Effect and mechanism of hypoxia on differentiation of porcine-induced pluripotent stem cells into vascular endothelial cells.

Pigs are similar to humans in organ size and physiological function, and are considered as good models for studying cardiovascular diseases. The study of porcine-induced pluripotent stem cells (piPSC) differentiating into vascular endothelial cells (EC) is expected to open up a new way of obtaining high-quality seed cells. Given that the hypoxic environment has an important role in the differentiation process of vascular EC, this work intends to establish a hypoxia-induced differentiation system of piPSC into vascular EC. There is evidence that the hypoxia microenvironment in the initial stage could significantly improve differentiation efficiency. Further study suggests that the hypoxia culture system supports a combined effect of hypoxia inducible factors and their associated regulatory molecules, such as HIF-1α, VEGFA, FGF2, LDH-A, and PDK1, which can efficiently promote the lineage-specific differentiation of piPSC into EC. Most notably, the high level of ETV2 after 4 d of hypoxic treatment indicates that it possibly plays an important role in the promoting process of EC differentiation. The research is expected to help the establishment of new platforms for piPSC directional induction research, so as to obtain adequate seed cells with ideal phenotype and functionality.

Porcine Pluripotent Stem Cells Established from LCDM Medium with Characteristics Differ from Human and Mouse Extended Pluripotent Stem Cells.

Pluripotent stem cells (PSCs) have unlimited self-renewal and multifunctional development potential in vitro. Porcine PSCs are highly desirable due to the conserved characteristics between pigs and humans. Extended PSCs (EPSCs) are additionally capable of differentiating into embryonic (Em) and extraembryonic (E×Em) parts. Here, we employed the LCDM culture system (consisting of human LIF, CHIR99021, (S)-(+)-dimethindene maleate, and minocycline hydrochloride), which can establish EPSCs from humans and mice, to derive and maintain stable porcine PSCs (pLCDM) from in vivo blastocysts. Transcriptome analysis revealed the unique molecular characteristics of pLCDMs compared with early-stage embryos. Meanwhile, the parallels and differences in the transcriptome features among pLCDMs, human EPSCs, and mouse EPSCs were carefully analyzed and evaluated. Most noteworthy, the trophoblast lineage differentiation tendency of pLCDMs was clarified by inducing trophoblast-like cells and trophoblast stem cells (TSCs) in vitro. Further research found that 2 of the small molecules in LCDM culture system, (S)-(+)-dimethindene maleate (DiM) and minocycline hydrochloride (MiH), probably play a crucial role in promoting trophoblast lineage differentiation potential of pLCDMs.

Carboxymethyl chitosan based redox-responsive micelle for near-infrared fluorescence image-guided photo-chemotherapy of liver cancer.

High-efficient vectors for the co-delivery of photosensitizers and chemotherapeutics were urgently needed for the combination therapy. In this work, a redox-responsive micelle (PCL-SS-CMC-GA) was prepared for the co-delivery of doxorubicin (DOX) and pheophorbide A (PHA). Poly-ε-caprolactone was linked to carboxymethyl chitosan through a disulfide bond, which was easily broken in the reductive solution to release the payloads. The charge conversion property and glycyrrhetinic acid (GA) targeting ligand of the micelles effectively extended the average residence time (up to 18 times) in circulation and improved their intracellular uptake by HepG2 cells. The micelles exhibited an enhanced tumor accumulation and near infrared (NIR) imaging performance. More interestingly, this nanoplatform could fully exert the synergistic effect of DOX and PHA to improve the inhibition efficiency (with an inhibitory rate of 80.5 %) in vivo. With impressive photo-chemo theranostic and NIR imaging capability, PCL-SS-CMC-GA@DOX/PHA showed great potential in image-guided treatment of liver cancer.

Chitosan based pH-responsive polymeric prodrug vector for enhanced tumor targeted co-delivery of doxorubicin and siRNA.

The co-delivery of chemotherapeutic drugs and siRNA has gained increasing attentions owing to the enhanced antitumor efficacy over single administration. In this work, a chitosan-based pH-responsive prodrug vector was developed for the co-delivery of doxorubicin (DOX) and Bcl-2 siRNA. The accumulation of fabricated nanoparticles in hepatoma cells was enhanced by glycyrrhetinic acid receptor-mediated endocytosis. The cumulative release amount of the encapsulated DOX and siRNA reached 90.2 % and 81.3 % in 10 h, respectively. More strikingly, this nanoplatform can efficiently integrate gene- and chemo-therapies with a dramatically enhanced tumor inhibitory rate (88.0 %) in vivo. This co-delivery system may provide the latest strategy to meet the needs of combination therapies for tumors, offering safe and efficient improvements to the synergistic antitumor efficacy of gene-chemotherapies.

Chitosan capped pH-responsive hollow mesoporous silica nanoparticles for targeted chemo-photo combination therapy.

Combination therapy provides an efficient way to overcome the potential multidrug resistance and enhance anticancer efficacy. In this work, a biodegradable pH-responsive hollow mesoporous silica nanoparticle (HMSN-GM-CS-FA) was developed for co-delivery of pheophorbide a (PA) and doxorubicin (DOX). This drug delivery system possessed controlled particle size and larger inner hollow core, which endowed the nanoparticle with excellent encapsulation capacities. The uptake efficiency of drug loaded nanoparticles HMSNs-GM-CS-FA@DOX/PA in cancer cells was greatly improved by folic acid-mediated endocytosis. The nanocarrier showed excellent drug controlled release properties based on the pH-dependent swelling effect of the coating layer. More importantly, the nanoplatform could fully combine photothermal-, photodynamic- and chemotherapies to develop synergistic antitumor efficacy. This strategy of integrating multi-therapeutic functions in one single formulation promised a powerful route to construct intelligent co-delivery carriers for efficient combinational clinical application.

Influence of interfacial adsorption of glyceryl monostearate and proteins on fat crystallization behavior and stability of whipped-frozen emulsions.

The effect of interfacial competitive adsorption of glyceryl monostearate (GMS) with proteins and GMS-fat (anhydrous milk fat; coconut oil) interactions on the fat crystallization behavior and stability of whipped-frozen emulsions were investigated. The results indicated GMS retarded the nucleation of emulsified anhydrous milk fat, but accelerated crystal growth. A contrasting outcome was elicited by emulsified coconut oil. Increasing GMS concentration strengthened and weakened the structural networking within anhydrous milk fat and coconut oil emulsions, respectively, which was evidenced by the oscillatory rheology results. Anhydrous milk fat whipped-frozen emulsions were characterized by increased partial coalescence degree with increasing GMS concentration. However, lower partial destabilization index and insignificant effect of GMS was found in coconut oil systems. Confocal laser scanning micrographs revealed that big clumps of fat globules were present at air bubble surfaces in anhydrous milk fat whipped-frozen emulsions, while only some individual fat globules were observed in coconut oil systems.

Biodegradable N, O-carboxymethyl chitosan/oxidized regenerated cellulose composite gauze as a barrier for preventing postoperative adhesion.

Tissue adhesion is one of the most common complications after surgery (especially after abdominal surgery), causing notable influences after the damaged tissue has healed. A physical barrier placed between the wound site and the adjacent tissues is a convenient and highly effective technique to minimize or prevent abdominal adhesions. In this work, the N, O-carboxymethyl chitosan/oxidized regenerated cellulose (N, O-CS/ORC) composite gauze was prepared. The N, O-CS/ORC composite gauze is degradable; in addition, the gauze exhibits excellent antimicrobial functionality against S. aureus and E. coli bacteria. Moreover, the notable hemostatic efficacy of the N, O-CS/ORC composite gauze was confirmed in rabbit livers/ears as models. The results showed that the N, O-CS/ORC composite gauze is nontoxic toward normal cells and can restrain the adhesion of fibroblast cells, thereby indicating its potential use in preventing tissue adhesion. In addition, the rat models for abdominal defect-cecum abrasion were used to evaluate the efficacy of N, O-CS/ORC composite gauze in preventing tissue adhesions after surgery. The results indicated that the N, O-CS/ORC composite gauze can significantly prevent postsurgical peritoneal adhesions. Finally, the potential anti-adhesion mechanism of the N, O-CS/ORC composite gauze, which may attribute to the combination of barrier function and instinct activity of N, O-CS and ORC, was investigated.

Acid-sensitive polymeric vector targeting to hepatocarcinoma cells via glycyrrhetinic acid receptor-mediated endocytosis.

Liver cancer is one of the top death causing cancers, traditional treatments have not settled for the requirement of patients. In this work, a smart acid-responsive micelle based on glycyrrhetinic acid modified chitosan-polyethyleneimine-4-Hydrazinobenzoic acid-doxorubicin (GA-CS-PEI-HBA-DOX) was synthesized for targeted delivery of DOX to liver cancer. A dual pH-sensitive and receptor-mediated strategy has been exploited to enhance the delivery efficiency. The micelle possesses positive charges under pH 6.8 and can be turned into negative charges above pH 7.0, which help to be accumulated in tumor tissues (pH 6.0-7.0). In the intracellular environment (pH 4.5-6.5) of tumor cells, the pH-sensitive hydrazone bonds between DOX and GA-CS-PEI-HBA would break and release as much as 90.3% of the encapsulated payloads in 48 h. In addition, GA was modified to improve the targeting abilities. The micelles exhibited high lethality to HepG2 cells while showed much lower cytotoxicity to HUVEC cells. With high drug-loading capacity and the targeted release ability, the GA-CS-PEI-HBA-DOX micelle might be employed as a promising candidate for targeted cancer treatment.

Carbon nanotube-modified oxidized regenerated cellulose gauzes for hemostatic applications.

Functionalized carbon nanotubes have recently received interest because of their unique properties, especially in the biomedical field. In this research, unmodified multiwalled carbon nanotubes (MWCNTs), and functionalized carbon nanotubes with amino groups (MWCNTs-NH2) and carboxyl groups (MWCNTs-COOH) were grafted to oxidized regenerated cellulose (ORC) gauze to fabricate novel functionalized ORC, and the performance of the functionalized gauze was investigated. The functionalized ORC was characterized by FT-IR, XPS and SEM, which showed the different kinds of CNTs grafted on its surface. The XPS results demonstrated the successful incorporation of functionalized MWCNTs in the active layer of modified ORC gauze. Meanwhile, the specific surface area of the CNTs modified functionalized ORC gauze was improved in varying degrees, whereas the porosity was slightly decreased. Furthermore, hydrophilicity experiment results presented a significant increment in water uptake of the functionalized CNTs grafted to the surface of the ORC gauze. Results of the hemostatic performance test on rabbit ear artery and liver showed that compared with the original ORC gauze, the bleeding time was significantly reduced when using the functionalized CNTs modified ORC hemostatic gauze. Moreover, the results also showed that the MWCNTs-COOH/ORC functionalized gauze had outstanding hemostatic efficiency.

pH-Sensitive mesoporous silica nanoparticles for chemo-photodynamic combination therapy.

In order to optimize the chemotherapeutic efficacy of doxorubicin (DOX) and improve the photodynamic therapeutic effectiveness of rose bengal (RB), a mesoporous silica nanoparticle system was designed as the carrier of RB and DOX for chemo-photodynamic combination therapy. A pH-sensitive strategy has been exploited to enhance the delivery efficiency. Our results suggested that the production of singlet oxygen was independent of the release of RB while strongly influenced by the external DOX layer. This method showed several benefits, including accelerating cellular uptake of the payloads and enabling chemo-photodynamic combination therapy for synergistic cancer treatment. Our study provides a new way for co-delivery of chemotherapy agents and photosensitizers.

Biodegradable collagen sponge reinforced with chitosan/calcium pyrophosphate nanoflowers for rapid hemostasis.

Efficient and biodegradable hemostatic materials become increasingly important in civilian and military clinical. However, traditional hemostatic materials are difficult to achieve expected effects especially in parenchymal organs with rich vascularity. In facing these challenges, we designed a biodegradable collagen sponge reinforced with chitosan/calcium pyrophosphate nanoflowers (CPNFs-Col sponge) for rapid hemostasis. With specific performances, such as rapid water absorption ability, the positive surface rich in amino groups and high specific surface area (952.5m2g-1), the obtained CNPFs-Col sponge with optimized composition could activate the intrinsic pathway of coagulation cascade, induce haemocytes and platelets adherence, promote the blood clotting and achieve hemorrhage control in vitro and in vivo. In addition, the CNPFs-Col sponge can be completely biodegraded in 3 weeks, which is suitable for post-operative treatment and peritoneal adhesion prevention. It can be concluded that the CPNFs-Col sponge would become a promising candidate for clinical hemostatic applications.

Effective co-delivery of doxorubicin and curcumin using a glycyrrhetinic acid-modified chitosan-cystamine-poly(ε-caprolactone) copolymer micelle for combination cancer chemotherapy.

A glycyrrhetinic acid-modified chitosan-cystamine-poly(ε-caprolactone) copolymer (PCL-SS-CTS-GA) micelle was developed for the co-delivery of doxorubicin (DOX) and curcumin (CCM) to hepatoma cells. Glycyrrhetinic acid (GA) was used as a targeting unit to ensure specific delivery. Co-encapsulation of DOX and CCM was facilitated by the incorporation of poly(ε-caprolactone) (PCL) groups. The highest drug loading content was 19.8% and 8.9% (w/w) for DOX and CCM, respectively. The PCL-SS-CTS-GA micelle presented a spherical or ellipsoidal geometry with a mean diameter of approximately 110nm. The surface charge of the micelle changed from negative to positive, when the pH value of the solution decreased from 7.4 to 6.8. Meanwhile, it also exhibited a character of redox-responsive drug release and GA/pH-mediated endocytosis in vitro. In simulated body fluid with 10mM glutathione, the release rate in 12h was 80.6% and 67.2% for DOX and CCM, respectively. The cell uptake of micelles was significantly higher at pH 6.8 than pH 7.4. The combined administration of DOX and CCM was facilitated by PCL-SS-CTS-GA micelle. Results showed that there was strong synergic effect between the two drugs. The PCL-SS-CTS-GA micelle might turn into a promising and effective carrier for improved combination chemotherapy.