Feline Hepatic Lipidosis

Evaluation of enzymatically hydrolyzed poultry byproduct meal effects on fecal microbiota and pressure variables in elderly obese cats

Arterial hypertension is influenced by the intestinal microbiota and its metabolites, which play a crucial role in host health. Dietary peptides are multifunctional molecules with therapeutic potential for managing hypertension. This study aimed to evaluate the impact of incorporating enzymatically hydrolyzed poultry byproduct meal (EHPM-c) into extruded dry diets on the fecal microbiota and blood pressure parameters of elderly obese cats. Eighteen owners of neutered, clinically healthy male and female cats of various breeds were randomly assigned to two groups: control (30.8%, conventional poultry byproduct meal-CPM-c) and test (17.07%, CPM-c + 12.0% EHPM-c). Clinical values of systolic blood pressure, serum aldosterone concentrations, angiotensin-converting enzyme I activity, and fecal microbiota using 16S rRNA were measured. Data were processed using SAS software (PROC MIXED, PROC GLIMMIX, and PROC CORR; p < 0.05). Both groups exhibited high microbial alpha diversity, with no significant differences in beta diversity. Although the inclusion of 12.0% EHPM-c had no measurable effect on blood pressure, both diets promoted beneficial modulation of the fecal microbiota, improving intestinal health. These findings underscore the importance of diet in maintaining gut homeostasis in obese senior cats. While the inclusion of 12.0% EHPM-c did not significantly alter blood pressure parameters, the modulation of the fecal microbiota suggests a potential role in maintaining intestinal health. These results highlight the need for further studies to explore different inclusion levels and longer intervention periods.

Metabolomic profiling of serum alterations and biomarker discovery in feline hepatic liposis

Feline hepatic lipidosis (FHL) is a common liver dysfunction caused by metabolic disorders. The objective was to evaluate the metabolic alteration in the cats of FHL and to identify biomarkers that can serve as biomarker for FHL. Differential metabolites in the serum of spontaneous FHL cats (FS, n = 12) and healthy cats (CS group, n = 12) were analyzed using GC/MS metabolomics. Differential metabolites with diagnostic significance were identified through receiver operating characteristic (ROC) curves. The expression level of the differential metabolite 2-hydroxybutyric acid (2-HB) was detected in the serum of the FS and CS groups, and biomarker were established. The biomarker efficacy of 2-HB for FHL was verified using serum samples from cats with FHL caused by different etiologies (F, n = 10) and healthy cats (C, n = 50). There were 13 significantly different metabolites between the CS and FS groups (VIP > 1, P < 0.05) with the area under the ROC curve (AUC) greater than 0.70. The AUC for serum 2-HB was 0.90 (95% confidence interval 0.767-1.000, P < 0.001), with an optimal critical value of 564.8 ng/L. By randomly detecting serum 2-HB in groups F and C (the optimal cut-off value is 564.8 ng/L), the detection rate for FHL diagnosis was 100% and the false positive rate was 0%. In cats with FHL, metabolic changes occur in amino acids, nucleotide sugars, glycerophospholipids, phenylalanine, galactose, alpha-linolenic acid, and glycerides. A serum 2-HB level greater than 564.8 ng/L serves as a biomarker for FHL.

Successful management of splenic perforation during percutaneous endoscopic gastrostomy tube placement in a cat via laparoscopic partial splenectomy

Case summary

A 12-year-old spayed female domestic shorthair cat with a weight of 4.5 kg and a body condition score of 3/9 presented with anorexia and vomiting. Feline hepatic lipidosis was diagnosed based on blood tests and ultrasound examination. Naso-oesophageal tube feeding was initiated, but hypersalivation persisted despite supportive care. As a result of poor feeding tolerance, a percutaneous endoscopic gastrostomy (PEG) tube was placed for long-term enteral nutrition, with endoscopic confirmation of gastric placement. Two hours after the procedure, blood staining on the PEG tube bandage suggested bleeding at the insertion site. Abdominal ultrasonography and CT revealed splenic perforation. A laparoscopic partial splenectomy was performed successfully and the cat recovered without complications. Follow-up laboratory tests demonstrated a gradual improvement in haematological parameters, including haematocrit and total bilirubin. The cat remained clinically stable without further complications.

Relevance and novel information

This report details the first documented case of splenic perforation during PEG tube placement in a cat, successfully managed through laparoscopic partial splenectomy. Minimally invasive laparoscopy has demonstrated efficacy in addressing rare complications, including splenic perforation associated with PEG tube placement in cats.

Association of time to start of enteral nutrition and outcome in cats with hepatic lipidosis

BACKGROUND

Enteral nutrition (EN) is essential for management of hepatic lipidosis (HL) in cats.

OBJECTIVES

To determine if time to start of EN and other clinicopathologic variables are associated with outcome in cats with HL.

ANIMALS

Forty-eight cats with HL.

METHODS

Retrospective study. Information retrieved from medical records and client communications included clinicopathologic findings, time to start of EN, initial % of resting energy requirements provided, type of feeding tube, duration of hospitalization, and 3-month survival. Variables were compared between surviving and nonsurviving cats and between cats fed ≤12 hours and >12 hours after hospital admission. Multivariable statistical testing was performed to further investigate variables of interest.

RESULTS

Seventeen of 25 (68%) cats fed ≤12 hours and 13 of 23 (57%) of cats fed >12 hours after hospital admission survived (P = .55). Only increasing age (odds ratio [OR], 1.313; 95% confidence interval [CI], 1.032-1.671; P = .03) and the presence of ascites (OR, 6.415; 95% CI, 1.354-30.395; P = .02) were associated with death in multivariable analysis. Hospitalization duration (median, interquartile range [IQR]) was shorter in cats fed >12 hours (2.8 days; IQR, 2.1-3.8 days) as compared with cats fed ≤12 hours (4.8 days; IQR, 3.6-6.2 days) after hospital admission (P < .001).

CONCLUSIONS AND CLINICAL IMPORTANCE

An initial stabilization period before EN introduction does not decrease survival or increase duration of hospitalization in cats with HL.

Insights into the interplay between gut microbiota and lipid metabolism in the obesity management of canines and felines

Obesity is a prevalent chronic disease that has significant negative impacts on humans and our companion animals, including dogs and cats. Obesity occurs with multiple comorbidities, such as diabetes, hypertension, heart disease and osteoarthritis in dogs and cats. A direct link between lipid metabolism dysregulation and obesity-associated diseases has been implicated. However, the understanding of such pathophysiology in companion animals is limited. This review aims to address the role of lipid metabolism in various metabolic disorders associated with obesity, emphasizing the involvement of the gut microbiota. Furthermore, we also discuss the management of obesity, including approaches like nutritional interventions, thus providing novel insights into obesity prevention and treatment for canines and felines.

Species-specific histological characterizations of renal tubules and collecting ducts in the kidneys of cats and dogs

The histomorphological features of normal kidneys in cats and dogs have been revealed despite the high susceptibility of cats to tubulointerstitial damage. Herein, the histological characteristics of the two species were compared. Cytoplasmic lipid droplets (LDs) were abundant in the proximal convoluted tubules (PCTs) of cats aged 23-27 months but scarce in dogs aged 24-27 months. LDs were rarely observed in the distal tubules (DTs) and collecting ducts (CDs) of either species, as visualized by the expression of Tamm-Horsfall protein 1, calbindin-D28K, and aquaporin 2. The occupational area ratio of proximal tubules (PTs) in the renal cortex was higher, but that of DTs or CDs was significantly lower in adult cats than in dogs. Single PT epithelial cells were larger, but PCT, DT, and CD lumens were significantly narrower in adult cats than in dogs. Unlike adults, young cats at 6 months exhibited significantly abundant cytoplasmic LDs in proximal straight tubules, indicating lipid metabolism-related development. Histochemistry of the 21 lectins also revealed variations in glycosylation across different renal tubules and CDs in both species. Sodium-glucose cotransporter 2 was expressed only in PTs, excluding the proximal straight tubules with few LDs in adult cats or the PCTs of young cats and adult dogs. These findings are crucial for understanding species-specific characteristics of renal histomorphology and pathogenesis.

The Diagnostic Value of Serum Amyloid A and Other Laboratory and Clinical Variables in Cats with Increased Liver Enzyme Activity

Distinguishing inflammatory from non-inflammatory liver disease in cats may impact management. The study aim was to evaluate if certain diagnostic variables, including Serum Amyloid A (SAA), differ (1) between various clinical disease categories (Primary liver disease, Extrahepatic, Trauma and Inconclusive) and (2) between cytological findings of severe hepatic lipidosis and other cytological findings in cats with increased liver enzymes. Medical records from 5042 cats, where SAA had been measured, were reviewed, and 566 cats fulfilled inclusion criteria consisting of increased liver enzymes and available biochemical panel results. SAA was higher in cats diagnosed with trauma compared to other diseases (p = 0.008). Cytology results were available in 85 cats, and cats with severe lipidosis had lower serum SAA concentration (p < 0.0001) and were younger (p < 0.0002) compared to cats with other cytological findings. The study shows that SAA was higher in cats diagnosed with trauma compared to cats with other causes of increased liver enzymes and that SAA may be useful to distinguish cats with cytologic evidence of hepatic lipidosis from cats with other liver pathologies. Serum Amyloid A may be a valuable complement to liver cytology when investigating cats with increased liver enzymes.

Starvation-resistant cavefish reveal conserved mechanisms of starvation-induced hepatic lipotoxicity

Starvation causes the accumulation of lipid droplets in the liver, a somewhat counterintuitive phenomenon that is nevertheless conserved from flies to humans. Much like fatty liver resulting from overfeeding, hepatic lipid accumulation (steatosis) during undernourishment can lead to lipotoxicity and atrophy of the liver. Here, we found that although surface populations of Astyanax mexicanus undergo this evolutionarily conserved response to starvation, the starvation-resistant cavefish larvae of the same species do not display an accumulation of lipid droplets upon starvation. Moreover, cavefish are resistant to liver atrophy during starvation, providing a unique system to explore strategies for liver protection. Using comparative transcriptomics between zebrafish, surface fish, and cavefish, we identified the fatty acid transporter slc27a2a/fatp2 to be correlated with the development of fatty liver. Pharmacological inhibition of slc27a2a in zebrafish rescues steatosis and atrophy of the liver upon starvation. Furthermore, down-regulation of FATP2 in Drosophila larvae inhibits the development of starvation-induced steatosis, suggesting the evolutionarily conserved importance of the gene in regulating fatty liver upon nutrition deprivation. Overall, our study identifies a conserved, druggable target to protect the liver from atrophy during starvation.

Description of the fasted serum metabolomic signature of lean and obese cats at maintenance and of obese cats under energy restriction

This study aimed to investigate the serum metabolomic profile of obese and lean cats as well as obese cats before and after energy restriction for weight loss. Thirty cats, 16 obese (body condition score 8 to 9/9) and 14 lean (body condition score 4 to 5/9), were fed a veterinary weight loss food during a 4-week period of weight maintenance (L-MAINT and O-MAINT). The 16 obese cats were then energy restricted by a 60% energy intake reduction with the same food for a 10-week period (O-RESTRICT). Fasted serum metabolites were measured using nuclear magnetic resonance and direct infusion mass spectrometry after the maintenance period for L-MAINT and O-MAINT cats and after the energy restriction period for O-RESTRICT and compared between groups using a two-sided t-test. Obese cats lost 672 g ± 303 g over the 10-week restriction period, representing a weight loss rate of 0.94 ± 0.28% per week. Glycine, l-alanine, l-histidine, l-glutamine, 2-hydroxybutyrate, isobutryric acid, citric acid, creatine, and methanol were greater in O-RESTRICT compared to O-MAINT. There was a greater concentration of long-chain acylcarnitines in O-RESTRICT compared to both O-MAINT and L-MAINT, and greater total amino acids compared to O-MAINT. Glycerol and 3-hydroxybutyric acid were greater in O-MAINT compared to L-MAINT, as were several lysophosphatidylcholines. Thus, energy restriction resulted in increased dispensable amino acids in feline serum which could indicate alterations in amino acid partitioning. An increase in lipolysis was not evident, though greater circulating acylcarnitines were observed, suggesting that fatty acid oxidation rates may have been greater under calorie restriction. More research is needed to elucidate energy metabolism and substrate utilization, specifically fatty acid oxidation and methyl status, during energy restriction in strict carnivorous cats to optimize weight loss.

Starvation resistant cavefish reveal conserved mechanisms of starvation-induced hepatic lipotoxicity

Starvation causes the accumulation of lipid droplets in the liver, a somewhat counterintuitive phenomenon that is nevertheless conserved from flies to humans. Much like fatty liver resulting from overfeeding, hepatic lipid accumulation (steatosis) during undernourishment can lead to lipotoxicity and atrophy of the liver. Here, we found that while surface populations of Astyanax mexicanus undergo this evolutionarily conserved response to starvation, the starvation-resistant cavefish larvae of the same species do not display an accumulation of lipid droplets upon starvation. Moreover, cavefish are resistant to liver atrophy during starvation, providing a unique system to explore strategies for liver protection. Using comparative transcriptomics between zebrafish, surface fish, and cavefish, we identified the fatty acid transporter slc27a2a/fatp2 to be correlated with the development of fatty liver. Pharmacological inhibition of slc27a2a in zebrafish rescues steatosis and atrophy of the liver upon starvation. Further, down-regulation of FATP2 in drosophila larvae inhibits the development of starvation-induced steatosis, suggesting the evolutionary conserved importance of the gene in regulating fatty liver upon nutrition deprivation. Overall, our study identifies a conserved, druggable target to protect the liver from atrophy during starvation.

Programming of metabolic and autoimmune diseases in canine and feline: linkage to the gut microbiome

Metabolic and autoimmune disorders have long represented challenging health problems because of their growing prevalence in companion animals. The gut microbiome, made up of trillions of microorganisms, is implicated in multiple physiological and pathological processes. Similar to human beings, the complicated microbiome harbored in the gut of canines and felines emerges as a key factor determining a wide range of normal and disease conditions. Evidence accumulated from recent findings on canine and feline research uncovered that the gut microbiome is actively involved in host metabolism and immunity. Notably, the composition, abundance, activity, and metabolites of the gut microbiome are all elements that shape clinical outcomes concerning metabolism and immune function. This review highlights the implications of the gut microbiome for metabolic disorders (obesity, diabetes, and hepatic lipidosis) and autoimmune diseases (inflammatory bowel disease, osteoarthritis, asthma, and myasthenia gravis) in canine and feline animals, providing novel strategies and therapeutic targets for the prevention and treatment of pet diseases.

Association of plasma metabolites and diagnostic imaging findings with hepatic lipidosis in bearded dragons (Pogona vitticeps) and effects of gemfibrozil therapy

OBJECTIVES

To evaluate the association between plasma metabolites, biochemical analytes, diagnostic imaging findings, and the histologic diagnosis of hepatic lipidosis in bearded dragons. To assess the effects of gemfibrozil therapy on hepatic lipid accumulation and associated diagnostic tests.

ANIMALS

Fourteen bearded dragons (Pogona vitticeps) with varying severity of hepatic lipid accumulation (with and without hepatic lipidosis) were included.

PROCEDURES

Animals underwent coelomic ultrasound, computed tomography (CT) scans, and coelioscopic hepatic biopsies. Clinical pathology tests included lipidologic tests, hepatic biomarkers, and mass spectrometry-based metabolomics. Animals were medicated with gemfibrozil 6mg/kg orally once a day for 2 months in a randomized blinded clinical trial prior to repeating previous diagnostic testing.

RESULTS

Hounsfield units on CT were negatively associated with increased hepatic vacuolation, while ultrasound and gross evaluation of the liver were not reliable. Beta-hydroxybutyric-acid (BHBA) concentrations were significantly associated with hepatic lipidosis. Metabolomics and lipidomics data found BHBA and succinic acid to be potential biomarkers for diagnosing hepatic lipidosis in bearded dragons. Succinic acid concentrations were significantly lower in the gemfibrozil treatment group. There was a tendency for improvement in the biomarkers and reduced hepatic fat in bearded dragons with hepatic lipidosis when treated with gemfibrozil, though the improvement was not statistically significant.

CONCLUSIONS

These findings provide information on the antemortem assessment of hepatic lipidosis in bearded dragons and paves the way for further research in diagnosis and treatment of this disease.

Environmental risk factors in puppies and kittens for developing chronic disorders in adulthood: A call for research on developmental programming

Many dogs and cats are affected by chronic diseases that significantly impact their health and welfare and relationships with humans. Some of these diseases can be challenging to treat, and a better understanding of early-life risk factors for diseases occurring in adulthood is key to improving preventive veterinary care and husbandry practices. This article reviews early-life risk factors for obesity and chronic enteropathy, and for chronic behavioral problems, which can also be intractable with life-changing consequences. Aspects of early life in puppies and kittens that can impact the risk of adult disorders include maternal nutrition, establishment of the gut microbiome, maternal behavior, weaning, nutrition during growth, growth rate, socialization with conspecifics and humans, rehoming and neutering. Despite evidence in some species that the disorders reviewed here reflect the developmental origins of health and disease (DOHaD), developmental programming has rarely been studied in dogs and cats. Priorities and strategies to increase knowledge of early-life risk factors and DOHaD in dogs and cats are discussed. Critical windows of development are proposed: preconception, gestation, the suckling period, early growth pre-neutering or pre-puberty, and growth post-neutering or post-puberty to adult size, the durations of which depend upon species and breed. Challenges to DOHaD research in these species include a large number of breeds with wide genetic and phenotypic variability, and the existence of many mixed-breed individuals. Moreover, difficulties in conducting prospective lifelong cohort studies are exacerbated by discontinuity in pet husbandry between breeders and subsequent owners, and by the dispersed nature of pet ownership.

Use of feeding tubes in 112 cats in an internal medicine referral service (2015-2020)

OBJECTIVES

The aims of this study were to describe diseases, complications and outcomes associated with the use of feeding tubes in a population of sick cats with appetite disturbance managed at an internal medicine referral service.

METHODS

Clinicopathological data from cats receiving nasoenteral (NE) or oesophagostomy (O) tubes were studied. Cats were categorised according to their underlying disease and divided into subgroups (NE or O tube). The following factors associated with survival were analysed: disease category, type of tube and return to appetite.

RESULTS

Included in the study were 112 cats, representing 118 cases. Of the 118 cases, 98 (83%) and 20 (17%) received NE or O tubes, respectively. The most common underlying conditions were digestive (13.5%), hepatobiliary (11%) and upper urinary tract (11%) disorders. Hepatobiliary (50%) and upper respiratory tract (30%) conditions were predominant in the O tube group. Digestive (15%) and upper urinary tract (12%) diseases were more common in the NE tube group. Complications following tube placement occurred in 22/118 cases (18.6%). The global survival rate was 73% and did not differ between NE (71.4%) and O tube (80%) groups (P = 1.00) or disease categories (P = 0.61). Return of appetite before feeding tube removal occurred in 56 cases (47%), within a median of 3 days (range 1-30) and was not associated with mirtazapine administration (P = 1.00). Appetite returned earlier for cats with NE tubes (3 days, range 1-17) than for those with O tubes (33 days, range 5-60; P <0.05). Voluntary food intake was positively associated with survival (odds ratio 15.17). After discharge and feeding tube retrieval, return of appetite was observed in 67% of cases.

CONCLUSIONS AND RELEVANCE

Feeding tubes were predominantly placed for the management of appetite disturbance in cats with digestive, hepatobiliary and upper urinary tract diseases. While complications were frequent, they were mostly mild, easily managed and did not preclude feeding tube use. Return to appetite occurred in a large proportion of cats during or after assisted enteral feeding and was associated with survival.

Prevalence, risk factors, and disease associations of overweight and obesity in cats that visited the Veterinary Medical Teaching Hospital at the University of California, Davis from January 2006 to December 2015

Overweight and obesity are commonly diagnosed in domestic cats, and undermine cats' quality of life directly or indirectly via various disease processes known to be associated with overweight and obesity. Epidemiological studies have reported varied overall prevalence among different feline populations, and commonly identified risk factors such as neutering. However, disease associations were not consistently reported. The status of feline overweight and obesity in a referral veterinary teaching hospital in the United States remains undefined as well. The present study used descriptive statistics and logistic regression models to analyze feline medical records obtained at the Veterinary Medical Teaching Hospital at the University of California, Davis from January 2006 to December 2015 and to characterize the prevalence of overweight and obesity, risk factors, and disease associations. In 9,062 feline records analyzed, the overall prevalence of overweight (17.2%; n = 1,560) and obesity (23.8%; n = 2,160) was 41.0%. Neutered, male, and crossbred cats that were in age groups between 3.0 and 14.9 years old and presented with disease processes in orthopedic, dentistry, and urinary categories were positively associated with overweight and obesity. Overweight and obesity are prevalent problems, which can benefit from continual veterinary education emphasizing its importance. Structured disease surveillance plans monitoring these associated factors also help guide further research and ideally can contribute to development of better prevention strategies for overweight and obesity.

Serum Lipid, Amino Acid and Acylcarnitine Profiles of Obese Cats Supplemented with Dietary Choline and Fed to Maintenance Energy Requirements

Obesity is a health concern for domestic cats. Obesity and severe energy restriction predispose cats to feline hepatic lipidosis. As choline is linked to lipid metabolism, we hypothesized that dietary choline supplementation would assist in reducing hepatic fat through increased lipoprotein transport and fatty acid oxidation. Twelve obese cats (body condition score [BCS] ≥ 8/9) were split into two groups. Cats were fed a control (n = 6; 4587 mg choline/kg dry matter [DM]) or a high choline diet (n = 6; 18,957 mg choline/kg DM) for 5 weeks, for adult maintenance. On days 0 and 35, fasted blood was collected, and the body composition was assessed. Serum lipoprotein and biochemistry profiles, plasma amino acids and plasma acylcarnitines were analyzed. The body weight, BCS and body composition were unaffected (p > 0.05). Choline increased the serum cholesterol, triacylglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol and plasma methionine (p < 0.05) and decreased the serum blood urea nitrogen and alkaline phosphatase (p < 0.05). Choline also reduced the plasma acylcarnitine to free carnitine ratio (p = 0.006). Choline may assist in eliminating hepatic fat through increased fat mobilization and enhanced methionine recycling.

Safety, Tolerability, and Proof-Of-Concept Study of OKV-119, a Novel Exenatide Long-Term Drug Delivery System, in Healthy Cats

Background: Glucagon-like peptide-1 (GLP-1) is an incretin hormone that plays an important role in glucose homeostasis and food intake. In people, GLP-1 receptor agonists (GLP-1RAs) are commonly used for the treatment of type 2 diabetes mellitus (DM) and obesity; however, non-adherence to injectable medications is common. OKV-119 is an investigational drug delivery system intended for subdermal implantation and delivery of the GLP-1RA exenatide for up to 6 months.

Hypothesis/Objectives: Develop protocols for the subcutaneous (SC) insertion and removal of OKV-119 and to evaluate its tolerability, in vivo drug-releasing characteristics, and weight-loss effects in cats.

Animals: Two cadaveric and 19 purpose-bred cats.

Methods: In cadavers, OKV-119 insertion protocol and imaging were performed at three SC locations. The safety and tolerability of OKV-119 implants were assessed in a small (n = 4 cats) 62-day study. Weekly plasma exenatide concentrations and body weight were measured in a 42-day proof-of-concept study designed to evaluate OKV-119 prototypes implanted in cats (n = 15).

Results: In anesthetized cats, the duration of insertion and removal procedures was 1–2 min. OKV-119 was easily identified on radiographs, and well-tolerated without any apparent implant site reactions. Following implantation, exanatide plasma concentrations were observed for up to 35 days. Plasma exenatide concentrations were correlated to weight loss.

Conclusion and clinical importance: Our findings suggest that OKV-119 could be easily inserted and removed during a routine clinic visit and can be used to safely and effectively deliver exenatide. Future studies of OKV-119, configured to release exenatide for a longer extended months-long duration, are warranted to determine whether the combination of metabolic improvements and beneficial weight-loss, coupled with minimal impact on pet-owner's lifestyle, lead to improved outcomes for obese cats and feline DM patients.

Evidence-Based Medicine: Ultrasound-Guided Percutaneous Cholecystocentesis in the Cat

Cholangitis is a common cause of hepatobiliary disease in the cat. Feline cholangitis is characterized as neutrophilic (acute or chronic), lymphocytic, or caused by liver flukes. The neutrophilic form is caused by bacterial infection of the biliary system, and identification of the specific bacterial agent guides treatment. Bile is the sample of choice for cytology and bacterial culture in these cases, and percutaneous ultrasound-guided cholecystocentesis is used to obtain that sample. This review covers the literature that provides evidence for safety and usefulness of percutaneous ultrasound-guided cholecystocentesis as part of the diagnostic work-up of cats suspected of having hepatobiliary disease.

Gene expressions of de novo hepatic lipogenesis in feline hepatic lipidosis

OBJECTIVES

The aim of this study was to evaluate if de novo hepatic lipid synthesis contributes to fatty acid overload in the liver of cats with feline hepatic lipidosis (FHL).

METHODS

Lipogenic gene expression of peroxisome proliferator-activated receptor-alpha (PPAR-α), peroxisome proliferator-activated receptor-gamma (PPAR-γ), fatty acid synthase (FASN) and sterol regulatory element-binding factor (SREBF1) were evaluated using quantitative RT-PCR in liver tissue of six cats with FHL and compared with the liver tissue of eight healthy cats.

RESULTS

In liver tissue, PPAR-α, PPAR-γ and FASN mRNA expression levels were not significantly different (P >0.12, P >0.89 and P >0.5, respectively) in the FHL group compared with the control group. SREBF1 gene expression was downregulated around 10-fold in the FHL group vs the control group (P = 0.039).

CONCLUSIONS AND RELEVANCE

The downregulation of SREBF1 in the liver tissue of cats with FHL does not support the hypothesis that de novo lipogenesis in the liver is an important pathway of fatty acid accumulation in FHL.

Identification of potential drugs for treatment of hepatic lipidosis in cats using an in vitro feline liver organoid system

Background

Hepatic lipidosis is increasing in incidence in the Western world, with cats being particularly sensitive. When cats stop eating and start utilizing their fat reserves, free fatty acids (FFAs) increase in blood, causing an accumulation of triacylglycerol (TAG) in the liver.

Objective

Identifying potential new drugs that can be used to treat hepatic lipidosis in cats using a feline hepatic organoid system.

Animals

Liver organoids obtained from 6 cats.

Methods

Eight different drugs were tested, and the 2 most promising were further studied using a quantitative TAG assay, lipid droplet staining, and qPCR.

Results

Both T863 (a diacylglycerol O‐acyltransferase 1 [DGAT1] inhibitor) and 5‐aminoimidazole‐4‐carboxamide 1‐β‐D‐ribofuranoside (AICAR; an adenosine monophosphate kinase activator) decreased TAG accumulation by 55% (P < .0001) and 46% (P = .0003), respectively. Gene expression of perilipin 2 (PLIN2) increased upon the addition of FFAs to the medium and decreased upon treatment with AICAR but not significantly after treatment with T863.

Conclusions and Clinical Importance

Two potential drugs useful in the treatment of hepatic lipidosis in cats were identified. The drug T863 inhibits DGAT1, indicating that DGAT1 is the primary enzyme responsible for TAG synthesis from external fatty acids in cat organoids. The drug AICAR may act as a lipid‐lowering compound via decreasing PLIN2 mRNA. Liver organoids can be used as an in vitro tool for drug testing in a species‐specific system and provide the basis for further clinical testing of drugs to treat steatosis.

Outcomes of eight cats with oral neoplasia treated with radical mandibulectomy

OBJECTIVE

To report outcomes after radical mandibulectomy in cats.

STUDY DESIGN

Multi-institutional retrospective study.

ANIMALS

Eight cats were included.

METHODS

Medical records were searched for cats with confirmed oral neoplasia treated with radical mandibulectomy. Data collected included demographics, surgical procedure, histopathological diagnosis, postoperative management, and outcomes.

RESULTS

Ages ranged from 8 to 17 years. All cats had 75% to 90% of the mandible removed and feeding tubes placed. Seven cats had squamous cell carcinoma, and one cat had a giant cell tumor. Six cats ate on their own postoperatively. Three cats had local recurrence and tumor-related died at 136 and 291 days. Six cats had no recurrence, with survival times of 156, 465, 608, and 1023 days, and two cats were still alive at 316 and 461 days after surgery. The three long-term survivors died of causes unrelated to oral neoplasia. One cat died at 156 days due to aspiration of food material. The overall estimated mean survival time was 712 days.

CONCLUSION

After radical mandibulectomy, independent food intake was achieved in 6 of eight cats, and four cats lived longer than one year.

CLINICAL SIGNIFICANCE

Radical mandibulectomy should be considered for the treatment of extensive oral neoplasia in cats. Successful long-term outcomes are possible with aggressive supportive care perioperatively.

Evaluation of the radiographic liver length/11th thoracic vertebral length ratio as a method for quantifying liver size in cats

Abdominal radiography is a standard diagnostic test for cats with suspected liver disease, however, absolute measurements of radiographic liver size can be affected by other factors such as positioning, radiographic technique, and obesity. This prospective and retrospective, analytical, cross-sectional study evaluated the liver length/11th thoracic vertebral length (LL/T11) ratio as a method for minimizing these outside effects. In a prospectively recruited sample of 25 clinically healthy cats, measurements of radiographic LL/T11 ratio were compared with CT measurements of liver volume. Effects of radiographic technical factors (body posture, recumbency state, and beam center to LL/T11 ratio) and observer were also tested. In a retrospectively recruited sample of 324 cats with no evidence of liver disease, radiographic measurements of the LL/T11 ratio were performed using right lateral radiographs and compared among signalment groups (age, sex, body weight, and body condition score). There was a strong significant correlation between the LL/T11 ratio and CT liver volume (P < .001), and this ratio was not affected by radiographic technical factors. The reference value of the LL/T11 ratio was 4.22 ± 0.54 and the LL/T11 ratio did not differ among signalment groups. Findings supported the use of the LL/T11 ratio as a novel quantitative index of radiographic liver size in cats. Future studies in clinically affected cats are needed to further validate this method.

Altered lipoprotein profiles in cats with hepatic lipidosis

OBJECTIVES

The aim of this study was to assess serum lipoprotein profiles using rapid single-spin continuous lipoprotein density profiling (CLPDP) in healthy control cats and cats with hepatic lipidosis (HL).

METHODS

Analysis of serum lipoprotein profiles using the CLPDP was performed in 23 cats with HL and 20 healthy control cats. The area under the curve for each lipoprotein fraction, triglyceride (TG)-rich lipoproteins (TRLs), low-density lipoproteins (LDLs) and high-density lipoproteins (HDLs), was calculated. Serum cholesterol and TG concentrations were measured using a clinical chemistry analyzer.

RESULTS

Serum cholesterol and TG concentrations were not significantly different between healthy control cats and cats with HL ( P = 0.5075 and P = 0.2541, respectively). LDL content was significantly higher in cats with HL than in healthy control cats ( P = 0.0001), while HDL content was significantly lower in cats with HL than in healthy control cats ( P = 0.0032). TRL content was not significantly different between the two groups ( P = 0.0699). The specific fraction (1.037-1.043 g/ml) within nominal LDL in serum distinguished healthy control cats from cats with HL with a sensitivity of 87% and a specificity of 90%.

CONCLUSIONS AND RELEVANCE

Serum lipoprotein profiles were altered in cats with HL, even though serum cholesterol and TG concentrations were not significantly different compared with healthy control cats. The CLPDP might be a useful tool for assessing lipid metabolism in cats with HL.

Immunohistochemical characterisation of the hepatic stem cell niche in feline hepatic lipidosis: a preliminary morphological study

OBJECTIVES

The aim of this study was to describe the cellular and stromal components of the hepatic progenitor cell niche in feline hepatic lipidosis (FHL).

METHODS

Immunohistochemical staining for the progenitor/bile duct marker (K19), activated Kupffer cells (MAC387), myofibroblasts (alpha-smooth muscle actin [α-SMA]) and the extracellular matrix component laminin were used on seven liver biopsies of cats with FHL and three healthy cats. Double immunofluorescence stainings were performed to investigate co-localisation of different cell types in the hepatic progenitor cell (HPC) niche.

RESULTS

HPCs, Kupffer cells, myofibroblasts and laminin deposition were observed in the liver samples of FHL, although with variability in the expression and positivity of the different immunostainings between different samples. When compared with the unaffected cats where K19 positivity and minimal α-SMA and laminin positivity were seen mainly in the portal area, in the majority of FHL samples K19 and α-SMA-positive cells and laminin positivity were seen also in the periportal and parenchymatous area. MAC387-positive cells were present throughout the parenchyma.

CONCLUSIONS AND RELEVANCE

This is a preliminary morphological study to describe the activation and co-localisation of components of the HPC niche in FHL. Although the HPC niche in FHL resembles that described in hepatopathies in dogs and in feline lymphocytic cholangitis, the expression of K19, α-SMA, MAC387 and lamin is more variable in FHL, and a common pattern of activation could not be established. Nevertheless, when HPCs were activated, a spatial association between HPCs and their niche could be demonstrated.

A double-blind, placebo-controlled, randomized study to evaluate the weight gain drug, mirtazapine transdermal ointment, in cats with unintended weight loss

Mirtazapine is classified as a weight gain drug in cats, and the purpose of this study was to evaluate its efficacy in cats experiencing unintended weight loss. This was a multi-center, double-blind, placebo-controlled, randomized clinical study in client-owned cats ≥1 year of age, weighing ≥2 kg, with a documented loss (≥5%) in body weight. Cats were treated once daily with either 2 mg/cat mirtazapine transdermal ointment (n = 83) or placebo (n = 94) (Per Protocol population) applied to the inner surface of the pinna for 14 ± 3 days. Physical examination, body weight, complete blood count, serum chemistry, and urinalysis were performed prior to treatment and on Day 14. Changes in body weight between the mirtazapine and placebo groups were evaluated from Day 1 to Day 14 and compared using a two-sample t test. The mean percent change in body weight was +3.9% (standard deviation ±5.4%) in the mirtazapine group and +0.4% (±3.3%) in the placebo group (p < 0.0001). The most common adverse event was mild erythema at the application site in 17.4% of placebo and 10.4% of mirtazapine-treated cats. Application of mirtazapine transdermal ointment was well tolerated both topically and systemically and resulted in significant weight gain in cats experiencing unintended weight loss associated with various underlying diseases.

Atopic dermatitis in cats and dogs: a difficult disease for animals and owners

The purpose of this review article is to give an overview of atopic dermatitis in companion animals and of recent developments including knowledge on immunological background, novel treatment options and difficulties in disease management. The prevalence of hypersensitivities seems to be increasing. The pathogenetic mechanisms are not fully understood, yet multiple gene abnormalities and altered immunological processes are involved. In dogs and cats, the diagnosis of atopic dermatitis is based on history, clinical examination and exclusion of other differential diagnoses. Intradermal testing or testing for serum allergen-specific Immunoglobulin E is only used to identify allergens for inclusion in the extract for allergen immunotherapy. Symptomatic therapy includes glucocorticoids, ciclosporin, essential fatty acids and antihistamines. A selective janus kinase 1 inhibitor and a caninized monoclonal interleukin-31 antibody are the newest options for symptomatic treatment, although longterm effects still need to be assessed. The chronic and often severe nature of the disease, the costly diagnostic workup, frequent clinical flares and lifelong treatment are challenging for owners, pets and veterinarians. Patience and excellent communication skills are needed to achieve a good owner compliance and satisfactory clinical outcome for the animal.

Independent modes of disease repair by AIM protein distinguished in AIM-felinized mice

Tissue macrophage-derived apoptosis inhibitor of macrophage (AIM, encoded by cd5l gene) is a circulating protein that has suppressive functions in a broad range of diseases including obesity, liver steatosis, hepatocellular carcinoma (HCC), and acute kidney injury (AKI). In healthy states, high levels of AIM circulate in the inactivated state by associating with the immunoglobulin M (IgM) pentamer in the blood, whereas during AKI, AIM dissociates from IgM and gains disease repair activity. Here, we assessed whether AIM activation via its release from IgM is required to ameliorate other diseases. To this end, we employed a mouse line in which mouse AIM was replaced with feline AIM (AIM-felinized mice). Because feline AIM rarely dissociates from IgM due to its extremely high binding affinity for IgM, these mice exhibited deficient AKI repair as in cats. When fed a high-fat diet (HFD), similar to AIM-deficient (AIM^−/−) mice, AIM-felinized mice exhibited enhanced triacylglycerol deposition in visceral adipocytes and hepatocytes, resulting in more prominent obesity and fatty liver than in wild-type mice. In contrast, the incidence of HCC after a 1-year HFD was remarkably lower in AIM-felinized mice than in AIM^−/− mice, suggesting that AIM produced by liver Kupffer macrophages might directly facilitate the elimination of HCC cells. Accordingly, the marked deposition of AIM accompanied by accumulation of Kupffer cells was obvious during HCC tumour development in AIM-felinized mice. Δsµ mice, which harbour almost no circulating AIM due to the lack of secreted IgM, showed a phenotype comparable with that of AIM-felinized mice in prevention of those diseases. Thus, blood AIM released from IgM contributes to suppression of obesity and fatty liver as in AKI, whereas macrophage-derived noncirculating AIM mainly prevents HCC development. Our study depicted two different modes of disease prevention/repair facilitated by AIM, which could be the basis for HCC therapy that works by increasing AIM expression in macrophages.

Hepatic lipidosis: Clinical review drawn from collective effort

Practical relevance: Hepatic lipidosis (HL) is the most common form of liver dysfunction in cats. If recognized early and treated appropriately, the prognosis is good; if not, the prognosis is grave. Clinical challenges: Distinguishing HL as idiopathic or secondary is critical since the presence of a concurrent disease affects the therapeutic plan and the prognosis.

AUDIENCE

Despite the unique and severe nature of a cat's response to anorexia and the complexity of the metabolic changes underlying this condition, the clinical acumen and technical ability to effectively diagnose and treat HL are readily available to all small animal practitioners. Patient group: Although many species develop a 'fatty liver', the cat is one of relatively few species that suffer from HL. The classic presentation is that of an overweight cat that stops eating for days to weeks, losing weight in the process. Equipment: Abdominal ultrasound is frequently employed in the diagnostic work-up of an anorectic cat; ultrasonographic findings often support a presumptive diagnosis, provide samples for cytology and, perhaps most importantly, help identify concurrent conditions that must be addressed for therapeutic success. All of the equipment necessary for essential nutritional intervention in an anorectic cat is readily available and easily affordable. Evidence base: The material for this review draws heavily on a relatively large number of original studies, excellent reviews by recognized experts, and informative communication with experienced clinicians, hence the term 'collective effort'.