Porcine Small Intestine Research Articles

Extracellular matrix graft for vascular reconstructive surgery: evidence of autologous regeneration of the neoaorta in a murine model

The study aimed to evaluate the efficacy of the porcine small intestine submucosa extracellular matrix (SIS-ECM) in a murine model, as a possible vascular patch for clinical use in reconstructive vascular and potentially cardiac surgery. Fifteen adult male Sprague Dawley rats and five green fluorescent protein (GFP) rats were enrolled in this study. The SIS-ECM graft (6 mm long, 4 mm wide) was implanted for patch plasty on the abdominal aorta of the animal, after excising part of its anterior wall. Histology and immunohistochemistry were used to evaluate the results at 15, 30, 90 and 180 days post-surgery. Graft re-population was demonstrated 15 days after implantation. The luminal surface of the regenerating tissue was partially covered by endothelial cells, and intimal hyperplasia occurred in the central part of the graft. Complete re-endothelialization of the patch with smooth muscle cells colonizing the graft and acting as the neoaortic wall was observed after 30 days. Near complete absorption of the biomaterial was observed after 180 days. No inflammatory cell reaction occurred. All animals survived and no graft aneurysm was observed. A SIS-ECM patch allowed the colonization of host endothelial and smooth muscle cells in the graft. This material may be an ideal substitute for reconstructive vascular surgery, and its use could be extended to surgical repair of cardiac defects.

Reconstruction of pulmonary artery with porcine small intestinal submucosa in a lamb surgical model: Viability and growth potential

This study investigated the time-dependent remodeling and growth potential of porcine small intestine submucosa as a biomaterial for the reconstruction of pulmonary arteries in a lamb model. Left pulmonary arteries were partially replaced with small intestine submucosal biomaterial in 6 lambs. Two animals each were humanely killed at 1, 3, and 6 months. Computed tomographic angiography, macroscopic examination of the implanted patch, and microscopic analysis of tissue explants were performed. All animals survived without complications. Patency and arborization of the pulmonary arteries were detected 6 months after implantation. There was no macroscopic narrowing or aneurysm formation in the patch area. The luminal appearance of the patch was similar to the intimal layer of the adjacent native pulmonary artery. Scanning electron microscopy showed that the luminal surface of the patch was covered by confluent cells. Immunohistochemical examination confirmed endothelialization of the luminal side of the patch in all of the explanted patches. The presence of smooth muscle cells in the medial layer was confirmed at all time points; however, expression of elastin, growth of the muscular layer, and complete degradation of patch material were detectable only after 6 months. The presence of c-Kit-positive cells suggests migration of multipotent cells into the patch, which may play a role in remodeling the small intestine submucosal biomaterial. Our data confirmed that remodeling and growth potential of the small intestine submucosal biomaterial are time dependent. Additional experiments are required to investigate the stability of the patch material over a longer period.

Effects of deoxynivalenol and lipopolysaccharide on electrophysiological parameters in growing pigs

Deoxynivalenol (DON) is a major B-trichothecene that draws importance from its natural occurrence in cereals worldwide. It has many effects on rapidly dividing cells. Lipopolysaccharide (LPS) is an endotoxin released from most Gram-negative bacteria, which plays a major role in induction of inflammation and sepsis under certain conditions. In our experiments we aimed to study the effects of different concentrations of DON (up to 8,000ng/ml) on the electrogenic transport of nutrients and on tissue conductances in growing pigs using the Ussing chamber technique. The effect of DON-contaminated feed (2.9mg/kg feed) on the respective parameters, as well as the interactions between DON and intraperitoneal (i.p.) LPS were assessed using porcine jejunal tissues. In vitro DON inhibited the absorption of alanine and glucose across the pig jejunum at concentrations of 4,000 and 8,000ng/ml, suggesting that DON had an inhibitory effect on the electrogenic transport of nutrients across porcine small intestines. Electrogenic transport of alanine and glucose across porcine small intestines varied regionally among intestinal segments with higher response in ileal tissues. A synergistic effect was observed between DON in feed and injected LPS on tissue conductance. In response, glucose with higher short circuit currents was observed across porcine jejunal mucosa in nutrient stimulated conditions.

Effect of Robotic Manipulation on Unidirectional Barbed Suture Integrity: Evaluation of Tensile Strength and Sliding Force

One of the more challenging portions of robot-assisted radical prostatectomy (RARP) is the urethrovesical anastomosis. Because of this, a unidirectional absorbable barbed suture (V-Loc(™)) has been used to complete the anastomosis with better efficiency and less tension. The effect of robotic needle driver manipulation on barbed suture is unknown. Therefore, the aim of this study is to determine whether robotic manipulation decreases the tensile strength and peak sliding force of V-Loc barbed suture. Fifty-six V-Loc sutures were compared with 56 Maxon sutures. All sutures were 3-0 caliber. Half of the sutures in each group were manipulated with a da Vinci(®) robot large needle driver five times over a 5 cm length of suture. The other half was not manipulated. Breaking force was determined by placing sutures in a Bose ElectroForce load testing device. For sliding force testing, 28 V-Loc sutures were manipulated in the same fashion and compared with 28 nonmanipulated V-Loc sutures. Peak force needed to make the suture slip backward in porcine small intestine was determined to be the sliding force. Scanning electron microscopy of the barbs before and after robotic manipulation was also performed. The mean difference in breaking forces for manipulated vs nonmanipulated Maxon sutures was 4.52 N (P=0.004). The mean difference in breaking forces for manipulated vs nonmanipulated V-Loc sutures was 1.30 N (P=0.046). The manipulated V-Loc group demonstrated a lower peak sliding force compared with the nonmanipulated group (0.76 vs 0.88 N, P=0.199). Electron microscopy revealed minor structural damage to the barbs and suture. Tensile strength and peak sliding force of V-Loc suture is decreased by robotic manipulation. This is likely because of structural damage to the suture and barbs. This structural damage, however, is likely not clinically significant.

Effect of enzymatic degradation on the mechanical properties of biological scaffold materials

Biological scaffolds must support a complex balance of resisting enzymatic degradation while promoting tissue remodeling. Thus, the purpose of this study was to evaluate the effects of in vitro enzymatic exposure on the mechanical properties of biological scaffolds. It was hypothesized that exposure to an enzyme solution would result in decreased tensile strength and that crosslinked scaffolds would resist enzymatic degradation more effectively than noncrosslinked scaffolds. Nine scaffolds were evaluated (four porcine dermis: Permacol™, CollaMend™, Strattice™, XenMatrix™; two human dermis: AlloMax™, FlexHD(®); two bovine pericardium: Veritas(®), PeriGuard(®); and one porcine small intestine submucosa: Surgisis™). Ten specimens (n = 10) were hydrated in saline at 37 °C and subjected to uniaxial testing to establish baseline properties. 50 specimens (n = 50) were incubated in collagenase solution at 37 °C for 2, 6, 12, 24, or 30 h (n = 10 each group) followed by uniaxial tensile testing. Tensile strength was significantly reduced after 30 h for CollaMend™, AlloMax™, Veritas(®), Strattice™, XenMatrix™, Permacol™, and FlexHD(®) (p < 0.01), while PeriGuard(®) demonstrated a slight increase in tensile strength (p = 0.0188). Crosslinked bovine pericardium (PeriGuard(®)) maintained greater tensile strength than noncrosslinked bovine pericardium (Veritas(®)) throughout all exposure periods (p < 0.0001). Similarly, crosslinked porcine dermis (Permacol™) maintained greater tensile strength than noncrosslinked porcine dermis (Strattice™ and XenMatrix™) throughout all exposure periods (p < 0.0001). Materials that deteriorate rapidly after in vitro enzymatic exposure may also deteriorate rapidly in vivo, particularly when exposed to a wound environment with elevated levels of matrix metalloproteinases. Permacol™, CollaMend™, Strattice™, FlexHD(®), and PeriGuard(®) survived the longest incubation period (30 h) and withstood mechanical testing. XenMatrix™, AlloMax™, Veritas(®), and Surgisis™ degraded more quickly and did not survive the longer exposure periods. Scaffolds that maintain strength characteristics after in vitro collagenase exposure may be advantageous for long-term hernia repair scenarios where elevated enzyme levels are expected.

Effect of Repetitive Loading on the Mechanical Properties of Biological Scaffold Materials

Coughing, bending, and lifting raise the pressure inside the abdomen, repetitively increasing stresses on the abdominal wall and the associated scaffold. The purpose of this study was to evaluate the effect of repetitive loading on biological scaffolds. It was hypothesized that exposure to repetitive loading would result in decreased tensile strength and that crosslinked scaffolds would resist these effects more effectively than non-crosslinked scaffolds. Nine materials were evaluated (porcine dermis: Permacol, CollaMend, Strattice, XenMatrix; human dermis: AlloMax, FlexHD; bovine pericardium: Veritas, PeriGuard; and porcine small intestine submucosa: Surgisis; in addition, Permacol, CollaMend, and PeriGuard are crosslinked). Ten specimens were hydrated and subjected to uniaxial tension to establish baseline properties. Thirty specimens were hydrated and subjected to 10, 100, or 1,000 loading cycles (n = 10 each). Tensile strength remained unchanged for CollaMend, XenMatrix, Veritas, and Surgisis during all cycles (p > 0.05). However, Strattice and AlloMax exhibited reduced tensile strength, and Permacol, FlexHD, and PeriGuard exhibited a slight increase in tensile strength with increasing number of cycles. Crosslinked bovine pericardium (PeriGuard) displayed greater tensile strength than non-crosslinked bovine pericardium (Veritas) and crosslinked porcine dermis (Permacol) exhibited greater tensile strength than non-crosslinked porcine dermis (Strattice, XenMatrix) during all cycles (p < 0.0001). Materials that rapidly lose strength after repetitive loading might not be appropriate in clinical scenarios involving elevated stresses, such as in patients with high body mass index or when replacing large areas of the abdominal wall without tissue reinforcement, although scaffolds that maintain initial tensile strength can be particularly advantageous.

Old Age is a Risk Factor for Recurrence after Laparoscopic Inguinal Hernia Repair with Porcine Small Intestine Submucosa Mesh

Old Age is a Risk Factor for Recurrence after Laparoscopic Inguinal Hernia Repair with Porcine Small Intestine Submucosa Mesh

Abstract No. 9: Improved bioprosthetic valve for the treatment of chronic deep venous insufficiency using an autologous endothelial layer

Percutaneous transcatheter implantation of porcine small intestine submucosa (SIS) tissue valves has been investigated and previously reported as a treatment to improve symptoms of chronic deep venous insufficiency (CDVI). Endothelial progenitor outgrowth cells (EOCs), isolated from whole ovine blood, were evaluated in vitro and in an ex vivo flow loop as a source of autologous seeding for SIS endothelialization. 20 bioprosthetic venous valves (BVVs) were constructed from SIS sutured onto collapsible square stent frames. Cell seeding of ovine EOCs in vitro was optimized and endothelialization was evaluated by immunofluorescent staining. Retention of the endothelial layer through BVV loading and delivery (3 valves), in vitro flow (3), and ex vivo flow (4) was evaluated with immunofluorescent staining and histology. In the ex vivo shunt loop, venous blood was pulled from an implanted dialysis catheter, through the BVV, and returned to the sheep. Immunofluorescent staining of the EOCs on the BVVs after in vitro seeding (optimized at seeding density: 9×105 cells/cm2) revealed a confluent monolayer on each side of the valve. When examined by immunofluorescent staining and histology, the endothelial layer remained intact after loading and delivery and when subjected to flow in the in vitro loop. Histology of the BVV subjected to the ex vivo shunt loop revealed retention of the endothelial layer. Endothelial layers seeded on SIS were retained under loading and delivery, in vitro flow and ex vivo flow. EOCs are a promising cell source for autologous endothelialization of bioprosthetic valves for the treatment of CDVI.

Tracheal reconstruction by mesenchymal stem cells with small intestine submucosa in rabbits

AimThe increasing number of newborns requiring intubation and artificial ventilation in the sophisticated premature and intensive care units of recent years has been followed by a concomitant increase in the number of children who develop tracheal stenosis as a sequela of prolonged intubation, with a consequent increasing need for tracheal surgical repair. The aim of this study was to evaluate tracheal reconstruction by monolayered autologous mesenchymal stem cells (MSCs) with small intestine submucosa (SIS) in a rabbit model. MethodsTwelve male rabbits were randomly divided into three groups: rabbits with tracheal defects without reconstruction (untreated group, n=4), rabbits with tracheal defects given porcine small intestine submucosa graft (SIS group, n=4), and rabbits with tracheal defects that underwent transplantation of monolayered mesenchymal stem cells on SIS (SIS+MSC group, n=4). Histological and endoscopic analyses were performed by hematoxylin–eosin staining (H&E), Prussian blue staining and endoscopy. ResultsTracheal stenosis in the SIS+MSC group was minimal, compared to the untreated group and SIS group. Specimens obtained from the untreated and SIS groups showed severe infiltration of inflammatory cells and granulation tissue formation into the trachea. In the SIS+MSC group, however, minimal infiltration of the inflammatory cells and granulation tissue formation were observed. Twelve weeks following the operation, regeneration of pseudostratified columnar epithelium was confirmed by H&E staining with minimal inflammatory cell infiltration in the SIS+MSC group. Moreover, Prussian blue staining clearly demonstrated the presence of labeled MSCs in the regenerated tissue of SIS+MSC group. ConclusionsThese results demonstrate that tracheal reconstruction by MSCs with SIS is effective in rabbits with tracheal defects with minimal mortality and morbidity, which appears to be a promising strategy in the treatment of tracheal defects.

Biological Resurfacing for Early Osteoarthritis of the Shoulder

Young patients with degenerative shoulder disease are a therapeutic challenge. To try to delay a shoulder arthroplasty, biological interpositional arthroplasty has been proposed to provide a biologically active bearing surface that could eventually results in the formation of fibrocartilage, fibrous tissue, or hyaline cartilage. Anterior capsule, autogenous fascia lata, Achilles tendon allograft, lateral meniscus allograft, human dermis, and porcine small intestine submucosa have been used as interposition material, either alone or in combination with a hemiarthroplasty or humeral resurfacing procedure. Some investigators have reported favorable long-term results, although others have found this procedure unreliable. Several variables are unknown at present, such as the best biological resurfacing device, healing potential, possible antigenic responses, optimal fixation technique or position, aftercare restrictions. Further prospective studies with long follow-up are necessary to provide data that will help to define the role of biological glenoid resurfacing in young patients with glenohumeral arthritis.

Histologic and Biomechanical Evaluation of Biologic Meshes following Colonization with Pseudomonas aeruginosa

Biologic meshes have become increasingly popular for the repair of abdominal wall defects, especially in contaminated sites. The purpose of this study was to evaluate the histologic and biomechanical properties of biologic mesh in response to a bacterial encounter. A rat model of Pseudomonas aeruginosa colonization and infection of subcutaneously implanted biologic mesh was used. Samples of biologic meshes [acellular human dermis (ADM) and porcine small intestine submucosa (SIS)] were inoculated with P. aeruginosa (10(5) or 10(9) cfu) or saline as a control prior to wound closure (n = 6 per group). After 10 or 20 d, the meshes were harvested. The recovered meshes were analyzed for histologic changes and bacterial recovery as well as the material strength properties. Statistical significance (P < 0.05) was determined using 1-way analysis of variance or Mann-Whitney test. ADM and SIS colonized with 10(9) cfu P. aeruginosa showed an increased inflammatory response with an associated decrease in neo-vascularization (P < 0.05) at 20 d post-implantation compared with controls. P. aeruginosa had no effect on the tensile strength of ADM, but the tensile strength and modulus of elasticity were reduced for SIS compared with controls at 20 d. Bacterial colonization of ADM and SIS with 10(9)cfu P. aeruginosa negatively effected neovascularization and cellular re-population of the material over time but only SIS showed alterations in their biomechanical properties in response to this gram-negative bacterial challenge.

Apolipoprotein A-1 (apoA-1) deposition in, and release from, the enterocyte brush border: A possible role in transintestinal cholesterol efflux (TICE)?

Transintestinal cholesterol efflux (TICE) has been proposed to represent a non-hepatobiliary route of cholesterol secretion directly “from blood to gut” and to play a physiologically significant role in excretion of neutral sterols, but so far little is known about the proteins involved in the process. We have previously observed that apolipoprotein A-1 (apoA-1) synthesized by enterocytes of the small intestine is mainly secreted apically into the gut lumen during fasting where its assembly into chylomicrons and basolateral discharge is at a minimal level. In the present work we showed, both by immunomicroscopy and subcellular fractionation, that a fraction of the apically secreted apoA-1 in porcine small intestine was not released from the cell surface but instead deposited in the brush border. Cholesterol was detected in immunoisolated microvillar apoA-1, and it was partially associated with detergent resistant membranes (DRMs), indicative of localization in lipid raft microdomains. The apolipoprotein was not readily released from microvillar vesicles by high salt or by incubation with phosphatidylcholine-specific phospholipase C or trypsin, indicating a relatively firm attachment to the membrane bilayer. However, whole bile or taurocholate efficiently released apoA-1 at low concentrations that did not solubilize the transmembrane microvillar protein aminopeptidase N. Based on these findings and the well known role played by apoA-1 in extrahepatic cellular cholesterol removal and reverse cholesterol transport (RCT), we propose that brush border-deposited apoA-1 in the small intestine acts in TICE by mediating cholesterol efflux into the gut lumen.

Optical Strain Measurement and Tear-Out Behavior of Sutured Porcine Small Intestine Tissue Using a Standarized Procedure

Some of the major complications leading to high morbidity and mortality rates in intestine surgery are caused by anastomotic insufficiencies. As the suture represents a crucial factor for the successful treatment of intestine anastomosis, it is of critical importance to investigate the tearing of sutured tissue. The goal of this study consists in examining the tear-out characteristics of stitched porcine small intestinal tissue as a function of the position of the stitch, using an optical strain measurement system. Furthermore, the hole formation of two different suture materials (monofilament and braided) with a single stitch is examined and compared. A clear trend for strain characteristic cannot be found for all number of stitches. In the case of four stitches however, it can be observed that for four out of six samples the outer stitches show a higher strain distribution than the inner ones. The comparison of the hole formation indicates that tissue stitched with monofilament PDS II tears by exhibiting a broader deformation pattern than tissue stitched with braided Vicryl.

MRNA expression profiles of P450 3A enzymes in the liver and small intestine of the domestic pig

The cytochrome P450 (P450) 3A family is considered to be the most important and abundantly expressed P450 subfamily in mammals. The mRNA expression levels of four P450 3A enzymes in porcine liver and small intestine were investigated using real-time reverse transcriptase-polymerase chain reaction (RT-PCR). The expression of P450 3A mRNAs (P450 3A pool) was higher in the liver than that in the small intestine. In the small intestine, the P450 3A mRNAs were gradually decreased from the duodenum to the ileum. P450 3A29 and P450 3A22 were predominantly expressed both in liver and small intestine tissues with larger ratios in the P450 3A pool than the other P450 3A enzymes. These results demonstrate that P450 3A29 and P450 3A22 probably serve as the major P450 3A contributors for both the hepatic and intestinal P450 3A pool. This work provides a deeper comprehension of the contribution of P450 3A enzymes to xenobiotic metabolism in pigs.

Vaginal Paravaginal Repair With Porcine Small Intestine Submucosa

: This study aimed to determine the midterm efficacy of porcine small intestine submucosa for paravaginal repairs of anterior vaginal prolapse. : One hundred five women underwent repairs between 2003 and 2006 and met our inclusion criteria. Women were invited to return for a pelvic examination and to fill out validated questionnaires. Objective failure was defined as anterior prolapse recurrence at or beyond the hymen. : Fifty-nine women (56%) were available for follow-up. Median age of patients was 60 years (range, 26-80 years) and 83% had a parity of 2 or more. Ninety-seven percent of patients had a preoperative prolapse stage of 2 or more. Follow-up ranged from 1 to 5 years (median, 27.5 months; interquartile range, 14.5). The most common postoperative complication was transient voiding dysfunction (23.7%). Objective cure rate was 68.8%. A positive change in bladder, vaginal, and bowel symptoms (a little better, much better, or very much better) was reported by 69.5%, 59.3%, and 25.5% of women, respectively. Thirty-one women (52.5%) were sexually active at postoperative follow-up. Only 4 women (6.8%) were not sexually active because of pelvic symptoms. Dyspareunia was reported by 8.3% of the 48 women who returned for a clinic follow-up. Twenty-four women (40.7%) were not sexually active postoperatively, for reasons unrelated to their surgeries. : Vaginal paravaginal repair using porcine xenograft is a safe procedure whose long-term efficacy needs further evaluation through prospective trials.

The effect of bacterial infection on the biomechanical properties of biological mesh in a rat model.

BackgroundThe use of biologic mesh to repair abdominal wall defects in contaminated surgical fields is becoming the standard of practice. However, failure rates and infections of these materials persist clinically. The purpose of this study was to determine the mechanical properties of biologic mesh in response to a bacterial encounter.MethodsA rat model of Staphylococcus aureus colonization and infection of subcutaneously implanted biologic mesh was used. Samples of biologic meshes (acellular human dermis (ADM) and porcine small intestine submucosa (SIS)) were inoculated with various concentrations of methicillin-resistant Staphylococcus aureus [105, 109 colony-forming units] or saline (control) prior to wound closure (n = 6 per group). After 10 or 20 days, meshes were explanted, and cultured for bacteria. Histological changes and bacterial recovery together with biomechanical properties were assessed. Data were compared using a 1-way ANOVA or a Mann-Whitney test, with p<0.05.ResultsThe overall rate of staphylococcal mesh colonization was 81% and was comparable in the ADM and SIS groups. Initially (day 0) both biologic meshes had similar biomechanical properties. However after implantation, the SIS control material was significantly weaker than ADM at 20 days (p = 0.03), but their corresponding modulus of elasticity were similar at this time point (p>0.05). After inoculation with MRSA, a time, dose and material dependent decrease in the ultimate tensile strength and modulus of elasticity of SIS and ADM were noted compared to control values.ConclusionThe biomechanical properties of biologic mesh significantly decline after colonization with MRSA. Surgeons selecting a repair material should be aware of its biomechanical fate relative to other biologic materials when placed in a contaminated environment.

Optimizing the Management of Rotator Cuff Problems

Of the 31 recommendations made by the work group, 19 were determined to be inconclusive because of the absence of definitive evidence. Of the remaining recommendations, four were classified as moderate grade, six as weak, and two as consensus statements of expert opinion. The four moderate-grade recommendations include suggestions that exercise and nonsteroidal anti-inflammatory drugs be used to manage rotator cuff symptoms in the absence of a full-thickness tear, that routine acromioplasty is not required at the time of rotator cuff repair, that non-cross-linked, porcine small intestine submucosal xenograft patches not be used to manage rotator cuff tears, and that surgeons can advise patients that workers' compensation status correlates with less favorable outcomes after rotator cuff surgery.

Comparison of Two Porcine-Derived Materials for Repairing Abdominal Wall Defects in Rats

ObjectiveThe purpose of this study was to compare the mechanical properties, host responses and incorporation of porcine small intestine submucosa (PSIS) and porcine acellular dermal matrix (PADM) in a rat model of abdominal wall defect repair.Materials and MethodsPrior to implantation, PSIS and PADM were prepared and evaluated in terms of structure and mechanical properties. Full-thickness abdominal wall defects were created in 50 Sprague-Dawley rats, and were repaired using either PSIS or PADM. Rats were sacrificed 1, 2, 4, 8 and 12 weeks post-repair and examined for herniation, infection, adhesions, contraction, and changes in the thickness and strength of the tissues incorporated at the defect sites. Histopathology and immunohistochemistry were performed to analyze inflammatory responses, collagen deposition and vascularization.ResultsPADM showed more dense collagen deposition and stronger mechanical properties than PSIS prior to implantation (P<0.01). However, the mechanical properties observed after integration with the surrounding native tissues was similar for PADM and PSIS. Both PADM and PSIS showed significant contraction by week 12. However, PADM tissue induced less adhesion and increased in thickness more slowly, and showed less infiltration by foreign giant cells, polymorphonuclear cells, and mononuclear cells. Improved remodeling of host tissue was observed after PSIS implantation, which was apparent from the orientation of bands of fibrous connective tissue, intermixed with newly formed blood vessels by Week 12.ConclusionPSIS showed weaker mechanical properties prior to implantation. However, after implantation PSIS induced more pronounced host responses and showed better incorporation into host tissues than PADM.

Laparoscopic fixation of biologic mesh at the hiatus with fibrin or polyethylene glycol sealant in a porcine model.

The objective of this study was to determine the acute and chronic fixation strengths achieved by fibrin or polyethylene glycol (PEG) sealants to secure biologic mesh at the esophageal hiatus in a porcine model. For this study, 32 female domestic pigs were divided into four groups of 8 each. The four groups respectively received acute fibrin sealant, acute PEG sealant, chronic fibrin sealant, and chronic PEG sealant. Laparoscopically, a 5.5 × 8.5-cm piece of Biodesign Surgisis Hiatal Hernia Graft (porcine small intestine submucosa) was oriented with the U-shaped cutout around the gastroesophageal junction and the short axis in the craniocaudal direction to simulate hiatal reinforcement with a biologic mesh. The mesh then was secured with 2 ml of either fibrin sealant or PEG sealant. The pigs in the acute groups were maintained alive for 2 h to allow for complete polymerization of the sealants, and the pigs in the chronic group were maintained alive for 14 days. After the pigs were euthanized, specimens of the mesh-tissue interface were subjected to lap shear testing to determine fixation strength, and hematoxylin and eosin (H&E) stained slides were evaluated for evidence of remodeling. No significant differences were observed between the acute and chronic fixation strengths or the remodeling characteristics of the two sealants. However, fixation strength increased significantly over time for both types of sealant. Evidence of remodeling also was significantly more pronounced in the chronic specimens than in the acute specimens. This study demonstrated the feasibility of using fibrin or PEG sealants to secure biologic mesh at the hiatus in a porcine model.

Incorporation of essential and non‐essential fatty acids into distinct lipid classes in cultured bovine and porcine liver and small intestine explants

This study investigated fatty acid (FA) esterification patterns in ruminant and non-ruminant liver and small intestine (SI) explants. Explants were incubated in media containing 14C-labeled essential FA (EFA; C18:2 or C18:3) or non-EFA (C16:0 or C18:1), to track esterification of FA into lipid classes. Mean FA uptake was greater for porcine than bovine liver explants (23.9 vs 15.9±1.8 nmol/2 h/150 mg tissue, P=0.03). Liver cultures of both species incorporated more non-EFA than EFA (22.9 vs 16.9±1.6 nmol/2 h/150 mg tissue, P<0.001). Porcine SI cultures esterified more non-EFA than EFA (17.9 vs 12.4±2.0 nmol/2 h/150 mg tissue, P<0.001). Bovine liver and SI explants esterified more FA into triglyceride (TG) than phospholipid (PL) (Liver: 2.4 vs 1.4±0.4 nmol/2 h/150 mg tissue, P=0.04, SI: 3.5 vs 2.4±0.3 nmol/2 h/150 mg tissue, P=0.01). Porcine liver and SI explants did not exhibit preferential esterification of FA into either lipid class. Culture with EFA increased PL:TG in bovine liver explants, compared to non-EFA culture (0.68 vs 0.49±0.1 nmol/2 h/150 mg tissue, P=0.01). There was no difference in PL:TG in bovine SI explants, or porcine liver and SI explants cultured with EFA or non-EFA. Results suggest differing liver esterification patterns in bovids and porcids, with esterification patterns of ruminants possibly facilitating greater EFA esterification into PL. Support provided by NSF grant IOS-0920491.