Investigation of the Molecular Mechanisms Preceding PDE4 Inhibitor-Induced Vasculopathy in Rats: Tissue Inhibitor of Metalloproteinase 1, a Potential Predictive Biomarker

Abstract

Phosphodiesterase (PDE) 4 inhibitors are a class of drugs that can provide novel therapies for asthma and chronic obstructive pulmonary disease. Their development is frequently hampered by the induction of vascular toxicity in rat mesenteric tissue during preclinical studies. Whereas these vascular lesions in rats have been well characterized histologically, little is known about their pathogenesis and in turn, sensitive and specific biomarkers for preclinical and clinical monitoring do not exist. In order to investigate the early molecular mechanisms underlying vascular injury, time-course studies were performed by treating rats for 2-24 h with high doses of the PDE4 inhibitor CI-1044. Transcriptomics analyses in mesenteric tissue were performed using oligonucleotide microarray and real-time RT-PCR technologies and compared to histopathological observations. In addition, protein measurements were performed in serum samples to identify soluble biomarkers of vascular injury. Our results indicate that molecular alterations preceded the histological observations of inflammatory and necrotic lesions in mesenteric arteries. Some gene expression changes suggest that the development of the lesions could follow a primary modulation of the vascular tone in response to the pharmacological effect of the compound. Activation of genes coding for pro- and antioxidant enzymes, cytokines, adhesion molecules, and tissue inhibitor of metalloproteinase 1 (TIMP-1) indicates that biomechanical stimuli may contribute to vascular oxidant stress, inflammation, and tissue remodeling. TIMP-1 appeared to be an early and sensitive predictive biomarker of the inflammatory and the tissue remodeling components of PDE4 inhibitor-induced vascular injury.

Antenatal Phosphodiesterase 4 Inhibition Restores Postnatal Growth and Pulmonary Development in a Model of Chorioamnionitis in Rabbits

“…Second, rolipram on its own increases lipolysis as described in an in vitro model of rat pups (Nakamura et al, 2004;Snyder et al, 2005). In addition, toxicological reports during preclinical studies demonstrated significant inflammation of the intestinal tract, suggesting pathological absorption of food (Larson et al, 1996;Daguès et al, 2007). This mechanism would better explain the differences noted between group Cϩ and controls and group Cϩ versus groups CϩRϩ and Rϩ at birth, because animals treated with rolipram made up for the weight restriction as soon as rolipram infusion was stopped, and group CϩRϩ recovered normal weight at day 5 compared with controls.…”

A bilayer small diameter in vitro vascular model for evaluation of drug induced vascular injury

“…Drug-induced vascular injury has been elusive in that although inflammatory biomarkers have some correlation with DIVI, no vascular-specific biomarkers have been identified that reproducibly correlate with the formation of DIVI despite an exhaustive investigation of molecular 3,7,8,13,16 and imaging markers. 15 This model is the first to incorporate the co-culture of ECs and SMCs with flow and a porous internal elastic lamina to evaluate drugs for DIVI.…”

“…A pilot test of a candidate drug (CI-1044) known to cause DIVI [12][13][14][15] was performed. In the two control devices, whole blood flowed through the devices at arterial shear without any visual extravasation of RBCs, as shown in Fig.…”

“…RBC extravasation after CI-1044 treatment may have been due to deleterious effects of the compound on the endothelial junction, or other EC stress response, such as vascular oxidant stress and inflammation as reported in the previous in vivo studies of CI-1044. 13 Future studies will include immunohistochemical analysis and permeability assays to further evaluate mechanisms underlying RBC extravasation in DIVI.…”

Nonclinical Safety Biomarkers of Drug-induced Vascular Injury

“…Functionally, most genes differentially regulated in both ECs and VSMCs correspond to proteins involved in protein transport, cellular metabolism/energy, and cell movement; only 3% of the genes of ECs were associated with immune function and inflammation. Thus, the candidate genes were considered to represent signals derived from the vasculature itself and not from the secondary inflammatory and acute phase responses as in earlier studies (Dagues et al 2007). …”