Site-specific adaptation mechanisms of an oral pathobiont in the oral and gut mucosae

Periodontal inflammation leads to oral dysbiosis with the expansion of oral pathobionts. Besides the pathogenic role of oral pathobionts during periodontal inflammation, studies have revealed that oral pathobionts contribute to diseases in distant organs beyond the oral mucosa. For example, the oral pathobiont Klebsiella aerogenes, which accumulates in the oral mucosa during periodontitis in mice, can exacerbate colitis when it ectopically colonizes the gastrointestinal tract. However, the precise mechanisms by which oral pathobionts establish their colonization in extra-oral mucosal sites remains incompletely understood. We performed high-throughput in vivo genetic screening to identify fitness genes required for the adaptation of the oral pathobiont K. aerogenes to different mucosal sites – the oral and gut mucosae – in the steady state and during inflammation. In addition, the global transcriptome of K. aerogenes in different environments was analyzed. We determined that K. aerogenes employs genes related to iron acquisition and chaperone usher pili, which are encoded on a newly identified genomic locus named “locus of colonization in the inflamed gut” (LIG), for adaptation in the gut mucosa, particularly during inflammation. In contrast, the LIG virulence factors are not required for K. aerogenes to adapt to the oral mucosa. Thus, oral pathobionts likely exploit distinct adaptation mechanisms in their ectopically colonized intestinal niche as compared to their original niche.

The transcription factor HIF-1α mediates plasticity of NKp46+ innate lymphoid cells in the gut

Gut innate lymphoid cells (ILCs) show remarkable phenotypic diversity, yet microenvironmental factors that drive this plasticity are incompletely understood. The balance between NKp46+, IL-22–producing, group 3 ILCs (ILC3s) and interferon (IFN)-γ–producing group 1 ILCs (ILC1s) contributes to gut homeostasis. The gut mucosa is characterized by physiological hypoxia, and adaptation to low oxygen is mediated by hypoxia-inducible transcription factors (HIFs). However, the impact of HIFs on ILC phenotype and gut homeostasis is not well understood. Mice lacking the HIF-1α isoform in NKp46+ ILCs show a decrease in IFN-γ–expressing, T-bet+, NKp46+ ILC1s and a concomitant increase in IL-22–expressing, RORγt+, NKp46+ ILC3s in the gut mucosa. Single-cell RNA sequencing revealed HIF-1α as a driver of ILC phenotypes, where HIF-1α promotes the ILC1 phenotype by direct up-regulation of T-bet. Loss of HIF-1α in NKp46+ cells prevents ILC3-to-ILC1 conversion, increases the expression of IL-22–inducible genes, and confers protection against intestinal damage. Taken together, our results suggest that HIF-1α shapes the ILC phenotype in the gut.

Improving gut function in pigs to prevent pathogen colonization

Intestinal pathogens causing either clinical or sub-clinical infections increase pig morbidity and (or) mortality, resulting in economic losses and wider socio-economic impacts on pig production. An optimally functioning gastrointestinal tract (GIT) is fundamental to combatting intestinal pathogen colonisation at all the stages of life. This requires successful development and maintenance of key gut functions: digestive function; the gastro-intestinal cell line barrier; gut-associated lymphoid tissue (GALT); and gut-associated microbiota. This chapter first discusses research on genes associated with pathogen resistance and porcine immune response. It then reviews risk factors associated with gut mucosa impairment as well as dietary strategies to control risk factors and improve gut functionality in preventing intestinal pathogen colonisation.

Healthy and pro-inflammatory gut ecology plays a crucial role in the digestion and tolerance of a novel Gluten Friendly™ bread in celiac subjects: a randomized, double blind, placebo control in vivo study

Gluten Friendly™ (GF) is a new gluten achieved through a physicochemical process applied to wheat kernels. The goal of this research was to assess the in vivo effects of Gluten Friendly™ bread on celiac gut mucosa and microbiota.

Do NSAIDs Take Us Away From Treatment Goals in Axial Spondyloarthritis: A Story About Dysbiosis or Just a Matter of Bias?

Non-steroidal anti-inflammatory drugs (NSAIDs) remain the mainstay of treatment for spondyloarthritides (SpA), a group of entities with common clinical and pathophysiological aspects, but also with differential features. Although NSAIDs provide significant symptomatic relief, especially for joint pain and morning stiffness, their role in achieving and maintaining the treatment goals advocated by the treat to target strategy in SpA is not entirely clear. These agents can induce changes in the composition of the intestinal microbiota, also favoring an alteration of the barrier function in the gut epithelium. All of this, favored by a pre-disposing genetic background, could activate a specific type of aberrant immune response in the gut lamina propria, also known as type-3 immunity. This article offers a perspective on how NSAIDs, despite their undeniable value in the short-term SpA treatment, could hinder the achievement of medium and long-term treatment goals by compromising the barrier function of the gut mucosa and potentially altering the composition of the gut microbiota.

Use of Bacillus Subtilis Probiotics as Non-Antibiotic Gut Modulator and Growth Promoter in Broiler Chickens

Wide range of Antibiotics is being used as feed additives in Animal industry in order to get rid from pathogens and as growth promoters in developing world. But after the suggested prohibition on using antibiotics, products such as probiotics are getting substantial importance in nutrition because of their non-resistant and non-residual possessions. Basic aim of the chapter is to highlight fruitful effects of Bacillus Subtilis as non-antibiotic gut modulator and growth promoter in broiler chickens. Probiotics are the living culture of microorganisms. They flourish in the gut of the host and fortify the growth of valuable commensals in the digestive tract by minimizing the destruction triggered by pathogens, boost up the immune system, supporting the integrity of the gut mucosa and maintain a stability and balance of normal microflora. Probiotics can be used as best substitute to conventional antimicrobial therapy. In addition, it has been observed that probiotics plays a role in growth enhancement by augmenting useful enzymes in the body and promote the growth of other normal commensals such as Lactobacillus and having effect on gut luminal pH. Probiotics are quite active against intestinal pathogens in several ways, viz. including improved immune elimination, competing for mucosal attachment, striving for crucial nutrients, or producing antimicrobial complexes contrary to numerous enteropathogens. It can be concluded that B. Subtilis has the ability to modulate gut and immune system histophysiology and histomorphology and can be used as safe antimicrobial candidate in poultry nutrition. Knowledge of such possessions of the B. Subtilis as probiotics and the mechanisms of action may enable the researchers to manipulate the use of such alternatives for better growth production, and safe and healthy poultry industry.

Gliadin proteolytical resistant peptides: the interplay between structure and self-assembly in gluten-related disorders

In recent years, the evaluation of the structural properties of food has become of crucial importance in the understanding of food-related disorders. One of the most exciting systems is gliadin, a protein in wheat gluten, that plays a protagonist role in gluten-related disorders with a worldwide prevalence of 5%, including autoimmune celiac disease (CeD) (1%) and non-celiac wheat sensitivity (0.5–13%). It is accepted that gliadin is not fully digested by humans, producing large peptides that reach the gut mucosa. The gliadin peptides cross the lamina propria eliciting different immune responses in susceptible patients. Many clinical and biomedical efforts aim to diagnose and understand gluten-related disorders; meanwhile, the early stages of the inflammatory events remain elusive. Interestingly, although the primary sequence of many gliadin peptides is well known, it was only recently revealed the self-assembly capability of two pathogenic gliadin fragments and their connection to the early stage of diseases. This review is dedicated to the most relevant biophysical characterization of the complex gliadin digest and the two most studied gliadin fragments, the immunodominant 33-mer peptide and the toxic p31-43 in connection with inflammation and innate immune response. Here, we want to emphasize that combining different biophysical methods with cellular and in vivo models is of key importance to get an integrative understanding of a complex biological problem, as discussed here.

Acute GvHD after HLA-Haploidentical Hematopoietic Cell Transplantation with Regulatory and Conventional T Cell Immunotherapy Does Not Adversely Affect Transplantation Outcomes

Introduction Adoptive immunotherapy with CD4+CD25+FOXP3+ regulatory T cells (Tregs) and conventional T cells (Tcons) has been employed after allogeneic hematopoietic stem cell transplantation (HSCT) to prevent Graft-versus-Host Disease (GvHD) while mantaining Graft-versus-Leukemia effect in the absence of any further immune suppressive GvHD prophylaxis (Di Ianni, Blood 2011; Martelli, Blood 2014). A recent study of age-adapted haploidentical HSCT with Treg/Tcon adoptive immunotherapy (Treg/Tcon haplo-HSCT) resulted in an unprecedented 75% chronic GvHD (cGvHD)/leukemia-free survival (CRFS) in acute myeloid leukemia patients. Acute GvHD (aGvHD) occured in 33% of patients and was the most frequent complication of the procedure (Pierini, Blood Advances 2021). Here, we analyzed clinical and histological characteristics of aGvHD and evaluated its impact on outcomes in patients who received Treg/Tcon haplo-HSCT. Methods We retrieved data of patients who underwent Treg/Tcon haplo-HSCT at Perugia University Hospital and who were evaluable for aGvHD from January 2015 until June 2021 (clinicaltrials.gov: NCT03977103). Histological features and lymphoid infiltration by immunohistochemistry were analyzed in gut samples of patients who received diagnostic colonscopy and biopsy for gastrointestinal symptoms. Results A total of 105 patients engrafted after Treg/Tcon haplo-HSCT. Mean age at transplant was 48 years (range 18-70). Acute leukemia was the most frequent diagnosis (78/105 myeloid, 23/105 lymphoblastic), 4 patients had myelodisplastic syndrome and 2 multiple myeloma. Twenty-seven (26%) patients had active disease at the time of HSCT. Fourteen (13%) patients received Treg/Tcon haplo-HSCT as a second HSCT procedure. Thirty-one (29%) patients developed grade II-IV aGvHD. Four patients had grade II aGvHD, 23 grade III, and 4 grade IV. Almost all patients (90%) presented gut involvement, while skin was involved in 64% of them and liver in 35%. To explain why gut symptoms such as diarrhea and abdominal pain were more frequently present than symptoms of skin or liver involvement, we evaluated 40 histological samples from 34 patients who received colonoscopy for suspected aGvHD. Twenty-two of them (65%) received a clinical diagnosis of aGvHD and pharmacological immune suppression was promptly started. Clinical diagnosis did not always match histological findings: biopsies were suggestive of aGvHD in 20/22 patients who required treatment, but also in 8/12 patients who did not. We found no difference in median CD3+ cell infiltration among patients who did not need immune suppressive treatments and patients with aGvHD (460 cells/mmq vs 446 cells/mmq). However, FOXP3+ Tregs preferentially infiltrated gut mucosa of patients who resolved clinical symptoms with no need of immune suppressive treatments (120 cells/mmq vs 59 cells/mmq, p = 0.008; FOXP3/CD3 ratio: 0.27 vs 0.18, p = 0.004). This observation suggested Treg defective homing to gut mucosa of aGvHD patients. Indeed, we found infused Tregs expressed lower levels of gut homing receptor α4β7 in comparison with Tcons (p< .001). Despite severe presentation at diagnosis, aGvHD resolved in the majority of patients (71%), and immune suppressive therapy could be completely withdrawn after a relatively short-course (median: 98 days, range 48-404). Sixteen/31 patients (52%) were steroid refractory and required further treatments after first-line (e.g. Ruxolitinib). Only two of them developed moderate/severe cGvHD and one is alive and off-therapy. Indeed, aGvHD diagnosis did not result in higher incidence of non-relapse mortality (cumulative incidence of 29% in aGvHD patients vs 27% in controls; p=non significant, ns, Fig.1A), relapse (13% vs 20%; p=ns, Fig.1B), or cGvHD (6.5% vs 3%; p=ns, Fig.1C). In fact, CRFS of aGvHD patients was similar to CRFS of patients that did not develop aGvHD (Fig. 1D, p=ns, median follow up of live patients: 1246 days). Conclusions Treg/Tcon haplo-HSCT is followed by low rates of relapse and cGvHD and results in good CRFS in high risk leukemia patients. aGvHD after Treg/Tcon haplo-HSCT preferentially involves the gut where Treg homing is defective. Strategies that enhance Treg homing in the gut (e.g. low-dose IL-2) may help reduce aGvHD after Treg/Tcon haplo-HSCT. In conclusion, despite aGvHD occurred in 29% of patients, it was responsive to treatments and it did not result in disease relapse or cGvHD. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Severe complicated shigellosis case developed by young pregnant woman

No doubts that shigellosis severity directly depends on the spread of the gut specific lesion. There are some data published on the basis of autopsy records and pointing to shigella caused lesion spreading both to colon and ileum in adult cases especially in those older than 60 y.o. or with any immunosuppressive premorbid background. Obviously, the gut mucosa condition determines the local resistance potential and moreover it's shown that in shigellosis cases, the histologic pattern of gut mucosa depends on quantity and quality of neutrophils, extremely important to control the intensity of agent invasion. Viral infections with concomitant neutropenia are commonly considered as immune suppressive conditions. As to Herpes virus infection, it's well known as the large mucosa lesion disease that can subsequently lead to aggravation of any forthcoming acute bacterial infection. The paper suggests the description of shigellosis case confirmed with the use of PCR test (PCR kit Amplisens All-bacto-screen-FL Lab, Interlabservice) and developed by young woman with unfavorable premorbid condition. The disease course turned to be severe and complicated by the peritonitis development. The aggravating factors in the proposed case were likely such immune modulating concurrent conditions as Herpes virus infection and pregnancy. The clinical example demonstrates that young people can develop severe complicated shigellosis course given burdened premorbid background availability.

Role of Dietary Fiber in the Correction of Gut Microbiocenosis Disorders Against the Background of Antibacterial Therapy

Antibiotic-associated gut microbiocenosis disorders develop on average in every third patient in the form of both mild disorders and severe life-threatening conditions. The negative impact of antibacterial agents on the gut microbiota causes a decrease in the number and species diversity of microorganisms that produce butyric acid. Low concentrations of butyric acid can often induce inflammatory and atrophic processes of the gut mucosa, the water-electrolyte balance regulation disorders and, as a result, the gut motility and functions disorders. Long-term gut microbiocenosis disorders themselves can cause the development of the disease and in future, they become factors of its progression, thereby launching a whole cascade of new pathological processes. The article analyzes a representative clinical data published in authoritative international magazines from 1990 to 2020, indicating the effectiveness of the dietary fiber (DF) management for the correction of gut microbiocenosis disorders caused by antibacterial drugs intake. Partially hydrolyzed guar gum, registered in our country under the trade name “OptiFiber”, due to its effects such as the gut regulation, abdominal pain reduction, flatus and bloating reduction, increase the resident gut microflora amount and its metabolic activity, helps to restore and maintain of the gut eubiosis. Conclusion. “OptiFiber” can be administered for a long-term intake in order to increase the effectiveness of antibiotic therapy for various infectious diseases, as well as for the correction and prevention of gut microbiocenosis disorders associated with antibacterial drugs intake