Are bone marrow regenerative cells ideal seed cells for the treatment of cerebral ischemia?

Bone marrow cells for the treatment of ischemic brain injury may depend on the secretion of a large number of neurotrophic factors. Bone marrow regenerative cells are capable of increasing the secretion of neurotrophic factors. In this study, after tail vein injection of 5-fluorouracil for 7 days, bone marrow cells and bone marrow regenerative cells were isolated from the tibias and femurs of rats, and then administered intravenously via the tail vein after focal cerebral ischemia. Immunohistological staining and reverse transcription-PCR detection showed that transplanted bone marrow cells and bone marrow regenerative cells could migrate and survive in the ischemic regions, such as the cortical and striatal infarction zone. These cells promote vascular endothelial cell growth factor mRNA expression in the ischemic marginal zone surrounding the ischemic penumbra of the cortical and striatal infarction zone, and have great advantages in promoting the recovery of neurological function, reducing infarct size and promoting angiogenesis. Bone marrow regenerative cells exhibited stronger neuroprotective effects than bone marrow cells. Our experimental findings indicate that bone marrow regenerative cells are preferable over bone marrow cells for cell therapy for neural regeneration after cerebral ischemia. Their neuroprotective effect is largely due to their ability to induce the secretion of factors that promote vascular regeneration, such as vascular endothelial growth factor.

Olfactory ensheathing cell transplantation for spinal cord injury An 18-year bibliometric analysis based on the Web of Science

OBJECTIVE： Olfactory ensheathing cell （OEC） transplantation is a promising new approach for the treatment of spinal cord injury （SCI）, and an increasing number of scientific publications are devoted to this treatment strategy. This bibliometric analysis was conducted to assess global research trends in OEC transplantation for SCI. DATA SOURCE： All of the data in this study originate from the Web of Science maintained by the Institute for Scientific Information, USA, and includes SCI-EXPANDED, SSCI, A＆HCI, CPCI-S, CPCI-SSH, BKCI-S, BKCI-SSH, CCR-EXPANDED and IC. The Institute for Scientific Information＇s Web of Science was searched using the keywords ＂olfactory ensheathing cells＂ or ＂OECs＂ or ＂olfactory ensheathing gila＂ or ＂OEG＂ or ＂olfactory ensheathing glial cells＂ or ＂OEGs＂ and ＂spinal cord injury＂ or ＂SCI＂ or ＂spinal injury＂ or ＂spinal transection＂ for literature published from January 1898 to May 2012. DATA SELECTION： Original articles, reviews, proceedings papers and meeting abstracts, book chapters and editorial materials on OEC transplantation for SCI were included. Simultaneously, unpublished literature and literature for which manual information retrieval was required were excluded. MAIN OUTCOME MEASURES： All selected literatures addressing OEC transplantation for SCI were evaluated in the following aspects： publication year, document type, language, author, institution, times cited, Web of Science category, core source title, countries/territories and funding agency.RESULTS： In the Web of Science published by the Institute for Scientific Information, the earliest literature record was in April, 1995. Four hundred and fourteen publications addressing OEC transplantation for SCI were added to the data library in the past 18 years, with an annually increasing trend. Of 415 records, 405 publications were in English. Two hundred and fifty-nine articles ranked first in the distribution of document type, followed by 141 reviews. Thirty articles and 20 reviews, cited more than 55 times by the date the publication data were downloaded by us, can be regarded as the most classical references. The journal Experimental Neurology published the most literature （32 records）, followed by Glia. The United States had the most literature, followed by China. In addition, Yale University was the most productive institution in the world, while The Second Military Medical University contributed the most in China. The journal Experimental Neurology published the most OEC transplantation literature in the United States, while Neural Regeneration Research published the most in China. CONCLUSION： This analysis provides insight into the current state and trends in OEC transplantation for SCI research. Furthermore, we anticipate that this analysis will help encourage international cooperation and teamwork on OEC transplantation for SCI to facilitate the development of more effective treatments for SCI.

Status and developmental trends in recombinant collagen preparation technology

Recombinant collagen is a pivotal topic in foundational biological research and epitomizes the application of critical bioengineer-ing technologies.These technological advancements have pro-found implications across diverse areas such as regenerative medicine,organ replacement,tissue engineering,cosmetics and more.Thus,recombinant collagen and its preparation methodologies rooted in genetically engineered celis mark pivotal milestones in medical product research.This article pro-vides a comprehensive overview of the current genetic engi-neering technologies and methods used in the production of recombinant collagen,as well as the conventional production process and gquality control detection methods for this material.Furthermore,the discussion extends to foresee the strides in physical transfection and magnetic control sorting studies,envisioning an enhanced preparation of recombinant collagen-seeded cells to further fuel recombinant collagen production.

Application of stem cells in peripheral nerve regeneration

Traumatic peripheral nerve injury is a worldwide clinical issue with high morbidity.The severity of peripheral nerve injury can be classified as neurapraxia,axonotmesis or neurotmesis,according to Seddon’s classification,or five different degrees according to Sunderland’s classification.Patients with neurotmesis suffer from a complete transection of peripheral nerve stumps and are often in need of surgical repair of nerve defects.The applications of autologous nerve grafts as the golden standard for peripheral nerve transplantation meet some difficulties,including donor nerve sacrifice and nerve mismatch.Attempts have been made to construct tissue-engineered nerve grafts as supplements or even substitutes for autologous nerve grafts to bridge peripheral nerve defects.The incorporation of stem cells as seed cells into the biomaterial-based scaffolds increases the effectiveness of tissue-engineered nerve grafts and largely boosts the regenerative process.Numerous stem cells,including embryonic stem cells,neural stem cells,bone marrow mesenchymal stem cells,adipose stem cells,skin-derived precursor stem cells and induced pluripotent stem cells,have been used in neural tissue engineering.In the current review,recent trials of stem cell-based tissue-engineered nerve grafts have been summarized;potential concerns and perspectives of stem cell therapeutics have also been contemplated.

Current progress of skin tissue engineering:Seed cells, bioscaffolds, and construction strategies

The development of cell biology, molecular biology, and material science, has been propelling biomimic tissue-engineered skins to become more sophisticated in scientificity and more simplified in practicality. In order to improve the safety, durability, elasticity, biocompatibility, and clinical efficacy of tissue-engineered skin, several powerful seed cells have already found their application in wound repair, and a variety of bioactive scaffolds have been discovered to influence cell fate in epidermogenesis. These exuberant interests provide insights into advanced construction strategies for complex skin mimics. Based on these exciting developments, a complete full-thickness tissue-engineered skin is likely to be generated.

3D printed silk-gelatin hydrogel scaffold with different porous structure and cell seeding strategy for cartilage regeneration

Hydrogel scaffolds are attractive for tissue defect repair and reorganization because of their human tissue-like characteristics.However,most hydrogels offer limited cell growth and tissue formation ability due to their submicron-or nano-sized gel networks,which restrict the supply of oxygen,nutrients and inhibit the proliferation and differentiation of encapsulated cells.In recent years,3D printed hydrogels have shown great potential to overcome this problem by introducing macro-pores within scaffolds.In this study,we fabricated a macroporous hydrogel scaffold through horseradish peroxidase(HRP)-mediated crosslinking of silk fibroin(SF)and tyramine-substituted gelatin(GT)by extrusion-based low-temperature 3D printing.Through physicochemical characterization,we found that this hydrogel has excellent structural stability,suitable mechanical properties,and an adjustable degradation rate,thus satisfying the requirements for cartilage reconstruction.Cell suspension and aggregate seeding methods were developed to assess the inoculation efficiency of the hydrogel.Moreover,the chondrogenic differentiation of stem cells was explored.Stem cells in the hydrogel differentiated into hyaline cartilage when the cell aggregate seeding method was used and into fibrocartilage when the cell suspension was used.Finally,the effect of the hydrogel and stem cells were investigated in a rabbit cartilage defect model.After implantation for 12 and 16 weeks,histological evaluation of the sections was performed.We found that the enzymatic cross-linked and methanol treatment SF5GT15 hydrogel combined with cell aggregates promoted articular cartilage regeneration.In summary,this 3D printed macroporous SF-GT hydrogel combined with stem cell aggregates possesses excellent potential for application in cartilage tissue repair and regeneration.

Selection of different endothelialization modes and different seed cells for tissue-engineered vascular graft

Tissue-engineered vascular grafts(TEVGs)have enormous potential for vascular replacement therapy.However,thrombosis and intimal hyperplasia are important problems associated with TEVGs especially small diameter TEVGs(<6 mm)after transplantation.Endothelialization of TEVGs is a key point to prevent thrombosis.Here,we discuss different types of endothelialization and different seed cells of tissue-engineered vascular grafts.Meanwhile,endothelial heterogeneity is also discussed.Based on it,we provide a new perspective for selecting suitable types of endothelialization and suitable seed cells to improve the long-term patency rate of tissue-engineered vascular grafts with different diameters and lengths.