Preparation of a pig experimental model of defective colon anastomosis - review.

Anastomotic leak is a serious complication in colorectal surgery. The problem of intestinal anastomosis healing disorders is dealt with by a number of experimental studies, especially in applied research. The design of animal models is diverse and the results of individual studies are difficult to compare. This paper summarizes the main issues of planning animal models of intestinal anastomoses, which are discussed individually. The main part of the text is a description of the defective intestinal anastomosis model of the pig. The anastomosis is constructed in the model with a localized mucosal protrusion. The animals are monitored for 3 weeks postoperatively, the clinical condition and changes in vital values and laboratory parameters are monitored, and CT examinations are performed at defined points. At the end of the observation period, samples are taken, macroscopic findings in the abdominal cavity are evaluated, adhesions are scored, and signs of leakage or passage disorders are assessed. The preparations are evaluated histologically both by standard methods analyzing vascularity, inflammatory infiltration and the proportion of collagen, and by methods developed de novo for the needs of the experiment, such as the analysis of the integrity of the intestinal wall at the site of the mucosal protrusion. We value the experimental model for the possibility of a systematic and detailed analysis of the healing state of the anastomosis in combination with a detailed observation protocol, which produces clinically relevant results.

Intestinal Anastomotic Healing: What do We Know About Processes Behind Anastomotic Complications.

Colorectal surgery has developed rapidly in the recent decades. Nevertheless, colorectal anastomotic leakage continues to appear postoperatively in unpleasant rates and leads to life-threatening conditions. The development of valid complication-preventing methods is inefficient in many aspects as we are still lacking knowledge about the basics of the process of anastomotic wound healing in the gastrointestinal tract. Without the proper understanding of the crucial mechanisms, research for prevention of anastomotic leakage is predestined to be unsuccessful. This review article discusses known pathophysiological mechanisms together with the most lately found processes to be further studied. The aim of the article is to facilitate the orientation in the topic, support the better understanding of known mechanisms and suggest promising possibilities and directions for further research.

Permanent intravenous access in experimental surgery ­ our experience

Introduction: Permanent intravenous access is usually required in pigs used for surgical experiments, not only to enable repeated blood sample collections. The aim of this study was to evaluate the patency and complications of vascular access ports (VAP) implanted in pigs included in different surgical experiments. Methods: VAPs were implanted via the external jugular vein in a total of 211 pigs from 7 different experiments. All observed complications were retrospectively evaluated. Results: No complications were observed in 157 animals (74.4%). Complications of the least severity were edema or seroma around the port which were observed in 12 (5.7%) and 3 (1.4%) animals, respectively. Temporary problems with aspiration of blood via the port occurred in 13 animals (6.2%). The most severe complications which prevented the use of the VAP for aspiration and application were recorded in 26 animals (12.3%). These complications included: abscess formation around the port (12 animals), skin necrosis over the port (2 animals), partial wound dehiscence (2 animals) and loss of the VAP function due to an unspecified cause (10 animals). Removal of the VAP was not needed in any of the animals and none of the animals had to be excluded from the experiment due to the complications. The VAP can also be used for safe administration of iodine contrast agent during CT examination. Conclusion: Despite the observed complications the VAP is suitable as permanent intravenous access in pigs used for surgical experiments. This method helps to minimize the stress of the animals in the postoperative period and to reduce the number of experimental animals.

Repopulation of decellularized pig scaffolds: Promising approach for liver tissue engineering.

Repopulation of decellularized tissue with cells is a very promising approach in tissue engineering, with liver tissue engineering not being an exception. Decellularized liver scaffolds can serve as an excellent 3D environment for recellularization as it maintain tissue-specific microarchitecture of ECM proteins with important spatial cues for cell adhesion, migration, growth and differentiation. Moreover, by using autologous cells the newly constructed graft should lack immunogenicity in the host organism and thus eliminate the need for immunosuppressive therapy in the post-transplant period. This review provides an overview of liver decellularization and repopulation experiments done so far while highlighting the advances as well as pin-pointing the challenges that remain to be solved.

Variability of facial movements in relation to sexual dimorphism and age: three-dimensional geometric morphometric study.

The aim of this study was to introduce suitable imaging technique and analytical methods for a detailed description of the facial movements in relation to sexual dimorphism and age in adult individuals. Removing of size factor from the analysis, we hypothesised that there will be no significant intersexual difference in facial mobility. We assume facial movements to be more pronounced in the older age category due to increasing the facial surface. We have compared five facial movements - raising eyebrows, closing eyes, pursing of the lips, inflating of the cheeks and smile - in relation to neutral expression of the human face. The material sample comprised three-dimensional facial surface models of healthy adult individuals of the Czech nationality (63 females, 58 males). Methods of geometric morphometry and multivariate statistics were used. Local tissue motion due to facial movements was expressed using colour-coded maps. The movement showing significant intersexual difference was inflating of the cheeks. Ageing in both sexes has significantly influenced the facial mobility on average after 50 years of age. Changes related to senescence have occurred in eye closing, smile and inflating of the cheeks. An enlarged facial surface has been noted in the group of individuals belonging to the older age category, what is probably the result of increased manifestation of skin folds and wrinkles. This is related to the loss of skin elasticity and overall weakening of the underlying muscles, especially in the infraorbital and cheeks area.

Effects of increased myocardial tissue concentration of myristic, palmitic and palmitoleic acids on the course of cardiac atrophy of the failing heart unloaded by heterotopic transplantation.

The present experiments were performed to evaluate if increased heart tissue concentration of fatty acids, specifically myristic, palmitic and palmitoleic acids that are believed to promote physiological heart growth, can attenuate the progression of unloading-induced cardiac atrophy in rats with healthy and failing hearts. Heterotopic abdominal heart transplantation (HT(x)) was used as a model for heart unloading. Cardiac atrophy was assessed from the ratio of the native- to-transplanted heart weight (HW). The degree of cardiac atrophy after HT(x) was determined on days 7, 14, 21 and 28 after HT(x) in recipients of either healthy or failing hearts. HT(x) of healthy hearts resulted in 23+/-3, 46+/-3, 48+/-4 and 46+/-4 % HW loss at the four time-points. HT(x) of the failing heart resulted in even greater HW losses, of 46+/-4, 58+/-3, 66+/-2 and 68+/-4 %, respectively (P<0.05). Activation of "fetal gene cardiac program" (e.g. beta myosin heavy chain gene expression) and "genes reflecting cardiac remodeling" (e.g. atrial natriuretic peptide gene expression) after HT(x) was greater in failing than in healthy hearts (P<0.05 each time). Exposure to isocaloric high sugar diet caused significant increases in fatty acid concentrations in healthy and in failing hearts. However, these increases were not associated with any change in the course of cardiac atrophy, similarly in healthy and post-HT(x) failing hearts. We conclude that increasing heart tissue concentrations of the fatty acids allegedly involved in heart growth does not attenuate the unloading-induced cardiac atrophy.

Early morphologic alterations in renal artery wall and renal nerves in response to catheter-based renal denervation procedure in sheep: difference between single-point and multiple-point ablation catheters.

Renal sympathetic hyperactivity is critically involved in hypertension pathophysiology; renal denervation (RDN) presents a novel strategy for treatment of resistant hypertension cases. This study assessed effects of two RDN systems to detect acute intravascular, vascular and peri-vascular changes in the renal artery, and renal nerve alterations, in the sheep. The procedures using a single-point or multi-point ablation catheters, Symplicity Flex(TM), Medtronic versus EnligHTN(TM), St. Jude Medical were compared; the intact contralateral kidneys served as controls. Histopathological and immunohistochemical assessments were performed 48 h after RDN procedures; the kidney and suprarenal gland morphology was also evaluated. Special staining methods were applied for histologic analysis, to adequately score the injury of renal artery and adjacent renal nerves. These were more pronounced in the animals treated with the multi-point compared with the single-point catheter. However, neither RDN procedure led to complete renal nerve ablation. Forty-eight hours after the procedure no significant changes in plasma and renal tissue catecholamines were detected. The morphologic changes elicited by application of both RDN systems appeared to be dependent on individual anatomical variability of renal nerves in the sheep. Similar variability in humans may limit the therapeutic effectiveness of RDN procedures used in patients with resistant hypertension.