Stem cells could help mend a broken heart, but they’ve got to mature

Ashley Fong, University of California, Irvine

Heart disease is the number one cause of death in the US. The most common type is coronary heart disease, which occurs when there’s a buildup of plaque within the heart’s blood vessels. Smoking, diabetes, obesity and high blood pressure can all contribute. When there’s a complete blockage – a heart attack – a large portion of the heart muscle dies. The heart responds by creating scar tissue, eventually leading to heart failure – the heart muscle just can’t pump enough blood to the rest of the body.

Blood vessels are blocked with plaque in atherosclerosis.
NIH: National Heart, Lung and Blood Institute

Currently, the only treatment options for damaged heart muscle are surgery, if possible, and for the worst cases, a whole heart transplantation. But there’s a huge shortage of organs for transplantation, and for this reason, we need to find new strategies to treat heart disease.

Stem cells have great potential to fill this void. They’re a unique type of cell that starts out unspecialized but can multiply and turn into specialized cells of the adult body – for instance, brain cells or heart muscle cells, officially called cardiomyocytes.

A colony of induced pluripotent stem cells under the microscope.
Ashley Fong, CC BY-ND

Stem cells may be useful in tissue engineering therapies; researchers build tissues from them in the lab to transplant and replace damaged muscle. They could potentially be used in cellular therapies; researchers inject the heart cells into the heart and allow for regeneration. Right now, one ongoing clinical trial injects a heart attack patient’s own heart stem cells back into the patient’s heart to decrease scar size and promote heart regeneration. In addition, stem cells can also be used as a drug-screening platform in order to find new drugs to treat heart disease.

These options rely on turning stem cells into heart muscle cells – but even once they differentiate, the heart cells remain immature. They’re not fully developed, having characteristics you’d find in a fetus, not an adult. To advance these possible therapies, we need ways to take these heart muscle cells one step further, to maturity. I’m studying how the heart’s natural environment affects that maturation process. I focus on how the extracellular matrix, or scaffold, of the heart affects maturation. The overall goal is to find a way to create from stem cells fully functioning, mature heart cells that can be safely and effectively used for transplantation therapies and drug screening applications.

The author explains her research as part of the UC Grad Slam 2015 at 29:23.

Adult cells to stem cells to immature heart cells

There are many kinds of naturally occurring stem cells, but I work with a type that can be made from the adult body. For example, I can take your regular skin cell or blood cell and transform it in the lab into a stem cell by using viruses to introduce stem cell genes into it. The official name for what I wind up with after three or four weeks is “induced pluripotent stem cells.”

This new stem cell has the unique ability to replicate and turn into almost any cell of the adult body. Since they can be made from a patient’s own cells, the induced pluripotent stem cells retain the patient’s specific genetic information. That’s a big benefit when transplanting the cells – there’s no need for immunosuppression to avoid rejection of the new tissue by the patient’s body. It also allows a patient’s specific disease to be modeled in the lab, in hopes of finding a customized drug or therapy for this individual’s particular disease. This situation is sometimes called a “clinical trial in a dish.”

The author feeding her cells in the lab.
Kimberly Lim, CC BY-ND

After years of hard work, I was finally successful at manipulating the stem cells into heart muscle cells in the lab. I had to find the perfect stem cell line and protocol to use, which required lots of trial and error. It was very exciting to finally see the beating heart muscle cells in my petri dish!

Immature cardiomyocytes beating spontaneously in a petri dish.

But the cells’ ability to beat on their own actually demonstrates that they’re immature, and thus shouldn’t be used in treatment and drug screening. They spontaneously beat inappropriately. They don’t have the proper machinery to contract with the necessary force. These actions could have dangerous consequences if we were to rely on immature cells in a patient’s heart. Mature cardiomyocytes beat in response to a signal from the heart’s pacemaker cells, avoiding the safety risk of arrhythmia. And mature cells are strong enough to pump blood throughout the body.

So I need to figure out how to mature these cells.

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Poo transplants can eliminate two superbugs from the gut: mice study

Eliza Berlage, The Conversation

Two of the most common antibiotic-resistant bacteria circulating in hospitals can be wiped out by transplanting faeces from a healthy animal into the gut of an infected one, a study on mice has found.

The study, published today in the journal PLOS Pathogens examined two antibiotic resistant bugs: vancomycin-resistant Enterococcus faecium (VRE) and multi-drug resistant Klebsiella pneumonia.

A research team led by Eric Pamer, Chief of Infectious Diseases at Memorial Sloan-Kettering Cancer Centre in New York found that the bacteria can share the same location in the gut, but that “transplantation of a diverse faecal microbiota eliminates both VRE and K. pneumoniae from the gut.”

Mark Morrison, Chair of Microbial Biology and Metagenomics at the University of Queensland said the study revealed some new insights into how these bacteria colonise the gastrointestinal tract.

“Using a dose of other gut microbes through faecal transplantation appears to effectively displace these antibiotic resistant microbes, which warrants further investigation,” said Professor Morrison, who was not involved in the study.

Previous studies have found that the gut’s protective mucus layer that normally guards against microbes can thin out when gut microbiota are not well balanced.

Morrison said more work was needed before the findings could be applied to humans infected with these bacteria.

“In addition to the potential of faecal transplants, we need to ensure the prudent and effective use of existing antibiotics, and better monitor and detect these bugs. We must find new solutions to inhibit existing superbugs and develop strategies that minimise, or even eliminate, the potential for development of new superbugs,” he said.

The Conversation

Eliza Berlage is Editor at The Conversation

This article was originally published on The Conversation. Read the original article.

 

 

Article republished in full with the generous permission of The Conversation.

Photo Credit: Rick Eh/flickr

Exploding 5 Myths About “Female Viagra”

With all the buzz in the news and on social media about the recently approved “female Viagra” drug, officially named Addyi, which will be going on the market in October, we ran across a great article over on CNN Health that helps to explode all of the myths.

Up first, turns out it’s not like Viagra at all:

While people are calling Addyi the “female Viagra,” it doesn’t really work that way. Viagra eliminates a physical problem for men. Men take it to get and keep an erection. They pop it before they want to have sex. Addyi doesn’t treat a physical problem for women — instead it targets the chemicals in their brain and it improves, in at least 37% of the women who take it, their sense of desire for their romantic partner. Women have to take Addyi every night.

Viagra works by dilating specific blood vessels which increases blood flow to the penis, a very different process altogether.

Will it be a cure for women who just aren’t that into sex? On the next page we answer that…

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To Prevent Cavities, Swish With These Bacteria

What??? Yes, you read that right, and researchers at the University of Florida say that you can fight the bacteria that causes cavities with… the same bacteria genetically modified not to cause cavities… Confused yet?  Here’s what the informative article on the UF Dental College website reports:

Fighting tooth decay could someday be as simple as using a mouth rinse, thanks to a University of Florida researcher who has genetically altered the bacterium known to cause tooth decay into a form that may permanently prevent the disease.

Ok, but that’s not the really weird part. We’ll clue you in on that on the next page…

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