Potential application of cord blood-derived stromal cells in cellular therapy and regenerative medicine

Umbilical cord blood metabolomics reveal distinct signatures of dyslipidemia prior to bronchopulmonary dysplasia and pulmonary hypertension

Pulmonary hypertension (PH) is a common consequence of bronchopulmonary dysplasia (BPD) and remains a primary contributor to increased morbidity and mortality among preterm infants. Unfortunately, at the present time, there are no reliable early predictive markers for BPD-associated PH. Considering its health consequences, understanding in utero perturbations that lead to the development of BPD and BPD-associated PH and identifying early predictive markers is of utmost importance. As part of the discovery phase, we applied a multiplatform metabolomics approach consisting of untargeted and targeted methodologies to screen for metabolic perturbations in umbilical cord blood (UCB) plasma from preterm infants that did ( n = 21; cases) or did not ( n = 21; controls) develop subsequent PH. A total of 1,656 features were detected, of which 407 were annotated by metabolite structures. PH-associated metabolic perturbations were characterized by reductions in major choline-containing phospholipids, such as phosphatidylcholines and sphingomyelins, indicating altered lipid metabolism. The reduction in UCB abundances of major choline-containing phospholipids was confirmed in an independent validation cohort consisting of UCB plasmas from 10 cases and 10 controls matched for gestational age and BPD status. Subanalyses in the discovery cohort indicated that elevations in the oxylipins PGE1, PGE2, PGF2a, 9- and 13-HOTE, 9- and 13-HODE, and 9- and 13-KODE were positively associated with BPD presence and severity. This expansive evaluation of cord blood plasma identifies compounds reflecting dyslipidemia and suggests altered metabolite provision associated with metabolic immaturity that differentiate subjects, both by BPD severity and PH development.

Osteoconduction of Unrestricted Somatic Stem Cells on an Electrospun Polylactic-Co-Glycolic Acid Scaffold Coated with Nanohydroxyapatite

The limitation of traditional bone grafts could be overcome by applying engineered bone constructs, which are mainly produced by seeding suitable stem cells on appropriate scaffolds. So far, bone marrow-derived stromal cells have been the most applied cells in bone tissue engineering, but current data show that unrestricted somatic stem cells (USSCs) from human cord blood might actually be a better stem cell source due to the accessibility and noninvasive procedure of collection. In this study, we cultured USSCs on a plasma-treated electrospun polylactic-co-glycolic acid (PLGA) scaffold coated with nanohydroxyapatite (nHA). Adhesion and proliferation of USSCs on PLGA/nHA were assessed by scanning electron microscopy and MTT assay. Osteogenic differentiation of USSCs into osteoblast lineage cells was evaluated via alkaline phosphatase (ALP) activity and real-time polymerase chain reaction. Our observation showed that USSCs attached and proliferated on PLGA/nHA. Osteogenic differentiation was confirmed by increased ALP activity and OSTEONECTIN expression in USSCs on PLGA/nHA after the 1st week of the osteogenic period. Therefore, using USSCs on electrospun PLGA/nHA is a promising approach in bone tissue engineering.

The use of stem cells in aesthetic dermatology and plastic surgery procedures. A compact review of experimental and clinical applications

The aim of this paper was to collect currently available data related to the use of stem cells in aesthetic dermatology and plastic surgery based on a systemic review of experimental and clinical applications. We found that the use of stem cells is very promising but the current state of art is still not effective. This situation is connected with not fully known mechanisms of cell interactions, possible risks and side effects. We think that there is a big need to create and conduct different studies which could resolve problems of stem cells use for implementation into aesthetic dermatology and plastic surgery.

Low oxygen tension reveals distinct HOX codes in human cord blood-derived stromal cells associated with specific endochondral ossification capacities in vitro and in vivo

Effects of oxygen tension on the generation, expansion, proliferation and differentiation of stromal cell types is widely described in the literature. However, data on the internal heterogeneity of applied cell populations at different O₂ levels and possible impacts on differentiation potentials are controversial. Here, the expression of 39 human HOX genes was determined in neonatal cord blood stromal cells and linked to differentiation-associated signatures. In cord blood, unrestricted somatic stromal cells (USSCs), lacking HOX gene expression, and cord blood-derived multipotent stromal cells (CB-MSCs), expressing about 20 HOX genes, are distinguished by their specific HOX code. Interestingly, 74% of the clones generated at 21% O₂ were HOX-negative USSCs, whereas 73% of upcoming clones at 3% O₂ were HOX-positive CB-MSCs. In order to better categorize distinct cell lines generated at 3% O₂ , the expression of all 39 HOX genes within HOX clusters A, B, C and D were tested and new subtypes defined: cells negative in all four HOX clusters (USSCs); cells positive in all four clusters (CB-MSCs^ABCD ); and subpopulations missing a single cluster (CB-MSCs^ACD and CB-MSCs^BCD ). Comprehensive qPCR analyses of established chondro-osteomarkers revealed subtype-specific signatures verifiably associated with in vitro and in vivo differentiation capacity. The data presented here underline the necessity of better characterizing distinct cell populations at a clonal level, taking advantage of the inherent specific HOX code as a distinguishing feature between individual subtypes. Moreover, the correlation of subtype-specific molecular signatures with in vitro and in vivo bone formation is discussed. Copyright © 2016 John Wiley & Sons, Ltd.

Stem Cells: Potential Therapy for Neonatal Injury?

Stem cell transplantation (SCT) is an established first-line or adjunctive therapy for a variety of neonatal and adult diseases. New evidence in preclinical models as well as a few human studies show the potential utility of SCT in neuroprotection and in the modulation of inflammatory injury in at risk-neonates. This review briefly summarizes current understanding of human stem cell biology during ontogeny and present recent evidence supporting SCT as a viable approach for postinsult neonatal injury.

DNA damage response in neonatal and adult stromal cells compared with induced pluripotent stem cells

Comprehensive analyses comparing individual DNA damage response (DDR) of induced pluripotent stem cells (iPSCs) with neonatal stromal cells with respect to their developmental age are limited. The imperative necessity of providing developmental age-matched cell sources for meaningful toxicological drug safety assessments in replacement of animal-based testing strategies is evident. Here, DDR after radiation or treatment with N-methyl-N-nitrosurea (MNU) was determined in iPSCs compared with neonatal and bone marrow stromal cells. Neonatal and adult stromal cells showed no significant morphologically detectable cytotoxicity following treatment with 1 Gy or 1 mM MNU, whereas iPSCs revealed a much higher sensitivity. Foci analyses revealed an effective DNA repair in stromal cell types and iPSCs, as reflected by a rapid formation and disappearance of phosphorylated ATM and γH2AX foci. Furthermore, quantitative polymerase chain reaction analyses revealed the highest basic expression level of DDR and repair-associated genes in iPSCs, followed by neonatal stromal cells and adult stromal cells with the lowest expression levels. In addition, the influence of genotoxic stress prior to and during osteogenic differentiation of neonatal and adult stromal cells was analyzed applying common differentiation procedures. Experiments presented here suggest a developmental age-dependent basic expression level of genes involved in the processing of DNA damage. In addition a differentiation-dependent downregulation of repair genes was observed during osteogenesis. These results strongly support the requirement to provide adequate cell sources for toxicological in vitro drug testing strategies that match to the developmental age and differentiation status of the presumptive target cell of interest.

SIGNIFICANCE

The results obtained in this study advance the understanding of DNA damage processing in human neonatal stromal cells as compared with adult stromal cells and induced pluripotent stem cells (iPSCs). The data suggest developmental age-dependent differences in DNA damage repair capacity. In iPSCs (closest to embryonic stem cells), the highest expression level of DNA damage response and repair genes was found, followed by neonatal stromal cells and adult stromal cells with the lowest overall expression. In addition, a differentiation-dependent downregulation of repair capacity was observed during osteogenic differentiation in neonatal stromal cells. Notably, the impact of genotoxic stress on osteogenic differentiation depended on the time the genotoxic insult took place and, moreover, was agent-specific. These results strongly support the necessity of offering and establishing adequate cell sources for informative toxicological testing matching to the developmental age and differentiation status of the respective cell of interest.

Mir-302 cluster exhibits tumor suppressor properties on human unrestricted somatic stem cells

Many studies have reported that miR-302-367 cluster acts in different ways in various cell types. For instance, this cluster is shown to have a potential role in stemness regulation in embryonic stem cells (ESCs). On the other hand, this cluster inhibits the tumorigenicity of human pluripotent stem cells by coordinated suppression of CDK2 and CDK4/6 cell cycle pathways. Indeed, this cluster has a significant posttranscriptional impact on cell cycle progression. Previous reports have shown the participation of miR-302-367 cluster in cell cycle regulation of hESCs, MCF7, HepG2, and Teta-2 embryonal teratocarcinoma cells, but its effect on unrestricted somatic stem cells (USSCs) as a new source of human somatic stem cells from the umbilical cord blood remains to be elucidated. Therefore, in this study, we aimed to investigate the effect of miR-302-367 cluster on cell proliferation by MTT assay, cell cycle analysis, and colony formation assay. In addition, the expression of candidate cell cycle regulatory performance and tumor suppressor genes was determined. In this study, for the first time, we found that miR-302-367 cluster not only did not reprogram human USSCs into a pluripotent ESC-like state, but also inhibited the proliferation of human USSCs. Moreover, analyzing the cell cycle curve revealed a significant apoptotic phase upon viral introduction of miR-302-367. Our gene expression study revealed the overexpression of candidate genes after transduction of USSCs with miR-302-367 cluster. In conclusion, the controversial role of miR-302-367 in different cell types may provide better understanding for its role in stemness level and its antitumorigenicity potential in different contexts.

Use of umbilical cord and cord blood-derived stem cells for tissue repair and regeneration

INTRODUCTION

Potential use of umbilical cord (UC) is one of the most exciting frontiers in medicine for repairing damaged tissues. UC and cord blood-derived stem cells are the world's largest potential sources of stem cells. UC contains a mixture of stem and progenitor cells at different lineage commitment stages and UC has been verified as a candidate for cell-based therapies and tissue engineering applications due to the capability of these cells for extensive self-renewal and multi-lineage character in differentiation potential.

AREAS COVERED

UC-based repair or regeneration of organs (i.e., heart, nerve, skin, etc.) is a high-priority research worldwide.

EXPERT OPINION

The aim of this review is to summarize the knowledge about UC with main focus on its applications for tissue repair and regeneration.