title: Serum Levels of Soluble CD26/Dipeptidyl Peptidase-IV in Type 2 Diabetes Mellitus and Its Association with Metabolic Syndrome and Therapy with Antidiabetic Agents in Malaysian Subjects.
abstract: BACKGROUND
  A soluble form of CD26/dipeptidyl peptidase-IV (sCD26/DPP-IV) induces DPP-IV enzymatic activity that degrades incretin. We investigated fasting serum levels of sCD26/DPP-IV and active glucagon-like peptide-1 (GLP-1) in Malaysian patients with type 2 diabetes mellitus (T2DM) with and without metabolic syndrome (MetS), as well as the associations between sCD26/DPP-IV levels, MetS, and antidiabetic therapy.
  
  
  METHODS
  We assessed sCD26/DPP-IV levels, active GLP-1 levels, body mass index (BMI), glucose, insulin, A1c, glucose homeostasis indices, and lipid profiles in 549 Malaysian subjects (including 257 T2DM patients with MetS, 57 T2DM patients without MetS, 71 non-diabetics with MetS, and 164 control subjects without diabetes or metabolic syndrome).
  
  
  RESULTS
  Fasting serum levels of sCD26/DPP-IV were significantly higher in T2DM patients with and without MetS than in normal subjects. Likewise, sCD26/DPP-IV levels were significantly higher in patients with T2DM and MetS than in non-diabetic patients with MetS. However, active GLP-1 levels were significantly lower in T2DM patients both with and without MetS than in normal subjects. In T2DM subjects, sCD26/DPP-IV levels were associated with significantly higher A1c levels, but were significantly lower in patients using monotherapy with metformin. In addition, no significant differences in sCD26/DPP-IV levels were found between diabetic subjects with and without MetS. Furthermore, sCD26/DPP-IV levels were negatively correlated with active GLP-1 levels in T2DM patients both with and without MetS. In normal subjects, sCD26/DPP-IV levels were associated with increased BMI, cholesterol, and LDL-cholesterol (LDL-c) levels.
  
  
  CONCLUSIONS
  Serum sCD26/DPP-IV levels increased in T2DM subjects with and without MetS. Active GLP-1 levels decreased in T2DM patients both with and without MetS. In addition, sCD26/DPP-IV levels were associated with Alc levels and negatively correlated with active GLP-1 levels. Moreover, metformin monotherapy was associated with reduced sCD26/DPP-IV levels. In normal subjects, sCD26/DPP-IV levels were associated with increased BMI, cholesterol, and LDL-c.
authors.affiliation: Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Radwan H
authors.initials: RH
authors.lastname: Ahmed
authors.affiliation: Department of Pharmacy, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia; Clinical Investigation Centre, University Malaya Medical Centre, Kuala Lumpur, Malaysia.
authors.forename: Hasniza Zaman
authors.initials: HZ
authors.lastname: Huri
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Medicine, Sana'a University, Sana'a, Yemen.
authors.forename: Zaid
authors.initials: Z
authors.lastname: Al-Hamodi
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Medicine, Sana'a University, Sana'a, Yemen.
authors.forename: Sameer D
authors.initials: SD
authors.lastname: Salem
authors.affiliation: Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Sekaran
authors.initials: S
authors.lastname: Muniandy
mesh_terms: D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000150:complications / Q000188:drug therapy*; D018819:Dipeptidyl Peptidase 4 / Q000097:blood* / Q000737:chemistry*; D005215:Fasting / Q000097:blood; D005260:Female; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D008296:Malaysia; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications*; D008687:Metformin / Q000494:pharmacology / Q000627:therapeutic use; D008875:Middle Aged; D012995:Solubility
chemical_list: D018819:Dipeptidyl Peptidase 4; D052216:Glucagon-Like Peptide 1; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D008687:Metformin; C517652:hemoglobin A1c protein, human