Clinical characteristics and prognostic factors of patients with Philadelphia-negative myeloproliferative neoplasm accelerated/blast phase / 中华血液学杂志

Objective: To evaluate the clinical characteristics and prognostic factors of patients with Philadelphia-negative myeloproliferative neoplasm-accelerated phase/blast phase (MPN-AP/BP) . Methods: A total of 67 patients with MPN-AP/BP were enrolled from February 2014 to December 2021 at the Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences. Their clinical features and prognostic factors were analyzed retrospectively. Results: ① Sixty-seven patients with MPN-AP/BP with a median age of 60 (range, 33-75) years, including 31 males (46.3% ) and 36 females (53.7% ) , were analyzed. Forty-eight patients progressed from primary myelofibrosis (PMF) , and 19 progressed from other myeloproliferative neoplasms (MPNs) , which included polycythemia vera, essential thrombocythemia, and MPN unclassifiable. Patients who progressed from PMF had higher lactate dehydrogenase (LDH) levels than those who progressed from other MPNs (925.95 vs. 576.2 U/L, P=0.011) , and there were higher proportions of patients who progressed from PMF with splenomegaly (81.4% vs. 57.9% , P=0.05) , a myelofibrosis grade of ≥2 (93.6% vs. 63.2% , P=0.004) , and a shorter duration from diagnosis to the transformation to AP/BP (28.7 vs. 81 months, P=0.001) . ② JAK2V617F, CALR, and MPLW515 were detected in 41 (61.2% ) , 13 (19.4% ) , and 3 (4.5% ) patients, respectively, whereas 10 (14.9% ) patients did not have any driver mutations (triple-negative) . Other than driver mutations, the most frequently mutated genes were ASXL1 (42.2% , n=27) , SRSF2 (25% , n=16) , SETBP1 (22.6% , n=15) , TET2 (20.3% , n=13) , RUNX1 (20.3% , n=13) , and TP53 (17.2% , n=11) . The ASXL1 mutation was more enriched (51.1% vs. 21.1% , P=0.03) , and the median variant allele fraction (VAF) of the SRSF2 mutation (median VAF, 48.8% vs. 39.6% ; P=0.008) was higher in patients who progressed from PMF than those who progressed from other MPNs. ③ In the multivariate analysis, the complex karyotype (hazard ratio, 2.53; 95% confidence interval, 1.06-6.05; P=0.036) was independently associated with worse overall survival (OS) . Patients who received allogeneic stem cell transplantation (allo-HSCT) (median OS, 21.3 vs. 3 months; P=0.05) or acute myeloid leukemia-like (AML-like) therapy (median OS, 13 vs. 3 months; P=0.011) had significantly better OS than those who received supportive therapy. Conclusion: The proportions of patients with PMF-AP/BP with splenomegaly, myelofibrosis grade ≥2, a higher LDH level, and a shorter duration from diagnosis to the transformation to AP/BP were higher than those of patients with other Philadelphia-negative MPN-AP/BP. The complex karyotype was an independent prognostic factor for OS. Compared with supportive therapy, AML-like therapy and allo-HSCT could prolong the OS of patients with MPN-AP/BP.

Collagenase-labile polyurethane urea synthesis and processing into hollow fiber membranes.

As a means to stimulate wound healing, a hollow fiber membrane system might be placed within a wound bed to provide local and externally regulated controlled delivery of regenerative factors. After sufficient healing, it would be desirable to triggerably degrade these fibers as opposed to pulling them out. Accordingly, a series of enzymatically degradable thermoplastic elastomers was developed as potential hollow fiber base material. Polyurethane ureas (PUUs) were synthesized based on 1, 4-diisocyanatobutane, polycaprolactone (PCL) diol and polyethylene glycol (PEG) at different molar fractions as soft segments, and collagenase-sensitive peptide GGGLGPAGGK-NH2 as a chain extender (defined as PUU-CLxEGy-peptide, where x and y are the respective molar percents). In these polymers, PEG in the polymer backbone decreased tensile strengths and initial moduli of solvent-cast films in the wet state, while increasing water absorption. Collagenase degradation was observed at 75% relative PEG content in the soft segment. Control PUUs with putrescine or nonsense peptide chain extenders did not degrade acutely in collagenase. Conduits electrospun from PUU-CL25EG75-peptide and PUU-CL50EG50-peptide exhibited appropriate mechanical strength and sustained release of a model protein from the tube lumen for 7 days. Collapse of PUU-CL25EG75-peptide tubes occurred after collagenase degradation for 3 days. In conclusion, through molecular design, synthesis and characterization, a collagenase-labile PUU-CL25EG75-peptide polymer was identified that exhibited the desired traits of triggerable lability, processability, and the capacity to act as a membrane to facilitate controlled protein release.

Gene expression mediated by dendrimer/DNA complexes encapsulated in biodegradable polymer microspheres.

A convenient and effective 'ultrasonic dispersion method' was used to fabricate vector/DNA complexes encapsulated microspheres. Polyamidoamine (PAMAM) dendrimer/DNA complexes protected by a water-soluble polymer, poly-alpha,beta-[N-(2-hydroxyethyl)-L-aspartamide] (PHEA), were encapsulated in a polymer film mainly composed of cholic acid functionalized star poly(DL-lactide), which degraded through surface erosion mechanism with a fast degradation rate. The PAMAM/DNA complexes encapsulated polymer film was then immersed in ethanol and ultrasonicated to afford the microspheres. The in vitro gene transfections showed PAMAM/DNA complexes protected by PHEA exhibited a much higher transfection activity compared with PAMAM/DNA complexes without the protection by PHEA. The expressions of pGL3-Luc in HEK293 cells could be effectively mediated by the polymer film and microspheres with the presence of PHEA. The ultrasonic dispersion method, which did not involve toxic organic solvents, could keep the bioactivity of DNA and offer good control over the size of microspheres.

Dendrimer/DNA complexes encapsulated functional biodegradable polymer for substrate-mediated gene delivery.

BACKGROUND: To overcome the extracellular barriers in gene delivery and direct gene delivery to target tissues, substrate-mediated transfection, which sustains the release of naked DNA or vector/DNA complexes, and also supports cell growth, has been developed. METHODS: In the present study, polyamidoamine (PAMAM) dendrimer/DNA complexes encapsulated functional biodegradable polymer films for substrate-mediated gene delivery were prepared. To maintain the activity of DNA during dehydration, the dendrimer/DNA complexes were encapsulated in a water soluble polymer, poly alpha,beta-[N-(2-hydroxyethyl)-(L)-aspartamide], and then deposited on or sandwiched in functional polymer films with a fast degradation rate to mediate gene transfection. The in vitro gene transfections of pGL3-Luc and pEGFP-C1 plasmids in HEK293 cells mediated by different films were studied. For comparison, the transfection mediated by the film fabricated by conventional linear poly((DL)-lactide) was also investigated. RESULTS: The expression of pGL3-Luc and pEGFP-C1 plasmids could effectively be mediated by the PAMAM/DNA complexes deposited or sandwiched polymer films, with transfection efficiencies comparable to that of solution-based transfections. The cells on the functionalized star poly((DL)-lactide) film exhibited much higher gene expression compared to the cells on the conventional linear poly((DL)-lactide) film because the fast degradation rate of star poly((DL)-lactide) facilitated the access of PAMAM/DNA complexes for the cells seeded on the film. In addition, the films did not exhibit any additional cytotoxicity to the cells during the degradation and transfection. CONCLUSIONS: The fast degrading functional polymer has great potential for localized transfection.

Fabrication and in vitro drug release study of microsphere drug delivery systems based on amphiphilic poly-alpha,beta-[N-(2-hydroxyethyl)-L-aspartamide]-g-poly(L-lactide) graft copolymers.

Biodegradable amphiphilic graft copolymers with different compositions were synthesized by grafting poly(L-lactide) (PLLA) sequences onto a water-soluble poly-alpha,beta-[N-(2-hydroxyethyl)-L-aspartamide] (PHEA) backbone. The critical micelle concentration (CMC) of the graft polymers was determined by fluorescence probe technique. Using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, the graft polymers were proved to have low cytotoxicity. Based on the specific physicochemical property of the graft copolymers, submicron sized microsphere drug delivery systems were prepared by a very convenient "ultrasonic dispersion method", which did not involve toxic organic solvents. The drug-loaded microspheres had a regular spherical shape with a narrow size distribution. A hydrophobic drug, prednisone acetate, was encapsulated into polymeric microspheres and the in vitro drug release was studied.

Cholic acid functionalized star poly(DL-lactide) for promoting cell adhesion and proliferation.

Cholic acid functionalized star poly(DL-lactide) was synthesized through the ring-opening polymerization of DL-lactide initiated by cholic acid. The properties and cell behaviour of the cholic acid functionalized star poly(DL-lactide) were investigated as compared with linear poly(DL-lactide)s with different molecular weights and a star poly(DL-lactide) initiated by glycerol. In comparison to linear poly(DL-lactide)s, the cholic acid functionalized star poly(DL-lactide) had better wettability and slightly higher surface energy. The cell adhesion and proliferation on different materials were evaluated using two types of cells, 3T3 mouse fibroblasts and ECV304 human endothelial cells. Compared with the linear poly(DL-lactide)s, the cholic acid functionalized star poly(DL-lactide) showed obviously improved property for cell adhesion. The cell proliferation on the cholic acid functionalized star poly(DL-lactide) was also enhanced. The improvement in cell proliferation was not so significant as compared with the improvement in cell adhesion. This modification strategy provides an effective and simple way to promote cell attachment and growth in tissue engineering.

Dendrimer/DNA complexes encapsulated in a water soluble polymer and supported on fast degrading star poly(DL-lactide) for localized gene delivery.

Polyamidoamine (PAMAM) dendrimer/DNA complexes encapsulated in a water soluble polymer, poly-alpha,beta-[N-(2-hydroxyethyl)-l-aspartamide], were supported on a cholic acid functionalized star poly(DL-lactide) film with a fast degradation rate to mediate localized gene delivery. The in vitro gene transfections of two types of cells, HEK293 and NIH3T3, were investigated. The expressions of pGL3-Luc and pEGFP-C1 plasmids in HEK293 cells indicated that the star poly(DL-lactide) supported PHEA encapsulated PAMAM/DNA complexes could effectively mediate transfection, with transfection efficiencies which were comparable to that of solution-based transfections. Whereas the PAMAM/DNA complexes directly supported on the star poly(DL-lactide) film showed a much lower expression level for HEK293, which indicated the existence of PHEA played an important role in the efficient transfection. The solid support-based transfection for NIH3T3 cells exhibited higher expressions of pGL3-Luc compared with the solution-based transfection. Encapsulating PAMAM/DNA complexes in PHEA could further improve the gene expression in NIH3T3. During the cellular transfection, the degradation of the cholic acid functionalized star poly(DL-lactide) film could be obviously detected and the degradation did not show any unfavorable effects on the gene expression, which implied this solid support-based gene delivery device had great potential for localized transfection.

Synthesis of novel cholic acid functionalized branched oligo/poly(epsilon-caprolactone)s for biomedical applications.

Novel cholic acid functionalized branched oligo/poly(epsilon-caprolactone)s were synthesized through the ring-opening polymerization of epsilon-caprolactone initiated by cholic acid with hydroxyl groups. The molecular weight of the branched polymers can be adjusted by controlling the feed ratio of the initiator cholic acid to the monomer epsilon-caprolactone. Comparing with linear homopolymer poly(epsilon-caprolactone) (PCL), these branched oligo/poly(epsilon-caprolactone)s show much faster hydrolytic degradation rates, implies that our approach provides a convenient and effective strategy to accelerate degradation of the biodegradable polymers with slow degradation rates such as PCL. The cell culture experiment indicates the incorporation of cholic acid moiety to the polymer chain can improve both cell adherence and proliferation obviously.