Your mother *is* always with you

Mother and child, microchimeras

When you’re in utero, you’re protected from the outside world, connected to it only via the placenta, which is supposed to keep you and your mother separated. Separation is generally a good thing because you are foreign to your mother, and she is foreign to you. In spite of the generally good defenses, however, a little bit of you and a little bit of her cross the barrier. Scientists have recently found that when that happens, you often end up toting a bit of mom around for decades, maybe for life.

The presence of cells from someone else in another individual is called microchimerism. A chimera in mythology was a beast consisting of the parts of many animals, including lion, goat, and snake. In genetics, a chimera carries the genes of some other individual along with its own, perhaps even the genes of another species. In microchimerism, we carry a few cells from someone else around with us. Most women who have been pregnant have not only their own cells but some cells from their offspring, as well. I’m probably carrying around cells from each of my children.

Risks and benefits of sharing

Microchimerism can be useful but also carries risks. Researchers have identified maternal cells in the hearts of infants who died from infantile lupus and determined that the babies had died from heart block, partially from these maternal cells that had differentiated into excess heart muscle. On the other hand, in children with type 1 diabetes, maternal cells found in the pancreatic islets appear to be responding to damage and working to fix it.

The same good/bad outcomes exist for mothers who carry cells from their children. There has long been an association between past pregnancy and a reduced risk of breast cancer, but why has been unclear. Researchers studying microchimerism in women who had been pregnant found that those without breast cancer had fetal microchimerism at a rate three times that of women who with the cancer.

Microchimerism and autoimmunity

Autoimmune diseases develop when the body attacks itself, and several researchers have turned to microchimerism as one mechanism for this process. One fact that led them to investigate fetal microchimerism is the heavily female bias in autoimmune illness, suggesting a female-based event, like pregnancy. On the one hand, pregnancy appears to reduce the effects of rheumatoid arthritis, an autoimmune disorder affecting the joints and connective tissues. On the other hand, women who have been pregnant are more likely to develop an autoimmune disorder of the skin and organs called scleroderma (“hard skin”) that involves excess collagen deposition. There is also a suspected association between microchimerism and pre-eclampsia, a condition in pregnancy that can lead to dangerously high blood pressure and other complications that threaten the lives of mother and baby.

Human leukocyte antigen (HLA)

The autoimmune response may be based on a similarity between mother and child of HLA, immune-related proteins encoded on chromosome 6. This similarity may play a role in the immune imbalances that lead to autoimmune diseases; possibly because the HLAs of the mother and child are so similar, the body clicks out of balance with a possible HLA excess. If they were more different, the mother’s immune system might simply attack and destroy fetal HLAs, but with the strong similarity, fetal HLAs may be like an unexpected guest that behaves like one of the family.

Understanding the links between microchimerism and disease is the initial step in exploiting that knowledge for therapies or preventative approaches. Researchers have already used this information to predict the development of a complication in stem cell transplant called “graft-versus-host disease” (GVH). In stem cell transplants, female donors with previous pregnancies are more associated with development of GVH because they are microchimeric. Researchers have exploited this fact to try to predict whether or not there will be an early rejection of a transplant in kidney and pancreas organ transplants.

(Photo courtesy of Wikimedia Commons and photographer Ferdinand Reus).

Just eat the broccoli, preferably steamed

A presidential/vegetable debacle

When the first President Bush indicated a distaste for broccoli during his presidency, he set off a firestorm of vegetable-based controversy. Broccoli haters sympathized, but nutritionists were horrified. Turns out, the data are all on the side of the nutritionists.

Research has shown that people who eat cruciferous vegetables—for example, broccoli, cabbage, or cauliflower—have lower rates of cancer. Armed with this information, researchers around the country have sought the cancer-fighting ingredient in broccoli and tried different ways to maximize the benefits we can get from it.

Yes, it’s got healthy stuff in it

They pinpointed the compound of interest in 1992. It is sulforaphane, a phytochemical in a group called the isothiocyanates. These compounds are known to induce apoptosis, or programmed cell death, of cancer cells. Epidemiologists—people who trace and track diseases and their causes—have found lower rates of prostate cancer in men who eat diets high in isothiocyanates. Scientists found that the way we release these cancer-fighting compounds from our veggies is to cut or chew them.

Sulforaphane, one of the most powerful anticarcinogens—anti-cancer compounds—in our food, works through the liver. Our livers are responsible for detoxifying our bodies, which happens in phases. In some cases, liver enzymes can actually turn compounds into carcinogens. But our phase II liver enzymes break down toxins before they can damage our DNA, the molecule that houses our genetic code. Sulforaphane boosts these phase II enzymes, thus wielding its anti-cancer power.

Broccoli pill–or just broccoli?

When the world found out broccoli’s secrets, there was a craze for broccoli-derived supplements that contained sulforaphane. Broccoli-based pills, powders, and teas hit the shelves, and people everywhere crunched into broccoli, possibly wincing like our former president might have as they chewed it up and forced it down. But what they may not have realized is that mature broccoli also has some compounds help liver enzymes that turn compounds into carcinogens. The goal was to find a way to deliver sulforaphane without delivering too much of these less-benign accompaniments, or too much sulforaphane, which can be toxic in large amounts.

One approach was to synthesize a sulforaphane that retained its anti-cancer powers, but was not as toxic in high doses. This compound is called oxomate, and it has been successful in the lab in reducing breast tumors in rats. Another approach was to try to find a broccoli growth stage that made sulforaphane in reasonable amounts, but that did not produce the compounds that elicited the liver’s carcinogen-producing enzymes. Scientists following that line of research discovered that broccoli sprouts, tiny alfalfa-like sprouts grown from broccoli seeds, contain abundant and safe levels of sulforaphane, but do not synthesize the unwelcome compounds that boost carcinogenesis.

When proteins attack

But one thing that food scientists had found was that even when broccoli was consumed, its sulforaphane could be immediately disabled by broccoli protein called the epithiospecifier protein. Sulforaphane in the plant is attached to a sugar via a sulfur bond. When we cut or chew the broccoli, we can activate the enzyme that breaks the sulforaphane off of the sugar. But then there’s that sulfur flapping in the breeze, and the epithiospecifier comes along, yanks off the sulfur, and inactivates the sulforphane. Food researchers have found that cooking broccoli for 10 minutes at 140 degrees Fahrenheit kills off the epithiospecifier protein, leaving behind intact sulforaphane and the enzyme that releases it from the sugar to do its good work in our bodies.

So if you’ve been choking down overcooked broccoli all in the name of health, you may have been reaping the benefits of fiber or other broccoli-derived nutrients, but you weren’t getting much sulforaphane out of it. Your best bet, according to researchers, is to steam fresh broccoli for about three or four minutes and eat it, cheese sauce optional.

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