Crosstalk mechanisms in hepatoprotection: Thyroid hormone-docosahexaenoic acid (DHA) and DHA-extra virgin olive oil combined protocols.

Normal liver function includes a number of metabolic processes, secretion of cellular mediators and its role in immunobiology; these require a high energy supply, which is further enhanced under adverse conditions triggering hepatic disorders or injury due to the operation of counteracting mechanisms. Alterations in oxygen availability, such as ischemia-reperfusion (IR) leading to liver inflammation and high-fat diet (HFD)-induced hepatic steatosis, are noxious responses encountered in hepatic surgery and obesity, respectively. Several strategies have been developed to attenuate or prevent these disorders, including thyroid hormone (T3), docosahexaenoic acid (DHA) and extra virgin olive oil (EVOO). These hormetic agents that exert beneficial effects in the low dose range were shown to abrogate IR-induced liver injury effectively in the case of T3, DHA, or their combined administration, whereas DHA plus EVOO attenuate HFD-induced hepatic steatosis, although they can induce adverse effects in other experimental settings. The use of combined hepatoprotective protocols (DHA + T3 or DHA + EVOO) using low doses or reduced supplementation periods is characterized by the stimulation of different types of molecular defensive mechanisms and similar signaling processes that exhibit synergism, thus constituting suitable experimental liver pharmacological preconditioning strategies with possible future clinical applications.