Tag Archives: monkey

Zika research in nonhuman primates critical as fears among pregnant women, families grow

Jordana Lenon, B.S., B.A., is the outreach specialist for the Wisconsin National Primate Research Center and the Stem Cell & Regenerative Medicine Center, both at the University of Wisconsin-Madison. In this guest post Jordana talks about WNPRC research on Zika virus.

Wisconsin National Primate Research Center scientist David O’Connor is emphasizing using “as few animals as possible” to answer research questions that desperately need answers as the world watches Zika virus cause birth defects and raise fears among pregnant women and their families across the warmer Americas. These answers, O’Connor expects, will move him and his collaborators at the University of Wisconsin-Madison, Duke University, in Brazil and beyond forward as they learn more each day how Zika virus may be operating inside of infected pregnant women and their newborns, and could cause potential lifelong impairments we don’t even know about yet.

Researchers at the Wisconsin National Primate Research Center perform a fetal ultrasound on a pregnant rhesus macaque, in their quest to learn more about the link between the Zika virus and birth defects. (Images by Justin Bomberg, UW-Madison Communications)

Thanks to research using rhesus macaques, whose immune, reproductive and neurological systems are very similar to ours, the answers are starting to come in. Furthermore, O’Connor and his Zika Experimental Science Team, or “ZEST are sharing their raw research data through an online portal with the public – including of course and very importantly other Zika researchers. Their goal is to share data openly, to eliminate as many impediments as possible to spurring collaborative work around the globe to solve the Zika crisis.

David O'Connor, professor in the Department of Pathology and Laboratory Medicine at the University of Wisconsin-Madison, is pictured on April 19, 2016. (Photo by Bryce Richter / UW-Madison)

David O’Connor, professor in the Department of Pathology and Laboratory Medicine at the University of Wisconsin-Madison, is pictured on April 19, 2016. (Photo by Bryce Richter / UW-Madison)

Just how severe a problem are we looking at? O’Connor gave some perspective during a public lecture on the UW-Madison campus this week. While HIV – another pandemic virus he has studied exhaustively over the past 20 years – costs society about $400,000 per patient over their life spans, Zika virus impairments in newborns could cost between $1-10 million per patient (using US dollar estimates) over their life spans. Recent studies in macaques found that the Zika virus persisted for up to 70 days in the blood of pregnant female monkeys – much longer than the 10 days it remained in either males or non-pregnant females – this increases the chance of severe birth defects being found in babies.

There are already more than 300 pregnant women in the US with laboratory evidence of Zika. This number is growing daily. Infections in the US are largely being attributed to pregnant women picking up the virus while traveling outside the country: Zika is hitting hard right now in Puerto Rico, infecting nearly 50 pregnant women per day, as Aedes aegypti mosquitos, which can transmit viruses such as dengue and Zika, spread and move northward this summer from South to Central America, to the Caribbean and into the United States. Because Zika is also sexually transmitted, its borders of infection are not limited to places where the mosquitos live and bite.

Mother and infant rhesus monkeysThere is hope, however. A new experimental vaccine has shown to protect mice with just a single dose. Scientists from Walter Reed Army Institute of Research, the Beth Israel Deconess Medical Center and Harvard Medical School found two different vaccines effectively protected 100% of mice from the virus. This compares to a control group which were unprotected and all caught Zika after being exposed to the virus.

Jordana Lenon

See the team’s latest research updates on the ZEST web portal site.

View the Wednesday Night at the Lab lecture on Zika virus that Dr. O’Connor gave July 6 on the UW-Madison campus, including his responses to several questions about the virus, immunity, pregnancy, and vaccine development.

Macaque study explores best route of oxytocin administration

Oxytocin is a natural brain peptide most commonly thought of as the “love hormone” for its role in social bonding: it spikes during social contact, play, cuddling, and sex. Because of extensive research in animals including prairie voles, sheep, and monkeys demonstrating that oxytocin promotes affiliative behaviors and social bonding1,2, oxytocin is increasingly being studied for its effects on humans3. The jury is still out here: some studies show that oxytocin has no effect on social behavior, whereas others show a negative effect. The most attention, however, is given to those studies showing a positive effect, particularly in individuals with social deficits like those with autism spectrum disorder (ASD)4.

Consequently, oxytocin nasal sprays are increasingly being advertised as treatments for ASD, despite the inconclusive results from clinical trials and a lack of studies showing their long-term efficacy and side effects. These sprays are available online without a prescription but they are not regulated by the FDA. Thus little is known about the quantity of oxytocin they contain, their efficacy, or possible side effects.

Though nasal sprays are commonly used in clinical trials for ASD, oxytocin is often administered intravenously (IV). In both cases, study designs differ in the amount of oxytocin they use, the duration of treatment, and the delivery method, so it is no surprise that they have yielded conflicting results. Thus, the mechanisms by which oxytocin administered in different ways may act in the brain are unclear.

Macaque Monkey

Image Credit: Amanda M. Dettmer

An important and timely study just published online in Psychoneuroendocrinology by researchers at the California National Primate Center and the University of California-Davis tackles some of these methodological questions. Rhesus monkeys were implanted with intrathecal catheters to allow for repeated sampling of cerebrospinal fluid (CSF) in awake animals, and were treated with either intranasal (IN) or IV oxytocin at three different doses in a randomized, crossover study design (meaning animals were randomly assigned to IN, then IV, or vice versa). Blood and CSF samples were collected from awake animals (thus eliminating possible confounds of anesthesia) pre-dose (0 minutes), and at 5, 15, 30, 60, and 120 minutes after oxytocin administration. Importantly, this is the first study to use awake monkeys for oxytocin administration and sample collection, to directly compare more than two different doses of oxytocin in the same subjects, and to collect five concurrent post-oxytocin blood and CSF samples in a relatively short period. These methods would be extremely difficult, if not impossible, to carry out in human subjects.

The researchers found that blood and CSF levels of oxytocin were higher after IV vs. IN administration. Furthermore, they found that IV-administered oxytocin elevated blood and CSF oxytocin for a period of up to 30 minutes, whereas IN oxytocin had no effect on blood levels of oxytocin, regardless of the dose – an unexpected finding because IV oxytocin does not cross the blood-brain barrier5. The authors postulate that elevated levels of oxytocin in the bloodstream after IV oxytocin treatment might result in the release of oxytocin in the brain (as observed in CSF) via mechanisms that have yet to be identified, but which studies using nonhuman primate models will be critical for disentangling. They also argue that humans can be instructed to inhale deeply during IN administration, whereas animals cannot, yielding important methodological implications for studies relying on animal models of human behavior. Finally, the group reported that blood oxytocin cannot be used as a reference for CSF oxytocin (thus supporting earlier findings), yet most human studies rely on measuring blood oxytocin after oxytocin treatment.

The authors conclude that, “…it is…critical to use nonhuman primate models to better evaluate the effectiveness of the delivery method most commonly used in human studies and clinical use – the nasal spray.”6 Indeed, studies like this one are critical for informing dosing regimens and administration methods of oxytocin in humans, as we cannot conduct such detailed studies without animal models. Ultimately, animals – specifically nonhuman primates – will be key for identifying and understanding the mechanisms by which oxytocin and other drugs act to affect brain and behavioral responses.

Amanda M. Dettmer

References

  1. Stoesz, Hare & Snow, 2013, Neurosci Biobehav Rev, 37(2):123-32.
  2. Lim & Young, 2006, Hormones & Behavior, 50:506-17.
  3. Kuehn, 2011, JAMA, 305(7):659-61.
  4. Young & Barrett, 2015, Science, 347(6224):825-26.
  5. Ermisch et al., J Cereb. Blood Flow Metab, 5:350-57.
  6. Freeman et al., 2016, PNEC, 66:185-94.

PR, ethics, and the science of head transplants

There has been a lot of media coverage on the recent claims by Dr. Sergio Canavero that he has successfully transplanted the head of a monkey on to a donor body of another monkey. This story, originally posted by the New Scientist, has since gone viral with some touting miracle cures for paralysis, while others have publicly expressed outrage and disgust. As pointed out by the New Scientist, this is not science, or at the least, not yet. Until the veil of secrecy concerning the conduct of this study is made transparent – no formal conclusions can be made and one can only speculate in regards to the quality of the experiment that was performed. Moreover, as this work still has to pass through the peer-review process, it remains unclear whether this is simply an attempt at publicity. As Arthur Caplan, a New York University bioethicist told New Scientist:

It’s science through public relations. When it gets published in a peer reviewed journal I’ll be interested. I think the rest of it is BS”

So far, the only evidence that Dr Canavero has produced is a picture of a monkey which appears to have had a head/body transplant, as well as a short video of a mouse moving around (despite significant impairments), which also appears to have a transplant (but how long did they live for? When Dr Canavero’s colleague Dr Xiaoping Ren of China’s Harbin Medical University carried out similar head transplants in mice in 2015 they all died within a few minutes of being revived after surgery). While the monkey “fully survived the procedure without any neurological injury of whatever kind”, according to Canavero, it was euthanized after 20 hours for “ethical reasons”. The media storm surrounding this story appears to play up to the researcher’s aims – to find financial backing to continue his research and then move it into humans.

Canavero at TEDx

Two pieces of information in the article by the New Scientist bear scrutiny. The first is that Canavero is quoted as saying “this experiment, which repeats the work of Robert White in the US in 1970, demonstrates that if the head is cooled to 15°C, a monkey can survive the procedure without suffering brain injury.” Second, Sam Wong, author of the article in the New Scientists stated “they connected up the blood supply between the head and the new body, but did not attempt to connect the spinal cord.” Careful reading highlights a simple fact, this study is not novel in any regard – this is a replication of the work by Robert White and is quite simply a “head transplant”. Thus, the same criticisms that were levied in regards to the original experiment by Robert White apply here. As Stephen Rose, director of brain and behavioural research at Open University can be quoted as saying in 2001:

This is medical technology run completely mad and out of all proportion to what’s needed. It’s entirely misleading to suggest that a head transplant or a brain transplant is actually really still connected in anything except in terms of blood stream to the body to which it has been transplanted. It’s not controlling or relating to that body in any other sort of way. It’s scientifically misleading, technically irrelevant and scientifically irrelevant, and apart from anything else a grotesque breach of any ethical consideration. It’s a mystification to call it either a head transplant or a brain transplant. All you’re doing is keeping a severed head alive in terms of the circulation from another animal. It’s not connected in any nervous sense.”

And so, it is worth reflecting at this juncture on the moral and ethical issues surrounding this controversial procedure. Let us assume for a moment that this procedure is in fact feasible. In the original studies by Robert White and Vladimir Demikov, it was made clear that these experiments were lethal for the animal. Simply put, while the head of the animal was capable of “seeing, hearing, tasting, smelling”; none of the other regulatory processes were intact (e.g. breathing) as there was no control over the donor body. Furthermore, like many tissue transplants, rejection of the donor body from the immune system is a large possibility, immunorejection was after all the cause of death in the monkey whose head Dr White transplanted in 2001. Indeed, Canavero has yet to demonstrate any kind of proof of principle with regeneration of nervous tissue with any meaningful metric of control of the donor body.

Perhaps the most interesting insight into Canavero’s thinking comes from a quotation in the New Scientist article where he says:

Gene therapy has failed. Stem cells, we’re still waiting. Even if they come now, for these patients there is no hope. Tetraplegia can only be cured with this. Long term, the body decays, organs decay. You have to give them a new body because even if you take care of the cord, you’re going nowhere.”

These remarks by Canavero are somewhat naive as both gene therapy and stem cell therapy have made substantial advances in recent years, with many therapies now in clinical trials. Furthermore, the claim that “Tetraplegia can only be cured with this [head transplant]” flies in the face of evidence from recent successful animal and clinical trials on a variety of innovative therapies for paralysis, including epidural stimulation, intraspinal microstimulation, neuroprosthesis, and stem cell therapy.

There have recently been a series of major advances in treating paralysis, including epidural stimulation.

There have recently been a series of major advances in treating paralysis, including epidural stimulation.

While there is mounting evidence from studies in rodents that the polyethylene glycol (PEG) implantation approach favored by Canavero may be able to promote repair of injured spinal cord and recovery of motor function in paralyzed limbs, his casual dismissal of the work of other scientists – while often simultaneously citing their work in support of his own approach – exemplifies his arrogance. He would be better off lending his expertise to the work of others who are exploring the potential for PEG in spinal cord repair, work that has the potential to benefit millions of people, but instead appears set on a self-aggrandizing PR campaign in support of an approach that if successful – which seems highly unlikely even if the surgery is a technical success – can only benefit a tiny number of people…potentially at the cost of depriving many other transplant patients of much needed organs.

The reality, however, remains that the procedure exposes the patient (be it mouse, monkey or human) to far greater risks compared to the potential benefits. Indeed, these experiments would never be approved in countries which have strict review criteria, with a clear harm/benefit analysis needing to be performed before such a study is given approval. In these circumstances, the news that leading experts in animal research in China are currently undertaking a major revision to the country’s national regulation on the management of laboratory animals is timely.

But these issues are not unknown to Dr. Canavero. Indeed, as can be seen here (scroll to see response), and in what can only be described as derision and a willful skirting of the law, Dr. Canavero remains set to push forward with his ideas regardless of the consequences. For these reasons we have the gravest of reservations about the course being followed by Dr. Canavero and his colleagues, and call on them to halt this research until a full independent review of the scientific evidence and impact on potential patients can be undertaken.

Jeremy Bailoo and Justin Varholick

The opinions expressed here are our own and do not necessarily reflect the interests of the the University of Bern or the Division of Animal Welfare at the University of Bern.

Announcement About NIH Monkey Research Leaves Unanswered Questions

Late Friday, Buzzfeed broke a story reporting on the planned phase-out of on-site housing of monkeys at one of the National Institutes of Health intramural laboratories, the National Institute of Child Health and Human Development (NICHD) Laboratory of Comparative Ethology in Poolesville, Maryland. As NICHD Director  Constantine Stratakis outlined in an interview with Science News, the phase-out has been in the planning stages for some time and reflects a combination of economic considerations, the age of the facility, and the eventual retirement of the lab’s 69-year old head, a scientist whose 30+ year career has– and continues– to produce a great many important discoveries. Unfortunately, as we’ve seen with other recent announcements about primate research, the news left many with questions and impressions about broader impacts.

Monkeys involved in developmental and behavioral research at Stephen Suomi's lab in Poolesville

Monkeys involved in developmental and behavioral research at Stephen Suomi’s lab in Poolesville, Maryland.

What is clear is that the science is valuable and that the work is conducted with care for the animals (see previous NIH reports, here). Science is the essential foundation of medical progress and discovery that benefits society, humans, animals, and the environment. Dr. Stephen Suomi and his scientific collaborators – leading scientists around the world — have together made scientific discoveries that are reflected in over 500 published papers. (see list here).

The significance of those findings is reflected in the over 10,000 times Suomi’s papers have been cited in peer-reviewed publications. The citations are by a broad range of clinicians and by scientists studying humans and other animals in order to better understand genetics, immunology, neurobiology, pharmacology, behavior and other aspects of health. The esteem in which this work is held was clear in statements of support issued by both the  American Psychological Association and American Society of Primalogists (ASP) earlier this year,  as well as the NIH’s own response to PETA’s allegations last January.

Dr. Suomi’s collaborators include over 60 scientists – with PhDs and MDs – from five different institutes at NIH and 40 different institutions, universities and research centers, including those from 7 different countries outside of the US.

The US is a leader in funding medical and scientific research that benefits people around the globe. NIH’s own research centers – the intramural program – provides scientists and students from all over the world the opportunity to conduct research, make discoveries, and train the next generation of basic and clinical researchers.

The NIH has not ended primate research within the intramural program.  There are many scientists and laboratories whose work depends on humane, ethical studies of monkeys. Those studies continue.

It is work that has contributed to new understanding of a broad range of threats to human health and well-being —stroke, Parkinson’s disease, autism, depression, cancer, diabetes, addiction, and more. The list is long and includes diseases that touch nearly everyone, resulting in suffering and harm that scientists are obliged to address with expert knowledge and training, using the best approaches to discovery that they have available now.

The science is led by experts working for the public to make the world better for the public. The US has a strong system for direction, review, and oversight of animal research.  The public contributes to that via its elected representatives. Political campaigns by groups fundamentally opposed to all use of animals in research threaten the very fabric of science on which medical progress depends.  The public should be concerned about efforts to undermine science and medicine. The future depends on serious, fact-informed, and thoughtful dialogue.  Anything less is a serious harm to public interests in science and to future generations.

Speaking of Research

 

Truvada prevents HIV infection in high-risk individuals! A clinical success built on animal research

In the past two weeks we’ve learned of a major advance in ongoing efforts to halt the spread of  HIV, two separate clinical studies have reported that a daily regimen of a pill called Truvada as a pre-exposure prophylaxis (PrEP) is highly effective in preventing infection in high risk groups. This success is a result not just of the dedication of the clinicians who conducted these trials, but also of a series of pivotal studies conducted in non-human primates more than a decade ago that laid the scientific foundations for them.

In the first study of more than 600 high-risk individuals conducted at Kaiser Permanente in San Francisco, which was published in the journal Clinical Infectious Diseases, researchers found that Truvada – a combination of the anti-viral drugs tenofovir and emtricitabine – was 100% effective in preventing infection.  In the 2nd  study, called the PROUD study and published online this week in the Lancet, of more than 500 high-risk men undertaken in 13 sexual health clinics in England Truvada reduced infections by 86%.

Truvada prevents HIV transmission in high-risk individuals. Image: AFP / Kerry Sheridan

Truvada prevents HIV transmission in high-risk individuals. Image: AFP / Kerry Sheridan

These results have been greeted with enthusiasm in media reports, with headlines such as “Aids vanquished: A costly new pill promises to prevent HIV infection” , “A pill designed to prevent HIV is working even better than people thought” and  “Truvada Protected 100 Percent Of Study Participants From HIV: This is exciting!”. It’s worth noting that these are not the only trials to show the potential for Truvada to block HIV infection, earlier trials in Kenya, Uganda and Botswana also showed that it could substantially reduce infection rates, including in heterosexual couples where one partner was HIV positive and the other was not. There has been some concern that those taking Truvada would be less likely to take other safe sex measures – such as using condoms – but the results of the PROUD study showed no difference in acquisition of other sexually transmitted infections between those who started Truvada treatment immediately and those who delayed for 1 year, suggesting that they did not engage in riskier behavior as a consequence of taking Truvada.

Thanks to a multi-pronged approach to preventing HIV infection, combining barrier methods such as condoms,  Highly Active Antiretroviral Therapy (HAART) to lower viral load in infected individuals, and the use of antiviral medications to prevent mother-to-child transmission, the spread of HIV infection has slowed dramatically in many regions of the world, and pre-exposure prophylaxis with Truvada certainly has the potential to help reduce it further.

As we applaud the researchers who conducted these first real-world evaluations of Tenofovir in high-risk populations, it is also a good opportunity to remember the researchers whose work led us to this point. One of those pioneers is Dr. Koen Van Rompay, a virologist at the University of California at Davis who played a key role in the early development of Tenofovir and  its evaluation in pre- and post- exposure phophylaxis in macaque models of HIV infection. In 2009 Dr Van Rompay wrote an article for Speaking of Research explaining how important animal research was to the early development of such HIV prophylaxis regimes, and how important it continues to be as scientists develop ever better treatments, which we share again today:

Contributions of nonhuman primate studies to the use of HIV drugs to prevent infection – Koen van Rompay

Since the early days of the HIV pandemic, as soon as it was clear that an effective HIV vaccine would still be years away, there has been considerable interest in using anti-HIV drugs to reduce the risk of infection following exposure to HIV (so-called prophylaxis). Animal models of HIV infection, especially the rhesus macaque, have played a major role in developing and testing these treatments.

The development of HIV drugs to treat HIV-infected persons has shown that many compounds that are effective in vitro (i.e., in tissue culture assays) fail to hold their promise when tested in humans, because of unfavorable pharmacokinetics, toxicity or insufficient antiviral efficacy. The same principles apply to the development of drugs to prevent HIV infection. The outcome of drug administration is determined by many complex interactions in vivo between the virus, the antiviral drug(s) and the host; with current knowledge, these interactions cannot be mimicked and predicted sufficiently by in vitro studies or computer models.

Testing different compounds in human clinical trials is logistically difficult, time-consuming and expensive, so only a very limited number of candidates can be explored in a given time. Fortunately, the development of antiviral strategies can be accelerated by efficient and predictive animal models capable of screening and selecting the most promising compounds. No animal model is perfect and each model has its limitations, but the simian immunodeficiency virus (SIV) of macaques is currently considered the best animal model for HIV infection because of the many similarities of the host, the virus and the disease. Non-human primates are phylogenetically the closest to humans, and have similar immunology and physiology (including drug metabolism, placenta formation, fetal and infant development). In addition, SIV, a virus closely related to HIV-1, can infect macaques and causes a disease that resembles HIV infection and AIDS in humans, and the same markers are used to monitor the disease course. For these reasons, SIV infection of macaques has become an important animal model to test antiviral drugs to prevent or treat infection.

Studies in rhesus macaques first indicated that Tenofovir could block HIV infection. Photo: Understanding Animal Research

Studies in rhesus macaques first indicated that Tenofovir could block HIV infection. Photo: Understanding Animal Research

Different nonhuman primate models have been developed based on the selection of the macaque species, the particular SIV strain and the inoculation route (e.g. IV injection, vaginal exposure) used (reviewed in (33)). These models have been improved and refined during the past two decades. For example, SIV-HIV chimeric viruses have been engineered to contain portions of HIV-1, such as the enzyme reverse transcriptase (“RT-SHIV”) that the virus requires in order to multiply or the envelope protein (“env-SHIV”) that the virus needs if it is to escape from a cell and infect other cells, to allow these models to also test drugs that are specific for HIV-1 reverse transcriptase or envelope (28, 35).

Many studies in non-human primates have investigated whether the administration of anti-HIV drugs prior to or just after exposure to virus can prevent infection. The earliest studies indicated that drugs such as the reverse transcriptase inhibitor zidovudine (AZT), the first approved drug treatment for HIV, were not very effective in preventing infection, but a likely reason for this was the combination of a high-dose viral inoculums used, the direct intravenous route of virus inoculation, and the relative weak potency of drugs at that time (2, 4, 13, 19, 20, 36). The proof-of-concept that HIV drugs can prevent infection was demonstrated in 1992 when a 6-weeks zidovudine regimen, started 2 hours before an intravenous low-dose virus inoculation that more accurately represented HIV infection in humans, protected infant macaques against infection (29). These results were predictive of a subsequent clinical trial (Pediatric AIDS Clinical Trials Group Protocol 076), which demonstrated that zidovudine administration to HIV-infected pregnant women beginning at 14 to 34 weeks of gestation, and continuing to their newborns during the first 6 weeks of life reduced the rate of viral transmission by two-thirds (10).

Since then, a growing number of studies have been performed in macaques to identify more effective and simpler prophylactic drug regimens. These studies generally used lower virus doses, sometimes combined with a mucosal route of virus inoculation that mimics vaginal or anal exposure responsible for the majority of human HIV infections. These studies demonstrated that administration of some newer anti-HIV drugs, including the reverse transcriptase inhibitors adefovir (PMEA), tenofovir (PMPA), and emtricitabine (FTC) that prevent the virus from multiplying in the infected cell, and the CCR5 inhibitor CMPD167 that stops the virus from binding the CCR5 receptor on the cell surface and entering a cell in the first place, starting prior to, or at the time of virus inoculation, was able to prevent infection, though with varying success rates (3, 4, 16, 24, 25, 31, 34, 35). Only very few compounds such as the reverse transcriptase inhibitors tenofovir, BEA-005 and GW420867, and the CCR5 inhibitor CMPD167, were able to reduce infection rates when treatment was started after virus inoculation. For those drugs that were successful in post-exposure prophylaxis studies, a combination of the timing and duration of drug administration was found to determine the success rate, because a delay in the start, a shorter duration, or interruption of the treatment regimen all reduced the prophylactic efficacy (5, 11, 21, 22, 26, 27, 31) , information that has guided the design of subsequent clinical trials.

While some of the compounds such as GW420867 that showed prophylactic efficacy in the macaque model are no longer in clinical development (e.g., due to toxicity or pharmacokinetic problems discovered later in pre-clinical testing), the very promising results achieved with tenofovir have sparked further studies aimed at simplifying the prophylactic regimen. Several studies in infant and adult macaques have demonstrated that short or intermittent regimens of tenofovir (with or without coadministration of emtricitabine) consisting of one dose before and one dose after each virus inoculation were highly effective in reducing SIV infection rates (15, 30, 32).

The demonstration at the beginning of the 1990’s that anti-HIV drugs can prevent infection in macaques has provided the rationale to administer these compounds to humans to reduce the likelihood of infection in several clinical settings. Antiviral drugs are now recommended, usually as a combination of several drugs, to reduce the risk of HIV infection after occupational exposure (e.g., needle-stick accidents of health care workers) and non-occupational exposure (e.g. sex or injection-drug use) (6, 7). As mentioned previously, drug regimens containing zidovudine and more recently also more potent drugs such as nevirapine have proven to be highly effective in reducing the rate of mother-to-infant transmission of HIV, including in developing countries (10, 14, 17), and save many thousands of lives every year . Because the short nevirapine regimen that is given to pregnant HIV-infected women at the onset of labor frequently induces drug resistance mutations in the mother that may compromise future treatment (12), tenofovir’s high prophylactic success in the infant macaque model has sparked clinical trials in which a short tenofovir-containing regimen was added to existing perinatal drug regimens to reduce the occurrence of resistance mutations and/or further lower the transmission rate (8, 9, 18, 30, 32).

Scanning electron micrograph of HIV-1, colored green, budding from a cultured lymphocyte. Photo: C. Goldsmith Content Providers: CDC/ C. Goldsmith, P. Feorino, E. L. Palmer, W. R. McManus

Scanning electron micrograph of HIV-1, colored green, budding from a cultured lymphocyte. Photo: C. Goldsmith Content Providers: CDC/ C. Goldsmith, P. Feorino, E. L. Palmer, W. R. McManus

Because an efficacious HIV vaccine has so far not been identified, the concept of using pre-exposure prophylaxis also as a possible HIV prevention strategy in adults has gained rapid momentum in recent years. The promising prophylactic data of tenofovir (with or without emtricitabine) in the macaque model (23, 32, 35, 37) combined with the favorable pharmacokinetics, safety profile, drug resistance pattern and therapeutic efficacy of these drugs in HIV-infected people, have pushed these compounds into front-runner position in ongoing clinical trials that investigate whether uninfected adults who engage in high-risk behavior will have a lower infection rate by taking a once daily tablet of tenofovir or tenofovir plus emtricitabine. The results of these ongoing trials are highly anticipated. An overview of the design, status and challenges of these trials which are currently underway at several international sites and target different high-risk populations can be found on the website of the AIDS Vaccine Advicacy Coalition (1, 23).

In conclusion, nonhuman primate models of HIV infection have played an important role in guiding the development of pre- and post-exposure prophylaxis strategies. Ongoing comparison of results obtained in these models with those observed in human studies will allow further validation and refinement of these animal models so they can continue to provide a solid foundation to advance our scientific knowledge and to guide clinical trials.

Koen van Rompay DVM Ph.D. is a research virologist at the California National Primate Research Center at UC Davis.

Cited literature
1. AIDS Vaccine Advocacy Coalition. August 2008, posting date. Anticipating the results of PrEP trials. http://avac.org/prep08.pdf
2. Black, R. J. 1997. Animal studies of prophylaxis. Am. J. Med. 102 (5B):39-43.
3. Böttiger, D., P. Putkonen, and B. Öberg. 1992. Prevention of HIV-2 and SIV infections in cynomolgus macaques by prophylactic treatment with 3′-fluorothymidine. AIDS Res. Hum. Retrovir. 8:1235-1238.
4. Böttiger, D., L. Vrang, and B. Öberg. 1992. Influence of the infectious dose of simian immunodeficiency virus on the acute infection in cynomolgus monkeys and on the effect of treatment with 3′-fluorothymidine. Antivir. Chem. Chemother. 3:267-271.
5. Böttiger, D., N. G. Johansson, B. Samuelsson, H. Zhang, P. Putkonen, L. Vrang, and B. Öberg. 1997. Prevention of simian immunodeficiency virus, SIVsm, or HIV-2 infection in cynomolgus monkeys by pre- and postexposure administration of BEA-005. AIDS 11:157-162.
6. Centers for Disease Control and Prevention. 1996. Update: provisional Public Health Service recommendations for chemoprophylaxis after occupational exposure to HIV. MMRW 45:468-472.
7. Centers for Disease Control and Prevention. 2005. Antiretroviral postexposure prophylaxis after sexual, injection-drug use, or other nonoccupational exposure to HIV in the United States: recommendations from the U.S. Department of Health and Human Services. MMWR 54:1-19.
8. Chi, B. H., M. Sinkala, F. Mbewe, R. A. Cantrell, G. Kruse, N. Chintu, G. M. Aldrovandi, E. M. Stringer, C. Kankasa, J. T. Safrit, and J. S. Stringer. 2007. Single-dose tenofovir and emtricitabine for reduction of viral resistance to non-nucleoside reverse transcriptase inhibitor drugs in women given intrapartum nevirapine for perinatal HIV prevention: an open-label randomised trial. Lancet 370:1698-705.
9. Chi, B. H., N. Chintu, R. A. Cantrell, C. Kankasa, G. Kruse, F. Mbewe, M. Sinkala, P. J. Smith, E. M. Stringer, and J. S. Stringer. 2008. Addition of single-dose tenofovir and emtricitabine to intrapartum nevirapine to reduce perinatal HIV transmission. J. Acquir. Immune Defic. Syndr. 48:220-3.
10. Connor, E. M., R. S. Sperling, R. Gelber, P. Kiselev, G. Scott, M. J. O’Sullivan, R. VanDyke, M. Bey, W. Shearer, R. L. Jacobson, E. Jiminez, E. O’Neill, B. Bazin, J.-F. Delfraissy, M. Culnane, R. Coombs, M. Elkins, J. Moye, P. Stratton, J. Balsley, and for the Pediatric AIDS Clinical Trials Group Protocol 076 Study Group. 1994. Reduction of maternal-infant transmission of human immunodeficiency virus type 1 with zidovudine treatment. N. Engl. J. Med. 331:1173-1180.
11. Emau, P., Y. Jiang, M. B. Agy, B. Tian, G. Bekele, and C. C. Tsai. 2006. Post-exposure prophylaxis for SIV revisited: Animal model for HIV prevention. AIDS Res. Ther. 3:29.
12. Eshleman, S. H., M. Mracna, L. A. Guay, M. Deseyve, S. Cunningham, M. Mirochnick, P. Musoke, T. Fleming, M. G. Fowler, L. M. Mofenson, F. Mmiro, and J. B. Jackson. 2001. Selection and fading of resistance mutations in women and infants receiving nevirapine to prevent HIV-1 vertical transmission (HIVNET012). AIDS 15:1951-1957.
13. Fazely, F., W. A. Haseltine, R. F. Rodger, and R. M. Ruprecht. 1991. Postexposure chemoprophylaxis with ZDV or ZDV combined with interferon-a: failure after inoculating rhesus monkeys with a high dose of SIV. J. Acquir. Immune Defic. Syndr. 4:1093-1097.
14. Gaillard, P., M.-G. Fowler, F. Dabis, H. Coovadia, C. van der Horst, K. Van Rompay, A. Ruff, T. Taha, T. Thomas, I. de Vicenzi, M.-L. Newell, and for the Ghent IAS Working Group on HIV in Women and Children. 2004. Use of antiretroviral drugs to prevent HIV-1 transmission through breastfeeding: from animal studies to randomized clinical trials. J. Acquired Immune Defic. Syndr. 35:178-187.
15. Garcia-Lerma, J. G., R. A. Otten, S. H. Qari, E. Jackson, M. E. Cong, S. Masciotra, W. Luo, C. Kim, D. R. Adams, M. Monsour, J. Lipscomb, J. A. Johnson, D. Delinsky, R. F. Schinazi, R. Janssen, T. M. Folks, and W. Heneine. 2008. Prevention of rectal SHIV transmission in macaques by daily or intermittent prophylaxis with emtricitabine and tenofovir. PLoS Med. 5:e28.
16. Grob, P. M., Y. Cao, E. Muchmore, D. D. Ho, S. Norris, J. W. Pav, C.-K. Shih, and J. Adams. 1997. Prophylaxis against HIV-1 infection in chimpanzees by nevirapine, a nonnucleoside inhibitor of reverse transcriptase. Nature Med. 3:665-670.
17. Guay, L. A., P. Musoke, T. Fleming, D. Bagenda, M. Allen, C. Nakabiito, J. Sherman, P. Bakaki, C. Ducar, M. Deseyve, L. Emel, M. Mirochnick, M. G. Fowler, L. Mofenson, P. Miotti, K. Dransfield, D. Bray, F. Mmiro, and J. B. Jackson. 1999. Intrapartum and neonatal single-dose nevirapine compared with zidovudine for prevention of mother-to-child transmission of HIV-1 in Kampala, Uganda: HIVNET 012 randomized trial. Lancet 354:795-802.
18. Hirt, D., S. Urien, D. K. Ekouevi, E. Rey, E. Arrive, S. Blanche, C. Amani-Bosse, E. Nerrienet, G. Gray, M. Kone, S. K. Leang, J. McIntyre, F. Dabis, and J. M. Treluyer. 2009. Population pharmacokinetics of tenofovir in HIV-1-infected pregnant women and their neonates (ANRS 12109). Clin. Pharmacol. Ther. 85:182-9.
19. Lundgren, B., D. Bottiger, E. Ljungdahl-Ståhle, E. Norrby, L. Ståhle, B. Wahren, and B. Öberg. 1991. Antiviral effects of 3′-fluorothymidine and 3′-azidothymidine in cynomolgus monkeys infected with simian immunodeficiency virus. J. Acquir. Immune Defic. Syndr. 4:489-498.
20. McClure, H. M., D. C. Anderson, A. A. Ansari, P. N. Fultz, S. A. Klumpp, and R. F. Schinazi. 1990. Nonhuman primate models for evaluation of AIDS therapy. Ann. N. Y. Acad. Sci. 616:287-298.
21. Mori, K., Y. Yasumoti, S. Sawada, F. Villinger, K. Sugama, B. Rosenwirth, J. L. Heeney, K. Überla, S. Yamazaki, A. A. Ansari, and H. Rübsammen-Waigmann. 2000. Suppression of acute viremia by short-term postexposure prophylaxis of simian/human immunodeficiency virus SHIV-RT-infected monkeys with a novel reverse transcriptase inhibitor (GW420867) allows for development of potent antiviral immune responses resulting in efficient containment of infection. J. Virol. 74:5747-5753.
22. Otten, R. A., D. K. Smith, D. R. Adams, J. K. Pullium, E. Jackson, C. N. Kim, H. Jaffe, R. Janssen, S. Butera, and T. M. Folks. 2000. Efficacy of postexposure prophylaxis after intravaginal exposure of pig-tailed macaques to a human-derived retrovirus (human immunodeficiency virus type 2). J Virol 74:9771-5.
23. PrEP Watch, http://www.prepwatch.org/
24. Subbarao, S., R. A. Otten, A. Ramos, C. Kim, E. Jackson, M. Monsour, D. R. Adams, S. Bashirian, J. Johnson, V. Soriano, A. Rendon, M. G. Hudgens, S. Butera, R. Janssen, L. Paxton, A. E. Greenberg, and T. M. Folks. 2006. Chemoprophylaxis with Tenofovir Disoproxil Fumarate Provided Partial Protection against Infection with Simian Human Immunodeficiency Virus in Macaques Given Multiple Virus Challenges. J. Infect. Dis. 194:904-11.
25. Tsai, C.-C., K. E. Follis, A. Sabo, R. F. Grant, C. Bartz, R. E. Nolte, R. E. Benveniste, and N. Bischofberger. 1994. Preexposure prophylaxis with 9-(-2-phosphonylmethoxyethyl)adenine against simian immunodeficiency virus infection in macaques. J. Infect. Dis. 169:260-266.
26. Tsai, C.-C., K. E. Follis, T. W. Beck, A. Sabo, R. F. Grant, N. Bischofberger, and R. E. Benveniste. 1995. Prevention of simian immunodeficiency virus infection in macaques by 9-(2-phosphonylmethoxypropyl)adenine (PMPA). Science 270:1197-1199.
27. Tsai, C.-C., P. Emau, K. E. Follis, T. W. Beck, R. E. Benveniste, N. Bischofberger, J. D. Lifson, and W. R. Morton. 1998. Effectiveness of postinoculation (R)-9-(2-phosphonylmethoxypropyl)adenine treatment for prevention of persistent simian immunodeficiency virus SIVmne infection depends critically on timing of initiation and duration of treatment. J. Virol. 72:4265-4273.
28. Uberla, K., C. Stahl-Hennig, D. Böttiger, K. Mätz-Rensing, F. J. Kaup, J. Li, W. A. Haseltine, B. Fleckenstein, G. Hunsmann, B. Öberg, and J. Sodroski. 1995. Animal model for the therapy of acquired immunodefiency syndrome with reverse transcriptase inhibitors. Proc. Natl. Acad. Sci. U.S.A. 92:8210-8214.
29. Van Rompay, K. K. A., M. L. Marthas, R. A. Ramos, C. P. Mandell, E. K. McGowan, S. M. Joye, and N. C. Pedersen. 1992. Simian immunodeficiency virus (SIV) infection of infant rhesus macaques as a model to test antiretroviral drug prophylaxis and therapy: oral 3′-azido-3′-deoxythymidine prevents SIV infection. Antimicrob. Agents Chemother. 36:2381-2386.
30. Van Rompay, K. K. A., C. J. Berardi, N. L. Aguirre, N. Bischofberger, P. S. Lietman, N. C. Pedersen, and M. L. Marthas. 1998. Two doses of PMPA protect newborn macaques against oral simian immunodeficiency virus infection. AIDS 12:F79-F83.
31. Van Rompay, K. K. A., M. L. Marthas, J. D. Lifson, C. J. Berardi, G. M. Vasquez, E. Agatep, Z. A. Dehqanzada, K. C. Cundy, N. Bischofberger, and N. C. Pedersen. 1998. Administration of 9-[2-(phosphonomethoxy)propyl]adenine (PMPA) for prevention of perinatal simian immunodeficiency virus infection in rhesus macaques. AIDS Res. Hum. Retroviruses 14:761-773.
32. Van Rompay, K. K. A., M. B. McChesney, N. L. Aguirre, K. A. Schmidt, N. Bischofberger, and M. L. Marthas. 2001. Two low doses of tenofovir protect newborn macaques against oral simian immunodeficiency virus infection. J. Infect. Dis. 184:429-438.
33. Van Rompay, K. K. A. 2005. Antiretroviral drug studies in non-human primates: a valid animal model for innovative drug efficacy and pathogenesis studies. AIDS Reviews 7:67-83.
34. Van Rompay, K. K. A., B. P. Kearney, J. J. Sexton, R. Colón, J. R. Lawson, E. J. Blackwood, W. A. Lee, N. Bischofberger, and M. L. Marthas. 2006. Evaluation of oral tenofovir disoproxyl fumarate and topical tenofovir GS-7340 to protect infant macaques against repeated oral challenges with virulent simian immunodeficiency virus. J. Acquir. Immune Defic. Syndr. 43:6-14.
35. Veazey, R. S., M. S. Springer, P. A. Marx, J. Dufour, P. J. Klasse, and J. P. Moore. 2005. Protection of macaques from vaginal SHIV challenge by an orally delivered CCR5 inhibitor. Nat Med.
36. Wyand, M. S. 1992. The use of SIV-infected rhesus monkeys for the preclinical evaluation of AIDS drugs and vaccines. AIDS Res. Hum. Retrovir. 8:349-356.
37. García-Lerma J. G., Otten R. A., Qari S. H., Jackson E., Cong M. E., Masciotra S., Luo W., Kim C., Adams D. R., Monsour M., Lipscomb J., Johnson J. A., Delinsky D., Schinazi R. F., Janssen R , Folks T. M., Heneine W. Prevention of rectal SHIV transmission in macaques by daily or intermittent prophylaxis with emtricitabine and tenofovir. PLoS Med. 2008 Feb;5(2):e28

 

Animal research openness in action – from Cambridge to Florida

Last week we published an article calling on all involved in animal research to speak up for science as animal rights activists held their annual World Week for Animals in Laboratories (WWAIL), writing:

This year, if your university or facility is among those that attract attention during WWAIL, we ask that you join in the conversation by providing protestors, public, and media your own voice.  Whether it is via banners, websites, or talking with reporters– speak up for science and for public interests in advancing scientific understanding and medical progress. Although it may not matter to those committed to an absolutist agenda, it can matter to those who are interested in building a dialogue based in fact and serious consideration of the complex issues that surround public interests in the future of science, health, and medicine.”

The past few days have seen several great examples of just the sort of engagement with the public that we had in mind, including videos form two top universities in the UK that take viewers inside their animal research facilities.

The first comes from the University of Cambridge, who have published a video entitled “Fighting cancer: Animal research at Cambridge”, which focuses on how animals used in research are cared for and how the University implements the principles of the 3Rs. It includes interviews with Professor Gerard Evans of the Department of Biochemistry, who uses mice in studies of lung and pancreatic cancers, and Dr Meritxell Hutch of the Gurdon Institute, who has developed 3D liver cell culture models that she uses to reduce the number of mice required for her studies of tissue repair and regeneration, as well as with members of staff as they care for the animals.

The second example is another video, this time from Imperial College London, which also show how research staff care for the animals used in research, and features an interview with Professor of Rheumatology Matthew Pickering, who studies the role of complement proteins in liver damage in mice.

For the third example we cross the Atlantic to South Florida, where animal rights activists are trying to close down several facilities in Hendry County  that are breeding monkeys for medical research, a service that is hugely important to biomedical research. One of the companies being targeted by the animal rights campaigns is Primate Products, so we were delighted to see Dr. Jeff Rowell, a veterinarian and President of Primate Products, speak up about the vital work they do in an interview with journalist Amy Williams of local news outlet News-Press.com.

Primate products

During the interview Dr. Rowell discusses how the work of Primate Products is misrepresented by dishonest animal rights campaigns, including the inaccurate and malicious allegations made by the group Stop Animal Exploitation Now (SAEN) in 2010. As we discussed in a post at the time, these allegations were based on the deliberate misrepresentation of photos taken during veterinary care of injuries several macaques received in fighting with other macaques when housed in social groups (a normal though infrequent behaviour in the species in the wild and in captivity).

The News-Press.com article also shows that there is still a lot of work to be done to improve openness in animal research, as the three other companies that are breeding monkeys for research in Hendry County refused to speak with the Amy Williams, a shame considering that it was their decision to base themselves in the county that triggered the current animal rights campaign. While they are justifiably nervous of speaking with the press (some journalists and publications are arguably beyond redemption) the truth is that the “No comment” approach works for no-one apart from those who oppose animal research. In speaking at length with Amy Williams, Jeff Rowell has provided an excellent example that his colleagues in Hendry County would do well to follow.

The initiatives we have seen from the University of Cambridge, Imperial College London, and Primate Products over the past few days are extremely welcome, and we applaud them for their efforts. Nonetheless, we acknowledge that the future of medical science will never really be secure until they are the norm rather than the exception.

Before we conclude, it’s worth noting that it’s not just in the US and UK that researchers are beginning to realise the importance of openness in animal research to counter misleading antivivisectionist propaganda. In Italy Prof. Roberto Caminiti, a leading neurophysiologist at the University La Sapienza in Rome whose work is currently being targeted by animal rights activists, was interviewed recently for an excellent video produced by Pro-Test Italia, in which he discusses his primate research and how it is regulated.

Speaking of Research

American Society of Primatologists’ statement of support for NIH primate research

The nation’s largest primatological scientific society, the American Society of Primalogists (ASP), has posted a strong statement sent January 21 in support for the scientist and research under attack by PETA.  The statement can be found on ASP’s website: https://www.asp.org/index.cfm

ASP home page Jan 2015

In its entirety, the letter reads:

“Members of the Board of Directors of the American Society of Primatologists would like to add our comments to the discussion of the validity and effectiveness of non-human primate research as it pertains to human behavior and medicine. Non-human primate research (on monkeys and apes) has had widespread effect on improving the diagnosis and treatment of many adult and childhood diseases. Studies that have employed the judicious use of non-human primates as models for human illness have improved our understanding of such disorders as autism, childhood leukemia, cerebral palsy, and mental health.1 The long-term research of one scientist, Dr. Stephen Suomi, has been called into question as a result of inaccurate, misguided and inflammatory media accounts. Our comments will address Dr. Suomi’s work and the value of non-human primates in understanding human biology, illness and behavior.

Dr. Suomi’s research has focused on the influence of variable environments and genetics on infant development, and by extension variation in adult behavior2. He and his colleagues found that early changes in the degree of attachment between mother and infant have real biological, not only behavioral influences on adult social behavior3. If this finding seems intuitive, it is evidence that the benefits of research have permeated not only the scientific, but also mainstream media4 and literature. Infant subjects are either mother-reared or reared in same-aged groups of monkeys. Infants may undergo temporary isolation during the study5 to facilitate comparison among groups that are reared differently. The goal of much of this research is to mimic separation that every social animal, including humans, undergo during their lifetimes and to understand why individuals respond differently to separation. One such research focus is the development of risk factors leading to mental illness in humans.

The American Society of Primatologists supports research on non-human primates that is carefully designed and employs rigorous research protocols. Dr. Suomi’s research and consistent funding by the NIH attests to his adherence to prescribed protocols and regulations.

Before research can begin, proposals are thoroughly vetted by both their institutional ethical oversight board (in the United States these are called Institutional Animal Care and Use Committees or IACUCs) and by the review boards of granting agencies (e.g., NIH, NIMH, NSF). This very extensive process requires prospective researchers to respond to questions such as those raised in your letter, e.g., your concern about redundant research. Per both the Animal Welfare Act and Regulations (AWARs) and the Public Health Service Policy on the Humane Care and Use of Laboratory Animals (PHS Policy), research funded by federal and state governments, as well as private foundations, must demonstrate that the project they propose will advance knowledge in the field, be relevant to human biology or behavior, and will not duplicate the efforts of previous research. The number of animals used in experiments must also be justified as well as the conditions in which the animals are housed, the duration of the project, and the protocols implemented during experiments. The scientists employed by the NIH have been leaders in the development of safe, effective, and reliable research protocols whether the research is done on mice or monkeys.

Because of the close genetic relationship between humans and non-human primates, monkeys are important models for studying particular biological phenomena, including the research conduct by Dr. Suomi. Nevertheless, non-human primates are rare in laboratory populations making up < 1% of the laboratory animals used in research (Government statistics from 2010, cited in Phillips et al., 20146). Furthermore, species are carefully matched to proposed studies.

We appreciate your attention to this matter, and ask that you please send us a response letting us know the charge to the NIH Bioethics Review Board.

Respectfully submitted,
Marilyn A. Norconk, President; Justin A. McNulty, Executive Secretary; Kimberley A. Phillips,  President-Elect; Corinna N. Ross, Treasurer; Karen L. Bales, Past-President