Maternal Engineered Nanomaterial Inhalation During Gestation Disrupts Vascular Kisspeptin Reactivity.

Maternal engineered nanomaterial (ENM) inhalation is associated with uterine vascular impairments and endocrine disruption that may lead to altered gestational outcomes. We have shown that nano-titanium dioxide (nano-TiO2) inhalation impairs endothelium-dependent uterine arteriolar dilation in pregnant rats. However, the mechanism underlying this dysfunction is unknown. Due to its role as a potent vasoconstrictor and essential reproductive hormone, we examined how kisspeptin is involved in nano-TiO2-induced vascular dysfunction and placental efficiency. Pregnant Sprague Dawley rats were exposed (gestational day [GD] 10) to nano-TiO2 aerosols (cumulative dose = 525 ± 16 µg; n = 8) or sham exposed (n = 6) and sacrificed on GD 20. Plasma was collected to evaluate estrogen (E2), progesterone (P4), prolactin (PRL), corticosterone (CORT), and kisspeptin. Pup and placental weights were measured to calculate placental efficiency (grams fetus/gram placental). Additionally, pressure myography was used to determine uterine artery vascular reactivity. Contractile responses were assessed via cumulative additions of kisspeptin (1 × 10-9 to 1 × 10-4 M). Estrogen was decreased at GD 20 in exposed (11.08 ± 3 pg/ml) versus sham-control rats (66.97 ± 3 pg/ml), whereas there were no differences in P4, PRL, CORT, or kisspeptin. Placental weights were increased in exposed (0.99 ± 0.03 g) versus sham-control rats (0.70 ± 0.04 g), whereas pup weights (4.01 ± 0.47 g vs 4.15 ± 0.15 g) and placental efficiency (4.5 ± 0.2 vs 6.4 ± 0.5) were decreased in exposed rats. Maternal ENM inhalation exposure augmented uterine artery vasoconstrictor responses to kisspeptin (91.2%±2.0 vs 98.6%±0.10). These studies represent initial evidence that pulmonary maternal ENM exposure perturbs the normal gestational endocrine vascular axis via a kisspeptin-dependent mechanism, and decreased placental, which may adversely affect health outcomes.

miRNA-378a as a key regulator of cardiovascular health following engineered nanomaterial inhalation exposure.

Nano-titanium dioxide (nano-TiO2), though one of the most utilized and produced engineered nanomaterials (ENMs), diminishes cardiovascular function through dysregulation of metabolism and mitochondrial bioenergetics following inhalation exposure. The molecular mechanisms governing this cardiac dysfunction remain largely unknown. The purpose of this study was to elucidate molecular mediators that connect nano-TiO2 exposure with impaired cardiac function. Specifically, we were interested in the role of microRNA (miRNA) expression in the resulting dysfunction. Not only are miRNA global regulators of gene expression, but also miRNA-based therapeutics provide a realistic treatment modality. Wild type and MiRNA-378a knockout mice were exposed to nano-TiO2 with an aerodynamic diameter of 182 ± 1.70 nm and a mass concentration of 11.09 mg/m3 for 4 h. Cardiac function, utilizing the Vevo 2100 Imaging System, electron transport chain complex activities, and mitochondrial respiration assessed cardiac and mitochondrial function. Immunoblotting and qPCR examined molecular targets of miRNA-378a. MiRNA-378a-3p expression was increased 48 h post inhalation exposure to nano-TiO2. Knockout of miRNA-378a preserved cardiac function following exposure as revealed by preserved E/A ratio and E/SR ratio. In knockout animals, complex I, III, and IV activities (∼2- to 6-fold) and fatty acid respiration (∼5-fold) were significantly increased. MiRNA-378a regulated proteins involved in mitochondrial fusion, transcription, and fatty acid metabolism. MiRNA-378a-3p acts as a negative regulator of mitochondrial metabolic and biogenesis pathways. MiRNA-378a knockout animals provide a protective effect against nano-TiO2 inhalation exposure by altering mitochondrial structure and function. This is the first study to manipulate a miRNA to attenuate the effects of ENM exposure.

Maternal titanium dioxide nanomaterial inhalation exposure compromises placental hemodynamics.

The fetal consequences of gestational engineered nanomaterial (ENM) exposure are unclear. The placenta is a barrier protecting the fetus and allowing transfer of substances from the maternal circulation. The purpose of this study was to determine the effects of maternal pulmonary titanium dioxide nanoparticle (nano-TiO2) exposure on the placenta and umbilical vascular reactivity. We hypothesized that pulmonary nano-TiO2 inhalation exposure increases placental vascular resistance and impairs umbilical vascular responsiveness. Pregnant Sprague-Dawley rats were exposed via whole-body inhalation to nano-TiO2 with an aerodynamic diameter of 188 ±â€¯0.36 nm. On gestational day (GD) 11, rats began inhalation exposures (6 h/exposure). Daily lung deposition was 87.5 ±â€¯2.7 µg. Animals were exposed for 6 days for a cumulative lung burden of 525 ±â€¯16 µg. On GD 20, placentas, umbilical artery and vein were isolated, cannulated, and treated with acetylcholine (ACh), angiotensin II (ANGII), S-nitroso-N-acetyl-DL-penicillamine (SNAP), or calcium-free superfusate (Ca2+-free). Mean outflow pressure was measured in placental units. ACh increased outflow pressure to 53 ±â€¯5 mmHg in sham-controls but only to 35 ±â€¯4 mmHg in exposed subjects. ANGII decreased outflow pressure in placentas from exposed animals (17 ±â€¯7 mmHg) compared to sham-controls (31 ±â€¯6 mmHg). Ca2+-free superfusate yielded maximal outflow pressures in sham-control (63 ±â€¯5 mmHg) and exposed (30 ±â€¯10 mmHg) rats. Umbilical artery endothelium-dependent dilation was decreased in nano-TiO2 exposed fetuses (30 ±â€¯9%) compared to sham-controls (58 ±â€¯6%), but ANGII sensitivity was increased (-79 ±â€¯20% vs -36 ±â€¯10%). These results indicate that maternal gestational pulmonary nano-TiO2 exposure increases placental vascular resistance and impairs umbilical vascular reactivity.

Heterogeneous Vascular Bed Responses to Pulmonary Titanium Dioxide Nanoparticle Exposure.

A growing body of research links engineered nanomaterial (ENM) exposure to adverse cardiovascular endpoints. The purpose of this study was to evaluate the impact of ENM exposure on vascular reactivity in discrete segments so that we may determine the most sensitive levels of the vasculature where these negative cardiovascular effects are manifest. We hypothesized that acute nano-TiO2 exposure differentially affects reactivity with a more robust impairment in the microcirculation. Sprague-Dawley rats (8-10 weeks) were exposed to nano-TiO2via intratracheal instillation (20, 100, or 200 µg suspended per 250 µL of vehicle) 24 h prior to vascular assessments. A serial assessment across distinct compartments of the vascular tree was then conducted. Wire myography was used to evaluate macrovascular active tension generation specifically in the thoracic aorta, the femoral artery, and third-order mesenteric arterioles. Pressure myography was used to determine vascular reactivity in fourth- and fifth-order mesenteric arterioles. Vessels were treated with phenylephrine, acetylcholine (ACh), and sodium nitroprusside. Nano-TiO2 exposure decreased endothelium-dependent relaxation in the thoracic aorta and femoral arteries assessed via ACh by 53.96 ± 11.6 and 25.08 ± 6.36%, respectively. Relaxation of third-order mesenteric arterioles was impaired by 100 and 20 µg nano-TiO2 exposures with mean reductions of 50.12 ± 8.7 and 68.28 ± 8.7%. Cholinergic reactivity of fourth- and fifth-order mesenteric arterioles was negatively affected by nano-TiO2 with diminished dilations of 82.86 ± 12.6% after exposure to 200 µg nano-TiO2, 42.6 ± 12.6% after 100 µg nano-TiO2, and 49.4 ± 12.6% after 20 µg nano-TiO2. Endothelium-independent relaxation was impaired in the thoracic aorta by 34.05 ± 25% induced by exposure to 200 µg nano-TiO2 and a reduction in response of 49.31 ± 25% caused by 100 µg nano-TiO2. Femoral artery response was reduced by 18 ± 5%, while third-order mesenteric arterioles were negatively affected by 20 µg nano-TiO2 with a mean decrease in response of 38.37 ± 10%. This is the first study to directly compare the differential effect of ENM exposure on discrete anatomical segments of the vascular tree. Pulmonary ENM exposure produced macrovascular and microvascular dysfunction resulting in impaired responses to endothelium-dependent, endothelium-independent, and adrenergic agonists with a more robust dysfunction at the microvascular level. These results provide additional evidence of an endothelium-dependent and endothelium-independent impairment in vascular reactivity.

Maternal-engineered nanomaterial exposure disrupts progeny cardiac function and bioenergetics.

Nanomaterial production is expanding as new industrial and consumer applications are introduced. Nevertheless, the impacts of exposure to these compounds are not fully realized. The present study was designed to determine whether gestational nano-sized titanium dioxide exposure impacts cardiac and metabolic function of developing progeny. Pregnant Sprague-Dawley rats were exposed to nano-aerosols (~10 mg/m3, 130- to 150-nm count median aerodynamic diameter) for 7-8 nonconsecutive days, beginning at gestational day 5-6 Physiological and bioenergetic effects on heart function and cardiomyocytes across three time points, fetal (gestational day 20), neonatal (4-10 days), and young adult (6-12 wk), were evaluated. Functional analysis utilizing echocardiography, speckle-tracking based strain, and cardiomyocyte contractility, coupled with mitochondrial energetics, revealed effects of nano-exposure. Maternal exposed progeny demonstrated a decrease in E- and A-wave velocities, with a 15% higher E-to-A ratio than controls. Myocytes isolated from exposed animals exhibited ~30% decrease in total contractility, departure velocity, and area of contraction. Bioenergetic analysis revealed a significant increase in proton leak across all ages, accompanied by decreases in metabolic function, including basal respiration, maximal respiration, and spare capacity. Finally, electron transport chain complex I and IV activities were negatively impacted in the exposed group, which may be linked to a metabolic shift. Molecular data suggest that an increase in fatty acid metabolism, uncoupling, and cellular stress proteins may be associated with functional deficits of the heart. In conclusion, gestational nano-exposure significantly impairs the functional capabilities of the heart through cardiomyocyte impairment, which is associated with mitochondrial dysfunction.NEW & NOTEWORTHY Cardiac function is evaluated, for the first time, in progeny following maternal nanomaterial inhalation. The findings indicate that exposure to nano-sized titanium dioxide (nano-TiO2) during gestation negatively impacts cardiac function and mitochondrial respiration and bioenergetics. We conclude that maternal nano-TiO2 inhalation contributes to adverse cardiovascular health effects, lasting into adulthood.

Metal Nanomaterial Toxicity Variations Within the Vascular System.

Engineered nanomaterials (ENM) are anthropogenic materials with at least one dimension less than 100 nm. Their ubiquitous employment in biomedical and industrial applications in the absence of full toxicological assessments raises significant concerns over their safety on human health. This is a significant concern, especially for metal and metal oxide ENM as they may possess the greatest potential to impair human health. A large body of literature has developed that reflects adverse systemic effects associated with exposure to these materials, but an integrated mechanistic framework for how ENM exposure influences morbidity remains elusive. This may be due in large part to the tremendous diversity of existing ENM and the rate at which novel ENM are produced. In this review, the influence of specific ENM physicochemical characteristics and hemodynamic factors on cardiovascular toxicity is discussed. Additionally, the toxicity of metallic and metal oxide ENM is presented in the context of the cardiovascular system and its discrete anatomical and functional components. Finally, future directions and understudied topics are presented. While it is clear that the nanotechnology boom has increased our interest in ENM toxicity, it is also evident that the field of cardiovascular nanotoxicology remains in its infancy and continued, expansive research is necessary in order to determine the mechanisms via which ENM exposure contributes to cardiovascular morbidity.

Xenobiotic pulmonary exposure and systemic cardiovascular response via neurological links.

The cardiovascular response to xenobiotic particle exposure has been increasingly studied over the last two decades, producing an extraordinary scope and depth of research findings. With the flourishing of nanotechnology, the term "xenobiotic particles" has expanded to encompass not only air pollution particulate matter (PM) but also anthropogenic particles, such as engineered nanomaterials (ENMs). Historically, the majority of research in these fields has focused on pulmonary exposure and the adverse physiological effects associated with a host inflammatory response or direct particle-tissue interactions. Because these hypotheses can neither account entirely for the deleterious cardiovascular effects of xenobiotic particle exposure nor their time course, the case for substantial neurological involvement is apparent. Indeed, considerable evidence suggests that not only is neural involvement a significant contributor but also a reality that needs to be investigated more thoroughly when assessing xenobiotic particle toxicities. Therefore, the scope of this review is several-fold. First, we provide a brief overview of the major anatomical components of the central and peripheral nervous systems, giving consideration to the potential biologic targets affected by inhaled particles. Second, the autonomic arcs and mechanisms that may be involved are reviewed. Third, the cardiovascular outcomes following neurological responses are discussed. Lastly, unique problems, future risks, and hurdles associated with xenobiotic particle exposure are discussed. A better understanding of these neural issues may facilitate research that in conjunction with existing research, will ultimately prevent the untoward cardiovascular outcomes associated with PM exposures and/or identify safe ENMs for the advancement of human health.

Platelet-rich preparations to improve healing. Part I: workable options for every size practice.

Numerous studies have demonstrated that platelet-rich preparations applied to surgical sites, injuries, or wounds are a safe and effective way to promote soft tissue healing and bone growth. Various protocols have been developed for preparing platelet-rich preparations, with subtle but important differences between them. Unfortunately, only a minority of clinicians use platelet-rich preparations, such as platelet-rich plasma and platelet-rich fibrin, in their practice, possibly due to confusion about the different methods and their advantages and disadvantages. Therefore, the different types of preparations are described to help guide the selection of the best method for any size practice. Classic methods generally require large volumes of blood and can be expensive, complicated, and time-intensive. Simpler protocols have been developed recently, which require relatively inexpensive equipment and small blood volumes and, thus, may be more applicable for small clinical practices. Platelet-rich preparations accelerate healing at earlier time points to reduce discomfort and the potential for adverse outcomes, including infection, poor wound closure, and delays in forming strong bone for subsequent procedures (such as implants). However, platelet-rich preparations may also improve long-term outcomes in patients expected to have impaired healing, such as with lifestyle choices (eg, smoking), medications (eg, steroids), diseases (eg, diabetes, osteoporosis, atherosclerosis), and aging, by supplementing the deficient wound environment to restore proper healing. Therefore, both large and small clinical practices would benefit from utilizing platelet-rich preparations to enhance healing in their patients.

Platelet-rich preparations to improve healing. Part II: platelet activation and enrichment, leukocyte inclusion, and other selection criteria.

Multiple platelet-rich preparations have been reported to improve wound and bone healing, such as platelet-rich plasma (PRP) and platelet rich fibrin (PRF). The different methods employed during their preparation are important, as they influence the quality of the product applied to a wound or surgical site. Besides the general protocol for preparing the platelet-rich product (discussed in Part 1 of this review), multiple choices need to be considered during its preparation. For example, activation of the platelets is required for the release and enmeshment of growth factors, but the method of activation may influence the resulting matrix, growth factor availability, and healing. Additionally, some methods enrich leukocytes as well as platelets, but others are designed to be leukocyte-poor. Leukocytes have many important roles in healing and their inclusion in PRP results in increased platelet concentrations. Platelet and growth factor enrichment reported for the different types of platelet-rich preparations are also compared. Generally, TGF-ß1 and PDGF levels were higher in preparations that contain leukocytes compared to leukocyte-poor PRP. However, platelet concentration may be the most reliable criterion for comparing different preparations. These and other criteria are described to help guide dental and medical professionals, in large and small practices, in selecting the best procedures for their patients. The healing benefits of platelet-rich preparations along with the low risk and availability of simple preparation procedures should encourage more clinicians to incorporate platelet-rich products in their practice to accelerate healing, reduce adverse events, and improve patient outcomes.