Activin A as a marker of intrauterine infection in women with preterm prelabour rupture of membranes

Amniotic fluid proteomic signatures of cervical insufficiency and their association with length of latency

PROBLEM

Cervical insufficiency is a precursor of preterm birth. Treatment with emergency cervical cerclage is contraindicated in the presence of intra-amniotic infection. Detecting infection with Gram stain and culture of amniotic fluid lacks sensitivity. Proteomic profiling of amniotic fluid in cervical insufficiency may help identify pregnancies best suited for emergency cerclage.

METHOD OF STUDY

Thirty-two pregnant women underwent amniocentesis for routine genetic testing (n = 22) or after diagnosis of cervical insufficiency (n = 10). The proteomic profiles of the amniotic fluid samples were compared in a cross-sectional fashion, including sub-analyses of women with cervical insufficiency and latency periods of <1 week and >1 week post-diagnosis.

RESULTS

Mean gestational age at diagnosis of cervical insufficiency was 21.4 weeks (95% CI 20.6-22.1). Proteomic analysis yielded 40 (7.2%, P < 0.05) differentially expressed proteins between women with delivery <1 week (n = 6) vs. >1 week (n = 4). Women who delivered <1 week had activated inflammatory response (z = 2.3, P = 6.71E-09), chemotaxis of immune cells (z = 2.9, P = 2.01E-08), and inhibited bacterial growth (z = -2.2, P = 5.82E-05). A multivariate model of eight biomarkers positively associated with cases of <1 week latency and distinguished cases from controls (97.8%, cross-validation accuracy 92.7%, P = 0.0009).

CONCLUSION

In this pilot study, significant differences in the amniotic fluid proteomic profiles in cases of cervical insufficiency compared to genetic amniocentesis were observed. Proteomic signatures were predictive of achieving latency > 1 week after diagnosis of cervical insufficiency. These preliminary findings suggest that proteomic analysis may be of value in predicting outcome following cervical insufficiency and warrants further validation in larger studies.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.