Mobilization Of Bone Marrow-derived Cells Research Articles

Low-dose Cisplatin Induces Tumor Growth via Mobilization of Proangiogenic Bone Marrow-derived Cells in Mouse Models.

It is generally accepted that low-dose metronomic (LDM) chemotherapy mostly exerts its antitumor effects by inhibiting tumor angiogenesis. However, there is some evidence that LDM chemotherapy subsequently promotes tumor angiogenesis under certain regimens in animal models. The mechanisms responsible for these contradictory results are unclear. Cisplatin (CDDP) was intraperitoneally administered to tumor-bearing mice at doses of 0.05-3 mg/kg every other day. The effects of LDM chemotherapy with CDDP on tumor growth and angiogenesis were observed. To determine the involved mechanisms, we analyzed the expression of vascular basement membrane proteins, transcription of angiogenesis-related genes in tumor tissues, and mobilization of proangiogenic bone marrow-derived cells (BMDCs) in circulating blood. The mean tumor weight with the 3 mg/kg q.o.d. regimen CDDP was significantly lower (by 57.3%) in the CDDP than in the control group. However, the tumor weight was 52.1% higher for the 0.19 mg/kg q.o.d. regimen in the CDDP group, which could be antagonized using 30 mg/kg all-trans retinoic acid. For the 0.19 mg/kg q.o.d., more tumor vascular structures were observed in the CDDP than in the control group (47.9±5.0 vs. 22.3±0.8, p<0.001). The mobilization of VEGFR2+ BMDCs and the mRNA expression of the proangiogenic genes MMP9, VEGFR1, VEGFR2 and VE-cadherin were increased in the 0.19 mg/kg regimen. These results indicate that metronomic CDDP promoted tumor angiogenesis and tumor growth via increased mobilization of proangiogenic BMDCs at certain low doses. This implies a potential therapeutic risk from an inappropriate LDM chemotherapy dosage and suggests that optimizing the LDM chemotherapy regimen is urgently needed.

Induction of Skin Allograft Chimerism by Pharmacological Mobilization of Endogenous Bone Marrow-Derived Stem Cells.

Skin substitutes including allografts remain a standard therapeutic approach to promote healing of both acute and chronic large wounds. However, none have resulted in the regrowth of lost and damaged tissues and scarless wound healing. Here, we demonstrate skin allograft chimerism and repair through the mobilization of endogenous bone marrow-derived stem and immune cells in rats and swine. We show that pharmacological mobilization of bone marrow stem cells and immune cells into the circulation promotes host repopulation of skin allografts and restoration of the skin's normal architecture without scarring and minimal contracture. When skin allografts from DA rats are transplanted into GFP transgenic Lewis recipients with a combination of AMD3100 and low-dose FK506 (AF) therapy, host-derived GFP-positive cells repopulate and/or regenerate cellular components of skin grafts including epidermis and hair follicles and the grafts become donor-host chimeric skin. Using AF combination therapy, burn wounds with skin allografts were healed by newly regenerated chimeric skin with epidermal appendages and pigmentation and without contracture in swine.

Healing Effect of Subcutaneous Administration of Granulocyte Colony-Stimulating Factor on Acute Rotator Cuff Injury in a Rat Model.

Granulocyte colony-stimulating factor (G-CSF) is a cytokine that mobilizes bone marrow-derived cells (BMDCs) to peripheral blood and has been clinically used to treat neutropenia. Previously, we reported that BMDCs migrated into the rotator cuff repair site via peripheral blood in the healing process. However, techniques to accelerate the healing process using the peripheral blood pathway have not been established. We evaluated whether G-CSF has a noteworthy effect on improving rotator cuff healing by enhancing the influx of BMDCs into the peripheral blood. We used Sprague-Dawley rats and chimeric rats, selectively expressing green fluorescent protein (GFP) in BMDCs. Their bilateral supraspinatus tendons were resected and sutured to the greater tuberosity of the humerus using the Masson-Allen technique, and G-CSF was subcutaneously injected for 5 days after surgery. Several GFP-positive cells were observed around the enthesis in the G-CSF-treated group compared with that in the Control group. Histological analysis revealed that the tendon-to-bone maturing scores and the Safranin O-stained cartilaginous areas were significantly higher in G-CSF-injected rats than in the control rats at weeks 4 and 8 after surgery. Consistently, the ultimate force to failure in the G-CSF-treated group significantly increased compared with the Control group at weeks 4 and 8 after surgery. These results suggest that BMDCs mobilized into the peripheral blood after G-CSF administration migrated to the rotator cuff repair area and effectively enhanced rotator cuff healing by promoting tenocyte and cartilage matrix production. In conclusion, the BMDC mobilization technique by G-CSF treatment via peripheral blood will provide a potential therapeutic approach for rotator cuff healing with clinically relevant applications. Impact statement As the retear rate following rotator cuff repair is high, new methods to aid its healing are required. Granulocyte colony-stimulating factor (G-CSF) has been used clinically and may represent a novel approach to treating rotator cuff tear. Herein, using a rat model, we elucidate the kinetics of bone marrow-derived mesenchymal stem cells at the repair site following G-CSF administration and describe the underlying mechanism by which G-CSF can help promote the repair of the rotator cuff.

Compression Bioreactor-Based Mechanical Loading Induces Mobilization of Human Bone Marrow-Derived Mesenchymal Stromal Cells into Collagen Scaffolds In Vitro.

Articular cartilage (AC) is an avascular tissue composed of scattered chondrocytes embedded in a dense extracellular matrix, in which nourishment takes place via the synovial fluid at the surface. AC has a limited intrinsic healing capacity, and thus mainly surgical techniques have been used to relieve pain and improve function. Approaches to promote regeneration remain challenging. The microfracture (MF) approach targets the bone marrow (BM) as a source of factors and progenitor cells to heal chondral defects in situ by opening small holes in the subchondral bone. However, the original function of AC is not obtained yet. We hypothesize that mechanical stimulation can mobilize mesenchymal stromal cells (MSCs) from BM reservoirs upon MF of the subchondral bone. Thus, the aim of this study was to compare the counts of mobilized human BM-MSCs (hBM-MSCs) in alginate-laminin (alginate-Ln) or collagen-I (col-I) scaffolds upon intermittent mechanical loading. The mechanical set up within an established bioreactor consisted of 10% strain, 0.3 Hz, breaks of 10 s every 180 cycles for 24 h. Contrary to previous findings using porcine MSCs, no significant cell count was found for hBM-MSCs into alginate-Ln scaffolds upon mechanical stimulation (8 ± 5 viable cells/mm3 for loaded and 4 ± 2 viable cells/mm3 for unloaded alginate-Ln scaffolds). However, intermittent mechanical stimulation induced the mobilization of hBM-MSCs into col-I scaffolds 10-fold compared to the unloaded col-I controls (245 ± 42 viable cells/mm3 vs. 22 ± 6 viable cells/mm3, respectively; p-value < 0.0001). Cells that mobilized into the scaffolds by mechanical loading did not show morphological changes. This study confirmed that hBM-MSCs can be mobilized in vitro from a reservoir toward col-I but not alginate-Ln scaffolds upon intermittent mechanical loading, against gravity.

Integrin α5β1 promotes BMCs mobilization and differentiation to exacerbate choroidal neovascularization

Choroidal neovascularization (CNV) is an acknowledged pathogenic mechanism of various ocular diseases, and in situ cells and mobilized bone marrow-derived cells (BMCs) are thought to participate in this process. We aimed to evaluate the roles of integrin α5 in BMCs and vascular endothelial cells (VECs) in the CNV process mediated by SDF-1/CXCR4 signaling. Adult wild-type mice were engrafted with whole BMCs obtained from GFP transgenic mice and then laser injured to induce CNV. BMCs and RF/6A cells were cultured to discover the mechanism of CNV in vitro. BMCs were mobilized to CNV areas, which expressed elevated SDF-1 and CXCR4. When SDF-1 was intravitreally injected, the number of BMCs was profoundly increased. In the SDF-1-treated group, the levels of integrin α5 expressed on BMCs and VECs were significantly higher than those on the cells in the control group. SDF-1 significantly increased the expression and positive ratio of integrin α5, which was involved in the recruitment and differentiation of BMCs into BMC-derived VECs, and these effects were suppressed by the CXCR4 inhibitor AMD3100. The PI3K/AKT pathway rather than the ERK pathway mediated SDF-1/CXCR4 induction of integrin α5. Integrin α5 suppression efficiently prevented the production of TGF-β and bFGF but not VEGF. Inhibiting the SDF-1/CXCR4-PI3K/AKT-integrin α5 axis reduced CNV severity. Integrin α5 participates in BMC recruitment and differentiation in SDF-1/CXCR4-induced CNV and inhibition of this pathway may be a new approach to inhibit CNV.

Bone marrow-derived cell mobilization with suppression of CXCR4 mediated by exosomes carrying myocardial microRNAs for repair of the infarcted heart

As the capacities of proliferation and self-healing of cardiomyocytes in adults are limited, treatment of ischemic myocardium after acute myocardial infarction (AMI) led to a trend of investigations and research into human embryonic stem cells/induced pluripotent stem cells, cardiac stem/progenitor cells, bone marrow (BM)-derived cells including mesenchymal stem cells, and endothelial progenitor cells to promote cardiac neovascularization and repair of the ischemic injury to rescue the ischemic myocardium and function of the heart (1-3).

Differential expression profiles of the transcriptome in bone marrow-derived cells in lung cancer revealed by next generation sequencing and bioinformatics.

A pre-metastatic niche (PMN) facilitates cancer metastasis through mobilization and recruitment of bone marrow-derived cells (BMDCs) and associated factors. In bone marrow, hematogenous cells, including osteoclasts, macrophages and lymphocytes, and mesenchymal cells, including mesenchymal stem cells, osteoblasts and adipocytes, are involved in PMN formation. Patients with lung cancer and metastasis have a poor prognosis and shortened median survival time. Bone marrow has been considered fertile ground for dormant and proliferating tumor cells, and mobilizing and recruiting BMDCs and immune cells can establish a PMN. However, the role of BMDCs in PMN formation is not yet fully understood. The present study aimed to investigate the association between BMDCs and PMN in bone marrow tissue samples. The results demonstrated that bone marrow served an important role in lung cancer progression and that eight pathways were potentially involved, including ‘T-cell receptor signaling pathway’, ‘osteoclast differentiation’, ‘MAPK signaling pathway’, ‘VEGF signaling pathway’, ‘leukocyte transendothelial migration’, ‘signaling pathways regulating the pluripotency of stem cells’, ‘oxytocin signaling pathway’ and ‘cell adhesion molecules (CAMs)’. In addition, the present study investigated the role of BMDCs in facilitating lung cancer metastasis. In conclusion, the results from the present study suggested that molecular alterations in gene expression may provide a novel signature in lung cancer, which may aid in the development of novel diagnostic and therapeutic strategies for patients with lung cancer and bone metastasis.

Estrogen enhances tumor growth and angiogenesis indirectly via mediation of bone marrow‑derived cells as well as directly through stimulation of tumor and endothelial cells.

Estradiol (E2) is a prime culprit for enhancing the progression of female hormone‑related cancers. Bone marrow‑derived cells (BMDCs) have been found to play a pivotal role in tumor growth. Estrogen receptors (ERs) are also found on certain subtypes of BMDCs, in addition to endothelial cells (ECs) and certain tumor cells. However, the role of BMDCs in E2‑induced tumor biology is still unclear. Thus, the effects of E2 on ER‑negative 4T1 breast cancer growth, the mobilization and recruitment of BMDCs, and interactions among BMDCs, ECs, and 4T1 cells were investigated. The results showed that E2 potentiated 4T1 tumor growth and angiogenesis in mice subjected to sham operation, ovariectomy (OVX), or OVX and E2 replacement treatment. E2 supplementation in mice with OVX upregulated the transcription of stromal cell‑derived factor‑1 (SDF‑1) mRNA in tumor tissues and enhanced the recruitment of BMDCs into tumor tissues invivo. E2 deficiency significantly decreased proangiogenic CXCR4+, β3+, Sca‑1+ and CXCR4+β3+ BMDCs circulating in the peripheral blood. Cell‑based system analyses showed that E2 augmented the transcription of β3 mRNA in ECs, increased the adhesion of BMDCs to ECs. In addition, E2 enhanced the BMDC‑induced EC proliferation and migration, the BMDC‑induced 4T1 proliferation and the 4T1‑stimulated EC proliferation in addition to enhancing the proliferation of tumor cells and the migration of ECs invitro. Therefore, E2 enhanced the growth of breast tumors by stimulating tumor cells and ECs directly, as well as by increasing proangiogenic BMDC mobilization and recruitment leading to augmentation of the tumor and EC functions indirectly by cell proliferation assay. These findings reveal a separate mechanism via which E2 promotes the growth of female hormone‑dependent tumors, which may be useful in explorations of new therapies for related cancers.

Abstract 2059: Alcohol enhances estrogen-responsive breast cancer neovascularization

Abstract The pleiotropic effects of estrogen in breast cancer development have been observed at both the initiation and progression phases. Interestingly, alcohol, as a dietary component, has been observed to possess estrogenic activity, but the synergistic interaction between alcohol and estrogen and its cellular targets remains undefined. Our previous study identified neovascularization as a cellular target of estrogen that was mediated by the mobilization of bone marrow-derived endothelial progenitor cells (BM-EPCs) and their subsequent incorporation within the tumor mass. The present study was undertaken to define the synergistic interaction between estrogen and alcohol using a cell culture model. To examine the effects of both estrogen and alcohol on breast cancer progression, we developed an in vitro model using the murine mammary tumor cell line, TG1-1, and the murine endothelial cell line, SVEC4-10. Neovascularization was assayed by the tubulogenesis and scratch wound assays as well as quantitating the expression of various provasculogenic markers. Conditioned media, generated by culturing the murine mammary cancer cell line, TG1-1, in estrogen and ethanol, was observed to enhance tubule formation and migration of the murine endothelial cell line, SVEC4-10. In addition, the TG1-1 conditioned media enhanced the prosurvival MAP kinase-signaling pathway in SVEC4-10 cells. Presumably, the observed enhancement of both endothelial cell tubulogenesis and migration is in part attributed to provasculogenic proteins secreted by TG1-1 cells. In order to address this, Western blot analysis using TG1-1 cell lysates indicated an increase in VEGF, MMP-9, and eNOS expression in presence of alcohol and estrogen. As a whole, our data suggest that both estrogen and alcohol function to enhance expression of key provasculogenic molecules in breast cancer cells, which in turn modulates the morphologic, migratory, and survival properties of endothelial cells. Citation Format: Natalie C. Cruz, Rachana Maniyar, Robert Suriano. Alcohol enhances estrogen-responsive breast cancer neovascularization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2059.

Platelet-derived chemokines in inflammation and atherosclerosis

Platelets are inflammatory anuclear cells with a well-established role in the development and manifestation of atherosclerosis. Activated platelets secrete a plethora of chemokines including CXCL4 or platelet factor 4 (PF4), CCL5, CXCL12 or stromal cell derived factor-1α (SDF-1α), CXCL16 and others, which initiate or promote local inflammatory processes at sites of vascular injury. These processes are mainly mediated by the recruitment of circulating haematopoietic stem cells, neutrophils, monocytes or lymphocytes on vascular wall. Under acute ischemic conditions platelet-derived chemokines may promote the mobilization of bone marrow-derived progenitor cells and their homing at lesion sites. This review focuses on the role of platelet-derived chemokines in inflammation and atherosclerosis. Further, we discuss the clinical value of plasma levels of chemokines in the prognosis of atherosclerotic heart disease.

Increased Mobilization of CD45+CD34+VLA-4+ Cells in Acute Viral Myocarditis Induced by Coxsackievirus B3

Objectives: Bone marrow-derived cells (BMCs) have recently been identified to play a vital role in repairing damaged myocardium; however, it is not known whether or not mobilization of BMCs is involved in the pathogenesis of acute viral myocarditis (VMC). Thus, we analyzed the expression of CD45+CD34+VLA-4+ cells and vascular cell adhesion protein-1 (VCAM-1) in a murine model of acute VMC. Methods: Male BALB/c mice were intraperitoneally infected with coxsackievirus B3 to establish acute VMC. The frequency of CD45+CD34+VLA-4+ cells in the heart, peripheral blood, and bone marrow was examined by flow cytometry 3, 7, 14, and 28 days after injection. Cardiac VCAM-1 and pathology scores were determined by immunohistochemistry, and myocardial VCAM-1, IL-1β, and TNF-α were analyzed by RT-PCR and Western blot. Results: In mice with acute VMC, the CD45+CD34+VLA-4+ cell population in the heart was significantly increased by day 7 and then decreased; in contrast, the CD45+CD34+VLA-4+ cell population decreased in the bone marrow and peripheral blood by day 3 and then increased. High expression of VCAM-1 was detected in the heart in parallel with CD45+CD34+VLA-4+ cell expression. Conclusions: In mice with acute VMC, VCAM-1-induced CD45+CD34+VLA-4+ cell mobilization into the injured heart is involved in the repair of injured myocardium.

Therapeutic implications of granulocyte colony stimulating factor in patients with acute-on-chronic liver failure: increased survival and containment of liver damage.

Mobilization of bone marrow-derived stem cells by granulocyte colony stimulating factor (G-CSF) supports hepatic regeneration and may augment clinical improvement in patients with acute-on-chronic liver failure (ACLF). The aim of this study is to assess the impact of G-CSF on complications and transplant-free survival in patients with ACLF. Thirty-two patients with ACLF defined by Asian Pacific Association for the Study of the Liver (APASL) criteria were openly randomized to control (groupA) or intervention (groupB) receiving G-CSF (5μg/kg/day, for 6 consecutive days) in addition to standard medical therapy with antiviral drugs. The patients were followed for 90days. Simultaneous use of G-CSF and antiviral drugs in hepatitisB virus (HBV) ACLF significantly improved survival over antiviral drugs alone. Incidence of hepatorenal syndrome and hyponatremia were reduced due to use of G-CSF. Baseline parameters of the two groups of patients were comparable. Child-Turcotte-Pugh (CTP) and Model for End-Stage Liver Disease (MELD), disease severity scores improved in patients treated with G-CSF, with significant difference only for the CTP score at 90days follow-up. In addition, mean white blood cell (WBC) count at day15 was significantly higher in G-CSF group in absence of infection compared with control group. G-CSF therapy improved survival and clinical recovery in HBV-ACLF. G-CSF therapy also prevented renal failure and hyponatremia. We strongly recommend use of G-CSF therapy in addition to standard medical therapy.

Transforming growth factor β induces bone marrow mesenchymal stem cell migration via noncanonical signals and N-cadherin.

Transforming growth factor-beta (TGF-β) induces the migration and mobilization of bone marrow-derived mesenchymal stem cells (BM-MSCs) to maintain bone homeostasis during bone remodeling and facilitate the repair of peripheral tissues. Although many studies have reported the mechanisms through which TGF-β mediates the migration of various types of cells, including cancer cells, the intrinsic cellular mechanisms underlying cellular migration, and mobilization of BM-MSCs mediated by TGF-β are unclear. In this study, we showed that TGF-β activated noncanonical signaling molecules, such as Akt, extracellular signal-regulated kinase 1/2 (ERK1/2), focal adhesion kinase (FAK), and p38, via TGF-β type I receptor in human BM-MSCs and murine BM-MSC-like ST2 cells. Inhibition of Rac1 by NSC23766 and Src by PP2 resulted in impaired TGF-β-mediated migration. These results suggested that the Smad-independent, noncanonical signals activated by TGF-β were necessary for migration. We also showed that N-cadherin-dependent intercellular interactions were required for TGF-β-mediated migration using functional inhibition of N-cadherin with EDTA treatment and a neutralizing antibody (GC-4 antibody) or siRNA-mediated knockdown of N-cadherin. However, N-cadherin knockdown did not affect the global activation of noncanonical signals in response to TGF-β. Therefore, these results suggested that the migration of BM-MSCs in response to TGF-β was mediated through N-cadherin and noncanonical TGF-β signals.

Invited commentary

The pathologic impairment of wound healing in ischemic and diabetic conditions could be normalized by poly-ADP-ribose polymerase (PARP) inhibition. Dr Zhou showed that PARP inhibition enhances neovascularization, including angiogenesis and endothelial progenitor cell mobilization. These studies suggest that PARP inhibition may represent a promising therapeutic strategy for wound healing and wound repair. However, these exciting studies raise some important questions. First of all, it would be interesting to determine whether the topical route of administration of PARP inhibitors would have similar improvement in wound healing as systemic delivery. Topical PARP inhibition treatment probably may not affect the bone marrow-derived endothelial progenitor cell mobilization and homing into the wound beds because of absence of or not enough PARP inhibitors in the circulation. Therefore, it will tell us the contribution of local angiogenesis and vasculogenesis in ischemic and diabetic wound healing by PARP inhibition. Second, it seems that there are conflicting results on regulation of angiogenesis by PARP in other pathologic conditions, such as cancer and retinal angiogenesis.1Tentori L. Lacal P.M. Muzi A. Dorio A.S. Leonetti C. Scarsella M. et al.Poly(ADP-ribose) polymerase (PARP) inhibition or PARP-1 gene deletion reduces angiogenesis.Eur J Cancer. 2007; 43: 2124-2133Abstract Full Text Full Text PDF PubMed Scopus (119) Google Scholar, 2Mao H. Lockyer P. Townley-Tilson W.H. Xie L. Pi X. LRP1 regulates retinal angiogenesis by inhibiting PARP-1 activity and endothelial cell proliferation.Arterioscler Thromb Vasc Biol. 2016; 36: 350-360Crossref PubMed Scopus (30) Google Scholar PARP inhibition was demonstrated to reduce angiogenesis by decreasing both growth factor expression and cell proliferation. Further studies are needed to understand the molecular and cellular mechanisms of how PARP regulates angiogenesis in different contexts. In addition, the process of wound healing is complicated and involves multiple cell types, including endothelial cells, epithelial cells and fibroblasts, monocytes, and bone marrow progenitor cells, as well as multiple cell behaviors, such as cell proliferation, migration, and adhesion. Cell-specific and genetic modification of PARP in animals will help us to better understand the role and mechanisms of PARP in the pathologic impairment of wound healing. Poly-ADP-ribose polymerase inhibition enhances ischemic and diabetic wound healing by promoting angiogenesisJournal of Vascular SurgeryVol. 65Issue 4PreviewChronic nonhealing wounds are a major health problem for patients in the United States and worldwide. Diabetes and ischemia are two major risk factors behind impaired healing of chronic lower extremity wounds. Poly-ADP-ribose polymerase (PARP) is found to be overactivated with both ischemic and diabetic conditions. This study seeks a better understanding of the role of PARP in ischemic and diabetic wound healing, with a specific focus on angiogenesis and vasculogenesis. Full-Text PDF Open Archive

Bone Marrow-Derived Cell Accumulation in the Spinal Cord Is Independent of Peripheral Mobilization in a Mouse Model of Amyotrophic Lateral Sclerosis

Bone marrow-derived cells (BMDCs) are capable of migrating across the blood–brain barrier (BBB) and accumulating in the central nervous system (CNS) when transplanted into recipients conditioned with whole-body irradiation or chemotherapy. We used the chemotherapeutic agents busulfan and treosulfan to condition recipient mice for transplantation with bone marrow (BM) cells isolated from donor mice ubiquitously expressing green fluorescent protein. We attempted to increase the accumulation of BMDCs in the CNS by mobilization of BMDCs using either, or both, granulocyte colony-stimulating factor (GCSF) or plerixafor (AMD3100). We also used several concentrations of busulfan. We hypothesized that higher concentrations of busulfan and BMDC mobilization would increase numbers of GFP+ cells in the CNS. The doses of busulfan employed (60–125 mg/kg) all resulted in high levels of sustained chimerism (>85% 1 year post-transplant) in both the blood and BM of wild-type (WT) mice and an amyotrophic lateral sclerosis (ALS) mouse model. Moreover, cells accumulated within the CNS in a dose-, time-, and disease-dependent manner. Conditioning with the hydrophilic busulfan analog treosulfan, which is unable to cross the BBB efficiently, also resulted in a high degree of BM chimerism. However, few GFP+ BMDCs were found within the CNS of WT or ALS mice of treosulfan-conditioned mice. Mobilization of BMDCs into the circulation using GCSF and/or AMD3100 did not lead to increased accumulation of GFP+ BMDCs within the CNS of WT or ALS mice. Weekly analysis of BMDC accumulation revealed that BMDCs accumulated more rapidly and to a greater extent in the CNS of ALS mice conditioned with a high dose (125 mg/kg) of busulfan compared to a lower dose (80 mg/kg). The number of GFP+ BMDCs in the CNS labeling with the proliferation marker Ki67 increased in parallel with BMDC accumulation within the CNS. Our results indicate that establishment of high levels of blood and BM chimerism alone is not sufficient to induce BMDC accumulation within the CNS and that CNS conditioning is a crucial requirement for BMDC accumulation to occur. Moreover, it appears that proliferation of BMDCs that infiltrate the CNS is partly responsible for cell accumulation in busulfan-conditioned ALS mice.

Acute mobilization and migration of bone marrow-derived stem cells following anterior cruciate ligament rupture.

Little is known regarding acute local and systemic processes following anterior cruciate ligament (ACL) rupture. No study has elucidated whether bone marrow-derived mesenchymal stem cells (MSCs) are mobilized into circulation and recruited to the injured joint. In Part 1, Lewis rats were randomized to noninvasive ACL rupture (Rupture) or non-injured (Control) (n=6/group). After 72h, whole blood MSC concentration was assessed using flow cytometry. Synovial fluid and serum were assayed for stromal cell-derived factor (SDF)-1α and cartilage degeneration biomarkers, respectively. In Part 2, 12 additional rats were randomized and intravenously-injected with fluorescently-labeled allogenic MSCs. Cell tracking was performed using longitudinal, invivo and exvivo near-infrared (NIR) imaging and histology. Synovium SDF-1α and interleukin (IL)-17A immunostaining was performed. Serum was assayed for SDF-1α and 29 other cytokines. In Part 1, there was a significant increase in MSC concentration and synovial fluid SDF-1α in Rupture. No differences in cartilage biomarkers were observed. In Part 2, Rupture had significantly higher NIR signal at 24, 48, and 72h, indicating active recruitment of MSCs to the injured joint. Exvivo cell tracking demonstrated MSC localization in the synovium and myotendinous junction (MTJ) of the quadriceps. Injured synovia exhibited increased synovitis grade and higher degree of IL-17A and SDF-1α immunostaining. ACL rupture induced peripheral blood mobilization of MSCs and migration of intravenously-injected allogenic MSCs to the injured joint, where they localized in the synovium and quadriceps MTJ.

Ageing Impairs Ischaemia-Induced Neovascularisation by Attenuating the Mobilisation of Bone Marrow-Derived Progenitor Cells

Ageing Impairs Ischaemia-Induced Neovascularisation by Attenuating the Mobilisation of Bone Marrow-Derived Progenitor Cells

Aging impairs ischemia-induced neovascularization by attenuating the mobilization of bone marrow-derived angiogenic cells

BackgroundAging is associated with impaired ischemia-induced neovascularization. However, the effects of aging on bone marrow-derived angiogenic cell (BMDAC)-mediated vasculogenesis and on angiogenesis at the ischemic sites remain incompletely understood. Methods and resultsTwo- and 24-month old male C57Bl/6J mice were subjected to hindlimb ischemia. The levels of Sca1+/CXCR4+ BMDACs were determined post-ischemia by flow cytometry. In young mice, ischemia increased Sca1+/CXCR4+ BMDAC levels in the bone marrow and spleen at day 3 (p<0.001) and in the circulating blood at day 7 (p<0.01) post-ischemia. However, ischemia-induced elevation of progenitor cells was attenuated in the bone marrow, spleen and blood of old mice despite a preserved HIF-1α-mediated angiogenic response in the ischemic tissues. Irradiated young recipient mice engrafted with old bone marrow displayed reduced levels of Sca1+/CXCR4+ BMDACs in the bone marrow and circulating blood post-ischemia compared to recipients with young bone marrow. Ex vivo cultured BMDACs from old mice exhibited reduced SDF-1-stimulated migration (p<0.01) and a decrease in JAK-2 and AKT activation. However, the intrinsic angiogenic function of BMDACs, including VEGF secretion and promotion of endothelial cell tubule formation, was preserved with aging. Furthermore, facilitated mobilization of old bone marrow-derived mononuclear cells to the ischemic hindlimb by intramuscular injection enhanced ischemia-induced neovascularization in old mice in vivo (p<0.001). ConclusionsThe age-related impairment in ischemia-induced neovascularization is largely attributable to a marked attenuation of BMDAC mobilization with a preservation of intrinsic angiogenic function with age.

Combined therapy with sitagliptin plus granulocyte-colony stimulating factor in patients with acute myocardial infarction — Long-term results of the SITAGRAMI trial

BackgroundAutologous progenitor cell therapy comprising granulocyte-colony stimulating factor (G-CSF) for mobilization of bone-marrow derived progenitor cells (BMPCs) into peripheral blood and inhibition of dipeptidylpeptidase-IV by sitagliptin for enhanced myocardial recruitment of circulating BMPCs has been shown to improve survival after acute myocardial infarction (MI) in preclinical studies. In the SITAGRAMI trial we found that during short-term follow-up G-CSF plus sitagliptin (GS) failed to show a beneficial effect on cardiac function and clinical events in patients with acute MI that underwent successful PCI. The objective of the present analysis was to assess the impact of GS versus placebo treatment on long-term clinical outcomes of the SITAGRAMI trial patient population. MethodsIn the randomized, prospective, double-blind, placebo-controlled SITAGRAMI trial, 174 patients with acute MI were assigned to GS or placebo in a 1:1 ratio. The primary outcome for the present long-term analysis was the composite of death, MI or stroke on long-term follow-up. ResultsThe median [IQR] follow-up duration was 4.50 [3.56–5.95] years. The primary outcome occurred in 12.8% of patients assigned to placebo and 9.2% assigned to GS (HR 0.69, 95% CI 0.28–1.69; p=0.42). The incidence of the combined cardiovascular outcome was 47.7% in the placebo- and 41.4% in the GS-group (HR 0.75, 95% CI 0.48–1.18; p=0.21). Overall, there was no significant difference in MACCE rates between both treatment groups (p=0.41). ConclusionThese long-term follow-up data indicate that GS therapy does not improve clinical outcomes of patients with acute MI.

Targeting Bone Marrow to Potentiate the Anti-Tumor Effect of Tyrosine Kinase Inhibitor in Preclinical Rat Model of Human Glioblastoma.

Antiangiogenic agents caused paradoxical increase in pro-growth and pro-angiogenic factors and caused tumor growth in glioblastoma (GBM). It is hypothesized that paradoxical increase in pro-angiogenic factors would mobilize Bone Marrow Derived Cells (BMDCs) to the treated tumor and cause refractory tumor growth. The purposes of the studies were to determine whether whole body irradiation (WBIR) or a CXCR4 antagonist (AMD3100) will potentiate the effect of vatalanib (a VEGFR2 tyrosine kinase inhibitor) and prevent the refractory growth of GBM. Human GBM were grown orthotopically in three groups of rats (control, pretreated with WBIR and AMD3100) and randomly selected for vehicle or vatalanib treatments for 2 weeks. Then all animals underwent Magnetic Resonance Imaging (MRI) followed by euthanasia and histochemical analysis. Tumor volume and different vascular parameters (plasma volume (vp), forward transfer constant (Ktrans), back flow constant (kep), extravascular extracellular space volume (ve) were determined from MRI. In control group, vatalanib treatment increased the tumor growth significantly compared to that of vehicle treatment but by preventing the mobilization of BMDCs and interaction of CXCR4-SDF-1 using WBIR and ADM3100, respectively, paradoxical growth of tumor was controlled. Pretreatment with WBIR or AMD3100 also decreased tumor cell migration, despite the fact that ADM3100 increased the accumulation of M1 and M2 macrophages in the tumors. Vatalanib also increased Ktrans and ve in control animals but both of the vascular parameters were decreased when the animals were pretreated with WBIR and AMD3100. In conclusion, depleting bone marrow cells or CXCR4 interaction can potentiate the effect of vatalanib.