Evaluation of interleukin-6 and its soluble receptor components sIL-6R and sgp130 as markers of inflammation in inflammatory bowel diseases

Purpose

Interleukin-6 (IL-6) production and signalling are increased in the inflamed mucosa in inflammatory bowel diseases (IBD). As published serum levels of IL-6 and its soluble receptors sIL-6R and sgp130 in IBD are from small cohorts and partly contradictory, we systematically evaluated IL-6, sIL-6R and sgp130 levels as markers of disease activity in Crohn’s disease (CD) and ulcerative colitis (UC).

Methods

Consecutive adult outpatients with confirmed CD or UC were included, and their disease activity and medication were monitored. Serum from 212 CD patients (815 measurements) and 166 UC patients (514 measurements) was analysed, and 100 age-matched healthy blood donors were used as controls.

Results

IL-6 serum levels were significantly elevated in active versus inactive CD and UC, also compared with healthy controls. However, only a fraction of IBD patients showed increased serum IL-6. IL-6 levels ranged up to 32.7 ng/mL in active CD (>?5000-fold higher than in controls), but also up to 6.9 ng/mL in inactive CD. Increases in active UC (up to 195 pg/mL) and inactive UC (up to 27 pg/mL) were less pronounced. Associations between IL-6 serum levels and C-reactive protein concentrations as well as leukocyte and thrombocyte counts were observed. Median sIL-6R and sgp130 levels were only increased by up to 15%, which was considered of no diagnostic significance.

Conclusions

Only a minority of IBD patients shows elevated IL-6 serum levels. However, in these patients, IL-6 is strongly associated with disease activity. Its soluble receptors sIL-6R and sgp130 do not appear useful as biomarkers in IBD.

     

Impaired gastric emptying and altered intragastric meal distribution in diabetes mellitus related to autonomic neuropathy?

Previous studies in diabetic patients suggested a relationship between delayed gastric emptying and increased ingesta retention in either proximal or distal stomach, but the determinants underlying these abnormalities remained obscure. We aimed at assessing the impact of cardiovascular autonomic neuropathy, blood glucose concentration, long-term glycemic control, and other factors in 34 type I and 43 type II diabetic patients (ages 21–67 and 34–81 years, respectively). Emptying was slower (P < 0.04) in type I diabetic patients than in 20 healthy control subjects (ages 23–63 years). Patients with autonomic neuropathy (N = 45) had slower gastric emptying (P < 0.02) and retained more in the distal stomach (P < 0.0001) than patients without neuropathy (N = 32). Multiple regression analyses revealed that slow emptying and increased distal retention were significantly associated with autonomic neuropathy (P < 0.043, P < 0.0002), whereas blood glucose, glycemic control, diabetes duration, age, and other factors had no discernible influence. Thus, both slow emptying and increased distal ingesta retention seem primarily referable to autonomic neuropathy.     

Alpha-receptor restriction of coronary blood flow during atrial fibrillation

The effects of atrial fibrillation (AF) on coronary circulation before and after alpha-receptor blockade were studied in 14 anesthetized, open-chest dogs. AF was induced by electrical stimulation of the left atrial appendage; identical rhythmic heart rates were adjusted by left atrial pacing. During atrial pacing, coronary vascular resistance (CVR) was 0.97 +/- 0.10 mm Hg X min X 100 g/ml (resistance units [RU]), coronary blood flow (CBF) 125 +/- 14 ml/min X 100 g, and oxygen saturation 30 +/- 2%; plasma epinephrine was 193 +/- 42 pg/ml and norepinephrine 584 +/- 111 pg/ml. During AF, CVR was higher (1.16 +/- 0.11 RU, p less than 0.0005), whereas CBF (92 +/- 9 ml/min X 100 g, p less than 0.001) and coronary sinus oxygen saturation (24 +/- 2%, p less than 0.0025) were lower than during atrial pacing. When AF was induced, epinephrine increased to 333 +/- 98 pg/ml (p less than 0.05) and norepinephrine to 1,005 +/- 214 pg/ml (p less than 0.005). The large increase in plasma catecholamines suggested an activation of the sympathoadrenal system during AF. In addition, the alpha-receptor blocker phenoxybenzamine (10 mg/kg, intravenously) abolished the differences in CVR, CBF and oxygen saturation between AF and atrial pacing. The data suggest that the decrease in CBF and increase in CVR during experimentally induced AF are caused by coronary vasoconstriction, mediated by sympathetic activation of alpha receptors in the coronary vascular bed.     

Insights into Severe 5,10‐Methylenetetrahydrofolate Reductase Deficiency: Molecular Genetic and Enzymatic Characterization of 76 Patients

5,10‐Methylenetetrahydrofolate reductase (MTHFR) deficiency is the most common inherited disorder of folate metabolism and causes severe hyperhomocysteinaemia. To better understand the relationship between mutation and function, we performed molecular genetic analysis of 76 MTHFR deficient patients, followed by extensive enzymatic characterization of fibroblasts from 72 of these. A deleterious mutation was detected on each of the 152 patient alleles, with one allele harboring two mutations. Sixty five different mutations (42 novel) were detected, including a common splicing mutation (c.1542G>A) found in 21 alleles. Using an enzyme assay in the physiological direction, we found residual activity (1.7%–42% of control) in 42 cell lines, of which 28 showed reduced affinity for nicotinamide adenine dinucleotide phosphate (NADPH), one reduced affinity for methylenetetrahydrofolate, five flavin adenine dinucleotide‐responsiveness, and 24 abnormal kinetics of S‐adenosylmethionine inhibition. Missense mutations causing virtually absent activity were found exclusively in the N‐terminal catalytic domain, whereas missense mutations in the C‐terminal regulatory domain caused decreased NADPH binding and disturbed inhibition by S‐adenosylmethionine. Characterization of patients in this way provides a basis for improved diagnosis using expanded enzymatic criteria, increases understanding of the molecular basis of MTHFR dysfunction, and points to the possible role of cofactor or substrate in the treatment of patients with specific mutations.     

Development of a synthetic tissue engineered three‐dimensional printed bioceramic‐based bone graft with homogenously distributed osteoblasts and mineralizing bone matrix in vitro

Over the last decade there have been increasing efforts to develop three‐dimensional (3D) scaffolds for bone tissue engineering from bioactive ceramics with 3D printing emerging as a promising technology. The overall objective of the present study was to generate a tissue engineered synthetic bone graft with homogenously distributed osteoblasts and mineralizing bone matrix in vitro, thereby mimicking the advantageous properties of autogenous bone grafts and facilitating usage for reconstructing segmental discontinuity defects in vivo. To this end, 3D scaffolds were developed from a silica‐containing calcium alkali orthophosphate, using, first, a replica technique – the Schwartzwalder–Somers method – and, second, 3D printing, (i.e. rapid prototyping). The mechanical and physical scaffold properties and their potential to facilitate homogenous colonization by osteogenic cells and extracellular bone matrix formation throughout the porous scaffold architecture were examined. Osteoblastic cells were dynamically cultured for 7 days on both scaffold types with two different concentrations of 1.5 and 3 × 10⁹ cells/l. The amount of cells and bone matrix formed and osteogenic marker expression were evaluated using hard tissue histology, immunohistochemical and histomorphometric analysis. 3D‐printed scaffolds (RPS) exhibited more micropores, greater compressive strength and silica release. RPS seeded with 3 × 10⁹ cells/l displayed greatest cell and extracellular matrix formation, mineralization and osteocalcin expression. In conclusion, RPS displayed superior mechanical and biological properties and facilitated generating a tissue engineered synthetic bone graft in vitro, which mimics the advantageous properties of autogenous bone grafts, by containing homogenously distributed terminally differentiated osteoblasts and mineralizing bone matrix and therefore is suitable for subsequent in vivo implantation for regenerating segmental discontinuity bone defects. Copyright © 2016 John Wiley & Sons, Ltd.