The gut microbiome may be involved in Kawasaki Syndrome

Clinical manifestations and time course of Kawasaki disease

Kawasaki disease occurs in young children, and is characterized by long-lasting fever, coughing, diarrhea, along with other symptoms. What specifically causes this disease is unknown, but scientists guess it may be influenced genetically or by intestinal microbiota. Japan seems to have an unusually high rate of occurrence of KD. Researchers in Tokyo performed a longitudinal study of the intestinal microbiomes of KD patients, in order to look for any patterns that could suggest a relationship between intestinal microbiota and Kawasaki disease. The results have been published by Frontiers in Microbiology.

Fecal samples were collected from 28 Japanese children, ages ranging from 3 months to 9 years 6 months. Patients were both male (15) and female (13).  Fecal samples were collected twice from each child, for a total of 56 samples. The first (acute phase) sample was taken at the time of hospital admission, while the second (non-acute phase) was collected 4-6 months after the onset of Kawasaki disease. DNA was extracted from the fecal samples and sequenced to determine the bacterial composition of the intestines.

Roseburia species were found to be relatively abundant during the non-acute phase (4-6 months after disease onset). Species of Streptococcus were found mainly during the acute phase, such as S. pneumonia, orlais, pseudopneumoniae, mitis, gordonii, and sanguinis. This means there is a potential that these species of Streptococcus could be related to KD. To further determine if the Streptococcus species were related to KD, the researchers compared the species’ genomes to recent research in which they are involved, and found that Streptococcus could be a biomarker or pathogen for diseases with unknown causes, such as Kawasaki disease. While this is still a hypothesis and nothing is proven to be 100% true yet, it is definitely a topic that will be researched extensively in the nearby future. It may hold the key for understanding many other diseases whose causes are a mystery.   

Specific mushroom alters microbiome of mice to reduce obesity

Natural medicinal products are used around the world and prominently in Eastern civilizations. One such product, the Ganoderma lucidum mushroom has been used for centuries to promote better health. Scientific research has shown that polysaccharides (complex sugars) isolated from the fungus prevent fat cell formation in diabetic mice, and other isolates promote antidiabetic activity. Scientists in Taiwan were curious as to whether G. lucidum had any effect on body weight and obesity-related disorders such as chronic low-grade inflammation which leads to insulin resistance, type 2 diabetes, and fatty liver disease, and they published their results in Nature Communications.

The researchers tested whether water extract of G. lucidum mycelium (WEGL) can decrease obesity in high fat diet-fed mice (HFD).  A group of mice was fed a control chow diet, while another group was fed a high fat diet for 8 weeks. The chow and HFD-fed mice were treated daily with either water or WEGL at 2, 4, or 8% for two months.

The obese-human microbiome is often characterized by an increased Firmicutes- to-Bacteroidetes ratio. The researchers examined the gut microbiome of the mice and found that treatment of HFD-fed mice with 4% and 8% WEGL reduced the bacterial ratio to resemble one similar to that of chow-fed mice. In another test, 8% WEGL HFD-fed mice had an increased variety of bacterial species that negatively correlate with obesity, such as Parabacteroides goldsteinii, Anaerotruncus colihominis, Roseburia hominis, and more.  

WEGL fecal transplants were performed on some mice as well, which determined that it was indeed the altered gut microbiota of WEGL HFD-fed mice that is improved as the obese mice receiving the fecal transplant had reduced weight and a reduced Firmicutes-to-Bacteroidetes ratio. Overall, it appears that WEGL affects the gut microbiome of HFD-fed mice in a way that alters it to more closely resemble the microbiome of chow-fed mice. It was discovered that the high molecular weight polysaccharide fraction of WEGL may be responsible for its beneficial effects. While this is an exciting finding, this study was conducted in mice and it will be important to better understand the impacts this has on humans before people are out buying these mushrooms with the hope that it will lead to decreased obesity. 

Schisandra chinensis fruit modulates microbiome in obese women

Flower from Schisandra chinensis fruit plant

A search for the blog posts on our site about obesity will result in a list of posts discussing correlations between obesity and bacteria in the gut. People have hypothesized that by modulating the microbiome, you may be able to alter obesity levels in humans. Many studies have looked at how probiotics and prebiotics can modulate bacterial structure to control obesity and metabolic diseases, however little has been done to look at how herbs and fruits could modulate bacterial composition.

A recent study from Korea looked at Schisandra chinensis fruit (SCF), a fruit found most commonly in northern China, that has a long history of being used in East Asian culture as a therapeutic for conditions such as diabetes, obesity, cough, and other conditions.  Previous studies of SCF in mice have shown that it modulates the microbiome, however no human trials had been previously conducted. To analyze this in humans, a clinical trial was conducted in Korea to look at the impact that SCF had on gut bacteria, body composition, and blood chemistry.

At the Dongguk University Ilsan Hospital in Korea, scientists recruited women who were obese (BMI over 25) who met other specific medical conditions. 28 women ended up participating in the study, 13 in the SCF treatment group and 15 in the placebo group. The study participants each took either SCF or placebo twice a day for twelve weeks and blood and fecal samples were taken before and after the treatment as well as a physical examination including heart rate, waist circumference, body weight, and blood pressure.

After twelve weeks, both the placebo and experimental group saw a decrease in waist circumference and fat mass, thought the SCF group saw a greater decrease in fat mass, blood glucose and other parameters. An analysis of the fecal samples before and after the twelve weeks saw greater clustering in the SCF group than the placebo group. At the genus level, there was significant differences between the two groups and the SCF group saw a greater abundance of genus levels (both groups saw similar levels of phyla changes). They saw specific clustering between patients in the SCF group despite dissimilar clustering prior to treatment. This showed that SCF had an influence on gut microbiota that was dependent on gut bacteria prior to treatment.

This study found differences between bacterial composition in patients who were given the Schisandra chinensis fruit and those in the placebo group. Many of the bacteria that saw an increase in the SCF group, including Akkaermansia, Roseburia, Prevotella, Bifidobacterium, and Bacteroides, had shown an association with reduced obesity levels in previous studies. While decreased waist circumference, body mass, and other weight loss parameters were seen in the SCF group, the results were not statistically significant. Much research has been done to look at ways of altering the microbiome and this study shows us that we should continue to investigate the effects of herbs and fruits on our microbiome.  

A recreational drug may cause memory loss due to the microbiome

There is a common method to induce schizophrenia-like symptoms in mice that is often used in research.  The method involves dosing the mice with a molecule called phenylcyclidine (PCP), better known as the drug angel dust.  There are neurological reasons why this drug should cause schizophrenia-like symptoms in mice, and one consequence of its administration is memory loss.  Researchers from Denmark recently tested if this memory loss was connected to the microbiome and published their results in Physiology and Behavior.

The researchers devised an experiment where groups of mice were either given PCP or a control.  All the mice had their microbiomes tested and underwent a memory test.  The scientists discovered that the PCP did heavily change the microbiome, with many genera increasing in abundance, like Roseburia, Dorea, and Odoribacter.  In addition, the memory performance also seemed to correlate with the microbiome.  As the microbiome rebounded after a 3 week time frame, so did the memory of the mice, even though some other symptoms of the PCP persisted.  Finally, the researchers gave some of the mice that were given PCP antibiotics so as to decrease the population of the microbiome.  The antibiotics were effective in restoring the memory of the mice even within 3 weeks, suggesting a microbiome connection.

The researchers hypothesize that stress caused from taking PCP may be the root cause of the microbiome shifts and memory loss.  Interestingly, some of the bacteria that they identified in the PCP microbiomes had been associated with stress in previous studies.  Here at the AMI we don’t like to preach to our readers, but if any of you use PCP and have a big exam coming up, you may want to consider stopping, or at least taking a probiotic.