Karolinska Institutet

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The Link Between Gut Bacteria and Cancer Treatment

Lars Engstrand is a physician and professor at Karolinska Institutet in Stockholm, and the director of Centre for Translational Microbiome Research (CTMR). For more than 30 years, he has been studying the microorganisms in the gastrointestinal tract, and he was one of the first to study the intestinal flora with new and powerful DNA techniques. In his spare time, Lars enjoys singing and is a member of the male choir Orphei Drängar.

Why do people with cancer respond differently to cancer treatment? In recent years, outcomes for cancer patients have improved thanks to so called immunotherapy, a type of treatment that engages the immune system to attack tumors. Immunotherapy has proven to be effective, and some say it is set to revolutionize the treatment of cancer. However, some patients respond better than others, and in around two-thirds of people, cancers are resistant to this type of treatment. For a while now, researchers have been trying to figure out why. Immunotherapies unleash the body’s immune system to fight cancer cells – why patients respond differently to this treatment remains a mystery.

New research is showing a link between a person’s gut microbiome and the effectiveness of cancer immunotherapy. It seems like the bacteria found in a patient’s digestive tract can in fact affect the outcome of the treatment. Understanding which patients will benefit from immunotherapy is a big challenge, and this research is a step towards identifying these people. Certain bacteria seem to boost the effectiveness of the treatment and, if we alter the composition of the microbiome, we may be able to influence the outcome of the treatment and help the body’s immune system fight the disease.

Clinical studies of how to improve responses to immunotherapy are underway. In some studies, cancer patients are given supplements of cultivated bacteria from people who have previously responded well to immunotherapy. In others, researchers are exploring the possibility of altering patients’ gut bacteria through microbiota transplants from people with strong responses to these therapies. All in the hopes of helping the immune system to recognize and better attack the cancer cells.

These are very early-stage studies. How some bacteria are able to trigger our immune system to fight the cancer is still unknown, and researchers from both America and Europe are looking for answers. Changing your eating habits is another way to affect the microbiome, and thereby influence the effectiveness of immunotherapy. But more research has to be done. However, a widely accepted hypothesis is that a good gut microbiome can join the fight against cancer.

Our group of scientists is exploring the gut microbiome in the healthy population, in hopes of understanding what makes up a healthy microbiome and how it affects the human body. In the future, this will help us evaluate the role of probiotic supplements in the treatment or prevention of various diseases.

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Karolinska Institutet

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Microbiome-Friendly Food Will Keep Your Vagina In A Good Mood

Ina Schuppe Koistinen is an Associate Professor and Alliance Director at the Centre for Translational Microbiome Research (CTMR), at Karolinska Institutet in Stockholm. Through her research, she is exploring the human microbiome and its connection to inflammatory bowel diseases and women’s health. She loves yoga and is passionate about helping others make healthy lifestyle choices. She is also an artist, specializing in watercolor painting.

Bacteria and other microorganisms are found everywhere within and on the surface of our bodies, such as in our intestines, on our skin and in our mouths. Most of them are good for our health. Earlier scientists thought that babies are born sterile but that may not be true. At delivery, the mover passes microbes onto the baby as the newborn passes through the birth canal. Babies born by C-section pick up microbes from the mother’s skin and the hospital environment. There are also bacteria in breast milk that will influence the newborn baby’s health and gut flora. Another type of bacteria that have significant implications for a women’s overall health is the vaginal flora. Despite its importance, surprisingly little is known about the composition of a healthy vaginal flora. Our researcher group is trying to get to the bottom of this.

Most women have a large amount of Lactobacillus bacteria in their vaginal tract. They help maintain a low vaginal pH, which creates an unfriendly environment for “bad” bacteria like Chlamydia, Gonorrhea and Gardnerella (that is associated with a smelly vaginal discharge and Bacterial Vaginosis). The fungus Candida can survive in a wide range of pH levels, but in a more alkaline environment that lacks Lactobacilli, Candida is more likely to overgrow and cause symptoms.

A healthy vaginal flora is made up of many different types of bacteria, the predominant bacteria being Lactobacillus. They are superheroes and play a key role in defending against infection. But how can you encourage lactobacilli to thrive in your vaginal microbiome? The answer is simple: lead a healthy lifestyle, eat a varied diet, exercise and practice safe sex. Another good tip is to combat vaginal dryness by avoiding soap that can affect the pH levels in the vagina and cause irritation.

Studies suggest that probiotic Lactobacillus has a beneficial effect on the vaginal microbiome. It’s a fascinating thought that these little bugs travel all the way from the intestines to the vaginal tract. Isn’t it incredible how these things work?

To define the composition of the vaginal microbiome in adult women, our group of scientists has initiated a number of large clinical studies, in collaboration with Uppsala University Hospital and Professor Matts Olovsson. The study is called VaMiGyn (Vaginal microbiome and gynecological health) and we investigate the relationship between changes in the vaginal flora and the development of cervical cancer.

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Karolinska Institutet

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Epigenetics – the Link Between Genes and Environmental Factors?

A couple of weeks ago, we talked to Louise Sjöholm, Assistant Professor at Karolinska Institutet in Stockholm from the department of Clinical Neuroscience. She investigates the role of the gastrointestinal ecosystem in autoimmune diseases, and is a true expert in the field of epigenetic research. We asked her to tell us about epigenetics.

The term epigenetics, like so many other terms, was derived from a Greek word. The Greek prefix epi– implies features that are “on top of” or “in addition to”, in this case, genetics. However, to fully understand the concept of epigenetics, we need more information. For example, what is genetics? Genetics is the study of heredity in living organisms and explains why living things pass on characteristics (or traits), like height or hair color. Genetics also explains why some diseases, like multiple sclerosis (MS), breast cancer and type 1 diabetes, are passed down from parents to child. We are all born with a set of inherited genes.

Our genetic code or DNA contains a lot of information. The DNA is like an encyclopedia and the different books are our chromosomes. A mutation, a change in DNA, could be viewed as a spelling mistake. All cells have access to the complete encyclopedia, but they are only interested in a couple of pages here and there. This is where epigenetics comes in. It guides the cell and tells it where to look for relevant information: in which book, and more specifically, in which chapter and on what page. The cell is guided by so called epigenetic marks. They are like underlines, crossed out text and bookmarks, telling the cell exactly where to read. Thus, epigenetics influences all physiological processes, from when the egg is fertilized to the day we die. But what happens when things go wrong? Unfortunately, if these physiological, epigenetic, processes are disturbed it can also lead to disease.

What about the influence from environmental factors on these epigenetic marks?
Different types of food have potential to influence these epigenetic marks, or bookmarks in the encyclopedia. One of the most studied epigenetic marks is methylcytosine (a methyl group is added to the base cytosine, C). DNA methylation, the process of adding a methyl group to the DNA, is essential for normal development, and one of the nutrients needed for proper methylation is folate. High folate foods include spinach and other leafy greens. Folate can also be produced by intestinal bacteria. Other environmental factors that can influence the epigenetic process such as methylation, besides from what we eat, are long-term stress, viral infections and smoking. When these essential epigenetic processes are disturbed, we are at an increased risk of developing diseases. Also, if you in addition were born with a genetic variant predisposing you to a certain disease, epigenetics can have a negative synergistic effect.

You are born with a set of genes, but the expression of those genes is not set in stone. Epigenetics is the link between genetics and environmental factors.

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