. 2019 Feb 19;9(3):362–382. doi: 10.1016/j.jceh.2019.02.003

Table 1.

Summary of the Main Results Published to Date Using Different Ex Vivo Techniques in Chronic HE Animal Models.

Animal model	Subjects (n)	Method	Brain region	Type of measurement	Findings			Comments	Ref
Animal model	Subjects (n)	Method	Brain region	Type of measurement	Edema	Type of edema Cell type	Other	Comments	Ref
BDL rats Sham rats	8 9 8-10	Gravimetry, 3 weeks post-BDL GFAP staining HPLC – osmolytes Behavior studies	CC, 2mm² FC, PC	Ex-vivo, end point Ex-vivo, end point Ex-vivo, end point	Direct, absolute assessment of water content Indirect indication	N/A Direct evidence, astrocytes	No change in water content = 79.73±0.12% No changes in GFAP staining in BDL rats Minor and non-significant changes in brain Gln and Ins	No change in plasma and brain ammonia (122±70 μmol/L in plasma and 0.29±0.18μmol/g in brain of BDL) Mild impairment of motor coordination and a ↓spontaneous motor activity in BDL rats LPS: ↑brain water content and Alzheimer type II astrocytes	133
BDL rats Sham rats	7 6	Gravimetry, 4 weeks post-BDL Ex-vivo¹H MRS, no information on quantification Electron microscopy Assessment of level of consciousness	FC, CC – 2mm²	Ex-vivo, end point Ex-vivo, end point Ex-vivo, end point	Direct, absolute assessment of water content	N/A Direct evidence- cytotoxic edema, astrocytes	No change in water content = 79.9±0.27% ↓ Gln, NAA Partially collapsed microvessel Intact BBB	↑ plasma (168±14μmol/L) and brain (1.0±0.36μmol/g) ammonia No neurological modifications in BDL rats Among the very few reports showing a*↓Gln* Minimal water accumulation in astrocytic, perivascular tissue LPS injection ↑brain water content and lead to a deterioration of tin the conscious level	26
BDL rats Sham rats	6 6	Gravimetry, 6 weeks post-BDL Locomotor activity	FC, 2mm³	Ex-vivo, end point	Direct, absolute assessment of water content	N/A	↑water content = 79.46±0.28% (BDL) vs 78.35±0.17% (sham) Allopurinol treatment decreased arterial ROS and brain edema but did not improve liver function nor fully restored locomotor activity-edema is not the only cause of HE	↑ arterial (119.7±15.2μM) and CSF (128.4±36.7μM) ammonia HA does not induce OS independently nor brain edema In combination systemic OS and HA stimulate an ↑water content Systemic OS is a result of primary liver injury	24
BDL rats Sham rats	7 6	Gravimetry, 6 weeks post-BDL	FC, 1mm³	Ex-vivo, end point	Direct, absolute assessment of water content	N/A	-no significant change in water content between BDL and sham rats	Exact water content difficult to assess from the graph = 81.5-82.5% (BDL) LPS injection ↑brain water content	25
BDL rats Sham rats	No indication on number of rats was found	Gravimetry, 6 weeks post-BDL Ex vivo¹H MRS, no information on quantification Ex vivo fluorescence	FC	Ex-vivo, end point Ex-vivo, end point	Direct, absolute assessment of water content	N/A	↑water content ↑Gln, Glu, Tau ↓Ins ↑sum of osmolytes ↑brain Lac, ↑CSF ammonia AST-120 and DCA treatments ↓ brain edema, Lac but not brain Gln Only AST-120 ↓ CSF ammonia	Exact water content was difficult to assess from the graph = 78-79% (BDL) Correlations: No correlation between CSF ammonia and brain Gln Correlation between CSF ammonia and brain Lac ↑brain Lac and not Gln is a key factor in pathogenesis of brain edema together with impaired compensatory osmoregulatory mechanisms	95
BDL rats Sham rats	6 groups (6/group) 3 groups (6/group)	Dry weight technique, 4 weeks post-BDL Assessment of level of consciousness	50 mm² wet FC	Ex-vivo, end point	Direct, absolute assessment of water content	N/A	No change in water content in BDL rats ↑water content in shams +HD and shams+LPS ↑water content in BDL+HD and BDL+HD+LPS ↓ water content after administration of OP and OP + infliximab	↑arterial and brain ammonia in HD and BDL rats; and ↓ after OP (±infliximab) ↓arterial ammonia with OP may prevent LPS induced worsening of HE and brain edema. Exact values of water content and ammonia were difficult to assess from the graphs	134
BDL rats Sham rats	9 groups (6-8/group) 2 groups (7/group)	Dry weight technique, 4 weeks post-BDL Ex vivo¹H MRS, no information on quantification	50 mm² wet FC (GM)	Ex-vivo, end point	Direct, absolute assessment of water content	N/A	↑plasma ammonia in BDL rats (67±6 to 186±20 μmol/L) ↑water content in BDL rats No change in brain Gln in BDL rats ↓ brain mIns in BDL rats OP treatment: ↓brain water content and plasma ammonia, no change in brain Gln or mIns,	Exact values of water content were difficult to assess from the graphs (∼76% in Shams and ∼78% in BDL)	135

Abbreviations: Frontal cortex (FC), Cerebral cortex (CC), parietal cortex (PC), gray matter (GM), oxidative stress (OS), reactive oxygen species (ROS), blood brain barrier (BBB), hepatic encephalopathy (HE), cerebrospinal fluid (CSF), lactate (Lac), glutamine (Gln), taurine (Tau), inositol (Ins), myo-inositol (mIns), glutamate (Glu), lipopolysaccharide (LPS), hyperammonemia (HA), glial fibrillary acidic protein (GFAP), bile duct ligation (BDL), ornithine phenylacetate (OP), oral ammonia absorbent engineered activated carbon microspheres (AST-120), dichloroacetate (DCA), proton magnetic resonance spectroscopy (¹H MRS), high protein/ammoniagenic diet (HD). Authors personal comments are in italics in the comments row.