Coproporphyrins in plasma and urine can be appropriate clinical biomarkers to recapitulate drug-drug interactions mediated by organic anion transporting polypeptide inhibition.

ABSTRACT In the present study, an open-label, three-treatment, threeperiod clinical study of rosuvastatin (RSV) and rifampicin (RIF) when administered alone and in combination was conducted in 12 male healthy subjects to determine if coproporphyrin I (CP-I) and coproporphyrin III (CP-III) could serve as clinical biomarkers for organic anion transporting polypeptide 1B1 (OATP1B1) and 1B3 that belong to the solute carrier organic anion gene subfamily. Genotyping of the human OATP1B1 gene was performed in all 12 subjects and confirmed absence of OATP1B1*5 and OATP1B1*15 mutations. Average plasma concentrations of CP-I and CP-III prior to drug administration were 0.91 6 0.21 and 0.15 6 0.04 nM, respectively, with minimum fluctuation over the three periods. CP-I was passively eliminated, whereas CP-III was actively secreted from urine. Administration of RSV caused no significant changes in the plasma and urinary profiles of CP-I and CP-III. RIF markedly increased the maximum plasma concentration (C max ) of CP-I and CP-III by 5.7-and 5.4-fold (RIF) or 5.7-and 6.5-fold (RIF1RSV), respectively, as compared with the predose values. The area under the plasma concentration curves from time 0 to 24 h (AUC 0-24h ) of CP-I and CP-III with RIF and RSV increased by 4.0-and 3.3-fold, respectively, when compared with RSV alone. In agreement with this finding, C max and AUC 0-24h of RSV increased by 13.2-and 5.0-fold, respectively, when RIF was coadministered. Collectively, we conclude that CP-I and CP-III in plasma and urine can be appropriate endogenous biomarkers specifically and reliably reflecting OATP inhibition, and thus the measurement of these molecules can serve as a useful tool to assess OATP drug-drug interaction liabilities in early clinical studies

11β-Hydroxysteroid Dehydrogenase Type 1 Gene Knockout Attenuates Atherosclerosis and In Vivo Foam Cell Formation in Hyperlipidemic apoE^−/− Mice

<div><h3>Background</h3><p>Chronic glucocorticoid excess has been linked to increased atherosclerosis and general cardiovascular risk in humans. The enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) increases active glucocorticoid levels within tissues by catalyzing the conversion of cortisone to cortisol. Pharmacological inhibition of 11βHSD1 has been shown to reduce atherosclerosis in murine models. However, the cellular and molecular details for this effect have not been elucidated.</p> <h3>Methodology/Principal Findings</h3><p>To examine the role of 11βHSD1 in atherogenesis, 11βHSD1 knockout mice were created on the pro-atherogenic apoE^−/− background. Following 14 weeks of Western diet, aortic cholesterol levels were reduced 50% in 11βHSD1^−/−/apoE^−/− mice vs. 11βHSD1^+/+/apoE^−/− mice without changes in plasma cholesterol. Aortic 7-ketocholesterol content was reduced 40% in 11βHSD1^−/−/apoE^−/− mice vs. control. In the aortic root, plaque size, necrotic core area and macrophage content were reduced ∼30% in 11βHSD1^−/−/apoE^−/− mice. Bone marrow transplantation from 11βHSD1^−/−/apoE^−/− mice into apoE^−/− recipients reduced plaque area 39–46% in the thoracic aorta. In vivo foam cell formation was evaluated in thioglycollate-elicited peritoneal macrophages from 11βHSD1^+/+/apoE^−/− and 11βHSD1^−/−/apoE^−/− mice fed a Western diet for ∼5 weeks. Foam cell cholesterol levels were reduced 48% in 11βHSD1^−/−/apoE^−/− mice vs. control. Microarray profiling of peritoneal macrophages revealed differential expression of genes involved in inflammation, stress response and energy metabolism. Several toll-like receptors (TLRs) were downregulated in 11βHSD1^−/−/apoE^−/− mice including TLR 1, 3 and 4. Cytokine release from 11βHSD1^−/−/apoE^−/−-derived peritoneal foam cells was attenuated following challenge with oxidized LDL.</p> <h3>Conclusions</h3><p>These findings suggest that 11βHSD1 inhibition may have the potential to limit plaque development at the vessel wall and regulate foam cell formation independent of changes in plasma lipids. The diminished cytokine response to oxidized LDL stimulation is consistent with the reduction in TLR expression and suggests involvement of 11βHSD1 in modulating binding of pro-atherogenic TLR ligands.</p> </div

Ingenuity canonical pathways significantly impacted in peritoneal macrophages from Western-diet fed 11β^+/+/apoE^−/− and 11β^−/−/apoE^−/− mice.

<p>Ingenuity canonical pathways significantly impacted in peritoneal macrophages from Western-diet fed 11β^+/+/apoE^−/− and 11β^−/−/apoE^−/− mice.</p

Atherosclerosis development with 11βHSD1-deficient bone marrow reconstitution.

<p><b>A</b>) 11βHSD1 gene expression levels in whole blood taken at study termination from apoE knockout mice reconstituted with 11βHSD1^−/−/apoE^−/− (n = 12) or 11βHSD1^+/+/apoE^−/− (n = 13) bone marrow cells. <b>B</b>) Plasma total cholesterol levels 12 weeks post Western diet feeding. <b>C</b>) Quantification of en face lesion area with oil red O staining in the whole thoracic aorta, <b>D</b>) descending aorta and <b>E</b>) aortic arch. <b>F</b>) Aortic root lesion area. Data are from a single independently run in vivo study. Significance vs. control: *p≤0.05.</p

In vivo foam cell analysis.

<p><b>A</b>) Peritoneal macrophage total cholesterol mass normalized to cell count from hyperlipidemic 11βHSD1^+/+/apoE^−/− (n = 13) and 11βHSD1^−/−/apoE^−/− (n = 16) mixed-sex mice. <b>B</b>) Peritoneal macrophages (MΦ) harvested by lavage from 11βHSD1^+/+/apoE^−/− (left upper and lower images) and 11βHSD1^−/−/apoE^−/− (right upper and lower images) mice stained with oil red O and hematoxylin. Magnification of top images 40X and lower images 100X. Data are pooled from two independently run studies. Significance vs. control: *p≤0.05.</p

11βHSD1 mRNA expression profiles from 11βHSD1^+/+/apoE^−/− and 11βHSD1^−/−/apoE^−/− mice.

<p>Gene expression levels in <b>A</b>) liver, <b>B</b>) adipose, <b>C</b>) spleen and <b>D</b>) thioglycollate-elicited peritoneal macrophages. Values normalized to 11βHSD1<b>^+/+</b> levels. Data are from a subset analysis of mixed-sex mice.</p