Brian Brost

Postmortem genetic testing for conventional autopsy-negative sudden unexplained death: an evaluation of different DNA extraction protocols and the feasibility of mutational analysis from archival paraffin-embedded heart tissue.

One third of autopsy-negative sudden unexplained deaths (SUDs) can be attributed to a cardiac channelopathy. Typically, paraffin-embedded tissue (PET) is the only source of DNA available for genetic analyses. We examined different DNA extraction procedures, involving 2 deparaffinization methods, 2 digestion methods, 4 laboratory-based purification methods, and 5 commercial kits. Mutational analysis involving 25 RYR2 exons was performed on PET DNA from 35 SUD cases to evaluate the feasibility of using PET DNA for genetic testing. With the best PET-DNA extraction method, an average of only two thirds of the region of interest could be evaluated. Although we initially identified 5 missense mutations in 5 of 35 SUD cases, repeated analysis failed to confirm these mutations. DNA from PET should be considered error prone and unreliable in comprehensive surveillance of SUD-associated genes. Given these shortcomings, the standard autopsy for SUD should include archiving EDTA-preserved blood or frozen tissue to facilitate postmortem genetic testing.

Long QT Syndrome–Associated Mutations in Intrauterine Fetal Death

IMPORTANCE Intrauterine fetal death or stillbirth occurs in approximately 1 out of every 160 pregnancies and accounts for 50% of all perinatal deaths. Postmortem evaluation fails to elucidate an underlying cause in many cases. Long QT syndrome (LQTS) may contribute to this problem. OBJECTIVE To determine the spectrum and prevalence of mutations in the 3 most common LQTS susceptible genes (KCNQ1, KCNH2, and SCN5A) for a cohort of unexplained cases. DESIGN, SETTING, AND PATIENTS In this case series, retrospective postmortem genetic testing was conducted on a convenience sample of 91 unexplained intrauterine fetal deaths (mean [SD] estimated gestational age at fetal death, 26.3 [8.7] weeks) that were collected from 2006-2012 by the Mayo Clinic, Rochester, Minnesota, or the Fondazione IRCCS Policlinico San Matteo, Pavia, Italy. More than 1300 ostensibly healthy individuals served as controls. In addition, publicly available exome databases were assessed for the general population frequency of identified genetic variants. MAIN OUTCOMES AND MEASURES Comprehensive mutational analyses of KCNQ1 (KV7.1, LQTS type 1), KCNH2 (HERG/KV11.1, LQTS type 2), and SCN5A (NaV1.5, LQTS type 3) were performed using denaturing high-performance liquid chromatography and direct DNA sequencing on genomic DNA extracted from decedent tissue. Functional analyses of novel mutations were performed using heterologous expression and patch-clamp recording. RESULTS The 3 putative LQTS susceptibility missense mutations (KCNQ1, p.A283T; KCNQ1, p.R397W; and KCNH2 [1b], p.R25W), with a heterozygous frequency of less than 0.05% in more than 10 000 publicly available exomes and absent in more than 1000 ethnically similar control patients, were discovered in 3 intrauterine fetal deaths (3.3% [95% CI, 0.68%-9.3%]). Both KV7.1-A283T (16-week male) and KV7.1-R397W (16-week female) mutations were associated with marked KV7.1 loss-of-function consistent with in utero LQTS type 1, whereas the HERG1b-R25W mutation (33.2-week male) exhibited a loss of function consistent with in utero LQTS type 2. In addition, 5 intrauterine fetal deaths hosted SCN5A rare nonsynonymous genetic variants (p.T220I, p.R1193Q, involving 2 cases, and p.P2006A, involving 2 cases) that conferred in vitro electrophysiological characteristics consistent with potentially proarrhythmic phenotypes. CONCLUSIONS AND RELEVANCE In this molecular genetic evaluation of 91 cases of intrauterine fetal death, missense mutations associated with LQTS susceptibility were discovered in 3 cases (3.3%) and overall, genetic variants leading to dysfunctional LQTS-associated ion channels in vitro were discovered in 8 cases (8.8%). These preliminary findings may provide insights into mechanisms of some cases of stillbirth.

Podocyturia Predates Proteinuria and Clinical Features of Preeclampsia: Longitudinal Prospective Study

Podocyturia, the shedding of live podocytes, is present at delivery in women with preeclampsia. The aim of this study was to test whether podocyturia is present earlier in pregnancy and predicts for preeclampsia. We also aimed to compare test characteristics of podocyturia with those of angiogenic factors previously implicated in the pathogenesis of this disorder. We prospectively enrolled 315 women who provided blood and urine samples at the end of the second trimesters of their pregnancies (median, 27 gestational weeks) and within 24 hours of their deliveries (median, 39.5 gestational weeks). Blood samples were analyzed for angiogenic markers, including placental growth factor, the soluble receptor fms-like tyrosine kinase receptor-1 for vascular endothelial growth factor, and endoglin. The urine sediments were analyzed for podocytes, identified by staining for podocin after culturing the urinary sediments for 24 hours. This analysis included all women who developed preeclampsia (n=15), gestational hypertension (n=15), and a subsample of women who remained normotensive throughout pregnancy (n=44), matched for maternal age and number of previous pregnancies to those who developed preeclampsia. At the second trimester collection, all women who developed preeclampsia had podocyturia, compared with none of those who remained normotensive or were diagnosed with gestational hypertension. Podocyturia in the second trimester had a significantly greater sensitivity and specificity for the subsequent diagnosis of preeclampsia than any single angiogenic marker or a combination thereof. Screening for podocyturia at the end of the second trimester may allow for accurate identification of pregnant women at risk for preeclampsia.

Preeclampsia as a risk factor for cardiovascular disease later in life: validation of a preeclampsia questionnaire

OBJECTIVE This study was undertaken to validate a self-administered questionnaire in verifying the diagnosis of preeclampsia, eclampsia, or toxemia in a group of women with a greater than 20-year history of preeclampsia. STUDY DESIGN Questionnaires were mailed to a random sample of 144 women who received a diagnosis of any of these 3 conditions and 158 women who had normotensive pregnancies at Mayo Clinic, Rochester, Minnesota, from 1960-1979. RESULTS A previous diagnosis of preeclampsia, eclampsia, or toxemia was verified with 80% sensitivity and 96% specificity. CONCLUSION Our validated questionnaire may be a useful research tool in identifying women with a previous history of preeclampsia. Women with a history of preeclampsia had a higher prevalence of future hypertension than those with a history of normotensive pregnancy.

Successful term pregnancy following MR-guided focused ultrasound treatment of uterine leiomyoma.

Objective:Term vaginal delivery after magnetic resonance-guided focused ultrasound therapy (MRgFU) for symptomatic uterine leiomyoma.Study design:A 38-year-old nulligravida underwent MRgFU treatment per study protocol for a solitary 9 × 10 × 10 cm uterine myoma and conceived 18 months following the procedure. She was counseled on the unknown implications of MRgFU during subsequent pregnancy. Myoma size increased significantly during gestation. At 39 weeks, she underwent indicated labor induction with vacuum-assisted vaginal delivery of a healthy male infant.Conclusion:In one pregnancy following MRgFU, there were no associated antepartum or intrapartum obstetrical complications.

Mass spectrometry as a novel method for detection of podocyturia in pre-eclampsia

BACKGROUND Podocyturia, i.e. urinary loss of viable podocytes, may serve as a diagnostic tool for pre-eclampsia and as a marker of active renal disease. The current method to detect podocyturia is technically complex, lengthy and requires a high level of expertise for interpretation. The aim of this study was to develop a new technique for the identification of urinary podocytes, based on the detection of podocyte-specific tryptic peptides by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), which will provide an operator-independent and highly reproducible method. METHODS AND RESULTS The diagnosis of pre-eclampsia was confirmed in the presence of hypertension (>140/90 mmHg) and proteinuria >0.3 g/24 h urine. The diagnosis of HELLP was confirmed based on the accepted clinical criteria of hemolysis, elevated liver enzymes and low platelet count. Random urine samples within 24 h prior to delivery were collected and centrifuged. One half of the sediment was cultured for 24 h to select for viable cells and then stained with a podocin antibody, followed by a secondary fluorescein isothiocyanate-labeled antibody to identify podocytes. The second half of the pellet was solubilized, digested and analyzed by LC-MS/MS using an internal standard. We have recruited 13 patients with pre-eclampsia and 6 patients with pre-eclampsia/HELLP syndrome. The presence of podocytes was confirmed in all patients by the podocyte culture method. In the respective samples, the presence of a podocin-specific tryptic peptide was confirmed with LC-MS/MS technology. CONCLUSION The LC-MS/MS method is a reliable technology for the identification of urinary podocytes, based on the presence of podocyte-specific proteins in the urine.

Comparison and validation of point of care lactate meters as a replacement for fetal pH measurement

OBJECTIVE To validate a point of care lactate device to replace fetal pH measurement. STUDY DESIGN AND METHODS Cord blood samples drawn immediately following delivery were tested on the Nova Lactate Plus and ARKRAY Lactate Pro, the Corometrics 220 pH System, and the Vitros chemistry analyzer (used as lactate reference). RESULTS Nova demonstrated a constant positive bias relative to the lactate reference method; while the Lactate Pro correlated well with the reference method up to 6 mmol/L. Receiver operating characteristic (ROC) curve analysis showed optimal sensitivity and specificity for predicting pH<7.20 at lactate values of 6.8 mmol/L for the Nova and 4.8 mmol/L for the Lactate Pro. CONCLUSION Using Lactate Pro the best cut-off for predicting pH< or =7.20 was 4.8 mM; which coincides with current clinical cut-offs. Thus any lactate device that correlates well with the laboratory reference method can be used with a clinical cut-off of 4.8 mmol/L.

Elevated expression of serine protease HtrA1 in preeclampsia and its role in trophoblast cell migration and invasion

OBJECTIVE Aberrant expression of developmentally regulated genes during placental development could affect fetal growth and contribute to preeclampsia. Expression of serine protease HtrA1 is developmentally regulated with the highest expression in decidua capsularis, compared with ectoplacental cone, and with the highest expression during later stages of pregnancy, compared with early stages. This study was designed to determine the expression of HtrA1 in placental tissues from control and preeclamptic pregnancies and to determine the effect of HtrA1 expression in trophoblast cell migration and invasion. STUDY DESIGN HtrA1 expression was assessed by immunohistochemistry in placentas from gestational age-matched preeclamptic and control pregnancies. HtrA1 expression in extravillous trophoblast cells, HTR-8/SVneo, was assessed by immunoblotting and immunofluorescence microscopy. Finally, the effect of ectopic expression of HtrA1 on cell migration and invasion was determined in HTR-8/SVneo cells. RESULTS Higher expression of HtrA1 was detected in placental tissues collected from patients with early-onset preeclampsia, compared with those from gestational age-matched control samples. Moreover, ectopic expression of HtrA1 significantly attenuates HTR-8/SVneo cell migration and invasion. CONCLUSION Higher expression of HtrA1 is associated with early-onset preeclampsia and may affect trophoblast cell migration and invasion.

Persistent Urinary Podocyte Loss following Preeclampsia May Reflect Subclinical Renal Injury

Objective Studies have shown that podocyturia, i.e., urinary loss of viable podocytes (glomerular epithelial cells), is associated with proteinuria in preeclampsia. We postulated that urinary podocyte loss may persist after preeclamptic pregnancies, thus resulting in renal injury. This may lead to future chronic renal injury. In addition, we compared the postpartum levels of the angiogenic factors, which previously have been associated with preeclampsia, between normotensive versus preeclamptic pregnancies. Study Design The diagnosis of preeclampsia was confirmed using standard clinical criteria. Random blood and urine samples were obtained within 24 hours prior to delivery and 5 to 8 weeks postpartum. Urine sediments were cultured for 24 hours to select for viable cells and staining for podocin was used to identify podocytes. Serum samples were analyzed for the levels of angiogenic markers using ELISA (enzyme-linked immunosorbent assay) methodology. Results At delivery, preeclamptic patients (n = 10) had significantly higher proteinuria (p = 0.006) and podocyturia (p<0.001) than normotensive pregnant patients (n = 18). Postpartum proteinuria was similar between these two groups (p = 0.37), while podocyturia was present in 3 of 10 women with preeclampsia and in none of the normotensive controls (p = 0.037). Angiogenic marker levels, including placental growth factor, soluble vascular endothelial growth factor receptor fms-like tyrosine kinase receptor-1 and endoglin, were not significantly different between women with preeclampsia and women with a normotensive pregnancy, either at delivery or postpartum. Conclusion Persistent urinary podocyte loss after preeclamptic pregnancies may constitute a marker of ongoing, subclinical renal injury.

Pharmacokinetics of methylene blue dye for lymphatic mapping in breast cancer-implications for use in pregnancy.

BACKGROUND although blue dye is routinely used for lymphatic mapping, it is not used for lymphatic mapping in pregnancy-associated breast cancer, because of concern of fetal risk. METHODS to investigate the safety of blue dye for lymphatic mapping in pregnant women, the pharmacokinetics of methylene blue dye were examined in 10 nonpregnant women, and the results were extrapolated to estimate maximal fetal exposure to the dye. RESULTS plasma and urine measurements indicated that the dye quickly distributed from the breast injection site to the circulation, with 32% of the total dose excreted in urine within 48 hours. Combined with existing data on organ distribution of methylene blue, the estimated maximal dose to the fetus is 0.25 mg (5% of the administered dose), likely further reduced by other physiologic factors related to pregnancy. CONCLUSIONS the analysis suggests that methylene blue dye can be used for lymphatic mapping in pregnancy-associated breast cancer with minimal fetal risk.