Findings correlate with clinical observations of more fetal abnormalities and other Zika-related health problems in late versus early pregnancy

Tampa, FL (Feb. 2, 2021) — A preclinical study by a University of South Florida Health (USF Health) Morsani College of Medicine research team has discovered a new mechanism for how Zika virus passes from mothers to their children during pregnancy – a process known as vertical transmission.

The researchers showed, for the first time, that specialized cells lining the uterus (maternal decidual cells) act as reservoirs for trimester-dependent transmission of the virus through the placenta – accounting for both the fetus’s greater susceptibility to first-trimester Zika infection and for the more serious congenital defects observed in early versus late pregnancy. They also report that the agent tizoxanide inhibits ZIKA virus in maternal decidual cells grown in the lab, offering promise for preventing perinatal transmission that can cause devastating malformations and brain damage in developing fetuses and infants.

The findings appeared Dec. 1, 2020 in the Journal of Immunology.

The study was led by co-principal investigators Ozlem Guzeloglu-Kayisli, PhD, a USF Health associate professor of obstetrics and gynecology, and Charles J. Lockwood, MD, USF Health senior vice president, dean of the Morsani College of Medicine, and a professor of obstetrics and gynecology specializing in maternal-fetal medicine.

“If we can better understand Zika virus vertical transmission and successfully block infection in maternal (decidual) cells early in the pregnancy, the virus will not pass through the placenta to reach the fetus and it is less likely to cause severe abnormalities,” said Dr. Guzeloglu-Kayisli, the paper’s lead author.

Ozlem Guzeloglu-Kayisli, PhD, USF Health associate professor of obstetrics and gynecology, was the paper’s lead author.| Photo by Allison Long, USF Health Communications and Marketing

Charles J. Lockwood, MD, dean of the USF Health Morsani College of Medicine and a professor of obstetrics and gynecology specializing in maternal-fetal medicine, was a co-principal investigator for the Zika study along with Dr. Guzeloglu-Kayisli. | Photo by Freddie Coleman, USF Health Communications and Marketing

The widespread global alarm caused by the spread of mosquito-borne Zika virus throughout the Americas in 2015-2016 dissipated after the virus all but disappeared in 2017. Yet, resurgence remains possible in areas where the Aedes aegypti mosquito is prevalent, and there is no treatment or vaccine available for Zika virus infection.

While most Zika-infected adults show no symptoms, the virus can cause minor flu-like symptoms, and in rare cases has been associated with Guillain-Barre syndrome. However, Zika poses the most concern for pregnant women, because up to one in 10 newborns of affected mothers suffer Zika-associated birth defects, including smaller than normal head size (microcephaly) that can lead to developmental disabilities and other health problems. Zika has also been linked to pregnancy complications, including preterm birth, preeclampsia and miscarriage. Moreover, timing appears important. Mothers infected in the first trimester are much more likely to have babies with severe Zika birth defects than mothers infected in the third semester.

The placenta, the organ supplying maternal oxygen and nutrients to the growing fetus, has ways to prevent most pathogens, including viruses, from crossing its protective maternal-fetal barrier. A subtype of fetally-derived placental cells known as syncytiotrophoblasts, in direct contact with maternal blood, are assumed to be the site where the Zika virus enters the placenta, leading to potential fetal infection. However, Dr. Ozlem Guzeloglu-Kayisli said, these particular trophoblasts resist Zika virus attachment and replication.

Above and close-up below: A model for mother-to-fetus transmission of Zika virus (green particles) through maternal decidual cell-mediated infection of villi attaching the placenta to the endometrium (uterine lining). | Images courtesy of USF Health first appeared in the Journal of Immunology: doi: 10.4049/jimmunol.2000713

To learn more about how Zika gets through the placental wall, the USF Health team began by investigating the cellular and molecular mediators of Zika virus replication. Among their key findings, the researchers:

–  Showed that specialized uterine cells from both pregnant and nonpregnant women were highly infectable by Zika virus. These immunologically active decidual cells, which line the uterus in preparation for and during pregnancy, form the maternal part of the placenta closest to the fetus.

–  Identified a more than 10,000-fold higher expression of the Zika virus attachment-entry receptor in the maternal decidual cells than in the fetal trophoblasts. Once inside the maternal cells, the Zika virus (an RNA virus) hijacks the cellular machinery to make proteins needed to copy its genetic material and churn out new viral particles. The proliferation of viral particles released from the maternal cells are then transmitted through branch-like vascular projections (villi) on the placenta’s surface layer where they can infect fetal trophoblast cells otherwise resistant to Zika virus.

–  Found that the efficiency of viral replication was significantly greater in first-trimester decidual cells than in those from term pregnancies.

–  Concluded that maternal (decidual) cells likely serve as the source for initial Zika virus infection and enhance subsequent transmission through the placenta to the fetus. “Moreover, trimester-dependent responses of decidual cells to Zika virus help to explain why pregnant women are susceptible to Zika infection and why the subsequent effects are more detrimental in the first trimester than in late pregnancy,” the study authors wrote.

–  Demonstrated that tizoxanide, the active metabolite of FDA-approved antiparasitic drug nitazoxanide, effectively impeded Zika virus infection in both maternal decidual cells and fetal trophoblast cells. The drug has been shown preclinically to inhibit a broad range of flu-like viruses and is being tested clinically against coronavirus. The finding warrants further testing of tizoxanide to block perinatal transmission of Zika virus and thereby protect the fetus from harmful outcomes, the researchers conclude.

The team’s work was supported in part by a Zika Research Initiative grant from the Florida Department of Health.

USF Health researchers applied CRISPR technology to study the very large human non-protein coding gene expressed only in placenta, stem cells and certain cancers

TAMPA, Fla (March 16, 2020) — The placenta, an organ which attaches to the lining of the uterus during pregnancy, supplies maternal oxygen and nutrients to the growing fetus. Abnormal formation and growth of the placenta is considered an underlying cause of various pregnancy complications such as miscarriages, stillbirth, preeclampsia and fetal growth restriction. Yet, much remains to be learned about molecular mechanisms regulating development of this blood-vessel rich organ so vital to the health of a pregnant woman and her developing fetus.

Hana Totary-Jain, PhD, an associate professor of molecular pharmacology and physiology in the USF Health Morsani College of Medicine, was senior author of the study published in Scientific Reports.

University of South Florida Health (USF Health) Morsani College of Medicine researchers recently discovered how a very large human non-protein coding gene regulates epithelial-to-mesenchymal transition (EMT) – a process that contributes to placental development during early pregnancy, but can also promote cancer progression.

During the first trimester, fetal-derived placental cells known as trophoblasts invade the maternal uterine lining and modify its blood vessels to allow oxygenated blood to flow from the mother to fetus. However, trophoblast invasion requires tight regulation of EMT. If inadequate, trophoblast invasion is too shallow to adequately remodel the maternal blood vessels, and adverse pregnancy outcomes can occur. Conversely, excess EMT can cause exaggerated trophoblast invasion through the uterine wall leading to placenta accreta, a condition that can cause hemorrhage and often requires hysterectomy at delivery.

The USF Health researchers used a powerful genome editing technology called CRISPR (shorthand for “CRISPR-dCas9) to activate all of the chromosome 19 microRNA cluster (known as C19MC), so they could study the gene’s function in early pregnancy. C19MC — one of the largest microRNA gene clusters in the human genome — is normally turned off but becomes expressed only in the placenta, embryonic stem cells and certain cancers.

Dr. Totary-Jain discusses the molecular aspects of placenta development and pregnancy complications with research collaborator Umit Kayisli, PhD, a professor of obstetrics and gynecology at USF Health.

In their cell model study, published Feb. 20 in Scientific Reports, a Nature research journal, the USF Health team showed that robust activation of C19MC inhibited EMT gene expression, which has been shown to reduce trophoblast invasion.

But when trophoblast-like cells were exposed to hypoxia – a lack of oxygen similar to that occurring in early placental development — C19MC expression was significantly reduced, the researchers found. The loss of C19MC function causes differentiation of trophoblasts from stem-like epithelial cells into mesenchymal-like cells that can migrate and invade much like metastatic tumors. This EMT process helps explain trophoblast invasion and early placental formation.

“We were the first to use CRISPR to efficiently activate the entire gene, not just a few regions of this huge gene, in human cell lines,” said the paper’s senior author Hana Totary-Jain, PhD, an associate professor in the Department of Molecular Pharmacology and Physiology, USF Health Morsani College of Medicine. “Our study indicates C19MC plays a key role in regulating many genes important in early implantation and placental development and function. The regulation of these genes is critical for proper fetal growth.”

Above: Chromosome 19 microRNA cluster (stained purple) expressed in first-trimester placenta.  Below: In preparation for pregnancy, fetal trophoblast cells (brown) from which the placenta arises invade maternal decidual cells (pink) in the uterus lining. | Images courtesy of Hana Totary-Jain, originally published in Scientific Reports: doi.org/10.1038/s41598-020-59812-8

“You need EMT, but at some point the process needs to cease to prevent adverse pregnancy outcomes,” Dr. Totary-Jain said. “You really need a balance between not enough invasion and too much invasion, and C19MC is important in maintaining that balance.”

Dr. Totary-Jain and others in her department collaborated with colleagues in the medical college’s Department of Obstetrics and Gynecology on the project.

“The USF Health study offers new insight into how trophoblasts interact with the maternal uterine environment to become more invasive or less invasive in the formation of the placenta,” said coauthor Umit Kayisli, PhD, a USF Health professor of Obstetrics and Gynecology. “More research on microRNA expression and how it inhibits EMT may help us better understand the causes and potential prevention of preeclampsia and fetal growth restriction, which account for 5-to-10 percent of all pregnancy complications as well as spontaneous preterm births.”

Investigating the effects of altered C19MC expression on cell differentiation and trophoblast invasion has implications not only for a better understanding of normal and abnormal placental development, but also for cancer and stem cell research, Dr. Totary-Jain added.

Dr. Totary-Jain and Dr. Kayisli

Photos by Freddie Coleman, USF Health Communications and Marketing

The University of South Florida-led study created a rigorous mathematical model to simulate maternal and newborn outcomes, comparing elective induction to expectant management

TAMPA, Fla. (April 25, 2018) – It’s better to induce labor than to watch and wait.  That’s the main result of a new study published in PLOS ONE.

Researchers at the University of South Florida Morsani College of Medicine found that first-time healthy mothers electively induced at 39 weeks of pregnancy are at lower risk of cesarean delivery and other serious complications compared to those expectantly managed and induced at 41 weeks if undelivered by then.

Photo by Sandra C. Roa | University of South Florida Communications and Marketing

Obstetricians generally recommend inducing (artificially stimulating) labor and delivery after 41 weeks since continued pregnancy after this point is associated with higher chances of stillbirth and risks to the mother. However, uncertainty exists about best timing of deliveries when the fetus is between 39 and 41 weeks. The USF-led study presents compelling evidence that electively inducing labor at 39 weeks results in less risk, not more, to mothers and their newborn infants than expectant management, or watchful waiting, in the same population.

Elective induction was associated with reduced rates of cesarean deliveries and maternal complications including preeclampsia, fewer stillbirths and newborn deaths, and lower rates of newborn complications such as birth injuries, respiratory distress and shoulder dystocia (infant’s shoulder becomes lodged behind the mother’s pubic bone).

“Safely preventing primary cesarean deliveries, stillbirths and reducing other perinatal complications are of the greatest concern,” said the study’s principal investigator Charles J. Lockwood, MD, senior vice president for USF Health and dean of the Morsani College of Medicine. “Sometimes clinicians do something because that is the way it’s always been done. These findings demonstrate the importance of strong evidence-based research in informing and shaping standards of care.”

“When I was in residency training, it was drilled into us that elective induction of labor increased C-section deliveries.  But, actually we found the opposite” said lead author Rachel Sinkey, MD.  Dr. Sinkey conducted the research when she was a maternal-fetal medicine fellow at USF Health and is now an assistant professor of obstetrics and gynecology in the Division of Maternal-Fetal Medicine, University of Alabama at Birmingham.

The USF researchers created a rigorous mathematical model, using data from the NIH’s Safe Labor Consortium supplemented by review of the latest medical literature. A theoretical cohort of 100,000 patients was used to simulate key pregnancy outcomes for two groups: first-time mothers with low-risk pregnancies who elected to have labor induced at 39 weeks and those choosing expectant management with induction of labor only if medically indicated or if their pregnancies extended beyond 41 weeks.

Compared to elective induction of labor at 39 weeks, waiting to induce labor at 41 weeks resulted in increased:

• C-section rates (35.9 vs. 13.9 percent). Even when the cervix was unfavorable in position or dilation, C-sections were more frequent with expectant management.
• Maternal complications (21.2 vs. 16.5 percent)
• Stillbirths (0.13 vs. 0 percent)
• Newborn deaths (0.25 vs. 0.12 percent)
• Severe neonatal complications (12.1 vs. 9.4 percent)

The USF findings were recently corroborated by results of the National Institutes of Health-supported ARRIVE trial of induction versus expectant management.  That large-scale, randomized controlled trial also found that induction of labor at 39 weeks in low-risk pregnant women resulted in a lower frequency of cesarean deliveries and preeclampsia.

The USF findings are supported by biologically plausible explanations. Both inadequate delivery of essential nutrients and oxygen to the fetus, known as placental insufficiency, and increasing fetal growth are associated with advanced pregnancies and may explain why elective induction of labor at 39 weeks reduces the risk of adverse pregnancy outcomes, Dr. Sinkey said.

More study is needed to address health care system logistics and costs associated with routine elective induction of labor at 39 weeks. Spontaneous labor without medical intervention remains critically important to many women, Dr. Sinkey said, however, induction of labor should be presented to patients as an acceptable option.

“We acknowledge that not all women nor their providers desire elective inductions and we recommend that the patient should be final arbiter of the timing and mode of delivery after adequate counseling and informed consent,” the study authors conclude.

The common sleep disorder was also associated with uncommon medical conditions leading to pregnancy-related deaths, large-scale analysis by the University of South Florida indicated

Tampa, FL (May 1, 2014) — Pregnant women with obstructive sleep apnea are more than five times as likely to die in the hospital than those without the sleep disorder, a comprehensive national study by University of South Florida researchers found.

Among delivery-related hospital discharges, sleep apnea was also associated with an increase in severe medical conditions that are top causes of maternal death, including preeclampsia, eclampsia, an enlarged heart and pulmonary blood clots, reported the study published online today in the journal SLEEP.

Dr. Judette Louis, assistant professor of obstetrics and gynecology at the USF Health Morsani College of Medicine, led the large-scale national study appearing in the journal SLEEP. She specializes in maternal-fetal medicine, working out of Tampa General Hospital.

Sleep apnea causes repeated awakenings and pauses in breathing during the night.  Previous smaller studies have found that the condition increases the risk for poor pregnancy outcomes, including preeclampsia (high blood pressure in pregnancy associated with loss of protein in the urine), restricted growth of the fetus, preterm delivery and gestational diabetes.  Obesity appears to contribute to the adverse effects.

However, the USF study provided the first large-scale U.S. analysis of the association between sleep apnea and maternal deaths.

“The astounding association with maternal death was surprising,” said lead author Judette Louis, MD, MPH, assistant professor of obstetrics and gynecology at the USF Health Morsani College of Medicine who works out of Tampa General Hospital.  “I did not expect to find such a difference in mortality between pregnant women who had sleep apnea and those who did not, especially when we controlled for obesity and other complicating factors.

While more study is needed, the increased likelihood of death for those with sleep apnea may be explained in part by the physiological demands of pregnancy, she said. “Underlying damage or chronic disease caused by sleep apnea may be exacerbated by the stresses of pregnancy.”

Maternal death rates have increased slightly in recent years, and obesity is one suspected reason.

“Our study indicates that sleep apnea may also play a role, whether a woman is obese or not,” said Dr. Louis, who holds a joint appointment in the USF College of Public Health’s Department of Community and Family Health. “It’s important for obstetricians and primary care practitioners to identify sleep apnea in younger women of reproductive age, convey its risk, and treat the condition before pregnancy.”

The researchers drew upon a nationally representative sample of 55 million maternal-related hospital discharges from 1998 to 2009 – women who were pregnant or gave birth while in the hospital.  They identified those with sleep apnea diagnoses and examined the links between this sleep-disordered breathing and poor pregnancy health outcomes, including in-hospital deaths.

Jamillet Flores, 34, diagnosed with sleep apnea during pregnancy, wears a CPAP device every night to help keep her upper airways open and reduce symptoms such as snoring and daytime drowsiness. While she did not experience pregancy-related complications from the sleep disorder, Flores only found out about the condition when it was diagnosed during an unrelated treatment at the hospital. “Sleep apnea is largely underdiagnosed in reproductive-age women,” Dr. Louis said.

Flores with her newborn son in the neonatal intensive care unit at Tampa General.

Among the retrospective study’s findings:

–          Women with sleep apnea during pregnancy were more likely to experience serious medical conditions and pregnancy-related complications than women without sleep apnea diagnoses.

–          The strongest associations were with the following medical conditions:  cardiomyopathy (an enlarged heart), heart failure and pulmonary edema (fluid build-up in the lungs).

–          Among pregnancy-related complications, sleep apnea was associated with a greater likelihood of eclampsia and preeclampsia as well as gestational diabetes and gestational high blood pressure, even after controlling for obesity.

–          Even after adjusting for potentially life-threatening cardiovascular and metabolic conditions, women with sleep apnea were five times more likely to die before discharge from the hospital than their counterparts without sleep apnea.

–          The increase in the rate of sleep apnea among pregnancy-related discharges over the study period coincided with a rise in obesity rates.

–          With the exception of cesarean delivery, gestational hypertension and stillbirth, the likelihood of potentially life-threatening illnesses and maternal death were higher for women with sleep apnea – irrespective of obesity.

–          The presence of obesity appeared to intensify the effects of risks of cardiovascular disease in pregnant women with sleep apnea.

Article citation:
Louis JM, Mogos MF, Salemi JL, Redline S, Salihu HM. “Obstructive sleep apnea and severe maternal-infant morbidity/mortality in the United States, 1998-2009.” SLEEP, 2014;37(5):843-849.

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Photos by Eric Younghans, USF Health Communications

Media contact:
Anne DeLotto Baier, USF Health Communications
abaier@health.usf.edu or (813) 974-3303