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March 11, 2015
Digest

Photon-Counting CT Scanner Used in Patients for the First Time

The Clinical Center is investigating the potential use of a new generation of a computerized tomography (CT) scanner, called a photoncounting detector CT scanner, in a clinical setting. The prototype technology is expected to replicate the image quality of conventional CT scanning, but may also provide health care specialists with an enhanced look inside the body through multienergy imaging. Patients could receive a minimum amount of radiation, while the maximal amount of information needed would be delivered to health care providers.

Study participant receives a scan in the CC’s new photoncounting CT scanner.
Study participant receives a scan in the CCs new photoncounting CT scanner.

PHOTO: CLINICAL CENTER

Over the next 5 years, Dr. David Bluemke, chief of the CC department of radiology and imaging sciences, and his team will continue to develop scan protocols and image-processing algorithms, which could improve screening, imaging and treatment planning for health conditions such as cancer and cardiovascular disease.

“The NIH Clinical Center has helped shape and share research advances and health care for decades,” said Bluemke. “Now is an exciting time for us and for our study participants here in the Clinical Center as we help test and develop this CT technology so that it may one day help patients around the world and impact the health care they receive.”

Diabetes Drug May Prevent Recurring Strokes

Pioglitazone, a drug used for type 2 diabetes, may prevent recurrent stroke and heart attacks in people with insulin resistance but without diabetes. The results of the Insulin Resistance Intervention after Stroke (IRIS) trial, published in the New England Journal of Medicine, suggest a potential new method to prevent stroke and heart attack in high-risk patients who have already had one stroke or transient ischemic attack. This large, international study was supported by NINDS.

The IRIS trial is the first study to provide evidence that a drug targeting cell metabolism may prevent secondary strokes and heart attacks even before diabetes develops. Insulin regulates metabolism and keeps blood sugar levels from getting too high, along with many other processes, in the body. Insulin resistance is a condition in which the body produces insulin but does not use it effectively.

“This study represents a novel approach to prevent recurrent vascular events by reversing a specific metabolic abnormality thought to increase the risk for future heart attack or stroke,” said NINDS director Dr. Walter Koroshetz.

“The IRIS trial supports the value of more research to test the vascular benefits of other interventions such as exercise, diet and medications that have similar effects on metabolism as pioglitazone,” said lead author of the study Dr. Walter Kernan of Yale University School of Medicine.

Researchers Find Link Between Death of Tumor-Support Cells, Cancer Metastasis

Researchers have discovered that eliminating cells thought to aid tumor growth did not slow or halt the growth of cancer tumors. In fact, when the cancer-associated fibroblasts (CAFs) were eliminated after 10 days, the risk of metastasis of the primary tumor to the lungs and bones of mice increased dramatically. Scientists used bioengineered CAFs equipped with genes that caused those cells to self-destruct at defined moments in tumor progression. The study, published in Scientific Reports Feb. 19, was conducted by Massachusetts General Hospital researchers funded by NIBIB.

What causes cancer to grow and metastasize is not well understood by scientists. CAFs are thought to be fibroblast cells native to the body that cancer cells hijack and use to sustain their growth. However, because fibroblasts are found throughout the human body, it can be difficult to follow and study cancer effects on these cells.

“This work underscores two important things in solving the puzzle that is cancer,” said Dr. Rosemarie Hunziker, program director for tissue engineering at NIBIB. “First, we are dealing with a complex disease with so many dimensions that we are really only just beginning to describe it. Second, this approach shows the power of cell engineering—manipulating a key cell in the cancer environment has led to a significant new understanding of how cancer grows and how it might be controlled in the future.”

Vaginal Ring Provides Partial Protection from HIV

A ring that continuously and safely releases an experimental antiretroviral drug in the vagina provided a modest level of protection against HIV infection in women, a large clinical trial in four sub-Saharan African countries has found. The ring reduced the risk of HIV infection by 27 percent in the study population overall and by 61 percent among women ages 25 years and older, who used the ring most consistently.

These results were announced Feb. 22 and simultaneously published online in the New England Journal of Medicine.

“Women need a discreet, long-acting form of HIV prevention that they control and want to use,” said Dr. Anthony Fauci, director of NIAID, which is the primary funder of the trial. “This study found that a vaginal ring containing a sustained-release antiretroviral drug confers partial protection against HIV among women in sub-Saharan Africa. Further research is needed to understand the age-related disparities in the observed level of protection.”

Eylea Outperforms Avastin for Diabetic Macular Edema with Moderate or Worse Vision Loss

A 2-year clinical trial that compared three drugs for diabetic macular edema (DME) found that gains in vision were greater for participants receiving the drug Eylea (aflibercept) than for those receiving Avastin (bevacizumab), but only among participants starting treatment with 20/50 or worse vision. Gains after 2 years were about the same for Eylea and Lucentis (ranibizumab), contrary to year-1 results from the study, which showed Eylea with a clear advantage. The three drugs yielded similar gains in vision for patients with 20/32 or 20/40 vision at the start of treatment. The clinical trial was conducted by the Diabetic Retinopathy Clinical Research Network, which is funded by NEI.

“This rigorous trial confirms that Eylea, Avastin and Lucentis are all effective treatments for diabetic macular edema,” said NEI director Dr. Paul Sieving. “Eye care providers and patients can have confidence in all three drugs.”

Eylea, Avastin and Lucentis are all widely used to treat DME, a consequence of diabetes that can cause blurring of central vision due to the leakage of fluid from abnormal blood vessels in the retina. The macula is the area of the retina used when looking straight ahead. The drugs are injected into the eye and work by inhibiting vascular endothelial growth factor, a substance that can promote abnormal blood vessel growth and leakage.

Although the drugs have a similar mode of action, they differ significantly in cost. Study results were published online Feb. 29 in Ophthalmology.

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