19/06/2025
The pathophysiology of iron deficiency in chronic inflammation. Increased cytokine levels in all conditions, and decreased renal clearance in CKD and CHF, result in enhanced hepcidin levels. These inflammatory effects are are seen in hospitalised patients. High hepcidin levels bind, internalize and degrade ferroportin on the lateral membrane of duodenal enterocytes and spleen macrophages. Iron remains trapped in enterocytes, which are then shed in the gut. Iron is also sequestered into macrophages, which are responsible for destroying senescent red blood cells and recycling their iron. Serum ferritin levels are regulated by the iron content of macrophages and increase in inflammation (apoferritin as an acute-phase protein). A decrease in circulating iron leads to lower amounts of iron bound to the iron carrier protein, transferrin, and subsequently to a decline in transferrin saturation and low iron supply to all organs. Furthermore, cytokines may also have negative effects on erythropoietin production in the kidney and erythroid cell maturation, while also increasing macrophage iron retention. Note that the increased iron losses that can occur in specific chronic inflammatory conditions are not illustrated here. Plus and minus signs represent increase/enhancement and decrease, respectively. EPO, erythropoietin; FPN, ferroportin; IL, interleukin; TNF, tumor necrosis factor; TSAT, transferrin saturation1070 | A JHA JH CAPPELLINI ET AL .