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.

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.

Baseline left ventricular ejection fraction associated with symptom improvements in both children and adolescents with postural tachycardia syndrome under metoprolol therapy.

BACKGROUND: Postural tachycardia syndrome (POTS) is a common childhood disease that seriously affects the patient's physical and mental health. This study aimed to investigate whether pre-treatment baseline left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) values were associated with symptom improvement after metoprolol therapy for children and adolescents with POTS. METHODS: This retrospective study evaluated 51 children and adolescents with POTS who received metoprolol therapy at the Peking University First Hospital between November 2010 and July 2019. All patients had completed a standing test or basic head-up tilt test and cardiac echocardiography before treatment. Treatment response was evaluated 3 months after starting metoprolol therapy. The pre-treatment baseline LVEF and LVFS values were evaluated for correlations with decreases in the symptom score after treatment (ΔSS). Multivariable analysis was performed using factors with a P value of <0.100 in the univariate analyses and the demographic characteristics. RESULTS: A comparison of responders and non-responders revealed no significant differences in demographic, hemodynamic characteristics, and urine specific gravity (all P > 0.050). However, responders had significantly higher baseline LVEF (71.09% ±â€Š4.44% vs. 67.17% ±â€Š4.88%, t = -2.789, P = 0.008) and LVFS values (40.00 [38.00, 42.00]% vs. 36.79% ±â€Š4.11%, Z = -2.542, P = 0.010) than the non-responders. The baseline LVEF and LVFS were positively correlated with ΔSS (r = 0.378, P = 0.006; r = 0.363, P = 0.009), respectively. Logistic regression analysis revealed that LVEF was independently associated with the response to metoprolol therapy in children and adolescents with POTS (odds ratio: 1.201, 95% confidence interval: 1.039-1.387, P = 0.013). CONCLUSIONS: Pre-treatment baseline LVEF was associated with symptom improvement after metoprolol treatment for children and adolescents with POTS.

Interaction among Hydrogen Sulfide and Other Gasotransmitters in Mammalian Physiology and Pathophysiology.

Hydrogen sulfide (H2S), nitric oxide (NO), carbon monoxide (CO), and sulfur dioxide (SO2) were previously considered as toxic gases, but now they are found to be members of mammalian gasotransmitters family. Both H2S and SO2 are endogenously produced in sulfur-containing amino acid metabolic pathway in vivo. The enzymes catalyzing the formation of H2S are mainly CBS, CSE, and 3-MST, and the key enzymes for SO2 production are AAT1 and AAT2. Endogenous NO is produced from L-arginine under catalysis of three isoforms of NOS (eNOS, iNOS, and nNOS). HO-mediated heme catabolism is the main source of endogenous CO. These four gasotransmitters play important physiological and pathophysiological roles in mammalian cardiovascular, nervous, gastrointestinal, respiratory, and immune systems. The similarity among these four gasotransmitters can be seen from the same and/or shared signals. With many studies on the biological effects of gasotransmitters on multiple systems, the interaction among H2S and other gasotransmitters has been gradually explored. H2S not only interacts with NO to form nitroxyl (HNO), but also regulates the HO/CO and AAT/SO2 pathways. Here, we review the biosynthesis and metabolism of the gasotransmitters in mammals, as well as the known complicated interactions among H2S and other gasotransmitters (NO, CO, and SO2) and their effects on various aspects of cardiovascular physiology and pathophysiology, such as vascular tension, angiogenesis, heart contractility, and cardiac protection.

Prediction of intravenous immunoglobulin resistance in Kawasaki disease in children.

BACKGROUND: We aimed to explore predictive measures for intravenous immunoglobulin (IVIG) resistance in children with Kawasaki disease (KD). METHODS: Patients diagnosed with KD were enrolled in this study. Univariate analysis and multiple logistic regression were utilized to analyze the clinical features and laboratory results prior to IVIG-treatment of the two groups. Independent predictors of IVIG resistance were analyzed, and a predictive model for KD children with IVIG resistance was constructed. RESULTS: A total of 277 children with KD, 180 boys and 97 girls, aged 2-128 (median 23) months, were enrolled in the study. Compared with the IVIG-responsive group, the IVIG-resistant group had higher levels of the peripheral neutrophil count, mean platelet volume, mean platelet volume-to-lymphocyte ratio and C-reactive protein, and total serum bilirubin, but lower levels of peripheral lymphocyte count, serum albumin and serum prealbumin. Age (in months), peripheral neutrophil count, lymphocyte count and mean platelet volume and serum albumin were independent indicators for IVIG resistance by multivariate logistic regression analysis. A logistic regression model and a scoring system were set up, where cut-off values of - 0.46 and 6.5 points yielded sensitivities of 83.9% and 77.4%, and specificities of 74.8% and 61.0%, respectively. The areas under the curve (AUC) were 0.808 in the logistic regression model, and 0.750 in the scoring system. CONCLUSION: Our model for predicting IVIG-resistant children with KD, involving age (months), peripheral neutrophil count, lymphocyte count and mean platelet volume and serum albumin prior to IVIG-treatment, is helpful for clinical prediction of children with IVIG-resistant KD.

Body mass index is a promising predictor of response to oral rehydration saline in children with vasovagal syncope.

BACKGROUND: Vasovagal syncope (VVS) greatly impairs quality of life. The therapeutic efficacy of oral rehydration saline (ORS) for unselected VVS patients is not satisfactory due to the diverse mechanisms of the disease. Body mass index (BMI) was demonstrated to reflect blood volume to a certain extent. Therefore, the present study explored the capability of BMI to predict the therapeutic response of children with VVS to ORS treatment. METHODS: Seventy-four children with VVS who visited the Syncope Unit of Pediatrics at Peking University First Hospital from November 2010 to June 2019 receiving ORS treatment were enrolled for this retrospective case-control study. A comparison of demographic, clinical, and hemodynamic characteristics was performed between responders and non-responders. The correlation between baseline BMI and response time was analyzed. To determine the value of baseline BMI in predicting the therapeutic efficacy of ORS in children with VVS, a receiver operating characteristic curve analysis was performed. RESULTS: Fifty-two children were identified as responders, and the remaining 22 children were identified as non-responders. The baseline BMI of the responders was much lower than that of the non-responders (16.4 [15.5, 17.8] kg/m2vs. 20.7 ±e6 kg/m2, P < 0.001), and baseline BMI was positively correlated with response time in the head-up tilt test after adjusting for sex (r = 0.256, 95% confidence interval [CI]: 0.067-0.439, P = 0.029). The area under the receiver operating characteristic curve of baseline BMI was 0.818 (95% CI: 0.704-0.932, P < 0.001), and an optimal cut-off value of 18.9 kg/m2 yielded a sensitivity of 83% and a specificity of 73% to predict the efficacy of ORS in VVS. CONCLUSION: Prior to treatment, baseline BMI is a promising predictor of response to ORS in children with VVS.

Gut microbiota analysis and its significance in vasovagal syncope in children.

BACKGROUND: Vasovagal syncope (VVS) is common in children and greatly affect both physical and mental health. But the mechanisms have not been completely explained. This study was designed to analyze the gut microbiota in children with VVS and explore its clinical significance. METHODS: Fecal samples from 20 VVS children and 20 matched controls were collected, and the microbiota were analyzed by 16S rRNA gene sequencing. The diversity and microbiota compositions of the VVS cases and controls were compared with the independent sample t test or Mann-Whitney U test. The correlation between the predominant bacteria and clinical symptoms was analyzed using Pearson or Spearman correlation test. RESULTS: No significant differences in diversity were evident between VVS and controls (P > 0.05). At the family level, the relative abundance of Ruminococcaceae was significantly higher in VVS children than in controls (median [Q1, Q3]: 22.10% [16.89%, 27.36%] vs. 13.92% [10.31%, 20.18%], Z = -2.40, P < 0.05), and LEfSe analysis revealed Ruminococcaceae as a discriminative feature (linear discriminant analysis [LDA] score > 4, P < 0.05). The relative abundance of Ruminococcaceae in VVS patients was positively correlated with the frequency of syncope (r = 0.616, P < 0.01). In terms of its correlation with hemodynamics, we showed that relative abundance of Ruminococcaceae was negatively correlated with the systolic and diastolic pressure reduction at the positive response in head-up tilt test (HUTT; r = -0.489 and -0.448, all P < 0.05), but was positively correlated with the mean pressure drop and decline rate (r = 0.489 and 0.467, all P < 0.05) as well as diastolic pressure drop and decline rate at the HUTT positive response (r = 0.579 and 0.589, all P < 0.01) in VVS patients. CONCLUSION: Ruminococcaceae was the predominant gut bacteria and was associated with the clinical symptoms and hemodynamics of VVS, suggesting that gut microbiota might be involved in the development of VVS.

Role of endoplasmic reticulum stress-associated gene TRIB3 in rats following kainic acid-induced seizures.

TRIB3 (tribblespseudokinase 3) is a pseudokinase that affects several cellular functions, and its expression is increased during endoplasmic reticulum stress (ER stress). How recurrent seizures affect the regulation of TRIB3 in the hippocampus during epilepsy remains unclear. In this study, we investigated the role of TRIB3 in the kainic acid (KA)-induced seizures and related brain injury. In a rat model of kainic acid-induced seizures, neuronal excitotoxic injury and apoptosis, and increases in the expression of TRIB3 and ER stress markers glucose-regulated protein 78 (GRP78) and C/EBP homologous binding protein (CHOP) were observed in the hippocampus by 24 h to 30 d after KA administration. Furthermore, phosphorylation of AKT, which is inhibited by TRIB3, was decreased in the hippocampus after KA-evoked seizure. These results indicate that ER stress, TRIB3 and AKT signaling are involved in the acute and prolonged hippocampal injury following KA induced seizure, suggesting that the ER stress-associated gene TRIB3 plays an important role in neuronal apoptosis after seizure.

Inhibitory Effects of Sulfur Dioxide on Rat Myocardial Fibroblast Proliferation and Migration.

BACKGROUND: Myocardial fibrosis is an important pathological change in many heart diseases, but its pathogenesis is very complex and has not yet been fully elucidated. The study was designed to examine whether endogenous sulfur dioxide (SO2) is a novel myocardial fibroblast proliferation and migration inhibitor. METHODS: Primary rat myocardial fibroblasts were isolated and transfected with aspartate aminotransferase (AAT1 and AAT2) knockdown lentivirus or empty lentivirus. SO2 content in the supernatant was determined with high-performance liquid chromatography, and the expressions of AAT1, AAT2, proliferating cell nuclear antigen (PCNA), phosphorylated extracellular signal-regulated protein kinase (p-ERK), and total ERK (T-ERK) in the cells were detected. Cell migration was detected by wound healing test. Independent sample t-test (for two groups) and one-way analysis of variance (three or more groups) were used to analyze the results. RESULTS: Both AAT1 and AAT2 knockdown significantly reduced SO2levels (F = 31.46, P < 0.01) and AAT1/2 protein expression (AAT1, t = 12.67, P < 0.01; AAT2, t = 9.61, P < 0.01), but increased PCNA expression and Cell Counting Kit-8 (CCK-8) activity as well as the migration in rat primary myocardial fibroblasts (P < 0.01). Supplementation of SO2rather than pyruvate significantly inhibited the increase in proliferation and migration caused by AAT knockdown (P < 0.01). Mechanistically, the ratio of p-ERK to T-ERK was significantly increased in the AAT1/2 knockdown groups compared with that in the empty lentivirus group (AAT1, t = -7.36, P < 0.01; AAT2, t = -10.97, P < 0.01). Whereas PD98059, an inhibitor of ERK activation, successfully blocked AAT knockdown-induced PCNA upregulation (F = 74.01, P > 0.05), CCK-8 activation (F = 50.14, P > 0.05), and migration augmentation in myocardial fibroblasts (24 h, F = 37.08, P > 0.05; 48 h, F = 58.60, P > 0.05). CONCLUSION: Endogenous SO2might be a novel myocardial fibroblast proliferation and migration inhibitor via inhibiting the ERK signaling pathway.

Hydrogen Sulfide Regulating Myocardial Structure and Function by Targeting Cardiomyocyte Autophagy.

OBJECTIVE: Hydrogen sulfide (H2S), a gaseous signal molecule, plays a crucial role in many pathophysiologic processes in the cardiovascular system. Autophagy has been shown to participate in the occurrence of many cardiac diseases. Increasing evidences indicated that H2S regulates myocardial structure and function in association with the altered autophagy and plays a "switcher" role in the autophagy of myocardial diseases. The aim of this review was to summarize these insights and provide the experimental evidence that H2S targets cardiomyocyte autophagy to regulate cardiovascular function. DATA SOURCES: This review was based on data in articles published in the PubMed databases up to October 30, 2017, with the following keywords: "hydrogen sulfide," "autophagy," and "cardiovascular diseases." STUDY SELECTION: Original articles and critical reviews on H2S and autophagy were selected for this review. RESULTS: When autophagy plays an adaptive role in the pathogenesis of diseases, H2S restores autophagy; otherwise, when autophagy plays a detrimental role, H2S downregulates autophagy to exert a cardioprotective function. For example, H2S has beneficial effects by regulating autophagy in myocardial ischemia/reperfusion and plays a protective role by inhibiting autophagy during the operation of cardioplegia and cardiopulmonary bypass. H2S postpones cardiac aging associated with the upregulation of autophagy but improves the left ventricular function of smoking rats by lowering autophagy. CONCLUSIONS: H2S exerts cardiovascular protection by regulating autophagy. Cardiovascular autophagy would likely become a potential target of H2S therapy for cardiovascular diseases.

Increased Endogenous Sulfur Dioxide Involved in the Pathogenesis of Postural Tachycardia Syndrome in Children: A Case-Control Study.

BACKGROUND: The pathogenesis of postural tachycardia syndrome (POTS) remains unclear. This study aimed to explore the changes and significance of sulfur dioxide (SO2) in patients with POTS. METHODS: The study included 31 children with POTS and 27 healthy children from Peking University First Hospital between December 2013 and October 2015. A detailed medical history, physical examination results, and demographic characteristics were collected. Hemodynamics was recorded and the plasma SO2was determined. RESULTS: The plasma SO2was significantly higher in POTS children compared to healthy children (64.0 ± 20.8 µmol/L vs. 27.2 ± 9.6 µmol/L, respectively, P < 0.05). The symptom scores in POTS were positively correlated with plasma SO2levels (r = 0.398, P < 0.05). In all the study participants, the maximum heart rate (HR) was positively correlated with plasma levels of SO2(r = 0.679, P < 0.01). The change in systolic blood pressure from the supine to upright (ΔSBP) in POTS group was smaller than that in the control group (P < 0.05). The ΔSBP was negatively correlated with baseline plasma SO2levels in all participants (r = -0.28, P < 0.05). In the control group, ΔSBP was positively correlated with the plasma levels of SO2(r = 0.487, P < 0.01). The change in HR from the supine to upright in POTS was obvious compared to that of the control group. The area under curve was 0.967 (95% confidence interval: 0.928-1.000), and the cutoff value of plasma SO2 level >38.17 µmol/L yielded a sensitivity of 90.3% and a specificity of 92.6% for predicting the diagnosis of POTS. CONCLUSIONS: Increased endogenous SO2levels might be involved in the pathogenesis of POTS.

Vascular dysfunction of postural tachycardia syndrome in children.

BACKGROUND: Postural orthostatic tachycardia syndrome (POTS) is a form of orthostatic intolerance, and its incidence in children is approximately 6.8% [1]. The pathogenesis of POTS is complex with multiple, overlapping, interacting pathophysiological mechanisms. Although the specific pathogenic mechanism has remained perplexing, with the discovery of various gasotransmitters and biological peptides, the vascular dysfunction has aroused overwhelming attention. DATA SOURCES: On the basis of searching in a wide range of recent original literatures, we reviewed the pathogenesis of vascular dysfunction in children with POTS. RESULTS: The flow-mediated vasodilation of POTS patients was greater than that of healthy controls, and the vasodilator factors were increased in patients with POTS under basal condition or under a standing position, while the vasoconstriction factors were reduced. CONCLUSIONS: Vascular dysfunction, as one of pathogenesis in pediatric POTS patients, affects the occurrence and development of diseases through a variety of factors.