Vagus Nerve Stimulation Relives Irritable Bowel Syndrome and the Associated Depression via α7nAChR-mediated Anti-inflammatory Pathway.

OBJECTIVES: The present study is designed to investigate the role of vagus nerve in the treatments of irritable bowel syndrome (IBS) and the associated central nervous system disorders. METHODS: An IBS animal model was established by giving acetic acid and chronic-acute stress (AA-CAS) treatment in adult male Wistar rats. Subdiaphragmatic vagotomy (SDV) and vagus nerve stimulation (VNS) were performed to intervene the excitability of vagus nerve. Permeability of blood brain barrier (BBB) was measured and agonist and antagonist of α7 nicotinic acetylcholine receptor (α7nAChR) were used to explore the relevant mechanisms. RESULTS: AA-CAS treatment resulted in abnormal fecal output, increased visceral sensitivity, depressive-like behaviors, and overexpression of inflammatory mediators, all of which were reversed by VNS treatment. The effects of VNS could also be observed when α7nAChR agonist was applied. Whereas α7nAChR antagonist (methyllycaconitine, MLA) reversed VNS's effects. Interestingly, VNS also reduced the increased permeability of blood brain barrier (BBB) following AA-CAS treatment in IBS rats. SDV treatment only show temporary efficacy on AA-CAS-induced symptoms and had no effect on the permeability of BBB. CONCLUSION: The intestinal abnormalities and depressive symptoms in IBS rats can be improved by VNS treatment. This positive effect of VNS was achieved through α7nAChR-mediated inflammatory pathway and may also be associated with the decreased of BBB permeability.

Inhibiting Hypoxia and Chemotherapy-Induced Cancer Cell Metastasis under a Valid Therapeutic Effect by an Assistance of Biomimetic Oxygen Delivery.

Tumor metastasis is the most dangerous stage in tumorigenesis and its evolution, which causes about 80% clinical death. However, common therapies including chemotherapy may increase the risk of tumor metastasis while killing cancer cells. Tumor metastasis is closely related to many factors in the tumor microenvironment, especially hypoxia. As one of the characteristics of a malignant tumor microenvironment, hypoxia plays an important role in the growth, metabolism, and metastasis of tumors. Upregulation of the hypoxia-inducible factor (HIF) would stimulate the metastasis and migration of cancer cells. In this study, we developed an artificial oxygen carrier system, a hemoglobin-loaded liposome (Hb@lipo), which was capable of effectively delivering oxygen to tumor. The way of providing oxygen not only alleviated tumor hypoxia but also downregulated the expression of HIF, which is conducive to reducing tumor malignancy. Alleviating the tumor hypoxic microenvironment alone is not enough to inhibit tumor metastasis; thus, we prepared the liposome containing a chemotherapeutic agent cabazitaxel (CBZ@lipo). Our data indicated that the combination therapy of Hb@lipo and CBZ@lipo can efficiently kill cancer cells and inhibit tumor growth. At the same time, it can effectively entrap cancer cells in tumor sites by relieving the hypoxic microenvironment of tumors and reduce the metastasis of cancer cells during and after the chemotherapy. Our research may provide a clinical cancer chemotherapy reference that reduces the risk of cancer cell metastasis while inhibiting tumor growth.

Targeting Pancreatic Cancer Cells with Peptide-Functionalized Polymeric Magnetic Nanoparticles.

Pancreatic cancer is a concealed and highly malignant tumor, and its early diagnosis plays an increasingly weighty role during the course of cancer treatment. In this study, we developed a polymeric magnetic resonance imaging (MRI) nanoplatform for MRI contrast agents. To improve tumor-targeting delivery of MRI contrast agents, we employed a pancreatic cancer targeting CKAAKN peptide to prepare a peptide-functionalized amphiphilic hyaluronic acid-vitamin E succinate polymer (CKAAKN-HA-VES) for delivering ultra-small superparamagnetic iron oxide (USPIO), namely, CKAAKN-HA-VES@USPIO. With the modification of the CKAAKN peptide, CKAAKN-HA-VES@USPIO could specifically internalize into CKAAKN-positive BxPC-3 cells. The CKAAKN-HA-VES@USPIO nanoparticles presented a more specific accumulation into pancreatic cancer cells than normal pancreatic cells, and an obvious decrease in signal intensity was observed in CKAAKN-positive BxPC-3 cells, compared with CKAAKN-negative HPDE6-C7 cells and non-targeting HA-VES@USPIO nanoparticles. The results demonstrated that our polymeric MRI nanoplatform could selectively internalize into CKAAKN-positive pancreatic cancer cells by the specific binding of CKAAKN peptide with pancreatic cancer cell membrane receptors, which provided a novel polymeric MRI contrast agent with high specificity for pancreatic cancer diagnosis, and makes it a very promising candidate for magnetic resonance imaging contrast enhancement.

Near infrared light mediated photochemotherapy for efficiently treating deep orthotopic tumors guided by ultrasound imaging.

Recently, Combined cancer photothermal-chemotherapy has become a highly promising strategy in cancer treatment for its enhanced therapeutic efficacy, controlled drug release and reduced systemic toxicity. Almost all the reported strategies based on photothermal-chemotherapy have only focused on the treatment of superficial or subcutaneous cancer, which are not considered as a more clinically relevant and better predictive models of drug efficacy than orthotopic tumor models. Here, we reported an EphB4 receptor-targeting polymeric nanoplatform containing hollow gold nanospheres (HAuNS) and the anticancer drug paclitaxel (PTX) for cancer photothermal-chemotherapy. With the modification of the TNYL peptide, HP-TCS could specifically internalize into EphB4-positive SKOV3 and CT26 cells, further inducing the selective killing of the cells in co-cultured system, namely, EphB4-positive and EphB4-negative cells. Obvious targeting of the micelles into implanted orthotopic or subcutaneous tumors with high EphB4 expression was observed. Interestingly, increased accumulation of HP-TCS was observed in orthotopic colon tumors when compared with ectopic tumors. Highly specific accumulation of HP-TCS in EphB4-positive tumors significantly increased the feasibility of photothermal-chemotherapy mediated by the near infrared reflection (NIR) laser. Then, a systemic antitumor efficiency study was performed in implanted subcutaneous and visual orthotopic tumor models. Precise NIR laser irradiation could be localized on tumors under the guidance of B-mode ultrasound imaging, causing a rapid photothermal ablation effect limited to the region of tumors. Tumor growth was significantly inhibited by the photothermal-chemotherapy due to the triggered release of PTX. Our study provided a promising strategy of NIR laser-mediated photothermal-chemotherapy based on HP-TCS against the tumors (specially, deep orthotopic tumors) with high EphB4 expression.