Levels of protein S during the normal menstrual cycle and in women on oral contraceptives low in estrogen

Frequency of protein S deficiency in general Japanese population

We measured protein S (PS) activity in a large group of Japanese subjects to study the frequency of PS deficiency. The study group comprised 213 men, ages 18-58 years, and 179 women, ages 18-60 years. PS activity in the total 392 subjects was 58-135% (mean +/- 2 SD), 65-135% in the men and 54-120% in the women. The men showed significantly higher levels of PS activity than the women (p<0.001). We identified 8 subjects (4 men and 4 women) in whom PS activity was lower than the mean-2SD for men and women, respectively. Moreover, we examined the classifications of PS deficiency. The frequency of PS deficiency in this study was 2.04% (Type I: 0.51%, Type II: 1.02%, Type III: 0.51%). Based on our findings, it would appear that the frequency of Type II PS deficiency in the Japanese population is approximately 1%. The screening of PS decrease should be judged by activity.

Plasma resistance to activated protein C regulates the activation of coagulation induced by thrombolysis in patients with ischaemic heart disease

OBJECTIVE

To determine whether there was a relation between plasma resistance to activated protein C and the coagulation activation induced during thrombolysis with 100 mg alteplase in 25 patients with acute ischaemic heart disease.

METHODS

Blood samples were collected before (t = 0 h), during (t = 2.25 h), and after (t = 4 h, t = 12 h, and t = 24 h) thrombolysis to examine the relation between baseline activated protein C resistance ratio and markers of coagulation activation-that is, thrombinantithrombin III-complexes and prothrombin fragment 1 + 2 generated during thrombolysis.

RESULTS

There was a negative correlation between activated protein C resistance ratio and area under the curve of thrombin-antithrombin III-complexes (rs = - 0.60; P < 0.003) and there was a trend to a negative correlation between activated protein C resistance ratio and area under the curve of prothrombin fragment 1 + 2 (rs = - 0.37; P = 0.07). This accorded with the negative correlation between activated protein C resistance ratio and the peak value of thrombin-antithrombin III-complexes (rs = - 0.55; P < 0.005) and between activated protein C resistance ratio and the peak value of prothrombin fragment 1 + 2 (rs = - 0.42; P < 0.04). Components of the protein C/S system or known inhibitors of activated protein C may influence the activated protein C resistance ratio. There were no associations between the activated protein C resistance ratio and protein C, protein C inhibitor, or plasminogen activator inhibitor type-1, whereas there was a trend to a negative correlation between activated protein C resistance ratio and protein S.

CONCLUSIONS

The results indicate that plasma resistance to activated protein C may be one of the main mechanisms regulating the activation of coagulation induced by thrombolysis. This study suggests that it may be possible to single out individuals with a high risk of reocclusion before the start of thrombolytic therapy.

Protein S levels during the normal menstrual cycle and during estrogen therapy for premature ovarian failure

Protein S levels have been reported to be decreased in pregnancy and with oral contraceptive use. This study monitored the effects of estrogen shifts on protein S levels. Four patients with premature ovarian failure were treated with either oral or transdermal patch estrogen replacement. Blood drawn on days 1, 14, and 28 of therapy was analyzed for estradiol, estrone, free and total protein S, and C4b-binding protein (C4b-BP) levels. Similar studies were performed on six normally cycling control patients and seven postmenopausal women. In healthy females, total levels of protein S fell from 22.1 +/- 0.73 micrograms/mL on day 1 to 19.2 +/- 1.29 micrograms/mL on day 14 (p < 0.023). Free protein S levels declined from 6.45 +/- 0.70 micrograms/mL to 5.59 +/- 0.69 micrograms/mL (p < 0.016). C4b-BP levels did not change during the normal menstrual cycle. Baseline total protein S (44.1 +/- 7.0 micrograms/mL) and C4b-BP (193 +/- 18%) levels were elevated in patients with premature ovarian failure. On oral therapy, there was a strong, negative correlation (r = -0.979, p < 0.021) between C4b-BP and estradiol levels. C4b-BP levels did not change in patients with the patch. Both estrogen therapies produced similar declines (44 to 26 micrograms/mL) in total protein S levels. In all cases, total protein S levels changed as a reciprocal function of estradiol. C4b-BP (128 +/- 6.5%) and total protein S (32.2 +/- 3.0 micrograms/mL) levels were higher in postmenopausal women than in nonmenopausal females. Free protein S levels in postmenopausal women (9.6 +/- 0.6 micrograms/mL) were normal.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of monophasic low-dose oral contraceptives on fibrin formation and resolution in young women

OBJECTIVE

The purpose of this study was to examine key variables in the regulation of coagulation and fibrinolysis during intake of low-dose oral contraceptives containing newly developed progestogens.

STUDY DESIGN

Thirty-four healthy young women were allocated to 12 consecutive cycles of treatment with monophasic combinations of 20 micrograms ethinyl estradiol and 150 micrograms desogestrel (n = 15) or 30 micrograms ethinyl estradiol and 75 micrograms gestodene (n = 19). Nonparametric analysis of variance was used for statistical evaluation.

RESULTS

In both groups plasma levels of fibrinogen and Factor VIIc increased, and the capacity of coagulation inhibition was affected by increased protein C and decreased protein S levels. Increased fibrinolytic capacity was indicated by elevated activity and reduced antigen levels of tissue plasminogen activator and by reduced activity and concentration of plasminogen activator inhibitor. Thrombin-antithrombin III complexes and fibrin degradation products were unchanged, signifying no effect of hormonal intake on the degree of activation of the coagulation system or the efficacy of fibrinolysis.

CONCLUSION

The overall dynamic balance between generation and resolution of fibrin was maintained during treatment with both hormonal compounds. Our findings suggest that the risk of thrombosis in normal women should not be increased.

Effects of newer oral contraceptives on the inhibition of coagulation and fibrinolysis in relation to dosage and type of steroid

Oral contraceptives influence plasma proteins, causing changes in plasma procoagulants and fibrinolytic effectors. Estrogen is thought to be responsible for these changes, whereas progestogens, in particular those with an androgenic effect, may influence the magnitude of the changes. This concept is consistent with epidemiologic studies, suggesting a correlation between estrogen dose and cardiovascular episodes in oral contraceptive users. A delayed resolution of fibrin might contribute to an increased risk caused by decreased coagulation inhibition or fibrinolytic efficacy. Estrogen (30 micrograms or more) has a dose-dependent effect on clotting factors, including antithrombin III and proteins C and S. The effect of high- and low-dose oral contraceptives containing various progestogens on the fibrinolytic system is less clear. We have found that low-dose oral contraceptives containing levonorgestrel or lynestrenol enhance fibrinolysis, as revealed by an increase in plasminogen (30% to 40%), a decrease in histidine-rich glycoprotein (15% to 26%), an increase in tissue plasminogen activator activity (greater than 150%), and a decrease in tissue plasminogen activator inhibition (30% to 40%), concomitant with a slight decrease in tissue plasminogen activator antigen level (15% to 20%). New oral contraceptives contain less androgenic progestogens. Preliminary results of an ongoing study of women receiving either 20 micrograms of ethinyl estradiol with 150 micrograms of desogestrel or 30 micrograms of ethinyl estradiol plus 75 micrograms of gestodene revealed no change or changes similar to the older low-dose preparations after 6 months of treatment. Of particular importance was the finding that coagulation activation, expressed by the levels of thrombin-antithrombin III-complexes, fibrin formation, and the efficacy of fibrinolysis, expressed by the levels of fibrin degradation products, was identical in the two groups.