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June 29, 2018
Digest

Researchers Find Link Between Allergen in Red Meat, Heart Disease

Researchers have linked sensitivity to an allergen in red meat to the buildup of plaque in the arteries.
Researchers have linked sensitivity to an allergen in red meat to the buildup of plaque in the arteries.

IMAGE: RIBEIROROCHA/THINKSTOCK

A team of researchers says it has linked sensitivity to an allergen in red meat to the buildup of plaque in the arteries of the heart. While high saturated fat levels in red meat have long been known to contribute to heart disease for people in general, the new finding suggests that a subgroup of the population may be at heightened risk for a different reason–a food allergen.

The study, which is supported by NHLBI, appears in Arteriosclerosis, Thrombosis, and Vascular Biology, a peer-reviewed journal of the American Heart Association.

“This novel finding from a small group of subjects from Virginia raises the intriguing possibility that allergy to red meat may be an under-recognized factor in heart disease,” said study leader Dr. Coleen McNamara, a professor of medicine in the Cardiovascular Research Center of the University of Virginia Health System, Charlottesville. “These preliminary findings underscore the need for further clinical studies in larger populations from diverse geographic regions and additional laboratory work.”

The number of people with red meat allergies in the United States is unclear, but researchers estimate that it may be 1 percent of the population in some areas. The number of people who develop blood antibodies to the red meat allergen without having full-blown symptoms is much higher—as much as 20 percent of the population in some areas, the researchers say.

High Thyroid Hormone Level in Early Pregnancy Linked to Gestational Diabetes

Women in early pregnancy who have high levels of a certain thyroid hormone may be at greater risk for gestational diabetes, compared to women who have normal levels of the hormone, according to researchers at NICHD. Their study appears in the Journal of Clinical Endocrinology and Metabolism.

The researchers found that pregnant women with the highest levels of the thyroid hormone triiodothyronine (T3) were more than four times more likely to develop gestational diabetes, compared to women with lower levels of the hormone. T3 is produced from the related hormone thyroxine (T4). The researchers also found that a high T3/T4 ratio—which indicates a high conversion rate from T4 to T3—was strongly associated with a higher risk for gestational diabetes.

To conduct the study, researchers evaluated medical records of 107 women with gestational diabetes, comparing them to 214 pregnant women who had not developed the condition. The women had taken part in the NICHD Fetal Growth Study, a diverse sample of more than 2,300 participants.

Study authors note that abnormal thyroid functioning has been linked to miscarriage and preterm birth. Their findings suggest that screening pregnant women for thyroid disease early in pregnancy could help identify women at high risk for gestational diabetes and other pregnancy-related complications.

Eosinophilic Esophagitis Due to Missing Protein?

People with EoE experience difficulty swallowing and nutritional problems because an accumulation of immune cells scars the esophagus.
People with EoE experience difficulty swallowing and nutritional problems because an accumulation of immune cells scars the esophagus.

IMAGE: DIGITAL VISION/THINKSTOCK

Scientists have discovered that the absence of a specific protein in cells lining the esophagus may cause inflammation and tissue damage in people with eosinophilic esophagitis (EoE). EoE affects as many as 150,000 people in the United States, many of whom are children.

People with EoE experience difficult or painful swallowing, vomiting and nutritional problems because an accumulation of immune cells called eosinophils scars the esophagus.

The researchers found that the protein SPINK7 was nearly absent in esophageal biopsies taken from adults and children with active EoE but was prevalent in biopsies from healthy people. In a healthy esophagus, SPINK7 tamps down inflammation and helps preserve tissue structure.

Encouragingly, a licensed drug for emphysema reversed damaging inflammation in tissues lacking SPINK7, the investigators report in a paper posted online June 6 in Science Translational Medicine. The researchers received support from NIAID and NIDDK.

Because food contains enzymes that can damage human tissue, the lining of the esophagus normally protects itself by producing its own enzymes that degrade the offending proteins and thus protect the lining.

Researchers led by Dr. Marc Rothenberg at Cincinnati Children’s found that SPINK7 facilitates this protective process. When they silenced SPINK7, the gene that codes for SPINK7, in cells derived from esophageal tissues, the research team discovered that large gaps formed between the cells lining the esophagus. These cells also lost barrier functions that ordinarily move food along the digestive tract.

Tissues that did not express SPINK7 also produced high levels of chemical messengers called cytokines that attract eosinophils and produce the same type of inflammation seen in allergic diseases.

No Link Found Between Brain Injury and IV Fluid Treatment of Pediatric Diabetic Ketoacidosis

Giving children intravenous (IV) fluids to treat diabetic ketoacidosis—an emergency complication of untreated diabetes—does not appear to worsen the brain swelling that may accompany the condition, according to a study supported by NICHD. The findings, published in the New England Journal of Medicine, contrast with widespread concern that providing too much IV fluid may result in serious brain injury.

Diabetic ketoacidosis is often the first sign of type 1 diabetes in children who have not yet been diagnosed. Deprived of glucose, the liver converts body fat into ketones, which turn the blood acidic. Untreated diabetic ketoacidosis can be fatal.

The study was conducted at 13 U.S. emergency departments that participate in the Pediatric Emergency Care Applied Research Network. It enrolled more than 1,300 children with diabetic ketoacidosis.

The research team, led by investigators at the University of California, Davis, divided the children into four treatment regimens, varying the amount and rate of IV fluid infusion—from rapid or gradual—and varying the sodium content of the fluid.

Researchers found no difference in brain injury rates among the treatment regimens. Neither the infusion rate nor the sodium content of the fluid significantly influenced neurological outcomes of the children in the study.

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