Eculizumab for paediatric patients with atypical haemolytic uraemic syndrome: full dataset analysis of post-marketing surveillance in Japan.

BACKGROUND: Eculizumab was approved for atypical haemolytic uraemic syndrome (aHUS) in Japan in 2013. Post-marketing surveillance (PMS) was mandated by regulatory authorities to assess the safety and effectiveness of eculizumab in patients with aHUS in a real-world setting. METHODS: Paediatric patients in the PMS cohort who were <18 years of age at the first administration of eculizumab and diagnosed with aHUS [excluding Shiga toxin-producing Escherichia coli HUS, thrombotic thrombocytopaenic purpura and secondary thrombotic microangiopathy (TMA)] were included in the effectiveness and safety analysis. Clinical endpoints of effectiveness [complete TMA response, TMA event-free status, platelet (PLT) count and lactate dehydrogenase (LDH) normalization, serum creatinine (sCr) decrease and estimated glomerular filtration rate (eGFR) improvement] were analysed in patients treated with at least one dose of eculizumab. Serious adverse events (SAEs) were also evaluated. RESULTS: A total of 40 paediatric patients (median age 5 years) were included. The median eculizumab treatment duration was 66 weeks. PLT count, LDH and eGFR significantly improved at 10 days post-treatment. Complete TMA response, haematologic normalization, sCr decrease, eGFR improvement and TMA event-free status were achieved by 73.3%, 73.3%, 70.0%, 78.3% and 77.5% of patients, respectively. Discontinuation criteria were met by 18 patients: 13 patients maintained treatment discontinuation at the end of observation and 5 patients, including 1 patient with aHUS relapse, continued the treatment but extended the treatment interval. During eculizumab treatment, 59 SAEs (0.66/person-year) were reported. Although four deaths were reported, none of them were related to eculizumab. CONCLUSION: Eculizumab was well tolerated and effective for paediatric patients with aHUS in the real-world setting in Japan.

Intrarenal renin-angiotensin system activation and macrophage infiltrations in pediatric chronic glomerulonephritis.

BACKGROUND: The current study tested the hypothesis that urinary angiotensinogen (UAGT) and urinary monocyte chemoattractant protein-1 (UMCP-1) levels provide a specific index of intrarenal renin-angiotensin system (RAS) status and the degree of infiltration of macrophages associated with RAS blockade and immunosuppressant treatment in pediatric patients with chronic glomerulonephritis. METHODS: We measured baseline UAGT and UMCP-1 levels to examine the correlation between glomerular injury in 48 pediatric chronic glomerulonephritis patients before treatment. Furthermore, we performed immunohistochemical analysis of angiotensinogen (AGT) and CD68 in 27 pediatric chronic glomerulonephritis patients treated with RAS blockades and immunosuppressants for 2 years. Finally, we examined the effects of angiotensin II (Ang II) on monocyte chemoattractant protein-1 (MCP-1) expression in cultured human mesangial cells (MCs). RESULTS: Baseline UAGT and UMCP-1 levels positively correlated with urinary protein levels, scores for mesangial hypercellularity, rate of crescentic formation, and expression levels of AGT and CD68 in renal tissues (p < 0.05). UAGT and UMCP-1 levels were significantly decreased after RAS blockade and immunosuppressant treatment (p < 0.01), which was accompanied by AGT and CD68 (p < 0.01), as well as the magnitude of glomerular injury. Cultured human MCs showed increased MCP-1 messenger ribonucleic acid and protein levels after Ang II treatment (p < 0.01). CONCLUSIONS: The data indicates that UAGT and UMCP-1 are useful biomarkers of the degree of glomerular injury during RAS blockade and immunosuppressant treatment in pediatric patients with chronic glomerulonephritis.

Updating the International IgA Nephropathy Prediction Tool for use in children.

Although IgA nephropathy (IgAN) is a common cause of glomerulonephritis in children, the absence of a method to predict disease progression limits personalized risk-based treatment decisions. The adult International IgAN Prediction Tool comprises two validated Cox survival models that predict a 50% decline in estimated glomerular filtration rate (eGFR) or end stage kidney disease (ESKD) using clinical risk factors and Oxford MEST histology scores. Here, we updated the Prediction Tool for use in children using a multiethnic international cohort of 1,060 children with IgAN followed into adulthood. The updated pediatric Prediction Tool had better model fit than the original adult tool with lower Akaike Information Criterion, higher R2D and similar C-statistics. However, calibration showed very poor agreement between predicted and observed risks likely due to the observed disease trajectory in children. Therefore, the Tool was updated using a secondary outcome of a 30% reduction in eGFR or ESKD, resulting in better R2D (30.3%/22.2%) and similar C-statistics (0.74/0.68) compared to the adult tool but with good calibration. The trajectory of eGFR over time in children differed from adults being highly non-linear with an increase until 18 years old followed by a linear decline similar to that of adults. A higher predicted risk was associated with a smaller increase in eGFR followed by a more rapid decline, suggesting that children at risk of a 30% decrease in eGFR will eventually experience a larger 50% decrease in eGFR when followed into adulthood. As such, these two outcomes are analogous between pediatric and adult Prediction Tools. Thus, our pediatric Prediction Tool can accurately predict the risk of a 30% decline in eGFR or ESKD in children with IgAN.

Once-daily, subcutaneous vosoritide therapy in children with achondroplasia: a randomised, double-blind, phase 3, placebo-controlled, multicentre trial.

BACKGROUND: There are no effective therapies for achondroplasia. An open-label study suggested that vosoritide administration might increase growth velocity in children with achondroplasia. This phase 3 trial was designed to further assess these preliminary findings. METHODS: This randomised, double-blind, phase 3, placebo-controlled, multicentre trial compared once-daily subcutaneous administration of vosoritide with placebo in children with achondroplasia. The trial was done in hospitals at 24 sites in seven countries (Australia, Germany, Japan, Spain, Turkey, the USA, and the UK). Eligible patients had a clinical diagnosis of achondroplasia, were ambulatory, had participated for 6 months in a baseline growth study and were aged 5 to less than 18 years at enrolment. Randomisation was done by means of a voice or web-response system, stratified according to sex and Tanner stage. Participants, investigators, and trial sponsor were masked to group assignment. Participants received either vosoritide 15·0 µg/kg or placebo, as allocated, for the duration of the 52-week treatment period administered by daily subcutaneous injections in their homes by trained caregivers. The primary endpoint was change from baseline in mean annualised growth velocity at 52 weeks in treated patients as compared with controls. All randomly assigned patients were included in the efficacy analyses (n=121). All patients who received one dose of vosoritide or placebo (n=121) were included in the safety analyses. The trial is complete and is registered, with EudraCT, number, 2015-003836-11. FINDINGS: All participants were recruited from Dec 12, 2016, to Nov 7, 2018, with 60 assigned to receive vosoritide and 61 to receive placebo. Of 124 patients screened for eligibility, 121 patients were randomly assigned, and 119 patients completed the 52-week trial. The adjusted mean difference in annualised growth velocity between patients in the vosoritide group and placebo group was 1·57 cm/year in favour of vosoritide (95% CI [1·22-1·93]; two-sided p<0·0001). A total of 119 patients had at least one adverse event; vosoritide group, 59 (98%), and placebo group, 60 (98%). None of the serious adverse events were considered to be treatment related and no deaths occurred. INTERPRETATION: Vosoritide is an effective treatment to increase growth in children with achondroplasia. It is not known whether final adult height will be increased, or what the harms of long-term therapy might be. FUNDING: BioMarin Pharmaceutical.

Biallelic variants/mutations of IL1RAP in patients with steroid-sensitive nephrotic syndrome.

Nephrotic syndrome (NS) is a renal disease characterized by severe proteinuria and hypoproteinemia. Although several single-gene mutations have been associated with steroid-resistant NS, causative genes for steroid-sensitive NS (SSNS) have not been clarified. While seeking to identify causative genes associated with SSNS by whole-exome sequencing, we found compound heterozygous variants/mutations (c.524T>C; p.I175T and c.662G>A; p.R221H) of the interleukin-1 receptor accessory protein (IL1RAP) gene in two siblings with SSNS. The siblings' parents are healthy, and each parent carries a different heterozygous IL1RAP variant/mutation. Since IL1RAP is a critical subunit of the functional interleukin-1 receptor (IL-1R), we investigated the effect of these variants on IL-1R subunit function. When stimulated with IL-1ß, peripheral blood mononuclear cells from the siblings with SSNS produced markedly lower levels of cytokines compared with cells from healthy family members. Moreover, IL-1R with a variant IL1RAP subunit, reconstituted on a hematopoietic cell line, had impaired binding ability and low reactivity to IL-1ß. Thus, the amino acid substitutions in IL1RAP found in these NS patients are dysfunctional variants/mutations. Furthermore, in the kidney of Il1rap-/- mice, the number of myeloid-derived suppressor cells, which require IL-1ß for their differentiation, was markedly reduced although these mice did not show significantly increased proteinuria in acute nephrotic injury with lipopolysaccharide treatment. Together, these results identify two IL1RAP variants/mutations in humans for the first time and suggest that IL1RAP might be a causative gene for familial NS.

Neonatal rebound hyperkalemia associated with ritodrine alone: a case report.

BACKGROUND: Betamimetics have been used for tocolysis extensively in the past, and one of them, ritodrine is widely used in Japan. Various adverse events have been reported for this agent, including newborn hypoglycemia and hypokalemia, as well as maternal hypokalemia and rebound hyperkalemia; however, cases of neonatal rebound hyperkalemia are not described in the literature. CASE PRESENTATION: A male infant born at 36 weeks of gestation by cesarean section at a local maternity clinic suddenly entered cardiopulmonary arrest with ventricular tachycardia and fibrillation due to hyperkalemia (K+, 8.7 mmol/L). No monitoring, examination of blood electrolyte levels, or infusions had been performed prior to this event. Maternal infusion of ritodrine (maximum dose, 170 µg/min) had been performed for 7 weeks prior to cesarean section. After resuscitation combined with calcium gluconate, the infant died at 4 months old due to serious respiratory failure accompanied by acute lung injury following shock. No cause of hyperkalemia other than rebound hyperkalemia associated with ritodrine was identified. CONCLUSIONS: This case report serves as a warning regarding the potential risk of neonatal rebound hyperkalemia in association with maternal long-term ritodrine administration.

(Pro)renin receptor promotes crescent formation via the ERK1/2 and Wnt/ß-catenin pathways in glomerulonephritis.

(Pro)renin receptor [(P)RR] has multiple functions, but its regulation and role in the pathogenesis in glomerulonephritis (GN) are poorly defined. The aims of the present study were to determine the effects of direct renin inhibition (DRI) and demonstrate the role of (P)RR on the progression of crescentic GN. The anti-glomerular basement membrane nephritis rat model developed progressive proteinuria (83.64 ± 10.49 mg/day) and glomerular crescent formation (percent glomerular crescent: 62.1 ± 2.3%) accompanied by increased macrophage infiltration and glomerular expression of monocyte chemoattractant protein (MCP)-1, (P)RR, phospho-extracellular signal-regulated kinase (ERK)1/2, Wnt4, and active ß-catenin. Treatment with DRI ameliorated proteinuria (20.33 ± 5.88 mg/day) and markedly reduced glomerular crescent formation (20.9 ± 2.6%), induction of macrophage infiltration, (P)RR, phospho-ERK1/2, Wnt4, and active ß-catenin. Furthermore, primary cultured parietal epithelial cells stimulated by recombinant prorenin showed significant increases in cell proliferation. Notably, while the ERK1/2 inhibitor PD98059 or (P)RR-specific siRNA treatment abolished the elevation in cell proliferation, DRI treatment did not abrogate this elevation. Moreover, cultured mesangial cells showed an increase in prorenin-induced MCP-1 expression. Interestingly, (P)RR or Wnt4-specific siRNA treatment or the ß-catenin antagonist XAV939 inhibited the elevation of MCP-1 expression, whereas DRI did not. These results suggest that (P)RR regulates glomerular crescent formation via the ERK1/2 signaling and Wnt/ß-catenin pathways during the course of anti-glomerular basement membrane nephritis and that DRI mitigates the progression of crescentic GN through the reduction of (P)RR expression but not inhibition of prorenin binding to (P)RR.

Reduction in urinary angiotensinogen levels and improvement of proteinuria by renin-angiotensin system blockade in pediatric chronic kidney disease patients with very low birth weight.

BACKGROUND: Children with low birth weight (LBW) have an increased risk of developing chronic kidney disease (CKD), and no effective strategies have been established to prevent the progression of CKD in these patients. Urinary angiotensinogen (UAGT) may represent a useful marker of intrarenal renin-angiotensin system (RAS) activation, which has been suggested to play a critical role in the development of hypertension and CKD. Herein, we conducted a prospective study to determine whether RAS blockade is beneficial for suppressing the progression of CKD in children with LBW, using UAGT as a surrogate marker of renal impairment. METHODS: Nine children with CKD (stages: 1-2) who had very low birth weight (VLBW; < 1500 g) were started on RAS blockade with candesartan. We measured blood pressure and laboratory parameters, including urinary concentrations of angiotensinogen, protein, albumin, creatinine (Cr), and estimated glomerular filtration rate (eGFR), before and after candesartan treatment. RESULTS: Birth weight was 712 g (range, 536-800 g). Age at evaluation was 11.6 years (range, 10.3-15.6 years). After candesartan treatment for 47.6 ± 25.0 months, the UAGT to urinary Cr ratio decreased from 61.9 ± 44.7 to 16.8 ± 14.4 µg/g (p = 0.015). The urinary protein to Cr and albumin to Cr ratios also decreased (p = 0.008 and p = 0.012, respectively), whereas there was no significant change in eGFR. CONCLUSIONS: RAS blockade reduced UAGT levels and improved proteinuria/albuminuria in children with CKD who had VLBW. Suppression of intrarenal RAS activity may slow the progression of CKD in children with LBW.

A nationwide cross-sectional analysis of thrombotic microangiopathy in the Japan Renal Biopsy Registry (J-RBR).

BACKGROUND: There have been only a few large-scale cohort studies that have reviewed accumulated cases of thrombotic microangiopathy (TMA). The aim of this study was to collect and analyze TMA cases based on the renal biopsy, as a nationwide survey in Japan. METHODS: In this cross-sectional study, large nationwide data from the Japan Renal Biopsy Registry (J-RBR) were used. Among the patients registered in the J-RBR online system from July 2007 to July 2017, TMA cases were extracted and epidemiological data and clinical findings were investigated. RESULTS: Out of the 38,495 patients enrolled in a period of 10 years, 152 (0.39%) cases had been diagnosed with TMA. The patient age was widely distributed, including 9.2%, 66.4%, and 24.3% for children, adults, and the elderly, respectively. There were various causes of TMA. Among them, hemolytic uremic syndrome (HUS)/thrombotic thrombocytopenic purpura (TTP) (16.4%), connective tissue disease (CTD)-related (17.1%), and drug-induced (16.4%) were frequently observed. The background factors of TMA were different in children and adults. In a comparison between groups consisting of HUS/TTP, CTD-related, and drug-induced, the HUS/TTP group was significantly younger (p = 0.01), and the drug-induced TMA group tended to have a high urinary protein positive rate (p = 0.05). A comparative analysis according to the age group showed significantly higher serum creatinine levels in the elderly (p < 0.01). CONCLUSION: This is the first report of epidemiological and clinical data of biopsy-proven TMA in Japan. The characteristics of TMA with diversity based on the underlying disease and age group were reported.

Enhanced angiotensinogen expression in neonates during kidney development.

BACKGROUND: We recently demonstrated that preterm neonates have higher urinary angiotensinogen (AGT) levels than full-term neonates. Here, we tested the hypothesis that enhanced neonatal AGT expression is associated with intrarenal renin-angiotensin system (RAS) status during kidney development. METHODS: We prospectively recruited neonates born at our hospital and healthy children with minor glomerular abnormalities between April 2013 and March 2017. We measured neonatal plasma and urinary AGT levels at birth and 1 year later and assessed renal AGT expression in kidney tissues from neonates and healthy children using immunohistochemical (IHC) analysis. RESULTS: Fifty-four neonates and eight children were enrolled. Although there were no changes in plasma AGT levels, urinary AGT levels were significantly decreased 1 year after birth. Urinary AGT levels at birth were inversely correlated with gestational age, and urinary AGT levels at birth and 1 year later were inversely correlated with estimated glomerular filtration rate 1 year after birth. IHC analysis showed that renal AGT expression in neonates was higher than that in healthy children and inversely correlated with gestational age. CONCLUSIONS: Enhanced AGT expression and urinary AGT excretion may reflect intrarenal RAS activation associated with kidney development in utero.

Safety and effectiveness of eculizumab for pediatric patients with atypical hemolytic-uremic syndrome in Japan: interim analysis of post-marketing surveillance.

BACKGROUND: In 2013, eculizumab was approved for treatment of the atypical hemolytic-uremic syndrome (aHUS) in Japan, which was defined as a thrombotic microangiopathy (TMA) excluding Shiga toxin-producing Escherichia coli-HUS and thrombotic thrombocytopenic purpura. Simultaneously, post-marketing surveillance was started to assess its safety and effectiveness. In 2016, Japanese clinical guide redefined terms to limit the use of "aHUS" to complement-mediated HUS only. Accordingly, TMA with other causes was defined as secondary TMA. Here we report the interim analysis of post-marketing surveillance of pediatric patients with aHUS and secondary TMA. METHODS: Pediatric patients treated with eculizumab from approval to 15 March 2017 were included in this observational real-world study. Clinical endpoints of effectiveness were TMA event-free status, complete TMA response, platelet count normalization, and improvement of estimated glomerular filtration rate (eGFR). Adverse reactions to eculizumab were also analyzed. RESULTS: In 27 pediatric patients with aHUS, median age at diagnosis was 4 years. Complement genes' variants were detected in 14 of 21 patients (66.7%). Median time from diagnosis to eculizumab initiation was 2.0 days. TMA event-free status, complete TMA response, platelet normalization, and improvement in eGFR were achieved in 85.2, 36.4, 78.3, and 75.0% of patients, respectively. Three patients with aHUS died. Twenty-four and 10 adverse reactions were reported in 31 aHUS patients and 17 secondary TMA patients, respectively; however, no eculizumab-related death or meningococcal infection was reported. CONCLUSIONS: This interim analysis confirmed that eculizumab is well-tolerated and effective for Japanese pediatric patients with aHUS in a real-world setting.

Safety and effectiveness of eculizumab for adult patients with atypical hemolytic-uremic syndrome in Japan: interim analysis of post-marketing surveillance.

BACKGROUND: Eculizumab has been available for the treatment of atypical hemolytic-uremic syndrome (aHUS) in Japan since 2013. To assess safety and effectiveness of eculizumab in adult aHUS patients in the real-life setting, we performed interim analysis of a post-marketing surveillance mandated by Japanese regulations. METHODS: This study enrolled any patient who was diagnosed with TMA excluding Shiga toxin-producing Escherichia coli-HUS or thrombotic thrombocytopenic purpura based on Japanese clinical guide published in 2013 as inclusion criteria and treated with eculizumab. Although the term aHUS was redefined to denote only complement-mediated HUS in the guide revised in 2016, the patients with TMA caused by other causes (secondary TMA) were included. Patient outcomes and safety were evaluated at 6 months, 12 months, and annually thereafter. RESULTS: Thirty-three patients with aHUS and 27 patients with secondary TMA were enrolled. Median treatment duration of aHUS was 24weeks. Complement genes variants were detected in 11 of 18 patients with aHUS (61.1%). Among the 29 aHUS patients with available baseline data, platelet count (PLT), lactic dehydrogenase and serum creatinine (SCr) improved within 1-month after eculizumab initiation. TMA event-free status, complete TMA response, PLT normalization, and SCr decrease were achieved in 67.9% (19/28), 27.8% (5/18), 56.5% (13/23), and 57.1% (16/28) of patients, respectively. Thirty-three and 11 adverse reactions were observed in patients with aHUS (13/33 patients) and secondary TMA (6/27 patients), respectively. CONCLUSIONS: This interim analysis confirmed the acceptable safety profile and effectiveness of eculizumab for Japanese adult aHUS patients in real-world settings.

Biallelic Mutations in Nuclear Pore Complex Subunit NUP107 Cause Early-Childhood-Onset Steroid-Resistant Nephrotic Syndrome.

The nuclear pore complex (NPC) is a huge protein complex embedded in the nuclear envelope. It has central functions in nucleocytoplasmic transport, nuclear framework, and gene regulation. Nucleoporin 107 kDa (NUP107) is a component of the NPC central scaffold and is an essential protein in all eukaryotic cells. Here, we report on biallelic NUP107 mutations in nine affected individuals who are from five unrelated families and show early-onset steroid-resistant nephrotic syndrome (SRNS). These individuals have pathologically focal segmental glomerulosclerosis, a condition that leads to end-stage renal disease with high frequency. NUP107 is ubiquitously expressed, including in glomerular podocytes. Three of four NUP107 mutations detected in the affected individuals hamper NUP107 binding to NUP133 (nucleoporin 133 kDa) and NUP107 incorporation into NPCs in vitro. Zebrafish with nup107 knockdown generated by morpholino oligonucleotides displayed hypoplastic glomerulus structures and abnormal podocyte foot processes, thereby mimicking the pathological changes seen in the kidneys of the SRNS individuals with NUP107 mutations. Considering the unique properties of the podocyte (highly differentiated foot-process architecture and slit membrane and the inability to regenerate), we propose a "podocyte-injury model" as the pathomechanism for SRNS due to biallelic NUP107 mutations.

A rare male patient with classic Rett syndrome caused by MeCP2_e1 mutation.

Rett syndrome (RTT) is a severe neurodevelopmental disorder typically affecting females. It is mainly caused by loss-of-function mutations that affect the coding sequence of exon 3 or 4 of methyl-CpG-binding protein 2 (MECP2). Severe neonatal encephalopathy resulting in death before the age of 2 years is the most common phenotype observed in males affected by a pathogenic MECP2 variant. Mutations in MECP2 exon 1 affecting the MeCP2_e1 isoform are relatively rare causes of RTT in females, and only one case of a male patient with MECP2-related severe neonatal encephalopathy caused by a mutation in MECP2 exon 1 has been reported. This is the first reported case of a male with classic RTT caused by a 5-bp duplication in the open-reading frame of MECP2 exon 1 (NM_001110792.1:c.23_27dup) that introduced a premature stop codon [p.(Ser10Argfs*36)] in the MeCP2_e1 isoform, which has been reported in one female patient with classic RTT. Therefore, both males and females displaying at least some type of MeCP2_e1 mutation may exhibit the classic RTT phenotype.

Effects of the selective chymase inhibitor TEI-F00806 on the intrarenal renin-angiotensin system in salt-treated angiotensin I-infused hypertensive mice.

NEW FINDINGS: What is the central question of this study? Can chymase inhibition prevent angiotensin I-induced hypertension through inhibiting the conversion of angiotensin I to angiotensin II in the kidney? What is the main finding and its importance? Treatment with TEI-F00806 decreased angiotensin II content of the kidney, renal cortical angiotensinogen protein levels and chymase mRNA expression, and attenuated the development of hypertension. ABSTRACT: The effects of the selective chymase inhibitor TEI-F00806 were examined on angiotensin I (Ang I)-induced hypertension and intrarenal angiotensin II (Ang II) production in salt-treated mice. Twelve-week-old C57BL male mice were given a high-salt diet (4% NaCl + saline (0.9% NaCl)), and divided into three groups: (1) sham + vehicle (5% acetic acid in saline), (2) Ang I (1 µg kg-1  min-1 , s.c.) + vehicle, and (3) Ang I + TEI-F00806 (100 mg kg-1  day-1 , p.o.) (n = 8-10 per group). Systolic blood pressure was measured weekly using a tail-cuff method. Kidney Ang II content was measured by radioimmunoassay. Chronic infusion of Ang I resulted in the development of hypertension (P < 0.001), and augmented intrarenal chymase gene expression (P < 0.05), angiotensinogen protein level (P < 0.001) and Ang II content (P < 0.01) in salt-treated mice. Treatment with TEI-F00806 attenuated the development of hypertension (P < 0.001) and decreased Ang II content of the kidney (P < 0.05), which was associated with reductions in renal cortical angiotensinogen protein levels (P < 0.001) and chymase mRNA expression (P < 0.05). These data suggest that a chymase inhibitor decreases intrarenal renin-angiotensin activity, thereby reducing salt-dependent hypertension.

Pulmonary Artery Wall Thickness Assessed by Optical Coherence Tomography Correlates With Pulmonary Hemodynamics in Children With Congenital Heart Disease.

BACKGROUND: Pulmonary arterial (PA) wall thickening evaluated by optical coherence tomography (OCT) has been reported in adults with PA hypertension. The purpose of this study was to evaluate the feasibility of OCT for preoperative assessment of the PA wall in children with congenital heart disease (CHD). Methods and Results: Participants comprised 39 patients with ventricular septal defect, atrial septal defect, or patent ductus arteriosus. Attempts were made to evaluate vessels of various diameters using OCT. Clearly observed vessels that were optimal for evaluation were selected and classified into 4 subgroups by diameter of the lumen. Optimal depiction was obtained in 80 of 156 vessels in total, and 25 (64.1%), 34 (87.1%), 17 (43.6%), and 4 vessels (10.3%) in each of the 1.0-<2.0 mm, 2.0-<3.0 mm, 3.0-<4.0 mm, and 4.0-5.0 mm subgroups, respectively. Arterial walls in the 2.0-<3.0 mm subgroup were the most frequently delineated, and wall thickness correlated significantly with mean PA pressure, pulmonary vascular resistance index, pulmonary-to-systemic flow ratio, and PA capacitance index (r=0.56, 0.52, 0.37, and -0.49, respectively). The 3-layered appearance was delineated in 29 of 80 vessels (36.2%). This feature had no significant correlation with pulmonary hemodynamics. CONCLUSIONS: OCT represents a promising tool for evaluating the PA wall in children with CHD.

Pulmonary annular motion velocity reflects right ventricular outflow tract function in children with surgically repaired congenital heart disease.

Right ventricular (RV) dysfunction is generally evaluated using analyses of tricuspid annular motion. However, it represents only one aspect of RV performance. Whether measuring pulmonary annular motion velocity could serve as a novel way to evaluate global RV and/or RV outflow tract (RVOT) performance in pediatric congenital heart disease (CHD) patients with surgically repaired RVOT was evaluated. In this prospective study, tissue Doppler-derived pulmonary annular motion velocity was measured in children (aged 2-5 years) with RVOT reconstruction (RVOTR group, n = 48) and age-matched healthy children (Control, n = 60). The types of RVOTR procedures were as follows: pulmonary valve-sparing procedure (PVS, n = 7); transannular patch with monocusp valve reconstruction (TAP, n = 29); and RV-to-PA conduit reconstruction using a pericardial valve with expanded polytetrafluoroethylene conduit (Rastelli, n = 12). Pulmonary annular motion velocity waveforms comprised systolic bimodal (s1' and s2') and diastolic e' and a' waves in all participants. The peak velocities of s1', s2', e', and a' were significantly lower in the RVOTR group than in the control group (all p < 0.0001). Furthermore, these parameters depended significantly on the type of surgical procedure. The peak velocities of s1', s2', and e' had significant correlations with RVOT ejection fraction (RVOT-EF) (r = 0.56, 0.49, and 0.34, respectively), and RVOT fractional shortening (RVOT-FS) (r = 0.72, 0.55, and 0.41, respectively), although there were no significant correlations between pulmonary annular motion and global RV function, including RV ejection fraction (RVEF) and RV fractional area change (RVFAC) in the assessment of all RVOTR group patients. The pulmonary annular motion parameters in the PVS group had significant correlations with both global RV and RVOT performance. The TAP group showed significant correlations between RVOT function and pulmonary annular motion. The Rastelli group showed almost no significant correlations between RV/RVOT function and tissue Doppler parameters. Pulmonary annular motion velocity is a simple, rapid, reproducible, and useful method of assessing RVOT function in children with surgically repaired CHD.

Temporal Sequential Pattern of Right Ventricular Free Wall Contraction in Normal Children.

BACKGROUND: The temporal sequence of right ventricular (RV) deformation is related to RV dysfunction. The sequence of RV free wall contraction was investigated.Methods and Results:In this prospective study, strain profiles using speckle-tracking echocardiography and tissue Doppler-derived pulmonary and tricuspid annular motion were assessed in 60 normal children. Circumferential RV free wall strain of 3 individual segments (anterior, lateral, and inferior) was evaluated. Longitudinal strain was assessed in 3 individual segments (RV outflow tract [RVOT], apical, and RV inflow tract [RVIT]). The isovolumetric contraction time (ICT) and the time interval between the onset of the QRS wave to the peak s' wave were measured for pulmonary and tricuspid annular motion velocities. The time to peak circumferential strain was significantly lower in the anterior than in the lateral and inferior segments (339.1±19.5, 358.3±21.8, and 366.6±22.4 ms, respectively; P<0.0001). Longitudinal deformation of the RVOT segment occurred before the apical and RVIT segments (351.8±23.1, 366.3±20.1, and 369.2±21.3 ms, respectively; P<0.0001). The ICT and the time to peak s' were significantly shorter in pulmonary than in tricuspid annular motion (49.4±10.1 vs 58.0±13.2 ms; and 104.7±12.2 vs. 160.5±27.1 ms; P<0.0001 for each). CONCLUSIONS: Longitudinal deformation of RVOT precedes RVIT. Circumferential deformation occurs in the anterior segment before the lateral and posterior segments. The presence of mechanical time heterogeneity appears important for RV performance.

Role of the intrarenal renin-angiotensin system in the progression of renal disease.

The intrarenal renin-angiotensin system (RAS) has many well-documented pathophysiologic functions in both blood pressure regulation and renal disease development. Angiotensin II (Ang II) is the major bioactive product of the RAS. It induces inflammation, renal cell growth, mitogenesis, apoptosis, migration, and differentiation. In addition, Ang II regulates the gene expression of bioactive substances and activates multiple intracellular signaling pathways that are involved in renal damage. Activation of the Ang II type 1 (AT1) receptor pathway results in the production of proinflammatory mediators, intracellular formation of reactive oxygen species, cell proliferation, and extracellular matrix synthesis, which in turn facilities renal injury. Involvement of angiotensinogen (AGT) in intrarenal RAS activation and development of renal disease has previously been reported. Moreover, studies have demonstrated that the urinary excretion rates of AGT provide a specific index of the intrarenal RAS status. Enhanced intrarenal AGT levels have been observed in experimental models of renal disease, supporting the concept that AGT plays an important role in the development and progression of renal disease. In this review, we focus on the role of intrarenal RAS activation in the pathophysiology of renal disease. Additionally, we explored the potential of urinary AGT as a novel biomarker of intrarenal RAS status in renal disease.

(Pro)renin and (pro)renin receptor expression during kidney development in neonates.

Although a recent study demonstrated that the (pro)renin receptor ((P)RR) was highly expressed in the developing kidney during the mouse embryonic development, the mechanism by which (P)RR supports renal development in humans is not fully understood. In this study, we examined the plasma levels of (pro)renin and soluble (P)RR (s(P)RR) in cord blood and neonates as well as (P)RR expression in human kidney tissues. Samples were collected from 57 preterm and 67 full-term human neonates. (Pro)renin and s(P)RR levels were measured using enzyme-linked immunosorbent assays. Additionally, we performed an immunohistochemical (IHC) analysis of kidney tissues from neonates and minor glomerular abnormalities in order to assess (P)RR expression in the kidney. Plasma (pro)renin and s(P)RR levels in cord blood were significantly higher in preterm neonates than in full-term neonates. Four weeks after birth, these differences were no longer evident for either plasma (pro)renin or s(P)RR levels between the two groups. Importantly, plasma (pro)renin and s(P)RR levels in cord blood were inversely correlated with gestational age. Furthermore, IHC indicated that renal expression levels of (P)RR in neonates were stronger than those in minor glomerular abnormalities. CONCLUSION: (P)RR may play a pivotal role in prenatal renal development in humans. What is Known: • Renal renin-angiotensin system (RAS) has several pathophysiologic functions not only in blood pressure regulation but also in pediatric renal disease. • Renal RAS activation plays a key role of renal development during gestation. What is New : • Plasma (pro)renin and soluble (pro)renin receptor (s(P)RR) levels in cord blood were significantly higher in preterm neonates than in full-term neonates. • Immunohistochemical analysis of kidney tissue indicated that renal expression levels of (P)RR in neonates were stronger than in minor glomerular abnormalities.