Short Communication • Kurze Mitteilung • Communication brève Acta haemat. 60: 53-55 (1978)

Platelet Aggregation in Diabetic Retinopathy D raga C reter , F ira P avlotzky and H anna S avir Departments of Haemostasis and Ophthalmology, Hasharon Hospital, Petah Tiqva

Key Words. Platelet aggregation • Diabetic retinopathy • Adenosine diphosphate • Epinephrine Abstract. Platelet aggregation in diabetic retinopathy was investigated in a group of 25 patients. An enhanced activity induced by epinephrine and arachidonic acid was found in this group as compared with the controls, whereas in adenosine di­ phosphate (ADP) platelet aggregation no differences were observed. Spontaneous aggregation was found in 8°/o of the diabetic retinopathy cases.

Platelet aggregation with the classic substances adenosine diphosphate (ADP), epinephrine, thrombin, collagen and ristocetin has been described and is routinely used in hemostasis departments all over the world [3, 11, 17, 18]. Recently, the arachidonic acid and its action on platelet behavior and aggregation were studied [5, 13, 16]. Diabetic patients have been shown to have increased sensitivity of their platelets to ADP, epinephrine and arachidonic acid [1, 4-9, 12, 15]. The aim of this study was to determine the platelet aggregation of pa­ tients with diabetic retinopathy when using ADP, epinephrine and arachi­ donic acid. Materials and Methods The group of patients chosen for the laboratory hemostasis trial comprised 25 subjects with retinal findings compatible with diabetic retinopathy. 10 healthy blood bank donors were used as normal controls.

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Received: September 19, 1977; accepted: November 28, 1977.


Creter /P avlotzky/S avir

The platelet aggregation was determined by the method of Born and C ross [2], using an Evans Electroselenium (EEL) aggregation meter, model 169 with recorder. The platelet concentration was adjusted to 200,000 + 20,000/itl. Platelet-rich plasma (PRP) 0.6 ml and the following aggregating substances in a final concentration of 6.2 X 10~4 uM ADP, 6 X 10"2 km epinephrine, 3 uM arachidonic acid were used. Platelet-poor plasma was considered 100°/o, and PRP - 0°/o. The maximal percen­ tage of aggregation at 4 min was calculated. Before each determination, spontaneous aggregation was done in PRP of all patients and controls. The time for each platelet aggregation determination was 6 min.

Results and Discussion

Statistically determined platelet aggregation results presented no sig­ nificant increased sensitivity to ADP, that is 89.6 ± 4.92 in the normal group, as compared with 86.5 ± 6.27 in the diabetic retinopathy patients. Enhanced activity by epinephrine was 98.0 ± 3.65 in normals, as com­ pared with 113.61 ± 3.31 in the patients. Arachidonic acid platelet aggregation was obtained in 40°/o of the cases, as compared with the control group, which presented no activity related to this substance. In 8%> of the investigated cases with diabetic re­ tinopathy, spontaneous aggregation was also observed. Platelets from diabetic subjects synthesize PGE2 in response to ADP, epinephrine, collagen and arachidonic acid [5], It is suggested [5, 14] that in diabetes an increased prostaglandin synthetase activity exists and from this an enhanced platelet aggregation. Our results concerning the epineph­ rine and arachidonic acid platelet aggregation confirm these findings. In contrast, no different activity with ADP as compared with the normal group was found in this study. Spontaneous aggregation not related to the onset of the disease or its severity can explain the tendency of some diabetic patients to develop thrombosis. An increased synthesis of thromboxane A, [10] or a de­ creased synthesis of prostacyclin [10] can be the cause. For prediabetic states it is suggested to find a marker which will be useful to prevent the platelet abnormalities in subjects genetically predis­ posed to become diabetics. References

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1 Bensoussan, D.; L evy-T oledano, S.; P assa, P.; C aen, J., and C anivet, J.: Platelet hyperaggregation in increased plasma level of von Willebrand factor in diabetics with retinopathy. Diabetologia 11: 307-312 (1975).

Platelet Aggregation


2 Born , G. V. R. and C ross, M. J.: The aggregation of blood platelets. J. Physiol. 168: 178-195 (1963). 3 Born , G. V. R.: Current ideas on the mechanism of platelet aggregation. Ann. N.Y. Acad. Sci. 201: 4-12 (1972). 4 C olwell , J. A.; C hambers, A., and L aimins, M.: Inhibition of labile aggrega­ tion-stimulating substance (LASS) and platelet aggregation in diabetes mellitus. Diabetes 24: 684-687 (1975). 5 C olw ell , J. A.; H alushka, P. V.; Sarji, K.; L evine, J.; Sagel, J., and N air, P. R. S.: Altered platelet function in diabetes mellitus. Diabetes 25: suppl. 2, pp. 826-831 (1976). 6 C olw ell , J. A.; Sagel, J.; C rook , L.; C hambers, A., and Laimins, M.: Correla­ tion of platelet aggregation plasma factor activity and megathrombocytes in diabetic subjects with and without vascular disease. Metabolism 26: 279-285 (1977). 7 H eath, H.; Bridgen , W. D.; C anever, J. V.; P ollock, J.; H unter , P. R.; K elsey , J., and Bloom , A.: Platelet adhesiveness and aggregation in relation to diabetic retinopathy. Diabetologia 7: 308-315 (1971). 8 K waan, H. C.; C olwell , J. A.; C ruz , S.; Suwanwela, N., and D obbie, J. G.: Increased platelet aggregation in diabetes mellitus. J. Lab. clin. Med. 80: 236-246 (1972). 9 K waan, H. C.; C olwell , J. A., and S uwanwela , N.: Disseminated intravascular coagulation in diabetes mellitus, with reference to the role of increased platelet aggregation. Diabetes 21: 108-113 (1972). 10 Editorial: Prevention of thrombosis. Lancet i: 127-128 (1977). 11 Rossi, E. C. and G reen , D.: Disorders of platelet function. Med. Clins No. Am. 56: 35-46 (1972). 12 Sagel, J.; C olwell , J. A.; C rook, L., and L aimins, M.: Increased platelet aggre­ gation in early diabetes mellitus. Ann. intern. Med. 82: 733-738 (1975). 13 Silver , M. J.; S mith, J. B.; Ingf.rman, C., and Kocsis, J. J.: Arachidonic acidinduced human platelet aggregation and prostaglandin formation. Prostaglandins 4: 863-875 (1973). 14 S mith , J. B.; Ingerman, C.; K ocsis, J. J., and S ilver , M. J.: Formation of prostaglandins during the aggregation of human blood platelets. J. clin. Invest. 52: 965-969 (1973). 15 Szirtes , M.: Platelet aggregation in diabetes mellitus. Adv. Cardiol., vol.4, pp. 179-186 (Karger, Basel 1970). 16 V argaftig, B. B. and Z irnis , P.: Platelet aggregation induced by arachidonic acid is accompanied by release of potential inflammatory mediators distinct from PGE2 and PGF2. Nature new Biol. 244: 114-116 (1973). 17 V erv.ylen, J.; G aetano, G. de , and V erstraete, M.: Round-the-table conference on normal and modified platelet aggregation. Acta med. scand., suppl. 525 (1971). 18 W eiss , H. J.: Thrombocytopathia. Clins Haemat. 1: 369-381 (1971).

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D raga C reter , MSc, Department of Haemostasis, Hasharon Hospital, Petah Tiqva


Platelet aggregation in diabetic retinopathy.

Short Communication • Kurze Mitteilung • Communication brève Acta haemat. 60: 53-55 (1978) Platelet Aggregation in Diabetic Retinopathy D raga C rete...
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