Helicobacter pylori biofilms are disrupted by nanostructured lipid carriers: A path to eradication?

Carboxymethyl Chitosan Capped Bimetallic Nanoparticles Entrapped in Theranostic Nanofibers: Antimicrobial Peptide Coating, In Vitro, In Vivo Characterization for MDR Microbial Infection and Photoacoustic/Optical Imaging

Wound dressings, integrated with nanotechnology, have garnered considerable attention recently due to their ability to synergistically combine antimicrobial efficacy with wound healing properties, while also supporting adherence to standardized wound care protocols. We have developed smart theranostic wound dressings composed of carboxymethyl chitosan coated gold-silver-LL37 nanoparticles (G-S-CMC-Pep-NPs), of 155.1 ± 11.2 nm in size and a charge over the surface of +34.6 ± 3.7 mV. The optimized G-S-CMC-Pep-NPs were observed to exhibit minimal inhibitory and bactericidal concentration in the range of 0.390-0.781 μg/mL, also illustrated the maximum zone of inhibition (ZOI) of 21.61 ± 1.06 and 18.85 ± 1.22 mm, toward multidrug resistant (MDR) bacteria of P. aeruginosa and S. aureus respectively. TEM analysis of the microbial cells post-12-h treatment revealed irregularly undulating and disrupted cell walls, loss of cell wall integrity, and evidence of DNA condensation. Additionally, hemolysis assays demonstrated that G-S-CMC-Pep-NPs exhibited a nonhemolytic profile when tested on rodent blood, indicating their excellent biocompatibility. Furthermore, G-S-CMC-Pep-NPs were uniformly integrated into chitosan poly(vinyl alcohol) nanofibers (G-S-CMC-Pep-NPs-NFs) having a size ranging from 100 to 350 nm, resulting in an antimicrobial wound dressing, when applied to microbial-infected wounds in mice, achieved a 92.4% wound closure rate within 12 days of treatment. Additionally, this study is further substantiated through the analysis of wound marker protein expression levels, along with in vivo optical and ultrasound/photoacoustic imaging. The ultrasound/photoacoustic imaging offered an in-depth evaluation of the complex wound healing mechanism, enabling real-time visualization, high-resolution spatial imaging, and precise assessment of blood flow dynamics.

Nano-in-microparticles approach: Targeted gastric ulcer therapy using trans-resveratrol nanoparticles encapsulated in hyaluronic acid and alginate microparticles

Gastric ulcers affect 4 million people worldwide and occur when the stomach's defenses are compromised, allowing harmful agents, such as nonsteroidal anti-inflammatory drugs and Helicobacter pylori, to damage the tissue. The naturally occurring polyphenol, trans-resveratrol (RESV), demonstrates promising potential for treating gastric diseases. However, its therapeutic application is limited by its photosensitivity and solubility. To overcome these challenges, RESV was encapsulated in a new nano-in-microparticle system comprised of chitosan nanoparticles incorporated into hyaluronic acid and alginate microparticles (RESV-MNP). RESV-MNP exhibited spherical morphology (~2 μm) and encapsulation efficiency of 79 %, releasing about 41 % of RESV within 24 h, showing a prolonged release profile compared to the free drug. Additionally, RESV-MNP interacted with porcine mucin in an acid environment. RESV-MNP showed no toxicity against AGS/MKN-74 cell lines in vitro and in acute toxicity tests using Galleria mellonella and hemolysis. RESV-MNP presented a minimum inhibitory and bactericidal concentration (MIC/MBC) of 3.9 μg/mL, eradicating H. pylori after 24 h. At 2×MIC, RESV-MNP completely eradicated H. pylori biofilm. In an in vitro infection assay, RESV-MNP reduced H. pylori load. The formulation effectively reduced the mortality rate of H. pylori-infected larvae in the G. mellonella model. Furthermore, RESV-MNP demonstrated gastroprotective effects, reducing the extent and severity of indomethacin-gastric lesions in rats.

Review on bacterial outer membrane vesicles: structure, vesicle formation, separation and biotechnological applications

Outer membrane vesicles (OMVs), shed by Gram-negative bacteria, are spherical nanostructures that play a pivotal role in bacterial communication and host-pathogen interactions. Comprising an outer membrane envelope and encapsulating a variety of bioactive molecules from their progenitor bacteria, OMVs facilitate material and informational exchange. This review delves into the recent advancements in OMV research, providing a comprehensive overview of their structure, biogenesis, and mechanisms of vesicle formation. It also explores their role in pathogenicity and the techniques for their enrichment and isolation. Furthermore, the review highlights the burgeoning applications of OMVs in the field of biomedicine, emphasizing their potential as diagnostic tools, vaccine candidates, and drug delivery vectors.

Combatting Helicobacter pylori: A Focus on Nanomaterials

Developing effective non-antibiotic antimicrobial strategies is essential for combating global antibiotic resistance, including resistance stemming from Helicobacter pylori (H. pylori) treatment. Nanomaterials offer a promising and innovative approach for non-antibiotic anti-H. pylori treatment strategies. This review highlights the progress made in the use of metallic and nonmetallic nanoparticles, as well as nanozymes, to directly inhibit H. pylori growth. Moreover, we summarize advances made in the direct targeting of H. pylori by nanomaterials and the stimuli-responsive release of nanoparticles in the stomach. Additionally, we explore the recent advancements in multifunctional nanoplatforms that integrate physical methods, such as light, heat, ultrasound, and magnetism, with nanomaterials to synergistically treat H. pylori infections. Finally, we briefly address the existing challenges and future directions in this field. In summary, we highlight that with ongoing research, nanomaterials may serve as a promising treatment strategy for H. pylori eradication.

Opportunities for Helicobacter pylori Eradication beyond Conventional Antibiotics

Helicobacter pylori (H. pylori) is a bacterium known to be associated with a significant risk of gastric cancer in addition to chronic gastritis, peptic ulcer, and MALT lymphoma. Although only a small percentage of patients infected with H. pylori develop gastric cancer, Gastric cancer causes more than 750,000 deaths worldwide, with 90% of cases being caused by H. pylori. The eradication of this bacterium rests on multiple drug regimens as guided by various consensus. However, the efficacy of empirical therapy is decreasing due to antimicrobial resistance. In addition, biofilm formation complicates eradication. As the search for new antibiotics lags behind the bacterium's ability to mutate, studies have been directed toward finding new anti-H. pylori agents while also optimizing current drug functions. Targeting biofilm, repurposing outer membrane vesicles that were initially a virulence factor of the bacteria, phage therapy, probiotics, and the construction of nanoparticles might be able to complement or even be alternatives for H. pylori treatment. This review aims to present reports on various compounds, either new or combined with current antibiotics, and their pathways to counteract H. pylori resistance.

Engineering resveratrol-loaded chitosan nanoparticles for potential use against Helicobacter pylori infection

Helicobacter pylori (H. pylori) is a microorganism directly linked to severe clinical conditions affecting the stomach. The virulence factors and its ability to form biofilms increase resistance to conventional antibiotics, growing the need for new substances and strategies for the treatment of H. pylori infection. The trans-resveratrol (RESV), a bioactive polyphenol from natural sources, has a potential activity against this gastric pathogen. Here, Chitosan nanoparticles (NP) containing RESV (RESV-NP) were developed for H. pylori management. The RESV-NP were prepared using the ionic gelation method and characterized by Dynamic Light Scattering (DLS), Nanoparticle Tracking Analysis (NTA) and, Cryogenic Transmission Electron Microscopy (Cryo - TEM). The encapsulation efficiency (EE) and in vitro release rate of RESV were quantified using high-performance liquid chromatography (HPLC). RESV-NP performance against H. pylori was evaluated by the quantification of the minimum inhibitory/bactericidal concentrations (MIC/MBC), time to kill, alterations in H. pylori morphology in its planktonic form, effects against H. pylori biofilm and in an in vitro infection model. RESV-NP cytotoxicity was evaluated against AGS and MKN-74 cell lines and by hemolysis assay. Acute toxicity was tested using Galleria mellonella model assays. RESV-NP showed a spherical shape, size of 145.3 ± 24.7 nm, polydispersity index (PDI) of 0.28 ± 0.008, and zeta potential (ZP) of + 16.9 ± 1.81 mV in DLS, while particle concentration was 3.12 x 1011 NP/mL (NTA). RESV-NP EE was 72 %, with full release within the first 5 min. In microbiological assays, RESV-NP presented a MIC/MBC of 3.9 µg/mL, a time to kill of 24 h for complete eradication of H. pylori. At a concentration of 2xMIC (7.8 µg/mL), RESV-NP completely eradicated the H. pylori biofilm, and in an in vitro infection model, RESV-NP (4xMIC - 15.6 µg/mL) showed a significant decrease in bacterial load (1 Log10CFU/mL) when compared to the H. pylori J99 control. In addition, they did not demonstrate a toxic character at MIC concentration for both cell lines. The use of the RESV-NP with mucoadhesion profile is an interesting strategy for oral administration of substances targeting gastric disorders, linked to H. pylori infections.

One-Pot Microfluidics to Engineer Chitosan Nanoparticles Conjugated with Antimicrobial Peptides Using "Photoclick" Chemistry: Validation Using the Gastric Bacterium Helicobacter pylori

Surface bioconjugation of antimicrobial peptides (AMP) onto nanoparticles (AMP-NP) is a complex, multistep, and time-consuming task. Herein, a microfluidic system for the one-pot production of AMP-NP was developed. Norbornene-modified chitosan was used for NP production (NorChit-NP), and thiolated-AMP was grafted on their surface via thiol-norbornene "photoclick" chemistry over exposure of two parallel UV LEDs. The MSI-78A was the AMP selected due to its high activity against a high priority (level 2) antibiotic-resistant gastric pathogen: Helicobacter pylori (H. pylori). AMP-NP (113 ± 43 nm; zeta potential 14.3 ± 7 mV) were stable in gastric settings without a cross-linker (up to 5 days in pH 1.2) and bactericidal against two highly pathogenic H. pylori strains (1011 NP/mL with 96 μg/mL MSI-78A). Eradication was faster for H. pylori 26695 (30 min) than for H. pylori J99 (24 h), which was explained by the lower minimum bactericidal concentration of soluble MSI-78A for H. pylori 26695 (32 μg/mL) than for H. pylori J99 (128 μg/mL). AMP-NP was bactericidal by inducing H. pylori cell membrane alterations, intracellular reorganization, generation of extracellular vesicles, and leakage of cytoplasmic contents (transmission electron microscopy). Moreover, NP were not cytotoxic against two gastric cell lines (AGS and MKN74, ATCC) at bactericidal concentrations. Overall, the designed microfluidic setup is a greener, simpler, and faster approach than the conventional methods to obtain AMP-NP. This technology can be further explored for the bioconjugation of other thiolated-compounds.

Recent trends in Helicobacter pylori management: harnessing the power of AI and other advanced approaches

Background

Helicobacter pylori (H. pylori) is a bacterial infection that is prevalent and affects more than half of the world's population, causing stomach disorders such as gastritis, peptic ulcer disease, and gastric cancer.

Main body

The diagnosis of H. pylori infection relies on invasive and non-invasive techniques emerging artificial intelligence, and antibiotic therapy is available, but antibiotic resistance is a growing concern. The development of a vaccine is crucial in preventing H. pylori-associated diseases, but it faces challenges due to the bacterium's variability and immune escape mechanisms. Despite the challenges, ongoing research into H. pylori's virulence factors and immune escape mechanisms, as well as the development of potential vaccine targets, provides hope for more effective management and prevention of H. pylori-associated diseases. Recent research on H. pylori's immune escape mechanisms and novel immune checkpoint inhibitors could also lead to biomarkers for early cancer detection. Therefore, experts have suggested a combination of traditional and herbal medicine with artificial intelligence to potentially eradicate H. pylori.

Short conclusion

H. pylori infection remains a significant global health problem, but ongoing research into its properties and advanced technologies in addition to the combination of traditional and herbal medicine with artificial intelligence may also lead to the eradication of H. pylori-associated diseases.

Graphical abstract

Therapeutic effect of demethylated hydroxylated phillygenin derivative on Helicobacter pylori infection

Modifying and transforming natural antibacterial products is a novel idea for developing new efficacious compounds. Phillygenin has an inhibitory effect on H. pylori. The aim of the present study was to prepare a phillygenin derivative (PHI-Der) through demethylation and hydroxylation. The minimum inhibitory concentration of 18 strains of H. pylori from different sources was 8-32 μg/mL in vitro, and the activity increased 2-8 times than that of phillygenin. PHI-Der could significantly inhibit the colonization of H. pylori in vivo, reduce the inflammatory response, and promote the repair of inflammatory damage. Further, we used SwissTargetPrediction to predict that its main targets are ALOX5, MCL1, and SLC6A4, and find that it can inhibit bacterial biofilm formation and reduce bacterial infection of cells. It can enhance the intracellular oxidative capacity of H. pylori to inhibit H. pylori growth. Further, it could prevent the oxidation of H. pylori-infected cells and reduce the inflammatory response, which plays a role in protection. In conclusion, compared to phillygenin, PHI-Der had better antibacterial activity and was more effective in treating H. pylori infection. It has characteristics of high safety, specificity, resistance to drug resistance and better antibacterial activity than phillygenin, it's a good antioxidant for host cells.

How Charge, Size and Protein Corona Modulate the Specific Activity of Nanostructured Lipid Carriers (NLC) against Helicobacter pylori

The major risk factor associated with the development of gastric cancer is chronic infection with Helicobacter pylori. The available treatments, based on a cocktail of antibiotics, fail in up to 40% of patients and disrupt their gut microbiota. The potential of blank nanostructured lipid carriers (NLC) for H. pylori eradication was previously demonstrated by us. However, the effect of NLC charge, size and protein corona on H. pylori-specific bactericidal activity herein studied was unknown at that time. All developed NLC formulations proved bactericidal against H. pylori. Although cationic NLC had 10-fold higher bactericidal activity than anionic NLC, they lacked specificity, since Lactobacillus acidophilus was also affected. Anionic NLC achieved complete clearance in both H. pylori morphologies (rod- and coccoid-shape) by inducing alterations in bacteria membranes and the cytoplasm, as visualized by transmission electron microscopy (TEM). The presence of an NLC protein corona, composed of 93% albumin, was confirmed by mass spectrometry. This protein corona delayed the bactericidal activity of anionic NLC against H. pylori and hindered NLC activity against Escherichia coli. Overall, these results sustain the use of NLC as a promising antibiotic-free strategy targeting H. pylori.