Biochemical markers of vascular calcification in elderly hemodialysis patients.

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.

A nutritional intervention study with hydrolyzed collagen in pre-pubertal spanish children: influence on bone modeling biomarkers.

AIM: The aim of the study was to investigate the influence of dietary intake of commercial hydrolyzed collagen (Gelatine Royal) on bone remodeling in pre-pubertal children. METHODS: A randomized double-blind study was carried out in 60 children (9.42 +/- 1.31 years) divided into three groups according to the amount of partially hydrolyzed collagen taken daily for 4 months: placebo (G-I, n=18), collagen (G-II, n=20) and collagen+calcium (G-III, n=22) groups. Analyses of the following biochemical markers were carried out: total and bone alkaline phosphatase (tALP and bALP), osteocalcin, tartrate-resistant acid phosphatase (TRAP), type I collagen carboxy-terminal telopeptide, lipids, calcium, 25-hydroxyvitamin D, insulin-like growth factor-1 (IGF-1), thyroid-stimulating hormone, free thyroxin and intact parathormone. RESULTS: There was a significantly greater increase in serum IGF-1 in G-III than in G-II (p < 0.01) or G-I (p < 0.05) during the study period, and a significantly greater increase in plasma tALP in G-III than in G-I (p < 0.05). Serum bALP behavior significantly (p < 0.05) differed between G-II (increase) and G-I (decrease). Plasma TRAP behavior significantly differed between G-II and G-I (p < 0.01) and between G-III and G-II (p < 0.05). CONCLUSION: Daily dietary intake of hydrolyzed collagen seems to have a potential role in enhancing bone remodeling at key stages of growth and development.

Two models of homocysteine behavior in acute myocardial infarction.

OBJECTIVES: To study homocysteine (Hcy) levels during post-infarction follow-up. METHODS AND RESULTS: In this study, serum Hcy levels were measured in 90 healthy individuals and in 127 patients with acute myocardial infarction (MI) on the day of infarction (day 0) and days 2, 5, 7, 9, and 11 post-infarction, comparing Hcy levels in MI patients on day 0 with their follow-up results and with levels in controls. Overall, MI patients had higher Hcy levels on day 0 versus controls. However, the behavior of Hcy levels differed between two groups of MI patients. Thus, patients with similar Hcy levels to controls on day 0 showed significantly higher levels on days 2, 5, 7, 9, and 11 post-infarction than on day 0. In contrast, patients with significant higher Hcy levels than controls on day 0 showed significantly lower levels on days 2, 5, 7, 9, and 11 post-infarction than on day 0. CONCLUSIONS: Different behaviors of Hcy levels in MI patients might correspond to a history or absence of history of asymptomatic myocardial ischemia. Further research is required to test this hypothesis.

Mineral-bone metabolism markers in young hemodialysis patients.

OBJECTIVE: To study the most frequent markers of mineral-bone metabolism in young hemodialysis (HD) patients in order to detect any metabolism changes that could lead to the atherosclerosis and extravascular calcification frequently observed in chronic kidney disease (CKD) patients and estimate their potential prognostic significance. DESIGN AND METHODS: We measured serum levels of intact-PTH (iPTH), Osteoprotegerin (OPG), total soluble receptor activator of nuclear factor-κB ligand (sRANKL), tartrate-resistant acid phosphatase (TRAP-5b), osteocalcin (Oc), bone-specific alkaline phosphatase (BAP), calcium, phosphorus, 25(OH)D(3) and 1,25 (0H)(2)D(3) in young HD patients and controls RESULTS: In comparison to controls, serum OPG, iPTH, BAP, phosphorus, and osteocalcin levels were higher whereas 25(OH)D(3) and 1,25(OH)(2)D(3) were lower in HD patients. CONCLUSION: In conclusion, our results indicate that bone formation and resorption parameters are already altered in young HD subjects. These changes may lead to vascular calcifications and cardiovascular complications, given that elevated OPG levels predict cardiovascular events in HD patients. Furthermore, low levels of vitamin D metabolites have been associated with the presence of vascular calcification.

Dehydroepiandrosterone sulfate and growth axis hormones in patients after surgery.

We selected 38 patients scheduled for cholecystectomy and studied their serum concentrations of dehydroepiandrosterone (DHEA) and growth axis hormones [growth hormone/insulin-like growth factor-1 (GH/IGF-1)]. We aimed to determine whether alterations in these concentrations resulted from surgical stress or, on the contrary, preceded surgery and were themselves a cause of chronic diseases that reduce life expectancy. We measured the serum concentrations of DHEA sulfate (DHEA-S), ACTH, cortisol, human GH (hGH), IGF-1, and IGF-1 binding protein-3 (IGFBP-3) preoperatively and then 2 and 7 days after surgery; we also compared the preoperative findings with those of a healthy control group. The results were analyzed by gender because DHEA and GH/IGF-1 are known to present sexual dimorphism. There were no significant differences between the preoperative and control results for any of the parameters studied. We found a significant reduction in the concentrations of DHEA-S and IGF-1 on days 2 and 7 after surgery versus the preoperative values. We conclude that the decrease in DHEA-S in patients after surgery is a result of surgical trauma and does not precede surgical stress. The decrease in hormone levels observed in patients with chronic disease may therefore be a result, not a cause, of disease, as some have claimed. Further studies with a later endpoint would be of interest to assess any subsequent return of DHEA-S levels to baseline measurements.

Follicular fluid markers of oocyte developmental potential.

BACKGROUND: Concentrations of certain substances in follicular fluid (FF) are related to fertilization outcome and early post-fertilization development. The study aim was to identify FF markers with which to predict embryo implantation potential. METHODS: Concentrations of selected hormones, cytokines and growth factors in individual FF samples obtained during assisted reproduction treatment were related with treatment outcomes. RESULTS: Mean concentrations of LH, growth hormone (GH), prolactin (PRL), 17beta-estradiol (E2) and insulin-like growth factor (IGF)-I were higher, and that of interleukin-1 (IL-1) was lower, in treatment attempts leading to a clinical pregnancy as compared with those in which no pregnancy was established. Concentrations of FSH, progesterone, tumour necrosis factor-alpha and IGF-II were similar in successful and unsuccessful attempts. In successful attempts, LH and GH levels were higher in those follicles from which oocytes giving rise to transferred embryos (i.e. embryos with best morphology and fastest cleavage rate) originated, as compared with other follicles from which a mature oocyte was recovered but was cryopreserved for later use. CONCLUSIONS: FF levels of LH, GH, PRL, E2, IGF-I and IL-1 may serve to analyse cases of repeated assisted reproduction failures and to assess effects of modifications of the ovarian stimulation protocol.