Development and characterization of nanolipobeads-based dual drug delivery system forH. Pyloritargeting

Phage display-derived antibody fragments against conserved regions of VacA toxin of Helicobacter pylori

Infection with Helicobacter pylori may result in the emergence of gastric adenocarcinoma. Among various toxins assisting pathogenesis of H. pylori, the vacuolating cytotoxin A (VacA) is one of the most potent toxins known as the major cause of the peptic ulcer and gastric adenocarcinoma. To isolate single-chain variable fragments (scFvs) against two conserved regions of VacA, we capitalized on the phage display technology and a solution-phase biopanning (SPB). Characterization of scFvs was carried out by enzyme-linked immunosorbent assay (ELISA), immunoblotting, and surface plasmon resonance (SPR). Bioinformatics analyses were also performed in order to characterize the structural and functional properties of the isolated scFvs and the interaction(s) between the isolated antibodies (Ab)-antigen (Ag). After four rounds of biopanning, the positive colonies detected by scFv ELISA were harvested to extract the plasmids and perform sequencing. Of several colonies, three colonies showed high affinity to the VacA1 and two colonies for the VacA2. Further complementary examinations (e.g., sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), western blot, SPR, and flow cytometry) displayed the high affinity and specificity of the isolated scFvs to the VacA. Docking results revealed the interaction of the complementarity-determining regions (CDRs) with the VacA peptide. In conclusion, for the first time, we report on the isolation of several scFvs against conserved residues of VacA toxin with high affinity and specificity, which may be used as novel diagnostic/therapeutic tool in the H. pylori infection.

Anti-Helicobacterpylori effectiveness and targeted delivery performance of amoxicillin-UCCs-2/TPP nanoparticles based on ureido-modified chitosan derivative

The amoxicillin-UCCs-2/TPP nanoparticles constructed with ureido-modified chitosan derivative UCCs-2 and sodium tripolyphosphate (TPP) played an important role to deliver drug to achieve more efficacious and specific eradication of Helicobacterpylori (H. pylori) in vitro. In this study, the anti-H. pylori effectiveness in vivo and uptake mechanism was investigated in details, including the effect of temperature, pH values and the addition of competitive substrate urea on uptake. Compared with unmodified nanoparticles, a more efficacious and specific anti-H. pylori activities were obtained in vivo by using this biological chitosan derivative UCCs-2. Histological staining and immunological analysis verified that the amoxicillin-UCCs-2/TPP nanoparticles could diminish the proinflammatory cytokines levels and alleviate the inflammatory damages caused by H. pylori infection. The uredio-modified nanoparticles also have favorable gastric retention property, which is beneficial for the oral drug delivery to targeted eradicate H. pylori infection in stomach. These findings suggest that this targeted drug delivery system may serve for specific treatment of H. pylori infection both in vitro and in vivo, which can also be used as promising nanocarriers for other therapeutic reagents to target H. pylori.

Nanomedicines in gastroenterology and hepatology

Nanoscale systems are currently under investigation for multiple different diagnostic and therapeutic applications. These systems can be used to identify pathologically changed tissues or to selectively deliver drugs to these sites; both applications have an extremely high potential to ameliorate therapeutic outcomes for patients. Tissues as well as single cells can be targeted because of the small size of these systems, which enables enhanced diagnosis and increased specificity of therapy. Drug loads can be delivered directly to the site of action, which can result in a reduction in incidence and severity of adverse systemic effects. Several nano-based platform technologies are currently under investigation for use in therapeutic approaches, mainly for anti-inflammatory and anti-cancer therapies. Although many nanoscale systems show promising therapeutic outcomes in preclinical studies, only a limited number are ready for clinical use. This Review will discuss the diverse nanomaterials currently available and the first specific uses for select gastroenterological and hepatological pathologies. The discussion of diagnostic and therapeutic applications will consider realities of market introduction of these sometimes very complex systems in light of remaining regulatory challenges and hurdles for industrial production.

Eradication of Helicobacter pylori: Past, present and future

Helicobacter pylori is the major cause of chronic gastritis and peptic ulcers. Since the classification as a group 1 carcinogenic by International Agency for Research on Cancer, the importance of the complete H. pylori eradication has obtained a novel meaning. Hence, several studies have been made in order to deepen the knowledge in therapy strategies. However, the current therapy presents unsatisfactory eradication rates due to the lack of therapeutic compliance, antibiotic resistance, the degradation of antibiotics at gastric pH and their insufficient residence time in the stomach. Novel approaches have been made in order to overcome these limitations. The purpose of this review is to provide an overview about the current therapy and its limitations, while highlighting the possibility of using micro- and nanotechnology to develop gastric drug delivery systems, overcoming these difficulties in the future.