Jan Gmiński

Evaluation of elastin metabolism in children from families with high risk of atherosclerosis.

Markers of elastin metabolism were estimated in sera of children from families with a high risk of atherosclerosis (ATH). There was no statistically significant difference in the serum elastase-like activity between the groups studied. The concentration of elastin-derived peptides was statistically significantly elevated in the ATH group. Anti-elastin antibodies were found to be present in 73% of ATH children, while they circulated in 5% of control subjects only. Antibodies observed in the youngest ATH children were of the IgM type, suggesting the initial stage of the autoimmunization to elastin. The data obtained in this study may indicate an enhanced metabolism of elastin in ATH children.

The influence of angiotensin-converting enzyme inhibitors on the aorta elastin metabolism in diet-induced hypercholesterolaemia in rabbits

Aortic elastin turnover is significantly accelerated in atherosclerosis, partly because of activation of the renin-angiotensin-aldosterone system caused by hypercholesterolaemia. We postulated that angiotensin-converting enzyme inhibitors (ACE-I) prevent the aortic elastin loss in experimental hypercholesterolaemia. Two doses of ACE-I (captopril, enalapril and quinapril) were used: a dose equivalent to that applied to human subjects and a dose 10 times higher. We found that the increase in serum and aortic elastolytic activity in cholesterol-fed rabbits was prevented by high-dose captopril. The elastin content in aorta homogenates from cholesterol-fed rabbits was significantly decreased. The higher dose of captopril, but no other ACE-I, prevented this decrease in aortic elastin content. In cholesterol-fed rabbits the elastin-bound calcium content was significantly elevated. The higher doses of captopril and enalapril lowered the elastin-bound calcium content. In serum and aortic homogenates of cholesterol-fed rabbits, ACE activity was elevated by 15% and 77%, respectively. Both doses of captopril, enalapril and quinapril prevented this cholesterol-induced increase in serum and aortic ACE activity. We conclude that: 1) administration of captopril at doses 10 times higher than those used in humans prevents hypercholesterolaemia increased aortic elastin loss. 2) higher doses of captopril and enalapril prevent the hypercholesterolaemia-induced increase in aortic elastin-bound calcium.

Anti-elastin antibodies in patients with lung cancer

The aim of this study was to investigate anti-elastin antibodies of the IgG and IgM types in sera of patients suffering from lung cancer, using the DOT immunobinding assay. We studied 96 pathological and 40 control sera. Anti-elastin antibodies were found to be present in 45% of patients with small cell lung cancer, 19% of subjects with adenocarcinoma and not-identified lung tumor and 15% of patients with squamous cell lung cancer. They circulated in 5% of control persons only. The highest values of their titers were observed in the advanced stages of disease. In 55% of anti-elastin antibody positive small cell lung cancer patients, antibodies were of the IgM type, suggesting the initial step of the autoimmunization to elastin.

The antioxidant enzymes activity in the conditions of systemic hypersilicemia

The effect of an excessive inorganic silicon oral intake on the activity of basic antioxidant enzymes was studied in rats. Activities of superoxide dismutase, catalase, and glutathione peroxidase were measured in liver and kidney tissues of animals receiving per os sodium metasilicate nonahydrate (Na2SiO3.9H2O) (Sigma, [St. Louis, MO]) dissolved in their drinking water. A decrease of the activity of all the studied enzymes was found in the samples derived from the experimental group. The results obtained indicate the free oxygen radicals participation in the potential pathologic events in the conditions of systemic hypersilicemia.

The effect of silicon (Si) on lipid parameters in blood serum and arterial wall.

The influence of silicon treatment on the levels of lipid parameters of blood serum and aortic wall was studied in rats. The concentrations of total cholesterol, phospholipids, triglycerides, HDL-cholesterol, LDL-cholesterol, and HDL-phospholipids were measured in sera of rats receivingper os a soluble, inorganic silicon compound — sodium metasilicate nonahydrate (Na2SiO3·9H2O) — dissolved in the drinking water. In the aortic tissue levels of total cholesterol, triglycerides and phospholipids were estimated. An increase in HDL-cholesterol and HDL-phospholipid concentrations, with a simultaneous decrease of LDL-cholesterol and triglyceride levels, was observed in the sera of the tested group. The levels of total cholesterol and phospholipids in the sera, as well as the concentrations of lipids in the aortic walls, showed no significant differences. The results obtained could provide evidence for the existence of an additional mechanism of silicon antiatheromatous action, concerning the modification of activity of enzymatic systems involved in lipids metabolism.

Modulation of elastase-like activity in fibroblasts stimulated with elastin peptides

Elastin-derived peptides, kappa-elastin, prepared by chemical degradation of insoluble elastin from bovine ligamentum nuchae, were shown to increase the elastase-like activity in the culture medium and cell fractions in fibroblasts. Preincubation of cells with nifedipine (calcium channel blocker) and trifluoperazine (calmodulin antagonist) induced a decrease in the activities of the enzyme under study. These data suggest the possibility of pharmacological modulation of the biological effects induced by elastin-derived peptides.

Surveyor Nuclease Detection of Mutations and Polymorphisms of mtDNA in Children

Mitochondrial encephalomyopathies are complex disorders with wide range of clinical manifestations. Particularly time-consuming is the identification of mutations in mitochondrial DNA. A group of 20 children with clinical manifestations of mitochondrial encephalomyopathies was selected for molecular studies. The aims were (a) to identify mutations in mtDNA isolated from muscle and (b) to verify detected mutations in DNA isolated from blood, in order to assess the utility of a Surveyor nuclease assay kit for patient screening. The most common changes found were polymorphisms, including a few missense mutations altering the amino acid sequence of mitochondrial proteins. In two boys with MELAS (i.e., mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes), a mutation A→G3243 was detected in the tRNALeu gene of mtDNA isolated from muscle and blood. In one boy, the carrier status of his mother was confirmed, based on molecular analysis of DNA isolated from blood. A method using Surveyor nuclease allows systematic screening for small mutations in mtDNA, using as its source blood of the patients and asymptomatic carriers. The method still requires confirmation studying a larger group. In some patients, the use of this method should precede and might limit indications for traumatic muscle and skin biopsy.

Silicon metabolism. The interrelations of inorganic silicon (Si) with systemic iron (Fe), Zinc (Zn), and copper (Cu) pools in the rat.

The influence of silicon treatment on the levels of trace elements zinc (Zn), copper (Cu), and iron (Fe) in serum and tissues was studied in rats. The concentrations of silicon, iron, and zinc were estimated in samples of sera and tissues of rats receivingper os a soluble, inorganic silicon compound—sodium metasilicate nonahydrate (Na2SiO3·9H2O), dissolved in the drinking water. An increase of copper concentrations in liver and aortic walls in the experimental group was observed, with simultaneous reduction of zinc amounts in serum and all the tissue samples in the course of the experiment. The iron concentrations in the analyzed samples did not show any significant changes between both groups. The silicon levels in serum and in all the examined tissues were significantly higher in the tested group.The results provide evidence for the silicon interaction with copper and zinc, which could result in a number of metabolic process modifications, antiatheromatous activity among them.

Pharmacological modulation of the antioxidant enzymes activities and the concentration of peroxidation products in fibroblasts stimulated with elastin peptides

1. Elastin peptides (kappa-elastin) prepared by alcoholic potassium hydroxide degradation of insoluble elastin were shown to increase the activities of antioxidant enzymes (SOD, CAT, GSH-Px) and the lipid peroxide concentration within fibroblasts. 2. The preincubation of cells with nifedipine (calcium channel antagonist) and trifluoperazine (calmodulin antagonist) caused the decrease in the activities of studied enzymes and the concentration of TBA-reactive products in fibroblasts stimulated with kappa-elastin. 3. The preincubation with ketotifen (antiallergic drug) has no effect on the activities of SOD, CAT, GSH-Px and the lipid peroxide concentration in stimulated cells. 4. These data suggest the possibilities of pharmacological modulation of the biological effects induced by elastin-derived peptides.

The influence of angiotensin-converting enzyme inhibitors on the aorta elastin metabolism in diet-induced hypercholesterolemia in rabbits

Aortic elastin turnover is significantly accelerated in atherosclerosis, partly because of activation of the renin-angiotensin-aldosterone system caused by hypercholesterolaemia. We postulated that angiotensin-converting enzyme inhibitors (ACE-I) prevent the aortic elastin loss in experimental hypercholesterolaemia. Two doses of ACE-I (captopril, enalapril and quinapril) were used: a dose equivalent to that applied to human subjects and a dose 10 times higher. We found that the increase in serum and aortic elastolytic activity in cholesterol-fed rabbits was prevented by high-dose captopril. The elastin content in aorta homogenates from cholesterol-fed rabbits was significantly decreased. The higher dose of captopril, but no other ACE-I, prevented this decrease in aortic elastin content. In cholesterol-fed rabbits the elastin-bound calcium content was significantly elevated. The higher doses of captopril and enalapril lowered the elastin-bound calcium content. In serum and aortic homogenates of cholesterol-fed rabbits, ACE activity was elevated by 15% and 77%, respectively. Both doses of captopril, enalapril and quinapril prevented this cholesterol-induced increase in serum and aortic ACE activity. We conclude that: 1) administration of captopril at doses 10 times higher than those used in humans prevents hypercholesterolaemia increased aortic elastin loss. 2) higher doses of captopril and enalapril prevent the hypercholesterolaemia-induced increase in aortic elastin-bound calcium.