Tissue engineering of lymphatic vessel networks with nanofibre reinforced hydrogel constructs

The lymphatic system comprises tubular vessels which transport lymph back to the blood. Injury to the lymphatic vessels including surgery or radiation therapy during cancer therapy impairs lymphatic fluid transport, with the result that interstitial fluid accumulates causing oedema and inflammation. The lack of effective therapies to address these problems highlights the need to improve understanding of lymphatic vessel development and growth, which is key to the development of novel approaches to treat this debilitating condition. While regenerative medicine has the potential to resolve lympoedema through the reconstruction of a functional lymphatic microvasculature, the organisation of endothelial cells into capillaries remains a significant challenge. The interactions between migratory lymphatic endothelial cells (LECs) and surrounding extracellular matrix (ECM) are of central importance to microvessel formation. In the present study, hydrogels were employed to study lymphatic vessel development and maintenance in vitro. Further, a simple electrospinning set up comprising two parallel collectors was used to spin-coat aligned polymer fibres, representing the elastic fibre component of the ECM, over collagen hydrogels. The resulting fibre reinforced collagen gels have been employed here to study the growth, migration and vessel formation of lymphatic endothelial cells in vitro, with the aim of elucidating the initial steps of a functional lymphatic tissue, and to serve as a model of lymphedema for use in research.The lymphatic system comprises tubular vessels which transport lymph back to the blood. Injury to the lymphatic vessels including surgery or radiation therapy during cancer therapy impairs lymphatic fluid transport, with the result that interstitial fluid accumulates causing oedema and inflammation. The lack of effective therapies to address these problems highlights the need to improve understanding of lymphatic vessel development and growth, which is key to the development of novel approaches to treat this debilitating condition. While regenerative medicine has the potential to resolve lympoedema through the reconstruction of a functional lymphatic microvasculature, the organisation of endothelial cells into capillaries remains a significant challenge. The interactions between migratory lymphatic endothelial cells (LECs) and surrounding extracellular matrix (ECM) are of central importance to microvessel formation. In the present study, hydrogels were employed to study lymphatic vessel development and maintenance in vitro. Further, a simple electrospinning set up comprising two parallel collectors was used to spin-coat aligned polymer fibres, representing the elastic fibre component of the ECM, over collagen hydrogels. The resulting fibre reinforced collagen gels have been employed here to study the growth, migration and vessel formation of lymphatic endothelial cells in vitro, with the aim of elucidating the initial steps of a functional lymphatic tissue, and to serve as a model of lymphedema for use in research

Collagen–nanofiber hydrogel composites promote contact guidance of human lymphatic microvascular endothelial cells and directed capillary tube formation

Collagen and fibronectin matrices are known to stimulate migration of microvascular endothelial cells and the process of tubulogenesis, but the physical, chemical, and topographical cues for directed vessel formation have yet to be determined. In this study, growth, migration, elongation, and tube formation of human lymphatic microvascular endothelial cells (LECs) were investigated on electrospun poly(d,l-lactic-co-glycolic acid) (PLGA) and poly(l-lactic-co-d-lactic acid) (PLDL) nanofiber-coated substrates, and correlated with fiber density and diameter. Directed migration of LECs was observed in the presence of aligned nanofibers, whereas random fiber alignment slowed down migration and growth of LECs. Cell guidance was significantly enhanced in the presence of more hydrophobic PLDL polymer nanofibers compared to PLGA (10:90). Subsequent experiments with tube-forming assays reveal the ability of resorbable hydrophobic nanofibers >300 nm in diameter to promote cell guidance in collagen gels without direct cell–fiber contact, in contrast to the previously reported contact-guidance phenomena. Our results show that endothelial cell guidance is possible within nanofiber/collagen–gel constructs that mimic the native extracellular matrix in terms of size and orientation of fibrillar components

An Effect of Cyclosporin A in a Treatment of Temporal Bone Defect Using hBM-MSCs

Background. The treatment of middle ear cholesteatoma requires surgical treatment and the reconstruction of the temporal bone, which represents an ongoing problem. Otologists have focused on the research of materials allowing an airy middle ear and the preservation of hearing function to reconstruct the temporal bone. Methods. This study evaluated the effect of cyclosporin A (CsA) and a combined biomaterial in the healing process of postoperative temporal bone defects in an animal model. Cultured human Bone Marrow Mesenchymal Stromal Cells (hBM-MSCs) were mixed with hydroxyapatite (Cem-Ostetic®), and subsequently applied as a bone substitute after middle ear surgery, showing that the therapeutic potential of hBM-MSCs associated with bone regeneration and replacement is directly influenced by CsA, confirming that it promotes the survival of MSCs in vivo. Results. The therapeutic efficacy of the combination of MSCs with CsA is greater than the sole application of MSCs in a hydroxyapatite carrier. Conclusion. The reconstruction of a temporal bone defect using hBM-MSCs requires an immunosuppressant to improve the results of treatment

Clinicopathological Characteristics and Prognostic Factors in Ovarian Metastases from Right- and Left-Sided Colorectal Cancer

Background: Secondary tumors of the ovary (STOs) account for 10–25% of all ovarian malignancies, including metastases from primary gynecological tumors. Colorectal cancer (CRC) has been recognized as one of the most common causes of STOs in Western countries. Despite it being well-known that CRC originating from the right versus left side of the colon/rectum differ substantially, there is a paucity of information regarding the effect of the primary tumor sidedness on the clinicopathological characteristics of STOs. Methods: This retrospective, observational chart review study included patients with histologically confirmed STOs of CRC origin diagnosed between January 2000 and December 2019. The clinicopathological characteristics of STOs originating from left-sided and right-sided CRC were compared. Univariable and multivariable analyses employing elastic net Cox proportional hazard models were used to evaluate potential prognostic factors. Further, the role of imaging methods in STOs diagnostics was evaluated. Results: Fifty-one patients with STOs of colorectal origin were identified. The primary tumor originated in the right and left colon/rectum in 39% and 61% of the cases, respectively. STOs originating from right-sided primary tumors were more frequently bilateral, associated with peritoneal carcinomatosis, had the ovarian surface affected by the tumor, and contained a mucinous component. The independent prognostic factors for overall survival in the whole cohort included: the presence of macroscopic residual disease after cytoreductive surgery, menopausal status, the application of systemic therapy, and the application of targeted therapy. In 54% of cases, the imaging methods failed to determine the laterality of the STOs correctly as compared to pathological reports and/or intraoperative findings. Conclusion: STOs originating from left-sided and right-sided CRC show distinct clinicopathological characteristics. Moreover, different metastatic pathways might be employed according to the primary tumor sidedness. Considering the discrepancies between radiological assessment and histopathological findings regarding the laterality of STOs, bilateral adnexectomy should be advised whenever feasible

Human Multipotent Mesenchymal Stromal Cells in the Treatment of Postoperative Temporal Bone Defect: An Animal Model

International audienceCanal wall down mastoidectomy is one of the most effective treatments for cholesteatoma. However, it results in anatomical changes in the external and middle ear with a negative impact on the patient's quality of life. To provide complete closure of the mastoid cavity and normalize the anatomy of the middle and external ear, we used human multipotent mesenchymal stromal cells (hMSCs), GMP grade, in a guinea pig model. A method for preparing a biomaterial composed of hMSCs, hydroxyapatite, and tissue glue was developed. Animals from the treated group were implanted with biomaterial composed of hydroxyapatite and hMSCs, while animals in the control group received hydroxyapatite alone. When compared to controls, the group implanted with hMSCs showed a significantly higher ratio of new bone formation (p = 0.00174), as well as a significantly higher volume percentage of new immature bone (p = 0.00166). Our results proved a beneficial effect of hMSCs on temporal bone formation and provided a promising tool to improve the quality of life of patients after canal wall down mastoidectomy by hMSC implantation

Selection of human induced pluripotent stem cells lines optimization of cardiomyocytes differentiation in an integrated suspension microcarrier bioreactor

10.1186/s13287-020-01618-6STEM CELL RESEARCH & THERAPY11

Cardiomyocyte differentiation of pluripotent stem cells with SB203580 analogues correlates with Wnt pathway CK1 inhibition independent of p38 MAPK signaling

10.1016/j.yjmcc.2014.12.003Journal of Molecular and Cellular Cardiology8056-7