A Model to Study Antioxidant Regulation of Endotoxemia-Modulated Neonatal Granulopoiesis and Granulocyte Apoptosis

Yang, Kuender D.; Chen, Mei-Zu; Teng, Ru-Jeng; Yang, Mingyu; Liu, Hsiu-Chin; Chen, Rong‐Fu; Hsu, Te‐Yao; Shaio, Men‐Fang

doi:10.1203/00006450-200012000-00021

Cited by 15 publications

(13 citation statements)

References 32 publications

(37 reference statements)

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“…In this study, there was DNA damage in five (11%) of the controls, which may be explained by the fact that some had mild respiratory distress with no evidence of sepsis. Yang et al (27) observed that spontaneous in vitro granulocyte apoptosis at 6 hours, as reflected by phosphatidyl serine expression on the cell surface, was higher in granulocytes from human umbilical cord blood than in those from adult blood, and that DNA fragmentation, which is a late apoptotic marker, occurs by induction of granulocyte apoptosis. Scheel-Toellner et al (28) found that neutrophils die even in the absence of any extrinsic factors, which is known as spontaneous death.…”

Section: Discussionmentioning

confidence: 99%

Apoptotic Changes in the Early Diagnosis and Severity Determination of Neonatal Sepsis

Barseem

Helwa

2016

Iran J Pediatr

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Objectives: The aim of this study was to assess the presence of DNA damage in full-term newborns with neonatal sepsis. Methods: Sixty neonates with early onset neonatal sepsis and 45 apparently healthy controls were enrolled in the study. Screening of neonates was done using a modified clinical sepsis score and hematological scoring system, adjusted to the results of blood culture and screening tests. Complete blood count, C-reactive protein (CRP), and DNA studies were done. Results: Sepsis was likely in 41 (68.3%) patients with scores of 3 or 4 and CRP levels of 12 -48 mg/L. Sepsis was very likely in 19 (31.7%) patients with scores of ≥ 5 and CRP of 48 -96 mg/L. Sepsis was unlikely in all controls with scores of ≤ 2. The mean neutrophil count was 9700 ± 4600/µL in patients and 4230 ± 1400/µL in controls. The higher the total polymorphonuclear count and CRP level, the more severe was the sepsis. Twenty-six of 60 (43.3%) sepsis patients and 5 of 45 controls (11%) had DNA damage. There was a highly significant negative correlation between DNA damage, blood culture results, and CRP levels. Conclusions: DNA damage, demonstrated by clinical and laboratory evidence with a combination of blood cultures, CRP, and hematological scoring system results, can be used as an indicator of both the immune status of the neonate and the severity of the sepsis.

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Section: Discussionmentioning

confidence: 99%

Apoptotic Changes in the Early Diagnosis and Severity Determination of Neonatal Sepsis

Barseem

Helwa

2016

Iran J Pediatr

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“…Our study showed a positive correlation between vitamin D status and ROI production in term infants with maximal effect at a vitamin D status of approximately 65 nmol/l beyond which no added effect was noticed. Yang et al (14) reported that increased ROI production also inhibits granulopoiesis under endotoxin stimulation. Therefore, increased ROI production may combat infection but has a risk of increased tissue damage and decreased granulopoiesis.…”

Section: Discussionmentioning

confidence: 99%

Vitamin D enhances reactive oxygen intermediates production in phagocytic cells in term and preterm infants

et al. 2015

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Background: Newborn infants are endotoxin tolerant which may be responsible for their increased susceptibility to bacterial sepsis. Vitamin D has an immunomodulatory effect and newborn infants are at risk of vitamin D deficiency. We examined the in vitro effect of 1, 25-dihydroxyvitamin D (1,25OHD) on whole blood phagocytic toll-like receptor 4 (TLR4), CD11b, and reactive oxygen intermediates (ROIs) in newborn infants during sepsis. Methods: Whole blood from preterm infants <32-wk gestation, control term neonates, and adults were sampled for phagocytic expression of ROI, TLR4, CD11b in response to lipopolysaccharide (LPS), and 1,25OHD using flow cytometer. results: ROI production from newborn phagocytes incubated with LPS alone was decreased. Pretreatment with 1,25OHD demonstrated increased (P = 0.001) phagocytic ROI production in newborns but not in adults. 1,25OHD did not have any effect on TLR4 and CD11b in both newborns and adults. Pretreatment with ROI inhibitors (apocynin (APO) and diphenyleneiodonium), phosphoinositide 3-kinase (PI3K) inhibitor, and p38 inhibitor blocked neutrophil ROI production. conclusion: Neonatal phagocytic cells had diminished ROI production in the presence of LPS, however, pretreatment with 1,25OHD reversed this hyporesponsiveness. This action by 1,25OHD was mediated by activation of nicotinamide adenine dinucleotide phosphate oxidase system through PI3K signaling enzymes. n eonates can be immune tolerant in the presence of infection, and this state of immune hyporesponsiveness potentially increases neonatal vulnerability to infection (1,2). Endotoxin tolerance is a reduced responsiveness to a bacterial lipopolysaccharide (LPS) challenge following a first encounter with endotoxin. The respiratory burst is an essential mechanism by which neutrophils and monocytes kill invading micro-organisms (3). Antimicrobial activity by newborn neutrophils is decreased (4) due to an altered nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system which is even further decreased in preterm infants (5). Although there is increased superoxide anion (O 2 − ) production in cord blood compared with adults, the generation of hydroxyl radical (.OH) is relatively decreased (6). This defect contrasts to adult neutrophils with increased respiratory burst in response to bacterial pathogens (7).The processes of neutrophil adhesion and diapedesis are mediated by the CD11b subunit adhesion molecule of macrophage-1 antigen (Mac-1) (4). Impairment of neutrophil adherence, chemotaxis, and migration in neonates increases their susceptibility to infection in the first month of life (8). Tolllike receptor 4 (TLR4) plays an important role in detecting microbial infection and triggering antimicrobial host defense responses and endotoxin signaling (9,10). Neonatal neutrophils displayed increased TLR4 expression following heat shock and LPS, in contrast to adults (11). Immunomodulation may protect neonates with sepsis. 1,25-dihydroxyvitamin D (1,25OHD) exerts biological effects in isolated innate immune cells, ...

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“…Granulocytes were recovered from the pellet of the gradient centrifugation by hemolytic depletion of contaminated RBC in 0.83% NH 4 Cl buffer. The purity and viability were Ͼ97%, as we previously described (21). Granulocytes isolated from whole blood with and without TNF␣ for 6 h were subjected to DNA extraction with 0.5% SDS lysing buffer followed by proteinase K digestion (1 mg/mL) of nuclear protein for 4 h at 60°C, as previously described (22).…”

Section: Methodsmentioning

confidence: 99%

“…Granulocytes were isolated from heparinized whole blood by a 4.5% dextran sedimentation of RBC, followed by a density gradient separation by FicollHypaque solution as previously described (21,24). Granulocytes were harvested from the bottom layer and washed in PBS before being subjected to disruption of the granulocytes by a lysis buffer containing 10 mM Tris, pH 7.9, 10 mM KCl, 2 mM MgCl 2 , 0.1 mM EDTA, and 0.7% NP-40.…”

Section: Methodsmentioning

confidence: 99%

Higher Spontaneous and TNFα-Induced Apoptosis of Neonatal Blood Granulocytes

Liu

Wang

et al. 2005

Pediatr Res

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Granulocytes play an important role in inflammatory diseases. Neonates tend to develop granulocytopenia under sepsis and stress. It remains unclear whether apoptosis of neonatal granulocytes is different from that of adult granulocytes. In this study, we analyzed the discrepancy of granulocyte apoptosis between cord blood (CB) and adult blood (AB). We found that spontaneous and tumor necrosis factor-␣ (TNF␣)-induced granulocyte apoptosis as determined by phosphatidylserine expression and DNA fragmentation were more prominent in CB granulocytes than AB granulocytes. CD95 ligand and TNF␣ levels were significantly higher in CB than in AB (p ϭ 0.001 and p Ͻ 0.001, respectively). TNF receptor-2 and CD95 expression on CB granulocytes were not different from those on AB granulocytes. However, the TNF receptor-1 (TNFR1) expression was lower on CB granulocytes than that on AB granulocytes (69.98 Ϯ 7.32 versus 89.04 Ϯ 3.73%, p ϭ 0.029). This decrease of TNFR1 expression on neonatal granulocytes might be related to a higher plasma TNF␣ level associated with an intrinsic defect on the dynamic change of membrane TNFR1 expression in neonatal granulocytes. The expression of anti-apoptotic molecule Bcl-2 in neonatal granulocytes was also lower than that in adult granulocytes (4.64 Ϯ 0.51 versus 7.24 Ϯ 1.17 unit/mg protein, p ϭ 0.032). Moreover, another anti-apoptotic signal, nuclear factor-B nuclear translocation, was also lower in CB than AB granulocytes. Results from this study suggest that higher plasma death ligands associated with lower anti-apoptotic molecules in granulocytes may act an important role in triggering neonatal granulocyte apoptosis. Granulocytes play an important role in inflammatory diseases and provide a first-line defense against bacterial infections. They, however, have a short life span, about 6 h, and rapidly undergo apoptosis in blood circulation (1). Granulocytopenia is a poor prognostic factor for patients in neonatal intensive care units (2). It is known that the counter-regulation between apoptotic and anti-apoptotic signals determines the death program of granulocytes (3,4). It is not known whether abnormal plasma death ligands or intracellular anti-apoptotic molecules are involved in the susceptibility of granulocyte apoptosis in neonates.Newborns tend to develop granulocytopenia in overwhelming infections or stress. Certain studies have indicated that neonatal leukocytes are functionally immature and have deficient immune responses compared with adult ones (5,6). However, some studies demonstrated that the immune responses of newborns are similar to those of adults but are diminished under stress (7). It remains unclear whether susceptibility to granulocytopenia in neonates is related to faster cell program death (apoptosis) or to stress-induced alteration and consumption. Allgaier et al. (8) reported that neonatal granulocytes underwent apoptosis slower than adult ones. In contrast, Uguz et al. (9) found that granulocytes from neonates underwent faster apoptosis than adult granulocytes. The...

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A Model to Study Antioxidant Regulation of Endotoxemia-Modulated Neonatal Granulopoiesis and Granulocyte Apoptosis

Cited by 15 publications

References 32 publications

Apoptotic Changes in the Early Diagnosis and Severity Determination of Neonatal Sepsis

Apoptotic Changes in the Early Diagnosis and Severity Determination of Neonatal Sepsis

Vitamin D enhances reactive oxygen intermediates production in phagocytic cells in term and preterm infants

Higher Spontaneous and TNFα-Induced Apoptosis of Neonatal Blood Granulocytes

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