Biomarkers of Glyco-Metabolic Control in Hemodialysis Patients: Glycated Hemoglobin vs. Glycated Albumin.

Background and Objectives: Glycated hemoglobin (HbA1c) dosage is considered the gold standard in glycol-metabolic monitoring, but it presents limits, which can underestimate the glycemia trend. In this regard, it was introduced the glycated albumin (GA). The aim of the study is to verify the predictivity of the GA compared to HbA1c in identifying glyco-metabolic alterations in non-diabetic and diabetic hemodialysis (HD) patients. Materials and Methods: For this purpose, we conducted a multicenter study involving one analysis laboratory and six dialysis centers in the Lazio region (Rome, Italy). Both diabetic and non-diabetic HD patients represent the study population, and the protocol included five time points. Results: The analyzed data highlighted the ability of GA to predict changes in glycemic metabolism in HD patients, and GA values are not significantly influenced, like HbA1c, by dialysis therapy itself and by comorbidities of the uremic state, such as normochromic and normocytic anemia. Thus, GA seems to reflect early glyco-metabolic alterations, both in patients with a previous diagnosis of diabetes and in subjects without diabetes mellitus. As part of this study, we analyzed two HD patients (one diabetic and one non-diabetic) in which GA was more predictive of glycol-metabolic alterations compared to HbA1c. Our study confirms the need to compare classical biomarkers used for the monitoring of glyco-metabolic alterations with new ones, likely more reliable and effective in specific subgroups of patients in which the classic biomarkers can be influenced by the preexisting pathological conditions. Conclusions: In conclusion, our evidence highlights that in uremic patients, GA shows a better ability to predict glyco-metabolic alterations allowing both an earlier diagnosis of DM and a prompt modulation of the hypoglycemic therapy, thus improving the clinical management of these patients.

Influence of dialysis techniques and alternate vitamin supplementation on homocysteine levels in patients with known MTHFR genotypes.

BACKGROUND: Treatment with folic acid and vitamin B12 appears capable of reducing total plasma homocysteine levels (tHcy), but it is unknown whether vitamin B12 alone reduces tHcy values. In this study we investigate the effects of alternate vitamins supplementation on homocysteine levels in patients treated by diffusive and convective dialysis techniques. METHODS: 74 patients were randomized blindly into two groups of 37 subjects each. The first group was treated initially with vitamin B12 for 2 months and with folic acid for the following 2 months. The second group was treated initially with folic acid. A wash out period of 2 months followed the treatment in both groups. RESULTS: Total homocysteine levels decreased in both groups following the alternate vitamins therapy and dialysis, without significant difference between diffusive and convective techniques. Surprisingly, after the wash-out period, tHcy increased remarkably, regardless of the dialysis procedure used. At the end of the study, folate levels showed a higher reduction with haemodialysis compared to haemodiafiltration. In contrast, vitamin B12 levels showed a significant increase using diffusive haemodialysis, confirming a decisive role of membrane performance. CONCLUSIONS: In conclusion we show for the first time that, even if total homocysteine levels decreased in both dialysis procedures, the convective techniques demonstrate a superior capacity on the reduction of tHcy levels compared to the diffusive method. Moreover, the lower depletion of vitamin B12 by diffusive techniques could determine a higher reduction of folate levels, demonstrating the decisive role of the membrane performance in the treatment of this patients.

Performances of capillary electrophoresis and HPLC methods in HbA1c determination: diagnostic accuracy in HbS and HbD-Iran variants' presence.

BACKGROUND: Glycated hemoglobin (HbA1c) provides a useful estimate of mean glycemia in patients with diabetes and is directly related to risks for diabetes complications. The aim of this study is to compare a capillary electrophoresis method and two high-performance liquid chromatography (HPLC) cation-exchange analyzers (Variant II (Bio-Rad Laboratories, Inc., Hercules, CA) and G8 (Tosoh Biosciences, San Francisco, CA)) to identify the most reliable method in Hb variants' presence. METHODS: Measurements of HbA1c were carried out in blood samples from 200 Tor Vergata Hospital patients, using G8 Tosoh, and from 107 San Filippo Neri Hospital patients, using Variant II Bio-Rad methods. All samples were analyzed by Capillarys 2 Flex Piercing (FP; Sebia, Lisses, France). RESULTS: There was a good concordance between the results of capillary electrophoresis and HPLC methods (R(2) = 0.99, P < 0.0001 for G8 HPLC; R(2) = 0.99, P < 0.0001 for Variant II HPLC). During the study, we observed that some Hb variants, HbS and HbD-Iran, can alter the HbA1c level. CONCLUSIONS: Since the HbA1c test is now recommended for diagnosing diabetes, and minimal variation of the concentration affects the clinical therapy, it is very important that the results are reliable and interference-free. Capillarys 2-FP analyzer is suitable for this purpose and sometimes it showed some advantages with respect to the HPLC analyzers tested, especially when Hb variants are present.

Plasma and erythrocyte membrane phospholipids and fatty acids in Italian general population and hemodialysis patients.

BACKGROUND: Dyslipidemia and abnormal phospholipid metabolism are frequent in uremic patients and increase their risk of cardiovascular disease (CVD): ω-3 polyunsaturated fatty acids (PUFAs) may reduce this risk in the general population. In this study we compared the plasma and erythrocyte cell membrane composition of PUFAs in a group of Caucasian hemodialysis (HD) patients and in a control group of healthy subjects and evaluated the erythrocyte/cell membrane fatty acid ratio as a marker of the dietary intake of phospholipids. The relationship between ω-3 and ω-6 fatty acids and the possible differences in PUFAs concentrations were also investigated. METHODS AND RESULTS: After obtaining a fully informed consent, a total of ninety-nine HD patients and 160 non uremic control subjects from "Tor Vergata" University Hospital were enrolled into the study. None of them took antioxidant drugs or dietary supplements for at least 90 days prior to the observation. Blood samples were analysed by gas-chromatographic coupled to a mass spectrometric detector.The daily intake of total calories, proteins, lipids and carbohydrates is significantly lower in HD patients than in controls (p < 0.001). Most plasma and erythrocyte PUFA were also reduced significantly in HD patients (p < 0.001). CONCLUSIONS: Our results suggest that many classes of PUFAs are lacking in HD patients, due to the removal of nutrients during the dialysis and to persistent malnutrition. A dietary treatment addressed to increase plasma ω-3 PUFAs and to optimize ω-6/ω-3 ratio may exert a protective action and reduce the risk of CVD in HD patient.

Erythrocyte glutathione transferase: a potential new biomarker in chronic kidney diseases which correlates with plasma homocysteine.

The erythrocyte glutathione S-transferase (e-GST) is a member of a superfamily of inducible enzymes involved in cell detoxification that shows an increased expression in chronic kidney disease (CKD) patients. We propose a new automated analysis procedure for e-GST activity that has been validated in 72 CKD patients and 62 maintenance hemodialysis patients (MHD). Regression analysis was carried out to assess association between e-GST activity data, main clinical variables, and plasma homocysteine (Hcy), a modified sulfur amino acid known as potential risk factor for cardiovascular disease that is increased above normal levels in more than 90% of the uremic patients. An increased e-GST activity was confirmed in MHD patients (N=62; 10.2±0.4 U/gHb) compared with healthy subjects (N=80; 5.8±0.4 U/gHb), and as an original finding, a significant increase of e-GST activity was observed in pre-dialysis CKD patients with a positive correlation with disease severity weighted according to the four stages of "Kidney Disease Outcomes Quality Initiative" classification (7.4±0.5, 8±1, 9.5±0.6, 12±1 U/gHb, respectively). No correlation was found between e-GST activity and hemoglobin, transferrin, blood iron and the markers of systemic inflammation and renal function such as alpha-1 acid glycoprotein and high-sensitive C-Reactive Protein, beta-2 microglobulin and the index of malnutrition-inflammation PINI, while a significant correlation was observed for the first time between plasma Hcy and e-GST activity (r2=0.64, P<0.0001) in MHD patients. Hcy, however, was not identified as an inhibitor of e-GST enzyme. The results in this study suggest the potential for automated e-GST analysis as a valuable tool to further explore phase II-related uremic toxicity in CKD and MHD patients.

Multiple Sclerosis: kFLC index values related to gender.

BACKGROUND: Multiple sclerosis (MS) is a chronic multifactorial inflammatory and neurodegenerative disease of the central nervous system (CNS). The identification of biomarkers with good diagnostic and prognostic power is of great importance for monitoring and treating MS patients. METHODS: We analyzed serum and cerebrospinal fluid of 228 patients, with different neurological disorders and with MS to confirm our previous results and determine a possible gender difference of kFLC Index cut-off. RESULTS: We have obtained a kFLC Index cut-off of 12.5 (100% specificity and 90.4% sensitivity) and 11 (100% specificity and 97.5% sensitivity) for women and men with MS respectively. CONCLUSIONS: This study reinforces the importance that kFLC Index could have as a diagnostic aid to detect MS. Our data highlight a difference in the cut-off of the kFLC Index calculated by gender; male patients with a kFLC Index value greater than 11 are at higher risk to develop MS respect females having the same result.

Can Serum Cystatin C predict long-term survival in cardiac surgery patients?

Renal dysfunction is a risk factor for morbidity and mortality in cardiac surgery patients. Serum Cystatin C (sCysC) is a well-recognized marker of early renal dysfunction but few reports evaluate its prognostic cardio-vascular role. The aim of the study is to consider the prognostic value of sCysC for cardiovascular mortality. Four hundred twenty-four cardiac-surgery patients (264 men and 160 women) were enrolled. At admission, all patients were tested for renal function and inflammatory status. Patients were subdivided in subgroups according to the values of the following variables: sCysC, serum Creatinine (sCrea), age, high sensitivity-C Reactive Protein, fibrinogen, surgical procedures and Kaplan-Meier cumulative survival curves were plotted. The primary end-point was cardiovascular mortality. In order to evaluate the simultaneous independent impact of all measured variables on survival we fitted a multivariate Cox-Proportional Hazard Model (CPHM). In Kaplan-Meier analysis 124 patients (29.4%) reached the end-point. In multivariate CPHM, the only significant predictors of mortality were sCysC (p<0.00001, risk ratio: 1.529, CI: 1.29-1.80) and age (p=0.039, risk ratio: 1.019, CI: 1.001-1.037). When replacing sCysC with sCrea, the only significant predictor of mortality was sCrea (p=0.0026; risk ratio 1.20; CI: 1.06-1.36). Increased levels of sCysC can be considered a useful biomarker of cardiovascular mortality in cardiac-surgery patients.

Delayed diagnosis of coeliac disease increases cancer risk.

BACKGROUND: The association between coeliac disease (CD) and neoplasms has been long established, but few data are available about the risk factors. The aim of this paper is to estimate the risk of developing a neoplasm among non diagnosed coeliac patients and to evaluate if this risk correlates with the age of patients at diagnosis of coeliac disease. METHODS: The study population consists of patients (n = 1968) diagnosed with CD at 20 Italian gastroenterology referral Centers between 1st January 1982 and 31st March 2005. RESULTS: The SIR for all cancers resulted to be 1.3; 95% CI = 1.0-1.7 p < 0.001. The specific SIRs for non Hodgkin lymphoma was 4.7; 95% CI = 2.9-7.3 p < 0.001, for the small bowel carcinoma 25; 95% CI = 8.5-51.4 p < 0.001, for non Hodgkin lymphoma 10; 95% CI = 2.7-25 p = 0.01, finally for the stomach carcinoma 3; 95% CI = 1.3-4.9 p < 0.08. The mean age at diagnosis of CD of patients that developed sooner or later a neoplasm was 47,6 +/- 10.2 years versus 28.6 +/- 18.2 years of patients who did not. CONCLUSION: Coeliac patients have an increased risk of developing cancer in relation to the age of diagnosis of CD. This risk results higher for malignancies of the gastro-intestinal sites. An accurate screening for tumors should be performed in patients diagnosed with CD in adulthood and in advancing age.

Cardiac calcifications: Fetuin-A and other risk factors in hemodialysis patients.

Cardiac calcifications are a frequent finding in hemodialysis for chronic renal failure. Several factors may play a role in the intimal and medial calcification of coronary arteries such as age and some known atherogenetic factors. In addition, Fetuin-A has been proposed as a protective agent through solubilization of calcium phosphate salt. Fetuin-A is also a marker of inflammatory-nutritional state, and its changes could be an expression of this condition. The aim of this cross-sectional study is to evaluate the relative importance of risk factors of calcifications with special regard to Fetuin-A. The study was conducted with 132 hemodialysis patients. They were subjected to multislice computed tomography for evaluation of calcium deposits in the heart. In addition, the patients were sampled for evaluation of calcium-phosphate parameters, lipid profile, nutritional and inflammatory markers, and also Fetuin-A. There was a wide variability of the extent of calcium deposits expressed as Agatston score, with only 9.3% of patients without calcifications. Age, hemodialysis age, sex, calcium-phosphate parameters, and lipid profile were important risk factors, together with nutritional and inflammatory status of the patients. An inverse correlation between coronary calcium score and Fetuin-A emerged from a multiple regression analysis. However, there was no significant difference in serum Fetuin-A among different grades of calcium score. By dividing the patients in tertiles of serum Fetuin-A, an association between low levels of Fetuin-A and high calcification score was found. Fetuin-A as dependent variable was strictly linked to prealbumin serum levels. In addition, there was a clear link between cardiac calcification scores and inflammatory-nutritional markers. Serum calcium and treatment with calcitriol emerged as predictive variables of coronary score.Fetuin-A could be involved in the process of calcification both in the case of markedly low serum levels, due to decreased prevention of calcium phosphate precipitation, and also as a marker of inflammation, a well-known risk factor of atherogenesis. Treatment with intravenous calcitriol could marginally enhance cardiac calcifications, probably through its hypercalcemic effect.

Homocysteine, cysteine, folate and vitamin B12 status in type 2 diabetic patients with chronic kidney disease.

BACKGROUND: Hyperhomocysteinemia (hHcy) is a risk factor in the progression of chronic kidney disease (CKD). In type 2 diabetes (T2D), hHcy is strongly associated with increased risk of cardiovascular disease. Vitamin B12 and folic acid supplementation have been reported to lower homocysteine (tHcy) levels, but no data on plasma tHcy, cysteine (Cys), folate and vitamin B12 levels in T2D-CKD patients are reported. PROCEDURES: tHcy and Cys levels were analyzed in 178 T2D-CKD patients by high performance liquid chromatography (HPLC) with fluorescence detection. In addition, we determined folate and vitamin B12 levels using a chemiluminescence method. RESULTS: tHcy and Cys levels were increased in T2D patients, and this rise positively correlated with the CKD stage (P < 0.001). Folate levels were comparable to controls at various CKD stages, whereas vitamin B12 levels were lower, except at stage IV. We did not find any correlation between B-vitamins and levels of tHcy and Cys, regardless of the CKD stage. CONCLUSIONS: This is the first study reporting tHcy, Cys and B-vitamins status in T2D-CKD patients. Although limited to our cohort of 178 patients, our findings could be helpful in clarifying the conflicting literature regarding B-vitamins supplementation. Further studies are necessary before any Hcy-lowering therapy can be safely established in T2D-CKD subjects.

Erythrocyte glutathione transferase activity: a possible early biomarker for blood toxicity in uremic diabetic patients.

Erythrocyte glutathione transferase (e-GST) displays increased activity in patients with renal damage and positive correlation with homocysteine (Hcy) in patients under maintenance hemodialysis. Here, we determined e-GST, Hcy, and erythrocyte catalase (e-CAT) in 328 patients affected by type 2 diabetes mellitus (T2DM), 61 diabetic non-nephropathic patients and 267 affected by diabetes and by chronic kidney disease (CKD) under conservative therapy subdivided into four stages according to K-DOQI lines. e-GST activity was significantly higher in all T2DM patients compared to the control group (7.90 ± 0.26 vs. 5.6 ± 0.4 U/g(Hb)), and we observed an enhanced activity in all subgroups of CKD diabetic patients. No significant correlation or increase has been found for e-CAT in all patients tested. Mean Hcy in diabetic patients is higher than that in healthy subjects (33.42 ± 1.23 vs. 13.6 ± 0.8 µM), and Hcy increases in relation to the CKD stage. As expected, a significant correlation was found between e-GST and Hcy levels. These findings suggest that e-GST hyperactivity is not caused directly by diabetes but by its consequent renal damage. e-GST, as well as Hcy, may represent an early biomarker of renal failure.

Determination of κFLC and κ Index in cerebrospinal fluid: a valid alternative to assess intrathecal immunoglobulin synthesis.

Intrathecal immunoglobulin synthesis is observed in several disorders of the central nervous system, but its detection by current laboratory tests is relatively insensitive and operator depending. We assessed the diagnostic accuracy of a nephelometric assay for k free light chain determination in cerebrospinal fluid and serum. The patients were grouped according to clinical and laboratory criteria. ROC curves for all methods were performed to find the best cut-off value. kFLC Index seems to be more accurate than other parameters. Our data indicate that nephelometric assay for kFLCs in CSF reliably detect intrathecal immunoglobulin synthesis and discriminate multiple sclerosis patients.

Atherosclerosis, dyslipidemia, and inflammation: the significant role of polyunsaturated Fatty acids.

Phospholipids play an essential role in cell membrane structure and function. The length and number of double bonds of fatty acids in membrane phospholipids are main determinants of fluidity, transport systems, activity of membrane-bound enzymes, and susceptibility to lipid peroxidation. The fatty acid profile of serum lipids, especially the phospholipids, reflects the fatty acid composition of cell membranes. Moreover, long-chain n-3 polyunsatured fatty acids decrease very-low-density lipoprotein assembly and secretion reducing triacylglycerol production. N-6 and n-3 polyunsatured fatty acids are the precursors of signalling molecules, termed "eicosanoids," which play an important role in the regulation of inflammation. Eicosanoids derived from n-6 polyunsatured fatty acids have proinflammatory actions, while eicosanoids derived from n-3 polyunsatured fatty acids have anti-inflammatory ones. Previous studies showed that inflammation contributes to both the onset and progression of atherosclerosis: actually, atherosclerosis is predominantly a chronic low-grade inflammatory disease of the vessel wall. Several studies suggested the relationship between long-chain n-3 polyunsaturated fatty acids and inflammation, showing that fatty acids may decrease endothelial activation and affect eicosanoid metabolism.

Chronic treatment with statins increases the availability of selenium in the antioxidant defence systems of hemodialysis patients.

PROJECT: Oxidative stress (OS) is enhanced in hemodialysis (HD) patients. Lipid peroxidation and oxidative damage to glycids, proteins and nucleic acids are the main consequences of OS and are associated with increased cardiovascular risk. Vitamin E and glutathione peroxidase (GSH-Px) represent the main antioxidant systems in human cells. Selenium (Se), bound to the active sites of GSH-Pxs, plays a critical role in this antioxidant defence system. Statins are widely used and extensively investigated in the prevention of cardiovascular disease, notably in high-risk subjects. Several studies show antioxidant effects of statins not related to their lipid-lowering action. Our study aimed to compare serum Se concentration in ESRD patients on maintenance HD and in homogeneous healthy subjects and to investigate whether chronic treatment with statins may interfere with serum Se concentration in HD patients. PROCEDURE: A total of 103 HD patients and 69 healthy subjects were enrolled; HD patients were divided into patients who were not treated with statins (group A) and patients who assumed statins since 6 months at least (group B). Serum Se was determined by atomic absorption spectrometry. RESULTS: Serum Se was significantly lower in HD patients of group A compared with healthy subjects (81.65+/-19.66 Vs. 96.47+/-15.62 mcg/L, p<0.0040). However, in HD patients who assumed statins serum, Se was significantly higher than in HD patients who did not (111.83+/-18.82 vs. 81.65+/-19.66 mcg/L, p<0.0001). CONCLUSIONS: Our results suggest that in HD patients chronic treatment with statins is related to higher-serum Se concentration.

Effect of a gluten-free diet on the risk of enteropathy-associated T-cell lymphoma in celiac disease.

Patients with celiac disease have an increased rate of enteropathy-associated T-cell lymphoma, but conflicting data are available about the protective role of a gluten-free diet with regard to the development of this malignancy. We followed 1,757 celiac patients for a total period of 31,801 person-years, collecting data about the frequency of gluten intake and the incidence of the enteropathy-associated T-cell lymphoma. Out of the nine celiac patients who developed an intestinal lymphoma [standard morbidity ratio of 6.42 (95% CI = 2.9-12.2; P < 0.001)], only two kept a strict gluten-free diet after the diagnosis of celiac disease and developed the malignancy after the peridiagnosis period of 3 years, dropping therefore the standard morbidity ratio to 0.22 (95%CI = 0.02-0.88; P < 0.001). The risk of developing an intestinal lymphoma for the celiac patients that used to have dietary gluten was significant (X(2 )= 4.8 P = 0.01). These results show that a strict gluten-free diet is protective towards the development of enteropathy-associated T-cell lymphoma.

In vitro tests indicate that certain varieties of oats may be harmful to patients with coeliac disease.

BACKGROUND: The presence of oats in gluten-free diet is controversial. The aim of this work is to evaluate if different varieties of oats exert different toxicity in coeliac disease. METHODS: Three varieties of oats were tested by two in vitro assay based on the known ability of peptic-tryptic digests of coeliac-active proteins to agglutinate K562 cells and to disrupt lysosomes, respectively. RESULTS: Avenins from the Italian variety Astra and the Australian variety Mortlook were much more active than the Australian variety Lampton. Gliadin, digested in the same way, certainly displayed more activity than all three avenins, but rice (var. Roma) did not have measurable activity. CONCLUSIONS: The results indicate that some varieties of oats may be potentially harmful to individuals with coeliac disease and therefore should be excluded from the gluten-free diet required to maintain good health in coeliac disease. It is important to realize that constant, small amounts of active proteins in the diet, such as certain avenins, may prevent complete recovery of the intestinal mucosa in this disease.