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The host immune response to an implanted biomaterial, particularly the phenotype of infiltrating macrophages, is a key determinant of biocompatibility and downstream remodeling outcome. The present study used a subcutaneous rat model to compare the tissue response, including macrophage phenotype, remodeling potential, and calcification propensity of a biologic scaffold composed of glutaraldehyde-fixed bovine pericardium (GF-BP), the standard of care for heart valve replacement, with those of an electrospun polycarbonate-based supramolecular polymer scaffold (ePC-UPy), urinary bladder extracellular matrix (UBM-ECM), and a polypropylene mesh (PP). The ePC-UPy and UBM-ECM materials induced infiltration of mononuclear cells throughout the thickness of the scaffold within 2 days and neovascularization at 14 days. GF-BP and PP elicited a balance of pro-inflammatory (M1-like) and anti-inflammatory (M2-like) macrophages, while UBM-ECM and ePC-UPy supported a dominant M2-like macrophage phenotype at all timepoints. Relative to GF-BP, ePC-UPy was markedly less susceptible to calcification for the 180 day duration of the study. UBM-ECM induced an archetypical constructive remodeling response dominated by M2-like macrophages and the PP caused a typical foreign body reaction dominated by M1-like macrophages. The results of this study highlight the divergent macrophage and host remodeling response to biomaterials with distinct physical and chemical properties and suggest that the rat subcutaneous implantation model can be used to predict in vivo biocompatibility and regenerative potential for clinical application of cardiovascular biomaterials.

Suppressive effects of extracellular matrix (ECM) upon various cancers have been reported. Glioblastoma multiforme has poor prognosis and new therapies are desired. This work investigated the effects of a saline-soluble fraction of urinary bladder ECM (ECM-SF) upon glioma cells. Viability at 24 hours in 1, 5, or 10 mg/mL ECM-SF-spiked media was evaluated in primary glioma cells (0319, 1015, 1119), glioma cell lines (A172, T98G, U87MG, C6), and brain cell lines (HCN-2, HMC3). Viability universally decreased at 5 and 10 mg/mL with U87MG, HCN-2, and HCM3 being least sensitive. Apoptosis in 0319 and 1119 cells was confirmed via NucView 488. Bi-weekly intravenous injection of ECM-SF (120 mg/kg) for 10 weeks in Sprague-Dawley rats did not affect weight, temperature, complete blood count, or multi-organ histology (

Tissue engineering materials play a key role in how closely the complex architectural and functional characteristics of native healthy tissue can be replicated. Traditional natural and synthetic materials are superseded by bespoke materials that cross the boundary between these two categories. Here we present hydrogels that are derived from decellularised extracellular matrix and those that are synthesised from de novo α-helical peptides. We assess in vitro activation of murine macrophages to our hydrogels and whether these gels induce an M1-like or M2-like phenotype. This was followed by the in vivo immune macrophage response to hydrogels injected into rat partial-thickness abdominal wall defects. Over 28 days we observe an increase in mononuclear cell infiltration at the hydrogel-tissue interface without promoting a foreign body reaction and see no evidence of hydrogel encapsulation or formation of multinucleate giant cells. We also note an upregulation of myogenic differentiation markers and the expression of anti-inflammatory markers Arginase1, IL-10, and CD206, indicating pro-remodelling for all injected hydrogels. Furthermore, all hydrogels promote an anti-inflammatory environment after an initial spike in the pro-inflammatory phenotype. No difference between the injected site and the healthy tissue is observed after 28 days, indicating full integration. These materials offer great potential for future applications in regenerative medicine and towards unmet clinical needs. STATEMENT OF SIGNIFICANCE: Materials play a key role in how closely the complex architectural and functional characteristics of native healthy tissue can be replicated in tissue engineering. Here we present injectable hydrogels derived from decellularised extracellular matrix and de novo designed α-helical peptides. Over 28 days in the rat abdominal wall we observe an increase in mononuclear cell infiltration at the hydrogel-tissue interface with no foreign body reaction, no evidence of hydrogel encapsulation and no multinucleate giant cells. Our data indicate pro-remodelling and the promotion of an anti-inflammatory environment for all injected hydrogels with evidence of full integration with healthy tissue after 28 days. These unique materials offer great potential for future applications in regenerative medicine and towards designing materials for unmet clinical needs.

Objectives The present study compared physical, mechanical, and biologic characteristics of 4 clinically available surgical sealants for cardiovascular repair. Methods BioGlue (Cryolife Inc, Kennesaw, Ga), PreveLeak (Mallinckrodt Pharmaceuticals, St Louis, Mo), Tridyne VS (BD, Franklin Lakes, NJ), and Coseal (Baxter Healthcare Corporation, Westlake Village, Calif) were compared for the following properties: hydrated swelling, cytocompatibility, burst strength, biaxial stretching (elasticity), and in vitro degradation. Results Sealants showed a wide range of swelling upon hydration. By gravimetric and volumetric measurement, swelling was greatest for Coseal followed by Tridyne VS, BioGlue, and PreveLeak. Tridyne VS was the most cytocompatible based on Alamar Blue assay results, supporting 85% cell survival compared with 36% to 39% survival with the other sealants. All sealants withstood pressure above mean arterial pressure (70-110 mm Hg) and physiologic systolic blood pressure (90-140 mm Hg) in an ex vivo arterial flow burst model; lowest peak pressure at failure was PreveLeak at 235 ± 48 mm Hg, and highest peak pressure at failure was BioGlue at 596 ± 72 mm Hg. Biaxial tensile testing showed no differences in elasticity between ex vivo porcine aorta and carotid arteries and Tridyne VS or Coseal, and BioGlue and PreveLeak were significantly stiffer. In vitro degradation time for Coseal was 6 days and 21 days for Tridyne VS. No degradation was observed in BioGlue or PreveLeak for 30 days. Conclusions Although all sealants withstood supraphysiologic arterial pressure, there were differences in characteristics that may be important in clinical outcome. Coseal degradation time was short compared with other sealants, whereas BioGlue and PreveLeak showed a significant compliance mismatch with native porcine carotid artery. Tridyne VS was significantly more cytocompatible than the other 3 sealants.

OBJECTIVES/SPECIFIC AIMS: Gliomas are the most lethal and common primary tumor type in the central nervous system across all age groups; affected adults have a life expectancy of just 14 months. As glioma cells invade the surrounding normal parenchyma they remodel the composition and ultrastructure of the surrounding extracellular matrix (ECM), suggesting that the native (i.e., “normal”) microenvironment is not ideal for their survival and proliferation. Recent reports describe suppressive and/or lethal effects of mammalian ECM hydrogels derived from normal (nonneoplastic) sources upon various cancer types. ECM-based bioscaffolds placed at sites of neoplastic tissue resection in humans have never been reported to facilitate cancer recurrence. The objective of the present research is to evaluate mammalian ECM as a novel approach to glioma therapy. METHODS/STUDY POPULATION: ECM hydrogels from porcine dermis, small intestine, and urinary bladder were produced as described previously. Primary glioma cells were graciously supplied by Drs. Nduka Amankulor and Johnathan Engh, and U-87 MG were ordered through ATCC. Cells were plated onto tissue culture plastic at ~60% confluence and allowed to attach for 24 hours before treatment. The saline-soluble fraction (SSF) of ECM was obtained by mixing lyophilized, comminuted ECM with 0.9% saline for 24 hours then filtering the resulting mixture through a 10 kDa molecular weight cutoff column. All assays and kits were followed according to the manufacturer’s instructions. Cell viability was measured via MTT assay (Vybrant® MTT Cell Proliferation Assay, Invitrogen) and by live/dead staining (LIVE/DEAD® Cell Imaging Kit, Invitrogen). Time lapse videos were created by taking images every 20 minutes for 18 hours (phase-contrast) or every 10 minutes for 12 hours (darkfield). NucView reagent was ordered from Biotium. Temozolomide was ordered through Abmole. All in vivo work was conducted according to protocols approved by the University of Pittsburgh’s IACUC office. RESULTS/ANTICIPATED RESULTS: ECM hydrogels derived from porcine dermis, small intestine, or urinary bladder all decreased the viability of primary glioma cells in vitro, with urinary bladder extracellular matrix (UBM) having the most dramatic effects. The SSF of UBM (UBM-SSF), devoid of the fibrillar, macromolecular components of ECM, was sufficient to recapitulate this detrimental effect upon neoplastic cells in vitro and was used for the remainder of the experiments described herein. In a cell viability assay normalized to the media treatment, non-neoplastic CHME5 and N1E-115 cells scored 103% and 114% after 48 hours when treated with UBM-SSF and 2 primary high-grade glioma cell types scored 17% and 30.5% with UBM-SSF (n=2). Phase-contrast time-lapse video showed CHME5 and HFF thriving in the presence of UBM-SSF for 18 hours while most primary glioma cells shriveled and died within this time. Darkfield time-lapse video of wells containing Nucview dye, fluorescent upon cleavage by active caspase-3, confirmed that within 12 hours most primary glioma cells underwent apoptosis while CHME5 and HFF did not. In culture with primary astrocytes, high grade primary glioma cells, and U-87 MG glioma cells for 24 hours, UBM-SSF was found to significantly increase the population of primary astrocytes compared with media (ppp