Age and mean platelet volume-based nomogram for predicting the therapeutic efficacy of metoprolol in Chinese pediatric patients with vasovagal syncope.

BACKGROUND: Vasovagal syncope (VVS) is the most common type of orthostatic intolerance in children. We investigated whether platelet-related factors related to treatment efficacy in children suffering from VVS treated with metoprolol. METHODS: Metoprolol-treated VVS patients were recruited. The median duration of therapy was three months. Patients were followed and divided into two groups, treament-effective group and treatment-ineffective group. Logistic and least absolute shrinkage selection operator regressions were used to examine treatment outcome variables. Receiver-operating characteristic (ROC) curves, precision-recall (PR) curves, calibration plots, and decision curve analyses were used to evaluate the nomogram model. RESULTS: Among the 72 patients who complete the follow-up, treatment-effective group and treatment-ineffective group included 42 (58.3%) and 30 (41.7%) cases, respectively. The patients in the treatment-effective group exhibited higher mean platelet volume (MPV) [(11.0 ± 1.0) fl vs. (9.8 ± 1.0) fl, P < 0.01] and platelet distribution width [12.7% (12.3%, 14.3%) vs. 11.3% (10.2%, 12.2%), P < 0.01] than those in the treatment-ineffective group. The sex ratio was significantly different (P = 0.046). A fit model comprising age [odds ratio (OR) = 0.766, 95% confidence interval (CI) = 0.594-0.987] and MPV (OR = 5.613, 95% CI = 2.297-13.711) might predict therapeutic efficacy. The area under the curve of the ROC and PR curves was computed to be 0.85 and 0.9, respectively. The P value of the Hosmer-Lemeshow test was 0.27. The decision curve analysis confirmed that managing children with VVS based on the predictive model led to a net advantage ranging from 0.01 to 0.58. The nomogram is convenient for clinical applications. CONCLUSION: A novel nomogram based on age and MPV can predict the therapeutic benefits of metoprolol in children with VVS.

Endogenous sulfur dioxide deficiency as a driver of cardiomyocyte senescence through abolishing sulphenylation of STAT3 at cysteine 259.

OBJECTIVE: Cardiomyocyte senescence is an important contributor to cardiovascular diseases and can be induced by stressors including DNA damage, oxidative stress, mitochondrial dysfunction, epigenetic regulation, etc. However, the underlying mechanisms for the development of cardiomyocyte senescence remain largely unknown. Sulfur dioxide (SO2) is produced endogenously by aspartate aminotransferase 2 (AAT2) catalysis and plays an important regulatory role in the development of cardiovascular diseases. The present study aimed to explore the effect of endogenous SO2 on cardiomyocyte senescence and the underlying molecular mechanisms. APPROACH AND RESULTS: We interestingly found a substantial reduction in the expression of AAT2 in the heart of aged mice in comparison to young mice. AAT2-knockdowned cardiomyocytes exhibited reduced SO2 content, elevated expression levels of Tp53, p21Cip/Waf, and p16INk4a, enhanced SA-ß-Gal activity, and elevated level of γ-H2AX foci. Notably, supplementation with a SO2 donor ameliorated the spontaneous senescence phenotype and DNA damage caused by AAT2 deficiency in cardiomyocytes. Mechanistically, AAT2 deficiency suppressed the sulphenylation of signal transducer and activator of transcription 3 (STAT3) facilitated its nuclear translocation and DNA-binding capacity. Conversely, a mutation in the cysteine (Cys) 259 residue of STAT3 blocked SO2-induced STAT3 sulphenylation and subsequently prevented the inhibitory effect of SO2 on STAT3-DNA-binding capacity, DNA damage, and cardiomyocyte senescence. Additionally, cardiomyocyte (cm)-specific AAT2 knockout (AAT2cmKO) mice exhibited a deterioration in cardiac function, cardiomegaly, and cardiac aging, whereas supplementation with SO2 donors mitigated the cardiac aging and remodeling phenotypes in AAT2cmKO mice. CONCLUSION: Downregulation of the endogenous SO2/AAT2 pathway is a crucial pathogenic mechanism underlying cardiomyocyte senescence. Endogenous SO2 modifies STAT3 by sulphenylating Cys259, leading to the inhibition of DNA damage and the protection against cardiomyocyte senescence.

Establishment and validation of a multivariate predictive model for the efficacy of oral rehydration salts in children with postural tachycardia syndrome.

BACKGROUND: The therapeutic effectiveness of the empirical and unselected use of oral rehydration salts (ORS) on postural tachycardia syndrome (POTS) is not satisfactory in children. Therefore, looking for suitable predictors of the therapeutic effects of ORS before treatment is extremely necessary to implement individualised treatment for paediatric patients with POTS. METHODS: A retrospective case-control analysis of 130 patients (aged 5-18 years) who suffered from POTS with a 3-month treatment of ORS was conducted. A nomogram model was developed in the training set (n = 87) to predict the therapeutic response to ORS. Univariate analysis and logistic regression were applied to select the most useful predictors. ROC curves were applied to evaluate the discriminative performance of the nomogram model. The nomogram was then evaluated by calibration curves and the Hosmer-Lemeshow (H-L) test. The results were further validated using 1000 bootstrap resamples. External validation was performed in an independent validation set (n = 43). FINDINGS: Among the ten variables with significant differences between the responders and non-responders in univariate analysis, five variables were found to be independently associated factors for ORS therapeutic efficacy among POTS children in the further logistic regression, including mean corpuscular haemoglobin concentration (MCHC), mean corpuscular volume (MCV), mean arterial pressure (MAP) at the first minute of the upright position, urine specific gravity (SG), and P-wave voltage peaking ratio (PWP). The nomogram model was established in the training set (AUC 0.926 [95% CI: 0.865-0.988], yielding a sensitivity of 87.8% and a specificity of 86.8%). The calibration curves showed good agreement between the prediction of the nomogram and actual observation in both the training and validation sets. The nomogram also effectively predicted the external validation set (sensitivity 82.1%, specificity 73.3%, and accuracy 79.1%). INTERPRETATION: We established a feasible and high-precision nomogram model to predict the efficacy of ORS, which would help implement individualised treatment for children with POTS. FUNDING: This study was supported by National High-Level Hospital Clinical Research Funding (Multi-centre Clinical Research Project of Peking University First Hospital) (2022CR59).

The diagnosis and treatment of pediatric clinical myocarditis in China: a multicenter retrospective study.

This study aims to examine the clinical characteristics and outcomes of clinical myocarditis in pediatric patients in China. This is a multicenter retrospective study. Children diagnosed with clinical myocarditis from 20 hospitals in China and admitted between January 1, 2015, and December 30, 2021, were enrolled. The clinical myocarditis was diagnosed based on the "Diagnostic Recommendation for Myocarditis in Children (Version 2018)". The clinical data were collected from their medical records. A total of 1210 patients were finally enrolled in this study. Among them, 45.6% had a history of respiratory tract infection. An abnormal electrocardiogram was observed in 74.2% of patients. Echocardiography revealed that 32.3% of patients had a left ventricular ejection fraction of less than 50%. Cardiac MRI was performed in 4.9% of children with clinical myocarditis, of which 61% showed localized or diffuse hypersignal on T2-weighted images. Serum levels of cardiac troponin I (cTnI), creatine kinase-MB (CK-MB), and N-terminal B-type natriuretic peptide (NT-proBNP) were higher in patients with fulminant myocarditis than in patients with myocarditis, making them potential risk factors for fulminant myocarditis. Following active treatment, 12.1% of patients were cured, and 79.1% were discharged with improvement. CONCLUSION: Clinical myocarditis in children often presents with symptoms outside the cardiovascular system. CK-MB, cTnI, and NT-proBNP are important indicators for assessing clinical myocarditis. The electrocardiogram and echocardiogram findings in children with clinical myocarditis exhibit significant variability but lack specificity. Cardiac MRI can be a useful tool for screening clinical myocarditis. Most children with clinical myocarditis have a favorable prognosis. WHAT IS KNOWN: • Pediatric myocarditis presents complex clinical manifestations and exhibits varying degrees of severity. Children with mild myocarditis generally have a favorable prognosis, while a small number of children with critically ill myocarditis experience sudden onset, hemodynamic disorders, and fatal arrhythmias. Therefore, early diagnosis and timely treatment of myocarditis are imperative. WHAT IS NEW: • To the best of our knowledge, this multicenter retrospective study is the largest ever reported in China, aiming to reveal the clinical characteristics and outcomes of pediatric clinical myocarditis in China. We provided an extensive analysis of the clinical characteristics, diagnosis, treatment, prognosis, and factors impacting disease severity in pediatric clinical myocarditis in China, which provides insights into the epidemiological characteristics of pediatric clinical myocarditis.

Gasotransmitter-Mediated Cysteinome Oxidative Posttranslational Modifications: Formation, Biological Effects, and Detection.

Significance: Gasotransmitters, including nitric oxide (NO), hydrogen sulfide (H2S) and sulfur dioxide (SO2), participate in various cellular processes via corresponding oxidative posttranslational modifications (oxiPTMs) of specific cysteines. Recent Advances: Accumulating evidence has clarified the mechanisms underlying the formation of oxiPTMs derived from gasotransmitters and their biological functions in multiple signal pathways. Because of the specific existence and functional importance, determining the sites of oxiPTMs in cysteine is crucial in biology. Recent advances in the development of selective probes, together with upgraded mass spectrometry (MS)-based proteomics, have enabled the quantitative analysis of cysteinome. To date, several cysteine residues have been identified as gasotransmitter targets. Critical Issues: To clearly understand the underlying mechanisms for gasotransmitter-mediated biological processes, it is important to identify modified targets. In this review, we summarize the chemical formation and biological effects of gasotransmitter-dependent oxiPTMs and highlight the state-of-the-art detection methods. Future Directions: Future studies in this field should aim to develop the next generation of probes for in situ labeling to improve spatial resolution and determine the dynamic change of oxiPTMs, which can lay the foundation for research on the molecular mechanisms and clinical translation of gasotransmitters. Antioxid. Redox Signal. 40, 145-167.

Serum uric acid predicts therapeutic response to midodrine hydrochloride in children with vasovagal syncope: a pilot study.

Serum uric acid (UA) level has been proven to be related to several cardiovascular and metabolic diseases. In the present study, we examined if baseline serum UA level could predict the therapeutic efficacy of midodrine hydrochloride on vasovagal syncope (VVS) in children. The pediatric VVS patients who received midodrine hydrochloride from November 2008 to October 2022 were enrolled. After a median treatment duration of 3 months, the therapeutic effect was evaluated. According to the patients' responses to midodrine hydrochloride, which was determined by the recurrence of syncope, they were divided into effective and ineffective groups. The baseline variables were explored using univariable and multivariate logistic analysis. The predictive efficacy was assessed by receiver operating characteristic curve (ROC), precision-recall curve (PR), Hosmer-Lemeshow test, calibration curve, and decision curve analysis (DCA). Totally, 53 participants were included in the study. Among the 51 patients who were successfully followed up, 29 (56.9%) responded to midodrine hydrochloride (effective group), and the other 22 (43.1%) failed to respond to midodrine hydrochloride (ineffective group). The participants in effective group had lower baseline serum UA level than those in ineffective group (276.5 ± 73 µmol/L vs. 332.7 ± 56 µmol/L, p = 0.004). Multivariable logistic analysis showed that serum UA was associated with the therapeutic response (odds ratio (OR): 0.985, 95% confidence interval (CI): 0.974-0.997, p = 0.01). ROC analysis indicated that using baseline serum UA < 299 µmol/L as a threshold value yielded a sensitivity of 77.3% and a specificity of 79.3% in predicting the treatment response to midodrine hydrochloride. The area under the PR curve was 0.833. Hosmer-Lemeshow test yielded a p value of 0.58, and calibration plot indicated that the model was well-fitted. DCA demonstrated that treatment decision depending on the baseline serum UA level resulted in a favorable net benefit.   Conclusion: This pilot study suggested that the baseline serum UA level could be taken as a predictor of therapeutic effect of midodrine hydrochloride on VVS in children. What is Known: • Empirical and unselected use of midodrine hydrochloride has an unfavorable therapeutic effect on VVS in children. Serum uric acid (UA) is closely linked to cardiovascular events. What is New: • A low baseline serum UA level successfully predicts the therapeutic effectiveness of midodrine hydrochloride on VVS in children.

Gut Microecology May Be Involved in the Pathogenesis of Hashimoto Thyroiditis by Reducing Production of Hydrogen Sulfide.

CONTEXT: Hashimoto thyroiditis (HT) is related to intestinal microbiota alteration, but the causal relationship remains unclear. Hydrogen sulfide (H2S) is a microbiota-derived metabolite. We speculated that abnormal intestinal microbiota might limit H2S production capacity, promoting HT pathogenesis. OBJECTIVE: This work aimed to illustrate that the intestinal microbiota plays important roles in HT pathogenesis via microbiota-derived H2S levels. METHODS: We collected feces from HT patients and healthy donors for fecal microbiota transplantation (FMT). Thirty-six female CBA/J mice were randomly assigned to 4 groups: experimental autoimmune thyroiditis (EAT) group, EAT + Healthy group, EAT + HT group, and EAT + HT + H2S group. 16S ribosomal RNA sequencing was performed to examine gut microbiota alterations and the H2S production pathway. Serum TgAb and H2S levels were assayed by enzyme-linked immunosorbent assay and H2S-selective sensors, respectively. T-cell subpopulations in the spleen were detected by flow cytometry. RESULTS: The gut microbiota was different after FMT among the EAT, EAT + Healthy, and EAT + HT groups. The thyroiditis score assessed by hematoxylin and eosin staining was higher in the EAT + HT group than that in the EAT and EAT + HT + H2S groups. Helper T (Th1) and Th17 cell differentiation ratios were increased in the EAT + HT group compared to the other 3 groups. Serum H2S levels were decreased and the dissimilatory sulfate reduction (DSR) pathway was attenuated in the EAT + HT group compared to the EAT + Healthy group. CONCLUSION: H2S alleviated thyroiditis severity and related immune disorders, which were aggravated by the FMT from HT patients. The attenuated DSR pathway in the gut microbiota from HT patients might be involved in thyroiditis pathogenesis.

Poincaré plot can help predict the curative effect of metoprolol for pediatric postural orthostatic tachycardia syndrome.

Purpose: To study whether a Poincaré plot can help predict the curative effect of metoprolol for postural orthostatic tachycardia syndrome (POTS) in children. Methods: Pediatric patients with POTS who were administered metoprolol were retrospectively included. The collected data included general data (sex, age, height, weight, and body mass index), the manifestations and treatment (baseline orthostatic intolerance symptom score and course of metoprolol treatment), vital signs (supine heart rate [HR], supine blood pressure, and increased HR during the standing test), HR variability indexes (standard deviation of normal-to-normal intervals [SDNN]; standard deviation of the averages of normal-to-normal intervals [SDANN]; mean standard deviation of the NN intervals for each 5-min segment [SDNNI]; root mean square of the successive differences [rMSSD]; percentage of adjacent NN intervals that differ by >50 ms [pNN50]; triangular index; ultra-low [ULF], very low [VLF], low [LF], and high frequency [HF]; total power [TP]; and LF/HF ratio), and graphical parameters of the Poincaré plot (longitudinal axis [L], transverse axis [T], and L/T). Receiver operator characteristic curves were used to calculate the predictive function of the indexes with significant differences between patients who responded and those who did not. The index combination with the highest predictive value was obtained through series-parallel analysis. Results: Overall, 40 responders and 23 non-responders were included. The L and T in the Poincaré plots and rMSSD, pNN50, HF, and TP of the HR variability data were significantly lower in participants who responded to metoprolol than in participants who did not (p < 0.001). The L/T of participants who responded to metoprolol was greater than that of non-responders (p < 0.001). Moreover, we noted a strong correlation between every two indexes among L, T, rMSSD, pNN50, HF, TP, and L/T (p < 0.05). T < 573.9 ms combined with L/T > 2.9 had the best performance for predicting the effectiveness of metoprolol, with a sensitivity of 85.0%, specificity of 82.6%, and accuracy of 84.1%. Conclusion: In the Poincaré plot, a T < 573.9 ms combined with an L/T > 2.9 helps predict good outcomes of using metoprolol to treat pediatric POTS.

Advances in the research of sulfur dioxide and pulmonary hypertension.

Pulmonary hypertension (PH) is a fatal disease caused by progressive pulmonary vascular remodeling (PVR). Currently, the mechanisms underlying the occurrence and progression of PVR remain unclear, and effective therapeutic approaches to reverse PVR and PH are lacking. Since the beginning of the 21st century, the endogenous sulfur dioxide (SO2)/aspartate transaminase system has emerged as a novel research focus in the fields of PH and PVR. As a gaseous signaling molecule, SO2 metabolism is tightly regulated in the pulmonary vasculature and is associated with the development of PH as it is involved in the regulation of pathological and physiological activities, such as pulmonary vascular cellular inflammation, proliferation and collagen metabolism, to exert a protective effect against PH. In this review, we present an overview of the studies conducted to date that have provided a theoretical basis for the development of SO2-related drug to inhibit or reverse PVR and effectively treat PH-related diseases.

L-cystathionine protects against oxidative stress and DNA damage induced by oxidized low-density lipoprotein in THP-1-derived macrophages.

Introduction: Oxidative stress in monocyte-derived macrophages is a significant pathophysiological process in atherosclerosis. L-cystathionine (L-Cth) acts as a scavenger for oxygen free radicals. However, the impact of L-Cth on macrophage oxidative stress during atherogenesis has remained unclear. This study aimed to investigate whether L-Cth affects oxidative stress in THP-1-derived macrophages and its subsequent effects on DNA damage and cell apoptosis. Methods: We established a cellular model of oxLDL-stimulated macrophages. The content of superoxide anion, H2O2, NO, and H2S in the macrophage were in situ detected by the specific fluorescence probe, respectively. The activities of SOD, GSH-Px, and CAT were measured by colorimetrical assay. The protein expressions of SOD1, SOD2, and iNOS were detected using western blotting. The DNA damage and apoptosis in the macrophage was evaluated using an fluorescence kit. Results: The results demonstrated that oxLDL significantly increased the content of superoxide anion and H2O2, the expression of iNOS protein, and NO production in macrophages. Conversely, oxLDL decreased the activity of antioxidants GSH-Px, SOD, and CAT, and downregulated the protein expressions of SOD1 and SOD2 in macrophages. However, treatment with L-Cth reduced the levels of superoxide anion, H2O2, and NO, as well as the protein expression of iNOS induced by oxLDL. Moreover, L-Cth treatment significantly enhanced GSH-Px, SOD, and CAT activity, and upregulated the expressions of SOD1 and SOD2 proteins in macrophages treated with oxLDL. Furthermore, both L-Cth supplementation and activation of endogenous L-Cth production suppressed DNA damage and cell apoptosis in oxLDL-injured macrophages, whereas inhibition of endogenous L-Cth exacerbated the deleterious effects of oxLDL. Conclusion: These findings suggest that L-Cth exerts a pronounced inhibitory effect on the oxidative stress, subsequent DNA damage and cell apoptosis in oxLDL-stimulated THP-1 monocytes. This study deepens our understanding of the pathogenesis of macrophage-related cardiovascular pathology.

Predicting Therapeutic Efficacy of Pharmacological Treatments in Children with Postural Orthostatic Tachycardia Syndrome: A Mini-Review.

Postural orthostatic tachycardia syndrome (POTS) is common in children, with an excessive increment in heart rate when moving from the supine to upright position. It has significant negative impacts on the daily life of pediatric patients. The pathogenesis of POTS includes peripheral vascular dysfunction, central hypovolemia, abnormal autonomic function, a high-adrenergic state, impaired skeletal-muscle pump function, the abnormal release of vasoactive factors, and autoimmune abnormalities. Therefore, the empirical use of pharmacological treatments has limited therapeutic efficacy due to the diversity of its mechanisms. A crucial aspect of managing POTS is the selection of appropriate treatment targeting the specific pathogenesis. This review summarizes the commonly used pharmacological interventions, with a focus on their predictive indicators for treatment response. Factors such as heart rate variability, plasma biomarkers, and cardiac-function parameters are discussed as potential predictors of therapeutic efficacy, enabling the implementation of individualized treatment to improve therapeutic effectiveness. This review consolidates the current knowledge on POTS, encompassing its clinical characteristics, epidemiological patterns, underlying pathogenic mechanisms, and predictive indicators for treatment response. Further research is warranted to enhance the understanding of POTS and facilitate the development of more effective therapeutic approaches for this challenging syndrome.

Hypoxia inducible factor-1α is an important regulator of macrophage biology.

Hypoxia-inducible factor-1 (HIF-1), a heterodimeric transcription factor composed of the α and ß subunits, regulates cellular adaptive responses to hypoxia. Macrophages, which are derived from monocytes, function as antigen-presenting cells that activate various immune responses. HIF-1α regulates the immune response, viability, migration, phenotypic plasticity, and metabolism of macrophages. Specifically, macrophage-derived HIF-1α can prevent excessive pro-inflammatory responses by attenuating the transcriptional activity of nuclear factor-kappa B in vivo and in vitro. HIF-1α modulates macrophage migration by inducing the release of various chemokines and providing necessary energy. HIF-1α promotes macrophage M1 polarization by targeting glucose metabolism. Additionally, HIF-1α induces the upregulation of glycolysis-related enzymes and intermediates of the tricarboxylic acid cycle and pentose phosphate pathway. HIF-1α promotes macrophage apoptosis, necroptosis and reduces autophagy. The current review highlights the mechanisms associated with the regulation of HIF-1α stabilization in macrophages as well as the role of HIF-1α in modulating the physiological functions of macrophages.

Alteration of Intestinal Microbiota and Hydrogen Sulfide Metabolism in Patients with Hashimoto's Thyroiditis.

Objective: To analyze the intestinal microbiota and H2S levels in patients with HT. Methods: Twenty euthyroid HT patients and twenty healthy control individuals were recruited. Fecal samples were collected, and the microbiota was examined using 16S RNA gene sequencing. We also collected serum samples to examine the H2S levels. Results: Compared with patients with HT, the ACE and Chao indices were significantly lower in healthy controls (P=0.04, 0.03, respectively). The microbial composition of the HT group differed significantly from that of the healthy group. We observed a significant increase in the proportions of Bacteroides, Fusobacterium, Sutterella, and Veillonella in patients with HT (P < 0.05). Linear discriminant analysis and effect size analysis also revealed that Bacteroides and Ralstonia were enriched in patients with HT. Additionally, patients with HT had significantly lower H2S levels than healthy controls (P < 0.005). The enrichment of H2S anabolism was linked to the alteration of intestinal microbiota in patients with HT. Conclusion: We demonstrated that patients with HT have aberrant intestinal microbiome and that H2S anabolism may contribute to HT pathogenesis.

Predicting therapeutic efficacy of oral rehydration salts in children with vasovagal syncope.

Objective: This study was designed to develop an easy-to-perform and inexpensive measure to predict efficacy of the oral rehydration salts (ORS) in children with vasovagal syncope (VVS). Materials and methods: Children diagnosed with VVS and treated with ORS for a median of 3 months at the Peking University First Hospital, China, were enrolled and followed up. Demographic data, clinical hemodynamic parameters, and variables related to red blood cells were collected at the baseline. On the basis of changes in symptom scores after treatment, participants were divided into effective or ineffective groups at the end of the follow-up. Logistic regression analysis was used to investigate parameters related to therapeutic efficacy of ORS and a predictive model of ORS effectiveness was created. The predictive efficiency was evaluated using the receiver operating characteristic curve. The accuracy/consistency was evaluated by the Hosmer-Lemeshow test and calibration curve. Internal validation was done using the bootstrap approach. Results: Totally 97 pediatric participants were included in the study and 4 (4.1%) were lost during the follow-up. ORS therapy was effective in 46 children and ineffective in 47 children. Children in the effective group had higher baseline red blood cell count, hemoglobin, and hematocrit than those in the ineffective group (p < 0.01). Through logistic regression analysis, the baseline hematocrit and body mass index (BMI) were included in predictive model for the response to ORS treatment. The predictive efficacy of the model showed an area under the curve of 0.77 (p < 0.01). The predicted probability cut-off value of 0.5 was found to be optimal, with a resulting sensitivity of 67.4% and specificity of 80.9%. In the Hosmer-Lemeshow test, p-value was 0.75, and the calibration plot showed a good model fitness. Internal validation was performed using the bootstrap approach (n = 1,000), showing 95% confidence interval of 0.67-0.86. Conclusion: Hemoglobin combined with BMI was useful for predicting the therapeutic efficacy of ORS in children with VVS.

Markers for predicting the efficacy of beta-blockers in vasovagal syncope management in children: A mini-review.

Vasovagal syncope (VVS) is a common subtype of neurally mediated syncope. It is prevalent in children and adolescents, and critically affects the quality of life of patients. In recent years, the management of pediatric patients with VVS has received extensive attention, and ß-blocker serves as an important choice of the drug therapy for children with VVS. However, the empirical use of ß-blocker treatment has limited therapeutic efficacy in patients with VVS. Therefore, predicting the efficacy of ß-blocker therapy based on biomarkers related to the pathophysiological mechanism is essential, and great progress has been made by applying these biomarkers in formulating individualized treatment plans for children with VVS. This review summarizes recent advances in predicting the effect of ß-blockers in the management of VVS in children.

A predictive model of response to metoprolol in children and adolescents with postural tachycardia syndrome.

BACKGROUND: The present work was designed to explore whether electrocardiogram (ECG) index-based models could predict the effectiveness of metoprolol therapy in pediatric patients with postural tachycardia syndrome (POTS). METHODS: This study consisted of a training set and an external validation set. Children and adolescents with POTS who were given metoprolol treatment were enrolled, and after follow-up, they were grouped into non-responders and responders depending on the efficacy of metoprolol. The difference in pre-treatment baseline ECG indicators was analyzed between the two groups in the training set. Binary logistic regression analysis was further conducted on the association between significantly different baseline variables and therapeutic efficacy. Nomogram models were established to predict therapeutic response to metoprolol. The receiver-operating characteristic curve (ROC), calibration, and internal validation were used to evaluate the prediction model. The predictive ability of the model was validated in the external validation set. RESULTS: Of the 95 enrolled patients, 65 responded to metoprolol treatment, and 30 failed to respond. In the responders, the maximum value of the P wave after correction (Pcmax), P wave dispersion (Pd), Pd after correction (Pcd), QT interval dispersion (QTd), QTd after correction (QTcd), maximum T-peak-to-T-end interval (Tpemax), and T-peak-to-T-end interval dispersion (Tped) were prolonged (all P < 0.01), and the P wave amplitude was increased (P < 0.05) compared with those of the non-responders. In contrast, the minimum value of the P wave duration after correction (Pcmin), the minimum value of the QT interval after correction (QTcmin), and the minimum T-peak-to-T-end interval (Tpemin) in the responders were shorter (P < 0.01, < 0.01 and < 0.01, respectively) than those in the non-responders. The above indicators were screened based on the clinical significance and multicollinearity analysis to construct a binary logistic regression. As a result, pre-treatment Pcmax, QTcmin, and Tped were identified as significantly associated factors that could be combined to provide an accurate prediction of the therapeutic response to metoprolol among the study subjects, yielding good discrimination [area under curve (AUC) = 0.970, 95% confidence interval (CI) 0.942-0.998] with a predictive sensitivity of 93.8%, specificity of 90.0%, good calibration, and corrected C-index of 0.961. In addition, the calibration curve and standard curve had a good fit. The accuracy of internal validation with bootstrap repeated sampling was 0.902. In contrast, the kappa value was 0.769, indicating satisfactory agreement between the predictive model and the results from the actual observations. In the external validation set, the AUC for the prediction model was 0.895, and the sensitivity and specificity were 90.9% and 95.0%, respectively. CONCLUSIONS: A high-precision predictive model was successfully developed and externally validated. It had an excellent predictive value of the therapeutic effect of metoprolol on POTS among children and adolescents.

Hydrogen Sulfide Regulates Macrophage Function in Cardiovascular Diseases.

Significance: Hydrogen sulfide (H2S) is an endogenous gasotransmitter that plays a vital role in immune system regulation. Recently, the regulation of macrophage function by H2S has been extensively and actively recognized. Recent Advances: The mechanisms by which endogenous H2S controls macrophage function have attracted increasing attention. The generation of endogenous H2S from macrophages is mainly catalyzed by cystathionine-γ-lyase. H2S is involved in the macrophage activation and inflammasome formation, which contributes to macrophage apoptosis, adhesion, chemotaxis, and polarization. In addition, H2S has redox ability and interacts with reactive oxygen species to prevent oxidative stress. Moreover, H2S epigenetically regulates gene expression. Critical Issues: In this article, the generation of endogenous H2S in macrophages and its regulatory effect on macrophage function are reviewed. In addition, the signal transduction targeting macrophages by H2S is also addressed. Finally, the potential therapeutic effect of H2S on macrophages is discussed. Future Directions: Further experiments are required to explore the involvement of endogenous H2S in the regulation of macrophage function in various physiological and pathophysiological processes and elucidate the mechanisms involved. Regarding the clinical translation of H2S, further exploration of the application of H2S in inflammation-related diseases is needed. Antioxid. Redox Signal. 38, 45-56.