Adolfo Romeo

Effects of the phytoestrogen genistein on cardiovascular risk factors in postmenopausal women.

Objective: The phytoestrogen genistein has been shown to be the most efficacious in clinical and experimental studies. We studied whether genistein treatment affects some cardiovascular risk markers in postmenopausal women. Design: Sixty healthy postmenopausal women, who were 52 to 60 years of age, were enrolled in a 6-month double-blind, placebo-controlled, randomized study. After a 4-week stabilization on a standard fat-reduced diet, participants were randomly assigned to receive either genistein (n = 30; 54 mg/d) or placebo (n = 30). At baseline and after a 6-month treatment, we measured fasting glucose, insulin, insulin resistance (HOMA-IR), osteoprotegerin (OPG), fibrinogen, and sex hormone-binding globulin (SHBG). Results: By comparison with placebo, genistein treatment decreased significantly fasting glucose (genistein = −8.7 ± 2.3%; placebo = 3.2 ± 2.3%; P < 0.001), fasting insulin (genistein = −12 ± 3.33%; placebo = 36 ± 3.29%; P < 0.001), and HOMA-IR (genistein = −14 ± 5.8%; placebo = 42 ± 0.6%; P < 0.001). After genistein-treatment, fibrinogen decreased (genistein = 3.18 ± 0.12 g/L; placebo = 3.83 ± 0.04 g/L; P < 0.001) with respect to placebo. In the genistein group, serum OPG was lower (−2 ± 0.3%) than in placebo (9 ± 1.5%; P < 0.001), and serum SHBG was higher (63 ± 3.8 nmol/L) compared with placebo (53 ± 2.9 nmol/L; P < 0.05). Conclusion: Our study suggests that genistein may have a favorable effect on some cardiovascular markers.

Effects of homocysteine on proliferation, necrosis, and apoptosis of vascular smooth muscle cells in culture and influence of folic acid.

BACKGROUND It is known that hyperhomocysteinemia is associated with an increased risk of vascular disease, yet little is known about the pathogenic mechanisms underlying the action of homocysteine (Hcy) itself. METHODS We evaluated the effects of Hcy on cell proliferation, apoptosis, and necrosis in smooth muscle cells (SMCs) cultured for 24 h with different amounts of Hcy. The percentage of apoptotic and necrotic cells from the culture was evaluated using two different techniques: annexin V-FITC and propidium iodide (PI) fluorescence and apoptosis TUNEL assay. RESULTS The addition of 10 microM/l of Hcy to the medium was followed by a significant increase in cell proliferation and death, through apoptosis and necrosis, respectively. Notwithstanding this apparent balance, a significant increase was found in the total number of cells present in Hcy-treated culture, thus demonstrating a positive dose-dependent correlation with Hcy concentrations in the culture medium. The addition of folic acid to the culture medium significantly reduced both Hcy concentrations in media and the effects of Hcy on the proliferation/apoptosis/necrosis balance of cells in culture. The percentages for apoptotic cells and for cells with a necrotic morphology continued to increase as Hcy concentrations increased, although the absolute values were lower in the culture treated than in that not treated with folic acid. CONCLUSIONS In the presence of folic acid, at increasing concentrations of Hcy, the total number of cells in culture showed increases far less relevant with respect to the control. Also the percentage of apoptotic cells to that of cells with a necrotic morphology, although conserving the tendency to increase to growth of the concentrations of Hcy, have shown absolute values that were lower in the folic acid-treated cultures.

Neutrophil gelatinase-associated lipocalin (NGAL) reflects iron status in haemodialysis patients

BACKGROUND An iron deficiency is often present in haemodialysis (HD) patients; however, although transferrin saturation (TSAT) of <20% and/or serum ferritin of <200 ng/mL should express iron scarcity, in HD patients high ferritin levels could be related to inflammation rather than reflecting optimal iron stores. METHODS The aim of the present study was to evaluate serum levels of neutrophil gelatinase-associated lipocalin (NGAL), a small siderophore-binding protein, in a cohort of 56 chronic HD patients in order to determine its possible relationships with iron status. RESULTS NGAL levels were markedly higher in HD patients than in healthy controls; furthermore, HD patients with TSAT <20% had lower NGAL values than healthy controls, whereas the correction of iron deficiency by means of chronic i.v. iron administration significantly increased NGAL values from baseline. Findings from univariate and multivariate analyses demonstrated that NGAL was a significant predictor of hsCRP, spKT/V and TSAT. In ROC analysis, a NGAL cut-off level of <or=473 ng/mL had a greater sensitivity and specificity than a ferritin level of <200 ng/mL in identifying iron deficiency among HD patients. CONCLUSIONS The findings demonstrated that HD patients have altered NGAL values probably because this protein is involved in the maintenance of iron equilibrium. Finally, NGAL might be proposed as a new tool in the assessment of iron deficiency and in the management of iron therapy for HD patients.

Effect of a Single Intravenous Immunoglobulin Infusion on Neutrophil Gelatinase-Associated Lipocalin Levels in Proteinuric Patients With Normal Renal Function

ABSTRACT The aim of the present study was to evaluate levels of neutrophil gelatinase-associated lipocalin (NGAL), a stress protein increased after renal and systemic stimuli, in a cohort of 15 patients with severe proteinuria secondary to idiopathic membranous nephropathy and conserved renal function. Neutrophil gelatinase-associated lipocalin levels and the fractional excretion of this protein were higher in patients than in healthy controls. Furthermore, a close correlation was found between serum NGAL and urinary (uNGAL) (r = 0.81; P < 0.01) and between uNGAL and daily proteinuria (r = 0.44; P < 0.03). One hour after infusion of a single high-dose bolus of intravenous immunoglobulin (0.4 g/kg), a new and promising therapy for several kidney diseases, a marked reduction was found in NGAL levels (serum NGAL 194.1 ± 121 vs 370.1 ± 180.5 ng/mL, P < 0.05; urinary NGAL 153.3 ± 108.6 vs 502.2 ± 293.4 ng/mL, P < 0.03); this was maintained 24 hours after the treatment. The findings made suggest that the NGAL balance is altered in patients with severe proteinuria who have not yet developed overt chronic renal failure, thus confirming the potential use of this protein as an early biomarker of kidney damage preceding the increase in serum creatinine levels. Furthermore, also extra-renal cells (neutrophils, endothelium) may hyper-release NGAL, expressing systemic stress related to severe proteinuria. This would explain the impressive decrease occurring in NGAL values after intravenous immunoglobulin infusion, thus providing further evidence of the antiinflammatory properties of this particular therapeutic approach and indicating the possible value of NGAL measurement in monitoring the efficacy of treatment of renal diseases.

Aquaretic Agents: Whats Beyond the Treatment of Hyponatremia?

Unlike the more commonly used diuretics, aquaretic agents can induce an increase in urinary volume without incurring a loss of electrolytes. These molecules belong to a family of vasopressin receptor antagonists, V2 in particular, that regulate optional renal water re-absorption via the synthesis and expression of aquaporin-2. In view of their properties, they have become the agent of choice in the treatment of hyponatremic states with water retention, and different studies have demonstrated that they are more effective and practical to use than other traditional approaches in the treatment of diseases such as cirrhosis-related ascites, SIADH and, above all, heart failure. However, the future probably holds the promise of new and unexpected applications for this type of drug in the treatment of several conditions, including polycystic kidney and glomerular disease, glaucoma and Menieres syndrome.

QTc interval and QTc dispersion during haemodiafiltration

Background and Aim:  Our aim was to evaluate QTc interval and QTc dispersion in 27 end‐stage renal disease (ESRD) patients undergoing Acetate Free Biofiltration (AFB) in order to ascertain any correlations between the electrrocardiographic (ECG) parameters, serum Na+, K+, Ca++, Mg++ and intraerythrocytic Mg++ (Mg++e) concentrations. All measures were made at t0 (session beginning), t1 (first hour), t2 (second hour), t3 (third hour), and t4 (session end).

Arrhythmias and Hemodialysis: Role of Potassium and New Diagnostic Tools

Cardiovascular diseases represent the main causes of death in patients affected by renal failure, and arrhythmias are frequently observed in patients undergoing hemodialysis. Dialytic treatment per se can be considered as an arrhythmogenic stimulus; moreover, uraemic patients are characterized by a “pro-arrhythmic substrate” because of the high prevalence of ischaemic heart disease, left ventricular hypertrophy and autonomic neuropathy. One of the most important pathogenetic element involved in the onset of intra-dialytic arrhythmias is the alteration in electrolytes concentration, particularly calcium and potassium. It may be very useful to monitor the patients cardiac activity during the whole hemodilaytic session. Nevertheless, the application of an extended intradialytic electrocardiographic monitoring is not simple because of several technical and structural impairments. We tried to overcome these difficulties using Whealthy®, a wearable system consisting in a t-shirt composed of conductors and piezoresistive materials, integrated to form fibers and threads connected to tissutal sensors, electrodes, and connectors. ECG and pneumographic impedance signals are acquired by the electrodes in the tissue, and the data are registered by a small computer and transmitted via GPRS or Bluetooth.

Neutrophil gelatinase-associated lipocalin levels in chronic haemodialysis patients

Neutrophil gelatinase‐associated lipocalin (NGAL), a small 25 kDa protein strongly induced in injured renal tubular cells, represents an interesting emerging biomarker in the field of clinical nephrology. The aim of the present pilot study was to analyze circulating NGAL levels in a small cohort of 30 patients on chronic haemodialysis (HD), in order to assess any relationships with different laboratory and clinical parameters. Pre‐ and post‐HD levels were higher in patients than in healthy subjects (485.2 ± 49.7 vs 51.2 ± 4.6 ng/mL; P < 0.001; and 167.4 ± 48.0 vs 51.2 ± 4.6 ng/mL; P = 0.01). Furthermore, a single HD session decreased NGAL levels by approximately fourfold (485.2 ± 49.7 vs 167.4 ± 48.0 ng/mL; p:0.01), with a reduction ratio of 73 ± 14%. At baseline, direct and independent correlations were found between NGAL and, respectively, high‐sensitivity C‐reactive protein (β = 0.34; P = 0.03) and spKt/V (β = 0.35; P = 0.02). The findings showed that HD patients have chronically increased levels of circulating NGAL. However, with a single HD session, a marked reduction was achieved in circulating NGAL values, probably as a result of an important dialytic removal, similar to that observed for other cytokines. Finally, the direct independent correlation found between NGAL and spKt/V raises the question of whether, in the future, NGAL may also become a useful tool in predicting the adequacy of dialysis and in guiding the management of dialysis prescriptions.

Obestatin: A New Element for Mineral Metabolism and Inflammation in Patients on Hemodialysis

Background: Obestatin plays a key role in the process of energy balance maintenance with an anorectic effect. The main aim of the study was to evaluate obestatin in uremic patients to determine whether it is correlated with nutritional and inflammatory status. Methods: We studied plasma obestatin in uremic patients (n = 50) undergoing hemodialysis therapy and in healthy subjects. Plasma obestatin was measured using an ELISA kit. Results: Obestatin levels in uremic patients were lower than in healthy subjects (p < 0.0001). Patients with a body mass index (BMI) >23 had lower obestatin levels than those with a BMI <23 (p = 0.001). After multivariate analysis, direct correlations were maintained between obestatin and high-sensitivity C-reactive protein (β = 0.68, p < 0.0001) and total alkaline phosphatases (β = 0.30, p = 0.03), while inverse correlations were found with iron (β = –0.32, p = 0.002) and calcium-phosphorous product (β = –0.40, p = 0.001). Conclusions: Based on the present observational data, obestatin might be implicated in the inflammatory state and the disturbances of calcium/phosphate metabolism of hemodialysis patients. However, further studies are warranted to determine whether this hormone plays a key role in contributing to malnutrition and to the chronic inflammatory process.

Brain dysfunction in uremia: a question of cortical hyperexcitability?

OBJECTIVE To investigate whether patients with end-stage renal disease (ESRD) in different stages of the disease and undergoing different treatments display alterations in cortical excitability. METHOD A total of 36 patients with ESRD were evaluated at different stages of the disease and under different treatment by using standard transcranial magnetic stimulation (TMS) parameters. Moreover patients under haemodialysis underwent a double-blind crossover study (mannitol vs placebo) in order to better elucidate the pathophysiology of the acute effects of haemodialysis on cortical excitability. RESULTS Patients with ESRD in conservative therapy showed a significant reduction of short-interval intra-cortical inhibition (SICI). This alteration could be reversed by haemodialysis, peritoneal dialysis and by renal transplantation. After haemodialysis there was a significant increase of intra-cortical facilitation (ICF) inversely correlated with the drop in plasma osmolarity induced by the dialytic procedure. Mannitol infusion prevented the drop in plasma osmolarity and the haemodialysis-related changes in ICF. CONCLUSIONS ESRD patients showed alterations in cortical excitability that can be reversed by replacement therapies. We propose that the drop in plasma osmolarity is a key to the mechanism underlying post-haemodialysis cortical hyperexcitability. SIGNIFICANCE The results of this study give further insight to the pathophysiology of brain abnormalities in patients with chronic renal failure.