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Elevated Klotho promoter methylation is associated with severity of chronic kidney disease.

Chen J, Zhang X, Zhang H, Lin J, Zhang C, Wu Q, Ding X - PLoS ONE (2013)

Bottom Line: Higher levels of KL promoter methylation were observed in renal tissue and PBMC in patients with CKD compared with controls (8.79±3.24 vs. 5.17±1.11%, P<0.001; 7.20±2.79 vs. 3.27±0.79%, P<0.001).Estimated glomerular filtration rate correlated inversely with renal and PBMC levels of KL promoter methylation (r=-0.829, P<0.001; r=-0.645, P<0.001), while tubulointerstistial fibrosis score correlated positively (ρ=0.826, P<0.001; ρ=0.755, P<0.001).The degree of KL promoter methylation is associated with clinical and histological severity of CKD.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Kidney Disease, Zhongshan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.

ABSTRACT
Klotho (KL) expression is down-regulated in the renal tissues of chronic kidney disease (CKD) animal models and patients with end-stage renal disease. The putative role of KL promoter hypermethylation in the progression of CKD remains unclear. The present study aimed to determine renal and peripheral blood mononuclear cells (PBMC) levels of KL promoter methylation and analyze their relationship with clinical and histological severity in patients with CKD. Using bisulfite pyrosequencing, renal and PBMC levels of KL promoter methylation were quantified in 47 patients with CKD. 47 nephrectomy specimens of patients with renal cell carcinoma and 48 PBMC specimens of healthy volunteers were used as renal tissue and PBMC controls, respectively. Renal expression of KL protein was assayed by immunohistochemistry staining. Receiver operating characteristic (ROC) curve was used to identify the optimal cut-off value of PBMC KL promoter methylation level for renal KL promoter hypermethylation. Higher levels of KL promoter methylation were observed in renal tissue and PBMC in patients with CKD compared with controls (8.79±3.24 vs. 5.17±1.11%, P<0.001; 7.20±2.79 vs. 3.27±0.79%, P<0.001). In these patients, renal KL methylation level correlated inversely with renal KL immunostaining intensity (ρ=-0.794, P<0.001). Estimated glomerular filtration rate correlated inversely with renal and PBMC levels of KL promoter methylation (r=-0.829, P<0.001; r=-0.645, P<0.001), while tubulointerstistial fibrosis score correlated positively (ρ=0.826, P<0.001; ρ=0.755, P<0.001). PBMC KL promoter methylation level correlated positively with renal KL promoter methylation level in patients with CKD (r=0.787, P<0.001). In ROC curve, the area under curve was 0.964 (P<0.001) and the optimal cut-off value was 5.83% with a sensitivity of 93.8% and specificity of 86.7% to predict renal KL promoter hypermethylation. The degree of KL promoter methylation is associated with clinical and histological severity of CKD. PBMC KL promoter methylation level may act as a potential biomarker of renal KL promoter hypermethylation.

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Correlation between renal Klotho methylation level and renal Klotho immunostaining intensity in 47 patients with CKD.Immunostaining of consecutive kidney sections for Klotho in IgA nephropathy (A) and focal segmental glomerulosclerosis (B). Magnification, x200. Arrows indicate the detection of Klotho mainly in renal tubules. The level of renal Klotho methylation correlated inversely with renal Klotho staining score (C). mC%, percentage of methylated cytosines. ρ, Spearman correlation coefficient.
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pone-0079856-g004: Correlation between renal Klotho methylation level and renal Klotho immunostaining intensity in 47 patients with CKD.Immunostaining of consecutive kidney sections for Klotho in IgA nephropathy (A) and focal segmental glomerulosclerosis (B). Magnification, x200. Arrows indicate the detection of Klotho mainly in renal tubules. The level of renal Klotho methylation correlated inversely with renal Klotho staining score (C). mC%, percentage of methylated cytosines. ρ, Spearman correlation coefficient.

Mentions: Immunohistochemistry staining of KL was performed using a biotin-streptavidin-peroxidase method to examine correlation between the level of renal KL methylation and renal Klotho protein expression. This was performed in consecutive kidney sections obtained from patients with CKD. Representative pictures of KL immunostaining are shown in Figure 4. KL staining was detected mainly in the renal tubules. Renal KL methylation level correlated inversely with renal KL immunostaining intensity (ρ=-0.794, P<0.001) (Figure 4).


Elevated Klotho promoter methylation is associated with severity of chronic kidney disease.

Chen J, Zhang X, Zhang H, Lin J, Zhang C, Wu Q, Ding X - PLoS ONE (2013)

Correlation between renal Klotho methylation level and renal Klotho immunostaining intensity in 47 patients with CKD.Immunostaining of consecutive kidney sections for Klotho in IgA nephropathy (A) and focal segmental glomerulosclerosis (B). Magnification, x200. Arrows indicate the detection of Klotho mainly in renal tubules. The level of renal Klotho methylation correlated inversely with renal Klotho staining score (C). mC%, percentage of methylated cytosines. ρ, Spearman correlation coefficient.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3818221&req=5

pone-0079856-g004: Correlation between renal Klotho methylation level and renal Klotho immunostaining intensity in 47 patients with CKD.Immunostaining of consecutive kidney sections for Klotho in IgA nephropathy (A) and focal segmental glomerulosclerosis (B). Magnification, x200. Arrows indicate the detection of Klotho mainly in renal tubules. The level of renal Klotho methylation correlated inversely with renal Klotho staining score (C). mC%, percentage of methylated cytosines. ρ, Spearman correlation coefficient.
Mentions: Immunohistochemistry staining of KL was performed using a biotin-streptavidin-peroxidase method to examine correlation between the level of renal KL methylation and renal Klotho protein expression. This was performed in consecutive kidney sections obtained from patients with CKD. Representative pictures of KL immunostaining are shown in Figure 4. KL staining was detected mainly in the renal tubules. Renal KL methylation level correlated inversely with renal KL immunostaining intensity (ρ=-0.794, P<0.001) (Figure 4).

Bottom Line: Higher levels of KL promoter methylation were observed in renal tissue and PBMC in patients with CKD compared with controls (8.79±3.24 vs. 5.17±1.11%, P<0.001; 7.20±2.79 vs. 3.27±0.79%, P<0.001).Estimated glomerular filtration rate correlated inversely with renal and PBMC levels of KL promoter methylation (r=-0.829, P<0.001; r=-0.645, P<0.001), while tubulointerstistial fibrosis score correlated positively (ρ=0.826, P<0.001; ρ=0.755, P<0.001).The degree of KL promoter methylation is associated with clinical and histological severity of CKD.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Kidney Disease, Zhongshan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.

ABSTRACT
Klotho (KL) expression is down-regulated in the renal tissues of chronic kidney disease (CKD) animal models and patients with end-stage renal disease. The putative role of KL promoter hypermethylation in the progression of CKD remains unclear. The present study aimed to determine renal and peripheral blood mononuclear cells (PBMC) levels of KL promoter methylation and analyze their relationship with clinical and histological severity in patients with CKD. Using bisulfite pyrosequencing, renal and PBMC levels of KL promoter methylation were quantified in 47 patients with CKD. 47 nephrectomy specimens of patients with renal cell carcinoma and 48 PBMC specimens of healthy volunteers were used as renal tissue and PBMC controls, respectively. Renal expression of KL protein was assayed by immunohistochemistry staining. Receiver operating characteristic (ROC) curve was used to identify the optimal cut-off value of PBMC KL promoter methylation level for renal KL promoter hypermethylation. Higher levels of KL promoter methylation were observed in renal tissue and PBMC in patients with CKD compared with controls (8.79±3.24 vs. 5.17±1.11%, P<0.001; 7.20±2.79 vs. 3.27±0.79%, P<0.001). In these patients, renal KL methylation level correlated inversely with renal KL immunostaining intensity (ρ=-0.794, P<0.001). Estimated glomerular filtration rate correlated inversely with renal and PBMC levels of KL promoter methylation (r=-0.829, P<0.001; r=-0.645, P<0.001), while tubulointerstistial fibrosis score correlated positively (ρ=0.826, P<0.001; ρ=0.755, P<0.001). PBMC KL promoter methylation level correlated positively with renal KL promoter methylation level in patients with CKD (r=0.787, P<0.001). In ROC curve, the area under curve was 0.964 (P<0.001) and the optimal cut-off value was 5.83% with a sensitivity of 93.8% and specificity of 86.7% to predict renal KL promoter hypermethylation. The degree of KL promoter methylation is associated with clinical and histological severity of CKD. PBMC KL promoter methylation level may act as a potential biomarker of renal KL promoter hypermethylation.

Show MeSH
Related in: MedlinePlus