Urine inositol pentakisphosphate 2-kinase and changes in kidney structure in early diabetic kidney disease in type 1 diabetes

Am J Physiol Renal Physiol. 2018 Nov 1;315(5):F1484-F1492. doi: 10.1152/ajprenal.00183.2018. Epub 2018 Aug 22.


We examined the association of urine inositol 1,3,4,5,6-pentakisphosphate 2-kinase (IPP2K) with the presence and progression of diabetic kidney disease (DKD) lesions. Urine IPP2K was measured at baseline by quantitative liquid chromatography-mass spectrometry in 215 participants from the Renin-Angiotensin System Study who had type 1 diabetes and were normoalbuminuric and normotensive with normal or increased glomerular filtration rate (GFR). Urine IPP2K was detectable in 166 participants. Participants with IPP2K below the limit of quantification (LOQ) were assigned concentrations of LOQ/√2. All concentrations were then standardized to urine creatinine (Cr) concentration. Kidney morphometric data were available from biopsies at baseline and after 5 yr. Relationships of IPP2K/Cr with morphometric variables were assessed by linear regression after adjustment for age, sex, diabetes duration, hemoglobin A1c, mean arterial pressure, treatment assignment, and, for longitudinal analyses, baseline structure. Baseline mean age was 29.7 yr, mean diabetes duration 11.2 yr, median albumin excretion rate 5.0 μg/min, and mean iohexol GFR 129 ml·min-1·1.73m-2. Higher IPP2K/Cr was associated with higher baseline peripheral glomerular total filtration surface density [Sv(PGBM/glom), tertile 3 vs. tertile 1 β = 0.527, P = 0.011] and with greater preservation of Sv(PGBM/glom) after 5 yr ( tertile 3 vs. tertile 1 β = 0.317, P = 0.013). Smaller increases in mesangial fractional volume ( tertile 3 vs. tertile 1 β = -0.578, P = 0.018) were observed after 5 yr in men with higher urine IPP2K/Cr concentrations. Higher urine IPP2K/Cr is associated with less severe kidney lesions at baseline and with preservation of kidney structure over 5 yr in individuals with type 1 diabetes and no clinical evidence of DKD at baseline.

Keywords: biomarker; diabetic kidney disease; inositol pentakisphosphate 2-kinase; kidney morphometry.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Adult
  • Biomarkers / urine
  • Biopsy
  • Chromatography, High Pressure Liquid
  • Chromatography, Reverse-Phase
  • Clinical Trials as Topic
  • Diabetes Mellitus, Type 1 / complications*
  • Diabetes Mellitus, Type 1 / diagnosis
  • Diabetic Nephropathies / enzymology
  • Diabetic Nephropathies / etiology
  • Diabetic Nephropathies / pathology*
  • Diabetic Nephropathies / urine*
  • Disease Progression
  • Female
  • Humans
  • Kidney / pathology*
  • Male
  • Mass Spectrometry
  • Multicenter Studies as Topic
  • Phosphotransferases (Alcohol Group Acceptor) / urine*
  • Time Factors
  • Up-Regulation
  • Young Adult


  • Biomarkers
  • Phosphotransferases (Alcohol Group Acceptor)
  • inositol 1,3,4,5,6-pentakisphosphate 2-kinase