In vivo epigenetic effects induced by engineered nanomaterials: A case study of copper oxide and laser printer-emitted engineered nanoparticles

Evidence continues to grow on potential environmental health hazards associated with engineered nanomaterials (ENMs). While the geno- and cytotoxic effects of ENMs have been investigated, their potential to target the epigenome remains largely unknown. The aim of this study is two-fold: 1) determining whether or not industry relevant ENMs can affect the epigenome in vivo and 2) validating a recently developed in vitro epigenetic screening platform for inhaled ENMs. Laser printer-emitted engineered nanoparticles (PEPs) released from nano-enabled toners during consumer use and copper oxide (CuO) were chosen since these particles induced significant epigenetic changes in a recent in vitro companion study. In this study, the epigenetic alterations in lung tissue, alveolar macrophages and peripheral blood from intratracheally instilled mice were evaluated. The methylation of global DNA and transposable elements (TEs), the expression of the DNA methylation machinery and TEs, in addition to general toxicological effects in the lung were assessed. CuO exhibited higher cell-damaging potential to the lung, while PEPs showed a greater ability to target the epigenome. Alterations in the methylation status of global DNA and TEs, and expression of TEs and DNA machinery in mouse lung were observed after exposure to CuO and PEPs. Additionally, epigenetic changes were detected in the peripheral blood after PEPs exposure. Altogether, CuO and PEPs can induce epigenetic alterations in a mouse experimental model, which in turn confirms that the recently developed in vitro epigenetic platform using macrophage and epithelial cell lines can be successfully utilized in the epigenetic screening of ENMs.     

Genetic predisposition for adult lactose intolerance and relation to diet, bone density, and bone fractures.

Evidence that genetic disposition for adult lactose intolerance significantly affects calcium intake, bone density, and fractures in postmenopausal women is presented. PCR-based genotyping of lactase gene polymorphisms may complement diagnostic procedures to identify persons at risk for both lactose malabsorption and osteoporosis. INTRODUCTION: Lactase deficiency is a common autosomal recessive condition resulting in decreased intestinal lactose degradation. A -13910 T/C dimorphism (LCT) near the lactase phlorizin hydrolase gene, reported to be strongly associated with adult lactase nonpersistence, may have an impact on calcium supply, bone density, and osteoporotic fractures in the elderly. MATERIALS AND METHODS: We determined LCT genotypes TT, TC, and CC in 258 postmenopausal women using a polymerase chain reaction-based assay. Genotypes were related to milk intolerance, nutritional calcium intake, intestinal calcium absorption, bone mineral density (BMD), and nonvertebral fractures. RESULTS: Twenty-four percent of all women were found to have CC genotypes and genetic lactase deficiency. Age-adjusted BMD at the hip in CC genotypes and at the spine in CC and TC genotypes was reduced by -7% to -11% depending on the site measured (p = 0.04). LCT(T/C-13910) polymorphisms alone accounted for 2-4% of BMD in a multiple regression model. Bone fracture incidence was significantly associated with CC genotypes (p = 0.001). Milk calcium intake was significantly lower (-55%, p = 0.004) and aversion to milk consumption was significantly higher (+166%, p = 0.01) in women with the CC genotype, but there were no differences in overall dietary calcium intake or in intestinal calcium absorption test values. CONCLUSION: The LCT(T/C-13910) polymorphism is associated with subjective milk intolerance, reduced milk calcium intake, and reduced BMD at the hip and the lumbar spine and may predispose to bone fractures. Genetic testing for lactase deficiency may complement indirect methods in the detection of individuals at risk for both lactose malabsorption and osteoporosis.     

The effects of hyperbaric oxygen therapy on oxidative stress,inflammation, and symptoms in children with autism: an open-label pilot study

Background  

Recently, hyperbaric oxygen therapy (HBOT) has increased in popularity as a treatment for autism. Numerous studies document oxidative stress and inflammation in individuals with autism; both of these conditions have demonstrated improvement with HBOT, along with enhancement of neurological function and cognitive performance. In this study, children with autism were treated with HBOT at atmospheric pressures and oxygen concentrations in current use for this condition. Changes in markers of oxidative stress and inflammation were measured. The children were evaluated to determine clinical effects and safety.     

S-Adenosylhomocysteine, but not homocysteine, is toxic to yeast lacking cystathionine β-synthase

Elevated plasma homocysteine is associated with a variety of diseases in humans including coronary heart disease, stroke, peripheral vascular disease, and birth defects. However, the mechanism by which plasma homocysteine affects cells is unknown. We have examined the growth of isogenic wild-type and cystathionine beta-synthase (CBS) deficient yeast in response to homocysteine and its immediate metabolic precursor, S-adenosylhomocysteine (SAH). CBS deficient yeast export significantly more homocysteine into the media than wild-type yeast and have elevated internal pools of homocysteine and SAH. We found that 5 mM homocysteine added to the media had very little effect on the growth of wild-type or CBS deficient yeast, although intracellular homocysteine concentrations increased five- to tenfold. In contrast, as little as 25 microM S-adenosylhomocysteine inhibited the growth of CBS deficient yeast, but had no effect on wild-type yeast. Measurements of the intracellular S-adenosylmethionine (SAM) and SAH indicate that CBS deficient yeast contain reduced SAM/SAH ratios relative to wild-type, and this ratio is further reduced by adding SAH to the media. Growth inhibition by SAH in CBS deficient yeast can be totally reversed by addition of SAM to the media, indicating that the ratio and not absolute level is critical for cell growth. These results suggest that CBS plays a key role in the regulation of the SAM/SAH ratio inside cells and that excessive perturbations of this ratio can inhibit growth. We hypothesize that elevated extracellular homocysteine present in humans may reflect an altered intracellular SAM/SAH ratio and that this may be related to disease pathogenesis.     

Prevalence of persistent vegetative state/apallic syndrome in Vienna

The aim of the project was to survey the hospital prevalence of apallic syndrome in a federal state in Austria at an exact point in time. To achieve this, a point prevalence study was carried out on 28 November 2001 in the Vienna region. The central element was a questionnaire, which provided an exact recording of the patients' condition. An additional preliminary task was to check all the discharge diagnoses in the hospitals of the Vienna Hospital Association (Wiener Krankenanstalten Verbund) between 1996 and 2000 according to the ICD-9 diagnoses for apallic syndrome. These data should serve to cross-check the recorded results. All hospitals (n = 48) and nursing facilities (n = 44) in Vienna were included in this investigation. As the aim of the study was to record the prevalence of apallic syndrome in the population of Vienna, four patients of the group with full-stage apallic syndrome (n = 36) were excluded as they were from other federal states. In total, 32 hospital patients who met the clinical criteria for apallic syndrome (full-stage) were recorded. The point prevalence of apallic syndrome was 1.9/100,000 inhabitants. As a result of this study, the exact survey of hospital prevalence of apallic syndrome could be found. As a consequence, the Viennese government has developed a rehabilitation concept for patients with apallic syndrome in Vienna.     

Modification of pancreatic carcinogenesis in the hamster model. 6. The effect of ductal ligation and excision

The effect of ligation and excision of the pancreatic duct in pancreatic carcinogenesis was examined in the hamster model. Animals were treated with a single dose (20 mg/kg body weight) of N-nitrosobis(2-oxopropyl)amine (BOP) either immediately (Group 1) or on Days 1 (Group 2), 3 (Group 3) or 7 (Group 4) after ligation and excision of the duct of the splenic lobe. Group 5 received BOP shortly after laparoscopy, and Group 6 consisted of BOP-treated controls. All hamsters were killed 46 weeks after BOP treatment. The results showed that despite advanced atrophy of the splenic lobe distal to the excised duct in Groups 1-4, some hamsters in Groups 2, 3, and 4 showed hyperplasia, dysplasia, and increased mitotic activities of ductal and ductular cells. However, carcinomas in the duct-excised atrophic lobe were found only in Groups 1-3. These data indicate that BOP carcinogenesis is mediated through blood circulation, and that cancer development is not inhibited in the duct-excised lobe for up to 3 days after surgery. However, in the entire pancreas, a significant reduction in tumor incidence was seen when the carcinogen was given immediately, or to a lesser extent, 1 day after surgery, regardless of whether or not excision was made. On the contrary, BOP, when given 3 and 7 days after duct excision, enhanced tumor development in the nonexcised (intact) pancreas, compared with other test groups and with BOP controls. Both inhibition and enhancement seemed due to a proportional decrease and increase, respectively, of BOP-responsive cells throughout the intact pancreas.     

DNA analysis for phospholipase A2 coding sequences of Mycoplasma hominis isolated from women with a normal pregnancy and women with a pregnancy complicated by preterm labour

A possible cause of preterm labour is an increased synthesis of prostaglandins by a phospholipase A2 (PLA2) activity. PLA2 activity has been detected in Mycoplasma hominis. The aim of this study was to test whether chromosomal DNA of M. hominis contains sequences coding for PLA2. M. hominis was cultured in specimens from 5 women with normal pregnancy and 4 in preterm labour. Using sequence alignment, primer pairs for the active part of PLA2 of different species were designed for PCR analysis. No sequences coding for PLA2 could be amplified. Whatever its role in preterm labour, M. hominis is not involved in causing an increase of prostaglandin synthesis. Received: 21 September 1997 / Accepted: 17 January 1998     

Nonsyndromic types of ichthyoses – an update

Ichthyoses are genetically determined Mendelian disorders of cornification (MEDOC) that are characterized by universal scaling. Today we distinguish between non‐syndromic and syndromic forms. Ichthyosis vulgaris is the most frequent type (prevalence 1:100) and is caused by autosomal semi‐dominant filaggrin mutations. It is associated with a higher risk for the development of atopic diseases, such as atopic eczema and allergic rhinitis. Recessive X‐linked ichthyosis (RXLI) occurs almost exclusively in boys; in Germany it has a prevalence of around 1:4,000. It is caused by steroid sulfatase deficiency and is often associated with further clinical problems, such as cryptorchidism (～20%) or social communication deficits, such as attention deficit hyperactivity syndrome (40%) or autism (25%). Autosomal recessive congenital ichthyosis (ARCI) is genetically very heterogeneous and 8 different genes have been identified so far. The most frequent cause of ARCI is a transglutaminase 1 deficiency (prevalence 1:200, 000). Mutations in keratin genes are the cause of the keratinopathic ichthyoses, such as epidermolytic ichthyosis. They manifest at birth and often feature episodes of blistering. Most of these types are inherited as autosomal dominant traits, but autosomal recessive forms have also been described on occasion.