Tag Archives: underrated organs

Vetting the Spleen: Is it a blood filter or something more?

[Ultrasound of a spleen by Nevit Dilmen via Wikimedia Commons & CC 2.0] 

Blood moves fast.  It only takes about 20 seconds for a red blood cell  to make a full circuit through your entire body, and your blood makes that journey thousands of times each day.

The speed of the blood stream is a challenge for scientists who study how the body copes with invading bacteria. Normally, the bloodstream is devoid of microbial interlopers, but when bacteria do break into the blood stream, they can be extremely dangerous. Sepsis, for example, occurs when the immune system tries to fight off a large number of blood-invading bacteria. And sepsis kills up to half of the people who develop it, according to the NIH

So when bacteria find their way into blood, your body wants to take them out ASAP.  Blood-filtering organs like the liver, the kidneys, and the spleen have dedicated local immune cell task forces that help kill microbes, and of course, blood itself has loads of white blood cells on patrol.

But platelets–the globs of gunk that form scabs on wounds–also trap bacteria. When the bacteria are whizzing through the bloodstream, sometimes they collide with a platelet and get stuck to it. But according to a recent study in Cell Host and Microbe,  getting stuck to a platelet doesn’t kill the bacteria. 

Instead, the platelets carry their trapped bacteria through the bloodstream until they wash up at the spleen, says the study’s senior co-author Admar Verschoor from University of Lubeck in Germany.

Continue reading “Vetting the Spleen: Is it a blood filter or something more?” »

Why You Can Blame Your Metabolism on Liver Proteomics Instead of Your Genes

Blaming things on genetics–everything from lateness to diet quirks–is wildly popular these days. However, DNA’s role in your body’s overall destiny has been greatly exaggerated. Sure, DNA is the “master blueprint”, but any one gene from that blueprint can contain instructions for making hundreds or thousands of tiny cell parts. And even so, there are plenty of cell parts that defy the master template.

Proteins–tiny biological machines made from proteins that you eat– are key players in pretty much every biological process that happens. Yet, their behavior remains almost impossible to decipher. Scientists have gotten pretty good at decoding genes and RNA snippets, and tracking a single type of protein is pretty doable. Also, since RNA snippets are templates for building proteins, scientists often use RNA data to estimate the total number of proteins. But there are thousands of different protein forms in every cell; tracking all of them at once remains basically impossible.

However, variations in those proteins can make an enormous difference in processes like weight gain. And according to a new study, our most-used method for estimating protein numbers–counting the RNAs–only works about 30% of the time. 

As in, according to science’s latest numbers, at least 2/3rds of all “genetic bad luck” happens outside of genes. 

Continue reading “Why You Can Blame Your Metabolism on Liver Proteomics Instead of Your Genes” »

Inside the Pancreas: How Beta Cells Change as We Age

[A diabetic supply kit, complete with a knitted pouch that’s shaped like a pancreas. Photo by Erin Stevenson O’Connor via Flickr and Creative Commons.] 

The box arrived around 5:00 pm. Many of Efsun Arda’s colleagues were already heading home for Thanksgiving, but Arda had work to do. As a post-doc in Seung Kim’s lab at Stanford, Arda studies one of the body’s most unknowable vital organs– the pancreas.

Although the pancreas plays a crucial role in diabetes–which impacts almost 1 in 10 Americans, according to the CDC–and although pancreatic cancer is extremely lethal, the pancreas remains largely a mystery, Kim and Arda say.

(A quick Google Scholar search turned up 20,500 papers mentioning the pancreas in 2016 so far, but that’s a stark contrast to the 124,000 papers for “liver” and 113,000 for “kidney”.) 

Much of what doctors do know about the pancreas comes from inference based on physiological and blood chemistry studies.

Collecting pancreas samples from living people is extremely risky and highly impractical. The pancreas itself is a large gland, full of active enzymes, nestled in a tough-to-reach spot behind the stomach. The enzymes inside the pancreas itself are “like a pack of wolves” Kim says; the slightest damage will cause the organ to start digesting itself, which would likely kill the patient.

Consequently, most studies that peek under the pancreas’ hood rely on cadavers.  Continue reading “Inside the Pancreas: How Beta Cells Change as We Age” »