Saliva May Help Diagnose PTSD in Veterans
A recent study finds that former soldiers with post traumatic stress disorders have a certain set of bacteria in their saliva, a distinct signature that is believed to be the first biological marker for PTSD.
As a bioinformatician and young veteran, Guy Shapira welcomed the opportunity to help with conducting a study to determine if saliva can reveal if war veterans have post-traumatic stress disorder, or PTSD.
The research team, which drew mostly from Tel Aviv University’s Sackler Faculty of Medicine and Sagol School of Neuroscience, collected saliva samples from approximately 200 veterans who suffered psychological trauma stemming from the years they spent fighting in the First Lebanon War in 1982. The researchers also characterized the participants’ psychological, social and medical conditions, including a detailed analysis of their microbiomes.
They found that the former soldiers with PTSD have a certain set of bacteria in their saliva, a distinct microbiotic signature that is believed to be the first biological marker for PTSD. The finding suggests that, in the future, saliva tests could be used to help identify this disorder. As of now, PTSD is often challenging to diagnose.
Shapira, a Ph.D. student at Tel Aviv University, was responsible for examining genetic and health-related data of the veterans who participated – information that had been compiled steadily over four decades. The veterans provided this data voluntarily, Shapira says, at least partly because the study carries important implications for their own psychological health.
The research was led by Illana Gozes, professor emerita of clinical biochemistry. “We looked at the bacteria in their blood and their saliva,” Gozes explains. To discover the microbial signatures, they analyzed the biometric data for each soldier individually and as a group. Comparing the results of the participants’ microbial distribution to the results of their psychological examinations and their responses to personal welfare questionnaires, the researchers learned that veterans with PTSD – and, more generally, those with significant mental health issues – have the same bacterial content in their saliva.
“Having empirical metrics to assess whether or not someone has PTSD can help veterans who make their case to the Army to get reparations,” Shapira says.
More research is required to support this finding, published in July in Nature’s prestigious Molecular Psychiatry, but it could have important implications for identifying people with PTSD. Currently, it can be diagnosed only through psychological and behavioral symptoms such as flashbacks, nightmares, sleep disorders, increased irritability and physical aggressiveness. Veterans sometimes don’t report these symptoms to health providers or realize they’re related to the trauma they experienced during combat.
The researchers also identified a correlation that indicates people with a higher level of education show a lower occurrence of the microbiotic signature linked to PTSD, while people who experienced greater exposure to air pollution show a higher occurrence of this signature. That confirms their finding that the veterans’ health is dependent on their individual biology combined with the conditions of their environment.
“Thanks to this study, it may be possible in the future to use objective molecular and biological characteristics to distinguish PTSD sufferers, taking into account environmental influences,” Gozes said in an article in Israel21c. “We hope that this new discovery and the microbial signatures described in this study might promote easier diagnosis of post-traumatic stress in soldiers so they can receive appropriate treatment.”
Gozes added that roughly a third of the subjects in their study hadn’t been diagnosed with PTSD previously. That meant they had never received any support from Israel’s Ministry of Defense or other officials for treatment and reparations, the payments to compensate for injuries sustained during war.
Shapira’s motivation to participate in this study is personal as well as professional: in addition to being veteran himself, his father served in the First Lebanon War. “Fortunately, he did not develop any PTSD, despite being shot in the foot...some of his friends died, so it wasn’t easy on him,” says Shapira.
“Having empirical metrics to assess whether or not someone has PTSD can help veterans who make their case to the Army to get reparations,” Shapira says. “It is a very difficult and demanding process, so the more empirical metrics we have to assess PTSD, the less people will have to suffer in these committees and unending examinations that are mostly pitched against the veterans because the state is trying to avoid spending too much money.”
In this week's Friday Five, research on a "smart" bandage for wounds, a breakthrough in fighting inflammation, the pros and cons of a new drug for Alzheimer's, benefits of the Mediterranean diet with a twist, and we've learned to recycle a plastic that was un-recyclable.
The Friday Five covers five stories in research that you may have missed this week. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend.
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Here are the promising studies covered in this week's Friday Five:
- Research on a "smart" bandage for wounds
- A breakthrough in fighting inflammation
- The pros and cons of a new drug for Alzheimer's
- Benefits of the Mediterranean diet - with a twist
- How to recycle a plastic that was un-recyclable
Sexually Transmitted Infections are on the rise. This drug could stop them.
Cases of gonorrhea, chlamydia and syphilis soared last year, but researchers are finding that a drug known as doxy seems to reduce the number of infections.
Sexually transmitted infections (STIs) are surging across the U.S. to 2.5 million cases in 2021 according to preliminary data from the CDC. A new prevention and treatment strategy now in clinical trials may provide a way to get a handle on them.
It's easy to overlook the soaring rates of gonorrhea, chlamydia, and syphilis because most of those infections have few or no symptoms and can be identified only through testing. But left untreated, they can lead to serious damage to nerves and tissue, resulting in infertility, blindness, and dementia. Infants developing in utero are particularly vulnerable.
Covid-19 played havoc with regular medical treatment and preventive care for many health problems, including STIs. After formal lockdowns ended, many people gradually became more socially engaged, with increases in sexual activity, and may have prioritized these activities over getting back in touch with their doctors.
A second blow to controlling STIs is that family planning clinics are closing left and right because of the Dobbs decision and legislation in many states that curtailed access to an abortion. Discussion has focused on abortion, but those same clinics also play a vital role in the diagnosis and treatment of STIs.
Routine public health is the neglected stepchild of medicine. It is called upon in times of crisis but as that crisis resolves, funding dries up. Labs have atrophied and personnel have been redirected to Covid, “so access to routine screening for STIs has been decimated,” says Jennifer Mahn, director of sexual and clinical health with the National Coalition of STD Directors.
A preview of what we likely are facing comes from Iowa. In 2017, the state legislature restricted funding to family health clinics in four counties, which closed their doors. A year later the statewide rate of gonorrhea skyrocketed from 83 to 153.7 cases per 100,000 people. “Iowa counties with clinic closures had a significantly larger increase,” according to a study published in JAMA. That scenario likely is playing out in countless other regions where access to sexual health care is shrinking; it will be many months before we have the data to know for sure.
A decades-old antibiotic finds a new purpose
Using drugs to protect against HIV, either as post exposure prophylaxis (PEP) or pre-exposure prophylaxis (PrEP), has proven to be quite successful. Researchers wondered if the same approach might be applied to other STIs. They focused on doxycycline, or doxy for short. One of the most commonly prescribed antibiotics in the U.S., it’s a member of the tetracycline family that has been on the market since 1967. It is so safe that it’s used to treat acne.
Two small studies using doxy suggested that it could work to prevent STIs. A handful of clinical trials by different researchers and funding sources set out to generate the additional evidence needed to prove their hypothesis and change the standard of care.
Senior researcher Victor Omollo, with the Kenya Medical Research Institute, noted, “These are prevention interventions that women can control on their own without having to seek or get consent from another person,” as is the case with condom use.
The first with results is the DoxyPEP study, conducted at two sexual health clinics in San Francisco and Seattle. It drew from a mix of transgender women and men who have sex with men, who had at least one diagnosed STI over the last year. The researchers divided the participants into two groups: one with people who were already HIV-positive and engaged in care, while the other group consisted of people who were on PrEP to prevent infection with HIV. For the active part of the study, a subset of the participants received doxy, and the rest of the participants did not.
The researchers intentionally chose to do the study in a population at the highest risk of having STIs, who were very health oriented, and “who were getting screened every three months or so as part of their PrEP program or their HIV care program,” says Connie Celum, a senior researcher at the University of Washington on the study.
Each member of the active group was given a supply of doxy and asked to take two pills within 72 hours of having sex where a condom was not used. The study was supposed to run for two years but, in May, it stopped halfway through, when a safety monitoring board looked at the data and recommended that it would be unethical to continue depriving the control group of the drug’s benefits.
Celum presented these preliminary results from the DoxyPEP study in July at the International AIDS Conference in Montreal. “We saw about a 56 percent reduction in gonorrhea, about 80 percent reduction in chlamydia and syphilis, so very significant reductions, and this is on a per quarter basis,” she told a later webinar.
In Kenya, another study is following a group of cisgender women who are taking the same two-pill regimen to prevent HIV, and the data from this research should become available in 2023. Senior researcher Victor Omollo, with the Kenya Medical Research Institute, noted that “these are prevention interventions that women can control on their own without having to seek or get consent from another person,” as is the case with condom use, another effective prevention tool.
Antibiotic resistance
Antibiotic resistance is a potentially big concern. About 25 percent of gonorrhea strains circulating in the U.S. are resistant to the tetracycline class of drugs, including doxy; rates are higher elsewhere. But resistance often is a matter of degree and can be overcome with a larger or longer dose of the drug, or perhaps with a switch to another drug or a two-drug combination.
Research has shown that an established bacterial infection is more difficult to treat because it is part of a biofilm, which can leave only a small portion or perhaps none of the cell surface exposed to a drug. But a new infection, even one where the bacteria is resistant to a drug, might still be vulnerable to that drug if it's used before the bacterial biofilm can be established. Preliminary data suggests that may be the case with doxyPEP and drug resistant gonorrhea; some but not all new drug resistant infections might be thwarted if they’re treated early enough.
“There are some tradeoffs” to these interventions, Celum says, and people may disagree on the cost of increased resistance balanced against the benefits of treating the STIs and reducing their spread within the community.
Resistance does not seem to be an issue yet for chlamydia and syphilis even though doxy has been a recommended treatment for decades, but a remaining question is whether broader use of doxy will directly worsen antibiotic resistance in gonorrhea, or promote it in other STIs. And how will it affect the gut microbiome?
In addition, Celum notes that we need to understand whether doxy will generate mutations in other bacteria that might contribute to drug resistance for gonorrhea, chlamydia or syphilis. The studies underway aim to provide data to answer these questions.
“There are some tradeoffs” to these interventions, Celum says, and people may disagree on the cost of increased resistance balanced against the benefits of treating the STIs and reducing their spread within the community. That might affect doctors' willingness to prescribe the drug.
Turning research into action
The CDC makes policy recommendations for prevention services such as taking doxy, requiring some and leaving others optional. Celum says the CDC will be reviewing information from her trial at a meeting in December, but probably will wait until that study is published before making recommendations, likely in 2023. The San Francisco Department of Public Health issued its own guidance on October 20th and anecdotally, some doctors around the country are beginning to issue prescriptions for doxy to select patients.
About half of new STIs occur in young people ages 15 to 24, a group that is least likely to regularly see a doctor. And sexual health remains a great taboo for many people who don't want such information on their health record for prying parents, employers or neighbors to find out.
“People will go out of their way and travel extensive distances just to avoid that,” says Mahn, the National Coalition director. “People identify locations where they feel safe, where they feel welcome, where they don't feel judged,” Mahn explains, such as community and family planning clinics. They understand those issues and have fees that vary depending on a person’s ability to pay.
Given that these clinics already are understaffed and underfunded, they will be hard pressed to expand services covering the labor intensive testing and monitoring of a doxyPEP regimen. Sexual health clinics don't even have a separate line item in the federal budget for health. That is something the National Association of STI Directors is pushing for in D.C.
DoxyPEP isn't a panacea, and it isn't for everyone. “We really want to try to reach that population who is most likely going to have an STI in the next year,” says Celum, “Because that's where you are going to have the biggest impact.”