Having read with great interest the article by Cho et al,1 we would like to share a few comments regarding the variability of porcine liver anatomy and the segmental nature of the liver. Based on our research, surprisingly large interspecies variability has to be expected at the gross anatomy level of porcine liver. In domestic pigs, 3–6 anatomic liver lobes have been reported. Furthermore, in our experiments on Prestice Black-Pied pigs, the quadrate lobe was developed in 35% of cases2 (Figure 1A).FIGURE 1.: Morphological variability in porcine liver. A, In Prestice Black-Pied pigs, the quadrate lobe (white arrow) was not developed in 65% of cases.2 Asterisks mark PV segmental branches within a fibrous sheath. B, Depicted PV segmental branches according to Filipponi et al,3 the first branch of the PV goes to segment 1, the second branch is a common trunk for segments 6 and 7. The PV then curves medially and usually gives either 1 common branch or 2 separate branches for segments 5 and 8, before entering the liver parenchyma. After a short course of approximately 2.5 cm, it bifurcates into a branch for segment 2 and a common trunk for segments 3 and 4. C, Trifurcation of the PV was observed in 1 case (out of 6 studied) in our experiment.2 This third branch (arrowhead) supplied right medial lobe. D, The most common pattern of PV branching observed in our experiment2 with numbered liver segments. In the strict sense, the porcine liver can be divided in the right and left hemilivers, where the right division constitutes 19%–40% of the liver volume, and the left division constitutes 60%–81% of liver volume. Segmentation was done with the use of our freely available segmentation software LISA (Liver Surgery Analyser, available at: https://github.com/mjirik/lisa). E, Branching pattern of the PHA in domestic pig according to Filipponi et al3 with respective prevalence. F, Variability in the venous drainage of porcine liver into the CVC. Each depicted study is represented in corresponding color. Dashed line represents observed variability in the cited study; thin line represents smaller contribution to the drainage. Three or 4 hepatic veins have been reported. Segments 2 and 4 can drain directly to the CVC; segments 4, 5, and 8 can drain into a common trunk that forms the middle hepatic vein; alternatively, only the drainage for segments 5 and 8 can form the middle hepatic vein, whereas the left hepatic vein is formed by the drainage of segments 2, 3, and 4. A, Published with consent of Petra Kochová. C–F, Modified from Mik.2 CVC, caudal vena cava; GB, gall bladder; LHA, left hepatic artery; LISA, Liver Surgery Analyser (available at https://github.com/mjirik/lisa); PHA, proper hepatic artery; PV, portal vein; RHA, right hepatic artery.On the largest set of pig livers to date, Filipponi et al3 described different branching pattern of portal vein (PV) (Figure 1B). Furthermore, we observed PV bifurcation into the left and right branch just before entering the liver parenchyma in most cases (N = 5).2 However, in 1 case, we observed a PV trifurcation—the caudal branch supplied the right medial lobe (Figure 1C). In total, in our Prestice Black-Pied pigs, the right branch of the PV supplied 19%–40% of the liver, whereas the left branch 60%–81% of the liver (Figure 1D). Therefore, the volume ratio of the hemilivers was reversed when compared with humans. Concerning the branching variability of the proper hepatic artery (PHA), the branching scheme proposed by Cho et al1 has not yet been published. The most common branching pattern of the porcine PHA (63%) is shown in the Figure 1E. Liver drainage is usually assumed to be mediated by 3 hepatic veins with separate drainage of the caudate lobe/process; however, a separate drainage of segment 2 directly into the caudal vena cava has also been reported. Court et al4 reported 4 hepatic veins in agreement with Cho et al.1 Furthermore, we summarize the published variability in the branching pattern of the segmental veins in the Figure 1F.3,4,5 Although the Brisbane terminology has been adopted worldwide, we have 3 concerns regarding the definition of the liver segment. First, the borders of the segments are considered planar, whereas they are in fact undulated and form interdigitations. Second, the correlation of branching liver vascular beds is assumed. However, it has been demonstrated that individual liver vascular beds do not copy each other in the pattern of branching. Third, the definition of liver segment is circular, for the liver segment is usually considered as a part of the liver that is supplied/drained by its segmental vessel. On the other hand, the definition of the liver segment by the order of the generation of vessel branches is not satisfactory too; the liver has been reported to have 24 second-order PV branches; therefore, the grouping of these branches is arbitrary. The importance of pigs as a source of organs for the training of surgical techniques and xenotransplantation is indisputable, as is the research on the morphology of porcine liver vessels. In our commentary, we highlighted the already proven, significant inter-individual and breed-specific variability. Therefore, we strongly recommend computed tomography imaging before any pig liver resection.

Precise knowledge of the species-/breed-specific anatomy is important for accurate diagnosis and treatment. Existing literature has also been increasing in accordance with the growing demands of biomedical research, wherein mammals, including cats, have been used worldwide. Based on a vascular corrosion cast, complete duplication of the caudal vena cava (dCVC) was accidentally found in a 10-year-old male cat. The two separate symmetric veins corresponding to two caudal venae cavae cranially directed on both sides of the aorta; their first tributaries were the duplicated right and left deep circumflex iliac veins, and the median sacral vein ended in the right common iliac vein. At the L4 vertebra level, the left caudal vena cava crossed the aorta ventrally. It united with the right CVC immediately above the renal veins at the level of the cranial mesenteric artery (L2-L3). Embryologic knowledge is essential to understand the differences between the CVC variants in domestic mammals and the inferior vena cava in humans. However, views regarding the post-hepatic segment of the CVC during development vary considerably. Therefore, our case report also includes a summary of the CVC developmental theories and their clinical impact. We believe that this case and literature review contribute to the knowledge regarding the deep abdominal veins' variability, concomitant pathologies, and accurate diagnosis and surgery. Additionally, the latest robust studies demonstrating the exclusive participation of the caudal cardinal veins in the CVC development are discussed.

Bone regeneration after injury or after surgical bone removal due to disease is a serious medical challenge. A variety of materials are being tested to replace a missing bone or tooth. Regeneration requires cells capable of proliferation and differentiation in bone tissue. Although there are many possible human cell types available for use as a model for each phase of this process, no cell type is ideal for each phase. Osteosarcoma cells are preferred for initial adhesion assays due to their easy cultivation and fast proliferation, but they are not suitable for subsequent differentiation testing due to their cancer origin and genetic differences from normal bone tissue. Mesenchymal stem cells are more suitable for biocompatibility testing, because they mimic natural conditions in healthy bone, but they proliferate more slowly, soon undergo senescence, and some subpopulations may exhibit weak osteodifferentiation. Primary human osteoblasts provide relevant results in evaluating the effect of biomaterials on cellular activity; however, their resources are limited for the same reasons, like for mesenchymal stem cells. This review article provides an overview of cell models for biocompatibility testing of materials used in bone tissue research.

The vertebral arteries, as the first branches from the subclavian arteries, normally enter into the transverse foramen of the sixth cervical vertebra in dogs. This case report presents the nonstandard course of the left vertebral artery and unilateral asymmetry of the sixth cervical vertebra in a 14-year-old female mixed breed dog. The anomaly was an incidental finding during the preparation of a corrosion cast prepared for educational and scientific purposes. The left sixth cervical vertebra transverse foramen and the ventral lamina were not developed. The left vertebral artery originated normally from the left subclavian artery, but atypically entered into the transverse foramen of the fifth cervical vertebra. On the right side, the anatomical structures of the sixth cervical vertebra and the course of the right vertebral artery were normally developed. To our knowledge, this is the first case of such an anomaly described in a dog.

The aim of this paper is to summarize the current knowledge of the anatomy of domestic pig head and neck arteries for the needs of experimental surgery and imaging methods in biomedical research and translational medicine. The potential of this large animal model seems to be valuable also for the xenotransplantation of certain organs. Demands for the knowledge of morphological differences between analogous human structures and particular breeds are growing also in connection with the need for more precise planning of experiments or interpretation of the results. Deepening anatomical knowledge is allowed also by the development of imaging methods. The search was performed using the keywords “domestic pig” and “arteries of the head and neck“ in the MEDLINE database, PubMed interface.

Currently, there are at least 70 pure domestic pig breeds, but only certain breeds are used in biomedical research. The domestic pig liver is suitable for preclinical research because its size, physiology, and anatomy are similar to that of the human liver; in addition, there is a high degree of genetic similarity between the two species. For planning experiments and identifying improvements in both invasive and noninvasive methods of liver disease management, the morphological similarities and dissimilarities of the pig liver to its human counterpart must be taken into consideration along with sexual dimorphism and interindividual and interspecific variability. Recent histological evaluations based on stereological methods enable precise quantitative morphological estimates and guarantee their unbiased accuracy. The results thereof are crucial for revealing and assessing histological changes and can contribute to the optimization of study designs. New trends in computed tomography data processing have also been introduced. This review article summarizes the newest trends and findings in the field of porcine liver anatomy and histology as applicable to preclinical research.

Background: In patients with colorectal liver metastases, the possibility for radical liver resection can be limited by oxaliplatin-induced sinusoidal obstruction syndrome (SOS). This study investigates the potential of mesenchymal stem cells (MSC) to improve the outcome of liver resections in pigs with SOS. Materials and Methods: SOS was induced in all animals (n=20) on day 0. Animals in the experimental group (n=8) received allogeneic MSC on day 7. Liver resection was performed in all animals on day 14 and the animals were observed until day 28. Ultrasound volumetry, biochemical analysis and histological examination of liver parenchyma was performed during the follow-up period. Results: Six animals from the control group died prematurely, while all animals survived in the experimental group. According to histology, biochemical analysis and ultrasound volumetry, there were no significant differences between the groups documenting the effect of MSC. Conclusion: Single dose allogeneic MSC administration improved survival of animals with SOS undergoing partial liver resection. Further experiments with different timing of liver resection and MSC administration should be performed to investigate the effect of MSC in more detail.

Background: Using animal models in experimental medicine requires mapping of their anatomical variability. Porcine common carotid arteries (CCA) are often preferred for the preclinical testing of vascular grafts due to their anatomical and physiological similarity to human small-diameter arteries. Comparing the microscopic structure of animal model organs to their human counterparts reveals the benefits and limitations of translational medicine. Methods: Using quantitative histology and stereology, we performed an extensive mapping of the regional proximodistal differences in the fractions of elastin, collagen, and smooth muscle actin as well as the intima-media and wall thicknesses among 404 segments (every 1 cm) of porcine CCAs collected from male and female pigs (n = 21). We also compared the microscopic structure of porcine CCAs with segments of human coronary arteries and one of the preferred arterial conduits used for the coronary artery bypass grafting (CABG), namely, the internal thoracic artery (ITA) (n = 21 human cadavers). Results: The results showed that the histological structure of left and right porcine CCA can be considered equivalent, provided that gross anatomical variations of the regular branching patterns are excluded. The proximal elastic carotid (51.2% elastin, 4.2% collagen, and 37.2% actin) transitioned to more muscular middle segments (23.5% elastin, 4.9% collagen, 54.3% actin) at the range of 2-3 centimeters and then to even more muscular distal segments (17.2% elastin, 4.9% collagen, 64.0% actin). The resulting morphometric data set shows the biological variability of the artery and is made available for biomechanical modeling and for performing a power analysis and calculating the minimum number of samples per group when planning further experiments with this widely used large animal model. Conclusions: Comparison of porcine carotids with human coronary arteries and ITA revealed the benefits and the limitations of using porcine CCAs as a valid model for testing bioengineered small-diameter CABG vascular conduits. Morphometry of human coronary arteries and ITA provided more realistic data for tailoring multilayered artificial vascular prostheses and the ranges of values within which the conduits should be tested in the future. Despite their limitations, porcine CCAs remain a widely used and wellcharacterized large animal model that is available for a variety of experiments in vascular surgery. (C) 2019 Elsevier GmbH. All rights reserved.

Background: The most commonly used technique for PV reconstruction after pancreaticoduodenectomy (PD) using autologous venous grafts has some disadvantages which could be eliminated by usage of allogeneic grafts. This study examines the potential differences in characteristics of allogeneic grafts from caval system or portal system in pig which were not studied till now. Material and Methods: PD with PV reconstruction with allogeneic venous graft from PV or inferior vena cava (IVC) was performed in 26 pigs. The postoperative follow up took 4 weeks when biochemical markers of liver functions were monitored and Doppler ultrasonography controls were performed. Samples of PV together with interposed grafts were harvested at the end of experiment and histologically examined. Software models showed PV haemodynamics before and after the reconstruction and helped to identify areas with higher risk of thrombosis. Results: The native grafts of PV and IVC had different histological structure but they underwent morphological changes and were comparable at the end of experiment. Computer simulation showed areas with higher risk of thrombosis within the graft regions, in the zones at both anastomoses and partly downstream from the interposed graft. PVs reconstructed with grafts of larger diameter showed higher risk of thrombosis. The diameter of PV graft right after the interposition was significantly larger compared to IVC graft but it was comparable in later time points. The thrombosis of reconstructed PV occurred in 5 cases (4 in PV, 1 in IVC group). Conclusions: Allogeneic grafts of PV and IVC are suitable for PV reconstruction but PV shows higher risk of early postoperative thrombosis. This study support usage of allogeneic venous grafts from caval system for PV reconstruction after PD in clinical medicine when needed.

Background: It has been previously published that the frontal branch of the middle meningeal artery (MMA) is usually embedded in a bony canal (BC). Although the incidence of the BC was over 70%, this structure is currently omitted both in anatomical nomenclature and in most of the literature. We found the same gap pertaining to the grooves for the MMA on the skull base. The aims of our study were to assess the incidence and morphometry of the MMA BC and grooves on the skull base. Materials and methods: Computed tomography (CT) scans of 378 patients, 172 skull bases as well as 120 sphenoidal bones and 168 temporal bones, and 12 histological specimens from 3 men and 3 women and 3 different regions of the MMA course were assessed. Results: Based on CT scans, the incidence of the BC was 85.44% and was significantly higher in females than in males. Most of the canals and grooves were bilateral. The mean canal length was 17.67 mm, the mean transverse diameter 1.33 mm, and the mean distance from the superior orbital fissure (dFOS) was 26.7 mm. In the skull bases, the BC incidence was 70.07%, the mean canal length 10.74 mm, and the mean dFOS was 19.16 mm. The groove for the MMA on the temporal and sphenoidal bones was present in 99.42% and 95.35%, respectively. Histological specimens confirmed the presence of the MMA and accompanying vein/s. Conclusions: Based on our results, we suggest the addition of the BC and grooves for the middle meningeal vessels to the upcoming version of the Terminologia Anatomica.

The forced disruption of education in the summer semester 2019-2020 was an unprecedented situation also for the teaching of anatomy at Czech medical faculties. Due to the forthcoming final exam on Anatomy, the situation urgently required a fluent transition to the distance learning. In our manuscript we present our experiences and tips based also on experience from other anatomical departments and which can be used in similar crises for a continuous.

In teaching and learning human anatomy, anatomical autopsy and prosected specimens have always been indispensable. However, alternative methods must often be used to demonstrate particularly delicate structures. Corrosion casting of porcine organs with Biodur E20® Plus is valuable for teaching and learning both gross anatomy and, uniquely, the micromorphology of cardiovascular, respiratory, digestive, and urogenital systems. Assessments of casts with a stereomicroscope and/or scanning electron microscope as well as highlighting cast structures using color coding help students to better understand how the structures that they have observed as two-dimensional images actually exist in three dimensions, and students found using the casts to be highly effective in their learning. Reconstructions of cast hollow structures from (micro-)computed tomography scans and videos facilitate detailed analyses of branching patterns and spatial arrangements in cast structures, aid in the understanding of clinically relevant structures and provide innovative visual aids. The casting protocol and teaching manual we offer can be adjusted to different technical capabilities and might also be found useful for veterinary or other biological science classes.

Background: In clinical medicine, little is known about the use of allografts for portal vein (PV) reconstruction after pancreaticoduodenectomy (PD). Portal and caval systems are physiologically different, therefore the properties of allografts from caval and portal systems were studied here in a pig model. Materials and Methods: PD with PV reconstruction with allogeneic venous graft from PV or inferior vena cava (IVC) was performed in 26 pigs. Biochemical analysis and ultrasonography measurements were performed during a 4-week monitoring period. Computer simulations were used to evaluate haemodynamics in reconstructed PV and explanted allografts were histologically examined. Results: The native PV and IVC grafts varied in histological structure but were able to adapt morphologically after transplantation. Computer simulation suggested PV grafts to be more susceptible to thrombosis development. Thrombosis of reconstructed PV occurred in four out of five cases in PV group. Conclusion: This study supports the use of allografts from caval system for PV reconstruction in clinical medicine when needed.

INTRODUCTION:Corrosion casts (CCs) are used for the visualization and assessment of hollow structures. CCs with filled capillaries enable (with the help of imaging methods) to obtain data for mathematical organ perfusion modelling. As the processing is more difficult in case of organs with greater volume of the vasculature, mainly organs from small animals have been cast up to now. The aim of this study was to optimize the protocol of corrosion casting of different organs of pig. Porcine organs are relatively easily accessible and frequently used in experimental medicine.METHOD:Organs from 10 healthy Prestice Black-Pied pigs (6 females, body weight 35-45 kg), were used in this study (liver, spleen, kidneys and small intestine). The organs were dissected, heparin was administered into the systemic circulation and then the vascular bed of the organs was flushed with heparinized saline either in situ (liver) or after their removal (spleen, kidney, small intestine). All handling was done under the water surface to prevent air embolization. The next step was an intraarterial (in case of the liver also intraportal) administration of Biodur E20® (Heidelberg, Germany) resin. After hardening of the resin the organ tissue was dissolved by 15% KOH and the specimen was rinsed with tap water. Voluminous casts were stored in 70% denatured alcohol, the smaller ones were lyophilized. The casts were assessed with a stereomicroscope, computed and microcomputed tomography (CT and microCT), a scanning electron microscope (SEM) and high-resolution digital microscope (HRDM).RESULTS:High-quality CCs of the porcine liver, kidneys, spleen and small intestine were created owing to the sophisticated organ harvesting, the suitable resin and casting procedure. Macroscopic clarity was improved thanks to the possibility of resin dying. Scanning by CT was performed and showed to be a suitable method for the liver cast examination. MicroCT, SEM and HRDM produced images of the most detailed structures of vascular bed. Despite the fact that SEM seems to be an irreplaceable method for CCs quality control, it seems that this modality could be partly replaced by HRDM. MicroCT enabled to obtain data about three-dimensional layout of the vascular bed and data for mathematical modelling of organ perfusion. With regard to the quality of the CCs, they could also be used to teach human anatomy.CONCLUSIONS:The protocol of the corrosion casting of the porcine liver, kidneys, spleen and small intestine CCs was optimized. Thanks to different imaging methods, the CCs can be used as a source of data on three-dimensional architecture of the vascular bed. These data can be used for mathematical modeling of organ perfusion which can be helpful for example for optimization of organ resections.Key words: corrosion casts microvasculature Biodur E20® domestic pig animal model.

The pig is a large animal model that is often used in experimental medicine. The aim of this study was to assess, in normal pig livers, sexual dimorphism in the normal fraction of hepatic interlobular and intralobular connective tissue (CT) in six hepatic lobes and in three macroscopical regions of interest (ROIs) with different positions relative to the liver vasculature. Using stereological point grids, the fractions of CT were quantified in histological sections stained with aniline blue and nuclear fast red. Samples (415 tissue blocks) were collected from healthy piglets, representing paracaval, paraportal and peripheral ROIs. There was considerable variability in the CT fraction at all sampling levels. In males the mean fraction of interlobular CT was 4.7 ± 2.4% (mean ± SD) and ranged from 0% to 11.4%. In females the mean fraction of the interlobular CT was 3.6 ± 2.2% and ranged from 0% to 12.3%. The mean fraction of intralobular (perisinusoidal summed with pericentral) CT was <0.2% in both sexes. The interlobular CT represented >99.8% of the total hepatic CT and the fractions were highly correlated (Spearman r = 0.998, P <0.05). The smallest CT fraction was observed in the left medial lobe and in the paracaval ROI and the largest CT fraction was detected in the quadrate lobe and in the peripheral ROI. For planning experiments involving the histological quantification of liver fibrosis and requiring comparison between the liver lobes, these data facilitate the power analysis for sample size needed to detect the expected relative increase or decrease in the fraction of CT.

AIM:Papillary renal cell carcinoma type 1 (pRCC1) represents the second most common type of malignant renal epithelial tumour. The origin of its characteristic appearance, its growth mechanism, and the long-term efficiency of its surgical treatment remain uncertain. Our aim was to determine typical characteristics of surgically treated pRCC1.METHODS:pRCC1 was verified in 83 of 1,629 (5.1%) kidney tumours surgically treated in the period of January 2007-January 2016. The clinical and radiological characteristics, type of surgery, histopathology results and follow up data were recorded. Spearman correlation, Kruskal-Wallis analysis of variance, Fisher's exact, and chi-square test were used to analyse appropriate variables. The overall survival rate was evaluated using the Gehan-Wilcoxon test and the Cox proportional hazards model.RESULTS:The mean tumour size was 52.0 mm (15-180); 98.8% of the tumours showed a spherical shape and in 82.1%, exophytic growth was observed. Partial nephrectomy was performed in 80.7%. A majority (81.9%) were classified as pT1. Tumours, 89.2% of them, belonged to Fuhrman grade 1 or 2. The mean follow-up was 46.8 months. The overall survival was associated with pT category (p ≤ 0.0001).CONCLUSIONS:Typical signs of pRCC1 are a spherical shape, exophytic growth and low Fuhrman's grade. More than three-fourths of pRCC1 could be treated by the nephron-sparing surgery.

BACKGROUND:Pigs are frequently used as animal models in experimental medicine. To identify processes of vascular development or regression, vascular elements must be recognised and quantified in a three-dimensional (3D) arrangement. Vascular corrosion casts enable the creation of 3D replicas of vascular trees. The aim of our study was to identify suitable casting media and optimise the protocol for porcine liver vascular corrosion casting.MATERIALS AND METHODS:Mercox II® (Ladd Research, Williston, Vermont, USA) and Biodur E20® Plus (Biodur Products, Heidelberg, Germany) were tested in 4 porcine livers. The resins (volume approximately 700 mL) were injected via the portal vein. Corrosion casts were examined by macro-computed tomography, micro-computed tomography and scanning electron microscopy.RESULTS:For hepatectomies, the operating protocol was optimised to avoid gas or blood clot embolisation. We present a protocol for porcine liver vascular bed casting based on corrosion specimens prepared using Biodur E20® epoxy resin.CONCLUSIONS:Only Biodur E20®Plus appeared to be suitable for high-volume vascular corrosion casting due to its optimal permeability, sufficient processing time and minimum fragility. Biodur E20® Plus is slightly elastic, radio-opaque and alcohol-resistant. These properties make this acrylic resin suitable for not only vascular research but also teaching purposes.