Vincenzo Calandrino

Gelatinases and their tissue inhibitors in a group of subjects with obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is associated with an elevated risk of cardiovascular events and stroke. Matrix metalloproteinases (MMPs) are endopeptidases involved in extracellular matrix degradation and then in the development and progression of cardiovascular diseases. Our aim was to evaluate plasma levels of gelatinases (MMP-2 and MMP-9) and their tissue inhibitors (TIMP-1 and TIMP-2) in a group of subjects with OSAS. We enrolled 48 subjects (36 men and 12 women; mean age 49.7 ± 14.68 yrs) with OSAS diagnosed with a 1-night cardiorespiratory study and then we subdivided these subjects into two subgroups according to the apnea/hypopnea index (AHI): Low (L = 21 subjects with AHI <30) and High (H = 27 subjects with AHI >30). We measured plasma concentration of the gelatinases and their inhibitors using ELISA kits. We observed a significant increase in plasma concentration of MMP-9, MMP-2, TIMP-1 and TIMP-2 in the entire group of OSAS subjects and in the two subgroups, with higher levels in the H in comparison with the L subgroup. In the whole group of OSAS subjects we also noted a significant decrease in MMP-9/TIMP-1 ratio in comparison with normal controls. Only MMP-9 was significantly correlated with the severity of the disease, expressed as AHI, with the oxygen desaturation index and also with the mean oxygen saturation. MMPs pattern is altered in OSAS and significantly influenced by the severity of the disease; it probably contributes to the vascular remodeling that leads to the atherosclerotic disease and cardiovascular complications.

Protein carbonyl groups in trained subjects

The purpose of this research was to evaluate the plasma protein carbonyl groups (PC) in 81 trained subjects (TS) who practiced regular, non professional physical activity. They were divided into three groups according to the type of sport they practiced (endurance, mixed or power). On fasting venous blood we examined the PC groups employing an enzyme-linked immunosorbent assay (ELISA) kit, in which 2,4-dinitrophenyl-hydrazine reacts with the PC forming a stable hydrazone product. In the whole group of TS a significant decrease in PC was present, in comparison with sedentary controls (SC). Dividing TS into groups, we observed a decreased PC concentration in those practicing endurance and mixed sports, but not in those practicing power sports. There was no difference between men and women for PC either in SC or in TS; male TS had a PC concentration significantly lower than male SC. Our data show that body proteins are more protected against oxidative stress in subjects who practice endurance and mixed sports. These results give further support to the promotion of regular physical activity including aerobic exercise.

Nitric oxide metabolites (nitrite and nitrate) in young patients with recent acute myocardial infarction

Nitric oxide (NO) has a role in the pathophysiology of acute and chronic cardiovascular events. We studied the plasma concentration of NO stable end products (nitrite and nitrate--NOx) in 43 patients aged<46 years, with recent acute myocardial infarction (AMI). The evaluation was effected at the initial stage, after 3 and 12 months. We subdivided the patients into subgroups according to the number of the main cardiovascular risk factors and to the extent of coronary disease. In the whole group the NOx concentration was initially increased and progressively decreased after 3 and 12 months, remaining at both times significantly higher than in control subjects. The patients with more risk factors had a significantly higher NOx concentration. In conclusion, the persisting high NOx concentration in AMI patients is the expression of a prolonged inflammatory condition and is significantly influenced by the simultaneous presence of several cardiovascular risk factors.

Erythrocyte deformability, plasma lipid peroxidation and plasma protein oxidation in a group of OSAS subjects.

Considering that obstructive sleep apnea syndrome (OSAS) is usually associated with endothelial dysfunction, atherosclerosis and cardiovascular disorders, our aim was to examine the erythrocyte deformability and the oxidative status in a group of OSAS subjects. We consecutively enrolled 48 subjects with OSAS defined after a 1-night cardiorespiratory sleep study, subsequently subdivided according to the apnea/hypopnea index (AHI) value in two subgroups: Low (L = 21 subjects with AHI<30) and High (H = 27 subjects with AHI>30). We evaluated the erythrocyte deformability, expressed as elongation index (EI) and the parameters of the oxidative status, such as lipid peroxidation (expressed as thiobarbituric acid-reactive substances - TBARS) and protein oxidation (measured as carbonyl groups - PC). In the entire group and in the two subgroups of OSAS subjects we found a decreased erytrocyte deformability at all shear stresses, not correlated with the plasmatic oxidative stress nor with the polysomnographic parameters. Lipid peroxidation was increased in the whole group and in the H subgroup of OSAS while protein oxidation showed a different trend. As in OSAS the osmotic fragility and the metabolism of the red cells seem to be not impaired, the oxidative damage to the red cell membrane proteins might be responsible for the reduced erythrocyte deformability. This rheological alteration, in addition to the increase in whole blood and plasma viscosity and to the erythrocyte hyperaggregation, could influence the microcircolatory profile in OSAS subjects.

Influence of risk factors on nitric oxide metabolites at the initial stage of juvenile acute myocardial infarction

Few data are accessible about the nitric oxide (NO) stable end-products (nitrite/NO2 − and nitrate/NO3 − :N O x) in acute coronary syndromes. An increase in inducible NO synthase (iNOS) was found during experimental myocardial infarction [13] and this increase persisted for 2 weeks. In experimental models of acute myocardial infarction (AMI) other authors [2] observed a NOx increase, a correlation between NOx level and iNOS activity and an inhibitory action carried out by S-methylisothiourea, that is an iNOS inhibitor [5]. The NOx level was also measured in a small group of patients with myocardial infarction in whom the peak of NOx elevation occurred 2 and 3 days after the onset of symptoms, suggesting that the NOx increase was dependent on the macrophagical iNOS activation induced by cytokines [1]. Similar results were recently observed in large groups of patients with AMI [6,11]. Now we report the evaluation of the plasma NOx in a group of young patients with recent AMI, subdivided according to the number of main cardiovascular risk factors (RF). We enrolled 105 subjects (97 men and 8 women) aged <46 years; the mean age was 39.6 ± 5.5 years (range 19–45 years). The time interval between AMI onset and the NOx determination was 13 ± 7 days. Regarding the main risk factors, 83% were cigarette smokers or ex-smokers and 49% had family history of coronary artery disease; hypercholesterolemia was present in 51%, essential hypertension in 24% and diabetes mellitus in 12%. According to the number of cardiovascular RF we subdivided AMI subjects into three groups: 33 subjects had 0–1 RF, 35 had 2 RF and 37 had 3–5 RF. On fasting venous blood the NOx level was evaluated by a micromethod which measures the concentration of both NO metabolites (nitrite plus nitrate). At first nitrate was converted into nitrite by a nitrate reductase, then nitrite was measured by spectrophotometry after addition of the Griess reagent. The data were expressed as means ± SD. The statistical difference between normal controls and the subgroups of AMI subjects was examined using the one-way ANOVA model while the Bonferroni posttest was used to compare each pair of subgroups. The obtained results showed that in each subgroup of AMI subjects the mean value of NOx was increased in comparison with normal controls, in whom the NOx level was 24.38 ± 15.67 µM. The mean values of NOx were in fact respectively 57.11±24.75 µM in the subgroup with 0–1 RF, 63.76±31.93 µM

Protein carbonyl groups in trained subjects before and after a cardiopulmonary test

Physical exercise influences the bodys oxidative status. The modifications can involve lipids, proteins and nucleic acids, and different effects seem to be induced by regular and acute exercise respectively. We examined protein oxidation, expressed as concentration of protein carbonyl groups (PC), in trained subjects before (time 0), 10 min (time 1) and 24 hours (time 2) after a cardiopulmonary test performed on a cycloergometer. We enrolled 38 trained subjects (26 men and 12 women), subdivided in two groups (A1 and B1) of 19 subjects each, according to the median value of VO2max, and in two groups (A2 and B2) of 19 subjects each, according to the median value of PC at baseline. PC concentration was measured by an enzyme-linked immunosorbent assay (ELISA). The groups A1 and B1 did not differ from each other as regards the basal PC level and groups A2 and B2 were not different as regards the VO2max. At time 1 PC showed a significant increase in comparison with baseline in trained subjects as a whole group, as well as in each subgroup. At time 2, PC were decreased in comparison with both times 0 and 1 in the whole group and in subgroups A1 and B2, whereas in subgroups A2 and B1 the PC value at time 2 was not different compared to time 0. The percentage increase of PC at time 1 vs time 0, as well as the percentage decrease at time 2 vs time 1 and time 0 respectively, were not different between subgroups A1 and B1. On the contrary, the percentage variations observed at each interval were significantly different between subgroups A2 and B2. The results suggest a reaction of antioxidant systems to acute exercise in trained subjects, influenced by basal PC levels more than by aerobic fitness.