Choline-deficient, high-fat diet-induced MASH in Göttingen Minipigs: characterization and effects of a chow reversal period.

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH) is increasing, and translational animal models are needed to develop novel treatments for this disease. The physiology and metabolism of pigs have a relatively high resemblance to humans, and the present study aimed to characterize choline-deficient and high-fat diet (CDAHFD)-fed Göttingen Minipigs as a novel animal model of MASLD/MASH. Göttingen Minipigs were fed CDAHFD for up to 5 mo, and the phenotype was investigated by the analysis of plasma parameters and repeated collection of liver biopsies. Furthermore, changes in hepatic gene expression during the experiment were explored by RNA sequencing. For a subset of the minipigs, the diet was changed from CDAHFD back to chow to investigate whether the liver pathology was reversible. Göttingen Minipigs on CDAHFD gained body weight, and plasma levels of cholesterol, AST, ALT, ALP, and GGT were increased. CDAHFD-fed minipigs developed hepatic steatosis, inflammation, and fibrosis, which in 5 of 16 animals progressed to cirrhosis. During an 11-wk chow reversal period, steatosis regressed, while fibrosis persisted. Regarding inflammation, the findings were less clear, depending on the type of readout. MASH Human Proximity Scoring (combined evaluation of transcriptional, phenotypic, and histopathological parameters) showed that CDAHFD-fed Göttingen Minipigs resemble human MASLD/MASH better than most rodent models. In conclusion, CDAHFD-fed minipigs develop a MASH-like phenotype, which, in several aspects, resembles the changes observed in human patients with MASLD/MASH. Furthermore, repeated collection of liver biopsies allows detailed characterization of histopathological changes over time in individual animals.NEW & NOTEWORTHY The physiology and metabolism of pigs have a relatively high resemblance to humans. This study characterizes a new animal model of MASLD/MASH using CDAHFD-fed Göttingen Minipigs. Göttingen Minipigs fed CDAHFD gained weight and developed hepatic steatosis, inflammation, fibrosis, and cirrhosis. After an 11-wk chow-reversal period, hepatic steatosis and some inflammatory parameters reversed. Combined evaluation of phenotypic, transcriptional, and histological parameters revealed the minipig model showed a higher resemblance to human disease than many rodent models.

Survey among FELASA members about rehoming of animals used for scientific and educational purposes.

Rehoming is an important fate, which should be considered for animals used for scientific and educational purposes, and which is highlighted in the European Directive 2010/63 EU. In 2018, the Federation of European Laboratory Animal Science Associations (FELASA) convened a working group to review current literature and identify existing practices with the aim of issuing general recommendations on the rehoming of research animals. In order to understand the number and species of animals being rehomed and which species and information to include in the recommendations, the working group launched a survey that was distributed among FELASA members, yielding 97 valid records for analysis. Most respondents of the survey considered the rehoming of cats, dogs, mice, rats, rabbits, pigs and minipigs. The most important issues reported by the respondents were related to availability/suitability of animals, availability of adopters and legal issues. Based on the data and information collected in this survey, the working group decided on the format and content of the future recommendations: a first section containing a general protocol for rehoming, addressing the issues raised by the respondents, and a second section containing species-specific information and advice about cats, dogs, small prey mammals, equines, primates, camelids and minipigs.

FELASA recommendations for the rehoming of animals used for scientific and educational purposes.

Directive 2010/63/EU of the European Parliament and the Council of 22 September 2010 states that at the end of a procedure, the most appropriate decision on the future of an animal previously used or intended for use in scientific procedures should be taken on the basis of animal welfare and potential risks to the environment. Member States may allow animals to be rehomed provided the health of the animal allows it, there is no danger to public health, animal health or the environment and if appropriate measures have been taken to safeguard the wellbeing of the animal. In countries where rehoming is permitted, it is the responsibility of the Animal Welfare Body to advise on a rehoming scheme which must include appropriate socialization in order to help facilitate successful rehoming, avoid unnecessary distress to the animals and guarantee public safety. This paper reviews the EU legislation, existing guidance, current literature and best practice to define rehoming, sets out general considerations for rehoming laboratory animals including socialization and provides practical advice on the steps required in a rehoming scheme. For those species most frequently rehomed, more detailed species-specific sections are included.

A genetically modified minipig model for Alzheimer's disease with SORL1 haploinsufficiency.

The established causal genes in Alzheimer's disease (AD), APP, PSEN1, and PSEN2, are functionally characterized using biomarkers, capturing an in vivo profile reflecting the disease's initial preclinical phase. Mutations in SORL1, encoding the endosome recycling receptor SORLA, are found in 2%-3% of individuals with early-onset AD, and SORL1 haploinsufficiency appears to be causal for AD. To test whether SORL1 can function as an AD causal gene, we use CRISPR-Cas9-based gene editing to develop a model of SORL1 haploinsufficiency in Göttingen minipigs, taking advantage of porcine models for biomarker investigations. SORL1 haploinsufficiency in young adult minipigs is found to phenocopy the preclinical in vivo profile of AD observed with APP, PSEN1, and PSEN2, resulting in elevated levels of ß-amyloid (Aß) and tau preceding amyloid plaque formation and neurodegeneration, as observed in humans. Our study provides functional support for the theory that SORL1 haploinsufficiency leads to endosome cytopathology with biofluid hallmarks of autosomal dominant AD.

Fasting of male mice - Effects of time point of initiation and duration on clinical chemistry parameters and animal welfare.

Fasting of mice is a common procedure, which can affect the outcome of the study as well as animal welfare. In this study, we assess the effects of fasting, fasting duration and fasting initiation time in relation to light schedule and present suggestions for optimization of fasting. Male C57BL/6NCrl mice were fasted for 0, 3, 6, 12, 18 and 24 hours initiated either in the light period (photophase) or the dark period (scotophase). Body weight, gastric content, body temperature, corticosterone and 19 routine clinical chemistry parameters were evaluated. Fasting caused significant changes in most of the measured parameters. Increasing duration of fasting resulted in increasing physiological changes. Fasting initiated in the scotophase caused more significant changes than fasting initiated in the photophase. To cause the least physiological changes in mice and increase animal welfare, mice should preferably be fasted in the photophase and for the shortest possible period allowed by the experimental purpose of fasting.

Canine serum C-reactive protein as a quantitative marker of the inflammatory stimulus of aseptic elective soft tissue surgery.

BACKGROUND: C-reactive protein (CRP) is an established serum marker for the presence of systemic inflammation in dogs. Results from previous experimental and clinical studies suggest that CRP concentrations also quantitatively reflect the degree and progress of an inflammatory process, suggesting its use for inflammation monitoring. OBJECTIVES: The objective was to investigate whether the canine CRP response in serum correlates with the amount of trauma and the consequent inflammatory response after 3 standard aseptic soft-tissue surgical procedures in 3 groups of dogs. METHODS: A total of 24 client-owned intact female dogs of various breeds were enrolled in a clinical study with random allocation into 2 surgical groups, for either conventional, open-approach ovariohysterectomy (OVH; n = 14) or laparoscopic assisted OVH (n = 10). In addition, a group of 8 male Beagles from a laboratory animal facility underwent vasectomy, serving as the third and mildest surgical trauma group. Serum CRP was measured pre- and at 4, 8, 12, 23, and 27 hours postsurgery. Cumulative concentration over time and point concentrations of CRP were correlated with the surgical trauma impact level. RESULTS: There was a significant surgery trauma-related difference in cumulative CRP concentrations among the 3 groups, and also in the 12 hours postsurgery concentration. CONCLUSION: The CRP response varied according to the degree of surgical trauma on 3 standardized levels, thus supporting the use of canine serum concentrations of CRP as an inflammatory activity indicator and monitoring marker.