Hypertension: microbiota-targeting treatment. Chin Med J (Engl). 2020;133:1353-1354. [PMID: 31977554 PMCID: PMC7289302 DOI: 10.1097/cm9.0000000000000657]

Gut microbiota and microbiota-derived metabolites in cardiovascular diseases

ABSTRACT

Cardiovascular diseases, including heart failure, coronary artery disease, atherosclerosis, aneurysm, thrombosis, and hypertension, are a great economic burden and threat to human health and are the major cause of death worldwide. Recently, researchers have begun to appreciate the role of microbial ecosystems within the human body in contributing to metabolic and cardiovascular disorders. Accumulating evidence has demonstrated that the gut microbiota is closely associated with the occurrence and development of cardiovascular diseases. The gut microbiota functions as an endocrine organ that secretes bioactive metabolites that participate in the maintenance of cardiovascular homeostasis, and their dysfunction can directly influence the progression of cardiovascular disease. This review summarizes the current literature demonstrating the role of the gut microbiota in the development of cardiovascular diseases. We also highlight the mechanism by which well-documented gut microbiota-derived metabolites, especially trimethylamine N-oxide, short-chain fatty acids, and phenylacetylglutamine, promote or inhibit the pathogenesis of cardiovascular diseases. We also discuss the therapeutic potential of altering the gut microbiota and microbiota-derived metabolites to improve or prevent cardiovascular diseases.

The process of hypertension induced by high-salt diet: Association with interactions between intestinal mucosal microbiota, and chronic low-grade inflammation, end-organ damage

Inflammation and immunity play a major role in the development of hypertension, and a potential correlation between host mucosal immunity and inflammatory response regulation. We explored the changes of intestinal mucosal microbiota in hypertensive rats induced by high-salt diet and the potential link between the intestinal mucosal microbiota and inflammation in rats. Therefore, we used PacBio (Pacific Bioscience) SMRT sequencing technology to determine the structure of intestinal mucosal microbiota, used enzyme-linked immunosorbent assay (ELISA) to determined the proinflammatory cytokines and hormones associated with hypertension in serum, and used histopathology methods to observe the kidney and vascular structure. We performed a potential association analysis between intestinal mucosal characteristic bacteria and significantly different blood cytokines in hypertensive rats induced by high-salt. The results showed that the kidney and vascular structures of hypertensive rats induced by high salt were damaged, the serum concentration of necrosis factor-α (TNF-α), angiotensin II (AngII), interleukin-6 (IL-6), and interleukin-8 (IL-8) were significantly increased (p < 0.05), and the coefficient of immune organ spleen was significantly changed (p < 0.05), but there was no significant change in serum lipids (p > 0.05). From the perspective of gut microbiota, high-salt diet leads to significant changes in intestinal mucosal microbiota. Bifidobacterium animalis subsp. and Brachybacterium paraconglomeratum were the dominant differential bacteria in intestinal mucosal, with the AUC (area under curve) value of Bifidobacterium animalis subsp. and Brachybacterium paraconglomeratum were 1 and 0.875 according to ROC (receiver operating characteristic) analysis. Correlation analysis showed that Bifidobacterium animalis subsp. was correlated with IL-6, IL-8, TNF-α, and Ang II. Based on our results, we can speculated that high salt diet mediated chronic low-grade inflammation through inhibited the growth of Bifidobacterium animalis subsp. in intestinal mucosa and caused end-organ damage, which leads to hypertension.

Current Trends and Challenges of Fecal Microbiota Transplantation-An Easy Method That Works for All?

The gut microbiota refers to bacteria lodges in the gastrointestinal tract (GIT) that interact through various complex mechanisms. The disturbance of this ecosystem has been correlated with several diseases, such as neurologic, respiratory, cardiovascular, and metabolic diseases and cancer. Therefore, the modulation of the gut microbiota has emerged as a potential therapeutic tool; of the various forms of gut microbiota modulation, fecal microbiota transplantation (FMT) is the most approached. This recent technique involves introducing fecal material from a healthy donor into the patient's gastrointestinal tract, aiming to restore the gut microbiota and lead to the resolution of symptoms. This procedure implies a careful donor choice, fine collection and handling of fecal material, and a balanced preparation of the recipient and consequent administration of the prepared content. Although FMT is considered a biological therapy with promising effects, side effects such as diarrhea and abdominal pain have also been claimed, making this a significant challenge in the application of FMT. Bearing this in mind, the present review aims to summarize the recent advances in understanding FMT mechanisms, their impact across different pathological conditions, and the associated side effects, emphasizing the most recent published data.

Physiopathological mechanisms involved in the development of hypertension associated with gut dysbiosis and the effect of nutritional/pharmacological interventions

The gut microbiota dysbiosis represents a triggering factor for cardiovascular diseases, including hypertension. In addition to the harmful impact caused by hypertension on different target organs, gut dysbiosis is capable of causing direct damage to critical organs such as the brain, heart, blood vessels, and kidneys. In this sense, it should be noted that pharmacological and nutritional interventions may influence gut microbiota composition, either inducing or preventing the development of hypertension. Some of the most important nutritional interventions at this level are represented by pro-, pre-, post- and/or syn-biotics, as well as polysaccharides, polyunsaturated fatty acids ω-3, polyphenols and fiber contained in different foods. Meanwhile, certain natural and synthetic active pharmaceutical ingredients, including antibiotics, antihypertensive and immunosuppressive drugs, vegetable extracts and vitamins, may also have a key role in the modulation of both gut microbiota and cardiovascular health. Additionally, gut microbiota may influence drugs and food-derived bioactive compounds metabolism, positively or negatively affecting their biological behavior facing established hypertension. The understanding of the complex interactions between gut microbiome and drug/food response results of great importance to developing improved pharmacological therapies for hypertension prevention and treatment. The purpose of this review is to critically outline the most relevant and recent findings on cardiovascular, renal and brain physiopathological mechanisms involved in the development of hypertension associated with changes in gut microbiota, besides the nutritional and pharmacological interventions potentially valuable for the prevention and treatment of this prevalent pathology. Finally, harmful food/drug interventions on gut microbiota are also described.

Awareness and attitude of fecal microbiota transplantation through transendoscopic enteral tubing among inflammatory bowel disease patients

BACKGROUND

Transendoscopic enteral tubing (TET) has been used in China as a novel delivery route for fecal microbiota transplantation (FMT) into the whole colon with a high degree of patient satisfaction among adults.

AIM

To explore the recognition and attitudes of FMT through TET in patients with inflammatory bowel disease (IBD).

METHODS

An anonymous questionnaire, evaluating their awareness and attitudes toward FMT and TET was distributed among IBD patients in two provinces of Eastern and Southwestern China. Question formats included single-choice questions, multiple-choice questions and sorting questions. Patients who had not undergone FMT were mainly investigated for their cognition and acceptance of FMT and TET. Patients who had experience of FMT, the way they underwent FMT and acceptance of TET were the main interest. Then all the patients were asked whether they would recommend FMT and TET. This study also analyzed the preference of FMT delivery in IBD patients and the patient-related factors associated with it.

RESULTS

A total of 620 eligible questionnaires were included in the analysis. The survey showed that 44.6% (228/511) of patients did not know that FMT is a therapeutic option in IBD, and 80.6% (412/511) of them did not know the concept of TET. More than half (63.2%, 323/511) of the participants stated that they would agree to undergo FMT through TET. Of the patients who underwent FMT via TET [62.4% (68/109)], the majority [95.6% (65/68)] of them were satisfied with TET. Patients who had undergone FMT and TET were more likely to recommend FMT than patients who had not (94.5% vs 86.3%, P = 0.018 and 98.5% vs 87.8%, P = 0.017). Patients’ choice for the delivery way of FMT would be affected by the type of disease and whether the patient had the experience of FMT. When compared to patients without experience of FMT, Crohn’s disease and ulcerative colitis patients who had experience of FMT preferred mid-gut TET (P < 0.001) and colonic TET (P < 0.001), respectively.

CONCLUSION

Patients’ experience of FMT through TET lead them to maintain a positive attitude towards FMT. The present findings highlighted the significance of patient education on FMT and TET.