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Metabolic Glycoengineering: A Promising Strategy to Remodel Microenvironments for Regenerative Therapy. Stem Cells Int 2023; 2023:1655750. [PMID: 36814525 PMCID: PMC9940976 DOI: 10.1155/2023/1655750] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 09/27/2022] [Accepted: 01/17/2023] [Indexed: 02/15/2023] Open
Abstract
Cell-based regenerative therapy utilizes the differentiation potential of stem cells to rejuvenate tissues. But the dynamic fate of stem cells is calling for precise control to optimize their therapeutic efficiency. Stem cell fate is regulated by specific conditions called "microenvironments." Among the various factors in the microenvironment, the cell-surface glycan acts as a mediator of cell-matrix and cell-cell interactions and manipulates the behavior of cells. Herein, metabolic glycoengineering (MGE) is an easy but powerful technology for remodeling the structure of glycan. By presenting unnatural glycans on the surface, MGE provides us an opportunity to reshape the microenvironment and evoke desired cellular responses. In this review, we firstly focused on the determining role of glycans on cellular activity; then, we introduced how MGE influences glycosylation and subsequently affects cell fate; at last, we outlined the application of MGE in regenerative therapy, especially in the musculoskeletal system, and the future direction of MGE is discussed.
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McGuinness MB, Kasza J, Wu Z, Guymer RH. Focus on Survival Analysis for Eye Research. Invest Ophthalmol Vis Sci 2021; 62:7. [PMID: 33950248 PMCID: PMC8107496 DOI: 10.1167/iovs.62.6.7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Analysis of time-to-event data, otherwise known as survival analysis, is a common investigative tool in ophthalmic research. For example, time-to-event data is useful when researchers are interested in investigating how long it takes for an ocular condition to worsen or whether treatment can delay the development of a potentially vision-threatening complication. Its implementation requires a different set of statistical tools compared to those required for analyses of other continuous and categorial outcomes. In this installment of the Focus on Data series, we present an overview of selected concepts relating to analysis of time-to-event data in eye research. We introduce censoring, model selection, consideration of model assumptions, and best practice for reporting. We also consider challenges that commonly arise when analyzing time-to-event data in ophthalmic research, including collection of data from two eyes per person and the presence of multiple outcomes of interest. The concepts are illustrated using data from the Laser Intervention in Early Stages of Age-Related Macular Degeneration study and statistical computing code for Stata is provided to demonstrate the application of the statistical methods to illustrative data.
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Affiliation(s)
- Myra B McGuinness
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.,Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia
| | - Jessica Kasza
- School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia
| | - Zhichao Wu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Australia
| | - Robyn H Guymer
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Australia
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Du J, Chen H, Qing L, Yang X, Jia X. Biomimetic neural scaffolds: a crucial step towards optimal peripheral nerve regeneration. Biomater Sci 2018; 6:1299-1311. [PMID: 29725688 PMCID: PMC5978680 DOI: 10.1039/c8bm00260f] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Peripheral nerve injury is a common disease that affects more than 20 million people in the United States alone and remains a major burden to society. The current gold standard treatment for critical-sized nerve defects is autologous nerve graft transplantation; however, this method is limited in many ways and does not always lead to satisfactory outcomes. The limitations of autografts have prompted investigations into artificial neural scaffolds as replacements, and some neural scaffold devices have progressed to widespread clinical use; scaffold technology overall has yet to be shown to be consistently on a par with or superior to autografts. Recent advances in biomimetic scaffold technologies have opened up many new and exciting opportunities, and novel improvements in material, fabrication technique, scaffold architecture, and lumen surface modifications that better reflect biological anatomy and physiology have independently been shown to benefit overall nerve regeneration. Furthermore, biomimetic features of neural scaffolds have also been shown to work synergistically with other nerve regeneration therapy strategies such as growth factor supplementation, stem cell transplantation, and cell surface glycoengineering. This review summarizes the current state of neural scaffolds, highlights major advances in biomimetic technologies, and discusses future opportunities in the field of peripheral nerve regeneration.
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Affiliation(s)
- Jian Du
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA. ; Tel: +1 410-706-5025
| | - Huanwen Chen
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA. ; Tel: +1 410-706-5025
| | - Liming Qing
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA. ; Tel: +1 410-706-5025
| | - Xiuli Yang
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA. ; Tel: +1 410-706-5025
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA. ; Tel: +1 410-706-5025
- Department of Orthopedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Koulaxouzidis G, Reutter W, Witzel C. N-Propionylmannosamine: using biochemical glycoengineering to promote peripheral nerve regeneration. Neural Regen Res 2016; 10:1947-8. [PMID: 26889181 PMCID: PMC4730817 DOI: 10.4103/1673-5374.169616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Georgios Koulaxouzidis
- Department of Plastic and Hand Surgery, University of Freiburg Medical Center, Freiburg, Germany
| | - Werner Reutter
- Institut für Laboratoriumsmedizin, Klinische Chemie und Pathobiochemie Charité-Universitätsmedizin (Freie Universität Berlin), Berlin-Dahlem, Germany
| | - Christian Witzel
- Plastic and Reconstructive Surgery, Charité-Universitätsmedizin Berlin, Germany
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Koulaxouzidis G, Reim G, Witzel C. Fibrin glue repair leads to enhanced axonal elongation during early peripheral nerve regeneration in an in vivo mouse model. Neural Regen Res 2015; 10:1166-71. [PMID: 26330844 PMCID: PMC4541252 DOI: 10.4103/1673-5374.156992] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2015] [Indexed: 11/04/2022] Open
Abstract
Microsurgical suturing is the gold standard of nerve coaptation. Although literature on the usefulness of fibrin glue as an alternative is becoming increasingly available, it remains contradictory. Furthermore, no data exist on how both repair methods might influence the morphological aspects (arborization; branching) of early peripheral nerve regeneration. We used the sciatic nerve transplantation model in thy-1 yellow fluorescent protein mice (YFP; n = 10). Pieces of nerve (1cm) were grafted from YFP-negative mice (n = 10) into those expressing YFP. We performed microsuture coaptations on one side and used fibrin glue for repair on the contralateral side. Seven days after grafting, the regeneration distance, the percentage of regenerating and arborizing axons, the number of branches per axon, the coaptation failure rate, the gap size at the repair site and the time needed for surgical repair were all investigated. Fibrin glue repair resulted in regenerating axons travelling further into the distal nerve. It also increased the percentage of arborizing axons. No coaptation failure was detected. Gap sizes were comparable in both groups. Fibrin glue significantly reduced surgical repair time. The increase in regeneration distance, even after the short period of time, is in line with the results of others that showed faster axonal regeneration after fibrin glue repair. The increase in arborizing axons could be another explanation for better functional and electrophysiological results after fibrin glue repair. Fibrin glue nerve coaptation seems to be a promising alternative to microsuture repair.
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Affiliation(s)
- Georgios Koulaxouzidis
- Department of Plastic and Hand Surgery, University of Freiburg Medical Centre, Freiburg, Germany
| | - Gernot Reim
- Department of Plastic and Hand Surgery, University of Freiburg Medical Centre, Freiburg, Germany
| | - Christian Witzel
- Plastic and Reconstructive Surgery – Interdisciplinary Breast Center, Charité – Universitätsmedizin Berlin, Germany
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Koulaxouzidis G, Reutter W, Hildebrandt H, Stark GB, Witzel C. In vivo stimulation of early peripheral axon regeneration by N-propionylmannosamine in the presence of polysialyltransferase ST8SIA2. J Neural Transm (Vienna) 2015; 122:1211-9. [PMID: 25850639 DOI: 10.1007/s00702-015-1397-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Accepted: 03/25/2015] [Indexed: 01/19/2023]
Abstract
The key enzyme of sialic acid (Sia) biosynthesis is the bifunctional UDP-N-acetylglucosamine 2-epimerase/ManNAc kinase (GNE/MNK). It metabolizes the physiological precursor ManNAc and N-acyl modified analogues such as N-propionylmannosamine (ManNProp) to the respective modified sialic acid. Polysialic acid (polySia) is a crucial compound for several functions in the nervous system and is synthesized by the polysialyltransferases ST8SIA2 and ST8SIA4. PolySia can be modified in vitro and in vivo by metabolic glycoengineering of the N-acyl side chain of Sia. In vitro studies show that the application of ManNProp increases neurite outgrowth and accelerates the re-establishment of functional synapses. In this study, we investigate in vivo how ManNProp application might benefit peripheral nerve regeneration. In mice expressing axonal fluorescent proteins (thy-1-YFP), we transected the sciatic nerve and then replaced part of it with a sciatic nerve graft from non-expressing mice (wild-type mice or St8sia2(-/-) mice). Analyses conducted 5 days after grafting showed that systemic application of ManNProp (200 mg/kg, twice a day, i.p.), but not of physiological ManNAc (1 g/kg, twice a day, i.p.), significantly increased the extent of axonal elongation, the number of arborizing axons and the number of branches per regenerating axon within the grafts from wild-type mice, but not in those from St8sia2(-/-) mice. The results demonstrate that the application of ManNProp has beneficial effects on early peripheral nerve regeneration and indicate that the stimulation of axon growth depends on ST8SIA2 activity in the nerve graft.
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Affiliation(s)
- Georgios Koulaxouzidis
- Klinik für Plastische und Handchirurgie, Universitätsklinikum Freiburg, Freiburg, Germany,
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