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Ramesh B.,Frontier Lifeline Pvt. Ltd. | Mathapati S.,Frontier Lifeline Pvt. Ltd. | Galla S.,Frontier Lifeline Pvt. Ltd. | Cherian K.M.,Frontier Lifeline Pvt. Ltd. | Guhathakurta S.,Indian Institute of Technology Madras
Asian Cardiovascular and Thoracic Annals | Year: 2013

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 °C, 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. © 2012 The Author(s).

Mathapati S.,Indian Institute of Technology Madras | Mathapati S.,Frontier Lifeline Pvt. Ltd. | Arumugam S.B.,Frontier Lifeline Pvt. Ltd. | Verma R.S.,Indian Institute of Technology Madras
Acta Histochemica | Year: 2010

Inflammation is one of the important contributing factors for the development of atherosclerosis and heart disease. Inflammation leads to the mobilization of various cells in developing atherosclerotic plaque and simultaneously triggers the up-regulation of various cytokine secretions from effector cells. To understand early molecular events during atherosclerosis we developed a rabbit model in which male New Zealand White rabbits were fed high cholesterol diets for 12 weeks. Total cholesterol (TC), triglycerides (TG), low density lipoprotein-cholesterol (LDL-C) and high sensitivity C-reactive protein (hs-CRP) were significantly increased in the high cholesterol diet group when compared to the control group during the experimental period (P<0.05). In parallel, the immunolocalization of CD40, MMP9, S100, CD68, α-smooth muscle actin and von Willebrand factor (vWF) in developing atherosclerotic plaque of the aorta and carotid artery was increased in comparison with the controls fed with a regular diet (P<0.05). From the present study, we conclude that a high cholesterol diet up-regulates CD68 and CD40, which may play a possible role in the remodelling and destabilization of the atherosclerotic plaque of arteries with the up-regulation of MMP9 and hsCRP. © 2009 Elsevier GmbH.

Tekkatte C.,Frontier Lifeline Pvt. Ltd. | Gunasingh G.P.,Frontier Lifeline Pvt. Ltd. | Cherian K.M.,Frontier Lifeline Pvt. Ltd. | Sankaranarayanan K.,Anna University
Stem Cells International | Year: 2011

Cellular therapy is reaching a pinnacle with an understanding of the potential of human mesenchymal stem cells (hMSCs) to regenerate damaged tissue in the body. The limited numbers of these hMSCs in currently identified sources, like bone marrow, adipose tissue, and so forth, bring forth the need for their in vitro culture/expansion. However, the extensive usage of supplements containing xenogeneic components in the expansion-media might pose a risk to the post-transplantation safety of patients. This warrants the necessity to identify and develop chemically defined or humanized supplements which would make in vitro cultured/processed cells relatively safer for transplantation in regenerative medicine. In this paper, we outline the various caveats associated with conventionally used supplements of xenogenic origin and also portray the possible alternatives/additives which could one day herald the dawn of a new era in the translation of in vitro cultured cells to therapeutic interventions. Copyright © 2011 Chandana Tekkatte et al.

Mathapati S.,Frontier Lifeline Pvt. Ltd. | Mathapati S.,Indian Institute of Technology Madras | Verma R.S.,Indian Institute of Technology Madras | Cherian K.M.,Frontier Lifeline Pvt. Ltd. | Guhathakurta S.,Frontier Lifeline Pvt. Ltd.
Interactive Cardiovascular and Thoracic Surgery | Year: 2011

Acellular tissue-engineered (ATE) xenografts and homografts are used in clinical cardiovascular surgery. The present study examined the specific role of carbohydrate antigen (a-Gal and T-antigen) in immune response after decellularisation in tissue-engineered xenografts (porcine pulmonary artery and bovine jugular vein). An enzyme-linked immunosorbent assay (ELISA) was used to ascertain whether implantation of bioprostheses, ATE xenografts and mechanical valve replacement result in augmentation of anti-a-Gal IgM antibodies within eight days of surgery (each group, n = 6). Kinetics of host inflammatory response on surgically explanted ATE xenografts was also studied. Immunostaining for a-Gal and T-antigen detected the presence of them in the native tissue but they were absent in processed ATE xenografts from the same tissue. A significant increase in the concentration of anti-a-Gal IgM antibodies was observed in the serum of bioprosthetic valve recipients as compared to ATE xenograft recipients (P<0.05). Organised collagen, and decreased inflammatory response with increase in endothelisation and vascularisation was evident beyond one year of surgery as compared to early periods in ATE xenografts. This study demonstrates that decellularisation of xenografts and further processing of these tissues enabled reduction of inflammatory stimulus with autologous recellularisation with no calcification. © 2011 Published by European Association for Cardio-Thoracic Surgery.

Mathapati S.,Indian Institute of Technology Madras | Mathapati S.,Frontier Lifeline Pvt. Ltd. | Mathapati S.,National University of Singapore | Bishi D.K.,Indian Institute of Technology Madras | And 7 more authors.
Materials Science and Engineering C | Year: 2013

Glutaraldehyde (GLUT) processing, cellular antigens, calcium ions in circulation, and phospholipids present in the native tissue are predominantly responsible for calcification, degeneration, and lack of natural microenvironment for host progenitor cell migration in tissue implants. The study presents an improved methodology for adhesion and proliferation of endothelial progenitor cells (EPCs) without significant changes in biomechanical and biodegradation properties of the processed acellular bovine pericardium. The anti-calcification potential of the processed tissue was enhanced by detoxification of GLUT-cross-linked bovine pericardium by decellularization, pretreating it with ethanol or removing the free aldehydes by citric acid treatment and lyophilization. The treated tissues were assessed for biomechanical properties, GLUT ligand quantification, adhesion, proliferation of EPCs, and biodegradability. The results indicate that there was no significant change in biomechanical properties and biodegradability when enzymatic hydrolysis (p > 0.05) is employed in detoxified acellular GLUT cross-linked tissue (DBP-G-CA-ET), compared with the native detoxified GLUT cross-linked bovine pericardium (NBP-G-CA-ET). DBP-G-CA-ET exhibited a significant (p > 0.05) increase in the viability of EPCs and cell adhesion as compared to acellular GLUT cross-linked bovine pericardium (p < 0.05). Lyophilized acellular detoxified GLUT cross-linked bovine pericardium, employed in our study as an alternative to conventional GLUT cross-linked bovine pericardium, might provide longer durability and better biocompatibility, and reduce calcification. The developed bovine pericardium patches could be used in cardiac reconstruction and repair, arteriotomy, soft tissue repair, and general surgical procedures with tissue regeneration dimensions. © 2012 Elsevier B.V. All Rights Reserved.

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