Assessment of DNA damage and plasma catalase activity in healthy term hyperbilirubinemic infants receiving phototherapy

Association between neonatal phototherapy and future cancer: an updated systematic review and meta-analysis

Phototherapy is the main treatment of neonatal hyperbilirubinemia to prevent encephalopathy. It is generally believed to be safe; however, some studies have shown it might be associated with cancer development. In this systematic review and meta-analysis, we aimed to assess the effect of neonatal phototherapy on future cancer risk. A systematic search in 13 databases was conducted in December 2018 and updated in August 2022 to identify studies that report cancer development after exposure to phototherapy. Throughout the study period, regular manual searches were also conducted to include new studies. A meta-analysis using R programming language was done in which the odds ratios (ORs) with 95% confidence intervals (CIs) were estimated and pooled using the reported adjusted and unadjusted data. Fifteen studies were included. A statistically significant association was detected between neonatal phototherapy and any type of cancer (OR 1.24; 95% CI 1.1, 1.4), any hematopoietic cancer (OR 1.49; 95% CI 1.17, 1.91), any leukemia (OR 1.35; 95% CI 1.08, 1.67), and myeloid leukemia (OR 2.86; 95% CI 1.4, 5.84). The other investigated cancers (lymphoid leukemia, Hodgkin's lymphoma, kidney cancer, nervous system cancer, and skin cancer) were not associated with phototherapy.  Conclusions: Phototherapy may carry a possible risk of future cancers. Future research is needed to quantify the magnitude of the cancer risk. These future studies should consider predictors of preterm birth or exclude premature babies from their analysis. What is Known • There were various reports about the possible association between phototherapy in neonates and the increased risk of cancer in the future. What is New • A statistically significant association between phototherapy and various hematopoietic cancers (especially myeloid leukemia) was recorded. • The effect of the duration of phototherapy on the increased risk of hematopoietic cancers is yet unclear.

Role of phototherapy, BAX gene expression in hyperbilirubinemia development in full-term neonates

Background

Phototherapy is the main therapeutic interference for neonatal hyperbilirubinemia used to escape an exchange transfusion and to decrease the risk of bilirubin-induced encephalopathy (kernikterus). Phototherapy has an oxidative effect on cell components and cell membranes by enhancing peroxidation of lipid and damage to DNA. Many genes function as apoptosis regulatory genes. Examples of these genes involve the BCL2 gene as an anti-apoptotic oncogene, and the BAX gene which is a promoter of apoptosis.

We aimed to evaluate the effect of phototherapy on expression of BAX and Bcl2 genes in hyperbilirubinemic full-term neonates.

Eighteen full-term neonates with indirect hyperbilirubinemia who received phototherapy for 24 h were enrolled as a study group and nine apparently healthy full-term neonates with a normal serum bilirubin level were included as a control group. Assessment of the anti-apoptotic effect(s) of BCL2 and the pro-apoptotic effect(s) of (Bax) genes was achieved by quantitative assay of their products (BCL2 and BAX proteins) by ELISA assay after phototherapy.

Results

Significant decrease in the bcl2 (p < 0.001) and increase in Bax protein (p < 0.001) serum levels after phototherapy in hyperbilirubinemic full-term neonates.

Conclusion

Hyperbilirubinemia has no apoptotic influence, while phototherapy induces apoptosis in the peripheral blood of hyperbilirubinemic full-term infants.

Cycled Phototherapy Dose-Finding Study for Extremely Low-Birth-Weight Infants: A Randomized Clinical Trial

Importance

Cycled (intermittent) phototherapy (PT) might adequately control peak total serum bilirubin (TSB) level and avoid mortality associated with usual care (continuous PT) among extremely low-birth-weight (ELBW) infants (401-1000 g).

Objective

To identify a cycled PT regimen that substantially reduces PT exposure, with an increase in mean peak TSB level lower than 1.5 mg/dL in ELBW infants.

Design, Setting, and Participants

This dose-finding randomized clinical trial of cycled PT vs continuous PT among 305 ELBW infants in 6 US newborn intensive care units was conducted from March 12, 2014, to November 14, 2018.

Interventions

Two cycled PT regimens (≥15 min/h and ≥30 min/h) were provided using a simple, commercially available timer to titrate PT minutes per hour against TSB level. The comparator arm was usual care (continuous PT).

Main Outcomes and Measures

Mean peak TSB level and total PT hours through day 14 in all 6 centers and predischarge brainstem auditory-evoked response wave V latency in 1 center. Mortality and major morbidities were secondary outcomes despite limited power.

Results

Consent was requested for 452 eligible infants and obtained for 305 (all enrolled) (mean [SD] birth weight, 749 [152] g; gestational age, 25.7 [1.9] weeks; 81 infants [27%] were multiple births; 137 infants [45%] were male; 112 [37%] were black infants; and 107 [35%] were Hispanic infants). Clinical and demographic characteristics of the groups were similar at baseline. After a preplanned interim analysis of 100 infants, the regimen of 30 min/h or more was discontinued, and the study proceeded with 2 arms. Comparing 128 infants receiving PT of 15 min/h or more with 128 infants receiving continuous PT among those surviving to 14 days, mean peak TSB levels were 7.1 vs 6.4 mg/dL (adjusted difference, 0.7; 95% CI, 0.4-1.1 mg/dL) and mean total PT hours were 34 vs 72 (adjusted difference, -39; 95% CI, -45 to -32). Wave V latency adjusted for postmenstrual age was similar in 37 infants receiving 15 min/h or more of PT and 33 infants receiving continuous PT: 7.42 vs 7.32 milliseconds (difference, 0.10; 95% CI, -0.11 to 0.30 millisecond). The relative risk for death was 0.79 (95% CI, 0.40-1.54), with a risk difference of -4.5% (95% CI, -10.9 to 2.0). Morbidities did not differ between groups.

Conclusions and Relevance

Cycled PT can substantially reduce total PT with little increase in peak TSB level. A large, randomized trial is needed to assess whether cycled PT would increase survival and survival without impairment in small, preterm infants.

Trial Registration

ClinicalTrials.gov Identifier: NCT01944696.

Effect of Purgative Manna on Neonatal Hyperbilirubinemia: A Systematic Review and Meta-analysis

The aim of this systematic review was to evaluate the effect of purgative manna on the unconjugated hyperbilirubinemia in neonates. Pubmed, Scopus, Chochrane library, Iranmedex and Google scholar were last searched in February 2017. Randomized controlled trials that evaluated the effect of purgative manna on the treatment of neonatal hyperbilirubinemia were included in the review. For meta-analysis, weighted mean difference (WMD) with 95% confidence interval (CI) was used. The outcomes of interests were serum bilirubin levels and length of hospital stay in neonates with jaundice. Seven randomized controlled trials with 812 neonates were eligible to be included in this systematic review. The meta-analysis included six of seven controlled trials. Bilirubin levels were significantly lower at 12 h (WMD: -1.48, 95% CI: -2.31 to -0.65), 24 h (WMD: -2.47, 95% CI: -3.22 to -1.71), 36 h (WMD: -2.83, 95% CI: -4.87 to -0.80), 48 h (WMD: -1.49, 95% CI: -2.36 to -0.63) and 72 h (WMD: -0.68, 95% CI: -1.28 to -0.08) following intervention in purgative manna group. Length of hospital stay was also decreased in purgative manna group (WMD: -0.93, 95% CI: -1.35 to -0.50). Finally, purgative manna administration decreased serum bilirubin level and length of hospital stay in neonates with unconjugated hyperbilirubinemia. More studies are needed to evaluate the efficacy, dosage, and side effects of purgative manna.

Effect of phototherapy on oxidant/antioxidant status: a randomized controlled trial

In order to evaluate the effect of different types of phototherapy on oxidant/antioxidant status in hyperbilirubinemic neonates, an interventional randomized control trial was conducted on 120 neonates ≥35 weeks' gestational age with indirect hyperbilirubinemia reaching phototherapy level. This study is registered with ClinicalTrials.gov as NCT03074292. Neonates were assigned to three groups; 40 neonates received conventional phototherapy, 40 received intensive phototherapy and 40 received blue light-emitting diodes (LED) phototherapy. Complete blood count (CBC), total serum bilirubin (TSB), total antioxidant capacity (TAC), malondialdehyde (MDA), nitric oxide (NO), copper (Cu), zinc (Zn), and iron (Fe) levels were measured before and 24 hours after phototherapy. TSB decreased postphototherapy in all three groups (p < .05 for all), with significantly lower levels following intensive and LED phototherapy compared to conventional phototherapy (p < .05 for both). TAC decreased postphototherapy in the three groups (p < .05 for all). MDA and NO increased postphototherapy (p < .05 for all), with the intensive phototherapy group having the highest levels followed by the conventional while LED phototherapy group showed the lowest levels in comparison to the other groups (p < .05). Cu, Zn and Fe increased postphototherapy in all three groups (p < .05 for all). Positive correlations were found between postphototherapy TSB with TAC, Cu and Zn (p < .05) and negative correlations with MDA, NO and Fe (p < .05) among neonates of the 3 studied groups. In conclusion, different photo therapies have an impact on oxidant/antioxidant balance and are associated with increased oxidative stress markers with the LED phototherapy being the safest.

Bilirubin-Induced Oxidative Stress Leads to DNA Damage in the Cerebellum of Hyperbilirubinemic Neonatal Mice and Activates DNA Double-Strand Break Repair Pathways in Human Cells

Unconjugated bilirubin is considered a potent antioxidant when present at moderate levels. However, at high concentrations, it produces severe neurological damage and death associated with kernicterus due to oxidative stress and other mechanisms. While it is widely recognized that oxidative stress by different toxic insults results in severe damage to cellular macromolecules, especially to DNA, no data are available either on DNA damage in the brain triggered by hyperbilirubinemia during the neonatal period or on the activation of DNA repair mechanisms. Here, using a mouse model of neonatal hyperbilirubinemia, we demonstrated that DNA damage occurs in vivo in the cerebellum, the brain region most affected by bilirubin toxicity. We studied the mechanisms associated with potential toxic action of bilirubin on DNA in in vitro models, which showed significant increases in DNA damage when neuronal and nonneuronal cells were treated with 140 nM of free bilirubin (Bf), as determined by γH2AX Western blot and immunofluorescence analyses. Cotreatment of cells with N-acetyl-cysteine, a potent oxidative-stress inhibitor, prevented DNA damage by bilirubin, supporting the concept that DNA damage was caused by bilirubin-induced oxidative stress. Bilirubin treatment also activated the main DNA repair pathways through homologous recombination (HR) and nonhomologous end joining (NHEJ), which may be adaptive responses to repair bilirubin-induced DNA damage. Since DNA damage may be another important factor contributing to neuronal death and bilirubin encephalopathy, these results contribute to the understanding of the mechanisms associated with bilirubin toxicity and may be of relevance in neonates affected with severe hyperbilirubinemia.

An Increased Genotoxic Risk in Lymphocytes from Phototherapy-Treated Hyperbilirubinemic Neonates

BACKGROUND

Phototherapy is believed to be a safe method for the management of hyperbilirubinemia. However, there are some controversial issues regarding the genotoxic effects of phototherapy on DNA. The aim of this study was to investigate morphologically both phototherapy-induced DNA double-strand breaks (DSBs) and apoptosis in lymphocytes derived from jaundiced and non-jaundiced neonates.

METHODS

Newborns were divided into three groups, including phototherapy-treated (PT, n=30) jaundiced newborns with total serum bilirubin (TSB) levels >15 mg/dl, non-treated jaundiced newborns (C+, n=27), as positive, as well as healthy negative (C-, n=30) controls with TSB levels ranging from 10 and 15 mg/dl and less than 5 mg/dl, respectively. Lymphocytes were isolated from whole blood samples by Ficoll-isopaque density gradient centrifugation and then assessed for DNA damage and apoptosis before and 24 hours after incubation at 37°C in 5% CO2 using the neutral comet assay.

RESULTS

DSB levels were significantly much higher in the PT group compared to the controls before incubation but decreased remarkably after the incubation period. As expected, no statistical differences were found between the two control groups before and after incubations. The frequency of apoptotic cells showed no significant differences among all the three groups before incubation; however, it was significantly increased in the PT group after incubation.

CONCLUSION

It seems that phototherapy in jaundiced infants is able not only to induce apoptosis in newborn lymphocytes but also to affect indirectly DNA integrity.

Jaundice, phototherapy and DNA damage in full-term neonates

OBJECTIVE

Phototherapy is the standard therapeutic approach for neonatal hyperbilirubinemia. Oxidative effects of phototherapy may have potential harms, including DNA damage. Unconjugated bilirubin (UCB) might also possess antigenotoxic potential. Intensive phototherapy is more efficacious than conventional phototherapy in treating hyperbilirubinemia. This study aimed to assess the impact of hyperbilirubinemia and the two different types of phototherapy on DNA damage in peripheral blood mononuclear cells of neonates.

STUDY DESIGN

The study was conducted on term neonates with non-hemolytic hyperbilirubinemia and control healthy neonates. Genotoxicity was assessed using single-cell gel electrophoresis (Comet assay) in peripheral mononuclear cells. Blood samples were obtained at enrollment in all infants and after intensive or conventional phototherapy in jaundiced infants.

RESULT

DNA damage did not significantly differ between jaundiced and non-jaundiced neonates (11.4±8.7 and 10.9±8.3 arbitrary units (AU), respectively, P=0.58). It increased significantly after exposure to phototherapy compared with prephototherapy values (45.6±14.7 vs 11.4±8.7 AU, respectively, P<0.001). The duration of phototherapy correlated positively with markers of DNA damage (r=0.86, P<0.001); however, the intensity of used light did not significantly impact genotoxicity.

CONCLUSION

Hyperbilirubinemia does not influence DNA damage, whereas both conventional and intensive phototherapy are associated with DNA damage in term infants with hyperbilirubinemia.

Influence of hyperbilirubinemia and phototherapy on markers of genotoxicity and apoptosis in full-term infants

Concerns of possible genotoxic effects of hyperbilirubinemia and phototherapy were raised from experimental and observational studies in neonates. This study aimed to assess the impact of hyperbilirubinemia and phototherapy on DNA damage and apoptosis in peripheral blood lymphocytes in healthy full-term infants. This study was conducted in the Children's Hospital, Mansoura University. Patients enrolled in this study were classified into three groups (each with 45 full-term infants): group 1 was composed of infants with hyperbilirubinemia requiring phototherapy, group 2 infants with physiological jaundice not requiring phototherapy, and group 3 infants without clinical jaundice. All enrolled infants were subjected to assessment of DNA damage and apoptosis in peripheral blood lymphocytes, using the comet assay and P53 by flow cytometry, consecutively. In group 1, measurements were done twice, before starting phototherapy and just before its discontinuation. DNA damage was not significantly different in the three groups, but it significantly increased after exposure to phototherapy compared to pre-phototherapy levels. There was no significant difference in P53 level in the three groups; however, it significantly increased after exposure to phototherapy. There were significant positive correlations between the duration of phototherapy and markers of DNA damage and apoptosis.

CONCLUSIONS

Hyperbilirubinemia does not influence DNA damage and apoptosis, whereas phototherapy causes DNA damage and induces apoptosis in peripheral blood lymphocytes of full-term infants.

Synthesis and biological evaluation of isoindoloisoquinolinone, pyroloisoquinolinone and benzoquinazolinone derivatives as poly(ADP-ribose) polymerase-1 inhibitors

A series of novel fused isoquinolinones with isoindoloisoquinolinone, pyroloisoquinolinone, and benzoquinalizinone skeletons were synthesized from corresponding phenethylimides. The isoquinolinone derivatives were evaluated for their protective effect on chicken erythrocytes subjected to oxidative damage. The effect of isoquinolinone derivatives were analysed by estimation of cell viability, antioxidant enzyme activities, DNA damage (comet assay), PARP-1 inhibition assay and molecular docking of the compounds with PARP-1 active site. The compounds CRR-271, CRR-288 and CRR-224+225 showed significant protective effect at 100 μM concentration. The PARP-1 inhibition assay revealed the IC50 values of CRR-271, CRR-288 and CRR-224+225 as <200 nM, further molecular docking studies shows higher binding energies with PARP-1 active site. Interesting findings in this study suggest that the novel isoquinolinone derivatives inhibit PARP-1 activity and protect cells against oxidative DNA damage, which could be implemented in the treatment of inflammatory diseases.

Lipid peroxidation, DNA damage and total antioxidant status in neonatal hyperbilirubinemia

OBJECTIVE

Lipid peroxidation, DNA damage and total antioxidant status (TAS) were assessed in neonates with unconjugated hyperbilirubinemia (UCH).

STUDY DESIGN

Plasma malondialdehyde (MDA), 8-hydroxy-2-deoxy-guanosine (8-OH-dG) and TAS levels were compared between 64 term newborns with idiopathic UCH and 30 age-matched healthy controls.

RESULT

Compared with controls, an overall increase in mean plasma MDA and 8-OH-dG levels and a decrease in TAS level were noted in the UCH group. Within the UCH group, mean plasma MDA level was found to be low in infants with lower bilirubin levels, but a progressive increase was documented above the bilirubin level of 20 mg dl(-1). A significant increase in 8-OH-dG level was documented even at lower bilirubin levels, and a decrease i plasma TAS level was found at bilirubin levels above 16 mg dl(-1). MDA and 8-OH-dG levels were significantly higher, whereas TAS level was significantly lower in five neonates who developed features of acute bilirubin encephalopathy compared with those with normal outcome. Alteration of MDA, 8-OH-dG and TAS levels showed high predictive accuracy for poor outcome.

CONCLUSION

Moderate-to-severe UCH was associated with higher oxidative stress and lower antioxidant defense. Alteration of oxidative stress parameters may be utilized as early predictors for poor outcome. High DNA damage even at lower bilirubin levels suggests possible genotoxic effect of bilirubin in UCH.