Staining For CD73 Research Articles

CD73 expression in tissue granulomas in distinguishing intestinal tuberculosis from Crohn’s disease in a South African cohort

Introduction: Overlap of clinical, endoscopic and radiographic features, coupled with a poor microbiological yield makes differentiating Crohn’s disease (CD) from intestinal tuberculosis (ITB) challenging. A potential histological differentiating mechanism is the use of immunohistochemical staining for the mesenchymal stem cell marker CD73, as a pilot study showed ITB but not CD granulomas stained positive for this marker. The aim of this study was to assess the value of CD73 in differentiating ITB from CD granulomas in a South African cohort.Methods: Patients with confirmed CD or ITB were identified from a pathology database. Tissue sections were reviewed by a pathologist to confirm the presence of granulomas. These were then stained with a mouse monoclonal anti-CD73 antibody. The slides were examined together by a pathologist and gastroenterologist in a blinded manner for anti-CD73 staining around granulomas.Results: Ninety six cases were available for analysis; 50 cases of ITB and 46 cases of CD. Thirty percent of CD granulomas (14/46) stained positive for CD73, whereas CD73 positivity was seen in 52% (26/50) of cases of ITB. This was statistically significant (OR 2.48, 95% CI 1.1–5.72, p = .03). The area under the curve (AUC) was 0.61. Sensitivity of CD73 in predicting ITB was 52% and specificity was 70%. Overall CD73 staining of granulomas correctly classified only 60% of cases.Conclusions: In our study we have shown that significantly more patients with ITB express CD73 in their granulomas than those with CD. However the relatively poor sensitivity, specificity and AUC make this test unlikely to be of value in our clinical practice.

The 8‐fold quadrant dissection method for ex vivo human interventional retinal experimentation

PurposeRetinal research relies on animal and in‐vitro models which lack many of the characteristics of human retina. We have instead established a reproducible ex‐vivo model of primary retinal explants derived from human donor eye cups.MethodsA dissection strategy performed independently by two investigators was designed to maximize retinal tissue whilst maintaining experimentally reproducible fragments of retina suitable for experimental purposes. The retina was divided into 4 quadrants through the fovea and equivalent distribution of photoreceptors between quadrants was confirmed with CD73 staining in 7 pairs of donor eyes with flow cytometry. In the 8 quadrants from each of the 7 donors, the standard error in proportion of photoreceptors was 0.8–2.3%.ResultsCellular composition of free floating retinal explants were followed for 2 months in 10 retinas with quadrant dissection and 8 with random dissection. Explants could be maintained for 2 months with live populations of photoreceptors, ganglion cells and Müller cells detected by flow cytometry. In contrast, amacrine and horizontal cells, decreased by 90% at 7 days. Only quadrant dissection from the same patient showed reproducible and reliable proportions of cell populations between dissections at any time point. There was no statistically significant relationship between the proportion of any cell population and donor age, time after death, time to storage or time in storage.ConclusionsThe 8 fold quadrant dissection method from a single donor forms an attractive human experimental model for interventional testing in retinal research. We demonstrate the utility of this model in a simple neuroprotection study, showing that insulin protected against CoCl2 induced hypoxia in human photoreceptors.