Leptin And Cardiovascular Function

When Rockefeller University scientists first introduced leptin to the world in 1994, the thinking was that the newly discovered hormone represented a breakthrough in treating obesity. However, subsequent research showed that excess leptin and leptin injections can lead to resistance that all but cancels out the hormone's appetite-fighting capabilities. Moreover, scientists first thought that the leptin action took place primarily in fat cells and the brain, but over time leptin has shown up in the unlikeliest of places, including the gut, kidneys, liver, spleen, pancreas, testes, blood vessels and the heart. In addition, besides affecting your eating habits and weight, leptin can play both a protective and negative role in your cardiovascular functioning. Scientists believe that one day, measuring your leptin levels might be a new way to diagnose heart-related illnesses.

About Leptin

When studying mice in 1994, Rockefeller University scientists first noticed that mice deficient in the "ob gene," which produces leptin, ate excessively. When treated with leptin shots, they slimmed down and ate normally. That discovery has led to a common narrative that leptin is a hormone that is expressed by your fat cells, and that it binds with receptors in your brain. One leptin function is to diminish your appetite; as an energy balance regulator, leptin can dial up your calorie burning to keep your weight in a certain range. It does this by tapping into your sympathic nervous system and fat-burning mechanisms. Leptin didn't work as well in humans. Obese people, who have more body fat, also have the most leptin, but their bodies are resistant to leptin's effects.

Leptin in Cardiovascular Health

Iranian researchers reported in the "World Journal of Sport Sciences" in 2009 that leptin participates in more functions than previously known. For example, leptin can increase pressure in your arteries and speed up your heart rate. Mayo Clinic researchers reported in "Circulation" that excessive leptin predicts cardiovascular events, such as heart attack, stroke, artery narrowing and atrophy of your heart's main pumping chamber. Those who have the worst prognoses after such events usually have elevated leptin levels. The Iranian researchers reported that in experiments, leptin accelerated the formation of plaques in arteries, induced oxidative stress in the cells surrounding major organs, and stimulated the release of pro-inflammatory cells. By contrast, note the Mayo Clinic researchers, leptin may also protect against plaque formation. Plentiful leptin has been associated with fewer atherosclerotic lesions and better survival rates from cardiovascular disease, under certain conditions.

Leptin, Obesity and Heart Health

Another way leptin may affect your heart is through obesity. People who have leptin resistance don't benefit from its appetite-cancelling effects, and consequently they overeat. Moreover, they also don't burn more calories as their bodies sense excess stored energy. Excess leptin is also linked with obesity-related hypertension, according to the authors of a July 2007 article in the "Journal of the American Society of Hypertension." Authors of an "Endocrinology" article said that a high-fat diet leads to leptin resistance as it relates to activity in the brain, but simultaneously stimulates leptin action in heart muscle. This is a protective mechanism that attempts to shield your heart from too much fat being deposited despite your diet. The Mayo Clinic researchers explained the conflicting activity by saying that leptin both promotes and protects from heart disease, and these "opposing actions of leptin are maintained in balance under healthy conditions." However, under pathological conditions like obesity, the balance may shift toward the more negative effects.

Maximize Your Leptin Potential

You can improve the effectiveness and sensitive of your leptin by eating a healthy diet and losing weight, especially body fat. Exercising can also significantly shift the actions of leptin in your favor, as well as improve your insulin sensitivity, which also interacts with leptin. Arguably, one of the best things you can do to maximize the potential of your leptin is get enough sleep. Leptin is released by your fat cells, with peak expression occurring around 2 a.m. Getting too little sleep is associated with higher body mass index and can elevate another hormone, ghrelin, which increases your appetite.