Cellular and humoral immune responses in atrophic lymphocytic pancreatitis in German shepherd dogs and rough-coated collies

The most common cause for the clinical signs of exocrine pancreatic insufficiency (EPI) in dogs is pancreatic acinar atrophy (PAA). In the subclinical phase of EPI, before total atrophy occurs, exocrine pancreas is affected by infiltrative lymphocytic inflammation, which gradually leads to selective destruction and atrophy of the acinar tissue.Here, we analyzed the role of cell-mediated and humoral immune mechanisms in the pathogenesis of atrophic lymphocytic pancreatitis in German shepherd dogs and rough-coated collies. Pancreas biopsies and serum samples were obtained from 12 dogs with subclinical EPI (SEPI), 13 dogs with clinical EPI and 13 healthy control dogs. Immunohistochemical analysis showed that, in the subclinical phase, the majority of the infiltrating lymphocytes were T-cells with an almost equal number of CD4+ 'T-helper' and CD8+ 'cytotoxic' T-lymphocytes. The distribution of the two lymphocyte subsets was different. Typically, the CD4+ cells were present in large cellular infiltrates in the affected parenchyma, and the scattered CD8+ cells had infiltrated both the affected and the normal parenchyma. In sections where destruction of acinar parenchyma was present, the CD8+ T-cells were predominant. In cases of marked T-cell infiltration, CD79+ B-lymphocytes and plasma cells, and lysozyme-positive macrophages were also detected. Lymphoid follicle germinal centers with a majority of cells staining positively for CD79 were found. The lymphocytic infiltration in the totally atrophic tissue of dogs with clinical EPI was less prominent. Indirect immunofluorescence staining showed serum antibodies reacting weakly with pancreatic acinar cells in five out of nine dogs with subclinical and three out of 10 dogs with clinical EPI, but not in the control dogs. The results suggest that the tissue destruction is largely T-cell-mediated, although the presence of numerous B-lymphocytes and pancreas-specific antibodies in the sera of some dogs indicate that humoral mechanisms are also involved. In conclusion, this study suggests that the atrophic lymphocytic pancreatitis in German shepherds and rough-coated collies is an autoimmune disease.

Evaluation of serum feline trypsin-like immunoreactivity for the diagnosis of pancreatitis in cats

OBJECTIVE

To evaluate serum feline trypsin-like immunoreactivity (fTLI) concentration and results of abdominal ultrasonography, CBC, and serum biochemical analyses for diagnosis of pancreatitis in cats.

DESIGN

Prospective study.

ANIMALS

28 cats with clinical signs compatible with pancreatitis.

PROCEDURE

Serum fTLI concentrations were determined, and abdominal ultrasonography, CBC, and serum biochemical analyses were performed prior to histologic evaluation of pancreatic, hepatic, and intestinal specimens. On the basis of histologic results, cats were categorized as having a normal pancreas (n = 10), pancreatic fibrosis with ongoing inflammation (9), pancreatic fibrosis without inflammation (4), and acute necrotizing pancreatitis (5). Serum fTLI concentrations and results of CBC, serum biochemical analyses, and histologic evaluation of hepatic and intestinal specimens were compared among groups.

RESULTS

Significant differences in serum fTLI concentrations or any hematologic or biochemical variable were not detected among the 4 groups of cats. Median serum fTLI concentrations were 51 micrograms/L (range, 18 to 200 micrograms/L) in cats with a normal pancreas, 32 micrograms/L (range, 12 to > 200 micrograms/L) in cats with pancreatic fibrosis and ongoing inflammation, 124 micrograms/L (range, 36 to > 200 micrograms/L) in cats with pancreatic fibrosis without ongoing inflammation, and 30 micrograms/L (range, 24 to 84 micrograms/L) in cats with acute necrotizing pancreatitis. We detected a high prevalence of concurrent hepatic and intestinal tract disease in cats with pancreatitis.

CONCLUSIONS AND CLINICAL RELEVANCE

In cats with clinical signs of pancreatitis, serum fTLI concentration is poorly associated with histopathologic diagnosis.

Caerulein-induced pancreatitis in Wistar rats

We describe a refined model of intravenous caerulein-induced pancreatitis by using osmotic infusion pumps in the conscious unrestrained Wistar rat. The volume of caerulein required for the 6-h infusion is loaded into PE-55 catheter tubing attached to an Alzet (Alza Corporation, Palo Alto, CA) implantable osmotic pump that has been primed with saline. The technique has reliably induced mild edematous pancreatitis, which we verified histologically. Our refined model has the advantages of unrestrained animals, reduced animal handling and acclimation, and decreased cost.

Pancreatitis associated with potassium bromide/phenobarbital combination therapy in epileptic dogs

In a retrospective study, at least 10% of dogs receiving potassium bromide/phenobarbital combination therapy, compared with 0.3% of dogs receiving phenobarbital monotherapy, had probable pancreatitis. Pancreatitis may be a more frequent and more serious adverse effect of potassium bromide/phenobarbital combination therapy than has been reported previously.

Experimental models of acute pancreatitis: are they suitable for evaluating therapy?

Since randomized controlled studies of severe acute human pancreatitis can be performed only with restrictions, at least some aspects of innovative therapy concepts should first be clarified in animal experiments. In vitro trials are inadequate for this purpose since they cannot simulate the complex course of severe acute pancreatitis. Animal test results can be transferred to clinical practice if the results are based on trials with established models, standardized methods, and a study design imitating the clinical situation. This contribution discusses the demands on such an animal model of acute pancreatitis and a corresponding study protocol and presents models and protocols which meet these requirements. Concrete examples are presented to show that animal experiments are of great value under these conditions, especially in acute necrotizing pancreatitis. Further standardization of models, protocols, and monitoring should further improve future animal therapy studies at least to the extent that it is possible to select particularly promising substances, which should then be tested in randomized controlled trials.

Plasma and urinary trypsinogen activation peptide in healthy dogs, dogs with pancreatitis and dogs with other systemic diseases

OBJECTIVE

To determine the specificity and sensitivity of plasma and urinary trypsinogen activation peptide (TAP) concentrations in diagnosing pancreatitis in dogs.

DESIGN

Retrospective analysis of clinical cases.

PROCEDURE

Dogs were classified into three groups: healthy animals, dogs with confirmed pancreatitis and dogs with nonpancreatic disease, which clinically or biochemically resembled pancreatitis. This last group was further subdivided into dogs with renal and those with nonrenal disease. The plasma and urinary TAP concentration was determined by a competitive enzyme immunoassay. Clinical cases additionally had serum trypsin-like immunoreactivity concentration measured, as well as radiography and ultrasound of the abdomen and further diagnostic procedures. Nonparametric analysis of variance (Kruskal-Wallis test) was performed using Statistix 4.0 program.

RESULTS

There was a wide range of urinary TAP concentration in healthy dogs (mean 52.30 nmol/L, standard deviation 55.25) that made interpretation of urinary TAP concentrations difficult in the other groups. There was a narrow reference range for plasma TAP (mean 2.67 nmol/L, standard deviation 0.93). Plasma and urinary TAP concentrations, as well as urinary TAP to creatinine ratio, were all increased in dogs that died with necrotising pancreatitis. Values were not increased in mild, interstitial pancreatitis. Increased plasma TAP concentrations were also present in dogs with severe renal disease.

CONCLUSION

Plasma TAP concentration is a good prognostic indicator in naturally occurring pancreatitis in dogs. The failure of TAP to increase in mild pancreatitis, and the increase present in severe renal disease, suggests its measurement has limited application as a sole diagnostic tool for canine pancreatitis. Further investigations are required in order to explain the large variability of urinary TAP concentration and the presence of circulating TAP in healthy dogs.

Enterococcus hirae enteropathy with ascending cholangitis and pancreatitis in a kitten

A 2-month-old female Persian cat that had been showing episodes of anorexia and diarrhea for the previous 4 weeks was presented in shock and died 2 days later. Numerous Gram-positive cocci were located along the brush border of small intestinal villi, without significant inflammatory infiltration. Similar bacteria were present within hepatic bile ducts and pancreatic ducts and were associated with suppurative inflammation and exfoliation of epithelial cells. Culture of the liver and lung yielded bacteria identified as Enterococcus hirae. Fecal culture from an asymptomatic adult female from the same cattery also yielded large numbers of E. hirae. To our knowledge, this is the first report of E. hirae enteropathy in a cat and the first report of ascending cholangitis and ductal pancreatitis caused by an Enterococcus spp.

Histopathological and immunohistochemical studies on cetaceans found stranded on the coast of Italy between 1990 and 1997

Detailed histopathological and immunohistochemical studies were carried out on 24 cetaceans, 17 of which were striped dolphins (Stenella coeruleoalba), four bottlenose dolphins (Tursiops truncatus) and three Risso's dolphins (Grampus griseus), all found stranded on the Italian coast between 1990 and 1997. The most frequently detected lesions were chronic pneumonia (73.7% of the examined lungs), focal chronic pancreatitis (71.4%), non-purulent encephalitis (50%), chronic hepatitis (42.1%), and chronic focal interstitial nephritis (31.2%). The skin and the subcutaneous panniculus were often (33.3%) affected by parasitic diseases (Phyllobothrium delphini and Pennella sp.). An appreciable percentage of animals showed lymphoid depletion in their lymphatic organs (47.2%), as well as a high rate of parasitic infestations in their alimentary tracts (25%).

Tumor necrosis factor-alpha at presentation in 60 cases of spontaneous canine acute pancreatitis

Tumor necrosis factor-alpha (TNF) is a pleiotropic cytokine with profound and broad ranging effects on many cell types. There have been few publications investigating the role of TNF in spontaneous disease processes of dogs, particularly the role of this cytokine during endotoxaemia, shock and multiple organ dysfunction syndromes. Plasma samples taken at presentation from 60 dogs with spontaneous acute pancreatitis of varying severity levels (scored 0-4 in ascending severity) were assessed for TNF activity by bioassay and total TNF protein levels through a dot-blot immunoassay. TNF activity by bioassay was detected in 31% (4/13) of dogs presenting with severe disease (>50% expected mortality) as defined using a scoring system for organ compromise, and was not detectable in the remaining animals or healthy controls. TNF activity was detected in 66% (4/6) animals in the highest severity group (Score 4), these animals were showing severe multiple organ dysfunction. Total TNF protein levels, measured by dot-blot immunoassay, exhibited a wide range in all severity groups and healthy dogs. Dogs with detectable TNF activity were not distinguished from the other severity or healthy groups by immunoassay. The absence of detectable differences in total TNF protein levels between the various severity groups suggests that other factors may be crucial in determining the role of TNF in spontaneous canine acute pancreatitis and subsequent endotoxaemia and shock.

Exocrine pancreatic atrophy in German Shepherd Dogs and Rough-coated Collies: an end result of lymphocytic pancreatitis

Previously published studies of the pathology of canine exocrine pancreatic insufficiency (EPI) have been based on morphological findings during the clinical phase of the disease, when atrophy of acinar parenchyma occurs. Recently, low serum trypsinlike immunoreactivity (TLI) concentration has been shown to precede clinical signs, making it possible to diagnose EPI prior to onset of the clinical disease. This study presents histological and ultrastructural findings of pancreatic biopsies from 11 German Shepherd Dogs and 2 Rough-coated Collies with subclinical EPI (SEPI). These findings were compared with those from dogs with clinical EPI (n = 11) and healthy control dogs (n = 5). Biopsied tissue from dogs with SEPI typically contained both normal and atrophied acinar parenchyma. The most significant finding was the marked lymphocytic infiltration, which was most prevalent at the border zone of affected and nonaffected parenchyma but had spread into the normal acinar tissue. Numerous intraacinar lymphocytes were found. Most of the lymphocytes were positive by immunostaining for CD3. In more advanced stages of destruction, the findings were characteristic of pancreatic acinar atrophy. In the atrophied parenchyma, the inflammatory reaction, if present, was less prominent. Ultrastructural changes were in accordance with those of the histological study showing infiltration of lymphocytes both in affected acini and in acini that revealed no obvious ultrastructural changes. Progressive degenerative changes of acinar cells were considered a nonspecific finding. Apoptotic death of acinar cells was occasionally found. The inflammatory reaction was clearly shown to precede the pancreatic acinar atrophy, and the findings suggested that lymphocytic pancreatitis leads to atrophy of the pancreas. The possibility that EPI is an immune-mediated disease in German Shepherd Dogs and Rough-coated Collies is discussed.

Levels of total alpha-macroglobulin and trypsin-like immunoreactivity are poor indicators of clinical severity in spontaneous canine acute pancreatitis

Trypsin-like immunoreactivity and total alpha-macroglobulin levels were assessed in serum and plasma samples taken at presentation from 60 cases of spontaneous canine acute pancreatitis of varying clinical severity. Total alpha-macroglobulin was significantly decreased in all severity groups when compared to 119 healthy controls, however there were no significant differences between severity groups. Trypsin-like immunoreactivity was significantly elevated above assay reference range in all groups. Trypsin-like immunoreactivity was significantly elevated in dogs with severe disease when compared to those with mild disease. These results suggest that zymogen release and protease activation, while components of the pathology of spontaneous canine acute pancreatitis, are not directly associated with the onset of multiple organ failure seen in the most severe cases.

Evaluation of risk factors for fatal acute pancreatitis in dogs

OBJECTIVE

To identify risk factors associated with fatal acute pancreatitis in dogs.

DESIGN

Case-control study.

ANIMALS

70 case dogs with clinical evidence and histopathologic confirmation of fatal acute pancreatitis and 104 control dogs that had trauma, underwent necropsy, and did not have histologic evidence of acute pancreatitis.

PROCEDURE

Information on signalment, weight, body condition, medical history, concurrent disease, and results of histopathologic examination was obtained by reviewing medical records. Logistic regression analysis included calculation of univariate and multivariate (adjusted) odds ratios and 95% confidence intervals. RESULTS AND CLINICAL IMPLICATIONS: Dogs with fatal acute pancreatitis were largely middle- to older-aged dogs. Risk of developing fatal acute pancreatitis was increased by overweight body condition, diabetes mellitus, hyperadrenocorticism, hypothyroidism, prior gastrointestinal tract disease, and epilepsy. Additionally, Yorkshire Terriers were at increased risk, and Labrador Retrievers and Miniature Poodles were at decreased risk, of developing fatal acute pancreatitis. Males and neutered females appeared to have an increased risk of developing fatal acute pancreatitis, compared with sexually intact females. Thrombus formation was more likely in dogs that developed fatal acute pancreatitis than in control dogs.

A severity score for spontaneous canine acute pancreatitis

OBJECTIVE

To derive a severity score for spontaneous canine acute pancreatitis applicable to general practice.

DESIGN

Cohort study of canine pancreatitis cases.

PROCEDURE

Cases (n = 68) of spontaneous canine acute pancreatitis presented to general practitioners were identified among accessions to Veterinary Pathology Services Brisbane. The primary veterinarian was surveyed by telephone to ascertain the outcome of each case. Scores were assigned for extent of hyperamylasaemia, hyperlipasaemia and number of organ systems other than the pancreas compromised. The probability of mortality with each score of each analyte was calculated. The strength of interaction between scores for each analyte and mortality rate was assessed by chi-square analysis where appropriate. Relationships between the organ system score, other physiological variables and likelihood of euthanasia were analysed.

RESULTS

Scores derived mathematically from analysis of enzyme activities had poor abilities to predict mortality. The score based upon the number of organ systems compromised showed good ability to predict mortality and the interaction between the organ system score and mortality rate was significant by chi-square analysis (P < 0.01). Distribution of data within the amylase and lipase scores was not compatible with chi-square analysis.

CONCLUSION

Assessment of severity of spontaneous canine acute pancreatitis using pancreatic enzyme activities is potentially inaccurate. The use of a severity score based upon organ system compromise was more accurate in determining the likelihood of mortality in spontaneous canine acute pancreatitis. This is compatible with the hypothesis that severe canine acute pancreatitis is a multiple organ failure syndrome.

Endoscopic ultrasonographic findings of the pancreas after pancreatic duct ligation in the dog

Endoscopic ultrasonographic evaluation and gray-scale histogram analysis of pancreatic atrophy after pancreatic duct ligation were performed in four normal adult dogs. Using endoscopic ultrasonography, markedly dilated pancreatic ducts were visualized, and the pancreas became gradually atrophied with a hyperechoic parenchyma. In gray-scale histogram analysis of the pancreas, mean brightness increased gradually until 8 weeks, then decreased temporally. Standard deviation of the histogram increased markedly and then fluctuated until the 4th week, after which the mean brightness and standard deviation became stable. At 4 weeks postoperatively, collapse of most pancreatic acinar structures were observed, and each atrophic lobule was associated with a significantly large amount of interstitial fibrous tissue at histopathology. At 12 weeks postoperatively, most exocrine tissue had decreased and was partly replaced by fibrous and fatty tissue. These changes of mean brightness and standard deviation reflected the histologic analysis. These findings indicated that endoscopic ultrasonography is a useful technique to image such atrophic disorders of the pancreas as chronic pancreatitis. Furthermore, gray-scale histogram analysis provides helpful information for ultrasonographic tissue characterization of the pancreas.

Acute pancreatitis in chickens due to non-virulent Newcastle disease virus

A non-virulent Newcastle disease virus (strain APMV-1 96/89 VB) was isolated from a broiler chicken from a backyard flock. Using monoclonal antibodies, the virus was shown to be different from the vaccinal virus strains Hitchner, La Sota and Ulster. The virus was shown to replicate in the pancreas of one-day-old specific pathogen-free chickens infected orally, and the histological lesions observed in the pancreas of chickens inoculated with the fourth chicken passage of the virus five to nine days after infection were consistent with an acute pancreatitis.

Clinical, clinicopathologic, radiographic, and ultrasonographic abnormalities in dogs with fatal acute pancreatitis: 70 cases (1986-1995)

OBJECTIVE

To determine clinical, clinicopathologic, radiographic, ultrasonographic, and coagulation abnormalities in dogs in which acute pancreatitis was fatal.

DESIGN

Retrospective study.

ANIMALS

70 dogs.

PROCEDURE

History, clinical signs, and physical examination findings at the time of initial evaluation at the veterinary teaching hospital; results of pretreatment laboratory tests, abdominal radiography, and ultrasonography; and histologic abnormalities were obtained from medical records.

RESULTS

Clinical signs included anorexia, vomiting, Weakness, diarrhea, polyuria and polydipsia, neurologic abnormalities, melena, weight loss, hematemesis, and passage of frank blood in feces. At the time of initial examination at the veterinary teaching hospital, 68 (97%) dogs were dehydrated, 18 (26%) were icteric, 22 (32%) were febrile, 40 (58%) had signs of abdominal pain, and 30 (43%) were classified as overweight or obese. Most dogs had leukocytosis, neutrophilia with a left shift, and thrombocytopenia. Various serum biochemical abnormalities were identified, including hypoglycemia, azotemia, hypercalcemia and other electrolyte abnormalities, hypoalbuminemia, high hepatic and pancreatic enzyme activities, hypercholesterolemia, and lipemia. For 17 of 28 (61%) dogs, results of coagulation function tests were abnormal. Results of abdominal ultrasonography and radiography were consistent with a diagnosis of acute pancreatitis in 23 of 34 (68%) and 10 of 41 (24%) dogs, respectively. For 2 dogs, results of abdominal ultrasonography were not suggestive of acute pancreatitis, but results of abdominal radiography were.

CLINICAL IMPLICATIONS

Clinical signs and results of clinicopathologic tests are inconsistent. Abdominal ultrasonography may be valuable in the diagnostic evaluation of dogs suspected to have acute pancreatitis.

Endoscopic and transcutaneous ultrasonographic findings and grey-scale histogram analysis in dogs with caerulein-induced pancreatitis

Endoscopic ultrasonography (EUS), grey-scale histogram analysis of EUS images, and transcutaneous ultrasonography (TUS) were done in four dogs with caerulein-induced pancreatitis. One other dog was subjected to laparotomy and biopsy specimens were collected for histopathology. By EUS, the pancreatic lesions were first detected at 60 minutes after the start of caerulein infusion. They were detected after 120 to 150 minutes when using TUS. EUS findings included swelling, a more distinct lobular pattern, subcapsular hypoechoic areas, and anechoic stripes through the pancreatic tissue. No marked changes in the histogram analysis was seen until 30 minutes. From 30 to 60 minutes, a decrease in the mean brightness of the pancreatic tissue was observed. These changes in mean brightness reflected histopathological findings showing vacuolization of acinar cells and interstitial oedema of the pancreas. These findings indicated that EUS can detect slight and diffuse changes in pancreatic tissue. Furthermore, grey-scale histogram analysis detects histopathological changes more sensitively than endoscopic ultrasound images.

Pericolonic mass containing chyle as a presumed sequela to chronic pancreatitis in a dog

A 9-year-old dog was admitted because of recurrent episodes of chronic pancreatitis. Ultrasonography revealed a multiloculated, fluid-filled cystic mass at the caudal portion of the stomach. Guided fine-needle aspirates yielded a fluid consistent with chyle. The dog underwent surgery during which a 6- to 8-cm mass was found adhered to the mesocolon and serosa of the transverse colon. Intraoperative lymphangiography revealed lymphangiectasia, but contrast medium did not accumulate within the mass. The mass and a portion of transverse colon were removed en bloc. Results of histologic examination were consistent with an abscess. Pancreatic enzymatic digestion may allow abscesses to extend beyond pancreatic parenchyma, cause severe local inflammation, and encapsulate and incorporate adjacent abdominal lymphatics. Subsequent lymphatic leakage can result in chyle within the abscess. Inflammatory masses of the pancreas are a rare, but serious, complication of pancreatitis in dogs. Familiarity with these types of lesions can aid in selection of appropriate treatments.