Hilde de Rooster

Sepsis is a life-threatening condition in which a dysregulated host response to infection leads to organ dysfunction and metabolic and immune failure. We identify hepatocyte retinoid X receptor α (RXRα) as a key integrator of host resilience during polymicrobial sepsis. RXRα is transcriptionally regulated by hepatocyte nuclear factor 4α (HNF4α), and sepsis rapidly decreases RXRα mRNA and protein levels. Transcriptomic analyses show that the septic liver becomes partially resistant to pharmacological activation of RXRα with bexarotene. Prophylactic- but not therapeutic- bexarotene improves survival by preserving metabolic stability and enhancing bacterial clearance. In hepatocyte-specific inducible RXRα-deficient mice, this protection is lost, confirming dependence on hepatocyte RXRα. Loss of RXRα in hepatocytes reduces Kupffer cell numbers, resulting in bacterial dissemination and mortality, a phenotype reproduced in a genetic model of selective Kupffer cell ablation. Overall, RXRα maintains the hepatic macrophage niche, linking hepatocellular transcriptional competence to systemic antibacterial defense.

This errata corrects the omission of a relevant reference in the main text of our recent paper [ Biomed. Opt. Express 17 , 1953 ( 2026 ) 10.1364/BOE.587556 ], clarifies a sentence in the Introduction to reflect prior work only on time-domain FLI and tumor delineation accuracy, and adds a related clarification in the Discussion. In addition, Fig. 3 has been adapted. These changes do not affect the results or conclusions of the article.

The chick chorioallantoic membrane (CAM) assay is an in vivo metastasis model, yet traditional Alu-qPCR quantification suffers from non-specific background noise in avian tissue. To improve analytical specificity, we developed a species-specific digital PCR (dPCR) assay targeting the human mitochondrial locus MT-ND4. While Alu-qPCR generated false positives in chicken-only DNA, MT-ND4 dPCR provided absolute specificity and robust absolute quantification of human HT-1080 cells across various embryonic organs. Mixed-effects modeling confirmed significant organ-specific metastatic patterns (p < 0.001) with high precision. This MT-ND4 dPCR assay avoids false-positive overestimations, providing a superior tool for quantifying metastatic burden in the CAM model.

Indocyanine green (ICG) is used for tumor visualization using fluorescence-intensity imaging, but false-positive signals are common. Fluorescence-lifetime-based tumor identification may overcome this limitation by measuring the time behavior of fluorescent light. However, the optimal time point for fluorescence lifetime imaging after the intravenous administration of ICG is yet to be defined. In this paper, the in vivo time course of ICG is investigated in syngeneic tumor-bearing mice using a novel macroscopic fluorescence lifetime camera. High-dynamic-range images were generated through post-processing, investigated, and subsequently applied for time-domain intensity and lifetime image analysis. The results indicate that fluorescence lifetime imaging may provide higher accuracy in tumor identification than intensity-based imaging, but the optimal imaging time point appears to require a 24-48 hour interval after intravenous injection, similar to intensity measurements. However, earlier time points might be of interest to investigate for liver and intestinal tumors.

Hemangiosarcoma (HSA) in dogs is a malignant vascular tumour that exhibits rapid growth, frequent early metastasis, and resistance to conventional therapies, often resulting in short survival times. Building on our previous systematic review of biomarkers in human angiosarcoma, this review focuses specifically on the canine counterpart, synthesizing current evidence on diagnostic, prognostic, and therapeutic biomarkers. A comprehensive PRISMA‐compliant search of PubMed and Embase was conducted for studies published from 1996 through 2024, inclusive. Fifty‐one eligible studies were identified and assessed for methodological quality using the Newcastle–Ottawa Scale. This review highlights promising protein, molecular, and haematological biomarker candidates, evaluates their clinical relevance, and identifies key gaps in the literature and existing knowledge. By drawing parallels to human angiosarcoma research, this work lays the foundation for comparative oncology efforts and supports the development of novel diagnostic tools and targeted therapies for canine HSA.

Objectives: It is often suggested in the literature that the anatomy of the extrahepatic portal vein (EHPV) in dogs and cats is similar. Nevertheless, variations and contradictions in the tributaries of the EHPV in cats have been described. Therefore, the aim of this study was to describe the normal anatomical variations of the tributaries of the EHPV in a large cohort of cats. Methods: A retrospective, descriptive, cross-sectional study of abdominal CT angiography (CTA) scans was performed. Cats that underwent CTA between January 2020 and July 2024 were reviewed in consensus by three observers. Cats with vascular anomalies or CTA scans in which the EHPV or its tributaries could not be accurately evaluated were excluded. Results: A total of 52 CTA scans were included. The splenic vein (SV) was consistently present in all cats as the most caudally inserting vein in the EHPV. The left gastric vein (LGV) entered the EHPV directly in 42/52 cats and, in 36 of those, the LGV was the most cranial vein entering the EHPV. In 28 cats with direct insertion, a second branch of the LGV entered the SV. In eight cats, a single LGV entered the SV, as is typically seen in dogs. In the remaining two cats, the LGV was not identified. In 34/52 cats, the gastroduodenal vein entered the EHPV, as described in dogs, whereas in the remaining 18 cats, the right gastric vein and cranial pancreaticoduodenal vein entered the EHPV together. Conclusions and relevance: Various anatomical variations of the inserting veins in the EHPV were identified. Knowledge about the variation in normal anatomy of the EHPV and its tributaries is important, especially to evaluate complex pathologies of the EHPV, such as vascular anomalies and EHPV thromboses.

Objective: To evaluate the soft palate thickness in brachycephalic dogs 3 months after performing folded flap palatoplasty (FFP) or standard staphylectomy (STS). Study design: Prospective, observational study. Animals: Twenty client‐owned dogs with brachycephalic obstructive airway syndrome undergoing corrective multilevel upper airway surgery. Methods: Clinical examination consisted of an exercise tolerance test (ETT) and evaluation of the oropharynx and larynx. Computed tomography (CT) of the skull was performed to measure the length (LEN), rostral thickness (RTH), and middle thickness (MTH) of the soft palate, with calculations of the longitudinal cross‐sectional area (CSA) and palatal volume (VOL). Dogs were assigned to undergo FFP ( n = 10) or STS ( n = 10). Examinations were repeated 3 months postoperatively. Results: The ETT score 3 months postoperatively improved in 6/8 dogs in the FFP group and in 10/10 dogs in the STS group. Shortening of the soft palate resulted in reduction of the median LEN, CSA, and VOL after both FFP and STS. Median rostral thickness increased by 8.2% (IQR −2.0 to 20.6) after FFP and by 10.1% (IQR 1.0 to 15.7) after STS. Median middle thickness increased by 7.9% (IQR −5.0 to 20.9) after FFP and decreased by 16.9% (IQR −27.0 to −0.4) after STS. Conclusion: Folded flap palatoplasty did not result in decreased soft palate thickness in the dogs in this study when evaluated by CT 3 months postoperatively. Clinical significance: Folded flap palatoplasty and STS both resulted in postoperative clinical improvement. Future studies, including a CT immediately postoperatively, could indicate whether the soft palate is thinned immediately after FFP.

Objectives: Cytology is a common diagnostic tool in veterinary practice, and canine mast cell tumours are presumed to be easy to diagnose. However, the potential influence of the observer's educational attainment on the interobserver agreement when interpreting representative images of cytological smears has not yet been investigated. Materials and Methods: In total, 25 observers were equally divided into five groups based on educational attainment (board‐certified diplomates of the European College of Veterinary Surgeons specialised in companion animals, board‐certified of the European College of Veterinary Internal Medicine‐Companion animals, general practitioners, interns and final‐year veterinary medicine students) and asked to evaluate 36 distinct sets of images from cytological smears, of which 18 originated from canine mast cell tumours and 18 from non‐mast cell tumours. No additional training was given. The interobserver agreement and kappa were calculated. Results: For mast cell tumour diagnosis and mast cell presence, eosinophils and lymphocytes, specialists in internal medicine had the highest interobserver agreement, whereas interns or final‐year students had the lowest. Differences in interobserver agreement were significant for mast cell tumour diagnosis and the presence of mast cells. Clinical Significance: Our results emphasize the importance of training to improve the consistency of classifying cytological smears as mast cell tumours or not.

Objective: To report 30‐day survival of cats that experienced postattenuation neurologic signs (PANS) after surgical attenuation of a single congenital portosystemic shunt (cPSS), and to investigate prognostic factors for short‐term survival.Study design: Multi‐institutional retrospective study.Sample population: A total of 59 cats with cPSS that experienced PANS.Methods: The medical records of 10 institutions were retrospectively reviewed to identify cats that underwent cPSS attenuation from January 1, 2010 through June 30, 2023 and developed PANS within 7 days postoperatively. Exclusion criteria were cats with arteriovenous malformation and cats lost‐to‐follow‐up prior to 30 days. Logistic regression identified factors associated with 30‐day survival. Odds Ratios (OR) and 95% CIs were calculated.Results: A total of 46 (78.0%) PANS‐affected cats survived to 30 days. A total of 13 (50.0%) of 26 cats that experienced postattenuation seizures (PAS) survived to 30 days, with most non‐surviving cats experiencing generalized PAS. Cats that experienced PAS (p < .01, OR: 0.015, 95% CI: p < .01, OR: 0.112, 95% CI: 0.022–0.569) were associated with decreased odds of 30‐day survival.Conclusion: Most cats that experienced PANS survived to 30 days; however, short‐term survival rate was worse for cats that experienced PAS.Clinical significance: The prognosis for cats that experience PANS is generally good but experiencing PAS and requiring treatment with propofol are negative prognostic factors.

The enzyme poly (ADP‐ribose) polymerase‐1 (PARP‐1) is crucial for cellular regulation and DNA repair. Its immunohistochemical overexpression is known in various human neoplasms, but it was not yet a topic of veterinary research. Formalin‐fixed paraffin‐embedded canine samples of 15 controls and 34 tumours were immunohistochemically tested for PARP‐1 expression. Controls included five skin samples with mast cells, five oral mucosa samples and five thyroid glands. Tumours included 18 mast cell tumours (MCTs), 10 oral squamous cell carcinomas (SCCs) and six follicular thyroid carcinomas. A board‐certified veterinary pathologist defined the optimal region for the blind PARP‐1 evaluation, assessed by two independent veterinary PhD students. Positive nuclei were evaluated by the immunoreactivity score (IRS) and quick score (QS) and, for both scores, the averages of the two observers were used for statistical analysis. In all MCTs, 6/10 SCCs and all thyroid carcinomas as well as four thyroid controls a nuclear expression was observed. A cytoplasmic granular staining was visible in all dermal mast cells and in 11/18 MCTs due to non‐specific antibody uptake. No PARP‐1 was expressed in 11/15 controls.Compared to the controls, thyroid carcinomas significantly overexpressed PARP‐1 when calculated by IRS and QS (p = 0.003 and p = 0.005, respectively). The latter also applied to the MCTs (p = 0.001). A significantly higher PARP‐1 IRS and QS were observed in thyroid carcinomas (p = 0.003, p = 0.005) and MCTs (p = 0.003, p = 0.012) compared to oral SCCs. The immunohistochemical PARP‐1 overexpression in these tumours invites further research to assess its potential as a therapeutic target.