Tag: Stem cells

A Functional, Beating Hearts Will Soon Be 3D-Printed Using Patients’ Own Cells

Inside a lab that will open in a couple of months in Chicago, a biotech startup will soon begin perfecting the process of 3D-printing human hearts that could eventually be used in transplants.

The process combines several steps that have been developed by various researchers in university labs. First, a patient’s heart will be scanned using an MRI machine to create a digital image of the heart’s shape and size.

Next, doctors will take a blood sample. Using techniques that have been developed over the last decade, the blood cells will be converted into stem cells–and then converted a second time into heart cells.

Those new heart cells will be combined with nutrients in a hydrogel to make a “bio-ink” that can be used in a specialized 3D printer.

Printing one layer at a time, with a biodegradable scaffolding to keep everything in place, the cells can be formed into the exact shape of the patient’s original heart.

The new heart will be moved to a bioreactor to strengthen it. Amazingly, new heart cells outside a body will begin to self-assemble.

When the heart is strong enough, technicians will raise the temperature to melt the scaffolding around the cells.




The new heart can then be transplanted–and because it is the exact size of a patient’s original heart, and made from the patient’s own cells, it has a greater chance of success than a traditional transplant.

In studies, other researchers have successfully transplanted stem cells in both humans and animals without the need for anti-rejection drugs.

Most people who receive heart transplants now don’t live more than a decade. Their body may reject the organ directly.

The drugs they take to suppress their immune system–in an attempt to prevent the body from rejecting the foreign organ–may also make them unable to fight off another disease, such as cancer.

The Biolife4D heart, in contrast, won’t require patients to take immunosuppressant drugs since it is an exact genetic match.

The company isn’t the only startup in the space. A startup called Prellis Biologics, for example, has another printing process that is optimized for speed, and that includes blood vessels.

A company called Organovo already makes 3D printed human tissue for drug discovery. But Biolife4D may be the only startup to use equity crowdfunding.

The company has opened up investment to the public. “We wanted to make [the investment opportunity] available to everybody, not just wealthy people on Wall Street,” Morris says.

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Scientists Produce Healthy Mice Born To Same-Sex Parents Using Stem Cells And Gene Editing

Scientists have been able to breed mice with same-sex parents using a breakthrough technique involving stem cells and gene editing.

Researchers at the Chinese Academy of Sciences have produced healthy mice with two mothers, who were then able to go on to reproduce themselves.

Mice with two fathers were also born during the study, but only survived for a matter of hours.

Using female same-sex parents, the scientists were able to produce a total of 29 live mice from 210 embryos.

All these offspring were normal, lived to adulthood, and were able to give birth to offspring of their own.

The study, published in scientific journal Cell Stem Cell, examined why same-sex mammals are not typically able to reproduce, suggesting stem cells and targeted gene editing can make the process easier.

We were interested in the question of why mammals can only undergo sexual reproduction,” the study’s co-senior author Dr Qi Zhou said.

We have made several findings in the past by combining reproduction and regeneration, so we tried to find out whether more normal mice with two female parents, or even mice with two male parents, could be produced using haploid embryonic stem cells with gene deletions.




While some species of reptiles, amphibians and fish can change gender in order to reproduce or exist as both male and female at the same time, same-sex reproduction for mammals is a more difficult proposition, Dr Zhou said.

He said in mammals, certain maternal or paternal genes are shut off during the development of sperm and egg cells, meaning offspring that do not receive genetic material from both a mother and father might experience developmental abnormalities.

By deleting imprinted genes from immature eggs, researchers have in the past been able to produce mice with two mothers, although most still displayed genetic defects.

To produce healthy bi-maternal mice, Dr Zhou, his co-senior authors Dr Baoyang Hu and Dr Wei Li, and their colleagues used haploid embryonic stem cells (ESCs), containing half the normal number of chromosomes and DNA from each parent.

We found in this study that haploid ESCs were more similar to primordial germ cells, the precursors of eggs and sperm,” Dr Hu said. “The genomic imprinting that’s found in gametes was ‘erased’.

Alongside the 29 healthy mice produced by same-sex female parents, a dozen mice were also born to two male parents during the course of the study.

However, the process of creating mice from same-sex male parents, which involves modifying a larger amounts of genes and inserting fertilised embryos into surrogate mothers, is more complicated.

All offspring from two males born during the study died after less than 48 hours, although scientists believe they can improve the process in future tests.

This research shows us what’s possible,” Dr Li said. “We saw that the defects in bi-maternal mice can be eliminated and that bi-paternal reproduction barriers in mammals can also be crossed through imprinting modification.

We also revealed some of the most important imprinted regions that hinder the development of mice with same-sex parents, which are also interesting for studying genomic imprinting and animal cloning.

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Stem Cell Technique Could Lead To New Ways To Treat Male Infertility

Scientists have created immature sperm cells in a laboratory dish and injected them into eggs to produce mouse offspring.

The Chinese researchers say their stem cell technique could pave the way for new treatments for male infertility.

British experts have called for the results to be independently verified and pointed out that any practical application is likely to be a long way off.

The mouse cells produced were technically “spermatids” – undeveloped sperm that lack tails and cannot swim.




Yet when they were injected into mouse eggs, mimicking a common IVF technique called Icsi (intracytoplasmic sperm injection), they delivered viable embryos and healthy, fertile babies.

In the UK, using spermatids in the same way to produce a pregnancy would be illegal.

Dr Jiahao Sha, from Nanjing Medical University who co-led the research, which was reported in the peer-reviewed journal Cell Stem Cell, said: “If proven to be safe and effective in humans, our platform could potentially generate fully functional sperm for artificial insemination or in-vitro fertilisation techniques.

Because currently available treatments do not work for many couples, we hope that our approach could substantially improve success rates for male infertility.

The scientists began with stem cells taken from mouse embryos which were exposed to a carefully mixed cocktail of chemicals. This triggered their transformation into primordial germ cells, the first step on the developmental path to becoming sperm.

Next, the germ cells were exposed to testicular cells and testosterone in an attempt to mimic the natural environment of the testes.

When the resulting spermatids were injected into mouse eggs, they proved capable of producing embryos that developed normally.

Infertility affects around 15% of couples and can be traced to the man in about a third of cases.

A major cause of male infertility is the failure of pre-cursor cells in the testes to undergo a special type of cell division called meiosis.

In 2014, a team of distinguished reproductive biologists writing in the journal Cell proposed a set of “gold standard” criteria to prove that all the essential steps of meiosis have taken place in artificially created eggs or sperm.

They included showing evidence of correct DNA content in the cell nucleus at specific meiotic stages, normal chromosome number and organisation, and the ability of the engineered cells to produce viable offspring.

Scientists in the UK praised the “mammoth” achievement of their Chinese colleagues – but said there were still many obstacles to be overcome before sperm-like cells grown in the laboratory could be of use to infertile men.

Professor Richard Sharpe, from the Medical Research Council Centre for Reproductive Health at the University of Edinburgh, said safety was a major issue.

Bear in mind that if germ cells do not format their DNA correctly, it may not only affect the resulting individual but might also affect the next generation,” he warned.

Allan Pacey, Professor of Andrology at the University of Sheffield, said the study was an “interesting step forward”, but added: “In spite of these encouraging results, we are still some way from immediately applying this technique as a potential cure for human male infertility.”

It remains to be seen if this technique could be applied in humans to create sperm-like cells that might be useable in IVF.

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Pass it on: New Scientist