Kazumichi Fujioka

Does thrombocytopenia contribute to patent ductus arteriosus

nature medicine volume 17 | number 1 | january 2011 29 addition, they showed in a retrospective clinical study that thrombocytopenia increases the risk for PDA in German premature newborns2. To test whether thrombocytopenia generally increases the risk for PDA, we investigated the association between PDA and thrombocytopenia in Japanese premature newborns with a retrospective study at Kobe University Hospital in Japan using the same experimental design as described by Echtler et al.2. We diagnosed DA closure as the absence the definition of osteoarthritis is a major limitation for human genetic studies of osteoarthritis research worldwide, as the KL grading system is limited in its reproducibility and sensitivity as a result of the subjective judgment of individual observers and the categorical classification into only five grade scales. More importantly, in human genetic studies on common diseases such as osteoarthritis with a high prevalence, selection of appropriate and disease-free controls is essential to avoid potential bias resulting from contamination of the control group with affected subjects. The Nakajima et al.6 control group may not be an appropriately disease-free group, again resulting in a decrease of the detection power. According to their references9–15, subjects that are diagnosed to be free of disease by radiographs (KL = 0 or 1) are apparently limited to small cohorts and are very low in number, so that the majority are those without radiographic diagnosis, including the ‘healthy’ population and the subjects with other diseases or trauma. The abovementioned ROAD epidemiologic study has shown a high prevalence of knee osteoarthritis in the Japanese population (KL ≥ 2, 61.9%; KL ≥ 3, 20.6%)8. Furthermore, the ROAD study has also revealed that the prevalence of pain-free subjects is 67.2% and that prevalence of people with KL grades 0 or 1 is 38.1%, indicating that a considerable number of asymptomatic individuals with osteoarthritis are included in the so-called healthy population. Hence, a substantial percentage of the control group used by Nakajima et al.6 may actually be undiagnosed cases. Because the MAF of their case group (KL = 2, 3 or 4; 12.8%) is lower than that of our control group (KL = 0 or 1; 15.2%), supporting an inverse correlation between MAF and KL scores, the discrepancy between our results and theirs may largely result from the inclusion criteria of their control group. Owing to the abovementioned limitations of conventional genetic approaches, the study by Nakajima et al.6 results in very small statistical powers of detecting susceptibility in all populations: 0.13, 0.29, 0.16 and 0.03 for Japanese, Chinese, European and Australian populations, respectively, calculated on the basis of their respective allele frequencies, as compared with the statistical power of 0.71 in our study2. Their statement that “the power of the association study is >80% for our Japanese cohort alone,” may be scientifically inaccurate, as this number may be calculated on the basis of our allele frequency using case and control groups with more stringent selection criteria than were used in their study, as mentioned above. The minimum number of subjects required for the statistical power of >0.8, as they claim, should be 11.7, 4.2, 8.4 and ~3 × 106 times larger for their Japanese, Chinese, European and Australian populations, respectively. This is also owing to very low MAFs in European and Australian populations. Hence, an association analysis of the rs17039192 SNP in their populations, as well as including them in the meta-analysis, is not easily achieved, although studies on different SNPs of the EPAS1 gene with higher MAFs, if any should exist in these populations, might be of interest. Overall, we disagree with the assertions by Nakajima et al.6, as their study possibly compares a case group with ambiguous definition to a control group that may contain affected subjects. Furthermore, although the P value for rs17039192 and its association with osteoarthritis in our study2 is not very striking, our luciferase assay nonetheless shows that a single rs17039192 mutation causes a significant change of the EPAS1 promoter activity in cultured human chondrocytes2, supporting that this is a strong functional SNP.

Hypoalbuminemia following Abdominal Surgery Leads to High Serum Unbound Bilirubin Concentrations in Newborns Soon after Birth

Background: The serum concentration of unbound bilirubin (UB), which is bilirubin not bound to albumin (Alb), is a better index than total bilirubin concentration (TB) for identifying infants at risk for developing bilirubin neurotoxicity. The degree to which the hypoalbuminemia following abdominal surgery in jaundiced newborns affects bilirubin binding is unknown. Objective: To determine whether lower Alb occurring in newborns undergoing abdominal surgery shortly after birth results in significantly higher UB in serum versus nonsurgical patients at comparable serum TB. Methods: A matched case-control study was conducted with term and late-preterm newborns. The surgery group included 15 newborns who underwent abdominal operation within 3 days after birth. Clinical and laboratory data (serum UB, TB, and Alb concentrations, UB/TB ratio, and binding constant) in the surgery group were collected and compared with those of 30 control newborns who did not undergo abdominal surgery (control group). Results: Serum UB and the UB/TB ratio in the surgery group were significantly higher than those in the control group (p < 0.02, p < 0.001, respectively), whereas there were no significant differences in serum TB and binding constant between the groups. Serum Alb concentrations in the surgery group were significantly lower than those in the control group (p < 0.001). When pre- and postoperative serum Alb concentrations were compared, there was a significant decrease from 3.4 to 2.7 g/dl (p < 0.001). Conclusions: Our study suggests that hypoalbuminemia following abdominal surgery causes a higher serum UB at comparable serum TB in newborns.

Association of a vascular endothelial growth factor polymorphism with the development of bronchopulmonary dysplasia in Japanese premature newborns

Our objective was to correlate vascular endothelial growth factor (VEGF) genetic polymorphisms with the risk of bronchopulmonary dysplasia (BPD) development in premature newborns. Fifty-five newborns with BPD (BPD: median gestational age [GA]: 27 weeks, birthweight [BW]: 786 g) and 42 newborns without BPD (non-BPD: median GA: 29 weeks, BW: 1,165 g), who were born at <32 weeks gestational age and were admitted to Kobe University Hospital, were included. BPD was defined as oxygen dependency at 36 weeks postmenstrual age. Genomic DNA was extracted from the umbilical cord, cord blood, or buccal mucosa. Six VEGF genotypes (-1498T > C, -1154G > A, -634C > G, -7C > T, 936C > T, and 1612G > A) were determined by DNA sequencing. Clinical characteristics, and allele and genotype frequencies of VEGF in the BPD and non-BPD groups were analyzed. G allele frequencies in -634C > G of the BPD group were significantly higher than in the non-BPD group (66.4% vs. 50%, P = 0.02). -634C > G genotype distributions differed significantly between the BPD and non-BPD groups (BPD: CC 7%/CG 53%/GG 40%; non-BPD: CC 24%/CG 52%/GG 24%; P = 0.04). Multivariate logistic regression showed that duration of ventilation, VEGF-634G > C G alleles, and male gender were independent risk factors for BPD. In conclusion, polymorphism VEGF -634C > G may influence the risk of BPD.

Is bilirubin/albumin ratio correlated with unbound bilirubin concentration?

Background:  The American Academy of Pediatrics guidelines recommend that the total bilirubin (TB)/albumin (Alb) ratio (B/A ratio), instead of serum concentration of unbound bilirubin (UB), can be used with TB for determining treatment modality for jaundiced newborns ≥35 weeks of gestation. It is unknown, however, whether the B/A ratio is actually correlated with serum UB.

Novel treatment strategy for Japanese newborns with high serum unbound bilirubin

Serum unbound bilirubin (UB) is a measure of bilirubin not bound to albumin, and has been reported to be better than total bilirubin level at identifying infants at risk of developing bilirubin‐induced neurotoxicity, including auditory abnormalities. A detailed treatment strategy for newborns with high serum UB has not been established. The aim of this study was to assess auditory outcomes in newborns with serum UB ≥1.00 μg/dL who were treated according to a novel treatment protocol.

Induction of Heme OXYGENASE-1 Attenuates the Severity of Sepsis in A Non-Surgical Preterm Mouse Model.

ABSTRACT Preterm sepsis is characterized by systemic bacterial invasion and inflammatory response. Its pathogenesis is unclear due to lack of proper animal models. Heme oxygenase-1 (HO-1) can affect physiologic and pathologic conditions through its anti-inflammatory, antioxidative, and anti-apoptotic properties. Since HO-1 is developmentally regulated, it may play a role in the pathogenesis of preterm sepsis. For this study, sepsis was induced using the non-surgical “cecal slurry” (CS) model. CS was given intraperitoneally at various doses to 4-day-old newborn mice to determine dose-dependent effects. The LD40 was then given and changes in bodyweight, bacterial colonization of organs, hematology, serum biochemistry, and immunomodulatory gene expression were determined. We found a dose-dependent mortality with an LD40 of 2.0 mg/g. Significant bacterial colonization and hematological changes (leukocytopenia, thrombocytopenia, and lymphocytopenia) and increased gene expression of pro-inflammatory cytokines, pattern-recognition receptors, and other genes related to immune responses were also observed. Twenty-four hours post-sepsis induction, bodyweight loss was associated with mortality and organ damage. Finally, to elucidate a protective role of HO-1, 30-&mgr;mol heme/kg was given subcutaneously 24 h pre-sepsis induction. HO activity in livers and spleens significantly increased 64% and 50% over age-matched controls 24 h post-heme administration. Importantly, heme significantly reduced mortality from 40.9% to 6.3% (P <0.005) and gene expression of pro-inflammatory cytokines (Ccl5, Cxcl10, IL-1b, and Ifng). We conclude that the CS model can be used as a model to study preterm sepsis. Because induction of HO-1 significantly reduced mortality, we speculate that HO-1 may confer protection against sepsis in preterm infants.

Inhibition of heme oxygenase activity using a microparticle formulation of zinc protoporphyrin in an acute hemolytic newborn mouse model

Background:Increased bilirubin production due to hemolysis can lead to neonatal hyperbilirubinemia. Inhibition of heme oxygenase (HO), the rate-limiting enzyme in heme catabolism, by metalloporphyrins (Mps) may be an ideal preventive strategy for neonatal hemolytic disease. Zinc protoporphyrin (ZnPP) is a naturally occurring Mp, potent, not phototoxic, with minimal HO-1 upregulation, but is not orally absorbed. Recently, we designed a lipid-based ZnPP formulation (ZnPP-Lipid), which is orally absorbed by newborn mice. Here, we evaluated the efficacy of ZnPP-Lipid in heme-loaded newborn mice, a model analogous to hemolytic infants.Methods:After 24 h of heme administration (30 µmol/kg s.c.), 4-d-old mice were given 30 µmol ZnPP-Lipid/kg via intragastric injections. After 3 h, liver and brain HO activity were measured. HO-1 upregulation was assessed by determinations of HO-1 protein, promoter activity, and mRNA by Western blot, in vivo bioluminescence imaging, and RT–PCR, respectively.Results:After heme loading, liver HO activity significantly increased ~1.6-fold, which was inhibited in a dose-dependent manner by ZnPP-Lipid. A dose of 30 µmol/kg returned activity to control levels. Brain HO activity was not inhibited. No significant increases in liver and brain HO-1 protein, promoter activity, and mRNA were observed.Conclusion:ZnPP-Lipid is effective and thus has potential for treating neonatal hyperbilirubinemia due to hemolysis.

Renin is activated in monochorionic diamniotic twins with birthweight discordance who do not have twin-to-twin transfusion syndrome

Objective:To assess renin, aldosterone, human atrial natriuretic peptide (hANP) and brain natriuretic peptide (BNP) levels in cord blood from monochorionic diamniotic (MD) twins with a birthweight (BW) discordance that do not satisfy the criteria of twin-to-twin transfusion syndrome (TTTS).Study Design:Cord blood samples were obtained from 28 MD twins without TTTS. They were divided into two groups on the basis of BW discordance as follows: large (>7.5%) and small (⩽7.5%). Cord blood renin, aldosterone, hANP and BNP levels were measured.Result:Renin levels in MD twins with a large BW discordance were significantly higher than those in MD twins with a small BW discordance, with no significant differences in aldosterone, hANP and BNP levels. A significant correlation was found between renin levels and BW discordance.Conclusion:Renin is activated in MD twins with a BW discordance of >7.5%, even in non-TTTS.

N-terminal pro-brain natriuretic peptide levels in monochorionic diamniotic twins with selective intrauterine growth restriction

Objective:To compare serum N-terminal pro-brain natriuretic peptide levels at birth between monochorionic diamniotic twins with and without selective intrauterine growth restriction.Study Design:Blood samples were collected from 73 monochorionic diamniotic twins without twin-to-twin transfusion syndrome. Two groups were studied on the basis of fetal ultrasonographic findings: 16 twins with and 57 twins without selective intrauterine growth restriction. Selective intrauterine growth restriction was defined as an estimated fetal weight below the 10th percentile in one twin at 18 to 26 weeks of gestation. Serum N-terminal pro-brain natriuretic peptide levels were measured.Result:Serum N-terminal pro-brain natriuretic peptide levels in monochorionic diamniotic twins with selective intrauterine growth restriction were significantly higher than in those without selective intrauterine growth restriction. Selective intrauterine growth restriction was independently associated with increased N-terminal pro-brain natriuretic peptide levels.Conclusion:N-terminal pro-brain natriuretic peptide levels at birth are elevated in monochorionic diamniotic twins with selective intrauterine growth restriction.

The lowest surviving birth weight infant delivered from a systemic lupus erythematosus mother with antiphospholipid syndrome

We report the intact surviving case of a newborn with a birth weight of 412 g delivered from an active systemic lupus erythematosus (SLE) mother with antiphospholipid syndrome. A review of the literature revealed that our infant is the lowest surviving birth weight in newborns from SLE mothers to date.