|  |  |  | | | | | TERMSC | | | | | | | | | | | | | | | | | | | Emerging therapeutic approaches for multipotent mesenchymal stromal cells. Curr Opin Hematol. 2010 Nov;17(6):505-13 Authors: Caimi PF, Reese J, Lee Z, Lazarus HM Multipotent mesenchymal stromal cells (MSCs) are rare cells resident in bone marrow and other organs capable of differentiating into mesodermal lineage tissues. MSCs possess immunomodulatory properties and have extensive capacity for ex-vivo expansion. Early clinical studies demonstrated safety and feasibility of infusing autologous MSCs and suggested a role in enhancing engraftment after hematopoietic cell transplant (HCT). Subsequent pilot studies using allogeneic MSCs showed safety but presented contradictory results regarding efficacy in treating graft-versus-host disease (GVHD). PMID: 20729733 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Osteogenesis and angiogenesis of tissue-engineered bone constructed by prevascularized β-tricalcium phosphate scaffold and mesenchymal stem cells. Biomaterials. 2010 Dec;31(36):9452-61 Authors: Wang L, Fan H, Zhang ZY, Lou AJ, Pei GX, Jiang S, Mu TW, Qin JJ, Chen SY, Jin D Although vascularized tissue-engineered bone grafts (TEBG) have been generated ectopically in several studies, the use of prevascularized TEBG for segmental bone defect repair are rarely reported. In current study, we investigated the efficacy of prevascularized TEBG for segmental defect repair. The segmental defects of 15 mm in length were created in the femurs of rabbits bilaterally. In treatment group, the osteotomy site of femur was implanted with prevascularized TEBG, which is generated by seeding mesenchymal stem cells (MSCs) into β-TCP scaffold, and prevascularization with the insertion of femoral vascular bundle into the side groove of scaffold; whereas in the control group, only MSC mediated scaffolds (TEBG) were implanted. The new bone formation and vascularization were investigated and furthermore, the expression of endogenous vascular endothelial growth factor (VEGF) which might express during defect healing was evaluated, as well. At 4, 8, and 12 weeks postoperatively, the treatment of prevascularized TEBG led to significantly higher volume of regenerated bone and larger amount of capillary infiltration compared to non-vascularized TEBG. The expression of VEGF in mRNA and protein levels increased with implantation time and peaked at 4 weeks postoperatively, followed by a slow decrease, however, treatment group expressed a significant higher level of VEGF than control group throughout the whole study. In conclusion, this study demonstrated that prevascularized TEBG by insertion of vascular bundle could significantly promote the new bone regeneration and vascularization compared to non-vascularized TEBG, which could be partially explained by the up-regulated expression of VEGF. PMID: 20869769 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | The discrimination of type I and type II collagen and the label-free imaging of engineered cartilage tissue. Biomaterials. 2010 Dec;31(36):9415-21 Authors: Su PJ, Chen WL, Li TH, Chou CK, Chen TH, Ho YY, Huang CH, Chang SJ, Huang YY, Lee HS, Dong CY Using excitation polarization-resolved second harmonic generation (SHG) microscopy, we measured SHG intensity as a function of the excitation polarization angle for type I and type II collagens. We determined the second order susceptibility (χ((2))) tensor ratios of type I and II collagens at each pixel, and displayed the results as images. We found that the χ((2)) tensor ratios can be used to distinguish the two types of collagen. In particular, we obtained χ(zzz)/χ(zxx) = 1.40 ± 0.04 and χ(xzx)/χ(zxx) = 0.53 ± 0.10 for type I collagen from rat tail tendon, and χ(zzz)/χ(zxx) = 1.14 ± 0.09 and χ(xzx)/χ(zxx) = 0.29 ± 0.11 for type II collagen from rat trachea cartilage. We also applied this methodology on the label-free imaging of engineered cartilage tissue which produces type I and II collagen simultaneously. By displaying the χ((2)) tensor ratios in the image format, the variation in the χ((2)) tensor ratios can be used as a contrast mechanism for distinguishing type I and II collagens. PMID: 20875682 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Eyes absent 1 (Eya1) is a critical coordinator of epithelial, mesenchymal and vascular morphogenesis in the mammalian lung. Dev Biol. 2011 Feb 1;350(1):112-26 Authors: El-Hashash AH, Al Alam D, Turcatel G, Bellusci S, Warburton D The proper level of proliferation and differentiation along the proximodistal axis is crucial for lung organogenesis. Elucidation of the factors that control these processes will therefore provide important insights into embryonic lung development and regeneration. Eya1 is a transcription factor/protein phosphatase that regulates cell lineage specification and proliferation. Yet its functions during lung development are unknown. In this paper we show that Eya1(-/-) lungs are severely hypoplastic with reduced epithelial branching and increased mesenchymal cellularity. Eya1 is expressed at the distal epithelial tips of branching tubules as well as in the surrounding distal mesenchyme. Eya1(-/-) lung epithelial cells show loss of progenitor cell markers with increased expression of differentiation markers and cell cycle exit. In addition, Eya1(-/-) embryos and newborn mice exhibit severe defects in the smooth muscle component of the bronchi and major pulmonary vessels with decreased Fgf10 expression. These defects lead to rupture of the major vessels and hemorrhage into the lungs after birth. Treatment of Eya1(-/-) epithelial explants in culture with recombinant Fgf10 stimulates epithelial branching. Since Shh expression and activity are abnormally increased in Eya1(-/-) lungs, we tested whether genetically lowering Shh activity could rescue the Eya1(-/-) lung phenotype. Indeed, genetic reduction of Shh partially rescues Eya1(-/-) lung defects while restoring Fgf10 expression. This study provides the first evidence that Eya1 regulates Shh signaling in embryonic lung, thus ensuring the proper level of proliferation and differentiation along the proximodistal axis of epithelial, mesenchymal and endothelial cells. These findings uncover novel functions for Eya1 as a critical upstream coordinator of Shh-Fgf10 signaling during embryonic lung development. We conclude, therefore, that Eya1 function is critical for proper coordination of lung epithelial, mesenchymal and vascular development. PMID: 21129374 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Long-term stability of cell micropatterns on poly((3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl)ammonium hydroxide)-patterned silicon oxide surfaces. Biomaterials. 2010 Dec;31(36):9565-74 Authors: Cho WK, Kong B, Park HJ, Kim J, Chegal W, Choi JS, Choi IS In this work, we compared the long-term stability and integrity of cell patterns on newly reported, zwitterionic poly((3-(methacryloylamino)propyl)dimethyl(3-sulfopropyl)ammonium hydroxide) (poly(MPDSAH)) films with those on widely used, poly(poly(ethylene glycol) methyl ether methacrylate) (poly(PEGMEMA)) ones. The micropatterns of both polymers were formed on a silicon oxide surface by a combination of micropattern generation of a photoresist, vapor deposition of a silane-based polymerization initiator, and surface-initiated, atom transfer radical polymerization (SI-ATRP) of each monomer, MPDSAH or PEGMEMA. The successful formation of the silane initiator SAMs, and poly(MPDSAH) and poly(PEGMEMA) micropatterns was confirmed by X-ray photoelectron spectroscopy (XPS) and imaging ellipsometry. Onto each substrate patterned with poly(MPDSAH) or poly(PEGMEMA), NIH 3T3 fibroblast cells were seeded, and the cell micropatterns were generated by the selective adhesion of cells on the cell-adhesive region of the patterned surfaces. The cell pattern formed on the poly(MPDSAH)-patterned surface was observed to have a superior ability of finely maintaining its original, line-shaped structure up to for 20 days, when compared with the cell pattern formed on the poly(PEGMEMA)-patterned surface. In order to verify the relationship between the integrity of the cell micropatterns and the stability of the underlying non-biofouling polymer layers, we also investigated the long-term stability of the polymer films themselves, immersed in the cell culture media, for one month, in the aid of ellipsometry, contact goniometry, and XPS. PMID: 21056465 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Decellularization and recellularization of whole livers. J Vis Exp. 2011;(48): Authors: Uygun BE, Price G, Saedi N, Izamis ML, Berendsen T, Yarmush M, Uygun K The liver is a complex organ which requires constant perfusion for delivery of nutrients and oxygen and removal of waste in order to survive(1). Efforts to recreate or mimic the liver microstructure with grounds up approach using tissue engineering and microfabrication techniques have not been successful so far due to this design challenge. In addition, synthetic biomaterials used to create scaffolds for liver tissue engineering applications have been limited in inducing tissue regeneration and repair in large part due to the lack of specific cell binding motifs that would induce the proper cell functions(2). Decellularized native tissues such blood vessels(3)and skin(4)on the other hand have found many applications in tissue engineering, and have provided a practical solution to some of the challenges. The advantage of decellularized native matrix is that it retains, to an extent, the original composition, and the microstructure, hence enhancing cell attachment and reorganization(5). In this work we describe the methods to perform perfusion-decellularization of the liver, such that an intact liver bioscaffold that retains the structure of major blood vessels is obtained. Further, we describe methods to recellularize these bioscaffolds with adult primary hepatocytes, creating a liver graft that is functional in vitro, and has the vessel access necessary for transplantation in vivo. PMID: 21339718 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Biocompatibility of adhesive complex coacervates modeled after the sandcastle glue of Phragmatopoma californica for craniofacial reconstruction. Biomaterials. 2010 Dec;31(36):9373-81 Authors: Winslow BD, Shao H, Stewart RJ, Tresco PA Craniofacial reconstruction would benefit from a degradable adhesive capable of holding bone fragments in three-dimensional alignment and gradually being replaced by new bone without loss of alignment or volume changes. Modeled after a natural adhesive secreted by the sandcastle worm, we studied the biocompatibility of adhesive complex coacervates in vitro and in vivo with two different rat calvarial models. We found that the adhesive was non-cytotoxic and supported the attachment, spreading, and migration of a commonly used osteoblastic cell line over the course of several days. In animal studies we found that the adhesive was capable of maintaining three-dimensional bone alignment in freely moving rats over a 12 week indwelling period. Histological evidence indicated that the adhesive was gradually resorbed and replaced by new bone that became lamellar across the defect without loss of alignment, changes in volume, or changes in the adjacent uninjured bone. The presence of inflammatory cells was consistent with what has been reported with other craniofacial fixation methods including metal plates, screws, tacks, calcium phosphate cements and cyanoacrylate adhesives. Collectively, the results suggest that the new bioadhesive formulation is degradable, osteoconductive and appears suitable for use in the reconstruction of craniofacial fractures. PMID: 20950851 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Derivation and characterization of human embryonic stem cell lines from the Chinese population. J Genet Genomics. 2011 Jan;38(1):13-20 Authors: Wu Z, Li H, Rao L, He L, Bao L, Liao J, Cui C, Zuo Z, Li Q, Dai H, Qian L, Tian Q, Xiao L, Tan X Human embryonic stem cells (hESCs) can self-renew indefinitely and differentiate into all cell types in the human body. Therefore, they are valuable in regenerative medicine, human developmental biology and drug discovery. A number of hESC lines have been derived from the Chinese population, but limited of them are available for research purposes. Here we report the derivation and characterization of two hESC lines derived from human blastocysts of Chinese origin. These hESCs express alkaline phosphatase and hESC-specific markers, including Oct4, Nanog, SSEA-3, SSEA-4, TRA-1-60 and TRA-1-81. They also have high levels of telomerase activity and normal karyotypes. These cells can form embryoid body in vitro and can be differentiated into all three germ layers in vivo by teratoma formation. The newly established hESCs will be distributed for research purposes. The availability of hESC lines from the Chinese population will facilitate studies on the differences in hESCs from different ethnic groups. PMID: 21338948 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Hematopoietic Stem Cell Homing to Injured Tissues. Stem Cell Rev. 2011 Feb 22; Authors: Kavanagh DP, Kalia N The use of stem cells is considered a promising therapy for tissue regeneration and repair, particularly for tissues injured through degeneration, ischemia and inflammation. Bone marrow (BM)-derived haematopoietic stem cells (HSCs) are rare populations of multipotent stem cells that have been identified as promising potential candidates for treating a broad range of conditions. Although research into the use of stem cells for regenerative medicine is on a steep upward slope, clinical success has not been as forthcoming. This has been primarily attributed to a lack of information on the basic biology of stem cells, which remains insufficient to justify clinical studies. In particular, while our knowledge on the molecular adhesive mechanisms and local environmental factors governing stem cell homing to BM is detailed, our understanding of the mechanisms utilized at injured sites is very limited. For instance, it is unclear whether mechanisms used at injured sites are location specific or whether this recruitment can be modulated for therapeutic purposes. In addition, it has recently been suggested that platelets may play an important role in stem cell recruitment to sites of injury. A better understanding of the mechanisms used by stem cells during tissue homing would allow us to develop strategies to improve recruitment of these rare cells. This review will focus on the status of our current understanding of stem cell homing to injured tissues, the role of platelets and directions for the future. PMID: 21340505 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Methods for making induced pluripotent stem cells: reprogramming à la carte. Nat Rev Genet. 2011 Feb 22; Authors: González F, Boué S, Belmonte JC Pluripotent stem-cell lines can be obtained through the reprogramming of somatic cells from different tissues and species by ectopic expression of defined factors. In theory, these cells - known as induced pluripotent stem cells (iPSCs) - are suitable for various purposes, including disease modelling, autologous cell therapy, drug or toxicity screening and basic research. Recent methodological improvements are increasing the ease and efficiency of reprogramming, and reducing the genomic modifications required to complete the process. However, depending on the downstream applications, certain technologies have advantages over others. Here, we provide a comprehensive overview of the existing reprogramming approaches with the aim of providing readers with a better understanding of the reprogramming process and a basis for selecting the most suitable method for basic or clinical applications. PMID: 21339765 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The autophagic tumor stroma model of cancer or "battery-operated tumor growth": A simple solution to the autophagy paradox. Cell Cycle. 2010 Nov;9(21):4297-306 Authors: Martinez-Outschoorn UE, Whitaker-Menezes D, Pavlides S, Chiavarina B, Bonuccelli G, Casey T, Tsirigos A, Migneco G, Witkiewicz A, Balliet R, Mercier I, Wang C, Flomenberg N, Howell A, Lin Z, Caro J, Pestell RG, Sotgia F, Lisanti MP The role of autophagy in tumorigenesis is controversial. Both autophagy inhibitors (chloroquine) and autophagy promoters (rapamycin) block tumorigenesis by unknown mechanism(s). This is called the "Autophagy Paradox". We have recently reported a simple solution to this paradox. We demonstrated that epithelial cancer cells use oxidative stress to induce autophagy in the tumor microenvironment. As a consequence, the autophagic tumor stroma generates recycled nutrients that can then be used as chemical building blocks by anabolic epithelial cancer cells. This model results in a net energy transfer from the tumor stroma to epithelial cancer cells (an energy imbalance), thereby promoting tumor growth. This net energy transfer is both unilateral and vectorial, from the tumor stroma to the epithelial cancer cells, representing a true host-parasite relationship. We have termed this new paradigm "The Autophagic Tumor Stroma Model of Cancer Cell Metabolism" or "Battery-Operated Tumor Growth". In this sense, autophagy in the tumor stroma serves as a "battery" to fuel tumor growth, progression and metastasis, independently of angiogenesis. Using this model, the systemic induction of autophagy will prevent epithelial cancer cells from using recycled nutrients, while the systemic inhibiton of autophagy will prevent stromal cells from producing recycled nutrients-both effectively "starving" cancer cells. We discuss the idea that tumor cells could become resistant to the systemic induction of autophagy, by the upregulation of natural endogenous autophagy inhibitors in cancer cells. Alternatively, tumor cells could also become resistant to the systemic induction of autophagy, by the genetic silencing/deletion of pro-autophagic molecules, such as Beclin1. If autophagy resistance develops in cancer cells, then the systemic inhibition of autophagy would provide a therapeutic solution to this type of drug resistance, as it would still target autophagy in the tumor stroma. As such, an anti-cancer therapy that combines the alternating use of both autophagy promoters and autophagy inhibitors would be expected to prevent the onset of drug resistance. We also discuss why anti-angiogenic therapy has been found to promote tumor recurrence, progression and metastasis. More specifically, anti-angiogenic therapy would induce autophagy in the tumor stroma via the induction of stromal hypoxia, thereby converting a non-aggressive tumor type to a "lethal" aggressive tumor phenotype. Thus, uncoupling the metabolic parasitic relationship between cancer cells and an autophagic tumor stroma may hold great promise for anti-cancer therapy. Finally, we believe that autophagy in the tumor stroma is the local microscopic counterpart of systemic wasting (cancer-associated cachexia), which is associated with advanced and metastatic cancers. Cachexia in cancer patients is not due to decreased energy intake, but instead involves an increased basal metabolic rate and increased energy expenditures, resulting in a negative energy balance. Importantly, when tumors were surgically excised, this increased metabolic rate returned to normal levels. This view of cachexia, resulting in energy transfer to the tumor, is consistent with our hypothesis. So, cancer-associated cachexia may start locally as stromal autophagy, and then spread systemically. As such, stromal autophagy may be the requisite precursor of systemic cancer-associated cachexia. PMID: 21051947 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | The isolation of cell derived extracellular matrix constructs using sacrificial open-cell foams. Biomaterials. 2010 Dec;31(36):9595-603 Authors: Wolchok JC, Tresco PA Extracellular matrix derived from human and animal tissues is being used to repair and reconstruct a variety of tissues clinically. The utility of such constructs is limited by the geometry, composition and constitutive properties of the tissue or organ from which the ECM is harvested. To address this limitation, we have developed an approach to isolate extracellular matrix in bulk from populations of living cells grown in culture on three-dimensional substrates. Human biopsy derived fibroblasts were seeded within open-cell foams and cultured in-vitro for periods up to three weeks, after which the synthetic component was removed by incubation in a water miscible solvent. After several wash steps and lyophilization, a white, lacy, multi-molecular construct was isolated. Tandem mass spectroscopy showed that it contained 22 extracellular matrix constituents, including such proteins and proteoglycans as collagen type I and type III, fibronectin, transforming growth factor beta, decorin and biglycan among others. On average 47 mg of construct was isolated for each gram of synthetic substrate initially seeded with cells. The biomaterial harvested from human tracheal fibroblasts had an elastic modulus (250 kPa) and a composition similar to that of human vocal fold tissue, and supported reseeding with human tracheal derived fibroblasts. An important finding was that the approach was useful in isolating ECM from a variety of cell lineages and developmental stages including skin fibroblasts, brain derived astrocytes and mesenchymal stem cells. The results, together with the archival literature, suggest that the approach can be used to produce a range of cell derived constructs with unique physical and chemical attributes for a variety of research and medical applications. PMID: 20950855 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Identification of adult nephron progenitors capable of kidney regeneration in zebrafish. Nature. 2011 Feb 3;470(7332):95-100 Authors: Diep CQ, Ma D, Deo RC, Holm TM, Naylor RW, Arora N, Wingert RA, Bollig F, Djordjevic G, Lichman B, Zhu H, Ikenaga T, Ono F, Englert C, Cowan CA, Hukriede NA, Handin RI, Davidson AJ Loss of kidney function underlies many renal diseases. Mammals can partly repair their nephrons (the functional units of the kidney), but cannot form new ones. By contrast, fish add nephrons throughout their lifespan and regenerate nephrons de novo after injury, providing a model for understanding how mammalian renal regeneration may be therapeutically activated. Here we trace the source of new nephrons in the adult zebrafish to small cellular aggregates containing nephron progenitors. Transplantation of single aggregates comprising 10-30 cells is sufficient to engraft adults and generate multiple nephrons. Serial transplantation experiments to test self-renewal revealed that nephron progenitors are long-lived and possess significant replicative potential, consistent with stem-cell activity. Transplantation of mixed nephron progenitors tagged with either green or red fluorescent proteins yielded some mosaic nephrons, indicating that multiple nephron progenitors contribute to a single nephron. Consistent with this, live imaging of nephron formation in transparent larvae showed that nephrogenic aggregates form by the coalescence of multiple cells and then differentiate into nephrons. Taken together, these data demonstrate that the zebrafish kidney probably contains self-renewing nephron stem/progenitor cells. The identification of these cells paves the way to isolating or engineering the equivalent cells in mammals and developing novel renal regenerative therapies. PMID: 21270795 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Translational systems biology of inflammation: potential applications to personalized medicine. Per Med. 2010 Sep 1;7(5):549-559 Authors: Mi Q, Li NY, Ziraldo C, Ghuma A, Mikheev M, Squires R, Okonkwo DO, Verdolini-Abbott K, Constantine G, An G, Vodovotz Y A central goal of industrialized nations is to provide personalized, preemptive and predictive medicine, while maintaining healthcare costs at a minimum. To do so, we must confront and gain an understanding of inflammation, a complex, nonlinear process central to many diseases that affect both industrialized and developing nations. Herein, we describe the work aimed at creating a rational, engineering-oriented and evidence-based synthesis of inflammation geared towards rapid clinical application. This comprehensive approach, which we call 'Translational Systems Biology', to date has been utilized for in silico studies of sepsis, trauma/hemorrhage/traumatic brain injury, acute liver failure and wound healing. This framework has now allowed us to suggest how to modulate acute inflammation in a rational and individually optimized fashion using engineering principles applied to a biohybrid device. We suggest that we are on the cusp of fulfilling the promise of in silico modeling for personalized medicine for inflammatory disease. PMID: 21339856 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Eugene Goldwasser (1922-2010). Nature. 2011 Feb 3;470(7332):40 Authors: Wojchowski D PMID: 21293362 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Human amniotic membrane as an alternative source of stem cells for regenerative medicine. Differentiation. 2011 Feb 19; Authors: Díaz-Prado S, Muiños-López E, Hermida-Gómez T, Cicione C, Rendal-Vázquez ME, Fuentes-Boquete I, de Toro FJ, Blanco FJ The human amniotic membrane (HAM) is a highly abundant and readily available tissue. This amniotic tissue has considerable advantageous characteristics to be considered as an attractive material in the field of regenerative medicine. It has low immunogenicity, anti-inflammatory properties and their cells can be isolated without the sacrifice of human embryos. Since it is discarded post-partum it may be useful for regenerative medicine and cell therapy. Amniotic membranes have already been used extensively as biologic dressings in ophthalmic, abdominal and plastic surgery. HAM contains two cell types, from different embryological origins, which display some characteristic properties of stem cells. Human amnion epithelial cells (hAECs) are derived from the embryonic ectoderm, while human amnion mesenchymal stromal cells (hAMSCs) are derived from the embryonic mesoderm. Both populations have similar immunophenotype and multipotential for in vitro differentiation into the major mesodermal lineages, however they differ in cell yield. Therefore, HAM has been proposed as a good candidate to be used in cell therapy or regenerative medicine to treat damaged or diseased tissues. PMID: 21339039 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Proteomics: a reality-check for putative stem cells. Circ Res. 2011 Feb 18;108(4):499-511 Authors: Prokopi M, Mayr M The concept of using stem cells for cardiovascular repair holds great potential, but uncertainties in preclinical experiments must be addressed before their therapeutic application. Contemporary proteomic techniques can help to characterize cell preparations more thoroughly and identify some of the potential causes that may lead to a high failure rate in clinical trials. The first part of this review discusses the broader application of proteomics to stem cell research by providing an overview of the main proteomic technologies and how they might help the translation of stem cell therapy. The second part focuses on the controversy about endothelial progenitor cells (EPCs) and raises cautionary flags for marker assignment and assessment of cell purity. A proteomics-led approach in early outgrowth EPCs has already raised the awareness that markers used to define their endothelial potential may arise from an uptake of platelet proteins. A platelet microparticle-related transfer of endothelial characteristics to mononuclear cells can result in a misinterpretation of the assay. The necessity to perform counterstaining for platelet markers in this setting is not fully appreciated. Similarly, the presence of platelets and platelet microparticles is not taken into consideration when functional improvements are directly attributed to EPCs, whereas saline solutions or plain medium serve as controls. Thus, proteomics shed new light on the caveats of a common stem cell assay in cardiovascular research, which might explain some of the inconsistencies in the field. PMID: 21335432 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Regenerated silk fibroin scaffold and infrapatellar adipose stromal vascular fraction as feeder layer: a new product for cartilage advanced therapy. Tissue Eng Part A. 2011 Feb 21; Authors: Chlapanidas T, Faragò S, Mingotto F, Crovato F, Tosca MC, Antonioli B, Bucco M, Lucconi G, Scalise A, Vigo D, Faustini M, Marazzi M, Torre ML Articular cartilage has limited repair and regeneration potential and the scarcity of treatment modalities has motivated attempts to engineer cartilage tissue constructs. The use of chondrocytes in cartilage tissue engineering has been restricted by the limited availability of these cells, their intrinsic tendency to lose their phenotype during the expansion, as well as the difficulties during the first cell adhesion to the scaffold. Aim of this work was to evaluate the intrarticular adipose stromal vascular fraction attachment on silk fibroin scaffold in order to promote chondrocytes adhesion and proliferation. Physicochemical characterization has demonstrated that 3D-organized silk fibroin scaffold is an ideal biopolymer for cartilage tissue engineering; it allows cell attachment, scaffold colonization and physically cell holding in the area that must be repaired; the use of adipose-derived stem cells is a promising strategy to promote adhesion and proliferation of chondrocytes to the scaffold as an autologous human feeder layer. PMID: 21338265 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Role of Altered Signal Transduction in Heterotopic Ossification and Fibrodysplasia Ossificans Progressiva. Curr Osteoporos Rep. 2011 Feb 22; Authors: Shore EM, Kaplan FS Heterotopic ossification is a pathologic condition in which bone tissue is formed outside of the skeleton, within soft tissues of the body. The extraskeletal bone that forms in these disorders is normal; the cellular mechanisms that direct cell fate decisions are dysregulated. Patients with fibrodysplasia ossificans progressiva (FOP), a rare human genetic disorder of extensive and progressive heterotopic ossification, have malformations of normal skeletal elements, identifying the causative gene mutation and its relevant signaling pathways as key regulators of skeletal development and of cell fate decisions by adult stem cells. The discovery that mildly activating mutations in ACVR1/ALK2, a bone morphogenetic protein (BMP) type I receptor, is the cause of FOP has provided opportunities to identify previously unknown functions for this receptor and for BMP signaling and to develop new diagnostic and therapeutic strategies for FOP and other more common forms of heterotopic ossification, as well as tissue engineering applications. PMID: 21340697 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Chondrogenesis of human mesenchymal stem cells mediated by the combination of SOX trio SOX5, 6, and 9 genes complexed with PEI-modified PLGA nanoparticles. Biomaterials. 2011 Feb 16; Authors: Park JS, Yang HN, Woo DG, Jeon SY, Do HJ, Lim HY, Kim JH, Park KH Target gene transfection for desired cell differentiation has recently become a major issue in stem cell therapy. For the safe and stable delivery of genes into human mesenchymal stem cells (hMSCs), we employed a non-viral gene carrier system such as polycataionic polymer, poly(ethyleneimine) (PEI), polyplexed with a combination of SOX5, 6, and 9 fused to green fluorescence protein (GFP), yellow fluorescence protein (YFP), or red fluorescence protein (RFP) coated onto PLGA nanoparticles. The transfection efficiency of PEI-modified PLGA nanoparticle gene carriers was then evaluated to examine the potential for chondrogenic differentiation by carrying the exogenous SOX trio (SOX5, 6, and 9) in hMSCs. Additionally, use of PEI-modified PLGA nanoparticle gene carriers was evaluated to investigate the potential for transfection efficiency to increase the potential ability of chondrogenesis when the trio genes (SOX5, 6, and 9) polyplexed with PEI were delivered into hMSCs. SOX trio complexed with PEI-modified PLGA nanoparticles led to a dramatic increase in the chondrogenesis of hMSCs in in vitro culture systems. For the PEI/GFP and PEI/SOX5, 6, and 9 genes complexed with PLGA nanoparticles, the expressions of GFP as reporter genes and SOX9 genes with PLGA nanoparticles showed 80% and 83% of gene transfection ratios into hMSCs two days after transfection, respectively. PMID: 21333351 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Adipose Derived Stem Cells in Functional Bone Tissue Engineering: Lessons from Bone Mechanobiology. Tissue Eng Part B Rev. 2011 Feb 21; Authors: Bodle JC, Hanson AD, Loboa E This review aims to highlight the current and significant work in the use of adipose-derived stem cells (ASC) in functional bone tissue engineering framed through the bone mechanobiology perspective. Over a century of work on the principles of bone mechanosensitivity is now being applied to our understanding of bone development. We are just beginning to harness that potential using stem cells in bone tissue engineering. ASC are the primary focus of this review due to their abundance and relative ease of accessibility for autologous procedures. This article outlines the current knowledge base in bone mechanobiology to investigate how the knowledge from this area has been applied to the various stem cell-based approaches to engineering bone tissue constructs. Specific emphasis is placed on the use of human ASC for this application. PMID: 21338267 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | In vivo ectopic chondrogenesis of BMSCs directed by mature chondrocytes. Biomaterials. 2010 Dec;31(36):9406-14 Authors: Liu X, Sun H, Yan D, Zhang L, Lv X, Liu T, Zhang W, Liu W, Cao Y, Zhou G In vivo niche plays an important role in determining the fate of exogenously implanted stem cells. Due to the lack of a proper chondrogenic niche, stable ectopic chondrogenesis of mesenchymal stem cells (MSCs) in subcutaneous environments remains a great challenge. The clinical application of MSC-regenerated cartilage in repairing defects in subcutaneous cartilage such as nasal or auricular cartilage is thus severely limited. The creation of a chondrogenic niche in subcutaneous environments is the key to solving this problem. The current study demonstrates that bone marrow stromal cells (BMSCs) could form cartilage-like tissue in a subcutaneous environment when co-transplanted with articular chondrocytes, indicating that chondrocytes could create a chondrogenic niche to direct chondrogenesis of BMSCs. Then, a series of in vitro co-culture models revealed that it was the secretion of soluble factors by chondrocytes but not cell-cell contact that provided the chondrogenic signals. The subsequent studies further demonstrated that multiple factors currently used for chondroinduction (including TGF-β1, IGF-1 and BMP-2) were present in the supernatant of chondrocyte-engineered constructs. Furthermore, all of these factors were required for initiating chondrogenic differentiation and fulfilled their roles in a coordinated way. These results suggest that paracrine signaling of soluble chondrogenic factors provided by chondrocytes was an important mechanism in directing the in vivo ectopic chondrogenesis of BMSCs. The multiple co-culture systems established in this study provide new methods for directing committed differentiation of stem cells as well as new in vitro models for studying differentiation mechanism of stem cells determined by a tissue-specific niche. PMID: 21056466 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Excitatory projection neuron subtypes control the distribution of local inhibitory interneurons in the cerebral cortex. Neuron. 2011 Feb 24;69(4):763-79 Authors: Lodato S, Rouaux C, Quast KB, Jantrachotechatchawan C, Studer M, Hensch TK, Arlotta P In the mammalian cerebral cortex, the developmental events governing the integration of excitatory projection neurons and inhibitory interneurons into balanced local circuitry are poorly understood. We report that different subtypes of projection neurons uniquely and differentially determine the laminar distribution of cortical interneurons. We find that in Fezf2(-/-) cortex, the exclusive absence of subcerebral projection neurons and their replacement by callosal projection neurons cause distinctly abnormal lamination of interneurons and altered GABAergic inhibition. In addition, experimental generation of either corticofugal neurons or callosal neurons below the cortex is sufficient to recruit cortical interneurons to these ectopic locations. Strikingly, the identity of the projection neurons generated, rather than strictly their birthdate, determines the specific types of interneurons recruited. These data demonstrate that in the neocortex individual populations of projection neurons cell-extrinsically control the laminar fate of interneurons and the assembly of local inhibitory circuitry. PMID: 21338885 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Chitosan scaffolds for osteochondral tissue regeneration. J Biomed Mater Res A. 2010 Dec 15;95(4):1132-41 Authors: Abarrategi A, Lópiz-Morales Y, Ramos V, Civantos A, López-Durán L, Marco F, López-Lacomba JL A variety of biomaterials have been introduced as potential substrates for cartilage repair. One such candidate is chitosan, which shares some characteristics with glycosaminoglycan and hyaluronic acid present in articular cartilage. Depending on chitosan source and preparation procedure, variations into its properties can be attained. Thus, the aim of this article is to study and select the most adequate chitosan properties for in vivo osteochondral tissue regeneration. In this work, chitosan molecular weight, deacetylation degree, and calcium content are tested as material variable properties. According to these properties, porous scaffolds were prepared, implanted in rabbit knee osteochondral defects, and evaluated 3 months after surgery. Results show in vitro a considerable influence of the material molecular weight on the scaffold structure. In vivo, different tissue responses were observed depending on the implanted chitosan properties. Some samples showed no material degradation, multiple adverse tissue responses, and no bone/cartilage tissue formation. Other samples showed no adverse responses and bone and cartilage tissue regeneration. The chitosan with intact mineral content (17.9 wt %), lowest molecular weight (11.49 KDa), and lowest deacetylation degree (83%) shows a well structured subchondral bone and noticeable cartilaginous tissue regeneration, being it the best one of those tested for osteochondral defect regeneration. PMID: 20878984 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Differentiation of Dental Pulp Stem Cells Into Islet Like Aggregates. J Dent Res. 2011 Feb 18; Authors: Govindasamy V, Ronald VS, Abdullah AN, Ganesan Nathan KR, Ab Aziz ZA, Abdullah M, Musa S, Abu Kasim NH, Bhonde RR The post-natal dental pulp tissue contains a population of multipotent mesenchymal progenitor cells known as dental pulp stromal/stem cells (DPSCs), with high proliferative potential for self-renewal. In this investigation, we explored the potential of DPSCs to differentiate into pancreatic cell lineage resembling islet-like cell aggregates (ICAs). We isolated, propagated, and characterized DPSCs and demonstrated that these could be differentiated into adipogenic, chondrogenic, and osteogenic lineage upon exposure to an appropriate cocktail of differentiating agents. Using a three-step protocol reported previously by our group, we succeeded in obtaining ICAs from DPSCs. The identity of ICAs was confirmed as islets by dithiozone-positive staining, as well as by expression of C-peptide, Pdx-1, Pax4, Pax6, Ngn3, and Isl-1. There were several-fold up-regulations of these transcription factors proportional to days of differentiation as compared with undifferentiated DPSCs. Day 10 ICAs released insulin and C-peptide in a glucose-dependent manner, exhibiting in vitro functionality. Our results demonstrated for the first time that DPSCs could be differentiated into pancreatic cell lineage and offer an unconventional and non-controversial source of human tissue that could be used for autologous stem cell therapy in diabetes. PMID: 21335539 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Design and Testing of a Pulsatile Conditioning System for Dynamic Endothelialization of Polyphenol-Stabilized Tissue Engineered Heart Valves. Cardiovasc Eng Technol. 2010 Jun;1(2):138-153 Authors: Sierad LN, Simionescu A, Albers C, Chen J, Maivelett J, Tedder ME, Liao J, Simionescu DT Heart valve tissue engineering requires biocompatible and hemocompatible scaffolds that undergo remodeling and repopulation, but that also withstand harsh mechanical forces immediately following implantation. We hypothesized that reversibly stabilized acellular porcine valves, seeded with endothelial cells and conditioned in pulsatile bioreactors would pave the way for next generations of tissue engineered heart valves (TEHVs). A novel valve conditioning system was first designed, manufactured and tested to adequately assess TEHVs. The bioreactor created proper closing and opening of valves and allowed for multiple mounting methods in sterile conditions. Porcine aortic heart valve roots were decellularized by chemical extractions and treated with penta-galloyl glucose (PGG) for stabilization. Properties of the novel scaffolds were evaluated by testing resistance to collagenase and elastase, biaxial mechanical analysis, and thermal denaturation profiles. Porcine aortic endothelial cells were seeded onto the leaflets and whole aortic roots were mounted within the dynamic pulsatile heart valve bioreactor system under physiologic pulmonary valve pressures and analyzed after 17 days for cell viability, morphology, and metabolic activity. Our tissue preparation methods effectively removed cells, including the potent α-Gal antigen, while leaving a well preserved extra-cellular matrix scaffold with adequate mechanical properties. PGG enhanced stabilization of extracellular matrix components but also showed the ability to be reversible. Engineered valve scaffolds encouraged attachment and survival of endothelial cells for extended periods and showed signs of widespread cell coverage after conditioning. Our novel approach shows promise toward development of sturdy and durable TEHVs capable of remodeling and cellular repopulation. PMID: 21340043 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Influence of stress on extracellular matrix and integrin biology. Oncogene. 2011 Feb 21; Authors: Jean C, Gravelle P, Fournie JJ, Laurent G Dynamic interactions between cells and extracellular matrix (ECM) through integrins influence most cellular functions. Normal cells, but even more, tumor cells are subjected to different forms of stress, including ischemia, radical oxygen species production, starvation, mechanical stress or genotoxic insults due to anti-cancer drugs or irradiation. In these situations, an adaptative cellular response occurs, integrating a complex network of intracellular signaling modules, which, depending on stress intensity, may result to either damage repair followed by complete restitution of cellular functions, or programmed cell death. Because of its implication in oncogenesis and anti-cancer therapy, cellular stress response has been thoroughly investigated. However, most of these studies have been performed in the context of isolated cells without taking into consideration that most cells are part of the tissue within which they interact with ECM through integrin. Few studies have described the influence of stress on cell-to-ECM interaction. However, one can speculate that, in these conditions, cells could functionally interact with protein microenvironment either to create positive interactions to survive (for example by facilitating protective pathways) or negative interaction to die (for example by facilitating detachment). In this review, we summarize the knowledge relative to the influence of different stress modalities on ECM remodeling, integrin expression and/or function modifications, and possible functional consequences, independently from the cellular model as these findings came from a large variety of cells (mesenchymal, endothelial, muscular, epithelial and glandular) and fields of application (cancer, vascular biology and tissue engineering). Most studies support the general notion that non-lethal stress favors ECM stiffness, integrin activation and enhanced survival. This field opens large perspectives not only in tumor biology but also in anti-cancer therapy by targeting one or several steps of the integrin-mediated signaling pathway, including integrin ligation, or activation of integrin-linked enzymes or integrin adaptors.Oncogene advance online publication, 21 February 2011; doi:10.1038/onc.2011.27. PMID: 21339741 [PubMed - as supplied by publisher] | | | | | | | | | |  | |  | |  |
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