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Specific Gut and Salivary Microbiota Patterns Are Linked With Different Cognitive Testing Strategies in Minimal Hepatic Encephalopathy

Bajaj, Jasmohan S. MD1; Fagan, Andrew BS1; White, Melanie B. RN1; Wade, James B. PhD2; Hylemon, Phillip B. PhD3,4; Heuman, Douglas M. MD1; Fuchs, Michael MD1; John, Binu V. MD1; Acharya, Chathur MD1; Sikaroodi, Masoumeh PhD2; Gillevet, Patrick M. PhD2

American Journal of Gastroenterology: July 2019 - Volume 114 - Issue 7 - p 1080–1090
doi: 10.14309/ajg.0000000000000102
ARTICLE
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OBJECTIVES: Minimal hepatic encephalopathy (MHE) is epidemic in cirrhosis, but testing strategies often have poor concordance. Altered gut/salivary microbiota occur in cirrhosis and could be related to MHE. Our aim was to determine microbial signatures of individual cognitive tests and define the role of microbiota in the diagnosis of MHE.

METHODS: Outpatients with cirrhosis underwent stool collection and MHE testing with psychometric hepatic encephalopathy score (PHES), inhibitory control test, and EncephalApp Stroop. A subset provided saliva samples. Minimal hepatic encephalopathy diagnosis/concordance between tests was compared. Stool/salivary microbiota were analyzed using 16srRNA sequencing. Microbial profiles were compared between patients with/without MHE on individual tests. Logistic regression was used to evaluate clinical and microbial predictors of MHE diagnosis.

RESULTS: Two hundred forty-seven patients with cirrhosis (123 prior overt HE, MELD 13) underwent stool collection and PHES testing; 175 underwent inhibitory control test and 125 underwent Stroop testing. One hundred twelve patients also provided saliva samples. Depending on the modality, 59%–82% of patients had MHE. Intertest Kappa for MHE was 0.15–0.35. Stool and salivary microbiota profiles with MHE were different from those without MHE. Individual microbiota signatures were associated with MHE in specific modalities. However, the relative abundance of Lactobacillaceae in the stool and saliva samples was higher in MHE, regardless of the modality used, whereas autochthonous Lachnospiraceae were higher in those without MHE, especially on PHES. On logistic regression, stool and salivary Lachnospiraceae genera (Ruminococcus and Clostridium XIVb) were associated with good cognition independent of clinical variables.

DISCUSSION: Specific stool and salivary microbial signatures exist for individual cognitive testing strategies in MHE. The presence of specific taxa associated with good cognitive function regardless of modality could potentially be used to circumvent MHE testing.

1Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia;

2Division of Psychiatry, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia;

3Division of Microbiology and Immunology, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia;

4Microbiome Analysis Center, George Mason University, Manassas, Virginia.

Correspondence: Jasmohan S. Bajaj, MD. E-mail: Jasmohan.bajaj@vcuhealth.org.

SUPPLEMENTARY MATERIAL accompanies this paper at http://links.lww.com/AJG/A23

Received August 15, 2018

Accepted December 04, 2018

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INTRODUCTION

Hepatic encephalopathy (HE) is one of the leading causes of morbidity and mortality in patients with cirrhosis (1,2). The spectrum of neurocognitive impairment in cirrhosis ranges from the subtle covert HE through disorientation, stupor, and coma, known as overt HE (OHE) (2). Covert HE, which includes minimal HE (MHE), is associated with medical outcomes such as progression to OHE, hospitalizations, and death; as well as psychosocial outcomes such as impaired driving ability, a lower health-related quality of life, and socioeconomic status (3). Therefore, the diagnosis of MHE is important but is rarely made because MHE diagnostic tests are often associated with poor intertest agreement (4–7). In addition, testing strategies for MHE interrogate different brain regions and are differentially associated with ammonia and systemic inflammation (8–10).

Underlying this spectrum of cognitive impairment is an altered gut-liver-brain axis. The components of these alterations include an unfavorable gut microbiota composition, increased local and systemic inflammation, and impaired immune response (11–13). However, to date, there have been limited research studies on the association between gut microbiota profiles with differing MHE testing strategies and the potential practical use of specific microbial profiles to diagnose MHE.

Our aim was to (i) determine gut and salivary microbial profiles of patients with and without MHE based on several approved tests and (ii) define a profile of gut and salivary microbiota whose presence is associated with cognitive dysfunction in cirrhosis independent of clinical variables.

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METHODS

The overall study is a prospective enrollment of outpatients with cirrhosis who underwent cognitive testing and stool and saliva collection for characterization of the microbiota and MHE status. We enrolled outpatients with cirrhosis from hepatology clinics at the Virginia Commonwealth University and Richmond VA Medical Center after obtaining written informed consent. Patients were diagnosed with cirrhosis based on any of the following criteria: liver biopsy, transient elastography, evidence of varices, and nodular contour of liver or thrombocytopenia in a patient with chronic liver disease or frank decompensation of cirrhosis. We excluded patients with an unclear cirrhosis history; those unable to provide consent; those with grade 1 HE; those with current alcohol or illegal drug abuse, those on antipsychotics, antiseizure medication, older antidepressants, or benzodiazepine usage; those with recent transjugular intra-hepatic porto-systemic shunting (<3 months); those with recent changes in opioid medications (over the last 3 months); and those with recent (<1 month) hospitalizations. We included patients on stable selectice serotonin reuptake inhibitors or SNRI antidepressants and those on stable doses of opioid therapy (for >3 months).

Every patient was administered the mini-mental status examination, and only those with a score of ≥25 were given the specialized cognitive tests. The patients underwent testing with the following validated strategies for MHE: (i) psychometric hepatic encephalopathy score (PHES) (14), (ii) inhibitory control test (ICT) (15), and (iii) EncephalApp Stroop (16) during the same sitting in this order. We administered PHES to everyone, whereas a subset also underwent ICT and EncephalApp Stroop testing. Minimal hepatic encephalopathy was diagnosed on US-based norms (17).

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Cognitive testing details

PHES consists of 5 tests, their s.d. values are compared against healthy controls, and the total sum is added. A low total score against the reference control population indicates poor performance. EncephalApp Stroop has two sections, an easier Off state, where the subject has to recognize the color of the # signs appropriately and touch the screen at the corresponding color, and a more difficult On state, where the words meaning specific colors are presented in discordant colors. The time to complete 5 correct runs in each state is added with the total time, OffTime, OnTime, and the number of runs required to complete 5 states. A higher time required indicates poor performance. Inhibitory control test is computer based, in which subjects are shown a series of letters and are asked to respond by pressing a mouse key when an X is followed by a Y or a Y is followed by an X (alternating presentation, termed targets). Patients are instructed not to respond to X following X or Y following Y (nonalternating presentation, termed lures). High lure and low target response indicate poor psychometric performance. The ICT is administered as a practice test, followed by a series of 6 similar 2-minute runs, separated by breaks to allow the subjects to rest. There are a total of 212 targets and 40 lures scattered throughout the test. Weighted lures are lures divided by the square of target accuracy/100 (18). Although all patients underwent PHES, the ICT and EncephalApp Stroop administration varied based on availability of the test and logistics at the time of the sample collection and exclusions for the test including red-green color blindness. None of the patients were systematically excluded from taking any specific cognitive test. All patients also underwent a dietary history with recall over the last 3 days, focusing on caloric intake, protein intake, and the intake of meat vs vegetarian diets.

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Microbiota analysis

In addition, patients provided a stool sample and a subset also provided saliva samples using published techniques on the same day (19). 16srRNA microbiota analysis was performed using Multitag sequencing on an Ion Torrent personal genome machine, as previously published (20). The main objectives were to determine the microbial taxa that differentiated between patients who had MHE on individual modalities compared with the rest in the entire group and the subset without prior OHE. All analyses were performed separately for stool and salivary microbiota. We used linear discriminant analysis effect size (LEFSe) to determine the taxa that differentiated the groups (21).

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Model building to predict cognitive impairment with and without clinical variables

Ultimately, microbial taxa that were significantly different on LEFSe between the groups were then introduced into a logistic regression model with clinical variables of defining cognitive impairment. Variables significant at P < 0.20 on univariate analysis were introduced into the final models, and backward logistic regression models were used to predict specific cognitive impairments.

The clinical variables used were age, sex, education, prior OHE (for the entire cirrhosis group), proton pump inhibitor (PPI) use, and model for end-stage liver disease (MELD) score. In the no-OHE group, all the above clinical variables were input apart from prior OHE. Microbiota families were input one phylum at a time for data reduction, and specific families with P < 0.20 were input with the clinical variables for the final model.

Last, to interrogate the specific taxa at a deeper level, for bacterial families that emerged significant in the prediction of the logistic regression models, we further analyzed them at the genus level to determine the specific genera associated with specific cognitive impairments or with normal cognitive function.

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RESULTS

We enrolled 267 patients with cirrhosis, all of whom underwent PHES testing and stool collection. Of these patients, 123 had prior HE (118 on lactulose and 77 on rifaximin). One hundred seventy-five patients underwent additional ICT, and 125 also underwent EncephalApp Stroop tests. A subset of patients (n = 112) also provided saliva samples. The details of MHE diagnosis using the individual modalities in patients who underwent stool and saliva collection are shown in Figure 1a, b.

Figure 1

Figure 1

As shown in Table 1, patients with OHE were more likely to be men, be on PPI, and have a higher MELD score and worse cognitive performance than patients without prior OHE. Most patients with prior OHE were on lactulose and rifaximin, and none of the patients without prior OHE were on any of these medications. Details of patients who provided saliva samples are shown in Table 2.

Table 1

Table 1

Table 2

Table 2

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MHE diagnosis

In the entire group, using PHES, 145 (54%) patients had MHE; in patients who underwent Stroop testing (total n = 125), 102 (81%) had MHE; and in patients administered the ICT (n = 175), 115 (65%) had MHE (Table 3). Among the 125 patients who underwent both Stroop and PHES tests, 43 (34%) were discordant (P < 0.0001, χ2). In the 175 patients who underwent both ICT and PHES, 70 (39%) were discordant (P = 0.001), and in the 99 patients who underwent Stroop and ICT, discordant results were seen in 29 (29%, P = 0.01). There were no significant demographic or cirrhosis-related differences between patients who received 1, 2, or all 3 tests (see Tables S1 and S2, Supplementary Digital Content 1, http://links.lww.com/AJG/A23 for information about patients who provided stool and saliva samples, respectively). The reasons for patients not being administered the Stroop were largely related to the availability of the test, which was developed after ICT and PHES and red-green color blindness in potential patients, whereas the reasons for not being able to administer ICT were logistical, related to time and availability of the program at the time of the stool, saliva, and serum collection.

Table 3

Table 3

In patients without prior OHE who provided stool samples, there were 63 (of 144, 44%) who were positive for MHE on PHES, 54 (of 87, 62%) who were positive for ICT, and 35 (of 49, 71%) who were positive for Stroop MHE. Of these patients, only 61 patients were MHE positive for both PHES and Stroop (Table 4). When MHE positivity was compared, 83 (58%) were discordant between ICT and PHES, 69 (47%) were discordant between Stroop and PHES, and 54 (38%) were discordant between ICT and Stroop.

Table 4

Table 4

Ultimately, there was poor kappa agreement between the modalities (PHES vs ICT = 0.15, PHES vs Stroop = 0.35, and Stroop vs ICT = 0.20) for the diagnosis in patients who had more than one testing modality used.

Dietary analysis showed that all patients were nonvegetarian and largely followed a Western diet. The mean ± s.d. daily caloric intake and proportion of calories from protein over the last 3 days on dietary recall were statistically similar between those with and without MHE on PHES (no-MHE 2,318 ± 230 Kcal vs 2,295 ± 429 Kcal, P = 0.62 and 28% ± 10% vs 26% ± 13% protein, P = 0.19).

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Microbiota changes

We obtained stool samples from all 267 patients, whereas saliva samples were obtained from 122 patients (49 prior OHE and 73 without OHE). The entire group was first evaluated from the salivary and stool microbiota perspective based on MHE on the 3 individual modalities.

We then evaluated MHE on PHES in patients without prior OHE on stool and same for ICT and Stroop. Shannon diversity indexes are shown in Table 5.

Table 5

Table 5

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LEFSe in the entire group

Stool changes.

Using PHES as the definition of MHE, there was a higher relative abundance of Lactobacillales and Micrococcaceae and it was lower for Lachnospiraceae, Clostridiales Incertae Sedis XI and XIII, and Pasteurellaceae in those with MHE (Figure 2a). Similarly, using ICT, there was a higher relative abundance of Enterobacteriaceae, Streptococcaceae, Micrococcaceae, and Eubacteriaceae and it was lower for Bacteroidaceae in those with MHE. When Stroop was used, the relative abundance of Lactobacillales was higher and that of Eubacteriaceae, Telmatobacter, and taxa belonging to Proteobacteria in those with MHE was lower.

Figure 2

Figure 2

Figure 2

Figure 2

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Salivary changes.

In patients with MHE on PHES, the relative abundance of salivary Lactobacillaceae, Streptococcaceae, Sutterellaceae, and Clostridiaceae was higher, whereas it was lower for Prevotellaceae, Saccharibacteria, Fusobacteriaceae, and Eubacteriaceae (Figure 2c). Using ICT, again there was a higher relative abundance of Lactobacillaceae and it was lower for Saccharibacteria and constituents of Proteobacteria in those with MHE. On Stroop, in patients with MHE, again a higher relative abundance of Lactobacillaceae and Streptococcaceae and a lower relative abundance of Proteobacteria, Fusobacteria, and Prevotellaceae were observed.

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LEFSe in patients without prior OHE

Stool changes.

Patients with MHE on PHES had a higher Lactobacillaceae and Micrococcaceae and a lower relative abundance of Lachnospiraceae, Acidaminococcaceae, and Cyanobacteria compared with those without MHE (Figure 2b). Using ICT, there were again higher Lactobacillaceae, Enterobacteriaceae, and Streptococcaceae and lower Bacteroidaceae and Peptococcaceae in those with MHE. When Stroop was used, there was a higher relative abundance of Lactobacillaceae, Bifidobacteriaceae, Micrococcaceae, and Gammaproteobacteria and a lower relative abundance of Cyanobacteria and Clostridiales cluster XIII in those with MHE.

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Salivary changes.

PHES-associated MHE was associated with higher relative abundance of Lactobacillaceae and lower Proteobacteria, Chloroplast and several members of the Firmicutes phylum (Figure 2d). Using Stroop, there was a higher relative abundance of Lactobacillaceae and Streptococcaceae and a lower relative abundance of Proteobacteria in those with MHE. Patients with MHE on ICT had higher Veillonellaceae and lower Proteobacteria, Staphylococcaceae, and Acetobacteraceae compared with those without MHE.

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Logistic regression

As shown in Table 6, several microbial families in the stool and saliva samples were associated with MHE independent of the input clinical variables. Specifically, Lachnospiraceae were associated with protection from MHE on PHES and Stroop, whereas Veillonellaceae were associated with ICT-associated MHE. In the saliva samples, Streptococcaceae and Coriobacteriaceae were associated with MHE on the 3 modalities, whereas Clostridiales cluster XI and Prevotellaceae were associated with protection against MHE.

Table 6

Table 6

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Genus-level changes in taxa found on logistic regression.

In the stool samples of all patients, the specific genera in Lachnospiraceae associated with protection from MHE, as assessed by PHES, were Blautia, Dorea, Roseburia, Clostridium XIVb, Robinsoniella, Coprococcus, and Ruminococcus. Using ICT, Ruminococcus, Clostridium XIVb, and Cellulosilyticum were found, and using Stroop, Clostridium XIVb and Lachnospira were found. Only in the stool samples of patients without prior OHE, the similar Lachnospiraceae genera were higher in those without MHE based on the PHES and Stroop assessment, whereas Veillonella was higher in ICT-associated MHE.

In saliva samples, Streptococcus was associated with MHE determined by the Stroop and PHES assessment in the entire group. In those without prior OHE, Lactobacillus and Paralactobacillus were higher in MHE determined by PHES and Prevotella was higher in those with MHE based on Stroop performance. In those without MHE determined by ICT, Abiotrophia from Aerococcaceae and Clostridium XIVb of Lachnospiraceae were in greater relative abundance.

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DISCUSSION

The current study results demonstrate that patients with cirrhosis and MHE defined according to specific cognitive assessment strategies have unique microbial signatures in the stool and saliva samples. These microbial changes are associated with the diagnosis of MHE independent of clinical criteria, and the presence of specific bacterial taxa is indicative of normal cognition in this population.

Patients with cirrhosis and MHE suffer from a poor health-related quality of life, a greater likelihood to progress to OHE, and increased need for hospitalization and have a worse survival compared with those without MHE (22,23). It is often difficult to diagnose these patients because of logistic concerns related to the available cognitive assessment methodologies including the relatively poor diagnostic agreement between these tests (24). Consistent with the literature, we found a similar discordance between PHES, Stroop, and ICT in our patient population (4–6). These tests interrogate different parts of the brain with psychomotor speed being a common denominator between the tests. The psychometric hepatic encephalopathy score places a strong demand on a subject's visual-motor coordination and abstraction ability (14). In contrast to the PHES, the EncephalApp Stroop emphasizes cognitive flexibility, with the ICT assessing working memory and response inhibition (25,26). Given that each of the 3 cognitive methods used in this study emphasizes differing cognitive skill sets, it is not surprising that MHE classification, based on the individual test results compared with locally derived norms, would vary (27). However, the specific underlying factors associated with these neurobehavioral changes in MHE patients remain uncertain.

An altered gut-liver-brain axis is believed to be a central pathogenic factor accounting for the spectrum of cognitive impairment in cirrhosis, and indeed, most HE-related therapies are focused on the gut (2,28). Therefore, the changes in brain function underlying impaired performances on these tests could be related to alterations in gut microbiota. Changes in microbiota in cirrhosis have been shown in the stool, intestinal mucosa, serum, and saliva samples (7,29–32). This is likely related to changes in underlying immune function in cirrhosis, which allows these alterations in microbiota to occur (13,33). Patients with cirrhosis, especially those with advanced cirrhosis and OHE, have lower relative abundance of autochthonous bacterial taxa and higher potentially pathogenic ones (11). These are also associated with salivary bacterial changes (19). Therefore, specific microbial signatures that were found in our study that are linked to specific microbiota are intriguing.

We found that Shannon diversity indexes varied according to the test used and patients who were positive on PHES and Stroop, but not ICT, had lower diversity in the stool and salivary microbiota. This trend continued to a large extent in those without prior OHE and was despite similar dietary practices between the groups with and without MHE (34). This could be a function of liver disease severity as patients with MHE on PHES in the entire group had a higher MELD score compared with the rest. However, there are likely other factors at play because the MELD score was similar in patients without prior OHE who were positive on PHES and yet their diversity was lower. Nevertheless, the basic concept of diversity of the microbiota already showed differentiating features between the three modes of MHE diagnosis.

Specific bacterial taxa in the stool and saliva differentiated between patients with and without MHE, but Lactobacillaceae were overrepresented in the MHE group (30). In the stool samples, Lactobacillaceae are associated with the use of lactulose, which was prescribed to most of the prior OHE patients. However, we found a higher relative abundance of Lactobacillaceae in the stool of patients without prior OHE who had MHE and in the saliva as well. Because patients without OHE were not treated with lactulose and were not on specific probiotics, it is highly unlikely that this was an iatrogenic change. In previous studies based on 16srRNA and metagenomic sequencing, Lactobacillaceae have been associated with more advanced liver disease and to be linked with ammonia-associated changes on brain MRI (9,35). In animal models of cirrhosis, lactic acid has been associated with cerebral edema (36). In the logistic regression, both Lactobacillus and Paralactobacillus were found to be higher in the saliva of patients with MHE determined by PHES. The intriguing aspect is that this increase in relative abundance of Lactobacillaceae was greater in the group without prior OHE and was found to be higher in patients with MHE, regardless of the modality used. Although there have been studies evaluating the role of Lactobacillus-only probiotics in cirrhosis, they have not consistently resulted in cognitive improvement (37). Also, there are several species within Lactobacillus that are associated with pathogenic outcomes in addition to being probiotic in nature (38). Lactobacillus spp have also been associated with superinfections with other organisms and can increase after immunosuppressive therapy (39,40). Although Lactobacillaceae changes did not remain significant after logistic regression, these relatively consistent differences are intriguing and further analyses of the role of these microbes in gut-brain axis alterations in cirrhosis are needed.

On the other hand, genera belonging to Lachnospiraceae were present in greater relative abundance in patients without MHE in the stool in those with PHES and Stroop, even on logistic regression independent of clinical factors. Specific genera included Blautia, Roseburia, Clostridium XIVb, and Ruminococcus. These taxa are associated with intestinal barrier integrity and short-chain fatty acid production and are usually found in higher relative abundances in patients with good cognition in previous studies (31,41,42). Specific Clostridia are responsible for synthesizing the neuroprotective 3-indolepropionic acid as well (43). The interesting aspect is that the presence of these taxa, especially Clostridium XIVb and Ruminococcus, indicates better cognitive function on all 3 testing strategies and could be a method to exclude significant cognitive dysfunction in patients with cirrhosis. However, further prospective studies are needed to confirm these findings in other populations.

In the saliva, apart from the Lactobacillaceae changes, there was a higher relative abundance of Veillonella and Streptococcus in patients with cognitive impairment, even on logistic regression. Streptococcaceae are associated with production of ammonia through urease activity, which could be associated with the cognitive dysfunction, and were found in greater relative abundance when the entire group was studied rather than those without OHE (44). Of interest, these oral-origin taxa were not consistently higher in the stool of patients with MHE, likely because of the similar proportion of PPI use across the groups with and without MHE (45).

The association of altered biological processes in the determination of brain dysfunction in cirrhosis is relevant from a clinical and pathophysiological perspective. In previous studies, PHES and electroencephalogram have been separately linked with systemic inflammation and ammonia metabolism in patients with cirrhosis (8). Both modalities were independently associated with poor outcomes, regardless of the pathogenesis. There is published evidence that changes in microbial composition can be associated with hospitalizations, HE episodes, and death and recovery of brain function posttransplant (46–49). Previous reports have also focused differentially on specific gut microbiota and associated ammonia-related and inflammation-related consequences on brain magnetic resonance imaging in cirrhosis (9). A previous study from China has found a higher stool Streptococcaceae relative abundance linked with ammonia in patients with cognitive impairment on paper pencil tests (44). The current results extend these results further by including the entire spectrum of cognitive dysfunction, using multiple methods of cognitive impairment to define MHE and by using salivary microbiota.

Our study is limited by its cross-sectional design and by relatively small numbers of patients who underwent Stroop compared with other modalities. We also had a relatively smaller number of salivary microbiota analyses compared with the stool. Also because of logistic concerns, not all patients underwent all MHE testing modalities or saliva collection. We did not focus on differentiating prior OHE compared with those without prior OHE in this analysis because those data have been published extensively and are usually confounded by disease severity and therapeutic options for OHE that can affect the microbiota.

We conclude that there is a specific microbial signature in the stool and salivary microbiota that is associated with individual cognitive impairment in patients with cirrhosis. These microbial changes are associated with cognitive impairment independent of clinical factors. Specific microbial taxa are associated with good cognitive function, regardless of MHE testing modality, and could potentially be used to circumvent MHE testing as a beneficial biomarker of a healthy gut-liver-brain axis in cirrhosis.

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CONFLICTS OF INTEREST

Guarantor of the article: Jasmohan S. Bajaj, MD.

Specific author contributions: J.S.B. conceptualized the study; M.B.W., A.F., and C.A. helped with cognitive testing and recruitment; D.M.H., M.F., and B.V.J. helped with recruitment; J.B.W. and P.B.H. were involved in drafting and critical appraisal; and P.M.G. and M.S. were involved in microbiota and bio-informatics analysis.

Financial support: Partly supported by R21TR0202024 and VA Merit Review I0CX001076 and McGuire Research Institute Funds to JSB. The sponsors had no role in study design, data analysis, or decision to publish.

Potential competing interests: None.

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Study Highlights

WHAT IS KNOWN

  • ✓ Minimal hepatic encephalopathy is an epidemic neurocognitive disorder in cirrhosis with serious medical and psychosocial consequences.
  • ✓ Several tests, such as PHES, ICT, and EncephalApp Stroop, used to diagnose MHE have poor concordance, which makes it difficult to diagnose MHE routinely.
  • ✓ Patients with cirrhosis have an altered gut-brain axis, but the individual microbial signatures related to specific MHE tests and potential use of microbiota to evaluate normal cognition are uncertain.
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WHAT IS NEW HERE

  • ✓ In outpatients with cirrhosis, there were different microbial signatures in stool and saliva samples of patients who tested positive for MHE based on individual modalities.
  • ✓ Lactobacillaceae were higher in relative abundance in patients with MHE, regardless of the modality used in the stool and saliva samples.
  • ✓ Specific genera belonging to autochthonous Lachnospiraceae were associated with normal cognition independent of clinical variables, regardless of MHE testing modality, and could potentially be used as a beneficial biomarker of a healthy gut-liver-brain axis in cirrhosis.
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