Full Text Journal Articles by
Author Andrew J Putnam


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Injectable pre-cultured tissue modules catalyze the formation of extensive functional microvasculature in vivo.

Nicole E Friend, Ana Y Rioja, Yen P Kong, Jeffrey A Beamish, Xiaowei Hong, Julia C Habif, Jonathan R Bezenah, Cheri X Deng, Jan P Stegemann, Andrew J Putnam,

Revascularization of ischemic tissues is a major barrier to restoring tissue function in many pathologies. Delivery of pro-angiogenic factors has shown some benefit, but it is difficult to recapitulate the complex set of factors required to form stable vasculature. Cell-based therapies and pre-vascularized tissues have shown promise, but the former ... Read more >>

Sci Rep (Scientific reports)
[2020, 10(1):15562]

Cited: 0 times

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Spatiotemporal control of micromechanics and microstructure in acoustically-responsive scaffolds using acoustic droplet vaporization.

Mitra Aliabouzar, Christopher D Davidson, William Y Wang, Oliver D Kripfgans, Renny T Franceschi, Andrew J Putnam, J Brian Fowlkes, Brendon M Baker, Mario L Fabiilli,

Acoustically-responsive scaffolds (ARSs), which are composite fibrin hydrogels, have been used to deliver regenerative molecules. ARSs respond to ultrasound in an on-demand, spatiotemporally-controlled manner via a mechanism termed acoustic droplet vaporization (ADV). Here, we study the ADV-induced, time-dependent micromechanical and microstructural changes to the fibrin matrix in ARSs using confocal ... Read more >>

Soft Matter (Soft matter)
[2020, 16(28):6501-6513]

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Spatially-directed cell migration in acoustically-responsive scaffolds through the controlled delivery of basic fibroblast growth factor.

Xiaofang Lu, Hai Jin, Carole Quesada, Easton C Farrell, Leidan Huang, Mitra Aliabouzar, Oliver D Kripfgans, J Brian Fowlkes, Renny T Franceschi, Andrew J Putnam, Mario L Fabiilli,

Hydrogels are commonly used in regenerative medicine for the delivery of growth factors (GFs). The spatial and temporal presentations of GFs are critical for directing regenerative processes, yet conventional hydrogels do not enable such control. We have developed a composite hydrogel, termed an acoustically-responsive scaffold (ARS), where release of a ... Read more >>

Acta Biomater (Acta biomaterialia)
[2020, 113:217-227]

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Prevalence of mitral annular disjunction in patients with mitral valve prolapse and severe regurgitation.

Andrew J Putnam, Kalie Kebed, Victor Mor-Avi, Nina Rashedi, Deyu Sun, Brooke Patel, Husam Balkhy, Roberto M Lang, Amit R Patel,

Mitral annular disjunction (MAD) is routinely diagnosed by cardiac imaging, mostly by echocardiography, and shown to be a risk factor for ventricular arrhythmias. While MAD is associated with mitral valve (MV) prolapse (MVP), it is unknown which patients with MAD are at higher risk and which additional imaging features may ... Read more >>

Int J Cardiovasc Imaging (The international journal of cardiovascular imaging)
[2020, 36(7):1363-1370]

Cited: 0 times

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Viscoelastic characterization of diabetic and non-diabetic human adipose tissue.

Benjamin A Juliar, Clarissa Strieder-Barboza, Monita Karmakar, Carmen G Flesher, Nicki A Baker, Oliver A Varban, Carey N Lumeng, Andrew J Putnam, Robert W O'Rourke,

BACKGROUND:Obesity-induced chronic inflammation and fibrosis in adipose tissue contributes to the progression of type 2 diabetes mellitus (DM). While fibrosis is known to induce mechanical stiffening of numerous tissue types, it is unknown whether DM is associated with alterations in adipose tissue mechanical properties. OBJECTIVE:The purpose of this study was ... Read more >>

Biorheology (Biorheology)
[2020, 57(1):15-26]

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Cell-mediated matrix stiffening accompanies capillary morphogenesis in ultra-soft amorphous hydrogels.

Benjamin A Juliar, Jeffrey A Beamish, Megan E Busch, David S Cleveland, Likitha Nimmagadda, Andrew J Putnam,

There is a critical need for biomaterials that support robust neovascularization for a wide-range of clinical applications. Here we report how cells alter tissue-level mechanical properties during capillary morphogenesis using a model of endothelial-stromal cell co-culture within poly(ethylene glycol) (PEG) based hydrogels. After a week of culture, we observed substantial ... Read more >>

Biomaterials (Biomaterials)
[2020, 230:119634]

Cited: 0 times

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Deciphering the relative roles of matrix metalloproteinase- and plasmin-mediated matrix degradation during capillary morphogenesis using engineered hydrogels.

Jeffrey A Beamish, Benjamin A Juliar, David S Cleveland, Megan E Busch, Likitha Nimmagadda, Andrew J Putnam,

Extracellular matrix (ECM) remodeling is essential for the process of capillary morphogenesis. Here we employed synthetic poly(ethylene glycol) (PEG) hydrogels engineered with proteolytic specificity to either matrix metalloproteinases (MMPs), plasmin, or both to investigate the relative contributions of MMP- and plasmin-mediated ECM remodeling to vessel formation in a 3D-model of ... Read more >>

J. Biomed. Mater. Res. Part B Appl. Biomater. (Journal of biomedical materials research. Part B, Applied biomaterials)
[2019, 107(8):2507-2516]

Cited: 1 time

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Nonadhesive Alginate Hydrogels Support Growth of Pluripotent Stem Cell-Derived Intestinal Organoids.

Meghan M Capeling, Michael Czerwinski, Sha Huang, Yu-Hwai Tsai, Angeline Wu, Melinda S Nagy, Benjamin Juliar, Nambirajan Sundaram, Yang Song, Woojin M Han, Shuichi Takayama, Eben Alsberg, Andres J Garcia, Michael Helmrath, Andrew J Putnam, Jason R Spence,

Human intestinal organoids (HIOs) represent a powerful system to study human development and are promising candidates for clinical translation as drug-screening tools or engineered tissue. Experimental control and clinical use of HIOs is limited by growth in expensive and poorly defined tumor-cell-derived extracellular matrices, prompting investigation of synthetic ECM-mimetics for ... Read more >>

Stem Cell Reports (Stem cell reports)
[2019, 12(2):381-394]

Cited: 6 times

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Assessing the ability of human endothelial cells derived from induced-pluripotent stem cells to form functional microvasculature in vivo.

Jonathan R Bezenah, Ana Y Rioja, Benjamin Juliar, Nicole Friend, Andrew J Putnam,

Forming functional blood vessel networks is a major clinical challenge in the fields of tissue engineering and therapeutic angiogenesis. Cell-based strategies to promote neovascularization have been widely explored, but cell sourcing remains a significant limitation. Induced-pluripotent stem cell-derived endothelial cells (iPSC-ECs) are a promising, potentially autologous, alternative cell source. However, ... Read more >>

Biotechnol. Bioeng. (Biotechnology and bioengineering)
[2019, 116(2):415-426]

Cited: 2 times

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A systems mechanobiology model to predict cardiac reprogramming outcomes on different biomaterials.

Yen P Kong, Ana Y Rioja, Xufeng Xue, Yubing Sun, Jianping Fu, Andrew J Putnam,

During normal development, the extracellular matrix (ECM) regulates cell fate mechanically and biochemically. However, the ECM's influence on lineage reprogramming, a process by which a cell's developmental cycle is reversed to attain a progenitor-like cell state followed by subsequent differentiation into a desired cell phenotype, is unknown. Using a material ... Read more >>

Biomaterials (Biomaterials)
[2018, 181:280-292]

Cited: 0 times

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Biofabrication of injectable fibrin microtissues for minimally-invasive therapies: application of surfactants.

Ramkumar T Annamalai, Tapan Naik, Haley Prout, Andrew J Putnam, Jan P Stegemann,

Microtissues created from the protein fibrin and containing embedded cells can be used in modular tissue engineering approaches to create larger, hierarchical and complex tissue structures. In this paper we demonstrate an emulsification-based method for the production of such fibrin microtissues containing fibroblasts (FB) and endothelial cells (EC) and designed ... Read more >>

Biomed Mater (Biomedical materials (Bristol, England))
[2018, 13(4):045005]

Cited: 1 time

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Evaluating the potential of endothelial cells derived from human induced pluripotent stem cells to form microvascular networks in 3D cultures.

Jonathan R Bezenah, Yen P Kong, Andrew J Putnam,

A major translational challenge in the fields of therapeutic angiogenesis and regenerative medicine is the need to create functional microvasculature. The purpose of this study was to assess whether a potentially autologous endothelial cell (EC) source derived from human induced pluripotent stem cells (iPSC-ECs) can form the same robust, stable ... Read more >>

Sci Rep (Scientific reports)
[2018, 8(1):2671]

Cited: 8 times

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Characterization of the crosslinking kinetics of multi-arm poly(ethylene glycol) hydrogels formed via Michael-type addition.

Jiwon Kim, Yen P Kong, Steven M Niedzielski, Rahul K Singh, Andrew J Putnam, Ariella Shikanov,

Tunable properties of multi-arm poly(ethylene glycol) (PEG) hydrogel, crosslinked by Michael-type addition, support diverse applications in tissue engineering. Bioactive modification of PEG is achieved by incorporating integrin binding sequences, like RGD, and crosslinking with tri-functional protease sensitive crosslinking peptide (GCYKNRGCYKNRCG), which compete for the same reactive groups in PEG. This ... Read more >>

Soft Matter (Soft matter)
[2016, 12(7):2076-2085]

Cited: 11 times

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The Synergistic Effects of Matrix Stiffness and Composition on the Response of Chondroprogenitor Cells in a 3D Precondensation Microenvironment.

Bita Carrion, Mohammad F Souzanchi, Victor T Wang, Gopinath Tiruchinapally, Ariella Shikanov, Andrew J Putnam, Rhima M Coleman,

Improve functional quality of cartilage tissue engineered from stem cells requires a better understanding of the functional evolution of native cartilage tissue. Therefore, a biosynthetic hydrogel was developed containing RGD, hyaluronic acid and/or type-I collagen conjugated to poly(ethylene glycol) acrylate to recapitulate the precondensation microenvironment of the developing limb. Conjugation ... Read more >>

Adv Healthc Mater (Advanced healthcare materials)
[2016, 5(10):1192-1202]

Cited: 8 times

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Effects of tissue stiffness, ultrasound frequency, and pressure on histotripsy-induced cavitation bubble behavior.

Eli Vlaisavljevich, Kuang-Wei Lin, Matthew T Warnez, Rahul Singh, Lauren Mancia, Andrew J Putnam, Eric Johnsen, Charles Cain, Zhen Xu,

Histotripsy is an ultrasound ablation method that controls cavitation to fractionate soft tissue. In order to effectively fractionate tissue, histotripsy requires cavitation bubbles to rapidly expand from nanometer-sized initial nuclei into bubbles often larger than 50 µm. Using a negative pressure high enough to initiate a bubble cloud and expand bubbles ... Read more >>

Phys Med Biol (Physics in medicine and biology)
[2015, 60(6):2271-2292]

Cited: 20 times

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Effects of ultrasound frequency and tissue stiffness on the histotripsy intrinsic threshold for cavitation.

Eli Vlaisavljevich, Kuang-Wei Lin, Adam Maxwell, Matthew T Warnez, Lauren Mancia, Rahul Singh, Andrew J Putnam, Brian Fowlkes, Eric Johnsen, Charles Cain, Zhen Xu,

Histotripsy is an ultrasound ablation method that depends on the initiation of a cavitation bubble cloud to fractionate soft tissue. Previous work has indicated that a cavitation cloud can be formed by a single pulse with one high-amplitude negative cycle, when the negative pressure amplitude directly exceeds a pressure threshold ... Read more >>

Ultrasound Med Biol (Ultrasound in Medicine & Biology)
[2015, 41(6):1651-1667]

Cited: 30 times

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The Instructive Role of the Vasculature in Stem Cell Niches.

Andrew J Putnam,

An important hallmark of many adult stem cell niches is their proximity to the vasculature in vivo, a feature common to neural stem cells (NSCs), mesenchymal stem cells (MSCs) from bone marrow, adipose, and other tissues, hematopoietic stem cells (HSCs), and many tumor stem cells. This review summarizes key studies ... Read more >>

Biomater Sci (Biomaterials science)
[2014, 2(11):1562-1573]

Cited: 8 times

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Increased thermal pain sensitivity in animals exposed to chronic high dose Vicodin but not pure hydrocodone.

Thomas F O'Connell, Patrick S Carpenter, Nadia Caballero, Andrew J Putnam, Joshua T Steere, Gregory J Matz, Eileen M Foecking,

Vicodin, the combination drug of acetaminophen and the opioid hydrocodone, is one of the most prescribed drugs on the market today. Opioids have demonstrated the ability to paradoxically cause increased pain sensitivity to users in a phenomena called opioid-induced hyperalgesia (OIH). While selected opioids have been shown to produce OIH ... Read more >>

Pain Physician (Pain physician)
[2014, 17(4):353-357]

Cited: 0 times

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Protease-sensitive PEG hydrogels regulate vascularization in vitro and in vivo.

Marina Vigen, Jacob Ceccarelli, Andrew J Putnam,

Forming functional blood vessel networks in engineered or ischemic tissues is a significant scientific and clinical hurdle. Poly(ethylene glycol) (PEG)-based hydrogels are adapted to investigate the role of mechanical properties and proteolytic susceptibility on vascularization. Four arm PEG vinyl sulfone is polymerized by Michael-type addition with cysteine groups on a ... Read more >>

Macromol Biosci (Macromolecular bioscience)
[2014, 14(10):1368-1379]

Cited: 13 times

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Extracellular matrix elasticity and topography: material-based cues that affect cell function via conserved mechanisms.

Isaac A Janson, Andrew J Putnam,

Chemical, mechanical, and topographic extracellular matrix (ECM) cues have been extensively studied for their influence on cell behavior. These ECM cues alter cell adhesion, cell shape, and cell migration and activate signal transduction pathways to influence gene expression, proliferation, and differentiation. ECM elasticity and topography, in particular, have emerged as ... Read more >>

J Biomed Mater Res A (Journal of biomedical materials research. Part A)
[2015, 103(3):1246-1258]

Cited: 32 times

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Nanotopographic substrates of poly (methyl methacrylate) do not strongly influence the osteogenic phenotype of mesenchymal stem cells in vitro.

Isaac A Janson, Yen P Kong, Andrew J Putnam,

The chemical, mechanical, and topographical features of the extracellular matrix (ECM) have all been documented to influence cell adhesion, gene expression, migration, proliferation, and differentiation. Topography plays a key role in the architecture and functionality of various tissues in vivo, thus raising the possibility that topographic cues can be instructive ... Read more >>

PLoS ONE (PloS one)
[2014, 9(3):e90719]

Cited: 8 times

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Matrix identity and tractional forces influence indirect cardiac reprogramming.

Yen P Kong, Bita Carrion, Rahul K Singh, Andrew J Putnam,

Heart regeneration through in vivo cardiac reprogramming has been demonstrated as a possible regenerative strategy. While it has been reported that cardiac reprogramming in vivo is more efficient than in vitro, the influence of the extracellular microenvironment on cardiac reprogramming remains incompletely understood. This understanding is necessary to improve the ... Read more >>

Sci Rep (Scientific reports)
[2013, 3:3474]

Cited: 14 times

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Stem cells derived from tooth periodontal ligament enhance functional angiogenesis by endothelial cells.

Shamima Yeasmin, Jacob Ceccarelli, Marina Vigen, Bita Carrion, Andrew J Putnam, Susan A Tarle, Darnell Kaigler,

In regenerative medicine approaches involving cell therapy, selection of the appropriate cell type is important in that the cells must directly (differentiation) or indirectly (trophic effects) participate in the regenerative response. Regardless of the mode of action of the cells, angiogenesis underlies the success of these approaches. Stem cells derived ... Read more >>

Tissue Eng Part A (Tissue engineering. Part A)
[2014, 20(7-8):1188-1196]

Cited: 10 times

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Capillary morphogenesis in PEG-collagen hydrogels.

Rahul K Singh, Dror Seliktar, Andrew J Putnam,

A wide variety of hydrogels have been explored as 3D culture platforms and for applications in tissue engineering. Hydrogels formed from natural extracellular matrix (ECM) proteins readily support the formation of vasculature in vitro, but only a handful of hydrogels composed of synthetic materials have shown anything comparable. This relative ... Read more >>

Biomaterials (Biomaterials)
[2013, 34(37):9331-9340]

Cited: 24 times

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Bone marrow-derived mesenchymal stem cells enhance angiogenesis via their α6β1 integrin receptor.

Bita Carrion, Yen P Kong, Darnell Kaigler, Andrew J Putnam,

Bone marrow-derived mesenchymal stem cells (BMSCs) facilitate the angiogenic response of endothelial cells (ECs) within three-dimensional (3D) matrices in vivo and in engineered tissues in vitro in part through paracrine mediators and by acting as stabilizing pericytes. However, the molecular interactions between BMSCs and nascent tubules during the process of ... Read more >>

Exp. Cell Res. (Experimental cell research)
[2013, 319(19):2964-2976]

Cited: 31 times

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