Efficacy of the porcine species in biomedical research

Scaling factors to inform in vitro-in vivo extrapolation from preclinical and livestock animals: state of the field and recommendations for development of missing data

The use of in-vitro-in-vivo physiologically based pharmacokinetic (IVIVE-PBPK) modeling approaches assists for prediction of first-in animal or human trials. These approaches are underpinned by the scaling factors: microsomal protein per gram (MPPG) and cytosolic protein per gram (CPPG). In addition, IVIVE-PBPK has significant application in the reduction and refinement of live animal models in research. While human scaling factors are well-defined, many preclinical and livestock species remain poorly elucidated or uncharacterized. The MPPG parameter for liver (MPPGL) is the best characterized across all species and is well-defined for mouse, rat, and dog models. The MPPG parameters for Kidney (MPPGK) and intestine (MPPGI), are however; relatively indefinite for most species. Similarly, CPPG scaling factors for liver, kidney, and intestine (CPPGL/CPPGK/CPPGI) are generally sparse in all species. In addition to generation of mathematical values for scaling factors, methodological and animal-specific considerations, such as age, sex, and strain differences, have not yet been comprehensively described. Here, we review the current state-of-the-field for microsomal and cytosolic scaling factors, including highlighting areas that may need further description and development, with the intention of drawing attention to key knowledge gaps. The intention is to promote improved accuracy and precision in IVIVE-PBPK, concordance between laboratories, and stimulate work in underserved, but increasingly vital areas.

Hematological reference intervals for Danish crossbred Landrace Yorkshire Duroc (LYD) pigs used in biomedical research

BACKGROUND

The health and welfare of pigs used in biomedical research is essential to research quality and compliance with the 3Rs (replacement, reduction, and refinement). Hematological variables are objective markers to quantitatively determine health issues and evaluate physiological differences before and after experimental procedures. There are no recent validated hematologic reference intervals (RIs) published for Danish crossbred Landrace Yorkshire Duroc (LYD) pigs to aid researchers and veterinarians in their decision-making. The objective of this study was to establish hematologic RIs for LYD pigs used for biomedical research. Blood samples were collected from healthy female LYD pigs (35-65 kg) and analyzed using the in-house ProCyte Dx Hematology Analyzer. Means with 90% confidence intervals for lower and upper limits were calculated according to guidelines by the American Society of Veterinary Clinical Pathology.

RESULTS

Inspection of 141 pigs led to 133 blood samples available for analyses after exclusions due to clinical signs of disease, inadequate tube filling or presence of macroscopic clots. Thirty-two samples reported platelet abnormalities and upon further investigation these samples were excluded when calculating RIs for platelets and platelet indices. Other measurements were not affected. The RI for red blood cells, hemoglobin, hematocrit and white blood cells were 5.10-7.00 × 106/µL, 9.36-12.29 g/dL, 30.46-40.47%, and 11.73-25.00 × 103/µL, respectively.

CONCLUSIONS

Our study provides RIs for hematological variables in LYD pigs, revealing significant differences from published RIs of other breeds. These findings highlight the influence of factors like age, breed and health status on measurements, emphasizing the importance of using breed-specific RIs. This research supports the 3Rs, guiding better animal care and enhancing overall research quality.

Evolving adeno-associated viruses for gene transfer to the kidney via cross-species cycling of capsid libraries

The difficulty of delivering genes to the kidney has limited the translation of genetic medicines, particularly for the more than 10% of the global population with chronic kidney disease. Here we show that new variants of adeno-associated viruses (AAVs) displaying robust and widespread transduction in the kidneys of mice, pigs and non-human-primates can be obtained by evolving capsid libraries via cross-species cycling in different kidney models. Specifically, the new variants, AAV.k13 and AAV.k20, were enriched from the libraries following sequential intravenous cycling through mouse and pig kidneys, ex vivo cycling in human organoid cultures, and ex vivo machine perfusion in isolated kidneys from rhesus macaques. The two variants transduced murine kidneys following intravenous administration, with selective tropism for proximal tubules, and led to markedly higher transgene expression than parental AAV9 vectors in proximal tubule epithelial cells within human organoid cultures and in autotransplanted pig kidneys. Following ureteral delivery, AAV.k20 efficiently transduced kidneys in pigs and macaques. The AAV.k13 and AAV.k20 variants are promising vectors for therapeutic gene-transfer applications in kidney diseases and transplantation.

Gene Editing for Enhanced Swine Production: Current Advances and Prospects

Traditional pig breeding has improved production traits but faces limitations in genetic diversity, disease resistance, and environmental adaptation. Gene editing technologies, such as CRISPR/Cas9, base editing, and prime editing, enable precise genetic modifications, overcoming these limitations and expanding applications to biomedical research. Here, we reviewed the advancements in gene editing technologies in pigs and explored pathways toward optimized swine genetics for a resilient and adaptive livestock industry. This review synthesizes recent research on gene editing tools applied to pigs, focusing on CRISPR/Cas9 and its derivatives. It examines their impact on critical swine production traits and their role as human disease models. Significant advancements have been made in targeting genes for disease resistance, such as those conferring immunity to porcine reproductive and respiratory syndrome viruses. Additionally, gene-edited pigs are increasingly used as models for human diseases, demonstrating the technology's broader applications. However, challenges such as off-target effects, ethical concerns, and varying regulatory frameworks remain. Gene editing holds substantial potential for sustainable and productive livestock production by enhancing key traits and supporting biomedical applications. Addressing technical and ethical challenges through integrated approaches will be essential to realize its full potential, ensuring a resilient, ethical, and productive livestock sector for future generations.

Swine clones: potential application for animal production and animal models

Somatic cell nuclear transfer (SCNT), or cloning, is used to reprogram cells and generate genetically identical embryos and animals. However, the cloning process is inefficient, limiting its application to producing valuable animals. In swine, cloning is mainly utilized to produce genetically modified animals. Indeed, recombinant DNA technologies have evolved considerably in recent years, with homologous recombination and gene editing technologies becoming more efficient and capable of recombining both alleles in a single cell. The selection of appropriate cells and their use as nuclear donors for SCNT is the most common method for generating edited and genetically modified animals for commercial and research purposes. This article reviews current applications of swine cloning and shares our personal experiences with the procedure in this species.

Use of Transcriptomics to Identify Candidate Genes for Hematopoietic Differences Between Wujin and Duroc Pigs

Hematopoiesis is a complex physiological process that ensures renewal of blood cells to maintain normal blood circulation and immune function. Wujin pigs exhibit distinct characteristics such as tender meat, high fat storage, strong resistance to roughage, robust disease resistance, and oxidation resistance. Therefore, using Wujin pigs as models may offer valuable insights for hematopoietic-related studies. In this study, twelve healthy 35-day-old piglets, including six Wujin and six Duroc piglets of similar weight, were selected from each of the Wujin and Duroc pig groups and housed in single cages. After 30 days of feeding, blood and bone marrow samples were collected. Routine blood indices and hematopoietic-related serum biochemical indexes of Wujin and Duroc pigs were determined, and bone marrow gene expression levels were analyzed using transcriptomics. (1) Hemoglobin (Hb) and Mean Corpuscular Hemoglobin Concentration (MCHC) levels in Wujin pigs were significantly higher than in Duroc pigs (p < 0.05), and platelet counts and serum Hb levels in Wujin pigs were significantly lower than in Duroc pigs (p < 0.05). (2) A total of 312 significantly differentially expressed genes were identified between the pigs. Their functions were mainly related to blood systems, inflammation, and oxidation. Six differentially expressed genes may be related to hematopoietic function. (3) By combining the differential genes screened through sequencing with Weighted Gene Co-expression Network Analysis results, 16 hematopoietic function differential genes were obtained, mainly focusing on immunity, inflammation, and induction of apoptosis functions. Differences were present in the immune and inflammatory responses between Wujin pigs and Duroc pigs, suggesting that differences in hematopoietic function between the two breeds were related to antioxidant capacity and disease resistance.

Metabolic profile and glycemic response in fully-grown sows born using assisted reproductive technologies

The aim of the present work was to gain insight into the metabolism of pigs derived from assisted reproductive technologies during their adulthood. Approximately 4h after feeding, a blood sample was taken from 3.5 year old sows born by artificial insemination (AI group, n = 7) and transfer of in vitro produced embryos (IVP group, n = 11) to determine the physiological concentrations of the main biomarkers of carbohydrates (glucose and lactate), proteins (albumin, creatinine and urea) and lipids (cholesterol and triglycerides). Four weeks later, an oral glucose tolerance test (OGTT; 1.75g glucose/kg body weight) was performed after an overnight fast and 1h of water withdrawal. Blood samples were obtained prior (T = 0 min; fasting conditions) and 15, 30, 45, 60, 90, 120, 150, 180, 210 and 240 min after glucose intake. At each time point, glycemia was measured immediately using glucometer test strips, and serum was collected to determine the above metabolites along with insulin and glucagon. After OGTT, the area under the curve (AUC) between sampling times and homeostasis model assessment of insulin resistance (HOMA) indices were calculated. Under physiological conditions, the concentration of metabolites studied was similar between AI and IVP sows. In both groups, fasting decreased cholesterol and increased triglycerides and urea (P < 0.001). However, creatinine and lactate were similar in both groups under physiological and fasting conditions. The expected increase in albuminemia and decrease in glycaemia after fasting was only observed in IVP sows. OGTT revealed a different glucose curve pattern (monophasic in AI and biphasic in IVP group), a lower mean concentration of cholesterol, glucose, lactate, triglycerides in IVP compared to AI pigs (P < 0.01), and a higher mean concentration of albumin, creatinine and insulin in IVP compared to AI group (P < 0.05). On the contrary, no differences were found between groups for mean serum glucagon and urea levels, nor for glucose homeostasis indices HOMA-IR and HOMA-%B. The AUC differed between groups at several time points with larger AUC for creatinine, and smaller AUC for glucose, glucagon, and triglycerides, in IVP pigs than in AI pigs at 180-210 min (P < 0.05). In conclusion, under physiological conditions the metabolic profile of fully-grown AI and IVP sows is similar and within normal ranges. Glucose challenge revealed differences in metabolic and insulin responses between groups but with normal glucose tolerance in both cases.

Investigating the Influence of a Tooth Absence on Facial Bone Growth Using a Porcine Model

With the current state of knowledge regarding disorders of facial bone development, including anodontia, the development of a suitable animal model for preclinical studies is essential. The agenesis of dental buds occurs in about 25% of the human population. Prospects for treatment include the use of growth factors, stem cells, and bioengineering. This study aimed to investigate the influence of a tooth absence on facial bone growth, develop a technique for the application of growth factors to the developing bone, and analyze the comparative effect of the application of selected active proteins on the growth of the maxilla and mandible. Piglets underwent germectomy, followed by computed tomography and X-ray; morphometric and histological analyses of the bones were performed, blood bone morphogenetic protein 2 and platelet-derived growth factor concentrations were determined, and the transcriptomic profile of the dentate ligament was analyzed using DNA microarrays. It was not possible to identify the most effective growth factor application algorithm for achieving normal jaw development. Normal mandibular bone structure and oral mucosa structure were observed in the germectomy groups with growth factor augmentation. The average height of the mandibular alveolar part in the area of the removed dental buds was significantly lower compared with that of the inoperable side, 3 months after surgery. However, no significant differences were found in the serum concentrations of BMP-2 and PDGF between groups. The animal model of bone development disorders (including anodontia) developed in the current study and the scheme for evaluating the efficacy and safety of the application of replacement therapy for craniofacial malformations are important in the development of the discipline and represent an important contribution to the introduction of treatment methods.

Single-cell analysis of nasal epithelial cell development in domestic pigs

The nasal mucosa forms a critical barrier against the invasion of respiratory pathogens. Composed of a heterogeneous assortment of cell types, the nasal mucosa relies on the unique characteristics and complex intercellular dynamics of these cells to maintain their structural integrity and functional efficacy. In this study, single-cell RNA sequencing (scRNA-seq) of porcine nasal mucosa was performed, and nineteen distinct nasal cell types, including nine epithelial cell types, five stromal cell types, and five immune cell types, were identified. The distribution patterns of three representative types of epithelial cells (basal cells, goblet cells, and ciliated cells) were subsequently detected by immunofluorescence. We conducted a comparative analysis of these data with published human single-cell data, revealing consistent differentiation trajectories among porcine and human nasal epithelial cells. Specifically, basal cells serve as the initial stage in the differentiation process of nasal epithelial cells, which then epithelial cells. This research not only enhances our understanding of the composition and transcriptional signature of porcine nasal mucosal cells but also offers a theoretical foundation for developing alternative models for human respiratory diseases.

OMIP-107: 8-color whole blood immunophenotyping panel for the characterization and quantification of lymphocyte subsets and monocytes in swine

We developed this whole blood immunophenotyping panel with the aim to monitor and quantify major lymphocyte subsets (CD4+, CD8+, CD4+CD8+ αβ T cells, γδ-T cells, B and NK cells) and monocytes in pigs. The panel involved the use of commercially available reagents, avoiding secondary antibody staining or in-house antibody conjugations, with the aim to make the assay accessible and reproducible across laboratories. The assay is accurate, robust and represents a useful tool for immune monitoring of swine in the pharmacology and toxicology fields, or to monitor the immune status in response to vaccination and diseases.

Clicker Training in Minipigs to Reduce Stress during Blood Collection-An Example of Applied Refinement

Pigs (and minipigs) are often restrained with a maxillary sling for blood collection. They mainly produce strong vocalisations and show resistance to the procedure, which subjectively appears to be stressful for the animals. The present study investigated whether minipigs can be trained to tolerate aversive stimuli and whether training can reduce stress during blood collection. Blood was taken from 12 Ellegaard minipigs with fixation; thereafter, the animals were trained for 3 weeks using clicker training. Then, blood was taken again, but without fixation. Before and after each blood sample, saliva samples were taken. The cortisol concentration was determined using ELISAs. Serum cortisol was not significantly different before and after training (paired-sample t-test, t (9) = 2.052, p = 0.07). However, salivary cortisol was significantly lower after training (ANOVA (analysis of variance), p-value < 0.001, F-value 6.181). In addition, trained minipigs showed a significantly lower heart rate after blood sampling (paired-sample t-test, t (11) = 4.678, p = 0.001) as well as significantly lower heart rate variability (t (11) = 3.704, p = 0.003) compared to before training. The minipigs could be trained to tolerate aversive stimuli. This contributed to stress reduction when taking blood samples.

The Future Exploring of Gut Microbiome-Immunity Interactions: From In Vivo/Vitro Models to In Silico Innovations

Investigating the complex interactions between microbiota and immunity is crucial for a fruitful understanding progress of human health and disease. This review assesses animal models, next-generation in vitro models, and in silico approaches that are used to decipher the microbiome-immunity axis, evaluating their strengths and limitations. While animal models provide a comprehensive biological context, they also raise ethical and practical concerns. Conversely, modern in vitro models reduce animal involvement but require specific costs and materials. When considering the environmental impact of these models, in silico approaches emerge as promising for resource reduction, but they require robust experimental validation and ongoing refinement. Their potential is significant, paving the way for a more sustainable and ethical future in microbiome-immunity research.

Swine models in translational research and medicine

Swine are increasingly studied as animal models of human disease. The anatomy, size, longevity, physiology, immune system, and metabolism of swine are more like humans than traditional rodent models. In addition, the size of swine is preferred for surgical placement and testing of medical devices destined for humans. These features make swine useful for biomedical, pharmacological, and toxicological research. With recent advances in gene-editing technologies, genetic modifications can readily and efficiently be made in swine to study genetic disorders. In addition, gene-edited swine tissues are necessary for studies testing and validating xenotransplantation into humans to meet the critical shortfall of viable organs versus need. Underlying all of these biomedical applications, the knowledge of husbandry, background diseases and lesions, and biosecurity needs are important for productive, efficient, and reproducible research when using swine as a human disease model for basic research, preclinical testing, and translational studies.

Maximizing insights from nonclinical safety studies in the context of rising costs and changing regulations

The traditional paradigm of non-rodent safety assessment studies, primarily reliant on non-human primates (NHPs) and dogs, is undergoing a transformation. During the 2023 Safety Pharmacology Society Annual Meeting, scientists from leading nonclinical contract organizations discussed how traditional IND-enabling studies can benefit from employing underutilized alternative non-rodent models, such as the swine. Swine offer a cost-effective approach to drug development and share many anatomical and physiological similarities with humans. The inclusion of non-traditional species in safety assessments, coupled with advanced measurement techniques, aids in de-risking compounds early on and adapting projects to the evolving cost landscape.

Pigs as Clinically Relevant Models for Synergizing Interventional Oncology and Immunotherapy

Traditionally, rodent cancer models have driven preclinical oncology research. However, they do not fully recapitulate characteristics of human cancers, and their size poses challenges when evaluating tools in the interventional oncologists' armamentarium. Pig models, however, have been the gold standard for validating surgical procedures. Their size enables the study of image-guided interventions using human ultrasound (US), computed tomography (CT), and magnetic resonance (MR) imaging platforms. Furthermore, pigs have immunologic features that are similar to those of humans, which can potentially be leveraged for studying immunotherapy. Novel pig models of cancer are being developed, but additional research is required to better understand both the pig immune system and malignancy to enhance the potential for pig models in interventional oncology research. This review aims to address the main advantages and disadvantages of using a pig model for interventional oncology and outline the specific characteristics of pig models that make them more suitable for investigation of locoregional therapies.

Diversity and host interaction of the gut microbiota in specific pathogen-free pigs

Pigs are widely used as animal models in various studies related to humans. The interaction between the gut microbiota and the host has significant effects on the host's health and disease status. However, although there have been many studies investigating the pig gut microbiota, the findings have been inconsistent due to variations in rearing conditions. Interactions between the gut microbiota and host have not been fully explored in pigs. Specific pathogen-free (SPF) pigs are ideal non-primate large animals to study the interactions between the gut microbiota and the host. In this study, we performed high-throughput sequencing analysis of the gut microbiota and the gut tissue transcriptome of six SPF pigs to provide a systematic understanding of the composition, function, and spatial distribution of gut microbiota in SPF pigs. We identified significant differences in microbial diversity and functionality among different gastrointestinal tract sites. Metagenomics data analysis revealed significant differences in alpha diversity and beta diversity of microbiota in different gastrointestinal sites of SPF pigs. Additionally, transcriptomic data indicated significant differences in gene expression as well as KEGG and GO functional enrichment between the small intestine and large intestine. Furthermore, by combining microbial metagenomics and host transcriptomics analyses, specific correlations were found between gut microbiota and host genes. These included a negative correlation between the TCN1 gene and Prevotella dentalis, possibly related to bacterial metabolic pathways involving vitamin B12, and a positive correlation between the BDH1 gene and Roseburia hominis, possibly because both are involved in fatty acid metabolism. These findings lay the groundwork for further exploration of the co-evolution between the microbiota and the host, specifically in relation to nutrition, metabolism, and immunity. In conclusion, we have elucidated the diversity of the gut microbiota in SPF pigs and conducted a detailed investigation into the interactions between the gut microbiota and host gene expression. These results contribute to our understanding of the intricate dynamics between the gut microbiota and the host, offering important references for advancements in life science research, bioproduct production, and sustainable development in animal husbandry.

Revealing the mechanism of fiber promoting sow embryo implantation by altering the abundance of uterine fluid proteins: A proteomic perspective

Many studies have shown that fiber in the diet plays an important role in improving the reproductive performance of sows, but there is rarely research on the impact of fiber on early embryo implantation. This study used 4D-Label free technology to identify and analyze the effect of the fiber composition in the diet on the protein in the early pregnancy uterine fluid (UF) of sows. The results indicate that ratio of insoluble fibers to soluble fibers (ISF/SF) 4.89 can increase the concentration of progesterone (PROG) and reduce tumor necrosis factorα (TNF-α) concentration in sow UF. In addition, through 4D-Label free, we identified a total of 4248 proteins, 38 proteins abundance upregulated and 283 proteins abundance downregulated in UF. Through enrichment analysis of these differential abundance proteins (DAPs), it was found that these differential proteins are mainly related to the docking of extracellular vesicles, vesicular transport, inflammatory response, and insulin resistance. Therefore, the results of this study reveal the possible mechanism by which fiber improves the reproductive performance of sows, laying a theoretical foundation for future research on the effects of diet on reproduction. SIGNIFICANCE: This study demonstrates the importance of dietary fiber for early embryo implantation in sows. The effect of dietary ISF/SF on early embryo implantation in sows was elucidated from a proteomic perspective through 4D-Label free technology. This study not only has significant implications for improving sow reproductive efficiency, but also provides important theoretical references for studying early miscarriage and reproductive nutrition in human pregnancy.

Pig Models in Retinal Research and Retinal Disease

The pig has been used as a large animal model in biomedical research for many years and its use continues to increase because induced mutations phenocopy several inherited human diseases. In addition, they are continuous breeders, can be propagated by artificial insemination, have large litter sizes (on the order of mice), and can be genetically manipulated using all of the techniques that are currently available in mice. The pioneering work of Petters and colleagues set the stage for the use of the pig as a model of inherited retinal disease. In the last 10 years, the pig has become a model of choice where specific disease-causing mutations that are not phenocopied in rodents need to be studied and therapeutic approaches explored. The pig is not only used for retinal eye disease but also for the study of the cornea and lens. This review attempts to show how broad the use of the pig has become and how it has contributed to the assessment of treatments for eye disease. In the last 10 years, there have been several reviews that included the use of the pig in biomedical research (see body of the review) that included information about retinal disease. None directly discuss the use of the pig as an animal model for retinal diseases, including inherited diseases, where a single genetic mutation has been identified or for multifactorial diseases such as glaucoma and diabetic retinopathy. Although the pig is used to explore diseases of the cornea and lens, this review focuses on how and why the pig, as a large animal model, is useful for research in neural retinal disease and its treatment.

Momordica charantia fruit reduces plasma fructosamine whereas stems and leaves increase plasma insulin in adult mildly diabetic obese Göttingen Minipigs

BACKGROUND

Traditionally Momordica charantia (Bitter gourd) is known for its blood glucose lowering potential. This has been validated by many previous studies based on rodent models but human trials are less convincing and the physiological mechanisms underlying the bioactivity of Bitter gourd are still unclear. The present study compared the effects of whole fruit or stems-leaves from five different Bitter gourd cultivars on metabolic control in adult diabetic obese Göttingen Minipigs.

METHODS

Twenty streptozotocin-induced diabetic (D) obese Minipigs (body weight ~85 kg) were subdivided in mildly and overtly D pigs and fed 500 g of obesogenic diet per day for a period of three weeks, supplemented with 20 g dried powdered Bitter gourd or 20 g dried powdered grass as isoenergetic control in a cross-over, within-subject design.

RESULTS

Bitter gourd fruit from the cultivars "Palee" and "Good healthy" reduced plasma fructosamine concentrations in all pigs combined (from 450±48 to 423±53 and 490±50 to 404±48 μmol/L, both p<0.03, respectively) indicating improved glycemic control by 6% and 17%. These effects were statistically confirmed in mildly D pigs but not in overtly D pigs. In mildly D pigs, the other three cultivars of fruit showed consistent numerical but no significant improvements in glycemic control. The composition of Bitter gourd fruit was studied by metabolomics profiling and analysis identified three metabolites from the class of triterpenoids (Xuedanoside H, Acutoside A, Karaviloside IX) that were increased in the cultivars "Palee" (>3.9-fold) and "Good healthy" (>8.9-fold) compared to the mean of the other three cultivars. Bitter gourd stems and leaves from the cultivar "Bilai" increased plasma insulin concentrations in all pigs combined by 28% (from 53±6 to 67±9 pmol/L, p<0.03). The other two cultivars of stems and leaves showed consistent numerical but no significant increases in plasma insulin concentrations. The effects on plasma insulin concentrations were confirmed in mildly D pigs but not in overtly D pigs.

CONCLUSIONS

Fruits of Bitter gourd improve glycemic control and stems-leaves of Bitter gourd increase plasma insulin concentrations in an obese pig model for mild diabetes. The effects of Bitter gourd fruit on glycemic control seem consistent but relatively small and cultivar specific which may explain the varying results of human trials reported in the literature.

Analysis of blood composition by porcine breeding cycle

BACKGROUND

Pigs for biomedical research are administered commercial fluids made for human consumption when they receive intravenous (IV) fluid therapy. Although pigs and humans have slightly different bodily fluid compositions, the composition shift happens at the same rate as their rapid growth.

OBJECTIVE

The study aimed to analyse the composition of porcine blood according to breeding cycle using a portable blood analyser and provides data for developing customized IV fluids for pigs.

METHODS

Pigs were sorted 25, 50, 100 and 120 days after birth, and sows were classified into candidate, pregnant and farrowing groups. A blood sample was collected from the external jugular vein and analysed using the EPOC blood analysis system using haematological, biochemical and gas parameters.

RESULTS

There was no difference among pig groups by age, but hematocrit and haemoglobin amounts decreased in sows after farrowing, but their concentrations were higher as compared to pigs. Glucose gradually reduced as age increased in pigs and during pregnancy in sows.

CONCLUSION

This study provided a comprehensive analysis of porcine blood composition by breeding cycle and highlighted the importance of glucose supplementation for IV fluid therapy in pigs.

Comparative analysis of swine leukocyte antigen gene diversity in Göttingen Minipigs

Worldwide, pigs represent economically important farm animals, also representing a preferred preclinical large animal model for biomedical studies. The need for swine leukocyte antigen (SLA) typing is increasing with the expanded use of pigs in translational research, infection studies, and for veterinary vaccine design. Göttingen Minipigs (GMP) attract increasing attention as valuable model for pharmacological studies and transplantation research. This study represents a first-time assessment of the SLA gene diversity in Göttingen Minipigs in combination with a comparative metadata analysis with commercial pig lines. As Göttingen Minipigs could harbor private as well as potential novel SLA allele combinations, future research projects would benefit from the characterization of their SLA background. In 209 Göttingen Minipigs, SLA class I (SLA-1, SLA-2, SLA-3) and class II (DRB1, DQB1, DQA) genes were characterized by PCR-based low-resolution (Lr) haplotyping. Criteria and nomenclature used for SLA haplotyping were proposed by the ISAG/IUIS-VIC SLA Nomenclature Committee. Haplotypes were assigned based on the comparison with already known breed or farm-specific allele group combinations. In total, 14 SLA class I and five SLA class II haplotypes were identified in the studied cohort, to manifest in 26 SLA class I but only seven SLA class II genotypes. The most common SLA class I haplotypes Lr-24.0 (SLA-1*15XX or Blank-SLA-3*04:04-SLA-2*06:01~02) and Lr-GMP-3.0 (SLA-1*16:02-SLA-3*03:04-SLA-2*17:01) occurred at frequencies of 23.44 and 18.66%, respectively. For SLA class II, the most prevalent haplotypes Lr-0.21 (DRB1*01XX-DQB1*05XX-DQA*04XX) and Lr-0.03 (DRB1*03:02-DQB1*03:01-DQA*01XX) occurred at frequencies of 38.28 and 30.38%. The comparative metadata analysis revealed that Göttingen Minipigs only share six SLA class I and two SLA class II haplotypes with commercial pig lines. More importantly, despite the limited number of SLA class I haplotypes, the high genotype diversity being observed necessitates pre-experimental SLA background assessment of Göttingen Minipigs in regenerative medicine, allo-transplantation, and xenograft research.

Laparoscopic ovum-pick up and in vitro embryo production in gonadotropin-stimulated gilts: Preliminary results and envisioned applications

The present study was conducted to establish if laparoscopic ovum pick-up (LOPU) could be adapted to the swine species, and if the developmental competence of LOPU-sourced oocytes from peripubertal gilts could be improved by gonadotropin stimulation, by comparing with oocytes sourced from slaughtered gilts lacking hormonal stimulation. Estrus was synchronized in 34 gilts of ∼6-8 months of age by daily oral administration of 17.6 mg altrenogest for 13 days and 10 mg dinoprost IM on the last day of altrenogest. Follicular development was stimulated in all gilts with a single injection of 1250 IU eCG given 3 days before LOPU (together with the 12th dose of altrenogest). In about half of the gilts (Group eCG-hCG), 500 IU hCG were injected IM ∼72 h after eCG injection, or ∼16-18 h prior to LOPU, to initiate oocyte maturation in vivo, while the remaining animals only received eCG (Group eCG). Most gilts underwent LOPU twice alternating the gonadotropin protocol, thereby decreasing the impact of individual variation on results. Abattoir-sourced oocytes from prepubertal gilts served as Control. Following LOPU, oocytes were in vitro matured, fertilized, and cultured to the blastocyst stage following standard procedures, while oocytes collected from Group eCG-hCG gilts were considered partly matured in vivo and were matured for ∼24 h instead of ∼44 h. Embryos reaching the blastocyst stage were fixed and stained to assess quality through cell numbers. There were no significant differences in the number of follicles aspirated and cumulus-oocyte complexes (COCs) recovered between Groups eCG-hCG and eCG (22.4 and 16.9 vs. 22.6 and 17.6, P > 0.05), as well as the recovery rate (76.6 vs. 78.1, P > 0.05). Cleavage rate was not different between Group eCG-hCG, Group eCG and Control (61.1 vs. 64.4 vs. 53.4 %, P > 0.05). However, the blastocyst rate over total oocytes (32.2 vs. 36.9 vs. 11.1 %, P < 0.05), blastocyst rate over cleaved oocytes (51.8 vs. 55.1 vs. 21.2 %, P < 0.01) and the average number of cells/blastocyst (89.6 vs. 87.5 vs. 62.2, P < 0.01) were unaffected by hCG treatment in LOPU-sourced oocytes, but both LOPU groups were significantly higher than abattoir-sourced oocytes, respectively. Our results suggest LOPU may become a powerful tool for sourcing swine oocytes with higher developmental competence than abattoir-sourced oocytes and known disease status for creating swine models for human biomedical applications, as well as for accelerated genetic gain in swine breeding programs.

Efficient derivation of transgene-free porcine induced pluripotent stem cells enables in vitro modeling of species-specific developmental timing

Sus scrofa domesticus (pig) has served as a superb large mammalian model for biomedical studies because of its comparable physiology and organ size to humans. The derivation of transgene-free porcine induced pluripotent stem cells (PiPSCs) will, therefore, benefit the development of porcine-specific models for regenerative biology and its medical applications. In the past, this effort has been hampered by a lack of understanding of the signaling milieu that stabilizes the porcine pluripotent state in vitro. Here, we report that transgene-free PiPSCs can be efficiently derived from porcine fibroblasts by episomal vectors along with microRNA-302/367 using optimized protocols tailored for this species. PiPSCs can be differentiated into derivatives representing the primary germ layers in vitro and can form teratomas in immunocompromised mice. Furthermore, the transgene-free PiPSCs preserve intrinsic species-specific developmental timing in culture, known as developmental allochrony. This is demonstrated by establishing a porcine in vitro segmentation clock model that, for the first time, displays a specific periodicity at ∼3.7 h, a timescale recapitulating in vivo porcine somitogenesis. We conclude that the transgene-free PiPSCs can serve as a powerful tool for modeling development and disease and developing transplantation strategies. We also anticipate that they will provide insights into conserved and unique features on the regulations of mammalian pluripotency and developmental timing mechanisms.

Control of the growth and development of murine preantral follicles in a biomimetic ovary using a decellularized porcine scaffold

This study aimed to derive mature oocytes from murine preantral follicles cultured in a biomimetic ovary with a porcine scaffold using decellularization technology. We evaluated the DNA content and the presence of cell and extracellular matrix (ECM) components, including collagen, elastin, and glycosaminoglycans (GAGs), in decellularized (decell) porcine ovaries. The DNA content inthe decell ovarian tissues was approximately 94 % less than that in native tissues (66 ± 9.8 ng/mg vs. 1139 ± 269 ng/mg). Furthermore, the ECM component integrity was maintained in the decell ovarian tissue. The soluble collagen concentration of native ovarian tissue (native) was 195.34 ± 15.13 μg/mg (dry wt.), which was less than 878.6 ± 8.24 μg/mg for the decell ovarian tissue due to the loss of cellular mass. Hydrogels derived from decell porcine ovaries were prepared to develop an in vitro biomimetic ovary with appropriate ECM concentration (2-6 mg/mL). Scanning electron microscope (SEM) imagining revealed that the complex fiber network and porous structure were maintained in all groups treated with varying ECM concentration (2-6 mg/mL). Furthermore, rheometer analysis indicated that mechanical strength increased with ECM concentration in a dose-dependently. The preantral follicles cultured with 4 mg/mL ECM showed high rates of antral follicle (66 %) and mature oocyte (metaphase II) development (47 %). The preantral follicles cultured in a biomimetic ovary with a decell porcine scaffold showed a higher rate of antral follicle and mature oocytes than those cultured in other biomaterials such as collagen and Matrigel. In mature oocytes derived from antral follicles, meiotic spindles and nuclei were stained using a tubulin antibody and Hoechst, respectively. Two-cell embryos were developed from MII oocytes following parthenogenetic activation. Preantral follicles were cultured in a biomimetic ovary derived from the ECM of a decell porcine ovary, and embryos were generated from MII oocytes. This biomimetic ovary could contribute to restoring fertility in infertile women with reduced ovarian function, benefit mating efforts for endangered species, and maintain animals with valuable genetic traits.

An optimized prime editing system for efficient modification of the pig genome

Prime editing (PE) is a recent gene editing technology that can mediate insertions or deletions and all twelve types of base-to-base conversions. However, its low efficiency hampers the application in creating novel breeds and biomedical models, especially in pigs and other important farm animals. Here, we demonstrate that the pig genome is editable using the PE system, but the editing efficiency was quite low as expected. Therefore, we aimed to enhance PE efficiency by modulating both exogenous PE tools and endogenous pathways in porcine embryonic fibroblasts (PEFs). First, we modified the pegRNA by extending the duplex length and mutating the fourth thymine in a continuous sequence of thymine bases to cytosine, which significantly enhanced PE efficiency by improving the expression of pegRNA and targeted cleavage. Then, we targeted SAMHD1, a deoxynucleoside triphosphate triphosphohydrolase (dNTPase) that impedes the reverse transcription process in retroviruses, and found that treatment with its inhibitor, cephalosporin C zinc salt (CPC), increased PE efficiency up to 29-fold (4-fold on average), presumably by improving the reverse transcription process of Moloney murine leukemia virus reverse transcriptase (M-MLV RT) in the PE system. Moreover, PE efficiency was obviously improved by treatment with a panel of histone deacetylase inhibitors (HDACis). Among the four HDACis tested, panobinostat was the most efficient, with an efficiency up to 122-fold (7-fold on average), partly due to the considerable HDACi-mediated increase in transgene expression. In addition, the synergistic use of the three strategies further enhanced PE efficiency in PEFs. Our study provides novel approaches for optimization of the PE system and broadens the application scope of PE in agriculture and biomedicine.

Influence of general anaesthesia on circulating biomarkers of glucose metabolism in pigs

Pigs are widely used in metabolic research with procedures often requiring general anaesthesia. The aim was to investigate the effect of four different anaesthetic protocols: 1) isoflurane inhalation, 2) propofol infusion, 3) a mixture of tiletamine, zolazepam, medetomidine, ketamine and butorphanol (TZMKB)) and 4) ketamine combined with midazolam and xylazine (KMX)) on selected biomarkers during basal and glucose stimulated conditions. Eight domestic pigs were included in a cross-over design. Plasma concentrations of glucose, insulin, C-peptide, glucagon, cortisol, triglycerides, total cholesterol, aspartate amino transferase and alanine amino transferase, creatinine, urea, fructosamine, albumin, free fatty acids (FFAs) and glycerol were measured at baseline, during 2 h of anaesthesia and during 1 h of recovery. Intravenous glucose tolerance test (IVGTT, 0.5 g glucose/kg) was performed after 1 h of anaesthesia. Glucose disappearance rate and areas under the insulin, C-peptide and glucagon curves from the IVGTT were calculated. All four anaesthetic protocols affected glucose metabolism parameters significantly compared with un-anaesthetised pigs, which was particularly evident during IVGTT and for TZMKB and KMX anaesthesia. Propofol additionally influenced the plasma concentrations of triglycerides, FFAs and glycerol significantly. The remaining circulating biomarkers were largely unaffected by anaesthesia. These data underline the importance of considering the anaesthetic protocol in porcine studies of circulating metabolic biomarkers.

Establishment and validation of intravenous anesthesia with dexmedetomidine for pigs under assisted spontaneous breathing: A preclinical model of intensive care conditions

Large animal models are frequently used to investigate new medical approaches. In most cases, animals are kept under general anesthesia and mandatory mechanical ventilation during the experiments. However, in some situations assisted spontaneous breathing is essential, e.g. when simulating conditions in a modern intensive care unit. Therefore, we established an anesthesia regime with dexmedetomidine and midazolam/ketamine in porcine models of assisted spontaneous breathing. The total intravenous anesthesia was used in lung healthy pigs, in pigs with oleic acid induced acute respiratory distress syndrome and in pigs with methacholine induced bronchopulmonary obstruction. We were able to maintain stable conditions of assisted spontaneous breathing without impairment of hemodynamic, respiratory or blood gas variables in lung healthy pigs and pigs with induced acute respiratory distress syndrome for a period of five hours and in pigs with induced bronchopulmonary obstruction for three hours. Total intravenous anesthesia containing dexmedetomidine enables stable conditions of assisted spontaneous breathing in healthy pigs, in pigs with induced acute respiratory distress syndrome and in pigs induced bronchopulmonary obstruction as models of intensive care unit conditions.

Testing spatial working memory in pigs using an automated T-maze

Pigs are an important large animal model for translational clinical research but underutilized in behavioral neuroscience. This is due, in part, to a lack of rigorous neurocognitive assessments for pigs. Here, we developed a new automated T-maze for pigs that takes advantage of their natural tendency to alternate. The T-maze has obvious cross-species value having served as a foundation for cognitive theories across species. The maze (17' × 13') was constructed typically and automated with flanking corridors, guillotine doors, cameras, and reward dispensers. We ran nine pigs in (1) a simple alternation task and (2) a delayed spatial alternation task. Our assessment focused on the delayed spatial alternation task which forced pigs to wait for random delays (5, 60, 120, and 240 s) and burdened spatial working memory. We also looked at self-paced trial latencies, error types, and coordinate-based video tracking. We found pigs naturally alternated but performance declined steeply across delays (R2 = 0.84). Self-paced delays had no effect on performance suggestive of an active interference model of working memory. Positional and head direction data could differentiate subsequent turns on short but not long delays. Performance levels were stable over weeks in diverse strains and sexes, and thus provide a benchmark for future neurocognitive assessments in pigs.

Archaeome structure and function of the intestinal tract in healthy and H1N1 infected swine

Background

Methanogenic archaea represent a less investigated and likely underestimated part of the intestinal tract microbiome in swine.

Aims/Methods

This study aims to elucidate the archaeome structure and function in the porcine intestinal tract of healthy and H1N1 infected swine. We performed multi-omics analysis consisting of 16S rRNA gene profiling, metatranscriptomics and metaproteomics.

Results and discussion

We observed a significant increase from 0.48 to 4.50% of archaea in the intestinal tract microbiome along the ileum and colon, dominated by genera Methanobrevibacter and Methanosphaera. Furthermore, in feces of naïve and H1N1 infected swine, we observed significant but minor differences in the occurrence of archaeal phylotypes over the course of an infection experiment. Metatranscriptomic analysis of archaeal mRNAs revealed the major methanogenesis pathways of Methanobrevibacter and Methanosphaera to be hydrogenotrophic and methyl-reducing, respectively. Metaproteomics of archaeal peptides indicated some effects of the H1N1 infection on central metabolism of the gut archaea.

Conclusions/Take home message

Finally, this study provides the first multi-omics analysis and high-resolution insights into the structure and function of the porcine intestinal tract archaeome during a non-lethal Influenza A virus infection of the respiratory tract, demonstrating significant alterations in archaeal community composition and central metabolic functions.

Amino acid buffered hypochlorite facilitates debridement of porcine infected burn wounds

INTRODUCTION

Removal of necrotic tissue is a vital step in the treatment of full-thickness burn wounds, with surgical debridement being the most effective method. Since minor burn wounds are typically treated on an outpatient basis where surgical capabilities can be limited there is a need for alternative treatment options. In this study we aim to evaluate the use of amino acid buffered hypochlorite (AABH) as a chemical enhancement for wound debridement in a porcine infected burn wound model.

METHOD

A total of 60 full-thickness burn wounds, 3 cm in diameter, were created on four pigs using a standardized burn device. The wounds were inoculated with 107 colony-forming units (CFU) of S. aureus. The experimental groups included wounds debrided with a plastic curette, wounds debrided after pretreatment with AABH, and control wounds wiped with gauze. Wounds were treated twice per week for three weeks. Debridement, healing, and infection parameters were evaluated over time.

RESULTS

After one week, but not after two and three weeks, the curette and AABH groups had higher debrided weights compared to control (p < 0.05). Percentage of wound area adequately cleared from necrotic tissue was higher in the AABH-group compared to the curette-group and control, after one week. The earliest healing was measured in the AABH group after two weeks (5 % of wounds), which also had the most healed wounds after three weeks (55 %). In both the AABH and the curette groups, bacterial load had fallen below 105 CFU/g after two weeks. No CFU were detectable in the AABH group after three weeks. The AABH-group was also the easiest to debride.

CONCLUSION

Our results indicate that AABH facilitates wound debridement and could be a helpful addition to an effective treatment modality for removal of necrotic tissue in full-thickness burns.

Porcine Models of Spinal Cord Injury

Large animal models of spinal cord injury may be useful tools in facilitating the development of translational therapies for spinal cord injury (SCI). Porcine models of SCI are of particular interest due to significant anatomic and physiologic similarities to humans. The similar size and functional organization of the porcine spinal cord, for instance, may facilitate more accurate evaluation of axonal regeneration across long distances that more closely resemble the realities of clinical SCI. Furthermore, the porcine cardiovascular system closely resembles that of humans, including at the level of the spinal cord vascular supply. These anatomic and physiologic similarities to humans not only enable more representative SCI models with the ability to accurately evaluate the translational potential of novel therapies, especially biologics, they also facilitate the collection of physiologic data to assess response to therapy in a setting similar to those used in the clinical management of SCI. This review summarizes the current landscape of porcine spinal cord injury research, including the available models, outcome measures, and the strengths, limitations, and alternatives to porcine models. As the number of investigational SCI therapies grow, porcine SCI models provide an attractive platform for the evaluation of promising treatments prior to clinical translation.

A novel porcine model of CLN3 Batten disease recapitulates clinical phenotypes

Mouse models of CLN3 Batten disease, a rare lysosomal storage disorder with no cure, have improved our understanding of CLN3 biology and therapeutics through their ease of use and a consistent display of cellular pathology. However, the translatability of murine models is limited by disparities in anatomy, body size, life span and inconsistent subtle behavior deficits that can be difficult to detect in CLN3 mutant mouse models, thereby limiting their use in preclinical studies. Here, we present a longitudinal characterization of a novel miniswine model of CLN3 disease that recapitulates the most common human pathogenic variant, an exon 7-8 deletion (CLN3Δex7/8). Progressive pathology and neuron loss is observed in various regions of the CLN3Δex7/8 miniswine brain and retina. Additionally, mutant miniswine present with retinal degeneration and motor abnormalities, similar to deficits seen in humans diagnosed with the disease. Taken together, the CLN3Δex7/8 miniswine model shows consistent and progressive Batten disease pathology, and behavioral impairment mirroring clinical presentation, demonstrating its value in studying the role of CLN3 and safety/efficacy of novel disease-modifying therapeutics.

Transcriptomic landscape reveals germline potential of porcine skin-derived multipotent dermal fibroblast progenitors

According to estimations, approximately about 15% of couples worldwide suffer from infertility, in which individuals with azoospermia or oocyte abnormalities cannot be treated with assisted reproductive technology. The skin-derived stem cells (SDSCs) differentiation into primordial germ cell-like cells (PGCLCs) is one of the major breakthroughs in the field of stem cells intervention for infertility treatment in recent years. However, the cellular origin of SDSCs and their dynamic changes in transcription profile during differentiation into PGCLCs in vitro remain largely undissected. Here, the results of single-cell RNA sequencing indicated that porcine SDSCs are mainly derived from multipotent dermal fibroblast progenitors (MDFPs), which are regulated by growth factors (EGF/bFGF). Importantly, porcine SDSCs exhibit pluripotency for differentiating into three germ layers and can effectively differentiate into PGCLCs through complex transcriptional regulation involving histone modification. Moreover, this study also highlights that porcine SDSC-derived PGCLCs specification exhibit conservation with the human primordial germ cells lineage and that its proliferation is mediated by the MAPK signaling pathway. Our findings provide substantial novel insights into the field of regenerative medicine in which stem cells differentiate into germ cells in vitro, as well as potential therapeutic effects in individuals with azoospermia and/or defective oocytes.

High and Hyper: Fentanyl Induces Psychomotor Side-Effects in Healthy Pigs

Analgesic effects of fentanyl have been investigated using behavior. The behavioral effects of fentanyl and possible serotonergic influence are largely unknown. We therefore investigated behavioral effects of fentanyl, with or without the serotonin antagonist ketanserin, in pigs. Fourteen mixed-breed pigs, weighing 17-25 kg were included in a randomised blinded prospective, balanced three-group study. Ten pigs received first 5 and then 10 µg/kg of fentanyl intravenously. Ketanserin at 1 mg/kg or saline was given intravenously as a third injection. Four control pigs received three injections of saline. Behavior was video-recorded. The distance moved was automatically measured by commercially available software, and behaviors manually scored in retrospect. Fentanyl inhibited resting and playing, and induced different repetitive behaviors. The mean (SD) distance moved in the control group and fentanyl group was 21.3 (13.0) and 57.8 (20.8) metres respectively (p < 0.05 for pairwise comparison). A stiff gait pattern was seen after fentanyl injection for median (range) 4.2 (2.8-5.1) minutes per 10 min, which was reduced to 0 (0-4) s after ketanserin administration. Conclusion: fentanyl-induced motor and behavioral effects, and serotonergic transmission may be involved in some of them. The psychomotor side effects of fentanyl could potentially interfere with post-operative pain evaluation in pigs.

Molecular Structural Analysis of Porcine CMAH-Native Ligand Complex and High Throughput Virtual Screening to Identify Novel Inhibitors

Porcine meat is the most consumed red meat worldwide. Pigs are also vital tools in biological and medical research. However, xenoreactivity between porcine's N-glycolylneuraminic acid (Neu5Gc) and human anti-Neu5Gc antibodies poses a significant challenge. On the one hand, dietary Neu5Gc intake has been connected to particular human disorders. On the other hand, some pathogens connected to pig diseases have a preference for Neu5Gc. The Cytidine monophospho-N-acetylneuraminic acid hydroxylase (CMAH) catalyses the conversion of N-acetylneuraminic acid (Neu5Ac) to Neu5Gc. In this study, we predicted the tertiary structure of CMAH, performed molecular docking, and analysed the protein-native ligand complex. We performed a virtual screening from a drug library of 5M compounds and selected the two top inhibitors with Vina scores of -9.9 kcal/mol for inhibitor 1 and -9.4 kcal/mol for inhibitor 2. We further analysed their pharmacokinetic and pharmacophoric properties. We conducted stability analyses of the complexes with molecular dynamic simulations of 200 ns and binding free energy calculations. The overall analyses revealed the inhibitors' stable binding, which was further validated by the MMGBSA studies. In conclusion, this result may pave the way for future studies to determine how to inhibit CMAH activities. Further in vitro studies can provide in-depth insight into these compounds' therapeutic potential.

An evolutionarily conserved pacemaker role for HCN ion channels in smooth muscle

Although hyperpolarization-activated cation (HCN) ion channels are well established to underlie cardiac pacemaker activity, their role in smooth muscle organs remains controversial. HCN-expressing cells are localized to renal pelvic smooth muscle (RPSM) pacemaker tissues of the murine upper urinary tract and HCN channel conductance is required for peristalsis. To date, however, the Ih pacemaker current conducted by HCN channels has never been detected in these cells, raising questions on the identity of RPSM pacemakers. Indeed, the RPSM pacemaker mechanisms of the unique multicalyceal upper urinary tract exhibited by humans remains unknown. Here, we developed immunopanning purification protocols and demonstrate that 96% of isolated HCN+ cells exhibit Ih . Single-molecule STORM to whole-tissue imaging showed HCN+ cells express single HCN channels on their plasma membrane and integrate into the muscular syncytium. By contrast, PDGFR-α+ cells exhibiting the morphology of ICC gut pacemakers were shown to be vascular mural cells. Translational studies in the homologous human and porcine multicalyceal upper urinary tracts showed that contractions and pacemaker depolarizations originate in proximal calyceal RPSM. Critically, HCN+ cells were shown to integrate into calyceal RPSM pacemaker tissues, and HCN channel block abolished electrical pacemaker activity and peristalsis of the multicalyceal upper urinary tract. Cumulatively, these studies demonstrate that HCN ion channels play a broad, evolutionarily conserved pacemaker role in both cardiac and smooth muscle organs and have implications for channelopathies as putative aetiologies of smooth muscle disorders. KEY POINTS: Pacemakers trigger contractions of involuntary muscles. Hyperpolarization-activated cation (HCN) ion channels underpin cardiac pacemaker activity, but their role in smooth muscle organs remains controversial. Renal pelvic smooth muscle (RPSM) pacemakers trigger contractions that propel waste away from the kidney. HCN+ cells localize to murine RPSM pacemaker tissue and HCN channel conductance is required for peristalsis. The HCN (Ih ) current has never been detected in RPSM cells, raising doubt whether HCN+ cells are bona fide pacemakers. Moreover, the pacemaker mechanisms of the unique multicalyceal RPSM of higher order mammals remains unknown. In total, 97% of purified HCN+ RPSM cells exhibit Ih . HCN+ cells integrate into the RPSM musculature, and pacemaker tissue peristalsis is dependent on HCN channels. Translational studies in human and swine demonstrate HCN channels are conserved in the multicalyceal RPSM and that HCN channels underlie pacemaker activity that drives peristalsis. These studies provide insight into putative channelopathies that can underlie smooth muscle dysfunction.

A porcine model of early-onset scoliosis combined with thoracic insufficiency syndrome: Construction and transcriptome analysis

BACKGROUND

Early-onset scoliosis (EOS) is a scoliosis deformity caused by various reasons before the age of 10 years and is often combined with thoracic insufficiency syndrome (TIS) causing patients with difficulty in securing lung growth in the thoracic cage. Currently, there is a shortage of effective large animal models for evaluating EOS + TIS in therapeutic studies. Consequently, we propose to construct a porcine EOS + TIS model and evaluate its transcriptome changes by RNA sequencing.

METHODS

Piglets were constructed using unilateral posterior spine-tethering and ipsilateral rib-tethering in the EOS + TIS model, and X-ray and computed tomography (CT) were performed to assess growth changes in the spine, thoracic cage and lungs. The H&E and Masson staining was performed for pathological analysis of lung tissue. After RNA sequencing of lung tissues, data were analyzed for differential expression of mRNA, functional enrichment analysis (GO, KEGG and GSEA) and protein-protein interaction (PPI) network construction, and differential expression of hub gene was verified by RT-qPCR.

RESULTS

In the model group, growth (body weight and length) of piglets was significantly delayed; fusion of ribs occurred and cobb angle changes in the coronal and sagittal planes were significantly enlarged; total lung volume (TLV) was significantly reduced, especially at the T7-T10 level. Pathological analysis revealed that, in the model lung tissue, the alveolar wall of was poorly perfused, the alveolar space was enlarged, the number and size of alveoli were significantly reduced, and it was accompanied by collagen fiber deposition. Moreover, a total of 432 differentially expressed mRNAs (DE-mRNAs) were identified in model lung tissues, which contained 262 down-regulated and 170 up-regulated DE-mRNAs, and they were mainly involved in the regulation of immunity, inflammation, cell cycle and extracellular matrix. A PPI network containing 71 nodes and 158 edges was constructed based on all DE-mRNAs, and JUN, CCL2, EGR1, ATF3, BTG2, DUSP1 and THBS1 etc. were hub gene.

CONCLUSIONS

Overall, we constructed a porcine model that was capable of replicating the common clinical features of EOS + TIS such as rib fusion, asymmetric thoracic cage, increased cobb angle, decreased TLV, and pulmonary hypoplasia. Also, we revealed transcriptomic changes in the EOS + TIS model that may cause pulmonary hypoplasia.

Organ-on-a-chip technologies for biomedical research and drug development: A focus on the vasculature

Current biomedical models fail to replicate the complexity of human biology. Consequently, almost 90% of drug candidates fail during clinical trials after decades of research and billions of investments in drug development. Despite their physiological similarities, animal models often misrepresent human responses, and instead, trigger ethical and societal debates regarding their use. The overall aim across regulatory entities worldwide is to replace, reduce, and refine the use of animal experimentation, a concept known as the Three Rs principle. In response, researchers develop experimental alternatives to improve the biological relevance of in vitro models through interdisciplinary approaches. This article highlights the emerging organ-on-a-chip technologies, also known as microphysiological systems, with a focus on models of the vasculature. The cardiovascular system transports all necessary substances, including drugs, throughout the body while in charge of thermal regulation and communication between other organ systems. In addition, we discuss the benefits, limitations, and challenges in the widespread use of new biomedical models. Coupled with patient-derived induced pluripotent stem cells, organ-on-a-chip technologies are the future of drug discovery, development, and personalized medicine.

Cas9-mediated replacement of expanded CAG repeats in a pig model of Huntington's disease

The monogenic nature of Huntington's disease (HD) and other neurodegenerative diseases caused by the expansion of glutamine-encoding CAG repeats makes them particularly amenable to gene therapy. Here we show the feasibility of replacing expanded CAG repeats in the mutant HTT allele with a normal CAG repeat in genetically engineered pigs mimicking the selective neurodegeneration seen in patients with HD. A single intracranial or intravenous injection of adeno-associated virus encoding for Cas9, a single-guide RNA targeting the HTT gene, and donor DNA containing the normal CAG repeat led to the depletion of mutant HTT in the animals and to substantial reductions in the dysregulated expression and neurotoxicity of mutant HTT and in neurological symptoms. Our findings support the further translational development of virally delivered Cas9-based gene therapies for the treatment of genetic neurodegenerative diseases.

Skin-Based Vaccination: A Systematic Mapping Review of the Types of Vaccines and Methods Used and Immunity and Protection Elicited in Pigs

The advantages of skin-based vaccination include induction of strong immunity, dose-sparing, and ease of administration. Several technologies for skin-based immunisation in humans are being developed to maximise these key advantages. This route is more conventionally used in veterinary medicine. Skin-based vaccination of pigs is of high relevance due to their anatomical, physiological, and immunological similarities to humans, as well as being a source of zoonotic diseases and their livestock value. We conducted a systematic mapping review, focusing on vaccine-induced immunity and safety after the skin immunisation of pigs. Veterinary vaccines, specifically anti-viral vaccines, predominated in the literature. The safe and potent skin administration to pigs of adjuvanted vaccines, particularly emulsions, are frequently documented. Multiple methods of skin immunisation exist; however, there is a lack of consistent terminology and accurate descriptions of the route and device. Antibody responses, compared to other immune correlates, are most frequently reported. There is a lack of research on the underlying mechanisms of action and breadth of responses. Nevertheless, encouraging results, both in safety and immunogenicity, were observed after skin vaccination that were often comparable to or superior the intramuscular route. Further research in this area will underlie the development of enhanced skin vaccine strategies for pigs, other animals and humans.

Porcine Model of the Growing Spinal Cord-Changes in Diffusion Tensor Imaging Parameters

Diffusion tensor imaging (DTI) is an advanced magnetic resonance imaging (MRI) technique that has promising applications for the objective assessment of the microstructure of the spinal cord. This study aimed to verify the parameters obtained using DTI change during the growth process. We also wanted to identify if the DTI values change on the course of the spinal cord. The model organism was a healthy growing porcine spinal cord (19 pigs, Polish White, weight 24-120 kg, mean 48 kg, median 48 kg, age 2.5-11 months, mean 5 months, median 5.5 months). DTI parameters were measured in three weight groups: up to 29 kg (five pigs), 30-59 kg (six pigs), and from 60 kg up (eight pigs). DTI was performed with a 1.5 Tesla magnetic resonance scanner (Philips, Ingenia). Image post-processing was done using the Fiber Track package (Philips Ingenia workstation) by manually drawing the regions of interest (nine ROIs). The measurements were recorded for three sections: the cervical, thoracolumbar and lumbar segments of the spinal cord at the C4/C5, Th13/L1, and L4/L5 vertebrae levels. In each case, one segment was measured cranially and one caudally from the above-mentioned places. The values of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were obtained for each ROIs and compared. It is shown that there is a correlation between age, weight gain, and change in FA and ADC parameters. Moreover, it is noted that, with increasing weight and age, the FA parameter increases and ADC decreases, whereas the FA and ADC measurement values did not significantly change between the three sections of the spinal cord. These findings could be useful in determining the reference values for the undamaged spinal cords of animals and growing humans.

Adult porcine (Sus scrofa) derived inner ear cells: Characteristics in in-vitro cultures

There is a need for an animal model that closely parallels human cochlea gestational development. This study aims to document porcine inner ear anatomy, and in vitro porcine derived inner ear cell culture characteristics. Twenty-four temporal bone were harvested from 12 adult pigs (Sus scrofa). Six were formalin fixed and their maximal diameters were measured. The cochlea duct length was determined by the insertion length of a Nucleus 22 cochlear implant in two bones. Four formalin fixed bones were sectioned for histology. Cochlear and vestibular tissues were harvested from non-fixed bones, cultured and characterized at different passages (P). Gene and protein expression of multipotent stem/progenitor (Nestin and Sox2), inner ear hair (Myosin VIIa, Prestin) and supporting (Cytokeratin 18 and Vimentin) cell markers were determined. The porcine cochlea was a 3.5 turn spiral. There was a separate vestibular compartment. The cochlear mean maximal diameter and height was 7.99 and 3.77 mm, respectively. Sphere forming cells were identified on phase-contrast microscopy. The relative mRNA expression levels of KRT18, MYO7A and SLC26A5 were significantly positively correlated in cochlear cultures; and MYO7A and SLC26A5; SOX2 and KRT18; NES and SLC26A5 genes were positively correlated in vestibular cultures (p = .037, Spearman correlation [τ] = .900). Inner ear sensory and stem cell characteristics persist in passaged porcine inner ear cells. Further work is required to establish the usefulness of porcine inner ear cell cultures to the study of human inner ear disorders.

Somatic Cell Nuclear Transfer in Pigs

Somatic cell nuclear transfer (SCNT) has been successfully applied to clone animals of several species. Pigs are one of the main livestock species for food production and are also important for biomedical research due to their physiopathological similarities with humans. In the past 20 years, clones of several swine breeds have been produced for a variety of purposes, including biomedical and agricultural applications. In this chapter, we describe a protocol to produce cloned pigs by SCNT.

Selecting the Best Animal Model of Parkinson's Disease for Your Research Purpose: Insight from in vivo PET Imaging Studies

Parkinson's disease (PD) is a debilitating neurodegenerative multisystem disorder leading to motor and non-motor symptoms in millions of individuals. Despite intense research, there is still no cure, and early disease biomarkers are lacking. Animal models of PD have been inspired by basic elements of its pathogenesis, such as dopamine dysfunction, alpha-synuclein accumulation, neuroinflammation and disruption of protein degradation, and these have been crucial for a deeper understanding of the mechanisms of pathology, the identification of biomarkers, and evaluation of novel therapies. Imaging biomarkers are non-invasive tools to assess disease progression and response to therapies; their discovery and validation have been an active field of translational research. Here, we highlight different considerations of animal models of PD that can be applied to future research, in terms of their suitability to answer different research questions. We provide the reader with important considerations of the best choice of model to use based on the disease features of each model, including issues related to different species. In addition, positron emission tomography studies conducted in PD animal models in the last 5 years are presented. With a variety of different species, interventions and genetic information, the choice of the most appropriate model to answer research questions can be daunting, especially since no single model recapitulates all aspects of this complex disorder. Appropriate animal models in conjunction with in vivo molecular imaging tools, if selected properly, can be a powerful combination for the assessment of novel therapies and developing tools for early diagnosis.

Blastocyst complementation and interspecies chimeras in gene edited pigs

The only curative therapy for many endstage diseases is allograft organ transplantation. Due to the limited supply of donor organs, relatively few patients are recipients of a transplanted organ. Therefore, new strategies are warranted to address this unmet need. Using gene editing technologies, somatic cell nuclear transfer and human induced pluripotent stem cell technologies, interspecies chimeric organs have been pursued with promising results. In this review, we highlight the overall technical strategy, the successful early results and the hurdles that need to be addressed in order for these approaches to produce a successful organ that could be transplanted in patients with endstage diseases.

Large Animal Models for Simulating Physiology of Transfusion of Red Cell Concentrates-A Scoping Review of The Literature

Background and Objectives: Transfusion of red cell concentrates is a key component of medical therapy. To investigate the complex transfusion-associated biochemical and physiological processes as well as potential risks for human recipients, animal models are of particular importance. This scoping review summarizes existing large animal transfusion models for their ability to model the physiology associated with the storage of erythrocyte concentrates. Materials and Methods: The electronic databases PubMed, EMBASE, and Web of Science were systematically searched for original studies providing information on the intravenous application of erythrocyte concentrates in porcine, ovine, and canine animal models. Results: A total of 36 studies were included in the analysis. The majority of porcine studies evaluated hemorrhagic shock conditions. Pig models showed high physiological similarities with regard to red cell physiology during early storage. Ovine and canine studies were found to model typical aspects of human red cell storage at 42 days. Only four studies provided data on 24 h in vivo survival of red cells. Conclusions: While ovine and canine models can mimic typical human erythrocyte storage for up to 42 days, porcine models stand out for reliably simulating double-hit pathologies such as hemorrhagic shock. Large animal models remain an important area of translational research since they have an impact on testing new pharmacological or biophysical interventions to attenuate storage-related adverse effects and allow, in a controlled environment, to study background and interventions in dynamic and severe disease conditions.

Simultaneous Inhibition of Histone Deacetylases and RNA Synthesis Enables Totipotency Reprogramming in Pig SCNT Embryos

Combining somatic cell nuclear transfer (SCNT) with genome editing technologies has emerged as a powerful platform for the creation of unique swine lineages for agricultural and biomedical applications. However, successful application of this research platform is still hampered by the low efficiency of these technologies, particularly in attaining complete cell reprogramming for the production of cloned pigs. Treating SCNT embryos with histone deacetylase inhibitors (HDACis), such as Scriptaid, has been routinely used to facilitate chromatin reprogramming after nuclear transfer. While increasing histone acetylation leads to a more relaxed chromatin configuration that facilitates the access of reprogramming factors and DNA repair machinery, it may also promote the expression of genes that are unnecessary or detrimental for normal embryo development. In this study, we evaluated the impact of inhibiting both histone deacetylases and RNA synthesis on pre- and post-implantation development of pig SCNT embryos. Our findings revealed that transcription can be inhibited for up to 40 h of development in porcine embryos, produced either by activation, fertilization or SCNT, without detrimentally affecting their capacity to form a blastocyst and their average number of cells at this developmental stage. Importantly, inhibiting RNA synthesis during HDACi treatment resulted in SCNT blastocysts with a greater number of cells and more abundant transcripts for genes related to embryo genome activation on days 2, 3 and 4 of development, compared to SCNT embryos that were treated with HDACi only. In addition, concomitant inhibition of histone deacetylases and RNA synthesis promoted the full reprograming of somatic cells, as evidenced by the normal fetal and full-term development of SCNT embryos. This combined treatment may improve the efficiency of the genome-editing + SCNT platform in swine, which should be further tested by transferring more SCNT embryos and evaluating the health and growth performance of the cloned pigs.

Construction and Comprehensive Analysis of miRNAs and Target mRNAs in Longissimus dorsi Muscle of Queshan Black and Large White Pigs

A miRNA-mRNA combination analysis was performed on the longissimus dorsi muscle of adult Queshan Black and Large White pigs by RNA-seq technology to reveal the molecular mechanism affecting pork quality traits. The sequencing results showed that 39 miRNAs were differentially expressed between Queshan Black and Large White pigs, which targeted 5234 mRNAs, and 15 differentially expressed miRNAs targeted 86 differentially expressed mRNAs. The qRT-PCR results showed that miRNAs showed similar expression patterns to RNA-seq. The GO analysis indicated that differentially expressed miRNAs with differential target mRNAs were primarily involved in biological processes such as phospholipase activity, MAP-kinase scaffold activity, lipase activity, and regulation of the extent of cell growth. The KEGG analysis also revealed that such mRNAs were significantly enriched in the ECM-receptor interaction, sphingolipid metabolism, apoptosis, PI3K-Akt signaling pathway, and AMPK signaling pathway. In addition, software predictions showed that 17 (13 of which were upregulated and four were downregulated) of 39 differentially expressed miRNAs targeted 118 negatively correlated expression mRNAs. The upregulated miRNAs contained 103 negatively correlated target mRNAs, whereas the downregulated miRNAs contained 15 negatively correlated target mRNAs. The GO analysis showed that such mRNAs were primarily involved in MAP-kinase scaffold activity, myoblast development, and peptidyl-lysine methylation, and the KEGG analysis showed significant enrichment in ECM-receptor interaction and focal adhesion. The functional enrichment analysis of miRNA target genes revealed that miR-328 was screened out as a key miRNA, and preliminary functional validation was performed. Moreover, the overexpressed miR-328 could affect the expression of proliferation-related genes, such as CDK2, CDK4, CCNB1, CCND1, CCNE1, and PCNA. These results indicated that miR-328 may regulate fat deposition and affect meat quality by influencing related pathways. This study revealed that the miRNA−mRNA regulatory axis affects fat deposition and skeletal muscle development, which provides a theoretical basis for further study on the molecular mechanism of meat quality.

Refining restraint techniques for research pigs through habituation

Pigs are common research models and are strong animals that can be difficult to restrain. Improper restraint can put pigs and research personnel at risk for injury and induce stress, which can affect research outcomes. This study aimed to refine restraint techniques for research pigs using habituation and operant conditioning. Forty-four (22 males, 22 females; 4 months old, ~8.1 kg) Göttingen minipigs were randomly assigned to a control (C: no interventions) or a treatment group (T). Pigs in the T group received 3 min training sessions 3 days/week for the first 14 d after arrival. Training sessions included human socialization and habituation to a hammock sling for blood collection. Blood collection occurred on day 13 for all pigs by novel technicians. Pigs were placed in the sling, blood was collected from the radial vein, and serum cortisol levels were determined (ug/dL). Pig behavior was recorded and scored for duration of time spent struggling (s) and vocalizing (s). Novel human approach tests occurred on day 12, before blood collection, and day 14, after blood collection. Pigs were scored on latency to touch the human (s) and duration of time spent in contact with the human (s). Pig weight was taken upon arrival and on day 15. Separate linear models were fitted for response variables struggle duration in sling, serum cortisol, latency to touch human, time spent in contact with human, and body weight. Fixed effects were treatment and sex. Prior to blood collection, there was no difference in response to a novel human (P &gt; 0.05) but after blood collection, T pigs were quicker to approach (estimate: −5.352, SE: 1.72, P = 0.003) and spent more time in contact with the novel human (estimate: 3.091, SE: 1.448, P = 0.039). T pigs also had lower cortisol levels during blood collection (estimate: −2.36, SE: 0.657, P = 0.001). There was no difference in behavior while in the sling (P &gt; 0.05). The results of the study suggest that even small investments in habituation and training pigs to study procedures is beneficial in reducing stress and improving human-animal relationships, but more time would be beneficial to promote calmer behavior in the sling.