind are important and necessary, limiting animal studies to applicable questions is counterproductive and will ultimately lead to a lack of knowledge and an inability to address human health problems. Here, we discuss findings regarding the normal postnatal development of the monkey hippocampal formation, which provide an essential framework to consider the etiologies of different neuropathological disorders affecting human hippocampal structure and function. We focus on studies of gene expression in distinct hippocampal regions that shed light on some basic mechanisms that might contribute to the etiology of schizophrenia. We argue that researchers, as well as clinicians, should not consider the use of animals in research only as 'animal models' of human diseases, as they will continue to need and benefit from a better understanding of the normal structure and functions of the hippocampus in 'model animals'.

Genetic substructure in cynomolgus macaques (Macaca fascicularis) on the island of Mauritius.

BackgroundNonhuman primates are commonly used in biomedical research as animal models of human disease and behavior. Compared to common rodent models, nonhuman primates are genetically, physiologically, behaviorally and neurologically more similar to humans owing to more recent shared ancestry and therefore provide the advantage of greater translational validity in preclinical studies. The cynomolgus macaque (Macaca fascicularis) is one of the most commonly used nonhuman primates in academic and industry settings, yet population genetic research has revealed significant substructure throughout the species distribution that may confound studies. Cynomolgus monkeys introduced to Mauritius specifically have previously been thought to maintain the least genetic heterogeneity of all cynomolgus monkeys, although recent work, including work from our lab, suggests macaques from Mauritius too may harbor cryptic substructure.ResultsTo evaluate putative substructure in Mauritian cynomolgus macaques, we designed a panel of 96 single nucleotide polymorphisms based on preliminary findings from previous work to screen 246 of cynomolgus monkeys from two primary suppliers. Results from this study support substructure in Mauritian macaques and suggest a minimum of two populations and maybe three on Mauritius, with moderate admixture.ConclusionThese findings inform the natural history of these monkeys suggesting either a previously unrecognized physical or ecological barrier to gene flow on Mauritius and/or the breakdown of historic substructure resulting from the history of macaque introduction to the island. These findings are relevant to ongoing research using these models in part because of increased appreciation of segregating common variation with functional effects and may be used to better inform animal selection in preclinical research.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-748) contains supplementary material, which is available to authorized users.

Genome editing with programmable site-specific nucleases

Genome editing is a cutting-edge technology that enables to modify the target gene using programmable site-specific nucleases, such as TALENs and CRISPR/Cas9. Currently, cell and animal models of human diseases have been competitively created throughout the world, because genome editing technology paved the way for genetic modifications even in cells and organisms that had been difficult to manipulate the genome. In this review, we introduce the basic principles and current situations of genome editing with programmable nucleases.

IEEE Access Special Section Editorial: Emerging Computed Tomography Technologies

X-ray computed tomography (CT) has a central role in clinical imaging, often as the first and only imaging study before definitive intervention for a wide variety of conditions. X-ray micro-CT is similarly important in preclinical imaging with anatomically and physiologically relevant small animal models of human diseases. The field of X-ray CT is entering another Spring. Buds are blooming in the areas of X-ray sources such as those based on carbon nanotubes (CNTs) or free-electron lasers; detectors, especially photon-counting modules; X-ray gratings; contrast agents; compressive sensing (CS); and reconstruction methods. Synergistically, these innovations can be integrated to revolutionize the CT field, achieving a quantum leap in performance for biomedical applications.

Achilles tendon injuries in elite athletes: lessons in pathophysiology from their equine counterparts.

Superficial digital flexor tendon (SDFT) injury in equine athletes is one of the most well-accepted, scientifically supported companion animal models of human disease (i.e., exercise-induced Achilles tendon [AT] injury). The SDFT and AT are functionally and clinically equivalent (and important) energy-storing structures for which no equally appropriate rodent, rabbit, or other analogues exist. Access to equine tissues has facilitated significant advances in knowledge of tendon maturation and aging, determination of specific exercise effects (including early life), and definition of some of the earliest stages of subclinical pathology. Access to human surgical biopsies has provided complementary information on more advanced phases of disease. Importantly, equine SDFT injuries are only a model for acute ruptures in athletes, not the entire spectrum of human tendonopathy (including chronic tendon pain). In both, pathology begins with a potentially prolonged phase of accumulation of (subclinical) microdamage. Recent work has revealed remarkably similar genetic risk factors, including further evidence that tenocyte dysfunction plays an active role. Mice are convenient but not necessarily accurate models for multiple diseases, particularly at the cellular level. Mechanistic studies, including tendon cell responses to combinations of exercise-associated stresses, require a more thorough investigation of cross-species conservation of key stress pathway auditors. Molecular evidence has provided some context for the poor performance of mouse models; equines may provide better systems at this level. The use of horses may be additionally justifiable based on comparable species longevity, lifestyle factors, and selection pressure by similar infectious agents (e.g., herpesviruses) on general cell stress pathway evolution.