Zenghui Liu

Cotransplantation of bone marrow-derived mesenchymal stem cells in haploidentical hematopoietic stem cell transplantation in patients with severe aplastic anemia: an interim summary for a multicenter phase II trial results

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) for severe aplastic anemia (SAA) is mainly limited by the high incidence of graft failure and GvHD. Mesenchymal stem cells (MSCs) have been shown to support hematopoiesis in vivo and to display potent immunosuppressive effects to prevent or treat GvHD after HSCT. In a multicenter phase II trial, we developed an approach with co-transplantation of MSCs in patients undergoing haplo-HSCT. Forty-four patients with SAA were included. The conditioning regimen included busulfan, cyclophosphamide and thymoglobulin (ATG). The recipients received cyclosporin A (CsA), mycophenolate mofetil and short-term methotrexate for GvHD prophylaxis. Three out of 44 patients, who died early before hematopoietic engraftment, were not assessed. Evaluable patients (97.6%; 40/41) achieved hematopoietic reconstitution and sustained full donor chimerism. The median time for myeloid engraftment was 12 days (range 8–21 days) and for platelet engraftment was 19 days (range 8–154 days). The incidence was 29.3% for grade II–IV acute GvHD and 14.6% for chronic GvHD. The overall survival was 77.3% with a median 12-month (range 0.9–30.8) follow-up for surviving patients. These data suggest that co-transplantation of MSCs could reduce the risk of graft failure and severe GvHD in haplo-HSCT for SAA.

A comparative study of low energy radiation response of AlAs, GaAs and GaAs/AlAs superlattice and the damage effects on their electronic structures

In this study, the low energy radiation responses of AlAs, GaAs and GaAs/AlAs superlattice are simulated and the radiation damage effects on their electronic structures are investigated. It is found that the threshold displacement energies for AlAs are generally larger than those for GaAs, i.e., the atoms in AlAs are more difficult to be displaced than those in GaAs under radiation environment. As for GaAs/AlAs superlattice, the Ga and Al atoms are more susceptible to the radiation than those in the bulk AlAs and GaAs, whereas the As atoms need comparable or much larger energies to be displaced than those in the bulk states. The created defects are generally Frenkel pairs, and a few antisite defects are also created in the superlattice structure. The created defects are found to have profound effects on the electronic properties of GaAs/AlAs superlattice, in which charge transfer, redistribution and even accumulation take place, and band gap narrowing and even metallicity are induced in some cases. This study shows that it is necessary to enhance the radiation tolerance of GaAs/AlAs superlattice to improve their performance under irradiation.

Allogeneic Bone Marrow-Derived Mesenchymal Stromal Cells Expanded In Vitro for Treatment of Aplastic Anemia: A Multicenter Phase II Trial: Mesenchymal Stromal Cells for Aplastic Anemia

We conducted a phase II, noncomparative, multicenter study to assess the efficacy and safety of allogeneic bone marrow‐derived mesenchymal stromal cells (BM‐MSCs) expanded in vitro for patients with aplastic anemia (AA) refractory to immunosuppressive therapy. Seventy‐four patients from seven centers received allogeneic BM‐MSCs at a dose of 1–2 × 106 cells/kg per week for 4 weeks. Responses were assessed at 0.5, 1, 2, 3, 6, 9, and 12 months after the first cells infusion. Patients with response at 1 month continued to receive four infusions. All patients were evaluable. The overall response rate was 28.4% (95% confidence interval, 19%–40%), with 6.8% complete response and 21.6% partial response. The median times to response of leukocytic, erythrocytic, and megakaryocytic linages were 19 (range, 11–29), 17 (range, 12–25), and 31 (range, 26–84) days, respectively. After median follow‐up of 17 months, overall survival was 87.8%. Seven patients developed transitory and mild headache and fever, but no other adverse events were observed. Antithymocyte globulin used in previous treatment and no activated infection throughout treatment were predictors for response. Allogeneic BM‐MSCs infusion is a feasible and effective treatment option for refractory AA. The trial was registered at www.clinicaltrials.gov as NCT00195624. Stem Cells Translational Medicine 2017;6:1569–1575

Impact of isovalent and aliovalent substitution on the mechanical and thermal properties of Gd 2 Zr 2 O 7

In this study, a density functional theory method is employed to investigate the effects of isovalent and aliovalent substitution of Sm3+ on the phase stability, thermo-physical properties and electronic structure of Gd2Zr2O7. It is shown that the isovalent substitution of Sm3+ for Gd3+ results in the formation of Gd2Zr2O7-Sm2Zr2O7 solid solution, which retains the pyrochlore structure and has slight effects on the elastic moduli, ductility, Debye temperature and band gap of Gd2Zr2O7. As for the aliovalent substitution of Sm3+ for Zr4+ site, a pyrochlore-to-defect fluorite structural transition is induced, and the mechanical, thermal properties and electronic structures are influenced significantly. As compared with the Gd2Zr2O7, the resulted Gd2SmyZr2-yO7 compositions have much smaller elastic moduli, better ductility and smaller Debye temperature. Especially, an amount of electrons distribute on the fermi level and they are expected to have larger thermal conductivity than Gd2Zr2O7. This study suggests an alternative way to engineer the thermo-physical properties of Gd2Zr2O7 and will be beneficial for its applications under stress and high temperature.

Cotransplantation of haploidentical hematopoietic stem cells and allogeneic bone marrow-derived mesenchymal stromal cells as a first-line treatment in very severe aplastic anemia patients with refractory infections

In patients with very severe aplastic anemia (VSAA), neutropenia is prolonged and persistent, resulting in refractory overwhelming infections. Hematopoiesis recovery is urgently needed.

In patients with chronic aplastic anemia, bone marrow–derived MSCs regulate the Treg/Th17 balance by influencing the Notch/RBP-J/FOXP3/RORγt pathway

The standard treatment for aplastic anemia (AA) in young patients is a matched sibling hematopoietic stem cell transplant. Transfusion of a chronic AA patient with allogeneic bone marrow–derived mesenchymal stromal cells (BMMSCs) is currently being developed as a cell-based therapy, and the safety and efficacy of such transfusions are being continuously improved. Nevertheless, the mechanisms by which BMMSCs exert their therapeutic effects remain to be elucidated. In this study, mesenchymal stromal cells (MSCs) obtained from bone marrow donors were concentrated and intravenously injected into 15 chronic AA patients who had been refractory to prior immunosuppressive therapy. We showed that BMMSCs modulate the levels of Th1, Th2, Th17 and Treg cells, as well as their related cytokines in chronic AA patients. Furthermore, the percentages of Th1 and Th17 cells among the H-MSCs decreased significantly, while the percentage Treg cells increased. The Notch/RBP-J/FOXP3/RORγt pathway was involved in modulating the Treg/Th17 balance after MSCs were transfused in vitro. Additionally, the role played by transfused MSCs in regulating the Treg/Th17 balance via the Notch/RBP-J/FOXP3/RORγt pathway was further confirmed in an AA mouse model. In summary, in humans with chronic AA, BMMSCs regulate the Treg/Th17 balance by affecting the Notch/RBP-J/FOXP3/RORγt pathway.

Haploidentical hematopoietic SCT using helical tomotherapy for total-body irradiation and targeted dose boost in patients with high-risk/refractory acute lymphoblastic leukemia

A novel conditioning regimen using helical tomotherapy (HT) was developed to deliver 10 Gy for total body irradiation (TBI) and simultaneously augment dose to 12 Gy for targeted dose boost to total marrow, central nervous system leukemia, and extramedullary disease sites in patients with high-risk or relapsed/refractory acute lymphoblastic leukemia (ALL) receiving haploidentical allogeneic hematopoietic stem cell transplantation (allo-HSCT). Fourteen patients were included, eight of these patients were in first complete remission (CR1), one was in CR2, one had a partial response and four patients had refractory disease at transplantation. The median delivered average dose was 11.395 Gy (range 10.06–12.17). The median planning target volume D95 was 8.2 Gy (range 7.52–9.01). The median delivered dose to skeleton bone with active bone marrow sites was 12.685 Gy (range 11.12–13.52). The results of this trial suggest that using HT TBI confers satisfactory immunosuppression and excellent eradication of malignant cells in patients with high-risk ALL undergoing allo-HSCT, especially in those with refractory ALL. After a median follow-up of 14.6 months (range 4–28), four patients experienced non-relapse mortality, ten patients are alive in durable CR including remission of extramedullary leukemic infiltration. One-year overall survival and disease-free survival rates post-transplantation were both 70.7%.