Probiotics and severe acute pancreatitis

Lactobacillus casei combined with Lactobacillus reuteri alleviate pancreatic cancer by inhibiting TLR4 to promote macrophage M1 polarization and regulate gut microbial homeostasis

BACKGROUND

Pancreatic cancer is a highly lethal disease with no effective treatments. Lactobacillus casei (L. casei) and Lactobacillus reuteri (L. reuteri) exhibited therapeutic effects on several cancers, but their roles in pancreatic cancer are unknown. This study aims to explore how L. casei & L. reuteri influence pancreatic cancer and the underlying mechanisms.

METHODS

Pancreatic cancer cells were treated with L. casei & L. reuteri and co-cultured with macrophages in a transwell system in vitro. Pancreatic cancer xenograft model was established and L. casei & L. reuteri was used to treat mice in vivo. MTT, CCK-8 assay or immunohistochemical staining were used to determine the proliferation of pancreatic cancer cells or tumor tissues. Transwell assay was applied to test the migration and invasion of pancreatic cells. RT-qPCR was utilized to assess TLR4 and MyD88 expressions in pancreatic cells or tumor tissues. WB, immunofluorescence staining, or flow cytometry was used to evaluate the M1/M2 polarization of macrophages. Besides, the composition of gut microbiota of tumor-bearing mice was determined by 16 S rRNA sequencing, and ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS) untargeted metabolomics was used to evaluate the metabolic profiles of feces.

RESULTS

L. casei & L. reuteri inhibited the proliferation, migration, invasion of pancreatic cancer cells and pancreatic cancer cell-induced M2 polarization of macrophages by suppressing TLR4. Meanwhile, L. casei & L. reuteri repressed pancreatic cancer growth and promoted M1 macrophage polarization. Besides, L. casei & L. reuteri reduced fecal Alloprevotella and increased fecal azelate and glutamate in nude mice, while TLR4 inhibitor TAK-242 increased Clostridia UCG-014, azelate, uridine, methionine sulfoxide, oxypurinol, and decreased glyceryl monoester in the feces of pancreatic tumor-bearing mice. Fecal oxypurinol and glyceryl monoester levels were positively or negatively associated with gut Clostridia UCG-014 abundance, respectively.

CONCLUSION

L. casei & L. reuteri alleviate pancreatic cancer by inhibiting TLR4 to promote macrophage M1 polarization and regulate gut microbial homeostasis.

Bacterially mediated drug delivery and therapeutics: Strategies and advancements

It was already clinically apparent 150 years ago that bacterial therapy could alleviate diseases. Recently, a burgeoning number of researchers have been using bacterial regimens filled with microbial therapeutic leads to diagnose and treat a wide range of disorders and diseases, including cancers, inflammatory diseases, metabolic disorders and viral infections. Some bacteria that were designed to have low toxicity and high efficiency in drug delivery have been used to treat diseases successfully, especially in tumor therapy in animal models or clinical trials, thanks to the progress of genetic engineering and synthetic bioengineering. Therefore, genetically engineered bacteria can serve as efficient drug delivery vehicles, carrying nucleic acids or genetic circuits that encode and regulate therapeutic payloads. In this review, we summarize the development and applications of this approach. Strategies for genetically modifying strains are described in detail, along with their objectives. We also describe some controlled strategies for drug delivery and release using these modified strains as carriers. Furthermore, we discuss treatment methods for various types of diseases using engineered bacteria. Tumors are discussed as the most representative example, and other diseases are also briefly described. Finally, we discuss the challenges and prospects of drug delivery systems based on these bacteria.

Dietary, non-microbial intervention to prevent Helicobacter pylori-associated gastric diseases

Since the discovery of Helicobacter pylori (H. pylori) infection as the major cause of gastroduodenal disorders including acute and chronic gastritis, gastroduodenal ulcer, chronic atrophic gastritis, and gastric cancer almost three decades ago, the possibility of preventing these clinical diseases through eradicating H. pylori has been the focus of active research, but soon debate in the scientific community, though eradication opens the feasibility of cancer prevention and the removal of bacteria significantly prevents development or recurrence of peptic ulcer diseases and some clinical diseases, was proposed due to uncertainty in either achievement of complete eradication or inefficacy in cancer prevention with eradication alone. Still its linkage to gastric cancer is incontestable. Since the multiple combination of bacterial factors, environmental insults, and the host immune response that drives the initiation and progression of mucosal atrophy, metaplasia, and dysplasia toward gastric cancer is intervened, simple eradication deemed the feasibility of cancer prevention. Therefore, our group open strong hypothesis that non-microbial, dietary approach might be the alternate, for which several interventions of nutritional components can highlight rejuvenation of chronic atrophic gastritis as well as amelioration of H. pylori-associated procarcinogenic inflammation. In this review article, the experience and outcome regarding nutritional application to rejuvenate gastric atrophy will be introduced, using Korean red ginseng, garlic extracts, cancer preventive Korea kimchi, n-3 polyunsaturated fatty acids (PUFA), special form of licorice, and probiotics. The detailed influence of dietary intervention and bacterial eradication therapy on disease progression and reversibility of premalignant lesions are discussed.

Bugs or drugs: are probiotics safe for use in the critically ill?

Probiotics are living microorganisms which have demonstrated many benefits in prevention, mitigation, and treatment of various disease states in critically ill populations. These diseases include antibiotic-associated diarrhea, Clostridium difficile diarrhea, ventilator-associated pneumonia, clearance of vancomycin-resistant enterococci from the GI tract, pancreatitis, liver transplant, major abdominal surgery, and trauma. However, their use has been severely limited due to a variety of factors including a general naïveté within the physician community, lack of regulation, and safety concerns. This article focuses on uses for probiotics in prevention and treatment, addresses current concerns regarding their use as well as proposing a protocol for safe use of probiotics in the critically ill patient.

Non-microbial approach for Helicobacter pylori as faster track to prevent gastric cancer than simple eradication

Although the International Agency for Research on Cancer declared Helicobacter pylori (H. pylori) as a definite human carcinogen in 1994, the Japanese Society for Helicobacter Research only recently (February 2013) adopted the position that H. pylori infection should be considered as an indication for either amelioration of chronic gastritis or for decreasing gastric cancer mortality. Japanese researchers have found that H. pylori eradication halts progressive mucosal damage and that successful eradication in patients with non-atrophic gastritis most likely prevents subsequent development of gastric cancer. However, those who have already developed atrophic gastritis/gastric atrophy retain potential risk factors for gastric cancer. Because chronic perpetuated progression of H. pylori-associated gastric inflammation is associated with increased morbidity culminating in gastric carcinogenesis, a non-microbial approach to treatment that provides long-term control of gastric inflammation through nutrients and other interventions may be an effective way to decrease this morbidity. This non-microbial approach might represent a new form of prerequisite "rescue" therapy that provides a quicker path to the prevention of gastric cancer as compared to simple eradication.

Anti-inflammatory actions of probiotics through activating suppressor of cytokine signaling (SOCS) expression and signaling in Helicobacter pylori infection: a novel mechanism

BACKGROUND AND AIMS

In spite of the International Agency for Research on Cancer's definition that Helicobacter pylori is the definite carcinogen of gastric cancer, the simple eradication of the bug is not enough to prevent resultant gastric cancer, and increasing microbial resistance further limits the eradication application. Therefore, probiotics, non-pathogenic microbial feed that can affect the host in a beneficial manner, could be an alternate way to enhance anti-inflammation against H. pylori. However, the mechanism of their anti-inflammatory actions is still unclear. In the current study, we hypothesized that suppressor of cytokine signaling (SOCS) signaling could be a feasible anti-inflammatory mechanism of probiotics against H. pylori infection.

RESULTS

H. pylori infection or their lipopolysaccharide stimulation led to significant increased expressions of inflammatory mediators including tumor necrosis factor-alpha, interleukin-8, inducible nitric oxide synthase and cyclooxygenase-2 in AGS cells and pretreatment of Lactobacillus plantarum, Lactobacillus rhamnosis and Lactobacillus acidophilus significantly attenuated the expressions of these inflammatory mediators in accordance with the blocking action of nuclear factor-kappaB nuclear translocation. Probiotic administration increased expression of SOCS-2 and SOCS-3 and exerted the active SOCS signaling featured with earlier and higher expressions of SOCS-2 and SOCS-3. In contrast to weak inactivation of mitogen-activated protein kinases including p-38 and extracellular signal-regulated kinase 1/2, probiotic-induced SOCS expressions were mediated through either significant phosphorylation of signal transducers and activation of transcription (STAT)-1 and STAT-3 or simultaneous inhibition of Janus kinase (JAK)2 phosphorylation, which is known to signal SOCS-2/SOCS-3 negatively.

CONCLUSION

Anti-inflammatory signals of SOCS through STAT-1/STAT-3 activation and JAK2 inactivation might be a key anti-inflammatory mechanism of probiotics, setting probiotics as a non-microbial strategy to H. pylori infection.