Biodegradable nanofiber coated human umbilical cord as nerve scaffold for sciatic nerve regeneration in albino Wistar rats.

BACKGROUND: Human umbilical cord (hUC) is encompassed by a mucoid connective tissue called Wharton's jelly (WJ), made of hyaluronic acid, collagen, and stromal cells to support the blood vessels of hUC. This study was aimed to determine the in vitro neuronal differentiation of WJ-derived mesenchymal stem cells (WJMSCs), and in vivo axonal regeneration potential of nanofiber coated human Wharton's jelly as a neuronal graft after sciatic nerve injury in immunosuppressed albino Wistar rats. MATERIALS AND METHODS: Wharton's jelly-derived mesenchymal stem cells could be differentiated to neuron-like cells by inducing with neuronic supplementing media. The test animal's axotomized nerves were implanted with trimmed human umbilical cord devoid of vascularity and nanocoated with electro-spun poly-l-lactic acid nanofibers. The control animals were bridged with native sciatic nerve reversed and sutured. Post-surgical functional recovery was studied by walking track, pinprick, muscle weight, and sweating quantification. At the end of the 4th week, the animals were euthanized, and magnetoneurography was performed. The explanted grafts were quantified by immunohistochemistry for immuno-rejection, neural scarring, neural adhesion axon regeneration, fibre diameter, myelin thickness, and G-ratio. The sciatic function index values were similar by walking track analysis for both the test and control groups. RESULTS: The animals had functional and sensation recovery by the end of 2 weeks. No mortality, signs of inflammation, and acute immune rejection were observed post-surgery. CONCLUSIONS: The hUCWJ devoid of vascular elements can be a perfect peripheral nerve graft, and we hypothesis that the cryopreserved hUC could be an ideal resource for axonal regeneration in the future.

Fabrication and Electrospinning of 3D Biodegradable Poly-l-Lactic Acid (PLLA) Nanofibers for Clinical Application.

Poly-L-lactic acid (PLLA) is a biodegradable synthetic polyester synthesized by polymerization or polycondensation. PLLA hydrolytically degrades into lactic acid, a biocompatible metabolic by-product, making it suitable for clinical applications. PLLA scaffolds or nanofibers have been used in various regenerative medicine and drug delivery applications. These scaffolds impart biocompatible properties of high surface area, hydrophobicity, native extracellular properties, and mechanical strength for an organ system. Moreover, PLLA nanofibers hold great promise as drug delivery systems, where fabrication parameters and drug-PLA compatibility greatly affect the drug release kinetics. In this chapter, we present the protocols to fabricate, electrospinning, and validation of 3D PLLA nanofibrous scaffolds for tissue engineering application and offer perspectives on their future use.

Use of Indigenous Decellularized Valved Xenograft Conduit for Double-Barrel Right Ventricular Outflow Tract Reconstruction: Nine-Year Follow-Up.

Over the last two decades, numerous conduit options and implantation techniques have been described for right ventricular outflow tract (RVOT) reconstruction in the management of tetralogy of Fallot (TOF) with hypoplastic pulmonary annulus. The limited availability of homografts and the cost factor have led us to explore the use of decellularized xenografts as an alternative. Here we present a nine-year follow-up of an adult patient with TOF with hypoplastic pulmonary annulus, who underwent reconstruction of the RVOT by the double-barrel technique, using a decellularized porcine pulmonary artery xenograft valved conduit.

Large-scale in-vitro expansion of RBCs from hematopoietic stem cells.

The quest for RBCs in transfusion medicine has prompted scientists to explore the large-scale expansion of human RBCs from various sources. The successful production of RBCs in the laboratory depends on the selection of potential cell source, optimized culture, bio-physiological parameters, clinically applicable culture media that yields a scalable, contamination-free, non-reactive, non-tumorogenic, stable and functional end product. The expansion protocol considering the in vivo factors involved in homeostasis can generate a cost-effective and readily available cell source for transfusion. This review paper discusses several approaches used to expand RBCs from various sources of stem cells.

Crosslinked acellular saphenous vein for small-diameter vascular graft.

OBJECTIVE: Patients with congenital and acquired heart diseases or arteriopathy require small-diameter vascular grafts for arterial reconstruction. Autologous veins are the most suitable graft, but when absent, an alternative is necessary. This work addresses the issue. BACKGROUND: Tissue-engineering efforts to create such grafts by modifications of acellular natural scaffolds are considered a promising area. METHODS: Homologous saphenous veins harvested from cadavers and organ donors were processed by decellularization with detergent and enzymatic digestion, followed by crosslinking by dye-mediated photooxidation. They were validated for acellularity, mechanical strength, and crosslink stability. In-vitro and in-vivo cytotoxicity and hemocompatibility studies were conducted. Collagen conformity was studied by Fourier transform infrared spectroscopy, and heat stability by differential scanning calorimetry. A limited large animal study was performed. RESULTS: The processing method delivered biocompatible, hemocompatible, effectively crosslinked grafts, with high heat stability of 126 , an enthalpy value of 183.5 J·g(-1), and collagen conformity close to that of the native vein. The mechanical strength was 250% better than the native vein. The presence of extracellular matrix proteins allowed the acellular vein to become a triple-layered vascular structure in the sheep venous system. CONCLUSION: Crosslinking after decellularization by the dye-mediated photooxidation method could be reproduced in any human vein to obtain a small-diameter vascular grafts.

Ischemic cardiac tissue conditioned media induced differentiation of human mesenchymal stem cells into early stage cardiomyocytes.

Mesenchymal stem cells (MSCs) are multipotent, can be easily expanded in culture and hence are an attractive therapeutic tool for cardiac repair. MSCs have tremendous potential to transdifferentiate to cardiac lineage both in vitro and in vivo. The present study examined the differentiation capacity of conditioned media derived from ischemic cardiac tissue on human MSCs. Human Bone marrow-derived MSCs after due characterization by immunocytochemistry and flow cytometry for MSC specific markers were induced by culture media derived from ischemic (n = 13) and non-ischemic (n = 18) human cardiac tissue. Parallel cultures were treated with 5-azacytidine (5-azaC), a potent cardiomyogen. MSCs induced with ischemic conditioned media formed myotube like structures, expressed sarcomeric Troponin I, alpha myosin heavy chain proteins and were positive for cardiac specific markers (Nkx2.5, human atrial natriuretic peptide, myosin light chain-2a, GATA-4) as was observed in 5-azaC treated cells. However, uninduced MSCs as well as those induced with non-ischemic cardiac conditioned media still maintained the fibroblast morphology even after 3 weeks post-induction. Transmission electron microscopic studies of cardiomyocyte-like cells derived from MSCs revealed presence of sarcomeric bands but failed to show gap junctions and intercalated discs as of adult cardiomyocytes. These findings demonstrate that ischemic cardiac conditioned media induces morphological and molecular changes in MSCs with cardiac features, but at a primitive stage. Proteomics analysis of the ischemic conditioned media revealed differential expression of three relevant proteins (C-type lectin superfamily member 13, Testis-specific chromodomain protein Y2 and ADP/ATP translocase 1), whose exact role in cardiac regeneration needs further analysis.

Nanofiber-reinforced biological conduit in cardiac surgery: preliminary report.

Several options are available for right ventricular outflow tract reconstruction, including commercially available bovine jugular vein and cryo-preserved homografts. Homograft non-availability and the problems of commercially available conduits led us to develop indigenously processed bovine jugular vein conduits with competent valves. They were made completely acellular and strengthened by non-conventional cross-linking without disturbing the extracellular matrix, which improved the luminal surface characteristics for hemocompatibility. Biocompatibility in vitro and in vivo, along with thermal stability, matrix stability, and mechanical strength have been evaluated. Sixty-nine patients received these conduits for right ventricular outflow tract reconstruction. Seven conduits dilated and 4 required replacement. To counteract dilatation, biodegradable polymeric nanofibers in various combinations and in isolation (collagen, polycaprolactone, polylactic acid) were characterized and used to reinforce the conduit circumferentially. Physical validation by mechanical testing, scanning electron microscopy, and in-vitro cytotoxicity was conducted. Thermal stability, spectroscopy studies of the polymer, and preclinical studies of the coated bovine jugular vein in animals are in progress. The feasibility studies have been completed, and the final polymer selection depends on evaluation of the functional superiority of the coated bovine jugular vein.