Thursday, August 18, 2016

Zika virus and the adult

Hongda Li, Laura Saucedo-Cuevas, Jose A. Regla-Nava, Guoliang Chai, Nicholas Sheets, William Tang, Alexey V. Terskikh, Sujan Shresta.  Zika virus infects neural progenitors in the adult mouse brain and alters proliferation.  Cell Stem Cell.  Published online: August 18, 2016.

Highlights

•Zika virus (ZIKV) can infect neural progenitors in the adult mouse brain
•ZIKV-infected adult NPCs show evidence of cell death
•Cell proliferation is also impacted in ZIKV-infected adult NPC populations

Summary

Zika virus (ZIKV)-related neuropathology is an important global health concern. Several studies have shown that ZIKV can infect neural stem cells in the developing brain, but infection in the adult brain has not been examined. Two areas in the adult mouse brain contain neural stem cells: the subventricular zone of the anterior forebrain and the subgranular zone of the hippocampus. Here, using 6-week-old mice triply deficient in interferon regulatory factor (IRF) as a model, we show that blood-borne ZIKV administration can lead to pronounced evidence of ZIKV infection in these adult neural stem cells, leading to cell death and reduced proliferation. Our data therefore suggest that adult as well as fetal neural stem cells are vulnerable to ZIKV neuropathology. Thus, although ZIKV is considered a transient infection in adult humans without marked long-term effects, there may in fact be consequences of exposure in the adult brain.
__________________________________________________________________________

Zika infection could put adults at risk of dementia and other neurological diseases and is likely even more dangerous than first thought, researchers at The Rockefeller University and La Jolla Institute for Allergy and Immunology report.

Based on a mouse study, they believe the virus could get into almost anyone’s brain—not just those of developing fetuses.

“Zika can clearly enter the brain of adults and can wreak havoc,” says Sujan Shresta, PhD, a professor at La Jolla.

Certain adult brain cells may be vulnerable to infection, including neural progenitor cells, also known as the stem cells of the brain.

Zika infection could put adults at risk of dementia and other neurological diseases and is likely even more dangerous than first thought, researchers at The Rockefeller University and La Jolla Institute for Allergy and Immunology report.

Based on a mouse study, they believe the virus could get into almost anyone’s brain—not just those of developing fetuses.

“Zika can clearly enter the brain of adults and can wreak havoc,” says Sujan Shresta, PhD, a professor at La Jolla.

Certain adult brain cells may be vulnerable to infection, including neural progenitor cells, also known as the stem cells of the brain.

The virus has already been associated with an increase in microcephaly in infants born to infected mothers. It can also cause , as well as shown to cause Guillain-Barre Syndrome, a rare illness in which the immune system attacks parts of the nervous system resulting in muscle weakness or even paralysis. 

Since that syndrome usually develops after the infection has cleared, Shresta says, “We propose that infection of adult neural progenitor cells could be the mechanism behind this," she added. 

Using mice, the researchers have shown that the virus was able to get into pockets of the rodents’ brains where these progenitor cells are located. Those are the subventricular zone of the anterior forebrain and the subgranular zone of the hippocampus, both vital for learning and memory.

According to Joseph Gleeson, MD, head of the Laboratory of Pediatric Brain Disease and an adjunct professor at The Rockefeller University in New York City, in a mouse model engineered by Shresta “It was very clear that the virus wasn’t affecting the whole brain evenly, like people are seeing in the fetus.” He added “In the adult, it’s only these two populations that are very specific to the stem cells that are affected by the virus,” cells that are “somehow very susceptible to the infection.”

The infection correlated with evidence of cell death and reduced generation of new neurons in these regions, which could set the stage for cognitive decline, depression, Alzheimer’s, or other neuropathological ailments.

The team added that some people may mount an effective immune response and halt the virus, but others, particularly those with weakened immune systems, may not. –

http://www.hcplive.com/medical-news/zika-more-dangerous-than-thought-brain-damage-risk-seen-in-all-infections?utm_source=Informz&utm_medium=HCPLive&utm_campaign=Trending_News_8-18-16#sthash.k6Xqpq9k.dpuf

2 comments:

  1. Researchers from the World Federation of Neurology's Work Group on Zika have reported the first confirmed case of a new Zika-associated neurological complication in adults.
    The case, described in a paper published in the Journal of Neurological Sciences, occurred to a 62-year-old Honduran male patient who had traveled to Venezuela. The patient presented acute sensory polyneuropathy during the active phase of his ZIka infection.

    "Our patient is the first confirmed Zika infection case report associated with an acute sensory polyneuropathy which began during the acute infectious phase," said Professor Marco T. Medina, Dean of the Faculty of Medical Sciences at the Universidad Nacional Autonoma de Honduras, in a press release. "This suggests a probable direct viral inflammatory process affecting sensory nerves, but an autoimmune etiology cannot be definitely excluded."

    Sensory polyneuropathy or peripheral neuropathy is a condition that occurs as a result of nerve damage in the peripheral nervous system, which is responsible of transmitting information between the central nervous system and the rest of the body.

    Patients with sensory polyneuropathy may experience gradual onset of numbness, prickling or tingling in the feet and hands; sharp, jabbing, throbbing, freezing or burning pain; extreme sensitivity to touch, lack of coordination and falling; muscle weakness or paralysis if motor nerves are affected.

    Additional symptoms may present if the autonomic nerves are also damaged. These symptoms include heat intolerance and altered sweating; bowel, bladder and digestive problems; changes in blood pressure, causing dizziness and lightheadedness.

    Zika virus is known to cause microcephaly with brain malformations in infants. There are also high occurrences of outbreaks of GuGuillain-Barré Syndrome (GBS) associated with Zika virus infections. Other neurological conditions linked to Zika infection include meningoencephalitis or acute myelitis.

    "Zika virus infection has become a new emergent neuropathological agent with several neurological complications," said lead author Dr. John England, a Professor and Chair of Neurology at LSU Health New Orleans School of Medicine and Chair of the Work Group of Zika, in a statement.

    http://www.natureworldnews.com/articles/27575/20160827/zika-update-new-zika-associated-neurological-disease-in-adults-confirmed.htm

    Marco T. Medina, John D. England, Ivette Lorenzana, Marco Medina-Montoya, Diego Alvarado, Mario De Bastos, Santiago Fontiveros, Manuel Sierra, Francis Contreras. Zika virus associated with sensory polyneuropathy. Journal of the Neurological Sciences. In press.

    Zika virus infection has become a new emergent neuropathological agent with several neurological complications. Cao-Lormeau et al. reported an outbreak of Guillain-Barré Syndrome (GBS) associated with Zika virus infection in French Polynesia. A syndrome associated with congenital Zika virus infection (mainly microcephaly with brain malformations) was reported initially in Brazil and how now been confirmed elsewhere. Other neurological complications associated with Zika virus such as meningoencephalitis and acute myelitis have also been reported. We now describe the first case of reversible sensory polyneuropathy associated with acute Zika virus infection.

    ReplyDelete
  2. Italian researchers say they've found evidence Zika can affect the brains of adults, and may damage memory.

    The virus is now known to cause devastating damage to the brains of developing fetuses, and there has been some indirect evidence it might get into the brains of adults and children. Now there's more evidence that the virus, once considered benign and boring, is anything but.

    A letter published in the journal Emerging Infectious Diseases describes the case of a 32-year-old volunteer nurse infected with Zika in the Dominican Republic.

    Nine days after she came back from a tour of duty in the Dominican Republic, she visited a clinic with a rash, headache and weakness. She soon had trouble walking and was hospitalized for these neurological symptoms…

    "Complete neuropsychologic examinations (on days nine and 10) showed mild deficits in attention and mental processing speed and mental flexibility and moderate deficits in verbal and nonverbal memory tasks," the team at the National Institute for Infectious Diseases Lazzaro Spallanzani in Rome wrote.

    "In our case, the patient reported early neurologic symptoms and moderate memory impairment in neuropsychologic examinations, all features consistent with the diagnosis of Zika virus-related encephalitis," they added…

    "It raises the possibility that Zika is not simply a transient infection in adult humans and that exposure in the adult brain could have an effect on long-term memory or the risk for depression," they wrote…

    The Italian nurse recovered fully after three weeks.

    http://www.nbcnews.com/storyline/zika-virus-outbreak/zika-affected-woman-s-brain-memory-doctors-say-n647096

    Nicastri E, Castilletti C, Balestra P, Galgani S, Ippolito G. Zika virus infection in the central nervous system and female genital tract [letter]. Emerg Infect Dis. 2016 Dec [date cited]. http://dx.doi.org/10.3201/eid2212.161280

    http://wwwnc.cdc.gov/eid/article/22/12/16-1280_article

    ReplyDelete