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Sharma A.K.,Childrens Memorial Hospital of Chicago | Sharma A.K.,Northwestern University
Regenerative Medicine | Year: 2011

Patients that are afflicted with dysfunctional urinary bladders due to developmental defect, trauma or malignant transformation have limited treatment options that would allow for complete recapitulation of the urinary bladder. Hence, novel tissue engineering techniques that are successful in regenerating functional urinary bladder tissue for replacement therapy would be invaluable. Current tissue engineering techniques are hampered by several problems including choice of appropriate cell type, inadequate development of new blood vessels to the regenerated tissue, tissue innervation and primitive bioscaffold design. This article describes the recent advances in stem cell biology and the material sciences to address these problems, and attempts to improve upon current tissue engineering techniques to make successful regeneration of urinary bladder tissue a reality. © 2011 Future Medicine Ltd. Source

Le B.,Northwestern University | Sharma V.,Northwestern University | Kim D.,Northwestern University | Dupree J.,Northwestern University | Maizels M.,Childrens Memorial Hospital of Chicago
Journal of Pediatric Urology | Year: 2013

Objectives: Primary care physicians are the routine providers of neonatal circumcision, yet urologists commonly manage the complications. We previously identified a need for improved formalized training in neonatal circumcisions among ob-gyn residents. Here we extend the needs assessment to urology residents. Methods: From Nov 2008 to Nov 2009, ob-gyn and urology residents at our institution were given an online survey to assess comfort, education, and proficiency in pre-operative evaluation and performance of circumcisions. Results: 26/35 (74%) ob-gyn and 12/17 (65%) urology residents responded to the survey. 62% of ob-gyn and 33% of urology residents intended to perform neonatal circumcisions in practice. Both groups described having little formal training in neonatal circumcision. Ob-gyn residents felt more comfortable than urology residents in performing neonatal circumcisions [mean 5.9 vs. 4.3, p = 0.001; 1 (very uncomfortable) - 7 (very comfortable)], though urology residents' comfort level increased with resident year. Ob-gyn residents felt less comfortable than urology residents (mean 3.9 vs. 5.1, p = 0.031) evaluating if a newborn penis may undergo circumcision safely. Urology residents performed better than ob-gyn residents at identifying contraindications to routine circumcision from 10 scenarios (mean 63% vs. 42% p < 0.001). Both felt that an online module was a good alternative to practical experience. Conclusions: At our institution, ob-gyn and urology residents have little formalized training in neonatal circumcision. While ob-gyn residents are comfortable performing circumcisions, they feel less comfortable evaluating the newborn penis and correctly managed fewer scenarios than did urology residents. This highlights the need for further curriculum development and formalized training. © 2012 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved. Source

Thaker H.,Childrens Memorial Hospital of Chicago | Sharma A.K.,Childrens Memorial Hospital of Chicago | Sharma A.K.,Northwestern University
Stem Cells International | Year: 2012

The need for a consistent therapeutic approach to tendon injury repair is long overdue. Patients with tendon microtears or full ruptures are eligible for a wide range of invasive and non invasive interventions, often subjectively decided by the physician. Surgery produces the best outcomes, and while studies have been conducted to optimize graft constructs and to track outcomes, the data from these studies have been inconclusive on the whole. What has been established is a clear understanding of healthy tendon architecture and the inherent process of healing. With this knowledge, tissue regeneration efforts have achieved immense progress in scaffold design, cell line selection, and, more recently, the appropriate use of cytokines and growth factors. This paper evaluates the plasticity of bone-marrow-derived stem cells and the elasticity of recently developed biomaterials towards tendon regeneration efforts. Mesenchymal stem cells (MSCs), hematopoietic progenitor cells, and poly(1,8-octanediol co-citrate) scaffolds (POC) are discussed in the context of established grafting strategies. With POC scaffolds to cradle the growth of MSCs and hematopoietic progenitor cells, developing a fibroelastic network guided by cytokines and growth factors may contribute towards consistent graft constructs, enhanced functionality, and better patient outcomes. © Copyright 2012 Hatim Thaker and Arun K. Sharma. Source

Sharma A.K.,Childrens Memorial Hospital of Chicago | Sharma A.K.,Northwestern University | Cheng E.Y.,Childrens Memorial Hospital of Chicago | Cheng E.Y.,Northwestern University
Pediatric Urinary Bladder Tissue Engineering | Year: 2012

Tissue engineering is a multi-disciplinary field that is continually evolving and functions through the amalgamation of principles and practices derived from materials science, clinical medicine and the basic biological sciences. The goals of tissue engineering based therapies are to reconstitute the anatomic milieu and physiological function of diseased or damaged tissue in order to improve the poorly functioning target organ. With the advent of new synthetic polymers and advancements in stem cell biology, the combinatorial and/or synergistic effects of these disciplines has greatly advanced tissue engineering as a whole, particularly in the field of bladder tissue engineering. This book focuses on the current state of bladder tissue engineering with a specific emphasis on the use of autologous and allogenic cell sources, as well as biologic and synthetic matrices that influence cell growth and differentiation that can be used for future bladder tissue engineering applications. © 2012 by Nova Science Publishers, Inc. Source

Sharma A.K.,Childrens Memorial Hospital of Chicago | Sharma A.K.,Northwestern University | Bury M.I.,Childrens Memorial Hospital of Chicago | Fuller N.J.,Childrens Memorial Hospital of Chicago | And 12 more authors.
Journal of Biomedical Materials Research - Part A | Year: 2012

The ultimate success of in vivo organ formation utilizing ex vivo expanded "starter" tissues relies heavily upon the level of vascularization provided by either endogenous or artificial induction of angiogenic or vasculogenic events. To facilitate proangiogenic outcomes and promote tissue growth, an elastomeric scaffold previously shown to be instrumental in the urinary bladder regenerative process was modified to release proangiogenic growth factors. Carboxylic acid groups on poly(1,8-octanediol-co-citrate) films (POCfs) were modified with heparan sulfate creating a heparan binding POCf (HBPOCf). Release of proangiogenic growth factors vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF2), and insulin-like growth factor 1 (IGF-1) from HBPOCfs demonstrated an approximate threefold increase over controls during a 30-day time course in vitro. Atomic force microscopy demonstrated significant topological differences between films. Subcutaneous implantation of POCf alone, HBPOCf, POCf-VEGF, and HBPOCf-VEGF within the dorsa of nude rats yielded increased vascular growth in HBPOCf-VEGF constructs. Vessel quantification studies revealed that POCfs alone contained 41.1 ± 4.1 vessels/mm 2, while HBPOCf, POCf-VEGF, and HBPOCF-VEGF contained 41.7 ± 2.6, 76.3 ± 9.4, and 167.72 ± 15.3 vessels/mm 2, respectively. Presence of increased vessel growth was demonstrated by CD31 and vWF immunostaining in HBPOCf-VEGF implanted areas. Data demonstrate that elastomeric POCfs can be chemically modified and possess the ability to promote angiogenesis in vivo. Copyright © 2011 Wiley Periodicals, Inc. Source

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