Enhanced susceptibility to infections in a diabetic wound healing model

<p>Abstract</p> <p>Background</p> <p>Wound infection is a common complication in diabetic patients. The progressive spread of infections and development of drug-resistant strains underline the need for further insights into bacterial behavior in the host in order to develop new therapeutic strategies. The aim of our study was to develop a large animal model suitable for monitoring the development and effect of bacterial infections in diabetic wounds.</p> <p>Methods</p> <p>Fourteen excisional wounds were created on the dorsum of diabetic and non-diabetic Yorkshire pigs and sealed with polyurethane chambers. Wounds were either inoculated with 2 × 10⁸Colony-Forming Units (CFU) of <it>Staphylococcus aureus </it>or injected with 0.9% sterile saline. Blood glucose was monitored daily, and wound fluid was collected for bacterial quantification and measurement of glucose concentration. Tissue biopsies for microbiological and histological analysis were performed at days 4, 8, and 12. Wounds were assessed for reepithelialization and wound contraction.</p> <p>Results</p> <p>Diabetic wounds showed a sustained significant infection (>10⁵CFU/g tissue) compared to non-diabetic wounds (p < 0.05) over the whole time course of the experiment. <it>S. aureus</it>-inoculated diabetic wounds showed tissue infection with up to 8 × 10⁷CFU/g wound tissue. Non-diabetic wounds showed high bacterial counts at day 4 followed by a decrease and no apparent infection at day 12. Epidermal healing in <it>S. aureus</it>-inoculated diabetic wounds showed a significant delay compared with non-inoculated diabetic wounds (59% versus 84%; p < 0.05) and were highly significant compared with healing in non-diabetic wounds (97%; p < 0.001).</p> <p>Conclusion</p> <p>Diabetic wounds developed significantly more sustained infection than non-diabetic wounds. <it>S. aureus </it>inoculation leads to invasive infection and significant wound healing delay and promotes invasive co-infection with endogenous bacteria. This novel wound healing model provides the opportunity to closely assess infections during diabetic wound healing and to monitor the effect of therapeutical agents <it>in vivo</it>.</p

The endovascular management of a 3.5-cm gastroduodenal artery aneurysm presenting with gastritis and recurrent pancreatitis

Visceral artery aneurysms (VAAs) are a rare entity. Within this subset of aneurysms, gastroduodenal artery (GDA) aneurysms represent an even more rare occurrence. We present a case report of treating GDA aneurysm on semi-elective basis followed by literature review of the clinical presentation and mainstream treatment modalities. GO is a 65-year-old male, with 6-month history of recurrent epigastric pain. He was found to have acute pancreatitis and an adjacent 3.5-cm GDA aneurysm. After conservative treatment of pancreatitis, the aneurysm was treated with coil embolization of the sac and GDA. Most VAAs are asymptomatic; GDA aneurysms tend to present clinically with epigastric pain or pancreatitis. In addition, together with pancreaticoduodenal aneurysms, GDA aneurysms warrant immediate intervention once diagnosed. Open surgical options for VAAs include aneurysm resection with or without revascularization (i.e., bypass), aneurysm ligation, or end-organ resection (i.e., splenectomy). Endovascular repair involves coil embolization with or without stent placement. While endovascular modality continues to be the first choice for stable elective VAA patients, modality of treatment for ruptured VAA or unstable patients will vary according to the patient's overall status, operator's experience, and institute capacity

Minced Skin for Tissue Engineering of Epithelialized Subcutaneous Tunnels

We used minced, autologous skin for neoepithelialization of surgically created subcutaneous tunnels in a large animal model. Partial-thickness skin grafts were harvested from the back region of five 50–60 kg Yorkshire pigs. The skin was minced to 0.8 × 0.8 × 0.3 mm particles. Silicone-latex tubes were covered with fibrin, rolled in minced skin, and placed in subcutaneous tunnels created in the abdominal area. For comparison, single cell suspensions of keratinocytes and fibroblasts in fibrin or fibrin only were transplanted on tubes. Tunnels were extracted after 14, 21, and 28 days for microscopic evaluation. All tubes transplanted with minced skin particles showed neoepithelialization. The epithelium was stratified and differentiated after 2 weeks in vivo, and the stratum corneum was directed toward the implanted tube. No epithelium formed from tubes transplanted with single cell suspensions, and only sparse keratinocytes could be detected by serial sectioning and immunostaining on day 14, but not later. No epithelial lining was found in tunnels with fibrin-only-coated tubes. Epithelial cysts could be found the first 2 weeks after transplantation in the minced skin group but not later. In conclusion, a minced skin technique could serve as a potential source for tissue engineering of tubular conduits for reconstructive purposes of the urethra and for cutaneous stomas for bladder catheterization, or intestinal irrigations. The method would have the advantage of being simple and expeditious and not requiring in vitro culturing

Impaired wound healing in an acute diabetic pig model and the effects of local hyperglycemia

Diabetic wounds result in significant morbidity, prolonged hospitalization, and enormous health-care expenses. Pigs have been shown to have wound healing resembling that in humans. The aim of this study was to develop a large-animal model for diabetic wound healing. Diabetes was induced by streptozotocin injection in Yorkshire pigs. Full-thickness wounds were created and dressed with a sealed chamber. Nondiabetic pigs with or without high glucose wound fluid concentration served as controls. Glucose concentration in serum and wound fluid was measured and collected. Wound contraction was monitored, and biopsies were obtained for measurement of reepithelialization. Wound fluid was analyzed for insulin-like growth factor-1 (IGF-1), platelet-derived growth factor, and transforming growth factor. Glucose concentration in wound fluid initially followed serum levels and then decreased to undetectable on day 9. Reepithelialization was significantly delayed in diabetic pigs. In nondiabetic pigs, wounds treated in a local hyperglycemic environment, and thus excluding the effects of systemic hyperglycemia, showed no difference in wound closure compared with controls. This suggests that delayed wound healing in diabetes is not induced by local high-glucose concentration itself. Analysis of growth factor expression showed a marked reduction in IGF-1 in the diabetic wounds. Diabetic pigs have impaired healing that is accompanied by a reduction of IGF-1 in the healing wound and is not due to the local hyperglycemia condition itself

Non-diabetic wounds 97*/- 5% reepithelialization, -inoculated non-diabetic wounds: 87 /- 22%

Diabetic wounds showed 84 +/- 15%, and -inoculated diabetic wounds were 59 +/- 8% reepithelialized. + = p < 0.05 diabetic versus non-diabetic wounds; * = p < 0.05 -noculated diabetic versus non-inoculated diabetic wounds; # = p < 0.05 S. aureus-inoculated diabetic versus -inoculated non-diabetic wounds; § = p < 0.001 -inoculated diabetic wounds versus non-diabetic wounds.<p><b>Copyright information:</b></p><p>Taken from "Enhanced susceptibility to infections in a diabetic wound healing model"</p><p>http://www.biomedcentral.com/1471-2482/8/5</p><p>BMC Surgery 2008;8():5-5.</p><p>Published online 29 Feb 2008</p><p>PMCID:PMC2276479.</p><p></p