Despite great progress in engineering functional tissues for organ repair, including the heart, an invasive surgical approach is still required for their implantation. Here, we designed an elastic ...and microfabricated scaffold using a biodegradable polymer (poly(octamethylene maleate (anhydride) citrate)) for functional tissue delivery via injection. The scaffold's shape memory was due to the microfabricated lattice design. Scaffolds and cardiac patches (1 cm × 1 cm) were delivered through an orifice as small as 1 mm, recovering their initial shape following injection without affecting cardiomyocyte viability and function. In a subcutaneous syngeneic rat model, injection of cardiac patches was equivalent to open surgery when comparing vascularization, macrophage recruitment and cell survival. The patches significantly improved cardiac function following myocardial infarction in a rat, compared with the untreated controls. Successful minimally invasive delivery of human cell-derived patches to the epicardium, aorta and liver in a large-animal (porcine) model was achieved.
Biomaterials in myocardial tissue engineering Reis, Lewis A.; Chiu, Loraine L. Y.; Feric, Nicole ...
Journal of tissue engineering and regenerative medicine,
January 2016, Letnik:
10, Številka:
1
Journal Article
There is a clinical need for new, more effective treatments for chronic wounds in diabetic patients. Lack of epithelial cell migration is a hallmark of nonhealing wounds, and diabetes often involves ...endothelial dysfunction. Therefore, targeting re-epithelialization, which mainly involves keratinocytes, may improve therapeutic outcomes of current treatments. In this study, we present an integrin-binding prosurvival peptide derived from angiopoietin-1, QHREDGS (glutamine-histidine-arginine-glutamic acid-aspartic acid-glycine-serine), as a therapeutic candidate for diabetic wound treatments by demonstrating its efficacy in promoting the attachment, survival, and collective migration of human primary keratinocytes and the activation of protein kinase B Akt and MAPKp42/44. The QHREDGS peptide, both as a soluble supplement and when immobilized in a substrate, protected keratinocytes against hydrogen peroxide stress in a dose-dependent manner. Collective migration of both normal and diabetic human keratinocytes was promoted on chitosan–collagen films with the immobilized QHREDGS peptide. The clinical relevance was demonstrated further by assessing the chitosan–collagen hydrogel with immobilized QHREDGS in full-thickness excisional wounds in a db/db diabetic mouse model; QHREDGS showed significantly accelerated and enhanced wound closure compared with a clinically approved collagen wound dressing, peptide-free hydrogel, or blank wound controls. The accelerated wound closure resulted primarily from faster re-epithelialization and increased formation of granulation tissue. There were no observable differences in blood vessel density or size within the wound; however, the total number of blood vessels was greater in the peptide-hydrogel–treated wounds. Together, these findings indicate that QHREDGS is a promising candidate for wound-healing interventions that enhance re-epithelialization and the formation of granulation tissue.
Cell survival in complex, vascularized tissues, has been implicated as a major bottleneck in advancement of therapies based on cardiac tissue engineering. This limitation motivates the search for ...small, inexpensive molecules that would simultaneously be cardio-protective and vasculogenic. Here, we present peptide sequence QHREDGS, based upon the fibrinogen-like domain of angiopoietin-1, as a prime candidate molecule. We demonstrated previously that QHREDGS improved cardiomyocyte metabolism and mitigated serum starved apoptosis. In this paper we further demonstrate the potency of QHREDGS in its ability to enhance endothelial cell survival, metabolism and tube formation. When endothelial cells were exposed to the soluble form of QHREDGS, improvements in endothelial cell barrier functionality, nitric oxide production and cell metabolism (ATP levels) in serum starved conditions were found. The functionality of the peptide was then examined when conjugated to collagen-chitosan hydrogel, a potential carrier for in vivo application. The presence of the peptide in the hydrogel mitigated paclitaxel induced apoptosis of endothelial cells in a dose dependent manner. Furthermore, the peptide modified hydrogels stimulated tube-like structure formation of encapsulated endothelial cells. When integrin αvβ3 or α5β1 were antibody blocked during cell encapsulation in peptide modified hydrogels, tube formation was abolished. Therefore, the dual protective nature of the novel peptide QHREDGS may position this peptide as an appealing augmentation for collagen-chitosan hydrogels that could be used for biomaterial delivered cell therapies in the settings of myocardial infarction.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Myocardial infarction (MI) results in the death of cardiomyocytes (CM) followed by scar formation and pathological remodeling of the heart. We propose that chitosan conjugated with the angiopoietin-1 ...derived peptide, QHREDGS, and mixed with collagen I forms a thermoresponsive hydrogel better suited for the survival and maturation of transplanted cardiomyocytes in vitro compared to collagen and chitosan–collagen hydrogels alone. Conjugation of QHREDGS peptide to chitosan does not interfere with the gelation, structure or mechanical properties of the hydrogel blends. The storage modulus of 2.5mgml−1 1:1 mass:mass (m:m) chitosan–collagen was measured to be 54.9±9.1Pa, and the loss modulus 6.1±0.9Pa. The dose–response of the QHREDGS peptide was assessed and it was found that CMs encapsulated in High-peptide gel (651±8nmol peptide ml-gel−1) showed improved morphology, viability and metabolic activity in comparison to the Low-peptide (100±30nmol peptide ml-gel−1) and Control (No Peptide) groups. Construct (CMs in hydrogel) functional properties were not significantly different between the groups; however, the success rate of obtaining a beating construct was improved in the hydrogel with the High amount of QHREDGS peptide immobilized compared to the Low and Control groups. Subcutaneous injection of hydrogel (Control, Low and High) with CMs in the back of Lewis rats illustrated its ability to localize at the site of injection and retain cells, with CM contractile apparati identified after seven days. The hydrogel was also able to successfully localize at the site of injection in a mouse MI model.
Engineered cardiac tissues Iyer, Rohin K; Chiu, Loraine LY; Reis, Lewis A ...
Current opinion in biotechnology,
10/2011, Letnik:
22, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Highlights ► The review highlights recent advances in cardiac tissue engineering. ► We cover classical cell-scaffold approaches and advanced bioreactor designs. ► Cell sheet engineering and whole ...organ decellularization. ► Stem cell-based approaches and topographical control of tissue organization and function. ► Challenges in the field include stem cell control, maturation and tissue vascularization.
Thymosin β4 (Tβ4) is a peptide with multiple biological functions. Here, we focus on the role of Tβ4 in vascularization, and review our studies of the controlled delivery of Tβ4 through its ...incorporation in biomaterials. Tβ4 promotes vascularization through VEGF induction and AcSDKP‐induced migration and differentiation of endothelial cells. We developed a collagen–chitosan hydrogel for the controlled release of Tβ4 over 28 days. In vitro, the Tβ4‐encapsulated hydrogel increased migration of endothelial cells and tube formation from epicardial explants that were cultivated on top of the hydrogel, compared to Tβ4‐free hydrogel and soluble Tβ4 in the culture medium. In vivo, subcutaneously injected Tβ4‐containing collagen–chitosan hydrogel in rats led to enhanced vascularization compared to Tβ4‐free hydrogel and collagen hydrogel with Tβ4. Furthermore, the injection of the Tβ4‐encapsulated hydrogel in the infarct region improved angiogenesis, reduced tissue loss, and retained left ventricular wall thickness after myocardial infarction in rats.
We describe here a bioreactor capable of applying electrical field stimulation in conjunction with static strain and on-line force of contraction measurements. It consisted of a polydimethylsiloxane ...(PDMS) tissue chamber and a pneumatically driven stretch platform. The chamber contained eight tissue microwells (8.05 mm in length and 2.5 mm in width) with a pair of posts (2.78 mm in height and 0.8 mm in diameter) in each well to serve as fixation points and for measurements of contraction force. Carbon rods, stimulating electrodes, were placed into the PDMS chamber such that one pair stimulated four microwells. For feasibility studies, neonatal rat cardiomyocytes were seeded in collagen gels into the microwells. Following 3 days of gel compaction, electrical field stimulation at 3-4 V cm−1 and 1 Hz, mechanical stimulation of 5% static strain or electromechanical stimulation (field stimulation at 3-4 V cm−1, 1 Hz and 5% static strain) were applied for 3 days. Cardiac microtissues subjected to electromechanical stimulation exhibited elevated amplitude of contraction and improved sarcomere structure as evidenced by sarcomeric -actinin, actin and troponin T staining compared to microtissues subjected to electrical or mechanical stimulation alone or non-stimulated controls. The expression of atrial natriuretic factor and brain natriuretic peptide was also elevated in the electromechanically stimulated group.
Hydrogels are being actively investigated for direct delivery of cells or bioactive molecules to the heart after myocardial infarction (MI) to prevent cardiac functional loss. We postulate that ...immobilization of the prosurvival angiopoietin-1-derived peptide, QHREDGS, to a chitosan-collagen hydrogel could produce a clinically translatable thermoresponsive hydrogel to attenuate post-MI cardiac remodeling.
In a rat MI model, QHREDGS-conjugated hydrogel (QHG213H), control gel, or PBS was injected into the peri-infarct/MI zone. By in vivo tracking and chitosan staining, the hydrogel was demonstrated to remain in situ for 2 weeks and was cleared in ≈3 weeks. By echocardiography and pressure-volume analysis, the QHG213H hydrogel significantly improved cardiac function compared with the controls. Scar thickness and scar area fraction were also significantly improved with QHG213H gel injection compared with the controls. There were significantly more cardiomyocytes, determined by cardiac troponin-T staining, in the MI zone of the QHG213H hydrogel group; and hydrogel injection did not induce a significant inflammatory response as assessed by polymerase chain reaction and an inflammatory cytokine assay. The interaction of cardiomyocytes and cardiac fibroblasts with QHREDGS was found to be mediated by β1-integrins.
We demonstrated for the first time that the QHG213H peptide-modified hydrogel can be injected in the beating heart where it remains localized for a clinically effective period. Moreover, the QHG213H hydrogel induced significant cardiac functional and morphological improvements after MI relative to the controls.
Thymosin beta 4 (T beta 4) is a peptide with multiple biological functions. Here, we focus on the role of T beta 4 in vascularization, and review our studies of the controlled delivery of T beta 4 ...through its incorporation in biomaterials. T beta 4 promotes vascularization through VEGF induction and AcSDKP-induced migration and differentiation of endothelial cells. We developed a collagen-chitosan hydrogel for the controlled release of T beta 4 over 28 days. In vitro, the T beta 4-encapsulated hydrogel increased migration of endothelial cells and tube formation from epicardial explants that were cultivated on top of the hydrogel, compared to T beta 4-free hydrogel and soluble T beta 4 in the culture medium. In vivo, subcutaneously injected T beta 4-containing collagen-chitosan hydrogel in rats led to enhanced vascularization compared to T beta 4-free hydrogel and collagen hydrogel with T beta 4. Furthermore, the injection of the T beta 4-encapsulated hydrogel in the infarct region improved angiogenesis, reduced tissue loss, and retained left ventricular wall thickness after myocardial infarction in rats.
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