Gelatinases A and B and Antioxidant Enzyme Activity in the Early Phase of Acute Myocardial Infarction.

Oxidative stress plays important roles in the pathophysiology of acute myocardial infarction (AMI). The aim of this study was to investigate the correlation of the oxidative stress status and matrix metalloproteinase activity in AMI patients in comparison to controls. This study included 136 subjects: 68 patients with AMI (42 males/26 females; mean age 58.5 ± 10.5 years) and 68 controls (37 males/29 females; mean age 60.2 ± 12.4 years). Gelatinases A and B were assayed using gelatin zymography, enzyme activities were obtained spectrophotometrically. Gelatinase A and B activities were increased in the AMI patients' group compared to the control. Activities of serum superoxide dismutase (SOD) and xanthine oxidase (XO) were significantly higher in AMI patients (106.53 ± 23.45 U/l, P < 0.001 and 158.18 ± 29.59 U/l, P < 0.001) than in the control group (55.99 ± 10.79 U/l and 79.81 ± 7.93 U/l). The activity of catalase (CAT) in the sera of AMI patients was lower (271.31 ± 7.53 U/l, P < 0.005) than in the control group (305.94 ± 97.28 U/l). Plasma glutathione peroxidase (GPx) and glutathione reductase (GR) in AMI patients were significantly higher (582.47 ± 184.81 U/l, P < 0.001 and 59.64 ± 21.88 U/l, P < 0.001) than in the control group (275.32 ± 104.69 U/l and 47.71 ± 20.05 U/l). The present findings demonstrate activation of gelatinases A and B and oxidative stress markers in the early stage of AMI. Gelatinases, detected at high levels in AMI patients only, indicate their noticeable predisposition for becoming additional biomarkers of the early phase of AMI.

Matrix Metalloproteinase-2 and -9, Lactate, and Malate Dehydrogenase and Lipid Peroxides in Sera of Patients with Colorectal Carcinoma.

Matrix metalloproteinases (MMPs) are involved in tumour invasion and metastasis of colorectal carcinoma. Oxidative stress represents one of the possible mechanisms that activate inactive MMPs. Oxidative stress increases lipid peroxidation, which causes impaired membrane permeability and leakage of lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) into circulation. Our aim was to assess the activity of MMP-2 and MMP-9 and its relation to the parameters of oxidative stress and membrane damage markers in patients with different TNM (tumour, lymph nodes, metastasis) stages of colorectal carcinoma. MMP-2 and -9 activities were evaluated by gelatin zymography. Oxidative stress was examined by quantifying serum malondialdehyde (MDA) concentration. LDH and MDH activities were determined spectrophotometrically. The activities of MMP-2 and -9 were significantly higher in the sera of colorectal carcinoma patients when compared to healthy subjects. There was a stage-dependent increase in relative MMP-2 activity compared to the overall serum gelatinolytic activity. The activity of MMP-9 was the highest in TNM III. The MDA concentration and the LDH and MDH activities were significantly higher in colorectal carcinoma patients than in controls, while LDH and MDH activities were stage dependent. There was significant correlation between serum MMP-2 and LDH activity in TNM II, III and IV patients. A stage-dependent increase of LDH and MDH activity was observed. We highlight here that MMP-9 could be a 100% sensitive marker of TNM stage III of colorectal carcinogenesis. In this study it was shown for the first time that gelatinolytic activity in colorectal carcinoma is associated with redox imbalance.

Effect of captopril on serum lipid levels and cardiac mitochondrial oxygen consumption in experimentally-induced hypercholesterolemia in rabbits.

Angiotensin converting enzyme inhibitors are widely used in therapy of cardiovascular diseases. However, the consensus on effects of these inhibitors in control of myocardial oxygen consumption during the process of experimental hypercholesterolemia and under the condition of endothelial dysfunction has not been reached. Here we examined effects of captopril, an angiotensin converting enzyme inhibitor, on serum lipid levels and oxygen consumption rate in mitochondria isolated from heart of rabbits treated by hypercholesterolemic diet. During the twelve-week period, the Chinchilla male rabbits were daily treated by saline (controls); 1 % cholesterol diet; 5 mg/kg/day captopril or 1 % cholesterol + 5 mg/kg/day captopril. Total- and high-density lipoprotein cholesterol and triglyceride in serum were measured spectrophotometrically. The left ventricle mitochondrial fraction was isolated and myocardial oxygen consumption was measured by Biological Oxygen Monitor. Mitochondria isolated from hearts of rabbits exposed to hypercholesterolemic diet showed significantly reduced respiration rates (state 3 and state 4) with altering adenosine diphosphate/oxygen ratio, whereas the respiratory control ratio was not affected when compared to controls. Mitochondria from cholesterol/captopril-treated animals showed significantly reduced respiration rates without altering adenosine diphosphate/oxygen ratio index or respiratory control ratio. Although captopril did not exert the favorable effect on serum lipid levels in cholesterol-treated animals, it restored the mitochondrial oxygen consumption. Further studies should be performed to define the underlying physiological and/or pathophysiological mechanisms and clinical implications.

[Diurnal fluctuations of protein contents and the pH dependence of beta2-microglobulin stability in urine].

Diurnal fluctuations of protein excretion into urine and the effect of urinary pH on the urinary protein concentrations were studied in patients with various kidney diseases. The diurnal kinetics of gamma-immunoglobulin, transferrin, albumin, alpha1-microglobulin, gamma-immunoglobulin light chains, and the retinol-binding protein proved to positively correlate with the diurnal fluctuations of proteinuria and to negatively correlate with urinary pH. Diurnal changes in urinary beta2-microglobulin content did not correlate with those of any other protein. Oral bicarbonate intake alkalinized the urine, increased the urinary beta2-microglobulin content, and led to a direct correlation between beta2-microglobulin excretion and excretion of other low-molecular proteins. Thus, proteinuria, single protein excretion, and urinary pH displayed diurnal rhythmicity in the patients; beta2-microglobulin was unstable in acid urine and its urinary level depended on the urinary pH.