A recent study published in Nature has explored the fractal structure of the heart, revealing its influence on susceptibility to cardiovascular disease.
Leonardo da Vinci heart sketch
The inner surface of the chambers of the mature human heart are complex. They are lined with a fenestrated network of muscular trabeculae that extend into the cavity. They are thought to be remnants of embryonic development; however, the function and genetic architecture of these trabeculae are unknown. Half a millennium on since Leonardo da Vinci sketched these intricate muscles, only now are we beginning to understand the importance of trabeculae for human health.
The study, led by researchers from the Medical Research Council (MRC) London Institute of Medical Sciences at Imperial College London, is the first to demonstrate the important role of these muscular strands in heart function.
The team used deep learning image analysis to analyse cardiac magnetic resonance (CMR) imaging data from 18,096 participants from the UK Biobank. They then were able to perform a genome-wide association study (GWAS) to investigate image-derived phenotypes of trabeculae.
Researchers found that the trabeculae muscles form a repeating geometric pattern known as a fractal. This pattern is in other structures, such as snowflakes. They suggest that these muscular strands are important in increasing the efficiency of blood flow through the organ. They identified 16 significant loci that linked with either molecular or physiological cardiac phenotypes. In particular, two trabeculae-associated genes, MTSS1 and GOSR2, linked to pathways involved in cytoskeletal actin dynamics.
Association with cardiovascular disease
The team also explored the association of trabeculae-associated loci with cardiovascular disease. They found a causal relationship between trabecular morphology and risk of cardiovascular disease. For both dilated cardiomyopathy and heart failure, they found that loci associated with increasing trabeculation also associated with increased susceptibility to disease.
These findings have provided a previously unknown role for trabeculae in the function of the mature adult heart. Most importantly, they have revealed the influence of these trabeculae on susceptibility to cardiovascular disease. Heart failure is a devastating condition. Despite medical advancements, there is still no cure for this condition. As a result, survival rates remain poor. This groundbreaking research opens doors for new ways to understand how heart disease develops and how it could possibly be treated.
Dr Declan O’Regan, Consultant Radiologist at Imperial College London and study lead, stated:
“We now know that many of the genes that determine the development of trabeculae are also important in heart failure. Our next step is to figure out exactly how trabeculae protect against heart failure and whether images of these structures could be used to predict heart failure risk. Better understanding trabeculae, their functions and the genes which control them could lead to new treatments for heart failure.”