Showing posts with label clinical study. Show all posts
Showing posts with label clinical study. Show all posts

Wednesday, December 1, 2021

FMO3 and COVID-19

Flavin-containing monooxygenase 3 (FMO3) enzyme is a seemingly insignificant enzyme that normally converts fishy-smelling trimethylamine (TMA) into a neutral trimethylamine-N-oxide (TMAO). The amounts of this highly-specialized detoxifying enzyme are highly variable. It depends on the age, sex hormones, infections (estradiol and testosterone, hepatitis virus have been found to reduce FMO3 capacity), obesity traits and diseases such as diabetes. The difference can be up to 20-fold between individuals. Mutations in the FMO3 gene cause low metabolic capacity associated with the disorder trimethylaminuria (TMAU) that attracts little biomedical interest.  This condition, however, might matter more than it seems.

Could there be a link between FMO3 and SARS-CoV-2 infection and vaccination? 

Individuals differ in their susceptibility to viral infections and genes contribute to the risk score. Less than 10% of humans infected with Mycobacterium tuberculosis develop TB, partially because of polymorphism in Tyrosine kinase (TYK2, P1104A) also responsible for severe COVID-19. Early in the pandemic, it was discovered that SARS-CoV-2 infection is dependent on the ACE2 receptor for cell entry and the serine protease TMPRSS2 for spike protein priming. ACE2 expression, indeed, influences COVID-19 risk and a rare variant located close to this gene was found to confer protection against COVID-19, possibly by decreasing ACE2 expression. Interestingly, FMO3 is one of the few genes with expression correlated to ACE2 [Sungnak et al, 2020] along with genes associated with immune functions. 

Coronavirus disease is associated with increased risk of thrombotic events. According to recent research, low levels of FMO3 protect against thrombosis [Shih et al, 2019] while some FMO3 mutations confer higher risk [Oliveira-Filho et al, 2021]. FMO3 rs1736557 might increase the anti‐platelet efficacy of clopidogrel [Zhu et al, 2021]. Genetic risk can be mediated by gut microbiota [Gabashvili, 2020]. There are also associations with other diseases such as diabetes, renal and cardiovascular conditions increasing risk of severe COVID-19. 

Studying trimethylaminuria-like conditions might help in developing strategies for prevention and therapy of other diseases, including COVID-19.

Our COVID-19 disease and vaccines study [NCT04832932, Gabashvili, 2021] compares side-effects of vaccines and clinical course of infections (including vaccine breakthroughs) in several cohorts including MEBO and TMAU. You can help by enrolling and participating in this online survey in English or Spanish.


Andreakos E, Abel L, Vinh DC, Kaja E, Drolet BA, Zhang Q, O’Farrelly C, Novelli G, Rodríguez-Gallego C, Haerynck F, Prando C. A global effort to dissect the human genetic basis of resistance to SARS-CoV-2 infection. Nature immunology. 2021 Oct 18:1-6. 

Gabashvili IS. Cutaneous Bacteria in the Gut Microbiome as Biomarkers of Systemic Malodor and People Are Allergic to Me (PATM) Conditions: Insights from a Virtually Conducted Clinical Trial. JMIR Dermatology. 2020 Nov 4;3(1):e10508.  

Gabashvili IS. Community-Based Phenotypic Study of Safety, Tolerability, Reactogenicity and Immunogenicity of Emergency-Use-Authorized Vaccines Against COVID-19 and Viral Shedding Potential of Post-Vaccination Infections: Protocol for an Ambispective study. medRxiv 2021.06.28.21256779; doi:

Liu W, Wang C, Xia Y, Xia W, Liu G, Ren C, Gu Y, Li X, Lu P. Elevated plasma trimethylamine-N-oxide levels are associated with diabetic retinopathy. Acta Diabetologica. 2021 Feb;58(2):221-9.

Janmohamed A, Dolphin CT, Phillips IR, Shephard EA. Quantification and cellular localization of expression in human skin of genes encoding flavin-containing monooxygenases and cytochromes P450. Biochemical pharmacology. 2001 Sep 15;62(6):777-86.

Oliveira-Filho AF, Medeiros PF, Velloso RN, Lima EC, Aquino IM, Nunes AB. Trimethylaminuria and Vascular Complications. Journal of the Endocrine Society. 2021 Apr;5(Supplement_1):A313-4. 

Zhu KX, Song PY, Li MP, Du YX, Ma QL, Peng LM, Chen XP. Association of FMO3 rs1736557 polymorphism with clopidogrel response in Chinese patients with coronary artery disease. European Journal of Clinical Pharmacology. 2021 Mar;77(3):359-68.

Sungnak W, Huang N, Bécavin C, Berg M, Queen R, Litvinukova M, Talavera-López C, Maatz H, Reichart D, Sampaziotis F, Worlock KB. SARS-CoV-2 entry factors are highly expressed in nasal epithelial cells together with innate immune genes. Nature medicine. 2020 May;26(5):681-7.

Shih, D.M., Zhu, W., Schugar, R.C., Meng, Y., Jia, X., Miikeda, A., Wang, Z., Zieger, M., Lee, R., Graham, M. and Allayee, H., 2019. Genetic deficiency of Flavin-containing monooxygenase 3 (Fmo3) protects against thrombosis but has only a minor effect on plasma lipid levels—brief report. Arteriosclerosis, thrombosis, and vascular biology, 39(6), pp.1045-1054. 

Wednesday, December 4, 2019

Saturday, November 30, 2019

Concluding the MEBO-uBiome study

We are very close to concluding our clinical trial NCT03582826 ​according to the pre-specified protocol. 

Recruitment for our microbiome study commenced in June 2018 and completed in December 2018. The last batch of raw FASTQ sequences and raw taxonomy-level abundance summaries was received in October 2019. We had to spend more time on collecting and processing annotation data (medical histories, dietary intakes, medications, etc), ensuring quality, completeness, consistency and validity, and defining best approaches of dealing with "missing values".

We have now completed final data collection for the primary and secondary outcome measures.

...  Read more ... 

Thursday, August 29, 2019

Reducing the stigma of odor disorders

Some conditions - such as obesity, depression and functional odor disorders - come with a social stigma. Understanding the etiology of these conditions helps to avoid stereotypes and find remedies. 

Metabolomics analysis of morning urine samples helped to evaluate the heterogeneity of MEBO population as good as challenge tests, procedures used to induce symptoms and assess resilience to perturbations caused by sugars. 

...  Read more ... 

Sunday, July 21, 2019

How do you feed your microbiome?

As we are gearing up for final stage of our clinical study NCT03582826, we are looking at different subgroups of our participants, to find more precise, personalized and powerful solutions for everyone. 

We know, that genes and environment always combine to make us who we are. We already talked about some of those seemingly less important genes - such as ABO blood group. The environmental factors include diet, exercise, social environments (such as social support), varying conditions and situations.   

According to descriptions of diets and lifestyle submitted by our participants, about 25% of them are taking commercial probiotic products, about the same number as those who had chicken as the main staple of their kitchen (see word cloud depiction of diet keywords on the right). About 2% take commercial prebiotics, but many more eat prebiotic foods (such as oats/oatmeal, bananas, apples and nuts shown in green). 4% eats onions and about the same percentage actively avoids it.  Milk, Rice, Bread and Pasta were among the most popular foods, after chicken. 

The world is eating less meat overall, and a few years ago, among the meat eaters, the scale tipped from greater consumption of beef to greater consumption of chicken.
This is even more pronounced in MEBO population. 

Half of MEBO population takes vitamins and  supplements.  The most popular among them is Zinc closely followed by Magnesium and Enzymes. Also popular are multivitamins, Calcium,  Resveratol, Vitamin B12, Charcoal, Chlorophyll, Ashwagandha, Biotin, Primrose oil, Omega 3 and Livercare. Blood pressure drugs are among the most used medications.

This information will be useful in understanding differences in microbiomes of subjects with similar symptoms. We might already be observing interesting trends. Certain supplements, for example, seem to benefit some blood group more than others. Same about foods naturally rich in certain minerals and vitamins.

We'll talk about this next time.

Friday, November 30, 2018

On what's in your head, the downside of diversity and deodorizing bacteria: preliminary results of NCT03582826

Mirrored from Aurametrix, preliminary results of NCT03582826:

By now, 105 uBiome kits were registered in our Quality of Life form (out of 300+ sets sent). 16 volunteers have submitted all 3 samples and 23 registered one or two kits. Over half of our participants have not yet started the study. We hope that this post will answer some of their questions on where to start.

The goal of MEBO Gut Microbiome study is to identify microbial communities associated with flare ups and remission of systematic malodor or PATM conditions.  Participants are asked to answer MEBO Quality of Life (QoL) questionnaire about the last 24 hrs before every sample is taken. The Questionnaire is embedded into English and Spanish posts about the study.  The answers are used to calculate total QoL score that increases with less odor and more wellbeing. The questionnaire evaluates physical health, psychological health, social support and environment such as diet and exercise. A separate score is calculated for MEBO (malodor/PATM) symptoms.

This post is about preliminary results of the first 41 uBiome kits representing samples from 24 participants. Quality of Life scores varied from 55 to 149 (best, "ideal" quality of life would be 150), while MEBO scores ranged from 3 (experienced MEBO/PATM symptoms "all the time" and odor was lingering for hours at 10 feet and farther) to 25 (100% odor free).

The pie chart on the right shows social environment for MEBO volunteers: almost half of study participants had active social lives interacting with over 8 people per day. Almost 20% of social interactions were entirely positive, while 10% were entirely negative. Social support did not correlate with MEBO symptoms and it was not predictor nor protective of malodor.

Graphs of depressive feelings vs odors is another prove that even with stress as a trigger, body odors are not all in your head. Obviously, those free of malodors tend to be happier, but it's possible to control depression even with worst MEBO symptoms and happy mood, alone, does not help to control the symptoms.

uBiome provides a multitude of measurements characterizing gut microbiomes. One of the most widely used metrics is gut diversity metrics.

Microbial diversity is cornerstone of a good health and decreased diversity is likely to be associated with poor wellbeing including malodors. Our data, however, show that most MEBO volunteers have healthy diversity scores that do not correlate with incidence of odors. Correlation is observed only for  cases of very low, unhealthy diversity, especially for total quality of life scores as opposed to just malodor symptoms. Even more so, MEBO volunteers in remission, completely free of odors, had healthy,  but not the very best diversity scores.

In extremely diverse communities, people may be less inclined to trust each other, vote and volunteer for activities. In people not suffering from uncontrollable odors, microbes and hosts have a balanced dialogue, and form symbiotic relationships beneficial for both parties.

Could it be that MEBO sufferers have more "smelly" bacteria and less bacteria neutralizing the smell?  Levels of traditional probiotic strains in the study participants do not seem to correlate with their odor levels. As more data is accumulated, interesting patterns are emerging for less common bacteria. An example is Anaerovorax, bacterium that processes putrid-smelling compounds produced by clostridia, pseudomonads, lactic acid and other bacteria from amino acids in food. Anaerovorax is observed in only 3% of uBiome samples, but it is present in a quarter of MEBO participants. Plotting its levels in all samples with Anaerovorax present against the scores representing improvement of MEBO symptoms (from worst odor to no odor), shows a clear trendline - the more Anaerovorax, the less odor. We note that this seem to be the case for ONLY a subset of study participants. For example, participants #901298 and #901240 who contributed 2 samples each into the first 41-sample-set, had 0 Anaerovorax on their worse day and over 0.03% Anaerovorax on their better days. # 901240 submitted 2 "bad day" samples (which is perfectly fine - as it still yielded much needed data!) had a little more Anaerovorax on a slightly better day. #90346 had experienced exactly the same MEBO symptoms on both days of sampling, but the result with 0 Anaerovorax corresponded to a worse Quality of Life score. #90365 experienced exactly the same symptoms for days with and without Anaerovorax, and had the same Quality of Life Score, but there was a noticeable difference in diet. This person had more Anaerovorax when consumed more odor triggers in food (onions and vinegar).

There is not much known about the role of Anaerovorax in human gut. It is proposed to increase when adding meat to a usually vegetarian diet and with increased fasting insulin levels. It is also increased in healthy preadolescent children (7 to 12 years old) and by minerals such as Zinc and Manganese.

Levels of TMA-producing bacteria such as Desulfibrio and Bacteroides seem to lower when odor levels are decreasing in most cases, although signal-to-noise ratio is weak and the dependence is very individual (see Figure). The trend is similar for #901214, #90265, #900841 and #901273. #901253 is one of the outliers: MEBO symptoms in this case were improving with higher levels of Bacteroides and lover diversity (and a much stricter diet).

Bacteroides maintain a complex and generally beneficial relationship with the host. The genus Bacteroides makes up to 30% of the bacteria in the human gut. Levels of Bacteroides increase with rapid weight loss. Specific species of Bacteroides, have a role in preventing infection with Clostridium difficile. Level of Bacteroides, however, increase (or significantly decrease) in inflammatory bowel disease and chronic fatigue syndrome.
Lactobacillus and bifidobacteria probiotics, garlic, walnuts and barley could all decrease levels of Bacteroides. Polydextrose (dietary fiber found in traditional bakery items, beverages, dairy products and sauces) not only decreases Bacteroides but also increases probiotic strains of Lactobacillus and Bifidobacterium.

These are only preliminary results. We'll be looking at more complex patterns in bacterial community structures associated with different subgroups of study participants. We'll be posting new findings as we mine more data and get additional results.

If you have not started the study yet, we hope that this post encourages you to start participating. As you see, every data point counts, even if the results of your experimentation and odor reduction approaches are not as good as we wished.


Vemuri R, Gundamaraju R, Shastri MD, Shukla SD, Kalpurath K, Ball M, Tristram S, Shankar EM, Ahuja K, Eri R. Gut Microbial Changes, Interactions, and Their Implications on Human Lifecycle: An Ageing Perspective. BioMed research international. 2018;2018.

Zhang Q, Xiao X, Li M, Yu M, Ping F, Zheng J, Wang T, Wang X. Vildagliptin increases butyrate-producing bacteria in the gut of diabetic rats. PloS one. 2017 Oct 16;12(10):e0184735.

Roeder J, Schink B. Syntrophic degradation of cadaverine by a defined methanogenic coculture. Applied and environmental microbiology. 2009 Jul 15;75(14):4821-8.

Lau SK, Teng JL, Chiu TH, Chan E, Tsang AK, Panagiotou G, Zhai SL, Woo PC. Differential Microbial Communities of Omnivorous and Herbivorous Cattle in Southern China. Computational and structural biotechnology journal. 2018 Jan 1;16:54-60.

Filocamo A, Nueno-Palop C, Bisignano C, Mandalari G, Narbad A. Effect of garlic powder on the growth of commensal bacteria from the gastrointestinal tract. Phytomedicine. 2012 Jun 15;19(8-9):707-11.

Cruden DL, Galask RP. Reduction of trimethylamine oxide to trimethylamine by Mobiluncus strains isolated from patients with bacterial vaginosis. Microbial Ecology in Health and Disease. 1988 Jan 1;1(2):95-100.

Craciun S, Balskus EP. Microbial conversion of choline to trimethylamine requires a glycyl radical enzyme. Proceedings of the National Academy of Sciences. 2012 Dec 26;109(52):21307-12.