Early application of continuous high-volume haemofiltration can reduce sepsis and improve the prognosis of patients with severe burns.

BACKGROUND: In the early stage of severe burn, patients often exhibit a high level of inflammatory mediators in blood and are likely to develop sepsis. High-volume haemofiltration (HVHF) can eliminate these inflammatory mediators. We hypothesised that early application of HVHF may be beneficial in reducing sepsis and improving the prognosis of patients with severe burns. METHODS: Adults patients with burns ≥ 50% total burn surface area (TBSA) and in whom the sum of deep partial and full-thickness burn areas was ≥ 30% were enrolled in this randomised prospective study, and they were divided into control (41 cases) and HVHF (41 cases) groups. Patients in the control group received standard management for major burns, whereas the HVHF group additionally received HVHF treatment (65 ml/kg/h for 3 consecutive days) within 3 days after burn. The incidence of sepsis and mortality, some laboratory data, levels of inflammatory cytokines in the blood, HLA-DR expression on CD14+ peripheral blood monocytes, the proportion of CD25+Foxp3+ in CD4+ T lymphocytes, and the counts of CD3+, CD4+ and CD8+ T lymphocytes were recorded within 28 days post-burn. RESULTS: The incidence of sepsis, septic shock and duration of vasopressor treatment were decreased significantly in the HVHF group. In addition, in the subgroup of patients with burns ≥ 80% TBSA, the 90-day mortality showed significant decreases in the HVHF group. The ratio of arterial oxygen partial pressure to the fraction of inspiration oxygen was improved after HVHF treatment. In the patients who received HVHF treatment, the blood levels of inflammatory cytokines, including tumour necrosis factor-α, interleukin (IL)-1ß, IL-6 and IL-8, as well as the blood level of procalcitonin were found to be lower than in the control group. Moreover, higher HLA-DR expression on CD14+ monocytes and a lower proportion of CD25+Foxp3+ in CD4+ T lymphocytes were observed in the patients in the HVHF group. CONCLUSIONS: Early application of HVHF benefits patients with severe burns, especially for those with a greater burn area (≥ 80% TBSA), decreasing the incidence of sepsis and mortality. This effect may be attributed to its early clearance of inflammatory mediators and the recovery of the patient's immune status. TRIAL REGISTRATION: Chinese Clinical Trial Register, ChiCTR-TRC-12002616 . Registered on 24 October 2012.

[pH-sensitive micelles loaded paclitaxel using carboxymethyl chitosan-palmitic acid mediated by cRGD].

cRGD-carboxymethyl chitosan-palmitic acid (cRGD-CMCh-PA) was synthesized and a pH- sensitive paclitaxel-loaded cRGD-CMCh-PA micelles（PTX-cRGD-CMCh-PA） was prepared with the film dispersion method; related substances were characterized by FT-IR and (1)H NMR. PTX-cRGD-CMCh-PA micelles were studied with the particle size distribution, zeta potential, morphology and release behavior in vitro was investigated by the method of equilibrium dialysis. In vitro cytotoxicity of different formulations on A549 cells was tested by MTT assay. The uptake process of micelles was explored using confocal microscopy and a live cell station was used to observe the dynamic phagocytosis. The subcutaneous and orthotropic tumor models were built to study the distribution of Di R-labeled micelles by near-infrared fluorescence（NIR） imaging system. The FT-IR spectra and (1)H NMR spectra confirmed the successful conjugation of cRGD-CMCh-PA polymer and the degree of carboxymethyl and the palmitic acid grafted on chitosan were 45.0% and 15.0%. PTX-cRGD-CMCh-PA micelles were prepared with particle size of（162.9 ± 1.5） nm, zeta potential of +26.3 m V and encapsulation efficiency and the drug loading of 99.67% and 28.5%, respectively. The micelles released slowly in pH 7.4 whose release curves were accorded with the Higuchi equation; they had an initial burst effect in second hours and showed a pH sensitive release behavior in pH 5.3. The IC(50) of PXT-CMCh-PA and PTX-cRGD-CMCh-PA were 2.077 µg·mL(-1) and 0.876 µg·mL(-1), respectively. The cells uptake process of micelles in A549 cells revealed that the micelles were mainly co-located with lysosome and PTX-cRGD-CMCh- PA showed much better targeting effect. The NIR fluorescence imaging results showed that the micelles had a good targeting effect on both subcutaneous and orthotropic tumors. In this study, a novel copolymer cRGD- CMCh-PA was synthesized with a sustained and pH-dependent drug release activity which would potentially become a new carrier for hydrophobic drugs.

BL02, a phage against carbapenem- and polymyxin-B resistant Klebsiella pneumoniae, isolated from sewage: A preclinical study.

The emergence of Carbapenem-resistant Klebsiella pneumoniae (CRKP) represents a threat to public health. Polymyxin-B is generally considered a last-resort antibiotic. In this study, we isolated a carbapenem- and polymyxin-B resistant K. pneumoniae phage BL02 for the first time in Southwestern China and evaluated its biological characteristics and whole-genome sequence. Polymyxin-B resistant K. pneumoniae, (CK02), was isolated from the blood of a male with severe septic shock, and phage BL02 was screened and purified from the hospital sewage. BL02 could lyse 40 out of 46 CRKP isolates (86.96%) and has high activity in the pH range of 6-10 and the temperature range of 4-55 °C. The latency period of BL02 was about 10 min and the lysis period was about 50 min. The genome results showed that BL02 was a linear dsDNA with a total length of 175,595 bp and a GC content of 41.83%. A total of 275 ORFs were predicted and no tRNA, rRNA, drug resistance genes, or virulence genes were found in the genome. Phylogenetic analysis showed that BL02 belongs to the family Straboviridae. Treatment of infected mice with two antibiotics (tigecycline or ceftazidime/avibactam) resulted in 7-day survival rates of 28.57% and 42.86%, respectively. In contrast, the survival rate of mice in the single-dose BL02-treated group was 71.43%. In summary, this preclinical study isolated a phage capable of lysing polymyxin-B resistant K. pneumoniae and validated its safety and efficacy in an in vivo model, which provides a reference for further research on controlling MDR pathogens.

Contrast-enhanced ultrasound of a traumatic neuroma of the extrahepatic bile duct: A case report and review of literature.

BACKGROUND: Traumatic neuromas result from nerve injury after trauma or surgery but rarely occur in the bile duct. However, it is challenging to diagnose traumatic neuromas correctly preoperatively. Although some previous reports have described the imaging features of traumatic neuroma in the bile duct, no features of traumatic neuromas in the bile duct have been identified by using contrast-enhanced ultrasound (CEUS) imaging before. CASE SUMMARY: A 55-year-old male patient presented to our hospital with a 3-mo history of abdominal distension and anorexia and history of cholecystectomy 4 years ago. Grayscale ultrasound demonstrated mild to moderate intrahepatic bile duct dilatation. Meanwhile, a hyperechoic nodule was found in the upper extrahepatic bile duct. The lesion approximately 0.8 cm × 0.6 cm with a regular shape and clear margins. The nodule of the bile duct showed slight hyperenhancement in the arterial phase and isoenhancement in the venous phase on CEUS. Laboratory tests showed that alanine aminotransferase and aspartate aminotransferase were increased significantly, while the tumor marker carbohydrate antigen 19-9 was increased slightly. Then, hilar bile duct resection and end-to-end bile ductal anastomosis were performed. The histological examination revealed traumatic neuroma of the extrahepatic bile duct. The patient had an uneventful recovery after surgery. CONCLUSION: The current report will help enhance the current knowledge regarding identifying traumatic neuromas by CEUS imaging and review the related literature.

In vitro maturation and migration of immature dendritic cells after chemokine receptor 7 transfection.

Dendritic cells are specialized antigen-presenting cells that regulate immunity and tolerance. Chemokine receptor 7 (CCR7), which is expressed by mature dendritic cells, mediates the migration of the cells to secondary lymphoid organs and thus regulates immune responses. It has been demonstrated that immature dendritic cells can induce immune tolerance, but they do not express CCR7 and cannot migrate to secondary lymphoid organs. We transfected immature dendritic cells with a recombinant adenovirus carrying the CCR7 gene to obtain immature dendritic cells with the ability to migrate. The maturity of the cells was monitored by scanning electron microscopy and flow cytometry. In addition, we assessed the ability of cells to migrate and the function of the cells using in vitro chemotactic and mixed leukocyte reaction assays. The results showed that immature dendritic cells became semi-mature, exhibiting a mild upregulation of co-stimulatory molecular expression and a few dendritic processes. Immunofluorescence assay and Western blotting indicated that CCR7 protein expression increased significantly in immature dendritic cells following CCR7 gene transfection. The in vitro chemotactic assay showed a significantly enhanced ability to migrate in response to CCL19 following CCR7 gene transfection. Moreover, transfected cells showed an enhanced ability to stimulate allogeneic T cell proliferation in vitro, but their ability was significantly weaker than that of mature dendritic cells. Interleukin-10 inhibited the differentiation and maturation of immature dendritic cells. It is concluded that, following CCR7 gene transfection, immature dendritic cells exhibit an enhanced ability to migrate and some of the characteristics of mature cells. Thus, these cells are of potential clinical significance in studies of immune tolerance induction during skin grafting after severe burns.

Induction of heat shock protein 70 by sodium arsenite attenuates burn-induced intestinal injury in severe burned rats.

The present study was designed to assess the effects of induced heat shock protein 70 (HSP70) on intestinal injury after severe burn. Wistar rats were randomly divided into four groups: control group, burn group (B group), sodium arsenite pretreatment group (SA group), and sodium arsenite+quercetin pretreatment group (SA+Qu group). Plasma endotoxin and d-lactic acid content were determined at 3, 6, 12, 24, and 48h after severe burn. Samples of small intestine were obtained for histologic assessment of intestinal mucosal injury and the expression of HSP70 was assayed by Western blot. Apoptosis of the intestinal epithelial cells was examined by the TUNEL method. Results showed that SA pretreatment significantly increased expression of HSP70 in the small intestine. SA pretreatment attenuated the burn-induced increase in plasma endotoxin and d-lactic acid content, intestinal injury scores and the percentage of apoptotic intestinal epithelial cells. Co-administration of quercetin with SA abolished the SA-induced HSP70 over-expression and the beneficial effects of SA. Our findings suggest increasing expression of HSP70 induced by SA pretreatment attenuates burn-induced intestinal injury apparently by preventing apoptosis.

[Percutaneous dynamic release in stress position by acupotomy in treating severe scapulohumeral periarthritis].

OBJECTIVE: To investigate the clinical efficacy of acupotomy stress position percutaneous dynamic release for severe shoulder periarthritis. METHODS: From April 2012 to August 2016, 160 patients with severe shoulder periarthritis were randomly divided into treatment group and control group. Among them, 80 patients in treatment group were treated with acupotomy stress position percutaneous dynamic release including 32 males and 48 females with an average of(52.47±9.04)years old ranging from 40 to 74 years old;the courses of disease was(20.72±9.55)months on average. The other 80 patients in control group were treated with simple joint loosening according to Maitland technique in grade III-IV therapy, once a day, 15 to 20 min each time, and 10 d for 1 course, for a total of 2 courses, including 33 males and 47 females with an average of (53.19±10.18) years old ranging from 42 to 75 years old; the average course of disease was (21.98 ±8.99) months. After operation, the shoulder muscles training and shoulder joint activity training were routinely conducted, the treatment lasted for 3 weeks. The visual analogue scale(VAS) and Constant-Murley shoulder function score were observed and compared between the two groups before treatment and 3 weeks, 3, 6 months after treatment. RESULTS: The VAS scores of the treatment group at 3 weeks, 3 and 6 months after treatment were all lower than those of the control group(P<0.05). The shoulder joint function Constant-Murley scores of the treatment group at 3 weeks, 3 and 6 months after treatment were higher than those of the control group (P<0.05); the result was excellent in 59 cases, good in 18 cases, fair in 3 cases in the treatment group; excellent in 15 cases, good in 31 cases, fair in 23 cases, poor in 11 cases in the control group, and the difference between the two groups was statistically significant(P<0.01). CONCLUSIONS: Treatment of severe shoulder periarthritis with acupotomy stress position percutaneous dynamic release can obviously improve the shoulder joint function and pain, according to the different parts of the shoulder joint pain and function limitation, the corresponding shoulder stress and body position should be designed and maintained during the treatment process, and the angle of stress position gradually increased by loosening the adhesion, which is the key to ensure the curative effect.

Glutamine with probiotics attenuates intestinal inflammation and oxidative stress in a rat burn injury model through altered iNOS gene aberrant methylation.

Severe burns may lead to intestinal inflammation and oxidative stress resulting in intestinal barrier damage and gut dysfunction. In the management of severe burns, therapies are needed to attenuate whole-body inflammatory responses and control the burden of oxidative stress. In this study, we evaluated the effects of oral glutamine (Gln) with probiotics on burn-induced intestinal inflammation and oxidative stress using a Wistar rat burn injury model. We then explored potential molecular mechanisms for the effects of glutamine and probiotics on intestinal tissue inflammation and oxidative stress. We found that glutamine and probiotics together significantly inhibited nitric oxide (NO) content; reduced levels of the inflammatory factors TNF-α, IL-6, and IL-8; and altered expression of oxidative stress factors including reactive oxygen species and superoxide dismutase. We found that the apoptotic proportion of intestinal epithelial cells in severely burned subjects was notably decreased following treatment with glutamine plus probiotics. We also found that glutamine and probiotics given together markedly reduced NO content by down-regulating the expression of iNOS in blood and intestinal tissue. These findings indicate that regulation of the iNOS gene plays a pivotal role in inflammation and oxidative stress in the response to severe burns in the Wistar rat. We then further investigated the mechanism by which combined therapy with glutamine and probiotics might reduce expression of iNOS and found that this treatment resulted in increased methylation of the iNOS gene. The methylation level of the iNOS gene was found to be regulated via differential expression of DNMT1 and Tet1. Collectively, our results suggest that combined therapy with glutamine and probiotics can markedly reduce the synthesis of NO, suppressing intestinal inflammation and oxidative stress in the Wistar rat burn injury model.

Low-density lipoprotein-coupled micelles with reduction and pH dual sensitivity for intelligent co-delivery of paclitaxel and siRNA to breast tumor.

Multidrug resistance (MDR) is a major obstacle for the clinical therapy of malignant human cancers. The discovery of RNA interference provides efficient gene silencing within tumor cells for reversing MDR. In this study, a new "binary polymer" low-density lipoprotein-N-succinyl chitosan-cystamine-urocanic acid (LDL-NSC-SS-UA) with dual pH/redox sensitivity and targeting effect was synthesized for the co-delivery of breast cancer resistance protein small interfering RNA (siRNA) and paclitaxel (PTX). In vivo, the co-delivering micelles can accumulate in tumor tissue via the enhanced permeability and retention effect and the specific recognition and combination of LDL and LDL receptor, which is overexpressed on the surface of tumor cell membranes. The siRNA-PTX-loaded micelles inhibited gene and drug release under physiological conditions while promoting fast release in an acid microenvironment or in the presence of glutathione. The micelles escaped from the lysosome through the proton sponge effect. Additionally, the micelles exhibited superior antitumor activity and downregulated the protein and mRNA expression levels of breast cancer resistance protein in MCF-7/Taxol cells. The biodistribution and antitumor studies proved that the siRNA-PTX-loaded micelles possessed prolonged circulation time with a remarkable tumor-targeting effect and effectively inhibited tumor growth. Therefore, the novel dual pH/redox-sensitive polymers co-delivering siRNA and PTX with excellent biocompatibility and effective reversal of MDR demonstrate a considerable potential in cancer therapy.

Multifunctional nanoparticles co-delivering EZH2 siRNA and etoposide for synergistic therapy of orthotopic non-small-cell lung tumor.

Malignant proliferation and metastasis in non-small cell lung carcinoma (NSCLC) are great challenges for effective clinical treatment through conventional chemotherapy. The combinational therapy strategy of RNA interfering (RNAi) technology and chemotherapeutic agents have been reported to be promising for effective cancer therapy. In this study, based on multifunctional nanoparticles (NPs), the simultaneous delivery of etoposide (ETP) and anti-Enhancer of Zeste Homologue 2 (EZH2) siRNA for the effective treatment of orthotopic lung tumor was achieved. The NPs exhibited pH/redox dual sensitivity verified by particle size changes, morphological changes, and in vitro release of drugs. Confocal microscopy analysis confirmed that the NPs exhibited endosomal escape property and on-demand intracellular drug release behavior, which can protect siRNA from degradation and facilitate the chemotherapeutic effect respectively. In vitro tumor cell motility study demonstrated that EZH2 siRNA loaded in NPs can decrease the migration and invasion capabilities of tumor cells by downregulating the expression of EZH2 mRNA and protein. In particular, an antiproliferation study revealed that the co-delivery of siRNA and ETP in the multifunctional NPs can induce a synergistic therapeutic effect on NSCLC. In vivo targeting evaluation showed that cRGDyC-PEG modification on NPs exhibited a low distribution in normal organs and an obvious accumulation in orthotopic lung tumor. Furthermore, targeted NPs co-delivering siRNA and ETP showed superior inhibition on tumor growth and metastasis and produced minimal systemic toxicity. These findings indicated that multifunctional NPs can be utilized as a co-delivery system, and that the combination of EZH2 siRNA and ETP can effectively treat NSCLC.

Stepwise pH-responsive nanoparticles for enhanced cellular uptake and on-demand intracellular release of doxorubicin.

Physicochemical properties, including particle size, zeta potential, and drug release behavior, affect targeting efficiency, cellular uptake, and antitumor effect of nanocarriers in a formulated drug-delivery system. In this study, a novel stepwise pH-responsive nanodrug delivery system was developed to efficiently deliver and significantly promote the therapeutic effect of doxorubicin (DOX). The system comprised dimethylmaleic acid-chitosan-urocanic acid and elicited stepwise responses to extracellular and intracellular pH. The nanoparticles (NPs), which possessed negative surface charge under physiological conditions and an appropriate nanosize, exhibited advantageous stability during blood circulation and enhanced accumulation in tumor sites via enhanced permeability and retention effect. The tumor cellular uptake of DOX-loaded NPs was significantly promoted by the first-step pH response, wherein surface charge reversion of NPs from negative to positive was triggered by the slightly acidic tumor extracellular environment. After internalization into tumor cells, the second-step pH response in endo/lysosome acidic environment elicited the on-demand intracellular release of DOX from NPs, thereby increasing cytotoxicity against tumor cells. Furthermore, stepwise pH-responsive NPs showed enhanced antiproliferation effect and reduced systemic side effect in vivo. Hence, the stepwise pH-responsive NPs provide a promising strategy for efficient delivery of antitumor agents.

Distinctive polymer micelle designed for siRNA delivery and reversal of MDR1 gene-dependent multidrug resistance.

P-glycoprotein (P-gp) plays an importantrole in multidrug resistance (MDR), proved to be one of the major obstacles in cancer chemotherapy. Cationic polymers could specifically deliver siRNA to tumor cells and thus reverse MDR by the downregulation of P-gp. In this study, a triblock copolymer micelle was prepared based on the polymer of N-succinyl-chitosan-poly-l-lysine-palmitic acid (NSC-PLL-PA) to deliver siRNA-P-gp (siRNA-micelle) or doxorubicin (Dox-micelle). The resulting micelle exhibited an efficient binding ability for siRNA and high encapsulation efficiency for Dox, with an average particle size of ∼170 nm. siRNA-micelle and Dox-micellewere instable at low pH, thereby enhancing tumor accumulation and intracellular release of the encapsulated siRNA and Dox. siRNA-micelle micelles could enhance the knockdown efficacy of siRNA by improving the transfection efficiency, downregulating P-gp expression, and passing the drug efflux transporters, thereby improving the therapeutic effects of Dox-micelle. However, P-gp could transfer from HepG2/ADM to HepG2 cells independent of the expression of mdr1, and the acquired resistance could permit tumor cells to survive and develop intrinsic P-gp-mediated resistance, thereby limiting the desired efficiency of chemotherapeutics. This study demonstrated the effectiveness of siRNA-micelle for tumor-targeted delivery, MDR reversal, and provided an effective strategy for the treatment of cancers that develop MDR. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2093-2106, 2017.

Binary-copolymer system base on low-density lipoprotein-coupled N-succinyl chitosan lipoic acid micelles for co-delivery MDR1 siRNA and paclitaxel, enhances antitumor effects via reducing drug.

The development of effective and stable carriers of small interfering RNA (siRNA) is important for treating cancer with multidrug resistance (MDR). We developed a new gene and drug co-delivery system and checked its characteristics. Low-density lipoprotein (LDL) was coupled with N-succinyl chitosan (NSC) Lipoic acid (LA) micelles and co-delivered MDR1 siRNA and paclitaxel (PTX-siRNA/LDL-NSC-LA) to enhance antitumor effects by silencing the MDR gene of tumors (Li et al., Adv Mater 2014;26:8217-8224). In our study, we developed a new type of containing paclitaxel-loaded micelles and siRNA-loaded LDL nanoparticle. This "binary polymer" is pH and reduction dual-sensitive core-crosslinked micelles. PTX-siRNA/LDL-NSC-LA had an average particle size of (171.6 ± 6.42) nm, entrapment efficiency of (93.92 ± 1.06) %, and drug-loading amount of (12.35% ± 0.87) %. In vitro, MCF-7 cells, high expressed LDL receptor, were more sensitive to this delivery system than to taxol® and cell activity was inhibited significantly. Fluorescence microscopy showed that PTX-siRNA/LDL-NSC-LA was uptaken very conveniently and played a key role in antitumor activity. PTX-siRNA/LDL-NSC-LA protected the siRNA from degradation by macrophage phagocytosis and evidently down-regulated the level of mdr1 mRNA as well as the expression of P-gp. We tested the target ability of PTX-siRNA/LDL-NSC-LA in vivo in tumor-bearing nude mice. Results showed that this system could directly deliver siRNA and PTX to cancer cells. Thus, new co-delivering siRNA and antitumor drugs should be explored for solving MDR in cancer. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1114-1125, 2017.

Tumor microenvironment-responsive micelles for pinpointed intracellular release of doxorubicin and enhanced anti-cancer efficiency.

Internal stimuli, such as intracellular lysosomal pH, enzyme, redox and reduction, can be applied to improve biological specificity of chemotherapeutic drugs for cancer therapy. Thus, functionalized copolymers based on their response to specific microenvironment of tumor regions have been designed as smart drug vesicles for enhanced anti-cancer efficiency and reduced side effects. Herein, we reported dually pH/reduction-responsive novel micelles based on self-assembly of carboxymethyl chitosan-cysteamine-N-acetyl histidine (CMCH-SS-NA) and doxorubicin (DOX). The tailor-made dually responsive micelles demonstrated favorable stability in normal physiological environment and triggered rapid drug release in acidic and/or reduction environment. Additionally, the nanocarriers responded to the intracellular environment in an ultra-fast manner within several minutes, which led to the pinpointed release of DOX in tumor cells effectively and ensured higher DOX concentrations within tumor areas with the aid of targeted delivery, thereby leading to enhanced tumor ablation. Thus, this approach with sharp drug release behavior represented a versatile strategy to provide a promising paradigm for cancer therapy.

Liposomes coated with N-trimethyl chitosan to improve the absorption of harmine in vivo and in vitro.

In this study, harmine liposomes (HM-lip) were prepared through the thin-film hydration-pH-gradient method and then coated with N-trimethyl chitosan (TMC). Particle size, zeta potential, entrapment efficiency, and in vitro release of HM-lip and TMC-coated harmine liposomes (TMC-HM-lip) were also determined. Sprague Dawley rats were further used to investigate the pharmacokinetics in vivo. Retention behavior in mouse gastrointestinal tract (GIT) was studied through high-performance liquid chromatography and near-infrared imaging. Degradation was further evaluated through incubation with Caco-2 cell homogenates, and a Caco-2 monolayer cell model was used to investigate the uptake and transport of drugs. HM-lip and TMC-HM-lip with particle size of 150-170 nm, an entrapment efficiency of about 81%, and a zeta potential of negative and positive, respectively, were prepared. The release of HM from HM-lip and TMC-HM-lip was slower than that from HM solution and was sensitive to pH. TMC-HM-lip exhibited higher oral bioavailability and had prolonged retention time in GIT. HM-lip and TMC-HM-lip could also protect HM against degradation in Caco-2 cell homogenates. The uptake amount of TMC-HM-lip was higher than that of HM and HM-lip. TMC-HM-lip further demonstrated higher apparent permeability coefficient (P(app)) from the apical to the basolateral side than HM and HM-lip because of its higher uptake and capability to open tight junctions in the cell monolayers. TMC-HM-lip can prolong the retention time in the GIT, protect HM against enzyme degradation, and improve transport across Caco-2 cell monolayers, thus enhancing the oral bioavailability of HM.

Novel polymer micelle mediated co-delivery of doxorubicin and P-glycoprotein siRNA for reversal of multidrug resistance and synergistic tumor therapy.

Co-delivery of chemotherapeutics and siRNA with different mechanisms in a single system is a promising strategy for effective cancer therapy with synergistic effects. In this study, a triblock copolymer micelle was prepared based on the polymer of N-succinyl chitosan-poly-L-lysine-palmitic acid (NSC-PLL-PA) to co-deliver doxorubicin (Dox) and siRNA-P-glycoprotein (P-gp) (Dox-siRNA-micelle). Dox-siRNA-micelle was unstable in pH 5.3 medium than in pH 7.4 medium, which corresponded with the in vitro rapid release of Dox and siRNA in acidic environments. The antitumor efficacy of Dox-siRNA-micelle in vitro significantly increased, especially in HepG2/ADM cells, which was due to the downregulation of P-gp. Moreover, almost all the Dox-siRNA-micelles accumulated in the tumor region beyond 24 h post-injection, and the co-delivery system significantly inhibited tumor growth with synergistic effects in vivo. This study demonstrated the effectiveness of Dox-siRNA-micelles in tumor-targeting and MDR reversal, and provided a promising strategy to develop a co-delivery system with synergistic effects for combined cancer therapy.

Enhanced Cellular Internalization and On-Demand Intracellular Release of Doxorubicin by Stepwise pH-/Reduction-Responsive Nanoparticles.

The efficient delivery of antitumor agents to tumor sites faces numerous obstacles, such as poor cellular uptake and slow intracellular drug release. In this regard, smart nanoparticles (NPs) that respond to the unique microenvironment of tumor tissues have been widely used for drug delivery. In this study, novel charge-reversal and reduction-responsive histidine-grafted chitosan-lipoic acid NPs (HCSL-NPs) were selected for efficient therapy of breast cancer by enhancing cell internalization and intracellular pH- and reduction-triggered doxorubicin (DOX) release. The surface charge of HCSL-NPs presented as negative at physiological pH and reversed to positive at the extracellular and intracellular pH of the tumor. In vitro release investigation revealed that DOX/HCSL-NPs demonstrated a sustained drug release under the physiological condition, whereas rapid DOX release was triggered by both endolysosome pH and high-concentration reducing glutathione (GSH). These NPs exhibited enhanced internalization at extracellular pH, rapid intracellular drug release, and improved cytotoxicity against 4T1 cells in vitro. Excellent tumor penetrating efficacy was also found in 4T1 tumor spheroids and solid tumor slices. In vivo experiments demonstrated that HCSL-NPs exhibited excellent tumor-targeting ability in tumor tissues as well as excellent antitumor efficacy and low systemic toxicity in breast tumor-bearing BALB/c mice. These results indicated that the novel charge-reversal and reduction-responsive HCSL-NPs have great potential for targeted and efficient delivery of chemotherapeutic drugs in cancer treatments.

[Expression of heat shock protein 70 in intestinal mucosa during the early stage after severe burns and its significance].

OBJECTIVE: To study the expression of heat shock protein 70 (HSP70) in intestinal mucosa during the early stage after severe burn injury and its significance. METHODS: With a model of 30% total body surface area (TBSA) full-thickness burned rats, the expression and distribution of HSP70 and heat shock factor-1 (HSF1) in intestinal mucosal were determined by reverse transcription-polymerase chain reaction (RT-PCR), Western blot and immunohistochemistry at 3, 6, 12, 24 and 48 hours postburn. RESULTS: The expression of HSP70 mRNA and protein in intestinal mucosa increased markedly at 3 hours after severe burns, peaked at 6 and 12 hours, and lasted for 48 hours postburn (all P<0.01). Following a slight decline at 3 hours postburn, the expression of HSF1 increased gradually, and reached a highest level at 48 hours postburn (all P<0.01). CONCLUSION: The expression of HSP70 and HSF1 markedly increase in intestinal mucosa following severe burn injury. It is suggested that the self-protective mechanism of cells might explain the increase of HSP70 expression.

CD147 monoclonal antibody mediated by chitosan nanoparticles loaded with α-hederin enhances antineoplastic activity and cellular uptake in liver cancer cells.

An antibody that specifically interacts with an antigen could be applied to an active targeting delivery system. In this study, CD147 antibody was coupled with α-hed chitosan nanoparticles (α-Hed-CS-NPs). α-Hed-CS-CD147-NPs were round and spherical in shape, with an average particle size of 148.23 ± 1.75 nm. The half-maximum inhibiting concentration (IC50) of α-Hed-CS-CD147-NPs in human liver cancer cell lines HepG2 and SMMC-7721 was lower than that of free α-Hed and α-Hed-CS-NPs. α-Hed-induced cell death was mainly triggered by apoptosis. The increase in intracellular accumulation of α-Hed-CS-CD147-NPs was also related to CD147-mediated internalization through the Caveolae-dependent pathway and lysosomal escape. The higher targeting antitumor efficacy of α-Hed-CS-CD147-NPs than that α-Hed-CS-NPs was attributed to its stronger fluorescence intensity in the tumor site in nude mice.

Systemic delivery of micelles loading with paclitaxel using N-succinyl-palmitoyl-chitosan decorated with cRGDyK peptide to inhibit non-small-cell lung cancer.

This study aimed to prepare efficient cRGDyK peptide-decorated micelles for the targeted therapy of non-small-cell lung cancer (NSCLC). An amphiphilic copolymer N-succinyl-palmitoyl-chitosan (SPCS) was synthesized and characterized. cRGDyK peptide is a ligand that can target tumors via specific binding integrin receptor overexpressed on tumor neovascularization and cells. cRGDyK-functionalized SPCS micelles loaded with paclitaxel (PTX/cRGDyK-SPCS) were prepared by film dispersion method and then characterized according to morphology, size, and zeta potential. PTX/cRGDyK-SPCS micelles presented pH-triggered drug release behavior under acidic conditions. The accumulation of micelles detected by laser confocal fluorescence microscopy and flow cytometry showed that cRGDyK-SPCS micelles were easily taken up by A549 cells marked with the luciferase gene (luc-A549). Meanwhile, co-localization of the micelles and lysosomes was recorded dynamically using a live cell station. MTT assays and cell apoptosis studies revealed that cell viability was significantly inhibited by PTX/cRGDyK-SPCS micelles. More importantly, in vivo animal studies showed that cRGDyK-SPCS micelles mainly accumulated in the orthotopic tumor site. PTX/cRGDyK-SPCS micelles exhibited better anti-tumor activity in subcutaneous and orthotopic lung tumors compared with PTX/SPCS micelles and Taxol(®). These results suggested that PTX/cRGDyK-SPCS micelles had better cancer targeting capacity and superior anti-tumor efficacy. Thus, these micelles have great potential as novel carriers in delivering anti-tumor drugs.