This is a recurring column on early-stage research in animals or other laboratory models that has not entered the clinic yet but could have implications for future research and development of human medicines.

Treating toxoplasmosis in mice

Scientists at the Indiana University School of Medicine have reversed behavioral changes in mice associated with Toxoplasma gondii by treating the parasite with an old drug used for high blood pressure, according to a study published April 30 in the journal mBio.

Toxoplasmosis gondii is a single-celled brain parasite that causes the disease toxoplasmosis, which is the leading cause of death attributed to foodborne illness in the U.S., according to the Centers for Disease Control and Prevention. About 40 million people in the U.S. are carriers of the parasite, but symptoms are rarely present because the immune system keeps the parasite from causing illness, according to the agency.

The parasite, which forms cysts in the brain when storing itself, is permanent and cannot be treated with existing drugs. Latent toxoplasmosis is correlated with neurological dysfunction in humans, according to the study.

Toxoplasmosis causes "dramatic behavioral changes" in mice, making them less averse to taking risks, according to the study. The behavioral changes in infected mice make them more likely to be eaten by cats, the only host that supports the sexual stage of the parasite.

The study built on previous research from the team, which showed that the number of cysts could be reduced by treating mice with guanabenz, an antihypertensive drug. After the first study concluded, lead scientists Bill Sullivan and Ronald Welk focused on reversing hyperactivity in infected mice.

Their most recent study found that hyperactivity induced by the parasite could be reversed in two strains, BALB/c and C57. The treatment reduced cyst numbers in BALB/c mice but was ineffective for reducing cyst counts in C57 mice.

The authors of the study believe that the reverse of hyperactivity correlates to a decrease of neuroinflammation as opposed to the reduction of cyst numbers, which suggests that "some behavioral changes rise from host responses to infection."

'They're coming to get you, Barbara.'

Possibly feeding off of pop culture's affinity for the undead, scientists recently restored partial brain activity to a pig four hours after it died.

A research team with Yale University circulated specially designed chemical solutions through the postmortem brain of a pig from a meatpacking plant and observed that basic circular and cellular functions returned to the organ, according to a study published April 17 in Nature. The restored functions were previously thought to disappear minutes and even seconds after oxygen and blood flow to the brain ceased, according to a press release from Yale University.

Researchers were inspired to pursue the study after observing cellular viability in small tissue cells hours after death. The scientists' technique — which they call BrainEx — could be used to investigate causes of brain disorders and may help find a way to restore brain functions to stroke patients, according to the press release. However, there is no immediate clinical application for the technique.

While basic cellular activity did return to the dead pig's brain, Zvonimir Vrselja, a co-author of the study, said there was no "organized electrical activity associated with perception, awareness, or consciousness."

"Clinically defined, this is not a living brain, but it is a cellularly active brain," Vrselja said.

Researchers were prepared in case electrical activity did return, however. Stephen Latham, co-author and director of Yale's Interdisciplinary Center for Bioethics, noted that "researchers were prepared to intervene with the use of anesthetics" if any electrical activity reemerged.

Latham stressed that reestablishing consciousness was not the purpose of the study, and said that any attempts to reestablish consciousness to dead pigs or other animals would require "clear ethical standards and institutional oversight mechanisms."

Creating transparent human organs

Scientists with the Ludwig Maximilians University in Munich, Germany, have developed techniques to recreate the entire internal structure of an organ by making it transparent, according to an April 24 article from Reuters.

The research team developed a solvent to make organs like brains and kidneys transparent and scanned the organs with lasers in a microscope. This process recreated the entire internal structure of the organ, allowing scientists to see a detailed picture of the organ that was previously unavailable.

Ali Eturk, the lead researcher, believes that the process could lead to three-dimensional printing of human organs for transplants.

"We can see where every single cell is located in transparent human organs. And then we can actually replicate exactly the same, using 3D bioprinting technology to make a real functional organ," Eturk told Reuters.

The team plans to create a bioprinted pancreas and kidney over the next six years.