Umbilical Cord Tissue-Derived Cells as Therapeutic Agents

Cryopreservation: A Comprehensive Overview, Challenges, and Future Perspectives

Cryopreservation is the most prevalent method of long-term cell preservation. Effective cell cryopreservation depends on freezing, adequate storage, and correct thawing techniques. Recent advances in cryopreservation techniques minimize the cellular damage which occurs while processing samples. This article focuses on the fundamentals of cryopreservation techniques and how they can be implemented in a variety of clinical settings. The article presents a brief description of each of the standard cryopreservation procedures, such as slow freezing and vitrification. Alongside that, the membrane permeating and nonpermeating cryoprotectants are briefly discussed, along with current advancements in the field of cryopreservation and variables influencing the cryopreservation process. The diminution of cryoinjury incurred by the cell via the resuscitation process will also be highlighted. In the end application of cryopreservation techniques in many fields, with a special emphasis on stem cell preservation techniques and current advancements presented. Furthermore, the challenges while implementing cryopreservation and the futuristic scope of the fields are illustrated herein. The content of this review sheds light on various ways to enhance the output of the cell preservation process and minimize cryoinjury while improving cell revival.

Lipid bilayers as potential ice nucleating agents

Cellular damage is a key issue in the context of cryopreservation. Much of this damage is believed to be caused by extracellular ice formation at temperatures well above the homogeneous freezing point of pure water. Hence the question: what initiates ice nucleation during cryopreservation? In this paper, we assess whether cellular membranes could be responsible for facilitating the ice nucleation process, and what characteristics would make them good or bad ice nucleating agents. By means of molecular dynamics simulations, we investigate a number of phospholipids and lipopolysaccharide bilayers at the interface with supercooled liquid water. While these systems certainly appear to act as ice nucleating agents, it is likely that other impurities might also play a role in initiating extracellular ice nucleation. Furthermore, we elucidate the factors which affect a bilayer's ability to act as an ice nucleating agent; these are complex, with specific reference to both chemical and structural factors. These findings represent a first attempt to pinpoint the origin of extracellular ice nucleation, with important implications for the cryopreservation process.

OUP accepted manuscript

Cord blood (CB) collected at birth has become a valuable stem cell source for hematopoietic stem cell transplantation (HSCT). However, the collection of umbilical cord blood always bears a risk of microbiological contamination, both in vaginal birth and in cesarean section. A total of 10 054 umbilical cord stem cell samples were successfully cryopreserved between 2010 and 2020, of which 783 (8%) samples were tested positive for bacterial contamination. Umbilical CB with a volume of less than 60 mL showed a bacterial contamination rate of 12%, and above 60 mL volume a rate of 6% was found demonstrating an inverse relationship between sample volume and contamination rate (correlation coefficient r = −0.9). The contamination rate was associated with the mode of delivery and showed a significantly higher contamination rate of 9.7% when compared with cesarean deliveries (1.4%). The 10-year period consistently shows an average contamination rate between 4% and 6% per year. It is conceivable that the inverse relationship between volume and contamination rate might be related to thinner veins although no scientific evidence has been provided so far. The lower contamination rate in cesarean sections appears to be related to the sterile operating setting. Overall, the rate of bacterial contamination varies and depends on the type of birth, the way of delivery, and probably the experience of the staff.

Human Mesenchymal Stem Cells Seeded on the Natural Membrane to Neurospheres for Cholinergic-like Neurons

This study aimed to differentiate human mesenchymal stem cells (hMSCs) from the human umbilical cord in cholinergic-like neurons using a natural membrane. The isolation of hMSCs from Wharton’s jelly (WJ) was carried out using “explant” and mononuclear cells by the density gradient from umbilical blood and characterized by flow cytometry. hMSCs were seeded in a natural functional biopolymer membrane to produce neurospheres. RT-PCR was performed on hMSCs and neurospheres derived from the umbilical cord. Neural precursor cells were subjected to a standard cholinergic-like neuron differentiation protocol. Dissociated neurospheres, neural precursor cells, and cholinergic-like neurons were characterized by immunocytochemistry. hMSCs were CD73+, CD90+, CD105+, CD34- and CD45- and demonstrated the trilineage differentiation. Neurospheres and their isolated cells were nestin-positive and expressed NESTIN, MAP2, ßIII-TUBULIN, GFAP genes. Neural precursor cells that were differentiated in cholinergic-like neurons expressed ßIII-TUBULIN protein and choline acetyltransferase enzyme. hMSCs seeded on the natural membrane can differentiate into neurospheres, obtaining neural precursor cells without growth factors or gene transfection before cholinergic phenotype differentiation.

Uncovering the Diversification of Tissue Engineering on the Emergent Areas of Stem Cells, Nanotechnology and Biomaterials

Damaged or disabled tissue is life-threatening due to the lack of proper treatment. Many conventional transplantation methods like autograft, iso-graft and allograft are in existence for ages, but they are not sufficient to treat all types of tissue or organ damages. Stem cells, with their unique capabilities like self-renewal and differentiate into various cell types, can be a potential strategy for tissue regeneration. However, the challenges like reproducibility, uncontrolled propagation and differentiation, isolation of specific kinds of cell and tumorigenic nature made these stem cells away from clinical application. Today, various types of stem cells like embryonic, fetal or gestational tissue, mesenchymal and induced-pluripotent stem cells are under investigation for their clinical application. Tissue engineering helps in configuring the stem cells to develop into a desired viable tissue, to use them clinically as a substitute for the conventional method. The use of stem cell-derived Extracellular Vesicles (EVs) is being studied to replace the stem cells, which decreases the immunological complications associated with the direct administration of stem cells. Tissue engineering also investigates various biomaterials to use clinically, either to replace the bones or as a scaffold to support the growth of stemcells/ tissue. Depending upon the need, there are various biomaterials like bio-ceramics, natural and synthetic biodegradable polymers to support replacement or regeneration of tissue. Like the other fields of science, tissue engineering is also incorporating the nanotechnology to develop nano-scaffolds to provide and support the growth of stem cells with an environment mimicking the Extracellular matrix (ECM) of the desired tissue. Tissue engineering is also used in the modulation of the immune system by using patient-specific Mesenchymal Stem Cells (MSCs) and by modifying the physical features of scaffolds that may provoke the immune system. This review describes the use of various stem cells, biomaterials and the impact of nanotechnology in regenerative medicine.

Stem cell therapy: old challenges and new solutions

Stem cell therapy (SCT), born as therapeutic revolution to replace pharmacological treatments, remains a hope and not yet an effective solution. Accordingly, stem cells cannot be conceivable as a "canonical" drug, because of their unique biological properties. A new reorientation in this field is emerging, based on a better understanding of stem cell biology and use of cutting-edge technologies and innovative disciplines. This will permit to solve the gaps, failures, and long-term needs, such as the retention, survival and integration of stem cells, by employing pharmacology, genetic manipulation, biological or material incorporation. Consequently, the clinical applicability of SCT for chronic human diseases will be extended, as well as its effectiveness and success, leading to long-awaited medical revolution. Here, some of these aspects are summarized, reviewing and discussing recent advances in this rapidly developing research field.

Cell Therapy-a Basic Science Primer for the Sports Medicine Clinician

PURPOSE OF REVIEW

The emergence of cell-based therapies has brought much excitement to the field of orthopedic sports medicine. However, the significant inconsistency of reporting has led to the poor understanding, misinformation, and false expectations for patients and clinicians alike. In this paper, we aim to clarify the available cell-therapy treatments and summarize some of the latest research.

RECENT FINDINGS

Although this technology is in early development, our understanding of cell biology has grown significantly over the last decade. Furthermore, it is becoming evident that tissue specificity may play a significant role in determining the effectiveness and overall clinical benefit attributed to cell therapy. Cell therapy is an emerging field with tremendous potential for clinically significant benefit. However, in its current state, clinical application of these treatments is limited by federal regulations, variability in formulation, and limited understanding of the biologic activity of various cell formulations.

Umbilical cord-derived mesenchymal stromal cells in cardiovascular disease: review of preclinical and clinical data

The human umbilical cord has recently emerged as an attractive potential source of mesenchymal stromal cells (MSCs) to be adopted for use in regenerative medicine. Umbilical cord MSCs (UC-MSCs) not only share the same features of all MSCs such as multi-lineage differentiation, paracrine functions and immunomodulatory properties, they also have additional advantages, such as no need for bone marrow aspiration and higher self-renewal capacities. They can be isolated from various compartments of the umbilical cord (UC) and can be used for autologous or allogeneic purposes. In the past decade, they have been adopted in cardiovascular disease and have shown promising results mainly due to their pro-angiogenic and anti-inflammatory properties. This review offers an overview of the biological properties of UC-MSCs describing available pre-clinical and clinical data with respect to their potential therapeutic use in cardiovascular regeneration, with current challenges and future directions discussed.

A multicentre prospective randomised controlled comparative parallel study of dehydrated human umbilical cord (EpiCord) allograft for the treatment of diabetic foot ulcers

The aim of this study was to determine the safety and effectiveness of dehydrated human umbilical cord allograft (EpiCord) compared with alginate wound dressings for the treatment of chronic, non‐healing diabetic foot ulcers (DFU). A multicentre, randomised, controlled, clinical trial was conducted at 11 centres in the United States. Individuals with a confirmed diagnosis of Type 1 or Type 2 diabetes presenting with a 1 to 15 cm² ulcer located below the ankle that had been persisting for at least 30 days were eligible for the 14‐day study run‐in phase. After 14 days of weekly debridement, moist wound therapy, and off‐loading, those with ≤30% wound area reduction post‐debridement (n = 155) were randomised in a 2:1 ratio to receive a weekly application of EpiCord (n = 101) or standardised therapy with alginate wound dressing, non‐adherent silicone dressing, absorbent non‐adhesive hydropolymer secondary dressing, and gauze bandage roll (n = 54). All wounds continued to have appropriate off‐loading during the treatment phase of the study. Study visits were conducted for 12 weeks. At each weekly visit, the DFU was cleaned and debrided as necessary, with the wound photographed pre‐ and post‐debridement and measured before the application of treatment group‐specific dressings. A follow‐up visit was performed at week 16. The primary study end point was the percentage of complete closure of the study ulcer within 12 weeks, as assessed by Silhouette camera. Data for randomised subjects meeting study inclusion criteria were included in an intent‐to‐treat (ITT) analysis. Additional analysis was conducted on a group of subjects (n = 134) who completed the study per protocol (PP) (EpiCord, n = 86, alginate, n = 48) and for those subjects receiving adequate debridement (EpiCord, n = 67, alginate, n = 40). ITT analysis showed that DFUs treated with EpiCord were more likely to heal within 12 weeks than those receiving alginate dressings, 71 of 101 (70%) vs 26 of 54 (48%) for EpiCord and alginate dressings, respectively, P = 0.0089. Healing rates at 12 weeks for subjects treated PP were 70 of 86 (81%) for EpiCord‐treated and 26 of 48 (54%) for alginate‐treated DFUs, P = 0.0013. For those DFUs that received adequate debridement (n = 107, ITT population), 64 of 67 (96%) of the EpiCord‐treated ulcers healed completely within 12 weeks, compared with 26 of 40 (65%) of adequately debrided alginate‐treated ulcers, P < 0.0001. Seventy‐five subjects experienced at least one adverse event, with a total of 160 adverse events recorded. There were no adverse events related to either EpiCord or alginate dressings. These results demonstrate the safety and efficacy of EpiCord as a treatment for non‐healing DFUs.

Cryopreservation and its clinical applications

Cryopreservation is a process that preserves organelles, cells, tissues, or any other biological constructs by cooling the samples to very low temperatures. The responses of living cells to ice formation are of theoretical interest and practical relevance. Stem cells and other viable tissues, which have great potential for use in basic research as well as for many medical applications, cannot be stored with simple cooling or freezing for a long time because ice crystal formation, osmotic shock, and membrane damage during freezing and thawing will cause cell death. The successful cryopreservation of cells and tissues has been gradually increasing in recent years, with the use of cryoprotective agents and temperature control equipment. Continuous understanding of the physical and chemical properties that occur in the freezing and thawing cycle will be necessary for the successful cryopreservation of cells or tissues and their clinical applications. In this review, we briefly address representative cryopreservation processes, such as slow freezing and vitrification, and the available cryoprotective agents. In addition, some adverse effects of cryopreservation are mentioned.

Defined three-dimensional culture conditions mediate efficient induction of definitive endoderm lineage from human umbilical cord Wharton's jelly mesenchymal stem cells

Background

Wharton’s jelly-derived mesenchymal stem cells (WJ-MSCs) are gaining increasing interest as an alternative source of stem cells for regenerative medicine applications. Definitive endoderm (DE) specification is a prerequisite for the development of vital organs such as liver and pancreas. Hence, efficient induction of the DE lineage from stem cells is crucial for subsequent generation of clinically relevant cell types. Here we present a defined 3D differentiation protocol of WJ-MSCs into DE cells.

Methods

WJ-MSCs were cultured in suspension to generate spheroids, about 1500 cells each, for 7 days. The serum-free differentiation media contained specific growth factors, cytokines, and small molecules that specifically regulate signaling pathways including sonic hedgehog, bone morphogenetic protein, Activin/Wnt, and Notch.

Results

We obtained more than 85 % DE cells as shown with FACS analysis using antibodies directed against the DE marker CXCR4. In addition, biochemical and molecular analysis of bona-fide DE markers revealed a time-course induction of Sox17, CXCR4, and FoxA2. Focused PCR-based array also indicated a specific induction into the DE lineage.

Conclusions

In this study, we report an efficient serum-free protocol to differentiate WJ-MSCs into DE cells utilizing 3D spheroid formation. Our approach might aid in the development of new protocols to obtain DE-derivative lineages including liver-like and pancreatic insulin-producing cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-016-0426-9) contains supplementary material, which is available to authorized users.