Bio

Clinical Focus


  • Maternal and Fetal Medicine

Academic Appointments


Administrative Appointments


  • Director of Perinatal Biology, Stanford University School of Medicine (2014 - Present)

Professional Education


  • Board Certification: Maternal and Fetal Medicine, American Board of Obstetrics and Gynecology (2009)
  • Board Certification: Obstetrics and Gynecology, American Board of Obstetrics and Gynecology (2005)
  • Fellowship:UCSF (2003) CA
  • Residency:UCSF (2000) CA
  • Medical Education:University of Rochester School of Medicine (1996) NY
  • University of Rochester School of Medicine (1994)

Teaching

Stanford Advisees


Publications

All Publications


  • Differential expression of human placental PAPP-A2 over gestation and in preeclampsia PLACENTA Kramer, A. W., Lamale-Smith, L. M., Winn, V. D. 2016; 37: 19-25

    Abstract

    Pregnancy Associated Plasma Protein A2 (PAPP-A2) is a pregnancy related insulin-like growth factor binding protein-5 (IGFBP-5) protease, known to be elevated in preeclampsia. As the insulin-like growth factors are important in human implantation and placentation, we sought to determine the expression pattern of PAPP-A2 over human gestation in normal and preeclamptic pregnancies to evaluate its role in placental development and the pathogenesis of preeclampsia.Placental basal plate and chorionic villi samples, maternal and fetal cord blood sera were obtained from preeclamptic and control pregnancies. Formalin-fixed tissue sections from across gestation were stained for cytokeratin-7, HLA-G, and PAPP-A2. PAPP-A2 immunoblot analysis was also performed on protein lysates and sera.PAPP-A2 expression is predominately expressed by differentiated trophoblasts and fetal endothelium. Chorionic villi show strong expression in the first trimester, followed by a progressive decrease in the second trimester, which returns in the third trimester. PAPP-A2 expression is not impacted by labor. PAPP-A2 is increased in the basal plate, chorionic villi and maternal sera in preeclampsia compared to controls, but is not detectable in cord blood.PAPP-A2 is differentially expressed in different trophoblast populations and shows strong down regulation in the mid second trimester in chorionic villous samples. Both maternal sera and placental tissue from pregnancies complicated by preeclampsia show increased levels of PAPP-A2. PAPP-A2 levels are not altered by labor. Additionally, PAPP-A2 cannot be detected in cord blood demonstrating that the alterations in maternal and placental PAPP-A2 are not recapitulated in the fetal circulation.

    View details for DOI 10.1016/j.placenta.2015.11.004

    View details for Web of Science ID 000369194900004

    View details for PubMedID 26748159

  • Hepatitis C Virus Sensing by Human Trophoblasts Induces Innate Immune Responses and Recruitment of Maternal NK Cells: Potential Implications for Limiting Vertical Transmission JOURNAL OF IMMUNOLOGY Giugliano, S., Petroff, M. G., Warren, B. D., Jasti, S., Linscheid, C., Ward, A., Kramer, A., Dobrinskikh, E., Sheiko, M. A., Gale, M., Golden-Mason, L., Winn, V. D., Rosen, H. R. 2015; 195 (8): 3737-3747

    Abstract

    Hepatitis C virus (HCV) is the world's most common blood-borne viral infection for which there is no vaccine. The rates of vertical transmission range between 3 and 6% with odds 90% higher in the presence of HIV coinfection. Prevention of vertical transmission is not possible because of lack of an approved therapy for use in pregnancy or an effective vaccine. Recently, HCV has been identified as an independent risk factor for preterm delivery, perinatal mortality, and other complications. In this study, we characterized the immune responses that contribute to the control of viral infection at the maternal-fetal interface (MFI) in the early gestational stages. In this study, we show that primary human trophoblast cells and an extravillous trophoblast cell line (HTR8), from first and second trimester of pregnancy, express receptors relevant for HCV binding/entry and are permissive for HCV uptake. We found that HCV-RNA sensing by human trophoblast cells induces robust upregulation of type I/III IFNs and secretion of multiple chemokines that elicit recruitment and activation of decidual NK cells. Furthermore, we observed that HCV-RNA transfection induces a proapoptotic response within HTR8 that could affect the morphology of the placenta. To our knowledge, for the first time, we demonstrate that HCV-RNA sensing by human trophoblast cells elicits a strong antiviral response that alters the recruitment and activation of innate immune cells at the MFI. This work provides a paradigm shift in our understanding of HCV-specific immunity at the MFI as well as novel insights into mechanisms that limit vertical transmission but may paradoxically lead to virus-related pregnancy complications.

    View details for DOI 10.4049/jimmunol.1500409

    View details for Web of Science ID 000362968100028

    View details for PubMedID 26342030

  • Baseline placental growth factor levels for the prediction of benefit from early aspirin prophylaxis for preeclampsia prevention PREGNANCY HYPERTENSION-AN INTERNATIONAL JOURNAL OF WOMENS CARDIOVASCULAR HEALTH Moore, G. S., Allshouse, A. A., Winn, V. D., Galan, H. L., Heyborne, K. D. 2015; 5 (4): 280-286
  • A Hertzian contact mechanics based formulation to improve ultrasound elastography assessment of uterine cervical tissue stiffness JOURNAL OF BIOMECHANICS Briggs, B. N., Stender, M. E., Muljadi, P. M., Donnelly, M. A., Winn, V. D., Ferguson, V. L. 2015; 48 (9): 1524-1532

    Abstract

    Clinical practice requires improved techniques to assess human cervical tissue properties, especially at the internal os, or orifice, of the uterine cervix. Ultrasound elastography (UE) holds promise for non-invasively monitoring cervical stiffness throughout pregnancy. However, this technique provides qualitative strain images that cannot be linked to a material property (e.g., Young's modulus) without knowledge of the contact pressure under a rounded transvaginal transducer probe and correction for the resulting non-uniform strain dissipation. One technique to standardize elastogram images incorporates a material of known properties and uses one-dimensional, uniaxial Hooke's law to calculate Young's modulus within the compressed material half-space. However, this method does not account for strain dissipation and the strains that evolve in three-dimensional space. We demonstrate that an analytical approach based on 3D Hertzian contact mechanics provides a reasonable first approximation to correct for UE strain dissipation underneath a round transvaginal transducer probe and thus improves UE-derived estimates of tissue modulus. We validate the proposed analytical solution and evaluate sources of error using a finite element model. As compared to 1D uniaxial Hooke's law, the Hertzian contact-based solution yields significantly improved Young's modulus predictions in three homogeneous gelatin tissue phantoms possessing different moduli. We also demonstrate the feasibility of using this technique to image human cervical tissue, where UE-derived moduli estimations for the uterine cervix anterior lip agreed well with published, experimentally obtained values. Overall, UE with an attached reference standard and a Hertzian contact-based correction holds promise for improving quantitative estimates of cervical tissue modulus.

    View details for DOI 10.1016/j.jbiomech.2015.03.032

    View details for Web of Science ID 000357147000003

    View details for PubMedID 26003483