The controversy of klotho as a potential biomarker in chronic kidney disease.

Klotho is an identified longevity gene with beneficial pleiotropic effects on the kidney. Evidence shows that a decline in serum Klotho level occurs in early chronic kidney disease (CKD) and continues as CKD progresses. Klotho deficiency is associated with poor clinical outcomes and CKD mineral bone disorders (CKD-MBD). Klotho has been postulated as a candidate biomarker in the evaluation of CKD. However, the evidence for the clinical significance of the relationship between Klotho and kidney function, CKD stage, adverse kidney and/or non-kidney outcomes, and CKD-MBD remains inconsistent and in some areas, contradictory. Therefore, there is uncertainty as to whether Klotho is a potential biomarker in CKD; a general consensus regarding the clinical significance of Klotho in CKD has not been reached, and there is limited evidence synthesis in this area. To address this, we have systematically assessed the areas of controversy, focusing on the inconsistencies in the evidence base. We used a PICOM strategy to search for relevant studies and the Newcastle-Ottawa Scale scoring to evaluate included publications. We reviewed the inconsistent clinical findings based on the relationship of Klotho with CKD stage, kidney and/or non-kidney adverse outcomes, and CKD-MBD in human studies. Subsequently, we assessed the underlying sources of the controversies and highlighted future directions to resolve these inconsistencies and clarify whether Klotho has a role as a biomarker in clinical practice in CKD.

Association of Soluble Klotho Level with Adverse Outcomes in Patients on Maintenance Hemodialysis.

BACKGROUND: The predictive value of soluble Klotho (sKlotho) for adverse outcomes in patients on maintenance hemodialysis (MHD) is controversial. In this study, we aimed to clarify the potential association of sKlotho levels with adverse outcomes in this patient population. MATERIALS: A total of 211 patients on MHD were identified and stratified according to the median sKlotho level. Patients were followed up for adverse outcomes including cardiovascular (CV) morbidity and all-cause mortality. RESULTS: During the 36-month follow-up, 75 patients [51 CV events (including 16 CV deaths) and 40 deaths] experienced adverse outcomes. After stratification according to median sKlotho level, patients with a lower sKlotho level had a greater risk of CV events (38.2% vs. 19.5%, p = 0.006), all-cause mortality (28.4% vs. 11.6%, p = 0.003), and combined adverse outcomes (51.0% vs. 24.2%, p < 0.001). Similar observations were made from analyses using Kaplan-Meier survival curves. Cox regression analysis showed that a low sKlotho level was strongly correlated with CV morbidity [1.942 (1.030-3.661), p = 0.040)], all-cause mortality [2.073 (1.023-4.203), p = 0.043], and combined adverse outcomes [1.818 (1.092-3.026), p = 0.021] in fully adjusted models. CONCLUSIONS: The sKlotho level was an independent predictive factor of adverse outcomes including CV morbidity and mortality in patients on MHD.

The Prognostic Role of Klotho in Patients with Chronic Kidney Disease: A Systematic Review and Meta-analysis.

OBJECTIVE: The prognostic role of Klotho in patients with chronic kidney disease is still controversial. Therefore, we performed this meta-analysis to assess the relationship between the low sKlotho level and the risk of adverse kidney outcomes. MATERIALS AND METHODS: We systematically searched medical databases, such as PubMed, Embase, and the Cochrane Library, for eligible publications regarding the relationship between the low sKlotho level and risk of adverse kidney outcomes. The quality of included studies was assessed by using the Newcastle-Ottawa Scale. Combined hazard ratios (HRs) and its 95% confidence intervals (CIs) were calculated using a random- or fixed-effect model. Subgroup analysis was conducted with stratification by age, estimated glomerular filtration rate (eGFR), follow-up interval, region, and study quality. All data was analyzed by RevMan 5.3 analysis software. RESULTS: Eight cohort studies with 3586 participants from 3818 studies were included in our final analysis. Levels of sKlotho were significantly correlated with the eGFR, with a summary correlation coefficient r and 95% CI of 0.469 (0.226, 0.658). Additionally, low sKlotho levels were strongly associated with increased adverse kidney outcomes, and the pooled HR and its 95% CI were 1.64 (1.19, 2.26; P = 0.002), despite publication bias and statistical heterogeneity (I 2 = 52%, P = 0.07). Furthermore, this positive correlation was still observed in all of the subgroup analyses. However, heterogeneity was present in subgroup analyses stratified by the eGFR and follow-up interval. CONCLUSION: Levels of sKlotho are positively correlated with the eGFR, and low sKlotho levels are significantly associated with an increased risk of poor kidney outcomes. Therefore, sKlotho could be used as a novel biomarker for early diagnosis and prognostic assessment for patients with chronic kidney disease. Studies with a larger sample size and longer follow-up period are warranted to validate our results.

Plasma s-Klotho is related to kidney function and predicts adverse renal outcomes in patients with advanced chronic kidney disease.

To investigate whether the soluble Klotho (s-Klotho) level in patients with chronic kidney disease (CKD) is related to kidney function and whether a low s-Klotho level can predict adverse renal outcomes or CKD progression in patients with advanced CKD. 112 patients with CKD stages 3-5 and 30 healthy volunteers were enrolled. Blood samples were collected to measure serum creatinine, calcium, phosphorus, intact parathyroid hormone, and hemoglobin. s-Klotho and fibroblast growth factor 23 (FGF23) were determined by ELISA. We first conducted a cross-sectional study to investigate correlations between s-Klotho and estimated glomerular filtration rate (eGFR) and other parameters. Patients were then followed prospectively for 20.1±10.1 months according to s-Klotho median level until serum creatinine doubled, or initiation of renal replacement therapy, or death. s-Klotho levels inpatients with CKD were significantly lower than that in the control group. For patients with CKD, there were no differences in age distribution among subgroups. However, s-Klotho level differed significantly across CKD stages, and it was lower in the advanced CKD group compared with the moderate CKD group. Correlation analysis revealed that s-Klotho was positively associated with eGFR, but inversely associated with FGF23. During the follow-up of 20.1±10.1 months, patients with higher s-Klotho levels showed a reduced risk of kidney adverse outcomes, including serum creatinine doubling and initiation of renal replacement therapy. Cox regression analysis revealed that low s-Klotho was an independent risk factor for CKD progression. s-Klotho level was closely correlated with kidney function, further, low s-Klotho level could predict adverse kidney disease outcomes in patients with progressive CKD.

Klotho mitigates cyclosporine A (CsA)-induced epithelial-mesenchymal transition (EMT) and renal fibrosis in rats.

PURPOSE: Klotho deficiency is implicated in various kidney diseases, including renal fibrosis. The aim of this study was to investigate the effect of Klotho administration on epithelial-mesenchymal transition (EMT) and renal fibrosis induced by cyclosporine A (CsA) in rats. METHODS: CsA-induced renal fibrosis was established by oral administration of CsA (30 mg/kg) to rats on a low-salt diet for 28 days. Klotho was administered to rats by intraperitoneal injection. Renal pathological changes were evaluated by hematoxylin and eosin and Masson's trichrome staining. The EMT response was assessed by measuring the level of TGF-ß1, E-cadherin and α-SMA by immunohistochemistry and Western blot. RESULTS: Administration of CsA for 28 days induced renal damage, decreased Klotho expression and activated the EMT response (demonstrated as increased TGF-ß1 and α-SMA expression accompanied by decreased in E-cadherin expression). Treatment with Klotho significantly ameliorated pathological lesions of the kidney by modulating the expression of EMT-associated proteins in the kidney. CONCLUSIONS: Klotho inhibits CsA-induced EMT and renal fibrosis in rats. Klotho may serve as a therapeutic agent to minimize CsA-induced renal fibrosis.

[Relationship between selection of Pinus massoniana families and Folium Pini].

Based on variation of Pinus massoniana families, heritablility and correlation analysis, the contents of shikimic acid and procyanidine (heritability 0.90, 0.70), dry weight of single branch (heritability 0.60) and and leaf length (heritability 0.46) were screened out as quality, yield and harvest cost traits of Folium Pini, respectively. For the different medicinal application of Folium Pini, varied methods were chosen to estimate weight and construct index equation. Weight adjustment based.on equal emphasis were used as economic weight determining method to select the best families, and the index (accuracy 0. 936 4 and heritability 0. 881 6) obtained was a little better than that obtained by equal emphasis, and much better than that by restricted index. The superior families selected with adjustment weight and equal emphasis were No. 46, 43 and 28. Partial regression were used as economic weight determining method to select the best families,and the index obtained had the highest accuracy (0.941 5) , index heritability (0. 889 9) and the genetic gain of shikimic acid content. The superior families selected with this method were No. 46, 27 and 47. No. 46 was the best families with maximal economic benefit. Our study indicated that suitable method for estimate weight and construct index equation can be applied for better accuracy of superior families selection of P. massoniana.

Ameliorating effect of Klotho on endoplasmic reticulum stress and renal fibrosis induced by unilateral ureteral obstruction.

INTRODUCTION: Expression of Klotho is decreased and endoplasmic reticulum (ER) stress is activated in patients with chronic kidney disease. This study aimed to investigate the effect of Klotho protein on ER stress-related apoptosis and renal fibrosis in rates with unilateral ureteral obstruction (UUO). MATERIALS AND METHODS: Twenty-four rats were divided into the sham, UUO, and Klotho treatment groups. Renal interstitial fibrosis model was induced by UUO in the rats of the latter two groups. Soluble Klotho protein was injected into the abdominal cavity. Serum and kidney samples were collected 14 days after the UUO surgery for examination of renal injury and renal interstitial fibrosis using hematoxylin-eosin and Masson trichrome staining methods. The level of apoptotic cells was assessed by the terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Expression of 3 ER stress-related proteins including glucose-regulated protein 78, CCAAT/enhancer-binding protein homologous protein, and caspase-12 were measured. RESULTS: Kidney dysfunction, increased renal injury index, and aggravated renal fibrosis were documented in the UUO group. Expression of Klotho in the UUO rats was remarkably decreased (P < .05) and expression of all three ER stress-related proteins were significantly upregulated, accompanied by increasing numbers of apoptotic cells (P < .05). Soluble Klotho administration improved kidney function, ameliorated pathological changes, decreased expressions of ER-stress related-proteins, and reduced the number of apoptotic cells. CONCLUSION: Unilateral ureteral obstruction decreased Klotho expression and activated ER stress and related apoptosis. Klotho administration ameliorated UUO-induced ER stress, inhibited apoptotic process, and attenuated renal fibrosis.

Ginsenoside-Rg1 inhibits endoplasmic reticulum stress-induced apoptosis after unilateral ureteral obstruction in rats.

AIM: Endoplasmic reticulum (ER) stress and unfolded protein response (UPR) are implicated in many fibrotic diseases, including renal fibrosis. Whether Ginsenoside-Rg1 (G-Rg1) could attenuate renal fibrosis via suppression of ER stress and UPR has not been reported. The aim of this study was to explore the effect of G-Rg1 on ER stress and UPR-induced apoptosis in kidneys with unilateral ureteral obstruction (UUO) rat model. METHODS: Twenty-four male Sprague-Dawley rats were randomly divided into control group, model group and G-Rg1 treatment group. G-Rg1 was administered to rats by intraperitoneal injection. Renal interstitial fibrosis in the model group was developed by UUO in rats. Renal function was estimated by the levels of serum creatinine (Scr) and blood urea nitrogen (BUN). Renal pathological damage was evaluated by hematoxylin and eosin (HE) and Masson's trichrome staining. The ER stress was assessed with glucose-regulated protein (GRP) 78 expression, and the proapoptotic response was detected with CCAAT/enhancer-binding protein homologous protein (CHOP) and caspase-12 expressions by Western Blot. The number of apoptotic cells was determined by Terminal-deoxynucleotidyl Transferase Mediated Nick End Labeling (TUNEL) analysis. RESULTS: UUO for 14 days aggravated renal function, renal damage and renal interstitial fibrosis, activated ER stress response (induction of GRP78 protein), enhanced the proapoptotic response (increase in CHOP and caspase-12 proteins) and increased the number of apoptotic cells (shown by the TUNEL assay). Treatment with G-Rg1 significantly ameliorates the renal pathological lesions and decreases expressions of ER stress-associated proteins and the level of apoptotic cells in kidneys. CONCLUSION: G-Rg1 suppresses renal cell apoptotic and fibrotic process partly through inhibition of ERS- and UPR-related apoptotic pathway in the kidneys after UUO.

A randomized clinical trial comparing prophylactic upper versus whole-neck irradiation in the treatment of patients with node-negative nasopharyngeal carcinoma.

BACKGROUND: This study sought to compare the clinical outcomes of upper versus whole-neck prophylactic irradiation in the treatment of patients with node-negative nasopharyngeal carcinoma (NPC). METHODS: Between November 2005 and June 2012, 301 patients with node-negative NPC were randomly assigned to receive primary plus prophylactic upper neck irradiation (UNI, 153 patients) or primary plus whole-neck irradiation (WNI, 148 patients). Patients in both groups received irradiation to the primary tumor and the upper neck nodal regions, and patients in the WNI group also received irradiation to the lower neck. The main endpoint of the study was to compare the lower neck control rate between the 2 groups. RESULTS: With a median follow-up period of 39 months (range, 6-84 months), no patient in either group had a cervical node relapse. The overall survival at 3 years was 89.5% (95% confidence interval [CI] = 84.1%-95.0%) in the UNI group and 87.4% (95% CI = 81.4%-93.5%) in the WNI group (hazard ratio [HR] = 0.866, 95% CI = 0.41-1.82; P = .70). The 3-year relapse-free survival rate was 89.8% and 89.3% (95% CI = 84.2%-95.3% and 83.7%-94.8%, HR = 0.914, 95% CI = 0.42-2.00; P = .82), and the 3-year metastasis-free survival rate was 91.7% and 90.9% (95% CI = 87.0%-96.5% and 85.7%-96.1%) for the UNI and WNI groups, respectively (HR = 1.007, 95% CI = 0.44-2.32; P = .99). CONCLUSIONS: Prophylactic upper neck irradiation is sufficient for patients with node-negative NPC.