Activation of signal transducer and activator of transcription (STAT) 1 in human chronic inflammatory bowel disease.

BACKGROUND: Increased expression of proinflammatory cytokines, including tumour necrosis factor alpha, interleukin 6, and interferon gamma, as well as activation of proinflammatory signalling molecules such as nuclear factor kappa B, is characteristic of inflammatory bowel disease (IBD). AIMS: To investigate expression and activation of signal transducer and activator of transcription (STAT) 1 in patients with IBD. PATIENTS: Patients with active IBD (n=42), disease specificity controls (n=8), and normal controls (n=12) were investigated. METHODS: Expression and activation of STAT1 were assessed by western blotting and electrophoretic mobility shift assays in extracts of endoscopic colonic biopsies. Cellular localisation was determined by immunohistochemistry. RESULTS: Western blots and immunohistochemical staining revealed an increase in STAT1 expression and activation in mucosal samples from ulcerative colitis and to a lesser extend in Crohn's disease patients. High levels of suppressor of cytokine signalling (SOCS)-3 expression, an inhibitor of STAT activation, were observed in Crohn's disease patients and normal controls in western blot experiments whereas no differences were observed for SOCS-1 expression. Phosphorylated (p) STAT1 was mainly detected in monocytic cells and neutrophils in the inflamed mucosa. Induction of remission by systemic glucocorticoids led to a decrease in levels of pSTAT1. In vitro studies indicated a direct effect of steroid treatment on STAT1 activation. CONCLUSIONS: Expression and activation of STAT1 are predominantly heightened in ulcerative colitis and may therefore play an important role in the pathophysiology of colonic inflammation.

Low dose balsalazide (1.5 g twice daily) and mesalazine (0.5 g three times daily) maintained remission of ulcerative colitis but high dose balsalazide (3.0 g twice daily) was superior in preventing relapses.

BACKGROUND: Balsalazide is a new 5-aminosalicylic acid (5-ASA) containing prodrug. Its efficacy in comparison with standard mesalazine therapy and the optimum dose for maintaining remission of ulcerative colitis are still unclear. AIMS: To compare the relapse preventing effect and safety profile of two doses of balsalazide and a standard dose of Eudragit coated mesalazine. METHODS: A total of 133 patients with ulcerative colitis in remission were recruited to participate in a double blind, multicentre, randomised trial: 49 patients received balsalazide 1.5 g twice daily, 40 received balsalazide 3.0 g twice daily, and 44 received mesalazine 0.5 g three times daily. Efficacy assessments were clinical activity index (CAI) and endoscopic score according to Rachmilewitz, and a histological score. In addition, laboratory tests were performed and urinary excretion of 5-ASA and its metabolite N-Ac-5-ASA was analysed. The study lasted for 26 weeks. RESULTS: Balsalazide 3.0 g twice daily resulted in a significantly higher clinical remission rate (77.5%) than balsalazide 1.5 g twice daily (43.8%) and mesalazine 0.5 g three times daily (56.8%) (p=0.006). The respective times to relapse were 161 days, 131 days (p=0.003), and 144 days (NS). Accordingly, pairwise contrasts of the final endoscopic score demonstrated a significant difference (p=0.005) between the two balsalazide treatment groups while differences between either of these two groups and mesalazine were not statistically significant. Patients treated with balsalazide excreted less 5-ASA and N-Ac-5-ASA than patients receiving mesalazine but these differences were not statistically significant. Discontinuation of the trial because of adverse effects occurred in nine patients: three in the balsalazide 1.5 g twice daily group, two in the balsalazide 3.0 g twice daily group, and four in the mesalazine 0.5 g three times daily group. No clinically important new drug safety related findings were identified in this study. CONCLUSIONS: High dose balsalazide (3.0 g twice daily) was superior in maintaining remission in patients with ulcerative colitis compared with a low dose (1.5 g twice daily) or a standard dose of mesalazine (0.5 g three times daily). All three treatments were safe and well tolerated.

Switch from systemic steroids to budesonide in steroid dependent patients with inactive Crohn's disease.

BACKGROUND: Steroid dependent patients with Crohn's disease are at high risk of developing glucocorticosteroid induced side effects. AIMS: We evaluated the possibility of switching from systemic steroids to budesonide (Entocort) in prednisolone/prednisone dependent patients with inactive Crohn's disease affecting the ileum and/or ascending colon. PATIENTS: Steroid dependent patients with a Crohn's disease activity index 200 and an increase of 60 points from baseline or withdrawal due to disease deterioration. RESULTS: After one and 13 weeks without prednisolone, relapse rates were 17% and 32%, respectively, in the budesonide group, and 41% and 65% in the placebo group (95% confidence intervals for the difference in percentages -41%, -8% and -51%, -16%; p=0.004 and p<0.001, respectively). The number of glucocorticosteroid side effects was reduced by 50% by switching from prednisolone and was similar in the budesonide and placebo groups. Basal plasma cortisol increased in both groups. CONCLUSIONS: The majority of patients with steroid dependent ileocaecal Crohn's disease may be switched to budesonide controlled ileal release capsules 6 mg without relapse, resulting in a sharp decrease in glucocorticosteroid side effects similar to placebo, and with an increase in plasma cortisol levels.

Mycophenolate mofetil: lack of efficacy in chronic active inflammatory bowel disease.

BACKGROUND: Mycophenolate mofetil (MMF) is a new immunosuppressant with pharmacodynamic properties comparable to azathioprine. Recent reports found MMF to be effective in inflammatory bowel disease (IBD). METHODS: An open-label prospective and uncontrolled multicentre 6 month trial of MMF in combination with steroids was conducted in 24 chronic active IBD patients. A daily steroid demand of >/= 10 mg prednisone in the preceding 2 months and a Crohn's disease activity index (CDAI) > 150, or moderate to severe activity according to Truelove, served as criteria for chronic activity. The treatment consisted of a steroid pulse and tapering protocol in combination with MMF 2 g/day. A prednisone dose of 5 mg/day was maintained during months 4-6. The primary end-point was induction and maintenance of remission. RESULTS: Only 10 of 24 patients had achieved remission after 3 months. All but one Crohn's disease patient had relapsed by the end of the study at 6 months. Depression and migraine necessitated drug withdrawal in two patients. CONCLUSION: In conclusion, MMF 2 g/day was unable to induce and maintain remission for a period of 6 months in 23 of 24 chronic active IBD patients. Further controlled investigations are required in view of recent conflicting reports.

Lack of clinical efficacy of additional factor XIII treatment in patients with steroid refractory colitis. The Factor XIII Study Group.

Patients with active ulcerative colitis have decreased levels of factor XIII (FXIII) activity, which is important for woundhealing. Recent uncontrolled studies claimed a beneficial effect of Factor XIII on clinical symptoms of ulcerative colitis, in particular intestinal bleeding. The objective of this trial was to evaluate the benefits of additional FXIII treatment in steroid-refractory patients with ulcerative colitis in a prospective, double blind, placebo-controlled study. A total of 28 patients were enrolled between October 1994 and January 1997. Primary objective of this study was the time until cessation of visible intestinal bleeding with 14 days after the start of treatment. Patients were treated for ten days either by i.v. application of FXIII concentrate or by placebo. The analysis of the primary efficacy criterion, cessation of intestinal bleeding, by a planned interim analysis showed no significant differences between the treatment groups (p = 0.8). This resulted in the termination of the study. The same applied to the CAI score. No patient in both treatment groups reached remission according to the colo-/-sigmoidoscopy score. Due to the high number of patients (16 of 28) who had to be excluded from the per-protocol analysis (e.g. changes to the concomitant medication) only the intention-to-treat population was analyzed. Overall the study showed no beneficial effect of additional FXIII treatment on active steroid-refractory ulcerative colitis. These results do not confirm previous open label studies which had reported a significant improvement of clinical symptoms.

Tumour necrosis factor alpha and interleukin 1beta in relapse of Crohn's disease.

BACKGROUND: Concentrations of proinflammatory cytokines are increased in the intestinal mucosa of patients with active Crohn's disease. Experimental immunotherapeutic interventions with anticytokine agents in refractory Crohn's disease show that tumour necrosis factor alpha (TNF alpha) may be an important mediator of inflammation. We investigated the relation between production of TNF alpha and interleukin 1beta by mononuclear cells of the colonic lamina propria in patients with remitting Crohn's disease and the risk of relapse. METHODS: We followed up 137 patients with Crohn's disease in steroid-induced remission for 1 year. Secretion of proinflammatory cytokines (tumour necrosis factor alpha [TNF alpha] and interleukin 1beta) was assessed after short-term culture of human lamina propria mononuclear cells. FINDINGS: Increased secretion of TNF alpha and interleukin 1beta were predictive for acute relapses within the next year. Site and extent of disease, baseline demographics, and serum acute-phase proteins had little predictive value. INTERPRETATION: TNF alpha is important as a target molecule for immune interventions in Crohn's disease. The capacity to produce TNF alpha or interleukin 1beta may identify patients who would benefit from anti-inflammatory remission maintenance.

Renal tubular dysfunction in patients with inflammatory bowel disease treated with aminosalicylate.

BACKGROUND: An increasing number of case reports indicate potential nephrotoxicity of 5-aminosalicylic acid (5-ASA), which shares similarities with the chemical structures of both phenacetin and acetylsalicylic acid. AIM: In a point prevalence study the occurrence of sensitive indices indicative of early kidney malfunction was assessed in outpatients with inflammatory bowel disease. METHODS: Routine indices of kidney function (creatinine clearance, urinary protein content, pH, electrolytes, and microscopy) were investigated in 223 patients with inflammatory bowel disease as well as sensitive markers of glomerular or tubular dysfunction (microproteinuria by SDS polyacrylamide gel electrophoresis (SDS-PAGE), urinary concentrations of N-acetyl-beta-D-glucosaminidase, alpha 1-microglobulin, gamma-glutamyltransferase (GGT), alkaline phosphatase (AP), and albumin). Histories of exposure to 5-ASA were assessed by questionnaire. RESULTS: Patients receiving high amounts of 5-ASA, both actual as well as on a lifetime basis, showed an increased prevalence of tubular proteinuria by SDS-PAGE. Raised values for urinary AP and GGT indicate proximal tubular epithelial cells as the source. All other kidney function tests were normal. Analysis of covariates indicated strong associations between disease activity and size of 5-ASA doses as well as alterations in kidney tubular function. CONCLUSION: The possibility exists that high doses of 5-ASA may be associated with proximal tubular proteinuria. This point prevalence study cannot dissect the possible impact of chronic inflammation from high dose 5-ASA treatment and further prospective studies are warranted.

5-Aminosalicylic acid-associated renal tubular acidosis with decreased renal function in Crohn's disease.

The use of 5-aminosalicylic acid (5-ASA, mesalazine) in Crohn's disease is usually well tolerated. Nevertheless, the occasional occurrence of nephrotoxic side effects has been described in several case reports. We present the case of a 34-year-old female in whom chronic use of 5-ASA may have caused renal damage which manifested with tubular acidosis, severe weight loss, shortness of breath and fatigue. For 17 years the patient has suffered from Crohn's disease. She received sulfasalazine (3 g/day) for 12 years and was treated with resin-coated mesalazine (3 g/day) for the last 72 months. Onset of weight loss of 10 kg over a 6-month period, accompanied by progressive shortness of breath and fatigue, lead to a diagnosis of metabolic acidosis and renal bicarbonate loss due to damage to the tubular epithelium. Kidney biopsy demonstrated acute interstitial nephritis which may be related to 5-ASA.

Peripheral lactate and oxygen metabolism in man: the influence of oral glucose loading.

We investigated the influence of oral glucose loading (100 g) on glucose, lactate, and oxygen metabolism by deep (mainly muscle) and superficial (mainly skin and adipose tissue) forearm tissues. In normal men aged 19 to 32 years (mean +/- SE, 24 +/- 1), basal arterialized venous-deep venous (A-DV) and arterialized venous-superficial venous (A-SV) plasma glucose concentration differences were 4.1 +/- 1.0 (P less than 0.001) and 4.7 +/- 1.0 (P less than 0.005) mg/dL, respectively, but increased markedly following glucose loading. During the first, second, and third hours after glucose ingestion, A-DV differences were 54 +/- 6,43 +/- 3, and 20 +/- 4 mg/dL, respectively, while the corresponding A-SV differences were 39 +/- 4, 17 +/- 2, and 8 +/- 2 mg/dL, respectively. Forearm glucose uptake by deep (FGU-D) and superficial (FGU-S) tissues basally was 0.057 +/- 0.010 and 0.012 +/- 0.002 mg/100 mL forearm/min respectively. From 15 to 180 minutes after glucose loading, mean FGU-D and FGU-S rose to 0.524 +/- 0.083 and 0.056 +/- 0.006 mg/100 mL forearm/min, respectively. Basal A, SV, and DV lactate concentrations were 0.55 +/- 0.04, 0.78 +/- 0.03, and 0.57 +/- 0.04 mmol/L, respectively (A-SV, P less than 0.001; SV-DV, P less than 0.001; A-DV, NS). Lactate production by superficial tissues (0.079 +/- 0.015 mumol/100 mL forearm/min) accounted for 62% of concurrent FGU-S.(ABSTRACT TRUNCATED AT 250 WORDS)

Basal glucose homeostasis with and without fixed concentrations of glucagon and insulin.

The aim of this study was to investigate the extent to which the basal steady state could be maintained with fixed concentrations of glucagon and insulin. To this end, arterial plasma glucose concentrations and peripheral glucose uptake (using the forearm technique) were compared in healthy men (age 19 to 23 years) in the normal postabsorptive state and after suppression of endogenous pancreatic secretion. Two groups (A and B), each consisting of four men, were studied. In group A, the study comprised a control period (I) of 40 minutes followed by a test period (II) of 180 minutes during which normal pancreatic secretion was maintained throughout. In group B, the study comprised a control period (I) of 40 minutes, a stabilization period (II) of 120 minutes, and a test period (III) of 120 minutes. After the control period with normal pancreatic secretion, a new steady state with fixed hormone concentrations was established during the first 90 minutes of period II using simultaneous infusions of somatostatin (250 micrograms/h), insulin (0.15 mU/kg/min) and glucagon, the latter being adjusted to maintain a stable arterial glucose level similar to the preceding control concentration. Thereafter, without further adjustment of the glucagon infusion rate, observations were continued during period III to assess the maintenance of the steady state. In group A, the range of variation in arterial glucose concentrations during periods I and II was 4.0 +/- 0.9 and 6.5 +/- 1.3 mg/dL, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of graded hyperglycemia with and without physiological hyperinsulinemia on forearm glucose uptake and other metabolic responses in man.

We studied the influence of hyperglycemia on glucose homeostasis in man by determining the effect of graded hyperglycemia on peripheral glucose uptake and systemic metabolism in the presence of basal and increased serum insulin concentrations in 10 normal men. This was achieved by the simultaneous application of forearm and clamp techniques (euglycemic and hyperglycemic) during the combined iv infusion of somatostatin, glucagon, and insulin. While mean (+/- SE) basal serum insulin levels (14 +/- 2 microU/ml) were maintained, the elevation of fasting arterial glucose concentrations (90 +/- 1 mg/dl) to 146 +/- 1 and 202 +/- 1 mg/dl (each for 120 min) increased forearm glucose uptake (FGU) only modestly from 0.06 +/- 0.01 to 0.15 +/- 0.02 and then to 0.24 +/- 0.03 mg/100 ml forearm X min, respectively. During physiological hyperinsulinemia (47 +/- 3 microU/ml), the influence of similar graded hyperglycemia on FGU was considerably enhanced. At plasma glucose concentrations of 90 +/- 1, 139 +/- 1, and 206 +/- 1 mg/dl, FGU rose to 0.33 +/- 0.05, 0.59 +/- 0.07, and 0.83 +/- 0.12 mg/100 ml forearm X min, respectively. The glucose infusion rate required to maintain the glucose clamp with basal insulin levels was 1.08 +/- 0.20 and 2.67 +/- 0.39 mg/kg X min at glucose concentrations of 146 +/- 1 and 202 +/- 1 mg/dl, respectively. During physiological hyperinsulinemia, however, the glucose infusion rate required was 4.15 +/- 0.39, 9.45 +/- 1.05, and 12.70 +/- 0.81 mg/kg X min at glucose levels of 90 +/- 1, 139 +/- 1, and 206 +/- 1 mg/dl, respectively. Lactate concentrations rose significantly during hyperglycemia, but the rise in the presence of increased insulin concentrations (from 0.72 +/- 0.06 to 1.31 +/- 0.11 mmol/liter; P less than 0.001) considerably exceeded the increment (from 0.74 +/- 0.05 to 0.92 +/- 0.03 mmol/liter) with basal insulin levels. While both FFA and glycerol concentrations were immediately reduced by euglycemic hyperinsulinemia, the fall in FFA during hyperglycemia in the presence of basal insulin levels preceded the decrease in glycerol concentrations by 45 min. Forearm oxygen consumption did not change throughout the study.(ABSTRACT TRUNCATED AT 400 WORDS)

Relationship among peripheral glucose uptake, oxygen consumption, and glucose turnover in postabsorptive man.

To assess the importance of glucose uptake by muscle in determining total glucose utilization in the basal state, forearm glucose uptake (FGU), reflecting mainly skeletal muscle metabolism, and glucose turnover using [3-3H]glucose were studied simultaneously in 17 postabsorptive normal men. Mean +/- SE glucose disappearance was 2.36 +/- 0.14 mg/kg X min, amounting to 170 +/- 9 mg/min, while FGU was 0.049 +/- 0.009 mg/100 ml forearm X min. When the latter was calculated in terms of skeletal muscle in the body as a whole, muscle glucose utilization was found to be 24.7 +/- 4.5 mg/min, comprising only 13.5 +/- 1.9% of the total glucose disappearance. Forearm oxygen consumption was 6.6 +/- 0.5 mumol/100 ml forearm X min, of which only 26 +/- 5% could be accounted for by concurrent glucose uptake. These results suggest that in the basal state, glucose uptake by skeletal muscle accounts for 1) only a small percentage of total glucose disappearance and 2) only a minor proportion of peripheral oxygen consumption, which may be more dependent on lipid oxidation.