Carol Hoffman

Cadmium Associated With Inhaled Cadmium Oxide Nanoparticles Impacts Fetal and Neonatal Development and Growth

One industrially important metal oxide nanoparticle (NP) is cadmium oxide (CdO). A study was performed using timed-pregnant CD-1 mice to determine if Cd associated with inhaled CdO NP could reach the placenta and adversely affect the developing fetus and/or neonate. Pregnant mice were exposed by inhalation either every other day to 100 μg of freshly generated CdO/m(3) (exposure 1) or daily to 230 μg CdO/m(3) (exposure 2). In each exposure, mice were exposed to CdO NP or carrier gas (control) for 2.5 h from 4.5 days post coitus (dpc) through 16.5 dpc. At 17.5 dpc, fetuses and placentas from both exposures 1 and 2 were collected, measured, and weighed. A subgroup from the second exposure was allowed to give birth, and neonates were weighed daily until weaning. Cadmium in the uterus and placenta, as well as in other maternal organs, was elevated in NP-treated mice, but was undetectable in fetuses at 17.5 dpc. Daily inhalation of 230 μg CdO NP/m(3) decreased the incidence of pregnancy (i.e., no evidence of implantation) by 23%, delayed maternal weight gain, altered placental weight, and decreased fetal length, as well as delayed neonatal growth. This study demonstrates that inhalation of CdO NP during pregnancy adversely affects reproductive fecundity and alters fetal and postnatal growth of the developing offspring.

Prenatal cigarette smoke exposure causes hyperactivity and aggressive behavior: role of altered catecholamines and BDNF.

Smoking during pregnancy is associated with a variety of untoward effects on the offspring. However, recent epidemiological studies have brought into question whether the association between neurobehavioral deficits and maternal smoking is causal. We utilized an animal model of maternal smoking to determine the effects of prenatal cigarette smoke (CS) exposure on neurobehavioral development. Pregnant mice were exposed to either filtered air or mainstream CS from gestation day (GD) 4 to parturition for 4h/d and 5d/wk, with each exposure producing maternal plasma concentration of cotinine equivalent to smoking <1 pack of cigarettes per day (25ng/ml plasma cotinine level). Pups were weaned at postnatal day (PND) 21 and behavior was assessed at 4weeks of age and again at 4-6months of age. Male, but not female, offspring of CS-exposed dams demonstrated a significant increase in locomotor activity during adolescence and adulthood that was ameliorated by methylphenidate treatment. Additionally, male offspring exhibited increased aggression, as evidenced by decreased latency to attack and number of attacks in a resident-intruder task. These behavioral abnormalities were accompanied by a significant decrease in striatal and cortical dopamine and serotonin and a significant reduction in brain-derived neurotrophic factor (BDNF) mRNA and protein. Taken in concert, these data demonstrate that prenatal exposure to CS produces behavioral alterations in mice that are similar to those observed in epidemiological studies linking maternal smoking to neurodevelopmental disorders. Further, these data also suggest a role for monaminergic and BDNF alterations in these effects.

Prenatal and Early-Life Exposure to High-Level Diesel Exhaust Particles Leads to Increased Locomotor Activity and Repetitive Behaviors in Mice

Abundant evidence indicates that both genetic and environmental factors contribute to the etiology of autism spectrum disorders (ASDs). However, limited knowledge is available concerning these contributing factors. An epidemiology study reported a link between increased incidence of autism and living closely to major highways, suggesting a possible role for pollutants from highway traffic. We investigated whether maternal exposure to diesel exhaust particles (DEP) negatively affects fetal development leading to autism‐like phenotype in mice. Female mice and their offspring were exposed to DEP during pregnancy and nursing. Adult male offspring were then tested for behaviors reflecting the typical symptoms of ASD patients. Compared to control mice, DEP‐exposed offspring exhibited higher locomotor activity, elevated levels of self‐grooming in the presence of an unfamiliar mouse, and increased rearing behaviors, which may be relevant to the restricted and repetitive behaviors seen in ASD patients. However, the DEP‐exposed mice did not exhibit deficits in social interactions or social communication which are the key features of ASD. These results suggest that early life exposure to DEP could have an impact on mouse development leading to observable changes in animal behaviors. Further studies are needed to reveal other environmental insults and genetic factors that would lead to animal models expressing key phenotypes of the autism spectrum disorders. Autism Res 2013, ●●: ●●–●●.

Modification of Hemodynamic and Immune Responses to Exposure with a Weak Antigen by the Expression of a Hypomorphic BMPR2 Gene

Background Hypomorphic mutations in the bone morphogenic protein receptor (BMPR2) confer a much greater risk for developing pulmonary arterial hypertension (PAH). However, not all carriers of a mutation in the BMPR2 gene suffer from PAH. We have previously shown that prolonged T helper 2 (Th2) responses in the lungs to a mild antigen delivered via the airways induce severe pulmonary arterial remodeling, but no pulmonary hypertension. The current studies were designed to test the idea that Th2 responses to a mild antigen together with the expression of a hypomorphic BMPR2 gene would trigger pulmonary hypertension. Methodology/Principal Findings Mice that expressed a hypomorphic BMPR2 transgene (transgene-positive) and transgene-negative mice were either exposed to saline, or primed and exposed to a mild antigen (Ovalbumin) over a prolonged period of time. Only transgene-positive but not transgene-negative mice exposed to antigen developed significantly increased right ventricular systolic pressures, while both groups showed pulmonary artery remodeling with severe muscularization and airway inflammation to a similar degree. Antigen exposure resulted in a smaller increase in the percentage of Interleukin (IL)-13 positive T cells in the lymph nodes, and in a smaller increase in resistin-like-molecule (RELM)α expression and a decreased ratio of expression of IL-33 relative to its receptor (IL-1-receptor-like 1, IL1RL1-ST2) in the right ventricles of transgene-positive mice compared to transgene-negative animals. Furthermore, only antigen-challenged transgene-positive mice showed a significant increase in Interferon (IFN)γ positive T cells over saline-exposed controls. Conclusions/Significance Our study suggests that exposure with a mild Th2 antigen can trigger pulmonary hypertension on the background of the expression of a hypomorphic BMPR2 gene and that conversely, the expression of the hypomorphic BMPR2 gene can alter the immune response to a mild, inhaled antigen.

Interleukin-19: a constituent of the regulome that controls antigen presenting cells in the lungs and airway responses to microbial products.

Background Interleukin (IL)-19 has been reported to enhance chronic inflammatory diseases such as asthma but the in vivo mechanism is incompletely understood. Because IL-19 is produced by and regulates cells of the monocyte lineage, our studies focused on in vivo responses of CD11c positive (CD11c+) alveolar macrophages and lung dendritic cells. Methodology/Principal Findings IL-19-deficient (IL-19-/-) mice were studied at baseline (naïve) and following intranasal challenge with microbial products, or recombinant cytokines. Naïve IL-19-/- mixed background mice had a decreased percentage of CD11c+ cells in the bronchoalveolar-lavage (BAL) due to the deficiency in IL-19 and a trait inherited from the 129-mouse strain. BAL CD11c+ cells from fully backcrossed IL-19-/- BALB/c or C57BL/6 mice expressed significantly less Major Histocompatibility Complex class II (MHCII) in response to intranasal administration of lipopolysaccharide, Aspergillus antigen, or IL-13, a pro-allergic cytokine. Neurogenic-locus-notch-homolog-protein-2 (Notch2) expression by lung monocytes, the precursors of BAL CD11c+ cells, was dysregulated: extracellular Notch2 was significantly decreased, transmembrane/intracellular Notch2 was significantly increased in IL-19-/- mice relative to wild type. Instillation of recombinant IL-19 increased extracellular Notch2 expression and dendritic cells cultured from bone marrow cells in the presence of IL-19 showed upregulated extracellular Notch2. The CD205 positive subset among the CD11c+ cells was 3-5-fold decreased in the airways and lungs of naïve IL-19-/- mice relative to wild type. Airway inflammation and histological changes in the lungs were ameliorated in IL-19-/- mice challenged with Aspergillus antigen that induces T lymphocyte-dependent allergic inflammation but not in IL-19-/- mice challenged with lipopolysaccharide or IL-13. Conclusions/Significance Because MHCII is the molecular platform that displays peptides to T lymphocytes and Notch2 determines cell fate decisions, our studies suggest that endogenous IL-19 is a constituent of the regulome that controls both processes in vivo.

Right Ventricular Systolic Pressure Measurements in Combination with Harvest of Lung and Immune Tissue Samples in Mice

The function of the right heart is to pump blood through the lungs, thus linking right heart physiology and pulmonary vascular physiology. Inflammation is a common modifier of heart and lung function, by elaborating cellular infiltration, production of cytokines and growth factors, and by initiating remodeling processes. Compared to the left ventricle, the right ventricle is a low-pressure pump that operates in a relatively narrow zone of pressure changes. Increased pulmonary artery pressures are associated with increased pressure in the lung vascular bed and pulmonary hypertension. Pulmonary hypertension is often associated with inflammatory lung diseases, for example chronic obstructive pulmonary disease, or autoimmune diseases. Because pulmonary hypertension confers a bad prognosis for quality of life and life expectancy, much research is directed towards understanding the mechanisms that might be targets for pharmaceutical intervention. The main challenge for the development of effective management tools for pulmonary hypertension remains the complexity of the simultaneous understanding of molecular and cellular changes in the right heart, the lungs and the immune system. Here, we present a procedural workflow for the rapid and precise measurement of pressure changes in the right heart of mice and the simultaneous harvest of samples from heart, lungs and immune tissues. The method is based on the direct catheterization of the right ventricle via the jugular vein in close-chested mice, first developed in the late 1990s as surrogate measure of pressures in the pulmonary artery. The organized team-approach facilitates a very rapid right heart catheterization technique. This makes it possible to perform the measurements in mice that spontaneously breathe room air. The organization of the work-flow in distinct work-areas reduces time delay and opens the possibility to simultaneously perform physiology experiments and harvest immune, heart and lung tissues. The procedural workflow outlined here can be adapted for a wide variety of laboratory settings and study designs, from small, targeted experiments, to large drug screening assays. The simultaneous acquisition of cardiac physiology data that can be expanded to include echocardiography and harvest of heart, lung and immune tissues reduces the number of animals needed to obtain data that move the scientific knowledge basis forward. The procedural workflow presented here also provides an ideal basis for gaining knowledge of the networks that link immune, lung and heart function. The same principles outlined here can be adapted to study other or additional organs as needed.

Toxicity of Gutkha, a Smokeless Tobacco Product Gone Global: Is There More to the Toxicity than Nicotine?

The popularity of smokeless tobacco (ST) is growing rapidly and its prevalence of use is rising globally. Consumption of Gutkha, an addictive form of ST, is particularly common amongst South Asian communities throughout the World. This includes within the US, following large-scale immigration into the country. However, there exists a lack of knowledge concerning these alternative tobacco products. To this end, a study was carried out to determine the toxicity of gutkha, and what role, if any, nicotine contributes to the effects. Adult male mice were treated daily for 3-week (5 day/week, once/day), via the oral mucosa, with equal volumes (50 μL) of either sterile water (control), a solution of nicotine dissolved in water (0.24 mg of nicotine), or a solution of lyophilized guthka dissolved in water (21 mg lyophilized gutkha). Serum cotinine, measured weekly, was 36 and 48 ng/mL in gutkha- and nicotine-treated mice, respectively. Results demonstrated that exposure to nicotine and gutkha reduced heart weight, while exposure to gutkha, but not nicotine, decreased liver weight, body weight, and serum testosterone levels (compared to controls). These findings suggest that short-term guhtka use adversely impacts growth and circulating testosterone levels, and that gutkha toxicity may be driven by components other than nicotine. As use of guthka increases worldwide, future studies are needed to further delineate toxicological implications such that appropriate policy decisions can be made.