Regulation of Npt2b gene promoter activity by RAR/RXR-C/EBP

Inorganic phosphate (Pi) homeostasis is regulated by intestinal absorption via type II sodium-dependent co-transporter (Npt2b) and by renal reabsorption via Npt2a and Npt2c. Although we previously reported that vitamin A-deficient (VAD) rats had increased urine Pi excretion through the decreased renal expression of Npt2a and Npt2c, the effect of vitamin A on the intestinal Npt2b expression remains unclear. In this study, we investigated the effects of treatment with all-trans retinoic acid (ATRA), a metabolite of vitamin A, on the Pi absorption and the Npt2b expression in the intestine of VAD rats, as well as and the underlying molecular mechanisms. In VAD rats, the intestinal Pi uptake activity and the expression of Npt2b were increased, but were reduced by the administration of ATRA. The transcriptional activity of reporter plasmid containing the promoter region of the rat Npt2b gene was reduced by ATRA in NIH3T3 cells overexpressing retinoic acid receptor (RAR) and retinoid X receptor (RXR). On the other hand, CCAAT/enhancer-binding proteins (C/EBP) induced transcriptional activity of the Npt2b gene. Knockdown of the C/EBP gene and a mutation analysis of the C/EBP responsible element in the Npt2b gene promoter indicated that C/EBP plays a pivotal role in the regulation of Npt2b gene transcriptional activity by ATRA. EMSA revealed that the RAR/RXR complex inhibits binding of C/EBP to Npt2 b gene promoter. Together, these results suggest that ATRA may reduce the intestinal Pi uptake by preventing C/EBP activation of the intestinal Npt2b gene

Use of the index of pulmonary vascular disease for predicting long-term outcome of pulmonary arterial hypertension associated with congenital heart disease

AimsLimited data exist on risk factors for the long-term outcome of pulmonary arterial hypertension (PAH) associated with congenital heart disease (CHD-PAH). We focused on the index of pulmonary vascular disease (IPVD), an assessment system for pulmonary artery pathology specimens. The IPVD classifies pulmonary vascular lesions into four categories based on severity: (1) no intimal thickening, (2) cellular thickening of the intima, (3) fibrous thickening of the intima, and (4) destruction of the tunica media, with the overall grade expressed as an additive mean of these scores. This study aimed to investigate the relationship between IPVD and the long-term outcome of CHD-PAH.MethodsThis retrospective study examined lung pathology images of 764 patients with CHD-PAH aged <20 years whose lung specimens were submitted to the Japanese Research Institute of Pulmonary Vasculature for pulmonary pathological review between 2001 and 2020. Clinical information was collected retrospectively by each attending physician. The primary endpoint was cardiovascular death.ResultsThe 5-year, 10-year, 15-year, and 20-year cardiovascular death-free survival rates for all patients were 92.0%, 90.4%, 87.3%, and 86.1%, respectively. The group with an IPVD of ≥2.0 had significantly poorer survival than the group with an IPVD <2.0 (P = .037). The Cox proportional hazards model adjusted for the presence of congenital anomaly syndromes associated with pulmonary hypertension, and age at lung biopsy showed similar results (hazard ratio 4.46; 95% confidence interval: 1.45–13.73; P = .009).ConclusionsThe IPVD scoring system is useful for predicting the long-term outcome of CHD-PAH. For patients with an IPVD of ≥2.0, treatment strategies, including choosing palliative procedures such as pulmonary artery banding to restrict pulmonary blood flow and postponement of intracardiac repair, should be more carefully considered

The cardiac blood supply-workload balance in children

It is well known that the reflected pressure wave in small children returns earlier than that in adolescent. The reason of early return of the reflected pressure wave in infancy is their height. The short distance between heart and reflection point makes the reflected pressure wave returning to the heart earlier. In adult, the early return (during systole) of the reflected pressure wave means disadvantage to cardiac blood supply-workload balance. The purpose of this study was to clarify whether the early return of the reflected pressure wave in small children impairs the cardiac blood supply-workload balance. This study enrolled 37 small left-to-right shunt patients with normal aortic circulation below 15 years of age. The aortic pressure waveform was recorded using a pressure sensor mounted catheter, and augmentation index and subendocardial viability ratio were calculated. The age of patients was 6.1 ± 3.2 years. The augmentation index was 8.7 ± 14.3 % and the index had a negative correlation with patients' age (r = -0.6243, p < 0.0001). The subendocardial viability ratio, which means the cardiac blood supply-workload balance, was 0.92 ± 0.14 and the index had a positive relationship with patients' age (r = 0.6435, p < 0.0001). The cardiac blood supply-workload balance gradually improves from infancy to young adulthood. One of the causes of the unfavorable cardiac blood supply-workload balance in infancy would be the accelerated aortic pressure wave reflection due to their short height

Decreased baseline variability on fetal heart rate pattern in a fetus with heterotaxy syndrome

In a fetus with suspected heterotaxy syndrome, a decreased/absent baseline variability of fetal heart rate pattern developed at gestational week 36(+5) and continued for 5 days until birth at gestational week 37(+2), while repeat biophysical profile scorings with ultrasound were consistently unremarkable. This neonate weighing 2404 g with Apgar scores of 7 (1-min) and 8 (5-min) and umbilical arterial cord blood pH of 7.28 with base deficit of 3.9mmol/L, showed a heart rate of 120 b.p.m. for 3 h after birth, but subsequently developed sinus bradycardia (84 b.p.m.) unresponsive to crying. Isoproterenol initiated 9 h after birth was effective in the increase of heart rate to 120 b.p.m. in this neonate. Brain magnetic resonance imaging at 16 days of age was unremarkable. The decreased/absent baseline variability of fetal heart rate pattern was speculated to have been caused by sinus node dysfunction, and not by reduced fetal oxygenation in this case

Malformed newborns in a tertiary center

Aim: This retrospective study was performed to determine the frequency of malformed infants born at a tertiary center in Hokkaido, Japan. The accuracy of prenatal diagnosis rates was also investigated. Methods: An observational study was performed using data of 1509 and 1743 newborn infants at a single center during two study periods, 2005-2009 (first) and 2010-2014 (second), respectively. Cases including minor anomalies (accessory auricle, nevus and fistula auris congenita) were not included. Results: In total, 274 and 569 malformations were identified in 191 and 337 newborn infants in the first and second study periods, respectively. The number of malformed infants increased significantly over time (13% [191/1509] vs 19% [337/1743], respectively; P < 0.001), mainly as a result of an increase in cases of congenital heart disease (CHD), from 59 to 141 (31% [59/191] vs 42% [141/337] of all malformed infants in the first and second periods, respectively). The overall accurate prenatal diagnosis rate improved over time from 47% (128/274) to 58% (329/569) because of significant improvements in accurate prenatal diagnosis of CHD subtypes (23% [16/70] vs 65% [151/232] in the first and second periods, respectively, P < 0.0001). Conclusions: The frequency of malformed newborns was higher in the tertiary center than in the general population. The increased number of cases with prenatal suspicion and diagnosis of CHD contributed to the increased frequency of malformed infants during the study period