Roger Hällgren

Regional rectal perfusion : a new in vivo approach to study rectal drug absorption in man

Background: In vivo permeability measurements of drugs in the colonic/rectal region in humans are difficult. A new instrument for the perfusion of a defined and closed segment in the colon/rectum was developed. The objective of this study was to evaluate its use for studying drug absorption mechanisms in the human rectum and to investigate the effect of transmucosal water absorption on drug permeability. Six healthy subjects participated at 2 separate occasions by using a modified system for segmental rectal perfusion. The system consisted of a multichannel tube with inflatable balloons and was endoscopically introduced into the rectum. The technique was considered acceptable by the following criteria; (a) high and reproducible recovery of PEG 4000, (b) stable residence time of the solution within the test segment, (c) flux of electrolytes that agrees with previous reports, (d) mass-balance absorption of antipyrine across the rectal barrier, (e) and good acceptability to the subjects. The permeability of antipyrine in the rectal region was increased by inducing net water absorption. D-glucose was not absorbed during any study periods. The present technique is valuable for studying drug absorption from the human rectum.

The jejunal secretion of histamine is increased in active Crohn's disease

Previous studies of mast-cell density and histamine content in biopsy specimens in patients with Crohns disease have yielded conflicting results. In this in vivo study we have measured the jejunal secretion rate of histamine in patients with Crohns disease (n = 15) of the terminal small bowel and in healthy controls (n = 24). The secretion studies were performed using a recently developed segmental jejunal perfusion system with a two-balloon, six-channel small tube. The histamine secretion rate was 152 +/- 29 (SEM) ng/cm small intestine per h in patients with Crohns disease, which meant a significant increase (p less than 0.01) compared with the secretion rate in controls (71 +/- 11 ng/cm per h). Moreover, the secretion of histamine was related to the disease activity. Patients with active disease (n = 8) (i.e., Crohns disease activity index greater than 150) had a mean histamine secretion rate of 193 +/- 47 ng/cm per h, while patients with inactive disease (Crohns disease activity index less than 150) had a secretion rate not significantly increased compared with controls (105 +/- 24 ng/cm per h). The present data indicate increased mast-cell involvement of the small intestine in active Crohns disease of the distal ileum. This finding might reflect the systemic nature of the disease process.

Dynamic role of hyaluronan (HYA) in connective tissue activation and inflammation

Gerdin B, Hällgren R (University Hospital, Uppsala, Sweden). Dynamic role of hyaluronan (HYA) in connective tissue activation and inflammation (Minisymposium: Hyaluronan). J Intern Med 1997; 242: 49–55.

Enhanced Local Production of Complement Components in the Small Intestines of Patients with Crohn's Disease

There is evidence that complement components may be formed locally in inflammatory lesions containing monocytes and macrophages. To investigate the role of complement in Crohns disease we measured jejunal-fluid concentrations of the complement components C4, C3, and factor B by perfusion of a closed segment of the jejunum in 22 patients with Crohns disease thought to be limited to the terminal ileum. The mean (+/- SEM) jejunal-fluid C4 concentration was 2.0 +/- 0.3 mg per liter, significantly higher than the mean level in 35 healthy controls (0.7 +/- 0.1 mg per liter; P less than 0.001). The mean C3 concentration was 1.0 +/- 0.1 mg per liter in the patients and 0.7 +/- 0.1 mg per liter in the controls (P less than 0.05). The factor B levels were similar in the two groups. Calculated rates of intestinal secretion of these components showed differences of the same magnitude. Leakage of protein from plasma was not increased. The jejunal-fluid:serum ratios of these complement proteins indicated that their appearance in the lumen of the jejunum was due to at least in part to local mucosal synthesis. The increased jejunal secretion of C4, but not C3 or factor B, paralleled the clinical activity of Crohns disease. Values were normal in first-degree relatives of the patients (n = 13), patients with celiac disease (n = 8), and patients with ulcerative colitis (n = 4). We conclude that increased secretion of complement by clinically unaffected jejunal tissue in patients with Crohns disease reflects the systemic nature of this disorder and may be due to the stimulated synthesis of complement by activated intestinal monocytes and macrophages.

Raised serum hyaluronate levels in scleroderma: an effect of growth factor induced activation of connective tissue cells?

The circulating levels of hyaluronate were determined in 36 patients with scleroderma and in 36 control subjects matched for age and sex. The mean serum hyaluronate concentration in patients with progressive systemic sclerosis (n = 25) was 131 +/- 67 (SD) microgram/l and significantly greater (p less than 0.001) than that of the controls (mean level 49 +/- 21 (SD) microgram/l). Hyaluronate levels in patients with localised scleroderma (n = 4) were 141 +/- 47 (SEM) microgram/l and in patients with scleroderma-associated overlap syndromes (n = 7) 202 +/- 54 (SEM) microgram/l. The increase in serum hyaluronate probably reflected an enhanced synthesis or outflow of hyaluronate from the connective tissue, or both; it could not be explained by affection of the liver, which is the catabolic site of hyaluronate. The hyaluronate values were not related to certain serological indicators of inflammatory activity or to the extent of the skin lesions or the severity of internal organ manifestations. A positive correlation was noted between circulating platelet counts and hyaluronate levels (p less than 0.001). Plasma beta-thromboglobulin was measured in 15 of the patients with systemic sclerosis and found to correlate positively with platelet counts. Raised levels of beta-thromboglobulin were associated with the highest hyaluronate values. Platelet-derived growth factor, which stimulates connective tissue cells and is stored in the alpha-granules of platelets together with beta-thromboglobulin, was shown to enhance hyaluronate synthesis in fibroblast cultures. The results suggest an involvement in scleroderma of connective tissue activating substances released from platelets.

Neutrophil and Eosinophil Involvement of the Small Bowel in Patients with Celiac Disease and Crohn's Disease: Studies on the Secretion Rate and Immunohistochemical Localization of Granulocyte Granule Constituents

PURPOSE The concentrations of myeloperoxidase (MPO), a neutrophil granule constituent, and eosinophil cationic protein (ECP), a specific eosinophil granule protein, were measured in jejunal perfusion fluid in an attempt to elucidate the neutrophil and eosinophil involvement of the small bowel in health and disease. PATIENTS AND METHODS The control group consisted of 14 males and two females. Ten patients (seven males and three females) with Crohns disease and seven patients (two males and five females) with celiac disease were also studied; in addition, one patient with relapsing giardiasis, one patient with giardiasis and complete absence of plasma cells in small intestinal lamina propria, and one patient with selective IgA deficiency and no IgA plasma cells in duodeno-jejunal lamina propria were evaluated. Segmental perfusion of the jejunum was performed according to a previously described method. MPO and ECP were measured by radioimmunoassays. RESULTS In healthy control subjects, the concentrations of both granule proteins were in a narrow range and much higher than would have been anticipated from passive leakage from circulating blood. In patients with celiac disease, the perfusion fluid concentrations of MPO and ECP were on average 3.5 and eight times, respectively, higher than the values seen in the controls. The jejunal segment perfused in patients with Crohns disease was endoscopically and histologically normal. The perfusion fluid concentrations of MPO and ECP were increased 3.5 and two times, respectively, compared with that in the control subjects. Both patient groups and the control group had similar perfusion fluid concentrations of albumin. Data on MPO and ECP expressed as jejunal secretion rates gave the same differences between patients and controls as just described for the jejunal fluid concentrations. Immunohistochemical studies of jejunal biopsy specimens from another group of patients with celiac disease demonstrated a prominent extracellular deposit of ECP in the lamina propria of the atrophic intestinal mucosa, whereas the release of neutrophil constituents (cathepsin G, MPO) was scarce. In Crohns disease, an extracellular degranulation of ECP and, to a lesser extent, of cathepsin G was observed in relation to ulcerations only. CONCLUSION Data obtained indicate that the local release of neutrophil and eosinophil granule components is enhanced in the jejunal tissue from patients with celiac sprue and Crohns disease. The prominent extracellular deposit of eosinophil granule constituents with cytotoxic properties at the site of inflammatory intestinal lesions in celiac sprue might reflect a pathophysiologic mechanism.(ABSTRACT TRUNCATED AT 400 WORDS)

Impaired glucose handling in active rheumatoid arthritis: relationship to peripheral insulin resistance.

Glucose metabolism was studied after an intravenous glucose loading in normal-weighted, previously untreated patients (n = 14) with active rheumatoid arthritis (RA). The patients displayed an enhanced insulin response and impaired glucose handling compared with healthy controls (P less than .001). The insulin sensitivity, measured as the glucose utilization rate during steady state of euglycemia (M) was significantly decreased (P less than .01) among the patients compared to the controls (5.5 +/- 1.9 mg/kg BW/min [mean +/- SD] and 7.2 +/- 1.2, respectively). The corresponding values for the metabolic clearance rate (MCR) were 5.8 +/- 0.6 mL/kg BW/min and 8.2 +/- 0.4, respectively (P less than .01). In the patient group the k value correlated with the peripheral insulin sensitivity (P less than .01), which, in turn, was inversely related to the acute phase reaction (P less than .05). During 1 week of potent anti-inflammatory treatment with corticosteroids (prednisolone 20 mg daily) the k value improved P less than .001), the insulin sensitivity tended to improve and the insulin response increased (P less than .001) after an intravenous glucose loading. Five patients who had a remission of their disease on sulphasalazine as antirheumatic therapy were reexamined. A normalization of the inflammatory activity as well as the glucose handling and insulin sensitivity was achieved. The data obtained indicate that impaired glucose handling in active RA is related to insulin resistance. The linkage between inflammatory indices and glucose metabolism might reflect a special consequence of inflammation, but the influence of nonspecific disease manifestations, ie, malnutrition, inactivity, and myopenia, has to be considered.

Human neutrophil lipocalin is a unique marker of neutrophil inflammation in ulcerative colitis and proctitis

Background and aim: Accumulation and infiltration by neutrophil granulocytes is a prominent feature in the local inflammatory process in ulcerative colitis (UC). The present study was performed to evaluate human neutrophil lipocalin (HNL) as a specific neutrophil marker in the inflamed lesions of the colon and rectum in patients with colitis and proctitis. Methods: The activity of intestinal neutrophils with respect to release of granule proteins was studied in 18 patients with UC (10 with colitis and eight with isolated proctitis) and in 18 healthy controls using perfusion fluid and biopsies from the sigmoid colon and rectum. The released amounts of the neutrophil granule proteins HNL and myeloperoxidase (MPO) were determined by radioimmunoassays, and the location of HNL and MPO in biopsies from colonic mucosa was examined by immunohistochemistry. Results: Mucosal release of HNL and MPO was increased 10–55-fold in patients with colitis and proctitis compared with controls. Their bowel biopsies demonstrated that only neutrophils were stained with anti-HNL. We also found correlations between HNL and levels of granulocyte/macrophage-colony stimulating factor (GM-CSF) and interleukin 8 (IL-8) in perfusion fluids from the sigmoidal segments of patients with proctitis, between HNL and GM-CSF in rectal segments in patients with proctitis, and in sigmoidal segments in patients with colitis. Conclusion: We conclude that the increased release of HNL and MPO in colorectal perfusion fluids indicates neutrophil involvement in the local inflammatory process, and suggest that HNL may serve as a specific marker of intestinal neutrophil activation in UC. GM-CSF, and to some extent IL-8, may play a role in neutrophil accumulation and priming in this disease.

Neutrophil mucosal involvement is accompanied by enhanced local production of interleukin-8 in ulcerative colitis.

The concentration of myeloperoxidase, a neutrophil granule constituent, was measured in the perfusion fluid from sigmoid and rectal segments in patients with ulcerative colitis. The concentrations of myeloperoxidase were increased severalfold in the patients with ulcerative colitis compared with healthy controls pointing to an enhanced neutrophil activity. The release of myeloperoxidase correlated to an enhanced local release of the neutrophil activating peptide interleukin-8 (IL-8). Increased values of tumour necrosis factor (TNF-alpha) were also found during intestinal perfusion of the patients and correlated with those of IL-8. The results obtained are compatible with the hypothesis that local mucosal recruitment/activation of neutrophils in ulcerative colitis is mediated by an enhanced IL-8 synthesis. TNF-alpha may be one relevant factor as a stimulus to IL-8 synthesis.

Enhancement of factor XII dependent reactions by eosinophil cationic protein

Abstract The cationic protein derived from the granules of human eosinophil granulocytes (ECP) shortened the coagulation time of normal plasma in a time and dose dependent manner. The stimulating effect of ECP could not be brought about in plasma deficient of the factor XII. ECP also enhanced the formation of plasma-kallikrein activity upon glass activation of normal plasma. The lowest effective concentrations of ECP for both reactions were approximately 100 μg/l plasma. The results suggest a role of the eosinophil granulocyte in factor XII-dependent reactions.