title: Taurine transporter gene expression in peripheral mononuclear blood cells of type 2 diabetic patients.
abstract: Taurine acts as antioxidant, cell osmolyte, modulator of glucose metabolism, and plays a role in the retinal function. It is 10(3)-fold more concentrated in the intracellular than in the extracellular milieu due to a specific taurine-Na-dependent transporter (TauT), which is upregulated by hypertonicity, low extracellular taurine, or oxidative stress and acutely downregulated 'in vitro' by high glucose concentrations. Aim of this study was to investigate whether TauT expression was modified in mononuclear peripheral blood cells (MPC) of type 2 diabetic patients with or without micro/macrovascular complications. Plasma taurine, as well as other sulphur-containing aminoacids (assayed by HPLC) and TauT gene expression (assayed by real-time PCR analysis) were measured in MPC of 45 controls and of 81 age-and-sex matched type 2 diabetic patients with or without micro/macrovascular complications. Median value (interquartile range) of plasma taurine was significantly lower in diabetic patients than in controls [28.7 (13.7) μmol/l vs. 46.5 (20.3) μmol/l; P<0.05], while median TauT expression, in arbitrary units, was significantly higher in diabetics than in controls [3.8 (3.9) vs. 1 (1.3); P<0.05) and was related to HbA1c only in controls (r=0.34; P<0.05). Patients with retinopathy (n=25) had lower TauT expression than those who were unaffected [3.1 (2.8) vs. 4.1 (3.4); P<0.05], while persistent micro/macroalbuminuria was associated with unchanged TauT expression. A trend toward reduction in TauT expression was observed in patients with macroangiopathy [n=27; 3.3 (2.5) vs. 4 [3.7]; P=NS]. In conclusion, TauT gene is overexpressed in MPC of type 2 diabetic patients, while presence of retinopathy is specifically associated with a drop in TauT overexpression, suggesting its possible involvement in this microangiopathic lesion.
authors: Department of Clinical Chemistry, Spedali Riuniti, Pistoia, Italy.
authors: Loria
authors: L
authors: Bianchi
authors: Riccardo
authors: R
authors: Lari
authors: Roberto
authors: R
authors: Anichini
authors: Alessandra
authors: A
authors: De Bellis
authors: Angela
authors: A
authors: Berti
authors: Zaleida
authors: Z
authors: Napoli
authors: Giuseppe
authors: G
authors: Seghieri
authors: Flavia
authors: F
authors: Franconi
mesh_terms: D000368:Aged; D000419:Albuminuria / Q000097:blood* / Q000150:complications / Q000235:genetics; D000603:Amino Acids, Sulfur / Q000097:blood; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000150:complications / Q000235:genetics; D003930:Diabetic Retinopathy / Q000097:blood* / Q000150:complications / Q000235:genetics; D005260:Female; D015870:Gene Expression; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007558:Italy; D007963:Leukocytes, Mononuclear / Q000378:metabolism / Q000473:pathology; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D013654:Taurine / Q000097:blood; D000099247:Taurine Transporters
chemical_list: D000603:Amino Acids, Sulfur; D006442:Glycated Hemoglobin; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D013654:Taurine; D000099247:Taurine Transporters; C517652:hemoglobin A1c protein, human