Comparison of Serum Spec fPL(™) and 1,2-o-Dilauryl-Rac-Glycero-3-Glutaric Acid-(6'-Methylresorufin) Ester Assay in 60 Cats Using Standardized Assessment of Pancreatic Histology

Evaluation of Disease Spectrum in Hospitalized Cats with Hyperlipasemia: Pancreatitis Alone Is Rare, Hyperlipasemia without Suspected Pancreatitis Is Common

Histological evidence of pancreatitis is commonly found in necropsy studies in cats. A clinical diagnosis of pancreatitis is challenging due to nonspecific clinical signs, a lack of diagnostic lipase cutoffs, and frequent presence of multiple diseases. It is still unknown how often pancreatitis alone is found in sick cats and how often clinicopathological evidence of pancreatitis in sick cats does not lead to a clinical diagnosis of pancreatitis. Our aims were to evaluate the extent of comorbidities in cats with suspected pancreatitis, evaluate how often sick cats with hyperlipasemia are diagnosed only with non-pancreatic diseases, and compare their clinical findings. Medical records of 563 client-owned hospitalized cats with available lipase activity measurement (LIPC Roche) > 30 U/L (RI, 6-26) were searched and medical diagnoses recorded and grouped by organ system. Clinicopathological findings were compared between cats with pancreatitis alone (PA), pancreatitis with concurrent disease (PD), and no suspected pancreatitis (NP). We found that PA was present in 33 (6%) cats, 159 cats (28%) were in the PD group, and 371 cats (66%) had no suspected pancreatitis (NP). Clinical, laboratory, and ultrasonographic findings did not differ between PA and PD cats. Lipase activities did not differ between the three groups. The most common disease categories in PD and NP cats were gastrointestinal, hepatobiliary, renal/urinary, and endocrine, and renal/urinary, gastrointestinal, cardiac, and musculoskeletal, respectively. We conclude that cats are rarely hospitalized because of suspected pancreatitis alone, and PA cats did not differ clinically from PD cats. Hyperlipasemia in sick cats without a diagnosis of pancreatitis may be due to a reactive pancreatopathy or preexisting chronic pancreatitis.

Effects of prednisolone on 1,2-O-dilauryl-rac-glycero glutaric acid-(60-methylresorufin) ester-lipase activity and pancreatic lipase immunoreactivity in healthy cats

BACKGROUND

Corticosteroids are among the most commonly used drugs in cats and are increasingly discussed as a treatment for feline pancreatitis. However, its effects on serum lipase in healthy cats remain unknown.

OBJECTIVES

To evaluate the effects of prednisolone on serum lipase activity and pancreatic lipase immunoreactivity (PLI) in cats.

ANIMALS

Seven clinically healthy colony cats, aged 4 to 7 years, with unremarkable CBC/biochemistry panel were studied.

METHODS

Prospective study: Prednisolone (1.1-1.5 mg/kg, median 1.28 mg/kg PO) was given daily for 7 consecutive days. Lipase activity (LIPC Roche; RI, 8-26 U/L) and PLI (Spec fPL; RI, 0-3.5 μg/L) were determined at day 1 before first treatment and at days 2, 3, 8, 10, and 14. Cats were examined daily. An a priori power analysis indicated that 6 cats were needed to find a biological relevant effect at 1-β = 0.8. Statistical analyses comprised the Friedman test, random intercept regression, and repeated-measures linear regression.

RESULTS

Median (range) day 1 lipase activities and PLI were 22 U/L (14-52 U/L) and 3.2 μg/L (2.3-15.7 μg/L). One cat with abnormally high lipase activity (52 U/L) and PLI (15.7 μg/L) at day 1 continued having elevated lipase activities and PLI throughout the study. Lipase activities and PLI concentrations did not differ significantly among time points regardless of whether the cat with elevated values was included or not. All cats remained healthy throughout the study.

CONCLUSIONS AND CLINICAL IMPORTANCE

Administration of prednisolone in anti-inflammatory doses does not significantly increase serum lipase activity and PLI concentration.

Clinical enzymology of the dog and cat

Clinical enzymology studies the enzyme activity in serum or other body fluids for the diagnosis, prognosis or monitoring of a variety of diseases. Clinical enzymology has greatly benefited from advances in technology and is now an integral part of laboratory analysis. However, to maximise the clinical benefits of serum enzyme measurement, clinicians and clinical pathologists must have a good understanding of the pathophysiology behind serum enzyme alterations. They must also be aware of the preanalytical and analytical factors that can affect the accuracy of serum enzyme activity measurement. This review article first covers the basic concepts of clinical enzymology and the general mechanisms related to serum enzyme alterations. Then, the review discusses the potential effects of various preanalytical and analytical factors on enzyme activity measurement. Lastly, it explores the pathophysiology and clinical use of various serum enzymes in canine and feline medicine. The present review article aims to be a comprehensive one-stop source for clinical pathologists and small animal practitioners.

Analytical validation of an ELISA for the measurement of feline pancreas-specific lipase and re-evaluation of the reference interval and decision threshold for diagnosing pancreatitis

BACKGROUND

The diagnosis of feline pancreatitis can be challenging. The clinical presentation often includes mild, nonspecific clinical signs, such as vomiting, anorexia, and weight loss. Measurement of feline pancreatic lipase immunoreactivity (fPLI) concentration in serum has been reported to be sensitive and specific for a diagnosis of pancreatitis in cats. However, analytical validation for a widely available commercial assay for the measurement of fPLI concentration has not been published.

OBJECTIVE

We aimed to analytically validate the Spec fPL assay (IDEXX Laboratories, Westbrook, ME), a commercial ELISA for the measurement of fPLI concentration, and re-evaluate its reference interval and decision threshold for diagnosing pancreatitis in cats.

METHODS

Dilutional linearity, accuracy, precision, and the effect of interfering substances were assessed. The upper limit of the reference interval was calculated based on the 95th percentile of results from clinically healthy cats (n = 107), and a decision threshold for diagnosing pancreatitis was calculated with an expected specificity of 99%.

RESULTS

Analytical validation demonstrated good linearity, accuracy, and precision, as well as the absence of interference from lipemia, hemolysis, or icterus. The upper limit of the reference interval for Spec fPL was determined to be 4.4 μg/L, and the decision threshold (a theoretical cut-off) for diagnosing pancreatitis was determined to be 8.8 μg/L based on a desired specificity of 99%.

CONCLUSIONS

The Spec fPL assay is analytically valid, and results suggest that a decision threshold of 8.8 μg/L would have high diagnostic specificity for excluding clinically healthy cats.

Specificity of a pancreatic lipase point-of-care test and agreement with pancreatic lipase immunoreactivity in cats without clinical evidence of pancreatitis

OBJECTIVES

The aim of this study was to determine the specificity of a rapid point-of-care test for the estimation of feline pancreatic lipase (SNAP fPL) in healthy and sick cats without clinical evidence of pancreatitis. A second objective was to evaluate the agreement between SNAP fPL and serum pancreatic lipase immunoreactivity (fPLI), as measured by Spec fPL.

METHODS

A total of 150 cats were prospectively enrolled into this study. Of them, 82 cats were healthy while 68 cats had various diseases but no clinical signs (eg, anorexia, depression, vomiting) raising a suspicion of pancreatitis.

RESULTS

SNAP fPL was normal in 133/150 cats (specificity 89%) without obvious clinical pancreatitis. SNAP fPL was normal in 74/82 healthy cats (specificity 90%) and in 59/68 cats that were sick but without typical signs of pancreatitis (specificity 87%). The agreement between SNAP fPL and Spec fPL was substantial (k = 0.64) in healthy cats and almost perfect (k = 0.93) in sick cats. The overall agreement between SNAP fPL and Spec fPL was almost perfect (k = 0.81).

CONCLUSIONS AND RELEVANCE

The specificity of SNAP fPL in this group of cats was high. There was a substantial and almost perfect agreement between the SNAP fPL and Spec fPL in healthy cats and sick cats without suspected pancreatitis, respectively. In the small percentage of cats with abnormal SNAP fPL and/or Spec fPL results, the possibility of subclinical pancreatitis cannot be excluded.

Progression of lipase activity and pancreatic lipase immunoreactivity in dogs hospitalized for acute pancreatitis and correlation with clinical features

BACKGROUND

Lipase activity and pancreatic lipase immunoreactivity (PLI) have not been compared in dogs hospitalized for acute pancreatitis (AP).

OBJECTIVES

To describe the progression of lipase activity and PLI, and correlations with clinicopathologic features in dogs with AP.

ANIMALS

Thirty-nine dogs with AP based on clinical signs and lipase activity >350 U/L (reference interval [RI], 24-108 U/L).

METHODS

Retrospective study. Lipase activity (LIPC Roche), PLI (SpecPL), and clinical signs were recorded daily. Admission (d1) data (clinical, laboratory, and ultrasound [US] findings), and clinical signs during hospitalization (d2-d3) were assessed for correlation with lipases.

RESULTS

Median (range) duration of clinical signs before presentation was 2 days (1-7 days). Median (range) lipase activity and PLI at d1 were 1070 U/L (range, 357-1500 U/L) and 1111 μg/L (range, 292-1500 μg/L). Strong correlation between assays at d1 (r_s 0.96; P < .0001; n = 39), remained equally strong on d2 (r_s 0.964; P < .0001; n = 39), and d3 (r_s 0.966; P < .0001; n = 22). On d2, lipase activity and PLI were within RI in 13/39 (33%) and 18/39 (46%) of cases. Lipase activities were minimally increased (median, 124 U/L) in 5 dogs with d2 PLI <200 μg/L. On d3, 4 more dogs had normal lipase activity and PLI, and the nature and magnitude of change were always the same for both assays. Clinical signs were not associated with lipases. Only a hyperechoic mesentery, but not an US diagnosis of AP, correlated significantly with lipase activity and PLI.

CONCLUSIONS AND CLINICAL IMPORTANCE

Lipase decreases rapidly to near or within RI within 2 days of treatment in the majority of dogs with AP. Both lipase assays yielded virtually identical results. Mesenteric echogenicity may be an early marker of AP in dogs.

Feline Comorbidities: Clinical perspective on diabetes mellitus and pancreatitis

PRACTICAL RELEVANCE

Diabetes mellitus (DM) is one of the most common feline endocrine disorders. It has been shown by several studies that DM in cats frequently coexists with pancreatitis.

CLINICAL CHALLENGES

It has not been definitively established what the exact pathogenetic association between DM and pancreatitis is in the cat. However, the association between these two conditions is most likely bidirectional, with DM predisposing cats to pancreatitis and vice versa. Diagnosis of pancreatitis in cats with DM is crucial because concurrent pancreatitis commonly leads to difficulties in the management of DM. When pancreatitis is associated with diabetic ketoacidosis (DKA), therapeutic management is even more challenging.

AIMS

This review focuses on the concurrent presence of DM or DKA and pancreatitis in cats, mainly focusing on their clinical management.

EVIDENCE BASE

Information provided in this review is based on feline-specific clinical research when available. In addition, comparative and human research, as well as clinical experience, has been used to enrich knowledge in areas where feline-specific research is not yet available.

Accuracy of acute-phase proteins in identifying lethargic and anorectic cats with increased serum feline pancreatic lipase immunoreactivity

The mainstay of laboratory diagnostics of feline pancreatitis (FP) is measuring serum feline pancreatic lipase immunoreactivity (fPLI). Thus far, several studies have investigated the relationship between acute-phase proteins (APPs) and the presence and severity of FP. Although changes in serum amyloid A (SAA) concentration have been linked with FP, its diagnostic accuracy remains unknown. We aimed to determine the accuracy of selected APPs in identifying cats with a high risk of FP based on increased fPLI. Serum fPLI was measured in cats (n = 52) that were presented to veterinary clinics with signs of lethargy and anorexia. The cats were divided into two groups (fPLI ≤3.5 μg/L; n = 27 and fPLI >3.5 μg/L, n = 25), corresponding to low and high risks of FP. Serum albumin, globulin, haptoglobin (Hp), and SAA concentrations, as well as the albumin-to-globulin ratio (A/G) and SAA-to-albumin (SAA/A) ratios, were determined and compared between groups. The accuracy of these measurements was examined using a multivariable logistic regression model and receiver operator characteristic (ROC) curve analysis. SAA concentrations and SAA/A ratios were significantly (P = .026 and P = .022) higher in cats with increased fPLI, with the area under ROC curve (AUROC) of 68.1% (CI 95%: 53.4%, 82.9%) and 68.6% (CI 95%: 54.0%, 83.2%), respectively. The logistic regression model combining SAA and A/G had AUROC of 75.2% (CI 95%: 62.0%, 88.4%) for identifying cats with increased fPLI. SAA as a sole analyte or combined with A/G had low to moderate accuracy in identifying anorexic, lethargic cats with increased fPLI. Serum albumin, globulin, and Hp concentrations had no discriminatory potential in these cats.

Correlation between metabolomic profile constituents and feline pancreatic lipase immunoreactivity

Background

Feline pancreatic lipase immunoreactivity (fPLI) is commonly used to diagnose pancreatitis in cats (FP). Untargeted metabolomics has been extensively applied in human and veterinary medicine, but no metabolomic studies regarding FP have been conducted.

Objectives

To identify metabolites significantly associated with increased fPLI.

Animals

Forty‐nine client‐owned cats: 11 clinically healthy and 38 with various clinical conditions.

Methods

Analytical cross‐sectional study with convenience sampling. A panel of 630 metabolites belonging to 26 biochemical classes was quantified in plasma using a commercial metabolomic assay. The correlation between plasma metabolite concentrations and serum fPLI was evaluated using Spearman's rank correlation coefficient (R_s) with Bonferroni correction. Multivariable analysis then was performed to control for glomerular filtration rate, liver damage, and blood glucose concentration. The accuracy of selected metabolites in discriminating between cats with normal (≤3.5 μg/L) and increased (>5.3 μg/L) fPLI was estimated using the area under the receiver operating characteristic curve (AUROC).

Results

Four hundred and seven of 630 metabolites (64.6%) were quantified in all cats. When controlled for potential confounders only 3 sphingolipids were significantly positively correlated with fPLI: 2 cerebrosides: HexCer(d18:1/24:0); (R_s = .56), and HexCer(d18:1/24:1); (R_s = .58) and 1 sphingomyelin: SM C18:0 (R_s = .55). Their AUROCs in identifying cats with increased fPLI were 82% (95% confidence interval [CI 95%], 70%‐94%), 84% (CI 95%, 72%‐96%), and 78% (CI 95%, 65%‐92%), respectively.

Conclusions and Clinical Importance

Selected sphingolipids are moderately positively correlated with fPLI and appear to have fair to moderate diagnostic accuracy in discriminating between cats with normal and increased fPLI.

Application of a complete blood count to screening lethargic and anorectic cats for pancreatitis

Background

Feline pancreatitis (FP) is an important health problem of cats. Its diagnostics is based on the combination of quantification of serum pancreatic lipase immunoreactivity (fPLI) and abdominal ultrasonography (AUS). These modalities allow for establishing highly specific diagnosis, however they are relatively expensive and time-consuming. On the other hand, a screening test of high sensitivity which would allow to rule out FP on the first visit without a considerable increase of costs would be clinically useful. To evaluate accuracy of nonspecific inflammatory biomarkers based on complete blood count (CBC) in diagnosing FP 73 client-owned cats with signs of lethargy and reduced appetite lasting for at least 2 days before presentation were enrolled in the cross-sectional study. They were examined with fPLI assay and AUS and classified as cats with very low risk of FP when fPLI ≤3.5 μg/L and AUS negative for FP, or as cats with increased risk of FP in the case of any other combination of results. Then, 7 various CBC measurements were measured in each cat and linked to the risk of FP using the multivariable logistic regression.

Results

Five CBC measurements turned out to be significantly associated with the risk of FP – total leukocyte count (WBC; crude odds ratio(OR_crude) = 12.2; CI 95%: 1.52, 98.5), total neutrophil count (OR_crude = 5.84; CI 95%: 1.22, 27.9), band neutrophil count (BNC; OR_crude = 6.67; CI 95%: 1.98, 22.4), neutrophil-to-lymphocyte ratio (OR_crude = 3.68; CI 95%: 1.25, 10.9), and eosinophil count (EC; OR_crude = 0.34; CI 95%: 0.12, 0.96). The model based on WBC, BNC, and EC proved to have at least fair diagnostic potential (area under ROC curve 82.7%; CI 95%: 72.8%, 92.5%). When WBC <  18 G/L, BNC <  0.27 G/L, and EC >  0.3 G/L was considered as a negative result, and any other combination as the positive result, the CBC model had high sensitivity (91.8%; CI 95%: 80.8%, 96.8%) at a relatively low specificity (58.3%; CI 95%: 38.8%, 75.5%).

Conclusion

The combination of three CBC measurements is an immediately available and fairly accurate screening method for identification of lethargic and anorectic cats with increased risk of FP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-03098-z.

The Agreement between Feline Pancreatic Lipase Immunoreactivity and DGGR-Lipase Assay in Cats-Preliminary Results

Simple Summary

Feline pancreatitis is a common disease with diagnostics requiring a combination of clinical, laboratory and imaging methods. Measuring of pancreatic lipase concentration is the laboratory mainstay of feline pancreatitis diagnostics. It can be done using immunoenzymatic assay (feline pancreatic immunoreactivity, fPLI) or colorimetric assay based on hydrolyzing a special substrate (DGGR) to a color product. A DGGR-lipase assay is manufactured by various companies. Studies carried out in cats on the DGGR-lipase assay of a single manufacturer have shown a high agreement with fPLI, however studies in dogs indicate that the performance of assays of different manufacturers may vary considerably. One of the largest Polish veterinary laboratories working 24/7 in the largest Polish cities offers the DGGR-lipase assay of a large Polish laboratory solutions provider. The values obtained in this assay are higher than those yielded by the traditional DGGR-lipase assay validated in studies carried out so far. Therefore, we decided to evaluate the agreement between the DGGR-lipase assay of the Polish manufacturer and fPLI. The agreement proved to be as high as for the traditional assay.

Abstract

The colorimetric catalytic assay based on the use of 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6′-methylresorufin) (DGGR) ester as a substrate for pancreatic lipase activity is commonly used for the diagnosis of pancreatitis in dogs and cats. Even though the assay has generally been shown to yield consistent results with feline pancreatic lipase immunoreactivity (fPLI) assay, the agreement may vary between assays of different manufacturers. In this study, the chance-corrected agreement between a DGGR-lipase assay offered by one of the biggest providers of diagnostic solutions in Poland and fPLI assay was investigated. The study was carried out on 50 cats in which DGGR-lipase activity and fPLI were tested in the same blood sample. The chance-corrected agreement was determined using Gwet’s AC₁ coefficient separately for the fPLI assay’s cut-off values of >3.5 μg/L and >5.3 μg/L. The DGGR-lipase activity significantly positively correlated with fPLI (R_s = 0.665; CI 95%: 0.451, 0.807, p < 0.001). The chance-corrected agreement between the fPLI assay and DGGR-lipase assay differed considerably depending on the cut-off values of the DGGR-lipase assay. When the cut-off value reported in the literature (>26 U/L) was used, it was poor to fair. It was moderate at the cut-off value recommended by the laboratory (>45 U/L), and good at the cut-off value recommended by the assay’s manufacturer (>60 U/L). The highest agreement was obtained between the fPLI assay at the cut-off value of 3.5 μg/L and the DGGR-lipase assay at the cut-off value of 55 U/L (AC₁ = 0.725; CI 95%: 0.537, 0.914) and between the fPLI assay at the cut-off value of 5.3 μg/L and the DGGR-lipase assay at the cut-off value of 70 U/L (AC₁ = 0.749; CI 95%: 0.577, 0.921). The study confirms that the chance-corrected agreement between the two assays is good. Prospective studies comparing both assays to a diagnostic gold standard are needed to determine which of them is more accurate.

ACVIM consensus statement on pancreatitis in cats

Background

Pancreatitis in cats, although commonly diagnosed, still presents many diagnostic and management challenges.

Objective

To summarize the current literature as it relates to etiology, pathogenesis, diagnosis, and management of pancreatitis in cats and to arrive at clinically relevant suggestions for veterinary clinicians that are based on evidence, and where such evidence is lacking, based on consensus of experts in the field.

Animals

None.

Methods

A panel of 8 experts in the field (5 internists, 1 radiologist, 1 clinical pathologist, and 1 anatomic pathologist), with support from a librarian, was formed to assess and summarize evidence in the peer reviewed literature and complement it with consensus clinical recommendations.

Results

There was little literature on the etiology and pathogenesis of spontaneous pancreatitis in cats, but there was much in the literature about the disease in humans, along with some experimental evidence in cats and nonfeline species. Most evidence was in the area of diagnosis of pancreatitis in cats, which was summarized carefully. In contrast, there was little evidence on the management of pancreatitis in cats.

Conclusions and Clinical Importance

Pancreatitis is amenable to antemortem diagnosis by integrating all clinical and diagnostic information available, and recognizing that acute pancreatitis is far easier to diagnose than chronic pancreatitis. Although both forms of pancreatitis can be managed successfully in many cats, management measures are far less clearly defined for chronic pancreatitis.

The 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester (DGGR) lipase assay in cats and dogs is not specific for pancreatic lipase

BACKGROUND

The measurement of pancreatic lipase is important for the diagnosis of feline and canine pancreatitis. Recent studies have claimed that lipase assays using the 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester (DGGR) as a substrate are more specific for measuring pancreatic lipase than traditional lipase assays. However, the analytical specificity of this assay for pancreatic lipase has not been demonstrated.

OBJECTIVES

We aimed to determine whether hepatic and/or lipoprotein lipases can interfere with the DGGR-based assay results in cats and dogs. We, therefore, compared plasma lipase activities measured using DGGR-based and pancreatic lipase immunoreactivity (PLI) assays before and after administering heparin, known to cause the release of hepatic and lipoprotein lipases, in cats and dogs.

METHODS

Heparin was administered in six cats and six dogs. Blood was collected at baseline and 10, 20, 30, 60, and 120 minutes after heparin administration. Lipase activity was measured using a DGGR-based assay, and PLI concentrations were measured using the Spec fPL and cPL assays for cats and dogs, respectively.

RESULTS

Plasma lipase activities, as measured using the DGGR-based assay, increased significantly 10 minutes after heparin administration in both cats (P = .003) and dogs (P = .006) and returned to baseline by 120 minutes. In contrast, PLI concentrations showed no significant changes after heparin administration.

CONCLUSIONS

DGGR is not only hydrolyzed by pancreatic lipase but also by hepatic lipase, lipoprotein lipase, or both, in cats and dogs. Since these extrapancreatic lipases are also naturally present in cats and dogs, they could contribute to the lack of analytical specificity for the DGGR-based assays.

Efficacy of intramuscular hydroxocobalamin supplementation in cats with cobalamin deficiency and gastrointestinal disease

Background

In humans, absorption and tissue retention rates of intramuscularly administered hydroxocobalamin (OH‐Cbl) are superior compared to cyanocobalamin (CN‐Cbl). Supplementation with OH‐Cbl has not been described in cats.

Objectives

To evaluate effects of parenteral OH‐Cbl supplementation on clinical signs, serum Cbl and methylmalonic acid (MMA) concentrations in hypocobalaminemic cats with gastrointestinal disease.

Animals

Twenty‐three client‐owned cats.

Methods

Prospective study. Serum Cbl and MMA concentrations were determined at enrollment (t0), immediately before the 4th OH‐Cbl IM injection (300 μg, given q2 weeks) (t1), and 4 weeks after the 4th injection (t2). Severity of clinical signs (activity, appetite, vomiting, diarrhea, body weight) was graded at each time point and expressed as clinical disease activity score.

Results

Median clinical disease activity score decreased significantly from t0 (6; range, 2‐10) to t1 (1; range, 0‐6) and t2 (1; range, 0‐9). Median serum Cbl concentration increased significantly from 111 pmol/L (range, 111‐218; reference range, 225‐1451 pmol/L) at t0 to 1612 pmol/L (range, 526‐14 756) (P < .001) at t1, and decreased again significantly to 712 pmol/L (range, 205‐4265) (P < .01) at t2. Median baseline serum MMA concentration at t0 (802 nmol/L; range, 238‐151 000; reference range, 120‐420 nmol/L) decreased significantly (P < .001) to 199 nmol/L (range, 29‐478) at t1, and was 205 nmol/L (range, 88‐734) at t2. Serum MMA concentrations normalized in 22/23 cats at t1, and were not significantly higher at t2 compared to t1.

Conclusions and Clinical Importance

The herein described OH‐Cbl injection scheme appears efficacious for normalization of cellular Cbl deficiency in cats with gastrointestinal disease.

Is It Being Overdiagnosed? Feline Pancreatitis

In recent years, increased awareness of feline pancreatitis by the veterinary profession and improved diagnostic modalities have led to an increased frequency of diagnosis of pancreatitis in this species. Consequently, pancreatic diseases, especially chronic pancreatitis, are considered highly prevalent, even in populations of apparently healthy individuals. This prevalence has led to the suspicion that the condition may be overdiagnosed. This article summarizes the difficulties of diagnosis of acute and chronic pancreatitis, assesses the reasons why this is a challenging disease to recognize, and considers whether these difficulties could result in either overdiagnosis or underdiagnosis.

Evaluation of 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester lipase concentrations in cats with kidney disease and with normal SNAP fPL

Measuring 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester (DGGR) lipase activity is a cost-effective test for diagnosing pancreatitis compared to the feline pancreas-specific lipase (Spec fPL) test. However, little is known about the influence of renal insufficiency on DGGR lipase in cats. This study evaluated the influence of renal function on serum DGGR lipase in the cat. Serum samples from 49 cats with normal pancreas-specific lipase immunoreactivity were analyzed for DGGR lipase activity and serum creatinine. Median serum DGGR lipase activity for cats with kidney disease (KD+) was 22 IU/L (range: 9 to 29 IU/L), whereas for cats without kidney disease (KD-) and healthy cats, the medians were 16 IU/L (range: 6 to 32 IUI/L), and 15 IU/L (range: 9 to 23 IU/L), respectively. The KD+ group had significantly higher DGGR lipase concentrations compared to the healthy group (P = 0.030), but most results were within the reference range. There was a weak positive correlation between creatinine and DGGR lipase values (R 2 = 19.6%; P = 0.0014) and no significant correlation between symmetric dimethylarginine (SDMA) and DGGR lipase. Key clinical message: Although cats with kidney disease had significantly higher serum DGGR lipase concentrations than the healthy controls, the difference was small and does not appear to be clinically relevant.

Retrospective study of the diagnostic utility of Spec fPLin the assessment of 274 sick cats

Background

Serum feline pancreatic lipase immunoreactivity (fPL) commonly is used in the assessment of sick cats suspected to have pancreatitis but its diagnostic utility is debated.

Objectives

To evaluate the diagnostic utility of the Spec fPL test and selected serum biochemistry tests in the diagnosis of pancreatitis in cats.

Animals

Two hundred seventy‐four client‐owned cats presented to a university teaching hospital in the United Kingdom, from April 2013 to May 2017, in which Spec fPL was measured.

Methods

Cats were classified into 1 of 4 groups based on clinical signs (all cats), ultrasonographic findings (all cats) and histopathological or cytological assessment of the pancreas where available (9 cats) regardless of Spec fPL concentration. The groups were (a) definite pancreatitis (n = 9), (b) probable pancreatitis (n = 49), (c) possible pancreatitis (n = 139), and (d) unlikely pancreatitis (n = 77). Spec fPL and selected serum biochemistry test results were compared among groups.

Results

Serum fPL concentrations >5.3 μg/L were classified as positive and concentrations <3.5 μg/L were classified as negative. There was a significantly (P = .03) lower proportion of false‐positive results (cats unlikely to have pancreatitis, n = 77, with a positive fPL, n = 8, 10%) than false‐negative results (cats with definite or probable pancreatitis, n = 58, with a negative fPL result, n = 14, 24%). None of the selected biochemical tests were helpful diagnostically.

Conclusion and Clinical Importance

A positive Spec fPL result indicates that pancreatitis is a probable diagnosis, but the test cannot be used to rule the diagnosis out.

Histopathology and Feline Pancreatic Lipase Immunoreactivity in Inflammatory, Hyperplastic and Neoplastic Pancreatic Diseases in Cats

The most common pancreatic diseases in cats are pancreatitis and exocrine pancreatic insufficiency (EPI). Non-invasive methods, such as serological quantification of feline pancreatic lipase immunoreactivity (fPLI), are often used in the diagnosis of pancreatitis. Previous studies have compared fPLI concentrations with histopathology, considered to be the gold standard for diagnosis of feline pancreatitis. However, fPLI concentrations in cats suffering from pancreatic tumours were rarely described. The aim of the present study was to determine the sensitivity and specificity of an in-house enzyme-linked immunosorbent assay (ELISA) for the quantification of fPLI in serum samples based on histopathological findings in cats diagnosed with various pancreatic diseases. Pancreatic biopsy samples from 80 cats were included. Five groups were defined on the basis of pancreatic histopathology: group 1, normal pancreas; group 2, nodular hyperplasia; group 3, mild pancreatitis; group 4, marked (moderate/severe) pancreatitis; and group 5, pancreatic neoplasia. Serum samples from all cats were tested by fPLI ELISA (<3.6 μg/l normal, 3.6-5.3 μg/l questionable, >5.3 μg/l pancreatitis). In group 1 (n = 19), serum fPLI values were within the reference interval in 74% of cases and in group 2 (n = 9) in 78%. Cats with mild pancreatitis (n = 23), marked pancreatitis (n = 11) and pancreatic neoplasms (n = 18) had significantly increased fPLI concentrations compared with group 1 (P = 0.004/0.001/≤0.0001). Cats with nodular hyperplasia had significantly lower fPLI values than cats with marked pancreatitis (P = 0.048) or tumours (P = 0.002). Serum fPLI concentrations in group 3 were <3.6 μg/l (n = 6), 3.6-5.3 μg/l (n = 4) and >5.3 μg/l (n = 13). Calculated test sensitivity for mild pancreatitis was fPLI >3.5 μg/l: 73.9% and fPLI >5.3 μg/l: 56.5%. In group 4 (n = 11), seven of nine cats (77.8%) with marked purulent pancreatitis had elevated fPLI. In group 4, a sensitivity of 81.8% was detected for fPLI >3.5 μg/l and 63.6% for fPLI >5.3 μg/l. Two cats with marked non-purulent pancreatitis had elevated fPLI, while two cats with marked purulent pancreatitis had normal fPLI values (<3.6 μg/l). In group 5, one cat with pancreatic adenoma and one with pancreatic acinar carcinoma had normal fPLI concentrations. The other cats with pancreatic adenoma (solid, n = 1; cystic, n = 4) or carcinoma (solid, n = 9; cystic, n = 2) had elevated or high fPLI values (4.1 to >40 μg/l, median 21.2 μg/l), probably caused by additional inflammation. The results of the present study confirm the importance of detailed histopathological characterization for the interpretation of clinical signs and fPLI values in feline pancreatitis. Primary pancreatic neoplasms may also lead to elevated fPLI concentrations as there is concurrent pancreatitis in most cases. However, severe pancreatic diseases, such as chronic non-purulent pancreatitis or tumours without inflammation, may result in normal fPLI values.

Effects of 6 Weeks of Parenteral Cobalamin Supplementation on Clinical and Biochemical Variables in Cats with Gastrointestinal Disease

Background

Effects and duration of commonly used protocols for cobalamin (Cbl) supplementation on cellular Cbl deficiency have not been determined in hypocobalaminemic cats.

Hypothesis/Objectives

To evaluate effect of Cbl supplementation on clinical signs, serum and urine methylmalonic acid (MMA) concentrations over 16 weeks.

Animals

Twenty client‐owned hypocobalaminemic cats with enteropathy.

Methods

Prospective study. Serum Cbl and serum and urine MMA concentrations were determined prospectively in cats at enrollment (t0), immediately before (t6), and 4 (t10) and 10 weeks (t16) after 6th Cbl injection (250 μg, IM q 7 days). Clinical signs severity (activity, appetite, vomiting, diarrhea, body weight) graded at each time point and expressed as clinical disease activity score.

Results

Clinical disease activity score decreased during supplementation and increased after treatment discontinuation. Median serum Cbl concentration increased significantly from t0 (111 pmol/L, range 111–212) to t6 (2,332.5 pmol/L, range 123–22,730) (P < 0.01). Values at t10 were 610.5 pmol/L (range, 111–2,527) and 180.5 pmol/L (range, 111–2,262) at t16 (P < 0.01). Median baseline serum MMA concentration (372 μmol/L, range 0.39–147,000) decreased significantly to 1.62 μmol/L (range, 0.18–806) at t6 (P < 0.01) and gradually increased to 5.34 μmol/L (range, 0.13–1,730) at t10 and 189 μmol/L (range, 0.4–983) at t16. Similar, nonsignificant, pattern observed for urine MMA concentration. Serum and urine MMA concentrations had not normalized in 12 and 6 cats, respectively, at t6.

Conclusion and Clinical Importance

The Cbl supplementation protocol used here did not lead to complete normalization of cellular Cbl deficiency in all examined cats, and biochemical improvements were transient.

Expression profiling feline peripheral blood monocytes identifies a transcriptional signature associated with type two diabetes mellitus

Diabetes mellitus is a common disease of cats and is similar to type 2 diabetes (T2D) in humans, especially with respect to the role of obesity-induced insulin resistance, glucose toxicity, decreased number of pancreatic β-cells and pancreatic amyloid deposition. Cats have thus been proposed as a valuable translational model of T2D. In humans, inflammation associated with adipose tissue is believed to be central to T2D development, and peripheral blood monocytes (PBM) are important in the inflammatory cascade which leads to insulin resistance and β-cell failure. PBM may thus provide a useful window to study the pathogenesis of diabetes mellitus in cats, however feline monocytes are poorly characterised. In this study, we used the Affymetrix Feline 1.0ST array to profile peripheral blood monocytes from 3 domestic cats with T2D and 3 cats with normal glucose tolerance. Feline monocytes were enriched for genes expressed in human monocytes, and, despite heterogeneous gene expression, we identified a T2D-associated expression signature associated with cell cycle perturbations, DNA repair and the unfolded protein response, oxidative phosphorylation and inflammatory responses. Our data provide novel insights into the feline monocyte transcriptome, and support the hypothesis that inflammatory monocytes contribute to T2D pathogenesis in cats as well as in humans.

SNAP Tests for Pancreatitis in Dogs and Cats: SNAP Canine Pancreatic Lipase and SNAP Feline Pancreatic Lipase

A clinical diagnosis of pancreatitis in dogs and cats can be challenging. Several diagnostic modalities have been evaluated over the years for the diagnosis of canine and feline pancreatitis, but most of these modalities have been shown to be of limited clinical use because of poor performance, limited availability, or because they are invasive, or all of these. Assays for the measurement of pancreatic lipase (PL) immunoreactivity [Specific canine PL (Spec cPL) in dogs and Specific feline PL (Spec fPL) in cats] were first developed approximately 15 years ago, and studies have shown that they are currently the serum tests of choice for the evaluation of canine and feline patients, respectively, suspected of having pancreatitis. This is a direct consequence of their high specificity of detecting only PL and their sensitivity for pancreatitis when compared with other serum tests. SNAP cPL and SNAP fPL are in-clinic tests that have been developed based on the Spec cPL and Spec fPL assays. As with any other test, false-positive and false-negative results do occur with PL immunoreactivity assays, and it is important to know the limitations of these assays.

Evaluation of insulin-like growth factor-1, total thyroxine, feline pancreas-specific lipase and urinary corticoid-to-creatinine ratio in cats with diabetes mellitus in Switzerland and the Netherlands

Objectives

The aim of the study was to evaluate circulating insulin-like growth factor-1 (IGF-1), feline pancreas-specific lipase (fPLI) and total thyroxine (TT4) concentrations and urinary corticoid-to-creatinine ratio (UCCR) as indicators for the prevalence of acromegaly, pancreatitis, hyperthyroidism and hypercortisolism in cats with diabetes mellitus.

Methods

Blood and urine samples were collected from diabetic cats treated in primary care clinics in Switzerland and the Netherlands. Standardised questionnaires and physical examination forms provided clinical information from owners and veterinarians. Laboratory testing included serum biochemistry profile analysis and measurement of circulating fructosamine, IGF-1, fPLI, and TT4 concentrations and UCCR. CT of the pituitary gland was performed using a multidetector computed tomography scanner.

Results

Blood samples were available from 215 cats and urine samples were collected at home from 117 cats. Age ranged from 2–18 years (median 12 years) and body weight from 2.7–12.3 kg (median 5.5 kg). Sixty-five percent of the cats were castrated male and 35% were female (33% spayed); 82% were domestic shorthair cats. Eighty percent of cats received a porcine insulin zinc suspension, 19.5% insulin glargine and 0.5% a human neutral protamine hagedorn insulin. Thirty-six of 202 (17.8%) cats had IGF-1 concentrations >1000 ng/ml. Serum fPLI, and TT4 concentrations and UCCR were increased in 86/196 (43.9%), 9/201 (4.5%) and 18/117 cats (15.3%), respectively. Prevalence did not differ between countries.

Conclusions

Hyperthyroidism is rare, whereas increased fPLI concentration, possibly reflecting pancreatitis, is common in diabetic cats. The high UCCR may reflect activation of the hypothalamus–pituitary–adrenal axis, which also occurs in diabetic humans. The percentage of cats with increased IGF-1 was high but lower than reported in recent studies.