Beta-adrenergic Responsiveness Research Articles

SPECTROPHOTO AND DIGITAL COLORIMETRIC DETERMINATION INDICATOR OF BETA-ADRENOREACTIVITY OF ERYTHROCYTE MEMBRANES OF PATIENTS WITH BRONCHIAL ASTHMA

The change in the adrenoreactive properties of membrane and cellular structures under the influence of catecholamines makes it possible to consider the beta-adrenergic reactivity of the erythrocyte membrane (-ARM) as a systemic indicator of the organism's adrenoreactivity. To assess adrenoreactivity, a technique is used based on a quantitative assessment of the degree of inhibition of hypoosmotic hemolysis of erythrocytes in vitro in the presence of the beta-blocker propranolol. The article presents data on the comparison of spectrophoto- and colorimetric determination of erythrocyte membrane beta-adrenoreactivity based on the registration of erythrocyte hemolysis with digital signal processing. A smartphone was used to register the images of the analyzed samples. Photography was carried out in a special box under standard lighting conditions. The chromaticity of the obtained images was evaluated using the Photoshop program within the RGB color model intended for computer color rendering. The obtained RGB values were used for quantitative determinations. The study was performed on 20 blood samples of patients suffering from bronchial asthma. The discrepancy between the results of determining -ARM using the colorimetric and spetrophotometric methods was no more than 5.6%, which indicates the possibility of replacing the spectrophotometer with image registration in digital format using software.

Five-year dynamics adrenergic reactivity of erythrocytes after radio-frequency sympathic denervation of renal arteries in patients with resistant arterial hypertension

To study the initial state of adrenergic reactivity and the five-year dynamics of the beta-adrenergic reactivity index of erythrocyte membranes and the manifestation of the antihypertensive effect of the procedure for radiofrequency destruction of sympathetic structures of the renal artery in patients with resistant arterial hypertension. The analysis included 42 patients with resistant arterial hypertension (RH). The renal denervation (RD) procedure of the kidneys was performed by endovascular bilateral transcatheter radiofrequency ablation of the renal arteries. The study of 24-hour blood pressure monitoring (BPM) and the determination of β-adrenoreactivity of erythrocytes (β-ARM) by changes in the osmoresistance of erythrocyte membranes were performed initially, 1 week, 6 months, 1, 2, 3 and 5 years after RD. Patients retrospectively, at a follow-up period of 6 months after RD, were divided into responders (decrease in blood pressure by 10 or more mm Hg) and non-responders (decrease in blood pressure less than 10 mm Hg). 6 months after the RD, the number of responders was 28 people (66.7%), after 5 years - 31 people (73.8%). At the time of inclusion in the study, the median β-ARM in the group of non-responders was not significantly higher than in the group of responders. After 6 months after the RD procedure, the β-ARM indicator in the non-responder group was significantly lower than in the responder group (p = 0.043). With further follow-up in the group of responders, an increase in the median β-ARM was noted, which reached significant differences relative to the baseline values in the group at follow-up periods of 1 year (p = 0.036) and 5 years (p = 0.004) after RD. The change in the β-ARM indicator in the non-responder group was wavy in nature, the changes did not reach the significance criteria. Renal denervation in 73.8% of cases is accompanied by a stable antihypertensive response for 5 years of observation and an increase in β-ARM, which may indicate the implementation of compensatory mechanisms in conditions of increasing activity of the sympathoadrenal system in response to a decrease in blood pressure.

Beta-adrenoreactivity of erythrocyte membranes and expression of beta1-adrenergic receptors of cardiomyocytes in patients with heart failure with different left ventricular ejection fraction

Introduction. More and more studies demonstrate the importance of determining the beta-adrenergic reactivity of erythrocyte membranes (beta-ARM) for predicting the severity of cardiovascular diseases, including chronic heart failure. But the presence of general patterns between the change in beta-ARM and the expression of beta1adrenergic receptors on the membranes of cardiomyocytes, depending on the left ventricular ejection fraction (LVEF) remains questionable.Aim: To evaluate beta-ARM and expression of beta1-adrenergic receptors of cardiomyocytes in groups of patients with heart failure with preserved (≥ 50%) and reduced (< 50%) LV EF.Materials and methods. The study included 100 patients with chronic heart failure of ischemic origin. Groups of 79 patients with LVEF ≥ 50% and 21 patients with LVEF < 50% were formed. The levels of epinephrine and norepinephrine in blood plasma and the expression of beta1-adrenergic receptors in myocardial samples were assessed using enzyme immunoassay. Beta-ARM was determined in whole blood by assessing the inhibition of hemolysis of erythrocytes placed in a hypoosmotic medium in the presence of a selective beta-blocker.Results. In the group with LV EF < 50%, beta-ARM was increased (p = 0.037), amounting to 31.9% (23.2; 40.1), compared with the group with LVEF ≥ 50%, where beta-ARM was 21.4% (15.0; 31.7). At the same time, in patients with LV EF < 50%, the expression of beta1-AR on cardiomyocyte membranes was significantly lower than in the other group (p = 0.037): 2.7 (2.1; 3.0) ng/mg and 3.1 (2.4; 3.9) ng/mg total protein, respectively. However, plasma levels of epinephrine and noradrenaline were comparable in the study groups.Conclusion. Patients with heart failure with LVEF < 50% were characterized by increased beta-ARM and reduced expression of beta1-AR on cardiomyocyte membranes compared with the group with LVEF ≥ 50% with comparable levels of circulating catecholamines.

Efficacy of catheter treatment of atrial fibrillation in patients with myocarditis depending on the adrenoreaction of the body (a prospective single-center study)

Background. Worldwide, research continues into various factors that may influence the success of catheter treatment of atrial fibrillation. In this regard, the influence of the state of the sympathoadrenal system of the body has not been studied enough. Aims to evaluate the effectiveness of interventional treatment of atrial fibrillation (AF) in patients with and without myocarditis, depending on the level of beta-adrenergic responsiveness of the organism. Materials and methods. The study sample included 40 patients. Of these, 27 (67.5%) are men. The age in the sample was 49 (44; 55) years. The study included 25 (62.5%) patients with paroxysmal AF, 10 (25.0%) with persistent and 5 (12.5%) with long-term persistent. All patients underwent surgical treatment of AF using radiofrequency (RFA) or cryoablation (CBA). Endomyocardial biopsy was performed in 18 patients to verify the diagnosis. Beta-adrenergic responsiveness (beta-ARM) was assessed in dynamics 3 days after surgery, 3 months and 12 months. The follow-up period for patients was 12 months. Results. All patients underwent surgical treatment of AF, in 7 cases (17.5%) CBA of the pulmonary veins was performed, in 33 (82.5%) cases RFA was performed. According to the biopsy results, signs of myocarditis were detected in 9 patients (22.5%). Focal myocarditis was found in 7 patients, diffuse in 2. The effectiveness of catheter treatment in general was 72.5%, for CBA 71.5%, for RFA 73.5%. Beta-ARM before ablation was 19.16% [12.46; 27.46], 3 days after ablation 24.43% [15.38; 33.65], after 3 months was 20.27% [9.90; 27.71], in 4 patients after 12 months, beta-ARM was 32.5% [20.0; 43.2]. The dynamics and influence of beta-ARM on the effectiveness of interventional treatment of AF in patients with early and late relapses, the presence of myocarditis was assessed. Conclusions. The results obtained showed no effect of the level of beta-ARM on the effectiveness of RFA and CBA in patients with and without myocarditis. Beta-ARM showed no association with the development of early arrhythmia recurrences after ablation. No statistically significant differences were found when comparing beta-ARM levels in patients with and without diagnosed myocarditis.

Chronic adrenergic stress and generation of myeloid-derived suppressor cells: Implications for cancer immunotherapy in dogs.

Recent studies have highlighted a key role played by the sympathetic nervous system (SNS) and adrenergic stress in mediating immune suppression associated with chronic inflammation in cancer and other diseases. The connection between chronic SNS activation, adrenergic stress and immune suppression is linked in part to the ability of catecholamines to stimulate the bone marrow release and differentiation of myeloid-derived suppressor cells (MDSC). Rodent model studies have revealed an important role for β-adrenergic receptor signalling in suppression of cancer immunity in mice subjected to chronic stresses, including thermal stress. Importantly, therapeutic blockade of beta-adrenergic responses by drugs such as propranolol can partially reverse the generation and differentiation of MDSC, and partly restore tumour immunity. Clinical trials in both humans and dogs with cancer have demonstrated that propranolol blockade can improve responses to radiation therapy, cancer vaccines and immune checkpoint inhibitors. Thus, the SNS stress response has become an important new target to relieve immune suppression in cancer and other chronic inflammatory conditions.

Abstract 13146: Cardioprotective Effects of Mtss1 Reduction in Dilated Cardiomyopathy

Introduction: MTSS1 is an I-BAR protein that interacts with the actin cytoskeleton and the cell membrane and is speculated to play a role in cell motility, tumor metastasis, and cardiogenesis. Enhancer variants that reduce the expression of MTSS1 in the human left ventricle have been associated with cardioprotective traits in genome-wide association studies. However, the effect of MTSS1 downregulation on the development of heart disease has not been studied in experimental models. Here we tested the hypothesis that reduction of MTSS1 protects against dilated cardiomyopathy (DCM) in vitro and in vivo. Methods: We used CRISPR-Cas9 to knock out MTSS1 in induced pluripotent stem cells (iPSCs) harboring pathogenic variants from patients with severe DCM. DCM iPSC lines with and without MTSS1 were then differentiated into cardiomyocytes and phenotyped in vitro. A DCM mouse model containing a TPM1 D230N transgene was crossed with a mouse model heterozygous for Mtss1 knockout. Progeny from this F1 cross were assessed for differences in cardiac structure and function via echocardiography. Results: MTSS1 deletion restored the beta-adrenergic response in DCM iPSC cardiomyocytes. In parallel, Mtss1 deletion partially rescued DCM-associated phenotypes including left ventricular dilation and reduced ejection fraction in mice. Conclusions: Our initial results suggest a causal link between MTSS1 reduction and cardioprotection in DCM. Inhibiting cardiac MTSS1 may hold therapeutic potential for DCM, though the cellular mechanisms through which MTSS1 affects cardiac phenotypes remain under investigation.

Features of erythrocyte membranes beta-adrenoreactivity in patients with resistant hypertension and type 2 diabetes mellitus

Introduction. Patients with resistant hypertension (RHTN) and type 2 diabetes mellitus (T2DM) are characterized by sympathetic hyperactivity. A promising method for the assessment is a measurement of erythrocyte membrane beta-adrenergic reactivity (β-ARM). However, little is known about β-ARM in patients with RHTN and T2DM.Purpose. To investigate the properties of β-ARM of erythrocytes in patients with RHTN and T2DM in relation to clinical, laboratory, and instrumental data.Material and Methods. The cross-sectional study comprised 38 patients with RHTN combined with T2DM with mean age of 62.1 ± 7 years (25 women (65.8%)), 24-hour systolic/diastolic blood pressure (24-BP) (SBP/DBP) of 160.3 ± 14.2/90.8 ± 10.5 mm Hg, and glycated hemoglobin (HbA1c) of 7.2 ± 1.4%. The comparison group comprised 24 patients with RHTN without T2DM, which did not significantly differ in sex and age. General clinical examinations, measurements 24-BP and office blood pressure, β-ARM, HbA1c, 24-hour urine, echocardiography, and 24-hour electrocardiography with the assessment of heart rate variability (HRV) with low-frequency (LF) and high-frequency (HF) components were performed in all patients.Research Results. In both groups, β-ARM was significantly higher than the normal value corresponding to 20 conventional units (CU): 45.9 ± 21.9 and 41.3 ± 18.9 for patients with RHTN+T2DM and RHTN without T2DM, respectively, p = 0.39. The incidence of increase in β-ARM was comparable: 82% in RHTN with T2DM patients and 88% in RHTN without T2DM patients, χ2 = 0.38, p = 0.537. The β-ARM values correlated with duration of hypertension (R = 0.31), SBP-24 variability (R = 0.36), LF (R = 0.60), and HF (R = –0.53)) values according to HRV, 24-hour urine volume (R = –0.32), left ventricular parameters (ejection fraction (R = 0.42), ventricular efficiency (R = –0.36), arterioventricular coupling (R = –0.40)), duration of T2DM (R = –0.45), and HbA1c level (R = –0.55).Conclusions. RHTN patients were characterized by a high frequency of β-ARM increase, whether or not T2DM was present, although a long and severe course of T2DM was associated with lower values of this indicator. According to the data from instrumental studies, β-ARM in patients with RHTN and T2DM was quantitatively related to the markers of sympathetic activity, which correlated with the duration of hypertension and parameters of renal and left ventricular functional status.

A UNIQUE CASE OF CONCURRENT EHLERS DANLOS SYNDROME (EDS) AND POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME (POTS) ASSOCIATED WITH ORTHOSTATIC HYPERTENSION RESPONDING TO IV FLUIDS

A UNIQUE CASE OF CONCURRENT EHLERS DANLOS SYNDROME (EDS) AND POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME (POTS) ASSOCIATED WITH ORTHOSTATIC HYPERTENSION RESPONDING TO IV FLUIDS

Long-Term Cultivation of Human Atrial Myocardium.

Organotypic culture of human ventricular myocardium is emerging in basic and translational cardiac research. However, few institutions have access to human ventricular tissue, whereas atrial tissue is more commonly available and important for studying atrial physiology. This study presents a method for long-term cultivation of beating human atrial myocardium. After written informed consent, tissues from the right-atrial appendage were obtained from patients with sinus rhythm undergoing open heart surgery with cardiopulmonary bypass. Trabeculae (pectinate muscles) prepared from the samples were installed into cultivation chambers at 37°C with a diastolic preload of 500 μN. After 2 days with 0.5 Hz pacing, stimulation frequency was set to 1 Hz. Contractile force was monitored continuously. Beta-adrenergic response, refractory period (RP) and maximum captured frequency (fmax) were assessed periodically. After cultivation, viability and electromechanical function were investigated, as well as the expression of several genes important for intracellular Ca2+ cycling and electrophysiology. Tissue microstructure was analyzed by confocal microscopy. We cultivated 19 constantly beating trabeculae from 8 patient samples for 12 days and 4 trabeculae from 3 specimen for 21 days. Functional parameters were compared directly after installation (0 d) with those after 12 d in culture. Contraction force was 384 ± 69 μN at 0 d and 255 ± 90 μN at 12 d (p = 0.8, n = 22), RP 480 ± 97 ms and 408 ± 78 ms (p = 0.3, n = 9), fmax 3.0 ± 0.5 Hz and 3.8 ± 0.5 Hz (p = 0.18, n = 9), respectively. Application of 100 nM isoprenaline to 11 trabeculae at 7 d increased contraction force from 168 ± 35 μN to 361 ± 60 μN (p < 0.01), fmax from 6.4 ± 0.6 Hz to 8.5 ± 0.4 Hz (p < 0.01) and lowered RP from 319 ± 22 ms to 223 ± 15 ms. CACNA1c (L-type Ca2+ channel subunit) and GJA1 (connexin-43) mRNA expressions were not significantly altered at 12 d vs 0 d, while ATP2A (SERCA) and KCNJ4 (Kir2.3) were downregulated, and KCNJ2 (Kir2.1) was upregulated. Simultaneous Ca2+ imaging and force recording showed preserved excitation-contraction coupling in cultivated trabeculae. Confocal microscopy indicated preserved cardiomyocyte structure, unaltered amounts of extracellular matrix and gap junctions. MTT assays confirmed viability at 12 d. We established a workflow that allows for stable cultivation and functional analysis of beating human atrial myocardium for up to 3 weeks. This method may lead to novel insights into the physiology and pathophysiology of human atrial myocardium.

Abstract 13122: STK25 Regulates the Cardiac PKA Pathway in Human Cardiomyocytes

Hypothesis: STK25 regulates cell survival, metabolism and cardiac function through phosphorylating PKA R1α and modulating PKA signaling pathway in human cardiomyocytes. Background: Dysregulation of cardiac kinases are related with many cardiovascular diseases including hypertrophy, remodeling and ischemia injury. STK25 is a stress response kinase that regulates cell survival through modulating several signaling pathways and is involved in the metabolism regulation. However, the direct substrates and mechanism of STK25 remain undefined. Methods: CRISPR-Cas9 was used to generate a homozygous knockout (KO) of STK25 in induced pluripotent stem cell (iPSC) which were then differentiated into cardiomyocytes (iPSC-CMs) and used for engineered human cardiac tissue generation. Role of STK25 in gene expression, cell proliferation/apoptosis, metabolism and cardiac function were characterized. STK25 was quantified in human left ventricular tissue from heart failure (HF) patients. Results: In iPSC-CMs, phospho-proteomic analysis identified PKA signaling as the most significantly upregulated pathway by STK25 deletion. PKA regulatory subunit I α (R1α) was identified as a downstream substrate of STK25 and validated by IP. Loss of STK25 resulted in elevated PKA kinase activity and decreased phosphorylation of PKA targets implicated in cardiac contractility and Ca2+ handling, such as cardiac myosin-binding protein C (cMyBPC), cardiac troponin (cTnT), ryanodine receptor-2 (RyR2) and L-type calcium channel (CaV1.2). Further mechanistic studies revealed that STK25 mediates PKA activity through phosphorylation of the R1α regulatory subunit at S77/83 sites, leading to inhibition of PKA kinase activity. In functional assays, STK25 modulated cell cycle progression, proliferation, hypoxia induced apoptosis, beta adrenergic response, and mitochondrial respiration in iPSC-CMs. We also detected significant increase in STK25 expression and PKA R1α phosphorylation in HF patients versus normal control, demonstrating STK25 altered regulation in heart diseases. Conclusions: STK25 kinase is a critical regulator of the PKA pathway in human cardiomyocytes modulating cell growth, metabolism and cardiac function and is aberrantly expressed in heart failure.

Abstract 11154: Cardioprotective Effects of Mtss1 Reduction Iin Dilated Cardiomyopathy

Introduction: MTSS1 is an I-BAR protein that interacts with the actin cytoskeleton and the cell membrane and is speculated to play a role in cell motility, tumor metastasis, and cardiogenesis. Enhancer variants that reduce the expression of MTSS1 in the human left ventricle have been associated with cardioprotective traits in genome-wide association studies. However, the effect of MTSS1 downregulation on the development of heart disease has not been studied in experimental models. Here we tested the hypothesis that reduction of MTSS1 protects against dilated cardiomyopathy (DCM) in vitro and in vivo . Methods: We used CRISPR-Cas9 to knock out MTSS1 in induced pluripotent stem cells (iPSCs) harboring pathogenic variants from patients with severe DCM. DCM iPSC lines with and without MTSS1 were then differentiated into cardiomyocytes and phenotyped in vitro . A DCM mouse model containing a TPM1 D230N transgene was crossed with a mouse model heterozygous for Mtss1 knockout. Progeny from this F1 cross were assessed for differences in cardiac structure and function via echocardiography. Results: MTSS1 deletion restored the beta-adrenergic response in DCM iPSC cardiomyocytes. In parallel, Mtss1 deletion partially rescued DCM-associated phenotypes including left ventricular dilation and reduced ejection fraction in mice. Conclusions: Our initial results suggest a causal link between MTSS1 reduction and cardioprotection in DCM. Inhibiting cardiac MTSS1 may hold therapeutic potential for DCM, though the cellular mechanisms through which MTSS1 affects cardiac phenotypes remain under investigation.

Attenuated beta-adrenergic response to stress and increased anticipation and perception of social threat in women high on perceived criticism

A large amount of literature has demonstrated that Perceived Criticism (PC)—that is, how critical a person believes a given relative is of him or her—is associated with negative clinical outcomes in a broad range of psychiatric disorders (e.g., relapse or recurrence of symptoms). A possible mechanism behind the predictive value of PC might be its association with the stress regulation process. This is the first study to investigate differences in the psychophysiological response to a social stress task in young women (mean age = 21.66, SD = 4.33) with high (n = 40) and low (n = 39) PC. The physiological response was investigated by measuring two markers of sympathetic activity mediated by acetylcholine (skin conductance levels; SCL) and adrenaline (pre-ejection period; PEP) levels, respectively, and one marker of the vagally-mediated parasympathetic system (heart rate variability; HRV). Moreover, we investigated the anticipation and perception of social threat, in the form of criticism, during the stressor. No differences in HRV and SCL were observed. However, individuals high in PC mobilized fewer cardiovascular resources to deal with the stressor, reflected in an attenuated beta-adrenergic response (i.e., lower PEP response). Women high in PC also expected and perceived more criticism during the stress task. Together, our results indicate that women high in PC make heightened social threat anticipation and interpretations, and they tend to engage in less active coping when exposed to socially evaluated stressful events. Our findings indicate that PC is associated with underlying stress-related psychobiological vulnerabilities that may contribute to its association with negative clinical outcomes.

Thiamine increases resident endoglin positive cardiac progenitor cells and atrial contractile force in humans: A randomised controlled trial

BackgroundThe heart has an intrinsic ability to regenerate, orchestrated by progenitor or stem cells. However, the relative complexity of non-resident cardiac progenitor cell (CPC) therapy makes modulation of resident CPCs a more attractive treatment target. Thiamine analogues improve resident CPC function in pre-clinical models. In this double blinded randomised controlled trial (identifier: ACTRN12614000755639), we examined whether thiamine would improve CPC function in humans. Methods and resultsHigh dose oral thiamine (one gram twice daily) or matching placebo was administered 3–5 days prior to coronary artery bypass surgery (CABG). Right atrial appendages were collected at the time of CABG, and CPCs isolated. There was no difference in the primary outcome (proliferation ability of CPCs) between treatment groups. Older age was not associated with decreased proliferation ability. In exploratory analyses, isolated CPCs in the thiamine group showed an increase in the proportion of CD34−/CD105+ (endoglin) cells, but no difference in CD34−/CD90+ or CD34+ cells. Thiamine increased maximum force developed by isolated trabeculae, with no difference in relaxation time or beta-adrenergic responsiveness. ConclusionThiamine does not improve proliferation ability of CPC in patients undergoing CABG, but increases the proportion of CD34−/CD105+ cells. Having not met its primary endpoint, this study provides the impetus to re-examine CPC biology prior to any clinical outcome-based trial examining potential beneficial cardiovascular effects of thiamine.

Safety and Efficacy of Veverimer in Acidotic Patients With CKD and Heart Failure

Safety and Efficacy of Veverimer in Acidotic Patients With CKD and Heart Failure

Alterations in Biochemical Markers of Kidney Function of Thyroid Disorders at Vidharbha Region, India

Background: The thyroid gland is a major endocrine gland in the body that is located in the front of the neck. Thyroid disorders cause problems on kidney function in a variety of ways. Hyperthyroidism causes an increase in both RBF and GFR. The expression of cardiac beta-adrenergic receptors may be influenced by thyroid hormones. The increased catecholamine sensitivity of beta adrenergic coupled cardiac responses in hyperthyroid patients may be due to the increased number of receptors. ROS may be one of the main causes of kidney failure in thyroid disorders, although this needs to be confirmed in the lab.&#x0D; Aim: The aim of this research was to look at the effects of thyroid disorders on kidney function and oxidative stress markers, as well as the relationship between them.&#x0D; Materials and Methods: After visiting Shalinitai Meghe hospital in Nagpur for a health check-up, a total of 350 people were chosen for the research. This was the place where the five groups were held. Subclinical Hypothyroidism: 70 subjects, Overt Hypothyroidism: 70 subjects, Subclinical Hyperthyroidism: 70 subjects, Overt Hyperthyroidism: 70 subjects. There are 70 patients in each household. Specific biochemical methods were used to quantify biochemical parameters such as T3, T4, TSH, Urea, Creatinine, and Cys C. Assay of Superoxide dismutase by Marklund and Marklund method&#x0D; ResultS: In our work, we discovered a significant positive correlation between serum creatinine and TSH in hypothyroidism and hyperthyroidism, and a significant negative correlation between serum Cystatin C and TSH in hypothyroidism and hyperthyroidism. TSH was linked to oxidative stress markers as well. When the oxidative stress markers MDA and SOD were statistically analysed, they were found to be highly associated with markers of kidney function.&#x0D; Conclusion:When the incidence of chronic kidney disease rises, all instances of hypothyroidism and hyperthyroidism should be regularly tested for worsening kidney functions, and since the study indicates that oxidative stress plays a role in nephropathy, current thyroid disorders treatment methods should include oxidative stress, which will aid clinicians in better managing kidney dysfunction.

Reduction of P62/SQSTM1 on Calcium Handling in Stressed Myocytes

Introduction Cytosolic protein, p62/SQSTM1, regulates the protein turnover rate, and it interacts with various stress signaling proteins in cells. Accumulations of p62/SQSTM1 have been reported in hearts with cardiomyopathy. We recently reported that p62/SQSTM1 protein deletions reduced beta-adrenergic response in myocytes and improved chronic ischemia-induced Calcium (Ca) defect. Here, we studied acute and chronic stress-induced Ca handling in myocytes genetically suppressed p62/SQSTM1 protein. Methods Myocytes (n=3 per group) isolated from Wild-type (WT), and p62/SQSTM1+/- (p62 HET) at Base, 5 days, and 10 days after Isoproterenol (ISO; beta-agonist) injections (150 mg/kg). We measured myocytes contractility (Fraction shortening of sarcomeres), systolic Ca release (CaT), SR Ca contents (CaffT), and Fractional Ca release, (CaT/CaffT) in field-stimulated single myocytes. Myocytes loaded with fluorescent Ca indicators (Fura-2AM; cytosolic Ca loading). Heart tissues in each group were processed for western blot (n=3 per group). Results The baseline myocytes contractility and Ca regulation were not different among the groups. P62 HET myocytes significantly increased contractility and fractional Ca release (the function of SR, F/F0; WT base, 0.58±0.07, WT ISO, 0.84±0.01, p62 HET ISO, 0.79±0.04) after acute ISO stimulation (1 uM, p<0.05), similar to WT myocytes. Interestingly, p62 HET myocytes preserved SR Ca contents, whereas WT myocytes increased SR Ca contents. Chronic ischemia-induced p62 HET myocytes improved fractional Ca release; however, both systolic Ca release (F/F0; WT base, 0.24±0.03, WT ISO 10days, 0.29±0.06, p62 HET ISO 10 days, 0.17±0.02) and SR Ca contents (F/F0; WT base, 0.43±0.05, WT ISO, 0.49±0.10, p62 HET ISO, 0.33±0.04) were proportionally reduced (p<0.05). Conclusion Taken together, suppression of p62/SQSTM1 protein restores stress-induced Ca dysregulation in myocytes. p62/SQSTM1 protein may directly contribute to systolic Ca release via beta-adrenergic signaling.

Indirect autonomic nervous system activity assessment in patients with myocardial infarction

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Abnormalities in the cardiac sympathetic nervous system have been documented in myocardial infarction (MI) and have been directly implicated in pathogenesis and progression of MI. Assessment of the autonomic nervous system activity in acute stage of MI allowed us to identify groups of high-risk patients. Purpose To investigate the sympathetic nervous system activity in patients with MI by assessing the condition of beta-adrenergic reactivity of erythrocytes. To analyze ADRB1 Arg389Gly associations with the state of beta-adrenergic reactivity of erythrocytes in patients with MI. Methods During the study period, 62 patients were enrolled. The patients were divided into 2 groups. The first group consisted of 11 patients (nine women and two men, median age of 54.0 [49.0;61.0] years) with normal beta-adrenergic reactivity of erythrocytes, the second group consisted of 51 patients (40 women and 11 man, median age of 61.0 [48.0;72.0] years) with abnormal beta-adrenergic reactivity of erythrocytes. The research of beta-adrenergic reactivity of erythrocytes was conducted by analysis of changing erythrocyte osmoresistance under the influence of beta blocker in the first 6 hours from the onset of the heart attack. The genetic research was conducted by PСR method in real time. Results Groups of patients were comparable in main clinical indicators (anamnesis of ischemic heart disease and chronic heart failure, frequency of beta blockers administration before and during of MI, electrocardiography features: elevation of ST-segment, Q-wave and etc.). The second group presented with a higher occurrence of acute left ventricular failure (33.3% vs 0%, p = 0.026) and arterial hypertension (90.2% vs 63.6%, p = 0.044). Parameters of myocardial damage were significantly higher in the second group than the first group. Primarily, this manifested in the presence of a greater number of hypokinesis zones on echocardiography (p = 0.015). In addition, patients of the second group had a lower ejection fraction according to echocardiography (51.0 [46.5;59.0]% vs 58.0 [52.0;63.0]%, p = 0.042). Levels of blood necrosis biomarkers were significantly higher in the second group, e.g. Troponin I (24.1 [9.9;68.0] ng/ml vs 1.3 [0.2;1.8] ng/ml, p = 0.001). At the same time statistically significant distinctions of the severity of coronary atherosclerosis in groups were not revealed. The analysis of ADRB1 Arg389Gly demonstrated association of CC-genotype with abnormal beta-adrenergic reactivity of erythrocytes [OR 5.9, 95% СI 1.16-30.25, p = 0.043]. Conclusion Patients with an abnormal beta-adrenergic reactivity were characterized by a greater volume of damage to the heart muscle. Moreover, association of CC-genotype of gene ADRB1 Arg389Gly with abnormal beta-adrenergic reactivity of erythrocytes was identified.

Association of beta-adrenergic reactivity index of erythrocyte membranes in myocardial infarction with genetic features of the beta-adrenoreceptor apparatus

Objective: To study the association of beta-adrenergic reactivity index of erythrocyte membranes with polymorphisms of the beta-1-adrenergic receptor gene ADRB1 (Ser49Gly and Arg389Gly).Material and methods: the study included 62 patients with myocardial infarction (MI) — 49 men (median age of 58.0 (47.5; 64.5) years) and 13 women (median age of 76.0 (61.5; 81.0) years). All patients underwent analysis of beta-adrenoreactivity of erythrocyte membranes using the BETA-ARM AGAT reagent kit within the first 6 hours from the onset of MI. The patients were divided into 2 groups depending on the value of the beta-adrenergic reactivity index (β-ARM). The first group (n = 11) included patients with a normal P-ARM level (from 2 to 20 conventional units). The second group (n = 51) consisted of patients with increased values of β-ARM (more than 20 standard units). Genetic analysis for the determination of ADRB1 gene polymorphisms (Ser49Gly and Arg389Gly) was carried out by isolating DNA from peripheral blood leukocytes (Wizard Genomic DNA Purification Kit) with PCR amplification and further electrophoretic detection. Statistical processing of the obtained data was carried out using Statistica 10 software and the demo version of IBM SPSS Statistics 20.0.Results: patients with elevated β-APM values were characterized by higher levels of myocardial necrosis markers in the blood (CPK, CPK-MB, and troponin I) in acute myocardial infarction than for patients of the first group (p = 0.009, p = 0.032 and p = 0.001, respectively). In addition, the second group of patients was characterized by a more frequent development of acute left ventricular failure (33.3%, p = 0.026), as well as a history of arterial hypertension before the development of index MI (90.2%, p = 0.044). With regard to the Arg389Gly polymorphism, significant differences were found among patients with normal and increased P-APM values in the acute period of MI. Thus, the second group of patients consisted mainly of carriers of the 1165CC genotype of the ADRB1 gene (n = 29, 56.9%, p = 0.043). The carriage of the 1165G allele was much more often observed among patients of the first group (81.8%; OR = 5.93; CI 1.16-30.25; p = 0.043).Conclusion: an association of the 1165CC genotype of the Arg389Gly polymorphism of the ADRB1 gene with increased β-APM values in acute MI was established. The detected associations may indicate a possible genetic predisposition to SAS hyperactivation, and also indicate the need for further study of polymorphisms and the level of expression of the ADRB1 gene in patients with high individual values of β-APM established in the acute period of MI.

Effects of selective TNFR1 inhibition or TNFR2 stimulation, compared to non-selective TNF inhibition, on (neuro)inflammation and behavior after myocardial infarction in male mice

BackgroundMyocardial infarction (MI) coinciding with depression worsens prognosis. Although Tumor Necrosis Factor alpha (TNF) is recognized to play a role in both conditions, the therapeutic potential of TNF inhibition is disappointing. TNF activates two receptors, TNFR1 and TNFR2, associated with opposite effects. Therefore, anti-inflammatory treatment with specific TNF receptor interference was compared to non-specific TNF inhibition regarding effects on heart, (neuro)inflammation, brain and behavior in mice with MI. MethodsMale C57BL/6 mice were subjected to MI or sham surgery. One hour later, MI mice were randomized to either non-specific TNF inhibition by Enbrel, specific TNFR1 antagonist-, or specific TNFR2 agonist treatment until the end of the protocol. Control sham and MI mice received saline. Behavioral evaluation was obtained day 10–14 after surgery. Eighteen days post-surgery, cardiac function was measured and mice were sacrificed. Blood and tissue samples were collected for analyses of (neuro)inflammation. ResultsMI mice displayed left ventricular dysfunction, without heart failure, (neuro) inflammation or depressive-like behavior. Both receptor-specific interventions, but not Enbrel, doubled early post-MI mortality. TNFR2 agonist treatment improved left ventricular function and caused hyper-ramification of microglia, with no effect on depressive-like behavior. In contrast, TNFR1 antagonist treatment was associated with enhanced (neuro)inflammation: more plasma eosinophils and monocytes; increased plasma Lcn2 and hippocampal microglia and astrocyte activation. Moreover, increased baseline heart rate, with reduced beta-adrenergic responsiveness indicated sympathetic activation, and coincided with reduced exploratory behavior in the open field. Enbrel did not affect neuroinflammation nor behavior. ConclusionEarly receptor interventions, but not non-specific TNF inhibition, increased mortality. Apart from this undesired effect, the general beneficial profile after TNFR2 stimulation, rather than the unfavourable effects of TNFR1 inhibition, would render TNFR2 stimulation preferable over non-specific TNF inhibition in MI with comorbid depression. However, follow-up studies regarding optimal timing and dosing are needed.

A CASE OF THYROTOXIC PERIODIC PARALYSIS IN AN AFRICAN AMERICAN MALE REQUIRING MECHANICAL VENTILATION AND HEMODIALYSIS

SESSION TITLE: Medical Student/Resident Critical Care SESSION TYPE: Med Student/Res Case Report PRESENTED ON: October 18-21, 2020 INTRODUCTION: Thyrotoxic periodic paralysis (TPP) represents a rare, acquired form of hypokalemic periodic paralysis characterized by acute onset muscle weakness and hypokalemia. We report a severe presentation requiring mechanical ventilation and hemodialysis (HD). CASE PRESENTATION: A 25 year old African American male presented with bilateral lower extremity weakness and hypokalemia at 1.6 mmol/L with characteristic hypokalemic ECG changes. After receiving 40 mEq IV potassium chloride, his hypokalemia worsened to 1.1. Given acute progression of ascending paralysis to complete paraplegia, 3/5 strength in upper extremities and concern for impending diaphragmatic weakness, he was intubated. Despite an additional 170 mEq of potassium, his repeat K+ was 1.5 with progressive EKG changes. He also had a metabolic acidosis with pH of 7.208 and a lactic acid of 8.7. Given refractory hypokalemia and concern that bicarbonate therapy for acidosis would worsen the hypokalemia, the patient was initiated on HD with a high potassium bath. The team confirmed suspicion of TPP upon return of TSH level <0.015 mU/L and administered 3 doses of 1 mg IV Propranolol during which he exhibited spontaneous extremity movements. Serial labs then revealed a rebound hyperkalemia up to 7.4 mmol/L with characteristic hyperkalemic ECG changes. He received usual stabilizing treatments and a second session of emergent HD to correct the up trending hyperkalemia. Diagnosis and recovery was confirmed after stable potassium levels, resolved acidosis, complete recovery of his neurological exam and notably elevated T4 and T3 levels. He was extubated without complication and discharged home on Propylthiouracil with instructions to follow-up with endocrinology for further evaluation of his hyperthyroidism. DISCUSSION: As compared to prior published cases of TPP most often amongst Asian males, management of this African American patient differed with the use of mechanical ventilation for airway protection due to rapidly progressive ascending paralysis and down trending negative inspiratory forces and vital capacities. It also necessitated the use of hemodialysis to correct both the refractory hypokalemia and concomitant acidosis. It is believed that a thyrotoxic-mediated beta-adrenergic response drives potassium into cells hyperpolarizing muscle fibers, causes an extracellular shift of hydrogen and increases conversion of pyruvate to lactate resulting in acidosis. The concern with addressing this with a bicarbonate drip was that a secondary alkalosis would further intracellularly shift potassium. Fortunately, already having a HD catheter in place allowed for more rapid treatment of the severe rebound hyperkalemia. CONCLUSIONS: Initial suspicion of TPP on the differential for ascending paralysis and earlier use of IV propranolol can prevent progression of paralysis, rebound hyperkalemia, lactic acidosis and life-threatening cardiac arrhythmias. Reference #1: Younis AA. Thyrotoxic Periodic Paralysis as a Presentation of Thyrotoxicosis: A Case Report and review of the literature. Mediterr J Rheumatol. 2018;29(1):46–48. Reference #2: Wong P. Hypokalemic thyrotoxic periodic paralysis: a case series. CJEM. 2003;5(5):353–355. Reference #3: Tassone H, Moulin A, Henderson SO. The pitfalls of potassium replacement in thyrotoxic periodic paralysis: a case report and review of the literature. J Emerg Med. 2004;26(2):157–161. DISCLOSURES: No relevant relationships by Firth Bowden, source=Web Response No relevant relationships by Uday Gulati, source=Web Response No relevant relationships by Asma Qayyum, source=Web Response No relevant relationships by samson zarbiv, source=Admin input