Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Development of biomaterial scaffold for nerve tissue engineering: Biomaterial mediated neural regeneration
Anuradha Subramanian, Uma Krishnan, Swaminathan Sethuraman
Journal of Biomedical Science , 2009, DOI: 10.1186/1423-0127-16-108
Abstract: The human brain is analogous to a black box of information and unraveling its mysteries is essential to understand its complex relationship with the various components of the peripheral and central nervous systems. This information is vital to probe the causes for various neural disorders and arrive at a plausible therapy for the treatment of ischemic, metabolic, congenital, or degenerative disorders of the central or peripheral nervous systems. Conventionally, autologous grafts are gold standards and have been used to treat neural defects [1-3]. However, autografts have limitations that include shortage of nerves since it is taken from the patient. Moreover, there is a mismatch of donor-site nerve size with the recipient site, neuroma formation and lack of functional recovery [4,5]. Allogenic grafts, which are isolated from cadavers, are not limited by supply but suffer from host-graft immune rejection [6]. To overcome immune rejection, several studies have been conducted to examine the potency of acellular nerve grafts [7,8]. However, as acellular nerve graft lacks viable cells, nerve regeneration and remodeling of extracellular matrix have been delayed [8]. The use of pre-degenerated nerve grafts having high matrix metalloproteinase (MMP) expression shows some potential as it degrades the inhibitory chondroitin sulphate and proteoglycans thereby retaining the ability to promote nerve regeneration even in the absence of cells [8,9].Recent advances in nanotechnology [10] and tissue engineering [11,12] have been found to cover a broad range of applications in regenerative medicine and offer the most effective strategy to repair neural defects. The major determinant in all tissue engineering research is to regulate the cell behavior and tissue progression through the development and design of synthetic extracellular matrix analogues of novel biomaterials to support three-dimensional cell culture and tissue regeneration. Ideal properties of a scaffold for nerve regene
Surface Modification of Poly(L-lactic acid) Nanofiber with Oligo(D-lactic acid) Bioactive-Peptide Conjugates for Peripheral Nerve Regeneration  [PDF]
Sachiro Kakinoki,Sho Uchida,Tomo Ehashi,Akira Murakami,Tetsuji Yamaoka
Polymers , 2011, DOI: 10.3390/polym3020820
Abstract: In some traumatic nerve injuries, autologous nerve grafting is the first choice for bridging the gap between the severed nerve ends. However, this therapeutic strategy has some disadvantages, including permanent loss of donor function and requirement of multiple surgeries. An attractive alternative to this therapeutic technique is the use of artificial nerve conduit. Poly (L-lactic acid) (PLLA) is widely used as a substrate for artificial nerve conduit because it is readily biodegradable, but it is not inherently biologically active. In this study, we developed a PLLA nanofibrous nerve conduit, modified with a conjugate of oligo (D-lactic acid) (ODLA) and the neurite outgrowth, thereby promoting peptide AG73 (RKRLQVQLSIRT) to improve nerve regeneration. PLA/ODLA-AG73 nanofibrous conduit was fabricated by electrospinning and then transplanted at the 10 mm gap of rat sciatic nerve. After six months, electrophysiological evaluation revealed that it achieved better functional reinnervation than silicone tube (used as a reference) or unmodified PLLA nanofibrous conduit.
Therapeutic approaches enhancing peripheral nerve regeneration  [PDF]
M. Egle De Stefano, Francesca Toni, Valerio D’ Orazi, Andrea Ortensi, Ada Maria Tata
Advances in Bioscience and Biotechnology (ABB) , 2013, DOI: 10.4236/abb.2013.46A008
Abstract: Peripheral nerve injury is a common occurrence and represents a major economic burden for society. The development of novel strategies to enhance peripheral nerve regeneration is, therefore, of great relevance. Conventional treatments include surgical repair of the damaged nerves for minor injuries, whereas autologous nerve grafts are required to recover longer interruptions. However, despite great surgical advances, functional recovery is often poor. Although it is well known that the peripheral nervous system has a greater regenerative capacity than the central nervous system and, considering the scientific advancements and knowledge in regenerative medicine, clinical applications appears still limited. This review provides an overview of the methodological approaches currently under study, aimed at enhancing peripheral nerve regeneration. In particular, tissue engineering, cell therapy and pharmacological approaches will be discussed.
Tissue Engineering Strategies in Ligament Regeneration
Caglar Yilgor,Pinar Yilgor Huri,Gazi Huri
Stem Cells International , 2012, DOI: 10.1155/2012/374676
Abstract: Ligaments are dense fibrous connective tissues that connect bones to other bones and their injuries are frequently encountered in the clinic. The current clinical approaches in ligament repair and regeneration are limited to autografts, as the gold standard, and allografts. Both of these techniques have their own drawbacks that limit the success in clinical setting; therefore, new strategies are being developed in order to be able to solve the current problems of ligament grafting. Tissue engineering is a novel promising technique that aims to solve these problems, by producing viable artificial ligament substitutes in the laboratory conditions with the potential of transplantation to the patients with a high success rate. Direct cell and/or growth factor injection to the defect site is another current approach aiming to enhance the repair process of the native tissue. This review summarizes the current approaches in ligament tissue engineering strategies including the use of scaffolds, their modification techniques, as well as the use of bioreactors to achieve enhanced regeneration rates, while also discussing the advances in growth factor and cell therapy applications towards obtaining enhanced ligament regeneration.
Aberrant regeneration of the third cranial nerve  [PDF]
UD Shrestha,S Adhikari
Nepalese Journal of Ophthalmology , 2012, DOI: 10.3126/nepjoph.v4i1.5872
Abstract: Background : Aberrant regeneration of the third cranial nerve is most commonly due to its damage by trauma. Case : A ten-month old child presented with the history of a fall from a four-storey building. She developed traumatic third nerve palsy and eventually the clinical features of aberrant regeneration of the third cranial nerve. The adduction of the eye improved over time. She was advised for patching for the strabismic amblyopia as well. Conclusion : Traumatic third nerve palsy may result in aberrant regeneration of the third cranial nerve. In younger patients, motility of the eye in different gazes may improve over time. DOI: http://dx.doi.org/10.3126/nepjoph.v4i1.5872 NEPJOPH 2012; 4(1): 176-178
International symposium on peripheral nerve repair and regeneration and 2nd club Brunelli meeting
Mehmet Turgut, Stefano Geuna
Journal of Brachial Plexus and Peripheral Nerve Injury , 2010, DOI: 10.1186/1749-7221-5-5
Abstract: Interest in the study of peripheral nerve repair and regeneration has increased significantly over the last twenty years since, while in the past most nerve traumas and diseases were not surgically treated, today the number of nerve reconstructions performed is progressively increasing due to the continuous improvement in surgical technology and to the spread of microsurgical skills among surgeons worldwide. Unfortunately, in spite of the impressive technical advancements in nerve reconstruction, complete recovery and normalization of nerve function almost never occur and the clinical outcome is often poor. It can be thus expected that the increasing number of patients receiving nerve surgery will represent an important stimulus for more research in this scientific field.In line with this growing interest, the International Symposium "Peripheral Nerve Repair and Regeneration and 2nd Club Burnelli Meeting" was held at the Department of Animal and Human Biology of the University of Turin, Italy, on December 4-5, 2009 (figure 1) [1]. The topics covered along the symposium were: neurobiology of peripheral nerve regeneration, glial cells, tissue engineering, innovative strategies for promoting nerve regeneration, biomaterials and artificial conduits for nerve reconstruction, and clinical applications, such as tubulization and end-to-side neurorrhaphy. The international and multidisciplinary panel of papers addressed, from many points of view, the current knowledge on nerve repair and regeneration, from the basic mechanisms to the perspectives for defining innovative treatment strategies for improving nerve recovery in human and veterinary medicine. Both basic and clinical scientists with different background (including neurobiologists, neuroanatomists, neurologists, biomaterial engineers, neurosurgeons, plastic and reconstructive surgeons, hand surgeons and orthopedists) attended to the Symposium and a total of 47 oral talks were given by lecturers coming from various co
Thyroid Hormones and Peripheral Nerve Regeneration  [PDF]
Ioannis D. Papakostas,George A. Macheras
Journal of Thyroid Research , 2013, DOI: 10.1155/2013/648395
Abstract: Peripheral nerve regeneration is a unique process in which cellular rather than tissue response is involved. Depending on the extent and proximity of the lesion and the age and type of the neuronal soma, the cell body may either initiate a reparative response or may die. Microsurgical intervention may alter the prognosis after a peripheral nerve injury but to a certain extent. By altering the biochemical microenvironment of the neuron, we can increase the proportion of neurons that survive the injury and initiate the reparative response. Thyroid hormone critically regulates tissue growth and differentiation and plays a crucial role during organ development. Furthermore, recent research has provided new insight into thyroid hormone cellular action. Thyroid hormone regulates stress response intracellular signaling and targets molecules important for cytoskeletal stability and cell integrity. Changes in thyroid hormone signaling occur in nerve and other tissues, with important physiological consequences. The interest in thyroid hormone in the context of nerve regeneration has recently been revived. 1. Introduction Thyroid hormones are essential for the development and maturation of the central nervous system. There is a period in brain development in which the euthyroid status is a prerequisite for normal development. Thyroid hormones promote morphogenesis and function in various areas of the brain. The molecular basis of the thyroid dependent brain development is not yet clarified [1]. Among other processes, defects in myelination, delays in the development of the dendritic tree, decreased number of glial cells, and axo-dendritic synapses have all been described in hypothyroid newborn rats. Peripheral nerve injuries are very common in the clinical setting [2]. These injuries are very debilitating, commonly affecting the younger more productive portion of the population. Microsurgical techniques to restore nerve continuity have reached their limits, and further surgical advancements in the field of peripheral nerve surgery are unlikely to improve the prognosis. A different approach based on the cellular and molecular aspects of regeneration should be followed [3]. This approach is justified by the fact that peripheral nerve injuries are in reality cellular, rather than tissue injuries. It is the long axon of the neuron that has been injured. In response, the cell body adapts in an effort to restore the cellular volume and function. Before adaptation the neuron should first survive from the index event. Apoptosis can be the fate of a large proportion of
Effect of Erythropoietin on Peripheral Nerve Regeneration
Journal of Neurological Sciences , 2010,
Abstract: The aim of this study was to identify the effect of erythropoietin (EPO) on a sciatic nerve injury model. The effect of single or repeated doses was also determined. Twenty-one Wistar rats were anesthetised and the sciatic nerve was transected 1 cm above the trifurcation and the nerve was repaired with four epineural 10/0 nylon sutures placed at 90 degrees intervals under microscope magnification.The rats were divided into 4 groups as follows: the sham,the saline, the single dose EPO and the multiple dose EPO. The skin was incised and closed and no treatment was given in sham group. In the saline group, 1 mL saline was given intraperitoneally; in the single EPO group, 5000 U/kg EPO was given intraperitoneally immediately after the procedure. In the multiple EPO group, 5000 U/kg EPO was given after the procedure and the same dose was repeated after the 1st, 2nd, 3rd and 4th weeks. Functional recovery was evaluated by static sciatic functional index(SSI).Single EPO group had greater myofibril size, axon number, diameter, and ratio M than the saline group. The multiple EPO treatment was not found to be more effective than single EPO treatment. However, no significant difference was found between the single EPO, multiple EPO, and saline groups based on the 3rd and 4th postoperative month SSI scores. Thus, EPO treatment increased axonal regeneration in our study. However, repeated dose therapy was not found to be more effective than single dose therapy. The optimum dose and duration should be researched in further studies.
Chitosan-Based Macromolecular Biomaterials for the Regeneration of Chondroskeletal and Nerve Tissue  [PDF]
Giulio D. Guerra,Niccoletta Barbani,Mariacristina Gagliardi,Elisabetta Rosellini,Caterina Cristallini
International Journal of Carbohydrate Chemistry , 2011, DOI: 10.1155/2011/303708
Abstract: The use of materials, containing the biocompatible and bioresorbable biopolymer poly( )-2-amino-2-deoxy- -D-glucan, containing some N-acetyl-glucosamine units (chitosan, CHI) and/or its derivatives, to fabricate devices for the regeneration of bone, cartilage and nerve tissue, was reviewed. The CHI-containing devices, to be used for bone and cartilage regeneration and healing, were tested mainly for in vitro cell adhesion and proliferation and for insertion into animals; only the use of CHI in dental surgery has reached the clinical application. Regarding the nerve tissue, only a surgical repair of a 35?mm-long nerve defect in the median nerve of the right arm at elbow level with an artificial nerve graft, comprising an outer microporous conduit of CHI and internal oriented filaments of poly(glycolic acid), was reported. As a consequence, although many positive results have been obtained, much work must still be made, especially for the passage from the experimentation of the CHI-based devices, in vitro and in animals, to their clinical application. 1. Introduction Chitosan (CHI) is a poly( )-2-amino-2-deoxy- -D-glucan, containing some N-acetyl-glucosamine units (Figure 1), obtained by partial deacetylation of chitin, the main component of the exoskeleton of crustaceans, and it is generally considered as biocompatible and biodegradable [1, 2]; chitin and CHI are the most abundant polysaccharides among those containing amino sugars [3]. CHI was used some years ago, by the authors’ group, as a template for the polymerization of acrylic acid and sodium 4-styrenesulfonate [4]; the polyelectrolyte complex obtained with the first monomer showed a good cytocompatibility, while that with the second one seemed to influence negatively the cell proliferation [5]. Very many studies have been done on CHI and its derivatives as materials for the fabrication of scaffolds, used for tissue engineering and regeneration. The early studies about the possibility of using CHI and its derivatives in the food and biomedical sciences sand industries regarded mainly the immobilization of enzymes on the polysaccharide [6, 7]. The results obtained in this field up to 1980 were the argument of a review by A. Muzzarelli [3]. Another interesting argument of these early studies regarded the chelating ability of CHI towards metal cations [8–10], which was found later to facilitate the tissue mineralization in tooth implantation [11]; furthermore, it was proposed more recently that the CHI-metal interaction modes might be involved in the controlled bioactivity of CHI [12]. In 2005, R.
A Biosynthetic Nerve Guide Conduit Based on Silk/SWNT/Fibronectin Nanocomposite for Peripheral Nerve Regeneration  [PDF]
Fatemeh Mottaghitalab, Mehdi Farokhi, Arash Zaminy, Mehrdad Kokabi, Masoud Soleimani, Fereshteh Mirahmadi, Mohammad Ali Shokrgozar, Majid Sadeghizadeh
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0074417
Abstract: As a contribution to the functionality of nerve guide conduits (NGCs) in nerve tissue engineering, here we report a conduit processing technique through introduction and evaluation of topographical, physical and chemical cues. Porous structure of NGCs based on freeze-dried silk/single walled carbon nanotubes (SF/SWNTs) has shown a uniform chemical and physical structure with suitable electrical conductivity. Moreover, fibronectin (FN) containing nanofibers within the structure of SF/SWNT conduits produced through electrospinning process have shown aligned fashion with appropriate porosity and diameter. Moreover, fibronectin remained its bioactivity and influenced the adhesion and growth of U373 cell lines. The conduits were then implanted to 10 mm left sciatic nerve defects in rats. The histological assessment has shown that nerve regeneration has taken places in proximal region of implanted nerve after 5 weeks following surgery. Furthermore, nerve conduction velocities (NCV) and more myelinated axons were observed in SF/SWNT and SF/SWNT/FN groups after 5 weeks post implantation, indicating a functional recovery for the injured nerves. With immunohistochemistry, the higher S-100 expression of Schwann cells in SF/SWNT/FN conduits in comparison to other groups was confirmed. In conclusion, an oriented conduit of biocompatible SF/SWNT/FN has been fabricated with acceptable structure that is particularly applicable in nerve grafts.
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.