Biomechanical-Structural Correlation of Chordae tendineae in Animal Models: A Pilot Study

Reverse impact of chordae tendineae structural changes on its biomechanical properties as a part of pathogenesis in canine myxomatous mitral valve disease

BACKGROUND

Myxomatous mitral valve disease is the most common cardiac disease among dogs. The mitral valve consists of valve leaflets, chordae tendineae and papillary muscles. Much attention has been given to lesions of the valve leaflets, but there is still a lack of information in the literature about the chordae. During myxomatous mitral valve disease, an episode of chordae rupture can occur. Predisposing factors for such an episode are known in human cardiology.

MATERIALS AND METHODS

The 54 mitral valves were prepared from the hearts of older dogs, from which the chordae tendineae were then isolated. The chordae tendineae were subjected to two tests: biomechanical and histopathological. The first consisted of a uniaxial tensile test to determine the mechanical strength values of chordae tendineae. The histopathological examination was based on a 4-point scale (0-3 scale), which assessed the extent of degenerative changes within chordae tendineae. The biomechanical and histopathological findings were correlated in the statistical analysis.

RESULTS

Degenerated chordae tendineae tended to rupture more rapidly during the static stretching test as compared to healthy chordae. The more advanced the degenerative changes in the chordae tendineae, the more the biomechanical function was affected.

CONCLUSIONS

Degeneration affects the biomechanical properties of the mitral valve chordae tendineae in dogs, as confirmed by chordae tendineae stress studies.

Exploring Unusual Cardiac Complications: Chorda Tendinea Rupture and Pulmonary Valve Vegetation in Infective Endocarditis-A Comprehensive Review

Infective endocarditis (IE) is a severe infection of the endocardium, frequently involving heart valves, and is associated with significant morbidity and mortality. At the same time, traditional complications of IE, such as valvular dysfunction and embolic events, are well-documented, and uncommon cardiac manifestations, such as chorda tendinea rupture and pulmonary valve vegetation, present unique diagnostic and management challenges. This comprehensive review explores the pathophysiology, clinical presentation, diagnostic strategies, and management approaches for IE's chorda tendinea rupture and pulmonary valve vegetation. Through a detailed examination of the literature and discussion of clinical scenarios, we highlight the importance of recognizing these rare complications and discuss the implications for clinical practice. Additionally, we identify knowledge gaps and propose areas for future research to enhance further our understanding and management of these unusual cardiac complications in IE. This review aims to provide clinicians with valuable insights to improve patient care and outcomes in the challenging setting of infective endocarditis.

Gene expression of Postn and FGF7 in canine chordae tendineae and their effects on flexor tenocyte biology

Chordae tendineae, referred to as heart tendinous cords, act as tendons connecting the papillary muscles to the valves in the heart. Their role is analogous to tendons in the musculoskeletal system. Despite being exposed to millions of cyclic tensile stretches over a human's lifetime, chordae tendineae rarely suffer from overuse injuries. On the other hand, musculoskeletal tendinopathy is very common and remains challenging in clinical treatment. The objective of this study was to investigate the mechanism behind the remarkable durability and resistance to overuse injuries of chordae tendineae, as well as to explore their effects on flexor tenocyte biology. The messenger RNA expression profiles of chordae tendineae were analyzed using RNA sequencing and verified by quantitative reverse transcription polymerase chain reaction  and immunohistochemistry. Interestingly, we found that periostin (Postn) and fibroblast growth factor 7 (FGF7) were expressed at significantly higher levels in chordae tendineae, compared to flexor tendons. We further treated flexor tenocytes in vitro with periostin and FGF7 to examine their effects on the proliferation, migration, apoptosis, and tendon-related gene expression of flexor tenocytes. The results displayed enhanced cell proliferation ability at an early stage and an antiapoptotic effect on tenocytes, while treated with periostin and/or FGF7 proteins. Furthermore, there was a trend of promoted tenocyte migration capability. These findings indicated that Postn and FGF7 may represent novel cytokines to target flexor tendon healing. Clinical significance: The preliminary discovery leads to a novel idea for treating tendinopathy in the musculoskeletal system using specific molecules identified from chordae tendineae.