Hereditary angio-oedema: effective treatment with the progestogen-only pill in a young woman

The effect of estrogen-containing birth control pills on the constituents of bradykinin expression in plasma

Background

Hereditary angioedema with C1-inhibitor deficiency (HAE-C1INH) is a rare autosomal disorder presenting with recurrent angioedema. Estrogen-containing medications trigger angioedema in some patients, and conversely, progesterone may decrease attack frequency. The mechanism by which estrogen may exacerbate angioedema in HAE-C1INH is not well characterized.

Objective

Our aim was to investigate the link between estrogen and bradykinin constituents to better understand the specific underlying triggers that may exacerbate angioedema in patients with HAE-C1INH.

Methods

As estrogen is contraindicated for patients with HAE-C1INH, females without a history of angioedema were recruited to evaluate whether estrogen-containing oral contraceptive pills (OCPs) alter plasma protein levels of bradykinin, cleaved high-molecular-weight kininogen (cHK), and activated factor XII (FXIIa). Blood (plasma) was collected before initiation of OCP administration and 3 months thereafter. High-molecular-weight kininogen (HK) was measured by ELISA and FXIIa and cHK were analyzed by Western blot analysis.

Results

A total of 12 adult females without HAE-CINH (aged <40 years) had a median baseline plasma HK level of 33,976 ng/mL. After 3 months of OCP therapy, their median HK level increased to 38,202 ng/mL. With OCPs, there was also a significant increase in level of FXIIa protein (P <.01), as well as an increase in cHK protein level.

Conclusion

This preliminary study, performed in females without HAE-C1INH, suggests that estrogen may exacerbate angioedema by increasing the production of cHK and FXIIa.

Dyslipidaemia, combined oral contraceptives use and their interaction on the risk of hypertension in Chinese women

The objective of the study was to assess the associations of dyslipidaemia, combined oral contraceptive (COC) use and their interaction on the risk of hypertension in Chinese women. In a case-control study, we evaluated 665 hypertensive women and 665 normotensive women matched on region and age in China. Hypertensive women had a higher prevalence of dyslipidaemia and higher levels of total cholesterol, triglyceride, low-density lipoprotein-cholesterol and lipoprotein a than normotensive ones (P<0.05). The risk of hypertension gradually increased with the increasing cumulative time of COC use in women (P=0.0043), especially significantly increased among those with cumulative time of COC use 15-20 and ≥20 years (adjusted odds ratio (OR)=1.46, 95% confidence interval (CI): 1.00-2.15; OR=1.49, 95% CI: 1.06-2.11), but gradually decreased from stopping use of COC (P<0.0001). The multiplicative interaction between dyslipidaemia and accumulative time of COC use ≥15 years, dyslipidaemia and family history of hypertension, or family history of hypertension and accumulative time of COC use ≥15 years was confirmed and the interaction analyses showed that they can significantly increased the risk of hypertension (adjusted OR=2.82, 95% CI: 1.59-3.27; OR=4.33, 95% CI: 3.10-6.06; OR=4.56, 95% CI: 3.07-6.77). It is concluded that dyslipidaemia, accumulative time of COC use ≥15 years and their interaction increased the risk of hypertension.

The bradykinin-degrading aminopeptidase P is increased in women taking the oral contraceptive pill

Introduction. The renin-angiotensin and kininogen-kinin hormonal systems are critically involved in regulating blood pressure and are candidates in contributing to oral contraceptive pill (OCP)-induced hypertension.Angiotensin-converting enzyme (ACE) and aminopeptidase P (AP-P) are key enzymes in these systems and are both involved in the degradation of the vasodilator bradykinin.

Methods. Circulating ACE and AP-P levels were measured by activity assay using selective fluorogenic peptide substrates in plasma samples from the Leeds Family Study. In addition, the effect of progesterone on the expression of AP-P and ACE was examined in cells.

Results. Women on the OCP had higher age-adjusted plasma AP-P (mean [95% confidence interval]) (0.27 [0.23-0.32] nmol/min/ml (n = 53)) compared with women not on the OCP (0.17 [0.16-0.19] nmol/min/ml (n = 133), p < 0.001) or males (0.19 [0.17-0.20] nmol/min/ml (n = 209), p<0.001).There were no differences in the age-adjusted plasma ACE levels among the three groups. In HepG2 cells, progesterone treatment increased the AP-P protein and mRNA expression, whereas no effect of progesterone treatment was observed for ACE.

Conclusion. Increased AP-P may result in increased breakdown of bradykinin.These data suggest that progesterone-induced increases in AP-P may contribute to the development of OCP-induced hypertension in susceptible Women.

Hereditary angioedema

PURPOSE OF REVIEW

Major advances have been made in understanding the clinical signs and symptoms, the pathophysiology and the treatment of hereditary angioedema. This disease that often begins in childhood is caused by partial absence of the plasma protein C1-inhibitor. At the present time five pharmaceutical companies are planning or conducting clinical trials of a variety of agents to treat acute attacks of this illness. Here we review our current understanding of this illness and the current approaches to treatment.

RECENT FINDINGS

This disease is often missed in childhood or confused with other illness. The clinical signs and symptoms are reviewed. The importance of the kinin generating pathway and bradykinin in causing edema has become central to our understanding of pathophysiology. The many new approaches to therapy all appear promising.

SUMMARY

Currently we have effective chronic therapy for this disease, although available drugs have real or potential difficulties in use in children. In the future it is likely that effective therapy for acute attacks of disease will become available in the US. It is important to recognize the clinical manifestations of this potentially fatal illness and to understand the therapeutic options.