osteoprotegerin and Renal-Insufficiency--Chronic

In the course of chronic kidney disease (CKD), alterations in the bone-vascular axis augment the risk of bone loss, fractures, vascular and soft tissue calcification, left ventricular hypertrophy, renal and myocardial fibrosis, which markedly increase morbidity and mortality rates. A major challenge to improve skeletal and cardiovascular outcomes in CKD patients requires a better understanding of the increasing complex interactions among the main modulators of the bone-vascular axis. Serum parathyroid hormone (PTH), phosphorus (P), calcium (Ca), fibroblast growth factor 23 (FGF23), calcidiol, calcitriol and Klotho are involved in this axis interact with RANK/RANKL/OPG system and the Wnt/β-catenin pathway. The RANK/RANKL/OPG system controls bone remodeling by inducing osteoblast synthesis of RANKL and downregulating OPG production and it is also implicated in vascular calcification. The complexity of this system has recently increased due the discovery of LGR4, a novel RANKL receptor involved in bone formation, but possibly also in vascular calcification. The Wnt/β-catenin pathway plays a key role in bone formation: when this pathway is activated, bone is formed, but when it is inhibited, bone formation is stopped. In the progression of CKD, a downregulation of the Wnt/β-catenin pathway has been described which occurs mainly through the not coincident elevations of sclerostin, Dickkopf1 (Dkk1) and the secreted Frizzled Related Proteins (sFRPs). This review analyzes the interactions of PTH, P, Ca, FGF23, calcidiol, calcitriol and Klotho with the RANKL/RANKL/OPG system and the Wnt/β-catenin, pathway and their implications in bone and cardiovascular disorders in CKD.

Topics: Bone and Bones; Bone Remodeling; Catenins; Fibroblast Growth Factor-23; Humans; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Renal Insufficiency, Chronic

Studies have shown inconsistent results regarding the association between osteoprotegerin (OPG) concentration and cardiovascular mortality in patients with chronic kidney disease (CKD). This systematic review and meta-analysis aims to investigate the association between OPG concentration and cardiovascular mortality in patients with CKD.. Between January 1970 and February 2020, the PubMed, EMBASE, and Cochrane Library databases were searched for eligible studies investigating the association between OPG concentration and cardiovascular mortality in patients with CKD. Pooled hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) were calculated using random effects models.. In total, 10 studies comprising 2,120 patients (including 1,723 receiving dialysis) with CKD were included. The included studies were considered to be of fair to high quality. Patients in the highest OPG concentration group had a significantly higher risk of cardiovascular mortality (4 studies; adjusted HR, 2.05; 95% CI, 1.39-3.00) than patients in the low OPG concentration group. An increase of 1 pmol/L in OPG concentration was associated with a 4% increased risk of cardiovascular mortality (6 studies; adjusted HR, 1.04; 95% CI, 1.02-1.07).. Elevated OPG concentrations are associated with an increased risk of cardiovascular death in patients with CKD.

Topics: Cardiovascular Diseases; Humans; Osteoprotegerin; Prognosis; Renal Insufficiency, Chronic; Risk Factors

Patients with chronic kidney disease (CKD) are at increased risk of osteoporosis and vascular calcification. Bone demineralization and vascular mineralization go often hand in hand in CKD, similar to as in the general population. This contradictory association is independent of aging and is commonly referred to as the "calcification paradox" or the bone-vascular axis. Various common risk factors and mechanisms have been identified. Alternatively, calcifying vessels may release circulating factors that affect bone metabolism, while bone disease may infer conditions that favor vascular calcification. The present review focuses on emerging concepts and major mechanisms involved in the bone-vascular axis in the setting of CKD. A better understanding of these concepts and mechanisms may identify therapeutics able to target and exert beneficial effects on bone and vasculature simultaneously.

Topics: Adaptor Proteins, Signal Transducing; Animals; Cardiovascular Diseases; Glucuronidase; Humans; Inflammation; Klotho Proteins; Osteoporosis; Osteoprotegerin; Parathyroid Hormone; Renal Insufficiency, Chronic; Signal Transduction; Vascular Calcification; Vitamin K

Vascular calcification (VC) is highly prevalent in patients with chronic kidney disease (CKD) and is strongly associated with cardiovascular mortality and morbidity. Accumulating evidence over the past decade has challenged the hypothesis of close interaction between bone and VC what raises the possibility of a common underlying pathophysiological mechanism. Lately, bone regulatory proteins such as: osteoprotegerin (OPG) and Receptor Activator for Nuclear Factor κB Ligand (RANKL) has attracted attention of researchers as a possible key mediators of bone-vascular calcification imbalance. The literature search was carried out using the MEDLINE/PubMed database and a combination of keywords and MeSH terms, and only papers published since January 2005 to July 2016 were selected. The search resulted in 562 potential articles. After selection according to the eligibility criteria, 107 studies fulfilled were included (102 full texts and 5 was case reports). OPG and RANKL plays essential role in the regulation of bone metabolism and may be regarded as a possible link between VC, bone and mineral metabolism in CKD patients. Further studies are required to determine the diagnostic significance of these proteins in evaluation of progression and severity of VC process in CKD patients. Finally, the efficacy and safety, especially in regard to VC, of anti-RANKL therapy in CKD patients requires well-designed prospective, randomized trials.

Topics: Animals; Bone Diseases; Humans; Osteoprotegerin; RANK Ligand; Renal Insufficiency, Chronic; Vascular Diseases

The link between vascular calcification (VC) and increased mortality is now well established. Over time, as clinical importance of this phenomenon has begun to be fully considered, scientists have highlighted more and more physiopathological mechanisms and signaling pathways that underlie VC. Several conditions such as diabetes, dyslipidemia and renal diseases are undoubtedly identified as predisposing factors. But even if the process is better understood, many questions still remain unanswered. This review briefly develops the various theories that attempt to explain mineralization genesis. Nonetheless, the main purpose of the article is to provide a profile of the various existing biomarkers of VC. Indeed, in the past years, a lot of inhibitors and promoters, which form a dense and interconnected network, were identified. Given importance to assess and control mineralization process, a focusing on accumulated knowledge of each marker seemed to be necessary. Therefore, we tried to define their respective role in the physiopathology and how they can contribute to calcification risk assessment. Among these, Klotho/fibroblast growth factor-23, fetuin-A, Matrix Gla protein, Bone morphogenetic protein-2, osteoprotegerin, osteopontin, osteonectin, osteocalcin, pyrophosphate and sclerostin are specifically discussed.

Topics: alpha-2-HS-Glycoprotein; Biomarkers; Bone Morphogenetic Protein 2; Calcium-Binding Proteins; Diabetes Complications; Diabetes Mellitus; Dyslipidemias; Extracellular Matrix Proteins; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Gene Expression Regulation; Humans; Matrix Gla Protein; Osteoprotegerin; Renal Insufficiency, Chronic; Risk Assessment; Signal Transduction; Vascular Calcification

Osteoprotegerin (OPG), sclerostin and DKK1 constitute opposite bone turnover inhibitors, OPG inhibiting osteoclastogenesis while sclerostin and DKK1 exerting their inhibitory effects on osteoblastogenesis. Both proteins have been recognized as strong risk factors of vascular calcifications in non-dialysis chronic kidney disease (ND-CKD) patients. The aim of this study was to investigate the relationships between these inhibitors and coronary artery calcifications (CAC) in this population.. A total of 241 ND-CKD patients [143 males; 69.0 (25.0-95.0) years; median estimated glomerular filtration rate using CKD-EPI 35.1 (6.7-120.1) mL/min/1.73 m(2)] were enrolled in this cross-sectional study. All underwent chest multidetector computed tomography for CAC scoring. OPG, sclerostin, DKK1 and mineral metabolism markers including PTH and bone alkaline phosphatase were measured. Logistic regression analyses were used to study the relationships between CAC and these markers.. Decline in renal function was associated with a significant increase in OPG and sclerostin while a slight but significant decrease in DKK1 was observed. The main crude associations with presence of CAC were a high level of OPG [OR = 2.55 95% confidence interval (95% CI) (1.35-4.82) for a level ranging from 6.26 to 9.15 pmol/L and OR = 5.74 95% CI (2.87-11.5) for a level ≥9.15 pmol/L; P < 0.0001] and a high level of sclerostin [OR = 2.64 95% CI (1.39-5.00) for a level ranging from 0.748 to 1.139 ng/mL and OR = 3.78 95% CI (1.96-7.31) for a level ≥1.139 ng/mL; P = 0.0002]. A logistic regression model clearly showed that the risk to present CAC was significantly increased when both OPG (≥6.26 pmol/L) and sclerostin (≥0.748 ng/mL) levels were high [crude model: OR = 11.47 95% CI (4.54-29.0); P < 0.0001; model adjusted for age, gender, diabetes, body mass index and smoking habits: OR = 5.69 95% CI (1.76-18.4); P = 0.02]. No association between DKK1 and presence of CAC was observed.. Our results strongly suggest that bone turnover inhibitors, OPG and sclerostin, are independently associated with CAC with potential additive effects in ND-CKD patients.

Topics: Adaptor Proteins, Signal Transducing; Adult; Aged; Aged, 80 and over; Biomarkers; Bone Morphogenetic Proteins; Bone Remodeling; Coronary Artery Disease; Cross-Sectional Studies; Female; Genetic Markers; Glomerular Filtration Rate; Humans; Male; Middle Aged; Osteoprotegerin; Renal Dialysis; Renal Insufficiency, Chronic; Risk Factors; Vascular Calcification

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a cytokine belonging to the TNF superfamily. TRAIL may modulate cell survival and proliferation through interaction with two different receptors, TRAIL-R1 and TRAIL-R2. The actions of TRAIL are regulated by three decoy receptors, TRAIL-R3, TRAIL-R4 and osteoprotegerin (OPG). There is evidence that both TRAIL and OPG are expressed by renal cells. The OPG/TRAIL axis has been recently linked to the pathogenesis of renal damage and, in particular, diabetic nephropathy.. In patients with kidney diseases, serum TRAIL and OPG levels are increased in parallel and are significantly associated with each other. In diabetic nephropathy, the renal expression of TRAIL and OPG is elevated, and in tubular cells proinflammatory cytokines enhance TRAIL expression. Additionally, a high-glucose microenvironment sensitizes tubular cells to apoptosis induced by TRAIL, whereas OPG counteracts the actions of TRAIL in cultured cells.. It seems that the expression and levels of TRAIL and OPG at serum and kidney levels are crucial for the pathogenesis of kidney diseases, and in particular diabetic nephropathy. Although further studies are necessary to clarify the exact role of the OPG/TRAIL axis in the kidney, this system seems to hold promise to provide therapeutic approaches for the management of renal damage.. See the Video Supplementary Digital Content 1 (http://links.lww.com/CONH/A5).

Topics: Animals; Apoptosis; Diabetic Nephropathies; Humans; Kidney; Osteoprotegerin; Renal Insufficiency, Chronic; Signal Transduction; TNF-Related Apoptosis-Inducing Ligand

Kidney transplantation is the treatment of choice for chronic kidney disease (CKD), but in kidney transplant recipients (KTRs) cardiovascular events are the first cause of death with a functioning graft, ranging from 36 to 55%. The impact of vascular calcification (VC) on morbidity and mortality of KTRs is not appreciated enough nowadays.. This review summarizes 13 important studies on VC in KTRs, comparing the results with CKD and dialysis populations. We focused on VC evaluation and use of coronary artery calcification (CAC) and aorta calcification (AoC) scores. We also evaluated the influence of traditional and non-traditional progression risk factors.. VC strongly predicts cardiovascular events and all-cause mortality in KTRs. VC assessment is important in KTRs and based essentially on multislice computed tomography or electron beam computed tomography recognition of lesions. Quantitative measurement of CAC and AoC scores is essential for a correct definition of the calcium burden before and after kidney transplant. Progression of CAC slows down but does not halt after kidney transplant. A variable association of both traditional and non-traditional risk factors is shown. There is a strong association between baseline CAC score and CAC progression. A significant improvement in secondary hyperparathyroidism after transplantation favorably affects the progression of CAC. Low 25(OH)D3 levels are an independent determinant of CAC progression. Diabetes is a risk factor for the presence of CAC in KTRs, but has not been independently associated with CAC progression. The data published on the use of immunosuppressive drugs as progression factors are few and inconclusive.

Topics: alpha-2-HS-Glycoprotein; Aorta; Calcifediol; Calcium-Binding Proteins; Cardiovascular Diseases; Coronary Vessels; Diabetes Mellitus; Disease Progression; Extracellular Matrix Proteins; Humans; Hyperparathyroidism, Secondary; Immunosuppressive Agents; Kidney Transplantation; Matrix Gla Protein; Osteoprotegerin; Renal Dialysis; Renal Insufficiency, Chronic; Risk Factors; Vascular Calcification

Vascular calcification is highly associated with cardiovascular disease mortality, particularly in high-risk patients with diabetes and chronic kidney diseases (CKD). In blood vessels, intimal calcification is associated with atherosclerosis, whereas medial calcification is a nonocclusive process which leads to increased vascular stiffness and reduced vascular compliance. In the valves, calcification of the leaflets can change the mechanical properties of the tissue and result in stenosis. For many decades, vascular calcification has been noted as a consequence of aging. Studies now confirm that vascular calcification is an actively regulated process and shares many features with bone development and metabolism. This review provides an update on the mechanisms of vascular calcification including the emerging roles of the RANK/RANKL/OPG triad, osteoclasts, and microRNAs. Potential treatments adapted from osteoporosis and CKD treatments that are under investigation for preventing and/or regressing vascular calcification are also reviewed.

Topics: Animals; Antibodies, Monoclonal, Humanized; Atherosclerosis; Calcinosis; Calcium; Chelating Agents; Denosumab; Diphosphonates; Humans; Mice; MicroRNAs; Osteoclasts; Osteoporosis; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Renal Insufficiency, Chronic; Teriparatide; Tunica Intima; Tunica Media; Vascular Calcification; Vascular Diseases

Chronic renal failure patients on dialysis are at a high risk of death due to vascular calcification. This study aimed at investigating the effect of omega-3 fatty acids on the vascular calcification biomarkers fetuin-A and osteoprotegerin (OPG) in patients with chronic renal failure who are undergoing hemodialysis. This prospective, open-label, controlled, parallel study included 60 hemodialysis patients who were randomized to receive either omega-3 fatty acids capsule along with their standard care of treatment (omega-3 group) or their standard care of treatment only (control group). Serum levels of fetuin-A, OPG, calcium, phosphorus, hemoglobin, parathyroid hormone, blood urea nitrogen (BUN), albumin, serum creatinine (SCr), and serum triglycerides (TG) were measured at baseline and after six months of intervention and follow-up of both groups. Significantly increased levels of fetuin-A and OPG (p < 0.001) were observed in the omega-3 group six months after the intervention compared with the control group. Levels of TG, albumin, SCr, BUN, phosphorous, calcium, hemoglobin, and parathyroid hormone were not significantly different in the omega-3 group compared with the control group after six months of intervention. Our study concluded that omega-3 may have a clinically beneficial effect in decreasing cardiovascular events by increasing the levels of the protective vascular calcification inhibitors fetuin-A and osteoprotegerin in chronic renal failure patients who are undergoing hemodialysis.

Topics: Albumins; alpha-2-HS-Glycoprotein; Biomarkers; Calcium; Fatty Acids, Omega-3; Female; Humans; Kidney Failure, Chronic; Osteoprotegerin; Parathyroid Hormone; Prospective Studies; Renal Dialysis; Renal Insufficiency, Chronic; Vascular Calcification

Cardiovascular disease (CVD) is the leading cause of death in patients with chronic kidney disease (CKD). Osteoprotegerin (OPG), known to regulate bone mass by inhibiting osteoclast differentiation and activation, might also play a role in vascular calcification. Increased circulating OPG levels in patients with CKD are associated with aortic calcification and increased mortality. We assessed the predictive role of OPG for all-cause and cardiovascular mortality in patients with CKD stages 3-5 over a 5-year follow-up period. We evaluated the relationship between OPG and all-cause and cardiovascular mortality in 145 CKD patients (stages 3-5) in a prospective observational follow-up study. Inflammation markers, including high-sensitivity C-reactive protein, standard echocardiography, and estimation of intima-media thickness in the common carotid artery, were assessed at baseline, and correlations with OPG levels were determined. The cutoff values for OPG were defined using ROC curves for cardiovascular mortality. Survival was assessed during follow up lasting for up to 5.5 years using Fine and Gray model. A total of 145 (89 men; age 58.9 ± 15.0 years) were followed up. The cutoff value for OPG determined using ROC was 10 pmol/L for general causes mortality and 10.08 pmol/L for CV causes mortality. Patients with higher serum OPG levels presented with higher mortality rates compared to patients with lower levels. Aalen-Johansen cumulative incidence curve analysis demonstrated significantly worse survival rates in individuals with higher baseline OPG levels for all-cause and cardiovascular mortality (p < 0.001). In multivariate analysis, OPG was a marker of general and cardiovascular mortality independent of sex, age, CVD, diabetes, and CRP levels. When CKD stages were included in the multivariate analysis, OPG was an independent marker of all-cause mortality but not cardiovascular mortality. Elevated serum OPG levels were associated with higher all-cause and cardiovascular mortality risk, independent of age, CVD, diabetes, and inflammatory markers, in patients with CKD.

Topics: Aged; Biomarkers; Cardiovascular Diseases; Female; Follow-Up Studies; Humans; Male; Middle Aged; Osteoprotegerin; Prospective Studies; Renal Insufficiency, Chronic

Vitamin D deficiency is common in peritoneal dialysis (PD) patients, so its supplementation has been advocated as potentially beneficial.. Double-blind, placebo-controlled, randomized clinical trial. Subjects on PD treated with high calcium peritoneal dialysate (Ca 3.5 mEq/l) and serum levels of 25-hydroxi vitamin D (25D) < 20 ng/ml were randomized to receive cholecalciferol (4800 IU/daily) or placebo for 16 weeks. The outcome measures were the effects on the osteogenic biomarkers osteoprotegerin (primary endpoint), intact fibroblast growth factor-23 (iFGF23), osteocalcin, osteopontin, iPTH, 1,25-dyhydroxivitamin D (1,25D), and interleukin-6.. Fifty-eight subjects were randomly assigned. Baseline characteristics were similar in both groups. Cholecalciferol supplemented subjects had a significant increase in serum 25D (from 11.4 ± 5.0 to 28.3 ± 10.3 ng/ml), 1,25D and iFGF23 compared with placebo group. iFGF23 levels increased an average of 10,875 pg/ml per month (95% CI 11,778-88,414) in the cholecalciferol group and was unchanged in the placebo group (2829 pg/ml, 95% CI - 2181 to 14,972). Extremely high iFGF23 levels (> 30,000 pg/ml) were observed in 74% of subjects receiving cholecalciferol although iFGF23 returned to baseline values after 32 weeks of withdrawal. The observed changes in iFGF23 correlated with 1,25D levels and were not modified by other variables. No difference was observed between groups in osteoprotegerin or other osteogenic biomarkers levels.. Cholecalciferol supplementation increases serum 25D levels in subjects on PD exposed to high calcium dialysate, yet it induces an exponential increase of iFGF23 in most patients, which disappear after withdrawal of supplementation and may be a major concern for this maneuver.

Topics: Adult; Aged; Biomarkers; Carotid Intima-Media Thickness; Cholecalciferol; Dietary Supplements; Double-Blind Method; Female; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Humans; Interleukin-6; Male; Middle Aged; Osteocalcin; Osteopontin; Osteoprotegerin; Parathyroid Hormone; Peritoneal Dialysis; Prospective Studies; Renal Insufficiency, Chronic; Vitamin D; Vitamin D Deficiency; Vitamins

Chronic kidney disease-mineral and bone disorder is a common complication in hemodialysis patients. The present study was designed to investigate the effects of flaxseed oil, a rich source of plant omega-3 fatty acid alpha-linolenic acid, on serum markers of bone formation and resorption in hemodialysis patients.. In this randomized controlled trial, 34 hemodialysis patients were randomly assigned to either the flaxseed oil or the control group. The patients in the flaxseed oil group received 6 g/d of flaxseed oil for 8 weeks, whereas the control group received 6 g/d of medium chain triglycerides oil. At baseline and the end of the 8th week, 7 mL of blood was obtained from each patient after a 12- to 14-hour fast and serum concentrations of osteocalcin, osteoprotegerin, N-telopeptide, and receptor activator of nuclear factor kappa B ligand were measured.. Serum N-telopeptide concentration decreased significantly up to 17% in the flaxseed oil group at the end of week 8, as compared to baseline (P < .01), and the reduction was significant in comparison with the control group. There were no significant differences between the two groups in the mean changes of serum osteocalcin, osteoprotegerin, or receptor activator of nuclear factor kappa B ligand.. This study indicates that daily consumption of 6 g/d of flaxseed oil may reduce bone resorption in hemodialysis patients.

Topics: Aged; Biomarkers; Bone Remodeling; Bone Resorption; Chronic Kidney Disease-Mineral and Bone Disorder; Collagen Type I; Dietary Supplements; Double-Blind Method; Female; Humans; Iran; Linseed Oil; Male; Middle Aged; Osteocalcin; Osteoprotegerin; Peptides; RANK Ligand; Renal Dialysis; Renal Insufficiency, Chronic; Time Factors; Treatment Outcome

Data on the predictive role of estimated glomerular filtration rate (eGFR) and osteoprotegerin (OPG) for cardiovascular (CVD) and all-cause mortality risk have been presented by our group and others. We now present data on the interactions between OPG with stage I to III chronic kidney disease (CKD) for all-cause and CVD mortality.. The setting was a 15-year study of 1,292 women over 70 years of age initially randomized to a 5-year controlled trial of 1.2 g of calcium daily. Serum OPG and creatinine levels with complete mortality records obtained from the Western Australian Data Linkage System were available. Interactions were detected between OPG levels and eGFR for both CVD and all-cause mortality (P < 0.05). Compared to participants with eGFR ≥60 ml/min/1.73 m2 and low OPG, participants with eGFR of <60 ml/min/1.73 m2 and elevated OPG had a 61% and 75% increased risk of all-cause and CVD mortality respectively (multivariate-adjusted HR, 1.61; 95% CI, 1.27-2.05; P < 0.001 and HR, 1.75; 95% CI, 1.22-2.55; P = 0.003). This relationship with mortality was independent of decline in renal function (P<0.05). Specific causes of death in individuals with elevated OPG and stage III CKD highlighted an excess of coronary heart disease, renal failure and chronic obstructive pulmonary disease deaths (P < 0.05).. The association between elevated OPG levels with CVD and all-cause mortality was more evident in elderly women with poorer renal function. Assessment of OPG in the context of renal function may be important in studies investigating its relationship with all-cause and CVD mortality.

Topics: Aged; Australia; Biomarkers; Cardiovascular Diseases; Cardiovascular System; Creatinine; Female; Glomerular Filtration Rate; Humans; Osteoprotegerin; Prospective Studies; Renal Insufficiency; Renal Insufficiency, Chronic; Risk Factors

Osteoprotegerin (OPG) is a molecule which belongs to the tumor necrosis factor receptor superfamily. OPG concentration is elevated in patients with left ventricle hypertrophy, heart failure and acute myocardial infarction. OPG concentrations rise in chronic kidney disease (CKD). The aim of this study was to investigate the association between OPG concentrations and cardiovascular complications, such as left ventricle hypertrophy, systolic and diastolic dysfunction of left ventricle and dysfunction of right ventricle in chronic kidney disease patients not treated with dialysis. The relation between OPG and the amount of pericardial fluid was also examined.. One hundred and one men with CKD stage 3-5 not treated with dialysis were included in the study. Overhydration, body fat mass and lean body mass were measured using bioimpedance spectroscopy (BIS). Echocardiography was performed to evaluate the amount of pericardial fluid and to measure the thickness of the interventricular septum (IVS), systolic and diastolic function of left ventricle, as well as systolic function of right ventricle.. We observed a significant positive association between OPG and the thickness of the interventricular septum, the size of the left atrium (LA) and the presence of pericardial fluid. A negative relationship was observed between OPG and ejection fraction (EF).. Our results suggest that OPG can be an independent marker of left ventricular hypertrophy, systolic and diastolic dysfunction of left ventricle and the presence of pericardial fluid in chronic kidney disease patients.

Topics: Heart Failure; Heart Ventricles; Humans; Hypertrophy, Left Ventricular; Male; Osteoprotegerin; Pericardial Fluid; Renal Dialysis; Renal Insufficiency, Chronic; Ventricular Dysfunction, Left

To clarify the mechanisms of the effect of osteoprotegerin (OPG) and sclerostin on vascular calcification and the state of the cardiovascular system in chronic kidney disease (CKD).. A total of 110 patients aged 18 to 65 years with CKD stages 35D were examined. OPG, sclerostin, intact parathyroid hormone, and serum troponin I were determined using the commercial "Enzyme-linked Immunosorbent Assay Kit for Sclerostin" from Cloude-Clone Corp. (USA) by enzyme-linked immunosorbent assay.. An increase in sclerostin and OPG levels was revealed, which significantly correlated with a decrease in glomerular filtration rate, as well as an increase in left ventricle myocardial mass index and peak systolic blood flow in the aortic arch.. Changes in the regulation of bone-mineral metabolism, in which the proteins inhibitors of bone metabolism, OPG and sclerostin, as well as the interactive interaction between the vascular and skeletal systems, play a decisive role in the development of lesions of the cardiovascular system caused by vascular calcification in CKD.. Цель. Уточнить механизмы влияния остеопротегерина (ОПГ) и склеростина на процессы кальцификации сосудов и состояние сердечно- сосудистой системы при хронической болезни почек (ХБП). Материалы и методы. Обследованы 110 пациентов в возрасте от 18 до 65 лет, страдающих ХБП С3С5Д. ОПГ, склеростин, интактный паратгормон, тропонин I в сыворотке крови определяли с использованием коммерческих наборов Enzyme-linked Immunosorbent Assay Kit for Sclerostin (Cloude-Clone Corp., США) методом иммуноферментного анализа. Результаты. Установлено повышение содержания склеростина и ОПГ, статистически значимо коррелирующее со снижением скорости клубочковой фильтрации, а также с увеличением индекса массы миокарда левого желудочка и пиковой систолической скоростью кровотока в дуге аорты. Заключение. Изменения в регуляции костно-минерального обмена, в котором участвуют белки-ингибиторы костного метаболизма ОПГ и склеростин, а также интерактивное взаимодействие между сосудистой и скелетной системами играют решающую роль в развитии поражений сердечно-сосудистой системы, обусловленных сосудистой кальцификацией при ХБП.

Topics: Bone Morphogenetic Proteins; Genetic Markers; Humans; Osteoprotegerin; Parathyroid Hormone; Renal Insufficiency, Chronic; Troponin I; Vascular Calcification

We aimed to investigate the factors affecting the development of atherosclerosis and the role of calcification inhibitors fetuin-A, matrix-Gla protein (MGP), osteoprotegerin (OPG) in atherosclerosis progress.. The study was planned to investigate the relationship of serum OPG, MGP and fetuin-A levels with the development of atherosclerosis in the stage 2-3-4-5 chronic kidney disease (CKD) patients who did not require dialysis treatment.. 32 (17 female, 15 male) healthy individuals and 92 (49 females, 43 males) CKD patients were included. The mean carotid intima-media thickness (CIMT), C-reactive protein (CRP), fetuin-A, OPG and MGP of the two groups were compared statistically. In CKD patients, age, body mass index (BMI), CRP, triglyceride, urea, systolic blood pressure (SBP), fasting blood sugar have a positive linear relationship, fetuin-A, OPG, GFR have a negative linear relationship with CIMT. The mean CIMT, right CIMT, left CIMT, blood urea, CRP, urinary albumin excretion creatinine and age show a negative linear relationship with fetuin-A.. Fetuin-A levels begin to decline from the early stages of CKD and are significantly lower in patients with atherosclerosis as expressed with CIMT. This suggests that fetuin-A may be used as an early marker in CKD for increased cardiovascular risk. Early recognition of these risk factors is important and large-scale studies on vascular calcification inhibitors are needed.

Topics: Adult; alpha-2-HS-Glycoprotein; Atherosclerosis; Biomarkers; C-Reactive Protein; Calcinosis; Carotid Intima-Media Thickness; Female; Humans; Linear Models; Male; Middle Aged; Osteoprotegerin; Renal Insufficiency, Chronic

Osteoprotegerin (OPG) belongs to the tumour necrosis factor superfamily and is known to accelerate endothelial dysfunction and vascular calcification. OPG concentrations are elevated in patients with chronic kidney disease. The aim of this study was to investigate the association between OPG levels and frequent complications of chronic kidney disease (CKD) such as anaemia, protein energy wasting (PEW), inflammation, overhydration, hyperglycaemia and hypertension.. One hundred non-dialysis-dependent men with CKD stage 3-5 were included in the study. Bioimpedance spectroscopy (BIS) was used to measure overhydration, fat amount and lean body mass. We also measured the serum concentrations of haemoglobin, albumin, total cholesterol, C-reactive protein (CRP), fibrinogen and glycated haemoglobin (HgbA1c), as well as blood pressure.. We observed a significant, positive correlation between OPG and age, serum creatinine, CRP, fibrinogen, HgbA1c concentrations, systolic blood pressure and overhydration. Negative correlations were observed between OPG and glomerular filtration rate (eGFR), serum albumin concentrations and serum haemoglobin level. Logistic regression models revealed that OPG is an independent marker of metabolic complications such as anaemia, PEW, inflammation and poor renal prognosis (including overhydration, uncontrolled diabetes and hypertension) in the studied population.. Our results suggest that OPG can be an independent marker of PEW, inflammation and vascular metabolic disturbances in patients with chronic kidney disease.

Topics: Aged; Anemia; Biomarkers; Humans; Inflammation; Logistic Models; Male; Middle Aged; Osteoprotegerin; Prognosis; Renal Dialysis; Renal Insufficiency, Chronic

The progression of chronic kidney disease (CKD) in children is associated with deregulated parathyroid hormone (PTH), growth retardation, and low bone accrual. PTH can cause both catabolic and anabolic impact on bone, and the activating transcription factor 4 (ATF4), a downstream target gene of PTH, is related to its anabolic effect. Osteoprotegerin (OPG) and receptor activator of NF-κB ligand (RANKL) are PTH-dependent cytokines, which may play an important role in the regulation of bone remodeling. This study aimed to evaluate the impact of endogenous PTH and the bone RANKL/OPG system on bone growth, cross-sectional geometry and strength utilizing young, nephrectomized rats. The parameters of cross-sectional geometry were significantly elevated in rats with CKD during the three-month experimental period compared with the controls, and they were strongly associated with serum PTH levels and the expression of parathyroid hormone 1 receptor (PTH1R)/ATF4 genes in bone. Low bone soluble RANKL (sRANKL) levels and sRANKL/OPG ratios were also positively correlated with cross-sectional bone geometry and femoral length. Moreover, the analyzed geometric parameters were strongly related to the biomechanical properties of femoral diaphysis. In summary, the mild increase in endogenous PTH, its anabolic PTH1R/ATF4 axis and PTH-dependent alterations in the bone RANKL/OPG system may be one of the possible mechanisms responsible for the favorable impact on bone growth, cross-sectional geometry and strength in young rats with experimental CKD.

Topics: Activating Transcription Factor 4; Animals; Biomechanical Phenomena; Bone and Bones; Bone Development; Femur; Gene Expression Regulation; Osteoprotegerin; Parathyroid Hormone; RANK Ligand; Rats; Receptors, Parathyroid Hormone; Renal Insufficiency, Chronic; Solubility

Background Sclerostin and osteoprotegerin (OPG) are new markers of chronic kidney disease (CKD) mediated mineral bone disease (CKD-MBD) which were extensively evaluated in adult population. We aimed to evaluate the associations between serum levels of sclerostin/OPG and parameters of bone turnover and compare the serum levels of sclerostin/OPG in different stages of CKD in children. Methods 70 children with CKD stage 1-5, aged 2-21 years were examined. Serum levels of alkaline phosphatase (ALP), creatinine, total calcium, phosphorus , intact parathyroid hormone (iPTH) and vitamin D were measured. Serum sclerostin and OPG levels were measured in children with different levels of CKD stage and their association with bone turnover parameters were noted. Results We did not observe any significant correlation between serum levels of sclerostin and OPG and stages of CKD. A negative relationship was present between serum sclerostin and 25-OH vitamin D levels. Osteoprotegerin was positively and significantly correlated with ALP but serum sclerostin was negatively correlated with ALP. Conclusion Our study, which includes only children and adolescents with a growing skeleton under uremic conditions and excluding diabetes and atherosclerosis interference, is very valuable. We couldn't find any significant relationship between either sclerostin or OPG levels among different stages of CKD. Also our study demonstared a strong negative relationship between ALP and sclerostin levels and a strong positive relationship between ALP and OPG levels, reminding the importance of ALP levels to predict the bone-mineral status of the children with CKD.

Topics: Adaptor Proteins, Signal Transducing; Adolescent; Adult; Age of Onset; Biomarkers; Bone Diseases; Child; Child, Preschool; Female; Glomerular Filtration Rate; Humans; Male; Minerals; Osteoprotegerin; Prognosis; Renal Insufficiency, Chronic; Turkey; Young Adult

Chronic kidney disease (CKD) is an irreversible loss of kidney function, and it represents a major global public health burden due to both its prevalence and its continuously increasing incidence. Mineral bone disorders (MBDs) constitute a hallmark of CKD, and alongside cardiovascular complications, they underlie a poor prognosis for these patients. Thus, our study focused on novel CKD biomarker patterns and their impact on the clinical staging of the disease. As a first testing approach, the relative expression levels of 105 proteins were assessed by the Proteome Profiler Cytokine Array Kit for pooled CKD stage 2-4 serum samples to establish an overall view regarding the proteins involved in CKD pathogenesis. Among the molecules that displayed significant dysregulation in the CKD stages, we further explored the involvement of Dickkopf-related protein 1 (Dkk-1), a recognised inhibitor of the Wnt signalling pathway, and its crosstalk with 1,25OH

Topics: Aged; Algorithms; Biomarkers; Bone Density; Bone Diseases; Calcitriol; Cross-Sectional Studies; Female; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Humans; Inflammation; Intercellular Signaling Peptides and Proteins; Interleukin-6; Male; Middle Aged; Osteocalcin; Osteopontin; Osteoprotegerin; Phenotype; Prognosis; Proteome; Renal Insufficiency, Chronic; Tumor Necrosis Factor-alpha; Wnt Signaling Pathway

Secondary hyperparathyroidism is a complication of chronic kidney disease that compromises skeletal integrity. In patients with secondary hyperparathyroidism undergoing parathyroidectomy, parathyroid hormone levels dramatically decrease. The effects of parathyroidectomy on bone tissue are poorly understood, especially regarding the proteins expressed by osteocytes, such as fibroblast growth factor 23, dentin matrix protein 1, matrix extracellular phosphoglycoprotein, sclerostin, receptor activator of nuclear factor kappa B ligand (RANKL) and osteoprotegerin, which regulate bone turnover. The objective of this study was to characterize the bone expression of these proteins by immunohistochemistry and correlate these results with those of bone histomorphometry before and after parathyroidectomy. We studied bone biopsies that were obtained from 23 patients before and 12 months after parathyroidectomy. We observed an improvement in bone microarchitecture, but impaired mineralization after parathyroidectomy. We found significant increases in sclerostin and osteoprotegerin expression and a decrease in the RANKL/osteoprotegerin ratio after parathyroidectomy, suggesting that their expression is regulated by parathormone. These proteins correlated with structural and bone formation parameters. We conclude that after parathyroidectomy, significant changes occur in the bone expression of osteocyte proteins and that these proteins potentially regulate bone remodeling.

Topics: Adaptor Proteins, Signal Transducing; Bone and Bones; Humans; Hyperparathyroidism, Secondary; Osteocytes; Osteoprotegerin; Parathyroidectomy; Renal Insufficiency, Chronic

High plasma osteoprotegerin (OPG) and asymmetric dimethylarginine (ADMA) and low homoarginine (hArg) predict adverse renal and cardiovascular (CV) outcomes. In patients with chronic kidney disease and stable coronary artery disease, plasma OPG correlated with hArg (r = - 0.37, P = 0.03) and the hArg/ADMA molar ratio (r = - 0.46, P = 0.009), which was maintained upon adjustment for renal function. Elevated OPG levels and decreased hArg/ADMA ratios independently predicted 4-year composite CV and renal endpoints (CV death or progression to dialysis). Thus, high OPG and low hArg/ADMA ratio, albeit interrelated, appear to independently contribute to adverse clinical outcome.

Topics: Aged; Arginine; Biomarkers; Coronary Artery Disease; Homoarginine; Humans; Male; Middle Aged; Osteoprotegerin; Renal Insufficiency, Chronic

To investigate the correlation between elevated serum sclerostin levels and chronic kidney disease outcomes for patients receiving peritoneal dialysis (PD).. We performed a prospective observational study in stable PD patients. Serum sclerostin levels were determined via enzyme immunoassay, and median levels of sclerostin were used to divide patients into high and low sclerostin groups. New-onset cardiovascular events (CVEs) and cardiovascular mortality were evaluated during a 6-year follow-up period.. Ninety-eight patients [mean age 52.5 ± 10.9 years, 49% males, 21.4% diabetic, median dialysis vintage 40.7 (range 17.9-72.2) months] were recruited. Compared with those in the low sclerostin group, patients in the high sclerostin group demonstrated higher levels of total-cholesterol, NT-proBNP, and osteoprotegerin (all P < 0.05). During the 6-year study period, 25 CVEs and 17 cardiovascular deaths occurred in the high sclerostin group, whereas 11 CVEs and four cardiovascular deaths occurred in the low sclerostin group. A Cox regression analysis determined that high sclerostin levels significantly increased the risk for CVEs (HR 2.475, 95% CI 1.116-5.489, P = 0.026) and cardiovascular death (HR 3.484, 95% CI1.134-10.706, P = 0.029), after multiple adjustments were made.. Our data suggest that high sclerostin levels may predict the onset of CVEs and cardiovascular mortality among PD patients.

Topics: Adaptor Proteins, Signal Transducing; Adult; Bone Morphogenetic Proteins; Cardiovascular Diseases; Cholesterol; Female; Follow-Up Studies; Genetic Markers; Humans; Male; Middle Aged; Natriuretic Peptide, Brain; Osteoprotegerin; Peptide Fragments; Peritoneal Dialysis; Prospective Studies; Renal Insufficiency, Chronic; Risk Factors

Vascular calcification (VC) and atherosclerosis are associated with an increased cardiovascular morbimortality in chronic kidney disease (CKD). Osteoprotegerin (OPG) and osteopontin (OPN) are involved in both VC and CKD. Soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) has been related to cardiovascular disease. We hypothesized that OPG, OPN and sTWEAK levels may be associated with a higher prevalence of cardiovascular outcomes in patients with CKD.. The presence of calcified or non-calcified atherosclerotic plaques was assessed in 1043 stage 3 to 5D CKD patients from The NEFRONA Study. Biochemical measurements and OPG, OPN and sTWEAK serum levels were analyzed. Patients were followed for cardiovascular outcomes (41 ± 16 months).. At recruitment, 26% of CKD patients had VC. The adjusted odds ratios for having VC were 2.22 (1.32-3.75); p=.003 for OPG, and 0.45 (0.24-0.84); p=.01 for sTWEAK concentrations. After follow-up, 95 CV events occurred. In a Cox model, patients with OPG or OPN above and sTWEAK below their optimal cut-off points had an adjusted higher risk of cardiovascular events [HR: 2.10 (1.49-3.90); p=.02; 1.65 (1.02-2.65); p=.04; 2.05 (1.28-3.29), p=.003; respectively]. When CKD patients were grouped according to the number of biomarkers above (OPG and OPN) or below (sTWEAK) their cut-off points, the combination of these biomarkers showed the highest risk for cardiovascular events [HR: 9.46 (3.80-23.5) p < .001]. A composite score of these three biomarkers increased the C-statistic and net reclassification index beyond conventional risk factors and VC.. The combination of OPG, OPN and sTWEAK increased the predictability of cardiovascular outcomes.

Topics: Aged; Biomarkers; Cardiovascular Diseases; Cytokine TWEAK; Female; Humans; Male; Middle Aged; Osteopontin; Osteoprotegerin; Predictive Value of Tests; Prevalence; Prognosis; Prospective Studies; Renal Insufficiency, Chronic; Risk Assessment; Risk Factors; Spain; Time Factors; Vascular Calcification

Osteoprotegerin (OPG), receptor activator of NF-κB ligand (RANKL), and parathyroid hormone (PTH) play a central role in the regulation of bone turnover in chronic kidney disease (CKD), but their influence on bone mineral density (BMD) and strength remains unclear, particularly in children. We studied the clinical significance of OPG and RANKL in relation to PTH, femur weight, BMD, and bone biomechanical properties in growing rats after one month (CKD-1) and three months (CKD-3) of surgically-induced mild CKD. Gene expression of parathyroid hormone 1 receptor (PTH1R) and activating transcription factor 4 (ATF4), major regulators of anabolic PTH response in bone, was also determined. Serum PTH and bone PTH1R/ATF4 expression was elevated in CKD-3 compared with other groups, and it positively correlated with femur weight, BMD, and the biomechanical properties of the femoral diaphysis reflecting cortical bone strength. In contrast, bone RANKL/OPG ratios were decreased in CKD-3 rats compared with other groups, and they were inversely correlated with PTH and the other abovementioned bone parameters. However, the PTH-PTH1R-ATF4 axis exerted an unfavorable effect on the biomechanical properties of the femoral neck. In conclusion, this study showed for the first time an inverse association between serum PTH and the bone RANKL/OPG system in growing rats with mild CKD. A decrease in the RANKL/OPG ratio, associated with PTH-dependent activation of the anabolic PTH1R/ATF4 pathway, seems to be responsible for the unexpected, beneficial effect of PTH on cortical bone accrual and strength. Simultaneously, impaired biomechanical properties of the femoral neck were observed, making this bone site more susceptible to fractures.

Topics: Activating Transcription Factor 4; Animals; Biomechanical Phenomena; Bone and Bones; Bone Density; Femur; Gene Expression Regulation; Male; Organ Size; Osteoprotegerin; Parathyroid Hormone; RANK Ligand; Rats, Wistar; Receptor, Parathyroid Hormone, Type 1; Renal Insufficiency, Chronic; Uremia; X-Ray Microtomography

We studied the correlations between circulating osteoprotegerin (OPG) level and radial artery calcification (RAC) assessed histologically and carotid artery intima-media thickness (CCA-IMT). Moreover, we studied the relationship between OPG levels and all-cause and cardiovascular (CV) mortality during a 5-year observation period. The study comprised 59 CKD patients (36 hemodialyzed (HD), 23 predialysis). The biochemical parameters included: creatinine, calcium, phosphate, intact parathormone, C-reactive protein, interleukin-6, tumor necrosis factor receptor II (TNFRII), transforming growth factor-β, hepatocyte growth factor, fibroblast growth factor 23, osteonectin (ON), osteopontin, osteoprotegerin, and osteocalcin. CCA-IMT and the presence of atherosclerotic plaques was assessed by ultrasound. Fragments of radial artery obtained during creation of HD access were prepared for microscopy and stained for calcifications with alizarin red. RAC was detected in 34 patients (58%). In multiple regression adjusted for dialysis status, TNFRII, ON and Framingham risk score (FRS) were identified as the independent predictors of OPG. Serum OPG above the median value of 7.55 pmol/L significantly predicted the presence of RAC in simple logistic regression (OR 5.33; 95%CI 1.39-20.4; P = 0.012) and in multiple logistic regression adjusted for FRS, dialysis status and CCA-IMT values (OR 6.56; 95%CI 1.06-40.6; P = 0.036). OPG levels above the median were associated with higher CCA-IMT values (1.02 ± 0.10 vs. 0.86 ± 0.13; P < 0.001) and predicted the presence of atherosclerotic plaques in carotid artery (OR 14.4; 95%CI 2.84-72.9; P < 0.001), independently of FRS, dialysis status and RAC. In this study, elevated serum OPG levels correlated with higher CCA-IMT, the presence of atherosclerotic plaques and the severity of the RAC independently of each other. During follow-up, 25 patients (42%) died, including 21 due to CV causes. In multiple Cox regression, OPG above the median predicted overall survival independently of dialysis status, Framingham risk score, CCA-IMT above the median value, and the presence of atherosclerotic plaques in CCA, but not independently of RAC. We postulate that circulating OPG may play a dual role as a marker for both medial arterial calcification and atherosclerosis, hence it seems to be a valuable tool for assessing CV risk in patients with CKD. OPG might be an early indicator of all-cause mortality in CKD patients with advanced medial arterial ca

Topics: Adult; Aged; Biomarkers; Cardiovascular Diseases; Carotid Intima-Media Thickness; Female; Follow-Up Studies; Humans; Logistic Models; Male; Middle Aged; Osteoprotegerin; Plaque, Atherosclerotic; Radial Artery; Renal Dialysis; Renal Insufficiency, Chronic; Severity of Illness Index; Survival Rate; Vascular Calcification

PiT-2, a type III sodium-dependent phosphate transporter, is a causative gene for the brain arteriolar calcification in people with familial basal ganglion calcification. Here we examined the effect of PiT-2 haploinsufficiency on vascular calcification in uremic mice using wild-type and global PiT-2 heterozygous knockout mice. PiT-2 haploinsufficiency enhanced the development of vascular calcification in mice with chronic kidney disease fed a high-phosphate diet. No differences were observed in the serum mineral biomarkers and kidney function between the wild-type and PiT-2 heterozygous knockout groups. Micro computed tomography analyses of femurs showed that haploinsufficiency of PiT-2 decreased trabecular bone mineral density in uremia. In vitro, sodium-dependent phosphate uptake was decreased in cultured vascular smooth muscle cells isolated from PiT-2 heterozygous knockout mice compared with those from wild-type mice. PiT-2 haploinsufficiency increased phosphate-induced calcification of cultured vascular smooth muscle cells compared to the wild-type. Furthermore, compared to wild-type vascular smooth muscle cells, PiT-2 deficient vascular smooth muscle cells had lower osteoprotegerin levels and increased matrix calcification, which was attenuated by osteoprotegerin supplementation. Thus, PiT-2 in vascular smooth muscle cells protects against phosphate-induced vascular calcification and may be a therapeutic target in the chronic kidney disease population.

Topics: Animals; Biomarkers; Bone Density; Female; Haploinsufficiency; Heterozygote; Mice; Mice, Knockout; Myocytes, Smooth Muscle; Osteoprotegerin; Phosphates; Renal Insufficiency, Chronic; Sodium-Phosphate Cotransporter Proteins, Type III; Uremia; Vascular Calcification

Osteoprotegerin (OPG) plays protective roles against the development of vascular calcification (VC) which greatly contributes to the increased cardiovascular events in patients with chronic kidney disease (CKD). The present study aimed to find the non-traditional, kidney-related cardiovascular risk factors correlated to serum OPG and the effect of serum OPG on the arterial stiffness measured by brachial ankle pulse wave velocity (baPWV) in patients with the pre-dialysis CKD.. We cross-sectionally analyzed the data from the patients in whom baPWV and the serum OPG were measured at the time of enrollment in a prospective pre-dialysis CKD cohort study in Korea.. Along with traditional cardiovascular risk factors such as age, diabetes mellitus, pulse pressure, and baPWV, non-traditional, kidney-related factors such as albuminuria, plasma level of hemoglobin, total CO. Non-traditional, kidney-related cardiovascular risk factors in addition to traditional cardiovascular risk factors were related to serum level of OPG in CKD. Serum OPG level was significantly related to baPWV. Our study suggests that kidney-related factors involved in CKD-specific pathways for VC play a role in the increased secretion of OPG into circulation in patients with CKD.. ClinicalTrials.gov Identifier: NCT01630486.

Topics: Adult; Aged; Blood Pressure; Cardiovascular Diseases; Creatinine; Cross-Sectional Studies; Diabetes Mellitus; Female; Humans; Linear Models; Male; Middle Aged; Osteoprotegerin; Pulse Wave Analysis; Renal Insufficiency, Chronic; Risk Factors; Vascular Stiffness

Chronic Kidney Disease (CKD)-Mineral and Bone Disorder (CKD-MBD) is a complex disease that is not completely understood. However, some factors secreted by the osteocytes might play an important role in its pathophysiology. Therefore, we evaluated the bone expression of proteins in a group of patients with CKD 2-3, CKD 4, and CKD 5 on dialysis and healthy individuals. We also tested several bone remodeling markers, and correlated these levels with bone biopsy findings. As expected, as serum calcium decreased, serum phosphate, alkaline phosphatase, fibroblast growth factor-23 (FGF-23), parathyroid hormone, and osteoprotegerin increased, as CKD progressed. Additionally, there was a gradual increase in bone resorption associated with a decrease in bone formation and impairment in bone mineralization. Bone expression of sclerostin and parathyroid hormone receptor-1 seemed to be increased in earlier stages of CKD, whereas FGF-23 and phosphorylated β-catenin had increased expression in the late stages of CKD, although all these proteins were elevated relative to healthy individuals. Immunohistochemical studies showed that FGF-23 and sclerostin did not co-localize, suggesting that distinct osteocytes produce these proteins. Moreover, there was a good correlation between serum levels and bone expression of FGF-23. Thus, our studies help define the complex mechanism of bone and mineral metabolism in patients with CKD. Linkage of serum markers to bone expression of specific proteins may facilitate our understanding and management of this disease.

Topics: Adaptor Proteins, Signal Transducing; Adult; Aged; beta Catenin; Biomarkers; Biopsy; Bone and Bones; Bone Morphogenetic Proteins; Bone Remodeling; Calcium; Case-Control Studies; Chronic Kidney Disease-Mineral and Bone Disorder; Female; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Genetic Markers; Humans; Male; Middle Aged; Osteocytes; Osteoprotegerin; Parathyroid Hormone; Phosphorylation; Receptor, Parathyroid Hormone, Type 1; Renal Dialysis; Renal Insufficiency, Chronic; Severity of Illness Index

Osteoprotegerin (OPG) is a glycoprotein that plays an important regulatory role in the skeletal, vascular, and immune system. It has been shown that OPG predicts chronic kidney disease (CKD) in diabetic patients. We hypothesized that OPG could be a risk marker of CKD development also in non-diabetic hypertensive patients.. A case-control study was carried out to measure circulating OPG levels in 42 hypertensive patients with CKD and in 141 hypertensive patients without CKD. A potential relationship between OPG and the presence of CKD was investigated and a receiver-operating characteristic (ROC) curve was designed thereafter to identify a cut-off value of OPG that best explained the presence of CKD. Secondly, to evaluate whether OPG increase could affect the kidney, 18 C57BL/6J mice were randomized to be treated with saline or recombinant OPG every 3 weeks for 12 weeks.. Circulating OPG levels were significantly higher in hypertensive patients with CKD, and there was a significant inverse association between OPG and renal function, that was independent from other variables. ROC analysis showed that OPG levels had a high statistically predictive value on CKD in hypertensive patients, which was greater than that of hypertension. The OPG best cut-off value associated with CKD was 1109.19 ng/L. In the experimental study, OPG delivery significantly increased the gene expression of pro-inflammatory and pro-fibrotic mediators, as well as the glomerular nitrosylation of proteins.. This study shows that OPG is associated with CKD in hypertensive patients, where it might have a higher predictive value than that of hypertension for CKD development. Secondly, we found that OPG delivery significantly increased the expression of molecular pathways involved in kidney damage. Further longitudinal studies are needed not only to evaluate whether OPG predicts CKD development but also to clarify whether OPG should be considered a risk factor for CKD.

Topics: Aged; Animals; Biomarkers; Case-Control Studies; Female; Follow-Up Studies; Humans; Hypertension; Male; Mice; Mice, Inbred C57BL; Middle Aged; Osteoprotegerin; Random Allocation; Renal Insufficiency, Chronic

The prevalence of chronic kidney disease (CKD) is rising continuously. Cardiovascular disease (CVD) is among the leading causes of death and premature mortality of patients with CKD. It has been suggested that the assessment of CKD-associated CVD risk factors together with conventional risk factors should be performed in order to improve the prediction of coronary heart disease risk. The reduction of these factors seems to be effective in lowering cardiovascular (CV) morbidity and mortality in patients with CKD. Measuring subclinical atherosclerosis in CKD may significantly improve CVD risk prediction. Additionally, novel early atherosclerosis biomarkers, as well as possible therapeutic targets, are greatly needed in CKD patients. Matrix Metalloproteinase 2 (MMP2) and osteoprotegerin (OPG) may fall into this category of both useful markers and targets in CKD disease. The aim of this study was to investigate MMP2 and OPG as markers of increased risk of atherosclerosis in CKD. The present study included 40 patients with CKD divided into two groups: 20 patients with stage 1-4 (group I) and 20 patients with end stage renal disease (ESRD) (group II). They were compared with 20 sex and age matched healthy individuals as a control group (group III). Levels of MMP2, OPG were measured by ELISA. Cardiac echocardiography was performed to assess structural integrity and function. There was highly significant increase in MMP2 and OPG levels in group II when compared with group I and group III (P=0.000 and P=0.000 respectively) and in group I when compared with group III (P=0.000). A highly significant difference was also found between the three groups as regard mitral and aortic calcification (P=0.000) and mitral, aortic and tricuspid regurge (P=0.000, 0.002 and 0.001 respectively). There was a positive correlation between OPG and MMP2 and significant relation between OPG and mitral and aortic calcification. In conclusion, MMP-2 and OPG may be involved in the pathogenesis of atherosclerosis in patients with CKD and could potentially be of use as biomarkers of subclinical atherosclerosis in these patients. The increase in mitral and aortic calcifications may suggest the reasons for increased CV risk in these patients.

Topics: Atherosclerosis; Biomarkers; Egypt; Humans; Matrix Metalloproteinase 2; Osteoprotegerin; Renal Insufficiency, Chronic; Risk Factors

Vascular calcification (VC) is closely related to cardiovascular events in chronic kidney disease (CKD). Apelin has emerged as a potent regulator of cardiovascular function, but its role in VC during CKD remains unknown. We determined whether apelin plays a role in phosphate-induced mineralization of human aortic smooth muscle cells (HASMCs) and in adenine-induced CKD rats with aortic calcification.. In vitro, apelin-13 was found to inhibit calcium deposition in HASMCs (Pi(+) Apelin(+) group vs Pi(+) Apelin(-) group: 50.1 ± 6.21 ug/mg vs 146.67 ± 10.02 ug/mg protein, p = 0.012) and to suppress the induction of the osteoblastic transformation genes BMP-2, osteoprotegerin (OPG) and Cbfa1. This effect was mediated by interference of the sodium-dependent phosphate cotransporter (Pit-1) expression and phosphate uptake. In vivo, decreased plasma apelin levels (adenine(+) apelin(-) vs vehicle: 0.37 ± 0.09 ng/ml vs 0.68 ± 0.16 ng/ml, p = 0.003) and downregulation of APJ in the aorta were found in adenine-induced CKD rats with hyperphosphatemia (adenine(+) apelin(-) vs vehicle: 6.91 ± 0.23 mmoL/L vs 2.3 ± 0.07 mmoL/L, p = 0.001) and aortic calcification. Exogenous supplementation of apelin-13 normalized the level of the apelin/APJ system and significantly ameliorated aortic calcification, as well as the suppression of Runx2, OPG and Pit-1 expression.. Apelin ameliorates VC by suppressing osteoblastic differentiation of VSMCs through downregulation of Pit-1. These results suggest apelin may have potential therapeutic value for treatment of VC in CKD.

Topics: Animals; Aorta, Thoracic; Blotting, Western; Cells, Cultured; Core Binding Factor Alpha 1 Subunit; Gene Expression Regulation; Immunohistochemistry; Intercellular Signaling Peptides and Proteins; Ligands; Male; Muscle, Smooth, Vascular; Osteoprotegerin; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Renal Insufficiency, Chronic; RNA; Sodium-Phosphate Cotransporter Proteins, Type III; Vascular Calcification

The prevalence of chronic kidney disease is rising continuously. Cardiovascular disease is among leading causes of death and premature mortality of patients with chronic kidney disease. Even the earliest stages of chronic kidney disease are associated with higher risk of subsequent coronary heart disease. The aim of this study was to determine markers of increased risk of atherosclerosis in CKD.. The study group consisted of a total of 80 patients (20 patients with stage I/II CKD, 20 with stage III CKD, 20 stage IV CKD and 20 stage V/dialysis) and 24 healthy volunteers. Levels of proteins (osteoprotegerin, osteopontin, osteocalcin, matrix γ-carboxyglutamic acid protein, fetuin A, MMP-2, MMP-9, TIMP-1, TIMP-2) and biochemical parameters were measured to analyse their influence on atherosclerosis risk in CKD patients. Cardiac echocardiography was performed to assess structural integrity and function, presence of left ventricular hypertrophy and systolic and diastolic function dysfunction.. This study shows that the prevalence of ventricular hypertrophy (95.3 %) and diastolic dysfunction (93.2 %) in CKD patients is high. Also E/E' ratio was significantly higher (13.6 ± 4.4, p = 0.001), tricuspid insufficiency (27.3 in CKD I/II vs. 71.4 in CKD V, p = 0.016), contractile dysfunction (33.3 in CKD I/II vs. 78.9 in CKD V, p = 0.040), mitral valve calcification (0 in CKD I/II vs. 28.6 in CKD V, p = 0.044) and aortic valve calcification (0 in CKD I/II vs. 61.9 in CKD V, p = 0.0008) were significantly more frequent in patients with CKD stage V/dialysis than in other groups. Only MMP-2, MMP-2/TIMP-2 ratio and TIMP-1 differed significantly between groups.. This study shows high prevalence of ventricular hypertrophy and diastolic dysfunction in CKD patients. Contractile dysfunction, mitral and aortic valve calcification in HD patients were significantly more frequent than in patients with other CKD stages. Significantly increased levels of MMP-2, MMP-2/TIMP-2 ratio and lower TIMP-1 suggests that these factors may be involved in the pathogenesis of atherosclerosis in CKD patients.

Topics: Aged; alpha-2-HS-Glycoprotein; Biomarkers; Calcium-Binding Proteins; Echocardiography; Extracellular Matrix Proteins; Female; Humans; Hypertrophy, Left Ventricular; Male; Matrix Gla Protein; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Middle Aged; Osteocalcin; Osteopontin; Osteoprotegerin; Renal Insufficiency, Chronic; Tissue Inhibitor of Metalloproteinase-1; Tissue Inhibitor of Metalloproteinase-2

To evaluate osteoprotegerin (OPG) levels in relation to cardiovascular (CV) risk factors in patients with chronic kidney disease (CKD) on different regimens of renal replacement therapy.. A total of 143 patients with CKD and 30 healthy controls were included in this study and divided into five categories, including predialysis patients with chronic renal failure (preD; n = 36), chronic peritoneal dialysis patients (PD; n = 36), hemodialysis patients (HD; n = 35), renal transplant patients (RT; n = 36), and controls (n = 30). Data on demographics, concomitant diseases and CV risk factors, serum OPG levels, and correlates of serum OPG levels were determined.. Serum OPG (pmol/l) levels were significantly higher in HD (P <0.001 for each), PD (P <0.001 for each), and preD (P <0.01 vs. control, P <0.05 vs. RT) groups than RT and control groups. Diabetics than nondiabetics in HD (P = 0.008), PD (P = 0.024), and RT (P = 0.004) groups and males than females in PD group (P = 0.021) had higher OPG levels. Serum OPG levels were associated positively with age in HD (P <0.001), PD (P = 0.001), and in overall population (P <0.001).. Our findings revealed increased serum levels of OPG in dialysis and preD patients compared to RT and controls. In the patient groups receiving two dialysis treatment, the levels were worse, indicating a more pronounced vascular injury. Age, C-reactive protein (CRP), high-density lipoprotein cholesterol (HDL-C), and cystatin C (CysC) in CKD patients, CRP and PTH in the control subjects, and age and BMI in the overall population were the significant correlates of serum OPG levels.

Topics: Adult; Aged; Body Mass Index; C-Reactive Protein; Cardiovascular Diseases; Cystatin C; Enzyme-Linked Immunosorbent Assay; Female; Humans; Lipoproteins, HDL; Male; Middle Aged; Osteoprotegerin; Renal Dialysis; Renal Insufficiency, Chronic; Risk Factors

Vascular injury and dysfunction contribute to cardiovascular disease, the leading cause of death in patients with chronic kidney disease (CKD). Osteoprotegerin (OPG) is a soluble member of the tumor necrosis factor receptor superfamily that has been linked to atherogenesis and endothelial dysfunction. Elevated circulating OPG levels predict future cardiovascular events (CVE). Our aim was to evaluate the determinants of circulating OPG levels, to investigate the relationship between OPG and markers of vascular damage and to test whether OPG improves risk stratification for future CVE beyond traditional and renal-specific risk factors in a CKD population. 291 patients with CKD stage 1-5 not on dialysis were included in the study. In the multivariate analysis, OPG was a significant predictor for flow-mediated dilatation, but not for carotid intima media thickness levels. During follow-up (median 36 months, IQR = 32-42 months), 87 patients had CVE. In the Cox survival analysis, OPG levels were independently associated with CVE even after adjustment for traditional and renal-specific cardiovascular risk factors. The addition of OPG to a model based on commonly used cardiovascular factors significantly improved the reclassification abilities of the model for predicting CVE. We show for the first time that OPG improves risk stratification for CVE in a non-dialysis CKD population, above and beyond a model with established traditional and renal-specific cardiovascular risk factors, including estimated glomerular filtration rate and fibroblast growth factor 23.

Topics: Adult; Aged; Atherosclerosis; Cardiovascular Diseases; Carotid Intima-Media Thickness; Female; Glomerular Filtration Rate; Humans; Inflammation; Male; Middle Aged; Osteoprotegerin; Renal Insufficiency, Chronic; Risk Factors

Numerous biomarkers have been shown to associate with clinical endpoints in chronic kidney disease (CKD). There is limited evidence whether biomarkers improve risk prediction in relation to clinical outcomes. Our study investigates whether a small suite of key chronic kidney disease-mineral and bone disorder biomarkers could be used to enhance risk assessment in CKD.. Fetuin-A, fibroblast growth factor-23 and osteoprotegerin were measured on baseline plasma samples from 463 patients recruited to the Chronic Renal Insufficiency Standards Implementation Study. The biomarkers were analysed in relation to progression to end stage kidney disease, death and major cardiovascular events.. Over a median follow up of 46 months (interquartile range 21-69), fibroblast growth factor-23 was associated with risk for renal replacement therapy (hazard ratio (HR) 1.35, P = 0.05, 95% confidence interval (CI) 1.001-1.820), cardiovascular events (HR 1.74 P < 0.001, 95% CI 1.303-1.305) and death (HR 1.4 P = 0.005, 95% CI 1.109-1.767). Osteoprotegerin was associated with risk for death (HR 1.06, P = 0.03, 95% CI 1.006-1.117). There was no clear association between Fetuin-A and any of the clinical endpoints. The addition of biomarkers to risk models led to marginal improvement in model discrimination and reclassification.. Biomarkers are often associated with clinical endpoints, and we observed such associations in our study of patients with advanced CKD. However, the markers analysed in our study were of limited benefit in improving the prediction of these outcomes. Any extra information biomarkers may provide to improve risk prediction in clinical practice needs to be carefully balanced against the potential cost of these tools.

Topics: Aged; alpha-2-HS-Glycoprotein; Area Under Curve; Biomarkers; Cardiovascular Diseases; Disease Progression; Female; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Humans; Kidney Failure, Chronic; Male; Middle Aged; Multivariate Analysis; Odds Ratio; Osteoprotegerin; Predictive Value of Tests; Prognosis; Proportional Hazards Models; Prospective Studies; Renal Dialysis; Renal Insufficiency, Chronic; Risk Assessment; Risk Factors; ROC Curve; Time Factors

Osteoprotegerin, a potent osteoclast activation inhibitor, decreases bone resorption and positively affects bone mineral density. This study examined the association between serum osteoprotegerin levels and bone loss in patients with chronic kidney disease, a condition associated with increased risk of mineral and bone disorders. The bone mineral densities of the lumbar spine, total hip, and femur neck were assessed by dual-energy X-ray absorptiometry; serum osteoprotegerin levels were measured at baseline for 1,423 patients enrolled in the prospective KoreaN cohort study for Outcome in patients With Chronic Kidney Disease (KNOW-CKD). Patients aged ≥50 years and with a T-score ≤ -2.5 were diagnosed as having osteoporosis. Multivariable linear regression analysis indicated independent association between serum osteoprotegerin levels and decreased bone mineral density in the lumbar spine (B: -0.489, 95% confidence interval [CI]: -0.883 to -0.095, P = 0.015), and total hip (B: -0.349, 95% CI: -0.672 to -0.027, P = 0.027). However, bone mineral density of the femur neck was not associated with serum osteoprotegerin levels in women. After adjustments, no independent association was found between serum osteoprotegerin levels and bone mineral density in men. In multivariable logistic regression analysis, serum osteoprotegerin levels were associated with increased risk of osteoporosis in women (odds ratio [OR]: 4.72, 95% CI: 1.35 to 16.52, P = 0.015), but not in men (OR: 0.21; 95% CI: 0.04 to 1.31, P = 0.095). To summarize, in female patients with chronic kidney disease, increased serum osteoprotegerin levels were independently associated with decreased bone mineral density in the lumbar spine and total hip, and with increased risk of osteoporosis. Therefore, the measurement of serum osteoprotegerin concentration might be useful as a surrogate marker for determining bone loss in patients with chronic kidney disease, especially for women, although not so much for men.

Topics: Adult; Bone Density; Bone Resorption; Cohort Studies; Demography; Female; Humans; Male; Middle Aged; Multivariate Analysis; Osteoporosis; Osteoprotegerin; Regression Analysis; Renal Insufficiency, Chronic; Republic of Korea; Risk Factors; ROC Curve; Treatment Outcome

Chronic kidney disease-mineral and bone disorder (CKD-MBD) ranks among clinically and pathogenetically significant complications in patients with CKD. Numerous factors are involved in its development, and histomorphometric analysis of the bone tissue is still necessary for accurate diagnosis.. The open, pilot, prospective study aimed at performing a comprehensive histomorphometric bone analysis in 26 dialysis patients and assessing the relationships of different types of CKD-MBD to selected parameters of calcium and phosphate metabolism, densitometry, activity of parathyroid glands, presence of diabetes mellitus, and duration of dialysis treatment.. Comparison of the histomorphometric characteristics demonstrated statistically significant correlations between the volume of bone trabeculae and s-procollagen 1 (.754) as well as s-calcitonin (.856). Similarly, there was a positive correlation between the size of tetracycline lines and volume of bone trabeculae (.705) and a strong negative correlation with the thickness of trabeculae (-.442). When assessing the serum levels of s-osteoprotegerin and serum RANKL, there was a correlation with osteoid thickness and bone trabeculae thickness. In case of s-osteoprotegerin, a statistical power was demonstrated in relation to osteoid thickness (.880); in case of s-RANKL, a statistical power was demonstrated in relation to the thickness of trabeculae (.830). When assessing the influence of dialysis duration, relationships to the volume of trabecular bone (.665) and volume of bone trabeculae (.949) were demonstrated. Finally, a relationship between s-1,25-hydroxyvitamin D and s-osteoprotegerin was observed (.739); also the relationships demonstrated were significantly lower volume of bone trabeculae in men (p = 0.067) and lower values of s-osteocalcin and s-procollagen 1 in diabetic patients (p = 0.014).. The results provide new noninvasive possibilities of CKD-MBD detection that are based on selected serum parameters of bone metabolism. Presented are possibilities of noninvasive assessment of different types of CKD-MBD using serum osteomarkers in relation to comprehensive CKD-MBD histomorphometry.

Topics: Aged; Biomarkers; Bone and Bones; Bone Density; Calcitriol; Calcium; Cardiovascular Diseases; Chronic Kidney Disease-Mineral and Bone Disorder; Czech Republic; Female; Humans; Kidney; Male; Osteocalcin; Osteoprotegerin; Parathyroid Hormone; Pilot Projects; Prospective Studies; RANK Ligand; Renal Dialysis; Renal Insufficiency, Chronic; Reproducibility of Results; Risk Factors

The objective of the study was to determine the relationship between common carotid artery intima-media thickness (CCA-IMT) and histologically assessed calcification of radial artery in relation to clinical features and laboratory markers of bone and mineral metabolism, inflammation, and oxidative stress in patients with stage 5 chronic kidney disease (CKD).. The study comprised 59 patients (36 hemodialyzed, 23 predialysis). CCA-IMT was measured by ultrasonography; the biochemical parameters examined were assessed using routine laboratory methods, ELISA micro-plate immunoassays and spectrophotometry. Fragments of radial artery obtained during creation of hemodialysis access were cryosectioned and stained for calcifications using von Kossa method and alizarin red.. Glucose, osteoprotegerin, pentraxin 3 and Framingham risk score significantly correlated with CCA-IMT. In multiple regression analysis, OPG positively predicted CCA-IMT. Radial artery calcifications were found in 34 patients who showed higher CCA-IMT (0.98 ± 0.13 vs 0.86 ± 0.14 mm; P = 0.006). Higher CCA-IMT values were also associated with more advanced calcifications. CCA-IMT and the presence of plaques in common carotid artery were positive predictors of radial artery calcifications, independent of dialysis status, Framingham risk score, CRP and Ca x Pi [OR for calcifications 2.19 (1.08-4.45) per 0.1 mm increase in CCA-IMT]. The presence of radial artery calcifications was a significant predictor of mortality, independent of dialysis status and Framingham risk score [HR 3.16 (1.03-9.64)].. In CKD patients, CCA-IMT examination can be used as a surrogate measure to assess the incidence and severity of arterial medial calcification which is associated with poor clinical outcome in these patients.

Topics: Adult; Aged; Aged, 80 and over; alpha-2-HS-Glycoprotein; Blood Glucose; C-Reactive Protein; Cardiovascular Diseases; Carotid Artery, Common; Carotid Intima-Media Thickness; Cohort Studies; Coronary Artery Disease; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Humans; Incidence; Inflammation; Insulin Resistance; Interleukin-6; Kidney Failure, Chronic; Logistic Models; Middle Aged; Multivariate Analysis; Osteocalcin; Osteopontin; Osteoprotegerin; Oxidative Stress; Radial Artery; Renal Dialysis; Renal Insufficiency, Chronic; Risk Assessment; Serum Amyloid P-Component; Severity of Illness Index; Tunica Media; Vascular Calcification

Chronic kidney disease (CKD) is often observed among patients with type 2 diabetes mellitus (T2DM) and diabetic foot (DF) leading to end stage renal disease. The aim of this pilot study was to determine genetic and environmental factors involved in the etiology of CKD among patients with DF. The following polymorphisms were studied: rs1800469, rs759853, rs1553005, rs1799983, rs1801133, rs3134069, rs2073618, rs8192678, rs6330, rs11466112, rs121917832 in terms of alleles distribution in patients with DF and T2DM, with or without CKD. The study includes 101 patients with T2DM and DF. Studied groups were divided into 39 individuals with CKD (cases) and 62 controls, depending on the presence of kidney failure defined as eGFR < 60ml/min/1.73m(2) and coexistence of microalbuminuria > 30 mg/dl in at least 3 urine samples. Cases and controls were matched according to mean age, gender, mean duration of T2DM, mean duration of insulin therapy, mean duration of DF cholesterol levels and smoking frequencies. The study showed that CKD risk factors were the following variables: creatinine level, body weight, hips circumference, ischemic heart disease, hypertension and diabetic retinopathy. Moreover, the results suggest the protective role of the allele C of rs3134069 polymorphism in CKD development in patients with T2DM and DF in the following allelic variants: [AA] vs. [AC] and [AA] vs. [AC + CC]. The allele C was observed to be less frequent than the allele A in patients with T2DM and DF. None of the other following polymorphisms was observed to be a potential risk factor of CKD in T2DM and DF population: rs6330, rs759853, rs1553005, rs1799983, rs1801133, rs1800469, rs8192678, rs11466112, rs121917832. We concluded that the rs3134069 polymorphism seems to be the most likely protective genetic factor in CKD development in patients with T2DM and DF.

Topics: Aged; Alleles; Case-Control Studies; Diabetes Mellitus, Type 2; Diabetic Foot; Female; Genetic Predisposition to Disease; Humans; Hypoglycemic Agents; Insulin; Male; Middle Aged; Osteoprotegerin; Pilot Projects; Polymorphism, Single Nucleotide; Renal Insufficiency, Chronic; Risk Factors

Fractures are common in men and women with chronic kidney disease (CKD) but the best tool to identify those at high risk is unknown. Increased circulating osteoprotegerin(OPG) is associated with fractures in postmenopausal women. We determined if serum OPG was associated with prevalent fractures (self-reported low trauma fractures since 40 years of age and/or prevalent vertebral fractures identified by radiographs) in men (n = 97) and women (n = 67) with stage 3–5 CKD. Analyses were performed unadjusted and adjusted for stage of CKD. Results are expressed as mean ± standard deviation(SD), and as odds ratio (OR) per SD increase in OPG with 95 % confidence intervals (CI). The mean age was 62.7 ± 16.3 years, and mean weight was 78.9 ± 18.7 kg. Compared to those without fractures, those with fractures(n = 55) were older (p < 0.01). Serum OPG increased as kidney function decreased, and OPG was higher in those with fractures compared to those without (9.42 ± 4.08 vs 8.06 ± 3.11 pmol/L, p = 0.02). After adjusting for stage of CKD, increased OPG was associated with an increased fracture risk (OR 1.13, 95 % CI 1.02–1.25); however, OPG did not discriminate fracture status well (area under the receiver operating characteristic curve 0.61, 95 % CI 0.52–0.70). OPG is associated with fractures in men and women with stage 3–5 CKD; however, the ability of OPG to discriminate fracture status is poor and cannot be used in isolation to assess fracture risk. Further studies should examine the ability of OPG in combination with other risk factors to better discriminate fracture status in men and women with CKD.

Topics: Aged; Calcium; Female; Fractures, Bone; Humans; Male; Middle Aged; Osteoprotegerin; Parathyroid Hormone; Phosphates; Renal Insufficiency, Chronic

To study the role of the bone mineral metabolic mediators osteoprotegerin (OPG) and fibroblast growth factor 23 (FGF-23) in the mechanisms of cardiovascular events (CVEs) in chronic kidney disease (CKD).. Sixty-eight patients (30 men and 38 women) aged 38 to 64 years (mean age 49 +/- 6.3 years) with Stages III-VD CKD were examined. The stages of CKD were determined in accordance with the NKF-K/DOQI guidelines; glomerular filtration rate was calculated using the CKD-EPI formula. Serum OPG and FGF-23 were examined in all the patients, by applying commercial enzyme immunoassay kits. Doppler echocardiography was performed to evaluate the morphofunctional state of the left ventricle (LV).. As renal failure progressed from Stage III to Stage VD CKD, the examined patients had higher serum OPG and FGF-23 concentrations. The levels of OPG and FGF-23 and the morphofunctional indicators of LV lesion, blood pressure, and anemia showed a strong direct correlation that preserved its significance in analyzing the factors in question in relation to the function of the kidneys and the pattern of cardiovascular system lesion.. The morphogenetic proteins OPG and FGF-23 seem to play a significant role not only in bone remodeling processes, but also in the development of CVEs in CKD.

Topics: Adult; Cardiovascular Diseases; Disease Progression; Echocardiography, Doppler; Female; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Humans; Male; Middle Aged; Osteoprotegerin; Renal Insufficiency, Chronic; Severity of Illness Index

Osteoprotegerin (OPG) regulates bone mass by inhibiting osteoclast differentiation and activation, and plays a role in vascular calcification. We evaluated the relationship between osteoprotegerin levels and inflammatory markers, atherosclerosis, and mortality in patients with stages 3-5 chronic kidney disease. A total of 145 subjects (median age 61 years, 61% men; 36 patients on hemodialysis, 55 patients on peritoneal dialysis, and 54 patients with stages 3-5 chronic kidney disease) were studied. Clinical characteristics, markers of mineral metabolism (including fibroblast growth factor-23 [FGF-23]) and inflammation (high-sensitivity C-reactive protein [hsCRP] and interleukin-6 [IL-6]), and the intima-media thickness (IMT) in the common carotid arteries were measured at baseline. Cardiac function was assessed by color tissue Doppler echocardiography. After 36 months follow-up, the survival rate by Kaplan-Meier analysis was significantly different according to OPG levels (χ ² =14.33; P=0.002). Increased OPG levels were positively associated with IL-6 (r=0.38, P<0.001), FGF-23 (r=0.26, P<0.001) and hsCRP (r=0.0.24, P=0.003). In addition, OPG was positively associated with troponin I (r=0.54, P<0.001) and IMT (r=0.39, P<0.0001). Finally, in Cox analysis, only OPG (HR=1.07, 95%CI=1.02-1.13) and hsCRP (HR=1.02, 95%CI=1.01-1.04) were independently associated with increased risk of death. These results suggested that elevated levels of serum OPG might be associated with atherosclerosis and all-cause mortality in patients with chronic kidney disease.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Atherosclerosis; Biomarkers; Brazil; C-Reactive Protein; Carotid Intima-Media Thickness; Cause of Death; Echocardiography, Doppler; Female; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Heart Function Tests; Humans; Interleukin-6; Kaplan-Meier Estimate; Male; Middle Aged; Multivariate Analysis; Osteoprotegerin; Renal Insufficiency, Chronic; Risk; Severity of Illness Index; Young Adult

The increased awareness of the potential role played by mineral and bone disorder in the appearance of cardiovascular disease in renal patients has produced research efforts aimed at discovering possible pathogenic links. Accordingly, the diagnostic significance of the classic bone markers of mineral disorders and of the new markers in the setting of chronic kidney disease-mineral and bone disorders (CKD-MBD) needs to be re-evaluated along with increasing information. In this article we include classic markers of bone metabolism and some of the noncollagenous bone proteins that are gaining experimental and clinical significance in CKD-MBD. Among classic markers of secondary hyperparathyroidism and of renal osteodystrophy, we analyzed parathyroid hormone, alkaline phosphatase, tartrate-resistant acid phosphatase, and bone collagen-derived peptides. We underlined, for each, the relevance of parent proteins (peptides or isoforms) that affect assay methods and, eventually, the diagnostic or prognostic significance. Also, we considered their relationship with cardiovascular mortality. Among the numerous noncollagenous bone proteins, we examined matrix Gla protein (MGP), osteocalcin (OC), osteoprotegerin, and the small integrin-binding ligand N-linked glycoprotein family. For MGP and OC we report the relevant involvement with the process of calcification (MGP) and with glucose and energy metabolism (OC). Both of these proteins require vitamin K to become active and this is a specific problem in renal patients who frequently are deficient of this vitamin. Finally, recent acquisitions on the fascinating family of the small integrin-binding ligand N-linked glycoprotein proteins are recapitulated briefly to underline their potential clinical interest and their complex involvement with all aspects of CKD-MBD. Their diagnostic role in clinical practice awaits further studies.

Topics: Acid Phosphatase; Alkaline Phosphatase; Animals; Biomarkers; Calcium-Binding Proteins; Chronic Kidney Disease-Mineral and Bone Disorder; Extracellular Matrix Proteins; Humans; Hyperparathyroidism, Secondary; Isoenzymes; Matrix Gla Protein; Osteocalcin; Osteoprotegerin; Parathyroid Hormone; Peptide Fragments; Procollagen; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Renal Insufficiency, Chronic; Tartrate-Resistant Acid Phosphatase

Arterial thickening contributes to elevated cardiovascular risk in patients on maintenance renal replacement therapy. The common carotid artery intima-media thickness (CCA-IMT) is an early atherosclerotic marker and may be used to assess the stratification of atherosclerotic advancement and resultant arterial calcification.. The aim of the study was to evaluate the associations between atherosclerotic changes in the common carotid arteries expressed as the CCA-IMT and the body mass index (BMI), serum lipid levels, C‑reactive protein (CRP), and selected bone metabolism parameters including phosphorus, calcium, intact parathormone (iPTH), alkaline phosphatase, osteopontin, osteoprotegerin, osteocalcin, fetuin A, and fibroblast growth factor‑23 (FGF‑23) in patients treated with peritoneal dialysis.. The study included 67 patients with chronic kidney disease (36 men and 31 women) aged 53 ±13 years (range, 19-75 years) treated with peritoneal dialysis for 30 ±24 months. The CCA‑IMT was assessed by ultrasonography using Acuson 128/10 XP. The BMI was calculated using the Quetelet formula. Serum lipid levels, phosphorus, calcium, iPTH, alkaline phosphatase, and CRP were measured using standard laboratory methods, while fetuin A, osteocalcin, osteoprotegerin, osteopontin, and FGF‑23 using commercial enzyme‑linked immunosorbent assay kits.. Positive correlations were observed between CCA-IMT and age (r = 0.54, P <0.0001), BMI (r = 0.39, P = 0.003), and osteoprotegerin (r = 0.38, P = 0.004). In a multiple regression analysis, age (r = 0.41, P = 0.01), osteocalcin (r = 0.34, P = 0.04), and log‑transformed osteoprotegerin values (r = 0.38, P = 0.02) remained independently associated with the CCA-IMT. The highest CCA‑IMT values (0.85 ±0.21) were observed in patients with osteoprotegerin concentrations in the upper tertile. Osteoprotegerin concentrations strongly and positively correlated with the duration of dialysis treatment (r = 0.55, P <0.0001).. The CCA‑IMT has been shown to be a reliable noninvasive measure of subclinical atherosclerosis and, therefore, of associated increased vascular risk. Elevated serum osteoprotegerin levels may be useful as a prognostic marker of cardiovascular risk in dialyzed patients.

Topics: Adult; Aged; Atherosclerosis; Biomarkers; Body Mass Index; C-Reactive Protein; Cardiovascular Diseases; Carotid Artery, Common; Carotid Intima-Media Thickness; Female; Fibroblast Growth Factor-23; Humans; Lipids; Male; Middle Aged; Osteoprotegerin; Peritoneal Dialysis; Prognosis; Renal Insufficiency, Chronic; Risk Factors

Urinary exosomes have been proposed as potential diagnostic tools. TNF superfamily cytokines and receptors may be present in exosomes and are expressed by proximal tubular cells. We have now studied the expression of selected TNF superfamily proteins in exosome-like vesicles from cultured human proximal tubular cells and human urine and have identified additional proteins in these vesicles by LC-MS/MS proteomics. Human proximal tubular cells constitutively released exosome-like vesicles that did not contain the TNF superfamily cytokines TRAIL or TWEAK. However, exosome-like vesicles contained osteoprotegerin (OPG), a TNF receptor superfamily protein, as assessed by Western blot, ELISA or selected reaction monitoring by nLC-(QQQ)MS/MS. Twenty-one additional proteins were identified in tubular cell exosome-like vesicles, including one (vitamin D binding protein) that had not been previously reported in exosome-like vesicles. Twelve were extracellular matrix proteins, including the basement membrane proteins type IV collagen, nidogen-1, agrin and fibulin-1. Urine from chronic kidney disease patients contained a higher amount of exosomal protein and exosomal OPG than urine from healthy volunteers. Specifically OPG was increased in autosomal dominant polycystic kidney disease urinary exosome-like vesicles and expressed by cystic epithelium in vivo. In conclusion, OPG is present in exosome-like vesicles secreted by proximal tubular epithelial cells and isolated from Chronic Kidney Disease urine.

Topics: Adult; Aged; Aged, 80 and over; Amino Acid Sequence; Cell Line; Cytokine TWEAK; Exosomes; Female; Humans; Kidney Tubules, Proximal; Male; Middle Aged; Molecular Sequence Data; Osteoprotegerin; Renal Insufficiency, Chronic; TNF-Related Apoptosis-Inducing Ligand; Tumor Necrosis Factors

Topics: Cardiovascular Diseases; Female; Humans; Male; Osteoprotegerin; Renal Dialysis; Renal Insufficiency, Chronic; Vascular Stiffness

Osteoprotegerin (OPG) and fetuin-A are vascular calcification regulators that may be related to high cardiovascular (CV) mortality in hemodialysis (HD) patients. We evaluated the relationship between OPG, fetuin-A, and pulse wave velocity (PWV), a marker of vascular stiffness, and determined whether OPG and fetuin-A were independent predictors of CV events in HD patients.. We conducted a prospective observational study in 97 HD patients. OPG and fetuin-A were measured at baseline and arterial stiffness was evaluated by PWV. All patients were stratified into tertiles according to serum OPG levels.. A significant trend was observed across increasing serum OPG concentration tertiles for age, HD duration, systolic blood pressure, cholesterol, triglycerides, and PWV. Multiple linear regression analysis revealed that diabetes (β = 0.430, p = 0.000) and OPG levels (β = 0.308, p = 0.003) were independently associated with PWV. The frequency of new CV events was significantly higher in the upper OPG tertiles compared with those in the lower OPG tertiles. In Cox proportional hazards analysis, upper tertiles of OPG levels were significantly associated with CV events (hazard ratio = 4.536, p = 0.011).. Serum OPG, but not fetuin-A, levels were closely associated with increased vascular stiffness, and higher OPG levels may be independent predictors of new CV events in HD patients.

Topics: Adult; Aged; alpha-2-HS-Glycoprotein; Biomarkers; Cardiovascular Diseases; Female; Humans; Kaplan-Meier Estimate; Linear Models; Male; Middle Aged; Multivariate Analysis; Osteoprotegerin; Predictive Value of Tests; Prognosis; Proportional Hazards Models; Prospective Studies; Pulse Wave Analysis; Renal Dialysis; Renal Insufficiency, Chronic; Risk Factors; Up-Regulation; Vascular Stiffness

The increased vascular calcification, cardiovascular morbidity, and mortality in chronic kidney disease (CKD) patients has been associated with disturbances in mineral-bone metabolism. In order to determine markers of the vascular calcification frequently observed in these patients, blood samples of elderly male and female hemodialysis CKD patients were used to measure serum levels of: osteoprotegerin (OPG), total soluble receptor activator of nuclear factor-κB ligand (sRANKL), and fetuin-A by enzyme immunoassay; tartrate-resistant acid phosphatase (TRACP-5b), and bone-specific alkaline phosphatase (BAP) by immunoenzymometric assay; osteocalcin (OC) by ELISA; iPTH by immunoradiometric assay; 25(OH)D(3) and 1,25(OH)(2)D(3), by I(125) radioimmunoassay; and calcium and phosphorus by photometric assay. Serum OPG, BAP, iPTH, phosphorus, and OC levels were higher and serum 25(OH)D(3), 1,25(OH)(2)D(3), and fetuin-A levels lower in both male and female CKD patients than in their respective controls. Our results indicate that the bone formation and resorption parameters are altered in elderly male and female hemodialysis CKD patients. These changes may lead to vascular calcifications and cardiovascular complications, given that elevated OPG and OC levels and reduced fetuin-A levels are associated with cardiovascular events.

Topics: Acid Phosphatase; Aged; Alkaline Phosphatase; alpha-2-HS-Glycoprotein; Biomarkers; Cardiovascular Diseases; Female; Humans; Isoenzymes; Male; Middle Aged; Osteoprotegerin; RANK Ligand; Renal Dialysis; Renal Insufficiency, Chronic; Tartrate-Resistant Acid Phosphatase; Vascular Calcification