Darren S. Hoffmann

Chronic Tempol Prevents Hypertension, Proteinuria, and Poor Feto-Placental Outcomes in BPH/5 Mouse Model of Preeclampsia

Recently we described a mouse model, BPH/5, that spontaneously develops the hallmark clinical features of preeclampsia. BPH/5 exhibit impaired placentation before the onset of hypertension and proteinuria, supporting a causal role for the placenta in the pathogenesis of preeclampsia. Here we tested the hypothesis that an increase in reactive oxygen species (ROS) early in pregnancy results in placental abnormalities leading to the maternal symptoms of preeclampsia. We further hypothesized that chronic antioxidant therapy would ameliorate both feto-placental abnormalities and maternal symptoms. ROS levels measured by dihydroethidium revealed significant increases in oxidative stress in BPH/5 placentas at midgestation compared with C57 controls. This increase in ROS was correlated with reduced expression and activity of cytoplasmic superoxide dismutase in early and midgestation BPH/5 placentas. These abnormalities in placental oxidant factors occurred before the onset of maternal symptoms, suggesting a possible causal link between increased ROS and maternal and feto-placental pathology in this model. In support of this, chronic treatment of BPH/5 with the superoxide dismutase-mimetic Tempol throughout gestation significantly improved fetal growth and survival. Furthermore, Tempol ameliorated pregnancy-induced increases in blood pressure and proteinuria in BPH/5 mothers. We confirmed that Tempol radical was present in plasma, and it normalized ROS levels in all placental zones in BPH/5. These data for the first time demonstrate an important causative role for increased ROS in the placenta in the pathogenesis of preeclampsia in a model that spontaneously develops the disease. The results also strongly suggest the potential utility of antioxidant therapy in treating preeclampsia.

Severe Feto-Placental Abnormalities Precede the Onset of Hypertension and Proteinuria in a Mouse Model of Preeclampsia

Abstract Preeclampsia is a prevalent and potentially devastating disorder of pregnancy. Characterized by a sudden spike in blood pressure and urinary protein levels, it is associated with significant obstetric complications. BPH/5 is an inbred mouse model of preeclampsia with borderline hypertension before pregnancy. BPH/5 mice develop hypertension, proteinuria, and endothelial dysfunction during late gestation (after E14.5). We hypothesized that BPH/5 mice might exhibit early feto-placental abnormalities before the onset of maternal disease. All placental cell lineages were present in BPH/5 mice. However, the fetal and placental weights were reduced, with abnormalities in all the placental zones observed starting early in gestation (E9.5-E12.5). The fractional area occupied by the junctional zone was significantly reduced at all gestational timepoints. Markedly fewer CDKN1C-stained trophoblasts were seen invading the proximal decidual zone, and this was accompanied by reductions in Cdkn1c gene expression. Trophoblast giant cell morphology and cytokeratin staining were not altered, although the mRNA levels of several giant cell-specific markers were significantly downregulated. The labyrinth layer displayed decreased branching morphogenesis of endothelial cells, with electron microscopy evidence of attenuated trophoblast layers. The maternal decidual arteries showed increased wall-to-lumen ratios with persistence of actin-positive smooth muscle cells. These changes translated into dramatically increased vascular resistance in the uterine arteries, as measured by pulse-wave Doppler. Collectively, these results support the hypothesis that defects at the maternal-fetal interface are primary causal events in preeclampsia, and further suggest the BPH/5 model is important for investigations of the underlying pathogenic mechanisms in preeclampsia.

Adenoviral Delivery of VEGF121 Early in Pregnancy Prevents Spontaneous Development of Preeclampsia in BPH/5 Mice

An imbalance in circulating proangiogenic and antiangiogenic factors is postulated to play a causal role in preeclampsia (PE). We have described an inbred mouse strain, BPH/5, which spontaneously develops a PE-like syndrome including late-gestational hypertension, proteinuria, and poor feto-placental outcomes. Here we tested the hypothesis that an angiogenic imbalance during pregnancy in BPH/5 mice leads to the development of PE-like phenotypes in this model. Similar to clinical findings, plasma from pregnant BPH/5 showed reduced levels of free vascular endothelial growth factor (VEGF) and placental growth factor (PGF) compared to C57BL/6 controls. This was paralleled by a marked decrease in VEGF protein and Pgf mRNA in BPH/5 placentae. Surprisingly, antagonism by the soluble form of the FLT1 receptor (sFLT1) did not appear to be the cause of this reduction, as sFLT1 levels were unchanged or even reduced in BPH/5 compared to controls. Adenoviral-mediated delivery of VEGF121 (Ad-VEGF) via tail vein at embryonic day 7.5 normalized both the plasma-free VEGF levels in BPH/5 and restored the in vitro angiogenic capacity of serum from these mice. Ad-VEGF also reduced the incidence of fetal resorptions and prevented the late-gestational spike in blood pressure and proteinuria observed in BPH/5. These data underscore the importance of dysregulation of angiogenic factors in the pathogenesis of PE and suggest the potential utility of early proangiogenic therapies in treating this disease.

Dissection and Dissection-Associated Required Experiences Improve Student Performance in Gross Anatomy: Differences among Quartiles.

To promote student learning, educational strategies should provide multiple levels of engagement with the subject matter. This study investigated examination data from five first year medical gross anatomy class cohorts (692 students) to determine if enhanced student performance was correlated with learning through dissection in a course that used a rotating dissection schedule coupled with peer teaching and other associated experiences. When students performed two of five weekly dissections for a given unit, their average scores on both laboratory and written examinations tended to increase as compared to when they had completed only one week of dissection (P < 0.01). However, these performance gains differed across the class strata and were related to the amount of dissection completed. Students in the upper quartile (UQS) of the class benefited when they had dissected once (92.8%) or twice (92.4%), and these scores were significantly higher than those attained when learning from peers (90.3%, P < 0.01). Students in the lower quartile (LQS) benefited most from the dissection experiences, where practical examination performance was better (77.8% and 80.5%) than when these students learned material from their peers (73.7%, P < 0.01). Although UQS benefited from dissection, LQS benefited to a greater extent in both the practical and written examinations with dissection. Although limited, these data suggest that dissection, coupled with associated educational activities, is an effective pedagogical strategy for learning. Further investigation is required to evaluate the concomitant benefits of peer teaching that are associated with the dissection experience. Anat Sci Educ 9: 238–246.

Erratum: Application of flipped classroom pedagogy to the human gross anatomy laboratory: Student preferences and learning outcomes

In the published article ASE.1755, Table 4 contained an error in the values for the pre-flip sub-cohorts of examinations 1, 2 and 3. The corrected Table 4 is now presented below. The authors explain that in the original construction of the table’s 3 3 3 matrix of pre-flip subcohort means over the 3 examinations, the axes were inverted resulting in a shuffling of sub-cohort means. However, all cohort means and statistical analyses were correct. The corrected Table 4 contains the correct examination means for the subcohorts. Because all interpretation and conclusions were based on cohort means, this correction does not affect the results or conclusions of the paper.

Teaching Your Research: A Workshop to Teach Curriculum Design to Graduate Students and Post-doctoral Fellows

Graduate students and post-doctoral fellows are typically underprepared for the teaching roles they will take on when they assume faculty positions. While students are often undertrained in the complex skills of teaching, they are highly adept in their research areas, making them uniquely qualified to teach the science underlying their research. We hypothesized a sequential curriculum design workshop focused on designing a course based on their research would increase graduate students’ and post-doctoral fellows’ skills and confidence in teaching. To test this hypothesis, we designed a workshop series (nine weekly one-hour sessions) that would progressively lead senior Ph.D. candidates and post-doctoral fellows through the basics of curriculum design and culminate in the assembly of a full course syllabus using a wide range of learned curriculum design skills. Junior research-oriented departmental faculty were recruited to participate as discussion facilitators. Of the 31 students who participated in three separate cohorts, 22 completed the workshop and submitted final projects of a full course syllabus, complete with learning objectives, instructional plans, course schedule, and assessment approaches. Syllabi were evaluated for quality by two independent reviewers. Participants retrospectively self-assessed their skill level in each of eight key course objectives, and significant changes in all parameters were reported. They also completed pre- and post-course surveys to assess student attitudes about teaching. Participants reported significantly increased comfort with curriculum design and confidence in their ability to teach. In summary, this workshop represents a minimally burdensome and easily implementable workshop approach to providing teaching skills preparation for research-focused graduate students and post-doctoral fellows who typically receive little to no formal teaching training.