Characterization of lymphocyte beta-adrenoceptor activity and Gs-protein in patients with rheumatic heart valvular disease

Predicting ICU Mortality in Rheumatic Heart Disease: Comparison of XGBoost and Logistic Regression

Background

Rheumatic heart disease (RHD) accounts for a large proportion of Intensive Care Unit (ICU) deaths. Early prediction of RHD can help with timely and appropriate treatment to improve survival outcomes, and the XGBoost machine learning technology can be used to identify predictive factors; however, its use has been limited in the past. We compared the performance of logistic regression and XGBoost in predicting hospital mortality among patients with RHD from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database.

Methods

The patients with RHD in the MIMIC-IV database were divided into two groups retrospectively according to the availability of data and its clinical significance based on whether they survived or died. Backward stepwise regression was used to analyze the independent factors influencing patients with RHD, and to compare the differences between the two groups. The XGBoost algorithm and logistic regression were used to establish two prediction models, and the areas under the receiver operating characteristic curves (AUCs) and decision-curve analysis (DCA) were used to test and compare the models. Finally, DCA and the clinical impact curve (CIC) were used to validate the model.

Results

Data on 1,634 patients with RHD were analyzed, comprising 207 who died during hospitalization and 1,427 survived. According to estimated results for the two models using AUCs [0.838 (95% confidence interval = 0.786–0.891) and 0.815 (95% confidence interval = 0.765–0.865)] and DCA, the logistic regression model performed better. DCA and CIC verified that the logistic regression model had convincing predictive value.

Conclusions

We used logistic regression analysis to establish a more meaningful prediction model for the final outcome of patients with RHD. This model might be clinically useful for patients with RHD and help clinicians to provide detailed treatments and precise management.

Adrenergic modulation of immune cells: an update

Sympathoadrenergic pathways are crucial to the communication between the nervous system and the immune system. The present review addresses emerging issues in the adrenergic modulation of immune cells, including: the specific pattern of adrenoceptor expression on immune cells and their role and changes upon cell differentiation and activation; the production and utilization of noradrenaline and adrenaline by immune cells themselves; the dysregulation of adrenergic immune mechanisms in disease and their potential as novel therapeutic targets. A wide array of sympathoadrenergic therapeutics is currently used for non-immune indications, and could represent an attractive source of non-conventional immunomodulating agents.

Beta adrenoceptor density in patients with left-sided valvular regurgitation

Aortic regurgitation differs from mitral regurgitation in that it is a result of combined volume and pressure overload, while the latter represents an almost pure volume overload. In this study, we tested the possibility that these two forms of left ventricular volume overload exert different effects on beta-adrenoceptor density. Lymphocyte (n = 33) and myocardial (n = 22) beta-adrenoceptor densities were evaluated by [125I]-iodocyanopindolol binding in volume-overload patients with left heart valvular disease, compared with 31 healthy donor blood and 15 donor heart controls, made available as a result of failing to get matching recipient. The total lymphocyte (LC) beta-adrenoceptor density decreased from 43.4 +/- 5.5 fmol mg-1 protein in controls to 9.2 +/- 2.7 fmol (P < 0.001) in heart valvular patients. In the myocardial controls, the left ventricular (LV)-receptor density was 126.7 +/- 19.5 fmol; right ventricular (RV), 123.1 +/- 14.6 fmol; left atrial (LA), 81.6 +/- 10.5 fmol; and right atrial (RA), 108.1 +/- 14.5 fmol mg-1 protein. Compared to this group, the total LV-receptor density of the patients decreased by 63%, RV by 54%, LA by 31% and RA by 34%. The decrease in receptor density exhibited a positive correlation with increasing ejection fractions in both the left (r = 0.38) and right (r = 0.44) ventricles, indicating that the former was dependent on the extent of the disease. These changes were accompanied by a 44% increase in plasma epinephrine, 13% in norepinephrine and a 27% decrease in dopamine levels. Based on the predominant left ventricular volume overload classified as aortic regurgitation (AVR), mitral regurgitation (MVR), and mixed aortic and mitral regurgitation (MOL), the attenuation in myocardial-receptor densities showed the following trend: MOL > AVR > AVR. The results show a global reduction in myocardial and LC beta-adrenoceptor density, which depends on the origin and the gravity of the LV volume overload.

Effects of different left ventricular load conditions on myocardial beta-adrenoceptor density in patients with rheumatic heart valvular disease

1. The possibility that different left ventricular load conditions may influence myocardial beta-adrenoceptor function in various ways was evaluated by determining the receptor density in all four chambers of 69 patients with rheumatic heart valvular disease. 2. The left ventricular beta-adrenoceptor density was reduced by 44% in patients with left ventricular pressure overload (LVP), 66% in left ventricular volume overload (LVV), 56% in mixed volume and pressure overload (MOL), and 60% in those with no left ventricular pressure overload (NOL). Similarly, the right ventricular receptor density decreased significantly by 46%, 54%, 43%, and 46%, left atrial by 15%, 29%, 14%, and 21%; and right atrial by 27%, 30%, 28%, and 12% in LVP, LVV, MOL, and NOL, respectively. Thus, the general trend in the decrease in receptor density was LVV > MOL = NOL > LVP. 3. Furthermore, the LVV patients with the largest decrease in receptor density in all four chambers, similarly exhibited the largest ejection fractions (EF) and left ventricular internal diastolic and systolic diameters. 4. The results show that left ventricular volume overload is a major cause of attenuation in myocardial beta-adrenoceptor density, compared to other forms of ventricular overload in heart valvular disease. 5. Since elevated EF in volume overload patients is an indication of the severity of the disease, the decrease in their myocardial receptor density may be a reflection of the degree of influence of the disease on their sympathetic activity.

Relationship between alterations in lymphocyte and myocardial beta-adrenoceptor density in patients with left heart valvular disease

1. We have evaluated the possibility that alterations in lymphocyte beta-adrenoceptor density may be related to changes in the myocardial population in left heart valvular diseases. Receptor density and their binding affinities were estimated using [125I]-iodocyanopindolol. 2. The lymphocyte (LC) beta-adrenoceptor density was 43.4 +/- 5.6 fmol/mg protein in the controls (n = 35) and 81% lower in heart valvular patients (n = 86). In myocardial controls (n = 18), the left ventricular (LV) receptor density was 167.2 +/- 29.8 fmol/mg protein, right ventricular (RV) density was 123.1 +/- 14.6 fmol/mg, left atrial (LA) density was 81.6 +/- 10.5 fmol/mg and right atrial (RA) 108.1 +/- 14.5 fmol/mg. Compared with this group, the receptor density of the study patients (n = 47) decreased by 67, 43, 24 and 32% in the LV, RV, LA and RA, respectively. The decrease in LC was twice that of the average total myocardial receptor density. 3. When patients were classified according to their left ventricular load conditions as having either left ventricular pressure overload (LVP), left ventricular volume overload, mixed lesions (MOL) and no left ventricular overload (mitral stenosis; NOL), the attenuation in LC receptor density reached statistical significance for all four groups, without showing significant difference between the individual groups. In contrast, the decrease in all chambers was predominantly due to volume overload. MOL and NOL exerted intermediate effects that were significant in the LV, while LVP did not contribute to the changes in the LA. 4. Accordingly, the reduction in peripheral beta-adrenoceptor density may reflect the extent to which particularly the volume overload exerts its influence on myocardial beta-adrenoceptors in left heart valvular patients.

Comparison of the effect of left ventricular volume and pressure overload on beta-adrenoceptor density in left heart valvular disease

The sympathetic responses in left heart valvular disease may depend on the ventricular load conditions. We proposed to evaluate this possibility by comparing the effects of left ventricular pressure (LVP) and volume (LVV) overload on beta-adrenoceptor density and ligand binding affinity in lymphocytes and in the four myocardial chambers in rheumatic heart valvular patients. Receptor activity was determined by radioligand binding using [125I]iodocyanopindolol. In the lymphocytes (n = 45), the beta-adrenoceptor density was reduced by 88% (P < 0.001) in LVP patients (n = 15) and 79% (P < 0.001) in LVV patients (n = 30) compared with 23 controls. In the myocardium, the receptor density of the LVP (n = 12) was attenuated by 55% (P < 0.05) in the left ventricle, 42% in the right ventricle, 13% in the left atrium, and 37% in the right atrium, while in LVV patients (n = 22) it decreased by 73% (P < 0.01) in the left ventricle, 62% (P < 0.05) in the right ventricle, 30% in the left atrium, and 34% in the right atrium compared with 15 controls. Thus, the reduction in density was greatest in lymphocytes and least in the atria in both groups. The decrease in ventricular density of the LVV group was similar to the reduction in the lymphocytes and two-fold higher than in the atrial density. These alterations were significantly greater for the LVV than for the LVP group. The Kd for the myocardial receptor binding to [125I]iodocyanopindolol was not significantly influenced in either group, but was lower in the lymphocytes. These findings suggest that in patients with left heart valvular disease, there is a significant attenuation in both peripheral and myocardial beta-adrenoceptor density. The decrease in receptor density is significantly greater in the left ventricular volume overload than in the left ventricular pressure overload patients.