#cryopreserved

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The Smithsonian’s National Zoo and Conservation Biology Institute and the Nashville Zoo are pleased to announce the birth of a male clouded leopard on March 1, 2017 from an artificial insemination (AI) procedure using frozen/thawed semen. This accomplishment is a first for this species and a giant step for global conservation efforts.

“This cub, the first clouded leopard offspring produced with cryopreserved semen, is a symbol of how zoos and scientists can come together to make positive change for animals and preserving global biodiversity,” said Adrienne Crosier, biologist at the Smithsonian Conservation Biology Institute. “Collaboration is the key to conservation of clouded leopards, along with so many other rare and endangered species we care for and study.”

The Smithsonian’s National Zoo and Conservation Biology Institute and Nashville Zoo have a long history of working together on clouded leopard conservation. Since 2000, they have collaborated with Point Defiance Zoo and Thailand’s Zoological Park Organization to form the Clouded Leopard Consortium and develop breeding programs as well as field monitoring projects for clouded leopards in Thailand. Because the captive clouded leopard population is not self-sustaining, it necessitates the need for intensive reproductive management techniques to maintaining captive populations not only in the U.S. but also throughout the world.

“This is an enormous accomplishment for both Nashville Zoo and the team at the Smithsonian,” said Dr. Heather Robertson, Director of Veterinary Services at the Zoo. “It means we can collect and preserve semen from clouded leopard populations around the globe and improve pregnancy outcomes from AI procedures in this species.”

Dr. Robertson and Nashville Zoo Associate Veterinarian Dr. Margarita Woc Colburn used hormones to induce ovulation in a female named Tula living at Nashville Zoo. The Smithsonian’s research staff, Crosier, Ph.D., Pierre Comizzoli, D.V.M., Ph.D., and Diana Koester, Ph.D, collected semen a week earlier from a male named Hannibal at Smithsonian’s National Zoo. The team used a new technique depositing a very small volume of semen into the oviduct where the eggs normally rest after ovulation.

After birth, the cub was removed for examination and will be hand-raised by keepers to ensure survival and well-being. This process also lowers animal stress for future hands-on care. The cub will stay at Nashville Zoo with plans to eventually introduce him to a potential mate.

The first successful clouded leopard AI was performed at Nashville Zoo in 1992 by Smithsonian scientist JoGayle Howard and Nashville Zoo President Rick Schwartz. In 2015, Comizzoli contributed to a successful birth using cooled semen and the new AI technique at the Khao Khew Open Zoo in Thailand.

Clouded leopards are among the rarest of the world’s cat species and one of the most secretive. Due to limited knowledge of this species, they have proved difficult to breed in captivity. They are sensitive to auditory and visual disturbances, increasing the stress levels during captive breeding programs – leading facilities, such as Nashville Zoo, to work with artificial insemination specialists to increase the size and diversity of the captive bred population.

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This article and images was originally posted on nationalzoo.si.edu

via Newsroom |First Clouded Leopard Cub Produced with Cryopreserved Semen

Researchers have developed a technique that allows them to rapidly thaw cryopreserved human and pig samples without damaging the tissue – a development that could help get rid of organ transplant waiting lists.

Cryopreservation is the ability to preserve tissues at liquid nitrogen temperatures for long periods of time and bring them back without damage, and it’s something scientists have been dreaming about achieving with large tissue samples and organs for decades.

Not only for the life-extending applications we’ve read about in sci-fi novels, but, more feasibly, because the technology could allow hospitals to safely store organs for long periods of time.

Right now, 22 people die in the US each day on average while waiting for an organ transplant. One of the biggest challenges isn’t organ shortages – it’s that organs can’t stay ‘on ice’ longer than a few hours without being irrevocably damaged.

That means even when there are enough organs being donated, there’s still the huge logistical problem in finding a matching recipient and getting the organs to them fast enough.

Already it’s estimated that more than 60 percent of the heart and lungs donated for transplantation each year are thrown out, because they can’t be kept on ice more than four hours, and can’t make it to a patient who needs them in that time.

“If only half of these discarded organs were transplanted, then it has been estimated that wait lists for these organs could be extinguished within two to three years,” the researchers, led by John Bischof from the University of Minnesota, write in Science Translational Medicine.

A better solution could be cryopreservation – keeping tissue stored at temperatures around -80 to -190 degrees Celsius (-112 to -310 degrees Fahrenheit).

One of the leading cryopreservation techniques is vitrification – which involves super-cooling biological samples to a glassy state at around -160 degrees Celsius (-256 degrees Fahrenheit). In fact, vitrification is already being used on human brains by cryonics companies such as Alcor.

Through vitrification, organs could be stored for years and potentially even longer, which would mean doctors could build up a bank of available organs and make it a lot easier for anyone who needs a heart or lung to find one straight away.

But while we’ve managed to get the cooling part down, the problem is that the thawing process can cause ice crystals to form and damage tissue, and potentially even crack it during the thawing process.

In the past, researchers have successfully shown that thawing can work in small tissue samples up to around 1 mL in volume. But as tissue gets larger, and approaches the size of entire human organs, the current leading technique of convection – slow warming over ice – doesn’t work.

That could be about to change, with the Minnesota team announcing the development of a new technique that’s allowed them to rapidly rewarm cryogenically treated human and pig samples without damaging delicate frozen tissues.

“This is the first time that anyone has been able to scale up to a larger biological system and demonstrate successful, fast, and uniform warming of hundreds of degrees Celsius per minute of preserved tissue without damaging the tissue,” said Bischof.

Instead of using convection, the team used nanoparticles to heat tissues at the same rate all at once, which means ice crystals can’t form, so they don’t get damaged.

manuchehrabadi1HR Manuchehrabadi et al., Science Translational Medicine (2017)

To do this, the researchers mixed silica-coated iron oxide nanoparticles into a solution and generated uniform heat by applying an external magnetic field.

They then warmed up several human and pig tissue samples ranging between 1 and 50 mL, using either their new nanowarming technique and traditional slow warming over ice.

Each time, the tissues warmed up with nanoparticles displayed no signs of harm, unlike the control samples.

You can see the comparison below, with the nanowarming group on the left of the red line, and the control groups on the right:

manuchehrabadi2HR Manuchehrabadi et al., Science Translational Medicine (2017)

Afterwards, they were able to successfully wash the nanoparticles away from the sample after thawing.

The team also tested out the heating in an 80 mL system – without tissue this time – and showed that it achieved the same critical warming rates as in the smaller sample sizes, suggesting that the technique is scalable.

“In short, nanowarming matches fast convective warming viability and biomechanical testing at 1 mL, is superior to convective warming at 50 mL, and is physically scalable to 80-mL systems,” the team writes.

“In the future, we believe that nanowarming can be applied to larger tissues and organs up to volumes of 1 litre and possibly beyond.”

You can see a video of tissue being thawed out in less than a minute below:

Video via

The team admits that larger tissue – and even whole organs – will need to have the nanoparticles injected into them, rather than just sitting around them, to achieve the same uniform heating, but it’s something they want to try next.

It’s important to note that the team hasn’t successfully shown that their technique actually works on organs, which are made up of complex arrangements of multiple tissue types.

That’s something that will require a lot of optimisation and tweaking, so we’re a long way off being able to bring organs back from cryopreservation. But it’s the first time we’ve seen such large volumes of tissue successfully be thawed from a cryopreserved state, and that’s pretty exciting.

The research has been published in Science Translational Medicine.

This article and images was originally posted on ScienceAlert

by FIONA MACDONALD

Tag: #cryopreserved

First Clouded Leopard Cub Produced with Cryopreserved Semen

Scientists have found a way to rapidly thaw cryopreserved tissue without damage

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