Grafts In Dogs Research Articles

Effects of Autologous and Homologous Platelet Rich Plasma on Full Thickness Autologous Skin Graft in Dogs

Background: Wound healing is a complicated mechanism that includes inflammatory, proliferative and remodelling stages. Platelet rich plasma (PRP) is a small volume of blood plasma fortified with platelets and growth factors that enhance the healing by stimulating angiogenesis and formation of granulation tissue. Methods: The present study was performed to evaluate the effect of autologous and homologous platelet rich plasma on full thickness dermatological reconstructive surgery in dogs. The dogs were divided in two groups A and B, each with four clinical cases. In groups A and B, autologous and homologous PRP was used respectively as skin graft augmentation. The macroscopic parameters of the study included colour, edema, exudation and histopathological parameters included acute inflammation, fibroblast proliferation and granulation tissue formation. All these observations were made on days 3, 7 and 14 post-operatively. Result: On the basis of findings of this study, it was concluded that autologous PRP is a better graft healing promoter in terms of self-limiting acute inflammation, fibroblast proliferation, granular tissue and early healing of graft as compared to homologous PRP.

Surgical management of corneal ulcer using conjunctival pedicle graft in dogs

Surgical management of corneal ulcer using conjunctival pedicle graft in dogs

Augmentation of Carpal Arthrodesis Using Mesenchymal Stem Cells Derived Microvesicles and Cancellous Bone Graft in Dogs

Augmentation of Carpal Arthrodesis Using Mesenchymal Stem Cells Derived Microvesicles and Cancellous Bone Graft in Dogs

Cystosonographic and Cystographic Evaluations of Urinary Bladder Defects Managed with Composite Colo-Peritoneal Grafts in Dogs

Radiographic and ultrasonographic evaluations of the urinary bladder architecture following autologous composite colo-peritoneal pedicle graft, as alternative tissue for urinary bladder reconstruction, in the surgical repair of experimental urinary bladder defects were carried out in two dogs. Predetermined 2 ´ 4 cm dimension of urinary bladder defect was created on the dorsum of the urinary bladder, and was patched with harvested 3 ´ 5 cm composite colo-peritoneal pedicle flap. All operations were aseptically and humanely conducted. The gross anatomical evaluation of the urinary bladder architecture was performed by ultrasonography and contrast radiography of the repaired urinary bladder. Post-surgical cystosonographic assessments on day 8 showed thickened urinary bladder wall at the point of the graft, which decreased markedly on day 21. Cystographic evaluation revealed gradual transition of the urinary bladder architecture at the point of graft with clear delineation and minimal blurring at week 2 post-operation, which gradually disappeared at weeks 10 and 14. The cystosonographic and cystographic evaluations demonstrated evidence of advanced healing and well-preserved urinary bladder architecture with no evidence of leaks. The imaging modalities are adequately diagnostic to assess urinary bladder repairs following its management with composite colo-peritoneal graft in dogs.

Surgical treatment of canine and feline descemetoceles, deep and perforated corneal ulcers with autologous buccal mucous membrane grafts.

ObjectivesTo report the surgical technique and postoperative outcome of corneal repair with autologous buccal mucous membrane grafts in dogs and cats with descemetoceles, deep corneal ulcers, and perforated corneal ulcers with or without iris prolapse.Animal studiedTwelve cats (13 eyes) and fourteen dogs (14 eyes) were treated.ProceduresGrafts were harvested from the unpigmented superior labial mucosa using a biopsy punch. The corneal lesion was carefully debrided and cleaned. The graft was secured to the healthy cornea with a combination of simple interrupted and continuous 9–0 polyglycolic acid sutures. In 25/27 treated eyes, an overlying pedicle conjunctival graft was also performed. A temporary nictitating membrane flap was used in all cases. The pedicle conjunctival graft was trimmed about 10–20 days postoperatively. The median follow‐up period was 549.2 days (range 14–2691 days).ResultsNo surgical intra‐operative complications were observed. The ulcers healed and the integrity of the globe was restored in 24/27 treated eyes. Different grades of corneal fibrosis and/or vascularization and/or pigmentation were observed in all cases at the long‐term follow‐up. In two cases, enucleation was performed due to postoperative complications and one animal developed phthisis bulbi. A total of 22/27 treated eyes appeared to have regained effective visual function at the last clinical evaluation.ConclusionsAutologous buccal mucous membrane grafts appear to successfully manage severe corneal ulcers in dogs and cats, providing a useful and economical alternative to other corneal grafts.

Altered Immune Response to Decellularized Porcine Small Intestinal Sub-Mucosa (DPSIS) Graft in Dogs Suffering from Keratoconjunctivitis Sicca

Altered Immune Response to Decellularized Porcine Small Intestinal Sub-Mucosa (DPSIS) Graft in Dogs Suffering from Keratoconjunctivitis Sicca

Identification of Differentially Expressed Tear Proteins after Corneal Reconstruction with DPSIS Graft in Dogs Suffering from Keratoconjunctivitis Sicca

Identification of Differentially Expressed Tear Proteins after Corneal Reconstruction with DPSIS Graft in Dogs Suffering from Keratoconjunctivitis Sicca

Therapeutic Effects of Revascularisation on the Healing of Free Bone Grafts in Dogs.

IntroductionThe therapeutic effect of subcutaneous embedding and revascularisation on the repair of canine bone defects caused by open fracture was examined.Material and MethodsA total of 12 adult beagle dogs were randomly split into a control group (group C) and a test group (group T). A section of the radius was removed from each dog under general anaesthesia and the deficit supported by an orthopaedic implant. Group T had the section surgically implanted next to the blood vessel–rich saphenous vein and Group C had it cryopreserved at −80°C. After eight weeks, the bone was surgically implanted back into the matching radial deficit. Bone healing was evaluated by gross morphological and X-ray examinations, post-mortem histology, and successive blood measurements of key bone biochemical markers.ResultsAt 12 weeks, the bone healing boundary was disappearing more quickly in group T dogs than in their group C counterparts. X-ray and histological examinations showed that the cortical repair of group T subjects was complete and the bony plate arrangement was more regular than that in group C. The levels of bone biochemical markers also proved that the healing state of group T was better.ConclusionThe results showed that the degree of healing, osteoclast activity, and bone formation status of group T were better than those of group C, proving that the vascularised bone graft had a significantly shorter healing time than the cryopreserved bone graft.

A Comparison Between Autogenous Skin Graft and Alloskin Graft in Dogs

A Comparison Between Autogenous Skin Graft and Alloskin Graft in Dogs

Negative pressure wound therapy using polyvinyl alcohol foam to bolster full‐thickness mesh skin grafts in dogs

To report the use of negative pressure wound therapy (NPWT) with polyvinyl alcohol (PVA) foam to bolster full-thickness mesh skin grafts in dogs. Retrospective case series. Client-owned dogs (n = 8). Full-thickness mesh skin graft was directly covered with PVA foam. NPWT was maintained for 5 days (in 1 or 2 cycles). Grafts were evaluated on days 2, 5, 10, 15, and 30 for graft appearance and graft take, granulation tissue formation, and complications. Firm attachment of the graft to the recipient bed was accomplished in 7 dogs with granulation tissue quickly filling the mesh holes, and graft take considered excellent. One dog had bandage complications after cessation of the NPWT, causing partial graft loss. The PVA foam did not adhere to the graft or damage the surrounding skin. The application of NPWT with a PVA foam after full-thickness mesh skin grafting in dogs provides an effective method for securing skin grafts, with good graft acceptance. PVA foam can be used as a primary dressing for skin grafts, obviating the need for other interposing materials to protect the graft and the surrounding skin.

Retraction note: Histopathological features of bone regeneration in a canine segmental ulnar defect model

Today, finding an ideal biomaterial to treat the large bone defects, delayed unions and non-unions remains a challenge for orthopaedic surgeions and researchers. Several studies have been carried out on the subject of bone regeneration, each having its own advantages. The present study has been designed in vivo to evaluate the effects of cellular auto-transplantation of tail vertebrae on healing of experimental critical bone defect in a dog model. Six indigenous breeds of dog with 32 ± 3.6 kg average weight from both sexes (5 males and 1 female) received bilateral critical-sized ulnar segmental defects. After determining the health condition, divided to 2 groups: The Group I were kept as control I (n = 1) while in Group II (experimental group; n = 5) bioactive bone implants were inserted. The defects were implanted with either autogeneic coccygeal bone grafts in dogs with 3-4 cm diaphyseal defects in the ulna. Defects were stabilized with internal plate fixation, and the control defects were not stabilized. Animals were euthanized at 16 weeks and analyzed by histopathology. Histological evaluation of this new bone at sixteen weeks postoperatively revealed primarily lamellar bone, with the formation of new cortices and normal-appearing marrow elements. And also reformation cortical compartment and reconstitution of marrow space were observed at the graft-host interface together with graft resorption and necrosis responses. Finally, our data were consistent with the osteoconducting function of the tail autograft. Our results suggested that the tail vertebrae autograft seemed to be a new source of autogenous cortical bone in order to supporting segmental long bone defects in dogs. Furthermore, cellular autotransplantation was found to be a successful replacement for the tail vertebrae allograft bone at 3-4 cm segmental defects in the canine mid- ulna. Clinical application using graft expanders or bone autotransplantation should be used carefully and requires further investigation. The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2028232688119271

In this issue - September 2016: Portable negative pressure wound therapy for skin grafts in dogs · Wellness testing in small animals · Effects of pimobendan on myocardial perfusion and pulmonary transit time in dogs · Rispens CVI988 vaccine virus and Marek's disease virus in poultry · A field study of ovulation in oestrus mares · Post-weaning growth of beef

In this issue - September 2016: Portable negative pressure wound therapy for skin grafts in dogs · Wellness testing in small animals · Effects of pimobendan on myocardial perfusion and pulmonary transit time in dogs · Rispens CVI988 vaccine virus and Marek's disease virus in poultry · A field study of ovulation in oestrus mares · Post-weaning growth of beef

Lyophilized allografts without pre-treatment with glutaraldehyde are more suitable than cryopreserved allografts for pulmonary artery reconstruction.

Various methods are available for preservation of vascular grafts for pulmonary artery (PA) replacement. Lyophilization and cryopreservation reduce antigenicity and prevent thrombosis and calcification in vascular grafts, so both methods can be used to obtain vascular bioprostheses. We evaluated the hemodynamic, gasometric, imaging, and macroscopic and microscopic findings produced by PA reconstruction with lyophilized (LyoPA) grafts and cryopreserved (CryoPA) grafts in dogs. Eighteen healthy crossbred adult dogs of both sexes weighing between 18 and 20 kg were used and divided into three groups of six: group I, PA section and reanastomosis; group II, PA resection and reconstruction with LyoPA allograft; group III, PA resection and reconstruction with CryoPA allograft. Dogs were evaluated 4 weeks after surgery, and the status of the graft and vascular anastomosis were examined macroscopically and microscopically. No clinical, radiologic, or blood-gas abnormalities were observed during the study. The mean pulmonary artery pressure (MPAP) in group III increased significantly at the end of the study compared with baseline (P=0.02) and final [P=0.007, two-way repeat-measures analysis of variance (RM ANOVA)] values. Pulmonary vascular resistance of groups II and III increased immediately after reperfusion and also at the end of the study compared to baseline. The increase shown by group III vs group I was significant only if compared with after surgery and study end (P=0.016 and P=0.005, respectively, two-way RM ANOVA). Microscopically, permeability was reduced by ≤75% in group III. In conclusion, substitution of PAs with LyoPA grafts is technically feasible and clinically promising.

RETRACTED ARTICLE: Histopathological features of bone regeneration in a canine segmental ulnar defect model

BackgroundToday, finding an ideal biomaterial to treat the large bone defects, delayed unions and non-unions remains a challenge for orthopaedic surgeions and researchers. Several studies have been carried out on the subject of bone regeneration, each having its own advantages. The present study has been designed in vivo to evaluate the effects of cellular auto-transplantation of tail vertebrae on healing of experimental critical bone defect in a dog model.MethodsSix indigenous breeds of dog with 32 ± 3.6 kg average weight from both sexes (5 males and 1 female) received bilateral critical-sized ulnar segmental defects. After determining the health condition, divided to 2 groups: The Group I were kept as control I (n = 1) while in Group II (experimental group; n = 5) bioactive bone implants were inserted. The defects were implanted with either autogeneic coccygeal bone grafts in dogs with 3-4 cm diaphyseal defects in the ulna. Defects were stabilized with internal plate fixation, and the control defects were not stabilized. Animals were euthanized at 16 weeks and analyzed by histopathology.ResultsHistological evaluation of this new bone at sixteen weeks postoperatively revealed primarily lamellar bone, with the formation of new cortices and normal-appearing marrow elements. And also reformation cortical compartment and reconstitution of marrow space were observed at the graft-host interface together with graft resorption and necrosis responses. Finally, our data were consistent with the osteoconducting function of the tail autograft.ConclusionsOur results suggested that the tail vertebrae autograft seemed to be a new source of autogenous cortical bone in order to supporting segmental long bone defects in dogs. Furthermore, cellular autotransplantation was found to be a successful replacement for the tail vertebrae allograft bone at 3-4 cm segmental defects in the canine mid- ulna. Clinical application using graft expanders or bone autotransplantation should be used carefully and requires further investigation.Virtual slidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2028232688119271.

Effects of Negative Pressure Wound Therapy on Healing of Free Full‐Thickness Skin Grafts in Dogs

To compare healing of free, full-thickness, meshed skin grafts under negative pressure wound therapy (NPWT) with bolster dressings in dogs. Randomized, controlled experimental study, paired design. Dogs (n = 5) METHODS: Full-thickness skin wounds (4 cm × 1.5 cm) were created bilaterally on the antebrachia of 5 dogs (n = 10). Excised skin was grafted to the contralateral limb. Grafts were randomized to NPWT or bolster dressings (control; CON). NPWT was applied continuously for 7 days. Grafts were evaluated on Days 2, 4, 7, 10, 14, and 17, biopsied on days 0, 4, 7, and 14, and had microbial culture on Day 7. Outcome variables were: time to first appearance of granulation tissue, percent graft necrosis, and percent open mesh. Significance was set at P < .05. Histologic findings, culture results, and graft appearance were reported. Granulation tissue appeared earlier in the NPWT grafts compared with CON grafts. Percent graft necrosis and remaining open mesh area were both greater in CON grafts compared with NPWT grafts at most time points. Histologic results showed no significant difference in all variables measured, and all cultures were negative. Variables of graft acceptance were superior when NPWT was used in the first week post-grafting. Fibroplasia was enhanced, open meshes closed more rapidly and less graft necrosis occurred with NPWT application. More preclinical studies are required to evaluate histologic differences.

Comparative study between fibrin glue and platelet rich plasma in dogs skin grafts

Compare fibrin glue (Tissucol(®)) and platelet-rich plasma in full-thickness mesh skin grafts in dogs. Eighteen dogs were used, divided into two groups: fibrin glue (FG) and platelet-rich plasma (PRP). In all the animals, a full-thickness 3x3 cm mesh skin graft was implanted. In the left limb, the biomaterial was place between the graft and the receptor bed, according to the group, while the right limb served as the control group. All the animals were evaluated clinically every 48 hours until the 14th day, using the variables of exudation, coloration, edema and cosmetic appearance. Three animals were evaluated histologically, on the third, seventh and tenth postoperative days, using the variables of fibroblasts, collagen, granulation tissue, microscopic integration-adherence and acute inflammation. Clinical evaluations showed that the group CF showed better scores for all variables compared to PRP group. On the histological evaluations PRP group had a higher presence of fibroblasts in the seventh and fourteenth days. The fibrin glue group was clinically superior to the platelet-rich group when used on full-thickness skin grafts in dogs.

Histomorphometric Analysis and Regional Variations of Full Thickness Skin Grafts in Dogs

To (1) compare thickness of the epidermis and dermis of anatomically different donor sites in dogs, and (2) evaluate hair follicle damage during full thickness skin grafts (FTSG) preparation from anatomically different donor sites. Another objective was to compare the extent of agreement between gross and histologic quality of graft preparation. Ex vivo study. Healthy Beagle dogs (n = 12). Skin samples were harvested from fresh cadavers free of gross dermatopathology and FTSG prepared. Regional, epidermal and dermal thickness, and hair follicle density in intact skin and FTSG specimens from different regions were determined by histomorphometric analysis. Hair follicle density in intact skin and FTSG specimens, and skin thickness measurements were compared among regions. Mean epidermis and dermis thickness of the dorsal lumbar and lateral neck regions were significantly greater when compared with other sites. Total hair follicle (superficial and deep dermis) densities were significantly less in prepared FTSG versus intact skin specimens. The dorsal lumbar region had the highest hair follicle density. Thickness of the epidermis and dermis is dependent on body region. Hair follicle density in the FTSG specimens was decreased compared with intact skin specimens, which may affect hair regrowth in FTSG.

Outside Fibroblasts Play a Key Role in the Development of Inner Neointima After the Implantation of Polytetrafluoroethylene Grafts

The neointima formation inside of polytetrafluoroethylene (PTFE) grafts may be associated with the migration of outside fibroblasts to the luminal surfaces. This study aimed to verify whether blockade of fibroblast migration can prevent neointima formation by testing two types of prosthetic vessels, the porous PTFE graft and the impermeable Grasil graft, respectively. After implantation of the PTFE graft in dogs, a time-dependent migration of outside fibroblasts to the luminal side occurred. Compared with the PTFE grafts, the total neointima formation in the Grasil grafts was significantly less. Although the neointima formation at the arterial or venous anastomotic regions did not significantly differ between the two grafts, the neointima at the middle region of the PTFE grafts was significantly evident than the Grasil grafts. The components of the renin–angiotensin system (RAS), such as angiotensin II and its receptor AT1, as well as the forming enzymes of the RAS (angiotensin-converting enzyme and chymase), were all detectable in the grafts’ surrounding tissues. Neointima formation at the middle region of the prosthetic vessels could be suppressed almost completely by the blockade of outside fibroblast migration, indicating that outside fibroblasts play a key role in the formation of neointima in this region.

Experimental results of using autologous rectus fascia sheath for venous patch grafts in dogs

Autologous vascular patch grafts developed from the internal rectus sheath were implanted onto the bilateral common iliac vein and jugular vein of 4 experimental beagle dogs. During the development and implanting of the grafts no technical difficulties or perioperative complications were encountered. The follow-up lasted 6 months and 3 months in the case of the common iliac vein grafts and the jugular grafts, respectively. In the postoperative period, the morphological and functional characteristics of the implanted venous sections were examined by Doppler ultrasonography and CT angiography. Normal patency was detected, and none of these check-ups showed obturation or stenosis. The histological survey showed no mesothelial cell layer, but the insides of the grafts showed total restructuring and were covered by a normal endothelial layer. No difference could be detected between samples harvested 3 and 6 months after implanting. The immunohistochemical examinations using anti-claudin-5 and anti-CD31 antibodies confirmed the preliminary results of the histological examinations that the luminal surfaces of the implanted grafts developed a differentiated monolayer endothelium which was free of degenerative and inflammatory signs. The control examinations show the suitability of the internal rectus sheath as a venous wall donor.

Mandibular Segmental Defect Regenerated With Macroporous Biphasic Calcium Phosphate, Collagen Membrane, and Bone Marrow Graft in Dogs

To reconstruct segmental mandibulectomy using calcium phosphate ceramics and collagen membrane with a delayed bone marrow grafting in experimental animals. Defects of segmental mandibulectomy were filled with calcium phosphate granules and wrapped with a collagen membrane in 4 dogs and left empty as a control in 2 dogs. Two months later, a bone marrow graft was injected into the center of the implants. Animals were humanely killed after a 16-week delay. Six adult beagles were included in this study. Segmental mandibulectomy. Bone ingrowth and material resorption in the reconstructed segment. Successful osseous colonization bridged the whole length of the defects. The good new bone formation at the center and the periosteum-like formation at the periphery suggest the osteoinductive role of the bone marrow graft and the healing scaffold role of the membrane. This model succeeded in regenerating a large segmental defect in the mandible. An investigation with a postimplantation radiation delivery schedule is required with the use of this model, which should be considered as a preclinical study for a bone tissue engineering approach in patients with cancer-related bone defects.