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- Al-Hawasi, Abbas, 1976-
(författare)
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Retinal ganglion cell examination with Optical Coherence Tomography reflects physiological and pathological changes in the eye and the brain.
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The retinal ganglion cell is situated in the inner retina and its axons, composing the retinal nerve fiber layer (RNFL), leave the eye to form the optic nerve. These cells develop embryologically from the forebrain and later during development re-establish connections with different parts of the brain serving different purposes. This unique position and connections make it possible to be investigated with different methods. Optical Coherence Tomography (OCT) is an accessible and easily operated clinical device that can provide a detailed image of this layer at a few micrometers level of precision in measurements. In this thesis we aimed to see whether examining these cells with OCT could reflect physiological and pathological changes in the eye and brain.In cases of optic neuritis (Paper I), the OCT examination showed early thickening of the peripapillary (pRNFL) followed by thinning which takes 6-9 months to reduce to below normal thickness without the ability to distinguish between the real from pseudo thinning. The ganglion cell -inner plexiform layer (GCL-IPL) layer, however, showed a thickness reduction within a few weeks to 3 months without pseudo thinning. In cases of Idiopathic Intracranial Hypertension (IIH) (Paper II), the GCL-IPL remained unchanged and there was no difference in pRNFL thickness compared to healthy controls, whereas the optic disc parameters of rim thickness, rim area, cup volume and cup/disc ratio differed significantly (P<0.05).In cases of benign multiple sclerosis (Paper IV), the OCT could detect that eyes which are not affected by optic neuritis had an annual thinning rate of the RNFL and GCL-IPL similar to a healthy population (P>0.05) which may indicate the benign course of the disease. In cases of physiological factors affecting the GCL in healthy population (Paper III) the OCT examination showed that there was a significant thinning rate of the layer with age (P<0.05), but the thinning was not significant when sex and axial length of the eye were taken into consideration. Males had a thicker GCL volume than females and with age a significant reduction in GCL volume was noted in females but not in males. A Longer axial length of the eye found to be associated with thinner GCL volume. In conclusion retinal ganglion cell changes detected with OCT can reflect physiological and pathological changes in the eye and brain.
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| 2. |
- Al-Hawasi, Abbas, et al.
(författare)
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Longitudinal Optical Coherence Tomography Measurement of Retinal Ganglion Cell and Nerve Fiber Layer to Assess Benign Course in Multiple Sclerosis
- 2023
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Ingår i: Journal of Clinical Medicine. - : MDPI. - 2077-0383. ; 12:6
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Tidskriftsartikel (refereegranskat)abstract
- A benign form of multiple sclerosis (BMS) is not easily diagnosed, but changes of the retinal ganglion cell layer-inner plexiform layer (GCL-IPL) and retinal nerve fiber layer (RNFL) may be sensitive to the disease. The aim of this study was to use optical coherence tomography (OCT) to investigate longitudinal changes of GCL-IPL and RNFL in BMS. Eighteen patients with BMS and 22 healthy control (HC) subjects were included, with a mean follow-up period of 32.1 months in BMS and 34.3 months in HC. Mean disease duration in BMS was 23.3 years, with 14 patients left untreated. Unilateral optic neuritis (ON) was found in eight patients. Non-ON eyes showed thinner GCL-IPL layer in the BMS group relative to HC (p < 0.001). The thinning rate of GCL-IPL in non-ON BMS, however, was -0.19 +/- 0.15 mu m/year vs. 0 +/- 0.11 mu m/year for HC (p = 0.573, age-adjusted). Thinning rate of RNFL in non-ON BMS was -0.2 +/- 0.27 mu m/year vs. -0.05 +/- 0.3 mu m/year for HC (p = 0.454, age adjusted). Conclusions: Thinning rate of the GCL-IPL and RNFL in BMS is similar to the healthy population but differs from the thinning rate in relapsing-remitting MS, presenting a non-invasive OCT-based criterion for assessing a benign course in multiple sclerosis.
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| 3. |
- Bourghardt Peebo, Beatrice, et al.
(författare)
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An in Vivo Method for Visualizing Flow Dynamics of Cells within Corneal Lymphatics
- 2013
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Ingår i: Lymphatic Research and Biology. - : Mary Ann Liebert. - 1539-6851 .- 1557-8585. ; 11:2, s. 93-100
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Tidskriftsartikel (refereegranskat)abstract
- Background: Monitoring the trafficking of specific cell populations within lymphatics could improve our understanding of processes such as transplant rejection and cancer metastasis. Current methods, however, lack appropriate image resolution for single-cell analysis or are incompatible with in vivo and longitudinal monitoring of lymphatics in their native state. We therefore sought to achieve high-resolution live imaging of the dynamic behavior of cells within lymph vessels in the rat cornea.Methods/Results: Inflammatory angiogenesis was induced by suture placement in corneas of Wistar rats. Pre- and up to 3 weeks post-induction, corneas were noninvasively examined by laser-scanning in vivo corneal confocal microscopy (IVCM) using only endogenous contrast. Lymph vessels and the cells harbored therein were documented by still images, real-time video, and 3D confocal stack reconstruction of live tissue. In vivo, conjunctival and corneal lymphatics were morphologically distinct, those with corneal location being one-quarter the diameter of those in the conjunctiva (p<0.001). Cells were recruited to initially empty pre-existing lymph vessels during the first day of inflammation and maintained a dense occupation of vessels for up to 7 days. A diverse population of cells (diameter range: 1.5–27.5 μm) with varying morphology was observed, and exhibited variable flow patterns and were transported singly and in clusters of at least 2–9 adherent cells.Conclusions: The in vivo microscopic technique presented enables lymph vessels and cell trafficking to be studied in high resolution in a minimally-perturbed physiologic milieu.
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| 4. |
- Bourghardt Peebo, Beatrice, 1968-
(författare)
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Angiogenesis from a new perspective
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Angiogenesis is the emergence of new blood and lymph vessels from existing ones. In the pathologic form it contributes to the onset and progression of numerous different human disorders such as cancer, inflammation, atherosclerosis and blinding eye diseases. There exist a number of models to study angiogenesis, both in vitro and in vivo, but there is no single perfect model so far. Consequently there is a need to develop new angiogenesis assays for evaluating blood and lymph vessel behaviour in different physiologic settings.The aim of this thesis was to gain insight into in vivo angiogenesis introducing a new technique in an inflammatory corneal model. The method involved in vivo examination of the cornea and subsequent comparison of in vivo findings with ex vivo immunohistochemical analysis of the same tissue samples. An existing suture model for inflammatory angiogenesis in the cornea was modified for in vivo observations with a clinically-approved corneal confocal microscope.In this thesis, corneal lymph vessels were characterized for the first time in vivo and findings from the experimental bench could be applied in a clinical setting, where presumed lymphatics were observed in a corneal transplant patient with rejection. Furthermore, the technique was extended to investigate time-lapse processes in sprouting and regressing capillaries, and led to a number of new observations. CD11b+ myeloid cells constitute the first bulk of infiltrating inflammatory cells and contribute to inflammatory sprouting and regression in numerous ways including pre-patterning of the corneal stroma and guiding of capillary sprouts. Newly formed hemangiogenic sprouts are perfused with a slow-moving fluid and have a lumen. In blood vessel regression, capillary remodeling occurred by abandonment of sprout tips in close association with macrophages and vascular loops formed by presumed intussusceptive angiogenesis. In addition, a network of pericyte- and endothelium-free basement membrane tubes was formed after desertion or degradation of vascular endothelium in former corneal capillaries.In conclusion, we introduce a new in vivo technique for investigating angiogenesis in a corneal model were in vivo findings can be interpreted with ex vivo definitions of specific cell types by immunohistochemistry. Findings from pre-clinical experiments have been possible to apply in a clinical setting when examining patients with corneal pathology.
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| 5. |
- Bourghardt Peebo, Beatrice, et al.
(författare)
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Cellular level characterization of capillary regression in inflammatory angiogenesis using an in vivo corneal model
- 2011
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Ingår i: Angiogenesis. - : Springer Verlag (Germany). - 0969-6970 .- 1573-7209. ; 14:3, s. 393-405
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we introduce a technique for repeated, microscopic observation of single regressing capillaries in vivo in inflamed murine corneas. Natural capillary regression was initiated by removal of inflammatory stimulus during an active pro-angiogenic phase, while the additional impact of anti-angiogenic treatment with triamcinolone or bevazicumab was investigated. Capillaries regressed naturally within 1 week and treatments did not further enhance the natural regression. Morphologically, early-phase regression was characterized by significant lumen narrowing and a significant reduction in CD11b+ myeloid cell infiltration of the extracellular matrix. By 1 week, vascular remodeling occurred concomitant with CD11b+CD68+KiM2R+ mature macrophage localization on capillary walls. Empty conduits without blood flow, positive for collagen IV and devoid of vascular endothelium and pericytes, were apparent in vivo and by 3 weeks were more numerous than perfused capillaries. By 3 weeks, macrophages aggregated around remaining perfused capillaries and were observed in apposition with degrading capillary segments. Abrupt termination of capillary sprouting in our regression model further revealed vascular endothelial abandonment of sprout tips and perfused capillary loop formation within a single angiogenic sprout, possibly as an intussusceptive response to cessation of the stimulus. Finally, we observed lumen constriction and macrophage localization on capillary walls in vivo in a clinical case of corneal capillary regression that paralleled findings in our murine model.
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| 6. |
- Bourghardt Peebo, Beatrice, et al.
(författare)
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Cellular-Level Characterization of Lymph Vessels in Live, Unlabeled Corneas by In Vivo Confocal Microscopy
- 2010
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Ingår i: Investigative Ophthalmology and Visual Science. - Rockville, MD, United States : Association for Research in Vision and Ophthalmology (ARVO). - 0146-0404 .- 1552-5783. ; 51:2, s. 830-835
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE. To determine whether in vivo confocal microscopy (IVCM) of the cornea can be used for the label-free detection and monitoring of lymph vessels in live corneas.METHODS. Parallel corneal hemangiogenesis and lymphangiogenesis was induced by the placement of a single suture in one cornea of male Wistar rats. Fourteen days after suture placement and under general anesthesia, laser-scanning IVCM was performed in the vascularized region. Corneas were subsequently excised for flat-mount double immunofluorescence with a pan-endothelial marker (PECAM-1/CD31) and a lymphatic endothelial specific marker (LYVE-1). Using the suture area and prominent blood vessels as points of reference, the identical microscopic region was located in both fluorescent and archived in vivo images. Additionally, vessel diameter, lumen contrast, and cell diameter and velocity within vessels were quantified from in vivo images.RESULTS. Comparison of identical corneal regions in fluorescence and in vivo revealed prominent CD31(+)/LYVE-1(3+) lymph vessels that were visible in vivo. In vivo, corneal lymph vessels were located in the vascularized area in the same focal plane as blood vessels but had a darker lumen (P andlt; 0.001) sparsely populated by highly reflective cells with diameters similar to those of leukocytes in blood vessels (P = 0.61). Cell velocity in lymph vessels was significantly reduced compared with blood particle velocity (P andlt; 0.001). Morphologic characteristics enabled subsequent identification of corneal lymphatics in live, vascularized rat corneas before immunofluorescence labeling.CONCLUSIONS. IVCM enabled the nondestructive, label-free, in vivo detection of corneal lymphatics. IVCM provides the possibility of observing lymphatic activity in the same live corneas longitudinally and, as a clinical instrument, of monitoring corneal lymphatics in live human subjects.
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| 7. |
- Bourghardt Peebo, Beatrice, 1968-, et al.
(författare)
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Expression of the focal adhesion protein PINCH in normal and alkali-injured corneas and the role of PMNs
- 2007
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Ingår i: Acta Ophthalmologica Scandinavica. - : Wiley. - 1395-3907 .- 1600-0420. ; 85:4, s. 395-400
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate the role of particularly interesting new cysteine-histidine-rich protein (PINCH) in corneal wound healing and early neovascularization and to assess the influence of granulocytes. Methods: A standardized corneal alkali wound was inflicted under general anaesthesia to the right eye of 14 New Zealand White rabbits. Seven of the rabbits received i.v. 5 mg/kg fucoidin every 2 hours to prevent granulocytes from entering the wound area. After 36 hours, the rabbits were killed, the corneas excised, fixed in 4% formaldehyde and embedded in paraffin. The sections were double-stained with antibodies against PINCH and with haematoxylin. Results: In the normal cornea and limbus, PINCH was weakly expressed in the corneal epithelium and in a wedge of the conjunctival stroma. In the wounded corneas, PINCH expression was seen in the frontline of repopulating endothelial and epithelial cells, and in active keratocytes. The vascular endothelium and the granulocytes expressed PINCH, as did the conjunctival epithelium. In the fucoidin-treated rabbits, PINCH expression was markedly reduced. The vascular endothelial cells and the few granulocytes did not express PINCH in these rabbits. Conclusions: PINCH is only slightly expressed in the normal cornea. A corneal wound induces PINCH expression in the repopulating cells, in the vascular endothelial cells of the limbus, in the limbal epithelium and in the granulocytes. Exclusion of granulocytes reduces expression of PINCH and there is no expression at all in the vascular endothelium. © 2007 The Authors Journal compilation 2007 Acta Ophthalmol Scand.
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| 9. |
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| 10. |
- Bourghardt Peebo, Beatrice, et al.
(författare)
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Time-Lapse In Vivo Imaging of Corneal Angiogenesis: The Role of Inflammatory Cells in Capillary Sprouting
- 2011
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Ingår i: Investigative Ophthalmology and Visual Science. - : Research in Vision and Opthalmology. - 0146-0404 .- 1552-5783. ; 52:6, s. 3060-3068
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE. To elucidate the temporal sequence of events leading to new capillary sprouting in inflammatory corneal angiogenesis. METHODS. Angiogenesis was induced by corneal suture placement in Wistar rats. The inflamed region was examined by time-lapse in vivo confocal microscopy for up to 7 days. At 6 and 12 hours and 1, 2, 4, and 7 days, corneas were excised for flat mount immunofluorescence with primary antibodies for CD31, CD34, CD45, CD11b, CD11c, Ki-M2R, NG2, and alpha-SMA. From days 0 to 4, the in vivo extravasation and expansion characteristics of single limbal vessels were quantified. RESULTS. Starting hours after induction and peaking at day 1, CD45(+)CD11b(+) myeloid cells extravasated from limbal vessels and formed endothelium-free tunnels within the stroma en route to the inflammatory stimulus. Limbal vessel diameter tripled on days 2 to 3 as vascular buds emerged and transformed into perfused capillary sprouts less than 1 day later. A subset of spindle-shaped CD11b(+) myeloid-lineage cells, but not dendritic cells or mature macrophages, appeared to directly facilitate further capillary sprout growth. These cells incorporated into vascular endothelium near the sprout tip, co-expressing endothelial marker CD31. Sprouts had perfusion characteristics distinct from feeder vessels and many sprout tips were open-ended. CONCLUSIONS. Time-lapse in vivo corneal confocal microscopy can be used to track a temporal sequence of events in corneal angiogenesis. The technique has revealed potential roles for myeloid cells in promoting vessel sprouting in an inflammatory corneal setting.
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