[Show abstract][Hide abstract] ABSTRACT: Vitamin B deficiencies, which can lead to hyperhomocysteinemia (Hhcy), are commonly reported in patients with inflammatory bowel disease (IBD) and may be a causative underlying factor. However, the mechanism for this effect is not known. Hydrogen sulfide (H 2 S) is a gaseous mediator that promotes tissue repair and resolution of inflammation. In experimental colitis, a marked increase in colonic H 2 S synthesis drives ulcer healing and resolution of inflammation. Because H 2 S synthesis is in part dependent upon enzymes that re-quire vitamin B 6 as a cofactor, we tested the hypothesis that Hhcy in rodent models would increase the susceptibility to colitis. In all three models tested, diet-induced Hhcy significantly exacerbated colitis. The usual elevation of colonic H 2 S synthesis after induction of colitis was absent in all three models of colitis. Administration of an H 2 S donor to Hhcy rats significantly decreased the severity of colitis. Compared with wild-type mice, interleukin (IL) 10-deficient mice on a normal diet had decreased levels of colonic H 2 S synthesis, a 40% increase in serum homocysteine, and a phenotype similar to wild-type mice with Hhcy. IL-10–deficient mice fed the vitamin B-deficient diet exhibited more severe colonic inflammation, but the normal elevation of colonic H 2 S synthesis was absent. Adminis-tration of IL-10 to the IL-10–deficient mice restored colonic H 2 S syn-thesis and significantly decreased serum homocysteine levels. These results suggest that the exacerbation of colitis in Hhcy is due in part to impaired colonic H 2 S synthesis. Moreover, IL-10 plays a novel role in promoting H 2 S production and homocysteine metabolism, which may have therapeutic value in conditions characterized by Hhcy. V itamin deficiencies are commonly reported in patients with inflammatory bowel disease (IBD) and, in most cases, are a consequence of reduced intake or decreased absorption sec-ondary to intestinal injury or surgical resection (1, 2). One of the most common deficiencies in IBD is of vitamin B 6 , affecting up to 30% of patients (3). Vitamin B deficiency can result in ele-vated blood homocysteine levels (hyperhomocysteinemia; Hhcy) (3, 4). Hhcy is associated with increased risk of thrombosis and microvascular disorders (5, 6), as well as with a significant worsening of IBD (1, 7). The mechanisms through which Hhcy exacerbates intestinal inflammation are not known. In recent years, hydrogen sulfide (H 2 S) has become recognized as an important signaling molecule in many organs and tissues (8), and particularly as an anti-inflammatory and cytoprotective mediator (9). H 2 S is produced throughout the gastrointestinal (GI) tract, and its synthesis is markedly increased following mu-cosal injury (10–13). In such settings, H 2 S accelerates repair of damaged tissue and promotes resolution of inflammation (10, 11, 14). Conversely, inhibition of H 2 S synthesis leads to GI mucosal inflammation and impairment of healing of injury (10, 11, 14, 15). There are three enzyme systems for endogenous synthesis of H 2 S, two of which require pyridoxal 5′-phosphate (P5P), the biologically active form of vitamin B 6 , as a cofactor for their activity (8). The two P5P-dependent enzymes for H 2 S synthesis are cystathionine γ-lyase (CSE) and cystathionine β-synthase (CBS). The Hhcy that develops during vitamin B deficiency is in part due to the insufficient conversion of homocysteine to cysteine via P5P-dependent enzymes. This is recapitulated in mice with ge-netic deficiencies of CSE (16) or CBS (17). These mice exhibit el-evated blood levels of homocysteine (but not cysteine). During colitis, the marked elevation of H 2 S synthesis is primarily due to up-regulation of CSE (11, 14). The third key pathway for H 2 S synthesis, which is also up-regulated in colitis (14), involves a P5P-independent enzyme, 3-mercaptopyruvate transferase (3MST) (8). It stands to reason that when levels of vitamin B 6 are di-minished, there may be an impairment of H 2 S synthesis. We hypothesized that Hhcy-related exacerbation of IBD may be a consequence of diminished intestinal production of H 2 S. To test this hypothesis, we examined the effects of diet-induced vi-tamin B deficiency in three models of colitis. One of these models was the interleukin (IL) 10–deficient mouse. In addition to choosing this model because it is a genetic model of colitis, rather than chemical, it is also relevant to the human disease because of established links between IBD and defective IL-10 signaling (18, 19). In the course of our study, we discovered an important regulatory interaction between IL-10 and H 2 S in modulating colonic tissue integrity that appears to be affected by, and be an influence upon, circulating homocysteine levels.
Proceedings of the National Academy of Sciences 09/2014; 111(37):13559-13564. · 9.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Giardia duodenalis (syn. G. intestinalis, G. lamblia) infections are a leading cause of waterborne diarrheal disease that can also result in the development of post-infectious functional gastrointestinal disorders via mechanisms that remain unclear. Parasite numbers exceed 10(6) trophozoites per centimeter of gut at the height of an infection. Yet, the intestinal mucosa of G. duodenalis-infected individuals is devoid of signs of overt inflammation. G. dudoenalis infections can also occur concurrently with other pro-inflammatory gastrointestinal pathogens. Little is known of whether and how this parasite can attenuate host inflammatory responses induced by other pro-inflammatory stimuli, such as a gastrointestinal pathogen. Identifying hitherto unrecognized parasitic immune-modulatory pathways, the present studies demonstrate that G. duodenalis trophozoites attenuate secretion of the potent neutrophil chemoattractant interleukin-8 (CXCL8); these effects were observed in human small intestinal mucosal biopsy tissues, and from intestinal epithelial monolayers, activated through administration of pro-inflammatory interleukin-1β or Salmonella typhimurium. This attenuation is caused by the secretion of G. duodenalis cathepsin B cysteine proteases that degrade CXCL8 post-transcriptionally. Furthermore, the degradation of CXCL8 via G. duodenalis cathepsin B cysteine proteases attenuates CXCL8-induced chemotaxis of human neutrophils. Taken together, these data demonstrate for the first time that G. duodenalis trophozoite cathepsins are capable of attenuating a component of their host's pro-inflammatory response induced by a separate pro-inflammatory stimulus.
Infection and immunity 04/2014; · 4.21 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cannabis is widely used for treating a number of gastrointestinal ailments, but its use is associated with several adverse effects, particularly when the route of administration is via smoking. In the present study, we tested the effects (in rats) of a simple extract of medicinal cannabis (called "MFF") for its ability to promote resolution of colitis, to prevent gastric damage induced by naproxen, and to reduce gastric distention-induced visceral pain. Intracolonic, but not oral administration of MFF dose-dependently reduced the severity of hapten-induced colitis, an effect not reduced by pretreatment with antagonists of CB1 or CB2 receptors. Significant improvement of symptoms (diarrhea, weight loss) and healing of ulcerated tissue was evident with MFF treatment at doses that did not produce detectable urinary levels of 9-Δ-tetrahydrocannabinol (THC). MFF increased colonic hydrogen sulfide synthesis in healthy rats, but not in rats with colitis, and had no effect on colonic prostaglandin E2 synthesis. Orally, but not systemically administered MFF dose-dependently reduced the severity of naproxen-induced gastric damage, and a CB1 antagonist reversed this effect. MFF prevented gastric distention-induced visceral pain via a CB2-dependent mechanism. These results demonstrate that a simple extract of medicinal cannabis can significantly enhance resolution of inflammation and injury, as well as prevent injury, in the gastrointestinal tract. Interestingly, different cannabinoid receptors were involved in some of the effects. MFF may serve as the basis for a simple preparation of cannabis that would produce beneficial effects in the GI tract with reduced systemic toxicity.
Journal of physiology and pharmacology: an official journal of the Polish Physiological Society 04/2013; 64(2):167-75. · 2.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Hydrogen sulfide (H2S) is produced throughout the gastrointestinal tract, and it contributes to maintenance of mucosal integrity, resolution of inflammation, and repair of damaged tissue. H2S synthesis is elevated in inflamed and damaged colonic tissue, but the enzymatic sources of that synthesis are not completely understood. In the present study, the contributions of three enzymatic pathways to colonic H2S synthesis were determined, with tissues taken from healthy rats and rats with colitis. The ability of the colonic tissue to inactivate H2S was also determined. Colonic tissue from rats with hapten-induced colitis produced significantly more H2S than tissue from healthy controls. The largest source of the H2S synthesis was the pathway involving cysteine amino transferase and 3-mercaptopyruvate sulfurtransferase (an α-ketoglutarate-dependent pathway). Elevated H2S synthesis occurred specifically at sites of mucosal ulceration, and was not related to the extent of granulocyte infiltration into the tissue. Inactivation of H2S by colonic tissue occurred rapidly, and was significantly reduced at sites of mucosal ulceration. This correlated with a marked decrease in the expression of sulfide quinone reductase in these regions. Together, the increased production and decreased inactivation of H2S at sites of mucosal ulceration would result in higher H2S levels at these sites, which promotes of resolution of inflammation and repair of damaged tissue.
PLoS ONE 01/2013; 8(8):e71962. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Dextran sulfate sodium is widely used to induce colitis in rodents. Though given orally in drinking water, this agent is widely believed to produce injury through direct toxic effects on the epithelium, and it has been assumed to produce damage and inflammation only in the colon. Given the apparent toxic effects of dextran sodium sulfate on epithelial cells, its administration orally, and the anticoagulant properties of this agent, we hypothesized that significant damage and inflammation would be produced in regions of the digestive tract proximal to the colon. Groups of rats or mice received DSS (5%) in the drinking water for up to 7 days. Tissues were harvested at various time-points for blind evaluation of damage, and measurement of several markers of inflammation. In both rats and mice given DSS, significant damage and inflammation was produced in the stomach, small intestine and colon. Significant granulocyte infiltration was apparent in all tissues by day 3 of DSS ingestion. Bleeding was evident throughout the small intestine and colon. These studies clearly demonstrate that DSS, when administered orally in drinking water, produces a pan-gastroenteritis, rather than the damage and inflammation being limited to the colon. The damage and inflammation in the stomach and small intestine could contribute to changes in body weight, stool consistency and bleeding, all of which are commonly used as indices of severity of colitis. Beneficial or detrimental effects of therapeutic interventions could be attributable, at least in part, to modulation of injury and inflammation proximal to the colon.
Journal of physiology and pharmacology: an official journal of the Polish Physiological Society 10/2012; 63(5):463-9. · 2.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate the relationship between primary afferent neurons, endothelin (ET) and the role of its receptors on ethanol-induced gastric damage in cirrhotic rats.
Cirrhosis and portal hypertension were induced in rats by bile duct ligation (BDL) while controls had a sham operation. The association between ET and afferent neurons on the gastric mucosa was evaluated by capsaicin treatment in newborn rats, the use of ET agonists or antagonists, gastric ET-1 and -3 mRNA and synthetic capacity. Ethanol-induced damage was assessed using ex vivo gastric chamber experiments. Gastric blood flow was measured by laser-Doppler flowmetry.
ET-3 and an ET(B) receptor antagonist significantly reduced the extent of ethanol-induced gastric damage in BDL rats. Gastric ET-1 and -3 levels were 30% higher in BDL rats compared to control rats. Capsaicin treatment restored the gastric resistance and blood flow responses to topical application of ethanol in BDL rats and ET-1 and -3 production to levels observed in controls.
Our results suggest that the reduced resistance of the gastric mucosa of cirrhotic rats to ethanol-induced injury is a phenomenon modulated by ET through the ET(B) receptor and by sensory afferent neurons.
World journal of gastrointestinal pathophysiology. 08/2012; 3(4):85-91.
[Show abstract][Hide abstract] ABSTRACT: One of the characteristics of an active episode of ulcerative colitis (UC) is the intense mucosal infiltration of leukocytes. The pro-resolution mediators Annexin-A1 (AnxA1) and lipoxin A(4) (LXA(4)) exert counter-regulatory effects on leukocyte recruitment, however to date, the dual/cumulative effects of these formyl peptide receptor-2 (FPR2/ALX) agonists in the context of human intestinal diseases are unclear. To define the contribution of these mediators, we measured their expression in biopsies from individuals with UC.
Colonic mucosal biopsies were collected from two broad patient groups: healthy volunteers without ('Ctrl' n = 20) or with a prior history of UC ('hx of UC' n = 5); individuals with UC experiencing active disease ('active' n = 8), or in medically-induced remission ('remission' n = 16). We assessed the mucosal expression of LXA(4), AnxA1, and the FPR2/ALX receptor in each patient group using a combination of fluorescence microscopy, biochemical and molecular analyses.
Mucosal expression of LXA(4) was elevated exclusively in biopsies from individuals in remission (3-fold, P<0.05 vs. Ctrl). Moreover, in this same group we observed an upregulation of AnxA1 protein expression (2.5-fold increase vs. Ctrl, P<.01), concurrent with an increased level of macrophage infiltration, and an elevation in FPR2/ALX mRNA (7-fold increase vs. Ctrl, P<.05). Importantly, AnxA1 expression was not limited to cells infiltrating the lamina propria but was also detected in epithelial cells lining the intestinal crypts.
Our results demonstrate a specific up-regulation of this pro-resolution circuit in individuals in remission from UC, and suggest a significant role for LXA(4) and AnxA1 in promoting mucosal homeostasis.
PLoS ONE 01/2012; 7(6):e39244. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Hydrogen sulfide is emerging as an important mediator of many aspects of inflammation, and perhaps most importantly as a factor promoting the resolution of inflammation and repair of injury. RECENT ADVANCES: In the gastrointestinal tract, H(2)S has been shown to promote healing of ulcers and the resolution of mucosal inflammation. On the other hand, suppression of endogenous H(2)S synthesis impairs mucosal defense and leads to increased granulocyte infiltration. H(2)S has been exploited in the design of more effective and safe anti-inflammatory drugs.
Enteric bacteria can be a significant source of H(2)S, which could affect mucosal integrity; indeed, luminal H(2)S can serve as an alternative to oxygen as a metabolic substrate for mitochondrial respiration in epithelial cells. Enterocytes and colonocytes thereby represent a "metabolic barrier" to the diffusion of bacteria-derived H(2)S into the subepithelial space. A compromise of this barrier could result in modulation of mucosal function and integrity by bacterial H(2)S.
Improvements in methods for measurement of H(2)S and development of more selective inhibitors are crucial for gaining a better understanding of the pathophysiological importance of this mediator. Results from animal studies suggest that H(2)S-releasing agents are promising therapeutic agents for many indications, but these compounds need to be assessed in a clinical setting.
[Show abstract][Hide abstract] ABSTRACT: Many gastrointestinal diseases remain poorly responsive to therapies, and even in the cases of conditions for which there are many effective drugs, there is still considerable room for improvement. This article is focused on drugs for digestive disorders that have entered the marketplace recently, or are expected to reach the marketplace within the next 1 to 2 years. Although advances have been made in understanding gastrointestinal motility, visceral pain, mucosal inflammation, and tissue repair, the major gastrointestinal diseases remain as significant therapeutic challenges.
Gastroenterology clinics of North America 09/2010; 39(3):709-20. · 2.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate the effect of sodium pentobarbitone (SP) or ketamine/xylazine (KX) anesthetics on acute gastric injury.
Portal hypertension was induced by bile duct ligation (BDL) or portal vein stenosis (PVS). Ethanol (EtOH)-induced gastric damage was assessed using ex vivo gastric chamber experiments. Gastric blood flow (GBF) was also measured by laser doppler flowmetry.
EtOH-induced gastric damage was reduced in BDL rats under KX anesthesia in comparison to those under SP anesthesia. GBF dysfunction in fasted BDL rats was partially restored under KX anesthesia. In contrast, in fasted PVS rats, EtOH-induced gastric damage was increased under KX anesthesia while GBF was reduced.
The use of KX anesthesia in experimental procedures involving cirrhotic rats (but not those with pure portal hypertension) is preferable to SP anesthesia.
World journal of gastrointestinal pharmacology and therapeutics. 08/2010; 1(4):81-6.
[Show abstract][Hide abstract] ABSTRACT: Patients with ulcerative colitis (UC) experience unpredictable bouts of active inflammation and ulceration. Relatively little attention has been paid to the role of antiinflammatory mediators in the pathogenesis of UC, although rodent studies suggest an important role of prostaglandin (PG) D(2) in the resolution of tissue injury and inflammation. The present study was performed to determine if colonic PGD(2) synthesis was altered in patients in remission from UC and if expression of the key enzymes and receptors related to PGD(2) was altered. During routine colon-cancer screening, colonic biopsies were obtained from healthy individuals, some of whom had been in remission from UC, without treatment, for >4 y. UC patients with active disease or in medically induced remission were also biopsied. Only patients with active UC exhibited elevated expression of several proinflammatory cytokines (TNFalpha and IFNgamma) and colonic PGE(2) synthesis. In contrast, colonic PGD(2) synthesis was only elevated ( approximately 3-fold) in the healthy individuals with a prior history of UC. This group also exhibited significantly elevated expression of DP1, the key receptor mediating the antiinflammatory actions of PGD(2). Expression of the synthetic enzymes cyclooxygenase-1, cyclooxygenase-2, and hematopoietic PGD synthase was not altered in the healthy individuals with a prior history of UC. These results show a marked up-regulation of synthesis of an antiinflammatory prostanoid and expression of its receptor, specifically in individuals in long-term remission from UC. This is consistent with animal studies showing the importance of PGD(2) in the induction and maintenance of remission from colitis.
Proceedings of the National Academy of Sciences 06/2010; 107(26):12023-7. · 9.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Hydrogen sulphide (H2S) exerts several anti-inflammatory effects, accelerates the healing of experimental gastric ulcers, and can stimulate intestinal secretion. Little is known about H2S synthesis in the gastrointestinal tract. The aim of this study was to characterize H2S synthesis throughout the gastrointestinal tract.
H2S synthesis in various gastrointestinal tissues of rats and mice was determined. The effects and selectivity of inhibitors of two key enzymes for H2S synthesis, cystathionine-gamma-lyase and cystathionine-beta-synthase, were examined. Cystathionine-gamma-lyase and cystathionine-beta-synthase expression was evaluated by Western blotting and immunohistochemistry. Cystathionine-gamma-lyase and cystathionine-beta-synthase expression in biopsies of human colon was also examined.
H2S synthesis was variable throughout the gastrointestinal tract in parallel with variations in cystathionine-gamma-lyase and cystathionine-beta-synthase expression. The efficacy of cystathionine-beta-synthase and cystathionine-gamma-lyase inhibitors to reduce H2S synthesis in these tissues was also variable. Cystathionine-beta-synthase is the predominant source of H2S synthesis in the colon of rodents. Cystathionine-gamma-lyase and cystathionine-beta-synthase were also expressed in healthy human colon biopsies.
The capacity for H2S synthesis varies throughout the rodent gastrointestinal tract, as does the distribution and contribution of the two key enzymes. Investigation of additional enzymatic sources of H2S and the development of more selective inhibitors are suggested.
Digestive and Liver Disease 07/2009; 42(2):103-9. · 3.16 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Portal hypertensive gastropathy (PHG) is often seen in patients with portal hypertension, and can lead to transfusion-dependent anemia as well as acute, life-threatening bleeding episodes. This Review focuses on the mechanisms that underlie the pathogenesis of PHG that provide reasonable grounds for the treatment of this condition, and ultimately enable translation of basic research into clinical practice. Increased portal pressure associated with cirrhosis and liver dysfunction is critical for the development of clinically significant PHG, and leads to impaired gastric mucosal defense mechanisms that render the stomach susceptible to mucosal injury. The use of pharmacological agents such as beta-blockers reduces the frequency of bleeding episodes in PHG. As a last resort, surgical decompression of the portal system, transjugular intrahepatic stent placement and liver transplantation can resolve this condition. Elimination of known risk factors for gastric injury such as alcohol, aspirin and traditional NSAIDs is critical. The role of Helicobacter pylori colonization of the gastric mucosa in PHG is not clear. Careful and critical interpretation of human and experimental data can be helpful to establish a rationale for the medical management of this important condition.
[Show abstract][Hide abstract] ABSTRACT: Primary sensory afferent neurons modulate the hyperdynamic circulation in cirrhotic rats with portal hypertension. The stomach of cirrhotic rats is prone to damage induced by ethanol, a phenomenon associated with reduced gastric hyperemic response to acid-back diffusion. The aim of this study was to examine the impact of ablation of capsaicin-sensitive neurons and the tachykinin NK(1) receptor antagonist A5330 on the susceptibility of the portal hypertensive gastric mucosa to ethanol-induced injury and its effects on gastric cyclooxygenase (COX) and nitric oxide synthase (NOS) mRNA expression. Capsaicin was administered to neonatal, male, Wistar rats and the animals were allowed to grow. Cirrhosis was then induced by bile duct ligation in adult rats while controls had sham operation. Ethanol-induced gastric damage was assessed using ex vivo gastric chamber experiments. Gastric blood flow was measured as well as COX/NOS mRNA expression. Topical application of ethanol produced significant gastric damage in cirrhotic rats compared to controls, which was reversed in capsaicin- and A5330-treated animals. Mean arterial and portal pressure was normalized in capsaicin-treated cirrhotic rats. Capsaicin and A5330 administration restored gastric blood flow responses to topical application of ethanol followed by acid in cirrhotic rats. Differential COX and NOS mRNA expression was noted in bile duct ligated rats relative to controls. Capsaicin treatment significantly modified gastric eNOS/iNOS/COX-2 mRNA expression in cirrhotic rats. Capsaicin-sensitive neurons modulate the susceptibility of the portal hypertensive gastric mucosa to injury induced by ethanol via tachykinin NK(1) receptors and signalling of prostaglandin and NO production/release.
European Journal of Pharmacology 06/2008; 589(1-3):245-50. · 2.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Percutaneous ethanol injection (PEI) is an option for hepatocellular carcinoma (HCC) treatment that is most effective for solitary lesions <or=5 cm or multiple lesions <or=3 cm. Malignant seeding along the needle tract is a rare complication of the procedure. We report a case of tumor seeding along the needle tract following PEI treatment for HCC arising 21 months after treatment.
Journal of Clinical Ultrasound 02/2008; 36(2):105-7. · 0.70 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Mediators involved in the generation of symptoms in patients with irritable bowel syndrome (IBS) are poorly understood. Here we show that colonic biopsy samples from IBS patients release increased levels of proteolytic activity (arginine cleavage) compared to asymptomatic controls. This was dependent on the activation of NF-kappaB. In addition, increased proteolytic activity was measured in vivo, in colonic washes from IBS compared with control patients. Trypsin and tryptase expression and release were increased in colonic biopsies from IBS patients compared with control subjects. Biopsies from IBS patients (but not controls) released mediators that sensitized murine sensory neurons in culture. Sensitization was prevented by a serine protease inhibitor and was absent in neurons lacking functional protease-activated receptor-2 (PAR2). Supernatants from colonic biopsies of IBS patients, but not controls, also caused somatic and visceral hyperalgesia and allodynia in mice, when administered into the colon. These pronociceptive effects were inhibited by serine protease inhibitors and a PAR2 antagonist and were absent in PAR2-deficient mice. Our study establishes that proteases are released in IBS and that they can directly stimulate sensory neurons and generate hypersensitivity symptoms through the activation of PAR2.
Journal of Clinical Investigation 04/2007; 117(3):636-47. · 12.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Eosinophils have been identified in tissues from patients with Crohn's disease (CD) and ulcerative colitis (UC) but whether they contribute to IBD pathogenesis is unknown. This study aimed to investigate the functional activity and morphological aspects of peripheral-blood eosinophils from IBD patients compared to those from healthy volunteers (HVs).
Eosinophils from HVs and CD and UC patients were purified using a Percoll gradient and then a immunomagnetic cell separator. Functional activity in inactivated and previously activated cells was investigated by measuring adhesion to fibronectin and chemotaxis to fMLP, and degranulation was measured by release of eosinophil peroxidase (EPO). Cell morphology was investigated using electron microscopy.
Eosinophil adhesion to human fibronectin in both inactivated and PAF-stimulated and PMA-stimulated eosinophils was markedly higher in patients with CD than in either patients with UC or HVs. Similarly, the chemotactic response was markedly higher in eosinophils isolated from CD patients than in those isolated from UC patients or HVs. Baseline EPO release was higher in eosinophils isolated from UC patients than in those isolated from HVs or CD patients. Stimulation with fMLP or PMA did not further increase EPO release in cells from UC or CD patients. Comparable expression of MAC- 1 and VLA-4 adhesion molecules was observed on the surfaces of eosinophils from all groups, and an greater number of granules was noted in the eosinophils from UC patients than in those from CD patients.
Our results indicate that peripheral-blood eosinophils are potentially primed and activated in IBD patients. Whether the differences in the morphology and functional responses of eosinophil from UC and CD patients reflect differences in disease phenotype remains to be elucidated.