Role of osteoprotegerin in vascular disorders of the end-stage renal disease patients.

AIM: To assess the osteoprotegerin (OPG) relationship with cardiovascular complications in hemodialysis (HD) patients. METHODS: The study included 87 HD patients. Clinical characteristics, ankle-arm index (AAI), OPG and mineral markers levels were recorded. Arterial intimal calcification (AIC) and arterial medial calcification (AMC) were registered. RESULTS: OPG levels were increased in HD patients. Patients with AIC (p = 0.006)/ AMC (p = 0.01) had higher OPG levels. OPG did not have any relation with cardiovascular diseases. OPG correlated positively with age, increased HD vintage and inversely with albumin and AAI. OPG has not been a risk factor for VC or cardiovascular disease. CONCLUSION: OPG rising could be a reaction in defense to vascular aggression, because OPG was associated with VC, but not with vascular disease.

Arterial calcifications and osteoprotegerin in chronic hemodialysis patients: impact on 6-year survival.

AIM: The association between end-stage renal disease and cardiovascular mortality may be influenced through vascular alterations, in particular atherosclerosis and vascular calcification. The study goal was to assess the impact of each type of arterial intimal calcifications (AIC) and arterial medial calcifications (AMC), of osteoprotegerin (OPG), mineral metabolism markers and other features on all-cause and cardiovascular mortality in chronic hemodialysis patients. METHODS: Ultrasound was performed in 87 patients on the carotid and femoral arteries, and the severity of AIC and AMC was assessed calculating a score according to the extension of calcification. We analyzed the link between AIC, AMC, OPG, mineral markers and mortality after 6 years of follow-up. RESULTS: The cutoff value for OPG determined using ROC was 4.9 pmol/l for all-cause and cardiovascular mortality. Patients with higher serum OPG levels presented higher mortality rates. Our study revealed that AIC, high OPG, low ankle-arm index, presence of diabetes, smoking status, and lack of arteriovenous fistula are associated with all-cause and cardiovascular mortality in univariate regression analysis. Multivariate analysis identified AIC scoring based on the segmentation method as an independent predictor of all-cause and cardiovascular mortality, along with increased OPG levels. AMC scoring was not a predictor of mortality. CONCLUSIONS: Identifying and scoring AIC on ultrasound and measuring OPG levels, as a basis of the HD patient assessment may become valuable tools in clinical work, as these have an impact on death toll.

Osteoprotegerin and uremic osteoporosis in chronic hemodialysis patients.

INTRODUCTION: Osteoprotegerin (OPG) is a powerful inhibitor of osteoclast activity, and it plays an important role in bone metabolism. In hemodialysis (HD) patients, the relationship between OPG and bone mineral density (BMD) is important, but remains unclear yet. The study objective was to assess the OPG role related to uremic osteoporosis in HD patients. METHODS: This cross-sectional study has been realized on a cohort of 63 chronic HD patients. INCLUSION CRITERIA: elderly prevalent HD patients with an age over 55 years old. EXCLUSION CRITERIA: previous bone disease or previous renal transplant; neoplasia; parathyroidectomy, hormone replacement therapy. The data regarding demographical and clinical characteristics, including treatments for mineral and cardiovascular complications, were recorded. Serum OPG and mineral markers levels were measured. BMD was assessed by calcaneus quantitative ultrasound; it measured broadband ultrasound attenuation, speed of sound (SOS) and stiffness index (STI). RESULTS: The high OPG levels were associated with higher bone mineral density (OPG-SOS P = 0.003; R = 0.37; OPG-STI P = 0.03; R = 0.28). Malnutrition, anemia and advanced age correlated with bone demineralization. Males had higher bone density parameters than females. In patients treated with vitamin D (P = 0.005), the BMD was increased comparing to patients without these treatments. CONCLUSIONS: OPG levels had directly correlated with bone mineral density parameters. Our study further confirms the critical role of OPG in the pathogenesis of uremic osteoporosis in ESRD. Whether the increased circulant OPG protect against bone loss in patients undergoing HD remains to be established.

FGF-23, vascular calcification, and cardiovascular diseases in chronic hemodialysis patients.

INTRODUCTION: Chronic hemodialysis (HD) patients have bad prognosis and cardiovascular diseases (CVD) represent their main threatening complication. Fibroblast growth factor (FGF-23) has been associated with all kinds of evil consequences, including cardiovascular morbidity, but some studies demonstrated the contrary. Therefore, it is important to know whether FGF-23 is associated with cardiovascular risk or protection. The purpose of this study was to assess the links between FGF-23 and intimal vascular calcification (VC) and with the presence of CVD in chronic HD patients. PATIENTS AND METHODS: This study was carried out on a cohort of randomly selected 88 prevalent HD patients. We recorded demographical, clinical, and biochemical data, including FGF-23. VC was evaluated on carotid ultrasound. CVD were registered. RESULTS: The mean age was 59.68 ± 14.49 years, HD vintage was 59.61 ± 52.39 months, and 20 patients were diabetic (22.72 %). VC was present in 54 patients (61.4 %) and 25 patients (28.4 %) had CVD. FGF-23 correlated positively with HD vintage (r = 0.37; p < 0.001) and iPTH (r = 0.21; p = 0.048). FGF-23 did not correlate with VC score. Patients with CVD were older (p = 0.006), had lower FGF-23 (p = 0.008), higher VC score (p = 0.009), lower Hb (p = 0.008), albumin (p = 0.003), and creatinine (p = 0.03). Low FGF-23 was identified as a risk factor for CVD. CONCLUSION: We report on a novel association between low FGF23 and CVD in chronic HD patients and a lack of correlation of FGF-23 with VC. FGF-23 could play a role in cardiovascular protection that remains to be confirmed in larger studies.

Vascular calcifications and renal osteodystrophy in chronic hemodialysis patients: what is the relationship between them?

INTRODUCTION: Vascular calcifications (VCs) and renal osteodystrophy (ROD) are frequently seen together and represent the major causes of morbidity and mortality in hemodialysis (HD) patients. Some studies suggest a pathogenic link between them, but there is no consensus as yet regarding this issue. The main objective of our study was to establish whether there is any relation between VCs and ROD in our HD patients. We evaluated the prevalence of VCs and ROD and the relationship between VCs and some clinical and biochemical characteristics of HD patients. METHODS: We examined radiological signs of VCs and ROD on hands and pelvis bone radiographs in 81 chronic HD patients, and we calculated a VC score on this basis. RESULTS: We found a significant relation between radiological signs of ROD and those of VC (P = 0.019). The patients with ROD had a higher mean VC score (P = 0.02). By linear regression, the VC score correlated directly with serum calcium (Ca), phosphorus (P), intact parathyroid hormone (iPTH) and CaxP product and inversely with serum albumin. The logistic regression model revealed that ROD, male gender and treatment with calcium salts were predictive of VCs development. There were no associations between VCs and age, HD vintage, diabetes, dialysate Ca concentration, vitamin D treatment, spKt/V, URR and C-reactive protein (CRP) levels. CONCLUSION: There seems to be a pathogenetic link between bone and artery diseases in chronic HD patients. Both VCs and ROD have a high prevalence. ROD, male gender and treatment with calcium salts are risk factors for VCs.