Diethylcarbamazine treatment reduced the increment in lung tissue eicosanoids.

<p>Shown are the data obtained from normal control rats, animals treated with SU5416 and exposed to hypoxia for 4 weeks (SuHx) (n = 4) and animals concomitantly treated with diethylcarbamazine (DEC) (n = 6). DEC treatment blunted the increase of LTC4, LTD4, 8, 12, and 15 HETE. In addition, DEC treatment also blunted the increase in 6-keto PGF1α (The stable prostacyclin metabolite) but not the increase in tissue 8-iso PGF2α. * P<0.05 vs. control, #P<0.05 vs. SuHx.</p

Eicosanoid enzyme protein Western blot data.

<p>In lung tissue homogenates there is an increased expression of cPLA2 and COX-2 in the SuHx animals when compared to normal control lung tissues. The overexpression of the COX-2 and cPLA2 proteins is significantly reduced in the lungs from the SuHx animals treated chronically with the COX-2 inhibitor SC-58125 (A). The protein expression is referenced to lung tissue β-actin (B and C). * P<0.05 vs. control, #P<0.05 vs. SuHx. (n = 4).</p

Effects of SC-58125 on hemodynamics, pulmonary artery muscularization and angioobliteration.

<p>The right ventricular systolic pressure measured (using a Millar catheter) is reduced in the SuHx rats following 3 weeks of treatment of the animals with the COX-2 inhibitor (A) (n = 4). There is no significant reduction of the right ventricular hypertrophy (RV/LV+S) (B) (n = 4). (C) Scale bar = 100μm. There is no significant reduction of the angioobliteration neither the muscularization in the lungs from rats treated with the inhibitor (D, E) (n = 4). MWT = media wall thickness, ED = external diameter. *P<0.05 vs. control, #P<0.05 vs. SuHx. vWF = Von Willebrand Factor.</p

Diethylcarbamazine treatment of animals with established lung vascular disease (intervention trial).

<p>(A) Right ventricular systolic pressure (RVSP) in animals subjected to the SuHx protocol (SuHx) (n = 6) and animals treated with diethylcarbamazine (DEC) after pulmonary hypertension had been established (n = 5). There is a treatment related reduction in the RVSP. (B) There is a reduction in the DEC-treated animals’ RV hypertrophy and (C) (n = 6). There is no significant reduction in the right ventricular internal diastolic diameter (RVID/d) (n = 6). (D) Shows representative sections from SuHx rat’s lung treated with a daily dose of 50 mg/kg DEC for 2 weeks, scale bar = 100 μm. (E) Shows that the percentage of open vessels are greater and that there are fewer obliterated vessels after DEC treatment (n = 6). (F) Shows a reduction in the average of perivascular inflammation after treatment with DEC (n = 6). * P<0.05 vs. control, #P<0.05 vs. SuHx.</p

Eicosanoid metabolite concentrations (expressed in ng/mg lung tissue weight) in the lungs.

<p>There is an increase in 6-ketoPGF1α (The stable metabolite of prostacyclin), and of PGE2 in the SuHx lung tissues. There was a trend for an increase of the LTC4 and LTD4 levels. Chronic treatment of SuHx rats with the COX-2 inhibitor SC-58125 did not prevent the increase in lung tissue concentration of 6-ketoPGF1α or PGE2 (A, C). The COX-2inhibitor trended to affect the lung tissue increase of the LTC4 and LTD4 (E, F). * P<0.05 vs. control, #P<0.05 vs. SuHx. (n = 4).</p

Diethylcarbamazine ameliorated pulmonary angioproliferation & the development of severe PAH.

<p>Measurement of the right ventricular systolic pressure (using a Millar catheter) shows a reduction in the RVSP in the SuHx rats following 3 weeks of treatment of the animals with diethylcarbamazine (DEC, 50 mg/kg) (A) (n = 6–8). While there is a reduction of the RVSP in the DEC treated animals there is a trend to reduction in the right ventricular hypertrophy but it did not reach a statistical significance(RV/LV+S) (B) (n = 6–8). (C) Scale bar = 100μm. There is a significant reduction of angioobliteration and muscularization in the lungs from rats treated with DEC (D, E) (n = 6–8). Panel (F) shows that DEC treatment reduced the degree of perivascular cell accumulation (n = 6–8). MWT = media wall thickness, ED = external diameter. * P<0.05 vs. control, #P<0.05 vs. SuHx. vWF = von Willebrand factor</p

Immunofluorescence for representative tissue samples shows the labeling of lumen-obliterating cells; 5-LO protein expression is increased in the SuHx lungs.

<p>Antibodies directed against 5-LO and LTA4 hydrolase were used (B, D), controls (A, C). In control lung tissues there was only sparse labeling of arteriolar endothelial cells for 5-LO, while the LTA4 hydrolase antibody stained alveolar septal cells in addition. In the lungs from the SuHx rats many of the lumen obliterating cells and also perivascular cells were intensely labeled by both antibodies. DAPI = nuclear staining, DIC = differential interference contrast, 5-LO = 5-Lipoxygenase, LTA4-H = Leukotriene A4 hydrolase, magnification 40X. The lung tissue 5-LO protein concentration was increased in the SuHx lungs when analyzed by western blot. (n = 4–6).</p

Eicosanoid concentrations in right ventricular tissue samples (expressed as ng/mg right ventricle tissue weight).

<p>6-keto-PGF1α, PGE2, PGD2 and TXB2 levels were elevated in the right ventricle tissues from SuHx rats (A, B, C and D) and this increase was prevented in animals treated with the COX-2 inhibitor. Eicosapentanoic acid (Eicpent) and docosahexanoic acid (DHA) levels were reduced in the RV tissues from the SuHx animals (E, F); treatment with SC-58125 did not affect the levels of eicosapentanoic or docosahexanoic acid levels. * P<0.05 vs. control, #P<0.05 vs. SuHx. (n = 4).</p

Losartan, but not hydralazine, reduces ceramide-mediated endothelium-dependent contractions in isolated carotid arteries of SHR.

<p>(<b>A</b>) Typical tracing of 0.1 U/mL sphingomyelinase (SMase)-induced endothelium-dependent contraction in carotid arteries of untreated, losartan-treated and hydralazine-treated SHR. (<b>B</b>) Quantification of peak “EDCF-mediated contractile responses” to SMase. Data are expressed as mean±SEM, n = 7–8, * p<0.05 compared to untreated SHR.</p

Losartan but not hydralazine reduces endothelial iPLA₂ expression.

<p>(<b>A</b>) Immunohistochemical staining (left) and quantification (right) of SHR carotid artery segments depicting cell nuclei staining (blue), with the von Willebrand Factor (vWF) endothelium marker (green) and calcium-independent phospholipase A₂ (iPLA₂; red), (<b>B</b>) cyclooxygenase-1 (COX-1; red), (<b>C</b>) thromboxane synthase (TXAS; red). Scale bars represent 100 µm. Data are expressed as mean±SEM, n = 7–8, * p<0.05 compared to untreated SHR.</p