Medical Bulletin 03/February/2024

Here are the top medical news of the day:

Age-Related Brain Changes and Pain Sensitivity: Impact on Older Women

A new study has found that the brain system enabling us to inhibit our own pain changes with age, and that gender-based differences in those changes may lead females to be more sensitive to moderate pain than males as older adults. The study was published recently in The Journal of Pain.

Researchers used fMRI scans to examine brain responses in men and women who had rated the intensity and unpleasantness of pain during exposure to increasing levels of heat. The results suggested that established gender differences in pain perception could likely be traced at least in part to this brain network, and offered new evidence that those gender differences may become more disparate with age.

“The most novel part of this study is looking at gender by age,” said lead study author Michelle Failla, assistant professor in the College of Nursing at The Ohio State University. “Most of the work characterizing which regions in the brain respond to pain have been done in people aged 18 to 40. We want to understand what’s happening between the ages of 30 and 90 years old because that’s when people are beginning to experience chronic pain.”

In this study, the researchers specified that they holistically examined gender-based differences that may relate not just to biological sex, but also to social factors that influence how people respond to pain.    

Reference: Brain changes behind pain sensitivity may affect older women more; Journal of Pain; DOI: 10.1016/j.jpain.2023.10.027

Dynamic Energy Supply for Firing Nerve Fibers in the Brain

Brain function depends on the swift movement of electrical signals along axons, the long extensions of nerve cells that connect billions of brain cells. The nerve fibers are insulated by a fatty layer called myelin, which is produced by specialized cells called oligodendrocytes. These cells wrap around and insulate nerve fibers ensuring the rapid and efficient transmission of signals that is essential for brain function.

Oligodendrocytes sense and respond to the electrical signals. “We found that oligodendrocytes not only detect the signals from active nerve fibers, but also respond to them by immediately accelerating their consumption of glucose, a primary energy source,” says Saab. In this way, the oligodendrocytes deliver energy-rich molecules to the rapidly firing axons to support their dynamic energy needs.

To understand how electrically active axons communicate with their surrounding oligodendrocytes, the researchers studied the mouse optic nerve, an ideal pathway for stimulating and monitoring the electrical activity of myelinated axons.

Reference: Firing nerve fibers in the brain are supplied with energy on demand; Nature Neuroscience

Diabetes medication class tied to lower risk of kidney stones

Rates of kidney stones are on the rise in the United States and around the world. Type 2 diabetes is associated with increased risk of kidney stones, but some forms of treatment for this condition may also have the benefit of lowering risk of kidney stones. In a study led by investigators from Mass General Brigham, researchers found that there was an association between the use of sodium-glucose contratransporter 2 (SGLT2) inhibitors and a lower risk of developing kidney stones. Their findings are reported in JAMA Internal Medicine.

Researchers from Brigham and Women’s Hospital and Massachusetts General Hospital, founding members of the Mass General Brigham healthcare system, worked together to conduct the analysis. The study included data from three nationwide databases of patients with type 2 diabetes who were seen in routine clinical practice. 

Reference: Diabetes medication class tied to lower risk of kidney stones; JAMA Internal Medicine; DOI: 10.1001/jamainternmed.2023.7660