Shao-Ju Chien

Melatonin prevents neonatal dexamethasone induced programmed hypertension: Histone deacetylase inhibition

Adulthood hypertension can be programmed by corticosteroid exposure in early life. Oxidative stress, epigenetic regulation by histone deacetylases (HDACs), and alterations of renin-angiotensin system (RAS) are involved in the developmental programming of hypertension. We examined whether melatonin prevented neonatal dexamethasone (DEX)-induced programmed hypertension and how melatonin prevented these processes. We also examined whether HDAC inhibition by trichostatin A (TSA, a HDAC inhibitor) had similar effects. Male offspring were assigned to 5 groups (n=6/group): control, DEX, melatonin, DEX+melatonin, and DEX+TSA. Male rat pups were injected i.p. with DEX on day 1 (0.5mg/kg BW), day 2 (0.3mg/kg BW), and day 3 (0.1mg/kg BW) after birth. Melatonin was administered in drinking water at the dose of 0.01% during the lactation period. The DEX+TSA group received DEX and 0.5mg/kg TSA subcutaneous injection once daily for 1 week. All rats were killed at 16 weeks of age. Neonatal DEX exposure induced hypertension in male offspring at 16 weeks of age, which melatonin prevented. Neonatal DEX exposure decreased gene expression related to apoptosis, nephrogenesis, RAS, and sodium transporters. Yet DEX treatment increased protein levels of HDAC-1, -2, and -3 in the kidney. Melatonin therapy preserved the decreases of gene expression and decreased HDACs. Similarly, HDAC inhibition prevented DEX-induced programmed hypertension. In conclusion, melatonin therapy exerts a long-term protection against neonatal DEX-induced programmed hypertension. Its beneficial effects include alterations of RAS components and inhibition of class I HDACs. Given that the similar protective effects of melatonin and TSA, melatonin might inhibit HDACs to epigenetic regulation of hypertension-related genes to prevent programmed hypertension.

Myocarditis Complicated by Complete Atrioventricular Block: Nine Years' Experience in a Medical Center

BACKGROUND Myocarditis complicated with complete atrioventricular block (CAVB) is rare in children. The purpose of this study was to report the outcome of myocarditis with CAVB in our institution. METHODS Between June 1998 and June 2007, nine pediatric patients (aged from 1.5 to 16 years) were admitted, presenting with acute myocarditis with CAVB. We analyzed their clinical presentations, biochemistry and serology studies, chest X-rays, electrocardiograms, echocardiography, complications and outcomes. RESULTS Hypotension and Stokes-Adams seizures occurred in five and four of our patients, respectively. Cardiomegaly of chest X-ray was common in eight (89%) of our patients. Echocardiography revealed impaired left ventricular performance in three patients. Six patients suffered ventricular tachycardia (VT). Three cases of VT occurred before pacemaker implantation and the others occurred afterwards. Eight patients survived. Six of them regained sinus rhythm within 12 days (range 1-12 days), and two had a right bundle branch block at follow-up. Two patients had persistent CAVB, and one received permanent pacemaker implantation; the other received supportive care. One patient died due to persistent low cardiac output and a new onset of VT on the 4th admission day. During a follow-up period of 56+/-27 months, all eight surviving patients remained asymptomatic. CONCLUSIONS The outcome of CAVB complicated with myocarditis is variable. Most of our patients resumed normal heart function. The incidence of persistent CAVB was 22%. VT is a common and serious complication, but it can be effectively treated medically. Persistent low cardiac output after pacemaker implantation and late onset VT should be considered as risk factors of mortality.

Urinary arginine methylation index associated with ambulatory blood pressure abnormalities in children with chronic kidney disease.

Arginine (ARG) metabolites are interrelated and are involved in chronic kidney disease (CKD) and cardiovascular disease. Twenty-four-hour ambulatory blood pressure monitoring (ABPM) appears to correlate with cardiovascular outcomes. We investigated the relationship between ARG metabolites, and their combined ratios in urine, and the ABPM profiles of children and adolescents with CKD. This cross-sectional study included 45 children and adolescents (age, 5-18 years) with stage 1 to 4 CKD. Each child underwent office blood pressure (BP) measurements, 24-hour ABPM, and urinary ARG metabolite determinations. Seventy percent of children with CKD had abnormal 24-hour ABPM profiles, including nocturnal hypertension, increased BP load, and nondipping nocturnal BP. The urinary ARG-to-asymmetric dimethylarginine (ADMA) ratio was lower, and the ADMA-to-symmetric dimethylarginine (SDMA) ratio was higher in children with advanced CKD (stages 2-4) than those with stage 1 CKD. CKD patients with BP abnormalities also had reduced urinary ARG and dimethylamine (DMA) levels. The higher urinary (ADMA+SDMA)-to-ARG ratios were correlated to ABPM abnormalities, including increased systolic BP load and non-dipping nocturnal BP. ABPM abnormalities were significantly associated with a high urinary (ADMA+SDMA)-to-ARG ratio, suggesting the possible involvement of methylated ARG in the development of hypertension among children with CKD.

Aminoguanidine attenuates hypertension, whereas 7-nitroindazole exacerbates kidney damage in spontaneously hypertensive rats: the role of nitric oxide.

Nitric oxide (NO) deficiency contributes to hypertension and end-organ damage. Three nitric oxide synthase (NOS) isoforms have been identified: neuronal NOS (nNOS), inducible NOS (iNOS), and endothelial NOS (eNOS). Whether selective nNOS or iNOS inhibition exacerbates kidney damage in spontaneously hypertensive rats (SHRs) remains unclear. Seven-week-old SHRs were randomly assigned to 4 groups (n=8 for each group): group 1, SHRs receiving no treatment; group 2 (SHR+7-NI), SHRs given 7-nitroindazole (7-NI, nNOS inhibitor) in their drinking water (10mg/kg/day); group 3 (SHR+salt), SHRs given 1% NaCl; and group 4 (SHR+AG), SHRs given 0.1% aminoguanidine (AG; iNOS inhibitor) in drinking water. The mean arterial pressure of SHRs treated with salt was significantly elevated compared with untreated controls. While AG caused a decrease of mean arterial pressure at 8 and 12 weeks of age in SHRs, both 7-NI and salt exacerbated kidney injury. In addition, AG significantly increased l-arginine levels and the l-arginine-to-asymmetric dimethylarginine (ADMA) ratio in the kidney. Salt treatment decreased renal nNOS-α protein levels and reduced dimethylarginine dimethylaminohydrolase (DDAH) activity. Salt and AG treatment increased nNOS-β and l-citrulline levels in SHR kidneys. AG attenuates hypertension development by upregulation of l-citrulline-to- l-arginine conversion and an increase in the l-arginine-to-ADMA ratio in SHR kidneys. 7-NI impairs renal function but has no effect on blood pressure, suggesting reno-protective role for the nNOS. Salt exacerbates kidney damage mainly through decreasing renal nNOS-α protein levels and DDAH activity. Our findings highlight the protective role of the nNOS/NO pathway in the development of kidney damage in SHRs.

Homocysteine and Arginine-to-Asymmetric Dimethylarginine Ratio Associated With Blood Pressure Abnormalities in Children With Early Chronic Kidney Disease

BACKGROUND Less attention has been paid to evaluating subclinical cardiovascular disease (CVD) in the early stage of pediatric chronic kidney disease (CKD). Ambulatory blood pressure monitoring (ABPM) and arterial stiffness are the earliest detectable assessments of subclinical CVD. Asymmetric dimethylarginine (ADMA) is an analog of L-arginine (ARG) that inhibits nitric oxide (NO) production; thus the ARG-to-ADMA ratio (AAR) is an index of NO. Homocysteine (HCY) is a risk factor for CVD and it can be metabolized to L-cysteine (CYS). Given that HCY and ADMA/NO are closely linked and related to hypertension, we therefore investigated whether ARG and HCY metabolites, arterial stiffness parameters, ABPM profile, and left ventricular hypertrophy (LVH) are interrelated in children and adolescents with early CKD. METHODSANDRESULTS This cross-sectional study included 57 pediatric patients with CKD stages 1-3. Two-thirds of the children with CKD stages 1-3 exhibited BP abnormalities accessed by ABPM. Children with CKD stages 2-3 had higher HCY, but lower CYS levels. The plasma HCY level was increased in children with LVH and abnormal ABPM. Systolic BP positively correlated with biomarkers AAR, HCY, and CYS. LV mass positively correlated with AAR, HCY, and CYS. CONCLUSIONS BP abnormalities were prevalent and associated with AAR, HCY, and CYS in children with early CKD. Our data highlighted the effect of NO and the HCY pathway on CKD-related hypertension.

Transcatheter Closure of Atrial Septal Defects with Superior-anterior Rim Deficiency Using Amplatzer Septal Occluder

BACKGROUND/PURPOSE To evaluate the outcome of transcatheter closure of atrial septal defects (ASD) with superior-anterior (SA) rim deficiency using Amplatzer septal occluder (ASO). METHODS Between June 2003 and March 2007, 84 patients with secundum type ASD attempted transcatheter insertion of ASO in our institution. According to the transesophageal echocardiographic findings, patients were divided into two groups: group A, with deficient SA rim (< 3 mm); group B, with sufficient SA rim (> or = 3 mm). There were 43 children and 41 adults (age range, 2.0-79.4 years; mean age, 22.0 +/- 20.2 years). The failure rate, complications and the presence of residual shunt were compared between the two groups. RESULTS There were 34 patients in group A and 50 patients in group B. Failure of ASO implantation occurred in six patients, three in each group. One patient had two ASOs implanted for two separate ASDs. Therefore, the study cohort consisted of 78 patients with 79 ASO placed. Among 78 patients with successful implantation, five (6.4%) had persistent small residual shunt during follow-up (range, 1-46 months; mean, 21.6 +/- 12.0 months). There was no statistically significant difference between group A and group B in the procedures failure rate (p = 0.682), complications (p = 1.0) and the presence of residual shunt (p = 0.381) during the follow-up period. CONCLUSION ASD with deficient SA rim is a common variation. Similar to ASD with sufficient rims, transcatheter closure of secundum type ASD is also effective for ASD with SA rim deficiency.

Drug reaction with eosinophilia and systemic symptoms syndrome associated myocarditis: a survival experience after extracorporeal membrane oxygenation support

Myocarditis that develops because of the drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a life‐threatening disease. We report a case of DRESS‐associated myocarditis with cardiac failure that required extracorporeal membrane oxygenation (ECMO) for cardiovascular support.

Balloon Angioplasty for Native Coarctation of the Aorta in Neonates and Infants With Congestive Heart Failure

BACKGROUND Balloon angioplasty (BA) is an alternative to surgical repair for coarctation of the aorta (CoA) in children. However, its role in the treatment of native CoA in neonates and infants remains controversial. The purpose of this study was to report the midterm outcomes of BA for native CoA in neonates and infants with congestive heart failure (CHF). METHODS Between July 2000 and March 2007, 18 neonates and infants with native CoA and CHF who underwent BA were enrolled. Patients without recoarctation were designated as group A, while those with recoarctation or CHF were designated as group B. The clinical presentations, laboratory data, and outcomes were compared between groups. RESULTS There were 10 patients in group A and eight in group B. The mean age was 2.8 +/- 3.1 months (range, 0.7-11 months). Mean body weight was 4.0 +/- 1.9 kg (range, 2.1-8.0kg). CHF improved markedly in all patients immediately after BA, with a reduction in systolic pressure gradient from 36.4 +/- 12.0 to 5.6 +/- 6.0 mmHg (p < 0.001). The recoarctation rate was 44% (8/18). The risk factors for restenosis were post-BA systolic pressure gradient >10 mmHg (p = 0.007) and CoA diameter <3 mm (p = 0.013). CONCLUSIONS The outcomes of BA for native CoA in neonates and infants with CHF remain poor. The incidence of recoarctation is high in neonates and patients whose post-BA systolic pressure gradient is >10 mmHg or whose CoA diameter is <3 mm.

RNA silencing targeting PIN (protein inhibitor of neuronal nitric oxide synthase) attenuates the development of hypertension in young spontaneously hypertensive rats

Nitric oxide (NO) deficiency contributes to hypertension. We previously showed that neuronal nitric oxide synthase (nNOS) was involved in hypertension and kidney damage in spontaneously hypertensive rats (SHRs). The protein inhibitor of nNOS (PIN) has been reported to inhibit activity of nNOS.Thus, we tested whether increased PIN in the kidney results in hypertension and whether small interfering RNA (siRNA) targeting PIN attenuates hypertension in SHRs. Four-week-old male SHRs were assigned into three groups (n = 6-7/group): SHR; SHR + PIN, SHR that received siRNA targeting PIN; and SHR + NC, SHR treated with random negative control siRNA. Rats were sacrificed at 12 weeks of age. PIN protein expression was inhibited considerably when PIN siRNA was transfected into NRK52E cells (90% siRNA at 1 nM). The increases of BP were attenuated by siRNA targeting PIN in 12-week-old SHRs. Immunostaining of nNOS-α and total nNOS was greater in SHR + PIN group than SHR. Moreover, renal superoxide production and 8-hydroxydeoxyguanosine (8-OHdG) staining were more decreased in the SHR + PIN group than SHRs. We conclude that PIN siRNA reduced PIN expression in vitro and in vivo. PIN siRNA therapy attenuates hypertension in SHRs at 12 weeks of age. Our results suggest that PIN is involved in the development of hypertension.

Impact of extracorporeal membrane oxygenation support on clinical outcome of pediatric patients with acute cardiopulmonary failure: a single-center experience.

Background: Conventional therapy against acute pediatric cardiopulmonary failure (APCPF) caused by a variety of disease entities remains unsatisfactory with extremely high morbidity and mortality. For refractory APCPF, extracorporeal membrane oxygenation (ECMO) is one of the last resorts. Methods: In this study, the in-hospital outcomes of pediatric patients with refractory APCPF receiving ECMO support were reviewed. Results: Between August 2006 and May 2011, a single-center cohort study was performed in pediatric patients who required ECMO support due to cardiogenic shock or severe hypoxemia. A total of 22 patients with mean age of 7.0 ± 6.3 years received ECMO (male = 11; female = 11). The indications included acute fulminant myocarditis (AFM) (n = 6), congenital diaphragmatic hernia (CDH) (n = 3), acute respiratory distress syndrome (ARDS) (n = 6), enterovirus 71 (n = 3), viral sepsis (n = 2), refractory ventricular fibrillation due to long QT syndrome (n = 1), and pulmonary edema with brain herniation (n = 1). Eighteen patients received veno-arterial (VA) mode ECMO, while another four patients undertook the veno-venous (VV) mode. The duration of ECMO use and hospitalization were 6.1 ± 3.1 and 24.4 ± 19.4 days, respectively. The survival rate in patients with AFM was 100% (n = 6). Successful ECMO weaning with uneventful discharge from hospital was noted in 14 (63.6%) patients, whereas in-hospital mortality despite successful ECMO weaning occurred in 5 patients (22.7%). Failure in ECMO weaning and in-hospital death was noted in 3 patients (13.6%). Conclusions: ECMO resuscitation is an effective strategy in the clinical setting of APCPF.