Background: The pig is one of the most frequently used large animal models for biomedical research, especially in the field of translational research and surgical models. While standard livestock breeds are used in short-term and acute studies, minipig breeds are the preferred breeds in long-term and chronic studies due to their limited growth and body weight. Objective: In consideration of the 3R principle (refinement, reduction, replacement) and the increasing demand, the aim of this study was to generate a new, robust, non-specific-pathogen-free minipig breed, the Aachen minipig. Methods: Phenotype, genotype, and hematological as well as clinical chemistry parameters were characterized, and reference values of the Aachen minipig were generated and compared to the values in the commonly used Göttingen minipig. Organ weights of the heart, kidney, liver, lung, spleen, and brain were determined using a laboratory balance. Blood samples were collected for hematology and clinical chemistry. Assessment of genetic diversity was performed by microsatellite markers. Nasal swabs were collected from 11 individual minipigs representing 6 races for DNA extraction. DNA was quantified and the identity and origin of the Aachen minipigs at the genomic level was determined by microsatellites. Results: The Aachen minipig established here is based on the Mini-LEWE breed and consists of the Vietnamese potbelly pig, the Schwäbisch Hällisch Landpig, the German Landrace, and the Minnesota minipig. Relative organ weights (lung, heart, kidneys, brain), hematology (hemoglobin, hematocrit, platelet count, mean corpuscular hemoglobin concentration, segmented neutrophils, lymphocytes, eosinophils, basophils), and clinical chemistry parameters (sodium, calcium, chloride, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transferase, lactate dehydrogenase, triglycerides, blood urea nitrogen, creatinine, total bilirubin, total protein, creatine kinase) of the Aachen minipigs and the Göttingen minipigs were not significantly different. Significant differences where only seen in relative organ weights (liver, spleen), hematology (red blood cell count, mean corpuscular volume, mean corpuscular hemoglobin, white blood cell count, banded neutrophils, monocytes), and clinical chemistry parameters (inorganic phosphorus, potassium, glucose, cholesterol, albumin, amylase). Conclusion: The Aachen minipig is a suitable model for research due to its similarity to other minipig breeds, especially the Göttingen minipig. The reference values established in this study may be used for the comparison of scientific data and encourage the use of the Aachen minipig as an animal model for biomedical research.

Score sheets were first introduced 30 years ago to assess pain, distress and suffering in animals. To date, however, there is still no general agreement on their use in research practice, and only a few publications can be found on this topic. In the present work, we demonstrate the use of a special score sheet for severity assessment in the first three postoperative days in two showcased studies performed on Wistar and Lewis rats undergoing liver resection or orthotopic liver transplantation, respectively. Scoring of different criteria and the total score were evaluated within each intervention. Additionally, both procedures were compared regarding their degree of severity. Suitability of these score sheets was evaluated for assessing severity of the procedures and these showed a minor severity within each investigated study. A comparison of both studies showed slightly higher scores involving liver transplantation. In contradiction to the common classification of these procedures as a moderate severity grade the score sheets applied here indicates a minor severity grade within each investigated study. Also, limitations and possible improvements in the design of our score sheets for defined interventions are reconsidered.

Background: Topical hemostatic agents are useful when hepatic hemorrhage is difficult to control. The aim of this study was to evaluate the hemostatic efficacy and safety of a biodegradable polyurethane-based adhesive, MAR VIVO-107 (MAR), in comparison with a clinically used fibrin glue. Methods: Thirty female New Zealand white rabbits were randomly assigned to 3 study groups as follows: MAR (n = 10), fibrin glue (n = 10), and saline groups (n = 10). After standardized partial liver resection was performed, each agent was immediately applied to the wound area. Bleeding time until hemostasis and blood loss were recorded. After 7 days, body weight, hematology parameters, and serum levels of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase were measured. Simultaneously, the severity of intra-abdominal adhesion was evaluated. Results: The mean bleeding time in the MAR (38 ± 10 s) and fibrin glue groups (65 ± 17 s) was significantly shorter than that in the saline group (186 ± 12 s). Similarly, the mean blood loss in the MAR (9 ± 3 g) and fibrin glue groups (9 ± 3 g) was significantly less than that in the saline group (23 ± 4 g). No significant differences in bleeding time and blood loss were found between the MAR and fibrin glue groups. The postoperative survival rate was 100% in all the groups. Body weight as well as hematological and serum biochemical values on day 7 were within the small and physiological range when compared with the preoperative baseline values, and significant differences were not detected among the MAR, fibrin glue, and saline groups. The severities of adhesion were similar between the 3 groups. Conclusion: Our data demonstrated that MAR was not inferior to fibrin glue in terms of hemostatic efficacy and safety.

The efficacy of MAR-VIVO-107 and comparable performance to the gold standard fibrin have been shown under pre-clinical conditions. MAR-VIVO-107 permits hemorrhage control within seconds, even in wet environment.