Plasma levels of MASP-1, MASP-3 and MAp44 in patients with type 2 diabetes: influence of glycaemic control, body composition and polymorphisms in the MASP1 gene

Clin Exp Immunol. 2017 Jul;189(1):103-112. doi: 10.1111/cei.12963. Epub 2017 Apr 20.


Mounting evidence indicates that adverse activation of the complement system plays a role in the development of diabetic vascular complications. Plasma levels of the complement proteins mannan-binding lectin (MBL) and its associated serine proteases (MASP-1 and MASP-2) are elevated in diabetes. We hypothesized that single nucleotide polymorphisms (SNPs) in the MASP1 gene may contribute to altered plasma levels of the belonging gene products; MASP-1, MASP-3 and mannan-binding lectin-associated protein of 44 kDa (MAp44) in patients with type 2 diabetes. To investigate this, we compared plasma levels of MASP-1, MASP-3 and MAp44 in 100 patients with type 2 diabetes and 100 sex- and age-matched controls. Ten carefully selected SNPs were analysed using TaqMan® genotyping assay. Additionally, we included a streptozotocin-induced diabetes mouse model to directly examine the effect of inducing diabetes on MASP-1 levels. MASP-1 levels were significantly higher among patients with type 2 diabetes compared with healthy controls (P = 0·017). Five SNPs (rs874603, rs72549254, rs3774275, rs67143992, rs850312) in the MASP1 gene were associated with plasma levels of MASP-1, MASP-3 and MAp44. In the diabetes mouse model, diabetic mice had significantly higher MASP-1 levels than control mice (P = 0·003). In conclusion, MASP-1 levels were higher among patients with type 2 diabetes and diabetic mice. The mechanism behind this increase remains elusive.

Keywords: complement; mannan-binding lectin-associated serine proteases; single nucleotide polymorphism; type 2 diabetes mellitus.

MeSH terms

  • Aged
  • Animals
  • Blood Glucose
  • Body Composition*
  • Case-Control Studies
  • Denmark
  • Diabetes Mellitus, Experimental
  • Diabetes Mellitus, Type 2 / blood*
  • Female
  • Genotype
  • Humans
  • Linear Models
  • Male
  • Mannose-Binding Lectin / blood*
  • Mannose-Binding Protein-Associated Serine Proteases / analysis*
  • Mannose-Binding Protein-Associated Serine Proteases / genetics
  • Mice
  • Mice, Inbred C57BL
  • Middle Aged
  • Polymorphism, Single Nucleotide
  • Streptozocin


  • Blood Glucose
  • Mannose-Binding Lectin
  • Streptozocin
  • MASP1 protein, human
  • Mannose-Binding Protein-Associated Serine Proteases