Minimal hepatic encephalopathy (MHE) in cirrhotic patients is associated with specific changes in parameters of the immune system reflecting a more pro-inflammatory environment than in patients without MHE. The aims of this work were to assess the effects of rifaximin treatment of cirrhotic patients with MHE on: (1) MHE; (2) intermediate (CD14++CD16+) pro-inflammatory monocytes; (3) expression of early activation marker CD69 in T lymphocytes; (4) autoreactive CD4+CD28− T lymphocytes; (5) differentiation of CD4+ T lymphocytes to Th follicular and Th22; (6) serum IgG levels; and (7) levels of some pro-inflammatory cytokines. These parameters were measured by immunophenotyping and cytokine profile analysis in 30 controls without liver disease, 30 cirrhotic patients without MHE and 22 patients with MHE. Patients with MHE were treated with rifaximin and the same parameters were measured at 3 and 6 months of treatment. We assessed if changes in these parameters are different in patients who improve MHE (responders) and those who remain in MHE (non-responders). Rifaximin improved MHE in 59% of patients with MHE. In these responder patients rifaximin normalized all alterations in the immune system measured while in non-responders it normalizes only IL-6, CCL20, and differentiation of T lymphocytes to Th22. Non-responder patients do not show increased expression of CD69 before treatment. Rifaximin normalizes changes in the immune system in patients who improve MHE but not in non-responders. Some alterations before treatment are different in responders and non-responders. Understanding these differences may identify predictors of the response of MHE to rifaximin.

Minimal hepatic encephalopathy (MHE) is associated with mild cognitive impairment and frailty. This study aims to identify cognitive and motor differences in cirrhotic patients with and without MHE, and the correlations between motor signs and cognitive performance. Gait, balance, hand strength and motor speed performance were evaluated in 66 cirrhotic patients (38 without and 28 with MHE, according to the Psychometric Hepatic Encephalopathy Score (PHES). Cognitive performance was measured with the Mini-Mental State Examination, Verbal Fluency Test, Aprendizaje Verbal España-Complutense Test (TAVEC), Wechsler Adult Intelligence Scale III, Hamilton Depression and Anxiety Rating Scale and Functioning Assessment Short Test (FAST). MHE patients performed worse than patients without MHE in cognitive and autonomous functioning, learning and long-term memory, and verbal fluency. The same pattern was found in gait, center of pressure movement, variability of hand strength performance and hand motor speed. In MHE patients, high correlations were found between balance and FAST test, gait velocity and verbal skills, hand strength variability and anxiety and depression, and motor speed and FAST and TAVEC. MHE patients showed worse motor and cognitive performance than patients without MHE. MHE patients could have impaired movement control expressed as bradykinesia, and this reduced motor performance could correlate with cognitive performance.

Patients with Benign prostatic hyperplasia, low urinary tract symptoms, and erectile dysfunction (BPH/LUTS-ED) present chronic inflammation. We studied in patients with BPH/LUTS-ED the effect of tadalafil treatment (5 mg/day) on changes in peripheral inflammation, cognitive function, and the auditory evoked potential, “mismatch negativity” (MMN). Nine patients with BPH/LUTS-ED and 12 controls performed psychometric tests, MMN. IL-6, IL-17, IL-18, cGMP and CD4⁺CD28⁻ autoreactive T-cells were measured in blood. Patients with BPH/LUTS-ED performed psychometric tests, MMN, and blood extraction at baseline and after tadalafil treatment. Patients with BPH/LUTS-ED showed increased CD4⁺CD28⁻ autoreactive T-cells (p < 0.05), and higher levels of pro-inflammatory interleukins IL-6 (p < 0.001), IL-17 and IL-18 (p < 0.05), compared to controls. Patients got lower scores than controls in psychometric tests assessing mental processing speed and attention (p < 0.05), and showed lower amplitude (p < 0.01) and area (p < 0.05) of MMN wave than controls. Inflammatory, psychometric and electrophysiological parameters were normalized after tadalafil treatment. In conclusion, there is a pro-inflammatory environment in blood in patients with BPH/LUTS-ED which would induce cognitive impairment and alter MMN. Phosphodiesterase-5 inhibition with tadalafil exerts anti-inflammatory effects and ameliorates cognitive function and MMN parameters. Tadalafil could be a promising candidate for chronic treatment in other inflammatory pathologies associated with mild cognitive impairment.

Patients with nonalcoholic fatty liver disease (NAFLD) may show mild cognitive impairment (MCI). The neurological functions affected remain unclear. The aims were to: (1) Characterize the neuropsychological alterations in NAFLD patients; (2) assess the prevalence of impairment of neurological functions evaluated; (3) develop a new score for sensitive and rapid MCI detection in NAFLD; (4) assess differences in MCI features between patients with nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH); and (5) compare neuropsychological alterations in NAFLD patients with cirrhotic patients with MCI. Fifty-nine NAFLD patients and 53 controls performed psychometric tests assessing different neurological functions: PHES (Psychometric Hepatic Encephalopathy Score) battery, d2, Stroop, Oral SDMT (Symbol Digit Modalities Test), Digit Span, number-letter test, and bimanual and visual-motor coordination tests. NAFLD patients show impairment in attention, mental concentration, psychomotor speed, cognitive flexibility, inhibitory mental control, and working memory. We developed a new, rapid, and sensitive score based on the most affected parameters in NAFLD patients, unveiling that 32% of NAFLD show MCI. Prevalence was similar in NAFL (36%) or NASH (27%) patients, but lower in NAFLD than in cirrhosis (65%). MCI prevalence is significant in NAFLD patients. Psychometric testing is warranted in these patients to unveil MCI and take appropriate measures to reverse and prevent its progression.

Neurofilament light chain protein (NfL) levels reflect neuronal damage in several neurological diseases and have been proposed as a possible biomarker. Plasma extracellular vesicles (EVs) could play an important role as mediators of the inflammatory changes associated with inducing minimal hepatic encephalopathy (MHE) in cirrhotic patients. This study investigated the association of NfL levels in plasma and EVs with the presence of MHE in cirrhotic patients, and with responses to rifaximin treatment. The NfL levels in plasma and EVs were assessed in 71 patients with liver cirrhosis (40 with MHE and 31 without MHE) and 26 controls. A total of 31 patients with MHE received rifaximin treatment. We examined changes in NfL levels in plasma and EVs before and after 6 months of rifaximin treatment. The NfL measures were correlated with cognitive alterations and plasma inflammatory cytokines. MHE patients showed increased plasma levels of NfL, which were reverted after rifaximin treatment in patients who responded to treatment. The NfL content in EVs also showed a reversal pattern in MHE patients treated with rifaximin. In multivariable analyses, NfL levels were independently associated with the presence of MHE. We also showed that patients with high levels of both ammonia and fractalkine had significantly higher NfL levels than patients with low levels of least one of these parameters. Rifaximin treatment in MHE patients showed promising results in improving axonal damage, suggesting that rifaximin may have therapeutic benefits against disease progression in MHE.

Ammonia is a product of amino acid metabolism that accumulates in the blood of patients with liver cirrhosis, leading to neurotoxic effects and hepatic encephalopathy (HE). HE manifestations can range from mild, subclinical disturbances in cognition, or minimal HE (mHE) to gross disorientation and coma, a condition referred to as overt HE. Many blood-based biomarkers reflecting these neurotoxic effects of ammonia and liver disease can be measured in the blood allowing the development of new biomarkers to diagnose cirrhosis patients at risk of developing HE. The effect of ammonia on the brain is modulated by severity of systemic inflammation, and both hyperammonemia and inflammation can induce oxidative stress, which may mediate the neurological alterations associated to HE. This review aims to provide the latest evidence on biomarkers of HE beyond ammonia. We present different approaches to predict overt HE based on the combination of blood ammonia with some analytical and clinical parameters. Magnetic resonance analysis of brain images could also provide sensitive diagnostic biomarkers based on neuroimaging parameters. Some reports suggest that markers of systemic inflammation, oxidative stress, and central nervous system-derived components, may serve as additional biomarkers of HE. The involvement of extracellular vesicles and microbiota in the pathophysiology of mHE and HE has recently acquired importance and it would be interesting to explore their usefulness as early biomarkers of the disease. It is important to have a biomarker or a combination of them for early diagnosis of mHE to improve its treatment and prevent progression to overt HE.