Understanding severe hyperbilirubinemia and preventing kernicterus: Adjuncts in the interpretation of neonatal serum bilirubin

Novel Two-Infusion Pump Technique for Exchange Transfusion in a Hyperbilirubinemic Neonate

Neonatal hyperbilirubinemia is a common concern in newborns, with ABO blood group incompatibility serving as a significant risk factor for severe jaundice. This case report outlines the successful management of a 2.5 kg female infant born to a primigravida mother with ABO incompatibility-induced hyperbilirubinemia. The neonate, born at 38.4 weeks via lower segment cesarean section, exhibited signs of jaundice at 91 hours of life, prompting screening and subsequent confirmation of serum bilirubin levels 26.4. The decision was made using the American Academy of Pediatrics (AAP) and categorized the child under high risk according to age and bilirubin level to implement a complete exchange transfusion using a novel approach with two infusion pumps. The unique aspect of this case lies in introducing a two-infusion pump technique, one to infuse and one to extract blood by inserting the IV set in opposite directions in the infusion pump to perform the exchange transfusion, aiming to minimize complications associated with traditional methods. Careful handling of umbilical venous and arterial lines, coupled with aseptic precautions, sought to mitigate the risk of sepsis. The procedure, conducted over two hours, demonstrated stability in vital signs and was monitored with a transcutaneous bilirubinometer. Post-transfusion, repeat serum bilirubin tests showed a decrease in bilirubin of 10.1, indicating the success of the novel exchange transfusion method. The infant was discharged after a five-day hospital stay, showcasing this innovative approach's potential efficacy and safety. This case contributes to the evolving strategies in neonatal care and emphasizes the importance of tailored interventions in managing hyperbilirubinemia associated with ABO incompatibility.

Clinical value of combination detection of direct antiglobulin test and serum albumin globulin ratio in severe hyperbilirubinemia caused by ABO hemolytic disease of the newborn

Background To explore of a combination of antiglobulin test(DAT) and albumin globulin ratio(AGR) could predict the severity of ABO hemolytic disease of the newborn(ABO-HDN).Methods The measurement of DAT, AGR and combination detection of DAT and AGR was done to predict severe ABO-HDN hyperbilirubinemia in 270 full-term infants based on whether the infants received transfusions of blood components. The infants were divided into three groups according to the results of DAT and ARG and compared the differences of phototherapy day and hospitalization day of the three groups.Results Of the 270 cases enrolled in this study, 69 infants were DAT positive. Peak total bilirubin, AGR, and positive DAT were independently associated with the need for blood components transfusion. ROC curve analysis for blood components transfusion showed that DAT cutoff value >± with a sensitivity of 39.4% and a specificity of 83.9%, AGR cutoff value <2.05 with a sensitivity of 54.1% and a specificity of 85.7%, and combination detection of DAT and ARG with a sensitivity of 62.1% and a specificity of 91.2%. The AUCs for DAT, AGR, and combination detection of DAT and AGR were .621, .740, and .750 respectively. The phototherapy day and hospitalization day were significantly longer in group of AGR <2.05 and DAT >± than that of a group of AGR <2.05 and group of DAT >±.Conclusions DAT and ARG could be early predictors for the severity ABO-HDN hyperbilirubinemia and combination detection of DAT and AGR could further increase its predictive value.

Effects of Repetitive Transcranial Magnetic Stimulation on Pallidum GABAergic Neurons and Motor Function in Rat Models of Kernicterus

Kernicterus is a serious complication of hyperbilirubinemia, caused by neuronal injury due to excessive unconjugated bilirubin (UCB) in specific brain areas. This injury induced by this accumulation in the globus pallidus can induce severe motor dysfunction. Repetitive transcranial magnetic stimulation (rTMS) has shown neuroprotective effects in various neurological diseases. This study aimed to investigate the effects of rTMS on pallidal nerve damage and motor dysfunction in a rat model of kernicterus. Rats were divided into a sham group (n = 16), a model group (bilirubin with sham rTMS; n = 16) and an rTMS group (bilirubin with rTMS; n = 16). High-frequency rTMS (10 Hz) was applied starting from 24 h postmodeling for 7 days. The rotarod test, western blotting and immunohistochemical staining were performed to measure motor function and protein expression levels. The rTMS mitigated the negative effects of UCB on the general health of kernicterus-model rats and improved their growth and development. Furthermore, the rTMS alleviated UCB-induced motor dysfunction and increased the expression of GABAergic neuronal marker GAD67 in the globus pallidus. Notably, it also inhibited apoptosis-related protein caspase-3 activation. In conclusion, rTMS could alleviate motor dysfunction by inhibiting apoptosis and increasing globus pallidus GAD67 in kernicterus rat models, indicating that it may be a promising treatment for kernicterus.

Bilirubin Encephalopathy

PURPOSE OF REVIEW

Hyperbilirubinemia is commonly seen in neonates. Though hyperbilirubinemia is typically asymptomatic, severe elevation of bilirubin levels can lead to acute bilirubin encephalopathy and progress to kernicterus spectrum disorder, a chronic condition characterized by hearing loss, extrapyramidal dysfunction, ophthalmoplegia, and enamel hypoplasia. Epidemiological data show that the implementation of universal pre-discharge bilirubin screening programs has reduced the rates of hyperbilirubinemia-associated complications. However, acute bilirubin encephalopathy and kernicterus spectrum disorder are still particularly common in low- and middle-income countries.

RECENT FINDINGS

The understanding of the genetic and biochemical processes that increase the susceptibility of defined anatomical areas of the central nervous system to the deleterious effects of bilirubin may facilitate the development of effective treatments for acute bilirubin encephalopathy and kernicterus spectrum disorder. Scoring systems are available for the diagnosis and severity grading of these conditions. The treatment of hyperbilirubinemia in newborns relies on the use of phototherapy and exchange transfusion. However, novel therapeutic options including deep brain stimulation, brain-computer interface, and stem cell transplantation may alleviate the heavy disease burden associated with kernicterus spectrum disorder. Despite improved screening and treatment options, the prevalence of acute bilirubin encephalopathy and kernicterus spectrum disorder remains elevated in low- and middle-income countries. The continued presence and associated long-term disability of these conditions warrant further research to improve their prevention and management.

Surface-Enhanced Raman Scattering-Active Gold-Decorated Silicon Nanowire Substrates for Label-Free Detection of Bilirubin

Bilirubin (BR) is a product of hemoglobin breakdown, and its increasing levels in the blood may indicate liver disorders and lead to jaundice. Kernicterus is most dangerous in newborns when the unconjugated BR concentration can quickly rise to toxic levels, causing neurological damage and even death. The development of an accurate, fast, and sensitive sensor for BR detection will help reduce diagnostic time and ensure successful treatment. In this study, we propose a new method for creating a surface-enhanced Raman scattering (SERS)-active substrate based on gold-decorated silicon nanowires (Au@SiNWs) for sensitive label-free BR detection. Gold-assisted chemical etching of crystalline silicon wafers was used to synthesize SiNWs, the tops of which were then additionally decorated with gold nanoparticles. The low detection limit of model analyte 4-mercaptopyridine down to the concentration of 10^-8 M demonstrated the excellent sensitivity of the obtained substrates for SERS application. The theoretical full-wave electromagnetic simulations of Raman scattering in the Au@SiNW substrates showed that the major contribution to the total SERS signal comes from the analyte molecules located on the SiNW surface near the gold nanoparticles. Therefore, for efficient BR adsorption and SERS detection, the surface of the SiNWs was modified with amino groups. Label-free detection of BR using amino modified Au@SiNWs with high point-to-point, scan-to-scan, and batch-to-batch reproducibility with a detection limit of 10^-6 M has been demonstrated. Artificial urine, mimicking human urine samples, was used as the matrix to get insights into the influence of different parameters such as matrix complexity on the overall BR SERS signal. The signal stability was demonstrated for 7 days after adsorption of BR with a concentration of 5 × 10^-5 M, which is the required sensitivity for clinical applications.

Direct antiglobulin test in the prediction of hyperbilirubinemia and predischarge bilirubin levels in infants with mother-infant blood type incompatibility

BACKGROUND

This research evaluated the association between the mother-infant blood type or rhesus (ABO or Rh) incompatibility, the pattern of neonatal jaundice, and serum bilirubin (TSB) values obtained prior to discharge from hospital of healthy born neonates with gestational age >34 weeks and birth weight >2000 g.

METHODS

We utilized a laboratory and neonatal database to identify the cord blood ABO/Rh and direct antiglobulin test (DAT) and TSB measured during hospitalization and re-admission with hyperbilirubinemia for phototherapy treatment. We used hour-specific TSB to analyze the TSB levels for ABO/Rh compatibility and isoimmunization using chi-square, analysis of variance, and regression models.

RESULTS

Of the 901 infants studied, 158 (17.5%) had ABO/Rh incompatibility, including 27 with positive DAT. Hyperbilirubinemia was diagnosed in 33.3% DAT positive, 6.9% DAT negative, and 4.6% of infants with compatible blood types. Increased predischarge TSB was observed in DAT positive infants at 48-72 h of postnatal age (P < 0.001). After controlling for age at TSB testing and weight loss percentage, multiple regression analysis did not show any impact of ABO/Rh incompatibility and DAT results on the predischarge TSB levels.

CONCLUSION

Blood type incompatibility increases the frequency of hyperbilirubinemia only in the DAT-positive infants. Irrespective of the isoimmunization status, it does not significantly affect the level of predischarge TSB.

Optimization of zinc oxide nanoparticle-catalyzed in vitro bilirubin photolysis and in vivo treatment of hyperbilirubinemia

Aim: To optimize the Zinc oxide nanoparticles (ZnONPs)-catalyzed in vitro photolysis of bilirubin and to test their effect on bilirubin clearance in vivo. Materials & methods: ZnONPs, synthesized in an alkaline medium, were characterized. Response surface methodology was used to optimize the in vitro photolysis catalyzed by the nanoparticles (NPs). Blood samples from phenylhydrazine-induced hyperbilirubinemic rabbits which had been administered ZnONPs and UV light were analyzed to assess in vivo clearance of bilirubin. Results: The ZnONP-assisted UV treatment showed the linear and quadratic positive effects on the in vitro bilirubin photolysis with an optimal photolysis of bilirubin at 225 mg dl^-1 concentration of ZnONPs and a UV exposure of 1.80 h. The ZnONP-assisted phototherapy of hyperbilirubinemic animals was also found to be more effective for in vivo clearance of bilirubin than phototherapy alone. Conclusion: After further trials, ZnONP-assisted phototherapy could be a potential treatment for hyperbilirubinemia in humans.

Conjugate of pyrimidine derivative, the drug xymedon with succinic acid protects liver cells

The aim of the study was to investigate the hepatoprotective properties of the conjugate of the xymedon drug substance with succinic acid (1a). The study presents an in vitro comparative evaluation of the cytotoxicity and cytoprotective properties of 1a and succinic acid on a cell line of normal human hepatocytes Chang Liver, and in vivo investigation of the ability of 1a to restore liver from the toxic damage caused by CCl₄ in Wistar rats. It was shown that the cytotoxicity of 1a was 19.9 ± 0.8 mmol/L, and that of succinic acid was 14.1 ± 0.2 mmol/L. Against the background of d-galactosamine exposure, the cytoprotective effect of 1a was found to be superior to that of succinic acid. It was shown that 1a caused a significant reduction in necrotic and steatosis changes in the liver and restoration of biochemical markers of cytolysis, as well as bilirubin metabolism and synthetic liver function.

Manpower capacity and reasons for staff shortage in primary health care maternity centres in Nigeria: a mixed-methods study

Background

The heart-breaking maternal and neonatal health indicators in Nigeria are not improving despite previous interventions, such as ‘Health for all’ and ‘Millennium Development Goals. The unattained health-related goals/targets of previous interventions put the success of the new Sustainable Development Goals in doubt if the existing paradigm remains unchanged. Thus, mere branding of health policies without improving what constitutes the health system such as manpower capacity and quality as well as staff-patients ratio will be wasteful efforts. This issue of global public health concern provided an indication for describing the capacity of manpower and reasons for staff shortage in primary level of health that are providing maternity services to women and their new-borns in Nigeria.

Methods

This is an embedded mixed-methods study. Its quantitative strand collected data with the aid of a structured questionnaire from 127 health workers across the 21 purposively selected primary health care centres in five local government areas. Descriptive statistics were employed for analysis. The qualitative strand of the study collected data through in depth interviews from medical officers of health or their representatives. The tape recorded and transcribed data were thematically coded, while reporting was by direct quotes. The mixing of the data from both strands was done in the discussion section.

Results

Twenty-nine (22.8%) of the health workers were between ages 51–58; 111 (87.4%) were married, while 44 (34.6%) had worked for duration of 21–33 years in service. Evidences of incompetence were observed among the health workers. A total of 92 (72.4%) had been performing episiotomies on women in labour. Similarly, 69.8% had been repairing vaginal traumas. Nine (7.1%) knew the necessary steps of controlling postpartum vaginal bleeding, while 115 (91.3%) of them had not been trained in Life-Saving Scheme and post-abortions care.

Conclusion

The shortage of manpower, disproportional skilled/semi-skilled ratio, lack of framework for staff recruitment, staff incompetence and inappropriate childbirth practices show that women were not receiving quality maternal and neonatal cares at the maternity centres.

Fiber enhanced Raman spectroscopic analysis as a novel method for diagnosis and monitoring of diseases related to hyperbilirubinemia and hyperbiliverdinemia

Fiber enhanced resonance Raman spectroscopy (FERS) is introduced for chemically selective and ultrasensitive analysis of the biomolecules hematin, hemoglobin, biliverdin, and bilirubin. The abilities for analyzing whole intact, oxygenated erythrocytes are proven, demonstrating the potential for the diagnosis of red blood cell related diseases, such as different types of anemia and hemolytic disorders. The optical fiber enables an efficient light-guiding within a miniaturized sample volume of only a few micro-liters and provides a tremendously improved analytical sensitivity (LODs of 0.5 μM for bilirubin and 0.13 μM for biliverdin with proposed improvements down to the pico-molar range). FERS is a less invasive method than the standard ones and could be a new analytical method for monitoring neonatal jaundice, allowing a precise control of the unconjugated serum bilirubin levels, and therefore, providing a better prognosis for newborns. The potential for sensing very low concentrations of the bile pigments may also open up new opportunities for cancer research. The abilities of FERS as a diagnostic tool are explored for the elucidation of jaundice with different etiologies including the rare, not yet well understood diseases manifested in green jaundice. This is demonstrated by quantifying clinically relevant concentrations of bilirubin and biliverdin simultaneously in the micro-molar range: for the case of hyperbilirubinemia due to malignancy, infectious hepatitis, cirrhosis or stenosis of the common bile duct (1 μM biliverdin together with 50 μM bilirubin) and for hyperbiliverdinemia (25 μM biliverdin and 75 μM bilirubin). FERS has high potential as an ultrasensitive analytical technique for a wide range of biomolecules and in various life-science applications.

UGT1A1 gene and neonatal hyperbilirubinemia: a preliminary study from Bengkulu, Indonesia

Objective

The genetic involvement in unconjugated neonatal hyperbilirubinemia has been extensively studied. Despite the high incidence of hyperbilirubinemia in Indonesia, studies are lacking. The objective of this study is to elucidate the role of polymorphism in the UGT1A1 in Neonatal Hyperbilirubinemia in Bengkulu, Indonesia.

Results

There were 41 neonates enrolled in the study; 30 had a total serum bilirubin level ≥ 15 mg/dL (hyperbilirubinemia neonates) while 11 has < 15 mg/dL (control neonates). Genetic mutations in Exon 1, UGT1A1*6 (c211g > a) and one in promoter region, UGT1A1*60 (c3279t > g) were determined by polymerase chain reaction–restriction fragment length polymorphism. We found 18 (60%) mutation in exon 1 in hyperbilirubinemia group and 7 (64%) in the control group with an identical allele frequency of 0.3 in both groups. We found heterozygous UGT1A1*60 4 times (13.3%) and homozygous 26 times (86.7%) in the hyperbilirubinemia group, with an identical allele frequency of 0.935 in hyperbilirubinemia and 1 in control group. This study supports the involvement of genetic factors in the development of unconjugated hyperbilirubinemia in Bengkulu population.

Carboxyhemoglobin - the forgotten parameter of neonatal hyperbilirubinemia

BACKGROUND

Neonatal hyperbilirubinemia is influenced by a wide variety of factors, one of which is hemolysis. Serious hyperbilirubinemia may lead to a kernicterus with detrimental neurologic sequelae. Patients suffering from hemolytic disease have a higher risk of developing kernicterus. Carbon monoxide (CO), a byproduct of hemolysis or heme degradation, was described by Sjöstrand in the 1960s. It is transported as carboxyhemoglobin (COHb) and exhaled through the lungs. We were interested in a potential correlation between COHb and total serum bilirubin (TSB) and the time course of both parameters.

MATERIALS AND METHODS

We used a point of care (POC) blood gas analyzer and did a retrospective analysis of bilirubin and COHb data collected over a 60-day period.

RESULTS

An arbitrary cut-off point set at 2% COHb identified four patients with hemolytic disease of different origins who required phototherapy. In one patient with atypical hemolytic uremic syndrome (aHUS), COHb preceded the rise in bilirubin by about 2 days. Despite this displacement, there was a moderately good correlation of COHb with TSB levels <15 mg/dL (257 μmol/L) (r2: 0.80) and direct bilirubin (r2: 0.78) in the first patient. For all the four patients and all time points the correlation was slightly lower (r2: 0.59).

CONCLUSIONS

COHb might be useful as a marker for high hemoglobin turnover to allow an earlier identification of newborns at risk to a rapid rise in bilirubin.

Relationship between transcutaneous bilirubin and circulating unbound bilirubin in jaundiced neonates

BACKGROUND

Transcutaneous bilirubin (TcB) consists of the skin-deposited bilirubin. Free bilirubin represents the protein-unbound bilirubin (UB) that is able to pass into the tissues. We aimed to describe the relationship UB-TcB and study the passage of UB into the skin.

METHODS

We prospectively enrolled 194 neonates and we measured TcB, UB, serum bilirubin and albumin. Multiple sites TcB measurement was performed, bilirubin-albumin equilibrium constant and plasma bilirubin avidity (PBA) were calculated.

RESULT

TcB has a similar correlation with UB and TSB. There is a quadratic relationship between UB and TcB (R²=0.48; p<0.001), remaining significant (β for UB²=-0.8; p<0.001. β for UB=1.1; p<0.001) after adjustment for gestational age, birth weight, postnatal age and albumin (Adj-R²=0.72). UB contributes to the skin bilirubin deposition, as there are significant correlations between albumin and TcB (r=-0.202; p=0.01) and between PBA and ΔTcB (r=0.323; p=0.017).

CONCLUSION

TcB assay does not seem to directly replace UB measurement. However, TcB and UB are linked by a quadratic relationship: UB contributes to the skin bilirubin deposition but it is not the only bilirubin species measured by transcutaneous bilirubinometry.

Glucose-6-Phosphate Dehydrogenase Deficiency and the Need for a Novel Treatment to Prevent Kernicterus

Hyperbilirubinemia occurs frequently in newborns, and in severe cases can progress to kernicterus and permanent developmental disorders. Glucose-6-phosphate dehydrogenase (G6PD) deficiency, one of the most common human enzymopathies, is a major risk factor for hyperbilirubinemia and greatly increases the risk of kernicterus even in the developed world. Therefore, a novel treatment for kernicterus is needed, especially for G6PD-deficient newborns. Oxidative stress is a hallmark of bilirubin toxicity in the brain. We propose that the activation of G6PD via a small molecule chaperone is a potential strategy to increase endogenous defense against bilirubin-induced oxidative stress and prevent kernicterus.

Optimization of phenylhydrazine induced hyperbilirubinemia in experimental rabbit

Induction of hyperbilirubinemia in experimental rabbits by phenylhydrazine was optimized in terms of dose, dose interval and number of doses using response surface methodology. Central Composite Design was employed using five levels for each of the three input variables. Degree of hyperbilirubinemia was measured in terms of bilirubin level in serum of animals. A dose dependent significant elevation (P<0.05) of total serum bilirubin level was observed which was optimized by using eight factorial, six axial and six central points as suggested by experimental design. Optimum levels of phenylhydrazine dose, total number of doses and a dose interval to achieve maximum elevation (4.06 mg/dl⁻¹) of total serum bilirubin were found to be 11.56 mg/kg⁻¹ body weight, 8 and 24.65 h, respectively. The induction procedure was validated by performing five replicate experiments on a group of five animals which showed 3.56 ± 0.47 mg/kg⁻¹ body weight elevation in total serum bilirubin level.

Hemolytic Disorders Causing Severe Neonatal Hyperbilirubinemia

A shortened erythrocyte life span, because of hemolytic disorders, is a common cause of extreme neonatal hyperbilirubinemia. Clinical and laboratory examinations can frequently identify the underlying cause of extreme neonatal hyperbilirubinemia. In this article, several tests, techniques, and approaches have been reviewed, including red blood cell morphology assessment, end-tidal carbon monoxide quantification, eosin-5-maleimide flow cytometry, as well as next-generation DNA sequencing using neonatal jaundice panels.

Cross-talk between neurons and astrocytes in response to bilirubin: adverse secondary impacts

Previous studies using monotypic nerve cell cultures have shown that bilirubin-induced neurological dysfunction (BIND) involves apoptosis and necrosis-like cell death, following neuritic atrophy and astrocyte activation,and that glycoursodeoxycholic acid (GUDCA) has therapeutic efficacy against BIND. Cross-talk between neurons and astrocytes may protect or aggravate neurotoxicity by unconjugated bilirubin (UCB). In a previous work we have shown that bidirectional signaling during astrocyte-neuron recognition attenuates neuronal damage by UCB. Here, we investigated whether the establishment of neuron-astrocyte homeostasis prior to cell exposure to UCB was instead associated with a lower resistance of neurons to UCB toxicity, and if the pro-survival properties of GUDCA were replicated in that experimental model. We have introduced a 24 h adaptation period for neuron-glia communication prior to the 48 h treatment with UCB. In such conditions, UCB induced glial activation, which aggravated neuronal damage, comprising increased apoptosis,cell demise and neuritic atrophy, which were completely prevented in the presence of GUDCA. Neuronal multidrug resistance-associated protein 1 expression and tumor necrosis factor-a secretion, although unchanged by UCB, increased in the presence of astrocytes. The rise in S100B and nitric oxide in the co-cultures medium may have contributed to UCB neurotoxicity. Since the levels of these diffusible molecules did not change by GUDCA we may assume that they are not directly involved in its beneficial effects. Data indicate that astrocytes, in an indirect neuron-astrocyte co-culture model and after homeostatic setting regulation of the system, are critically influencing neurodegeneration by UCB, and support GUDCA for the prevention of BIND.

Ex vivo (1)H nuclear magnetic resonance spectroscopy reveals systematic alterations in cerebral metabolites as the key pathogenetic mechanism of bilirubin encephalopathy

BACKGROUND

Bilirubin encephalopathy (BE) is a severe neurologic sequelae induced by hyperbilirubinemia in newborns. However, the pathogenetic mechanisms underlying the clinical syndromes of BE remain ambiguous. Ex vivo (1)H nuclear magnetic resonance (NMR) spectroscopy was used to measure changes in the concentrations of cerebral metabolites in various brain areas of newborn 9-day-old rats subjected to bilirubin to explore the related mechanisms of BE.

RESULTS

When measured 0.5 hr after injection of bilirubin, levels of the amino acid neurotransmitters glutamate (Glu), glutamine (Gln), and γ-aminobutyric acid (GABA) in hippocampus and occipital cortex significantly decreased, by contrast, levels of aspartate (Asp) considerably increased. In the cerebellum, Glu and Gln levels significantly decreased, while GABA, and Asp levels showed no significant differences. In BE 24 hr rats, all of the metabolic changes observed returned to normal in the hippocampus and occipital cortex; however, levels of Glu, Gln, GABA, and glycine significantly increased in the cerebellum.

CONCLUSIONS

These metabolic changes for the neurotransmitters are mostly likely the result of a shift in the steady-state equilibrium of the Gln-Glu-GABA metabolic cycle between astrocytes and neurons, in a region-specific manner. Changes in energy metabolism and the tricarboxylic acid cycle may also be involved in the pathogenesis of BE.

Hemolytic disease of the fetus and newborn caused by anti-E

Objective:

Maternal allo-antibody production is stimulated when fetal red blood cells are positive for an antigen absent on the mother's red cells. The maternal IgG antibodies produced will pass through the placenta and attack fetal red cells carrying the corresponding antigen. Allo-immune hemolytic disease of the fetus and newborn caused by anti-E rarely occurs.

Case summary:

We report two cases of anti-E hemolytic diseases in neonates. One of the neonates had severe hemolysis presenting with severe anemia, thrombocytopenia, and conjugated hyperbilirubinemia, while the other had moderate anemia and unconjugated hyperbilrubinemia. Although both the neonates were treated by phototherapy and intravenous immunoglobulin, one of them received double volume exchange transfusion.

Conclusion:

There appeared to be an increase in the occurrence of hemolytic disease of the fetus and newborn caused by Rh antibodies other than anti-D. In this case report, both patients presented with anemia and hyperbilirubinemia but were successfully treated, with a favorable outcome.

The evolving landscape of neurotoxicity by unconjugated bilirubin: role of glial cells and inflammation

Unconjugated hyperbilirubinemia is a common condition in the first week of postnatal life. Although generally harmless, some neonates may develop very high levels of unconjugated bilirubin (UCB), which may surpass the protective mechanisms of the brain in preventing UCB accumulation. In this case, both short-term and long-term neurodevelopmental disabilities, such as acute and chronic UCB encephalopathy, known as kernicterus, or more subtle alterations defined as bilirubin-induced neurological dysfunction (BIND) may be produced. There is a tremendous variability in babies' vulnerability toward UCB for reasons not yet explained, but preterm birth, sepsis, hypoxia, and hemolytic disease are comprised as risk factors. Therefore, UCB levels and neurological abnormalities are not strictly correlated. Even nowadays, the mechanisms of UCB neurotoxicity are still unclear, as are specific biomarkers, and little is known about lasting sequelae attributable to hyperbilirubinemia. On autopsy, UCB was shown to be within neurons, neuronal processes, and microglia, and to produce loss of neurons, demyelination, and gliosis. In isolated cell cultures, UCB was shown to impair neuronal arborization and to induce the release of pro-inflammatory cytokines from microglia and astrocytes. However, cell dependent sensitivity to UCB toxicity and the role of each nerve cell type remains not fully understood. This review provides a comprehensive insight into cell susceptibilities and molecular targets of UCB in neurons, astrocytes, and oligodendrocytes, and on phenotypic and functional responses of microglia to UCB. Interplay among glia elements and cross-talk with neurons, with a special emphasis in the UCB-induced immunostimulation, and the role of sepsis in BIND pathogenesis are highlighted. New and interesting data on the anti-inflammatory and antioxidant activities of different pharmacological agents are also presented, as novel and promising additional therapeutic approaches to BIND.

Birth-related syndromes of athetosis and kernicterus

"Athetosis," from the Greek athetos, meaning "without fixed position," is a movement disorder first described by Hammond in 1871. The term described slow, irregular continual movements of the distal extremities. In 1983, Foley defined the athetoid syndrome as "a nonprogressive but evolving disorder due to damage to the basal ganglia of the full-term brain … [with] impairment of postural reflexes, arrhythmical involuntary movements, and dysarthria, [but] sparing … sensation, ocular movements and … intelligence." A decade later, "athetoid syndrome" was replaced by "dyskinetic cerebral palsy." Injury to basal ganglia by various mechanisms, including asphyxia, trauma, perinatal strokes, and kernicterus, is known to cause birth-related athetosis. Kernicterus originally described the neuropathology of bilirubin-induced brain injury, where the deep nuclei of the brain stain yellow. Kernicterus now describes the clinical features of chronic bilirubin encephalopathy, which include an extrapyramidal movement disorder, sensorineural hearing loss, impaired upward gaze, and dental enamel dysplasia. Aggressive treatment of perinatal hyperbilirubinemia has led to a decline in kernicterus so that, today, it is a rare cause of dyskinetic cerebral palsy. In this chapter, we provide a historic overview of athetosis and its formerly common cause, kernicterus. We relate earlier terminology to more recent definitions of impairments in dyskinetic cerebral palsy, including dystonia, chorea, and choreoathetosis.

Bilirubin injury to neurons and glial cells: new players, novel targets, and newer insights

Encephalopathy by hyperbilirubinemia in infants has been described for decades, but neither the underlying cellular and molecular mechanisms nor the selective pattern of bilirubin deposition in the brain is well understood. The brain is composed of highly specialized and diverse populations of cells, represented by neurons and glia that comprise astrocytes, oligodendrocytes, and microglia. Although microscopic evaluation of icteric brain sections revealed bilirubin within neurons, neuronal processes, and microglia, cell dependent-sensitivity to bilirubin toxicity and the role of each nerve cell type are poorly understood. Even less considered are glial and neuronal pathologic alterations as integrated phenomena. The available knowledge on reactivity of glial cells to bilirubin and on the impairment to neuronal network dynamics that it causes, here summarized, suggests that a better comprehension of the interplay between neurons and glia is essential to understand bilirubin neurotoxicity and highlight potential molecular targets that may lead to disease-modifying therapeutic approaches.

Dynamics of neuron-glia interplay upon exposure to unconjugated bilirubin

Microglia are the main players of the brain immune response. They act as active sensors that rapidly respond to injurious insults by shifting into different activated states. Elevated levels of unconjugated bilirubin (UCB) induce cell death, immunostimulation and oxidative stress in both neurons and astrocytes. We recently reported that microglial phagocytic phenotype precedes the release of pro-inflammatory cytokines upon UCB exposure. We investigated whether and how microglia microenvironment influences the response to UCB. Our findings revealed that conditioned media derived from UCB-treated astrocytes reduce microglial inflammatory reaction and cell death, suggesting an attempt to curtail microglial over activation. Conditioned medium from UCB-challenged neurons, although down-regulating tumor necrosis factor-α and interleukin-1β promoted the release of interleukin-6 and nitric oxide, the activation of matrix metalloproteinase-9, and cell death, as compared with UCB-direct effects on microglia. Moreover, soluble factors released by UCB-treated neurons intensified the phagocytic properties manifested by microglia under direct exposure to UCB. Results from neuron-microglia mixed cultures incubated with UCB evidenced that sensitized microglia were able to prevent neurite outgrowth impairment and cell death. In conclusion, our data indicate that stressed neurons signal microglial clearance functions, but also overstimulate its inflammatory potential ultimately leading to microglia demise.

Evaluation of oxidant and antioxidant status in infants with hyperbilirubinemia and kernicterus

Objective: The objective of the present study was to determine oxidant and antioxidant status in infants with hyperbilirubinemia and/or kernicterus and to find whether there is a relationship between bilirubin level and oxidant/antioxidant status. Patients: The study includes 69 full-term newborns (neonates with hyperbilirubinemia needing phototherapy [Group 1, n = 36] and neonates with kernicterus [Group 2, n = 33]) and 25 age-matched healthy newborn. Results: Plasma total antioxidant capacity (TAC) and serum total oxidant status (TOS) were significantly higher in Groups 1 and 2 than the control group. There was a significant difference between Group 1 and control cases for malondialdehyde (MDA; p < 0.001). Total free sulfhydryl group (TTHI) values were significantly elevated in Group 1 compared to Group 2 and control cases. Correlation analysis showed that the correlation between total bilirubin (TB) and TAC, TOS, MDA and oxidative stress index may be expressed by a quadratic curve. After phototherapy, a statistically significant increase in nitrite level was observed. Conclusion: We demonstrated that the relationship between serum TB and antioxidants and oxidative stress could be expressed by a quadratic correlation curve.

Astrocyte reactivity to unconjugated bilirubin requires TNF-α and IL-1β receptor signaling pathways

Jaundice and sepsis are common neonatal conditions that can lead to neurodevelopment sequelae, namely if present at the same time. We have reported that tumor necrosis factor (TNF)-α and interleukin (IL)-1β are produced by cultured neurons and mainly by glial cells exposed to unconjugated bilirubin (UCB). The effects of these cytokines are mediated by cell surface receptors through a nuclear factor (NF)-κB-dependent pathway that we have showed to be activated by UCB. The present study was designed to evaluate the role of TNF-α and IL-1β signaling on astrocyte reactivity to UCB in rat cortical astrocytes. Exposure of astrocytes to UCB increased the expression of both TNF-α receptor (TNFR)1 and IL-1β receptor (IL-1R)1, but not TNFR2, as well as their activation, observed by augmented binding of receptors' molecular adaptors, TRAF2 and TRAF6, respectively. Silencing of TNFR1, using siRNA technology, or blockade of IL-1β cascade, using its endogenous antagonist, IL-1 receptor antagonist (IL-1ra), prevented UCB-induced cytokine release and NF-κB activation. Interestingly, lack of TNF-α signal transduction reduced UCB-induced cell death for short periods of incubation, although an increase was observed after extended exposure; in contrast, inhibition of IL-1β cascade produced a sustained blockade of astrocyte injury by UCB. Together, our data show that inflammatory pathways are activated during in vitro exposure of rat cortical astrocytes to UCB and that this activation is prolonged in time. This supports the concept that inflammatory pathways play a role in brain damage by UCB, and that they may represent important pharmacological targets.

[Preparation of bovine serum albumin immobilized adsorbent for specific adsorption of bilirubin]

Serum bilirubin concentration is greatly elevated in certain diseases such as hyperbilirubinemia and severe hepatitis. Lowering the level of bilirubin is one of the major targets of many therapies such as plasma exchange and hemoperfusion. In this study, a bilirubin specific adsorbent was prepared by covalently immobilizing bovine serum albumin (BSA) onto macroporous poly (glycidyl methacrylate-co-trimethylolpropane trimethacrylate) microspheres. The resulting BSA immobilized adsorbent (BIA) demonstrated good performance in adsorption of bilirubin with an adsorption capacity of 48.7 mg/g. Presence of BSA in bilirubin solution significantly lowered the adsorption capacity of the adsorbent due to the tight binding of bilirubin onto BSA. Adsorption performance of the adsorbent for bilirubin was improved with the elevation of temperature. The adsorbent demonstrated good stability even after 31 d of storage at - 80 degrees C in that there was almost no change in adsorption capacity for bilirubin. These results indicated that the prepared BSA immobilized adsorbent could be an alternative choice for specific adsorption of bilirubin.

Maternal IgG anti-A and anti-B titres predict outcome in ABO-incompatibility in the neonate

AIM

To evaluate predictors for risk of severe hyperbilirubinaemia and kernicterus in ABO-incompatible neonates with emphasize on maternal IgG anti-A/-B titres.

METHODS

Blood group O women in labour at Oslo University Hospital, Ullevål, were included in the years 2004-2006. Offspring with blood group A or B had direct antiglobulin test performed and IgG anti-A/-B levels measured in maternal plasma. Blood group A or B infants developing severe hyperbilirubinaemia, received in addition to phototherapy, immunoglobulin treatment and/or exchange transfusion (EXT).

RESULTS

Of 253 neonates, 61.3% had blood group O, 29.6% blood group A and 9.1% blood group B. Twenty neonates with blood group A or B received at least one immunoglobulin treatment. In multivariate analysis, maternal antibody-titres were the only significant predictors for immunoglobulin treatment (p < 0.0001), EXTs (p < 0.05) and duration of phototherapy (p < 0.0001). The need for invasive treatment increased sharply for antibody titres > or =512. Receiver operating characteristic analyses demonstrated that titres > or =512 had a sensitivity of 90% and a specificity of 72% for predicting immunoglobulin treatment and thus severe hyperbilirubinaemia.

CONCLUSION

Maternal IgG anti-A/-B titres contribute to the prediction of risk of severe hyperbilirubinaemia in ABO-incompatible neonates, in addition to blood-grouping and direct antiglobulin-testing, especially following early discharge after delivery.

Neonatal jaundice: a critical review of the role and practice of bilirubin analysis

Neonatal jaundice is common, and usually harmless, because of physiological jaundice or breast-feeding. In some neonates unconjugated bilirubin concentration, coupled with other risk factors, is sufficient to allow free bilirubin to cross the blood-brain barrier and cause kernicterus. Another subgroup of infants is jaundiced because of elevated conjugated bilirubin; a marker for a number of pathological conditions. Bilirubin measurement must identify those infants at risk. Transcutaneous bilirubin measurement is increasingly used in healthy infants, especially before early discharge or at home, to assess the need for laboratory bilirubin measurement. Transcutaneous measurements are not covered by laboratory quality assessment schemes. Guidelines on management of neonatal jaundice utilize age in hours and other risk factors to define bilirubin action thresholds, which may be as low as 100 μmol/L for sick premature infants, whereas early discharged babies may only present after bilirubin concentrations are extremely high. Hence, there is a requirement for accurate total bilirubin measurement from <100 to >500 μmol/L, with sufficient precision to assess the rate of bilirubin change with time. Babies presenting with late jaundice always require conjugated bilirubin measurement. It is of concern that many total and direct bilirubin automated kit methods suffer from haemolysis interference, while use of in-house methods or modification of commercial methods has virtually disappeared. External quality assessment has a vital role in providing data on different methods' performance, including accuracy, precision and susceptibility to interference. Laboratories should consider whether their adult bilirubin methods are suitable for neonates.

Heterologous assisted reproduction and kernicterus: the unlucky coincidence reveals an ethical dilemma

Secrecy and anonymity related to heterologous assisted reproduction may hide basic newborn data to neonatologists. Secrecy and anonymity are discussed in view of their possible consequences on relational dynamics and on developmental psychology. Nevertheless, they can also involve the offspring's genetic status regarding inheritable diseases. International guidelines have been recently published on this topic. Because no guidelines are 'ideal' unfortunate and possibly dramatic consequences can occur. We aimed to embark on a debate about this matter starting with a real clinical experience. In our case a rarely fatal but widespread disease, together with the lack of knowledge about parental status led, in a fast succession of clinical events, to the unavoidable insurgence of kernicterus.

Skin bilirubin nomogram for the first 96 h of life in a European normal healthy newborn population, obtained with multiwavelength transcutaneous bilirubinometry

AIM

Hour-specific nomogram evaluation of serum or skin bilirubin is a suitable approach for managing neonatal hyperbilirubinemia and it is recommended by American Academy of Paediatrics. We aimed to provide data about skin bilirubin levels during the natural course of hyperbilirubinemia in European healthy neonates.

METHODS

We enrolled 2198 healthy newborn infants (gestational age [GA]>or= 35 weeks), from 24 to 96 h of life and performed transcutaneous bilirubin (TcB) measurement, in order to draw the nomogram for 10th, 25th, 50th, 75th and 95th percentiles of skin bilirubin, both for term and near term babies. All measurements were performed with a multiwavelength transcutaneous bilirubinometer (Respironics BiliCheck), within 2 h of the designed time and data were analysed with linear and local smoother regression.

RESULTS

We described the peculiar pattern of skin bilirubin increasing rate over different time periods. Bilirubin linearly increases rapidly in the first 48 h and less rapidly from 48 to 72 h, while the increment is insignificant from 72 to 96 h.

CONCLUSION

We provide the first data on skin bilirubin trend in a large predominantly breastfed and healthy European newborn population during the natural course of nonpathologic hyperbilirubinemia. Nomogram and increment rate of skin bilirubin are useful to identify neonates requiring closer evaluation and to plan an adequate follow-up.

Unconjugated bilirubin differentially affects the redox status of neuronal and astroglial cells

We investigated whether nerve cell damage by unconjugated bilirubin (UCB) is mediated by oxidative stress and ascertained the neuronal and astroglial susceptibility to injury. Several oxidative stress biomarkers and cell death were determined following incubation of neurons and astrocytes isolated from rat cortical cerebrum with UCB (0.01-1.0 microM). We show that UCB induces a dose-dependent increase in neuronal death in parallel with the oxidation of cell components and a decrease in the intracellular glutathione content. Comparison of the results obtained in both cell types demonstrates that neurons are more vulnerable than astrocytes to oxidative injury by UCB, for which accounts the lower glutathione stores in neuronal cells. Moreover, neuronal oxidative injury is prevented by supplementation with N-acetylcysteine, a glutathione precursor, whereas astroglial sensitivity to UCB is enhanced by inhibition of glutathione synthesis, using buthionine sulfoximine. Collectively, we demonstrate that oxidative stress is involved in UCB neurotoxicity and depict a new therapeutic approach for UCB-induced oxidative damage.

Glycoursodeoxycholic Acid and Interleukin-10 Modulate the Reactivity of Rat Cortical Astrocytes to Unconjugated Bilirubin

The pathogenesis of bilirubin encephalopathy seems to result from accumulation of unconjugated bilirubin (UCB) within the brain. We have recently demonstrated that UCB causes astroglial release of proinflammatory cytokines and glutamate, as well as cell death. The bile acid glycoursodeoxycholic acid (GUDCA) and the anti-inflammatory cytokine interleukin (IL)-10 have been reported to modulate inflammation and cell survival. In this study we investigated the effect of these therapeutic agents on the astroglial response to UCB. Only GUDCA prevented UCB-induced astroglial death. The secretion of tumor necrosis factor-alpha (TNF-alpha) and IL-1beta elicited by UCB in astrocytes was reduced in the presence of GUDCA and IL-10, whereas the suppression of IL-6 was only counteracted by GUDCA. Neither GUDCA nor IL-10 modulated the accumulation of extracellular glutamate. Additionally, IL-10 markedly inhibited UCB-induced nuclear factor-kappaB nuclear translocation and cytokine mRNA expression, whereas GUDCA only prevented TNF-alpha mRNA expression. Moreover, GUDCA inhibited TNF-alpha- and IL-1beta-converting enzymes, preventing the maturation of these cytokines and their consequent release. Collectively, this study shows that IL-10 action is restricted to UCB-induced release of TNF-alpha and IL-1beta from the astrocytes, whereas GUDCA presents a more ubiquitous action on the astroglial reactivity to UCB. Hence, GUDCA may have potential benefits over an IL-10 therapeutic approach in reducing UCB-induced astrocyte immunostimulation and death.

MAPKs are key players in mediating cytokine release and cell death induced by unconjugated bilirubin in cultured rat cortical astrocytes

When activated by unconjugated bilirubin (UCB), astrocytes are important sources of inflammatory mediators such as TNF-alpha, IL-1beta and IL-6, which may contribute for the neurotoxicity observed during severe neonatal hyperbilirubinemia. In the present study, we have addressed the role of the mitogen-activated protein kinases (MAPKs) p38, Jun N-terminal kinase (JNK)1/2 and extracellular signal-regulated kinase (ERK)1/2 pathways and their relation with the nuclear factor kappaB (NF-kappaB) cascade in the signalling events involved in cytokine release and cell death caused by UCB in primary cultures of rat astrocytes. Stimulation of astrocytes with UCB in the presence of all the MAPK inhibitors prevented UCB-induced release of TNF-alpha and IL-6, while IL-1beta secretion was only reduced by JNK1/2 and ERK1/2 inhibitors. In addition, activation of the NF-kappaB transcription factor, needed for cytokine release by UCB-stimulated astrocytes, was shown to be dependent on JNK1/2 and ERK1/2 phosphorylation. Moreover, all MAPK inhibitors prevented astroglial apoptosis triggered by UCB. Interestingly, UCB-induced lactate dehydrogenase release was prevented by blockade of JNK1/2, ERK1/2 and NF-kappaB cascades but enhanced by p38 inhibition. Taken together, our data demonstrate for the first time that MAPK transduction pathways are key players in the UCB-induced inflammatory response and cell death in astrocytes, probably also involving NF-kappaB modulation. These findings contribute to unraveling the complex mechanisms of astrocyte reactivity to UCB and may ultimately prove useful in the development of new therapeutic strategies to prevent nerve cell damage during acute bilirubin encephalopathy.

Influence of hypoxia and ischemia preconditioning on bilirubin damage to astrocytes

Hypoxia-ischemia in the perinatal period is a common cause of neurologic disability in children and is often associated with neonatal morbidity and mortality. Another frequent condition of the newborn is hyperbilirubinemia and it is well known that deposition of unconjugated bilirubin (UCB) in the central nervous system can damage nerve cells and cause encephalopathy. Interestingly, some studies report the onset of cerebral hypoxia-ischemia as a risk factor for UCB encephalopathy, since that condition often precedes neonatal hyperbilirubinemia. However, the cellular mechanisms triggered by hypoxia-ischemia that may enforce UCB deleterious effects are not well elucidated. Therefore, we designed this study to investigate whether hypoxia (HP) or combined oxygen-glucose deprivation (OGD) followed by reoxygenation, modifies glial cell susceptibility to UCB injury. Thus, cultured astrocytes were exposed to HP or OGD for 4 h and returned to normoxic conditions for another 12 h prior to incubation with UCB for 4 h. HP and OGD effects in UCB toxicity were compared to normoxic conditions. Our results demonstrate that HP and OGD preconditioning increase the vulnerability of glial cells to UCB damage by enhancing some of the deleterious effects of UCB, namely cell death by both apoptosis and necrosis. This preconditioning also augments the UCB-induced stimulation of an inflammatory response by an effect that involves the activation of the nuclear factor kappaB activation. These findings provide a novel basis for the increased risk of brain damage in jaundiced newborns that were previously exposed to hypoxia or ischemia during the perinatal period, namely during delivery.

Quartz crystal microbalance studies on bilirubin adsorption on self-assembled phospholipid bilayers

Bilirubin adsorption on self-assembled phospholipid bilayers was studied using quartz crystal microbalance, and factors influencing its adsorption such as pH, temperature, and solution ionic strength were discussed in detail. The results show the amount of adsorbed bilirubin on self-assembled phospholipid bilayers is small at higher temperature and large at higher pH and solution ionic strength, and the adsorption kinetic parameter estimated from the in situ frequency measurement is (1.8+/-0.27)x10(6) M(-1) (mean +/- S.D.). With the present method, the desorption of adsorbed bilirubin caused by human serum albumin and the photoinduced decomposition of adsorbed bilirubin under light illumination were also examined. QCM measurement provides a useful method for monitoring the adsorption/desorption process of bilirubin on self-assembled phospholipid bilayers.

Biliverdin-induced brainstem auditory evoked potential abnormalities in the jaundiced Gunn rat

Brainstem auditory evoked potential (BAEP) abnormalities occur in jaundiced Gunn rats given sulfadimethoxine to displace bilirubin bound to serum albumin, releasing it into the tissues. One problem with the model is that after displacement, plasma bilirubin levels drop and do not correlate with neurological dysfunction. In this report, we administered biliverdin, the immediate precursor of bilirubin, in 15- to 17-day-old Gunn rat pups to create an improved model of bilirubin-induced neurological dysfunction. Total plasma bilirubin (TB) levels were measured with a Leica bilirubinometer. Biliverdin (40 mg/kg) or phosphate-buffered saline (PBS) was administered either once and BAEPs recorded 8 h later or twice, 12 h apart, and BAEPs recorded 24 h after the initial injection. A single biliverdin injection produced a significantly decreased amplitude of BAEP wave III, 1.21+/-0.25 vs. 0.49+/-0.27 microV (control vs. biliverdin). The two-injection paradigm resulted in a significantly elevated TB (9.9+/-1.2 vs. 14.9+/-3.1 mg/dl; control vs. biliverdin), significant increases in I-II (1.15+/-0.08 vs. 1.42+/-0.09 ms) and I-III (2.17+/-0.08 vs. 2.5+/-0.13 ms) interwave intervals and a decrease in the amplitude of wave III (1.36+/-0.30 vs. 0.38+/-0.26 microV). Additionally, there were significant correlations between TB and the amplitude of wave III (r2=0.74) and TB and the I-III interwave interval (r2=0.51). In summary, biliverdin administration in jaundiced Gunn rat pups produces BAEP abnormalities consistent with those observed in the sulfadimethoxine model and human newborn hyperbilirubinemia and resulted in increased plasma bilirubin levels that correlate with the degree of neurological dysfunction.

Bilirubin-induced immunostimulant effects and toxicity vary with neural cell type and maturation state

Hyperbilirubinemia remains one of the most frequent clinical diagnoses in the neonatal period. The increased vulnerability of premature infants to unconjugated bilirubin (UCB)-induced brain damage may be due to a proneness of immature nerve cells to UCB-toxic stimulus. Thus, in this study, we evaluated UCB-induced cell death, glutamate release and cytokine production, in astrocytes and neurons cultured for different days, in order to relate the differentiation state with cell vulnerability to UCB. The age-dependent activation of the nuclear factor-kappaB (NF-kappaB), an important transcription factor involved in inflammation, was also investigated. Furthermore, responsiveness of neurons and astrocytes to UCB were compared in order to identify the most susceptible to each induced effect, as an approach to what happens in vivo. The results clearly showed that immature nerve cells are more vulnerable than the most differentiated ones to UCB-induced cell death, glutamate release and tumour necrosis factor (TNF)-alpha secretion. Moreover, astrocytes seem to be more competent cells in releasing glutamate and in producing an inflammatory response when injured by UCB. Activation of NF-kappaB by UCB also presents a cell-age-dependent pattern, and values vary with neural cell type. Again, astrocytes have the highest activation levels, which are correlated with the greater amount of cytokine production observed in these cells. These results contribute to a better knowledge of the mechanisms leading to UCB encephalopathy by elucidation of age- and type-related differences in neural cell responses to UCB.

Inflammatory signalling pathways involved in astroglial activation by unconjugated bilirubin

During neonatal hyperbilirubinaemia, astrocytes activated by unconjugated bilirubin (UCB) may contribute to brain toxicity through the production of cytokines. As a first step in addressing the signal transduction cascades involved in the UCB-induced astroglial immunological response, we tested whether tumour necrosis factor (TNF)-alpha receptor 1 (TNFR1), mitogen-activated protein kinase (MAPK) and nuclear factor kappaB (NF-kappaB) would be activated in astrocytes exposed to UCB, and examined the profile of cytokine production. Astrocyte cultures stimulated with UCB showed a rapid rise in TNFR1 protein levels, followed by activation of the MAPKs p38, Jun N-terminal kinase1/2 and extracellular signal-regulated kinase1/2, and NF-kappaB. Interestingly, the induction of these signal effectors preceded the early up-regulation of TNF-alpha and interleukin (IL)-1beta mRNAs, and later secretion of TNF-alpha, IL-1beta and IL-6. Treatment of astrocytes with UCB also induced cell death, with levels comparable to those obtained after exposure of astrocytes to recombinant TNF-alpha and IL-1beta. Moreover, loss of cell viability and cytokine secretion were reduced when the NF-kappaB signal transduction pathway was inhibited, suggesting a key role for NF-kappaB in the astroglial response to UCB. These results demonstrate the complexity of the molecular mechanisms involved in cell injury by UCB during hyperbilirubinaemia and provide a basis for the development of novel therapeutic strategies.

Muscular dystonia and athetosis in six patients with congenital nephrotic syndrome of the Finnish type (NPHS1)

Congenital nephrotic syndrome of the Finnish type (NPHS1, CNF) is an autosomal recessively inherited disease occurring due to mutations in the nephrin gene (NPHS1). Two main Finnish mutations exist: Fin-major and minor, which both cause a lack of nephrin and absence of the slit diaphragm between the podocytes. This leads to severe proteinuria, nephrotic syndrome and infections, and without dialysis or renal transplantation, death in infancy. Between 1984 and 2003, six (8.6%) of the 70 NPHS1 patients diagnosed at our institution had, in addition to their renal disease, similar neurological symptoms. All six showed a severe dyskinetic cerebral palsy-like syndrome with dystonic features, athetosis and a hearing defect. The neurological symptoms became apparent during their 1st year of life and were diagnosed before 11 months of age. MRI showed increased signal intensity in T2-weighted images in the globus pallidus area. No mitochondrial gene mutations explaining the neurological symptoms were found, nor did external neurological complications explain them when compared with 29 NPHS1 control patients. Four children died at an early age: two during dialysis and two shortly after renal transplantation. Two are still alive with a functioning graft. Both have severe motor defects, but are mentally active and social.