October 13, 2021

Adolescents may face many challenges throughout their teenage years, from depression and poor body image to loneliness and even substance abuse. To help address and limit these concerns, researchers are continually looking for connections between the human brain, environment and mental health.

The impact of COVID-19 on adolescent mental health is especially important to address following the social isolation intended to limit the spread of the virus. Yerkes National Primate Research Center neuroscientist Shannon Gourley’s research on the effect of isolation on adolescent mice will be a resource to researchers studying how the COVID-19 pandemic has affected children.

Gourley’s research provides insights into adolescent brain mechanisms. She and her research team discovered mice that have a history of social isolation have higher dendritic spine densities in regions of the brain relevant to decision-making, such as the prefrontal cortex. Social isolation interferes with the pruning of dendritic spines, the structures that underlie connections between neurons.

While we typically think more of something is better, this is not the case for dendritic spines. Instead, such elevated levels related to social adversity experienced during sensitive adolescent periods lead to long-term consequences, despite a typical social environment later in life.

Gourley says, “our findings suggest adolescence is a critical period during which social experience optimizes one’s ability to seek and attain goals later in life.”

Interrupting social experiences may translate into poor choices about homework, food and even hygiene, and that makes Gourley’s research critical now and in the future to help her team and other researchers counter additional, long-term impacts of COVID-19.

September 22, 2021

Pelizaeus-Merzbacher disease is an inherited condition involving the brain and spinal cord, resulting in reduced neurological function. Those affected by the disease (an estimated 1 in 100,000 people) typically experience weak muscle tone, involuntary movements of the eyes, and delayed motor skill development.

In 2016 the Oregon National Primate Research Center (ONPRC)  received a $4 million grant from the National Institutes of Health (NIH) to develop a genomic database for rhesus macaques. Today, the database contains the genomic sequences of over 2,000 monkeys, which has enabled researchers to identify thousands of genetic variants identical to those known to cause human disorders.

Anne Lewis, D.V.M., Ph.D., head of pathology services at ONPRC, observed three young rhesus macaques displaying symptoms, including tremors and motor dysfunction, which were similar to those seen in  human  Pelizaeus-Merzbacher patients. Scientists at ONPRC were able to match her observations with data in the rhesus macaque genome database, helping other scientists to apply therapies to an animal model that closely matches the disease impacting humans. Additional research, led by scientists at Oregon Health & Science University (ONPRCs affiliated institution), could help develop new therapies to treat Pelizaeus-Merzbacher disease.

 “This really sets us up for the possibility of doing gene therapies, or neural stem cell-based therapies in the developing brain,” said Larry Sherman, Ph.D., professor in the Division of Neuroscience at the ONPRC.

To learn more about genome sequencing at the NPRCs, please visit here.

September 1, 2021

Fear struck many when HIV (human immunodeficiency virus) and AIDS (acquired immunodeficiency syndrome) began in the mid-to the late 1970s. No one knew the causes of this mysterious new virus, and there were no treatments, preventions, or cures available. Over the past few decades, scientific advances have enabled patients to receive life-extending treatments and medications. 

The majority of HIV researchers agree that the virus evolved from the closely related simian immunodeficiency virus (SIV), transferring from non-human primates to humans.

CytoDyn Inc., a late-stage biotechnology company developing a drug called leronlimab, released an exciting study in partnership with Oregon National Primate Research Center showing that the drug prevents non-human primates from being infected with simian human immunodeficiency virus (SHIV), a monkey-human chimeric form of HIV. 

“Our study findings indicate leronlimab could be a new weapon against the HIV epidemic,” said Jonah Sacha, Ph.D., an Oregon Health & Science University professor at OHSU’s Oregon National Primate Center and Vaccine & Gene Therapy Institute.

Five clinical trials demonstrate how leronlimab can significantly reduce or control HIV viral load in humans—and ultimately prevent human infection from the virus that causes AIDS. If approved for clinical use, leronlimab will join other AIDS PrEP drugs (“Pre-Exposure Prophylaxis”), medicines taken by individuals who are at risk for exposure to HIV to prevent infection. The drug also benefits other diseases (NASH, cancer, and COVID-19) without the side effects previously experienced from other treatments such as kidney and bone problems.

While the research and trials are still ongoing, early results are promising. To learn more about NPRC research into HIV, please click here.

August 23, 2021

There are approximately 29 million people in the U.S. with Type 2 Diabetes —a lifelong disease that prevents the body from using insulin correctly. While there is currently no cure for the disease, losing weight, eating well and exercising can help to manage it.

The University of Texas Health Science Center at San Antonio, University Health and Texas Biomedical Research recently announced encouraging results following a minimally invasive procedure that dissolved abdominal fat in two Type 2 Diabetes patients. Doctors believe that removing the visceral fat will improve diabetes and slow down the arterial disease.

Before bringing the treatment to humans, doctors utilized the Southwest National Primate Research Center (SNPRC) at Texas Biomedical Research Institute as the site of the large-animal studies. As it turned out, all of the animals treated with mesenteric visceral lipectomy technique, or MVL, survived without any complications, and all had remission of Type 2 Diabetes.

During MVL, a surgeon makes a small abdominal incision and uses a device to dissolve the glycoproteins that hold the fat together and then suctions out the fat without disrupting the blood vessels or surrounding tissues.

“This is important because the fat in our abdomen contains numerous blood vessels,” Richard Peterson, MD, said. “This technique allows the fat to be removed surgically without significant bleeding. Once the fat is loose, it is suctioned out.”

Read more diabetes research from the National Primate Research Centers (NPRCs) here.  

 

Note: The NPRCs will update this blog with our latest COVID-19 news.

Since beginning COVID-19 research in early 2020, NPRC researchers have made encouraging progress in efforts to better understand, diagnose, prevent and treat this novel disease. We’re committed to conducting and enabling research to end this global pandemic and to providing information so the public has ready access to our scientific results.

Our most recent COVID-19 news includes: 

Below is even more information about our extensive and collaborative COVID-19 research:

Diagnostics:

Prevention:

Treatments:

Additional NPRC COVID-19 News:

Bookmark this page so you can easily return here for the latest NPRC COVID-19 research information. We’ve also compiled a list of resources here and provided links to previous NPRC COVID-19 news and national media stories here.

July 20, 2021

Lyme disease, also known as Lyme borreliosis, is an infectious disease caused by Borrelia burgdorferi bacterium, which is spread by ticks. The most common sign of infection is a red rash that appears at the site of the tick bite. Other signals of Lyme include flu-like symptoms, joint pain and weakness in the limbs.

After a 69-year-old woman was diagnosed and repeatedly treated for Lyme disease for 15 years before her death, researchers at the Tulane National Primate Research Center who had previously discovered the persistence of B. burgorferi  despite antibiotic therapy found that the same bacterium was still intact upon autopsy. 

In addition to the typical symptoms of Lyme, she experienced continual neurological decline, including a severe movement disorder and personality changes. The woman eventually passed away after being diagnosed with Lewy body dementia— a disease that presents itself with similar declined motor functions of Parkinson’s Disease with the added element of significant memory issues.  

The Tulane research team found that her central nervous system (CNS) still harbored intact spirochetes despite aggressive antibiotic therapy for Lyme disease at different times throughout her illness. The findings may lead to a correlation between Lyme disease and Lewy body dementia.

“These findings underscore how persistent these spirochetes can be in spite of multiple rounds of antibiotics targeting them,” said Monica Embers, associate professor of microbiology and immunology at Tulane. “We will be interested in investigating the role that B. burgdorferi may play in severe neurological disease, as this is an area of research that has not yet been fully explored.”

To learn more about research being done by Tulane NPRC, please visit here.

July 13, 2021

HIV (human immunodeficiency virus) attacks the body’s immune system, and if left untreated, HIV can lead to AIDS (acquired immunodeficiency syndrome). HIV/AIDS currently impacts 38 million people worldwide. While there is no cure yet, proper medical care can control the disease and allow for a relatively long and healthy life. In particular, antiviral therapy (ART) is the current leading treatment for HIV/AIDS and can reduce the virus to undetectable levels. 

Yerkes National Primate Research Center researchers, in collaboration with Institut Pasteur, recently determined that when added to ART, a combination immunotherapy of Interleukin-21 (IL-21) and interferon alpha (IFNɑ) is effective in generating highly functional natural killer (NK) cells that can help control and reduce simian immunodeficiency virus (SIV), the primate equivalent to HIV, content in tissue.

“Our results indicate the ART plus combo-treated rhesus monkeys showed enhanced antiviral NK cell responses,” says Justin Harper, lab manager of Dr. Mirko  Paiardini’s research lab at Yerkes. “These robust NK cell responses helped clear cells harboring virus in lymph nodes, which is normally shielded from robust immune responses and serves as a critical tissue that supports viral persistence.”

These new findings open the door to additional treatment strategies to help support remission without using ART, a costly treatment option that requires strict, long-term adherence. Ultimately, the researchers are working to reduce the burden of HIV to individuals and the world. To learn more about NPRC research into HIV/AIDs, please visit here. 

June 22, 2021

About 30 percent of people who have severe anxiety and depression do not find sufficient relief in available medications and psychotherapy, causing them chronic, debilitating symptoms and a significant risk of suicide. To help end this debilitation, University of Wisconsin–Madison researcher Ned Kalin, MD, and his team are studying how to dial down overactive responses to potential threats.

The researchers are using an established method, called DREADDs (Designer Receptors Exclusively Activated by Designer Drugs), in monkeys at the Wisconsin National Primate Research Center (WiNPRC) to make small changes to genes in targeted cells to alter cell behavior. The idea is to coax neurons to produce a unique version of a protein, called a receptor. These “designer receptors” can receive chemical signals that regulate the cells’ function and affect how they communicate with other cells. Unlike other receptors in the brain that respond to naturally occurring chemical signals, the DREADDs only respond to a chemical not naturally present — a “designer” drug matched to the designer receptor.

“When such a drug interacts with DREADDs, you have the possibility of ‘fine-tuning’ the function of the brain cell that is now expressing this receptor,” says Patrick Roseboom, PhD, senior scientist and a lead study author.

The researchers injected a low dose of a psychiatric medication, Clozapine, in five monkeys to activate DREADDs in cells in the amygdala, the brain region responsible for regulating emotions. The researchers then tested the monkeys in a mildly stressful situation, placing them near an unfamiliar human, which is similar to how healthcare professionals assess anxiety levels in children. The researchers’ observations of the monkeys’ behavior and levels of stress hormones showed the most anxious monkeys freeze — becoming quiet and very still.

When the researchers gave the Clozapine before the stressful situation, the monkeys with the DREADDs experienced a significant reduction in freezing, while a control group without the DREADDS showed no change in behavior. 

The success of this proof-of-concept study is providing hope for using gene therapy and methods, such as DREADDs, to treat the millions of people who live with severe and treatment-resistant psychiatric illnesses. Read more about the NPRCs’ anxiety and depression research here.

 

June 8, 2021

Tuberculosis (TB) is a serious infectious disease that typically affects the lungs. Spread of TB typically occurs in the air via coughs or sneezes. Treatment often poses a challenge to immunologists, as it represents a chronic infection characterized by persistence of the pathogen despite development of antigen-specific immune responses.

Researchers at Emory University and the Yerkes National Primate Research Center have completed the first study to report on temporal dynamics of Mycobacterium tuberculosis (Mtb)-specific T cell responses in latent Mtb infection. With it, they discovered the T cell response emerged as early as three weeks post infection and continued throughout the six-month study. 

“Because TB is the leading infectious disease killer, claiming 1.5 million lives every year, we want to know why some people who are infected with Mtb progress to TB disease while others remain asymptomatic and do not,” says Jyothi Rengarajan, PhD, lead author and associate professor of medicine, Division of Infectious Diseases, Emory University School of Medicine and a researcher at the Emory Vaccine Center and Yerkes National Primate Research Center. 

Because TB is difficult to assess in humans, researchers worked with primates because they develop and respond to the disease much like humans do

Rengarajan states, “Monkeys develop and respond to latent TB infection similar to the way humans do, which makes them an excellent translational model for studying the immunological basis for asymptomatic TB and then applying the results to humans and animals.”

Findings proved the rapid response of T cells, and knowing where to activate them (lungs versus blood) will help researchers create better treatments and even a vaccine to prevent TB infections.

NPRC researchers are working to find new potential treatments and cures for this infectious disease. Take a look at some of our other recent studies to learn about the progress we’ve made toward a TB-free world.

May 25, 2021

Each year in the U.S., millions of people receive general anesthesia, and a small proportion of those patients actually regain some awareness during their medical procedures.

A recently published study about brain activity representing consciousness could help prevent that potential trauma as well as help scientists define which parts of the brain are key to the conscious mind. Such information could lead to more accurate measurements of patients undergoing anesthesia, improve treatment outcomes for people who have consciousness disorders and help people in comas maintain a continuous level of consciousness.

Yuri Saalmann, a University of Wisconsin-Madison psychology and neuroscience professor, and his research team recorded electrical activity in about 1,000 neurons surrounding each of 100 sites throughout the brains of a pair of monkeys at the Wisconsin National Primate Research Center (WiNPRC). The researchers recorded activity during several states of consciousness: under drug-induced anesthesia, light sleep, resting wakefulness and roused from anesthesia into a waking state through electrical stimulation of a spot deep in the brain.

To sift out characteristics that best indicate whether the monkeys were conscious or unconscious, the researchers used machine learning. They input their large pool of data into a computer, told the computer which state of consciousness had produced each pattern of brain activity and asked the computer which areas of the brain and patterns of electrical activity corresponded most strongly with consciousness.

Surprisingly, the results pointed away from the frontal cortex, which is the part of the brain healthcare professionals typically monitor to maintain patient safety while under general anesthesia and the part most likely to exhibit slow waves of activity long considered typical of unconsciousness.

“In the clinic now, they may put electrodes on the patient’s forehead,” says Mohsen Afrasiabi, an assistant scientist in Saalmann’s lab. “We propose that the back of the head is a more important place for those electrodes because we’ve learned the back of the brain and the deep brain areas are more predictive of state of consciousness than the front.”

And while both low- and high-frequency activity can be present in unconscious states, complexity best indicates a waking mind. “You need more complexity to convey more information, which is why it’s related to consciousness,” says graduate student Michelle Redinbaugh. “If you have less complexity across these important brain areas, they can’t convey very much information. You’re looking at an unconscious brain.”

Read more about our consciousness research and how monkeys are helping improve patient care here.

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