The importance of the blood levels of homocysteine, folate and vitamin B12 in patients with primary malignant brain tumors.

PURPOSE: Glioblastoma multiforme and anaplastic astrocytoma represent one of the most frequently occurring primary brain tumors with dismal survival rates. The aim of our study was to investigate whether values of homocysteine, folates and vitamin B12 can be prognostic markers in relapse diagnosis, treatment and monitoring of adult patients with malignant brain tumors. METHODS: Twenty-seven patients from the Neurosurgical Clinic, Clinical Center of Serbia with diagnosed malignant brain tumors (anaplastic astrocytoma GR III and glioblastoma multiforme GR IV), were included in the study. The patients were divided in two groups according to the progression of disease, 15 with and 12 without progression. RESULTS: Mean values of homocysteine were significantly higher in the group with progression compared to the group without malignant tumor progression, at the baseline point and after six months. Mean values of folate were similar across groups in all measurements, except in the 3rd month after surgery. Results regarding vitamin B12 were similar to folate, without any significance in group comparisons in the examined time points, as well as in vitamin B12 values change. CONCLUSIONS: Our results pointed out that total homocysteine in blood circulation appears to be a tumor marker for monitoring primary malignant brain tumor patients before and after surgery. The association of hyperhomocysteinemia with folate deficiency, also provides strong support for viewing hyperhomocysteinemia as a predictive marker for carcinogenesis. It is hoped that future research will continue to explore the clinical relevance of homocysteine as a tumor marker and a risk factor for astrocytoma and glioblastoma.

The effects of L-cysteine and N-acetyl-L-cysteine on homocysteine metabolism and haemostatic markers, and on cardiac and aortic histology in subchronically methionine-treated Wistar male rats.

Methionine is the precursor of homocysteine, a sulfur amino acid intermediate in the methylation and transsulfuration pathways; methionine-rich diets were used to induce hyperhomocysteinemia, and cardiovascular pathology was often observed. Other sulfur amino acids interfere with this metabolism, i.e., L-cysteine (Cys) and N-aceyl-L-cysteine (NAC), and probably also affect cardiovascular system. Their effects are controversial due to their ability to act both as anti- or pro-oxidant. Thus, this study aimed to elucidate their influence on levels of homocysteine, folate and vitamin B12, levels of different haemostatic parameters (fibrinogen, D-dimer, vWF Ag, vWF Ac) in rat serum or plasma as well as their effects on cardiac and aortic tissue histology in subchronically methionine-treated rats. Wistar albino rats were divided into 4 experimental groups: (a) control group (0.9% sodium chloride 0.1-0.2 mL/day) (n = 10) (K); (b) DL-methionine (0.8 mmol/kg/bw/day) (n = 10) (M); (c) DL-methionine (0.8 mmol/kg/bw/day) + L-cysteine (7 mg/kg/bw/day) (n = 8) (C); (d) DL-methionine (0.8 mmol/ kg/bw/day) + N-acetyl-L-cysteine (50 mg/kg/bw/day) (n = 8) (N). All substances were applied i.p., treatment duration 3 weeks. Lower levels of vitamin B12 in all the groups were found. Folate was reduced only in N group. Decreased fibrinogen was noted in C and N groups and increased D-dimer only in C. VWF activity was reduced in M and C groups. Deleterious effects in heart were observed, especially after Cys and NAC application. Aortic tissue remained unchanged. In conclusion, it could be said that sulfur amino acids have the significant impact on cardiovascular system in subchronically methionine-treated rats. This study points out the relevance of their complex interactions and deleterious effects mediated by either direct influence or procoagulant properties.

The Clinical Importance of Cystatin C and Hepatic Artery Resistive Index in Liver Cirrhosis.

BACKGROUND: Data suggest cystatin C (CysC) levels and hepatic artery resistive index (HARI) correspond to the progression of chronic liver disease. We aimed to evaluate the clinical significance of these parameters in assessment of fibrosis in patients with liver cirrhosis. METHODS: The cross-sectional study included 63 patients with liver cirrhosis. A control group consisted of 30 age- and gender-matched healthy persons. RESULTS: We confirmed significantly higher values of CysC in patients with cirrhosis compared to control group (p = 0.036). Average value of HARI in the examined group was increased (0.72 ± 0.06) and there was the statistically significant difference compared to controls (0.66 ± 0.03) (p < 0.001). We found statistically significant correlation between HARI and CysC in the study group. Analyzing the possibility of distinguishing healthy subjects from patients with fibrosis, we have found that the area under the curve is far greater in the HARI index than CysC. Comparison of CysC among Child⁻Pugh stages and correlation with a model for end-stage liver disease (MELD) score showed statistically significant results. CONCLUSION: We confirmed HARI is a more accurate parameter than CysC in discriminating healthy subjects from patients with fibrosis, while CysC could be a better indicator of the stage of liver cirrhosis.

Vitamin B complex mitigates cardiac dysfunction in high-methionine diet-induced hyperhomocysteinemia.

This research is designed to test the hypothesis that elevated homocysteine (Hcy) levels in vivo, caused by a deficit in vitamin B complex, promote changes in cardiac function and redox status that lead to heart failure. In order to conduct the study, we used adult male Wistar albino rats (n = 30; 4 weeks old; 100 ± 15 g body weight). Hyperhomocysteinaemia (HHcy) in these animals was achieved by dietary manipulation. For 4 weeks, the animals were fed with a standard rodent chow (control, CF), a diet enriched in methionine with no deficiency in B vitamins (i.e., folic acid, B6 and B12) (HMNV) or a diet enriched in methionine and deficient in B vitamins (HMLV). After 28 days of dietary manipulation, all animals were killed. The rat hearts were isolated and retrogradely perfused according to the Langendorff technique at a gradually increasing perfusion pressure. We found a negative correlation between elevated serum Hcy and total body and heart weight. The maximum rate of left ventricular pressure development was significantly increased in the HMNV group compared with in the other groups. Systolic left ventricular pressure was significantly changed in all groups. HHcy induces remodelling of the cardiac tissues, as moderate HHcy is associated with more prominent interstitial and perivascular fibrosis. Our results suggest that a high methionine diet without vitamin B complex causes profound negative effects associated with HHcy.

Role of cystatin C and renal resistive index in assessment of renal function in patients with liver cirrhosis.

AIM: To evaluate the clinical significance of cystatin C and renal resistive index for the determination of renal function in patients with liver cirrhosis. METHODS: We conducted a study of 63 patients with liver cirrhosis. A control group comprised of 30 age and gender-matched healthy persons. Serum cystatin C was determined in all study subjects and renal Doppler ultrasonography was made. Estimated glomerular filtration rate from serum creatinine (GFRCr) and cystatin C (GFRCys) was calculated. RESULTS: We confirmed significant differences in values of cystatin C between patients with different stages of liver cirrhosis according to Child-Pugh (P = 0.01), and a significant correlation with model of end stage liver disease (MELD) score (r s = 0.527, P < 0.001). More patients with decreased glomerular filtration rate were identified based on GFRCys than on GFRCr (P < 0.001). Significantly higher renal resistive index was noted in Child-Pugh C than in A (P < 0.001) and B stage (P = 0.001). Also, a significant correlation between renal resistive index and MELD score was observed (r s = 0.607, P < 0.001). Renal resistive index correlated significantly with cystatin C (r s = 0.283, P = 0.028) and showed a negative correlation with GFRCys (r s = -0.31, P = 0.016). CONCLUSION: Cystatin C may be a more reliable marker for assessment of liver insufficiency. Additionally, cystatin C and renal resistive index represent sensitive indicators of renal dysfunction in patients with liver cirrhosis.

Vascular endothelial growth factor in peritoneal dialysis patients.

BACKGROUND: Vascular endothelial growth factor (VEGF) is a glycoprotein which exerts mitogenic effects on endo thelial cells, enhances neoangiogenesis and microvascular permeability, influences leukocyte kinetics when upreg ulated by hypoxia and high-glucose concentration in experimental conditions and in human pathology. Peritoneal synthesis of VEGF has been demonstrated in patients on peritoneal dialysis (PD) treated with glucose-based dialy sate solutions. METHODS: The aim of the study was to determine the serum and peritoneal effluent VEGF concentrations in patients on chronic PD and to assess the relationship between age, gender, comorbidities, dialysis modality and vintage, therapy with erythropoiesis stimulating agents (ESA), angiotensin-converting enzyme inhibitors (ACEi) and statins and VEGF concentrations. Data on the use of ACEi, ESA, and statins were collected from patients' medical histories. VEGF was measured in serum and peritoneal effluent using the quantitative sandwich enzyme immunoassay (ELISA) kits (Quantikine® Human VEGF, R&D Systems, USA & Canada). Complete blood count and standard biochemical analyses (serum glucose, urea, creatinine, total protein, albumin, cholesterol, triglycerides, sodium, potassium, chloride, iron, total iron-binding capacity, ferritin, fibrinogen, C-reactive protein, and intact parathyroid hormone) were performed in fasting venous blood samples. Dialysis and residual components of Kt/V and normalized weekly creatinine clearance were calculated based on 24-hour urine and effluent collections. Peritoneal transport type was determined using the peritoneal equilibration test. RESULTS: Samples from 63 PD patients (39 males and 24 females, average age 61.97 ± 11.01 years) were analyzed. The average serum and effluent VEGF concentrations (231.84 ± 173.91 pg/mL and 38.39 ± 49.38 pg/mL, respectively) correlated significantly (p = 0.002). No significant difference was found in serum and effluent VEGF concentrations in relation to demographic characteristics, comorbidities, dialysis modality, therapy with ESA, ACEi, and statins. Patients treated with PD longer than 5 years had significantly higher serum VEGF levels (p < 0.05). Correlation analysis showed a statistically significant relationship between statin therapy and lower effluent VEGF concentration (p = 0.030). Serum VEGF concentration significantly correlated with fibrinogen serum concentration (p = 0.034) and glycemia (p = 0.004). Effluent VEGF concentration significantly correlated with cholesterolemia (p = 0.004). CONCLUSIONS: Serum VEGF concentrations were significantly higher in long term PD patients, and peritoneal effluent VEGF concentrations were significantly lower in patients receiving statins, suggesting a protective effect of those drugs on peritoneal membrane.

Plasma homocysteine levels in patients with liver cirrhosis.

BACKGROUND/AIM: Homocysteine (2-amino-4-mercaptobutyric acid) is an amino acid that may be found in small quantities in all cells, and is quantitatively the major methionine metabolite. The most prevalent form is protein-bound homocysteine (about 80%), mostly to albumins. If catabolism of homocysteine is impaired either due to enzyme defect or deficiency of required intracellular cofactors, homocysteine accumulates in cells and reaches the circulation. The aim of our study was to determine homocysteine values and factors affecting homocysteine metabolism in patients with liver cirrhosis. METHODS: The prospective study included 35 patients with liver cirrhosis and 30 age and sex matched healthy controls. All the examinations were based on: medical history, physical examination, laboratory tests including serum homocysteine levels and liver biopsy. The degree of liver failure was assessed according to the Child-Pugh classification. RESULTS: The mean plasma homocysteine levels were much higher in the patients with liver cirrhosis than in the healthy controls (t-test, p < 0.001). There was no significant difference between the plasma homocysteine concentration and etiology of liver cirrhosis (ANOVA, p > 0.05). Correlation analysis showed a positive correlation between the homocysteine and creatinine concentrations and between the serum albumin and homocysteine values, (Pearson's correlation, p < 0.01, and p < 0.05 respectively). CONCLUSION: In liver cirrhosis, the genesis of homocysteinemia is multifactorial, influenced significantly by impaired catabolic liver function, renal failure and hypoalbuminemia.

Risk factors for aortic valve calcification in patients on regular hemodialysis.

INTRODUCTION: Aortic valve calcification (AVC) accelerates development of aortic valve stenosis and cardiovascular complications. Hyperphosphatemia is one of the key risk factors for aortic valve calcification. AIM: The aim of this study was to evaluate the prevalence of AVC in patients on regular hemodialysis and to assess the impact of different factors on its appearance. METHOD: The study investigated a total of 115 patients treated in the Hemodialysis Department of the Urology and Nephrology Clinic at the Kragujevac Clinical Center in Serbia. The variables investigated were: serum albumin, C-reactive protein (CRP), homocysteine, total cholesterol, LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C), triglycerides (TG), Apolipoprotein A-I (Apo A-I), Apolipoprotein B (Apo B) and lipoprotein (a), calcium, phosphate and parathormone, and calcium-phosphorus product (Ca x P). Patients were evaluated by echocardiography for AVC. Statistical analysis included univariate and multivariate logistic regression analysis. RESULTS: Univariate regression analysis showed that serum phosphate levels and Ca x P are the most important risk factors for AVC (p<0.001). Multivariate logistic regression analysis revealed that hyperphosphatemia is an independent risk factor for AVC (p<0.001). CONCLUSION: Hyperphosphatemia is an independent risk factor for aortic valve calcification.

[Estrogen and ischemic heart disease in females].

INTRODUCTION: Although ischemic heart disease (IHD) develops in both genders under the influence of the same risk factors, it is much less frequent among female population, which is mostly assigned to favorable effects of estrogen. OBJECTIVE Since latest investigations have pointed to higher incidence of disease in female population, the objective of our study was to examine the relation between estrogen and other clinical and biochemical parameters significant for its manifestation. METHOD: The relation between estrogen levels and frequency of obesity, diabetes, hypertension as well as the levels of total, HDL, LDL i VLDL cholesterol, triglycerides, Lp(a), apoprotein A i B i PAl-1 was analyzed in 50 (25 pre- and postmenopausal) patients, treated due to IHD in the Health Center, Krusevac, in 2002 year. RESULTS: Low concentration of estrogen was found in 22 (44%) patients. In addition, frequency of diabetes, obesity and risky levels of high atherogenic lipid fractions (total and LDL cholesterol, Lp(a), apoprotein B) was insignificantly higher, whereas the concentrations of PAI 1, triglycerides and HDL cholesterol were lower, with significant correlation between estrogen level and PAI-1 (T = 0.32, p < 0.05). CONCLUSION: Despite all past investigations, numerous questions related to high incidence of IHD among premenopausal women, have remained open - whether it occurs as a consequence of reduced estrogen synthesis, lower expression of estrogen receptors, their modified function or maybe concomitant influence of other risk factors, not necessarily connected with sex, that eliminate protective effects of this hormone.

Troponin T levels in detection of perioperative myocardial infarction after coronary artery bypass surgery.

OBJECTIVES: The present study was designed to evaluate the clinical relevance of serum cardiac troponinT (cTnT) assay in detection of perioperative myocardial infarction (PMI) after coronary artery bypass grafting (CABG). MATERIALS AND METHODS: The clinical utility of cTnT was compared to that of total CK, CKMB mass, CKMB activity and myoglobin. Serial venous blood samples were obtained before surgery and 4, 8, 16, 24, 48 and 72 hours after aortic unclamping (AU) in 42 patients who underwent CABG. We had 6 PMI patients, 24 patients with minor myocardial damage (MMD) and 12 without ischemic myocardial changes (no IMC). RESULTS: In discriminating no IMC from PMI the diagnostic sensitivity, specificity and the predictive values of cTnT were superior to that of CKMB mass, CKMB activity, myoglobin and total CK during 72 hours after AU. In discriminating MMD from PMI the diagnostic performance for CKMB mass and CKMB activity was superior to that of cTnT during the first 24 hours. After 24 hours the diagnostic performance for cTnT was improved but began to decline for CKMB isoenzymes. The discriminatory power of myoglobin measurements was lower than that of cTnT and CKMB mass. CONCLUSION: Our results indicate that troponin T is an accurate marker for the detection and monitoring of perioperative myocardial damage, especially 24 hours after AU.