For Cynthia Schraf-Fletcher, 74, the results were “remarkably” successful.

Nearly a year after receiving genicular artery embolization (GAE) on her right knee, Schraf-Fletcher says the improvement is comparable to the total knee replacement she previously underwent on her left knee.

“I couldn’t be more pleased,” says Schraf-Fletcher, who had the procedure performed by Leigh Casadaban, MD, MS, assistant professor of radiology at the University of Colorado Anschutz School of Medicine.

Today, she says everyday activities such as gardening and riding a stationary bicycle are far more enjoyable because of the reduction in pain.

How Genicular Artery Embolization Works

GAE is an outpatient procedure designed to ease chronic knee pain by reducing blood flow to inflamed areas within the joint. By targeting abnormal blood vessels associated with inflammation, the treatment can help decrease swelling and discomfort.

“For treating osteoarthritis in the knees, we often think of medications, physical therapy, maybe a steroid injection, and then on the far end of the spectrum is a total knee replacement. There really hasn’t been anything for patients in between,” Casadaban, a vascular interventional radiologist, says. “GAE is a promising minimally invasive procedure that may fill that spot for people who have failed conservative treatments but are not yet ready to have a major surgery.”

According to Casadaban, people with mild to moderate osteoarthritis tend to benefit the most. Patients with more advanced disease can also undergo the procedure, although the effects are generally less durable.

“We find about 70% of patients have phenomenal results. They cut their pain scores in half, sometimes more. We have a few patients with no pain at all after the procedure,” Casadaban says. “Patients that have tried a lot of other treatments and haven’t had pain relief are happy to get back to their normal activities.”

After experiencing complications from knee replacement surgery, Schraf-Fletcher was eager to explore another option. Looking back, she says choosing GAE was the right decision.

What Happens During the Procedure?

GAE typically takes between one and two hours and is performed under conscious sedation.

During the procedure, an interventional radiology team makes a small incision near the crease of the leg. Using X-ray imaging and contrast dye for guidance, doctors advance a tiny catheter through the femoral artery until it reaches the genicular arteries around the knee.

Once in position, the team releases microscopic beads that block blood flow to the abnormal vessels located in the painful areas identified by the patient.

Patients are monitored for several hours afterward and are usually able to return home the same day. Doctors generally advise taking it easy for a few days during recovery.

Originally developed in Japan a little more than a decade ago, GAE has steadily gained attention worldwide. Since 2021, the FDA has granted “breakthrough device status” to multiple devices related to the procedure in the United States.

Research Suggests Long Lasting Pain Relief

Early and ongoing research continues to produce encouraging results.

“The theory is that GAE reduces inflammation inside the knee joint, and symptom relief can last years,” Casadaban says. “Four-year data published in Japan shows that if you have one outpatient procedure, your pain relief can last for those four years. In the U.S., we now have two-year data, which shows that if you have a good response, pain relief can last two years. That really speaks to the theory that we’re hopefully modifying something in the joint.”

Casadaban is currently leading two clinical trials at CU Anschutz. One study is examining changes in knee fluid among patients receiving GAE. The other is evaluating a temporary arterial treatment device called Nexsphere-F, which blocks small blood vessels in the knee that may contribute to inflammation and pain.

Expanding Beyond Knee Osteoarthritis

Osteoarthritis is a degenerative joint disease that affects millions of people each year and can occur in many different joints throughout the body.

Although GAE is currently used only for knee conditions, Casadaban says researchers and physicians are beginning to explore its use for other painful musculoskeletal disorders, including frozen shoulder, tennis elbow, and plantar fasciitis.

The findings come from an analysis of 17 tyrannosaur fossils spanning a wide range of ages, from young juveniles to massive adults. Researchers say the work provides the most detailed reconstruction yet of how Tyrannosaurus grew throughout its life.

The study was published in the journal PeerJ.

Reading the Growth Rings Hidden Inside Dinosaur Bones

To estimate the age of dinosaurs, paleontologists often examine growth rings preserved inside fossilized bones. These rings are somewhat similar to the annual rings found in tree trunks. Each growth mark can provide clues about how quickly an animal was growing and how old it was when it died.

For decades, scientists have used these rings to reconstruct the life history of Tyrannosaurus rex. However, the new study employed more advanced techniques than earlier investigations. Researchers examined thin slices of fossil bone under specialized lighting that can reveal growth rings that are difficult to detect using standard methods.

The team also used sophisticated statistical models to combine information from multiple specimens. This allowed them to create a more complete picture of growth across the entire lifespan of T. rex.

The results indicate that Tyrannosaurus remained in a growth phase about 15 years longer than previously thought.

In addition, the findings suggest that some fossils traditionally assigned to T. rex may actually belong to other closely related species, or differ for other biological reasons.

Largest T. Rex Dataset Ever Assembled

“This is the largest data set ever assembled for Tyrannosaurus rex,” says Holly Woodward, a professor of anatomy at Oklahoma State University who led the research effort. “Examining the growth rings preserved in the fossilized bones allowed us to reconstruct the animals’ year-by-year growth histories.”

Unlike a tree stump, which preserves rings from an organism’s entire life, dinosaur bones provide only a partial record. A cross section of a T. rex leg bone typically preserves information from just the final 10 to 20 years of the animal’s life.

To overcome that limitation, the researchers combined growth records from multiple individuals of different ages.

“We came up with a new statistical approach that stitches together growth records from different specimens to estimate the growth trajectory of T. rex across all stages of life in greater detail than any previous study,” explains Nathan Myhrvold, a mathematician and paleobiologist at Intellectual Ventures who led the statistical analysis.

“The composite growth curve provides a much more realistic view of how Tyrannosaurus grew and how much they varied in size.”

A Slower Path to Becoming a Giant Predator

The new results paint a different picture of Tyrannosaurus development than earlier studies.

Instead of rapidly reaching adulthood, T. rex appears to have grown at a steadier pace over several decades. According to the researchers, this prolonged growth period may have helped younger tyrannosaurs occupy different ecological niches as they matured.

In ecology, a niche refers to the role an organism plays within its environment, including what it eats, where it lives, and how it interacts with other species.

“A four-decade growth phase may have allowed younger tyrannosaurs to fill a variety of ecological roles within their environments,” says coauthor Jack Horner of Chapman University. “That could be one factor that allowed them to dominate the end of the Cretaceous Period as apex carnivores.”

The Cretaceous Period ended about 66 million years ago, shortly before the extinction of non-avian dinosaurs.

Are Some Famous T. Rex Fossils Actually Different Species?

The study also contributes to an ongoing debate among paleontologists.

Although Tyrannosaurus rex is one of the most famous dinosaurs ever discovered, some researchers have argued that not every fossil labeled as T. rex necessarily belongs to the same species.

One controversial proposal suggests that several smaller fossils represent a separate dinosaur called Nanotyrannus rather than young Tyrannosaurus individuals. Other researchers have proposed that even some large specimens may belong to multiple closely related species.

The issue remains unresolved.

To investigate the question, the researchers included 17 fossils belonging to what they describe as the “Tyrannosaurus rex species complex,” a term acknowledging the possibility that more than one species or subspecies could be represented.

Two particularly famous specimens, nicknamed “Jane” and “Petey,” stood out from the rest. Their growth patterns differed significantly from those of the other fossils in the study.

While growth data alone cannot determine whether these animals belonged to different species, the unusual patterns make that possibility worthy of further investigation.

The researchers note that a separate recent study by Zanno and Napoli reached a similar conclusion using different methods, classifying Jane and Petey as two distinct species of Nanotyrannus.

Hidden Growth Rings Could Change Dinosaur Research

Another important finding involves the discovery of previously overlooked growth markers inside dinosaur bones.

Woodward, Myhrvold, and Horner found that circularly polarized and cross-polarized light can reveal a new type of growth ring. These hidden features may help explain discrepancies that have puzzled researchers studying dinosaur growth.

Because the approach is supported by strong statistical evidence, it could influence how scientists examine fossils in future studies, not only for T. rex but for many other dinosaur species as well.

“Interpreting multiple closely spaced growth marks is tricky,” Myhrvold says. “We found strong evidence that the protocols typically used in growth studies may need to be revised.”

A New Look at the Life of Tyrannosaurus Rex

More than a century after Tyrannosaurus rex was first described by scientists, the giant predator continues to reveal new surprises.

By combining a larger fossil sample, improved imaging techniques, and innovative statistical analysis, the new research provides one of the clearest views yet of how T. rex developed from a young dinosaur into one of the largest and most formidable land predators in Earth’s history.

The findings suggest that the king of dinosaurs may have taken far longer to grow up than anyone previously realized.

The work was led by teams from the CIBER Area for Diabetes and Associated Metabolic Diseases (CIBERDEM) at the University of Barcelona.

“Palmitic acid, a saturated fatty acid widely found in foods, is associated with impaired insulin sensitivity, whereas oleic acid, abundant in olive oil, may have a protective effect against these metabolic disorders,” says Professor Manuel Vázquez-Carrera, from the UB’s Faculty of Pharmacy and Food Sciences, the UB Institute of Biomedicine (IBUB), the Sant Joan de Déu Research Institute (IRSJD) and CIBERDEM.

Other contributors include Ricardo Rodríguez-Calvo of CIBERDEM at the Pere Virgili Institute for Health Research (IISPV), Marta Tajes of the CIBER Area for Cardiovascular Diseases (CIBERCV) at the Bellvitge Biomedical Research Institute (IDIBELL), and Walter Wahli of the University of Lausanne (Switzerland).

According to Vázquez-Carrera, the findings suggest that the type of fat people consume may be more important than the overall amount.

“This review highlights the significant role of the quality of dietary fat, rather than the total amount consumed,” notes Professor Manuel Vázquez-Carrera, who is a group leader at CIBERDEM at the UB.

How Palmitic Acid May Promote Diabetes

The researchers examined evidence showing that palmitic acid can trigger several biological processes linked to metabolic disease.

As Xavier Palomer (UB-IBUB-CIBER-IRSJD), the article’s first author, says, “at the molecular level, palmitic acid promotes the accumulation of potentially toxic bioactive lipids, fosters low-grade chronic inflammation, and contributes to the dysfunction of cellular organelles, such as the endoplasmic reticulum and the mitochondria.”

The team notes that these cellular changes “are closely linked to impaired insulin action and the progression of metabolic disease.”

Oleic Acid Shows Protective Effects

The picture looks quite different for oleic acid, a monounsaturated fat found in high amounts in olive oil.

According to the review, oleic acid encourages the body to store fats in forms that are metabolically less disruptive and have little effect on normal cellular function. It also helps maintain healthy insulin signaling in important metabolic tissues, including the liver, muscles, and adipose tissue.

Researchers say oleic acid may also offset many of the harmful effects associated with palmitic acid. This could help explain why eating patterns rich in monounsaturated fats, including the Mediterranean diet, are consistently linked to a lower risk of type 2 diabetes and other metabolic disorders.

Improving Nutrition Strategies for Diabetes Prevention

The authors emphasize that more targeted research is needed to better understand differences seen across population studies.

“It is important to consider variables such as the source of fatty acids, their dietary context, interactions with other nutrients, and different food processing methods,” says Manuel Vázquez-Carrera.

The researchers believe that gaining a clearer understanding of these factors will improve scientists’ ability to evaluate how different fats affect metabolic health. In turn, that knowledge could support the development of more effective dietary approaches for preventing and managing type 2 diabetes.