An Anatomist's View on the Crosstalk Between the Liver and the Lung

ABSTRACT A possible interaction between liver and lung in health and disease has attracted growing interest. From an anatomist's perspective, the liver and the lung share many morphological, physiological, and developmental analogies. Both organs supply the body with important substances from the environment (nutrients, oxygen). Even though the liver receives nutrients from the intestine via the portal vein and is therefore not in direct contact with the external environment, the three‐dimensional organ architecture is similar, as both organs need an inflow from external substances as well as a dual blood supply (vasa privata and vasa publica). The cellular architecture is linked to the anatomical location and function, and cells of both organs share comparable anatomical and functional characteristics. In addition, there are (patho‐)physiologic mechanisms including liver and lung such as the renin‐angiotensin system, lipid metabolism, regeneration, as well as bacterial translocation and acute phase response. Dysfunction of one organ can therefore influence the other organ as well. As a consequence, there are many different diseases affecting both organs, such as hepatopulmonary syndrome, obstructive sleep apnea, acute respiratory distress syndrome, portopulmonary hypertension, and others. Liver and lung are either both affected by a systemic stimulus, or one of the organs is causally diseased and secondarily affects the other. Nevertheless, detailed knowledge about pathomechanisms is mostly lacking. By analyzing and comparing the structural and functional characteristics of liver and lung, the present review article aims at providing the reader with a comprehensive overview about the anatomical basis of the liver‐lung axis.