Mechanistic Review on the Role of Gut Microbiota in the Pathology of Cardiovascular Diseases

Cardiovascular diseases (CVDs), which stand as the primary contributors to illness and death on a global scale, include vital risk factors like hyperlipidemia, hypertension, diabetes, and smoking, to name a few. However, conventional cardiovascular risk factors offer only partial insight into the complexity of CVDs. Lately, a growing body of research has illuminated that the gut microbiome and its by-products are also of paramount importance in the initiation and progression of CVDs. The gastrointestinal tract houses trillions of microorganisms, commonly known as gut microbiota, that metabolize nutrients, yielding substances like trimethylamine-N-oxide (TMAO), bile acids (BAs), short-chain fatty acids (SCFAs), indoxyl sulfate (IS), and so on. Strategies aimed at addressing these microbes and their correlated biological pathways have shown promise in the management and diagnosis of CVDs. This review offers a comprehensive examination of how the gut microbiota contributes to the pathogenesis of CVDs, particularly atherosclerosis, hypertension, heart failure (HF), and atrial fibrillation (AF), explores potential underlying mechanisms, and highlights emerging therapeutic prospects in this dynamic domain.

Integration of transcriptomics, metabolomics, and lipidomics reveals the mechanisms of doxorubicin-induced inflammatory responses and myocardial dysfunction in mice

Doxorubicin (DOX) is an anthracycline antineoplastic agent that has limited clinical utility due to its dose-dependent cardiotoxicity. Although the exact mechanism remains unknown, inflammatory responses have been implicated in DOX-induced cardiotoxicity (DIC). In this study, we analyzed the transcriptomic, metabolomic as well as lipidomic changes in the DOX-treated mice to explore the underlying mechanisms of DIC. We found that continuous intraperitoneal DOX injections (3 mg/kg/d) for a period of five days significantly induced cardiac dysfunction and cardiac injury in male C57BL/6 J mice (8 weeks old). This corresponded to a significant increase in the myocardial levels of IL-4, IL-6, IL-10, IL-17 and IL-12p70. Furthermore, inflammation-related genes such as Ptgs2, Il1b, Cxcl5, Cxcl1, Cxcl2, Mmp3, Ccl2, Ccl12, Nfkbia, Fos, Mapk11 and Tnf were differentially expressed in the DOX-treated group, and enriched in the IL-17 and TNF signaling pathways. Besides, amino acids, peptides, imidazoles, toluenes, hybrid peptides, fatty acids and lipids such as Hex1Cer, Cer, SM, PG and ACCa were significantly associated with the expression pattern of inflammation-related genes. In conclusion, the integration of transcriptomic, metabolomic and lipidomic data identified potential new targets and biomarkers of DIC.

The Interaction of Gut Microbiota and Heart Failure with Preserved Ejection Fraction: From Mechanism to Potential Therapies

Heart failure with preserved ejection fraction (HFpEF) is a disease for which there is no definite and effective treatment, and the number of patients is more than 50% of heart failure (HF) patients. Gut microbiota (GMB) is a general term for a group of microbiota living in humans' intestinal tracts, which has been proved to be related to cardiovascular diseases, including HFpEF. In HFpEF patients, the composition of GMB is significantly changed, and there has been a tendency toward dysbacteriosis. Metabolites of GMB, such as trimethylamine N-oxide (TMAO), short-chain fatty acids (SCFAs) and bile acids (BAs) mediate various pathophysiological mechanisms of HFpEF. GMB is a crucial influential factor in inflammation, which is considered to be one of the main causes of HFpEF. The role of GMB in its important comorbidity-metabolic syndrome-also mediates HFpEF. Moreover, HF would aggravate intestinal barrier impairment and microbial translocation, further promoting the disease progression. In view of these mechanisms, drugs targeting GMB may be one of the effective ways to treat HFpEF. This review focuses on the interaction of GMB and HFpEF and analyzes potential therapies.

The Role of Intestinal Flora and Its Metabolites in Heart Failure

Intestinal flora is a complex collection of microbial communities that participate in the physiological and pathological activities of the human body through various pathways. In recent years, numerous studies have reported that intestinal flora are involved in the occurrence and development of heart failure (HF) and its metabolic products could play an important role in this progression, suggesting a great value in the clinical treatment of this condition. This study reported the interaction between intestinal flora and HF, and with intestinal flora metabolites, such as short-chain fatty acids, trimethylamine N-oxide and bile acids and urotoxins, considered as the starting point, the mechanism of the roles in HF was summarized. Additionally, the current research status and the development prospects of applying flora and metabolites to the clinical therapeutic decision of HF were discussed.

Effect of Qishen granules on isoproterenol-induced chronic heart failure in rats evaluated by comprehensive metabolomics

Qishen granules (QSG), a Chinese herbal formula, has been widely used in the treatment of myocardial ischemic chronic heart failure (CHF) for many years, but its mechanism of action is still unclear. In this study, comprehensive metabolomics was used to investigate the underlying protective mechanisms of QSG in an isoproterenol-induced CHF rat model. A total of 14 biomarkers were identified in serum and 34 biomarkers in urine, which were mainly related to fatty acid metabolism, bile acid metabolism, amino acid metabolism, purine metabolism, vitamin metabolism, and inflammation. Finally, 22 markers were selected for quantitative analysis of serum, urine, and fecal samples to verify the reliability of the results of untargeted metabolomics, and the results were similar to those of untargeted metabolomics. The correlation analysis showed that the targeted quantitative endogenous metabolites and CHF-related indexes were closely related. QSG might alleviate myocardial inflammatory response, oxidative stress, and amino acid metabolism disorder in CHF by regulating the level of endogenous metabolites. This study revealed QSG could regulate potential biomarkers and correlated metabolic pathway, which provided support for the further application of QSG.

Shengmai Yin formula exerts cardioprotective effects on rats with chronic heart failure via regulating Linoleic Acid metabolism

The objective of this study was to investigate the protective effects of Shengmai Yin(SMY) on rats with chronic heart failure(CHF).Sprague-Dawley rats were used to establish a CHF animal model via ligation of the left anterior descending branch of the coronary artery and exhaustive swimming.Echocardiography, serum biochemical indicators and histopathology were used to evaluate the pharmacodynamics of SMY in CHF rats.UPLC-Q-TOF/MS analysis based on serum was performed to identify the potential metabolites in the pathological process of CHF. Metabolic pathway analysis was carried out to elucidate the metabolic network associated with SMY treatment of CHF.Moreover,quantitative real-time PCR (qRT-PCR), Western blotting (WB), and Enzyme-linked immunosorbent assay (ELISA) were used to measure the RNA and protein expression levels in related pathways. Results revealed that SMY significantly restored the cardiac function of CHF rats, reduced the serum biochemical indicators, and alleviated cardiac histological damage. Metabolomics analysis shows that the therapeutic effect of SMY for CHF involves 14 biomarkers and 8 metabolic pathways, especially linoleic acid pathway, to be influenced, which implied the potential mechanism of SMY in treating CHF. Two key indicators Lipoxygenase arachidonic acid 15 lipoxygenase (ALOX15) and Cytochrome P450 1A2(CYP1A2) of linoleic acid metabolism pathway were verified by RT-PCR, WB and ELISA. Verification result showed that compared with the model group, expression levels of ALOX15 and CYP1A2 in SMY group were lower. In conclusion, SMY has cardioprotective effect on chronic heart failure rats, and its mechanism may be related to linoleic acid metabolism pathway.

Therapeutic effects of different polar fractions of hawthorn extract on blood stasis model rats revealed by liquid chromatography-mass spectrometry metabolomics

Hawthorn, a commonly used traditional Chinese medicine, has been suggested to have therapeutic effects on cardiovascular disease. However, effective fractions of hawthorn extract in the treatment of cardiovascular disease, together with possible therapeutic mechanisms, remain unclear. This study aimed to investigate the effects of four different polar fractions of hawthorn extract on blood stasis model rats, and explore the possible metabolic mechanisms by using a liquid chromatography-mass spectrometry metabolomics approach. Evaluation of hemorheology and fibrinogen showed that n-butanol and ethyl acetate fractions of hawthorn extract had significant therapeutic effects on blood stasis model rats. Furthermore, metabolomics analysis showed that n-butanol and ethyl acetate fractions of hawthorn extract could reverse imbalanced biomarkers in plasma and urine of blood stasis model rats. Additionally, metabolic pathway analysis revealed that plasma biomarkers were responsible for several important pathways, including d-glutamine and d-glutamate metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, alanine, aspartate, and glutamate metabolism, sphingolipid metabolism, and arginine biosynthesis. Meanwhile, urine biomarkers were responsible for some important pathways, including phenylalanine metabolism, tyrosine metabolism, and lysine degradation. This study demonstrated that n-butanol and ethyl acetate fractions of hawthorn extract had significant therapeutic effects on blood stasis model rats, and the underlying mechanisms involved multiple metabolic pathways.

Metabolomics study on the periplocin-induced cardiotoxicity and the compatibility of periplocin and Panax notoginseng saponins in reducing cardiotoxicity in rats by GC-MS

Periplocin, as one of the components of cardiac glycosides in Cortex periplocae, exhibited cardiotonic effects. Orally ingesting periplocin in high doses or over prolonged periods would cause serious adverse reactions, especially cardiotoxicity, which limits the applications of periplocin in clinical therapy. It has been reported that Panax notoginseng saponins could be used in compatibility with periplocin to reduce the cardiotoxicity of periplocin. To clarify the mechanisms of periplocin-induced cardiotoxicity and compatibility-pairing in reducing cardiotoxicity, the gas chromatography-mass spectrometry method was used to detect and analyze the metabolic profiles of rat plasma and urine samples after oral administration of periplocin, Panax notoginseng saponins, and the different compatibility ratios of periplocin and Panax notoginseng saponins. The multivariate statistical analysis method was used to screen and identify the biomarkers. A total of 49 potential biomarkers (28 in plasma and 21 in urine) associated with periplocin-induced cardiotoxicity were identified. Seven pathways were found through metabolomic pathway analysis. Moreover, the levels of 42 biomarkers (22 in plasma and 20 in urine) were close to normal after compatibility pairing. By analyzing the relative metabolic pathways, Panax notoginseng saponins could effectively reduce the cardiotoxicity of periplocin by affecting the tricarboxylic acid cycle, energy metabolism, and arachidonic acid metabolism.