Disruption of intestinal barrier and endotoxemia after traumatic brain injury: Implications for post-traumatic epilepsy

OBJECTIVE

Traumatic brain injury (TBI) may lead to the disruption of the intestinal barrier (IB), and to the escape of products of commensal gut bacteria, including lipopolysaccharide (LPS), into the bloodstream. We examined whether lateral fluid percussion injury (LFPI) and post-traumatic epilepsy (PTE) are associated with the increased intestinal permeability and endotoxemia, and whether these events in turn are associated with PTE.

METHODS

LFPI was delivered to adult male Sprague-Dawley rats. Before, 1 week, and 7 months after LFPI, the IB permeability was examined by measuring plasma concentration of fluorescein isothiocyanate-labeled dextran (FD4) upon its enteral administration. Plasma LPS concentration was measured in the same animals, using enzyme-linked immunosorbent assay. PTE was examined 7 months after LFPI, with use of video-EEG (electroencephalography) monitoring.

RESULTS

One week after LFPI, the IB disruption was detected in 14 of 17 and endotoxemia - in 10 of 17 rats, with a strong positive correlation between FD4 and LPS levels, and between plasma levels of each of the analytes and the severity of neuromotor deficit. Seven months after LFPI, IB disruption was detected in 13 of 15 and endotoxemia in 8 of 15 rats, with a strong positive correlation between plasma levels of the two analytes. Five of 15 LFPI rats developed PTE. Plasma levels of both FD4 and LPS were significantly higher in animals with PTE than among the animals without PTE. The analysis of seven rats, which were examined repeatedly at 1 week and at 7 months, confirmed that late IB disruption and endotoxemia were not due to lingering of impairments occurring shortly after LFPI.

SIGNIFICANCE

LFPI leads to early and remote disruption of IB and a secondary endotoxemia. Early and late perturbations may occur in different subjects. Early changes reflect the severity of acute post-traumatic motor dysfunction, whereas late changes are associated with PTE.

Altered brain structural connectivity in patients with longstanding gut inflammation is correlated with psychological symptoms and disease duration

OBJECTIVE

We aimed to identify differences in network properties of white matter microstructure between asymptomatic ulcerative colitis (UC) participants who had a history of chronic gut inflammation, healthy controls (HCs) and a disease control group without gut inflammation (irritable bowel syndrome; IBS).

DESIGN

Diffusion weighted imaging was conducted in age and sex-matched participants with UC, IBS, and HCs (N = 74 each), together with measures of gastrointestinal and psychological symptom severity. Using streamline connectivity matrices and graph theory, we aimed to quantify group differences in brain network connectivity. Regions showing group connectivity differences were correlated with measures showing group behavioral and clinical differences.

RESULTS

UC participants exhibited greater centrality in regions of the somatosensory network and default mode network, but lower centrality in the posterior insula and globus pallidus compared to HCs (q < 0.05). Hub analyses revealed compromised hubness of the pallidus in UC and IBS compared to HCs which was replaced by increased hubness of the postcentral sulcus. Surprisingly, few differences in network matrices between UC and IBS were identified. In UC, centrality measures in the secondary somatosensory cortex were associated with depression (q < 0.03), symptom related anxiety (q < 0.04), trait anxiety (q < 0.03), and symptom duration (q < 0.05).

CONCLUSION

A history of UC is associated with neuroplastic changes in several brain networks, which are associated with symptoms of depression, trait and symptom-related anxiety, as well as symptom duration. When viewed together with the results from IBS subjects, these findings suggest that chronic gut inflammation as well as abdominal pain have a lasting impact on brain network organization, which may play a role in symptoms reported by UC patients, even when gut inflammation has subsided.

Specimen Collection and Analysis of the Duodenal Microbiome

Shifts in the microbiome have been correlated with the physiology and pathophysiology of many organ systems both in humans and in mouse models. The gut microbiome has been typically studied through fecal specimen collections. The ease of obtaining fecal samples has resulted in many studies that have revealed information concerning the distal luminal gastrointestinal tract. However, few studies have addressed the importance of the microbiome in the proximal gut. Given that the duodenum is a major site for digestion and absorption, its microbiome is relevant to nutrition and liver disease and warrants further investigation. Here we detail a novel method for sampling the proximal luminal and mucosal gut microbiome in human subjects undergoing upper endoscopy by obtaining duodenal aspirate and biopsies. Specimen procurement is facile and unaffected by artifacts such as patient preparatory adherence, as might be the case in obtaining colonic samples during colonoscopy. The preliminary results show that the luminal and mucosal microbiomes differ significantly, which is likely related to environmental conditions and barrier functions. Therefore, a combination of duodenal aspirate and biopsies reveal a more comprehensive picture of the microbiome in the duodenum. Biopsies are obtained from the descending and horizontal segments of the duodenum, which are anatomically close to the liver and biliary tree. This is important in studying the role of bile acid biology and the gut-liver axis in liver disease. Biopsies and aspirate can be used for 16S ribosomal RNA sequencing, metabolomics, and other similar applications.

Proximal colon-derived O-glycosylated mucus encapsulates and modulates the microbiota

Colon mucus segregates the intestinal microbiota from host tissues, but how it organizes to function throughout the colon is unclear. In mice, we found that colon mucus consists of two distinct O-glycosylated entities of Muc2: a major form produced by the proximal colon, which encapsulates the fecal material including the microbiota, and a minor form derived from the distal colon, which adheres to the major form. The microbiota directs its own encapsulation by inducing Muc2 production from proximal colon goblet cells. In turn, O-glycans on proximal colon-derived Muc2 modulate the structure and function of the microbiota as well as transcription in the colon mucosa. Our work shows how proximal colon control of mucin production is an important element in the regulation of host-microbiota symbiosis.

Longitudinal Characterisation of the Gastrointestinal Tract Microbiome in Systemic Sclerosis

Objectives

To evaluate changes in microbial composition and the evolution of gastrointestinal tract (GIT) symptoms in systemic sclerosis (SSc).

Methods

Adult SSc patients provided stool specimens every 3 months over the course of 1 year. Participants completed the University of California, Los Angeles (UCLA) GIT 2.0 questionnaire to assess GIT symptom severity at each stool collection. The microbiota from these samples were determined by Illumina HiSeq 2500 16S ribosomal RNA sequencing (Illumina, Inc., San Diego, California, USA). Mixed effect models evaluated changes in GIT symptoms and microbial composition over time.

Results

Among 19 patients with SSc (female; 89.5%; median age: 51.3 years), the median disease duration was 7 years and the baseline total GIT 2.0 score was 0.7 (standard deviation: 0.6). The majority of participants (63%) provided at least four stool samples over the course of the 12-month study. Patients with longer disease durations had increased GIT symptoms over the course of the study. There was no difference in the course of GIT symptoms over time between patients with limited versus diffuse cutaneous disease. The relative abundances of specific genera did not change over time within individual subjects. After controlling for age, sex, ethnicity, disease duration, and SSc subtype (i.e., limited versus diffuse), low abundance of Bacteroides was associated with increased GIT symptoms over time.

Conclusion

This study is the first to have longitudinally characterised the lower GIT microbiome in SSc patients and demonstrated relative stability of genera abundance over the course of 1 year. The findings provide additional evidence that specific genera are associated with SSc-GIT symptoms and warrant further evaluation in larger SSc studies.

Understanding the Heterogeneity of Obesity and the Relationship to the Brain-Gut Axis

Obesity is best understood as a multifactorial metabolic imbalances disorder. In a cross-sectional study, we aimed to explore sociodemographic and dietary determinants of obesity in relation to brain-gut homeostasis among overweight and obese individuals. Multivariate logistic regression models were used to examine obesity and its association with sociodemographic and dietary factors. Biological variables examined included the gut microbiome, fecal amino acid metabolites and brain structural volumes. Among 130 participants, there were higher odds of obesity if individuals were Hispanic (adjusted odds ratio (aOR) 1.56, p = 0.014). Compared to non-Hispanics, Hispanics differed in gut microbial composition (p = 0.046) with lower microbial species richness (Chao1) (p = 0.032) and evenness (Shannon) (p = 0.0029). Fourteen of the twenty fecal amino acids including branch-chain- and aromatic- amino acids were increased among Hispanics (q < 0.05). Brain structural volumes in reward regions were decreased in Hispanics (pallidum, q = 0.036; brainstem, q = 0.011). Correlation patterns suggest complex brain-gut interactions differ by Hispanic ethnicity. In conclusion, Hispanics expressed a unique brain-gut microbial signature, which was associated with obesity despite sociodemographic and dietary differences. Addressing ethnic disparities guided by biologic phenotypes may unlock novel understanding of obesity heterogeneity and treatment strategies.

Shifts in microbial diversity, composition, and functionality in the gut and genital microbiome during a natural SIV infection in vervet monkeys

BACKGROUND

The microbiota plays an important role in HIV pathogenesis in humans. Microbiota can impact health through several pathways such as increasing inflammation in the gut, metabolites of bacterial origin, and microbial translocation from the gut to the periphery which contributes to systemic chronic inflammation and immune activation and the development of AIDS. Unlike HIV-infected humans, SIV-infected vervet monkeys do not experience gut dysfunction, microbial translocation, and chronic immune activation and do not progress to immunodeficiency. Here, we provide the first reported characterization of the microbial ecosystems of the gut and genital tract in a natural nonprogressing host of SIV, wild vervet monkeys from South Africa.

RESULTS

We characterized fecal, rectal, vaginal, and penile microbiomes in vervets from populations heavily infected with SIV from diverse locations across South Africa. Geographic site, age, and sex affected the vervet microbiome across different body sites. Fecal and vaginal microbiome showed marked stratification with three enterotypes in fecal samples and two vagitypes, which were predicted functionally distinct within each body site. External bioclimatic factors, biome type, and environmental temperature influenced microbiomes locally associated with vaginal and rectal mucosa. Several fecal microbial taxa were linked to plasma levels of immune molecules, for example, MIG was positively correlated with Lactobacillus and Escherichia/Shigella and Helicobacter, and IL-10 was negatively associated with Erysipelotrichaceae, Anaerostipes, Prevotella, and Anaerovibrio, and positively correlated with Bacteroidetes and Succinivibrio. During the chronic phase of infection, we observed a significant increase in gut microbial diversity, alterations in community composition (including a decrease in Proteobacteria/Succinivibrio in the gut) and functionality (including a decrease in genes involved in bacterial invasion of epithelial cells in the gut), and partial reversibility of acute infection-related shifts in microbial abundance observed in the fecal microbiome. As part of our study, we also developed an accurate predictor of SIV infection using fecal samples.

CONCLUSIONS

The vervets infected with SIV and humans infected with HIV differ in microbial responses to infection. These responses to SIV infection may aid in preventing microbial translocation and subsequent disease progression in vervets, and may represent host microbiome adaptations to the virus. Video Abstract.

Analysis of brain networks and fecal metabolites reveals brain-gut alterations in premenopausal females with irritable bowel syndrome

Alterations in brain-gut-microbiome (BGM) interactions have been implicated in the pathogenesis of irritable bowel syndrome (IBS). Here, we apply a systems biology approach, leveraging neuroimaging and fecal metabolite data, to characterize BGM interactions that are driving IBS pathophysiology. Fecal samples and resting state fMRI images were obtained from 138 female subjects (99 IBS, 39 healthy controls (HCs)). Partial least-squares discriminant analysis (PLS-DA) was conducted to explore group differences, and partial correlation analysis explored significantly changed metabolites and neuroimaging data. All correlational tests were performed controlling for age, body mass index, and diet; results are reported after FDR correction, with q < 0.05 as significant. Compared to HCs, IBS showed increased connectivity of the putamen with regions of the default mode and somatosensory networks. Metabolite pathways involved in nucleic acid and amino acid metabolism differentiated the two groups. Only a subset of metabolites, primarily amino acids, were associated with IBS-specific brain changes, including tryptophan, glutamate, and histidine. Histidine was the only metabolite positively associated with both IBS-specific alterations in brain connectivity. Our findings suggest a role for several amino acid metabolites in modulating brain function in IBS. These metabolites may alter brain connectivity directly, by crossing the blood-brain-barrier, or indirectly through peripheral mechanisms. This is the first study to integrate both neuroimaging and fecal metabolite data supporting the BGM model of IBS, building the foundation for future mechanistic studies on the influence of gut microbial metabolites on brain function in IBS.

A Distinct Brain-Gut-Microbiome Profile Exists for Females with Obesity and Food Addiction

BACKGROUND

Alterations in brain-gut-microbiome interactions have been implicated as an important factor in obesity. This study aimed to explore the relationship between food addiction (FA) and the brain-gut-microbiome axis, using a multi-omics approach involving microbiome data, metabolomics, and brain imaging.

METHODS

Brain magnetic resonance imaging was obtained in 105 females. FA was defined by using the Yale Food Addiction Scale. Fecal samples were collected for sequencing and metabolomics. Statistical analysis was done by using multivariate analyses and machine learning algorithms.

RESULTS

Of the females with obesity, 33.3% exhibited FA as compared with 5.3% and 0.0% of females with overweight and normal BMI, respectively (P = 0.0001). Based on a multilevel sparse partial least square discriminant analysis, there was a difference in the gut microbiome of females with FA versus those without. Differential abundance testing showed Bacteroides, Megamonas, Eubacterium, and Akkermansia were statistically associated with FA (q < 0.05). Metabolomics showed that indolepropionic acid was inversely correlated with FA. FA was also correlated with increased connectivity within the brain's reward network, specifically between the intraparietal sulcus, brain stem, and putamen.

CONCLUSIONS

This is the first study to examine FA along the brain-gut-microbiome axis and it supports the idea of targeting the brain-gut-microbiome axis for the treatment of FA and obesity.

Gastrointestinal symptoms are predictive of trajectories of cognitive functioning in de novo Parkinson's disease

INTRODUCTION

Non-motor symptoms such as cognitive and gastrointestinal (GI) symptoms are common in Parkinson's disease (PD). In PD, GI-symptoms often present prior to motor symptoms. It is hypothesized that GI-symptoms reflect disruptions of the microbiome-gut-brain axis, which leads to altered immune functioning, chronic neuroinflammation, and subsequent neurodegeneration. Initial evidence links gut-dysbiosis to PD pathology and motor symptom severity. The present study examines the longitudinal relationship between severity of GI-symptoms and cognitive impairment in newly diagnosed PD patients.

METHODS

A secondary data analysis of the Parkinson's Progression Markers Initiative (PPMI) included 423 newly diagnosed PD patients who were followed for up to 5 years. Participants underwent neuropsychological tests of processing speed, attention, visuospatial functioning, verbal learning and verbal delayed recall. Participant were classified as cognitive intact, mild cognitive impairment or Parkinson's disease dementia. Frequency of GI-symptoms were assessed with the Scales for Outcomes in Parkinson's Disease Autonomic (SCOPA-AUT). Multi-level models (MLM) examined the longitudinal relationship between GI symptoms and cognitive impairment.

RESULTS

All cognitive outcomes were predicted by the main effect of GI symptoms, or the GI-symptom X Occasion interaction term. Specifically, more severe GI-symptoms were predictive of a less favorable trajectory of performance on tests of letter fluency, visuospatial, learning and memory. Cognitive performance was uniquely associated with GI-symptoms and unrelated to non-GI autonomic symptoms.

CONCLUSIONS

The presence of GI symptoms may serve as an early marker of cognitive impairment in PD. Future studies should examine specific mechanisms underlying the relationship between gut-dysbiosis and cognitive impairment.

Metformin alters the duodenal microbiome and decreases the incidence of pancreatic ductal adenocarcinoma promoted by diet-induced obesity

Pancreatic ductal adenocarcinoma (PDAC)'s growing incidence has been linked to the rise in obesity and type 2 diabetes mellitus. In previous work, we have shown that metformin can prevent the increased incidence of PDAC in a KrasG12D mouse model subjected to a diet high in fat and calories (HFCD). One potential way that metformin can affect the host is through alterations in the gut microbiome. Therefore, we investigated microbial associations with PDAC development and metformin use in the same mouse model. Lox-Stop-Lox Kras G12D/+ (LSL-Kras G12D/+); p48-Cre (KC) mice were given control diet, HFCD, or HFCD with 5 mg/mL metformin in drinking water for 3 mo. At the end of the 3 mo, 16S rRNA sequencing was performed to characterize microbiome composition of duodenal mucosal, duodenal luminal, and cecal luminal samples. KC mice on an HFCD demonstrated depletion of intact acini and formation of advanced pancreatic intraepithelial neoplasia. This effect was completely abrogated by metformin treatment. HFCD was associated with significant changes in microbial composition and diversity in the duodenal mucosa and lumen, much of which was prevented by metformin. In particular, Clostridium sensu stricto was negatively correlated with percent intact acini and seemed to be inhibited by the addition of metformin while on an HFCD. Administration of metformin eliminated PDAC formation in KC mice. This change was associated with significant microbial changes in both the mucosal and luminal microbiome of the duodenum. This suggests that the microbiome may be a potential mediator of the chemopreventive effects of metformin.NEW & NOTEWORTHY Pancreatic ductal adenocarcinoma (PDAC)'s growing incidence has been linked to the rise in obesity and type 2 diabetes mellitus. Administration of metformin eliminated PDAC formation in KC mice with diet-induced obesity. This change was associated with significant microbial changes in both the mucosal and luminal microbiome of the duodenum. This suggests that the microbiome may be a potential mediator of the chemopreventive effects of metformin.

Microbial Profiles of Cirrhosis in the Human Small Intestine

PURPOSE OF REVIEW

The aim of this review is to summarize the recent literature on associations of small intestinal microbial and bile acid profiles with liver cirrhosis and its complications.

RECENT FINDINGS

Recent studies into the duodenal microbiome of patients with cirrhosis have linked the microbiome to certain etiologies of chronic liver disease as well as complications of cirrhosis. In particular, microbial differences in the duodenum of patients with cirrhosis have been linked to the presence of hepatic encephalopathy and varices. While the fecal microbiome of patients with liver cirrhosis is well characterized, the small intestinal microbiome of cirrhotic patients is an active area of research. This review focuses on the current understanding of the small intestinal microbiome in human cirrhosis as well as future directions of the field.

Dietary Supplementation with Omega-3 Polyunsaturated Fatty Acids Reduces Opioid-Seeking Behaviors and Alters the Gut Microbiome

Opioids are highly addictive substances with a relapse rate of over 90%. While preclinical models of chronic opioid exposure exist for studying opioid dependence, none recapitulate the relapses observed in human opioid addiction. The mechanisms associated with opioid dependence, the accompanying withdrawal symptoms, and the relapses that are often observed months or years after opioid dependence are poorly understood. Therefore, we developed a novel model of chronic opioid exposure whereby the level of administration is self-directed with periods of behavior acquisition, maintenance, and then extinction alternating with reinstatement. This profile arguably mirrors that seen in humans, with initial opioid use followed by alternating periods of abstinence and relapse. Recent evidence suggests that dietary interventions that reduce inflammation, including omega-3 polyunsaturated fatty acids (n-3 PUFAs), may reduce substance misuse liability. Using the self-directed intake model, we characterize the observed profile of opioid use and demonstrate that an n-3-PUFA-enriched diet ameliorates oxycodone-seeking behaviors in the absence of drug availability and reduces anxiety. Guided by the major role gut microbiota have on brain function, neuropathology, and anxiety, we profile the microbiome composition and the effects of chronic opioid exposure and n-3 PUFA supplementation. We demonstrate that the withdrawal of opioids led to a significant depletion in specific microbiota genera, whereas n-3 PUFA supplementation increased microbial richness, phylogenetic diversity, and evenness. Lastly, we examined the activation state of microglia in the striatum and found that n-3 PUFA supplementation reduced the basal activation state of microglia. These preclinical data suggest that a diet enriched in n-3 PUFAs could be used as a treatment to alleviate anxiety induced opioid-seeking behavior and relapse in human opioid addiction.

Nonalcoholic fatty liver disease and the gut microbiome: Are bacteria responsible for fatty liver?

IMPACT STATEMENT

This invited minireview for the upcoming thematic issue on the microbiome addresses the role of the microbiome in nonalcoholic fatty liver disease (NAFLD). The incidence of NAFLD has increased greatly in recent years in parallel with the rise in obesity and is now believed to have a population prevalence of 20-40%. It is anticipated to soon become the primary cause of liver-related morbidity and mortality, and unfortunately, there are few treatment options. Therefore, there is a critical need for improved understanding of NAFLD pathophysiology to provide new avenues for therapeutic intervention. In this paper, we have reviewed evidence from human and animal model studies that have associated microbiome composition and microbial metabolites with development and progression of NAFLD. We have also discussed proposed mechanisms by which the microbiome could contribute to NAFLD pathogenesis and addressed future directions for this field.

Microbiotas from Humans with Inflammatory Bowel Disease Alter the Balance of Gut Th17 and RORγt+ Regulatory T Cells and Exacerbate Colitis in Mice

Microbiota are thought to influence the development and progression of inflammatory bowel disease (IBD), but determining generalizable effects of microbiota on IBD etiology requires larger-scale functional analyses. We colonized germ-free mice with intestinal microbiotas from 30 healthy and IBD donors and determined the homeostatic intestinal T cell response to each microbiota. Compared to microbiotas from healthy donors, transfer of IBD microbiotas into germ-free mice increased numbers of intestinal Th17 cells and Th2 cells and decreased numbers of RORγt+ Treg cells. Colonization with IBD microbiotas exacerbated disease in a model where colitis is induced upon transfer of naive T cells into Rag1-/- mice. The proportions of Th17 and RORγt+ Treg cells induced by each microbiota were predictive of human disease status and accounted for disease severity in the Rag1-/- colitis model. Thus, an impact on intestinal Th17 and RORγt+ Treg cell compartments emerges as a unifying feature of IBD microbiotas, suggesting a general mechanism for microbial contribution to IBD pathogenesis.

Microbiome and bile acid profiles in duodenal aspirates from patients with liver cirrhosis: The Microbiome, Microbial Markers and Liver Disease Study

AIM

Cirrhosis is a leading cause of death worldwide, yet there are no well-established risk stratifying tools for lethal complications, including hepatocellular carcinoma (HCC). Patients with liver cirrhosis undergo routine endoscopic surveillance, providing ready access to duodenal aspirate samples that could be a source for identifying novel biomarkers. The aim of this study was to characterize the microbiome and bile acid profiles in duodenal aspirates from patients with liver cirrhosis to assess the feasibility of developing biomarkers for HCC risk stratification.

METHODS

Thirty patients with liver cirrhosis were enrolled in the Microbiome, Microbial Markers, and Liver Disease study between May 2015 and March 2017. Detailed clinical and epidemiological data were collected at baseline and at 6-monthly follow-up visits. Duodenal aspirate fluid was collected at baseline for microbial characterization using 16S ribosomal RNA sequencing and bile acid quantification using mass spectroscopy.

RESULTS

Alcohol-related cirrhosis was associated with reductions in the Bacteroidetes phylum, particularly Prevotella (13-fold reduction), and expansion of Staphylococcus (13-fold increase), compared to hepatitis C virus-related cirrhosis. Participants with hepatic encephalopathy (HE) had less microbial diversity compared to patients without HE (P < 0.05), and were characterized by expansion of Mycobacterium (45-fold increase) and Gram-positive cocci including Granulicatella (3.1-fold increase), unclassified Planococcaceae (3.3-fold increase), and unclassified Streptococcaceae (4.5-fold increase). Non-Hispanic White patients had reduced microbial richness (P < 0.01) and diversity (P < 0.05), and increased levels of conjugated ursodeoxycholic acid (glycoursodeoxycholic acid and tauroursodeoxycholic acid, P < 0.05) compared to Hispanic patients.

CONCLUSION

Microbial profiles of duodenal aspirates differed by cirrhosis etiology, HE, and Hispanic ethnicity.

Ceragenin CSA13 Reduces Clostridium difficile Infection in Mice by Modulating the Intestinal Microbiome and Metabolites

BACKGROUND & AIMS

Clostridium difficile induces intestinal inflammation by releasing toxins A and B. The antimicrobial compound cationic steroid antimicrobial 13 (CSA13) has been developed for treating gastrointestinal infections. The CSA13-Eudragit formulation can be given orally and releases CSA13 in the terminal ileum and colon. We investigated whether this form of CSA13 reduces C difficile infection (CDI) in mice.

METHODS

C57BL/6J mice were infected with C difficile on day 0, followed by subcutaneous administration of pure CSA13 or oral administration of CSA13-Eudragit (10 mg/kg/d for 10 days). Some mice were given intraperitoneal vancomycin (50 mg/kg daily) on days 0-4 and relapse was measured after antibiotic withdrawal. The mice were monitored until day 20; colon and fecal samples were collected on day 3 for analysis. Blood samples were collected for flow cytometry analyses. Fecal pellets were collected each day from mice injected with CSA13 and analyzed by high-performance liquid chromatography or 16S sequencing; feces were also homogenized in phosphate-buffered saline and fed to mice with CDI via gavage.

RESULTS

CDI of mice caused 60% mortality, significant bodyweight loss, and colonic damage 3 days after infection; these events were prevented by subcutaneous injection of CSA13 or oral administration CSA13-Eudragit. There was reduced relapse of CDI after administration of CSA13 was stopped. Levels of CSA13 in feces from mice given CSA13-Eudragit were significantly higher than those of mice given subcutaneous CSA13. Subcutaneous and oral CSA13 each significantly increased the abundance of Peptostreptococcaceae bacteria and reduced the abundance of C difficile in fecal samples of mice. When feces from mice with CDI and given CSA13 were fed to mice with CDI that had not received CSA13, the recipient mice had significantly increased rates of survival. CSA13 reduced fecal levels of inflammatory metabolites (endocannabinoids) and increased fecal levels of 4 protective metabolites (ie, citrulline, 3-aminoisobutyric acid, retinol, and ursodeoxycholic acid) in mice with CDI. Oral administration of these CSA13-dependent protective metabolites reduced the severity of CDI.

CONCLUSIONS

In studies of mice, we found the CSA13-Eudragit formulation to be effective in eradicating CDI by modulating the intestinal microbiota and metabolites.

CSA13 inhibits colitis-associated intestinal fibrosis via a formyl peptide receptor like-1 mediated HMG-CoA reductase pathway

Many Crohn’s disease (CD) patients develop intestinal strictures, which are difficult to prevent and treat. Cationic steroid antimicrobial 13 (CSA13) shares cationic nature and antimicrobial function with antimicrobial peptide cathelicidin. As many functions of cathelicidin are mediated through formyl peptide receptor-like 1 (FPRL1), we hypothesize that CSA13 mediates anti-fibrogenic effects via FPRL1. Human intestinal biopsies were used in clinical data analysis. Chronic trinitrobenzene sulfonic acid (TNBS) colitis-associated intestinal fibrosis mouse model with the administration of CSA13 was used. Colonic FPRL1 mRNA expression was positively correlated with the histology scores of inflammatory bowel disease patients. In CD patients, colonic FPRL1 mRNA was positively correlated with intestinal stricture. CSA13 administration ameliorated intestinal fibrosis without influencing intestinal microbiota. Inhibition of FPRL1, but not suppression of intestinal microbiota, reversed these protective effects of CSA13. Metabolomic analysis indicated increased fecal mevalonate levels in the TNBS-treated mice, which were reduced by the CSA13 administration. CSA13 inhibited colonic HMG-CoA reductase activity in an FPRL1-dependent manner. Mevalonate reversed the anti-fibrogenic effect of CSA13. The increased colonic FPRL1 expression is associated with severe mucosal disease activity and intestinal stricture. CSA13 inhibits intestinal fibrosis via FPRL1-dependent modulation of HMG-CoA reductase pathway.

High-protein diet improves sensitivity to cholecystokinin and shifts the cecal microbiome without altering brain inflammation in diet-induced obesity in rats

High-protein diet (HPD) curtails obesity and/or fat mass, but it is unknown whether it reverses neuroinflammation or alters glucose levels, CCK sensitivity, and gut microbiome in rats fed a Western diet (WD)-induced obesity (DIO). Male rats fed a WD (high fat and sugar) for 12 wk were switched to a HPD for 6 wk. Body composition, food intake, meal pattern, sensitivity to intraperitoneal CCK-8S, blood glucose, brain signaling, and cecal microbiota were assessed. When compared with a normal diet, WD increased body weight (9.3%) and fat mass (73.4%). CCK-8S (1.8 or 5.2 nmol/kg) did not alter food intake and meal pattern in DIO rats. Switching to a HPD for 6 wk reduced fat mass (15.7%) with a nonsignificantly reduced body weight gain, normalized blood glucose, and decreased feeding after CCK-8S. DIO rats on the WD or switched to a HPD showed comparable microbial diversity. However, in HPD versus WD rats, there was enrichment of 114 operational taxonomic units (OTUs) and depletion of 188 OTUs. Of those, Akkermansia muciniphila (enriched on a HPD), an unclassified Clostridiales, a member of the RF39 order, and a Phascolarctobacterium were significantly associated with fat mass. The WD increased cytokine expression in the hypothalamus and dorsal medulla that was unchanged by switching to HPD. These data indicate that HPD reduces body fat and restores glucose homeostasis and CCK sensitivity, while not modifying brain inflammation. In addition, expansion of cecal Akkermansia muciniphila correlated to fat mass loss may represent a potential peripheral mechanism of HPD beneficial effects.

Association of Systemic Sclerosis With a Unique Colonic Microbial Consortium

OBJECTIVE

To compare colonic microbial composition in systemic sclerosis (SSc) patients and healthy controls and to determine whether certain microbial genera are associated with gastrointestinal (GI) tract symptoms in patients with SSc.

METHODS

Healthy controls were age- and sex-matched (1:1) with adult SSc patients. Cecum and sigmoid mucosal lavage samples were obtained during colonoscopy. The microbiota in these samples were determined by Illumina HiSeq 2000 16S sequencing, and operational taxonomic units were selected. Linear discriminant analysis effect size was used to identify the genera that showed differential expression in SSc patients versus controls. Differential expression analysis for sequence count data was used to identify specific genera associated with GI tract symptoms.

RESULTS

Among 17 patients with SSc (88% female; median age 52.1 years), the mean ± SD total GI Tract 2.0 score was 0.7 ± 0.6. Principal coordinate analysis illustrated significant differences in microbial communities in the cecum and sigmoid regions in SSc patients versus healthy controls (both P = 0.001). Similar to the findings in inflammatory disease states, SSc patients had decreased levels of commensal bacteria, such as Faecalibacterium and Clostridium, and increased levels of pathobiont bacteria, such as Fusobacterium and γ-Proteobacteria, compared with healthy controls. Bifidobacterium and Lactobacillus, which are typically reduced under conditions of inflammation, were also increased in abundance in patients with SSc. In SSc patients with moderate/severe GI tract symptoms, the abundance of Bacteroides fragilis was decreased, and that of Fusobacterium was increased, compared with patients who had no or mild symptoms.

CONCLUSION

This study demonstrates a distinct colonic microbial signature in SSc patients compared with healthy controls. This unique ecologic change may perpetuate immunologic aberrations and contribute to clinical manifestations of SSc.

Systemic sclerosis is associated with specific alterations in gastrointestinal microbiota in two independent cohorts

OBJECTIVE

To compare faecal microbial composition in patients with systemic sclerosis (SSc) from 2 independent cohorts with controls and to determine whether certain genera are associated with SSc-gastrointestinal tract (GIT) symptoms.

DESIGN

Adult patients with SSc from the University of California, Los Angeles (UCLA) and Oslo University Hospital (OUH) and healthy controls participated in this study (1:1:1). All participants provided stool specimens for 16S rRNA sequencing. Linear discriminant analysis effect size demonstrated genera with differential expression in SSc. Differential expression analysis for sequence count data identified specific genera associated with GIT symptoms as assessed by the GIT 2.0 questionnaire.

RESULTS

The UCLA-SSc and OUH-SSc cohorts were similar in age (52.1 and 60.5 years, respectively), disease duration (median (IQR): 6.6 (2.5-16.4) and 7.0 (1.0-19.2) years, respectively), gender distribution (88% and 71%, respectively), and GIT symptoms (mean (SD) total GIT 2.0 scores of 0.7 (0.6) and 0.6 (0.5), respectively). Principal coordinate analysis illustrated significant microbial community differences between SSc and controls (UCLA: p=0.001; OUH: p=0.002). Patients with SSc had significantly lower levels of commensal genera deemed to protect against inflammation, such as Bacteroides (UCLA and OUH), Faecalibacterium (UCLA), Clostridium (OUH); and significantly higher levels of pathobiont genera, such as Fusobacterium (UCLA), compared with controls. Increased abundance of Clostridium was associated with less severe GIT symptoms in both cohorts.

CONCLUSIONS

The present analysis detected specific aberrations in the lower GIT microbiota of patients with SSc from 2 geographically and ethnically distinct cohorts. These findings suggest that GIT dysbiosis may be a pathological feature of the SSc disease state.

Chronic Early-life Stress in Rat Pups Alters Basal Corticosterone, Intestinal Permeability, and Fecal Microbiota at Weaning: Influence of Sex

Background/Aims

Wistar rat dams exposed to limited nesting stress (LNS) from post-natal days (PND) 2 to 10 display erratic maternal behavior, and their pups show delayed maturation of the hypothalamic-pituitary-adrenal axis and impaired epithelial barrier at PND10 and a visceral hypersensitivity at adulthood. Little is known about the impact of early life stress on the offspring before adulthood and the influence of sex. We investigated whether male and female rats previously exposed to LNS displays at weaning altered corticosterone, intestinal permeability, and microbiota.

Methods

Wistar rat dams and litters were maintained from PND2 to 10 with limited nesting/bedding materials and thereafter reverted to normal housing up to weaning (PND21). Control litters had normal housing. At weaning, we monitored body weight, corticosterone plasma levels (enzyme immunoassay), in vivo intestinal to colon permeability (fluorescein isothiocyanate-dextran 4 kDa) and fecal microbiota (DNA extraction and amplification of the V4 region of the 16S ribosomal RNA gene).

Results

At weaning, LNS pups had hypercorticosteronemia and enhanced intestinal permeability with females > males while body weights were similar. LNS decreased fecal microbial diversity and induced a distinct composition characterized by increased abundance of Gram positive cocci and reduction of fiber-degrading, butyrate-producing, and mucus-resident microbes.

Conclusions

These data indicate that chronic exposure to LNS during the first week post-natally has sustained effects monitored at weaning including hypercorticosteronemia, a leaky gut, and dysbiosis. These alterations may impact on the susceptibility to develop visceral hypersensitivity in adult rats and have relevance to the development of irritable bowel syndrome in childhood.

Microbial, metabolomic, and immunologic dynamics in a relapsing genetic mouse model of colitis induced by T-synthase deficiency

Intestinal dysbiosis is thought to confer susceptibility to inflammatory bowel disease (IBD), but it is unknown whether dynamic changes in the microbiome contribute to fluctuations in disease activity. We explored this question using mice with intestine-specific deletion of C1galt1 (also known as T-synthase) (Tsyn mice). These mice develop spontaneous microbiota-dependent colitis with a remitting/relapsing course due to loss of mucin core-1 derived O-glycans. 16S rRNA sequencing and untargeted metabolomics demonstrated age-specific perturbations in the intestinal microbiome and metabolome of Tsyn mice compare with littermate controls at weeks 3 (disease onset), 5 (during remission), and 9 (after relapse). Colitis remission corresponded to increased levels of FoxP3+RORγt+CD4+ T cells in the colonic lamina propria that were positively correlated with operational taxonomic units (OTUs) in the S24-7 family and negatively correlated with OTUs in the Clostridiales order. Relapse was characterized by marked expansion of FoxP3-RORγt+CD4+ T cells expressing IFNγ and IL17A, which were associated with Clostridiales OTUs distinct from those negatively correlated with FoxP3+RORγt+CD4+ T cells. Our findings suggest that colitis remission and relapse in the Tsyn model may reflect alterations in the microbiome due to reduced core-1 O-glycosylation that shift the balance of regulatory and pro-inflammatory T cell subsets. We investigated whether genetic variation in C1galt1 correlated with the microbiome in a cohort of 78 Crohn's disease patients and 101 healthy controls. Polymorphisms near C1galt1 (rs10486157) and its molecular chaperone, Cosmc (rs4825729), were associated with altered composition of the colonic mucosal microbiota, supporting the relevance of core-1 O-glycosylation to host regulation of the microbiome.

A Pleiotropic Missense Variant in SLC39A8 Is Associated With Crohn's Disease and Human Gut Microbiome Composition

BACKGROUND & AIMS

Genome-wide association studies have identified 200 inflammatory bowel disease (IBD) loci, but the genetic architecture of Crohn's disease (CD) and ulcerative colitis remain incompletely defined. Here, we aimed to identify novel associations between IBD and functional genetic variants using the Illumina ExomeChip (San Diego, CA).

METHODS

Genotyping was performed in 10,523 IBD cases and 5726 non-IBD controls. There were 91,713 functional single-nucleotide polymorphism loci in coding regions analyzed. A novel identified association was replicated further in 2 independent cohorts. We further examined the association of the identified single-nucleotide polymorphism with microbiota from 338 mucosal lavage samples in the Mucosal Luminal Interface cohort measured using 16S sequencing.

RESULTS

We identified an association between CD and a missense variant encoding alanine or threonine at position 391 in the zinc transporter solute carrier family 39, member 8 protein (SLC39A8 alanine 391 threonine, rs13107325) and replicated the association with CD in 2 replication cohorts (combined meta-analysis P = 5.55 × 10(-13)). This variant has been associated previously with distinct phenotypes including obesity, lipid levels, blood pressure, and schizophrenia. We subsequently determined that the CD risk allele was associated with altered colonic mucosal microbiome composition in both healthy controls (P = .009) and CD cases (P = .0009). Moreover, microbes depleted in healthy carriers strongly overlap with those reduced in CD patients (P = 9.24 × 10(-16)) and overweight individuals (P = 6.73 × 10(-16)).

CONCLUSIONS

Our results suggest that an SLC39A8-dependent shift in the gut microbiome could explain its pleiotropic effects on multiple complex diseases including CD.

An Integrated Multi-Omic Approach to Assess Radiation Injury on the Host-Microbiome Axis

Medical responders to radiological and nuclear disasters currently lack sufficient high-throughput and minimally invasive biodosimetry tools to assess exposure and injury in the affected populations. For this reason, we have focused on developing robust radiation exposure biomarkers in easily accessible biofluids such as urine, serum and feces. While we have previously reported on urine and serum biomarkers, here we assessed perturbations in the fecal metabolome resulting from exposure to external X radiation in vivo. The gastrointestinal (GI) system is of particular importance in radiation biodosimetry due to its constant cell renewal and sensitivity to radiation-induced injury. While the clinical GI symptoms such as pain, bloating, nausea, vomiting and diarrhea are manifested after radiation exposure, no reliable bioindicator has been identified for radiation-induced gastrointestinal injuries. To this end, we focused on determining a fecal metabolomic signature in X-ray irradiated mice. There is overwhelming evidence that the gut microbiota play an essential role in gut homeostasis and overall health. Because the fecal metabolome is tightly correlated with the composition and diversity of the microorganism in the gut, we also performed fecal 16S rRNA sequencing analysis to determine the changes in the microbial composition postirradiation. We used in-house bioinformatics tools to integrate the 16S rRNA sequencing and metabolomic data, and to elucidate the gut integrated ecosystem and its deviations from a stable host-microbiome state that result from irradiation. The 16S rRNA sequencing results indicated that radiation caused remarkable alterations of the microbiome in feces at the family level. Increased abundance of common members of Lactobacillaceae and Staphylococcaceae families, and decreased abundances of Lachnospiraceae, Ruminococcaceae and Clostridiaceae families were found after 5 and 12 Gy irradiation. The metabolomic data revealed statistically significant changes in the microbial-derived products such as pipecolic acid, glutaconic acid, urobilinogen and homogentisic acid. In addition, significant changes were detected in bile acids such as taurocholic acid and 12-ketodeoxycholic acid. These changes may be associated with the observed shifts in the abundance of intestinal microbes, such as R. gnavus , which can transform bile acids.

A Disease-Associated Microbial and Metabolomics State in Relatives of Pediatric Inflammatory Bowel Disease Patients

BACKGROUND & AIMS

Microbes may increase susceptibility to inflammatory bowel disease (IBD) by producing bioactive metabolites that affect immune activity and epithelial function. We undertook a family based study to identify microbial and metabolic features of IBD that may represent a predisease risk state when found in healthy first-degree relatives.

METHODS

Twenty-one families with pediatric IBD were recruited, comprising 26 Crohn's disease patients in clinical remission, 10 ulcerative colitis patients in clinical remission, and 54 healthy siblings/parents. Fecal samples were collected for 16S ribosomal RNA gene sequencing, untargeted liquid chromatography-mass spectrometry metabolomics, and calprotectin measurement. Individuals were grouped into microbial and metabolomics states using Dirichlet multinomial models. Multivariate models were used to identify microbes and metabolites associated with these states.

RESULTS

Individuals were classified into 2 microbial community types. One was associated with IBD but irrespective of disease status, had lower microbial diversity, and characteristic shifts in microbial composition including increased Enterobacteriaceae, consistent with dysbiosis. This microbial community type was associated similarly with IBD and reduced microbial diversity in an independent pediatric cohort. Individuals also clustered bioinformatically into 2 subsets with shared fecal metabolomics signatures. One metabotype was associated with IBD and was characterized by increased bile acids, taurine, and tryptophan. The IBD-associated microbial and metabolomics states were highly correlated, suggesting that they represented an integrated ecosystem. Healthy relatives with the IBD-associated microbial community type had an increased incidence of elevated fecal calprotectin.

CONCLUSIONS

Healthy first-degree relatives can have dysbiosis associated with an altered intestinal metabolome that may signify a predisease microbial susceptibility state or subclinical inflammation. Longitudinal prospective studies are required to determine whether these individuals have a clinically significant increased risk for developing IBD.

Immune and genetic gardening of the intestinal microbiome

The mucosal immune system - consisting of adaptive and innate immune cells as well as the epithelium - is profoundly influenced by its microbial environment. There is now growing evidence that the converse is also true, that the immune system shapes the composition of the intestinal microbiome. During conditions of health, this bidirectional interaction achieves a homeostasis in which inappropriate immune responses to non-pathogenic microbes are averted and immune activity suppresses blooms of potentially pathogenic microbes (pathobionts). Genetic alteration in immune/epithelial function can affect host gardening of the intestinal microbiome, contributing to the diversity of intestinal microbiota within a population and in some cases allowing for unfavorable microbial ecologies (dysbiosis) that confer disease susceptibility.

Sampling of intestinal microbiota and targeted amplification of bacterial 16S rRNA genes for microbial ecologic analysis

Dysbiosis of host-associated commensal microbiota is emerging as an important factor in risk and phenotype of immunologic, metabolic, and behavioral diseases. Accurate analysis of microbial composition and functional state in humans or mice requires appropriate collection and pre-processing of biospecimens. Methods to sample luminal and mucosal microbiota from human or mouse intestines and to profile microbial phylogenetic composition using 16S rRNA sequencing are presented here. Data generated using the methods in this unit can be used for downstream quantitative analysis of microbial ecology.

Deficiency of CXCR2, but not other chemokine receptors, attenuates autoantibody-mediated arthritis in a murine model

OBJECTIVE

Chemokines coordinate leukocyte trafficking in homeostasis and during immune responses. Prior studies of their role in arthritis have used animal models with both an initial adaptive immune response and an inflammatory effector phase. We undertook analysis of chemokines and their receptors in the effector phase of arthritis using the K/BxN mouse serum-transfer model.

METHODS

A time-course microarray analysis of serum-transferred arthritis was performed, examining ankle tissue, synovial fluid, and peripheral blood leukocytes. Up-regulation of chemokines was confirmed by quantitative reverse transcriptase-polymerase chain reaction. The functional relevance of chemokine induction was assessed by transferring serum into mice deficient in CCR1-7, CCR9, CXCR2, CXCR3, CXCR5, CX(3)CR1, CCL2, or CCL3. Further mechanistic analysis of CXCR2 involved treatment of arthritic mice with a CXCR2 antagonist, bone marrow (BM) cell transfers with CXCR2(+/-) and CXCR2(-/-) donors and recipients, flow cytometry of synovial cells, and competition experiments measuring enrichment of CXCR2-expressing neutrophils in arthritic joints of mice with mixed CXCR2(+/+) and CXCR2(-/-) BM cells.

RESULTS

Gene expression profiling revealed up-regulation of the CXCR2 ligands CXCL1, CXCL2, and CXCL5 in the joint in parallel with disease activity. CXCR2(-/-) mice had attenuated disease relative to CXCR2(+/-) littermates, as did mice receiving the CXCR2 inhibitor, while deficiency of other chemokine receptors did not affect arthritis severity. CXCR2 was required only on hematopoietic cells and was widely expressed on synovial neutrophils. CXCR2-expressing neutrophils were preferentially recruited to arthritic joints in the presence of CXCR2-deficient neutrophils.

CONCLUSION

CXCR2 (but not other chemokine receptors) is critical for the development of autoantibody-mediated arthritis, exhibiting a cell-autonomous role in neutrophil recruitment to inflamed joints.

Circulating C3 is necessary and sufficient for induction of autoantibody-mediated arthritis in a mouse model

Objective

For the inflammation characteristic of rheumatoid arthritis, the relative contribution of mediators produced locally in the synovium versus those circulating systemically is unknown. Complement factor C3 is made in rheumatoid synovium and has been proposed to be a crucial driver of inflammation. The aim of this study was to test, in a mouse model of rheumatoid arthritis, whether C3 synthesized within the synovium is important in promoting inflammation.

Methods

Radiation bone marrow chimeras between normal and C3^−/− mice were constructed in order to generate animals that expressed or lacked expression of C3 only in hematopoietic cells. Parabiotic mice were made by surgically linking C3^−/− mice to irradiated wild-type mice to obtain animals having C3 only in the circulation. Arthritis was induced by injection of serum from arthritic K/BxN mice.

Results

In bone marrow chimeras, synthesis of C3 by radioresistant cells was necessary and sufficient to confer susceptibility to serum-transferred arthritis. Parabionts having C3 only in the circulation remained sensitive to arthritis induction, and the cartilage of these arthritic mice contained deposits of C3.

Conclusion

In a mouse model in which the alternative pathway of complement activation is critical to the induction of arthritis by autoantibodies, circulating C3 was necessary and sufficient for arthritis induction.

Lack of requirement of osteopontin for inflammation, bone erosion, and cartilage damage in the K/BxN model of autoantibody-mediated arthritis

OBJECTIVE

Osteopontin (OPN) is a secreted glycoprotein involved in a range of physiologic processes, including inflammation, immunity mediated by Th1 cells, and bone remodeling. It is expressed in the joints of rheumatoid arthritis patients and has been the subject of conflicting reports concerning its role in arthritis induced by antibodies against type II collagen. This study assessed the role of OPN in the K/BxN serum-transfer model of autoantibody-induced arthritis.

METHODS

Expression of OPN gene transcripts was assessed by microarray analysis of ankle RNA taken at 6 time points after transfer of K/BxN serum. OPN-sufficient or OPN-deficient littermates backcrossed for 10 generations onto the C57BL/6 genetic background were given K/BxN serum. Arthritis severity was measured by ankle thickening and a clinical index. Hind limb sections were stained with hematoxylin and eosin or toluidine blue and scored for inflammation, cartilage damage, and bone erosion.

RESULTS

OPN messenger RNA transcripts progressively increased in ankle joints during the course of K/BxN serum-transferred arthritis. OPN-deficient mice receiving K/BxN serum developed arthritis with kinetics and clinical severity comparable with those of OPN-sufficient littermates. Histologic assessment of arthritic joints from OPN-deficient mice revealed synovial hyperplasia, pannus formation, mononuclear cell infiltration, bone erosion, cartilage damage at sites adjacent to and distal from pannus invasion, and tartrate-resistant acid phosphatase-positive multinucleated cells at sites of bone erosion. Histopathologic scoring demonstrated comparable levels of inflammation, cartilage damage, and bone erosion in OPN-sufficient and OPN-deficient mice.

CONCLUSION

OPN does not have a required role in inflammation, bone erosion, and cartilage damage in the K/BxN serum-transfer model.

Association of segmentation of the epididymal interstitium with segmented tubule function in rats and mice

The epithelium of the epididymal tubule has different biological functions in different regions of the tubule. Each region is further organized into lobules or intra-regional segments surrounded by connective tissue septa (CTS). Epididymal segmentation has received little direct attention, yet there is considerable evidence that expression of mRNA and protein often begins or ends precisely at the CTS border of a segment. How such 'on-off' regulation occurs coincident with the passing of the tubule from one segment to the next is unknown. This study examined the segmentation of epididymides in rats and mice. The average adult Sprague-Dawley rat and C57BL/6 mouse caput, corpus and cauda epididymides has seven, two and four, and three, one and two segments, respectively. The apoptosis response of the caput epididymal epithelium to deprivation of lumicrine factors 24 h after efferent duct ligation in rats and the epididymal expression of a marker protein, beta-galactosidase, in mice were segmented precisely. This validated both at a general response and at a specific protein level that many epididymal functions are regulated within segments. Blue dextran (molecular weight 20000) and erythrocine red (molecular weight 880) dyes infused into the interstitial space of specific segments by micropuncture were retained by the CTS of the segments. In similar micropuncture experiments, [(3)H]H(2)O (molecular weight 18) was able to diffuse into an adjacent segment relatively freely whereas [(14)C]polyethylene glycol (molecular weight 4000) could not. These studies indicate that the interstitium of intra-regional segments is organized into different physiological compartments and that these compartments play a role in regulating the epididymal epithelium.

Management of glucocorticoid-induced osteoporosis in patients with rheumatoid arthritis: rates and predictors of care in an academic rheumatology practice

OBJECTIVE

To examine rheumatologists' management practices for patients with rheumatoid arthritis (RA) taking glucocorticoids seen at one academic medical rheumatology practice.

METHODS

All patients diagnosed with RA making at least 2 visits to the practice who were noted to be taking glucocorticoids on an index visit in January or February 1999 were included in a retrospective chart review.

RESULTS

Of the 623 eligible patients identified with RA, 236 patients were taking glucocorticoids at their index visit and were included in this study. The mean daily dosage of prednisone (or its equivalent) was 8.8 mg and the mean duration of use during the 2-year chart review was 15.4 months. Twenty-three percent of the study population underwent bone densitometry, and 42% were prescribed a medication that reduces bone loss (not including calcium and/or vitamin D). Calcium and/or vitamin D were noted on the medication lists of 25% of patients. Factors associated with not undergoing bone densitometry in adjusted logistic models included male patient sex and premenopausal status in women. No physician factors were significantly related to performing bone densitometry. Variables associated with not receiving prescription treatment of osteoporosis were male patient sex, premenopausal status, and having at least 1 comorbid condition.

CONCLUSION

Patients with RA taking oral glucocorticoids did not routinely undergo bone densitometry and/or receive prescription medications for osteoporosis. Men and premenopausal women were less likely to undergo bone densitometry and to receive a prescription medication for osteoporosis than postmenopausal women. Interventions to improve detection and prevention of glucocorticoid-induced osteoporosis are necessary.

Assisted venous drainage cardiopulmonary bypass in congenital heart surgery

BACKGROUND

A novel active venous drainage perfusion circuit was designed to achieve effective venous return through small venous cannulas. The efficacy and safety of this new system was investigated and compared with a conventional gravity drainage system.

METHODS

Four hundred consecutive patients undergoing open heart repair of congenital heart lesions by one surgeon were studied. The first 200 patients were supported by gravity drainage and the next 200 patients were supported by assisted venous drainage. No patient in the time period was excluded from the study.

RESULTS

The two groups did not differ significantly in weight, bypass time, or cross-clamp time. Priming volumes were less in the assisted group than in the gravity group (576+/-232 mL versus 693+/-221 mL, p < 0.001). Venous cannula size was smaller in the assisted group when compared with the gravity group (33.2F+/-7.4F versus 38.5F+/-7.1F, p < 0.001). There was a trend to lower operative mortality in the assisted drainage group (5 of 200, 2.5% versus 11 of 200, 5.5%; p = 0.10). Hospital stay and pulmonary, infectious, and neurologic complications were comparable in both groups. Cardiac complications were less common in the assisted group than in gravity group (22 of 200, 11% versus 38 of 200, 19%; p = 0.017). Hematologic complications were less common in the assisted group than the gravity group (6 of 200, 3% versus 19 of 200, 9.5%; p < 0.01).

CONCLUSIONS

These findings suggest that assisted venous drainage is safe in congenital heart operations and facilitates the use of smaller venous cannulas.

New limit on the permanent electric dipole moment of 199Hg

We present the first results of a new search for a permanent electric dipole moment of the 199Hg atom using a UV laser. Our measurements give d(199Hg) = -(1.06+/-0.49+/-0.40)x10(-28)e cm. We interpret the result as an upper limit absolute value [d(199Hg)]<2.1x10(-28)e cm (95% C.L.), which sets new constraints on theta bar;(QCD), chromo-EDMs of the quarks, and CP violation in supersymmetric models.

The role of airway stents in the management of pediatric tracheal, carinal, and bronchial disease

OBJECTIVE

A variety of stents are available to aid in the management of complex tracheal, carinal and bronchial stenoses. We reviewed our multi-institutional experience with airway stents in children.

METHODS

Thirty-three children (age, 13 days-18 years) from four institutions have had a total of 40 stents placed to aid in the management of complex airway stenoses. Three stent types were utilized: 29 silastic stents, five expandable metal stents and six customized carinal stents (four patients had two stents and one patient had four stents). Thirty children had tracheal stents, six children had bronchial stents, and two infants had carinal stents (three children had stenting of more than one area and two had stenting of all three locations). Twenty-eight patients (age, 5 months-18 years; mean, 8.06 years; SEM, 1.13 years) had stents placed after a variety of airway reconstructive procedures. Four underwent stenting in a non-operative setting and one as preoperative stabilization.

RESULTS

Twenty-seven patients survived. One patient died early due to bleeding. Five patients died late: two due to bleeding, one from mediastinitis, and two patients with functional airways died late from unrelated problems. Complications are related to stent type and location. Carinal stents can migrate; several techniques are available to help manage this problem. Wire stents are essentially non-removable requiring periodic dilation. Silastic stents stimulate granulation tissue formation requiring periodic bronchoscopic removal.

CONCLUSION

Tracheal stenting can aid in the management of pediatric airway problems. Complications are common, but can be managed with appropriate intervention.

Rapid cardiopulmonary support for children with complex congenital heart disease

BACKGROUND

Extracorporeal membrane oxygenation has limitations in children with congenital heart disease (prolonged setup times, increased postoperative blood loss, and difficulty during transport). We developed a miniaturized cardiopulmonary support circuit to address these limitations.

PATIENTS AND METHODS

The cardiopulmonary support system includes a preassembled, completely heparin-coated circuit, a BP-50 Bio-Medicus centrifugal pump, a Minimax plus membrane oxygenator, a Bio-Medicus flow probe, and a Bio-trend hematocrit/oxygen saturation monitor. Short tubing length permits a 250-mL bloodless prime in less than 5 minutes. From 1995 to 1997, 23 children with congenital heart disease were supported with this technique.

RESULTS

Overall survival to discharge was 48% (11 of 23 patients). Survival to discharge was 80% (4 of 5) in the preoperative support group, 20% (1 of 5) in the postoperative failure to wean from cardiopulmonary bypass group, 44% (4 of 9) in the group placed on support postoperatively after transfer to the intensive care unit, and 50% (2 of 4 patients) in the nonoperative group. Neonatal cardiopulmonary support survival to discharge was 46% (6 of 13 patients).

CONCLUSIONS

This pediatric cardiopulmonary support system is safe and effective. Advantages over conventional extracorporeal membrane oxygenation include rapid setup time, decreased postoperative blood loss, and simplified transport.

Presentation of the International Nomenclature for Congenital Heart Surgery. The long way from nomenclature to collection of validated data at the EACTS

An International Nomenclature for Congenital Heart Surgery was officially adopted at the Annual Meeting of the EACTS in Glasgow, UK on September 6, 1999. This nomenclature was achieved following 1 year's work of the International Nomenclature and Data Base Committee for Congenital Heart Surgery of the Society of Thoracic Surgeons. This international group included members from the STS, AATS, AHA and EACTS and associated surgeons and cardiologists from United States, Canada, Australia and Europe. The Nomenclature includes a minimal data set of 21 items and lists of 150 diagnoses, 200 procedures, 32 complications and 28 extra cardiac anomalies and preoperative risk factors. It will serve as a basis for the Pediatric European Cardiac Surgical Registry (http://www.pediatric. ecsur.org). The outcome of such an International Nomenclature represents an important event for the medical community in charge of treating patients with congenital heart diseases. It will allow scientific exchanges on an international scale and promote multicenter evaluation of congenital heart surgery. Nevertheless, this Nomenclature is only the first step. Further collection of validated data at the Pediatric ECSUR Data Base requires ethical belief, time consumption and financial resources. Comparison of results, according to pathologies, across centers and countries will help define, in the future, official European standards of Quality of Care available for health care organizations, public scrutiny and governmental agencies.

Heparin-coated cardiopulmonary bypass circuit: clinical effects in pediatric cardiac surgery

OBJECTIVES

Heparin-coated cardiopulmonary bypass (CPB) circuits have been reported to reduce complement activation and the inflammatory response associated with CPB. We retrospectively compared patients utilizing heparin-coated perfusion circuits with those using noncoated circuits to determine the clinical effects of the different circuits in pediatric cardiac surgery.

METHODS

Between July 1995 and July 1997, 203 patients weighing < 10 kg underwent cardiac surgery, 153 patients using heparin-coated bypass circuits and 50 patients using noncoated circuits. The 50 patients operated on with the noncoated circuit (Group N) were matched to 100 patients operated on with coated circuits (Group H) in age, weight, and type of procedure. Urine output during bypass, blood products used after bypass, postoperative ventilation days, hospital stay, morbidity, and mortality were compared between these groups.

RESULTS

Body weight, perfusion time, and procedure time were not different between the two groups. Urine output during bypass was notably greater in Group H than in Group N (11.3 +/- 10.5 mL/kg per hour vs 4.8 +/- 3.1 mL/kg per hour, respectively, p < 0.0001). Postoperative mechanical ventilation markedly decreased in Group H (Group H vs N = 2.8 +/- 2.7 days vs 5.1 +/- 7.5 days, respectively, p < 0.05). Red blood cell usage, hospital stay, morbidity, and mortality were not statistically different, although there was a tendency toward decreased transfusion of red cell and platelets in Group H (Group H vs N = 61.2 +/- 121.1 mL/kg vs 102.0 +/- 176.7 mL/kg, respectively, in red cell, p = 0.15; and Group H vs N = 7.9 +/- 13.7 mL/kg vs 13.2 +/- 24.5 mL/kg, respectively, in platelets, p = 0.16).

CONCLUSIONS

Patients operated on with the use of heparin-coated circuits had increased urine output during bypass and required less time postoperatively on the ventilator. These results suggest a reduction in the acute inflammatory response, capillary leakage, and overall systemic edema. We now routinely use coated circuits on all pediatric pump cases.

Congenital Heart Surgery Nomenclature and Database Project: overview and minimum dataset

The International Congenital Heart Surgery Nomenclature and Database Project was organized for the purpose of standardizing nomenclature and reporting strategies that would establish the foundations for an international database. Worldwide representatives met for a series of conferences, at which time, issues of nomenclature were discussed and debated. Authors were chosen to review the various congenital heart diagnoses and reflect the mediated debate that followed. Manuscripts were prepared that reviewed the appropriate extant nomenclature, made recommendations for an inclusive rather than an exclusive method of reporting, and determined a hierarchical database scheme that would allow several levels of reporting based on the data input. This manuscript outlines two datasets for an international congenital heart surgery database, a minimum dataset and a comprehensive dataset. The comprehensive dataset includes all the imagined variables, in a hierarchical scheme, which are detailed enough to generate risk stratification analyses. The minimum dataset will include data points that would create an essential dataset, which would be mandatory for data sharing and would lend itself to basic interpretation of trends. The minimum dataset has four drop-down menus for short lists of: (1) noncardiac abnormalities/general preoperative risk factors, (2) diagnoses, (3) procedures, and (4) complications, from which clinicians can choose for entry into the minimum dataset. There was universal agreement for these datasets and short lists by the assembled members of the Society of Thoracic Surgeons-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery. The datasets and short lists were also unanimously approved by the Congenital Heart Surgery Committee of The European Association for Cardiothoracic Surgery and adopted by the European Congenital Heart Surgeons Foundation.

Congenital Heart Surgery Nomenclature and Database Project: arrhythmias

This discussion of arrhythmia terminology attempts to classify rhythm disorders for which surgical therapy may be necessary. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery, for the purpose of establishing a unified reporting system. Efforts were made to include all relevant nomenclature categories, using synonyms where appropriate. Extant surgical ablative procedures, detailed methods of pacemaker insertion, and AICD technology are discussed. A comprehensive database set is presented that is based on a hierarchical scheme. Data are entered at various levels of complexity and detail, which can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analyses. A minimum database set is also presented, which will allow for data sharing and will lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and various risk factors are presented.

Congenital Heart Surgery Nomenclature and Database Project: atrial septal defect

The extant nomenclature for atrial septal defect (ASD) is reviewed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery. All efforts were made to include all relevant nomenclature categories using synonyms where appropriate. A comprehensive database set is presented that is based on a hierarchical scheme. Data are entered at various levels of complexity and detail that can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analyses. A minimum database set is also presented that will allow for data sharing and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and various risk factors are presented.

Congenital Heart Surgery Nomenclature and Database Project: aortopulmonary window

The extant nomenclature for aortopulmonary window (AP window) and pulmonary artery origin from ascending aorta (hemitruncus) is reviewed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery. All efforts were made to include all relevant nomenclature categories using synonyms where appropriate. A comprehensive database set is presented that is based on a hierarchical scheme. Data are entered at various levels of complexity and detail that can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analyses. A minimum database set is also presented that will allow for data sharing and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and various risk factors are presented.

Congenital Heart Surgery Nomenclature and Database Project: double outlet right ventricle

Double outlet right ventricle (DORV) is a type of ventriculoarterial connection in which both great vessels arise entirely or predominantly from the right ventricle. Although the presence of aortic-mitral discontinuity and bilateral coni are important descriptors, they should not serve as absolute prerequisites for the diagnosis of DORV. The morphology of DORV is encompassed by a careful description of the ventricular septal defect (VSD) with its relationship to the semilunar valves, the great artery relationships to each other, the coronary artery anatomy, the presence or absence of pulmonary outflow tract obstruction (POTO) and aortic outflow tract obstruction (AOTO), the tricuspid-pulmonary annular distance, and the presence or absence of associated cardiac lesions. The preferred surgical treatment involves the connection of the left ventricle to the systemic circulation by an intraventricular tunnel repair connecting the VSD to the systemic semilunar valve. This ideal surgical therapy is not always possible due to the presence of confounding anatomical barriers. A multitude of alternative surgical procedures has been devised to accommodate these more complex situations. A framework for the development of the DORV module for a pediatric cardiac surgical database is proposed.

Congenital Heart Surgery Nomenclature and Database Project: ventricular septal defect

The extant nomenclature for ventricular septal defect (VSD) is reviewed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery. All efforts were made to include all relevant nomenclature categories using synonyms where appropriate. Four basic VSD types are described: Subarterial, Perimembranous, Inlet, and Muscular. A comprehensive database set is presented which is based on a hierarchical scheme. Data are entered at various levels of complexity and detail which can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analysis. A minimum database set is also presented which will allow for data sharing and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and various risk factors are presented.

Congenital Heart Surgery Nomenclature and Database Project: atrioventricular canal defect

The extant nomenclature for atrioventricular (AV) canal/atrioventricular septal defect is reviewed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery. All efforts were made to include all relevant nomenclature categories using synonyms where appropriate. The three general categories are: partial AV canal (ostium primum defect), transitional (intermediate) AV canal, and complete AV canal. A comprehensive database set is presented that is based on a hierarchical scheme. Data are entered at various levels of complexity and detail that can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analyses. A minimum database set is also presented that will allow for data sharing and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and various risk factors are presented.

Tracheal allograft reconstruction: the total North American and worldwide pediatric experiences

BACKGROUND

We reviewed both the North American and the total worldwide pediatric experience with tracheal allograft reconstruction as treatment for patients with long segment and recurrent tracheal stenosis.

METHODS

The stenosed tracheal segment is opened to widely patent segments. The anterior cartilage is resected and the posterior trachealis muscle or tracheal wall remains. A temporary silastic intraluminal stent is placed and absorbable sutures secure the chemically preserved cadaveric trachea. After initial success with this technique in Europe, several North American centers have now performed the procedure. The cumulative North American experience includes 6 patients (3 adults and 3 children). Worldwide, more than 100 adults and 31 children, aged 5 months to 18 years, with severe long segment tracheal stenosis have undergone tracheal allograft reconstruction.

RESULTS

In North America, 5 of 6 patients have survived, with one early death due to bleeding from a tracheal-innominate artery fistula in a previously irradiated neck. Worldwide, 26 children survived (26 of 31 = 84%) with follow-up from 5 months to 14 years. Only 1 of 26 pediatric survivors (1 of 26 = 3.8%) had a tracheostomy.

CONCLUSIONS

Tracheal allograft reconstruction demonstrates encouraging short- to medium-term results for patients with complex tracheal stenosis. Allograft luminal epithelialization supports the expectation of good long-term results.

Video-assisted thoracoscopic surgery for patent ductus arteriosus in low birth weight neonates and infants

BACKGROUND

Video-assisted thoracoscopic surgery (VATS) has been assuming an expanded role in the management of cardiothoracic disease. As instrumentation and experience increase, VATS is being applied to treat smaller patients. We report our experience with 34 low birth weight infants undergoing VATS interruption of patent ductus arteriosus (PDA).

METHODS

VATS allows PDA interruption without the muscle cutting or rib spreading of a standard thoracotomy. Four small, 3-mm incisions are made along the line of a potential thoracotomy incision. Ports placed through these incisions admit endoscopic instruments, a camera, and a vascular clip applier.

RESULTS

Median age at surgery was 15.5 days (range: 1-44 days). Median weight at surgery was 930 g (range: 575-2500 g). Twenty patients weighed <1 kg, and 13 weighed <750 g. All patients had congestive heart failure and had either failed indomethacin therapy or had contraindications to indomethacin. Median surgical time was 60 minutes (range: 31-171 minutes). Echocardiography documented elimination of ductal flow in all patients. Operative mortality was zero. Four patients (4/34 = 12%) required conversion to open thoracotomy: 1 because of difficult exposure, 1 because of pulmonary dysfunction and anasarca, 1 because of a large 1-cm duct, and 1 because of coagulopathy and poor pulmonary compliance. Two patients died before discharge: 1 patient (surgical weight: 605 g) died on postoperative day 2 because of intracranial hemorrhage, and 1 patient (surgical weight: 1725 g) died on postoperative day 88 because of multiple system organ failure. Follow-up has demonstrated no PDA murmur in any patient, but echocardiography revealed trace ductal flow in 2 patients.

CONCLUSIONS

VATS offers a minimally traumatic, safe, and effective technique for PDA interruption in low birth weight neonates and infants.

Video-assisted cardioscopy for left ventricular thrombectomy in a child

Left ventricular thrombus is a complication of myocardial infarction, ventricular aneurysm, cardiomyopathy, and myocarditis. Left ventriculotomy has been the standard approach for removal of left ventricular thrombus. This approach has produced an unacceptable incidence of ventricular dysfunction, arrhythmias, and aneurysm formation. We describe a case of left ventricular thrombus with systemic embolization in a patient with myocarditis. Video-assisted cardioscopy allowed visualization and removal of the thrombus via an aortotomy, thereby avoiding a left ventriculotomy.

Transcatheter closure of an extracardiac Fontan fenestration

As the extracardiac Fontan operation evolves, a reliable method for creating and subsequently closing communications between the systemic and pulmonary venous chambers would be useful. We describe a surgical technique for creating this "fenestration" and a complementary transcatheter technique that allows safe and reliable closure of these communications regardless of size and position.