Larger amounts of nitrite and nitrate-reducing bacteria in megaesophagus of Chagas' disease than in controls

From nitrate to NO: potential effects of nitrate-reducing bacteria on systemic health and disease

Current research has described improving multisystem disease and organ function through dietary nitrate (DN) supplementation. They have provided some evidence that these floras with nitrate (NO3-) reductase are mediators of the underlying mechanism. Symbiotic bacteria with nitrate reductase activity (NRA) are found in the human digestive tract, including the mouth, esophagus and gastrointestinal tract (GT). Nitrate in food can be converted to nitrite under the tongue or in the stomach by these symbiotic bacteria. Then, nitrite is transformed to nitric oxide (NO) by non-enzymatic synthesis. NO is currently recognized as a potent bioactive agent with biological activities, such as vasodilation, regulation of cardiomyocyte function, neurotransmission, suppression of platelet agglutination, and prevention of vascular smooth muscle cell proliferation. NO also can be produced through the conventional L-arginine-NO synthase (L-NOS) pathway, whereas endogenous NO production by L-arginine is inhibited under hypoxia-ischemia or disease conditions. In contrast, exogenous NO3-/NO2-/NO activity is enhanced and becomes a practical supplemental pathway for NO in the body, playing an essential role in various physiological activities. Moreover, many diseases (such as metabolic or geriatric diseases) are primarily associated with disorders of endogenous NO synthesis, and NO generation from the exogenous NO3-/NO2-/NO route can partially alleviate the disease progression. The imbalance of NO in the body may be one of the potential mechanisms of disease development. Therefore, the impact of these floras with nitrate reductase on host systemic health through exogenous NO3-/NO2-/NO pathway production of NO or direct regulation of floras ecological balance is essential (e.g., regulation of body homeostasis, amelioration of diseases, etc.). This review summarizes the bacteria with nitrate reductase in humans, emphasizing the relationship between the metabolic processes of this microflora and host systemic health and disease. The potential effects of nitrate reduction bacteria on human health and disease were also highlighted in disease models from different human systems, including digestive, cardiovascular, endocrine, nervous, respiratory, and urinary systems, providing innovative ideas for future disease diagnosis and treatment based on nitrate reduction bacteria.

The Mechanisms for the Association of Cancer and Esophageal Dysmotility Disorders

BACKGROUND

Achalasia and other esophageal dysmotility disorders mimicking achalasia can be associated with cancer. This study aimed to review the main mechanisms for which cancer may develop in esophageal dysmotility disorder patients.

METHODS

A narrative review was performed.

RESULTS

The mechanism for developing squamous cell carcinoma and adenocarcinoma are discussed. Besides, achalasia-like syndromes related to familial KIT-gene mutation and pseudoachalasia are discussed.

CONCLUSIONS

Knowing the main mechanism for which achalasia can be related to cancer is essential for clinicians to conduct the proper investigation, surveillance, and treatment.

Investigation of oral, gastric, and duodenal microbiota in patients with upper gastrointestinal symptoms

Disease-associated alterations of the intestinal microbiota composition, known as dysbiosis, have been well described in several functional gastrointestinal (GI) disorders. Several studies have described alterations in the gastric microbiota in functional dyspepsia, but very few have looked at the duodenum.Here, we explored the upper GI tract microbiota of inpatients with upper GI dyspeptic symptoms, and compared them to achalasia controls, as there is no indication for an esophagogastroduodenoscopy in healthy individuals.We found differences in the microbiota composition at the three sites evaluated (ie, saliva, stomach and duodenum). Changes observed in patients with dyspepsia included an increase in Veillonella in saliva, an oral shift in the composition of the gastric microbiota, and to some degree in the duodenum as well, where an important abundance of anaerobes was observed. Metabolic function prediction identified greater anaerobic metabolism in the stomach microbial community of patients with dyspepsia. Proton pump inhibitor use was not associated with any particular genus. Co-abundance analysis revealed Rothia as the main hub in the duodenum, a genus that significantly correlated with the relative abundance of Clostridium, Haemophilus, and ActinobacillusWe conclude that patients with upper GI symptoms consistent with dyspepsia have alterations in the microbiota of saliva, the stomach, and duodenum, which could contribute to symptoms of functional GI disorders.

Intestinal microbiota - A modulator of the Trypanosoma cruzi-vector-host triad

Chagas disease affects millions of people, and it is a major cause of death in Latin America. Prevention and development of an effective treatment for this infection can be favored by a more thorough understanding of T. cruzi interaction with the microbiome of vectors and hosts. Next-generation sequencing technology vastly broadened the knowledge about intestinal bacteria composition, showing that microbiota within each host (triatomines and mammals) is composed by high diversity of species, although few dominant phyla. This fact may represent an ecological balance that was acquired during the evolutionary process of the microbiome-host complex, and that serves to perpetuate this system. In this context, commensal microbiota is also essential to protect hosts, conferring them resistance to pathogens colonization. However, in some situations, the microbiota is not able to prevent infection but only modulate it. Here we will review the role of the microbiota on the parasite-vector-host triad with a focus on the kinetoplastida of medical importance Trypanosoma cruzi. Novel strategies to control Chagas disease based on intestinal microbiome will also be discussed.

The Esophageal Microbiome in Health and Disease

PURPOSE OF REVIEW

Investigation of the esophageal microbiome is a relatively new field. This review will outline data characterizing the esophageal microbiome in both health and disease states, including gastroesophageal reflux disease (GERD), Barrett's esophagus, esophageal cancer, eosinophilic esophagitis, and motility disorders.

RECENT FINDINGS

While the esophagus was previously considered devoid of a significant bacterial population, development of culture-independent techniques, specifically 16S rRNA gene sequencing, as well as novel, minimally invasive microbial sampling modalities, has facilitated characterization of the esophageal microbiome in both health and several disease states. Although limited, there is evidence that the esophagus contains a diverse microbial population, with Gram-positive bacteria, specifically Streptococcus, dominating in health, while Gram-negative bacteria prevail in reflux disorders including GERD and Barrett's esophagus. The microbiome is altered with other esophageal disorders as well, including eosinophilic esophagitis and esophageal motility disorders, though these changes have been less well characterized. Characterization of the gut microbiome has advanced significantly; however, further investigation is essential. Understanding changes in the esophageal microbiome could affect our understanding of the natural history of diseases of the esophagus and present potential therapeutic approaches.

High Prevalence of Barrett's Esophagus and Esophageal Squamous Cell Carcinoma After Repair of Esophageal Atresia

BACKGROUND & AIMS

Esophageal atresia is rare, but improved surgical and intensive care techniques have increased rates of survival in children, so there are now many adults with this disorder. Many patients with esophageal atresia develop gastroesophageal reflux (GER), raising concerns about increased risk of Barrett's esophagus (BE; prevalence of 1.3%-1.6% in general population) and esophageal carcinoma. We assessed the prevalence of BE and esophageal carcinoma in this population.

METHODS

We performed a prospective study of 289 patients with esophageal atresia at the Department of Gastroenterology and Hepatology at Erasmus MC University Medical Center in The Netherlands, from May 2012 through March 2017. A total of 151 (median age, 25.4 y; age range, 16.8-68.6 y) underwent upper endoscopies as part of a surveillance program for (pre)malignant esophageal lesions. Biopsies were collected and analyzed by histology. We collected data on patients' use of medications, tobacco, and alcohol; gastrointestinal symptoms; ability to swallow; complaints of GER; and type of atresia and surgeries. Prevalence of esophageal squamous cell carcinoma (ESCC) was determined using data from The Netherlands Cancer Registry. The number of persons alive on January 1, 2016, in the esophageal atresia cohort and in the general Dutch population were used to calculate the 10-year prevalence of ESCC per 100,000 persons in both populations.

RESULTS

Forty-seven percent of patients with esophageal atresia had a history of GER and 20.5% had undergone fundoplication surgery. Endoscopy revealed normal esophagus in 68.2% of patients, esophagitis in 7.3%, and columnar-lined esophagus in 24.5%. Histology revealed normal mucosa in 50.3% of patients, esophagitis in 23.2%, gastric metaplasia in 17.2%, and BE in 6.6% (at a median age of 31.6 years). A history of fundoplication surgery was associated with BE (P = .03). Three ESCCs developed, in 2 men, at ages 42, 44, and 60 years. This corresponded to a prevalence of 0.7% in patients with esophageal atresia-a value 108-fold higher than in the same age group in the general population.

CONCLUSIONS

The prevalence of BE is 4-fold higher in young adults with esophageal atresia, and the prevalence of ESCC is 108-fold higher than in the general population. This finding could have important implications for transition of young adults from pediatric care to adult gastroenterology departments to receive life-long endoscopic follow-up evaluation to facilitate early diagnosis of relevant lesions.

Four cancer cases after esophageal atresia repair: Time to start screening the upper gastrointestinal tract

Esophageal atresia (EA) is one of the most common congenital digestive malformations and requires surgical correction early in life. Dedicated centers have reported survival rates up to 95%. The most frequent comorbidities after EA repair are dysphagia (72%) and gastroesophageal reflux (GER) (67%). Chronic GER after EA repair might lead to mucosal damage, esophageal stricturing, Barrett’s esophagus and eventually esophageal adenocarcinoma. Several long-term follow-up studies found an increased risk of Barrett’s esophagus and esophageal carcinoma in EA patients, both at a relatively young age. Given these findings, the recent ESPGHAN-NASPGHAN guideline recommends routine endoscopy in adults born with EA. We report a series of four EA patients who developed a carcinoma of the gastrointestinal tract: three esophageal carcinoma and one colorectal carcinoma in a colonic interposition. These cases emphasize the importance of lifelong screening of the upper gastrointestinal tract in EA patients.

Esophageal achalasia: a risk factor for carcinoma. A systematic review and meta-analysis

Achalasia of the cardia is associated with an increased risk of esophageal carcinoma. The real burden of achalasia at the malignancy genesis is still a controversial issue. Therefore, there are no generally accepted recommendations on follow-up evaluation for achalasia patients. This study aims to estimate the risk of esophageal adenocarcinoma and squamous cell carcinoma in achalasia patients. We searched for association between carcinoma and esophageal achalasia in databases up to January 2017 to perform a systematic review and meta-analysis. A total of 1,046 studies were identified from search strategy, of which 40 were selected for meta-analysis. A cumulative number of 11,978 esophageal achalasia patients were evaluated. The incidence of squamous cell carcinoma was 312.4 (StDev 429.16) cases per 100,000 patient-years at risk. The incidence of adenocarcinoma was 21.23 (StDev 31.6) cases per 100,000 patient-years at risk. The prevalence for esophageal carcinoma was 28 carcinoma cases in 1,000 esophageal achalasia patients (CI 95% 2, 39). The prevalence for squamous cell carcinoma was 26 cases in 1,000 achalasia patients (CI 95% 18, 39) and for adenocarcinoma was 4 cases in 1,000 achalasia patients (CI 95% 3, 6).The absolute risk increase for squamous cell carcinoma was 308.1 and for adenocarcinoma was 18.03 cases per 100,000 patients per year. To the best of our knowledge, this is the first meta-analysis estimating the burden of achalasia as an esophageal cancer risk factor. The high increased risk rate for cancer in achalasia patients points to a strict endoscopic surveillance for these patients. Also, the increased risk for developing adenocarcinoma in achalasia patients suggests fundoplication after myotomy, to avoid esophageal reflux and Barret esophagus, a known risk factor for adenocarcinoma.

The noncolonic microbiome: does it really matter?

About 100 trillion microorganisms compose the microbiome of the gastrointestinal tract and are predominantly found within the colon. Until recently, few bacteria were thought to inhabit the normal healthy esophagus and stomach. However, contemporary studies using molecular techniques have contradicted these assumptions. In this review, we summarize the pertinent findings of these studies that demonstrate established, complex mixed-microbial communities within the foregut in both health and disease. These studies contribute to improved understanding of interactions between the host immunity and the microbiome that may ultimately allow for novel therapeutic targets.