Labelled leucocyte scintigraphy in inflammatory bowel disease: clinical applications

Extracellular vesicles as a platform for membrane-associated therapeutic protein delivery

Membrane proteins are of great research interest, particularly because they are rich in targets for therapeutic application. The suitability of various membrane proteins as targets for therapeutic formulations, such as drugs or antibodies, has been studied in preclinical and clinical studies. For therapeutic application, however, a protein must be expressed and purified in as close to its native conformation as possible. This has proven difficult for membrane proteins, as their native conformation requires the association with an appropriate cellular membrane. One solution to this problem is to use extracellular vesicles as a display platform. Exosomes and microvesicles are membranous extracellular vesicles that are released from most cells. Their membranes may provide a favourable microenvironment for membrane proteins to take on their proper conformation, activity, and membrane distribution; moreover, membrane proteins can cluster into microdomains on the surface of extracellular vesicles following their biogenesis. In this review, we survey the state-of-the-art of extracellular vesicle (exosome and small-sized microvesicle)-based therapeutics, evaluate the current biological understanding of these formulations, and forecast the technical advances that will be needed to continue driving the development of membrane protein therapeutics.

Urinary potassium is a potential biomarker of disease activity in Ulcerative colitis and displays in vitro immunotolerant role

We evaluated the in-vitro effect of potassium on CD4⁺ T cells and the role of urinary potassium as a potential biomarker of disease activity in patients with ulcerative colitis (UC). This prospective observational cohort study included healthy controls (n = 18) and UC patients [n = 30, median age: 40 (IQR: 28–46) years, 17 males)] with active disease(assessed by Mayo score) from September 2015–May 2016. Twenty-four hours urinary potassium along with fecal calprotectin (FCP) were estimated in UC patients (at baseline and follow-up after 3–6 months) and controls. In healthy volunteers, we also assessed the effect of potassium on CD4⁺ T cells differentiated in the presence of Th17 polarizing condition. UC patients had significantly higher FCP (368.2 ± 443.04 vs 12.44 ± 27.51, p < 0.001) and significantly lower urinary potassium (26.6 ± 16.9 vs 46.89 ± 35.91, p = 0.01) levels than controls. At follow-up, a significant increase in urinary potassium among patients who had clinical response [n = 22, 21.4 (14.4–39.7) to 36.5 (20.5–61.6), p = 0.04] and remission [n = 12, 18.7 (9.1–34.3) to 36.5 (23.4–70.5), p = 0.05] was accompanied with a parallel decline in FCP. On in-vitro analysis, potassium under Th17 polarizing conditions significantly inhibited IL-17 and interferon-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\gamma $$\end{document}γ expression while favoring the induction of FoxP3⁺ T cells. Therefore, urinary potassium levels are inversely associated with disease activity in UC with in-vitro data supporting an immune-tolerant role of potassium.

Role of computed tomography enterography/magnetic resonance enterography: is it in prime time?

Today, cross-sectional imaging modalities, such as computed tomography enterography (CTE) and magnetic resonance enterography (MRE), are particularly suited to evaluate small bowel diseases, especially Crohn's disease (CD). It is well known that CTE/MRE can provide excellent assessment of disease activity as well as the macroscopic features, extramural abnormalities, and complications of the small intestine in patients with CD. In general, CTE is considered as the first-line modality for the evaluation of suspected inflammatory bowel disease and for long-term assessment or follow-up of these patients. Because of the advantage of lack of radiation, MRE is being used more frequently, especially in children or young patients with CD.

A look into the small bowel in Crohn's disease

Crohn's disease (CD) is an inflammatory bowel disease that can affect the entire gastrointestinal tract, with the small bowel (SB) being the most commonly affected site. In some patients, refractory inflammation or chronic strictures of the SB are responsible for a debilitating course of the disease that might lead to severely reduced quality of life. Therefore, SB imaging is a crucial element in diagnosing and/or managing SB CD, and continues to evolve because of technologic advances. SB endoscopy (capsule endoscopy and device-assisted enteroscopy) and cross-sectional radiologic imaging (computed tomography enterography and magnetic resonance enterography) have become key players to diagnose and/or manage CD. In everyday practice, the choice of the imaging modalities is based on the presence and availability of the techniques and of experienced operators in each institute, clinical usefulness, safety, and cost. Here, SB endoscopy and radiologic imaging in suspected or known CD patients will be addressed and discussed.

Non-invasive diagnosis and grading of postsurgical endoscopic recurrence in Crohn's disease: usefulness of abdominal ultrasonography and (99m)Tc-hexamethylpropylene amineoxime-labelled leucocyte scintigraphy

Non-invasive techniques aim to be an alternative to endoscopy in the assessment of postsurgical recurrence of Crohn's disease (CD). The object of this study was to evaluate the accuracy of abdominal ultrasonography (AUS) and (99m)Tc-hexamethylpropylene amineoxime ((99m)Tc-HMPAO)-labelled leucocyte scintigraphy (LLS) compared with endoscopy in the diagnosis and grading of postsurgical recurrence of CD. Between January 2006 and May 2007, all patients with CD and resection with ileocolic anastomosis were included prospectively. Within three days they underwent an ileocolonoscopy, AUS with evaluation of bowel wall thickness and the presence of Doppler flow, and LLS. Forty patients who met the study conditions were included; 5 patients did not agree to have the ileocolonoscopy and it was not possible to assess the anastomosis in 2 patients. Endoscopic recurrence was detected in 26 patients (78.8%), in 15 of whom it was moderate-severe. For the diagnosis of recurrence, both AUS and LLS showed acceptable sensitivity and positive predictive value, with an accuracy of 72.7% and 78.1%, respectively. The results of the AUS and LLS for diagnosing moderate-severe recurrence were better, with an accuracy of 78.8% and 81.3%, respectively. The best assessment of the severity of the recurrence was obtained with the combination of both techniques (sensitivity, specificity, positive and negative predictive values, accuracy and kappa index were, respectively: 93.3%, 72.2%, 73.7%, 92.9%, 81.8% and 0.64). The variables evaluated, both sonographic and scintigraphic, had areas under the curve that were similar and significantly different from 0.5.

CONCLUSION

Abdominal ultrasonography and (99m)Tc-HMPAO-labelled leucocyte scintigraphy are two useful non-invasive techniques for the assessment of postsurgical recurrence of Crohn's disease.

Role of MRI in Crohn's disease

The traditional imaging of Crohn's disease has relied on barium and computed tomography (CT) examinations. In recent years magnetic resonance imaging (MRI) has emerged as an imaging method that can be used in the diagnosis and assessment of Crohn's disease. The advantages of MRI include lack of ionizing radiation and its superior tissue contrast resolution. The clinical progression of Crohn's disease can be variable, and MRI can be used to assess inflammatory status, disease progression, and complications of Crohn's disease. MRI of the small bowel is an evolving technique and it has the potential to become the preferred technique for imaging of small bowel Crohn's disease in the future.

Technetium-99m hexamethyl propylene amine oxime-labeled leukocyte scintigraphy at three different times in active ulcerative colitis: comparison with colonoscopy and clinico-biochemical parameters in the assessment of disease extension and severity

OBJECTIVE

In this study, our objective was to define the usefulness of technetium-99m hexamethyl propylene amine oxime (Tc-99m HMPAO)-labeled leukocyte scintigraphy at three different time points in the assessment of disease extension and severity in patients with active ulcerative colitis (UC).

METHODS

Twenty-one consecutive patients (10 women, 11 men; mean age 42.4 +/- 12 years) with active UC were prospectively studied. All patients were diagnosed by colonoscopy and histopathology prior to inclusion. Scintigraphy was performed at 1 h, 2 h, and 4 h after Tc-99m HMPAO-labeled leukocyte injection. Clinic-biochemical activity score, total colonoscopic activity score, and total scintigraphic activity score at 1 h, 2 h, and 4 h were calculated for each patient.

RESULTS

Sensitivity, specificity, and accuracy values of Tc-99m HMPAO-labeled leukocyte scintigraphy were calculated as follows, respectively: 1 h imaging 86%, 73%, and 83%; 2 h imaging 89%, 74%, and 86%; 4 h imaging 90%, 58%, and 83% in the detection of active inflammatory segments. Even though no statistically significant difference was found between 1 h, 2 h, and 4 h imaging with respect to the sensitivity, specificity of labeled leukocyte scintigraphy, the largest area under the curve value was found for 2 h imaging.

CONCLUSIONS

Tc-99m HMPAO-labeled leukocyte scintigraphy has been found to be correlated well with colonoscopy in the assessment of both the extension and severity of UC. We recommend 2 h scintigraphic imaging because it provides the largest area under the curve value and decreases the number of false-positive results.

Crohn's disease and its mucocutaneous involvement

Crohn's disease (CD) is a chronic inflammatory disorder primarily affecting the lower gastrointestinal tract but potentially involving the skin, musculoskeletal system, and eyes. The origin remains unknown, although diverse etiologic agents have been proposed. Characteristic pathologic appearances include the formation of "skip" lesions (discrete regions of inflamed bowel separated by uninvolved mucosae), aphthous ulceration, and fistulation; these signs relate to the presence of an underlying granulomatous transmural inflammation. Cutaneous and oral lesions frequently occur in CD. They may be classified as specific manifestations (in particular, perianal fissures, abscesses, sinuses, and fistulae in ano) with a granulomatous noncaseating inflammation on histologic examination, and nonspecific manifestations (eg, erythema nodosum, neutrophilic dermatoses) with a nonspecific histologic pattern. The diagnosis of CD is based on clinical, endoscopic, radiologic, and histopathologic features. Therapy is mainly aimed at the control of the acute disease and prevention of relapse through the use of mesalazine, corticosteroids, immunosuppressive agents and very recently, anti-tumor necrosis factor-alpha antibodies.

Pediatric Gastrointestinal Nuclear Medicine

General localization of gastrointestinal bleeding through the use of labeled red blood cells may be performed in children, or (99m)Tc-pertechnetate may be used if a Meckel's diverticulum is suspected. As in adults, cholecystitis and biliary leak may be assessed in children via (99m)Tc-IDA derivatives. Gastroesophageal reflux can be evaluated by oral consumption of the child's usual diet labeled with (99m)Tc sulfur colloid. For the scintigraphic determination of pulmonary aspiration, a relatively high concentration of tracer within a drop of liquid is placed beneath the child's tongue followed by dynamic imaging of the respiratory tract. Colonic transit scintigraphy can aid in the identification and therapeutic decision-making in patients with functional fecal retention, the most common cause of chronic constipation in children. (18)F-DOPA positron emission tomography is useful for classifying pancreatic involvement in infantile hyperinsulinism as focal or diffuse, thereby differentiating between patients who should receive curative focal pancreatic resection versus those who should receive medical management. Assessment of protein-losing enteropathy can be conducted scintigraphically and, compared with fecal alpha-1 antitrypsin collection, the scintigraphic method can detect esophageal and gastric protein loss. Also, scintigraphic quantification of protein loss can be performed without the requirement for fecal collection. Intestinal inflammation in children with inflammatory bowel disease can be evaluated using (99m)Tc white blood cells. The scintigraphic method is safe, accurate, well-tolerated by children and complementary to endoscopy in most patients.

Leukocyte scintigraphy compared to intraoperative small bowel enteroscopy and laparotomy findings in Crohn's disease

BACKGROUND

Leukocyte scintigraphy is a noninvasive investigation to assess inflammation. We evaluated the utility of labeled leukocytes to detect small bowel inflammation and disease complications in Crohn's disease and compared it to whole small bowel enteroscopy and laparotomy findings.

METHODS

Scintigraphy with technetium-99m exametazime-labeled leukocytes was prospectively performed in 48 patients with Crohn's disease a few days before laparotomy; 41 also had an intraoperative small bowel enteroscopy. The same procedures were performed in 8 control patients. Independent grading of scans was compared with the results of enteroscopy and with surgical, histopathologic, and clinical data.

RESULTS

In the 8 control patients leukocyte scan, endoscopy, and histopathology were all negative for the small bowel. In patients with Crohn's disease and small bowel inflammation seen at enteroscopy and/or laparotomy (n = 39) the scan was positive in 33. In 8 patients without macroscopic small bowel inflammation, the scan was positive for the small bowel in 3 patients; at histology, 2 of 3 had inflammation. When combining results for patients and controls, the sensitivity of leukocyte scan for macroscopically evident small bowel inflammation was 0.85, specificity 0.81, accuracy 0.84, positive predictive value 0.92, and negative predictive value 0.68. Scintigraphy detected inflammatory lesions not known before laparotomy in 16 of 47 (34%) Crohn's disease patients and showed uptake in 25 of 35 (71%) bowel strictures. It was diagnostic regarding 4 of 8 abscesses and 9 of 15 fistulas. In 6 patients (13%) lesions first demonstrated by leukocyte scintigraphy were treated during the surgery performed.

CONCLUSIONS

Leukocyte scintigraphy reliably detects small bowel inflammation in Crohn's disease. It gives additional information on the presence of inflammatory lesions in a fraction of patients planned for surgery.

99mTc-hexamethylpropylene amineoxime leukocyte scintigraphy in acute pancreatitis: an alternative to contrast-enhanced computed tomography?

OBJECTIVE

Contrast-enhanced computed tomography (CECT) is the most efficient imaging technique for the diagnosis and staging of acute pancreatitis (AP); its use, however, may be unfeasible in some patients as a consequence of the drawbacks of intravenous (IV) contrast material. The aim of this study was to test the utility of labeled leukocyte scintigraphy (LLS) as an alternative imaging technique to CECT for the staging of AP.

METHODS

Sixty-six patients with AP were prospectively studied. All patients underwent CECT and pancreatic LLS using (99m)Tc-hexamethylpropylene amineoxime as leukocyte label within a time interval of 2 days, in the early phase of AP. In addition, all patients had their serum C-reactive protein (CRP) concentration measured within 48-72 h after admission. CECT images were analyzed for Balthazar's grade of pancreatitis and for the presence or absence of pancreatic necrosis. Scintigraphic activity of 3-4 h planar images was scored on a 0-2 scale in relation to physiological liver uptake.

RESULTS

LLS score was significantly related (p < 0.001) to both components of CECT (grade of pancreatitis and pancreatic necrosis). LLS and serum CRP showed similar results for detecting the most severe pancreatic damage as showed by their respective receiver operating characteristic (ROC) curves. Sensitivities and specificities of LLS score of 2 were, respectively, 62% and 96% for the detection of grade D-E pancreatitis and 90% and 89% for the detection of pancreatic necrosis. Scintigraphic score of 2 increased the likelihood of grade D-E pancreatitis from 32% (pretest probability) to 87% (posttest probability) (likelihood ratio: 13.9) and that of pancreatic necrosis from 16% to 60% (likelihood ratio: 8.4).

CONCLUSIONS

Our results show that leukocytes are related to the severity of local pancreatic damage in AP. Thus, LLS is a potential alternative technique to CECT for staging AP.

Is scintigraphic double-track appearance a sign of severe acute episodes of ulcerative colitis?

AIM

In comparison to endoscopy, clinical and biological criteria are less predictive of severity in attacks of ulcerative colitis (UC). Our aim was to assess the value of the double-track scintigraphic appearance in the assessment of the severity of acute UC by comparing it to endoscopic criteria.

PATIENTS AND METHODS

We reviewed medical records of 52 patients hospitalized for an acute attack of UC, who had undergone within 48 hours of presentation both a technetium 99m hexamethyl propylene amine oxime (99mTc-HMPAO) granulocyte scintigraphy and endoscopic examination (colonoscopy: n=20; rectosigmoidoscopy: n=32).

RESULTS

Taking into account the colonic segments examined together with both methods in the same patient or results obtained with colonoscopies, there was an excellent agreement between the double-track scintigraphic appearance and endoscopic criteria of severity.

CONCLUSION

In patients with previously diagnosed UC, 99mTc-HMPAO granulocyte scintigraphy when available may replace endoscopic examination to assess the severity of attacks.

Evaluation of 99mTc-HMPAO leukocyte scintigraphy in the investigation of pediatric inflammatory bowel disease

OBJECTIVE

To evaluate (99m)Tc-HMPAO leukocyte scintigraphy as an investigation for inflammatory bowel disease (IBD).

STUDY DESIGN

Scintigraphy was performed in 95 children undergoing investigation for IBD in a tertiary Gastroenterology Department. Diagnosis was based on conventional investigations including small bowel barium contrast radiology (BCR), upper gastrointestinal endoscopy (UGIE), colonoscopy, and endoscopic biopsy (the "gold standards"). IBD was confirmed in 73 (57 Crohn's disease; 10 ulcerative colitis; 6 indeterminate colitis) and excluded in 22 (controls). Scintigraphy was (1) evaluated as a screening test, (2) compared with individual conventional tests, (3) assessed for each gut segment.

RESULTS

Screening test: sensitivity 0.75 (95% CI, 0.63-0.85), specificity 0.82 (95% CI, 0.59-0.94), PPV 0.93, NPV 0.5. Comparison with BCR: sensitivity 0.87 (95% CI, 0.72-0.96), specificity 0.57 (95% CI, 0.39-0.73), PPV 0.69, NPV 0.2. Comparison with UGIE: specificity 0.9 (95% CI, 0.79-0.96), NPV 0.13 (sensitivity and PPV unavailable). Comparison with colonoscopy: sensitivity 0.57 (95% CI, 0.41-0.73), specificity 0.71 (95% CI, 0.54-0.85), PPV 0.71, NPV 0.42. Comparison with biopsies paralleled that with endoscopy. False negatives were especially common (NPV< or =0.2) in the proximal gut.

CONCLUSIONS

(99m)Tc-HMPAO leukocyte scintigraphy should not be relied on as a screening test for IBD because false negative results are common. This method is especially unreliable at detecting disease in the proximal gut.

Faecal calprotectin: a marker of inflammation throughout the intestinal tract

OBJECTIVE

To assess the potential of measuring the calcium-binding protein calprotectin in faeces as a method of screening for alimentary inflammation and neoplasia.

SETTING

Hospital day services unit for endoscopy and faecal analysis in the clinical biochemistry department.

PARTICIPANTS

Consented patients attending for routine endoscopy were requested to provide faeces. Seventeen of the initial 30 patients provided faeces before and 1 week after endoscopy. After this, 116 patients for planned endoscopy provided faeces before endoscopy. The group comprised 43 patients with upper-gastrointestinal lesions, seven patients with inflammatory bowel disease, seven patients with irritable bowel syndrome, 31 patients with colonic disorders, and 28 normal people. A final 18 patients with known inflammatory bowel disease (seven patients), gastric carcinoma (one patient), colorectal cancer (eight patients) and colorectal adenoma (two patients) had faeces analysed.

METHOD

Faeces were analysed by the Nycotest PhiCal enzyme-linked immunosorbent assay (ELISA) (Nycomed, Oslo, Norway), and the final 18 patients were analysed by the newer version marketed as Calprest.

RESULTS

No definite differences between pre- and post-endoscopy calprotectin were found, but it was considered preferable in the subsequent patients to analyse pre-endoscopy faeces. Upper-gastrointestinal disorders showed little difference in calprotectin levels, Barrett's oesophagus (median 6.8 mg/l), gastric ulcer (median 6.5 mg/l) or gastritis/duodenitis (median 5.2 mg/l), but these levels were all higher than the median calprotectin level of normal subjects (4.5 mg/l). The oesophageal and gastric carcinoma median was elevated significantly at 30 mg/l. Inflammatory bowel disease was also associated with marked elevation (Crohn's disease, 31.2 mg/l; ulcerative colitis, 116.2 mg/l). Colorectal polyps (median 3.7 mg/l) and adenoma (median 3.8 mg/l) showed no elevated levels in contrast to colorectal carcinoma (median 53.4 mg/l). The elevated calprotectin in inflammatory bowel disease and colorectal carcinoma combined gave a sensitivity of 81.8% and a specificity of 73.2%.

CONCLUSIONS

Calprotectin levels are elevated in inflammation and cancer but are not helpful in differentiating between these disorders. In our series, calprotectin was not elevated in colonic polyps or adenomata. Calprotectin could be helpful as a screening method in a general gastroenterology population for inflammatory bowel disease and those with carcinoma, as well as assessing and monitoring disease activity in inflammatory bowel disease.

Abdominal scintigraphy using technetium Tc 99m hexylmethylpropylene amine oxime-labeled leukocytes in patients with seronegative spondyloarthropathies

OBJECTIVE

To assess the potential benefits of technetium Tc 99m hexylmethylpropylene amine oxime (Tc 99m HMPAO)-labeled leukocyte scintigraphy in a group of patients with spondyloarthropathies (SpAs), overt gastrointestinal symptoms, and negative extensive endoscopic/radiologic test results.

PATIENTS AND METHODS

Ten patients with SpAs and overt gastrointestinal symptoms were included in this study. All patients underwent colonoscopy and small bowel barium studies, and results were negative. Abdominal scintigraphy with Tc 99m HMPAO-labeled leukocytes was performed in all the patients. Clinical and laboratory data and response to treatment was recorded.

RESULTS

The Tc 99m HMPAO-labeled leukocyte scintigraphy was positive in 5 of 10 patients, demonstrating uptake at the terminal ileum which is very suggestive of Crohn disease. The 5 scintigraphically positive patients were treated with sulfasalazine (SSZ). Four patients responded to SSZ with significant improvement of both gastrointestinal and joint symptoms.

CONCLUSIONS

In 5 of 10 patients with SpA and suspected inflammatory bowel disease on clinical grounds, evidence of inflammatory bowel disease was shown by scintigraphic studies in which conventional invasive procedures failed. Tc 99m HMPAO-labeled leukocyte scintigraphy should be considered in the evaluation of patients with SpA.

99mTc-HMPAO leucocyte scintigraphy fails to detect Crohn's disease in the proximal gastrointestinal tract

OBJECTIVE

To investigate the use of (99m)Tc-HMPAO (hexamethyl propylene amine oxime) leucocyte scintigraphy as a non-invasive screening test for inflammatory bowel disease.

PATIENTS

10 children with suspected Crohn's disease, in whom routine investigation using barium contrast radiology, upper gastrointestinal endoscopy, colonoscopy, and mucosal biopsies had identified severe gastroduodenal and/or jejunal involvement.

DESIGN

(99m)Tc-HMPAO leucocyte scintigraphic studies performed in each of these cases were assessed by a radiologist who was blinded to the disease distribution.

RESULTS

In nine cases there was no scintigraphic evidence of inflammation in the proximal gastrointestinal tract. The 10th child had both gastroduodenal and jejunal involvement, but scintigraphy only revealed faint jejunal positivity.

CONCLUSIONS

(99m)Tc-HMPAO leucocyte scintigraphy should not be depended upon as a screening test for Crohn's disease. False negative results are likely in cases with Crohn's disease confined to the proximal gastrointestinal tract.

Modulating the fibrinolytic system of peripheral blood mononuclear cells with adenovirus

Gene therapy utilizing leukocytes is an unexplored therapeutic strategy for targeting tissue-type plasminogen activator (t-PA) to fibrin and sites of inflammation. In this study, five cationic lipids were observed to enhance the adenovirus (Ad)-mediated expression of t-PA in human peripheral blood mononuclear cells (PBMCs) in a dose-dependent manner between 1000 and 15,000 lipid molecules per Ad particle (efficiency:LipofectAMINE > GenePORTER > Effectene > SuperFect > DMRIE-C). PBMCs treated with Ad/t-PA * LipofectAMINE complexes displayed elevated t-PA expression over a 4-day period and the t-PA-expressing cells facilitated the lysis of plasma clots in vitro. Functional and immunologic assays revealed that the Ad * LipofectAMINE infection protocol did not affect monocyte adhesion in vitro or elevate the expression of procoagulant activity, interleukin 8, or tumor necrosis factor alpha. The potential of this system was documented with an in vivo rat model system that involved the injection of lipopolysaccharide into the peritoneal cavity to induce an inflammatory response. Infusion of Ad/t-PA-infected rat PBMCs into the vasculature of lipopolysaccharide-treated animals was found to increase local fibrinolytic activity by 4-fold. These data provide a framework for utilizing adenovirus to transfer genes into PBMCs.

Tc-99m HMPAO white blood cell scintigraphy in the assessment of the extent and severity of an acute exacerbation of ulcerative colitis

PURPOSE

Ulcerative colitis (UC) is a chronic inflammatory bowel disease with frequent exacerbations, including the risk for toxic megacolon and severe complications. In very active disease, colonoscopy should not be performed to assess the severity and the extent of the disease. The aim of the current study was to determine whether Tc-99m HMPAO-labeled white blood cell (WBC) scintigraphy can be used as an alternative to colonoscopy to determine the extent and the severity of the disease in critically ill patients.

METHODS

Twenty consecutive patients (7 women, 13 men; age 38.1 +/- 13.1 years) who had a severe attack of UC underwent scintigraphy on the day of admission. Leukocytes were labeled with 200 MBq (5.35 mCi) Tc-99m HMPAO. Planar anterior and posterior imaging of the abdomen was performed 45 and 120 minutes after WBC reinjection. The tracer uptake in the different colon segments was scored visually compared with bone marrow uptake. A symptom score was made and C-reactive protein was measured as a serologic marker of inflammation. Rectosigmoidoscopy with biopsy was performed within 24 hours of scintigraphy. Scintigraphic, endoscopic, and histologic results were compared for disease activity.

RESULTS

The mean symptom score was 12.7 (+/-0.7) on a scale of 21, and mean the C-reactive protein level was 6.8 (+/-1.2) mg/l. No significant difference was found between the scintigraphic score of the rectum and the endoscopic or the histologic score. The best correlation was found with the latter (r = 0.66, P < 0.01). Based on the results of scintigraphy, disease involved the left side of the colon up to the splenic flexure in 10 patients. The other patients had pancolitis.

CONCLUSIONS

Disease severity can be determined adequately by planar WBC scintigraphy in patients with severe attacks of UC. Because the presence and severity of disease correlates well with endoscopic and histologic findings, WBC scintigraphy can assess disease extent without the need for colonoscopy. This decreases the number and severity of complications that can occur in already critically ill patients.

123Iodine-labelled anti-VCAM-1 antibody scintigraphy in the assessment of experimental colitis

OBJECTIVES

To evaluate the usefulness of 123I-labelled anti-vascular cell adhesion molecule-1 (VCAM-1) monoclonal antibody (MAb) scintigraphy in the assessment of colonic inflammatory damage.

DESIGN

Colitis was induced by intracolonic administration of 30 mg trinitrobenzenesulphonic acid in 0.5 ml of 50% (v/v) ethanol. Rats injected with vehicle served as controls. Animals were studied at day 7 after induction of colitis.

METHODS

Scintigraphy was performed in control and trinitrobenzenesulphonic acid-induced colitic rats 2, 4 and 24 h after intravenous administration of 123I-anti-VCAM-1 MAb. Scintigraphic uptake was quantified in selected areas on scintigraphs. Animals were killed, tissue 123I radioactivity accumulation was measured, and accumulation of anti-VCAM-1 MAb in each organ was calculated. 99mTc-hexamethyl propylene amine oxime-labelled leucocyte scintigraphy was performed in additional groups of animals for comparison.

RESULTS

Colonic tracer uptake was visible in scans of colitic, but not control animals. Quantification of scintigraphic uptake in the colon was significantly higher in colitic rats than in control animals (P< 0.0001). The specificity of the increase was demonstrated by lack of 123I-labelled non-binding MAb uptake in the colon, and by displacement of 123I-anti-VCAM-1 MAb colonic uptake by pre-treatment with unlabelled MAb. Accumulation of anti-VCAM-1 MAb in the colon of colitic rats was eightfold higher than in control animals. Strong correlations were found between quantification of scintigraphic uptake, anti-VCAM-1 MAb accumulation, histological damage and myeloperoxidase activity in the colon.

CONCLUSION

123I-labelled anti-VCAM-1 MAb scintigraphy allows an accurate evaluation of colonic inflammatory damage in trinitrobenzenesulphonic acid-induced colitis, suggesting a potential role for this imaging technique in the assessment of human IBD.

The role of nuclear medicine in inflammatory bowel disease. A review with experiences of aspecific bowel activity using immunoscintigraphy with 99mTc anti-granulocyte antibodies

The diagnosis of inflammatory bowel disease (IBD) needs a complex diagnostic work-up. Beside verifying the disease itself, it is fundamental to assess disease extent and activity and to detect associated complications, to find the most effective treatment and for follow up. Scintigraphy with radiolabelled leukocytes is able to provide a complete survey of the whole intestinal tract, both the small and large bowel, and detects septic complications successfully with negligible risk. Radionuclide procedures are useful in establishing or ruling out IBD in patients with intestinal complaints, in assessing disease severity, and in the evaluation of extraintestinal septic complications. Widely available radionuclide procedures are discussed, i.e. scintigraphy by 111Indium oxime or 99mTechnetium HMPAO labelled white blood cells and immunoscintigraphy with 99mTc anti-granulocyte antibodies. Advantages and disadvantages of all three methods are stressed out.

PATIENTS AND METHODS

The immunoscintigraphies with 99mTc anti-granulocyte antibodies (ANTI-GRANULOCYTE(R) BW 250/183) of 27 patients with suspicion of IBD were retrospectively analysed. Planar anterior and posterior images were obtained 4 and 24 h postinjection, respectively. The bowel was divided into six segments and the activity was visually graded with reference to bone marrow in each segments. The scans were compared with the results of radiological and endoscopical investigations. The diagnosis of IBD was proved or ruled out by means of enteroclysis, large bowel enema or endoscopy.

RESULTS

In the 27 patients, 74 bowel segments with increased activity were detected. In the case of 30 segments in 16 patients, bowel inflammation was revealed by the other methods (true positives). In the case of 44 bowel segments, no underlying bowel inflammation could be verified, and these activities were regarded as aspecific activity. We could not differentiate between true positive and aspecific activity based on scan pattern or intensity.

DISCUSSION

These findings of aspecific bowel activity using imuunoscintigraphy are in contrast with the results of former studies, while the existence of non-specific activity decreases the reliability of the method. Based on the literature and our experiences, we conclude that 99mTc HMPAO labelling should be the method of choice for the investigation of IBD patients.

Pediatric inflammatory bowel disease imaged with Tc-99m white blood cells

Studies have suggested that Tc-99m white blood cell (WBC) imaging is superior to contrast radiology for assessing the extent and activity of inflammatory bowel disease (IBD). The Tc-99m WBC scan seems ideally suited to obtain, in only one examination, a precise temporal snapshot of the distribution and intensity of inflammation, whereas radiographic methods of investigation tend to represent changes that are more chronic. The test is useful in children with inconspicuous signs suggesting IBD in whom laboratory test results are either normal or slightly abnormal. In those cases, a negative Tc-99m WBC study will obviate endoscopic investigations. The author's current experience, in more than 500 patients, indicates that the Tc-99m WBC scan is a virtual gold standard to establish, or exclude, the diagnosis of IBD. The minimal invasiveness of the Tc-99m WBC scan makes it an especially attractive method for evaluating children with IBD. It is economical compared with endoscopy, and its diagnostic sensitivity is excellent. The ability to evaluate the small and large bowel simultaneously is an important advantage for the patient. In conclusion, the Tc-99m WBC scan is a useful tool to evaluate IBD and should be added to the clinician's investigative armamentarium.

Polymeric versus elemental diet as primary treatment in active Crohn's disease: a randomized, double-blind trial

OBJECTIVE

Enteral feeding is now an established primary therapy for active Crohn's disease. This first-double blind randomized trial was designed to compare the therapeutic efficacy of a polymeric diet (PD) with an elemental diet (ED).

METHODS

Patients with active Crohn's disease (Crohn's disease activity index [CDAI] > 150, increased bowel uptake of Tc-HMPAO-labeled leukocytes, and abnormal C-reactive protein [CRP]), were randomized to receive either an ED or a PD. The two preparations were identical except for the nitrogen source, which was amino acid based in ED and intact protein in PD. Enteral feeding was considered successful if clinical remission was achieved as defined by a final CDAI of < or = 150, a reduction in the CDAI by at least 100 points from baseline level, and a normal CRP.

RESULTS

Twenty-one patients were enrolled of whom 11 were randomized to PD and 10 to ED. The two groups were comparable at entry. Clinical remission was obtained in eight (80%) patients receiving ED and six (55%) patients receiving PD, p = 0.1. The treatment failed in three and two patients in the PD and ED groups, respectively. Another two patients were intolerant to the feed (PD). Reduction in the CDAI after treatment with ED (359 +/- 67 to 112 +/- 19) was similar to that seen with PD (303 +/- 27 to 97 +/- 11). Similar changes in the CRP were also observed (16 +/- 5 to 4 +/- 1.6) and (62 +/- 20 to 9 +/- 6), respectively. Overall, enteral feeding was successful in 14 patients (63%).

CONCLUSIONS

Enteral nutrition is effective in treatment of active Crohn's disease. Differences in nitrogen sources of enteral feeds are not relevant to their therapeutic efficacy, as polymeric and elemental diets are equally effective.

Colonoscopy and technetium-99m white cell scan in children with suspected inflammatory bowel disease

OBJECTIVES

To determine the utility of the technetium-labeled autologous white cell scintigraphy (Tc-WCS) for detecting intestinal inflammation in children with suspected inflammatory bowel disease (IBD). Tc-WCS was compared with colonoscopy and histologic examination.

STUDY DESIGN

Forty-eight children (26 boys; median age, 10 years; range, 2-17 years) with symptoms and signs suggesting IBD had colonoscopy with exploration of terminal ileum and mucosal biopsies. The scans were judged to be abnormal if activity was seen in the gut within the first hour.

RESULTS

Twenty-one patients had a diagnosis of IBD (Crohn's disease, 13; ulcerative colitis, 5; indeterminate colitis, 3); results of scintigraphy were positive in 16 and negative in 5 (sensitivity, 76.2%); the latter had a moderate degree of intestinal inflammation. In 27 patients, IBD was ruled out. Results of scintigraphy were negative in children with non-specific colitis and in those with lymphoid hyperplasia of the terminal ileum, whereas results were positive in 6 of 12 patients with spondyloarthropathy. In children with IBD, there was a significant correlation between results of scintigraphy and endoscopy for the intensity of inflammation (r = 0.70); however, there was a poor correlation regarding the number of involved segments (r = 0.30) because in 16 patients, endoscopy revealed additional diseased segments as compared with scintigraphy.

CONCLUSIONS

A positive Tc-WCS result indicates the presence of an inflammatory process of the gut, whereas a negative test result does not rule out intestinal inflammation, especially when the latter is of moderate degree. Colonoscopy and biopsy are the investigations of choice to establish the diagnosis of IBD and are superior to Tc-WCS in assessing topographic extension of IBD.

Experimental colitis induced by trinitrobenzenesulfonic acid: an ultrastructural and histochemical study

Inflammatory bowel disease (IBD) of humans is a chronic and devastating disease of unknown etiology. Models of acute colitis in animals have been achieved by intrarectal administration of agents such as 2,4,6-trinitrobenzenesulfonic acid (TNBS) into rat colon. This agent induces focal inflammation and alterations in the colon with features similar to those found in chronic inflammatory diseases in humans. The aim of this study was to assess the effect of TNBS administration on histological and ultrastructural features of the rat colon, especially in areas not affected by transmural inflammation. Also in areas without transmural inflammation, we observed a significant increase in crypt diameter and in the number and area of the goblet cells, as well as alterations in the contents of mucin in goblet cells. We conclude that TNBS treatment in rats led to severe changes in normal architecture of the colon and also in damaged areas where no direct inflammation was produced.

Pediatric inflammatory bowel disease: assessment with scintigraphy with 99mTc white blood cells

PURPOSE

To evaluate the sensitivity and specificity of scintigraphy with technetium 99m white blood cells (WBC) for detection of colonic inflammation in children with and children without inflammatory bowel disease (IBD).

MATERIALS AND METHODS

In 215 patients, uptake of 99mTc WBC in 3,440 bowel segments was graded. In 137 of the 215 patients, the 99mTc WBC scans were interpreted blindly and findings compared with results at colonoscopy and endoscopic biopsy. Planar, single photon emission computed tomographic, and maximum-activity-projection images were reviewed together. In 78 children without recent endoscopic biopsy results, 99mTc WBC scan findings were compared with laboratory values, the gastroenterologist's initial clinical assessment, and findings at long-term clinical follow-up.

RESULTS

In 128 of 137 children with recent biopsies, findings at histologic examination and on 99mTc WBC scans were correlated. There were seven false-negative and two false-positive studies. Sensitivity was 90%, specificity 97%, positive predictive value 97%, negative predictive value 93%, prevalence of disease 53%, and overall accuracy 93%. In 75 of 78 (96%) children without recent biopsies, 99mTc WBC scan findings were consistent with the laboratory values, gastroenterologist's clinical assessment, and long-term clinical follow-up findings.

CONCLUSION

Scintigraphy with 99mTc WBC is a useful noninvasive diagnostic test to determine the extent and distribution of inflammation in children with IBD.

A prospective randomized trial comparing the use of omeprazole-based dual and triple therapy for eradication of Helicobacter pylori

BACKGROUND

Controversy surrounds the optimal composition, dosage, and duration of therapies for eradication of Helicobacter pylori. We prospectively compared omeprazole-based dual and triple therapies in the eradication of H. pylori in a randomized manner.

METHODS

Between June 1995 and March 1997, 1000 consecutive patients with acid-peptic disease associated with H. pylori infection (duodenal ulcer, 388 patients, gastric ulcer, 179 patients; duodenitis, 173 patients; gastritis, 260 patients) were prospectively recruited. They were randomized to either a 2-wk (OA) course of omeprazole 20 mg and amoxicillin 1 g, both given twice daily, or treatment for 1 wk (OCM) with omeprazole 20 mg once daily, clarithromycin 500 mg twice daily, and metronidazole 400 mg twice daily.

RESULTS

The age of these 1000 patients ranged from 16 to 90 yr, with a mean of 54.9 yr. Side effects occurred in 29.6% (95% confidence interval [CI] 25.6-33.8%) and 10.6% (95% CI 8.0-13.6%) of patients taking OCM and OA, respectively (p < 0.0001). Apart from taste disturbance, however, there were no significant differences in the incidences of side effects between the two groups. One patient in the OA group and four patients of the OCM group could not tolerate the medications, and therefore did not complete treatment (p = 0.37). Seven and 13 patients in the OA and OCM groups, respectively, refused a second endoscopy (p = 0.25). The remaining 975 patients underwent a second endoscopy. Positive endoscopic findings were significantly more common in the OA group (51/492; 10.4%; 95% CI 7.8-13.4%) than in the OCM group (25/483; 5.2%; 95% CI 3.4-7.5%) in the per-protocol (PP) analysis (p = 0.004). On intent-to-treat (ITT) analysis, the overall eradication rates in the OA and OCM groups were 73.6% (95% CI 69.5-77.4%) and 92% (95% CI 89.3-94.2%), respectively (p < 0.0001). On PP analysis, the corresponding rates were 74.8% (95% CI 70.7-78.6%) and 95.2% (95% CI 92.9-97.0%), respectively (p < 0.0001).

CONCLUSIONS

A course of omeprazole, clarithromycin, and metronidazole for 1 wk is a safe, well-tolerated, efficacious, and cost-effective treatment for H. pylori infection.

Effects of Helicobacter pylori on gastritis, pentagastrin-stimulated gastric acid secretion, and meal-stimulated plasma gastrin release in the absence of peptic ulcer disease

OBJECTIVE

There is strong evidence accumulating that chronic infection with Helicobacter pylori (H. pylori) interferes with inhibitory pathways of the regulation of acid secretion. The increase in maximum acid output (MAO), and the increase in the sensitivity of the parietal cell to gastrin commonly observed in patients suffering from duodenal ulcer disease (DU), however, remains largely unexplained. Insufficient evidence is available concerning how these parameters are influenced by H. pylori infection in patients not suffering from peptic ulcer disease (PUD) and how they are related to H. pylori-induced gastritis. The aim of this study was to compare basal gastric acid secretion (BAO), MAO, and the sensitivity of the parietal cell to gastrin in H. pylori-positive and H. pylori-negative patients not suffering from PUD, and to study the relationship with their individual postprandial gastrin release and the degree of gastric antral and corpus gastritis.

METHODS

H. pylori status was assessed by CLO test and histology (two biopsies each from the antrum and the corpus) in 14 H. pylori-positive and 16 H. pylori-negative nonulcer patients of comparable age, weight and gender. Gastritis score was assessed by a pathologist, who was unaware of the acid secretory data. Following determination of BAO, the relation of pentagastrin and gastric acid secretion was established with a cumulative pentagastrin dose response curve for the dose range 0.03-6.0 microg/kg(-1) h(-1) and MAO (Vmax) and pentagastrin sensitivity (ED50) were determined. Basal and postprandial gastrin release was measured by radioimmunoassay.

RESULTS

There was a significant higher gastritis score in the H. pylori-positive compared with the H. pylori-negative subjects. The dose response curves of the pentagastrin stimulated gastric acid secretion were not different between H. pylori-positive and H. pylori-negative groups. No correlation was seen between the gastritis score, basal acid output (BAO) peak acid output (PAO), maximum acid output (MAO), ED50 values and the plasma gastrin values. There was, however, a considerable larger variation of the PAO and MAO data of the H. pylori-infected subjects and >50% of the respective data was above or below the relatively low range of the respective values of the noninfected subjects.

CONCLUSIONS

H. pylori-induced gastritis does not regularly enhance maximum acid output in nonulcer patients, nor does it modify the sensitivity of the parietal cell to gastrin. H. pylori infection is thus unlikely to be directly responsible for an increase of these parameters in DU disease. Our data support, however, the concept that chronic H. pylori infection can either enhance or attenuate maximum acid secretory capacity in certain subgroups of patients.

Triple versus dual therapy for eradicating Helicobacter pylori and preventing ulcer recurrence: a randomized, double-blind, multicenter study of lansoprazole, clarithromycin, and/or amoxicillin in different dosing regimens

OBJECTIVE

The efficacy and safety of dual and triple therapies with a proton pump inhibitor and antibiotic(s) for therapy of Helicobacter pylori-associated duodenal ulcer disease have been compared using results from independent studies using different methods and regimens, making interpretation difficult. In a large, double-blind, multicenter study conducted in the United States, we compared a triple therapy regimen with four dual therapy and one monotherapy regimens in the eradication of H. pylori and the prevention of ulcer recurrence.

METHODS

Patients with active duodenal ulcer disease or history of duodenal ulcer disease within the past year and H. pylori infection were randomized to receive one of six 14-day treatment regimens: lansoprazole 30 mg, clarithromycin 500 mg, and amoxicillin 1 gm b.i.d.; lansoprazole 30 mg b.id. and either clarithromycin 500 mg b.i.d. or t.i.d.; lansoprazole 30 mg b.i.d. or t.i.d. with amoxicillin 1 gm t.i.d.; or lansoprazole 30 mg t.i.d. alone. No additional acid suppression therapy followed eradication therapy. Primary efficacy endpoints were eradication of H. pylori and ulcer recurrence.

RESULTS

Of 396 patients enrolled in the study, 352 met the entry criteria for duodenal ulcer status and H. pylori positivity. At 4-6 wk after the end of therapy, H. pylori was eradicated from 94% (44 of 47) of patients receiving lansoprazole, clarithromycin, and amoxicillin triple therapy, 77% (39 of 51) of those receiving lansoprazole t.i.d./amoxicillin t.i.d., 75% (36 of 48) of those receiving lansoprazole b.i.d./clarithromycin t.i.d., 57% (28 of 49) of those receiving lansoprazole b.i.d./clarithromycin b.i.d., 53% (26 of 49) of those receiving lansoprazole b.i.d./amoxicillin t.i.d., and 2% (1 of 53) of those receiving lansoprazole monotherapy (p < or = 0.05, triple therapy vs each dual therapy and each dual therapy vs monotherapy). Of those patients who were documented as free of ulcer at 4-6 wk after treatment, ulcers recurred within 6 months in 7% of patients receiving triple therapy, as compared with 13-23% of patients receiving dual therapy, and 69% of patients receiving lansoprazole monotherapy. Patients who were H. pylori negative at 4-6 wk after treatment were less likely to have an ulcer recurrence than were patients who were H. pylori positive (11% [10 of 95] vs 47% [20 of 43], respectively, across treatment groups). For triple therapy and dual therapy, a similar proportion of patients reported a drug-related adverse event (23% vs 17-33%, respectively).

CONCLUSIONS

In patients with active or a recent history of duodenal ulcer, a 14-day course of lansoprazole-based triple therapy without additional acid suppression therapy is highly effective in the eradication of H. pylori and in preventing ulcer recurrence. Among the dual therapies, higher eradication rates occurred when lansoprazole (with amoxicillin) or clarithromycin (with lansoprazole) was administered t.i.d. vs b.i.d., but the rates were still significantly lower than with lansoprazole triple therapy with all three drugs administered b.i.d.

Crohn's disease: new imaging techniques

This chapter reviews the current state of imaging in Crohn's disease. Imaging plays an important role in the diagnosis and management of Crohn's disease. Imaging is complementary to the clinical assessment of the patient and other investigations including endoscopy. The choice of imaging modality depends on the clinical circumstances and local availability of resources and skills. Close co-operation between clinicians and radiologists is important. Barium radiology remains important. Magnetic resonance imaging (MRI) and ultrasound (US) should get special consideration because of the lack of ionizing radiation. MRI is particularly good at demonstrating the perianal complication of Crohn's disease. Computer tomography (CT) and US can be used for image-guided drainage of abscesses.

The technetium white cell scan as an initial imaging investigation for evaluating suspected childhood inflammatory bowel disease

BACKGROUND

The technetium white cell scan (WCS) may be a useful investigation for patients with inflammatory bowel disease (IBD). In a retrospective study we assessed the use of the WCS as an initial imaging investigation in evaluating children with suspected IBD.

METHODS

Over a 3-year period, 60 WCS were performed on 55 patients (25 boys, median age 12.1 years, age range 1.5-18 years) with known or suspected IBD. There were two clinical groups: those with previously diagnosed IBD (histologically and radiologically) and in clinical relapse (13 patients), and newly presenting patients with suspected IBD (42 patients).

RESULTS

Eighteen scans were performed on the 13 patients presenting with relapse. Seventeen were positive and one patient, subsequently shown to have an inactive stricture, had a negative scan. Seven of the 42 newly presenting patients had abnormal scans, confirmed to be due to IBD by a combination of histology and barium examinations. Of the remaining 35 scans, three were abnormal and 32 were normal. None of these patients were subsequently proven to have IBD. These results show that in detecting active IBD, a positive WCS has a 100% sensitivity (24/24) and a 91% specificity (32/35) in the diagnosis of IBD.

CONCLUSIONS

Our results show that the WCS is very useful as an initial imaging investigation in evaluating patients with suspected IBD to select patients for further investigation.

Management of the first presentation of severe acute colitis

Prompt diagnosis and exclusion of infection requires a minimum of rigid sigmoidoscopy, rectal mucosal biopsy and stool culture. Admission to hospital is mandatory for patients with features of severe disease, or who are in their first attack of ulcerative colitis and have bloody diarrhoea, even if the criteria for severe disease are not met. Once admitted, the patient should be monitored by plain abdominal X-ray, full blood count, serum albumin and C reactive protein on alternate days; temperature and pulse rate should be recorded four times per day. Treatment should be instituted as soon as the diagnosis is made with an intravenous corticosteroid (hydrocortisone 100 mg intravenously, four times daily, or equivalent). Antibiotics may be included if infection cannot be confidently excluded. Free diet can be allowed but attention should be given to nutritional, fluid and electrolyte status with intravenous replacement if necessary. Any evidence of colonic dilatation occurring despite maximal therapy should be regarded as an absolute indication for colectomy. The patient should be kept fully informed from an early stage about the likely natural history of the condition and about the possible therapeutic options including surgery. Cyclosporin therapy should be reserved for patients who have a poor response to the first 3-4 days of corticosteroid therapy, particularly those with serum C reactive protein > 45 mg/l and who do not yet have absolute indications for colectomy. Most patients who have not convincingly responded within 10 days of starting full medical therapy should undergo colectomy, although partial responders who are afebrile may reasonably continue for up to 14 days before a final decision. Approximately 30-40% of patients with severe colitis will need colectomy within the first 6 months. With optimal management, mortality should be zero, but better medical therapies are urgently needed to reduce the colectomy rate.