title: The tissue response to photopolymerized PEG-p(HPMAm-lactate)-based hydrogels.
abstract: Hydrogels are three-dimensional networks of crosslinked hydrophilic polymers widely used for protein delivery and tissue engineering. To be eligible for in vivo applications, the hydrogels should not evoke an adverse tissue response. In this study the angiogenic and inflammatory responses in vivo after implantation of photopolymerized thermosensitive poly(hydroxypropyl methacrylamide lactate)-poly(ethyl copolymer hydrogels are investigated. Hydrogels consisting of polymers with different crosslink densities were subcutaneously implanted in Balb/c mice and histological evaluation of the tissue response was performed. The implants showed an acute and localized inflammatory reaction upon implantation, mainly characterized by a strong infiltration of granulocytes. The acute inflammatory reaction was followed by a milder chronic inflammation which was characterized by infiltration of macrophages and persistent but decreasing levels of granulocytes. The number of macrophages and blood vessels was associated with the biodegradation and resorption of the biomaterial and increased in time as the degradation of the materials progressed. The observed degradation rates in vivo correlated well with previously observed in vitro degradation rates, which suggests that hydrolysis is the main mechanism governing the degradation.
authors: Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, P.O. Box 80082, 3508 TB Utrecht, The Netherlands.
authors: Roberta
authors: R
authors: Censi
authors: Sander
authors: S
authors: van Putten
authors: Tina
authors: T
authors: Vermonden
authors: Piera
authors: P
authors: di Martino
authors: Cornelus F
authors: CF
authors: van Nostrum
authors: Martin C
authors: MC
authors: Harmsen
authors: Ruud A
authors: RA
authors: Bank
authors: Wim E
authors: WE
authors: Hennink
mesh_terms: D000178:Acrylamides / Q000009:adverse effects* / Q000276:immunology / Q000378:metabolism; D000818:Animals; D001672:Biocompatible Materials / Q000009:adverse effects* / Q000378:metabolism; D006098:Granulocytes / Q000166:cytology; D020100:Hydrogels / Q000009:adverse effects* / Q000378:metabolism; D007150:Immunohistochemistry; D007249:Inflammation / Q000139:chemically induced; D007773:Lactates / Q000009:adverse effects* / Q000276:immunology / Q000378:metabolism; D008264:Macrophages / Q000166:cytology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018919:Neovascularization, Physiologic; D011092:Polyethylene Glycols / Q000009:adverse effects* / Q000378:metabolism; D058105:Polymerization
chemical_list: D000178:Acrylamides; D001672:Biocompatible Materials; D020100:Hydrogels; D007773:Lactates; C509680:poly(N-(2-hydroxypropyl) methacrylamide lactate); D011092:Polyethylene Glycols