Gut-heart axis Photo ©
Gut-heart axis Photo © : Adobe Stock/DK_2020 Gut-Heart-Axis: a dysbiotic gut could increase the risk for cardiovascular disease Laura Ingenlath The gut-heart axis is an emerging concept that emphasizes the crucial link between the gut microbiota and cardiovascular disease (CVD). Recent studies have shown that the gut microbiota plays a central role in the regulation of host metabolism, the development of inflammation and immune function. All three are crucial factors in the pathophysiology of cardiovascular disease. Ecosystem of microorganisms Humans have a diverse and dense ecosystem of microorganisms, known as the human microbiota, which has been known for almost a century. However, researchers are only now beginning to understand many of the functions of these microorganisms for human health and development (Rinninella et al., 2019). The human microbiota comprises more than 100 trillion microbial species, including bacteria, fungi, viruses and protozoa (Rinninella et al., 2019, Cho & Blaser, 2012). Together with their genes (microbiome), these microorganisms form a dynamic microbial community that inhabits different areas of the human body and plays an important role in the health of the host (Rinninella et al., 2019). The area of the human body that harbours the greatest number and diversity of microorganisms is the gastrointestinal tract, more specifically the gut, which has a significant impact on human homeostatic processes such as nutrient metabolism, maintaining the integrity of the intestinal mucosal barrier, regulating satiety, defence against pathogens either by altering pH or secreting antimicrobial peptides or altering cell signalling pathways and the development of the immune system (Yoo, Groer, Dutra, Sarkar & McSkimming, 2020; Talapko, Vcev, Mestrovic, Pustijianac, Juric & Skrlec, 2022). 6 No. 3 November/December 2024
Gut-heart axis At best, these microorganisms live in a symbiotic relationship with their host and although a healthy balance should be sought, there is no single ideal composition as each person has an individual microbiota (Salvucci, 2019; Dogra, Dore & Damak, 2020). The health of the microbiota is influenced by various factors such as genetic predispositions and environmental influences such as diet, infections or antibiotic exposure (Fassarella, Blaak, Penders, Nauta, Smidt & Zoetendal, 2021; Wu & Wu, 2012). Most studies show that the balance between microbial species in the gut microbiota is essential for maintaining the body’s homeostasis (Wu & Wu, 2012). An imbalance in the composition of the microbiota, with a resulting change in its functions, can result in its normal, beneficial state being transformed into a potentially harmful state for human health. This is often accompanied by pro-inflammatory effects and dysregulation of the immune system, which is associated with various diseases (Martinez et al., 2021). There is increasing evidence that the ratio of Firmicutes and Bacteroidetes microbial strains can be used as a biomarker for pathological disorders (Yang et al., 2015). Furthermore, studies show that the gut microbiota has an influence on intestinal diseases and numerous diseases outside the gut such as neurological disorders, cardiovascular diseases, cancer and many others (Clapp, Aurora, Herrera, Bhatia, Wilen & Wakefield, 2017). Prevalence of cardiovascular diseases Over the past decade, cardiovascular disease has become the leading cause of death worldwide, with an estimated 17.9 million deaths per year (Liu & Dai, 2020; Pedersen et al., 2016). In addition to genetic factors, environmental factors and the intestinal microbiota have also been recognised as one of the main factors in the development of CVD (cardiovascular disease). Diabetes, obesity and metabolic syndrome, three major risk factors for cardiovascular disease, have also been linked to gut dysbiosis as a risk factor for the development of cardiovascular disease (Canfora, Meex, Venema & Blaak, 2019; Rahman et al., 2022). One example of the potential link between gut microbiota and CVD is the production of trimethylamine N-oxide (TMAO). A compound that, at high plasma levels, is closely associated with the risk of developing atherosclerosis (Liu & Dai, 2020; Rahman et al., 2022; Almeida, Barata & Fernandes, 2021). Gut microbiota and cardiovascular diseases New findings indicate that a dysbiotic gut microbiota can make a significant contribution to the development of cardiovascular diseases such as atherosclerosis, high blood pressure, coronary heart disease and stroke. Intestinal barrier The intestinal barrier is a complex system that separates the intestinal lumen from the rest of the body (Martel, Chang, Ko, Hwang, Young & Ojcius, 2022). It plays a crucial role in maintaining the health Photo © : Adobe Stock/Akash Tholiya No. 3 November/December 2024 7
