Table 1.
Microscopic findings of the renal biopsies.
Fig 1.
Comparison of serum klotho levels in different groups for each pathology.
Boxplots for serum klotho levels are presented according to the severity of each pathologic finding: (A) Interstitial fibrosis, (B) tubular atrophy, (C) segmental sclerosis of glomeruli, and (D) intimal thickening of arterial wall. *P < 0.01; **P < 0.001.
Fig 2.
Representative images of Masson’s trichrome-stained kidney sections according to serum klotho levels.
(A) The specimen from 68-year-old male patient with IgA nephropathy and serum klotho level of 790.9 pg/mL showed nearly intact interstitium and glomerulus. (B) The specimen from a 38-year-old male patient with IgA nephropathy and serum klotho level of 6.4 pg/mL showed marked interstitial fibrosis and tubular atrophy (white arrow), and sclerosing glomerulus (black arrow). Scale bar = 200 μm.
Table 2.
Baseline demographics and clinical characteristics according to serum klotho level.
Table 3.
Association of serum klotho level with interstitial fibrosis and segmental sclerosis.
Fig 3.
Association of log-transformed urinary klotho-to-creatinine ratio with global sclerosis and foot process effacement.
Boxplots for log-transformed urinary klotho-to-creatinine ratio are shown according to the severity of each pathological finding: (A) Global glomerular sclerosis, (B) foot process effacement of podocyte. *P < 0.05; **P < 0.01. UKCR: urinary klotho-to-creatinine ratio.
Table 4.
Baseline demographics and clinical characteristics based on urinary klotho-to-creatinine ratio.
Fig 4.
Representative transmission electron microscopy images according to urinary klotho-to-creatinine ratio.
(A) The specimen obtained from a 55-year-old male patient with IgA neprhopathy and a urinary klotho-to-creatinine ratio of 30.83 pg/mgCr showed preserved foot process of podocyte. (B) The specimen obtained from a 58-year-old male patient with IgA nephropathy and a urinary klotho-to-creatinine ratio of 0.44 pg/mgCr showed diffuse effacement of foot process (arrows). Scale bar = 5 μm.
Table 5.
Association of each pg/mgCr increase in log urinary klotho-to-creatinine ratio and diffuse foot process effacement.
Fig 5.
Receiver-operating characteristic (ROC) analyses for predicting renal pathology.
ROC curves are shown according to the predictors and outcomes: (A) ROC curve for predicting interstitial fibrosis based on serum klotho, (B) ROC curve for predicting segmental sclerosis based on serum klotho, and (C) ROC curve for predicting foot process effacement based on the urinary klotho-to-creatinine ratio. Best cut-off values were presented as black circles and certain values (with specificity and sensitivity). AUC, area under the ROC curve; UKCR, urinary klotho-to-creatinine ratio.
Fig 6.
Comparison of the klotho immunohistochemistry (IHC) staining score based on each pathologic finding.
Boxplots for klotho IHC staining score are shown according to the severity of each pathologic finding: (A) Interstitial fibrosis and (B) tubular atrophy. IHC staining score for distal tubule were calculated as: percentage of strongly stained distal tubule × 2 + percentage of weakly stained distal tubule.
Fig 7.
Representative images of immunohistochemistry (IHC) staining for klotho based on adjacent pathological features.
(A) Distal tubules surrounded by normal tubuloinsterstitium showed strong IHC staining for klotho (white arrows). (B) Distal tubules surrounded by inflamed interstitium and atrophic tubules showed absent or weak IHC staining for klotho (black arrows). Scale bar = 100 μm.