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Muenke syndrome is the leading genetic cause of craniosynostosis and results in a variety of disabling clinical phenotypes. To model the disease and study the pathogenic mechanisms, a human induced pluripotent stem cell (hiPSC) line was generated from a patient diagnosed with Muenke syndrome. Successful reprogramming was validated by morphological features, karyotyping, loss of reprogramming factors, expression of pluripotency markers, mutation analysis and teratoma formation., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest., (Published by Elsevier B.V.)

Background: Bone marrow stromal or stem cells (BMSCs) remain a promising potential therapy for ischemic cardiomyopathy. The primary objective of this study was to evaluate the safety and feasibility of direct intramyocardial injection of autologous BMSCs in patients undergoing transmyocardial revascularization (TMR) or coronary artery bypass graft surgery (CABG)., Methods: A phase I trial was conducted on adult patients who had ischemic heart disease with depressed left ventricular ejection fraction and who were scheduled to undergo TMR or CABG. Autologous BMSCs were expanded for 3 weeks before the scheduled surgery. After completion of surgical revascularization, BMSCs were directly injected into ischemic myocardium. Safety and feasibility of therapy were assessed. Cardiac functional status and changes in quality of life were evaluated at 1 year., Results: A total of 14 patients underwent simultaneous BMSC and surgical revascularization therapy (TMR+BMSCs = 10; CABG+BMSCs = 4). BMSCs were successfully expanded, and no significant complications occurred as a result of the procedure. Regional contractility in the cell-treated areas demonstrated improvement at 12 months compared with baseline (TMR+BMSCs Δ strain: -4.6% ± 2.1%; P = .02; CABG+MSCs Δ strain: -4.2% ± 6.0%; P = .30). Quality of life was enhanced, with substantial reduction in angina scores at 1 year after treatment (TMR+BMSCs: 1.3 ± 1.2; CABG+MSCs: 1.0 ± 1.4)., Conclusions: In this phase I trial, direct intramyocardial injection of autologous BMSCs in conjunction with TMR or CABG was technically feasible and could be performed safely. Preliminary results demonstrate improved cardiac function and quality of life in patients at 1 year after treatment., (Copyright © 2020 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Patients with systemic mastocytosis (SM) have a wide variety of problems, including skeletal abnormalities. The disease results from a mutation of the stem cell receptor (c-kit) in mast cells and we wondered if the function of bone marrow stromal cells (BMSCs; also known as MSCs or mesenchymal stem cells) might be affected by the invasion of bone marrow by mutant mast cells. As expected, BMSCs from SM patients do not have a mutation in c-kit, but they proliferate poorly. In addition, while osteogenic differentiation of the BMSCs seems to be deficient, their adipogenic potential appears to be increased. Since the hematopoietic supportive abilities of BMSCs are also important, we also studied the engraftment in NSG mice of human CD34(+) hematopoietic progenitors, after being co-cultured with BMSCs of healthy volunteers vs. BMSCs derived from patients with SM. BMSCs derived from the bone marrow of patients with SM could not support hematopoiesis to the extent that healthy BMSCs do. Finally, we performed an expression analysis and found significant differences between healthy and SM derived BMSCs in the expression of genes with a variety of functions, including the WNT signaling, ossification, and bone remodeling. We suggest that some of the symptoms associated with SM might be driven by epigenetic changes in BMSCs caused by dysfunctional mast cells in the bone marrow of the patients., (Published by Elsevier B.V.)

Background Aims: Ex vivo expansion and serial passage of human bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells) is required to obtain sufficient quantities for clinical therapy. The BMSC confluence criteria used to determine passage and harvest timing vary widely, and the impact of confluence on BMSC properties remains controversial. The effects of confluence on BMSC properties were studied and confluence-associated markers were identified., Methods: BMSC characteristics were analyzed as they grew from 50% to 100% confluence, including viability, population doubling time, apoptosis, colony formation, immunosuppression, surface marker expression, global gene expression and microRNA expression. In addition, culture supernatant protein, glucose, lactate and pH levels were analyzed., Results: Confluence-dependent changes were detected in the expression of several cell surface markers: 39 culture supernatant proteins, 26 microRNAs and 2078 genes. Many of these surface markers, proteins, microRNAs and genes have been reported to be important in BMSC function. The pigment epithelium-derived factor/vascular endothelial growth factor ratio increased with confluence, but 80% and 100% confluent BMSCs demonstrated a similar level of immunosuppression of mixed lymphocyte reactions. In addition, changes in lactate and glucose levels correlated with BMSC density., Conclusions: BMSC characteristics change as confluence increases. 100% confluent BMSCs may have compromised pro-angiogenesis properties but may retain their immunomodulatory properties. Supernatant lactate and glucose levels can be used to estimate confluence and ensure consistency in passage and harvest timing. Flow cytometry or microRNA expression can be used to confirm that the BMSCs have been harvested at the appropriate confluence., (Published by Elsevier Inc.)

Bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells) are fibroblastic reticular cells, a subset of which is composed of multipotent skeletal stem cells (SSCs). SSCs/BMSCs are able to recreate a bone/marrow organ in vivo. To determine differences between clonogenic multipotent SSCs and similarly clonogenic but non-multipotent BMSCs, we established single colony-derived strains (SCDSs, initiated by individual Colony Forming Unit-Fibroblasts) and determined their differentiation capacity by vivo transplantation. In this series of human SCDSs (N=24), 20.8% formed fibrous tissue (F), 66.7% formed bone (B), and 12.5% formed a bone/marrow organ, and thus were multipotent (M). RNA isolated from 12 SCDSs just prior to transplantation was analyzed by microarray. Although highly similar, there was variability from one SCDS to another, and SCDSs did not strictly segregate into the three functional groups (F, B or M) by unsupervised hierarchical clustering. We then compared 3 F-SCDSs to 3 M-SCDSs that did segregate. Genes associated with skeletogenesis, osteoblastogeneis, hematopoiesis, and extracellular matrix were over-represented in M-SCDSs compared with F-SCDSs. These results highlight the heterogeneity of SSCs/BMSCs, even between functionally similar SCDSs, but also indicate that differences can be detected that may shed light on the character of the SSC., (Published by Elsevier B.V.)

Dyskeratosis congenita (DC) is an inherited multisystem disorder, characterized by oral leukoplakia, nail dystrophy, and abnormal skin pigmentation, as well as high rates of bone marrow (BM) failure, solid tumors, and other medical problems such as osteopenia. DC and telomere biology disorders (collectively referred to as TBD here) are caused by germline mutations in telomere biology genes leading to very short telomeres and limited proliferative potential of hematopoietic stem cells. We found that skeletal stem cells (SSCs) within the BM stromal cell population (BMSCs, also known as BM-derived mesenchymal stem cells), may contribute to the hematologic phenotype. TBD-BMSCs exhibited reduced clonogenicity, spontaneous differentiation into adipocytes and fibrotic cells, and increased senescence in vitro. Upon in vivo transplantation into mice, TBD-BMSCs failed to form bone or support hematopoiesis, unlike normal BMSCs. TERC reduction (a TBD-associated gene) in normal BMSCs by small interfering TERC-RNA (siTERC-RNA) recapitulated the TBD-BMSC phenotype by reducing proliferation and secondary colony-forming efficiency, and by accelerating senescence in vitro. Microarray profiles of control and siTERC-BMSCs showed decreased hematopoietic factors at the messenger RNA level and decreased secretion of factors at the protein level. These findings are consistent with defects in SSCs/BMSCs contributing to BM failure in TBD.

Human pluripotent stem cells (hPSCs) have two potentially attractive applications: cell replacement-based therapies and drug discovery. Both require the efficient generation of large quantities of clinical-grade stem cells that are free from harmful genomic alterations. The currently employed colony-type culture methods often result in low cell yields, unavoidably heterogeneous cell populations, and substantial chromosomal abnormalities. Here, we shed light on the structural relationship between hPSC colonies/embryoid bodies and early-stage embryos in order to optimize current culture methods based on the insights from developmental biology. We further highlight core signaling pathways that underlie multiple epithelial-to-mesenchymal transitions (EMTs), cellular heterogeneity, and chromosomal instability in hPSCs. We also analyze emerging methods such as non-colony type monolayer (NCM) and suspension culture, which provide alternative growth models for hPSC expansion and differentiation. Furthermore, based on the influence of cell-cell interactions and signaling pathways, we propose concepts, strategies, and solutions for production of clinical-grade hPSCs, stem cell precursors, and miniorganoids, which are pivotal steps needed for future clinical applications., (Published by Elsevier B.V.)

Matrix proteoglycans such as biglycan (Bgn) dominate skeletal tissue and yet its exact role in regulating bone function is still unclear. In this paper we describe the potential role of (Bgn) in the fracture healing process. We hypothesized that Bgn could regulate fracture healing because of previous work showing that it can affect normal bone formation. To test this hypothesis, we created fractures in femurs of 6-week-old male wild type (WT or Bgn+/0) and Bgn-deficient (Bgn-KO or Bgn-/0) mice using a custom-made standardized fracture device, and analyzed the process of healing over time. The formation of a callus around the fracture site was observed at both 7 and 14 days post-fracture in WT and Bgn-deficient mice and immunohistochemistry revealed that Bgn was highly expressed in the fracture callus of WT mice, localizing within woven bone and cartilage. Micro-computed tomography (μCT) analysis of the region surrounding the fracture line showed that the Bgn-deficient mice had a smaller callus than WT mice. Histology of the same region also showed the presence of less cartilage and woven bone in the Bgn-deficient mice compared to WT mice. Picrosirius red staining of the callus visualized under polarized light showed that there was less fibrillar collagen in the Bgn-deficient mice, a finding confirmed by immunohistochemistry using antibodies to type I collagen. Interestingly, real time RT-PCR of the callus at 7 days post-fracture showed a significant decrease in relative vascular endothelial growth factor A (VEGF) gene expression by Bgn-deficient mice as compared to WT. Moreover, VEGF was shown to bind directly to Bgn through a solid-phase binding assay. The inability of Bgn to directly enhance VEGF-induced signaling suggests that Bgn has a unique role in regulating vessel formation, potentially related to VEGF storage or stabilization in the matrix. Taken together, these results suggest that Bgn has a regulatory role in the process of bone formation during fracture healing, and further, that reduced angiogenesis could be the molecular basis., (Published by Elsevier B.V.)

Many studies have compared the genetic and epigenetic profiles of human induced pluripotent stem cells (hiPSCs) to human embryonic stem cells (hESCs) and yet the picture remains unclear. To address this, we derived a population of neural precursor cells (NPCs) from the H1 (WA01) hESC line and generated isogenic iPSC lines by reprogramming. The gene expression and methylation profile of three lines were compared to the parental line and intermediate NPC population. We found no gene probe with expression that differed significantly between hESC and iPSC samples under undifferentiated or differentiated conditions. Analysis of the global methylation pattern also showed no significant difference between the two PSC populations. Both undifferentiated populations were distinctly different from the intermediate NPC population in both gene expression and methylation profiles. One point to note is that H1 is a male line and so extrapolation to female lines should be cautioned. However, these data confirm our previous findings that there are no significant differences between hESCs and hiPSCs at the gene expression or methylation level., (Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.)

The outcomes of clinical trials using bone marrow stromal cell (BMSC) are variable; the degree of the expansion of BMSCs during clinical manufacturing may contribute to this variability since cell expansion is limited by senescence. Human BMSCs from aspirates of healthy subjects were subcultured serially until cell growth stopped. Phenotype and functional measurements of BMSCs from two subjects including senescence-associated beta-galactosidase staining and colony formation efficiency changed from an early to a senescence pattern at passage 6 or 7. Transcriptome analysis of 10 early and 15 late passage BMSC samples from 5 subjects revealed 2122 differentially expressed genes, which were associated with immune response, development, and cell proliferation pathways. Analysis of 57 serial BMSC samples from 7 donors revealed that the change from an early to senescent profile was variable among subjects and occurred prior to changes in phenotypes. BMSC age expressed as a percentage of maximum population doublings (PDs) was a good indicator for an early or senescence transcription signature but this measure of BMSC life span can only be calculated after expanding BMSCs to senescence. In order to find a more useful surrogate measure of BMSC age, we used a computational biology approach to identify a set of genes whose expression at each passage would predict elapsed age of BMSCs. A total of 155 genes were highly correlated with BMSC age. A least angle regression algorithm identified a set of 24 BMSC age-predictive genes. In conclusion, the onset of senescence-associated molecular changes was variable and preceded changes in other indicators of BMSC quality and senescence. The 24 BMSC age predictive genes will be useful in assessing the quality of clinical BMSC products., (© 2013.)

Regenerative medicine, relying on human embryonic stem cell (hESC) technology, opens promising new avenues for therapy of many severe diseases. However, this approach is restricted by limited production of the desired cells due to the refractory properties of hESC growth in vitro. It is further hindered by insufficient control of cellular stress, growth rates, and heterogeneous cellular states under current culture conditions. In this study, we report a novel cell culture method based on a non-colony type monolayer (NCM) growth. Human ESCs under NCM remain pluripotent as determined by teratoma assays and sustain the potential to differentiate into three germ layers. This NCM culture has been shown to homogenize cellular states, precisely control growth rates, significantly increase cell production, and enhance hESC recovery from cryopreservation without compromising chromosomal integrity. This culture system is simple, robust, scalable, and suitable for high-throughput screening and drug discovery., (Published by Elsevier B.V.)

Background Aims: Bone marrow stromal cells (BMSC) are being used for immune modulatory, anti-inflammatory and tissue engineering applications, but the properties responsible for these effects are not completely understood. Human BMSC were characterized to identify factors that might be responsible for their clinical effects and biomarkers for assessing their quality., Methods: Early passage BMSC prepared from marrow aspirates of seven healthy subjects were compared with three human embryonic stem cell (hESC) samples, CD34(+) cells from three healthy subjects and three fibroblast cell lines. The cells were analyzed with oligonucleotide expression microarrays with more than 35 000 probes., Results: BMSC gene expression signatures of BMSC differed from those of hematopoietic stem cells (HSC), hESC and fibroblasts. Genes upregulated in BMSC were involved with cell movement, cell-to-cell signaling and interaction and proliferation. The upregulated genes most probably belonged to pathways for integrin signaling, integrin-linked kinase (ILK) signaling, NF-E2-related factor-2 (NFR2)-mediated oxidative stress response, regulation of actin-based motility by Rho, actin cytoskeletal signaling, caveolar-mediated endocytosis, clathrin-mediated endocytosis and Wingless-type MMTV integration site (Wnt/β catenin signaling. Among the most highly upregulated genes were structural extracellular matrix (ECM) proteins (α5 and β5 integrin chains, fibronectin and collagen type IIIα1 and Vα1) and functional EMC proteins [connective tissue growth factor (CTGF), transforming growth factor beta-induced protein (TGFBI) and A disintegrin and metalloproteinase (ADAM12)]., Conclusions: Global analysis of human BMSC suggests that they are mobile, metabolically active, proliferative and interactive cells that make use of integrins and integrin signaling. They produce abundant ECM proteins that may contribute to their clinical immune modulatory and anti-inflammatory effects.

Bone marrow stromal cell populations, containing a subset of multipotential skeletal stem cells, are increasingly contemplated for use in tissue engineering and stem cell therapy, whereas their involvement in the pathogenetic mechanisms of skeletal disorders is far less recognized. We compared the concentrations of stromal clonogenic cells, colony forming units-fibroblast (CFU-Fs), in norm and pathology. Initially, culture conditions were optimized by demonstrating that fetal bovine serum heat inactivation could significantly repress colony formation. Using non-heat-inactivated fetal bovine serum, the concentration of CFU-Fs (colony-forming efficiency, CFE) ranged from 3.5 +/- 1.0 to 11.5 +/- 4.0 per 1 x 10(5) nucleated cells in five inbred mouse strains. In four transgenic lines with profound bone involvement, CFE was either significantly reduced or increased compared to wild-type littermates. In normal human donors, CFE decreased slightly with age and averaged 52.2 +/- 4.1 for children and 32.3 +/- 3.0 for adults. CFE was significantly altered in patients with several skeletal, metabolic, and hematological disorders: reduced in congenital generalized lipodystrophy, achondroplasia (SADDAN), pseudoachondroplasia, and Paget disease of bone and elevated in alcaptonuria and sickle cell anemia. Our findings indicate that under appropriate culture conditions, CFE values may provide useful insights into bone/bone marrow pathophysiology.

Objective: Fibrous dysplasia (FD) is a skeletal disorder often associated with McCune-Albright syndrome, a rare multisystem disorder caused by GNAS1 gene mutation. FD frequently affects the craniofacial bones, including the maxilla and the mandible; nevertheless, its effects on dental tissues and the implications for dental care remain unclear. The aim of this study was to characterize the dental features associated with FD and the reaction of affected bones to routine dental therapy. Study design Thirty-two patients with FD underwent dental evaluation and endocrine testing as part of the diagnosis of FD/McCune-Albright syndrome. Any dental anomalies were recorded, and the associations between endocrinopathies and dental anomalies were analyzed statistically by means of the paired t test., Results: Eighty-four percent had FD in the maxilla and/or mandible; endocrine dysfunction; and/or renal phosphate wasting. The caries index scores were 2.9 (ages 4-17 years) and 9.6 (ages 18-50 years). Malocclusion (81%) and other prevalent dental anomalies (41%) included tooth rotation, oligodontia, and taurodontism. The expansion of the maxilla or mandible by FD did not distort the dental arch curvature, and routine dental therapies such as extractions, restorations, and orthodontic treatment did not exacerbate FD lesions., Conclusion: Maxillomandibular FD was associated with higher rates of caries and malocclusion than were present in healthy patients. Furthermore, patients with FD did not require special dental management and were able to undergo routine dental care without an exacerbation of FD lesions.