New insights into the impact of the intestinal microbiota on health and disease: a symposium report

Effects of probiotic supplementation on performance of resistance and aerobic exercises: a systematic review

CONTEXT

Strenuous exercise may lead to negative acute physiological effects that can impair athletic performance. Some recent studies suggest that probiotic supplementation can curtail these effects by reducing the permeability of the intestinal barrier, yet results are inconsistent.

OBJECTIVE

The aim of this systematic review is to assess the effects of probiotic supplementation on athletic performance.

DATA SOURCES

The PubMed/MEDLINE, Cochrane, and Scopus databases were searched for articles that assessed the effects of probiotic supplementation on athletic performance.

DATA EXTRACTION THIS SYSTEMATIC REVIEW IS REPORTED ACCORDING TO

PRISMA guidelines. Risk of bias was assessed through the Cochrane RoB 2.0 tool. Seventeen randomized clinical trials assessing athletic performance as the primary outcome were included. In total, 496 individuals (73% male) comprising athletes, recreationally trained individuals, and untrained healthy individuals aged 18 to 40 years were investigated.

DATA ANALYSIS

Three studies showed an increase or an attenuation of aerobic performance (decline in time to exhaustion on the treadmill) after supplementation with probiotics, while 3 found an increase in strength. However, most studies (n = 11) showed no effect of probiotic consumption on aerobic performance (n = 9) or muscular strength (n = 2). The most frequently used strain was Lactobacillus acidophilus, used in 2 studies that observed positive results on performance. Studies that used Lactobacillus plantarum TK10 and Lactobacillus plantarum PS128 also demonstrated positive effects on aerobic performance and strength, but they had high risk of bias, which implies low confidence about the actual effect of treatment.

CONCLUSION

There is not enough evidence to support the hypothesis that probiotics can improve performance in resistance and aerobic exercises. Further well-controlled studies are warranted.

Does Multi-Strain Probiotic Supplementation Impact the Effort Capacity of Competitive Road Cyclists?

(1) Background: The aim of this study was to assess the impact of multi-strain probiotic supplementation on the physical capacity and selected health indicators related to the exercise capacity of competitive road cyclists such as body composition, markers of intestinal permeability, pro- and anti-inflammatory markers, and anti-/pro-oxidant potential. (2) Methods: The group comprised 26 competitive road cyclists aged between 18 and 26. The study was a 4-month double-blind, random-assignment, parallel-group, and placebo-controlled trial. The measurements of physical capacity in the exercise tests of the anaerobic Wingate test (the level of total work volume, maximal anaerobic power, average power per revolution, mean time to achieve maximal anaerobic power, and time to maintain maximal anaerobic power) and the aerobic test using a cycle ergometer (maximum oxygen uptake, exercise duration, maximum load power, and maximal heart rate) were repeated after one, three, and four months. (3) Results: The probiotic supplementation resulted in increased levels of the relative magnitude of maximal oxygen uptake (65.28 vs. 69.18), the duration of training until failure (14.35 vs. 15.65), the load on the ergometer (5.11 vs. 5.36), and the degree of decrease in heart rate (193.3 vs. 188.6) together with a feeling of less discomfort during the exercise test (Borg scale) (19.38 vs. 18.43), confirming the beneficial effect of probiotics on the cyclists' aerobic capacity during exercise. The probiotic supplementation produces no effects on the anaerobic capacity and body composition of the athletes, except for an observed increase in muscle mass. The concentration of zonulin in the stool mass decreased as a result of the probiotic therapy (81.2 vs. 25.21), and α1-atitrypsin was maintained at a similar level during the experiment (0.95 vs. 1.05), indicating a sealing of the intestinal barrier and beneficial changes in the cyclists' intestinal function. The supplementation resulted in a reduction in the concentrations of: tumor necrosis factor TNF-α after the aerobic (13.88 vs. 9.75) and anaerobic tests (8.54 vs. 6.8), IL-6 before (1.2 vs. 0.86) and after the anaerobic test (1.47 vs. 0.97), IL-10 before the anaerobic test (0.70 vs. 0.44), and the total oxidative status (TOS) of the blood plasma before (663.7 vs. 484.6) and after the anaerobic test (643.1 vs. 435.9). (4) Conclusions: The probiotic supplementation resulted in increased levels of the cyclists' aerobic capacity and their maintenance of anaerobic capacity and positively affected selected health indicators related to the exercise capacity of competitive road cyclists.

The Potential of Honey as a Prebiotic Food to Re-engineer the Gut Microbiome Toward a Healthy State

Honey has a long history of use for the treatment of digestive ailments. Certain honey types have well-established bioactive properties including antibacterial and anti-inflammatory activities. In addition, honey contains non-digestible carbohydrates in the form of oligosaccharides, and there is increasing evidence from in vitro, animal, and pilot human studies that some kinds of honey have prebiotic activity. Prebiotics are foods or compounds, such as non-digestible carbohydrates, that are used to promote specific, favorable changes in the composition and function of the gut microbiota. The gut microbiota plays a critical role in human health and well-being, with disturbances to the balance of these organisms linked to gut inflammation and the development and progression of numerous conditions, such as colon cancer, irritable bowel syndrome, obesity, and mental health issues. Consequently, there is increasing interest in manipulating the gut microbiota to a more favorable balance as a way of improving health by dietary means. Current research suggests that certain kinds of honey can reduce the presence of infection-causing bacteria in the gut including Salmonella, Escherichia coli, and Clostridiodes difficile, while simultaneously stimulating the growth of potentially beneficial species, such as Lactobacillus and Bifidobacteria. In this paper, we review the current and growing evidence that shows the prebiotic potential of honey to promote healthy gut function, regulate the microbial communities in the gut, and reduce infection and inflammation. We outline gaps in knowledge and explore the potential of honey as a viable option to promote or re-engineer a healthy gut microbiome.

Probiotics/Synbiotics to Reduce Infectious Complications after Colorectal Surgery: A Systematic Review and Meta-Analysis of Randomised Controlled Trials

Aim: The aims of this systematic review and meta-analysis were to assess to what extent probiotics/synbiotics reduce infectious complications after colorectal surgery and whether probiotics or synbiotics should be considered as perioperative measures preventing or reducing infectious complications after CRS and should be included in enhanced recovery programmes (ERP). Secondary aims were to answer practical questions precisely on the best formulation and the type and timing of probiotics or synbiotics in CRS. Method: This systematic review and quantitative meta-analysis were conducted in accordance with PRISMA 2020 guidelines. Inclusion criteria were randomised trials comparing perioperative probiotics/synbiotics with a placebo or standard care in elective colorectal surgery. Exclusion criteria were non-randomised trials. Overall infectious complications and surgical site infections (SSIs including both deep abdominal infections and wound (skin or under the skin) infections) were the primary outcomes. Secondary outcomes were pulmonary and urinary infections, wound infections, and anastomotic leaks. The databases consulted were Medline, Cochrane Database of Systematic Reviews, Scopus, and Clinical Trials Register. Risk of bias was assessed according to the GRADE approach. The analysis calculated the random effects estimates risk ratio (RR) for each outcome. Results: 21 trials were included; 15 evaluated probiotics, and 6 evaluated synbiotics. There were significantly fewer infectious complications (risk ratio (RR) 0.59 [0.47–0.75], I² = 15%) and fewer SSI (RR 0.70 [0.52–0.95], I² = 0%) in the probiotic or synbiotic group. There were also significantly fewer pulmonary infections (RR 0.35 [0.20–0.63]) and urinary infections RR 0.41 [0.19–0.87]) as opposed to anastomotic leaks (RR 0.83 [0.47–1.48]) and wound infections (RR 0.74 [0.53–1.03]). Sensitivity analyses showed no significant difference between probiotics and synbiotics in reducing postoperative infections (RR 0.55 [0.42–0.73] versus RR 0.69 [0.42–1.13], p = 0.46). Conclusions: Based on the finding of this study, probiotics/synbiotics reduce infectious complications after colorectal surgery. The effect size was more pronounced for pulmonary and urinary infections. From a practical aspect, some of the questions related to formulations and duration of probiotics or synbiotics need to be answered before including them definitively in enhanced recovery after colorectal surgery programmes.

The effect of pro/synbiotics on postoperative infections in colorectal cancer patients: A systematic review and meta-analysis

In 1954, the term "probiotics" was coined by Ferdinand Vergin in his article. Although there are many clinical reports on the use of pro/synbiotics and other microbial preparations to prevent postoperative infections and related complications in patients with Colorectal cancer (CRC), their effectiveness remains divided. Therefore, we collected relevant high-quality randomized controlled trial (RCT) studies and conducted systematic review and meta-analysis. We electronically searched online databases (the PubMed, EMBASE, MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), Allied and Alternative Medieine (AMED), China National Knowledge Infrastructure (CNKI), Wanfang, and Weipu) for literature published until December 2020. These reports were rigorously screened, and the data extracted, assessed for risk of bias (ROB), and subjected to meta-analysis and subgroup analysis. Postoperative infections were the main criteria for outcomes. Nineteen high-quality articles were included, involving 1975 patients. Compared with the control group, the pro/synbiotics group had reduced total postoperative infections ((odds ratio)OR = 0.28, 95% (confidence interval)CI: 0.20; 0.39, p < 0.0001), which included surgical site infections (SSI) (OR = 0.43, 95% CI: 0.31; 0.58, p < 0.0001) and non-surgical site infections (non-SSI) (OR = 0.28 95% CI: 0.20; 0.39, p < 0.0001).What is more, in aspects of inflammatory factors, intestinal dysbiosis, non-infectious complications, and systemic symptoms, the treatment group was better than the control group. However, there were no differences in perineal infections (OR = 0.45, 95% CI: 0.13; 1.50, p = 0.1933), celiac infections (OR = 0.54, 95% CI: 0.11; 2.66, p = 0.4471), or systemic inflammatory response syndrome (SIRS) incidence (OR = 0.63, 95% CI: 0.31; 1.30, p = 0.2139), etc. There were no differences in intervention (probiotics or synbiotics), strain type (multistrain or non-multistrain probiotics), and intervention time (administration preoperatively or pre-and-postoperatively). Pro/synbiotics can effectively prevent postoperative infections and related complications in patients with CRC. The strain type and intervention time did not affect the treatment effects.

Physiological and Pathophysiological Consequences of a 25-Day Ultra-Endurance Exercise Challenge

Background: This case-report characterized the respiratory, cardiovascular, and nutritional/gastrointestinal (GI) responses of a trained individual to a novel ultra-endurance exercise challenge.

Case Presentation: A male athlete (age 45 years; V˙O₂max 54.0 mL⋅kg^-1⋅min^-1) summited 100 mountains on foot in 25 consecutive days (all elevations >600 m).

Measures: Laboratory measures of pulmonary function (spirometry, whole-body plethysmography, and single-breath rebreathe), respiratory muscle function (maximum static mouth-pressures), and cardiovascular structure and function (echocardiography, electrocardiography, large vessel ultrasound, and flow-mediated dilatation) were made at baseline and 48 h post-challenge. Dietary intake (four-day food diary), self-reported GI symptoms and plasma endotoxin concentrations were assessed at baseline, pre/post mid-point, pre/post end-point, and 48 h post-challenge.

Results: The challenge was completed in a total exercise time of 142 h (5.3 ± 2.8 h⋅d^-1), with a distance of 1141 km (42.3 ± 43.9 km⋅d^-1), and energy expenditure of 80460 kcal (2980 ± 1451 kcal⋅d^-1). Relative to baseline, there were post-challenge decreases in pulmonary capacities and expiratory flows (≤34%), maximum expiratory mouth-pressure (19%), and maximum voluntary ventilation (29%). Heart rate variability deteriorated, manifesting as a 48% decrease in the root mean square of successive differences and a 70% increase in the low-frequency/high-frequency ratio. Pre- to post-challenge endotoxin concentrations were elevated by 60%, with a maximum increase of 130% after a given stage, congruent with an increased frequency and severity of GI symptoms.

Conclusion: The challenge resulted in pulmonary and autonomic dysfunction, endotoxaemia, and GI distress. The findings extend our understanding of the limits of physiological function and may inform medical best-practice for personnel supporting ultra-endurance events.

Mammographic breast density and its association with urinary estrogens and the fecal microbiota in postmenopausal women

BACKGROUND

Breast density, as estimated by mammography, is a strong risk factor for breast cancer in pre- and postmenopausal women, but the determinants of breast density have not yet been established. The aim of this study was to assess if urinary estrogens or gut microbiota alterations are associated with mammographic density in postmenopausal women.

METHODS

Among 54 cancer-free, postmenopausal controls in the Breast and Colon Health study, we classified low- versus high-density women with Breast Imaging Reporting and Data System (BI-RADS, 5th edition) mammographic screening data, then assessed associations with urinary estrogens and estrogen metabolites (determined by liquid chromatography/tandem mass spectrometry), and fecal microbiota alpha and beta diversity (using Illumina sequencing of 16S rRNA amplicons).

RESULTS

Multiple logistic regression revealed no significant association between breast density and fecal microbiota metrics (PD_tree P-value = 0.82; un-weighted and weighted UniFrac P = 0.92 and 0.83, respectively, both by MiRKAT). In contrast, total urinary estrogens (and all 15 estrogens/estrogen metabolites) were strongly and inversely associated with breast density (P = 0.01) after adjustment for age and body mass index.

CONCLUSION

Mammographic density was not associated with the gut microbiota, but it was inversely associated with urinary estrogen levels.

IMPACT

The finding of an inverse association between urinary estrogens and breast density in cancer-free women adds to the growing breast cancer literature on understanding the relationship between endogenous estrogens and mammographic density.

Endurance exercise and gut microbiota: A review

BACKGROUND

The physiological and biochemical demands of intense exercise elicit both muscle-based and systemic responses. The main adaptations to endurance exercise include the correction of electrolyte imbalance, a decrease in glycogen storage and the increase of oxidative stress, intestinal permeability, muscle damage, and systemic inflammatory response. Adaptations to exercise might be influenced by the gut microbiota, which plays an important role in the production, storage, and expenditure of energy obtained from the diet as well as in inflammation, redox reactions, and hydration status.

METHODS

A systematic and comprehensive search of electronic databases, including MEDLINE, Scopus, ClinicalTrials.gov, ScienceDirect, Springer Link, and EMBASE was done. The search process was completed using the keywords: "endurance", "exercise", "immune response", "microbiota", "nutrition", and "probiotics".

RESULTS

Reviewed literature supports the hypothesis that intestinal microbiota might be able to provide a measureable, effective marker of an athlete's immune function and that microbial composition analysis might also be sensitive enough to detect exercise-induced stress and metabolic disorders. The review also supports the hypothesis that modifying the microbiota through the use of probiotics could be an important therapeutic tool to improve athletes' overall general health, performance, and energy availability while controlling inflammation and redox levels.

CONCLUSION

The present review provides a comprehensive overview of how gut microbiota may have a key role in controlling the oxidative stress and inflammatory responses as well as improving metabolism and energy expenditure during intense exercise.

Composition of gut microbiota in infants in China and global comparison

Symbiotic gut microbiota is essential for human health, and its compositional changes have been associated with various complex disorders. However, systematic investigation of the acquisition and development of gut microbial communities during early infancy are relatively rare, particularly for infants from non-Western countries. In this study, we characterize the colonization and development of infant microbiota in healthy Chinese infants and compare the pattern with those from other countries. The fecal microbiota of 2-month-old infants was considerably more diverse than that of neonates, as indicated by higher relative abundances of Veillonella, Clostridium, Bacteroides, Lactobacillus, Collinsella and Prevotella, and reduction of Escherichia and Enterococcus. The fecal microbiota of vaginally delivered infants (both neonates and 2-month-old) had significant enrichment of Bacteroides, Parabacteroides and Megamonas, whereas cesarean delivered infants had enrichment of Prevotella, Streptococcus and Trabulsiella. By global comparison, we identify three different enterotypes, referred as “P-type”, “A-type ”and “F-type” which were highly abundant in Proteobacteria, Actinobacteria and Firmicutes, respectively. The three enterotypes’ compositons vary geographically. All Chinese infants in our study belong to the P-type. These findings may provide novel insights into our understanding of the establishment of infant fecal bacterial communities.

Differences in microbial metabolites in urine headspace of subjects with Immune Thrombocytopenia (ITP) detected by volatile organic compound (VOC) analysis and metabolomics

ITP is an organ-specific autoimmune disorder characterised by a low platelet count whose cause is uncertain. A possible factor is food intolerance, although much of the information linking this with ITP is anecdotal. The role of food intolerance in ITP was studied by replacing a normal diet with an elemental diet (E028), but this did not increase platelet counts. Clear differences, however, were apparent between the volatile organic compounds (VOCs) in the urine headspace of patients with ITP and those present in healthy volunteers, which leads to speculation that abnormal metabolic activity of the intestinal microbiome may be a factor causing ITP. However, further work is needed to confirm this. There were also differences between the VOCs of patients on a normal diet and those on the elemental diet, and in this case, the VOCs involved are very likely to be of bacterial origin, as their production is affected by dietary manipulation. Many of these VOCs are known to be toxic.

Relationship between gastrointestinal micro-ecological imbalance and development of gastric cancer

The human body and microorganisms present in the body form a symbiotic system as the relationship between eukaryotes and prokaryotes. Therefore, it is not enough to study human diseases only in terms of human body. Recent studies have pointed out that microorganisms are involved in the occurrence of a large number of malignant tumors. According to a conservative estimate, at least 15% of cancer cases are associated with infectious agents. Gastric cancer is the second major cause of global cancer deaths. For a long period of time, researchers believe that Helicobacter pylori associated with chronic gastritis is the strongest risk factor for the occurrence of gastric cancer. However, with the progress of molecular biology research, it has been found that there is a close interaction between the large microbial flora and Helicobacter pylori in the gastrointestinal tract. The changes of microbial community composition have important effects on the formation, development and intervention of gastric cancer. This article will review the occurrence and development of gastrointestinal microorganism and gastric cancer.

Lactobacillus helveticus Lafti L10 supplementation reduces respiratory infection duration in a cohort of elite athletes: a randomized, double-blind, placebo-controlled trial

A randomized, double-blind, placebo-controlled study was conducted to evaluate if Lactobacillus helveticus Lafti L10 (Lallemand Health Solutions, Montreal, Que., Canada) supplementation during 14 weeks in winter can influence the duration, severity, and incidence of upper respiratory tract illness (URTI), as well as to monitor different immune parameters in the population of elite athletes. Before and after the treatment, cardiopulmonary testing and self-rated state of moods evaluation (by Profile of Mood States questionnaire) were performed and blood samples were collected. Thirty-nine elite athletes were randomized either to the placebo (n = 19) or the probiotic (n = 20) group. The probiotic group received L. helveticus Lafti L10, 2 × 10(10) Colony Forming Units. Lafti L10 significantly shortened the URTI episode duration (7.25 ± 2.90 vs. 10.64 ± 4.67 days, p = 0.047) and decreased the number of symptoms in the probiotic group (4.92 ± 1.96 vs. 6.91 ± 1.22, p = 0.035). Severity and incidence of URTI did not differ between the treatments. There were no significant changes in leukocyte subpopulation abundance, transforming growth factor-β serum levels, level of interleukin-10 secreted from peptidoglican stimulated peripheral blood mononuclear cells (PBMCs), interferon-γ level secreted from concanavalin A-stimulated PBMCs or viability/proliferation of PBMCs upon antigen stimulation. Group effect for CD4+/CD8+ ratio was significant (F[1,37] = 6.99, p = 0.020, η(2) = 0.350); this difference was not significant at baseline, but was evident after 14 weeks (p = 0.02). A significant interaction effect was noted for self-rated sense of vigor (F[1,37] = 11.76, p = 0.009, η(2) = 0.595). Self-rated sense of vigor increased in the probiotic group (18.5 ± 4.1 vs. 21.0 ± 2.6, p = 0.012). Probiotic strain Lafti L10 can be a beneficial nutritional supplement for the reduction of URTI length in elite athletes.

The gut microbiome, diet, and links to cardiometabolic and chronic disorders

Cardiometabolic diseases (CMDs) have been associated with changes in the composition of the gut microbiota, with links between the host environment and microbiota identified in preclinical models. High-throughput sequencing technology has facilitated in-depth studies of the gut microbiota, bacterial-derived metabolites, and their association with CMDs. Such strategies have shown that patients with CMDs frequently exhibit enrichment or depletion of certain bacterial groups in their resident microbiota compared to healthy individuals. Furthermore, the ability to transfer resident gut microbiota from mice or humans into germ-free mouse models, or between human patients, has enabled researchers to characterize the causative role of the gut microbiota in CMDs. These approaches have helped identify that dietary intake of choline, which is metabolized by the gut microbiota, is associated with cardiovascular outcomes in mice and humans. Trimethylamine N-oxide (TMAO) - a metabolite derived from the gut microbiota - is also associated with poor cardiovascular outcomes in patients with cardiovascular disease and is elevated in patients with chronic kidney disease (CKD). TMAO might represent a biomarker that links the environment and microbiota with CKD. This Review summarizes data suggesting a link between the gut microbiota and derived metabolites with food intake patterns, metabolic alterations, and chronic CMDs.

Cancer-promoting effects of microbial dysbiosis

Humans depend on our commensal bacteria for nutritive, immune-modulating, and metabolic contributions to maintenance of health. However, this commensal community exists in careful balance that, if disrupted, enters dysbiosis; this has been shown to contribute to the pathogenesis of colon, gastric, esophageal, pancreatic, laryngeal, breast, and gallbladder carcinomas. This development is closely tied to host inflammation, which causes and is aggravated by microbial dysbiosis and increases vulnerability to pathogens. Advances in sequencing technology have increased our ability to catalog microbial species associated with various cancer types across the body. However, defining microbial biomarkers as cancer predictors presents multiple challenges, and existing studies identifying cancer-associated bacteria have reported inconsistent outcomes. Combining metabolites and microbiome analyses can help elucidate interactions between gut microbiota, metabolism, and the host. Ultimately, understanding how gut dysbiosis impacts host response and inflammation will be critical to creating an accurate picture of the role of the microbiome in cancer.

Taxonomic Identification of Ruminal Epithelial Bacterial Diversity during Rumen Development in Goats

Understanding of the colonization process of epithelial bacteria attached to the rumen tissue during rumen development is very limited. Ruminal epithelial bacterial colonization is of great significance for the relationship between the microbiota and the host and can influence the early development and health of the host. MiSeq sequencing of 16S rRNA genes and quantitative real-time PCR (qPCR) were applied to characterize ruminal epithelial bacterial diversity during rumen development in this study. Seventeen goat kids were selected to reflect the no-rumination (0 and 7 days), transition (28 and 42 days), and rumination (70 days) phases of animal development. Alpha diversity indices (operational taxonomic unit [OTU] numbers, Chao estimate, and Shannon index) increased (P < 0.01) with age, and principal coordinate analysis (PCoA) revealed that the samples clustered together according to age group. Phylogenetic analysis revealed that Proteobacteria, Firmicutes, and Bacteroidetes were detected as the dominant phyla regardless of the age group, and the abundance of Proteobacteria declined quadratically with age (P < 0.001), while the abundances of Bacteroidetes (P = 0.088) and Firmicutes (P = 0.009) increased with age. At the genus level, Escherichia (80.79%) dominated at day zero, while Prevotella, Butyrivibrio, and Campylobacter surged (linearly; P < 0.01) in abundance at 42 and 70 days. qPCR showed that the total copy number of epithelial bacteria increased linearly (P = 0.013) with age. In addition, the abundances of the genera Butyrivibrio, Campylobacter, and Desulfobulbus were positively correlated with rumen weight, rumen papilla length, ruminal ammonia and total volatile fatty acid concentrations, and activities of carboxymethylcellulase (CMCase) and xylanase. Taking the data together, colonization by ruminal epithelial bacteria is age related (achieved at 2 months) and might participate in the anatomic and functional development of the rumen.

Pilot dietary intervention with heat-stabilized rice bran modulates stool microbiota and metabolites in healthy adults

Heat-stabilized rice bran (SRB) has been shown to regulate blood lipids and glucose, modulate gut mucosal immunity and inhibit colorectal cancer in animal and human studies. However, SRB’s effects on gut microbial composition and metabolism and the resulting implications for health remain largely unknown. A pilot, randomized-controlled trial was developed to investigate the effects of eating 30 g/day SRB on the stool microbiome and metabolome. Seven healthy participants consumed a study meal and snack daily for 28 days. The microbiome and metabolome were characterized using 454 pyrosequencing and gas chromatography-mass spectrometry (GC-MS) at baseline, two and four weeks post-intervention. Increases in eight operational taxonomic units (OTUs), including three from Bifidobacterium and Ruminococcus genera, were observed after two and four weeks of SRB consumption (p < 0.01). Branched chain fatty acids, secondary bile acids and eleven other putative microbial metabolites were significantly elevated in the SRB group after four weeks. The largest metabolite change was a rice bran component, indole-2-carboxylic acid, which showed a mean 12% increase with SRB consumption. These data support the feasibility of dietary SRB intervention in adults and support that SRB consumption can affect gut microbial metabolism. These findings warrant future investigations of larger cohorts evaluating SRB’s effects on intestinal health.

Adipokines and proinflammatory cytokines, the key mediators in the pathogenesis of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a condition in which excess fat accumulates in the liver of a patient with no history of alcohol abuse or other causes for secondary hepatic steatosis. The pathogenesis of NAFLD and nonalcoholic steatohepatitis (NASH) has not been fully elucidated. The “two-hit“ hypothesis is probably a too simplified model to elaborate complex pathogenetic events occurring in patients with NASH. It should be better regarded as a multiple step process, with accumulation of liver fat being the first step, followed by the development of necroinflammation and fibrosis. Adipose tissue, which has emerged as an endocrine organ with a key role in energy homeostasis, is responsive to both central and peripheral metabolic signals and is itself capable of secreting a number of proteins. These adipocyte-specific or enriched proteins, termed adipokines, have been shown to have a variety of local, peripheral, and central effects. In the current review, we explore the role of adipocytokines and proinflammatory cytokines in the pathogenesis of NAFLD. We particularly focus on adiponectin, leptin and ghrelin, with a brief mention of resistin, visfatin and retinol-binding protein 4 among adipokines, and tumor necrosis factor-α, interleukin (IL)-6, IL-1, and briefly IL-18 among proinflammatory cytokines. We update their role in NAFLD, as elucidated in experimental models and clinical practice.

Gastrointestinal cancers: influence of gut microbiota, probiotics and prebiotics

Cancers of the gastrointestinal (GI) tract continue to represent a major health problem, despite progress in therapy. Gut microbiota is a key element related to the genesis of GI cancers, countless papers addressing this burning issue across the world. We provide an updated knowledge of the involvement of gut microbiota in GI tumorigenesis, including its underlying mechanisms. We present also a comprehensive review of the evidence from animal and clinical studies using probiotics and/or prebiotics in the prevention and/or therapy of GI tumours, of GI cancer therapy-related toxicity and of post-operative complications. We summarize the anticarcinogenic mechanisms of these biotherapeutics from in vitro, animal and clinical interventions. More research is required to reveal the interactions of microflora with genetic, epigenetic and immunologic factors, diet and age, before any firm conclusion be drawn. Well-designed, randomized, double blind, placebo-controlled human studies using probiotics and/or prebiotics, with adequate follow-up are necessary in order to formulate directions for prevention and therapy.

Learned and unlearned concepts in periodontal diagnostics: a 50-year perspective

In the past 50 years, conceptual changes in the field of periodontal diagnostics have paralleled those associated with a better scientific understanding of the full spectrum of processes that affect periodontal health and disease. Fifty years ago, concepts regarding the diagnosis of periodontal diseases followed the classical pathology paradigm. It was believed that the two basic forms of destructive periodontal disease were chronic inflammatory periodontitis and 'periodontosis'- a degenerative condition. In the subsequent 25 years it was shown that periodontosis was an infection. By 1987, major new concepts regarding the diagnosis and pathogenesis of periodontitis included: (i) all cases of untreated gingivitis do not inevitably progress to periodontitis; (ii) progression of untreated periodontitis is often episodic; (iii) some sites with untreated periodontitis do not progress; (iv) a rather small population of specific bacteria ('periodontal pathogens') appear to be the main etiologic agents of chronic inflammatory periodontitis; and (v) tissue damage in periodontitis is primarily caused by inflammatory and immunologic host responses to infecting agents. The concepts that were in place by 1987 are still largely intact in 2012. However, in the decades to come, it is likely that new information on the human microbiome will change our current concepts concerning the prevention, diagnosis and treatment of periodontal diseases.

Bioengineered probiotics, a strategic approach to control enteric infections

Enteric infections account for high morbidity and mortality and are considered to be the fifth leading cause of death at all ages worldwide. Seventy percent of all enteric infections are foodborne. Thus significant efforts have been directed toward the detection, control and prevention of foodborne diseases. Many antimicrobials including antibiotics have been used for their control and prevention. However, probiotics offer a potential alternative intervention strategy owing to their general health beneficial properties and inhibitory effects against foodborne pathogens. Often, antimicrobial probiotic action is non-specific and non-discriminatory or may be ineffective. In such cases, bioengineered probiotics expressing foreign gene products to achieve specific function is highly desirable. In this review we summarize the strategic development of recombinant bioengineered probiotics to control enteric infections, and to examine how scientific advancements in the human microbiome and their immunomodulatory effects help develop such novel and safe bioengineered probiotics.

Timely approaches to identify probiotic species of the genus Lactobacillus

Over the past decades the use of probiotics in food has increased largely due to the manufacturer’s interest in placing “healthy” food on the market based on the consumer’s ambitions to live healthy. Due to this trend, health benefits of products containing probiotic strains such as lactobacilli are promoted and probiotic strains have been established in many different products with their numbers increasing steadily. Probiotics are used as starter cultures in dairy products such as cheese or yoghurts and in addition they are also utilized in non-dairy products such as fermented vegetables, fermented meat and pharmaceuticals, thereby, covering a large variety of products.

To assure quality management, several pheno-, physico- and genotyping methods have been established to unambiguously identify probiotic lactobacilli. These methods are often specific enough to identify the probiotic strains at genus and species levels. However, the probiotic ability is often strain dependent and it is impossible to distinguish strains by basic microbiological methods.

Therefore, this review aims to critically summarize and evaluate conventional identification methods for the genus Lactobacillus, complemented by techniques that are currently being developed.

Is type 1 diabetes a food-induced disease?

The incidence of type 1 diabetes among children has almost doubled during the last decades in Sweden. Type 1 diabetes is considered as an autoimmune disease with unknown aetiology. Here we propose that the immune reaction may be initiated by food-derived mechanisms. The incidence of diabetes parallels an increased consumption of pasta, white bread, meat, cheese, low-fat milk, exotic fruits, soda, and snacks. Simultaneously, the consumption of potatoes, butter, high-fat milk, and domestic fruit has decreased. Three categories of food related reaction mechanisms are discussed against the following items (1) proteins from wheat, meat, and milk, (2) fat from processed food, and (3) exotic fruits. The current food consumption is suggested to initiate a pro-inflammatory reaction in the intestine and thereby reduce the intestinal barrier function. This may influence tolerance development and thus pave the way for an autoimmune attack on pancreatic beta cells.

Ageing and gut microbes: perspectives for health maintenance and longevity

The ageing process affects the human gut microbiota phylogenetic composition and its interaction with the immune system. Age-related gut microbiota modifications are associated with immunosenescence and inflamm-ageing in a sort of self-sustaining loop, which allows the placement of gut microbiota unbalances among both the causes and the effects of the inflamm-ageing process. Even if, up to now, the link between gut microbiota and the ageing process is only partially understood, the gut ecosystem shows the potential to become a promising target for strategies able to contribute to the health status of older people. In this context, the consumption of pro/prebiotics may be useful in both prevention and treatment of age-related pathophysiological conditions, such as recovery and promotion of immune functions, i.e. adjuvant effect for influenza vaccine, and prevention and/or alleviation of common "winter diseases", as well as constipation and Clostridium difficile-associated diarrhoea. Moreover, being involved in different mechanisms which concur in counteracting inflammation, such as down-regulation of inflammation-associated genes and improvement of colonic mucosa conditions, probiotics have the potentiality to be involved in the promotion of longevity.

Probiotics, prebiotics, synbiotics: is there enough evidence to support their use in colorectal cancer surgery?

BACKGROUND/AIMS

Pro-/pre-/synbiotics supplementation seems to provide beneficial effects in various aspects of abdominal pathology. Skepticism exists with respect to their effects on colorectal cancer (CRC) patients. This review presents the potential clinical applications of pro-/pre-/synbiotics in CRC surgery.

METHODS

A literature search of electronic databases was conducted and all studies published on 'probiotics', 'prebiotics' and 'synbiotics' were collected. Among them, the ones referring to CRC and which had any clinical relevance offering information on perioperative parameters were used.

RESULTS

Incorporation of pre-/pro-/synbiotic formulations in the preoperative mechanical bowel preparation cannot be supported by the current evidence. Limited clinical studies may be promising in supporting their potentially protective role against postoperative infectious complications. Encouraging are the results on their protective role against adjuvant (chemo)radiation-induced diarrhea. Such supplementation may also hold promise to improve postcolectomy gastrointestinal related quality of life.

CONCLUSIONS

Despite the positive results and plethora of agents, bacterial combinations and concentrations, the inconsistency in administration, the inhomogeneity of comparison groups and lack of stringent clinical endpoints remain obstacles in the effort to establish a definitive clinical strategy at this time. Further work is warranted to gain a keen understanding of their clinical value in CRC patients.

Dietary Factors: Major Regulators of the Gut's Microbiota

Dietary factors and the associated lifestyle play a major role in the pathophysiology of many diseases. Several diets, especially a Western lifestyle with a high consumption of meat and carbohydrates and a low consumption of vegetables, have been linked to common diseases, such as metabolic syndrome, atherosclerosis, inflammatory bowel diseases, and colon cancer. The gastrointestinal tract harbors a complex and yet mainly molecularly defined microbiota, which contains an enormous number of different species. Recent advances in sequencing technologies have allowed the characterization of the human microbiome and opened the possibility to study the effect of "environmental" factors on this microbiome. The most important environmental factor is probably "what we eat," and the initial studies have revealed fascinating results on the interaction of nutrients with our microbiota. Whereas short-term changes in dietary patterns may not have major influences, long-term diets can affect the microbiota in a substantial manner. This issue may potentially have major relevance for human gastrointestinal health and disease because our microbiota has features to regulate many immune and metabolic functions. Increasing our knowledge on the interaction between nutrients and microbiota may have tremendous consequences and result in a better understanding of diseases, even beyond the gastrointestinal tract, and finally lead to better preventive and therapeutic strategies.

Rotavirus vaccination in developing countries

Although two oral rotavirus vaccines are licensed in many countries, multiple factors may affect decision-making regarding introduction into national immunization programs in developing countries. Financial and logistic challenges to introduction of rotavirus vaccines in countries with limited infrastructure and resources are accompanied by a perceived lack of need and evidence from recent vaccine trials, which demonstrated significantly lower efficacy in high burden countries. Nonetheless, even at a low efficacy, the use of existing vaccines in developing countries is predicted to alleviate considerable rotavirus disease burden and mortality. Potential alternate strategies for improving response to existing vaccines or the development of improved vaccines need to be considered to ensure that the remaining burden of mortality and morbidity can be addressed in the future.

Gut-central nervous system axis is a target for nutritional therapies

Historically, in the 1950s, the chemist Linus Pauling established a relationship between decreased longevity and obesity. At this time, with the advent of studies involving the mechanisms that modulate appetite control, some researchers observed that the hypothalamus is the "appetite centre" and that peripheral tissues have important roles in the modulation of gut inflammatory processes and levels of hormones that control food intake. Likewise, the advances of physiological and molecular mechanisms for patients with obesity, type 2 diabetes mellitus, inflammatory bowel diseases, bariatric surgery and anorexia-associated diseases has been greatly appreciated by nutritionists. Therefore, this review highlights the relationship between the gut-central nervous system axis and targets for nutritional therapies.

Modern approaches in probiotics research to control foodborne pathogens

Foodborne illness is a serious public health concern. There are over 200 known microbial, chemical, and physical agents that are known to cause foodborne illness. Efforts are made for improved detection, control and prevention of foodborne pathogen in food, and pathogen associated diseases in the host. Several commonly used approaches to control foodborne pathogens include antibiotics, natural antimicrobials, bacteriophages, bacteriocins, ionizing radiations, and heat. In addition, probiotics offer a potential intervention strategy for the prevention and control of foodborne infections. This review focuses on the use of probiotics and bioengineered probiotics to control foodborne pathogens, their antimicrobial actions, and their delivery strategies. Although probiotics have been demonstrated to be effective in antagonizing foodborne pathogens, challenges exist in the characterization and elucidation of underlying molecular mechanisms of action and in the development of potential delivery strategies that could maintain the viability and functionality of the probiotic in the target organ.