Download - 629: The use of diffusion-weighted MRI to study in-vivo fetal lung maturation in a rabbit model

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www.AJOG.org SMFM Abstracts

29 THE USE OF DIFFUSION-WEIGHTED MRI TO STUDY IN-VIVO FETAL LUNG MATURATIONIN A RABBIT MODEL SCOTT PETERSEN1, RONALD PEETERS2, FREDERIK DE KEYZER2,JAN DEPREST1, FILIP CLAUS2, 1Katholieke Universiteit Leuven, Centre for SurgicalTechnologies, Leuven, Belgium, 2Katholieke Universiteit Leuven, Radiology, Leu-ven, Belgium

OBJECTIVE: To determine if diffusion-weighted magnetic resonance imaging(DWI-MRI) can be used to assess prenatal lung growth and maturation in a rabbitmodel. Lung development of rabbits mimicks that of humans, with in utero alve-olization.

STUDY DESIGN: Four pregnant healthy Flemish Giant does were imaged usinga 3 Tesla MRI scanner (Magnetom Trio, Siemens, Erlangen, Germany) at differentstages of lung development: d25 (canalicular phase), d27 (canalicular phase), d29(saccular phase) and d30 (alveolar phase - term�31-32d). Rabbits were sedated andscanned supine using an 8 channel knee coil. T2-weighted single-shot turbospin-echo imaging (TR/TE�1200/68ms, voxel size�1.0x0.8x2.0mm) was performed foranatomical referencing and intra-uterine localization of the fetuses. Diffusion-weighted MR images (DWI-MRI) were obtained with following parameters: TR/TE�10300/80ms, b-values�0-50-250-500-750-1000s/mm2, voxel size1.4x1.2x3.0mm. Regions of interest (ROI) were manually drawn in all fetal lungs,signal intensities for all b-values were recorded, and apparent diffusion coefficients(ADC) were calculated for all measurements. Linear regression analysis was used toassess the relationship between gestational age, the signal intensity for all b-valuesand the calculated ADC values.

RESULTS: The number of fetuses per mother ranged between 6 and 11 (31fetuses in total). DWI-MRI measurements were possible for 27 fetuses (�87%).The number of pixels for the ROI=s ranged between 12 and 22 (�0.20-0.37cm2). Astatistically significant (p�0.001) decrease in signal intensity was observed in lungsduring gestation on all diffusion-weighted images. No correlation was found be-tween the ADC-values and gestational age at MRI (p�0.77).

CONCLUSION: DWI-MRI enables to detect statistically significant changes insignal intensities in normal fetal lungs as pregnancy progresses.

0002-9378/$ - see front matterdoi:10.1016/j.ajog.2008.09.659

30 THROMBOXANE A2 FORMATION IN PREGNANCIES COMPLICATED BY INTRAUTERINEGROWTH RESTRICTION CAOIMHE LYNCH1, BERNARD STUART1, ACHIM TREUMANN2,RONAN CONROY2, CARMEN REGAN1, 1Coombe Women and Infants University Hospi-tal, Dublin, Ireland, 2Royal College of Surgeons in Ireland, Dublin, Ireland

OBJECTIVE: To establish whether pregnancy complicated by intrauterinegrowth restriction (IUGR) with abnormal umbilical artery Doppler (UAD) is as-sociated with an increased formation of thromboxane A2 (TxA2).

STUDY DESIGN: A prospective case-controlled study was performed. Inclusioncriteria were singleton pregnancy, foetal abdominal circumference 5th centile forgestational age, normal foetal anatomy and karyotype. A control group of gesta-tional age matched appropriately grown normal foetuses were enrolled. Maternalurine samples were collected at two weekly intervals until delivery. Quantitation ofthe stable urinary metabolite of TxA2, 11-dehydrothroboxane B2, was performedusing high performance liquid chromatography mass spectrometry. Levels of 11-dehydrothromboxane B2 were transformed to a log-10 scale before analysis, result-ing in a normal distribution. Regression with robust variance estimation to correctfor the use of multiple measures from the same patient were used to model throm-boxane levels as a function of IUGR.

RESULTS: Twenty-four patients were enrolled with documented IUGR, ofthese fourteen had abnormal UAD measurements. Eleven patients were enrolled ascontrols. IUGR with abnormal UAD was associated with a significantly lower levelof 11-dehydrothromboxane production (mean log-10 1788.6 pg/mg creatinine)compared to IUGR with normal UAD (mean log-10 3575.4 pg/mg creatinine)(P�0.009) and normal size controls (mean log-10 3136.4 pg/mg creatinine)(P�0.007). There was no significant difference between IUGR with normal UADand normal size controls (P�0.918).

CONCLUSION: The use of low dose aspirin in IUGR is based on the premise ofincreased formation of TxA2 in this condition. In contrast our study showed re-duced TxA2 formation in severe IUGR. This may reflect impaired placental func-tion in severe IUGR and does not support the use of low dose aspirin therapy in themanagement of this condition.


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31 PREGNANCY-SPECIFIC MODULATIONS IN MATERNAL PLASMA PROTEINGLYCOSYLATION PATTERNS DANIELLE L. IPPOLITO1, JONATHAN D. STALLINGS1, LISAM. FOGLIA2, PETER G. NAPOLITANO2, MICHAEL J. HARTENSTINE1, 1Madigan Army Med-ical Center, Clinical Investigation, Tacoma, Washington, 2Madigan Army MedicalCenter, Maternal Fetal Medicine, Tacoma, Washington

OBJECTIVE: Recent investigation of the pregnancy glycoproteome highlightsthe potential diagnostic utility of the information encoded within the post transla-tional modifications of plasma proteins in pregnancy and disease states. Here wepresent a mass spectrometry-based approach examining modulation in maternalplasma protein glycosylation status during pregnancy.

STUDY DESIGN: Blood was obtained from 200 nulliparas at 5 gestational ageranges per patient. We monitored the glycosylation status of intact proteins inmaternal plasma during gestation by a top-down surface-enhanced laser desorp-tion ionization mass spectrometry proteomic profiling approach and further char-acterized glycoproteins of interest by gel electrophoresis and glycan immunoassay.

RESULTS: The most significant gestationally correlated modulations in mater-nal SELDI-TOF MS profiles corresponded with the 8-10kDa region of the spectra.The relative abundance of spectral features at 9.1 and 9.4kDa increased exponen-tially through pregnancy, then declined post-partum. The 9.1 and 9.4kDa proteinswere lower in fetal cord blood at parturition relative to maternal blood, suggestinga maternal origin. Further, the ratio of the 9.4kDa protein to the 9.1kDa peakincreased exponentially as pregnancy progressed. Glycosidase treatment collapsedthe 9.1kDa and 9.4kDa proteins to a single peak at approximately 8.8kDa. Treat-ment with o-linked glycosidase alone had no effect on spectral profile, whereasneuraminidase shifted the predominant 9.4kDa peak by 0.3kDa to 9.1kDa. Com-bining o-glycosidase and neuraminidase shifted the 9.1kDa peak a further 0.3kDato approximately 8.8kDa. Both shifts were accompanied by an additive fold-changein relative peak abundance.

CONCLUSION: A literature review suggests an identity of apolipoprotein CIII forthese peaks. ApoCIII is a high abundance, 8.8kDa protein with an O-linked glyco-sylation site at threonine 74 and three sialyated forms reported. This protein is notonly elevated in pregnancy, but it has also been reported to be elevated in hyper-tensive disorders such as preeclampsia.


32 DOXYCYCLINE MATRIX METALLOPROTEASE INHIBITION AFFECTS LUNG GROWTH INTHE NITROFEN RAT MODEL FOR PULMONARY HYPOPLASIA SCOTT PETERSEN1,STEFFI MAYER1, PHILIPP KLARITSCH1, VERONIKA BECK1, JAN DEPREST1, 1Katholieke Uni-versiteit Leuven, Center for Surgical Technologies, Leuven, Belgium

OBJECTIVE: To test the hypothesis that maternal administration of a matrixmetalloprotease (MMP) inhibitor during pregnancy affects fetal lung developmentin the rat nitrofen model for pulmonary hypoplasia.

STUDY DESIGN: Pregnant Wistar rats were first gavage fed either 100mg nitro-fen in 1 mL olive oil (OO) or OO only on E9.5, following which either doxycyclinehyclate 2 mg/mL or nothing was added to the drinking water (Table1). Fetuses wereharvested on E21.5 to determine wet body, lung, liver and placenta weights. Leftfetal lungs were snap frozen at �80°C for quantitative real-time PCR (SYBR GreenKit, Invitrogen, USA), performed to assess mRNA expression of MMP-2,VEGF-A,SP-C and Ki67; GAPDH serving as the housekeeping gene.

RESULTS: In OO-exposed rats doxycycline in drinking water did not affect lunggrowth. In contrast, doxycycline reduced lung to body weight ratio in the nitrofenexposed rats. This effect was present in nitrofen rats with (0.014 vs 0.018, p � 0,004)or without (0.021 vs 0.023, p �0.034) diaphragmatic defect. In OO-exposed rats,there was a significant difference in MMP-2 expression only between control anddoxycyline groups. In nitrofen rats however, mRNA expression was different for the4 genes assessed in the doxycycline group. The effect of doxycycline on mRNAexpression was different between the OO-exposed and nitrofen exposed rats.

CONCLUSION: Giving Doxycycline into the drinking water from Day 10.5 has adetrimental effect on lung growth in the rat nitrofen-model.


t to DECEMBER 2008 American Journal of Obstetrics & Gynecology S181