Biodegradable Cationic Polycarbonates as Vaccine Adjuvants.

In this study, biodegradable cationic polycarbonate and polylactide block copolymers were synthesized and successfully used as novel vaccine adjuvants to provide enhanced anticancer immunity. The polymers formed nanoparticles with the model vaccine, ovalbumin (OVA), and the immunostimulant toll-like receptor 3 agonist poly(I:C) (a synthetic analog of the double-stranded RNA). Higher uptake of poly(I:C) by the bone marrow-derived dendritic cells and macrophages and OVA by dendritic cells was observed when delivered using the polymer adjuvant. In vivo experiments showed that these nanoparticles remained longer in the subcutaneous injection site as compared to OVA alone and led to higher production of anti-OVA specific antibodies with prolonged immunostimulation. When OVA was combined with poly(I:C) that was either co-entrapped in the same particles or as separate particles, a comparable level of anti-OVA IgG1 antibodies and interleukin-6 (IL-6) was produced in mouse blood plasma, and a similar level of cytotoxic T lymphocyte (CTL) response in mice was stimulated as compared to OVA/Alum particles. Furthermore, tumor rejection in the mice that were vaccinated for 9 months with the formulations containing the polymer adjuvant was stronger than the other treatment groups without the polymer. Notably, the cationic polycarbonates were not associated with any adverse in vivo effects. Thus, these biodegradable polymers may be promising substitutes for aluminum-based adjuvants in vaccine formulations.

Subcutaneous vaccination using injectable biodegradable hydrogels for long-term immune response.

Prolonged vaccine release enables gradual immunostimulation, providing long-term immunity. Herein, Vitamin E-PEG-Vitamin E triblock 'ABA' hydrogel, which is formed through physical cross-linking of flower-shaped micelles and can reside in vivo for >17 weeks, was employed for delivery of cancer preventive vaccines to provide sustained anticancer immunity. Mice vaccinated with hydrogel formulations produced a significantly higher quantity of antibodies compared to solution formulations. OVA was used to study EG.7-OVA tumor rejection in vaccinated mice. Among all formulations, OVA-loaded hydrogel containing aluminum-based adjuvant had the best therapeutic outcome, and only 2/10 mice developed solid tumors with significantly smaller tumor size. Moreover, no adverse effect on liver and kidney was detected with the hydrogel formulation. In a lymphoma metastasis mouse model, vaccination with the OVA-loaded hydrogel and adjuvant resulted in increased survival (66.7%) compared to other formulations (12.5-50%) over 100 days. This hydrogel is a promising formulation for sustained delivery of vaccines.

Degradable antimicrobial polycarbonates with unexpected activity and selectivity for treating multidrug-resistant Klebsiella pneumoniae lung infection in mice.

Multidrug resistant (MDR) Klebsiella pneumoniae is a major cause of healthcare-associated infections around the world, with attendant high rates of morbidity and mortality. Progressive reduction in potency of antibiotics capable of treating MDR K. pneumoniae infections - including lung infection - as a consequence of escalating drug resistance provides the motivation to develop drug candidates targeting MDR K. pneumoniae. We recently reported degradable broad-spectrum antimicrobial guanidinium-functionalized polycarbonates with unique antimicrobial mechanism - membrane translocation followed by precipitation of cytosolic materials. These polymers exhibited high potency against bacteria with negligible toxicity. The polymer with ethyl spacer between the quanidinium group and the polymer backbone (pEt_20) showed excellent in vivo efficacy for treating MDR K. pneumoniae-caused peritonitis in mice. In this study, the structures of the polymers were optimized for the treatment of MDR Klebsiella pneumoniae lung infection. Specifically, in vitro antimicrobial activity and selectivity of guanidinium-functionalized polycarbonates containing the same number of guanidinium groups but of a shorter chain length and a structural analogue containing a thiouronium moiety as the pendent cationic group were evaluated. The polymers with optimal compositions and varying hydrophobicity were assessed against 25 clinically isolated K. pneumonia strains for antimicrobial activity and killing kinetics. The results showed that the polymers killed the bacteria more efficiently than clinically used antibiotics, and repeated use of the polymers did not cause drug resistance in K. pneumonia. Particularly, the polymer with butyl spacer (pBut_20) self-assembled into micelles at high concentrations, where the hydrophobic component was shielded in the micellar core, preventing interacting with mammalian cells. A subtle change in the hydrophobicity increased the antimicrobial activity while reducing in vivo toxicity. The in vivo efficacy studies showed that pBut_20 alleviated K. pneumonia lung infection without inducing damage to major organs. Taken together, pBut_20 is promising for treating MDR Klebsiella pneumoniae lung infection in vivo. STATEMENT OF SIGNIFICANCE: Multidrug resistant (MDR) Klebsiella pneumoniae is a major cause of healthcare-associated infections, with attendant high rates of morbidity and mortality. The progressive reduction in antibiotics capable of treating MDR K. pneumoniae infections - including lung infection - as a consequence of escalating drug resistance rates provides the motivation to develop drug candidates. In this study, we report a degradable guanidinium-functionalized polycarbonate with unexpected antimicrobial activity and selectivity towards MDR Klebsiella pneumoniae. A subtle change in polymer hydrophobicity increases antimicrobial activity while reducing in vivo toxicity due to self-assembly at high concentrations. The polymer with optimal composition alleviates Klebsiella pneumonia lung infection without inducing damage to major organs. The polymer is promising for treating MDR Klebsiella pneumoniae lung infection in vivo.

Dihydroartemisinin induces apoptosis and inhibits proliferation, migration, and invasion in epithelial ovarian cancer via inhibition of the hedgehog signaling pathway.

Dihydroartemisinin (DHA), the primary of artemisinin extracted from the traditional Chinese medicine Artemisia annua, has been used in malaria treatment for a long time. Recently, many studies have indicated that, in addition to antimalarial effects, DHA also exhibits anticancer activity in certain types of neoplasms, including ovarian cancer. However, the precise anti-ovarian cancer mechanism of DHA is still unclear. Abnormal activation of the hedgehog (Hh) pathway is closely related to tumorigenesis and progression of ovarian cancer. We performed this study to elucidate the effects of DHA on the biological behavior of ovarian cancer cells and to determine its effects on the Hh signaling pathway. CCK8 assays and flow cytometry were used to evaluate the effects of DHA on cell viability and apoptosis in both ovarian cancer cells and HOSEPICs (human ovarian surface epithelial cells) in response to DHA treatment. Transwell membrane chambers were used to analyze the effects of DHA on the migration and invasion of epithelial ovarian cancer cells following treatment with DHA. The impact of DHA on Hh signaling was analyzed by RT-qPCR and Western blot. DHA significantly inhibited proliferation, migration, and invasion of ovarian cancer cells, and induced apoptosis in vitro. In contrast, DHA had few effects on cell proliferation and apoptosis in HOSEPICs. DHA inhibited the hedgehog signaling pathway. Furthermore, DHA inhibited purmorphamine (Hh signaling pathway agonist)-induced cell proliferation, cell migration, and cell invasion and the inhibition of apoptosis. Importantly, DHA enhanced GANT61 (hedgehog signaling pathway inhibitor)-induced apoptosis and the inhibition of cell viability, migratory capacity, and invasive ability. This study demonstrates that DHA inhibits cell viability, migration, and invasion, as well as induces apoptosis in epithelial ovarian cancer through suppression of the Hh signaling pathway.

A macromolecular approach to eradicate multidrug resistant bacterial infections while mitigating drug resistance onset.

Polymyxins remain the last line treatment for multidrug-resistant (MDR) infections. As polymyxins resistance emerges, there is an urgent need to develop effective antimicrobial agents capable of mitigating MDR. Here, we report biodegradable guanidinium-functionalized polycarbonates with a distinctive mechanism that does not induce drug resistance. Unlike conventional antibiotics, repeated use of the polymers does not lead to drug resistance. Transcriptomic analysis of bacteria further supports development of resistance to antibiotics but not to the macromolecules after 30 treatments. Importantly, high in vivo treatment efficacy of the macromolecules is achieved in MDR A. baumannii-, E. coli-, K. pneumoniae-, methicillin-resistant S. aureus-, cecal ligation and puncture-induced polymicrobial peritonitis, and P. aeruginosa lung infection mouse models while remaining non-toxic (e.g., therapeutic index-ED50/LD50: 1473 for A. baumannii infection). These biodegradable synthetic macromolecules have been demonstrated to have broad spectrum in vivo antimicrobial activity, and have excellent potential as systemic antimicrobials against MDR infections.

Transcervical incision of septa: 447 cases.

BACKGROUND: Although uterine septum does not cause infertility, it may lead to recurrent abortion, preterm delivery, and premature rupture of membrane in over 25% of patients. The aim of this study was to evaluate feasibility and clinical value of hysteroscopic bipolar electric vaporization technique (Versapoint Bipolar Electrosurgical System) used in transcervical incision of septa (TCIS) in an outpatient setting. METHODS: Retrospectively, 447 cases of hysteroscopic TCIS were analyzed. Operative time, blood loss, consumption of uterus distension medium, and period of postoperative hospital stay were compared between outpatients and inpatients. Feasibility of outpatient TCIS using bipolar electric vaporization system under analgesia and without anesthesia was investigated. All hysteroscopic procedures were performed after review and approval by institutional ethical committee. Stata 8.0 software was used for statistical analysis, and t test and chi (2) test were used to evaluate association among numerical and categorical variables. p < 0.05 indicated statistically significant difference. RESULTS: The study included 121 inpatients (27.1%) and 326 outpatients (72.9%). Three hundred sixty-two cases (80.98%) were under only pethidine analgesia and 420 cases (93.96%) under local infiltration anaesthesia or analgesia. Of 447 cases of TCIS, 433 (96.87%) were accomplished under intravenous, local infiltration anaesthesia or pethidine analgesia. In all TCIS, 421 cases (94.18%) were carried out with mechanical microscissors and bipolar electric vaporization incision. No significant difference was identified between inpatients and outpatients in terms of operative time, blood loss, or consumption of uterus distension medium (p > 0.05). However, period of postoperative hospital stay was significantly shorter in outpatient TCIS than in inpatient TCIS by an average of 24 h or more (p < 0.01). CONCLUSIONS: Hysteroscopic bipolar electric vaporization TCIS could be carried out safely and efficaciously in an outpatient setting, by using smaller hysteroscope and bipolar electrodes.