Effect of artificial gastrointestinal fluids on the excystation and metacystic development of Entamoeba invadens

Microbial Phosphorylation Product of Hesperetin by Bacillus subtilis BCRC 80517 Improves Oral Bioavailability in Rats

The flavanoid hesperidin (Hsd) is one of the major polyphenols in citrus fruits. Hsd and its aglycone hesperetin (Hst) have a broad array of bioactivities; however, their low aqueous solubility and low intestinal permeability lead to their limited oral bioavailability. In the present study, we generated two water-soluble derivatives of Hst, namely, Hst 7-O-phosphate and Hst3'-O-phosphate, by a unique bioconversion process of Bacillus subtilis var. natto BCRC80517. The phosphorylated products showed superior aqueous solubility and distinct physicochemical properties compared with the original Hst. The Hst phosphate derivatives (HstPs) remained stable in simulated gastric and intestinal fluids for 240 min and could revert to the original Hst form by alkaline phosphatase treatment in Caco-2 cells, showing enhanced intestinal permeability in vitro. After oral administration in rats, HstPs greatly elevated plasma exposure to Hst and showed better bioavailability than did Hsd. HstPs may be a potential and efficient alternative to Hst.

Acid-Suppressive Therapy and Risk of Infections: Pros and Cons

This narrative review summarises the benefits, risks and appropriate use of acid-suppressing drugs (ASDs), proton pump inhibitors and histamine-2 receptor antagonists, advocating a rationale balanced and individualised approach aimed to minimise any serious adverse consequences. It focuses on current controversies on the potential of ASDs to contribute to infections-bacterial, parasitic, fungal, protozoan and viral, particularly in the elderly, comprehensively and critically discusses the growing body of observational literature linking ASD use to a variety of enteric, respiratory, skin and systemic infectious diseases and complications (Clostridium difficile diarrhoea, pneumonia, spontaneous bacterial peritonitis, septicaemia and other). The proposed pathogenic mechanisms of ASD-associated infections (related and unrelated to the inhibition of gastric acid secretion, alterations of the gut microbiome and immunity), and drug-drug interactions are also described. Both probiotics use and correcting vitamin D status may have a significant protective effect decreasing the incidence of ASD-associated infections, especially in the elderly. Despite the limitations of the existing data, the importance of individualised therapy and caution in long-term ASD use considering the balance of benefits and potential harms, factors that may predispose to and actions that may prevent/attenuate adverse effects is evident. A six-step practical algorithm for ASD therapy based on the best available evidence is presented.

Apicomplexan infections in the gut

Toxoplasma gondii and Cryptosporidium parvum are intracellular protozoan parasites that establish infection through the small intestinal bowel after the ingestion of contaminated food products. These Apicomplexan parasites have emerged as an important cause of chronic and fatal disease in immunodeficient individuals, in addition to being investigated as possible triggers of inflammatory bowel disease. T. gondii disseminates to the brain and other tissues after infection, whereas C. parvum remains localized to the intestine. In the following review, we will discuss the pathogenesis of these parasitic diseases in the small intestine, the site of initial invasion. Themes include the sequence of invasion, the structure of Th1 immunity provoked by these parasites and the contribution of intestinal microbiota to the development of the mucosal immune response.

Compounds of the upper gastrointestinal tract induce rapid and efficient excystation of Entamoeba invadens

The infective stage of Entamoeba parasites is an encysted form. This stage can be readily generated in vitro, which has allowed identification of stimuli that trigger the differentiation of the parasite trophozoite stage into the cyst stage. Studies of the second differentiation event, emergence of the parasite from the cyst upon infection of a host, have been hampered by the lack of an efficient means to excyst the parasite and complete the life cycle in vitro. We have determined that a combination of exposures to water, bicarbonate and bile induces rapid excystment of Entamoeba invadens cysts. The high efficiency of this method has allowed the visualization of the dynamics of the process by electron and confocal microscopy, and should permit the analysis of stage-specific gene expression and high-throughput screening of inhibitory compounds.

Recent insights into Entamoeba development: identification of transcriptional networks associated with stage conversion

Entamoeba histolytica is an important human pathogen and a leading parasitic cause of death globally. The parasite life cycle alternates between the trophozoite form, which is motile and causes invasive disease and the cyst stage, which is environmentally resistant and transmits infection. Understanding the triggers that initiate stage conversion is an important yet understudied area of investigation. Recent progress in dissecting the transcriptional networks that regulate E. histolytica development is outlined in this paper.