Metformin, but not glimepiride, improves carotid artery diameter and blood flow in patients with type 2 diabetes mellitus.
OBJECTIVE
To compare the effects of glimepiride and metformin on vascular reactivity, hemostatic factors and glucose and lipid profiles in patients with type 2 diabetes.


METHODS
A prospective study was performed in 16 uncontrolled patients with diabetes previously treated with dietary intervention. The participants were randomized into metformin or glimepiride therapy groups. After four months, the patients were crossed over with no washout period to the alternative treatment for an additional four-month period on similar dosage schedules. The following variables were assessed before and after four months of each treatment: 1) fasting glycemia, insulin, catecholamines, lipid profiles and HbA1 levels; 2) t-PA and PAI-1 (antigen and activity), platelet aggregation and fibrinogen and plasminogen levels; and 3) the flow indices of the carotid and brachial arteries. In addition, at the end of each period, a 12-hour metabolic profile was obtained after fasting and every 2 hours thereafter.


RESULTS
Both therapies resulted in similar decreases in fasting glucose, triglyceride and norepinephrine levels, and they increased the fibrinolytic factor plasminogen but decreased t-PA activity. Metformin caused lower insulin and pro-insulin levels and higher glucagon levels and increased systolic carotid diameter and blood flow. Neither metformin nor glimepiride affected endothelial-dependent or endothelial-independent vasodilation of the brachial artery.


CONCLUSIONS
Glimepiride and metformin were effective in improving glucose and lipid profiles and norepinephrine levels. Metformin afforded more protection against macrovascular diabetes complications, increased systolic carotid artery diameter and total and systolic blood flow, and decreased insulin levels. As both therapies increased plasminogen levels but reduced t-PA activity, a coagulation process was likely still ongoing.
Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Laboratory of Medical Investigation (LIM-18), São Paulo/SP, Brazil.
Helena Atroch
HA
Machado
Marcelo
M
Vieira
Maria Rosaria
MR
Cunha
Marcia Regina Soares
MR
Correia
Rosa Tsunechiro
RT
Fukui
Rosa Ferreira dos
RF
Santos
Dalva Marreiro
DM
Rocha
Bernardo Leo
BL
Wajchenberg
Silvia G
SG
Lage
Maria Elizabeth Rossi da
ME
Silva
D001786:Blood Glucose / Q000378:metabolism; D002339:Carotid Arteries / Q000187:drug effects* / Q000473:pathology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy*; D005215:Fasting / Q000097:blood; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D008055:Lipids / Q000097:blood; D008297:Male; D008687:Metformin / Q000494:pharmacology*; D008875:Middle Aged; D009929:Organ Size / Q000187:drug effects; D011446:Prospective Studies; D013453:Sulfonylurea Compounds / Q000494:pharmacology*
D001786:Blood Glucose; D007004:Hypoglycemic Agents; D008055:Lipids; D013453:Sulfonylurea Compounds; C057619:glimepiride; D008687:Metformin