Vandenburgh H.,The Miriam Hospital |
Vandenburgh H.,Myomics Inc.
Tissue Engineering - Part B: Reviews
Tissue engineering for in vitro drug-screening applications based on tissue function is an active area of translational research. Compared to targeted high-throughput drug-screening methods that rapidly analyze hundreds of thousands of compounds affecting a single biochemical reaction or gene expression, high-content screening (HCS) with engineered tissues is more complex and based on the cumulative positive and negative effects of a compound on the multiple pathways altering tissue function. It may therefore serve as better predictor of in vivo activity and serve as a bridge between high-throughput drug screening and in vivo animal studies. In the case of the musculoskeletal system, tissue function includes determining improvements in the mechanical properties of bone, tendon, cartilage, and, for skeletal muscle, contractile properties such as rate of contraction/relaxation, force generation, fatigability, and recovery from fatigue. HCS of compound banks with engineered tissues requires miniature musculoskeletal organs as well as automated functional testing. The resulting technologies should be rapid, cost effective, and reduce the number of small animals required for follow-on in vivo studies. Identification of compounds that improve the repair/regeneration of damaged tissues in vivo would have extensive clinical applications for treating musculoskeletal disorders. © Copyright 2010, Mary Ann Liebert, Inc. Source
Borselli C.,Harvard University |
Borselli C.,University of Naples Federico II |
Cezar C.A.,Harvard University |
Shvartsman D.,Harvard University |
And 2 more authors.
Many cell types of therapeutic interest, including myoblasts, exhibit reduced engraftment if cultured prior to transplantation. This study investigated whether polymeric scaffolds that direct cultured myoblasts to migrate outwards and repopulate the host damaged tissue, in concert with release of angiogenic factors designed to enhance revascularizaton of the regenerating tissue, would enhance the efficacy of this cell therapy and lead to functional muscle regeneration. This was investigated in the context of a severe injury to skeletal muscle tissue involving both myotoxin-mediated direct damage and induction of regional ischemia. Local and sustained release of VEGF and IGF-1 from macroporous scaffolds used to transplant and disperse cultured myogenic cells significantly enhanced their engraftment, limited fibrosis, and accelerated the regenerative process. This resulted in increased muscle mass and, improved contractile function. These results demonstrate the importance of finely controlling the microenvironment of transplanted cells in the treatment of severe muscle damage. © 2011 Elsevier Ltd. Source
Lee P.H.U.,The Miriam Hospital |
Lee P.H.U.,Stanford University |
Vandenburgh H.H.,The Miriam Hospital |
Vandenburgh H.H.,Myomics Inc.
Tissue Engineering - Part A
Skeletal muscle atrophy has been well characterized in various animal models, and while certain pathways that lead to disuse atrophy and its associated functional deficits have been well studied, available drugs to counteract these deficiencies are limited. An ex vivo tissue-engineered skeletal muscle offers a unique opportunity to study skeletal muscle physiology in a controlled in vitro setting. Primary mouse myoblasts isolated from adult muscle were tissue engineered into bioartificial muscles (BAMs) containing hundreds of aligned postmitotic muscle fibers expressing sarcomeric proteins. When electrically stimulated, BAMs generated measureable active forces within 2-3 days of formation. The maximum isometric tetanic force (Po) increased for ∼3 weeks to 2587±502 μN/BAM and was maintained at this level for greater than 80 days. When BAMs were reduced in length by 25% to 50%, muscle atrophy occurred in as little as 6 days. Length reduction resulted in significant decreases in Po (50.4%), mean myofiber cross-sectional area (21.7%), total protein synthesis rate (22.0%), and noncollagenous protein content (6.9%). No significant changes occurred in either the total metabolic activity or protein degradation rates. This study is the first in vitro demonstration that length reduction alone can induce skeletal muscle atrophy, and establishes a novel in vitro model for the study of skeletal muscle atrophy. © Copyright 2013, Mary Ann Liebert, Inc. Source
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 98.14K | Year: 2008
DESCRIPTION (provided by applicant): Myomics, Inc. has developed High Content Drug Screening (HCS) technology for in vitro testing of compounds which alter contractile forces generated by miniaturized tissue engineered organs (Myo-Force Assay SystemTM, MFA STM). Myomics' 3-D tissue/force sensor composite is capable of long term studies (1-4 weeks) and provides force as well as electrophysiological activity data in response to a drug or multiple drugs in a nondestructive, repetitive fashion. Such long term st udies can determine effects of drugs on tissues which may not be apparent in shorter term single biochemical High Throughput Screening (HTS) assays. Unlike cell-based HCS assays, MFASTM retains properties of the original contractile tissue, allowing for fo llow-up histological and biochemical correlation to tissue contractile force. Since the physiological measurement of force is assayed, the effects of drugs on contractile properties are the sum result on multiple second messenger pathways (both positive an d negative effects). The technology may thus be a better predictor of subsequent in vivo activities. In addition, since the screening method does not target any particular known second messenger pathway as in most HTS and HCS assays, new pathway targets ma y be identified. Myomics has successfully tissue engineered skeletal muscle myoblasts into miniaturized bioartificial muscles (mBAMs) in a prototype 96 well format, reproducibly measured both isotonic (resting) and active (electrically- induced) contractil e forces, and validated the assay with known anabolic and catabolic factors. This Phase 1 SBIR project will extend the MFASTM technology to neonatal rat cardiomyocyte mBAMs (cBAMs) for potential use in screening for compounds to treat heart diseases affect ing heart force contraction or electrophysiological activity. Methods will be developed for the reproducible tissue engineering of cBAMS in a 96 well format and measurement of force generation with the MFASTM. Follow-up electrophysiological, biochemical, a nd histological assays will be performed to determine the differentiation state of the tissue by measuring electrical coupling, contractile protein isoform content, cellular organization, cell number and size. Successful completion of this project will all ow Myomics to utilize an automated 96 well plate MFASTM in a SBIR Phase II project to screen chemical compounds bank for potential treatment of heart disorders such as pathological cardiac hypertrophy or cardiac arrhythmias. Heart failure is a major public health problem and number one cause of death in industrialized nations. About 550,000 new cases occur in each year in the United States, and heart failure is the underlying or contributing cause of ~285,000 deaths per year and the estimated direct and ind irect costs (i.e., health care expenditures and loss of productivity, respectively) of heart failure in 2006 are estimated to be more than 25 billion. Few drugs are currently available to treat these disorders and Myomics' high throughput drug screening te chnology will enable the identification of new drugs candidates to attenuate cardiac disorders.
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 991.99K | Year: 2009
DESCRIPTION (provided by applicant): Duchenne Muscular Dystrophic (DMD) is a fatal genetic disease affecting tens of thousands of boys in the U.S. There is currently no cure for the disease and few drugs are available to slow the progressive loss in skeletal muscle strength. Glucocorticoids such as prednisone are one of the few classes of drugs in clinical use in DMD to slow the loss of muscle function, but have serious adverse side effects when used chronically. There is thus a great need to identify new compounds that can improve the longevity and quality of life of the boys with this devastating disease. Myomics has developed a phenotypic high content drug screening technology termed MyoForce Analysis System (MFASTM). It is comprised of tissue engineered skeletal muscle (Miniature BioArtificial Muscles or mBAMs) attached to micro-mechanical sensors in ninety-six microwell plates to quantitatively measure muscle contractile forces. These three-dimensional contractile tissues are composed of organized striated skeletal muscle fibers that generate directed force when electrically stimulated. Myomics' mBAM tissue/sensor composite is capable of repetitive nondestructive force measurements over days to weeks. Such long-term studies can determine cumulative effects of drugs on tissues and provides physiological data regarding tissue function. The physiological measurement of force generation by mBAMs is not limited to any particular known biochemical pathway, but rather the measurement of force is the result of both positive and negative drug effects. Thus, MFASTM will not only screen compounds for positive muscle strength effects through known as well as unknown pathways, but will more rapidly eliminate target compounds with potentially adverse side effects. In Myomics' Phase I SBIR project mBAMs were tissue engineered from conditionally immortalized myoblasts from the mdx mouse, the small animal model of DMD. These dystrophin negative mBAMs generated measureable tetanic forces that increased significantly when incubated with nine compounds that improve muscle strength in vivo. MFASTM was thus validated as a screen for new drugs to treat muscle weakness in DMD and will serve as an important bridge between target-based high throughput drug screening and follow-on in vivo animal studies; it provides a rapid and cost effective screen compared to in vivo testing. The purpose of this Phase II project is to (1) Screen commercially available banks of clinically tested small molecules (600-1200) for increased skeletal muscle strength; and (2) Determine whether compounds identified in (1) synergistically improve the benefits of glucocorticoid treatment. This SBIR Phase II project falls within several aspects of the NIH ROADMAP FOR MEDICAL RESEARCH including the use of innovative phenotypic drug screening instrumentation to better understand the metabolic components and networks within tissues, creating new models to help predict the body's response to disease treatment. PUBLIC HEALTH RELEVANCE: Duchene muscular dystrophy (DMD) is a genetically inherited fatal skeletal muscle disease with few treatments currently available for slowing the loss of muscle strength. Myomics' high content drug screening technology is aimed at identifying new drug candidates to attenuate skeletal muscle loss and thereby increase muscle strength. While not a cure for the disease, these new drug therapies are aimed at enhancing quality and longevity of life of the DMD patient.