In Vivo Quantitative Assessment of Myocardial Structure,Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that MicroCT provides quantitative high-resolution three-dimensional (3D) anatomical data non-destructively and longitudinally. Most importantly, with the development of a novel preclinical iodinated contrast agent called eXIA160, functional and metabolic assessment of the heart became possible. However, prior to the advent of commercial MicroCT scanners equipped with X-ray flat-panel detector technology and easy-to-use cardio-respiratory gating, preclinical studies of cardiovascular disease (CVD) in small animals required a MicroCT technologist with advanced skills, and thus were impractical for widespread implementation. The goal of this work is to provide a practical guide to the use of the high-speed Quantum FX MicroCT system for comprehensive determination of myocardial global and regional function along with assessment of myocardial perfusion, metabolism and viability in healthy mice and in a cardiac ischemia mouse model induced by permanent occlusion of the left anterior descending coronary artery (LAD).     

The use of transgenic systems in pharmaceutical research.

Those pharmaceutical companies whose goal is to generate novel innovative drugs are faced with the challenge that only a fraction of the compounds tested in clinical trials eventually become a registered drug. This problem of attrition is compounded by the fact that the clinical trial or development stage is by far the most costly phase of bringing a new drug to market, consuming around 80 per cent of the total spend. Transgenic technology represents an attractive approach to reducing the attrition rate of compounds entering clinical trials by increasing the quality of the target and compound combinations making the transition from discovery into development. Transgenic technology can impact at many points in the discovery process, including target identification and target validation, and provides models designed to alert researchers early to potential problems with drug metabolism and toxicity, as well as providing better models for human diseases. In target identification, transgenic animals harbouring large DNA fragments can be used to narrow down genetic regions. Genetic studies often result in the identification of large genomic regions and one way to decrease the region size is to do complementation studies in transgenic animals using, for example, inserts from bacterial artificial chromosome (BAC) clones. In target validation, transgenic animals can be used for in vivo validation of a specific target. Considerable efforts are being made to establish new, rapid and robust tools with general utility for in vivo validation, but, so far, only transgenic animals work reliably on a wide range of targets. Transgenic animals can also be used to generate better disease models. Predictive animal models to test new compounds and targets will significantly speed up the drug discovery process and, more importantly, increase the quality of the compounds taken further in the research and development process. Humanised transgenic animals harbouring the human target molecule can be used to understand the effect of a compound acting on the human target in vivo. Also, models mimicking human drug metabolism will provide a means of assessing the effect of human-specific metabolites and of understanding the pharmacokinetic properties of potential drugs. In toxicology studies, transgenic animals are providing more predictive models. A good example of this are those models routinely used to look for carcinogenicity associated with new compounds.     

The wobbler mouse

Various mutations in humans and animals lead to the selective and progressive degeneration of motoneurons, resulting in muscular weakness, subsequent paralysis, and death (1-3). Amyotrophic lateral sclerosis (ALS) is the most common adult human motoneuron disease, but the vast majority of sporadic and familial cases of ALS are still of unknown origin (4). Murine models of motoneuron diseases, derived from spontaneous mutations in the colonies, have been known for half a century. Prior to the first identifications of the mutated proteins in human ALS, they have largely been used to explore the disease etiology. The chromosomal localization of these mutations does not favor a genetic similarity between these murine models and the few human forms of the disease for which the mutation or the chromosomal localization is known. Yet the fact that most human ALS cases are of unknown etiology and the recent discovery of molecules with no known role in motoneuron survival (5-7), indicate that these murine mutants may still contribute to the understanding of motoneuronal degenerative processes. This can be exemplified by the work performed on the wobbler mouse, one of the oldest and most extensively studied models, which is reviewed here.     

Knowledge and Perceptions of Macedonian Hunters and Herders: The Influence of Species Specific Ecology of Bears, Wolves, and Lynx

The fact that human—large carnivore relationships tend to be full of material and social conflicts raises applied questions concerning the origin of human perceptions linked to these animals and more theoretical questions concerning the link between identification and relational processes. This study, based on ethno-ethological surveys in the Republic of Macedonia (SE Europe), aims to show that the widely contrasting species specific behavioural characteristics of brown bears, wolves and Eurasian lynx influence local perceptions of these species through the nature and frequency of their interactions with humans. It appears that a high frequency of interactions allows the relational processes to dominate, leading people to modify their actions in response to the behaviour and ecology of the species. However, the fact that the virtual absence of interactions with lynx has not prevented the construction of a particular image of the species also highlights the complexity of the relationship between the level of interactions and people’s perception about animals.     

Structure,function and evolution of the animal mitochondrial replicative DNA helicase

The mitochondrial replicative DNA helicase is essential for animal mitochondrial DNA (mtDNA) maintenance. Deleterious mutations in the gene that encodes it cause mitochondrial dysfunction manifested in developmental delays, defects and arrest, limited life span, and a number of human pathogenic phenotypes that are recapitulated in animals across taxa. In fact, the replicative mtDNA helicase was discovered with the identification of human disease mutations in its nuclear gene, and based upon its deduced amino acid sequence homology with bacteriophage T7 gene 4 protein (T7 gp4), a bi-functional primase-helicase. Since that time, numerous investigations of its structure, mechanism, and physiological relevance have been reported, and human disease alleles have been modeled in the human, mouse, and Drosophila systems. Here, we review this literature and draw evolutionary comparisons that serve to shed light on its divergent features.     

A review of spontaneous ulcer disease in domestic animals: chickens, cattle, horses, and swine.

The human species is perhaps unique for its high incidence of spontaneous, chronic ulcer of the glandular mucosa of the stomach and duodenum. Nevertheless, spontaneous ulcers, usually of the stomach, commonly occur in many domestic animals. Some of these lesions are chronic and they may occur in either the glandular or squamous-lined regions of the stomach. As with the human disease(s) the pathogenesis in domestic animals is multifactorial, poorly understood, and variable between and within species. Some parallelisms exist in aggressive and defensive factors, but parasitic factors, via gastrinemia, and a histaminic factor via diet may occur in some animal ulcers. Underlying environmental stresses, of debated importance with the human disease but of proven importance in several rat ulcer models, may play a key role in some spontaneous gastric ulcer situations in swine and cattle. This is manifest in crowding and transporting situations. Seasonal, age, and weaning factors also alter the incidence of ulcer in cattle. Psychologic/environmental stress-related factors, as well as drug and physiologic stress factors appear to upset the balance in the horse between resistance and aggressive mucosal factors. Dietary factors which are highly important in ulcer disease in swine and chickens, have not yet been incriminated in spontaneous, equine ulcer disease. More investigation of the pathogenesis of domestic animal ulcers will prove useful for both human and veterinary medicine in terms of a) elucidating pathogenetic mechanisms for all species, b) may provide new animal models for study, and c) may enhance prevention of such lesions in domestic animals for economic and humanitarian reasons.     

The electrical resistance of the lungs,intercostal muscles,and kidneys in hypertensive ISIAH rats

A comparative study of the bioelectrical impedance of normotensive and hypertensive animal tissues was carried out. It was found that the electrical resistance of kidneys, lungs, and intercostal muscles in rats with arterial hypertension (ISIAH strain) was significantly lower than in normotensive Wistar rats, which indicates that the volume of circulating blood and the total amount of fluid were increased in animals with arterial hypertension. The fact that the resistance of the conducting medium is decreased in arterial hypertension should be taken into account in the analysis of cardioelectric potentials on the body surface and electrocardiograms in conventional leads, as well as for the purposes of the development of heterogeneous torso models and for verification of recovery algorithms for electrical properties of chest tissues.     

大鼠、豚鼠和金黄地鼠的尿液蛋白质组比较

生物标志物是指与生理或病理变化相关的可监测的变化。尿液作为机体的一种排泄物,不受稳态机制的调节,可以反映机体的多种变化。动物模型可以模拟人类疾病过程,监测疾病的变化,并为早期诊断提供线索。大鼠作为常用的模型动物并非所有疾病的优势模型动物,因此比较大鼠与其他动物的尿液蛋白质组,从而为其他疾病选择优势模型动物提供线索。文中通过膜上酶切切成肽段再通过液相色谱与串联质谱偶联技术(LC-MS/MS)分析肽段信息,比较大鼠、豚鼠和金黄地鼠的尿液蛋白,结果显示3种鼠的尿蛋白数量不同,在机体不同系统中表达情况不同,参与的生物功能也不同。这为不同疾病选择不同的优势模型动物提供了依据。     

Stem cells, regenerative medicine, and animal models of disease

The field of stem cell biology and regenerative medicine is rapidly moving toward translation to clinical practice, and in doing so has become even more dependent on animal donors and hosts for generating cellular reagents and assaying their potential therapeutic efficacy in models of human disease. Advances in cell culture technologies have revealed a remarkable plasticity of stem cells from embryonic and adult tissues, and transplantation models are now needed to test the ability of these cells to protect at-risk cells and replace cells lost to injury or disease. With such a mandate, issues related to acceptable sources and controversial (e.g., chimeric) models have challenged the field to provide justification of their potential efficacy before the passage of new restrictions that may curb anticipated breakthroughs. Progress from the use of both in vitro and in vivo regenerative medicine models already offers hope both for the facilitation of stem cell phenotyping in recursive gene expression profile models and for the use of stem cells as powerful new therapeutic reagents for cancer, stroke, Parkinson's, and other challenging human diseases that result in movement disorders. This article describes research in support of the following three objectives: (1) To discover the best stem or progenitor cell in vitro protocols for isolating, expanding, and priming these cells to facilitate their massive propagation into just the right type of neuronal precursor cell for protection or replacement protocols for brain injury or disease, including those that affect movement such as Parkinson's disease and stroke; (2) To discover biogenic factors--compounds that affect stem/progenitor cells (e.g., from high-throughput screening and other bioassay approaches)--that will encourage reactive cell genesis, survival, selected differentiation, and restoration of connectivity in central nervous system movement and other disorders; and (3) To establish the best animal models of human disease and injury, using both small and large animals, for testing new regenerative medicine therapeutics.     

Hydrophobia, lectin binding, and molecular order in the stratum corneum of adult and neonatal rats and in human breast cells in culture.

A search for differences due to ANS staining (hydrophobia), Con A and PNA binding capacity, and birefringence was carried out on stratified epithelia of rat skin and human breast cells (HBC) in culture. Microfluorimetric measurements confirm that the ANS fluorescence of the stratum corneum from adults is higher than that of newborns. HBC exhibited an unexpected deep ANS-fluorescence. Differences in the binding capacity of the epithelial layers to Con A and PNA were detected with advancing age. Retardation measurements revealed that the form birefringence of the stratum corneum is higher in adult animals specially as revealed by the fact that its form birefringence curve branch from n = 1.414 to n = 1.479 is steeper, i.e. depict higher values. The strong birefringence of the cytoplasmic tonofilaments presented by cultured human breast cells was considered an unexpected finding and attributed to changes that the cells underwent following the in vitro conditions.     

The tree shrews: adjuncts and alternatives to primates as models for biomedical research

The tree shrews are non-rodent, primate-like, small animals. There is increasing interest in using them to establish animal models for medical and biological research. This review focuses on the use of the tree shrews in in vivo studies on viral hepatitis, hepatocellular carcinoma (HCC), myopia, and psychosocial stress. Because of the susceptibility of the tree shrews (Tupaia belangeri) and their hepatocytes to infection with human hepatitis B virus (HBV) in vivo and in vitro, these animals have been used to establish human hepatitis virus-induced hepatitis and human HBV- and aflatoxin B1-associated HCC models. As these animals are phylogenetically close to primates in evolution and have a well-developed visual system and color vision in some species, they have been utilized to establish myopia models. Because dramatic behavioral, physiological, and neuroendocrine changes in subordinate male tree shrews are similar to those observed in depressed human patients, the tree shrews have been successfully employed to experimentally study psychosocial stress. However, the tree shrews holds significant promise as research models and great use could be made of these animals in biomedical research.     

Diabetes, metallothionein, and zinc interactions: a review

Epidemiological evidence, associating diabetes with zinc (Zn) deficiencies, has resulted in numerous research studies describing the effects of Zn and associated metallothionein (MT), on reducing diabetic complications associated with oxidative stress. MT has been found to have a profound effect on the reduction of oxidative stress induced by the diabetic condition. Over expression of MT in various metabolic organs has also been shown to reduce hyperglycaemia-induced oxidative stress, organ specific diabetic complications, and DNA damage in diabetic experimental animals, which have been further substantiated by the results from MT-knockout mice. Additionally, supplementation with Zn has been shown to induce in vivo MT synthesis in experimental animals and to reduce diabetes related complications in both humans and animal models. Although the results are promising, some caution regarding this topic is however necessary, due to the fact that the majority of the studies done have been animal based. Hence more human intervention trials are needed regarding the positive effects of MT and Zn before firm conclusions can be made regarding their use in the treatment of diabetes.     

Animal models for IgE-meditated cancer immunotherapy

Although most monoclonal antibodies developed for cancer therapy are of the IgG class, antibodies of the IgE class have certain properties that make them attractive as cancer therapeutics. These properties include the superior affinity for the Fc epsilon receptors (FcεRs), the low serum level of IgE that minimizes competition of endogenous IgE for FcεR occupancy, and the ability to induce a broad and vigorous immune response through the interaction with multiple cells including mast cells, basophils, monocytes, macrophages, dendritic cells, and eosinophils. Tumor-targeted IgE antibodies are expected to harness the allergic response against tumors and activate a secondary, T-cell-mediated immune response. Importantly, the IgE antibody can be used for passive immunotherapy and as an adjuvant of cancer vaccines. However, there are important limitations in the use of animal models including the fact that human IgE does not interact with rodent FcεRs and that there is a different cellular distribution of FcεRs in humans and rodents. Despite these limitations, different murine models have been used with success to evaluate the in vivo anti-cancer activity of several IgE antibodies. These models include wild-type immunocompetent animals bearing syngeneic tumors, xenograft models using immunocompromised mice bearing human tumors and reconstituted with human effector cells, and human FcεRIα transgenic mice bearing syngeneic tumors. In addition, non-human primates such as cynomolgus monkeys can be potentially used for toxicological and pharmacokinetic studies. This article describes the advantages and disadvantages of these models and their use in evaluating the in vivo properties of IgE antibodies for cancer therapy.     

Induction of Tolerance to a Recombinant Human Enzyme,Acid Alpha-Glucosidase,in Enzyme Deficient Knockout Mice

When knockout mice are used to test the efficacy of recombinant human proteins, the animals often develop antibodies to the enzyme, precluding long-term pre-clinical studies. This has been a problem with a number of models, for example, the evaluation of gene or enzyme replacement therapies in a knockout model of glycogen storage disease type II (GSDII; Pompe syndrome). In this disease, the lack of acid alpha-glucosidase (GAA) results in lysosomal accumulation of glycogen, particularly in skeletal and cardiac muscle. Here, we report that in a GAA-deficient mouse model of GSDII, low levels of transgene-encoded human GAA expressed in skeletal muscle or liver dramatically blunt or abolish the immune response to human recombinant protein. Of two low expression transgenic lines, only the liver-expressing line exhibited a profound GAA deficiency in skeletal muscle and heart indistinguishable from that in the original knockouts. The study suggests that the induction of tolerance in animal models of protein deficiencies could be achieved by restricting the expression of a gene of interest to a particular, carefully chosen tissue.     

New commercial opportunities for advanced reproductive technologies in horses,wildlife, and companion animals

As advanced reproductive technologies become more efficient and repeatable in livestock and laboratory species, new opportunities will evolve to apply these techniques to alternative and non-traditional species. This will result in new markets requiring unique business models that address issues of animal welfare and consumer acceptance on a much different level than the livestock sector. Advanced reproductive technologies and genetic engineering will be applied to each species in innovative ways to provide breeders more alternatives for the preservation and propagation of elite animals in each sector. The commercialization of advanced reproductive techniques in these niche markets should be considered a useful tool for conservation of genetic material from endangered or unique animals as well as production of biomedical models of human disease.     

Characterization of the rat oncostatin m receptor complex which resembles the human, but differs from the murine cytokine receptor

Evaluation of a pathophysiological role of the interleukin-6-type cytokine oncostatin M (OSM) for human diseases has been complicated by the fact that mouse models of diseases targeting either OSM or the OSM receptor (OSMR) complex cannot fully reflect the human situation. This is due to earlier findings that human OSM utilizes two receptor complexes, glycoprotein 130 (gp130)/leukemia inhibitory factor receptor (LIFR) (type I) and gp130/OSMR (type II), both with wide expression profiles. Murine OSM on the other hand only binds to the gp130/OSMR (type II) receptor complex with high affinity. Here, we characterize the receptor usage for rat OSM. Using different experimental approaches (knock-down of the OSMR expression by RNA interference, blocking of the LIFR by LIF-05, an antagonistic LIF variant and stably transfected Ba/F3 cells) we can clearly show that rat OSM surprisingly utilizes both, the type I and type II receptor complex, therefore mimicking the human situation. Furthermore, it displays cross-species activities and stimulates cells of human as well as murine origin. Its signaling capacities closely mimic those of human OSM in cell types of different origin in the way that strong activation of the Jak/STAT, the MAP kinase as well as the PI3K/Akt pathways can be observed. Therefore, rat disease models would allow evaluation of the relevance of OSM for human biology.     

Animal models of diabetic retinopathy: doors to investigate pathogenesis and potential therapeutics

Effective and validated animal models are valuable to investigate the pathogenesis and potential therapeutics for human diseases. There is much concern for diabetic retinopathy (DR) in that it affects substantial number of working population all around the world, resulting in visual deterioration and social deprivation. In this review, we discuss animal models of DR based on different species of animals from zebrafish to monkeys and prerequisites for animal models. Despite criticisms on imprudent use of laboratory animals, we hope that animal models of DR will be appropriately utilized to deepen our understanding on the pathogenesis of DR and to support our struggle to find novel therapeutics against catastrophic visual loss from DR.     

Immunization with recombinant HLA classes I and II, HIV-1 gp140, and SIV p27 elicits protection against heterologous SHIV infection in rhesus macaques

Major histocompatibility complex (MHC) molecules expressed on the surface of human immunodeficiency virus (HIV) are potential targets for neutralizing antibodies. Since MHC molecules are polymorphic, nonself MHC can also be immunogenic. We have used combinations of novel recombinant HLA class I and II and HIV/simian immunodeficiency virus (SIV) antigens, all linked to dextran, to investigate whether they can elicit protective immunity against heterologous simian/human immunodeficiency virus (SHIV) challenge in rhesus macaques. Three groups of animals were immunized with HLA (group 1, n = 8), trimeric YU2 HIV type 1 (HIV-1) gp140 and SIV p27 (HIV/SIV antigens; group 2, n = 8), or HLA plus HIV/SIV antigens (group 3, n = 8), all with Hsp70 and TiterMax Gold adjuvant. Another group (group 4, n = 6) received the same vaccine as group 3 without TiterMax Gold. Two of eight macaques in group 3 were completely protected against intravenous challenge with 18 50% animal infective doses (AID₅₀) of SHIV-SF162P4/C grown in human cells expressing HLA class I and II lineages represented in the vaccine, while the remaining six macaques showed decreased viral loads compared to those in unimmunized animals. Complement-dependent neutralizing activity in serum and high levels of anti-HLA antibodies were elicited in groups 1 and 3, and both were inversely correlated with the plasma viral load at 2 weeks postchallenge. Antibody-mediated protection was strongly supported by the fact that transfer of pooled serum from the two challenged but uninfected animals protected two naïve animals against repeated low-dose challenge with the same SHIV stock. This study demonstrates that immunization with recombinant HLA in combination with HIV-1 antigens might be developed into an alternative strategy for a future AIDS vaccine.