Healing in utero

Every year, nearly 24,000 women in the United States miscarry a child. Research at the University of California, San Francisco, offers hope to parents whose babies have metabolic disorders that often cause a miscarriage.

In a study published Feb. 26 in the journal Science Translational Medicine, scientists attempted to heal fetal mice carrying the genetic mutation that causes MPS7, or Sly syndrome. The mutation causes the body’s cells to lack a crucial enzyme and can lead to fetal death, fluid on the brain, organ damage, and other muscle and bone deformities. In adults, MPS7 can cause joint stiffness, short stature, hearing loss, cataracts, and clouding of the corneas. It can also cause developmental delays.

Scientists transplanted normal adult stem cells into fetal rats with the disease. In the brain, they developed into microglia, nerve cells that could not only make and store the missing enzyme but also could remove damaged neurons and fight infections. The stem cells found their way to the liver, kidneys, and other internal structures, where they grew into cells that produced the needed enzyme for those organs. They even delivered the enzyme to nearby cells and restored their function.

Former studies experimented with transplanting healthy stem cells into fetal rats after birth, but scientists could not get the cells to cross the blood-brain barrier. That wasn’t a problem when they did the transplants in utero.

“One of our big findings is that these cells truly do become microglia, so there’s a huge advantage to transplanting them before birth,” researcher Quoc-Hung Nguyen said in a statement.

If this research moves into human clinical trials, unborn infants could receive stem cell transplants from either healthy bone marrow donors or their mothers, said lead author Tippi MacKenzie. Because mothers carry these genetic diseases, the scientists would need to correct the mutation in the cells before transplant.

MacKenzie and Nyugen said their approach may prove an effective treatment for many hereditary metabolic disorders linked to faulty mutations in single genes. Doctors could perform in utero stem cell transplants the same way many centers already carry out fetal blood transfusions, making the treatment accessible for many families if it’s approved.

“These exciting findings are just the tip of the iceberg,” Nyugen said. “They open up a whole new approach to treating a range of diseases. At the same time, there’s also a lot of work to do to optimize the treatment for humans.”

MacKenzie is currently testing transplanting mothers’ stem cells into developing fetuses to treat a blood disorder called alpha thalassemia.

Soda tax fail

The City of Brotherly Love’s attempt to break people’s soda habits doesn’t seem to be working.

In December 2016, Philadelphia became the first major U.S. city to levy a tax of 1.5 cents per ounce on sugary beverages, whether sweetened with natural sugar, high fructose corn syrup, or artificial sweeteners. The law made some exceptions for milk, fruit juice, and vegetable products. Under the tax, a 20-ounce bottle of soda costs an extra 30 cents, and the price of a 2-liter bottle goes up a dollar.

When lawmakers first implemented the tax, researchers from Drexel University surveyed 515 adult Philadelphians, along with residents of neighboring cities, about their beverage habits. One year later, they surveyed the same group again. They found no significant difference in the amount of sugary drinks the group consumed, according to a study published Feb. 19 in the International Journal of Environmental Research and Public Health.

Other studies found a drop when they measured the sales, rather than consumption, of sugary beverages in cities with soda taxes. That could mean people just started buying their sodas in places that did not have the tax.

Critics of soda tax laws say they represent government overreach and disproportionately affect the poor. In 2013, then–New York City Mayor Michael Bloomberg proposed a ban on sweetened drinks larger than 16 ounces. Officials scheduled the ban to go into effect on March 12, 2013, but lower court decisions blocked it. On June 26, 2014, the New York Court of Appeals, the state’s highest court, ruled that the New York City Board of Health’s proposed cap overstepped its authority.

Albany, N.Y.; Boulder, Colo.; and Seattle levy some type of soda tax, along with the California cities of Berkeley, Oakland, and San Francisco. —J.B.

Electricity out of thin air

Electrical engineers and microbiologists at the University of Massachusetts Amherst figured out how to use bacteria to generate electricity from the air. The researchers used a bacteria called Geobacter that sprouts microbial nanowires, protein appendages that can conduct electricity. They published their findings in Nature on Feb. 17.

The researchers sandwiched a thin film of the nanowires, only 10 microns thick, between two electrodes. (A human red blood cell is about 5 microns wide.) Together, the protein’s electrical conductivity, the chemical properties on the surface of the nanowires, and fine pores between the nanowires within the film generated an electrical current between the two electrodes when exposed to water vapor in the air.

The researchers call the device an air-gen, short for air-powered generator. It produces energy even in very low-humidity environments like the Sahara Desert without sunlight or wind. It can even work indoors.

The researchers plan to design a small air-gen patch to power fitness monitors and smartwatches. They also hope air-gens could eventually replace cellphone chargers. Ultimately, they envision larger-scale systems, like incorporating air-gens into wall paint to power a home or building stand-alone generators that could supply electricity off the grid. —J.B.

Controlling the weather

Scientists have speculated for decades about artificially producing precipitation. People have “seeded” clouds hoping to produce rain or snow since the 1940s, but they couldn’t measure whether it worked. Researchers from the University of Colorado used a new combination of radar snow gauges and improved weather instruments to measure the effects of cloud seeding on snowfall for the first time. They published the study in the Proceedings of the National Academy of Sciences on Feb. 24.

In January 2017, atmospheric scientists used a series of flares to inject particles of silver iodide into a natural cloud formation. The particles froze around lighter drops of water vapor in the clouds and formed snow. The plane zigzagged as it flew to create a distinctive pattern in the sky that would enable the researchers to tell whether seeding or nature produced the resulting snowfall.

During the first seeding, snow fell for about 67 minutes and dusted close to 900 square miles of land with about one-tenth of a millimeter of snow. That doesn’t sound like much, but three successive seedings produced enough snow to fill about 282 Olympic-sized swimming pools, the researchers said.

In 2019, Colorado formed a partnership with six other states along the Colorado River to use cloud seeding to increase the river’s water supply. More than 50 countries, including the United States, currently use cloud-seeding programs. —J.B.