| 1. |
- Hodik, Monika, et al.
(author)
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Coxsackie-adenovirus receptor expression is enhanced in pancreas from patients with type 1 diabetes
- 2016
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In: BMJ Open Diabetes Research & Care. - : BMJ. - 2052-4897. ; 4:1
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Journal article (peer-reviewed)abstract
- Objectives: One of the theories connecting enterovirus (EV) infection of human islets with type 1 diabetes (T1D) is the development of a fertile field in the islets. This implies induction of appropriate proteins for the viral replication such as the coxsackie-adenovirus receptor (CAR). The aim of this study was to investigate to what extent CAR is expressed in human islets of Langerhans, and what conditions that would change the expression.Design: Immunohistochemistry for CAR was performed on paraffin-embedded pancreatic tissue from patients with T1D (n=9 recent onset T1D, n=4 long-standing T1D), islet autoantibody-positive individuals (n=14) and non-diabetic controls (n=24) individuals. The expression of CAR was also examined by reverse transcription PCR on microdissected islets (n=5), exocrine tissue (n=5) and on explanted islets infected with EV or exposed to chemokines produced by EV-infected islet cells.Results: An increased frequency of patients with T1D and autoantibody-positive individuals expressed CAR in the pancreas (p<0.039). CAR staining was detected more frequently in pancreatic islets from patients with T1D and autoantibody-positive subjects (15/27) compared with (6/24) non-diabetic controls (p<0.033). Also in explanted islets cultured in UV-treated culture medium from coxsackievirus B (CBV)-1-infected islets, the expression of the CAR gene was increased compared with controls. Laser microdissection of pancreatic tissue revealed that CAR expression was 10-fold higher in endocrine compared with exocrine cells of the pancreas. CAR was also expressed in explanted islets and the expression level decreased with time in culture. CBV-1 infection of explanted islets clearly decreased the expression of CAR (p<0.05). In contrast, infection with echovirus 6 did not affect the expression of CAR.Conclusions: CAR is expressed in pancreatic islets of patients with T1D and the expression level of CAR is increased in explanted islets exposed to proinflammatory cytokines/chemokines produced by infected islets. T1D is associated with increased levels of certain chemokines/cytokines in the islets and this might be the mechanism behind the increased expression of CAR in TID islets.
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| 2. |
- Hodik, Monika
(author)
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Enterovirus Implications in Type 1 Diabetes
- 2013
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Doctoral thesis (other academic/artistic)abstract
- Human enteroviruses (HEVs), particularly Coxsackie B viruses (CVBs), might trigger the onset of type 1 diabetes (T1D), either by direct infection of the insulin-producing beta-cells or by an indirect inflammatory response. The overall aim of this thesis was to study the tropism of HEVs in isolated human pancreatic cell clusters in vitro including virus effects on islet function, gene-expression and ultrastructure. Furthermore, the expression of the major CVB-receptor, CAR, was investigated in pancreatic tissue from T1D-related subjects and CVB-infected islets. Also, tissues and isolated islets from two adult organ-donors who died close to disease onset were studied.The results showed that beta-cells were destroyed through lytic infections with different strains of CVBs and that islets function did not depend on replication per se but on the degree of islet destruction. Virus particles were observed in beta-cells in association with insulin granules, however no virus replication or particles could be observed in the exocrine cell clusters, as opposed to in mice models. The virus-infected islets had a decreased expression of insulin mRNA and CAR mRNA/protein, possibly reflecting virus-killed beta-cells. Infected beta-cells contained a high number of insulin granules, which might indicate an impaired function.The in vivo studies showed presence of virus proteins in the islets of both donors who died close to onset of T1D and elevated expression of innate immunity genes, potentially indicating viral infection, but direct evidence is lacking. Both donors were immune-reactive for insulin but the isolated islets had an impaired or completely lacking glucose response. Ultrastructural analysis showed both damaged beta-cells and normal-looking beta-cells, indicating that the latter might still have the potential to function but were blocked. CAR-expression was significantly increased in T1D-related subjects which might indicate tissue damage and/or inflammation in these subjects.To conclude, these results showed that CVBs could infect human primary beta-cells, likely by binding to CAR and lead to functional abnormalities, indicating that they could cause T1D in vivo. Exocrine cells were not permissive to CVB, which raises the question if mice-models should be used to study human pancreatitis. Also, unique materials from two T1D organ-donors were described.
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| 3. |
- Hodik, Monika, et al.
(author)
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Enterovirus infection of human islets of Langerhans affects beta-cell function resulting in disintegrated islets, decreased glucose stimulated insulin secretion and loss of Golgi structure
- 2016
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In: BMJ OPEN DIABETES RESEARCH & CARE. - : BMJ. - 2052-4897. ; 4:1
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Journal article (peer-reviewed)abstract
- Aims/hypothesis: In type 1 diabetes (T1D), most insulin-producing beta cells are destroyed, but the trigger is unknown. One of the possible triggers is a virus infection and the aim of this study was to test if enterovirus infection affects glucose stimulated insulin secretion and the effect of virus replication on cellular macromolecules and organelles involved in insulin secretion. Methods: Isolated human islets were infected with different strains of coxsackievirus B (CVB) virus and the glucose-stimulated insulin release (GSIS) was measured in a dynamic perifusion system. Classical morphological electron microscopy, large-scale electron microscopy, so-called nanotomy, and immunohistochemistry were used to study to what extent virus-infected beta cells contained insulin, and real-time PCR was used to analyze virus induced changes of islet specific genes. Results: In islets infected with CVB, GSIS was reduced in correlation with the degree of virus-induced islet disintegration. The expression of the gene encoding insulin was decreased in infected islets, whereas the expression of glucagon was not affected. Also, in islets that were somewhat disintegrated, there were uninfected beta cells. Ultrastructural analysis revealed that virus particles and virus replication complexes were only present in beta cells. There was a significant number of insulin granules remaining in the virus-infected beta cells, despite decreased expression of insulin mRNA. In addition, no typical Golgi apparatus was detected in these cells. Exposure of islets to synthetic dsRNA potentiated glucose-stimulated insulin secretion. Conclusions/interpretation: Glucose-stimulated insulin secretion; organelles involved in insulin secretion and gene expression were all affected by CVB replication in beta cells.
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| 4. |
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| 5. |
- Hodik, Monika, et al.
(author)
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Tropism Analysis of Two Coxsackie B5 Strains Reveals Virus Growth in Human Primary Pancreatic Islets but not in Exocrine Cell Clusters In Vitro
- 2013
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In: Open Virology Journal. - : Bentham Science Publishers Ltd.. - 1874-3579. ; 7, s. 49-56
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Journal article (peer-reviewed)abstract
- Human Enteroviruses (HEVs) have been implicated in human pancreatic diseases such as pancreatitis and type 1 diabetes (T1D). Human studies are sparse or inconclusive and our aim was to investigate the tropism of two strains of Coxsackie B virus 5 (CBV-5) in vitro to primary human pancreatic cells. Virus replication was measured with TCID50 titrations of aliquots of the culture medium at different time points post inoculation. The presence of virus particles or virus proteins within the pancreatic cells was studied with immunohistochemistry (IHC) and electron microscopy (EM). None of the strains replicated in the human exocrine cell clusters, in contrast, both strains replicated in the endocrine islets of Langerhans. Virus particles were found exclusively in the endocrine cells, often in close association with insulin granules. In conclusion, CBV-5 can replicate in human endocrine cells but not in human exocrine cells, thus they might not be the cause of pancreatitis in humans. The association of virus with insulin granules might reflect the use of these as replication scaffolds.
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| 6. |
- Latini, Francesco, M.D. 1982-, et al.
(author)
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The link between gliomas infiltration and white matter architecture investigated with electron microscopy and diffusion tensor imaging
- 2021
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In: NeuroImage. - : Elsevier. - 2213-1582. ; 31, s. 102735-
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Journal article (peer-reviewed)abstract
- Diffuse low-grade gliomas display preferential locations in eloquent and secondary associative brain areas. The reason for this tendency is still unknown. We hypothesized that the intrinsic architecture and water diffusion properties of the white matter bundles in these regions may facilitate gliomas infiltration. Magnetic resonance imaging of one hundred and two low-grade gliomas patients were normalized to/and segmented in MNI space to create a probabilistic infiltration weighted gradient map. Diffusion tensor imaging (DTI)- based parameters were derived for five major white matter bundles, displaying high- and low grade of infiltration, (corpus callosum, cingulum, arcuate fasciculus, inferior fronto-occipital fasciculus and cortico-spinal tract), averaged over 20 healthy individuals acquired from the Human connectome project (HCP) database. Transmission electron microscopy (TEM) was used to analyze fiber density, diameter and g-ratio in 100 human white matter regions, sampled from cadaver specimens, reflecting areas with different gliomas infiltration frequency. Histological results and DTI-based parameters were compared in anatomical regions of high- and low grade of infiltration respectively. We detected differences in the infiltration frequency of five major white matter bundles. Regional differences within the same white matter bundles were detected by both TEM- and DTI analysis. Regions with high infiltration frequency (HIF) displayed a higher fiber density, smaller fiber diameter but higher myelin thickness and lower axial diffusivity compare compared with low infiltration frequency (LIF) regions. Our results seem to indicate that the fiber diameter, myelin thickness and the possible organization of the fibers are different in HIF compared to LIF regions and may be linked to the preferential location of diffuse low-grade gliomas.
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| 7. |
- Li, Hao, et al.
(author)
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Regeneration in the Auditory Organ in Cuban and African Dwarf Crocodiles (Crocodylus rhombifer and Osteolaemus tetraspis) Can We Learn From the Crocodile How to Restore Our Hearing?
- 2022
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In: Frontiers in Cell and Developmental Biology. - : Frontiers Media S.A.. - 2296-634X. ; 10
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Journal article (peer-reviewed)abstract
- Background: In several non-mammalian species, auditory receptors undergo cell renewal after damage. This has raised hope of finding new options to treat human sensorineural deafness. Uncertainty remains as to the triggering mechanisms and whether hair cells are regenerated even under normal conditions. In the present investigation, we explored the auditory organ in the crocodile to validate possible ongoing natural hair cell regeneration. Materials and Methods: Two male Cuban crocodiles (Crocodylus rhombifer) and an adult male African Dwarf crocodile (Osteolaemus tetraspis) were analyzed using transmission electron microscopy and immunohistochemistry using confocal microscopy. The crocodile ears were fixed in formaldehyde and glutaraldehyde and underwent micro-computed tomography (micro-CT) and 3D reconstruction. The temporal bones were drilled out and decalcified. Results: The crocodile papilla basilaris contained tall (inner) and short (outer) hair cells surrounded by a mosaic of tightly connected supporting cells coupled with gap junctions. Afferent neurons with and without ribbon synapses innervated both hair cell types. Supporting cells occasionally showed signs of trans-differentiation into hair cells. They expressed the MAFA and SOX2 transcription factors. Supporting cells contained organelles that may transfer genetic information between cells, including the efferent nerve fibers during the regeneration process. The tectorial membrane showed signs of being replenished and its architecture being sculpted by extracellular exosome-like proteolysis. Discussion: Crocodilians seem to produce new hair cells during their life span from a range of supporting cells. Imposing efferent nerve fibers may play a role in regeneration and re-innervation of the auditory receptors, possibly triggered by apoptotic signals from wasted hair cells. Intercellular signaling may be accomplished by elaborate gap junction and organelle systems, including neural emperipolesis. Crocodilians seem to restore and sculpt their tectorial membranes throughout their lives.
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| 8. |
- Li, Hao, 1984-, et al.
(author)
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The ultrastructure of a stria vascularis in the auditory organ of the cuban crocodile (Crocodylus rhombifer)
- 2023
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In: Frontiers in Cell and Developmental Biology. - : Frontiers Media S.A.. - 2296-634X. ; 11
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Journal article (peer-reviewed)abstract
- Background: An endocochlear potential (EP) exists in the mammalian cochlea generated by the stria vascularis and an associated fibrocyte network. It plays an essential role for sensory cell function and hearing sensitivity. In non-mammalian ectothermic animals the endocochlear potential is low and its origin somewhat unclear. In this study, we explored the crocodilian auditory organ and describe the fine structure of a stria vascularis epithelium that has not been verified in birds.Material and Methods: Three Cuban crocodiles (Crocodylus rhombifer) were analyzed with light and transmission electron microscopy. The ears were fixed in glutaraldehyde The temporal bones were drilled out and decalcified. The ears were dehydrated, and embedded and was followed by semi-thin and thin sectioning.Results: The fine structure of the crocodile auditory organ including the papilla basilaris and endolymph system was outlined. The upper roof of the endolymph compartment was specialized into a Reissner membrane and tegmentum vasculosum. At the lateral limbus an organized, multilayered, vascularized epithelium or stria vascularis was identified.Discussion: Electron microscopy demonstrates that the auditory organ in Crocodylus rhombifer, unlike in birds, contains a stria vascularis epithelium separate from the tegmentum vasculosum. It is believed to secrete endolymph and to generate a low grade endocochlear potential. It may regulate endolymph composition and optimize hearing sensitivity alongside the tegmentum vasculosum. It could represent a parallel evolution essential for the adaptation of crocodiles to their diverse habitats.
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| 9. |
- Libard, Sylwia, et al.
(author)
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The Compartmentalization of Amyloid-β in Idiopathic Normal Pressure Hydrocephalus Brain Biopsies
- 2024
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In: Journal of Alzheimer's Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 99:2, s. 729-737
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Journal article (peer-reviewed)abstract
- Background: Amyloid-beta (A beta) is one of the hallmark lesions of Alzheimer's disease (AD). During the disease process, A beta undergoes biochemical changes, producing toxic beta variants, proposed to be detected within the neurons. Idiopathic normal pressure hydrocephalus (iNPH) causes cognitive impairment, gait, and urinary symptoms in elderly, that can be reversed by a ventriculo-peritoneal shunt. Majority of iNPH subjects display different A beta variants in their brain biopsies, obtained during shunting. Objective: To study the cellular compartmentalization of different A beta variants in brain biopsies from iNPH subjects. Methods: We studied the cellular localization of different proteoforms of A beta using antibodies towards different amino acid sequences or post-translational modifications of A beta, including clones 4G8, 6F/3D, unmodified- (7H3D6), pyroglutamylated-(N3pE), phosphorylated-(1E4E11) A beta and A beta protein precursor (A beta PP), in brain biopsies from 3 iNPH subjects, using immunohistochemistry and light microscopy (LM), light microscopy on semi-thin sections (LMst), and electron microscopy (EM). Results: In LM all A beta variants were detected. In LMst and EM, the A beta 4G8, 6F/3D, and the pyroglutamylated A beta were detected. The A beta PP was visualized by all methods. The A beta labelling was located extracellularly with no specific signal within the intracellular compartment, whereas the A beta PP was seen both intra- and extracellularly. Conclusions: TheA beta markers displayed extracellular localization when visualized by three assessment techniques, reflecting the pathological extracellular accumulation of A beta in the human brain. No intracellular A beta pathology was seen. A beta PP was visualized in intra- and extracellularly, which corresponds to the localization of the protein in the membranes of cells and organelles.
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| 10. |
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