Browsing by Subject "animal model"

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  • Quitt, Pia R.; Bruehschwein, Andreas; Matiasek, Kaspar; Wielaender, Franziska; Karkamo, Veera; Hytonen, Marjo K.; Meyer-Lindenberg, Andrea; Dengler, Berett; Leeb, Tosso; Lohi, Hannes; Fischer, Andrea (2021)
    Background Shaking puppy syndrome is commonly attributed to abnormal myelination of the central nervous system. Hypothesis/Objectives To report the long-term clinical course and the imaging characteristics of hypomyelinating leukodystrophy in German Shepherd dogs. Animals and Methods Three related litters with 11 affected dogs. Results The 11 affected dogs experienced coarse, side-to-side tremors of the head and trunk, which interfered with normal goal-oriented movements and disappeared at rest. Signs were noticed shortly after birth. Nine dogs were euthanized, 3 dogs underwent pathological examination, and 2 littermates were raised by their breeder. Tremors improved gradually until 6 to 7 months of age. Adult dogs walked with severe residual pelvic limb ataxia. One dog developed epilepsy with tonic-clonic seizures at 15 months of age. Conventional magnetic resonance imaging (MRI) disclosed homogenous hyperintense signal of the entire subcortical white matter in 3 affected 7-week-old dogs and a hypointense signal in a presumably unaffected littermate. Subcortical white matter appeared isointense to gray matter at 15 and 27 weeks of age on repeated MRI. Abnormal white matter signal with failure to display normal gray-white matter contrast persisted into adulthood. Cerebellar arbor vitae was not visible at any time point. Clinical signs, MRI findings, and pathological examinations were indicative of a hypomyelinating leukodystrophy. All parents of the affected litters shared a common ancestor and relatedness of the puppies suggested an autosomal recessive mode of inheritance. Conclusion We describe a novel hypomyelinating leukodystrophy in German Shepherd dogs with a suspected inherited origin.
  • Leeb, Tosso; Leuthard, Fabienne; Jagannathan, Vidhya; Kiener, Sarah; Letko, Anna; Roosje, Petra; Welle, Monika M.; Gailbreath, Katherine L.; Cannon, Andrea; Linek, Monika; Banovic, Frane; Olivry, Thierry; White, Stephen D.; Batcher, Kevin; Bannasch, Danika; Minor, Katie M.; Mickelson, James R.; Hytönen, Marjo K.; Lohi, Hannes; Mauldin, Elizabeth A.; Casal, Margret L. (2020)
    Cutaneous lupus erythematosus (CLE) in humans encompasses multiple subtypes that exhibit a wide array of skin lesions and, in some cases, are associated with the development of systemic lupus erythematosus (SLE). We investigated dogs with exfoliative cutaneous lupus erythematosus (ECLE), a dog-specific form of chronic CLE that is inherited as a monogenic autosomal recessive trait. A genome-wide association study (GWAS) with 14 cases and 29 controls confirmed a previously published result that the causative variant maps to chromosome 18. Autozygosity mapping refined the ECLE locus to a 493 kb critical interval. Filtering of whole genome sequence data from two cases against 654 controls revealed a single private protein-changing variant in this critical interval, UNC93B1:c.1438C>A or p.Pro480Thr. The homozygous mutant genotype was exclusively observed in 23 ECLE affected German Shorthaired Pointers and an ECLE affected Vizsla, but absent from 845 controls. UNC93B1 is a transmembrane protein located in the endoplasmic reticulum and endolysosomes, which is required for correct trafficking of several Toll-like receptors (TLRs). The p.Pro480Thr variant is predicted to affect the C-terminal tail of the UNC93B1 that has recently been shown to restrict TLR7 mediated autoimmunity via an interaction with syndecan binding protein (SDCBP). The functional knowledge on UNC93B1 strongly suggests that p.Pro480Thr is causing ECLE in dogs. These dogs therefore represent an interesting spontaneous model for human lupus erythematosus. Our results warrant further investigations of whether genetic variants affecting the C-terminus of UNC93B1 might be involved in specific subsets of CLE or SLE cases in humans and other species.
  • Reunanen, Saku (Helsingin yliopisto, 2020)
    Parkinson’s disease (PD) is a neurodegenerative disease in which dopaminergic neurons that form the nigrostriatal pathway gradually die. This causes the main motor symptoms of Parkinson’s disease: tremor, rigidity and bradykinesia. While PD affects 1-2% of total population, all currently used medicines are symptomatic, and there is no disease modifying therapy available at present. Although several different animal models for Parkinson’s disease exist, the lack of adequate animal models is often cited as a major obstacle for predicting the clinical success of potential drug candidates. Lewy bodies (LBs) are abnormal aggregates that develop and spread inside nerve cells of human PD patients, their main structural component being α-synuclein. Because α-synuclein is thought to play a major role in the pathology of PD, much research has been focused on it. Different α-synuclein-based animal models of PD exist today, of which the most recent are based on using direct injections of preformed α-synuclein fibrils (PFFs). These new α-synuclein based disease models have helped to understand the disease process in PD better, but cell death in these models takes longer to achieve and is often less pronounced compared to traditional neurotoxin based animal models of PD. The aim of this study was to participate in the development and characterization of a novel mouse model of PD. This new model combines PFF-injections with the commonly used neurotoxin 6-OHDA, which should result in more robust dopamine pathway degeneration than what is seen with the current PFF-based models. The main hypothesis of this study was that the combination of intrastriatal injections of PFFs and a low dose of 6-OHDA would cause gradual spreading of the α-synuclein aggregation pathology in the nigrostriatal dopamine pathway and progressive dopamine neuron loss leading to motor deficits. C57BL/6 mice were stereotactically injected unilaterally with both PFF and 6-OHDA, and their performance was assessed every other week with different behavioral tests until week 12. At the end, brains were collected and optical density of tyrosine hydroxylase (TH) and dopamine transporter (DAT) was measured from striatal sections, and TH and DAT positive cells in the substantia nigra were counted. The amount of Lewy bodies present in the brain slices was also counted from the cortex and substantia nigra areas of the brain. In the histological assays, statistically significant reductions of both TH and DAT were found in the brain sections of the PFF + 6-OHDA combination group and the amount of TH and DAT positive cells were lower in this group compared to the group receiving vehicle treatment only. However, the results of behavioral tests were non-significant, although a non-statistical positive trend in the amphethamine-induced rotations test was observed where mice receiving PFF + 6-OHDA rotated the most. Taken together, combination model that utilizes both PFF and 6-OHDA injections seems like a promising candidate in modelling PD in mice, but much more research and further development of the model is required before this combination model is ready and robust for use in drug development.
  • Jaatinen, Pia; Sarviharju, Maija; Raivio, Noora; Eriksson, Peter; Hervonen, Antti; Kiianmaa, Kalervo (2013)
  • Airikkala, Ilona (Helsingfors universitet, 2000)
    Uusi herpesvirusten sukuun kuuluva virus aiheutti 50 % kuolleisuuteen johtaneen epidemian 1984 hollantilaisessa merinisäkäskeskuksessa. Tämän jälkeen hylkeiden herpesvirusvasta-aineita on todettu useilta Pinnipedia-heimon lajeilta ympäri maailmaa. Pohjanmerellä kuoli tuhansittain harmaahylkeitä vuoden 1988 aikana hylkeiden morbilliviruksen aiheuttamaan sairauteen. Hylkeiden herpesvirus (Phocid herpesvirus type 1, PhHV-1) eristettiin myös kuolleiden eläinten elimistä antaen aihetta epäillä herpesviruksen osuutta näin suureen kuolleisuuteen johtaneeseen taudinkuvaan. Yleisesti herpesvirusinfektioille on tyypillistä että stressi yhdessä infektion kanssa saa aikaan rajumman sairauden. Luonnoneläinten tuominen sairaalahoitoon läheiseen kontaktiin muiden eläinten kanssa on kliinistä sairautta mahdollisesti vakavoittava stressitekijä. Hylkeiden suojaaminen kliiniseltä taudilta paikoissa, joissa hylkeitä pidetään syystä tai toisesta vankeudessa on ollut lähtökohtana rokotteen kehittämiselle. Rokotetutkimuksia varten on hylkeiden herpesviruksesta eristetty immunogeenisiä glykoproteiineja. Muilla herpesviruksilla suoritetut immunogeenisyystutkimukset ovat osoittaneet glykoproteiini B:n ja D:n olevan erityisen tehokkaita humoraalisen ja soluvälitteisen immuniteetin syntymiseen. Nämä glykoproteiinit on siksi valittu komponenteiksi rokotteeseen PhHV-1:tä vastaan. Tulevaisuuden rokotteen kliinisen tehon tutkimista varten ennen rokotteen ottamista rutiinikäyttöön merinisäkäskeskuksessa on tutkittu koe-eläinmallin sopivuutta. Oma tutkimukseni alkoi glykoproteiini D:n tuottamisella soluviljelmässä tarkoituksena tuottaa riittävästi proteiinia jotta sen immunogeenisyys voitaisiin testata. Pilottitutkimuksen omaisesti oli myös tarkoitus selvittää bakulovirusmenetelmän sopivuus juuri tämän proteiinin tuottamiseen. Tuotetusta proteiinista valmistettiin iscom-rokote, jolla immunisoitiin hiiriä. Tutkimukseni eläinmalli-osassa tutkimme kahden eri mallin sopivuutta rokotteen kliinisen tehon tutkimista varten. Heterologinen kissamalli, jossa kissat rokotettiin ensin joko PhHV-1–iscom – tai FHV-iscom rokotteella ja sitten altistettiin FHV infektiolle, osoittautui paremmaksi vaihtoehdoksi kun hiirien infektoiminen PhHV-1:llä. Kissamallin avulla voidaan tutkia rokotteen antamaa suojaa kliinistä tautia vastaan. Todettiin myös että PhHV-1 iscom-rokotus vähensi viruksen erittymistä verrattuna rokottamattomaan kontrolliryhmään. Glykoproteiini D osoittautui tässä pilottitutkimuksessa riittävän immunogeeniseksi, joten tutkimusta on syytä jatkaa. Glykoproteiini B:n kohdalla hyväksi todettu bakulovirusvektorimenetelmä ei kuitenkaan sellaisenaan sovi käytettäväksi gD:n tuottamisessa, vaan sitä on optimoitava. Rokottamisen tavoitteena ei suinkaan ole pyrkimys luonnossa elävien hylkeiden rokottamiseen vaan tavoitteena on suojata orvot poikaset vakavalta taudilta niiden ensimmäisten sairaalahoitoviikkojen ajan.
  • Salonius, Eve; Muhonen, Virpi; Lehto, Kalle; Järvinen, Elina; Pyhältö, Tuomo; Hannula, Markus; Aula, Antti S.; Uppstu, Peter; Haaparanta, Anne-Marie; Rosling, Ari; Kellomäki, Minna; Kiviranta, Ilkka (2019)
    Deep osteochondral defects may leave voids in the subchondral bone, increasing the risk of joint structure collapse. To ensure a stable foundation for the cartilage repair, bone grafts can be used for filling these defects. Poly(lactide-co-glycolide) (PLGA) is a biodegradable material that improves bone healing and supports bone matrix deposition. We compared the reparative capacity of two investigative macroporous PLGA-based biomaterials with two commercially available bone graft substitutes in the bony part of an intra-articular bone defect created in the lapine femur. New Zealand white rabbits (n = 40) were randomized into five groups. The defects, 4 mm in diameter and 8 mm deep, were filled with neat PLGA; a composite material combining PLGA and bioactive glass fibres (PLGA-BGf); commercial beta-tricalcium phosphate (beta-TCP) granules; or commercial bioactive glass (BG) granules. The fifth group was left untreated for spontaneous repair. After three months, the repair tissue was evaluated with X-ray microtomography and histology. Relative values comparing the operated knee with its contralateral control were calculated. The relative bone volume fraction ( increment BV/TV) was largest in the beta-TCP group (p
  • Kulesskaya, Natalia; Karpova, Nina N.; Ma, Li; Tian, Li; Voikar, Vootele (2014)
  • van Steenbeek, F. G.; Hytonen, M. K.; Leegwater, P. A. J.; Lohi, H. (2016)
    Since the annotation of its genome a decade ago, the dog has proven to be an excellent model for the study of inherited diseases. A large variety of spontaneous simple and complex phenotypes occur in dogs, providing physiologically relevant models to corresponding human conditions. In addition, gene discovery is facilitated in clinically less heterogeneous purebred dogs with closed population structures because smaller study cohorts and fewer markers are often sufficient to expose causal variants. Here, we review the development of genomic resources from microsatellites to whole-genome sequencing and give examples of successful findings that have followed the technological progress. The increasing amount of whole-genome sequence data warrants better functional annotation of the canine genome to more effectively utilise this unique model to understand genetic contributions in morphological, behavioural and other complex traits.
  • Lipponen, Aino (Helsingin yliopisto, 2020)
    Spinal cord injury (SCI) in human patients is the most expensive clinical condition worldwide, restricting individuals’ ability to manage with daily-life activities independently. With very limited available treatment possibilities, the understanding and validating of regenerative mechanisms and treatment options in animal models is crucial for their translation to clinical practice. The majority of SCIs in human patients are contusive in the cervical level of the spinal cord. However, thoracic injury rodent model is more commonly studied, with only recent studies working with cervical contusion injury model. Chondroitin sulphate proteoglycans (CSPGs), and especially their CS chains, are thought to be the major inhibitory structures for neurite regeneration after SCI. However, current research has led to a new idea that the inhibitory effect of CS chains can be reversed to regeneration enhancing by heparin-binding growth-associated molecule (HB-GAM). This endogenously secreted molecule is highly up-regulated in the central nervous system (CNS) during postnatal development, but in the adult CNS the expression is down-regulated. This suggests that postnatal-level concentrations might be needed for inducing neurite regeneration in adult CNS. In this study, HB-GAM treatment was tested on both cervical hemicontusion and hemisection injury models. Here we show that repeated intrathecal injections of HB-GAM were sufficient to increase grey matter myelin optical density in mouse hemicontusion injury model, and partly induce functional recovery in hemisection model. Obtained anatomical evidence suggests that enhanced myelination is potentially involved in the repair mechanism of HB-GAM. The connection between HB-GAM treatment and functional recovery, and also other mechanisms of HB-GAM-induced regeneration need further exploration. In broader perspective, the results are promising for translation of a novel treatment approach to clinical use.
  • Ignatius, Adele (Helsingin yliopisto, 2021)
    Misfolding and aggregation of alpha-synuclein (α-syn) protein, leading to dysfunctional proteins and toxic protein aggregates, are seen as major factors in the pathogenesis of Parkinson’s disease (PD). Direct protein-protein interactions (PPI) between α-syn and a serine endopeptidase, prolyl oligopeptidase (PREP), have been shown to increase α-syn aggregation. Small molecular PREP inhibitors, in turn, have been shown to reduce the ɑ-syn aggregation process both in vitro and in vivo. Inhibition of PREP has been shown to have dual effects on ɑ-syn aggregation: first of all, blocking PREP mediated seeding and secondly, inducing the clearance of ɑ-syn aggregates via increased autophagy. Thus, PREP inhibitors should be further studied as a potential treatment for PD and other synucleinopathies. In this study, we evaluated the effect of two different PREP inhibitors, 4-phenylbutanoyl-L-prolyl-2(S)-cyanopyrrolidine (KYP-2047) and HUP-115 in a virus vector-based unilateral A53T-ɑ-syn overexpression mouse model. AAV-A53T-ɑ-syn injections used in this study caused a significant increase in oligomer-specific alpha-synuclein (ɑ-synO5) immunoreactivity and a mild dopaminergic neuron loss, together with mild motor deficits. Neither 2-week PREP inhibition with KYP-2047 or 4-week PREP inhibition with HUP-115 reduced ɑ-synO5 immunoreactivity or protected dopaminergic neurons in the substantia nigra (SN). Concordant to this, the treatments did not restore the slight behavioral deficit AAV-A53T-ɑ-syn injections caused in the cylinder test. In previous studies, PREP inhibition with KYP-2047 decreased ɑ-synO5 immunoreactivity, attenuated dopaminergic neuron loss and restored behavioral deficits in other α-syn overexpression mouse models. It is suggested that PREP inhibitors mainly have an effect on soluble ɑ-syn oligomers, rather than insoluble fibrils. In case A53T-ɑ-syn forms insoluble fibrils too rapidly in mice, overexpression of A53T-ɑ-syn might not be a suitable option when studying the effects of PREP inhibitors. Our results suggest that further characterization of this model in mice is much needed before drawing any conclusions about the effect of these PREP inhibitors.
  • Saarreharju, Roosa (Helsingin yliopisto, 2020)
    While weeks of continuous treatment is required for conventional antidepressant drugs (e.g. fluoxetine) to bring their full therapeutic effects, a subanesthetic dose of ketamine alleviates the core symptoms of depression (anhedonia, depressed mood) and suicidal thinking within just few hours and the effects may last for days. Nitrous oxide (N2O, “laughing gas”), another NMDAR antagonist, has recently been shown to have similar rapid antidepressant effects in treatment-resistant depressed patients (Nagele et al. 2015). We previously found using naïve mice ketamine and N2O treatment to upregulate five mRNAs related to the MAPK pathway and synaptic plasticity, both implicated as being important in the action of rapid-acting antidepressants. In the current study, these shared mechanisms were further investigated in C57BL/6JHsd mice, using behavioral test batteries to study depressive-like behaviour and RT-qPCR for biochemical analyses. We first aimed to demonstrate behavioral differences between naïve mice and a chronic corticosterone-induced animal model of depression, and to use this model to investigate antidepressant-like effects of ketamine and N2O. According to the results, chronic corticosterone produced some behaviors typical of a depressive-like phenotype, namely significant worsening of coat state and decreased saccharin consumption in the saccharin preference test. Both ketamine and N2O exhibited antidepressant-like effects by reverting decreased saccharin preference. We then aimed to elucidate the effects of ketamine and N2O on five previously found shared mRNAs: Arc, Dusp1, Dusp5, Dusp6 and Nr4a1. N2O significantly upregulated all targets in the vmPFC, except Dusp5, two hours after beginning of N2O treatment. Neither ketamine nor sole chronic corticosterone produced any significant changes. The results of this study suggest that N2O is a potential candidate for rapid alleviation of depressive symptoms. We suggest that the action of rapid-acting antidepressants, more specifically N2O, is based on a homeostatic response of the brain to a presented challenge. Here this challenge would be cortical excitation previously been shown to be caused by N2O, which leads to activation of pathways such as MAPK and subsequent Arc, Dusp and Nr4a1 signaling. The level of expression of these markers would then depend on which phase this response is in and hence, the differences in time between treatment and brain sample dissection could be a reason for conflicting results to previous research. Future studies would benefit from detailed investigation of the chronic corticosterone-induced model due to its potential in controlling for behavioral variability, thus reducing the number of animals needed for preclinical research. Overall the preliminary findings of this study could be one of the first steps in the search for the mechanisms underlying the potential antidepressant effect of N2O, how these molecular markers are related to its action and how it differs from the action of ketamine.
  • Comandolli-Wyrepkowski, Claudia Dantas; Grafova, Iryna; Naiff, Maricleide de Farias; Avella, Maurizio; Gentile, Gennaro; Grafov, Andriy; Ramos Franco, Antonia Maria (2017)
    Current treatment of cutaneous leishmaniasis (CL) relies mainly on pentavalent antimonials salts and second-line drugs include pentamidine and amphotericin B, but these therapies have side effects and require parenteral administration. The aim of this work was to evaluate the topical formulations containing pentamidine isethionate (PI) in the experimental treatment of cutaneous leishmaniasis (CL). Golden hamsters (Mesocricetus auratus) were infected in the nose with Leishmania (Leishmania) amazonensis. Six treatment groups received different topical treatments of anhydrous or hydrating emulsions, for a maximum of 10 days, with an application of 50 mg day(-1). After treatment tissue samples of lesions were evaluated by histology, transmission electron microscopy and biopsy cultivation. Compared with untreated group, topical treatment with hydrating emulsion with 10% PI and usnic acid (ACE5AU) showed significantly decrease in volume lesion (P= 0.028) on 20th day after the end of the treatment with reduction of 27.37%. Topical treatment with anhydrous emulsion with 10% PI and usnic acid (ACPU) reduces parasite burden in Golden hamsters. This study demonstrated the potential of topical treatment to reduce the number of parasites that could be combined with others drugs and to have a faster and more effective treatment of cutaneous leishmaniasis.
  • Ahola, Sari (Helsingfors universitet, 2015)