Tag Archives: lab

muscle

Scientists grow functioning human muscles from skin cells

muscle

Credit: Pixabay.

In a novel research project, bioengineers at Duke University demonstrated how to grow functioning human muscles from induced pluripotent stem cells. It’s the first time scientists have shown that it’s possible to grow human muscles essentially starting from scratch, all by coaxing skin cells to generate stem cells, which ultimately turned into muscle tissue.

Previously, the same team grew functioning human muscle — the kind that contracts in response to a stimulus such as an electrical signal — in culture, starting with pea-sized globs of muscle, sourced from human volunteers.

While the previous attempts grew new muscle from native muscle, the present work is far more sophisticated since the resulting tissue doesn’t depend on donated muscle. What’s more, the ability to generate muscles starting from non-muscle tissue helps scientists grow far more of these cells. Bearing this in mind, the new technique will prove far more useful as far as genome editing and cellular therapies go. It also makes it possible to tailor custom treatments for rare muscle disorders such as muscular dystrophies or test substances for new drug discovery.

Skin to muscle

Researchers have grown the first functioning human muscle tissue from skin cells reprogrammed into stem cells. Credit: Duke University.

Researchers have grown the first functioning human muscle tissue from skin cells reprogrammed into stem cells. Credit: Duke University.

It all starts from human induced pluripotent stem cells (iPSCs), which are adult non-muscle tissues, such as skin or blood, that have been reprogrammed to revert to a primordial state. Just like any stem cells, iPSCs can then be programmed to differentiate into any kind of tissue. In our case, scientists flood the iPSCs with a signaling molecule called Pax7 which triggers muscle formation out of the cells.

“Starting with pluripotent stem cells that are not muscle cells, but can become all existing cells in our body, allows us to grow an unlimited number of myogenic progenitor cells,” explained Nenad Bursac, professor of biomedical engineering at Duke University. “These progenitor cells resemble adult muscle stem cells called ‘satellite cells’ that can theoretically grow an entire muscle starting from a single cell.”

It sounds easy enough when reading this but the truth is it took Bursac and colleagues years of trial and error before they got it just right. One important breakthrough that enabled cell proliferation into functioning skeletal muscle was the introduction of a unique cell culture conditions and 3-D matrix, rather than having to rely on the 2-D culture approaches that are typically used. This way, cells can grow and develop much faster and longer.

Once the cells reached a critical threshold, the scientists stopped the flow of Pax7 and started giving the cells the support and nourishment they needed to fully mature.

After two to four weeks of 3-D culture, the muscle cells aggregated into muscle fibers that can contract and react to electrical pulses and biochemical signals just like natural muscles would in response to neuronal inputs.

The lab-grown muscle fibers were put to the test when they were implanted into adult mice. Small ‘windows’ grafted on the backs of the mice allowed the researchers to observe how the muscles they’ve grown behaved inside the rodents. The muscles survived and functioned for at least three weeks, during which it progressively integrated with native tissue through vascularization.

The resulting muscle, unfortunately, is not nearly as strong as native muscle tissue nor that grown from muscle biopsies for that matter. It makes up for it, however, in versatility and the ability to grow many more cels from a smaller starting batch than other methods, such as the biopsy one. What’s more, the team’s new muscle seems capable of supplying a special reservoir of cells that muscles can use to regenerate themselves following injury or exercise — an important hallmark of natural muscle. Biopsied muscle tissue, in contrast, produces a far less richer reservoir.

“The prospect of studying rare diseases is especially exciting for us,” said Bursac. “When a child’s muscles are already withering away from something like Duchenne muscular dystrophy, it would not be ethical to take muscle samples from them and do further damage. But with this technique, we can just take a small sample of non-muscle tissue, like skin or blood, revert the obtained cells to a pluripotent state, and eventually grow an endless amount of functioning muscle fibers to test.”

Findings appeared in the journal Nature Communications

A $550 handheld spectral analyzer could usher in new medical revolution

Hi-tech medical testing could be made much more accessible with this cheap hand-held device which attaches itself to a smartphone.

The spectral transmission-reflectance-intensity (TRI)-Analyzer attaches to a smartphone and analyzes patient blood, urine, or saliva samples as reliably as clinic-based instruments that cost thousands of dollars. Image credits: University of Illinois at Urbana-Champaign.

It’s capable of analyzing patient blood, urine, or saliva samples as reliably as standard lab equipment which costs thousands or tens of thousands of dollars each. It’s also small and can be easily moved around the hospital.

“Our TRI Analyzer is like the Swiss Army knife of biosensing,” said Professor Brian Cunningham, the Professor of Engineering and director of the Micro + Nanotechnology Lab at Illinois. “It’s capable of performing the three most common types of tests in medical diagnostics, so in practice, thousands of already-developed tests could be adapted to it.”

Cunningham and his colleagues detail their findings in a recently published paper. While not identical, their results were comparable to typical lab tests. The portable lab works by turning a smartphone’s camera into a high-performance spectrometer. It illuminates the sample with the phone’s internal white LED flash (or an inexpensive external diode). The light is then gathered into an optical fiber and sent down a diffraction grating, into the phone’s camera. All of this is arranged into a 3D printed plastic structure. Due to this simple, scalable structure, the device can also analyze several samples at once.

“Our Analyzer can scan many tests in a sequence by swiping the cartridge past the readout head, in a similar manner to the way magnetic strip credit cards are swiped,” said Long.

For now, they used it to conduct two tests: a biomarker associated with pre-term birth in pregnant women and the PKU test for newborns to indirectly assess enzymes associated with normal growth and development. Researchers say it could be used for a wide array of other tests, including a wide variety of proteins and antibodies in the blood. Basically, like any light spectrometer, it’s able to detect anything that causes a change in the color or light output of the sample.

It’s not just medical applications either — the device could be used in animal health, environmental monitoring, drug testing, manufacturing quality control, and food safety. The technology has been patented and is available for license.

Journal Reference: Kenneth D. Long, Elizabeth V. Woodburn, Huy M. Le, Utsav K. Shah, Steven S. Lumett and Brian T. Cunningham — Multimode smartphone biosensing: the transmission, reflection, and intensity spectral (TRI)-analyzer. DOI:10.1039/C7LC00633K

Mouse pups born from eggs released by lab-grown ovaries. Credit: O. Hikabe et. al.

Mouse eggs engineered entirely in the lab for the first time — later lead to healthy adults

Mouse pups born from eggs released by lab-grown ovaries. Credit: O. Hikabe et. al.

Mouse pups born from eggs released by lab-grown ovaries. Credit: O. Hikabe et. al.

A paper that has been met by everyone in the field with cheerful enthusiasm describes how the authors grew mice eggs from the ground up, starting from stem cells. The eggs were then fertilized with sperm and implanted in foster mothers. Though the success rate was less than 1%, some of the embryos grew into healthy pups and later into adults with no sign of dysfunctionality. The implications for fertility, but also the prospect of designer babies, are staggering.

From cell to egg to living mammal

The landmark procedure was performed by Katsuhiko Hayashi and colleagues at Kyoto University in Japan and took a decade to shape. At first, they started by coaxing pluripotent stem cells — cells that resemble stem cells and which theoretically can differentiate into any kind of cell in the body — to turn into egg and sperm cells.

In 2012, the Japanese researchers showed they could make fertile eggs from both mouse embryonic stem (ES) cells and induced pluripotent stem cells (iPS). While these iPSCs are similar to embryonic stem cells, the key difference is that they can be made from any cells from the host, like the skin. Pluripotency implies the capacity for stem cells to become a number of different cell types, but that does not necessarily provide the ability to develop an entire organism.

The discovery of induced pluripotent cells is one of the most important breakthroughs in biology because it means that you can now grow an entire liver or kidney that is biocompatible with the patient. In this case, the donor is the patient himself and millions of lives could be saved in the future once scientists get the knack of growing whole, functioning organs in the dish.

But going back to our mice and eggs, it was only this summer that Hayashi and colleagues fitted one of the last pieces of their jigsaw puzzle when they grew mouse ovaries in the lab, then used them to produce fertile eggs.

In total, around 50 eggs were produced, granted many presented chromosomal abnormalities. Still, 75% of the eggs had the correct number of chromosomes and these were mixed with sperm to produce 300-celled embryos.

The embryos were then implanted into foster mothers, but only 11 or 3% grew into full-term pups compared to 62%, in the case of eggs taken from adult mice and fertilized in vitro. The pups that did survive, though, grew into functioning adults.

“This is truly amazing,” says Jacob Hanna, a stem cell biologist at the Weizmann Institute of Science in Rehovot, Israel.  “To be able to make robust and functional mouse oocytes over and over again entirely in a dish, and see the entire process without the ‘black box’ of having to do any of the steps in host animals, is most exciting.”

“Parts of this work were done before — here they are put together in completeness. It’s impressive that they got pups that way,” says Dieter Egli, a stem cell biologist at the New York Stem Cell Foundation Research Institute.

The low success rate means we won’t be seeing human babies born this way anytime soon, but the paper demonstrated a way for infertile women to have their own babies. Another more ethically challenged pathway is that we could one day use this method to make designer babies starting from nothing but a few skin cells, with specific genetic alterations using a tool such as CRISPR-CAS9.

Both scenarios are very far away from becoming reality. The possibilities they entertain can only boggle the mind, though.

urine test

Cheap home urine test scans for diseases

urine test

Credit: YouTube

Stanford University researchers have developed a new low-cost tech that diagnoses diseases from a simple urine sample. The setup is made of a plastic-based lab-on-chip that does the actual chemical analysis and a frame where a dipstick and mobile phone can be placed. The latter is where the user gets his test results back, all from the comfort of his home.

Not your regular ‘toaster’

The urinary dipstick has been one of doctors’ most trusted assets for at least 60 years, used to determine pathological changes in a patient’s urine.This simple, yet powerful test consists of a paper strip with 10 square pads which change colour based on chemical markers. Based on how the paper pads change colour, you can measure levels of glucose, blood, protein and other chemicals, then deduce what kind of disease, if any, the patient is suffering from. These can be faulty, though, and most of the time serve only as a preliminary test before a barrage of “more serious” lab examinations.

“You think it’s easy – you just dip the stick in urine and look for the color change, but there are things that can go wrong,” said Audrey (Ellerbee) Bowden, assistant professor of electrical engineering at Stanford. “Doctors don’t end up trusting those results as accurate.”

The goal of the Stanford researchers was to democratize the dipstick and create a tech that can analyze urine samples from anywhere — all accurately enough to be trusted by doctors who remotely receive the patient’s report.

Because the dipstick needs consistent lighting conditions, the researchers first started with a black box made out of interlocking parts. This makes it easy to assemble and transport.

Next, a volume-control system was made to load the urine into the dipstick without having to worry if there’s too little or too much of it. A dropper is used to squeeze urine into the first compartment, which fills the channel in the second layer and the ten square holes in the third layer.

Finally, a smartphone is placed over an opening above the dipstick. The phone’s camera controlled via a custom software then focuses on each coloured pad. In the future, the team hopes to develop a custom app that not only analyzes each pad but automatically sends a report to the patient’s doctor.

Now, this sort of cheap device won’t replace lab tests, but it should drastically cut down man-hours and lab procedures. It might also uncover a disease earlier since people are more comfortable making the test at home instead of going to a hospital.

“[…] it is going to make diagnoses of current diseases more accurate in the hands of users,” said co-researcher Gennifer Smith, a Ph.D. student in the department of electrical engineering.

“There are definitely other aspects of urinalysis that we are investigating. There are extensions of the technology that can move more towards making this a full replacement of lab tests. We are thinking about that,” she added.

“It’s such a hassle to go into the doctor’s office for such a simple test,” said Smith. “This device can remove the burden in developed countries and in facilities where they don’t have the resources to do these tests.”