Altitude and arteriolar hyalinosis after kidney transplantation

The kidney is very susceptible to hypoxic injury. Calcineurin inhibitors (CNIs) induce vasoconstriction and might reduce renal tissue oxygenation. We aimed to investigate if the synergistic deleterious effects of CNI-treatment and hypoxia of high altitude living might accelerate the development of arteriolar hyalinosis in kidney allografts. We stratified all patients who received a kidney graft from 2000 to 2010 in our centre (n = 477) in three groups according to the residential elevation (below 400, between 400 to 600 and above 600 m above sea level) and we retrospectively re-evaluated all transplant biopsies performed during follow-up, specifically looking at the degree of arteriolar hyalinosis, the hallmark of chronic CNI nephrotoxicity. Living at high altitude was markedly associated with a higher degree of arteriolar hyalinosis (P < 0.001). Haemoglobin levels confirmed the functional relevance of different arterial oxygenation among the groups (P = 0.01). Thus, patients living at high altitude seem to be more susceptible to the development of arteriolar hyalinosis after kidney transplantation.