A new look at Hsp70 activity in phosphatidylserine-enriched membranes: chaperone-induced quasi-interdigitated lipid phase

70 kDa heat shock protein Hsp70 (also termed HSP70A1A) is the major stress-inducible member of the HSP70 chaperone family, which is present on the plasma membranes of various tumor cells, but not on the membranes of the corresponding normal cells. The exact mechanisms of Hsp70 anchoring in the membrane and its membrane-related functions are still under debate, since the protein does not contain consensus signal sequence responsible for translocation from the cytosol to the lipid bilayer. The present study was focused on the analysis of the interaction of recombinant human Hsp70 with the model phospholipid membranes. We have confirmed that Hsp70 has strong specificity toward membranes composed of negatively charged phosphatidylserine (PS), compared to neutral phosphatidylcholine membranes. Using differential scanning calorimetry, we have shown for the first time that Hsp70 affects the thermotropic behavior of saturated PS and leads to the interdigitation that controls membrane thickness and rigidity. Hsp70-PS interaction depended on the lipid phase state; the protein stabilized ordered domains enriched with high-melting PS, increasing their area, probably due to formation of quasi-interdigitated phase. Moreover, the ability of Hsp70 to form ion-permeable pores in PS membranes may also be determined by the bilayer thickness. These observations contribute to a better understanding of Hsp70-PS interaction and biological functions of membrane-bound Hsp70 in cancer cells.

One-pot Synthesis of Quaternary Pyridinium Salts of Lupane Triterpenoids and Their Antimicrobial Properties

C30-quaternized derivatives of lupane triterpenoids (31 examples) were synthesized with a yield of 85-95% via one-pot functionalization of a double bond under the action of organic tribromides (TEMPO+Br3-, TBABr3, Py·HBr·Br2)...

The Influence of ABCB1 (rs1045642 and rs4148738) Gene Polymorphisms on Rivaroxaban Pharmacokinetics in Patients Aged 80 Years and Older with Nonvalvular Atrial Fibrillation

INTRODUCTION

ABCB1 gene polymorphisms are associated with rivaroxaban distribution changes and adverse reactions but the data are controversial.

AIM

To evaluate the influence of ABCB1 (rs1045642 and rs4148738) gene polymorphisms on rivaroxaban pharmacokinetics in patients aged 80 years and older with nonvalvular atrial fibrillation (NAF).

METHODS

128 patients aged 80 years and older (median [Me] age 87.5 [83.0-90.0] years) with NAF were included. We performed ABCB1 (rs1045642 and rs4148738) genotyping, measured the trough steady-state plasma concentration (C_min,ss) of rivaroxaban and prothrombin time (PT) and analyzed prior medical records for clinically relevant non-major bleeding (CRNMB).

RESULTS

CC genotype carriers had no differences in C_min,ss (p > 0.05) compared with the CT and TT rs1045642 and rs4148738 genotypes carriers. CC genotype carriers had no differences in PT (p > 0.05) compared with the CT rs1045642 and rs4148738 and TT rs4148738 genotypes carriers. In the TT genotype PT levels were higher than in the CC rs1045642 genotype: Me 14.2 [13.0-16.1] sec vs 13.3 [12.4-14.5] sec (p = 0.049). Incidence of CRNMB was higher in patients with the TT genotype compared with the CC rs1045642 (29.3% vs 4.5%, p = 0.021) and rs4148738 (39.3% vs 8.1%, p = 0.008) and the CT genotype rs4148738 (39.3% vs 14.3%, p = 0.002).

CONCLUSION

ABCB1 (rs1045642 and rs4148738) polymorphisms didn't influence rivaroxaban pharmacokinetics in patients aged 80 years and older with NAF. TT carriers developed CRNMB more frequently compared with the CC rs1045642 and the CC and CT rs4148738 genotypes. The haplotype TT-TT haplotype was associated with a higher frequency of CRNMB.

Drug-drug interaction of rivaroxaban and calcium channel blockers in patients aged 80 years and older with nonvalvular atrial fibrillation

Objectives For revealing the peculiarities of the drug-drug interaction of rivaroxaban (substrate CYP3A4 and P-gp) and calcium channel blockers (CCBs) (verapamil - inhibitor CYP3A4 and P-gp and amlodipine - substrate CYP3A4) in patients 80 years and older with nonvalvular atrial fibrillation (NAF) we studied 128 patients. Methods All patients were divided into groups depending on the therapy taken: the 1st - rivaroxaban + amlodipine (n=51), the 2nd - rivaroxaban + verapamil (n=30), the control group - rivaroxaban without CCBs (n=47). A trough steady-state plasma concentration (C min,ss) of rivaroxaban, prothrombin time (PT) in the blood plasma and the event of clinically relevant non-major (CRNM) bleeding were assessed for each patient. Results Patient in group 2 had higher C min,ss of rivaroxaban, PT and CRNM than subjects in the control group (Me 73.8 [50.6-108.8] ng/mL vs. 40.5 [25.6-74.3] ng/mL; Me 14.8 [13.4-17.3] s vs. 13.8 [12.6-14.4] s; 34% vs. 13%, respectively, p<0.05 for all). When compared, the PT and complication rate in group 1 with the control group C min,ss of rivaroxaban were practically the same (p>0.05 for all). Conclusions In patients ≥80 years with NAF, the use of rivaroxaban in combination with verapamil may not be safe and can lead to CRNM bleeding.

Drug-drug interaction of rivaroxaban and calcium channel blockers in patients aged 80 years and older with nonvalvular atrial fibrillation

Objectives For revealing the peculiarities of the drug-drug interaction of rivaroxaban (substrate CYP3A4 and P-gp) and calcium channel blockers (CCBs) (verapamil - inhibitor CYP3A4 and P-gp and amlodipine - substrate CYP3A4) in patients 80 years and older with nonvalvular atrial fibrillation (NAF) we studied 128 patients. Methods All patients were divided into groups depending on the therapy taken: the 1st - rivaroxaban + amlodipine (n=51), the 2nd - rivaroxaban + verapamil (n=30), the control group - rivaroxaban without CCBs (n=47). A trough steady-state plasma concentration (C min,ss) of rivaroxaban, prothrombin time (PT) in the blood plasma and the event of clinically relevant non-major (CRNM) bleeding were assessed for each patient. Results Patient in group 2 had higher C min,ss of rivaroxaban, PT and CRNM than subjects in the control group (Me 73.8 [50.6-108.8] ng/mL vs. 40.5 [25.6-74.3] ng/mL; Me 14.8 [13.4-17.3] s vs. 13.8 [12.6-14.4] s; 34% vs. 13%, respectively, p<0.05 for all). When compared, the PT and complication rate in group 1 with the control group C min,ss of rivaroxaban were practically the same (p>0.05 for all). Conclusions In patients ≥80 years with NAF, the use of rivaroxaban in combination with verapamil may not be safe and can lead to CRNM bleeding.

A violation of emotion regulation as a central link in pathogenesis of stress-induced hypertension

Introduction

Essential hypertension (EH) is one of the most common diseases of the cardiovascular system. Today, scientists discover more and more patients whose BP values during work appear to be higher than those values during free time. This form of EH is called “hypertension at work”.

Objective

To study the role emotion dysregulation in the pathogenesis of EH.

Materials and methods

A projective study of emotion regulation was undertaken with our modified version of Rosenzweig Picture-Frustration Test (Zinchernko, Pervichko). At the second stage of the study, the simulation of emotional stress with the aspiration level modelling was carried out. The level of state anxiety, BP values and levels of catecholamines, renin and angiotonin I were taken before and after the experiment. Eighty-five patients with “hypertension at work” (mean age: 45.9 ± 2.8), 85 patients with “classical” EH (mean age: 47.4 ± 4.5 years) and 82 healthy subjects (mean age: 44.9 ± 3.1) took part in the study.

Results

“Hypertension at work” patients significantly more frequently than patients from the second group and healthy subjects are more prone to rumination, disasterization and repression of their emotions. They will seldom employ the strategy of subjective-objective interactive transformations; their edibility to actualize new meanings in traumatic situations is diminished. We showed that emotion regulation strategies in “hypertension in the work” patients were ineffective in overcoming the emotional tension and created the conditions for chronization of high blood pressure, and could be considerded as the central link in pathogenesis of stress-induced hypertension.

Conclusion

The results contributes to enrich our understanding of etiology and pathogenesis of EH.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Psychological and Psychophysiological Mechanisms of Mental Stress Reaction in Patients with ‘Hypertension at Work’, as Compared with ‘Classical’ Version of Essential Hypertension

Introduction

‘Hypertension at work’ today is found one of the most frequent forms of stress-induced hypertension.

Objectives

To inquire into the specifics of psychological and psychophysiological mechanisms of stress reaction in patients with ‘hypertension at work’, as compared with ‘classical’ essential hypertension (EH).

Materials and methods

The study developed simulation of emotional stress with the aspiration level (AL) modeling. The level of state anxiety (SA), BP values, urine catecholamine levels and levels of renin and angiotonin I in blood plasma were taken before and after the experiment. Eighty-five patients with ‘hypertension at work’ (mean age was 45.9 ± 2.8) and 85 patients with ‘classical’ EH (mean age was 47.4 ± 4.5 years) took part in the study.

Results

Rates of ‘hypertension at work’ patients, when compared with second group patients, revealed a significant increase (Р < 0.001) of systolic BP in response to stress loads (on average, for 16.1 ± 1.9 mmHg and 4.1 ± 0.7 mmHg, respectively). Initially ‘hypertension at work’ patients had significantly lower levels of catecholamines, than the second group, while the levels of renin and angiotensin I were comparable. During the experiment, the patients in the first group showed a significant decrease in all parameters. After the experiment, the patients with ‘HTN at work’ did not show increase of SA, but revealed more frequent inadequacy (69.4%) and instability (56.5%) on the AL. Patients with ‘classical’ EH more often demonstrate adequate AL and lower growth of BP after the experiment.

Conclusions

Patients with ‘hypertension at work’ are more prone to repress their emotions. They reveal physiological features of chronic stress and psychophysiological exhaustion, if compared with second group patients.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Neuropsychological and Motivational Factors of Cognitive Efficiency in Elderly Patients with Essential Arterial Hypertension

Introduction

The diagnostics of cognitive disorders (CD) in patients with essential arterial hypertension (EAH) is often necessary for the choice of treatment strategy.

Objective

To assess the role of neuropsychological and motivational factors in cognitive efficiency of elderly EAH patients.

Materials and methods

Twenty-five patients with EAH took part in the study, stage 1–2, mean age was 67.6 ± 6.1. The assessment of cognitive functions embraced a quantitative measurement of intelligence quotient (IQ) with the Wechsler Adult Intelligence Scale (Wechsler, 1955), and investigation into qualitative features of cognitive processes with Luria's neuropsychological assessment scheme (Luria, 1980) and Zeigarnik's procedure of pathopsychological study (Zeigarnik, 1972).

Results

Within the psychological syndrome structure of CD in EAH patients the leading part is played by the neuro-dynamic factor, manifested in general lability, slowing down, and sudden exhaustion caused by reduction in energy of mental activity. The conclusion is supported by the high frequency of described symptoms among EAH patients and low dynamics of their reduction against the antihypertensive therapy (Pervichko et al., 2014, 2015). However, performance of experimental tasks makes 30% of EAH patients reveal reduced motivation. They would achieve poor results in general scoring, if compared with the group of highly motivated participants. Correlation analysis data show the interconnection between frequency disturbances in motivation and frequency in occurrence of various signs of cognitive decline, such as low efficiency in memorization and delayed recall, as well as low IQ indices.

Conclusions

The data provide a strong argument to support the hypothesis of particular importance of motivational factor of cognitive efficiency in elderly EAH patients.

Disclosure of interest

The authors have not supplied their declaration of competing interest.