The Interplay between Immunity and Microbiota at Intestinal Immunological Niche: The Case of Cancer

Exploring the Exposome Spectrum: Unveiling Endogenous and Exogenous Factors in Non-Communicable Chronic Diseases

The exposome encompasses all endogenous and exogenous exposure individuals encounter throughout their lives, including biological, chemical, physical, psychological, relational, and socioeconomic factors. It examines the duration and intensity of these types of exposure and their complex interactions over time. This interdisciplinary approach involves various scientific disciplines, particularly toxicology, to understand the long-term effects of toxic exposure on health. Factors like air pollution, racial background, and socioeconomic status significantly contribute to diseases such as metabolic, cardiovascular, neurodegenerative diseases, infertility, and cancer. Advanced analytical methods measure contaminants in biofluids, food, air, water, and soil, but often overlook the cumulative risk of multiple chemicals. An exposome analysis necessitates sophisticated tools and methodologies to understand health interactions and integrate findings into precision medicine for better disease diagnosis and treatment. Chronic exposure to environmental and biological stimuli can lead to persistent low-grade inflammation, which is a key factor in chronic non-communicable diseases (NCDs), such as obesity, cardiometabolic disorders, cancer, respiratory diseases, autoimmune conditions, and depression. These NCDs are influenced by smoking, unhealthy diets, physical inactivity, and alcohol abuse, all shaped by genetic, environmental, and social factors. Dietary patterns, especially ultra-processed foods, can exacerbate inflammation and alter gut microbiota. This study investigates the exposome's role in the prevention, development, and progression of NCDs, focusing on endogenous and exogenous factors.

Gut microbiota and immunotherapy of renal cell carcinoma

The gut microbiome has recently been proposed as a key player in cancer development and progression. Several studies have reported that the composition of the gut microbiome plays a role in the response to immune checkpoint inhibitors (ICIs). The gut microbiome modulation has been investigated as a potential therapeutic strategy for cancer, mainly in patients undergoing therapy with ICIs. In particular, modulation through probiotics, FMT or other microbiome-related approaches have proven effective to improve the response to ICIs. In this review, we examine the role of the gut microbiome in enhancing clinical responses to ICIs in the treatment of renal cancer.

The Interplay between Helicobacter pylori and Gut Microbiota in Non-Gastrointestinal Disorders: A Special Focus on Atherosclerosis

The discovery of Helicobacter pylori (H. pylori) in the early 1980s by Nobel Prize winners in medicine Robin Warren and Barry Marshall led to a revolution in physiopathology and consequently in the treatment of peptic ulcer disease. Subsequently, H. pylori has also been linked to non-gastrointestinal diseases, such as autoimmune thrombocytopenia, acne rosacea, and Raynaud's syndrome. In addition, several studies have shown an association with cardiovascular disease and atherosclerosis. Our narrative review aims to investigate the connection between H. pylori infection, gut microbiota, and extra-gastric diseases, with a particular emphasis on atherosclerosis. We conducted an extensive search on PubMed, Google Scholar, and Scopus, using the keywords "H. pylori", "dysbiosis", "microbiota", "atherosclerosis", "cardiovascular disease" in the last ten years. Atherosclerosis is a complex condition in which the arteries thicken or harden due to plaque deposits in the inner lining of an artery and is associated with several cardiovascular diseases. Recent research has highlighted the role of the microbiota in the pathogenesis of this group of diseases. H. pylori is able to both directly influence the onset of atherosclerosis and negatively modulate the microbiota. H. pylori is an important factor in promoting atherosclerosis. Progress is being made in understanding the underlying mechanisms, which could open the way to interesting new therapeutic perspectives.

Gut-Kidney-Heart: A Novel Trilogy

The microbiota represents a key factor in determining health and disease. Its role in inflammation and immunological disorders is well known, but it is also involved in several complex conditions, ranging from neurological to psychiatric, from gastrointestinal to cardiovascular diseases. It has recently been hypothesized that the gut microbiota may act as an intermediary in the close interaction between kidneys and the cardiovascular system, leading to the conceptualization of the "gut-kidney-heart" axis. In this narrative review, we will discuss the impact of the gut microbiota on each system while also reviewing the available data regarding the axis itself. We will also describe the role of gut metabolites in this complex interplay, as well as potential therapeutical perspectives.

Pancreatic Ductal Adenocarcinoma and Nutrition: Exploring the Role of Diet and Gut Health

The incidence of pancreatic cancer is increasing worldwide. The most common form is represented by pancreatic ductal adenocarcinoma (PDAC) which has been shown to be linked to chronic inflammation. Notably, the gut microbiota has emerged as a critical player in regulating immune responses and inflammation. Indeed, intestinal dysbiosis, characterized by an imbalance in the gut microbiota composition, can contribute to the initiation of chronic inflammation. Sterile chronic inflammation can occur, probably activated by the translocation of bacterial components, such as lipopolysaccharide (LPS), the major component of Gram-negative microbiota, with the consequent induction of innate mucosal immunity, through the activation of Toll-like receptors (TLRs). Furthermore, the interaction between LPS and TLRs could enhance cancer progression. Recent research has shed light on the pivotal role of nutrition, as a modifiable risk factor, in PDAC immunological processes, particularly focusing on the immuno-modulatory effects of the gut microbiota. Different dietary regimens, fiber intake, immunonutrients, and antioxidants have the potential to either exacerbate or mitigate chronic inflammation, thereby influencing the pathogenesis and natural history of PDAC. These dietary components may affect the gut microbiota composition and, consequently, the level of inflammation, either promoting or protecting against PDAC. In this review of reviews, we discuss the modulatory role of nutrition and the gut microbiota in PDAC's immunological processes to explore a translational therapeutic approach that could improve the survival and quality of life of these patients.

The toxic mechanism of 6:2 Cl-PFESA in adolescent male rats: Endocrine disorders and liver inflammation regulated by the gut microbiota-gut-testis/liver axis

In previous studies, 6:2 chlorinated polyfluorinated ether sulfonic acid (6:2 Cl-PFESA), a perfluorooctanesulfonate alternative, has been demonstrated to be toxic to mammals. However, the toxic mechanism of 6:2 Cl-PFESA in mammals is unknown. Herein, adolescent male rats were administered 50 μg/kg/Day 6:2 Cl-PFESA for 28 days (oral gavage) to estimate the toxicity of 6:2 Cl-PFESA and investigate its toxic mechanism. Significant changes in some hematological indicators (e.g., aspartate transaminase and neutrophils) and liver sections (inflammatory cell infiltration) indicated that 6:2 Cl-PFESA exposure caused rat hepatotoxicity. Six steroid hormones (e.g., testosterone, progesterone, and cortisol) in serum and thirteen genes in testicles (related to the pathway of steroid hormone biosynthesis) were significantly regulated in 6:2 Cl-PFESA-treated rats. This suggested that 6:2 Cl-PFESA induced rat endocrine disorders. Compared to the controls, the mean relative abundance of Ruminococcaceae, Pasteurellaceae, Micrococcaceae, and Desulfovibrionaceae was significantly regulated by 1.3-, 0.40-, 0.32-, and 3.2-fold in the 6:2 Cl-PFESA rats, respectively. The 6:2 Cl-PFESA treatment also significantly disturbed 47 gut metabolites (29 upregulated and 18 downregulated), mainly bile acids, short-chain fatty acids, and amino acids. In summary, 6:2 Cl-PFESA induced endocrine disorders and liver inflammation in rats by altering the gut microbiota-gut-testis/liver axis. This study first reveals the toxic mechanism of 6:2 Cl-PFESA in mammals through a multiomics approach and provides comprehensive insight into the toxic mechanism of 6:2 Cl-PFESA.

The Role of Gut Dysbiosis in the Loss of Intestinal Immune Cell Functions and Viral Pathogenesis

The gut microbiome plays a critical role in maintaining overall health and immune function. However, dysbiosis, an imbalance in microbiome composition, can have profound effects on various aspects of human health, including susceptibility to viral infections. Despite numerous studies investigating the influence of viral infections on gut microbiome, the impact of gut dysbiosis on viral infection and pathogenesis remains relatively understudied. The clinical variability observed in SARS-CoV-2 and seasonal influenza infections, and the presence of natural HIV suppressors, suggests that host-intrinsic factors, including the gut microbiome, may contribute to viral pathogenesis. The gut microbiome has been shown to influence the host immune system by regulating intestinal homeostasis through interactions with immune cells. This review aims to enhance our understanding of how viral infections perturb the gut microbiome and mucosal immune cells, affecting host susceptibility and response to viral infections. Specifically, we focus on exploring the interactions between gamma delta (γδ) T cells and gut microbes in the context of inflammatory viral pathogenesis and examine studies highlighting the role of the gut microbiome in viral disease outcomes. Furthermore, we discuss emerging evidence and potential future directions for microbiome modulation therapy in the context of viral pathogenesis.

Histamine-producing bacteria and their role in gastrointestinal disorders

INTRODUCTION

Gut microbiota produces thousands of metabolites, which have a huge impact on the host health. Specific microbial strains are able to synthesize histamine, a molecule with a crucial role in many physiologic and pathologic mechanisms of the host. This function is mediated by the histidine decarboxylase enzyme (HDC) that converts the amino acid histidine to histamine.

AREAS COVERED

This review summarizes the emerging data on histamine production by gut microbiota, and the effect of bacterial-derived histamine in different clinical contexts, including cancer, irritable bowel syndrome, and other gastrointestinal and extraintestinal pathologies. This review will also outline the impact of histamine on the immune system and the effect of probiotics that can secrete histamine. Search methodology: we searched the literature on PubMed up to February 2023.

EXPERT OPINION

The potential of modulating gut microbiota to influence histamine production is a promising area of research, and although our knowledge of histamine-secreting bacteria is still limited, recent advances are exploring their diagnostic and therapeutical potential. Diet, probiotics, and pharmacological treatments directed to the modulation of histamine-secreting bacteria may in the future potentially be employed in the prevention and management of several gastrointestinal and extraintestinal disorders.

Short-Chain Fatty-Acid-Producing Bacteria: Key Components of the Human Gut Microbiota

Short-chain fatty acids (SCFAs) play a key role in health and disease, as they regulate gut homeostasis and their deficiency is involved in the pathogenesis of several disorders, including inflammatory bowel diseases, colorectal cancer, and cardiometabolic disorders. SCFAs are metabolites of specific bacterial taxa of the human gut microbiota, and their production is influenced by specific foods or food supplements, mainly prebiotics, by the direct fostering of these taxa. This Review provides an overview of SCFAs' roles and functions, and of SCFA-producing bacteria, from their microbiological characteristics and taxonomy to the biochemical process that lead to the release of SCFAs. Moreover, we will describe the potential therapeutic approaches to boost the levels of SCFAs in the human gut and treat different related diseases.

The role of diet in shaping human gut microbiota

Gut microbiota plays a fundamental role within human health, and exerts key functions within the human body. Diet is one of the most powerful modulators of gut microbiota functions and composition. This complex interplay involves also the immune system and the intestinal barrier, highlighting the central role of diet in the pathogenesis and treatment of multiple diseases. In this review article we will paint the landscape of the effects of specific dietary nutrients, and of the detrimental or beneficial outcomes of different dietary patterns, on the composition of human gut microbiota. Moreover, we will discuss the potential application of diet as a therapeutic modulator of gut microbiota, including cutting-edge ways of exploitation, including the use of dietary components as adjuvants to promote microbial engraftment after fecal microbiota transplantation, or personalized nutritional approaches, targeted to the patient microbiome.

Effects of Losartan, Atorvastatin, and Aspirin on Blood Pressure and Gut Microbiota in Spontaneously Hypertensive Rats

Many studies have shown that alterations in the gut microbiota are associated with hypertension. Our study aimed to observe the characteristics of the gut microbiota in hypertension and to further explore whether drug molecules can play a therapeutic role in hypertension by interfering with the gut microbiota. We evaluated the differences in the composition of the gut microbiota in spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). Meanwhile, three first-line cardiovascular disease (CVD) drugs, losartan, atorvastatin, and aspirin, were used to treat the SHR in order to observe their effects on the gut microbiota in SHR. The 16S rDNA results showed that the diversity and richness of the gut microbiota in SHR were significantly reduced compared with that of the WKY, the Firmicutes/Bacteroidetes ratio was increased, the abundances of Bifidobacterium and short chain fatty acids (SCFAs)-producing bacteria decreased, and the abundance of lactate-producing bacteria increased. In addition to lowering the blood pressure, losartan increased the abundances of Alistipes, Bacteroides, and Butyricimonas in SHR, reduced the abundances of Ruminococcaceae, Streptococcus, and Turicibacter, reduced the Firmicutes/Bacteroidetes ratio, and rebalanced the gut microbiota. Losartan also increased the abundances of Bifidobacterium and SCFAs-producing bacteria and reduced the abundance of lactate-producing bacteria. However, atorvastatin and aspirin had no significant effect on the gut microbiota in SHR. The above results showed that losartan could change the characteristics of the gut microbiota in hypertension and rebalance the gut microbiota, which may be related to lowering the blood pressure. Atorvastatin and aspirin have no significant influence on the gut microbiota in SHR.

Gut Microbiota Host-Gene Interaction

Studies carried out in the last ten years have shown that the metabolites made up from the gut microbiota are essential for multiple functions, such as the correct development of the immune system of newborns, interception of pathogens, and nutritional enrichment of the diet. Therefore, it is not surprising that alteration of the gut microbiota is the starting point of gastrointestinal infection, obesity, type 2 diabetes, inflammatory bowel disease, colorectal cancer, and lung cancer. Diet changes and antibiotics are the major factors damaging the gut microbiota. Early exposure of the newborns to antibiotics may prevent their correct development of the immune system, exposing them to pathogen infections, allergies, and chronic inflammatory diseases. We already know much on how host genes, microbiota, and the environment interact, owing to experiments in several model animals, especially in mice; advances in molecular technology; microbiota transplantation; and comparative metagenomic analysis. However, much more remains to be known. Longitudinal studies on patients undergoing to therapy, along with the identification of bacteria prevalent in responding patients may provide valuable data for improving therapies.

The interplay between Helicobacter pylori and the gut microbiota: An emerging driver influencing the immune system homeostasis and gastric carcinogenesis

The human gut microbiota are critical for preserving the health status because they are required for digestion and nutrient acquisition, the development of the immune system, and energy metabolism. The gut microbial composition is greatly influenced by the colonization of the recalcitrant pathogen Helicobacter pylori (H. pylori) and the conventional antibiotic regimens that follow. H. pylori is considered to be the main microorganism in gastric carcinogenesis, and it appears to be required for the early stages of the process. However, a non-H. pylori microbiota profile is also suggested, primarily in the later stages of tumorigenesis. On the other hand, specific groups of gut microbes may produce beneficial byproducts such as short-chain fatty acids (acetate, butyrate, and propionate) that can modulate inflammation and tumorigenesis pathways. In this review, we aim to present how H. pylori influences the population of the gut microbiota to modify the host immunity and trigger the development of gastric carcinogenesis. We will also highlight the effect of the gut microbiota on immunotherapeutic approaches such as immune checkpoint blockade in cancer treatment to present a perspective for further development of innovative therapeutic paradigms to prevent the progression of H. pylori-induced stomach cancer.

Emerging role of human microbiome in cancer development and response to therapy: special focus on intestinal microflora

In recent years, there has been a greater emphasis on the impact of microbial populations inhabiting the gastrointestinal tract on human health and disease. According to the involvement of microbiota in modulating physiological processes (such as immune system development, vitamins synthesis, pathogen displacement, and nutrient uptake), any alteration in its composition and diversity (i.e., dysbiosis) has been linked to a variety of pathologies, including cancer. In this bidirectional relationship, colonization with various bacterial species is correlated with a reduced or elevated risk of certain cancers. Notably, the gut microflora could potentially play a direct or indirect role in tumor initiation and progression by inducing chronic inflammation and producing toxins and metabolites. Therefore, identifying the bacterial species involved and their mechanism of action could be beneficial in preventing the onset of tumors or controlling their advancement. Likewise, the microbial community affects anti-cancer approaches’ therapeutic potential and adverse effects (such as immunotherapy and chemotherapy). Hence, their efficiency should be evaluated in the context of the microbiome, underlining the importance of personalized medicine. In this review, we summarized the evidence revealing the microbiota's involvement in cancer and its mechanism. We also delineated how microbiota could predict colon carcinoma development or response to current treatments to improve clinical outcomes.

The crosstalk between gut microbiota, intestinal immunological niche and visceral adipose tissue as a new model for the pathogenesis of metabolic and inflammatory diseases: the paradigm of type 2 diabetes mellitus

Gut microbiota (GM) comprises more than one thousand microorganisms between bacterial species, viruses, fungi, and protozoa, and represents the main actor of a wide net of molecular interactions, involving, among others, the endocrine system, immune responses, and metabolism. GM influences many endocrine functions such as adrenal steroidogenesis, thyroid function, sexual hormones, IGF-1 pathway and peptides produced in gastrointestinal system. It is fundamental in glycaemic control and obesity, while also exerting an important function in modulating the immune system and associated inflammatory disease. The result of this crosstalk in gut mucosa is the formation of the intestinal immunological niche. Visceral adipose tissue (VAT) produces about 600 different peptides, it is involved in lipid and glucose metabolism and in some immune reactions through several adipokines. GM and VAT interact in a bidirectional fashion: while gut dysbiosis can modify VAT adipokines and hormone secretion, VAT hyperplasia modifies GM composition. Acquired or genetic factors leading to gut dysbiosis or increasing VAT (i.e., Western diet) induce a proinflammatory condition, which plays a pivotal role in the development of dysmetabolic and immunologic conditions, such as diabetes mellitus. Diabetes is clearly associated with specific patterns of GM alterations, with an abundance or reduction of GM species involved in controlling mucosal barrier status, glycaemic levels and exerting a pro- or anti-inflammatory activity. All these factors could explain the higher incidence of several inflammatory conditions in Western countries; furthermore, besides the specific alterations observed in diabetes, this paradigm could represent a common pathway acting in many metabolic conditions and could pave the way to a new, interesting therapeutic approach.

Combination Therapy in Renal Cell Carcinoma: the Best Choice for Every Patient?

PURPOSE OF REVIEW

Therapeutic alternatives to treat metastatic renal cell carcinoma (mRCC) are increasing, and combination therapies, including antiangiogenic agents and tyrosine kinase/mTOR/immune checkpoint inhibitors, are identified as the gold standard driven by the results of recent clinical studies. Nevertheless, the real-world RCC population is very heterogeneous, with categories of patients not represented in the enrolled trial population who may not benefit more from these treatments. The purpose of this expert review is to assess the rationale on which tyrosine kinase alone may still be a viable first-line treatment option for some subgroups of patients with mRCC.

RECENT FINDINGS

The first-line treatment with tyrosine kinase inhibitor monotherapy can still be considered an effective tool for addressing selected mRCCs, as highlighted by the successful outcome in a range of subjects such as favorable-risk patients, the ones suffering from autoimmune diseases, those with pancreatic or lung metastases, or previously undergoing organ transplantation and elderly subjects. Some selected categories of patients may still benefit from monotherapy with TKI, and smart sequential therapies can also be considered instead of a combination strategy. Tyrosine kinase inhibitors can also act as immune modulator agents, boosting the immune response to facilitate and potentiate the therapeutic effectiveness of subsequent immunotherapy.

Novel insights on gut microbiota manipulation and immune checkpoint inhibition in cancer (Review)

Cancer affects millions of individuals worldwide. Thus, there is an increased need for the development of novel effective therapeutic approaches. Tumorigenesis is often coupled with immunosuppression which defeats the anticancer immune defense mechanisms activated by the host. Novel anticancer therapies based on the use of immune checkpoint inhibitors (ICIs) are very promising against both solid and hematological tumors, although still exhibiting heterogeneous efficacy, as well as tolerability. Such a differential response seems to derive from individual diversity, including the gut microbiota (GM) composition of specific patients. Experimental evidence supports the key role played by the GM in the activation of the immune system response against malignancies. This observation suggests to aim for patient-tailored complementary therapies able to modulate the GM, enabling the selective enrichment in microbial species, which can improve the positive outcome of ICI-based immunotherapy. Moreover, the research of GM-derived predictive biomarkers may help to identify the selected cancer population, which can benefit from ICI-based therapy, without the occurrence of adverse reactions and/or cancer relapse. The present review summarizes the landmark studies published to date, which have contributed to uncovering the tight link existing between GM composition, cancer development and the host immune system. Bridging this triangle of interactions may ultimately guide towards the identification of novel biomarkers, as well as integrated and patient-tailored anticancer approaches with greater efficacy.

Concomitant use of analgesics and immune checkpoint inhibitors in non-small cell lung cancer: A pharmacodynamics perspective

The invention of immunotherapy, such as immune checkpoint inhibitors (ICIs) for advanced-stage non-small cell lung cancer (NSCLC), has become a new standard of care for a defined group of NSCLC patients. However, the possible impacts of ICI interactions with analgesics for alleviating cancer-related pain are unclear and lack clinical evidence. Many studies have indicated that opioids detrimentally affect the immune system, possibly harming patients of ongoing immunotherapy. Opioids may repress the immune system in various ways, including impairing T cell function, upregulating immunosuppressor Treg cells, and interrupting intestinal microflora composition that disrupts the entire immune system. Furthermore, opioids can influence tumor progression and metastasis directly as opioid receptors are overexpressed in several types of NSCLC. In contrast, another analgesic acting on cyclooxygenase (COX) inhibition (i.e., NSAIDs) may be a candidate for adjuvant therapy since COX-2 is also expressed in the tumor cells of NSCLC patients. In addition, COX-2 is associated with tumor proliferation and metastasis. Therefore, both prospective and retrospective studies should confirm the advantages and disadvantages of the concurrent use of analgesics and ICIs in a clinical setting.

The role of gut microbiome in modulating response to immune checkpoint inhibitor therapy in cancer

Immunotherapy has led to a paradigm shift in the treatment of several cancers. There have been significant efforts to identify biomarkers that can predict response and toxicities related to immune checkpoint inhibitor (ICPI) therapy. Despite these advances, it has been challenging to tease out why a subset of patients benefit more than others or why certain patients experience immune-related adverse events (irAEs). Although the immune-modulating properties of the human gut bacterial ecosystem are yet to be fully elucidated, there has been growing interest in evaluating the role of the gut microbiome in shaping the therapeutic response to cancer immunotherapy. Considerable research efforts are currently directed to utilizing metagenomic and metabolic profiling of stool microbiota in patients on ICPI-based therapies. Dysbiosis or loss of microbial diversity has been associated with a poor treatment response to ICPIs and worse survival outcomes in cancer patients. Emerging data have shown that certain bacterial strains, such as Faecalibacterium that confer sensitivity to ICPI, also have a higher propensity to increase the risk of irAEs. Additionally, the microbiome can modulate the local immune response at the intestinal interface and influence the trafficking of bacterial peptide primed T-cells distally, influencing the toxicity patterns to ICPI. Antibiotic or diet induced alterations in composition of the microbiome can also indirectly alter the production of certain bacterial metabolites such as deoxycholate and short chain fatty acids that can influence the anti-tumor tolerogenesis. Gaining sufficient understanding of the exact mechanisms underpinning the interplay between ICPI induced anti-tumor immunity and the immune modulatory role gut microbiome can be vital in identifying potential avenues of improving outcomes to cancer immunotherapy. In the current review, we have summarized and highlighted the key emerging data supporting the role of gut microbiome in regulating response to ICPIs in cancer.

Molecular profiling of the intestinal mucosa and immune cells of the colon by multi-parametric histological techniques

The impact of the post-mortem interval (PMI) on the optical molecular characteristics of the colonic mucosa and the gut-associated lymphoid tissue (GALT) were examined by multi-parametric measurements techniques. Inflammatory cells were identified by immunohistochemical staining. Molecular parameters were estimated using the Raman spectroscopy (RS) and Fourier Transform Infrared (FTIR) spectroscopic imaging. The 3D refractive index (3D-RI) distributions of samples were determined using the digital holographic tomography. The distribution of immune cells between post-mortem (PM) and normal controls did show significant differences for CD4 (P = 0.0016) or CD8 (P < 0.0001), whose expression level was decreased in PM cases. No association was found between individual PMI values and inflammatory cell distribution. However, there was a tendency for a negative correlation between CD4⁺ cells and PMI (r = - 0.542, P = 0.032). The alterations ongoing in post-mortem tissue may suggest that PMI has a suppressive effect on the effector properties of the cell-mediated immunity. Moreover, it was confirmed that spectroscopic and digital holotomographic histology are also a useful technique for characterization of the differences in inflammation of varying intensity and in GALT imaging in a solid tissue. Anatomical location of immune cells and methods of tissue fixation determine the molecular and optical parameters of the examined cases.

Gut Microbiota and Acute Diverticulitis: Role of Probiotics in Management of This Delicate Pathophysiological Balance

How can the knowledge of probiotics and their mechanisms of action be translated into clinical practice when treating patients with diverticular disease and acute diverticulitis? Changes in microbiota composition have been observed in patients who were developing acute diverticulitis, with a reduction of taxa with anti-inflammatory activity, such as Clostridium cluster IV, Lactobacilli and Bacteroides. Recent observations supported that a dysbiosis characterised by decreased presence of anti-inflammatory bacterial species might be linked to mucosal inflammation, and a vicious cycle results from a mucosal inflammation driving dysbiosis at the same time. An alteration in gut microbiota can lead to an altered activation of nerve fibres, and subsequent neuronal and muscular dysfunction, thus favoring abdominal symptoms' development. The possible role of dysbiosis and mucosal inflammation in leading to dysmotility is linked, in turn, to bacterial translocation from the lumen of the diverticulum to perivisceral area. There, a possible activation of Toll-like receptors has been described, with a subsequent inflammatory reaction at the level of the perivisceral tissues. Being aware that bacterial colonisation of diverticula is involved in the pathogenesis of acute diverticulitis, the rationale for the potential role of probiotics in the treatment of this disease becomes clearer. For this review, articles were identified using the electronic PubMed database through a comprehensive search conducted by combining key terms such as "gut microbiota", "probiotics and gut disease", "probiotics and acute diverticulitis", "probiotics and diverticular disease", "probiotics mechanism of action". However, the amount of data present on this matter is not sufficient to draw robust conclusions on the efficacy of probiotics for symptoms' management in diverticular disease.

Luteolin, inflammation and cancer: Special emphasis on gut microbiota

Luteolin belongs to the family of flavonoids, which have anti-inflammatory functions, potentially useful in a clinical context, particularly for patients suffering from cancer, neuropsychiatric disorders, inflammatory bowel conditions. This peculiarity has been used for centuries in traditional Chinese medicine, for many different diseases. Its anti-inflammatory effects might be particularly relevant in cancer, with some studies reporting anti-angiogenesis, anti-metastatic, and apoptotic effects on cancer cells by luteolin and other flavonoids. In this article, we analyze the anti-inflammatory role of luteolin, discussing the pathways it may act on. We will then discuss the possible role of microbiota in inflammatory modulation by luteolin. Finally, the possible therapeutic applications of luteolin's anti-inflammatory properties will be analyzed, with a particular focus on cancer.

Effect of Daikenchuto On Spontaneous Intestinal Tumors in ApcMin/+ Mice

Daikenchuto (TU-100) is herbal medicine which predominantly contains ginger, Japanese pepper, and ginseng. We investigated whether TU-100 can affect the composition of gut flora and intestinal tumor development using Apc^Min/+ mice, a murine model of intestinal tumor. Bacterial 16S rRNA sequencing and short-chain fatty acid analysis were performed on faecal samples. Tumor number and size were analysed. Any change in gene expression of the tumor tissues was assessed by real-time PCR. Principal coordinate analysis (PCoA) showed that the faecal microbiota cluster of TU-100-fed mice was different from the microbiota of control mice. However, no significant difference was observed in the concentration of short-chain fatty acids, tumor number, and gene expression levels between the two groups. Our data showed that TU-100 can affect the intestinal environment; however, it does not contribute in tumor progression or inhibition in our setting.

The Interplay between Immunosenescence and Microbiota in the Efficacy of Vaccines

Vaccinations are among the most effective medical procedures and have had an incredible impact on almost everyone’s life. One of the populations that can benefit the most from them are elderly people. Unfortunately, in this group, vaccines are less effective than in other groups, due to immunosenescence. The immune system ages like the whole body and becomes less effective in responding to infections and vaccinations. At the same time, immunosenescence also favors an inflammatory microenvironment, which is linked to many conditions typical of the geriatrics population. The microbiota is one of the key actors in modulating the immune response and, in this review, we discuss the current evidence on the role of microbiota in regulating the immune response to vaccines, particularly in elderly people.

Antibiotics, cancer risk and oncologic treatment efficacy: a practical review of the literature

Antibiotics have been extensively used to treat infectious diseases over the past century and have largely contributed to increased life expectancy over time. However, antibiotic use can impose profound and protracted changes to the diversity of the microbial ecosystem, affecting the composition of up to 30% of the bacterial species in the gut microbiome. By modifying human microbiota composition, antibiotics alter the action of several oncologic drugs, potentially leading to decreased efficacy and increased toxicities. Whether antibiotics interfere with cancer therapies or even increase the risk of cancer development has been under investigation, and no randomised trials have been conducted so far. The aim of the current review is to describe the possible effects of antibiotic therapies on different oncologic treatments, especially immunotherapies, and to explore the link between previous antibiotics use and the development of cancer.

Influence of microbiota on immunity and immunotherapy for gastric and esophageal cancers

Gastric and esophageal cancers are multifactorial and multistage-involved malignancy. While the impact of gut microbiota on overall human health and diseases has been well documented, the influence of gastric and esophageal microbiota on gastric and esophageal cancers remains unclear. This review will discuss the reported alteration in the composition of gastric and esophageal microbiota in normal and disease conditions, and the potential role of dysbiosis in carcinogenesis and tumorigenesis. This review will also discuss how dysbiosis stimulates local and systemic immunity, which may impact on the immunotherapy for cancer.

Manipulating Gut Microbiota Composition to Enhance the Therapeutic Effect of Cancer Immunotherapy

In the past decade, a growing set of immunotherapies including immune checkpoint blockade, chimeric antigen receptor T cells, and bispecific antibodies propelled the advancement of oncology therapeutics. Accumulating evidence demonstrates that immunotherapy could eliminate tumors better than traditional chemotherapy or radiotherapy with lower risk of adverse events in numerous cancer types. Unfortunately, a substantial proportion of patients eventually acquire resistance to immunotherapy. By analyzing the differences between immunotherapy-sensitive and immunotherapy-resistant populations, it was noticed that the composition of gut microbiota is closely related to treatment effect. Moreover, in xenograft models, interventional regulation of gut microbiota could effectively enhance efficacy and relieve resistance during immunotherapy. Thus, we believe that gut microbiota composition might be helpful to explain the heterogeneity of treatment effect, and manipulating gut microbiota could be a promising adjuvant treatment for cancer immunotherapy. In this mini review, we focus on the latest understanding of the cross-talk between gut microbiota and host immunity. Moreover, we highlight the role of gut microbiota in cancer immunotherapy including immune checkpoint inhibitor and adoptive cell transfer.

The Differences between Luminal Microbiota and Mucosal Microbiota in Mice

The differences between luminal microbiota (LM) and mucosal microbiota (MAM) were little known, especially in duodenum. In this study, LM and MAM in colon and duodenum of mice were investigated through 16S rRNA high-throughput sequencing. The lowest bacterial diversity and evenness were observed in duodenal LM (D_LM), followed by duodenal MAM (D_MAM). Meanwhile, the bacterial diversity and evenness were obviously increased in D_MAM than these in D_LM, while no significant difference was observed between colonic MAM (C_MAM) and colonic LM (C_LM). PCoA analysis also showed that bacterial communities of LM and MAM in duodenum were completely separated, while these in colon overlapped partly. The ratio of Firmicutes to Bacteroidetes (F/B) in D_MAM was significantly higher than that in D_LM. Lactobacillus was largely enriched and was the characteristic bacteria in D_LM. The characteristic bacteria in D_MAM were Turicibacter, Parasutterella, Marvinbryantia and Bifidobacterium, while in C_LM they were Ruminiclostridium_6, Ruminiclostridium_9, Ruminococcaceae_UCG_007 and Lachnospiraceae_UCG_010, and in C_MAM they were Lachnospiraceae_NK4A136, Mucispirillum, Alistipes, Ruminiclostridium and Odoribacter. The networks showed that more interactions existed in colonic microbiota (24 nodes and 74 edges) than in duodenal microbiota (17 nodes and 29 edges). The 16S rDNA function prediction results indicated that bigger differences of function exist between LM and MAM in duodenum than these in colon. In conclusion, microbiota from intestinal luminal content and mucosa were different both in colon and in duodenum, and bacteria in colon interacted with each other much more closely than those in duodenum.

Risk factors for bloodstream infections in gynecological cancer

OBJECTIVE

Infections are a threat to frail patients as they have a higher risk of developing serious complications from bloodstream pathogens. The aim of this study was to determine which factors can predict or diagnose bloodstream infections in patients with an underlying gynecologic malignancy.

MATERIALS AND METHODS

Between July 2016 and December 2017, 68 patients visiting the emergency room with an underlying gynecologic malignancy were evaluated. Variables concerning underlying disease, invasive procedures, and laboratory and clinical parameters were analyzed. Patients were divided into three groups based on their blood and urine specimens (positive blood specimens, positive urine specimens, and no positive specimens; patients who had both positive blood and urine specimens were included in the group of positive blood specimens). Risk factors for surgical site infections, recent (<30 days) surgery, and chemotherapy were studied separately.

RESULTS

68 patients were included in the analysis. Mean age was 55.6 years (standard deviation 14.1). 44% of patients had ovarian cancer, 35% cervical cancer, 12% endometrial cancer, and 9% had other cancer types. In total, 96% of all patients had undergone surgery. Patients who had been treated with chemotherapy were at a higher risk of developing bloodstream infection (P=0.04; odds ratio (OR)=7.9). C reactive protein, bilirubin, and oxygen saturation (SO₂) were significantly different between patients with an underlying infection and those who had none. Only C reactive protein maintained its significance in a linear model, with a cut-off of 180 mg/L (linear regression, P=0.03; OR=4).

CONCLUSIONS

Chemotherapy is a risk factor for the development of bloodstream infections in patients with an underlying gynecologic malignancy; C reactive protein could be a useful tool in making this diagnosis.

Lung and Gut Microbiota as Potential Hidden Driver of Immunotherapy Efficacy in Lung Cancer

Lung cancer is one of the deadliest and most common malignancies in the world, representing one of the greatest challenges in cancer treatment. Immunotherapy is rapidly changing standard treatment schedule and outcomes for patients with advanced malignancies. However, several ongoing studies are still attempting to elucidate the biomarkers that could predict treatment response as well as the new strategies to improve antitumor immune system response ameliorating immunotherapy efficacy. The complex of bacteria, fungi, and other microorganisms, termed microbiota, that live on the epithelial barriers of the host, are involved in the initiation, progression, and dissemination of cancer. The functional role of microbiota has attracted an accumulating attention recently. Indeed, it has been demonstrated that commensal microorganisms are required for the maturation, education, and function of the immune system regulating the efficacy of immunotherapy in the anticancer response. In this review, we discuss some of the major findings depicting bacteria as crucial gatekeeper for the immune response against tumor and their role as driver of immunotherapy efficacy in lung cancer with a special focus on the distinctive role of gut and lung microbiota in the efficacy of immunotherapy treatment.

Antibiotic therapy and outcome from immune-checkpoint inhibitors

Sensitivity to immune checkpoint inhibitor (ICPI) therapy is governed by a complex interplay of tumor and host-related determinants. Epidemiological studies have highlighted that exposure to antibiotic therapy influences the probability of response to ICPI and predict for shorter patient survival across malignancies. Whilst a number of studies have reproducibly documented the detrimental effect of broad-spectrum antibiotics, the immune-biologic mechanisms underlying the association with outcome are poorly understood. Perturbation of the gut microbiota, an increasingly well-characterized factor capable of influencing ICPI-mediated immune reconstitution, has been indicated as a putative mechanism to explain the adverse effects attributed to antibiotic exposure in the context of ICPI therapy. Prospective studies are required to validate antibiotic-mediated gut perturbations as a mechanism of ICPI refractoriness and guide the development of strategies to overcome this barrier to an effective delivery of anti-cancer immunotherapy.

Chronic Stress, Inflammation, and Colon Cancer: A CRH System-Driven Molecular Crosstalk

Chronic stress is thought to be involved in the occurrence and progression of multiple diseases, via mechanisms that still remain largely unknown. Interestingly, key regulators of the stress response, such as members of the corticotropin-releasing-hormone (CRH) family of neuropeptides and receptors, are now known to be implicated in the regulation of chronic inflammation, one of the predisposing factors for oncogenesis and disease progression. However, an interrelationship between stress, inflammation, and malignancy, at least at the molecular level, still remains unclear. Here, we attempt to summarize the current knowledge that supports the inseparable link between chronic stress, inflammation, and colorectal cancer (CRC), by modulation of a cascade of molecular signaling pathways, which are under the regulation of CRH-family members expressed in the brain and periphery. The understanding of the molecular basis of the link among these processes may provide a step forward towards personalized medicine in terms of CRC diagnosis, prognosis and therapeutic targeting.

Rectal Cancer: 20% Risk Reduction Thanks to Dietary Fibre Intake. Systematic Review and Meta-Analysis

The aim of this systematic review and meta-analysis was to evaluate the association between dietary fibre intake and rectal cancer (RC) risk. In January 2019, a structured computer search on PubMed/Medline, Excerpta Medica dataBASE (EMBASE) and Scopus was performed for studies reporting the results of primary research evaluating dietary fibre intake in women and men as well as the risk of developing RC. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations were followed. Highest vs. lowest fibre concentrations was compared. The Egger test was used to estimate publication bias. Heterogeneity between studies was evaluated with I² statistics. The search strategy identified 912 papers, 22 of which were included in our meta-analysis. Having evaluated a total of 2,876,136 subjects, the results suggest a protective effect of dietary fibre intake on RC prevention. The effect Size (ES) was [0.77 (95% CI = 0.66–0.89), p-value = 0.001)]. Moderate statistical heterogeneity (Chi² = 51.36, df = 21, I² = 59.11%, p-value = 0.000) was found. However, no publication bias was found, as confirmed by Egger’s linear regression test (Intercept −0.21, t = −0.24, p = 0.816). The findings suggest that dietary fibre intake could be protective against RC, with a clinically relevant reduction of RC risk. Identifying preventive measures to avoid the development of RC, especially by following a healthy lifestyle including healthy diet, is pivotal.