RESUMO
Biological interpretation of untargeted LC-MS-based metabolomics data depends on accurate compound identification, but current techniques fall short of identifying most features that can be detected. The human fecal metabolome is complex, variable, incompletely annotated, and serves as an ideal matrix to evaluate novel compound identification methods. We devised an experimental strategy for compound annotation using multidimensional chromatography and semiautomated feature alignment and applied these methods to study the fecal metabolome in the context of fecal microbiota transplantation (FMT) for recurrent C. difficile infection. Pooled fecal samples were fractionated using semipreparative liquid chromatography and analyzed by an orthogonal LC-MS/MS method. The resulting spectra were searched against commercial, public, and local spectral libraries, and annotations were vetted using retention time alignment and prediction. Multidimensional chromatography yielded more than a 2-fold improvement in identified compounds compared to conventional LC-MS/MS and successfully identified several rare and previously unreported compounds, including novel fatty-acid conjugated bile acid species. Using an automated software-based feature alignment strategy, most metabolites identified by the new approach could be matched to features that were detected but not identified in single-dimensional LC-MS/MS data. Overall, our approach represents a powerful strategy to enhance compound identification and biological insight from untargeted metabolomics data.
Assuntos
Transplante de Microbiota Fecal , Fezes , Metaboloma , Metabolômica , Espectrometria de Massas em Tandem , Humanos , Fezes/microbiologia , Fezes/química , Cromatografia Líquida/métodos , Metabolômica/métodos , Espectrometria de Massas em Tandem/métodos , Infecções por Clostridium/microbiologia , Infecções por Clostridium/metabolismo , Clostridioides difficile/metabolismo , Ácidos e Sais Biliares/metabolismo , Ácidos e Sais Biliares/análise , Espectrometria de Massa com Cromatografia LíquidaRESUMO
BACKGROUND AND AIMS: Alpha-gal allergy causes a delayed reaction to mammalian meats and has been reported worldwide. Patients with the allergy may present with isolated gastrointestinal (GI) symptoms, but this phenotype is poorly understood. METHODS: We pooled and analyzed symptoms and demographics of patients from two prospective cohorts of patients with a diagnosis of alpha-gal allergy who reacted after eating mammalian meat under observation. We compared the characteristics of patients who demonstrated GI-isolated symptoms on a challenge with those who exhibited symptoms outside the GI tract (skin, respiratory, and circulatory). RESULTS: Among the 91 children and adult alpha-gal allergic patients who exhibited symptoms after oral challenge with mammalian meat, 72.5% experienced GI distress with one or more GI symptoms, which was the most frequent class of symptoms, compared with skin changes in 57.1% and respiratory distress in 5.5%. The most common GI symptoms were abdominal pain (71%) and vomiting (22.0%). GI-isolated symptoms occurred in 37 patients (40.7%) who reacted, and those patients reacted more quickly than patients who exhibited systemic symptoms (median onset of symptoms in GI-isolated group 90 min vs 120 min) and were more likely to be children than adults (relative risk=1.94, 95% CI: 1.04-3.63). CONCLUSIONS: Isolated-GI distress occurred in 4 in every 10 alpha-gal allergic individuals who developed symptoms on oral food challenge with mammalian meat. Alpha-gal allergic patients, particularly children, may exhibit GI distress alone, and adult and pediatric gastroenterologists should be aware of the diagnosis and management of the allergy.
Assuntos
Dispepsia , Hipersensibilidade Alimentar , Adulto , Criança , Animais , Humanos , Estudos Prospectivos , Imunoglobulina E , Hipersensibilidade Alimentar/diagnóstico , Carne/efeitos adversos , MamíferosRESUMO
DESCRIPTION: Alpha-gal syndrome is an emerging allergy first described in the early 2000s. The allergy can cause anaphylaxis, gastrointestinal (GI) symptoms, and skin changes one to several hours after ingestion of mammalian products. A GI phenotype that is increasingly recognized manifests with nonspecific symptoms like abdominal pain, diarrhea, nausea or vomiting without predominant skin, respiratory or circulatory symptoms. Though the syndrome has been reported on all continents except Antarctica, in the United States most reports are within the range of the Lone Star tick, extending from New York and Iowa to Texas and Florida. The purpose of this AGA Clinical Practice Update (CPU) Commentary is to increase awareness among gastroenterologists about the presentation and management of alpha-gal syndrome. METHODS: This CPU commentary was commissioned and approved by the AGA Institute Clinical Practice Updates Committee (CPUC) and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership and underwent internal peer review by the CPUC and external peer review through standard procedures of Clinical Gastroenterology and Hepatology. This expert commentary incorporates important as well as recently published studies in this field, and it reflects the experiences of the authors. Formal ratings regarding the quality of evidence or strength of the presented considerations were not included since systematic reviews were not performed.
Assuntos
Hipersensibilidade Alimentar , Gastroenterologia , Gastroenteropatias , Animais , Humanos , Estados Unidos , Gastroenteropatias/diagnóstico , Gastroenteropatias/terapia , MamíferosRESUMO
Bile acids play key roles in nutrient uptake, inflammation, signaling, and microbiome composition. While previous bile acid analyses have primarily focused on profiling 5 canonical primary and secondary bile acids and their glycine and taurine amino acid-bile acid (AA-BA) conjugates, recent studies suggest that many other microbial conjugated bile acids (or MCBAs) exist. MCBAs are produced by the gut microbiota and serve as biomarkers, providing information about early disease onset and gut health. Here we analyzed 8 core bile acids synthetically conjugated with 22 proteinogenic and nonproteogenic amino acids totaling 176 MCBAs. Since many of the conjugates were isomeric and only 42 different m/z values resulted from the 176 MCBAs, a platform coupling liquid chromatography, ion mobility spectrometry, and mass spectrometry (LC-IMS-MS) was used for their separation. Their molecular characteristics were then used to create an in-house extended bile acid library for a combined total of 182 unique compounds. Additionally, â¼250 rare bile acid extracts were also assessed to provide additional resources for bile acid profiling and identification. This library was then applied to healthy mice dosed with antibiotics and humans having fecal microbiota transplantation (FMT) to assess the MCBA presence and changes in the gut before and after each perturbation.
Assuntos
Aminoácidos , Ácidos e Sais Biliares , Humanos , Camundongos , Animais , Isomerismo , Espectrometria de Massas , EsteroidesRESUMO
INTRODUCTION: Patients with alpha-gal syndrome, a delayed reaction to mammalian meat, can present with isolated gastrointestinal (GI) symptoms. We aimed to estimate the frequency of alpha-gal sensitization in a Southeastern US population and determine the association between sensitization and mammalian product dietary intake or GI symptoms. METHODS: We performed a cross-sectional study of participants who underwent a screening colonoscopy at our center between 2013 and 2015. We quantified serum alpha-gal immunoglobulin E antibodies in participants who were prospectively enrolled at screening colonoscopy and compared diet intake and lower GI symptoms reported in standardized questionnaires among those with elevated versus no alpha-gal IgE antibodies. RESULTS: Alpha-gal IgE antibodies were common-31.4% of screening colonoscopy participants (127 of 404) had elevated serum alpha-gal IgE >0.1 kU/L. Alpha-gal-sensitized participants endorsed similar rates of abdominal pain compared with those without alpha-gal antibodies (33% vs 38%, adjusted odds ratio 0.9, 95% confidence interval 0.7-1.3). Mammalian meat consumption did not differ based on alpha-gal sensitization status (average 1.43 servings/d in sensitized subjects vs 1.50 in alpha-gal IgE-negative subjects, P = 0.9). Alpha-gal-sensitized participants with levels ≥10 (n = 21) were overrepresented in the lowest quartiles of mammalian meat consumption, but not among those with GI symptoms in general. Participants with high alpha-gal antibody levels >2 kU/L (n = 45) or ≥10 U/L (n = 21) did not have a reduced mean daily mammalian meat intake compared with seronegative people. DISCUSSION: Elevated alpha-gal IgE antibodies were common and not associated with a reduced mammalian meat intake, abdominal pain, or diarrhea. Seropositivity did not predict symptomatic alpha-gal sensitization in this general screening population. Other host factors likely contribute to the phenotypic expression of alpha-gal syndrome.
Assuntos
Alérgenos , Hipersensibilidade Alimentar , Animais , Humanos , Estudos Transversais , Hipersensibilidade Alimentar/diagnóstico , Hipersensibilidade Alimentar/epidemiologia , Carne/efeitos adversos , Imunoglobulina E , Dor Abdominal/epidemiologia , Dor Abdominal/etiologia , MamíferosRESUMO
PURPOSE OF REVIEW: Food allergies are typically not considered as a cause of gastrointestinal (GI) distress without additional allergic symptoms, apart from celiac disease and eosinophilic esophagitis. However, recent reports of patients with alpha-gal syndrome who presented with GI-only symptoms like abdominal pain, vomiting, and diarrhea challenge this paradigm. Alpha-gal syndrome is an IgE-mediated allergy characterized by delayed reactions after eating mammalian meat or mammalian-derived products that contain galactose-alpha-1,3-galactose (alpha-gal). The purpose of this review is to discuss our current understanding of food allergies, GI illness, and the GI manifestations of alpha-gal syndrome. RECENT FINDINGS: Among Southeastern U.S. GI clinic patients who screened positive for serum alpha-gal IgE, a majority of patients reported significant symptom improvement on an alpha-gal-avoidant diet, suggesting that the allergy had played a role in their GI symptoms. Diagnosis of alpha-gal syndrome is typically made with concerning allergic symptoms, elevated alpha-gal specific IgE in the serum, and symptom improvement on an alpha-gal avoidant diet. Alpha-gal syndrome can cause a delayed allergic response that is increasingly recognized worldwide, including among patients with predominant GI symptoms.
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Hipersensibilidade Alimentar , Gastroenterologistas , Animais , Humanos , Galactose , Imunoglobulina E , Hipersensibilidade Alimentar/complicações , Hipersensibilidade Alimentar/diagnóstico , Síndrome , MamíferosRESUMO
We analyzed our challenging experience with a randomized controlled trial of misoprostol for prevention of recurrent C. difficile. Despite careful prescreening and thoughtful protocol modifications to facilitate enrollment, we closed the study early after enrolling just 7 participants over 3 years. We share lessons learned, noting the importance of feasibility studies, inclusion of biomarker outcomes, and dissemination of such findings to inform future research design and implementation successes.
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COVID-19 , Clostridioides difficile , Infecções por Clostridium , Misoprostol , Humanos , COVID-19/prevenção & controle , Misoprostol/uso terapêutico , Clostridioides , Estudos de Viabilidade , Infecções por Clostridium/prevenção & controleRESUMO
Targeted PCR amplification and high-throughput sequencing (amplicon sequencing) of 16S rRNA gene fragments is widely used to profile microbial communities. New long-read sequencing technologies can sequence the entire 16S rRNA gene, but higher error rates have limited their attractiveness when accuracy is important. Here we present a high-throughput amplicon sequencing methodology based on PacBio circular consensus sequencing and the DADA2 sample inference method that measures the full-length 16S rRNA gene with single-nucleotide resolution and a near-zero error rate. In two artificial communities of known composition, our method recovered the full complement of full-length 16S sequence variants from expected community members without residual errors. The measured abundances of intra-genomic sequence variants were in the integral ratios expected from the genuine allelic variants within a genome. The full-length 16S gene sequences recovered by our approach allowed Escherichia coli strains to be correctly classified to the O157:H7 and K12 sub-species clades. In human fecal samples, our method showed strong technical replication and was able to recover the full complement of 16S rRNA alleles in several E. coli strains. There are likely many applications beyond microbial profiling for which high-throughput amplicon sequencing of complete genes with single-nucleotide resolution will be of use.
Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Microbiota/genética , Filogenia , RNA Ribossômico 16S/genética , Escherichia coli K12/classificação , Escherichia coli K12/genética , Escherichia coli O157/classificação , Escherichia coli O157/genética , Fezes/microbiologia , Humanos , Reação em Cadeia da Polimerase/métodos , Polimorfismo de Nucleotídeo Único/genética , Análise de Sequência de DNARESUMO
BACKGROUND & AIMS: Despite the availability of endoscopic therapy, many patients in the United States undergo surgical resection for nonmalignant colorectal polyps. We aimed to quantify and examine trends in the use of surgery for nonmalignant colorectal polyps in a nationally representative sample. METHODS: We analyzed data from the Healthcare Cost and Utilization Project National Inpatient Sample for 2000 through 2014. We included all adult patients who underwent elective colectomy or proctectomy and had a diagnosis of either nonmalignant colorectal polyp or colorectal cancer. We compared trends in surgery for nonmalignant colorectal polyps with surgery for colorectal cancer and calculated age, sex, race, region, and teaching status/bed-size-specific incidence rates of surgery for nonmalignant colorectal polyps. RESULTS: From 2000 through 2014, there were 1,230,458 surgeries for nonmalignant colorectal polyps and colorectal cancer in the United States. Among those surgeries, 25% were performed for nonmalignant colorectal polyps. The incidence of surgery for nonmalignant colorectal polyps has increased significantly, from 5.9 in 2000 to 9.4 in 2014 per 100,000 adults (incidence rate difference, 3.56; 95% confidence interval 3.40-3.72), while the incidence of surgery for colorectal cancer has significantly decreased, from 31.5 to 24.7 surgeries per 100,000 adults (incidence rate difference, -6.80; 95% confidence interval -7.11 to -6.49). The incidence of surgery for nonmalignant colorectal polyps has been increasing among individuals age 20 to 79, in men and women and including all races and ethnicities. CONCLUSIONS: In an analysis of a large, nationally representative sample, we found that surgery for nonmalignant colorectal polyps is common and has significantly increased over the past 14 years.
Assuntos
Colectomia/tendências , Pólipos do Colo/cirurgia , Neoplasias Colorretais/cirurgia , Pólipos Intestinais/cirurgia , Padrões de Prática Médica/tendências , Doenças Retais/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Colectomia/estatística & dados numéricos , Pólipos do Colo/etnologia , Pólipos do Colo/patologia , Neoplasias Colorretais/epidemiologia , Neoplasias Colorretais/patologia , Bases de Dados Factuais , Feminino , Humanos , Incidência , Pólipos Intestinais/etnologia , Pólipos Intestinais/patologia , Masculino , Pessoa de Meia-Idade , Doenças Retais/etnologia , Doenças Retais/patologia , Fatores de Tempo , Estados Unidos/epidemiologia , Adulto JovemAssuntos
Hipersensibilidade Alimentar/complicações , Hipersensibilidade Alimentar/dietoterapia , Dor Abdominal/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Amblyomma , Anafilaxia/etiologia , Animais , Diarreia/etiologia , Feminino , Hipersensibilidade Alimentar/sangue , Humanos , Imunoglobulina E/sangue , Masculino , Pessoa de Meia-Idade , Náusea/etiologia , Estudos Retrospectivos , Picadas de Carrapatos/complicações , Picadas de Carrapatos/imunologiaRESUMO
BACKGROUND & AIMS: Nonpolypoid colorectal neoplasms (NP-CRNs) are more likely to contain high-grade dysplasia or early-stage cancer than polypoid neoplasms. We aimed to determine the long-term outcomes of patients with at least 1 NP-CRN. METHODS: We performed a longitudinal cohort study of 4454 patients at a Veterans' Affairs hospital who underwent colonoscopy from 2000 through 2005; 341 were found to have 1 or more NP-CRNs and were matched (3:1) with patients found to have 1 or more polypoid neoplasms (controls, n = 1025). We collected and analyzed data on baseline colonoscopy findings and first follow-up colonoscopy results through August 2014. We calculated the incidence of advanced neoplasia at first follow-up colonoscopy, as defined by the presence of ≥1 tubular or sessile serrated adenomas ≥10 mm in diameter, tubulovillous adenoma, high-grade dysplasia, or invasive cancer. RESULTS: A significantly higher proportion of patients with 1 or more NP-CRNs (16.0%) were found to have advanced neoplasia at their first follow-up colonoscopy than controls (8.6%); the adjusted risk ratio was 1.6 (95% confidence interval, 1.05-2.6; P = .03). A significantly higher proportion of patients with 1 or more NP-CRNs were found to have additional NP-CRNs at the follow-up colonoscopy (17%) than controls (7%; relative risk, 2.3; 95% confidence interval, 1.5-3.5; P < .001). Similar proportions of patients in each group developed cancers after colonoscopy. CONCLUSIONS: In a longitudinal cohort study, we found that patients with NP-CRN were more likely to develop additional NP-CRNs and to have advanced neoplasms at their first follow-up colonoscopy than patients with only polypoid neoplasms. However, patients with NP-CRN were not more likely to develop cancers after colonoscopy when surveillance guidelines were followed. Larger studies are needed to determine risk of colorectal cancer in patients with NP-CRN.
Assuntos
Neoplasias Colorretais/patologia , Pólipos/patologia , Idoso , Colonoscopia , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-IdadeAssuntos
Betacoronavirus , Competência Clínica , Simulação por Computador , Infecções por Coronavirus/complicações , Doenças do Sistema Digestório/diagnóstico , Educação de Pós-Graduação em Medicina/métodos , Gastroenterologistas/educação , Pneumonia Viral/complicações , COVID-19 , Infecções por Coronavirus/epidemiologia , Doenças do Sistema Digestório/complicações , Humanos , Pandemias , Pneumonia Viral/epidemiologia , SARS-CoV-2RESUMO
BACKGROUND AND STUDY AIMS: The learning curve for optical diagnosis of colorectal polyps with the narrow-band imaging (NBI) is unknown. To forego histological analysis of diminutive polyps diagnosed optically with high confidence, guidelines recommend ≥â90â% negative predictive value (NPV) and concordance of ≥â90â% for surveillance intervals predicted optically and histologically. We aimed to study the learning of optical diagnosis for colorectal polyps. PATIENTS AND METHODS: We studied five endoscopists as part of a randomized multisite trial comparing near-focus and standard-focus views for optical diagnosis. They trained using a computer-based module, followed by 10 real-time colonoscopies with pathology correlation. Endoscopists then optically diagnosed and resected all the polyps found during 558 consecutive colonoscopies, and diagnoses were compared with pathology. Endoscopists repeated the training module at the study midpoint. NPV and concordance of surveillance intervals for diminutive polyps diagnosed optically with high confidence were measured over time. RESULTS: Endoscopists showed high diagnostic performance, with a nonsignificant trend toward higher NPV in the second half of the study. For the 445 polyps in the standard-view arm, the NPV was 88.0â% (95â%CI 75.7â%â-â95.5â%) in the first half and 95.8â% (88.3â%â-â99.1â%) in the second; Pâ=â0.7.âThree endoscopists in the first half and four in the second achievedâ>â90â% NPV. Concordance of surveillance intervals was identical in the first and second halves at 98.1â% (95â%CI 93.3â%â-â99.8â%). CONCLUSIONS: High NPV for the prediction of non-neoplasms with NBI was achieved and maintained in this group of endoscopists who participated in standardized and continued training. Both NPV and surveillance interval agreement indicated high performance in the optical diagnosis of colorectal polyps and exceeded thresholds.
Assuntos
Adenoma/diagnóstico , Competência Clínica , Pólipos do Colo/diagnóstico , Colonoscopia , Neoplasias Colorretais/diagnóstico , Educação Médica Continuada , Imagem de Banda Estreita/normas , Adenoma/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Pólipos do Colo/patologia , Neoplasias Colorretais/patologia , Simulação por Computador , Feminino , Humanos , Curva de Aprendizado , Masculino , Memória Episódica , Pessoa de Meia-Idade , Imagem de Banda Estreita/métodos , Vigilância da População , Valor Preditivo dos Testes , Método Simples-CegoRESUMO
PURPOSE: Many studies have reported on the use of narrow band imaging (NBI) colonoscopy to differentiate neoplastic from non-neoplastic colorectal polyps. It has potential to replace pathological diagnosis of diminutive polyps. We aimed to perform a systematic review and meta-analysis on the real-time diagnostic operating characteristics of NBI colonoscopy. METHODS: We searched PubMed, SCOPUS and Cochrane databases and abstracts. We used a two-level bivariate meta-analysis following a random effects model to summarise the data and fit hierarchical summary receiver-operating characteristic (HSROC) curves. The area under the HSROC curve serves as an indicator of the diagnostic test strength. We calculated summary sensitivity, specificity and negative predictive value (NPV). We assessed agreement of surveillance interval recommendations based on endoscopic diagnosis compared to pathology. RESULTS: For NBI diagnosis of colorectal polyps, the area under the HSROC curve was 0.92 (95% CI 0.90 to 0.94), based on 28 studies involving 6280 polyps in 4053 patients. The overall sensitivity was 91.0% (95% CI 87.6% to 93.5%) and specificity was 82.6% (95% CI 79.0% to 85.7%). In eight studies (n=2146 polyps) that used high-confidence diagnostic predictions, sensitivity was 93.8% and specificity was 83.3%. The NPVs exceeded 90% when 60% or less of all polyps were neoplastic. Surveillance intervals based on endoscopic diagnosis agreed with those based on pathology in 92.6% of patients (95% CI 87.9% to 96.3%). CONCLUSIONS: NBI diagnosis of colorectal polyps is highly accurate--the area under the HSROC curve exceeds 0.90. High-confidence predictions provide >90% sensitivity and NPV. It shows high potential for real-time endoscopic diagnosis.