A patch made of stem cells from donor placentas has been used to treat fetuses in the womb with a severe form of spina bifida as part of a world-first trial. The novel approach seems to have reversed a brain complication associated with the congenital condition at least as effectively as the go-to treatment, but is expected to enable more children to walk over the long term.

The mother of one of the babies, who is now 4 years old, says she expected that her son Toby would require a wheelchair when he was diagnosed with the condition in the womb. “But Toby is healthy [and] has hit all of his milestones – he’s walking, running and jumping – and has no problems with bladder control, which is rare for people with the condition,” she says.

Spina bifida – which affects about – occurs when a baby’s spine and spinal cord do not fully develop in the womb. In the most severe form of the condition, called myelomeningocele, the spinal cord and its surrounding tissue protrude out of a gap in the vertebrae, which often impairs mobility and bowel and bladder control. The cause of spina bifida is unknown, but folic acid deficiency during pregnancy raises the risk.

One of the standard treatments involves surgery in the womb that tucks the spinal cord and the surrounding tissue back into the vertebrae, before sewing up the skin to form a tight seal. “But many children still end up unable to walk and there’s [usually] no improvement in bowel or bladder control,” says at the University of California, Davis.

This led Farmer and her colleagues to wonder if the addition of stem cells could help by promoting the growth and repair of spinal tissue. To find out, they recruited six pregnant women carrying fetuses with myelomeningocele.

By about 24 weeks’ gestation, all the fetuses had developed a common complication called hindbrain herniation, where too much fluid builds up in the skull, pushing the bottom of the brain, the cerebellum, through a hole at the skull’s base. The standard surgery often helps to reverse hindbrain herniation, but many children still have complications.

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In the latest trial, all the fetuses underwent the standard surgery but also received a patch, measuring a few centimetres long, that contained stem cells derived from donated placentas that were embedded in a matrix of sticky proteins. Surgeons placed this patch on the spine before the skin was sewn around it. “The cells secrete their magic stem cell juice,” says Farmer.

At birth, the surgery site had healed well in all of the babies, with no signs of abnormal cell growth. “A key worry was that adding stem cells in a fetus would make the cells grow like crazy, but we didn’t see that,” says Farmer. MRI scans of their brains also showed that the treatment completely reversed hindbrain herniation.

Mini-brains have been fused to resemble that of a 40-day-old fetus

By fusing different human organoids, researchers have created “mini-brains” containing most of the cell types found in fetal brains

“My personal opinion is that this will improve long-term outcomes compared to the standard approach [based on evidence from animal studies],” says at King’s College London.

The researchers hope to assess this in a trial where 35 fetuses with myelomeningocele will receive the stem-cell patch, and their outcomes will be compared against a previous study that used the conventional surgery, says Farmer.

But Shangaris says that a better comparison, which is more likely to lead to the treatment being approved, would be to compare the two approaches in a head-to-head trial that assesses their safety and efficacy on fetuses who were randomly assigned to each intervention.

Surgery is typically a last resort for people with a chronically blocked or runny nose. But in some cases, it may actually work better than the antibiotics that are routinely prescribed to treat the condition.

Chronic sinusitis affects about and occurs when the mucus-producing cavities – sinuses – around the nose become inflamed. Common symptoms include a blocked or runny nose, a reduced sense of smell and facial pain, with these persisting for more than 12 weeks. The cause of the condition is usually unclear but may involve viral infections or a change to the nose microbiome.

The first line of treatment involves anti-inflammatory nasal sprays and flushing saline solution through the nose daily. But if symptoms persist, doctors often prescribe a three-month course of the antibiotic clarithromycin. This is used for its anti-inflammatory properties rather than its bacteria-killing properties, says at the University of East Anglia in the UK.

As a last resort, people can undergo surgery to widen the sinuses and remove any benign nasal growths, or polyps, which form and worsen symptoms in of cases. Yet no prior study has directly compared surgery with antibiotics.

To fill this gap, Philpott and his colleagues recruited more than 500 adults with chronic rhinosinusitis. In surveys, the participants rated the severity of 22 symptoms, such as facial pain and how runny their nose was, with an average score of 55 out of 110.

The team then randomly assigned the participants to take either a three-month course of clarithromycin, placebo pills or undergo nasal surgery. All the participants also used nasal sprays and rinsed their noses with saline.

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Six months later, those who took either clarithromycin or placebo pills reported a roughly 10-point reduction in the severity of their symptoms compared with before the treatment, a level that would noticeably improve their quality of life, says team member at King’s College London. But since the effect was seen in both the antibiotic and placebo groups, it was probably due to the nasal sprays and rinsing, she says.

Those in the surgery group saw a roughly 30-point improvement in their symptoms compared with before surgery, suggesting doctors should offer this instead of antibiotics, says Hopkins.

There is an important caveat, however. About 80 per cent of the participants had nasal polyps, possibly because the study took place during the covid-19 pandemic, and catching the coronavirus may trigger the , says Hopkins. Further studies are needed to check whether the results apply to those without polyps, who we know harbour different types of inflammation, she says.

A common form of weight-loss surgery may cut the risk of colorectal cancer by altering levels of molecules called bile acids in the blood and small intestine. The findings could lead to new treatments for bowel cancer.

Gastric bypass surgery involves stapling the stomach to form a small upper pouch and a larger lower pouch. The small intestine is then connected to the upper pouch so food and digestive juices bypass most of the stomach and the start of the small intestine. After having the surgery, people typically feel full sooner and lose weight.

Prior studies have also linked the procedure to a , but it was unclear why. To find out, at the University of Freiburg in Germany and her colleagues fed mice a high-fat diet until they gained around 50 per cent of their initial body weight, on average. They then gave a third of the mice gastric bypass surgery while the rest underwent sham surgery that didn’t rearrange their digestive organs.

Aiming to isolate the effect of having gastric bypass surgery from that of losing weight, the team put the gastric bypass group and half of the remaining mice on a diet that caused them to lose about a fifth of their weight, on average, over six weeks.

The researchers then implanted colorectal cancer cells into the mice’s colons. After another six weeks, they found that colon tumours in the gastric bypass group were two-thirds smaller than those of either the mice that had kept gaining weight or the mice that had lost weight through diet alone.

What’s more, tumours had spread to the liver in only one mouse out of 20 in the gastric bypass group, while this occurred in most animals in the sham groups.

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“As both sham groups had similar tumour levels but different weights, weight loss itself didn’t account for the reduced cancer risk – there was something else about bypass surgery,” says Kesselring.

The team wondered if changes in bile acids, a mix of molecules that digest fats, might be responsible. These are usually made by the liver and pass through the gall bladder, stomach and small intestine before returning to the liver via the blood.

“With bypass surgery, bile acids are introduced later into the small intestine,” says Kesselring. This means they may encounter a different mix of gut bacteria, which chemically alter the molecules.

The mice that underwent gastric bypass surgery had reduced levels of some bile acids called primary bile acids in their colons and blood compared with those in the sham groups.

To test whether bile acid changes really did alter cancer risk, the team put another group of mice through the same experiment – but instead of gastric bypass surgery, these mice had an operation that simply diverted their bile acids to a later part of their small intestine without altering the stomach.

Crucially, the team found that this lowered levels of primary bile acids in the blood and reduced the size and spread of colorectal tumours in these mice as effectively as gastric bypass surgery. This was supported by another experiment where the team found that primary bile acids boost the growth of colorectal cancer cells in a lab dish.

The findings suggest that targeting primary bile acids could help treat cancer. “We could maybe figure out some oral drug that reduces these bile acids, that we could give to people with cancer, to simulate some of these beneficial effects of [gastric bypass] surgery,” says at Louisiana State University.

Instead of administering general anaesthesia, which is the default for such an operation, doctors gave a spinal anaesthesia, similar to that used during Caesarean sections. The transplant took less than 2 hours.

Nicholas was completely aware and awake during his surgery, but experienced “no sensation whatsoever” and was able to talk with the surgeons about the different milestones they reached during the procedure.

After a successful operation on 24 May, he was discharged the next day, walking out of Northwestern Memorial Hospital. The normal stay there for kidney transplant patients is two to three days.

This new option may increase access to transplantation for people who are at high risk of complications from general anaesthesia, while also decreasing time spent in hospital. ⁠