Fighting AMR of hard-to-reach microbial pathogens by repurposing antibiotics using a targeted liposomal delivery strategy: A Helicobacter pilot study

背景：抗菌素耐药性（AMR）是对全球健康的主要威胁，特别是在获得抗生素限制较少的低收入国家，导致经常过度使用抗生素。这反过来又导致以前有效的抗生素越来越不能根除感染。幽门螺杆菌（Hp）是一种感染越南80%成人和70%儿童的细菌。相比之下，英国许多地区的患病率低于15%。抗菌素耐药性菌株的日益流行是控制Hp失败的关键原因，导致更高的医疗费用，以及相关疾病的死亡率和发病率增加。2015年在越南进行的一项研究发现，42.4%的菌株对克拉霉素耐药，41.3%对左氧氟沙星耐药，76.1%对甲硝唑耐药。ODA依从性：Hp是导致胃肠道溃疡和胃癌的主要原因。据认为，越南的高患病率和高再感染率取决于社会经济地位低下，例如生活拥挤和卫生条件差。现在，在Hp患病率和相关疾病（如胃癌）方面，低收入国家和富裕国家之间存在巨大差异。后者是越南第四大最常见的癌症类型，但在英国仅排在第16位。惠普对较为脆弱的人群的影响尤其强烈；癌症（如由Hp引起的胃癌）是越南弱势群体贫困的一个重要原因，与治疗费用相关，使许多家庭陷入贫困。因此，我们的项目，旨在培训越南科学家和临床医生在尖端的先进药物输送方面，使越南卫生系统能够开发并最终将这种新疗法提供给一般人群。因此，根据官方发展援助原则，这可能会给越南人口中较贫困的部分带来长期的社会经济效益。抗菌药物治疗无法根除Hp感染的一个根本原因是，在粘稠粘液下和隐窝中，药物对细菌的可及性较低。进一步的因素是药物在胃中的停留时间短，以及某些抗生素对胃酸的敏感性。因此，一些在体外对Hp非常有效的抗生素在体内无效。通过增加胃潴留时间和保护抗生素不受胃酸的影响来解决这两个问题，将提高根除Hp感染的治疗效果，同时允许使用目前无法使用的现有抗生素。重新利用抗生素是一种非常具有成本效益的策略，可以快速跟踪药物开发过程。我们的长期目标是通过减少胃肠道溃疡和胃癌的患病率，为改善越南人口的健康做出贡献。我们建议使用功能化脂质体来解决胃潴留时间短和胃酸失活的问题。由于在其表面添加了两种Hp粘附素（BabA和LabA），它们将粘附在胃上皮和粘液上。包裹在功能化脂质体中的药物胃潴留的增加将通过纳米spect - ct成像在体内得到验证，我们已经在小鼠身上成功进行了测试。我们将在体外通过测量与人胃细胞系AGS的结合来评估功能化脂质体与上皮细胞的结合，AGS稳定转染了人MUC5AC， MUC5AC是一种粘蛋白，含有用于脂质体功能化的BabA和LabA的生理配体。筛选来自英国和越南的约600个临床Hp分离株将使我们能够确定不同水平的AMR，并使我们能够在体外测试我们的功能化脂质体的有效性和安全性（例如细胞毒性）。最后，将利用已建立的小鼠感染模型在体内评估该制剂根除Hp的能力。

Background: Antimicrobial resistance (AMR) is a major threat to global health, particularly in low-income countries, where access to antibiotics is less restricted, leading to frequent overuse. This in turn leads to increasing failure of previously efficacious antibiotics to eradicate infection. H. pylori (Hp) is a bacterium infecting 80% of adults and 70% of children In Vietnam. In comparison, prevalence is <15% in many parts of the UK. The increasing prevalence of AMR strains is the crucial cause for failure in controlling Hp, leading to higher medical costs, and increased mortality and morbidity from related diseases. A 2015 study in Vietnam found 42.4% strains resistant to clarithromycin, 41.3% to levofloxacin, and 76.1% to metronidazole. ODA compliance: Hp is the main cause of gastrointestinal ulcers and stomach cancer. The high prevalence of disease and a high rate of reinfection in Vietnam is thought to depend on the low socioeconomic status, e.g. crowded living and poor hygienic conditions. There is now a huge discrepancy between low income and affluent countries in terms of Hp prevalence and related diseases, such as gastric cancer. The latter is the 4th most common type of cancer in Vietnam, but only the 16th in the UK. The impact of Hp is particularly strong on the more vulnerable sections of the population; cancer (e.g. gastric cancer caused by Hp) is a significant cause of impoverishment associated with the costs of its treatment in vulnerable sections of the Vietnamese population, pushing many households into poverty. Therefore, our project, which is designed to train Vietnamese scientists and clinicians in cutting-edge advanced drug delivery, empowering the Vietnamese health system to develop and ultimately make available this new treatment to the general population. Hence it is likely to lead to long term socioeconomic benefits to poorer sections of the Vietnamese population, in line with official development assistance principles.One cause underlying the failure of antimicrobial treatment to eradicate Hp infection is the low accessibility of the drug to the bacterium, underneath the thick mucus and in crypts. Further factors are the short retention times of drugs in the stomach, and the susceptibility of some antibiotics to stomach acid. As a result, some antibiotics which are highly effective against Hp in vitro have failed in vivo. Solving these two problems, by increasing the gastric retention time and protecting the antibiotics from the stomach acid, would increase efficacy of treatment in eradicating Hp infection while allowing the use of existing antibiotics which currently cannot be used. Repurposing of antibiotics is a very cost-effective strategy to fast-track the drug development process. Our long term aim is to contribute to improve the health of the population in Vietnam by reducing the prevalence of GI ulcers and gastric cancer. We suggest solving the problem of short gastric retention times and gastric acid inactivation by using functionalized liposomes. These will adhere to the gastric epithelium and mucus due to the addition of two Hp adhesins (BabA and LabA) on their surface. The increased gastric retention of drugs encapsulated in the functionalized liposomes will be verified in vivo using NanoSPECT-CT imaging, which we have successfully tested in mice. Binding of functionalized liposomes to epithelial cells will be assessed in vitro by measuring binding to human gastric cell line AGS stably transfected with human MUC5AC, a mucin which contains the physiological ligands of BabA and LabA used for liposome functionalization. Screening of ~600 clinical Hp isolates from both the UK and Vietnam will allow us to identify various levels of AMR and allow us to test the efficacy and safety (e.g. cell toxicity) of our functionalized liposomes in vitro. Finally, the ability of this formulation to eradicate Hp will be assessed in vivo using am established murine infection model.