The Genus Alistipes: Role in gut inflammation, cardiovascular diseases, cancer, mental health & Putrefaction pathways

Protein is an essential part of our diet & we consider the more we take protein the better is for our overall health- weight management, muscle building & many more! We are given to believe that more protein is beneficial by doctors, nutritionists &  our fitness trainers. I am going to break this myth of consuming excess protein today & introduce you to a genus of bacteria part of Bacteroidetes phylum which has been linked to various metabolic & neurological disorders.

Alistipes is a new genus of bacteria part of bacteroidetes family, although few in population as compared to other members of bacteroidetes which are relevant in gut dysbiosis & disease.

This genus consist of 13 species of bacterias: Alistipes finegoldii, Alistipes putredinis, Alistipes onderdonkii, Alistipes shahii, Alistipes indistinctus, Alistipes senegalensis, Alistipes timonensis, Alistipes obesi, Alistipes ihumii, Alistipes inops, Alistipes megaguti, Alistipes provencensis, and Alistipes massiliensis.

Before we move ahead, let me give a brief about microbial bacteria science & how it impacts our overall health.

As discussed in our previous blog, gut microbiota is acquired at birth either through mother’s vagina( in as of vaginal birth) or through hospitals & other adults( in case of C-section delivery). Our gut is home to around 40 trillion of bacteria. 90% of diversity & abundance comes from two phylums of bacteria- Firmicutes & Bacteroidetes. Collectively, cells of our gut microbiome consist of more than half of the cells in our body. Epigenetically we are only 1% humans. We look human since human cells are much bigger in size. Human gut microbiota plays an important role in,

1. Regulating immune response, protecting against pathogens & harmful viruses, facilitates digestion process & assists in neuron signaling (communicating with our brain).
2. Imbalance in gut microbiome equilibrium or gut dysbiosis has been linked to host of diseases such as cancer, cardiovascular diseases, Irritable bowel syndrome & neurodegenerative disorders.

Alistipes & Cardiovascular diseases

Let us discuss the role of this genus in occurrence of cardiovascular diseases.

Cardiovascular disease(CVD) is the leading cause of mortality in both developing & developed countries. With the rate of CVD occurrence to rise in future, its relationship with gut dysbiosis has been investigated extensively. Genus Alistipes has been associated with CVD risk factors such as hypertension & diseases such as atrial fibrillation (AF), congestive heart failure (CHF), and atherosclerosis cardiovascular disease (ACVD). In case of hypertension, Alistipes contributes to inflammation. Increase in one of its species- finegoldii is said to be positively correlated with systolic blood pressure (SBP), depicting that this species is a potential driver for gut barrier dysfunction and inflammation in patients with high blood pressure. The inflammation in alistipes is caused by lipopolysaccharides(LPS) which is pro-inflammatory toxin & is said to reduce the butyrate (essential short chain fatty acid that prevents inflammation & improves satiety level) producing bacteria.

CVD such as atrial fibrillation (AF) is prevalent in people suffering from obesity, hypertension & heart failure. Alistipes is closely associated with atrial fibrillation (AF).

Alistipes & Irritable Bowel Disease

Due to the diverse microbial community in our gastrointestinal tract, there is a strong relationship between gut dysbiosis & Irritable bowel disease. The two most common IBS are Crohns diseases(CD) & ulcerative colitis(UC). UC is a chronic inflammatory disease that specifically targets colon( large intestine). A species of alistripes A-finegoldii is a protective species against UC. IN a research, Mice developed colitis when finegoldii was added with Bacteroides eggerthii, a colitis- inducing bacteria, but the severity of the colitis was significantly decreased compared to that of mice with B. eggerthii alone or added with other bacteria such as Parabacteroides distasonis, or Prevotella falsenii. This further indicates that A. finegoldii is a colitis-attenuating bacteria.

Alistipes & cancer

Cancer like cardiovascular diseases causes a high rate of mortality globally. Colorectal cancer is one the most common forms of cancer targeting older individuals. This form of cancer has been linked to gut microbiota dysbiosis. Alistipes is said to contribute to pathogenesis acting as a potential pathogen. A finegoldii promotes potential colorectal cancer. An antimicrobial protein-Lipocalin 2 (LCN 2) reduces iron availability. High concentration of LCN 2( found in fecal samples of patients suffering from IBD) is said to reduce the prevalence of alistipes since iron is essential for regulatory growth of A.finegoldii. To conclude, Alistipes thrives in an inflamed environment that lacks LCN 2 and promotes inflammation and tumor formation. 

Alistipes & Mental Health

Although alistipes are normally found in gastrointestinal tract, it has a potential role to play on diseases with localization outside the gut such as depression, stress, anxiety, chronic fatigue syndrome, autism & ageing. Gut dysbiosis directly impacts the gut-brain axis. People suffering from chronic fatigue syndrome have a high concentration of alistipes in their gut. This supports evidence of high concentration of Alistipes in people suffering from depression & anxiety since people having depression/anxiety struggle with fatigue & stress. In fact, Alistipes disrupts the communication between gut & brain through gut-brain axis & decreases release or serotonin which in any case is linked with occurrence of depression. It is often found that individuals suffering from autism have frequent GI symptoms, speculating due to a dysbiosis within the microbiota. It was found that Alistipes is in high concentration in children suffering from Autism indicating a link between Alistipes & neurodegenerative disorders. However more studies are being undertaken to establish the impact of this genus on disruption of the gut-brain axis.

Alistipes & Putrefaction pathways

Alistipes is a genus of bacteria with a number of immunological & biochemical pathways that are associated with diseases such as IBD, cancer & CVD as mentioned in the above paragraphs. Besides, Genus Alistipes has highest number of Putrefaction pathways among commensal bacteria. PUTREFACTION is fermentation of undigested/excess protein in the gastrointestinal tract(GI) by gut bacteria leading to production of harmful metabolites by bacteria. These metabolites/products such as ammonia, hydrogen sulphide, indole & phenol have been associated with colorectal cancer(CRC). It has been found that Alistipes plays a major role in THF production, indole production & phenol production. THF production is said to release excess ammonia which when absorbed damages colonic cells. Ammonia is also said to contribute to negatively impact intestinal cell growth of cancer cell in case of CRC.

Our gut microbiome has a profound role to play in our overall health & it starts from the time when we  are born. Imbalance in our gut bacteria can result in gut dysbiosis & is considered to be the starting point of chronic health conditions. Be it excess consumption of protein or any other food that cannot be metabolised by your gut, it will lead to inflammation & create digestive issues or even lead to colorectal cancer. Want to know how to optimize your gut to work in favor of your health? Hop on for a free discovery call here to know more.

Sources:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7296073/