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Characteristics and Young's Modulus of Collagen Fibrils from Expanded Skin Using Anisotropic Controlled Rate Self-Inflating Tissue Expander

Manssor NA, Radzi Z, Yahya NA, Mohamad Yusof L, Hariri F, Khairuddin NH, et al.

Skin Pharmacol Physiol, 2016;29(2):55-62.
PMID: 26836267 DOI: 10.1159/000431328

Mechanical properties of expanded skin tissue are different from normal skin, which is dependent mainly on the structural and functional integrity of dermal collagen fibrils. In the present study, mechanical properties and surface topography of both expanded and nonexpanded skin collagen fibrils were evaluated. Anisotropic controlled rate self-inflating tissue expanders were placed beneath the skin of sheep's forelimbs. The tissue expanders gradually increased in height and reached equilibrium in 2 weeks. They were left in situ for another 2 weeks before explantation. Expanded and normal skin samples were surgically harvested from the sheep (n = 5). Young's modulus and surface topography of collagen fibrils were measured using an atomic force microscope. A surface topographic scan showed organized hierarchical structural levels: collagen molecules, fibrils and fibers. No significant difference was detected for the D-banding pattern: 63.5 ± 2.6 nm (normal skin) and 63.7 ± 2.7 nm (expanded skin). Fibrils from expanded tissues consisted of loosely packed collagen fibrils and the width of the fibrils was significantly narrower compared to those from normal skin: 153.9 ± 25.3 and 106.7 ± 28.5 nm, respectively. Young's modulus of the collagen fibrils in the expanded and normal skin was not statistically significant: 46.5 ± 19.4 and 35.2 ± 27.0 MPa, respectively. In conclusion, the anisotropic controlled rate self-inflating tissue expander produced a loosely packed collagen network and the fibrils exhibited similar D-banding characteristics as the control group in a sheep model. However, the fibrils from the expanded skin were significantly narrower. The stiffness of the fibrils from the expanded skin was higher but it was not statistically different.

Matched MeSH terms: Collagen/ultrastructure
Fulltext Comparative Study of The Yield and Physicochemical Properties of Collagen from Sea Cucumber (Holothuria scabra), Obtained through Dialysis and the Ultrafiltration Membrane

Saallah S, Roslan J, Julius FS, Saallah S, Mohamad Razali UH, Pindi W, et al.

Molecules, 2021 Apr 28;26(9).
PMID: 33924820 DOI: 10.3390/molecules26092564

Collagen was extracted from the body wall of sea cucumber (Holothuria scabra) using the pepsin-solubilized collagen method followed by isolation using dialysis and the ultrafiltration membrane. The yield and physicochemical properties of the collagen obtained from both isolation methods, denoted as D-PSC and UF-PSC, were compared. The ultrafiltration method affords a higher yield of collagen (11.39%) than that of the dialysis (5.15%). The isolated collagens have almost the same amino acid composition, while their functional groups, referred to as amide A, B, I, II, and III bands, were in accordance with commercial collagen, as verified by Fourier Transform Infrared (FT-IR) spectroscopy. The UV-Vis absorption peaks at 240 nm and 220 nm, respectively, indicated that the collagens produced are type-I collagen. The D-PSC showed interconnecting sheet-like fibrils, while the UF-PSC exhibited a flaky structure with flat-sheets arranged very close to each other. The higher yield and comparable physicochemical properties of the collagen obtained by ultrafiltration as compared with dialysis indicate that the membrane process has high potential to be used in large-scale collagen production for food and pharmaceutical applications.

Matched MeSH terms: Collagen/ultrastructure
Fulltext Quantitative intrinsic auto-cathodoluminescence can resolve spectral signatures of tissue-isolated collagen extracellular matrix

Zielinski MS, Vardar E, Vythilingam G, Engelhardt EM, Hubbell JA, Frey P, et al.

Commun Biol, 2019;2:69.
PMID: 30793047 DOI: 10.1038/s42003-019-0313-x

By analyzing isolated collagen gel samples, we demonstrated in situ detection of spectrally deconvoluted auto-cathodoluminescence signatures of specific molecular content with precise spatial localization over a maximum field of view of 300 µm. Correlation of the secondary electron and the hyperspectral images proved ~40 nm resolution in the optical channel, obtained due to a short carrier diffusion length, suppressed by fibril dimensions and poor electrical conductivity specific to their organic composition. By correlating spectrally analyzed auto-cathodoluminescence with mass spectroscopy data, we differentiated spectral signatures of two extracellular matrices, namely human fibrin complex and rat tail collagen isolate, and uncovered differences in protein distributions of isolated extracellular matrix networks of heterogeneous populations. Furthermore, we demonstrated that cathodoluminescence can monitor the progress of a human cell-mediated remodeling process, where human collagenous matrix was deposited within a rat collagenous matrix. The revealed change of the heterogeneous biological composition was confirmed by mass spectroscopy.

Matched MeSH terms: Collagen/ultrastructure
The effects of oestradiol and relaxin on extensibility and collagen organisation of the pregnant rat cervix

Cheah SH, Ng KH, Johgalingam VT, Ragavan M

J Endocrinol, 1995 Aug;146(2):331-7.
PMID: 7561646

The effects of exogenously introduced oestradiol-17 beta (E) and relaxin (RLX) on cervical extensibility and collagen organisation were tested in rats ovariectomised in late pregnancy. When the cervices were stretched in vitro by 1 mm increments, it was found that those from rats given E alone generated significantly higher tensions than those from control rats, while cervices from rats given both E and RLX had tensions similar to controls. Examination of cervical sections under the light microscope and ultra-thin sections under the electron microscope showed that the collagen fibres in the cervices from E-treated rats were highly organised, whereas those from animals given E+RLX and control animals were disorganised and dispersed. It was concluded that E decreased cervical extensibility, while RLX counteracted the effect of E to maintain a soft and easily extensible cervix.

Matched MeSH terms: Collagen/ultrastructure
AFM analysis of collagen fibrils in expanded scalp tissue after anisotropic tissue expansion

Aziz J, Ahmad MF, Rahman MT, Yahya NA, Czernuszka J, Radzi Z

Int J Biol Macromol, 2018 Feb;107(Pt A):1030-1038.
PMID: 28939521 DOI: 10.1016/j.ijbiomac.2017.09.066

Successful use of tissue expanders depends on the quality of expanded tissue. This study evaluates the impact of anisotropic self-inflating tissue expander (SITE) on the biomechanics of skin. Two different SITE were implanted subcutaneously on sheep scalps; SITE that requires 30days for maximum expansion (Group A; n=5), and SITE that requires 21days for maximum expansion (Group B; n=5). Control animals (n=5) were maintained without SITE implantation. Young's Modulus, D-periodicity, overlap and gap region length, diameter, and height difference between overlap and gap regions on collagen fibrils were analyzed using atomic force microscopy. Histology showed no significant differences in dermal thickness between control and expanded skin of groups A and B. Furthermore, most parameters of expanded skin were similar to controls (p>0.05). However, the height difference between overlap and gap regions was significantly smaller in group B compared to both control and group A (p<0.01). Strong correlation was observed between Young's Modulus of overlap and gap regions of the control and group A, but not group B. Results suggest that a relatively slower SITE can be useful in reconstructive surgery to maintain the biomechanical properties of expanded skin.

Matched MeSH terms: Collagen/ultrastructure
Fulltext Molecular Mechanisms of Stress-Responsive Changes in Collagen and Elastin Networks in Skin

Aziz J, Shezali H, Radzi Z, Yahya NA, Abu Kassim NH, Czernuszka J, et al.

Skin Pharmacol Physiol, 2016;29(4):190-203.
PMID: 27434176 DOI: 10.1159/000447017

Collagen and elastin networks make up the majority of the extracellular matrix in many organs, such as the skin. The mechanisms which are involved in the maintenance of homeostatic equilibrium of these networks are numerous, involving the regulation of genetic expression, growth factor secretion, signalling pathways, secondary messaging systems, and ion channel activity. However, many factors are capable of disrupting these pathways, which leads to an imbalance of homeostatic equilibrium. Ultimately, this leads to changes in the physical nature of skin, both functionally and cosmetically. Although various factors have been identified, including carcinogenesis, ultraviolet exposure, and mechanical stretching of skin, it was discovered that many of them affect similar components of regulatory pathways, such as fibroblasts, lysyl oxidase, and fibronectin. Additionally, it was discovered that the various regulatory pathways intersect with each other at various stages instead of working independently of each other. This review paper proposes a model which elucidates how these molecular pathways intersect with one another, and how various internal and external factors can disrupt these pathways, ultimately leading to a disruption in collagen and elastin networks.

Matched MeSH terms: Collagen/ultrastructure*
Fulltext A three-dimensional collagen construct to model lipopolysaccharide-induced activation of BV2 microglia

Haw RT, Tong CK, Yew A, Lee HC, Phillips JB, Vidyadaran S

J Neuroinflammation, 2014 Jul 30;11:134.
PMID: 25074682 DOI: 10.1186/1742-2094-11-134

BACKGROUND: We report a novel method of culturing microglia in three dimension (3D) using collagen as a substrate. By culturing microglia within a matrix, we aim to emulate the physical state of microglia embedded within parenchyma.
METHODS: BV2 microglia cell suspensions were prepared with type I collagen and cast into culture plates. To characterise the BV2 microglia cultured in 3D, the cultures were evaluated for their viability, cell morphology and response to lipopolysaccharide (LPS) activation. Conventional monolayer cultures (grown on uncoated and collagen-coated polystyrene) were set up concurrently for comparison.
RESULTS: BV2 microglia in 3D collagen matrices were viable at 48 hrs of culture and exhibit a ramified morphology with multiplanar cytoplasmic projections. Following stimulation with 1 μg/ml LPS, microglia cultured in 3D collagen gels increase their expression of nitric oxide (NO) and CD40, indicating their capacity to become activated within the matrix. Up to 97.8% of BV2 microglia grown in 3D cultures gained CD40 positivity in response to LPS, compared to approximately 60% of cells grown in a monolayer (Pcollagen gels also showed increased mRNA and protein expression of inflammatory cytokines IL-6, TNF-α and the chemoattractant MCP-1 following LPS stimulation.
CONCLUSIONS: In summary, BV2 microglia cultured in 3D collagen hydrogels exhibit multiplanar cytoplasmic projections and undergo a characteristic and robust activation response to LPS. This culture system is accessible to a wide range of analyses and provides a useful new in vitro tool for research into microglial activation.

Matched MeSH terms: Collagen/ultrastructure
Collagen-coated polylactic-glycolic acid (PLGA) seeded with neural-differentiated human mesenchymal stem cells as a potential nerve conduit

Sulong AF, Hassan NH, Hwei NM, Lokanathan Y, Naicker AS, Abdullah S, et al.

Adv Clin Exp Med, 2014 May-Jun;23(3):353-62.
PMID: 24979505

Autologous nerve grafts to bridge nerve gaps pose various drawbacks. Nerve tissue engineering to promote nerve regeneration using artificial neural conduits has emerged as a promising alternative.

Matched MeSH terms: Collagen/ultrastructure
Fulltext Structural Studies of Epithelial Mesenchymal Transition Breast Tissues

Mohd Sobri SN, Abdul Sani SF, Sabtu SN, Looi LM, Chiew SF, Pathmanathan D, et al.

Sci Rep, 2020 02 06;10(1):1997.
PMID: 32029810 DOI: 10.1038/s41598-020-58932-5

At the supramolecular level, the proliferation of invasive ductal carcinoma through breast tissue is beyond the range of standard histopathology identification. Using synchrotron small angle x-ray scattering (SAXS) techniques, determining nanometer scale structural changes in breast tissue has been demonstrated to allow discrimination between different tissue types. From a total of 22 patients undergoing symptomatic investigations, different category breast tissue samples were obtained in use of surgically removed tissue, including non-lesional, benign and malignant tumour. Structural components of the tissues were examined at momentum transfer values between q = 0.2 nm-1 and 1.5 nm-1. From the SAXS patterns, axial d-spacing and diffuse scattering intensity were observed to provide the greatest discrimination between the various tissue types, specifically in regard to the epithelial mesenchymal transition (EMT) structural component in malignant tissue. In non-lesional tissue the axial period of collagen is within the range 63.6-63.7 nm (formalin fixed paraffin embedded (FFPE) dewaxed) and 63.4 (formalin fixed), being 0.9 nm smaller than in EMT cancer-invaded regions. The overall intensity of scattering from cancerous regions is a degree of magnitude greater in cancer-invaded regions. Present work has found that the d-spacing of the EMT positive breast cancer tissue (FFPE (dewaxed)) is within the range 64.5-64.7 nm corresponding to the 9th and 10th order peaks. Of particular note in regard to formalin fixation of samples is that no alteration is observed to occur in the relative differences in collagen d-spacing between non-lesional and malignant tissues. This is a matter of great importance given that preserved-sample and also retrospective study of samples is greatly facilitated by formalin fixation. Present results indicate that as aids in tissue diagnosis SAXS is capable of distinguishing areas of invasion by disease as well as delivering further information at the supramolecular level.

Matched MeSH terms: Collagen/ultrastructure