Caracterización de la neuroinflamación en modelos animales y en pacientes con encefalopatía hepática. Implicaciones terapéuticas
Varios millones de personas afectadas por enfermedades hepáticas crónicas (cirrosis, hepatitis) muestran alteraciones neurológicas, denominadas encefalopatía hepática (HE) con alteraciones cognitivas y motoras que deterioran la calidad de vida y reducen la esperanza de vida. La carga económica de la encefalopatía hepática es sustancial, con un costo estimado entre mil y siete mil millones de dólares por año en los EE.UU. La patogénesis de la encefalopatía hepática y los mecanismos que conducen a las alteraciones neurológicas aún no se entienden completamente. Algunos estudios sugieren la presencia de neuroinflamación en pacientes con cirrosis hepática o hepatitis C. Estudios en modelos anim…
Differential role of interleukin-1β in neuroinflammation-induced impairment of spatial and nonspatial memory in hyperammonemic rats.
Activated microglia and increased brain IL-1β play a main role in cognitive impairment in much pathology. We studied the role of IL-1β in neuroinflammation-induced impairment of the following different types of learning and memory: novel object recognition (NOR), novel object location (NOL), spatial learning, reference memory (RM), and working memory (WM). All these processes are impaired in hyperammonemic rats. We assessed which of these types of learning and memory are restored by blocking the IL-1 receptor in vivo in hyperammonemic rats and the possible mechanisms involved. Blocking the IL-1 receptor reversed microglial activation in the hippocampus, perirhinal cortex, and prefrontal cor…
Histological Features of Cerebellar Neuropathology in Patients With Alcoholic and Nonalcoholic Steatohepatitis
Alcoholic steatohepatitis (ASH) and nonalcoholic steatohepatitis (NASH) affect 29 million people in the European Union. Patients with ASH and NASH may exhibit cognitive impairment, reducing their quality of life. Steatohepatitis induces cerebral alterations. It is not known if histological analysis could allow distinguishing ASH, NASH, and/or cirrhosis neuropathology and other entities. The aim of this work was to analyze a set of histopathological features characterizing the brain lesions due to ASH, NASH, and cirrhosis. We performed a histological study using hematoxylin and eosin staining and immunohistochemical techniques in cerebellum of 31 subjects who died with healthy liver (n = 6),…
Interplay between glutamatergic and GABAergic neurotransmission alterations in cognitive and motor impairment in minimal hepatic encephalopathy.
The cognitive and motor alterations in hepatic encephalopathy (HE) are the final result of altered neurotransmission and communication between neurons in neuronal networks and circuits. Different neurotransmitter systems cooperate to modulate cognitive and motor function, with a main role for glutamatergic and GABAergic neurotransmission in different brain areas and neuronal circuits. There is an interplay between glutamatergic and GABAergic neurotransmission alterations in cognitive and motor impairment in HE. This interplay may occur: (a) in different brain areas involved in specific neuronal circuits; (b) in the same brain area through cross-modulation of glutamatergic and GABAergic neur…
Reducing Peripheral Inflammation with Infliximab Reduces Neuroinflammation and Improves Cognition in Rats with Hepatic Encephalopathy
Inflammation contributes to cognitive impairment in patients with hepatic encephalopathy (HE). However, the process by which peripheral inflammation results in cognitive impairment remains unclear. In animal models, neuroinflammation and altered neurotransmission mediate cognitive impairment. Taking into account these data, we hypothesized that in rats with HE: (1) peripheral inflammation is a main contributor to neuroinflammation; (2) neuroinflammation in hippocampus impairs spatial learning by altering AMPA and/or NMDA receptors membrane expression; (3) reducing peripheral inflammation with infliximab (anti-TNF-a) would improve spatial learning; (4) this would be associated with reduced n…
The Dual Role of the GABAA Receptor in Peripheral Inflammation and Neuroinflammation: A Study in Hyperammonemic Rats
Cognitive and motor impairment in minimal hepatic encephalopathy (MHE) are mediated by neuroinflammation, which is induced by hyperammonemia and peripheral inflammation. GABAergic neurotransmission in the cerebellum is altered in rats with chronic hyperammonemia. The mechanisms by which hyperammonemia induces neuroinflammation remain unknown. We hypothesized that GABAA receptors can modulate cerebellar neuroinflammation. The GABAA antagonist bicuculline was administrated daily (i.p.) for four weeks in control and hyperammonemic rats. Its effects on peripheral inflammation and on neuroinflammation as well as glutamate and GABA neurotransmission in the cerebellum were assessed. In hyperammone…