testicles

Tiny lab-grown testicles look remarkably like the real thing under the microscope

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The first-ever 3D model of testicles, made using mouse cells, could improve our understanding of sex development disorders and male infertility.

Black and white microscope image of an artificial testicle which looks like a bundle of noodles

The new model testicles could have important health implications, the researchers who made them say. One of the artificial testicles is pictured above in high detail under the microscope after 14 days of development. 

For the first time, scientists have grown three-dimensional, miniature versions of testicles in the lab, using mouse cells. 

The lab-grown testicles survived in a dish for up to nine weeks and closely resembled natural mouse testicles, even developing tubelike structures equivalent to those that produce sperm in the testes of mice and humans. The cells within the model testicles also expressed genes similar to those that are active in regular mouse testicles. 

The replica testicles are so-called organoids — self-organizing 3D structures that are grown to resemble full-size tissues in the body. Scientists have created organoids of many organs, including the human heart and brain, with the aim of better capturing the complexities of these tissues in 3D and in a way that represents human biology better than animal models do. Organoids are usually created by coaxing stem cells to develop into tissue-like structures by exposing them to specialized growth chemicals in a dish. 

The researchers behind the new testicle organoids described their achievement in a paper published Jan. 12 in the International Journal of Biological Sciences. They say the organoids could help improve our understanding of the testicles, or testes, whose main job is to produce the male sex hormone testosterone and sperm needed for reproduction. As such, the organoids could also provide valuable insight into conditions that are linked to improper testicle functioning, such as sex development disorders and male infertility, the scientists say.  

“Once we have an in vitro [petri dish] cellular model of the testis, we can start exploring how the testes function, how different cell types within the testis interact with each other, and also try to explore whether sperm can be generated in vitro,” Nitzan Gonen, co-senior study author and a researcher in biomedicine at Bar-Ilan University in Israel, told Live Science in an email.  

Gonen and colleagues study a process called sex determination, whereby either male or female reproductive organs — the testicles and ovaries, respectively — form during embryonic development. The researchers were inspired to create the new testicle organoids after realizing there was a lack of lab models that closely resembled these organs in the human body. 

In the new study, the team extracted immature testicle cells from newborn mice and, with the help of growth-stimulating signaling proteins, drove them to form organoids. The organoid cells organized themselves in a similar way to what is seen in a normal mouse testicle. 

The team was also able to grow testicle organoids from mouse testicle cells drawn from developing embryos. Many diseases that are tied to testicle development and dysfunction occur during embryonic development, so being able to model this stage of testicle growth may be particularly important, the team wrote in the paper. 

The newly made testicle organoids didn’t produce sperm. However, there were early signs that the cells might be able to take part in meiosis, a type of cell division that is used to produce various sex cells, including sperm. Going forward, the team wants to explore whether the organoids can be made to make sperm and hormones. 

They also aspire to grow testicle organoids from human cells, and they already have one specific use in mind. Male children with cancer who are undergoing chemotherapy often lose the stem cells that will go on to form sperm after puberty begins and can, therefore, become infertile, Gonen said. The hope is that, eventually, testicle organoids could be grown from a child’s stem cells before cancer treatment begins and be used to produce fertile sperm, she said. These sperm could then be available for future fertility treatments, such as in vitro fertilization (IVF.)

Everyday Shrinkage: 5 Ways Your Testicles Are Getting Smaller And How To Prevent It

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Tiny Men
The testicles are two of men’s most sensitive, and prized, organs. Finding out that one of them is shrinking can be scary, especially when we have no idea what’s causing it.

Testicles: they don’t call them a man’s jewels for no reason. After all, they’re the source of all our manliness, producing testosterone daily, which gives us muscle definition, the hair on our faces, and the ability to perform sexually. This should explain, then, why we prize them so much, and why it hits so close to home when people like Tom Green and Lance Armstrong are diagnosed with testicular cancer — both of them got a testicle removed, and Green even had his operation televised.

There’s another condition that’s particularly scary for men: testicular atrophy, colloquially known as shrinking balls. Finding out your balls are shrinking is especially scary because you probably won’t feel anything resembling a tumor underneath, however, you’ll sure as hell be wondering what’s causing it and if you’re in danger of anything. If you ever find yourself going from walnuts to grapes down there, it could be because of one of these five reasons.

No Sleep for Shrinking Balls

In case you haven’t heard, sleep is extremely important to our overall health. Not only does it restore physical energy but it also restores our capacity for attention and memory, and boosts metabolism and heart health. Even better, it puts us in good moods.

Some research, however, suggests that losing sleep can shrink the balls. In a study from last year, researchers at the University of Southern Denmark surveyed nearly 1,000 young men about their sleep schedules, interruptions in sleep, and other habits. They also took blood samples and measured sperm counts, and found that men who had problems sleeping — insomnia, going to sleep late, or inconsistent sleep — had a 29 percent drop in sperm count. What’s more, their sperm were 1.6 percent more likely to be deformed, and their testicles had shrunk.

The researchers also noted that people who sleep late are more likely to lead unhealthier lifestyles, which could include smoking and drinking, but even then, it’s a good reason to get more sleep.

What’s That About Alcohol?

We all love our drinks in one way or another, whether they’re glammed up with fruity flavors or served neat. Alcohol has been found to benefit our health in many ways; red wine’s resveratrol is a relatively powerful antioxidant, and a drink or two can boost our creativity. But just like most things, drink too much, and you’re more likely to harm your body than help it.

Such is the case with alcohol and testicular size. In a study published this September, researchers found through both in vivo and in vitro studies on rats that alcohol caused changes to Leydig cell shape and function. These cells are located adjacent to the testicles’ seminiferous tubules, which are where sperm cells are produced. In turn, the tubules shrunk, and subsequent processes involving the way alcohol alters testicular energy metabolism and sperm cell mitochondria led to cell death. Together, these processes led to testicular shrinkage in the rats, and the researchers believe the same may be true for humans.

The good news, however, and it’s rather huge: All you have to do is quit drinking, and your testicles will likely bounce back to the size they were before.

Aluminum, Who Knew?

Okay so, most of us love to eat. And what keeps our food warm when we don’t have an actual heat source? That’s right, aluminum foil. Depending on the types of food you’re eating, the metal could be leaching in, and you’re eating it. But aluminum is found in other things too, such as tobacco, alcohol (here we go again), and even in the air.

Exposure to too much aluminum may cause a low sperm count and infertility, and a side effect of smaller testicles. In a study from last month, researchers examined 62 sperm samples and measured aluminum content, finding average of 339 parts per billion (high), with some men even having aluminum has high as 500 parts per billion. Those with the higher levels of aluminum were more likely to have low sperm counts and were therefore less fertile. Such exposure may lead to oxidative stress in the testicles, causing cells to die, and the testicles to shrink.

Limiting aluminum exposure by choosing chemical-free cleaning and personal care products may help, as well as using BPA-free plastic or glass bottles for drinking, rather than plain plastic.

Getting Kicked One Too Many Times, As If You Didn’t Suspect It Already

Our testicles have perhaps the most pain receptors concentrated in any one area of our bodies. We need them because they are the key to our reproductive success, even as they hang outside our bodies, vulnerable to attack. Getting kicked in the balls is enough to knock even the strongest man to his knees, as the pain receptors send signals through nerves that extend to the ears, stomach, and groin.

Thankfully, many men’s testicles don’t experience such trauma daily — except for those intoskateboarding. For these certain groups, or those who experience one serious hit, the balls may indeed shrink. A study from 1999 (kind of outdated, yeah, but still relevant) found that 50 percent of men who experienced “blunt scrotal trauma” saw a reduction in the volume of the injured testicle.

Thankfully, getting hit in this area is relatively rare. But if you want to be extra safe, you can get yourself a cup.

Smoke Your Balls Away… with Marijuana?

Data has been conflicting for years on many of the long-term effects of marijuana. Studies have suggested that long-term use affects the brain’s reward system, causes brain damage, and lowers kids’ school grades. But for each study that finds a problem with it, there’s another one that puts the concern back at square one.

Testicular atrophy is one such issue, although many of the studies suggesting it does cause shrinkage are relatively outdated — from the 1980s. Nevertheless, the majority of it suggests that smoking weed lowers testosterone levels, either directly or through precursor hormones; or causes testicular atrophy in monkeys and dogs. A study from 2012 revives this idea, and finds some evidence in men living in the Niger delta area of Nigeria. In that study, 75 men who smoked marijuana were also likely to have shrunken testicles, infertility, and even male breasts.

The takeaway from all of this is that it’s really just too inconclusive. Each one of the 1980s studies found that while it may have altered certain factors that could lead to atrophy, the effects weren’t long lasting. Within 24 hours to three days, testicles began to grow back to normal size. So, if you’re really worried about whether your marijuana use is causing your balls to shrink, it’s probably best to stop. But it seems that continuing might only have temporary effects, if any at all.

All of this is surely informative, and may help at hinting what’s causing your testicles to shrink. But if you suspect you have testicular atrophy, the best thing you can do is to consult a doctor. We mean it.

How do testicles know to make sperm .

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Whenever a man ejaculates millions of sperm are produced, yet the average pair of testicles produces billions of sperm in a lifetime. So, why aren’t all of these possible sperm cells created at once?

Testicles have a built in safety device that stops their owners from becoming infertile

Sperm cells come from stem cells deep inside the testicles. When these stem cells divide, they can become another pair of stem cells that stay inside the testicles, or they can start to become sperm cells. In order for men to remain fertile, their testicles need to keep these two options well balanced. If too many cells change, the reserve of stem cells could run out so that no new sperm can be made. If too few cells change, the sperm count would drop because the testicles are filled with stem cells. Either scenario would result in infertility.

One “switch” keeps the testicles from making all the sperm cells at once

A new study by Kanako Ikami et al at the National institute for Basic Biology in Japan states that a single difference inside the cells determines whether or not the stem cells go on to become sperm cells. Ikami conducted a study with mice, and she found that genes the cells were using consist of two specific groups. One group makes a protein that can dock with retinoic acid, the other group cannot not.

When it is time to make new sperm, a pulse of retinoid acid is released into the testes. All cells receive this pulse, but not all cells transform to sperm cells. Ikami found that the cells that could bind with the acid became sperm cells, the cells that remained blind to the pulse continued making stem cells. When Ikami forced the “blind” cells to make the protein necessary to bind with the acid, and then introduced them to the retinoic acid, they started to become sperm cells.

All of the cells inside the testicles are capable of making sperm. but one “switch” prevents them from doing it all in one go.