Influence of iron manipulation on hypoxic pulmonary vasoconstriction and pulmonary reactivity during ascent and acclimatization to 5050 m

Key points Iron acts as a cofactor in the stabilization of hypoxic-inducible factor family, and plays an influential role modulation hypoxic pulmonary vasoconstriction. It is uncertain whether iron regulation altered lowlanders during either (1) ascent to high altitude, or (2) following partial acclimatization, when compared high-altitude adapted Sherpa. During 5050 m, rise artery systolic pressure (PASP) was blunted Sherpa, lowlanders; however, upon arrival PASP levels were comparable both groups, but reduction bioavailability more prevalent Following acclimatization there differential influences status manipulation (via infusion chelation) at rest exercise between Sherpa on vasculature. Abstract To examine adaptational vascular responses acute chronic hypobaric hypoxia, haematological cardiopulmonary profile determined during: 9-day m (20 12 Sherpa), (11 ± 4 days) (18 20 where groups received i.v. (iron (iii)-hydroxide sucrose) chelator (desferrioxamine). ascent, reductions Sherpa; appeared demonstrate efficient capacity mobilize stored iron, lowlanders, expressed ?hepcidin per unit change body soluble transferrin receptor index, 3400–5050 (P = 0.016 P 0.029, respectively). The ascent; m. despite demonstrating ventilatory response greater resting hypoxaemia, they had similar vasoconstriction rest. Iron-infusion attenuated 0.005), while chelation did not exaggerate group exaggerated hypoxaemia ( 67 mmHg). 25% peak wattage, only consistently elevated which persisted chelation. These findings provide new evidence complex interplay adaptation altitude.