Daily ReCAP April 5, 2017

Chronic: Monitoring Blood Glucose Levels with Biosensing Contact Lenses

Contact lenses embedded with transparent biosensors could soon help physicians and patients with diabetes track their health without invasive tests. The investigators first developed an inexpensive method to make IGZO electronics, and they used the approach to fabricate a biosensor that contained a transparent sheet of IGZO field-effect transistors and glucose oxidase. When glucose was added to the mixture, the enzyme oxidized the blood sugar causing the pH level in the mixture to shift, triggering changes in the electrical current flowing through the IGZO transistor. Additionally, the investigators created nanostructures within the IGZO biosensor that can detect glucose concentrations much lower than found in tears. In theory, more than 2500 biosensors each measuring a different bodily function could be embedded in an IGZO contact lens, according to the investigators. Once fully developed, the biosensors could transmit vital health information to smartphones and other Wi-Fi, Bluetooth-enabled devices. Although the IZO system has already been used in catheters to measure uric acid, it could be more than a year before a prototype biosensing contact lens would be ready for animal testing. The findings were presented at the 253rd National Meeting & Exposition of the American Chemical Society.

Acute: Monounsaturated Fats Stored in Guts of Roundworms Helps Extend Their Lifespan

Monounsaturated fats that accumulate in the guts of roundworms help increase their lifespan, according to a study published inNature. “We have known for some time that metabolic changes can affect lifespan, but we expected the long-lived animals in our study would be thinner,” said senior author Anne Brunet, PhD. “Instead, they turned out to be fatter. This was quite a surprise.” For the study, investigators sought to examine the effect of blocking the activity of the complex proteins COMPASS, on the metabolism of laboratory roundworms. Together, the COMPASS proteins add chemical tags called methyl groups to a histone. The presence or absence of the tags affects whether the DNA remains wound up tightly or unfurls to allow its genes to be expressed. In prior studies, the investigators had shown that worms lacking COMPASS activity lived approximately 30% longer than their counterparts. “We thought that this epigenetic modification caused by COMPASS might mimic dietary restriction,” Brunet said. “So, we began looking at the metabolism and fat content of worms lacking COMPASS activity.” Worms that lacked a functional COMPASS complex lived longer and had an accumulation of fats in their guts. Upon further examination using gas chromatography and mass spectrometry, the investigators found that the fat was primarily monounsaturated fatty acids, a fat found in olive oil, avocados, and nuts. When COMPASS activity was inhibited in the germline, it caused a specific increase in the expression of enzymes that convert polyunsaturated fats into monounsaturated fats in the animals’ guts. To determine if the accumulation of monounsaturated fats was important to lifespan, the investigators fed monounsaturated and polyunsaturated fats directly to the worms. The findings showed that the monounsaturated fats accumulated in the worms’ guts and increased their lifespan even when COMPASS was not mutated. Contrastingly, polyunsaturated fats did not have the same effect. Currently, investigators are working to uncover how the monounsaturated fatty acid accumulation may work to extend life span.

Preventive: Upping Potassium Intake May Help Lower Blood Pressure

Scientists have found a link between the increase in dietary potassium and lower blood pressure. The World Health Organization estimates that hypertension accounts for at least 51% of deaths due to stroke and 45% of deaths due to heart disease. In a study published in theAmerican Journal of Physiology—–Endocrinology and Metabolism, investigators sought to explore the link between blood pressure and dietary sodium, potassium, and the sodium-potassium ratio. They examined population, interventional, and molecular mechanism studies that investigated the effects of dietary sodium and potassium on hypertension. The results of the study showed that several population studies demonstrated that higher dietary potassium was associated with lower blood pressure, regardless of sodium intake. Interventional studies with potassium supplementation also suggested that potassium provides a direct benefit. To illustrate the mechanisms for potassium benefit, the investigators reviewed recent studies in rodent models from their lab and others. The studies indicated that the body performs a balancing act that uses sodium to maintain close control of potassium levels in the blood. “When dietary potassium is high, kidneys excrete more salt and water, which increases potassium excretion,” said author Alicia McDonough, PhD. “Eating a high potassium diet is like taking a diuretic. If you eat a typical Western diet, your sodium intake is high and your potassium intake is low This significantly increases your chances of developing high blood pressure.” McDonough recommends developing public policies to increase the intake of dietary potassium from plant-based sources, as well as to add potassium content to nutrition labels to help raise awareness.