Jan Kvasnicka

Insulin action and fibrinolysis influenced by vitamin E in obese Type 2 diabetes mellitus

Increased oxidative stress, hypofibrinolysis and insulin resistance are present in obese Type 2 diabetic patients. It is supposed that treatment with antioxidant alpha-tocopherol (vitamin E) could not only decrease free radical production, but also ameliorate insulin action. We evaluated the effect of 3 months administration of vitamin E (600 mg daily) on insulin action examined by hyperinsulinemic clamp in 11 obese Type 2 diabetic patients. Oxidative stress and fibrinolysis were also determined. The administration of vitamin E caused a decrease of glucose disposal rate (26.6 +/- 9.5 vs 21.3 +/- 7.5 micromol/kg/min, P < 0.02) and of metabolic clearance rate of glucose (3.7 +/- 1.6 vs 2.9 +/- 0.8 ml/kg/min. P < 0.02). A decrease of insulin receptor number was observed on erythrocytes after vitamin E (284 +/- 84 vs 171 +/- 59 pmol/l, P < 0.01). Significantly higher plasma malondialdehyde (MDA) concentration documented an increased oxidative stress in diabetic patients as compared with healthy persons (3.13 +/- 0.68 vs 1.89 +/- 0.18 micromol/l, P<0.001). An inverse relationship was found between MDA concentration and insulin sensitivity expressed by glucose disposal rate (r = -0.73). Vitamin E further worsened the hypofibrinolysis documented by a decrease of tissue plasminogen activator (P < 0.01) without changes in its inhibitor PAI-1. In conclusion. our results demonstrate that higher doses of vitamin E may further deteriorate insulin action and fibrinolysis in obese Type 2 diabetic patients.

Increase of adhesion molecules, fibrinogen, type‐1 plasminogen activator inhibitor and orosomucoid in growth hormone (GH) deficient adults and their modulation by recombinant human GH replacement

GH deficiency (GHD) is usually associated with a higher incidence of cardiovascular disease (CVD). The aim of this study was to establish whether patients with GHD, like those with CVD, show an increase in fibrinogen (FBG), type‐1 plasminogen activator inhibitor (PAI‐1), acute phase response proteins (APR), and soluble adhesion molecules. The effect of recombinant human GH (rhGH) replacement, on these parameters was also investigated.

Relationship of oxidative stress and fibrinolysis in diabetes mellitus

This study attempted to verify the existence of a relationship between oxidative stress documented by malondialdehyde (MDA) and superoxide dismutase (SOD) and fibrinolysis analysed by tissue plasminogen activator (tPA) and its inhibitor (PAI‐1) in diabetes mellitus. Forty‐seven patients with Type 1 (n = 27) and Type 2 (n = 20) diabetes were examined together with 20 non‐diabetic controls. The following were analysed: plasma MDA concentration, SOD activity in erythrocytes, tPA activity and antigen, PAI‐1 activity and antigen, fasting blood glucose, fructosamine, glycated haemoglobin (HbAlc), and urine albumin. SOD activity was decreased in patients with diabetes. This contrasted with an increased plasma MDA concentration especially in Type 2 diabetes as compared with Type 1 or healthy persons (p < 0.001). tPA activity was increased in both groups of patients with diabetes as compared to healthy persons (p < 0.001), PAI‐1 activity was higher in Type 2 diabetes with vascular changes than in the remaining subgroups (p < 0.001). Multivariate analysis revealed a significant positive relationship between plasma MDA concentrations and PAI‐1 antigen (r = 0.53, p < 0.001) and a negative relationship between SOD and tPA activities (r = −0.53, p < 0.01). We conclude that oxidative stress may modulate fibrinolytic properties in diabetes mellitus.

Comparison of laser-Doppler flowmetry with biochemical indicators of endothelial dysfunction related to early microangiopathy in Type 1 diabetic patients

The aim of this study was to compare biochemical markers of endothelial activation with microcirculation measured by laser-Doppler flowmetry in Type 1 diabetic patients with or without microangiopathy. A total of 44 Type 1 diabetic patients were subdivided into those with (n=24) and without (n=20) microangiopathy according to ophthalmological findings and the presence or absence of microalbuminuria. The control group consisted of 25 healthy people of comparable age, sex, and body mass index. Postocclusive reactive hyperemia (PORH) and thermal hyperemia (TH, at 44 degrees C) were measured at the forearm. Serum N-acetyl-beta-glucosaminidase (NAG) activity, serum E-selectin, and ICAM-1 concentrations were used as biochemical markers of endothelial dysfunction. A significantly lower velocity of perfusion increase during postocclusive hyperemia (PORH(max) x t(1)(-1)) and during thermal hyperemia (TH(max) x t(2)(-1)) (P<.01) were accompanied by higher serum NAG activity (20.9+/-4.6 vs. 16.3+/-2.5 U l(-1), P<.01) in diabetic patients with microangiopathy as compared to healthy persons. An inverse relationship was found between PORH(max) x t(1)(-1) and NAG (r=-.33) results in diabetic patients. In addition, higher mean values of serum NAG activity, E-selectin, and ICAM-1 concentrations were associated with significantly lower values of microcirculation parameters (PORH(max) x t(2)(-1) and TH(max) x t(2)(-1)) in six patients without microangiopathy who had at least one of the above biochemical markers higher than mean+2 S.D. range. We suggest that serum NAG activity, E-selectin, and ICAM-1 concentrations may be used together with laser-Doppler flowmetry in Type 1 diabetic patients as early indicators of vascular changes in very early stage of diabetic microangiopathy.

Platelet glycoprotein GP VI 13254C allele is an independent risk factor of premature myocardial infarction

AIM The purpose of this study was to asses the impact of haemostatic and platelet receptor gene polymorphisms as an inherited risk factor for premature onset of myocardial infarction (MI). METHODS Polymorphisms of platelet receptors - GP Ia (807C>T, rs1126643), GP VI (13254T>C, rs1613662), GP IIIa (HPA-1, rs5918), PAR -1 (IVS -14A>T; rs168753), P2Y(12) (34C>T, rs6785930 and H1/H2 haplotype, rs2046934), and genetic variations of the gene coding for cyclooxygenase-1 (COX-1) ( -842A>G, rs10306114 and 50C>T, rs3842787) were investigated. Mutations in the genes coding for coagulation factor V (Q506R (Leiden) mutation, rs6025) and factor II (prothrombin G20210A, rs1799963) were also determined. The prevalence of gene polymorphisms was investigated in 105 consecutive patients with premature MI. This was compared with the same gene polymorphism prevalence in a group of 132 patients in which coronary artery disease had been excluded. Genotyping was done using PCR, followed by melting curve analysis with specific fluorescent hybridization probes. RESULTS A significant association between GP VI 13254C allele carriers and premature MI was found (p=0.025). No other differences in prevalence of the investigated polymorphisms between the compared patient populations reached statistical significance. In a logistic regression, which took other cardiovascular risk factors into account, the significance of the GP VI 13254C allele and vascular risk was suggested (OR 1.888, 95% C.I. 1.029 to 3.464, p=0.040). In a binary logistic regression the positive relationship between the GP VI genotype and female gender was observed (0R 3.676; 95% C.I. 1.159 to 11.628; p=0.027). The frequencies of GP VI and GP Ia gene polymorphisms were independent of one another (p=0.836). CONCLUSION The presence of the GP VI 13254C allele is an independent predictor of premature MI.

Elevated Inflammation Markers in Pheochromocytoma Compared to Other Forms of Hypertension

Objective: To investigate the effect of long-term catecholamine excess in pheochromocytoma on leukocyte and platelet count and on proteins of acute-phase response. Methods: Fifteen subjects with pheochromocytoma, 16 with primary aldosteronism, 18 with essential hypertension and 17 healthy controls were studied. Sixteen subjects with pheochromocytoma were investigated after tumor removal. Leukocyte, neutrophil and platelet count, as well as C-reactive protein were measured in all subjects, while fibrinogen, α1-antitrypsin, α2-macroglobulin, orosomucoid, transferrin and prealbumin were only measured in subjects with pheochromocytoma, primary aldosteronism and essential hypertension. Results: Subjects with pheochromocytoma showed significantly higher leukocyte [7.5 ± 0.9 109/l, p < 0.001 vs. primary aldosteronism (5.4 ± 0.9 109/l) and healthy controls (5 ± 0.9 109/l), p = 0.04 vs. essential hypertension (6.3 ± 1.6 109/l)], neutrophil (p < 0.001 vs. primary aldosteronism and healthy subjects) and platelet counts (p < 0.001 vs. primary aldosteronism; p = 0.01 vs. essential hypertension) compared to the other groups of subjects. Similar results were obtained for positive proteins of acute-phase response in subjects with pheochromocytoma [C-reactive protein: 0.62 ± 0.52 mg/dl, p < 0.001 vs. healthy subjects (0.08 ± 0.08 mg/dl), p = 0.001 vs. primary aldosteronism (0.17 ± 0.19 mg/dl), p = 0.04 vs. essential hypertension (0.31 ± 0.26 mg/dl); fibrinogen: p = 0.02 vs. primary aldosteronism; orosomucoid: p = 0.005 vs. primary aldosteronism; α2-macroglobulin: p = 0.009 vs. primary aldosteronism]. No significant differences were found in plasma levels of α1-antitrypsin, transferrin and prealbumin. Tumor removal led to a significant decrease in leukocyte (p = 0.004), neutrophil (p = 0.007) and platelet count (p = 0.003) and also to a significant decrease in acute-phase proteins (C-reactive protein: p = 0.03, fibrinogen: p = 0.008, α1-antitrypsin: p = 0.003, orosomucoid: p = 0.04). Conclusions: Chronic catecholamine excess in pheochromocytoma is accompanied by an increase in inflammation markers which was reversed by the tumor removal.

Platelet gene polymorphisms and risk of bleeding in patients undergoing elective coronary angiography: A genetic substudy of the PRAGUE-8 trial

AIM Utilization of cardiac catheterization has increased dramatically over time. Bleeding is a major prognostic predictor after percutaneous coronary catheterization procedures. This study aimed to assess the impact of eight polymorphisms of genes encoding platelet receptors and enzymes on the risk of bleeding in patients undergoing elective coronary angiography (CAG). METHODS Polymorphisms of platelet receptors, GP Ia (807C>T, rs1126643), GP VI (13254T>C, rs1613662), GP IIIa (HPA-1, rs5918), PAR-1 (IVS-14A>T, rs168753), P2Y(12) (34C>T, rs6785930 and H1/H2 haplotype, rs2046934), and genetic variations of the gene coding for cyclooxygenase-1 (COX-1) (-842A>G, rs10306114 and 50C>T, rs3842787) were studied. The frequencies of gene polymorphisms carriers were investigated in 696 patients undergoing elective CAG because of suspected or proven stable coronary artery disease. Genotyping was done using PCR, followed by melting curve analysis with specific fluorescent hybridization probes. RESULTS In patients undergoing elective CAG (without ad hoc percutaneous coronary intervention (PCI) and without clopidogrel pretreatment) a significant association was found between bleeding risk and variations in the gene coding for COX-1 (-842A>G and 50C>T) (both p=0.013). Six other investigated polymorphisms did not show any influence on bleeding complications. After controlling for potential bleeding confounders, the association between COX-1 gene polymorphisms (-842A>G and 50C>T) and bleeding risk remained statistically significant (both odds ratios 12.1, p=0.012). CONCLUSION Cyclooxygenase-1 -842G and 50T alleles significantly contribute to the risk of bleeding complications in patients undergoing elective CAG. Genetic testing is able to influence the safety of diagnostic cardiac catheterization in large numbers of low risk patients with borderline indications.

Changes in markers of anemia and iron metabolism and how they are influenced by antianemics in postpartum period

Background. The object of this study was to examine the occurrence of iron deficiency anemia in women after spontaneous delivery, changes in clinical and laboratory indicators of anemia in postpartum period and their possible control by administration of peroral antianemics.

Plasma free N-terminal fibronectin 30-kDa domain as a marker of endothelial dysfunction in type 1 diabetes mellitus.

The plasma free N‐terminal fibronectin 30‐kDa domain was measured in 44 type 1 diabetic patients and in 20 healthy subjects. A significantly raised mean concentration of a free N‐terminal fibronectin 30‐kDa domain was found in plasma of diabetic patients with proliferative retinopathy as compared with healthy persons (P < 0·001). A positive correlation was observed between free N‐terminal fibronectin 30‐kDa domain and von Willebrand factor in plasma of all examined subjects (r = 0·62, P < 0·01). A similar correlation was present between 30‐kDa domain and albuminuria (r = 0·56, P < 0·01). However, no relationship was found between fibronectin 30‐kDa domain and control of diabetes as assessed by fructosamine concentration. The free N‐terminal fibronectin 30‐kDa domain may be used as a marker of actual endothelial cell dysfunction in diabetes.

Factors influencing arterial stiffness in pheochromocytoma and effect of adrenalectomy

The aim of the study was to evaluate arterial stiffness and its modulating factors measured by carotid-femoral pulse wave velocity (PWV) and central augmentation index (AI) in patients with pheochromocytoma (PHEO) before and after surgery. Forty-five patients with PHEO and 45 healthy controls were investigated using an applanation tonometer (SphygmoCor, AtCor Medical). The gender, age, BMI and lipid profiles were comparable among both groups. The main difference in basic characteristic was as expected for fasting plasma glucose (P<0.001) and all blood pressure modalities. PWV in PHEO was significantly higher than in controls (7.2±1.4 vs. 5.8±0.5 ms−1; P<0.001). Between-group difference in PWV remained significant even after the adjustment for age, heart rate, fasting plasma glucose and each of brachial (P<0.001) and 24 h blood pressure parameters (P<0.01). The difference in AI between groups did not reach the statistical significance (19±14 vs. 16±13%; NS). In multiple regression analysis, age (P<0.001), mean blood pressure (P=0.002), high-sensitive C-reactive protein (hs-CRP) (P=0.007) and 24 h urine norepinephrine (P=0.007) were independently associated with PWV in PHEO. In addition, 27 patients with PHEO were studied 1 year after tumor removal. Successful tumor removal led to a significant decrease in PWV (7.0±1.2 vs. 6.0±1.1 ms−1; P<0.001). In conclusion, patients with PHEO have an increase in PWV, which is reversed by the successful tumor removal. Age, mean blood pressure, hs-CRP and norepinephrine levels are independent predictors of PWV.