Pulmonary artery banding is a surgical procedure performed when there is a shunt between the left and right ventricle. Its aim is to constrict the lumen of the pulmonary artery by using a band to reduce blood flow to the lungs. In this study, we report the results of investigating the mechanical properties of a composite composed of poly(L-lactide-co-ε-caprolactone) layers and a collagen matrix (PLCL-COLL). PLCL layers were obtained by electrospinning, impregnated with collagen solution, and finally cross-linked to increase the stiffness of the material. Bands of PLCL-COLL were implanted into a rat peritoneum and explanted after 1, 3, and 6 months in vivo. The mechanical properties of the material before and after implantation were determined using uniaxial tensile tests. The same was done with samples of strips prepared from GORE-TEX material. By comparing the results of tensile tests before implantation and after explantation, it was found that PLCL-COLL degrades in the rat's body and that it exhibits a mechanical response showing of elastic modulus values that correspond well to arterial biomechanics (elastic modulus measured in the initial linear region of the deformation was found to be: 4.14 MPa ± 1.11 MPa, 2.34 MPa ± 1.02 MPa, 1.11 MPa ± 0.77 MPa, and 0.88 MPa ± 0.60 MPa before implantation, and 1, 3, and 6 months after implantation respectively). Similar to the elastic modulus, the strength of the PLCL-COLL composite decreased during in vivo exposure (1.32 ± 0.32 MPa, 0.60 ± 0.26 MPa, 0.44 ± 0.11 MPa, and 0.46 ± 0.28 MPa before implantation, and 1, 3, and 6 months after implantation respectively). In our experiments, PLCL-COLL material was always more compliant than GORE-TEX (elastic modulus 34.7 MPa ± 2.06 MPa before implantation, and 9.35 MPa ± 6.80 MPa after implantation). The results suggest that PLCL-COLL could be a suitable candidate for the development of artery banding tapes, and also for further use in cardiovascular surgery.
- MeSH
- arteria pulmonalis * chirurgie MeSH
- biokompatibilní materiály chemie MeSH
- biomechanika MeSH
- kolagen * chemie metabolismus MeSH
- krysa rodu rattus MeSH
- mechanické jevy * MeSH
- peritoneum * chirurgie MeSH
- pevnost v tahu MeSH
- polyestery * chemie metabolismus MeSH
- testování materiálů MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- MeSH
- lidé MeSH
- nealkoholová steatóza jater * epidemiologie MeSH
- rizikové faktory MeSH
- zdraví žen MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
The treatment of cartilage defects in trauma injuries and degenerative diseases represents a challenge for orthopedists. Advanced mesenchymal stromal cell (MSC)-based therapies are currently of interest for the repair of damaged cartilage. However, an approved system for MSC delivery and maintenance in the defect is still missing. This study aimed to evaluate the effect of autologous porcine bone marrow MSCs anchored in a commercially available polyglycolic acid-hyaluronan scaffold (Chondrotissue®) using autologous blood plasma-based hydrogel in the repair of osteochondral defects in a large animal model. The osteochondral defects were induced in twenty-four minipigs with terminated skeletal growth. Eight animals were left untreated, eight were treated with Chondrotissue® and eight received Chondrotissue® loaded with MSCs. The animals were terminated 90 days after surgery. Macroscopically, the untreated defects were filled with newly formed tissue to a greater extent than in the other groups. The histological evaluations showed that the defects treated with Chondrotissue® and Chondrotissue® loaded with pBMSCs contained a higher amount of hyaline cartilage and a lower amount of connective tissue, while untreated defects contained a higher amount of connective tissue and a lower amount of hyaline cartilage. In addition, undifferentiated connective tissue was observed at the edges of defects receiving Chondrotissue® loaded with MSCs, which may indicate the extracellular matrix production by transplanted MSCs. The immunological analysis of the blood samples revealed no immune response activation by MSCs application. This study demonstrated the successful and safe immobilization of MSCs in commercially available scaffolds and defect sites for cartilage defect repair.
- MeSH
- hydrogely MeSH
- kloubní chrupavka * chirurgie MeSH
- krevní plazma MeSH
- mezenchymální kmenové buňky * fyziologie MeSH
- miniaturní prasata MeSH
- modely u zvířat MeSH
- prasata MeSH
- tkáňové inženýrství MeSH
- transplantace mezenchymálních kmenových buněk * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Current methods for assessing cell proliferation in 3D scaffolds rely on changes in metabolic activity or total DNA, however, direct quantification of cell number in 3D scaffolds remains a challenge. To address this issue, we developed an unbiased stereology approach that uses systematic-random sampling and thin focal-plane optical sectioning of the scaffolds followed by estimation of total cell number (StereoCount). This approach was validated against an indirect method for measuring the total DNA (DNA content); and the Bürker counting chamber, the current reference method for quantifying cell number. We assessed the total cell number for cell seeding density (cells per unit volume) across four values and compared the methods in terms of accuracy, ease-of-use and time demands. The accuracy of StereoCount markedly outperformed the DNA content for cases with ~ 10,000 and ~ 125,000 cells/scaffold. For cases with ~ 250,000 and ~ 375,000 cells/scaffold both StereoCount and DNA content showed lower accuracy than the Bürker but did not differ from each other. In terms of ease-of-use, there was a strong advantage for the StereoCount due to output in terms of absolute cell numbers along with the possibility for an overview of cell distribution and future use of automation for high throughput analysis. Taking together, the StereoCount method is an efficient approach for direct cell quantification in 3D collagen scaffolds. Its major benefit is that automated StereoCount could accelerate research using 3D scaffolds focused on drug discovery for a wide variety of human diseases.
PURPOSE: Osteoporosis is a severe health problem with social and economic impacts on society. The standard treatment consists of the systemic administration of drugs such as bisphosphonates, with alendronate (ALN) being one of the most common. Nevertheless, complications of systemic administration occur with this drug. Therefore, it is necessary to develop new strategies, such as local administration. METHODS: In this study, emulsion/dispersion scaffolds based on W/O emulsion of PCL and PF68 with ALN, containing hydroxyapatite (HA) nanoparticles as the dispersion phase were prepared using electrospinning. Scaffolds with different release kinetics were tested in vitro on the co-cultures of osteoblasts and osteoclast-like cells, isolated from adult osteoporotic and control rats. Cell viability, proliferation, ALP, TRAP and CA II activity were examined. A scaffold with a gradual release of ALN was tested in vivo in the bone defects of osteoporotic and control rats. RESULTS: The release kinetics were dependent on the scaffold composition and the used system of the poloxamers. The ALN was released from the scaffolds for more than 22 days. The behavior of cells cultured in vitro on scaffolds with different release kinetics was comparable. The difference was evident between cell co-cultures isolated from osteoporotic and control animals. The PCL/HA scaffold show slow degradation in vivo and residual scaffold limited new bone formation inside the defects. Nevertheless, the released ALN supported bone formation in the areas surrounding the residual scaffold. Interestingly, a positive effect of systemic administration of ALN was not proved. CONCLUSION: The prepared scaffolds enabled tunable control release of ALN. The effect of ALN was proved in vitro and in in vivo study supported peri-implant bone formation.
- MeSH
- alendronát * farmakologie MeSH
- emulze farmakologie MeSH
- hydroxyapatit farmakologie MeSH
- inhibitory kostní resorpce * farmakologie MeSH
- krysa rodu rattus MeSH
- osteoblasty MeSH
- osteogeneze MeSH
- osteoklasty MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
INTRODUCTION: Maternal sepsis is a leading cause of maternal and neonatal mortality. Despite the availability of management protocols, there is disparity in case fatality rates for pregnancy-related sepsis compared to other maternity-related complications. The main aim of this systematic review was to assess concordance between international evidence-based guidelines for the prevention and management of childbirth-related bacterial infections. MATERIAL AND METHODS: The PRISMA statement was followed during the conduct and reporting of this review. PubMed was searched electronically from 2009 to November 2019 for clinical guidelines covering the topic of childbirth-related infections and specific searches for relevant guidelines on the websites of the top five international professional bodies most commonly identified by our searches. We did not apply any language restrictions. Guidelines were included if they provided any information about the prevention or management of childbirth-related bacterial infections irrespective of whether the guideline stated a recommendation or not. Two independent reviewers undertook study selection, decisions about inclusion of selected guidelines and data extraction. Extracted information was synthesized under the following topics: Asymptomatic bacteriuria; group B streptococcal infection (GBS); preterm premature rupture of membranes (P-PROM); intrauterine infection; procedures; maternal sepsis; miscellaneous. Concordance was defined as absence of contradictory information between the different guidelines with regards to a specific topic, subtopic or recommendation. Quality of included guidelines was assessed against the AGREE II guideline reporting domains. RESULTS: A total of 43 guidelines were selected of which 11 were excluded leaving 32 guidelines that fulfilled our inclusion criteria. None of the guidelines fulfilled all the quality assessment domains and 11 (34%) of the guidelines satisfied 1-2 of domains only. Two guidelines covered the topic of asymptomatic bacteriuria, nine for GBS, five for P-PROM and three covered each of intra-amniotic infections maternal sepsis, obstetric procedures and interventions topics. The remaining guidelines covered miscellaneous topics. CONCLUSIONS: There was concordance between guidelines with regards to several aspects in the prophylaxis and treatment of bacteriological infections in pregnancy. Nevertheless, there were several areas of discordance, some of which reached the extent of contradictory information as in the case of antenatal screening for GBS.
- MeSH
- antibiotická profylaxe MeSH
- bakteriurie * komplikace MeSH
- infekční komplikace v těhotenství * diagnóza prevence a kontrola MeSH
- lidé MeSH
- novorozenec MeSH
- předčasný odtok plodové vody * mikrobiologie MeSH
- Streptococcus agalactiae MeSH
- streptokokové infekce * diagnóza prevence a kontrola MeSH
- těhotenství MeSH
- Check Tag
- lidé MeSH
- novorozenec MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- systematický přehled MeSH
BACKGROUND/AIM: Patients with unresectable liver colorectal cancer metastases are treated with neoadjuvant chemotherapy often accompanied by biological therapy aimed at reducing the mass of metastases and thus increasing the chances of resectability. Bevacizumab comprises an anti-VEGF (vascular endothelial growth factor) humanized IgG monoclonal antibody that is used for biological therapy purposes. It acts to inhibit angiogenesis, thereby slowing down the growth of metastases. Due to its being administered systematically, bevacizumab also exerts an effect on the surrounding healthy liver parenchyma and potentially limits the process of neovascularization and thus regeneration of the liver. Since the remnant liver volume forms an important factor in postoperative morbidity and mortality following a major hepatectomy, we decided to study the effect of bevacizumab on vascular and biliary microarchitecture in healthy liver parenchyma and its ability to regenerate following major hepatectomy. MATERIALS AND METHODS: We performed an experiment employing a large animal model where a total of 16 piglets were divided into two groups (8 piglets in the control group and 8 piglets in the experimental group with bevacizumab). All the animals were subjected to major hepatectomy and the experimental group was given bevacizumab prior to hepatectomy. All the animals were sacrificed after 4 weeks. We performed biochemical analyses at regular time intervals during the follow-up period. Histological examination of the liver tissue was performed following sacrifice of the animals. RESULTS: No statistical difference was shown between groups in terms of the biochemical and immunohistochemical parameters. The histological examination of the regenerating liver tissue revealed the higher length density of sinusoids in the experimental group. CONCLUSION: Bevacizumab does not act to impair liver regeneration following hepatectomy.
- MeSH
- bevacizumab farmakologie terapeutické užití MeSH
- hepatektomie MeSH
- humanizované monoklonální protilátky farmakologie terapeutické užití MeSH
- kolorektální nádory * farmakoterapie patologie chirurgie MeSH
- lidé MeSH
- modely nemocí na zvířatech MeSH
- nádory jater * farmakoterapie sekundární chirurgie MeSH
- patologická angiogeneze farmakoterapie MeSH
- prasata MeSH
- regenerace jater MeSH
- vaskulární endoteliální růstový faktor A MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Úvod: Kardiovaskulární choroby jsou zodpovědné za významnou morbiditu i mortalitu ve společnosti. Užití umělých cévních materiálů je často nezbytnou součástí v rámci chirurgické léčby, ať již je tato radikální nebo paliativní. V současné době dochází k vývoji řady nových biodegradabilních materiálů určených pro tyto účely. Preklinické testování každého nového materiálu je naprosto nezbytné, je prováděno jak in vitro, tak in vivo. Z tohoto důvodu jsou zvířecí experimentální modely nadále nutnou součástí testování před klinickým užitím. Cílem této práce je prezentovat možnosti užití různých zvířecích modelů na poli kardiovaskulární chirurgie a jejich extrapolace do klinické medicíny. Metody: Autoři prezentují jejich obecné zkušenosti s experimentální chirurgií, na jejich podkladě diskutují optimální výběr zvířecího modelu pro testování nových materiálů pro kardiovaskulární chirurgii a stejně tak optimální lokalitu implantace. Výsledky: Jako optimální experimentální zvířecí modely pro testování hemokompatibility a degradability nových materiálů uvádějí autoři modely potkana, králíka a prasete. Intraperitoneální implantace u potkana je snadná a lehce proveditelná procedura, stejně tak jako arteriální bandáž na aortě králíka či prasete. Rovněž karotické tepny jsou dobře využitelné. Bandáž na prasečí pulmonální tepně je již složitější zákrok s četnějšími komplikacemi. Explantované bandážované cévy po předem definované době jsou vhodné pro další mechanické testování ve smyslu biomechanických analýz, např. inflačně-extenzního testu. Závěr: V posledních fázích preklinického testování nových materiálů se nelze nadále obejít bez in-vivo experimentů. Naší snahou je však striktně dodržovat koncept 3R – Replacement, Reduction a Refinement. V tomto smyslu je třeba využít co nejvíce potenciál každého zvířete tak, abychom mohli redukovat počty zvířat.
Introduction: Cardiovascular diseases are responsible for significant morbidity and mortality in the population. Artificial vascular grafts are often essential for surgical procedures in radical or palliative treatment. Many new biodegradable materials are currently under development. Preclinical testing of each new material is imperative, both in vitro and in vivo, and therefore animal experiments are still a necessary part of the testing process before any clinical use. The aim of this paper is to present the options of using various experimental animal models in the field of cardiovascular surgery including their extrapolation to clinical medicine. Methods: The authors present their general experience in the field of experimental surgery. They discuss the selection process of an optimal experimental animal model to test foreign materials for cardiovascular surgery and of an optimal region for implantation. Results: The authors present rat, rabbit and porcine models as optimal experimental animals for material hemocompatibility and degradability testing. Intraperitoneal implantation in the rat is a simple and feasible procedure, as well as aortic banding in the rabbit or pig. The carotid arteries can also be used, as well. Porcine pulmonary artery banding is slightly more difficult with potential complications. The banded vessels, explanted after a defined time period, are suitable for further mechanical testing using biomechanical analyses, for example, the inflation-extension test. Conclusion: An in vivo experiment cannot be avoided in the last phases of preclinical research of new materials. However, we try to strictly observe the 3R concept – Replacement, Reduction and Refinement; in line with this concept, the potential of each animal should be used as much as possible to reduce the number of animals.
Diabetic foot ulcer (DFU) is a serious complication of diabetes and hyperbaric oxygen therapy (HBOT) is also considered in comprehensive treatment. The evidence supporting the use of HBOT in DFU treatment is controversial. The aim of this work was to introduce a DFU model in ZDF rat by creating a wound on the back of an animal and to investigate the effect of HBOT on the defect by macroscopic evaluation, quantitative histological evaluation of collagen (types I and III), evaluation of angiogenesis and determination of interleukin 6 (IL6) levels in the plasma. The study included 10 rats in the control group (CONT) and 10 in the HBOT group, who underwent HBOT in standard clinical regimen. Histological evaluation was performed on the 18th day after induction of defect. The results show that HBOT did not affect the macroscopic size of the defect nor IL6 plasma levels. A volume fraction of type I collagen was slightly increased by HBOT without reaching statistical significance (1.35+/-0.49 and 1.94+/-0.67 %, CONT and HBOT, respectively). In contrast, the collagen type III volume fraction was ~120 % higher in HBOT wounds (1.41+/-0.81 %) than in CONT ones (0.63+/-0.37 %; p=0.046). In addition, the ratio of the volume fraction of both collagens in the wound ((I+III)w) to the volume fraction of both collagens in the adjacent healthy skin ((I+III)h) was ~65 % higher in rats subjected to HBOT (8.9+/-3.07 vs. 5.38+/-1.86 %, HBOT and CONT, respectively; p=0.028). Vessels density (number per 1 mm2) was found to be higher in CONT vs. HBOT (206.5+/-41.8 and 124+/-28.2, respectively, p<0.001). Our study suggests that HBOT promotes collagen III formation and decreases the number of newly formed vessels at the early phases of healing.
