Chemopreventive activity of fluphenazine and its analogues in human lymphocyte cultures preincubated with ceramide synthase inhibitor

Wstęp. Ceramid (cer) jest zazwyczaj produkowany na drodze hydrolizy sfingomieliny przez sfingomielinazy (SMase). Zbadano, że aktywność chemoprewencyjna — propoptotyczna i chemouwrażliwiająca — piperazynowej pochodnej fenotiazyny (Pht), flufenazyny (FPh) i jej nowo syntezowanych analogów — związków 1b i 3f — zależy od stymulacji lizosomalnej, kwaśnej sfingomielinazy (aSMase), niezależnej od Zn2+, jednego z enzymów uczestniczących w powsta­waniu endogennego cer. Innym ważnym szlakiem tworzenia cer w komórce jest synteza de novo z udziałem syntetazy ceramidowej (CerS). Celem pracy była ocena aktywności chemoprewencyjnej FPh i jej analogów: związków 1b i 3f po nieodwracalnym zablokowaniu CerS. Materiał i metody. Aktywność chemoprewencyjną badanych związków (10 μM, 2 godz.) oceniano w hodowlach limfocytów ludzkich uszkodzonych genotoksycznie przez inkubację z benzo[a]pirenem (+B[a]P; 7,5 μM, 48 godz.) i po preinkubacji z selektywnym inhibitorem CerS — fumonizyną B1 (+FB1; 20 μM, 1,5 godz.). W ocenie efektów badanych związków zastosowano metody: mikroskopii fluorescencyjnej, spektrofotometrii i spektrofluorymetrii. Istotność statystyczną uzyskanych rezultatów sprawdzono za pomocą testu t-Studenta. Wyniki. W hodowlach limfocytów w obecności inhibitora CerS (+B[a]P; +FB1) inkubacja hodowli z analogami 1b i 3f prowadziła do istotnie niższego (p < 0,05) odsetka komórek w apoptozie i akumulacji rodaminy 123 (Rod-123) w po­równaniu z hodowlą bez inhibitora CerS (+B[a]P; -FB1). W przypadku macierzystego związku FPh wpływ na hodowle limfocytów nie zależał od obecności inhibitora CerS. Wnioski. Efekty proapoptotyczny i chemouwrażliwiający analogów 1b i 3f są uwarunkowane aktywacją CerS. Nato­miast dla macierzystej FPh wykazano, że jej aktywność chemoprewencyjna nie zależy od stymulacji szlaku syntezy de novo cer z udziałem CerS.Introduction. The ceramide (cer) is generated mainly via hydrolysis of sphingomyelin by sphingomeylinase (SMase). It was previously documented that chemopreventive activity — proapoptotic and chemosensitizng of piperazine phenothiazine derivative, fluphenazine (FPh) and its newly synthesized analogues, 1b and 3f compounds, depends on the activity of lysosomal acidic sphingomyelinase (aSMase), Zn2+-independent, one of the enzymes participating in intracellular ceramide generation. Another important pathway of intracellular formation of ceramide is de novo synthesis with participation of ceramide synthase (CerS). The aim of this research is to assess the chemopreventive activity of FPh and 1b and 3f compounds after irreversible CerS blockade. Material and methods. Chemopreventive activity of the tested compounds (10 μM, 2 h) was evaluated in hu­man lymphocyte cultures, genotoxically damaged by benzo[a]pyrene (+B[a]P; 7,5 μM, 48 h) and preincubated with a selective inhibitor CerS — fumonisin B1 (+FB1; 20 μM, 1,5 h) and inspected with fluorescence microscopy, as well as with spectrophotometric and spectrofluorimetric methods. Student’s t-test was used for testing the statistical significance of the results. Results. It was established that in the presence of the CerS inhibitor (+B[a]P; +FB1) the effects of 1b and 3f analogues on apoptotic cell frequency in lymphocyte cultures and on accumulation of rhodamine 123 (Rod-123), were signifi­cantly (p < 0.05) decreased when compared to the cultures carried out in the absence of the CerS inhibitor (+B[a]P; -FB1). Whereas in the case of the parent compound: the FPh, the presence of the inhibitor did not influence on FPh chemopreventive activity. Conclusions. The proapoptotic and chemosensitizing effects of 1b and 3f compounds were determined in major part by CerS activation. Also the chemopreventive activity of the parent compound: the FPh, was independent of the cer de novo synthesis pathway conducted by CerS

Medium-term prognosis of survival and hospitalization of patients after permanent pacemaker implantation based on BNP, high-sensitivity troponin T, and left atrium volume index

Introduction : Determination of predictors of survival and hospitalization can optimise a medical care of patient with permanent pacemaker. Aim of the research : Use of the B-type natriuretic peptide (BNP), high-sensitivity troponin T (TnT hs), and left atrial volume index (LAVI) to control survival and hospitalizations due to cardiovascular causes in patients after pacemaker implantation. Material and methods : The study covered a sample of 123 patients qualified for pacemaker implantation. During 23-month observation, cyclic BNP, TnT hs and LAVI examinations were performed. Mortality and hospitalization rate in groups with normal and elevated values were assesed using Kaplan-Meier curves. Results : A statistical relationship was observed between survival and increased initial BNP plasma level (log-rank test = 2.11, p < 0.05). Significantly higher frequency of hospitalizations was observed with a higher initial BNP plasma level (log-rank test = 2.01, p < 0.05). No statistically significant relationships were found between the TnT hs concentration and the duration of survival and hospitalizations. A strong tendency was confirmed (p < 0.10) towards a higher probability of the survival of patients with low values of LAVI, compared to patients with high values of LAVI. Conclusions : Results of the study conducted in regional centre (over 1000 implantations per year) confirmed that BNP peptide is an important indicator of survival and hospitalization due to cardiovascular causes after permanent pacemaker implantation. From among the 3 parameters examined: BNP, TnT hs LAVI, only BNP peptide and LAVI may be justified in the evaluation of patients after pacemaker implantation. Determination of BNP for evaluation medium-term prognosis of survival and hospitalization may be considered during routine pacemaker control visit

Correlation analysis of the relationship between B-type natriuretic peptide and selected echocardiographic parameters in patients with permanent pacemakers

Introduction: The present study was undertaken to evaluate the practical value of BNP measurements and echocardiographic left ventricular volume index in patients with permanent pacemakers because there are no such reports in the literature. Aim of the research: The aim of the study was to reveal multiple correlations between BNP levels and selected echocardiographic parameters of the left atrium in patients with permanent pacemakers. In the literature there are reports on the significance of BNP values and left atrial size in patients with permanent pacemakers. The results of the present study appear to be of value in the outpatient assessment of these patients. Material and methods: We analysed a group of 117 patients with permanent pacemakers (AAI/R 21 patients, DDD/R 59 patients, VVI/R 37 patients) and 48 healthy volunteers serving as the control group. BNP measurements were performed on venous blood samples using Triage meters. The Simpson method and the ellipse method were used to assess the left atrium on echocardiography. Results: There was a significant correlation between BNP and maximum left atrial volume, minimum left atrial volume, and left atrial volume index in patients with AAI/R, DDD/R, and VVI/R pacemakers at 3 and 6 months after the implantation. Conclusions : In patients after implantation of permanent pacemakers there are correlations between BNP values and echocardiographic left atrial parameters, especially in patients with DDD/R pacemakers. Left atrial function improves in patients with DDD/R pacemakers. Pacemaker check-up should be extended to include BNP measurements and echocardiographic assessment of the left atrium