Goettingen Minipigs Research Articles

The Goettingen minipig as an experimental model in wound-healing studies

BackgroundDeep dermal wounds in extensive burns and chronic wound-healing disorders represent a significant medical problem and require a high level of therapy to reduce the risk of infection and other long-term consequences, such as amputation. A better understanding of the wound-healing processes is essential, and animal models are indispensable to fundamental research. ObjectiveThis study aimed to provide a transparent protocol and prove the effectiveness of an in vivo porcine model using Goettingen minipigs for wound-healing studies. Material and methodsThirteen female Goettingen minipigs were kept in species-appropriate housing and were treated according to the German law for the protection of animals. The study was performed with permission from the local ethical review committee of animal welfare. The experimental procedure for studying dermal regeneration in 102 full-thickness wounds through clinical observation and histological analysis, focusing on neodermal formation, is described in detail. ResultsThe Goettingen minipig model proved to be suitable in wound-healing studies. The dermal regeneration was evident and viewable without wound contamination or any rejection reaction. The histological evaluations were also reliable and clearly presented the optimized wound healing of deep dermal wounds using the different therapeutic approaches. ConclusionGiven the great clinical need for alternative or complementary therapies, we considered the Goettingen minipig trial a reliable, ethically justifiable, effective, and reproducible in vivo model for wound-healing studies.

Clinical characterization of a hypersensitivity mixed bacterial and fungal dermatitis in a translational model of porcine NASH.

The development of animal models of chronic liver disease via diet modification is a promising avenue for translational research but can lead to unexpected side effects that impact model adoption. While these side effects are well characterized in rodent models of nonalcoholic steatohepatitis (NASH), limited knowledge of these effects exists for novel porcine models of NASH. To close this gap, the present study investigates the side effects of diet-based NASH induction in pigs, with a systematic analysis of the pathologic mechanisms underlying dermatitis development and evaluation of treatment approaches. Twelve pigs (10 large domestic pigs, 2 Goettingen minipigs) were fed a methionine- and choline-deficient, high-fat diet for 8 weeks to induce NASH. A retrospective review of each animal's clinical record was performed to identify the side effects of the diet. Following the identification of diet-associated dermatitis, severity was judged by using a novel gradation system that characterized the individual lesions and body regions resulting in a cumulative evaluation. In addition to this clinical assessment, the etiology of the dermatitis was investigated via histopathologic and microbiologic testing. Furthermore, the success of prophylactic and therapeutic treatment approaches was evaluated by considering dermatitis development and clinical course. All study animals demonstrated unexpected side effects of the methionine- and choline-deficient, high fat diet. In addition to marked dermatitis, study pigs showed impaired weight gain and developed steatorrhea and anemia. Based on the skin gradation system, five animals developed severe dermatitis, four animals moderate dermatitis, and three animals mild diet-associated dermatitis. Histological and microbiological evaluation of the affected skin showed signs of a hypersensitivity reaction with secondary infection by bacteria and fungi. The analysis showed that preemptive bathing extended the lesion-free duration by nearly 20 days. Furthermore, bathing in combination with a targeted antibiotic treatment represented a helpful treatment approach for diet-associated dermatitis. The provision of a methionine- and choline-deficient, high fat diet represents an effective approach for inducing NASH liver disease in pigs but predisposes study animals to multiple side effects. These side effects are universal to animals on study but can be adequately managed and do not represent a significant limitation of this model.

Low kV Computed Tomography of Parenchymal Abdominal Organs-A Systematic Animal Study of Different Contrast Media Injection Protocols.

Objectives: To evaluate multiphase low kV computed tomography (CT) imaging of the abdomen with reduced contrast media (CM) dose using different injection protocols. Methods: Two injection protocols were evaluated for use with low kV (80 kV) multiphase abdominal imaging in comparison to the standard procedure acquired at 120 kV (500 mgI/kg; 5 mL/s). This evaluation was conducted in a highly standardized animal study (5 Goettingen minipigs). The low kV protocols consisted of (a) a single-flow (SF) injection with 40% reduced CM dose and injection rate (300 mgI/kg; 3 mL/s) and (b) a DualFlow (DF) injection protocol consisting of 60%/40% contrast to saline ratio administered at 5 mL/s. Dynamic CT was first performed within representative liver regions to determine optimal contrast phases, followed by evaluation of the three protocols in multiphase abdominal CT imaging. The evaluation criteria included contrast enhancement (CE) of abdominal organs and vasculature. Results: The 80 kV DF injection protocol showed similar CE of the abdominal parenchymatous organs and vessels to the 120 kV reference and the 80 kV SF protocol. Hepatic parenchyma showed comparable CT values for all contrast phases. In particular, in the portal venous parenchymal phase, the 80 kV DF protocol demonstrated higher hepatic parenchymal enhancement; however, results were statistically non-significant. Similarly, CE of the kidney, pancreas, and abdominal arterial/venous vessels showed no significant differences between injection protocols. Conclusions: Adapted SF and DF injection protocols with reduced IDR/iodine load offer the potential to calibrate optimal CM doses to the tube voltage in abdominal multiphase low kV CT imaging. The data suggest that the DF approach allows the use of predefined injection protocols and adaption of the contrast to saline ratio to an individualized kV setting and yields the potential for patient-individualized CM adaption.

Long term follow-up of a simplified and less burdened pancreatic duct ligation model of exocrine pancreatic insufficiency in Goettingen Minipigs

BackgroundPancreatic duct ligation in a minipig model leads to exocrine pancreatic insufficiency (EPI). This allows the study of digestive processes and pancreatic enzyme replacement therapies. However, detailed descriptions of the surgical procedure, perioperative management, a determination of exocrine pancreatic insufficiency are scarce in the literature. Data of the long-term health status of minipigs upon EPI induction are still not available. Therefore, the present study describes in detail an experimental approach to the induction of exocrine pancreatic insufficiency via pancreatic duct ligation in minipigs and the long term follow up of the animal’s health state.Methods14 Goettingen minipigs underwent pancreatic duct ligation via midline laparotomy for the induction of exocrine pancreatic insufficiency. Fecal fat content, fat absorption, chymotrypsin levels, body weight and blood vitamin and glucose levels were determined.ResultsExocrine pancreatic insufficiency was successfully induced in 12 Goettingen minipigs. Two minipigs failed to develop exocrine insufficiency most likely due to undetected accessory pancreatic ducts. All animals tolerated the procedure very well and gained weight within 8 weeks after surgery without requiring pancreatic enzyme replacement therapy. The follow up for approx. 180 weeks showed a stable body weight and health state of the animals with normal blood glucose levels (Table 1). From approx. 130 weeks post pancreatic duct ligation, all animals were supplemented with pancreatic enzymes and vitamins resulting in blood concentrations almost within the reference range.ConclusionsPancreatic duct ligation in minipigs is an excellent method of inducing exocrine pancreatic insufficiency. It is important to identify and ligate accessory pancreatic ducts since persistence of accessory ducts will lead to maintenance of exocrine pancreatic function. The EPI model caused no persistent side effects in the animals and has the potential to be used in long-term EPI studies with up to 100 weeks post-OP without supplementation with enzymes and vitamins.

Real-time magnetic resonance imaging \u2013 guided coronary intervention in a porcine model

X-ray fluoroscopy is the gold standard for coronary diagnostics and intervention. Magnetic resonance imaging is a radiation-free alternative to x-ray with excellent soft tissue contrast in arbitrary slice orientation. Here, we assessed real-time MRI-guided coronary interventions from femoral access using newly designed MRI technologies. Six Goettingen minipigs were used to investigate coronary intervention using real-time MRI. Catheters were custom-designed and equipped with an active receive tip-coil to improve visibility and navigation capabilities. Using modified standard clinical 5 F catheters, intubation of the left coronary ostium was successful in all animals. For the purpose of MR-guided coronary interventions, a custom-designed 8 F catheter was used. In spite of the large catheter size, and therefore limited steerability, intubation of the left coronary ostium was successful in 3 of 6 animals within seconds. Thereafter, real-time guided implantation of a non-metallic vascular scaffold into coronary arteries was possible. This study demonstrates that real-time MRI-guided coronary catheterization and intervention via femoral access is possible without the use of any contrast agents or radiation, including placement of non-metallic vascular scaffolds into coronary arteries. Further development, especially in catheter and guidewire technology, will be required to drive forward routine MR-guided coronary interventions as an alternative to x-ray fluoroscopy.

Analysis of porcine body size variation using re-sequencing data of miniature and large pigs

BackgroundDomestication has led to substantial phenotypic and genetic variation in domestic animals. In pigs, the size of so called minipigs differs by one order of magnitude compared to breeds of large body size. We used biallelic SNPs identified from re-sequencing data to compare various publicly available wild and domestic populations against two minipig breeds to gain better understanding of the genetic background of the extensive body size variation. We combined two complementary measures, expected heterozygosity and the composite likelihood ratio test implemented in “SweepFinder”, to identify signatures of selection in Minipigs. We intersected these sweep regions with a measure of differentiation, namely FST, to remove regions of low variation across pigs. An extraordinary large sweep between 52 and 61 Mb on chromosome X was separately analyzed based on SNP-array data of F2 individuals from a cross of Goettingen Minipigs and large pigs.ResultsSelective sweep analysis identified putative sweep regions for growth and subsequent gene annotation provided a comprehensive set of putative candidate genes. A long swept haplotype on chromosome X, descending from the Goettingen Minipig founders was associated with a reduction of adult body length by 3% in F2 cross-breds.ConclusionThe resulting set of genes in putative sweep regions implies that the genetic background of body size variation in pigs is polygenic rather than mono- or oligogenic. Identified genes suggest alterations in metabolic functions and a possible insulin resistance to contribute to miniaturization. A size QTL located within the sweep on chromosome X, with an estimated effect of 3% on body length, is comparable to the largest known in pigs or other species. The androgen receptor AR, previously known to influence pig performance and carcass traits, is the most obvious potential candidate gene within this region.

The impact of injector-based contrast agent administration in time-resolved MRA.

Time-resolved contrast-enhanced MR angiography (4D-MRA), which allows the simultaneous visualization of the vasculature and blood-flow dynamics, is widely used in clinical routine. In this study, the impact of two different contrast agent injection methods on 4D-MRA was examined in a controlled, standardized setting in an animal model. Six anesthetized Goettingen minipigs underwent two identical 4D-MRA examinations at 1.5 T in a single session. The contrast agent (0.1 mmol/kg body weight gadobutrol, followed by 20 ml saline) was injected using either manual injection or an automated injection system. A quantitative comparison of vascular signal enhancement and quantitative renal perfusion analyses were performed. Analysis of signal enhancement revealed higher peak enhancements and shorter time to peak intervals for the automated injection. Significantly different bolus shapes were found: automated injection resulted in a compact first-pass bolus shape clearly separated from the recirculation while manual injection resulted in a disrupted first-pass bolus with two peaks. In the quantitative perfusion analyses, statistically significant differences in plasma flow values were found between the injection methods. The results of both qualitative and quantitative 4D-MRA depend on the contrast agent injection method, with automated injection providing more defined bolus shapes and more standardized examination protocols. • Automated and manual contrast agent injection result in different bolus shapes in 4D-MRA. • Manual injection results in an undefined and interrupted bolus with two peaks. • Automated injection provides more defined bolus shapes. • Automated injection can lead to more standardized examination protocols.

Comparison of contact radiographed and stained histological sections for osseointegration analysis of dental implants: an in vivo study

Histology is still regarded as the gold-standard to determine bone implant contact (BIC) as a parameter representing implant stability. As the further processing of cut slices for contact radiography (CR) to stained and polished histological sections is time consuming and error prone, our aim was to assess agreement between CR and Giemsa-eosin (GE) stained sections with regard to dental implants. Threaded dental titanium implants (n=54) from the maxillae of Goettingen minipigs were evaluated. After 28 and 56days, BIC and the ratio of bone volume to total volume (BV/TV; 1000μm) were determined on the same sections by using CR and GE staining, and the results were compared. Moderate differences for BIC (0.6%; P=.53) and BV/TV (1.3%; P=.01) between the methods were determined, in which CR overestimated BIC and BV/TV. A strong correlation was seen between the modalities concerning BIC (28days: r=0.84; 56days: r=0.85; total: r=0.85) and BV/TV (r=0.96; r=0.94; r=0.96; all: P<.0001). CR enabled determination of the bone-to-implant interface in comparison with GE-stained sections. BIC and BV/TV were slightly overestimated but correlated strongly between the methods. Therefore, if BIC and BV/TV are sufficient endpoints, CR is adequate and no further preparation and staining are necessary.

Production of high-quality islets from goettingen minipigs: Choice of organ preservation solution, donor pool, and optimal cold ischemia time.

The transplantation of porcine islets into man might soon become reality for patients with type 1 diabetes mellitus. Therefore, porcine islets of high quality and quantity, and a scalable isolation process with strict quality control will be an unconditional prerequisite to enable the best possible transplantation graft. In this study, we provide a comparative study evaluating islet isolation outcome and in vitro survival based upon donor age, organ preservation solution (OPS), and cold ischemia time (CIT). Goettingen minipigs of younger age (1year) and retired breeder animals (3.5years) were studied. Pancreata were harvested according to the standards of human organ retrieval including in situ cold perfusion with either Custodiol® -HTK or Belzer® UW solution. Pancreatic tissue was characterized by quantification of apoptotic cells. Islet isolations were performed according to a modified Ricordi method, and isolation outcome was assessed by determining islet particle numbers (IP), islet equivalents (IEQ), and isolation factor (IF). Isolated islets were cultured for 24 and 48h for the assessment of in vitro survival. Islet viability was significantly higher in Custodiol® -HTK preserved pancreas organs compared to Belzer® UW. Furthermore, organs harvested from retired breeder preserved in Custodiol® -HTK resulted in stable islet isolation yields even after prolonged CIT and showed superior survival rates of islets in vitro compared to the Belzer® UW group. Younger porcine donor organs resulted generally in lower islet yield and survival rates. In summary, Custodiol® -HTK solution should be preferred over Belzer® UW solution for the preservation of pancreata from porcine origin. Custodiol® -HTK allows for maintaining islet viability and promotes reproducible isolation outcome and survival even after longer CIT. The usage of retired breeder animals over young animals for islet isolation is highly advisable to yield high quality and quantity.

Diabetes induction by total pancreatectomy in minipigs with simultaneous splenectomy: a feasible approach for advanced diabetes research.

Safe and reliable diabetes models are a key prerequisite for advanced preclinical studies on diabetes. Chemical induction is the standard model of diabetes in rodents and also widely used in large animal models of non-human primates and minipigs. However, uncertain efficacy, the potential of beta-cell regeneration, and relevant side effects are debatable aspects particularly in large animals. Therefore, we aimed to evaluate a surgical approach of total pancreatectomy combined with splenectomy for diabetes induction in an exploratory study in Goettingen minipigs. Total pancreatectomy was performed in Goettingen minipigs (n = 4) under general anesthesia and endotracheal intubation. Prior to surgery, a central venous line was established for drug application and blood sampling. After median laparotomy, splenectomy was performed and the lobular pancreas was carefully dissected with particular attention to the duodenal vascular arcade. Close monitoring of blood glucose was initiated immediately after surgery by standard glucometer measurement or continuous glucose monitoring systems (CGMS). Exogenous insulin was given by multiple daily subcutaneous (s.c.) injections or via insulin pump systems (CSII). Complete endogenous insulin deficiency was confirmed by intravenous glucose tolerance test (ivGTT) and measurement of c-peptide. For establishing a suitable regimen for diabetes management, the animals were followed for 4-6 weeks. Following pancreatectomy and splenectomy, the animals showed a quick recovery from surgery and initial analgetic medication and volume substitution could be terminated within 24 h. A rapid increase in blood glucose was observed immediately following pancreatectomy necessitating insulin therapy. The induced exocrine insufficiency did not cause any clinical symptoms. Complete insulin deficiency could be confirmed in all animals by determination of negative c-peptide during glucose challenge. The two regimen of insulin treatment (multiple daily injections (MDI) and continuous subcutaneous insulin infusion (CSII)) were both feasible with respect to acceptable glycemic control whereas CSII was considerably advantageous in comfort and popularity for both animals and care takers. Surgical pancreatectomy in combination with splenectomy to facilitate access to the pancreas is a feasible model for efficient diabetes induction in minipigs. The procedure itself and postoperative animal care could be performed without complications in this exploratory study. Nevertheless, this approach requires well-equipped infrastructure, experienced and skilled surgeons and anesthesiologists and dedicated animal care takers. The impact of total pancreatectomy in combination with splenectomy on the digestive and immune system must be considered in the design and definition of end points of experimental diabetes and transplantation studies.

Influence of synthetic polyethylene glycol hydrogels on new bone formation during mandibular augmentation procedures in Goettingen minipigs.

Polyethylene glycol hydrogels (PEG) have been used as slow release carrier for osteoinductive growth factors in order to achieve a retarded delivery. However, there have been concerns about negative effects on bone regeneration. This study aims to test whether PEG hydrogels themselves affect new bone formation (NBF), when used as a carrier during mandibular augmentation procedures. In a randomized split-mouth design, bilateral mandibular bone defects were surgically created in 12 Goettingen minipigs, and subsequently augmented, using PEG hydrogel on one side of the mandible. The contralateral sides, without PEG, served as controls. After 4 and 12 weeks, bone formation was evaluated in six animals each. A comparison of the data, using a three-way analysis of variance (ANOVA), revealed a significant effect of the healing time and the region of the graft on the distribution and enhancement of NBF (P < .0001, respectively). Although a 0.3% (95%-CI [-5.5; 4.8]) lower volume density of newly formed bone could be observed over all PEG hydrogel sections, in contrast to the contralateral controls, the analysis revealed no clinically significant effects of the PEG hydrogel treatment on the total level (P = 0.90), and the distribution of NBF (P = 0.54). In conclusion, PEG hydrogels do not affect NBF when used as a carrier for osteoinductive growth factors during mandibular augmentation procedures.

Pulmonary vein isolation by radiosurgery: implications for non-invasive treatment of atrial fibrillation.

Electrical isolation of the pulmonary veins (PVs) has been established in clinical routine as a curative treatment for atrial fibrillation (AF). While catheter ablation carries procedural risks, radiosurgery might be able to non-invasively induce lesions at the PV ostia to block veno-atrial electrical conduction. This porcine feasibility and dose escalation study determined the effect of radiosurgery on electrophysiologic properties of the left atrial-PV junction. Eight adult Goettingen mini-pigs underwent electrophysiological voltage mapping in the left atrium and the upper right PV. Radiation was delivered with a conventional linear accelerator. A single homogeneous dose ranging from 22.5 to 40 Gy was applied circumferentially to the target vein antrum. Six months after radiosurgery, electrophysiological mapping was repeated and a histological examination performed. Voltage mapping consistently showed electrical potentials in the upper right PV at baseline. Pacing the target vein prompted atrial excitation, thus proving veno-atrial electrical conduction. After 6 months, radiation had reduced PV electrogram amplitudes. This was dose dependent with a mean interaction effect of -5.8%/Gy. Complete block of atrio-venous electrical conduction occurred after 40 Gy dose application. Histology revealed transmural scarring of the targeted PV musculature with doses >30 Gy. After 40 Gy, it spanned the entire circumference in accordance with pulmonary vein isolation. Pulmonary vein isolation to treat AF can be achieved by radiosurgery with a conventional linear accelerator. Yet, it requires a high radiation dose which might limit clinical applicability.

Prevention of foreign body reaction in a pre-clinical large animal model

In this work, the foreign body reaction (FBR) to small subcutaneous implants was compared between small (rodent) and large (swine) animal species for the first time. Dexamethasone-releasing poly(lactic-co-glycolic acid) microspheres/polyvinyl alcohol hydrogel composite coatings were adapted to prevent FBR to small, subcutaneous implants in a large animal model (Goettingen minipigs). The implants consisted of small silicon chips (used to mimic small medical devices) that were coated with the composite formulations. The stages of the FBR were compared with previous studies in rats (that used the same-sized implants); the onset and severity of chronic inflammation (collagen deposition) was identified as a key difference between the two species. In the absence of inflammation control, fibrosis was observed from day 7 post-implantation in minipigs, whereas in rats this did not occur until day 14. This is significant as swine skin is the most commonly used model for preclinical testing of dermal formulations. It was determined that for long-term prevention of the FBR (longer than 24h), a lag phase in dexamethasone release between days 1 and 10 did not affect the anti-FBR properties of the implant in rats. However, continuous release of dexamethasone, with no lag phase, was necessary to prevent inflammation in minipigs (effective dexamethasone dose was 100μg delivered immediately after implantation and 10μg/day delivered continuously thereafter). This study offers significant insight into the translation of anti-FBR strategies across species, and showcases the importance of tailoring the controlled release kinetics of the formulation to the host response.

Concentration of platelets and growth factors in platelet-rich plasma from Goettingen minipigs.

In minipigs little is known about the concentration of growth factors in plasma, despite their major role in several patho-physiological processes such as healing of fractures. This prompted us to study the concentration of platelets and selected growth factors in plasma and platelet-rich plasma (PRP) preparation of sixteen Goettingen minipigs. Platelet concentrations increased significantly in PRP in comparison to native blood plasma. Generally, significant increase in the concentration of all growth factors tested was observed in the PRP in comparison to the corresponding plasma or serum. Five of the plasma samples examined contained detectable levels of bone morphogenic protein 2 (BMP-2) whereas eleven of the plasma or serum samples contained minimal amounts of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF-bb) respectively. On the other hand variable concentrations of bone morphogenic protein 7 (BMP-7) and transforming growth factor β1 (TGF-β1) were measured in all plasma samples. In contrast, all PRP samples contained significantly increased amounts of growth factors. The level of BMP-2, BMP-7, TGF-β1, VEGF and PDGF-bb increased by 17.6, 1.5, 7.1, 7.2 and 103.3 fold, in comparison to the corresponding non-enriched preparations. Moreover significant positive correlations were found between platelet count and the concentrations of BMP-2 (r=0.62, p<0.001), TGF-β1 (r=0.85, p<0.001), VEGF (r=0.46, p<0.01) and PDGF-bb (r=0.9, p<0.001). Our results demonstrate that selected growth factors are present in the platelet-rich plasma of minipigs which might thus serve as a source of autologous growth factors.

Increase of homogenous new bone formation using osteoinductive factor rhGDF-5 during sinus floor augmentation in Goettingen Minipigs.

The aim of this study was to test the hypothesis that recombinant human growth and differentiation factor-5 (rhGDF-5) induces an increased and homogenous distribution of new bone formation across the entire volume of sinus floor augmentation in 12 Goettingen Minipigs. In a randomized split-mouth design, one maxillary sinus was augmented with the bone substitute β-TCP, whereas a combination of β-TCP and the osteoinductive growth factor rhGDF-5 was used on the contralateral side. To evaluate the influence of dose and time on the effectiveness of the factor, two different concentrations of rhGDF-5 (400 μg and 800 μg) and healing periods (4 and 12 weeks) were each analysed. After 4 weeks, a homogenous gradient of bone formation could be observed for all dosage groups, with decreasing bone density from the local bone towards the sinus membrane. Both test groups, however, achieved a higher total level of bone formation compared with the control group, which was only significant in the low-dose group (P = 0.0184). After 12 weeks, the influence of the growth factor significantly depends on the region (P = 0.023). In the low-dose group, the new bone formation did not differ significantly within the examined regions of the graft (P = 0.1118), suggesting a homogeneous bone formation over the entire augmentation. The gradient of the high-dose group was similar to the control group with a decrease of local bone development. rhGDF-5 delivered on a β-TCP scaffold material leads to an increase in homogeneous new bone formation across the entire volume of the sinus floor augmentation.

Intraindividual Quantitative and Qualitative Comparison of Gadopentetate Dimeglumine and Gadobutrol in Time-Resolved Contrast-Enhanced 4-Dimensional Magnetic Resonance Angiography in Minipigs

The concentration and relaxivities of contrast agents affect quantitative and qualitative image quality in contrast-enhanced time-resolved 4-dimensional magnetic resonance angiography (4D-MRA). Gadobutrol has a high relaxivity and is the only gadolinium (Gd)-based contrast agent approved for clinical use at a 1 M concentration. This promises to confer superior bolus characteristics by generating a steeper and shorter bolus with a higher peak Gd concentration. The purpose of this study was to quantitatively examine bolus characteristics of 1 M gadobutrol compared with 0.5 M gadopentetate dimeglumine and to evaluate image quality in thoracoabdominal 4D-MRA. A total of 7 Goettingen minipigs received dynamic computed tomography (CT) on a clinical 64-slice CT (transverse slices, 80 kV, 20 seconds, 0.3 s/dynamic frame) and 4D-MRA (time-resolved imaging with stochastic trajectories; 1. transverse slices, 30 seconds, 0.49 s/frame; 2. coronal slices, 70 seconds, 1.3 s/frame) on a 1.5-T clinical whole-body magnetic resonance imaging under general anesthesia using gadopentetate dimeglumine and gadobutrol in an intraindividual comparative study. Computed tomography attenuations were converted into Gd concentrations on the basis of previous phantom experiments. Quantitative analysis included measurements of the full width at half maximum, time-to-peak intervals, and peak of each bolus in dynamic CT and transverse 4D-MRA. These studies were carried out at equivalent contrast agent flow rates of 1 mL/s. Quantitative analysis (7 arteries and veins) and qualitative image analysis were performed on coronal thoracoabdominal 4D-MRA studies carried out at flow rates of 1 mL/s and, in the case of gadopentetate dimeglumine, also at molarity-adjusted flow rates of 2 mL/s. The bolus in both transverse 4D-MRA and dynamic CT was significantly narrower (full width at half maximum), earlier (time to peak), and higher (signal intensity enhancement in 4D-MRA, Gd concentration in dynamic CT) when using gadobutrol instead of gadopentetate dimeglumine at a flow rate of 1.0 mL/s (P = 0.008-< 0.0001). In thoracoabdominal 4D-MRA, the signal intensity level and overall image quality were highest in examinations with gadobutrol, followed by examinations with gadopentetate dimeglumine at flow rates of 2 mL/s, and lowest in examinations with gadopentetate dimeglumine at flow rates of 1 mL/s. A more compact bolus shape was observed after administration of gadobutrol compared with gadopentetate dimeglumine in minipigs. This was demonstrated both in 4D-MRA, where Gd concentration, relaxivity, and the image-acquisition technique play a role, and in CT, where the signal intensity depends only on the Gd concentration. The overall image quality was rated higher in examinations with 1.0 M gadobutrol than with 0.5 M gadopentetate dimeglumine.

Assessment of microcirculatory changes of cold contact injuries in a swine model using laser Doppler flowmetry and tissue spectrophotometry

BackgroundUntil now, the exact pathophysiology of frostbite injuries is poorly understood. The aim of the study is to evaluate the perfusion changes of frostbite injuries to get a better understanding of the exact mechanism underlying the resulting tissue damage. Particular attention has been given to the differentiation of changes between the various injury depths. MethodsCold contact injury ranging from superficial, superficial-partial, deep-partial to full thickness were generated using seven goettingen minipigs. The perfusion dynamics were assessed before and 3h after the injuries were inflicted using the O2C-device, which combines a laser light, to determine blood flow, and white light to determine hemoglobin oxygenation and relative amount of hemoglobin. A total of 42 cold contact injuries were inflicted and 84 measurements were carried out. ResultsIn superficial and superficial partial injuries there was an increase in the blood flow (mean, 20±2.4%, 15±5.1%, respectively) and in the relative amount of hemoglobin (mean, 29±9.1%, 28±7.2%, respectively), whereas the hemoglobin oxygenation did not alter (mean, −0.15±2.4%, −0.8±3.1%, respectively). In deep partial injuries there was a decrease in the blood flow (mean range, −4±2.1 to −17±4.7%) and an increase in the relative amount of hemoglobin (mean range, 79±17.2 to 93±17.7%), whereas the hemoglobin oxygenation did not alter (mean range, −0.7±3.1 to −2.9±3.3%). In full thickness injuries there was a drop in the blood flow (mean range, −24±7.6 to −27±11.8%) and in the hemoglobin oxygenation (mean range, −16±3.5 to −19±2.5%) and an increase in the relative amount of hemoglobin (mean range, +126±19.8 to 145±10.9%). ConclusionThe results of this study form a more precise pattern of cold contact injury perfusion changes, which can be a valuable tool to assess the degree of cold contact injury and furthermore the efficacy of novel diagnostic aids, therapeutics and treatment modalities.

35 CHARACTERIZATION OF URINARY BLADDER FUNCTION IN GOETTINGEN MINIPIGS (GM) MONITORED BY RADIOTELEMETRIC NATURAL FILLING CYSTOMETRY (CM): NON-MICTURITION-ASSOCIATED (NM) AND MICTURITION-ASSOCIATED (MI) DETRUSOR EVENTS

You have accessJournal of UrologyUrodynamics/Incontinence/Female Urology: Basic Research (1)1 Apr 201335 CHARACTERIZATION OF URINARY BLADDER FUNCTION IN GOETTINGEN MINIPIGS (GM) MONITORED BY RADIOTELEMETRIC NATURAL FILLING CYSTOMETRY (CM): NON-MICTURITION-ASSOCIATED (NM) AND MICTURITION-ASSOCIATED (MI) DETRUSOR EVENTS Nadine D. Huppertz, Carmen Fera, Dorothea Leonhäuser, Katja Strick, Isabella Zraik, Sarah Hirshman, Ulrich Schwantes, Ruth Kirschner-Hermanns, and Joachim O. Grosse Nadine D. HuppertzNadine D. Huppertz Aachen, Germany More articles by this author , Carmen FeraCarmen Fera Aachen, Germany More articles by this author , Dorothea LeonhäuserDorothea Leonhäuser Aachen, Germany More articles by this author , Katja StrickKatja Strick Aachen, Germany More articles by this author , Isabella ZraikIsabella Zraik Aachen, Germany More articles by this author , Sarah HirshmanSarah Hirshman Aachen, Germany More articles by this author , Ulrich SchwantesUlrich Schwantes Hallstadt, Germany More articles by this author , Ruth Kirschner-HermannsRuth Kirschner-Hermanns Bonn, Germany More articles by this author , and Joachim O. GrosseJoachim O. Grosse Aachen, Germany More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.1410AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Radiotelemetric CM is a very useful tool to investigate and monitor detrusor function for large animal models in a longterm setting. Telemetric transmitter devices (TTD, DSI: St. Paul, Minnesota) provides high quality of cystometric parameters like pressure (DDmax), duration of detrusor contraction (DoC) and frequency of detrusor events (FD). To characterize detrusor and bladder function during filling and voiding phase micturition- (MI) and non-micturition-associated detrusor events (NM) were collected and analyzed by CM via video camera (VC) and flowmetry (FM) in five female GM. METHODS The TTD were implanted, pressure-sensory catheters were placed and fixed into the bladder and peritoneum. Transmitted 24 h recordings were obtained in a metabolic cage within 6 six weeks. The investigated parameters (DDmax, Doc, FD) were analyzed for each GM and then summarized for the respective parameters. For calculation of the quotient of NM divided by MI, we differentiated those detrusor events with VC and FM analyses. RESULTS High quality CM were obtained in both cases at baseline and on follow-up, less than 8.5 % of radiotelemetric events could not be assigned to MI or NM. For all GM the mean MI-frequency was 6.4 per day (range: 2.4-10.4 with n≥18 MI). Corresponding DDmax and duration of detrusor contraction (DoC) were 52.0 mmHg (range: 23.5-81.8 mmHg with n=2-20 NM) and 82.0 sec. (range: 8-200 sec.). NM/MI-quotient of pig1 was 0.77 while for pig2, pig3, pig4 and pig5 the quotient was 0.11, 0.3, 0.09 and 0.33. The filling phase in natural bladders is characterized by rare NM, which is an indicator for detrusor stability. CONCLUSIONS Radio-telemetry provides a high quality real-time natural filling CM monitoring. The NM/MI-quotient can function as a parameter which is independent from metabolic cage associated parameters and can be applied to determine detrusor stability. It could therefore be a suitable indicator in other models of bladder disorders. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e14 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Nadine D. Huppertz Aachen, Germany More articles by this author Carmen Fera Aachen, Germany More articles by this author Dorothea Leonhäuser Aachen, Germany More articles by this author Katja Strick Aachen, Germany More articles by this author Isabella Zraik Aachen, Germany More articles by this author Sarah Hirshman Aachen, Germany More articles by this author Ulrich Schwantes Hallstadt, Germany More articles by this author Ruth Kirschner-Hermanns Bonn, Germany More articles by this author Joachim O. Grosse Aachen, Germany More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Treatment of Reperfused Ischemia with Adipose-Derived Stem Cells in a Preclinical Swine Model of Myocardial Infarction

The aim of the study was to determine the long-term effect of transplantation of adipose-derived stromal cells (ADSCs) in a preclinical model of ischemia/reperfusion (I/R). I/R was induced in 28 Goettingen minipigs by 120 min of coronary artery occlusion followed by reperfusion. Nine days later, surviving animals were allocated to receive transendocardial injection of a mean of 213.6 ± 41.78 million green fluorescent protein (GFP)-expressing ADSCs (n = 7) or culture medium as control (n = 9). Heart function, cell engraftment, and histological analysis were performed 3 months after transplantation. Transplantation of ADSCs induced a statistically significant long-lasting (3 months) improvement in cardiac function and geometry in comparison with control animals. Functional improvement was associated with an increase in angiogenesis and vasculogenesis and a positive effect on heart remodeling with a decrease in fibrosis and cardiac hypertrophy in animals treated with ADSCs. Despite the lack of cell engraftment after 3 months, ADSC transplantation induced changes in the ratio between MMP/TIMP. Our results indicate that transplantation of ADSCs, despite the lack of long-term significant cell engraftment, increases vessel density and prevents adverse remodeling in a clinically relevant model of myocardial infarction, strongly suggesting a paracrine-mediated effect. ADSCs thus constitute an attractive candidate for the treatment of myocardial infarction.

Surgical Soft Tissue Trauma Can Cause Disk Degeneration—An in Vivo Animal Study on Goettingen Minipigs

Introduction Biological treatment options, such as disk-cell-therapy, have been proposed for only moderately degenerated disks. Therefore, surgical exposition of the disk is needed. However, the effect of surgery related soft-tissue damage on the maintenance of disk degeneration is poorly understood. Therefore, this study analyzes, if disk degeneration can be induced only by the surgical approach. Materials and Methods We used an established model with adult minipigs offering biomechanical properties similar to humans. Total 12 animals underwent surgery using an anterolateral retroperitoneal approach to the lumbar spine. At each animal, two disks were only exposed whereas two other disks were exposed and partially nucleotomized with a 16G-biopsy-needle. Animals received a second revision surgery after 12 weeks, using the same approach and all disks were exposed again. Total 13 or 24 weeks after first surgery, animals were sacrificed. Disk height was measured in the central part of the disk by micro-CT. Disk degeneration was evaluated by a semiquantitative histo-degeneration-score. Three untreated control animals served as controls. Results After the second surgery, increased scar tissue and less vascularization was found around the lumbar vertebral bodies on the side of the approach. Most degenerative changes were found after partial nucleotomy ( p &lt; 0.05) and additional annular damage was detectable, with a trend to higher degeneration scores after 24 weeks; disk height was significantly reduced compared to all other groups ( p &lt; 0.05; 3.2 and 3.3 mm). Disks that were only surgically exposed also revealed significant degenerative changes including increased osteophytes; disk height was also significantly reduced compared to healthy control disks from animals without surgery ( p &lt; 0.05; 3.7 and 3.8 mm vs. 4.6 mm). Conclusion Surgical exposure of lumbar disks caused significant disk degeneration without further disk manipulations. Reduced nutrient supply to the disk caused by less vascularized scar tissue seems to be a reason, which will be analyzed by additional immunohistological stainings against CD31. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared