Sheet Of Tissue Research Articles

Early Fish Myoseptal Cells: Insights from the Trout and Relationships with Amniote Axial Tenocytes

The trunk muscle in fish is organized as longitudinal series of myomeres which are separated by sheets of connective tissue called myoseptum to which myofibers attach. In this study we show in the trout that the myoseptum separating two somites is initially acellular and composed of matricial components such as fibronectin, laminin and collagen I. However, myoseptal cells forming a continuum with skeletogenic cells surrounding axial structures are observed between adjacent myotomes after the completion of somitogenesis. The myoseptal cells do not express myogenic markers such as Pax3, Pax7 and myogenin but express several tendon-associated collagens including col1a1, col5a2 and col12a1 and angiopoietin-like 7, which is a secreted molecule involved in matrix remodelling. Using col1a1 as a marker gene, we observed in developing trout embryo an initial labelling in disseminating cells ventral to the myotome. Later, labelled cells were found more dorsally encircling the notochord or invading the intermyotomal space. This opens the possibility that the sclerotome gives rise not only to skeletogenic mesenchymal cells, as previously reported, but also to myoseptal cells. We furthermore show that myoseptal cells differ from skeletogenic cells found around the notochord by the specific expression of Scleraxis, a distinctive marker of tendon cells in amniotes. In conclusion, the location, the molecular signature and the possible sclerotomal origin of the myoseptal cells suggest that the fish myoseptal cells are homologous to the axial tenocytes in amniotes.

Regeneration of Periosteum by Human Bone Marrow Stromal Cell Sheets

The presence of a functional periosteum accelerates healing in bone defects by providing a source of progenitor cells that aid in repair. We hypothesized that bone marrow stromal cell (BMSC) sheets could be used to engineer functional periosteal tissues. BMSCs were cultured to hyperconfluence and produced sufficient extracellular matrix to form robust tissue sheets. The sheets were wrapped around calcium phosphate pellets and implanted subcutaneously in mice for 8 weeks. Histologic comparisons were made between calcium phosphate samples with and without BMSC sheet wraps. Bone and periosteum formation were analyzed through tissue morphology and tissue-specific protein expression. Calcium phosphate pellets wrapped in BMSC sheets regenerated a bone-like tissue, but pellets lacking the cell sheet wrap did not. The bone-like tissue seen on the calcium phosphate scaffolds wrapped with the BMSC sheets was enclosed within a periosteum-like tissue characterized morphologically and through expression of periostin. These data indicate that cell sheet technology has potential for regenerating a functional periosteum-like tissue that could aid in future orthopedic therapy.

The canine jaw‐ear connection: The malleomandibular and tympanomandibular ligaments

In the human, two ligaments derived from the first embryonic pharyngeal (branchial) arch that unite the mandible and temporomandibular joint (TMJ) with the middle ear have been identified as the discomalleolar ligament (DML) and sphenomandibular ligament (SML), also known as the malleomandibular ligament (MML), anterior ligament of the malleus (AML), and tympanomandibular ligament (TML). Neither of these structures has been previously described in the dog. The homologue of the human sphenomandibular ligament (SML) exists in the dog and is represented as a fibrous remnant of Meckel's cartilage. In the newborn puppy, the ligament is a true malleomandibular ligament (MML), extending from the medial mandible to the rostral process of the malleus with no intermittent attachments. In the adult dog, the ligament is entrapped within a bony passageway, likely due to the development and ossification of the tympanic bulla, making it difficult to grossly view the complete course of the ligament. The majority of the ligamentous fibers attach near the tympanic bulla in the adult dog, thus this portion of the ligament has been named the tympanomandibular ligament (TML). Those fibers of the ligament not attaching near the tympanic bulla appear to continue through a canal, located between the tympanic annulus and the surrounding tympanic bone, to become continuous with a connective tissue sheet within the cavity of the middle ear that has attachments to the malleus and incus. Tension on the adult canine TML did not result in movement of the malleus.

Anatomy and Adaptations of the Chewing Muscles in Daubentonia (Lemuriformes)

The extractive foraging behavior in aye-ayes (Daubentonia madagascariensis) is unique among primates and likely has led to selection for a specialized jaw adductor musculature. Although this musculature has previously been examined in a subadult, until now, no one has reported the fascicle length, weight, and physiological cross-sectional area (PCSA) for these muscles in an adult aye-aye specimen. For the present study, we dissected an adult wild-born aye-aye from the Tsimbazaza Botanical and Zoological Park, Antananarivo, Madagascar. The aye-aye follows the general strepsirrhine pattern in its overall jaw adductor muscle anatomy, but has very large muscles and PCSA relative to body size. Fascicle length is also relatively great, but not nearly as much as in the juvenile aye-aye previously dissected. Perhaps chewing muscle fascicles begin relatively long, but shorten through use and growth as connective tissue sheets expand and allow for pinnation and increased PCSA. Alternately, it may be that aye-ayes develop fascicular adaptation to wide gapes early in ontogeny, only to increase PCSA through later development into adulthood. The functional demands related to their distinctive manner of extractive foraging are likely responsible for the great PCSA in the jaw adductor muscles of the adult aye-aye. It may be that great jaw adductor PCSA in the adult, as compared to the juvenile, is a means of increasing foraging efficiency in the absence of parental assistance. Anat Rec, 297:308-316, 2014. © 2013 Wiley Periodicals, Inc.

Musculoskeletal morphology of the pelvis and pelvic fins in the lungfish Protopterus annectens.

The West African lungfish (Protopterus annectens) performs benthic, pelvic fin-driven locomotion with gaits common to tetrapods, the sister group of the lungfishes. Features of P. annectens movement are similar to those of modern tetrapods and include use of the distal region of the pelvic fin as a “foot,” use of the fin to lift the body above the substrate and rotation of the fin around the joint with the pelvis. In contrast to these similarities in movement, the pelvic fins of P. annectens are long, slender structures that are superficially very different from tetrapod limbs. Here, we describe the musculoskeletal anatomy of the pelvis and pelvic fins of P. annectens with dissection, magnetic resonance imaging, histology and 3D-reconstruction methods. We found that the pelvis is embedded in the hypaxial muscle by a median rostral and two dorsolateral skeletal projections. The protractor and retractor muscles at the base of the pelvic fin are fan-shaped muscles that cup the femur. The skeletal elements of the fin are serially repeating cartilage cylinders. Along the length of the fin, repeating truncated cones of muscles, the musculus circumradialis pelvici, are separated by connective tissue sheets that connect the skeletal elements to the skin. The simplicity of the protractor and retractor muscles at the base of the fin is surprising, given the complex rotational movement those muscles generate. In contrast, the series of many repeating segmental muscles along the length of the fin is consistent with the dexterity of bending of the distal limb. P. annectens can provide a window into softtissue anatomy and sarcopterygian fish fin function that complements the fossil data from related taxa. This work, combined with previous behavioral examination of P. annectens, illustrates that fin morphologies that do not appear to be capable of walking can accomplish that function, and may inform the interpretation of fossil anatomical evidence.

Successful Long-Term Phenotypic Correction Of Hemophilia A Mice By Engineering Functional Factor VIII Delivery System In Vivo Using Autologous Endothelial Cell Sheets

Recently, preclinical and clinical studies using adeno-associated viral (AAV) vectors for hemophilia B showed that the safety profile is vector dose-dependent and that immune responses to AAV-capsid proteins with subsequent hepatocyte toxicity required transient immunosuppression for sustained transgene expression. However, there still remain concerns over the safety of systemic vector injection. Potential side effects include adverse immunological reactions, vector-mediated cytotoxicity, germ-line transmission, and insertional oncogenesis. Moreover, especially in hemophilia A, an alternative transgene delivery approach may be necessary due to the large size of the factor VIII (FVIII) cDNA.Blood outgrowth endothelial cells (BOECs) are considered to be an attractive candidate to treat hemophilia A, because BOECs express von Willebrand factor, which is known to act as a carrier protein for FVIII and prevents its proteolytic degradation. We previously reported that therapeutic levels of plasma FVIII were documented from hemophilia A mice over 6 months, in which lentivirally-engineered BOECs mixed with Matrigel were implanted subcutaneously. However, the gradual loss of plasma FVIII was observed probably due to the breakdown of the scaffold material or cell death. To overcome this issue, we employed a novel tissue engineering approach, in which BOECs were formed into a contiguous monolayer sheet that can readily used for transplantation into the subcutaneous space for the FVIII production. To evaluate alternative scaffold material that can enhance the viability of the implanted cells, FVIII-transduced BOECs were cultured on temperature-responsive poly (N-isopropylacrylamide) (PIPAAm)-grafted dish to engineer BOECs sheet. This dish allows for simple detachment of the cultured cells without the use of proteolytic enzymes such as trypsin and enables us to harvest the cell sheet as a contiguous monolayer that retains its native intercellular communications and intracellular microstructure, which are indispensable for normal cellular function. The lentivirally-modified BOECs that expressed canine FVIII at the level of 2,000-3,000 mU/mL /1x10 6 cells/24hrs in vitro were seeded on the temperature-responsive culture dishes. When the cultured BOECs reached confluency, the cultured cells were detached from the PIPPAm dish as a uniformly connected tissue sheet by lowering the culture temperature to 20°C for 30 minutes. Despite requiring a single plasma infusion at the time of the small surgical procedure and transient immunosuppression with cyclophosphamide, 2-11% FVIII levels of normal plasma were detected 3 weeks after cell transplantation and sustained up to 300 days without the development of anti-canine FVIII antibodies in immunocompetent hemophilia A mice receiving the transplanted BOECs sheet. In addition, by histological examination, we also confirmed that transplanted the BOECs differentiate into mature endothelial cells and contribute to new blood vessel formation. There is a clear difference in cell viability between our previous Matrigel transplantation approach and this new cell sheet strategy. Although BOECs are capable of engrafting and expressing FVIII following transplantation into the same subcutaneous space, BOECs implanted through the cell sheet approach exhibit prolonged cell viability that results in both long-term and 3-5 times higher expression of FVIII.In conclusion, we have succeeded in the long-term correction of hemophilia A in a mouse model by ex vivo engineering of genetically-modified autologous endothelial cells in an ectopic subcutaneous space. Our cell sheet engineering approach could contribute to clinical translational studies for hemophilia A in a variety of therapeutic settings. Disclosures:No relevant conflicts of interest to declare.

Advantage of Crescent Knife in Making Excision of Pterygium

A pterygium is a triangular sheet of fibrovascular tissue which invades the cornea. In the management of pterygium surgical excision is needed. Common practices in pterygium surgery are simple excision, excision with post operative b- radiation or tropical thio-TEPA solution(1:2000) or mitomycin-C solution(0.4%), excision with peroperative use of mitomycin-C or conjunctival autograft or amneotic membrane graft or lamellar keratoplasty of the affected part of the cornea. Recurrence is high in pterygium surgery probably due to facing difficulty for easy and complete separation of fibrovascular growth. So this is a search for new technique where easy smooth and complete separation pterygial tissue can be done with minimum surgical trauma and a good cosmetic look. This study was carried out at Faridpur Medical College Hospital (FMCH) from January 2010 to December 2011. A total 50 cases were selected for study. Technique of operation in all the cases were excision of pterygium with conjunctival autograft. In 50% cases, the head of the pterygium removed from the cornea with crescent knife and in 50% cases the head of the pterygium removed with tooks knife. The follow up period was 12 to 24 months. In the group- A, recurrence occurred in two eyes i.e 8% and succeed in 23 eyes i.e 92%. In the group-B, recurrence occurred in 6 eyes i.e 24% and succeed in 19 eyes i.e. 76%. So, higher success rate and low recurrence rate with good cosmetic look and minimum surgical trauma for those where crescent knife were used. DOI: http://dx.doi.org/10.3329/fmcj.v8i1.16888 Faridpur Med. Coll. J. 2013;8(1): 05-06

Revealed in the Wound

Revealed in the Wound

Characterization of a Liver Organoid Tissue Composed of Hepatocytes and Fibroblasts in Dense Collagen Fibrils

The adult liver is wrapped in a connective tissue sheet called the liver capsule, which consists of collagen fibrils and fibroblasts. In this study, we set out to construct a liver organoid tissue that would be comparable to the endogenous liver, using a bioreactor. In vitro liver organoid tissue was generated by combining collagen fibrils, fibroblasts, and primary murine hepatocytes or Hep G2 on a mesh of poly-lactic acid fabric using a bioreactor. Then, the suitability of this liver organoid tissue for transplantation was tested by implanting the constructs into partially hepatectomized BALB/cA-nu/nu mice. As determined by using scanning and transmission electron microscopes, the liver organoid tissues were composed of densely packed collagen fibrils with fibroblasts and aggregates of oval or spherical hepatocytes. Angiogenesis was induced after the transplantation, and blood vessels connected the liver organoid tissue with the surrounding tissue. Thus, a novel approach was applied to generate transplantable liver organoid tissue within a condensed collagen fibril matrix. These results suggested that a dense collagen network populated with fibroblasts can hold a layer of concentrated hepatocytes, providing a three-dimensional microenvrionment suitable for the reestablishment of cell-cell and cell-extracellular matrix (ECM) interactions, and resulting in the maintenance of their liver-specific functions. This liver organoid tissue may be useful for the study of intrahepatic functions of various cells, cytokines, and ECMs, and may fulfill the fundamental requirements of a donor tissue.

Combined Photoacoustic and Acoustic Imaging of Human Breast Specimens in the Mammographic Geometry

A photoacoustic volume imaging (PAVI) system was designed to study breast cancer detection and diagnosis in the mammographic geometry in combination with automated 3-D ultrasound (AUS). The goal of the work described here was to validate the design and evaluate its performance in human breast tissues for non-invasive imaging of deeply positioned structures covering such geometry. The good penetration of near-infrared light and high receiving sensitivity of a broad-bandwidth, 572-element, 2-D polyvinylidene fluoride (PVDF) array at a low center frequency of 1MHz were used with 20 channel simultaneous acquisition. Pseudo-lesions filled with dilute blood were imaged in three human breast specimens at various depths up to 49mm. With near-infrared light illumination and 256-sample averaging, the extrapolated maximum depth in imaging a 2.4-mm blood-rich lesion with a 3-dB contrast-to-noise ratio in a compressed breast was 54mm. Three-dimensional photoacoustic volume image stacks of the breasts were co-registered with 3-D ultrasound image stacks, suggesting for the first time that PAVI, based on the intrinsic tissue contrast, can visualize tissue interfaces other than those with blood, including the inner skin surface and connective tissue sheets. With the designed system, PAVI revealed satisfactory imaging depth and sensitivity for coverage of the entire breast when imaged from both sides in the mammographic geometry with mild compression.

Functional expression of KCNQ (Kv7) channels in guinea pig bladder smooth muscle and their contribution to spontaneous activity

Background and PurposeThe aim of the study was to determine whether KCNQ channels are functionally expressed in bladder smooth muscle cells (SMC) and to investigate their physiological significance in bladder contractility.Experimental ApproachKCNQ channels were examined at the genetic, protein, cellular and tissue level in guinea pig bladder smooth muscle using RT-PCR, immunofluorescence, patch-clamp electrophysiology, calcium imaging, detrusor strip myography, and a panel of KCNQ activators and inhibitors.Key ResultsKCNQ subtypes 1–5 are expressed in bladder detrusor smooth muscle. Detrusor strips typically displayed TTX-insensitive myogenic spontaneous contractions that were increased in amplitude by the KCNQ channel inhibitors XE991, linopirdine or chromanol 293B. Contractility was inhibited by the KCNQ channel activators flupirtine or meclofenamic acid (MFA). The frequency of Ca2+-oscillations in SMC contained within bladder tissue sheets was increased by XE991. Outward currents in dispersed bladder SMC, recorded under conditions where BK and KATP currents were minimal, were significantly reduced by XE991, linopirdine, or chromanol, and enhanced by flupirtine or MFA. XE991 depolarized the cell membrane and could evoke transient depolarizations in quiescent cells. Flupirtine (20 μM) hyperpolarized the cell membrane with a simultaneous cessation of any spontaneous electrical activity.Conclusions and ImplicationsThese novel findings reveal the role of KCNQ currents in the regulation of the resting membrane potential of detrusor SMC and their important physiological function in the control of spontaneous contractility in the guinea pig bladder.

Principles of Cardiac Electric Propagation and Their Implications for Re-entrant Arrhythmias

The study of clinical electrophysiology essentially comprises examining how electric excitation develops and spreads through the millions of cells that constitute the heart. Given the enormous number of cells in a human heart, there is an extremely large number of possible ways that the heart can behave. We encounter rhythms across the spectrum from the organized and orderly behavior of sinus rhythm through repetitive continuous excitation (via reentry) in structurally defined circuits like atrial flutter and, finally, the complex, dynamic, and disorganized behavior of fibrillation. Despite these myriad possibilities, one can apply a basic understanding of the principles of propagation to predict how cardiac tissue will behave under varied circumstances and in response to various manipulations. In this article, we review the principles of propagation and how these can be used to understand reentry of all degrees of complexity. We use these principles to explain the mechanisms by which antiarrhythmic medications and ablation can terminate and prevent reentry. This article is not intended to be an exhaustive description of the physiology of cardiac propagation, rather, it is meant to capture the essence of propagation with sufficient detail to provide an intuitive feel for the interplay of the physiological features relevant to propagation. The figures and videos used in this article were created using a computational model of cardiac propagation (VisibleEP LLC, Colchester, VT). It is a hybrid between a physics-based and cellular automaton model. The model incorporates the fundamental features of propagation without modeling individual ion channels.1 The model manifests several relevant emergent properties, for example, electrotonic interactions, restitution of action potential duration, and conduction velocity as well as source–sink balance–dependent propagation. ### Cell Excitation A cell becomes excited when the balance of inward and outward currents passes a critical point after which inward currents exceed outward and an action potential ensues. …

Collagen fiber alignment and maximum principal strain in the glenohumeral capsule predict location of failure during uniaxial extension

The glenohumeral joint is frequently dislocated resulting in injury to the glenohumeral capsule. Repair techniques that focus on restoring the capsule after dislocation to re-establish its stabilizing function could benefit from predictions of the location of failure in this continuous sheet of tissue with a random collagen fiber alignment in the unloaded state. Therefore, the objective of this study was to determine the collagen fiber alignment and maximum principal strain in all regions of the capsule during uniaxial extension to failure and to determine whether these parameters could predict the location of tissue failure. Collagen fiber alignment, quantified using a small-angle light-scattering device, and maximum principal strain in the capsule were determined at 5% increments of elongation until tissue failure. A contingency table analyzed with Fischer's exact test demonstrated that peak collagen fiber alignment, represented by the normalized orientation index (p < 0.001) and maximum principal strain (p < 0.001), is significant in predicting location of failure. The direct correlation between the maximum principal strain and collagen fiber alignment measured prior to failure to the location of tissue failure suggests these parameters can be used as a predictive tool to help locate the areas of the glenohumeral capsule that are susceptible to failure. In the future, changes in collagen fiber alignment following injury could be used to develop a constitutive model for injured capsular tissue.

Material and structural properties of fin whale (Balaenoptera physalus) Zwischensubstanz

The oral anatomy of the fin whale (Balaenoptera physalus) consists of several major structures crucial to its engulfment method of feeding, such as stiff keratinized baleen plates, a large flaccid tongue, and a prominent vomer. One under-documented part of this anatomy is the cream white Zwischensubstanz that holds the baleen plates to the rostrum at their dorsal base. The mechanical and structural properties of Zwischensubstanz play a key role in baleen plate dynamics and, on the grand scale, contribute to baleen whales' filtration efficiency and attainment of large body size. Compression and tensile tests on the Zwischensubstanz sampled from an 18 m fin whale showed that this material unexpectedly exhibits linear isotropic behaviour with Elastic Modulus of 2.56 ± 0.60 MPa and hysteresis of 0.44 ± 0.02 in compression despite apparent unidirectional growth. Acting similar to a soft rubber, the Zwischensubstanz absorbs and dissipates the enormous forces acting on baleen plates during engulfment feeding while maintaining spacing between the plates to maximize filtration efficiency. Microscopic analysis provided images of connective tissue papillae penetrating the base of the Zwischensubstanz and developing within it to emerge as fully formed, keratinized baleen plates. The plates develop from the papillae and a connective tissue sheet within the 5-7 cm deep Zwischensubstanz. The Zwischensubstanz provides a keratin matrix of concentrically oriented fibers around each papilla forming the hard baleen plates and frayed fringes used for filter feeding. During this formation, the Zwischensubstanz remains unchanged and appears to slough away to allow the baleen plate to grow unhindered.

Boundary layers and the distribution of membrane forces predicted by the mechanical bidomain model

The mechanical bidomain model is a mathematical description of the elastic properties of cardiac tissue. The unique feature of the bidomain model is that it is a macroscopic continuum representation of tissue that nevertheless accounts for the intracellular and extracellular spaces individually, thereby focusing on mechanical forces arising across the cell membrane. In this paper, the mechanical bidomain model describes a two-dimensional sheet of cardiac tissue undergoing a uniform active tension. At the boundary, the tissue sheet is free to move. Analytical solutions are found for the intracellular and extracellular displacements and pressures. The model predicts that membrane forces, which may be responsible for phenomena such as mechanotransduction and remodeling, are large near the tissue boundary, and fall off rapidly with distance from the boundary.

Soft sheets of fibrillar bone from a fossil of the supraorbital horn of the dinosaur Triceratops horridus

Soft fibrillar bone tissues were obtained from a supraorbital horn of Triceratops horridus collected at the Hell Creek Formation in Montana, USA. Soft material was present in pre and post-decalcified bone. Horn material yielded numerous small sheets of lamellar bone matrix. This matrix possessed visible microstructures consistent with lamellar bone osteocytes. Some sheets of soft tissue had multiple layers of intact tissues with osteocyte-like structures featuring filipodial-like interconnections and secondary branching. Both oblate and stellate types of osteocyte-like cells were present in sheets of soft tissues and exhibited organelle-like microstructures. SEM analysis yielded osteocyte-like cells featuring filipodial extensions of 18–20μm in length. Filipodial extensions were delicate and showed no evidence of any permineralization or crystallization artifact and therefore were interpreted to be soft. This is the first report of sheets of soft tissues from Triceratops horn bearing layers of osteocytes, and extends the range and type of dinosaur specimens known to contain non-fossilized material in bone matrix.

Cell Differentiation of Pluripotent Tissue Sheets Immobilized on Supported Membranes Displaying Cadherin-11

Investigating cohesive tissue sheets in controlled cultures still poses a challenge since the complex intercellular interactions are difficult to mimic in in vitro models. We used supported lipid membranes functionalized by the adhesive part of the extracellular domain of the cell adhesion molecule cadherin-11 for the immobilization of pluripotent tissue sheets, the animal cap isolated from Xenopus laevis blastula stage embryos. Cadherin-11 was bound via histidine tag to lipid membranes with chelator head groups. In the first step, quantitative functionalization of the membranes with cadherin-11 was confirmed by quartz crystal microbalance and high energy specular X-ray reflectivity. In the next step, animal cap tissue sheets induced to neural crest cell fate were cultured on the membranes functionalized with cadherin-11. The adhesion of cells within the cohesive tissue was significantly dependent on changes in lateral densities of cadherin-11. The formation of filopodia and lamellipodia in the cohesive tissue verified the viability and sustainability of the culture over several hours. The expression of the transcription factor slug in externally induced tissue demonstrated the applicability of lipid membranes displaying adhesive molecules for controlled differentiation of cohesive pluripotent tissue sheets.

Improved Tissue Culture Conditions for Engineered Skeletal Muscle Sheets

The potential clinical utility of engineered muscle is currently restricted by limited in vitro capacity of expanded muscle precursor cells to fuse and form mature myofibers. The purpose of this study was to use isotropic skeletal muscle sheets to explore the impact of (1) fibroblast coculture and (2) fibroblast-conditioned media (fCM) on in vitro myogenesis. Muscle sheets were prepared by seeding varying ratios of skeletal myoblasts and fibroblasts on a biomimetic substrate and culturing the resulting tissue in either control media or fCM. Muscle sheets were prepared from two cell subpopulations, (1) C2C12 and NOR-10 and (2) primary neonatal rat skeletal muscle cells (nSKM). In C2C12/Nor-10 muscle sheets fCM conferred a myogenic advantage early in culture; at D1 a statistically significant 3.12 ± 0.8-fold increase in myofiber density was observed with fCM. A high purity satellite cell population was collected from an initially mixed population of nSKMs via cell sorting for positive α7-integrin expression. On D6, tissue sheets with low fibroblast concentrations (0 & 10%) cultured in fCM had increased average myofiber density (4.8 ± 0.2 myofibers/field) compared to tissue sheets with high fibroblast concentrations (50%) cultured in control media (1.0 ± 0.1 myofibers/field). Additionally, fCM promoted longer, thicker myofibers with a mature phenotype.

Recent Advances in the Development of Tissue-engineered Vascular Media Made by Self-assembly

There is a lack of an optimal transplant material for small calibre blood vessels. This could be overcome by tissue engineering. The optimal construct is to be derived from autologous cells and present mechanical resistance comparable to the gold standard, autologous vessels such as the internal mammary artery or the saphenous vein. Our laboratory has developed the self-assembly approach to produce tissue sheets that can be rolled into such vessel substitutes. Over the years, many improvements have been made to the technique to facilitate smooth muscle cell culture and to produce vascular media substitutes with higher circumferential mechanical resistance.

Immunohistochemical characterization and functional identification of mammary gland telocytes in the self‐assembly of reconstituted breast cancer tissue in vitro

Telocyte (TC) as a special stromal cell exists in mammary gland and might play an important role in the balance of epithelium-stroma of mammary gland. Considering that different types of breast interstitial cells influence the development and progression of breast cancer, TCs may have its distinct role in this process. We here studied the roles of TCs in the self-assembly of reconstituted breast cancer tissue. We co-cultured primary isolated TCs and other breast stromal cells with breast cancer EMT-6 cells in collagen/Matrigel scaffolds to reconstitute breast cancer tissue in vitro. Using histology methods, we investigated the immunohistochemical characteristics and potential functions of TCs in reconstituted breast cancer tissue. TCs in primary mammary gland stromal cells with long and thin overlapping cytoplasmic processes, expressed c-kit/CD117, CD34 and vimentin in reconstitute breast cancer tissue. The transmission electron microscopy showed that the telocyte-like cells closely communicated with breast cancer cells as well as other stromal cells, and might serve as a bridge that directly linked the adjacent cells through membrane-to-membrane contact. Compared with cancer tissue sheets of EMT-6 alone, PCNA proliferation index analysis and TUNEL assay showed that TCs and other breast stromal cells facilitated the formation of typical nest structure, promoted the proliferation of breast cancer cells, and inhibited their apoptosis. In conclusion, we successfully reconstituted breast cancer tissue in vitro, and it seems to be attractive that TCs had potential functions in self-assembly of EMT-6/stromal cells reconstituted breast cancer tissue.