| 1. |
- Delsing, Louise, et al.
(author)
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Barrier properties and transcriptome expression in human iPSC-derived models of the blood-brain barrier
- 2018
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In: Stem Cells. - : AlphaMed Press, Inc.. - 1066-5099 .- 1549-4918. ; 36:12, s. 1816-1827
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Journal article (peer-reviewed)abstract
- Cell-based models of the blood-brain barrier (BBB) are important for increasing the knowledge of BBB formation, degradation and brain exposure of drug substances. Human models are preferred over animal models because of inter-species differences in BBB structure and function. However, access to human primary BBB tissue is limited and has shown degeneration of BBB functions in vitro. Human induced pluripotent stem cells (iPSCs) can be used to generate relevant cell types to model the BBB with human tissue. We generated a human iPSC-derived model of the BBB that includes endothelial cells in co-culture with pericytes, astrocytes and neurons. Evaluation of barrier properties showed that the endothelial cells in our co-culture model have high transendothelial electrical resistance, functional efflux and ability to discriminate between CNS permeable and non-permeable substances. Whole genome expression profiling revealed transcriptional changes that occur in co-culture, including upregulation of tight junction proteins such as claudins and neurotransmitter transporters. Pathway analysis implicated changes in the WNT, TNF and PI3K-Akt pathways upon co-culture. Our data suggests that co-culture of iPSC-derived endothelial cells promotes barrier formation on a functional and transcriptional level. The information about gene expression changes in co-culture can be used to further improve iPSC-derived BBB models through selective pathway manipulation.
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| 2. |
- Delsing, Louise, et al.
(author)
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Enhanced xeno-free differentiation of hiPSC-derived astroglia applied in a blood-brain barrier model
- 2019
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In: Fluids and Barriers of the Cns. - : Springer Science and Business Media LLC. - 2045-8118. ; 16:1
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Journal article (peer-reviewed)abstract
- Background Human induced pluripotent stem cells (hiPSC) hold great promise for use in cell therapy applications and for improved in vitro models of human disease. So far, most hiPSC differentiation protocols to astroglia use undefined, animal-containing culture matrices. Laminins, which play an essential role in the regulation of cell behavior, offer a source of defined, animal-free culture matrix. Methods In order to understand how laminins affect astroglia differentiation, recombinant human laminin-521 (LN521), was compared to a murine Engelbreth-Holm-Swarm sarcoma derived laminin (L2020). Astroglia expression of protein and mRNA together with glutamate uptake and protein secretion function, were evaluated. Finally, these astroglia were evaluated in a coculture model of the blood-brain barrier (BBB). Results Astroglia of good quality were generated from hiPSC on both LN521 and L2020. However, astroglia differentiated on human LN521 showed higher expression of several astroglia specific mRNAs and proteins such as GFAP, S100B, Angiopoietin-1, and EAAT1, compared to astroglia differentiated on murine L2020. In addition, glutamate uptake and ability to induce expression of junction proteins in endothelial cells were affected by the culture matrix for differentiation. Conclusion Our results suggest that astroglia differentiated on LN521 display an improved phenotype and are suitable for coculture in a hiPSC-derived BBB model. This provides a starting point for a more defined and robust derivation of astroglia for use in BBB coculture models.
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| 3. |
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| 4. |
- Delsing, Louise, et al.
(author)
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Models of the blood-brain barrier using iPSC-derived cells
- 2020
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In: Molecular and Cellular Neuroscience. - : Elsevier BV. - 1044-7431 .- 1095-9327. ; 107
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Journal article (peer-reviewed)abstract
- The blood-brain barrier (BBB) constitutes the interface between the blood and the brain tissue. Its primary function is to maintain the tightly controlled microenvironment of the brain. Models of the BBB are useful for studying the development and maintenance of the BBB as well as diseases affecting it. Furthermore, BBB models are important tools in drug development and support the evaluation of the brain-penetrating properties of novel drug molecules. Currently used in vitro models of the BBB include immortalized brain endothelial cell lines and primary brain endothelial cells of human and animal origin. Unfortunately, many cell lines and primary cells do not recreate physiological restriction of transport in vitro. Human-induced pluripotent stem cell (iPSC)-derived brain endothelial cells have proven a promising alternative source of brain endothelial-like cells that replicate tight cell layers with low paracellular permeability. Given the possibility to generate large amounts of human iPSC-derived brain endothelial cells they are a feasible alternative when modelling the BBB in vitro. iPSC-derived brain endothelial cells form tight cell layers in vitro and their barrier properties can be enhanced through co-culture with other cell types of the BBB. Currently, many different models of the BBB using iPSC-derived cells are under evaluation to study BBB formation, maintenance, disruption, drug transport and diseases affecting the BBB. This review summarizes important functions of the BBB and current efforts to create iPSC-derived BBB models in both static and dynamic conditions. In addition, it highlights key model requirements and remaining challenges for human iPSC-derived BBB models in vitro.
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| 5. |
- Enquist, Henrik, et al.
(author)
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Large acoustic transients induced by non-thermal melting of InSb
- 2007
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In: Physical Review Letters. - 1079-7114. ; 98
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Journal article (peer-reviewed)abstract
- We have observed large-amplitude strain waves following a rapid change in density of InSb due to nonthermal melting. The strain has been measured in real time via time-resolved x-ray diffraction, with a temporal resolution better than 2 ps. The change from the solid to liquid density of the surface layer launches a high-amplitude strain wave into the crystalline material below. This induces an effective plane rotation in the asymmetrically cut crystal leading to deflection of the diffracted beam. The uniform strain in the layer below the molten layer is 2.0(±0.2)%. A strain of this magnitude develops within 5 ps of the incident pulse showing that the liquid has reached the equilibrium density within this time frame. Both the strain amplitude and the depth of the strained material in the solid can be explained by assuming a reduction in the speed of sound in the nonequilibrium liquid compared to measured equilibrium values.
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| 6. |
- Lind, Leili, et al.
(author)
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Preliminary results of a telemonitoring study: COPD and heart failure patients exhibit great difference in their need of health care
- 2015
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In: European Respiratory Journal. - : European Respiratory Society. ; , s. PA2790-PA2790
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Conference paper (other academic/artistic)abstract
- Background: Growing populations of elderly patients with advanced stages of COPD or heart failure (HF) urge the need for specialized health care in the patients' home. A telemonitoring study has been initiated including patients using digital pens. Health care was provided by the specialized home care unit at a university hospital. Through an IT system the staff checked all daily patient reports. We hypothesized that the two groups of patients, advanced COPD or HF, would exhibit differences regarding exacerbations and the need of health care.Objective: To study exacerbations of COPD or HF, and patient health care consumption.Methods: A tele-monitoring system, the Health diary, which is based on digital pen technology, was employed. Exacerbations were identified using information provided through the telemonitoring system. Consumed health care was assessed as the number of patient contacts (home visits or telephone consultations).Results: Presently, 33 patients with advanced disease are enrolled (13 COPD and 20 HF patients) of which 11 patients (6 COPD and 5 HF patients) have completed the 1-yr study period or have died during the study period (2 COPD and 4 HF patients). Exacerbations were 2.8 and 0.8 and patient contacts were 96 and 42 per COPD and HF patient, respectively. While HF patients were significantly older than COPD patients, the two groups demonstrated no difference regarding gender distribution and comorbidity.Conclusions: COPD patients exhibit exacerbations more frequently and demand much more home health care than patients with HF do. It seems that this difference of health care consumption is mainly due to disease characteristics.
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| 7. |
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| 8. |
- Lundin, Anders, et al.
(author)
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Human iPS-Derived Astroglia from a Stable Neural Precursor State Show Improved Functionality Compared with Conventional Astrocytic Models
- 2018
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In: Stem Cell Reports. - : Cell Press. - 2213-6711. ; 10:3, s. 1030-1045
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Journal article (peer-reviewed)abstract
- In vivo studies of human brain cellular function face challenging ethical and practical difficulties. Animal models are typically used but display distinct cellular differences. One specific example is astrocytes, recently recognized for contribution to neurological diseases and a link to the genetic risk factor apolipoprotein E (APOE). Current astrocytic in vitro models are questioned for lack of biological characterization. Here, we report human induced pluripotent stem cell (hiPSC)-derived astroglia (NES-Astro) developed under defined conditions through long-term neuroepithelial-like stem (ltNES) cells. We characterized NES-Astro and astrocytic models from primary sources, astrocytoma (CCF-STTG1), and hiPSCs through transcriptomics, proteomics, glutamate uptake, inflammatory competence, calcium signaling response, and APOE secretion. Finally, we assess modulation of astrocyte biology using APOE-annotated compounds, confirming hits of the cholesterol biosynthesis pathway in adult and hiPSC-derived astrocytes. Our data show large diversity among astrocytic models and emphasize a cellular context when studying astrocyte biology.
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| 9. |
- Skillbäck, Tobias, et al.
(author)
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CSF/serum albumin ratio in dementias : a cross-sectional study on 1861 patients
- 2017
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In: Neurobiology of Aging. - : Elsevier. - 0197-4580 .- 1558-1497. ; 59, s. 1-9
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Journal article (peer-reviewed)abstract
- A connection between dementias and blood-brain barrier (BBB) dysfunction has been suggested, but previous studies have yielded conflicting results. We examined cerebrospinal fluid (CSF)/serum albumin ratio in a large cohort of patients diagnosed with Alzheimer's disease (AD, early onset [EAD, n = 130], late onset AD [LAD, n = 666]), vascular dementia (VaD, n = 255), mixed AD and VaD (MIX, n = 362), Lewy body dementia (DLB, n = 50), frontotemporal dementia (FTD, n = 56), Parkinson's disease dementia (PDD, n = 23), other dementias (other, n = 48), and dementia not otherwise specified (NOS, n = 271). We compared CSF/serum albumin ratio to 2 healthy control groups (n = 292, n = 20), between dementia diagnoses, and tested biomarker associations. Patients in DLB, LAD, VaD, MIX, other, and NOS groups had higher CSF/serum albumin ratio than controls. CSF/serum albumin ratio correlated with CSF neurofilament light in LAD, MIX, VaD, and other groups but not with AD biomarkers. Our data show that BBB leakage is common in dementias. The lack of association between CSF/serum albumin ratio and AD biomarkers suggests that BBB dysfunction is not inherent to AD but might represent concomitant cerebrovascular pathology.
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| 10. |
- Sondhauss, Peter, et al.
(author)
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Metal-like heat conduction in laser-excited InSb probed by picosecond time-resolved x-ray diffraction
- 2008
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In: Physical Review B (Condensed Matter and Materials Physics). - : American Physical Society. - 1098-0121. ; 78:11
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Journal article (peer-reviewed)abstract
- A semiconductor (InSb) showed transient metal- like heat conduction after excitation of a dense electron- hole plasma via short and intense light pulses. A related ultrafast strain relaxation was detected using picosecond time-resolved x-ray diffraction. The deduced heat conduction was, by a factor of 30, larger than the lattice contribution. The anomalously high heat conduction can be explained once the contribution from the degenerate photocarrier plasma is taken into account. The magnitude of the effect could provide the means for guiding heat in semiconductor nanostructures. In the course of this work, a quantitative model for the carrier dynamics in laser-irradiated semiconductors has been developed, which does not rely on any adjustable parameters or ad hoc assumptions. The model includes various light absorption processes (interband, free carrier, two photon, and dynamical Burstein- Moss shifts), ambipolar diffusion, energy transport (heat and chemical potential), electrothermal effects, Auger recombination, collisional excitation, and scattering (elastic and inelastic). The model accounts for arbitrary degrees of degeneracy.
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