Estrous cycle-dependent modulation of in vivo microvascular dysfunction after nanomaterial inhalation.

Preconceptive health encompasses male and female reproductive capability. In females, this takes into account each of the stages of the estrous cycle. Microvascular reactivity varies throughout the estrous cycle in response to hormonal changes and in preparation for pregnancy. Microvascular alterations in response to engineered nanomaterial (ENM) exposure have been described within 24-h of inhalation; however, the impact upon the uterine vasculature at differing estrous stages and at late-stage pregnancy is unclear. Female Sprague Dawley (SD) rats (virgin and late stage pregnancy [GD 19]) were exposed to nano-TiO aerosols (173.2 ±â€¯6.4 nm, 10.2 ±â€¯0.46 mg/m3, 5 h) 24-h prior to experimentation leading to a single calculated deposition of 42.2 ±â€¯1.9 µg nano- TiO2 (exposed) or 0 µg (control). Animals were anesthetized, estrous status verified, and prepared for in situ assessment of leukocyte trafficking and vascular function by means of intravital microscopy, Uterine basal arteriolar reactivity was stimulated using iontophoretically applied chemicals: acetylcholine (ACh, 0.025 M; 20, 40, 100, 200 nA), sodium nitroprusside (SNP, 0.05 M; 20, 40, 100 nA), phenylephrine (PE, 0.05 M; 20, 40, 100 nA). Finally, adenosine (ADO, 10-4 M) was superfused over the tissue to identify maximum diameter. In situ vessel reactivity after exposure was significantly blunted based on estrous stage, but not at late-stage pregnancy. Local uterine venular leukocyte trafficking and systemic inflammatory markers were also significantly affected during preparatory (proestrus), fertile (estrus), and infertile (diestrus) periods after ENM inhalation. Overall, these deficits in reactivity and increased inflammatory activity may impair female fertility after ENM exposure.

Maternal engineered nanomaterial inhalation during gestation alters the fetal transcriptome.

BACKGROUND: The integration of engineered nanomaterials (ENM) is well-established and widespread in clinical, commercial, and domestic applications. Cardiovascular dysfunctions have been reported in adult populations after exposure to a variety of ENM. As the diversity of these exposures continues to increase, the fetal ramifications of maternal exposures have yet to be determined. We, and others, have explored the consequences of ENM inhalation during gestation and identified many cardiovascular and metabolic outcomes in the F1 generation. The purpose of these studies was to identify genetic alterations in the F1 generation of Sprague-Dawley rats that result from maternal ENM inhalation during gestation. Pregnant dams were exposed to nano-titanium dioxide (nano-TiO2) aerosols (10 ± 0.5 mg/m3) for 7-8 days (calculated, cumulative lung deposition = 217 ± 1 µg) and on GD (gestational day) 20 fetal hearts were isolated. DNA was extracted and immunoprecipitated with modified chromatin marks histone 3 lysine 4 tri-methylation (H3K4me3) and histone 3 lysine 27 tri-methylation (H3K27me3). Following chromatin immunoprecipitation (ChIP), DNA fragments were sequenced. RNA from fetal hearts was purified and prepared for RNA sequencing and transcriptomic analysis. Ingenuity Pathway Analysis (IPA) was then used to identify pathways most modified by gestational ENM exposure. RESULTS: The results of the sequencing experiments provide initial evidence that significant epigenetic and transcriptomic changes occur in the cardiac tissue of maternal nano-TiO2 exposed progeny. The most notable alterations in major biologic systems included immune adaptation and organismal growth. Changes in normal physiology were linked with other tissues, including liver and kidneys. CONCLUSIONS: These results are the first evidence that maternal ENM inhalation impacts the fetal epigenome.

Inhalation exposure to three-dimensional printer emissions stimulates acute hypertension and microvascular dysfunction.

Fused deposition modeling (FDM™), or three-dimensional (3D) printing has become routine in industrial, occupational and domestic environments. We have recently reported that 3D printing emissions (3DPE) are complex mixtures, with a large ultrafine particulate matter component. Additionally, we and others have reported that inhalation of xenobiotic particles in this size range is associated with an array of cardiovascular dysfunctions. Sprague-Dawley rats were exposed to 3DPE aerosols via nose-only exposure for ~3h. Twenty-four hours later, intravital microscopy was performed to assess microvascular function in the spinotrapezius muscle. Endothelium-dependent and -independent arteriolar dilation were stimulated by local microiontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP). At the time of experiments, animals exposed to 3DPE inhalation presented with a mean arterial pressure of 125±4mmHg, and this was significantly higher than that for the sham-control group (94±3mmHg). Consistent with this pressor response in the 3DPE group, was an elevation of ~12% in resting arteriolar tone. Endothelium-dependent arteriolar dilation was significantly impaired after 3DPE inhalation across all iontophoretic ejection currents (0-27±15%, compared to sham-control: 15-120±21%). Endothelium-independent dilation was not affected by 3DPE inhalation. These alterations in peripheral microvascular resistance and reactivity are consistent with elevations in arterial pressure that follow 3DPE inhalation. Future studies must identify the specific toxicants generated by FDM™ that drive this acute pressor response.