Hydrogen-rich water reduced oxidative stress and renal fibrosis in rats with unilateral ureteral obstruction.

BACKGROUND: Congenital obstructive nephropathy (CKD) is commonly implicated in the pathophysiology of chronic kidney disease occurring in the pediatric and adolescent age groups and the release of reactive oxygen species contribute to the worsening of renal fibrosis. Molecular hydrogen (H2) protects against tissue injury by reducing oxidative stress. We evaluated the efficacy of oral H2-rich water (HW) intake in preventing unilateral ureteral obstruction (UUO)-induced renal injury in rats. METHODS: Male Sprague-Dawley UUO or control rats were administered with distilled water (DW) or HW for 2 weeks post-surgery. Histopathological and immunohistochemical analyses of kidney samples were performed. RESULTS: Histological changes were not apparent in the sham-operated kidneys. However, UUO kidneys were found to have widened interstitial spaces and tubular dilatation. Compared with the UUO + DW group, HW administration attenuated tubulointerstitial injury and reduced interstitial fibrotic area, causing a substantial decline in the frequency of α-SMA-, ED-1-, and TGF-ß1-positive cells in the UUO + HW group. The decrease in the klotho mRNA expression in the UUO + HW group was less pronounced than that in the UUO + DW group. CONCLUSION: Oral HW intake reduced oxidative stress and prevented interstitial fibrosis in UUO kidneys, potentially involving klotho in the underlying mechanism. IMPACT: Oral intake of hydrogen-rich water (HW) can reduce oxidative stress and suppress interstitial fibrosis in unilateral ureteral obstruction-induced renal injury in rats. This mechanism possibly involves klotho, which is known for its antiaging roles. The association between molecular hydrogen and klotho in renal fibrosis is well known; this is the first report on the association in a unilateral ureteral obstruction model. Drinking HW is a safe and convenient treatment for oxidative stress-induced pathologies, without side effects. As a prospect for future research, oral HW intake to treat oxidative stress may improve renal fibrosis in congenital obstructive nephropathy.

Positive effects of single-daily high-dose mizoribine therapy after cyclophosphamide in young children with steroid-dependent nephrotic syndrome.

BACKGROUND: Mizoribine (MZR) therapy after cyclophosphamide (CPM) therapy may be an attractive option in patients with steroid-dependent nephrotic syndrome (SDNS) for the purpose of maintaining remission. This is because CPM is administered only once due to its severe side effects such as gonadal toxicity. However, the long-term prognosis after the treatment regimen remains unknown. METHODS: We retrospectively analyzed the clinical course (median follow-up, 5.9 years) of 54 young children with SDNS (43 boys; age < 10 years) who had undergone 12-week CPM therapy. The patients were classified into two groups: group A, undergoing MZR therapy for > 12 months for maintaining remission after CPM therapy (N = 36), and group B, undergoing CPM monotherapy (N = 18). RESULTS: For 2 years after CPM therapy, 21 of the 36 group A patients were in sustained remission, whereas only 4 of the 18 group B patients had maintained remission (58% vs. 22%, p < 0.05). Furthermore, the rate of regression to SDNS after CPM was significantly lower in group A than in group B (6% vs. 39%, p < 0.05). At the last follow-up (mean age, 10.9 years), 27 of the 36 group A patients (75%) had not received any steroid-sparing agent after the treatment regimen. CONCLUSIONS: Single daily high-dose MZR therapy after CPM therapy may have positive outcomes in young children with SDNS in the long term.

Urinary angiotensinogen in pediatric urinary tract infection.

BACKGROUND: Urinary tract infection (UTI) is one of the most common diseases in children, and urinary angiotensinogen (U-AGT) is a new biomarker gathering attention in many renal diseases. U-AGT reflects intrarenal renin-angiotensin system (RAS) activity. We conducted a study to measure U-AGT in children <4 months old with UTI. METHODS: All children <4 months old who came to Toshima Hospital with fever between January 2015 and December 2015 were included. Patients were divided into a UTI group and a non-UTI group, and U-AGT was measured. RESULTS: Median U-AGT was higher in patients with UTI compared with patients without UTI: (0.56 ng/dL, range, 0.025-2.753 ng/dL vs 0.13 ng/dL, range, 0.008-1.697 ng/dL, respectively; P < 0.05). CONCLUSIONS: U-AGT is elevated in UTI patients, and RAS activation may contribute to renal injury caused by UTI.

Predictors of relapse and long-term outcome in children with steroid-dependent nephrotic syndrome after rituximab treatment.

BACKGROUND: In patients with complicated steroid-dependent nephrotic syndrome (SDNS), rituximab (RTX) followed by immunosuppressive agent (IS) can maintain remission without the use of prednisolone (PSL). However, available data on the predictive factors for relapse and the long-term outcome after this protocol are few. METHODS: We retrospectively analyzed 43 SDNS patients who were followed-up for a long time (>2 years, mean 5.4 years) after a single dose of RTX (375 mg/m2) from September 2007. After RTX, PSL was tapered off within 6 months; monotherapy with IS, such as cyclosporine or mycophenolate mofetil, was continued to prevent post-RTX relapse. For patients who achieved >12 months of PSL-free remission, IS was also tapered off. RESULTS: Thirty-nine patients (91 %) could discontinue PSL without relapses at a median of 154 days after the initial RTX. The first relapse of NS occurred in 39 patients (91 %) at a median of 586 days; additional RTX doses were administered in 28 patients (65 %). Kaplan-Meier analysis showed that shorter CD19 cell depletion (<150 days) and younger age at RTX initiation (<12.5 years) were significantly associated with high risk for first relapse after RTX (log rank p < 0.05). In multivariate analysis, mycophenolate mofetil therapy as maintenance IS after RTX was the only predicted risk factor for first relapse (hazard ratio 2.75; p = 0.027). At the last follow-up, IS was still used in 33 patients (77 %); treatment-free remission (>12 months) was achieved in only five patients (12 %). CONCLUSIONS: The introduction of RTX may not be necessarily associated with improved long-term outcome.

Impaired nephrogenesis in neonatal rats with oxygen-induced retinopathy.

BACKGROUND: Preterm neonates are born while nephrogenesis is ongoing, and are commonly exposed to factors in a hyperoxic environment that can impair renal development. Oxidative stress has also been implicated in the development of retinopathy of prematurity (ROP). The rat model of oxygen-induced retinopathy (OIR) is the most clinically relevant model of ROP because its biologic features closely resemble those of ROP in preterm infants. We investigated impaired renal development in a rat model of OIR. METHODS: Newborn Sprague-Dawley rats were maintained in either a normoxic (room air, 21% O2 ; control group) or a controlled hyperoxic (80% O2 ; OIR group) environment from birth to postnatal day (P) 12. All pups were then raised in room air from P12 to P19. RESULTS: The hyperoxic environment led to significantly higher urinary excretion of 8-hydroxy-2'-deoxyguanosine, a marker of oxidative DNA damage, and a reduction in nephrogenic zone width at P5 in OIR pups. Additionally, glomerular count was significantly reduced by 20% in the OIR group, and avascular and neovascular changes in the retina were observed only in the OIR group at P19. Messenger RNA levels of vascular endothelial growth factor-A (VEGF-A) and platelet-derived growth factor-ß, essential angiogenic cytokines for glomerulogenesis, in the renal cortex were significantly lower at P5 and significantly higher at P19 in the OIR group compared with controls. CONCLUSION: Renal impairment was caused by exposure to a hyperoxic environment during nephrogenesis, and the pathology of the impaired nephrogenesis in this OIR model reflects the characteristics of ROP observed in preterm infants.

Rapid recovery of coral communities from a mass bleaching event in the summer of 2016, observed in Amitori Bay, Iriomote Island, Japan.

Devastating bleaching of coral communities at Amitori Bay, Iriomote Island, Japan, occurred in 2016 during the third global mass bleaching event in 2014-2017. The present study documented changes in coral communities in Amitori Bay from just before until after the 2016 bleaching event (2016-2020), by measuring coral cover and recruitment at nine sites (with two additional sites in 2018) in the bay. Spawning rates of acroporid corals were also monitored from 2017 to 2019 by visual observation and using bundle collectors to observe how long the effect of bleaching persisted. Reductions of 64.7 and 89.5% from 2016 to 2017 were observed in cover and recruitment of all coral families, respectively. Coral cover of all coral families recovered to pre-bleaching levels by 2020 and recruitment in 2020 was about two times greater than the pre-bleaching level. These results mirrored those of acroporids. Spawning rates of Acropora corals increased significantly from 40.6% in 2017 to 90.0% in 2019. Recovery of coral cover 4 years after the severe bleaching event was likely related to regrowth of remnants and of surviving juveniles of < 5 cm. The sudden increase in recruitment was likely driven by a combination of larval supply from other populations, increased numbers of reproductive adults, increases in spawning rates, and increased larval retention in the bay due to wind conditions in 2020. This study suggests that coral communities as in Amitori Bay will be critical for local-scale community persistence, serving as both source and sink populations. Supplementary Information: The online version contains supplementary material available at 10.1007/s00227-022-04091-2.

An infant of 26 weeks gestation with congenital miliary tuberculosis complicated by chronic lung disease requiring CPAP was diagnosed on Day 104 of life: congenital tuberculosis was confirmed by detection of calcified ovaries in his mother.

INTRODUCTION: Early diagnosis of tuberculosis (TB) in infants is important but is commonly missed because the symptoms are often non-specific. CASE PRESENTATION: A Nepalese male infant born at 26 weeks gestation and weighing 1227 g (97th centile) was admitted to the neonatal intensive care unit (NICU) immediately after birth for the management of his prematurity. After extubation on Day 8, his oxygen saturation became unstable and he required nasal continuous positive airway pressure with oxygen for 3 months. On Day 104, further detailed evaluation was required because there was no improvement in his respiratory condition. A computed tomography (CT) scan demonstrated scattered miliary nodules in both lung fields. Acid-fast staining for the mycobacteria and TB polymerase chain reaction (PCR) of the sputum obtained directly by laryngeal aspiration confirmed Mycobacterium tuberculosis. On Day 105, he was therefore transferred to a tertiary care hospital for further intensive care. Pathology findings suggested placental involvement with TB owing to chronic endometrial infection. In addition, a maternal abdominal CT scan demonstrated bilateral calcified lesions in the ovaries. He completed antituberculous chemotherapy and was discharged 3 months later. At 18 months of age there are no sequelae and his development is almost normal. None of the infants or medical personnel who were exposed in the NICU developed secondary TB. CONCLUSION: In neonates with persistent respiratory distress, neonatologists should consider TB infection as a differential diagnosis. ABBREVIATIONS: CLD: chronic lung disease; CRP: C-reactive protein; CT: computed tomography; IGRA: interferon-γ release assay; IVF-ET: in vitro fertilisation-embryo transfer; N-CPAP: nasal continuous positive airway pressure; NICU: neonatal intensive care unit; PCR: polymerase chain reaction; PROM: premature rupture of membranes; TB: tuberculosis; WBC: white blood cells.

Protective Effects of Hydrogen-rich Water Intake on Renal Injury in Neonatal Rats with High Oxygen Loading.

Objectives: This study aimed to investigate the protective effects of hydrogen-rich water (HW) intake on renal injury in neonatal rats with high oxygen loading. Materials: We used pregnant and newborn Sprague-Dawley rats. Methods: Four groups were set up, with mother and newborn rats immediately after delivery as one group: RA-PW (room air and purified water), RA-HW (room air and HW), O2-PW (80% oxygen and purified water), and O2-HW (80% oxygen and HW). The newborn rats were maintained in either a normoxic (room air, 21% oxygen) or controlled hyperoxic (80% oxygen) environment from birth. Then, HW (O2-HW and RA-HW groups) or PW (O2-PW and RA-PW groups) was administered to parents of each group. Results: The number of immature glomeruli significantly increased in the O2-PW group (exposed to hyperoxia). Conversely, the O2-HW group had significantly fewer immature glomeruli than O2-PW group. In the RT-PCR analysis of kidney tissue, α-SMA, TGF-ß, and TNF-α levels were significantly higher in the O2-PW group than in the RA-PW group and significantly lower in the O2-HW group than in the O2-PW group. Conclusions: HW intake can potentially reduce oxidative stress and prevent renal injury in neonates with high oxygen loading.