Risk of congenital heart disease is determined by the age of the mother, not her eggs

~ Betty ~ 3 Comments

As a woman of child-bearing age, I am acutely aware that the longer I postpone having children, the greater the risk that my future offspring may have a medical or developmental disorder. It seems like every few weeks, a new study makes it into the news cycle linking advanced maternal age to disease X or condition Y. (Men don’t get off scotch free – recent studies have linked advanced paternal age to autism.) A study published in Nature this week has shed light on maternal age-associated risk of congenital heart disease and risk-modifying factors.

Despite advances in diagnoses and treatment, congenital heart disease remains one of the leading causes of childhood illness and mortality. Roughly one in 100 children will have minor congenital heart disease whereas one in 1000 will require heart surgery. The risk factors for congenital heart disease include genetics, infections, maternal diabetes and advanced maternal age. A team of researchers led by Dr. Patrick Jay at Washington University School of Medicine asked whether the maternal age effect was based on the age of the mother’s eggs or the mother herself.

To tease apart these scenarios, the researchers carried out reciprocal ovarian transplants where the ovaries of young mice were transplanted into older mice and vice versa. Young mice were less than 100 days old whereas old mice were on average 318 days old (lab mice live on average two and a half years or roughly 850 days). They compared what proportion of the offspring of these two groups of mice had congenital heart disease by looking for ventricular septal defects (VSD). Ventricular septal defects are a common birth defect of the heart where there is a hole in the wall separating the lower chambers of the heart. The offspring of older mothers with young ovaries developed VSD significantly more frequently than the offspring of young mothers with old ovaries. This result provides compelling evidence that the risk of congenital heart disease is associated with the increased age of the mother and not of her eggs. Continue reading →

Rethinking Salmonella: from food poisoning culprit to cancer-fighting agent

~ Betty ~ 3 Comments

What would you look for in an ideal cancer treatment? You’d probably want something that would only kill cancer cells and leave healthy cells unharmed. It would also be nice if this drug could penetrate deep inside tumours, even if the tumours are dispersed across multiple sites in the body.

What if that anti-cancer treatment was a dose of Salmonella? Would you try it?

Scientists are developing ways to transform bacteria like Salmonella into lean, mean tumour-fighting machines. A new study published this week in Proceedings of the National Academy of Sciences describes a new and innovative way to turn Salmonella into highly specific vehicles that can deliver anti-cancer compounds into the heart of a tumour. Continue reading →

Wounded by love: snails struck by love darts have lower survival and reproductive rates

~ Betty ~ 4 Comments
"Shot through the heart and you're to blame, you give love a bad name" In this image of two mating snails, the snail on top shot a love dart through the head of its mating partner. (Credit: Chase and Blanchard, Proc. R. Soc. B (2006) 273, 1471–1475)
“Shot through the heart and you’re to blame, you give love a bad name” In this image of two mating snails, the snail on top shot a love dart through the head of its mating partner. (Credit: Chase and Blanchard, Proc. R. Soc. B 2006, 273:1471)

In classical mythology, Cupid carries two types of arrows: one with a sharp golden tip and one with a blunt tip made of lead. Those struck with the golden arrow are filled with uncontrollable desire while those wounded with the lead arrow are filled with revulsion. In these modern times, we humans are less likely to rely on a winged cherub carrying a quiver full of arrows to help us find love than on online dating sites and Tinder. That’s not to say that projectile weapon systems like the bow and arrow have become obsolete in affairs of the heart. Some species of land snails shoot love darts at their mating partners to increase their reproductive success.

As violent as it sounds, stabbing their mating partner with a love dart improves the likelihood that a snail will father offspring.  These sharp and pointy darts are made of a crystalline form of calcium carbonate called aragonite and coated with mucus. If the dart hits its target, chemicals in the mucus coating are released into the recipient snail’s blood stream. These chemicals serve as signals that trick the female reproductive organs to divert the shooter’s sperm away from the sperm digesting organs and into the sperm storage organs where they can fertilize eggs later. While love darts are known to carry clear benefits for the shooter, not a lot is known about how being hit by a love dart affects the recipient. For the first time, scientists have experimentally studied the costs of this violent and traumatic behaviour to the individual being stabbed. Continue reading →