Genome-wide based model predicting recovery from portosystemic shunting after liver shunt attenuation in dogs

Diagnosis and treatment of a congenital portosystemic shunt in a ferret (Mustela putorius furo)

A 3-year-old female neutered ferret presented with progressive weight loss was diagnosed with portosystemic shunting based on increased fasting bile acids, rectal ammonia tolerance testing and advanced imaging. Ammonia reference values were determined in 16 healthy ferrets. A congenital extrahepatic spleno-caval shunt was visualised with ultrasonography and CT angiography of the abdomen. Complete surgical shunt closure by suture ligation was performed, without clinical improvement after surgery. Euthanasia was elected 4 months postoperatively because the clinical condition deteriorated. This is a case report of advanced diagnostics and surgical treatment of a congenital extrahepatic portosystemic shunt in a ferret, demonstrating rectal ammonia tolerance testing and imaging as feasible techniques for the diagnosis.

Prediction of outcome after ligation or thin film banding of extrahepatic shunts, based on plasma albumin concentration and hematologic expression of 8 target genes in 85 dogs

BACKGROUND

In dogs with a congenital extrahepatic portosystemic shunt (EHPSS), outcome after surgical attenuation is difficult to predict.

OBJECTIVES

Develop a minimally invasive test to predict outcome after surgical EHPSS attenuation and establish risk factors for postattenuation seizures (PAS).

ANIMALS

Eighty-five client-owned dogs referred for surgical attenuation of a single EHPSS.

METHODS

mRNA expression of 8 genes was measured in preoperatively collected venous blood samples. Outcome was determined at a median of 92 days (range, 26-208) postoperatively by evaluating clinical performance, blood test results and abdominal ultrasonography. Multivariable logistic regression was used to construct models predicting clinical and complete recovery. The associations between putative predictors and PAS were studied using univariable analyses.

RESULTS

Five of 85 dogs developed PAS. Risk factors were age, white blood cell (WBC) count and expression of hepatocyte growth factor activator and LysM and putative peptidoglycan-binding domain-containing protein 2. Clinical recovery was observed in 72 of 85 dogs and complete recovery in 51 of 80 dogs (median follow-up, 92 days). The model predicting clinical recovery included albumin, WBC count, and methionine adenosyltransferase 2 alpha (MAT2α) expression, whereas the model predicting complete recovery included albumin, and connective tissue growth factor precursor and MAT2α expression. The areas under the receiver operating characteristic curves were 0.886 (95% confidence interval [CI]: 0.783, 0.990) and 0.794 (95% CI: 0.686, 0.902), respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

Two models were constructed for predicting outcome after EHPSS attenuation using venous blood samples. The model predicting clinical recovery showed the best diagnostic properties. Clinical application requires further validation.

Shear wave elastography measurements in dogs treated surgically for congenital extrahepatic portosystemic shunts

Assessing the postoperative surgical success of congenital extrahepatic portosystemic shunt (EHPSS) attenuation can be challenging and involve invasive imaging methods. Elastography is an ultrasound technique that allows qualitative and quantitative estimation of tissue stiffness and has extensively been used in people with liver disease. In recent years, increased interest in this technique has developed in veterinary medicine due to its non-invasive nature, availability, and low cost. The objective of this study was to compare liver stiffness values between dogs with closed EHPSS and those with multiple acquired portosystemic shunts (MAPSS) after gradual surgical attenuation and to assess whether shear wave elastography could be used to determine EHPSS closure. As a secondary objective, measurements obtained from both intercostal and subxiphoidal views were compared. Mean values for the average, median, and maximum two-dimensional shear wave velocities (2D SWV) for the closed EHPSS were 2.88 +/−0.11 m/s; 2.83 +/−0.11 m/s; and 3.75 +/−0.16 m/s, respectively. In the MAPSS dogs, mean values for the average, median, and maximum 2D SWV were 2.77 +/– 0.17 m/s; 2.71 +/– 0.17 m/s; and 3.66 +/−0.24 m/s, respectively. No significant differences in 2D SWV were present between dogs with closed EHPSS and those with MAPSS (P = 0.33; P = 0.33; P = 0.42, respectively). When assessing potential differences between intercostal and subxiphoidal 2D SWV measurements, no effect was observed for the average and median 2D SWV (P = 0.06; P = 0.07, respectively). Yet, a significant difference was identified for the maximum 2D SWV between intercostal 4.00 +/−0.20 m/s and subxiphoidal 3.41 +/−0.17 m/s measurements (P = 0.02). The relevance of this finding is uncertain as many other studies about liver elastography only report mean and not maximum values.

Intermittent fasting induces chronic changes in the hepatic gene expression of Red Jungle Fowl (Gallus gallus)

Background

Intermittent fasting (IF), the implementation of fasting periods of at least 12 consecutive hours on a daily to weekly basis, has received a lot of attention in recent years for imparting the life-prolonging and health-promoting effects of caloric restriction with no or only moderate actual restriction of caloric intake. IF is also widely practiced in the rearing of broiler breeders, the parent stock of meat-type chickens, who require strict feed restriction regimens to prevent the serious health problems associated with their intense appetites. Although intermittent fasting has been extensively used in this context to reduce feed competition and its resulting stress, the potential of IF in chickens as an alternative and complementary model to rodents has received less investigation. In both mammals and birds, the liver is a key component of the metabolic response to IF, responding to variations in energy balance. Here we use a microarray analysis to examine the liver transcriptomics of wild-type Red Jungle Fowl chickens fed either ad libitum, chronically restricted to around 70% of ad libitum daily or intermittently fasted (IF) on a 2:1 (2 days fed, 1 day fasted) schedule without actual caloric restriction. As red junglefowl are ancestral to domestic chicken breeds, these data serve as a baseline to which existing and future transcriptomic results from farmed birds such as broiler breeders can be compared.

Results

We find large effects of feeding regimen on liver transcriptomics, with most of the affected genes relating to energy metabolism. A cluster analysis shows that IF is associated with large and reciprocal changes in genes related to lipid and carbohydrate metabolism, but also chronic changes in genes related to amino acid metabolism (generally down-regulated) and cell cycle progression (generally up-regulated). The overall transcription pattern appears to be one of promoting high proliferative plasticity in response to fluctuations in available energy substrates. A small number of inflammation-related genes also show chronically changed expression profiles, as does one circadian rhythm gene.

Conclusions

The increase in proliferative potential suggested by the gene expression changes reported here indicates that birds and mammals respond similarly to intermittent fasting practices. Our findings therefore suggest that the health benefits of periodic caloric restriction are ubiquitous and not restricted to mammals alone. Whether a common fundamental mechanism, for example involving leptin, underpins these benefits remains to be elucidated.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08533-5.

Protein C and comparative biochemical changes in dogs treated with percutaneous transvenous coil embolization of congenital intrahepatic portosystemic shunts

OBJECTIVE

To evaluate protein C (PC) activity after intrahepatic portosystemic shunt (IHPSS) percutaneous transvenous coil embolization (PTCE) in dogs; to identify if PC is associated with clinical status after intervention, and to compare PC with standard biochemical values.

STUDY DESIGN

Retrospective case series.

ANIMALS

Forty-seven client-owned dogs with IHPSS undergoing PTCE.

METHODS

Records were reviewed for preoperative and postoperative PC, hematocrit (HCT), mean corpuscular volume (MCV), albumin (ALB), and blood urea nitrogen (BUN). Ultimate clinical status was classified as excellent, fair, or poor, based on ongoing medical management and the presence of clinical signs. Intrahepatic portosystemic shunt was considered to be completely or incompletely occluded intraoperatively based on angiography.

RESULTS

Postoperative PC activity increased in 37/47 (78.7%) dogs with a mean increase of 38.7% ± 2.1%. Ultimate postoperative clinical status was excellent in 16/43 (37.2%), fair in 19/43 (44.2%), and poor in 8/43 dogs (18.6%). No association was detected between preoperative PC (46.8% ± 1.8%) and ultimate clinical status but mean postoperative PC (75.7% ± 1.4%), HCT, MCV, ALB, and BUN were higher in dogs with excellent clinical status. Postoperative PC activity was higher when shunts were completely occluded (96.3% ± 10.9%), which was a finding associated with excellent status.

CONCLUSION

Postoperative, but not preoperative, PC activity was higher in dogs with better ultimate clinical status. Similar trends were noted in standard hematological and biochemical values. Complete occlusion of shunts was associated with a higher postoperative PC and superior ultimate clinical status.

CLINICAL SIGNIFICANCE

Postoperative PC may provide valuable information about the success of PTCE for IHPSS as it relates to the ultimate status and the need for additional procedures.

Postattenuation neurologic signs after surgical attenuation of congenital portosystemic shunts in dogs: A review

The development of postattenuation neurologic signs (PANS) is a poorly understood and potentially devastating complication after surgical attenuation of congenital portosystemic shunts in dogs. Postattenuation neurologic signs include seizures but also more subtle neurologic signs such as depression, behavioral changes, tremors, and twitching. They most commonly occur within 7 days postoperatively and are typically unrelated to hyperammonemia, hypoglycemia, or electrolyte disturbances. This narrative review summarizes the findings of 50 publications from 1988-2020 that report occurrence of PANS. While most published reports included only dogs affected by postattenuation seizures (PAS), others included dogs with any form of PANS. Overall, PANS (including PAS) affected 1.6%-27.3% of dogs, whereas incidence of PAS ranged from 0%-18.2%. The etiology of PANS remains unknown; however, several theories have been proposed. Risk factors include preoperative hepatic encephalopathy, increasing age, and possibly certain breeds and extrahepatic shunt morphology. There is increasing evidence that prophylactic antiepileptic drugs do not prevent PANS. Treatment is centered around controlling neurologic signs with antiepileptic drugs and providing supportive intensive care. The 30-day survival rate in studies that included a minimum of four dogs affected by PANS was 0%-100% (median, 50.0%) and 0%-75.0% (median, 37.5%) for those with PAS. Mortality associated with PANS was typically related to occurrence of generalized seizure activity. Prognostic factors positively associated with short-term survival included having a history of preoperative seizures and development of focal seizures only. If affected dogs survived to discharge, survival for several years was possible, and the majority of neurologic signs manifested as part of the phenomenon of PANS appeared to resolve.

Genome-wide based model predicting recovery from portosystemic shunting after liver shunt attenuation in dogs

Background

In dogs with congenital portosystemic shunt (CPSS), recovery after surgical CPSS attenuation is difficult to predict.

Objectives

Our aim was to build a model with plasma albumin concentration and mRNA expression levels of hepatic gene products as predictors of recovery from portosystemic shunting after surgery.

Animals

Seventy‐three client‐owned dogs referred for surgical attenuation of CPSS.

Methods

A prediction model was constructed using 2 case‐control studies of recovered and nonrecovered dogs after surgical CPSS attenuation. In the 1st study, a dog‐specific gene expression microarray analysis was used to compare mRNA expression in intraoperatively collected liver tissue between 23 recovered and 23 nonrecovered dogs. In the 2nd study, preoperative plasma albumin concentration and the expression of microarray‐selected genes were confirmed by RT‐qPCR in intraoperatively collected liver samples of 31 recovered and 31 nonrecovered dogs, including 35 dogs from the 1st study.

Results

In the 1st study, 43 genes were differently expressed in recovered and nonrecovered dogs. The mean preoperative plasma albumin concentration in recovered dogs was higher compared to nonrecovered dogs (23 and 19 g/L, respectively; P = .004). The best fitting prediction model in the 2nd study included preoperative plasma albumin concentration and intraoperative DHDH, ERLEC1, and LYSMD2 gene expression levels.

Conclusion and Clinical Importance

A preclinical model was constructed using preoperative plasma albumin concentration and intraoperative hepatic mRNA expression of 3 genes that were unbiasedly selected from the genome to predict recovery from portosystemic shunting after shunt ligation. Further development is essential for clinical application.