Functional regeneration of laryngeal muscle using bone marrow-derived stromal cells

Bone Marrow-Mesenchymal Stromal Cell Secretome as Conditioned Medium Relieves Experimental Skeletal Muscle Damage Induced by Ex Vivo Eccentric Contraction

Bone marrow-mesenchymal stem/stromal cells (MSCs) may offer promise for skeletal muscle repair/regeneration. Growing evidence suggests that the mechanisms underpinning the beneficial effects of such cells in muscle tissue reside in their ability to secrete bioactive molecules (secretome) with multiple actions. Hence, we examined the effects of MSC secretome as conditioned medium (MSC-CM) on ex vivo murine extensor digitorum longus muscle injured by forced eccentric contraction (EC). By combining morphological (light and confocal laser scanning microscopies) and electrophysiological analyses we demonstrated the capability of MSC-CM to attenuate EC-induced tissue structural damages and sarcolemnic functional properties’ modifications. MSC-CM was effective in protecting myofibers from apoptosis, as suggested by a reduced expression of pro-apoptotic markers, cytochrome c and activated caspase-3, along with an increase in the expression of pro-survival AKT factor. Notably, MSC-CM also reduced the EC-induced tissue redistribution and extension of telocytes/CD34⁺ stromal cells, distinctive cells proposed to play a “nursing” role for the muscle resident myogenic satellite cells (SCs), regarded as the main players of regeneration. Moreover, it affected SC functionality likely contributing to replenishment of the SC reservoir. This study provides the necessary groundwork for further investigation of the effects of MSC secretome in the setting of skeletal muscle injury and regenerative medicine.

Extracellular Matrix for Vocal Fold Lamina Propria Replacement: A Review

The vocal folds (VFs) are exposed to a number of injurious stimuli that frequently lead to aberrant structural alterations and altered biomechanical properties that clinically manifest as voice disorders. Therapies to restore both structure and function of this delicate tissue are ideal. However, such methods have not been adequately developed. Our group and others hypothesize that tissue engineering and regenerative medicine approaches, previously described for other tissue systems, hold significant promise for the VFs. In this review, we explore the concept of tissue engineering as it relates to the VFs, as well as recent studies employing both naturally and synthetically derived biomaterials, including those from laryngeal and nonlaryngeal sources, in combination with stem cells for a tissue-engineered approach to VF repair.

Stem cell approaches for vocal fold regeneration

OBJECTIVES/HYPOTHESIS

Current interventions in the management of vocal fold (VF) dysfunction focus on conservative and surgical approaches. However, the complex structure and precise biomechanical properties of the human VF mean that these strategies have their limitations in clinical practice and in some cases offer inadequate levels of success. Regenerative medicine is an exciting development in this field and has the potential to further enhance VF recovery beyond conventional treatments. Our aim in this review is to discuss advances in the field of regenerative medicine; that is, advances in the process of replacing, engineering, or regenerating the VF through utilization of stem cells, with the intention of restoring normal VF structure and function.

DATA SOURCES

English literature (1946-2015) review.

METHODS

We conducted a systematic review of MEDLINE for cases and studies of VF tissue engineering utilizing stem cells.

RESULTS

The three main approaches by which regenerative medicine is currently applied to VF regeneration include cell therapy, scaffold development, and utilization of growth factors.

CONCLUSION

Exciting advances have been made in stem cell biology in recent years, including use of induced pluripotent stem cells. We expect such advances to be translated into the field in the forthcoming years. Laryngoscope, 126:1865-1870, 2016.

Mesenchymal stromal cell secreted sphingosine 1-phosphate (S1P) exerts a stimulatory effect on skeletal myoblast proliferation

Bone-marrow-derived mesenchymal stromal cells (MSCs) have the potential to significantly contribute to skeletal muscle healing through the secretion of paracrine factors that support proliferation and enhance participation of the endogenous muscle stem cells in the process of repair/regeneration. However, MSC-derived trophic molecules have been poorly characterized. The aim of this study was to investigate paracrine signaling effects of MSCs on skeletal myoblasts. It was found, using a biochemical and morphological approach that sphingosine 1-phosphate (S1P), a natural bioactive lipid exerting a broad range of muscle cell responses, is secreted by MSCs and represents an important factor by which these cells exert their stimulatory effects on C2C12 myoblast and satellite cell proliferation. Indeed, exposure to conditioned medium obtained from MSCs cultured in the presence of the selective sphingosine kinase inhibitor (iSK), blocked increased cell proliferation caused by the conditioned medium from untreated MSCs, and the addition of exogenous S1P in the conditioned medium from MSCs pre-treated with iSK further increased myoblast proliferation. Finally, we also demonstrated that the myoblast response to MSC-secreted vascular endothelial growth factor (VEGF) involves the release of S1P from C2C12 cells. Our data may have important implications in the optimization of cell-based strategies to promote skeletal muscle regeneration.

Airway tissue engineering: an update

INTRODUCTION

Prosthetic materials, autologous tissues, cryopreserved homografts and allogeneic tissues have thus far proven unsuccessful in providing long-term functional solutions to extensive upper airway disease and damage. Research is therefore focusing on the rapidly expanding fields of regenerative medicine and tissue engineering in order to provide stem cell-based constructs for airway reconstruction, substitution and/or regeneration.

AREAS COVERED

Advances in stem cell technology, biomaterials and growth factor interactions have been instrumental in guiding optimization of tissue-engineered airways, leading to several first-in-man studies investigating stem cell-based tissue-engineered tracheal transplants in patients. Here, we summarize current progress, outstanding research questions, as well as future directions within the field.

EXPERT OPINION

The complex immune interaction between the transplant and host in vivo is only beginning to be untangled. Recent progress in our understanding of stem cell biology, decellularization techniques, biomaterials and transplantation immunobiology offers the prospect of transplanting airways without the need for lifelong immunosuppression. In addition, progress in airway revascularization, reinnervation and ever-increasingly sophisticated bioreactor design is opening up new avenues for the construction of a tissue-engineered larynx. Finally, 3D printing is a novel technique with the potential to render microscopic control over how cells are incorporated and grown onto the tissue-engineered airway.

Stem cell-based organ replacements-airway and lung tissue engineering

Tissue engineering requires the use of cells seeded onto scaffolds, often in conjunction with bioactive molecules, to regenerate or replace tissues. Significant advances have been made in recent years within the fields of stem cell biology and biomaterials, leading to some exciting developments in airway tissue engineering, including the first use of stem cell-based tissue-engineered tracheal replacements in humans. In addition, recent advances within the fields of scaffold biology and decellularization offer the potential to transplant patients without the use of immunosuppression.