Migrating Myofibroblastic Iliotibial Band-Derived Fibroblasts Represent a Promising Cell Source for Ligament Reconstruction.

The iliotibial band (ITB) is a suitable scaffold for anterior cruciate ligament (ACL) reconstruction, providing a sufficient mechanical resistance to loading. Hence, ITB-derived fibroblasts attract interest for ligament tissue engineering but have so far not been characterized. This present study aimed at characterizing ITB fibroblasts before, during, and after emigration from cadaveric ITB explants to decipher the emigration behavior and to utilize their migratory capacity for seeding biomaterials. ITB and, for comparison, ACL tissues were assessed for the content of alpha smooth muscle actin (αSMA) expressing fibroblasts and degeneration. The cell survival and αSMA expression were monitored in explants used for cell isolation, monolayer, self-assembled ITB spheroids, and spheroids seeded in polyglycolic acid (PGA) scaffolds. The protein expression profile of targets typically expressed by ligamentocytes (collagen types I-III, elastin, lubricin, decorin, aggrecan, fibronectin, tenascin C, CD44, ß1-integrins, vimentin, F-actin, αSMA, and vascular endothelial growth factor A [VEGFA]) was compared between ITB and ACL fibroblasts. A donor- and age-dependent differing percentage of αSMA positive cells could be detected, which was similar in ITB and ACL tissues despite the grade of degeneration being significantly higher in the ACL due to harvesting them from OA knees. ITB fibroblasts survived for several months in an explant culture, continuously forming monolayers with VEGFA and an increased αSMA expression. They shared their expression profile with ACL fibroblasts. αSMA decreased during the monolayer to spheroid/scaffold transition. Using self-assembled spheroids, the migratory capacity of reversible myofibroblastic ITB cells can be utilized for colonizing biomaterials for ACL tissue engineering and to support ligament healing.

Site specificity of mechanical and structural properties of human fascia lata and their gender differences: A cadaveric study.

The whole thigh muscles are covered with the fascia lata, which could have morphological and mechanical features that match the underlying muscles' functions. In this study, we investigated the morphological and elastic properties of the human fascia lata taken from four (anterior, medial, lateral, and posterior) sites on the thigh of 17 legs of 12 cadavers (6 males and 6 females, 75-92 years). The thickness of the fascia lata was determined with a caliper. The interwoven collagen fiber's directions were measured and classified into longitudinal, transverse, and diagonal in two opposing directions, relative to the thigh. Tensile strength test along the longitudinal and transverse directions was performed, and the stiffness, Young's modulus, and hysteresis were determined. Fascia lata at the lateral site (0.8 ±â€¯0.2 mm) was significantly thicker compared to other sites (0.2-0.3 mm). Fiber's directions showed substantial variability among sites, and longitudinally directed fibers were higher in proportion (28-32%) than those in other directions (20-27%) at all sites except for the posterior site. The stiffness and Young's modulus in the longitudinal direction (20-283 N/mm; 71.6-275.9 MPa, highest at the lateral site) were significantly higher than in the transverse direction (3-16 N/mm; 3.2-41.9 MPa, lowest at the lateral site). At the medial site, the proportion of the transversely directed fibers was higher in females than males, with higher stiffness and Young's modulus thereof. The present study shows that the fascia lata possesses site- and gender-dependence of the morphological characteristics and elastic properties.

The fasciacytes: A new cell devoted to fascial gliding regulation.

Hyaluronan occurs between deep fascia and muscle, facilitating gliding between these two structures, and also within the loose connective tissue of the fascia, guaranteeing the smooth sliding of adjacent fibrous fascial layers. It also promotes the functions of the deep fascia. In this study a new class of cells in fasciae is identified, which we have termed fasciacytes, devoted to producing the hyaluronan-rich extracellular matrix. Synthesis of the hyaluronan-rich matrix by these new cells was demonstrated by Alcian Blue staining, anti-HABP (hyaluronic acid binding protein) immunohistochemistry, and transmission electron microscopy. Expression of HAS2 (hyaluronan synthase 2) mRNA by these cells was detected and quantified using real time RT-PCR. This new cell type has some features similar to fibroblasts: they are positive for the fibroblast marker vimentin and negative for CD68, a marker for the monocyte-macrophage lineage. However, they have morphological features distinct from classical fibroblasts and they express the marker for chondroid metaplasia, S-100A4. The authors suggest that these cells represent a new cell type devoted to the production of hyaluronan. Since hyaluronan is essential for fascial gliding, regulation of these cells could affect the functions of fasciae so they could be implicated in myofascial pain. Clin. Anat. 31:667-676, 2018. © 2018 Wiley Periodicals, Inc.

Enhanced vascular biocompatibility of decellularized xeno-/allogeneic matrices in a rodent model.

Glutaraldehyde preservation is the gold standard for cardiovascular biological prosthesis. However, secondary calcifications and the absence of tissue growth remain major limitations. Our study assessed in vitro and in vivo the biocompatibility of human (fascia lata, pericardium) and porcine tissues (pericardium, peritoneum) treated with a physicochemical procedure for decellularization and non-conventional pathogens inactivation. Biopsies were performed before and after treatment to assess decellularization (HE/Dapi staining/DNA quantification/MHC I/alpha gal immunostaining) and mechanical integrity. Forty-five rats received an abdominal aortic patch of native cryopreserved tissues (n = 20), treated tissues (n = 20) or glutaraldehyde-preserved bovine pericardium (GBP, control, n = 5). Grafts were explanted at 4 weeks and processed for HE/von Kossa staining and immunohistochemistries for lymphocytes (CD3)/macrophages (CD68) histomorphometry. 95% of decellularization was obtained for all tissues except for fascia lata (75%). Mechanical properties were slightly altered. In the in vivo model, a significant increase of CD3 and CD68 infiltrations was found in native and control implants in comparison with decellularized tissues (p < 0.05). Calcifications were found in 3 controls. Decellularized tissues were recolonized. GBP showed the most inflammatory response. This physicochemical treatment improves the biocompatibility of selected xeno/allogeneic tissues in comparison with their respective native cryopreserved tissues and with GBP. Incomplete decellularization is associated with a significantly higher inflammatory response. Our treatment is a promising tool in the field of tissue decellularization and tissue banking.

Electron microscopy of human fascia lata: focus on telocytes.

From the histological point of view, fascia lata is a dense connective tissue. Although extracellular matrix is certainly the most predominant fascia's feature, there are also several cell populations encountered within this structure. The aim of this study was to describe the existence and characteristics of fascia lata cell populations viewed through a transmission electron microscope. Special emphasis was placed on telocytes as a particular interstitial cell type, recently discovered in a wide variety of tissues and organs such as the heart, skeletal muscles, skin, gastrointestinal tract, uterus and urinary system. The conducted study confirmed the existence of a telocyte population in fascia lata samples. Those cells fulfil main morphological criteria of telocytes, namely, the presence of very long, thin cell processes (telopodes) extending from a relatively small cell body. Aside from telocytes, we have found fibroblasts, mast cells and cells with features of myofibroblastic differentiation. This is the first time it has been shown that telocytes exist in human fascia. Currently, the exact role of those cells within the fascia is unknown and definitely deserves further attention. One can speculate that fascia lata telocytes likewise telocytes in other organs may be involved in regeneration, homeostasis and intracellular signalling.

Human fascia lata ECM scaffold augmented with immobilized hyaluronan: inflammatory response and remodeling in the canine body wall and shoulder implantation sites.

We postulate that immobilization of tyramine-substituted hyaluronan (THA) into an extracellular matrix (ECM) scaffold may be a strategy to promote an anti-inflammatory response to the ECM. Further, we posit that the implantation site could influence the inflammatory response and remodeling of an ECM scaffold. Eight beagles underwent implantation of fascia ECM grafts, treated with either immobilized low molecular weight (57 kDa) THA or water only, in both the shoulder injury and body wall sites. Dogs were euthanized at 12 weeks and fascia grafts harvested en bloc for histology. Grafts implanted at the body wall had significantly higher inflammatory cell infiltrate and vascularity, and significantly lower retardance (collagen density), than grafts at the shoulder, suggestive of a more intense, persistent, and perhaps degradative inflammatory and remodeling response at the body wall than shoulder injury site in the canine model. However, the presence of immobilized low MW THA had no effect on the inflammation response or remodeling of fascia ECM compared to water-treated controls. Importantly, these results suggest that the inflammatory response and remodeling of biomaterial implants depends on the location of implantation and therefore our animal models need to be carefully chosen. Further, the potential anti-inflammatory advantages of hyaluronan (HA) in wound healing do not appear to be realized when presenting it to the host as non-degradable hydrogel even if its capacity for binding HA binding protein is maintained. Further study treating ECM with uncross-linked (free) HA or immobilized low MW THA as a means to deliver free HA or other biomolecules to a surgical repair site is warranted.

A constitutive description of the anisotropic response of the fascia lata.

In this paper we propose a constitutive model to analyze in-plane extension of goat fascia lata. We first perform a histological analysis of the fascia that shows a well-organized bi-layered arrangement of undulated collagen fascicles oriented along two well defined directions. To develop a model consistent with the tissue structure we identify the absolute and relative thickness of each layer and the orientation of the preferred directions. New data are presented showing the mechanical response in uniaxial and planar biaxial extension. The paper proposes a constitutive relation to describe the mechanical response. We provide a summary of the main ingredients of the nonlinear theory of elasticity and introduce a suitable strain-energy function to describe the anisotropic response of the fascia. We validate the model by showing good fit of the numerical results and the experimental data. Comments are included about differences and analogies between goat fascia lata and the human iliotibial band.

Histological study of the deep fasciae of the limbs.

The aim of this study is to analyse the deep fasciae of limbs in order to evaluate the collagen and elastic fibre arrangement and the types of innervation. Histological and immunohistochemical stains were performed in 72 specimens. The deep fascia of the limbs is a sheath presenting a mean thickness of 1mm, formed by two to three layers of parallel collagen fibre bundles. In the adjacent layers, they show different orientations. Each layer is separated from the adjacent one by loose connective tissue, permitting the sliding of the collagen layers. Nerve fibres were found in all specimens, while muscular fibres were evidenced only in one specimen. The described structure permits the fasciae of the limbs to have a strong resistance to traction, even when exercised in different directions. The capacity of the different collagen layers to glide one on the other could be altered in cases of overuse syndrome, trauma, or surgery.

The effects of bone marrow-derived mesenchymal stem cells and fascia wrap application to anterior cruciate ligament tissue engineering.

After an anterior cruciate ligament (ACL) injury, surgical reconstructions are necessary in most cases, either with autografts, allografts, or artificial ligaments. Potential tissue-engineered ligaments would circumvent the disadvantages apparent in these methods. While seeding of mesenchymal stem cells (MSCs) and fascia wrap could potentially improve tissue regeneration and mechanical properties, their exact roles were evaluated in the current study. Knitted biodegradable scaffolds of poly-L-lactic acid (PLLA) and poly-glycolic-lactic acid (PGLA) yarns were used to reconstruct ACL in 48 rabbits. These were divided into four equal groups: only knitted scaffolds were used in group I; knitted scaffolds and mesenchymal stem cells were used in group II; knitted scaffolds, MSCs, and fascia lata were used in group III; knitted scaffolds and fascia lata were used in group IV. Carboxyfluorescein diacetate (CFDA)-labeled MSCs were used to trace the fate of seeded cells in groups II and III. Histology, Western blot analysis, and mechanical properties of reconstructed ACL were analyzed after 20 weeks. Fibroblast ingrowths were seen in all four groups while CFDA-labeled MSCs could be found after 8 weeks of implantation in groups II and III. Both the amount of collagen type I and collagen type III in groups III and IV were significantly higher than in group II, which was much higher than in group I. Both maximal tensile loads and stiffness of the reconstructed ACLs in groups I, II, III, and IV were significantly lower than normal controls after 20 weeks of implantation. It is concluded that MSCs could promote synthesis of collagen type I and collagen type III in tissue-engineered ligaments, while fascia wraps have stronger effects. Both MSC seeding and fascia wrap could not enhance ultimate tensile load and stiffness.

Basic research conducted on alloplant biomaterials.

PURPOSE: To reduce antigenicity of allografts and stimulate their replacement by natural recipient tissues. METHODS: Experimental allotransplantation of different tissues (fascias, tendons, derma, fat, etc.) with histological, histochemical, electron microscopical, electron histochemical examination 3, 5, 7, 14, 21, 30, 60, 120, 180 and 360 days postoperatively. RESULTS: Allografts of different tissues with glucosaminoglycans extracted from collagen fibers have low antigenicity and can be replaced by natural tissues. Allografts with these properties were named 'Alloplant'. CONCLUSIONS: Alloplant biomaterials can selectively stimulate natural tissue regeneration. Hence, Alloplant biomaterials can be utilized in surgery for the restoration of different tissues.

Adhesion of intermediate filaments and lipid droplets in adrenal cells studied by field emission scanning electron microscopy.

High-resolution field emission scanning electron microscopy was used to study the organisation of intermediate filaments around lipid droplets and their binding to these droplets, in primary culture of bovine adrenal cells. Whole-mount preparations of intermediate filaments and bound lipid droplets were prepared from cells grown on Formvar-coated grids and processed by freeze-drying. Intermediate filaments were seen as an interconnected network enveloping the entire droplet. The bound filaments appear to be directly adherent to the surface of the droplet and hence take on its curved contour. The binding of the filaments to the droplets was determined by means of tilting. This study provides a new approach to investigate the cytoskeleton and its associated structures with high-resolution three-dimensional images.

Enhancement of periosteal chondrogenesis in vitro. Dose-response for transforming growth factor-beta 1 (TGF-beta 1).

Transforming growth factor-beta 1 (TGF-beta 1) has been shown to stimulate chondrogenesis in periosteal explants cultured in agarose suspension. In this study, the dose-response curve for such enhancement was measured. Periosteal explants and fascia lata were harvested from two-month-old rabbits, cultured for six weeks with 0, 0.1, 1, 5, 10, 50, or 100 ng/mL TGF-beta 1 in agarose suspension, then analyzed by histomorphometry and quantitative collagen typing. Cartilage was produced by seven of 11 (64%) of the control periosteal explants cultured in agarose suspension without TGF-beta 1. Transforming growth factor-beta 1 enhanced chondrogenesis in a dose-dependent manner in the range 0.1-100 ng/mL. It was most effective at 50 ng/mL. At very high doses (50 and 100 ng/mL) of TGF-beta 1, even fascia lata control explants exhibited chondrogenesis. These data indicate that TGF-beta 1 can induce differentiation toward cartilage production as well as enhance it once it has been initiated.

The fate of free autogenous fascial grafts in the rabbit.

Fascial grafts were taken from 34 New Zealand rabbits and implanted above and below the cranial periosteum in the same animal. They were placed as four-layered folded grafts and as single-layered grafts. When harvested from 6 to 14 months after transplantation, the multi-layered grafts and the single-layered grafts on bone had maintained their bulk but consisted histologically of only a retained collagen matrix with no viable cellular structure. The one-layered grafts on periosteum, however, retained their cellular make-up with normal vascularity and normal cellular structure when harvested at approximately the same intervals.

The use and fate of fascia lata and sclera in ophthalmic plastic and reconstructive surgery.

The introduction and use of newer surgical materials, better surgical instruments, finer suture materials, and improved optical equipment have allowed us to advance certain techniques in ophthalmic surgery and ophthalmic plastic surgery. In oculoplastic surgery, fascia lata and sclera are but a few of these materials used with greater frequency. In this paper, a number of techniques are described depicting the use of fascia lata and sclera. A histologic study of these materials after variable periods of implantation is presented.

Viability properties in autologous fascia lata heart valve grafts: a transmission electron microscopical study.

Four frame-mounted autologous fascia lata heart valve grafts in situ for 18 to 41 months as well as one free-mounted fascia cusp in situ for 10 years were examined by transmission electron microscopy (TEM). In all cusps, areas of well-preserved subcellular structures were found as well as areas with degeneration and fragmentation of both nuclear and collagen fibers. Fibrocytes, fibroblasts, and a special cell form, the myofibroblast, were encountered. The appearance of this last cell form may explain the shrinkage phenomenon encountered in these valves, all retrieved at reoperation because of valve dysfunction. Some of the fascial cells thus stayed alive within the bloodstream for up to 10 years.