A greater supply of tendinous tissue can be obtained through tissue engineering technology with increasing application of adult stem cells. It is well known that adipose-derived stem cells (ADSCs), found in abundance in adipose tissue, have the same differentiating capacity as mesenchymal stem cells yet have the advantage of being easily isolated. In the present study, we combined the great facility of ADSCs to differentiate with the application of an external mechanical stimulus to successfully create an in vitro reconstructed tendonlike structure with a microcapillary network.
Nociceptive pain is one of the most common types of pain that originates from an injury involving nociceptors. Approximately 60% of the knee joint innervations are classified as nociceptive. The specific biological mechanism underlying the regulation of nociceptors is relevant for the treatment of symptoms affecting the knee joint. Intra-articular administration of exogenous hyaluronic acid (HA) in patients with osteoarthritis (OA) appears to be particularly effective in reducing pain and improving patient function.
???? ?Coverage of large skin defects, especially following tumor resection and in patients who are not good candidates for procedures requiring general anesthesia, may require a staged procedure. The use of dermal substitutes to cover the defect until autologous grafting can be performed has been described. Hyaluronic acid biological dressings (HABD) also have been used for the temporary coverage of partial- to full-thickness posttraumatic or postsurgical wounds. An 82-year-old man with cardiopathy presented with an 8 cm x 4 cm ulcerated squamous cell carcinoma on his forehead. Following surgical removal under local anesthesia, the 12 cm x 8 cm defect was covered with HABD, which was removed immediately before the scheduled surgical closure (21 days later). At that time, well-vascularized granulation tissue completely covered the bone and an autologous skin graft was applied. Punch biopsy results obtained 4 weeks after surgery showed dressing remnants in the dermis and confirmed the graft was totally integrated with the surrounding tissues; there was no evidence of hypertrophy or excessive scarring. In this patient, the staged procedure provided an excellent alternative to a complex surgical procedure. Use of the biological dressing required only a weekly wound and dressing assessment and the cosmetic result was good without evidence of a recurrence at the 2-year follow-up. Studies to ascertain the efficacy and effectiveness of this dressing for the temporary coverage of soft tissue defects are needed.
Alström Syndrome (ALMS) is a rare genetic disorder (483 living cases), characterized by many clinical manifestations, including blindness, obesity, type 2 diabetes and cardiomyopathy. ALMS is caused by mutations in the ALMS1 gene, encoding for a large protein with implicated roles in ciliary function, cellular quiescence and intracellular transport. Patients with ALMS have extensive fibrosis in nearly all tissues resulting in a progressive organ failure which is often the ultimate cause of death. To focus on the role of ALMS1 mutations in the generation and maintenance of this pathological fibrosis, we performed gene expression analysis, ultrastructural characterization and functional assays in 4 dermal fibroblast cultures from ALMS patients. Using a genome-wide gene expression analysis we found alterations in genes belonging to specific categories (cell cycle, extracellular matrix (ECM) and fibrosis, cellular architecture/motility and apoptosis). ALMS fibroblasts display cytoskeleton abnormalities and migration impairment, up-regulate the expression and production of collagens and despite the increase in the cell cycle length are more resistant to apoptosis. Therefore ALMS1-deficient fibroblasts showed a constitutively activated myofibroblast phenotype even if they do not derive from a fibrotic lesion. Our results support a genetic basis for the fibrosis observed in ALMS and show that both an excessive ECM production and a failure to eliminate myofibroblasts are key mechanisms. Furthermore, our findings suggest new roles for ALMS1 in both intra- and extra-cellular events which are essential not only for the normal cellular function but also for cell-cell and ECM-cell interactions.
The objective of this preliminary study was to develop a reabsorbable vascular patch that did not require in vitro cell or biochemical preconditioning for vascular wall repair. Patches were composed only of hyaluronic acid (HA). Twenty male Wistar rats weighing 250-350 g were used. The abdominal aorta was exposed and isolated. A rectangular breach (1 mm × 5 mm) was made on vessel wall and arterial defect was repaired with HA made patch. Performance was assessed at 1, 2, 4, 8, and 16 weeks after surgery by histology and immunohistochemistry. Extracellular matrix components were evaluated by molecular biological methods. After 16 weeks, the biomaterial was almost completely degraded and replaced by a neoartery wall composed of endothelial cells, smooth muscle cells, collagen, and elastin fibers organized in layers. In conclusion, HA patches provide a provisional three-dimensional support to interact with cells for the control of their function, guiding the spatially and temporally multicellular processes of artery regeneration.
In the last few years, adipose tissue, which has been largely ignored by anatomists and physicians for centuries, has found new brightness thanks to the stem cells contained within. These adipose derived stem cells (ADSC) have the same characteristics of the mesenchymal stem cells (MSC) residing in bone marrow. They have the same cell surface markers and are capable of differentiating into the same cell types, including osteoblasts, chondrocytes, myoblasts, adipocytes, and neuron-like cells. Adipose tissue is ubiquitous and uniquely expandable. Most patients possess excess fat that can be harvested, making adipose tissue the ideal large-scale source for research on clinical applications. In this review focused on the neural potential of adipose-derived stem cells. Current strategies for their isolation, differentiation, and in vitro characterization, as well as their latest in vivo applications for neurological disorders or injury repair, were discussed.
The ideal bioartificial liver should be designed to reproduce as nearly as possible in vitro the habitat that hepatic cells find in vivo. In the present work, we investigated the in vitro perfusion condition with a view to improving the hepatic differentiation of pluripotent human liver stem cells (HLSCs) from adult liver. Tissue engineering strategies based on the cocultivation of HLSCs with hepatic stellate cells (ITO) and with several combinations of medium were applied to improve viability and differentiation. A mathematical model estimated the best flow rate for perfused cultures lasting up to 7 days. Morphological and functional assays were performed. Morphological analyses confirmed that a flow of perfusion medium (assured by the bioreactor system) enabled the in vitro organization of the cells into liver clusters even in the deeper levels of the sponge. Our results showed that, when cocultured with ITO using stem cell medium, HLSCs synthesized a large amount of albumin and the MTT test confirmed an improvement in cell proliferation. In conclusion, this study shows that our in vitro cell conditions promote the formation of clusters of HLSCs and enhance the functional differentiation into a mature hepatic population.
Small is beautiful - this should be the slogan of nanoscientists. Indeed, working with particles less than 100 nm in size, nanotechnology is on the verge of providing a host of new materials and approaches, revolutionizing applied medicine. The obvious potential of nanotechnology has attracted considerable investment from governments and industry hoping to drive its economic development. Several areas of medical care already benefit from the advantages that nanotechnology provides and its application in wound healing will be reviewed in this article.
A significant amount of recent interest has been focused on the possibility that adult human stem cells are a realistic therapeutic alternative to embryonic stem cells. Multipotent stem cells that have characteristics reminiscent of embryonic neural crest stem cells have been isolated from several postnatal tissues, including skin, gut, dental pulp and the heart, and are potentially useful for research and therapeutic purposes. However, their neurogenic potential, including their ability to produce electrophysiologically active neurons, is largely unexplored. In the present work, we investigated this issue with regard to skin-derived precursors (SKPs) and adipose-derived stem cells (ADSc)
OBJECTIVE: In recent years, research on stem cells has been focused on the development of personalized cell-based therapies. Owing to their homing properties, adult human stem cells are a promising source of autologous cells to be used as therapeutic vehicles. Multiple potential sources for clinically useful stem and progenitor cells have been identified, including autologous and allogenic embryonic, fetal and adult somatic cells from neural, adipose and mesenchymal tissue. In the present report, we describe a simple protocol to obtain an enriched culture of adult stem cells organized in neurospheres from two post-natal tissues: skin and adipose tissue. METHODS: Adult stem cells isolated from skin and adipose tissue derived from the same adult donor were amplified under varying conditions related to the coating of the chamber slide and the presence of serum and/or growth factors, such as with EGF and FGF2. Neurospheres were then expanded and evaluated in terms of proliferation and gene expression. RESULTS: Adipose and skin derived neurospheres were comparable in size, quantity of cells and genes expressed. Cells from both types of tissue grew optimally without slide coating, in the presence of serum and with the combined addition of FGF2 and EGF. DISCUSSION: We describe a method for isolating and improving a population of multipotent adult precursor cells from the two most accessible adult tissue sources: skin and adipose tissue. This autologous adult stem cell population could be used for cell replacement or cell therapies.
Tissue engineering is a multidisciplinary field focused on in vitro reconstruction of mammalian tissues. In order to allow a similar three-dimensional organization of in vitro cultured cells, biocompatible scaffolds are needed. This need has provided immense momentum for research on "smart scaffolds" for use in cell culture. One of the most promising materials for tissue engineering and regenerative medicine is a hyaluronan derivative: a benzyl ester of hyaluronan (HYAFF). HYAFF can be processed to obtain several types of devices such as tubes, membranes, non-woven fabrics, gauzes, and sponges. All these scaffolds are highly biocompatible. In the human body they do not elicit any adverse reactions and are resorbed by the host tissues. Human hepatocytes, dermal fibroblasts and keratinocytes, chondrocytes, Schwann cells, bone marrow derived mesenchymal stem cells and adipose tissue derived mesenchymal stem cells have been successfully cultured in these meshes. The same scaffolds, in tube meshes, has been applied for vascular tissue engineering that has emerged as a promising technology for the design of an ideal, responsive, living conduit with properties similar to that of native tissue.
In this study, the stability and biocompatibility of methacrylated gellan gum hydrogels, obtained either by ionic- (iGG-MA) or photo-crosslinking (phGG-MA), were evaluated in vitro and in vivo. Size exclusion chromatography analysis of the methacrylated gellan gum (GG-MA) powder revealed that molecular weight is lower as compared to the non-modified material, i.e., low acyl gellan gum. The water uptake and swelling of iGG-MA and phGG-MA hydrogels were investigated in phosphate-buffered saline solution (pH 7.4). The biocompatibility of the hydrogels was firstly evaluated by producing cell-laden hydrogels. The in vitro cells encapsulation study showed that lung fibroblast cells (L929 cells) and human intervertebral disc (hIVD) cells are viable when cultured within both hydrogels, up to 21 days of culturing. The iGG-MA and phGG-MA hydrogels were also subcutaneously implanted in Lewis rats for 10 and 18 days. Tissue response to the hydrogels implantation was determined by histological analysis (haematoxylin-eosin staining). A thin fibrous capsule was observed around the implanted hydrogels. No necrosis, calcification, and acute inflammatory reaction were observed. The results presented in this study demonstrate that iGG-MA and phGG-MA hydrogels are stable in vitro and in vivo, support L929 and hIVD cells encapsulation and viability, and were found to be well-tolerated and non-toxic in vivo.
The aim of this study was to compare the effects of native hyaluronan (HA) with that of its hexadecylamide derivative (HYADD) on proliferation of fibroblast-like synoviocytes (FLS) and chondrocytes. The production of inflammatory and anti-inflammatory cytokines was also analyzed in FLS cultures. The proliferation of osteoarthritis (OA) chondrocytes was enhanced when cells were treated with 0.5-1.5 mg mL(-1) of HA or HYADD®4-G. This effect was completely suppressed by the anti-CD44 antibody. At 0.5 to 1 mg mL(-1) , HA and HYADD®4-G did not influence the proliferation of normal or pathological FLS; however, at the higher concentration (1.5 mg mL(-1) ), HYADD®4-G did significantly inhibit cell proliferation. As to effects on inflammation, a significant increase in the expression of the IL-10 gene was observed when FLS were pretreated with tumor necrosis factor alpha and then cultured in the presence of 0.5 mg mL(-1) HYADD® 4-G or HA. The effects of HA derivatives on FLS proliferation and production of anti-inflammatory cytokines indicate that they may be of therapeutic benefit in OA. The longer residence time in the joint cavity, the increased viscoelasticity, and the anti-inflammatory potential of HYADD®4-G make it a better candidate than native HA for OA therapy.
An observational study was carried out at the Plastic and Reconstructive Surgery Unit of the University of Pavia - Salvatore Maugeri Research and Care Institute, Pavia, Italy, to assess the clinical and histological long-term outcomes of autologous skin grafting of fresh surgical wounds following previous repair with a hyaluronic acid three-dimensional scaffold (Hyalomatrix®). Eleven fresh wounds from surgical release of retracted scars were enrolled in this study. A stable skin-like tissue cover was observed in all of the treated wounds in an average 1 months time; at the end of this study, after an average of 12 months time, all of the reconstructed areas were pliable and stable, although an average retraction rate of 51·62% was showed. Histological observation and immunohistochemical analysis displayed integration of the graft within the surrounding tissues. A regenerated dermis with an extracellular matrix rich in type I collagen and elastic fibres and with reduced type III collagen rate was observed. The epidermis and dermoepidermal junction featured a normal appearance with well-structured dermal papillae, too. Although the histological features would suggest regeneration of a skin-like tissue, with a good dermis and no signs of scarring, the clinical problem of secondary contracture is still unsolved.
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