title: Tumour necrosis factor-alpha and microalbuminuria in patients with inflammatory bowel disease.
abstract: OBJECTIVE
  To determine whether tumour necrosis factor-alpha (TNF-alpha) is important in the pathogenesis of microalbuminuria in patients with inflammatory bowel disease (IBD).
  
  
  METHODS
  We measured serum TNF-alpha, interleukin (IL)-6, the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) levels and microalbuminuria in 48 patients with IBD. Serum TNF-alpha was measured by enzyme-linked immunosorbent assay and microalbuminuria was measured using an immunoturbiditimetric method. Clinical disease activity was quantified using the simple index of Harvey and Bradshaw.
  
  
  RESULTS
  Microalbuminuria was more severe in patients with IBD than in controls, and in patients with active versus inactive disease. TNF-alpha levels were higher in patients with IBD than in controls (mean +/- SE 16.4 +/- 1.4 versus 6.6 +/- 1.3 pg/ml, respectively; P < 0.01) and in patients with active versus inactive IBD (means +/- SE 20.1 +/- 2 versus 12.8 +/- 2.7 pg/ml; respectively P = 0.056). Microalbuminuria correlated strongly with TNF-alpha (r = 0.60; P < 0.009), ESR (r = 0.67, P < 0.02) and CRP levels (r = 0.935, P < 0.001). TNF-alpha correlated significantly with CRP (r = 0.54, P < 0.01). IL-6 levels were raised significantly in patients with IBD (7 +/- 4 pg/ml, controls undetectable; P < 0.05). Patients with active IBD had higher IL-6 levels than those with inactive IBD (mean +/- SE 13 +/- 8 versus 0.90 +/- 0.35 pg/ml, respectively; P < 0.05). However, IL-6 levels did not correlate with microalbuminuria in patients with IBD (r = 0.105, P = 0.256).
  
  
  CONCLUSIONS
  Our findings suggest that TNF-alpha may be important in the pathogenesis of microalbuminuria in patients with IBD, possibly through TNF-induced damage to the glomerular basement membrane. The mechanism for this has not been defined but may relate to TNF-induced disruption of sulphated glycosaminoglycans.
authors.affiliation: Department of Clinical Medicine, Trinity College, Trinity Centre for Health Sciences, St James's Hospital, Dublin, Ireland.
authors.forename: N
authors.initials: N
authors.lastname: Mahmud
authors.forename: M A
authors.initials: MA
authors.lastname: O'Connell
authors.forename: J
authors.initials: J
authors.lastname: Stinson
authors.forename: M G
authors.initials: MG
authors.lastname: Goggins
authors.forename: D G
authors.initials: DG
authors.lastname: Weir
authors.forename: D
authors.initials: D
authors.lastname: Kelleher
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000419:Albuminuria / Q000150:complications*; D002097:C-Reactive Protein / Q000032:analysis; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000150:complications / Q000378:metabolism*; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D008875:Middle Aged; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis*
chemical_list: D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D002097:C-Reactive Protein