Estrella Ruiz-Requena

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)D3 and 1,25(OH)2D3, by I125 radioimmunoassay; and calcium and phosphorus by photometric assay. Serum OPG, BAP, iPTH, phosphorus, and OC levels were higher and serum 25(OH)D3, 1,25(OH)2D3, 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.

Can the Use of Growth Hormone Reduce the Postoperative Fatigue Syndrome

Abstract. Convalescence after surgery is characterized by a period of fatigue (POF). If we assume that the POF syndrome has a multifactorial etiology, it is clear that the aim of therapeutic measures should be to reduce the response to surgical stress. The purpose of the present study was to determine if administering exogenous human growth hormone (hGH) can prevent the development or reduce the duration of the POF. We carried out a placebo-controlled randomized double-blind trial with 48 patients after elective cholecystectomy (placebo, or control group,n = 26; hGH-treated group,n = 22). Eligibility criteria were strict so as to introduce as few variables as possible. The results obtained in the study show that for moderate surgical injury (cholecystectomy in metabolically healthy subjects) the administering of low doses of hGH (8 IU/day) minimized the POF syndrome (Christensen score). Furthermore, a positive nitrogen balance was achieved in the hGH-treated group during the postoperative period from the first 24 hours onward. This finding correlates with the significant increase in serum levels of hGH (p < 0.05) and insulin-like growth factor 1 (IGF-1) (p < 0.001). On the other hand, anthropometric measurements in the hGH-treated group revealed a slight but continuous decrease in body weight and thickness of the triceps skinfold; however, arm muscle circumference did not significantly change during the postoperative period. These findings are related to the effects of the application of exogenous growth hormone, which preserves or increases lean body mass and reduces adipose tissue mass. The serum transferrin level proved to be a reliable biochemical indicator of POF.

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

Abstract 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.

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.

Dehydroepiandrosterone Sulfate and Growth Axis Hormones in Patients with Ischemic Heart Disease

Background: The present study aimed to determine whether decreases in dehydroepiandrosterone sulfate (DHEA-S) and growth axis components precede cardiovascular disease or are a consequence of it. Methods: We measured the concentrations in serum of DHEA-S, ACTH, cortisol, growth hormone, insulin-like growth factor-1 and insulin-like growth factor-binding protein-3 in 30 male controls and also in 37 male patients on days 0, 2, 5, 7 and 9 after suffering a myocardial infarction (MI). Results: There was no significant variation in any of these parameters between the controls and the patients on day 0. However, we found a significant (p < 0.001) reduction in the DHEA-S concentrations of the patients between day 0 and subsequent days (days 2, 5, 7and 9). Conclusion: We conclude that the decrease in DHEA-S in patients with MI is a consequence and not a cause of the disease.

Effects of Exogenous Growth Hormone in Postoperative Immune Function and Other Clinical Outcomes

The use of human growth hormone (hGH) in humans as a means of inducing nitrogen storage is attractive to the surgeon, since he or she is continually confronted with patients who could regain their health if only a means were found to heal their wounds and reverse their protein malnutrition. This can be done by providing an adequate intake of nitrogen and by activating an endocrine mechanism that would reverse catabolic predominance.