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Background: Bone Marrow Mononuclear Cells (BM-MNC) constitute a promising alternative for the treatment of Chronic Limb-Threatening ischemia (CLTI), a disease characterized by extensive blockade of peripheral arteries, clinically presenting as excruciating pain at rest and ischemic ulcers which may lead to gangrene and amputation. BM-MNC implantation has shown to be efficient in promoting angiogenesis and ameliorating ischemic symptoms in CLTI patients. However, the variability seen between clinical trials makes necessary a further understanding of the mechanisms of action of BM-MNC, and moreover, to improve trial characteristics such as endpoints, inclusion/exclusion criteria or drug product compositions, in order to implement their use as stem-cell therapy.Materials: Herein, the effect of REX-001, a human-BM derived cell suspension enriched for mononuclear cells, granulocytes and CD34+ cells, has been assessed in a murine model of CLTI. In addition, a REX-001 placebo solution containing BM-derived red blood cells (BM-RBCs) was also tested. Thus, 24 h after double ligation of the femoral artery, REX-001 and placebo were administrated intramuscularly to Balb-c nude mice (n:51) and follow-up of ischemic symptoms (blood flow perfusion, motility, ulceration and necrosis) was carried out for 21 days. The number of vessels and vascular diameter sizes were measured within the ischemic tissues to evaluate neovascularization and arteriogenesis. Finally, several cell-tracking assays were performed to evaluate potential biodistribution of these cells.Results: REX-001 induced a significant recovery of blood flow by increasing vascular density within the ischemic limbs, with no cell translocation to other organs. Moreover, cell tracking assays confirmed a decrease in the number of infused cells after 2 weeks post-injection despite on-going revascularization, suggesting a paracrine mechanism of action.Conclusion: Overall, our data supported the role of REX-001 product to improve revascularization and ischemic reperfusion in CLTI.

Background: Bone marrow (BM) produces hematopoietic and progenitor cells that contribute to distant organ inflammation and repair. Chronic obstructive pulmonary disease (COPD) is characterized by defective lung repair. Yet, BM composition has not been previously characterized in COPD patients. Methods: In this prospective and controlled study, BM was obtained by sternum fine-needle aspiration in 35 COPD patients and 25 healthy controls (10 smokers and 15 never-smokers). BM cell count and immunophenotype were determined by microscopy and flow cytometry, respectively. Circulating inflammatory (C-reactive protein, IL-6, IL-8) and repair markers (HGF, IGF, TGF-beta, VEGF) were quantified by ELISA. Results were integrated by multi-level network correlation analysis. Results: We found that: (1) there were no major significant pair wise differences between COPD patients and controls in the BM structural characteristics; (2) multi-level network analysis including patients and controls identifies a relation between immunity, repair and lung function not previously described, that remains in the COPD network but is absent in controls; and (3) this novel network identifies eosinophils as a potential mediator relating immunity and repair, particularly in patients with emphysema. Conclusions: Overall, these results suggest that BM is activated in COPD with impaired repair capacity in patients with more emphysema and/or higher circulating eosinophils., This study has been supported, in part, by Fondo de Investigacion Sanitaria, Instituto Carlos III (PI08/0780), CIBERES and beca SEPAR.

Background: Bone marrow aspiration and biopsy are diagnostic methods in the study of hematological diseases. Complications are rare. Knowing the morbidity and mortality related to the procedure is essential in order to implement preventive behaviors and improvement plans. Objective: To determine the incidence of complications in patients over 18 years who were undergone to bone marrow biopsy and aspiration in a university hospital between October 2013 and May of 2015. Furthermore, frequency, socio-demographic and clinical characteristics were established as well. Materials & methods: Observational, descriptive and retrospective study. The unit of analysis was biopsies and bone marrow aspirations. The information was obtained from the database of outpatient hematology ward, into the program Group of Education and Monitoring of Egress (GESE) of the Hematology Service of Hospital de San José (Bogotá, Colombia), and from medical records. Results: A total of 1252 bone marrow aspirates and biopsies were performed on 914 patients. Seventy-seven complications were reported, which corresponds to 6.15% of all documented procedures. The most frequent complication was: pain (100%), being more affected the women (66%), OR 1,91(IC 1,18-3,11) p=0,003. Regard to pathology diagnosis, 53.2% of biopsies were histologically normal hematopoiesis, followed by 16.8% for chronic myeloproliferative syndromes, which was the diagnosis most commonly associated with bleeding events (40%):OR 8,9 (IC 1,2-66,44) p=0,006, and death (1.3%). Conclusion: Pain was the most frequently reported complication, and among bleeding complications, chronic myeloproliferative disorders were the most common diagnosis. The largest number of complications in women may be related to the anatomical differences between the genders. It is recommended to improve post-procedure analgesia and prospective studies to establish association between complications and diagnosis.

[Background]: Megakaryopoiesis allows platelet formation, which is necessary for coagulation, also playing an important role in different pathologies. However, this process remains to be fully characterized. C3G, an activator of Rap1 GTPases, is involved in platelet activation and regulates several differentiation processes. [Methods]: We evaluated C3G function in megakaryopoiesis using transgenic mouse models where C3G and C3GΔCat (mutant lacking the GEF domain) transgenes are expressed exclusively in megakaryocytes and platelets. In addition, we used different clones of K562, HEL and DAMI cell lines with overexpression or silencing of C3G or GATA-1. [Results]: We found that C3G participates in the differentiation of immature hematopoietic cells to megakaryocytes. Accordingly, bone marrow cells from transgenic C3G, but not those from transgenic C3GΔCat mice, showed increased expression of the differentiation markers CD41 and CD61, upon thrombopoietin treatment. Furthermore, C3G overexpression increased the number of CD41+ megakaryocytes with high DNA content. These results are supported by data obtained in the different models of megakaryocytic cell lines. In addition, it was uncovered GATA-1 as a positive regulator of C3G expression. Moreover, C3G transgenic megakaryocytes from fresh bone marrow explants showed increased migration from the osteoblastic to the vascular niche and an enhanced ability to form proplatelets. Although the transgenic expression of C3G in platelets did not alter basal platelet counts, it did increase slightly those induced by TPO injection in vivo. Moreover, platelet C3G induced adipogenesis in the bone marrow under pathological conditions. [Conclusions]: All these data indicate that C3G plays a significant role in different steps of megakaryopoiesis, acting through a mechanism dependent on its GEF activity., This work was supported by grants from the Spanish Ministry of Economy and Competitiveness [SAF2013–48210-C2–1-R and SAF2016–76588-C2–2-R to CG, SAF2013–48210-C2–2-R and SAF2016–76588-C2–1-R to AP], and by two grants from the Council of Education of Junta de Castilla y León, Spain [SA157A12–1 and SA017U16 to CG]. All funding was cosponsored by the European FEDER Program.