Proinsulin, intact insulin, and fibrinolytic variables and fibrinogen in healthy subjects. A population study.
OBJECTIVE
As high serum insulin predicts impaired fibrinolysis and proinsulin reacts in most conventional insulin assays, we hypothesized that proinsulin could link low fibrinolytic activity and hyperinsulinemic conditions.


METHODS
We explored the relationship between fibrinolysis and plasma fibrinogen on the one hand and specific insulin and proinsulin on the other, in a healthy population sample of 165 men and women, 25-74 years of age, from the Northern Sweden MONICA (Monitoring of Trends and Determinants in Cardiovascular Disease) Study. Specific insulin and proinsulin were measured by enzyme-linked immunosorbent assay. Partial correlation coefficients, adjusted for age and sex, were calculated.


RESULTS
Plasma fibrinogen levels were related to insulin (r = 0.25, P < 0.01) and proinsulin (r = 0.29, P < 0.001), as was plasminogen activator inhibitor (PAI)-1 activity (r = 0.36 and r = 0.29, respectively; P < 0.001). Tissue Plasminogen activator (tPA) activity correlated inversely to insulin (r = 0.35, P < 0.001) and proinsulin (r = - 0.36, P < 0.001). In a multivariate analysis taking also smoking and anthropometric and metabolic measurements into account, fasting proinsulin was a significant predictor of high plasma fibrinogen level. Insulin and proinsulin levels were not related to tPA activity. High levels of postload insulin, triglycerides, and diastolic blood pressure, but not proinsulin, predicted high PAI-l activity.


CONCLUSIONS
In a healthy population, the relationship previously described between high insulin levels and impaired fibrinolysis is not attributable to confounding from proinsulin. Elevated proinsulin levels are associated with high fibrinogen levels.
Eliasson
M
M
Department of Medicine, Luleå Hospital, Sweden. mats.eliasson@nll.se
Røder
M E
ME
Dinesen
B
B
Evrin
P E
PE
Lindahl
B
B
D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000097:blood / Q000209:etiology / Q000503:physiopathology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005340:Fibrinogen / Q000378:metabolism*; D005342:Fibrinolysis / Q000502:physiology; D018149:Glucose Intolerance / Q000097:blood / Q000150:complications / Q000175:diagnosis; D006801:Humans; D006946:Hyperinsulinism / Q000097:blood* / Q000209:etiology / Q000503:physiopathology; D007328:Insulin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood*; D011384:Proinsulin / Q000097:blood*; D011897:Random Allocation; D012307:Risk Factors; D013548:Sweden; D010959:Tissue Plasminogen Activator / Q000097:blood*
D007328:Insulin; D017395:Plasminogen Activator Inhibitor 1; D005340:Fibrinogen; D011384:Proinsulin; D010959:Tissue Plasminogen Activator