Anatomy Of Pig Research Articles

Abstract 13000: The Effect of Flow Dynamics on the Neotissue Formation of 3D Printed Tissue Engineered Vascular Graft

Introduction: Complex vascular reconstruction such as that of the right ventricle to pulmonary artery (RVPA) and the aortic arch remains challenging due to the various 3D geometry of each patient. Tissue-engineered vascular grafts (TEVG) possess not only excellent antithrombotic and anti-infective properties but also the ability to grow as the patient matures. 3D printed patient-specific TEVG can maintain optimal hemodynamics with the growth of the patient and may improve surgical outcomes. We applied our unique 3D printing technology to create patient-specific TEVG for RVPA and the aortic arch. Methods: We acquired MRI and 4-dimensional flow data for the native anatomy of pigs (n=8) to design a patient-specific TEVG of the pulmonary artery (n=5) and the aortic arch (n=3) 4 weeks prior to surgery. The optimal shape of the branched vascular graft (n=8) was designed using a computer-aided design informed by computational flow dynamics analysis. We manufactured and implanted the grafts into the RVPA or aortic arch in the porcine model. The grafts were explanted after surgery at 8 - 12 weeks for evaluation. Pre- and post-op implant flow dynamics data in MRI and histology were analyzed. Results: The local neointimal thickness of TEVG in histology and the corresponding area of wall shear stress in 4D MRI were measured. Low wall shear stress, an aspect of MRI flow analysis, demonstrated a significant correlation with decreased neointimal thickness through histology (R2=0.65, P=0.016), which suggested optimal shape and design is important for appropriate neotissue formation. Conclusions: Our 3D printed custom designed TEVG demonstrated optimal anatomical fit maintaining ideal flow dynamics can attenuate neointimal hyperplasia and appropriate neovessel formation.

Radiological Arterial Anatomy in Mature Microminipigs as a Pre-clinical Research Model in Interventional Radiology.

To define the radiological arterial anatomy in mature microminipigs as a pre-clinical research animal model in interventional radiology. Five female microminipigs (weighing 20.9 ± 2.9kg) were used in this study. Under general anesthesia, computed tomography (CT) angiography was performed using a 16-slice CT scanner. CT was performed 12s after initiation of an intravenous injection of 40ml of nonionic contrast media at 3.0ml/second using a power injector. The transverse CT angiography images were evaluated using a digital imaging and communication in medicine viewer, and the diameters of the following 41 arteries were measured.: ascending aorta, descending aorta, thoracoabdominal aorta, abdominal aorta, pulmonary artery trunk, both pulmonary, brachiocephalic artery, short common bicarotid, both common carotid artery, subclavian, bronchial, internal mammary, celiac, common hepatic, left lateral hepatic, middle hepatic, left hepatic, gastroduodenal, cranial duodenopancreatic, splenic, left gastric, cranial mesenteric, ileocolic , bilateral colic artery, caudal mesenteric, cranial rectal, renal, both external iliac arteries, internal iliac common trunk, and both internal iliac and femoral arteries. The microminipigs' vascular anatomy was the same as domestic pig anatomy and similar to human anatomy. The diameter of the aorta (ascending to abdominal) was 17.1-7.0mm, iliac and femoral arteries (internal iliac common trunk to femoral artery): 5.5-3.8mm, pulmonary arteries: 9.3-14.7mm, and major first aortic branches (e.g., celiac or brachiocephalic artery): 2.2-9.2mm. This study defined the microminipig arterial anatomy in the trunk.

Experimental near-infrared spectroscopy-guided minimally invasive segmental artery occlusion.

Minimally invasive staged segmental artery (SA) coil- and plug embolization is a new method for paraplegia prevention associated with extensive aortic procedures. Near-infrared spectroscopy of the paraspinal collateral network (cnNIRS) has emerged as a non-invasive method for spinal cord monitoring. The aim of this study was to evaluate cnNIRS to guide minimally invasive SA occlusion. In a chronic large animal experiment, 18 juvenile pigs underwent two-stage minimally invasive staged SA coil- and plug embolization for complete SA occlusion. Coil-embolization was performed either by SA main stem occlusion (characteristic of pig anatomy) or separately for the left- and right SA. Lumbar cnNIRS was recorded during and after the procedure. Neurological status was assessed up to 3 days after complete SA occlusion. Mean time from SA coil embolization to minimum cnNIRS values was 11 ± 5 min with an average decrease from 101 ± 2% to 78 ± 8% of baseline (difference: -23 ± 9, P < 0.001). Lumbar cnNIRS demonstrated significant differences between left and right when SAs were occluded separately in all cases (-7 ± 4%, 1 min after first SA occlusion; P = 0.001). Permanent paraplegia occurred in 2 (11%) and any kind of neurological deficit-temporary or permanent-in 7 animals (39%). Association between lumbar cnNIRS and neurological outcome after minimally invasive staged SA coil- and plug embolization suggests positive correlation (R = 0.5, P = 0.052). Lumbar cnNIRS independently reacts to unilateral SA occlusion. cnNIRS-guided SA occlusion is feasible and may become a useful adjunct facilitating adequate and complete vessel occlusion.

Veterinary care of guinea pigs

Background: Guinea pigs have become very popular in the pet trade and have been extensively bred for colour and coat mutations. They should not be considered as just a children’s...

Percutaneous cannulation for extracorporeal membrane oxygenation (ECMO): A method for pig experimental models

Pigs are often used for experimental models of cardiogenic shock, cardiac arrest or acute lung injury with veno-arterial (VA) or veno-venous (VV) extracorporeal membrane oxygenation (ECMO) implementation. Percutaneous (as opposed to surgical) cannulation in experimental models has potential advantages, including, less surgical trauma or stressful stimuli and less bleeding complications when compared to open chest cannulation. However, pig anatomy can also be a challenge because of the deep location and angled anatomy of the femoral artery. The Seldinger technique and the use of a percutaneous cannulation kit is feasible in pigs.Summarized here we present (Graphical Abstract):•Percutaneous ECMO cannulation method for non-cardiac surgeon.•Establishment of this simple and rapid methods for pig experimental models.•Predictable complications of this method.

Animal Models Used to Simulate Retinal Artery Occlusion: A Comprehensive Review.

PurposeTo present an overview of animal models of retinal artery occlusion (RAO).MethodsThrough a systematic literature search in PubMed and Embase, papers describing methods of inducing RAO in animal models were included. The identified methodologic approaches were presented in a narrative synthesis and compared with RAO in humans.ResultsIn total, 83 papers reporting on 88 experiments were included. Six different species were used with rodents and monkeys being the most common, and a minority were performed using cats, dogs, rabbits, or pigs. The anatomy of pigs and monkeys resemble that of humans most closely. The two most frequently used methods were laser-induced occlusion or ligation of the arteries. Other methods included raised intraocular pressure, arterial clamping, administration of vasoconstricting agents, the use of an occluder, embolization, and endovascular approaches to induce occlusion. In general, occlusions lasted for only 30 to 90 minutes, often followed by reperfusion.ConclusionsAlthough a broad range of methods have previously been used, they all have limitations. Preferably, the methods should imitate the human disease as closely as possible and avoid damaging other structures. Therefore, monkeys followed by pigs are to be preferred and ligation or clamping may be a suitable model in larger animals as there is a potential to isolate and occlude the retinal artery only. Being less invasive, laser-induced occlusion is another suitable approach.Translational RelevanceThis review aims at assisting researchers in deciding on the most ideal experimental setting, and thereby increase the translational value to human disease.

Tailored Pig Models for Preclinical Efficacy and Safety Testing of Targeted Therapies.

Despite enormous advances in translational biomedical research, there remains a growing demand for improved animal models of human disease. This is particularly true for diseases where rodent models do not reflect the human disease phenotype. Compared to rodents, pig anatomy and physiology are more similar to humans in cardiovascular, immune, respiratory, skeletal muscle, and metabolic systems. Importantly, efficient and precise techniques for genetic engineering of pigs are now available, facilitating the creation of tailored large animal models that mimic human disease mechanisms at the molecular level. In this article, the benefits of genetically engineered pigs for basic and translational research are exemplified by a novel pig model of Duchenne muscular dystrophy and by porcine models of cystic fibrosis. Particular emphasis is given to potential advantages of using these models for efficacy and safety testing of targeted therapies, such as exon skipping and gene editing, for example, using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated system. In general, genetically tailored pig models have the potential to bridge the gap between proof-of-concept studies in rodents and clinical trials in patients, thus supporting translational medicine.

A guide to the porcine anatomy for the interventional electrophysiologist. Fluoroscopy and high density electroanatomical mapping.

Invasive electrophysiology is a rapidly developing field of cardiovascular science with a constant need for inventions and testing of new technologies and concepts. Despite the swine model being an established tool in biomedical research no comprehensive guide for interventional electrophysiologists exists. The aim of the current article is to provide a practical overview of the pig anatomy, fluoroscopic views, and corresponding high density electroanatomic maps using a novel mapping system and a practical guide for interventions and techniques. In 17 pigs, fluoroscopic images of the right atrium, coronary sinus (CS), left atrium, and pulmonary veins as well as the right and left ventricles were obtained and correlated with ultra-high density electroanatomic maps and gross anatomy. Pitfalls of the porcine anatomy are precisely addressed, and alternative access techniques to overcome those issues are suggested. Important differences to human electrophysiological studies are highlighted. Complementary models such as cardiac ischemia induction or renal and pulmonary artery denervation are discussed in detail.

Anatomy and bronchoscopy of the porcine lung. A model for translational respiratory medicine.

The porcine model has contributed significantly to biomedical research over many decades. The similar size and anatomy of pig and human organs make this model particularly beneficial for translational research in areas such as medical device development, therapeutics and xenotransplantation. In recent years, a major limitation with the porcine model was overcome with the successful generation of gene-targeted pigs and the publication of the pig genome. As a result, the role of this model is likely to become even more important. For the respiratory medicine field, the similarities between pig and human lungs give the porcine model particular potential for advancing translational medicine. An increasing number of lung conditions are being studied and modeled in the pig. Genetically modified porcine models of cystic fibrosis have been generated that, unlike mouse models, develop lung disease similar to human cystic fibrosis. However, the scientific literature relating specifically to porcine lung anatomy and airway histology is limited and is largely restricted to veterinary literature and textbooks. Furthermore, methods for in vivo lung procedures in the pig are rarely described. The aims of this review are to collate the disparate literature on porcine lung anatomy, histology, and microbiology; to provide a comparison with the human lung; and to describe appropriate bronchoscopy procedures for the pig lungs to aid clinical researchers working in the area of translational respiratory medicine using the porcine model.

The application of humane slaughterhouse practices to large-scale culling

Mass culling is a strategy used inthe management of infectious disease outbreaks. The risk of disease spread due to animal transportation often precludes the use of slaughterhouses for this purpose, though they have been used on occasion. Consequently, culling takes place in the less-than-standardised environment on the farm. Regardless of where the cull occurs, the methods chosen to handle and kill the animals must preserve their welfare. This paper attempts to apply the best welfare practices from the controlled environment of the slaughterhouse to the mass culling of ruminants, pigs and poultry. It investigates the key welfare challenges and identifies astute planning executed by competent personnel as a crucial success factor. The urgency; capacity; species, type and age of the animal; personnel; and availability of equipment determine the restraint and killing methods used. The use of good on-farm restraining facilities and mobile killing devices can reasonably be expected to maintain welfare standards for ruminants and poultry. The pig's anatomy, natural behaviour, wide age range and housing types present additional challenges. Objective monitoring throughout the operation is vital for implementing immediate corrective measures whilst also informing procedural reviews. The authors suggest a monitoring tool based on a system currently used in abattoirs, but its limitations must first be validated.

Anatomical anomalies of the laryngeal branches of the vagus nerve in pigs (Sus scrofa)

To delineate the anomaly and frequency of their occurrence in a pig model, we reported the topography of the vagus laryngeal branches and compared the differences with humans. Thirty sides of cervical vagus nerve in 15 fresh cadavers (Sus scrofa) were microdissected. We measured the branch diameters and lengths of the laryngeal branches using a Vernier caliper with a resolution of 0.01 mm. Two patterns of the vagus laryngeal branches were shown: 56.7% with the cranial laryngeal nerve (CLN) and 43.3% without the CLN. The diameters and the length of the CLN were not affected by the side of the neck (P > 0.05), but the diameters of the recurrent laryngeal nerve (RLN) and the nodose ganglion were significantly different between left and right sides (P < 0.05). The left RLN was thinner than the right side in diameter (P < 0.05). Four of the 30 sides had anastomoses between the vagus and the cervical sympathetic chain. There were some differences between the pig anatomy and human anatomy, but the patterns were largely similar. The similarities support the utility of this model, which is closer in size to humans than the standard rodent models.

Comparative phenotypic and molecular characterization of porcine mesenchymal stem cells from different sources for translational studies in a large animal model

Mesenchymal stem cells have demonstrated their potentiality for therapeutic use in treating diseases or repairing damaged tissues. However, in some cases, the results of clinical trials have been disappointing or have not worked out as well as hoped. These disappointing results can be attributed to an inadequate or insufficient preclinical study. For medical and surgical purposes, the similarities between the anatomy of pig and human make this animal an attractive preclinical model. In this sense, for mesenchymal stem cell-based therapy, it is strongly necessary to have well characterized animal-derived mesenchymal stem cell lines to validate preclinical effectiveness of these cells. In this work, porcine mesenchymal stem cells (pMSCs) were isolated from bone marrow, adipose tissue and peripheral blood and compared in terms of differentiation potential, cell surface markers and gene expression. Our results demonstrated that the isolation and in vitro expansion protocols were feasible and effective. The data presented in this work are relevant because they provide an extensive phenotypic characterization; genetic study and differentiation behavior of the most commonly used stem cell lines for clinical practices. These pMSCs are widely available to scientists and could be a valuable tool to evaluate the safety and efficacy of adoptively transferred cells.

Appropriate Donor Size for Porcine Liver Xenotransplant

Owing to an imbalance between demand and supply, which is more prominent in pediatric transplant, every year more patients lose their lives on waiting lists. In addition to the use of deceased-donor split and living-donor organs, xenotransplant could provide a solution if associated problems, such as immunologic and physiologic ones, are solved. This study sought to analyze the surgical aspects for liver xenotransplant in a porcine model. Landrace pigs (n=22, 23 to 37 kg) underwent a laparotomy under general anesthesia. The hepatic hilum was prepared and the common bile ducts, common hepatic artery, portal vein, supra- and infrahepatic inferior vena cava were identified. The length and diameter of each vessel and bile duct and the weight of the liver were measured. Pearson tests showed a clear correlation between the increase of the pigs' weight and the livers' weight, and the length of the vessels and the bile ducts. We did not find a clear correlation between the increase of the pigs' liver weight and the diameters of the vessels and the bile duct. As the first reporting, this study on xenotransplants from the surgical point of view, we postulate that it could be possible to estimate the size of the liver and the proper length of its vessels and bile duct by weighing only the pigs. It was not feasible to match the diameter of mentioned structures by the livers' weight. However, the weight of pig's liver as well as vascular anatomy of pigs appeared to be suitable alternative for the human liver.

Perspectives in Clinical Hemorheology and Microcirculation: Review of the Conference of the German Society for Clinical Microcirculation and Hemorheology 2010

During the 29th conference of the German Society for Clinical Microcirculation and Hemorheology – held in the Freie Universitat Berlin a broad range of different topics of experimental and clinical studies in the field were presented. A special spotlight was dedicated to the Conference President’s (Prof. Dr. J. Plendl, Head of the Department of Veterinary Anatomy) scientific area “Anatomical and Experimental Microcirculation” [5, 6, 9, 13]. Of special interest were the angiogenetic studies: Examinations of the influence of PDGF-BB on adipose-tissue derived stem cells and how these influence angiogenesis [9] and the angiogenesis and healing with non-shrinking, fast degradable PLGA/CaP scaffolds in critical-sized defects in the rabbit femur with or without osteogenically mesenchymal stem cells were evaluated [6]. The influence of angiopoetins on angiogenesis was also analyzed [5]. In an anatomical study, it was then shown how the specific vascular anatomy of pigs allows acute infrarenal aortic occlusion without hind limb ischemia and stepwise occlusion without clinical signs [13]. Thereafter, studies from the field of Clinical Hemorheology were presented. A study of Franke et al. showing for the first time the different impact of radiographic contrast media on the morphology of human arterial versus venous endothelial cells was presented [8]. In addition, talks on monocytes – the influence of the sorting process on cell function [17] and on monocyte adhesion to endothelium exposed to nonuniform shear stress [2] were given. Also the shear stress required for tether formation of neonatal and

Renal–Portal Shunt Ameliorates Renovascular Hypertension in Pigs

Renovascular hypertension is the most common curable form of secondary hypertension. Renin angiotensin system activation depends on the balance between renin production by the kidney and renin degradation by the liver. Thus, we aimed to examine whether deviation of renin-rich blood from the affected kidney into the portal circulation (portalization) can ameliorate renovascular hypertension. We selected a porcine model of unilateral renal artery stenosis because the pig's anatomy and physiology are comparable to those of humans and because pigs have already been found capable of developing chronic renovascular hypertension. Angiography and ultrasonography were deliberately used to evaluate renal artery stenosis and the renal-portal shunt. Histology was used to examine the effects of portalization on the kidney and liver after a period of two months. As expected, following the creation of a left renal artery stenosis both renin activity and mean blood pressure measurements increased from 1.23 +/- 0.06 ng/mL/h and 85.6 +/- 0.5 mm Hg at baseline to 4.59 +/- 0.02 ng/mL/h and 126 +/- 1.76 mm Hg, respectively. After portalization renin activity returned to the normal range (1.59 +/- 0.07 ng/mL/h) followed by a concomitant reduction of mean blood pressure to 91 +/- 2 mm Hg. Moreover, a significant correlation was observed between changes in renin activity and blood pressure measurements during the two stages of the experiment. Both the kidney and liver remained macroscopically and microscopically intact at the end of the experiment. Portalization of the affected kidney can ameliorate renovascular hypertension and therefore, it might be of benefit in those individuals with fibromascular or atheromatous lesions in the renal artery or its branches not amenable to balloon angioplasty or surgical revascularization.

A stereo imaging system for the metric 3D recovery of porcine surface anatomy

We have succeeded in capturing porcine 3D surface anatomy in vivo by developing a high‐resolution stereo imaging system. The system achieved accurate 3D shape recovery by matching stereo pair images containing only natural surface textures at high (image) resolution. The 3D imaging system presented for pig shape capture is based on photogrammetry and comprises: stereo pair image acquisition, stereo camera calibration and stereo matching and surface and texture integration. Practical issues have been addressed, and in particular the integration of multiple range images into a single 3D surface. Robust image segmentation successfully isolated the pigs within the stereo images and was employed in conjunction with depth discontinuity detection to facilitate the integration process. The capture and processing chain is detailed here and the resulting 3D pig anatomy obtained using the system presented.

Hand-assisted laparoscopic donor hepatectomy for living related transplantation in the porcine model.

Use of a minimally invasive approach for donor nephrectomy has proven to be safe and feasible and has increased the pool of donors for living related renal transplantation. A porcine study to assess the safety and feasibility of performing laparoscopic donor hepatectomy was performed, with potential application to human liver donors for living related liver transplantation. Of the 10 50-kg pigs used, 2 underwent an open left lateral segmentectomy to define the pig anatomy. Two subsequent pigs underwent a laparoscopic liver resection to refine the technique. Subsequently, under sterile conditions, six pigs underwent laparoscopic liver resection with use of a hand-assisted technique for long-term study. Diameters and lengths of hepatic vessels and ducts were measured. Operative blood loss, operative time, and warm ischemia duration were noted. Biopsies of the resected specimens were done to look for ischemia. There was one operative death in the group with chronic liver failure, due to stapler misfire and hemorrhage from the left hepatic vein. The only instance of morbidity was a wound infection. The resected liver had minimal warm ischemia time and microscopic changes, which led us to believe that the organ was suitable for transplantation. We believe that this long-term study establishes the feasibility of this procedure.

Laparoscopic biliopancreatic diversion with a duodenal switch for morbid obesity: a feasibility study in pigs.

Biliopancreatic diversion with a duodenal switch is an emerging open procedure that appears as effective as other bariatric operations. Our goal was to determine the safety and feasibility of performing this procedure using a laparoscopic approach in a porcine model. Six 50-kg pigs underwent surgery. Intake was restricted with a sleeve gastrectomy, and malabsorption was obtained by creating a Roux-en-Y. The Roux limb served as a 150-cm alimentary channel following anastomosis to a transected proximal duodenum, while the other limb, or biliopancreatic channel, transported digestive juices. Where the two limbs joined, a 100-cm common channel was formed. The operation was completed in a mean time of 4.5 hours. Two of the six pigs had an intraoperative duodenoenterostomy anastomotic leak detected on methylene blue testing. This leakage was thought to be related to pig anatomy and is not expected to be a problem in humans. At necropsy, all anastomoses were patent, and there were no enteroenterostomy leaks or mesenteric torsions. On the basis of the porcine model, laparoscopic biliopancreatic diversion with a duodenal switch is anticipated to be feasible and safe in humans. Substantial weight loss combined with the benefits of laparoscopic surgery can be expected.

The porcine bronchial artery: surgical and angiographic anatomy.

The pig is often used in experimental studies on the significance of bronchial artery circulation, but the anatomy of this artery is only poorly described. The purpose of this study was to improve the anatomical basis for experimental studies on the porcine bronchial artery circulation. The origin of the artery from the aorta is described in 32 pigs. Heart-lung blocks were perfused with saline and removed in 16 pigs, and the broncho-oesophageal orifice was identified and cannulated. In these 16 specimens the intrapulmonary ramification was studied by angiography, and the extrapulmonary distribution and supply area by injection of Evans Blue. The broncho-oesophageal artery originated from the aorta as a single trunk in 91%. Angiography showed that each principal bronchus was accompanied by 2 bronchial artery branches far into the lung parenchyma. The central branching pattern of the artery between the aorta and the principal bronchi was divided into 3 subtypes. Evans Blue showed communication with the whole mediastinum. The anatomical relations are described. It is concluded that the broncho-oesophageal artery divides to follow each bronchus with 2 bronchial branches. A nomenclature for these branches is suggested. The pig anatomy is suited for experimental investigations on the bronchial circulation.

Anatomy of the Guinea Pig

The guinea pig is so widely used in laboratories that it has become synonymous in common speech with But until now there has been no complete and accurate anatomy of this otherwise familiar creature. Cavia has remained uncharted territory for experimenters who come to it without previous experience. Gale Cooper and Alan L. Schiller here provide a thorough description of guinea pig anatomy in a text illustrated with about four hundred separate drawings. It is a detailed, complete, and practical guide to the gross morphology of the animal. Nomenclature has been standardized according to the Nomina Anatomica Veterinaria. The authors' dissections have been carefully correlated with the published literature on guinea pig anatomy, and numerous references are given. This book sets a new standard of beauty and clarity in anatomical illustration. Dr. Cooper's drawings not only provide anatomical information with the utmost in accuracy and fidelity, they are in themselves an aesthetic triumph. Her pencil drawings have been made by a technique that requires specially made paper and demands unusual skill from the artist; closely identified with the famous illustrator Max Brodl, this method is now rarely employed. Researchers in immunology, hematology, physiology, biochemistry, pharmacology, reproductive biology, comparative anatomy, and taxonomy, among other fields, will turn to this anatomy as a reliable guide to a favored experimental species.