The foundations of eczema can start to be established in the uterus

Stress during pregnancy, perhaps towards the brand of 6 to 8 months, perhaps in particular in certain immune cells in the skin of a fetus to react excessively, leading to eczema.

Immune cells called mastocytes in the skin release histamine and other chemicals that trigger redness, swelling and itching during allergic reactions. Eczema is not a type of allergy, but these same chemicals can help power the inflammatory thrusts that it induces in response to irritating, rough or humid substances, such as soap, washing of detergents and layers.

A series of mice experiences has now shown that mastocytes become hyperreactive when a fetus is exposed to stress hormones in the uterus.

“Something our work brings out is that the emotional experiences of pregnant women can indeed have an impact on the health of their children,” explains Nicolas Gaudenzio to Toulouse Institute for Infectious and Inflammatory Diseases in France. “Making feel guilty of mothers is absolutely not the purpose of this research. Maybe it’s more a message for women’s partners and their support systems. ”

Previous research has suggested that there is a link between stress during pregnancy and eczema in newborns. To understand the mechanisms behind it, Gaudenzio and his colleagues have carried out experiments on dozens of pregnant mice.

Some were put under stress while being placed in narrow tubes with lively lights that shone on it for half an hour, three times a day for five days. The researchers specifically targeted the end of the second quarter of the second and at the beginning of the third quarter, a critical window for the development of immune and nervous systems. They found that mouse stress hormone levels increased both in the blood circulation and the amniotic fluid during this period.

After the birth of the puppies, the researchers imitated the wearing of layers by placing pads soaked in a saline solution on their backs or gently rubbing the adhesive ribbon behind their knees and in the elbows of their elbows – typical eczema hot spots.

They found that almost all the offspring of stressed mothers developed rashes of the eczema type which were red, itching or frozen on these sites, while those who were born to control mothers – who were free to walk in a cage during pregnancy – sometimes showed a slight irritation, but never full lesions.

The sequencing of RNA of sensory neurons connecting the skin to the spinal cord revealed that nearly 300 genes were expressed differently in the offspring of stressed mice, many of which are linked to pain, touch and itching, suggesting increased sensitivity of the skin. The puppies born of stressed mothers also reacted much more strongly in soft contact, as being brushed with fine nylon filaments.

The sequencing of immune cells in the skin of puppies showed 500 genes expressed differently in mastocytes. Under the microscope, they seemed to prepare to release histamine. “They were already active at rest, in a neutral environment, which means that the skin is predisposed to develop inflammation,” explains Gaudenzio.

The researchers repeated their experiences in pregnant mice treated with drugs that prevent them from creating corticosterone, a hormone that plays an important role in the response to stress in rodents, and these puppies did not have eczema. They also gave additional corticosterone to pregnant mice that were not in stressful situations – their puppies have developed an eczema.

The researchers are then genetically modified to completely lack mastocytes. These animals did not develop eczema, even when their mothers had been stressed.

“This is a fairly in -depth and very interesting study,” explains Thomas Plum, who specializes in cell immunology at the German cancer research center in Heidelberg. “He underlines this new vision in the field which, in terms of tissues, the interactions between immune cells, structural cells and the nervous system are everywhere and play really important roles.”

Even so, it is important to keep in mind that the experiments have been carried out on mice. “It’s intriguing, but it’s just the first foot of the door,” explains Plum.