Posts Tagged ‘fertility preservation’

Your Oldest Treasure

Sunday, July 18th, 2010
And you thought this was old...

And you thought this was old...

What do you own that is 600 million years old? Your old suit? That little league baseball glove? Your cologne? In fact, every man possesses something that old, and believe it or not, it’s a gene. Not the clothing kind, but the kind you keep in your genome, in your chromosomes. We’ve talked about the Y chromosome in this space but lets take a moment to focus on a single tiny gene.

Tucked away in every cell of your body is a gene called Boule, a piece of DNA critical for sperm production. A colleague of mine just announced that the Boule gene is present in every organism from insects like fruit flies, to sea urchins, roosters, fish and man. It is in invertebrates and vertebrates alike. That is, this tiny bit of DNA has remained essential for making sperm through 600 million years of evolution. Surely the oldest treasure you own.

But what’s really impressive about the Boule gene is that is has not changed over time. And change is the rule with every other known gene involved with reproduction in every species. In fact, evolution of reproductive traits is how a species diverges from other species. It gives each species its identity. And this change can be very rapid: in some fish, reproductive traits are observed to change in fewer than a dozen generations. So why would this one gene stay the same?

We think that the Boule gene has remained true over 600 million years because it is essential for reproduction. Boule is a “quality control” gene that ensures all goes well as sperm are made. Just as you would want your new car to be well inspected so it is safe to drive when you buy it, you want your sperm to be reproductively fit. In fact, if the Boule gene is removed, sperm production stops entirely. Not a single sperm is made in its absence. Now that’s control.

What’s also impressive about the Boule gene is that since it is linked to sperm production, it means that sperm are very, very ancient cells. Seems that nature sticks with what is tried and true and feels no need to experiment with magic potions or fairy dust to get the job done. Reminds me of what Einstein once said while reflecting on relativity and physics: “God does not play dice.” When it comes to reproduction, the Boule gene phenomenon suggests that he may take even fewer chances.

Metabolomics: The Picture of Fatherhood

Sunday, February 7th, 2010
Cellular metabolites: woven together like a rug

Cellular metabolites: woven together like a rug

Call me a nerd, but I have to admit that I am pretty excited about metabolomic technology. Uh, what? Metabolomics is the study of the chemical fingerprints that cells leave behind. It does not look at genes, DNA, RNA or proteins, but is a peek into the products or metabolites that result from all this genetic orchestration. It is a “physiological snapshot” of a living cell.

This past week, we published a study that applies metabolomics to male infertility. If you have been reading this column, you are well aware of my interest in helping sterile men become fathers. Over the last decade, it has become clear that many men with azoospermia (no ejaculated sperm) may have small pockets of sperm in the testicle. The question is how to safely find that sperm without causing undo harm to the testicle. Current methods for evaluating whether sperm are present include somewhat invasive techniques such as testicular biopsy and microdissection and less invasive ones such as FNA Sperm Mapping that I invented 13 years ago. However, as I always say, there is always room for improvement.

Wouldn’t it be nice to find the “pockets” of sperm in the testis through a simple scan and avoid a biopsy? Maybe even a scan that involves no radiation exposure, like an MRI? Well, that is precisely what we have developed in this study.

We showed that magnetic resonance (MR) spectroscopy can measure metabolic activity in the testis. And given that most metabolic activity in the testis is concentrated on building sperm (remember, normally men produce 1200 sperm/heartbeat!), metabolic measurements in the testis generally reflect sperm production. The study showed that the metabolomic scanning is as accurate as a more invasive testis biopsy in reading several abnormal patterns of sperm production typically associated with infertility. It also showed that testes that contain sperm carry a distinct chemical “signature” that can be distinguished by MR Spectroscopy.

How does it work? Essentially, the scan looks for chemicals in the testis that are the building blocks for sperm production. The theory is if you see a pile of bricks in the yard, then there is a good chance that a house is being built. In the study, phosphocholine was observed as one of the building-block chemicals in the testis. The more there is, the more likely sperm are being made.

Not only that, MR Spectroscopy can evaluate for sperm in as many as 100-200 areas within the testis, significantly increasing the ability to sample for sperm well beyond any of the more invasive techniques commonly used today.

Are we ready to replace a testis biopsy with an MRI scan? Not yet, but give me some time to tweak the system a bit and perform clinical trials comparing it to current approaches. My motivation runs deep, as I know that men would rather have their picture taken than have a surgical procedure to understand whether they can be fathers.

The Quiet After the The Storm of Cancer

Sunday, January 17th, 2010
Throwing a wrench in the machinery of sperm production...

Throwing a wrench in the machinery of sperm production...

I have to admit, the testis “mapping” procedure that I developed some years ago has truly been a workhorse technique for my male infertility practice. And for the practices of other male reproductive specialists around the world as well. Creating fertility from sterility. I bring it up again because it is gathering more attention in the press as this week we recently published another paper that highlights its utility—this time in cancer survivors.

In a related study from 2002, we published that the majority of men who had been exposed to chemotherapy for cancerous or non-cancerous disease and who were “sterile” afterwards have sperm in the testis that can be safely used for fatherhood with assisted reproduction. Fine needle aspiration (FNA) mapping was employed in this study and its potential to help cancer survivors to conceive was convincingly demonstrated. The recent paper expands that group of men to include those who received not only chemotherapy and radiation therapy but also a relatively extreme treatment for certain cancers termed bone marrow transplantation.

Let’s back up a minute for a biology lesson. How does chemotherapy affect a man’s fertility? Well, the basis of its effectiveness in curing cancer is that chemotherapy preferentially kills rapidly dividing cells more than slowly dividing cells. In general, cancer cells divide more rapidly than do normal body cells. The term for this difference in cell susceptibility is “therapeutic index”. Unfortunately, sperm are also produced very rapidly (about 1200 sperm are made every heartbeat) and therefore sperm precursor cells are also very sensitive to the effects of chemotherapy. Think of sperm production as a rapidly turning set of gears and chemotherapy as a wrench being thrown into them. Ka-chunk! Machine comes to a loud and crashing halt. Sperm production is over, or tremendously slowed down. The same action is true for radiation therapy treatment.

Now, imagine not just one small wrench being thrown into the gears, but a huge wrench (or many wrenches) being suddenly thrown into the machine of sperm production. The result? More damage to the sperm-making machinery and a much higher chance of sterility. This is the essential difference between the patients from the 2002 paper on mapping and the most recent one. The cancer survivors in this week’s paper got blasted with the heaviest doses of chemotherapy imaginable, and topped off with a dollop of radiation therapy just to be sure. Hard to believe, but they also had usable pockets of sperm in their testicles. And normal babies as a result.

So, with techniques like FNA sperm mapping, there continues to be hope and good news about fertility after the storm of cancer treatment has passed.

Keeping the Family Jewels Shining

Saturday, January 2nd, 2010
Heirlooms for the species.

Heirlooms for the species.

As a living, breathing being on this good earth, we tend to take things for granted. The ability to have offspring can be one of them. That is, until the day that a serious medical condition like cancer rears it ugly head and puts childbearing at risk. In addition to the sterilizing effect of cancer treatments, the mad rush to treat the disease often marginalizes efforts to preserve fertility. Fire all the canons and check for collateral damage later.

Fertility preservation seeks to protect men, adolescents and children from a common, serious and impactful side effect of cancer treatment: infertility. The goal of fertility restoration is to empower patients who are cured and potentially infertile to bear children. These related fields have burgeoned recently because medical care is now shifting from curing cancer to improving the quality of life among survivors. And without a doubt, for many, fertility is a key quality of life issue at some point. Thankfully, exciting new methods of restoring fertility have already been developed and even newer technologies are under study.

Classic techniques for fertility preservation in men include gonadal shielding and sperm banking. Gonadal shielding uses lead-based devices to protect the testicles from being struck directly by sterilizing radiation treatment. Sperm banking is the process of freezing healthy sperm before cancer treatment begins for later use to conceive. But there is more. For patients who are too young to bank sperm, for those who have precious little time to bank sperm, or for those who have no ejaculated sperm to bank, testis sperm retrieval by biopsy (TESE) or needle aspiration (TESA) for banking is now possible before cancer treatment. In fact, in some cases of testis cancer, it is possible to remove only the cancerous nodule instead of the whole testis, or to freeze sperm from the testicle after it is surgically removed. These are now routine ways to preserve fertility in men.

Fertility restoration for men has also seen real advances lately. Sperm “mapping” is an innovation that I developed for men who survive cancer treatment but have no sperm in the ejaculate. It non-invasively and non-surgically deciphers whether there are small numbers of mature sperm in the testis, too few to get into the ejaculate, but usable nonetheless. In men who sustain nerve injury from cancer surgery and who are unable to ejaculate, a special medical instrument can produce an ejaculate for fertility purposes in a process termed electroejaculation. Techniques such as these are valuable tools to help men deemed “sterile” after cancer treatment to become fathers.

One of the most exciting areas of fertility restoration involves stem cell technology. Yes, the “promise” that we have all heard about stem cells curing disease will likely find its way into the fertility field as well. In pre-pubertal boys with cancer, ejaculated sperm is not present. Despite this, it may be possible to freeze the early stem cells from the testicles of boys before sterilizing treatment. After thawing, these “adult” stem cells may later be used to create sperm after further growth in a Petri dish or after transplantation back into the same individual. Also on the horizon is our ability to take skin cells from a sterile man, convert them into an embryonic-like stem cells and then “drive” these cells to become mature sperm in a dish–a true “artificial testicle.” So, with the belief that hope can cure misery, the world of science has taken fertility research from science fiction to reality. Not convinced? Stay tuned!