Screening of Chorioamnionitis Using Volatile Organic Compound Detection in Exhaled Breath: A Pre-clinical Proof of Concept Study

Abstract

Chorioamnionitis is a major risk factor for preterm birth and an independent risk factor for postnatal morbidity for which currently successful therapies are lacking. Emerging evidence indicates that the timing and duration of intra-amniotic infections are crucial determinants for the stage of developmental injury at birth. Insight into the dynamical changes of organ injury after the onset of chorioamnionitis revealed novel therapeutic windows of opportunity. Importantly, successful development and implementation of therapies in clinical care is currently impeded by a lack of diagnostic tools for early (prenatal) detection and surveillance of intra-amniotic infections. In the current study we questioned whether an intra-amniotic infection could be accurately diagnosed by a specific volatile organic compound (VOC) profile in exhaled breath of pregnant sheep. For this purpose pregnant Texel ewes were inoculated intra-amniotically with Ureaplasma parvum and serial collections of exhaled breath were performed for 6 days. Ureaplasma parvum infection induced a distinct VOC-signature in expired breath of pregnant sheep that was significantly different between day 0 and 1 vs. day 5 and 6. Based on a profile of only 15 discriminatory volatiles, animals could correctly be classified as either infected (day 5 and 6) or not (day 0 and 1) with a sensitivity of 83% and a specificity of 71% and an area under the curve of 0.93. Chemical identification of these distinct VOCs revealed the presence of a lipid peroxidation marker nonanal and various hydrocarbons including n-undecane and n-dodecane. These data indicate that intra-amniotic infections can be detected by VOC analyses of exhaled breath and might provide insight into temporal dynamics of intra-amniotic infection and its underlying pathways. In particular, several of these volatiles are associated with enhanced oxidative stress and undecane and dodecane have been reported as predictive biomarker of spontaneous preterm birth in humans. Applying VOC analysis for the early detection of intra-amniotic infections will lead to appropriate surveillance of these high-risk pregnancies, thereby facilitating appropriate clinical course of action including early treatment of preventative measures for pre-maturity-associated morbidities.

Detection of spontaneous preterm birth by maternal urinary volatile organic compound analysis: A prospective cohort study

“…Until now, the diagnosis of UTI based upon positive bacterial urine culture takes several days, while chorioamnionitis can only be determined postnatally. A previous study, based on VOCs of exhaled breath, demonstrated that pregnant sheep intra-amniotically inoculated with Ureaplasma parvum could be classified as having chorioamnionitis compared to those without (with a sensitivity of 0.83, a specificity of 0.71 and an AUC of 0.93) ( 22 ). Also, UTI samples could be distinguished from non-UTI samples based on VOCs ( 16 ).…”

“…Also, UTI seem to be associated with specific urinary VOC profiles that can be used to discriminate between UTI and non-UTI ( 16 , 21 ). Another recent study used VOC analyses in the exhaled breath of pregnant sheep to diagnose intra-uterine infections ( 22 ). Chorioamnionitis was further detected using VOC profiles in the amniotic fluid of time-mated ewes ( 23 ).…”

“…Chorioamnionitis was further detected using VOC profiles in the amniotic fluid of time-mated ewes ( 23 ). Uncovering microbial pathways associated with specific VOCs in sPB in humans could provide more insight into the pathophysiology of PB and could hypothetically be used as predictive biomarkers ( 22 ). Since urinary collection and analyses are already part of the standard workup for pregnant women with a high risk for sPB, the use of urinary VOC profiles would provide for an easy, accessible and non-invasive technique.…”

Ureaplasma-Driven Neonatal Neuroinflammation: Novel Insights from an Ovine Model

“…At 121 or 122 days of gestation, animals received ultrasound-guided intra-amniotic injection of 5 × 10 5 color changing units of UP serovar 3 (strain HPA5 (Rowlands et al 2021 ), kindly provided by Prof. Dr. Owen B. Spiller) (UP group) or saline (control group). This concentration was shown to induce systemic organ inflammation in the ovine fetus (Ophelders et al 2021 ). Lambs were delivered via cesarean section at day 128 or 129 (term ~ 150 days) and sacrificed by an intravenous injection of 1 g pentobarbital.…”

Insights into the Black Box of Intra-Amniotic Infection and Its Impact on the Premature Lung: From Clinical and Preclinical Perspectives

“…Less invasive or non-invasive approaches are highly desired for this particular population. One pioneer preclinical study using a sheep model has demonstrated that the volatile organic compound profile in exhaled breath could successfully differentiate ewes with UP-induced IAI from non-infected ones with an AUC of 0.93 [ 141 ]. Timely detection and appropriate surveillance of high-risk pregnancies is the cornerstone of an optimized healthcare concept starting from the antenatal period, where preventive measures and treatment of prematurity-related morbidities are ideally initiated.…”