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