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Do Microbes Influence Our Love Life?

How our microbiome develops and what role the microbes in the gut and vagina play for our health, especially during pregnancy, is my recurring theme here at FP. To read some of my previous posts on the matter, click here.

My daughter got married this last summer and it sparked a thought about a very interesting question. Could it be, that microbes also affect which people we are attracted to and which sex partners we choose? 

Can we use scent to detect a suitable partner?

The bacteria on our skin contribute to our body odor, which is an important part of how we choose a partner. For example, the bacteria transform the oil we have on our skin into a very unique blend of fatty acids and other substances that give us a distinctive scent, our very own signature. Imagine the process as a lure that the bacteria produce to gain access to another human body host to colonize. After all, sex can be quite sweaty and messy, an almost perfect set-up for bacterial transmission.

In addition to this, our immune system plays an important role in how we perceive the scent of other people. Our immune response genes become yet another personal scent signature that has been trained by bacteria from an early age. There are studies that show that we unconsciously choose a partner with immune response genes that are different from our own.

Bacteria communicate with each other through different signaling substances, some of which are the same hormones that cells in us humans produce, such as oxytocin and serotonin. They contribute to our love life by regulating our moods and are needed for our well-being and sense of closeness.

In a controlled study of 21 couples who were intensely kissed, a research group from Amsterdam showed that about 8 million bacteria were exchanged per second. One person from each couple had to drink a probiotic yogurt before kissing, and the researchers measured the probiotic bacteria in the saliva of the partner. In addition, the study showed that couples who kiss each other often have a bacterial flora in their mouths that is more similar to each other than that found in the mouth of other people.

How should we deal with the invasion of microbes in our love life?

First, don’t try to hide your own scent signature by using too much perfume or cologne. Secondly, you may not need to use such large amounts of soap as what it common nor shower too frequently (this also saves on the environment). Above all, make sure to nurture your bacterial flora on and in your body through a varied diet that contains a lot of fiber, a lifestyle of regular physical activity and some time in nature. It helps you maintain radiant skin and an irresistible scent of health and attraction. Instead of dating apps, you just need to get out in the crowd and trust your nose!

There is very little we know today about the role of bacterial flora in women’s health and the correlating potential to give birth to healthy children. But we at the Center for Translational Microbiome Research have started several studies to find out. The SweMaMi study has now received samples from 1000 mothers and children, 1000 pregnant women are already present and will send more samples to us but 500 are still missing. So I can’t help but ask, are you pregnant? and are you interested in participating? 

Ina Schuppe Koistinen is an Associate Professor at Karolinska Institutet and works at the Center for Translational Microbiome Research to study the role of bacterial flora in inflammatory bowel diseases and women’s health. In addition to her research, she is passionate about yoga and guiding people to a healthier lifestyle. She is also active as an artist with watercolor as a medium. The views in the chronicle are the writer’s own.

Watercolor: Ina Schuppe Koistinen

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Vaginal Delivery Induces “Good” Stress

A little more than a year ago, my son was born. And, just as the birth of my daughter had been, the delivery became an emergency caesarean section. Neither my first nor my second went all the way, despite hours even days of pain and contractions.

Why am I telling you this? Yes, believe it or not, but the stress induced by giving birth vaginally actually equivalates to a positive impact. At least for the child anyways.

Five years ago, my colleagues did an attention-grabbing study in which they looked epigenetically at how children are affected by vaginal birth compared to being born via caesarean section. This in light of previous studies that have shown that children born via a planned cesarean section have a higher risk of developing asthma, type 1 diabetes, obesity and gluten intolerance later in life. The reason for the connection is not fully established, but as planned caesarean deliveries have increased in many parts of the world, it is of increasing importance to look into this more closely.

In my study, my colleagues investigated epigenetic changes in stem cells from cell-sorted umbilical cord blood. Global epigenetic analysis was performed on 43 newborn infants, 18 of whom were delivered with planned caesarean section. Furthermore, DNA from twelve newborns (six planned cesarean sections) was analyzed for gene-specific epigenetic change throughout the genome.

The results show specific epigenetic differences between the groups at nearly 350 sites in the genome. The genes with different methylation patterns were involved, among other things, in processes that control the metabolism and the immune system.

The study provides support for the theory that the act of giving birth itself leaves imprints in the genome of the newborn baby’s stem cells. The discovery may be important to understand why people born with caesarean section are statistically at increased risk for immunological diseases. However, it is still unclear whether the so-called epigenetic change is temporary or persists for a long time. The biological mechanisms that predispose a fetus or newborn to diseases later in life are complex and depend on both inheritance as well as environment during the fetal stage and throughout adolescence (which I wrote about earlier).

But what could this “good” stress* be positive for?

One possible explanation is that during a vaginal delivery, the fetus is subjected to a progressively increasing and very strong stress onset, which here is positive for the child and prepares it for life outside the uterus. This stress is believed to activate the child’s defense system for adaptation to life after birth, which is absent in planned Caesarean sections where the work of labor never starts. However, it is important to remember that many immunological diseases, including those mentioned above, are a result of both inheritance and the environment, and that our epigenome is not static but is affected by our internal and external environment throughout our lives.

Finally, I sometimes can’t help but think that no matter how much advanced technology and knowledge we get, we often cannot circumvent biology. Maybe something to comfort yourself with the next time you think back on your (or your partner’s) labor. Or when you’re breathing through the pain of your upcoming labor. And to those who have had emergency C-sections: those hours of pain pre-cesarean were actually useful. So don’t despair!

(This post does not try to blame or act as a pointing stick. My view is that every woman decides over her own body and knows what it can and does best. For many, planned caesarean sections are a medical necessity. As I see it, knowledge is power to be able to make sensible decisions and change the world in a positive direction.)

* However, it should be clarified that the type of stress we are talking about here is not the same as chronic, long-term, stress. Which has on the contrary been shown to have negative health effects (which I do not go into here).

Louise Sjöholm has an education in molecular biology and a doctorate in depression genetics from Karolinska Institutet. She has been working as an epigeneticist for seven years and is researching the role of the gastrointestinal tract in autoimmune diseases, i.e., diseases in which the body’s immune system attacks its own tissue. She is also interested in understanding the epigenetics of bacteria and its connection to health and disease. The views in the chronicle are the writer’s own.

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Exercising the Patience Muscle, What it’s Like Working as a Researcher?

Time for an update on how things have gone for our SweMaMi study thus far, plus a look into what it’s like to be a researcher. As I wrote last autumn, our research group studies the relationship between pregnant women’s bacterial flora (with samples from the mouth, gut and vagina) and various pregnancy complications. We sync the data from the analyzed bacterial flora and the questionnaire about the woman’s pregnancy, lifestyle, health, eating habits, stress, bowel function and other things. In addition, we ask the parents to collect a sample from the diaper from the newborn baby and we then follow the child’s health for many years to come.

Today we have recruited about 2,300 pregnant women to the study, but fewer than 2000 have submitted samples. We had hoped to finish the recruitment now this summer, but due to the large drop-out we need to extend the recruitment time until we reach our goal of 2,500 women who have both filled in the surveys and submitted the samples to us. Then we need to wait until all SweMaMi babies are born to get the last samples before we start analyzing. You can see how this takes a lot of patience.

In the meantime, we have begun to analyze the questionnaire responses from the first 2000 pregnant women in the study. We are pleased to see that we have received data from almost all of Sweden, about 60% of the studies participants come from areas outside of Stockholm. In addition, the age distribution seems to be representative of pregnant women in Sweden as well. When it comes to education and work, we mainly reach women with college education and full-time jobs, which unfortunately does not represent all pregnant women in Sweden. This will limit our ability to generalize our findings to the entire population.

So far, about 650 babies have been born by mothers who are part of the study, and for the first 444 participants, we have evaluated the questionnaire responses regarding eating habits as well as the reports of depression after childbirth. There seems to be a link between unhealthy eating habits and the onset of depression, especially when it comes to high consumption of sweetened beverages and low consumption of vegetables. Perhaps not quite unexpected, but an important finding that we will analyze further considering that the connection between the intestinal flora and our mental health is a hot research area. Studies in mice show that intestinal bacteria can affect brain development and animal behavior. But when it comes to people, there are no studies that show the connection between the bacterial flora and our mind. Above all, it is uncertain what is cause and what is effect. The connection may be due to several things, such as the fact that it is common to eat sweets as a form of self comforting, but it could also be that the diet affects mental health via a change in the bacteria. We do not yet know how the bacteria in the mouth, intestine and vagina interact with each other in our bodies, hence why our study is so important.

Our research team tries to collect all the knowledge available on pregnancy and bacterial flora, but at present it cannot make any recommendations on specific pre- or probiotics that could prevent miscarriage, premature birth or depression in expectant mothers. Sometimes it may feel a little frustrating, but the more understanding we get for the complexity of the interaction between our bodies and the trillions of microbes that live in and on us, the harder it will be to make cross-proof statements about which we should add. Unfortunately, many unscientific advice is being disseminated by self-proclaimed media experts. Science as of today can only recommend a Mediterranean style diet and a lifestyle with a lot of physical activity to avoid the bacterial flora adversely affecting pregnancy and fetal development.

So more patience is required, but if every women who is pregnant (earlier than week 19) and finds herself residing in Sweden could imagine participating in the SweMaMi study, then, we can together come a bit further in our understandings. Help us spread the information about the study and base the recommendations given to pregnant women on scientific facts.

Subscribe to our study at www.swemami.se. You are also welcome to follow us on Facebook and Instagram: SweMaMi.

Ina Schuppe Koistinen is an Associate Professor at Karolinska Institutet and works at the Center for Translational Microbiome Research to study the role of bacterial flora in inflammatory bowel diseases and women’s health. In addition to her research, she is passionate about yoga and guiding people to a healthier lifestyle. She is also active as an artist with watercolor as a medium. The views in the chronicle are the writer’s own.

Watercolor: Ina Schuppe Koistinen

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Twins – An Important Epigenetic Tool

An important part of my work is to carefully plan my studies so that we actually measure what we intend on measuring and nothing else. Maybe this sounds straightforward but it’s not quite that easy.

As an epigeneticist, I study the impact of the environment on the genome (read more here). What makes it all difficult is that our epigenome is not static, but constantly exposed to changes from our environment. For example, if we discover an epigenetic difference between sick and healthy people, we cannot say whether the difference seen  is the cause of the disease or a consequence of it. In most cases we are studying people who are already sick. And, to make things all the more complicated, most diseases are the result of a combination of heritage and the environment.

So how do we get around around this? There are a few different ways to design a study to filter out the noise of unwanted signals, and clarify what is cause and effect. One way to sort out the noise from our genes and just study the environmental impact is to use twins. Identical twins have the same genome and to some extent a common environment, however, the older they get the more separated their living environment and habits tend to become. And this is what we benefit from when studying twins where only one twin has suffered from a particular disease.

In one of our studies, we studied epigenetic changes and rheumatic disease with the help of identical twins from the Swedish Twin Registry. And to find out more about the onset of the disease, and not just the effect, we also studied “healthy” twins who have not yet been affected by rheumatism, but who are likely to develop the disease as they have a certain type of antibody in their blood that is associated with rheumatism (antibodies against ACPA).

With this approach, we were able to identify methylation differences that were not dependent on the interference of the genes. But why do you want to do this? Well, in the vast majority of studies that investigate rheumatism, a certain group of genes pop up, the so-called HLA genes. These genes encode proteins that help our immune system talk about what is body-like or body-foreign.

The HLA genes are involved in one way or another in rheumatism, and also in many other autoimmune diseases. But, with the help of identical twins, we could identify other genes involved in addition to the HLA genes. The PCDHB14 gene was found to be differently methylated in both the “healthy” twins with ACPA antibodies in their blood and the diseased twins, suggesting that this gene is involved in the actual development of the disease.

PCDHB14 belongs to a large complex gene family that is mainly expressed in the brain and which has been reported to be involved, just like the HLA genes, in sensing what is own and body foreign. Super interesting! In the mentioned study, we could not point out which environmental risk factor or factors could possibly be behind the development of the disease, but we gained knowledge about which biological systems could be involved in rheumatism. One puzzle piece at a time!

In another study, we focused instead on one of the most common risk factors for many autoimmune diseases, namely smoking. We wanted to investigate how smoking affected MS patients and then looked at smokers, former smokers and MS patients who had never smoked. But I’ll tell you more about this in my next post here at Food Pharmacy.

Louise Sjöholm has a education in molecular biology and a doctorate in depression genetics from Karolinska Institutet. She has been working as an epigeneticist for seven years and is researching the role of the gastrointestinal tract in autoimmune diseases, i.e., diseases in which the body’s immune system attacks its own tissue. She is also interested in understanding the epigenetics of bacteria and its connection to health and disease. The views in the chronicle are the writer’s own.

Photo by Sharon McCutcheon on Unsplash

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