Prebiotics Progress Shifts in the Intestinal Microbiome That Benefits Patients with Type 2 Diabetes Mellitus

Hypoglycemic medications that could be co-administered with prebiotics and functional foods can potentially reduce the burden of metabolic diseases such as Type 2 Diabetes Mellitus (T2DM). The efficacy of drugs such as metformin and sulfonylureas can be enhanced by the activity of the intestinal microbiome elaborated metabolites. Functional foods such as prebiotics (e.g., oligofructose) and dietary fibers can treat a dysbiotic gut microbiome by enhancing the diversity of microbial niches in the gut. These beneficial shifts in intestinal microbiome profiles include an increased abundance of bacteria such as Faecalibacterium prauznitzii, Akkermancia muciniphila, Roseburia species, and Bifidobacterium species. An important net effect is an increase in the levels of luminal SCFAs (e.g., butyrate) that provide energy carbon sources for the intestinal microbiome in cross-feeding activities, with concomitant improvement in intestinal dysbiosis with attenuation of inflammatory sequalae and improved intestinal gut barrier integrity, which alleviates the morbidity of T2DM. Oligosaccharides administered adjunctively with pharmacotherapy to ameliorate T2DM represent current plausible treatment modalities.

Probiotics and Commensal Bacteria Metabolites Trigger Epigenetic Changes in the Gut and Influence Beneficial Mood Dispositions

The effect of the intestinal microbiome on the gut-brain axis has received considerable attention, strengthening the evidence that intestinal bacteria influence emotions and behavior. The colonic microbiome is important to health and the pattern of composition and concentration varies extensively in complexity from birth to adulthood. That is, host genetics and environmental factors are complicit in shaping the development of the intestinal microbiome to achieve immunological tolerance and metabolic homeostasis from birth. Given that the intestinal microbiome perseveres to maintain gut homeostasis throughout the life cycle, epigenetic actions may determine the effect on the gut-brain axis and the beneficial outcomes on mood. Probiotics are postulated to exhibit a range of positive health benefits including immunomodulating capabilities. Lactobacillus and Bifidobacterium are genera of bacteria found in the intestines and so far, the benefits afforded by ingesting bacteria such as these as probiotics to people with mood disorders have varied in efficacy. Most likely, the efficacy of probiotic bacteria at improving mood has a multifactorial dependency, relying namely on several factors that include the agents used, the dose, the pattern of dosing, the pharmacotherapy used, the characteristics of the host and the underlying luminal microbial environment (e.g., gut dysbiosis). Clarifying the pathways linking probiotics with improvements in mood may help identify the factors that efficacy is dependent upon. Adjunctive therapies with probiotics for mood disorders could, through DNA methylation molecular mechanisms, augment the intestinal microbial active cohort and endow its mammalian host with important and critical co-evolutionary redox signaling metabolic interactions, that are embedded in bacterial genomes, and that in turn can enhance beneficial mood dispositions.

Letter on "Role of gut microbiome in immune regulation and immune checkpoint therapy of colorectal cancer"

Investigations that decipher the human microbiome have reformed the way medicine is focusing on bacteria. An interesting research review recently published in the journal of Digestive Diseases and Sciences conceivably linked adjunctive commensal intestinal bacteria with the capacity to modulate the immune microenvironment towards immune checkpoint inhibitor (ICIs) efficacy of cancer immunotherapy. Evidence has emerged that the intestinal microbiome can modulate outcomes to ICIs therapies via two major mechanisms, namely mechanisms that are antigen-specific (i.e., epitopes are shared between microbial and tumour antigens that can enhance or reduce anti-tumour immune responses) and those mechanisms that are antigen-independent (i.e., modulation of responses to ICIs by engaging innate and/or adaptive immune cells).

Is miR-223 Upregulation in Inflammatory Bowel Diseases a Protective Response?

Inflammatory bowel diseases (IBD) are characterized by chronic inflammation and damage of colonocytes with etiology of genetic, epigenetic and environmental factors. MicroRNA-223 (miR-223) has been found to be increased in both IBD patients and animal colitis models. However, contentious opinions relevant to the roles of miR-223 in IBD have been reported. Notwithstading that most studies have described that miR-223 has anti-inflammatory effects, several reports have progressed a pro-inflammatory view. In this review, we summarise both the anti-inflammatory and pro-inflammatory effects of miR-223 on key molecules in inflammatory responses in both animal models and in patients diagnosed with IBD and objectively discuss the possible basis for the discrepancies.

An exploratory study of the gut microbiota in major depression with anxious distress

OBJECTIVES

To explore differences in the diversity and composition of the gut microbiome between major depressive disorder (MDD) with and without anxious distress.

METHODS

The study comprised 117 participants (79 female, 36 male, 2 other, mean age 38.2 ± 13.4 years) with a current major depressive episode (MDE) with (n = 63) and without (n = 54) the anxious distress specifier. A clinical psychologist administered the structured clinical interview for the DSM-5-RV to confirm a diagnosis of depression. Participants provided stool samples which were immediately frozen and stored at -80 °C. These samples were analysed using the Illumina 16S Metagenomics sequencing protocol in which the sequencing primers target the V3 and V4 regions of the 16S rRNA gene. Participants also completed mental health questionnaires to assess severity of depression (BDI-II), generalized anxiety (GAD-7), and stress (PSS).

RESULTS

There were no significant group differences in α-diversity (Shannon's diversity Index; Simpson Index), richness (ACE; Chao1), (Pielou's) evenness, or beta diversity (Bray-Curtis dissimilarity index and weighted UniFrac distance) of gut bacteria. Significant group differences in the relative abundance of gut microbiota however were observed at each taxonomical level, including across 15 genera and 18 species.

LIMITATIONS

This was an exploratory study that needs to be replicated across larger samples and compared with a healthy control group.

CONCLUSIONS

The research contributes to knowledge of the depressive gut microbial profile unique to the anxious distress subtype of MDD.

Pilot clinical and pharmacokinetic study of Δ9-Tetrahydrocannabinol (THC)/Cannabidiol (CBD) nanoparticle oro-buccal spray in patients with advanced cancer experiencing uncontrolled pain

This pilot study aimed to assess the safety, tolerability, pharmacokinetics and exploratory analgesic effect of a novel water-soluble oro-buccal nanoparticle spray of a cannabis-based medicine (MDCNS-01) in patients with advanced incurable malignancy with unrelieved pain from opioid analgesic. The study was a non-blinded single arm 2 stage study. Stage I was a single escalating dose (n = 5) [2.5 mg Δ9-THC and 2.5 mg CBD) versus a 3-fold escalated dose. Stage II was an up-titrated dose in patients with advanced cancers and intractable pain (n = 25). During Stage I with an increased cannabis-based medicine dose, maximum observed plasma concentrations of cannabinoids were dose dependant. The water-soluble formulation in the current study resulted in a higher median (min, max) systemic exposure of Δ9-THC than CBD (AUC from 2.5 mg each of Δ9-THC and CBD, was 1.71 ng mL.h-1 (1.1, 6.6) and 0.65 ng mL.h-1 (0.49, 4.1), respectively). During stage II a subgroup of patients diagnosed with breast and prostate cancers with bone metastases, had the highest mean pain score improvement from baseline of 40% (unadjusted) and 33% (adjusted for rescue medication use). For all patients the most reported adverse events were mild or moderate drowsiness affecting 11 (44%) and 4 (6%) patients, respectively, and nausea and vomiting that affected 18 (72%) patients. The water-soluble cannabis-based medicine provided acceptable bioavailability for Δ9-THC/CBD, appeared safe and tolerable in advanced incurable cancers with uncontrolled pain with preliminary evidence of analgesic efficacy.

A randomized controlled trial assessing the safety and efficacy of palmitoylethanolamide for treating diabetic-related peripheral neuropathic pain

Background

Peripheral neuropathy is a common complication of diabetes. The management of the associated neuropathic pain remains difficult to treat.

Objective

This study explored the safety, tolerability and efficacy of a palmitoylethanolamide (PEA) formulation in treating diabetic-related peripheral neuropathic pain (PNP). Secondary outcomes included systemic inflammation, sleep and mood changes in patients diagnosed with type 1 and type 2 diabetes and PNP.

Design

This study was a single-centre, quadruple-blinded, placebo-controlled trial with 70 participants receiving 600 mg of PEA or placebo daily, for 8 weeks, with a 94% rate of study participation completion. Primary outcomes were neuropathic pain and specific pain types (the BPI-DPN and NPSI). The secondary outcomes were sleep quality (MOS sleep scale), mood (DASS-21), glucose metabolism and inflammation.

Results

There was a significant reduction (P ≤ 0.001) in BPI-DPN total pain and pain interference, NPSI total score and sub-scores, except for evoked pain (P = 0.09) in the PEA group compared with the placebo group. The MOS sleep problem index and sub-scores significantly improved (P ≤ 0.001). DASS-21 depression scores significantly reduced (P = 0.03), but not anxiety or stress scores. Interleukin-6 and elevated C-reactive protein levels significantly reduced in the PEA group (P = 0.05), with no differences in fibrinogen between groups (P = 0.78) at treatment completion. There were no changes in safety pathology parameters, and the treatment was well tolerated.

Conclusions

The study demonstrated that the PEA formulation reduced diabetic peripheral neuropathic pain and inflammation along with improving mood and sleep. Further studies on the mechanistic effectiveness of PEA as an adjunct medicine and as a monotherapy pain analgesic are warranted.

Clinical Trial Registration

Registry name: Australian New Zealand Clinical Trials Registry (ANZCTR), Registration number: ACTRN12620001302943, Registration link: https://anzctr.org.au/Trial/Registration/TrialReview.aspx?id=380826, Actual study start date: 20 November 2020.

The Role of the Gut-Lung Axis in COVID-19 Infections and Its Modulation to Improve Clinical Outcomes

The main entry point of SARS-CoV-2 is the respiratory tract and as such immune defence in this site determines if the virus will spill-over to the systemic circulation and circulate and infect other major organs. The first line of mucosal immune defence is composed of mucins, an epithelial barrier, and immune cells in the nasal cavity. The lung immune defence is carried out by numerous alveoli. The lung microbiota is a key factor in determining the efficacy of lung mucosal immunity protection. The intestinal microbiota has been demonstrated to affect the severity of COVID-19. Gut dysbiosis is involved in hyperinflammation and multiple organ failure through communications with multiple organs. The gut lung axis could be the earliest axis affected in COVID-19. Through the gut-lung axis, gut dysbiosis can affect the pathogenesis of the lung in COVID-19. In this review, we summarise the effects that gut dysbiosis can progress on the lung, and the lung microbiota. The possible mechanisms and approaches for modulation are discussed.

Tetrahydrocannabinol and cannabidiol medicines for chronic pain and mental health conditions

Combination tetrahydrocannabinol (THC)/cannabidiol (CBD) medicines or CBD-only medicines are prospective treatments for chronic pain, stress, anxiety, depression, and insomnia. THC and CBD increase signaling from cannabinoid receptors, which reduces synaptic transmission in parts of the central and peripheral nervous systems and reduces the secretion of inflammatory factors from immune and glial cells. The overall effect of adding CBD to THC medicines is to enhance the analgesic effect but counteract some of the adverse effects. There is substantial evidence for the effectiveness of THC/CBD combination medicines for chronic pain, especially neuropathic and nociplastic pain or pain with an inflammatory component. For CBD-only medication, there is substantial evidence for stress, moderate evidence for anxiety and insomnia, and minimal evidence for depression and pain. THC/CBD combination medicines have a good tolerability and safety profile relative to opioid analgesics and have negligible dependence and abuse potential; however, should be avoided in patients predisposed to depression, psychosis and suicide as these conditions appear to be exacerbated. Non-serious adverse events are usually dose-proportional, subject to tachyphylaxis and are rarely dose limiting when patients are commenced on a low dose with gradual up-titration. THC and CBD inhibit several Phase I and II metabolism enzymes, which increases the exposure to a wide range of drugs and appropriate care needs to be taken. Low-dose CBD that appears effective for chronic pain and mental health has good tolerability and safety, with few adverse effects and is appropriate as an initial treatment.

Intestinal Dysbiosis, the Tryptophan Pathway and Nonalcoholic Steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) progresses from simple steatosis to steatohepatitis (NASH), which may then progress to the development of cirrhosis and hepatocarcinoma. NASH is characterized by both steatosis and inflammation. Control of inflammation in NASH is a key step for the prevention of disease progression to severe sequalae. Intestinal dysbiosis has been recognized to be an important causal factor in the pathogenesis of NASH, involving both the accumulation of lipids and aggravation of inflammation. The effects of gut dysbiosis are mediated by adverse shifts of various intestinal commensal bacterial genera and their associated metabolites such as butyrate, tryptophan, and bile acids. In this review, we focus on the roles of tryptophan and its metabolites in NASH in association with intestinal dysbiosis and discuss possible therapeutic implications.

The intestinal microbiota and improving the efficacy of COVID-19 vaccinations

Most COVID-19 cases are mild or asymptomatic and recover well, suggesting that effective immune responses ensue, which successfully eliminate SARS-CoV-2 viruses. However, a small proportion of patients develop severe COVID-19 with pathological immune responses. This indicates that a strong immune system balanced with anti-inflammatory mechanisms is critical for the recovery from SARS-CoV-2 infections. Many vaccines against SARS-CoV-2 have now been developed for eliciting effective immune responses to protect from SARS-CoV-2 infections or reduce the severity of the disease if infected. Although uncommon, serious morbidity and mortality have resulted from both COVID-19 vaccine adverse reactions and lack of efficacy, and further improvement of efficacy and prevention of adverse effects are urgently warranted. Many factors could affect efficacy of these vaccines to achieve optimal immune responses. Dysregulation of the gut microbiota (gut dysbiosis) could be an important risk factor as the gut microbiota is associated with the development and maintenance of an effective immune system response. In this narrative review, we discuss the immune responses to SARS-CoV-2, how COVID-19 vaccines elicit protective immune responses, gut dysbiosis involvement in inefficacy and adverse effects of COVID-19 vaccines and the modulation of the gut microbiota by functional foods to improve COVID-19 vaccine immunisations.

Altered gut microbial metabolites could mediate the effects of risk factors in Covid-19

Coronavirus disease 2019 (Covid-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, is now pandemic. While most Covid-19 patients will experience mild symptoms, a small proportion will develop severe disease, which could be fatal. Clinically, Covid-19 patients manifest fever with dry cough, fatigue and dyspnoea, and in severe cases develop into acute respiratory distress syndrome (ARDS), sepsis and multi-organ failure. These severe patients are characterized by hyperinflammation with highly increased pro-inflammatory cytokines including IL-6, IL-17 and TNF-alpha as well as C-reactive protein, which are accompanied by decreased lymphocyte counts. Clinical evidence supports that gut microbiota dysregulation is common in Covid-19 and plays a key role in the pathogenesis of Covid-19. In this narrative review, we summarize the roles of intestinal dysbiosis in Covid-19 pathogenesis and posit that the associated mechanisms are being mediated by gut bacterial metabolites. Based on this premise, we propose possible clinical implications. Various risk factors could be causal for severe Covid-19, and these include advanced age, concomitant chronic disease, SARS-CoV-2 infection of enterocytes, use of antibiotics and psychological distress. Gut dysbiosis is associated with risk factors and severe Covid-19 due to decreased commensal microbial metabolites, which cause reduced anti-inflammatory mechanisms and chronic low-grade inflammation. The preconditioned immune dysregulation enables SARS-CoV-2 infection to progress to an uncontrolled hyperinflammatory response. Thus, a pre-existing gut microbiota that is diverse and abundant could be beneficial for the prevention of severe Covid-19, and supplementation with commensal microbial metabolites may facilitate and augment the treatment of severe Covid-19.

A pilot safety, tolerability and pharmacokinetic study of an oro-buccal administered cannabidiol-dominant anti-inflammatory formulation in healthy individuals: a randomized placebo-controlled single-blinded study

BACKGROUND

The cannabis plant presents a complex biochemical unit of over 500 constituents of which 70 or more molecules have been classified as cannabinoids binding to cannabinoid receptors. The study aimed to investigate the safety, tolerability, and preliminary pharmacokinetics of a nanoparticle CBD formulation.

METHODS

The cannabis-based medicine was elaborated with a micellular technology, to produce a water-soluble nanoparticle CBD-dominant anti-inflammatory cannabis medicine (MDCNB-02). On day one, 12 participants administered 2 sprays and on day 2 administered 6 sprays to alternating right and left cheeks [18 mg of CBD and 0.72 mg of THC]. Four other participants administered 2 and 6 sprays on days 1 and 2, respectively of a nanoparticle placebo.

RESULTS

The study met the primary outcomes of safety, tolerability, and preliminary pharmacokinetics of a standardized CBD-dominant anti-inflammatory extract for oro-buccal administration. Bioavailability of a 6 mg and 18 mg dose of CBD (median IQR) was 0.87 and 8.9 ng h mL^-1, respectively. The maximum concentration of CBD for the low and high doses administered once per day occurred at 60 min for both concentrations. The median half-life of the 6 mg and 18 mg CBD dose was 1.23 and 5.45 h, respectively. The apparent clearance of CBD was 115 and 34 L min^-1 for a 6 mg and 18 mg dose, respectively.

CONCLUSION

The oro-buccal nanoparticle formulation achieved plasma concentrations that were largely comparable to other commercial and investigated formulations relative to the concentrations administered. Moreover, there were no reports of adverse effects associated with unfavorable inflammatory sequalae.

Modulation of Gut Microbiota for the Prevention and Treatment of COVID-19

The gut microbiota is well known to exert multiple benefits on human health including protection from disease causing pathobiont microbes. It has been recognized that healthy intestinal microbiota is of great importance in the pathogenesis of COVID-19. Gut dysbiosis caused by various reasons is associated with severe COVID-19. Therefore, the modulation of gut microbiota and supplementation of commensal bacterial metabolites could reduce the severity of COVID-19. Many approaches have been studied to improve gut microbiota in COVID-19 including probiotics, bacterial metabolites, and prebiotics, as well as nutraceuticals and trace elements. So far, 19 clinical trials for testing the efficacy of probiotics and synbiotics in COVID-19 prevention and treatment are ongoing. In this narrative review, we summarize the effects of various approaches on the prevention and treatment of COVID-19 and discuss associated mechanisms.

Gut Microbiota Metabolites in NAFLD Pathogenesis and Therapeutic Implications

Gut microbiota dysregulation plays a key role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) through its metabolites. Therefore, the restoration of the gut microbiota and supplementation with commensal bacterial metabolites can be of therapeutic benefit against the disease. In this review, we summarize the roles of various bacterial metabolites in the pathogenesis of NAFLD and their therapeutic implications. The gut microbiota dysregulation is a feature of NAFLD, and the signatures of gut microbiota are associated with the severity of the disease through altered bacterial metabolites. Disturbance of bile acid metabolism leads to underactivation of bile acid receptors FXR and TGR5, causal for decreased energy expenditure, increased lipogenesis, increased bile acid synthesis and increased macrophage activity. Decreased production of butyrate results in increased intestinal inflammation, increased gut permeability, endotoxemia and systemic inflammation. Dysregulation of amino acids and choline also contributes to lipid accumulation and to a chronic inflammatory status. In some NAFLD patients, overproduction of ethanol produced by bacteria is responsible for hepatic inflammation. Many approaches including probiotics, prebiotics, synbiotics, faecal microbiome transplantation and a fasting-mimicking diet have been applied to restore the gut microbiota for the improvement of NAFLD.

An oro-buccal nanoparticle delivered cannabis medicine for pain management in cancer: A clinical trial in progress

TPS12127

Background: Cannabinoid molecules derived from Cannabis sativa L. have been posited to ameliorate conditions, including pain, chemotherapy induced nausea and multiple sclerosis associated spasticity. The clinical use of cannabinoids refers to a wide variety of formulations and extracts that may contain different active ingredients and adulterants as well as inter batch variability. Novel matrix formulations (e.g., water-soluble nanoparticles) for cannabis delivery may add further efficacy and tolerability to standard routes of administration (e.g., oral / gastrointestinal, inhaled, sublingual). This is further emphasized by the dysbiotic effects on the intestinal microbiome reported for oral formulations of medicinal cannabis, and which resulted in reduced efficacy. Similar results have been reported for other psychotropic compounds, such as alcohol and nicotine. Therapeutic use of cannabinoid formulations may be mode of delivery dependent in order to achieve safe, tolerable and effective doses. Methods: A water soluble oro-buccal nanoparticle spray with a racemic 1:1 mixture of Delta9Tetrahydrocannabinol (D9THC) and Cannabidiol (CBD), which bypasses the gastrointestinal system and first pass metabolism by accessing the systemic circulation via the facial lymphatics system, was investigated in patients with advanced cancer and unrelieved pain in a single ascending dose and multiple ascending dose in a first-in-human study. Results: The THC / CBD combination delivered as a submicron particle demonstrated safety, tolerability and a pharmacokinetic profile suitable for maintenance analgesic therapy. Preliminary analysis found an overall (n = 25) improvement in pain scores, especially in the subgroup of patients with bone metastases (n = 8), who obtained a greater than 30% average reduction in pain severity. 1 Clinical trial information: ACTRN12617001480370 .

The gallbladder and vermiform appendix influence the assemblage of intestinal microorganisms

Surgical procedures for the symptomatic removal of the gallbladder and the vermiform appendix have been posited to adversely shift the assemblage of the intestinal microbiome increasing the risk of disease. The associated mechanisms have been linked with dysbiosis of the gut microbiota. Cholecystectomy causes changes of bile acid compositions and bile secretion patterns as bile acids interact with the intestinal microbiota in a bidirectional capacity. An appendectomy precludes the further recolonization of the proximal colon with a commensal biofilm that could maintain a stable intestinal microbiome. Epidemiological studies indicate that there is an increased risk of disease rather than causality following a cholecystectomy and appendectomy. This narrative review summarizes studies that report on the role that bile salts and the appendix, contribute to the assemblage of the intestinal microbiome in health and disease.

A Double-Blind Randomized Placebo-Controlled Study Assessing the Safety, Tolerability and Efficacy of a Herbal Medicine Containing Pycnogenol Combined with Papain and Aloe vera in the Prevention and Management of Pre-Diabetes

Background: Herbal medicines present attractive options to patients with chronic diseases. Undertaking clinical studies with patients presenting with symptomless pre-T2D can lead to significant limitations. Methods: A 12-week randomized double-blind placebo-controlled clinical study was conducted that investigated the safety and efficacy of an herbal formulation administered orally for the treatment of pre-type 2 diabetes (pre-T2D). Results: A numerically greater proportion of subjects in the interventional arm had impaired fasting glucose (IFG) at week 12 compared to the control arm (71.0% vs. 69.0%, p = 0.75). Fewer participants had impaired glucose tolerance (IGT) at 12 weeks in the intervention arm compared to the control arm (unadjusted 58.3% vs. 66.7%, p = 0.65; adjusting for baseline IGT, p = 0.266). In a subgroup analysis, subjects with a baseline fasting plasma glucose (FPG) level in the range of 6.1-6.9 mmol/L demonstrated a non-significant lower proportion of IFG at week 12 in the intervention arm compared to the control arm (60.0% vs. 41.7% p = 0.343). Total blood cholesterol and triglyceride levels remained unchanged from baseline to week 12 in both treatment groups. Conclusions: This study suggests that a polyherbal medicine was not effective for reducing the metabolic markers associated with pre-T2D over a 12-week period. Therefore, larger studies with well-defined endpoints and of longer duration are warranted.

The Role of Butyrate in Attenuating Pathobiont-Induced Hyperinflammation

An excessive hyperinflammatory response-caused septic shock is a major medical problem that is associated with pathogenic bacterial infections leading to high mortality rates. The intestinal microbiota and the associated elaborated metabolites such as short chain fatty acid butyrate have been shown to relieve pathogenic bacterial-caused acute inflammation. Butyrate can down-regulate inflammation by inhibiting the growth of pathobionts, increasing mucosal barrier integrity, encouraging obligate anaerobic bacterial dominance and decreasing oxygen availability in the gut. Butyrate can also decrease excessive inflammation through modulation of immune cells such as increasing functionalities of M2 macrophages and regulatory T cells and inhibiting infiltration by neutrophils. Therefore, various approaches can be used to increase butyrate to relieve pathogenic bacterial-caused hyperinflammation. In this review we summarize the roles of butyrate in attenuating pathogenic bacterial-caused hyperinflammatory responses and discuss the associated plausible mechanisms.

Zinc deficits, mucositis, and mucosal macrophage perturbation: is there a relationship?

PURPOSE OF REVIEW

Mucositis is a common and therapy-limiting adverse effect of cancer treatments including radiotherapy, chemotherapy, and immunotherapy. The optimal zinc formulation, dosage, and timing of administration warrant further research as does the efficacious prevention of febrile mucositis that predisposes to febrile neutropenia.

RECENT FINDINGS

Metaanalyses concluded that zinc sulfate failed to significantly reduce the incidence or severity of chemotherapy-induced oral mucositis, whereas polaprezinc was associated with a significant reduction. Three new trials were published in 2018. The first trial found that zinc sulfate reduced the incidence and severity of chemotherapy-induced oral mucositis. The second reported that polaprezinc reduced oral mucositis in pediatric patients receiving high-dose chemotherapy for hematopoietic stem cell transplantation. The third trial demonstrated efficacy for a zinc lozenge for postoperative sore throat induced by an endotracheal intubation.

SUMMARY

Zinc deficits, dietary or induced by cancer, are common in patients with cancer. Febrile mucositis may better describe the condition linking mucositis with febrile neutropenia. Febrile mucositis disrupts treatment and may be life-threatening. A paradigm shift is needed for a more comprehensive understanding of febrile mucositis. Zinc effects on the thymic immunological network and T lymphocytes during chemoradiotherapy regimens also warrant further investigation.

Mitochondria could be a potential key mediator linking the intestinal microbiota to depression

The intestinal microbiota has been reported to affect depression, a common mental condition with severe health-related consequences. However, what mediates the effect of the intestinal microbiota on depression has not been well elucidated. We summarize the roles of the mitochondria in eliciting beneficial effects on the gut microbiota to ameliorate symptoms of depression. It is well known that mitochondria play a key role in depression. An important pathogenic factor, namely inflammatory response, may adversely impact mitochondrial functionality to maintain cellular homeostasis. Dysfunction of mitochondria not only affects neuronal function but also reduces neuron cell numbers. We posit that the intestinal microbiota could affect neuronal mitochondrial function through short-chain fatty acids such as butyrate. Brain inflammatory processes could also be affected through the modulation of gut permeability and blood lipopolysaccharide levels. Aberrant mitochondria functionality coupled to adverse cellular homeostasis could be a key mediator for the effect of the intestinal microbiota on the progression of depression.

Gut Dysbiosis and the Intestinal Microbiome: Streptococcus thermophilus a Key Probiotic for Reducing Uremia

In the intestines, probiotics can produce antagonistic effects such as antibiotic–like compounds, bactericidal proteins such as bacteriocins, and encourage the production of metabolic end products that may assist in preventing infections from various pathobionts (capable of pathogenic activity) microbes. Metabolites produced by intestinal bacteria and the adoptions of molecular methods to cross-examine and describe the human microbiome have refreshed interest in the discipline of nephology. As such, the adjunctive administration of probiotics for the treatment of chronic kidney disease (CKD) posits that certain probiotic bacteria can reduce the intestinal burden of uremic toxins. Uremic toxins eventuate from the over manifestation of glucotoxicity and lipotoxicity, increased activity of the hexosamine and polyol biochemical and synthetic pathways. The accumulation of advanced glycation end products that have been regularly associated with a dysbiotic colonic microbiome drives the overproduction of uremic toxins in the colon and the consequent local pro-inflammatory processes. Intestinal dysbiosis associated with significant shifts in abundance and diversity of intestinal bacteria with a resultant and maintained uremia promoting an uncontrolled mucosal pro-inflammatory state. In this narrative review we further address the efficacy of probiotics and highlighted in part the probiotic bacterium Streptococcus thermophilus as an important modulator of uremic toxins in the gut of patients diagnosed with chronic kidney disease. In conjunction with prudent nutritional practices it may be possible to prevent the progression of CKD and significantly downregulate mucosal pro-inflammatory activity with the administration of probiotics that contain S. thermophilus.

Interaction of gut microbiota with dysregulation of bile acids in the pathogenesis of nonalcoholic fatty liver disease and potential therapeutic implications of probiotics

The intestinal microbiota is now recognised to play key roles in health due to its involvement in many aspects of human physiology. Disturbance in gut microbiota (dysbiosis) is thus associated with many diseases including nonalcoholic fatty liver disease (NAFLD) which includes nonalcoholic fatty liver and nonalcoholic steatohepatitis. The mechanisms for the effect of dysbiosis in NAFLD pathogenesis are not completely elucidated. Many explanations have been proposed to trigger dysbiosis, leading to NAFLD including inflammation, ethanol produced by the gut bacteria and lipotoxicity. Recently the roles of bile acids and nuclear receptors are highly regarded. It is well known that gut microbes produce enzymes that convert primary bile acids into secondary bile acids in the intestines. Several studies have demonstrated that disturbance of the intestinal microbiota leads to decreased synthesis of secondary bile acids, which in turn decreases activation of nuclear receptors such as farnesoid X receptor (FXR), pregnane X receptor, Takeda G-protein-coupled bile acid protein 5 and vitamin D receptor. These receptors are important in energy regulation and their dysregulation can cause NAFLD. Therefore, stimulation of nuclear receptors especially FXR has been extensively explored for the amelioration of NAFLD. However, paradoxical effects of nuclear receptor activation are a major problem for the clinical application of nuclear receptor stimuli. We further posit that microbiome restoration could be an alternative approach for the treatment of NAFLD. Several gut bacteria are now known to be involved in bile acid metabolism. It will be necessary to identify which one/ones is/are feasible. Careful selection of commensal bacteria for probiotics may lead to an effective therapy for NAFLD.

Immunological Tolerance and Function: Associations Between Intestinal Bacteria, Probiotics, Prebiotics, and Phages

Post-birth there is a bacterial assault on all mucosal surfaces. The intestinal microbiome is an important participant in health and disease. The pattern of composition and concentration of the intestinal microbiome varies greatly. Therefore, achieving immunological tolerance in the first 3-4 years of life is critical for maintaining health throughout a lifetime. Probiotic bacteria are organisms that afford beneficial health effects to the host and in certain instances may protect against the development of disease. The potential benefits of modifying the composition of the intestinal microbial cohort for therapeutic benefit is evident in the use in high risks groups such as premature infants, children receiving antibiotics, rotavirus infections in non-vaccinated children and traveler's diarrhea in adults. Probiotics and prebiotics are postulated to have immunomodulating capabilities by influencing the intestinal microbial cohort and dampening the activity of pathobiont intestinal microbes, such as Klebsiella pneumonia and Clostridia perfringens. Lactobacilli and Bifidobacteria are examples of probiotics found in the large intestine and so far, the benefits afforded to probiotics have varied in efficacy. Most likely the efficacy of probiotic bacteria has a multifactorial dependency, namely on a number of factors that include agents used, the dose, the pattern of dosing, and the characteristics of the host and the underlying luminal microbial environment and the activity of bacteriophages. Bacteriophages, are small viruses that infect and lyse intestinal bacteria. As such it can be posited that these viruses display an effective local protective control mechanism for the intestinal barrier against commensal pathobionts that indirectly may assist the host in controlling bacterial concentrations in the gut. A co-operative activity may be envisaged between the intestinal epithelia, mucosal immunity and the activity of bacteriophages to eliminate pathobiots, highlighting the potential role of bacteriophages in assisting with maintaining intestinal homeostasis. Hence bacteriophage local control of inflammation and immune responses may be an additional immunological defense mechanism that exploits bacteriophage-mucin glycoprotein interactions that controls bacterial diversity and abundance in the mucin layers of the gut. Moreover, and importantly the efficacy of probiotics may be dependent on the symbiotic incorporation of prebiotics, and the abundance and diversity of the intestinal microbiome encountered. The virome may be an important factor that determines the efficacy of some probiotic formulations.

The role of adjuvant probiotics to attenuate intestinal inflammatory responses due to cancer treatments

Chemotherapy and radiotherapy treatment regimens for gastrointestinal, peritoneal and pelvic tumours can disrupt the intestinal microbiome and intestinal epithelia. Such disturbances can provoke symptoms such as diarrhoea, nausea and vomiting. Chemotherapy and radiotherapy induced gastrointestinal toxicity aggravating intestinal microbiome dysbiosis is postulated to adversely alter the intestinal microbiome, with a consequent induced pro-inflammatory effect that disrupts the intestinal microbiome-epithelia-mucosal immunity axis. Although not widely recognised, the intestinal mucosa is the largest and most densely and dynamically populated immune-environment. Cancer treatment adverse effects that affect intestinal and mucosal cells inadvertently target and disrupt resident intestinal macrophages, the cells that marshal immune activity in the intestinal mucosa by shaping pro-inflammatory and anti-inflammatory activities to control and eradicate infectious insults and maintain local homeostasis. Pathobionts (bacteria capable of pathogenic pro-inflammatory activity) and noxious environmental and bacterial antigens use the intestinal epithelia and gap junctions as a point of entry into the systemic circulation. This translocation movement promotes toxic sequelae that obstruct intestinal macrophage functions resulting in uncontrolled local and systemic pro-inflammatory activity, loss of phagocytic function and loss of expression of tight junction proteins. Probiotic bacteria as an adjunctive treatment shows efficacy in ameliorating enteropathies such as mucositis/diarrhoea resulting from chemotherapy or radiotherapy regimens. As such we posit that an important benefit that warrants a further focused research effort is the administration of adjuvant probiotics to help reduce the incidence of febrile neutropenia.

Adjunctive Treatments for the Prevention of Chemotherapy- and Radiotherapy-Induced Mucositis

Background: Chemoradiotherapy-associated mucositis can manifest as pain, inflammation, dysphagia, diarrhea, weight loss, rectal bleeding, and infection. Mucositis is a major dose-limiting side effect of chemotherapy, affecting nutritional intake and oral and intestinal function. Despite several interventions being available, there is a need for safe and effective preventative and treatment options for treatment-induced mucositis. The goals of this review are to discuss interventions based on foods and natural products and present the research to date. Methods: A narrative literature review identified 60 clinical studies examining various nutritional compounds and 20 examining probiotics. 9 studies on probiotics for the prevention of diarrhea were also assessed on methodological quality and limitations identified. Results: Several compounds have been posited as useful adjuvants for cancer treatment–related mucositis. Probiotics demonstrate efficacy for the prevention and treatment of chemoradiotherapy-induced gastrointestinal toxicity without significant side effects. Glutamine and activated charcoal were reported to reduce chemotherapy-induced diarrhea but not radiation-induced intestinal mucositis. Honey has been reported to decrease treatment interruptions, weight loss, and delays the onset of oral mucositis. Zinc, glutamine, and topical vitamin E were demonstrated efficacy for oral mucositis. Conclusion: There is plausible clinical evidence for the administration of several adjunctive treatments for the prevention and treatment of mucositis. Probiotics were reported to reduce the burden of intestinal mucositis and treatment-induced diarrhea. Activated charcoal and glutamine are beneficial for chemotherapy-induced diarrhea, whereas the administration of honey, zinc, and glutamine reduce the risk of developing oral mucositis during chemotherapy or radiotherapy.

Inflammation-Modulating Effect of Butyrate in the Prevention of Colon Cancer by Dietary Fiber

The intestinal microbiota plays key roles in human health, and adverse dysbiosis shifts of the microbiota have been associated with chronic diseases, including large bowel cancer. High-fiber diets may reduce the risk for large bowel cancer in association with gut microbiota modulation and butyrate production. Butyrate can inhibit histone deacetylases and associated signaling pathways in cultured cancer cells, promoting cancer cell apoptosis. However, butyrate has prevented colon cancer through the regulation of immune homeostasis rather than histone deacetylases inhibition. It could be important to further examine the pathways of how butyrate encourages immune system changes. We posited that butyrate-activated T-regulatory cells block proinflammatory T cells and thus reduce proinflammatory cytokine production; these cytokines increase cell proliferation and cell survival, the 2 most important cancer cell characteristics. Butyrate can exert anticancer effects through inhibition of multiple signaling pathways. It is possible that a low concentration of butyrate could modulate the immune system before other pathways to exert an anticancer effect. Increasing the concentration of butyrate in the intestines may produce a synergistic inhibitory signaling pathway response and an anti-inflammatory effect.

Correction: Vitetta, L.; et al. Adjuvant Probiotics and the Intestinal Microbiome: Enhancing Vaccines and Immunotherapy Outcomes. Vaccines 2017, 5, 50

The authors wish to make the following corrections to this paper due to a typesetting error in the conclusion of this article which was recently published in Vaccines.

Indoxyl Sulfate Induces Apoptosis and Hypertrophy in Human Kidney Proximal Tubular Cells

Indoxyl sulfate (IS) is a protein-bound uremic toxin that accumulates in patients with declining kidney function. Although generally thought of as a consequence of declining kidney function, emerging evidence demonstrates direct cytotoxic role of IS on endothelial cells and cardiomyocytes, largely through the expression of pro-inflammatory and pro-fibrotic factors. The direct toxicity of IS on human kidney proximal tubular epithelial cells (PTECs) remains a matter of debate. The current study explored the effect of IS on primary cultures of human PTECs and HK-2, an immortalized human PTEC line. Pathologically relevant concentrations of IS induced apoptosis and increased the expression of the proapoptotic molecule Bax in both cell types. IS impaired mitochondrial metabolic activity and induced cellular hypertrophy. Furthermore, statistically significant upregulation of pro-fibrotic (transforming growth factor-β, fibronectin) and pro-inflammatory molecules (interleukin-6, interleukin-8, and tumor necrosis factor-α) in response to IS was observed. Albumin had no influence on the toxicity of IS. The results of this study suggest that IS directly induced a pro-inflammatory and pro-fibrotic phenotype in proximal tubular cells. In light of the associated apoptosis, hypertrophy, and metabolic dysfunction, this study demonstrates that IS may play a role in the progression of chronic kidney disease.

Intestinal Microbiome Shifts, Dysbiosis, Inflammation, and Non-alcoholic Fatty Liver Disease

Adverse fluctuations in the distribution of the intestinal microbiome cohort has been associated with the onset of intra- and extra-intestinal inflammatory conditions, like the metabolic syndrome (MetS) and it's hepatic manifestation, non-alcoholic fatty liver disease (NAFLD). The intestinal microbial community of obese compared to lean subjects has been shown to undergo configurational shifts in various genera, including but not limited to increased abundances of Prevotella, Escherichia, Peptoniphilus, and Parabacteroides and decreased levels of Bifidobacteria, Roseburia, and Eubacteria genera. At the phylum level, decreased Bacteroidetes and increased Firmicutes have been reported. The intestinal microbiota therefore presents an important target for designing novel therapeutic modalities that target extra-intestinal inflammatory disorders, such as NAFLD. This review hypothesizes that disruption of the intestinal-mucosal macrophage interface is a key factor in intestinal-liver axis disturbances. Intestinal immune responses implicated in the manifestation, maintenance and progression of NAFLD provide insights into the dialogue between the intestinal microbiome, the epithelia and mucosal immunity. The pro-inflammatory activity and immune imbalances implicated in NAFLD pathophysiology are reported to stem from dysbiosis of the intestinal epithelia which can serve as a source of hepatoxic effects. We posit that the hepatotoxic consequences of intestinal dysbiosis are compounded through intestinal microbiota-mediated inflammation of the local mucosa that encourages mucosal immune dysfunction, thus contributing important plausible insight in NAFLD pathogenesis. The administration of probiotics and prebiotics as a cure-all remedy for all chronic diseases is not advocated, instead, the incorporation of evidence based probiotic/prebiotic formulations as adjunctive modalities may enhance lifestyle modification management strategies for the amelioration of NAFLD.