Macrophage RAGE activation is proinflammatory in NASH

Intrahepatic macrophages in nonalcoholic steatohepatitis (NASH) are heterogenous and include proinflammatory recruited monocyte-derived macrophages. The receptor for advanced glycation endproducts (RAGE) is expressed on macrophages and can be activated by damage associated molecular patterns (DAMPs) upregulated in NASH, yet the role of macrophage-specific RAGE signaling in NASH is unclear. Therefore, we hypothesized that RAGE-expressing macrophages are proinflammatory and mediate liver inflammation in NASH. Compared with healthy controls, RAGE expression was increased in liver biopsies from patients with NASH. In a high-fat, -fructose, and -cholesterol-induced (FFC)-induced murine model of NASH, RAGE expression was increased, specifically on recruited macrophages. FFC mice that received a pharmacological inhibitor of RAGE (TTP488), and myeloid-specific RAGE KO mice (RAGE-MKO) had attenuated liver injury associated with a reduced accumulation of RAGE+ recruited macrophages. Transcriptomics analysis suggested that pathways of macrophage and T cell activation were upregulated by FFC diet, inhibited by TTP488 treatment, and reduced in RAGE-MKO mice. Correspondingly, the secretome of ligand-stimulated BM-derived macrophages from RAGE-MKO mice had an attenuated capacity to activate CD8+ T cells. Our data implicate RAGE as what we propose to be a novel and potentially targetable mediator of the proinflammatory signaling of recruited macrophages in NASH.

Extracellular Vesicles in Hepatobiliary Health and Disease

Extracellular vesicles (EVs) are membrane-bound nanoparticles released by cells and are an important means of intercellular communication in physiological and pathological states. We provide an overview of recent advances in the understanding of EV biogenesis, cargo selection, recipient cell effects, and key considerations in isolation and characterization techniques. Studies on the physiological role of EVs have relied on cell-based model systems due to technical limitations of studying endogenous nanoparticles in vivo . Several recent studies have elucidated the mechanistic role of EVs in liver diseases, including nonalcoholic fatty liver disease, viral hepatitis, cholestatic liver disease, alcohol-associated liver disease, acute liver injury, and liver cancers. Employing disease models and human samples, the biogenesis of lipotoxic EVs downstream of endoplasmic reticulum stress and microvesicles via intracellular activation stress signaling are discussed in detail. The diverse cargoes of EVs including proteins, lipids, and nucleic acids can be enriched in a disease-specific manner. By carrying diverse cargo, EVs can directly confer pathogenic potential, for example, recruitment and activation of monocyte-derived macrophages in NASH and tumorigenicity and chemoresistance in hepatocellular carcinoma. We discuss the pathogenic role of EVs cargoes and the signaling pathways activated by EVs in recipient cells. We review the literature that EVs can serve as biomarkers in hepatobiliary diseases. Further, we describe novel approaches to engineer EVs to deliver regulatory signals to specific cell types, and thus use them as therapeutic shuttles in liver diseases. Lastly, we identify key lacunae and future directions in this promising field of discovery and development. © 2023 American Physiological Society. Compr Physiol 13:4631-4658, 2023.

Assessment of Lipotoxic Endoplasmic Reticulum (ER) Stress in Nonalcoholic Steatohepatitis (NASH)

Hepatocyte lipotoxicity is a hallmark of nonalcoholic steatohepatitis (NASH), and lipid induced liver injury occurs, in part, via activation of endoplasmic reticulum (ER) stress. Consequently, the unfolded protein response (UPR) is initiated, driven by three key ER transmembrane proteins, resulting in downstream responses that are dynamic and interconnected. Thus, careful interrogation of these pathways is required to investigate the complex role of ER stress in NASH. Herein, we describe different mechanisms of, and in vitro assays for assessment of lipotoxic ER stress in mouse hepatocytes.

Circulating extracellular vesicles are a biomarker for NAFLD resolution and response to weight loss surgery

There is increasing interest in the development of minimally invasive biomarkers for the diagnosis and prognosis of NAFLD via extracellular vesicles (EV). Plasma EVs were isolated by differential ultracentrifugation and quantified by nanoparticle tracking analysis from pre (n = 28) and post (n = 28) weight loss patients. In the pre weight loss group 22 had NAFLD. Nanoplasmon enhanced scattering (nPES) of gold nanoparticles conjugated to hepatocyte-specific antibodies was employed to identify hepatocyte-specific EVs. Complex lipid panel and targeted sphingolipids were performed. Logistic regression analysis was used to identify predictors of NAFLD. Plasma levels of EVs and hepatocyte-derived EVs are dynamic and decrease following NAFLD resolution due to weight loss surgery. Hepatocyte-derived EVs correlate with steatosis in NAFLD patients and steatosis and inflammation in NASH patients. Plasma levels of small EVs correlate with EV sphingolipids in patients with NASH. Hepatocyte-derived EVs measured by the nPES assay could serve as a point-of-care test for NAFLD.

Hepatic steatosis and steatohepatitis: a functional meta-analysis of sex-based differences in transcriptomic studies

Background

Previous studies have described sex-based differences in the epidemiological and clinical patterns of non-alcoholic fatty liver disease (NAFLD); however, we understand relatively little regarding the underlying molecular mechanisms. Herein, we present the first systematic review and meta-analysis of NAFLD transcriptomic studies to identify sex-based differences in the molecular mechanisms involved during the steatosis (NAFL) and steatohepatitis (NASH) stages of the disease.

Methods

Transcriptomic studies in the Gene Expression Omnibus database were systematically reviewed following the PRISMA statement guidelines. For each study, NAFL and NASH in premenopausal women and men were compared using a dual strategy: gene-set analysis and pathway activity analysis. Finally, the functional results of all studies were integrated into a meta-analysis.

Results

We reviewed a total of 114 abstracts and analyzed seven studies that included 323 eligible patients. The meta-analyses identified significantly altered molecular mechanisms between premenopausal women and men, including the overrepresentation of genes associated with DNA regulation, vinculin binding, interleukin-2 responses, negative regulation of neuronal death, and the transport of ions and cations in premenopausal women. In men, we discovered the overrepresentation of genes associated with the negative regulation of interleukin-6 and the establishment of planar polarity involved in neural tube closure.

Conclusions

Our meta-analysis of transcriptomic data provides a powerful approach to identify sex-based differences in NAFLD. We detected differences in relevant biological functions and molecular terms between premenopausal women and men. Differences in immune responsiveness between men and premenopausal women with NAFLD suggest that women possess a more immune tolerant milieu, while men display an impaired liver regenerative response.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-021-00368-1.

Development of an Automated Algorithm to Generate Guideline-based Recommendations for Follow-up Colonoscopy

BACKGROUND AND AIMS

Physician adherence to published colonoscopy surveillance guidelines varies. We aimed to develop and validate an automated clinical decision support algorithm that can extract procedure and pathology data from the electronic medical record (EMR) and generate surveillance intervals congruent with guidelines, which might increase physician adherence.

METHODS

We constructed a clinical decision support (CDS) algorithm based on guidelines from the United States Multi-Society Task Force on Colorectal Cancer. We used a randomly generated validation dataset of 300 outpatient colonoscopies performed at the Cleveland Clinic from 2012 through 2016 to evaluate the accuracy of extracting data from reports stored in the EMR using natural language processing (NLP). We compared colonoscopy follow-up recommendations from the CDS algorithm, endoscopists, and task force guidelines. Using a testing dataset of 2439 colonoscopies, we compared endoscopist recommendations with those of the algorithm.

RESULTS

Manual review of the validation dataset confirmed the NLP program accurately extracted procedure and pathology data for all cases. Recommendations made by endoscopists and the CDS algorithm were guideline-concordant in 62% and 99% of cases, respectively. Discrepant recommendations by endoscopists were earlier than recommended in 94% of the cases. In the testing dataset, 69% of endoscopist and NLP-CDS algorithm recommendations were concordant. Discrepant recommendations by endoscopists were earlier than guidelines in 91% of cases.

CONCLUSIONS

We constructed and tested an automated CDS algorithm that can use NLP-extracted data from the EMR to generate follow-up colonoscopy surveillance recommendations based on published guidelines.

Pathogenesis of Nonalcoholic Steatohepatitis: An Overview

Nonalcoholic fatty liver disease (NAFLD) is a heterogeneous group of liver diseases characterized by the accumulation of fat in the liver. The heterogeneity of NAFLD is reflected in a clinical and histologic spectrum where some patients develop isolated steatosis of the liver, termed nonalcoholic fatty liver, whereas others develop hepatocyte injury, ballooning, inflammation, and consequent fibrosis, termed nonalcoholic steatohepatitis (NASH). Systemic insulin resistance is a major driver of hepatic steatosis in NAFLD. Lipotoxicity of accumulated lipids along with activation of the innate immune system are major drivers of NASH. Lipid‐induced sublethal and lethal stress culminates in the activation of inflammatory processes, such as the release of proinflammatory extracellular vesicles and cell death. Innate and adaptive immune mechanisms involving macrophages, dendritic cells, and lymphocytes are central drivers of inflammation that recognize damage‐ and pathogen‐associated molecular patterns and contribute to the progression of the inflammatory cascade. While the activation of the innate immune system and the recruitment of proinflammatory monocytes into the liver in NASH are well known, the exact signals that lead to this remain less well defined. Further, the contribution of other immune cell types, such as neutrophils and B cells, is an area of intense research. Many host factors, such as the microbiome and gut–liver axis, modify individual susceptibility to NASH. In this review, we discuss lipotoxicity, inflammation, and the contribution of interorgan crosstalk in NASH pathogenesis.

The time required to diagnose and treat lung cancer in Delhi, India: an updated experience of a public referral center

Background

Delays that postpone the evaluation and management of malignancy may lead to considerable morbidity. The primary objective of this study was to assess the time required to diagnose and treat lung cancer at an Indian public referral center that predominantly serves lower-income patients.

Methods

A review of patients diagnosed with lung cancer between January 2008 and December 2016 was completed. We computed the median time intervals and inter-quartile ranges between symptom onset, definitive diagnostic investigation, confirmed histologic diagnosis, and chemotherapy initiation. Median intervals were correlated with baseline demographics and disease characteristics using Kruskal-Wallis test.

Results

One thousand, three hundred and-seventy patients were selected. A majority (94.5%) with non-small cell lung cancer were diagnosed with advanced disease. After developing symptoms, patients required 101 [56–168] days to undergo a definitive diagnostic study, 107 [60–173] days to confirm a diagnosis, and 126 [85–196.8] days to initiate treatment. Patients who were previously treated for tuberculosis required more time to receive chemotherapy compared to those who were not (187 [134–261.5] days vs. 113 [75–180] days, p < 0.0001). A specialty Lung Cancer Clinic was implemented in 2012, and the mean referrals per month increased nearly four-fold (p < 0.0001), but the time required to administer treatment was not shortened.

Conclusion

Among lower-income Indian patients, the most prominent delays occur prior to diagnosis. Efforts should be directed toward encouraging physicians to maintain a high index of clinical suspicion and educating patients to report concerning symptoms as early as possible.

Aging, Obesity, and the Incidence of Diverticulitis: A Population-Based Study

OBJECTIVE

To understand why the population-based incidence of diverticulitis has increased over time, we studied temporal changes in age, body mass index (BMI), and diverticulitis in Olmsted County, Minnesota.

PARTICIPANTS AND METHODS

We compared the BMIs of 2967 patients with diverticulitis and 9795 people without diverticulitis from January 1, 1980, through December 31, 2007. Because BMI is a surrogate for adipose tissue, computed tomographic estimations of abdominal fat content were compared between 381 diverticulitis cases and 381 age- and sex-matched controls.

RESULTS

Between 1980 and 2007, the prevalence of obesity increased from 12% to 49% in the population and from 19% to 40% in patients with diverticulitis (P<.001 for both). Temporal trends in age, BMI, and the increased incidence of diverticulitis in people with normal BMI accounted for 48%, 47%, and 20%, respectively, of corresponding trends in diverticulitis. The secular decline in the proportion of people with normal BMI was partly offset by an increased incidence of diverticulitis in such people. In the case-control study, BMI was greater in cases than in controls (P=.001). However, after incorporating abdominal visceral (odds ratio [OR], 2.4; 95% CI, 1.6-3.7) and subcutaneous (OR, 2.9; 95% CI, 1.7-5.2) fat content (both associated with diverticulitis), BMI was associated with lower risk (OR, 0.8; 95% CI, 0.7-0.8) of diverticulitis.

CONCLUSION

Aging, increasing obesity, and the increased incidence of diverticulitis in people with normal BMI account for the temporal increase in diverticulitis. Rather than BMI per se, increased abdominal visceral and subcutaneous fat are independently associated with diverticulitis. The incidence of diverticulitis, which is among the most common gastrointestinal diagnoses in hospitalized patients, has increased markedly since 2000. This study suggests that aging, increasing obesity, and the increased incidence of diverticulitis in people with normal BMI account for the temporal increase in diverticulitis.

Reproducibility of assessing fecal microbiota in chronic constipation

BACKGROUND

While limited data suggest that the fecal microbiota in healthy people is stable over time, the intraindividual variability of the fecal microbiota in constipated patients is unknown.

METHODS

This study evaluated the intraindividual reproducibility of fecal microbiota analyzed with 16S rRNA gene sequencing in two stool samples collected without and after a laxative, respectively, in 25 healthy people and 25 constipated women. Participants completed a food record for 3 d before the stool collection. Colonic transit was measured with scintigraphy.

KEY RESULTS

The constipated patients were older (48±15 vs 39±10 y, P=.02) than healthy participants but had a similar BMI. The total daily caloric intake was less (P=.005) in constipated (1265±350 kcal) than healthy participants (1597±402 kcal). Fourteen patients but only two controls (P<.005), had delayed colonic transit. For most measures of alpha (eg, Observed OTU number, Shannon index) and beta diversity (eg, Bray-Curtis dissimilarity, UniFrac, phyla level abundance), the ICCs between two stool samples were high, indicating moderate or strong agreement, and similar in healthy people and constipated patients. The ICC for the weighted UniFrac distance, which is weighted by abundance, was lower than its unweighted counterpart, indicating that the unweighted measure is more robust and reproducible.

CONCLUSIONS AND INFERENCES

The intraindividual reproducibility of fecal microbiota in constipated patients is high and comparable to healthy participants. For most purposes, evaluating the fecal microbiota in a single stool sample should generally suffice in adequately powered studies of healthy and constipated patients.

Assessing the colonic microbiome, hydrogenogenic and hydrogenotrophic genes, transit and breath methane in constipation

BACKGROUND

Differences in the gut microbiota and breath methane production have been observed in chronic constipation, but the relationship between colonic microbiota, transit, and breath tests remains unclear.

METHODS

In 25 healthy and 25 constipated females we evaluated the sigmoid colonic mucosal and fecal microbiota using 16S rRNA gene sequencing, abundance of hydrogenogenic FeFe (FeFe-hydA) and hydrogenotrophic (methyl coenzyme M reductase A [mrcA] and dissimilatory sulfite reductase A [dsrA]) genes with real-time qPCR assays, breath hydrogen and methane levels after oral lactulose, and colonic transit with scintigraphy.

KEY RESULTS

Breath hydrogen and methane were not correlated with constipation, slow colon transit, or with abundance of corresponding genes. After adjusting for colonic transit, the abundance of FeFehydA, dsrA, and mcrA were greater (P<.005) in colonic mucosa, but not stool, of constipated patients. The abundance of the selected functional gene targets also correlated with that of selected taxa. The colonic mucosal abundance of FeFe-hydA, but not mcrA, correlated positively (P<.05) with breath methane production, slow colonic transit, and overall microbiome composition. In the colonic mucosa and feces, the abundance of hydrogenogenic and hydrogenotrophic genes were positively correlated (P<.05). Breath methane production was not associated with constipation or colonic transit.

CONCLUSIONS & INFERENCES

Corroborating our earlier findings with 16S rRNA genes, colonic mucosal but not fecal hydrogenogenic and hydrogenotrophic genes were more abundant in constipated vs. healthy subjects independent of colonic transit. Breath gases do not directly reflect the abundance of target genes contributing to their production.

High-resolution Anorectal Manometry for Identifying Defecatory Disorders and Rectal Structural Abnormalities in Women

BACKGROUND & AIMS

Contrary to conventional wisdom, the rectoanal gradient during evacuation is negative in many healthy people, undermining the utility of anorectal high-resolution manometry (HRM) for diagnosing defecatory disorders. We aimed to compare HRM and magnetic resonance imaging (MRI) for assessing rectal evacuation and structural abnormalities.

METHODS

We performed a retrospective analysis of 118 patients (all female; 51 with constipation, 48 with fecal incontinence, and 19 with rectal prolapse; age, 53 ± 1 years) assessed by HRM, the rectal balloon expulsion test (BET), and MRI at Mayo Clinic, Rochester, Minnesota, from February 2011 through March 2013. Thirty healthy asymptomatic women (age, 37 ± 2 years) served as controls. We used principal components analysis of HRM variables to identify rectoanal pressure patterns associated with rectal prolapse and phenotypes of patients with prolapse.

RESULTS

Compared with patients with normal findings from the rectal BET, patients with an abnormal BET had lower median rectal pressure (36 vs 22 mm Hg, P = .002), a more negative median rectoanal gradient (-6 vs -29 mm Hg, P = .006) during evacuation, and a lower proportion of evacuation on the basis of MRI analysis (median of 40% vs 80%, P < .0001). A score derived from rectal pressure and anorectal descent during evacuation and a patulous anal canal was associated (P = .005) with large rectoceles (3 cm or larger). A principal component (PC) logistic model discriminated between patients with and without prolapse with 96% accuracy. Among patients with prolapse, there were 2 phenotypes, which were characterized by high (PC1) or low (PC2) anal pressures at rest and squeeze along with higher rectal and anal pressures (PC1) or a higher rectoanal gradient during evacuation (PC2).

CONCLUSIONS

In a retrospective analysis of patients assessed by HRM, measurements of rectal evacuation by anorectal HRM, BET, and MRI were correlated. HRM alone and together with anorectal descent during evacuation may identify rectal prolapse and large rectoceles, respectively, and also identify unique phenotypes of rectal prolapse.

Relationship Between Gastric Emptying and Diurnal Glycemic Control in Type 1 Diabetes Mellitus: A Randomized Trial

CONTEXT

In type 1 diabetes (T1D), delayed gastric emptying (GE) may predispose to a mismatch between insulin delivery and glucose absorption. Previous studies evaluated, only partly, the relationship between delayed GE and postprandial, but not diurnal, glycemia.

OBJECTIVE

To assess the relationship between GE disturbances and glycemic control in T1D and the effects of accelerating GE on glycemic control.

DESIGN, SETTING, AND PARTICIPANTS

This was a randomized placebo-controlled trial in 30 patients with T1D on an insulin pump at an academic medical center.

INTERVENTION(S)

GE was evaluated with a [13C]-Spirulina breath test at baseline (GEbaseline), during intravenous saline or erythromycin (2 or 3 mg/kg; GEiv), and after 7 days of oral erythromycin or placebo (GEoral). Weighed meals were provided throughout the study.

MAIN OUTCOME MEASURE(S)

These were GE and continuous glucose monitoring (CGM).

RESULTS

The baseline glycosylated hemoglobin was 7.6% ± 0.8% (60 ± 8.7 mmol/mol); 12 patients (40%) had delayed GE; faster GE was associated with a greater postprandial CGM-based glucose, but slower GE was not associated with postprandial hypoglycemia (<70 mg/dL). Intravenous (3 mg/kg) but not oral erythromycin accelerated GE. The relationship between GE and glycemia differed between the postprandial periods and the entire day. After adjusting for carbohydrate intake and insulin consumption, faster GE was associated with more hyperglycemia during the postprandial period but lower glucose values across the entire study.

CONCLUSIONS

In T1D, pharmacologically mediated acceleration of GE increases postprandial CGM-based glucose. In contrast, delayed GE is associated with greater CGM-based glucose values over the entire day.

Determinants and clinical impact of pressure drift in manoscan anorectal high resolution manometry system

BACKGROUND

Pressure drift (PD), resulting from differences between room and body temperature, reduces the accuracy of pressure measurements with the Manoscan high resolution manometry (HRM) system. Our aims were to assess PD during anorectal HRM.

METHODS

Defined as the residual pressure measured immediately after the catheter was removed, PD was calculated for each sensor and averaged across all 12 sensors in 454 anorectal consecutive studies recorded with 3 HRM catheters. The relationship between PD and study duration, number of prior uses of a catheter, and peak and average pressure exposure during a study were evaluated. The correction of PD with a software algorithm (thermal compensation) was evaluated in 76 studies where the most distal sensor was outside the body.

KEY RESULTS

The PD varied among sensors and across catheters. The average PD (7.3 ± 0.2 mmHg) was significantly greater for newer catheters, during longer studies, or when sensors were exposed to higher pressures. Together, these factors explained 81% of the variance in overall PD. After thermal compensation, the uncorrected median PD for the most distal sensor was 2.5-5 mmHg over the study duration. Correcting this changed the interpretation (e.g., as abnormal instead of normal) of at least 1 anorectal parameter in eight of 76 studies.

CONCLUSIONS & INFERENCES

During anorectal HRM, PD declines with catheter use and is greater for newer catheters, when sensors are exposed to higher pressures, and for studies of longer duration. While PD is partially corrected with thermal compensation algorithms, the impact on interpretation is modest.

Evaluating the safety and the effects on colonic compliance of neostigmine during motility testing in patients with chronic constipation

BACKGROUND

Neostigmine, an acetyl cholinesterase inhibitor, stimulates colonic motor activity and may induce vagally mediated cardiovascular effects. Our aim was to evaluate effects of i.v. neostigmine on colonic compliance and its safety in patients with chronic constipation.

METHODS

We retrospectively reviewed medical records of a selected group of 144 outpatients with chronic constipation who were refractory to treatment. These patients had undergone intracolonic motility and compliance measurements with an infinitely compliant balloon linked to a barostat. Data abstracted included barostat balloon mean volumes with increases in pressure (4 mmHg steps from 0 to 44 mmHg) before and after i.v. neostigmine. Vital signs and oxygen saturation before and after neostigmine were recorded.

KEY RESULTS

Of the 144 patients, 133 were female, mean age was 41.0 ± 15.4 years (SD), and duration of constipation was 12.9 ± 13.8 years. Among patients who had undergone colonic transit measurement by scintigraphy, the overall colonic transit at 24 h (geometric center, GC24 [n = 115]) was 1.5 ± 0.7 (normal >1.3), and at 48 h (GC48 [n = 75]) it was 2.3 ± 0.9 (normal >1.9). Neostigmine decreased colonic compliance at lower distension pressures (e.g., 12 and 20 mmHg [both p < 0.001]), but not at 40 mmHg. There were expected minor changes in vital signs in response to neostigmine in 144 patients; however, one patient developed unresponsiveness, significant bradycardia, hypotension, and muscular rigidity that responded to 400 mcg i.v. atropine.

CONCLUSIONS & INFERENCES

Neostigmine significantly decreases colonic compliance in patients with refractory chronic constipation. Symptomatic bradycardia in response to neostigmine should be promptly reversed with atropine.

Diaphragmatic breathing for rumination syndrome: efficacy and mechanisms of action

BACKGROUND

While high resolution esophageal manometry combined with impedancometry has demonstrated that gastric pressurizations lead to rumination, the contribution of upper esophageal sphincter (UES) and esophagogastric junction (EGJ) function to rumination is unclear. Behavioral therapy with diaphragmatic breathing (DB) can reduce rumination. We aimed to evaluate the pressures in the stomach, EGJ and UES during rumination and the effects of DB augmented with biofeedback therapy.

METHODS

Sixteen patients with rumination were studied with manometry and impedancometry before and after a meal. The postprandial assessment comprised three periods: before, during, and after DB augmented with biofeedback therapy.

KEY RESULTS

All patients had postprandial rumination, which was associated (p < 0.001) with increased gastric pressure and reversal of the postprandial gastroesophageal pressure gradient from -4 (-43 to 18) before to 20 (7-79) mmHg during rumination. The EGJ pressure was lower (p < 0.001) during gastric pressurizations that were associated with rumination vs those that were not. The UES also relaxed, almost completely, during rumination. Patients had a median (range) of 5 (2-10) rumination episodes before, 1 (0-2) (p < 0.001) during, and 3 (1-5) after (p < 0.001 vs during) diaphragmatic breathing. During manometry and impedancometry, DB was well-tolerated and learned within 5 min. Diaphragmatic breathing increased EGJ pressure (p < 0.001) and restored a negative gastroesophageal pressure gradient (-20 mmHg [-80 to 7]).

CONCLUSIONS & INFERENCES

Diaphragmatic breathing aided with high resolution esophageal manometry is well-tolerated, effective and averts the gastroesophageal pressure disturbance that leads to rumination.

Relationship Between Microbiota of the Colonic Mucosa vs Feces and Symptoms, Colonic Transit, and Methane Production in Female Patients With Chronic Constipation

BACKGROUND & AIMS

In fecal samples from patients with chronic constipation, the microbiota differs from that of healthy subjects. However, the profiles of fecal microbiota only partially replicate those of the mucosal microbiota. It is not clear whether these differences are caused by variations in diet or colonic transit, or are associated with methane production (measured by breath tests). We compared the colonic mucosal and fecal microbiota in patients with chronic constipation and in healthy subjects to investigate the relationships between microbiota and other parameters.

METHODS

Sigmoid colonic mucosal and fecal microbiota samples were collected from 25 healthy women (controls) and 25 women with chronic constipation and evaluated by 16S ribosomal RNA gene sequencing (average, 49,186 reads/sample). We assessed associations between microbiota (overall composition and operational taxonomic units) and demographic variables, diet, constipation status, colonic transit, and methane production (measured in breath samples after oral lactulose intake).

RESULTS

Fourteen patients with chronic constipation had slow colonic transit. The profile of the colonic mucosal microbiota differed between constipated patients and controls (P < .05). The overall composition of the colonic mucosal microbiota was associated with constipation, independent of colonic transit (P < .05), and discriminated between patients with constipation and controls with 94% accuracy. Genera from Bacteroidetes were more abundant in the colonic mucosal microbiota of patients with constipation. The profile of the fecal microbiota was associated with colonic transit before adjusting for constipation, age, body mass index, and diet; genera from Firmicutes (Faecalibacterium, Lactococcus, and Roseburia) correlated with faster colonic transit. Methane production was associated with the composition of the fecal microbiota, but not with constipation or colonic transit.

CONCLUSIONS

After adjusting for diet and colonic transit, the profile of the microbiota in the colonic mucosa could discriminate patients with constipation from healthy individuals. The profile of the fecal microbiota was associated with colonic transit and methane production (measured in breath), but not constipation.

Effect of neostigmine on gastroduodenal motility in patients with suspected gastrointestinal motility disorders

BACKGROUND

Acetylcholinesterase inhibitors (ACIs), e.g., neostigmine, are known to increase upper and lower gastrointestinal (GI) motility and are used to treat acute colonic pseudoobstruction. However, their effects on gastroduodenal motility in humans are poorly understood. Our hypotheses were that, in patients with suspected GI motility disorders, neostigmine increases gastric and small intestinal motor activity, and these effects are greater in patients with cardiovagal neuropathy, reflecting denervation sensitivity.

METHODS

In this open label study, the effects of neostigmine (1 mg intravenously) on gastroduodenal motor activity recorded with manometry were assessed in 28 patients with a suspected GI motility disorder. Cardiovagal function was assessed with the heart rate response to deep breathing and GI transit by scintigraphy.

KEY RESULTS

The final diagnoses were gastroparesis (6 patients), gastroparesis with intestinal neuropathy (3 patients), intestinal neuropathy or pseudoobstruction (5 patients), functional dyspepsia (6 patients), chronic abdominal pain (3 patients), mechanical small intestinal obstruction (3 patients), and pelvic floor dysfunction (2 patients). Neostigmine increased both antral and intestinal phasic pressure activity (p < 0.001). Neostigmine increased antral and intestinal pressure activity in 81% and 50% of patients with reduced postprandial antral and intestinal contractile responses to meal, respectively. The antroduodenal pressure response to neostigmine was not higher in patients with cardiovagal dysfunction.

CONCLUSIONS & INFERENCES

Neostigmine increased antral and intestinal motor activity in patients with hypomotility, including intestinal dysmotility. These responses to neostigmine were not greater in patients with cardiovagal dysfunction. The use of longer-acting ACIs for treating antroduodenal dysmotility warrant further study.

Isolation of Mycobacterium tuberculosis from sputum of tribal, non-tribal pulmonary tuberculosis patients of Andaman & Nicobar islands by conventional culture method and assessment of first line anti-tuberculosis drug susceptibility patterns

BACKGROUND

Drug resistance surveys have not yet conducted in these Islands and as such no data exists on drug resistance currently.

AIMS

the present study was initiated with the objective of isolation and assessment of Drug resistance patterns of Mycobacterium tuberculosis isolates from sputum specimens collected from different categories of Tribal, Non-Tribal pulmonary tuberculosis patients treated under DOTS and Non-DOTS program by conventional culture and Proportion sensitivity (PST) method to detect patients with Multidrug resistant strains.

METHODS

The investigation was hospital based laboratory surveillance study carried out for a period of 3 years at the selected hospitals of Andaman district (TB ward GB Pant Hospital at Port Blair, CHC Bamboflat at Port Blair and CHC Rangat at Rangat) and Nicobar district (CHC Nancowry at Nancowry groups of Islands), among the new cases and re-treatment cases of tuberculosis patient under DOTS program and Non-DOTS patients attended selected hospitals of Andaman & Nicobar districts chosen for the study.

RESULTS

83 culture positive isolates obtained (74 identified as M. tuberculosis) from the sputum specimen of 162 cases of tuberculosis patient by conventional culture method. 60 M. tuberculosis isolates subjected to drug susceptibility test using PST method, 7 patients (11.67%) found to be Multidrug resistant tuberculosis (MDR-TB), resistant patterns were S + H + R + E = 1(Cat II-DOTS),H + r = 3(Cat-I DOTS = 1, Cat II-DOTS-1,Non-DOTS = 1), Rifampicin resistant alone = 2 (Non-DOTS = 1, Cat II-DOTS = 1) and R + E = 1(Cat I-DOTS).

CONCLUSIONS

Laboratory finding suggested that nine MDR-TB strains detected in DOTS and Non-DOTS among 60 M. tuberculosis isolates were selected for drug susceptibility testing but two isolates detected as MDR-TB from patients was already on Second line drugs treatment were not included in the MDR-TB detection criteria. Hence 7 patients (11.67%) declared to be Multidrug resistant tuberculosis (MDR-TB). 2 MDR-TB strains with resistant patterns H + r = 1(Cat II-DOTS), Rifampicin resistant alone = 1(Non-DOTS) detected from 12 isolates of Tribal patients from Nicobar district and 5 MDR-TB strains with resistant patterns S + H + R + E = 1 (Cat II-DOTS), H + r = 2(Cat I-DOTS = 1,Non-DOTS = 1), Rifampicin resistant alone = 1 (Cat II-DOTS) and R + E = 1(Cat I-DOTS) detected from 48 isolates of Non-Tribal patients from Andaman district. To assess the MDR-TB burden in the islands, systematic drug resistant surveillance study needs to be conducted.

Acute corrosive injuries of the stomach: a single unit experience of thirty years

Introduction. The spectrum of gastric injury due to corrosives can vary. This paper presents a single center experience of over 30 years of corrosive gastric injuries of 39 patients with acute gastric injuries from 1977 till 2006. Patients and Methods. Two thirds of the patients in the acute injury group had a concomitant esophageal injury. The age of the patients ranged from 4 years to 65 years with a slight preponderance of males. (M : F ratio 22 : 17). Results. 36 out of 39 acute gastric injuries were due to ingestion of acids. Three patients had history of caustic soda ingestion. Oral hyperemia or ulcers of varying extent were seen in all patients. The stomach showed hyperemia in 10, extensive ulcers in 13, and mucosal necrosis in 10 patients. Fifteen patients (15/39, 38.5%) were managed conservatively. Twenty four patients (24/39, 61.5%) underwent laparotomy: one for frank peritonitis, 10 for gastric mucosal necrosis, and 13 others for extensive gastric ulcerations. Overall the mortality rate was 29.6 %. Conclusion. Although the mortality and morbidity of acute corrosive gastric injuries is high, the key to improve the survival is early identification of perforation, maintenance of nutrition and control of sepsis.

Chronic corrosive injuries of the stomach-a single unit experience of 109 patients over thirty years

BACKGROUND

Corrosive gastric injuries are not uncommon in developing countries because acids, which are more frequently associated with gastric injury, constitute the major type of offending chemical. The spectrum of gastric injury may vary from acute to varying types of chronic gastric involvement.

METHODS

The 109 consecutive patients with chronic corrosive gastric injuries treated in a single tertiary care superspecialty institute over a period of 30 years were reviewed with special reference to presentation and problems in management.

RESULTS

Acids contributed to 82.6% of chronic injuries. Chronic gastric injuries were usually one of five types in these patients. The majority had prepyloric strictures (83.5%). The remaining strictures were antral (4.6%), body (3.7%), pyloroduodenal (2.7%), or diffuse (5.5%).Twenty-one (22.8%) patients had a delayed gastric outlet obstruction, and18 patients had a concomitant esophageal stricture requiring a bypass. Most of the patients with chronic injury underwent surgical correction with Billroth I gastrectomy (77.1%), loop gastrojejunostomy (11.0%), and distal gastrectomy with Polya reconstruction (3.7%). Other procedures performed were pyloroplasty in 1 patient and colonic conduit jejunal anastomosis in 6 patients. One patient (1%) died in the postoperative period.

CONCLUSIONS

The management of chronic corrosive gastric injury depends on the type of gastric involvement, the presence of co-existent esophageal stricture, and the general condition of the patient. A limited resection of the affected stomach is the ideal procedure for the common type of gastric injury. In patients whose general condition prohibits major resection or where the stricture extends to the antrum the best treatment is a loop gastroenterostomy. Type III, IV, V strictures require individualized treatment. Delayed gastric outlet obstruction affects the treatment plan of combined gastric and esophageal injuries.

Recombinant interleukin-4 enhances Campylobacter jejuni invasion of intestinal pig epithelial cells (IPEC-1)

Campylobacter jejuni, a leading cause of bacterial gastroenteritis, has a diverse spectrum of disease expression. Polymicrobial infections may contribute to this, such as Trichuris, which elicits type 2 cytokines (including IL-4) and downregulates type 1 immunity. In previous studies, gnotobiotic piglets infected with C. jejuni and Trichuris suis had bloody diarrhea and marked gastrointestinal pathology, including bacterial invasion into epithelial cells and macrophages. Neonatal swine given these dual infections had elevated IL-4 and IL-10 responses in feces. In the studies reported here, we hypothesized that IL-4 or IL-10 enhances invasion of intestinal pig epithelial cells (IPEC-1) by C. jejuni. 10-14-day-old IPEC-1 cells were pretreated with recombinant IL-4 (rIL-4) or rIL-10 for 5h and then challenged with C. jejuni. Cells pretreated with rIL-4 were viable and showed approximately 6-fold increases in C. jejuni (but not Escherichia coli DH5alpha) internalization compared to cells with no pretreatment. Enhanced C. jejuni invasion was rIL-4 dose-dependent and reversed by addition of anti-IL-4 antibody. Preincubation with rIL-10 did not significantly alter C. jejuni internalization. Transepithelial electrical resistance (TEER) was significantly reduced following rIL-4 treatment, but not rIL-10 treatment. After rIL-4 pretreatment and C. jejuni challenge, light microscopy showed vacuolated cells with damaged paracellular junctions. Transmission electron microscopy (TEM) showed multiple internalized bacteria. Most were in the cytoplasm, but some were within or adjacent to vacuoles. We conclude that rIL-4 damages paracellular junctions and alters the physiology of these epithelial cells allowing increased invasion of C. jejuni.

Assessment of vagotomy status with postprandial urinary alkaline tide

AIM

This study was carried out to assess whether the postprandial urinary alkaline tide, as a marker for the completeness of vagotomy, is dependent on the nature of the test meal, whether it is affected by proton pump inhibitor therapy, and whether it is reliable.

METHODS

The postprandial urinary alkaline tide (PUAT) pattern was prospectively assessed in three different study groups and one control group of healthy volunteers. The three study groups were as follows; A (n = 20) i.e. the Proton Pump Inhibitor (PPI) Group; B (n = 25) i.e. the Truncal Vagotomy (TV) Group; and C (n = 5) i.e. the Recurrent Ulcer (RU) Group. Urinary pH was measured by a pocket digital pH meter.

RESULTS

Postprandial urinary alkaline tide in the control group was significantly higher compared to the fasting levels. Liquid diet did not elicit a significant urinary alkaline tide response. There was a statistically significant fall in both fasting urinary pH (5.34 +/- 0.70 vs. 4.80 +/- 0.61, p = 0.031) and the postprandial alkaline tide (6.99 +/- 0.79 vs. 4.94 +/- 0.63, p = 0.0001) after taking proton pump inhibitors. In the truncal vagotomy and gastrojejunostomy group it was found that there was a significant fall in both the mean fasting (5.28 +/- 0.58, vs. 4.92 +/- 0.66, p = 0.032) and the postprandial urinary pH (6.29 +/- 0.92 vs. 5.09 +/- 0.73, p = 0.0001) following surgery.

CONCLUSION

This study establishes that simple measurement of the urinary pH before and after a standard test meal can be used as an accurate routine test for the completion of vagotomy. It also showed that proton pump inhibitors abolish the alkaline tide and therefore must be discontinued before measuring the alkaline tide. Liquid test meal was not effective in eliciting an alkaline tide as compared to a solid meal.

Sternocleidomastoid muscle myocutaneous flap for corrosive pharyngoesophageal strictures

BACKGROUND

Strictures at the pharyngoesophageal junction represent a subgroup of corrosive esophageal strictures requiring a specialized management approach. Non-dilatable cricopharyngeal strictures need surgical intervention. We report the use of the sternocleidomastoid muscle myocutaneous inlay flap (SCMMIF) for reconstruction of the cervical esophagus in patients with corrosive strictures.

METHODS

A SCMMIF was used in four patients with cricopharyngeal strictures. The surgical technique is described. All patients had complete dilatation of the stenosed cricopharyngeal segment as seen on postoperative endoscopy and contrast studies. One patient was managed successfully for a short midesophageal stricture by serial endoscopic dilatations. Another patient underwent an esophagocoloplasty subsequently for bypass of the long distal esophageal stricture The last two patients await esophagocoloplasty.

CONCLUSIONS

This is the first report on the use of sternocleidomastoid muscle myocutaneous inlay flap for corrosive cricopharyngeal strictures. The flap is simple to construct, is effective and can be performed in a short time, and yields good cosmetic results.

Serum pepsinogen I and II levels in various gastric disorders with special reference to their use as a screening test for carcinoma stomach

INTRODUCTION

The role of serum pepsinogen in the diagnosis of gastric carcinoma is well established. Its role in other common upper alimentary disorders has not been widely studied. The aim of this study was to describe the effect of various gastric disorders on the levels of pepsinogen I, pepsinogen II and pepsinogen I/II ratio, with an emphasis on the diagnosis of carcinoma stomach in the South Indian population.

METHODS

A total of 210 patients in seven groups, including one control group, were studied. The groups included patients with carcinoma stomach, Helicobacter pylori gastritis, peptic ulcer, portal hypertensive gastropathy, non-ulcer dyspepsia and erosive gastritis. Serum pepsinogen I, pepsinogen II and pepsinogen I/II ratio were estimated using an enzyme-linked immunosorbent assay technique.

RESULTS

Patients with carcinoma of the stomach, when compared with controls, had a significantly lower pepsinogen I level (87.2 microg/L vs. 158.1 microg/L, p=0.0002) and pepsinogen I/II ratio (4.3 vs. 7.2, p = 0.0001). No significant change in pepsinogen levels occurred in the other groups. The cut-off levels of pepsinogen I (115.3 microg/L) and pepsinogen I/II ratio (6.2), determined by THE ROC curve, when applied in parallel provided a sensitivity of 97% and a negative predictive value of 91.4% for the diagnosis of carcinoma stomach. When the tests were applied in parallel, the likelihood ratio of a negative test was 0.06, indicating that individuals without carcinoma stomach were 16 times more likely to have a negative test than those with carcinoma. This fulfilled the essential prerequisites of an ideal screening test.

CONCLUSION

Serum pepsinogen estimation is a useful diagnostic tool in the diagnosis of carcinoma stomach. The significance of serum pepsinogen level in portal hypertensive gastropathy, non-ulcer dyspepsia, peptic ulcer, Helicobacter pylori gastritis and erosive gastritis was not established.

Flagella promote Escherichia coli K1 association with and invasion of human brain microvascular endothelial cells

Escherichia coli containing the K1 capsule is the leading cause of gram-negative meningitis, but the pathogenesis of this disease is not completely understood. Recent microarray experiments in which we compared the gene expression profile of E. coli K1 associated with human brain microvascular endothelial cells (HBMEC) to the gene expression profile of E. coli K1 not associated with HBMEC revealed that there was a threefold increase in the expression of the fliI gene, encoding an ATP synthase involved in flagellar synthesis and motility, in HBMEC-associated E. coli. In this study, we examined the role of flagella in E. coli K1 association with and invasion of HBMEC by constructing isogenic DeltaflhDC, DeltafliI, DeltafliC, and DeltacheW mutants that represented each class of flagellar genes. Mutations that affected the flagellum structure and flagellum formation (DeltaflhDC, DeltafliI, and DeltafliC) resulted in significant defects in motility, as well as in HBMEC association and invasion, compared to the characteristics of the wild-type strain when preparations were examined with or without centrifugation. Transcomplementation with the corresponding genes restored the levels of these mutants to the levels of the parent strain. These findings suggest that the HBMEC association and invasion defects of the mutants are most likely related to flagella and less likely due to their motility defects. This conclusion was supported by our demonstration that the cheW mutant was not motile but was able to associate with and invade HBMEC. In addition, purified recombinant flagellin reduced the association of the wild-type strain with HBMEC by approximately 40%, while it had no effect on the fliC mutant's association with HBMEC. Together, these findings indicate that flagella promote E. coli K1 binding to HBMEC.

Trichuris suis excretory secretory products (ESP) elicit interleukin-6 (IL-6) and IL-10 secretion from intestinal epithelial cells (IPEC-1)

Immune responses to gastrointestinal helminth infections have received increasing attention due to similarities to allergen-induced responses. In fact, the whipworm parasite of swine, Trichuris suis, has been used in beginning clinical trials as an antidote to inflammatory bowel disease. This strategy was based on this similarity and the recognition that other worms have been documented to induce anti-inflammatory responses in the host. In an effort to understand the basis for this response, we hypothesized that the proteins and peptides secreted by T. suis stimulate local intestinal epithelial cells to produce anti-inflammatory cytokines. To test this hypothesis in a correlate system of the natural swine host, T. suis excretory secretory products (ESP) were used to treat both differentiated and undifferentiated intestinal pig epithelial cells (IPEC-1) in vitro as a model for the effect on villus tip and crypt epithelial cells in the vicinity of the worms. IPEC-1 were exposed to low-level doses (0.3mg/ml) of T. suis ESP, and IL-4, IL-6 and IL-10 cytokine responses were measured by an enzyme-linked immunosorbant assay (ELISA). IL-6 was the predominant cytokine produced, accompanied by moderate IL-10 secretion from both differentiated and undifferentiated cells. As expected, IL-4 was not produced by IPEC-1. Additionally, IL-6 and IL-10 cytokines were produced within 24h, suggesting that these two cytokines form part of the primary host response to T. suis infections. These data suggest that T. suis ESP could enhance host immune responses and modulation through the induction of enteric IL-6 and IL-10.

A study on trend of relapse in leprosy and factors influencing relapse

A retrospective analysis of data pertaining to the rural field operation area of the Central Leprosy Teaching and Research Institute, Chengalpattu, Tamil Nadu, was carried out to determine the magnitude of relapse after MDT and its significance with other variables. The study included 3248 leprosy patients who have successfully completed treatment during 1987-2003, of whom 2892 were PB and 356 MB cases. A total of 58 cases of relapse was reported which gives a crude cumulative relapse rate of 1.78% for the 16-year period of follow-up and the rates for PB and MB were 1.9% and 0.84% respectively. With respect to PB cases, 68% of relapses were reported in the first 3 years of RFT. The person-year relapse rate was highly significant with regard to the number of skin lesions (p<0.0002) and nerve involvement (p<0.0002). The person-year relapse rate did not differ significantly between PB and MB leprosy, male and female, and child and adult cases. RFT year cohort relapse rate reveals that the introduction of MB-MDT regimen for PB leprosy had resulted in the reduction of relapses among PB cases after 1998. The relapse rate with reference to the time gap after RFT reveals that relapse declines with passage of time after RFT. The risk of relapse was very low in both PB and MB leprosy which fact emphasizes that proper counselling about signs and symptoms of relapse during RFT is adequate to combat the problem. A majority of relapses occurred in the first three years after RFT. The number of skin lesions and involvement of nerves were the main risk factors for relapse.