Background: Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of endothelial nitric oxide synthase, which was associated with insulin resistance. Dimethylarginine dimethylaminohydrolase (DDAH) is the major determinant of plasma ADMA. Examining data from the DIAGRAM+ (Diabetes Genetics Replication And Meta-analysis), we identified a variant (rs9267551) in the DDAH2 gene nominally associated with type 2 diabetes (P = 3 x 10(-5)).Methodology/Principal Findings: initially, we assessed the functional impact of rs9267551 in human endothelial cells (HUVECs), observing that the G allele had a lower transcriptional activity resulting in reduced expression of DDAH2 and decreased NO production in primary HUVECs naturally carrying it. We then proceeded to investigate whether this variant is associated with insulin sensitivity in vivo. To this end, two cohorts of nondiabetic subjects of European ancestry were studied. In sample 1 (n = 958) insulin sensitivity was determined by the insulin sensitivity index (ISI), while in sample 2 (n = 527) it was measured with a euglycemic-hyperinsulinemic clamp. In sample 1, carriers of the GG genotype had lower ISI than carriers of the C allele (67 +/- 33 vs.79 +/- 44; P=0.003 after adjusting for age, gender, and BMI). ADMA levels were higher in subjects carrying the GG genotype than in carriers of the C allele (0.68 +/- 0.14 vs. 0.57 +/- 0.14 mu mol/l; P=0.04). In sample 2, glucose disposal was lower in GG carriers as compared with C carriers (9.3 +/- 4.1 vs. 11.0 +/- 4.2 mgxKg(-1) free fat massxmin(-1); P=0.009).Conclusions/Significance: A functional polymorphism of the DDAH2 gene may confer increased risk for type 2 diabetes by affecting insulin sensitivity throughout increased ADMA levels.

A functional variant of the dimethylarginine dimethylaminohydrolase-2 gene is associated with insulin sensitivity

Andreozzi, Francesco;Succurro, Elena;
2012-01-01

Abstract

Background: Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of endothelial nitric oxide synthase, which was associated with insulin resistance. Dimethylarginine dimethylaminohydrolase (DDAH) is the major determinant of plasma ADMA. Examining data from the DIAGRAM+ (Diabetes Genetics Replication And Meta-analysis), we identified a variant (rs9267551) in the DDAH2 gene nominally associated with type 2 diabetes (P = 3 x 10(-5)).Methodology/Principal Findings: initially, we assessed the functional impact of rs9267551 in human endothelial cells (HUVECs), observing that the G allele had a lower transcriptional activity resulting in reduced expression of DDAH2 and decreased NO production in primary HUVECs naturally carrying it. We then proceeded to investigate whether this variant is associated with insulin sensitivity in vivo. To this end, two cohorts of nondiabetic subjects of European ancestry were studied. In sample 1 (n = 958) insulin sensitivity was determined by the insulin sensitivity index (ISI), while in sample 2 (n = 527) it was measured with a euglycemic-hyperinsulinemic clamp. In sample 1, carriers of the GG genotype had lower ISI than carriers of the C allele (67 +/- 33 vs.79 +/- 44; P=0.003 after adjusting for age, gender, and BMI). ADMA levels were higher in subjects carrying the GG genotype than in carriers of the C allele (0.68 +/- 0.14 vs. 0.57 +/- 0.14 mu mol/l; P=0.04). In sample 2, glucose disposal was lower in GG carriers as compared with C carriers (9.3 +/- 4.1 vs. 11.0 +/- 4.2 mgxKg(-1) free fat massxmin(-1); P=0.009).Conclusions/Significance: A functional polymorphism of the DDAH2 gene may confer increased risk for type 2 diabetes by affecting insulin sensitivity throughout increased ADMA levels.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.12317/82510
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 16
  • ???jsp.display-item.citation.isi??? 17
social impact