Inhibition of inflammation is not enough for recovery of cognitive impairment in hepatic encephalopathy: Effects of minocycline and ibuprofen

Correlation of ammonia and blood laboratory parameters with hepatic encephalopathy: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

Emerging research suggests that hyperammonemia may enhance the probability of hepatic encephalopathy (HE), a condition associated with elevated levels of circulating ammonia in patients with cirrhosis. However, some studies indicate that blood ammonia levels may not consistently correlate with the severity of HE, highlighting the complex pathophysiology of this condition.

METHODS

A systematic review and meta-analysis through PubMed, Scopus, Embase, Web of Science, and Virtual Health Library were conducted to address this complexity, analyzing and comparing published data on various laboratory parameters, including circulating ammonia, blood creatinine, albumin, sodium, and inflammation markers in cirrhotic patients, both with and without HE.

RESULTS

This comprehensive review, which included 81 studies from five reputable databases until June 2024, revealed a significant increase in circulating ammonia levels in cirrhotic patients with HE, particularly those with overt HE. Notably, significant alterations were observed in the circulating creatinine, albumin, sodium, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNFα) in HE patients.

CONCLUSIONS

These findings suggest an association between ammonia and HE and underscore the importance of considering other blood parameters such as creatinine, albumin, sodium, and pro-inflammatory cytokines when devising new treatment strategies for HE.

Combination Therapy with Platelet-Rich Plasma and Epidermal Neural Crest Stem Cells Increases Treatment Efficacy in Vascular Dementia

This study aimed to evaluate the efficacy and treatment mechanism of platelet-rich plasma (PRP) and neural crest-derived epidermal stem cells (ESCs) in their administration alone and combination in vascular dementia (VaD) model by two-vessel occlusion (2VO). Methods. Sixty-six rats were divided into six groups: the control, sham, 2VO + vehicle, 2VO + PRP, 2VO + ESC, and 2VO + ESC + PRP. The treated groups received 1 million cells on days 4, 14, and 21 with or without 500 µl PRP (twice a week) after 2VO. The memory performance and anxiety were evaluated by behavioral tests including open field, passive avoidance, and Morris water maze. The basal-synaptic transmission (BST) and long-term potentiation (LTP) were assessed through field-potential recordings of the CA1. The mRNA expression levels of IGF-1, TGF-β1, PSD-95, and GSk-3β were measured in the rat hippocampus by quantitative reverse transcription polymerase chain reaction. Results. The results demonstrated impaired learning, memory, and synaptic plasticity in the 2VO rats, along with a significant decrease in the expression of IGF-1, TGF-β1, PSD-95, and upregulation of GSK-3β. Treatment with ESC alone and ESC + PRP showed similar improvements in spatial memory and LTP induction, with associated upregulation of PSD-95 and downregulation of GSK-3β. However, only the ESC + PRP group showed recovery in BST. Furthermore, combination therapy was more effective than PRP monotherapy for LTP and memory. Conclusions. The transplantation of ESC showed better effects than PRP alone, and combination therapy increased the treatment efficacy with the recovery of BST. This finding may be a clue for the combination therapy of ESC and PRP for VaD.

Combined use of hair follicle stem cells and CEPO (carbamylated erythropoietin)-Fc in a rat model of chronic cerebral hypoperfusion: A behavioral, electrophysiological, and molecular study

BACKGROUND

In dementia, synaptic dysfunction appears before neuronal loss. Stem cell therapy could potentially provide a promising strategy for the treatment of dementia models. The carbamylated erythropoietin fusion protein (CEPO-Fc) has shown synaptotrophic effects. This study aimed to determine the efficiency of the combined use of hair follicle stem cells (HFSC) and CEPO-Fc in the basal synaptic transmission (BST) and long-term plasticity (LTP) of chronic cerebral hypoperfusion (CCH) rats.

METHODS

We divided 64 adult rats into control, sham, CCH+vehicle, CCH+CEPO, CCH+HFSC, and CCH+HFSC+CEPO groups. The CEPO-Fc was injected three times/week for 30 days. HFSC transplantation was done on days 4, 14, and 21 after surgery. The Morris water maze test and passive avoidance were used to assess memory. BST and LTP were assessed by a field-potential recording of the CA1 region. The hippocampal mRNA expression of IGF-1, TGF-β1, β1-Catenine, NR2B, PSD-95, and GSk-3β was evaluated by quantitative RT-PCR.

RESULTS

Following combination therapy, spatial memory retention, and BST showed significant improvement relative to HFSC and CEPO-Fc groups. These effects were also confirmed by recovered mRNA expression of β1-catenin, TGF-β1, and NR2B. GSK-3β expression was downregulated in all treatment groups. The upregulated PSD-95 was identified in HFSC and combination groups compared to the vehicle group.

CONCLUSIONS

These findings indicate that the combined use of HFSC and CEPO-Fc may be more advantageous for treating memory disruption in the CCH model than CEPO-Fc or HFSC alone. This type of combination therapy may hopefully lead to a new approach to treatment for dementia.

Effect of Berberine against Cognitive Deficits in Rat Model of Thioacetamide-Induced Liver Cirrhosis and Hepatic Encephalopathy (Behavioral, Biochemical, Molecular and Histological Evaluations)

BACKGROUND

Liver cirrhosis (LC) is one of the chronic liver diseases with high disability and mortality accompanying hepatic encephalopathy (HE) followed by cognitive dysfunctions. In this work, the effect of berberine (Ber) on spatial cognition was studied in a rat model of LC induced by thioacetamide (TAA).

MATERIALS AND METHODS

Male Wistar rats (200-250 g) were divided into six groups: (1) control; (2) TAA, 200 mg/kg/day, i.p.; (3-5) TAA + Ber; received Ber (10, 30, and 60 mg/kg, i.p., daily after last TAA injection); (6) Dizocilpine (MK-801) + TAA, received MK-801 (2 mg/kg/day, i.p.) 30 m before TAA injection. The spatial memory, BBB permeability, brain edema, liver enzymes, urea, serum and brain total bilirubin, oxidative stress and cytokine markers in the hippocampus were measured. Furthermore, a histological examination of the hippocampus was carried out.

RESULTS

The BBB permeability, brain edema, liver enzymes, urea, total bilirubin levels in serum and hippocampal MDA and TNF-α increased significantly after TAA injection (p < 0.001); the spatial memory was impaired (p < 0.001), and hippocampal IL-10 decreased (p < 0.001). Ber reversed all the above parameters significantly (p < 0.05, p < 0.01 and p < 0.001). MK-801 prevented the development of LC via TAA (p < 0.001).

CONCLUSION

Results showed that Ber improves spatial learning and memory in TAA-induced LC by improving the BBB function, oxidative stress and neuroinflammation. Ber might be a promising therapeutic agent for cognitive improvement in LC.

Chronic exposure to 2.45 GHz microwave radiation improves cognition and synaptic plasticity impairment in vascular dementia model

Purpose: In this study, we evaluated the effects of 2.45 GHz microwave radiation on cognitive dysfunction induced by vascular dementia (VaD).Methods: The VaD was induced by bilateral-common carotid occlusion (2-VO). The rats were divided into 4 groups including: control (n = 6), sham (n = 6), 2-VO (n = 8), and 2-VO + Wi-Fi (n = 10) groups. Wi-Fi modem centrally located at the distance of 25 cm from the animal's cages and the animals were continuously exposed to Wi-Fi signal while they freely moved in the cage (2 h/day for forty-five days). Therefore, the power density (PD) and specific absorption rate value (SAR) decreased at a distance of 25 to 60 cm (PD = 0.018 to 0.0032 mW/cm², SAR = 0.0346 to 0.0060 W/Kg). The learning, memory, and hippocampal synaptic-plasticity were evaluated by radial arm maze (RAM), passive avoidance (PA), and field-potential recording respectively. The number of hippocampal CA1 cells was also assessed by giemsa staining.Results: Our results showed that VaD model led to impairment in the spatial learning and memory performance in RAM and PA that were associated with long-term potentiation (LTP) impairment, decrease of basal-synaptic transmission (BST), increase of GABA transmission, and decline of neurotransmitter release-probability as well as hippocampal cell loss. Notably, chronic Wi-Fi exposure significantly recovered the learning-memory performance, LTP induction, and cell loss without any effect on BST.Conclusions: The LTP recovery by Wi-Fi in the 2-VO rats was probably related to significant increases in the hippocampal CA1 neuronal density, partial recovery of neurotransmitter release probability, and reduction of GABA transmissiSon as evident by rescue of paired-pulse ratio 10 ms.

Targeting neuroinflammation as a preventive and therapeutic approach for perioperative neurocognitive disorders

Perioperative neurocognitive disorders (PND) is a common postoperative complication associated with regional or general anesthesia and surgery. Growing evidence in both patient and animal models of PND suggested that neuroinflammation plays a critical role in the development and progression of this problem, therefore, mounting efforts have been made to develop novel therapeutic approaches for PND by targeting specific factors or steps alongside the neuroinflammation. Multiple studies have shown that perioperative anti-neuroinflammatory strategies via administering pharmacologic agents or performing nonpharmacologic approaches exert benefits in the prevention and management of PND, although more clinical evidence is urgently needed to testify or confirm these results. Furthermore, long-term effects and outcomes with respect to cognitive functions and side effects are needed to be observed. In this review, we discuss recent preclinical and clinical studies published within a decade as potential preventive and therapeutic approaches targeting neuroinflammation for PND.

Neuroprotective effects of sodium valproate on hippocampal cell and volume, and cognitive function in a rat model of focal cerebral ischemia

Valproate (VPA) as a histone deacetylase (HDAC) inhibitor has shown neuroprotective effects in neurodegenerative diseases. This study evaluated whether VPA treatment ameliorated the synaptic plasticity dysfunction, hippocampal neuronal loss, and spatial memory deficits induced by cerebral ischemia in the middle cerebral artery occlusion (MCAO) model. Thirty-two male Sprague-Dawley rats were randomly divided into 4 groups control, sham, cerebral ischemia+vehicle (MCAO+V), and MCAO+VPA. The right common carotid artery was occluded for 1 hour. VPA (300 mg/kg) or vehicles were injected intraperitoneally on days 0,1,2 and 3 of the reperfusion. After 7 days of reperfusion the Morris water maze, passive avoidance, and open field tests were performed. Hippocampal synaptic plasticity in the CA1 area was recorded by field potential recording. We used the term neuronal Input-Output (I/O) function and paired-pulse ratio (PPR) to refer to basal synaptic transmission and presynaptic neurotransmitter release probability respectively. After that, the brains were removed for assaying stereological parameters of the CA1 neurons. Our results showed the VPA administration significantly reduced the total infarct volume, improved MCAO-induced spatial learning -memory, fear memory, and anxiety compared to the MCAO+V group. In addition, the field potential recording showed that VPA significantly ameliorated the impaired the long- term potentiation (LTP) induced by MCAO, without any effects on basal synaptic transmission and neurotransmitter release probability. Therefore, it seems that a decrease in total infarct volume and induction of long-term potentiation via postsynaptic mechanisms is responsible for improving MCAO-induced cognitive impairment.

Hepatoprotective and neuroprotective effect of taxifolin on hepatic encephalopathy in rats

This study was planned to assess the potential protective effects of taxifolin against thioacetamide-induced hepatic encephalopathy and subsequently to portray its behavioural results. The experimental model was induced with three doses of (200 mg/kg i.p.) thioacetamide and taxifolin (50 and 100 mg/kg, p.o.) was administered for fourteen days. Taxifolin effectively attenuated hepatic encephalopathy through decrease in AST, ALT, ALP and LDH concentrations and improvement of hyperammonemia, and increase in antioxidant capacity by decreasing MDA, ROS, and increasing CAT and GSH. In addition, the expressions of NF-κB, TNF-α, IL-1β, caspase-3 and Bax was down-regulated while IL-10 and Bcl-2 expressions were up-regulated with taxifolin treatment. The recovery was confirmed by downregulation of iNOS and 8-OHdG expressions in our immunohistochemical analysis. Taxifolin treatment reduced the disrupting role of thioacetamide as seen by corrected hyperammonemia as well as preservation of astrocyte and hepatocyte structure. Elevated plus maze and locomotor activity tests also proved that taxifolin might repeal the neurobehavioral disabilities. In conclusion, taxifolin has shown hepatoprotective and neuroprotective roles with antioxidant and anti-inflammatory effects, as well as suppressing the excessive release of ammonia, and it eventually reversed neurobehavioral impairments.

The Minocycline Ameliorated the Synaptic Plasticity Impairment in Vascular Dementia

Chronic cerebral hypoperfusion (CCH) leads to vascular dementia with progressive hippocampal damage and cognitive impairments. In the present study, we compared early and late Minocycline (MINO) treatment on cognitive function, long and short-term synaptic-plasticity following CCH. We used bilateral common carotid arteries occlusion model (2VO) for induction of hypoperfusion. Male Sprague-Dawley rats were divided into 5 following groups (each having 2 subgroups): 2VO + V (vehicle), 2VO+MINO-E (early treatment of MINO on days 0 to 3 after 2VO), 2VO+MINO-L (late-treatment on days 21 to 32 after 2VO), control, and sham. Passive-avoidance (PA) and radial arm maze (RAM) tests were used to investigate learning and memory. Long term and short term synaptic plasticity were assessed by field potential recording, the brains were removed after recording and preserved for histological study to count pyramidal cells in CA1 region.Cerebral hypoperfusion could impair memory performance, synaptic plasticity, and basal synaptic transmission (BST) along with hippocampal cell loss. Thus, we found a significant reduction in step-through latency (STL) of PA test with a higher number of working and reference errors in RAM in CCH rats. However, only late treatment with MINO improved memory performance, synaptic plasticity, hippocampal cell loss, and increased neurotransmitter pool (NP) in CCH rats, but early treatment could not produce long-lasting beneficial effects 32 days after 2VO. MINO may improve synaptic plasticity and memory performance in hypo-perfused rats directly and indirectly by increasing NP and/or suppressing inflammatory factors, respectively.

Effects of platelet-rich plasma on the memory impairment, apoptosis, and hippocampal synaptic plasticity in a rat model of hepatic encephalopathy

OBJECTIVES

In the present study, we aimed to determine whether intraperitoneal injection of platelet-rich plasma (PRP) could have a neuroprotective effect on learning, memory, and synaptic plasticity impairment as well as hippocampal apoptosis in rats with hepatic encephalopathy induced by bile duct ligated (BDL).

METHODS

The rats were divided into four groups: the control, sham, BDL+ V (vehicle), and BDL+ PRP. The BDL rats were treated with PRP immediately after the surgery, and the injection was done every 3 days for 30 days. The passive avoidance and Morris water maze tests were used for the evaluation of learning and memory. The long-term potentiation (LTP), basal-synaptic transmission, and paired-pulse ratio, as an index for measurement of neurotransmitter release probability, were evaluated by field-potential recording. After taking a blood sample for assessment of the liver enzymes, the animals were sacrificed and their hippocampus was removed for evaluation of cleaved caspase-3 by Western blot.

RESULTS

Serological assessment of the liver function showed that BDL severely impaired the liver function. Also, PRP treatment could partially improve the liver dysfunction along with recovery in fear memory and spatial learning memory performance, LTP, basal-synaptic transmission, and neurotransmitter release probability. PRP-treated rats also showed a significant reduction in neuronal apoptosis in the CA1 area.

CONCLUSIONS

The results of this study suggest that PRP improves cognitive performance and synaptic plasticity in BDL rats via direct neuroprotective property and/or indirectly by improvement of hepatic dysfunction.

The neuroprotective properties and therapeutic potential of epidermal neural crest stem cells transplantation in a rat model of vascular dementia

INTRODUCTION

The incidence rate of senile dementia is rising, and there is no definite cure for it yet. Cell therapy, as a new investigational approach, has shown promising results. Hair bulges with abundant easily accessible neural stem cells permit autologous implantation in irreversible neurodegenerative disorders.

METHODS

Fifty rats were randomly divided into 5 groups of control, sham-operation, two-common carotid vessel-occlusion rats that received vehicle (2VO + V), 2VO rats that received 1 × 10⁶ epidermal stem cells (2VO + ESC1), and 2VO rats that received 2.5 × 10⁶ epidermal stem cells (2VO + ESC2) in 300 µl PBS intravenously on days 4, 9, and 14 after surgery. The epidermal neural crest stem cells (EPI-NCSCs) were isolated from hair follicles of rat whiskers. The open-field, passive avoidance, and Morris water maze were used as behavioral tests. The basal-synaptic transmission, long-term potentiation (LTP), and short-term synaptic plasticity were evaluated by field-potential recording of the CA1 hippocampal area.

RESULTS

30 days after the first transplantation in the 2VO + ESC1 group, functional recovery was prominent in anxiety and fear memory compared to the 2VO + ESC2 group, while LTP induction was recovered in both groups of grafted animals without improvement in basal synaptic transmission. These positive recoveries may be related to the release of different neurotrophic factors from grafted cells that can stimulate endogenous neurogenesis and synaptic plasticity.

CONCLUSIONS

Our results showed that EPI-NCSCs implantation could rescue LTP and cognitive disability in 2VO rats, while transplantation of 1 million cells showed better performance relative to 2.5 million cells.

Syringic acid protects against thioacetamide-induced hepatic encephalopathy: Behavioral, biochemical, and molecular evidence

The objective of this study was to elucidate the effects of syringic acid on thioacetamide-induced hepatic encephalopathy which is a complex serious syndrome with neuropsychiatric abnormalities related to acute liver dysfunctions like cirrhosis. Rats were treated with syringic acid (50 and 100 mg/kg, p.o.) for 14 days in treatment groups. Hepatic encephalopathy was induced by three doses of (200 mg/kg i.p.) thioacetamide injection. Syringic acid effectively alleviated thioacetamide-induced hepatic injury via reduction in ammonia, AST, ALT, ALP, LDH and decrease in oxidative stress (decreased MDA, ROS and increased SOD and GSH). Syringic acid also attenuated inflammatory injury by suppressing TNF-α, IL-1β, and NF-κB and increasing IL-10. The caspase-3 expression was also down-regulated in both liver and brain tissues. Immunohistochemical results confirmed the recovery with syringic acid by downregulation of iNOS, 8-OHdG and GFAP expression. Syringic acid decreased the deteriorating effects of thioacetamide as seen by reduced ammonia concentration and also preserved astrocyte and hepatocyte structure. The behavioral test results from elevated plus maze test, similar to the open-field locomotor test results, confirmed that syringic acid can reverse behavioral impairments. In conclusion, syringic acid exerted hepatoprotective and neuroprotective effects against hepatic encephalopathy by mitigating hepatotoxicity biomarkers, exerting antioxidant, anti-inflammatory effects in addition to suppressing hyperammonemia.

Choline chloride modulates learning, memory, and synaptic plasticity impairments in maternally separated adolescent male rats

Maternal separation (MS) is a model to induce permanent alternations in the central nervous system (CNS) and is associated with increased levels of anxiety and cognitive deficiencies. Since Methyl donor choline (Ch) has been shown to play a significant role in learning and memory and enhances synaptic plasticity, the authors hypothesized that Ch may attenuate MS-induced impairments in synaptic plasticity and cognitive performance. Rat pups underwent a MS protocol for 180 min/day from postnatal day (PND) 1 to 21. Ch was administered subcutaneously (100 mg/kg, 21 days) to the Choline chloride and MS + Choline chloride groups from PND 29 to 49. Anxiety-like behavior, recognition memory, spatial and passive avoidance learning and memory were measured in the adolescent rats. In addition, evoked field excitatory postsynaptic potentials (fEPSP) were recorded from the CA1 region of the hippocampus. MS induced higher anxiety-like behavior in the animals. It also impaired learning and memory. However, MS had no effect on locomotor activity. Subcutaneous administration of Ch attenuated MS-induced cognitive deficits and enhanced the learning and memory of MS rats. Ch also decreased anxiety-like behavior in the open field test. The present results showed that long-term potentiation (LTP) was induced in all groups except MS and MS + saline animals. However, Ch injection induced LTP and had maintenance in MS + choline chloride, but it was not statistically significant compared with the MS group. In summary, the present findings indicate that MS can interfere with normal animal's cognition and subcutaneous of Ch may be considered an appropriate therapeutic strategy for promoting cognitive dysfunctions in MS animals.

Enteral enriched nutrition to prevent cognitive dysfunction after surgery; a study in rats

Background

Inflammation plays an important role in postoperative cognitive dysfunction (POCD), particularly in elderly patients. Enteral enriched nutrition was shown to inhibit the response on inflammatory stimuli. Aim of the present study was to explore the therapeutic potential of enteral enriched nutrition in our rat model for POCD. The anticipated mechanism of action was examined in young rats, while responses in the target group of elderly patients were evaluated in old rats.

Methods

Male 3 and 23 months old Wistar rats received a bolus of enteral fat/protein-enriched nutrition 2 ​h and 30 ​min before surgery. The inflammatory response was evaluated by systemic inflammation markers and brain microglia activity. Additionally, in old rats, the role of the gut-brain axis was studied by microbiome analyses of faecal samples. Days 9–14 after surgery, rats were subjected to cognitive testing. Day 16, rats were sacrificed and brains were collected for immunohistochemistry.

Results

In young rats, enriched nutrition improved long-term spatial learning and memory in the Morris Water Maze, reduced plasma IL1-β and VEGF levels, but left microglia activity and neurogenesis unaffected. In contrast, in old rats, enriched nutrition improved short-term memory in the novel object- and novel location recognition tests, but impaired development of long-term memory in the Morris Water Maze. Systemic inflammation was not affected, but microglia activity seemed even increased. Gut integrity and microbiome were not affected.

Conclusion

Enteral enriched nutrition before surgery in young rats indeed reduced systemic inflammation and improved cognitive performance after surgery, whereas old rats showed a mixed favorable/unfavorable cognitive response, without effect on systemic inflammation. Anti-inflammatory effects of enriched nutrition were not reflected in decreased microglia activity. Neither was an important role for the gut-brain axis observed. Since the relatively straight forward effects of enriched nutrition in young rats could not be shown in old rats, as indicated by a mixed beneficial/detrimental cognitive outcome in the latter, caution is advised by translating effects seen in younger patients to older ones.

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Enriched nutrition reduced inflammation after surgery in young rats.

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Enriched nutrition improved postoperative cognitive outcome in young rats.

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Enteral enriched nutrition did not inhibit neuroinflammation.

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Effects in young rats do not predict effects in old rats.

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Enteral enriched nutrition caused mixed improved/declined cognition in old rats.

Acute pre-operative ibuprofen improves cognition in a rat model for postoperative cognitive dysfunction

BACKGROUND

Inflammation is considered a key factor in the development of postoperative cognitive dysfunction (POCD). Therefore, we hypothesized that pre-operative anti-inflammatory treatment with ibuprofen would inhibit POCD in our rat-model.

METHODS

Male Wistar rats of 3 or 23 months old received a single injection of ibuprofen (15 mg/kg i.p.) or were control handled before abdominal surgery. Timed blood and fecal samples were collected for analyses of inflammation markers and gut microbiome changes. Behavioral testing was performed from 9 to 14 days after surgery, in the open field, novel object- and novel location-recognition tests and Morris water maze. Neuroinflammation and neurogenesis were assessed by immune histochemistry after sacrifice on postoperative day 14.

RESULTS

Ibuprofen improved short-term spatial memory in the novel location recognition test, and increased hippocampal neurogenesis. However, these effects were associated with increased hippocampal microglia activity. Whereas plasma cytokine levels (IL1-β, IL6, IL10, and TNFα) were not significantly affected, VEGF levels increased and IFABP levels decreased after ibuprofen. Long-term memory in the Morris water maze was not significantly improved by ibuprofen. The gut microbiome was neither significantly affected by surgery nor by ibuprofen treatment. In general, effects in aged rats appeared similar to those in young rats, though less pronounced.

CONCLUSION

A single injection of ibuprofen before surgery improved hippocampus-associated short-term memory after surgery and increased neurogenesis. However, this favorable outcome seemed not attributable to inhibition of (neuro)inflammation. Potential contributions of intestinal and blood-brain barrier integrity need further investigation. Although less pronounced compared to young rats, effects in aged rats indicate that even elderly individuals could benefit from ibuprofen treatment.

Hepatic Encephalopathy: From Metabolic to Neurodegenerative

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome of both acute and chronic liver disease. As a metabolic disorder, HE is considered to be reversible and therefore is expected to resolve following the replacement of the diseased liver with a healthy liver. However, persisting neurological complications are observed in up to 47% of transplanted patients. Several retrospective studies have shown that patients with a history of HE, particularly overt-HE, had persistent neurological complications even after liver transplantation (LT). These enduring neurological conditions significantly affect patient's quality of life and continue to add to the economic burden of chronic liver disease on health care systems. This review discusses the journey of the brain through the progression of liver disease, entering the invasive surgical procedure of LT and the conditions associated with the post-transplant period. In particular, it will discuss the vulnerability of the HE brain to peri-operative factors and post-LT conditions which may explain non-resolved neurological impairment following LT. In addition, the review will provide evidence; (i) supporting overt-HE impacts on neurological complications post-LT; (ii) that overt-HE leads to permanent neuronal injury and (iii) the pathophysiological role of ammonia toxicity on astrocyte and neuronal injury/damage. Together, these findings will provide new insights on the underlying mechanisms leading to neurological complications post-LT.

Treatment with edaravone improves the structure and functional changes in the hippocampus after chronic cerebral hypoperfusion in rat

This study aimed to find out cellular and electrophysiological effects of the edaravone (EDR) administration following induction of vascular dementia (VaD) via bilateral-carotid vessel occlusion (2VO). The rats were randomly divided into control, sham, 2VO + V (vehicle), and 2VO + EDR groups. EDR was administered once a day from day 0-28 after surgery. The passive-avoidance, Morris water-maze, and open-field tests were used for evaluation of memory, locomotor, and anxiety. The field-potential recording was used for assessment of electrophysiological properties of the hippocampus; and after sacrificing, the cerebral hemispheres were removed for stereological study and evaluation of MDA levels. The long-term potentiation (LTP), paired-pulse ratio (PPR), and input-output (I/O) curves were evaluated as indexes for long-term and short-term synaptic plasticity, and basal-synaptic transmission (BST), respectively. The 2VO led to increases in MDA level with considerable neuronal loss and decreases in the volume of the hippocampus, along with a reduction in the BST and LTP induction which was associated with a decrement in PPR and ultimate loss in memory with higher anxiety behavior. However, administration of EDR caused a decline in MDA and prevented the neural loss and volume of the hippocampus, rescued BST and LTP depression, improved memory and anxiety without any effects on PPR. Therefore, most likely through the improvement of MDA level, and the hippocampal cell number and volume, EDR leads to recovery of synaptic plasticity and behavioral performance. Because of the LTP rescue, without recovery of PPR, it is likely that the EDR improved LTP through the post-synaptic neurons.

The effects of thymoquinone on memory impairment and inflammation in rats with hepatic encephalopathy induced by thioacetamide

Hepatic encephalopathy (HE) is a prevalent complication of the central nervous system (CNS) that is caused by acute or chronic liver failure. This study was designed to evaluate the effects of thymoquinone (TQ) on thioacetamide (TAA)-induced HE in rats, and determine the consequential behavioral, biochemical, and histological changes. HE was induced in male Wistar rats by intraperitoneal (i.p.) injection of 200 mg/kg TAA once every 48 h for 14 consecutive days. Control groups received the normal saline containing 5 % DMSO. Thymoquinone (5, 10, and 20 mg/kg) was administered for ten consecutive days intraperitoneally (i.p.) after HE induction and it was continued until the end of the tests. Then, the passive avoidance memory, extracellular single unit, BBB permeability, and brain water content were evaluated. Moreover, hippocampal tissues were used for evaluation of oxidative stress index, inflammatory biomarkers, and histological parameters following HE. As result of the treatment, TQ improved passive avoidance memory, increased the average number of simultaneous firing of spikes/bins, improved the integrity of BBB, and decreased brain water content in the animal model of HE. Furthermore, the results indicated that treatment with TQ decreased the levels of inflammatory cytokines (TNF-α and IL-1β) but increased the levels of glutathione (GSH) and anti-inflammatory cytokine (IL-10) of the surviving cells in the hippocampal tissues. This study demonstrates that TQ may have beneficial therapeutic effects on cognitive, oxidative stress, neuroinflammatory, and histological complications of HE in rat.