BackgroundThe objective evaluation of endoscopic disease activity is key in ulcerative colitis (UC). A composite of endoscopic and histological factors is the goal in UC treatment. We aimed to develop an operator-independent computer-based tool to determine UC activity based on endoscopic images.MethodsFirst, we built a computer algorithm using data from 29 consecutive patients with UC and 6 healthy controls (construction cohort). The algorithm (red density: RD) was based on the red channel of the red-green-blue pixel values and pattern recognition from endoscopic images. The algorithm was refined in sequential steps to optimise correlation with endoscopic and histological disease activity. In a second phase, the operating properties were tested in patients with UC flares requiring treatment escalation. To validate the algorithm, we tested the correlation between RD score and clinical, endoscopic and histological features in a validation cohort.ResultsWe constructed the algorithm based on the integration of pixel colour data from the redness colour map along with vascular pattern detection. These data were linked with Robarts histological index (RHI) in a multiple regression analysis. In the construction cohort, RD correlated with RHI (r=0.74, p<0.0001), Mayo endoscopic subscores (r=0.76, p<0.0001) and UC Endoscopic Index of Severity scores (r=0.74, p<0.0001). The RD sensitivity to change had a standardised effect size of 1.16. In the validation set, RD correlated with RHI (r=0.65, p=0.00002).ConclusionsRD provides an objective computer-based score that accurately assesses disease activity in UC. In a validation study, RD correlated with endoscopic and histological disease activity.

Both angiotensin-converting enzyme (ACE) inhibitors and angiotensin II type 1 (AT 1 ) receptor blockers have been demonstrated to improve symptoms and prognosis in heart failure (HF). We compared the effects of ACE inhibition and AT 1 receptor blockade on myocardial ␤-adrenoceptor desensitization in rabbits with HF established 3 weeks after myocardial infarction (MI) with left circumflex coronary artery ligation. Rabbits with MI were randomized to no treatment, the ACE inhibitor temocapril (0.5 mg/kg/day) or AT 1 receptor blocker valsartan (3 mg/kg/day). Echocardiographic examinations showed that, relative to rabbits with untreated MI, rabbits receiving temocapril or valsartan had a limitation of cardiac remodeling and prevention of the development of systolic dysfunction. Circulating plasma norepinephrine levels that were markedly elevated in MI animals were strongly inhibited by temocapril or valsartan therapy. ␤-Adrenoceptor density, ␤-adrenoceptor proportion showing high-affinity agonist binding, and basal and isoproterenol-stimulated adenylate cyclase activities were significantly reduced in MI rabbits. These defects were similarly reversed by temocapril or valsartan. Importantly, as found in human HF, myocardial protein levels of ␤-adrenoceptor kinase 1 and G i␣ were significantly elevated in MI rabbits, suggesting that these molecules are contributing to the defects in myocardial ␤-adrenoceptor signaling. The expression levels of these molecules were normalized equally by both treatments. The results suggest that pharmacologically different interventions in the reninangiotensin system can equivalently improve the derangements in the ␤-adrenoceptor signaling system in the failing heart. This may be important for the beneficial effects of these agents in HF.

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