ABSTRACT
BACKGROUND: Although a large number of related studies have been carried out, there is still a lack of practical methods to amplify hematopoietic stem cells(HSCs)in vitro.Mesenchymal stem cells(MSCs)secrete a variety of cytokines that promote the HSCs proliferation and inhibit their differentiation. These cytokines play an important role in maintaining the hematopoietic microenvironment and regulating HSCs function. OBJECTIVE:To investigate the effect of bone marrow MSCs on the proliferation of HSCs in vitro under different coculture modes. METHODS:Mesenchymal stem cells from the bone marrow of C57BL/6 mice were cultured in vitro using the whole bone marrow adherent culture. CD117+cells (HSCs) were sorted from passage 3 cells by using miniMACS magnetic beads sorting. Then, CD117+cells were co-cultured with MSCs under different coculture models, including single culture of HSCs (control group), Transwell coculture (upper chamber, HSCs; lower chamber, MSCs) and two-dimensional contact coculture (coculturing HSCs and MSCs in 24-well plates). The morphology of HSCs was observed under phase contrast microscope and fluorescence microscope, and the number of active cells of HSCs was counted at 1, 3, 5, and 7 days after coculture. RESULTS AND CONCLUSION: During the coculture of 1-7 days, the number of HSCs in the two groups was increased with culture time (P <0.05). After 3 days of coculture, HSCs in each group was grown into the logarithmic growth phase, and morphological changes in some HSCs were detected at 5 days of coculture. At 7 days of coculture, the viabilities of HSCs in different culture models were ranked as follows: single culture model < Transwell coculture model < two-dimensional contact coculture model (P < 0.05). These findings suggest that MSCs can effectively promote the proliferation of HSCs in vitro,and the promotion effect is increased under contact coculture conditions.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the influencing factors of nosocomial infection in adult patients with acute myeloid leukemia (AML) and its control strategies.</p><p><b>METHODS</b>The clinical data of 109 patients with AML treated in our hospital from June 2014 to June 2017 were retrospectively analyzed. The clinical factors were analyzed retrospectively, and the influencing factors of infection after chemotherapy were explored.</p><p><b>RESULTS</b>A total of 109 patients received chemotherapy for 267 case-times, the infection occurred in 168 case-times, the nosocomial infection rate was 62.92%, the main affected sites included upper respiratory tract and lung. 155 samples from 168 case-times infection patients were collected and cultured, 32 pathogens were obtained with a positive rate 20.6% (32/155), including 14 Gram-negative bacteria, 9 Gram-positive bacteria and 4 strains of fungi and 5 strains of other pathogens. Statistics showed that the patient's age over 40 years old, hospitalization in spring and summer, glucocorticoid therapy, high intensity chemotherapy, neutrophil count, white blood cell count and hemoglobin content were the independent risk factors for infection after chemotherapy in AML patients (P<0.05).</p><p><b>CONCLUSION</b>The age of more than 40 years old, hospitalization in spring and summer, glucocorticoid therapy, high-intensity chemotherapy, white blood cell count, neutrophil count and hemoglobin content are the independent risk factors for infection after chemotherapy in the AML patients with the above-mentioned characteristics, they should be closely monitored, and chemotherapy intensity should be controled, so as to control the occurrence of infection; and in the event of infection, a timely powerful anti-infective treatment would be indispensable.</p>
Subject(s)
Adult , Humans , Cross Infection , Hospitalization , Leukemia, Myeloid, Acute , Retrospective Studies , Risk FactorsABSTRACT
<p><b>OBJECTIVE</b>To study the effect and mechanism of shh and mesenchymal stem cell（MSC）synergism on the proliferation of hematopoietic stem cells in noninvasive co-culture system in vitro.</p><p><b>METHODS</b>The mesenchymal stem cells were cultured in vitro，CD34 cells were sorted by mini MACS magnetic bead separator，flow cytometry was used to identify the purity of 2 cells. CD34 cells and MSCs were seeded to upper and low of transwell respecibely for non-contact coculture，and add exogenous shh protein for intervenece. The number of MSCs and HSCs，the total amount of RNA，the expression of ki67 and Tie-2 mRNA of HSC，the expression of VEGF and Ang-1 mRNA of MSC were detected for investigating the condition of cell proliferation and the expression of angiogenic factors.</p><p><b>RESULTS</b>The total number of cells，the total amount of RNA and the relative expression of ki67, Tie-2, VEGF and Ang-1 in non-contact co-culture group increased and showed the following trends on the 7th day：the above-mentioned indexes in group MSC + HSC, group shh + HSC were higher than those in group HSC, while those in MSC + shh + HSC Group was higher than those in MSC + HSC and shh + HSC group.</p><p><b>CONCLUSION</b>Angiogenic factors help MSC to proliferate HSC and amplify the CD34 hematopoietic stem/progenitor cells by shh and MSC synergism in vitro coculture system which may be related with angiogenic factors.</p>