University–industry linkages and academic engagements: individual behaviours and firms’ barriers. Introduction to the special section

The article introduces the special section on “University–industry linkages and academic engagements: Individual behaviours and firms’ barriers”. We first revisit the latest developments of the literature and policy interest on university–industry research. We then build upon the extant literature and unpack the concept of academic engagement by further exploring the heterogeneity of UI linkages along a set of dimensions and actors involved. These are: (1) Incentives and behaviours of individual academic entrepreneurs; (2) Firms’ barriers to cooperation with public research institutions; (3) Individual behaviours, incentives and organizational bottlenecks in late developing countries. We summarize the individual contributions along these dimensions. There are overlooked individual characteristics that affect the degree of engagement of academics and scholars in cooperating with other organizations, of which gender and the non-academic background of individuals are most crucial. The notion of academic engagement should be enlarged to aspects that go beyond the commercialization or patenting of innovation, but embrace social and economic impact more at large. From the perspective of the firm, barriers to innovation might exert an effect on the likelihood to cooperate with universities and public research institutes, most especially to cope with lack of finance or access to frontier knowledge. We finally propose a research agenda that addresses the challenges ahead

Epicardial cells derived from human embryonic stem cells augment cardiomyocyte-driven heart regeneration.

The epicardium and its derivatives provide trophic and structural support for the developing and adult heart. Here we tested the ability of human embryonic stem cell (hESC)-derived epicardium to augment the structure and function of engineered heart tissue in vitro and to improve efficacy of hESC-cardiomyocyte grafts in infarcted athymic rat hearts. Epicardial cells markedly enhanced the contractility, myofibril structure and calcium handling of human engineered heart tissues, while reducing passive stiffness compared with mesenchymal stromal cells. Transplanted epicardial cells formed persistent fibroblast grafts in infarcted hearts. Cotransplantation of hESC-derived epicardial cells and cardiomyocytes doubled graft cardiomyocyte proliferation rates in vivo, resulting in 2.6-fold greater cardiac graft size and simultaneously augmenting graft and host vascularization. Notably, cotransplantation improved systolic function compared with hearts receiving either cardiomyocytes alone, epicardial cells alone or vehicle. The ability of epicardial cells to enhance cardiac graft size and function makes them a promising adjuvant therapeutic for cardiac repair.: This work was supported by the British Heart Foundation (BHF; Grants NH/11/1/28922, G1000847, FS/13/29/30024 and FS/18/46/33663), Oxford-Cambridge Centre for Regenerative Medicine (RM/13/3/30159), the UK Medical Research Council (MRC) and the Cambridge Hospitals National Institute for Health Research Biomedical Research Centre funding (SS), as well as National Institutes of Health Grants P01HL094374, P01GM081619, R01HL12836 and a grant from the Fondation Leducq Transatlantic Network of Excellence (CEM). J.B. was supported by a Cambridge National Institute for Health Research Biomedical Research Centre Cardiovascular Clinical Research Fellowship and subsequently, by a BHF Studentship (Grant FS/13/65/30441). DI received a University of Cambridge Commonwealth Scholarship. LG is supported by BHF Award RM/l3/3/30159 and LPO is funded by a Wellcome Trust Fellowship (203568/Z/16/Z). NF was supported by BHF grants RG/13/14/30314. NL was supported by the Biotechnology and Biological Sciences Research Council (Institute Strategic Programmes BBS/E/B/000C0419 and BBS/E/B/000C0434). SS and MB were supported by the British Heart Foundation Centre for Cardiovascular Research Excellence. Core support was provided by the Wellcome-MRC Cambridge Stem Cell Institute (203151/Z/16/Z), The authors thank Osiris for provision of the primary mesenchymal stem cells (59

Tissue Engineering Strategies to Improve Post-MI Engraftment of hESC-Derived Cardiomyocytes

Thesis (Ph.D.)--University of Washington, 2016-12Transplantation of stem cell-derived cardiomyocytes is a promising strategy for repairing damaged cardiac muscle following a myocardial infarction. Our group and others have demonstrated both long-term engraftment and increased cardiac function after implantation in preclinical models using rodents and large animals. Despite this progress, there are still significant limitations to address in order to facilitate successful clinical translation of this therapy. Firstly, multiple delivery methods have been used to transplant stem cell-derived cardiomyocytes (hESC-cardiomyocytes) in rodents, including injecting cell suspensions and implanting engineered tissues. However, the ability of human cardiomyocytes to electrically and mechanically integrate with rodent myocardium using these delivery methods is not well understood. Secondly, current transplantation methods only retain a small fraction of implanted cells, leading to small graft size and an excess of cells needed for transplant. Here, we first conducted a comparative study to assess the engraftment and electromechanical integration of hESC-cardiomyocytes in the infarcted rat myocardium. This research demonstrated for the first time that human cardiomyocytes electrically integrate with the rat myocardium and beat in synchrony to rates over 6 Hz. We demonstrated that intramyocardially delivered cells (injected as a cell suspension or as cardiac micro-tissues) were electrically coupled to the host tissue, compared to no observed coupling when delivered as epicardial patches. All implant methods resulted in human myocardial grafts, however there was no improvement in graft area using these scaffold-free tissue engineering approaches compared to cell suspensions. To address this limitation, we designed an approach to improve engraftment and limit the number of cells required for implantation by promoting cardiomyocyte proliferation after transplantation. We developed a collagen-based hydrogel with the immobilized Notch ligand Delta-1, which was used in vitro to promote Notch signaling and increase cardiomyocyte proliferation by over 2-fold in engineered cardiac tissues. The optimized Notch-signaling hydrogel was then translated in vivo and used as a delivery vehicle for hESC-cardiomyocytes in the infarcted rat myocardium. This resulted in a 3-fold increase in cardiomyocyte proliferation and a 3-fold increase in graft size compared to controls. Taken collectively, the research in this dissertation highlights the potential of tissue engineering strategies to improve implantation of stem cell-derived cardiomyocytes, by promoting electromechanical integration and cell proliferation in preclinical models of myocardial infarction

Enhanced Electrical Integration of Engineered Human Myocardium via Intramyocardial versus Epicardial Delivery in Infarcted Rat Hearts.

Cardiac tissue engineering is a promising approach to provide large-scale tissues for transplantation to regenerate the heart after ischemic injury, however, integration with the host myocardium will be required to achieve electromechanical benefits. To test the ability of engineered heart tissues to electrically integrate with the host, 10 million human embryonic stem cell (hESC)-derived cardiomyocytes were used to form either scaffold-free tissue patches implanted on the epicardium or micro-tissue particles (~1000 cells/particle) delivered by intramyocardial injection into the left ventricular wall of the ischemia/reperfusion injured athymic rat heart. Results were compared to intramyocardial injection of 10 million dispersed hESC-cardiomyocytes. Graft size was not significantly different between treatment groups and correlated inversely with infarct size. After implantation on the epicardial surface, hESC-cardiac tissue patches were electromechanically active, but they beat slowly and were not electrically coupled to the host at 4 weeks based on ex vivo fluorescent imaging of their graft-autonomous GCaMP3 calcium reporter. Histologically, scar tissue physically separated the patch graft and host myocardium. In contrast, following intramyocardial injection of micro-tissue particles and suspended cardiomyocytes, 100% of the grafts detected by fluorescent GCaMP3 imaging were electrically coupled to the host heart at spontaneous rate and could follow host pacing up to a maximum of 300-390 beats per minute (5-6.5 Hz). Gap junctions between intramyocardial graft and host tissue were identified histologically. The extensive coupling and rapid response rate of the human myocardial grafts after intramyocardial delivery suggest electrophysiological adaptation of hESC-derived cardiomyocytes to the rat heart's pacemaking activity. These data support the use of the rat model for studying electromechanical integration of human cardiomyocytes, and they identify lack of electrical integration as a challenge to overcome in tissue engineered patches

Excitation response of stimulated hESC-cardiomyocytes in 2D culture <i>in vitro</i>.

<p>Spontaneous contraction rate was higher at 2 weeks with pacing at 1 and 6 Hz (*P < 0.05). Similarly, excitation threshold (ET) was significantly lower after 2 weeks of 1 and 6 Hz electrical pacing compared to unstimulated control. However, maximum capture rate (MCR) was not different among groups at any time point and all significant differences are lost after 4 weeks in culture.</p

Cardiomyocyte engraftment in injured rat hearts at 4 weeks.

<p>(A) Human cardiac grafts are identified by immunohistochemistry for GFP (brown, DAB) that binds to the GCaMP3 protein for the cell, micro-tissue particle (MTP), and patch groups. Hematoxalyin nuclear counterstain (blue). (B) Infarct scar area quantified by picrosirius red-positive area shows no difference between groups, normalized to left ventricular (LV) area at 4 weeks. (C) Graft size measured by GFP-positive graft area is normalized to LV area and is equivalent between groups (n = 8/group). (D) GFP-positive graft size declines with larger scar size for the cell grafts identified by histological analysis using Pearson correlation analysis (see text), but is weak and not significant in the micro-tissue particle or patch groups. (E) Micro-tissue particles (GFP, green) engrafted in the infarct region and lateral border within the septum of a rat heart are shown at 4 weeks stained for GFP (green) with DAPI (blue) nuclear stain. Topically applied dye (yellow-orange) marks the location of where an intramyocardial graft was detected by <i>ex vivo</i> imaging (arrow head). (F) Analysis of graft distribution in the heart indicates that cells and micro-tissue particles engraft in the scar, border zone, and healthy myocardium with equal distribution, while patch implants are found on the epicardium.</p

Intramyocardial implants have connexin 43-positive junctions with host cardiomyocytes.

<p>Evidence of connexin 43-positive gap junction formation between host cardiomyocytes and hESC-cardiomyocyte grafts was found for cell grafts (A) and micro-tissue particle grafts (B). Boxed region in left column is shown at 4-fold magnification in the right column, highlighting the junctions between graft and host (white arrow heads). Patch implants showed connexin 43-positive regions within the patch (boxed region and right column) and no evidence of gap junction formation with the host, as hESC-cardiomyocytes were physically separated from the host myocardium by scar tissue (C). g, graft; s, scar, h, host. Scale bar = 50 μm.</p

Human grafts contain striated cardiomyocytes.

<p>Confocal fluorescent imaging of engrafted hESC-cardiomyocytes at 4 weeks indicate that all three engraftment methods produce grafts that have high cardiac purity, as indicated by a double-positive stain for α-actinin (red) and GFP (green) with nuclear DAPI (blue), in representative images of all grafts. All grafts demonstrate sarcomere striations at higher magnification (far right). Scar tissue appears as the dark band separating the patch graft and host myocardium (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131446#pone.0131446.g003" target="_blank">Fig 3</a> for picrosirius red labeled scar, black arrowhead) and this extends to the edges of the patch (outside the field of view; not shown). White arrowhead in patch image points to GFP⁺/α-actinin^- non-cardiac cells. g, graft; s, scar, h, host. Scale bar = 500 μm and 50 μm (far right column).</p