Breath Methane Levels Are Increased Among Patients with Diverticulosis

The relationship between small intestinal bacterial overgrowth and constipation in children - a comprehensive review

Small intestinal bacterial overgrowth (SIBO) is characterized by an increase in the bacterial population of the small intestine due to an imbalance between the amount of bacteria and the intestinal barrier. Pediatric SIBO presents with a wide spectrum of symptoms, ranging from mild gastrointestinal complaints to malabsorption or malnutrition. Breath tests are commonly used as noninvasive diagnostic tools for SIBO, but a standardized methodology is currently unavailable. Intestinal flora produces methane which slows intestinal transit and increases the contractile activity of small intestine. Emerging literature suggests a correlation between overgrowth of methanogenic bacteria in the intestines and constipation. Treatment of SIBO involves administration of antibacterial therapy in addition to management of underlying conditions and optimal dietary adjustments. However, research on antibiotic treatment for pediatric patients with constipation and SIBO is limited and has yielded conflicting results. In the current review, we summarize the state-of-the-art of the field and discuss previous treatment attempts and currently used regimens for SIBO patients with constipation, with a focus on pediatric populations.

The Archaea domain: Exploring historical and contemporary perspectives with in silico primer coverage analysis for future research in Dentistry

OBJECTIVE

The complete picture of how the human microbiome interacts with its host is still largely unknown, particularly concerning microorganisms beyond bacteria. Although existing in very low abundance and not directly linked to causing diseases, archaea have been detected in various sites of the human body, including the gastrointestinal tract, oral cavity, skin, eyes, respiratory and urinary systems. But what exactly are these microorganisms? In the early 1990 s, archaea were classified as a distinct domain of life, sharing a more recent common ancestor with eukaryotes than with bacteria. While archaea's presence and potential significance in Dentistry remain under-recognized, there are concerns that they may contribute to oral dysbiosis. However, detecting archaea in oral samples presents challenges, including difficulties in culturing, the selection of DNA extraction methods, primer design, bioinformatic analysis, and databases.

DESIGN

This is a comprehensive review on the oral archaeome, presenting an in-depth in silico analysis of various primers commonly used for detecting archaea in human body sites.

RESULTS

Among several primer pairs used for detecting archaea in human samples across the literature, only one specifically designed for detecting methanogenic archaea in stool samples, exhibited exceptional coverage levels for the domain and various archaea phyla.

CONCLUSIONS

Our in silico analysis underscores the need for designing new primers targeting not only methanogenic archaea but also nanoarchaeal and thaumarchaeota groups to gain a comprehensive understanding of the archaeal oral community. By doing so, researchers can pave the way for further advancements in the field of oral archaeome research.

Modification of baseline status to improve breath tests performance

Breath tests used to evaluate carbohydrates malabsorption require baseline H2 and CH4 levels as low as possible. Test cancellation is recommended when exceeding certain cut-offs (H2 ≥ 20 ppm and CH4 ≥ 10 ppm). Although following preparation protocols, many patients have baseline levels above those cut-offs. We investigated if light walking can reduce baseline H2 and CH4 levels. We retrospectively analyzed baseline H2 and CH4 levels from 1552 breath tests. Baseline levels (B1), especially in H2, were lower when obtained at later hours of the day. In those with baseline levels above cut-off, re-sampling (B2) after light walking for one hour, decreased H2 levels 8 ppm (Q1-Q3: 1-18 ppm), and 2 ppm (Q1-Q3: 0-3 ppm) for CH4. Consequently, 40% of tests with elevated B1 levels, presented B2 levels below mentioned cut-offs. Ten percent of tests considered negative when using B1 for calculations, turned positive when using B2 instead. All positive tests when using B1 values, remained elevated when using B2. Re-sampling after light walking for one hour could allow test performance in those with previous elevated baseline levels, avoiding diagnosis delays. Using the second sample for delta calculations identifies positive patients for malabsorption that would have been considered negative.

Bacteria and Methanogens in the Human Microbiome: a Review of Syntrophic Interactions

Methanogens are microorganisms belonging to the Archaea domain and represent the primary source of biotic methane. Methanogens encode a series of enzymes which can convert secondary substrates into methane following three major methanogenesis pathways. Initially recognized as environmental microorganisms, methanogens have more recently been acknowledged as host-associated microorganisms after their detection and initial isolation in ruminants in the 1950s. Methanogens have also been co-detected with bacteria in various pathological situations, bringing their role as pathogens into question. Here, we review reported associations between methanogens and bacteria in physiological and pathological situations in order to understand the metabolic interactions explaining these associations. To do so, we describe the origin of the metabolites used for methanogenesis and highlight the central role of methanogens in the syntrophic process during carbon cycling. We then focus on the metabolic abilities of co-detected bacterial species described in the literature and infer from their genomes the probable mechanisms of their association with methanogens. The syntrophic interactions between bacteria and methanogens are paramount to gut homeostasis. Therefore, any dysbiosis affecting methanogens might impact human health. Thus, the monitoring of methanogens may be used as a bio-indicator of dysbiosis. Moreover, new therapeutic approaches can be developed based on their administration as probiotics. We thus insist on the importance of investigating methanogens in clinical microbiology.

Detection of methanogens in peri-appendicular abscesses: Report of four cases

The aetiology of appendicular abscess is predominantly microbial with aerobic and anaerobic bacteria from gut flora. In this study, by using specific laboratory tools, we co-detected Methanobrevibacter oralis and Methanobrevibacter smithii among a mixture of enterobacteria including Escherichia coli, Enterococcus faecium and Enterococcus avium in four unrelated cases of postoperative appendiceal abscesses. These unprecedented observations raise a question on the role of methanogens in peri-appendicular abscesses, supporting antibiotics as an alternative therapeutic option for appendicitis, including antibiotics active against methanogens such as metronidazole or fusidic acid.

Magnetic Resonance Imaging of Diverticular Disease and its Association with Adipose Tissue Compartments and Constitutional Risk Factors in Subjects from a Western General Population

PURPOSE

 To determine the association of asymptomatic diverticular disease as assessed by magnetic resonance imaging (MRI) with adipose tissue compartments, hepatic steatosis and constitutional risk factors within a cohort drawn from a Western general population.

MATERIALS AND METHODS

 Asymptomatic subjects enrolled in a prospective case-control study underwent a 3 Tesla MRI scan, including an isotropic VIBE-Dixon sequence of the entire trunk. The presence and extent of diverticular disease were categorized according to the number of diverticula in each colonic segment in a blinded fashion. The amount of visceral, subcutaneous, and total adipose tissue (VAT, SAT, and TAT) was quantified by MRI. Additionally, the degree of hepatic steatosis, indicated as hepatic proton density fat fraction (hepatic PDFF) was determined using a multi-echo T1w sequence. Constitutional cardiometabolic risk factors were obtained and univariate and multivariate associations were calculated.

RESULTS

 A total of 371 subjects were included in the analysis (58.2 % male, 56.2 ± 9.2 years). Based on MRI, 154 participants (41.5 %) had diverticular disease with 62 cases (17 %) being advanced diverticular disease. Subjects with advanced diverticular disease had a significantly higher body mass index (BMI) (BMI: 29.9 ± 5.1 vs. 27.5 ± 4.6, p < 0.001; respectively). Furthermore, all adipose tissue compartments were increased in subjects with advanced diverticular disease (e. g. VAT: 6.0 ± 2.8 vs. 4.2 ± 2.6 and SAT: 9.2 ± 3.6 vs. 7.8 ± 3.6, all p < 0.001, respectively). Similarly, subjects with advanced diverticular disease had significantly higher hepatic PDFF (4.9 [2.7, 11.4] vs. 6.1 [5.5, 14.6], p = 0.002).

CONCLUSION

 Advanced diverticular disease is associated with an increased volume of adipose tissue compartments and BMI, which may suggest a metabolic role in disease development.

KEY POINTS

· Diverticular disease is associated with constitutional risk factors such as BMI.. · Excess of adipose tissue compartments and hepatic steatosis are associated with the prevalence of diverticular disease.. · Our results suggest a shared pathological pathway of cardiometabolic alterations and the prevalence of diverticular disease.. · MRI is feasible for the assessment of adipose tissue compartments, hepatic steatosis, and diverticular disease and allows identification of patients who are at risk but in an asymptomatic disease state..

CITATION FORMAT

· Storz C, Rospleszcz S, Askani E et al. Magnetic Resonance Imaging of Diverticular Disease and its Association with Adipose Tissue Compartments and Constitutional Risk Factors in Subjects from a Western General Population. Fortschr Röntgenstr 2021; 193: 33 - 41.

Digestive tract methanodrome: Physiological roles of human microbiota-associated methanogens

Methanogens are the archaea most commonly found in humans, in particular in the digestive tract and are an integral part of the digestive microbiota. They are present in humans from the earliest moments of life and represent the only known source of methane production to date. They are notably detected in humans by microscopy, fluorescent in situ hybridization, molecular biology including PCR-sequencing, metagenomics, matrix-assisted laser desorption ionization time-of-flight mass spectrometry and culture. Methanogens present in the human digestive tract play major roles, in particular the use of hydrogen from the fermentation products of bacteria, thus promoting digestion. They are also involved in the transformation of heavy metals and in the use of trimethylamine produced by intestinal bacteria, thus preventing major health problems, in particular cardiovascular diseases. Several pieces of evidence suggest their close physical contacts with bacteria support symbiotic metabolism. Their imbalance during dysbiosis is associated with many pathologies in humans, particularly digestive tract diseases such as Crohn's disease, ulcerative colitis, diverticulosis, inflammatory bowel disease, irritable bowel syndrome, colonic polyposis, and colorectal cancer. There is a huge deficit of knowledge and partially contradictory information concerning human methanogens, so much remains to be done to fully understand their physiological role in humans. It is necessary to develop new methods for the identification and culture of methanogens from clinical samples. This will permit to isolate new methanogens species as well as their phenotypic characterization, to explore their genome by sequencing and to study the population dynamics of methanogens by specifying in particular their exact role within the complex flora associated with the mucous microbiota of human.

Lactose Intolerance: What Your Breath Can Tell You

Lactose intolerance has seen recognized as a clinical syndrome characterized by pain, abdominal distention, flatulence, and diarrhea after the consumption of lactose. Lactose is a common disaccharide found in dairy that requires lactase-phlorizin hydrolase (LPH) to break down into glucose and galactose. A deficiency in this enzyme results in flora bacteria further along in the gastrointestinal tract (GI) tract to metabolize the excess lactose to numerous gases, including H₂. Recent studies show that the risk of symptoms after lactose ingestion depends on the dose of lactose, LPH expression, intestinal flora, and sensitivity of the gastrointestinal tract. Currently, there are several diagnostic tests that investigate the biological mechanism of lactose intolerance such as blood, biopsy, genetic, and breath tests. Due to its relatively low cost, availability, and non-invasiveness, the hydrogen breath test (HBT) has become a popular technology to aid in the diagnosis of many gastroenterological diseases, specifically lactose intolerance. Additionally, while administering the HBT there seems to be a lack of uniform criteria amongst the various studies, with many using their own guidelines, which may in turn cause inconsistency with the analysis of the results. With ever improving nanotechnology, novel approaches to expedite and lower the costs of the HBT has become an area of research with significant advancements.

Methanogenic Archaea: Emerging Partners in the Field of Allergic Diseases

Archaea, which form one of four domains of life alongside Eukarya, Bacteria, and giant viruses, have long been neglected as components of the human microbiota and potential opportunistic infectious pathogens. In this review, we focus on methanogenic Archaea, which rely on hydrogen for their metabolism and growth. On one hand, methanogenic Archaea in the gut are functional associates of the fermentative digestion of dietary fibers, favoring the production of beneficial short-chain fatty acids and likely contributing to the weaning reaction during the neonatal window of opportunity. On the other hand, methanogenic Archaea trigger the activation of innate and adaptive responses and the generation of specific T and B cells in animals and humans. In mouse models, lung hypersensitivity reactions can be induced by inhaled methanogenic Archaea mimicking human professional exposure to organic dust. Changes in methanogenic Archaea of the microbiota are detected in an array of dysimmune conditions comprising inflammatory bowel disease, obesity, malnutrition, anorexia, colorectal cancer, and diverticulosis. At the subcellular level, methanogenic Archaea are activators of the TLR8-dependent NLRP3 inflammasome, modulate the release of antimicrobial peptides and drive the production of proinflammatory, Th-1, Th-2, and Th-17 cytokines. Our objective was to introduce the most recent and major pieces of evidence supporting the involvement of Archaea in the balance between health and dysimmune diseases, with a particular focus on atopic and allergic conditions.

The human archaeome: methodological pitfalls and knowledge gaps

Forty years ago, archaea were described as a separate domain of life, distinct from bacteria and eukarya. Although it is known for quite a long time that methanogenic archaea are substantial components of the human gastrointestinal tract (GIT) and the oral cavity, the knowledge on the human archaeome is very limited. Various methodological problems contribute to the invisibility of the human archaeome, resulting in severe knowledge gaps and contradictory information. Similar to the bacteriome, the archaeal biogeography was found to be site-specific, forming (i) the thaumarchaeal skin landscape, (ii) the (methano)euryarchaeal GIT landscape, (iii) a mixed skin/GIT landscape in nose, and (iv) a woesearchaeal lung landscape, including numerous unknown archaeal clades. Compared with so-called universal microbiome approaches, archaea-specific protocols reveal a wide diversity and high quantity of archaeal signatures in various human tissues, with up to 1 : 1 ratios of bacteria and archaea in appendix and nose samples. The archaeome interacts closely with the bacteriome and the human body cells, whereas the roles of the human-associated archaea with respect to human health are only sparsely described. Methanogenic archaea and methane production were correlated with many health issues, including constipation, periodontitis and multiple sclerosis. However, one of the most burning questions - do archaeal pathogens exist? - still remains obscure to date.

Increasing Diverticulosis in an Aging Population: A Colonoscopy-Based Study of 5-Year Trends in 26 463 Patients in Northern China

Background

Because such data are scarce in northern China, the purpose of this study was to determine trends in diverticulosis over the past 5 years.

Material/Methods

A total of 26 463 patients (27 558 examinations, including 1095 repeated colonoscopies) performed between January 2011 and December 2015 were reviewed respectively. The distributions of diverticulosis were recorded, which were classified as right-sided, left-sided, and bilateral type. The trends in diverticulosis were analyzed in terms of aging and yearly increase. Additionally, associations of the occurrence of diverticulosis with age (≤39, 40–59, and ≥60 years) and sex were determined using a logistic regression model.

Results

We identified 1045 patients with colonic diverticulosis, with an overall prevalence of 3.8% (1045/27 558). A preponderance of right-sided diverticulosis was demonstrated, accounting for 72.9% (693/951) of included subjects. The proportion of colonic diverticulosis increased significantly (P<0.001 for trend), from 2.78% (112/4028) in 2011 to 4.98% (309/6208) in 2015. The proportion of patients of all age groups with diverticulosis increased significantly (P<0.001 for trend) in correlation with yearly increase. There was a greater proportion of diverticulosis, regardless of the distribution, in patients aged ≥60 than in younger age groups (P<0.001 for trend). Multivariate analysis showed older age and male sex (P<0.001) were independent risk factor for diverticulosis.

Conclusions

Colonic diverticulosis has been increasing in northern China, where rapid aging is ongoing.

Obesity and the Risk of Colonic Diverticulosis: A Meta-analysis

BACKGROUND

The possible relationship between obesity and the risk of colonic diverticulosis has been suggested by recent epidemiologic studies, although the results were inconsistent.

OBJECTIVE

This systematic review and meta-analysis was conducted to summarize all of the available data.

DATA SOURCES

A comprehensive literature review was conducted using the MEDLINE and EMBASE databases through January 2017.

STUDY SELECTION

Studies that compared the risk of colonic diverticulosis among subjects with obesity versus those without obesity were included.

MAIN OUTCOME MEASURES

Effect estimates from each study were extracted and combined together using a random-effect, generic inverse variance method.

RESULTS

Of 2989 potentially eligible articles, 10 studies (9 cross-sectional studies and 1 prospective cohort study) with 53,520 participants met the eligibility criteria and were included in the meta-analysis. The risk of colonic diverticulosis in obese subjects was significantly higher than in those without obesity, with a pooled OR of 1.41 (95% CI, 1.20-1.65). The statistical heterogeneity was high, with an I of 75%.

LIMITATIONS

High statistical heterogeneity and publication bias in favor of positive studies may have been present in this meta-analysis.

CONCLUSIONS

A significant association between colonic diverticulosis and obesity was shown in this study. However, additional studies are still required to determine the causality. See Video Abstract at http://links.lww.com/DCR/A500.

Sex differences in risk factors of uncomplicated colonic diverticulosis in a metropolitan area from Northern China

As the world’s most populated and rapidly aging country, there is limited information on sex-related differences in factors regarding uncomplicated colonic diverticulosis in China. We aimed to investigate sex differences in individual risk factor in a northern metropolis. Patients with colonic diverticulosis who underwent indicated colonoscopy were queried with respect to medical history and demographic features. Demographic information, life style factors and co-morbidities were retrieved from a prospective dataset. Multiple regression analyses were performed to determine precipitating factors of diverticula. Of 4,386 enrolled patients, colonic diverticulosis were detected in 218 cases (4.97%). Multiple logistic regression analysis implicated increasing age (OR = 1.05, 95%CI 1.03–1.06, P < 0.001), red meat ≥100 g/d (OR = 2.53, 95%CI 1.72–3.70, P < 0.001), smoking (OR = 2.14, 95%CI 1.05–4.33, P = 0.035), rheumatologic diseases (OR = 3.38, 95%CI 1.09–10.5, P = 0.035) and NSAIDs (OR = 2.11, 95%CI 1.12–3.97, P = 0.020) were significantly associated with diverticulosis in men, whilst advancing age (OR = 1.03, 95%CI 1.01–1.05, P = 0.013), BMI (OR = 1.12, 95%CI 1.04–1.19, P = 0.001), smoking (OR = 10.2, 95%CI 2.81–37.4, P < 0.001), rheumatologic diseases (OR = 8.04, 95%CI 3.05–21.2, P < 0.001), hypertension (OR = 1.76, 95%CI 1.01–3.06, P = 0.047), colonic polyps (OR = 3.12, 95%CI 1.82–5.36, P < 0.001) and antihypertensive medications (OR = 2.99, 95%CI 1.66–5.39, P < 0.001) in women. In conclusion, it is pivotal to take account of differentially sex-related factors in regard to the development of uncomplicated colonic diverticulosis.

Logical hypothesis: Low FODMAP diet to prevent diverticulitis

Despite little evidence for the therapeutic benefits of a high-fiber diet for diverticulitis, it is commonly recommended as part of the clinical management. The ongoing uncertainty of the cause(s) of diverticulitis confounds attempts to determine the validity of this therapy. However, the features of a high-fiber diet represent a logical contradiction for colon diverticulitis. Considering that Bernoulli’s principle, by which enlarged diameter of the lumen leads to increased pressure and decreased fluid velocity, might contribute to development of the diverticulum. Thus, theoretically, prevention of high pressure in the colon would be important and adoption of a low FODMAP diet (consisting of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) may help prevent recurrence of diverticulitis.