Alteraciones neurológicas en pacientes cirróticos con Encefalopatía Hepática Mínima. Implicación de la inflamación y el estrés oxidativo

La encefalopatía hepática (EH) es un síndrome neuropsiquiátrico complejo secundario a una cirrosis hepática, mostrando una incidencia importante (33-50%). Existe una fase subclínica llamada Encefalopatía Hepática Mínima (EHM) en la cual el paciente no muestra síntomas evidentes de EH pero sí que tiene alteraciones cognitivas y motoras y son pacientes con un potencial riesgo de ingreso hospitalario, debido al deterioro cognitivo. Para el diagnóstico de la EHM se utiliza como ‘gold standard’ una batería de tests psicométricos llamada PHES (Psycometric Hepatic Encephalopathy Score). Se sabe que uno de los principales factores que contribuyen al desarrollo de la EHM son el amonio y la inflamación. El objetivo principal de esta tesis es, por un lado utilizar tests psicométricos que permitan un estudio más fino de cada alteración neurológica específica que la que realiza el PHES y, realizar un estudio sobre la presencia de estrés oxidativo/nitrosativo en la EHM y la implicación de éste y de la inflamación en el deterioro cognitivo. Para ello se han evaluado diferentes alteraciones cognitivas (atención selectiva, atención selectiva/sostenida, memoria de trabajo, velocidad de procesamiento mental, concentración) y motoras (coordinación bimanual y visuomotora) mediante tests específicos para cada una de éstas y, diferentes parámetros en sangre indicadores de estrés oxidativo e inflamación, correlacionándose entre sí con el fin de determinar la posible implicación del estrés oxidativo e inflamción en el deterioro cognitivo en la encefalopatía hepática mínima.Hepatic encephalopathy (HE) is a complex neuropsychiatric syndrome secondary to liver cirrhosis, showing a significant incidence (33-50%). There is a subclinical stage called Minimal Hepatic Encephalopathy (MHE) in which the patient shows no obvious symptoms of HE but does shows cognitive and motor impairment and a potential risk of hospitalization due to cognitive impairment. The method of diagnosis of MHE used as a 'gold standard' consists in a battery of psychometric tests called PHES (Psycometric Hepatic Encephalopathy Score). It is known that one of the main factors contributing to the development of MHE are hyperammonia and inflammation. The main objective of this thesis is use psychometric tests that allow a more sensible study of each specific neurological disorder that PHES and a study on the presence of oxidative/nitrosative stress in MHE and study involvement of this and inflammation in cognitive impairment. This has been evaluated different cognitive disorders (selective attention, selective attention/sustained, working memory, mental processing speed, concentration) and motor (bimanual and visuomotor coordination) through specific tests for each of these alterations and different blood parameters indicators of oxidative stress and inflammation, correlated with each other in order to determine the possible involvement of oxidative stress and inflammation in cognitive impairment in minimal hepatic encephalopathy

Non invasive blood flow measurement in cerebellum detects minimal hepatic encephalopathy earlier than psychometric tests

AIM: To assess whether non invasive blood flow measurement by arterial spin labeling in several brain regions detects minimal hepatic encephalopathy.METHODS: Blood flow (BF) was analyzed by arterial spin labeling (ASL) in different brain areas of 14 controls, 24 cirrhotic patients without and 16 cirrhotic patients with minimal hepatic encephalopathy (MHE). Images were collected using a 3 Tesla MR scanner (Achieva 3T-TX, Philips, Netherlands). Pulsed ASL was performed. Patients showing MHE were detected using the battery Psychometric Hepatic Encephalopathy Score (PHES) consisting of five tests. Different cognitive and motor functions were also assessed: alterations in selective attention were evaluated using the Stroop test. Patients and controls also performed visuo-motor and bimanual coordination tests. Several biochemical parameters were measured: serum pro-inflammatory interleukins (IL-6 and IL-18), 3-nitrotyrosine, cGMP and nitrates+nitrites in plasma, and blood ammonia. Bivariate correlations were evaluated.RESULTS: In patients with MHE, BF was increased in cerebellar hemisphere (P = 0.03) and vermis (P = 0.012) and reduced in occipital lobe (P = 0.017). BF in cerebellar hemisphere was also increased in patients without MHE (P = 0.02). Bimanual coordination was impaired in patients without MHE (P = 0.05) and much more in patients with MHE (P < 0.0001). Visuo-motor coordination was impaired only in patients with MHE (P < 0.0001). Attention was slightly affected in patients without MHE and more strongly in patients with MHE (P < 0.0001). BF in cerebellar hemisphere and vermis correlated with performance in most tests of PHES [(number connection tests A (NCT-A), B (NCT-B)and line tracing test] and in the congruent task of Stroop test. BF in frontal lobe correlated with NCT-A. Performance in bimanual and visuomotor coordination tests correlated only with BF in cerebellar hemisphere. BF in occipital lobe correlates with performance in the PHES battery and with CFF. BF in cerebellar hemisphere correlates with plasma cGMP and nitric oxide (NO) metabolites. BF in vermis cerebellar also correlates with NO metabolites and with 3-nitrotyrosine. IL-18 in plasma correlates with BF in thalamus and occipital lobe.CONCLUSION: Non invasive BF determination in cerebellum using ASL may detect MHE earlier than the PHES. Altered NO-cGMP pathway seems to be associated to altered BF in cerebellum

The PHES battery does not detect all cirrhotic patients with early neurological deficits, which are different in different patients.

BACKGROUND AND AIMS:The psychometric hepatic encephalopathy score (PHES) is the "gold standard" for minimal hepatic encephalopathy (MHE) diagnosis. Some reports suggest that some cirrhotic patients "without" MHE according to PHES show neurological deficits and other reports that neurological alterations are not homogeneous in all cirrhotic patients. This work aimed to assess whether: 1) a relevant proportion of cirrhotic patients show neurological deficits not detected by PHES; 2) cirrhotic patients with mild neurological deficits are a homogeneous population or may be classified in sub-groups according to specific deficits. METHODS:Cirrhotic patients "without" (n = 56) or "with" MHE (n = 41) according to PHES and controls (n = 52) performed psychometric tests assessing attention, concentration, mental processing speed, working memory and bimanual and visuomotor coordination. Heterogeneity of neurological alterations was analysed using Hierarchical Clustering Analysis. RESULTS:PHES classified as "with" MHE 42% of patients. Around 40% of patients "without" MHE according to PHES fail two psychometric tests. Oral SDMT, d2, bimanual and visuo-motor coordination tests are failed by 54, 51, 51 and 43% of patients, respectively. The earliest neurological alterations are different for different patients. Hierarchical clustering analysis shows that patients "without" MHE according to PHES may be classified in clusters according to the tests failed. In some patients coordination impairment appear before cognitive impairment while in others concentration and attention deficits appear before. CONCLUSIONS:PHES is not sensitive enough to detect early neurological alterations in a relevant proportion of cirrhotic patients. Oral SDMT, d2 and bimanual and visuo-motor coordination tests are more sensitive. The earliest neurological alterations are different in different cirrhotic patients. These data also have relevant clinical implications. Patients classified as "without MHE" by PHES belonging to clusters 3 and 4 in our study have a high risk of suffering clinical complications, including overt HE and must be diagnosed and clinically followed

Mild Cognitive Impairment Is Associated with Enhanced Activation of Th17 Lymphocytes in Non-Alcoholic Fatty Liver Disease

Patients with nonalcoholic fatty liver disease (NAFLD) may show mild cognitive impairment (MCI). The mechanisms involved remain unclear. The plasma concentrations of several cytokines and chemokines were measured in 71 NAFLD patients (20 with and 51 without MCI) and 61 controls. Characterization and activation of leukocyte populations and CD4+ sub-populations were carried out and analyzed by flow cytometry. We analyzed the cytokines released from CD4+ cell cultures and the mRNA expression of transcription factors and receptors in peripheral blood mononuclear cells. The appearance of MCI in NAFLD patients was associated with increased activation of CD4+ T lymphocytes, mainly of the Th17 subtype, increased plasma levels of pro-inflammatory and anti-inflammatory cytokines such as IL-17A, IL-23, IL-21, IL-22, IL-6, INF-γ, and IL-13, and higher expression of the CCR2 receptor. Constitutive expression of IL-17 was found in cultures of CD4+ cells from MCI patients, reflecting Th17 activation. High IL-13 plasma levels were predictive of MCI and could reflect a compensatory anti-inflammatory response to the increased expression of pro-inflammatory cytokines. This study identified some specific alterations of the immune system associated with the appearance of neurological alterations in MCI patients with NAFLD that could be the basis to improve and restore cognitive functions and quality of life in these patients

Dendrogram showing the clustering of all individuals in main groups and sub-groups.

<p>All subjects included in the study have been arranged according to the similarity-dissimilarity of their performance in the combination of tests indicated using hierarchical clustering analysis. This analysis provides clusters including subjects more closely related between them than subjects assigned to a different cluster. These clusters are visualized in the dendrogram shown. The first column shows the number identifying each subject, which have been coloured according to their classification by the PHES: control (black), without MHE (red) or with MHE (green). These colours are repeated in the second column to facilitate its identification. The tests failed by each individual are indicated by blue colour in the corresponding box. The following tests have been included: PHES, critical flicker frequency (CFF), the congruent, neutral and incongruent tasks of the Stroop test, Bimanual and visuo-motor coordination, d2 test, TOT: total correctly processed and d2-CON: concentration, measured with the d2 test; Oral SDMT test, Digit Span and Letter-number test.</p

Performance in psychometric tests.

<p>Performance in psychometric tests.</p

Composition of the different groups and etiology of liver disease.

<p>Composition of the different groups and etiology of liver disease.</p

Performance in the PHES and in each of its tests.

<p>Performance in the PHES and in each of its tests.</p