New type of BACE1 siRNA delivery to cells.

BACKGROUND: Small interfering RNA (siRNA) gene therapy is a new molecular approach in the search for an efficient therapy for Alzheimer disease (AD), based on the principle of RNA interference. Reducing BACE activity can have great therapeutic potential for the treatment of AD. In this study, receptor-mediated delivery was used to deliver opioid peptide-conjugated BACE 1 to INR-32 human neuroblastoma cells. MATERIAL AND METHODS: An INR-32 human neuroblastoma cell line was stably transfected to express the APP cDNA coding fragment containing the predicted sites for cleavage by α, ß, or γ-secretase. This was then treated with BACE 1 siRNA to silence BACE gene expression. BACE gene transcription and translation was determined using BACE-1 siRNA cross-linked with opioid peptide, together with RT-PCR, Western blot analysis, and ELISA. RESULTS: Receptor-mediated delivery was used to introduce BACE1 siRNA to the APP - INR 32 human neuroblastoma cells. Decreased BACE mRNA and protein expression were observed after the cells were transfected with BACE1 siRNA. CONCLUSIONS: Delivery of BACE1 siRNA appears to specifically reduce the cleavage of APP by inhibiting BACE1 activity.

The study of t-PA, u-PA and PAI-1 genes polymorphisms in patients with abdominal aortic aneurysm.

The most important feature of abdominal aortic aneurysm (AAA) pathogenesis is an enzymatic degradation of elastic lamellae and extracellular matrix proteins particularly with participation of matrix metalloproteinases. Plasmin, which is responsible for the dissolution of fibrin in blood vessels, plays also a key role in the cascade for activation of the metalloproteinases. The purpose of this study was to evaluate the influence of selected polymorphisms in genes coding for tissue plasminogen activator (-7351 C/T polymorphism), urokinase-type plasminogen activator (1788 C/T polymorphism) and plasminogen activator inhibitor 1 (-675 4G/5G and -844 G/A polymorphism) on the susceptibility to AAA. We performed a case-control study of 153 polish patients hospitalized due to AAA and compared them with matched healthy control subjects. The polymorphisms were ascertained through genotyping by polymerase chain reaction and restriction digestion of amplified fragments or through high-resolution melting analysis. In this study we have found lower frequency of wild-type GG genotype of the -844G/A PAI-1 polymorphism in cases than in controls, what may suggest the protective effect of this genotype for the risk of AAA development. None of the remaining polymorphisms tested were associated with AAA occurrence.

Association analysis of genetic polymorphisms of factor V, factor VII and fibrinogen ß chain genes with human abdominal aortic aneurysm.

Increased activity of the coagulation system is associated with the increased risk of many arterial thrombotic diseases and atherosclerosis. The purpose of this study was to evaluate the influence of selected polymorphisms in genes coding for coagulation factor V (1691 G/A, the so-called Leiden mutation), factor VII (-323 0/10 bp insertion/deletion) and fibrinogen ß chain (-455 G/A) on the risk of abdominal aortic aneurysm, a particular form of atherothrombosis. We conducted a case-control study of 153 Polish patients hospitalized due to abdominal aortic aneurysm (AAA) and compared the results to those obtained from matched healthy control subjects. The polymorphisms were ascertained through genotyping by polymerase chain reaction and restriction digestion of amplified fragments. The study revealed that individuals carrying heterozygous genotype GA for the fibrinogen ß chain -455 G/A mutation had at least a 2-fold greater likelihood of AAA development compared to control subjects (OR=3.01; 95% CI 1.83-4.96). The cases possessing homozygous mutant genotype (AA) had no significant risk of developing AAA compared to the control subjects (OR=1.12; 95% CI 0.33-2.44; p=0.83). Concerning factor V 1691 G/A and factor VII -323 0/10 bp mutations, we did not find any statistically significant correlation between them and AAA occurrence. In conclusion, we suggest that the -455G/A polymorphism of the fibrinogen ß chain gene is a potential genetic marker to identify the risk of AAA.

Does atrial fibrillation affect plasma endothelin level?

BACKGROUND: Atrial fibrillation (AF) may result in endocardial endothelium dysfunction. The main objective of the study was to evaluate the plasma concentration of endothelin-1 (ET-1) during persistent AF and after sinus rhythm recovery following direct-current cardioversion and to assess the predictive value of ET-1 in AF patients. METHODS: The study group consisted of 43 patients with persistent AF and normal left ventricle systolic function who had undergone successful cardioversion. Blood samples were collected twice: 24 hours before and 24 hours after cardioversion. All patients were also examined in terms of sinus rhythm maintenance on the 30th day after cardioversion. RESULTS: There were no differences in ET-1 plasma concentration between the persistent AF group and the control group (2.6 ± 2.9 fmol/mL vs 2.3 ± 4.5 fmol/mL, NS). Plasma ET-1 levels did not change within 24 hours after successful cardioversion (2.5 ± 2.8 fmol/mL vs 2.6 ± 2.9 fmol/mL, NS). There was no correlation between the baseline plasma levels of ET-1 in patients with persistent AF and sinus rhythm maintenance 30 days after cardioversion. CONCLUSIONS: Persistent AF does not affect plasma ET-1 concentration in patients with normal left ventricle systolic function and with no symptoms of heart failure. There are no significant changes in plasma ET-1 level during the 24 hours after cardioversion.

B-type natriuretic peptide level after sinus rhythm restoration in patients with persistent atrial fibrillation - clinical significance.

BACKGROUND: Persistent atrial fibrillation (AF) leads to electrical, structural and neurohormonal remodelling of the atria, including increased plasma B-type natriuretic peptide (BNP) level. AIM: To assess the clinical value of plasma BNP or NT-proBNP concentrations in patients with persistent AF measured before and after sinus rhythm restoration following direct-current cardioversion. METHODS: The study group consisted of 43 patients with persistent AF who underwent successful electrical cardioversion. The mean AF duration was 12.3 weeks. Patients in the study group had no symptoms of heart failure and they had preserved left ventricular systolic function. Blood samples were collected twice: 24 hours before and 24 hours after electrical cardioversion. Logistic regression analysis was used to assess the predictive value of BNP and NT-proBNP levels. RESULTS: Baseline NT-proBNP and BNP levels were increased in patients with persistent AF (290.9 +/- 257.2 pg/mL and 148.4 +/- 111.4 pg/mL, respectively) compared to a matched control group without AF (47.8 +/- 80.6 pg/mL; p = 0.0001 and 74.9 +/- 81.7 pg/mL; p = 0.01). Plasma BNP level decreased 24 hours after cardioversion (from 148.4 +/- 111.4 to 106.4 +/- 74.7 pg/mL; p = 0.0045) whereas NT-proBNP level did not (from 290.9 +/- 257.2 to 262.7 +/- 185.6 pg/mL; NS). During an 18-month follow-up period, 21 (49%) patients remained in sinus rhythm. Neither baseline plasma BNP nor NT-proBNP level predicted sinus rhythm maintenance. CONCLUSIONS: NT-proBNP and BNP plasma levels are increased in patients with persistent AF. Conversion to sinus rhythm is associated with a significant decrease in plasma BNP but not NT-proBNP level. Baseline BNP and NT-proBNP levels do not predict long-term sinus rhythm maintenance.

Plasma NT-proANP in patients with persistent atrial fibrillation who underwent successful cardioversion.

BACKGROUND: Atrial fibrillation (AF) decreases quality of life and significantly increases risk of stroke, congestive heart failure and death. Atrial overload and stretch also result in increased production of natriuretic peptide type A (ANP). The biologically inactive prohormone NT-proANP is released to plasma in the same amounts as ANP but it has higher levels in the blood due to decreased degradation in vivo. In vitro degradation is also slower and NT-proANP may be an interesting alternative for ANP. AIM: To evaluate NT-proANP plasma concentration in patients with persistent AF following successful cardioversion. METHODS: The study group consisted of 43 patients with persistent AF and normal left ventricular systolic function, who underwent successful electrical cardioversion (EC). The control group comprised 20 patients with sinus rhythm without a history of AF. Blood samples were collected twice, during visits 24 h before and after EC. All patients were also examined 30 days after the sinus rhythm recovery. The NT-proANP concentration was measured using an immunochemical method (ELISA). RESULTS: Plasma NT-proANP concentration was significantly increased in patients with persistent AF compared to the control group (4.8 +/- 2.9 vs. 2.8 +/- 1.2 nmol/l, p = 0.004). Plasma NT-proANP level decreased significantly after successful cardioversion (to 3.2 +/- 2.4 nmol/l; p < 0.0001). There was no correlation between the baseline NT-proANP concentration and sinus rhythm maintenance during 30 days after EC. CONCLUSIONS: Plasma NT-proANP concentration is higher in patients with persistent AF and normal left ventricular systolic function than in patients without arrhythmia. Sinus rhythm recovery due to EC leads to a decrease of plasma NT-proANP. The baseline NT-proANP level has no prognostic value for prediction of sinus rhythm maintenance during 30 days after EC.

A decrease in serum aldosterone level is associated with maintenance of sinus rhythm after successful cardioversion of atrial fibrillation.

BACKGROUND: The activation of the renin-angiotensin-aldosterone system has been implicated in the progression of atrial structural remodeling during atrial fibrillation (AF). However, consequences of the changes of aldosterone in AF have not been evaluated. OBJECTIVES: This study's aim was to evaluate changes of serum aldosterone concentration after successful cardioversion of persistent AF and to determine the prognostic value of these changes. METHODS: The prospective, single center study included 45 consecutive patients with nonvalvular persistent AF and preserved left ventricular systolic function, referred for cardioversion. None of the patients were taking aldosterone antagonists. Blood samples for aldosterone measurement were collected twice: 24 hours before and 24 hours after cardioversion. RESULTS: Forty-three patients were successfully converted to sinus rhythm. On the 30th day following cardioversion, 24 patients maintained sinus rhythm (group A), 19 patients relapsed to AF (group B). Serum aldosterone concentration before cardioversion did not differ significantly between both groups (175.6 +/- 112.82 pg/mL vs 125.8 +/- 51.2 pg/mL; P = 0.25). However, in group A serum aldosterone level decreased significantly within 24 hours after cardioversion, from 175.6 +/- 112.8 pg/mL to 101.4 +/- 44.2 pg/mL (P = 0.0034). In group B, the aldosterone level before and after cardioversion did not differ significantly (125.8 +/- 51.2 pg/mL vs 118.2 +/- 59.6 pg/mL; P = 0.68). Logistic regression analysis revealed that a decrease in plasma aldosterone concentration after direct current cardioversion more than 13.2 pg/mL predicted sinus rhythm maintenance in a 30-day follow-up, with 87% sensitivity and 64% specificity. CONCLUSIONS: There is a positive correlation between the fall in aldosterone concentration 24 hours after cardioversion and maintenance of sinus rhythm during 30 days of observation.

Persistent atrial fibrillation is not associated with thrombomodulin level increase in efficiently anticoagulated patients.

INTRODUCTION: Atrial fibrillation (AF) is the most common arrhythmia and leads to a five-fold increased risk of stroke compared to persons with sinus rhythm. A soluble form of thrombomodulin (sTM) is a recognized marker of endothelial dysfunction and may contribute to the hypercoagulable state in AF. The aim of the study was to evaluate plasma concentration of sTM in persistent AF patients before and after sinus rhythm recovery following direct current cardioversion (CV). MATERIAL AND METHODS: In 45 effectively anticoagulated consecutive patients, with persistent non-valvular AF, and normal left ventricular function, CV was performed. Blood samples for sTM assessment were collected twice: 24 hours before and 24 hours after CV. RESULTS: In 43 patients sinus rhythm was obtained. The mean plasma sTM level was significantly lower in AF patients compared to the control group with sinus rhythm and without anticoagulation (38.5 ±9.9 ng/ml vs. 44.1 ±9.1 ng/ml, p = 0.04). Plasma sTM levels did not change 24 hours after successful CV (36.7 ±9.5 ng/ml vs. 38.5 ±9.9 ng/ml, p = 0.16). CONCLUSIONS: Plasma sTM concentration was lower in patients with persistent AF and normal left ventricle systolic function than in patients with sinus rhythm, presumably due to chronic oral anticoagulant therapy in the AF group. CV has no impact on sTM plasma level evaluated 24 hours after sinus rhythm restoration.