Effect of d,l-ethionine administration on the histomorphology of canine pancreatic acinar and beta-cells

Evaluation of the Relative Performance of Pancreas-Specific MicroRNAs in Rat Plasma as Biomarkers of Pancreas Injury

Drug-induced pancreatic injury (DIPI) has become linked in recent years to many commonly prescribed medications from several pharmacological classes. Diagnosis is currently most often focused on identification of acute pancreatitis and generally based on subjective clinical assessment and serum amylase and lipase enzymatic activity, which have been criticized as being insufficiently sensitive and specific. The lack of novel noninvasive biomarkers of DIPI can impede the advancement of drug candidates through nonclinical development and translation into clinical settings. Pancreas-specific microRNAs (miRNAs) are currently being evaluated as biomarkers of DIPI that may outperform and/or add value to the interpretation of amylase and lipase. To assess the relative performance of these novel miRNAs, a comprehensive evaluation was conducted to determine the sensitivity and specificity of detecting DIPI in rats. Four miRNAs were evaluated (miR-216a-5p, miR-216b-5p, miR-217-5p, and miR-375-3p) in plasma from 10 studies in which rats were treated with known pancreatic toxicants to assess sensitivity, and from 10 different studies in which toxicity was evident in tissues other than pancreas to assess specificity. The candidate miRNA biomarker performance was compared with amylase and lipase, and receiver operator characteristics (ROC) were determined. Analysis of ROCs demonstrated that all four miRNAs outperformed amylase and lipase in monitoring acute pancreatic injury defined as acinar cell degeneration/necrosis. Specifically, miR-217-5p had the highest performance among all biomarkers assessed. The increased sensitivity and specificity of these miRNAs support their use as biomarkers of DIPI, thereby adding value to the interpretation of amylase and lipase measurements in nonclinical studies. The potential for miRNAs to serve as translational biomarkers in the clinic for the monitoring of DIPI is also supported by this investigation.

Histopathological examination of the pancreas of the Koala (Phascolarctos cinereus)

This retrospective study, which was based on koala pancreatic specimens taken 2, 24, 48 and 72h after death, showed that the degree of autolysis did not necessarily exclude histopathological examination. Disorders not previously reported in the pancreas of koalas included the following: inflammation and necrosis; atrophy and fibrosis of exocrine pancreatic tissue; lymphosarcoma; pancreatic heterotopy; and ductal adenocarcinoma.

Cellular proliferation in the canine pancreas after d,l-ethionine dosage as detected by double immunohistochemical labelling

d,l-Ethionine produces pancreatic exocrine necrosis and islet proliferation in hamsters and dogs. As a first step in examining whether induction of islet proliferation has therapeutic applications in animals with exhausted or destroyed insulin-producing beta-cells, we studied pancreatic cellular proliferation after intravenous administration of d,l-ethionine in normal dogs. Double immunohistochemical labelling of pancreatic tissue was used to identify proliferating cells in three groups of six clinically normal crossbred dogs administered d,l-ethionine (100 mg/kg) intravenously three times a week for two weeks. Six additional dogs served as untreated controls. Group I was euthanased and necropsied on day 15 (72 hours after the final dose of ethionine). Groups II and III were euthanased on days 29 and 43 respectively. Utilising markers for proliferating nuclei, insulin and cytokeratin, proliferating cells were classified as acinar, endocrine (both intra or extra-islet), duct or 'other' (i.e. infiltrative or interstitial) and counted under the light microscope (40x magnification). Compared to controls, an increase in the number of proliferating cells was found in all categories except ducts. Acinar cells demonstrated statistically significant (p < 0.05) proliferation, greatest two weeks after ethionine cessation continuing over four weeks. The interstitial, infiltrative or 'other' group also showed proliferation, however this was a more immediate response, which substantially decreased two weeks after ethionine administration. Endocrine cells showed only minor and non-significant proliferative activity and were probably not responsible for a significant increase in apparent beta-cell mass. The number of proliferating duct cells was inconsequential and there appeared to be no specific relationship between any cell populations and duct cells.