Amira Atta, Maha M Salem, Tarek M Mohamed
Hepatic encephalopathy (HE) represents an essential neuropsychological disorder resulting from liver dysfunction that is mainly caused by disorders of ammonia elimination, hyperammonemia, oxidative stress, and inflammation in the brain. Even with modern methods of treatment directed at lowering ammonia levels in plasma, HE continues to be characterized by incomplete metabolic alterations. Due to new data regarding metabolic processes, the significance of the proline cycle and its participation in nitrogen transportation have been discovered recently. Δ¹-Pyrroline-5-carboxylate dehydrogenase (Δ¹P5CDH) converts P5C into glutamate in this pathway, thus establishing the connection between proline metabolism and nitrogen metabolism. The purpose of this review is to investigate the possible relation between the proline cycle, nitrogen metabolism via Δ¹P5CDH, and HE. The possible role of the modulation of nitrogen metabolism via the ornithine-P5C-glutamate cycle in the context of HE is especially considered. Moreover, the significance of liposomal L-ornithine in this process is studied as a method of drug delivery. This paper discusses a mechanistically and hypothesis-driven approach to the recent interactions among proline metabolism, ammonia regulation, oxidative stress, and liposomal L-ornithine. While existing literature may show some relevance to the use of these interactions for therapeutic purposes, more biochemical, experimental, and clinical investigations are necessary to ascertain their validity and translational importance in hepatic encephalopathy.