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Aged spontaneously hypertensive rats (SHRs) are predisposed to ultrafine carbon particle (UfCP) mediated cardiovascular impairment.
Citation:
Upadhyay, S., K. Ganguly, T. Stoeger, L. George, M. Schladweiler, U. Kodavanti, AND H. Schulz. Aged spontaneously hypertensive rats (SHRs) are predisposed to ultrafine carbon particle (UfCP) mediated cardiovascular impairment. European Respiratory Society, Munich, GERMANY, September 06 - 10, 2014.
Impact/Purpose:
This collaborative research shows that hypertensive rats with advanced age are more susceptible to coagulatory and cardiovascular effects of carbon nano particles when compared to relatively young hypertensive rats.
Description:
Background: Elderly individuals are considered to be more susceptible to particulate matter (PM) related cardiovascular (CV) health effects. In this study we investigated UfCP mediated CV effects on aged SHRs and compared the findings to that of adult SHRs to identify age related pathomechanisms. Methods: SHRs were exposed by inhalation to UfC P for 24h (~180 ug/m3). Blood pressure (BP) and heart rate (HR) was measured radio-telemetrically. Bronchoalveolar lavage (BAL) fluid cell differentials, proinflammatory cytokines, serum C-reactive protein (CRP) and haptoglobin (HPT), and plasma fibrinogen were measured. Hemeoxygenase 1 (HO-1), endothelin 1 (ET1), endothelin receptors A and B (ETA and ETB),tissue factor (TF), plasminogen activator inhibitor-1 (PAI-1) transcripts were assessed in lung and heart. Result: UfCP exposed aged SHRs exhibited increased BP (4.4%) and HR (6.3%) on 1st recovery day. This paralleled with increased neutrophils and IL-6 in the BAL fluid. Simultaneously increased serum CRP, HPT and fibrinogen levels indicate systemic inflammation. HO-1, ET1, ET-A, ET-B, TF and PAI-1 were induced by 1.5-2.0 folds in the lung of exposed SHRs on 1st recovery day. However, in adult SHRs all of those markers were up-regulated by 2.5 fold on 3rd recovery day except ET-1 which induced 6.0 folds in pulmonary tissue following UfC Ps exposure.Conclusions: UfCP exposure increased BP and HR in both, adult and aged SHRs rats but pulmonary and systemic inflammation with disturbed coagulatory hemostasis was only found in aged SHRs. Thus, advanced age and preexisting hypertension are associated with increased risk of PM mediated CV health effects. (Does not reflect USEPA policy).