Inhibition of coagulation by a phosphorothioate oligonucleotide

In the development of antisense therapeutics, there have been a number of hybridization-independent effects characterized for phosphorothioate oligodeoxynucleotides. One such effect is the transient prolongation of clotting times following intravenous infusion of high doses. In this study, inhibition of clotting times was characterized by determining the time course of both APTT and plasma oligonucleotide following intravenous infusion of ISIS 2302 in cynomolgus monkeys. Prolongation of APTT was also achieved by addition of ISIS 2302 to citrated blood from untreated monkeys, allowing the investigation of the mechanism of inhibition in vitro. Results from this study clearly indicate that the intrinsic pathway (APTT) was more sensitive to inhibition than the extrinsic pathway (PT). The prolongation of APTT was also shown to be transient and closely correlated with plasma oligonucleotide concentrations. The extent of APTT prolongation can be controlled by minimizing peak plasma oligonucleotide concentrations through lowering the dose or prolonging infusion duration. Direct addition of ISIS 2302 to blood produced quantitatively similar inhibition of clotting times. This effect was similar for a number of different phosphorothioate oligodeoxynucleotides, but oligonucleotides containing phosphodiester linkages and 2'-propoxy linkages were much less inhibitory. Additional in vitro studies indicated that the mechanism of inhibition was independent of that of heparin and possibly involved selective inhibition of the intrinsic pathway as well as the common clotting pathway. Investigation of selective clotting factors indicated that there was no direct inhibition of the enzymatic activity of factor Xa, XIa, or thrombin using chromogenic substrates. However, ISIS 2302 did produce a concentration-dependent increase in clotting time when fibrinogen was used as the substrate for thrombin.

A pharmacokinetic evaluation of 14C-labeled afovirsen sodium in patients with genital warts

Afovirsen sodium is a 20-mer phosphorothioate oligonucleotide designed to be complementary to the messenger ribonucleic acid sequence for the translation initiation codon of the E2 protein vital to replication of human papillomaviruses types 6 and 11. 14C-Labeled afovirsen was given as a single-dose intradermal injection in each of four warts of five patients to determine the time-dependent changes in concentration of intact afovirsen in genital warts and to determine the systemic absorption and elimination of radiolabeled compound. Intact afovirsen in genital warts was determined by high pressure liquid chromatography analysis of protease K digested extracts. Intact afovirsen was present in wart tissue for at least 72 hours at concentrations several times in excess of the estimated minimal inhibitory concentration of 1 mumol/L. Absorption of radiolabeled afovirsen from the injection site was rapid, with a peak plasma concentration achieved within 1 hour. Clearance of afovirsen was primarily attributable to slow metabolism, with about 30% of the radiolabel eliminated as 14C-CO2 in expired air over a 6-day period after dosing. Radioactivity eliminated in urine represented metabolites of afovirsen. From the clinical pharmacokinetic data presented here and from previously published pharmacokinetic data in rats, the disposition of afovirsen in humans appears to be relatively similar to that in rats. These data suggest that once or twice weekly dosing regimen in the clinic may be appropriate.

Is exocrine pancreatic insufficiency in adult coeliac disease a cause of persisting symptoms?

BACKGROUND

Patients with coeliac disease may have diarrhoea despite being on a gluten-free diet.

AIM

To assess whether exocrine pancreatic insufficiency causes persisting symptoms compared with controls, we determined whether pancreatic enzyme supplementation provided symptomatic benefit in coeliac patients with chronic diarrhoea.

METHODS

Patients (n = 259) were subdivided into four groups: (a) new coeliac disease (n = 57), (b) coeliac disease patients on a gluten-free diet without gastrointestinal symptoms (n = 86), (c) coeliac disease patients on a gluten-free diet with chronic diarrhoea (n = 66) and (d) patients with chronic diarrhoea without coeliac disease (n = 50). Stool frequency and weight, before and after treatment with pancreatic enzyme supplementation were recorded.

RESULTS

The prevalence of a low faecal elastase-1 within the groups was: group (A) six of 57 (11%), group (B) five of 86 (6%), group (C) 20 of 66 (30%) and group (D) two of 50 (4%). Low faecal elastase-1 was more frequent in coeliac disease patients with chronic diarrhoea vs. other subgroups of coeliac disease (P < or = 0.0001) and controls (P < or = 0.0003). In 18 of 20 stool frequency reduced following pancreatic enzyme supplementation from four per day to one (P < or = 0.001). No weight increase (P = 0.3) was observed.

CONCLUSIONS

Low faecal elastase is common in patients with coeliac disease and chronic diarrhoea, suggesting exocrine pancreatic insufficiency. In this group of patients, pancreatic enzyme supplementation may provide symptomatic benefit.

The occurrence of terminal ileal histological abnormalities in patients with coeliac disease

INTRODUCTION

Coeliac disease causes histological changes throughout the small bowel, but is often a proximal lesion. We wanted to assess whether terminal ileal histological abnormalities occurred more commonly in patients with coeliac disease and if specific assessment of intraepithelial lymphocytes increases the recognition of undiagnosed coeliac disease.

METHODS

Terminal ileal biopsies were prospectively examined over a 3-year period (April 2001-May 2004). Patients were included if they were found to have a synchronous duodenal biopsy that gave a new diagnosis of coeliac disease (n=20). Terminal ileal biopsies taken at colonoscopy during the same period were also examined from four groups of patients: coeliac disease established on a gluten-free diet but with persisting symptoms (n=25), inflammatory bowel disease (n=47), chronic diarrhoea (n=44) and polyp surveillance (n=47). All biopsies were graded according to the Marsh criteria and an intraepithelial lymphocytes count per 100 enterocytes was obtained.

RESULTS

There was only one patient from all five groups who had villous atrophy of the terminal ileal. This patient had a new diagnosis of coeliac disease. The mean intraepithelial lymphocytes count in the coeliac disease group was 23.7 intraepithelial lymphocytes/100 enterocytes. This was significantly higher than the control groups: coeliac disease on a gluten-free diet=17.5 (p<0.012), inflammatory bowel disease=12.3 (p<0.0001), diarrhoea=12.6 (p<0.0001) and polyp=13.7 (p<0.0002). Validating terminal ileal villous intraepithelial lymphocytes counts as a test for coeliac disease using an intraepithelial lymphocytes/100 enterocytes of >25 gives a sensitivity of 45% and a specificity of 97.8%.

CONCLUSION

Routinely quantifying terminal ileal intraepithelial lymphocytes may be of limited clinical value. However, subjective recognition of raised intraepithelial lymphocytes on a terminal ileal biopsy should alert the clinician to the possibility of coeliac disease.

Abnormal liver function tests in patients with Type 1 diabetes mellitus: prevalence, clinical correlations and underlying pathologies

AIMS

To determine the prevalence of elevated alanine transaminase (ALT) in a large cohort of patients with Type 1 diabetes and to examine the clinical correlations and causes. Methods Patients with Type 1 diabetes mellitus were prospectively recruited and ALT, glycated haemoglobin and lipid profile were measured. Patients with Type 2 diabetes mellitus were recruited as a comparison group.

PATIENTS

with abnormal ALT were investigated for underlying causes. Prevalence of abnormal ALT was analysed at three separate cut-offs and multivariable analysis used to identify independent risk factors.

RESULTS

Nine hundred and eleven with Type 1 diabetes and 963 with Type 2 diabetes were included. The prevalence of elevated ALT was dependent on the cut-off value: > 30 IU/l in males and > 19 IU/l in females, > 50 and > 63 IU/l was 34.5, 4.3 and 1.9%, respectively, in Type 1 diabetes and 51.4, 8.2 and 3.7%, respectively, in Type 2 diabetes. In Type 1 diabetes an elevated ALT was associated with worse glycaemic control, age > 55 years and elevated triglycerides. Investigation of these patients revealed a cause in 43.6% of patients, predominantly non-alcoholic fatty liver disease (NAFLD).

CONCLUSIONS

Elevated ALT is not uncommon in Type 1 diabetes and is associated with NAFLD-related risk factors. Patients with Type 1 diabetes and elevated ALT should be investigated as significant abnormalities may be found which are amenable to interventions.

Is formal training necessary for capsule endoscopy? The largest gastroenterology trainee study with controls

BACKGROUND

Little is known about the infrastructure to train gastroenterologists in capsule endoscopy. The level of capsule endoscopy exposure among trainees in the United Kingdom or Europe has also not been quantified.

AIMS AND METHODS

To assess the ability of 10 gastroenterology trainees with endoscopy experience to interpret 10 capsule endoscopy videos against five medical students, with an expert in capsule endoscopy as the gold standard. Parameters assessed included gastric emptying time, small bowel transit and the diagnosis made. A questionnaire survey assessed the level of capsule endoscopy exposure among United Kingdom trainees.

RESULTS

Trainees were better at determining the gastric emptying time (p=0.013) and more likely to record true positives compared to the students (p=0.037). They were also less likely to record false positives (p=0.005) and more likely to reach the correct diagnosis (p=0.001, OR 3.6, CI 1.8-7.4). Our survey found that, 65% of trainees had prior exposure to capsule endoscopy but only 13% had done capsule endoscopy reporting. Sixty seven percent felt capsule endoscopy should be incorporated into their training.

CONCLUSION

This study has shown that prior endoscopic experience enables trainees to interpret capsule endoscopy more accurately than medical students. However, there is a demand for focussed training which would enable trainees to reliably interpret pathology on capsule endoscopy.

Prodromal irritable bowel syndrome may be responsible for delays in diagnosis in patients presenting with unrecognized Crohn's disease and celiac disease, but not ulcerative colitis

INTRODUCTION

We aimed to determine the prevalence and duration of prodromal periods in patients with celiac disease and inflammatory bowel disease (Crohn's disease and ulcerative colitis). Furthermore, we explored to what extent vague abdominal symptoms consistent with both disorders were attributed to irritable bowel syndrome (IBS) and if the presence of prodromal IBS (P-IBS) had an impact on prodrome duration.

METHODS

In the study, 683 biopsy-proven patients (celiac n = 225, ulcerative colitis n = 228, Crohn's disease n = 230) completed a postal survey including an assessment of prodromal periods and IBS symptoms during both the prodrome and at present (achieved by completion of the ROME II criteria). Results were compared to age/sex-matched controls (n = 348).

RESULTS

Crohn's disease patients had the highest prevalence of prodromes (94%) in comparison to ulcerative colitis (48%) and celiac disease (44%). However, Crohn's disease patients have the lowest prevalence of P-IBS (29%) in comparison to ulcerative colitis (38%) and celiac disease (67%). Prodrome duration in patients with P-IBS Crohn's disease was 4 years in comparison to 2 years without (p = 0.018). Prodrome duration in P-IBS celiac disease was 10 years in comparison to 7 years without (p = 0.046). Prodrome duration in patients with ulcerative colitis was not affected by P-IBS (p ≥ 0.05). Age and sex were not confounding factors.

CONCLUSIONS

This is the first study to make direct comparisons of prodrome periods between celiac disease and IBD. Prodrome duration in celiac disease is significantly longer and more often characterized by P-IBS than IBD. In celiac disease and CD, P-IBS increases prodrome duration. This may represent a failure to understand the overlap between IBS and celiac disease/IBD.

Comparison of endoscopic ultrasound and computed tomography in the assessment of pancreatic cyst size using pathology as the gold standard

BACKGROUND/OBJECTIVES

Accurate assessment of whether a cyst is greater than 3 cm is an essential component when considering resection especially for mucinous lesions. The most accurate method of assessing cyst size is uncertain with many patients undergoing several complimentary imaging modalities. This study aimed to compare the accuracy of endoscopic ultrasound (EUS) with CT scanning in assessing pancreatic cyst size compared to histology.

METHODS

Patients referred for EUS of a pancreatic cystic lesion from April 2003 to August 2011. Patient age and gender, lesion size and site were recorded and compared using cyst size at histology compared to EUS and CT recorded within 3 months of surgery. Subgroup analysis was performed with respect to cyst site and proven mucinous lesions.

RESULTS

357 patients were included of which 70 (mean age 60.6 years, 24 males) had undergone surgical resection. The resected cysts were located 30/17/23 in the head/body/tail of the pancreas. Median size at histology was 32 mm compared to 35 mm at EUS (p = 0.47) and 35 mm at CT (p = 0.52). For mucinous lesions alone, median size at histology was 32 mm compared to 33 mm at EUS (p = 0.46) and 35 mm at CT (p = 0.39). EUS and CT had comparable sensitivity, specificity, negative predictive value, positive predictive value and accuracy for all cyst types and locations.

CONCLUSIONS

CT and EUS measurements are not significantly different to pathological size following resection of pancreatic cystic lesions. CT and EUS are interchangeable investigations for determining cyst size pre-operatively although EUS has the additional advantage of fluid sampling.

Serological testing for coeliac disease in Type 1 diabetes mellitus: is immunoglobulin A level measurement necessary?

AIMS

Immunoglobulin A (IgA) measurement is advocated when case finding for coeliac disease in patients with Type 1 diabetes mellitus. Currently, there is a paucity of contemporary studies assessing IgA deficiency in Type 1 diabetes. This study evaluates the prevalence of IgA deficiency in individuals with Type 1 diabetes, compared with patients with coeliac disease and control subjects. In addition, we evaluate whether routine IgA measurement is justifiable when case finding for coeliac disease in patients with Type 1 diabetes.

METHODS

All patients were assessed using IgA endomysial antibodies, IgA anti-tissue transglutaminase antibodies and total IgA levels. Altogether, 2434 individuals were tested: 1000 patients with Type 1 diabetes, 234 patients with coeliac disease and 1200 population control subjects. Definitive IgA deficiency was defined as total IgA levels < 0.07 g/l.

RESULTS

The prevalence of IgA deficiency was significantly more common in patients with Type 1 diabetes (0.9%, n = 9/1000; P = 0.036) and coeliac disease (1.29%, n = 3/234; P = 0.041) when compared with population control subjects (prevalence of 0.17%, 2/1200). No statistical difference between Type 1 diabetes and coeliac disease for IgA deficiency was identified (P = 0.87). Of patients in the group with Type 1 diabetes, 3.3% (33/1000) had coeliac disease, and of those only one patient had IgA deficiency leading to an antibody-negative presentation. Both IgA-deficient individuals within the population control subjects had normal duodenal biopsies and no relevant symptoms.

CONCLUSIONS

IgA deficiency is more common in Type 1 diabetes compared with population control subjects. Despite this, very few individuals with Type 1 diabetes and IgA deficiency appear to have villous atrophy on biopsy. These outcomes question the practice of routine IgA measurement when case finding for coeliac disease in patients with Type 1 diabetes.

Potential coeliac disease in Type 1 diabetes mellitus: does a positive antibody lead to increased complications?

BACKGROUND AND AIMS

Coeliac disease (CD) is more common in people with Type 1 diabetes and is associated with poorer glycaemic control, lipid profiles, nephropathy and retinopathy. Potential CD (positive serology but normal duodenal biopsy) is associated with neuropathy but patients with coexisting Type 1 diabetes were excluded. The aim was to determine whether potential CD is associated with increased microvascular complications in patients with Type 1 diabetes.

METHODS AND RESULTS

Four groups were recruited; 1) patients with Type 1 diabetes and potential CD, 2) patients with Type 1 diabetes and newly identified CD, 3) patients with Type 1 diabetes alone and 4) patients with CD alone. Glycaemic control, quality of life, lipid profile and microvascular complication rates were examined. As many as 76 individuals were included in the study: 22 in group 1, 14 in group 2, 24 in group 3 and 16 in group 4. There were no differences in age, gender, BMI and diabetes duration between the groups. Patients in group 1 had significantly lower total cholesterol compared to group 3 (p = 0.003) but higher than group 2 (p = 0.027). There were no significant differences in HbA1c, HDL cholesterol, cholesterol:HDL ratio, creatinine, quality of life scores or prevalence of neuropathy between individuals in group 1 and the other groups.

CONCLUSIONS

This is the first study to assess the effects of potential CD in patients with Type 1 diabetes. It appears that an enteropathy is required as well as antibody positivity in order to increase the risk of diabetes related complications. This pilot data requires further longitudinal validation.

Activation of the alternative pathway of complement by a phosphorothioate oligonucleotide: potential mechanism of action

Intravenous infusion of high doses of phosphorothioate oligonucleotides in monkeys has been associated with transient alterations in hematologic and hemodynamic parameters, which appear to be secondary to complement activation. ISIS 2302, a phosphorothioate oligonucleotide specific for human intracellular adhesion molecule-1, was used to further characterize complement activation in monkeys. Complement activation occurred selectively through the alternative pathway resulting in increased plasma concentrations of the complement split products Bb, C3a and C5a. Marked fluctuations in circulating neutrophil counts and reductions in cardiac output were closely associated with peak production of anaphylatoxins C3a and C5a. Changing both dose and infusion duration revealed that complement activation is related to plasma levels of oligonucleotide, and that there is a minimum threshold concentration of approximately 50 micrograms/ml of ISIS 2302 that is required to activate complement. Dose regimens in which plasma concentrations do not exceed this threshold do not result in complement activation. Further investigation reveals that plasma concentrations of a key regulatory component of the alternative pathway, Factor H, were also decreased after administration of ISIS 2302. Decreases in Factor H levels are suggestive of a possible mechanism of complement activation. Direct interaction between ISIS 2302 and Factor H was demonstrated in a competition assay, where increasing concentrations of ISIS 2302 eluted Factor H from a heparin-sepharose column. These data demonstrate a clear correlation between plasma oligonucleotide concentrations and complement activation. Interactions between ISIS 2302 and Factor H may lead to activation of the alternative complement pathway.

Occupational effects in patients with post-COVID-19 syndrome

BACKGROUND

It is well recognized that some individuals experience persistent symptoms following an initial SARS-CoV-2 infection. Symptoms affect physical, cognitive and mental well-being and can adversely impact activities of daily living, including the ability to work.

AIMS

To examine the impact of post-COVID-19 syndrome with respect to effects on quality of life and impact on work in a cohort of people referred to a 'Long COVID' service.

METHODS

All triaged patients (over 18 years with symptoms more than 12 weeks since the initial infection) completed a symptom assessment questionnaire. Occupation and working status (at work, at work struggling with symptoms and off work) were also recorded. Impact on function and quality of life was assessed using the EQ5D5L questionnaire.

RESULTS

A total of 214 patients (median age 51.0 years, 135 females) were seen from January to September 2021. Analysis of occupational status showed: 18% were working, 40% were working but struggling and 35% had stopped working due to symptoms. Those unable to work reported significantly more fatigue, a greater perception of the need for support and lower quality-of-life scores.

CONCLUSIONS

This study shows the extensive impact of post-COVID-19 syndrome on the ability to return to work. Specific return-to-work guidance is needed to support a large proportion of those struggling with the condition. The involvement of the Occupational Health team should form part of the multidisciplinary, collaborative approach to support rehabilitation and improve long-term outcomes for this condition.