Kidney–lung pathophysiological crosstalk: its characteristics and importance

Crosstalk between the lung and the kidney is based on the similarities that these organs share. This is why different diseases that affect one organ can have repercussions on the other. Patients with acute kidney injury can present complications such as pulmonary edema and require mechanical ventilation in respiratory failure. This interaction occurs due to the increase in systemic immune mediators that cause inflammatory reactions, oxidative stress, and an increase in vascular permeability in the lung. With regard to lung-induced renal damage, the kidney can also be affected by chemical mediators, which are translocated into the bloodstream. Moreover, the kidneys are extremely sensitive to oxygen changes which can cause them to lose their autoregulation mechanism. In patients with acute lung injury (ALI), oxygen supply is decreased causing renal hypoxia. Besides, hypercapnia generated by ALI causes vasoconstriction in the renal vascular network and activation of the renal angiotensin aldosterone system. ALI not only can cause renal injury, but also worsening chronic obstructive pulmonary disease and obstructive sleep apnea. In conclusion, kidney–lung crosstalk is commonly present in certain pathological states, and knowing its characteristics is crucial for managing the complications which may arise from this vicious circle.