Collagen fibre orientation in human bridging veins

Abstract

Bridging veins (BV) drain the blood from the cerebral cortex into dural sinuses. BV have one end attached to the brain and the other to the superior sagittal sinus (SSS), which is attached to the skull. Relative movement between these two structures can cause BV to rupture producing acute subdural haematoma (ASDH), a head injury with a mortality rate between 30 and 90%. A clear understanding of the BV's microstructure is required to increase the biofidelity of BV models when simulating head impacts.Twelve fresh BV samples draining in the superior sagittal sinus (SSS) from a single human cadaver were cut open along their length and placed on an inverted multiphoton microscope. To ensure that the BV were aligned with the axial direction an in-house built, uniaxial tension set up was used. Two scans were performed per sample. Before the first scan, a minor displacement was applied to align the tissue, then a second scan was taken applying 50% strain. Each BV was scanned for a length of 5 mm starting from the drainage site into the SSS. Imaging was performed on a Zeiss LSM780 microscope with an 25x water immersion objective (NA 0.8), coupled to a tunable MaiTai DS (Spectraphysics) pulsed laser with the wavelength set at 850 nm. Second harmonic and fluorescence signals were captured in forward and backward direction on binary GaAsP (BiG) detectors and stored as four colour Z-stacks. Prior to the calculation of the local orientations, acquired Z-stacks were denoised and enhanced to highlight fibrillar structures from the background. Then, for each Z-plane of the stack, the ImageJ plugin OrientationJ was used to extract the local 2D orientations of the fibres based on structure tensors.Two kinds of collagen architectures were seen. The most common (8/12 samples) was single layered and had a uniform distribution of collagen. The less common (4/12 samples) had 2 layers and 7 to 34 times thicker collagen bundles on the outer layer. Fibre angle analysis showed that collagen was oriented mainly along the axial direction of the vessel. The von Mises fittings showed that in order to describe the fibre distribution 3 components were needed with mean angles µ at -0.35, 0.21, -0.02 rad or -20.2 • , 12.1 • , -1.2 • relative to the vessel's axial direction which was also the horizontal scan direction.

Magnetic resonance cisternography imaging findings related to the leakage of Gadolinium into the subarachnoid space

“…Furthermore, quantification of BVs is more objective than quantification of cystic structures, given that cystic structures are challenging to identify due to difficulties in tracing cyst edges. BVs, by definition, connect the cortical veins to the SSS [15]. In addition, we use BVs ≥ 3 mm in diameter and cystic structures or AGs within 1 cm of the confluence as inclusion criteria for more objective quantification.…”

Verständnis, Prävention und Behandlung von venösen und lymphatischen Erkrankungen basieren auf der Arbeit von Grundlagenforschern

“…Interessanterweise ordnen sich Kollagenfasern in der 3-dimensionalen Struktur der durch den Umbau veränderten Venenwand an. Diese Studie wurde jedoch durchgeführt, um Brückenvenen (BV) zu untersuchen, die das Blut aus der Hirnrinde in die Sinus der Dura-Mater ableiten, und hat die Bedeutung der Anordnung von Kollagenfasern dieser Venen nach einem Gewebeumbau aufgezeigt [9]. In Varizen kommt es bei den Kollagenfasern durch die veränderte räumliche Anordnung zu einer Lücke mit einem möglichen Zusammenhang mit Risikofaktoren.…”

“…Interestingly, the collagen fibers have a natural disposition to the tridimensional structure of the vein walls that is altered due to tissue remodeling. Despite that, this study was conducted to study bridging veins (BVs), which drain the blood from the cerebral cortex into the Dural sinuses, demonstrating the importance of collagen fiber disposition on those veins after tissue remodeling head impact [9]. Thus, there is a gap in collagen fibersʼ spatial configuration changes in varicose veins and a potential link to risk factors.…”

The Use of Contravariant Tensors to Model Anisotropic Soft Tissues

“…Collagen fibres have also been shown to have a significant role in the intralamellar bonding of tissues [36]. Histological studies have revealed that the seemingly disordered distribution of collagen fibres in a tissue, can actually be shown to have a mean orientation which are not aligned along the main loading directions of a tissue [37], [38], [33], [39]. These studies on the orientation of collagen fibres clearly reveal a general oblique alignment of the fibres with respect to the direction of loading.…”