Views: 11 Author: Site Editor Publish Time: 2019-05-12 Origin: Site
Appendix , not an useless organ
Medicine is not always respectful of human body. Consider how early surgeons were ruthless in their disregard for the integrity of human body: they drilled holes in the skull and bled boldly with leeches or scalpels. Until the end of the 19th century, this was the dominant practice in medicine. Even now, complete removal of some body organs, including the appendix, gallbladder, tonsils and uterus (usually after child-bearing age), is popular. Doctors will assure patients that they will be fine without them. There have been many seemingly solid reasons to do this, but is it true that there are no adverse consequences, or is there just a small effect? The arguments in favor of this theory are becoming increasingly weak.
Take the appendix for example. What many people learn in school is that the appendix sticks out like a pinky finger at the end of the colon, a useless vestige of evolution, like the tiny leg bones of some snakes. But Heather Smith, an evolutionary biologist and director of the anatomy lab at Midwestern University, says this view has been overthrown. In 2017, a study led by Smith evaluated 533 mammal species and found that multiple unrelated species had appendices. "This suggests that there are good reasons for living things to keep their appendix," she said.
The reason seems to have to do with the gut and immunity. Smith notes that the appendix either contains or is closely related to lymphoid tissue, which supports the immune system. A layer of bacteria which is beneficial to gut also lives in the human appendix, according to a study from Duke University. In a paper published in 2007, they suggested that the appendix was a "safe house" for these bacteria, and that when the intestinal microbiome was decimated by disease, the beneficial bacteria hiding in the appendix were the energy source of intestinal microbes. A study in 2011 provided ample evidence for this idea: people without an appendix are four times more likely to relapse after infection with c. difficile than people without an appendix. Clostridium difficile is a dangerous bacteria in the intestinal tract, and thrives when the good bacteria are absent.
The appendix affects the body, but there are cases that are opposite. A study published in October 2018 showed that misfolded alpha-synuclein, an abnormal protein found in the brain of patients with Parkinson's disease, can accumulate in the appendix. Interestingly, the study found that removing the appendix at a young age appears to have a protective effect against Parkinson's disease.
The value of tonsils and adenoids have also been recognized in recent studies. In a study published in June 2018, researchers surveyed 1.2 million Danish children to assess the long-term effects of removing or retaining these two organs. Five percent of these children had at least one of these organs removed by the age of nine. But 10-30 years of follow-up showed that people who had both organs removed were two to three times more likely to have upper respiratory problems and had higher rates of allergies and asthma than other children. It is important to note that these children, who had their tonsils removed to reduce some common infections (ear infections, sinusitis, laryngitis, sore throat), are now more susceptible to infection.
We know that the amygdala and adenoids' are the first line of defense against pathogens, 'said Sean Byars, the study's lead author and a senior fellow at the Melbourne School of Population and Global Health. These organs are most present in children and largely absent in adulthood. As a result, some argue that these organs are not important, but Byars points out: "there may be a reason they are the largest in children." Perhaps they boost growth, shape the immune system and have long-term effects.
Despite the size of his study, Byars says more researchers are required to follow up. After all, any treatment for children requires multiple confirmations. "Tonsillectomy and adenoidectomy are the most common procedures in children, and our study shows that it is more prudent to be conservative," he said.
Tonsillectomy rates have declined in the United States, especially since their peak in the mid-20th century. Surgeons are also less likely to recommend a hysterectomy. This suggests, perhaps, that the womb is not entirely useless after childbirth. There are less radical ways to deal with common problems such as uterine fibroids.
The paper is publicized in Scientific American