Klotho Levels Research Articles

Association of Klotho with physical performance and frailty in middle-aged and older adults: A systematic review.

Ageing is an inevitable process of physical deterioration that impairs functional autonomy and quality of life, becoming a public health issue. Since the percentage of people over 60years is increasing worldwide, the use of easily detectable biomarkers of ageing is a relevant tool for monitoring of the ageing process and treatment. Among them, Klotho, an ageing suppressor gene because its deficiency leads to ageing like phenotype, seems particularly promising. This systematic review includes the last 10years clinical studies that evaluated the association between plasma Klotho and body composition, physical performance and frailty in both sedentary and active middle-aged and older adults. Sixteen studies have been found: nine regarding the association between Klotho and body composition, two the association of Klotho and frailty and finally five concerning the effects of physical activity on Klotho. The results of these studies, albeit with some exceptions, point out that Klotho is positively associated with muscle strength and negatively with osteoporosis, frailty, disability and mortality while physical activity generally increases Klotho levels. Moreover, even if there are still few clinical studies, Klotho might be positively associated with bone mineral density, muscle strength, longevity, mobility and robustness during ageing.

Analysis of Klotho Protein Level in Patients with Myocardial Infarction and Concurrent Chronic Obstructive Pulmonary Disease with Different Manifestations

The objective: to compare the level of Klotho protein in patients with myocardial infarction (M I) and concurrent chronic obstructive pulmonary disease (COPD) and patients with COPD only with consideration of specific manifestations of COPD (severity of symptoms and risk of exacerbations).Subjects and Methods. 144 patients were examined and divided into the following groups: MI + COPD Group - patients with MI and concurrent COPD (60 patients), COPD Group - patients with COPD (54 patients) and HI Group - somatically healthy individuals (30 people). The patients were divided into subgroups (A, B, C, D) according to the GOLD 2019 classification. Enzyme immunoassay was used to test the level of Klotho.Results. A statistically significant lower level of Klotho was detected in patients in MI + COPD Group compared to COPD Group and healthy individuals. Patients in the subgroups with severe symptoms (B and D) in both the COPD and MI + COPD Groups had statistically significantly lower levels of Klotho compared to those in the subgroups with no symptoms (A and C). Among patients with MI + COPD in subgroups A, B, C, D, the Kloto level was statistically significantly lower versus the patients of the corresponding subgroups in COPD Group. The lowest level of Klotho was detected in MI + COPD and COPD Groups in patients of subgroup D, that was in patients with severe symptoms and frequent exacerbations of COPD. The data obtained were confirmed by correlation analysis results. It was found that in MI + COPD and COPD Groups, the level of Klotho had a negative correlation with both the severity of symptoms and number of COPD exacerbations. Correlations were the strongest between the level of Klotho and parameters characterizing the severity of COPD symptoms.

Белок Klotho и фактор роста фибробластов FGF23 как маркеры хронической болезни почек

Хроническая болезнь почек (ХБП) является глобальной проблемой общественного здравоохранения в мире. Исследования ученых направлены на поиски новых биомаркеров ХБП. Такими биомаркерами являются растворимый белок α-Klotho и фактор роста фибробластов FGF23. Показано, что экспрессия белка Klotho уменьшается параллельно с прогрессированием ХБП и достигает низких или неопределяемых значений в терминальной стадии заболевания почек. В отличие от Klotho фактор роста фибробластов FGF23 повышается на ранних стадиях ХБП и служит предиктором неблагоприятного клинического исхода. Уровни белка Klotho и FGF23 являются ранними, чувствительными и специфичными биомаркерами при ХБП и имеют диагностичеcкую ценность для прогнозирования осложнений при заболевании почек.

Implications of Klotho Protein for Managing Kidney Disease - an Emerging Role in Therapeutics and Molecular Medicine.

Acute Kidney Injury (AKI) and Chronic Kidney Disease (CKD) are a growing public health problem. There is a paucity of sensitive biomarkers to detect AKI, early CKD, and ameliorate extra-renal complications. Klotho protein, detected mainly in the kidneys, regulates renal health and functions as a co-receptor for fibroblast growth factor 23 (FGF-23) signaling. It is now coming to be known for its extreme pleiotropic actions. These include cytoprotection via anti-oxidation, anti-senescence, anti-apoptosis, renoprotective effects, promotion of angiogenesis and vascularisation, inhibition of fibrogenesis, and stem cell preservation. Emerging clinical studies suggest kidney damage to be a perpetual state of renal Klotho deficiency. In AKI, Klotho levels in plasma and/or urine possibly will serve as an initial biomarker for kidney parenchymal injury. In CKD, Klotho levels may also be an indicator of early disease as well as predict the rate of progression. Earlier studies using ELISA as a technique reveal a correlation between plasma Klotho, eGFR, serum creatine, and Blood Urea Nitrogen (BUN) levels. Thereby preventing the decline of Klotho levels by various mechanisms can retard CKD advancement and improve renal function. Substantial data indicate Klotho can be therapeutically included as an individualized regimen for managing CKD patients. Considerable research is required in investigating the role of soluble Klotho as a biomarker in patients with different types and severity of kidney diseases, which will be highlighted in our review.

Lumbar spine abnormalities in patients with obstructive sleep apnoea

Previous studies suggested cervical spondylosis as a risk factor for development of obstructive sleep apnoea (OSA). We aimed to assess lumbar disc degeneration in patients with OSA and correlate the findings with symptoms and disease severity. Twenty-seven patients with OSA and 29 non-OSA controls underwent sleep studies and lumbar magnetic resonance imaging (MRI), and completed the Epworth Sleepiness Scale and the 24-item Roland‐Morris Disability Questionnaire (RMDQ) questionnaires. Plasma klotho was determined with enzyme-linked immunosorbent assay. Patients with OSA had higher number of disc bulges (4.6 ± 3.7 vs. 1.7 ± 2.5, p < 0.01) and anterior spondylophytes (2.7 ± 4.2 vs. 0.8 ± 2.1, p < 0.01), increased disc degeneration (total Pfirrmann score 16.7 ± 4.7 vs. 13.2 ± 4.1, p < 0.01) and vertebral fatty degeneration (7.8 ± 4.7 vs. 3.8 ± 3.7, p < 0.01). There was no difference in the RMDQ score (0/0–3.5/ vs. 0/0–1/, p > 0.05). Markers of OSA severity, including the oxygen desaturation index and percentage of total sleep time spent with saturation < 90% as well as plasma levels of klotho were correlated with the number of disc bulges and anterior spondylophytes (all p < 0.05). OSA is associated with lumbar spondylosis. Our study highlights the importance of lumbar imaging in patients with OSA reporting lower back pain.

Klotho as a biomarker of subclinical atherosclerosis in patients with moderate to severe chronic kidney disease

Chronic kidney disease (CKD) has been associated with a higher risk of cardiovascular disease (CVD). CKD patients present a decrease in the levels of the protein Klotho that accompanies the decrease in kidney function. This protein has been related to protective effects against CVD. However, it is unclear whether circulating Klotho, and its expression in peripheral blood cells (PBCs) are also associated with subclinical atherosclerosis in CKD. The present study aimed to study the relationship between Klotho and subclinical atherosclerosis in a population of patients with moderate to severe CKD. We determined the serum levels and gene expression in PBCs levels of Klotho and three inflammatory cytokines in 103 patients with CKD and investigated their relationship with two surrogate markers of subclinical atherosclerotis: ankle-brachial index (ABI) and carotid intima-media thickness (CIMT). Patients with subclinical atherosclerosis presented lower serum and PBCs expression levels of Klotho. Both variables were associated with the presence of subclinical atherosclerosis, being directly related with ABI and inversely with CIMT (P < 0.0001 for both). Multiple regression analysis demonstrated that both variables were significant determinants for ABI (adjusted R2 = 0.511, P < 0.0001) and CIMT (adjusted R2 = 0.445, P < 0.0001), independently of traditional and emergent cardiovascular risk factors. Moreover, both constituted protective factors against subclinical atherosclerosis [OR: 0.993 (P = 0.002) and 0.231 (P = 0.025), respectively]. Receiver operating characteristic analysis pointed to the utility of serum Klotho (area under the curve [AUC]: 0.817, 95% CI: 0.736–0.898, P < 0.001) and its gene expression in PBCs (AUC: 0.742, 95% CI: 0.647–0.836, P < 0.001) to distinguish subclinical atherosclerosis. The reductions in serum and PBCs expression levels of Klotho in CKD patients are independently associated with the presence of for subclinical atherosclerosis. Further research exploring whether therapeutic approaches to maintain or elevate Klotho could reduce the impact of CVD in CKD patients is warranted.

Protective effect of soluble Klotho in pediatric patients undergoing cardiac surgery with cardiopulmonary bypass support-A pilot study.

The Klotho protein family plays important roles in several metabolic pathways. Soluble Klotho has been recently put forward as an antiaging protein, demonstrating renal and cardiovascular protective traits. Cardiopulmonary bypass (CPB) support during cardiac surgery has been implicated in several adverse outcomes in pediatric and adult patients. Our goal was to assess whether serum Klotho levels can be used to predict outcomes in children undergoing cardiac surgery with CPB due to congenital heart defects (CHDs). This prospective study was conducted on pediatric patients admitted to two Pediatric Cardiac Intensive Care Units, between 2012 and 2018. All patients were born with CHD and underwent corrective surgery with CPB. Sequential blood samples were analyzed by enzyme-linked immunosorbent assay for soluble Klotho levels at baseline, 2, 6, and 24 h after surgery. The association between Klotho levels and several demographic, intraoperative, and postoperative clinical and laboratory parameters was studied. Twenty-nine children undergoing cardiac surgery with CPB support were included. Serum Klotho levels were shown to significantly decrease 2 h after surgery and increase to baseline levels after 6 h (p < .001 and p < .05, respectively). Patients with low Klotho levels 2 h after surgery were at a 32-fold higher risk for developing postoperative complications (p = .015, odds ratio < 0.03). Moreover, Klotho levels at each of the four time points were lower in patients who developed postoperative complications. Cardiac surgery with CPB results in a significant decrease of serum Klotho levels 2 h after surgery in pediatric patients with CHDs, which can be used to predict development of postoperative complications in this patient population.

Constitutive transgenic α-Klotho overexpression enhances resilience to and recovery from murine acute lung injury.

Normal lungs do not express α-Klotho (Klotho) protein but derive cytoprotection from circulating soluble Klotho. It is unclear whether chronic supranormal Klotho levels confer additional benefit. To address this, we tested the age-related effects of modest Klotho overexpression on acute lung injury (ALI) and recovery. Transgenic Klotho-overexpressing (Tg-Kl) and wild-type (WT) mice (2 and 6 mo old) were exposed to hyperoxia (95% O2; 72 h; injury; Hx) then returned to normoxia (21% O2; 24 h; recovery; Hx-R). Control mice were kept in normoxia. Renal and serum Klotho, lung histology, and bronchoalveolar lavage fluid oxidative damage markers were assessed. Effects of hyperoxia on Klotho release were tested in human embryonic kidney cells stably expressing Klotho. A549 lung epithelial cells transfected with Klotho cDNA or vector were exposed to cigarette smoke; lactate dehydrogenase and double-strand DNA breaks were measured. Serum Klotho decreased with age. Hyperoxia suppressed renal Klotho at both ages and serum Klotho at 2 mo of age. Tg-Kl mice at both ages and 2-mo-old WT mice survived Hx-R; 6-mo-old Tg-Kl mice showed lower lung damage than age-matched WT mice. Hyperoxia directly inhibited Klotho expression and release in vitro; Klotho transfection attenuated cigarette smoke-induced cytotoxicity and DNA double-strand breaks in lung epithelial cells. Young animals with chronic high baseline Klotho expression were more resistant to ALI. Chronic constitutive Klotho overexpression in older Tg-Kl animals attenuated hyperoxia-induced lung damage and improves survival and short-term recovery despite an acute reduction in serum Klotho during injury. We conclude that chronic enhancement of Klotho expression increases resilience to ALI.

KLOTHO gene promoter methylation in the vasculature is related to inflammation in human atherosclerosis

Background and Aims: Klotho (KL) deficiency have been related to the appearance and progression of atherosclerotic damage associated with cardiovascular diseass (CVD). Methylation of CpG islands in the promoter region is one of the most studied mechanisms that regulate KL expression. We propose that this mechanism participates in the regulation of vascular KL expression and contributes to the deficiency in vascular KL levels observed in CVD. Moreover, we determined the influence of inflammatory components in the methylation status of KL promoter.

Role of Klotho in Hyperglycemia: Its Levels and Effects on Fibroblast Growth Factor Receptors, Glycolysis, and Glomerular Filtration.

Hyperglycemic conditions (HG), at early stages of diabetic nephropathy (DN), cause a decrease in podocyte numbers and an aberration of their function as key cells for glomerular plasma filtration. Klotho protein was shown to overcome some negative effects of hyperglycemia. Klotho is also a coreceptor for fibroblast growth factor receptors (FGFRs), the signaling of which, together with a proper rate of glycolysis in podocytes, is needed for a proper function of the glomerular filtration barrier. Therefore, we measured levels of Klotho in renal tissue, serum, and urine shortly after DN induction. We investigated whether it influences levels of FGFRs, rates of glycolysis in podocytes, and albumin permeability. During hyperglycemia, the level of membrane-bound Klotho in renal tissue decreased, with an increase in the shedding of soluble Klotho, its higher presence in serum, and lower urinary excretion. The addition of Klotho increased FGFR levels, especially FGFR1/FGFR2, after their HG-induced decrease. Klotho also increased levels of glycolytic parameters of podocytes, and decreased podocytic and glomerular albumin permeability in HG. Thus, we found that the decrease in the urinary excretion of Klotho might be an early biomarker of DN and that Klotho administration may have several beneficial effects on renal function in DN.

Involvement of Sirtuins and Klotho in Cardioprotective Effects of Exercise Training Against Waterpipe Tobacco Smoking-Induced Heart Dysfunction.

Despite its negative effect on the cardiovascular system, waterpipe smoking (WPS) is currently popular worldwide, especially among youth. This study investigated the effects of moderate endurance exercise on heart function of rats exposed to WPS and its possible mechanism. The animals were randomly divided into four groups: control group (CTL), the exercise group (Ex) which trained for 8 weeks, the waterpipe tobacco smoking group (S) exposed to smoke inhalation (30 min per day, 5 days each week, for 8 weeks), and the group that did exercise training and received waterpipe tobacco smoke inhalation together (Ex + S). One day after the last session of Ex and WPS, cardiac pressures and functional indices were recorded and calculated. The levels of SIRT1, SIRT3, Klotho, Bax, and Bcl-2 in the serum and heart, the expression of phosphorylated GSK3β of heart tissue, and cardiac histopathological changes were assessed. WPS reduced systolic pressure, +dP/dt max, -dP/dt max, and heart contractility indices (P < 0.001 vs. CTL) and increased cardiac tissue lesions (P < 0.05 vs. CTL) and end diastolic pressure and Tau index (P < 0.001 vs. CTL) of the left ventricle. Exercise training normalized the left ventricular end diastolic pressure, +dP/dt max, and contractility index. Also, exercise improved the levels of SIRT1, SIRT3, Klotho, and Bcl-2 and reduced Bax level in the heart. The findings showed that WPS causes left ventricular dysfunction. Moderate exercise prevented WPS-induced heart dysfunction partly through its anti-apoptotic features and activation of the sirtuins and Klotho pathways.

The Effects of Cholecalciferol Supplementation on FGF23 and α-Klotho in Hemodialysis Patients With Hypovitaminosis D: A Randomized, Double-Blind, Placebo-Controlled Trial

Vitamin D-fibroblast growth factor-23 (FGF-23)-klotho forms an axis that takes part at least in cardiovascular complications in patients with chronic kidney disease. This study aimed to assess the effects of cholecalciferol supplementation on FGF23 and α-klotho in patients with hypovitaminosis D requiring hemodialysis. In a single-center, parallel-arm, randomized, double-blind, placebo-controlled trial, 86 patients with hypovitaminosis D requiring hemodialysis were enrolled. The patients were randomized into 2 groups (n=43 each) to receive either 50,000 IU of cholecalciferol or placebo every week for 12weeks. Accordingly, the serum levels of FGF23 and klotho were measured by ELISA and compared between both groups. Serum 25OH(D) levels increased in participants who received cholecalciferol supplementation compared with participants who received placebo (P=.006). In addition, serum FGF23 decreased and α-klotho levels increased in the supplemented group compared with placebo. However, the before-after differences between cholecalciferol supplement and placebo were significant only for α-klotho (P=.035). These effects were not accompanied by changes in the levels of phosphate, total and ionized calcium, and intact parathyroid hormone. Cholecalciferol supplementation of 50,000 IU for 12weeks increases α-klotho levels in the serum of kidney failure patients undergoing hemodialysis. This may suggest that patients receiving maintenance hemodialysis can benefit from using cholecalciferol supplementation and increase in serum α-klotho levels.

Post-kidney transplant soluble Klotho levels are determined by pretransplant soluble Klotho levels in both living donors and recipients.

Soluble Klotho (sKl), the free form of membrane-bound Klotho predominantly expressed in the kidney, is detectable in serum and may have multiple pleiotropic effects. Patients with end-stage kidney disease are possibly sKl deficient, and kidney transplantation is the treatment of choice in these patients; however, little is known about changes in posttransplant sKl level and the factors influencing these changes. We conducted a prospective longitudinal study to examine changes in posttransplant sKl level in recipients for 12months after living-donor kidney transplantation and analyzed correlations between posttransplant changes in sKl levels and various influencing factors in both recipients and donors. 29 kidney transplant recipients and their living donors were included for analysis. The results showed that sKl levels transiently decreased at 1week posttransplant but progressively increased thereafter for 12months. Multivariable linear regression analysis showed that body surface area-adjusted donor sKl levels were associated with posttransplant increases in recipient sKl levels at 12months. In addition, pretransplant recipient sKl levels and body surface area-adjusted donor sKl levels were identified as an independent predictor of 12-month posttransplant sKl levels. Pretransplant sKl levels in both kidney recipients and living donors are a strong determinant of sKl levels after kidney transplantation.

Prognostic Value of Serum Soluble Klotho and Fibroblast Growth Factor-23 in Multiple Myeloma Patients.

Multiple myeloma is the plasma cell malignancy in which bone involvement is common. The Fibroblast growth factor-23 (FGF-23)/Klotho pathway plays a major role in mineral metabolism that FGF-23 is mineralization inhibitory. Klotho also has anti-apoptotic and anti-tumor effects by acting as a tumor suppressor gene. There is a negative correlation between serum FGF-23 and serum soluble Klotho (sKL) levels. As such, there can be considerable interest in investigating sKL and FGF-23 as a biomarker in patients with MM. We used an enzyme-linked immunosorbent assay to measure serum FGF-23 and sKL levels in 55 newly diagnosed MM patients and 23 healthy controls. We determined significantly high serum FGF-23 and low serum sKL levels in MM patients when compared to healthy controls. Serum sKL levels correlated negatively with a p53 positive mutation status, with high ISS, elevated lactate dehydrogenase, C-reactive protein, Beta-2 microglobulin levels. Serum FGF-23 levels are associated negatively with serum phosphorus and positively only light chains and p53 mutation. Patients with high serum FGF-23 levels had significantly shorter median overall survival than those with low serum FGF-23 levels (p = 0.008). Additionally, low sKL levels were related to decreased overall survival, but they didn't reach statistically significant (p = 0.072). There is a significant correlation between low serum sKL, high FGF-23 levels, and known prognostic factors in MM patients. We conclude that low sKL and high FGF-23 levels are a probable prognostic biomarker for poor MM patient outcomes.

Hemodiafiltration Is Associated With Reduced Inflammation and Increased Bone Formation Compared With Conventional Hemodialysis in Children: The HDF, Hearts and Heights (3H) Study

BackgroundPatients on dialysis have a high burden of bone-related comorbidities, including fractures. We report a post hoc analysis of the prospective cohort study HDF, Hearts and Heights (3H) to determine the prevalence and risk factors for chronic kidney disease-related bone disease in children on hemodiafiltration (HDF) and conventional hemodialysis (HD).MethodsThe baseline cross-sectional analysis included 144 children, of which 103 (61 HD, 42 HDF) completed 12-month follow-up. Circulating biomarkers of bone formation and resorption, inflammatory markers, fibroblast growth factor-23, and klotho were measured.ResultsInflammatory markers interleukin-6, tumor necrosis factor-α, and high-sensitivity C-reactive protein were lower in HDF than in HD cohorts at baseline and at 12 months (P < .001). Concentrations of bone formation (bone-specific alkaline phosphatase) and resorption (tartrate-resistant acid phosphatase 5b) markers were comparable between cohorts at baseline, but after 12-months the bone-specific alkaline phosphatase/tartrate-resistant acid phosphatase 5b ratio increased in HDF (P = .004) and was unchanged in HD (P = .44). On adjusted analysis, the bone-specific alkaline phosphatase/tartrate-resistant acid phosphatase 5b ratio was 2.66-fold lower (95% confidence interval, −3.91 to −1.41; P < .0001) in HD compared with HDF. Fibroblast growth factor-23 was comparable between groups at baseline (P = .52) but increased in HD (P < .0001) and remained unchanged in HDF (P = .34) at 12 months. Klotho levels were similar between groups and unchanged during follow-up. The fibroblast growth factor-23/klotho ratio was 3.86-fold higher (95% confidence interval, 2.15–6.93; P < .0001) after 12 months of HD compared with HDF.ConclusionChildren on HDF have an attenuated inflammatory profile, increased bone formation, and lower fibroblast growth factor-23/klotho ratios compared with those on HD. Long-term studies are required to determine the effects of an improved bone biomarker profile on fracture risk and cardiovascular health.

The Effect of Six Weeks of Moderate-Intensity Endurance Training on Serum Levels of Klotho and Expression of the Fibroblast-23 Growth Factor Gene (FGF23) in the Hearts of Diabetic Rats: An Experimental Study

The Effect of Six Weeks of Moderate-Intensity Endurance Training on Serum Levels of Klotho and Expression of the Fibroblast-23 Growth Factor Gene (FGF23) in the Hearts of Diabetic Rats: An Experimental Study

Nephroprotective effect of dapagliflozin in type 2 diabetes mellitus: A potential role of Klotho protein

Abstract. The present study aimed to investigate the dynamics of clinical and laboratory parameters and serum Klotho protein level in patients with diabetic kidney disease using nephroprotective therapy combined with an inhibitor of the sodium-glucose cotransporter 2 (SGLT2) dapagliflozin.&#x0D; Methods. A total of 76 type 2 diabetic patients with diabetic nephropathy (DN) were examined in this prospective study. Control group - 20 healthy subjects. 53 patients received a standard course of treatment, which included metformin, renin-angiotensin-aldosterone system blockers and statins. In addition to standard therapy, 23 patients have been prescribed the SGLT2 inhibitor dapagliflozin 10 mg per day. The treatment follow-up period was six months. Klotho concentration was determined by an enzyme-linked immunosorbent assay.&#x0D; Results. The development of DN in type 2 diabetic patients was accompanied by a significant decrease in soluble Klotho protein in comparison with controls and patients without nephropathy. During follow-up, Klotho protein level was changed significantly in the group of DN patients with albuminuria. Standard therapy resulted in Klotho concentration increase by 14% compared to pre-treatment values; a more demonstrative increase in the Klotho level was found in the dapagliflozin group (almost 23%).&#x0D; Conclusions. SGLT2 inhibitor treatment resulted in a significant increase of pleiotropic serum protein Klotho in patients with type 2 diabetes and diabetic kidney disease.

Uremic Cardiomyopathy

Chronic Kidney Disease (CKD) affects approximately 10% of the general population. CKD itself is a risk factor for cardiovascular mortality and morbidity. Large epidemiological studies have clearly established a clear relationship between severity of CKD and cardiovascular event rates. Sudden cardiac death accounts for approximately 40% mortality in dialysis patients and it is usually secondary to an underlying cardiomyopathy, with left ventricular hypertrophy mostly evident on echocardiography. Several risk factors play an important role in pathogenesis of uremic cardiomyopathy including vitamin D deficiency, secondary hyperparathyroidism, phosphate retention, increased FGF23 and decreased Klotho levels. The mortality due to cardiovascular events in early stage CKD is relatively higher in comparison to progression to ESRD, so early diagnosis and treatment with dialysis should be focused.

The levels of inflammatory biomarkers in hemodialysis and peritoneal dialysis patients.

In this study, we aimed to determine fibroblast growth factor 23, soluble alpha klotho, osteocalcin, indoxyl sulphate, sclerostin, Procollagen 1 N Terminal Propeptide, and beta-CrossLaps levels in hemodialysis and peritoneal dialysis patients, and to compare the levels of these markers among hemodialysis and peritoneal dialysis patients, as well as healthy individuals. The study included 30 hemodialysis and 23 peritoneal dialysis patients who were followed-up for at least six months at the Sakarya University Hospital, besides 30 healthy volunteers. The participants were divided into three groups with similar characteristics in terms of age, gender and body mass index. Fibroblast growth factor 23, soluble alpha klotho, indoxyl sulphate, beta-CrossLaps, and Procollagen 1 N Terminal Propeptide levels were significantly higher in patients of both the hemodialysis and peritoneal dialysis groups than in the healthy volunteers' group. There was no difference in levels of these molecules between hemodialysis and peritoneal dialysis groups. Fibroblast growth factor 23, sclerostin, indoxyl sulphate, beta-CrossLaps, and Paclitaxel-induced neuropathic pain levels were higher in patients of both groups as inflammatory markers. In our study, we found higher soluble alpha klotho levels in patients of both groups than in the healthy volunteers' group, suggesting that blood soluble alpha klotho levels may not correlate with renal klotho levels.

MO440KLOTHO AS A BIOMARKER OF SUBCLINICAL CARDIOVASCULAR DISEASE IN CHRONIC KIDNEY DISEASE: A PROOF-OF-CONCEPT STUDY*

Abstract Background and Aims Cardiovascular disease (CVD) is the major cause of mortality among chronic kidney disease (CKD) patients. Reductions in serum Klotho levels are related to the prevalence of CVD in CKD patients. However, it is unclear whether circulating Klotho, and its expression in peripheral blood cells (PBCs), are associated with subclinical atherosclerotic cardiovascular disease (sCVD) in these subjects. In this proof-of-concept study, we analyzed in a group of CKD patients the relationship between Klotho and two markers of sCVD: ankle-brachial index (ABI) and carotid intima-media thickness (CIMT). Method Gene expression in PBCs and serum levels of Klotho and inflammatory cytokines (TNF, IL6 and IL10) were measured in 103 CKD patients (stages 3-4), older than 18 years of age, and without known atherosclerotic cardiovascular disease. Biochemical data were obtained following standardized clinical methods. The presence of sCVD was defined as ABI &amp;lt; 0.9 and/or CIMT ≥ 0.9 mm. Patients with ABI values ≥ 1.3 were excluded. Results Patients with sCVD presented lower serum and PBCs expression levels of Klotho (P&amp;lt;0.001 for both). Stratified analysis showed that upper tertiles of both serum and PBCs expression levels of Klotho presented significantly higher ABI (P&amp;lt;0.001 for both Klotho determinations) and lower CIMT (P&amp;lt;0.001 for serum levels and P&amp;lt;0.01 for KL expression in PBCs), which resulted in a lower prevalence of sCVD (P&amp;lt;0.001 for both determinations of Klotho). Correlation analysis showed that both serum and PBCs mRNA Klotho levels were positively correlated with ABI (r=0.556, P&amp;lt;0.0001; and r=0.373, P&amp;lt;0.0001, respectively) and inversely correlated with CIMT (r=-0.541, P&amp;lt;0.0001; and r=-0.437, P&amp;lt;0.0001, respectively). Among inflammatory markers, only serum IL6 levels presented significant associations with sCVD, being inversely related with ABI (r=-0.568, P&amp;lt;0.0001) and positively associated with CIMT (r=0.558, P&amp;lt;0.0001). Multiple regression analysis with ABI and CIMT as dependent variables demonstrated that both Klotho variables, together with serum IL6, were positively and significantly associated with ABI (adjusted R2=0.511, P&amp;lt;0,0001) and CIMT (adjusted R2=0.445, P&amp;lt;0,0001) values, independently of traditional and emergent cardiovascular risk factors. Multivariate logistic regression, using the presence/absence of sCVD as the dependent variable, showed that circulating Klotho, and its expression in PBCs constituted independent protective factors for sCVD [OR (95% CI): 0.993 (P=0.002) and 0.231 (P=0.025), respectively]. Receiver operating curve (ROC) analysis pointed to the prognostic ability for sCVD of serum Klotho (area under the curve [AUC]: 0.817, 95% CI: 0.736–0.898, P&amp;lt;0.001) and its gene expression in PBCs (AUC: 0.742, 95% CI: 0.647–0.836, P&amp;lt;0.001). Conclusion The reductions in serum soluble and PBCs expression levels of Klotho in CKD patients are independently associated with the presence of sCVD. Further research exploring whether therapeutic approaches to maintain or elevate the Klotho level could reduce the impact of CVD in CKD patients is warranted.