Genetic and functional correction of argininosuccinate lyase deficiency using CRISPR adenine base editors

Argininosuccinate lyase deficiency (ASLD) is a recessive metabolic disorder caused by variants in ASL. In an essential step in urea synthesis, ASL breaks down argininosuccinate (ASA), a pathognomonic ASLD biomarker. The severe disease forms lead to hyperammonemia, neurological injury, and even early death. The current treatments are unsatisfactory, involving a strict low-protein diet, arginine supplementation, nitrogen scavenging, and in some cases, liver transplantation. An unmet need exists for improved, efficient therapies. Here, we show the potential of a lipid nanoparticle-mediated CRISPR approach using adenine base editors (ABEs) for ASLD treatment. To model ASLD, we first generated human-induced pluripotent stem cells (hiPSCs) from biopsies of individuals homozygous for the Finnish founder variant (c.1153C>T [p.Arg385Cys]) and edited this variant using the ABE. We then differentiated the hiPSCs into hepatocyte-like cells that showed a 1,000-fold decrease in ASA levels compared to those of isogenic non-edited cells. Lastly, we tested three different FDA-approved lipid nanoparticle formulations to deliver the ABE-encoding RNA and the sgRNA targeting the ASL variant. This approach efficiently edited the ASL variant in fibroblasts with no apparent cell toxicity and minimal off-target effects. Further, the treatment resulted in a significant decrease in ASA, to levels of healthy donors, indicating restoration of the urea cycle. Our work describes a highly efficient approach to editing the disease-causing ASL variant and restoring the function of the urea cycle. This method relies on RNA delivered by lipid nanoparticles, which is compatible with clinical applications, improves its safety profile, and allows for scalable production.

European expert recommendations on clinical investigation and evaluation of high-risk medical devices for children

Several high-risk medical devices for children have become unavailable in the European Union (EU), since requirements and costs for device certification increased markedly due to the EU Medical Device Regulation. The EU-funded CORE-MD project held a workshop in January 2023 with experts from various child health specialties, representatives of European paediatric associations, a regulatory authority and the European Commission Directorate General Health and Food Safety. A virtual follow-up meeting took place in March 2023. We developed recommendations for investigation of high-risk medical devices for children building on participants' expertise and results of a scoping review of clinical trials on high-risk medical devices in children. Approaches for evaluating and certifying high-risk medical devices for market introduction are proposed.

Availability and use of rapid diagnostic tests for the management of acute childhood infections in Europe: A cross-sectional survey of paediatricians

BACKGROUND

Point-of-care-tests (POCTs) have been advocated to optimise care in patients with infections but their actual use varies. This study aimed to estimate the variability in the adoption of current POCTs by paediatricians across Europe, and to explore the determinants of variability.

METHODS AND FINDINGS

A cross-sectional survey was conducted of hospital and primary care paediatricians, recruited through professional networks. Questions focused on the availability and use of currently available POCTs. Data were analysed descriptively and using Median Odds Ratio (MOR) to measure variation between countries. Multilevel regression modelling using changes in the area under the receiver operating characteristic curve of models were used to assess the contribution of individual or workplace versus country level factors, to the observed variation. The commonest POCT was urine dipsticks (UD) which were available to >80% of primary care and hospital paediatricians in 68% (13/19) and 79% (23/29) countries, respectively. Availability of all POCTs varied between countries. In primary care, the country (MOR) varied from 1.61 (95%CI: 1.04-2.58) for lactate to 7.28 (95%CI: 3.04-24.35) for UD. In hospitals, the country MOR varied from 1.37 (95%CI:1.04-1.80) for lactate to 11.93 (95%CI:3.35-72.23) for UD. Most paediatricians in primary care (69%, 795/1154) and hospital (81%, 962/1188) would use a diagnostic test in the case scenario of an infant with undifferentiated fever. Multilevel regression modelling showed that the country of work was more important in predicting both the availability and use of POCTs than individual or workplace characteristics.

CONCLUSION

There is substantial variability in the adoption of POCTs for the management of acute infections in children across Europe. To inform future implementation of both existing and innovative tests, further research is needed to understand what drives the variation between countries, the needs of frontline clinicians, and the role of diagnostic tests in the management of acute childhood infections.

The Finnish genetic heritage in 2022 – from diagnosis to translational research

Isolated populations have been valuable for the discovery of rare monogenic diseases and their causative genetic variants. Finnish disease heritage (FDH) is an example of a group of hereditary monogenic disorders caused by single major, usually autosomal-recessive, variants enriched in the population due to several past genetic drift events. Interestingly, distinct subpopulations have remained in Finland and have maintained their unique genetic repertoire. Thus, FDH diseases have persisted, facilitating vigorous research on the underlying molecular mechanisms and development of treatment options. This Review summarizes the current status of FDH, including the most recently discovered FDH disorders, and introduces a set of other recently identified diseases that share common features with the traditional FDH diseases. The Review also discusses a new era for population-based studies, which combine various forms of big data to identify novel genotype–phenotype associations behind more complex conditions, as exemplified here by the FinnGen project. In addition to the pathogenic variants with an unequivocal causative role in the disease phenotype, several risk alleles that correlate with certain phenotypic features have been identified among the Finns, further emphasizing the broad value of studying genetically isolated populations.

CRISPR correction of the Finnish ornithine delta-aminotransferase mutation restores metabolic homeostasis in iPSC from patients with gyrate atrophy

Hyperornithinemia with gyrate atrophy of the choroid and retina (HOGA) is a severe recessive inherited disease, causing muscular degeneration and retinochoroidal atrophy that progresses to blindness. HOGA arises from mutations in the ornithine aminotransferase (OAT) gene, and nearly one-third of the known patients worldwide are homozygous for the Finnish founder mutation OAT c.1205 T > C p.(Leu402Pro). We have corrected this loss-of-function OAT mutation in patient-derived induced pluripotent stem cells (iPSCs) using CRISPR/Cas9. The correction restored OAT expression in stem cells and normalized the elevated ornithine levels in cell lysates and cell media. These results show an efficient recovery of OAT function in iPSC, encouraging the possibility of autologous cell therapy for the HOGA disease.

Expert guidance on the multidisciplinary management of cystinosis in adolescent and adult patients

Cystinosis, a rare autosomal recessive lysosomal storage disorder, results in an abnormal accumulation of the amino acid cystine in multiple organs and tissues of the body. Renal symptoms typically develop in the first few months of life, with extra-renal manifestations becoming apparent over the next 10–20 years, which require coordinated multidisciplinary care. Here, we describe a consensus-based guidance to support the management of adolescents and adults living with cystinosis. The programme was led by a Steering Committee (SC) of six experts in the management of patients with cystinosis, who identified a list of 15 key questions reflecting the multi-organ effects of cystinosis. An Extended Faculty (EF) of eight additional specialists was invited to answer the questions via an online digital platform using a quasi-Delphi approach. The consolidated answers were summarized into recommendations. Where evidence was lacking, recommendations were developed using collective expert consensus. The EF was asked to agree/disagree with the clinical recommendations. The expert-agreed clinical recommendations provide guidance that considers both renal and extra-renal systems. The topics covered are advice on fertility and family planning, consideration of the nervous, muscular, ophthalmic, cardio-respiratory, endocrine, dermatological and gastrointestinal systems, as well as guidance on dental care, diet, lifestyle, and improving quality of life and psychological well-being. In summary, this work outlines recommendations and a checklist for clinicians with a vision for improving and standardizing the multidisciplinary care for patients with cystinosis.

An eHealth Framework for Managing Pediatric Growth Disorders and Growth Hormone Therapy

Background

The use of technology to support health and health care has grown rapidly in the last decade across all ages and medical specialties. Newly developed eHealth tools are being implemented in long-term management of growth failure in children, a low prevalence pediatric endocrine disorder.

Objective

Our objective was to create a framework that can guide future implementation and research on the use of eHealth tools to support patients with growth disorders who require growth hormone therapy.

Methods

A total of 12 pediatric endocrinologists with experience in eHealth, from a wide geographical distribution, participated in a series of online discussions. We summarized the discussions of 3 workshops, conducted during 2020, on the use of eHealth in the management of growth disorders, which were structured to provide insights on existing challenges, opportunities, and solutions for the implementation of eHealth tools across the patient journey, from referral to the end of pediatric therapy.

Results

A total of 815 responses were collected from 2 questionnaire-based activities covering referral and diagnosis of growth disorders, and subsequent growth hormone therapy stages of the patient pathway, relating to physicians, nurses, and patients, parents, or caregivers. We mapped the feedback from those discussions into a framework that we developed as a guide to integration of eHealth tools across the patient journey. Responses focused on improved clinical management, such as growth monitoring and automation of referral for early detection of growth disorders, which could trigger rapid evaluation and diagnosis. Patient support included the use of eHealth for enhanced patient and caregiver communication, better access to educational opportunities, and enhanced medical and psychological support during growth hormone therapy management. Given the potential availability of patient data from connected devices, artificial intelligence can be used to predict adherence and personalize patient support. Providing evidence to demonstrate the value and utility of eHealth tools will ensure that these tools are widely accepted, trusted, and used in clinical practice, but implementation issues (eg, adaptation to specific clinical settings) must be addressed.

Conclusions

The use of eHealth in growth hormone therapy has major potential to improve the management of growth disorders along the patient journey. Combining objective clinical information and patient adherence data is vital in supporting decision-making and the development of new eHealth tools. Involvement of clinicians and patients in the process of integrating such technologies into clinical practice is essential for implementation and developing evidence that eHealth tools can provide value across the patient pathway.

Connected health for growth hormone treatment research and clinical practice: learnings from different sources of real-world evidence (RWE)-large electronically collected datasets, surveillance studies and individual patients' cases

Background

A range of factors can reduce the effectiveness of treatment prescribed for the long-term management of chronic health conditions, such as growth disorders. In particular, prescription medications may not achieve the positive outcomes expected because approximately half of patients adhere poorly to the prescribed treatment regimen.

Methods

Adherence to treatment has previously been assessed using relatively unreliable subjective methods, such as patient self-reporting during clinical follow-up, or counting prescriptions filled or vials returned by patients. Here, we report on a new approach, the use of electronically recorded objective evidence of date, time, and dose taken which was obtained through a comprehensive eHealth ecosystem, based around the easypod™ electromechanical auto-injection device and web-based connect software. The benefits of this eHealth approach are also illustrated here by two case studies, selected from the Finnish cohort of the easypod™ Connect Observational Study (ECOS), a 5-year, open-label, observational study that enrolled children from 24 countries who were being treated with growth hormone (GH) via the auto-injection device.

Results

Analyses of data from 9314 records from the easypod™ connect database showed that, at each time point studied, a significantly greater proportion of female patients had high adherence (≥ 85%) than male patients (2849/3867 [74%] vs 3879/5447 [71%]; P < 0.001). Furthermore, more of the younger patients (< 10 years for girls, < 12 years for boys) were in the high adherence range (P < 0.001). However, recursive partitioning of data from ECOS identified subgroups with lower adherence to GH treatment ‒ children who performed the majority of injections themselves at an early age (~ 8 years) and teenagers starting treatment aged ≥ 14 years.

Conclusions

The data and case studies presented herein illustrate the importance of adherence to GH therapy and how good growth outcomes can be achieved by following treatment as described. They also show how the device, software, and database ecosystem can complement normal clinical follow-up by providing HCPs with reliable information about patient adherence between visits and also providing researchers with real-world evidence of adherence and growth outcomes across a large population of patients with growth disorders treated with GH via the easypod™ device.

Motivational Interviewing and Glycemic Control in Adolescents With Poorly Controlled Type 1 Diabetes: A Randomized Controlled Pilot Trial

A multicenter randomized controlled pilot trial investigated whether motivational interviewing (MI) by diabetes physicians improves glycemic control and variability in the context of follow-up for adolescent patients with poorly controlled type 1 diabetes. Patients (n = 47) aged 12 to 15.9 years who showed poor glycemic control (HbA1c >75 mmol/mol/9.0%) were randomized to standard education (SE) only or MI+SE, with study physicians randomized to employ MI+SE (N = 24 patients) or SE only (N = 23). For one year of follow-up, the main outcome measurements were obtained at three-month visits (HbA1c) or six-monthly: time in range (TIR) and glycemic variability (CV). Mean adjusted 12-month change in HbA1c was similar between the MI+SE and SE-only group (-3.6 vs. -1.0 mmol/mol), and no inter-group differences were visible in the mean adjusted 12-month change in TIR (-0.8 vs. 2.6%; P = 0.53) or CV (-0.5 vs. -6.2; P = 0.26). However, the order of entering the study correlated significantly with the 12-month change in HbA1c in the MI+SE group (r = -0.5; P = 0.006) and not in the SE-only group (r = 0.2; P = 0.4). No link was evident between MI and changes in quality of life. The authors conclude that MI's short-term use by diabetes physicians managing adolescents with poorly controlled type 1 diabetes was not superior to SE alone; however, improved skills in applying the MI method at the outpatient clinic may produce greater benefits in glycemic control.

Adrenal function after induction therapy for acute lymphoblastic leukemia in children short: adrenal function in ALL

Prednisolone used in the induction phase of the treatment of acute lymphoblastic leukemia (ALL) may suppress hypothalamic-pituitary-adrenal axis and require hydrocortisone substitution. In this retrospective analysis, we reviewed altogether 371 ACTH stimulation tests of 352 children after a uniform NOPHO (Nordic Society of Pediatric Hematology and Oncology) ALL induction. Both low- and standard-dose ACTH tests were used. Full recovery of adrenal function was defined by both normal basal and stimulated cortisol levels. Sixty-two percent of patients were detected with normal adrenal function in median of 15 days after tapering of prednisolone. Both low basal and stimulated cortisol levels were detected in 13% of patients. The median time to normal adrenal function was 31 days (95% CI 28-34), 24 days (95% CI 18-30), and 12 days (95% CI 10-14) for those with basal cortisol <107, 107-183, and >183 nmol/L at first ACTH testing, respectively. Patients with fluconazole prophylaxis had higher median baseline cortisol levels compared to patients without prophylaxis (207 nmol/L, range 21-839 nmol/L vs. 153 nmol/L, range 22-832 nmol/L, P = 0.003).Conclusion: These data can be used to reduce unnecessary substitution or testing, but also to guarantee hydrocortisone substitution for those at risk. What is Known: •These data can be used to reduce unnecessary hydrocortisone substitution or ACTH testing. •Our data helps to guarantee hydrocortisone substitution for those at risk of adrenal insufficiency. What is New: •Full recovery of adrenal function after ALL induction is detected in 62% of patients already at 15 days after tapering of prednisolone. •Both basal and stimulated cortisol testing are required for detection of full adrenal recovery. •Recovery time of adrenal function is extended over 3-4 weeks after tapering of prednisolone in patients with low basal cortisol levels (<107 nmol/L) at first testing.

Clinical, biochemical, and molecular overview of transaldolase deficiency and evaluation of the endocrine function: Update of 34 patients

BACKGROUND

Transaldolase deficiency (TALDO-D) is a rare autosomal recessive inborn error of the pentose phosphate pathway. Since its first description in 2001, several case reports have been published, but there has been no comprehensive overview of phenotype, genotype, and phenotype-genotype correlation.

METHODS

We performed a retrospective questionnaire and literature study of clinical, biochemical, and molecular data of 34 patients from 25 families with proven TALDO-D. In some patients, endocrine abnormalities have been found. To further evaluate these abnormalities, we performed biochemical investigations on blood of 14 patients.

RESULTS AND CONCLUSIONS

Most patients (n = 22) had an early-onset presentation (prenatally or before 1 month of age); 12 patients had a late-onset presentation (3 months to 9 years). Main presenting symptoms were intrauterine growth restriction, dysmorphic facial features, congenital heart disease, anemia, thrombocytopenia, and hepato(spleno)megaly. An older sib of two affected patients was asymptomatic until the age of 9 years, and only after molecular diagnosis was hepatomegaly noted. In some patients, there was gonadal dysfunction with low levels of testosterone and secondary luteinizing hormone (LH) and follicle-stimulating hormone (FSH) abnormalities later in life. This overview provides information that can be helpful for managing patients and counseling families regarding prognosis. Diagnostic guidelines, possible genotype-phenotype correlations, treatment options, and pathophysiological disease mechanisms are proposed.

Earlier diagnosis and strict diets improve the survival rate and clinical course of long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency

AIM

Long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD) is a severe metabolic disease that, without treatment, often leads to premature death or serious handicap. The aim of this study was to evaluate the clinical course of LCHADD with the homozygous 1528G>C (E510Q) mutation when patients underwent strict dietary treatment.

METHODS

From 1997 to 2010, 16 patients with LCHADD were diagnosed in Finland. They were followed up, and data were prospectively collected as they emerged. Clinical data before diagnosis were retrospectively collected from hospital records. This cohort was compared with an earlier cohort of patients diagnosed from 1976 to 1996.

RESULTS

The disease presented from birth to five months of age with failure to thrive, hypotonia, hepatomegaly, metabolic acidosis, cardiomyopathy and hypoketotic hypoglycaemia. In this cohort, the therapeutic delay was 0-30 days and the survival rate at the end of the study was 62.5% compared with 10-year survival rate of 14.3% for the earlier cohort. The survivors were in good overall condition, but some of them had developed mild retinopathy or mild neuropathy.

CONCLUSION

Earlier diagnosis and stricter dietary regimes improved the survival rates and clinical course of patients with LCHADD in Finland. However, improvements in therapy are still needed to prevent the development of long-term complications, such as retinopathy and neuropathy.

Peripheral neuropathy in patients with long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency - A follow-up EMG study of 12 patients

BACKGROUND

The neonatal screening and early start of the dietary therapy have improved the outcome of long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD). The acute symptoms of LCHADD are hypoketotic hypoglycemia, failure to thrive, hepatopathy and rhabdomyolysis. Long term complications are retinopathy and neuropathy. Speculated etiology of these long term complications are the accumulation and toxicity of hydroxylacylcarnitines and long-chain fatty acid metabolites or deficiency of essential fatty acids.

AIMS

To study the possible development of polyneuropathy in LCHADD patients with current dietary regimen.

METHODS

Development of polyneuropathy in 12 LCHADD patients with the homozygous common mutation c.G1528C was evaluated with electroneurography (ENG) studies. The ENG was done 1-12 times to each patient, between the ages of 3 and 40 years. Clinical data of the patients were collected from the patient records.

RESULTS

The first sign of polyneuropathy was detected between the ages of 6-12 years, the first abnormality being reduction of the sensory amplitudes of the sural nerves. With time, progression was detected by abnormalities in sensory responses extending to upper limbs, as well as abnormalities in motor responses in lower limbs. Altogether, eight of the patients had polyneuropathy, despite good compliancy of the diet.

CONCLUSIONS

This study is the first to report the evolution of polyneuropathy with clinical neurophysiological methods in a relative large LCHADD patient group. Despite early start, and good compliance of the therapy, 6/10 of the younger patients developed neuropathy. However, in most patients the polyneuropathy was less severe than previously described.

LMNA Mutation c.917T>G (p.L306R) Leads to Deleterious Hyper-Assembly of Lamin A/C and Associates with Severe Right Ventricular Cardiomyopathy and Premature Aging

Mutations in the LMNA gene coding for the nuclear lamina proteins lamin A and its smaller splice form lamin C associate with a heterogeneous group of diseases collectively called laminopathies. Here, we describe a 2-year-old patient with a previously undescribed phenotype including right ventricular cardiomyopathy, progeroid features, and premature death. Sequencing of LMNA revealed a novel heterozygous de novo mutation p.L306R located in the α-helical rod domain of A-type lamins. Fibroblasts from the patient showed reduced proliferation and early premature replicative senescence, as characterized by progressive hyperlobulation of the nuclei, abnormally clustered centromeres, loss of lamin B1, and reorganization of promyelocytic leukemia nuclear bodies. Furthermore, the patient cells were more sensitive to double-strand DNA breaks. Similar structural and phenotypic defects were observed in normal fibroblasts transfected with FLAG-tagged p.L306R lamin A. Correspondingly, in vitro assembly studies revealed that the p.L306R generates a "hyper-assembly" mutant of lamin A that forms extensive fiber arrays under physiological conditions where wild-type lamin A is still largely soluble. In summary, we report a novel LMNA p.L306R mutation that leads to previously undescribed hyper-assembly of lamin A, heavy distortion of nuclear shape and that manifests as right ventricular cardiomyopathy and premature aging.

Patients with organic acidaemias have an altered thiol status

AIM

To study whether patients with organic acidaemias have altered glutathione (GSH) levels and thiol redox status. Previously, organic acidaemias have been associated with mitochondrial dysfunction and oxidative stress, suggesting an increased need for antioxidant protection. Furthermore, dietary protein restriction may impair GSH synthesis in these diseases.

METHODS

In children with organic acidaemias, cysteine (CYSH) and GSH concentrations in plasma and erythrocytes as well as erythrocyte GSH peroxidase, GSH reductase, GSH S-transferase and glucose-6-phosphate dehydrogenase activities were studied. In addition, GSH and CYSH concentrations were measured in human fibroblasts exposed to organic acids.

RESULTS

Patients with organic acidaemias had lower plasma GSH concentration than their controls. A greater fraction of GSH and CYSH in the patients' plasma was oxidized, suggesting decreased GSH synthesis and increased consumption.

CONCLUSION

Patients with organic acidaemias may have a relative GSH deficiency. With further research, these results could also have therapeutic implications.

Plasma thiol status is altered in children with mitochondrial diseases

OBJECTIVE

This study was undertaken to investigate thiol metabolism as a marker of oxidative stress and antioxidative defence capacity in a cohort of children with biochemically and/or genetically confirmed mitochondrial disease. Previous studies suggest that lower glutathione levels, which have been shown to further compromise mitochondrial function, may occur in these diseases. Better understanding of the pathogenesis of mitochondrial diseases is important in order to improve their treatment.

METHODS

We studied plasma and erythrocyte glutathione and cysteine levels, the activities of erythrocyte glutathione peroxidase (GPx), glutathione reductase (GR), glucose 6-phosphate dehydrogenase G6PDH) and glutathione S-transferase (GST), as well as the levels of erythrocyte thiobarbituric acid-reactive species (TBA-RS) and protein carbonyls in 10 children with a biochemical and/or genetic diagnosis of mitochondrial disease and six controls.

RESULTS

Levels of reduced cysteine (CYSH) as well as reduced to oxidised cysteine ratio were lower in plasma of patients with mitochondrial diseases (p = 0.008 and p = 0.02, respectively). Plasma levels of reduced glutathione (GSH) were low in patients with mitochondrial diseases, mostly below the detection limit. We did not detect significant differences in erythrocyte thiols or glutathione-related enzyme activities.

CONCLUSION

Plasma thiols and their redox state are altered in patients with mitochondrial diseases, suggesting an increase in oxidative stress and depletion of antioxidant supplies. If confirmed in further studies, this relative thiol deficiency could be an important factor in the pathophysiology of mitochondrial diseases.

GnRH-deficient phenotypes in humans and mice with heterozygous variants in KISS1/Kiss1

CONTEXT

KISS1 is a candidate gene for GnRH deficiency.

OBJECTIVE

Our objective was to identify deleterious mutations in KISS1.

PATIENTS AND METHODS

DNA sequencing and assessment of the effects of rare sequence variants (RSV) were conducted in 1025 probands with GnRH-deficient conditions.

RESULTS

Fifteen probands harbored 10 heterozygous RSV in KISS1 seen in less than 1% of control subjects. Of the variants that reside within the mature kisspeptin peptide, p.F117L (but not p.S77I, p.Q82K, p.H90D, or p.P110T) reduces inositol phosphate generation. Of the variants that lie within the coding region but outside the mature peptide, p.G35S and p.C53R (but not p.A129V) are predicted in silico to be deleterious. Of the variants that lie outside the coding region, one (g.1-3659C→T) impairs transcription in vitro, and another (c.1-7C→T) lies within the consensus Kozak sequence. Of five probands tested, four had abnormal baseline LH pulse patterns. In mice, testosterone decreases with heterozygous loss of Kiss1 and Kiss1r alleles (wild-type, 274 ± 99, to double heterozygotes, 69 ± 16 ng/dl; r(2) = 0.13; P = 0.03). Kiss1/Kiss1r double-heterozygote males have shorter anogenital distances (13.0 ± 0.2 vs. 15.6 ± 0.2 mm at P34, P < 0.001), females have longer estrous cycles (7.4 ± 0.2 vs. 5.6 ± 0.2 d, P < 0.01), and mating pairs have decreased litter frequency (0.59 ± 0.09 vs. 0.71 ± 0.06 litters/month, P < 0.04) and size (3.5 ± 0.2 vs. 5.4 ± 0.3 pups/litter, P < 0.001) compared with wild-type mice.

CONCLUSIONS

Deleterious, heterozygous RSV in KISS1 exist at a low frequency in GnRH-deficient patients as well as in the general population in presumably normal individuals. As in Kiss1(+/-)/Kiss1r(+/-) mice, heterozygous KISS1 variants in humans may work with other genetic and/or environmental factors to cause abnormal reproductive function.

Growth hormone therapy is safe and effective in patients with lysinuric protein intolerance

BACKGROUND

Lysinuric protein intolerance (LPI) is an autosomal recessive cationic amino acid transport defect characterized by episodes of postprandial hyperammonemias and spontaneous protein aversion. Subnormal growth is common in spite of appropriate nutritional therapy. Growth hormone (GH) therapy promotes appetite, protein synthesis and accretion, but its possible growth-promoting effects and safety in patients with LPI are poorly known.

METHODS

Four LPI children aged 7-16 years were treated with GH for a period of 3-4.5 years. Dietary intakes and plasma amino acid levels were analyzed frequently in addition to routine monitoring of GH therapy.

RESULTS

Insulin-like growth factor-1 concentration was low and bone age was delayed in all LPI patients, but GH provocative test was pathological in only one of the patients. During the 3-4.5 years of GH therapy (dose 0.035-0.050 mg/kg/day), bone age did not catch up but height standard deviation score (SDS) improved by 0.7-1.8 SDS. There were no episodes of hyperammonemias.

CONCLUSIONS

Our data support safety and growth-promoting potential of long-term GH therapy in patients with LPI.

Change in plasma and erythrocyte thiol levels in children undergoing fasting studies for investigation of hypoglycaemia

INTRODUCTION

It is unclear how repeated episodes of HG cause brain injury, but oxidative stress has been suggested to play a role. Non-protein thiols (glutathione, GSH, and cysteine, CYSH) form an important antioxidant defence, and their redox state is dependent on intracellular energy supplies and reducing power which are possibly compromised during low blood glucose concentrations.

AIM OF STUDY

To study thiol status in children undergoing investigations for hypoglycaemia . We hypothesised that thiol metabolism, dependent on intracellular energy supplies and reducing power, might deteriorate during hypoglycaemic episodes.

MATERIAL AND METHODS

Seventeen children with suspected hypoglycaemic episodes underwent a diagnostic fast. We measured plasma and erythrocyte GSH and CYSH as well as activities of enzymes related to glutathione metabolism during and after the fast.

RESULTS

A positive correlation between plasma glucose and reduced (free) cysteine was observed, but plasma GSH levels did not change significantly. Hypoglycaemia was associated with a rise in erythrocyte total cysteine without changes in erythrocyte GSH.

CONCLUSION

Low blood glucose concentration is associated with changes in thiol status, which compromise the protection against oxidative stress. This further supports the hypothesis of oxidative stress being associated with hypoglycaemia.

Cow's milk allergy is associated with changes in urinary organic acid concentrations

Cow's milk allergy (CMA) is the most common form of food allergy affecting 2.5% of children, but the diagnosis is often difficult. Both intestinal microbiota and barrier function seem to be disturbed in patients with food allergies, and administration of probiotics has been shown to normalize intestinal microbiota and alleviate symptoms. We hypothesized that the differences in intestinal metabolic activity and permeability could lead to detectable changes in the end-products of metabolism in patients with CMA. This could offer new diagnostic possibilities. The urinary concentrations of 37 organic acids were studied by a mass spectrometry-based method in 35 infants aged under 1 yr with atopic eczema, 16 of them having CMA diagnosed with a double-blind placebo-controlled food challenge test. The control group consisted of the remaining 19 infants with only atopic eczema. In a second study, Lactobacillus rhamnosus GG (LGG) or placebo was administered to the infants with CMA for 4 wk and the urinary organic acids were analysed again. CMA patients and patients with only atopic eczema had statistically significant differences in urinary concentrations of hydroxybutyrate (p<0.001); adipate and isocitrate (p<0.01 for both); homovanillate, suberate, tartarate, 3-indoleacetate and 5-hydroxyindoleacetate (p<0.05 for all). These concentrations did not change significantly following LGG administration to the CMA patients, but a trend towards the control group was seen. Thus, CMA is associated with changes in some urinary organic acid levels. These differences between atopic infants with and without CMA could be investigated as a novel approach for CMA diagnosis.

Metabolomics in angiotensin II-induced cardiac hypertrophy

Angiotensin II (Ang II) induces mitochondrial dysfunction. We tested whether Ang II alters the "metabolomic" profile. We harvested hearts from 8-week-old double transgenic rats harboring human renin and angiotensinogen genes (dTGRs) and controls (Sprague-Dawley), all with or without Ang II type 1 receptor (valsartan) blockade. We used gas chromatography coupled with time-of-flight mass spectrometry to detect 247 intermediary metabolites. We used a partial least-squares discriminate analysis and identified 112 metabolites that differed significantly after corrections (false discovery rate q <0.05). We found great differences in the use of fatty acids as an energy source, namely, decreased levels of octanoic, oleic, and linoleic acids in dTGR (all P<0.01). The increase in cardiac hypoxanthine levels in dTGRs suggested an increase in purine degradation, whereas other changes supported an increased ketogenic amino acid tyrosine level, causing energy production failure. The metabolomic profile of valsartan-treated dTGRs more closely resembled Sprague-Dawley rats than untreated dTGRs. Mitochondrial respiratory chain activity of cytochrome C oxidase was decreased in dTGRs, whereas complex I and complex II were unaltered. Mitochondria from dTGR hearts showed morphological alterations suggesting increased mitochondrial fusion. Cardiac expression of the redox-sensitive and the cardioprotective metabolic sensor sirtuin 1 was increased in dTGRs. Interestingly, valsartan changed the level of 33 metabolites and induced mitochondrial biogenesis in Sprague-Dawley rats. Thus, distinct patterns of cardiac substrate use in Ang II-induced cardiac hypertrophy are associated with mitochondrial dysfunction. The finding underscores the importance of Ang II in the regulation of mitochondrial biogenesis and cardiac metabolomics, even in healthy hearts.

Kiss1-/- mice exhibit more variable hypogonadism than Gpr54-/- mice

The G protein-coupled receptor Gpr54 and its ligand metastin (derived from the Kiss1 gene product kisspeptin) are key gatekeepers of sexual maturation. Gpr54 knockout mice demonstrate hypogonadotropic hypogonadism, but until recently, the phenotype of Kiss1 knockout mice was unknown. This report describes the reproductive phenotypes of mice carrying targeted deletions of Kiss1 or Gpr54 on the same genetic background. Both Kiss1 and Gpr54 knockout mice are viable but infertile and have abnormal sexual maturation; the majority of males lack preputial separation, and females have delayed vaginal opening and absence of estrous cycling. Kiss1 and Gpr54 knockout males have significantly smaller testes compared with controls. Gpr54 knockout females have smaller ovaries and uteri than wild-type females. However, Kiss1 knockout females demonstrate two distinct phenotypes: half have markedly reduced gonadal weights similar to those of Gpr54 knockout mice, whereas half exhibit persistent vaginal cornification and have gonadal weights comparable with those of wild-type females. FSH levels in both Kiss1 and Gpr54 knockout males and females are significantly lower than in controls. When injected with mouse metastin 43-52, a Gpr54 agonist, Gpr54 knockout mice fail to increase gonadotropins, whereas Kiss1 knockout mice respond with increased gonadotropin levels. In summary, both Kiss1 and Gpr54 knockout mice have abnormal sexual maturation consistent with hypogonadotropic hypogonadism, although Kiss1 knockout mice appear to be less severely affected than their receptor counterparts. Kiss1 knockout females demonstrate a bimodal phenotypic variability, with some animals having higher gonadal weight, larger vaginal opening, and persistent vaginal cornification.

N-acetylcysteine reduces lipopolysaccharide-sensitized hypoxic-ischemic brain injury

OBJECTIVE

Maternal inflammation/infection alone or in combination with birth asphyxia increases the risk for perinatal brain injury. Free radicals are implicated as major mediators of inflammation and hypoxia-ischemia (HI)-induced perinatal brain injury. This study evaluated the neuroprotective efficacy of a scavenging agent, N-acetylcysteine (NAC), in a clinically relevant model.

METHODS

Lipopolysaccharide (LPS)-sensitized HI brain injury was induced in 8-day-old neonatal rats. NAC was administered in multiple doses, and brain injury was evaluated at 7 days after HI.

RESULTS

NAC (200mg/kg) provided marked neuroprotection with up to 78% reduction of brain injury in the pre+post-HI treatment group and 41% in the early (0 hour) post-HI treatment group, which was much more pronounced protection than another free radical scavenger, melatonin. Protection by NAC was associated with the following factors: (1) reduced isoprostane activation and nitrotyrosine formation; (2) increased levels of the antioxidants glutathione, thioredoxin-2, and (3) inhibition of caspase-3, calpain, and caspase-1 activation.

INTERPRETATION

NAC provides substantial neuroprotection against brain injury in a model that combines infection/inflammation and HI. Protection by NAC was associated with improvement of the redox state and inhibition of apoptosis, suggesting that these events play critical roles in the development of lipopolysaccharide-sensitized HI brain injury.

Melatonin reduces inflammation and cell death in white matter in the mid-gestation fetal sheep following umbilical cord occlusion

The premature infant is at increased risk of cerebral white matter injury. Melatonin is neuroprotective in adult models of focal cerebral ischemia and attenuates ibotenate-induced white matter cysts in neonatal mice. Clinically, melatonin has been used to treat sleep disorders in children without major side effects. The aim of this study was to investigate the protective and anti-inflammatory effects of melatonin in the immature brain following intrauterine asphyxia. Fetal sheep at 90 d of gestation were subjected to umbilical cord occlusion. Melatonin (20 mg/kg, n = 9) or vehicle (n = 10) was administered IV to the fetus, starting 10 min after the start of reperfusion and continued for 6 h. Melatonin treatment resulted in a slower recovery of fetal blood pressure following umbilical cord occlusion, but without changes in fetal heart rate, acid base status or mortality. The production of 8-isoprostanes following umbilical cord occlusion was attenuated and there was a reduction in the number of activated microglia cells and TUNEL-positive cells in melatonin treated fetuses, suggesting a protective effect of melatonin. In conclusion, this study shows that melatonin attenuates cell death in the fetal brain in association with a reduced inflammatory response in the blood and the brain following intrauterine asphyxia in mid-gestation fetal sheep.

Lipoic acid supplementation prevents cyclosporine-induced hypertension and nephrotoxicity in spontaneously hypertensive rats

BACKGROUND

Cyclosporine (CsA) has significantly improved long-term survival after organ transplantations. Hypertension and nephrotoxicity are common side effects during CsA treatment and are aggravated by high salt intake.

OBJECTIVE

To examine whether lipoic acid (LA), a natural antioxidant that scavenges reactive oxygen species and regenerates/recycles endogenous antioxidants, could prevent CsA-induced hypertension and nephrotoxicity.

METHODS

Six-week-old spontaneously hypertensive rats (SHR) on a high-sodium diet (NaCl 6%) received CsA [5 mg/kg subcutaneously (s.c.)] alone or in combination with LA (0.5% w/w) for 6 weeks. Blood pressure, arterial functions, and tissue morphology were determined. Immunohistochemistry, quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and high-pressure liquid chromatography were used for kidney and heart samples.

RESULTS

CsA induced severe hypertension, cardiac hypertrophy, endothelial dysfunction, and pronounced albuminuria. Histologically, the kidneys showed severe thickening of the media of the afferent arteries with fibrinoid necrosis, perivascular monocyte/macrophage infiltration and nitrotyrosine overexpression. CsA induced the expression of fibrogenic connective tissue growth factor both in the heart and kidneys. The detrimental effects of CsA were associated with upregulation of myocardial atrial natriuretic peptide (ANP) mRNA expression, paradoxical activation of the renin-angiotensin system (RAS), induction of renal reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase, and overexpression of oxidative stress-induced transcription factor NRF2. LA lowered blood pressure, ameliorated cardiac hypertrophy and endothelial dysfunction, and totally normalized albuminuria. In LA-treated rats, renal and cardiac morphologies were indistinguishable from those of SHR controls. CsA-induced myocardial ANP and connective tissue growth factor (CTGF) mRNA overexpression, RAS activation, NADPH oxidase induction, and NRF2 overexpression were prevented by LA. LA induced the mRNA expression of gamma-glutamylcysteine ligase, the rate-limiting enzyme in glutathione synthesis, and markedly increased hepatic cysteine and glutathione concentrations.

CONCLUSIONS

Our findings suggest a salutary role for lipoic acid supplementation in the prevention of CsA-induced hypertension and nephrotoxicity, and underscore the importance of increased oxidative stress in the pathogenesis of CsA toxicity.

Kidneys with heavy proteinuria show fibrosis, inflammation, and oxidative stress, but no tubular phenotypic change

BACKGROUND

Sustained proteinuria is a major factor leading to kidney fibrosis and end-stage renal failure. Tubular epithelial cells are believed to play a crucial role in this process by producing mediators leading to fibrosis and inflammation. Congenital nephrotic syndrome of the Finnish type (NPHS1) is a genetic disease caused by mutations in a podocyte protein nephrin, which leads to constant heavy proteinuria from birth. In this work we studied the tubulointerstitial changes that occur in NPHS1 kidneys during infancy.

METHODS

The pathologic lesions and expression of profibrotic and proinflammatory factors in nephrectomized NPHS1 kidneys were studied by immunohistochemistry, Western blotting, and cytokine antibody array. Oxidative stress in kidneys was assessed by measurement of gluthatione redox state.

RESULTS

The results indicated that (1) severe tubulointerstitial lesions developed in NPHS1 kidneys during infancy; (2) tubular epithelial cells did not show transition into myofibroblasts as studied by the expression of vimentin, alpha-smooth muscle actin (alpha-SMA), collagen, and matrix metalloproteinases 2 and 9 (MMP-2 and -9); (3) the most abundant chemokines in NPHS1 tissue were neutrophil activating protein-2 (NAP-2), macrophage inhibiting factor (MIF), and monocyte chemoattractant protein-1 (MCP-1); (4) monocyte/macrophage cells expressing CD14 antigen were the major inflammatory cells invading the interstitium; (5) the arteries and arterioles showed intimal hypertrophy, but the microvasculature in NPHS1 kidneys remained quite normal; and (6) excessive oxidative stress was evident in NPHS1 kidneys.

CONCLUSION

Heavy proteinuria in NPHS1 kidneys was associated with interstitial fibrosis, inflammation, and oxidative stress. The tubular epithelial cells, however, were resistant to proteinuria and did not show epithelial-mesenchymal transition.

Expanding screening for rare metabolic disease in the newborn: an analysis of costs, effect and ethical consequences for decision-making in Finland

AIM

Currently, the only metabolic disorder that newborns are screened for in Finland is congenital hypothyroidism. A proposal to start a pilot study on screening for other rare metabolic diseases using tandem mass spectrometry prompted a health technology assessment project on the effect and costs of expanded newborn screening programme options.

METHOD

A modelling study using data from current published studies, healthcare registers and expert opinion.

RESULTS

The annual running cost of screening 56,000 newborns for the chosen five disorders (congenital adrenal hyperplasia, medium-chain acyl-CoA dehydrogenase deficiency [MCADD], long chain 3-hydroxyacyl-CoA dehydrogenase deficiency [LCHADD], phenylketonuria [PKU] and glutaric aciduria type 1 [GA 1]) was estimated to be euros 2.5 million or euros 45 per newborn when starting costs were included. The costs per quality-adjusted life year (QALY) gained are a maximum of euros 25,500. Prevention of severe handicap in one newborn would reduce the costs to a maximum of euros 18,000 per QALY gained.

CONCLUSIONS

Expanding the Finnish neonatal screening programme would require a new organization. The cost-effectiveness, resources, ethics and equity need to be considered when deciding in favour of or against starting a new screening programme.

Thiol metabolism in preterm infants during the first week of life

BACKGROUND

Oxidative stress is implicated in the pathogenesis of several complications of prematurity. The glutathione cycle is one of the most important intracellular antioxidant systems. The synthesis of glutathione may not be adequate in preterm neonates because of the low levels of cysteine available. The aim of this study was to evaluate cysteine and glutathione metabolism during the first week of life in preterm infants.

METHODS

Plasma and erythrocyte thiol concentrations were measured in 78 preterm infants with a birthweight of 500-1500 g, and erythrocyte glutamate-cysteine ligase (GCL), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferases (GST) and glucose 6-phosphatedehydrogenase (G6PDH) in 26 infants with a birthweight of 1000-1500 g.

RESULTS

The mean (SD) plasma glutathione concentration increased from day 0 to day 1 (14.9 (7.1) vs. 27.7 (11.9) micromol/L, p < 0.001), and then decreased. The plasma cysteine concentration changed in the opposite direction (172 (59) vs. 129 (42) micromol/L, p < 0.01). In infants with respiratory distress syndrome (RDS) the mean plasma glutathione concentration, but not cysteine, was lower on day 0 compared with infants without RDS (11.7 (5.2) vs. 21.4 (5.6) micromol/L, p < 0.01). Erythrocyte glutathione concentration decreased during the first week of life, whereas erythrocyte cysteine concentration increased significantly from day 3 to day 7 (p < 0.01). Erythrocyte cysteine and glutathione concentrations had a positive correlation. The GCL and GR activities did not change, but GST and G6PDH activities decreased during the first week (p < 0.01). GPx activity decreased until day 3 (p < 0.01) and was higher on day 0 and day 1 in infants with RDS.

CONCLUSIONS

Very low birthweight infants have an initial increase in plasma glutathione and initial decrease in plasma cysteine level during the first week of life, and also a positive correlation between erythrocyte cysteine and glutathione levels.

Renal xanthine oxidoreductase activity during development of hypertension in spontaneously hypertensive rats

BACKGROUND

Hyperuricaemia and reactive oxygen species have recently been associated with essential hypertension. Xanthine oxidoreductase (XOR) produces urate and, in its oxidase isoform, reactive oxygen species also. Our previous studies indicated that hypertension-prone rat strains have greater renal XOR activity than their normotensive counterparts, and that dietary sodium modifies renal XOR activity.

OBJECTIVE

To clarify whether renal XOR induction precedes or follows the development of hypertension.

METHODS

Five-week-old spontaneously hypertensive rats (SHRs) and Wistar-Kyoto (WKY) rats were kept for 3-8 weeks on low sodium (0.3% salt w/w) or high sodium (6.0% salt w/w) intakes, with or without allopurinol, an inhibitor of XOR, to study the possible pathogenetic role of XOR in hypertension. Systolic blood pressure (SBP), renal XOR activity and mRNA expression were measured.

RESULTS

Regardless of sodium intake, renal XOR activity increased twofold during growth in SHRs, but not in WKY rats. SBP increased from 122 +/- 4 to 241 +/- 13 mmHg in SHRs kept on the high-sodium diet and to 204 +/- 11 mmHg in those on the low-sodium diet. At the end of the experiment, renal XOR activity correlated with SBP in SHRs. Allopurinol prevented hypertension-induced left ventricular and renal hypertrophy in SHRs, but had negligible effect on blood pressure.

CONCLUSION

Renal XOR induction in SHRs does not precede the development of hypertension, but progress concomitantly with an increase in SBP. The results indicate a role for locally synthesized XOR in the development of hypertension-associated end-organ damage, but no major role in the development of hypertension.

Entacapone protects from angiotensin II-induced inflammation and renal injury

OBJECTIVES AND DESIGN

Angiotensin II (Ang II)-induced renal damage is associated with perivascular inflammation and increased oxidative stress. We tested the hypothesis whether entacapone, a catechol-O-methyltransferase (COMT) inhibitor exerting antioxidative and anti-inflammatory properties, protects against the Ang II-induced inflammatory response and end-organ damage.

METHODS

Samples from double-transgenic rats harbouring human renin and human angiotensinogen genes (dTGR) and normotensive Sprague-Dawley rats (SD) were assessed by light microscopy, immunohistochemistry, reverse transcriptase-polymerase chain reaction (RT-PCR), and high pressure liquid chromatography. The effects of entacapone treatment for 3 weeks were examined in dTGR and SD.

RESULTS

Entacapone completely prevented cardiovascular mortality and decreased albuminuria by 85% in dTGR. Entacapone ameliorated Ang II-induced vascular and glomerular damage, leucocyte infiltration, and intercellular adhesion molecule-1 (ICAM-1) overexpression in the kidneys. Serum 8-isoprostane concentration, as well as renal nitrotyrosine and 8-hydroxydeoxyguanosine expressions, all markers of oxidative stress, were markedly increased in dTGR and normalized by entacapone. Entacapone also decreased p22phox mRNA expression in the kidney. COMT expression was increased by 500% locally in the renal vascular wall in dTGR; however, COMT activity in the whole kidney remained unchanged. Urinary dopamine excretion, a marker of renal dopaminergic tone, was decreased by 50% in untreated dTGR. Even though entacapone decreased renal COMT activity by 40%, the renal dopaminergic tone remained unchanged in entacapone-treated dTGR.

CONCLUSION

Our findings suggest that entacapone provides protection against Ang II-induced renal damage through antioxidative and anti-inflammatory mechanisms, rather than by COMT inhibition-induced changes in renal dopaminergic tone.

Plasma 8-isoprostane is increased in preterm infants who develop bronchopulmonary dysplasia or periventricular leukomalacia

Our aim was to assess the plasma free 8-epi-prostaglandin F(2alpha) (8-isoprostane) and ascorbyl radical as risk indicators for oxidative damage in extremely low birth weight infants (ELBWIs) and the effect of N-acetylcysteine (NAC) on these markers. Plasma samples were collected on days 3 and 7 of life from infants who were enrolled in a randomized, controlled trial in which i.v. NAC or placebo was administered to ELBWIs during the first week of life, with the aim of preventing bronchopulmonary dysplasia (BPD). Plasma 8-isoprostane was analyzed in 83 infants using an enzyme immunoassay kit. Ascorbyl radical concentration was measured in 61 infants with electron spin resonance spectroscopy. The 8-isoprostane concentrations were similar in the NAC and placebo groups. In infants who later developed BPD or died (n = 29), the median (range) 8-isoprostane concentration was significantly higher (p = 0.001) on day 3 and day 7 [50.0 pg/mL (19-360) and 57.0 pg/mL (14-460), respectively] than in survivors without BPD [n = 54; 34.5 pg/mL (5-240) and 39.5 pg/mL (7-400), respectively]. The 8-isoprostane levels increased significantly more (p < 0.05) in infants who later developed periventricular leukomalacia. NAC treatment or the later development of BPD was not related to the ascorbyl radical levels. The ascorbyl radical level decreased significantly in all groups from day 3 to day 7, but the difference between the groups was not significant. The mean (SD) ascorbyl radical level on day 3 was significantly higher (p < 0.01) in infants who later developed periventricular leukomalacia [287 (124) versus 194 (90)]. These data suggest that plasma 8-isoprostane could serve as a marker in assessing the risk for BPD development in ELBWIs.

Mechanisms of beta cell death during restricted and unrestricted enterovirus infection

Coxsackie B virus (CVB-5) infections potentially trigger and accelerate pancreatic beta cell damage leading to type 1 diabetes. In vivo, all viruses face natural resistance mediated by various host factors which restrict the progression of infection. Thus, the aims of this study were to generate a tissue culture model of restricted coxsackie B virus infection in primary islet cells by preventing the production of viral progeny with a selective inhibitor of viral RNA replication and to investigate the mechanisms of virus-induced islet cell death during productive and restricted infective conditions. Cultured foetal porcine islet cells were infected effectively with the prototype strain of coxsackievirus B5 (CVB-5). Nuclear viability stainings and electron microscopy showed productive infection to result in dominantly necrotic cell death with additional slight induction of apoptosis during the 7 days of follow-up. The restricted conditions were created by addition of guanidine-hydrochloride (G-HCl) into culture medium. At 1 mM concentration, it significantly protected the infected cells from necrosis and thus maintained high viability. This was associated with increased significantly apoptosis. In perifusion analysis, the cellular ability to release insulin was reduced, although the metabolic integrity was preserved as shown by MTT-analysis and cellular ATP levels. These data show that restriction of CVB-5 replication with G-HCl protects islet cells against virus-induced necrosis. However, restriction of viral replication shifts the mechanism of cell death from necrosis toward apoptosis. A slowly progressing subclinical infection of islets could thus lead to increased beta-cell apoptosis.

Glutathione depletion and cardiomyocyte apoptosis in viral myocarditis

BACKGROUND

The course of viral myocarditis is highly variable. Oxidative stress and Bcl-2 family genes may play a role in its pathogenesis by regulating the amount of cardiomyocyte apoptosis. Apoptosis is difficult to detect and quantify in vivo. Therefore, we set to look for indicators of this potentially preventable form of cell death during various phases of experimental murine coxsackievirus B3 myocarditis.

METHODS

BALB/c mice were infected with the cardiotropic coxsackievirus B3 variant. Glutathione (HPLC), cardiomyocyte apoptosis (TUNEL and caspase-3 cleavage), Bax and Bcl-X(L) mRNA expression (real time RT-PCR), histopathology and viral replication (plaque assay and real time RT-PCR) were measured from day 3 to day 20 after infection.

RESULTS

Infection caused severe myocarditis and led to progressive decrease of plasma glutathione levels. Myocardial mRNA levels of pro-apoptotic Bax and antiapoptotic Bcl-X(L) were significantly increased from day 3 onwards. Bax mRNA and ratio of Bax to Bcl-X(L) correlated with cardiomyocyte apoptosis (r = 0.77, P = < 0.001 and r 0.51, P < 0.01, respectively). Cardiomyocyte apoptosis was highest on day 5, coinciding with a rapid decline in plasma glutathione (r = -0.52, P = 0.003).

CONCLUSIONS

Systemic oxidative stress as indicated by decreased plasma glutathione levels coincides with cardiomyocyte apoptosis in experimental coxsackievirus myocarditis. Decreased plasma glutathione levels and changes in cardiac Bax and Bcl-X(L) mRNA expression identify a phase of myocarditis in which the potentially preventable cardiomyocyte apoptosis is mostly observed.

Mechanisms of coxsackievirus B5 mediatedβ-cell death depend on the multiplicity of infection

Coxsackievirus infections may trigger and accelerate pancreatic beta-cell death, leading to type I diabetes. Unrestricted coxsackievirus B5 replication in cultured beta-cells inoculated with high multiplicity leads to rapid lytic cell death. Evidence from other virus-host cell systems indicates that host cell responses to infection may depend on the multiplicity of infection (MOI). Thus, the aim of this study was to compare the mechanisms of beta-cell death during high versus low multiplicity of coxsackievirus B5 infection. Cultures of highly differentiated mouse insulinoma cells and primary adult human islets were infected with coxsackievirus B5 at multiplicities of >1,000 or <0.5 TCID50 per cell. The results of nuclear morphology and viability stainings, TUNEL staining and electrophoretic DNA fragmentation analysis showed high multiplicity infection to predominantly induce necrosis and transient apoptosis. In low multiplicity culture, however, necrosis was only moderately induced and apoptosis increased steadily with time. This was best demonstrated by a tenfold higher apoptosis/necrosis ratio than after high multiplicity inoculation. Expression of gamma-glutamyl cysteine synthetase increased in both infective cultures but the level of intracellular glutathione permanently depleted only at high multiplicity and recovered fully at low multiplicity. Thus, apoptosis represents an important mechanism of beta-cell death after low multiplicity of coxsackievirus B5 infection. This process is associated with maintenance of a physiological intracellular glutathione profile differing dramatically from the high multiplicity infection during which necrosis dominates and intracellular thiol balance deteriorates. These data suggest that the pattern and mechanisms of coxsackievirus B5 infection induced beta-cell death depend on the MOI.

N-acetylcysteine does not prevent bronchopulmonary dysplasia in immature infants: a randomized controlled trial

OBJECTIVE

To evaluate whether N-acetylcysteine (NAC) infusion during the first week of life reduces the risk of death or bronchopulmonary dysplasia (BPD) in infants with extremely low birth weight. Study design In a Nordic multicenter, double-blind trial, infants (n=391) weighing 500 to 999 g and on ventilator or nasal continuous positive airway pressure were randomized before the age of 36 hours to receive NAC 16 to 32 mg/kg/d (n=194) or placebo (n=197) intravenously for 6 days. Primary end points were death or BPD, defined as supplementary oxygen requirement at 36 weeks' gestational age.

RESULTS

There was no difference in the combined incidence of the primary end points death or BPD, 51% vs. 49%, between the NAC group and control group. Also similar was the incidence of BPD in survivors at 36 weeks' gestational age, 40% vs. 40%, and the mean oxygen requirement at the age of 28 days, 31.2% vs. 30.7%, respectively. The severity of BPD was similar in both groups.

CONCLUSIONS

A 6-day course of intravenous N-acetylcysteine at the dosage used does not prevent BPD or death in infants with extremely low birth weight.

Inborn Errors in Metabolism and 4-Boronophenylalanine–Fructose-Based Boron Neutron Capture Therapy

Infusions of boronophenylalanine-fructose complex (BPA-F), at doses up to 900 mg/kg of BPA and 860 mg/kg of fructose, have been used to deliver boron to cancer tissue for boron neutron capture therapy (BNCT). In patients with phenylketonuria (PKU), phenylalanine accumulates, which is harmful in the long run. PKU has been an exclusion criterion for BPA-F-mediated BNCT. Fructose is harmful to individuals with hereditary fructose intolerance (HFI) in amounts currently used in BNCT. The harmful effects are mediated through induction of hypoglycemia and acidosis, which may lead to irreversible organ damage or even death. Consequently, HFI should be added as an exclusion criterion for BNCT if fructose-containing solutions are used in boron carriers. Non-HFI subjects may also develop symptoms, such as gastrointestinal pain, if the fructose infusion rate is high. We therefore recommend monitoring of glucose levels and correcting possible hypoglycemia promptly. Except for some populations with extremely low PKU prevalence, HFI and PKU prevalences are similar, approximately 1 or 2 per 20,000.

Lipoic acid supplementation prevents angiotensin II-induced renal injury

BACKGROUND

Angiotensin II (Ang II)-induced renal injury is associated with perivascular inflammation, cell proliferation, and increased superoxide production in the vascular wall. We tested whether lipoic acid, an endogenous antioxidant, protects against the Ang II-induced inflammatory response and end-organ damage.

METHODS

Light microscopy, immunohistochemistry, electrophoretic mobility shift assay, Northern blots, and high-pressure liquid chromatography (HPLC) were used in kidneys from double transgenic rats (dTGR) harboring human renin and angiotensinogen genes and normotensive Sprague Dawley (SD) rats. The effects of lipoic acid supplementation for three weeks were examined in dTGR and SD rats.

RESULTS

Lipoic acid effectively prevented Ang II-induced glomerular and vascular damage in the kidneys and completely prevented the development of albuminuria. Ang II-induced leukocyte infiltration and cell proliferation in the kidney were attenuated. The redox-sensitive transcription factors nuclear factor (kappa) B (NF-kappa B) and activator protein-1 (AP-1) in the kidneys were increased in dTGR compared with SD, and were effectively reduced. Renal glutathione levels were much higher in dTGR than in SD, while the opposite was true for cysteine levels. These results suggested increased renal glutathione oxidation in dTGR, leading to cysteine shortage. Lipoic acid partly prevented renal cysteine depletion and increased hepatic cysteine and glutathione concentrations. This effect was accompanied by increased hepatic gamma-glutamylcysteine synthetase mRNA expression.

CONCLUSION

Our in vivo results suggest that lipoic acid protects against Ang II-induced renal injury through anti-inflammatory/antioxidative mechanisms. The effects are associated with decreased NF-kappa B and AP-1 activation, as well as improved thiol homeostasis.

Posttranslational inactivation of human xanthine oxidoreductase by oxygen under standard cell culture conditions

Xanthine oxidoreductase (XOR) catalyzes the final reactions of purine catabolism and may account for cell damage by producing reactive oxygen metabolites in cells reoxygenated after hypoxia. We found a three- to eightfold higher XOR activity in cultured human bronchial epithelial cells exposed to hypoxia (0.5-3% O2) compared with cells grown in normoxia (21% O2) but no difference in XOR protein or mRNA. XOR promoter constructs failed to respond to hypoxia. The cellular XOR activity at 3% O2 returned to basal levels when the cells were returned to 21% O2, and hyperoxia (95% O2) abolished enzyme activity with no change in XOR protein. Our data suggest reversible enzyme inactivation by oxygen or its metabolites. NADH was normally oxidized by the oxygen-inactivated enzyme, which rules out damage to the flavin adenine dinucleotide cofactor. Hydrogen peroxide partially inactivated the molybdenum center of XOR, as shown by a parallel decrease in XOR-catalyzed xanthine oxidation and dichlorophenolindophenol reduction. We conclude that the transcription or translation of XOR is not influenced by hypoxia or hyperoxia. Instead, the molybdenum center of XOR is posttranslationally inactivated by oxygen metabolites in "normal" (21% O2) cell culture atmosphere. This inactivation is reversed in hypoxia and accounts for the apparent induction.

Physical exercise-induced hyperinsulinemic hypoglycemia is an autosomal-dominant trait characterized by abnormal pyruvate-induced insulin release

We have identified patients in whom strenuous physical exercise leads to hypoglycemia caused by inappropriate insulin release (exercise-induced hyperinsulinism [EIHI]). The aim of the present study was to test the hypothesis that the increased levels of lactate and/or pyruvate during anaerobic exercise would trigger the aberrant insulin secretion in these patients. A total of 12 patients (8 women and 4 men from two families) were diagnosed with EIHI, based on hypoglycemia and a more than threefold increase in plasma insulin induced by a 10-min bicycle exercise test. The mode of inheritance was autosomal dominant in these families. The acute response of insulin release to a bolus of intravenous pyruvate (13.9 mmol/1.73 m(2)) was studied in the patients and eight healthy control subjects. Insulin secretion did not respond to the pyruvate bolus in healthy control subjects. However, all EIHI patients responded to pyruvate, displaying a brisk increase in plasma insulin. The 1 + 3-min peak response was 5.6-fold in the patients and 0.9-fold in the control subjects (P < 0.001). To test the hypothesis that the pathogenesis of EIHI would involve monocarboxylate transport or metabolism in the beta-cell, we sequenced the genes encoding the known monocarboxylate transporter proteins and tested the transport of pyruvate into patient fibroblasts. The results revealed normal coding sequences and pyruvate transport. In conclusion, EIHI represents a new autosomal-dominant hyperinsulinemia syndrome that may be more common than has been realized. The pyruvate test provides a simple, safe, and specific diagnostic test for this condition.

Regulation of xanthine oxidoreductase by intracellular iron

Xanthine oxidoreductase (XOR) may produce reactive oxygen species and play a role in ischemia-reperfusion injury. Because tissue iron levels increase after ischemia, and because XOR contains functionally critical iron-sulfur clusters, we studied the effects of intracellular iron on XOR expression. Ferric ammonium citrate and FeSO(4) elevated intracellular iron levels and increased XOR activity up to twofold in mouse fibroblast and human bronchial epithelial cells. Iron increased XOR protein and mRNA levels, whereas protein and RNA synthesis inhibitors abolished the induction of XOR activity. A human XOR promoter construct (nucleotides +42 to -1937) was not induced by iron in human embryonic kidney cells. Hydroxyl radical scavengers did not block induction of XOR activity by iron. Iron chelation by deferoxamine (DFO) decreased XOR activity but did not lower endogenous XOR protein or mRNA levels. Furthermore, DFO reduced the activity of overexpressed human XOR but not the amount of immunoreactive protein. Our data show that XOR activity is transcriptionally induced by iron but posttranslationally inactivated by iron chelation.

Dose-dependent cysteine-mediated protection of insulin-producing cells from damage by hydrogen peroxide

AIMS/HYPOTHESIS

Oxidative damage is believed to play a key role in the process of pancreatic beta cell destruction leading to type 1 diabetes. The beta cells are sensitive to oxidative stress because their intracellular anti-oxidative defence mechanisms are weak. The defence mechanisms depend heavily on glutathione, the synthesis of which is dependent on the availability of cysteine. We investigated whether an increased amount of cysteine available could protect beta cells from oxidative damage.

METHODS

Rat insulinoma cells (RINm5F) were exposed to 50 or 100 microM hydrogen peroxide in the presence of three different cysteine concentrations (0.1, 1 and 5mM). Cell viability was analyzed by vital staining and the cellular metabolic status by C,N-diphenyl-N'-4,5-dimethyl thiazol-2-yl tetrazolium bromide (MTT) analysis. Intracellular insulin, DNA and glutathione contents were measured. The mechanism of death was further clarified by gel electrophoretic DNA fragmentation analysis.

RESULTS

Hydrogen peroxide decreased cell viability and induced functional impairment. Vital staining indicated that 1mM cysteine effectively protected the cells. The protective effect was confirmed by the MTT assay showing preserved metabolic integrity, and by measurements of intact intracellular insulin and DNA content. Cysteine increased intracellular glutathione. Gel electrophoretic analysis of DNA revealed hydrogen peroxide-induced apoptotic fragmentation. This was also abolished by 1mM cysteine. The therapeutic window of cysteine was narrow: 0.1mM cysteine provided inadequate protection, and 5mM cysteine was already toxic in this setting.

CONCLUSION

A proper dose of cysteine could provide a safe and effective means to protect beta cells from oxidative damage.

Increased sensitivity of homozygous Sod2 mutant mice to oxygen toxicity

Induction or overexpression of pulmonary manganese superoxide dismutase (MnSOD) has been shown to protect against oxygen (O2) toxicity. Genetic inactivation of MnSOD (Sod2) results in multiple organ failure and early neonatal death. However, lungs or O2-tolerance of Sod2 knockout mice have not been investigated. We evaluated survival, lung histopathology, and other pulmonary antioxidants (glutathione cycle) of homozygous (-/-) and heterozygous (+/-) Sod2 mutant mice compared with wild-type controls (Sod2+/+) following 48 h exposure to either room air or to O2. The ability of antioxidant N-acetylcysteine to compensate for the loss of MnSOD was explored. Mortality of Sod2-/- mice increased from 0% in room air to 18 and 83% in 50 and 80% O2, respectively. N-acetylcysteine did not alter mortality of Sod2-/- mice. Histopathological analysis revealed abnormalities in saccules of Sod2-/- mice exposed either to room air or to 50% O2 suggestive of delayed postnatal lung development. In 50% O2, activities of glutamate-cysteine ligase (GCL) (previously known as gamma-glutamylcysteine synthetase, gamma-GCS) and glutathione peroxidase increased in Sod2-/- (35 and 70%, respectively) and Sod2+/- (12 and 70%, respectively) mice, but glutathione levels remained unaltered. We conclude that MnSOD is required for normal O2 tolerance and that in the absence of MnSOD there is a compensatory increase in pulmonary glutathione-dependent antioxidant defense in hyperoxia.

Endothelial dysfunction and xanthine oxidoreductase activity in rats with human renin and angiotensinogen genes

We examined whether xanthine oxidoreductase (XOR), a hypoxia-inducible enzyme capable of generating reactive oxygen species, is involved in the onset of angiotensin (Ang) II-induced vascular dysfunction in double-transgenic rats (dTGR) harboring human renin and human angiotensinogen genes. In 7-week-old hypertensive dTGR, the endothelium-mediated relaxation of noradrenaline (NA)-precontracted renal arterial rings to acetylcholine (ACh) in vitro was markedly impaired compared with Sprague Dawley rats. Preincubation with superoxide dismutase (SOD) improved the endothelium-dependent vascular relaxation, indicating that in dTGR, endothelial dysfunction is associated with increased superoxide formation. Preincubation with the XOR inhibitor oxypurinol also improved endothelium-dependent vascular relaxation. The endothelium-independent relaxation to sodium nitroprusside was similar in both strains. In dTGR, serum 8-isoprostaglandin F(2alpha), a vasoconstrictor and antinatriuretic arachidonic acid metabolite produced by oxidative stress, was increased by 100%, and the activity of XOR in the kidney was increased by 40%. Urinary nitrate plus nitrite (NO(x)) excretion, a marker of total body NO generation, was decreased by 85%. Contractile responses of renal arteries to Ang II, endothelin-1 (ET-1), and NA were decreased in dTGR, suggesting hypertension-associated generalized changes in the vascular function rather than a receptor-specific desensitization. Valsartan (30 mg/kg PO for 3 weeks) normalized blood pressure, endothelial dysfunction, and the contractile responses to ET-1 and NA. Valsartan also normalized serum 8-isoprostaglandin F(2alpha) levels, renal XOR activity, and, to a degree, NO(x) excretion. Thus, overproduction of Ang II in dTGR induces pronounced endothelial dysfunction, whereas the sensitivity of vascular smooth muscle cells to nitric oxide is unaltered. Ang II-induced endothelial dysfunction is associated with increased oxidative stress and vascular xanthine oxidase activity.