Urine citrate excretion as a marker of acid retention in patients with chronic kidney disease without overt metabolic acidosis

The membrane protein ANKH is crucial for bone mechanical performance by mediating cellular export of citrate and ATP

“…Possibly, the human patient with biallelic inactivating mutations in ANKH had a diet that was low in citrate, whereas part of the citrate detected in plasma of Ank ank/ank mice comes from dietary sources. Other factors potentially contributing to differences in urinary citrate excretion between humans and mice lacking functional ANKH/Ank are the differences in transport kinetics of the human and mouse citrate uptake transporters[ 25 ] and plasma acid-base status[ 26 ]. SLC13A5 is an uptake transporter crucially involved in citrate excretion, by reabsorbing citrate from primary urine.…”

Spot urinary citrate-to-creatinine ratio is a marker for acid-base status in chronic kidney disease

“…Thus, to assess acid loading on an organism, it is much more logical to measure the defense mechanism (urinary citrate excretion) rather than the defended parameter (serum [HCO 3 -]). Urine citrate excretion has been suggested to identify changes in acid retention with progressive decline in renal function 46,47 , and post-base loading in CKD 48 .…”

Metabolic Acidosis and CKD Progression

“…Drawing on this evidence, the association between H 1 retention and urine citrate excretion in eubicarbonatemic patients with CKD 1 and 2 was evaluated before and after a 30-day administration of HCO 3 2 -producing fruits and vegetables. A mixed effects regression model showed that urine citrate excretion was strongly predictive of H 1 retention and reliably verified reduction in H 1 retention after fruits and vegetables (10). Furthermore, changes in urine citrate excretion identified changes in H 1 retention as eGFR declines in eubicarbonatemic patients with CKD 2 (8).…”