Differentiation of human adipose stromal cells into hepatic lineage in vitro and in vivo

Stem Cell-Based Strategies: The Future Direction of Bioartificial Liver Development

Acute liver failure (ALF) results from severe liver damage or end-stage liver disease. It is extremely fatal and causes serious health and economic burdens worldwide. Once ALF occurs, liver transplantation (LT) is the only definitive and recommended treatment; however, LT is limited by the scarcity of liver grafts. Consequently, the clinical use of bioartificial liver (BAL) has been proposed as a treatment strategy for ALF. Human primary hepatocytes are an ideal cell source for these methods. However, their high demand and superior viability prevent their widespread use. Hence, finding alternatives that meet the seed cell quality and quantity requirements is imperative. Stem cells with self-renewing, immunogenic, and differentiative capacities are potential cell sources. MSCs and its secretomes encompass a spectrum of beneficial properties, such as anti-inflammatory, immunomodulatory, anti-ROS (reactive oxygen species), anti-apoptotic, pro-metabolomic, anti-fibrogenesis, and pro-regenerative attributes. This review focused on the recent status and future directions of stem cell-based strategies in BAL for ALF. Additionally, we discussed the opportunities and challenges associated with promoting such strategies for clinical applications.

Differentiation of Adipose Tissue Mesenchymal Stem Cells into Endothelial Cells Depends on Fat Depot Conditions: Regulation by miRNA

The development of obesity is associated with substantial modulation of adipose tissue (AT) structure. The plasticity of the AT is reflected by its remarkable ability to expand or reduce in size throughout the adult lifespan, which is linked to the development of its vasculature. This increase in AT vasculature could be mediated by the differentiation of adipose tissue-derived stem cells (ASCs) into endothelial cells (ECs) and form new microvasculature. We have already shown that microRNA (miRNA)-145 regulates the differentiation of ASCs into EC-like (ECL) cells. Here, we investigated whether ASCs-differentiation into ECs is governed by a miRNAs signature that depends on fat depot location and /or the metabolic condition produced by obesity. Human ASCs, which were obtained from white AT by surgical procedures from lean and obese patients, were induced to differentiate into ECL cells. We have identified that miRNA-29b-3p in both subcutaneous (s)ASCs and visceral ASCs and miRNA-424-5p and miRNA-378a-3p in subcutaneous (s)ASCs are involved in differentiation into EC-like cells. These miRNAs modulate their pro-angiogenic effects on ASCs by targeting FGFR1, NRP2, MAPK1, and TGF-β2, and the MAPK signaling pathway. We show for the first time that miRNA-29b-3p upregulation contributes to ASCs' differentiation into ECL cells by directly targeting TGFB2 in both sASCs and visceral ASCs. Moreover, our results reveal that, independent of sASCs' origin (obese/lean), the upregulation of miRNA-378a-3p and the downregulation of miRNA-424-5p inhibit MAPK1 and overexpress FGFR1 and NRP2, respectively. In summary, both the adipose depot location and obesity affect the differentiation of resident ASCs through the expression of specific miRNAs.

Molecular mechanism underlying miR-204-5p regulation of adipose-derived stem cells differentiation into cells from three germ layers

The limited differentiation ability of adipose-derived stem cells (ADSCs) limits their application in stem cell therapy and regenerative medicine. Here, we explore the molecular mechanism by which miR-204-5p regulates ADSCs differentiation into cells derived from the three germ layers (i.e., adipocytes, neurocytes, and hepatocytes). Although miR-204-5p overexpression inhibited ADSCs differentiation into adipocytes, neurocyte and hepatocyte differentiation were promoted. Mechanistically, miR-204-5p inhibited the expression of PPARG by regulating the AMPK signaling pathway, thereby inhibiting ADSCs differentiation into adipocytes. Further, miR-204-5p regulated JAG1/NOTCH3 axis for the inhibition of differentiation into adipocytes and promotion of differentiation into neurocytes. miR-204-5p might also promote ADSCs differentiation into hepatocytes by upregulating E2F8. The findings of this study provide novel insights into the regulatory mechanisms underlying early embryonic development and will help to facilitate the application of ADSCs in stem cell therapy and regenerative medicine.

Advances in the Treatment of Kidney Disorders using Mesenchymal Stem Cells

Renal disease is a medical condition that poses a potential threat to the life of an individual and is related to substantial morbidity and mortality rates in clinical environments. The aetiology of this condition is influenced by multiple factors, and its incidence tends to increase with progressive aging. Although supportive therapy and kidney transplantation have potential advantages, they also have limitations in terms of mitigating the progression of KD. Despite significant advancements in the domain of supportive therapy, mortality rates in patients continue to increase. Due to their ability to self-renew and multidirectionally differentiate, stem cell therapy has been shown to have tremendous potential in the repair of the diseased kidney. MSCs (Mesenchymal stem cells) are a cell population that is extensively distributed and can be located in various niches throughout an individual's lifespan. The cells in question are characterised by their potential for indefinite replication and their aptitude for undergoing differentiation into fully developed cells of mesodermal origin under laboratory conditions. It is essential to emphasize that MSCs have demonstrated a favorable safety profile and efficacy as a therapeutic intervention for renal diseases in both preclinical as well as clinical investigations. MSCs have been found to slow the advancement of kidney disease, and this impact is thought to be due to their control over a number of physiological processes, including immunological response, tubular epithelial- mesenchymal transition, oxidative stress, renal tubular cell death, and angiogenesis. In addition, MSCs demonstrate recognised effectiveness in managing both acute and chronic kidney diseases via paracrine pathways. The proposal to utilise a therapy that is based on stem-cells as an effective treatment has been put forward in search of discovering novel therapies to promote renal regeneration. Preclinical researchers have demonstrated that various types of stem cells can provide advantages in acute and chronic kidney disease. Moreover, preliminary results from clinical trials have suggested that these interventions are both safe and well-tolerated. This manuscript provides a brief overview of the potential renoprotective effects of stem cell-based treatments in acute as well as chronic renal dysfunction. Furthermore, the mechanisms that govern the process of kidney regeneration induced by stem cells are investigated. This article will examine the therapeutic approaches that make use of stem cells for the treatment of kidney disorders. The analysis will cover various cellular sources that have been utilised, potential mechanisms involved, and the outcomes that have been achieved so far.

Liver Disease and Cell Therapy: Advances Made and Remaining Challenges

The limited availability of organs for liver transplantation, the ultimate curative treatment for end stage liver disease, has resulted in a growing and unmet need for alternative therapies. Mesenchymal stromal cells (MSCs) with their broad ranging anti-inflammatory and immunomodulatory properties have therefore emerged as a promising therapeutic agent in treating inflammatory liver disease. Significant strides have been made in exploring their biological activity. Clinical application of MSC has shifted the paradigm from using their regenerative potential to one which harnesses their immunomodulatory properties. Reassuringly, MSCs have been extensively investigated for over 30 years with encouraging efficacy and safety data from translational and early phase clinical studies, but questions remain about their utility. Therefore, in this review, we examine the translational and clinical studies using MSCs in various liver diseases and their impact on dampening immune-mediated liver damage. Our key observations include progress made thus far with use of MSCs for clinical use, inconsistency in the literature to allow meaningful comparison between different studies and need for standardized protocols for MSC manufacture and administration. In addition, the emerging role of MSC-derived extracellular vesicles as an alternative to MSC has been reviewed. We have also highlighted some of the remaining clinical challenges that should be addressed before MSC can progress to be considered as therapy for patients with liver disease.

Synthesis and In Vitro α-Amylase and α-Glucosidase Dual Inhibitory Activities of 1,2,4-Triazole-Bearing bis-Hydrazone Derivatives and Their Molecular Docking Study

There is an increasing prevalence of diabetes mellitus throughout the world, and new compounds are necessary to combat this. The currently available antidiabetic therapies are long-term complicated and side effect-prone, and this has led to a demand for more affordable and more effective methods of tackling diabetes. Research is focused on finding alternative medicinal remedies with significant antidiabetic efficacy as well as low adverse effects. In this research work, we have focused our efforts to synthesize a series of 1,2,4-triazole-based bis-hydrazones and evaluated their antidiabetic properties. In addition, the precise structures of the synthesized derivatives were confirmed with the help of various spectroscopic techniques including ¹H-NMR, ¹³C-NMR, and HREI-MS. To find the antidiabetic potentials of the synthesized compounds, in vitro α-glucosidase and α-amylase inhibitory activities were characterized using acarbose as the reference standard. From structure-activity (SAR) analysis, it was confirmed that any variation found in inhibitory activities of both α-amylase and α-glucosidase enzymes was due to the different substitution patterns of the substituent(s) at variable positions of both aryl rings A and B. The results of the antidiabetic assay were very encouraging and showed moderate to good inhibitory potentials with IC₅₀ values ranging from 0.70 ± 0.05 to 35.70 ± 0.80 μM (α-amylase) and 1.10 ± 0.05 to 30.40 ± 0.70 μM (α-glucosidase). The obtained results were compared to those of the standard acarbose drug (IC₅₀ = 10.30 ± 0.20 μM for α-amylase and IC₅₀ = 9.80 ± 0.20 μM for α-glucosidase). Specifically, compounds 17, 15, and 16 were found to be significantly active with IC₅₀ values of 0.70 ± 0.05, 1.80 ± 0.10, and 2.10 ± 0.10 μM against α-amylase and 1.10 ± 0.05, 1.50 ± 0.05, and 1.70 ± 0.10 μM against α-glucosidase, respectively. These findings reveal that triazole-containing bis-hydrazones act as α-amylase and α-glucosidase inhibitors, which help develop novel therapeutics for treating type-II diabetes mellitus and can act as lead molecules in drug discovery as potential antidiabetic agents.

In Vitro Generated Equine Hepatic-Like Progenitor Cells as a Novel Potent Cell Pool for Equine Metabolic Syndrome (EMS) Treatment

Equine metabolic syndrome (EMS) is recognized as one of the leading cause of health threatening in veterinary medicine worldwide. Recently, PTP1B inhibition has been proposed as an interesting strategy for liver insulin resistance reversion in both equines and humans, however as being a multifactorial disease, proper management of EMS horses further necessities additional interventional approaches aiming at repairing and restoring liver functions. In this study, we hypothesized that in vitro induction of Eq_ASCs hepatogenic differentiation will generate a specialized liver progenitor-like cell population exhibiting similar phenotypic characteristics and regenerative potential as native hepatic progenitor cells. Our obtained data demonstrated that Eq_ASCs-derived liver progenitor cells (Eq_HPCs) displayed typical flattened polygonal morphology with packed fragmented mitochondrial net, lowered mesenchymal CD105 and CD90 surface markers expression, and significant high expression levels of specific hepatic lineage genes including PECAM-1, ALB, AFP and HNF4A. therewith, generated Eq_HPCs exhibited potentiated stemness and pluripotency markers expression (NANOG, SOX-2 and OCT-4). Hence, in vitro generation of hepatic progenitor-like cells retaining high differentiation capacity represents a promising new approach for the establishment of cell-based targeted therapies for the restoration of proper liver functions in EMS affected horses.

Development and characterization of three cell culture systems to investigate the relationship between primary bone marrow adipocytes and myeloma cells

The unique properties of the bone marrow (BM) allow for migration and proliferation of multiple myeloma (MM) cells while also providing the perfect environment for development of quiescent, drug-resistant MM cell clones. BM adipocytes (BMAds) have recently been identified as important contributors to systemic adipokine levels, bone strength, hematopoiesis, and progression of metastatic and primary BM cancers, such as MM. Recent studies in myeloma suggest that BMAds can be reprogrammed by tumor cells to contribute to myeloma-induced bone disease, and, reciprocally, BMAds support MM cells in vitro. Importantly, most data investigating BMAds have been generated using adipocytes generated by differentiating BM-derived mesenchymal stromal cells (BMSCs) into adipocytes in vitro using adipogenic media, due to the extreme technical challenges associated with isolating and culturing primary adipocytes. However, if studies could be performed with primary adipocytes, then they likely will recapitulate in vivo biology better than BMSC-derived adipocytes, as the differentiation process is artificial and differs from in vivo differentiation, and progenitor cell(s) of the primary BMAd (pBMAds) may not be the same as the BMSCs precursors used for adipogenic differentiation in vitro. Therefore, we developed and refined three methods for culturing pBMAds: two-dimensional (2D) coverslips, 2D transwells, and three-dimensional (3D) silk scaffolds, all of which can be cultured alone or with MM cells to investigate bidirectional tumor-host signaling. To develop an in vitro model with a tissue-like structure to mimic the BM microenvironment, we developed the first 3D, tissue engineered model utilizing pBMAds derived from human BM. We found that pBMAds, which are extremely fragile, can be isolated and stably cultured in 2D for 10 days and in 3D for up to 4 week in vitro. To investigate the relationship between pBMAds and myeloma, MM cells can be added to investigate physical relationships through confocal imaging and soluble signaling molecules via mass spectrometry. In summary, we developed three in vitro cell culture systems to study pBMAds and myeloma cells, which could be adapted to investigate many diseases and biological processes involving the BM, including other bone-homing tumor types.

Molecular iodine-promoted oxidative cyclization for the synthesis of 1,3,4-thiadiazole-fused- [1,2,4]-thiadiazole incorporating 1,4-benzodioxine moiety as potent inhibitors of α-amylase and α-glucosidase: In vitro and in silico study

Twenty-five analogs were synthesized based on 1,3,4-thiadiazole-fused-[1,2,4]-thiadiazole incorporating 1,4-benzodioxine moiety (1-25) and then tested for the antidiabetic profile. The entire afforded derivatives showed varied inhibition profiles ranging between 0.70 ± 0.01 and 30.80 ± 0.80 μM (against α-amylase) in comparison to standard acarbose (12.80 ± 0.10 μM). Similarly, synthetics analogs also displayed a varied range of α-glucosidase activity ranging from 0.80 ± 0.01 μM to IC50 = 29.70 ± 0.40 μM (against α-glucosidase) as compared to standard acarbose (IC50 = 12.90 ± 0.10 μM). Among synthesized analogs, compound 22 showed excellent potency due to the presence of di-hydroxy substitutions at the 2,3-position of the aryl ring. For all analogs, the structure-activity relationship was carried out based on the pattern of substitutions around the aryl ring, and further, the potent analogs were subjected to a molecular docking study to analyze how active residues of targeted enzymes interact with active parts of newly prepared analogs. The result obtained shows that these compounds furnish several key interactions with enzyme active sites and, hence, enhanced their enzymatic activities.

Organ-Specific Differentiation of Human Adipose-Derived Stem Cells in Various Organs of Xenotransplanted Rats: A Pilot Study

Adipose-derived stem cells (ADSCs) are potential therapeutics considering their self-renewal capacity and ability to differentiate into all somatic cell types in vitro. The ideal ADSC-based therapy is a direct injection into the relevant organs. The objective of this study was to investigate the viability and safety of intra-organ human ADSC (h-ADSC) xenotransplants in vivo. Subcutaneous adipose tissue from the abdominal area of 10 patients was sampled. h-ADSCs were isolated from adipose tissue samples and identified using immunofluorescence antibodies. Multi-differentiation potential assays for adipocytes, osteocytes, and chondrocytes were performed. Cultured h-ADSCs at passage 4 were transplanted into multiple organs of 17 rats, including the skin, subcutaneous layer, liver, kidney, pancreas, and spleen. The h-ADSC-injected organs excised after 100 days were examined, and the survival of h-ADSCs was measured by quantitative real-time polymerase chain reaction (qRT-PCR) using specific human and rat target genes. h-ADSCs confirmed by stem cell phenotyping were induced to differentiate into adipogenic, osteogenic, and chondrogenic lineages in vitro. All rats were healthy and exhibited no side effects during the study; the transplanted h-ADSCs did not cause inflammation and were indiscernible from the native organ cells. The presence of transplanted h-ADSCs was confirmed using qRT-PCR. However, the engrafted survival rates varied as follows: subcutaneous fat (70.6%), followed by the liver (52.9%), pancreas (50.0%), kidney (29.4%), skin (29.4%), and spleen (12.5%). h-ADSCs were successfully transplanted into a rat model, with different survival rates depending on the organ.

Clinical Application of Induced Hepatocyte-like Cells Produced from Mesenchymal Stromal Cells: A Literature Review

Liver disease is a leading cause of mortality worldwide, resulting in 1.3 million deaths annually. The vast majority of liver disease is caused by metabolic disease (i.e., NASH) and alcohol-induced hepatitis, and to a lesser extent by acute and chronic viral infection. Furthermore, multiple insults to the liver is becoming common due to the prevalence of metabolic and alcohol-related liver diseases. Despite this rising prevalence of liver disease, there are few treatment options: there are treatments for viral hepatitis C and there is vaccination for hepatitis B. Aside from the management of metabolic syndrome, no direct liver therapy has shown clinical efficacy for metabolic liver disease, there is very little for acute alcohol-induced liver disease, and liver transplantation remains the only effective treatment for late-stage liver disease. Traditional pharmacologic interventions have failed to appreciably impact the pathophysiology of alcohol-related liver disease or end-stage liver disease. The difficulties associated with developing liver-specific therapies result from three factors that are common to late-stage liver disease arising from any cause: hepatocyte injury, inflammation, and aberrant tissue healing. Hepatocyte injury results in tissue damage with inflammation, which sensitizes the liver to additional hepatocyte injury and stimulates hepatic stellate cells and aberrant tissue healing responses. In the setting of chronic liver insults, there is progressive scarring, the loss of hepatocyte function, and hemodynamic dysregulation. Regenerative strategies using hepatocyte-like cells that are manufactured from mesenchymal stromal cells may be able to correct this pathophysiology through multiple mechanisms of action. Preclinical studies support their effectiveness and recent clinical studies suggest that cell replacement therapy can be safe and effective in patients with liver disease for whom there is no other option.

Efficient generation of functional pancreatic β cells from dental-derived stem cells via laminin-induced differentiation

Background

This study was designed to generate functional insulin-producing cells (IPCs) from dental-derived mesenchymal stem cells (MSCs) and further explore their therapeutic potential against diabetes mellitus in vivo. MSCs were isolated from human dental pulp and periodontal ligament and were induced to differentiate into insulin-producing cells (IPCs) using laminin-based differentiation protocol for 14 days. Confirmation of IPCs was performed through real-time PCR analysis and insulin release assay. Then, the generated IPCs were labeled with PKH26 dye prior to transplantation in experimental animals. Twenty-eight days later, blood glucose, serum insulin (INS), c-peptide (CP), and visfatin (VF) levels and pancreatic glucagon (GC) level were estimated. Pancreatic forkhead box protein A2 (Foxa2) and SRY-box transcription factor 17 (Sox17), insulin-like growth factor I (IGF-1), and fibroblast growth factor10 (FGF 10) gene expression levels were analyzed.

Results

Dental stem cells were successfully differentiated into IPCs that demonstrated increased expression of pancreatic endocrine genes. IPCs released insulin after being subjected to high levels of glucose. In vivo findings uncovered that the implanted IPCs triggered significant decrease in blood glucose, serum VF, and pancreatic GC levels with significant increase in serum INS and CP levels. Furthermore, the implanted IPCs provoked significant upregulation in the expression level of pancreatic genes. Histopathological description of the pancreas tissues revealed that transplantation of IPCs ameliorated the destabilization of pancreas tissue architecture.

Conclusion

This study demonstrates the significant role of the implantation of IPCs generated from dental-derived stem cells in treatment of diabetes mellitus.

Mesenchymal Stromal Cells in Osteoarthritis: Evidence for Structural Benefit and Cartilage Repair

Osteoarthritis (OA) presents a major clinical challenge to rheumatologists and orthopedists due to the lack of available drugs reducing structural degradation. Mesenchymal stromal cells (MSCs) may represent new therapeutic approaches in cartilage regeneration. In this review, we highlight the latest knowledge on the biological properties of MSC, such as their chondrogenic and immunomodulatory potential, and we give a brief overview of the effects of MSCs in preclinical and clinical studies of OA treatment and also compare different MSC sources, with the adipose tissue-derived MSCs being promising. Then, we focus on their structural benefit in treating OA and summarize the current evidence for the assessment of cartilage in OA according to magnetic resonance imaging (MRI) and second-look arthroscopy after MSC therapy. Finally, this review provides a brief perspective on enhancing the activity of MSCs.

Human Adipose-Derived Stem Cells Combined with Nano-Hydrogel Promote Functional Recovery after Spinal Cord Injury in Rats

Simple Summary

Nerve regeneration and functional recovery after spinal cord injury (SCI) are worldwide problems. Scientists have achieved encouraging results in the repair of spinal cord injuries using natural or synthetic materials. In this paper, we report that nano-hydrogel combined with human adipose-derived stem cells regulate the inflammatory microenvironment, protect neurons and axons, and promote motor function recovery. In addition, three proteins related to neuronal and axonal growth were screened by Liquid chromatography-mass spectrometry. These results provide evidence for clinical treatment of spinal cord injury.

Abstract

The treatment of spinal cord injury aims to reconstruct the fiber connection and restore the interrupted neural pathways. Adipose mesenchymal stem cells (ADSCs) can promote the recovery of motor functions in spinal cord injury. However, poor survival of ADSCs and leakage outside of the injury site after local transplantation reduce the number of cells, which seriously attenuates the cumulative effect. We performed heterotopic transplantation on rats with severe spinal cord injury using human ADSCs loaded within self-assembly hydrogel RADA16-RGD (R: arginine; A: alanine; D: aspartic acid; G: glycine). Our results indicate that the combined transplantation of human ADSCs with RADA16-RGD improved the survival of ADSCs at the injured site. The inflammatory reaction was inhibited, with improved survival of the neurons and increased residual area of nerve fibers and myelin protein. The functional behaviors were promoted, as determined by the Basso, Beattie, and Bresnahan (BBB) locomotor rating scale score and electrophysiological measurements. ADSCs can promote the repair of spinal cord injury. This study provides new ideas for the treatment of spinal cord injury.

Vapor construction and modification of stem cell-laden multicomponent scaffolds for regenerative therapeutics

Tissue engineering based on the combined use of isolated cells, scaffolds, and growth factors is widely used; however, the manufacture of cell-preloaded scaffolds faces challenges. Herein, we fabricated a multicomponent scaffold with multiple component accommodations, including bioactive molecules (BMs), such as fibroblast growth factor-2 (FGF-2) and l-ascorbic acid 2-phosphate (A2-P), and living cells of human adipose-derived stem cells (hASCs), within one scaffold construct. We report an innovative fabrication process based on vapor-phased construction using iced templates for vapor sublimation. Simultaneously, the vaporized water molecules were replaced by vapor deposition of poly-p-xylylene (PPX, USP Class VI, highly compatible polymer, FDA-approved records), forming a three-dimensional and porous scaffold matrix. More importantly, a multicomponent modification was achieved based on using nonvolatile solutes, including bioactive molecules of FGF-2 and A2-P, and living cells of hASCs, to prepare iced templates for sublimation. Additionally, the fabrication and construction resulted in a multicomponent scaffold product comprising the devised molecules, cells, and vapor-polymerized poly-p-xylylene as the scaffold matrix. The clean and dry fabrication process did not require catalysts, initiators or plasticizers, and potentially harmful solvents, and the scaffold products were produced in simple steps within hours of the processing time. Cell viability analysis showed a high survival rate (approximately 86.4%) for the accommodated hASCs in the fabricated scaffold product, and a surprising multilineage differentiation potential of hASCs was highly upregulated because of synergistic guidance by the same accommodated FGF-2 and A2-P components. Proliferation and self-renewal activities were also demonstrated with enhancement of the multicomponent scaffold product. Finally, in vivo calvarial defect studies further revealed that the constructed scaffolds provided blood vessels to grow into the bone defect areas with enhancement, and the induced conduction of osteoblast growth also promoted bone healing toward osseointegration. The reported scaffold construction technology represents a prospective tissue engineering scaffold product to enable accommodable and customizable versatility to control the distribution and composition of loading delicate BMs and living hASCs in one scaffold construct and demonstrates unlimited applications in tissue engineering repair and regenerative medicine applications.

The role of mesenchymal stem cells in liver injury

Recently, mesenchymal stem cell (MSC) therapy has been suggested as an effective alternate approach for the treatment of hepatic diseases. MSCs have potential therapeutic value, because these have high self-renewal ability, are capable of multipotent differentiation, and have low immunogenicity. Furthermore, MSCs have the potential to differentiate into hepatocytes, and the therapeutic value exists in their immune-modulatory properties and secretion of trophic factors, such as growth factors and cytokines. Moreover, MSCs can suppress inflammatory responses, reduce hepatocyte apoptosis, increase hepatocyte regeneration, regress liver fibrosis, and enhance liver functionality. This article is protected by copyright. All rights reserved.

Chemically Defined Conditions Mediate an Efficient Induction of Dental Pulp Pluripotent-Like Stem Cells into Hepatocyte-Like Cells

Liver diseases are major causes of morbidity and mortality. Dental pulp pluripotent-like stem cells (DPPSCs) are of a considerable promise in tissue engineering and regenerative medicine as a new source of tissue-specific cells; therefore, this study is aimed at demonstrating their ability to generate functional hepatocyte-like cells in vitro. Cells were differentiated on a collagen scaffold in serum-free media supplemented with growth factors and cytokines to recapitulate liver development. At day 5, the differentiated DPPSC cells expressed the endodermal markers FOXA1 and FOXA2. Then, the cells were derived into the hepatic lineage generating hepatocyte-like cells. In addition to the associated morphological changes, the cells expressed the hepatic genes HNF6 and AFP. The terminally differentiated hepatocyte-like cells expressed the liver functional proteins albumin and CYP3A4. In this study, we report an efficient serum-free protocol to differentiate DPPSCs into functional hepatocyte-like cells. Our approach promotes the use of DPPSCs as a new source of adult stem cells for prospective use in liver regenerative medicine.

Human Adipose-Derived Mesenchymal Stromal Cells Exhibit High HLA-DR Levels and Altered Cellular Characteristics under a Xeno-free and Serum-free Condition

Background

We have observed an increased expression of negative markers in some clinical-grade, xeno- and serum-free cultured adipose-derived mesenchymal stem/stromal cell (ADMSC) samples. It gave rise to concern that xeno- and serum-free conditions might have unexpected effects on human ADMSCs. This study aims to test this hypothesis for two xeno- and serum-free media, PowerStem MSC1 media (PS) and StemMACS MSC Expansion Media (SM), that support the in vitro expansion of ADMSCs.

Methods

We investigated the expression of negative markers in 42 clinical-grade ADMSC samples expanded in PS. Next, we cultured ADMSCs from seven donors in PS and SM and examined their growth and colony-forming ability, surface marker expression, differentiation, cell cycle and senescence, as well as genetic stability of two passages representing an early and late passage for therapeutic MSCs.

Results

15 of 42 clinical-grade PS-expanded ADMSC samples showed an increased expression of negative markers ranging from 2.73% to 34.24%, which positively correlated with the age of donors. This rise of negative markers was related to an upregulation of Human Leukocyte Antigen – DR (HLA-DR). In addition, the PS-cultured cells presented decreased growth ability, lower frequencies of cells in S/G2/M phases, and increased ß-galactosidase activity in passage 7 suggesting their senescent feature compared to those grown in SM. Although MSCs of both PS and SM cultures were capable of multilineage differentiation, the PS-cultured cells demonstrated chromosomal abnormalities in passage 7 compared to the normal karyotype of their SM counterparts.

Conclusions

These findings suggest that the SM media is more suitable for the expansion of therapeutic ADMSCs than PS. The study also hints a change of ADMSC features at more advanced passages and with increased donor’s age. Thus, it emphasizes the necessity to cover these aspects in the quality control of therapeutic MSC products.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s12015-021-10242-7.

Differentiation of Adipose-Derived Stem Cells into Vascular Smooth Muscle Cells for Tissue Engineering Applications

Synthetic grafts have been developed for vascular bypass surgery, however, the risks of thrombosis and neointimal hyperplasia still limit their use. Tissue engineering with the use of adipose-derived stem cells (ASCs) has shown promise in addressing these limitations. Here we further characterized and optimized the ASC differentiation into smooth muscle cells (VSMCs) induced by TGF-β and BMP-4. TGF-β and BMP-4 induced a time-dependent expression of SMC markers in ASC. Shortening the differentiation period from 7 to 4 days did not impair the functional property of contraction in these cells. Stability of the process was demonstrated by switching cells to regular growth media for up to 14 days. The role of IGFBP7, a downstream effector of TGF-β, was also examined. Finally, topographic and surface patterning of a substrate is recognized as a powerful tool for regulating cell differentiation. Here we provide evidence that a non-woven PET structure does not affect the differentiation of ASC. Taken together, our results indicate that VSMCs differentiated from ASCs are a suitable candidate to populate a PET-based vascular scaffolds. By employing an autologous source of cells we provide a novel alternative to address major issues that reduces long-term patency of currently vascular grafts.

Adipose Tissue-Derived Stem Cell Yield Depends on Isolation Protocol and Cell Counting Method

In plastic surgery, lipofilling is a frequent procedure. Unsatisfactory vascularization and impaired cell vitality can lead to unpredictable take rates in the fat graft. The proliferation and neovascularization inducing properties of adipose tissue-derived stem cells may contribute to solve this problem. Therefore, the enrichment of fat grafts with stem cells is studied intensively. However, it is difficult to compare these studies because many factors—often not precisely described—are influencing the results. Our study summarizes some factors which influence the cell yield like harvesting, isolation procedure and quantification. Stem cells were isolated after liposuction. Quantification was done using a cell chamber, colony counting, or flow cytometry with changes to one parameter, only, for each comparison. Quantification of cells isolated after liposuction at the same harvesting site from the same patient can vary greatly depending on the details of the isolation protocol and the method of quantification. Cell yield can be influenced strongly by many factors. Therefore, a comparison of different studies should be handled with care.

Selective Proliferation of Highly Functional Adipose-Derived Stem Cells in Microgravity Culture with Stirred Microspheres

Therapeutic effects of adult stem-cell transplantations are limited by poor cell-retention in target organs, and a reduced potential for optimal cell differentiation compared to embryonic stem cells. However, contemporary studies have indicated heterogeneity within adult stem-cell pools, and a novel culturing technique may address these limitations by selecting those for cell proliferation which are highly functional. Here, we report the preservation of stemness in human adipose-derived stem cells (hASCs) by using microgravity conditions combined with microspheres in a stirred suspension. The cells were bound to microspheres (100-300 μm) and cultured using a wave-stirring shaker. One-week cultures using polystyrene and collagen microspheres increased the proportions of SSEA-3(+) hASCs 4.4- and 4.3-fold (2.7- and 2.9-fold increases in their numbers), respectively, compared to normal culture conditions. These cultured hASCs expressed higher levels of pluripotent markers (OCT4, SOX2, NANOG, MYC, and KLF), and had improved abilities for proliferation, colony formation, network formation, and multiple-mesenchymal differentiation. We believe that this novel culturing method may further enhance regenerative therapies using hASCs.

Adipose derived stem cells to construct parathyroid organoid for hypoparathyroidism

Hypoparathyroidism is one of the most common postoperative complications of thyroid surgery, and organoid transplantation is a frontier field expected to treat hypoparathyroidism. Organoids are three-dimensional cell aggregates derived from embryonic stem cells, pluripotent stem cells, or tissue precursor cells, possessing similar structures and functions to organs. Thus they can replace diseased organs to play a role. Adipose-derived stem cells (ASCs) are a population of postnatal stem cells residing in the fat tissue, capable of differentiating into parathyroid-like cells with parathyroid hormone secretion function. Additionally, we have prepared cartilaginous organoids by intelligent porous hydrogel and differentiated ASCs via "bottom-up" strategy in vitro. Therefore, we speculate that parathyroid organoids can be achieved by the biomaterial-assisted assembly of differentiated adipose stem cells and it is a promising treatment for hypoparathyroidism.

GSK3 inhibitor ameliorates steatosis through the modulation of mitochondrial dysfunction in hepatocytes of obese patients

Obesity is an important risk factor and a potential treatment target for hepatic steatosis. The maladaptation of hepatic mitochondrial flexibility plays a key role in the hepatic steatosis. Herein, we found that hepatocyte-like cells derived from human adipose stem cell of obese patients exhibited the characteristics of hepatic steatosis and accompanied with lower expression of the subunits of mitochondrial complex I and lower oxidative phosphorylation levels. The GSK3 inhibitor CHIR-99021 promoted the expression of NDUFB8, NDUFB9, the subunits of mitochondrial complex I, the basal oxygen consumption rate, and the fatty acid oxidation of the hepatocytes of obese patients by upregulating the expression of the transcription factor PGC-1α, TFAM, and NRF1 involved in mitochondrial biogenesis. Moreover, CHIR-99021 decreased the lipid droplets size and the triglyceride levels in hepatocytes of obese patients. The results demonstrate that GSK3 inhibition ameliorates hepatic steatosis by elevating the mitochondrial function in hepatocytes of obese patients.

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Obese patients’ adipose-stem-cell-derived hepatocytes reveal hepatic steatosis

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Hepatic steatosis is accompanied the mitochondrial dysfunction

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The mitochondrial dysfunction is governed by the low expression PGC-1α, TFAM, and NRF1

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GSK3 inhibitor ameliorates hepatic steatosis via mitochondrial dysfunction modulation

Hepatic cell-sheet fabrication of differentiated mesenchymal stem cells using decellularized extracellular matrix and thermoresponsive polymer

PURPOSE

Liver tissue engineering via cell sheet technology would open new doors for treatment of patients with liver failure. Decellularized tissues could provide sufficient extracellular matrix (ECM) to support development of hepatocytes in in vivo niches. Besides, with the potential of temperature responsive polymer (pNIPAAm) as an intelligent surface for controlling the attachment/detachment of cell, we set out to generate three in vitro microenvironments models including I: pNIPAAm hydrogel (pN hydrogel), II: decellularized ECM incorporated into pNIPAAm hydrogel (dECM + pN hydrogel) and III: decellularized ECM scaffold (dECM scaffold) to investigate the structural and function cues of hepatocyte-like cells after differentiation of adipose tissue-derived mesenchymal stem cells (AT-MSCs) on the surface of these models.

METHOD

dECM scaffold was obtained after decellularization of rat liver, and its efficiency was analyzed. pN hydrogel and dECM + pN hydrogel (1:3 and 2:3 ratios) of were fabricated, and scaffold architecture was characterized. Each well of culturing plates was coated separately with these three constructs and AT-MSCs were instructed to differentiate into hepatocyte-like cells (HLCs). After recellularization, patterns of differentiation, and expression of hepatogenic markers were investigated via biochemical assays and qRT-PCR at different time points.

RESULTS

Multipotency of AT-MSCs, after their ability for osteogenesis and adipogenesis was documented. Production of dense and intact cell sheets was reported in dECM + pN hydrogel, as opposed to pN hydrogel and dECM scaffold. Also, statistically significant difference of HLCs functionality in dECM + pN hydrogel was confirmed after evaluation of the expression of hepatocyte markers including, alpha-fetoprotein, cytokeratin 18, cytochrome P450-2E1 and phosphoenolpyruvate carboxykinase.

CONCLUSION

Our results proved dECM + pN hydrogel were able to preserve hepatocyte function in cell sheets owing to the high level of albumin, urea, hepatogenic markers, and glycogenesis potential of HLCs. Accordingly, dECM incorporated in pN hydrogel could remodel microenvironments to guide the AT-MSCs into conducive differentiation and proliferation to give rise to multilayer sheets of cells in their own ECM.

Fat grafts enriched with adipose-derived stem cells

Autologous fat grafts are widely used in soft-tissue augmentation and reconstruction. To reduce the unpredictability of fat grafts and to improve their long-term survival, cell-assisted lipotransfer (CAL) was introduced. In this alternative method, autologous fat is mixed and grafted with stromal vascular fraction cells or adipose-derived stem/stromal cells (ASCs). In regenerative medicine, ASCs exhibit excellent therapeutic potential and are also simple to harvest. Although the efficacy of CAL has been demonstrated in experimental and clinical research, studies on its safety in terms of oncologic risk have reported inconclusive results. In order to establish CAL as a viable stem cell therapeutic approach, it will be necessary to demonstrate its oncologic safety in basic and clinical studies. Doing so could transform the paradigm of clinical strategy and practice for the treatment of a wide variety of diseases.

Founder cells for hepatocytes during liver regeneration: from identification to application

Liver regeneration (LR) capacity in vertebrates developed through natural selection over a hundred million years of evolution. To maintain homeostasis or recover from various injuries, liver cells must regenerate; this process includes the renewal of parenchymal and nonparenchymal cells as well as the formation of liver structures. The cellular origin of newly grown tissue is one of the critical questions in this area and has been a subject of prolonged debate. The regenerative tissue may derive from either hepatocyte self-duplication or liver stem/progenitor cells (LSPCs). Recently, hepatocyte subpopulations and cholangiocytes were also described as important founder cells. The niche that triggers the proliferation of hepatocytes and the differentiation of LSPCs has been extensively studied. Meanwhile, in vitro culture systems for liver founder cells and organoids have been developed rapidly for mechanistic studies and potential therapeutic purposes. This review summarizes the cellular sources and niches that give rise to renewed hepatocytes during LR, and it also describes in vitro culture studies of those founder cells for future applications, as well as current reports for stem cell-based therapies for liver diseases.

Recovery and maintenance of NESTIN expression in umbilical cord-MSC using a novel culture medium

Mesenchymal stem cells (MSC) are a popular candidate in cellular therapy for many diseases. MSCs are well known by their feature of self-renewal and their differentiation potential. NESTIN is a cytoskeletal protein expressed in MSC that functions directly in cell proliferation and differentiation. Here, we demonstrated that adding UltraGRO, a medium supplement, could maintain and partially recover the expression of NESTIN in human umbilical cord derived MSCs (UC-MSCs). Furthermore, the UC-MSCs cultured with UltraGRO showed a better immunomodulation ability in a colitis mouse model compared with those cultured in other types of media. This indicates that the use of novel culture medium benefits the maintenance of NESTIN expression and NESTIN may be one of the vital factors that regulates the performance of MSCs.

Human Adipose Tissue Derivatives as a Potent Native Biomaterial for Tissue Regenerative Therapies

BACKGROUND

Human adipose tissue is a great source of translatable biomaterials owing to its ease of availability and simple processing. Reusing discardable adipose tissue for tissue regeneration helps in mimicking the exact native microenvironment of tissue. Over the past 10 years, extraction, processing, tuning and fabrication of adipose tissue have grabbed the attention owing to their native therapeutic and regenerative potential. The present work gives the overview of next generation biomaterials derived from human adipose tissue and their development with clinical relevance.

METHODS

Around 300 articles have been reviewed to widen the knowledge on the isolation, characterization techniques and medical applications of human adipose tissue and its derivatives from bench to bedside. The prospective applications of adipose tissue derivatives like autologous fat graft, stromal vascular fraction, stem cells, preadipocyte, adipokines and extracellular matrix, their behavioural mechanism, rational property of providing native bioenvironment, circumventing their translational abilities, recent advances in featuring them clinically have been reviewed extensively to reveal the dormant side of human adipose tissue.

RESULTS

Basic understanding about the molecular and structural aspect of human adipose tissue is necessary to employ it constructively. This review has nailed the productive usage of human adipose tissue, in a stepwise manner from exploring the methods of extracting derivatives, concerns during processing and its formulations to turning them into functional biomaterials. Their performance as functional biomaterials for skin regeneration, wound healing, soft tissue defects, stem cell and other regenerative therapies under in vitro and in vivo conditions emphasizes the translational efficiency of adipose tissue derivatives.

CONCLUSION

In the recent years, research interest has inclination towards constructive tissue engineering and regenerative therapies. Unravelling the maximum utilization of human adipose tissue derivatives paves a way for improving existing tissue regeneration and cellular based therapies and other biomedical applications.

Recent Advance in Source, Property, Differentiation, and Applications of Infrapatellar Fat Pad Adipose-Derived Stem Cells

Infrapatellar fat pad (IPFP) can be easily obtained during knee surgery, which avoids the damage to patients for obtaining IPFP. Infrapatellar fat pad adipose-derived stem cells (IPFP-ASCs) are also called infrapatellar fat pad mesenchymal stem cells (IPFP-MSCs) because the morphology of IPFP-ASCs is similar to that of bone marrow mesenchymal stem cells (BM-MSCs). IPFP-ASCs are attracting more and more attention due to their characteristics suitable to regenerative medicine such as strong proliferation and differentiation, anti-inflammation, antiaging, secreting cytokines, multipotential capacity, and 3D culture. IPFP-ASCs can repair articular cartilage and relieve the pain caused by osteoarthritis, so most of IPFP-related review articles focus on osteoarthritis. This article reviews the anatomy and function of IPFP, as well as the discovery, amplification, multipotential capacity, and application of IPFP-ASCs in order to explain why IPFP-ASC is a superior stem cell source in regenerative medicine.

Small molecules for mesenchymal stem cell fate determination

Mesenchymal stem cells (MSCs) are adult stem cells harboring self-renewal and multilineage differentiation potential that are capable of differentiating into osteoblasts, adipocytes, or chondrocytes in vitro, and regulating the bone marrow microenvironment and adipose tissue remodeling in vivo. The process of fate determination is initiated by signaling molecules that drive MSCs into a specific lineage. Impairment of MSC fate determination leads to different bone and adipose tissue-related diseases, including aging, osteoporosis, and insulin resistance. Much progress has been made in recent years in discovering small molecules and their underlying mechanisms control the cell fate of MSCs both in vitro and in vivo. In this review, we summarize recent findings in applying small molecules to the trilineage commitment of MSCs, for instance, genistein, medicarpin, and icariin for the osteogenic cell fate commitment; isorhamnetin, risedronate, and arctigenin for pro-adipogenesis; and atractylenolides and dihydroartemisinin for chondrogenic fate determination. We highlight the underlying mechanisms, including direct regulation, epigenetic modification, and post-translational modification of signaling molecules in the AMPK, MAPK, Notch, PI3K/AKT, Hedgehog signaling pathways etc. and discuss the small molecules that are currently being studied in clinical trials. The target-based manipulation of lineage-specific commitment by small molecules offers substantial insights into bone marrow microenvironment regulation, adipose tissue homeostasis, and therapeutic strategies for MSC-related diseases.

In vitro differentiation capacity of human breastmilk stem cells: A systematic review

BACKGROUND

Mesenchymal stem cells are pluripotent cells that have the ability to generate cells from a cell line or in other cell types from different tissues but from the same origin. Although those cells have more limited differentiation capacity than embryonic stem cells, they are easily obtained from somatic tissue and can be grown in large quantities. This characteristic of undifferentiated stem cells differentiating into different cell lines arouses strategies in regenerative medicine for the treatment of different diseases such as neurodegenerative diseases.

AIM

To evaluate the cell differentiation capacity of human breastmilk stem cells for the three germ layers by a systematic review.

METHODS

The searched databases were PubMed, EMBASE, OVID, and COCHRANE LIBRARY, published between 2007 and 2018 in the English language. All were in vitro studies for analysis of the "cell differentiation potential" in the literature using the keywords “human breastmilk,” “stem cells,” and keywords combined with the Boolean operator “NOT” were used to exclude those articles that had the word “CANCER” and their respective synonyms, which were previously consulted according to medical subject heading terms. PRISMA 2009 guidelines were followed in this study.

RESULTS

A total of 315 titles and abstracts of articles were examined. From these, 21 were in common with more than one database, leaving 294 articles for analysis. Of that total, five publications met the inclusion criteria. When analyzing the publications, it was demonstrated that human breastmilk stem cells have a high cellular plasticity, exhibiting the ability to generate cells of all three germ layers, endoderm, mesoderm, and ectoderm, demonstrating their stemness. Those cells expressed the genes, TRA-1-60/81, octamer-binding transcription factor 4, and NANOG, of which NANOG, a critical regulator for self-renewal and maintenance, was the most highly expressed. Those cells have the ability to differentiate in vitro into adipocytes, chondrocytes, osteocytes, oligodendrocytes, astrocytes, and neurons as well hepatocytes, β-pancreatic cells, and cardiomyocytes.

CONCLUSION

Although the literature has been scarce, the pluripotentiality of these cells represents great potential for tissue engineering and cellular therapy. Further studies for safe clinical translation are needed.

Adipose-Derived Stem Cell Transplantation Attenuates Inflammation and Promotes Liver Regeneration after Ischemia-Reperfusion and Hemihepatectomy in Swine

Aim

To study the anti-inflammatory and liver regenerative effects of adipose-derived mesenchymal stem cells (ADSCs) on a porcine model of ischemia-reperfusion (IR) and hemihepatectomy.

Methods

Eighteen healthy Bama miniature pigs were randomly divided into the sham-operated (sham), untreated IR injury (IRI), and ADSC-transplanted (ADSC) groups. Hepatic IR was established by laparoscopic hemihepatectomy. ADSCs were transplanted directly into the liver parenchyma after the surgery. Hepatic inflammation and liver regeneration were evaluated by histopathological examination and assessment of relevant cytokines and other factors.

Results

ADSC transplantation successfully ameliorated the IRI-induced histopathological damage and the high levels of pro-inflammatory cytokines like IL-1β, IL-6, and TNF-α. In addition, the ADSCs enhanced the expression of the anti-inflammatory IL-10, regenerative factors including HGF, Cyclin D1, and proliferating cell nuclear antigen (PCNA), and angiogenic factors like VEGF, ANG-1, and ANG-2.

Conclusions

ADSCs attenuated the hepatic IRI-induced inflammatory response and promoted liver regeneration.

The use of autologous fat grafts in breast surgery: A literature review

Autologous fat injection was first described roughly a century ago and has been used in surgery ever since. In addition to its use in many surgical fields, it is also frequently used for both aesthetic and reconstructive purposes in breast surgery. Since the application of fat grafting in breast surgery has steadily increased, studies investigating its reliability have simultaneously become increasingly common. Previous studies have reported that the use of fat grafting in breast surgery is reliable, but some pending questions remain about its routine use. In order to use fat grafts successfully in breast surgery, it is necessary to be familiar with the structure and content of adipose tissue, the efficacy of adipose stem cell-enriched fat grafts, the oncological safety of fat grafts, and the problems that may occur in the radiological follow-up of patients who undergo fat grafting procedures. In this literature review, we aim to discuss the use of fat grafts in breast surgery by investigating these common problems.

MicroRNA-145 Regulates the Differentiation of Adipose Stem Cells Toward Microvascular Endothelial Cells and Promotes Angiogenesis

RATIONALE

Adipose-derived stem cells (ASCs) are a potential adult mesenchymal stem cell source for restoring endothelial function in ischemic tissues. However, the mechanism that promotes ASCs differentiation toward endothelial cells (ECs) is not known.

OBJECTIVE

To investigate the mechanisms of ASCs differentiation into ECs.

METHODS AND RESULTS

ASCs were isolated from clinical lipoaspirates and cultured with DMEM or endothelial cell-conditioned medium. Endothelial cell-conditioned medium induced downregulation of miR-145 in ASCs and promoted endothelial differentiation. We identified bFGF (basic fibroblast growth factor) released by ECs as inducer of ASCs differentiation through receptor-induced AKT (protein kinase B) signaling and phosphorylation of FOXO1 (forkhead box protein O1) suppressing its transcriptional activity and decreasing miR-145 expression. Blocking bFGF-receptor or PI3K/AKT signaling in ASCs increased miR-145 levels. Modulation of miR-145 in ASCs, using a miR-145 inhibitor, regulated their differentiation into ECs: increasing proliferation, migration, inducing expression of EC markers (VE-cadherin, VEGFR2 [vascular endothelial growth factor receptor 2], or VWF [von Willebrand Factor]), and tube-like formation. Furthermore, in vivo, downregulation of miR-145 in ASCs enhanced angiogenesis in subcutaneously implanted plugs in mice. In a murine hindlimb ischemia model injection of ASCs with downregulated miR-145 induced collateral flow and capillary formation evidenced by magnetic resonance angiography. Next, we identified ETS1 (v-ets avian erythroblastosis virus E26 oncogene homolog 1) as the target of miR-145. Upregulation of miR-145 in ASCs, by mimic miR-145, suppressed ETS1 expression and consequently abolished EC differentiation and the angiogenic properties of endothelial cell-conditioned medium-preconditioned ASCs; whereas, overexpression of ETS1 reversed the abrogated antiangiogenic capacity of miR-145. ETS1 overexpression induced similar results to those obtained with miR-145 knockdown.

CONCLUSIONS

bFGF released by ECs induces ASCs differentiation toward ECs through miR-145-regulated expression of ETS1. Downregulation of miR-145 in ASCs induce vascular network formation in ischemic muscle.

Mesenchymal Stem Cells-Potential Applications in Kidney Diseases

Mesenchymal stem cells constitute a pool of cells present throughout the lifetime in numerous niches, characteristic of unlimited replication potential and the ability to differentiate into mature cells of mesodermal tissues in vitro. The therapeutic potential of these cells is, however, primarily associated with their capabilities of inhibiting inflammation and initiating tissue regeneration. Owing to these properties, mesenchymal stem cells (derived from the bone marrow, subcutaneous adipose tissue, and increasingly urine) are the subject of research in the settings of kidney diseases in which inflammation plays the key role. The most advanced studies, with the first clinical trials, apply to ischemic acute kidney injury, renal transplantation, lupus and diabetic nephropathies, in which beneficial clinical effects of cells themselves, as well as their culture medium, were observed. The study findings imply that mesenchymal stem cells act predominantly through secreted factors, including, above all, microRNAs contained within extracellular vesicles. Research over the coming years will focus on this secretome as a possible therapeutic agent void of the potential carcinogenicity of the cells.

Mesenchymal Stem Cells for Liver Regeneration in Liver Failure: From Experimental Models to Clinical Trials

The liver centralizes the systemic metabolism and thus controls and modulates the functions of the central and peripheral nervous systems, the immune system, and the endocrine system. In addition, the liver intervenes between the splanchnic and systemic venous circulation, determining an abdominal portal circulatory system. The liver displays a powerful regenerative potential that rebuilds the parenchyma after an injury. This regenerative mission is mainly carried out by resident liver cells. However, in many cases this regenerative capacity is insufficient and organ failure occurs. In normal livers, if the size of the liver is at least 30% of the original volume, hepatectomy can be performed safely. In cirrhotic livers, the threshold is 50% based on current practice and available data. Typically, portal vein embolization of the part of the liver that is going to be resected is employed to allow liver regeneration in two-stage liver resection after portal vein occlusion (PVO). However, hepatic resection often cannot be performed due to advanced disease progression or because it is not indicated in patients with cirrhosis. In such cases, liver transplantation is the only treatment possibility, and the need for transplantation is the common outcome of progressive liver disease. It is the only effective treatment and has high survival rates of 83% after the first year. However, donated organs are becoming less available, and mortality and the waiting lists have increased, leading to the initiation of living donor liver transplantations. This type of transplant has overall complications of 38%. In order to improve the treatment of hepatic injury, much research has been devoted to stem cells, in particular mesenchymal stem cells (MSCs), to promote liver regeneration. In this review, we will focus on the advances made using MSCs in animal models, human patients, ongoing clinical trials, and new strategies using 3D organoids.

Insulin-like growth factor-I promotes hepatic differentiation of human adipose tissue-derived stem cells

There are numerous studies which provide support for the use of human adipose tissue-derived stem cells (hASCs) to generate hepatocyte-like cells. However, the produced cells exhibit only a certain level of differentiation, mainly due to inefficient induction conditions. Therefore, based on the important role of insulin-like growth factor (IGF-I) in hepatic function and development, in the current study we evaluated the differentiation efficacy of the mentioned factor to induce hASCs into functional hepatocyte-like cells. To investigate this, using a two-step protocol, hASCs were treated with a combination of HGF, Dex, and OSM in the presence or absence of IGF-I up to 21 days. Hepatic differentiation was evaluated by analyzing specific hepatocyte markers at different time points of differentiation induction. Increased expression of hepatocyte-specific genes including ALB, AFP, CK18, and HNF4a, downregulation of bile duct cells marker (CK19), the higher number of ALB positive cells, increased urea production together with higher glycogen deposit was observed upon the treatment of hASCs with the induction medium containing IGF-I compared to the other treatment. In conclusion, our findings suggest IGF-I as a potent inducer of hepatic differentiation of hASCs and its potential to generate more functional hepatocyte-like cells.

An updated review of adipose derived-mesenchymal stem cells and their applications in musculoskeletal disorders

INTRODUCTION

Adipose-derived mesenchymal stem cells (ASCs) represent a new therapeutic strategy in biomedicine with many potential applications, especially in musculoskeletal disorders. Preclinical and clinical studies based on the administration of ASCs support their efficacy in bone regeneration, joint repair, tendon injury and skeletal muscle alterations. Many of these novel treatments may improve patients' quality of life and prognosis. However, several concerns about the use of stem cells remain unsolved, particularly regarding their safety and side effects. The present work aims to review the nature, clinical trials and patents involving the use of ASCs in musculoskeletal disorders.

AREAS COVERED

In this article, we describe ASCs' isolation, culture and differentiation in vivo and in vitro, advances on ASCs' applications in bone, cartilage, muscle and tendon repair, and patents involving the use of ASCs.

EXPERT OPINION

The use of ASCs in musculoskeletal disorders presents significant therapeutic advantages, including limited autoimmune response, potential cell expansion ex vivo, high plasticity to differentiate into several mesodermal cell lineages, and additional effects of therapeutic interest such as secretion of neurotrophic factors and anti-inflammatory properties. For these reasons, ASCs are promising therapeutic agents for clinical applications in musculoskeletal disorders.

Liver Macrophage Depletion Ameliorates The Effect of Mesenchymal Stem Cell Transplantation in a Murine Model of Injured Liver

Mesenchymal stem cells (MSCs) therapy show different levels of effectiveness in the context of different types of liver damage, suggesting that the microenvironment of the injured liver is a key determinant for effective stem cell therapy. The objective was to assess the modulatory effect of hepatic stem cell niche components on the transplanted MSCs during liver injury induced by carbon tetrachloride (CCl₄). Superparamagnetic iron oxide (SPIO)-labeled human MSCs were injected intravenously into mice treated with CCl₄ and subjected to hepatic macrophage-depletion. Liver tissues were collected at different intervals post transplantation for subsequent histopathological, morphometric, immunohistochemical, gene expression and ultrastructural studies. The homing of the transplanted MSCs was evidenced by tracing them within the niche by iron staining and immunohistochemical studies. MSCs differentiated into hepatocyte-like cells and intimal smooth muscle cells as evidenced by their expression of human albumin and α-smooth muscle actin with a concomitant increase in the level of mouse hepatocyte growth factor. A post transplantation reduction in the liver fibro-inflammatory reaction was found and was promoted by liver macrophages depletion. Thus, it could be concluded from the present study that prior manipulation of the microenvironment is required to improve the outcome of the transplanted cells.

Methods and Strategies for Procurement, Isolation, Characterization, and Assessment of Senescence of Human Mesenchymal Stem Cells from Adipose Tissue

Human adipose-derived mesenchymal stem (stromal) cells (hADSC) represent an attractive source of the cells for numerous therapeutic applications in regenerative medicine. These cells are also an efficient model to study biological pathways of stem cell action, tissue injury and disease. Like any other primary somatic cells in culture, industrial-scale expansion of mesenchymal stromal cells (MSC) leads to the replicative exhaustion/senescence as defined by the "Hayflick limit." The senescence is not only greatly effecting in vivo potency of the stem cell cultures but also might be the cause and the source of clinical inconsistency arising from infused cell preparations. In this light, the characterization of hADSC replicative and stressor-induced senescence phenotypes is of great interest.This chapter summarizes some of the essential protocols and assays used at our laboratories and clinic for the human fat procurement, isolation, culture, differentiation, and characterization of mesenchymal stem cells from adipose tissue and the stromal vascular fraction. Additionally, we provide manuals for characterization of hADSC senescence in a culture based on stem cells immunophenotype, proliferation rate, migration potential, and numerous other well-accepted markers of cellular senescence. Such methodological framework will be immensely helpful to design standards and surrogate measures for hADSC-based therapeutic applications.

Adipose-derived stem cells alleviate liver apoptosis induced by ischemia-reperfusion and laparoscopic hepatectomy in swine

Hepatic ischemia-reperfusion (I/R) injury is inevitable during hepatectomy and may cause both postoperative morbidity and mortality. Regenerative medicine suggested adipose-derived stem cells (ADSCs) as an attractive tool for the treatment of liver diseases. In this study, we investigated the effect of ADSCs in an I/R model combined with laparoscopic hepatectomy in swine. Eighteen Bama miniature pigs were randomly divided into Sham, IRI, and ADSCs groups. ADSCs (1 × 10⁶/kg) were injected through liver parenchyma immediately after hemihepatectomy. The apoptosis-related role of ADSCs was studied. The results showed that ADSCs transplantation reduced both pathological and ultrastructural changes and decreased the number of apoptotic-positive cells. In the ADSCs group, Fas, Fas ligand (FasL) protein, and mRNA were downregulated and the enzyme activities of Caspase3, Caspase8, and Caspase9 were significantly decreased. In addition, ADSC therapy significantly increased the ratio of Bcl-2/Bax protein and mRNA compared to the IRI group. In conclusion, ADSCs attenuated both I/R and hepatectomy-induced liver apoptosis in a porcine model, and offers a potential therapeutic option for hepatic I/R and hepatectomy.

Autologous fat grafting: Latest insights

A recent rise in the use of autologous fat transfer for soft tissue augmentation has paralleled the increasing popularity of liposuction body contouring. This creates a readily available and inexpensive product for lipografting, which is the application of lipoaspirated material. Consistent scientific proof about the long-term viability of the transferred fat is not available. Clinically, there is a reabsorption rate which has been reported to range from 20 to 90%. Results can be unpredictable with overcorrection and regular need for additional interventions. In this review, adipogenesis physiology and the adipogenic cascade from adipose-derived stem cells to adult adipocytes is extensively described to determine various procedures involved in the fat grafting technique. Variables in structure and physiology, adipose tissue harvesting- and processing techniques, and the preservation of fat grafts are taken into account to collect reproducible scientific data to establish standard in vitro and in vivo models for experimental fat grafting. Adequate histological staining for fat tissue, immunohistochemistry and viability assays should be universally used in experiments to be able to produce comparative results. By analysis of the applied methods and comparison to similar experiments, a conclusion concerning the ideal technique to improve clinical outcome is proposed.

•

Adipogenic physiology is described to determine various procedures involved in the fat grafting technique.

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Clinical studies on fat grafting have confirmed an unpredictable result.

•

After analysis of the literature and despite attempts to eliminate confounding factors, on every step of the fat transfer technique a number of studies with conflicting results exist.

•

Adequate histological staining for fat tissue, immunohistochemistry and viability assays should be universally used in experiments to be able to produce comparative results.

In Vivo Imaging Technology of Transplanted Stem Cells Using Quantum Dots for Regenerative Medicine

Quantum dots (QDs) have excellent fluorescence properties in comparison to traditional fluorescence probes. Thus, the optical application of QDs is rapidly expanding to each field of analytical chemistry. In this review paper, we reviewed the application of QDs to regenerative medicine, especially stem cell transplantation therapy. The labeling of stem cells using QDs composed of semiconductor materials in combination with a chemical substance, poly-cationic liposome and cell penetrating peptide is reported. In addition, the influence of QD labeling on the pluripotency of stem cells is also reported. Finally, the in vivo imaging of transplanted stem cells in mice by QDs emitting fluorescence in the near-infrared region, which can be detected by in vivo fluorescence imaging systems such as IVIS and SAI-1000, is described. The future prospects for stem cell imaging technology by QDs are also discussed.

Label-Free Rapid Separation and Enrichment of Bone Marrow-Derived Mesenchymal Stem Cells from a Heterogeneous Cell Mixture Using a Dielectrophoresis Device

Bone marrow-derived mesenchymal stem cells (BMSCs) are an important cell resource for stem cell-based therapy, which are generally isolated and enriched by the density-gradient method based on cell size and density after collection of tissue samples. Since this method has limitations with regards to purity and repeatability, development of alternative label-free methods for BMSC separation is desired. In the present study, rapid label-free separation and enrichment of BMSCs from a heterogeneous cell mixture with bone marrow-derived promyelocytes was successfully achieved using a dielectrophoresis (DEP) device comprising saw-shaped electrodes. Upon application of an electric field, HL-60 cells as models of promyelocytes aggregated and floated between the saw-shaped electrodes, while UE7T-13 cells as models of BMSCs were effectively captured on the tips of the saw-shaped electrodes. After washing out the HL-60 cells from the device selectively, the purity of the UE7T-13 cells was increased from 33% to 83.5% within 5 min. Although further experiments and optimization are required, these results show the potential of the DEP device as a label-free rapid cell isolation system yielding high purity for rare and precious cells such as BMSCs.

Ameliorating effect of encapsulated hepatocyte-like cells derived from umbilical cord in high mannuronic alginate scaffolds on acute liver failure in rats

OBJECTIVES

In this study, effects of encapsulated umbilical cord stem cells (UCSCs)-derived hepatocyte-like cells (HLCs) in high mannuronic alginate scaffolds was investigated on CCl4-induced acute liver failure (ALF) in rats.

MATERIAL AND METHODS

UCSCs were encapsulated in high mannuronic alginate scaffolds. Then the UCSCs differentiated into HLCs for treatment of CCl4-induced ALF in rats. Thirty rats randomly divided into 5 groups: Intoxicated group received only CCl4 to induce ALF. In other groups including cell-free, UCSCs and HLCs, alginate scaffolds were transplanted into the liver 4 days after CCl4 injection. Biochemical markers including albumin (ALB), blood urea nitrogen (BUN), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were evaluated. Histological changes and gene expression of ALB, alpha-fetoprotein (AFP), and cytokeratin 18 (CK-18) were also assessed.

RESULTS

Expression of CK-18 significantly increased in HLCs compared to the UCSCs in vitro. This indicates that UCSCs can effectively differentiate into the HLCs. In CCl4-intoxicated group, BUN, AST and ALT levels, and histological criteria, such as infiltration of inflammatory cells, accumulation of reticulocytes, nuclear pyknosis of hepatocyte and sinusoidal dilation, significantly increased. In this group, ALB secretion significantly decreased, while AFP expression significantly increased. Both UCSCs and HLCs encapsulated in alginate scaffolds effectively attenuated biochemical tests, improved liver cytoarchitecture, increased expression of ALB and reduced AFP expression.

CONCLUSION

Finding of the present study indicated that encapsulation of UCSCs or HLCs in alginate mannuronic scaffolds effectively improve CCl4-induced ALF.