Histopathology and pathogenesis of caerulein-, duct ligation-, and arginine-induced acute pancreatitis in Sprague-Dawley rats and C57BL6 mice.

Three classical rodent models of acute pancreatitis were created in an effort to identify potential pre-clinical models of drug-induced pancreatitis (DIP) and candidate non-invasive biomarkers for improved detection of DIP. Study objectives included designing a lexicon to minimize bias by capturing normal variation and spontaneous and injury-induced changes while maintaining the ability to statistically differentiate degrees of change, defining morphologic anchors for novel pancreatic injury biomarkers, and improved understanding of mechanisms responsible for pancreatitis. Models were created in male Sprague-Dawley rats and C57BL6 mice through: 1) administration of the cholecystokinin analog, caerulein; 2) administration of arginine; 3) surgical ligation of the pancreatic duct. Nine morphologically detectable processes were used in the lexicon; acinar cell hypertrophy; acinar cell autophagy; acinar cell apoptosis; acinar cell necrosis; vascular injury; interstitial edema, inflammation and hemorrhage; fat necrosis; ductal changes; acinar cell atrophy. Criteria were defined for scoring levels (0 = absent, 1 = mild, 2 = moderate, 3 = severe) for each lexicon component. Consistent with previous studies, histopathology scores were significant greater in rats compared to mice at baseline and after treatment. The histopathology scores in caerulein and ligation-treated rats and mice were significantly greater than those of arginine-treated rats and mice. The present study supports a multifaceted pathogenesis for acute pancreatitis in which intra-acinar trypsinogen activation, damage to acinar cells, fat cells, and vascular cells as well as activation/degranulation of mast cells and activated macrophages all contribute to the initiation and/or progression of acute inflammation of the exocrine pancreas.

In utero exposure to second-hand smoke aggravates the response to ovalbumin in adult mice.

Second-hand smoke (SHS) exposure in utero exacerbates adult responses to environmental irritants. We tested the hypothesis that effects of in utero SHS exposure on modulating physiological and transcriptome responses in BALB/c mouse lungs after ovalbumin (OVA) challenge extend well into adulthood, and that the responses show a sex bias. We exposed BALB/c mice in utero to SHS or filtered air (AIR), then sensitized and challenged all offspring with OVA from 19 to 23 weeks of age. At the end of the adult OVA challenge, we evaluated pulmonary function, examined histopathology, analyzed bronchoalveolar lavage fluid (BALF), and assessed gene expression changes in the lung samples. All groups exhibited lung inflammation and inflammatory cell infiltration. Pulmonary function testing (airway hyperresponsiveness [AHR], breathing frequency [f]) and BALF (cell differentials, Th1/Th2 cytokines) assessments showed significantly more pronounced lung responses in the SHS-OVA groups than in AIR-OVA groups (AHR, f; eosinophils, neutrophils; IFN-γ, IL-1b, IL-4, IL-5, IL-10, IL-13, KC/CXCL1, TNF-α), with the majority of responses being more pronounced in males than in females. SHS exposure in utero also significantly altered lung gene expression profiles, primarily of genes associated with inflammatory responses and respiratory diseases, including lung cancer and lung fibrosis. Altered expression profiles of chemokines (Cxcl2, Cxcl5, Ccl8, Ccl24), cytokines (Il1b, Il6, Il13) and acute phase response genes (Saa1, Saa3) were confirmed by qRT-PCR. In conclusion, in utero exposure to SHS exacerbates adult lung responses to OVA challenge and promotes a pro-asthmatic milieu in adult lungs; further, males are generally more affected by SHS-OVA than are females.

Kidney injury biomarkers in hypertensive, diabetic, and nephropathy rat models treated with contrast media.

Contrast-induced nephropathy (CIN) refers to a decline in renal function following exposure to iodinated contrast media (CM). The present study was initiated to explore the role of known human risk factors (spontaneous hypertension, diabetes, protein-losing nephropathy) on CIN development in rodent models and to determine the effect of CM administration on kidney injury biomarkers in the face of preexisting kidney injury. Spontaneously hypertensive rats (hypertension), streptozotocin-treated Sprague Dawley rats (diabetes), and Dahl salt-sensitive rats (protein-losing nephropathy) were given single intravenous injections of the nonionic, low osmolar contrast medium, iohexol. Blood urea nitrogen (BUN), serum creatinine (sCr), and urinary biomarkers; albumin, lipocalin 2 (Lcn-2), osteopontin (Opn), kidney injury molecule 1 (Kim-1), renal papillary antigen 1 (Rpa-1), α-glutathione S-transferase (α-Gst), µ-glutathione S-transferase (µ-Gst), and beta-2 microglobulin (ß2m) were measured in disease models and appropriate controls to determine the response of these biomarkers to CM administration. Each disease model produced elevated biomarkers of kidney injury without CM. Preexisting histopathology was exacerbated by CM but little or no significant increases in biomarkers were observed. When 1.5-fold or greater sCr increases from pre-CM were used to define true positives, receiver-operating characteristic curve analysis of biomarker performance showed sCr was the best predictor of CIN across disease models. ß2m, Lcn-2, and BUN were the best predictors of histopathology defined kidney injury.

Oleic acid and glucose regulate glucagon-like peptide 1 receptor expression in a rat pancreatic ductal cell line.

The glucagon-like peptide 1 receptor (GLP1R) plays a critical role in glucose metabolism and has become an important target for a growing class of drugs designed to treat type 2 diabetes. In vitro studies were designed to investigate the effect of the GLP1R agonist, exenatide (Ex4), in "on-target" RIN-5mF (islet) cells as well as in "off-target" AR42J (acinar) and DSL-6A/C1 (ductal) cells in a diabetic environment. Ex4 increased islet cell proliferation but did not affect acinar cells or ductal cells at relevant concentrations. A high caloric, high fat diet is a risk factor for impaired glucose tolerance and type-2 diabetes. An in vitro Oleic acid (OA) model was used to investigate the effect of Ex4 in a high calorie, high fat environment. At 0.1 and 0.4mM, OA mildly decreased the proliferation of all pancreatic cell types. Ex4 did not potentiate the inhibitory effect of OA on cell proliferation. Akt phosphorylation in response to Ex4 was diminished in OA-treated ductal cells. GLP1R protein detected by western blot was time and concentration dependently decreased after glucose stimulation in OA-treated ductal cells. In ductal cells, OA treatment altered the intracellular localization of GLP1R and its co-localization with early endosome and recycling endosomes. Chloroquine (lysosomal inhibitor), N-acetyl-l-cysteine (reactive oxygen species scavenger) and wortmannin (a phosphatidylinositol-3-kinase inhibitor), fully or partially, rescued GLP1R protein in OA-pretreated, glucose-stimulated ductal cells. The impact of altered regulation on phenotype/function is presently unknown. However, these data suggest that GLP1R regulation in ductal cells can be altered by a high fat, high calorie environment.

Comparative profile of commercially available urinary biomarkers in preclinical drug-induced kidney injury and recovery in rats.

We designed a study to provide reversibility and comparative injury data for several candidate urinary biomarkers of kidney injury in the United States Food and Drug Administration biomarker qualification process. The nephrotoxin gentamicin was given to rats once on each of three days and the animals were killed during dosing or over the following 42 days. Between days one and three, all biomarkers except albumin were elevated, peaked at day 7, and returned to control levels by day 10 (µ- and α-glutathione S-transferases, and renal papillary antigen-1) or day 15 (kidney injury molecule-1, lipocalin-2, osteopontin, and clusterin). All biomarkers performed better during injury than during recovery except osteopontin, which performed equally well in both time periods. During the evolution of injury, kidney injury molecule-1, renal papillary antigen-1, and clusterin best mirrored the histopathologic lesions. During injury resolution, kidney injury molecule-1, osteopontin, and blood urea nitrogen best reflected recovery. Based on histopathology, necrosis, or apoptosis scoring, kidney injury molecule-1 was the best biomarker of overall renal injury. Evaluation by regeneration score showed that renal papillary antigen-1 best reflected tubular and/or collecting duct regeneration, especially during recovery. Thus, these biomarkers performed with different effectiveness when evaluated by individual pathological processes such as necrosis, apoptosis, and regeneration.

Soot nanoparticles promote biotransformation, oxidative stress, and inflammation in murine lungs.

We previously described the physicochemical characteristics (particle size, adsorbed polynuclear aromatic hydrocarbons [PAHs], oxygen, and metal content) of butadiene soot (BDS) nanoparticles generated during incomplete combustion of the high-volume industrial petrochemical, 1,3-butadiene. We also demonstrated localization of BDS-delivered PAHs to lipid droplets of murine and human respiratory cells in vitro and up-regulation of biotransformation and oxidative stress responses in these cells. Here, the objective was to determine whether inhalation of BDS nanoparticles promotes up-regulation of Phase I biotransformation enzymes, oxidative stress responses, and inflammation in the lungs of mice. Female Balb/c mice exposed to BDS (5 mg/m(3), 4 h/d, 4 d) were killed immediately or 1 day after final exposure; bronchoalveolar lavage fluid (BALF) was collected from the lungs; total RNA was extracted from one lung and histopathology performed on the other. Histopathology and BALF analysis revealed particle-laden macrophages in airways of BDS-treated mice, accompanied by neutrophilia and epithelial damage. Microarray and qRT-PCR analyses revealed up-regulation of (1) aryl hydrocarbon receptor (AhR)-responsive genes: AhR repressor (Ahrr) and cytochrome P450 IA1 and IB1(Cyp1a1, Cyp1b1); (2) oxidative stress response genes: heme oxygenase 1 (Hmox1), nuclear factor erythroid-derived 2-like 2 (Nfe2l2), NADPH dehydrogenase quinone 1 (Nqo1), and glutathione peroxidase 2 (Gpx2); and (3) pro-inflammatory genes: interleukin-6 (IL-6), C-X-C motif ligand 2 (Cxcl2; analog to human IL-8) and ligand 3 (Cxcl3), and granulocyte chemotactic protein (Cxcl6). Inhalation of PAH-rich, petrochemical combustion-derived nanoparticles causes airway inflammation and induces expression of AhR-associated and oxidative stress response genes, as seen in vitro, plus pro-inflammatory genes.

Combustion-derived hydrocarbons localize to lipid droplets in respiratory cells.

Combustion-generated radicals interact to form polynuclear aromatic hydrocarbons (PAHs), including carcinogens. PAHs aggregate into 20- to 50-nm particles, which extend into branched-chain structures (soots). Incomplete combustion yields black soot particles and black smoke. Many PAHs, including those in soots, fluoresce upon excitation. We have reported that butadiene soot (BDS), generated during combustion of the high-volume petrochemical 1,3-butadiene, serves as a reproducible example of combustion-derived fine and ultrafine particles, with the potential for acute or delayed health effects. Human bronchoepithelial cells (BEAS-2B) display time- and concentration-dependent responses to BDS exposure, culminating in concentration of fluorescent PAHs within discrete cytoplasmic bodies. Here we identify the cytoplasmic compartment(s) in which combustion-derived PAHs concentrate and assess the metabolic responses associated with this compartmentalization. BDS-associated fluorescence colocalized with a red fluorescent cholesterol analog and a transfected plasmid coding for a fluorescent lipid droplet surface protein within BEAS-2B cells. After BDS exposure, murine alveolar macrophages (MH-S) and adipocytes (3T3-L1) also develop fluorescence. These findings, especially within adipocytes, support the accumulation of PAHs within lipid droplets. Microarray data revealed up-regulation of aryl hydrocarbon receptor-induced Phase I biotransformation enzymes and nuclear erythroid-2 related factor 2-mediated oxidative stress responses in BEAS-2B cells. Quantitative RT-PCR results confirmed a time-dependent up-regulation of Phase I biotransformation enzymes (CYP1A1, CYP1B1, and ALDH3A1) in BDS-exposed BEAS-2B and MH-S cells. Thus, respiratory cell lipid droplets concentrate PAHs delivered by combustion-derived ultrafine particles. These PAHs, including several found in BDS and in cigarette smoke, activate xenobiotic metabolism pathways and thereby potentiate their toxicity.

In utero environmental tobacco smoke exposure alters gene expression in lungs of adult BALB/c mice.

BACKGROUND: In utero environmental tobacco smoke (ETS) exposure exacerbates initial lung responses of adult mice to ovalbumin (OVA), a common allergen in rodent models of allergic asthma. OBJECTIVE: We tested the hypothesis that in utero ETS exposure alters expression of genes (including asthma-related and inflammatory genes) in the lungs of adult mice and that this differential expression is reflected in differential respiratory and immune responses to nontobacco allergens. METHODS: Using Affymetrix Mouse Genome 430 2.0 arrays, we examined gene expression changes in lungs of BALB/c mice exposed to ETS in utero, OVA, or saline aerosol at weeks 7-8, and OVA sensitization and challenge at weeks 11-15. Data sets were filtered by transcript p-value (< or = 0.05), false discovery rate (< or = 0.05), and fold change (> or = 1.5). Differential expression of selected genes was confirmed by polymerase chain reaction (PCR). RESULTS: Genes differentially expressed as a result of in utero ETS exposure are involved in regulation of biological processes (immune response, cell proliferation, apoptosis, cell metabolism) through altered cytoskeleton, adhesion, transcription, and enzyme molecules. A number of genes prominent in lung inflammation were differentially expressed on PCR but did not pass selection criteria for microarray, including arginase (Arg1), chitinases (Chia, Chi3l3, Chi3l4), eotaxins (Ccl11, Ccl24), small proline-rich protein 2a (Sprr2a), and cytokines (Il4, Il6, Il10, Il13, Tnfa) . CONCLUSION: The differential lung gene expression reported here is consistent with previously reported functional changes in lungs of mice exposed in utero to ETS and as adults to the nontobacco allergen OVA.

In utero exposure to environmental tobacco smoke potentiates adult responses to allergen in BALB/c mice.

BACKGROUND: Fetal stress has been linked to adult atherosclerosis, obesity, and diabetes. Epidemiology studies have associated fetal exposure to maternal smoking and postnatal exposure to environmental tobacco smoke (ETS) with increased asthma risk. OBJECTIVE: We tested the hypothesis, in a mouse model of asthma, that in utero ETS exposure alters airway function and respiratory immune responses in adults. METHODS: Pregnant Balb/c mice were exposed daily to ETS or HEPA-filtered air (AIR). Offspring inhaled aerosolized ovalbumin (OVA) or saline in weeks 7-8. Regardless of whether they inhaled OVA or saline, mice were sensitized by OVA injections in weeks 11 and 13 followed by OVA aerosol challenge in weeks 14-15. At three time points, we assessed OVA-specific serum immunoglobins, bronchoalveolar lavage cells and cytokines, lung and nasal histopathology, and airway hyperresponsiveness (AHR). RESULTS: At 6 weeks, we found no significant differences between in utero ETS and AIR mice. At 10 weeks, following OVA aerosol, ETS mice displayed greater AHR than AIR mice (alpha = 0.05), unaccompanied by changes in histopathology, cytokine profile, or antibody levels. At 15 weeks, mice that had inhaled saline in weeks 7-8 developed airway inflammation: eosinophilia (alpha = 0.05), interleukin-5 (alpha = 0.05), and AHR (alpha = 0.05) were greater in ETS mice than in AIR mice. Mice that had inhaled OVA in weeks 7-8 demonstrated no airway inflammation after sensitization and challenge. CONCLUSION: In utero ETS exposure exacerbates subsequent adult responses to initial allergen exposure.