Background Fibrosis is associated with various cardiac pathologies and dysfunction. Current quantification methods are time-consuming and laborious. We describe a semiautomated quantification technique for myocardial fibrosis and validated this using traditional methods. Methods Pulmonary Hypertension (PH) was induced in adult Wistar rats by subcutaneous monocrotaline (MCT) injection(40 mg/kg). Cryosections of myocardial tissue (5 μm) of PH rats (n=9) and controls (n=9) were stained using Picrosirius red and scanned with a digital microscopic MIRAX slide scanner. From these sections 21 images were taken randomly of each heart. Using ImageJ software a macro for automated image analysis of the amount of fibrosis was developed. For comparison, fibrosis was quantified using traditional polarisation microscopy. Both methods were correlated and validated against stereology as the gold standard. Furthermore, the method was tested in paraffin-embedded human tissues. Results Automated analysis showed a significant increase of fibrosis in PH hearts vs. control. Automated analysis correlated with traditional polarisation and stereology analysis (r 2 =0.92 and r 2 =0.95 respectively). In human heart, lungs, kidney, and liver, a similar correlation with stereology (r 2 =0.91) was observed. Time required for automated analysis was 22% and 33% of the time needed for stereology and polarisation analysis respectively. Conclusion Automated quantification of fibrosis is feasible, objective, and time-efficient.

Abstract.Background: Fibrosis is associated with various cardiac pathologies and dysfunction. Current quantification methods are time-consuming and laborious. We describe a semi-automated quantification technique for myocardial fibrosis and validated this using traditional methods.Methods: Pulmonary Hypertension (PH) was induced in adult Wistar rats by subcutaneous monocrotaline (MCT) injection (40 mg/kg). Cryosections of myocardial tissue (5 µm) of PH rats (n = 9) and controls (n = 9) were stained using Picrosirius red and scanned with a digital microscopic Mirax slide scanner. From these sections 21 images were taken randomly of each heart. Using ImageJ software a macro for automated image analysis of the amount of fibrosis was developed. For comparison, fibrosis was quantified using traditional polarisation microscopy. Both methods were correlated and validated against stereology as the gold standard. Furthermore, the method was tested in paraffin-embedded human tissues.Results: Automated analysis showed a significant increase of fibrosis in PH hearts vs. control. Automated analysis correlated with traditional polarisation and stereology analysis (r 2 = 0.92 and r 2 = 0.95, respectively). In human heart, lungs, kidney and liver, a similar correlation with stereology (r 2 = 0.91) was observed. Time required for automated analysis was 22 and 33% of the time needed for stereology and polarisation analysis, respectively.Conclusion: Automated quantification of fibrosis is feasible, objective and time-efficient.

Objective. Systemic sclerosis-associated pulmonary arterial hypertension (SScPAH) has a disturbed function of the right ventricle (RV) when compared to idiopathic PAH (IPAH). Systemic sclerosis may also affect the heart. We hypothesize that RV differences may occur at the level of interstitial inflammation and—fibrosis and compared inflammatory cell infiltrate and fibrosis between the RV of SScPAH, IPAH, and healthy controls. Methods. Paraffin-embedded tissue samples of RV and left ventricle (LV) from SScPAH (n = 5) and IPAH (n = 9) patients and controls (n = 4) were picrosirius red stained for detection of interstitial fibrosis, which was quantified semiautomatically. Neutrophilic granulocytes (MPO), macrophages (CD68), and lymphocytes (CD45) were immunohistochemically stained and only interstitial leukocytes were counted. Presence of epi- or endocardial inflammation, and of perivascular or intimal fibrosis of coronary arteries was assessed semiquantitatively (0–3: absent to extensive). Results. RV's of SScPAH showed significantly more inflammatory cells than of IPAH (cells/mm2, mean ± sd MPO 11 ± 3 versus 6 ± 1; CD68 11 ± 3 versus 6 ± 1; CD45 11 ± 1 versus 5 ± 1 , P < .05) and than of controls. RV interstitial fibrosis was similar in SScPAH and IPAH (4 ± 1 versus 5 ± 1%, P = .9), and did not differ from controls (5 ± 1%, P = .8). In 4 SScPAH and 5 IPAH RV's foci of replacement fibrosis were found. No differences were found on epi- or endocardial inflammation or on perivascular or intimal fibrosis of coronary arteries. Conclusion. SScPAH RVs display denser inflammatory infiltrates than IPAH, while they do not differ with respect to interstitial fibrosis. Whether increased inflammatory status is a contributor to altered RV function in SScPAH warrants further research.

We determined the effects of single and combination treatment with Bosentan [an ET type A (ET A)/type B (ETB) receptor blocker] and Sildenafil (a PDE5 inhibitor) on RV function and oxidative metabolism in monocrotaline (MCT)-induced PAH. Fourteen days after MCT injection, male Wistar rats were orally treated for 10 days with Bosentan, Sildenafil, or both. RV catheterization and echocardiography showed that MCT clearly induced PAH. This was evidenced by increased RV systolic pressure, reduced cardiac output, increased pulmonary vascular resistance (PVR), and reduced RV fractional shortening. Quantitative histochemistry showed marked RV hypertrophy and fibrosis. Monotreatment with Bosentan or Sildenafil had no effect on RV systolic pressure or cardiac function, but RV fibrosis was reduced and RV capillarization increased. Combination treatment did not reduce RV systolic pressure, but significantly lowered PVR, and normalized cardiac output, RV fractional shortening, and fibrosis. Only combination treatment increased the mitochondrial capacity of the RV, as reflected by increased succinate dehydrogenase and cytochrome c oxidase activities, associated with an activation of PKG, as indicated by increased VASP phosphorylation. Moreover, significant interactions were found between Bosentan and Sildenafil on PVR, cardiac output, RV contractility, PKG activity, and mitochondrial capacity. These data indicate that the combination of Bosentan and Sildenafil may beneficially contribute to RV adaptation in PAH, not only by reducing PVR but also by acting on the mitochondria in the heart. Bosentan; Sildenafil; mitochondria; oxidative capacity; chronic heart failure PULMONARY ARTERIAL HYPERTENSION (PAH) is a severe progressive disease of the small lung vasculature leading to increased pulmonary vascular resistance (PVR). The right ventricle (RV) hypertrophies to withstand the rise in PVR and maintain cardiac output (CO) (16,48). Subsequently, RV contractile dysfunction occurs, and failure may develop (8, 51). Many factors influence the capacity of the RV to adapt to PAH, such as the degree of RV wall stress, myocardial ischemia, or microvascular endothelial dysfunction. However, the exact sequence of events leading the RV toward failure, and the effects of treatments to counteract this process remain uncertain (51).Various treatments for PAH have been developed over time, which primarily act as vasodilators of the pulmonary vasculature. These treatments include anticoagulant therapy, prostacyclin infusion, endothelin (ET) receptor blockade, and phosphodiesterase-5 (PDE5) inhibition (9, 25). ET receptor blockade by Bosentan and PDE5 inhibition by Sildenafil are both common strategies in PAH treatment (9,25,43). The ET system is highly active in PAH and causes sustained vasoconstriction of pulmonary arteries. It increases the mitogenic activity of smooth muscle cells and fibroblasts in the pulmonary vessel wall, thereby decreasing the lumen of pulmonary vessels, also contributing to increased pulmonary vascular resistance (PVR) ...

The effect of specific chemotherapy (praziquantel) on liver function tests and on the distribution of collagen types I, III, IV and V was studied by indirect immunofluorescence in Swiss albino mice infected with Schistosoma mansoni. Treatment was started at 7 and 12 weeks after infection. Groups of treated and non-treated mice were killed 14 and 20 weeks after infection. Reduction in the amount of collagen and improvement of liver function were observed, especially when treatment was initiated early (7 weeks after infection), while collagen type III almost disappeared during the period of observation (13 weeks after treatment). The results indicate the importance of early specific treatment for schistosomiasis.