In people, this can lead to severe complications that include liver damage, kidney failure and detachment of the placenta. Natterson-Horowitz is now turning her attention to another problem that giraffes seem to have solved: high blood pressure during pregnancy, a condition known as preeclampsia. Cardiovascular researchers are trying to understand how giraffes minimize this problem.Ĭ. Lifting it again should cause a corresponding drop in cranial blood pressure-an extreme version of what often happens when a person stands up suddenly. The great height of giraffes poses a problem when they drink: Lowering the head so far should dramatically increase blood pressure to the head. “All you have to do is look at a picture of a fleeing giraffe,” Natterson-Horowitz says, “and you realize that the giraffe has solved the problem.” (Neither of her studies has been published yet.) This allows the heart to pump more blood with each stroke, allowing a giraffe to run hard despite its thicker heart muscle. And in March 2021, another research group reported giraffe-specific variants in genes involved in fibrosis.Īnd the giraffe has another trick to avoid heart failure: The electrical rhythm of its heart differs from that of other mammals so that the ventricular-filling phase of the heartbeat is extended, Natterson-Horowitz found. In keeping with that find, other researchers who examined the giraffe genome in 2016 found several giraffe-specific gene variants related to cardiovascular development and maintenance of blood pressure and circulation. The researchers also found that giraffes have mutations in five genes related to fibrosis. When cardiologist and evolutionary biologist Barbara Natterson-Horowitz of Harvard and UCLA examined giraffes’ hearts, she and her student found that their left ventricles did get thicker, but without the stiffening, or fibrosis, that would occur in people. This type of heart failure is responsible for nearly half of the 6.2 million heart failure cases in the US today. The left ventricle of the heart becomes stiffer and less able to fill again after each stroke, leading to a disease known as diastolic heart failure, characterized by fatigue, shortness of breath and reduced ability to exercise. In people, chronic high blood pressure causes a thickening of the heart muscles. It doesn’t faze the giraffes, but a pressure like that would cause all sorts of problems for people, from heart failure to kidney failure to swollen ankles and legs. To have a blood pressure of 110/70 at the brain - about normal for a large mammal - giraffes need a blood pressure at the heart of about 220/180. Giraffes have sky-high blood pressure because of their sky-high heads that, in adults, rise about six meters above the ground - a long, long way for a heart to pump blood against gravity. Their solutions, only partly understood by scientists so far, involve pressurized organs, altered heart rhythms, blood storage - and the biological equivalent of support stockings. Giraffes, it turns out, have solved a problem that kills millions of people every year: high blood pressure.
But to a cardiovascular physiologist, there’s even more to love. Trauma and surgery where the lymph nodes are removed, radiography and chronic infection which can result in fibrosis and eventual lymphatic obstruction.To most people, giraffes are merely adorable, long-necked animals that rank near the top of a zoo visit or a photo-safari bucket list.
Secondary Lymphedema is most commonly caused when lymph vessels are damaged or lymph nodes are removed and there can be a variety of causes including malignancy in breast cancer, where the lymphatic channels are compressed or metastasis can occur in the lymph nodes.
More common in younger women, Primary Lymphedema can start near birth, around puberty or later in life.įor both upper and lower extremities Primary Lymphedema is estimated to affect 1 million individuals and Secondary Lymphedema about 2 million individuals in the USA. Primary Lymphedema develops when lymphatic vessels are missing or impaired.
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