Chronic inflammatory bowel disease (IBD), such as Crohn’s disease and ulcerative colitis, is on the rise worldwide, and current medications have problematic side effects. In the journal Angewandte Chemie, researchers report a new method of treatment, based on nanoparticles which trigger anti-inflammatory effects in the diseased sites in the intestine.
Stomach cramps and severe diarrhoea, often accompanied by significant weight loss, are some of the symptoms repeatedly suffered by patients with IBD, often for weeks at a time. The causes of this condition remain unclear but seem to involve a malfunction of the immune system. A cure is not yet in sight. Current treatments aim to reduce symptoms with anti-inflammatory medications, such as 5-aminosalicylic acid (5-ASA), corticosteroids, and immunomodulators. Their long-term use is not recommended because of their severe side effects, such as a high risk of infection resulting from immunosuppression. A team led by Hee-Seung Lee and Sangyong Jon at the Korea Advanced Institute of Science and Technology (KAIST) has now developed an innovative approach for a medication that can be taken orally and targets the inflamed sites in the gastrointestinal tract, minimizing systemic effects.
The starting point of their approach was the glycocalyx, a carbohydrate-rich layer that coats the cells on the surface of the intestine. Beneficial gut bacteria, which have their own matching glycocalyx, attach to this coating. With diseases from the IBD family, the glycocalyx carbohydrate patterns of inflamed intestinal regions are so altered that pathogenic bacteria can attach and enter the mucous membrane.
The team developed nanoparticles that mimic the glycocalyx pattern. Starting with the five sugar monomers most commonly found in nature, they produced a collection (“substance library”) of different polymer chains that have one, two, three, four, or five of these sugars in random order and composition as side chains. These polymer chains aggregate into nanoparticles. They also attached bilirubin molecules. Bilirubin is a bile pigment that is an antioxidant naturally produced by the body and it has an anti-inflammatory effect.
When administered orally to mice with IBD, some versions of these nanoparticles reduced symptoms significantly better than the drug 5-ASA. Nanoparticles with mannose and N-acetylglucosamine were the most effective. These two sugars increase uptake of the nanoparticles by activated macrophages in the inflamed intestine, and bilirubin very efficiently inhibits the inflammatory activity of these immune cells. The concentration of certain inflammatory cytokines is significantly reduced, the production of anti-inflammatory factors is stimulated, and oxidative stress is reduced. The immunosuppressive effect is limited to the inflamed areas of the intestine, minimising unfavourable systemic side effects.
A pair of new studies explains why babies get so many common respiratory infections and identifies a specialised cluster of immune cells found only in babies that help them better cope with new pathogens, helping explain why they were less vulnerable to COVID infection.
“We know little about how the immune system develops throughout life, and most of what we know about immune system development in children comes from animal studies,” says lead researcher Donna Farber, PhD, an expert in immune system development at Columbia University. “But mice develop much more quickly than humans and their immune systems are a bit different than ours.”
Using a trove of tissue samples from deceased paediatric organ donors, Farber’s team was able to pinpoint aspects of immune system development that distinguish babies from adults.
Immune cells in lungs and gut take time to mature
One study, published in Immunity, found that memory T cells, formed after first exposure to a pathogen, accumulate rapidly in the lungs and intestines through age three and more gradually in blood and lymph tissues. These cells enable older children and adults to mount an immediate and specific immune response during the next encounter with a pathogen.
But there’s a hitch.
“We found that memory T cells in young children are not functionally mature and only begin to have the capacity for protective immunity at around ages four to six years,” Farber says. “This explains why babies and young children are more vulnerable to recurrent respiratory infections and other infectious diseases compared with adults.”
The findings also may explain why introducing foods to children during the first year of life could prevent severe food allergies. “Early memory T cells are more tolerant than mature memory cells, so they’re not going to create an immune response against new foods,” Farber says.
‘Secret weapon’ protects babies from new pathogens
But while babies are highly susceptible to recurrent infections, a second study, published in Nature Immunology, found that babies have a unique way of coping with new pathogens. The researchers found clusters of antibody-producing B cells surrounded by T cells in the infants’ lungs. This bronchus-associated lymphoid tissue, or BALT, is formed between six and 12 months of age and disappears after age three.
“BALT enables the lung to make antibodies to respiratory pathogens well before T cell memory has developed but fall apart in later childhood when they are no longer needed,” says Farber. “This mechanism helps young children respond to the many different respiratory pathogens they encounter early in life.”
It also may explain why young children are more resilient to new respiratory infections compared to adults, as seen with SARS-CoV-2.
“With SARS-CoV-2, a virus no one had ever encountered before, we saw that people in their 50s and 60s were very susceptible to severe COVID, but most kids exposed to SARS-CoV-2 were fine, and many didn’t even have symptoms,” Farber says. “That told us that the babies and young children must have some adaptations to respond to new pathogens that adults don’t have.”
BALT also may be a reason why some children develop chronic asthma and allergies. “It’s possible that these diseases may be caused in part by the abnormal persistence of BALT well into childhood, which could trigger an overreaction to certain antigens,” says Farber.
Farber adds that the study may provide clues about why early trials of intranasal COVID vaccines have not shown promise in adults, whereas intranasal influenza vaccine tends to work better in children. “It could be that this type of vaccine works better in children because they have BALT structures that can initiate new antibodies in the lungs.”
“BALT provides some protection but clearly does not protect young children from everything,” Farber continues. “We have to remember that before vaccines, a third of children died of infectious diseases during infancy. So childhood vaccines are really important for protecting us.”
Research team led by Joshua Pearce has developed a new 3-D printed, completely open-source autoinjector for a tenth of the cost of a commercially purchased product. (Photo by Anjutha Selvaraj)
A new study published in PLOS One describes the development of a spring-driven autoinjector for the delivery of insulin and other medications. This device, made from a combination of 3D-printed and commercially available parts, could cost less than $7 to make while a store-bought version is closer to $70.
Sir Frederick Banting was an inspiration for a new open source self-administering drug delivery device. Long before open source was an option or even a concept, the now-celebrated former University of Western Ontario lecturer refused to patent insulin because he wanted it to be inexpensive and widely available for the betterment of all.
A century after Banting won the Nobel Prize for his discovery, Western researchers led by engineering and Ivey Business School professor Joshua Pearce has developed a new 3D printed, completely open-source autoinjector – a device designed to deliver a single dose of medicine – for a tenth of the cost of a commercially purchased product.
“I think of this device, like so much of what we’re doing here at Western, very much as following the golden rule: do unto others as you would have them do unto you,” said Pearce. “It makes the world slightly better to have an open-source version of an autoinjector, especially for people who don’t have access or the financial means to purchase a proprietary one.”
Autoinjectors are used all over the world by health care practitioners, patients and parents (for children under 12) to inject insulin into people with diabetes. Other chronic conditions such as psoriasis, multiple sclerosis and rheumatoid arthritis can also be treated using an autoinjector. The device is also essential during emergency conditions for migraine, anaphylaxis and status epilepticus patients, as well.
Pearce, along with research assistant Anjutha Selvaraj and post-doctoral associate Apoorv Kulkarni, have created the new open-source autoinjector to make the device – considered more reliable and easier to operate than a simple syringe for self-administering medications into the body – an equitable alternative to the more expensive options.
Studies show self-administration of medications by patients improves compliance and comfort and empowers patients as they are actively involved in their personal care. It also allows patients to avoid time-consuming and costly visits to the hospital, which is a bonus for overburdened health care systems.
And, as with all open-source hardware, there is money to be made as the digitally replicable device enables low-cost distributed manufacturing. All materials, designs and assembly instructions are also detailed in the new study, and the effectiveness of the autoinjector is tested against the current standard (ISO 11608-1:2022) for needle-based injection systems. It is released with an open source hardware license. Companies wishing to commercialise the device will still need to meet their own local regulatory requirements.
“Does this design make it possible for other people to commercialise it anywhere in the world? Yes, it does,” said Pearce. “But more importantly, it means we can really target isolated communities, whether they’re in northern Canada, Africa or anywhere in else in the world, and improve health care access for everyone.”
In what is likely one of the largest treatment rollouts in South African history, well over four million people living with HIV have started taking the antiretroviral dolutegravir since its introduction around four years ago. Now, according to a recent study published in the Lancet medical journal, use of dolutegravir in South Africa is associated with more people staying on treatment and higher rates of viral suppression.
The use of a three-in-one combination of the antiretroviral drugs tenofovir, lamivudine and dolutegravir (TLD for short) for the treatment of HIV was first recommended by the World Health Organization (WHO) in 2018. A year later it was recommended in the South African treatment guidelines as first line treatment for HIV and a three-year tender was awarded. Since then, dolutegravir has largely replaced another antiretroviral called efavirenz.
Today, TLD is the recommended treatment option for most people living with HIV in the country. The 2023 National antiretroviral (ARV) guidelines also include recommendations for the use of child-friendly formulations of dolutegravir and dolutegravir containing regimens in kids. Spotlight reported on these here.
Around 4.7m people in SA taking dolutegravir
According to Foster Mohale, spokesperson for the National Department of Health, in 2019 the HIV clinical guidelines were revised to include a fixed combination dose of TLD “for all eligible people for use as the first line regimen.”
Based on this, the department set a goal that 90% of those eligible for it should receive TLD as a first line regimen. In terms of meeting this goal, Mohale says that by March 2023, just over four million (4 127 427) people were on TLD. Additionally, about 650 000 (653 884) people were on other dolutegravir based regimens. Altogether, there are thus now over 4.7 million people in the country on treatment combinations that include dolutegravir.
“Based on the March 2023 data, 90% of clients on first line regimen were on TLD. However, performance varies by province,” he says.
Of the total number of people on ART in the public health sector, 75.8% are on TLD, according to Mohale.
Trends in the roll out
While on paper the country’s transition from efavirenz to dolutegravir-based regimens seems to have been smooth, the reality on the ground has been more complex. A study published in the Lancet earlier this year looked at real-world rollout data from 2019 to 2022. The study was conducted in 59 clinics across the country and collected data from two cohorts-one cohort were first time initiators of ART and the other were transitioning from regimens that did not include dolutegravir to ones that did.
In the initiator cohort, just over 45 000 people were initiated on ART between December 2019 and February 2022. Of those, 68.9% were initiated on dolutegravir-based regimens, 31.1% on efavirenz-based regimens, and 0.1% on nevirapine-based regimens.
Those initiated on dolutegravir-based regimens were more likely to still be on treatment a year later and were also more likely to be virally suppressed than those who were initiated on the other regimens.
In December 2019, in the transition cohort, just over 180 000 people were on a non-dolutegravir first line regimen. By February 2022, 67% of them had transitioned to a dolutegravir-based regimen. These people were also more likely to be retained in care at 12 months and be virologically suppressed than those who had not switched to a dolutegravir-based regimen.
“That’s good for a number of reasons. It means that the treatment’s working, people are less likely to get unwell and also, they can’t transmit the virus onto other people,” explains Dr Jienchi Dorward, one of the study authors and an academic clinical lecturer at the University of Oxford and honorary associate scientist at the Centre for the AIDS Programme of Research in South Africa (CAPRISA).
‘Bumpy transition’
Dr Yukteshwar Sookrajh, a Senior Medical Practitioner at the eThekwini Municipality Health Unit who was also involved in the study, tells Spotlight that the rollout quickly gathered momentum.
“But initially there were some issues to navigate around drug interactions; concurrent TB infection and the use of dolutegravir in women of childbearing potential,” he says. “Once those concerns were addressed, the comfort of switching to dolutegravir was increased and we find that the majority of our patients have now safely transitioned across to dolutegravir-based regimens.”
In many ways South Africa was slow in rolling out dolutegravir compared to other African countries, according to Professor Francois Venter, the head of Ezintsha at Wits University. Reasons for this, he says, include an initial concern around the safety of dolutegravir use among pregnant women, and disruption in training due to the COVID-19 pandemic.
He says that the South African Clinicians society was alerted during the COVID-19 pandemic that many patients in the public health sector had still not been transitioned to dolutegravir. An education campaign was then launched to encourage clinicians to start or switch patients to dolutegravir.
However, as it stands now the rollout of the drug in the public sector has been a huge success, despite what Venter calls a “bumpy transition”.
Initial safety concerns
One important reason to conduct the study reported in the Lancet, according to Dorward, was a safety concern regarding the use of dolutegravir by pregnant women. An earlier study conducted in Botswana called Tsepamo found a higher prevalence of neural-tube defects (a type of birth defect) associated with dolutegravir exposure at conception than with other types of antiretroviral exposure. As more data has been gathered since, it has however become clear that dolutegravir does not in fact increase the risk of neural-tube defects.
But the Tsepamo scare did impact who was initiated and transitioned onto dolutegravir in first two years of the rollout.
“The initial concerns around neural-tube defects and the use of dolutegravir in women of childbearing potential clearly hampered rollout of dolutegravir in women – and this has been clearly demonstrated in this study,” says Sookrajh.
The Lancet study found that pregnant women and non-pregnant women were less likely to be initiated on dolutegravir than men early in the rollout, with the biggest difference between women and men aged 15 to 24 years old. This difference decreased with age and by age 55 there was no difference between men and women receiving dolutegravir.
But this changed over time and by September 2021 women were as likely to get initiated on dolutegravir as men. Spotlight previously reported that the rollout was done in two stages. In the first stage men, adolescent boys, women on reliable contraception, and older women were prioritised.
Of those who started treatment during the study period, 46.9% of the pregnant women in the cohort were initiated on dolutegravir-based regimens, while 63.9% of the non-pregnant women and 82.3% of the men in the cohort were initiated on dolutegravir-based regimens.
“In both those groups [cohorts] we found that women were less likely than men to get dolutegravir, but interestingly, this was particularly in younger women,” Dorward explains. “As time went on, the difference between men and women became much less…around June to September 2021 was a time period where we found that women and men pretty much began to equally get dolutegravir.”
Dorward says the data showed an uptick in women in the study being given dolutegravir once the South African guidelines changed to reflect that there was no longer a concern around neural-tube defects. It is thus likely that the safety concern was responsible for the lower initial uptake among young women.
He adds that the messaging around this potential risk was based on the evidence available at the time and was clearly outlined in the guideline document and training for dolutegravir use, but these did not appear to adequately allay these concerns among healthcare workers.
“The risks versus benefits needed to be messaged in a more effective way such that healthcare workers were more comfortable and confident in offering dolutegravir to women,” he says. Based on this experience Sookrajh adds that in future there needs to be more engagement with “practitioners on the ground to determine what type of messaging and supportive materials are required to facilitate better understanding of guidelines at the coal face.”
Another concern for some healthcare workers has been that dolutegravir-based regimens have been associated with greater weight gain than efavirenz-based regimens. But, as argued in a recent editorial in the Southern African Journal of HIV medicine, association is not the same as causation and it may well be that efavirenz inhibits weight gain rather than dolutegravir promoting it. People living with HIV who start taking antiretroviral medicines often gain weight as their health recovers.
New guidelines should further boost uptake
Sookrajh says that the National Department of Health’s antiretroviral (ARV) 2023 guidelines will further improve the uptake of dolutegravir in the public healthcare system.
“With the April 2023 National Department of Health ARV Guidelines, we actually find that further barriers to switching to dolutegravir have been removed and dolutegravir is clearly placed as the preferred drug of choice in almost all scenarios for both first- and second-line antiretrovirals,” he says.
“I think the new [ARV] guidelines hopefully will be a big improvement for people who are on treatment, and part of that is possible because we’re using the drug that is better. You’re less likely to get resistance with dolutegravir so we’re less worried if people don’t take treatment properly that they might get drug resistance, although we still need more research to be sure about that,” Dorward says. “And it’s still very important for people to take treatment consistently to suppress the virus and maintain their own health and prevent onward transmission.”
According to Venter, there needs to be proper resistance surveillance to detect potential dolutegravir resistance.
“We can’t take for granted we’ll never have resistance [to dolutegravir]…eventually there will be the occasional patient that does have resistance, but we need proper surveillance there,” he says. “And then we need to keep an eye on things. There are still patients getting HIV…there’s still a lot of new infections…we need to make that stop…we’ve got amazing PrEP and way too few people getting it. So, we do need to start addressing that.” (PrEP, or pre-exposure prophylaxis, refers to antiretrovirals taken to prevent HIV infection.)
Venter adds that while successful in the public health sector, the uptake of dolutegravir has been extremely slow in the private health sector for reasons unknown to him.
Penicillin allergy affects up to 1 in 10 Americans yet most penicillin allergy labels are in fact incorrectly applied. In addition to limiting the choice of antibiotics to prescribe, the widespread mislabelling contributes to the growing threat of antibiotic resistance. A new procedure developed by researchers at Vanderbilt University Medical Center aims to fix that.
Some 75% of penicillin allergy labels come on by age 3 due to, for example, confusion with a viral rash. The majority of these rashes were never allergic, but the labels ‘stick’ into adulthood and carry many adverse consequences.
Many low-risk patients with a penicillin allergy were able to have their penicillin allergy label removed through a simple procedure known as “direct oral challenge” as part of a world-first multi-centre randomised control trial known as the Penicillin Allergy Clinical Decision Rule (PALACE) study, the results of which were published in JAMA Internal Medicine.
In the PALACE study, investigators randomised low-risk penicillin allergic patients to two different approaches to remove their allergy label. They either underwent the current standard of care to have skin testing followed if negative by oral challenge with a penicillin or they went straight to oral challenge (“direct oral challenge”) without preceding skin testing.
“The majority of patients labelled as penicillin allergic, more than 90%, have low-risk histories, meaning they did not have a history to suggest a severe or more recent reaction to a penicillin,” said PALACE study protocol member and Vanderbilt University Medical Center principal investigator Elizabeth Phillips, MD. “We would expect more than 95% of these patients to have negative testing and be able to take penicillin in the future.”
The study, undertaken by a team of researchers from specialised centres in North America and Australia, enrolled 382 adults who were assessed using a specialized risk assessment tool called PEN-FAST. Participants were randomly assigned to receive either a direct oral penicillin challenge or the standard approach (penicillin skin testing followed by an oral challenge). The primary goal was to determine if the direct oral penicillin challenge was no worse than the standard method of skin testing followed by oral challenge which needs to be performed in an allergist’s office.
Only one patient (0.5%) in each group experienced a positive reaction to the penicillin challenge, demonstrating that the direct oral penicillin challenge performs just as well as the standard method. Importantly, there were no significant differences in adverse events between the two groups, and no serious adverse events were reported.
The findings have wide-ranging implications for patients. By accurately identifying low-risk penicillin allergy patients, health care providers can ensure appropriate antibiotic prescriptions. Patients with a documented penicillin allergy are more likely to be prescribed alternative antibiotics, known as second-line antibiotics, which are often not as effective against certain infections and may have more side effects.
“Patients with penicillin allergy are more likely to get second-line or broader spectrum antibiotics that lead to risk of antibiotic resistance and serious infections such as antibiotic-associated diarrhoea due to Clostridioides difficile, which can spread through hospitals and become a major public health problem.” Phillips said. “In the US increasingly we also have a major problem with other antibiotic-resistant ‘superbugs’ such as multi-resistant gram-negative infections, Candida auris and even a resurgence of syphilis for which penicillin is the best treatment and the only treatment that should be used in pregnancy to prevent transmission to an unborn child.
“The evidence provided by the PALACE study will change clinical practice. Many patients in the United States do not have direct access to an allergist to provide specialised testing such as skin testing. Therefore, the ability to go to direct oral challenge with a penicillin in low-risk patients which can be carried out in any observed setting will make it easier for patients in the United States to access health care to safely and effectively remove the label of penicillin allergy,” she said.
