Transcatheter arterial embolization in normal canine liver

Therapeutic response and prognostic factors of 14 dogs undergoing transcatheter arterial embolization for hepatocellular masses: A retrospective study

BACKGROUND

Information regarding the therapeutic effect and outcome of transcatheter arterial embolization (TAE) for hepatic masses is limited in veterinary medicine.

HYPOTHESIS/OBJECTIVES

To analyze the therapeutic response, outcome (overall survival), and their predictors in dogs that underwent TAE for primary hepatocellular masses. We hypothesized that larger pre-TAE tumors would be associated with worse outcomes.

ANIMALS

Fourteen client-owned dogs.

METHODS

Retrospective study. Medical records between 1 September 2016 and 30 April 2022 were reviewed to identify dogs treated with TAE for hepatic masses diagnosed as hepatocellular origin by cytological or histopathological examination. Computed tomography images were compared before and after TAE. The univariate Cox proportional hazards test was performed to assess the associations between variables and survival. Univariate linear regression analysis was performed to assess the associations between variables and the tumor reduction percentage: ([post-TAE volume - pre-TAE volume]/pre-TAE volume) × 100.

RESULTS

The median survival time was 419 days (95% confidence interval, 82-474). History of intra-abdominal hemorrhage (P = .03) and pre-TAE tumor volume/body weight (P = .009) were significantly associated with overall survival. The mean reduction percentage was -51% ± 40%. Pre-TAE tumor volume/body weight ratio (cm3 /kg; P = .02, correlation coefficient = 0.704) was significantly correlated with the volume reduction percentage.

CONCLUSIONS

History of intra-abdominal hemorrhage and large pre-TAE tumor volume/body weight ratio could be predictive factors for adverse outcomes after TAE. Pre-TAE tumor volume/body weight ratio could be a predictive factor for therapeutic effect.

One-step Photocatalytic Synthesis of Fe3O4@Polydiallyl Isophthalate Magnetic Microspheres for Magnetocaloric Tumor Ablation and Its Potential for Tracing on MRI and CT

Allyl monomers that were previously considered to be difficult to polymerize are applied, and Fe₃O₄@polydiallyl isophthalate (Fe₃O₄@PDAIP) magnetic were synthesized by one-step photopolymerization. The skeleton of the microspheres is made of diallyl isophthalate (DAIP). We obtained the microspheres using the photo-click technique in a soft template with Nano-Fe₃O₄ evenly disseminated in hydrophobic DAIP by cation-π and polar interaction. The obtained Fe₃O₄@PDAIP magnetic microspheres can achieve tumor cell necrosis temperatures (41-52 ℃) in an alternating magnetic field due to their inherent magnetic response. The results of in vitro CT and MR imaging indicate that the microspheres might be monitored accurately in vivo. Then the structural characteristics of the microspheres were confirmed by morphological analysis and physicochemical property analysis. Experiments in vitro and in vivo revealed that the microspheres had an anti-tumor effect and their biocompatibility satisfies the standards. The stability experiment proves that the microspheres have the potential for long-term effectiveness in vivo. It demonstrates the promise of Fe₃O₄@PDAIP magnetic microspheres in clinical applications.

Short-interval recanalization after gelfoam occlusion

Gelfoam® is a temporary embolization agent often used in trauma where permanent arterial occlusion is not desired. Gelfoam occlusions have been shown to resolve by 2 weeks, but shorter intervals have not been studied. We report a case of spontaneous arterial hemorrhage due to ruptured hepatic malignancy where treatment was Gelfoam slurry occlusion of the right hepatic artery. Repeat hemorrhage resulted in repeat CT and hepatic arteriography, which showed that recanalization of the occluded artery had occurred in less than 48 hours. Gelfoam arterial occlusion in some cases may last less than 2 weeks.

Hepatoprotective role of peroxisome proliferator-activated receptor-α in non-cancerous hepatic tissues following transcatheter arterial embolization

Transcatheter arterial embolization (TAE) is a widely used technique in treating hepatic carcinoma but may cause liver injury in some cases. This study investigated the hepatoprotective effect of the preprocessed peroxisome proliferator-activated receptor-α (PPAR-α) agonist-WY-14643 following TAE. A total of 60 rabbit liver cancer models were developed and divided into a combined treatment (WY-14643 and TAE), TAE, and control groups. After TAE, we examined the histopathological picture and liver functions. Further, the expression of antioxidant enzymes, tumor necrosis factor-α (TNF-α), nuclear factor of κ-light chain of enhancer-activated B cells (NF-κB), PPAR-α, and B-cell lymphoma-2 (Bcl-2) was analyzed. Liver function tests, pathology score, and apoptosis index significantly worsened in the TAE group but were normalized in the combined treatment group. In addition, ELISA results showed that antioxidant enzyme activity significantly increased, while the malondialdehyde content and level of inflammatory cytokines were significantly reduced in the combined treatment group. Furthermore, compared to the TAE group, the expressions of PPAR-α, antioxidant enzymes superoxide dismutase1 (SOD1) and SOD2, and Bcl-2 were significantly elevated, while NF-κB was significantly reduced in the combined treatment group. On the other hand, the expression of NF-κB in tumor tissues was significantly reduced by pretreatment with WY-14643. Therefore, PPAR-α can ameliorate liver injury by exerting its anti-oxidative, anti-inflammatory, and anti-apoptotic functions.

Effect of drug-eluting bead transarterial chemoembolization loaded with cisplatin on normal dogs

Transcatheter arterial embolization (TAE) and transcatheter arterial chemoembolization (TACE) are standard treatments for advanced hepatocellular carcinoma (HCC) and particularly for unresectable tumors or liver metastases in humans. However, reports on TACE used in veterinary medicine are few. This study aimed to evaluate the feasibility and safety of drug-eluting bead transarterial chemoembolization (DEB-TACE). We performed DEB-TACE in four clinically normal dogs and pharmacokinetically compared the results against hepatic arterial infusion (HAI) of cisplatin in two dogs. Drug-eluting beads (DEB) loaded with cisplatin were injected through a microcatheter for selective embolization of the left hepatic artery. After embolization, computed tomography (CT) images and histological examination findings were obtained during a 4-week observation period. Serum platinum concentrations were measured to evaluate cisplatin after each procedure. Biochemical analysis was performed during a 12-week observation period. Embolization was successful in all dogs, and there were no clinically apparent abnormalities. Embolization was confirmed up to 4 weeks after DEB-TACE in two of the four dogs and up to 1 week in the other two dogs using postoperative CT images. Cisplatin was not detected in peripheral veins in all dogs after DEB-TACE, but it was detected in trace amounts after HAI. DEB-TACE using cisplatin was safe and well tolerated by normal dogs. DEB-TACE may be useful in terms of determining systemic toxicity and drug concentration within tumors.

Effect of transcatheter arterial embolisation in normal canine liver using trisacryl gelatine microspheres (Embosphere)

The effect of selective transcatheter arterial embolisation (TAE) using trisacryl gelatine microspheres (TGMs) in the normal canine liver was investigated. Selective embolisation was achieved by injecting TGMs into the left hepatic artery through a microcatheter in four healthy dogs. After embolisation, computed tomography (CT), biochemical analysis and histological examination were performed during a 12-week observation period. Embolisation was successful in all four dogs. Postoperative CT revealed consistent embolisation of the artery within the experimental period in three dogs. Hepatic enzyme levels slightly increased after embolisation but tapered to normal ranges. Histological examinations revealed no abnormal changes. Thus, selective TAE with TGMs was well tolerated in normal dogs and may be applicable to canine hepatocellular carcinoma.

Evaluation of hepatic tumor portal perfusion using mesenteric angiography: A pilot study in 5 dogs

BACKGROUND

Mesenteric angiography is a sensitive method for visualizing portal perfusion in the dog.

OBJECTIVES

To evaluate hepatic portal perfusion in dogs with incompletely resectable hepatic tumors using mesenteric angiography.

ANIMALS

Five client-owned dogs with incompletely resectable hepatic tumors evaluated with mesenteric angiography.

METHODS

Retrospective case series. Electronic medical records at the Animal Medical Center were analyzed to identify dogs that underwent mesenteric portography to determine blood flow to nonresectable hepatic tumors and subsequently determine ideal routes for transarterial embolization, vascular stent placement, or both. The images obtained from mesenteric angiography were analyzed and compared to those obtained from computed tomography angiography.

RESULTS

Portography was accomplished using direct mesenteric venography in 3 dogs with hepatocellular carcinoma (HCC), cranial mesenteric arteriography in 1 dog with hepatic adenoma or well-differentiated HCC, and via splenic arteriovenous fistula in 1 dog with diffuse hepatic hemangiosarcoma metastases. Mean pixel densities in areas of hepatic tumor growth identified statistically significant decreases in portal blood flow (P = .02) compared to normal hepatic parenchyma.

CONCLUSIONS AND CLINICAL IMPORTANCE

Initial findings indicate that the blood supply to large and metastatic hepatic tumors in dogs may correlate with that in humans, such that the majority of the tumor blood supply arises from the hepatic artery and not the portal vein. Differences in blood supply between normal hepatic parenchyma and hepatic tumors might be exploited by developing selective tumor therapies such as arterial embolization or chemoembolization that largely spare normal liver tissue. Further investigation is warranted.