THROMBOSIS RESEARCH Printed in the United

LOW

VASCULAR

FIBRINOLYTIC

Lars-Olof

Xedicine

ACTIVITY

IN

1975

Inc.

OBESITY

Almer and Lars Janzon

From the Coagulation Internal

vol. 6, pp. 171-175, Pergamon Press,

States

Laboratory

and the Departments

and Surgery,

Allmanna

of

Sjukhuset,

Malti, Sweden (Received

16.12.197&;

in revised form 13.1.1975. by Editor H.C. Godal)

Accepted ABSTPACT

The blood fibrinolytic activity is abnormally low in obesity. A significant correlation was found between the endothelial content of plasminoyen activator in the vessel walls and degree of overweight. It is suggested that this impairment of fibrinolysis might contribute to the high incidence of vascular complications in obesity.

INTRODUCTION Venous

thromboerrbolism

tic manifestations individuals.

(5,

7,

6,

15, 18, 20) and atherosclero-

are more common in obese than in non-obese

According

to Gordon and Rannel

cess risk of angina pectoris

(8) who found an ex-

and sudden death in obese individuals

with no known risk factors other than obesity, which

adiposity

contributes

fully established. cholesterol,

to cardiovascular

That it contributes

higher

blood pressure

incidence

by providing

and possibly

sugar seems clear, but it is not known whether unique extra morbidity

contribution".

and mortality

vessels,

because

normally

low in obesity

One possible

activity

(3, 9) for unknown 171

is not

increased

higher

blood

it makes some

in cardiovascular

lysis of fibrin deposits

the fibrinolytic

by

cause of the increased

of obese individuals

disease might be an impaired

"the mechanism

in the

of the blood reasons

(10).

is ab-

VASCULAR FIBRINOLYTIC ACTIVITY

172

vo1.6,pl'o.~

The aim of the present study was to investigate if a similar correlation does exist between overweight and the fibrinolytic activity of the vessel walls. We have previously reported a close correlation between the fibrinolytic activity of veins and arteries (4).

MATERIAL AND ivIETHODS The material consisted of a sub-sample of 110 randomly selected non-smokers and heavy smokers from the study group "Men born in 1914 and residing in Malmij" (12). In all subjects a biopsy specimen was obtained of a superficial vein on the back of the hand. The vessels were examined by the histochemical method of Todd (191, as modified by Pandolfi et al. (161, and the fibrinolytic activity determined. Four fibrin slides were prepared for each specimen and after incubation at 37OC for 0, 10, 20, and 30 minutes, the fibrinolytic activity was measured as the lysed areas in the fibrin film. Three fairly distinct degrees of fibrin digestion were recognized, namely grade I: microscopical punctate areas of lysis in most of the sections; grade II: gross lytic areas of irregular outline and sometimes confluent; grade III: dissolution of most or all the fibrin in contact with the sections. A grade I slide was allotted 1 point; a grade II slide, 2 points and a grade III, 3 points. Degrees of digestion between grades 0 and I, I and II, and II and III were allotted 0.5, 1.5 and 2.5 points, respectively. The total number of points scored by the set of four slides was taken as a measure of the fibrinolytic activity of the sample. The reproducibility of this system is high (17). with the use of height/weight tables (1) based on American data (11) as ideal weight, the patients were separated into four groups: A B C"" D

actual weight " " "

II

below o- 9.9 % above 10 - 19.9 % " )I 320 %

ideal weight " II II n II II

VASCULAR

v01.6,~0.2

FIBRINOLYTIC

-1 73

ACTIVITY

RESULTS The activator activity ranged between 1.5 and 10.0 arbitrary units. When the patients in the different weight groups were separated into those with 7 or more arbitrary units of activator activity and those with lower activity, it was found that there were significantly more patients (chi square test p