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November 18, 2016
Digest

New Method for Aortic Valve Replacement Proves Successful in High-Risk Patients

Researchers at NIH have developed a new, less invasive way to perform transcatheter aortic valve replacement (TAVR), a procedure widely used to treat aortic valve stenosis, a lethal heart condition. The new approach, called transcaval access, will make TAVR more available to high-risk patients, especially women, whose femoral arteries are too small or diseased to withstand the standard procedure. The Journal of the American College of Cardiology published the findings.

Aortic valve stenosis involves the narrowing of the heart’s aortic valve, which reduces blood flow through the heart. For about 85 percent of patients with this condition, doctors typically perform TAVR through the femoral artery in the leg. But for the other 15 percent, doctors must find a different access route. The most common alternative routes are through the chest, which requires surgery and are associated with significantly more complications.

Transcaval access, which can be performed in awake patients, involves electrifying a small wire so that it crosses between neighboring blood vessels in the abdomen. The technique calls for making large holes in both the abdominal aorta and the inferior vena cava, which physicians previously considered dangerous because of the risk of fatal bleeding.

The new method was developed by researchers at NHLBI and tested in a trial on 100 patients at 20 hospitals across the United States. Researchers said it proved successful in 99 of the patients.

Gene Therapy Shows Promise for Niemann-Pick Disease Type C1

For the first time, NIH researchers have demonstrated in mice that gene therapy may be the best method for correcting the single faulty gene that causes Niemann-Pick disease, type C1 (NPC1). The gene therapy involved inserting a functional copy of the NPC1 gene into mice with the disease; the treated animals were then found to have less severe NPC1 symptoms. The study, led by researchers at NHGRI and NICHD, was published Oct. 26 in the journal Human Molecular Genetics.

Niemann-Pick disease is a rare and fatal disorder of the central nervous system (the brain and spinal cord) that has no cure. The disease occurs when a faulty housekeeping gene fails to remove cell waste, like lipids and cholesterol. The accumulation of waste in the spleen, liver and brain causes progressive deterioration in intellectual and motor functions. It also shortens patients’ lives, as people with Niemann-Pick disease typically die in their teens.

The researchers’ goal was to correct the faulty NPC1 gene in as many cells and organs as possible, with a strong focus on the brain. To do this, they used a non-disease-causing virus called the adeno-associated virus serotype 9 to transfer functioning NPC1 to the cells. The AAV9 containing a functioning NPC1 gene successfully crossed the blood-brain barrier, reaching cells in the brain and elsewhere. Once inside cells, the normal NPC1 gene was then able to make the functional NPC1 protein to correct the cell defects.

With a single injection, mice showed improvements in motor coordination, weight gain and longevity compared to those without this gene therapy.

“Our work in NPC1 mice may help lead to human clinical trials and eventually FDA approval for gene therapy as a treatment for NPC1 disease,” said Dr. Charles Venditti, senior investigator in NHGRI’s Medical Genomics and Metabolic Genetics Branch. “For NPC1 patients, gene therapy could halt progression of the disease, improve the quality of their lives and, hopefully, increase the patient’s life span.”

Skin Patch to Treat Peanut Allergy Shows Benefit in Children

Study provided clues of how strongly appetite counters weight loss.

A wearable patch that delivers small amounts of peanut protein through the skin shows promise for treating children and young adults with peanut allergy, with greater benefits for younger children, according to 1-year results from an ongoing clinical trial. The treatment, called epicutaneous immunotherapy or EPIT, was safe and well-tolerated, and nearly all participants used the skin patch daily as directed.

The ongoing trial is sponsored by NIAID. One-year outcomes were published online on Oct. 26 in the Journal of Allergy and Clinical Immunology.

“To avoid potentially life-threatening allergic reactions, people with peanut allergy must be vigilant about the foods they eat and the environments they enter, which can be very stressful,” said NIAID director Dr. Anthony Fauci. “One goal of experimental approaches such as epicutaneous immunotherapy is to reduce this burden by training the immune system to tolerate enough peanut to protect against accidental ingestion or exposure.”

“The clinical benefit seen in younger children highlights the promise of this innovative approach to treating peanut allergy,” said Dr. Daniel Rotrosen of NIAID. “Epicutaneous immunotherapy aims to engage the immune system in the skin to train the body to tolerate small amounts of allergen, whereas other recent advances have relied on an oral route that appears difficult for approximately 10 to 15 percent of children and adults to tolerate.”

Nearly all of the study participants followed the EPIT regimen as directed. None reported serious reactions to the patch, although most experienced mild skin reactions, such as itching or rash, at the site of patch application.

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