Transport of Low-Density Lipoprotein Into the Blood Vessel Wall During Atherogenic Diet in the Isolated Rabbit Carotid Artery.

BACKGROUND: Atherosclerosis is a chronic fibroproliferative disease that includes accumulation of cholesterol-rich lipids in the arterial wall. Though numerous studies have investigated atherosclerosis, not enough is known about the exact mechanisms of low-density lipoprotein (LDL) transport into the blood vessel wall. Therefore, we explored the (125)I-LDL transport into the arterial wall under constant perfusion flow and pressure as well as the influence of duration of atherogenic diet on (125)I-LDL transport and biomechanical properties of carotid artery. METHODS AND RESULTS: The isolated segment of rabbit carotid artery was used under constant perfusion flow and pressure-induced (0 mmHg and 140 mmHg) blood vessel distension, with the possibility to change and precisely calculate shear stress during the experiment. Obtained results indicate the influence of atherogenic diet duration and consequent variation of shear stress on (125)I-LDL transport into the blood vessel wall. (125)I-LDL transport into the blood vessel wall at low pressure-induced blood vessel distension decreases by the increase of the shear stress and in relation to the atherogenic diet duration. At high pressure-induced blood vessel distension, (125)I-LDL transport increases in relation to the atherogenic diet duration and the increase of shear stress. CONCLUSIONS: The influence of shear stress is a more dominant parameter on LDL uptake at low pressure-induced blood vessel distension; however, the atherogenic diet duration has more of a dominant influence on LDL uptake at high pressure-induced vessel distension.

Histamine blood concentration in ischemic heart disease patients.

The aim of this study was to investigate histamine blood concentration in subjects suffering from different types of ischemic heart diseases during the period of eight days. Our results showed that the histamine blood level was associated with different types of ischemic heart diseases. The blood histamine level in all investigated patients was significantly higher when compared to control subjects (44.87 ± 1.09 ng mL(-1)), indicating the increase of histamine release in patients suffering from coronary diseases. In patients suffering from ACS-UA and ACS-STEMI, the second day peak of histamine level occurs (90.85 ± 6.34 ng mL(-1) and 121.7 ± 6.34 ng mL(-1), resp.) probably as the reperfusion event. Furthermore, our data suggest that histamine can be additional parameter of myocardial ischemia along with cardiac specific enzymes and may prove to be an excellent single prognostic marker for multitude of ischemic heart diseases.

Glucagon effects on 3H-histamine uptake by the isolated guinea-pig heart during anaphylaxis.

We estimated the influence of acute glucagon applications on (3)H-histamine uptake by the isolated guinea-pig heart, during a single (3)H-histamine passage through the coronary circulation, before and during anaphylaxis, and the influence of glucagon on level of histamine, NO, O2 (-), and H2O2 in the venous effluent during anaphylaxis. Before anaphylaxis, glucagon pretreatment does not change (3)H-histamine Umax and the level of endogenous histamine. At the same time, in the presence of glucagon, (3)H-histamine Unet is increased and backflux is decreased when compared to the corresponding values in the absence of glucagon. During anaphylaxis, in the presence of glucagon, the values of (3)H-histamine Umax and Unet are significantly higher and backflux is significantly lower in the presence of glucagon when compared to the corresponding values in the absence of glucagon. The level of endogenous histamine during anaphylaxis in the presence of glucagon (6.9-7.38 × 10(-8) µM) is significantly lower than the histamine level in the absence of glucagon (10.35-10.45 × 10(-8) µM). Glucagon pretreatment leads to a significant increase in NO release (5.69 nmol/mL) in comparison with the period before glucagon administration (2.49 nmol/mL). Then, in the presence of glucagon, O2 (-) level fails to increase during anaphylaxis. Also, our results show no significant differences in H2O2 levels before, during, and after anaphylaxis in the presence of glucagon, but these values are significantly lower than the corresponding values in the absence of glucagon. In conclusion, our results show that glucagon increases NO release and prevents the increased release of free radicals during anaphylaxis, and decreases histamine level in the venous effluent during cardiac anaphylaxis, which may be a consequence of decreased histamine release and/or intensified histamine capturing by the heart during anaphylaxis.

NT-proBNP for prognostic and diagnostic evaluation in patients with acute coronary syndromes.

BACKGROUND AND AIM: N terminal-proB-type natriuretic peptide (NT-proBNP) is synthesised and secreted from the ventricular myocardium. This marker is known to be elevated in patients with acute coronary syndromes (ACS). We evaluated NT-proBNP asa significant diagnostic marker and an important independent predictor of short-term mortality (one month) in patients with ACS. METHODS: NT-proBNP and cardiac troponin I (cTI) were assessed in 134 consecutive patients (median age 66 years, 73% male)hospitalised for ACS in a cardiological university department. The patients were classified into ST-elevation ACS (STE-ACS, n = 74) and non-ST-elevation ACS (NSTE-ACS, n = 60) groups based on the ECG findings on admission. Patients with Killip class ≥ II were excluded. RESULTS: The serum level of NT-proBNP on admission was significantly higher (p < 0.0005), while there was no difference in cTI serum level in the NSTE-ACS patients compared to STE-ACS patients. There was a significant positive correlation between NT-proBNP and cTI in the NSTE-ACS (r = 0.338, p = 0.008) and STE-ACS (r = 0.441, p < 0.0005) patients. There was a significant difference in NT-proBNP (p < 0.0005) and cTI (p < 0.0005) serum level between ACS patients who died within 30 days or who survived after one month. The increased NT-proBNP level is the strongest predictor of mortality in ACS patients, also NT-proBNP cut-point level of 1,490 pg/mL is a significant independent predictor of mortality. CONCLUSIONS: We demonstrated the differences and the correlation in the secretion of NT-proBNP and cTI in patients with STE-ACS vs. NSTE-ACS. Our results provide evidence that NT-proBNP is a significant diagnostic marker and an important independent predictor of short-term mortality in patients with ACS.