Contribution Of Bone Marrow-derived Cells Research Articles

Novel anti‐fibrotic modalities for liver fibrosis: Molecular targeting and regenerative medicine in fibrosis therapy

Based on the cellular and molecular mechanisms underlying hepatic fibrogenesis, several kinds of approaches have been proposed to treat liver fibrosis. Among a number of growth factors and cytokines that regulate collagen metabolism, transforming growth factor (TGF)-β is the most potent factor to accelerate liver fibrosis by activating hepatic stellate cells, stimulating collagen gene transcription, and suppressing matrix metalloproteinases expression. Thus, TGF-β as well as its intracellular mediators, Smad proteins, can be potential therapeutic targets for liver fibrosis. Constitutive phosphorylation and nuclear accumulation of Smad3 is the common feature of activated stellate cells. We have synthesized a novel small compound that inhibits Smad3-dependent collagen gene transcription by promoting nuclear import of a transcriptional repressor, YB-1. Another insight into anti-fibrotic strategies is the contribution of bone marrow-derived cells to the regression of liver fibrosis. Administration of granulocyte-colony stimulating factor enhanced the migration of bone marrow-derived cells into fibrotic liver tissue and accelerated the regression of experimental liver fibrosis. We have recently identified novel unknown factors expressed by bone marrow-derived cells that not only ameliorate liver fibrosis but also accelerate regeneration of fibrotic liver.

Bone Marrow-Derived Cells from Male Donors Do Not Contribute to the Endometrial Side Population of the Recipient

Accumulated evidence demonstrates the existence of bone marrow-derived cells origin in the endometria of women undergoing bone marrow transplantation (BMT). In these reports, cells of a bone marrow (BM) origin are able to differentiate into endometrial cells, although their contribution to endometrial regeneration is not yet clear. We have previously demonstrated the functional relevance of side population (SP) cells as the endogenous source of somatic stem cells (SSC) in the human endometrium. The present work aims to understand the presence and contribution of bone marrow-derived cells to the endometrium and the endometrial SP population of women who received BMT from male donors. Five female recipients with spontaneous or induced menstruations were selected and their endometrium was examined for the contribution of XY donor-derived cells using fluorescent in situ hybridization (FISH), telomapping and SP method investigation. We confirm the presence of XY donor-derived cells in the recipient endometrium ranging from 1.7% to 2.62%. We also identify 0.45–0.85% of the donor-derived cells in the epithelial compartment displaying CD9 marker, and 1.0–1.83% of the Vimentin-positive XY donor-derived cells in the stromal compartment. Although the percentage of endometrial SP cells decreased, possibly being due to chemotherapy applied to these patients, they were not formed by XY donor-derived cells, donor BM cells were not associated with the stem cell (SC) niches assessed by telomapping technique, and engraftment percentages were very low with no correlation between time from transplant and engraftment efficiency, suggesting random terminal differentiation. In conclusion, XY donor-derived cells of a BM origin may be considered a limited exogenous source of transdifferentiated endometrial cells rather than a cyclic source of BM donor-derived stem cells.

Bone Marrow Cells in Murine Colitis: Multi-Signal Analysis Confirms Pericryptal Myofibroblast Engraftment without Epithelial Involvement

BackgroundThe contribution of bone marrow-derived cells to epithelial tissues in the inflamed gut remains controversial. Recent reports have suggested that cell fusion between bone marrow-derived cells and the intestinal epithelium takes place in inflammatory conditions.MethodsIn attempts to confirm this, we have undertaken gender mis-matched bone marrow (BM) transplants from male Swiss Webster (SWR) mice to B and T cell-deficient female Rag2 KO mice which, 4 weeks later, were given 5% dextran sodium sulphate in drinking water to induce acute colitis. A further BM-treated group of animals with a graft versus host-like condition was also studied. We developed a new method to combine up to three brightfield or fluorescent lectin- or immuno-histochemical signals with fluorescent in situ hybridisation for the Y and X chromosomes to enable us unequivocally to identify BM-derived male cells which presented as different cell types in the gastrointestinal tract.Principal FindingsIn rolled preparations of whole intestines we scanned around 1.5 million crypts at many tissue levels. In no instance did we see a Y chromosome-positive cell in the epithelial compartment, which was not also CD45-positive. We saw no evidence of cell fusion, based on combined X and Y chromosome analysis. Levels of CD45-positive stromal and lymphoid cells and pericryptal myfibroblasts (positive for α-smooth muscle actin) increased with time up to a plateau, which resembled the level seen in untreated control grafted animals. We saw very few Y chromosome-positive endothelial cells in intestinal stromal vessels.ConclusionsWe conclude that whole BM transplantation does not result in intestinal epithelial engraftment in this model. Our new methods can usefully assist in multi-signal analyses of cell phenotypes following BM transplant and in models of chimaerism and regenerative medicine.

Preferential recruitment of bone marrow-derived cells to rat palatal wounds but not to skin wounds

ObjectiveTo investigate the contribution of bone marrow-derived cells to oral mucosa wounds and skin wounds. BackgroundBone marrow-derived cells are known to contribute to wound healing, and are able to differentiate in many different tissue-specific cell types. As wound healing in oral mucosa generally proceeds faster and with less scarring than in skin, we compared the bone marrow contribution in these two tissues. DesignBone marrow cells from GFP-transgenic rats were transplanted to irradiated wild-type rats. After recovery, 4-mm wounds were made in the mucoperiosteum or the skin. Two weeks later, wound tissue with adjacent normal tissue was stained for GFP-positive cells, myofibroblasts (a-smooth muscle actin), activated fibroblasts (HSP47), and myeloid cells (CD68). ResultsThe fraction of GFP-positive cells in unwounded skin (19%) was larger than in unwounded mucoperiosteum (0.7%). Upon wounding, the fraction of GFP-positive cells in mucoperiosteum increased (8.1%), whilst it was unchanged in skin. About 7% of the myofibroblasts in both wounds were GFP-positive, 10% of the activated fibroblasts, and 25% of the myeloid cells. ConclusionsThe results indicate that bone marrow-derived cells are preferentially recruited to wounded oral mucosa but not to wounded skin. This might be related to the larger healing potential of oral mucosa.

Bone Marrow Contributes Simultaneously to Different Neural Types in the Central Nervous System through Different Mechanisms of Plasticity

Many studies have reported the contribution of bone marrow-derived cells (BMDC) to the CNS, raising the possibility of using them as a new source to repair damaged brain tissue or restore neuronal function. This process has mainly been investigated in the cerebellum, in which a degenerative microenvironment has been suggested to be responsible for its modulation. The present study further analyzes the contribution of BMDC to different neural types in other adult brain areas, under both physiological and neurodegenerative conditions, together with the mechanisms of plasticity involved. We grafted genetically marked green fluorescent protein/Cre bone marrow in irradiated recipients: a) the PCD (Purkinje Cell Degeneration) mutant mice, suffering a degeneration of specific neuronal populations at different ages, and b) their corresponding healthy controls. These mice carried the conditional lacZ reporter gene to allow the identification of cell fusion events. Our results demonstrate that BMDC mainly generate microglial cells, although to a lesser extent a clear formation of neuronal types also exists. This neuronal recruitment was not increased by the neurodegenerative processes occurring in PCD mice, where BMDC did not contribute to rescuing the degenerated neuronal populations either. However, an increase in the number of bone marrow-derived microglia was found along the life span in both experimental groups. Six weeks after transplantation more bone marrow-derived microglial cells were observed in the olfactory bulb of the PCD mice compared to the control animals, where the degeneration of mitral cells was in process. In contrast, this difference was not observed in the cerebellum, where Purkinje cell degeneration had been completed. These findings demonstrated that the degree of neurodegenerative environment can foster the recruitment of neural elements derived from bone marrow, but also provide the first evidence that BMDC can contribute simultaneously to different encephalic areas through different mechanisms of plasticity: cell fusion for Purkinje cells and differentiation for olfactory bulb interneurons.

Abstract 3475: Tumor stage dependent contribution of bone marrow derived cells to tumor neo-vascularization

Abstract Introduction: The role of bone marrow derived cells (BMDC) in tumor neo-vascularization remains controversial. We have previously demonstrated that BMDC contribute to tumor neovascularization by differentiating into vascular support cells and not endothelial cell. In this study we focus on establishing the spatiotemporal role of BMDC in tumor neovascularisation, focusing on whether it is a tumor growth stage dependent process and more specifically examining the patterns of BMDC integration into tumor vasculature in response to radiation therapy (RTx). Methods: Animal Models: Bone marrow of NOD/SCID mice were stably reconstituted with BM harvested from green-fluorescent protein (GFP) transgenic mice. Intracranial (ic) xenografts were generated in intracranial window models (ICW) using a panel of glioma cell and breast cancer cells stably expressing mCherry. In-vivo imaging: Two-photon laser capture microscopy was used to obtain high-resolution real-time in-vivo longitudinal images of the tumor cells, tumor vasculature and tracing of the circulating GFP+BM cells. Mice were imaged 1d,2d,3d,7d,10d,14d,21d & 30d following cell implantation or RTx. Brain Tumor Analysis: Mice were sacrificed using perfusion fixation and brains collected for correlative immunohistochemical and Immunofluorscent confocal analysis. RTx: Using in-house designed x-ray micro-irradiator stereotactic radiation was delivered through ICW to ic-xenografts, treated with either 3×2Gy or 3×5Gy. Tumor+RTx was compared to RTx alone or tumor alone (n=15 each arm). Results: At early stages of tumor formation (<1wk) there is 90% integration of BMDC into the tumor vasculature, while to late stages of tumor growth (>2 wks) only 10% integration of BMDC is seen. At later stages of tumor growth (>2 wks) BMDC incorporation in the tumor vasculature is predominantly seen in the tumor periphery compared to the tumor centre, with the peripheral vessels demonstrating almost 100% integration of BMDC compared to the centre of the tumor where the vasculature have no integration of BMDC. Conclusions: Our results are the first to demonstrate that there is a specific tumor growth stage dependent contribution of BMDC to tumor neo-vascularization. At early stages of tumor growth neo-ascularization relies on host BMDC, while at later stages of tumor growth vascularization relies on branching of pre-existing vessels. A significant difference in extent of BMDC integration is noted between periphery versus the centre of the tumor, suggesting that the internal tumor micro-environment regulates neoascularization differently from the periphery. Intriguingly, this distinction is not seen with tumor neovascularization in recurrent tumors following RTx. These results have significant therapeutic implications and point to a need for scheduling of anti-angiogenic therapies according to tumor growth stage and timing post RTx. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3475. doi:10.1158/1538-7445.AM2011-3475

Differential Contribution of Dermal Resident and Bone Marrow–Derived Cells to Collagen Production during Wound Healing and Fibrogenesis in Mice

Recent studies show that bone marrow (BM)-derived cells migrating into a dermal wound promote healing by producing collagen type I. However, their contribution to the repair process has not been fully verified yet. It is also unclear whether BM-derived cells participate in dermal fibrogenesis. We have addressed these issues using transgenic mice that harbor tissue-specific enhancer/promoter sequences of α2(I) collagen gene linked to either enhanced green fluorescent protein (COL/EGFP) or the luciferase (COL/LUC) reporter gene. Following dermal excision or subcutaneous bleomycin administration, a large number of EGFP-positive collagen-producing cells appeared in the dermis of COL/EGFP reporter mice. When wild-type mice were transplanted with BM cells from transgenic COL/EGFP animals and subjected to dermal excision, no EGFP-positive BM-derived collagen-producing cells were detected throughout the repair process. Luciferase assays of dermal tissues from COL/LUC recipient mice also excluded collagen production by BM-derived cells during dermal excision healing. In contrast, a limited but significant number of CD45-positive collagen-producing cells migrated from BM following bleomycin injection. These results indicate that resident cells in the skin are the major source of de novo collagen deposition in both physiological and pathological conditions, whereas BM-derived cells participate, in part, in collagen production during dermal fibrogenesis.

腸管上皮再生における骨髄由来細胞の関与の検討

ハブ毒は強力な蛋白融解活性を有することが知られている．今回，ハブ毒静脈内投与による腸管絨毛傷害モデルマウスの作成を試みるとともに，このモデルを用いて腸管上皮再生における骨髄由来細胞の関与を検討した．各種濃度のハブ毒を C57BL/6 マウス尾静脈より投与し，用量―反応試験を行った結果，2.1 mg/kg ハブ毒投与によって，可逆性の腸管絨毛傷害を再現性よく惹起できることが明らかになった．次に GFP マウス骨髄細胞を移植したマウスに対し，ハブ毒を投与して腸管傷害を惹起し，再生絨毛上皮に存在する GFP 陽性細胞を組織学的に検討した．その結果， 再生上皮に存在する GFP 陽性細胞はハブ毒投与 3, 7 日後に有意な増加を認めた．骨髄由来で上皮細胞に分化したと考えられる (GFP 陽性CD45 陰性) 細胞もハブ毒投与後に一過性増加が認められたが，上皮細胞に占める割合は 1%以下であった．以上の結果より骨髄由来細胞は腸管絨毛傷害時の上皮再生過程に一部寄与する可能性が示唆された．

Human Barrett's Adenocarcinoma of the Esophagus, Associated Myofibroblasts, and Endothelium Can Arise from Bone Marrow-Derived Cells After Allogeneic Stem Cell Transplant

This study characterizes the contribution of bone marrow-derived cells (BMDCs) to Barrett's adenocarcinoma of the esophagus using a mouse surgical model of disease and human specimens. Transplantation of bone marrow expressing beta galactosidase into a wild-type mouse, followed by surgical esophagojejunostomy, allowed tracking of BMDCs into the surgical anastomosis and resulting Barrett's metaplasia. Human tissue from a male patient who had been transplanted with female bone marrow and later developed esophageal adenocarcinoma allowed us to tract donor-derived cells into the tumor. Using a combination of antibodies directed against beta-galactosidase (animal studies) and X/Y fluorescent in situ hybridization (FISH) (human studies), combined with specific lineage staining directed against epithelial, fibroblast, endothelial, and leukocyte markers, we show that bone marrow cells contribute to both the epithelial and stromal component of esophageal adenocarcinoma. These findings demonstrate that BMDCs can generate cancer-associated fibroblasts as well as contribute directly to epithelial cells in cancer of the esophagus.

Time-Course Analysis on the Differentiation of Bone Marrow-Derived Progenitor Cells Into Smooth Muscle Cells During Neointima Formation

Bone marrow-derived progenitor cells have been implicated to contribute to neointima formation, but the time course and extent of their accumulation and differentiation into vascular cells and, most importantly, the long-term contribution of bone marrow-derived progenitor cells to the vascular lesion remain undefined. Wire-induced injury of the femoral artery was performed on chimeric C57BL/6 mice transplanted with bone marrow from transgenic mice expressing enhanced green fluorescence protein, and vessels were harvested at 3 days, 1, 2, 3, 4, 6, and 16 weeks after dilatation (n=8 animals per time point). Using high-resolution microscopy, we unexpectedly found that the expression of smooth muscle cell or endothelial cell markers in enhanced green fluorescence protein positive cells was a very rare event. Indeed, most of the enhanced green fluorescence protein positive cells that accumulated during the acute inflammatory response were identified as monocytes/macrophages, and their number declined at later time points. In contrast, a substantial fraction of highly proliferative stem cell antigen-1 and CD34(+) but enhanced green fluorescence protein negative and thus locally derived cells were detected in the adventitia. These data provide evidence that the differentiation of bone marrow-derived progenitor cells into smooth muscle cell or endothelial cell lineages seems to be an exceedingly rare event. Moreover, the contribution of bone marrow-derived cells to the cellular compartment of the neointima is limited to a transient period of the inflammatory response.

Bone Marrow-Derived Cells Contribute to Fibrosis in the Chronically Failing Heart

Cardiac fibrosis contributes significantly to the phenotype of the chronically failing heart. It is not clear whether in this setting the fibrosis is contributed by native cardiac fibroblasts or alternatively by recruitment of cells arising from the bone marrow. We aimed to determine the contribution of bone marrow-derived cells to cardiac fibrosis in the failing heart and to investigate potentially contributing cytokines. Bone marrow-derived fibrocyte recruitment to the failing heart was studied in a transgenic (Mst1 mice) model of dilated cardiomyopathy. In conjunction, we examined the role of stromal-derived factor-1 (SDF-1), a key chemoattractant, by assessing myocardial expression and secretion by cardiomyocytes and in clinical samples. Bone marrow-derived cells were recruited in significantly greater numbers in Mst1 versus control mice (P < 0.001), contributing 17 +/- 4% of the total fibroblast load in heart failure. Patients with heart failure had higher plasma levels of SDF-1 than healthy control subjects (P < 0.01). We found that cardiomyocytes constitutively secrete SDF-1, which is significantly up-regulated by angiotensin II. SDF-1 was shown to increases cardiac fibroblast migration by 59% (P < 0.05). Taken together, our data suggest that recruitment of bone marrow-derived cells under the influence of factors, including SDF-1, may play an important role in the pathogenesis of cardiac fibrosis in heart failure.

Contribution of bone marrow-derived cells to the pro-inflammatory effects of protease-activated receptor-2 in colitis

ObjectiveOur aim was to determine the contribution of proteinase-activated receptor-2 (PAR2)-expressing bone marrow-derived cells on the development of colonic inflammation.MaterialsChimeric mice were generated by injecting bone marrow cells from wildtype (PAR2+/+) or PAR2 knockout mice (PAR2−/−) into irradiated PAR2+/+ or PAR2−/− mice. Treatments: Colitis was induced by giving 2.5% dextran sodium sulfate (DSS) solution for 7 days or by a single intracolonic administration of trinitrobenzene sulphonic acid (TNBS, 2 mg dissolved in 40% ethanol).MethodsSeven days after the induction of colitis, bowel thickness, inflammatory parameters [myeloperoxidase (MPO) activity, macroscopic/microscopic damage scores], and leukocyte trafficking (visualized via intravital microscopy) were assessed.ResultsTotal deficiency of PAR2 resulted in a marked reduction in severity of both TNBS and DSS induced colitis as assessed by MPO activity, macroscopic damage, bowel thickness, and leukocyte adherence. Colitis was attenuated in all chimeric lines in which there was loss of PAR2 in the host, non-bone marrow-derived tissue, independent of the status of PAR expression by bone marrow-derived cells. Interestingly, TNBS colitis was attenuated in PAR2+/+ chimeric mice with PAR2−/− derived bone marrow but these animals were not protected from DSS colitis.ConclusionsExpression of PAR2 by host-derived tissues plays a dominant role in regulating colonic inflammation. PAR2 expression by bone marrow-derived cells appears to play a role in TNBS colitis but not in DSS induced injury.Electronic supplementary materialThe online version of this article (doi:10.1007/s00011-010-0181-9) contains supplementary material, which is available to authorized users.

Bone marrow-derived stem cells in liver repair: 10 years down the line

Hematopoietic stem cells have potential in the field of regenerative medicine because of their capacity to form cells of different lineages. Bone marrow stem cells have been shown to contribute to parenchymal liver cell populations, and although this may not be functionally significant, it has sparked interest in the field of autologous stem cell infusion as a possible treatment for cirrhosis. In this review, we will examine the evidence for the contribution of bone marrow-derived cells to populations of liver cells and for the functional contribution of bone marrow-derived cells to both liver fibrosis and repair. The mechanisms by which cells are trafficked from the bone marrow to the liver are complex; the stromal derived factor-1/CXC receptor 4 axis is central to this process. There are limited data in liver injury, but we will examine findings from the bone marrow transplantation literature and discuss their relevance to liver disease. Stromal derived factor-1 also has a role in endogenous liver stem cell accumulation. Some groups have already started infusing autologous bone marrow cells into patients with cirrhosis. We will review these trials in the context of the basic science that we have discussed, and we will consider targets for investigation in the future.

Roles of Pancreatic Stellate Cells in Pancreatic Inflammation and Fibrosis

Over a decade, there is accumulating evidence that activated pancreatic stellate cells (PSCs) play a pivotal role in the development of pancreatic fibrosis. In response to pancreatic injury or inflammation, quiescent PSCs are transformed (activated) to myofibroblast-like cells, which express alpha-smooth muscle actin. Activated PSCs proliferate, migrate, produce extracellular matrix components, such as type I collagen, and express cytokines and chemokines. Recent studies have suggested novel roles of PSCs in local immune functions and angiogenesis in the pancreas. If the pancreatic inflammation and injury are sustained or repeated, PSC activation is perpetuated, leading to the development of pancreatic fibrosis. In this context, pancreatic fibrosis can be defined as pathologic changes of extracellular matrix composition in both quantity and quality, resulting from perpetuated activation of PSCs. Because PSCs are very similar to hepatic stellate cells, PSC research should develop in directions more relevant to the pathophysiology of the pancreas, for example, issues related to trypsin, non-oxidative alcohol metabolites, and pancreatic cancer. Indeed, in addition to their roles in chronic pancreatitis, it has been increasingly recognized that PSCs contribute to the progression of pancreatic cancer. Very recently, contribution of bone marrow-derived cells to PSCs was reported. Further elucidation of the roles of PSCs in pancreatic fibrosis should promote development of rational approaches for the treatment of chronic pancreatitis and pancreatic cancer.

Negligible Contribution of Bone Marrow-Derived Cells to Collagen Production During Hepatic Fibrogenesis in Mice

Recent studies have reported that bone marrow (BM)-derived cells migrating into fibrotic liver tissue exhibit a myofibroblast-like phenotype and may participate in the progression of liver fibrosis. However, their contribution to collagen production has not been fully verified yet. We revisited this issue by using 2 mechanistically distinct liver fibrosis models introduced into transgenic collagen reporter mice and their BM recipients. BM of wild-type mice was replaced by cells obtained from transgenic animals harboring tissue-specific enhancer/promoter sequences of alpha2(I) collagen gene (COL1A2) linked to enhanced green fluorescent protein (EGFP) or firefly luciferase (LUC) gene. Liver fibrosis was introduced into those mice by repeated carbon tetrachloride injections or ligation of the common bile duct. Activation of COL1A2 promoter was assessed by confocal microscopic examination detecting EGFP signals and luciferase assays of liver homogenates. The tissue-specific COL1A2 enhancer/promoter was activated in hepatic stellate cells following a single carbon tetrachloride injection or during primary culture on plastic. A large number of EGFP-positive collagen-expressing cells were observed in liver tissue of transgenic COL1A2/EGFP mice in both liver fibrosis models. In contrast, there were few EGFP-positive BM-derived collagen-producing cells detected in fibrotic liver tissue of COL1A2/EGFP recipients. Luciferase assays of liver tissues from COL1A2/LUC-recipient mice further indicated that BM-derived cells produced little collagen in response to fibrogenic stimuli. By using a specific and sensitive experimental system, which detects exclusively BM-derived collagen-producing cells, we conclude an unexpectedly limited role of BM-derived cells in collagen production during hepatic fibrogenesis.

Angiogenic Monocytes: Another Colorful Blow to Endothelial Progenitors

This Commentary provides perspective on a related article by Sun-Jin Kim and coworkers (Am J Pathol: 172 AJP08-0819), who assess the contribution of bone marrow-derived cells to tumor angiogenesis in a physiologic, non-myeloablative setting and conclude that the actual angiogenic cell type incorporated in the newly formed vessels is actually monocytes/macrophages.

Fluvastatin accelerates re-endothelialization impaired by local sirolimus treatment

Sirolimus-eluting stent reduces restenosis after percutaneous coronary intervention. However, accumulating evidence suggests that sirolimus potentially affects re-endothelialization, leading to late thrombosis. Statins have protective effects on endothelium. Recently, statins are reported to increase the number of circulating endothelial progenitor cells (EPCs) and accelerate re-endothelialization after vascular injury. Here, we tested the hypothesis that fluvastatin has beneficial effect on re-endothelialization after local sirolimus treatment. We performed wire-mediated vascular injury to both sides of femoral arteries of wild-type mice and bone marrow chimeric mice. Either sirolimus (100 μg) or DMSO was administered locally to the perivascular area of the injured arteries. All mice received either fluvastatin (5 mg/kg/day) or vehicle by gavage starting at one week before the surgery until sacrifice. At 4 weeks after the surgery, re-endothelialization of the sirolimus-treated artery was significantly less than that of DMSO-treated one in the vehicle-treated mice as determined by the percentage of CD31-positive area ( P < 0.05). Systemic administration of fluvastatin accelerated the re-endothelialization in the sirolimus-treated artery to the similar degree of that in the DMSO-treated artery ( P = NS). Contribution of bone marrow-derived cells to re-endothelialization was seldom observed in bone marrow chimeric mice regardless of fluvastatin administration. Fluvastatin significantly ameliorated proliferation (2.5-folds) and migration activities (2.3-folds) of mature endothelial cells impaired by sirolimus treatment ( P < 0.05, respectively). Fluvastatin increased endothelial nitric oxide synthase expression and decreased plasminogen activator inhibitor-1 expression in mature endothelial cell in the presence of sirolimus ( P < 0.05, respectively). Our findings suggest that fluvastatin has protective effects against impaired re-endothelialization after sirolimus treatment.

Human Gastrointestinal Neoplasia-Associated Myofibroblasts Can Develop from Bone Marrow-Derived Cells Following Allogeneic Stem Cell Transplantation

This study characterized the contribution of bone marrow-derived cells to human neoplasia and the perineoplastic stroma. The Australasian Bone Marrow Transplant Recipient Registry was used to identify solid organ neoplasia that developed in female recipients of male allogeneic stem cell transplants. Eighteen suitable cases were identified including several skin cancers, two gastric cancers, and one rectal adenoma. Light microscopy, fluorescence and chromogenic in situ hybridization, and immunohistochemistry were performed to determine the nature and origin of the neoplastic and stromal cells. In contrast to recent reports, donor-derived neoplastic cells were not detected. Bone marrow-derived neoplasia-associated myofibroblasts, however, were identified in the rectal adenoma and in a gastric cancer. Bone marrow-derived cells can generate myofibroblasts in the setting of human gastrointestinal neoplasia.

The Role of Stem Cell Factor and Granulocyte-Colony Stimulating Factor in Brain Repair during Chronic Stroke

Chronic stroke is a highly important but under-investigated scientific problem in neurologic research. We have reported earlier that stem cell factor (SCF) in combination with granulocyte-colony stimulating factor (G-CSF) treatment during chronic stroke improves functional outcomes. Here we have determined the contribution of bone marrow-derived cells in angiogenesis and neurogenesis, which are enhanced by SCF+G-CSF treatment during chronic stroke. Using bone marrow tracking, flow cytometry, 2-photon live brain imaging, and immunohistochemistry, we observed that the levels of circulating bone marrow stem cells (BMSCs) (CD34+/c-kit+) were significantly increased by SCF+G-CSF treatment. In addition, live brain imaging revealed that numerous bone marrow-derived cells migrate into the brain parenchyma in the treated mice. We also found that bone marrow-derived cells, bone marrow-derived endothelial cells, vascular density, and bone marrow-derived neurons were significantly augmented by SCF+G-CSF. It is interesting that, in addition to the increase in bone marrow-derived endothelial cells, the number of bone marrow-derived pericytes was reduced after SCF+G-CSF treatment during chronic stroke. These data suggest that SCF+G-CSF treatment can enhance repair of brain damage during chronic stroke by mobilizing BMSCs, and promoting the contribution of bone marrow-derived cells to angiogenesis and neurogenesis.

Bone marrow-derived cells and epithelial tumours: more than just an inflammatory relationship

Cancer-associated fibroblasts/myofibroblasts and inflammatory cells produce a vast array of growth factors, chemokines and extracellular matrix (ECM) components that facilitate cancer progression, invasion/metastasis and neovascularization. This review highlights some surprisingly novel mechanisms of this paracrine relationship. Mesenchymal stem/stromal cells (MSCs) are known for their tropism towards certain tumours, but now we find that cross-talk between tumours and MSCs leads to greater tumour motility and metastasis. Two closely related populations of immature myeloid cells, so-called 'cap cells' and myeloid-derived suppressor cells (MDSCs) also cross-talk with tumour cells, promoting invasion and metastasis through matrix metalloproteinase (MMP) secretion, as well as contributing to neovascularization and T-cell tolerance. The contribution of bone marrow-derived cells (BMDCs) to tumour neovascularization is controversial, but BMD--endothelial progenitor cells (EPCs)--are strongly implicated in the angiogenic switch in a mouse model. BMDCs are also credited with the creation of premetastatic niches to which metastatic cells adhere via integrins. There is no doubt that BMDCs are not simply bystanders in the tumour battleground. The mechanisms through which they aid tumour progression are numerous; effective treatments that combat BMDC-tumour cross-talk are surely on the way.