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.     

Epitope load identifies kidney transplant recipients at risk of allosensitization following minimization of immunosuppression

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Antidepressant and other centrally acting drugs regulate glucocorticoid receptor messenger RNA levels in rat brain

The effect of imipramine, desipramine, ketanserin and lithium on Type II glucocorticoid receptor (GR) mRNA levels was studied in rat brain regions involved in the control of the hypothalamo-pituitary-adrenal (HPA) axis, the dysregulation of which has been implicated in the pathophysiology of major depression. Northern blot analysis of Type II GR mRNA showed that treatment of male rats with either desipramine or imipramine increased hypothalamic and hippocampal GR mRNA levels. Upregulation of GR mRNA following administration of imipramine was found in brain regions of female rats, while desipramine had no effect. Ketanserin increased levels of GR mRNA in hippocampus of male, but not female, rats. Lithium also was able to induce important increases rat brain GR mRNA; this effect was particularly marked in females.

We conclude that desipramine, imipramine, ketanserin and lithium can modulate GR mRNA in regions of rat brain involved in the control of the HPA axis and may have a common mechanism of action at the level of the GR gene. Sexual dimorphism for drug regulation of brain GR mRNA content was shown and may be related to sex differences in the prevalence of certain affective disorders.     

Thrombotic Micro‐Angiopathy with Sirolimus‐Based Immunosuppression: Potentiation of Calcineurin‐Inhibitor‐Induced Endothelial Damage?

Thrombotic microangiopathy is a rare but important finding in the context of organ transplantation. Acute renal insufficiency in the setting of hemolysis and thrombocytopenia, a triad that constitutes 'hemolytic uremic syndrome', can be associated with, or triggered by, conditions such as verocytotoxin-producing Escherichia coli, viral infections, malignant hypertension, scleroderma, allograft rejection, lupus erythematosus, pregnancy, and medications including mitomycin C, calcineurin inhibitors, and oral contraceptives. After renal transplantation, it can occur, as either a de novo episode, or recurrent disease. Calcineurin inhibitors have long been associated with post-transplantation thrombotic microangiopathy. Sirolimus has been used as a primary immunosuppressant in patients transplanted with a history of earlier hemolytic-uremic syndrome, and also as rescue therapy in patients with calcineurin-inhibitor-associated thrombotic microangiopathy. We describe four cases where there was significant thrombotic microangiopathy in the context of contemporaneous or contiguous calcineurin inhibitor and sirolimus usage. As the intrarenal cyclosporin concentration is thought to be significantly elevated when cyclosporin and sirolimus are used together, this may explain these findings, and mandates caution in their co-administration.