Do Gut Microbes Influence Human Blood Pressure?

High blood pressure is the leading cause of heart disease and stroke, killing approximately 7.5 million people worldwide every year.¹The number of people living with high blood pressure worldwide has doubled over the last 40 years, with the problem shifting from wealthy western countries to the developing world.^1-2 The increase is thought to be due to growth in the world population and aging of the population.  But are there potentially other explanations?

A recent review called “Gut Microbiota in hypertension” suggests that other regulatory mechanisms may be at play.³  The most commonly known regulatory mechanism is the bodies handling of salt intake, a known cardiovascular risk.⁴ Salt sensitivity is defined as > 5-10% change in blood pressure response to sodium chloride intake.⁴   A second hypertension regulatory mechanism maybe the human bodies abundance of gut microbes.  Firmicutes and Bacteriodetes and to a lesser extent Actinobacteria and Prteobacteria adapt to human lifestyle modifications such as diet and exercise.^5-7 Gut microbiota regulates approximately 10% of the host’s total mRNA expression (i.e., trascriptome), including those genes related to host immunity, and cellular proliferation and metabolism. ^8-9

Gut microbiota appear to affect blood pressure control by multiple pathways. Short chain fatty acids (SFCA), acetate, butyrate, propionate and lactate, produced by the gut microbiota can influence blood pressure by activation of G protein-couple receptors, releasing renin but this pro-hypertensive change is counterbalanced by microbe stimulation by vasodilatory actions of other G-protein-coupled  receptors.^10-11  Gut microbiota can also influence blood pressure through immunity and inflammation state of the individual, cell metabolism and proliferation.  Antibiotic intake can also affect the level of blood pressure by altering gut microbiota. ³

Control of blood pressure is multifactorial and appears from current science include sorting out recent influences by the human host gut microbiota.  Perhaps the inability to link genetics directly to essential hypertension, especially salt-sensitive hypertension, suggests environmental influences remain to be further elucidated, but our gut microbiota is probably involved.

References:

1. One Billion People Worldwide Now Have High Blood Pressure. https://www.bloodpressureuk.org/mediacentre/Newsreleases/1billionpeopleworldwidenowhavehighbloodpressure (Accessed 03/2019).
2. NCD Risk Factor Collaboration. Worldwide trends in blood pressure from 1975 to 2015: a pooled analysis of 1479 population-based measurement studies with 19·1 million participants. Lancet 2017;389:37-55.
3. Jose PA, Raj D. Gut microbiota in hypertension. Clin Opin Nephrol Hypertens 2015;24(5):403-9.
4. Sullivan JM. Salt sensitivity.  Definition, conception, methodology, and long-term issues. Hypertension 1991;17 (1 suppl):161-8.
5. Qin J, Li R, Raes J, Arumugam M, et al. A human gut microbial gene catalogue established by metagenomic sequencing. Nature 2010;464:59-65.
6. David LA, Maurice CF, Carmody RN, et al. Diet rapidly and reproducibly alters the human gut microbiome. Nature 2014;505:59-65.
7. Petriz BA, Castro AP, Almeida JA, et al. Exercise induction of gut microbiota modification in obese, non-obese and hypertensive rats. BMC Genomics 2014;21:15, 511.
8. Sommer F, Nookaew I, Sommer N, et al. Site-specific programming of the host epithelial transcriptome by the gut microbiota. Genome Biol 2015;16:62.
9. Min YW, Rhee PL. The role of microbiota on the gut immunology. Clin Ther 205;37(5):968-75.
10. Pluznick JL, Protzko RJ, Gevorgyan H, et al. Olfactory receptor responding to gut microbiota-derived signals plays a role in renin section and blood pressure regulation. Proc Natl Acad Sci USA 2013;110:4410-5.
11. Pluznick J. A novel SCFA receptor, the microbiota, and blood pressure regulation. Gut Microbes 2014;5:202-7.