Time filter

Source Type

Reykjavík, Iceland

Olafsson I.H.,University of Iceland | Vilhjalmsson D.T.,Skane University Hospital | Thormodsson F.R.,ValaMed ehf
Methods in Molecular Biology | Year: 2012

Cerebral amyloid angiopathy (CAA) results from amyloid accumulation within arteries of the cerebral cortex and leptomeninges. This condition is age-related, especially prevalent in Alzheimer's disease (AD), and the main feature of certain hereditary disorders (i.e., HCHWA-I). The vascular smooth muscle cells (VSMCs) appear to play a vital role in the development of CAA, which makes them well suited as an experimental model to study the disease and screen for possible remedies. We describe two different methods for isolating and culturing human VSMCs. First, using the human umbilical cord as an easy source of robust cells, and secondly, using brain tissue that provides the proper cerebral VSMCs, but is more problematic to work with. The umbilical cord also provides human umbilical vascular endothelial cells (HUVECs), useful primary cells for vascular research. Finally, the maintenance, preservation, and characterization of the isolated vascular cells are described. © 2012 Springer Science+Business Media, LLC.

Einarsson J.M.,Genis Ehf | Bahrke S.,University of Potsdam | Sigurdsson B.T.,University of Iceland | Ng C.-H.,Genis Ehf | And 7 more authors.
Biochemical and Biophysical Research Communications | Year: 2013

Recent evidences indicating that cellular kinase signaling cascades are triggered by oligomers of N-acetylglucosamine (ChOS) and that condrocytes of human osteoarthritic cartilage secrete the inflammation associated chitolectin YKL-40, prompted us to study the binding affinity of partially acetylated ChOS to YKL-40 and their effect on primary chondrocytes in culture. Extensive chitinase digestion and filtration of partially deacetylated chitin yielded a mixture of ChOS (Oligomin™) and further ultrafiltration produced T-ChOS™, with substantially smaller fraction of the smallest sugars. YKL-40 binding affinity was determined for the different sized homologues, revealing micromolar affinities of the larger homologues to YKL-40. The response of osteoarthritic chondrocytes to Oligomin™ and T-ChOS™ was determined, revealing 2- to 3-fold increases in cell number. About 500. μg/ml was needed for Oligomin™ and around five times lower concentration for T-ChOS™, higher concentrations abolished this effect for both products. Addition of chitotriose inhibited cellular responses mediated by larger oligosaccharides. These results, and the fact that the partially acetylated T-ChOS™ homologues should resist hydrolysis, point towards a new therapeutic concept for treating inflammatory joint diseases. © 2013 Elsevier Inc.

Vilhjalmsson D.T.,Skane University Hospital | Ingolfsdottir I.E.,University of Iceland | Thormodsson F.R.,ValaMed ehf
Methods in Molecular Biology | Year: 2012

Amyloid fibrils are highly insoluble in neutral aqueous media of regular ionic strengths making solubilization a difficult task that normally calls for extremely harsh treatment. This is among the reasons for the routine employment of synthetic proteins in amyloid research, where the amylogenic components are needed. Here we describe a process for solubilizing amyloid in pure water that we adopted from a method developed by Mordechai Pras and associates. We have used it for solubilizing cystatin C amyloid and extracting it out of leptomeningeal tissue and skin from Hereditary Cerebral Hemorrhage with Amyloidosis-Icelandic type (HCHWA-I) patients. HCHWA-I is a rare and very aggressive heritable form of cerebral amyloid angiopathy (CAA)-specific Icelandic type. Similar approach has been employed for solubilization of different forms of amyloid from other organs suggesting broad range of applicability. © 2012 Springer Science+Business Media, LLC.

Jonsdottir G.,University of Iceland | Ingolfsdottir I.E.,University of Iceland | Thormodsson F.R.,University of Iceland | Thormodsson F.R.,ValaMed ehf | Petersen P.H.,University of Iceland
Neurobiology of Aging | Year: 2013

A mutation in the human cystatin C gene leads to familial cerebral amyloid angiopathy. This disease is known as " hereditary cerebral hemorrhage with amyloidosis-Icelandic type" or " hereditary cystatin C amyloid angiopathy." The mutant cystatin C protein forms aggregates and amyloid, within the central nervous system almost exclusively in connection with the vascular system. It was not known whether immune cells could remove mutant cystatin C protein aggregates. Ex vivo mutant cystatin C protein aggregates, both in solution and dried onto a glass surface, induced adhesion to the substrate, differentiated the THP-1 monocyte cell line and led to a proinflammatory response. Aggregates were also taken up by both THP-1 cells and THP-1 derived macrophages. These are the same responses induced by other amyloidogenic protein species, such as amyloid β protein and amylin, supporting the model of all amyloidogenic proteins being toxic due to common structural motifs. Proinflammatory response induced by the ex vivo mutant cystatin C protein aggregates suggests that vascular inflammation plays an important role in hereditary cerebral hemorrhage with amyloidosis-Icelandic type. Ex vivo protein aggregates of cystatin C might better model cellular behavior than in vitro-generated aggregates or supplement in vitro material. © 2013 Elsevier Inc.

Discover hidden collaborations