Pathological Mineralization: How Materials Science Aids Medicine

Materials scientists are seeing a growing career in the field of medicine, which endeavors to employ physical principles common to challenges in areas, for instance, in biomedical engineering with advanced technology for biomedical applications. Advances in materials science have given new designs; synthesized materials; and aid in learning chemical, biological, physical, and biomolecular compositions of biomaterials. A specific area of support is disease diagnosis and progression. Materials science methods can give insights hidden at a molecular level.

The heart works like a doorway, maintaining blood movement throughout the organ by four valves. Each valve is made up of flaps, or leaflets (called cusps), that open and close to control blood flow. When impacted by a condition or disease, valves can stop opening fully, partially open, or not open at all. This results in reduced blood flow to the heart and other parts of the body. It also weakens the heart, making it work less effectively than normal. In addition, because the heart has limited regenerative capacity, certain diseases can lead to loss of function, therefore having to surgically remove and replace the heart.

Chambers and Valves of the Heart. Source: Mayo Clinic    A Normal Heart and Heart Valve Problems. Source: Mayo Clinic

However, there are occasions where the heart develops abnormalities, linked to birth defects (congenital heart disease), age-related, or caused by another condition. Hence, the heart will develop issues regarding its functions. A diseased or damaged aortic valve can interfere with blood flow and force the heart to work harder to transmit blood to the rest of the body. For instance, an example of this is Calcific Aortic Valve Disease (CAVD). The aortic valve differentiates the lower left heart chamber (left ventricle) and the body's main artery (aorta, the body’s largest vessel).

CAVD is a degenerative process in which heart valve leaflets progressively stiffen and calcify. Additionally, it is characterized by an active remodeling process accompanied by valve pathological mineralization on soft tissue. This process causes a progressive aortic valve narrowing, and disruption in the proper valve function. Moreover, CAVD is the most common valve disease worldwide. Epidemiological studies show that 2.8% of adults over 75 years old have some CAVD degree, and as many as 25% of adults over 65 years old have at least valvular sclerosis (calcification and thickening of a trileaflet aortic valve in the absence of obstruction of ventricular outflow).

Pathological Mineralization most often results from the deposit of phosphocalcic crystals in the final form of hydroxyapatite within the extracellular matrix (ECM, involved in cellular communication and growth) deposited by the cells involved. The minerals participating in calcification have not been directly analyzed as comprehensively. Materials science methods, for instance electron microscopy, diffraction, spectroscopy (infrared and Raman), thermal analysis, and others have been recently integrated to be applied in biology for the study of hard tissues and biomaterials.

These methods offer unique insights into the structure and composition of tissues and cells at molecular level. While being able to understand the origin of these mineral deposits. These techniques can be applied across a broad range of ECM imaging applications. In addition, they can provide insight on the composition and structure of the biomineralization that occurs within these valves. Being able to understand the biocomposition involved in these types of diseases will aid in providing medical treatments, appropriate therapy, within other remedies. 

Comparison of a Normal Aortic Valve View with a Calcified Aortic Valve. Source: Mayo Clinic

However, there is a deficiency of effective pharmacological approaches for lessening and recovery for CAVD; there are no therapies to slow this disease progression. The merely possible therapy choice is open-heart or transcatheter aortic valve replacement. Heart replacement surgery consists of removing a defective or damaged valve and replacing it with a new valve made from synthetic materials or animal tissue. This surgical treatment can increase blood flow, decrease symptoms, and extend life expectancy.

Furthermore, scientists are researching the knowledge of the roots of CAVD by understanding the multiple pathways for pathological calcification in the human body. By utilizing materials science, researchers have a better comprehension of the type of compounds and molecules found within the cardiovascular tissues of the heart, eventually being able to combat different types of heart diseases, specifically CAVD. Thus, implying further findings in stopping its development worldwide.

 

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