Association between maternal blood or cord blood metal concentrations and catch-up growth in children born small for gestational age: an analysis by the Japan environment and children's study.

BACKGROUND: Catch-up growth issues among children born small for gestational age (SGA) present a substantial public health challenge. Prenatal exposure to heavy metals can cause adverse effects on birth weight. However, comprehensive studies on the accurate assessment of individual blood concentrations of heavy metals and their effect on the failure to achieve catch-up growth remain unavailable. This study aimed to evaluate the effects of uterine exposure to toxic metals cadmium, lead, and mercury and essential trace metals manganese and selenium at low concentrations on the postnatal growth of children born SGA. METHODS: Data on newborn birth size and other factors were obtained from the medical record transcripts and self-administered questionnaires of participants in the Japan Environment and Children's Study. The blood concentrations of lead, cadmium, mercury, selenium, and manganese in pregnant women in their second or third trimester were determined by inductively coupled plasma mass spectrometry. These heavy metal concentrations were also assessed in pregnant women's cord blood. Furthermore, the relationship between each heavy metal and height measure/catch-up growth in SGA children aged 4 years was analyzed using linear and logistic regression methods. These models were adjusted for confounders. RESULTS: We studied 4683 mother-child pairings from 103,060 pregnancies included in the Japan Environment and Children's Study. Of these, 278 pairs were also analyzed using cord blood. At 3 and 4 years old, 10.7% and 9.0% of children who were born below the 10th percentile of body weight had height standard deviation scores (SDSs) below 2, respectively. Cord blood cadmium concentrations were associated with the inability to catch up in growth by 3 or 4 years old and the height SDS at 3 years old. In maternal blood, only manganese was positively associated with the height SDS of SGA children aged 2 years; however, it was not significantly associated with catch-up growth in these children. CONCLUSION: Cadmium exposure is associated with failed catch-up development in SGA children. These new findings could help identify children highly at risk of failing to catch up in growth, and could motivate the elimination of heavy metal (especially cadmium) pollution to improve SGA children's growth.

Insulin receptor substrate 1, but not IRS2, plays a dominant role in regulating pancreatic alpha cell function in mice.

Dysregulated glucagon secretion deteriorates glycemic control in type 1 and type 2 diabetes. Although insulin is known to regulate glucagon secretion via its cognate receptor (insulin receptor, INSR) in pancreatic alpha cells, the role of downstream proteins and signaling pathways underlying insulin's activities are not fully defined. Using in vivo (knockout) and in vitro (knockdown) studies targeting insulin receptor substrate (IRS) proteins, we compared the relative roles of IRS1 and IRS2 in regulating alpha cell function. Alpha cell-specific IRS1-knockout mice exhibited glucose intolerance and inappropriate glucagon suppression during glucose tolerance tests. In contrast, alpha cell-specific IRS2-knockout animals manifested normal glucose tolerance and suppression of glucagon secretion after glucose administration. Alpha cell lines with stable IRS1 knockdown could not repress glucagon mRNA expression and exhibited a reduction in phosphorylation of AKT Ser/Thr kinase (AKT, at Ser-473 and Thr-308). AlphaIRS1KD cells also displayed suppressed global protein translation, including reduced glucagon expression, impaired cytoplasmic Ca2+ response, and mitochondrial dysfunction. This was supported by the identification of novel IRS1-specific downstream target genes, Trpc3 and Cartpt, that are associated with glucagon regulation in alpha cells. These results provide evidence that IRS1, rather than IRS2, is a dominant regulator of pancreatic alpha cell function.

Activated invariant natural killer T cells directly recognize leukemia cells in a CD1d-independent manner.

Invariant natural killer T (iNKT) cells are innate-like CD1d-restricted T cells that express the invariant T cell receptor (TCR) composed of Vα24 and Vß11 in humans. iNKT cells specifically recognize glycolipid antigens such as α-galactosylceramide (αGalCer) presented by CD1d. iNKT cells show direct cytotoxicity toward CD1d-positive tumor cells, especially when CD1d presents glycolipid antigens. However, iNKT cell recognition of CD1d-negative tumor cells is unknown, and direct cytotoxicity of iNKT cells toward CD1d-negative tumor cells remains controversial. Here, we demonstrate that activated iNKT cells recognize leukemia cells in a CD1d-independent manner, however still in a TCR-mediated way. iNKT cells degranulated and released Th1 cytokines toward CD1d-negative leukemia cells (K562, HL-60, REH) as well as αGalCer-loaded CD1d-positive Jurkat cells. The CD1d-independent cytotoxicity was enhanced by natural killer cell-activating receptors such as NKG2D, 2B4, DNAM-1, LFA-1 and CD2, but iNKT cells did not depend on these receptors for the recognition of CD1d-negative leukemia cells. In contrast, TCR was essential for CD1d-independent recognition and cytotoxicity. iNKT cells degranulated toward patient-derived leukemia cells independently of CD1d expression. iNKT cells targeted myeloid malignancies more than acute lymphoblastic leukemia. These findings reveal a novel anti-tumor mechanism of iNKT cells in targeting CD1d-negative tumor cells and indicate the potential of iNKT cells for clinical application to treat leukemia independently of CD1d.

MicroRNAs profiling in fibroblasts derived from patients with Gorlin syndrome.

Gorlin syndrome (GS) is a hereditary disorder with tumorigenicity, caused by constitutive hyperactivity of hedgehog signaling. Smoothened (SMO) antagonists have been effectively used in the clinical treatment of hedgehog signaling-related cancer. However, these treatments have led to problematic side effects, including severe adverse reactions and drug resistance from additional somatic mutations. We profiled microRNAs in GS fibroblasts to explore a novel therapeutic target for controlling hyper-activated hedgehog signaling. To identify GS-related microRNAs, we analyzed dermal fibroblasts from five patients with GS and three normal controls. We used microarray comparative genomic hybridization to screen 632 human microRNAs in GS fibroblasts. We identified 16 down- and 19 upregulated microRNAs with over twofold change in expression. We validated the increased expression of four microRNAs, confirming hsa-miR-196a-5p downregulation and hsa-miR-4485 upregulation using real-time PCR. Moreover, hsa-miR-196a-5p is complementary to sites in the 3' UTR of MAP3K1, which exhibits upregulated expression at mRNA and protein levels in GS fibroblasts. In addition, hedgehog signal induction with exogenous components decreased miR-196a-5p expression and increased map3k1 expression in a mouse mesenchymal cell line. Given that MAP3K1 has been reported to activate hedgehog signaling, hsa-miR-196a-5p may contribute to the positive feedback loop in this pathway.

Psoitis and multiple venous thromboses caused by Panton Valentine Leukocidin-positive methicillin-sensitive Staphylococcus aureus in a 12-year-old girl: A case report.

Panton Valentine Leukocidin (PVL) is one of the many toxins produced by Staphylococcus aureus. In Japan, PVL-positive S. aureus strains are mainly methicillin-resistant S. aureus (MRSA). Data regarding PVL-positive methicillin-sensitive S. aureus (MSSA) are scarce. In this report, we describe a case of severe infection by PVL-positive MSSA. A 12-year-old healthy girl was admitted with high fever and pain in the lower back. Computed tomography revealed a diagnosis of psoitis and multiple venous thromboses. Blood cultures obtained after admission revealed infection with MSSA. Her fever continued despite adequate antibiotic therapy. On the fifth hospitalization day, she developed bladder dysfunction, and an abscess was noted near the third lumbar vertebra. She underwent an emergency operation and recovered. Bacterial analyses revealed that the causative MSSA was a PVL-producing single variant of ST8 (related to USA300clone), of sequence type 2149. PVL is known to cause platelet activation. This case demonstrates the need for detailed analyses of the causative strain of bacteria in cases of S. aureus infection with deep vein thrombosis, even in cases of known MSSA infection.

Ellis-van Creveld syndrome associated with chronic intestinal pseudo-obstruction.

Ellis-van Creveld (EVC) syndrome is a rare autosomal recessive disorder characterized by hypoplastic nails, polydactyly, and achondroplasia. Patients usually exhibit normal cognitive function and no remarkable developmental delay. We herein present an unusual case of EVC syndrome. A Japanese 2-year-old boy was born at term, but immediately developed severe respiratory failure due to thorax deformity, postaxial polydactyly and nail hypoplasia. We identified a novel pattern of germinal compound heterozygous nonsense EVC2 mutations of c.1814C > A (p. S605X) and c.2653C > T (p. R885X), leading to the diagnosis of EVC syndrome. Interestingly, he also had severe developmental delay, and suddenly developed excessive abdominal distension at the age of 2. On surgery, extensive necrotic bowel with chronic intestinal pseudo-obstruction was noted. This is, to our knowledge, a most severe phenotype of EVC syndrome, illustrating that the specific pattern of EVC2 compound heterozygous mutations may cause severe developmental delay and intestinal malfunction.

A case report of a child with pulmonary hypertension associated with SARS-CoV-2 infection.

We encountered a pediatric case of pulmonary hypertension triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. A 14-year-old girl was brought to the emergency department of our hospital with fever, respiratory distress, and impaired consciousness. She tested positive for SARS-CoV-2 upon a polymerase chain reaction examination and had prolonged hypoxemia without pneumonia. An echocardiography revealed elevated right ventricular pressure. She was diagnosed with pilocytic astrocytoma at the age of 10 years and underwent a resection of a pituitary tumor. Hormone replacement therapy was administered postoperatively, but her growth hormones were not activated because of concerns about tumor recurrence. Echocardiography at the age of 13 years showed normal right ventricular pressure. On admission, she had an abnormal liver function, elevated liver fibrosis markers, a decreased platelet count, and hepatosplenomegaly, suggesting pulmonary and portal hypertension. The diagnosis was pulmonary hypertension associated with SARS-CoV-2 infection. The mechanism of the pulmonary hypertension was thought to be portal hypertension owing to growth hormone deficiency and SARS-CoV-2 infection. The patient's symptoms improved with oxygenation and bed rest without additional targeted pulmonary hypertension therapy, and her right ventricular pressure decreased. This case demonstrates that a pediatric patient with subclinical pulmonary hypertension may develop pulmonary hypertension triggered by SARS-CoV-2 infection.

AP2 adaptor complex mediates bile salt export pump internalization and modulates its hepatocanalicular expression and transport function.

UNLABELLED: The bile salt export pump (BSEP) mediates the biliary excretion of bile salts and its dysfunction induces intrahepatic cholestasis. Reduced canalicular expression of BSEP resulting from the promotion of its internalization is one of the causes of this disease state. However, the molecular mechanism underlying BSEP internalization from the canalicular membrane (CM) remains unknown. We have shown previously that 4-phenylbutyrate (4PBA), a drug used for ornithine transcarbamylase deficiency (OTCD), inhibited internalization and subsequent degradation of cell-surface-resident BSEP. The current study found that 4PBA treatment decreased significantly the expression of α- and µ2-adaptin, both of which are subunits of the AP2 adaptor complex (AP2) that mediates clathrin-dependent endocytosis, in liver specimens from rats and patients with OTCD, and that BSEP has potential AP2 recognition motifs in its cytosolic region. Based on this, the role of AP2 in BSEP internalization was explored further. In vitro analysis with 3×FLAG-human BSEP-expressing HeLa cells and human sandwich-culture hepatocytes indicates that the impairment of AP2 function by RNA interference targeting of α-adaptin inhibits BSEP internalization from the plasma membrane and increases its cell-surface expression and transport function. Studies using immunostaining, coimmunoprecipitation, glutathione S-transferase pulldown assay, and time-lapse imaging show that AP2 interacts with BSEP at the CM through a tyrosine motif at the carboxyl terminus of BSEP and mediates BSEP internalization from the CM of hepatocytes. CONCLUSION: AP2 mediates the internalization and subsequent degradation of CM-resident BSEP through direct interaction with BSEP and thereby modulates the canalicular expression and transport function of BSEP. This information should be useful for understanding the pathogenesis of severe liver diseases associated with intrahepatic cholestasis.

Sustained high plasma mannose less sensitive to fluctuating blood glucose in glycogen storage disease type Ia children.

Plasma mannose is suggested to be largely generated from liver glycogen-oriented glucose-6-phosphate. This study examined plasma mannose in glycogen storage disease type Ia (GSD Ia) lacking conversion of glucose-6-phosphate to glucose in the liver. We initially examined fasting--and postprandial 2 h--plasma mannose and other blood carbohydrates and lipids for seven GSD Ia children receiving dietary interventions using cornstarch and six healthy age-matched children. Next, one-day successive intra-individual parameter changes were examined for six affected and two control children. Although there were no significant differences in fasting--and postprandial 2 h--glucose and insulin levels, the mannose level of the affected group was invariably much higher than that of the control group (p < 0.001): the fasting level of the affected group was about two-fold that of the control group; the postprandial-2 h level remained almost unchanged in the affected group, although it was one-half of the fasting level in the control group. Inter-individual analyses revealed that the GSD Ia group mannose level was significantly and positively correlated with lactate and triglycerides levels at both time points (p < 0.01). In each control, mannose levels fluctuated greatly, maintaining strong and significant negative correlations with glucose and insulin levels (p < 0.001). Correlations were lower or nonexistent in GSD Ia children. In individuals with high lactate and triglycerides levels, strikingly high mannose levels never changed against glucose and insulin fluctuations. Plasma mannose is less sensitive to blood glucose and insulin in GSD Ia children. Its basal level and the fluctuation pattern differ by their metabolic activity.

Brain structure alterations in girls with central precocious puberty.

Purpose: Central precocious puberty (CPP) is puberty that occurs at an unusually early age with several negative psychological outcomes. There is a paucity of data on the morphological characteristics of the brain in CPP. This study aimed to determine the structural differences in the brain of patients with CPP. Methods: We performed voxel- and surface-based morphometric analyses of 1.5 T T1-weighted brain images scanned from 15 girls with CPP and 13 age-matched non-CPP controls (NC). All patients with CPP were diagnosed by gonadotropin-releasing hormone (GnRH) stimulation test. The magnetic resonance imaging (MRI) data were evaluated using Levene's test for equality of variances and a two-tailed unpaired t-test for equality of means. False discovery rate correction for multiple comparisons was applied using the Benjamini-Hochberg procedure. Results: Morphometric analyses of the brain scans identified 33 candidate measurements. Subsequently, increased thickness of the right precuneus was identified in the patients with CPP using general linear models and visualizations of cortical thickness with a t-statistical map and a random field theory map. Conclusion: The brain scans of the patients with CPP showed specific morphological differences to those of the control. The features of brain morphology in CPP identified in this study could contribute to further understanding the association between CPP and detrimental psychological outcomes.

A Brain Morphometry Study with Across-Site Harmonization Using a ComBat-Generalized Additive Model in Children and Adolescents.

Regional anatomical structures of the brain are intimately connected to functions corresponding to specific regions and the temporospatial pattern of genetic expression and their functions from the fetal period to old age. Therefore, quantitative brain morphometry has often been employed in neuroscience investigations, while controlling for the scanner effect of the scanner is a critical issue for ensuring accuracy in brain morphometric studies of rare orphan diseases due to the lack of normal reference values available for multicenter studies. This study aimed to provide across-site normal reference values of global and regional brain volumes for each sex and age group in children and adolescents. We collected magnetic resonance imaging (MRI) examinations of 846 neurotypical participants aged 6.0-17.9 years (339 male and 507 female participants) from 5 institutions comprising healthy volunteers or neurotypical patients without neurological disorders, neuropsychological disorders, or epilepsy. Regional-based analysis using the CIVET 2.1.0. pipeline provided regional brain volumes, and the measurements were across-site combined using ComBat-GAM harmonization. The normal reference values of global and regional brain volumes and lateral indices in our study could be helpful for evaluating the characteristics of the brain morphology of each individual in a clinical setting and investigating the brain morphology of ultra-rare diseases.

Senescence-associated inflammation and inhibition of adipogenesis in subcutaneous fat in Werner syndrome.

Werner syndrome (WS) is a hereditary premature aging disorder characterized by visceral fat accumulation and subcutaneous lipoatrophy, resulting in severe insulin resistance. However, its underlying mechanism remains unclear. In this study, we show that senescence-associated inflammation and suppressed adipogenesis play a role in subcutaneous adipose tissue reduction and dysfunction in WS. Clinical data from four Japanese patients with WS revealed significant associations between the decrease of areas of subcutaneous fat and increased insulin resistance measured by the glucose clamp. Adipose-derived stem cells from the stromal vascular fraction derived from WS subcutaneous adipose tissues (WSVF) showed early replicative senescence and a significant increase in the expression of senescence-associated secretory phenotype (SASP) markers. Additionally, adipogenesis and insulin signaling were suppressed in WSVF, and the expression of adipogenesis suppressor genes and SASP-related genes was increased. Rapamycin, an inhibitor of the mammalian target of rapamycin (mTOR), alleviated premature cellular senescence, rescued the decrease in insulin signaling, and extended the lifespan of WS model of C. elegans. To the best of our knowledge, this study is the first to reveal the critical role of cellular senescence in subcutaneous lipoatrophy and severe insulin resistance in WS, highlighting the therapeutic potential of rapamycin for this disease.

Giant multilocular sex cord tumor with annular tubules associated with precocious puberty.

We report a case of sex cord tumor with annular tubules featuring a giant multilocular cyst, grossly similar to cystadenoma, in the ovary of an 8.5 year old girl. Estrogen-related symptoms, including precocious puberty and irregular uterine bleeding, immediately improved after tumor resection.

Vitamin D Metabolite Ratio in Pregnant Women with Low Blood Vitamin D Concentrations Is Associated with Neonatal Anthropometric Data.

Existing evidence on the correlation between maternal vitamin D concentrations and birth outcomes is conflicting. Investigation of these associations requires accurate assessment of vitamin D status, especially in individuals with low 25-hydroxyvitamin D (25(OH)D) concentrations. This study examined the correlations between birth outcomes and the maternal vitamin D metabolite ratio (VMR) 1 (defined as the ratio of 24,25(OH)2D3 to 25(OH)D) and VMR2 (defined as the ratio of 3-epi-25(OH)D3 to 25(OH)D) using data from the Japan Environment and Children's Study at Chiba Regional Center. A total of 297 mother-neonate pairs were analyzed. Using liquid chromatography-tandem mass spectrometry, we measured 25(OH)D2, 25(OH)D3, 24,25(OH)2D3, and 3-epi-25(OH)D3 concentrations in maternal serum samples. These data were analyzed in relation to birth anthropometric data using multivariable linear regression. Of the study participants, 85.2% showed insufficient vitamin D concentrations. VMR1 was strongly correlated with 25(OH)D concentrations, whereas VMR2 showed a weak correlation. Only VMR2 was associated with all anthropometric data. VMR2 in pregnant women with low vitamin D blood concentrations is a useful marker for neonatal anthropometric data and is independent of 25(OH)D. Accurate measurement of vitamin D metabolites could help better understand the effects of vitamin D on birth outcomes.

Individual and mixed metal maternal blood concentrations in relation to birth size: An analysis of the Japan Environment and Children's Study (JECS).

BACKGROUND: Growth restriction in the prenatal period is a significant public health concern. Metals can negatively affect birth size, and pregnant women may be exposed to metal mixtures. Comprehensive studies analyzing the effects of combined metal exposure with accurate individual blood metal concentrations are limited. The current study investigated the associations between maternal metal exposure and birth size in a large, nationwide Japanese cohort using individual and mixed model approaches. METHODS: Lead, cadmium, mercury, selenium, and manganese blood concentrations were measured in pregnant women in the Japan Environment and Children's Study (JECS). Measurements of infant birth size-including body weight, body length, and head and chest circumference-were collected. Linear and logistic regressions were used for birth size measurements and the odds of an infant being small in size for gestational age, respectively. Associations between combined metal mixtures and measurements at birth were evaluated using quantile g-computation and Bayesian kernel machine regression (BKMR). RESULTS: Of the 103,060 JECS pregnancies, 93,739 mother-infant pairs were analyzed. The linear regression models showed that lead, selenium, cadmium, and manganese-but not mercury-were associated with body weight. Cadmium was associated with length and chest circumference and mercury was associated with head circumference. Quantile g-computation revealed that manganese increased infant birth weight, length, head circumference, and chest circumference. Lead was the strongest negative factor for infant birth weight, length, head circumference, and chest circumference. The BKMR analysis revealed that the metals had an additive, rather than a synergistic effect. CONCLUSION: Metal exposure is associated with infant birth size, with lead and manganese playing a more significant role in Japan. The effects of prenatal combined metal exposure at low levels warrant public health attention.

Investigation of umbilical cord serum miRNAs associated with childhood obesity: A pilot study from a birth cohort study.

We investigated umbilical cord serum microRNA (miRNA) profiles to identify biomarkers of a risk for obesity later in life. Participating children were divided into high- and low-risk groups of obesity based on the timing of adiposity rebound and the body mass index (BMI) at 5 years and randomly selected from each group for this study. 3D-Gene® Human miRNA Oligo Chip was performed using cord serum in five children of both groups. The most relevant miRNAs were confirmed in 33 children of the groups using the TaqMan® microRNA assay. We detected five cord serum miRNAs differentially expressed in children at high risk of obesity compared with the levels in children at low risk, namely, miR-516-3p and miR-130a-3p with increased levels and miR-1260b, miR-4709-3p, and miR194-3p with decreased levels. This study provides the first identification of altered umbilical cord serum miRNAs in childhood obesity.

Cross-sectional study of bone metabolism with nutrition in adult classical phenylketonuric patients diagnosed by neonatal screening.

The mechanism underlying the development of osteopenia or osteoporosis in longstanding phenylketonuria (PKU) remains to be clarified. We investigated the details of bone metabolism in 21 female and 13 male classical PKU patients aged 20-35 years. Vitamin D (VD), parathyroid hormone (PTH), bone turnover markers, and daily nutrient intake were examined. The patients had lower daily energy and protein intake than did the age-matched controls (22 women, 14 men), but their respective fat, VD, and calcium intake did not differ. Serum 1,25-dihydroxy VD and 25-hydroxy VD levels in female and male patient groups were significantly higher and lower than those in respective control groups (females, P < 0.001; males, P < 0.05 and P < 0.01, respectively). Serum intact PTH levels were significantly higher in the female patient group (P < 0.05). Urinary calcium levels in the patient groups were significantly higher than those of the control subjects (females, P < 0.001; males, P < 0.05). Bone resorption markers were significantly higher in patients than in controls, although bone formation markers were not different. Patient serum levels of osteoprotegerin-inhibiting bone resorption were significantly lower (females, P < 0.001; males, P < 0.01). None of the bone parameters correlated significantly with serum phenylalanine or nutrient intake. PKU patients exhibited lower VD status and more rapid bone resorption despite normal calcium-VD intakes.

Establishment of diagnosis by bisulfite-treated methylation-specific PCR method and analysis of clinical characteristics of pseudohypoparathyroidism type 1b.

Pathogenesis of pseudohypoparathyroidism type 1b (PHP-1b) is related to the loss of methylation at the GNAS exon A/B region, which is combined with epigenetic defects at other differentially methylated GNAS regions in most sporadic cases. In this study, we established a method for evaluating the methylation status of a CpG island in exon A/B using a methylation-specific polymerase chain reaction (MSPCR). We designed two primer pairs specific for the methylated and unmethylated alleles and evaluated the methylation status of GNAS exon A/B in samples from PHP-1b patients and normal controls. We examined 20 Japanese patients and 20 normal controls, and one primer set was found to be appropriate for diagnosis. Furthermore, we evaluated the clinical data of patients. Weight and height of patients were not significantly different from the normal population. Short stature (adult height ≤ 2SD) was observed in one patient and short metacarpals in two. Obesity was observed in six patients, and no patient showed ectopic subcutaneous calcification. Seven patients showed subclinical hypothyroidism because of resistance to thyroid stimulating hormone, but no patient had an abnormally low free thyroxine level, and none received oral thyroid hormone replacement. For diagnosis of PHP-1b, only clinical data is not sufficient because a few PHP-1b patients show clinical features similar to PHP-1a, and hence, molecular biology techniques are required for correct diagnosis. We concluded that MSPCR is applicable for rapid molecular diagnosis of PHP-1b.

Favorable effect of 4-phenylacetate on liver functions attributable to enhanced bile salt export pump expression in ornithine transcarbamylase-deficient children.

4-Phenylbutyrate (4-PB) acting against hyperammonemia has been administered to patients with urea cycle defects. Results of our recent experiments using animals and cultured cells strongly suggest that this agent enhances the function of bile salt export pump/ATP binding cassette B11 (BSEP/ABCB11) promoting bile acid excretion from hepatocytes to bile canaliculi, although it has not been confirmed in humans. Considering that 4-PB is converted easily into 4-phenylacetate (4-PA) in the liver, such an effect of 4-PB might occur through 4-PA. We performed retrospective analyzes of the effects of 4-PA on the liver functions of three ornithine transcarbamylase (OTC)-deficient female children receiving 4-PA. Two of the three received intravenous administration of 4-PA only at episodic periods of hyperammonemia; the remaining one received it orally at intercurrent periods. Soon after 4-PA administration, the serum total bile acid level was decreased to one-half or one-third of pre-treatment levels, but it returned to the basal levels within one month after 4-PA discontinuation. Other serum parameters for cholestasis such as gamma-glutamyl transferase also decreased markedly. Concomitantly, alanine aminotransferase and aspartate amino transferase levels decreased significantly. Western blot analyzes of the liver samples revealed that the 4-PA administration enhanced BSEP/ABCB11 protein expressions in the membranous fraction of liver cells, although the liver BSEP/ABCB11 messenger RNA level remained unchanged. These results suggest that 4-PA enhanced liver BSEP/ABCB11 function and thereby improved liver functions in OTC-deficient children. For treatment of liver disorders requiring enhancement of BSEP function, 4-PA might be a candidate.