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1.
Am J Gastroenterol ; 2024 May 10.
Article in English | MEDLINE | ID: mdl-38587280

ABSTRACT

INTRODUCTION: Endoscopic eradication therapy (EET) combining endoscopic resection (ER) with endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) followed by ablation is the standard of care for the treatment of dysplastic Barrett's esophagus (BE). We have previously shown comparable rates of complete remission of intestinal metaplasia (CRIM) with both approaches. However, data comparing recurrence after CRIM are lacking. We compared rates of recurrence after CRIM with both techniques in a multicenter cohort. METHODS: Patients undergoing EET achieving CRIM at 3 academic institutions were included. Demographic and clinical data were abstracted. Outcomes included rates and predictors of any BE and dysplastic BE recurrence in the 2 groups. Cox-proportional hazards models and inverse probability treatment weighting (IPTW) analysis were used for analysis. RESULTS: A total of 621 patients (514 EMR and 107 ESD) achieving CRIM were included in the recurrence analysis. The incidence of any BE (15.7, 5.7 per 100 patient-years) and dysplastic BE recurrence (7.3, 5.3 per 100 patient-years) were comparable in the EMR and ESD groups, respectively. On multivariable analyses, the chances of BE recurrence were not influenced by ER technique (hazard ratio 0.87; 95% confidence interval 0.51-1.49; P = 0.62), which was also confirmed by IPTW analysis (ESD vs EMR: hazard ratio 0.98; 95% confidence interval 0.56-1.73; P = 0.94). BE length, lesion size, and history of cigarette smoking were independent predictors of BE recurrence. DISCUSSION: Patients with BE dysplasia/neoplasia achieving CRIM, initially treated with EMR/ablation, had comparable recurrence rates to ESD/ablation. Randomized trials are needed to confirm these outcomes between the 2 ER techniques.

4.
Dig Dis Sci ; 69(1): 246-253, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37914889

ABSTRACT

BACKGROUND: Limited data are available on the epidemiology of gastroesophageal junction adenocarcinoma (GEJAC), particularly in comparison to esophageal adenocarcinoma (EAC). With the advent of molecular non-endoscopic Barrett's esophagus (BE) detection tests which sample the esophagus and gastroesophageal junction, early detection of EAC and GEJAC has become a possibility and their epidemiology has gained importance. AIMS: We sought to evaluate time trends in the epidemiology and survival of patients with EAC and GEJAC in a population-based cohort. METHODS: EAC and GEJAC patients from 1976 to 2019 were identified using ICD 9 and 10 diagnostic codes from the Rochester Epidemiology Project (REP). Clinical data and survival status were abstracted. Poisson regression was used to calculate incidence rate ratios (IRR). Survival analysis and Cox proportional models were used to assess predictors of survival. RESULTS: We included 443 patients (287 EAC,156 GEJAC). The incidence of EAC and GEJAC during 1976-2019 was 1.40 (CI 1.1-1.74) and 0.83 (CI 0.61-1.11) per 100,000 people, respectively. There was an increase in the incidence of EAC (IRR = 2.45, p = 0.011) and GEJAC (IRR = 3.17, p = 0.08) from 2000 to 2004 compared to 1995-1999, plateauing in later time periods. Most patients had associated BE and presented at advanced stages, leading to high 5-year mortality rates (66% in EAC and 59% in GEJAC). Age and stage at diagnosis were predictors of mortality. CONCLUSION: The rising incidence of EAC/GEJAC appears to have plateaued somewhat in the last decade. However, both cancers present at advanced stages with persistently poor survival, underscoring the need for early detection.


Subject(s)
Adenocarcinoma , Barrett Esophagus , Esophageal Neoplasms , Humans , Esophageal Neoplasms/diagnosis , Esophageal Neoplasms/epidemiology , Esophageal Neoplasms/etiology , Barrett Esophagus/diagnosis , Barrett Esophagus/epidemiology , Barrett Esophagus/complications , Adenocarcinoma/pathology , Esophagogastric Junction/pathology
5.
Clin Gastroenterol Hepatol ; 22(6): 1170-1180, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38154727

ABSTRACT

Significant advances in artificial intelligence (AI) over the past decade potentially may lead to dramatic effects on clinical practice. Digitized histology represents an area ripe for AI implementation. We describe several current needs within the world of gastrointestinal histopathology, and outline, using currently studied models, how AI potentially can address them. We also highlight pitfalls as AI makes inroads into clinical practice.


Subject(s)
Artificial Intelligence , Gastrointestinal Diseases , Humans , Gastrointestinal Diseases/pathology , Gastrointestinal Diseases/diagnosis , Gastrointestinal Tract/pathology , Histocytochemistry/methods
6.
Clin Transl Gastroenterol ; 14(10): e00637, 2023 10 01.
Article in English | MEDLINE | ID: mdl-37698203

ABSTRACT

INTRODUCTION: Screening for Barrett's esophagus (BE) is suggested in those with risk factors, but remains underutilized. BE/esophageal adenocarcinoma (EAC) risk prediction tools integrating multiple risk factors have been described. However, accuracy remains modest (area under the receiver-operating curve [AUROC] ≤0.7), and clinical implementation has been challenging. We aimed to develop machine learning (ML) BE/EAC risk prediction models from an electronic health record (EHR) database. METHODS: The Clinical Data Analytics Platform, a deidentified EHR database of 6 million Mayo Clinic patients, was used to predict BE and EAC risk. BE and EAC cases and controls were identified using International Classification of Diseases codes and augmented curation (natural language processing) techniques applied to clinical, endoscopy, laboratory, and pathology notes. Cases were propensity score matched to 5 independent randomly selected control groups. An ensemble transformer-based ML model architecture was used to develop predictive models. RESULTS: We identified 8,476 BE cases, 1,539 EAC cases, and 252,276 controls. The BE ML transformer model had an overall sensitivity, specificity, and AUROC of 76%, 76%, and 0.84, respectively. The EAC ML transformer model had an overall sensitivity, specificity, and AUROC of 84%, 70%, and 0.84, respectively. Predictors of BE and EAC included conventional risk factors and additional novel factors, such as coronary artery disease, serum triglycerides, and electrolytes. DISCUSSION: ML models developed on an EHR database can predict incident BE and EAC risk with improved accuracy compared with conventional risk factor-based risk scores. Such a model may enable effective implementation of a minimally invasive screening technology.


Subject(s)
Adenocarcinoma , Barrett Esophagus , Esophageal Neoplasms , Humans , Barrett Esophagus/diagnosis , Barrett Esophagus/pathology , Electronic Health Records , Esophageal Neoplasms/diagnosis , Esophageal Neoplasms/epidemiology , Esophageal Neoplasms/pathology , Adenocarcinoma/diagnosis , Adenocarcinoma/epidemiology , Adenocarcinoma/pathology , Machine Learning
7.
Gastroenterol Clin North Am ; 51(3): 457-484, 2022 09.
Article in English | MEDLINE | ID: mdl-36153105

ABSTRACT

Esophageal squamous cell carcinoma (ESCC) is common in the developing world with decreasing incidence in developed countries and carries significant morbidity and mortality. Major risk factors for ESCC development include significant use of alcohol and tobacco. Screening for ESCC can be recommended in high-risk populations living in highly endemic regions. The treatment of ESCC ranges from endoscopic resection therapy or surgery in localized disease to chemoradiotherapy in metastatic disease, and prognosis is directly related to the stage at diagnosis. New immunotherapies and molecular targeted therapies may improve the dismal survival outcomes in patients with metastatic ESCC.


Subject(s)
Carcinoma, Squamous Cell , Esophageal Neoplasms , Esophageal Squamous Cell Carcinoma , Carcinoma, Squamous Cell/diagnosis , Carcinoma, Squamous Cell/etiology , Carcinoma, Squamous Cell/therapy , Chemoradiotherapy/adverse effects , Esophageal Neoplasms/diagnosis , Esophageal Neoplasms/etiology , Esophageal Neoplasms/therapy , Esophageal Squamous Cell Carcinoma/diagnosis , Esophageal Squamous Cell Carcinoma/etiology , Esophageal Squamous Cell Carcinoma/therapy , Esophagectomy/adverse effects , Humans , Neoadjuvant Therapy/adverse effects , Prognosis , Retrospective Studies
8.
Gastrointest Endosc ; 96(6): 918-925.e3, 2022 12.
Article in English | MEDLINE | ID: mdl-35718071

ABSTRACT

BACKGROUND AND AIMS: The risk of progression in Barrett's esophagus (BE) increases with development of dysplasia. There is a critical need to improve the diagnosis of BE dysplasia, given substantial interobserver disagreement among expert pathologists and overdiagnosis of dysplasia by community pathologists. We developed a deep learning model to predict dysplasia grade on whole-slide imaging. METHODS: We digitized nondysplastic BE (NDBE), low-grade dysplasia (LGD), and high-grade dysplasia (HGD) histology slides. Two expert pathologists confirmed all histology and digitally annotated areas of dysplasia. Training, validation, and test sets were created (by a random 70/20/10 split). We used an ensemble approach combining a "you only look once" model to identify regions of interest and histology class (NDBE, LGD, or HGD) followed by a ResNet101 model pretrained on ImageNet applied to the regions of interest. Diagnostic performance was determined for the whole slide. RESULTS: We included slides from 542 patients (164 NDBE, 226 LGD, and 152 HGD) yielding 8596 bounding boxes in the training set, 1946 bounding boxes in the validation set, and 840 boxes in the test set. When the ensemble model was used, sensitivity and specificity for LGD was 81.3% and 100%, respectively, and >90% for NDBE and HGD. The overall positive predictive value and sensitivity metric (calculated as F1 score) was .91 for NDBE, .90 for LGD, and 1.0 for HGD. CONCLUSIONS: We successfully trained and validated a deep learning model to accurately identify dysplasia on whole-slide images. This model can potentially help improve the histologic diagnosis of BE dysplasia and the appropriate application of endoscopic therapy.


Subject(s)
Adenocarcinoma , Barrett Esophagus , Deep Learning , Esophageal Neoplasms , Humans , Barrett Esophagus/diagnosis , Barrett Esophagus/pathology , Esophageal Neoplasms/pathology , Adenocarcinoma/pathology , Disease Progression , Hyperplasia
9.
Clin Gastroenterol Hepatol ; 20(12): 2772-2779.e8, 2022 12.
Article in English | MEDLINE | ID: mdl-35217151

ABSTRACT

BACKGROUND & AIMS: Prediction of progression risk in Barrett's esophagus (BE) may enable personalized management. We aimed to assess the adjunct value of a tissue systems pathology test (TissueCypher) performed on paraffin-embedded biopsy tissue, when added to expert pathology review in predicting incident progression, pooling individual patient-level data from multiple international studies METHODS: Demographics, clinical features, the TissueCypher risk class/score, and progression status were analyzed. Conditional logistical regression analysis was used to develop multivariable models predicting incident progression with and without the TissueCypher risk class (low, intermediate, high). Concordance (c-) statistics were calculated and compared with likelihood ratio tests to assess predictive ability of models. A risk prediction calculator integrating clinical variables and TissueCypher risk class was also developed. RESULTS: Data from 552 patients with baseline no (n = 472), indefinite (n = 32), or low-grade dysplasia (n = 48) (comprising 152 incident progressors and 400 non-progressors) were analyzed. A high-risk test class independently predicted increased risk of progression to high-grade dysplasia/adenocarcinoma (odds ratio, 6.0; 95% confidence interval, 2.9-12.0), along with expert confirmed low-grade dysplasia (odds ratio, 2.9; 95% confidence interval, 1.2-7.2). Model prediction of progression with the TissueCypher risk class incorporated was significantly superior than without, in the whole cohort (c-statistic 0.75 vs 0.68; P < .0001) and the nondysplastic BE subset (c-statistic 0.72 vs 0.63; P < .0001). Sensitivity and specificity of the high risk TissueCypher class were 38% and 94%, respectively. CONCLUSIONS: An objective tissue systems pathology test high-risk class is a strong independent predictor of incident progression in patients with BE, substantially improving progression risk prediction over clinical variables alone. Although test specificity was high, sensitivity was modest.


Subject(s)
Adenocarcinoma , Barrett Esophagus , Esophageal Neoplasms , Precancerous Conditions , Humans , Barrett Esophagus/diagnosis , Barrett Esophagus/pathology , Esophageal Neoplasms/diagnosis , Esophageal Neoplasms/epidemiology , Esophageal Neoplasms/pathology , Precancerous Conditions/pathology , Disease Progression , Adenocarcinoma/pathology
10.
Clin Gastroenterol Hepatol ; 20(12): 2929, 2022 Dec.
Article in English | MEDLINE | ID: mdl-35218952
11.
Clin Gastroenterol Hepatol ; 20(1): 65-73.e1, 2022 01.
Article in English | MEDLINE | ID: mdl-33220523

ABSTRACT

BACKGROUND & AIMS: Endoscopic resection is an important component of the endoscopic treatment of Barrett's esophagus (BE) with dysplasia and intramucosal adenocarcinoma. Endoscopic resection can be performed by cap-assisted endoscopic mucosal resection (cEMR) or endoscopic submucosal dissection (ESD). We compared the histologic outcomes of ESD vs cEMR, followed by ablation. METHODS: We queried a prospectively maintained database of all patients undergoing cEMR and ESD followed by ablation at our institution from January 2006 to March 2020 and abstracted relevant demographic and clinical data. Our primary outcomes included the rate of complete remission of dysplasia (CRD): absence of dysplasia on surveillance histology, and complete remission of intestinal metaplasia (CRIM): absence of intestinal metaplasia. Our secondary outcome included complication rates. RESULTS: We included 537 patients in the study: 456 underwent cEMR and 81 underwent ESD. The cumulative probabilities of CRD at 2 years were 75.8% and 85.6% in the cEMR and ESD groups, respectively (P < .01). Independent predictors of CRD were as follows: ESD (hazard ratio [HR], 2.38; P < .01) and shorter BE segment length (HR, 1.11; P < .01). The cumulative probabilities of CRIM at 2 years were 59.3% and 50.6% in the cEMR and ESD groups, respectively (P > .05). The only independent predictor of CRIM was a shorter BE segment (HR, 1.16; P < .01). CONCLUSIONS: BE patients with dysplasia or intramucosal adenocarcinoma undergoing ESD reach CRD at higher rates than those treated with cEMR, although CRIM rates at 2 years and complication rates were similar between the 2 groups.


Subject(s)
Adenocarcinoma , Barrett Esophagus , Endoscopic Mucosal Resection , Esophageal Neoplasms , Adenocarcinoma/pathology , Barrett Esophagus/complications , Endoscopic Mucosal Resection/adverse effects , Esophageal Neoplasms/pathology , Esophagoscopy , Humans
12.
Gastrointest Endosc ; 95(1): 51-59.e7, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34543648

ABSTRACT

BACKGROUND AND AIMS: Seattle protocol forceps biopsy sampling (FB) is currently recommended for surveillance in Barrett's esophagus (BE) but limited by sampling error and lack of compliance. Wide-area transepithelial sampling with 3-dimensional analysis (WATS3D; CDx Diagnostics, Suffern, NY, USA) is reported to increase BE dysplasia detection. We assessed the incremental yield and clinical significance of WATS3D for dysplasia detection over FB in a systematic review and meta-analysis. METHODS: We queried major scientific databases for studies using WATS3D and FB from 2000 to 2020. The primary outcome was the incremental yield of WATS3D-detected dysplasia (defined as a composite of indefinite for dysplasia, low- and high-grade dysplasia [HGD] and esophageal adenocarcinoma [EAC]) over FB. Secondary outcomes were incremental yields of HGD/EAC and rate of reconfirmation of WATS3D dysplasia on subsequent FB. RESULTS: Meta-analysis of 7 eligible studies demonstrated that FB diagnosed dysplasia in 15.9% of cases, whereas the incremental yield with WATS3D was 7.2% (95% confidence interval, 3.9%-11.5%; I2= 92.1%). Meta-analysis of 6 studies demonstrated that FB diagnosed HGD/EAC in 2.3% of patients, whereas the incremental yield with WATS3D was 2.1% (95% confidence interval, .4%-5.3%; I2= 92.7%). Notably, WATS3D was negative in 62.5% of cases where FB identified dysplasia. Two studies reported reconfirmation of WATS3D dysplasia with FB histology in only 20 patients. CONCLUSIONS: WATS3D increases dysplasia detection; however, the clinical significance of this increased dysplasia detection remains uncertain. Data from endoscopic follow-up to ascertain FB histology in patients with dysplasia based solely on WATS3D are needed to determine the optimal clinical application and significance of WATS3D-only dysplasia.


Subject(s)
Adenocarcinoma , Barrett Esophagus , Esophageal Neoplasms , Precancerous Conditions , Adenocarcinoma/diagnostic imaging , Barrett Esophagus/diagnostic imaging , Biopsy , Disease Progression , Esophageal Neoplasms/diagnostic imaging , Humans , Specimen Handling
13.
Gastrointest Endosc ; 95(3): 422-431.e2, 2022 03.
Article in English | MEDLINE | ID: mdl-34624303

ABSTRACT

BACKGROUND AND AIMS: Strong evidence supports the use of radiofrequency ablation (RFA) in the management of dysplastic/neoplastic Barrett's esophagus (BE). Recently, the efficacy of the cryoballoon ablation (CBA) system was demonstrated in multicenter cohort studies. We aimed to assess the comparative effectiveness and safety of these 2 ablation modalities for endoscopic eradication therapy (EET) in a cohort study. METHODS: Data were abstracted on patients with dysplastic BE or intramucosal carcinoma undergoing EET using RFA or CBA as the primary ablation modality at 2 referral centers. The primary outcome was the rate of complete remission intestinal metaplasia (CRIM). Secondary outcomes were rates of complete remission of dysplasia (CRD) and adverse events. Cox proportional hazards models and propensity scored-matched analyses were conducted to compare outcomes. RESULTS: Three hundred eleven patients (CBA, 85 patients; RFA, 226 patients) with a median follow-up of 1.5 years (interquartile range, .8, 2.5) in the RFA group and 2.0 years (interquartile range, 1.3, 2.5) in the CBA group were studied. On multivariable analyses, the chances of reaching CRD and CRIM were not influenced by ablation modality. Propensity score-matched analysis revealed a comparable chance of achieving CRIM (CBA vs RFA: hazard ratio, 1.24; 95% confidence interval, .79-1.96; P = .35) and CRD (CBA vs RFA: hazard ratio, 1.19; 95% confidence interval, .82-1.73; P = .36). The CBA group had a higher stricture rate compared with the RFA group (10.4% vs 4.4%, P = .04). CONCLUSIONS: Histologic outcomes of EET using CBA and RFA for dysplastic BE appear to be comparable. A randomized trial is needed to definitively compare outcomes between these 2 modalities.


Subject(s)
Barrett Esophagus , Catheter Ablation , Esophageal Neoplasms , Barrett Esophagus/pathology , Catheter Ablation/adverse effects , Cohort Studies , Esophageal Neoplasms/pathology , Esophagoscopy/adverse effects , Humans , Propensity Score , Treatment Outcome
15.
Clin Gastroenterol Hepatol ; 19(5): 922-929.e1, 2021 05.
Article in English | MEDLINE | ID: mdl-32707339

ABSTRACT

BACKGROUND & AIMS: It is a challenge to detect dysplasia in Barrett's esophagus (BE) and esophageal adenocarcinomas (EACs) are missed in 25%-33% of cases. The neoplasia detection rate (NDR), defined as the rate of high-grade dysplasia (HGD) or EAC detection during initial surveillance endoscopy, has been proposed as a quality metric for endoscopic evaluation of patients with BE. However, current estimates are from referral center cohorts, which might overestimate NDR. Effects on rates of missed dysplasia are also unknown. We analyzed data from a large cohort of patients with BE to estimate the NDR and factors associated with it, and assess the effects of the NDR on the rate of missed dysplasia. METHODS: We analyzed data from 1066 patients in the Rochester Epidemiology Project-linked medical record system, a population-based cohort of patients with BE (confirmed by review of the endoscopic and histologic reports) from 11 southeastern Minnesota counties from 1991 through 2019. Biopsies reported to contain dysplasia were confirmed by expert gastrointestinal pathologists. The NDR was calculated as the rate of HGD or EAC detected by histologic analyses of biopsies collected during the first surveillance endoscopy. Patients without HGD or EAC at their initial endoscopy (n = 391) underwent repeat endoscopy within 12 months; HGD or EAC detected at the repeat endoscopy were considered to be missed on index endoscopy. Factors associated with NDR and missed dysplasia were identified using univariate and multivariate logistic regression models. RESULTS: The NDR was 4.9% (95% CI, 3.8-6.4); 3.1% of patients had HGD, 1.8% had EAC, and 10.6% had low-grade dysplasia. Factors associated with higher rates of detection of neoplasia included older age, male sex, smoking, increasing length of BE, and surveillance endoscopies by gastroenterologists. This NDR was associated with a substantially lower rate of missed dysplasia (13%). CONCLUSIONS: In an analysis of 1066 patients with BE in a population-based cohort, we found a lower NDR and lower rate of missed dysplasia than previously reported. NDR may have value as a quality metric in BE surveillance if validated in other cohorts.


Subject(s)
Adenocarcinoma , Barrett Esophagus , Esophageal Neoplasms , Precancerous Conditions , Adenocarcinoma/diagnosis , Adenocarcinoma/epidemiology , Aged , Barrett Esophagus/diagnosis , Barrett Esophagus/epidemiology , Biopsy , Disease Progression , Esophageal Neoplasms/diagnosis , Esophageal Neoplasms/epidemiology , Humans , Hyperplasia , Male , Precancerous Conditions/diagnosis , Precancerous Conditions/epidemiology
16.
Clin Gastroenterol Hepatol ; 17(9): 1902-1903.e1, 2019 08.
Article in English | MEDLINE | ID: mdl-30342260

ABSTRACT

Esophageal lichen planus (ELP) is a chronic inflammatory process characterized by apoptotic activity of cytotoxic CD8+ T cells on basal keratinocytes as well as regulatory and helper T cells.1-3 Due to chronic inflammation, malignant transformation may be a concern and has been documented in case reports.4,5 We describe the occurrence of esophageal cancer in ELP patients from a large tertiary patient population.


Subject(s)
Esophageal Neoplasms/epidemiology , Esophageal Squamous Cell Carcinoma/epidemiology , Lichen Planus/epidemiology , Aged , Aged, 80 and over , Chemotherapy, Adjuvant , Deglutition Disorders , Disease Progression , Endoscopic Mucosal Resection , Endoscopy, Digestive System , Esophageal Diseases/drug therapy , Esophageal Diseases/epidemiology , Esophageal Diseases/pathology , Esophageal Neoplasms/physiopathology , Esophageal Neoplasms/therapy , Esophageal Squamous Cell Carcinoma/physiopathology , Esophageal Squamous Cell Carcinoma/therapy , Esophagectomy , Female , Glucocorticoids/therapeutic use , Humans , Immunosuppressive Agents/therapeutic use , Lichen Planus/drug therapy , Lichen Planus/pathology , Male , Middle Aged , Radiotherapy, Adjuvant , Risk Factors
17.
Mayo Clin Proc ; 92(6): 965-972, 2017 06.
Article in English | MEDLINE | ID: mdl-28578784

ABSTRACT

Evaluating a patient with dysphagia can be a complex and daunting task. In this article, we present a practical approach to the evaluation, physical examination, and subsequent work-up of dysphagia that is applicable to practicing physicians.


Subject(s)
Deglutition Disorders/diagnosis , Medical History Taking , Physical Examination/methods , Deglutition Disorders/therapy , Humans
18.
Abdom Radiol (NY) ; 42(2): 351-360, 2017 02.
Article in English | MEDLINE | ID: mdl-28078381

ABSTRACT

Celiac disease (CD) is an immune-mediated inflammatory enteropathy triggered by gluten exposure in genetically susceptible individuals. It has a high prevalence approaching 1% of the US population. A high index of suspicion is warranted to diagnose CD as frequently patients present with extraintestinal or atypical manifestations. CD is diagnosed by a combination of serum serologies and duodenal biopsies. The majority of patients will respond to a lifelong gluten-free diet which is the cornerstone of therapy. Complications such as refractory CD, ulcerative jejunoileitis, enteropathy associated T-cell lymphoma and small bowel adenocarcinoma occur in a minority of patients.


Subject(s)
Celiac Disease , Biopsy , Celiac Disease/complications , Celiac Disease/diagnosis , Celiac Disease/diet therapy , Celiac Disease/epidemiology , Diagnosis, Differential , Diagnostic Imaging , Diet, Gluten-Free , Humans , Prognosis
19.
J Breath Res ; 2(1): 017017, 2008 Mar.
Article in English | MEDLINE | ID: mdl-21386161

ABSTRACT

Gram negative anaerobic microbial degradation of proteins, peptides and amino acids in saliva leads to production of oral malodor. Volatile sulfur compounds (VSCs) from cysteine and indole/skatole (I/S) from tryptophan are two major components of breath odor. In this study, salivary mixed bacteria and oral pure cultures were compared for their ability to produce odor from cysteine, tryptophan and salivary supernatant. The VSC malodor inhibitor, zinc, was used to help identify the malodor processes involved. Salivary sediment and salivary supernatant were both obtained from wax-stimulated whole saliva. Gram positive (13) and Gram negative (12) oral pure cultures of common salivary bacteria were each grown in appropriate media and harvested. Incubation mixtures were prepared with salivary sediment at 16.7% (v/v) or bacterial pure cultures at 8.3% (v/v). Cysteine or tryptophan at 6 mM or salivary supernatant at 33.3% (v/v) was added. When included, zinc as ZnCl(2) was added at 6 mM. All incubations were carried out for 24 h at 37 °C. Odor generation was assessed organoleptically (0-4 severity scale); VSC was determined with a Halimeter (Interscan Corp., Chatsworth, CA) and I/S was determined using Kovac's colorimetric method. Organoleptic odor levels produced by salivary sediment mixed bacteria with the three substrates tested were comparable, though tryptophan and cysteine generated distinct and characteristic odors. With cysteine and supernatant, rapid and substantial VSC was generated; with tryptophan no such VSC formation was observed. Zinc inhibited VSC generation from cysteine and from salivary supernatant but had no effect on I/S from tryptophan. Surprisingly though, zinc which had no effect on I/S production from free tryptophan, reduced I/S production from supernatant. Of the 12 Gram negative bacteria, 75% produced I/S (mean 3.1 ± 1.5 SEM mg ml(-1)); most was generated by Porphyromonas intermedia, Porphyromonas gingivalis and Fusobacterium nucleatum. Gram positive pure cultures produced none. Comparable levels of organoleptic odor were produced by Porphyromonas gingivalis from tryptophan and cysteine. Malodor produced orally is complex because multiple microbial types, substrates, metabolic pathways and hence end products are involved. Zinc clearly inhibited I/S production in salivary supernatant, possibly by interfering with the release of tryptophan from peptides/proteins.

20.
J Breath Res ; 2(1): 017018, 2008 Mar.
Article in English | MEDLINE | ID: mdl-21386162

ABSTRACT

Bacterial degradation of the sulfur-containing amino acid, cysteine, involves two biochemical processes that contribute significantly to oral malodor generation. The first is production of hydrogen sulfide, a major component and common indicator of oral malodor formation. The second is generation of the sulfhydryl anion, HS(-), an anion that is central to the lowering of the oxidation-reduction potential (E(h)). A reduced E(h) is fundamental to the growth and metabolism of the oral Gram negative anaerobic bacteria. These microorganisms are responsible for oral putrefaction, a process primary to both oral malodor generation and gingivitis-periodontitis development. One purpose of this paper is to report on the testing of a number of anti-malodor treatments and products for their effects on H(2)S formation and E(h) reduction, two processes that occur rapidly and do so simultaneously after the oral bacteria are challenged with cysteine. A second is to report on aspects of cysteine challenge testing in the development of an anti-malodor product composed of ZnCl(2) and sodium chlorite that simultaneously inhibits both H(2)S formation and E(h) reduction and effectively inhibits oral malodor.

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