Delayed Ulcer Healing Research Articles

Steroid Treatment Impairs Intestinal Stem Cell (ISC) Activation and Contributes to Delayed Ulcer Healing in Inflammatory Bowel Disease (IBD)

In cases of moderate to severe inflammatory bowel disease (IBD), exogenous glucocorticoid steroids (GC) are the preferred treatment due to their safety and efficacy in alleviating symptoms. Despite the clinical benefits, endoscopic data show that GCs delay ulcer healing through mechanisms that are poorly understood. Intestinal stem cells (ISC) require Wnt/β‐catenin signaling for maintenance of the crypt proliferative compartment, and Wnt responsiveness is an important component of a functional mucosal healing response. The objective of our study was to determine whether GCs impair ISC activation in ulcer re‐epithelialization. Specifically, we hypothesized that that steroids impair canonical Wnt/β‐catenin signaling required for ISC activation needed for mucosal repair.MethodsWe examined the effects of dexamethasone, a GC steroid, on cell signaling pathways involved in Wnt/β‐catenin, PI3 Kinase, and NFkB signaling. We utilized NCM460 (NCM) cells, a normal human colonic intestinal epithelial cell (IEC) line, mouse epithelial cells isolated after DSS‐mediated colitis induction, and epithelial isolations from patient biopsies obtained from University of Kentucky and VA Lexington Hospitals. IEC from untreated and steroid‐treated (7 days) UC patients with equivalent levels of colitis were compared.ResultsIn steroid‐treated NCMs, we saw a significant decrease in transcript levels of Wnt target gene Axin2, a marker of Wnt‐responsive multipotent IECs that participate directly in ulcer healing, and the β‐catenin transcriptional co‐activator CREB Binding Protein (CBP). After transfecting NCM460s with lentivirus containing a TCF/LEF luciferase construct (a marker of Wnt transcriptional activation), we saw that steroid treatment diminished TNF‐mediated increase in TCF/LEF signaling back to control levels. In both murine and IECs isolated from patient biopsies, GC inhibited colitis‐induced Axin2, p‐LRP6 (marker of Wnt signaling) and nuclear β‐catenin protein levels. Together, these data indicate strongly that GCs impair Wnt signaling.DiscussionOur results indicate that GCs impair Wnt/β‐catenin signaling during ulcer healing in in vitro and in vivo models of colitis. While steroids play a significant role in regulating the basal immune response to IBD, our data suggest steroids inhibit epithelial signaling required for ulcer healing. Given the recent data implicating NFkB in Wnt signaling activation, our studies suggest a potential explanation for GC‐induced impairment of stem cell activation needed for mucosal repair in IBD.Support or Funding Information1I01CX001353‐01A1 VA Merit 5TL1TR000115‐05 TL1 Pre‐doctoral CTSA Funding

Real-Time Smart Textile-Based System to Monitor Pressure Offloading of Diabetic Foot Ulcers.

The lifetime risk of developing a diabetic foot ulcer (DFU) is at least 25%. A DFU carries a 50% risk for infection and at least 20% of those receive some form of amputation. The most significant parameter that prevents or delays ulcer healing is high plantar pressure. To improve the patient's healing process, the DFU's plantar pressure should remain cumulatively low. Therefore, a tool that continuously measures the DFU loading, and provides real-time feedback can improve the healing outcome. We report the development of a system capable of continuously measuring the pressure, which could have applications to monitor DFU. The system contains a textile pressure sensor attached to a stretchable band, hardware that collects data and transmits them via Bluetooth to a phone, an app that gathers the data and stores them in the cloud, and a web dashboard that displays the data to the clinician. The sensor was characterized in vitro using the system, and the web-dashboard was developed and tested on simulated patient data. We demonstrate the feasibility of developing the system and characterize the pressure response of the device. As a result, we demonstrate a viable method for monitoring DFU off-loading in real time. The presented study demonstrates the feasibility to develop a simple, modular wearable system that opens up new possibilities for diabetic foot ulcer care by providing a way of monitoring the pressure under the ulcer in real time.

Distinct Wound Healing and Quality-of-Life Outcomes in Subgroups of Patients With Venous Leg Ulcers With Different Symptom Cluster Experiences

ContextAdults with venous leg ulcers frequently experience multiple symptoms that may influence quality of life (QOL). ObjectivesThe objective of this study was to identify patient subgroups based on their experience with a pain-depression-fatigue-sleep disturbance symptom cluster and to identify differences in patient characteristics and wound-healing and QOL outcomes between the subgroups. MethodsSecondary data analysis from previous longitudinal studies of 247 patients with venous leg ulcers. Latent class analysis identified subgroups of patients with distinct experiences with the symptom cluster of pain, depression, fatigue, and sleep disturbance. Hierarchical regression analysis identified relationships between the subgroups and QOL outcomes. Survival analysis identified differences between the subgroups and ulcer healing. ResultsLatent class analysis found 67% of patients were in a mild symptom subgroup (i.e., experiencing no or mild pain, depressive symptoms, fatigue, or sleep disturbance). One-third of the samples were in a severe symptom subgroup, who reported moderate-to-severe levels of these symptoms. Compared with the mild subgroup, patients in the severe subgroup had poorer QOL scores (t = 8.06, P < 0.001). Symptom subgroup membership accounted for 19% of the variance (P < 0.001) within a hierarchical regression model that explained 42% of the variance in QOL (F(7,170) = 16.89, P < 0.001, R2 = 0.42). Cox proportional hazards regression found that at enrollment into the study, patients in the severe symptom subgroup were 1.5 times (95% confidence interval 1.02–2.08) less likely to heal in the following 24 weeks (P = 0.037). ConclusionSignificant relationships were found between delayed ulcer healing, decreased QOL, and membership in the severe symptom subgroup. These findings suggest that comprehensive symptom assessment is needed to identify patients at higher risk for poor outcomes and enable early intervention.

A Cytosolic Multiprotein Complex Containing p85α Is Required for β-Catenin Activation in Colitis and Colitis-associated Cancer

Wnt/β-catenin signaling is required for crypt structure maintenance. We previously observed nuclear accumulation of Ser-552 phosphorylated β-catenin (pβ-Cat(Ser-552)) in intestinal epithelial cells (IEC) during colitis and colitis-associated cancer. Data here delineate a novel multiprotein cytosolic complex (MCC) involved in β-catenin signaling in the intestine. The MCC contains p85α, the class IA subunit of PI3K, along with β-catenin, 14-3-3ζ, Akt, and p110α. MCC levels in IEC increase in colitis and colitis-associated cancer patients. IEC-specific p85α-deficient (p85(ΔIEC)) mice develop more severe dextran sodium sulfate colitis due to delayed ulcer healing and reduced epithelial β-catenin activation. In colonic IEC, p85α deficiency did not alter PI3K signaling. In vitro shRNA depletion of individual complex members disrupts the MCC and reduces β-catenin signaling. Despite worse colitis, p85(ΔIEC) mice have reduced tumor burden after azoxymethane/dextran sodium sulfate treatment. Together the data indicate that the β-catenin MCC is needed for mucosal repair and carcinogenesis. This novel MCC may be an attractive therapeutic target in preventing cancer in colitis patients.

Vonoprazan 20 mg vs lansoprazole 30 mg for endoscopic submucosal dissection-induced gastric ulcers.

AIMTo compare the healing effects of vonoprazan and lansoprazole on gastric ulcers induced by endoscopic submucosal dissection (ESD).METHODSData were obtained from a total of 26 patients. Fourteen patients were randomized to the vonoprazan group and 12 were randomized to the lansoprazole group. Patients were administered either 20 mg vonoprazan or 30 mg lansoprazole per day after ESD. Endoscopic images just after ESD, on day 8, and on day 28 were used for the evaluation of the shrinking rate of ESD ulcers. The shrinking rates and the incidence of delayed bleeding were compared between the 2 groups.RESULTSThe shrinking rates of ESD ulcers on day 8 [vonoprazan group: 61.8% (range: 24.0%-91.1%), lansoprazole group: 71.3% (range: 25.2%-88.6%)] and on day 28 [vonoprazan group: 95.3% (range: 76.2%-100%), lansoprazole group: 97.2% (range: 81.1%-99.8%)] were not statistically different between the 2 groups. On day 28, most of the ulcers in both groups healed to more than 90%, whereas 3 of 14 (21.4%) in the vonoprazan group and 1 of 12 (8.3%) in the lansoprazole group had delayed ulcer healing, which was not statistically different (P = 0.356). The frequency of delayed bleeding was 0 in the both groups. Taken together, there were no significant differences between the two drug groups.CONCLUSIONOur study indicates that vonoprazan is potent for the management of ESD ulcers although lansoprazole is also sufficient and cost-effective.

Non-Helicobacter pylori, Non-nonsteroidal Anti-inflammatory Drug Peptic Ulcer Disease

Non-Helicobacter pylori, non-NSAID peptic ulcer disease (PUD), termed idiopathic PUD, is increasing in Korea. Diagnosis is based on exclusion of common causes such as H. pylori infection, infection with other pathogens, surreptitious ulcerogenic drugs, malignancy, and uncommon systemic diseases with upper gastrointestinal manifestations. The clinical course of idiopathic PUD is delayed ulcer healing, higher recurrence, higher re-bleeding after initial ulcer healing, and higher mortality than the other types of PUD. Genetic predisposition, older age, chronic mesenteric ischemia, cigarette smoking, concomitant systemic diseases, and psychological stress are considered risk factors for idiopathic PUD. Diagnosis of idiopathic PUD should systematically explore all possible causes. Management of this disease is to treat underlying disease followed by regular endoscopic surveillance to confirm ulcer healing. Continuous proton pump inhibitor therapy is an option for patients who respond poorly to the standard ulcer regimen.

Risk factors of delayed ulcer healing after gastric endoscopic submucosal dissection.

Although post-endoscopic submucosal dissection (ESD) iatrogenic ulcer is known to heal faster than peptic ulcer, some iatrogenic ulcers show delayed healing. The aim of this study was to clarify risk factors of delayed ulcer healing after gastric ESD. We retrospectively reviewed medical records of all patients who had ESD for gastric neoplasms (866 adenomas and 814 early gastric cancers) between January 2005 and February 2011. Of 1680 subjects, 95 had delayed ulcer healing in 3-month follow-up. Multivariate analysis showed that diabetes (OR 1.743; 95% CI 1.017-2.989, p = 0.043), coagulation abnormality (OR 3.195; 95% CI 1.535-6.650, p = 0.002), specimen size greater than 4 cm (OR 2.999; 95% CI 1.603-5.611, p = 0.001), and electrocoagulation (OR 7.149; 95% CI 1.738-29.411, p = 0.006) were revealed to be independent risk factors of delayed ulcer healing. Meanwhile, persistent Helicobacter pylori infection was not related to the delayed ulcer healing. Large iatrogenic ulcer by ESD with massive hemostasis, especially in patients with diabetes mellitus or coagulation abnormalities, tends to take more than 3 months to heal. For such cases, initial dosage increment of PPI or addition of other anti-ulcer agents after ESD may be beneficial.

Congestive heart failure presence predicts delayed healing of foot ulcers in diabetes: An audit from a multidisciplinary high-risk foot clinic

AimsThis retrospective study aimed to investigate both established and less well-explored factors as potential predictive variables for failed and delayed ulcer healing. MethodsPatients with type 1 or 2 diabetes with foot ulceration presenting consecutively to, and then subsequently managed at, a multidisciplinary, high-risk foot clinic were followed until ulcer healing, amputation or death. Data comprised prospective standardised documentation at each visit and retrospective collection from hospital records, and included patient demographics, comorbidities, laboratory variables, and ulcer infection, depth and area at each presentation. Multiple regression analysis was used to determine independent predictors of failure to heal and delayed healing. ResultsOf the 107 consecutive patients studied, 95 (89%) healed overall, 50 (47%) had healed in 12 weeks and the mean healing rate was a 10% decrease in ulcer area per week. Amongst all variables examined, comorbid congestive heart failure (CHF) was the only factor independently predictive of all measured outcomes of failure to heal overall, delayed healing at 12 weeks, and reduced healing rate. Ulcer infection at presentation, longer duration of antibiotic use, and liver enzyme abnormalities of raised ALT and AST:ALT<1 (each suggestive of non-alcoholic fatty liver disease), were also predictive of poor ulcer outcomes. ConclusionsComorbid congestive cardiac failure is predictive of delayed foot ulcer healing rate as well as a lower probability of healing overall. Liver enzyme abnormalities also predicted delayed ulcer healing outcomes. The mechanisms underlying these associations with foot ulcer outcomes in diabetes are unclear. Further studies are needed to determine the role of systematic routine documentation of heart failure and its severity, and then targeting of heart failure to potentially aid the management of foot ulcers in diabetes.

Diagnostic and Treatment Approaches for Refractory Peptic Ulcers.

Refractory peptic ulcers are defined as ulcers that do not heal completely after 8 to 12 weeks of standard anti-secretory drug treatment. The most common causes of refractory ulcers are persistent Helicobacter pylori infection and use of nonsteroidal anti-inflammatory drugs (NSAIDs). Simultaneous use of two or more H. pylori diagnostic methods are recommended for increased sensitivity. Serologic tests may be useful for patients currently taking proton pump inhibitors (PPIs) or for suspected false negative results, as they are not affected by PPI use. NSAID use should be discontinued when possible. Platelet cyclooxygenase activity tests can confirm surreptitious use of NSAIDs or aspirin. Cigarette smoking can delay ulcer healing. Therefore, patients who smoke should be encouraged to quit. Zollinger-Ellison syndrome (ZES) is a rare but important cause of refractory gastroduodenal ulcers. Fasting plasma gastrin levels should be checked if ZES is suspected. If an ulcer is refractory despite a full course of standard PPI treatment, the dose should be doubled and administration of another type of PPI considered.

Bio-sheet graft therapy for artificial gastric ulcer after endoscopic submucosal dissection: an animal feasibility study

Various bio-sheet grafts have been attempted either to accelerate healing of artificial ulcers or to prevent adverse events after endoscopic submucosal dissection (ESD), but neither prospective nor mechanistic studies were available. To evaluate the substantial effect of a bio-sheet graft on artificial ulcer healing and its feasibility as an endoscopic treatment modality. Preclinical, invivo animal experiment and proof-of-concept study. Animal laboratory. Three mini-pigs, Sus scrofa, mean age 14 months. Multiple ulcers sized 2.5 cm in diameter were generated by ESD in 3 mini-pigs and were assigned randomly into the following 3 groups; control group, bio-sheet group, or combination (bio-sheet plus drug) group. Bio-sheet grafts or bio-sheet plus drug combinations were applied on the artificial ulcers immediately after the ESD. Feasibility and efficacy of endoscopic bio-sheet graft therapy for the management of artificial ulcers and the evaluation of healing conditions based on histology changes in the remaining gastric bed tissues harvested from the stomachs. Thirty-three ESD specimens were obtained. On an image analysis of the ratio of healed area in the remaining gastric bed tissue compared with the matched dissected gastric mucosa, the control group showed the most significant improvement in healing activity among the 3 groups (P< .05), whereas the severity of inflammation in the remaining ulcer tissue was significantly attenuated in bio-sheet and combination groups (P< .05). Animal model. Although the bio-sheet grafts provided physical protection from gastric acid attack as reflected in the attenuated inflammation on the ulcer beds, unexpected delayed ulcer healing was noted in the bio-sheet graft group because of its physical hindrance of the healing process.

Motility and chemotaxis mediate the preferential colonization of gastric injury sites by Helicobacter pylori.

Helicobacter pylori (H. pylori) is a pathogen contributing to peptic inflammation, ulceration, and cancer. A crucial step in the pathogenic sequence is when the bacterium first interacts with gastric tissue, an event that is poorly understood in vivo. We have shown that the luminal space adjacent to gastric epithelial damage is a microenvironment, and we hypothesized that this microenvironment might enhance H. pylori colonization. Inoculation with 106 H. pylori (wild-type Sydney Strain 1, SS1) significantly delayed healing of acetic-acid induced ulcers at Day 1, 7 and 30 post-inoculation, and wild-type SS1 preferentially colonized the ulcerated area compared to uninjured gastric tissue in the same animal at all time points. Gastric resident Lactobacillus spp. did not preferentially colonize ulcerated tissue. To determine whether bacterial motility and chemotaxis are important to ulcer healing and colonization, we analyzed isogenic H. pylori mutants defective in motility (ΔmotB) or chemotaxis (ΔcheY). ΔmotB (106) failed to colonize ulcerated or healthy stomach tissue. ΔcheY (106) colonized both tissues, but without preferential colonization of ulcerated tissue. However, ΔcheY did modestly delay ulcer healing, suggesting that chemotaxis is not required for this process. We used two-photon microscopy to induce microscopic epithelial lesions in vivo, and evaluated accumulation of fluorescently labeled H. pylori at gastric damage sites in the time frame of minutes instead of days. By 5 min after inducing damage, H. pylori SS1 preferentially accumulated at the site of damage and inhibited gastric epithelial restitution. H. pylori ΔcheY modestly accumulated at the gastric surface and inhibited restitution, but did not preferentially accumulate at the injury site. H. pylori ΔmotB neither accumulated at the surface nor inhibited restitution. We conclude that bacterial chemosensing and motility rapidly promote H. pylori colonization of injury sites, and thereby biases the injured tissue towards sustained gastric damage.

Cigarette smoking and gastrointestinal diseases: the causal relationship and underlying molecular mechanisms (review).

Cigarette smoking is an important risk factor for gastrointestinal (GI) disorders, including peptic ulcers, inflammatory bowel diseases, such as Crohn's disease and cancer. In this review, the relationship between smoking and GI disorders and the underlying mechanisms are discussed. It has been demonstrated that cigarette smoking is positively associated with the pathogenesis of peptic ulcers and the delay of ulcer healing. Mechanistic studies have shown that cigarette smoke and its active ingredients can cause mucosal cell death, inhibit cell renewal, decrease blood flow in the GI mucosa and interfere with the mucosal immune system. Cigarette smoking is also an independent risk factor for various types of cancer of the GI tract. In this review, we also summarize the mechanisms through which cigarette smoking induces tumorigenesis and promotes the development of cancer in various sections of the GI tract. These mechanisms include the activation of nicotinic acetylcholine receptors, the formation of DNA adducts, the stimulation of tumor angiogenesis and the modulation of immune responses in the GI mucosa. A full understanding of these pathogenic mechanisms may help us to develop more effective therapies for GI disorders in the future.

Antibiotics and antiseptics for venous leg ulcers.

Antibiotics and antiseptics for venous leg ulcers.

Ulcer healing after peripheral intervention-can we predict it before revascularization?

Complete ulcer healing is one of the most important goals of treatment for critical limb ischemia; however, it is still difficult to inform patients of the time to ulcer healing before performing revascularization. The time to ulcer healing has a great impact on the cost of treatment and patient's quality of life. To predict it, the factors that influence delayed ulcer healing should be explored. According to a review of the literature investigating ulcer healing after revascularization, the influential factors can be classified into 5 categories: (1) systemic factors; (2) clinical state of tissue defect; (3) infection; (4) wound management strategy; and (5) revascularization strategy (endovascular or open repair, the angiosome concept). It is also important to ensure sufficient blood supply to predict ulcer healing probability in the individual patient. Several new methodologies, such as measuring tissue circulation around the tissue defect and intraoperative imaging techniques, have been reported. Because the status of ischemic tissue loss and wound healing ability can affect the decision-making process in selecting the revascularization strategy, understanding the many factors that influence ulcer healing after revascularization is indispensable for physicians performing revascularization. Accumulating ulcer healing data via well-designed clinical research can help to establish a new paradigm for the revascularization strategy from the viewpoint of ulcer healing.

High-Mobility Group Box 1 Inhibits Gastric Ulcer Healing through Toll-Like Receptor 4 and Receptor for Advanced Glycation End Products

High-mobility group box 1 (HMGB1) was initially discovered as a nuclear protein that interacts with DNA as a chromatin-associated non-histone protein to stabilize nucleosomes and to regulate the transcription of many genes in the nucleus. Once leaked or actively secreted into the extracellular environment, HMGB1 activates inflammatory pathways by stimulating multiple receptors, including Toll-like receptor (TLR) 2, TLR4, and receptor for advanced glycation end products (RAGE), leading to tissue injury. Although HMGB1’s ability to induce inflammation has been well documented, no studies have examined the role of HMGB1 in wound healing in the gastrointestinal field. The aim of this study was to evaluate the role of HMGB1 and its receptors in the healing of gastric ulcers. We also investigated which receptor among TLR2, TLR4, or RAGE mediates HMGB1’s effects on ulcer healing. Gastric ulcers were induced by serosal application of acetic acid in mice, and gastric tissues were processed for further evaluation. The induction of ulcer increased the immunohistochemical staining of cytoplasmic HMGB1 and elevated serum HMGB1 levels. Ulcer size, myeloperoxidase (MPO) activity, and the expression of tumor necrosis factor α (TNFα) mRNA peaked on day 4. Intraperitoneal administration of HMGB1 delayed ulcer healing and elevated MPO activity and TNFα expression. In contrast, administration of anti-HMGB1 antibody promoted ulcer healing and reduced MPO activity and TNFα expression. TLR4 and RAGE deficiency enhanced ulcer healing and reduced the level of TNFα, whereas ulcer healing in TLR2 knockout (KO) mice was similar to that in wild-type mice. In TLR4 KO and RAGE KO mice, exogenous HMGB1 did not affect ulcer healing and TNFα expression. Thus, we showed that HMGB1 is a complicating factor in the gastric ulcer healing process, which acts through TLR4 and RAGE to induce excessive inflammatory responses.

Vascular endothelial growth factor receptor 1 signaling facilitates gastric ulcer healing and angiogenesis through the upregulation of epidermal growth factor expression on VEGFR1+CXCR4+ cells recruited from bone marrow

Angiogenesis is essential for gastric ulcer healing. Recent results suggest that vascular endothelial growth factor receptor 1 (VEGFR1), which binds to VEGF, promotes angiogenesis. In the present study, we investigated the role of VEGFR1 signaling in gastric ulcer healing and angiogenesis. Gastric ulcers were induced by serosal application of 100 % acetic acid in wild-type (WT) and tyrosine kinase-deficient VEGFR1 mice (VEGFR1 TK(-/-)). Bone marrow transplantation into irradiated WT mice was carried out using bone marrow cells isolated from WT and VEGFR1 TK(-/-) mice. Ulcer healing was delayed in VEGFR1 TK(-/-) mice compared to WT mice and this was accompanied by decreased angiogenesis, as evidenced by reduced mRNA levels of CD31 and decreased microvessel density. Recruitment of cells expressing VEGFR1 and C-X-C chemokine receptor type 4 (CXCR4) was suppressed and epidermal growth factor (EGF) expression in ulcer granulation tissue was attenuated. Treatment of WT mice with neutralizing antibodies against VEGF or CXCR4 also delayed ulcer healing. In WT mice transplanted with bone marrow cells from VEGFR1 TK(-/-) mice, ulcer healing and angiogenesis were suppressed, and this was associated with reduced recruitment of bone marrow cells to ulcer granulation tissue. VEGFR1 TK(-/-) bone marrow chimeras also exhibited downregulation of EGF expression on CXCR4(+)VEGFR1(+) cells recruited from the bone marrow into ulcer lesions. VEGFR1-mediated signaling plays a critical role in gastric ulcer healing and angiogenesis through enhanced EGF expression on VEGFR1(+)CXCR4(+) cells recruited from the bone marrow into ulcer granulation tissue.

Improving major amputation rates in the multicomplex diabetic foot patient: focus on the severity of peripheral arterial disease

Peripheral arterial disease (PAD), as well as diabetic neuropathy, is a risk factor for the development of diabetic foot ulcers. The aim of this study was to evaluate differences and predictors of outcome parameters in patients with diabetic foot by stratifying these subjects according to the severity of PAD. In a prospective study, patients with new diabetic foot ulcers have been treated and investigated by structured healthcare. Subjects were recruited between 1 January 2000 and 31 December 2007. All study participants underwent a 2-year follow-up observation period. The patients underwent a standardized examination and classification of their foot ulcers according to a modification of the University of Texas Wound Classification System. The severity of PAD was estimated by measurement of the ankle brachial index (ABI) and the continuous wave Doppler flow curve into undisturbed perfusion (0.9 < ABI < 1.3), compensated perfusion (0.5 < ABI < 0.9), decompensated perfusion (ABI < 0.5) and medial arterial calcification. A total of 678 patients with diabetic foot were consecutively included into the study (69% male, mean age 66.3 ± 11.0 years, mean diabetes duration 15.8 ± 10.2 years). Major amputations (above the ankle) were performed in 4.7% of the patients. 22.1% of these subjects had decompensated PAD. These subjects had delayed ulcer healing, higher risk for major amputation [odds ratio (OR) 7.7, 95% confidence interval (CI) 2.8-21.2, p < 0.001] and mortality (OR 4.9, 95 % CI 1.1-22.1, p < 0.05). This prospective study shows that the severity of PAD significantly influences the outcome of diabetic foot ulcers regarding to wound healing, major amputation and mortality.

Sa1868 H. pylori Motility Promotes Preferential Colonization of Ulcerated Tissue in Mouse Stomach

Background: The signals that drive H. pylori to successfully arrive at a colonization niche in gastric tissue are not understood, but are an essential first step for successful colonization, and ultimately the disease consequences of H. pylori infection. We asked if H. pylori can sense gastric ulceration tissue as a stimulus and tissue site to promote colonization, and if early colonization was dependent on the bacterial chemosensing that control flagellar motility. Aim: In the present study, we asked if H. pylori preferentially colonize ulcerated tissue rather than healthy tissue, and further tested colonization and effects on ulcer healing of isogenic bacterial mutants defective in flagellar rotation (motB) or chemotaxis signal transduction (cheY). Methods: Topical application of acetic acid for 20-30 s to the stomach exterior induced an ulcer in anesthetized C57BL/6 mice. A single gavage of 106 -109 H. pylori was performed 2 days after ulcer induction. Ulcer size and number of bacteria colonizing normal and ulcerated stomach tissues were evaluated at 1 or 7 days after gavage. Results: 1 day after 108 inoculation, motile SS1 H. pylori colonized ulcerated corpus/fundus tissue (41.2 x 104 ± 11.9 x 104 CFU/g tissue) more than corresponding healthy tissue in the same stomachs (4.9 x 104 ± 1.9 x 104 CFU/g tissue, n=8, p,0.05). At 7 days, SS1 delayed ulcer healing (1.9 ± 0.6 mm2 ulcer) vs uninfected controls (0.3 ± 0.1 mm2 ulcer, p,0.05), but colonization was no longer different between healthy and ulcerated tissue. After a reduced inoculum (106), SS1 still preferentially colonized ulcerated tissue at 7 days as measured by CFU cultures (intact: 61.6 x 104 ± 28.2 x 104 CFU/g tissue vs ulcerated: 142.5 x 104 ± 46.2 x 104 CFU/g tissue, p,0.05) and real-time PCR of either 16S RNA/cDNA or the ssa gene as H. pylori markers. motB mutant SS1 H. pylori (106) did not colonize (healthy or ulcerated) tissue or delay ulcer healing. motB mutant SS1 H. pylori (108 -109) colonized in both areas (intact: 767.9 ± 896.6 CFU/g tissue vs ulcerated: 823.8 ± 903.4 CFU/g tissue, no significant different) without affecting ulcer healing. In contrast, H. pylori SS1 lacking cheY (106) was competent to colonize stomach tissue. At 7 days, the cheY mutant had delayed ulcer healing, but did not preferentially colonize ulcerated tissue (intact: 12.5 x 104 ± 12.6 x 104 CFU/g tissue vs ulcerated: 13.1 x 104 ± 6.2 x 104 CFU/g tissue, no significant different). Conclusion: H. pylori can rapidly and preferentially colonize sites of ulceration using chemotactic motility and subsequently slow ulcer repair. Lack of non-specific colonization by motB and cheY mutants suggests injury may release chemoattractants that determine the earliest H. pylori motility toward, and interactions with, host tissue.

GM-CSF Produced by Nonhematopoietic Cells Is Required for Early Epithelial Cell Proliferation and Repair of Injured Colonic Mucosa

GM-CSF is a growth factor that promotes the survival and activation of macrophages and granulocytes, as well as dendritic cell differentiation and survival in vitro. The mechanism by which exogenous GM-CSF ameliorates the severity of Crohn's disease in humans and colitis in murine models has mainly been considered to reflect its activity on myeloid cells. We used GM-CSF-deficient (GM-CSF(-/-)) mice to probe the functional role of endogenous host-produced GM-CSF in a colitis model induced after injury to the colon epithelium. Dextran sodium sulfate (DSS), at doses that resulted in little epithelial damage and mucosal ulceration in wild type mice, caused marked colon ulceration and delayed ulcer healing in GM-CSF(-/-) mice. Colon crypt epithelial cell proliferation in vivo was significantly decreased in GM-CSF(-/-) mice at early times after DSS injury. This was paralleled by decreased expression of crypt epithelial cell genes involved in cell cycle, proliferation, and wound healing. Decreased crypt cell proliferation and delayed ulcer healing in GM-CSF(-/-) mice were rescued by exogenous GM-CSF, indicating the lack of a developmental abnormality in the epithelial cell proliferative response in those mice. Nonhematopoietic cells, and not myeloid cells, produced the GM-CSF important for colon epithelial proliferation after DSS-induced injury, as revealed by bone marrow chimera and dendritic cell-depletion experiments, with colon epithelial cells being the cellular source of GM-CSF. Endogenous epithelial cell-produced GM-CSF has a novel nonredundant role in facilitating epithelial cell proliferation and ulcer healing in response to injury of the colon crypt epithelium.

The Interplay Between NSAIDs and Candida albicans on the Gastrointestinal Tract of Guinea Pigs

Recent studies suggest that Candida albicans colonization is associated with several gastrointestinal inflammatory disorders and is also responsible for the delay in ulcer healing. No data are reported about the effects of C. albicans on the nonsteroidal anti-inflammatory drugs (NSAIDs)-induced necroinflammatory lesions. On the other hand, beneficial effects of NSAIDs regarding the colonization potential with C. albicans have been reported. Our aim was to investigate whether the association between NSAIDs and C. albicans could potentially induce necroinflammatory lesions in the guinea pigs gastric and enteral mucosa. Three interventional groups of 11 guinea pigs each were investigated after 5 days of receiving indomethacin, C. albicans or the association of both. C. albicans and necroinflammatory lesions were graded based on histological examinations. Statistical analysis used Mann-Whitney nonparametric test. NSAIDs did not significantly decrease C. albicans colonization grades on gastrointestinal mucosa. Administration of indomethacin subsequent to C. albicans determined significantly more severe necroinflammatory lesions compared to group that only received C. albicans. The association of NSAIDs and C. albicans did not cause significantly more severe degenerative or inflammatory lesions compared to the administration of only NSAIDs in this experimental model. Associations between NSAIDs and C. albicans caused significantly more severe necroinflammatory injuries than the lesions produced by C. albicans, without enhancing the mucosal injury or inflammation caused by NSAIDs.