The development of swine models in drug discovery and development. Future Med Chem. 2012;4:1771-1772. [PMID: 23043472 DOI: 10.4155/fmc.12.113]

Transcriptomic Characterization of the Porcine Urinary Bladder Trigone Following Intravesical Administration of Resiniferatoxin: Insights from High-Throughput Sequencing

Resiniferatoxin (RTX), a potent capsaicin analog, is being investigated as a therapeutic agent for neurogenic conditions, particularly those affecting bladder control. However, the transcriptomic effects of RTX on the urinary bladder remain largely unexplored. This study aimed to characterize the transcriptomic changes in the porcine urinary bladder trigone region removed seven days post-treatment with intravesical RTX administration (500 nmol per animal in 60 mL of 5% aqueous solution of ethyl alcohol). High-throughput sequencing identified 126 differentially expressed genes (DEGs; 66 downregulated, 60 upregulated), 5 differentially expressed long non-coding RNAs (DELs), and 22 other RNAs, collectively involved in 175 gene ontology (GO) processes. Additionally, differential alternative splicing events (DASes) and single nucleotide variants (SNVs) were detected. RTX significantly modulated signaling pathways related to nerve growth and myelination. Changes in genes associated with synaptic plasticity and neuromodulation were observed, particularly within serotoninergic and cholinergic signaling. RTX altered the expression of immune-related genes, particularly those involved in chemokine signaling and immune regulation. Notably, altered gene expression patterns suggest a potential anti-cancer role for RTX. These findings provide new insights into RTX's therapeutic effects beyond TRPV1 receptor interactions, filling a critical gap in our understanding of its molecular impact on bladder tissue.

Effects of Endotracheal Epinephrine on Pharmacokinetics and Survival in a Swine Pediatric Cardiac Arrest Model

OBJECTIVES

The aim of this study was to compare the endotracheal tube (ET) and intravenous (IV) administration of epinephrine relative to concentration maximum, time to maximum concentration, mean concentration over time (MC), area under the curve, odds, and time to return of spontaneous circulation (ROSC) in a normovolemic pediatric cardiac arrest model.

METHODS

Male swine weighing 24-37 kg were assigned to 4 groups: ET (n = 8), IV (n = 7), cardiopulmonary resuscitation (CPR) + defibrillation (CPR + Defib) (n = 5), and CPR only (n = 3). Swine were placed arrest for 2 minutes, and then CPR was initiated for 2 minutes. Epinephrine (0.1 mg/kg) for the ET group or 0.01 mg/kg for the IV was administered every 4 minutes or until ROSC. Defibrillation started at 3 minutes and continued every 2 minutes for 30 minutes or until ROSC for all groups except the CPR-only group. Blood samples were collected over a period of 5 minutes.

RESULTS

The MC of plasma epinephrine for the IV group was significantly higher at the 30- and 60-second time points (P = 0.001). The ET group had a significantly higher MC of epinephrine at the 180- and 240-second time points (P < 0.05). The concentration maximum of plasma epinephrine was significantly lower for the ET group (195 ± 32 ng/mL) than for the IV group (428 ± 38 ng/mL) (P = 0.01). The time to maximum concentration was significantly longer for the ET group (145 ± 26 seconds) than for the IV group (42 ± 16 seconds) (P = 0.01). No significant difference existed in area under the curve between the 2 groups (P = 0.62). The odds of ROSC were 7.7 times greater for the ET versus IV group. Time to ROSC was not significantly different among the IV, ET, and CPR + Defib groups (P = 0.31).

CONCLUSIONS

Based on the results of this study, the ET route of administration should be considered a first-line intervention.

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.

Impact of intravenous fluid administration on cardiac output and oxygenation during cardiopulmonary resuscitation

BACKGROUND

The effect of intravenous fluid (IVF) administration during cardiopulmonary resuscitation (CPR) is an unexplored factor that may improve cardiac output (CO) during CPR. The aim of this study was to determine the effect of IVF administration on CO and oxygenation during CPR.

METHODS

This experimental animal study was performed in a critical care animal laboratory. Twenty-two Landrace-Yorkshire female piglets weighing 27-37 kg were anesthetized, intubated, and placed on positive pressure ventilation. Irreversible cardiac arrest was induced with bupivacaine. CPR was performed with a LUCAS 3 mechanical compression device. Pigs were randomized into IVF or no-IVF groups. Pigs in the IVF group were given 20 mL/kg of Plasma-Lyte (Baxter International, Deerfield, IL USA), infused from 15 to 35 min of CPR. CPR was maintained for 50 min with serial measurements of CO obtained using ultrasound dilution technology and partial pressure of oxygen (PaO₂).

RESULTS

A mixed-effects repeated measures analysis of variance was used to compare within-group, and between-group mean changes in CO and PaO₂ over time. CO and PaO₂ for the piglets were measured at 10-min intervals during the 50 min of CPR. CO was greater in the IVF compared with the control group at all time points during and after the infusion of the IVF. Mean PaO₂ decreased with time; however, at no time was there a significant difference in PaO₂ between the IVF and control groups.

CONCLUSIONS

Administration of IVF during CPR resulted in a significant increase in CO during CPR both during and after the IVF infusion. There was no statistically significant decrease in PaO₂ between the IVF and control groups.

Molecular Influence of Resiniferatoxin on the Urinary Bladder Wall Based on Differential Gene Expression Profiling

Resiniferatoxin (RTX) is a potent capsaicin analog used as a drug for experimental therapy to treat neurogenic disorders associated with enhanced nociceptive transmission, including lower urinary tract symptoms. The present study, for the first time, investigated the transcriptomic profile of control and RTX-treated porcine urinary bladder walls. We applied multistep bioinformatics and discovered 129 differentially expressed genes (DEGs): 54 upregulated and 75 downregulated. Metabolic pathways analysis revealed five significant Kyoto Encyclopedia of Genes and Genomes (KEGG) items ('folate biosynthesis', 'metabolic pathways', 'sulfur relay system', 'sulfur metabolism' and 'serotonergic synapse') that were altered after RTX intravesical administration. A thorough analysis of the detected DEGs indicated that RTX treatment influenced the signaling pathways regulating nerve growth, myelination, axon specification, and elongation. Many of the revealed DEGs are involved in the nerve degeneration process; however, some of them were implicated in the initiation of neuroprotective mechanisms. Interestingly, RTX intravesical installation was followed by changes in the expression of genes involved in synaptic plasticity and neuromodulation, including 5-HT, H2S, glutamate, and GABA transmission. The obtained results suggest that the toxin may exert a therapeutic, antinociceptive effect not only by acting on TRPV1 receptors.

A humanized minipig model for the toxicological testing of therapeutic recombinant antibodies

The safety of most human recombinant proteins can be evaluated in transgenic mice tolerant to specific human proteins. However, owing to insufficient genetic diversity and to fundamental differences in immune mechanisms, small-animal models of human diseases are often unsuitable for immunogenicity testing and for predicting adverse outcomes in human patients. Most human therapeutic antibodies trigger xenogeneic responses in wild-type animals and thus rapid clearance of the drugs, which makes in vivo toxicological testing of human antibodies challenging. Here we report the generation of Göttingen minipigs carrying a mini-repertoire of human genes for the immunoglobulin heavy chains γ1 and γ4 and the immunoglobulin light chain κ. In line with observations in human patients, the genetically modified minipigs tolerated the clinically non-immunogenic IgG1κ-isotype monoclonal antibodies daratumumab and bevacizumab, and elicited antibodies against the checkpoint inhibitor atezolizumab and the engineered interleukin cergutuzumab amunaleukin. The humanized minipigs can facilitate the safety and efficacy testing of therapeutic antibodies.

Exposure of intestinal explants to NX, but not to DON, enriches the secretome in mitochondrial proteins

NX is a type A trichothecene produced by Fusarium graminearum with limited information on its toxicity. NX is structurally similar to deoxynivalenol (DON), only differing by the lacking keto group at C8. Because of the structural similarity of the two toxins as well as their potential co-occurrence in food and feed, it is of interest to determine the toxicity of this new compound. In this study, we compared the protein composition of the extracellular media of pig intestinal explants (secretome) exposed to 10 µM of DON or NX for 4 h compared with controls. The combination of two complementary quantitative proteomic approaches (a gel-based and a gel-free approach) identified 18 and 23 differentially abundant proteins (DAPs) for DON and NX, respectively, compared to controls. Functional analysis suggested that, whereas DON toxicity was associated with decreased cell viability and cell destruction, NX toxicity was associated with an enrichment of mitochondrial proteins in the secretome. The presence of these proteins may be associated with the already known ability of NX to induce an intestinal inflammation. Overall, our results indicated that DON- and NX-induced changes in the extracellular proteome of intestinal explants are different. The increased leakage/secretion of mitochondrial proteins by NX may be a feature of NX toxicity.

FSHD Therapeutic Strategies: What Will It Take to Get to Clinic?

Facioscapulohumeral muscular dystrophy (FSHD) is arguably one of the most challenging genetic diseases to understand and treat. The disease is caused by epigenetic dysregulation of a macrosatellite repeat, either by contraction of the repeat or by mutations in silencing proteins. Both cases lead to chromatin relaxation and, in the context of a permissive allele, pathogenic misexpression of DUX4 in skeletal muscle. The complex nature of the locus and the fact that FSHD is a toxic, gain-of-function disease present unique challenges for the design of therapeutic strategies. There are three major DUX4-targeting avenues of therapy for FSHD: small molecules, oligonucleotide therapeutics, and CRISPR-based approaches. Here, we evaluate the preclinical progress of each avenue, and discuss efforts being made to overcome major hurdles to translation.

Tibial Intraosseous Administration of Epinephrine Is Effective in Restoring Return of Spontaneous Circulation in a Pediatric Normovolemic But Not Hypovolemic Cardiac Arrest Model

OBJECTIVE

We compared the efficacy of tibial intraosseous (TIO) administration of epinephrine in a pediatric normovolemic versus hypovolemic cardiac arrest model to determine the incidence of return of spontaneous circulation (ROSC) and plasma epinephrine concentrations over time.

METHODS

This experimental study evaluated the pharmacokinetics of epinephrine and/or incidence of ROSC after TIO administration in either a normovolemic or hypovolemic pediatric swine model.

RESULTS

All subjects in the TIO normovolemia cardiac arrest group experienced ROSC after TIO administration of epinephrine. In contrast, subjects experiencing hypovolemia and cardiac arrest were significantly less likely to experience ROSC when epinephrine was administered TIO versus intravenous (TIO hypovolemia: 14% [1/7] vs IV hypovolemia: 71% [5/7]; P = 0.031). The TIO hypovolemia group exhibited significantly lower plasma epinephrine concentrations versus IV hypovolemia at 60, 90, 120, and 150 seconds (P < 0.05). Although the maximum concentration of plasma epinephrine was similar, the TIO hypovolemia group exhibited significantly slower time to maximum concentration times versus TIO normovolemia subjects (P = 0.004).

CONCLUSIONS

Tibial intraosseous administration of epinephrine reliably facilitated ROSC among normovolemic cardiac arrest pediatric patients, which is consistent with published reports. However, TIO administration of epinephrine was ineffective in restoring ROSC among subjects experiencing hypovolemia and cardiac arrest. Tibial intraosseous-administered epinephrine during hypovolemia and cardiac arrest may have resulted in a potential sequestration of epinephrine in the tibia. Central or peripheral intravascular access attempts should not be abandoned after successful TIO placement in the resuscitation of patients experiencing concurrent hypovolemia and cardiac arrest.

Effect of Chemically-Induced Diabetes Mellitus on Phenotypic Variability of the Enteric Neurons in the Descending Colon in the Pig

Gastrointestinal neuropathy in diabetes is one of numerous diseases resulting in abnormal functioning of the gastrointestinal tract (GIT), and it may affect any section of the GIT, including the descending colon. In the gastrointestinal system, the neurons are arranged in an interconnecting network defined as the enteric nervous system (ENS) which includes the myenteric plexus and the submucosal plexuses: inner and outer. Regular functioning of the ENS is determined by normal synthesis of the neurotransmitters and neuromodulators. This paper demonstrates the effect of hyperglycaemia on the number of enteric neurons which are immunoreactive to: neural isoform of nitric oxide synthase (nNOS), vasoactive intestinal peptide (VIP), galanin (GAL), calcitonin generelated peptide (CGRP) and cocaine amphetamine-regulated transcript (CART) in the porcine descending colon. It was demonstrated that there was a statistically significant increase in the number of neurons within the myenteric plexus immunoreactive to all investigated substances. In the outer submucosal plexus, the CART-positive neurons were the only ones not to change, whereas no changes were recorded for nNOS or CART in the inner submucosal plexus. This study is the first study to discuss quantitative changes in the neurons immunoreactive to nNOS, VIP, GAL, CGRP and CART in the descending colon in diabetic pigs.

Somatostatin immunoreactivity within the urinary bladder nerve fibers and paracervical ganglion urinary bladder projecting neurons in the female pig

The study was designed to examine the distribution and chemical coding of somatostatin-immunoreactive (SOM-IR) nerve fibers supplying the urinary bladder wall and to establish the distribution and immunohistochemical characteristics of the subpopulation of paracervical ganglion (PCG) SOM-IR neurons projecting to this organ in female pigs. The PCG-urinary bladder projecting neurons (PCG-UBPN) were visualized with retrograde neuronal tracer Fast Blue (FB). Double-labeling immunohistochemistry performed on cryostat sections from the urinary bladder wall revealed that the greatest density of SOM-IR nerve fibers was found in the muscle layer and around blood vessels, a moderate number of these nerve terminals supplied the submucosa and only single SOM-IR axons were encountered beneath the urothelium. In all the investigated sections the vast majority of SOM-IR nerve fibers were immunopositive to vesicular acetylcholine transporter (VAChT) and many SOM-IR axons contained immunoreactivity to neuropeptide Y (NPY). Approximately 65 % of FB-positive (FB+) PCG-UBPN were immunoreactive to SOM. Moreover, PCG FB+/SOM + nerve cells were simultaneously immunoreactive to choline acetyltransferase (ChAT; 64.6 ± 0.6 %), NPY (59.7 ± 1.2 %), neuronal nitric oxide synthase (nNOS; 46.1 ± 0.7 %), vasoactive intestinal polypeptide (VIP; 29.9 ± 2.2 %), Leu⁵-enkephalin (L-ENK; 19.5 ± 6.3 %), dopamine β-hydroxylase (DβH; 14.9 ± 1.9 %) or pituitary adenylate cyclase-activating polypeptide (PACAP; 14.8 ± 2.4 %). The present study reveals the extensive expression of SOM in both the nerve fibres supplying the porcine urinary bladder wall and the PCG neurons projecting to this organ, indicating an important regulatory role of SOM in the control of the urinary bladder function.

Cocaine and Amphetamine Regulated Transcript (CART) Expression Changes in the Stomach Wall Affected by Experimentally Induced Gastric Ulcerations

Cocaine- and amphetamine-regulated transcript (CART) is a peptide suggested to play a role in gastrointestinal tract tissue reaction to pathology. Gastric ulceration is a common disorder affecting huge number of people, and additionally, it contributes to the loss of pig livestock production. Importantly, ulceration as a focal disruption affecting deeper layers of the stomach wall differs from other gastrointestinal pathologies and should be studied individually. The pig’s gastrointestinal tract, due to its many similarities to the human counterpart, provides a valuable experimental model for studying digestive system pathologies. To date, the role of CART in gastric ulceration and the expression of the gene encoding CART in porcine gastrointestinal tube are completely unknown. Therefore, we aimed to verify the changes in the CART expression by Q-PCR (gene encoding CART in the tissue) and double immunofluorescence staining combined with confocal microscopy (CART immunofluorescence in enteric nervous system) in the porcine stomach tissues adjacent to gastric ulcerations. Surprisingly, we found that gastric ulcer caused a significant decrease in the expression of CART-encoding gene and huge reduction in the percentage of CART-immunofluorescent myenteric perikarya and neuronal fibers located within the circular muscle layer. Our results indicate a unique CART-dependent gastric response to ulcer disease.

Evaluation of aqueous dimethyl trisulfide as an antidote to a highly lethal cyanide poisoning in a large swine model

BACKGROUND

Cyanide is a rapid acting, lethal, metabolic poison and remains a significant threat. Current FDA-approved antidotes are not amenable or efficient enough for a mass casualty incident.

OBJECTIVE

The objective of this study is to evaluate short and long-term efficacy of intramuscular aqueous dimethyl trisulfide (DMTS) on survival and clinical outcomes in a swine model of cyanide exposure.

METHODS

Anesthetized swine were instrumented and acclimated until breathing spontaneously. Potassium cyanide infusion was initiated and continued until 5 min after the onset of apnea. Subsequently, animals were treated with intramuscular DMTS (n = 11) or saline control (n = 10). Laboratory values and DMTS blood concentrations were assessed at various time points and physiological parameters were monitored continuously until the end of the experiment unless death occurred. A subset of animals treated with DMTS (n = 5) were survived for 7 days to evaluate muscle integrity by repeat biopsy and neurobehavioral outcomes.

RESULTS

Physiological parameters and time to apnea were similar in both groups at baseline and at time of treatment. Survival in the DMTS-treated group was 90% and 30% in saline controls (p = 0.0034). DMTS-treated animals returned to breathing at 12.0 ± 10.4 min (mean ± SD) compared to 22.9 ± 7.0 min (mean ± SD) in the 3 surviving controls. Blood collected prior to euthanasia showed improved blood lactate concentrations in the DMTS treatment group; 5.47 ± 2.65 mmol/L vs. 9.39 ± 4.51 mmol/L (mean ± SD) in controls (p = 0.0310). Low concentrations of DMTS were detected in the blood, gradually increasing over time with no elimination phase observed. There was no mortality, histological evidence of muscle trauma, or observed adverse neurobehavioral outcomes, in DMTS-treated animals survived to 7 days.

CONCLUSION

Intramuscular administration of aqueous DMTS improves survival following cyanide poisoning with no observed long-term effects on muscle integrity at the injection site or adverse neurobehavioral outcomes.

Intramuscular cobinamide as an antidote to methyl mercaptan poisoning

BACKGROUND

Methyl mercaptan occurs naturally in the environment and is found in a variety of occupational settings, including the oil, paper, plastics, and pesticides industries. It is a toxic gas and deaths from methyl mercaptan exposure have occurred. The Department of Homeland Security considers it a high threat chemical agent that could be used by terrorists. Unfortunately, no specific treatment exists for methyl mercaptan poisoning.

METHODS

We conducted a randomized trial in 12 swine comparing no treatment to intramuscular injection of the vitamin B₁₂ analog cobinamide (2.0 mL, 12.5 mg/kg) following acute inhalation of methyl mercaptan gas. Physiological and laboratory parameters were similar in the control and cobinamide-treated groups at baseline and at the time of treatment.

RESULTS

All six cobinamide-treated animals survived, whereas only one of six control animals lived (17% survival) (p = 0.0043). The cobinamide-treated animals returned to a normal breathing pattern by 3.8 ± 1.1 min after treatment (mean ± SD), while all but one animal in the control group had intermittent gasping, never regaining a normal breathing pattern. Blood pressure and arterial oxygen saturation returned to baseline values within 15 minutes of cobinamide-treatment. Plasma lactate concentration increased progressively until death (10.93 ± 6.02 mmol [mean ± SD]) in control animals, and decreased toward baseline (3.79 ± 2.93 mmol [mean ± SD]) by the end of the experiment in cobinamide-treated animals.

CONCLUSION

We conclude that intramuscular administration of cobinamide improves survival and clinical outcomes in a large animal model of acute, high dose methyl mercaptan poisoning.

Inferior vagal ganglion galaninergic response to gastric ulcers

Galanin is a neuropeptide widely expressed in central and peripheral nerves and is known to be engaged in neuronal responses to pathological changes. Stomach ulcerations are one of the most common gastrointestinal disorders. Impaired stomach function in peptic ulcer disease suggests changes in autonomic nerve reflexes controlled by the inferior vagal ganglion, resulting in stomach dysfunction. In this paper, changes in the galaninergic response of inferior vagal neurons to gastric ulceration in a pig model of the disease were analyzed based on the authors' previous studies. The study was performed on 24 animals (12 control and 12 experimental). Gastric ulcers were induced by submucosal injections of 40% acetic acid solution into stomach submucosa and bilateral inferior vagal ganglia were collected one week afterwards. The number of galanin-immunoreactive perikarya in each ganglion was counted to determine fold-changes between both groups of animals and Q-PCR was applied to verify the changes in relative expression level of mRNA encoding both galanin and its receptor subtypes: GalR1, GalR2, GalR3. The results revealed a 2.72-fold increase in the number of galanin-immunoreactive perikarya compared with the controls. Q-PCR revealed that all studied genes were expressed in examined ganglia in both groups of animals. Statistical analysis revealed a 4.63-fold increase in galanin and a 1.45-fold increase in GalR3 mRNA as compared with the controls. No differences were observed between the groups for GalR1 or GalR2. The current study confirmed changes in the galaninergic inferior vagal ganglion response to stomach ulcerations and demonstrated, for the first time, the expression of mRNA encoding all galanin receptor subtypes in the porcine inferior vagal ganglia.

Human Clinical Relevance of the Porcine Model of Pseudoallergic Infusion Reactions

Pigs provide a highly sensitive animal model for pseudoallergic infusion reactions, which are mild-to-severe hypersensitivity reactions (HSRs) that arise following intravenous administration of certain nanoparticulate drugs (nanomedicines) and other macromolecular structures. This model has been used in research for three decades and was also proposed by regulatory bodies for preclinical assessment of the risk of HSRs in the clinical stages of nano-drug development. However, there are views challenging the human relevance of the model and its utility in preclinical safety evaluation of nanomedicines. The argument challenging the model refers to the “global response” of pulmonary intravascular macrophages (PIM cells) in the lung of pigs, preventing the distinction of reactogenic from non-reactogenic particles, therefore overestimating the risk of HSRs relative to its occurrence in the normal human population. The goal of this review is to present the large body of experimental and clinical evidence negating the “global response” claim, while also showing the concordance of symptoms caused by different reactogenic nanoparticles in pigs and hypersensitive man. Contrary to the model’s demotion, we propose that the above features, together with the high reproducibility of quantifiable physiological endpoints, validate the porcine “complement activation-related pseudoallergy” (CARPA) model for safety evaluations. However, it needs to be kept in mind that the model is a disease model in the context of hypersensitivity to certain nanomedicines. Rather than toxicity screening, its main purpose is specific identification of HSR hazard, also enabling studies on the mechanism and mitigation of potentially serious HSRs.

Intramuscular aminotetrazole cobinamide as a treatment for inhaled hydrogen sulfide poisoning in a large swine model

Hydrogen sulfide (H₂ S), a high-threat chemical agent, occurs naturally in a variety of settings. Despite multiple incidents of exposures and deaths, no FDA-approved antidote exists. A rapid-acting, easy to administer antidote is needed. We conducted a randomized control trial in swine comparing intramuscular administration of aminotetrazole cobinamide (2.9 mL, 18 mg/kg) to no treatment following inhalation of H₂ S gas. We found that aminotetrazole cobinamide administered 2 min after the onset of respiratory depression-defined as a tidal volume of less than 3 mL/kg for 2 consecutive minutes-yielded 100% survival, while all control animals died. Respiratory depression resolved in the treatment group within 3.6 ± 1.5 min (mean ± SD) of cobinamide administration, whereas control animals had intermittent gasping until death. Blood pressure and arterial oxygen saturation (SO₂ ) returned to baseline values within 5 and 10 min, respectively, of cobinamide treatment, and plasma lactate concentration decreased to less than 50% of the highest value by the end of the experiment. In control animals, plasma lactate rose continuously until death. We conclude that intramuscular aminotetrazole cobinamide is effective in a large animal, inhalational model of acute, severe H₂ S poisoning.

Effects of Streptozotocin-Induced Diabetes on the Pineal Gland in the Domestic Pig

Several observations from experiments in rodents and human patients suggest that diabetes affects pineal gland function, including melatonin secretion; however, the accumulated data are not consistent. The aim of the present study was to determine the effects of streptozotocin-induced diabetes on the pineal gland in the domestic pig, a species widely used as a model in various biomedical studies. The study was performed on 10 juvenile pigs, which were divided into two groups: control and diabetic. Diabetes was evoked by administration of streptozotocin (150 mg/kg of body weight). After six weeks, the animals were euthanized between 12.00 and 14.00, and the pineal glands were removed and divided into two equal parts, which were used for biochemical analyses and for preparation of explants for the superfusion culture. The pineal contents (per 100 μg protein) of serotonin, 5-hydroxyindole acetic acid, 5-hydroxytryptophol, 5-methoxyindole acetic acid, 5-methoxytryptophol, and 5-methoxytryptamine were significantly lower in diabetic pigs than in control pigs. In contrast, the level of N-acetylserotonin was significantly higher in diabetic animals. No significant differences were found in the level of melatonin between control and experimental pigs. The amounts of 3,4-dihydroxyphenylalanine, dopamine, norepinephrine, and 3,4-dihydroxyphenylacetic acid were significantly lower in the pineal glands of diabetic animals. The level of vanillylmandelic acid was higher in diabetic pigs. No differences were observed in the level of basal and NE-stimulated release of N-acetylserotonin or melatonin between the pineal explants prepared from control and experimental animals. In vitro treatment with insulin was ineffective. In conclusion, streptozotocin-induced diabetes affects both indole metabolism and adrenergic neurotransmission in the pig pineal gland.

Characterization of a Swine (Sus scrofa) Model of Oral Potassium Cyanide Intoxication

Cyanide is a readily available and potentially lethal substance. Oral exposure can result in larger doses, compared with other routes. Currently, there are no antidotes specific for use in the treatment of oral cyanide poisoning, and studies cannot be done in humans. We report on a new large animal model of oral cyanide toxicity to evaluate potential antidotes. Six female swine (Sus scrofa; weight, 45 to 55 kg) were anesthetized, intubated, and instrumented. Animals received a KCN bolus of either 5 or 8 mg/kg delivered via orogastric tube. Time to apnea was recorded; parameters monitored included heart rate, respiratory rate, blood pressure, pulse oximetry, end-tidal CO2, arterial blood gasses, and lactate concentrations. The Welch t test was used to calculate confidence intervals, mean, and standard deviation, and a Kaplan-Meier survival curve was used to compare survival between the 2 groups. At baseline, all animals in both groups were similar. Animals in the 5-mg/kg group had a more rapid time to apnea (5.1 ± 2.1 min), longer time to death (48.5 ± 38.1 min), and a greater rate of survival than the 8-mg/kg group (apnea, 10.6 ± 10.7 min; death, 26.1 ± 5.8 min). All animals displayed signs of toxicity (acidemia, hyperlactatemia, hypotension, apnea). We here report a large animal (swine) model of oral cyanide poisoning with dose-dependent effects in regard to time to death and survival rate. This model likely will be valuable for the development of medical countermeasures for oral cyanide poisoning.

Gastric ulcer induced changes in substance P and Nk1, Nk2, Nk3 receptors expression in different stomach localizations with regard to intrinsic neuronal system

Gastric ulceration, a focal tissue damage accompanied by inflammation, can influence other parts of the stomach. Substance P and its receptors are strongly involved in regulation of gastrointestinal motility, secretion and inflammation. The enteric nervous system is one of the regulators of gastrointestinal functioning and contributes to tissue response to the pathology. The pig, an omnivorous animal, is a valuable species for gastrointestinal experiments. Thus, the objective of the study was to verify whether the antral ulceration induces changes in the expression of substance P and tachykinin receptors in the neighboring (antrum) and distanced (corpus, pylorus) porcine gastric tissues and therein localized myenteric and submucosal perikarya as well as in the intrinsic descending neurons supplying pyloric sphincter. The experiment was performed on healthy pigs and pigs with experimentally induced gastric ulcers. Stomach samples from the corpus, antrum (adjacent to the ulcer in experimental pigs) and pylorus were analyzed by: (1) double immunofluorescence for changes in the number of SP-positive myenteric and submucosal neurons (2) Real-Time PCR for changes in expression of mRNA encoding SP and Nk1, Nk2, Nk3 receptors. Additionally, gastric descending neurons supplying pyloric sphincter were immunostained for SP. In experimental animals, only the number of SP-positive myenteric perikarya significantly increased in all stomach localizations studied. Q-PCR revealed increased expression for: SP, Nk1, Nk3 in the corpus; Nk2 and Nk3 in the pylorus; In the antrum, expression of Nk3 was increased but Nk2-decreased. Antral ulcers induced significant changes in the expression of SP and tachykinin receptors in the wide stomach area indicating sophisticated tissue reaction.

Galaninergic intramural nerve and tissue reaction to antral ulcerations

BACKGROUND

Well-developed galaninergic gastric intramural nerve system is known to regulate multiple stomach functions in physiological and pathological conditions. Stomach ulcer, a disorder commonly occurring in humans and animals, is accompanied by inflammatory reaction. Inflammation can cause intramural neurons to change their neurochemical profile. Galanin and its receptors are involved in inflammation of many organs, however, their direct participation in stomach reaction to ulcer is not known. Therefore, the aim of the study was to investigate adaptive changes in the chemical coding of galaninergic intramural neurons and mRNA expression encoding Gal, GalR1, GalR2, GalR3 receptors in the region of the porcine stomach directly adjacent to the ulcer location.

METHODS

The experiment was performed on 24 pigs, divided into control and experimental groups. In 12 experimental animals, stomach antrum ulcers were experimentally induced by submucosal injection of acetic acid solution. Stomach wall directly adjacent to the ulcer was examined by: (1) double immunohistochemistry-to verify the changes in the number of galaninergic neurons (submucosal, myenteric) and fibers; (2) real-time PCR to verify changes in mRNA expression encoding galanin, GalR1, GalR2, GalR3 receptors.

KEY RESULTS

In the experimental animals, the number of Gal-immunoreactive submucosal perikarya was increased, while the number of galaninergic myenteric neurons and fibers (in all the stomach wall layers) remained unchanged. The expression of mRNA encoding all galanin receptors was increased.

CONCLUSIONS & INTERFERENCES

The results obtained unveiled the participation of galanin and galanin receptors in the stomach tissue response to antral ulcerations.

Challenges and Opportunities for the Subcutaneous Delivery of Therapeutic Proteins

Biotherapeutics is a rapidly growing drug class, and over 200 biotherapeutics have already obtained approval, with about 50 of these being approved in 2015 and 2016 alone. Several hundred protein therapeutic products are still in the pipeline, including interesting new approaches to treatment. Owing to patients' convenience of at home administration and reduced number of hospital visits as well as the reduction in treatment costs, subcutaneous (SC) administration of biologics is of increasing interest. Although several avenues for treatment using biotherapeutics are being explored, there is still a sufficient gap in knowledge regarding the interplay of formulation conditions, immunogenicity, and pharmacokinetics (PK) of the absorption of these compounds when they are given SC. This review seeks to highlight the major concerns and important factors governing this route of administration and suggest a holistic approach for effective SC delivery.

Changes in expression of inhibitory substances in the intramural neurons of the stomach following streptozotocin- induced diabetes in the pig

AIM

Influence of chronic hyperglycemia on chemical coding of enteric neurons in stomach using pig as a model for human diabetic complications.

METHODS

Ten pigs were divided into two groups: diabetic (D group, n = 5) and control (C group, n = 5). Pigs constituting the experimental group were given streptozotocin (150 mg/kg). Animals were euthanized six weeks after the induction of diabetes. The samples of stomach were collected from animals of both groups. The cryostat sections were processed for double immunofluorescence staining using primary antisera directed towards pan-neuronal marker (Hu C/D) proteins and/or neuronal isoform of nitric oxide synthase (nNOS), vasoactive intestinal peptide (VIP) and galanin (GAL).

RESULTS

In the control group in the myenteric ganglia (MG) of the corpus we have noted 22.28% ± 1.19% of nNOS positive neurons, while in diabetic group we have found 40.74% ± 2.22% of nNOS immunoreactive perikarya (increase by 82.85 %). In turn in the pylorus we have observed 15.91% ± 0.58% nNOS containing neurons in control animals and 35.38% ± 1.54% in the diabetes group (increase by 122.37%). In the MG of the antrum and submucosal ganglion (SG) in the corpus hyperglycemia did not cause statistically significant changes. With regard to VIP-positive cell bodies in the antrum MG in the control animals we have noted 18.38 ± 1.39% and 40.74% ± 1.77% in the experimental group (increase by 121.65%). While in the corpus we have observed 23.20% ± 0.23% in the control and 30.93% ± 0.86% in the diabetes group (increase by 33.31%). In turn in the pylorus VIP positive cells bodies constituted 23.64% ± 1.56% in the control group and 31.20% ± 1.10% in the experimental group (increase by 31.97%). In the submucosal ganglion in the corpus we have noted 43.61% ± 1.06% in the control animals and 37.00% ± 1.77% in the experimental group (decrease by 15.15%). Expression of GAL-positive perikarya showed statistically significant changes only in the MG of the antrum and pylorus. In the antrum GAL positive perykarya constituted 26.53% ± 1.52% in the control and 36.67% ± 1.02% in the experimental animals (increase by 38.22%). While in the pylorus GAL positive neurons in the control group constituted 16.32% ± 0.92% and 17.99% ± 0.38% in the experimental animals (increase by 10.23%).

CONCLUSION

Our results support the hypothesis that in the course of diabetes, long term episodes of high glucose serum level may influence the chemical phenotyping of enteric neurons.

Deleterious effects of tributyltin on porcine vascular stem cells physiology

The vascular functional and structural integrity is essential for the maintenance of the whole organism and it has been demonstrated that different types of vascular progenitor cells resident in the vessel wall play an important role in this process. The purpose of the present research was to observe the effect of tributyltin (TBT), a risk factor for vascular disorders, on porcine Aortic Vascular Precursor Cells (pAVPCs) in term of cytotoxicity, gene expression profile, functionality and differentiation potential. We have demonstrated that pAVPCs morphology deeply changed following TBT treatment. After 48h a cytotoxic effect has been detected and Annexin binding assay demonstrated that TBT induced apoptosis. The transcriptional profile of characteristic pericyte markers has been altered: TBT 10nM substantially induced alpha-SMA, while, TBT 500nM determined a significant reduction of all pericyte markers. IL-6 protein detected in the medium of pAVPCs treated with TBT at both doses studied and with a dose response. TBT has interfered with normal pAVPC functionality preventing their ability to support a capillary-like network. In addition TBT has determined an increase of pAVPC adipogenic differentiation. In conclusion in the present paper we have demonstrated that TBT alters the vascular stem cells in terms of structure, functionality and differentiating capability, therefore effects of TBT in blood should be deeply explored to understand the potential vascular risk associated with the alteration of vascular stem cell physiology.

Miniature Swine for Preclinical Modeling of Complexities of Human Disease for Translational Scientific Discovery and Accelerated Development of Therapies and Medical Devices

Noncommunicable diseases, including cardiovascular disease, diabetes, chronic respiratory disease, and cancer, are the leading cause of death in the world. The cost, both monetary and time, of developing therapies to prevent, treat, or manage these diseases has become unsustainable. A contributing factor is inefficient and ineffective preclinical research, in which the animal models utilized do not replicate the complex physiology that influences disease. An ideal preclinical animal model is one that responds similarly to intrinsic and extrinsic influences, providing high translatability and concordance of preclinical findings to humans. The overwhelming genetic, anatomical, physiological, and pathophysiological similarities to humans make miniature swine an ideal model for preclinical studies of human disease. Additionally, recent development of precision gene-editing tools for creation of novel genetic swine models allows the modeling of highly complex pathophysiology and comorbidities. As such, the utilization of swine models in early research allows for the evaluation of novel drug and technology efficacy while encouraging redesign and refinement before committing to clinical testing. This review highlights the appropriateness of the miniature swine for modeling complex physiologic systems, presenting it as a highly translational preclinical platform to validate efficacy and safety of therapies and devices.

The influence of intravesical administration of resiniferatoxin (RTX) on the chemical coding of sympathetic chain ganglia (SChG) neurons supplying the porcine urinary bladder

Resiniferatoxin (RTX) is used as an experimental drug in therapy of neurogenic urinary bladder disorders. The present study investigated the chemical coding of sympathetic chain ganglia (SChG) neurons supplying porcine urinary bladder after intravesical RTX instillation. The SChG neurons were visualized with retrograde tracing method and their chemical profile was disclosed with double-labeling immunohistochemistry using antibodies against dopamine β-hydroxylase (DβH; marker of noradrenergic neurons), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), somatostatin (SOM), galanin, Leu(5)-enkephalin and neuronal nitric oxide synthase (nNOS). It was found that in both the control (n = 5) and RTX-treated pigs (n = 5), the vast majority (90.4 ± 2.8 and 89.7 ± 2.3%, respectively) of FB-positive (FB+) nerve cells were DβH+. RTX instillation caused a decrease in the number of FB+/DβH+ neurons immunopositive to NPY (71.1 ± 12.1 vs 43.2 ± 6.7%), VIP (21.3 ± 10.7 vs 5.3 ± 4.3%) or SOM (16.5 ± 4.6 vs 2.3 ± 2.6%) and a distinct increase in the number of FB+/DβH+ neurons immunoreactive to nNOS (0.8 ± 1 vs 5.3 ± 1.9 %). The present study for the first time has provided some information that therapeutic effects of RTX on the mammalian urinary bladder can be partly mediated by SChG neurons.

The Influence of Antral Ulcers on Intramural Gastric Nerve Projections Supplying the Pyloric Sphincter in the Pig (Sus scrofa domestica)-Neuronal Tracing Studies

Background

Gastric ulcerations in the region of antrum pylori represent a serious medical problem in humans and animals. Such localization of ulcers can influence the intrinsic descending nerve supply to the pyloric sphincter. The pyloric function is precisely regulated by intrinsic and extrinsic nerves. Impaired neural regulation could result in pyloric sphincter dysfunction and gastric emptying malfunction. The aim of the study was to determine the effect of gastric antral ulcerations on the density and distribution of intramural gastric descending neurons supplying the pyloric sphincter in pigs.

Methodology/Principal Findings

The experiment was performed on 2 groups of pigs: healthy gilts (n=6) and gilts with experimentally induced peptic ulcers in the region of antrum pylori (n=6). Gastric neurons supplying pyloric sphincter were labeled using the retrograde neuronal tracing technique (20μl of Fast Blue tracer injected into the pyloric sphincter muscle). After a week survival period the animals were sacrificed and the stomachs were collected. Then, the stomach wall was cross-cut into 0.5cm thick sections taken in specified intervals (section I - 1.5cm; section II - 3.5cm; section III - 5.5cm; section IV – 7.5cm) starting from the sphincter. Consecutive microscopic slices prepared from each section were analyzed under fluorescent microscope to count traced neurons. Obtained data were statistically analyzed. The total number of FB-positive perikarya observed within all studied sections significantly decreased from 903.3 ± 130.7 in control to 243.8 ± 67.3 in experimental animals. In healthy pigs 76.1 ± 6.7% of labeled neurons were observed within the section I, 23.53 ± 6.5% in section II and only occasional cells in section III. In experimental animals, as many as 93.8 ± 2.1% of labeled cells were observed within the section I and only 6.2 ± 2.2% in section II, while section III was devoid of such neurons. There were no traced perikarya in section IV observed in both groups of pigs.

Conclusions/Significance

Obtained results revealed for the first time significant impact of antral ulcerations on intramural descending nerve pathways supplying the pyloric sphincter in pigs, animals of increasing value in biomedical research and great economic importance.

Metabolomic perfusate analysis during kidney machine perfusion: the pig provides an appropriate model for human studies

INTRODUCTION

Hypothermic machine perfusion offers great promise in kidney transplantation and experimental studies are needed to establish the optimal conditions for this to occur. Pig kidneys are considered to be a good model for this purpose and share many properties with human organs. However it is not established whether the metabolism of pig kidneys in such hypothermic hypoxic conditions is comparable to human organs.

METHODS

Standard criteria human (n = 12) and porcine (n = 10) kidneys underwent HMP using the LifePort Kidney Transporter 1.0 (Organ Recovery Systems) using KPS-1 solution. Perfusate was sampled at 45 minutes and 4 hours of perfusion and metabolomic analysis performed using 1-D 1H-NMR spectroscopy.

RESULTS

There was no inter-species difference in the number of metabolites identified. Of the 30 metabolites analysed, 16 (53.3%) were present in comparable concentrations in the pig and human kidney perfusates. The rate of change of concentration for 3-Hydroxybutyrate was greater for human kidneys (p<0.001). For the other 29 metabolites (96.7%), there was no difference in the rate of change of concentration between pig and human samples.

CONCLUSIONS

Whilst there are some differences between pig and human kidneys during HMP they appear to be metabolically similar and the pig seems to be a valid model for human studies.